U.S. patent application number 09/780666 was filed with the patent office on 2001-08-09 for synchronizer.
This patent application is currently assigned to EATON CORPORATION. Invention is credited to Jackson, Graeme Andrew, Smith, Carl Christopher John.
Application Number | 20010011624 09/780666 |
Document ID | / |
Family ID | 10865849 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010011624 |
Kind Code |
A1 |
Jackson, Graeme Andrew ; et
al. |
August 9, 2001 |
Synchronizer
Abstract
A baulkring-type synchronizer (18) includes cone clutch friction
surfaces (24,48 and 26,50) and jaw clutch teeth (36b,28 and 36c,30)
for frictionally synchronizing and positive connecting gears
(14,16) to a shaft (12). A plurality of rigid members (72) is
drivingly interposed between blocker teeth (44,46) affixed to
baulkrings (40,42) and self-energizing ramp surfaces (71a, 71b,
73a, 73b) on self-energizing members (70,72) mounted on an outer
circumference of a hub 32 affixed to the shaft (12). A shift sleeve
(34) is slidably splined to the hub (32) and is moved by an
operator shift force (F.sub.o) and an additive force (F.sub.a)
provided by the self-energizing ramp surfaces. Both forces (F.sub.o
and F.sub.a) react against the blocker teeth to engage the friction
surfaces. The self-energizing members (70,72) are slidable relative
to the hub and are axially centered resiliently on the hub by
detent assemblies (76,78).
Inventors: |
Jackson, Graeme Andrew;
(Lancashire, GB) ; Smith, Carl Christopher John;
(Lancashire, GB) |
Correspondence
Address: |
Howard D. Gordon
Patent Law Department
Eaton Center
1111 Superior Avenue
Cleveland
OH
44114-2584
US
|
Assignee: |
EATON CORPORATION
|
Family ID: |
10865849 |
Appl. No.: |
09/780666 |
Filed: |
December 8, 2000 |
Current U.S.
Class: |
192/53.31 ;
192/53.34; 74/339 |
Current CPC
Class: |
Y10T 74/19284 20150115;
F16D 2023/065 20130101; F16D 2023/0618 20130101; F16D 23/06
20130101 |
Class at
Publication: |
192/53.31 ;
192/53.34; 74/339 |
International
Class: |
F16D 023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 1999 |
GB |
9928891.2 |
Claims
What is claimed is:
1. A synchronizer for frictionally synchronizing and positive
connecting first and second drives disposed for relative rotation
about a common axis; the synchronizer comprising: a first element
affixed against rotation and axial movement relative to the first
drive and having an annular periphery with external splines: a
second element including an annular periphery with internal splines
defining first jaw means and axially movable from a neutral
position to an engaged position with second jaw means for positive
connecting the drives in response to engaging movement of the
second element by an axially directed first shift force (F.sub.o),
the second element including internal splines mating continuously
with the external splines in close slidable relation for preventing
relative rotation therebetween between; a first ring including a
first friction surface axially movable into engagement with a
second friction surface in response to the engaging movement of the
second element for producing a synchronizing torque (T.sub.o);
first and second pluralities of blocker surfaces movable into
engagement in response to the engaging movement of the second
element and an asynchronous rotation between the first and second
drives in one direction for preventing asynchronous engagement of
the jaw means and for transmitting the first shift force (F.sub.o)
to the first friction surface to effect an engagement force of the
friction surfaces, the second plurality of blocker surfaces affixed
to the first ring; pluralities of first and second self-energizing
means respectively including first and second ramps operative when
engaged to react the synchronizing torque for producing an additive
axial force (F.sub.a) in the direction of the first shift force
(F.sub.o) and for increasing the engagement force of the friction
surfaces, one of the first and second self-energizing means
including means for directing the additive axial force (F.sub.a) to
the first friction surface via the blocker surfaces, each first
self-energizing means mounted on one of the elements, and each
second self-energizing means mounted for non-radial movement and
limited rotation relative to another of the elements; characterized
by: resilient means for limiting the additive axial force to a
first predetermined amount; and each first self-energizing means
including a first member movably mounted on the one of the elements
and defining one of the first self-energizing ramps, and the first
member movable against the resilient means in response to the
additive axial force (F.sub.a) exceeding the first predetermined
amount.
