U.S. patent application number 10/051079 was filed with the patent office on 2002-07-25 for shift actuator for a transmission.
Invention is credited to Kunisue, Motoaki, Yamamoto, Yasushi.
Application Number | 20020096009 10/051079 |
Document ID | / |
Family ID | 27345780 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020096009 |
Kind Code |
A1 |
Yamamoto, Yasushi ; et
al. |
July 25, 2002 |
Shift actuator for a transmission
Abstract
A shift actuator for a transmission, which actuates, in a
direction of shift, a shift lever for operating a synchronizing
device of the transmission, the shift actuator comprising a first
electromagnetic solenoid and a second electromagnetic solenoid for
actuating an operation member coupled to the shift lever in the
directions opposite to each other. Each of the first
electromagnetic solenoid and the second electromagnetic solenoid
comprises a casing, a fixed iron core disposed in the casing, a
moving iron core arranged to be allowed to approach, and separate
away from, the fixed iron core, an operation rod mounted on the
moving iron core to engage with the operation member, and an
electromagnetic coil arranged between the casing and the fixed iron
core as well as the moving iron core.
Inventors: |
Yamamoto, Yasushi;
(Kanagawa, JP) ; Kunisue, Motoaki; (Kanagawa,
JP) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
27345780 |
Appl. No.: |
10/051079 |
Filed: |
January 22, 2002 |
Current U.S.
Class: |
74/473.12 |
Current CPC
Class: |
Y10T 74/2003 20150115;
F16H 61/32 20130101; Y10T 74/2011 20150115; Y10T 74/20201
20150115 |
Class at
Publication: |
74/473.12 |
International
Class: |
F16H 059/04; F16H
061/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2001 |
JP |
2001-13161 |
Feb 16, 2001 |
JP |
2001-40070 |
Feb 16, 2001 |
JP |
2001-40592 |
Claims
What we claim is:
1. A shift actuator for a transmission, which actuates, in a
direction of shift, a shift lever for operating a synchronizing
device of the transmission, the shift actuator comprising: a first
electromagnetic solenoid and a second electromagnetic solenoid for
actuating an operation member coupled to said shift lever in the
directions opposite to each other; each of said first
electromagnetic solenoid and said second electromagnetic solenoid
comprising a casing, a fixed iron core disposed in said casing, a
moving iron core arranged to be allowed to approach, and separate
away from, said fixed iron core, an operation rod mounted on said
moving iron core to engage with said operation member, and an
electromagnetic coil arranged between said casing and said fixed
iron core as well as said moving iron core.
2. A shift actuator for a transmission according to claim 1,
wherein a stepped protuberance is formed on either one of the
opposing surfaces of said fixed iron core and of said moving iron
core, a stepped recess is formed in the other surface to correspond
to said stepped protuberance, and a position at which an edge of
said protuberance and an edge of said recess become closest to each
other is so constituted as to correspond to the synchronizing
position of said synchronizing device.
3. A shift actuator for a transmission, which actuates, in a
direction of shift, a shift lever for operating a synchronizing
device of the transmission, the shift actuator comprising: a first
electromagnetic solenoid and a second electromagnetic solenoid for
actuating an operation member coupled to said shift lever in the
directions opposite to each other; each of said first
electromagnetic solenoid and said second electromagnetic solenoid
comprising an electromagnetic coil, a fixed iron core disposed in
said electromagnetic coil, a moving iron core arranged to be
allowed to approach, and separate away from, said fixed iron core,
a fixed yoke having an inner peripheral surface opposing an outer
peripheral surface of said moving iron core, and an operation rod
mounted on said moving iron core to engage with said operation
member; and the opposing areas of said moving iron core and said
fixed yoke being so constituted as to decrease, at a position where
said fixed iron core ceases to attract said moving iron core.
4. A shift actuator for a transmission according to claim 3,
wherein a stepped protuberance is formed on either one of the
opposing surfaces of said fixed iron core and of said moving iron
core, a stepped recess is formed in the other surface to correspond
to said stepped protuberance, and a position at which an edge of
said protuberance and an edge of said recess become closest to each
other is so constituted as to correspond to the synchronizing
position of said synchronizing device.
5. A shift actuator for a transmission, having a first
electromagnetic solenoid and a second electromagnetic solenoid for
actuating, in the directions opposite to each other, an operation
member coupled to the shift lever to operate a synchronizing device
of the transmission, wherein each of said first electromagnetic
solenoid and said second electromagnetic solenoid comprises an
electromagnetic coil, a fixed iron core excited by said
electromagnetic coil, a first moving iron core arranged to be
allowed to approach, and separate away from, said fixed iron core,
a second moving iron core fitted to an outer peripheral surface of
said first moving iron core so as to slide therealong, and an
operation rod mounted on said first moving iron core to engage with
said operation member; said fixed iron core having a first
attraction portion for attracting said first moving iron core and a
second attraction portion for attracting said second moving iron
core, and said first moving iron core being provided with a
limiting means for limiting said second moving iron core from
moving toward the side of said fixed iron core, and said second
moving iron core and said first moving iron core being so
constituted as to move together, by the action of said limiting
means, until said second moving iron core comes in contact with
said second attraction portion, then, said first moving iron core
alone moving toward said first attraction portion after said second
moving iron core has come in contact with said second attraction
portion, and a position at which said second moving iron core comes
in contact with said second attraction portion being so set as to
correspond to a position just after a synchronizing position of
said synchronizing device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a shift actuator for a
transmission, which actuates, in a direction of shift, a shift
lever for operating a synchronizing device of the transmission
mounted on a vehicle.
DESCRIPTION OF THE RELATED ART
[0002] As the shift actuator for a transmission, which actuates, in
a direction of shift, a shift lever for operating a synchronizing
device of the transmission, there has been generally used a fluid
pressure cylinder which utilizes the fluid pressure such as air
pressure or hydraulic pressure as a source of actuation. The shift
actuator using the fluid pressure cylinders requires a piping for
connecting the source of fluid pressure to the actuators, an
electromagnetic change-over valve for changing over the flow
passage of the operation fluid, and space for the arrangement
thereof, resulting in an increase in the weight of the device as a
whole.
[0003] In recent years, there has been proposed an actuator
constituted by an electric motor as a shift actuator for a
transmission mounted on a vehicle which is provided with neither a
source of the compressed air nor a source of the hydraulic
pressure. The shift actuator constituted by the electric motor
needs neither the piping for connection to the source of fluid
pressure nor the electromagnetic change-over valve, unlike the
actuators that use fluid pressure cylinders, and can, hence, be
constituted in a compact size as a whole and in a reduced
weight.
[0004] The actuator using an electric motor needs a speed reduction
mechanism for obtaining a predetermined actuating force. As the
speed reduction mechanism, there have been proposed the one using a
ball-screw mechanism and the one using a gear mechanism. However,
the actuators using the ball-screw mechanism and gear mechanism are
not necessarily satisfactory in regard to the durability of the
ball-screw mechanism and the gear mechanism, in regard to the
durability and the operation speed of the electric motor.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide a shift
actuator for a transmission, which features excellent durability
and a high operation speed.
[0006] In order to achieve the above-mentioned object according to
the present invention, there is provided a shift actuator for a
transmission, which actuates, in a direction of shift, a shift
lever for operating a synchronizing device of the transmission, the
shift actuator comprising:
[0007] a first electromagnetic solenoid and a second
electromagnetic solenoid for actuating an operation member coupled
to the shift lever in the directions opposite to each other;
[0008] each of the first electromagnetic solenoid and the second
electromagnetic solenoid comprising a casing, a fixed iron core
disposed in the casing, a moving iron core arranged to be allowed
to approach, and separate away from, the fixed iron core, an
operation rod mounted on the moving iron core to engage with the
operation member, and an electromagnetic coil arranged between the
casing and the fixed iron core as well as the moving iron core.
[0009] It is desired that a stepped protuberance is formed on
either one of the opposing surfaces of the fixed iron core and of
the moving iron core, a stepped recess is formed in the other
surface to correspond to the stepped protuberance, and a position
at which an edge of the protuberance and an edge of the recess
become closest to each other is so constituted as to correspond to
the synchronizing position of the synchronizing device.
[0010] According to the present invention, further, there is
provided a shift actuator for a transmission, which actuates, in a
direction of shift, a shift lever for operating a synchronizing
device of the transmission, the shift actuator comprising:
[0011] a first electromagnetic solenoid and a second
electromagnetic solenoid for actuating an operation member coupled
to the shift lever in the directions opposite to each other;
[0012] each of the first electromagnetic solenoid and the second
electromagnetic solenoid comprising an electromagnetic coil, a
fixed iron core disposed in the electromagnetic coil, a moving iron
core arranged to be allowed to approach, and separate away from,
the fixed iron core, a fixed yoke having an inner peripheral
surface opposing an outer peripheral surface of the moving iron
core, and an operation rod mounted on the moving iron core to
engage with the operation member; and
[0013] the opposing areas of the moving iron core and the fixed
yoke being so constituted as to decrease, at a position where the
fixed iron core ceases to attract the moving iron core.
[0014] It is desired that a stepped protuberance is formed on
either one of the opposing surfaces of the fixed iron core and of
the moving iron core, a stepped recess is formed in the other
surface to correspond to the stepped protuberance, and a position
at which an edge of the protuberance and an edge of the recess
become closest to each other is so constituted as to correspond to
the synchronizing position of the synchronizing device.
[0015] According to the present invention, there is further
provided a shift actuator for a transmission, comprising a first
electromagnetic solenoid and a second electromagnetic solenoid for
actuating, in the directions opposite to each other, an operation
member coupled to the shift lever to operate a synchronizing device
of the transmission;
[0016] each of the first electromagnetic solenoid and the second
electromagnetic solenoid including an electromagnetic coil, a fixed
iron core excited by the electromagnetic coil, a first moving iron
core arranged to be capable of being contacted with, and separate
away from, the fixed iron core, a second moving iron core fitted to
an outer peripheral surface of the first moving iron core so as to
slide therealong, and an operation rod mounted on the first moving
iron core to engage with the operation member; the fixed iron core
having a first attraction portion for attracting the first moving
iron core and a second attraction portion for attracting the second
moving iron core, and the first moving iron core being provided
with a limiting means for limiting the second moving iron core from
moving toward the side of the fixed iron core; and the second
moving iron core and the first moving iron core moving together, by
the action of the limiting means, until the second moving iron core
comes in contact with the second attraction portion, then, the
first moving iron core alone moving toward the first attraction
portion after the second moving iron core has come in contact with
the second attraction portion, and a position at which the second
moving iron core comes in contact with the second attraction
portion being so set as to correspond to a position just after a
synchronizing position of the synchronizing device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a sectional view illustrating a gear change device
provided with a shift actuator constituted according to a first
embodiment of the present invention;
[0018] FIG. 2 is a sectional view along the line A-A in FIG. 1;
[0019] FIG. 3 is a view illustrating the operation of a select
actuator that constitutes the gear change device shown in FIG. FIG.
4 is a sectional view along the line B-B in FIG. 1;
[0020] FIG. 5 is a sectional view illustrating the shift actuator
constituted according to a second embodiment of the present
invention;
[0021] FIG. 6 is a sectional view illustrating the shift actuator
constituted according to a third embodiment of the present
invention;
[0022] FIG. 7 is a view illustrating the shift stroke positions of
a synchronizing device corresponding to the operation states of the
shift actuator according to the third embodiment shown in FIG.
6;
[0023] FIG. 8 is a view illustrating the shift stroke positions of
a synchronizing device corresponding to the operation states of the
shift actuator according to the third embodiment shown in FIG.
6;
[0024] FIG. 9 is a sectional view illustrating the shift actuator
constituted according to a fourth embodiment of the present
invention;
[0025] FIG. 10 is a diagram illustrating a relationship between the
operation positions and the thrust of the shift actuator;
[0026] FIG. 11 is a sectional view illustrating the shift actuator
constituted according to a fifth embodiment of the present
invention;
[0027] FIG. 12 is a view illustrating the operation states of the
shift actuator according to the fifth embodiment shown in FIG.
