Multi-plate clutch

Abstract

To provide a multiple disc clutch which enables further reduction of hysteresis, i.e., a difference of fastening power (difference of transmission torque) between a fastening side and a release side in the multiple disc clutch.SOLUTION: A multiple disc clutch 1 includes: multiple outer plates 11 and multiple inner plates 12 disposed alternately; first fixing members 13 which restrict the outer plates 11 so as to prevent the outer plates 11 from sliding; and second fixing members 14 which restrict the inner plates 12 so as to prevent the inner plates 12 from sliding. The outer plates 11 have first flexible parts 112 which connect first fitting parts 111 formed at the outer periphery side with first friction slide contact parts 113 formed at the inner periphery side, have rigidity lower than those of the first fitting parts 111 and the first friction slide contact parts 113, and may deflect in an axial direction. The inner plates 12 have second flexible parts 122 which connect second fitting parts 121 formed at the inner periphery side with second friction slide contact parts 123 formed at the outer periphery side, have rigidity lower than those of the second fitting parts 121 and the second friction slide contact parts 123, and may deflect in the axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004] ,

[0005] , ,

[0001] The present invention relates to a multi-plate clutch.

Background Art

[0002] Conventionally, for example, in a power transmission device of an automobile (such as a transfer of an all-wheel drive vehicle (AWD vehicle)), a wet multi-plate clutch that varies the fastening force (transmission torque) according to hydraulic pressure (performs torque transmission and interruption) is widely used between a driving-side rotating member and a driven-side rotating member. In a wet multi-plate clutch, drive plates provided on the driving side and driven plates provided on the driven side are alternately arranged. For example, by applying hydraulic pressure to drive a piston and sliding the drive plate and the driven plate to press them together (frictionally slide), torque is transmitted (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a wet multi-plate clutch, hysteresis occurs due to friction (friction at the fitting portion between the rotating member and the clutch plate) caused by the sliding of the clutch plates (drive plates and driven plates) during fastening and release. That is, a difference occurs in the fastening force (transmission torque) with respect to the hydraulic pressure (the same hydraulic pressure) between the fastening side and the release side (when increasing and decreasing the fastening force). Such hysteresis can be a factor that deteriorates the controllability of the fastening force (transmission torque), and thus improvement (reduction) of hysteresis has been demanded.

[0005] The present invention was made to solve the above-mentioned problems, and aims to provide a multi-plate clutch that can reduce hysteresis in a multi-plate clutch, that is, the difference in fastening force (transmission torque difference) between the fastening side and the release side. [Means for solving the problem]

[0006] A multi-plate clutch according to one aspect of the present invention comprises a plurality of outer plates and a plurality of inner plates arranged alternately in the axial direction, a first fixing member that restricts each of the plurality of outer plates from sliding in the axial direction, and a second fixing member that restricts each of the plurality of inner plates from sliding in the axial direction, wherein each of the plurality of outer plates has a first fitting portion formed on its outer circumference that fits with one of the rotating members, a first friction sliding contact portion formed on its inner circumference, and a first flexible portion that connects the first fitting portion and the first friction sliding contact portion and has lower axial rigidity than the first fitting portion and the first friction sliding contact portion and can bend in the axial direction. The present invention relates to a plurality of inner plates, each having a second fitting portion formed on the inner circumference side that fits with the other rotating member, a second friction sliding portion formed on the outer circumference side that can slide against the first friction sliding portion, and a second flexible portion that connects the second fitting portion and the second friction sliding portion and has lower axial rigidity than the second fitting portion and the second friction sliding portion, and can bend in the axial direction. The first fixing member is attached between adjacent first fitting portions to restrict the first fitting portions from sliding in the axial direction, and the second fixing member is attached between adjacent second fitting portions to restrict the second fitting portions from sliding in the axial direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce hysteresis in a multi-plate clutch, that is, the difference in fastening force (transmission torque difference) between the fastening side and the release side. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing the configuration of a multi-plate clutch according to an embodiment (when fastened). [Figure 2]This is a cross-sectional view showing the configuration of a multi-plate clutch according to an embodiment (when released). [Figure 3] This is a front view showing the outer plate (drive plate) that constitutes the multi-plate clutch according to the embodiment. [Figure 4] This is a front view showing the inner plate (driven plate) that constitutes the multi-plate clutch according to the embodiment. [Figure 5] This figure shows the torque transmission characteristics (hysteresis) of the multi-plate clutch according to the embodiment. [Modes for carrying out the invention]

