WO2022194427A1

WO2022194427A1 - Clutch system with wear indicator

Info

Publication number: WO2022194427A1
Application number: PCT/EP2022/025106
Authority: WO
Inventors: Sunny R. PAWAR; Shivam Sharma; Soma NAGARAJU; Saravana Kumar; Deepti Gupta
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2021-03-16
Filing date: 2022-03-16
Publication date: 2022-09-22
Anticipated expiration: 2023-09-16

Abstract

A dry friction clutch assembly that includes a cover assembly. A friction disc is disposed in the cover assembly. A pressure plate is disposed in the cover assembly. The pressure plate is movably engaged and disengaged with the friction disc. A wear indicator assembly is disposed in a cavity of the cover assembly. The wear indicator assembly includes a connecting link coupled to the pressure plate. The wear indicator assembly includes an indicia portion connected to the connecting link, the indicia portion moveable in response to a position of the pressure plate. A variable amount of the indicia portion is viewed in a dust cover based upon movement of the indicia portion providing a visual indication of a wear state of the friction disc.

Description

CLUTCH SYSTEM WITH WEAR INDICATOR

FIELD OF THE INVENTION [0001] The invention relates to a friction clutch.

BACKGROUND OF THE INVENTION

[0002] Dry friction clutches may be utilized for selective engagement of an engine with an input shaft of a transmission. Generally, dry clutches have a cover that is spaced from and connected with an engine flywheel. Inside the cover is a pressure plate that is connected to the cover and is axially moveable towards the flywheel. Positioned between pressure plate and flywheel is a friction disc. The friction disc is connected with an input shaft of a transmission. As the friction lining of the friction disc wears, it would be desirable to have a visual indication of the amount of wear as the friction disc cannot be seen when assembled. There is therefore a need for a visual indication letting a driver know what the wear condition of the friction disk to service the clutch as needed.

SUMMARY OF THE INVENTION

[0003] In one aspect, there is disclosed a dry friction clutch assembly that includes a cover assembly. A friction disc is disposed in the cover assembly. A pressure plate is disposed in the cover assembly. The pressure plate is movably engaged and disengaged with the friction disc. A wear indicator assembly is disposed in a cavity of the cover assembly. The wear indicator assembly includes a connecting link coupled to the pressure plate. The wear indicator assembly includes an indicia portion connected to the connecting link, the indicia portion moveable in response to a position of the pressure plate. A variable amount of the indicia portion is viewed in a dust cover based upon movement of the indicia portion providing a visual indication of a wear state of the friction disc.

[0004] In another aspect, there is disclosed a dry friction clutch assembly that includes a cover assembly. A friction disc is disposed in the cover assembly. A pressure plate is disposed in the cover assembly. The pressure plate is movably engaged and disengaged with the friction disc. A wear indicator assembly is disposed in a cavity of the cover assembly. The wear indicator assembly including a connecting rod having a ball joint positioned in a socket formed in the pressure plate. The wear indicator assembly including an indicating lever connected to the connecting link, the indicating lever including a pivot portion and a body portion. The body portion includes a pivot hole and wherein the body portion includes an arcuate shape having indicia formed thereon, the indicia portion moveable in response to a position of the pressure plate. A variable amount of the indicia portion is viewed in a dust cover based upon movement of the indicia portion providing a visual indication of a wear state of the friction disc.

[0005] In a further aspect, there is disclosed a dry friction clutch assembly that includes a cover assembly. A friction disc is disposed in the cover assembly. A pressure plate is disposed in the cover assembly. The pressure plate is movably engaged and disengaged with the friction disc. A wear indicator assembly is disposed in a cavity of the cover assembly. The wear indicator assembly includes a first link coupled to the pressure plate. The first link is attached to a telescopic cylindrical element. The wear indicator assembly includes a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link. A plate is attached to the housing behind the telescopic cylindrical element. The telescopic cylindrical element initially fully covers the plate indicating a no-wear condition and wherein as the friction plate wears, the first link causes the telescopic cylindrical element to retract, exposing the plate indicating the wear state of the friction disc.

