Claims:Claims
We claim:
1. A retainer plate (4) (15) for a damper (18) of a vehicle clutch, comprising:
· a plurality of windows (19) adapted to receive damping springs (10), the plurality of windows being distributed around an axis of rotation of the retainer plate,
· at least one protrusion (21) extending circumferentially on one side of the retainer plate, the at least one protrusion being located radially outward to one of the said window (19), the protrusion (21) creating a groove (Ga) (Gb) in the opposite side of the retainer plate (4) (15).
2. Retainer plate as claimed in claim 1 wherein each protrusion (21) is located at the periphery of the retainer plate.
3. Retainer plate as claimed in claim 1 wherein each protrusion is radially spaced from the periphery of the retainer plate, a distance (Db) separating the periphery of the retainer plate and the protrusion (21b).
4. Retainer plate as claimed in claim 1 wherein, one protrusion (21) is associated to each window (19).
5. Retainer plate as claimed in claim 4 wherein each protrusion (21) is radially spaced from its window towards the periphery of the retainer plate.
6. Retainer plate as claimed in claim 4 wherein, each window (19) is bordered radially outward by a window eyelid (20) which is adapted to retain axially the damping spring (10) and each protrusion (21) is located radially outward to the window eyelid (20).
7. Retainer plate as claimed in claim 5 wherein the protrusions (21) and the eyelids protrudes in the same side of the retainer plate (4, 15).
8. Retainer plate as claimed in claim 1 comprising connection slots (22) located circumferentially between two nearby windows (19).
9. Retainer plate as claimed in claim 7 wherein at least a part of the connection slots (22) and the at least one protrusion (21) are located at the same radial distance of the axis of rotation.
10. Retainer plate as claimed in claim 1 wherein the retainer plate is formed in a steel sheet, and protrusions (21) are formed directly in the steel sheet, for example by stamping.
11. A damper for a drivetrain of a vehicle, the damper comprising at least one retainer plate as claimed in claims 1 to 9,
12. A damper as claimed in claim 10, the damper comprising
- two retainer plates , each window opening (19) of each retainer plate receiving a damping spring (10) and the two retainer plates being rigidly connected to each other with at least one connection element (7) , the two retainer plates (4, 15) having the same axis of rotation,
- a drive plate (5), the drive plate having recesses receiving the damping springs (10), the drive plate being axially located between the two retainer plates and the drive plate being able to rotate in relation to the two retainer plates (4, 15) according to the axis of rotation of the retainer plates (4, 15) when the damping springs (10) are working.
13. The damper as claimed in claim 11 wherein the damper comprises an angular stopping device arranged on the two retainer plates (4, 15) and the drive plate (5), the angular stopping device and at least a part of the protrusion (21) being located at the same radial distance of the axis of rotation.
14. The damper as claimed in claim 11 wherein the at least one connection element (7) of the two retainer plates (4, 15) and at least a part of the protrusion (21) are located in the same radial distance of the axis of rotation.
15. The damper as claimed in claim 11 wherein the at least one connection element of the two retainer plates (4, 15) is located circumferentially between two nearby windows (19).
, Description:Field of Invention
[001] The present invention relates to an automobile clutch damper assembly, and more particularly it deals with the spring retainer plate construction.

Background of Invention
[002] In the vehicle clutch damper assembly, the retainer part plays a major role in torque transfer between friction disc and drive plate. In the torque transfer between retainer plate and drive plate, damping spring acts as a buffer medium. Spring action is the key element to transmit torque from the retainer plate to the drive plate. The hub connected to the drive plate transmit the torque to the gearbox input shaft. At high speed a centrifugal force is being evolved around the spring window of the retainer plate. The peripheral region outward to the spring window of the retainer plate has the least metal body and acts as a weaker region. The frequent centrifugal force hitting on the weaker region of the retainer plate can lead to a crack or a damage.

[003] The present invention focuses on increasing the stiffness of the peripheral region outward to the spring window.

Objective of the Invention
[004] The main objective of the invention is to increase stiffness of the retainer plate outward of the spring window opening.
[005] Another objective of the invention is to increase stiffness without addition of any material.
[006] Further objective of the invention is to increase stiffness of the retainer plate by a simple process of stamping without additional process involving.

Summary of the Invention
[007] The clutch containing friction disc, damper assembly connected with a gearbox input shaft via hub. For example, the friction disc has an engine side friction plate, a gearbox side friction plate and a cushion disc riveted between the engine side and gearbox side friction plates.

[008] The engine side friction plate and gearbox side friction plate are axially compressed between flywheel and pressure plate when the clutch engaged.