2. The synchronizer of claim 1, wherein: the periphery of the first
element including axially extending first recesses each slidably
receiving one of the first members for axial movement against the
resilient means from a first position in a direction opposite the
shift force (F.sub.o) applied to the second element in response to
the additive axial force (F.sub.a) produced by the engaged ramps
exceeding the predetermined amount in the direction of the shift
force (F.sub.o) applied to the second element.
3. The synchronizer of claim 2, wherein: a radially inward facing
surface of each first member includes a curved centering surface
acted by the resilient means for positioning the first member in
the first position and operative to move the resilient means
radially inward in response to the additive axial force (F.sub.a)
exceeding the first predetermined amount.
4. The synchronizer of claim 3, further including: fifth and sixth
pluralities of blocker surfaces movable into engagement in response
to the engaging movement of the second element and an asynchronous
rotation between the first and second drives in a direction
opposite the one direction for preventing asynchronous engagement
of the jaw means and for transmitting the first shift force
(F.sub.o) to the first friction surface to effect an engagement
force of the friction surfaces, the sixth plurality of blocker
surfaces affixed to the first ring; pluralities of third and fourth
self-energizing means respectively including fifth and sixth ramps
operative when engaged to react the synchronizing torque for
producing a third additive axial force (F.sub.a) in the direction
of the first shift force (F.sub.o) and for increasing the
engagement force of the friction surfaces, one of the third and
fourth self-energizing means including means for directing the
third additive axial force (F.sub.a) to the first friction surface
via the fifth and sixth pluralities of blocker surfaces, each third
self-energizing means mounted on one of the elements, and each
fourth self-energizing means mounted for non-radial movement and
limited rotation relative to another of the elements; second
resilient means for limiting the additive axial force of third and
fourth self-energizing means to a third predetermined amount; and
each third self-energizing means including a second member movably
mounted on the one of the elements at a position circumferentially
spaced from the first member and defining one of the fifth
self-energizing ramps, the second member movable against the
resilient means in response to the third additive axial force
(F.sub.a) exceeding the third predetermined amount, and a
circumferentially extending member rigidly securing the second and
fourth self-energizing means together circumferentially between the
first and second members.
5. The synchronizer of claim 4, wherein: the periphery of the first
element including axially extending second recesses each slidably
receiving one of the second members for axial movement against the
second resilient means from a first position in a direction
opposite the shift force (F.sub.o) applied to the second element in
response to the third additive axial force (F.sub.a) produced by
the engaged ramps exceeding the third predetermined amount in the
direction of the shift force (F.sub.o) applied to the second
element.
6. The synchronizer of claim 5, wherein: a radially inwardly facing
surface of each second member includes a curved centering surface
acted by the resilient means for positioning the second members in
the first positions and operative to move the resilient means
radially inwardly in response to the additive axial forces
(F.sub.a) exceeding the third predetermined amount.
7. The synchronizer of 6 claim, wherein: the first element is a
hub, the second element is a shift sleeve, the first ring is a
baulkring having the second pluralities of blocker surfaces affixed
thereto, the second self-energizing means includes the means for
directing the additive axial force (F.sub.a) to the first friction
surface via the blocker surfaces, the first self-energizing means
are mounted on the hub, and the second self-energizing means are
mounted for non-radial movement and non-axial movement relative to
the shift sleeve and for limited rotation relative to the shift
sleeve.
8. The synchronizer of claim 1, further including: a third drive
disposed for rotation about the common axis relative to the first
and second drives and axially spaced from the second drive; the
second element internal splines defining third jaw means axially
movable from a neutral position to an engaged position with fourth
jaw means for positive connecting the first and third drives in
response to engaging movement of the second element by an axially
directed second shift force (F.sub.o); a second ring including a
third friction surface axially movable into engagement with a
fourth friction surface in response to the engaging movement of the
second element by the second shift force (F.sub.o) for producing a
synchronizing torque (T.sub.o); third and fourth pluralities of
blocker surfaces movable into engagement in response to the
engaging movement of the second element by the second shift force
(F.sub.o) for preventing asynchronous engagement of the third and
fourth jaw means and for transmitting the second shift force
(F.sub.o) to the third friction surface to effect an engagement
force of the third and fourth friction surfaces, the fourth
plurality of blocker surfaces affixed to the second ring; the
pluralities of first and second self-energizing means respectively
including third and fourth ramps operative when engaged to react
the synchronizing torque for producing a second additive axial
force (F.sub.a) in the direction of the second shift force
(F.sub.o) and for increasing the engagement force of the third and
fourth friction surfaces, one of the first and second
self-energizing means including means for directing the second
additive axial force (F.sub.a) to the third friction surface via
the third and fourth blocker surfaces, and each first member
defining one of the third self-energizing ramps and the first
member movable against the resilient means in response to the
second additive axial force (F.sub.a) exceeding a second
predetermined amount.
