U.S. patent application number 15/563653 was filed with the patent office on 2018-03-08 for controllable coupling assembly having forward and reverse backlash.
This patent application is currently assigned to MEANS INDUSTRIES, INC.. The applicant listed for this patent is MEANS INDUSTRIES, INC.. Invention is credited to Douglas E. BRUBAKER, Brice A. PAWLEY, Jeffrey J. PROUT.
Application Number | 20180066716 15/563653 |
Document ID | / |
Family ID | 57006455 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180066716 |
Kind Code |
A1 |
BRUBAKER; Douglas E. ; et
al. |
March 8, 2018 |
CONTROLLABLE COUPLING ASSEMBLY HAVING FORWARD AND REVERSE
BACKLASH
Abstract
A controllable or selectable coupling assembly includes a
plurality of forward locking elements, at least one reverse locking
element and first and second coupling members supported for
relative rotation about a common rotational axis. The coupling
members include a first, second and third coupling faces. The first
coupling face has a set of forward pockets angularly spaced about
the axis. The second coupling face has a set of reverse locking
formations adapted for abutting engagement with the at least one
reverse locking element. The third coupling face opposes the first
coupling face and has a set of forward locking formations. Either
forward backlash is a non-zero integer multiple of reverse backlash
or the reverse backlash is a non-zero integer multiple of the
forward backlash to prevent the coupling assembly from
inadvertently binding in both directions (i.e. a "lock-lock"
condition) about the axis.
Inventors: |
BRUBAKER; Douglas E.;
(Midland, MI) ; PAWLEY; Brice A.; (Midland,
MI) ; PROUT; Jeffrey J.; (Freeland, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEANS INDUSTRIES, INC. |
Saginaw |
MI |
US |
|
|
Assignee: |
MEANS INDUSTRIES, INC.
Saginaw
US
|
Family ID: |
57006455 |
Appl. No.: |
15/563653 |
Filed: |
January 19, 2016 |
PCT Filed: |
January 19, 2016 |
PCT NO: |
PCT/US16/13836 |
371 Date: |
October 2, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14675856 |
Apr 1, 2015 |
9482297 |
|
|
15563653 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16D 41/125 20130101;
F16D 41/14 20130101; F16D 41/16 20130101 |
International
Class: |
F16D 41/16 20060101
F16D041/16; F16D 41/12 20060101 F16D041/12 |
Claims
1. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one forward locking
element having a load-bearing surface; at least one reverse locking
element; and first and second coupling members supported for
relative rotation about a common rotational axis, the coupling
members including: a first coupling face having a forward pocket to
receive each forward locking element and defining a forward
load-bearing surface adapted for abutting engagement with the
load-bearing surface of its respective forward locking element; a
second coupling face having a set of reverse locking formations
adapted for abutting engagement with the at least one reverse
locking element to prevent the relative rotation in a reverse
direction about the axis; and a third coupling face that opposes
the first coupling face, the third coupling face having a set of
forward locking formations, each of the set of forward locking
formations being adapted for abutting engagement with at least one
forward locking element to prevent the relative rotation in a
forward direction about the axis, wherein either the forward
backlash is a non-zero integer multiple of the reverse backlash or
the reverse backlash is a non-zero integer multiple of the forward
backlash to prevent the coupling assembly from inadvertently
binding in both directions about the axis.
2. The assembly as claimed in claim 1, further comprising a fourth
coupling face that opposes the second coupling face, the fourth
coupling face having at least one reverse pocket, each reverse
pocket receiving a reverse locking element and defining a reverse
load-bearing surface adapted for abutting engagement with a
load-bearing surface of its respective reverse locking element.
3. The assembly as claimed in claim 1, wherein the first coupling
face has a plurality of forward pockets and wherein the forward
pockets are grouped into at least one set and wherein the forward
pockets in each set are uniformly angularly spaced.
4. The assembly as claimed in claim 3, wherein the forward pockets
are grouped into two or more sets.
5. The assembly as claimed in claim 1, wherein the first coupling
member has the first and second coupling faces and the second
coupling member has the third coupling face.
6. The assembly as claimed in claim 1, wherein the first coupling
face is oriented to face axially in a first direction along the
axis, and wherein the second coupling face is oriented to face
axially in a second direction opposite the first direction along
the axis.
7. The assembly as claimed in claim 1, wherein the forward and
reverse locking elements are locking struts.
8. The assembly as claimed in claim 1, wherein the forward and
reverse locking formations are notches.
9. The assembly as claimed in claim 1, wherein the first coupling
member is a splined ring.