[009] The cushion disc transfers torque from the friction plates 1a, 1b to the retainer plates using rivet joints. The torque from at least one or two riveted retainer plates is transmitted to a drive plate via the spring intervening between them.
[010] A huge centrifugal force can emerge around the window opening of the retainer plates, in particular at high speed. The torsional driving spring force and/or centrifugal force has a potential to damage the weaker peripheral region outward of the spring window opening of the retainer plate.

[011] The present invention proposes a protrusion in this weaker region of the retainer plate to provide mechanical strength to withstand larger centrifugal force.
[012] At that end, the present invention concerns a retainer plate for a damper of a vehicle clutch, comprising:
· a plurality of windows adapted to receive damping springs, the plurality of windows being distributed around an axis of rotation of the retainer plate,
· at least one protrusion extending circumferentially on one side of the retainer plate, the at least one protrusion being located radially outward to one of the said window, the protrusion creating a groove in the opposite side of the retainer plate.
[013] Preferably, each protrusion is located at the periphery of the retainer plate.
[014] Preferably, each protrusion is radially spaced from the periphery of the retainer plate, a distance separates the periphery of the retainer plate and the protrusions.
[015] Preferably, one protrusion is associated to each window.
[016] Preferably, each protrusion is radially spaced from its window towards the periphery of the retainer plate.
[017] Preferably, each window is bordered radially outward by a window eyelid which is adapted to retain axially the damping spring and each protrusion is located radially outward to the window eyelid.
[018] Preferably, the protrusions and the eyelids protrudes in the same side of the retainer plate.
[019] Preferably, the retainer plate comprises connection slots located circumferentially between two nearby windows.
[020] Preferably, at least a part of the connection slots and the at least one protrusion are located at the same radial distance of the axis of rotation.
[021] Preferably, the retainer plate is formed in a steel sheet, and protrusions are formed directly in the steel sheet, for example by stamping.
[022] The invention also refers to a damper for a drivetrain of a vehicle, the damper comprising at least one retainer plate as laid out above.
[023] Preferably, the damper comprises:
- two retainer plates, each window opening of each retainer plate receiving a damping spring and the two retainer plates being rigidly connected to each other with at least one connection element, the two retainer plates having the same axis of rotation,
- a drive plate, the drive plate having recesses receiving the damping springs, the drive plate being axially located between the two retainer plates and the drive plate being able to rotate in relation to the two retainer plates according to the axis of rotation of the retainer plates when the damping springs are working.
[024] Preferably, the damper comprises an angular stopping device arranged on the two retainer plates and the drive plate, the angular stopping device and at least a part of the protrusion being located at the same radial distance of the axis of rotation.
[025] Preferably, at least one connection element of the two retainer plates and at least a part of the protrusion are located in the same radial distance of the axis of rotation.
[026] Preferably, the at least one connection element of the two retainer plates is located circumferentially between two nearby windows.
Brief Description of Drawings
[027] Figure 1 shows an exploded view of a clutch damper assembly, in accordance with an embodiment of the present invention;
[028] Figure 2 shows a front view of a retainer plate of the clutch damper assembly of Figure 1;
[029] Figure 2A shows the retainer plate with at least one protrusion on the periphery, showing its height, depth and width; and
[030] Figure 2B shows the retainer plate with a protrusion between periphery and the window opening with a protrusion clearance from the periphery, and showing protrusion height, depth and width.

Detailed Description of the Preferred Embodiment:
[031] The present invention relates to the geometry of the retainer plates of a clutch damper assembly.

[032] The clutch damper assembly as shown in figure 1 contains friction disc arrangement (1) and a damper assembly.

[033] The friction disc arrangement contains two friction plates 1a and 1b, the first friction plate (1a) facing engine and the second friction disc facing the gearbox side (1b).

[034] The friction disc contains also a cushion disc (3) riveted within the two friction plates (1a) (1b) and extending inwardly to rivet with a retainer plate.

[035] In figure 1, the damper assembly contains two retainer plates (4) (15), one drive plate (5) and damping springs (10) (14).

[036] The one or more retainer plates are of circular body containing a hub slot (24), a plurality of radially distributed windows (19) cooperating with the damping springs (10), a connection slot (22) and a protrusion (21) towards periphery of the window (19). A rivet (7) has a first extremity inserted in a connection slot of one of the two retainer plates and a second extremity inserted in a connection slot of the other of the two retainer plates.
[037] The hub (13) is used to couple the gearbox input shaft with the damping assembly for the torque transfer. The plurality of windows (19) in the retainer plate (4) (15) are adapted to receive damping springs (10) (14) and are distributed radially outward an axis of rotation of the retainer plate. The connection slots (22) to rivet the retainer plates are distributed along the circumference of the plate.

[038] A drive plate (5) and a central hub (13) (coupled with gearbox input shaft) transfer torque from the retainer plate to the gearbox. The drive plate is being placed between the retainer plates (4) & (15). The torque from the retainer plates (4) (15) is transmitted to a drive plate (5) via the spring (10) (14) intervening between them. Also the retaining plate joining rivet (7) p acts also as a stopper in either direction of the drive plate movement to prevent an excessive compression of the springs retain the spring qualities.

