Diaphragm spring

Abstract

To provide a diaphragm spring capable of suppressing movement of a release bearing when centrifugal force is applied, and capable of suppressing deterioration of operation feeling of a clutch pedal.SOLUTION: A plurality of feet extending radially inward from an outer peripheral part includes a first foot whose inner peripheral part is more likely to be displaced toward a release bearing due to centrifugal force, and a second foot whose inner peripheral part is displaced toward the release bearing by less centrifugal force than the first foot. In addition, a root portion of the first foot adjacent to the outer peripheral part is shorter in circumferential length than a root portion of the second foot adjacent to the outer peripheral part, and has a bow-like shape that protrudes toward a clutch disc.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a diaphragm spring attached to a clutch cover. [Background technology]

[0002] A well-known diaphragm spring is attached to a clutch cover and includes an outer peripheral portion that biases a pressure plate toward a clutch disc, and a plurality of legs that extend radially inward from the outer peripheral portion and abut against the inner peripheral portion so that a release bearing can bias the pressure plate toward the clutch disc. Patent Document 1 discloses an example of such a clutch diaphragm spring. The legs of the diaphragm spring are shaped so that adjacent legs have different resonance points, preventing vibrations generated in one leg from being amplified and transmitted to the other legs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-35155 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, for example, during high rotation speeds, centrifugal force displaces the inner periphery of the diaphragm spring toward the release bearing, while displacing the clutch cover toward the clutch disc. In this case, the inner periphery of the diaphragm spring displaces toward the clutch disc due to the displacement of the clutch cover. If the displacement of the inner periphery of the diaphragm spring toward the clutch disc due to the displacement of the clutch cover is greater than the displacement toward the release bearing, the inner periphery of the diaphragm spring is displaced toward the clutch disc. Furthermore, the release bearing, which abuts against the inner periphery of the diaphragm spring, is moved toward the clutch disc. A concentric slave cylinder integral with the release bearing is sometimes used as an actuator to move the release bearing so that the release bearing biases the inner periphery of the diaphragm spring toward the clutch disc. In a concentric slave cylinder, the piston is divided into a release bearing side and an oil chamber side to isolate vibrations. Therefore, as described above, when centrifugal force is applied, the inner periphery of the diaphragm spring is displaced, causing the release bearing to move toward the clutch disc, resulting in rattle between the divided pistons.When rattle occurs between the pistons in the concentric slave cylinder, rattle (play) in the clutch pedal increases, which can worsen the feel of the clutch pedal.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide a diaphragm spring that can suppress movement of the release bearing when centrifugal force is applied, and can suppress deterioration of the clutch pedal operation feel. [Means for solving the problem]

[0006] The gist of the first invention is a diaphragm spring that includes: (a) an outer peripheral portion that is attached to a clutch cover and that urges a pressure plate toward the clutch disc; and a plurality of feet that extend radially inward from the outer peripheral portion and abut against the inner peripheral portion so that a release bearing can be urged toward the clutch disc; (b) the plurality of feet include a first foot that has an inner peripheral portion that is easily displaced toward the release bearing by centrifugal force, and a second foot that has a smaller amount of displacement of the inner peripheral portion toward the release bearing by centrifugal force than the first foot; and (c) a base portion of the first foot that is adjacent to the outer peripheral portion has a shorter circumferential length and a shape that protrudes in an arch toward the clutch disc than a base portion of the second foot that is adjacent to the outer peripheral portion. [Effects of the Invention]