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. In addition, in each drawing, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0010] First, the configuration of the multi-plate clutch (wet multi-plate clutch) 1 according to this embodiment will be explained using Figures 1 to 4 together. Figure 1 is a cross-sectional view showing the configuration of the multi-plate clutch 1 (engaged state). Figure 2 is a cross-sectional view showing the configuration of the multi-plate clutch 1 (disengaged state). Figure 3 is a front view (viewed from the axial direction) showing the outer plate (drive plate) 11 that constitutes the multi-plate clutch 1. Figure 4 is a front view (viewed from the axial direction) showing the inner plate (driven plate) 12 that constitutes the multi-plate clutch 1.

[0011] The multi-plate clutch 1 is used, for example, in power transmission devices (such as automatic transmissions and transfer cases) of automobiles, and varies the fastening force (transmission torque) according to the hydraulic pressure, transmitting and disconnecting the driving force between the driving rotating member and the driven rotating member. In this embodiment, the case in which the multi-plate clutch 1 is applied to the transfer case (transfer clutch) of an all-wheel drive vehicle (AWD vehicle) will be described as an example.

[0012] In particular, the multi-plate clutch 1 has the function of reducing hysteresis in the torque transmission characteristics, that is, the difference in fastening force (transmission torque difference) between the fastening side and the release side. For this reason, the multi-plate clutch 1 does not slide the outer plate 11 and the inner plate 12 (clutch plate) together, but rather flexes the outer plate 11 and the inner plate 12 and makes frictional sliding contact. Furthermore, in the multi-plate clutch 1, a double-push structure is adopted in which the outer plate 11 and the inner plate 12 are pushed from both sides in order to eliminate the bias in the amount of flex of each of the multiple outer plates 11 and inner plates 12 and to flex (press) them more evenly. This will be explained in detail below.

[0013] The multi-plate clutch 1 comprises a plurality of outer plates (drive plates) 11 and inner plates (driven plates) 12 arranged alternately in the axial direction inside the clutch drum 10. More specifically, the outer plates 11 are attached to the clutch drum 10 (corresponding to one of the rotating members), and the inner plates 12 are attached to the rear wheel side output shaft 4 (corresponding to the other rotating member). Each of the plurality of outer plates 11 and the plurality of inner plates 12 is attached by spline fitting.

[0014] Each of the multiple outer plates 11 is an annular plate, and as shown in Figure 3, it has a first fitting portion 111 formed on the outer circumference that fits (spline fitting) with the clutch drum 10 (one of the rotating members), a first friction sliding contact portion (facing) 113 formed on the inner circumference, and a first flexible portion (low rigidity portion) 112 that connects the first fitting portion 111 and the first friction sliding contact portion 113, and has lower axial rigidity than the first fitting portion 111 and the first friction sliding contact portion 113, and can bend in the axial direction (has flexibility).

[0015] The first flexible portion 112 is formed to reduce its rigidity by, for example, having a thinner thickness than the first fitting portion 111 and the first friction sliding contact portion 113. Alternatively, or in addition to reducing the thickness, rigidity may be reduced by, for example, forming a plurality of radially arranged slits (notches) or grooves.

[0016] On the one hand, each of the plurality of inner plates 12 is an annular plate. As shown in FIG. 4, a second fitting portion 121 formed on the inner peripheral side and fitted (spline-fitted) with the rear wheel side output shaft 4 (the other rotating member), and a second friction sliding contact portion (facing) 123 formed on the outer peripheral side and capable of slidingly contacting the first friction sliding contact portion 113 of the outer plate 11, and a second flexible portion (low rigidity portion) 122 that connects the second fitting portion 121 and the second friction sliding contact portion 123, has lower axial rigidity than the second fitting portion 121 and the second friction sliding contact portion 123, and can bend in the axial direction (has flexibility).