11;
[0028] FIG. 13 is a view illustrating the operation states of the
shift actuator according to the fifth embodiment shown in FIG.
11;
[0029] FIG. 14 is a sectional view illustrating the shift actuator
constituted according to a sixth embodiment of the present
invention;
[0030] FIG. 15 is a view illustrating the operation states of the
shift actuator according to the sixth embodiment shown in FIG.
14;
[0031] FIG. 16 is a sectional view illustrating the shift actuator
constituted according to a seventh embodiment of the present
invention;
[0032] FIG. 17 is a view illustrating the operation states of the
shift actuator according to the seventh embodiment shown in FIG.
16;
[0033] FIG. 18 is a sectional view illustrating the shift actuator
constituted according to an eighth embodiment of the present
invention;
[0034] FIG. 19 is a diagram illustrating a relationship between the
operation positions and the thrust of the shift actuator;
[0035] FIG. 20 is a sectional view illustrating the shift actuator
constituted according to a ninth embodiment of the present
invention;
[0036] FIG. 21 is a view illustrating the operation states of the
shift actuator according to the ninth embodiment shown in FIG. 21;
and
[0037] FIG. 22 is a diagram illustrating a relationship between the
operation positions and the thrust of the shift actuator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Preferred embodiments of the shift actuator for a
transmission constituted according to the present invention will
now be described in further detail with reference to the
accompanying drawings.
[0039] FIG. 1 is a sectional view illustrating a gear change device
provided with a shift actuator constituted according to a first
embodiment of the present invention, and FIG. 2 is a sectional view
along the line A-A in FIG. 1.
[0040] A gear change device 2 according to the illustrated
embodiment is constituted by a select actuator 3 and a shift
actuator 5. The select actuator 3 has three cylindrical casings
31a, 31b and 31c. A control shaft 32 is disposed in the three
casings 31a, 31b and 31c, and both ends of the control shaft 32 are
rotatably supported by the casings 31a and 31c on both sides via
bearings 33a and 33b. A spline 321 is formed in an intermediate
portion of the control shaft 32. A cylindrical shift sleeve 35
constituted integratedly with a shift lever 34 is spline-fitted to
the spline 321 so as to slide in the axial direction. The shift
lever 34 and the shift sleeve 35 are made of a nonmagnetic material
such as a stainless steel, and the shift lever 34 is disposed being
inserted in an opening 311b formed in a lower portion of the
central casing 31b. An end of the shift lever 34 is so constituted
as to suitably engage with shift blocks 301, 302, 303 and 304 which
are disposed at a first select position SP1, at a second select
position SP2, at a third select position SP3 and at a fourth select
position SP4 and are constituting a shift mechanism for a
transmission that is not shown.
[0041] A magnetic moving means 36 is disposed on the outer
peripheral surface of the shift sleeve 35. The magnetic moving
means 36 is constituted by an annular permanent magnet 361 that is
mounted on the outer peripheral surface of the shift sleeve 35 and
has magnetic poles in both end surfaces in the axial direction and
by a pair of moving yokes 362 and 363 disposed on the outer sides
of the permanent magnet 361 in the axial direction thereof. The
permanent magnet 361 in the illustrated embodiment is magnetized
into an N-pole in the right end surface in FIGS. 1 and 2, and is
magnetized into an S-pole in the left end surface in FIGS. 1 and 2.
The above pair of moving yokes 362 and 363 is made of a magnetic
material in an annular shape. The thus constituted magnetic moving
means 36 is positioned at its right end (in FIGS. 1 and 2) of the
one moving yoke 362 (right side in FIGS. 1 and 2) by a step 351
formed in the shift sleeve 35, and is positioned at its left end
(in FIGS. 1 and 2) of the other moving yoke 363 (left side in FIGS.
1 and 2) by a snap ring 37 fitted to the shift sleeve 35, so that
the motion in the axial direction thereof is limited. A fixed yoke
39 is disposed on the outer peripheral side of the magnetic moving
means 36 to surround the magnetic moving means 36. The fixed yoke
39 is made of a magnetic material in a cylindrical shape and is
mounted on the inner peripheral surface of the central casing 31b.
A pair of coils 40 and 41 is arranged on the inside of the fixed
yoke 39. The pair of coils 40 and 41 is wound on a bobbin 42 that
is made of a nonmagnetic material such as a synthetic resin and is
mounted on the inner peripheral surface of the fixed yoke 39. The
pair of coils 40 and 41 is connected to a power source circuit that
is not shown. The length of the coil 40 in the axial direction
nearly corresponds to a length of selection from the first select
position SP1 up to the fourth select position SP4. End walls 43 and
44 are mounted on both sides of the fixed yoke 39. On the inner
periphery of the end walls 43 and 44 are mounted sealing members 45
and 46 that come in contact with the outer peripheral surface of
the shift sleeve 35.
[0042] The select actuator 3 is constituted as described above, and
works based on a principle of a linear motor that is constituted by
the magnetic moving means 36 disposed on the shift sleeve 35 that
serves as the shift lever support member, by the fixed yoke 39 and
by the pair of coils 40 and 41. The operation will now be described
with reference to FIG. 3.
[0043] In the select actuator 3 according to the first embodiment,
there is established a magnetic circuit 368 passing through the
N-pole of permanent magnet 361, one moving yoke 362, one coil 40,
fixed yoke 39, the other coil 41, the other moving yoke 363 and
S-pole of permanent magnet 361, as shown in FIGS. 3(a) and 3(b). In
this state, when electric currents are supplied to the pair of
coils 40 and 41 in directions opposite to each other as shown in
FIG. 3(a), a thrust toward the right is produced by the permanent
magnet 361, i.e., by the shift sleeve 35, as indicated by an arrow
in FIG. 3(a) in accordance with the Fleming's left-hand rule. As
shown in FIG. 3(b), on the other hand, when the electric currents
are supplied to the pair of coils 40 and 41 in the directions just
opposite to the directions of FIG. 3a, a thrust toward the left is
produced by the permanent magnet 361, i.e., by the shift sleeve 35,
as indicated by an arrow in FIG. 3(b) in accordance with the
Fleming's left-hand rule. The magnitude of thrust produced by the
permanent magnet 361, i.e., produced by the shift sleeve 35, is
determined by the amount of electric power supplied to the pair of
coils 40 and 41.
[0044] The actuator 3 in the illustrated embodiment has a first
select position-limiting means 47 and a second select
position-limiting means 48 for limiting the position of the shift
lever 34 to the first select position SP1, second select position
SP2, third select position SP3 or fourth select position SP4 in
cooperation with the magnitude of thrust acting on the magnetic
moving means 36, i.e., acting on the shift sleeve 35. The first
select position-limiting means 47 comprises snap rings 471 and 472
fitted to right end portions (in FIGS. 1 and 2) of the central
casing 31b at a predetermined interval, a compression coil spring
473 disposed between the snap rings 471 and 472, a moving ring 474
disposed between the compression coil spring 473 and one snap ring
471, and a stopper 475 for limiting the motion of the moving ring
474 by coming in contact therewith when the moving ring 474 is
moved toward the right in FIGS. 1 and 2 by a predetermined
amount.
[0045] When in a state as shown in FIGS. 1 and 2, a current is
supplied to the pair of coils 40 and 41 at a voltage of, for
example, 2.4 V as shown in FIG. 3(a), the thus constituted first
select position-limiting means 47 so works that the magnetic moving
means 36 moves, i.e., the shift sleeve 35 moves, toward the right
in FIGS. 1 and 2, and the right end of the shift sleeve 35 in FIGS.
1 and 2 comes in contact with the moving ring 474 to be limited for
its position. In this state, the resilient force of the coil spring
473 has been set so as to be larger than the thrust that acts on
the permanent magnet 361, i.e., that acts on the shift sleeve 35.
Therefore, the shift sleeve 35 in contact with the moving ring 474
is brought into a halt at a position where the moving ring 474 is
in contact with the one snap ring 471. In this case, the shift
lever 34 constituted integratedly with the shift sleeve 35 is
brought to the second select position SP2. Next, when the current
is supplied to the pair of coils 40 and 41 at a voltage of, for
example, 4.8 V as shown in FIG. 3(a), the thrust acting on the
magnetic moving means 36, i.e., acting on the shift sleeve 35, has
been set so as to become larger than the resilient force of the
coil spring 473. Accordingly, the shift sleeve 35 that has come in
contact with the moving ring 474, then, moves toward the right in
FIGS. 1 and 2 against the resilient force of the coil spring 473,
and the moving ring 474 is brought into a halt at a position where
the moving ring 474 comes in contact with the stopper 475. At this
moment, the shift lever 34 constituted integratedly with the shift
sleeve 35 is brought to the first select position SP1.
[0046] Next, the second select position-limiting means 48 will be
described.
[0047] The second select position-limiting means 48 comprises snap
rings 481 and 482 fitted to left end portions (in FIGS. 1 and 2) of
the central casing 31b at a predetermined interval, a coil spring
483 disposed between the snap rings 481 and 482, a moving ring 484
disposed between the coil spring 483 and one snap ring 481, and a
stopper 485 for limiting the motion of the moving ring 484 by
coming in contact therewith when the moving ring 484 is moved
toward the left in FIGS. 1 and 2 by a predetermined amount.
[0048] When in a state as shown in FIGS. 1 and 2, a current is
supplied to the pair of coils 40 and 41 at a voltage of, for
example, 2.4 V as shown in FIG. 3(b), the thus constituted second
select position-limiting means 48 so works that the permanent
magnet 361 moves, i.e., the shift sleeve 35 moves, toward the left
in FIGS. 1 and 2, and the left end of the shift sleeve 35 comes in
contact with the moving ring 484 in FIGS. 1 and 2 to be limited for
its position. In this state, the resilient force of the coil spring
483 has been set so as to be larger than the thrust that acts on
the permanent magnet 361, i.e., that acts on the shift sleeve 35.
Therefore, the shift sleeve 35 in contact with the moving ring 484
is brought into a halt at a position where the moving ring 484 is
in contact with the one snap ring 481. In this case, the shift
lever 34 constituted integratedly with the shift sleeve 35 is
brought to the third select position SP3. Next, when the current is
supplied to the pair of coils 40 and 41 at a voltage of, for
example, 4.8 V as shown in FIG. 3b, the thrust acting on the
permanent magnet 361, i.e., acting on the shift sleeve 35, has been
set so as to become larger than the resilient force of the coil
spring 483. Accordingly, the shift sleeve 35 that has come in
contact with the moving ring 484, then, moves toward the left in
FIGS. 1 and 2 against the resilient force of the coil spring 483,
and the moving ring 484 is brought into a halt at a position where
the moving ring 484 comes in contact with the stopper 485. At this
moment, the shift lever 34 constituted integratedly with the shift
sleeve 35 is brought to the fourth select position SP4.
[0049] As described above, according to the illustrated embodiment
provided with the first select position-limiting means 47 and with
the second select position-limiting means 48, the shift lever 34
can be brought to a predetermined select position by controlling
the amount of electric power supplied to the pair of coils 40 and
41 without executing the position control operation.
[0050] The gear change device according to the illustrated
embodiment has a select position sensor 8 for detecting the
position of the shift sleeve 35 constituted integratedly with the
shift lever 34, i.e., for detecting the position thereof in the
direction of selection. The select position sensor 8 comprises a
potentiometer, and a rotary shaft 81 thereof is attached to an end
of a lever 82. An engaging pin 83 attached to the other end of the
lever 82 is brought into engagement with an engaging groove 352
formed in the shift sleeve 35. Therefore, as the shift sleeve 35
moves toward the right and left in FIG. 2, the lever 82 swings on
the rotary shaft 81 as a center, and the rotary shaft 81 rotates to
detect the operation position of the shift sleeve 35, i.e., to
detect the position thereof in the direction of selection. In
response to a signal from the select position sensor 8, the shift
lever 34 is brought to a desired select position by controlling the
voltage and the direction of current supplied to the coils 40 and
41 of the select actuator 3 by using a control means which is not
shown.
