U.S. patent application number 09/898057 was filed with the patent office on 2002-10-31 for synchronous mesh-type automatic transmission control device.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Fukuda, Takehisa.
Application Number | 20020157491 09/898057 |
Document ID | / |
Family ID | 26601823 |
Filed Date | 2002-10-31 |
United States Patent
Application |
20020157491 |
Kind Code |
A1 |
Fukuda, Takehisa |
October 31, 2002 |
SYNCHRONOUS MESH-TYPE AUTOMATIC TRANSMISSION CONTROL DEVICE
Abstract
The present invention provides a synchronous mesh-type automatic
transmission control device for an automotive vehicle capable of
stably shortening a transmission time, and simultaneously having a
high durability. The control system comprises an input shaft 13
coupled with a crank shaft 1a of an internal combustion engine 1
trough a clutch mechanism 2, an output shaft 16 coupled with the
input shaft 13 through any one set of gears selected from the
plural sets of transmission gears 17 to 21 each having a different
gear ratio, a coupling mechanism 22 for coupling the input shaft 13
with the output shaft 16 by selecting one set of gears as
above-mentioned, a shift and select actuator 5 for controlling a
shift position and a select position of the coupling mechanism 22,
and a control means 4, whereby a manipulating value of the shift
and select actuator 5 is controlled by inputting its position
signal, and moreover, a shift speed of the shift and select
actuator 5 is controlled according to a rotating speed difference
signal of the put shaft 13 and the output shaft 16 of the internal
combustion engine 1.
Inventors: |
Fukuda, Takehisa; (Tokyo,
JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
Suite 800
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037-3213
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
|
Family ID: |
26601823 |
Appl. No.: |
09/898057 |
Filed: |
July 5, 2001 |
Current U.S.
Class: |
74/335 |
Current CPC
Class: |
F16H 2061/2823 20130101;
F16H 61/28 20130101; F16H 63/502 20130101; F16H 61/2807 20130101;
F16H 2059/6807 20130101; F16H 59/46 20130101; Y10T 74/19251
20150115; Y10T 74/1926 20150115 |
Class at
Publication: |
74/335 |
International
Class: |
F16H 061/00; F16H
059/00; F16H 063/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2000 |
JP |
2000-309824 |
Feb 2, 2001 |
JP |
2001-027214 |
Claims
What is claimed is:
1. A synchronous mesh-type automatic transmission control device
comprising: an input shaft coupled with a crank shaft of an
internal combustion engine through a clutch, a coupling mechanism
including plural transmission sets, wherein each transmission set
has a pair of transmission units with a different transmission
ratio to each other, a select and shift actuator for selecting one
of said plural transmission sets based on a select position and for
selecting one of said pair of transmission units in the selected
one of said plural transmission sets based on a shift position, an
output shaft coupled with said input shaft through the selected one
of said pair of transmission units in the selected one of said
plural transmission sets, a select and shift position sensor for
outputting a select position signal according to said select
position of said select and shift actuator and a shift position
signal according to said shift position of said select and shift
actuator, and a control means for generating a driving signal
varied on a rotating speed difference of said input shaft and said
output shaft and for driving said select and shift actuator by an
operating speed based on said driving signal.
2. The synchronous mesh-type automatic transmission control device
claimed in claim 1, wherein said control means controls said
operating speed so that the operating speed at the large value of
the rotating speed difference is larger than the operating speed at
the small value of the rotating speed difference.
3. The synchronous mesh-type automatic transmission control device
claimed in claim 1, wherein said each transmission set has a sleeve
gear for selecting one of said pair of transmission units and said
control means controls the operating speed of said sleeve gear
according to the rotating speed difference of said input shaft and
said output shaft when said sleeve gear is moved from a neutral
position to the position according to said one of said pair of
transmission units.
4. The synchronous mesh-type automatic transmission control device
claimed in claim 3, wherein said control means controls the
operating speed of said sleeve gear so that the operating speed at
the large value of the rotating speed difference is larger than
operating speed at the small value of the rotating speed
difference.
Description
1. TECHNICAL FIELD
[0001] The present invention relates to an automatic transmission
control device, and more particularly to a synchronous mesh-type
automatic transmission control device for an automotive vehicle
wherein, a stabilization of an operating time at changing a speed
and a durability of a synchronizing mechanism are capable of being
realized.