[0017] The second flexible portion 122 is formed, for example, with a thickness thinner than that of the second fitting portion 121 and the second friction sliding contact portion 123 in order to reduce rigidity. Instead of or in addition to reducing the thickness, for example, the rigidity may be reduced by forming a plurality of radially arranged slits (notches) or grooves.

[0018] Each of the plurality of outer plates 11 is restricted (fixed) from sliding in the axial direction by a plurality of first fixing members (spacers) 13. The first fixing member 13 is, for example, a ring-shaped member, which is attached between adjacent first fitting portions 111 to restrict (fix) the first fitting portion 111 from sliding in the axial direction.

[0019] Similarly, each of the plurality of inner plates 12 is restricted (fixed) from sliding in the axial direction by a plurality of second fixing members (spacers) 14. The second fixing member 14 is, for example, a ring-shaped member, which is attached between adjacent second fitting portions 121 to restrict (fix) the second fitting portion 121 from sliding in the axial direction.

[0020] Further, the multi-plate clutch 1 has a function of pressing (fastening) the drive plate 11 and the driven plate 12 (clutch plate) from both sides with a single hydraulic chamber 35.

[0021] Therefore, the multi-plate clutch 1 includes a first pressing member 21 and a second pressing member 22 that are movably arranged in the axial direction of a plurality of outer plates 11 and a plurality of inner plates 12, and are opposed to each other with a plurality of first friction contact portions 113 and a plurality of second friction contact portions 123 interposed therebetween.

[0022] Further, the multi-plate clutch 1 includes a first hydraulic piston 31 and a second hydraulic piston 32 that drive the first pressing member 21 and the second pressing member 22 in a direction approaching each other or a direction moving away from each other according to the hydraulic pressure in a single hydraulic chamber 35.

[0023] The first hydraulic piston 31 and the second hydraulic piston 32 are provided coaxially with the outer plate 11 and the inner plate 12 (clutch drum 10) and opposed to each other with the hydraulic chamber 35 interposed therebetween. The first hydraulic piston 31 and the second hydraulic piston 32 are provided slidably in the axial direction inside a piston cylinder 33.

[0024] The hydraulic chamber 35 is defined by the first hydraulic piston 31, the second hydraulic piston 32, the piston cylinder 33, and the input shaft 3. Further, O-rings or the like for holding the hydraulic chamber 35 in a liquid-tight manner are attached to the inner peripheral surfaces and the outer peripheral surfaces (ends) of the first hydraulic piston 31 and the second hydraulic piston 32, respectively. Then, the first hydraulic piston 31 and the second hydraulic piston 32 are driven by a pressing force corresponding to the hydraulic pressure supplied to the hydraulic chamber 35 (that is, a pressing force determined by the multiplication value of the hydraulic pressure and the pressure receiving area (the area of a surface perpendicular to the axis)). The hydraulic pressure (boosted oil) is supplied (or discharged from) the hydraulic chamber 35 through an oil passage 3a formed inside the input shaft 3.

[0025] The first hydraulic piston 31 is connected to a first pressing member 21, which is formed in an annular shape, for example. On the other hand, the second hydraulic piston 32 is connected to a second pressing member 22, which is formed in an annular shape, via a link member (arm) 34. The link member 34 is formed in a cylindrical shape, for example, having an upper surface and a lower surface with a hole formed in the center. That is, when viewed in a cross-section along the axial direction, the link member 34 is formed in a shape such that two rectangles with one side in the longitudinal direction removed are arranged symmetrically with respect to the axis. Also, when viewed in a cross-section along the radial direction, the link member 34 is formed in an annular shape, for example.

