Title: Pressure plate assembly for a friction clutch
Abstract: A pressure plate assembly for a friction clutch includes a housing connectable with an abutment arrangement for rotation therewith about an axis of rotation. The housing has an outer axial side and an inner axial side. A pressure plate is mounted in the housing so that it faces the inner axial side. The pressure plate is rotatable with the housing about the axis of rotation. The pressure plate includes actuating sections which extend past a radially outer edge of the housing. An energy storage element is mounted on the outer side of the housing such that the energy storage device exerts a force on the actuating sections for urging the pressure plate away from the inner axial side. An assembly pretensioning arrangement is operative for holding the energy storage element in a pretensioned assembly position in which the energy storage device does not exert a force on the housing.
Patent Number: 6,986,415 Issued on 01/17/2006 to Mensch, et al.
| Inventors:
|
Mensch; Waldemar (Schweinfurt, DE);
Vogt; Sebastian (Bad Neustadt, DE);
Orlamünder; Andreas (Schweinfurt, DE)
|
| Assignee:
|
ZF Sachs AG (Schweinfurt, DE)
|
| Appl. No.:
|
718067 |
| Filed:
|
November 20, 2003 |
Foreign Application Priority Data
| Current U.S. Class: |
192/89.23; 192/70.13; 192/70.27; 192/109.R; 192/DIG.1; 29/446 |
| Current Intern'l Class: |
F16D 13/44 (20060101) |
| Field of Search: |
192/7013,702.7,892.7,109.R,DIG.1,892.3
|
References Cited [Referenced By]
U.S. Patent Documents
| 2256714 | Sep., 1941 | Hunt.
| |
| 4660695 | Apr., 1987 | Fukatani.
| |
| 4697685 | Oct., 1987 | Bancroft.
| |
| 4883153 | Nov., 1989 | Maucher et al.
| |
| 5002168 | Mar., 1991 | Hrubesch.
| |
| 5400887 | Mar., 1995 | Mizukami et al.
| |
| 5950786 | Sep., 1999 | Mahoney.
| |
| 6354418 | Mar., 2002 | Dalbiez.
| |
| 6409002 | Jun., 2002 | Orlamunder et al.
| |
| 2002/0144875 | Oct., 2002 | Dau et al.
| |
| Foreign Patent Documents |
| 42 22 045 | Jan., 1994 | DE.
| |
Primary Examiner: Lorence; Richard M.
Attorney, Agent or Firm: Cohen, Pontani, Lieberman & Pavane
Claims
What is claimed is:
1. A pressure plate assembly for a friction clutch, comprising:
a housing connectable with an abutment arrangement for rotation therewith about
an axis of rotation, the housing having an outer axial side and an inner axial side;
a pressure plate mounted in said housing facing said inner axial side such that
said pressure plate is rotatable with said housing, said pressure plate having
actuating sections extending past a radially outer edge of said housing;
an energy storage element mounted on said outer side of said housing such that
said energy storage device exerts an engaging force toward said housing and onto
said actuating sections for urging said pressure plate away from said inner axial side;
a plurality of spacer pins arranged on said housing for supporting said energy
storage element, each of said spacer pins including a support area at an end facing
away from said housing; and
an assembly pretensioning arrangement for holding said energy storage element
in a pretensioned assembly position in which the engaging force is prevented from
acting on said housing, said assembly pretensioning arrangement including at least
one assembly pretensioning element positioned between said energy storage element
and said supporting area of said each of said spacer pins so that a force feedback
of the energy storage element occurs through the spacer pins themselves when said
energy storage element is in the pretensioned assembly position, whereby the force
feedback is prevented from deforming the housing.
2. The pressure plate assembly of claim 1, wherein said at least one assembly
pretensioning element is an open ring-shaped element and is radially deformable
for producing and releasing the pretensioned assembly position.
3. The pressure plate assembly of claim 1, wherein said pressure plate assembly
is a multi-disk pressure plate assembly further comprising an intermediate plate
connected to said housing for rotation with said housing and said pressure plate
about said axis of rotation.
