LOCKING DIFFERENTIAL HAVING
DAMPENING COMMUNICATION SPRING
This application is being filed on 26 August 2013, as a PCT
International Patent application and claims priority to U.S. Patent Application Serial
No. 611694,479 filed on 29 August 2012, the disclosure of which is incorporated
herein by reference in its entirety.
BACKGROUND
5 I . Field Teachings
The present teachings relate generally to locking differentials for vehicles
and, more specifically, to features of a locking differential having a dampening
communication spring.
2. Descriution of the Related Art
10 Locking differentials of the type contemplated by the present teachings
are employed as a part of a drive train and generally include a pair of clutch members
supported for rotation in a housing. A pair of side gears are splined for rotation to
corresponding axle half shafts. A clutch mechanism is interposed between the clutch
members and the side gears. A cross pin is operatively mounted for rotation with the
15 housing and is received in a pair of opposed grooves formed on the inwardly facing
surfaces of the clutch members. In an event requiring differential rotation between the
axle half shafts, such as cornering, the higher speed axle shaft advances its clutch to an
over-running condition, decoupling it from the powertrain torque. Ifthe driving terrain
provides insufficient traction to activate the over-running feature of the differential, or
20 while driving in a straight line, torque is applied equally to both axle shafts.
While locking differentials of this type have generally worked for their
intended purposes, certain disadvantages remain. More specifically, the interaction of
the clutch members. There are currently mechanical limiters on the interaction.
However, these limiters do not prevent erratic motion within the mechanical travel
25 limits. As a result, rougher operation and increased noise may occur. In addition,
feedback to the clutch members from the differential carrier is limited to the influence
of the preloaded clutch member geometry and force interface with the cross pin.
Thus, there remains a need in the art for a locking differential that is
designed so as to achieve control of the interaction of the clutch members, thereby
5 providing for smoother operation and reduced noise.
SUMMARY
The present teachings include a locking differential for a vehicle
including a rotatable housing and a differential mechanism supported in the housing.
10 The housing is rotatable about an axis of rotation. The differential mechanism includes
a pair of clutch members disposed in spaced axial relationship with respect to one
another along the axis of rotation. A pair of side gears is operatively adapted for
rotation about the axis of rotation about the axis of rotation with a corresponding pair of
axle half shafts. A pair of clutch mechanisms is operable for transferring torque
15 between corresponding clutch members and the side gears when actuated. The clutch
members are axially moveable within the housing along the axis of rotation to actuate a
respective clutch mechanism. Each of the clutch members presents an inwardly
directed face. Each face includes a groove disposed in facing relationship with respect
to the other. A cross pin is received in the grooves and operatively connected for
20 rotation with the housing about the axis of rotation. A dampening communication
spring is disposed over an outer circumference of the clutch members and cooperates
with the cross pin to control interaction of the clutch members.
In one aspect of the present teachings, during normal, non-differentiated
movement between the axle half shafts, such as when a vehicle is driving in a straight
25 path down a road, the line contact is more than sufficient to transfer torque between the
cross pin and the clutch members because all the components rotate together. However,
in the event of differential movement between one or the other of the axle half shaft and
its associated side gear, the binding force generated by the preloaded clutch mechanism
causes the clutch member to advance in rotation, relative to the cross pin. This action
30 causes the cross pin to re-center in the groove per the interlock limitations, and allows
the clutch mechanism to rotate with a binding force under the threshold required to
transmit torque between the clutch member and the side gear. By applyingadampening
communication spring between the clutch members and cooperating with the cross pin,
varying degrees of control of the interaction of the clutch members may be achieved.
The dampening communication spring can positively influence or even prevent erratic
motion within the mechanical travel limits. The dampening communication spring
provides for smoother operation and reduced noise. The dampening communication
5 spring also provides feedback to the differential clutch members from the differential
carrier. This results in ultimate control of the dampening back to the driveline.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects ofthe present teachings will be readily appreciated, as the
same becomes better understood after reading the subsequent description taken in
10 connection with the accompanying drawings wherein:
Figure 1 is a schematic cross-sectional view of an axle assembly
including a differential in accordance with the principles of the present disclosure;
Figure 2 is a cross-sectional side view of a locking differential of the
present teachings illustrating a drive shaft, pinion gear and ring gear of the drive train in
15 phantom;
Figure 3 is a cross-sectional side view of a locking differential of the
present teachings illustrating the disposition of the cross pin relative to the clutch
members;
Figure 4 is an exploded perspective view of one end of the differential
20 mechanism and dampening communication spring of the present teachings;
Figure 5 is a side view of the differential mechanism and the dampening
communication spring of the present teachings; and
Figure 6 is a perspective view of another representative example of the
dampening communication spring of the present teachings.
