Claims:We claim
1. A pressure plate (30a, 30b) for use in a clutch mechanism which provides
torque transfer between the engine flywheel and the gear box in motorized
vehicles, made of cast steel comprising an annular body 5 (31) with an axis
of rotation (X) and a plurality of tabs (32) extending radially from the
outer periphery (33) of the pressure plate, the tab (32) comprising a lateral
centering surface (34) arranged to press on a clutch cover, the connection
of the tabs (32) with the annular body (31) comprises a necking region
10 (35) obtained as raw foundry, the necking region (35) forming the
junction between the lateral centering surface (34) and the outer periphery
(33) of the pressure plate. (30a, 30b).
2. A pressure plate (30a, 30b) according to claim 1, wherein said necking
region (35) forms a cavity (35a) whose bottom is rounded to limit the
15 concentrations of mechanical stress.
3. A pressure plate (30a, 30b) according to claim 1 or 2, wherein said lateral
centering surface (34) is a machined surface.
4. A pressure plate (30a, 30b) according to one of the claims 1 to 3, wherein
said lateral centering surface (34) has a rectangular shape.
20 5. A pressure plate (30a, 30b) according to one of the claims 1 to 3, wherein
said lateral centering surface (34) has a trapezoidal shape.
6. A pressure plate (30a, 30b) according to one of the claims 1 to 5, wherein
said lateral centering surface (34) comprises a recess (39) able to contain
lubrication grease.
25 7. A pressure plate (30a, 30b) according to any one of the preceding claims,
wherein said tab (32) comprises a hole (36) arranged to receive an
actuation rod, the necking region (35) is distributed on both sides of the
tab (32), symmetrically in relation to the plane (P-P) passing through the
axis of rotation and through the axis of the hole.
13
8. A pressure plate (30a, 30b) according to the preceding claim, wherein two
lateral centering surfaces (34) are distributed symmetrically from the
plane (P-P) passing through the axis of rotation and through the axis of
the hole.
9. A pressure plate (30a, 30b) according to the preceding claim, 5 wherein said
two lateral centering surfaces (34) are parallel.
10. A pressure plate (30a, 30b) according to any one of the preceding claims,
wherein said annular body (31) of the pressure plate comprises on one
side a friction face (37) arranged to rub on a clutch disc and on the other
10 side a support cord (38) arranged to cooperate with an elastic load
application washer.
11. A dual clutch mechanism (1) having a clutch cover (40), which is able to
couple to a drive shaft of the motor vehicle engine and which serves for
the introduction of the torque, having a first clutch part (10) for the
15 coupling of the clutch cover (40) to the first driven shaft, wherein the first
clutch part (10) has a first clutch disk (11) and a first pressure plate (30a)
according to anyone of the preceding claims, and having a second clutch
part (20) for the coupling of the clutch cover (2) to the second driven
shaft, wherein the second clutch part (20) has a second clutch disk (12)
20 and a second pressure plate (30b) according to anyone of the preceding
claims, wherein the clutch cover (40) comprises peripheral openings (41)
into which the tabs of the first pressure plate and the tabs of the second
pressure plate are inserted.
12. A dual clutch mechanism (1) according to claim 11, wherein said first
25 clutch part (10) comprises a plurality of levers (18) which, in order to
actuate the first pressure plate (30a), are each coupled to an actuating rod
(13), the end (14) of each actuating rod is inserted into a hole (36a)
provided into each tab of the first pressure plate.
14
13. A dual clutch mechanism (1) according to claim 11, the second clutch part
(20) comprises a plurality of levers (28) which, in order to actuate the
second pressure plate (30b), are each coupled to an actuating rod (23), the
end (24) of each actuating rod (13) is inserted into a hole (36b) provided
into each tab of the second 5 pressure plate.
14. A dual clutch mechanism (1) according to one of the claims 11 to 13,
wherein said peripheral openings (41) of the clutch cover comprises a
least one lateral bearing surface (42) facing the lateral centering surface
(34) of the tab and adapted to limit the angular displacement of the
10 pressure plate.