4. A process for bringing an energy storage element of a pressure plate assembly
of a friction clutch into a pretensioned assembly position and holding the energy
storage element in the pretensioned assembly position, the energy storage element
being connected on an outer axial side of the housing of the pressure plate assembly,
the method including the steps of
exerting a force on the energy storage element to bring the energy storage element
to a state of deformation which produces an intermediate space between the energy
storage element and a support area of a spacer pin which supports the energy storage
element on the housing;
inserting at least one assembly pretensioning element into the intermediate space; and
releasing the energy storage element so that the energy storage element arrives
in the pretensioned assembly position against the at least one assembly pretensioning
element and so that a force feedback of the energy storage element occurs through
the spacer pins themselves, whereby the force feedback is prevented from deforming
the housing.
5. In a pressure plate assembly having a housing connectable with an abutment
arrangement for rotation therewith about an axis of rotation, the housing having
an outer axial side and an inner axial side, a pressure plate mounted in said housing
facing said inner axial side such that said pressure plate is rotatable with said
housing, said pressure plate having actuating sections extending past a radially
outer edge of said housing, an energy storage element mounted on said outer side
of said housing such that said energy storage device exerts a force toward said
housing on said actuating sections for urging said pressure plate away from said
inner axial side, and a plurality of spacer pins arranged on said housing for supporting
said energy storage element, each of said spacer pins including a support area
at an end facing away from said housing, an assembly pretensioning element comprising
a ring-shaped pretensioning body with a break in its circumference, the break allowing
the assembly pretensioning element to be radially deformed to produce and to release
a pretensioned assembly state, said assembly pretensioning element being positionable
between said energy storage device and said supporting area of said each of said
spacer pins in the pretensioned assembly state so that a force feedback of the
energy storage device occurs through the spacer pins themselves when said energy
storage element is in a pretensioned assembly position, whereby the force feedback
is prevented from deforming the housing.
6. The assembly pretensioning element of claim 5, further comprising handle formations
at ends next to the break in the circumference to facilitate the radial deformation.
7. The assembly pretensioning element of claim 5, wherein said assembly pretensioning
element is made of wire.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a pressure plate assembly for a friction clutch,
the pressure plate assembly including a housing that is connectable to an abutment
arrangement for rotation in common around an axis of rotation, a pressure plate,
mounted in the housing and capable of rotating together with the housing around
the axis of rotation, and an energy storage element mounted on an outside surface
of the housing so that it exerts a force on actuating sections of the pressure
plate which extend across the edge of the housing.
2. Description of the Related Art
In pressure plate assemblies that are used in, for example, multi-disk friction
clutches in which several clutch disks are stacked axially in a row and the torque
to be transmitted via the clutch is transmitted via these several clutch disks,
the energy storage element, which is usually designed as a diaphragm spring or
disk spring, can be mounted on the outside surface of the housing to make more
efficient use of the available space. In the state before the pressure plate assembly
has been connected to an abutment arrangement such as, for example, a flywheel
or the like, there is no reactive force present to oppose the engaging force transmitted
by the energy storage element to the pressure plate. As a result, the energy storage
element will relax until, for example, it comes to rest against the radially outer
area of the housing. The engaging force exerted on the housing can deform the housing,
thereby creating difficulties when the attempt is made to connect the housing to
the abutment arrangement.
This potential deformation state is shown in simplified fashion in FIG. 5, which
shows the housing
12 of a pressure plate assembly
10. An energy storage
element
22 (shown, for example, as a diaphragm spring in FIG. 5) is arranged
on an outer axial side
14 of the housing
12 and is supported by several
spacer pins
16 and by two wire rings
18,
20. In the state
before the housing
12 has been connected to an abutment
24 (shown
schematically) the radially outer area of the energy storage element
22
exerts an engaging force as it relaxes on the radially outer area
26 of
the housing
12, with the result that these radially outer areas
26
of the housing
12 are deformed by the force feedback thus produced. The
sections
28 by which the housing is attached to the abutment may also deformed
or at least slightly tilted, which makes it much more difficult to perform the
assembly work. If, despite these difficulties, the housing
12 is bolted
to the abutment
24 in this state, the housing
12 can relax as soon
as the clutch thus assembled is disengaged the first time, and this can have the
result that the bolts used to connect the housing
12 to the abutment
24
are no longer firmly tightened and can proceed to loosen.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a pressure plate assembly and
a method of assembling the pressure plate assembly which ensures that the required
assembly work can be completed easily and reliably without the problems associated
with the prior art.
