Rotary drive

Abstract

The present invention relates to a rotary drive device. The rotary drive device (100) comprises: a shaft (S3) having one end (3a) and the other end (3b) in the axial direction, and provided with an oil passage for allowing lubricating oil to flow from the one end (3a) side to the other end (3b) side; a gearbox (14) accommodating the shaft (S3) inside; and a bearing (62b) arranged on the other end (3b) side of the shaft (S3) in the gearbox (14) to support the shaft (S3) rotatably. The shaft (S3) includes an end face (3c) located at the other end (3b) in the axial direction. The gearbox (14) is provided with an opposing face portion that is opposite to the end face (3c) with a gap in the axial direction. A groove portion that generates negative pressure on the other end (3b) side as the shaft (3S) rotates is provided on either the end face (3c) or the opposing face portion.

Description

Technical Field

[0001] The present disclosure relates to a rotation drive device mounted on a transmission. Background Art

[0002] As a conventional rotary drive device, Japanese Patent Application Laid-Open No. 2020-031492 discloses a structure in which a drive shaft having an oil passage inside which lubricating oil can flow is rotatably supported by a bearing in a transmission.

[0003] An oil passage is provided in the drive shaft described in Japanese Patent Gazette No. 2020-031492 for lubricating oil to flow from one end side to the other end side in the axial direction. The drive shaft is generally supported by bearings at one end side and the other end side. In a configuration in which the lubricating oil flows from one end side to the other end side of the drive shaft, after the lubricating oil passes through the drive shaft, the lubricating oil is supplied to the bearing disposed at the other end side of the drive shaft. Therefore, it takes time for the lubricating oil to be supplied to the bearing, and the bearing may be insufficiently lubricated immediately after the operation starts. Summary of the invention

[0004] The present disclosure is completed in view of the above-mentioned problems, and the purpose of the present disclosure is to provide a rotation drive device that can make lubricating oil flow efficiently from one end side to the other end side in the shaft, thereby shortening the time for the lubricating oil to reach the bearing on the other end side of the supporting shaft.

[0005] The rotary drive device based on the present disclosure comprises: a shaft having one end and the other end in the axial direction, and provided with an oil passage for allowing lubricating oil to flow from the one end side to the other end side; a gearbox accommodating the shaft inside; and a bearing arranged on the other end side of the shaft in the gearbox to support the shaft rotatably. The shaft includes an end face located at the other end in the axial direction. The gearbox is provided with an opposing face portion that is opposite to the end face with a gap in the axial direction. A groove portion that generates negative pressure on the other end side as the shaft rotates is provided on either the end face or the opposing face portion.

[0006] According to the above configuration, a groove is provided on the end surface provided at the other end of the shaft or on the opposing surface portion which is opposed to the end surface with a gap, so that when the shaft rotates, air is sent along the groove to the periphery of the other end, and negative pressure is generated on the other end side of the shaft. As a result, the lubricating oil supplied to one end side of the shaft is sucked toward the other end side of the shaft, so that the lubricating oil can flow efficiently in the shaft. As a result, it is possible to suppress the lubricating oil from leaking out from one end side of the shaft to the outside, and shorten the time it takes for the lubricating oil to reach the bearing arranged on the other end side of the shaft.

[0007] In the rotary drive device based on the present disclosure, the gearbox has an opposing wall portion that is opposed to the other end side of the shaft in the axial direction. In this case, an annular portion may be provided on the inner surface of the opposing wall portion in a manner coaxial with the central axis of the shaft, and the opposing surface portion may be composed of an end face of the annular portion that is opposed to the end face side of the shaft in the axial direction.

[0008] According to the above configuration, an annular portion that is spaced apart from the end face of the shaft in the axial direction and faces the end face is provided in the transmission case, thereby enabling the lubricating oil to efficiently flow from one end side to the other end side in the shaft with a simple structure, thereby shortening the time it takes for the lubricating oil to reach the bearing on the other end side of the supporting shaft.

[0009] In the rotation drive device according to the present disclosure, a plurality of the grooves may be provided. In this case, the plurality of grooves may be provided radially with respect to the central axis of the shaft.

[0010] According to the above configuration, the air in the shaft can be more effectively sent out from the other end side to the outside of the shaft.

[0011] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing the configuration of a power transmission device according to an embodiment.

[0013] Figure 2 Yes means Figure 1 A cross-sectional view showing the positional relationship of multiple shafts included in a power transmission device.