10. The assembly as claimed in claim 1, wherein the first and third
coupling faces are annular coupling faces that oppose each
other.
11. The assembly as claimed in claim 1, further comprising a
plurality of reverse locking elements and a third coupling member
having a fourth coupling face that opposes the second coupling
face, the fourth coupling face having a set of reverse pockets
angularly spaced about the axis, each of the reverse pockets
receiving one of the reverse locking elements and defining a
reverse load-bearing surface adapted for abutting engagement with a
load-bearing surface of its respective reverse locking element.
12. The assembly as claimed in claim 11, wherein the reverse
pockets are grouped into at least one set and wherein the reverse
pockets in each set are uniformly angularly spaced.
13. The assembly as claimed in claim 12, wherein the reverse
pockets are grouped into two or more sets.
14. The assembly as claimed in claim 11, further comprising: a
control member mounted for controlled, shifting movement between
the second and fourth coupling faces relative to the set of reverse
pockets and operable for controlling position of the reverse
locking elements, the control member allowing at least one of the
reverse locking elements to engage at least one of the reverse
locking formations in a first position of the control member and
wherein the control member maintains the reverse locking elements
in their pockets in a second position of the control member.
15. The assembly as claimed in claim 14, wherein the control member
comprises a slide plate controllably rotatable about the rotational
axis between the first and second positions.
16. The assembly as claimed in claim 14, further comprising a
control element coupled to the control member to controllably shift
the control member.
17. The assembly as claimed in claim 11, wherein the assembly
further comprises: a generally round snap ring that is received by
an annular groove in the third coupling member to retain the
members together and prevent axial movement of the members relative
to one another.
18. A controllable clutch assembly having forward and reverse
backlash, the assembly comprising: at least one forward locking
element having a load-bearing surface; at least one reverse locking
element; and first and second clutch members supported for relative
rotation about a common rotational axis, the clutch members
including: a first coupling face having a forward pocket to receive
each forward locking element and defining a forward load-bearing
surface adapted for abutting engagement with the load-bearing
surface of its respective forward locking element; a second
coupling face having a set of reverse locking formations adapted
for abutting engagement with the at least one reverse locking
element to prevent the relative rotation in a reverse direction
about the axis; and a third coupling face that opposes the first
coupling face, the third coupling face having a set of forward
locking formations, each of the set of forward locking formations
being adapted for abutting engagement with at least one forward
locking element to prevent the relative rotation in a forward
direction about the axis, wherein either the forward backlash is a
non-zero integer multiple of the reverse backlash or the reverse
backlash is a non-zero integer multiple of the forward backlash to
prevent the coupling assembly from inadvertently binding in both
directions about the axis.
19. The assembly as claimed in claim 18, wherein the first coupling
face has a plurality of forward pockets and wherein forward pockets
are grouped into two or more sets.
20. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one forward locking
element having a load-bearing surface; a plurality of reverse
locking elements, each of the reverse locking elements having a
load-bearing surface; and first, second and third coupling members
supported for relative rotation about a common rotational axis, the
coupling members including: a first coupling face having at least
one forward pocket receiving the at least one forward locking
element and defining a forward load-bearing surface adapted for
abutting engagement with the load-bearing surface of its respective
forward locking element; a second coupling face having a set of
reverse locking formations, each of the set of reverse locking
formations being adapted for abutting engagement with one of the
reverse locking elements to prevent the relative rotation in a
reverse direction about the axis; a third coupling face that
opposes the first coupling surface, the third coupling face having
a set of forward locking formations, each of the set of forward
locking formations being adapted for abutting engagement with the
at least one forward locking element to prevent the relative
rotation in a forward direction about the axis; and a fourth
coupling face that opposes the second coupling face, the fourth
coupling face having a set of reverse pockets angularly spaced
about the axis, each of the reverse pockets receiving one of the
reverse locking elements and defining a reverse load-bearing
surface adapted for abutting engagement with a load-bearing surface
of its respective reverse locking element wherein either the
forward backlash is a non-zero integer multiple of the reverse
backlash or the reverse backlash is a non-zero integer multiple of
the forward backlash to prevent the coupling assembly from
inadvertently binding in both directions about the axis.
21. The assembly as claimed in claim 20, wherein the reverse
pockets are grouped into at least one set and wherein the reverse
pockets in each set are uniformly angularly spaced.
22. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one forward and at
least one reverse locking element; and first and second coupling
members supported for relative rotation about a common rotational
axis, the coupling members including: a first coupling rotatable
inner ring containing the at least one forward locking member
having a biasing member allowing it to engage into an outer member
that has locking formations and the at least one reverse locking
member contained in the outer member that can be controlled to
engage or disengage with locking formations contained on the inner
ring, wherein either the forward backlash is a non-zero integer
multiple of the reverse backlash or the reverse backlash is a
non-zero integer multiple of the forward backlash to prevent the
coupling assembly from inadvertently binding in both directions
about the axis.
23. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one controllable
forward and at least one reverse locking element; and first and
second coupling members supported for relative rotation about a
common rotational axis, the coupling members including: a first
coupling rotatable inner ring containing the at least one
controllable forward locking member allowing it to engage into an
outer member that has locking formations and the at least one
reverse locking member contained in the outer member that can be
controlled to engage or disengage with locking formations contained
on the inner ring, wherein either the forward backlash is a
non-zero integer multiple of the reverse backlash or the reverse
backlash is a non-zero integer multiple of the forward backlash to
prevent the coupling assembly from inadvertently binding in both
directions about the axis.
24. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one forward and at
least one reverse locking element; and first and second coupling
members supported for relative rotation about a common rotational
axis, the coupling members including: a first coupling rotatable
inner ring containing opposing locking formations radially
distributed on the outer circumference of the inner ring and an
outer member containing at least one each, forward and reverse
locking elements radially distributed that can be controlled to
engage and disengage with locking formations contained on the inner
ring, wherein either the forward backlash is a non-zero integer
multiple of the reverse backlash or the reverse backlash is a
non-zero integer multiple of the forward backlash to prevent the
coupling assembly from inadvertently binding in both directions
about the axis.
25. A controllable coupling assembly having forward and reverse
backlash, the assembly comprising: at least one forward and at
least one reverse locking element; and first and second coupling
members supported for relative rotation about a common rotational
axis, the coupling members including; a first coupling rotatable
inner ring containing opposing locking formations radially
distributed on the outer circumference of the inner ring and an
outer member containing at least one each, forward and reverse
locking elements radially distributed, one of which can be
controlled to engage or disengage with locking formations contained
on the inner ring and the other locking element having a biasing
member allowing it to engage into the outer member in the forward
direction, wherein either the forward backlash is a non-zero
integer multiple of the reverse backlash or the reverse backlash is
a non-zero integer multiple of the forward backlash to prevent the
coupling assembly from inadvertently binding in both directions
about the axis
Description
TECHNICAL FIELD
[0001] This invention generally relates to controllable coupling or
clutch assemblies and, in particular, to such assemblies which have
forward and reverse backlash.
OVERVIEW
[0002] Coupling assemblies such as clutches are used in a wide
variety of applications to selectively couple power from a first
rotatable driving member, such as a driving disk or plate, to a
second, independently rotatable driven member, such as a driven
disk or plate. In one known variety of clutches, commonly referred
to as "one-way" or "overrunning" clutches, the clutch engages to
mechanically couple the driving member to the driven member only
when the driving member rotates in a first direction relative to
the driven member. Further, the clutch otherwise permits the
driving member to freely rotate in the second direction relative to
the driven member. Such "freewheeling" of the driving member in the
second direction relative to the driven member is also known as the
"overrunning" condition.
[0003] One type of one-way clutch includes coaxial driving and
driven plates having generally planar clutch faces in closely
spaced, juxtaposed relationship. A plurality of recesses or pockets
is formed in the face of the driving plate at angularly spaced
locations about the axis, and a strut or pawl is disposed in each
of the pockets. Multiple recesses or notches are formed in the face
of the driven plate and are engageable with one or more of the
struts when the driving plate is rotating in a first direction.
When the driving plate rotates in a second direction opposite the
first direction, the struts disengage the notches, thereby allowing
freewheeling motion of the driving plate with respect to the driven
plate.
[0004] When the driving plate reverses direction from the second
direction to the first direction, the driving plate typically
rotates relative to the driven plate until the clutch engages. As
the amount of relative rotation increases, the potential for an
engagement noise also increases.
[0005] Controllable or selectable one-way clutches (i.e., OWCs) are
a departure from traditional one-way clutch designs. Selectable
OWCs add a second set of locking members in combination with a
slide plate. The additional set of locking members plus the slide
plate adds multiple functions to the OWC. Depending on the needs of
the design, controllable OWCs are capable of producing a mechanical
connection between rotating or stationary shafts in one or both
directions. Also, depending on the design, OWCs are capable of
overrunning in one or both directions. A controllable OWC contains
an extremely controlled selection or control mechanism. Movement of
this selection mechanism can be between two or more positions which
correspond to different operating modes.