9. The synchronizer of claim 8, wherein: the periphery of the first
element including axially extending recesses each slidably
receiving one of the first members for axial movement against the
resilient means from a first position in a direction opposite the
shift force (F.sub.o) applied to the second element in response to
the additive axial force (F.sub.a) produced by the engaged ramps
exceeding either of the first and second predetermined amount in
the direction of the shift force (F.sub.o) applied to the second
element.
10. The synchronizer of claim 9, wherein: a radially inward facing
surface of each first member includes a curved centering surface
acted by the resilient means for positioning the first member in
the first position and operative to move the resilient means
radially inward in response to the additive axial force (F.sub.a)
exceeding the either of the first and second predetermined
amount.
11. The synchronizer of claim 10, further including: fifth and
sixth pluralities of blocker surfaces movable into engagement in
response to the engaging movement of the second element and an
asynchronous rotation between the first and second drives in a
direction opposite the one direction for preventing asynchronous
engagement of the jaw means and for transmitting the first shift
force (F.sub.o) to the first friction surface to effect an
engagement force of the friction surfaces, the sixth plurality of
blocker surfaces affixed to the first ring; pluralities of third
and fourth self-energizing means respectively including fifth and
sixth ramps operative when engaged to react the synchronizing
torque for producing a third additive axial force (F.sub.a) in the
direction of the first shift force (F.sub.o) and for increasing the
engagement force of the friction surfaces, one of the third and
fourth self-energizing means including means for directing the
third additive axial force (F.sub.a) to the first friction surface
via the fifth and sixth pluralities of blocker surfaces, each third
self-energizing means mounted on one of the elements, and each
fourth self-energizing means mounted for non-radial movement and
limited rotation relative to another of the elements; second
resilient means for limiting the additive axial force of the third
and fourth self-energizing means to a third predetermined amount;
and each third self-energizing means including a second member
movably mounted on the one of the elements at a position
circumferentially spaced from the first member and defining one of
the fifth self-energizing ramps, the second member movable against
the resilient means in response to the third additive axial force
(F.sub.a) exceeding the third predetermined amount, and a
circumferentially extending member rigidly securing the second and
fourth self-energizing means together circumferentially between the
first and second members.
12. The synchronizer of claim 10, further including: seventh and
eighth pluralities of blocker surfaces movable into engagement in
response to the engaging movement of the second element by the
second shift force (F.sub.o) for preventing asynchronous engagement
of the third and fourth jaw means and for transmitting the second
shift force (F.sub.o) to the third friction surface to effect an
engagement force of the third and fourth friction surfaces, the
eighth plurality of blocker surfaces affixed to the second ring;
and the pluralities of third and fourth self-energizing means
respectively including seventh and eighth ramps operative when
engaged to react the synchronizing torque for producing a fourth
additive axial force (F.sub.a) in the direction of the second shift
force (F.sub.o) and for increasing the engagement force of the
third and fourth friction surfaces, one of the third and fourth
self-energizing means including means for directing the fourth
additive axial force (F.sub.a) to the third friction surface via
the seventh and eighth blocker surfaces, and each second member
defining one of the seventh self-energizing ramps and the second
member movable against the second resilient means in response to
the fourth additive axial force (F.sub.a) exceeding a fourth
predetermined amount.
13. The synchronizer of claim 12, wherein: the periphery of the
first element including axially extending second recesses each
slidably receiving one of the second members for axial movement
against the second resilient means from a first position in a
direction opposite the shift force (F.sub.o) applied to the second
element in response to the fourth additive axial force (F.sub.a)
produced by the engaged ramps exceeding the fourth predetermined
amount in the direction of the shift force (F.sub.o) applied to the
second element.
