Hysteresis torque generation mechanism and power transmission device

Abstract

This invention discloses a hysteresis torque generating mechanism and a power transmission device. It stabilizes the initial hysteresis torque based on a friction component. The hysteresis torque generating mechanism includes: a hub flange (21) having a sliding surface; and a friction member (41). The friction member (41) slides on the sliding surface of the opposing hub flange (21) to generate hysteresis torque. The friction member (41) has an initial contact portion (41b) and a main friction surface (41a). The initial contact portion (41b) protrudes towards the hub flange (21) and slides in contact with the sliding surface of the hub flange (21). After the initial contact portion (41b) wears, the main friction surface (41a) slides in contact with the sliding surface of the hub flange (21).

Description

Technical Field

[0001] The present invention relates to a hysteresis torque generating mechanism and a power transmission device having the hysteresis torque generating mechanism. Background Technology

[0002] In a vehicle's power transmission system, a damping device is installed to attenuate torsional vibrations. This damping device has a hysteresis torque generating mechanism for generating a hysteresis torque as a frictional resistance. For example, as shown in Patent Document 1, the hysteresis torque generating mechanism consists of a friction component (friction washer), a conical spring, etc. The friction component is positioned between an input-side rotating body and an output-side rotating body that can rotate relative to each other, with the input-side rotating body pressed against the output-side rotating body by the conical spring. Moreover, when the input-side rotating body and the output-side rotating body rotate relative to each other due to torsional vibrations, the friction component rotates integrally with either the input-side or output-side rotating body and comes into frictional contact with the other, thereby generating a hysteresis torque.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 9-242823 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] Friction components wear down their sliding surfaces during use, and after the sliding surfaces wear down to a certain extent, a stable hysteresis torque can be obtained.

[0008] However, in the initial stage of use, due to manufacturing errors, the shape of the friction sliding surface may deviate. Therefore, the contact surface with the opposite component is unstable, and the initial hysteresis torque is unstable.

[0009] The objective of this invention is to stabilize the initial hysteresis torque based on friction components.

[0010] Solutions for solving technical problems

[0011] (1) The hysteresis torque generating mechanism of the present invention comprises: a first rotating body having a sliding surface; and a second rotating body disposed opposite to the first rotating body, which slides on the sliding surface of the first rotating body to generate hysteresis torque, the second rotating body having an initial contact portion and a main friction surface. The initial contact portion is provided protruding toward the first rotating body and slides in contact with the sliding surface of the first rotating body. After the initial contact portion wears down, the main friction surface slides in contact with the sliding surface of the first rotating body.

[0012] Here, in the initial stage of use of the second rotating body, the initial contact portion slides into contact with the sliding surface of the first rotating body. That is, the initial contact portion is intentionally provided in the friction component, so that the desired hysteresis torque can be obtained in the initial stage. Moreover, after the initial contact portion wears down, the main friction surface, including the worn initial contact portion, slides into contact with the sliding surface of the first rotating body.

[0013] (2) Preferably, the first rotating body is a component that receives power and transmits the input power to a component on the output side. In addition, the second rotating body is a friction component that can rotate relative to the first rotating body.

[0014] (3) Preferably, the initial contact portion is formed in a ring shape.

[0015] (4) Preferably, the second rotating body has a body and a friction element. The friction element is fixed to the body and has an initial contact portion and a main friction surface on its surface.

[0016] (5) Preferably, the body is made of resin and the friction element is embedded in the body.

[0017] (6) The power transmission device of the present invention comprises: an input-side rotating body, an output-side rotating body, a plurality of elastic members, and a hysteresis torque generating mechanism. The output-side rotating body is configured to rotate relative to the input-side rotating body. The plurality of elastic members elastically connect the input-side rotating body and the output-side rotating body in the rotational direction. The hysteresis torque generating mechanism generates a hysteresis torque when the input-side rotating body and the output-side rotating body rotate relative to each other.