25 DETAILED DESCRIPTION
Figure 1 illustrates an axle assembly 1 1 incorporating adifferential 10 in
accordance with the principles of the present disclosure. The axle assembly 1 1 is part of
a drive train 13 used to transfer torque from a prime mover I5 (e.g., an engine, a motor,
or like power source) to left and right wheels 17L, 17R. The differential 10 includes a
30 differentia1 housing 12 (i.e., a differential case) and adifferential mechanism 38 (i.e., a
differential torque transfer arrangement) positioned within the differential housing 12.
The differential housing 12 carries a gear 14 (e.g., a ring gear) that intermeshes with a
drive gear 16 driven by a driveshaft 1 8 of the drivetrain 13. The differential mechanism
38 is configured to transfer torque from the differential housing 12 to left and right half
axle half shafts 30L, 30R that respectively correspond to the left and right wheels 17L,
5 17R. The differential 10 is enclosed within an axle housing 21 that protects the
differential 10 and contains lubricant (e.g., oil) for lubricating moving parts within the
axle housing 21. The differential housing 12 is mounted to rotate relative to the axle
housing 21 about an axis of rotation 23. In one example, bearings can be provided
between the differential housing 12 and the axle housing 21 to allow the differential
10 housing 12 to freely rotate about the axis of rotation 23 relative to the axle housing 21.
The left and right axle half shafts 30L, 30R are co-axially aligned along the axis of
rotation 23.
In certain examples, the axle assembly 11 can be incorporated into a
vehicle such as an all-terrain vehicle, a light utility vehicle, or other type of vehicle.
15 The differential 10 of the axle assembly 1 1 is configured to prevent individual wheel
spin and to provide enhanced traction performance on a variety of surfaces such as mud,
wet pavement, loose dirt and ice. In use, torque for rotating the differential housing 12
about the axis of rotation 23 is provided by the drive gear 16 that intermeshes with the
ring gear 14 carried by the differential housing 12. The differential mechanism 38
20 includes left and right clutches (e.g., disc style clutches) configured to transfer torque
from the rotating differential housing 12 to the left and right axle half shafts 30L, 30R
thereby driving rotation of the left and right wheels 17L, 17R. When the vehicle is
driven straight, the left and right clutches are both actuated such that torque from the
differential housing 12 is transferred equally to the left and right axle shafts 30L, 30R.
25 When the vehicle turns right, the left clutch is de-actuated while the right clutch remains
actuated. In this state, the differential mechanism 38 continues to drive rotation of the
right axle shaft 30R while the left axle shaft 30L is allowed to free wheel at a higher rate
of rotation than the right axle shaft 30R. When the vehicle makes a left turn, the right
clutch is de-actuated while the left clutch remains actuated. In this state, the differential
30 mechanism 38 continues to drive rotation of the left axle shaft 30L while the right axle
shaft 30R is allowed to free wheel at a higher rotational speed than the left axle shaft
30L.
It will be appreciated that the differential housing 12 can also be referred
to as a differential carrier, a ring gear carrier, a carrier, a differential casing, or like
terms. Also, the axle housing 21 can be referred to as a carrier housing, a service
housing or like terms.
5 Referring to FIGS. 2 and 3, the differential housing 12 may becomposed
of a main body 20 and a cap 22 that is fixedly mounted to the main body 20 at a pair of
mating annular flange portions 24A and 24B via fasteners 26 or any other suitable
fastening mechanism. The ring gear I4 may also be mounted to the housing 12 at the
mating flanges 24A, 24B via the fastener 26. Those skilled in the art will appreciate in
10 light of the disclosure that follows that the housing 12 may be defined by any
conventional structure known in the related art and that the present teachings are not
limited to a housing defined by a main body and a cap portion. Similarly, the housing
12 may be driven by any conventional drive mechanism known in the related art and
that the present teachings are not limited to a housing that is driven via a ring gear,
15 pinion gear, and drive shaft.
The main body 20 defines a hub 28 that supports the left axle shaft 30L
(e.g., via a rotational bearing) to allow for rotation relative to the housing 12 about the
axis of rotation 23. Similarly, the cap 22 defines an opposed hub 34 that supports the
right axle half shaft 30R (e.g. via a rotational bearing) to allow for rotation relative to
20 the housing 12 about the axis of rotation 23. Together, the main body 20 and cap 22 of
the case 12 cooperate to define a cavity 36. The differential mechanism 38, is supported
in the cavity 36 defined by the housing 12.