[0051] Further, the gear change device 2 of the illustrated
embodiment has a shift stroke position sensor 9 for detecting the
rotational position, i.e., for detecting the shift stroke position
of the control shaft 32 mounting the shift sleeve 35 constituted
integratedly with the shift lever 34. The shift stoke position
sensor 9 comprises a potentiometer with its rotary shaft 91 being
linked to the control shaft 32. When the control shaft 32 rotates,
therefore, the rotary shaft 91 rotates to detect the rotational
position, i.e., to detect the shift stroke position, of the control
shaft 32.
[0052] Next, the shift actuator constituted according to the first
embodiment of the present invention will be described with
reference chiefly to FIG. 4.
[0053] The shift actuator 5 according to the first embodiment shown
in FIG. 4 has a first electromagnetic solenoid 6 and a second
electromagnetic solenoid 7 for actuating, in the directions
opposite to each other, an operation lever 50 mounted on the
control shaft 32 disposed in the casings 31a, 31b, 31c of the
select actuator 3. The operation lever 50 has a hole 501 formed in
its base portion to be fitted to the control shaft 32. By fitting a
key 503 to a key groove 502 formed in the inner peripheral surface
of the hole 501 and to a key groove 322 formed in the outer
peripheral surface of the control shaft 32, the operation lever 50
turns integratedly with the control shaft 32. The operation lever
50 works as an operation member which is coupled to the shift lever
34 via the control shaft 32 and the shift sleeve 35, and is
disposed being inserted in an opening 311a formed in the lower
portion of the casing 31a which is on the left side in FIGS. 1 and
2.
[0054] Next, the first electromagnetic solenoid 6 will be
described.
[0055] The first electromagnetic solenoid 6 comprises a casing 61,
a fixed iron core 62 that is made of a magnetic material and is
disposed in the casing 61, an operation rod 63 that is made of a
nonmagnetic material such as a stainless steel and is disposed
being inserted in a through hole 621 formed in the central portion
of the fixed iron core 62, a moving iron core 64 that is made of a
magnetic material and is mounted on the operation rod 63 to be
allowed to approach, and separate away from, the fixed iron core
62, and an electromagnetic coil 66 that is wound on a bobbin 65
made of a nonmagnetic material such as synthetic resin and is
disposed between the casing 61 and the moving iron core 64 as well
as the fixed iron core 62. The thus constituted first
electromagnetic solenoid 6 so works that the moving iron core 64 is
attracted by the fixed iron core 62 when an electric current is
supplied to the electromagnetic coil 66. As a result, the operation
rod 63 mounting the moving iron core 64 moves toward the left in
FIG. 4 and its end acts on the operation lever 50 to turn it
clockwise on the control shaft 32 as a center. Then, the shift
lever 34 constituted integratedly with the shift sleeve 35 mounted
on the control shaft 32 undergoes a shifting operation in one
direction.
[0056] Next, the second electromagnetic solenoid 7 will be
described.
[0057] The second electromagnetic solenoid 7 is disposed opposite
the first electromagnetic solenoid 6. Like the first
electromagnetic solenoid 6, the second electromagnetic solenoid 7,
too, comprises a casing 71, a fixed iron core 72 that is made of a
magnetic material and is disposed in the casing 71, an operation
rod 73 that is made of a nonmagnetic material such as a stainless
steel and is disposed being inserted in a through hole 721 formed
in the central portion of the fixed iron core 72, a moving iron
core 74 that is made of a magnetic material and is mounted on the
operation rod 73 to be allowed to approach, and separate away from,
the fixed iron core 72, and an electromagnetic coil 76 that is
wound on a bobbin 75 made of a nonmagnetic material such as
synthetic resin and is disposed between the casing 71 and the
moving iron core 74 as well as the fixed iron core 72. The thus
constituted second electromagnetic solenoid 7 so works that the
moving iron core 74 is attracted by the fixed iron core 72 when an
electric current is supplied to the electromagnetic coil 76. As a
result, the operation rod 73 mounting the moving iron core 74 moves
toward the right in FIG. 4 and its end acts on the operation lever
50 to turn it counterclockwise on the control shaft 32 as a center.
Then, the shift lever 34 constituted integratedly with the shift
sleeve 35 mounted on the control shaft 32 undergoes a shifting
operation in the other direction.
[0058] As described above, the shift actuator 5 according to the
first embodiment has the first electromagnetic solenoid and the
second electromagnetic solenoid for actuating the operation lever
50 (operation member) coupled to the shift lever 34 in the
directions opposite to each other. Therefore, the shift actuator
features improved durability since it has no rotary mechanism and
features a compact constitution and an increased operation speed
since it needs no speed reduction mechanism constituted by a
ball-screw mechanism or a gear mechanism that is employed by the
actuator that uses an electric motor.
[0059] Next, the shift actuator constituted according to a second
embodiment of the present invention will be described with
reference to FIG. 5. In the shift actuator 5a according to the
second embodiment shown in FIG. 5, the members same as those of the
first embodiment shown in FIG. 4 are denoted by the same reference
numerals and their description is not repeated.
[0060] The shift actuator 5 of the first embodiment shown in FIG. 4
is of the pushing type. The shift actuator 5a of the second
embodiment shown in FIG. 5, however, is of the pulling type. That
is, the shift actuator 5a according to the second embodiment has a
first electromagnetic solenoid 6a and a second electromagnetic
solenoid 7a for actuating, in the directions opposite to each
other, the operation lever 50 mounted on the control shaft 32. The
first electromagnetic solenoid 6a comprises a casing 61a, a fixed
iron core 62a that is made of a magnetic material and is disposed
in the casing 61a, a moving iron core 64a made of a magnetic
material and is disposed to be allowed to approach, and separate
away from, the fixed iron core 62a, an electromagnetic coil 66a
that is wound on a bobbin 65a made of a nonmagnetic material such
as synthetic resin and is disposed between the casing 61a and the
moving iron core 64a as well as the fixed iron core 62a, and a
cylindrical slide guide 67a that is made of a suitable synthetic
resin and is disposed on the inside of the bobbin 65a to guide the
motion of the moving iron core 64a.
[0061] The second electromagnetic solenoid 7a is disposed opposite
the first electromagnetic solenoid 6a. Like the first
electromagnetic solenoid 6a, the second electromagnetic solenoid
7a, too, comprises a casing 71a, a fixed iron core 72a that is made
of a magnetic material and is disposed in the casing 71a, a moving
iron core 74a that is made of a magnetic material and is disposed
to be allowed to approach, and separate away from, the fixed iron
core 72a, an electromagnetic coil 76a that is wound on a bobbin 75a
made of a nonmagnetic material such as synthetic resin and is
disposed between the casing 71a and the moving iron core 74a as
well as the fixed iron core 72a, and a cylindrical slide guide 77a
that is made of a suitable synthetic resin and is disposed on the
inside of the bobbin 75a to guide the motion of the moving iron
core 74a. In the shift actuator 5a of the second embodiment, the
moving iron core 64a of the first electromagnetic solenoid 6a and
the moving iron core 74a of the second electromagnetic solenoid 7a
are coupled together by an operation rod 78a. A groove is formed in
the central portion of the operation rod 78a, and an end of the
operation lever 50 comes into engagement with the groove 781a.
[0062] The shift actuator 5a according to the second embodiment is
constituted as described above. The operation will now be described
below.
[0063] When an electric current is supplied to the electromagnetic
coil 76a of the second electromagnetic solenoid 7a, the moving iron
core 74a is attracted by the fixed iron core 72a. As a result, the
operation rod 78a coupled to the moving iron core 74a moves toward
the left in FIG. 5, causing the control shaft 32 to turn clockwise
via the operation lever 50 of which the end is fitted to the groove
781a formed in the central portion of the operation rod 78a.
Therefore, the shift lever 34 constituted integratedly with the
shift sleeve 35 mounted on the control shaft 32, is shifted in one
direction. Further, when the electric current is supplied to the
electromagnetic coil 66a of the first electromagnetic solenoid 6a,
the moving iron core 64a is attracted by the fixed iron core 62a.
As a result, the operation rod 78a coupled to the moving iron core
64a moves toward the right in FIG. 5, causing the control shaft 32
to turn counterclockwise via the operation lever 50 of which the
end is fitted to the groove 781a formed in the central portion of
the operation rod 78a. Therefore, the shift lever 34 constituted
integratedly with the shift sleeve 35 mounted on the control shaft
32, is shifted in the other direction.
[0064] Next, the shift actuator constituted according to a third
embodiment of the present invention will be described with
reference to FIG. 6. In the shift actuator 5b according to the
third embodiment shown in FIG. 6, the members same as those of the
first embodiment shown in FIG. 3 are denoted by the same reference
numerals and their description is not repeated.
[0065] The shift actuator 5b, too, of the third embodiment shown in
FIG. 6 has, like that of the first embodiment, a first
electromagnetic solenoid 6b and a second electromagnetic solenoid
7b for actuating the operation lever 50 mounted on the control
shaft 32 that is disposed in the casings 31a, 31b and 31c of the
select actuator 3. The first electromagnetic solenoid 6b and the
second electromagnetic solenoid 7b of the third embodiment are
different from the first electromagnetic solenoid 6 and the second
electromagnetic solenoid 7 of the first embodiment in regard to the
shapes of the opposing end surfaces of the fixed iron cores and of
the moving iron cores. That is, the first electromagnetic solenoid
6b and the second electromagnetic solenoid 7b of the third
embodiment have a feature in that stepped protuberances 621b and
721b are respectively formed at the centers of the end surfaces of
the fixed cores 62b and 72b opposed to the moving iron cores 64b
and 74b, and that stepped recesses 641b and 741b are respectively
formed in the centers of the end surfaces of the moving iron cores
64b and 74b opposed to the fixed iron cores 62b and 72b, the
recesses 641b and 741b being corresponded to the protuberances 621b
and 721b. The positions where the edges 622b, 722b of the
protuberances 621b, 721b of the fixed iron cores 62b, 72b become
closest to edges 642b and 742b of the recesses 641b, 741b of the
moving iron cores 64b, 74b are so constituted as to correspond to
the synchronizing positions of the synchronizing device as will be
described later. The embodiment shown in FIG. 6 has dealt with a
case where the stepped protuberances 621b and 721b are formed on
the fixed iron cores 62b and 72b, and the stepped recesses 641b and
741b are formed in the moving iron cores 64b and 74b. It is,
however, also allowable to form the stepped protuberances on the
moving iron cores 64b and 74b, and to form the stepped recesses in
the fixed iron cores 62b and 72b.
[0066] The shift actuator 5b according to the third embodiment is
constituted as described above. Described below with reference to
FIGS. 7, 8 and 10 are a relationship between the operation
positions of the first electromagnetic solenoid 6b and of the
second electromagnetic solenoid 7b and the corresponding shift
stroke positions of the synchronizing device with which the
transmission (not shown) is furnished, as well as the thrusts at
the operation positions of the first electromagnetic solenoid 6b
and of the second electromagnetic solenoid 7b.
[0067] FIG. 7 illustrates the operation states of the first
electromagnetic solenoid 6b and of the second electromagnetic
solenoid 7b. In FIG. 7, FIG. 7(a) illustrates a state where the
synchronizing device is brought to a neutral position, FIG. 7(b)
illustrates a state where the synchronizing device is brought to a
synchronizing position by the first electromagnetic solenoid 6b,
FIG. 7(c) illustrates a state where the synchronizing device is
brought to a gear-engaging position by the first electromagnetic
solenoid 6b, FIG. 7(d) illustrates a state where the synchronizing
device is brought to a synchronizing position by the second
electromagnetic solenoid 7b, and FIG. 7(e) illustrates a state
where the synchronizing device is brought to a gear-engaging
position by the second electromagnetic solenoid 7b.
[0068] FIG. 8 illustrates a relationship among the spline 11 of the
clutch sleeve, teeth 12a, 12b of the synchronizer rings, and dog
teeth 13a, 13b. In FIG. 8, FIG. 8(a) illustrates a neutral state,
FIG. 8(b) illustrates a synchronized state of when the first
electromagnetic solenoid 6b is operated, FIG. 8(c) illustrates a
gear-engaged state of when the first electromagnetic solenoid 6b is
operated, FIG. 8(d) illustrates a synchronized state of when the
second electromagnetic solenoid 7b is operated, and FIG. 8(e)
illustrates a gear-engaged state of when the second electromagnetic
solenoid 7b is operated.