[0018] Furthermore, the hysteresis torque generating mechanism includes a friction component and a pressing component. The friction component is disposed axially between the input-side rotating body and the output-side rotating body. The pressing component presses the first side surface of the friction component against the side surface of the input-side rotating body or the output-side rotating body. Moreover, the friction component has an initial contact portion and a main friction surface. The initial contact portion protrudes axially from the first side surface and slides in contact with the side surface of the input-side rotating body or the output-side rotating body. After the initial contact portion wears down, the main friction surface slides in contact with the side surface of the input-side rotating body.

[0019] (7) Preferably, the pressing member has an abutting portion that abuts against the second side of the friction member. Moreover, when viewed from the direction along the rotation axis, the abutting portion overlaps with the initial contact portion of the friction member.

[0020] Invention Effects

[0021] In the present invention described above, a friction component that stabilizes the initial hysteresis torque can be obtained. Attached Figure Description

[0022] Figure 1This is a cross-sectional view of a clutch disc assembly having a hysteresis torque generating mechanism according to an embodiment of the present invention.

[0023] Figure 2 yes Figure 1 The main view.

[0024] Figure 3 This is the front view of the output-side rotating body and the damping mechanism.

[0025] Figure 4 yes Figure 1 A magnified view of a portion of the image.

[0026] Figure 5 Is with Figure 4 Different Figure 1 A magnified view of a portion of the image.

[0027] Figure 6 This is a partial cross-sectional view of a friction washer.

[0028] Figure 7 The friction washer of other embodiments of the present invention is related to... Figure 6 The corresponding diagram.

[0029] Explanation of reference numerals in the attached figures

[0030] 2: Input side rotating body (first rotating body); 3: Output side rotating body (second rotating body); 4: Damping mechanism; 11: Clutch plate (rotating component); 31: High-rigidity spring; 32: Low-rigidity spring; 33: Hysteresis generating mechanism; 37: Second friction washer (friction component); 39: Third friction washer (friction component); 37a, 39a: Body; 38: Second conical spring (pressing component); 38a: Abutment part; 41, 42: Friction element; 41a, 42a: Main friction surface; 41b, 42b: Initial contact part. Detailed Implementation

[0031] [Overall Structure]

[0032] Figure 1 This is a cross-sectional view of a clutch disc assembly 1 (an example of a power transmission device) having a hysteresis torque generating mechanism according to an embodiment of the present invention. Additionally, Figure 2 This is its main view. Figure 1 The OO line is the rotation axis of clutch disc assembly 1. Additionally, in Figure 1 The engine and flywheel (not shown) are located on the left side. Figure 1 The right side is equipped with a transmission (not shown).

[0033] The clutch disc assembly 1 includes an input-side rotating body 2, an output-side rotating body 3, and a damping mechanism 4.

[0034] [Input side rotation 2]

[0035] The input-side rotating body 2 has a clutch disc 10, a clutch plate 11, and a fixed plate 12.

[0036] <Clutch Disc 10>

[0037] The clutch disc 10 has a pair of annular friction lining members 14 and a buffer plate 15. The pair of friction lining members 14 are fixed to both sides of the buffer plate 15 by rivets 16. In addition, the buffer plate 15 is fixed to the outer periphery of the clutch plate 11 by rivets 17.

[0038] <Clutch plate 11 and fixing plate 12>

[0039] The clutch plate 11 and the fixing plate 12 are circular plate-shaped components, axially spaced at a predetermined interval, and fixed to each other by rivets 17. The clutch plate 11 and the fixing plate 12 each have four retaining portions 11a and 12a in opposite positions. The four retaining portions 11a and 12a are arranged at predetermined intervals in the circumferential direction.

[0040] A portion of the outer periphery of the fixing plate 12 has a stop portion 12b that bends toward the clutch plate 11 and extends axially, and a fixing portion 12c that bends further toward the inner periphery from the stop portion 12b. The stop portion 12b constitutes a stopping mechanism described later. As mentioned above, the fixing portion 12c is fixed to the clutch plate 11 together with the buffer plate 15 by rivets 17.