[0007] According to the first aspect of the present invention, the multiple feet extending radially inward from the outer periphery include a first foot, whose inner periphery is easily displaced toward the release bearing due to centrifugal force, and a second foot, whose inner periphery is displaced toward the release bearing by less centrifugal force than the first foot. Additionally, the root portion of the first foot adjacent to the outer periphery has a shorter circumferential length and a bow-like shape protruding toward the clutch disc compared to the root portion of the second foot adjacent to the outer periphery. As a result, when centrifugal force is applied, the inner periphery of the second foot is easily displaced toward the clutch disc and thus separates from the release bearing. On the other hand, when centrifugal force is applied, the inner periphery of the first foot is easily displaced toward the release bearing and therefore always abuts against the release bearing. Therefore, even when centrifugal force is applied, rattle is less likely to occur between the pistons in the concentric slave cylinder. When centrifugal force is applied and the release bearing is moved toward the clutch disc as the clutch pedal is operated, the first foot moves first, and then the release bearing abuts against the inner periphery of the second foot. The first and second foot are then moved together by the release bearing, ensuring proper operation of the friction clutch. Therefore, the diaphragm spring can suppress movement of the release bearing when centrifugal force is applied, preventing a deterioration in the clutch pedal operation feel. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a friction clutch equipped with a diaphragm spring to which the present invention is applied. [Figure 2] FIG. 4 is a diagram illustrating the shape of a diaphragm spring. [Figure 3] 4A and 4B are diagrams illustrating an example of the operation of a friction clutch. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] Fig. 1 is a diagram illustrating the schematic configuration of a friction clutch 30 equipped with a diaphragm spring 40 to which the present invention is applied. Fig. 1(a) is a cross-sectional view showing the schematic configuration of a part of a vehicle power transmission device 10 in which the friction clutch 30 is provided, and a vehicle clutch device 50 that actuates the friction clutch 30. Fig. 1(b) is a cross-sectional view showing an enlarged view of the friction clutch 30 and its surroundings.

[0011] 1, a vehicle power transmission device 10 includes a friction clutch 30 and a transmission 14 that transmits power from an engine 12, which serves as a power source for the vehicle, to drive wheels (not shown) via the friction clutch 30. The friction clutch 30 is a dry single-plate disc clutch provided in a power transmission path between the engine 12 and the transmission 14, and functions as a friction coupling that transmits power by friction. The friction clutch 30 is provided at one end of an input shaft 20 of the transmission 14 within a clutch housing 18 that is integrally connected between the engine 12 and a transmission housing 16 that accommodates the transmission 14 in a liquid-tight manner.

[0012] The friction clutch 30 includes a disk-shaped flywheel 32, a disk-shaped clutch disc 34, a clutch cover 36 fixed to the flywheel 32, a circular plate-shaped pressure plate 38, and a circular plate-shaped diaphragm spring 40.

[0013] The flywheel 32 is fixed to the output end of the crankshaft 12c, which serves as an output rotating member of the engine 12, and is rotated integrally with the crankshaft 12c. The clutch disc 34 is located on the same axis C as the flywheel 32 and is rotatable relative to the flywheel 32. The inner periphery of the clutch disc 34 is spline-fitted to one end of the input shaft 20 so as to be relatively movable in the direction of the axis C but not relatively rotatable around the axis C. The clutch disc 34 has friction materials (facings, linings) fixed to both surfaces of its outer periphery, i.e., the surfaces facing the flywheel 32 and the pressure plate 38, respectively. The pressure plate 38 is relatively movable in the direction of the axis C within the clutch cover 36 and is disposed on the side of the clutch disc 34 opposite the flywheel 32 so as to be movable toward and away from the clutch disc 34. The flywheel 32, clutch disc 34, and pressure plate 38 are disposed adjacent to one another in this order in the direction of the axis C from the engine 12 side. The axis C is the axis of the input shaft 20 of the transmission 14 .

[0014] The diaphragm spring 40 is attached to the clutch cover 36 on the side of the pressure plate 38 opposite the clutch disc 34. The diaphragm spring 40 is sandwiched between an outer peripheral portion 80 (see FIG. 2) and an inner peripheral portion 82i (see FIG. 2) by a pair of annular fulcrum members 42, 44 disposed on the clutch cover 36. When the inner peripheral portion 82i of the diaphragm spring 40 is pressed toward the clutch disc 34 in the direction of the axis C, the outer peripheral portion 80 rotates in a direction away from the pressure plate 38 while being supported by the fulcrum members 42, 44. Furthermore, when the pressure of the inner peripheral portion 82i toward the clutch disc 34 is released, the elastic return force of the diaphragm spring 40 returns the outer peripheral portion 80 to a state in which it urges the pressure plate 38 toward the clutch disc 34.