[0026] Therefore, when oil is supplied to the hydraulic chamber 35, as the hydraulic chamber 35 expands, the first hydraulic piston 31 and the second hydraulic piston 32 move away from each other (away from one another), as shown in Figure 1, and the first pressing member 21 and the second pressing member 22 move towards each other. Then, pushed by the first pressing member 21 and the second pressing member 22, the first friction sliding contact portion 113 of the outer plate 11 and the second friction sliding contact portion 123 of the inner plate 12 are driven towards each other.

[0027] Here, since the axial movement of the first fitting portion 111 of the outer plate 11 and the second fitting portion 121 of the inner plate 12 is restricted, the first flexible portion 112 of the outer plate 11 and the second flexible portion 122 of the inner plate 12 will bend in the axial direction. Then, the first friction sliding contact portion 113 of the outer plate 11 and the second friction sliding contact portion 123 of the inner plate 12 will slide into contact, and the multi-plate clutch 1 will be engaged. In this way, the drive plate 11 and the driven plate 12 are pressed synchronously from both sides (with approximately the same pressing force) by the first pressing member 21 and the second pressing member 22, causing the first flexible portion 112 and the second flexible portion 122 to bend, and the multi-plate clutch 1 will be engaged.

[0028] On the other hand, when oil is discharged from the hydraulic chamber 35, as the hydraulic chamber 35 contracts, the first friction sliding contact portion 113 of the outer plate 11 and the second friction sliding contact portion 123 of the inner plate 12 separate due to the restoring force (force that tries to return the deflection to its original state) of the first flexible portion 112 of the outer plate 11 and the second flexible portion 122 of the inner plate 12, as shown in Figure 2, and the multi-plate clutch 1 is released. At that time, the first pressing member 21 and the second pressing member 22 are moved away from each other, and the first hydraulic piston 31 and the second hydraulic piston 32 are moved towards each other.

[0029] A drive gear 2DR and a driven gear 2DN that meshes with the drive gear 2DR are attached to the input shaft 3 of the multi-plate clutch 1. Therefore, for example, when torque is input from a transmission or the like, the torque is transmitted to the outer plate 11 via the drive gear 2DR, input shaft 3, and clutch drum 10, and a torque corresponding to the fastening force between the outer plate 11 and the inner plate 12 (the fastening force of the multi-plate clutch 1) is output to the rear wheel side from the rear wheel side output shaft 4.

[0030] On the other hand, the difference between the input torque and the torque output to the rear wheel is output from the driven gear 2DN to the front wheel. Alternatively, the drive gear 2DR and driven gear 2DN described above may be mounted on the rear wheel output shaft 4 instead of the input shaft 3. In other words, the input and output may be reversed.

[0031] Here, the torque transmission characteristics (hysteresis) of the multi-plate clutch 1 are shown in Figure 5. In Figure 5, the horizontal axis represents the directional current (directional hydraulic pressure), and the vertical axis represents the transmitted torque (fastening force). In addition, in Figure 5, the torque transmission characteristics of a comparative example multi-plate clutch (a conventional multi-plate clutch that fastens and disengages by sliding the outer plate and inner plate axially) are also shown as a dashed line.

[0032] As shown by the solid lines in Figure 5, according to the multi-plate clutch 1 of this embodiment, the outer plate 11 and the inner plate 12 flex without sliding, causing the first friction contact portion 113 and the second friction contact portion 123 to be engaged (or disengaged). This reduces friction caused by sliding between the outer plate 11 and the inner plate 12, and reduces hysteresis (difference in fastening force (difference in transmitted torque) between the fastening side and the disengaging side) compared to the multi-plate clutch of the comparative example.

[0033] As described in detail above, according to this embodiment, the outer plate 11 has a first flexible portion 112 which has lower axial rigidity than the first fitting portion 111 and the first friction sliding contact portion 113 and can bend in the axial direction (has flexibility), and the inner plate 12 has a second flexible portion 122 which has lower axial rigidity than the second fitting portion 121 and the second friction sliding contact portion 123 and can bend in the axial direction (has flexibility), thereby restricting the first fitting portion 111 and the second fitting portion 121 from sliding in the axial direction. Therefore, the first flexible portion 112 and the second flexible portion 122 flex without the outer plate 11 and the inner plate 12 sliding against each other, causing the first friction sliding contact portion 113 and the second friction sliding contact portion 123 to be fastened (or released when the flexing returns to its original state). As a result, friction caused by sliding between the outer plate 11 and the inner plate 12 is reduced, and hysteresis is reduced.