[0041] [Output-side Rotating Body 3]

[0042] The output-side rotating body 3 is capable of rotating relative to the input-side rotating body 2 and has a splined hub 20 and a hub flange 21 (an example of the first rotating body).

[0043] <Splined Hub 20>

[0044] The splined hub 20 has a cylindrical portion 23 and a flange 24. A spline hole 23a is formed on the inner circumferential surface of the cylindrical portion 23. This spline hole 23a can engage with the input shaft (not shown) of the transmission. The flange 24 extends radially outward from approximately the axial center of the cylindrical portion 23. A plurality of peripheral teeth 24a and a plurality of cuts 24b are formed on the outer circumferential surface of the flange 24.

[0045] <Hub Flange 21>

[0046] The hub flange 21 is formed in the shape of a circular plate and is disposed on the outer periphery of the splined hub 20. The hub flange 21 is positioned axially between the clutch plate 11 and the fixed plate 12. Figure 2 as well as Figure 3As shown, the hub flange 21 has an annular portion 26 and four protrusions 27. A window 27a is formed in each of the four protrusions 27. Furthermore, a stop slit 27b is formed on the outer peripheral surface of each of the four protrusions 27, except for the central portion in the circumferential direction. The stop portion 12b of the fixing plate 12 passes through this slit 27b in the axial direction. That is, the stop portion 12b of the fixing plate 12 and the circumferential end face of the slit 27b constitute a stop mechanism 28 that limits the relative torsional angle between the clutch plate 11, the fixing plate 12, and the hub flange 21 within a specified range.

[0047] Furthermore, multiple inner peripheral teeth 21a and multiple cuts 21b are formed on the inner circumferential surface of the hub flange 21. The multiple inner peripheral teeth 21a engage with the outer peripheral teeth 24a of the spline hub 20 with a predetermined clearance. The cuts 21b are formed at a position radially opposite to the cuts 24b of the spline hub 20. Therefore, the spring receiving portion 29 is formed by the cuts 24b and 21b of the spline hub 20 and the hub flange 21.

[0048] [Damping Mechanism 4]

[0049] The damping mechanism 4 has four high-stiffness springs 31 and two low-stiffness springs 32, and a hysteresis torque generating mechanism (hereinafter referred to as "hysteresis generating mechanism") 33.

[0050] <High-stiffness spring 31 and low-stiffness spring 32>

[0051] A high-stiffness spring 31 is housed in the aperture 27a of the hub flange 21 and held radially and axially by the retaining portions 11a and 12a of the clutch plate 11 and the fixing plate 12. A low-stiffness spring 32 is housed in a spring housing 29 formed by cutouts 24b and 21b of the splined hub 20 and the hub flange 21. Furthermore, although detailed descriptions are omitted, two of the four high-stiffness springs 31 are configured to be shorter than the circumferential length of the aperture 27a. Additionally, the end faces of the four high-stiffness springs 31 abut against the end faces of the retaining portions 11a and 12a of the clutch plate 11 and the fixing plate 12. This structure enables multi-stage torsional characteristics.

[0052] <Lag-generating mechanism 33>

[0053] like Figure 4 as well as Figure 5 As shown, the hysteresis generating mechanism 33 has a first friction washer 35, a first conical spring 36, a second friction washer 37 (one example of a friction component), a second conical spring 38, and a third friction washer 39 (another example of a friction component).

[0054] - First friction washer 35 -

[0055] The first friction washer 35 is disposed axially between the flange 24 of the splined hub 20 and the inner periphery of the fixing plate 12, and is disposed on the outer periphery of the cylindrical portion 23. The first friction washer 35 is made of resin. The first friction washer 35 has an annular body 35a and a plurality of protrusions 35b.