15. A dual clutch mechanism (1) according to the preceding claim, wherein
said lateral bearing surface (42) is partially housed in the cavity formed
by the necking region (35) without contact between the two components.
16. A clutch mechanism (1) having a clutch cover (40), which is able to
15 couple to a drive shaft of the motor vehicle engine and which serves for
the introduction of the torque, having a clutch part (10) for the coupling of
the clutch cover (40) to the driven shaft, wherein the clutch part (10) has a
clutch disk (11) and a pressure plate (30a) according to anyone of the
claims 1 to 10, wherein the clutch cover (40) comprises peripheral
20 openings (41) into which the tabs (32) of the pressure plate are inserted. , Description:TECHNICAL FIELD
The present invention relates to an improve pressure plate use in a friction clutch
unit and a friction clutch unit comprising this improve pressure plate. Such
friction clutch unit is positioned between an engine and 5 transmission, for
example a thermal engine or electrical engine, and a set of one or more driving
wheels of a vehicle. Friction clutch units of the type indicated are used, in
particular, although not exclusively, in the field of agricultural tractors, for the
engagement of the transmission to the wheels and of the transmission to the
10 power take-off shaft. Friction clutch units of the type indicated are also used, in
particular, in the field of heavy-duty trucks.
PRIOR ART
15 A friction clutch unit used in the field of agricultural tractors are known from
document US4465170, which will be discussed hereafter.
Friction clutch unit are used for engaging the powertrain and the engine in
vehicles or for disengaging the present connection. Friction clutch unit connects
the engine flywheel and the input shaft of the gearbox and disengages this
20 connection by means of pressing the clutch pedal. Friction clutch unit also
connects the engine flywheel and the power take-off shaft and disengages this
connection by means of pressing the clutch pedal. The torque is transmitted by a
clutch disc clutched between a pressure plate and a clutch cover.
According to the document US4465170, the friction clutch unit which governs
25 the engagement of the transmission to the power take-off shaft, the P.T.O shaft
in brief, is of the normally engaged type, that is, a connection is normally
established between the driving member and the P.T.O shaft inside the machine
unless the operator operates the lever linkage which controls the operation of the
clutch, disengaging the connection. The transmission comprises a bearing sleeve,
3
which allows the P.T.O shaft to be disconnected outside the machine when it is
not expected to be used.
During the disengagement phase, the pressure plate moves axially with regard to
the clutch cover. The pressure plate is centered onto the clutch cover by using
several tabs extending radially from the annular body of the pressure 5 plate. The
tabs moves into peripheral openings adapted in the clutch cover and slides onto
lateral bearing surfaces facing the lateral centering surfaces of the tab. The
mounting of the tabs inside the cover openings requires great assembly precision
and consequently requires complete machining of the component surfaces
10 located near this area. The tabs of the pressure plate are totally machined in the
proximity of the peripheral openings of the clutch cover. This solution is
expensive and time consuming in terms of manufacturing.
Within this context, the tabs of the pressure plate need to be totally machined in
the proximity of the peripheral openings of the clutch cover and lead to increase
15 in the total production cost of the friction clutch unit.
As a result, because of all of the abovementioned problems, an improvement is
required in the related technical field.
BRIEF DESCRIPTION OF THE INVENTION
20
The present invention relates to an improve pressure plate for use in a friction
clutch unit, as for example a tractor clutch, for eliminating the above mentioned
disadvantages and for bringing new advantages to the related technical field.
To this end, the invention proposes an improve pressure plate with a specific
25 shape for the tabs which is simple to implement.
In order to realize all of the abovementioned objects and the objects which are to
be deducted from the detailed description below, the present invention is a
pressure plate for use in a clutch mechanism which provides torque transfer
between the engine flywheel and the gear box in motorized vehicles, made of
4
cast steel comprising an annular body with an axis of rotation X and a plurality
of tabs extending radially from the outer periphery of the pressure plate, the tab
comprising a lateral centering surface arranged to press on a clutch cover, the
connection of the tabs with the annular body comprises a necking region
obtained as raw foundry, the necking region forming the junction 5 between the
lateral centering surface and the outer periphery of the pressure plate.