[039] A first embodiment of the invention is shown in the figure 2. A protrusion (21) extending circumferentially and located on one face of the retainer plate, radially outward to one of the spring window (19), creating a groove (Ga) in the opposite of the retainer plate (4) (15). Each protrusion (21) is extending circumferentially at the periphery of the retainer plate. The said protrusion (21) is associated with each window (19). In other words, the protrusion (21) is interrupted circumferentially between two windows. Each protrusion extending circumferentially is radially spaced from its spring window (19) towards the periphery of a retainer plate.

[040] As shown in figure 2A the said protrusion (21) is placed at the peripheral boundary. According to a second embodiment of the invention shown in figure 2B the protrusion is radially offset from the periphery of the retainer plate, a clearance of distance (Dc) separates the peripheral edge of the retainer plate and the protrusion. Any protrusion shown in figure 2A or 2B is radially outward to the window (19). Each window (19) is limited radially outward by a window eyelid (20) which is adapted to retain axially the spring (10) and the said protrusion (21) is located radially outward to the window eyelid (20).

[041] The said retainer plate is formed in a steel sheet, and protrusions (21) are formed directly in the steel sheet, for example by stamping. In the two retainer plates as shown in figure 1, the window openings (19) of each retainer plate receiving a damper spring (10) (14) and the two retainer plates being rigidly connected to each other with at least one connection element 7 which also acts as a stopper. The two retainer plates have the same axis of rotation. The said connection element or stopper is riveted with the retainer plates using the stopper slot (22) which are located at an equal radial length from the center of the retainer plate. At least a part of the connection slots (22) and the at least one protrusion (21) are located at the same radial distance of the axis of rotation. Consequently, the protrusion cannot circumferentially all around the axis of rotation (360°).

[042] In the damper assembly the drive plate is the vital part to transfer the torque from the retainer plate to the gearbox input shaft. As shown in figure 1 the drive plate (5) is located between the two retainer plates (4) (15) and contains openings (17) to house the damping spring (10) (14). The drive plate and central hub are coupled with the gearbox via a gearbox input shaft for the torque transfer.

[043] A damping spring (10) (14) is tensioned axially to fit in the connection openings (17) (19) provided in the drive plate and the retainer plates. The said drive plate is being able to rotate in relation to two retainer plates according to the axis of rotation of the retainer plates when the damping springs are working.

[044] The working of the clutch as discussed above is linked to the move of pressure plate towards the friction disc (1) in order to tighten the friction plates (1a, 1b) between the pressure plate and the flywheel to transfer torque from the engine to the damping assembly.

[045] The cushion disc (3) which is riveted between the friction plates transfers torque from the friction disc to the retainer plate (4) damping assembly. A spring element (10) (14) is used to transfer torque from the retainer plate (4) (15) to the drive plate (5). The purpose of the spring is to damp the sudden spike of torque due to non-uniform engine torque. From the retainer plate the spring suppress all the spikes and delivers only the stable torque with the drive plate (5). During compression and expansion of the damping spring a stopper (7) placed either side of the spring opening (17) of the drive plate used to limit the movement of the drive plate. The drive plate transfers stable torque to the gearbox shaft using the central hub (13).

[046] In the spring compression action at high speed, a very high centrifugal force being evolved around the window of the retainer plate. Around the window (19) the peripheral region has a lesser metal part and the frequent centrifugal forces on the weaker section is capable of damaging the retainer plate.
In the present invention to give mechanical strength and stiffness to the weaker section a plurality of protrusion is embossed in the the retainer plate peripheral part, radially outward to the windows (19).

[047] Any protrusion towards the periphery of the retainer plate window is embossed to add mechanical strength and stiffness to withstand centrifugal force of the spring action.

[048] As shown in figure 2A, a plurality of protrusion (21A) at the peripheral boundary, opposing to the retainer plate window (19) is created to increase stiffness in the weaker part of the retainer plate. One protrusion is associated to one window. In figure 2A the front view (27) of the retainer plate showing protrusion (21A) with length (La). In figure 2A sectional rear view (29) of the retainer plate showing protrusion impression groove (Ga), height of the protrusion (Ha) and width of the protrusion (Wa).

[049] As shown in figure 2B, a plurality of protrusion (21B) is created between the periphery and the window openings (19) to increase stiffness in the weaker part of the retainer plate. In figure 2B the front view (30) of the retainer plate showing protrusion (21B) with length (Lb). In figure 2B sectional rear view (32) of the retainer plate showing protrusion impression groove (Gb), a boundary clearance (Db), height of the protrusion (Hb) and width of the protrusion (Wb).