The differential mechanism 38 is also illustrated in the exploded view of
Figure 4. The differential mechanism 38 includes left and right clutch members 40L, 40
25 R disposed in spaced axial relationship with respect to one another. The clutch
members 40L, 40R are operatively supported for rotation with the housing 12. Left and
right side gears 42L, 42R are each operatively adapted for rotation with a corresponding
one ofthe left and right axle half shafts 30L, 30R. To this end, the side gears 42L, 42R
each define a plurality of splines 46 on the inner circumference thereofthat are matingly
30 received in corresponding splines defined on their corresponding axle half shafts 30L,
30R. Left and right clutch mechanisms 48L, 48R are operatively disposed between the
clutch members 40L, 40R and their corresponding side gears 42L, 42R. When actuated,
the clutch mechanisms 48L, 48R are configured to transfer torque from the clutch
members 40L, 40R to their respective side gears 42L, 42R so as to resist or prevent
relative rotation about the axis of rotation 23 between the clutch members 40L, 40R and
their respective side gears 40L, 40R. The side gears 42L, 42R include a plurality of
splines 52 on the outer circumference thereof. The clutch mechanism 48L, 48R include
5 a plurality of friction disks 54 that are cooperatively splined to the outer circumference
of the side gears 42L, 42R and are rotatable therewith. Similarly, each of the clutch
members 40L, 40R includes a plurality of splines 56 formed on the inner circumference
thereof. A series of plates 58 have outer splines that engage the splined inner
circumference 56 of the left and right clutch members 40L, 40R. The plates 58 are
10 interleaved between the friction disks 54 supported on the side gears 42L, 42R. The
plates 58 and the friction discs 54 form clutch packs 59. The clutch members 40L, 40R
are axially moveable within the housing 12 to engage/actuate their respective clutch
mechanism 48L, 48R by axially compressing together the plates 58 and friction discs 54
(i.e., the clutch packs 59). When the clutch mechanisms 48L, 48R are actuated, torque
15 is transferred from the clutch members 40L, 40R, through the clutch packs 59 to the
side gears 42L, 42R and their corresponding axle half shafts 30L, 30R. When both
clutch mechanisms 48L, 48R are fully actuated, the housing 12, the clutch members
40L, 40R, the side gears 42L, 42R and the axle half shafts 30L, 30R all rotate in unison
with each other about the axis of rotation 23. One representative example of the
20 locking differential 10 of the type contemplated by the present teachings may also
employ a plurality of biasing members (not shown) that are disposed between the clutch
members 40L, 40R and received in pockets (not shown) formed in the opposed clutch
members 40L, 40R to urge the clutch members 40L, 40R away from one another to preload
the clutch packs 59.
2 5 Referring to Figure 3, the clutch members 40L, 40R present inwardly
directed faces 62 (i.e., inboard sides) that face toward a cross shaft or pin 66 mounted
between the clutch members 40L, 40R. The clutch members 40L, 40R also include
outwardly directed faces 63 (i.e., outbound sides) that face away from the pin 66. The
inwardly directed faces 62 of the clutch members 40L, 40R oppose each other and are
30 disposed in spaced axial relationship to one another. Each of the inwardly directed
faces 62 of the clutch members 40 includes a groove 64 disposed in facing relationship
with respect to the other. The cross pin 66 is received in the grooves 64 and is
operatively connected for rotation with the housing 12 about the axis 23. The cross pin
66 is generally cylindrical in shape and has an aperture 68 extending radially
therethrough at one end. Opposite ends ofthe cross pin 66 can fit within corresponding
radial openings defined by the housing 12 and the aperture 68 allows the cross pin 66 to
be pinned in place relative to the housing 12 to prevent the cross pin 66 from sliding
5 along its axis relative to the housing 12. The grooves 64 are defined at the inwardly
directed faces 62 of the clutch members 40L, 40R. Each groove 64 is defined by ramp
surfaces 65 that converge toward a neutral position 67. The neutral positions 67 form
the deepest portions of the grooves 64. The clutch members 40L, 40R can rotate a
limited amount relative to the cross pin 66 about the axis 23 between actuated positions
10 where the cross pin 66 engages (e.g., rides on) the ramp surfaces 65 and non-actuated
positions where the cross pin 66 is offset fiom the ramp surfaces 65 and aligns with the
neutral positions 67. Each groove 64 includes two groove portions 64% 64b positioned
on opposite sides of the axis 23. Each grove portion 64a, 64b includes a forward ramp
65F and a rearward ramp 65R separated fiom one another by the neutral position 67.