This pressure plate according to the invention has the advantage of enlarging the
space available between the tabs and the clutch cover without reducing the
mechanical strength and the reliability of friction clutch unit. The necking region
10 is a localized thinning of the tab obtained directly by foundry casting. The
necking region creates a free space between the tab of the pressure plate and the
clutch cover increasing the geometrical clearance in this area. Thanks to the
invention, the length of the machined surface of the tabs are reduce.
15 The invention can exhibit one or another of the characteristics described below,
combined with one another or taken independently of one another.
In a preferred embodiment of the present invention, the necking region forms a
cavity whose bottom is rounded to limit the concentrations of mechanical stress.
20 In a preferred embodiment of the present invention, the lateral centering surface
is a machined surface.
In a preferred embodiment of the present invention, the lateral centering surface
has a rectangular shape.
In a preferred embodiment of the present invention, the lateral centering surface
25 has a trapezoidal shape.
In a preferred embodiment of the present invention, the lateral centering surface
comprises a recess able to contain lubrication grease.
In a preferred embodiment of the present invention, the tab comprises a hole
arranged to receive an actuation rod, the necking region is arranged on both
5
sides of the tab, symmetrically in relation to the plane passing through the axis
of rotation and through the axis of the hole.
In a preferred embodiment of the present invention, two lateral centering
surfaces are distributed symmetrically from the plane passing through the axis of
rotation and through the 5 axis of the hole.
In a preferred embodiment of the present invention, the two lateral centering
surfaces are parallel.
In a preferred embodiment of the present invention, the annular body of the
pressure plate comprises on one side a friction face arranged to rub on a clutch
10 disc and on the other side a support cord arranged to cooperate with an elastic
load application washer.
The invention also relates, according to another of its aspects, to a dual clutch
mechanism having a clutch cover, which is able to couple to a drive shaft of the
15 motor vehicle engine and which serves for the introduction of the torque, having
a first clutch part for the coupling of the clutch cover to the first driven shaft,
wherein the first clutch part has a first clutch disk and a first pressure plate
taking all or some of the aforementioned features, and having a second clutch
part for the coupling of the clutch cover to the second driven shaft, wherein the
20 second clutch part has a second clutch disk and a second pressure plate taking all
or some of the aforementioned features, wherein the clutch cover comprises
peripheral openings into which the tabs of the first pressure plate and the tabs of
the second pressure plate are inserted.
In a preferred embodiment of this aspect of the present invention, the first clutch
25 part comprises a plurality of levers which, in order to actuate the first pressure
plate, are each coupled to an actuating rod, the end of each actuating rod is
inserted into a hole provided into each tab of the first pressure plate.
In a preferred embodiment of this aspect of the present invention, the second
clutch part comprises a plurality of levers which, in order to actuate the second
6
pressure plate, are each coupled to an actuating rod, the end of each actuating
rod is inserted into a hole provided into each tab of the second pressure plate.
In a preferred embodiment of this aspect of the present invention, the peripheral
openings of the clutch cover comprises a least one lateral bearing surface facing
the lateral centering surface of the tab and adapted to 5 limit the angular
displacement of the pressure plate.
In a preferred embodiment of this aspect of the present invention, the lateral
bearing surface is partially housed in the cavity formed by the necking region
without contact between the two components.
10 The invention also relates, according to another of its aspects, to a clutch
mechanism having a clutch cover, which is able to couple to a drive shaft of the
motor vehicle engine and which serves for the introduction of the torque, having
a clutch part for the coupling of the clutch cover to the driven shaft, wherein the
clutch part has a clutch disk and a pressure plate taking all or some of the
15 aforementioned features, wherein the clutch cover comprises peripheral
openings into which the tabs of the pressure plate are inserted.
