Power transmission device

Abstract

To provide a power transmission device which can prolong a life of an urging member.SOLUTION: A first plate is arranged on a first side in an axial direction with respect to a flange plate. A second plate is arranged on a second side in the axial direction with respect to the flange plate. An elastic member elastically connects an input rotor and an output rotor. A first shaft is attached to a hub. A first helical gear is fixed to the first shaft. The first helical gear is configured such that a thrust force toward the first side in the axial direction is applied when rotated in a rotation direction. A second shaft extends along the first shaft. A second helical gear is attached to the second shaft. The second helical gear engages with the first helical gear. An urging member is arranged between the flange plate and the second plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power transmission device. [Background technology]

[0002] The power transmission device is configured to absorb and attenuate torque fluctuations from an internal combustion engine. The power transmission device includes first and second plates, an output rotor, and a plurality of elastic members (see, for example, Patent Document 1). Each elastic member elastically connects the first and second plates to the output rotor.

[0003] In addition, to suppress resonance, the power transmission device has a friction member and a biasing member. The friction member and the biasing member are disposed between the first plate and the flange plate of the output member. The biasing member biases the friction member toward the flange plate. The friction member frictionally engages with the flange plate, thereby suppressing resonance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-227222 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a demand for a longer lifespan for the biasing members used in power transmission devices. Therefore, an object of the present invention is to provide a power transmission device that enables a longer lifespan for the biasing members. [Means for solving the problem]

[0006] A power transmission device according to a first aspect includes an output rotor, an input rotor, an elastic member, a first shaft, a first helical gear, a second shaft, a second helical gear, and an urging member. The output rotor has a hub and a flange plate. The input rotor has a first plate and a second plate. The first plate is disposed on a first axial side relative to the flange plate. The second plate is disposed on a second axial side relative to the flange plate. The elastic member elastically connects the input rotor and the output rotor. The first shaft is attached to the hub. The first helical gear is fixed to the first shaft. The first helical gear is configured to exert a thrust force toward the first axial side when rotated in a rotational direction. The second shaft extends along the first shaft. The second helical gear is attached to the second shaft. The second helical gear meshes with the first helical gear. The urging member is disposed between the flange plate and the second plate.

[0007] With this configuration, when the power transmission device rotates due to torque from a prime mover such as an internal combustion engine, the first helical gear rotates in the rotational direction, and a thrust force acting on the first helical gear toward the first axial side is applied to the first helical gear. As a result, a load acting on the flange plate toward the first axial side is applied. Because the disc spring is disposed between the flange plate and the second plate, the disc spring is not subjected to an axial load resulting from the thrust force acting on the first helical gear. As a result, wear on the disc spring is suppressed, and the disc spring's lifespan can be extended.

[0008] A power transmission device according to a second aspect is the power transmission device according to the first aspect, further comprising an electric motor attached to the second shaft.

[0009] A power transmission device according to a third aspect is the power transmission device according to the first or second aspect, and is configured as follows: The first shaft extends from the hub to a first side in the axial direction. The first helical gear is configured so that, when rotated in the rotational direction, a thrust force acts in the direction in which the first shaft extends.

[0010] A power transmission device according to a fourth aspect is the power transmission device according to any one of the first to third aspects, and is configured as follows: The twist direction of the first helical gear is the same as the rotation direction.

[0011] A power transmission device according to a fifth aspect is the power transmission device according to any one of the first to fourth aspects, configured as follows: The first helical gear has an outer diameter larger than that of the second helical gear.

[0012] A sixth aspect of the present invention relates to the power transmission device of any one of the first to fifth aspects, and further includes a friction member. The friction member is disposed between the biasing member and the flange plate. The biasing member biases the friction member toward the flange plate. [Effects of the Invention]

[0013] According to the present invention, the life of the biasing member can be extended. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. [Figure 2] Enlarged cross-sectional view of the power transmission device [Figure 3] FIG. 10 is a cross-sectional view of a power transmission device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] The power transmission device 100 according to this embodiment will be described below with reference to the drawings. In the following description, the axial direction refers to the direction in which the rotation axis O of the power transmission device 100 extends. The circumferential direction refers to the circumferential direction of a circle centered on the rotation axis O, and the radial direction refers to the radial direction of a circle centered on the rotation axis O. The first axial side refers to the direction of a thrust force acting on the first helical gear 14 when the first helical gear 14, which will be described later, rotates in the rotational direction, and in this embodiment, this is the right side in FIG. 1. The second axial side refers to the side opposite to the first axial side.