[0069] FIG. 10 is a diagram illustrating a relationship between the
thrusts and the operation positions of operation rods 63 and 73 of
the first electromagnetic solenoid 6b and of the second
electromagnetic solenoid 7b. In FIGS. 10(a) and 10(b), the
operation position P0 of the electromagnetic solenoid shows a state
where the first electromagnetic solenoid 6b and the second
electromagnetic solenoid 7b are in the neutral state shown in FIG.
7(a), PR2 shows a state where the first electromagnetic solenoid 6b
and the second electromagnetic solenoid 7b are at the gear-engaging
position shown in FIG. 7(e), and PL2 shows a state where the first
electromagnetic solenoid 6b and the second electromagnetic solenoid
7b are at the gear-engaging position shown in FIG. 7(c). FIG. 10(a)
is a graph illustrating the thrust at each of the operation
positions of when the first electromagnetic solenoid 6b is
energized to be operated from a state where the first
electromagnetic solenoid 6b and the second electromagnetic solenoid
7b are in the gear-engaged state PR2 shown in FIG. 7(e) up to the
gear-engaging position PL2 shown in FIG. 7(c). FIG. 10(b) is a
graph illustrating the thrust at each of the operation positions of
when the second electromagnetic solenoid 7b is energized to be
operated from a state where the first electromagnetic solenoid 6b
and the second electromagnetic solenoid 7b are in the gear-engaged
state PL2 shown in FIG. 7(c) up to the gear-engaging position PR2
shown in FIG. 7(e).
[0070] First, described below with reference to FIG. 10(a) is the
thrust at each of the operation positions (graph indicated by a
solid line) of when the first electromagnetic solenoid 6b is
energized to be operated from a state where the first
electromagnetic solenoid 6b and the second electromagnetic solenoid
7b are in the gear-engaged state PR2 shown in FIG. 7(e) up to the
gear-engaging position PL2 shown in FIG. 7(c). When an electric
current is supplied to the electromagnetic coil 66 of the first
electromagnetic solenoid 6b in the gear-engaged state shown in FIG.
7(e) (i.e., gear-engaged state shown in FIG. 8(e) in the case of
the synchronizing device), the moving iron core 64b is attracted by
the fixed iron core 62b to produce a thrust on the operation rod
63. At the gear-engaging position PR2 (stroke start position),
however, the thrust is small since the gap is large between the
moving iron core 64b and the fixed iron core 62b. The thrust
increases as the moving iron core 64b moves toward the fixed iron
core 62b. As the neutral position represented by PO in FIG. 10(a)
is passed, i.e., as the neutral state shown in FIG. 7(a) is passed
(as the neutral state shown in FIG. 8(a) is passed in the case of
the synchronizing device), the edge 642b of the recess 641b of the
moving iron core 64b approaches the edge 622b of the protuberance
621b of the fixed iron core 62b. At the synchronizing position
represented by PL1 in FIG. 10(a), i.e., in the synchronized state
shown in FIG. 7(b) (in the synchronized state shown in FIG. 8(b) in
the case of the synchronizing device), the two edges most approach
each other. In the synchronized state shown in FIG. 7(b), the
thrust increases since the magnetic flux density increases at the
two edges. When the synchronized position represented by PL1 in
FIG. 10(a) is passed, there is established a state where the recess
621b of the moving iron core 64b fits to the protuberance 641b of
the fixed iron core 62b. Therefore, the thrust decreases since the
magnetic flux acts in the radial direction at the fitting portion.
As the moving iron core 64b further approaches the fixed iron core
62b, the thrust sharply increases and arrives at the gear-engaging
position (end of stroke) represented by PL2 in FIG. 10(a), i.e.,
arrives at the gear-engaged state shown in FIG. 7(c) (gear-engaged
state shown in FIG. 8(c) in the case of the synchronizing
device).
[0071] Next, described below with reference to FIG. 10(b) is the
thrust at each of the operation positions (graph indicated by a
solid line) of when the second electromagnetic solenoid 7b is
energized to be operated from a state where the first
electromagnetic solenoid 6b and the second electromagnetic solenoid
7b are in the gear-engaged state PL2 shown in FIG. 7(c) up to the
gear-engaging position PR2 shown in FIG. 7(e). When an electric
current is supplied to the electromagnetic coil 76 of the second
electromagnetic solenoid 7b in the gear-engaged state shown in FIG.
7(c) (i.e., gear-engaged state shown in FIG. 8(c) in the case of
the synchronizing device), the moving iron core 74b is attracted by
the fixed iron core 72b to produce a thrust on the operation rod
73. At the gear-engaging position PL2 (stroke start position),
however, the thrust is small since the gap is large between the
moving iron core 74b and the fixed iron core 72b. The thrust
increases as the moving iron core 74b moves toward the fixed iron
core 72b. As the neutral position represented by P0 in FIG. 10(b)
is passed, i.e., as the neutral state shown in FIG. 7(a) is passed
(as the neutral state shown in FIG. 8(a) is passed in the case of
the synchronizing device), the edge 742b of the recess 741b of the
moving iron core 74b approaches the edge 722b of the protuberance
721b of the fixed iron core 72b. At the synchronizing position
represented by PR1 in FIG. 10(b), i.e., in the synchronized state
shown in FIG. 7(d) (in the synchronized state shown in FIG. 8(d) in
the case of the synchronizing device), the two edges most approach
each other. In the synchronized state shown in FIG. 7(d), the
thrust increases since the magnetic flux density increases at the
two edges. When the synchronized position represented by PR1 in
FIG. 10(b) is passed, there is established a state where the recess
721b of the moving iron core 74b fits to the protuberance 741b of
the fixed iron core 72b. Therefore, the thrust decreases since the
magnetic flux acts in the radial direction at the fitting portion.
As the moving iron core 74b further approaches the fixed iron core
72b, the thrust sharply increases and arrives at the gear-engaging
position (end of stroke) represented by PR2 in FIG. 10(b), i.e.,
arrives at the gear-engaged state shown in FIG. 7(e) (gear-engaged
state shown in FIG. 8(e) in the case of the synchronizing
device).
[0072] As described above, the shift actuator 5b comprising the
first electromagnetic solenoid 6b and the second electromagnetic
solenoid 7b according to the third embodiment has such
characteristics that the thrust once swells at the synchronizing
positions (PL1, PR1) of the synchronizing device. Namely, a
predetermined thrust is obtained at the synchronizing position
where the operation force is required, making it possible to use
the electromagnetic solenoids of a small size. In FIGS. 10(a) and
10(b), broken lines show thrust characteristics of when the shift
actuator 5 in the above-mentioned first embodiment has a size same
as that of the shift actuator 5b in the above-mentioned third
embodiment, from which it is learned that the thrust is small at
the synchronizing positions (PL1, PR1) when compared to the thrust
characteristics of the shift actuator 5b of the third embodiment
indicated by the solid lines. In order for the shift actuator 5 of
the first embodiment to produce the thrust at the synchronizing
positions (PL1, PR1) comparable to that of the shift actuator 5b of
the third embodiment, the shift actuator 5 of the first embodiment
must use the electromagnetic solenoids of a large size. The shift
actuator 5b of the third embodiment, on the other hand, can employ
the electromagnetic solenoids of a small size. Further, the shift
actuator 5b according to the third embodiment produces, at the end
of the stroke, a thrust which is smaller than that of the shift
actuator 5 of the first embodiment and hence, produces a decreased
impact at the end of the stroke. The third embodiment shown in FIG.
6 has dealt with the case where the invention was applied to the
push-type actuator corresponding to that of the first embodiment.
However, the same action and effect are also obtained even by
applying the present invention to the pull-type actuator of the
second embodiment.
[0073] Next, a fourth embodiment of the shift actuator constituted
according to the present invention will be described with reference
to FIG. 9. In the shift actuator 5c of the fourth embodiment shown
in FIG. 9, the same members as those of the third embodiment shown
in FIG. 6 are denoted by the same reference numerals but are not
described again in detail.
[0074] According to the shift actuator 5c of the fourth embodiment,
the stepped protuberances 621c, 721c formed at the centers on the
end surfaces of the fixed iron cores 62c, 72c constituting the
first electromagnetic solenoid 6c and the second electromagnetic
solenoid 7c as well as the stepped recesses 641c, 741c
corresponding to the protuberances 621c, 721c formed at the centers
on the end surfaces of the fixed iron cores 62c, 72c, have shapes
different from the shapes of the stepped protuberances 621b, 721b
of the actuator 5b and of the stepped recesses 641b, 741b of the
third embodiment shown in FIG. 6. That is, the outer peripheral
surfaces of the protuberances 621b, 721b and the inner peripheral
surfaces of the recesses 641b, 741b, have the same diameters over
the full length in the third embodiment. In the shift actuator 5c
according to the fourth embodiment shown in FIG. 9, on the other
hand, the outer peripheral surfaces of the protuberances 621c, 721c
and the inner peripheral surfaces of the recesses 641c, 741c are
tapered. The thus constituted shift actuator 5c exhibits
intermediate thrust characteristics as indicated by dot-and-dash
chain lines in FIGS. 10(a) and 10(b) lying between the thrust
characteristics of the shift actuator 5b of the third embodiment
indicated by the solid lines and the thrust characteristics of the
actuator 5 of the first embodiment indicated by the broke lines.
The thrust characteristics approach those indicated by the solid
lines when the outer peripheral surfaces of the protuberances 621c,
721c and the outer peripheral surfaces of the recesses 641c, 741c
have a small tapered angle, and approach those indicated by the
broken lines when the outer peripheral surfaces of the
protuberances 621c, 721c and the outer peripheral surfaces of the
recesses 641c, 741c have a large tapered angle.
[0075] Next, a fifth embodiment of the shift actuator constituted
according to the present invention will be described with reference
to FIGS. 11 and 12. In the shift actuator 5d of the fifth
embodiment shown in FIGS. 11 and 13, the same members as those of
the first embodiment shown in FIG. 4 are denoted by the same
reference numerals but are not described again in detail.
[0076] The shift actuator 5d according to the fifth embodiment has
features as described below. That is, in the fixed iron core 62 and
the moving iron core 64 constituting the first electromagnetic
solenoid 6d, the opposing areas of the outer peripheral surface 640
of the moving iron core 64 and the inner peripheral surface 610 of
the casing 61 that works as the fixed yoke are so constituted as to
decrease, at a position where the attraction ends shown in FIG.
12(a) after the moving iron core 64 is attracted by the fixed iron
core 62 as a result of supplying the current to the electromagnetic
coil 66. In the illustrated embodiment, the outer peripheral
surface 640 of the moving iron core 64 is opposed to the entire
inner peripheral surface 610 of the casing 61 that works as the
fixed yoke when the shift actuator 5a is in the neutral state shown
in FIG. 11 and when the shift actuator 5a is operated by the second
electromagnetic solenoid 7d as will be described later with
reference to FIG. 12(b). In the illustrated embodiment, further,
the opposing area is so constituted as to become zero (0) between
the outer peripheral surface 640 of the moving iron core 64 and the
inner peripheral surface 610 of the casing 61 working as the fixed
yoke, at a position where attraction ends shown in FIG. 12(a) after
the moving iron core 64 is attracted by the fixed iron core 62.
[0077] Further, in the fixed iron core 72 and the moving iron core
74 constituting the second electromagnetic solenoid 7d, the
opposing areas of the outer peripheral surface 740 of the moving
iron core 74 and the inner peripheral surface 710 of the casing 71
working as the fixed yoke are so constituted as to decrease, at a
position where the attraction ends shown in FIG. 12(b) after the
moving iron core 74 is attracted by the fixed iron core 72 as a
result of supplying the current to the electromagnetic coil 76. In
the illustrated embodiment, the outer peripheral surface 740 of the
moving iron core 74 is entirely opposed to the inner peripheral
surface 710 of the casing 71 that works as the fixed yoke when the
shift actuator 5 is in the neutral state shown in FIG. 11 and when
the shift actuator 5 is operated by the first electromagnetic
solenoid 6 as shown in FIG. 12(a). In the illustrated embodiment,
further, the opposing area is constituted as to become zero (0)
between the outer peripheral surface 740 of the moving iron core 74
and the inner peripheral surface 710 of the casing 71 working as
the fixed yoke, at a position where attraction ends shown in FIG.