This object is accomplished according to the present invention by a pressure
plate assembly for a friction clutch which includes a housing that is connectable
to an abutment arrangement for rotation therewith about an axis of rotation, the
housing having an inner axial side, an outer axial side and a radially outer edge,
a pressure plate is mounted in the housing so that it faces the inner axial side
and so that it is rotatable together with the housing around the axis of rotation,
the pressure plate having actuating portions extending past the radially outer
edge. An energy storage element is mounted on the outer surface of the housing
so that it can exert an engaging force on the actuating sections of the pressure
plate which pass across the radially outer edge of the housing. An assembly pretensioning
arrangement for holding the energy storage element in a pretensioned assembly position
prevents the energy storage element from applying the engaging force to the housing.
The assembly pretensioning arrangement ensures that the energy storage element
is held in a suitable state in which the entire pressure plate assembly can be
mounted on an abutment arrangement. That is, the energy storage element is held
in a position in which it cannot exert an unfavorable engaging force on the housing
and cause its deformation.
The energy storage element may be supported by a plurality of carrier elements
on the housing and the assembly pretensioning arrangement may comprise at least
one assembly pretensioning element, by means of which the energy storage element
is supported with respect to at least one carrier element in the pretensioned assembly
position. This embodiment allows the energy storage element to be held in a simple
and defined manner against its own pretension in the pretensioned assembly position.
It can be provided, for example, that the at least one carrier element has a supporting
expansion head at the end of the at least carrier element facing away from the
housing and that the at least one assembly pretensioning element is positioned
between the energy storage element and the supporting expansion head when the energy
storage element is in the pretensioned assembly position.
A better distribution of the force required to hold the energy storage element
in the pretensioned assembly position may be achieved by designing the assembly
pretensioning element in the shape of a ring and by allowing it to interact with
several carrier elements to hold the energy storage element in the pretensioned
assembly position. The assembly pretensioning element preferably interacts with
all of the carrier elements.
The assembly pretensioning element may be designed as an open, ring-shaped element
capable of radial deformation to produce and release the pretensioned assembly
position. This configuration allows the pretensioned assembly position can be produced
and released very easily.
As already explained above, the present invention is especially effective when
the pressure plate assembly is a multi-disk pressure plate assembly including an
intermediate plate which is connected to the housing for rotation in common around
the axis of rotation.
The present invention also relates to a process for bringing an energy storage
element of a pressure plate assembly of a friction clutch mounted on an outside
surface of a housing into an pretensioned assembly position and for holding it
in that position. The inventive process includes the steps of exerting a force
on the energy storage element to bring the energy storage element into a state
of deformation corresponding approximately to a pretensioned assembly position,
inserting at least one assembly pretensioning element into an intermediate space
between the energy storage element and a supporting expansion head of at least
one of the carrier elements which supports the energy storage element on the housing,
and releasing the energy storage element so that it arrives in the pretensioned
assembly position and is held in the pretensioned assembly position by the at least
one assembly pretensioning element.
The present invention further relates to an assembly pretensioning element for
a pressure plate assembly for implementing the process according to the invention.
The assembly pretensioning element includes a ring-like pretensioning body with
a break in its circumference which makes it possible for the assembly pretensioning
element to be radially deformed for the production and release of the pretensioned
assembly state.
The ends of the assembly pretensioning element next to the break in the circumference
may be provided with actuating formations for the radial deformation to facilitate
manual deformation of the assembly pretensioning element.
The assembly pretensioning element may, for example, be made out of a wire material.
Other objects and features of the present invention will become apparent from
the following detailed description considered in conjunction with the accompanying
drawings. It is to be understood, however, that the drawings are designed solely
for purposes of illustration and not as a definition of the limits of the invention,
for which reference should be made to the appended claims. It should be further
understood that the drawings are not necessarily drawn to scale and that, unless
otherwise indicated, they are merely intended to conceptually illustrate the structures
and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, wherein like reference characters denote similar elements throughout
the several views:
FIG. 1 is a perspective view a pressure plate assembly of a multi-disk clutch
according to the present invention;
FIG. 2 is a partial longitudinal sectional view of the pressure plate assembly
of FIG. 1;
FIG. 3 is a partial axial view of an outer axial side of the pressure plate
assembly of FIG. 1;
FIG. 4 is a partial sectional view of the energy storage element of the pressure
plate assembly of FIG. 1 in the pretensioned assembly position; and
FIG. 5 is a partial sectional view of the energy storage element according to
the prior art in a state in which the absence of an opposing force allows the energy
storage element to exert an engaging force on the housing.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
With reference to FIGS. 1 and 2, a pressure plate assembly
10 for a multi-disk
clutch includes a housing
12 designed essentially in the form of a cup having
a bottom area
30. Adjacent to the radially outer edge of the bottom area
30, several sections
28 of the housing
12 are distributed
around the circumference. Threaded bolts can be passed through these sections to
fasten the housing
12 to an abutment plate (not shown in FIG. 1 and 2).