14. The synchronizer of claim 13, wherein: a radially inwardly
facing surface of each second member includes a curved centering
surface acted by the second resilient means for positioning the
second members in the first positions and operative to move the
second resilient means radially inwardly in response to additive
axial forces (F.sub.a) exceeding either of the third and fourth
predetermined amounts.
15. The synchronizer of claim 14, wherein: the first element is a
hub, the second element is a shift sleeve, the first and second
rings are first and second, the second self-energizing means
includes the means for directing the first and second additive
axial force (F.sub.a), the fourth self-energizing means includes
the means for directing the third and fourth additive axial force
(F.sub.a), the first and third self-energizing means are mounted on
the hub, and the second and fourth self-energizing means are
mounted for non-radial movement and non-axial movement relative to
the shift sleeve and for limited rotation relative to the shift
sleeve.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a synchronizer having
self-energizing and means to limit force provided by the
self-energizing means.
BACKGROUND OF THE INVENTION
[0002] Synchronizers for use in multi-ratio transmissions are well
known. Such synchronizers include pairs of friction and jaw members
for respectively synchronizing and positive clutching a gear to a
shaft, pre-energizer assemblies for engaging the friction members
in response to initial engaging movement of a shift sleeve, a hub
rotatably fixed to the shaft and having external spline teeth
slidably receiving internal spline teeth of the shift sleeve which
often defines one of the jaw member pairs, a baulkring having
blocker teeth for arresting engaging movement of the shift sleeve
until synchronization is reached and for transferring a shift force
from the sleeve to increase the engaging force of the friction
members.
[0003] It is also known that such synchronizers may be used to
reduce shift time and shift effort required by a vehicle operator
by providing the synchronizes with self-energizing means and that
springs may be used to limit forces provided by the self-energizing
means. U.S. Pat. No. 5,678,670 discloses a synchronizer having all
of the above features and U.S. Pat. No. 5,544,727 discloses all but
the spring regulating feature.
SUMMARY OF THE INVENTION
[0004] An object of this invention is to provide a synchronizer
with self-energizing and improved force limiting of the
self-energizing.
[0005] The invention relates to a synchronizer, as disclosed in
U.S. Pat. No. 5,544,727 which represents the precharacterizing part
of claim. The synchronizer frictionally synchronizes and positive
connects first and second drives disposed for relative rotation
about a common axis, and the synchronizer comprises: A first
element affixed against rotation and axial movement relative to the
first drive and has an annular periphery with external splines. A
second element includes an annular periphery with internal splines
defining firstjaw means and axially movable from a neutral position
to an engaged position with second jaw means for positive
connecting the drives in response to engaging movement of the
second element by an axially directed first shift force (F.sub.o).
The second element includes internal splines mating continuously
with the external splines in close slidably relation for preventing
relative rotation therebetween between. A first ring includes a
first friction surface axially movable into engagement with a
second friction surface in response to the engaging movement of the
second element for producing a synchronizing torque (T.sub.o).
First and second pluralities of blocker surfaces are movable into
engagement in response to the engaging movement of the second
element for preventing asynchronous engagement of the jaw means and
for transmitting the first shift force (F.sub.o) to the first
friction surface to effect an engagement force of the friction
surfaces. The second plurality of blocker surfaces are affixed to
the first ring. Pluralities of first and second self-energizing
means respectively include first and second ramps operative when
engaged to react the synchronizing torque for producing an additive
axial force (F.sub.a) in the direction of the first shift force
(F.sub.o) and for increasing the engagement force of the friction
surfaces. One of the first and second self-energizing means
includes means for directing the additive axial force (F.sub.a) to
the first friction surface via the blocker surfaces. Each of the
first self-energizing means are mounted on one of the elements and
each of the second self-energizing means are mounted for non-radial
movement and limited rotation relative to another of the
elements.
[0006] The improvement is characterized by resilient means for
limiting the additive axial force to a predetermined amount. Each
of the first self-energizing means including a member movably
mounted on the one of the elements and defining one of the first
self-energizing ramps. The member is movable against the resilient
means in response to the additive axial force (F.sub.a) exceeding
the predetermined amount.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The synchronizer of the invention is shown in the
accompanying drawings in which:
[0008] FIG. 1 is a sectional view of a double-acting baulkring-type
synchronizer in a neutral position and disposed for rotation about
the axis of a shaft;
[0009] FIGS. 2 and 3 are relief views of broken away portions of
components in FIG. 1 looking axially relative to the shaft;
[0010] FIG. 4 is a vertical sectional view of a circled assembly in
FIG. 3.