[0016] 1 is a cross-sectional view of a power transmission device 100. As shown in FIG. 1, the power transmission device 100 includes a damper unit 11, a torque limiter unit 12, a first shaft 13, a first helical gear 14, a second shaft 15, a second helical gear 16, and an electric motor 17.

[0017] The damper unit 11 and the torque limiter unit 12 basically rotate integrally with each other. The power transmission 100 is provided between an internal combustion engine (not shown) and an output member (not shown). The output member is, for example, a transmission. The power transmission 100 is attached to a flywheel 101. In FIG. 1 , the internal combustion engine is disposed on the left side of the power transmission 100, and the output member is disposed on the right side of the power transmission 100. The power transmission 100 is configured to limit the torque transmitted between the internal combustion engine and the output member, and to attenuate torque fluctuations.

[0018] [Damper unit] 2 is a cross-sectional view of the damper unit 11 and the torque limiter unit 12. As shown in FIG. 2, the damper unit 11 is attached to the torque limiter unit 12. The damper unit 11 is configured to damp rotation fluctuations. The damper unit 11 has an output rotor 2, an input rotor 3, a plurality of elastic members 4, a first friction member 5, a second friction member 6 (an example of a friction member), a first disc spring 7 (an example of a biasing member), and a friction disc 8.

[0019] <Output rotor> The output rotor 2 is configured to transmit torque from the input rotor 3 to an output member. The output rotor 2 is disposed rotatably about a rotation axis O.

[0020] The output rotor 2 has a flange plate 21 and a hub 22. The flange plate 21 and the hub 22 are configured to rotate integrally.

[0021] The flange plate 21 has an opening 211 in the center. That is, the flange plate 21 is annular. The flange plate 21 also has a plurality of accommodating holes 212. The accommodating holes 212 are arranged at intervals in the circumferential direction. Each accommodating hole 212 is configured to accommodate an elastic member 4.

[0022] The hub 22 is cylindrical. The hub 22 extends in the axial direction. The hub 22 passes through openings of a first plate 31 and a second plate 32 (described later) in the axial direction. The hub 22 has a spline hole 221 extending in the axial direction. The first shaft 13 is spline-fitted into this spline hole 221.

[0023] The hub 22 is press-fitted into the opening 211 of the flange plate 21. Therefore, the hub 22 rotates integrally with the flange plate 21. In other words, the hub 22 does not rotate relative to the flange plate 21. The hub 22 may be formed integrally with the flange plate 21 using a single member.

[0024] <Input rotor> The input rotor 3 is arranged to be rotatable relative to the output rotor 2. The input rotor 3 has a first plate 31 and a second plate 32. The first plate 31 and the second plate 32 are both annular members with an opening in the center. The hub 22 of the output rotor 2 extends through the openings of the first plate 31 and the second plate 32.

[0025] The first plate 31 and the second plate 32 rotate integrally with each other, and are immovable relative to each other in the axial direction.

[0026] The first plate 31 and the second plate 32 are arranged at an interval in the axial direction. The flange plate 21 is arranged between the first plate 31 and the second plate 32 in the axial direction. The first plate 31 and the second plate 32 are arranged to be rotatable relative to the flange plate 21.

[0027] The first plate 31 is disposed on a first axial side relative to the flange plate 21. The first plate 31 is disposed axially apart from the flange plate 21. The second plate 32 is disposed axially on a second axial side relative to the flange plate 21. The second plate 32 is disposed axially apart from the flange plate 21.

[0028] The first plate 31 and the second plate 32 each have a plurality of window portions 311, 321. The window portions 311, 321 are arranged at intervals from each other in the circumferential direction. Each window portion 311, 321 is configured to accommodate an elastic member 4. Each window portion 311, 321 is arranged at a position overlapping with each accommodation hole 212 when viewed in the axial direction.

[0029] <Elastic material> The elastic member 4 is configured to elastically connect the input rotor 3 and the output rotor 2 in the rotational direction. That is, the elastic member 4 elastically connects the flange plate 21 and the first and second plates 31, 32 in the rotational direction. The elastic member 4 is, for example, a coil spring.