[0006] U.S. Pat. No. 5,927,455 discloses a bi-directional
overrunning pawl-type clutch, U.S. Pat. No. 6,244,965 discloses a
planar overrunning coupling, and U.S. Pat. No. 6,290,044 discloses
a selectable one-way clutch assembly for use in an automatic
transmission. U.S. Pat. Nos. 7,258,214 and 7,344,010 disclose
overrunning coupling assemblies, and U.S. Pat. No. 7,484,605
discloses an overrunning radial coupling assembly or clutch.
[0007] A properly designed controllable OWC can have near-zero
parasitic losses in the "off" state. It can also be activated by
electro-mechanics and does not have either the complexity or
parasitic losses of a hydraulic pump and valves.
[0008] In a powershift transmission, tip-in clunk is one of most
difficult challenges due to absence of a torque converter. When the
driver tips-in, i.e., depresses the accelerator pedal following a
coast condition, gear shift harshness and noise, called clunk, are
heard and felt in the passenger compartment due to the mechanical
linkage, without a fluid coupling, between the engine and
powershift transmission input. Tip-in clunk is especially acute in
a parking-lot maneuver, in which a vehicle coasting at low speed is
then accelerated in order to maneuver into a parking space.
[0009] In order to achieve good shift quality and to eliminate
tip-in clunk, a powershift transmission should employ a control
strategy that is different from that of a conventional automatic
transmission. The control system should address the unique
operating characteristics of a powershift transmission and include
remedial steps to avoid the objectionable harshness yet not
interfere with driver expectations and performance requirements of
the powershift transmission. There is a need to eliminate shift
harshness and noise associated with tip-in clunk in a powershift
transmission.
[0010] For purposes of this disclosure, the term "coupling" should
be interpreted to include clutches or brakes wherein one of the
plates is drivably connected to a torque delivery element of a
transmission and the other plate is drivably connected to another
torque delivery element or is anchored and held stationary with
respect to a transmission housing. The terms "coupling", "clutch"
and "brake" may be used interchangeably.
[0011] A pocket plate may be provided with angularly disposed
recesses or pockets about the axis of the one-way clutch. The
pockets are formed in the planar surface of the pocket plate. Each
pocket receives a torque transmitting strut, one end of which
engages an anchor point in a pocket of the pocket plate. An
opposite edge of the strut, which may hereafter be referred to as
an active edge, is movable from a position within the pocket to a
position in which the active edge extends outwardly from the planar
surface of the pocket plate. The struts may be biased away from the
pocket plate by individual springs.
[0012] A notch plate may be formed with a plurality of recesses or
notches located approximately on the radius of the pockets of the
pocket plate. The notches are formed in the planar surface of the
notch plate.
[0013] Another example of an overrunning planar clutch is disclosed
in U.S. Pat. No. 5,597,057.
[0014] Some U.S. patents related to the present invention include:
U.S. Pat. Nos. 4,056,747; 5,052,534; 5,070,978; 5,449,057;
5,486,758; 5,678,668; 5,806,643; 5,871,071; 5,918,715; 5,964,331;
5,979,627; 6,065,576; 6,116,394; 6,125,980; 6,129,190; 6,186,299;
6,193,038; 6,386,349; 6,481,551; 6,505,721; 6,571,926; 6,814,201;
7,153,228; 7,275,628; 8,051,959; 8,196,724; and 8,286,772.
[0015] Yet still other related U.S. patents include: U.S. Pat. Nos.
4,200,002; 5,954,174; and 7,025,188.
[0016] U.S. Pat. No. 6,854,577 discloses a sound-dampened, one-way
clutch including a plastic/steel pair of struts to dampen
engagement clunk. The plastic strut is slightly longer than the
steel strut. This pattern can be doubled to dual engaging. This
approach has had some success. However, the dampening function
stopped when the plastic parts became exposed to hot oil over a
period of time.
[0017] Metal injection molding (MIM) is a metalworking process
where finely-powdered metal is mixed with a measured amount of
binder material to comprise a `feedstock` capable of being handled
by plastic processing equipment through a process known as
injection mold forming. The molding process allows complex parts to
be shaped in a single operation and in high volume. End products
are commonly component items used in various industries and
applications. The nature of MIM feedstock flow is defined by a
science called rheology. Current equipment capability requires
processing to stay limited to products that can be molded using
typical volumes of 100 grams or less per "shot" into the mold.
Rheology does allow this "shot" to be distributed into multiple
cavities, thus becoming cost-effective for small, intricate,
high-volume products which would otherwise be quite expensive to
produce by alternate or classic methods. The variety of metals
capable of implementation within MIM feedstock are referred to as
powder metallurgy, and these contain the same alloying constituents
found in industry standards for common and exotic metal
applications. Subsequent conditioning operations are performed on
the molded shape, where the binder material is removed and the
metal particles are coalesced into the desired state for the metal
alloy.