[0056] The body 35a abuts against the transmission side of the flange 24, and a first conical spring 36 is disposed between the body 35a and the fixing plate 12. The first conical spring 36 is compressed axially between the body 35a and the fixing plate 12. Therefore, the friction surface of the first friction washer 35 is pressed against the flange 24 by the first conical spring 36.

[0057] Multiple protrusions 35b extend radially outward from the body 35a. These protrusions 35b engage with the recesses 37c (described later) of the second friction washer 37. Thus, the first friction washer 35 and the second friction washer 37 can rotate integrally.

[0058] -Second friction washer 37-

[0059] The second friction washer 37 is disposed between the inner periphery of the hub flange 21 and the inner periphery of the fixing plate 12, and is disposed on the outer periphery side of the first friction washer 35. The second friction washer 37 is made of resin and has an annular body 37a, a plurality of engaging portions 37b, and a recess 37c.

[0060] The body 37a abuts against the transmission side of the hub flange 21. The second conical spring 38 is positioned between the body 37a and the fixing plate 12 in a compressed state. Thus, the body 37a is pressed against the hub flange 21 by the second conical spring 38.

[0061] Figure 6 A portion of the second friction washer 37 and the third friction washer 39 are shown in enlarged view. Figure 6 As shown, on the side of the hub flange 21 of the body 37a, the annular friction element 41 is fixed by embedding.

[0062] The friction element 41 has a main friction surface 41a and an initial contact portion 41b. The main friction surface 41a is formed on the side of the hub flange 21. The initial contact portion 41b is formed in a radial direction on a portion of the main friction surface 41a and protrudes towards the hub flange 21. Specifically, the initial contact portion 41b is annular, and the surface on the side of the hub flange 21 is flat. Furthermore, the radial position of the abutment portion 38a, where the second conical spring 38 abuts against the body 37a of the second friction washer 37, is located between the inner diameter Di and the outer diameter Do of the initial contact portion 41b. Therefore, the initial contact portion 41b is effectively pressed against the side of the hub flange 21 by the second conical spring 38.

[0063] Furthermore, in this embodiment, the protrusion height h of the initial contact portion 41b from the main friction surface 41a is set to 0.04 mm. The protrusion height of the initial contact portion 41b is preferably set appropriately according to the type of friction element.

[0064] Based on the structure of this second friction washer 37, in the initial stage of use, only the initial contact portion 41b of the friction element 41 actually makes frictional contact with the hub flange 21. Therefore, the hysteresis torque generated by this frictional contact is stabilized at the desired design value. Moreover, as the initial contact portion 41b wears down with use, the main friction surface 41a, including the area of ​​the initial contact portion 41b, makes sliding contact with the hub flange 21.

[0065] The engaging portion 37b extends from the inner periphery of the body 37a toward the transmission side, passing through the hole in the fixing plate 12. Thus, the second friction washer 37 and the fixing plate 12 can rotate integrally.

[0066] A recess 37c is formed on the transmission side of the inner periphery of the body 37a. The protrusion 35b of the first friction washer 35 engages with the recess 37c. Therefore, the first friction washer 35 can rotate integrally with the fixing plate 12 via the second friction washer 37.

[0067] Furthermore, the force applied by the first conical spring 36 is designed to be smaller than that applied by the second conical spring 38. Additionally, the coefficient of friction of the first friction washer 35 is lower than that of the second friction washer 37. Therefore, the hysteresis torque generated by the first friction washer 35 is significantly reduced compared to the hysteresis torque generated by the second friction washer 37.

[0068] - Third friction washer 39 -

[0069] A third friction washer 39 is disposed between the flange 24 of the splined hub 20 and the inner periphery of the clutch plate 11, and on the outer periphery of the cylindrical portion 23. The third friction washer 39 is, for example, made of resin. The third friction washer 39 has an annular body 39a and a plurality of engaging portions 39b.