15 During normal forward driving conditions, the cross pin 66 engages the forward ramp
surfaces 65F to force the clutch members 40L, 40R axially outwardly thereby actuating
the clutch mechanisms 48L, 48R. During normal rearward driving conditions, the cross
pin 66 engages the rear ramp surfaces 65R to force the clutch members 40L, 40R
axially outwardly thereby actuating the clutch mechanisms 48L, 48R.
20 Referring to Figures 4 and 5, the clutch mechanisms 48L, 48R include
first springs 88 that are disposed on the outboard sides of the clutch members 40L, 40R
to contact an outer surface of the clutch members 40L, 40R to pre-load the clutch
members 40L, 40R. The springs 88 bias the clutch members 40L, 40R in an inboard
orientation against the cross pin 66. The first springs 88 can include wave springs each
25 having a predetermined spring force. First washers 90 are disposed on the outboard
sides ofthe first springs 88 for each ofthe clutch mechanisms 48,50. Each first washer
90 has an annular recess 92. The clutch mechanisms 48L, 48R each include second
springs 94 disposed in the annular recesses 92 of the first washers 90 to pre-load the
clutch mechanisms 48L, 48R. The second springs 94 can include wave springs each
30 having a predetermined spring force less than the predetermined spring force of each
first spring 88. A second washer 96 may be disposed against the inboard side of each
second spring 94. It should be appreciated that the springs 88, 94 are arranged in
parallel for applying the pre-load to the clutch members 40 to maintain contact with the
cross pin 66. In other examples, springs other than wave springs (e.g., coil springs, flat
leaf springs, etc.) can be used as the first and/or second springs.
The clutch members 40L, 40R are axially moveable within the housing
12 to axially compress the clutch packs 59 of their respective clutch mechanisms 48L,
5 48R so as to actuate the clutch mechanisms 48L, 48R. Clutch actuation occurs when
contact between the ramp surfaces 65 and the cross pin 66 forces the clutch members
40L, 40R axially outwardly to compress the clutch packs 59. The actuation forces are
large enough allow a substantial amount oftorque to be transferred through the clutch
packs 59, In certain examples, the actuation forces are sufficiently large for the clutch
10 packs to essentially lock the clutch members 40L, 40R relative to their respective side
gears 42L, 42R such that the side gears 42L, 42R and their respective clutch members
40L, 40R rotate in unison about the axis 23.
When the cross pin 66 is aligned with the neutral positions 67 of the
grooves 64 of one of the clutch members 40L, 40R, the corresponding clutch pack
15 59 is not axially compressed by the corresponding clutch member 40L, 40R and is
therefore not actuated. When the clutch pack 59 is not actuated by its corresponding
clutch member 40L, 40R, only pre-load is applied to the clutch pack 59. In this nonactuated
state, the clutch plates and the fiiction discs can rotate relative to one
another during a wheel overspeed condition. Thus, during a wheel overspeed
20 condition, the non-actuated clutch pack corresponding to the overspeeding wheel
permits the corresponding side gear 42L, 42R and its corresponding axle half shaft
30L, 30R to rotate relative to the corresponding clutch member 40L, 40R.
During normal straight driving conditions, the cross pin 66 engages
the ramp surfaces 65 causing actuation of the clutch mechanisms 48L, 48R such that
25 the clutch packs 59 prevent relative rotation between the clutch members 40L, 40R
and their corresponding side gears 42L, 42R. Thus, driving torque is transferred
from the differential housing 12 and cross pin 66 through the clutch members 40L,
40R, the clutch packs and the side gears 42L, 42R to the axle half shafts 30L, 30R
and the wheels 17L, 17R. Thus, with both clutch packs actuated, the differential
30 housing 12, cross pin 66, the clutch members 40L, 40R, the side gears 42L, 42R, the
axle half shafts 30L, 30R and the wheels 17L, 17R all rotate in unison about the axis
23. During an overspeed condition (e.g., during a turn), the clutch member 40L, 40R
corresponding to the overspeeding wheel rotates relative to the cross pin 66 such that
the cross pin 66 disengages from the ramp surfaces 65 and becomes aligned with the
neutral positions 67 thereby causing the corresponding clutch pack 59 to no longer
be actuated. With the clutch pack 59 no longer actuated, only pre-load pressure is
applied to the corresponding clutch pack 59. The pre-load pressure is sufficiently
5 low that the de-actuated clutch permits relative rotation between the clutch member
40L, 40R and its corresponding side gear 42L, 42R to accommodate the faster
rotation of the overspeeding wheel relative to its corresponding clutch member 40L,
40R, the cross pin 66 and the differential housing 12. An intermating stop
arrangement 100 defined between the inboard sides of the clutch members 40L, 40R
10 allows for only a limited range of relative rotational movement between the clutch
members 40L, 40R about the axis 23. The stop arrangement 100 ensures that the
clutch members 40L, 40R don't over-rotate their corresponding neutral positions 67
past the cross pin 66 during an overspeed condition. If the clutch members 40L, 40R
were to over-rotate during an overspeed condition, the cross pin 66 would
15 inadvertently actuate a de-actuated clutch by engaging the ramp 65L, 65R on the
opposite side of the neutral position 67. The stop arrangement 100 prevents this
fiom happening thereby allowing the overspeeding wheel to maintain an overspeed
condition during a turn without interference from the clutch mechanisms 42L, 42R.