[0034] As a result, it becomes possible to reduce hysteresis in the multi-plate clutch 1, that is, the difference in transmitted torque (difference in fastening force) between the fastening side and the release side.

[0035] Furthermore, according to this embodiment, when the multi-plate clutch 1 is released, the first friction contact portion 113 of the outer plate 11 and the second friction contact portion 123 of the inner plate 12 are separated by the restoring force (force that tries to return the deflection to its original state) of the first flexible portion 112 of the outer plate 11 and the second flexible portion 122 of the inner plate 12. Therefore, a return spring can be omitted.

[0036] Furthermore, according to this embodiment, the first pressing member 21 and the second pressing member 22 are arranged opposite each other, sandwiching the first friction sliding contact portion 113 and the second friction sliding contact portion 123, so as to be movable in the axial direction of the outer plate 11 and the inner plate 12. Therefore, the outer plate 11 and the inner plate 12 can be pressed from both sides, and the unevenness in the amount of deflection of the first flexible portion 112 and the second flexible portion 122 can be reduced (the amount of deflection can be made more uniform).

[0037] Furthermore, according to this embodiment, the first pressing member 21 and the second pressing member 22 are driven in a direction toward or toward each other in response to the hydraulic pressure of a single hydraulic chamber 35. Therefore, the outer plate 11 and the inner plate 12 can be pressed from both sides with the same pressing force and in a synchronous manner. In addition, since the pressure-receiving area of ​​the hydraulic pistons (first hydraulic piston 31 and second hydraulic piston 32) can be doubled, it is possible to reduce the supply hydraulic pressure and miniaturize the hydraulic chamber 35.

[0038] According to this embodiment, the thickness of the first flexible portion 112 of the outer plate 11 and the second flexible portion 122 of the inner plate 12 is formed to be thinner than the thickness of the first fitting portion 111, the second fitting portion 121, and the first friction sliding contact portion 113 and the second friction sliding contact portion 123 (or multiple radially arranged slits or grooves are formed). Therefore, the first flexible portion 112 and the second flexible portion 122 can be appropriately flexed, and the first friction sliding contact portion 113 and the second friction sliding contact portion 123 can be accurately brought into sliding contact.

[0039] In this embodiment, the drive gear 2DR and the driven gear 2DN that meshes with the drive gear 2DR are mounted on the input shaft 3. Therefore, for example, when torque is input from a transmission or the like, the torque is transmitted to the outer plate 11 via the drive gear 2DR, the input shaft 3, and the clutch drum 10, and a torque corresponding to the fastening force between the outer plate 11 and the inner plate 12 (the fastening force of the multi-plate clutch 1) is output to the rear wheel side from the rear wheel side output shaft 4. On the other hand, the difference between the input torque and the torque output to the rear wheel side is output to the front wheel side from the driven gear 2DN. Thus, the multi-plate clutch 1 can function as a transfer clutch for an all-wheel drive vehicle (AWD vehicle).

[0040] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiments, the multi-plate clutch 1 was applied to the transfer case (transfer clutch) of an all-wheel drive vehicle (AWD vehicle), but the multi-plate clutch 1 can also be applied to, for example, the main transmission unit of a stepped automatic transmission (step AT), the forward clutch / reverse brake of a continuously variable transmission (CVT), the clutch of a DCT (Dual Clutch Transmission), etc.

[0041] In the above embodiment, in order to reduce the rigidity of the first flexible portion 112 and the second flexible portion 122, the thickness of the first flexible portion 112 and the second flexible portion 122 was made thinner than the thickness of the first fitting portion 111 and the second fitting portion 121, and the first friction sliding contact portion 113 and the second friction sliding contact portion 123 (or multiple radially arranged slits (notches) or grooves were formed). However, the methods for reducing the rigidity of the first flexible portion 112 and the second flexible portion 122 are not limited to these, and for example, a material with lower rigidity and greater flexibility may be used.