[0070] One side of the body 39a abuts against the engine side of the flange 24 and the hub flange 21, while the other side abuts against the transmission side of the clutch plate 11. The engaging portion 39b extends from the body 39a toward the engine side and passes through a hole formed in the clutch plate 11. The third friction washer 39 can rotate integrally with the clutch plate 11 using the engaging portion 39b. Furthermore, the body 39a engages with the center hole of the clutch plate 11 in a manner that prevents relative rotation, and its inner circumferential surface can slidably abut against the outer circumferential surface of the cylindrical portion 23 of the splined hub 20. That is, the clutch plate 11 is radially positioned by the splined hub 20 via the third friction washer 39.

[0071] Here as Figure 6As shown, the annular friction element 42 is fixed to the side of the hub flange 21 of the body 39a of the third friction washer 39 by an embedded molding.

[0072] The friction element 42 of the third friction washer 39 has a substantially the same structure as the friction element 41 of the second friction washer 37. Specifically, the friction element 42 has a main friction surface 42a and an initial contact portion 42b. The main friction surface 42a is formed on the surface on the hub flange 21 side. The initial contact portion 42b is formed in an annular shape in a radial portion of the main friction surface 42a and protrudes towards the hub flange 21 side. Furthermore, the surface of the initial contact portion 42b is flat. Additionally, the protrusion height h of the initial contact portion 42b from the main friction surface 42a is the same as that of the friction element 41 of the second friction washer 37.

[0073] With the structure of this third friction washer 39, as described above, the initial contact portion 42b does indeed make frictional contact with the hub flange 21 during the initial stage of use. On the other hand, as the initial contact portion 42b wears down with use, the main friction surface 42a, including the area of ​​the initial contact portion 42b, makes sliding contact with the hub flange 21.

[0074] As described above, the second friction washer 37 and the third friction washer 39 constitute the large hysteresis generating mechanism 45, and the first friction washer 35 and the third friction washer 39 constitute the small hysteresis generating mechanism 46. Moreover, when the input-side rotating body 2, the hub flange 21, and the splined hub 20 rotate relative to each other, the large hysteresis generating mechanism 45 and the small hysteresis generating mechanism 46 generate hysteresis torque, and the torsional vibration is attenuated and absorbed.

[0075] [action]

[0076] When the input torque or torque variation is small, only the low-stiffness spring 32 is compressed, and the hysteresis torque is generated by the small hysteresis generating mechanism 46. As a result, low stiffness and low hysteresis torque characteristics are obtained in the region of small torsion angle.

[0077] When the torque increases and the torsion angle increases, the outer peripheral teeth 24a of the flange 24 of the splined hub 20 abut against the inner peripheral teeth 21a of the hub flange 21. Therefore, when the torsion angle increases, the splined hub 20 and the hub flange 21 rotate as a unit.

[0078] As the torsional angle increases further from this state, relative rotation occurs between the hub flange 21 and the input-side rotating body 2, compressing two of the four high-stiffness springs 31. At this time, in addition to the small hysteresis generating mechanism 46, a hysteresis torque is also generated in the large hysteresis generating mechanism 45.

[0079] Furthermore, as the torsion angle increases further, all the high-rigidity springs 31 are compressed. Therefore, characteristics of higher rigidity and high hysteresis torque are obtained.

[0080] In the aforementioned operation, during the initial stage of use, only the initial contact portions 41b and 42b of the friction elements 41 and 42 make frictional contact with the second friction washer 37 and the third friction washer 39. That is, the hysteresis torque is generated only using the intentionally designed portions. Therefore, the desired and stable initial hysteresis torque can be obtained.

[0081] Furthermore, as the initial contact portions 41b and 42b wear down with use, the main friction surfaces 41a and 42a, including the initial contact portions 41b and 42b, come into frictional contact with the second friction washer 37 and the third friction washer 39. Therefore, the desired stable hysteresis torque is also obtained here.