[0011] FIG. 5 is a relief view of a shift sleeve of the
synchronizer in FIG. 1, and with components in FIGS. 5 and 6
rotated 60 degrees relative to FIG. 1;
[0012] FIG. 6 is the assembled components of FIG. 1 in the neutral
position with the shift sleeve of FIG. 5 removed;
[0013] FIG. 7 is a perspective view of a self-energizing member in
FIGS. 1 and 6.
[0014] FIGS. 8 and 9 are partial views of FIG. 6 with components
therein in two different engaged positions; and
[0015] FIG. 10 is a sectional view of a self-energizing member in
FIG. 4 looking along line a-a.
DETAILED DESCRIPTION OF THE DRAWINGS
[0016] The term "synchronizer" shall designate a clutch mechanism
utilized to non-rotatably couple a selected ratio gear to a shaft
by means of a positive clutch in which attempted engagement of the
positive clutch is prevented until members of the positive clutch
are brought to substantially synchronous rotation by a
synchronizing friction clutch associated with the positive clutch.
The term "self-energizing" shall designate a synchronizer which
includes ramps or cams or the like to increase the engaging force
of the synchronizing proportion to the synchronizing torque of the
friction clutch.
[0017] Looking now at FIGS. 1-10, therein is shown a gear and
synchronizer assembly 10 is which forms part of a multi-ratio
change speed transmission. Assembly 10 includes a shaft 12 mounted
for rotation about a central axis 12a, axially spaced apart gears
14,16 supported on the shaft for rotation relative thereto and
secured against axial movement relative to the shaft in known
manner, and a double-acting synchronizer 18.
[0018] The synchronizer 18 includes annular members 20,22 axially
and rotatably affixed to gears 14,16 in known manner, gear friction
surfaces 24,26 herein integral with members 20,22, gear jaw teeth
28,30 herein integral with members 20,22, a hub member 32 axially
and rotatably affixed at a central opening 32a thereof to shaft 12,
a shift sleeve 34, internal spline teeth 36 defined on a central
opening of sleeve 34 and in constant mesh with external spline
teeth 38 defined on the outer circumference of hub 32, baulkrings
40,42, blocker teeth sets 44,46 and friction surfaces 48,50 herein
integral with baulkrings 40,42, pre-energizer assemblies 52, and a
self-energizing/blocker assembly 54. Herein, the synchronizer
includes three circumferentially spaced apart
self-energizing/blocker assemblies 54 which cooperate with a like
number of blocker teeth on each baulkring, and three
circumferentially spaced apart pre-energizer assemblies. Each
blocker tooth 44,46 respectively includes angled blocker surfaces
44a, 44b, 46a, 46b.
[0019] As is readily seen, friction surfaces 24,48 and 26,50 pair
up to define friction clutches for synchronizing the gears to the
shaft prior to engagement of the jaw clutch members. Cone clutches
are preferred; however, other types of friction clutches may be
used. The friction surfaces may be defined by any of several known
friction materials affixed to the base member, e.g., pyrolytic
carbon friction materials such as disclosed in U.S. Pat. Nos.
4,700,823; 4,844,218 and 4,778,548 may be used.
[0020] Spline teeth 36,38 have axially extending flank surfaces
36a,38a which continuously mate in close sliding relation so that
there is relatively no free play between shift sleeve 34 and shaft
12. Opposite ends of splines 36 define jaw teeth 36b,36c which
respectively mate with gear teeth 28,30 to positive clutch the
gears to the shaft. The flank sides of jaw teeth 36b,36c and of
gear jaw teeth 28,30 may be provided with an antibackout or a
locking angle feature to prevent inadvertent disengagement of the
teeth. Details of this feature may be seen by reference to U.S.
Pat. No. 4,727,968.