As illustrated in Figure 5, the differential mechanism 38 is shown
20 assembled. In one embodiment, the first springs 88 pre-load the clutch members
40L, 40R only fiom the outside to maintain constant contact between the clutch
members 40L, 40R and the cross pin 66. Thus, the first springs 88 do not direct preload
through the clutch packs of their corresponding clutch mechanisms 48L, 48R.
Instead, the clutch pack preload is determined only by the second springs 94. By
25 offsetting a "spring contact" point of the springs 88 radially outwardly outward to
the clutch members 40L, 40R, the pre-load exerted by the springs 88 can be applied
only to the clutch members 40L, 40R, which maintains the contact between the
clutch members 40L, 40R and the cross pin 66 and allows use of higher "spring"
loads since the corresponding clutch mechanisms 48L, 48R receive no additional
30 load. It should be appreciated that care must be taken not to increase this contact
provided by springs 88 such that an excessive amount of resistance prevents a
limited range of relative rotational movement about the axis 23 between the clutch
members 40L, 40R and the cross pin 66 so as to prevent actuation of the clutch
mechanisms 48L, 48R. For example, the pre-load provided by the first springs 88
should not prevent the cross pin 66 from riding up the ramps 65 to actuate the clutch
mechanisms 42L, 42R during normal forward or reverse driving conditions.
The pre-load provided by the second springs 94 should be large enough
5 such that the clutch packs provide sufficient resistance to rotational movement of the
clutch members 40L, 40R about the axis 23 for the cross pin 66 to ride up on the ramps
65 and cause actuation of the clutch mechanisms 48L, 48R as differential housing 12
and the cross pin 66 carried therewith are rotated about the axis 23 during normal
driving conditions. Also, the pre-load provided by the second springs 94 should not be
10 so large so as to cause the wheels 17L, 17R to sliplskid relative to the ground/road
surface when encountering an overspeed wheel condition. In one example, the clutch
pre-load applied to each clutch pack allows the clutch packs to transfer a pre-load torque
value that is less than a representative wheel slip torque value corresponding to the
outside wheel during a turn. The representative wheel slip torque value (i.e., the torque
15 required to have the wheel slip relative to the ground) is dependent upon the gross
weight of the vehicle and a selected coefficient of friction between the ground and the
wheel that corresponds to a low traction condition.
As described above, a limited range of relative rotation about the axis 23
is permitted between the clutch members 40L, 40R themselves and between the clutch
20 members 40L, 40R and the cross pin 66. The range of relative rotation is limited by the
stop arrangement 100 and allows for each clutch member 40L, 40R to rotate relative to
the cross pin 66 and the opposite clutch member 40L, 40R when an overspeed condition
takes place. For example, when the left wheel 17L experiences an overspeed condition,
the clutch member 40L can rotate relative to the cross pin 66 and the clutch member
25 40R from a first rotational position where the cross pin 66 engages a corresponding
ramp surface 65 of the clutch member 40L to a second rotation position where the cross
pin 66 aligns with the neutral position 67 of the clutch member 40L. With the clutch
member 40L in the first rotational position, the clutch mechanism 42L is actuated and
with the clutch member 40L in the second rotational position the clutch mechanism 42L
30 is de-actuated. The range of relative rotation permitted by the stop arrangement 100 has
a rotational angle that corresponds to the rotational distance between the first and
second rotational positions ofthe clutch member 40L relative to the cross pin 66 and the
clutch member 40R. Similarly, when the right wheel 17R experiences an overspeed
condition, the clutch member 40R can rotate relative to the cross pin 66 and the clutch
member 40L from a first rotational position where the cross pin 66 engages a
corresponding ramp surface 65 of the clutch member 40R to a second rotation position
where the cross pin 66 aligns with the neutral position 67 of the clutch member 40R.