[0014] Figure 3 It is a diagram showing a lubrication device provided in the power transmission device according to the embodiment.

[0015] Figure 4 It is a schematic cross-sectional view showing a rotation drive device included in the power transmission device according to the embodiment.

[0016] Figure 5 It is a perspective view showing an annular portion of a transmission provided in the power transmission device according to the embodiment.

[0017] Figure 6 It is a diagram showing the flow of air on the other end side of the shaft in the rotation drive device according to the embodiment.

[0018] Figure 7 This is a schematic cross-sectional view showing how air and lubricating oil flow in the rotary drive device according to the embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that, in the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions are omitted.

[0020] Figure 1 2 is a diagram showing the configuration of a power transmission device according to an embodiment. Figure 1 The power transmission device 12 according to the first embodiment will be described.

[0021] like Figure 1 As shown, the power transmission device 12 is mounted on the vehicle 10. The vehicle 10 is an engine-driven vehicle, and is a hybrid vehicle having a driving motor as a driving force source in addition to the engine. It should be noted that the vehicle 10 may also be an electric vehicle having only an electric motor as a driving force source.

[0022] The power transmission device 12 preferably uses a transverse drive axle such as an FF (front engine / front wheel drive) in which multiple shafts are arranged in the vehicle width direction, but it can also be a FR (front engine / rear wheel drive) type or a 4-wheel drive type power transmission device. The output part of the power transmission device 12 is, for example, a differential device that outputs the driving force transmitted from the driving force source via a gear mechanism to the left and right driving wheels.

[0023] Specifically, the power transmission device 12 includes first to fourth axes S1 to S4 substantially parallel to the vehicle width direction. The first axis S1 is provided with an input shaft 22 connected to the engine 20 as a driving force source, and a single pinion type planetary gear device 24 and a first electric motor MG1 are disposed concentrically with the first axis S1.

[0024] The planetary gear device 24 and the first electric motor MG1 function as an electric differential portion 26. The input shaft 22 is connected to the carrier 24c of the planetary gear device 24 as a differential mechanism, and the first electric motor MG1 is connected to the sun gear 24s. The ring gear 24r is provided with an output gear Ge.

[0025] The first electric motor MG1 is equivalent to a rotating machine for differential control. The first electric motor MG1 is used as an electric motor and a generator. The rotation speed of the sun gear 24s is continuously controlled by regenerative control that functions as a generator, so that the rotation speed of the engine 20 is continuously changed and output from the output gear Ge. In addition, the torque of the first electric motor MG1 is set to 0, and the sun gear 24s is made to idle, thereby preventing the linked rotation of the engine 20. The engine 20 is an internal combustion engine that generates power by burning fuel.

[0026] The second shaft S2 is provided with a reduction gear device 30 having a reduction gear Gr1 and a reduction gear Gr2 at both ends of the shaft 28. The reduction gear Gr1 meshes with the output gear Ge. The reduction gear Gr1 meshes with the motor output gear Gm of the second electric motor MG2 provided on the third shaft S3.

[0027] The second electric motor MG2 is used as an electric motor and a generator. The second electric motor MG2 is controlled to function as an electric motor and is used as a driving force source for traveling (driving) the hybrid vehicle. The second electric motor MG2 corresponds to a traveling electric motor.

[0028] The reduction pinion gear Gr2 meshes with the differential ring gear Gd of the differential device 32 disposed on the fourth shaft S4. The driving force from the engine 20 and the second electric motor MG2 is distributed to the left and right drive shafts 36 via the differential device 32, and transmitted to the left and right drive wheels 38. The differential device 32 corresponds to the output unit, and the differential ring gear Gd corresponds to the input gear.

[0029] The planetary gear device 24 , the output gear Ge, the large reduction gear Gr1 , the small reduction gear Gr2 , the differential ring gear Gd, and the like constitute a gear mechanism.

[0030] Figure 2 Yes means Figure 1 A cross-sectional view showing the positional relationship of multiple shafts included in a power transmission device.

[0031] like Figure 2 As shown, the fourth axis S4 is fixed at the position closest to the lower side of the vehicle among the first to fourth axes S1 to S4, the second axis S2 and the third axis S3 are fixed above the fourth axis S4, and the first axis S1 is fixed at a position obliquely above the front side of the vehicle than the fourth axis S4.

[0032] A catch tank 70 is provided at the upper portion of the box 14. The catch tank 70 is formed with both upper side openings. For example, lubricating oil scraped by the rotation of the differential ring gear Gd flows from the opening of the catch tank 70 and is stored in the catch tank 70. The catch tank 70 forms a third oil reservoir 72.

[0033] The catch tank 70 is provided on the upper side of the first electric motor MG1. It should be noted that the catch tank 70 may also be provided on the upper side of the second electric motor MG2.

[0034] In such a vehicle 10 , a BEV (Battery Electric Vehicle) running mode and an HEV (Hybrid Electric Vehicle) running mode can be executed.

[0035] Specifically, the BEV travel mode is a mode for traveling using the second electric motor MG2 as a driving force source by performing power running control on the second electric motor MG2 while the engine 20 is stopped, and is therefore selected in a low required driving force, ie, low load region.

[0036] The HEV driving mode is a mode in which the first electric motor MG1 generates a reaction force by regenerative control and the engine 20 is used as a driving force source for driving, and is therefore selected in a region where the required driving force is high, i.e., a high load, compared to the BEV driving mode. It should be noted that an engine driving mode in which only the engine 20 is always used as a driving force source may be provided instead of or in addition to the HEV driving mode.

[0037] Figure 3 2 is a diagram showing a lubrication device provided in a power transmission device according to an embodiment. Figure 3 As shown, the lubrication device 40 includes a first oil pump P1 and a second oil pump P2 as suction devices, which are respectively connected to different independent first supply paths 42 and second supply paths 44 to share lubrication for various parts of the power transmission device 12 .

[0038] like Figure 1 As shown, the first oil pump P1 is mechanically rotationally driven by the output portion (differential device 32 ) via a pump drive gear Gp meshing with a differential ring gear Gd. The second oil pump P2 is connected to the input shaft 22 and mechanically rotationally driven by the engine 20 .

[0039] The first oil pump P1 may be rotationally driven by meshing the pump drive gear Gp with the large reduction gear Gr1 , the small reduction gear Gr2 , and the like that rotate in conjunction with the differential ring gear Gd.

[0040] The first oil pump P1 and the second oil pump P2 suck lubricating oil from the oil reservoir 46 provided at the bottom of the tank 14 and output the lubricating oil to the first supply path 42 and the second supply path 44. The oil reservoir 46 is formed by the tank 14 itself. The oil reservoir 46 includes a first oil reservoir 50 divided into a rear side portion in the vehicle front-rear direction by a partition wall 52 and a second oil reservoir 56 divided into a front side portion in the vehicle front-rear direction by a partition wall 52.

[0041] The first oil reservoir 50 is located below the differential device 32. The second oil reservoir 56 is located below the first shaft S1 on which the planetary gear device 24 and the like are arranged. A suction port 58 of the first oil pump P1 is arranged in the first oil reservoir 50. A suction port 60 of the second oil pump P2 is arranged in the second oil reservoir 56. The suction ports 58 and 60 are connected to the first oil pump P1 and the second oil pump P2 respectively via separate suction oil passages that are independently provided.

[0042] The first supply path 42 is connected to the discharge side of the first oil pump P1, and supplies lubricating oil to various parts of the power transmission device 12. Specifically, the first supply path 42 is configured to supply lubricating oil to the bearings 62, gear mechanisms 64 (Ge, Gr1, Gr2, Gd, Gm, Gp, etc.) and the like of various parts of the power transmission device 12, and to supply lubricating oil to the third oil reservoir 72.

[0043] The second supply path 44 connected to the discharge side of the second oil pump P2 supplies the lubricating oil to the input shaft 22, the planetary gear device 24, and the first electric motor MG1 located above the second oil reservoir 56 for cooling. A heat exchanger 66 is provided in the second supply path 44 to cool the lubricating oil and then supply it to the first electric motor MG1 and the second electric motor MG2. Thus, the first electric motor MG1 and the second electric motor MG2 can be cooled. The heat exchanger 66 is, for example, an oil cooler that cools the lubricating oil by heat exchange based on air cooling or water cooling.

[0044] The third oil reservoir 72 is provided above the oil level height Lst at rest. The third oil reservoir 72 is provided above the first oil reservoir 50 and the second oil reservoir 56 .

[0045] The third oil reservoir 72 has a first outflow port 74. When the stored lubricating oil exceeds a predetermined amount, the lubricating oil flows out from the first outflow port 74 to the first oil reservoir 50 due to its own weight.

[0046] The third oil reservoir 72 has a second outflow port 80 on the lower side than the first outflow port 74. Even when the lubricating oil stored in the third oil reservoir 72 is less than a predetermined amount, that is, when it does not exceed the predetermined amount, the second outflow port 80 allows the lubricating oil to continuously flow out to the first oil reservoir 50 due to its own weight without passing through the second oil reservoir 56.

[0047] Figure 4 It is a schematic cross-sectional view showing a rotation drive device included in the power transmission device according to the embodiment.

[0048] like Figure 4 As shown, the rotary drive device 100 of the embodiment includes a case 14 as a transmission case, a third shaft S3 provided in the second electric motor MG2, and bearings 62a, 62b, and 62c.

[0049] The third shaft S3 has one end 3a and the other end 3b in the axial direction. The third shaft S3 is provided with an oil passage 3d through which lubricating oil can flow from the one end 3a side to the other end 3b side. The third shaft S3 has an end surface 3c located on the other end 3b side in the axial direction.

[0050] The third shaft S3 includes a rotor shaft S31 to which the rotor of the second electric motor MG2 is fixedly mounted, and a connecting shaft S32 concentrically connected to the rotor shaft S31 by spline fitting. The outer diameter of the connecting shaft S32 is smaller than the inner diameter of the rotor shaft S31 at the fitting portion with the rotor shaft S31.

[0051] The rotor shaft S31 is arranged on the other end 3b side of the third shaft S3. The connecting shaft S32 is arranged on the one end 3a side of the third shaft S3. The connecting shaft S32 is provided with a motor output gear Gm.

[0052] The third shaft S3 is rotatably supported by bearings 62a, 62b, and 62c in the case 14.

[0053] The bearing 62a is arranged on the one end 3a side of the third shaft S3. The bearing 62b is arranged on the other end 3b side of the third shaft S3. The bearing 62c is arranged substantially in the center of the third shaft S3.

[0054] The case 14 accommodates the third shaft S3 and the bearings 62a, 62b, 62c therein. The case 14 supports the bearings 62a, 62b, 62c.

[0055] The case 14 includes a facing wall portion 141 facing the end surface 3c of the third axis S3 in the axial direction of the third axis S3. An annular portion 142 is provided on an inner surface 141a of the facing wall portion 141.

[0056] The annular portion 142 is arranged coaxially with the central axis of the third axis S3. The central axis of the annular portion 142 and the central axis of the third axis S3 are arranged coaxially. The annular portion 142 has an end face 142c in the axial direction that is opposite to the end face 3c of the third axis S3. The end face 142c is equivalent to an opposite face portion of the box 14 that is arranged in a manner opposite to the end face 3c with a gap in the axial direction. It should be noted that the gap is a gap that can exert a pump effect through the rotation of the third axis S3.

[0057] In the present embodiment, the annular portion 142 is constituted by the box 14 and other members, but the present invention is not limited thereto. The annular portion 142 may constitute a part of the box 14 and be integrally formed with the box 14 .

[0058] Figure 5 It is a perspective view showing an annular portion of a transmission provided in the power transmission device according to the embodiment.

[0059] like Figure 5 As shown, the end surface 142c of the annular portion 142 is provided with a plurality of grooves 143. The plurality of grooves 143 are used to play a pumping role as the third shaft S3 rotates, thereby generating negative pressure on the other end 3b side of the third shaft S3. It should be noted that as long as negative pressure can be generated, the number of grooves 143 can also be odd.

[0060] The plurality of grooves 143 are provided radially with respect to the central axis of the third shaft S3 , so that, as described later, when the third shaft S3 rotates, the air in the third shaft S3 can be more effectively sent out from the other end 3 b side to the outside of the third shaft S3 .

[0061] The groove 143 is arranged to extend from the inner peripheral edge side of the end face 142c toward the outer peripheral edge side. The starting point of the groove 143 may be the inner peripheral edge of the end face 142c, or may be a position away from the inner peripheral edge. Similarly, the end point of the groove 143 may be the outer peripheral edge of the end face 142c, or may be a position away from the outer peripheral edge inwardly. In addition, the groove 143 may be bent toward the outer peripheral edge side, or may be folded.

[0062] Figure 6 1 is a diagram showing the flow of air on the other end side of the shaft in the rotary drive device of the embodiment. Figure 6 is Figure 4 The diagram is a top view of the annular portion 142 and its surroundings as viewed in the direction of arrow VI.

[0063] like Figure 6 As shown, when the third shaft S3 rotates, as shown by the dotted arrow in the figure, the air passes through the plurality of grooves 143 and is discharged from the gap between the end face 142c of the annular portion 142 and the end face 3c of the third shaft S3 to the radially outer side of the third shaft S3. As a result, negative pressure is generated on the other end 3b side of the third shaft S3, and the pressure on the other end 3b side of the third shaft S3 is lower than the pressure on the one end 3a side of the third shaft S3.

[0064] Figure 7 This is a schematic cross-sectional view showing how air and lubricating oil flow in the rotary drive device according to the embodiment.

[0065] When the vehicle 10 starts to drive, the lubricating oil supplied through the first supply path 42 is as follows: Figure 7 As shown by arrow AR1 in FIG. 1 , the oil passage 3d is introduced from one end 3a side of the third shaft S3.

[0066] Generally, a part of the lubricating oil introduced into the oil passage 3d leaks out from the one end 3a to the outside of the third shaft S3 as indicated by arrow AR3, and the rest flows toward the other end 3b as indicated by arrow AR2.

[0067] In this embodiment, as described above, the groove 143 is provided on the end surface 142c as the facing surface, thereby generating negative pressure on the other end 3b side of the third shaft S3 due to the rotation of the third shaft S3. Therefore, as shown by arrow AR5, the air in the third shaft S3 is sucked into the other end 3b side.

[0068] Thus, the lubricating oil supplied to the one end 3a side of the third shaft S3 is sucked toward the other end 3b side of the third shaft S3, so that the lubricating oil can flow efficiently in the third shaft S3. As a result, it is possible to suppress the lubricating oil from leaking out from the one end 3a side of the third shaft S3, and shorten the time it takes for the lubricating oil to reach the bearing 62b disposed on the other end 3b side of the third shaft S3.

[0069] (Other Modifications)

[0070] It should be noted that, in the above-mentioned embodiment, the groove portion 143 is provided on the end surface 142 c of the annular portion 142 , but the present invention is not limited thereto and the groove portion 143 may be provided on the end surface 3 c of the third axis S3 .

[0071] Furthermore, in the above-mentioned embodiment, the case where the annular portion 142 is provided is described by way of example, but the present invention is not limited thereto, and the annular portion 142 may be omitted. In this case, the above-mentioned opposing wall portion 141 may be configured as a thick wall, with a gap that can generate a pumping action, and the inner surface 141a may be directly opposed to the end surface 3c of the third shaft S3. It should be noted that when the annular portion 142 is provided, the lubricating oil can efficiently flow in the third shaft S3 with a simple structure without changing the shape of the box 14, thereby shortening the time it takes for the lubricating oil to reach the bearing on the other end 3b side supporting the third shaft S3.

[0072] In addition, in the above embodiment, the configuration of the rotation drive device 100 is applied to the third shaft S3 of the second electric motor MG2, but is not limited thereto and may also be applied to the first shaft S1 of the first electric motor MG1 or the second shaft S2 of the reduction gear device 30.

[0073] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered as illustrative rather than restrictive in all aspects. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A rotary drive device comprising: A shaft having one end and another end in the axial direction, and provided with an oil passage for allowing lubricating oil to flow from the one end side to the other end side; a gearbox accommodating the shaft therein; and a bearing, arranged in the transmission case at the other end side of the shaft, rotatably supporting the shaft, The shaft includes an end surface located at the other end in the axial direction, The transmission case is provided with an opposing surface portion that is opposed to the end surface with a gap therebetween in the axial direction. A groove portion that generates negative pressure on the other end side as the shaft rotates is provided on one of the end surface and the facing surface portion.

2. The rotary drive device according to claim 1, wherein: The transmission case includes an opposing wall portion opposing the other end side of the shaft in the axial direction. An annular portion is provided on the inner surface of the opposing wall portion so as to be coaxial with the central axis of the shaft. The facing surface portion is constituted by an end surface of the annular portion that faces the end surface side of the shaft in the axial direction.

3. The rotary drive device according to claim 1 or 2, wherein: A plurality of the grooves are provided, The plurality of grooves are provided radially with respect to the central axis of the shaft.

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