Lubrication system for a vehicle drive system

Abstract

Lubrication system for a vehicle drive system (10), wherein the lubrication system comprises: a case (20), an electric motor (11) which is arranged inside the housing (20), a countershaft (13) rotatably connected to a drive output shaft (18) of the vehicle drive system (10), wherein the countershaft (13) is mounted inside the housing (20) parallel to an output shaft (12) of the electric motor (11), a pair of reduction gears (14) provided between the output shaft (12) of the electric motor (11) and the countershaft (13), a collection container (32) which receives part of the lubricating oil which is collected at a bottom in the housing (20) and supplied to a lubricated area as a result of the lubricating oil being carried along by the reduction gear pair (14), a partition (20a1) that separates an interior of the housing (20) into a wheel chamber (20L) and a motor chamber (20M), wherein the reduction gear pair (14) is accommodated in the wheel chamber (20L) and the electric motor (11) is accommodated in the motor chamber (20M), a bearing (24) which is provided on a bearing support area (41) of the partition wall (20a1) overlapping with a side area of ​​a large-diameter wheel (23) of the reduction gear pair (14) in an axial direction, wherein the bearing (24) supports the countershaft (13), an oil passage (33) provided in the wheel chamber (20L), wherein the oil passage (33) carries lubricating oil, which is carried by the large diameter wheel (23), to the collection container (32), and a connecting hole (44) provided in the partition (20a1), wherein the connecting hole (44) creates a connection between the oil passage (33) and the motor chamber (20M), in which Lubricating oil supplied to the motor chamber (20M) via the connecting hole (44) is supplied to the bearing (24).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The invention relates to a lubricating structure for a vehicle drive system, and more particularly, to a lubricating structure for a two-axle (dual-axle) vehicle drive system that reduces stirring resistance of a reduction gear during vehicle movement by driving a drive output shaft to rotate by transmitting torque from an electric motor via the reduction gear, scooping lubricating oil received at a bottom in a housing of the vehicle drive system and supplied to a lubricated portion with the reduction gear, and collecting a portion of the lubricating oil in a sump. 2. Description of the state of the art

[0002] A lubrication assembly for a two-axle vehicle drive system is known (see, for example, JP 2010 - 223 376 A). The lubrication assembly includes a pair of reduction gears inside a housing of the vehicle drive system. The pair of reduction gears is provided between an output shaft of an electric motor and a countershaft (counter shaft) parallel to the output shaft. The lubrication assembly reduces the stirring or scooping resistance of a reduction gear during vehicle movement by entraining lubricating oil, which is housed at a bottom in the housing and supplied to a lubricated area, with the pair of reduction gears and collecting a portion of the lubricating oil in a collecting container.

[0003] Further lubrication structures are disclosed in DE 11 2010 001 550 T5, DE 11 2011 100 712 T5 and US 2008 / 0 128 208 A1. SUMMARY OF THE INVENTION

[0004] However, in the two-axle vehicle drive system described above, if a partition wall separating the interior of the housing into a wheel chamber housing the reduction gear pair and a motor chamber housing an electric motor is provided to improve the entrainment effect of lubricating oil with the reduction gear pair, and a bearing supporting the countershaft is provided on the partition wall overlapping a side portion of a large-diameter gear of the reduction gear pair to reduce the axial size of the countershaft, in this structure, it is difficult to cause the lubricating oil to reach the bearing supporting the countershaft by entrainment of the lubricating oil using the rotation of the reduction gear pair. Therefore, it is difficult to lubricate the bearing supporting the countershaft.

[0005] The invention provides a lubrication assembly for a vehicle drive system capable of lubricating a bearing supporting a countershaft by entraining lubricating oil with a pair of reduction gears.