[0018] Other U.S. patent documents related to at least one aspect
of the present invention includes U.S. Pat. Nos. 8,813,929;
8,491,440; 8,491,439; 8,286,772; 8,272,488; 8,187,141; 8,079,453;
8,007,396; 7,942,781; 7,690,492; 7,661,518; 7,455,157; 7,455,156;
7,451,862; 7,448,481, 7,383,930; 7,223,198; 7,100,756; and
6,290,044; and U.S. published application Nos. 2015/0000442;
2014/0305761; 2013/0277164; 2013/0062151; 2012/0152683;
2012/0149518; 2012/0152687; 2012/0145505; 2011/0233026;
2010/0105515; 2010/0230226; 2009/0233755; 2009/0062058;
2009/0211863; 2008/0110715; 2008/0188338; 2008/0185253;
2006/0124425; 2006/0249345; 2006/0185957; 2006/0021838;
2004/0216975; and 2005/0279602.
[0019] Some other U.S. patent documents related to at least one
aspect of the present invention includes U.S. Pat. Nos. 8,720,659;
8,418,825; 5,996,758; 4,050,560; 8,061,496; 8,196,724; and U.S.
published application Nos. 2014/0190785; 2014/0102844;
2014/0284167; 2012/0021862; 2012/0228076; 2004/0159517; and
2010/0127693.
[0020] A problem has arisen with some controllable one-way clutches
(i.e. mechanical diodes (MD's)) which are meant to lock in one
direction and lock or free wheel in the opposite direction,
depending upon the position of a selector. In certain positions or
locations, the clutch may not come out of a "lock-lock" condition
(i.e. may inadvertently bind in both directions about the
axis).
SUMMARY OF EXAMPLE EMBODIMENTS
[0021] An object of at least one embodiment of the present
invention is to provide a controllable coupling assembly having
forward and reverse backlash and which is prevented from
inadvertently binding.
[0022] In carrying out the above object and other objects of at
least one embodiment of the present invention, a controllable
coupling assembly having forward and reverse backlash is provided.
The assembly includes a plurality of forward locking elements. Each
of the forward locking elements has a load-bearing surface. The
assembly also includes at least one reverse locking element and
first and second coupling members supported for relative rotation
about a common rotational axis. The coupling members include a
first coupling face having a set of forward pockets angularly
spaced about the axis. Each of the forward pockets receives one of
the forward locking elements and defines a forward load-bearing
surface adapted for abutting engagement with the load-bearing
surface of its respective forward locking element. The members also
include a second coupling face which has a set of reverse locking
formations adapted for abutting engagement with the at least one
reverse locking element to prevent the relative rotation in a
reverse direction about the axis and a third coupling face that
opposes the first coupling face. The third coupling face has a set
of forward locking formations. Each of the set of forward locking
formations is adapted for abutting engagement with one of the
forward locking elements to prevent the relative rotation in a
forward direction about the axis. The number of forward locking
elements is different than the number of reverse locking elements.
The number of forward locking formations is different than the
number of reverse locking formations. Either the forward backlash
is a non-zero integer multiple of the reverse backlash or the
reverse backlash is a non-zero integer multiple of the forward
backlash to prevent the coupling assembly from inadvertently
binding in both directions about the axis.
[0023] The assembly may further include a fourth coupling face that
opposes the second coupling face. The fourth coupling face may have
at least one reverse pocket. Each reverse pocket may receive a
reverse locking element and may define a reverse load-bearing
surface adapted for abutting engagement with a load-bearing surface
of its respective reverse locking element.
[0024] The forward pockets may be grouped into at least one set
wherein the forward pockets in each set are uniformly angularly
spaced.
[0025] The forward pockets may be grouped into two or more
sets.
[0026] The first coupling member may have the first and second
coupling faces and the second coupling member may have the third
coupling face.
[0027] The first coupling face may be oriented to face axially in a
first direction along the axis, wherein the second coupling face
may be oriented to face axially in a second direction opposite the
first direction along the axis.
[0028] The forward and reverse locking elements may be locking
struts.
[0029] The forward and reverse locking formation may be
notches.
[0030] The first coupling member may be a splined ring.
[0031] The first and third coupling faces may be annular coupling
faces that oppose each other.