BRIEF DESCRIPTION OF THE FIGURES
20 Figure 1 is the general assembly view of the dual clutch mechanism according to
the first embodiment of the invention.
Figure 2 is the cross sectional view of the dual clutch mechanism according to
the Figure 1.
25
Figure 3 is the isometric view of the dual clutch mechanism according to the
Figure 1.
7
Figure 4 is the detail view of the pressure plate according to the first
embodiment of the invention.
Figure 5 is the detail view of the pressure plate according to a second
embodiment 5 of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In this detailed description, the subject matter pressure plate 30a, 30b for use in
10 a friction clutch unit is explained with references to examples without forming
any restrictive effect only in order to make the subject more understandable.
Figures 1 to 4 illustrate a friction clutch unit 1 comprising the pressure plate 30a,
30b according to a first embodiment of the invention. The friction clutch unit1 is
a dual clutch mechanism having a first clutch part 10 and a second clutch part
15 20. The friction clutch unit 1 is fixed onto a flywheel 2.
The first clutch part 10 is used for the control of movement transfer from the
thermal engine to the driving wheels of the vehicle and the second clutch part 20
is used for the control of movement transfer from the thermal engine to power
take-off shaft. In the present case, the dual clutch mechanism 1 is a tractor
20 clutch.
Accordingly, into the first clutch part 10, the torque received from the thermal
motor is transferred to the tail axle by means of friction between a first pressure
plate 30a and a first clutch disc 11 connected to the gearbox.
In an exemplary embodiment of said friction clutch unit 1, said pressure plate
25 30a is positioned between the first clutch disc 11 and a clutch cover 40. In order
to actuate the first pressure plate 30a, a plurality of levers 18 are coupled to
actuating rods 13. Each lever 18 is connected onto the clutch cover 40 by means
of a pin 16 so as to have rotation freedom. The actuating rod 13 connected to
said lever 18 from one side, and connected to the pressure plate 30a from the
8
other side is able to be actuated for clutching or declutching. For clutching or
declutching, the lever 18 moves in the movement axis X by means of the force
applied onto the lever 18, and pushes the pressure plate 30a away from the first
friction disc 11.
The clutch cover 40 has a body portion in circular form around 5 an axis X and
comprises a frictional surface 43. The first clutch disc 11 located inside of the
clutch cover 40 rubs onto the frictional surface 43 of the clutch cover 40. During
clutching operation, the friction between the first clutch disc 10 and the
frictional surface 43 creates warm-up of the clutch cover 40.
10
According to the first embodiment of the invention, the pressure plate 30a made
of cast steel comprises an annular body 31 with an axis of rotation X and a
plurality of tabs 32 extending radially from the outer periphery 33 of the
pressure plate. The annular body 31 of the pressure plate comprises on one side
15 a friction face 37 arranged to rub on the second clutch disc 12 and on the other
side a support cord 38 arranged to cooperate with an elastic load application
washer 3.
The clutch cover 40 comprises peripheral openings 41 into which the tabs 32 of
the first pressure plate 30a are inserted. The peripheral openings 41 comprises
20 two lateral bearing surfaces 42 facing the lateral centering surfaces 34 of the tab
and adapted to limit the angular displacement of the pressure plate. During the
disengagement phase, the tabs 32 moves into the peripheral openings 41 and
slides onto the lateral bearing surfaces 42.
As illustrated in Figure 4, the tab 32 of the first pressure plate 30a comprises a
25 lateral centering surface 34 arranged to press on the clutch cover 40, the
connection of the tabs 32 with the annular body 31 comprises a necking region
35 obtained as raw foundry. The tab 32 comprises a hole 36 arranged to receive
the actuation rod 13. The necking region 35 is distributed on both sides of the
9
tab, symmetrically in relation to a plane P-P passing through the axis of rotation
and through the axis of the hole.
The necking region 35 forms the junction between the lateral centering surface
34 and the outer periphery 33 of the pressure plate 30a. 5 According to the
invention, the necking region 35 enlarges the space available between the tabs
and the peripheral openings 41 of the clutch cover 40 without reducing the
mechanical strength and the reliability of friction clutch unit 1. The necking
region 35 is a localized thinning of the tab obtained directly by foundry casting.