2. BACKGROUND ART
[0002] A synchronous mesh-type automatic transmission control
device for a vehicle, for example, is disclosed in Japanese
laid-open Patent No. 63-270252. In this prior art, an internal
combustion engine and a synchronous mesh-type automatic
transmission are coupled through an electromagnetic clutch. In
changing a transmission gear, a throttle opening is controlled to
maintain a difference of a rotating speed of the internal
combustion engine between when a electromagnetic clutch is released
and coupled within a predetermined permissible range. At the same
time, a relation between the rotating speed of the internal
combustion engine and the throttle opening is compensated by a
learning routine program at each speed changing operation to cope
with any variations of the engine characteristics and an operating
condition, thus making it possible to reduce a shock when the gear
is changed.
[0003] The synchronous mesh-type automatic transmission as shown in
the above prior art, a pair of three position oil pressure
cylinders for manipulating a shift and select lever along an axial
and rotating direction are used for selecting a shift rod by
driving a select three position oil pressure cylinder, for moving
the selected shift rod by driving a shift three position oil
pressure cylinder, and then for switching a transmission stage. In
addition to the synchronous mesh-type automatic transmission driven
by an oil pressure as explained above, an electric synchronous
mesh-type automatic transmission with two motors for a shift and
select driving operation is generally used.
[0004] In the electric synchronous mesh-type automatic
transmission, a gear change operation for coupling the aimed gears
is controlled in the following manner. A coupling means to be
operated is selected by a select actuator while a select position
is being controlled by a position signal of a select position
sensor, and the coupling means is transferred for coupling the
aimed gears by a shift actuator while a shift position is being
controlled by a position signal of a shift position sensor. Namely,
a control of the shift actuator is executed in a way, wherein the
shift and select position is controlled to coincide with an aimed
shift and select position by controlling a driving variable based
on a deviation signal as a parameter between the aimed shift and
select position and an actual shift and select position detected by
the shift and select position sensor. In controlling the shift
actuator and the select actuator, it is a usual way to employ a PID
control method with a position feedback, wherein P, I and D are
respectively a proportional, an integral and a derivative
element.
[0005] In the synchronous mesh-type automatic transmission
according to the prior art, wherein a transmission gear stage is
changed by controlling a shift and select position, the shift and
select position are controlled to the aimed preset shift and select
position. But in this prior device, as a control speed by the shift
and select position was fixed, a driving feeling was not so good,
and there was also a feeling of something wrong as well as a
prolonged shifting time caused by a variation in an using
environment, a driving condition, constitutional parts and the
manipulated variable required for a shift operation due to a time
lapse. Moreover, if the shift operation is fastened for reducing a
time of changing the speed to cope with the above mentioned
shortcomings, another problem arises, wherein a synchronizing
mechanism for obtaining a synchronous rotation deteriorates in
performance.
SUMMARY OF THE INVENTION
[0006] In view of the above, it is the object of the present
invention to provide a synchronous mesh-type automatic transmission
control device for an automotive vehicle capable of stably
shortening a time for a speed changing operation and, at the same
time, having a high durability.
[0007] According to this invention a synchronous mesh-type
automatic transmission control device comprising:
[0008] an input shaft coupled with a crank shaft of an internal
combustion engine through a clutch,
[0009] a coupling mechanism including plural transmission sets,
wherein each transmission set has a pair of transmission units with
a different transmission ratio to each other,
[0010] a select and shift actuator for selecting one of said plural
transmission sets based on a select position and for selecting one
of said pair of transmission units in the selected one of said
plural transmission sets based on a shift position,
[0011] an output shaft coupled with said input shaft through the
selected one of said pair of transmission units in the selected one
of said plural transmission sets,
[0012] a select and shift position sensor for outputting a select
position signal according to said select position of said select
and shift actuator and a shift position signal according to said
shift position of said select and shift actuator, and
[0013] a control means for generating a driving signal varied on a
rotating speed difference of said input shaft and said output shaft
and for driving said select and shift actuator by an operating
speed based on said driving signal.
[0014] According to the synchronous mesh-type automatic
transmission control device in this invention, as the operating
speed for the select and shift actuator is configured to be varied
based on the rotating speed difference between the input and the
output shaft, the time required for the speed change operation is
capable of being stably shortened independent of the variations in
using environment, operating conditions or constitutional parts,
and the control device having the synchronizing mechanism with high
reliability and durability is capable of being provided.