[0006] One aspect of the invention provides a lubricating structure for a vehicle drive system. The lubricating structure includes: a housing, an electric motor disposed inside the housing, a countershaft rotatably connected to a drive output shaft of the vehicle drive system, the countershaft being supported inside the housing parallel to an output shaft of the electric motor, a reduction gear pair provided between the output shaft of the electric motor and the countershaft, a receiver for receiving a portion of lubricating oil received at a bottom in the housing and supplied to a lubricated area as a result of entrainment (scooping) of the lubricating oil by the reduction gear pair, and a partition wall separating an interior of the housing into a wheel chamber and a motor chamber.separated, wherein the reduction gear pair is housed in the wheel chamber and the electric motor is housed in the motor chamber, a bearing provided at a bearing support portion of the partition wall overlapping with a side portion of a large-diameter gear of the reduction gear pair in an axial direction, the bearing supporting the countershaft, an oil passage provided in the wheel chamber, the oil passage leading lubricating oil, which is (was) carried from the large-diameter gear to the receiver, to a receiver, and a communication hole provided in the partition wall, the communication hole establishing communication between the oil passage and the motor chamber. The lubricating oil supplied into the motor chamber via the communication hole is supplied to the bearing.

[0007] According to the above configuration, the connecting hole that provides communication between the oil passage and the motor chamber is provided in the partition wall, and lubricating oil supplied into the motor chamber via the connecting hole is supplied to the bearing. Therefore, lubricating oil carried by the large-diameter wheel is allowed to be supplied from the wheel chamber to the motor chamber via the connecting hole, making it possible to lubricate the bearing using the lubricating oil supplied into the motor chamber.

[0008] In the above aspect, the oil passage may have an opening end (open end) from which the lubricating oil entrained by rotation of the large-diameter wheel enters, a resolver that detects rotation of the electric motor may be provided in the motor chamber, the oil passage may have a bulged portion for disposing the resolver on a radially inner side of the bulged portion, and the communication hole may be provided on the opening end side with respect to the bulged portion.

[0009] According to the above configuration, the communication hole is provided at a position where entrained lubricating oil tends to accumulate in the oil passage, so that it is possible to reliably supply lubricating oil into the motor chamber via the communication hole.

[0010] In the above aspect, a projecting portion may be positioned on a radially outer side of the resolver and may be provided on the motor chamber side in the partition wall. The bearing support portion may include a projecting portion, a closed-end bearing hole (front-end closed bearing hole), and a snap ring mounting cutout (circlip mounting cutout), wherein the projecting portion may project into the motor chamber. The closed-end bearing hole may be open to the wheel chamber, adapted to, and supporting the bearing. The snap ring mounting cutout may be provided in the projecting portion open to the motor chamber for holding a snap ring (circlip) for securing the bearing in the bearing hole.and the lubricating oil supplied into the motor chamber via the connecting hole can flow on an outer periphery of the projecting portion and can be supplied to the bearing via the retaining ring mounting cutout.,

[0011] According to the above configuration, a faucet portion boss used for centering the resolver is allowed to be used as the protruding portion, and it is possible to supply lubricating oil supplied into the motor chamber via the communication hole to the bearing by using the snap ring mounting cutout required for fixing the bearing to the bearing support portion, so that it is not necessary to provide additional components.

[0012] In the above aspect, an oil guide rib that guides the lubricating oil from the communication hole to the projecting portion may be provided on the partition wall.

[0013] With the above configuration, the guidance of lubricating oil from the connecting hole to the protruding portion is reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the attached drawings, in which like reference numerals denote similar elements, and wherein: Fig. 1 is a schematic diagram illustrating the schematic configuration of a rear axle of a vehicle to which the invention is applied, Fig. 2 is a front view showing a side of a first portion of a split housing (first split housing portion) of a rear axle housing according to an embodiment of the invention, which is a mating surface for a partition member, Fig. 3 is a front view showing a side of the first split housing portion of the rear axle housing according to the embodiment of the invention, which is a mating surface for a third split housing portion (third split housing portion). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] An embodiment of the invention will be described in more detail with reference to the accompanying drawings. Like reference numerals designate like or corresponding components in the drawings, to which reference is made below.

[0016] Fig. 1 is a schematic diagram showing the configuration of a rear axle 10, which is a vehicle drive system to which the lubrication structure for a vehicle drive system according to the invention is applied, in an electric four-wheel drive vehicle. The rear axle 10 is a two-axle electric vehicle drive system. The rear axle 10 includes an electric motor 11 as a drive source, a first reduction gear pair 14 (which is an example of a reduction gear pair), a second reduction gear pair 16, and a differential gear unit 19 inside a rear axle housing (transaxle housing) 20. The first reduction gear pair 14 is provided between an output shaft 12 of the electric motor 11 and a countershaft (counter shaft) 13 parallel to the output shaft 12.The second reduction gear pair 16 is provided between the countershaft 13 and a differential case 15 parallel to the countershaft 13 and concentric with the electric motor 11. The differential gear unit 19 includes a differential gear (differential mechanism) 17 provided inside the differential case 15. The differential gear unit 19 drives a rear wheel-side drive axle pair 18 (each being an example of a drive output shaft) to rotate using the torque transmitted from the electric motor 11 via the first reduction gear pair 14 and the second reduction gear pair 16.