[0006] In a further aspect, there is disclosed a dry friction clutch assembly that includes a cover assembly. A friction disc is disposed in the cover assembly. A pressure plate is disposed in the cover assembly. The pressure plate is movably engaged and disengaged with the friction disc. A wear indicator assembly is disposed in a cavity of the cover assembly. The wear indicator assembly including a first link coupled to the pressure plate. The first link is attached to a housing. The wear indicator assembly includes a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link. The first link includes a flat surface and a curved surface. The flat surface of the first link initially fully covers the dust cover indicating a no-wear condition and wherein as the friction plate wears, the first link causes the curved surface of the first link to move in the dust cover view indicating a wear state of the friction disc.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a partial cut away section of a friction clutch assembly including a wear indicator assembly;

[0008] Figure 2 is an exploded perspective view of a wear indicator assembly;

[0009] Figure 3 is a partial sectional view of a portion of a friction clutch and wear indicator assembly;

[0010] Figure 4 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a no wear condition;

[0011] Figure 5 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a worn condition; [0012] Figure 6 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a no wear condition;

[0013] Figure 7 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a 1 mm wear condition;

[0014] Figure 8 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a 2 mm wear condition;

[0015] Figure 9 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a 3 mm wear condition;

[0016] Figure 10 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a 4 mm wear condition;

[0017] Figure 11 is a partial sectional view of a portion of a friction clutch and wear indicator assembly in a 5 mm wear condition;

[0018] Figure 12 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a no wear condition;

[0019] Figure 13 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a half way wear condition;

[0020] Figure 14 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a worn condition;

[0021] Figure 15 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a no wear condition;

[0022] Figure 16 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a half way wear condition; [0023] Figure 17 is a partial sectional view of a portion of a friction clutch and alternative wear indicator assembly in a worn condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0024] Referring to FIGS. 1-11, there is shown a dry friction clutch assembly 20. The dry friction clutch assembly 20 includes a cover assembly 22 that is torsionally coupled to a flywheel 23 of an engine. The cover assembly 22 is torsionally coupled to a pressure plate 24.

[0025] The cover assembly 22 includes a diaphragm spring 30 positioned therein. The diaphragm spring 30 is a disc-shaped Belleville spring having a continuous solid outer rim portion. Projecting radially inward from the rim is a series of diaphragm spring fingers. Holding the diaphragm spring 30 in position is a fulcrum ring 34. The ring 34 applies an upward force to load the diaphragm spring 30 and maintain it in position. The rim of the diaphragm spring 30 pushes downward on the pressure plate 24.

[0026] The pressure plate 24 has a flat annular surface 42 for engagement with a friction disc 44. The pressure plate 24 is axially movable with respect to the housing 28. The clamping movement of the pressure plate 24 is induced by the clamping load of the diaphragm spring 30 causing the pressure plate 24 to engage with the friction disc 44. The friction disc 44 is engaged with the flywheel 23 to torsionally connect the engine with the input shaft of the transmission. In the normal state of operation, the clutch assembly 20 engages the transmission with the engine unless the clutch is released.

[0027] To torsionally disconnect the transmission from the engine, a shift fork’s release bearing (not shown) contacts the fingers causing the diaphragm spring 30 to elastically deform causing the rim to pivot away from the pressure plate 24 allowing the pressure plate 24 to disengage from the friction disc 44.

[0028] As the dry friction clutch assembly 20 is repeatedly actuated there is wear of the friction disc 44. A wear indicator assembly 46 is attached to the dry friction clutch assembly 20 to provide a visual indication of the amount of wear. The wear indicator assembly 46 is disposed in a cavity 48 defined in the cover assembly 22.

[0029] Referring to Figures 1 and 2, the wear indicator 46 assembly includes a socket 50 attached to the pressure plate 24 by a socket bolt 52. An O-ring 54 may be positioned within the socket 50. A connecting rod 56 having a ball joint 58 is press fit and positioned in the socket 50. The connecting rod 56 extends to a connection portion 60 that includes a connection cavity 62 that receives a connecting rod bolt 64 that couples the connection rod 56 to an indicating lever 66. In one aspect, the connecting rod 56 may be a connecting link that couples the pressure plate 24 to an indicia portion, as will be discussed in more detail below.

[0030] The connecting rod bolt 64 is attached to a bush bearing 68 that is attached to the indicating lever 66. In one aspect, the indicating lever may be an indicia portion, as will be discussed in more detail below.

[0031] The indicating lever 66 includes a pivot portion 70 and body portion 72. The pivot portion 70 includes a pivot hole 74. The body portion 72 includes an arcuate shape having indicia 76 formed thereon. The indicia 76 may include different colors such as green and red which indicates the wear condition of the friction disc 44, as will be described in more detail below. [0032] An L-bracket 78 includes a pivot end 80 having an attachment cylinder 82 that is disposed in the pivot hole 74. The L-shaped bracket 78 is attached to the cover assembly 22. A dust cover 84 overlays an opening of the cavity 48 formed in the cover assembly 22 allowing a view of the indicating lever 66, as will be discussed in more detail below.

[0033] Referring to Figure 3, there is shown the wear indicator assembly 46 including a pivot angle (a) of the indicating lever 66, an articulation angle (Q) of the connecting rod 56 and a linear displacement (x) of the pressure plate 24 due to wear of the friction disc 44. As the pressure plate moves 24 in the direction (x) the indicating lever 66 translates about the attachment cylinder 82 of the L-shaped bracket 78 that defines the pivot. Translation of the indicating lever 66 results in a change of the angle (a) and a different indicia 76 being seen through the dust cover 84.