5 With the clutch member 40R in the first rotational position, the clutch mechanism 42R
is actuated and with the clutch member 40R in the second rotational position the clutch
mechanism 42R is de-actuated. The range of relative rotation permitted by the stop
arrangement 100 has a rotational angle that corresponds to the rotational distance
between the first and second rotational positions of the clutch member 40R relative to
10 the cross pin 66 and the clutch member 40L.
The differential can also include a structure that provides a
limitedlcontrolled amount of frictional resistance that resists movement of the clutch
members 40L, 40R between the first and second rotational positions. The frictional
resistance is small enough to be overcome in an overspeed condition. Thus, the
15 frictional resistance is not large enough to prevent the clutch members from moving
between the first and second rotational positions. However, the frictional resistance is
large enough to prevent erratic motion within the mechanical travel limits defined by
the stop arrangement 100 so as to provide for smoother operation and reduced noise. In
certain examples, the structure for providing fiictional resistance may be rotationally
20 fixed relative to the cross pin 66 and may engage both of the clutch members 40L, 40R
to generate a limited friction force that must be overcome for either of the clutch
members 40L, 40R to rotate relative to the cross pin 66. In certain examples, the
structure for providing frictional resistance can include a spring that applies a biasing
force to the clutch members 40L, 40R. In certain examples, the structure for generating
25 fiictional resistance is a sleeve or circumferential clamp that is anchored against rotation
relative to the cross pin 66 and that clamps about the outer circumferences ofthe clutch
members 40L, 40R so as to resist rotational movement ofthe clutch members 40L, 40R
about the axis 23 relative to the cross pin 66. In one example, the sleeve/clamp can
include structure having elastic characteristics so as to apply a spring biased load to the
30 circumferences of the clutch members 40L, 40R. In certain examples, the sleeve/clamp
can be mounted about the circumferences of the clutch members 40L, 40R and can
traversehridge the interface between the inboard sides ofthe clutch members 40L, 40R.
In one example, the structure for providing frictional resistance may
include a dampening communication spring 70 disposed over the outer circumference of
the clutch members 40L, 40R (Figures 1 and 4) and cooperating with the cross pin 66.
As illustrated in Figure 4, the dampening communication spring 70 is generally circular
5 (e.g., cylindrical) in shape. The dampening communication spring 70 includes a first
arm portion 78 extending circumferentially and having a first slot 80 extending
circumferentially inward from one end thereof. The dampening communication spring
70 includes a second arm portion 82 opposing the first arm portion 78. The second arm
portion 82 extends circumferentially and has a first slot 84 extending circurnferentially
10 inward from one end thereof. The dampening communication spring 70 has a central
aperture 86 extending radially therethrough to receive one end of the cross pin 66. The
dampening communication spring 70 is made of a spring material such as a metal
material.
As illustrated in Figure 5, the dampening communication spring 70 is
15 assembled over the clutch members 40L, 40R. One end of the cross pin 66 is disposed
in and extended through the central aperture 86 in the dampening communication spring
70 and extends through the clutch members 40L, 40R. The dampening communication
spring 70 is grounded to the cross pin 66 and outside of each of the clutch members
40L, 40R such that there are multiple, in this case three, points of contact of the spring
20 70 to a remainder of the differential mechanism 38. By applying a spring coupling
between the clutch members 40 ofthe locking differential 10, control of the interaction
of the clutch members 40L, 40R can be achieved. The dampening communication
spring 70 prevents erratic motion within the mechanical travel limits. This provides for
smoother operation and reduced noise. The dampening communication spring 70 also
25 provides feedback to the differential clutch members 40 from the differential carrier.
This provides ultimate control of the dampening back to the driveline.