[0021] Each pre-energizer assembly 52 includes a helical
compression spring 58 and plunger 60 disposed in a radially
extending blind bore in hub 32 and biasing a roller or ball 62
(herein a roller) into an annular detent groove 36d in shift sleeve
splines 36. Pre-energizer assembly 52 resiliently positions shift
sleeve 34 in the neutral position shown in FIG. 1. Rollers 62 are
axially spaced between abutment surfaces 64a,66a of a plurality of
tabs 64,66 (herein three) formed integral with baulkrings 40,42.
The tabs extend into recesses 32b in hub 32 for limiting rotation
of the baulkring relative to the hub and shaft.
[0022] When it is desired to couple either gear to the shaft, an
appropriate and unshown shift mechanism, such as disclosed in U.S.
Pat. No. 4,920,815, moves shift sleeve 34 axially via a partially
shown shift fork 68 along the axis of shaft 12 either left to
couple gear 14 or right to couple gear 16. The shift mechanism may
be manually moved by an operator through a linkage system, may be
selectively moved by an actuator, or may be moved by means which
automatically initiate shift mechanism movement and which also
controls the magnitude of the force applied by the shift mechanism.
When the shift mechanism is manually moved, pre-energizer
assemblies apply a pre-energizer force proportional to the force
applied by the operator to the shift sleeve. Whether manually or
automatically applied, the force is applied to the shift sleeve in
an axial direction and is proportional to a shift force hereinafter
referred to as an operator shift force F.sub.o. The pre-energizer
force, depending on direction of shift sleeve movement by the shift
force (F.sub.o), moves either friction surface 48 or 50 into
initial engagement with its associated friction surface to clock
the associated baulkring to a position relative to hub 32 for
positioning the self-energizing/blocker assemblies 54 in a manner
explained hereinafter.
[0023] The self-energizing/blocker assemblies 54 each include
self-energizing members 70,72, the blocker teeth 44,46, a rigid
self-energizing/blocker member 74 which reacts self-energizing and
blocker forces, and detent assemblies 76,78 respectively biasing
members 70,72 to the positions of FIG. 7. Assemblies 76,78 are
identical; hence, only assemble 76 is described in detail. Assembly
76 includes a round headed detent member 80 biased into a detent
groove 70a in member 70 by a compression spring 82 disposed in a
blind bore 32c in the hub. Member 70 is slidably disposed in a slot
having axially extending sidewalls 32d,32e that diverge as they
extend radially inward for slidably embracing like diverging
sidewalls 70b,70c of member 70. The sidewalls prevent radially
outward movement of member 70. Detent groove 70 include detent
ramps 70d,70e which prevent axial movement of member 70 until axial
forces acting on self-energizing or boost ramps 71a,71b of member
70 exceed a predetermined centering force provided by spring 81,
and the curved centering surface defined by groove 70a and detent
ramps 70d,70e. To prevent interference of member 70 sidewalls with
baulkrings 40,42, when member 70 moves axially as seen in FIG. 9,
portions of axial ends of sidewalls 70b,70c are removed in a manner
seen in FIG. 10 for sidewall 70b.
[0024] Rigid member 74 includes circumferentially spaced apart end
portions 82,84 rigidly secured together by a circumferentially
extending portion 86 received in a circumferentially extending slot
34a in shift sleeve 34. Slot 34a allows limited circumferential
movement of member 74 therein relative to the sleeve and prevents
axial movement herein relative to the sleeve. End portion 82
includes self-energizing ramp surfaces 82a,82b which respectively
react against self-energizing ramp surfaces 71a,71b when shift
sleeve 34 is moved axially left or right and blocker surfaces
82c,82d which respectively react against blocker surfaces 44a,46a
of blocker teeth 44,46. In a like manner, end portion 84 includes
self-energizing ramp surfaces 84a,84b for respectively reacting
against self-energizing ramp surfaces 73a,73b and blocker surfaces
84c,84d which respectively react against blocker surfaces 44b,46b.
Non-self-energizing ramp surfaces 82e,84e respectively react
against surfaces 71c,73c when the synchronizer is in the neutral
position of FIGS. 1 and 6. The engaged position of the
non-self-energizing surfaces prevents unwanted activation of the
self-energizing ramp surfaces in the event there is some amount of
torque produced by one of the cone clutches, e.g., viscous shear of
oil between the cone clutch friction surfaces may produce a torque
that could otherwise activate the ramps.