[0030] The elastic member 4 is housed in the housing hole 212 of the flange plate 21. The elastic member 4 is housed in the window portion 311 of the first plate 31 and also in the window portion 321 of the second plate 32.

[0031] <First friction member> The first friction member 5 is disposed between the flange plate 21 and the first plate 31 in the axial direction. The first friction member 5 is annular and extends in the circumferential direction. The first friction member 5 is configured to rotate integrally with the flange plate 21. Note that the first friction member 5 may rotate relative to the flange plate 21 within a predetermined range.

[0032] The first friction member 5 is disposed so as to be rotatable relative to the first plate 31. When the first friction member 5 rotates relative to the first plate 31, a friction force is generated.

[0033] <Second friction member> The second friction member 6 is disposed between the flange plate 21 and the second plate 32 in the axial direction. More specifically, the second friction member 6 is disposed between the flange plate 21 and the first disc spring 7. The second friction member 6 is annular and extends in the circumferential direction. The second friction member 6 is configured to rotate integrally with the second plate 32. The second friction member 6 is disposed so as to be rotatable relative to the flange plate 21.

[0034] <Disc spring> The first disc spring 7 is disposed between the flange plate 21 and the second plate 32. That is, the first disc spring 7 is disposed on the second axial side relative to the flange plate 21. More specifically, the first disc spring 7 is disposed between the second friction member 6 and the second plate 32. The first disc spring 7 biases the second friction member 6 in the axial direction toward the flange plate 21. As a result, a frictional force is generated when the second friction member 6 rotates relative to the flange plate 21.

[0035] <Friction disc> The friction disc 8 is attached to the outer circumferential end of the input rotor 3. More specifically, the friction disc 8 is attached to the first plate 31 by a fastening member 37. The friction disc 8 may also be attached to the second plate 32. The friction disc 8 rotates integrally with the input rotor 3. An example of the fastening member 37 is a rivet.

[0036] The friction disc 8 is annular and includes a support plate 81, a first friction material 82, and a second friction material 83. The support plate 81, the first friction material 82, and the second friction material 83 rotate integrally with each other.

[0037] The support plate 81 is attached to the first plate 31. For example, the support plate 81 is attached to the first plate 31 by a fastening member 37. Note that the support plate 81 is a separate member from the first plate 31, but the support plate 81 may be configured integrally with the first plate 31 as a single member.

[0038] The first and second friction materials 82, 83 are annular. The first friction material 82 is attached to one side surface of the support plate 81, and the second friction material 83 is attached to the other side surface of the support plate 81. The first and second friction materials 82, 83 rotate integrally with the support plate 81.

[0039] When torque equal to or greater than a predetermined value is input to the power transmission device 100, the friction disc 8 slides on the side plate 91 and the pressure plate 93 via the first and second friction materials 82, 83, and rotates relative to the side plate 91 and the pressure plate 93. On the other hand, when torque less than the predetermined value is input, the friction disc 8 rotates integrally with the side plate 91 and the pressure plate 93.

[0040] [Torque limiter unit] The torque limiter unit 12 is disposed rotatably about a rotation axis O. The torque limiter unit 12 is disposed on a first axial side of the flywheel 101. The torque limiter unit 12 is annular. The torque limiter unit 12 is attached to the flywheel 101.

[0041] The torque limiter unit 12 is configured to limit the torque transmitted between the flywheel 101 and the damper unit 11. In other words, the torque limiter unit 12 is configured to restrict the transmission of torque equal to or greater than a predetermined value in the power transmission device 100. The torque limiter unit 12 is configured to frictionally engage with the friction disc 8. The torque limiter unit 12 also sandwiches the friction disc 8 in the axial direction.

[0042] The torque limiter unit 12 includes a side plate 91 , a cover plate 92 , a pressure plate 93 , and a second disc spring 94 .

[0043] The side plate 91 and the cover plate 92 are attached to the flywheel 101. The side plate 91 and the cover plate 92 rotate integrally with the flywheel 101. The side plate 91 and the cover plate 92 are annular. The cover plate 92 is disposed on the second axial side of the side plate 91. The thickness of the cover plate 92 is thinner than the thickness of the side plate 91.