Referring to Figure 6, another representative example, according to the
present teachings, ofthe dampening communication spring 70 is shown. Like parts of
the dampening communication spring 70 have like reference numerals increased by one
30 hundred (100). In this representative example, the dampening communication spring
170 is generally circular in shape. The dampening communication spring 170 includes
a first arm portion 178 extending circumferentially and having a first slot 180 extending
circumferentially inward from one end thereof. The first arm portion 178 also has a pair
of second slots 18 1 extending circumferentially inward from the other end thereof and
spaced axially relative to each other. The dampening communication spring 170
includes a second arm portion 182 opposing the first arm portion 178. The second arm
portion 182 extends circumferentially and has a first slot 184 extending
5 circumferentially inward fiom one end thereof. The second arm portion 182 also has a
pair of second slots 185 extending circumferentially inward from the other end thereof
and spaced axially relative to each other. The dampening communication spring 170
has a bridge portion 187 extending circurnferentially between the first arm portion 178
and second arm portion 182. The bridge portion 187 has a central aperture 186
10 extending radially therethrough to receive one end of the cross pin 66. The bridge
portion 187 has an axial width less than an axial width of the first arm portion 178 and
second arm portion 182. The dampening communication spring 170 is made of a spring
material such as a metal material. The assembly and operation of the dampening
communication spring 170 is similar to the dampening communication spring 70.
15 The present teachings have been described in great detail in the
foregoing specification, and it is believed that various alterations and modifications of
the many aspects ofthe present teachings will become apparent to those ordinary skilled
in the art fiom a reading and understanding of the specification. It is intended that all
such alterations and modifications are included in the present teachings, insofar as they
20 come within the scope of the appended claims.
WO 201.11035868
We claim:
1. A differential for a vehicle comprising:
a rotatable housing and a differential mechanism supported in said housing, said
housing being rotatable about an axis of rotation, said differential mechanism including
a pair of clutch members disposed along the axis of rotation;
a pair of side gears operatively adapted for rotation with a corresponding pair of
axle half shafts, and a pair of clutch mechanisms operable for transferring torque
between the clutch members their corresponding side gears when actuated;
said clutch members being axially moveable along the axis or rotation within
said housing to actuate a respective clutch mechanism;
each of said clutch members presenting an inwardly directed face, each said face
including a groove disposed in facing relationship with respect to the other, and a cross
pin received in said groove and operatively connected for rotation with said housing
about the axis or rotation; and
a dampening communication spring disposed over an outer circumference of
said clutch members and cooperating with said cross pin to control interaction of said
clutch members.
2. A differential as set forth in claim 1 wherein said dampening communication
spring has a central aperture extending radially therethrough to receive one end of said
cross pin.
3. A differential as set forth in claim 2 wherein said dampening communication
spring includes a first arm portion extending circumferentially and having a first slot
extending circumferentially inward from one end thereof.
4. A differential as set forth in claim 3 wherein said dampening communication
spring includes a second arm portion opposing said first arm portion.
5. A differential as set forth in claim 4 wherein said second arm portion extends
circumferentially and has a first slot extending circumferentially inward from one end
thereof.
6. A differential as set forth in claim 5 wherein said first arm portion has a pair of
second slots extending circumferentially inward from the other end thereof and spaced
axially relative to each other.
7. A differential as set forth in claim 6 wherein said second arm portion has a pair
of second slots extending circumferentially inward from the other end thereof and
spaced axially relative to each other.
8. A differential as set forth in claim 7 wherein said dampening communication
spring has a bridge portion extending circumferentially between said first arm portion
and said second arm portion.
9. A differential as set forth in claim 8 wherein said bridge portion has said central
aperture extending radially therethrough to receive one end of said cross pin.

10. A differential as set forth in claim 9 wherein said bridge portion has an axial
width less than an axial width of the first arm portion and second arm portion.
11. A differential as set forth in claim 1 wherein said dampening communication
spring is made of a spring material.
12. The differential as set forth in claim 1, wherein said dampening communication
spring includes a spring sleeve that clamps about the circumferences of the clutch
members to generate fiiction that resists relative rotation between the clutch members.

13. The differential as set forth in claim 12, wherein the spring sleeve is anchored
relative to the cross pin to prevent relative rotation between the cross pin and the spring
sleeve about the axis of rotation, wherein the spring sleeve includes a first portion that
clamps on of the clutch members and a second portion that clamps on the other of the
clutch members.
14. The differential as set forth in claim 1, wherein the clutch members are rotatable
through a limited range of rotation relative to one another about the axis of rotation,
wherein the clutch members include a stop arrangement that defines the limited range of
relative rotation permitted between the clutch members, and wherein the dampening
communication spring provides friction that resists rotation between the clutch members
through the limited range of rotation.

15. The differential of claim 14, wherein the grooves ofthe clutch members include
ramps that converge toward neutral positions, wherein the limited range of rotation
permitted between the clutch members corresponds to a rotational distance between a
clutch actuated state where the cross pin contacts a ramp surface and a clutch de-
actuated state where the cross pin aligns with the neutral position.
