Power transmission device

Abstract

To provide a power transmission device which can suppress a tooth rattling sound.SOLUTION: A power transmission device comprises: a motor shaft extending in an axial direction; a gear shaft arranged coaxially with the motor shaft, and spline-fit to the moto shaft; a washer arranged between the motor shaft and the gear shaft; and a case for supporting the gear shaft. The washer is brought into contact with each of the motor shaft and the gear shaft in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a power transmission device including a motor shaft, a gear shaft that is spline-fitted with the motor shaft, and an elastic member provided between the motor shaft and the motor shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-141311 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the power transmission device disclosed in Patent Document 1, when the environmental temperature rises, the gap between the end face of the gear shaft and the case supporting the gear shaft expands, which may result in worsening gear rattle noise.

[0005] The present disclosure has been made in consideration of the above, and has an object to provide a power transmission device capable of suppressing gear rattle noise. [Means for solving the problem]

[0006] The power transmission device of the present disclosure comprises a motor shaft extending in the axial direction, a gear shaft arranged coaxially with the motor shaft and spline-fitted with the motor shaft, a spacer arranged between the motor shaft and the gear shaft, and a case supporting the gear shaft, wherein the spacer contacts the motor shaft and the gear shaft, respectively, in the axial direction. Effect of the Invention

[0007] According to the present disclosure, by providing a spacer that contacts the motor shaft and the gear shaft in the axial direction, it is possible to suppress gear rattle noise. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a power transmission device according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a power transmission device according to the second embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing the configuration of a power transmission device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A power transmission device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially the same.

[0010] (Embodiment 1) The configuration of a power transmission device 1 according to a first embodiment will be described with reference to Fig. 1. The power transmission device is applied to, for example, a hybrid electric vehicle (HEV) equipped with an engine and a motor as a power source, a plug-in hybrid electric vehicle (PHEV), and the like.

[0011] The power transmission device 1 includes a motor shaft 11, a gear shaft 12, a spacer 13, a case 14, and bearings 15, 16, and 17.

[0012] The motor shaft 11 is, for example, a rotor shaft of a motor (not shown) and extends in the axial direction. The motor shaft 11 is rotatably supported by a bearing 15.

[0013] The gear shaft 12 is, for example, a reduction shaft, and extends in the axial direction. The gear shaft 12 is disposed coaxially with the motor shaft 11. The gear shaft 12 is spline-fitted with the motor shaft 11. The gear shaft 12 is rotatably supported by bearings 16 and 17.

[0014] Spacer 13 is disposed between motor shaft 11 and gear shaft 12 in the axial and radial directions. Spacer 13 also contacts motor shaft 11 and gear shaft 12 at least in the axial direction. That is, spacer 13 contacts motor shaft 11 and gear shaft 12 in the axial direction, thereby filling the gap between them in the axial direction. Spacer 13 is made of a material that thermally expands / contracts due to temperature changes.

[0015] Moreover, the spacer 13 is made of a material having a larger thermal expansion coefficient than the case 14 . For example, if the case 14 is made of aluminum alloy (ADT4), the thermal expansion coefficient is 21 x 10 -6 In this case, the material of the spacer 13 is, for example, duralumin (coefficient of thermal expansion: 23.6×10 -6 / K), polycarbonate (thermal expansion coefficient: 65×10 -6 / K) etc.

[0016] The case 14 is disposed so as to cover the periphery of the bearing 17 and supports the bearing 17. As a result, the case 14 supports the gear shaft 12 and the motor shaft 11 via the bearing 17. A gap Sp is formed between the case 14 and an end face 121 of the gear shaft 12. The case 14 is made of a material (such as an aluminum alloy) that thermally expands / contracts due to temperature changes.

[0017] Here, for example, in a conventional power transmission device, an elastic member is provided instead of the spacer 13, and the elastic member is not in axial contact with the motor shaft and the gear shaft. Therefore, for example, when the environmental temperature rises, the gap between the case and the gear shaft (corresponding to the gap Sp in FIG. 1) expands due to the difference in linear expansion between the case and the gear shaft. When the gap expands in this way, there is a risk that the rattle noise of the gear pair including the gear shaft will worsen.

[0018] Therefore, in the power transmission device 1, as shown in Fig. 1, a spacer 13 is provided that contacts the motor shaft 11 and the gear shaft 12 in the axial direction. As a result, when, for example, the environmental temperature rises, the spacer 13 thermally expands together with the case 14. That is, when the case 14 thermally expands, the spacer 13 also thermally expands, pushing the gear shaft 12 in the axial direction. As a result, the end face 121 of the gear shaft 12 approaches the case 14, suppressing the expansion of the gap Sp. That is, the increase in the gap Sp due to the thermal expansion of the case 14 can be compensated for by the thermal expansion of the spacer 13.

[0019] In this way, according to the power transmission device 1 of the first embodiment, by providing the spacer 13 that contacts the motor shaft 11 and the gear shaft 12 in the axial direction, it is possible to reliably close the gap Sp that has expanded due to the thermal expansion of the case 14. Therefore, it is possible to suppress the gear rattle noise.

[0020] (Embodiment 2) The configuration of a power transmission device 1A according to a second embodiment will be described with reference to Fig. 2. In the figure, the same components as those of the power transmission device 1 described above are given the same reference numerals and the description thereof will be omitted.