[0017] A rotor 11a of the electric motor 11 is connected to the center portion of the output shaft 12. A pair of bearings 21 are mounted at both ends of the output shaft 12. Thus, the output shaft 12 is rotatably supported by the rear axle housing 20 via the pair of bearings 21. A stator coil unit 11b is provided around the rotor 11a and fixed to the rear axle housing 20.

[0018] The first reduction gear pair 14 includes a small-diameter counter drive gear 22 and a large-diameter counter driven gear 23 (which is an example of a large-diameter gear). The counter drive gear 22 is integrally fixed (connected) to the distal end side of one end of the output shaft 12. The counter driven gear 23 is integrally fixed to one end side of the countershaft 13 in a state where the counter driven gear 23 meshes (engages) with the counter drive gear 22. A pair of bearings 24 are mounted on both ends of the countershaft 13, respectively. The countershaft 13 is rotatably supported by the rear axle housing 20 via the pair of bearings 24 (each being an example of a bearing that supports a countershaft).

[0019] The second reduction gear pair 16 is arranged to be offset in the axial direction with respect to the first reduction gear pair 14. The second reduction gear pair 16 includes a small-diameter final drive gear 25 and a large-diameter final driven gear 26. The final drive gear 25 is integrally connected (fixed) to the other end of the countershaft 13. The final driven gear 26 is arranged to be offset from the countershaft drive gear 22 in the axial direction of the output shaft 12. The final driven gear 26 is mounted on the outer peripheral portion of the differential case 15 and integrally fixed in a state where the final driven gear 26 meshes (engages) with the final drive gear 25.

[0020] A pair of bearings 27 is mounted on the outer peripheries of the two axial ends of the differential case 15. Therefore, the differential case 15 and the final drive gear 26, which is integrally fixed to the differential case 15, are rotatably supported by the rear axle housing 20 via this pair of bearings 27.

[0021] The differential gear 17 is of the general type known as a bevel gear. The differential gear includes a pair of side gears 28 and a pair of pinions 30. The pair of side gears 28 are arranged opposite each other along the rotational axis inside the differential case 15. The pair of pinions 30 is rotatably mounted between the pair of side gears 28 via a pinion shaft 29 and meshes with each of the pair of side gears 28. The pinion shaft 29 is fixed to the differential case 15 in a state in which the pinion shaft 29 is perpendicular to the rotational axis of the differential case 15.

[0022] The drive axle pair 18 is integrally connected to the side gear pair 28, respectively. The differential gear unit 19, which includes the differential case 15 and the differential gear 17, drives the drive axle pair 18 to rotate by transmitting torque from the electric motor 11 via the first reduction gear pair 14 and the second reduction gear pair 16, while allowing a speed difference between the drive axle pair 18. A drive axle of the drive axle pair 18 is inserted into the hollow cylindrical output shaft 12 and connected to a rear wheel of a rear wheel pair 31 on a left vehicle side. A pair of sealing components 40 (shown in Fig. 1) is provided accordingly between one drive axle of the drive axle pair 18 and the rear axle housing 20 and between the other drive axle of the drive axle pair 18 and the rear axle housing 20.