[0032] The assembly may further include a plurality of reverse
locking elements and a third coupling member having a fourth
coupling face that opposes the second coupling face. The fourth
coupling face may have a set of reverse pockets angularly spaced
about the axis. Each of the reverse pockets may receive one of the
reverse locking elements and defines a reverse load-bearing surface
adapted for abutting engagement with a load-bearing surface of its
respective reverse locking element.
[0033] The reverse pockets may be grouped into at least one set
wherein the reverse pockets in each set are uniformly angularly
spaced.
[0034] The reverse pockets may be grouped into two or more
sets.
[0035] The assembly may further include a control member mounted
for controlled, shifting movement between the second and fourth
coupling faces relative to the set of reverse pockets and operable
for controlling position of the reverse locking elements. The
control member allows at least one of the reverse locking elements
to engage at least one of the reverse locking formations in a first
position of the control member wherein the control member maintains
the reverse locking elements in their pockets in a second position
of the control member.
[0036] The control member may comprise a slide plate controllably
rotatable about the rotational axis between the first and second
positions.
[0037] The assembly may further include a control element coupled
to the control member to controllably shift the control member.
[0038] The assembly may further include a generally round snap ring
that is received by an annular groove in the third coupling member
to retain the members together and prevent axial movement of the
members relative to one another.
[0039] Further in carrying out the above object and other objects
of at least one embodiment of the present invention, a controllable
clutch assembly having forward and reverse backlash is provided.
The assembly includes a plurality of forward locking elements. Each
of the forward locking elements has a load-bearing surface. The
assembly also includes at least one reverse locking element and
first and second clutch members supported for relative rotation
about a common rotational axis. The clutch members include a first
coupling face having a set of forward pockets angularly spaced
about the axis. Each of the forward pockets receives one of the
forward locking elements and defines a forward load-bearing surface
adapted for abutting engagement with the load-bearing surface of
its respective forward locking element. The members also include a
second coupling face which has a set of reverse locking formations
adapted for abutting engagement with the at least one reverse
locking element to prevent the relative rotation in a reverse
direction about the axis and a third coupling face that opposes the
first coupling face. The third coupling face has a set of forward
locking formations. Each of the set of forward locking formations
is adapted for abutting engagement with one of the forward locking
elements to prevent the relative rotation in a forward direction
about the axis. The number of forward locking formations is
different than the number of reverse locking formations. Either the
forward backlash is a non-zero integer multiple of the reverse
backlash or the reverse backlash is a non-zero integer multiple of
the forward backlash to prevent the coupling assembly from
inadvertently binding in both directions about the axis. The
forward pockets are grouped into at least one set wherein the
forward pockets in each set are uniformly angularly spaced.
[0040] The forward pockets may be grouped into two or more
sets.
[0041] Yet still further in carrying out the above object and other
objects of at least one embodiment of the present invention, a
controllable coupling assembly having forward and reverse backlash
is provided. The assembly includes a plurality of forward locking
elements. Each of the forward locking elements has a load-bearing
surface. The assembly also includes a plurality of reverse locking
elements. Each of the reverse locking elements has a load-bearing
surface. The assembly further includes first, second and third
coupling members supported for relative rotation about a common
rotational axis. The coupling members have a first coupling face
with a set of forward pockets angularly spaced about the axis. Each
of the forward pockets receives one of the forward locking elements
and defines a forward load-bearing surface adapted for abutting
engagement with the load-bearing surface of its respective forward
locking element. The members also have a second coupling face with
a set of reverse locking formations. Each of the set of reverse
locking formations are adapted for abutting engagement with one of
the reverse locking elements to prevent the relative rotation in a
reverse direction about the axis. A third coupling face opposes the
first coupling surface. The third coupling face has a set of
forward locking formations. Each of the set of forward locking
formations is adapted for abutting engagement with one of the
forward locking elements to prevent the relative rotation in a
forward direction about the axis. A fourth coupling face opposes
the second coupling face. The fourth coupling face has a set of
reverse pockets angularly spaced about the axis. Each of the
reverse pockets receives one of the reverse locking elements and
defines a reverse load-bearing surface adapted for abutting
engagement with a load-bearing surface of its respective reverse
locking element. The number of forward locking elements is
different than the number of reverse locking elements. The number
of forward locking formations is different than the number of
reverse locking formations. Either the forward backlash is a
non-zero integer multiple of the reverse backlash or the reverse
backlash is a non-zero integer multiple of the forward backlash to
prevent the coupling assembly from inadvertently binding in both
directions about the axis.
[0042] The reverse pockets may be grouped into at least one set
wherein the reverse pockets in each set are uniformly angularly
spaced.