12(b) after the moving iron core 74 is attracted by the fixed iron
core 72.
[0078] The shift actuator 5d according to the fifth embodiment is
constituted as described above. Described below with reference to
FIGS. 8, 13 and 19 are a relationship between the operation
positions of the first electromagnetic solenoid 6d and of the
second electromagnetic solenoid 7d and the corresponding shift
stroke positions of the synchronizing device with which the
transmission (not shown) is furnished, as well as the thrusts at
the operation positions of the first electromagnetic solenoid 6 and
of the second electromagnetic solenoid 7.
[0079] FIG. 13 illustrates the operation states of the first
electromagnetic solenoid 6d and of the second electromagnetic
solenoid 7d. In FIG. 13, FIG. 13(a) illustrates a state where the
synchronizing device is brought to a neutral position, FIG. 13(b)
illustrates a state where the synchronizing device is brought to a
synchronizing position by the first electromagnetic solenoid 6d,
FIG. 13(c) illustrates a state where the synchronizing device is
brought to a gear-engaging position by the first electromagnetic
solenoid 6d, FIG. 13(d) illustrates a state where the synchronizing
device is brought to a synchronizing position by the second
electromagnetic solenoid 7d, and FIG. 13(e) illustrates a state
where the synchronizing device is brought to a gear-engaging
position by the second electromagnetic solenoid 7d.
[0080] FIG. 19 is a diagram illustrating a relationship between the
thrusts and the operation positions of operation rods 63 and 73 of
the first electromagnetic solenoid 6d and of the second
electromagnetic solenoid 7d. In FIGS. 19(a) and 19(b), the
operation position P0 of the electromagnetic solenoid shows a state
where the first electromagnetic solenoid 6d and the second
electromagnetic solenoid 7d are in the neutral state shown in FIG.
13(a), PR2 shows a state where the first electromagnetic solenoid
6d and the second electromagnetic solenoid 7d are at the
gear-engaging position shown in FIG. 13(e), and PL2 shows a state
where the first electromagnetic solenoid 6d and the second
electromagnetic solenoid 7d are at the gear-engaging position shown
in FIG. 13(c). FIG. 19(a) is a graph illustrating the thrust at
each of the operation positions of when the first electromagnetic
solenoid 6d is energized to be operated from a state where the
first electromagnetic solenoid 6d and the second electromagnetic
solenoid 7d are in the gear-engaged state PR2 shown in FIG. 13(e)
up to the gear-engaging position PL2 shown in FIG. 13(c). FIG.
19(b) is a graph illustrating the thrust at each of the operation
positions of when the second electromagnetic solenoid 7d is
energized to be operated from a state where the first
electromagnetic solenoid 6d and the second electromagnetic solenoid
7d are in the gear-engaged state PL2 shown in FIG. 13(c) up to the
gear-engaging position PR2 shown in FIG. 13(e). In FIGS. 19(a) and
19(b), the solid lines indicate thrust characteristics of the first
electromagnetic solenoid 6d and of the second electromagnetic
solenoid 7d constituting the shift actuator 5d of the fifth
embodiment, and the broken lines indicate thrust characteristics of
when the conventionally employed electromagnetic solenoids are
applied to the shift actuator.
[0081] First, described below with reference to FIG. 19(a) is the
thrust at each of the operation positions (graph indicated by the
solid line) of when the first electromagnetic solenoid 6d is
energized to be operated from a state where the first
electromagnetic solenoid 6d and the second electromagnetic solenoid
7d are in the gear-engaged state PR2 shown in FIG. 8(e) up to the
gear-engaging position PL2 shown in FIG. 8(c). The thrust
characteristics of when the conventionally used electromagnetic
solenoids are applied to the shift actuator are such that the
thrust sharply increases as indicated by the broken line as the
operation position approaches the end of the stroke (PL2) from the
position where the stroke starts (PR2) (as the moving iron core
approaches the fixed iron core).
[0082] In the shift actuator 5d of the fifth embodiment, when an
electric current is supplied to the electromagnetic coil 66 of the
first electromagnetic solenoid 6d in the gear-engaged state shown
in FIG. 13(e) (gear-engaged state shown in FIG. 8(e) in the case of
the synchronizing device), the moving iron core 64 is attracted by
the fixed iron core 62 to produce a thrust on the operation rod 63.
At the gear-engaging position PR2 (stroke start position), however,
the thrust is small since the gap is large between the moving iron
core 64 and the fixed iron core 62. The thrust increases as the
moving iron core 64 moves toward the fixed iron core 62. The thrust
increases, like that of the conventional counterpart as indicated
by the broken line, until the synchronized state represented by PL1
in FIG. 20(a) is reached, i.e., until the synchronized state shown
in FIG. 13(b) is reached (until the synchronized state shown in
FIG. 8(b) is reached in the case of the synchronizing device) past
the neutral position represented by P0 in FIG. 19(a), i.e., past
the neutral state shown in FIG. 13(a) (past the neutral state shown
in FIG. 8(a) in the case of the synchronizing device). In the shift
actuator 5d according to the fifth embodiment, the right end of the
outer peripheral surface 640 of the moving iron core 64 comes into
agreement with the right end of the inner peripheral surface 610 of
the casing 61 that works as a fixed yoke at the synchronizing
position PL1, as shown in FIG. 13(b).
[0083] As the moving iron core 64 moves toward the fixed iron core
62 from the synchronized state shown in FIGS. 13(b) and 8(b), the
opposing areas decrease between the outer peripheral surface 640 of
the moving iron core 64 and the inner peripheral surface 610 of the
casing 61 working as the fixed yoke. As a result, reluctance
increases between the casing 61 working as the fixed yoke and the
moving iron core 64, and the magnetic flux density decreases in the
attraction portion (opposing surfaces of the fixed iron core 62 and
of the moving iron core 64). Therefore, though the gap between the
moving iron core 64 and the fixed iron core 62 becomes small after
having passed the synchronizing position PL1, the thrust of the
first electromagnetic solenoid 6d does not sharply increase and
arrives at the gear-engaging position (end of stroke) represented
by PL2, i.e., arrives at the gear-engaged state shown in FIG. 13(c)
(gear-engaged state shown in FIG. 8(c) in the case of the
synchronizing device) at a relatively smaller value compared with
that of the broken line of the prior art, as shown in FIG.
19(a).
[0084] Next, described below with reference to FIG. 19(b) is the
thrust at each of the operation positions (graph indicated by the
solid line) of when the second electromagnetic solenoid 7d is
energized to be operated from a state where the first
electromagnetic solenoid 6d and the second electromagnetic solenoid
7d are in the gear-engaged state PL2 shown in FIG. 13(c) up to the
gear-engaging position PR2 shown in FIG. 13(e). When an electric
current is supplied to the electromagnetic coil 76 of the second
electromagnetic solenoid 7d in the gear-engaged state shown in FIG.
13(c) (gear-engaged state shown in FIG. 8(c) in the case of the
synchronizing device), the moving iron core 74 is attracted by the
fixed iron core 72 to produce a thrust on the operation rod 73. At
the gear-engaging position PL2 (stroke start position), however,
the thrust is small since the gap is large between the moving iron
core 74 and the fixed iron core 72. The thrust increases as the
moving iron core 74 moves toward the fixed iron core 72. The thrust
increases, like that of the conventional counterpart as indicated
by the broken line, until the synchronizing state represented by
PL1 in FIG. 19(b) is reached, i.e., until the synchronized state
shown in FIG. 13(d) is reached (until the synchronized state shown
in FIG. 8(d) is reached in the case of the synchronizing device)
past the neutral position represented by P0 in FIG. 19(b), i.e.,
past the neutral state shown in FIG. 13(a) (past the neutral state
shown in FIG. 8(a) in the case of the synchronizing device). In the
shift actuator 5d according to the fifth embodiment, the left end
of the outer peripheral surface 740 of the moving iron core 74
comes into agreement with the left end of the inner peripheral
surface 710 of the casing 71 that works as a fixed yoke at the
synchronizing position PL1, as shown in FIG. 13(d).
[0085] As the moving iron core 74 moves toward the fixed iron core
72 from the synchronized state shown in FIGS. 13(d) and 8(d), the
opposing areas decrease between the outer peripheral surface 740 of
the moving iron core 74 and the inner peripheral surface 710 of the
casing 71 working as the fixed yoke. As a result, reluctance
increases between the casing 71 working as the fixed yoke and the
moving iron core 74, and the magnetic flux density decreases in the
attraction portion (opposing surfaces of the fixed iron core 72 and
of the moving iron core 67). Therefore, though the gap between the
moving iron core 74 and the fixed iron core 72 becomes small after
having passed the synchronizing position PL1, the thrust of the
first electromagnetic solenoid 7d does not sharply increase and
arrives at the gear-engaging position (end of stroke) represented
by PR2, i.e., arrives at the gear-engaged state shown in FIG. 13(e)
(gear-engaged state shown in FIG. 8(e) in the case of the
synchronizing device) at a relatively smaller value compared with
that of the broken line of the prior art, as shown in FIG.
19(b).
[0086] As described above, the shift actuator 5d according to the
fifth embodiment comprises the first electromagnetic solenoid 6d
and the second electromagnetic solenoid 7d for actuating the
operation lever 50 (operation member) coupled to the shift lever 34
in the directions opposite to each other. Therefore, the shift
actuator features improved durability since it has no rotary
mechanism and features a compact constitution and an increased
operation speed since it needs no speed reduction mechanism
constituted by a ball-screw mechanism or a gear mechanism that is
employed by the actuator that uses an electric motor. Further, the
shift actuator 5d according to the fifth embodiment is so
constituted that opposing areas of the outer peripheral surface 640
or 740 of the moving iron core 64 or 74 and the inner peripheral
surface 610 or 710 of the casing 61 or 71 working as a fixed yoke
decrease, at a position where the attraction ends as shown in FIGS.
12(a) and 12(b). Therefore, the reluctance increases between the
casing 61 or 71 that works as the fixed yoke and the moving iron
core 64 or 74, and the magnetic flux density decreases in the
attraction portion, enabling the thrust to be decreased at the end
of the stroke of the first electromagnetic solenoid 6d or the
second electromagnetic solenoid 7d. It is therefore allowed to
soften the impact on the moving iron cores 64, 74 and on the clutch
sleeves of the synchronizing device at the end of the stroke.
[0087] Next, the shift actuator constituted according to a sixth
embodiment of the present invention will be described with
reference to FIGS. 14 and 15. In the shift actuator 5e according to
the sixth embodiment shown in FIGS. 14 and 15, the members same as
those of the above-mentioned embodiments are denoted by the same
reference numerals and their description is not repeated.
[0088] The shift actuators of the fifth embodiment are of the
pushing type. The shift actuator 5e of the sixth embodiment shown
in FIGS. 14 and 15, however, is of the pulling type. That is, the
shift actuator 5e according to the sixth embodiment has a first
electromagnetic solenoid 6e and a second electromagnetic solenoid
7e for actuating, in the directions opposite to each other, the
operation lever 50 mounted on the control shaft 32. The first
electromagnetic solenoid 6e comprises a casing 61e, an
electromagnetic coil 66e wound on a bobbin 65e that is disposed in
the casing 61e and is made of a nonmagnetic material such as a
synthetic resin, a fixed iron core 62e disposed in the
electromagnetic coil 66e, a moving iron core 64e that is made of a
magnetic material and is disposed to be allowed to approach, and
separate away from, the fixed iron core 62e, and a cylindrical
slide guide 67e that is made of a suitable synthetic resin and is
disposed on the inside of the bobbin 65e to guide the motion of the
moving iron core 64e. In the illustrated embodiment, the casing 61e
is made of the magnetic material, has an inner peripheral surface
610e opposed to the outer peripheral surface 640e of the moving
iron core 64e, and is constituted to work as a fixed yoke.