[0023] As in Fig. 1, the rear axle housing 20 is formed of four divided portions in the axial direction of the drive axle 18. A partition member 20d is a component of the rear axle housing 20. The partition member 20d has a cylindrical shape. The partition member 20d divides the interior of the rear axle housing 20 into a first wheel chamber 20L (which is an example of a wheel chamber) and a second wheel chamber 20R. The first reduction gear pair 14 is housed in the first wheel chamber 20L. The second reduction gear pair 16 is housed in the second wheel chamber 20R. The rear axle housing 20 further includes a cylindrical first divided housing portion (divided housing portion) 20a, a lid-shaped second divided housing portion 20b, and a lid-shaped third divided housing portion 20c. The first partial housing area 20a is on one side (left side in Fig. 1) of the partition member 20d. The first sub-housing portion 20a has a side wall 20a1 (which is an example of a partition wall) that defines or fixes the first wheel chamber 20L together with the partition member 20d. The second sub-housing portion 20b is attached to the other side (right side in Fig. 1) of the partition member 20d. The second sub-housing portion 20b has a side wall 20b1 that defines the second wheel chamber 20R together with the partition member 20d. The third partition member 20c substantially houses the electric motor 11. The first sub-housing portion 20a, the second sub-housing portion 20b, the third sub-housing portion 20c, and the partition member 20d are components of the rear axle housing 20, and are secured to each other by bolts (screws) (not shown) in an oil-tight manner, as shown in Fig. 1. These partial housing areas 20a, 20b, 20c and the separating component 20d are made of a light metal casting, for example by aluminum die casting or the like.

[0024] As in Fig. As shown in Figure 1, the side wall 20a1 of the first sub-housing portion 20a separates the interior of the first sub-housing portion 20a, so that one side of the first sub-housing portion 20a is the first wheel chamber 20L, and the other side of the first sub-housing portion 20a is a motor chamber 20M in which the electric motor 11 is accommodated. Consequently, it is possible to improve the effect of entraining the lubricating oil with the first reduction gear pair 14. As shown in Fig. 1, one bearing of the bearing pair 24 (which is an example of a bearing supporting the countershaft 13) is provided on a bearing support portion 41 of the side wall 20a1 of the first split case portion 20a, overlapping with a side portion of the countershaft driven gear 23 in the direction of an axis 13a of the countershaft 13. Consequently, it is possible to reduce the length of the countershaft 13 in the direction of the axis 13a. One bearing of the above-described bearing pair 21 and one bearing of the above-described bearing pair 27 are supported by the partition member 20d. A resolver 42 is provided in the motor chamber 20M. The resolver 42 detects the rotation of the electric motor 11. The resolver has a connector portion 42a (see Fig. 2) on its radially outer side. The connector portion 42a is connected to an external circuit (not shown).

[0025] The counter driven gear 23 and the final driven gear 26 are configured to rotate, so that lubricating oil is supplied to the lubricated portions by entraining (scooping) lubricating oil housed at the bottom inside the rear axle housing 20. That is, entraining lubrication is employed in the rear axle 10 according to the present embodiment. Entraining lubrication is provided to supply lubricating oil to the lubricated portions (upward) by entraining lubricating oil housed at the bottom inside the rear axle housing 20. The lubricated portions include, for example, meshing portions of the first reduction gear pair 14 and the second reduction gear pair 16, meshing portions and rotational sliding portions of the differential gear 17, the bearings 21, 27, the bearing of the bearing pair 24 supported by the second sub-housing portion 20b, and the like.

[0026] The rear axle housing 20 has a first catch tank 32 (which is an example of a catch tank) for receiving a portion of the entrained lubricating oil to lower the oil level position of the lubricating oil received at the bottom inside the rear axle housing 20, for the purpose of reducing the stirring or scooping resistance of the lubricating oil against the counter driven gear 23, which increases with an increase in the vehicle speed V. A first oil passage 33 (which is an example of an oil passage) is provided inside the first sub-housing portion 20a of the rear axle housing 20. The first oil passage 33 guides lubricating oil entrained by the counter driven gear 23 of the first reduction gear pair 14 to the first catch tank 32, as indicated by arrow A in FIG. Fig. 2. The first oil passage 33 has an opening end (open end) 33a from which lubricating oil, which is carried along by the rotation of the counter driven gear 23, enters.

[0027] Lubricating oil received in the first reservoir 32 is supplied to a lubricated area from a lubricating oil supply port (not shown) provided in the first reservoir 32, overflows from the first reservoir 32 as a result of accumulation of lubricating oil at or above a predetermined amount, or is supplied as naturally drained oil from a drain port (not shown) provided at the bottom of the first reservoir 32 to areas requiring lubrication, such as bearings and oil seals, which are not immersed in lubricating oil due to a decrease in the oil level position at the bottom in the rear axle housing 20. Therefore, lubricating oil is returned to the bottom inside the rear axle housing 20.