[0043] The above object and other objects, features, and advantages
of the present invention are readily apparent from the following
detailed description of the best mode for carrying out the
invention when taken in connection with the accompanying drawings
and in view of the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is an exploded perspective view of a controllable
clutch or coupling assembly constructed in accordance with one
embodiment of the present invention;
[0045] FIG. 2 is a view similar to the view of FIG. 1 but taken
from a different direction to illustrate the bottom surfaces of the
assembly;
[0046] FIG. 3 is a top plan view of a coupling member of another
embodiment; and
[0047] FIG. 4 is a top plan view of a coupling member of yet
another embodiment.
DETAILED DESCRIPTION
[0048] As required, detailed embodiments of the present invention
are disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention that
may be embodied in various and alternative forms. The figures are
not necessarily to scale; some features may be exaggerated or
minimized to show details of particular components. Therefore,
specific structural and functional details disclosed herein are not
to be interpreted as limiting, but merely as a representative basis
for teaching one skilled in the art to variously employ the present
invention.
[0049] Referring now to the drawing figures, FIGS. 1 and 2 are
exploded perspective views (taken from different directions to
illustrate different surfaces of the components of the assembly) of
a controllable one-way clutch or coupling assembly, generally
indicated at 10, and constructed in accordance with one embodiment
of the present invention. The assembly 10 includes an annular
reverse pocket plate or first outer coupling member, generally
indicated at 12. An outer axially-extending surface 14 of the plate
12 has external splines 16 for coupling the plate 12 to the inner
surface of a transmission case (not shown). An inner radially
extending surface or coupling face 18 of the plate 12 is formed
with spaced pockets 20 in which reverse struts 22 are pivotally
biased outwardly by coil springs 27. Preferably, sixteen reverse
struts 22 are provided. However, it is to be understood that a
greater or lesser number of reverse struts may be provide as will
be described in greater detail herein below.
[0050] The assembly 10 also includes a control member or selector
slide plate, generally indicated at 26, having a plurality of
spaced apertures 28 extending completely therethrough to allow the
reverse struts 22 to pivot in their pockets 20 and extend through
the apertures 28 to engage spaced locking formations or ramped
reverse notches 30 formed in a radially extending surface or
coupling face 32 (FIG. 2) of an inner pocket plate or coupling
member, generally indicated at 34, when the plate 26 is properly
angularly positioned about a common central rotational axis 36 by a
shift fork or control element 38 which extends through a notch or
slot (not shown) formed through an outer circumferential end wall
42 of the plate 12. Preferably, 28 reverse notches are provided.
However, it is to be understood that a greater or lesser number of
reverse notches may be provided as will be described in greater
detail herein below.
[0051] The fork 38 is secured or coupled to the control plate 26 so
that movement of the fork 38 in the slot between different angular
positions causes the plate 26 to slide or shift between its control
positions to alternately cover or uncover the struts 22 (i.e., to
engage or disengage the reverse struts 22, respectively).
[0052] The plate 34 preferably comprises a splined ring having
internal splines 46 formed at its inner axially extending surfaces
48 (FIG. 2). A radially extending surface or coupling face spaced
from the surface 32 of the plate 34 has a plurality of spaced
pockets 52 (FIG. 1) formed therein to receive a plurality of
forward struts 54 therein which are pivotally biased by
corresponding coil springs 55. Preferably, fourteen forward struts
54 are provided. However, it is to be understood that a greater or
lesser number of forward struts may be provided as will be
described in greater detail herein below.
[0053] Referring collectively to FIGS. 1 and 2, assembly 10 also
includes a second outer coupling member or notch plate, generally
indicated at 58, which has a plurality of locking formations, cams
or notches 60 formed in a radially extending surface or coupling
face thereof by which the forward struts 54 lock the plate 34 to
the notch plate 58 in one direction about the axis 36 but allow
free-wheeling in the opposite direction about the axis 36.
Preferably, thirty two forward notches are provided. However, it is
to be understood that a greater or lesser number of forward notches
may be provided as will be described in greater detail herein
below.
[0054] The notch plate 58 includes external splines 64 which are
formed on an outer axial surface 66 of the plate 58 and which are
received and retained within axially extending recesses 68 formed
within an inner axially extending surface 70 of the end wall 42 of
the plate 12 (FIG. 1).
[0055] As shown in FIG. 1, the assembly 10 further includes a snap
ring, generally indicated at 72, having end portions 74 and which
fits within an annular groove 76 formed within the inner surface 70
of the end wall 42 of the plate 12 to hold the plates 12, 26, 34
and 58 together and limit axial movement of the plates relative to
one another.