[0044] The pressure plate 93 is annular. The pressure plate 93 is disposed between the side plate 91 and the cover plate 92 in the axial direction. More specifically, the pressure plate 93 is disposed between the second friction material 83 and the second disc spring 94 in the axial direction. The pressure plate 93 is configured to rotate integrally with the side plate 91. The pressure plate 93 is movable in the axial direction relative to the side plate 91.

[0045] The second disc spring 94 is disposed between the cover plate 92 and the pressure plate 93 in the axial direction. The second disc spring 94 urges the pressure plate 93 toward the first side in the axial direction. In other words, the second disc spring 94 urges the pressure plate 93 toward the friction disc 8. As a result, the friction disc 8 is sandwiched between the pressure plate 93 and the side plate 91.

[0046] [First shaft] The first shaft 13 is attached to the hub 22 of the output rotor 2. Specifically, the first shaft 13 is spline-fitted into a spline hole 221 of the hub 22. The first shaft 13 rotates integrally with the hub 22. The first shaft 13 extends from the hub 22 to a first side in the axial direction. The rotation axis of the first shaft 13 is coaxial with the rotation axis O of the power transmission device 100.

[0047] [First helical gear] 1, the first helical gear 14 is fixed to the first shaft 13 and rotates integrally with the first shaft 13. The first helical gear 14 also moves integrally with the first shaft 13 in the axial direction.

[0048] The first helical gear 14 meshes with the second helical gear 16. When the first helical gear 14 rotates and transmits torque to the second helical gear 16, a thrust force acts on the first helical gear 14 and the second helical gear 16. When the first helical gear 14 rotates in the rotational direction due to torque from the internal combustion engine, that is, when torque is transmitted from the first helical gear 14 to the second helical gear 16, the direction of the thrust force acting on the first helical gear 14 is defined as the first axial side. In other words, the first helical gear 14 is configured so that a thrust force acts on the first axial side when it rotates in the rotational direction due to torque from the internal combustion engine.

[0049] The rotation direction is the direction in which the first helical gear 14 rotates when the internal combustion engine rotates. In other words, the rotation direction is the direction in which the first helical gear 14 rotates when torque is transmitted from the internal combustion engine. The internal combustion engine rotates the flywheel 101 in the clockwise direction when viewed along the axial direction from the second axial side. In other words, in this embodiment, the rotation direction is the clockwise direction when viewed along the axial direction from the second axial side.

[0050] The first helical gear 14 is configured so that a thrust force acts in the direction in which the first shaft 13 extends. In other words, the direction of the thrust force acting on the first helical gear 14 is the same as the direction in which the first shaft 13 extends from the hub 22. The twist direction of the first helical gear 14 is the same as the direction of rotation. In other words, the first helical gear 14 is twisted in the direction of rotation. In this embodiment, the first helical gear 14 has a right-handed twist. As a result, when torque from the internal combustion engine is transmitted from the first helical gear 14 to the second helical gear 16, the direction of the thrust force acting on the first helical gear 14 is the same as the direction in which the first shaft 13 extends from the hub 22.

[0051] [Second shaft] The second shaft 15 extends along the first shaft 13. That is, the second shaft 15 extends in the axial direction. The second shaft 15 is disposed radially outward relative to the first shaft 13.

[0052] [Second helical gear] The second helical gear 16 is attached to the second shaft 15. More specifically, the second helical gear 16 is fixed to the second shaft 15. The second helical gear 16 rotates integrally with the second shaft 15. In addition, the second helical gear 16 moves integrally with the second shaft 15 in the axial direction.

[0053] The second helical gear 16 meshes with the first helical gear 14. The second helical gear 16 has a smaller outer diameter than the first helical gear 14. In other words, the first helical gear 14 has a larger outer diameter than the second helical gear 16.

[0054] [Electric motor] The electric motor 17 is attached to the second shaft 15. The electric motor 17 rotates integrally with the second shaft 15. When starting the internal combustion engine, the electric motor 17 outputs torque to rotate the internal combustion engine. When the electric motor 17 does not output torque, the electric motor 17 is rotated by the torque from the internal combustion engine and functions as a generator.