10 The necking region 35 creates a free space between the tab of the pressure plate
and the clutch cover increasing the geometrical clearance in this area.
The necking region 35 forms a cavity 35a whose bottom is rounded to limit the
concentrations of mechanical stress. Also, the lateral centering surface 34 is a
machined surface. The two lateral centering surfaces 34 are distributed
15 symmetrically from the plane P-P passing through the axis of rotation and
through the axis of the hole 36. The two lateral centering surfaces 34 are
parallel.
For example, as illustrated in Figure 4, the lateral centering surface 34 has a
trapezoidal shape. The lateral centering surface 34 could have a rectangular
20 shape.
For example, as illustrated in Figure 5, the lateral centering surface 34 comprises
a recess 39 able to contain lubrication grease. The grease makes it easy to slide
the pressure plate off the clutch cover.
The second clutch part 20 is used for the control of movement transfer from the
25 thermal engine to power take-off shaft of the vehicle. Accordingly, into the
second clutch part 20, the torque received from the thermal motor is transferred
10
to the power take-off shaft by means of friction between a second pressure plate
30b and a second clutch disc 12 connected to the P.T.O shaft.
In an exemplary embodiment of said friction clutch unit 1, said pressure plate
30b is positioned between the second clutch disc 12 and an elastic load
application washer 3. In order to actuate the second pressure 5 plate 30b, a
plurality of levers 28 are coupled to actuating rods 23. Each lever 28 is
connected onto the clutch cover 40 by means of a pin 16 so as to have rotation
freedom. The actuating rod 23 connected to said lever 28 from one side, and
connected to the pressure plate 30b from the other side is able to be actuated for
10 clutching or declutching. For clutching or declutching, the lever 28 moves in the
movement axis X by means of the force applied onto the lever 28, and pull the
pressure plate 30b away from the second clutch disc 12. Intermediate pins 27 are
inserted between levers 28 and actuating rods 23.
Inside of the clutch cover 40, the first pressure plate 30a and the second pressure
15 plate 30b are separated by an elastic load application washer 3. The elastic
washer 3 applies the axial load onto the cord 38 of the pressure plate.
According to the first embodiment of the invention, the pressure plate 30b made
of cast steel comprises an annular body 31 with an axis of rotation X and a
plurality of tabs 32 extending radially from the outer periphery 33 of the second
20 pressure plate. The annular body 31 of the pressure plate comprises on one side
a friction face 37 arranged to rub on the second clutch disc 12 and on the other
side a support cord 38 arranged to cooperate with the elastic load application
washer 3.
The clutch cover 40 comprises peripheral openings 41 into which the tabs 32 of
25 the first pressure plate 30a are inserted.
As illustrated in Figure 3, the tab 32 of the second pressure plate 30b comprises
a lateral centering surface 34 arranged to press on the peripheral openings 41 of
the clutch cover 40, the connection of the tabs 32 with the annular body 31
comprises a necking region 35 obtained as raw foundry.
11
There will now be described, with reference to Figure 5, a pressure plate 30a
according to a second embodiment of the invention in which the lateral
centering surface 34 comprises a recess 39 able to contain lubrication grease.
The grease enable the lubrication of the contact between the 5 tabs 32 and the
peripheral openings 41. The axial movement of the pressure plate is improved.
This second embodiment is distinguished from that explained with reference to
Figure 4 in that the lateral centering surface 34 is divided in two surfaces
parallel. The recess 39 is smaller than the striction of the matter 35 but is also
10 obtained directly by foundry casting. In an other embodiment, the recess can be
machined.
The protection scope of the present invention is set forth in the annexed claims
and cannot be restricted to the illustrative disclosures given above, under the
detailed description. It is because a person skilled in the relevant art can
15 obviously produce similar embodiments under the light of the foregoing
disclosures, without departing from the main principles of the present invention.