[0015] Furthermore, the synchronous mesh-type automatic
transmission control device, wherein said control means controls
said operating speed so that the operating speed at the large value
of the rotating speed difference is larger than the operating speed
at the small value of the rotating speed difference.
[0016] According to the synchronous mesh-type automatic
transmission control device in tis invention, as the larger is the
rotating speed difference of the input and the output shaft, the
larger the shift operating speed by the select and shift actuator
is controlled. Similarly, the smaller is the rotating speed
difference of the input and the output shaft, the smaller the shift
operating speed by the select and shift actuator is controlled.
Thereby durability of the synchronizing mechanism is capable of
being effectively raised.
[0017] Moreover, the synchronous mesh-type automatic transmission
control device, wherein said each transmission set has a sleeve
gear for selecting one of said pair of transmission units and said
control means controls the operating speed of said sleeve gear
according to the rotating speed difference of said input shaft and
said output shaft when said sleeve gear is moved from a neutral
position to the position according to said one of said pair of
transmission units.
[0018] In the synchronous mesh-type automatic transmission control
device according to the present invention, wherein said each
transmission set has the sleeve gear for selecting one of said pair
of transmission units and said control means controls the operating
speed of the sleeve gear according to the rotating speed difference
of the input and the output shaft. Therefore, durability of the
synchronizing mechanism is capable of being promoted.
[0019] In addition, the synchronous mesh-type automatic
transmission control device, wherein said control means controls
the operating speed of said sleeve gear so that the operating speed
at the large value of the rotating speed difference is larger than
operating speed at the small value of in the rotating speed
difference.
[0020] Furthermore, as the operating speed of the sleeve gear is
controlled to be high or low by the control means respectively
depending on whether the rotating speed difference of the input and
the output shaft is large or small, durability of the synchronizing
mechanism is capable of being effectively promoted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a configuration of a synchronous mesh-type
automatic transmission control device in an embodiment 1 according
to the present invention.
[0022] FIG. 2 is a configuration for explaining a speed change
mechanism of the synchronous mesh-type automatic transmission
control device in the embodiment 1 according to the present
invention.
[0023] FIG. 3 is a configuration for explaining a synchronous
mechanism of the synchronous mesh-type automatic transmission
control device in the embodiment 1 according to the present
invention.
[0024] FIG. 4 is a graph for explaining a shift operation of the
synchronous mesh-type automatic transmission control device in the
embodiment 1 according to the present invention.
[0025] FIG. 5 is a graph for explaining a select operation of the
synchronous mesh-type automatic transmission control device in the
embodiment 1 according to the present invention.
[0026] FIG. 6 is a characteristic curve for explaining a renewed
value of a shift position of the synchronous mesh-type automatic
transmission control device in the embodiment 1 according to the
present invention.
[0027] FIG. 7 is a functional flowchart for explaining an operation
of the synchronous mesh-type automatic transmission control device
in the embodiment 1 according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] FIG. 1 to FIG. 7 are for explaining a configuration and an
operation of a synchronous mesh-type automatic transmission control
device in an embodiment 1 according to the present invention.
Namely, FIG. 1 is for explaining a configuration of a synchronous
mesh-type automatic transmission control device, FIG. 2 is for
explaining a speed change mechanism, FIG. 3 is for explaining a
configuration of a synchronous mechanism, FIG. 4 and FIG. 5 are for
explaining a shift and a select operation, FIG. 6 is a
characteristic curve of a renewed aimed shift position and FIG. 7
is a flowchart for explaining a control operation. In FIG. 1, an
internal combustion engine 1 is laden in an automotive vehicle, an
electro-magnetic clutch 2 set up with a crank shaft 1a of the
internal combustion engine 1 is for coupling the internal
combustion engine 1 with the synchronous mesh-type automatic
transmission 3, a control unit 4 as a control means is for
controlling the synchronous mesh-type automatic transmission 3, a
select and shift actuator 5 controlled by the control unit 4 as a
control means is for manipulating a gear coupling of the
synchronous mesh-type automatic transmission 3 to be described in
detail later on, and a select and shift position sensor 6 is for
detecting a manipulated position of the select and shift actuator
5.