[0082] [Other Implementation Methods]

[0083] This invention is not limited to the above embodiments, and various modifications or alterations can be made without departing from the scope of this invention.

[0084] (a) In the described embodiment, in the second and third friction washers, the body and the friction element are integrally formed by insert molding, but they can also be formed from a single component. Figure 7 This example is illustrated below. In this example, a portion of the friction surfaces 47a and 49a (corresponding to the main friction surfaces) of the second friction washer 47 and the third friction washer 49 protrudes towards the hub flange 21 to form initial contact portions 47b and 49b. The specific shape and structure of the initial contact portions 47b and 49b are the same as in the embodiment described above.

[0085] (b) The shape of the initial contact portion is not limited to the embodiment described above. For example, the surface of the initial contact portion may be formed as a sphere instead of a flat surface. In addition, the initial contact portion may not be a continuous ring, but may be intermittently arranged in a ring shape.

[0086] (c) In the embodiment described above, the contact position of the conical spring is located between the inner diameter and the outer diameter of the initial contact portion. However, the contact position of the conical spring may be located either inside the inner diameter of the initial contact portion or outside the outer diameter.

[0087] (d) In the embodiment described herein, the friction element of the present invention is applied to a clutch disc assembly, but it can also be applied to the hysteresis generation mechanism of other vibration absorption devices.

[0088] (e) In the embodiment described above, an initial contact portion and a main friction surface are provided on the friction component, but the initial contact portion and the main friction surface may also be provided on the friction surface of the hub flange.

Claims

1. A hysteresis torque generation mechanism characterized by, Possessing: a first rotating body having a sliding surface; and a second rotating body disposed in opposition to the first rotating body and sliding on the sliding surface of the first rotating body to generate a hysteresis torque, the second rotating body having an outer peripheral side main friction surface provided to an outer peripheral portion and an initial contact portion provided to a radially inner side of the outer peripheral side main friction surface, the initial contact portion being provided protruding to the first rotating body side and in sliding contact with the sliding surface of the first rotating body, the outer peripheral side main friction surface being in sliding contact with the sliding surface of the first rotating body after the initial contact portion is worn.

2. The hysteresis torque generation mechanism according to claim 1, wherein the first rotating body is a component to which a power is input and which transmits the input power to a component on an output side, the second rotating body is a friction component capable of relative rotation with respect to the first rotating body.

3. The hysteresis torque generation mechanism according to claim 1 or 2, wherein the initial contact portion is formed in a ring shape.

4. The hysteresis torque generation mechanism according to any one of claims 1 to 3, wherein the second rotating body has: a body; and a friction member fixed to the body and having the initial contact portion and the outer peripheral side main friction surface on a surface.

5. The hysteresis torque generation mechanism according to claim 4, wherein the body is made of resin, the friction member is insert-molded in the body.

6. A power transmission device characterized by comprising: Possessing: an input side rotating body; an output side rotating body disposed so as to be capable of relative rotation with respect to the input side rotating body; a plurality of elastic members elastically linking the input side rotating body and the output side rotating body in a rotational direction; and a hysteresis torque generation mechanism generating a hysteresis torque when the input side rotating body and the output side rotating body are relatively rotated, the hysteresis torque generation mechanism having: a friction component disposed between the input side rotating body and the output side rotating body in an axial direction; and a pressing component pressing a first side surface of the friction component toward a side surface of the output side rotating body, the friction component having a main friction surface provided to an outer peripheral portion and an initial contact portion provided to a radially inner side of the main friction surface, the initial contact portion being provided protruding in the axial direction at the first side surface and in sliding contact with a sliding surface of the output side rotating body, the main friction surface being in sliding contact with the sliding surface of the output side rotating body after the initial contact portion is worn.

7. The power transmission apparatus according to claim 6, wherein the pressing component has an abutting portion abutting against a second side surface of the friction component, the abutting portion overlaps the initial contact portion of the friction component when viewed in a direction along a rotational axis. ​

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