[0025] Function of self-energizing/blocker assemblies 76 is
described relative to FIGS. 1 and 6-9. The description assumes an
asynchronous condition in one direction exists between shaft 12 and
gear 16. When the blocker and self-energizing ramp surfaces are
engaged as shown in FIG. 8 friction surfaces 50,26 are also
engaged. Axial extensions 44c,46c of blocker teeth 44,46 keep the
blocker teeth circumferentially positioned between end portions
82,84. Asynchronous conditions in the other direction or for gear
14 produce surface engagements that should be obvious from the
following description. FIG. 6 illustrates a "neutral position" of
all synchronizer components. Initial rightward axial movement of
shift sleeve 34 by the operator shift force F.sub.o is transmitted
by pre-energizer rollers 62 to baulkring 42 via tab abutment
surfaces 66a to effect initial frictional engagement of movable
cone surface 50 with gear cone surface 26, thereby producing an
initial synchronizing torque for rotating blocker surfaces 46a to
positions ensuring contact with blocker surfaces 82e. The initial
rightward movement also moves rigid member 74 enough for
non-self-energizing ramp surfaces 71c, 82e to axially disengage and
allow the initial synchronizing torque to engage blocker surfaces
82b,46a, as seen in FIG. 8. The initial engagement force of the
cone surface is, of course, a function of the force of spring 58
and the angles of the walls of detent grooves 36d. In the
"blocking/self-energizing position" of FIG. 8, the torque has
rotated baulkring 42 and rigid members 74 enough to also engage
self-energizing ramp surfaces 71b,82b. Hence, in FIG. 8 surfaces
82e,82b are trapped between baulkring blocker surfaces 46a and
self-energizing ramp surfaces 71b. When these surfaces are so
trapped and ignoring the effect of the engaged self-energizing ramp
surfaces 82b,71b, full operator shift force F.sub.o applied to
rigid member 74 from shift sleeve 34 is transmitted across blocker
surfaces 82d,46a, thereby engaging friction surfaces 26,50 with the
operator shift force F.sub.o for producing a synchronizing torque
T.sub.o proportional to the operator shift force F.sub.o. Since
blocker surfaces 82d,46a are oblique to the plane of rotation, they
in addition to preventing asynchronous engagement of jaw teeth
36a,30 and transmitting the shift force F.sub.o to friction
surfaces 26,50, also produce a counter torque or unblocking torque
counter to the synchronizing torque but of lesser magnitude during
asynchronous conditions. As substantial synchronism is reached, the
synchronizing torque drops below the unblocking torque, whereby the
blocker teeth move out of engagement to allow continued axial
movement of the shift sleeve and engagement of movable jaw teeth
36c with gear jaw teeth 30.
[0026] Looking now at the affects of the self-energizing ramp
surfaces and the detent assemblies 76, the synchronizing torque
T.sub.o due to the operator applied axial shift force F.sub.o is,
of course, reacted across the self-energizing ramp surfaces, which
surfaces produce an axial force component or axial additive force
F.sub.a acting on the end portion 82 in the same direction as
operator shift force F.sub.o. This additive force F.sub.a is also
transmitted across the blocker surfaces, thereby further increasing
the engaging force of the friction surfaces to provide an additive
synchronizing torque T.sub.a which adds to the torque T.sub.o.
[0027] In the event that the self-energizing additive axial force
F.sub.a exceeds a predetermined amount, as determined by detent
assemblies 76, member 70 will move leftward, as shown in FIG. 9,
and allow non-self-energizing surfaces 82e to move into balance
positions. When in the balance positions, self-energizing ramp
surfaces 82b,71b are engaged and non-self-energizing surfaces 82e
engage axially extending surface portions 32f of sidewall 32d in
hub 32 which do not produce an axial additive force component. When
in this position, the maximum additive force F.sub.a is limited to
the force reacted by the detent assemblies 76 at the balance
position since any synchronizing torque increase will be reacted by
the non-self-energizing surfaces 82c,32f.
[0028] The predetermined amounted of axial force provided by the
detent assemblies 76,78 may be different for gears 14,16 and for up
and down shifts by varying the angles of the detent ramps 70d,70e
in each of members 70,72.
[0029] A synchronizer with self-energizing has been disclosed. The
following claims are intended to cover the inventive portions of
the disclosed synchronizer.
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