[0029] Furthermore, a throttle position sensor 7 located on an
intake 8 of the internal combustion engine 1 is for detecting an
opening of a throttle valve 9, an accelerator position sensor 10 is
for detecting a position of a stepped-down accelerator not shown in
the drawings, a throttle actuator 11 is for manipulating the
opening of the throttle valve 9 according to an output from the
accelerator position sensor 10 or based on a stored program of the
control unit 4 when a speed shift operation takes place, and a
shift lever 12 is for commanding a shift operating position by a
driver to the control unit 4.
[0030] The synchronous mesh-type automatic transmission 3 comprises
an input shaft 13 coupled with the electromagnetic clutch 2, a
counter shaft 15 coupled with the input shaft 13 through a primary
gear set 14, an output shaft 16 for driving an automotive vehicle.
The synchronous mesh-type automatic transmission 3 also comprises
three transmission sets TS1, TS2, TS3. The transmission set TSI
includes a pair of transmission unit TU1, and TU2. The transmission
unit TU1 has the primary gear set 14, and the transmission unit TS2
has a 3.sup.rd speed gears set 19. The transmission set TS2
includes a pair of transmission unit TU3 and TU4. The transmission
unit TU3 has a 2.sup.nd speed gear set 18, and the transmission
unit TU4 has a 1.sup.st speed gear set 17. The transmission set TU3
includes a pair of transmission unit TU5 and TU6. The transmission
unit TU5 has a reverse gear set 21 and the transmission unit TU6
has a 5.sup.th speed gear set 20. The 1.sup.st speed gear set 17,
the 2.sup.nd speed gear set 18, the 3.sup.rd speed gear set 19, the
5.sup.th speed gear set 20 and the reverse gear set 21 installed
respectively as a pair of gears between the counter shaft 15 and
the output shaft 16. Each of the transmission set TS1, TS2 and TS3
has a sleeve gear 22a, 22b and 22c as a coupling mechanism which is
fixed to the output shaft 16 in a rotating direction and are
simultaneously installed to be movable to an axial direction of the
output shaft 16. The sleeve gear 22a is selectively coupled with
the gear set 14 or 19, by its movement on axis direction of the
output shaft 16. As a same, the sleeve gear 22b and 22c are
selectively coupled with the gear set 18 or 17 and with the gear
set 21 or 20. The synchronous mesh-type automatic transmission 3 is
also configured, wherein one gear on a side of the counter shaft 15
of each gear set of 17, 18, 19, 20 and 21 is fixed with the counter
shaft 15, the other gear on a side of the output shaft 16 of each
gear set of 17, 18, 19, 20 and 21 is installed free of rotation to
the output shaft 16, and is fixed separately with the output shaft
16 by coupling with the sleeve gear 22a, 22b or 22c.
[0031] An input shaft rotating speed sensor 23 is for detecting a
rotating speed of the input shaft 13, and an output shaft rotating
speed sensor 24 is for detecting a rotating speed of the output
shaft 16. Moreover, the electromagnetic clutch 2 controlled by the
control unit 4 generates a transmission torque proportional to its
exciting current, and transfers or cuts off power between the crank
shaft 1a of the internal combustion engine 1 and the input shaft 13
of the synchronous mesh-type automatic transmission 3.
[0032] An operation of the synchronous mesh-type automatic
transmission 3 controlled by the select and shift actuator 5 is
outlined in the configuration of FIG. 2. The select and shift
actuator 5 comprises a shift actuator 51 and a select actuator 54.
The select actuator 54 comprises a select motor 55 and a speed
reducer 56, and selects the sleeve gear 22a, 22b or 22c to be moved
by detecting a select position based on a signal of a select
position sensor 62.
[0033] The shift actuator 51 comprises a shift motor 52 and a speed
reducer 53, and shifts the selected sleeve gear 22a, 22b or 22 by
detecting a shift position based on a signal of a shift position
sensor 61. When the sleeve gear 22a is selected by the select
actuator 54, the shift actuator 51 shifts the sleeve gear 22a to
selectively couple with the primary gear set 14 or the 3.sup.rd
speed gear set 19. When the sleeve gear 22b is selected by the
select actuator 54, the shift actuator 51 shifts the sleeve gear
22b to selectively couple with the 2.sup.nd speed gear set 18 or
the 1.sup.st speed gear set 17. When the sleeve gear 22c is
selected by the select actuator 54, the shift actuator 51 shifts
the sleeve gear 22c to selectively couple with the reverse gear set
21 or the 5.sup.th speed gear set 20.