[0015] In the friction clutch 30 configured as described above, when no external force acts on the inner peripheral portion 82i of the diaphragm spring 40, the pressure plate 38 is pressed toward the clutch disc 34 by the outer peripheral portion 80 of the diaphragm spring 40. As a result, the clutch disc 34 is sandwiched between the pressure plate 38 and the flywheel 32, and the friction clutch 30 is in a fully engaged state in which the clutch disc 34 is frictionally engaged with the flywheel 32 and the pressure plate 38. When the friction clutch 30 is in the fully engaged state, power transmission between the flywheel 32 and the clutch disc 34, i.e., between the crankshaft 12c and the input shaft 20, is in a power transmittable state in which power transmission is possible.

[0016] Furthermore, in the friction clutch 30, when the inner peripheral portion 82i of the diaphragm spring 40 is operated toward the clutch disc 34 in the direction of the axis C, the pressing force of the pressure plate 38 toward the clutch disc 34 is changed according to the operating force, i.e., the clutch operating force. When the pressing force is completely released, the friction clutch 30 enters a fully released state in which the frictional engagement between the clutch disc 34 and the flywheel 32 and pressure plate 38 is released. When the friction clutch 30 enters the fully released state, the power transmission state between the flywheel 32 and the clutch disc 34 enters a power transmission disabled state in which power transmission is interrupted.

[0017] The vehicle clutch device 50 includes a clutch pedal 52, a clutch master cylinder 54, a reservoir tank 56, a connecting pipe 58, and a concentric slave cylinder 60 (=CSC 60).

[0018] The clutch pedal 52 is an operating member that is operated (for example, depressed) by the driver to switch the operating state of the friction clutch 30. When the driver depresses the clutch pedal 52, the friction clutch 30 is opened (i.e., placed in a fully released state). When the driver releases the depression of the clutch pedal 52, the friction clutch 30 is closed (i.e., placed in a fully engaged state).

[0019] The clutch master cylinder 54 converts the depression force of the clutch pedal 52 into hydraulic pressure, and generates clutch hydraulic pressure according to the amount of depression (operation amount) of the clutch pedal 52 in response to the operation, i.e., depression, of the clutch pedal 52. The reservoir tank 56 is a container for storing excess hydraulic oil. The connecting pipe 58 is an oil passage, such as a flexible hose, that connects the clutch master cylinder 54 and the CSC 60 and through which the hydraulic oil flows.

[0020] The CSC 60 is an actuator that receives clutch operating hydraulic pressure output from the clutch master cylinder 54 and operates (engages and disengages) the friction clutch 30. The CSC 60 includes a cylindrical inner sleeve 62 and an outer sleeve 64 that are annularly provided on the outer peripheral surface of the input shaft 20 that penetrates the partition wall 22, which is a non-rotating member, inside the clutch housing 18 and are fixed to the partition wall 22. The inner sleeve 62 and the outer sleeve 64 are each positioned on the axis C, and the outer sleeve 64 is positioned on the outer peripheral side of the inner sleeve 62.

[0021] An annular space is formed in the gap between the outer peripheral wall of the inner sleeve 62 and the inner peripheral wall of the outer sleeve 64, and this space defines a pressure chamber 66. The pressure chamber 66 is an oil-tight space formed to receive the clutch operating oil pressure output from the clutch master cylinder 54. The pressure chamber 66 is surrounded by the inner sleeve 62, the outer sleeve 64, and a sliding cup 68 provided in the CSC 60. The sliding cup 68 is fitted between the outer peripheral wall of the inner sleeve 62 and the inner peripheral wall of the outer sleeve 64 so as to be able to slide, and also functions as a sealing member.

[0022] The CSC 60 further includes an annular output piston 70 disposed adjacent to the sliding cup 68 on the side of the sliding cup 68 opposite the pressure chamber 66. The output piston 70 is a piston fitted in a gap between the outer peripheral wall of the inner sleeve 62 and the inner peripheral wall of the outer sleeve 64 so as to be slidable in the direction of the axis C. The output piston 70 receives clutch operating hydraulic pressure supplied to the pressure chamber 66 and is moved in the direction of the axis C via the sliding cup 68, and transmits a clutch operating force to the friction clutch 30.

[0023] Here, the output piston 70 is composed of two divided members, a first piston 72 and a second piston 74, each having an annular shape, which are configured to be able to separate from each other in the direction of the axis C (see also FIG. 2(d)). That is, a small gap (backlash) can be formed between the first piston 72 and the second piston 74 in the output piston 70. The backlash formed between the first piston 72 and the second piston 74 in the output piston 70 absorbs vibrations from the engine 12. When the second piston 74 receives clutch operating oil pressure in the pressure chamber 66 and is moved toward the friction clutch 30 via the sliding cup 68, the first piston 72 and the second piston 74 come into contact with each other, and the thrust is transmitted to the first piston 72, which is also moved toward the friction clutch 30.