[0089] The second electromagnetic solenoid 7e is disposed opposed
to the first electromagnetic solenoid 6e. Like the first
electromagnetic solenoid 6e, the second electromagnetic solenoid
7e, too, comprises a casing 71e, an electromagnetic coil 76e wound
on a bobbin 75e that is disposed in the casing 71e and is made of a
nonmagnetic material such as a synthetic resin, a fixed iron core
72e disposed in the electromagnetic coil 76e, a moving iron core
74e that is made of a magnetic material and is disposed to be
allowed to approach, and separate away from, the fixed iron core
72e, and a cylindrical slide guide 77e that is made of a suitable
synthetic resin and is disposed on the inside of the bobbin 75e to
guide the motion of the moving iron core 74e. Like the casing 61e,
the casing 71e, too, is made of the magnetic material, has an inner
peripheral surface 710e opposed to the outer peripheral surface
740e of the moving iron core 74e, and works as a fixed yoke. In the
shift actuator 5e of the sixth embodiment, the moving iron core 64e
of the first electromagnetic solenoid 6e and the moving iron core
74e of the second electromagnetic solenoid 7e are coupled together
by an operation rod 78e. A groove 781e is formed in the central
portion of the operation rod 78e, and an end of the operation lever
50 is brought into engagement with the groove 781e.
[0090] The shift actuator 5e according to the sixth embodiment is
constituted as described above. The operation will now be described
below.
[0091] When an electric current is supplied to the electromagnetic
coil 76e of the second electromagnetic solenoid 7e, the moving iron
core 74e is attracted by the fixed iron core 72e as shown in FIG.
15(a). As a result, the operation rod 78e coupled to the moving
iron core 74e moves toward the left in FIG. 15, causing the control
shaft 32 to turn clockwise via the operation lever 50 of which the
end is fitted to the groove 781e formed in the central portion of
the operation rod 78e. Therefore, the shift lever 34 constituted
integratedly with the shift sleeve 35 mounted on the control shaft
32, is shifted in one direction. Here, the areas opposing to each
other of the fixed iron core 72e and the moving iron core 74e are
so constituted as to decrease, at a position where the attraction
ends shown in FIG. 15(a) after the moving iron core 74e is
attracted by the fixed iron core 72e as a result of supplying a
current to the electromagnetic coil 76e. In the illustrated
embodiment, the outer peripheral surface 740e of the moving iron
core 74e is opposed to the entire inner peripheral surface 710e of
the casing 71e that works as the fixed yoke when the shift actuator
5e is in the neutral state shown in FIG. 14 and when the shift
actuator 5e is operated by the first electromagnetic solenoid 6e as
will be described later with reference to FIG. 15(b). In the
illustrated embodiment, further, the opposing area is so
constituted as to become zero (0) between the outer peripheral
surface 740e of the moving iron core 74e and the inner peripheral
surface 710e of the casing 71e working as the fixed yoke, at a
position where attraction ends shown in FIG. 15(a) after the moving
iron core 74e is attracted by the fixed iron core 72e.
[0092] Further, when the electric current is supplied to the
electromagnetic coil 66e of the first electromagnetic solenoid 6e,
the moving iron core 64e is attracted by the fixed iron core 62e.
As a result, the operation rod 78e coupled to the moving iron core
64e moves toward the right in FIG. 14, causing the control shaft 32
to turn counterclockwise via the operation lever 50 of which the
end is fitted to the groove 781a formed in the central portion of
the operation rod 78a. Therefore, the shift lever 34 constituted
integratedly with the shift sleeve 35 mounted on the control shaft
32, is shifted in the other direction. Here, the areas opposing to
each other of the fixed iron core 62e and the moving iron core 64e
are so constituted as to decrease, at a position where the
attraction ends shown in FIG. 15(b) after the moving iron core 64e
is attracted by the fixed iron core 62e as a result of supplying a
current to the electromagnetic coil 66e. In the illustrated
embodiment, the outer peripheral surface 640e of the moving iron
core 64e is opposed to the entire inner peripheral surface 610e of
the casing 61e that works as the fixed yoke when the shift actuator
5e is in the neutral state shown in FIG. 14 and when the shift
actuator 5e is operated by the second electromagnetic solenoid 7e
as shown in FIG. 15(a). In the illustrated embodiment, further, the
opposing area is so constituted as to become zero (0) between the
outer peripheral surface 640e of the moving iron core 64e and the
inner peripheral surface 610e of the casing 61e working as the
fixed yoke, at a position where attraction ends shown in FIG. 15(b)
after the moving iron core 64e is attracted by the fixed iron core
62e.
[0093] Like the shift actuator 5d of the fifth embodiment as
described above, the shift actuator 5e according to the sixth
embodiment is so constituted that opposing areas of the outer
peripheral surface 740e or 640e of the moving iron core 74e or 64e
and the inner peripheral surface 710e or 610e of the casing 71d or
61e working as a fixed yoke decrease, at a position where the
attraction ends, as shown in FIGS. 15(a) and 15(b). Therefore, the
reluctance increases between the casing 71e or 61e that works as
the fixed yoke and the moving iron core 74e or 64e, and the
magnetic flux density decreases in the attraction portion, enabling
the thrust to be decreased at the end of the stroke of the second
electromagnetic solenoid 7e or the first electromagnetic solenoid
6e. It is therefore allowed to soften the impact on the moving iron
cores 74e, 64e and on the clutch sleeves of the synchronizing
device at the end of the stroke.
[0094] Next, the shift actuator constituted according to a seventh
embodiment of the present invention will be described with
reference to FIGS. 16 and 17. The shift actuator 5f shown in FIGS.
16 and 17 is mechanically substantially the same as the shift
actuator 5b of the third embodiment shown in FIG. 6. Therefore, the
same members are denoted by the same reference numerals and their
description is not repeated.
[0095] The shift actuator 5f according to the seventh embodiment
has a feature in that the feature of the shift actuator 5d of the
fifth embodiment is applied to the shift actuator 5b of the third
embodiment.
[0096] That is, opposing areas of the fixed iron core 62b and the
moving iron core 64b constituting the first electromagnetic
solenoid 6f are so constituted as to decrease, at a position where
the attraction ends shown in FIG. 17(c) after the moving iron core
64b is attracted by the fixed iron core 62b as a result of
supplying a current to the electromagnetic coil 66. In the
illustrated embodiment, the outer peripheral surface 640f of the
moving iron core 64b is opposed to the entire inner peripheral
surface 610 of the casing 61 that works as the fixed yoke when the
shift actuator 5f is in the neutral state shown in FIGS. 16 and
17(a) and when the shift actuator 5f is operated by the second
electromagnetic solenoid 7f that will be described later. In the
illustrated embodiment, further, the opposing area is so
constituted as to become zero (0) between the outer peripheral
surface 640f of the moving iron core 64b and the inner peripheral
surface 610 of the casing 61 working as the fixed yoke, at a
position where attraction ends shown in FIG. 17(c) after the moving
iron core 64b is attracted by the fixed iron core 62b.
[0097] Further, the opposing areas of the fixed iron core 72b and
the moving iron core 74b constituting the second electromagnetic
solenoid 7f are so constituted as to decrease, at a position where
the attraction ends shown in FIG. 17(e) after the moving iron core
74b is attracted by the fixed iron core 72b as a result of
supplying a current to the electromagnetic coil 76. In the
illustrated embodiment, the outer peripheral surface 740f of the
moving iron core 74b is opposed to the entire inner peripheral
surface 710 of the casing 71 that works as the fixed yoke when the
shift actuator 5f is in the neutral state and when the shift
actuator 5f is operated by the first electromagnetic solenoid 6f as
shown in FIGS. 16 and 17(a). In the illustrated embodiment,
further, the opposing area is so constituted as to become zero (0)
between the outer peripheral surface 740f of the moving iron core
74b and the inner peripheral surface 710 of the casing 71 working
as the fixed yoke, at a position where attraction ends shown in
FIG. 17(e) after the moving iron core 74b is attracted by the fixed
iron core 72b.
[0098] The shift actuator 5f according to the seventh embodiment is
constituted as described above. Described below with reference to
FIGS. 17, 19 and 8 are a relationship between the operation
positions of the first electromagnetic solenoid 6f and of the
second electromagnetic solenoid 7f and the corresponding shift
stroke positions of the synchronizing device with which the
transmission (not shown) is furnished, as well as the thrusts at
the operation positions of the first electromagnetic solenoid 6f
and of the second electromagnetic solenoid 7f.
[0099] FIG. 17 illustrates the operation states of the first
electromagnetic solenoid 6f and of the second electromagnetic
solenoid 7f. In FIG. 17, FIG. 17(a) illustrates a state where the
synchronizing device is brought to a neutral position, FIG. 17(b)
illustrates a state where the synchronizing device is brought to a
synchronizing position by the first electromagnetic solenoid 6f,
FIG. 17(c) illustrates a state where the synchronizing device is
brought to a gear-engaging position by the first electromagnetic
solenoid 6f, FIG. 17(d) illustrates a state where the synchronizing
device is brought to a synchronizing position by the second
electromagnetic solenoid 7f, and FIG. 17(e) illustrates a state
where the synchronizing device is brought to a gear-engaging
position by the second electromagnetic solenoid 7f.
[0100] First, described below with reference to FIG. 19(a) is the
thrust at each of the operation positions (graph indicated by a
dot-and-dash line) of when the first electromagnetic solenoid 6f is
energized to be operated from a state where the first
electromagnetic solenoid 6f and the second electromagnetic solenoid
7f are in the gear-engaged state PR2 shown in FIG. 17(e) up to the
gear-engaging position PL2 shown in FIG. 17(c). When an electric
current is supplied to the electromagnetic coil 66 of the first
electromagnetic solenoid 6f in the gear-engaged state shown in FIG.
17(e) (gear-engaged state shown in FIG. 8(e) in the case of the
synchronizing device), the moving iron core 64b is attracted by the
fixed iron core 62b to produce a thrust on the operation rod 63. At
the gear-engaging position PR2 (stroke start position), however,
the thrust is small since the gap is large between the moving iron
core 64b and the fixed iron core 62b. The thrust increases as the
moving iron core 64b moves toward the fixed iron core 62b. As the
neutral position represented by P0 in FIG. 19(a) is passed, i.e.,
as the neutral state shown in FIG. 17(a) is passed (as the neutral
state shown in FIG. 8(a) is passed in the case of the synchronizing
device), the edge 642b of the recess 641b of the moving iron core
64b approaches the edge 622b of the protuberance 621b of the fixed
iron core 62b. At the synchronizing position represented by PL1 in
FIG. 19(a), i.e., in the synchronized state shown in FIG. 17(b) (in
the synchronized state shown in FIG. 8(b) in the case of the
synchronizing device), the two edges most approach each other. In
the synchronized state shown in FIG. 17(b), the thrust increases
since the magnetic flux density increases at the two edges. At this
moment, the right end of the outer peripheral surface 640f of the
moving iron core 64b comes into agreement with, or is positioned
slightly to the right side of, the right end of the inner
peripheral surface 610 of the casing 61 that works as the fixed
yoke, as shown in FIG. 17(b).
[0101] When the synchronizing position represented by PL1 in FIG.
19(a) is passed, there is established a state where the recess 621b
of the moving iron core 64b fits to the protuberance 641b of the
fixed iron core 62b. At this fitting portion, the magnetic flux
acts in the radial direction and hence, the thrust decreases. As
the moving iron core 64b further approaches the fixed iron core
62b, the thrust increases and arrives at the gear-engaged state
(end of the stroke) represented by PL2 in FIG. 19(a), i.e., arrives
at the gear-engaged state shown in FIG. 17(c) (gear-engaged state
shown in FIG. 8(c) in the case of the synchronizing device). Here,
in a range from the synchronizing position represented by PL1 to
the gear-engaging position (end of the stroke) represented by PL2,
the opposing areas of the outer peripheral surface 640f of the
moving iron core 64b and the inner peripheral surface 610 of the
casing 61 working as a fixed yoke are so constituted as to
gradually decrease. Therefore, reluctance increases between the
moving iron core 64b and the casing 61 working as the fixed yoke,
and the magnetic flux density decreases in the attraction portion,
making it possible to decrease the thrust at the end of the stroke
of the first electromagnetic solenoid 6b. It is therefore allowed
to soften the impact on the moving iron core 64b and on the clutch
sleeves of the synchronizing device at the end of the stroke.