[0034] The gear set 17, 18, 19 and 20 respectively having a
different gear ratio are for advancing, and a configuration of
5-stage advancing with 1-stage reversing is shown as an example in
the embodiment 1. The sleeve gear 22a, 22b and 22c fix the gear
sets 17, 18, 19, 20 and 21 separately with the output shaft 16.
Namely, the sleeve gear 22a is installed between the primary gear
set 14 and the 3.sup.rd speed gear set 19, the sleeve gear 22b is
installed between the 1.sup.st speed gear set 17 and the 2.sup.nd
speed gear set 18, and the sleeve gear 22c is installed between the
5.sup.th speed gear set 20 and the reverse gear set 21. Next, any
one of the sleeve gear 22a 22b or 22c is selected by the select
actuator 54, and is transferred to its either side, wherein any one
of the 1.sup.st to the 5.sup.th speed gear for advancing, the
reverse gear or a neutral position is selected.
[0035] The operation of the synchronous mesh-type automatic
transmission 3 is to be explained more in detail referring again to
FIG. 2. In this FIG. 2 the synchronous mesh-type automatic
transmission 5 has three shift lines of LS1, LS2 and LS3 in a
vertical direction. A first shift line LS1 includes the 1.sup.st
speed position P1 for advancing in the upper end and the 2.sup.nd
speed position P2 for advancing in the bottom position, and the
corresponding speed position P1 and P3 are selected by the sleeve
gear 22b being transferred. A second shift line LS2 includes the
3.sup.rd speed position P3 and the 4.sup.TH speed position P4 for
advancing respectively in its upper end and in the bottom position,
and the corresponding speed position P3 and P4 are selected by the
sleeve gear 22a being transferred. Similarly, a third shift line
LS3 includes the 5.sup.th speed position P5 and the reverse speed
position PR respectively in the upper end and in the bottom
position, and the corresponding speed position P5 and PR are
selected by the sleeve gear 22c being transferred.
[0036] The select actuator 54 selects any one of the sleeve gear
22a, 22b and 22c by driving a select motor 55 and a speed reducer
56. In FIG. 2 an arrow SE shows a movable range and direction of
the select actuator 54, which selects any one of the first shift
line LS1, the second shift line LS2 and the third shift line LS3 by
moving in the movable range. After any one of the shift lines is
selected by the select actuator 54, the shift actuator 51 is
activated, wherein the shift actuator 51 transfers any one of the
sleeve gear 22a, 22b and 22c along any one of the shift line LS1,
LS2 and LS3 for selecting any one of the speed position required
from P1, P2, P3, P4, P5 and PR. In FIG. 2 an arrow SH shows a
movable range and direction of the shift actuator 51, and a neutral
line LN is assumed just in the middle of the movable range SH. The
neutral line NL includes a neutral position N12, N34 and N5R which
are respectively an intersection with the shift line LS1, LS2 and
LS3. At the neutral positions of N12, N34 and N5R, the sleeve gear
22a, 22b and 22c are located just in the middle of the gear set on
both sides without providing any speed positions.
[0037] Here, a case of the speed shift operation from the 2.sup.nd
to the 3.sup.rd speed position is picked up as an example for
explaining an operating process in the following. As the sleeve
gear 22b is in the 2.sup.nd speed position selected by the select
actuator 54, firstly the sleeve gear 22b is returned to the neutral
position N12, then the sleeve gear 22a is selected by the select
actuator 54 to be transferred to a side of the 3.sup.rd speed gear
set 19 by the shift actuator 51, and other sleeve gears excluding
22a are set to the neutral position. Additionally, in the
configuration shown in FIG. 1, the primary gear set 14 and the
output shaft 16 are to be coupled by the sleeve gear 22a when the
4.sup.th speed position is selected, and all sleeve gears 22a, 22b
and 22c do not link with any gear sets at the neutral
positions.