[0024] The vehicle clutch device 50 further includes a release bearing 76 and a spring 78. The release bearing 76 is provided between the output piston 70 and the diaphragm spring 40 and is a member that allows the output piston 70 and the diaphragm spring 40 to transmit forces in the direction of the axis C while allowing relative rotation between them. The release bearing 76 transmits the clutch operating force from the output piston 70 to the diaphragm spring 40 and the spring reaction force from the diaphragm spring 40 to the output piston 70. The springs 78 are two springs that are interposed between the outer sleeve 64 and the release bearing 76. The release bearing 76 is constantly biased toward the diaphragm spring 40 by the spring 78 and is constantly in contact with the inner peripheral portion 82i of the diaphragm spring 40.

[0025] The output piston 70 is configured to move from a position corresponding to the fully engaged state of the friction clutch 30 to a position corresponding to the fully released state of the friction clutch 30 in accordance with the clutch hydraulic pressure supplied to the pressure chamber 66. The position corresponding to the fully engaged state of the friction clutch 30 is the position where the volume of the pressure chamber 66 is smallest, and the position corresponding to the fully released state of the friction clutch 30 is the position where the volume of the pressure chamber 66 is largest. The greater the clutch hydraulic pressure in the pressure chamber 66, the greater the clutch operating force transmitted from the output piston 70 to the diaphragm spring 40. In the CSC 60, the output piston 70 is moved in accordance with the clutch hydraulic pressure supplied to the pressure chamber 66, and the clutch operating force is transmitted to the inner peripheral portion 82i of the diaphragm spring 40.

[0026] Fig. 2 is a diagram illustrating the shape of the diaphragm spring 40. Fig. 2(a) is a plan view of the diaphragm spring 40 as viewed from the direction of the axis C. Fig. 2(b) is a cross-sectional view taken along line AA in Fig. 2(a). Fig. 2(c) is a cross-sectional view taken along line BB in Fig. 2(a). Fig. 2(d) is a diagram in which, for convenience, two different types of levers of the diaphragm spring 40 are superimposed on the cross-sectional view of Fig. 1(b).

[0027] 2, the diaphragm spring 40 has an outer peripheral portion 80 and a plurality of foot portions 82. The outer peripheral portion 80 is a portion that urges the pressure plate 38 toward the clutch disc 34. The foot portions 82 are portions that extend radially inward from the outer peripheral portion 80. The foot portions 82 are portions that abut against an inner peripheral portion 82i so that the release bearing 76 can be urged toward the clutch disc 34.

[0028] The multiple feet 82 include a holding lever 84 and an operating lever 86. The holding lever 84 has a relatively low rigidity structure and is a first foot in which the inner periphery 84i is easily displaced toward the release bearing 76 due to centrifugal force. The operating lever 86 has a relatively high rigidity structure and is a second foot in which the inner periphery 86i is less displaced toward the release bearing 76 due to centrifugal force than the holding lever 84.

[0029] As shown in the circled area D, the base portion 84b of the holding lever 84 adjacent to the outer periphery 80 is shorter in circumferential length than the base portion 86b of the operating lever 86 adjacent to the outer periphery 80 and has a shape that protrudes in an arch shape toward the clutch disc 34. The base portion 84b of the holding lever 84 has a shape that is easily deformed by centrifugal force. As a result, the holding lever 84 is structured to be more susceptible to the influence of centrifugal force than the operating lever 86.

[0030] Figure 3 is a diagram illustrating an example of the operation of the friction clutch 30. Figure 3(a) is a diagram illustrating an example of the movement of the diaphragm spring 40 when clutch actuation oil pressure is not supplied to the pressure chamber 66 of the CSC 60 and the clutch cover 36 is in a high rotation state. Figure 3(b) is a diagram illustrating an example of the movement of the diaphragm spring 40 when clutch actuation oil pressure is supplied to the pressure chamber 66 of the CSC 60. Figure 3(c) is a diagram illustrating the relationship between the pedal depression force and pedal stroke when the clutch pedal 52 is depressed. Figure 3(d) is a diagram illustrating the relationship between the lever positions of the holding lever 84 and the operating lever 86 and the position of the release bearing 76 when the clutch cover 36 is in a high rotation state.