[0102] Next, described below with reference to FIG. 19(b) is the
thrust at each of the operation positions (graph indicated by a
dot-and-dash line) of when the second electromagnetic solenoid 7b
is energized to be operated from a state where the first
electromagnetic solenoid 6f and the second electromagnetic solenoid
7f are in the gear-engaged state PL2 shown in FIG. 17(c) up to the
gear-engaging position PR2 shown in FIG. 17(e). When an electric
current is supplied to the electromagnetic coil 76 of the second
electromagnetic solenoid 7f in the gear-engaged state shown in FIG.
17(c) (gear-engaged state shown in FIG. 8(c) in the case of the
synchronizing device), the moving iron core 74b is attracted by the
fixed iron core 72b to produce a thrust on the operation rod 73. At
the gear-engaging position PL2 (stroke start position), however,
the thrust is small since the gap is large between the moving iron
core 74b and the fixed iron core 72b. The thrust increases as the
moving iron core 74b moves toward the fixed iron core 72b. As the
neutral position represented by P0 in FIG. 19(b) is passed, i.e.,
as the neutral state shown in FIG. 17(a) is passed (as the neutral
state shown in FIG. 8(a) is passed in the case of the synchronizing
device), the edge 742b of the recess 741b of the moving iron core
74b approaches the edge 722b of the protuberance 721b of the fixed
iron core 72b. At the synchronizing position represented by PR1 in
FIG. 19(b), i.e., in the synchronized state shown in FIG. 17(d) (in
the synchronized state shown in FIG. 8(d) in the case of the
synchronizing device), the two edges most approach each other. In
the synchronized state shown in FIG. 17(d), the thrust increases
since the magnetic flux density increases at the two edges. At this
moment, the left end of the outer peripheral surface 740f of the
moving iron core 74b comes into agreement with, or is positioned
slightly to the right side of, the left end of the inner peripheral
surface 710 of the casing 71 that works as the fixed yoke, as shown
in FIG. 17(d).
[0103] When the synchronizing position represented by PR1 in FIG.
19(b) is passed, there is established a state where the recess 721b
of the moving iron core 74b fits to the protuberance 741b of the
fixed iron core 72b. At this fitting portion, the magnetic flux
acts in the radial direction and hence, the thrust decreases. As
the moving iron core 74b further approaches the fixed iron core
72b, the thrust increases and arrives at the gear-engaged state
(end of the stroke) represented by PR2 in FIG. 19(b), i.e., arrives
at the gear-engaged state shown in FIG. 17(e) (gear-engaged state
shown in FIG. 8(e) in the case of the synchronizing device). Here,
in a range of from the synchronizing position represented by PR1 to
the gear-engaging position (end of the stroke) represented by PR2,
the opposing areas of the outer peripheral surface 740f of the
moving iron core 74b and the inner peripheral surface 710 of the
casing 71 working as a fixed yoke are so constituted as to
gradually decrease. Therefore, reluctance increases between the
moving iron core 74b and the casing 71 working as the fixed yoke,
and the magnetic flux density decreases in the attraction portion,
making it possible to decrease the thrust at the end of the stroke
of the second electromagnetic solenoid 7b. It is therefore allowed
to soften the impact on the moving iron core 74b and on the clutch
sleeves of the synchronizing device at the end of the stroke.
[0104] As described above, the shift actuator 5f comprising the
first electromagnetic solenoid 6f and the second electromagnetic
solenoid 7f according to the seventh embodiment has such
characteristics that the thrust once swells at the synchronizing
positions (PL1, PR1) of the synchronizing device. Namely, a
predetermined thrust is obtained at the synchronizing position
where the operation force is required, making it possible to use
the electromagnetic solenoids of a small size. In the shift
actuator 5f according to the seventh embodiment, further, an
increase in the thrust is suppressed at the end of the stroke, and
the impact on the moving iron core and on the clutch sleeves of the
synchronizing device at the end of the stroke is softened. The
seventh embodiment shown in FIGS. 16 and 17 has dealt with a case
where the invention was applied to the push-type actuator of the
sixth embodiment. However, the same effect is obtained even when
the present invention is applied to the pull-type actuator of the
sixth embodiment.
[0105] Next, the shift actuator constituted according to an eighth
embodiment of the present invention will be described with
reference to FIG. 18. The shift actuator 5g shown in FIG. 18 is
mechanically substantially the same as the shift actuator 5c of the
fourth embodiment shown in FIG. 9. Therefore, the same members are
denoted by the same reference numerals and their description is not
repeated.
[0106] The shift actuator 5g according to the eighth embodiment has
a feature in that the feature of the shift actuator 5d of the fifth
embodiment and the feature of the shift actuator 5f of the seventh
embodiment are applied to the shift actuator 5c of the fourth
embodiment.
[0107] That is, in the shift actuator 5g of the eighth embodiment,
the outer peripheral surfaces of the stepped protuberances 621c,
721c formed at the centers on the end surfaces of the fixed iron
cores 62c, 72c constituting the first electromagnetic solenoid 6g
and the second electromagnetic solenoid 7g, as well as the inner
surfaces of the stepped recesses 641c, 741c of the moving iron
cores 64c, 74c corresponding to the above protuberance 621c and
721c formed at the centers on the end surfaces of the fixed iron
cores 62c and 72c are tapered. Further, the fixed iron cores 62c,
72c and the moving iron cores 64c, 74c constituting the first
electromagnetic solenoid 6g and the second electromagnetic solenoid
7g are so constituted that the areas opposing to each other of the
outer peripheral surfaces 640g, 740g of the moving iron cores 64c,
74c and the inner peripheral surfaces 610, 710 of the casings 61,
71 working as fixed yokes decrease, at each a position where the
attraction ends. The thus constituted shift actuator 5g exhibits
intermediate thrust characteristics as indicated by two-dot chain
lines in FIGS. 19(a) and 19(b) lying between the thrust
characteristics of the shift actuator 5f of the seventh embodiment
indicated by a dot-and-dash chain line and the thrust
characteristics of the actuator 5d of the fifth embodiment
indicated by a solid line. The thrust characteristics approach
those indicated by the solid lines when the outer peripheral
surfaces of the protuberances 621c, 721c and the outer peripheral
surfaces of the recesses 641c, 741c have a small tapered angle, and
approach those indicated by the broken lines when the outer
peripheral surfaces of the protuberances 621c, 721c and the outer
peripheral surfaces of the recesses 641c, 741c have a large tapered
angle.
[0108] Next, a ninth embodiment of the shift actuator constituted
according to the present invention will be described with reference
to FIGS. 20 and 21. In the shift actuator 5h of the ninth
embodiment shown in FIGS. 20 and 21, the same members as those of
the above-mentioned embodiments are denoted by the same reference
numerals but are not described again in detail.
[0109] The actuator 5h according to the ninth embodiment has a
first electromagnetic solenoid 6h and a second electromagnetic
solenoid 7h for actuating the operation lever 50 mounted on the
control shaft 32 in the directions opposite to each other.
[0110] The first electromagnetic solenoid 6h comprises an
electromagnetic coil 61h, a fixed iron core 62h excited by the
electromagnetic coil 61h, a first moving iron core 63h disposed to
be allowed to approach, and separate away from, the fixed iron core
62h, a second moving iron core 64h fitted slidably onto the outer
peripheral surface of the first moving iron core 63h, and an
operation rod 65h mounted on the first moving iron core 63h.
[0111] The electromagnetic coil 61h is wound on a bobbin 66h made
of a nonmagnetic material such as synthetic resin. The fixed iron
core 62h is made of a magnetic material and comprises a base
portion 621h, a first cylindrical attraction portion 622h that
protrudes from the central portion of the base portion 621h and is
positioned in the electromagnetic coil 61h, a cylindrical portion
623h protruding in the same direction as the first attraction
portion 622h from the outer periphery of the base portion 621h, a
second annular attraction portion 624h provided at an end of the
cylindrical portion 623h, and a coil accommodation portion 624h
formed between the first attraction portion 622h and the
cylindrical portion 623h. An electromagnetic coil 61h wound on the
bobbin 66h is disposed in the coil accommodation portion 625h. The
first moving iron core 63h is made of a magnetic material in a
cylindrical shape and is movably disposed in the electromagnetic
coil 61h. The first moving iron core 63h has a mounting hole 631h
which is formed in the central portion thereof and of which an
inner diameter corresponds to the outer diameter of a
small-diameter mounting portion 651h formed at the right portion of
the operation rod 65h in the drawing. The first moving iron core
63h is mounted by fitting its mounting hole 631h into the mounting
portion 651h of the operation rod 65h. The second moving iron core
64h is made of a magnetic material in an annular shape, and has a
mounting hole 641h of an inner diameter corresponding to the outer
diameter of the first moving iron core 63h. By slidably fitting the
mounting hole 641h onto the outer peripheral surface of the first
moving iron core 63h, the thus formed second moving iron core 64h
is so disposed that the outer peripheral portion thereof is opposed
to the second attraction portion 624h of the fixed iron core 62h. A
snap ring 67h is mounted on the outer peripheral surface of the
first moving iron core 63h at the central portion thereof in the
axial direction. The snap ring 67h limits the second moving iron
core 64h from moving toward the fixed iron core 62h. Therefore, the
snap ring 67h serves as a limiting means for limiting the second
moving iron core 64h from moving toward the fixed iron core 62h
side.
[0112] The operation rod 65h mounting the first moving iron core
63h is made of a nonmagnetic material such as stainless steel, and
is disposed being inserted in a through hole 626h formed in the
central portion of the base portion 621h and the first attraction
portion 622h of the fixed iron core 62h.
[0113] A cover member 69h is disposed at the right end of the fixed
iron core 62h in FIG. 20, and is mounted on a cylindrical portion
623h by screws 690h. The cover member 69h covers the first moving
iron core 63h and the second moving iron core 64h.
[0114] When a current is supplied to the electromagnetic coil 61h
of the thus constituted first electromagnetic solenoid 6h, the
first moving iron core 63h and the second moving iron core 64h are
attracted by the first attraction portion 622h and by the second
attraction portion 624h of the fixed iron core 62h. As a result,
the operation rod 65h onto which the first moving iron core 63h and
the second moving iron core 64h are mounted moves toward the left
in FIG. 20, and its end acts on the operation lever 50 to turn
clockwise on the control shaft 32 as a center. Therefore, the shift
lever 34 constituted integratedly with the shift sleeve 35 mounted
on the control shaft 32 is shifted in one direction. Here, a
position where the second moving iron core 64h comes in contact
with the second attraction portion 624h of the fixed iron core 62h
in the range of stroke of the operation rod 65h, is so constituted
as to correspond to a position just after the synchronizing
position of the synchronizing device as will be described
later.
[0115] The second electromagnetic solenoid 7h will be described
next.
[0116] The second electromagnetic solenoid 7h is disposed to be
opposed to the first electromagnetic solenoid 6h. Like the first
electromagnetic solenoid 6h, the second electromagnetic solenoid
7h, too, comprises an electromagnetic coil 71h, a fixed iron core
72h excited by the electromagnetic coil 71h, a first moving iron
core 73h disposed to be allowed to approach, and separate away
from, the fixed iron core 72h, a second moving iron core 74h fitted
slidably onto the outer peripheral surface of the first moving iron
core 73h, and an operation rod 75h mounted on the first moving iron
core 73h. Further, like the first electromagnetic solenoid 6h, the
second electromagnetic solenoid 7h, too, comprises a bobbin 76h on
which the electromagnetic coil 71h is wound, a snap ring 77h that
is fitted onto the outer peripheral surface of the first moving
iron core 73h and works as limiting means for limiting the second
moving iron core 74h from moving toward the fixed iron core 72h
side, and a cover member 79h for covering the first moving iron
core 73h and the second moving iron core 74h.