[0038] FIG. 3 is a configuration for explaining the speed shift
operation of the synchronous mesh-type automatic transmission 3
picked up from FIG. 1, wherein the 1.sup.st speed gear set 17, the
2.sup.nd speed gear set 18 and the sleeve gear 22b between the two
speed gear sets 17 and 18 are shown. In this FIG. 3, a 1.sup.st
speed gear 17a of the 1.sup.st speed gear set 17 is installed free
of rotation on a side of the output shaft 16, and a 2.sup.nd speed
gear 18a of the 2.sup.nd speed gear set 18 is also installed free
of rotation on the side of the output shaft 16. A synchronizer cone
17b and 18b are fixed respectively to the 1.sup.st speed gear 17a
and the 2.sup.nd speed gear 18a. A synchronizer ring 17c and 18c
are fixed free of rotation respectively to the synchronizer cone
17b and 18b, and transfer a friction torque respectively by
contacting with a surface of each cone pressed respectively by the
synchronizer cone 17b and 18b. A shift fork 25 is selected by the
select actuator 54, and moves along a shaft 26 toward the 1.sup.st
speed gear 17a or the 2.sup.nd speed gear 18a for transferring the
sleeve gear 22b to the 1.sup.st speed position or the 2.sup.nd
speed position, wherein a moving direction of the sleeve gear 22b
is indicated as an arrow A.
[0039] For example, when the 1.sup.st speed position is selected by
the select and shift actuator 5, the sleeve gear 22b is transferred
to the 1.sup.st speed position side by the shift fork 25, and is
coupling with the synchronizer ring 17c and the synchronizer cone
17b. Therefore, a rotation of the 1.sup.st speed gear 17a is
transferred to the output shaft 16 through the synchronizer cone
17b and the sleeve gear 22b. When a command to change a speed from
the 1.sup.st speed to the 2.sup.nd speed is generated, the shift
actuator 51 moves the shift fork 25 to the 2.sup.nd speed side, and
a coupling of the sleeve gear 22b and the synchronizer cone 17b is
released. Then, the sleeve gear 22b is transferred pressing the
synchronizer ring 18c to the synchronizer cone 18b after the sleeve
gear 22b is returned to the neutral position, and a coupling of the
sleeve gear 22b and the synchronizer cone 18b is made by letting
the 2.sup.nd speed gear 18a rotate in synchronizing with the output
shaft 16. The above mentioned operation is carried out with the
electromagnetic clutch 2 is disconnected, and the operation is
completed when the electromagnetic clutch 2 is connected after the
sleeve gear 22b and the synchronizer cone 18b are coupled.
[0040] FIG. 4 shows a relationship between a shift position and an
output voltage of the shift position sensor 61, and FIG. 5 shows a
relationship between a select position and an output voltage of the
select position sensor 62. The shift position sensor 61 outputs a
voltage VYA when the sleeve gear 22a, 22b and 22c are at the
1.sup.st, the 3.sup.rd or the 5.sup.th speed position respectively
indicated by P1, P3 and P5, and the voltage VYA becomes an aimed
position voltage during a shift control operation by the control
unit 4. A voltage VYB becomes the aimed position voltage when the
sleeve gear 22a, 22b and 22c are at the neutral position indicated
by N12, N34 and NSR. Similarly, a voltage VYC output by the shift
position sensor 61 becomes the aimed position voltage used by the
control unit 4 when the sleeve gear 22a,22b and 22c are at the
2.sup.nd, the 3.sup.rd or the reverse speed position respectively
indicated by P2. P4 and RP . . . Furthermore, the select position
sensor 62 generates a voltage VXC to be used as an aimed position
voltage when the sleeve gear 22c is selected for switching between
the 5.sup.th speed and the reverse speed position. In the same way,
a voltage VXB or a voltage VXA is output and used as the aimed
position voltage respectively according to when the sleeve gear 22a
is selected for switching between the 3.sup.rd and the 4.sup.th
speed position or when the sleeve gear 22b is selected for
switching between the 1.sup.st and the 2.sup.nd speed position.
[0041] The speed shift operation by the control unit 4 is executed,
wherein a position signal of a shift lever 12, a signal of the
accelerator position sensor 10, the rotating speed signals of the
input shaft rotating speed sensor 23 and the output shaft rotating
speed sensor 24, and a rotating speed signal of the internal
combustion engine are input to the control unit 4. Then, according
to these signals, the control unit 4 determines a transmission
stage suitable for the running conditions based on a stored shift
pattern program, and controls the shift and select actuator 5 while
detecting the shift and the select position by the shift and select
position sensor 6.