[0034] Referring to Figures 3-4, the wear indicator 46 assembly is shown in an unworn and worn state respectively. In the unworn condition of Figure 4, the angle (a) is zero and the indicia 76 through the dust cover 84 is fully green and indicates no wear. In the worn condition of Figure 5, the angle (a) is greater than zero at around 70 degrees and the indicia 76 through the dust cover 84 is fully red and indicates wear.

[0035] As the indicating lever 66 translates due to varying wear of the friction disc 44, a variable amount of the no wear and wear indicia 76 is seen. Referring to Figures 6-11 there is shown the translation angle and wear displacement at various amounts as shown in the Table. The translation of the indicating lever 66 provides a visual indication of a wear state of the friction disc 44 which cannot be seen and allows for proper servicing of the dry clutch assembly 20.

[0036] Referring to Figures 12-14 there is shown an alternative wear indicator assembly 146. The wear indicator assembly 146 includes a linkage assembly 148. The linkage assembly 148 includes a Scott Russel mechanism. The Scott Russel mechanism gives a linear motion by using a linkage form with three portions of the links, all equal in length and a rolling or sliding connection used to form right angle change of motion, linear to linear. [0037] A first link 150 of the Scott Russel mechanism is connected to the friction plate 24 by a coupling 152 and the other end 154 of the first link 150 is connected to a telescopic green colored cylindrical element 156. The second link 158 is coupled at one end 160 to the midpoint of the first link 150 and to a housing 162 of the cylinder at the other end 164 of the second link 158. This arrangement defines three equal length link portions 166.

[0038] Behind the cylinder 156, there is attached a red-colored plate 168. The telescopic cylinder 156 initially fully covers the red colored plate 168, indicating no- wear condition. As the friction plate 44 wears, the Scott Russel mechanism causes the telescopic green colored cylinder 156 to retract, thus exposing the red colored plate 168. The extent of red colored plate 168 exposure indicates clutch wear.

[0039] As the pressure plate 24 moves in the direction (x) the coupling 152 pulls the first linkage 150 and moves the telescopic cylinder 156. Movement of the telescopic cylinder 156 results in a different indicia 76 being seen through the dust cover.

[0040] As the telescopic cylinder 156 moves, a variable amount of the no wear and wear indicia 76 is seen. Referring to Figures 12-14 there is shown the wear indicator assembly 146 in an unworn, half worn and fully worn state. The movement of the telescopic cylinder 156 provides a visual indication of wear of the friction disc 44 which cannot be seen and allows for proper servicing of the dry clutch assembly 20.

[0041] Alternatively, the embodiment of Figures 12-14 including the Scott Russel mechanism may include an indicia portion as described above for the embodiment of Figures 1-11. Referring to Figures 15-16, in the depicted embodiment a first link 150 of the Scott Russel mechanism is connected to the friction plate 24 by a coupling 152 and the other end 154 of the first link 150 is connected to a housing. The second link 158 is coupled at one end 160 to the midpoint of the first link 150 and to a housing 162 of the cylinder at the other end 164 of the second link 158. This arrangement defines three equal length link portions 166.

[0042] The flat surface 163 of the first link 150 initially fully covers the viewing zone of the user, indicating no-wear condition. As the friction plate 24 wears, the Scott Russel mechanism causes the curved surface 165 of the first link 150 to come in the viewing zone, thus exposing red color to the user. The extent of red color in the viewing zone indicates clutch wear.

[0043] As the pressure plate 24 moves in upward direction, the coupling 152 pulls the first linkage 150 and brings the curved surface 165 and red color in the viewing zone, seen through the dust cover.

[0044] The mechanism can show unworn Figure 15, half worn Figure 16 and fully worn state Figure 17 of the clutch which allows for proper servicing of the dry clutch assembly.

Claims

1. A dry friction clutch assembly comprising: a cover assembly; a friction disc disposed in the cover assembly; a pressure plate disposed in the cover assembly, the pressure plate movably engaged and disengaged with the friction disc; a wear indicator assembly disposed in a cavity of the cover assembly, the wear indicator assembly including a connecting link coupled to the pressure plate, the wear indicator assembly including an indicia portion connected to the connecting link, the indicia portion moveable in response to a position of the pressure plate; wherein a variable amount of the indicia portion is viewed in a dust cover based upon movement of the indicia portion providing a visual indication of a wear state of the friction disc.

2. The dry friction clutch assembly of claim 1 wherein the connecting link includes a connecting rod having a ball joint positioned in a socket formed in the pressure plate.