[0055] [Operation] When torque is transmitted from the internal combustion engine, the flywheel 101 rotates, and the torque is transmitted to the first shaft 13 and the first helical gear 14 via the torque limiter unit 12 and the damper unit 11. Torque fluctuations due to the internal combustion engine are absorbed by the damper unit 11.

[0056] A thrust force acting toward the first axial side acts on the first helical gear 14. As a result, a load acting toward the first axial side acts on the flange plate 21 via the first shaft 13. Here, because the first disc spring 7 is disposed on the second axial side of the flange plate 21, no axial load resulting from the thrust force of the first helical gear 14 acts on the first disc spring 7. This suppresses wear on the first disc spring 7 and extends the life of the first disc spring 7.

[0057] Furthermore, when electric motor 17 is driven to rotate in order to start the internal combustion engine, torque from electric motor 17 is transmitted to first helical gear 14 via second shaft 15 and second helical gear 16. Since first helical gear 14 rotates in the rotational direction due to the torque from second helical gear 16, a thrust force acts on first helical gear 14 toward the second side in the axial direction.

[0058] In this way, when torque is input from the electric motor 17, a thrust force toward the second axial direction acts on the first helical gear 14, and a load toward the second axial direction is also applied to the flange plate 21. As a result, an axial load is applied to the first disc spring 7, which is disposed on the second axial side of the flange plate 21. As a result, resonance that is likely to occur when starting the internal combustion engine can be more efficiently suppressed.

[0059] [Variations] The present invention is not limited to the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the present invention. In addition, the following modifications can be simultaneously applied.

[0060] (a) In the above embodiment, the first helical gear 14 is configured so that a thrust force acts in a direction away from the hub 22 (to the right in FIG. 1 ), i.e., the right side in FIG. 1 is the first axial side, but the configuration of the first helical gear 14 is not limited to this.

[0061] For example, as shown in FIG. 3, when the first helical gear 14 rotates in the rotational direction due to torque from the internal combustion engine, a thrust force toward the hub 22 may act on the first helical gear 14. In other words, the left side of FIG. 1 may be the first axial side. The twist direction of the first helical gear 14 is opposite to the rotational direction. In other words, the first helical gear 14 is twisted in the direction opposite to the rotational direction. In this modified example, the first helical gear 14 has a left-handed twist. This makes the direction of the thrust force acting on the first helical gear 14 the same as the direction toward the hub 22.

[0062] In this case, the first plate 31 and the first friction member 5 are disposed on the left side of the flange plate 21, and the second plate 32, the second friction member 6, and the first disc spring 7 are disposed on the right side of the flange plate 21.

[0063] (b) In the above embodiment, the power transmission device 100 includes the torque limiter unit 12, but the configuration of the power transmission device 100 is not limited to this. For example, the power transmission device 100 does not have to include the torque limiter unit 12. [Explanation of symbols]

[0064] 2: Output rotor 21: Flange plate 22: Hub 3: Input rotor 31: First plate 32: Second plate 4: Elastic material 6: Second friction member 7: First disc spring 13: First shaft 14: Gears 15: Second shaft 16: Gears 17: Electric motor 100: Power transmission device

Claims

1. an output rotor having a hub and a flange plate; an input rotor having a first plate disposed on a first side in the axial direction relative to the flange plate, and a second plate disposed on a second side in the axial direction relative to the flange plate; an elastic member that elastically connects the input rotor and the output rotor; a first shaft attached to the hub; a first helical gear fixed to the first shaft and configured to exert a thrust force toward a first side in the axial direction when the first shaft rotates in a rotational direction; a second shaft extending along the first shaft; a second helical gear attached to the second shaft and meshing with the first helical gear; a biasing member disposed between the flange plate and the second plate; A power transmission device comprising:

2. further comprising an electric motor attached to the second shaft; The power transmission device according to claim 1 .

3. the first shaft extends from the hub to a first side in the axial direction; the first helical gear is configured to apply a thrust force in an extension direction of the first shaft when rotated in a rotation direction; The power transmission device according to claim 1 .

4. The twist direction of the first helical gear is the same as the rotation direction. The power transmission device according to claim 1 .

5. the first helical gear has a larger outer diameter than the second helical gear; The power transmission device according to claim 1 .

6. a friction member disposed between the biasing member and the flange plate; The biasing member biases the friction member toward the flange plate. The power transmission device according to claim 1 .

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