16. A drive train including the differential of claim 1, the drive train including a
drive shaft coupled to a drive gear that engages a ring gear carried by the housing,
wherein the drive shaft and the drive gear provide torque for rotating the housing about
the axis of rotation.
17. An axle assembly including the differential of claim 1, the axle assembly
including the axle half shafts, and the axle half shafts being co-axially aligned along the
axis of rotation.

18. A differential for a vehicle comprising:
a rotatable housing and a differential mechanism supported in said housing, said
housing being rotatable about an axis of rotation, said differential mechanism including
a pair of clutch members disposed along the axis of rotation;
a pair of side gears operatively adapted for rotation with a corresponding pair of
axle half shafts, and a pair of clutch mechanisms operable for transferring torque
between the clutch members their corresponding side gears when actuated;
said clutch members being axially moveable along the axis or rotation within
said housing to actuate a respective clutch mechanism;
each of said clutch members presenting an inwardly directed face, each said face
including a groove disposed in facing relationship with respect to the other, and a cross
pin received in said groove and operatively connected for rotation with said housing
about the axis or rotation; and
a friction enhancing structure that applies pressure to circumferential surfaces of
the clutch members to resist relative rotation between the clutch members about the axis
of rotation.
19. The differential of claim 18, wherein the friction enhancing structure is anchored
to the cross pin and traverses and interface between the clutch members.
20. The differential of claim 18, wherein the friction enhancing structure includes a
spring sleeve that extends about the circumferential surfaces of the clutch members.

21. The differential as set forth in claim 18, wherein the clutch members are
rotatable through a limited range of rotation relative to one another about the axis of
rotation, wherein the clutch members include a stop arrangement that defines the limited
range of relative rotation permitted between the clutch members, wherein friction
enhancing structure provides friction that resists rotation between the clutch members
through the limited range of rotation, wherein the grooves of the clutch members
include ramps that converge toward neutral positions, wherein the limited range of
rotation permitted between the clutch members corresponds to a rotational distance
between a clutch actuated state where the cross pin contacts a ramp surface and a clutch
de-actuated state where the cross pin aligns with the neutral position.
22. A drive train including the differential of claim 18, the drive train including a
drive shaft coupled to a drive gear that engages a ring gear carried by the housing,
wherein the drive shafi and the drive gear provide torque for rotating the housing about
the axis of rotation.
23. An axle assembly including the differential of claim 18, the axle assembly
including the axle half shafts, and the axle half shafts being co-axially aligned along the
axis of rotation.

24. A differential for a vehicle comprising:
a rotatable housing and a differential mechanism supported in said housing, said
housing being rotatable about an axis of rotation, said differential mechanism including
a pair of clutch members disposed along the axis of rotation;
a pair of side gears operatively adapted for rotation with a corresponding pair of
axle half shafts, and a pair of clutch mechanisms operable for transferring torque
between the clutch members their corresponding side gears when actuated;
said clutch members being axially moveable along the axis or rotation within
said housing to actuate a respective clutch mechanism;
each of said clutch members presenting an inwardly directed face, each said face
including a groove disposed in facing relationship with respect to the other, and a cross
pin received in said groove and operatively connected for rotation with said housing
about the axis or rotation;
a friction sleeve that mounts about circumferences of the clutch members and
that engages the circumferences of the clutch members to resist relative rotation
between the clutch members about the axis of rotation;
wherein the clutch members are rotatable through a limited range of rotation
relative to one another about the axis of rotation, wherein the clutch members include a
stop arrangement that defines the limited range of relative rotation permitted between
the clutch members, wherein the friction sleeve provides friction that resists rotation
between the clutch members through the limited range of rotation, wherein the grooves
of the clutch members include ramps that converge toward neutral positions, wherein
the limited range of rotation permitted between the clutch members corresponds to a
rotational distance between a clutch actuated state where the cross pin contacts a ramp
surface and a clutch de-actuated state where the cross pin aligns with the neutral
position.
25. The differential of claim 24, wherein the friction sleeve is anchored to the cross
pin and traverses and interface between the clutch members.
26. The differential of claim 24, wherein the friction sleeve defines an opening that
receives the cross pin and clamping portions on opposite axial sides ofthe cross pin that
clamp on the clutch members.
27. A drive train including the differential of claim 24, the drive train including a
drive shaft coupled to a drive gear that engages a ring gear carried by the housing,
wherein the drive shaft and the drive gear provide torque for rotating the housing about
the axis of rotation.
28. An axle assembly including the differential of claim 24, the axle assembly
including the axle half shafts, and the axle half shafts being co-axially aligned along
the axis of rotation.