3. The dry friction clutch assembly of claim 2 wherein the connecting rod extends to a connection portion that includes a connection cavity that receives a connecting rod bolt that couples the connection rod to an indicating lever.

4. The dry friction clutch assembly of claim 3 wherein the connecting rod bolt is attached to a bush bearing that is attached to the indicating lever, the indicating lever including a pivot portion and a body portion.

5. The dry friction clutch assembly of claim 4 wherein the body portion includes a pivot hole and wherein the body portion includes an arcuate shape having indicia formed thereon.

6. The dry friction clutch assembly of claim 5 further including an L-bracket having a pivot end having an attachment cylinder that is disposed in the pivot hole, the L-shaped bracket attached to the cover assembly.

7. The dry friction clutch assembly of claim 6 including a pivot angle (a) of the indicating lever, an articulation angle (Q) of the connecting rod and a linear displacement (x) of the pressure plate 24 due to wear of the friction disc 44 wherein as the pressure plate moves in the direction (x) the indicating lever translates about the attachment cylinder of the L-shaped bracket that defines the pivot and wherein translation of the indicating lever results in a change of the angle (a) and a different indicia being seen through the dust cover.

8. The dry friction clutch assembly of claim 1 wherein the connecting link includes a first link connected to the friction plate by a coupling.

9. The dry friction clutch assembly of claim 8 wherein another end of the first link is coupled to a telescopic cylindrical element.

10. The dry friction clutch assembly of claim 9 further including a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link.

11. The dry friction clutch assembly of claim 10 including a plate attached behind the telescopic cylindrical element.

12. The dry friction clutch assembly of claim 11 wherein the telescopic cylindrical element initially fully covers the plate indicating a no-wear condition and wherein as the friction plate wears, the first link causes the telescopic cylindrical element to retract, exposing the plate indicating the wear state of the friction disc.

13. The dry friction clutch assembly of claim 1 wherein the connecting link includes a first link connected to the friction plate by a coupling.

14. The dry friction clutch assembly of claim 13 wherein another end of the first link is coupled to a housing.

15. The dry friction clutch assembly of claim 14 further including a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link.

16. The dry friction clutch assembly of claim 13 wherein the first link includes a flat surface and a curved surface.

17. The dry friction clutch assembly of claim 16 wherein the flat surface of the first link initially fully covers the dust cover indicating a no-wear condition and wherein as the friction plate wears, the first link causes the curved surface of the first link to move in the dust cover view indicating a wear state of the friction disc.

18. A dry friction clutch assembly comprising: a cover assembly; a friction disc disposed in the cover assembly; a pressure plate disposed in the cover assembly, the pressure plate movably engaged and disengaged with the friction disc; a wear indicator assembly disposed in a cavity of the cover assembly, the wear indicator assembly including a connecting rod having a ball joint positioned in a socket formed in the pressure plate, the wear indicator assembly including an indicating lever connected to the connecting link, the indicating lever including a pivot portion and a body portion wherein the body portion includes a pivot hole and wherein the body portion includes an arcuate shape having indicia formed thereon, the indicia portion moveable in response to a position of the pressure plate; wherein a variable amount of the indicia portion is viewed in a dust cover based upon movement of the indicia portion providing a visual indication of a wear state of the friction disc.

19. A dry friction clutch assembly comprising: a cover assembly; a friction disc disposed in the cover assembly; a pressure plate disposed in the cover assembly, the pressure plate movably engaged and disengaged with the friction disc; a wear indicator assembly disposed in a cavity of the cover assembly, the wear indicator assembly including first link coupled to the pressure plate, the first link attached to a telescopic cylindrical element, the wear indicator assembly including a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link; a plate attached to the housing behind the telescopic cylindrical element; wherein the telescopic cylindrical element initially fully covers the plate indicating a no-wear condition and wherein as the friction plate wears, the first link causes the telescopic cylindrical element to retract, exposing the plate indicating the wear state of the friction disc.

20. A dry friction clutch assembly comprising: a cover assembly; a friction disc disposed in the cover assembly; a pressure plate disposed in the cover assembly, the pressure plate movably engaged and disengaged with the friction disc; a wear indicator assembly disposed in a cavity of the cover assembly, the wear indicator assembly including first link coupled to the pressure plate, the first link attached to a housing, the wear indicator assembly including a second link that is coupled at one end to a midpoint of the first link and to a housing at another end of the second link; the first link includes a flat surface and a curved surface; wherein the flat surface of the first link initially fully covers the dust cover indicating a no-wear condition and wherein as the friction plate wears, the first link causes the curved surface of the first link to move in the dust cover view indicating a wear state of the friction disc.