The entire housing
12, including its bottom area
30 and the sections
28, is formed by the shaping of sheet-metal stock.
A pressure plate
32 is mounted in the housing
12. The pressure
plate
32 includes radially outward-extending connecting projections
34
in several circumferential areas, which fit between the sections
28 of the
housing
12 to produce a connection with respect to rotation between the
housing
12 and the pressure plate
32. Accordingly, the housing
12
and pressure plate
32 rotate in common. The pressure plate
32 also
has several actuating sections
36, which pass across the radially outer
edge of the bottom area
30 of the housing
12. The radially outer
area
38 of the energy storage element
22, which is mounted on an
outer axial side
14 on the bottom area
30 of the housing
12,
exerts force on these actuating sections
36 and thus presses the pressure
plate
32 in the axial direction away from the bottom area
30 of the
housing
12.
The pressure plate assembly
10 also includes an intermediate plate
40
a certain axial distance away from the pressure plate
32. The intermediate
plate
40 also has connecting projections
42 in several circumferential
areas. In this way, the intermediate plate
40 is also connected to the housing
12 for rotation in common around the axis of rotation A. Friction lining
arrangements
44,
46 of two clutch disks or clutch disk areas
49,
50 are mounted between the pressure plate
32 and the intermediate
plate
34 on the one hand and between the intermediate plate
40 and
an abutment (not shown) on the other. The central hub area
52 of these clutch
disks
49,
50 is connected or connectable to a shaft (not shown) having
an axis of rotation so that the clutch disks can rotate in common. A releasing
force-producing arrangement
54 is supported between the abutment and the
intermediate plate
40 and also between the intermediate plate
40
and the pressure plate
32. The releasing force-producing arrangement
54
ensures that the intermediate plate
40 and the pressure plate
32
move far enough away from the surfaces which interact frictionally with them when
a clutch-releasing operation is performed.
As shown in FIG. 4, the energy storage element
22 is supported by plurality
of fastening pins
16, i.e., spacer pins, arranged in a row in the circumferential
direction on the bottom area
30 of the housing
12. These spacer pins
16 have expanded head areas or supporting areas
48 at the end of
the spacer pins
16 which face away from the bottom area
30. The two
wire rings
18,
20, already mentioned in connection with FIG. 5, pass
around the outside of the ring of spacer pins
16, so that the energy storage
element
22 is held axially between the bottom area
30, i.e., the
outer axial side
14 of the bottom area
30, and the supporting sections
48 of the spacer pins
16 and can therefore pivot around the contact
points with these wire rings
18,
20 during the performance of clutch-engaging
and clutch-releasing operations.
To avoid the problem described above associated with the prior art, that is,
to
prevent the radially outer area
38 of the energy storage element
22
from exerting an engaging force on the housing
12 in a state before it is
possible to generate an opposing force, an assembly pretensioning arrangement
56
is provided according to the invention. The pretensioning arrangement
56
comprises a ring-shaped element
58, formed out of wire, which forms a ring-shaped
body
66 that has a break
60 in its circumference. In the area of
this circumferential break, the ring-shaped element
58 has two actuating
sections
63,
64, which are produced by bending sections of wire out
from the plane of the ring-shaped body
66 and over so that they are essentially
perpendicular to that plane. The actuating sections
63,
64 represent
handles of the pretensioning arrangement
56. The ring-shaped element
58
can be designed so that its own elasticity pretensions it into a certain radial
configuration in which the ring-shaped body
66 has a dimension which, relative
to the axis of rotation A, i.e., central axis of the pressure plate assembly
10,
is at least slightly larger than a circular line defined by the radially inward-situated
side of the spacer pins
16.