[0042] In tis operation, a power of the synchronous mesh-type
automatic transmission 3 is made to be off by cutting off the
exciting current of the electro-magnetic clutch 2, and as explained
in FIG. 3, the sleeve gear 22a, 22b or 22c is selected by giving an
operational command to the shift and select actuator 5 for coupling
a newly determined gear set after releasing a coupling of an old
gear set of the transmission stage, and the electromagnetic clutch
2 is reconnected when a completion of the new coupling is detected
from a signal of the shift and select position sensor 6. During the
operating process, an opening of the throttle 9 is decreased when
the electromagnetic clutch 2 is off, and at the re-coupling of the
electro-magnetic clutch 2, the opening of the throttle 9 is
increased to a predetermined position based on the rotating speed
of the internal combustion engine 1 and the signal of the output
shaft rotating speed sensor 24.
[0043] In the synchronous mesh-type automatic transmission control
device heretofore explained in the embodiment 1, the control unit 4
controls the speed shift position as is shown in the flowchart in
FIG. 7. Moreover, a case of an operation of shifting from the
2.sup.nd to the 3.sup.rd speed position is shown in this FIG. 7 as
an example. If the control unit 4 judges from the running condition
that the 3.sup.rd speed gear is more suitable while running with
the 2.sup.nd speed gear, whether or not the shift position is moved
to the neutral position N12 is firstly judged from whether or not a
shift position voltage of the shift position sensor 61 is equal to
VYB in step 701. If the shift position is not yet moved in step
701, the feed back control is executed for the shift position to be
moved to the neutral position N12 by repeating step 701. If the
shift position is moved to the neutral position N12, a process
advances to step 703, wherein whether or not the sleeve gear 22b
corresponding to the 3.sup.rd and 4.sup.th speed position is
selected by the select actuator 54 is judged based on detecting a
select position voltage VXB. In this case if the voltage VXB is
detected, the sleeve gear 22b of the transmission 3 is in a
selected state, wherein the sleeve gear 22b can be judged to be at
the neutral position N34 as a shift position voltage is equal to
VYB. the 3.sup.rd-4.sup.th speed position is selected by the select
actuator 54 from a detected position voltage of the select position
VXB.
[0044] If the 3.sup.rd-4.sup.th speed position is not selected by
the select actuator 54, a feedback control is made for the select
position to be transferred to the 3.sup.rd-4.sup.th speed position
in step 704, and the process returns to step 703. In this case, the
process advances to step 705 if the 3.sup.rd-4.sup.th speed
position is finished to be selected. In step 705, a shift drive
signal VYP1 is set for driving the shift actuator 51. In this
example, a signal level of the shift drive signal VYP1 is set equal
to that of a shift position voltage at the neutral position VYB. In
step 706 an updating value .alpha. of the shift drive signal VYP1
is determined from a rotating speed difference of the input shaft
rotating speed sensor 23 and the output shaft rotating speed sensor
24. The updating value .alpha. is set as shown in FIG. 6 for the
rotating speed difference of the input and the output shaft.
Namely, when a value of the rotating speed difference multiplied by
a gear ratio of the aimed shift position, which in this case is the
3.sup.rd speed position P3, is larger than a judging value .beta.,
the larger is the difference of the rotating speed, the larger the
updating value .alpha. becomes. Here, the judging value .beta. is
predetermined based on a detection error and a value of a dead band
of the rotating speed difference.
[0045] In step 707 the updating value a determined in step 706 is
added to the signal level of the shift drive signal VYP1 set up in
step 705, and a shift drive signal VYP2 is computed based on
(VYP1+.alpha.) as a new signal level. The shift drive signal VYP2
is delivered to the shift motor of the shift actuator 51, and this
signal is kept being delivered to the shift motor 52 until the
shift actuator 51 arrives at a position SHx a distance x apart from
the neutral position N34, wherein the distance x is equivalent to a
value of the shift drive signal VYP2 multiplied by a predetermined
time t0, VYP2Xto. The predetermined time t0 is a unit time, and is
obtained by equally dividing a required time T0 by a factor of M.