[0021] The power transmission device 1A includes a motor shaft 11, a gear shaft 12, a spacer 13A, a case 14, bearings 15 and 16, and an elastic member 18. Note that the case 14 and the bearing 17 are not shown in FIG.

[0022] The spacer 13A is disposed axially between the motor shaft 11 and the elastic member 18. The spacer 13A is in contact with both the motor shaft 11 and the elastic member 18 in the axial direction.

[0023] The elastic member 18 is disposed between the spacer 13A and the gear shaft 12 in the axial direction. Moreover, the elastic member 18 is disposed between the motor shaft 11 and the gear shaft 12 in the radial direction. Moreover, the elastic member 18 is fixed (restrained) to the gear shaft 12 side, and is not fixed (restrained) to the motor shaft 11 side.

[0024] In this embodiment, the motor shaft 11 is defined as the "restrained shaft", and the surface of the motor shaft 11 with which the spacer 13A contacts is defined as the "restrained shaft-side axial surface". Also, the gear shaft 12 is defined as the "restrained shaft", and the surface of the elastic member 18 with which the spacer 13A contacts is defined as the "restrained shaft-side axial surface".

[0025] As described above, the elastic member 18 is fixed (restrained) to the gear shaft 12 side, but is not fixed (restrained) to the motor shaft 11 side. Therefore, when the spacer 13A thermally expands, the spacer 13A presses the elastic member 18, causing the gear shaft 12 to be pushed out in the axial direction.

[0026] In the power transmission device 1A having such a configuration, for example, when the environmental temperature rises, the spacer 13A thermally expands together with the case 14. That is, when the case 14 thermally expands, the spacer 13A also thermally expands, pushing the gear shaft 12 in the axial direction via the elastic member 18. As a result, the end face 121 of the gear shaft 12 approaches the case 14, suppressing the expansion of the gap Sp. That is, the increase in the gap Sp due to the thermal expansion of the case 14 can be compensated for by the thermal expansion of the spacer 13A.

[0027] In this way, according to the power transmission device 1A of the second embodiment, even when the elastic member 18 is provided, the spacer 13A can reliably close the gap Sp that has expanded due to the thermal expansion of the case 14. Therefore, it is possible to suppress the gear rattle noise.

[0028] (Embodiment 3) The configuration of a power transmission device 1B according to a third embodiment will be described with reference to Fig. 3. In the figure, the same components as those of the power transmission devices 1 and 1A described above are given the same reference numerals and the description thereof will be omitted.

[0029] The power transmission device 1B includes a motor shaft 11, a gear shaft 12, a spacer 13B, a case 14, bearings 15 and 16, an elastic member 18A, and a core material 19. Note that the case 14 and the bearing 17 are omitted from illustration in Fig. 3.

[0030] The spacer 13B is disposed axially between the motor shaft 11 and the core material 19. The spacer 13B is in contact with both the motor shaft 11 and the core material 19 in the axial direction.

[0031] The elastic member 18A is disposed between the motor shaft 11 and the core material 19 in the radial direction. Moreover, the elastic member 18A is not fixed (constrained) to the motor shaft 11. Moreover, the elastic member 18A is fixed to the core material 19.

[0032] The core material 19 is disposed in the radial direction between the elastic member 18A and the gear shaft 12. The core material 19 is fixed (restrained) to the gear shaft 12 side.

[0033] In this embodiment, the motor shaft 11 is defined as the "restrained shaft", and the surface of the motor shaft 11 with which the spacer 13B contacts is defined as the "restrained shaft-side axial surface". Also, the gear shaft 12 is defined as the "restrained shaft", and the surface of the core material 19 with which the spacer 13B contacts is defined as the "restrained shaft-side axial surface".

[0034] As described above, the core material 19 is fixed (restrained) to the gear shaft 12 side, and the elastic member 18A is not fixed (restrained) to the motor shaft 11 side. Therefore, when the spacer 13B thermally expands, the spacer 13B presses the core material 19, and the gear shaft 12 is pushed out in the axial direction.

[0035] In the power transmission device 1B having such a configuration, for example, when the environmental temperature rises, the spacer 13B thermally expands together with the case 14. That is, when the case 14 thermally expands, the spacer 13B also thermally expands, pushing the gear shaft 12 in the axial direction via the core material 19. This brings the end face 121 of the gear shaft 12 closer to the case 14, suppressing the expansion of the gap Sp. That is, the increase in the gap Sp due to the thermal expansion of the case 14 can be compensated for by the thermal expansion of the spacer 13B.

[0036] Thus, according to the power transmission device 1B of the second embodiment, even when the elastic member 18A includes the core material 19 and the core material 19 is constrained, the spacer 13B can be provided to reliably close the gap Sp that has expanded due to the thermal expansion of the case 14. Therefore, the gear rattle noise can be suppressed.

[0037] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0038] 1,1A,1B Power transmission device 11 Motor shaft 12 Gear shaft 121 End face 13,13A,13B Maza 14 cases 15, 16, 17 Bearings 18, 18A Elastic member 19 Core material Sp Gap

Claims

[Claim 1] a motor shaft extending in an axial direction; a gear shaft arranged coaxially with the motor shaft and spline-fitted with the motor shaft; a spacer disposed between the motor shaft and the gear shaft; A case supporting the gear shaft; Equipped with The spacer is in axial contact with the motor shaft and the gear shaft, respectively.

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