[0056] The shift fork 38, in one control position of its control
positions, disengages the reverse struts 22. The shift fork 38 is
rotated about 7.degree. in a forward overrun direction about the
axis 36 to rotate the selector plate 26 to, in turn, allow the
reverse struts 22 to move from their disengaged positions in their
pockets 20 to their engaged positions with the notches 30.
[0057] As previously mentioned, many clutch assemblies (such as the
assembly 10 described in FIGS. 1 and 2 as well as the assemblies
300 and 400 described herein below with respect to FIGS. 3 and 4,
respectively) are meant to lock in one direction and lock or free
wheel in the opposite direction depending on the position of its
selector or selector plate. In certain clutch locations, the clutch
assembly would not come out of a "lock-lock" condition (i.e. would
inadvertently bind in both directions about the rotational axis).
This is due to the transitional backlash (i.e. distance the clutch
can move between forward and reverse directions) was extremely low.
This extremely low transitional backlash did not allow the locking
elements or struts to drop out of their locking or binding position
upon command thereby resulting in the "lock-lock" condition.
[0058] It was discovered for clutch assemblies having: 1) the
number of forward locking elements different than the number of
reverse locking elements; 2) the number of forward locking
formations different than the number of reverse locking formations;
and 3) either the forward backlash is a non-zero integer multiple
of the reverse backlash or the reverse backlash is a non-zero
integer multiple of the forward backlash that the coupling or
clutching assembly was prevented from inadvertently binding in both
directions about the rotational axis of its assembly.
[0059] When the above noted conditions are satisfied, the number of
forward and reverse locking elements and the number of forward and
reverse locking formations can be selected, so that minimum
transitional backlash is substantially equal in all positions. The
following table illustrates example possible combinations of
forward and reverse locking elements (struts) and forward and
reverse locking formations (notches):
TABLE-US-00001 Single/Dual Forward Single/Dual Reverse Function
Entry Forward Forward Strut Resolution Reverse Reverse Strut
Resolution without # Notches Struts Engagement (deg) Notches Struts
Engagement (deg) n tie-up? 1 36 14 Dual 1.4276 84 1 Single 4.2857 3
Yes 2 32 14 Dual 1.6071 28 16 Dual 1.6071 1 Yes 3 24 14 Dual 2.1429
28 12 Dual 2.1429 1 Yes 4 26 18 Dual 1.5385 78 1 Single 4.6154 3
Yes 5 32 14 Dual 1.6071 112 1 Single 3.2143 2 Yes 6 38 12 Dual
1.5789 36 10 Dual 2.0000 1.267 No 7 34 12 Dual 1.7647 26 14 Dual
1.9780 1.121 No
[0060] Entry #2 is represented in FIGS. 1 and 2. Entries 6 and 7
are examples of coupling assemblies which would experience the
"lock-lock" or binding condition. The type of "engagement" (either
"single" or "dual") indicates either a single or two struts provide
the locking function in one of the directions of rotation.
[0061] The above-noted discovery is applicable to any controllable
ratcheting clutch assembly both radial and planar configurations
such as the configurations shown in FIGS. 3 and 4. FIG. 3 shows a
planar concentric configuration of an assembly, generally indicated
at 300, including a reverse member or plate, generally indicated at
302, which is grounded at 301. The plate 302 has an outer surface
or coupling face 304 with reverse struts (not shown) in reverse
pockets 308 and an inner surface or coupling face 306 with forward
notches 310. The opposing clutch member which has the forward
pockets and struts, coupling faces, and the corresponding reverse
notches is not shown for simplicity. The resulting assembly 300 is
a dual engagement assembly having 6 reverse pockets, 44 reverse
notches (not shown), a reverse backlash of 2.727, 12 forward
pockets (not shown), 22 forward notches, a forward backlash of
2.727.degree. and a transitional backlash of 1.364.degree..
[0062] FIG. 4 shows a second planar concentric coupling assembly,
generally indicated at 400, including a reverse coupling member or
plate, generally indicated at 402, which is grounded at 401. The
plate 402 has an outer surface or coupling face 404 with reverse
struts (not shown) in reverse pockets 408 and an inner surface or
coupling face 406 with forward struts (not shown) in forward
pockets 410. The opposing coupling member or plate (not shown for
simplicity) has corresponding coupling faces and forward and
reverse locking formations. The resulting assembly 400 is a single
engagement assembly having 8 reverse pockets (and struts), 25
reverse notches (not shown), a reverse backlash of 1.8.degree., 4
forward pockets (and struts), 50 forward notches (not shown), a
forward backlash of 1.8.degree. and a transitional backlash of
0.9.degree..
[0063] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *