JP7481188B2 - Lubrication structure for vehicle power transmission device - Google Patents

Description

The present invention relates to a lubrication structure for a vehicle power transmission device, and in particular to a technology for supplying lubricating oil discharged from an oil pump to an oil passage provided in the axial center of a rotating shaft.

A lubrication structure for a vehicle power transmission device is known, which includes (a) a case, (b) a rotating shaft arranged substantially horizontally in the case, with an oil passage formed at the rotating shaft center and the oil passage opening at one end in the axial direction, and (c) a bearing arranged on the inner periphery of a cylindrical bearing holder provided in the case and rotatably supporting the one end of the rotating shaft, and (d) a lubricating oil discharged from an oil pump is supplied to the oil passage of the rotating shaft. The device described in Patent Document 1 is one example, in which lubricating oil discharged from a first oil pump P1 mechanically driven to rotate by a differential device 32 is supplied to an oil passage provided at the axis of a power transmission shaft 34, which is a rotating shaft. Patent Document 2 also describes a technology in which a baffle plate having a pair of outer and inner cylindrical members is arranged at the opening of an oil passage provided at the axis of the rotating shaft, and the amount of lubricating oil supplied to an oil passage (oil passage 31) of the rotating shaft (shaft 30) is adjusted.
In this specification, "lubrication" does not only refer to the prevention of friction and wear, but also includes the supply of lubricating oil to a rotating machine or the like to cool it.

JP 2019-48549 A JP 2010-216569 A

However, since the technology described in Patent Document 2 increases the number of parts, it is possible to provide an oil hole in the bearing holder, supply the lubricating oil supplied from the oil pump from the oil hole to the shaft end gap between the case and the rotating shaft, and allow the lubricating oil flowing down from the shaft end gap along the inner wall surface of the case to flow into the oil passage of the rotating shaft (not known). In this case, a trough-shaped part with its tip inserted into the oil passage of the rotating shaft is provided in the inner wall surface of the case, which is the center part of the bearing holder, and the lubricating oil flowing down the shaft end gap is received by the trough-shaped part and guided into the oil passage of the rotating shaft. However, when the lubricating oil flowing down from directly above the trough-shaped part is received by the trough-shaped part, it bounces back and jumps out of the trough-shaped part, making it difficult to stably supply the lubricating oil to the oil passage of the rotating shaft. For example, when it is desired to supply a large amount of lubricating oil to the oil passage of the rotating shaft at high vehicle speeds, even if a large amount of lubricating oil is supplied from the oil pump, the amount of lubricating oil jumping out of the trough-shaped part increases, and there is a possibility that the amount of lubricating oil supplied to the oil passage of the rotating shaft will be insufficient.

The present invention was made against the background of the above circumstances, and its purpose is to make it possible to stably supply lubricating oil supplied from an oil pump to the oil passage of a rotating shaft using a simple structure.

In order to achieve the above object, the present invention provides a lubrication structure for a vehicle power transmission device , the vehicle power transmission device comprising: (a) a case; (b) a rotating shaft having a motor output gear that meshes with a reduction gear and that is disposed substantially horizontally within the case, an oil passage formed at the rotation axis and that opens at one axial end of the rotating shaft, the oil passage being connected to a power source for traveling ; (c) a bearing that is disposed by clearance fit on the inner periphery of a cylindrical bearing holder provided in the case and that rotatably supports the one end of the rotating shaft; (d) a lubrication structure for a vehicle power transmission device in which lubricating oil discharged from an oil pump is supplied to the oil passage of the rotating shaft, the vehicle power transmission device comprising: (e) a shaft end gap is provided between an inner wall surface of the case at the inner periphery of the bearing holder and the bearing and the rotating shaft; (f) an oil hole provided in the case continuous with an oil introduction portion provided above the shaft end gap so that the lubricating oil supplied from the oil pump is introduced from the oil introduction portion into the shaft end gap; and (g) and a gutter-shaped portion that is provided on the inner wall surface of the case at the center of the bearing holding portion, protruding from the inner wall surface so that its tip can be inserted into the oil passage of the rotating shaft, and that receives the lubricating oil flowing down the shaft end gap and allows it to flow into the oil passage of the rotating shaft, and (h) the oil introduction portion is provided at a position shifted circumferentially from directly above the rotating shaft center, in a non-load area that is an angular range in which no meshing reaction force occurs due to the meshing of the reduction gear and the motor output gear during power transmission , and an inclined guide is provided on the inner wall surface of the case for receiving the lubricating oil flowing downward from the oil introduction portion and guiding it to the gutter-shaped portion , the guide being arranged in a straight line connecting the oil introduction portion and the gutter-shaped portion .

In such a lubrication structure for a vehicle power transmission device, the lubricating oil supplied from the oil pump is introduced into the shaft end gap from the oil introduction part through an oil hole provided in the case, and the lubricating oil flowing down the shaft end gap flows into the gutter-shaped part and is supplied into the oil passage of the rotating shaft, but the oil introduction part is provided at a position shifted in the circumferential direction from directly above the rotating shaft center, in a non-loaded region that is an angular range in which the meshing reaction force caused by the meshing of the reduction gear and the motor output gear does not act during power transmission , and the lubricating oil flowing down from the oil introduction part is received by an inclined guide provided to connect the oil introduction part and the gutter-shaped part in a straight line and made to flow into the gutter-shaped part. In other words, the lubricating oil flowing down from the oil introduction part is made to flow down obliquely by the inclined guide and made to flow into the gutter-shaped part, so that the speed at which it flows into the gutter-shaped part is slower than when it falls from directly above and is received by the gutter-shaped part, and the lubricating oil flowing into the gutter-shaped part is prevented from bouncing back and jumping out, and the lubricating oil is stably supplied into the oil passage of the rotating shaft. In addition, a portion of the lubricating oil introduced from the oil hole to the oil inlet portion provided in the non-load area flows into the gap between the outer ring of the bearing and the bearing holder, suppressing wear due to sliding rotation of the outer ring which is gap-fitted into the bearing holder.

FIG. 1 is a schematic diagram for explaining an example of a vehicle power transmission device having a lubrication structure of the present invention, and is an exploded view showing a plurality of shafts positioned on a common plane. 2 is a cross-sectional view illustrating a positional relationship between a plurality of shafts of the vehicle power transmission device of FIG. 1. FIG. 3 is a cross-sectional view corresponding to the portion viewed from the arrows III-III in FIG. 4, specifically explaining the support structure of a gear shaft (rotary shaft) disposed on a third axis S3 in the vehicle power transmission device of FIG. 1. 4 is a side view of an inner wall surface of a transaxle case supporting one end of the gear shaft in FIG. 3 as viewed from the axial direction. FIG.

The present invention can be applied to various types of vehicle power transmission devices, such as engine-driven vehicles equipped with an engine (internal combustion engine) as a driving force source, hybrid vehicles equipped with an engine and an electric motor, or electric vehicles that run using an electric motor as a driving force source. The vehicle power transmission device is, for example, a transaxle in which multiple shafts including a rotating shaft are arranged parallel to the vehicle width direction and a differential device that distributes driving force to left and right driving wheels is arranged in a common case, but it may also be a horizontal or vertical transmission that does not have a differential device. It can also be applied to a four-wheel drive vehicle power transmission device. As a bearing that rotatably supports the rotating shaft, a ball bearing is preferably used, but other bearings such as a roller bearing can also be used. In general, one of the inner and outer rings of the bearing is press-fitted (interference fit) and the other is gap-fitted. For example, the inner ring is press-fitted and fixed to the rotating shaft, and the outer ring is gap-fitted to the bearing holder, but the outer ring may be press-fitted and fixed to the bearing holder, and the inner ring may be gap-fitted to the rotating shaft.

The oil pump may be a mechanical oil pump that is mechanically rotated by a specific rotating member of the engine or the power transmission path, or an electric oil pump that is rotated at any timing by a dedicated electric motor. As an oil supply passage that supplies the lubricating oil discharged from the oil pump to a specific lubrication part, for example, an oil supply pipe configured separately from the case is preferably used, but the oil supply passage can also be provided inside the side wall of the case or in the shaft member. At least a part of the lubricating oil discharged from the oil pump is introduced into the shaft end gap from the oil introduction part through the oil hole provided in the case. The oil hole is provided, for example, so as to penetrate from the outer peripheral surface to the inner peripheral surface of the bearing holder, and the lubricating oil is supplied from the opening on the outer peripheral surface side and is made to flow into the shaft end gap from the oil introduction part, which is an opening on the inner peripheral surface side. The opening position on the outer peripheral surface side of the oil hole may be within the accommodation space in which the rotating shaft is arranged, or may be outside the accommodation space. The opening on the outer circumferential surface side can be directly connected to an oil supply pipe, for example, or an oil receiving section can be provided to receive the lubricating oil discharged from the supply oil passage such as the oil supply pipe and allow it to flow into the oil hole. The position of the opening on the outer circumferential surface side, i.e., the position of the oil receiving section, etc., is provided at a position shifted in the circumferential direction from directly above the rotation axis, as with the oil introduction section, for example, but the oil receiving section, etc. may be provided directly above the rotation axis, and the oil hole may be provided at an angle in the circumferential direction around the rotation axis.

The oil introduction section is provided at a position shifted in the circumferential direction from directly above the rotation axis, and the angle of this shift is appropriate to be 20° or more, and preferably 30° or more, in order to suppress the flow rate when the lubricating oil flows from the inclined guide into the trough-shaped section. Also, if the angle of shift is too large, the lubricating oil may splash when it is received by the inclined guide, so it is appropriate to set it at 70° or less, and preferably 60° or less. In other words, the angle of shift from directly above the rotation axis in the circumferential direction is appropriate to be in the range of 20° to 70°, and preferably in the range of about 30° to 60°. This oil introduction section may be, for example, the opening of the oil hole on the inner peripheral surface side of the bearing holder, but if a circular ring-shaped pedestal for positioning the outer ring of the bearing is provided on the inner peripheral side of the bearing holder and an axial end gap is provided on the inner peripheral side of the pedestal, the oil introduction section may be provided by cutting out a part of the pedestal. The inclined guide may be, for example, a flat plate shape that guides the lubricating oil linearly to the trough-shaped section, but various forms are possible, such as a concave curved plate shape that is curved concavely downward. An inclined guide with an L-shaped cross section can be used so that a groove is formed between the inner wall surface of the case. The gutter-shaped portion can be U-shaped or semicircular with an upward opening in cross section to allow the lubricating oil to flow in from the inclined guide, but it can also be cylindrical or other tubular except for the part where the lubricating oil flows in from the inclined guide.

The following describes in detail the embodiments of the present invention with reference to the drawings. Note that in the following embodiments, the drawings have been simplified or modified as appropriate for the purpose of explanation, and the dimensional ratios and shapes of each part are not necessarily drawn accurately.

Figure 1 is a schematic diagram of a vehicle power transmission device 10 having a lubrication structure of the present invention, which includes a power transmission mechanism 12. Figure 1 is an exploded view showing the multiple shafts constituting the power transmission mechanism 12 in a common plane, and Figure 2 is a cross-sectional view showing the positional relationship of the multiple shafts. The vehicle power transmission device 10 is a transaxle for a transverse hybrid vehicle such as an FF vehicle in which multiple shafts are arranged along the vehicle width direction, and includes a first axis S1 to a fourth axis S4 that are approximately parallel to the vehicle width direction, i.e., approximately horizontal. An input shaft 22 connected to the engine 16 via a damper device 18 is provided on the first axis S1, and a single-pinion planetary gear device 24 and a first motor generator MG1 are arranged concentrically with the first axis S1. The planetary gear set 24 and the first motor generator MG1 function as an electric differential unit 26, with the input shaft 22 connected to the carrier 24c of the planetary gear set 24, which is a differential mechanism, the rotor shaft 28 of the first motor generator MG1 connected to the sun gear 24s, and the engine output gear Ge provided on the ring gear 24r. The sun gear 24s and the ring gear 24r are engaged with a plurality of pinions 24p rotatably arranged on the carrier 24c.

The first motor generator MG1 is used alternatively as an electric motor or a generator and corresponds to a differential control rotating machine. The rotation speed of the sun gear 24s is continuously controlled by regenerative control or the like that functions as a generator, and the rotation speed of the engine 16 is continuously changed and output from the engine output gear Ge. In addition, the torque of the first motor generator MG1 is set to 0 and the sun gear 24s is rotated idly, cutting off the output from the engine 16 and preventing the engine 16 from rotating together during motor running or coasting. The engine 16 is an internal combustion engine such as a gasoline engine or a diesel engine that generates power by burning fuel, and is used as a driving force source for running. The input shaft 22 is inserted through the axis of the first motor generator MG1 and connected to the second oil pump P2, and the second oil pump P2 is mechanically rotated and driven by the engine 16.

A countershaft 36 provided with a reduction gear Gr1 and a reduction small gear Gr2 is rotatably arranged on the second axis S2, and the reduction gear Gr1 is meshed with the engine output gear Ge. The reduction gear Gr1 is also meshed with a motor output gear Gm arranged on the third axis S3. The motor output gear Gm is provided on a gear shaft 42, which is connected to a rotor shaft 44 of a second motor generator MG2 arranged concentrically with the third axis S3 via a spline engagement portion 46 so that power can be transmitted. The second motor generator MG2 is used alternatively as an electric motor and a generator, and is used as a driving force source for traveling by being power-controlled to function as an electric motor. This second motor generator MG2 corresponds to a traveling rotating machine. The vehicle power transmission device 10 is a dual-shaft hybrid vehicle power transmission device in which the second motor generator MG2 is disposed on a third axis S3 that is different from the first axis S1 on which the engine 16 and the electric differential 26 are disposed.

The reduction gear Gr2 is meshed with the differential ring gear Gd of the differential device 48 arranged on the fourth axis S4, and the driving force from the engine 16 and the second motor generator MG2 is distributed to the left and right drive shafts 52 via the differential device 48 and transmitted to the left and right drive wheels 54. As is clear from FIG. 2, the fourth axis S4 is set at the position furthest below the first axis S1 to the fourth axis S4, the second axis S2 and the third axis S3 are set at positions above the fourth axis S4, and the first axis S1 is set at a position diagonally above the fourth axis S4 and toward the front of the vehicle. More specifically, the fourth axis S4 is set approximately directly below the third axis S3.

The differential ring gear Gd is also meshed with the pump drive gear Gp, and the first oil pump P1 is mechanically rotated in conjunction with the differential ring gear Gd, in other words, in conjunction with the drive wheels 54. In other words, the first oil pump P1 is a mechanical oil pump that discharges lubricating oil at a discharge rate corresponding to the vehicle speed V by being rotated in mesh with the differential ring gear Gd, which is an output rotating member, and the discharge rate increases as the vehicle speed V increases. This first oil pump P1 can also be rotated by meshing the pump drive gear Gp with other output rotating members such as the reduction large gear Gr1 and the reduction small gear Gr2 that rotate in conjunction with the differential ring gear Gd.

The vehicle power transmission device 10 includes a transaxle case 60 that is fixed integrally to the engine 16 and supported by the vehicle body via brackets or the like. The transaxle case 60 is composed of three case members, a front case member 62, an intermediate case member 64, and a rear cover 66, and is joined integrally to each other by fastening with a number of fastening bolts while abutting portions such as flanges provided at the axial ends of each case member are abutted against each other. The front case member 62 has an opening that opens toward the engine 16 and is fixed integrally to the engine 16, and a first accommodation space 72 that accommodates the damper device 18 is formed between the front case member 62 and the engine 16. The intermediate case member 64 is integrally provided with a cylindrical outer cylinder 74 and a partition wall 76 that is provided so as to extend from the outer cylinder 74 toward the inner periphery and is oriented substantially perpendicular to the first axis S1 to the fourth axis S4. Between the front case member 62 and the partition wall 76, a second accommodation space 78 is formed to accommodate the electric differential unit 26, the countershaft 36, the gear shaft 42, the differential device 48, and the like. The front case member 62 and the partition wall 76 are provided with support parts that rotatably support the engine output gear Ge, the countershaft 36, the gear shaft 42, the differential device 48, and the like via bearings. In addition, between the rear cover 66 and the partition wall 76, a third accommodation space 80 is formed to accommodate the first motor generator MG1 and the second motor generator MG2. The rear cover 66 and the partition wall 76 are provided with support parts that rotatably support the rotor shafts 28, 44 via bearings.

Figure 3 is a cross-sectional view specifically explaining the support structure of the gear shaft 42 arranged on the third axis S3. The end of the gear shaft 42 on the second motor generator MG2 side is made smaller in diameter than the rotor shaft 44, is fitted into the cylinder of the rotor shaft 44, and is connected to be able to transmit power via a spline fitting portion 46. The rotor shaft 44 is supported by the transaxle case 60 rotatably around the third axis S3 via a pair of first bearings 92a, 92b (see Figure 1). The first bearings 92a and 92b are arranged on both sides of the rotor of the second motor generator MG2 in the axial direction of the rotor shaft 44. The gear shaft 42 is supported by the transaxle case 60 rotatably around the third axis S3 via a pair of second bearings 96a, 96b. The second bearings 96a and 96b are arranged on both sides of the motor output gear Gm in the axial direction of the gear shaft 42. The gear shaft 42 functions as a drive shaft that transmits the power of the second motor generator MG2 to the countershaft 36 to rotate and drive the drive wheels 54, and also receives the power of the engine 16 and other signals from the countershaft 36 via the motor output gear Gm. The gear shaft 42 also receives reverse input rotation (driven rotation) from the drive wheels 54 via the differential device 48 and the countershaft 36 during coasting, etc.

The second bearings 96a, 96b are both ball bearings, and are arranged and held inside cylindrical second bearing holders 106a, 106b that are provided as supports on the transaxle case 60. The second bearing holder 106a is integrally provided on the partition wall 76 of the intermediate case member 64 concentrically with the third axis S3, and the second bearing holder 106b is integrally provided on the front case member 62 concentrically with the third axis S3. In this embodiment, the inner rings 108a, 108b of the second bearings 96a, 96b are press-fitted and fixed to the gear shaft 42, and the outer rings 110a, 110b are clearance-fitted into the second bearing holders 106a, 106b.

The first oil pump P1 and the second oil pump P2 suck lubricating oil 122 from an oil reservoir 120 (see FIG. 2) provided at the bottom of the transaxle case 60 and discharge the lubricating oil 122 into an oil supply passage provided independently, thereby sharing and lubricating each part of the power transmission mechanism 12. In this embodiment, the lubricating oil 122 discharged from the first oil pump P1 is supplied to a plurality of lubrication parts by an oil supply pipe 124 provided as a first oil supply passage, and a part of it is discharged downward from a nozzle 126 provided at an upper position of the gear shaft 42 as shown in FIG. 3, and is supplied to an oil passage 128 provided through the rotation axis of the gear shaft 42. That is, the vehicle power transmission device 10 is provided with a lubrication structure 130 that introduces the lubricating oil 122 discharged downward from the nozzle 126 into the oil passage 128 from the right end of FIG. 3 supported by the bearing 96b, which is one end of the gear shaft 42. The lubricating oil 122 supplied into the oil passage 128 is supplied to the rotor shaft 44 side and is used for lubricating the first bearings 92a, 92b and the second bearing 96a, or for cooling the rotor of the second motor generator MG2. If necessary, a radial hole is provided at the axial center position of the gear shaft 42 or the rotor shaft 44, and the lubricating oil 122 supplied into the oil passage 128 may be made to flow out from the radial hole and used to lubricate a predetermined lubrication portion. In this embodiment, the transaxle case 60 is the case, the gear shaft 42 is the rotating shaft arranged approximately horizontally in the case, the second bearing holder 106b is the bearing holder, the second bearing 96b is the bearing that rotatably supports one end of the rotating shaft, and the first oil pump P1 is the oil pump that supplies the lubricating oil 122 to the oil passage 128 of the rotating shaft. The third axis S3 corresponds to the rotation axis of the gear shaft 42, which is the rotating shaft.

The lubrication structure 130 will be described in detail with reference to Figures 3 and 4. Figure 4 is a side view of the inner wall surface 62f of the front case member 62 supporting one end of the gear shaft 42, as viewed from the axial direction of the gear shaft 42, and Figure 3 is a cross-sectional view taken along the III-III arrow portion in Figure 4, i.e., along the flow path of the lubricating oil 122. In these figures, an oil receiving portion 132 that receives the lubricating oil 122 discharged from the nozzle 126 is provided on the outer periphery side of the second bearing holder 106b provided on the front case member 62 and above the third axis S3. The oil receiving portion 132 opens upward and has a U-shaped or V-shaped cross section whose width dimension becomes wider as it goes upward, and is provided integrally with the front case member 62 so as to protrude from the inner wall surface 62f along the second bearing holder 106b. As a result, the lubricating oil 122 discharged downward from the oil supply pipe 124 is properly received by the oil receiving portion 132 as shown by the arrow A in FIG. 4. The tip side of this oil receiving portion 132 (the left side in FIG. 3) is open, but if necessary, a side wall or the like can be provided to limit the outflow of the lubricating oil 122. The oil receiving portion 132 can also be constructed separately from the front case member 62 and attached later.

An oil hole 134 is provided at the bottom of the oil receiving portion 132 at the end on the inner wall surface 62f side so as to penetrate from the outer surface to the inner surface of the cylindrical second bearing holding portion 106b. A ring-shaped seat 138 that positions the outer ring 110b via a shim 136 is provided on the inner wall surface 62f of the front case member 62 on the inner side of the second bearing holding portion 106b, and a part of the seat 138 is cut out to provide an oil introduction portion 140, and the oil hole 134 is provided at an incline in the axial direction so as to reach the oil introduction portion 140. As a result, the lubricating oil 122 received by the oil receiving portion 132 is made to flow down through the oil hole 134 to the oil introduction portion 140 on the rear side of the outer ring 110b of the bearing 96b, and further through the oil introduction portion 140 to the inner side of the seat 138. An axial end gap 142 is provided on the inner periphery of the base 138 between the inner ring 108b and the end face of the gear shaft 42 and the inner wall surface 62f, and the lubricating oil 122 that flows down from the oil introduction part 140 flows into this axial end gap 142.

Here, the oil introduction section 140 is provided at a position shifted in the circumferential direction from directly above the third axis S3 around the third axis S3. Specifically, in FIG. 4, it is provided in an angular range of 45° to 60° from directly above the third axis S3 in the clockwise direction. In addition, a load (meshing reaction force) is applied to the gear shaft 42 in a direction perpendicular to the axis during the transmission of driving and driven power due to the meshing of the motor output gear Gm and the reduction gear Gr1, but in this embodiment, the oil introduction section 140 is provided within the range of the non-load area Φ1 (see FIG. 2), which is an angular range in which this load does not act. Therefore, a portion of the lubricating oil 122 supplied from the oil hole 134 to the oil introduction section 140 flows into the gap between the outer ring 110b and the second bearing holder 106b, and wear due to sliding rotation of the outer ring 110b that is gap-fitted in the second bearing holder 106b is suppressed. In this embodiment, as is clear from Fig. 4, the oil receiving portion 132 is also provided at a position shifted clockwise from directly above the third axis S3 in correspondence with the oil inlet 140, and in the side view of Fig. 4, the oil receiving portion 132 is provided directly above the oil inlet 140, and the nozzle 126 of the oil supply pipe 124 is disposed directly above it. Note that Φ2 in Fig. 2 is the angle range (load area) in which a load is applied to the gear shaft 42 during the transmission of driving or driven power.