[0031] 3, when the clutch cover 36 is in a high rotation speed state, centrifugal force tends to displace the inner periphery 82i of the foot 82 toward the release bearing 76, while the clutch cover 36 tends to displace toward the clutch disc 34. Furthermore, the inner periphery 82i of the foot 82 is displaced toward the clutch disc 34 as the clutch cover 36 is displaced. The inner periphery 86i of the highly rigid operating lever 86 is displaced toward the clutch disc 34 more than toward the release bearing 76 as the clutch cover 36 is displaced (see FIG. 3(a)). In this case, in a comparative example that does not have a low-rigidity holding lever 84, the release bearing 76 is moved toward the clutch disc 34 while abutting against the inner periphery 86i of the operating lever 86. As a result, play occurs between the divided first piston 72 and second piston 74 in the CSC 60, increasing the play (play) in the clutch pedal 52 (see FIG. 3(c)). This may result in a deterioration in the feel of the clutch pedal 52.

[0032] This embodiment has a low-rigidity holding lever 84. The amount of displacement of the inner peripheral portion 84i of the low-rigidity holding lever 84 toward the release bearing 76 is set to be approximately equal to the amount of displacement toward the clutch disc 34 associated with displacement of the clutch cover 36, so that the inner peripheral portion 84i is always in contact with the release bearing 76 (see FIG. 3(a)). This suppresses movement of the release bearing 76 toward the clutch disc 34, and makes it less likely that rattle will occur between the divided first piston 72 and second piston 74 in the CSC 60.

[0033] When clutch operating oil pressure is supplied to the pressure chamber 66 of the CSC 60 while the clutch cover 36 is in a high rotation speed state, the release bearing 76 moves toward the clutch disc 34, and first the inner peripheral portion 84i of the holding lever 84 is displaced toward the clutch disc 34. After that, the holding lever 84 and the operating lever 86 are moved integrally by the release bearing 76, and the function of the friction clutch 30, that is, transmission and interruption of power transmission, is performed (see FIGS. 3(b) and 3(d)).

[0034] The inner peripheral portion 84i of the holding lever 84 is likely to displace toward the release bearing 76 when the clutch cover 36 is rotating at high speeds, which causes a relatively large centrifugal force, and therefore the amount of displacement of the release bearing 76 toward the clutch disc 34 can be reduced. The holding lever 84 has the function of holding the release bearing 76. The operating lever 86, together with the holding lever 84, has the function of causing the friction clutch 30 to perform the functions of power interruption and power transmission.

[0035] As described above, according to this embodiment, even when centrifugal force is applied, rattle is less likely to occur between the first piston 72 and the second piston 74 inside the CSC 60. Therefore, movement of the release bearing 76 when centrifugal force is applied is suppressed, and deterioration in the operation feel of the clutch pedal 52 can be suppressed.

[0036] The above describes in detail an embodiment of the present invention based on the drawings, but what has been described above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0037] 34: Clutch disc 36: Clutch cover 38: Pressure plate 40: Diaphragm spring 76: Release bearing 80: Outer periphery 82: Foot 82i: Inner periphery 84: Holding lever (first foot) 84b: Base 84i: Inner periphery 86: Operating lever (second foot) 86b: Base 86i: Inner periphery

Claims

[Claim 1] A diaphragm spring is provided which is attached to a clutch cover and includes an outer peripheral portion which urges a pressure plate toward a clutch disc, and a plurality of legs which extend radially inward from the outer peripheral portion and abut against an inner peripheral portion so that a release bearing can urge the pressure plate toward the clutch disc, the plurality of feet include a first foot, the inner circumferential portion of which is easily displaced toward the release bearing by centrifugal force, and a second foot, the inner circumferential portion of which is displaced toward the release bearing by centrifugal force by a smaller amount than the first foot, A diaphragm spring characterized in that a base portion of the first foot adjacent to the outer periphery has a shorter circumferential length than a base portion of the second foot adjacent to the outer periphery and has a shape that protrudes in an arch shape toward the clutch disc.

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