[0042] In the above embodiment, the outer plate 11 and the inner plate 12 are configured to be pressed from both sides (double-press). As mentioned above, double-press is preferable, but depending on the requirements, single-press (pressing from one side) may also be used.

[0043] In the above embodiment, hydraulics were used to fasten the multi-plate clutch 1 (i.e., a hydraulic system was adopted), but instead of a hydraulic system, an electromagnetic system or the like may be used.

[0044] In the above embodiment, a return spring is not provided, but a return spring may be provided to the first hydraulic piston 31 and the second hydraulic piston 32 to apply a biasing force in the direction of releasing the multi-plate clutch 1.

[0045] In the above embodiment, the drive gear 2DR and driven gear 2DR are attached to the input shaft 3, but they may also be attached to the rear wheel side output shaft 4 instead of the input shaft 3. In other words, the input and output may be reversed. [Explanation of Symbols]

[0046] 1. Multi-plate clutch 2DR drive gear 2DN Driven Gear 3 Input axes 4. Rear wheel side output shaft 10 Clutch Drum 11. Outer plate (drive plate) 111 First mating section 112 First flexible part 113 First friction sliding contact area (facing) 12 Inner Plate (Driven Plate) 121 Second fitting section 122 Second flexible part 123 Second friction sliding contact area (facing) 13. First fixing member (spacer) 14. Second fixing member (spacer) 21 First pressing member 22 Second pressing member 31. First hydraulic piston 32. Second hydraulic piston 33 Piston Cylinder 34 Link members (arms) 35 Hydraulic chamber

Claims

1. Multiple outer plates and multiple inner plates arranged alternately in the axial direction, A first fixing member restricts each of the aforementioned multiple outer plates so that they cannot slide in the axial direction, The system includes a second fixing member that restricts each of the aforementioned plurality of inner plates from sliding in the axial direction, Each of the aforementioned multiple outer plates is, A first fitting portion is formed on the outer circumference and engages with one of the rotating members, A first friction sliding contact portion formed on the inner circumference, The first fitting portion and the first friction sliding contact portion are connected by a first flexible portion which has lower axial rigidity than the first fitting portion and the first friction sliding contact portion and is capable of bending in the axial direction, Each of the aforementioned multiple inner plates is A second fitting portion is formed on the inner circumference and engages with the other rotating member, A second friction sliding contact portion is formed on the outer circumference and is capable of sliding contact with the first friction sliding contact portion, The second fitting portion and the second friction sliding contact portion are connected by a second flexible portion which has lower axial rigidity than the second fitting portion and the second friction sliding contact portion and is capable of bending in the axial direction, The first fixing member is installed between adjacent first fitting portions and restricts the first fitting portions from sliding in the axial direction. The second fixing member is installed between adjacent second fitting portions and restricts the second fitting portions from sliding in the axial direction. A multi-plate clutch characterized by the following features.

2. The multi-plate clutch according to claim 1, further comprising a first pressing member and a second pressing member, which are arranged opposite to the plurality of first friction sliding contact portions and the plurality of second friction sliding contact portions, so as to be movable in the axial direction of the plurality of outer plates and the plurality of inner plates.

3. The multi-plate clutch according to claim 2, further comprising a hydraulic piston that drives the first pressing member and the second pressing member toward or toward each other in accordance with the hydraulic pressure of a single hydraulic chamber.

4. The first flexible portion is formed to be thinner than the first fitting portion and the first friction sliding portion, or has a plurality of radially arranged slits or grooves formed therein. The multi-plate clutch according to claim 3, characterized in that the second flexible portion is formed to be thinner than the second fitting portion and the second friction sliding contact portion, or has a plurality of radially arranged slits or grooves formed therein.

5. The multi-plate clutch according to any one of claims 1 to 4, further comprising a drive gear attached to one of the rotating members or the other rotating member, and a driven gear that meshes with the drive gear.

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