Meanwhile, part of the lubricating oil 122 that flows down from the oil introduction section 140 into the shaft end gap 142 flows between the outer ring 110b and the inner ring 108b and is used to lubricate the bearing 96b, which includes balls, and the lubricating oil 122 that flows out from the bearing 96b to the left in FIG. 3 flows down near the fourth axis S4 as shown by arrow C in FIG. 2 and is used to lubricate the differential device 48 and the bearings of the differential case, which are arranged on the fourth axis S4. Part of the lubricating oil 122 that flows out or splashes from the oil receiving section 132 to the outside is also caused to flow down near the fourth axis S4 and is used to lubricate the differential device 48, etc.

A gutter-shaped portion 146 is integrally provided on the inner wall surface 62f of the front case member 62 at the center of the second bearing holder 106b, protruding vertically from the inner wall surface 62f, i.e., parallel to the third axis S3, so that the tip of the gutter-shaped portion 146 can be inserted into the oil passage 128 of the gear shaft 42. A flat inclined guide 144 is integrally provided on the inner wall surface 62f of the front case member 62, on the inner peripheral side of the base 138, so as to connect the lower end of the oil introduction portion 140 and the gutter-shaped portion 146 in a straight line, protruding vertically from the inner wall surface 62f. As a result, the lubricating oil 122 flowing down from the oil introduction portion 140 along the inner wall surface 62f is received by the inclined guide 144, and is made to flow down on the inclined guide 144 obliquely toward the third axis S3 direction as shown by the arrow B in Fig. 4, and is made to flow into the gutter-shaped portion 146, and is supplied to the oil passage 128 of the gear shaft 42 by flowing in the axial direction inside the gutter-shaped portion 146. The gutter-shaped portion 146 has a U-shaped or semicircular cross section that opens upward, and the inclination angle of the inclined guide 144 is about 30°, so that the lubricating oil 122 received by the inclined guide 144 is made to smoothly flow into the gutter-shaped portion 146. The lubricating oil 122 leaking or scattering from the inclined guide 144 or the gutter-shaped portion 146 is used to lubricate the bearing 96b, and is made to flow down near the fourth axis S4 to lubricate the differential device 48, etc. The inclined guide 144 and gutter portion 146 can also be constructed separately from the front case member 62 and attached later.

Thus, in the lubrication structure 130 of the vehicle power transmission device 10 of this embodiment, the lubricating oil 122 supplied from the first oil pump P1 through the oil supply pipe 124 is received by the oil receiving portion 132 and introduced into the shaft end gap 142 from the oil introduction portion 140 via the oil hole 134 provided in the second bearing retaining portion 106b. The lubricating oil 122 flowing down the shaft end gap 142 flows into the gutter-shaped portion 146 and is supplied into the oil passage 128 of the gear shaft 42. The oil introduction portion 140 is provided at a position shifted circumferentially from directly above the third axis S3, and the lubricating oil 122 flowing down from the oil introduction portion 140 is received by the inclined guide 144 and is caused to flow into the gutter-shaped portion 146. That is, the lubricating oil 122 flowing down from the oil introduction portion 140 is made to flow diagonally down by the inclined guide 144 and into the gutter-shaped portion 146, so that the speed at which the lubricating oil 122 flows into the gutter-shaped portion 146 is slower than when the lubricating oil 122 falls from directly above and is received by the gutter-shaped portion 146. This prevents the lubricating oil 122 that flows into the gutter-shaped portion 146 from bouncing back and flying out, and ensures that the lubricating oil 122 is stably supplied into the oil passage 128 of the gear shaft 42. As a result, even if a large amount of lubricating oil 122 is supplied to the shaft end gap portion 142, for example, at high vehicle speeds, the lubricating oil 122 is appropriately supplied into the oil passage 128 of the gear shaft 42, and the first bearings 92a, 92b and the second bearing 96a are lubricated, or the rotor of the second motor generator MG2 is cooled appropriately.

In addition, some of the lubricating oil 122 that flows down from the oil introduction section 140 into the shaft end gap section 142 flows into the bearing 96b and is used to lubricate the bearing 96b, which includes the balls, and the lubricating oil 122 that flows out of the bearing 96b flows down near the fourth axis S4 and is used to lubricate the differential device 48, etc., so that the bearing 96b, the differential device 48, etc. are appropriately lubricated.

In addition, the oil introduction section 140 is located around the third axis S3, which is the rotational axis of the gear shaft 42, within the non-load region Φ1 where no load acts during the transmission of driving and driven power. Therefore, a portion of the lubricating oil 122 supplied from the oil hole 134 to the oil introduction section 140 flows into the gap between the outer ring 110b and the second bearing holder 106b, suppressing wear due to sliding rotation of the outer ring 110b, etc.

In addition, for example, if the oil introduction section 140 is provided directly above the gutter-shaped section 146 and the lubricating oil 122 falls directly downward from the oil introduction section 140 and is received by the gutter-shaped section 146, the lubricating oil 122 may bounce back and jump out of the gutter-shaped section 146, resulting in a shortage of lubricating oil supplied to the oil passage 128 of the gear shaft 42 and an excess of lubricating oil supplied to the bearing 96b, etc., which may cause aggravation of the churning loss. However, according to this embodiment, the lubricating oil 122 is appropriately supplied to the oil passage 128, and the aggravation of the churning loss due to the excessive supply of the lubricating oil 122 to the bearing 96b, etc. is suppressed. In other words, the position and size of the oil introduction section 140, the axial dimension of the shaft end gap 142, the inclination angle and protruding dimension of the inclined guide 144, etc. are appropriately set by experiments, simulations, etc. so that the lubricating oil 122 supplied to the shaft end gap 142 is appropriately distributed to both the oil passage 128 of the gear shaft 42 and the bearing 96b.

The above describes in detail an embodiment of the present invention based on the drawings, but this is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

10: Vehicle power transmission device 42: Gear shaft (rotating shaft) 60: Transaxle case (case) 62f: Inner wall surface 96b: Second bearing (bearing) 106b: Second bearing holder (bearing holder) 122: Lubricating oil 128: Oil passage 130: Lubrication structure 134: Oil hole 140: Oil introduction part 142: Shaft end gap 144: Inclined guide 146: Gutter-shaped part P1: First oil pump (oil pump) S3: Third axis (rotating axis)

Claims (1)

Case and
a rotating shaft having a motor output gear that meshes with the reduction gear and disposed substantially horizontally within the case, an oil passage formed at the center of the rotating shaft, the oil passage opening at one end in the axial direction, and connected to a power source for traveling;
a bearing that is disposed by clearance fit on an inner peripheral side of a cylindrical bearing holder provided in the case and rotatably supports the one end of the rotating shaft;
In a lubrication structure for a power transmission device for a vehicle, lubricating oil discharged from an oil pump is supplied to the oil passage of the rotating shaft,
a shaft end gap is provided between an inner wall surface of the case at an inner circumferential portion of the bearing holder, and the bearing and the rotating shaft,
an oil hole provided in the case continuous with an oil inlet portion provided above the shaft end gap so that lubricating oil supplied from the oil pump is introduced into the shaft end gap from the oil inlet portion;
a trough-shaped portion provided on the inner wall surface of the case at a central portion of the bearing holder, the trough-shaped portion protruding from the inner wall surface so that a tip end of the trough is inserted into the oil passage of the rotating shaft, the trough-shaped portion receiving the lubricating oil flowing down the shaft end gap and causing the lubricating oil to flow into the oil passage of the rotating shaft;
the oil inlet portion is provided at a position shifted circumferentially from directly above the rotation axis, in a non-load region which is an angular range in which no meshing reaction force occurs due to meshing between the reduction gear and the motor output gear during power transmission , and an inclined guide is provided on the inner wall surface of the case for receiving the lubricating oil flowing downward from the oil inlet portion and guiding it to the gutter-shaped portion , the inclined guide connecting the oil inlet portion and the gutter-shaped portion in a straight line .

Images