[0117] When a current is supplied to the electromagnetic coil 71h
of the thus constituted second electromagnetic solenoid 7h, the
first moving iron core 73h and the second moving iron core 74h are
attracted by the first attraction portion 722h and by the second
attraction portion 724h of the fixed iron core 72h. As a result,
the operation rod 75h to which the first moving iron core 73h and
the second moving iron core 74h are mounted moves toward the right
in FIG. 20, and its end acts on the operation lever 50 to turn
counterclockwise on the control shaft 32 as a center. Therefore,
the shift lever 34 constituted integratedly with the shift sleeve
35 mounted on the control shaft 32 is shifted in one direction.
Here, a position where the second moving iron core 74h comes in
contact with the second attraction portion 724h of the fixed iron
core 72h in the range of stroke of the operation rod 75h, is so
constituted as to correspond to a position just after the
synchronizing position of the synchronizing device as will be
described later.
[0118] The shift actuator 5h according to the ninth embodiment is
constituted as described above. Described below with reference to
FIGS. 21, 22 and 8 are a relationship between the operation
positions of the first electromagnetic solenoid 6h and of the
second electromagnetic solenoid 7h and the corresponding shift
stroke positions of the synchronizing device with which the
transmission (not shown) is furnished, as well as the thrusts at
the operation positions of the first electromagnetic solenoid 6h
and of the second electromagnetic solenoid 7h.
[0119] FIG. 21 illustrates the operation states of the first
electromagnetic solenoid 6h and of the second electromagnetic
solenoid 7h. In FIG. 21, FIG. 21(a) illustrates a state where the
synchronizing device is brought to a neutral position, FIG. 21(b)
illustrates a state where the synchronizing device is brought up to
a position just after a synchronizing position by the first
electromagnetic solenoid 6h, FIG. 21(c) illustrates a state where
the synchronizing device is brought to a gear-engaging position by
the first electromagnetic solenoid 6h, FIG. 21(d) illustrates a
state where the synchronizing device is brought up to a position
just after a synchronizing position by the second electromagnetic
solenoid 7h, and FIG. 21(e) illustrates a state where the
synchronizing device is brought to a gear-engaging position by the
second electromagnetic solenoid 7h.
[0120] FIG. 22 is a diagram illustrating a relationship between the
thrusts and the operation positions of operation rods 65h and 75h
of the first electromagnetic solenoid 6h and of the second
electromagnetic solenoid 7h. In FIGS. 22(a) and 22(b), the
operation position P0 of the electromagnetic solenoid represents a
state where the first electromagnetic solenoid 6h and the second
electromagnetic solenoid 7h are in the neutral state shown in FIG.
21(a), PR2 represents a state where the first electromagnetic
solenoid 6h and the second electromagnetic solenoid 7h are at the
gear-engaging position shown in FIG. 21(e), PL2 represents a state
where the first electromagnetic solenoid 6h and the second
electromagnetic solenoid 7h are at the gear-engaging position shown
in FIG. 21(c), PLM represents a state where the first
electromagnetic solenoid 6h and the second electromagnetic solenoid
7h are at positions just after the synchronizing positions
corresponding to the state shown in FIG. 21(b), and PRM represents
a state where the first electromagnetic solenoid 6h and the second
electromagnetic solenoid 7h are at positions just after the
synchronizing positions corresponding to the state shown in FIG.
21(d). FIG. 22(a) is a graph illustrating the thrust at each of the
operation positions of when the first electromagnetic solenoid 6h
is energized to be operated from a state where the first
electromagnetic solenoid 6h and the second electromagnetic solenoid
7h are in the gear-engaged state PR2 shown in FIG. 21(e) up to the
gear-engaging position PL2 shown in FIG. 21(c). FIG. 22(b) is a
graph illustrating the thrust at each of the operation positions of
when the second electromagnetic solenoid 7h is energized to be
operated from a state where the first electromagnetic solenoid 6h
and the second electromagnetic solenoid 7h are in the gear-engaged
state PL2 shown in FIG. 21(c) up to the gear-engaging position PR2
shown in FIG. 21(e).
[0121] First, described below with reference to FIG. 22(a) is the
thrust at each of the operation positions (graph indicated by the
solid line) of when the first electromagnetic solenoid 6h is
energized to be operated from a state where the first
electromagnetic solenoid 6h and the second electromagnetic solenoid
7h are in the gear-engaged state PR2 shown in FIG. 21(e) up to the
gear-engaging position PL2 shown in FIG. 21(c).
[0122] When an electric current is supplied to the electromagnetic
coil 61h of the first electromagnetic solenoid 6h in the
gear-engaged state shown in FIG. 21(e) (gear-engaged state shown in
FIG. 8(e) in the case of the synchronizing device), the fixed iron
core 62h is excited, and the first moving iron core 63h and the
second moving iron core 64h are attracted by the first attraction
portion 622h and by the second attraction portion 624h to produce a
thrust on the operation rod 65h. At the gear-engaging position PR2
(stroke start position), however, the thrust is small as indicated
by a solid line (1) since the gap is large between the first moving
iron core 63h, the second moving iron core 64h and the first
attraction portion 622h, the second attraction portion 624h. The
thrust increases as indicated by the solid line (1) as the first
moving iron core 63h and the second moving iron core 64h move
toward the first attraction portion 622h and the second attraction
portion 624h. As the neutral position represented by P0 in FIG.
22(a) is passed, i.e., as the neutral state shown in FIG. 21(a) is
passed (as the neutral state shown in FIG. 8(a) is passed in the
case of the synchronizing device), the gap decreases between the
second moving iron core 64h and the second attraction portion 624h,
and the thrust sharply increases. At the synchronizing position
represented by PL1 in FIG. 22(a), i.e., at a position just before
the second moving iron core 64h comes in contact with the second
attraction portion 624h (at the synchronizing position shown in
FIG. 8(b) in the case of the synchronizing device), therefore, a
large thrust is obtained as indicated by the solid line (1)
enabling the synchronizing device to quickly execute the
synchronizing action.
[0123] As the operation rod 65h arrives at a position just after
the synchronizing position represented by PLM in FIG. 22(a), the
second moving core 64h comes in contact with the second attraction
portion 624h, and the thrust increases up to a position PLM just
after the synchronizing position, as indicated by the solid line
(1). As the second moving iron core 64h comes in contact with the
second attraction portion 624h, the second moving iron core 64h is
limited from moving toward the left in the drawing. After the
motion of the second moving iron core 64h is limited, the first
moving iron core 63h is attracted by the first attraction portion
622h to produce a thrust. Therefore, the thrust characteristics
become as indicated by a solid line (2) of from the position PLM
just after the synchronizing position in FIG. 22(a) up to the
gear-engaging position (end of stroke) represented by PL2, i.e., up
to the gear-engaging position shown in FIG. 21(c) (gear-engaging
position shown in FIG. 8(c) in the case of the synchronizing
device). That is, the thrust drops at a moment when the position
PLM just after the synchronizing position is passed. Thereafter,
the thrust increases in compliance with a curve of secondary degree
toward the gear-engaging position (end of stroke) represented by
PL2 in FIG. 22(a). The gear-engaged state shown in FIG. 21(c)
(gear-engaged state shown in FIG. 8(c) in the case of the
synchronizing device) is assumed at the gear-engaging position (end
of stroke) represented by PL2.
[0124] Next, described below with reference to FIG. 22(b) is the
thrust at each of the operation positions (graph indicated by a
solid line) of when the second electromagnetic solenoid 7h is
energized to be operated from a state where the first
electromagnetic solenoid 6h and the second electromagnetic solenoid
7h are in the gear-engaged state PL2 shown in FIG. 21(c) up to the
gear-engaging position PR2 shown in FIG. 21(e).
[0125] When an electric current is supplied to the electromagnetic
coil 71h of the second electromagnetic solenoid 7h in the
gear-engaged state shown in FIG. 21(c) (gear-engaged state shown in
FIG. 8(c) in the case of the synchronizing device), the fixed iron
core 72h is excited, and the first moving iron core 73h and the
second moving iron core 74h are attracted by the first attraction
portion 722h and by the second attraction portion 724h to produce a
thrust on the operation rod 75h. At the gear-engaging position PL2
(stroke start position), however, the thrust is small as indicated
by the solid line (1) since the gap is large between the first
moving iron core 73h, the second moving iron core 74h and the first
attraction portion 722h, the second attraction portion 724h. The
thrust increases as indicated by the solid line (1) as the first
moving iron core 73h and the second moving iron core 74h move
toward the first attraction portion 722h and the second attraction
portion 724h. As the neutral position represented by P0 in FIG.
22(b) is passed, i.e., as the neutral state shown in FIG. 21(a) is
passed (as the neutral state shown in FIG. 8(a) is passed in the
case of the synchronizing device), the gap decreases between the
second moving iron core 74h and the second attraction portion 724h,
and the thrust sharply increases. At the synchronizing position
represented by PR1 in FIG. 22(b), i.e., at a position just before
the second moving iron core 74h comes in contact with the second
attraction portion 724h (at the synchronizing position shown in
FIG. 8(d) in the case of the synchronizing device), therefore, a
large thrust is obtained as indicated by the solid line (1)
enabling the synchronizing device to quickly execute the
synchronizing action.
[0126] As the operation rod 75h arrives at a position just after
the synchronizing position represented by PRM in FIG. 22(b), the
second moving core 74h comes in contact with the second attraction
portion 724h, and the thrust increases up to the position PRM just
after the synchronizing position, as indicated by the solid line
(1). As the second moving iron core 74h comes in contact with the
second attraction portion 724h, the second moving iron core 74h is
limited from moving toward the right in the drawing. After the
motion of the second moving iron core 74h is limited, the first
moving iron core 73h is attracted by the first attraction portion
722h to produce a thrust. Therefore, the thrust characteristics
become as indicated by a solid line (2) of from the position PRM
just after the synchronizing position in FIG. 22(b) up to the
gear-engaging position (end of stroke) represented by PR2, i.e., up
to the gear-engaging position shown in FIG. 21(e) (gear-engaging
position shown in FIG. 8(e) in the case of the synchronizing
device). That is, the thrust decreases at a moment when the
position PRM just after the synchronizing position is passed.
Thereafter, the thrust increases in compliance with a curve of
secondary degree toward the gear-engaging position (end of stroke)
represented by PR2 in FIG. 22(b). The gear-engaged state shown in
FIG. 21(e) (gear-engaged state shown in FIG. 8(e) in the case of
the synchronizing device) is assumed at the gear-engaging position
(end of stroke) represented by PR2.
[0127] As described above, the shift actuator 5h comprising the
first electromagnetic solenoid 6h and the second electromagnetic
solenoid 7h according to the ninth embodiment exhibits thrust
characteristics that once rise near the synchronizing position of
the synchronizing device. Accordingly, a required thrust can be
obtained at the synchronizing position where the operation force is
required and hence, it becomes possible to make the electromagnetic
solenoids into a small size. That is, in FIGS. 22(a) and 22(b),
broken lines indicate thrust characteristics of when the shift
actuator employing the conventional electromagnetic solenoids is
constituted in the same size as the shift actuator 5h of the ninth
embodiment, from which it will be learned that the thrust of the
shift actuator employing the conventional electromagnetic solenoids
is small at the synchronizing positions (PL1, PR1) as compared to
the thrust characteristics of the shift actuator 5h of the ninth
embodiment indicated by solid lines. Therefore, the conventional
shift actuator must employ the electromagnetic solenoids having an
increased ability in order to produce the thrust comparable to that
of the shift actuator 5h of the ninth embodiment at the
synchronizing positions (PL1, PR1).
[0128] In the foregoing were described the embodiments in which the
present invention is applied to the shift actuator that constitutes
the gear change device in combination with the select actuator. The
shift actuator of the present invention can be also applied to, for
example, a shift-assisting device for assisting the force of
operation in the shifting direction in the manual
transmissions.
* * * * *