To bring the energy storage element
22 into the pretensioned assembly
position
shown in FIG. 4, the radially inner area of the energy storage element
22
is subjected to a force relative to the housing
12 in the conventional manner
so that an intermediate space
62 (see FIG. 4) is produced between the support
sections
48 of the spacer pins
16 and the energy storage element
22. The two sections
63,
64 of the ring-shaped element
58
are then pulled together so that at least locally the radius of the ring-shaped
element
58 is decreased. While the ring-shaped element
58 is held
in this state, it is introduced into the intermediate spaces
62 produced
at the spacer pins
16. To make it easier to accomplish this insertion, the
energy storage element
22 is deformed to such an extent that these intermediate
spaces
62 are at first slightly oversized with respect to the diameter of
the ring-shaped element
58 of the ring-shaped body
66. Once the ring-shaped
element
58 has reached the position shown also in FIG. 1, the sections
63,
64 may be released which allows the ring-shaped element
58 to expand
radially. The ring-shaped body
66 now arrives in all of the other intermediate
spaces
62. When the energy storage element
22 is subsequently released,
the areas of the energy storage element
22 located radially inside the spacer
pins
16 move back again slightly in the direction away from the bottom
30
of the housing
12, until they come to rest against the ring-shaped body
66 of the ring-shaped element
58. In this state, the ring-shaped
element
58 prevents further relaxation of the energy storage element
22
which is also supported by the wire ring
20 supported on the outer axial
side
14 of the bottom area
30. The force feedback occurs via the
spacer pins
16 themselves, so that it is impossible for a force large enough
to deform the housing
12 to be introduced into it.
In the pretensioned assembly state shown in FIG. 4, an axial gap is arranged
between
the radially outer area
38 of the energy storage element
22 and the
housing
12. When the pressure plate assembly
10 is brought up to
its abutment, the housing
12 may be positioned correctly on this abutment
and connected to it using threaded connectors such as, for example, screws. After
these two components have been connected together, the ring-shaped element
58
may be removed by first exerting force on the radially inner part of the energy
storage element
22 to release its clamping action on the ring-shaped body
66. Then the sections
63,
64 of the ring-shaped element
58
may be pulled toward each other again, so that the ring-shaped element
58
emerges from some of the intermediate spaces
62. By tilting and pulling,
the ring-shape element may be removed from all of the other intermediate spaces
62.
It should be pointed out that the clamping action between the energy storage
element
22 and the spacer pins
16 described above could also be accomplished
by other types of intermediate elements. In particular, it is not mandatory to
use a single element of this type.
For example, it would be possible to use a separate assembly pretensioning element
on one or more of the spacer pins
16.
The assembly pretensioning arrangement
56, as described above, may be
used to advantage not only the first time that the pressure plate assembly is put
together but also, as should be obvious, when it is necessary to make repairs.
In all cases, the advantage is obtained that the pressure plate assembly
10
does not have to be connected to its abutment while it is being subjected to the
force produced by the energy storage element
22.
The pressure plate assembly shown in the figures is obviously only one example
of a pressure plate assembly to which the principles of the invention can be applied.
Many parts of the pressure plate assembly such as the energy storage element, the
pressure plate, and the intermediate plate can be modified. It is obvious, for
example, that the sections
36 extending past the edge of the housing could
also be components of the energy storage element, the radially outer area of which
would be provided with corresponding deformations or fastened-on parts. The housing
could also be designed differently. For example, its outer circumferential area
could have a flange-like section, by means of which it is connected to an abutment
plate or the like. In addition, the connection of the pressure plate and possibly
of an intermediate plate to the housing for rotation in common could be accomplished
in some other way such as, for example, by the use of tangential leaf springs or
other connection which prevent relative rotation but allow limited axial movement.
Thus, while there have shown and described and pointed out fundamental novel
features of the invention as applied to a preferred embodiment thereof, it will
be understood that various omissions and substitutions and changes in the form
and details of the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the invention. For
example, it is expressly intended that all combinations of those elements and/or
method steps which perform substantially the same function in substantially the
same way to achieve the same results are within the scope of the invention. Moreover,
it should be recognized that structures and/or elements and/or method steps shown
and/or described in connection with any disclosed form or embodiment of the invention
may be incorporated in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention, therefore, to be limited
only as indicated by the scope of the claims appended hereto.
*