And the required time T0 is a time for the sleeve gear 22b to move
from the neutral position N34 to the aimed speed position, that is,
the 3.sup.rd speed position P3 in this case. Therefore, a fine
control in a gear change operation is achievable if a large value
of M is adopted. In step 708 whether or not a shift position has
reached the position SHx=VYP2t0 as the aimed shift position is
judged, and if this is not the case, a feedback control is repeated
in step 709. If this is the case, a value of the rotating speed
difference of the input and the output shaft multiplied by the gear
ratio of aimed shift position which is the 3.sup.rd speed position
P3, in this example, is compared with a judging value .gamma. in
step 710, and if the value is larger than .gamma., the updating
value .alpha. of the shift drive signal is reset by returning to
step 706 for repeating from step 706 to 710.
[0046] In steps from step 706 to 710 which is an operating process
from the neutral position N34 to the 3.sup.rd speed position P3,
firstly the updating value .alpha. of the shift drive signal VYP1
is determined, wherein the shift drive signal VYP1 is a shift drive
signal from the neutral position N34 to the position SHx a distance
x apart from the neutral position N34 toward the 3.sup.rd speed
position P3, and the shift drive signal VYP2 corresponding to the
position SHx is set. Then, the transfer operation is carried out to
move the sleeve gear 22b to the position SHx based on the shift
drive signal VYP2. As above mentioned, the position SHx is a moving
distance of the sleeve gear 22b in the unit time to, and the
smaller is the unit time t0, the more finely the shift control is
executed. Every time the distance x is moved, the updating value a
is newly determined, and the shift drive signal VYP2 is computed
based on the updating value .alpha.. As is shown in FIG. 6, the
larger is the rotating speed difference of the input and the output
shaft, the larger the updating value .alpha. becomes, and also the
larger the level of the shift drive signal VYP2 becomes.
Accordingly, a transfer speed or operating speed of the sleeve gear
22a by the shift fork 25 becomes faster. By repeating steps from
step 706 to 710, the sleeve gear 22a is transferred with a fast
speed. In this transfer, when the synchronizer ring being pressed
by the sleeve gear 22a comes in contact with the synchronizer cone,
the synchronizing mechanism begins to work and the rotating speed
difference of the input and the output shaft becomes smaller.
Therefore, the updating value .alpha. also becomes smaller, and the
meshing of the sleeve gear and the synchronizer cone is done. Thus,
the updating value .alpha. becomes o and the shift operation comes
to a halt when the rotating speed difference of the output and the
input shaft becomes no larger than .beta..
[0047] Namely, the transfer speed or operating speed of the sleeve
gear is fast when it starts the neutral position, and the sleeve
gear begins a synchronizing rotation faster with pressing the
synchronizer ring to the synchronizer cone. And once the
synchronous rotation begins, the transfer speed or operating speed
becomes smaller, thus a shock of a frictional transfer from the
synchronizer ring and coupling at meshing with the synchronizer
cone is alleviated. The judging value .gamma. in step 710 is a
value for judging whether or not the speed shift operation is made
to a predetermined position, and when a value of the rotating speed
difference multiplied by the gear ratio of the aimed shift
position, namely the 3.sup.rd speed position P3, becomes smaller
than the judging value .gamma., it is judged that the shift
operation to the predetermined position is completed, and a step
advances to step 711. In step 711 whether or not the shift position
has become the 3.sup.rd speed position is judged from whether or
not an output of the shift position sensor 61 is equal to VYA And
if this is not the case, a process advances to step 712, wherein
the feedback control with VYA as the aimed position is continued
for returning to step 711 until the shift position becomes VYA, and
the speed shift operation is completed.
[0048] A process of the speed shift operation heretofore explained
as an example is similarly applicable to other cases such that when
any one of the sleeve gear 22a, 22b and 22c is transferred from the
neutral position N12, N34 or N5R to the speed position P1, P2, P3,
P4, P5 or PR. In this shift operation of the sleeve gears, the
larger the difference is the rotating speed difference of the input
and the output shaft, the faster the transfer speed of the sleeve
gears become, and the speed is slowed down when the synchronizing
mechanism begins to function. Thus, a time required till the
synchronizing rotation is completed is shortened, and resultantly a
shock to the synchronizer rings, the synchronizer cones and the
sleeve gears is capable of being minimized.
* * * * *