[0028] On the other hand, as in Fig. 1, a second oil passage 34 is provided inside the second sub-housing portion 20b of the rear axle housing 20. The second oil passage 34 carries lubricating oil carried by the final driven gear 26 of the second reduction gear pair 16 to a second receptacle 35. The second receptacle 35, like the first receptacle 32, is provided for receiving carried lubricating oil and lowering the oil level of the lubricating oil stored at the bottom inside the rear axle housing 20. Lubricating oil carried to the second receptacle 35 naturally flows out from a drain hole (not shown) and is returned to the bottom inside the rear axle housing 20.

[0029] Next, the lubrication structure of the above-described bearing 24 supporting the countershaft 13, that is, the bearing 24 provided on the bearing support portion 41 of the side wall 20a1 of the first split case portion 20a overlapping with the side portion of the countershaft driven gear 23 in the direction of the axis 13a, will be described with reference to Fig. 1 to Fig. 3 described.

[0030] As in Fig. As shown in Fig. 2, the first oil passage 33 is formed using the outer periphery of a circular-arc curved portion 43 provided for disposing the connector portion 42a of the resolver 42 on the radially inner side of the curved portion 43. A communication hole 44 is provided on the opening end 33a side of the first oil passage 33 with respect to the curved portion 43 along a tangent L to the curved portion 43 in the first oil passage 33. The communication hole 44 is provided in the side wall 20a1 of the first split case portion 20a and communicates between the first wheel chamber 20L and the motor chamber 20M, which are separated from each other. That is, the first oil passage 33 is connected to the motor chamber 20M via the communication hole 44.The side of the opening end (open end) 33a of the first oil passage 33 with respect to the bulged portion 43 along the tangent L of the bulged portion 43 in the first oil passage 33 is the position where the communication hole 44 is provided, and is a position where lubricating oil entrained to the first oil passage 33 tends to accumulate due to the bulged portion 43. Therefore, it is possible to reliably supply lubricating oil from the first oil passage 33 to the motor chamber 20M by using the communication hole 44.

[0031] As in Fig. 3, a boss portion projection 45 (which is an example of a projecting portion) that centers the resolver 42 is provided on the motor chamber 20M side of the side wall 20a1 of the first sub-housing portion 20a and is arranged on the radially outer side of the resolver 42. The bearing support portion 41 provided in the side wall 20a1 of the first sub-housing portion 20a has a projecting portion 41a (see Fig. 1 and Fig. 3), a bearing hole 41b with a closed end (see Fig. 1) and a retaining ring mounting cutout 41c (see Fig. 1 and Fig. 3). The protruding portion 41 protrudes into the side of the motor chamber 20M. The bearing hole 41b is open to the first wheel chamber 20L and fits and supports the bearing 24. The retaining ring mounting cutout 41c is formed on the protruding portion 41a opening to the motor chamber 20M for holding a retaining ring (circlip) 48 (see Fig. 1 and Fig. 3) for fixing the bearing 24 in the bearing hole 41b.

[0032] As in Fig. 3, the retaining ring mounting cutout 41c is a circular arc-shaped cutout (recess) provided in the protruding portion 41a. The retaining ring mounting cutout 41c is provided to allow a retaining ring pliers (not shown), which is an assembly tool, to enter the protruding portion 41a for the purpose of mounting the retaining ring 48 into both a mounting groove of the protruding portion 41a of the bearing support portion 41 and a mounting groove of the bearing 48. The retaining ring 48 restricts movement of the bearing 24 supported by the bearing support portion 41 in the direction of the axis 13a with respect to the bearing support portion 41.

[0033] The retaining ring pliers are inserted into the protruding portion 41a through the retaining ring mounting cutout 41c. The retaining ring 48, which is fitted to the bearing 24, is held by the retaining ring pliers. The position of the bearing 24 and the position of the bearing support portion 41 are aligned in the direction of the axis 13a. After completing the position alignment, the retaining ring pliers are released from the retaining ring 48. As a result, the retaining ring 48 expands to fit into the above-described mounting grooves of the bearing support portion 41 and the bearing 42. Thus, the mounting of the bearing to the bearing support portion 41 is complete.

[0034] As in Fig. As shown in Figure 3, lubricating oil supplied into the motor chamber 20M via the communication hole 44 flows along the outer periphery of the boss portion protrusion 45, reaches the snap ring mounting cutout 41c, enters the protruding portion 41a via the snap ring mounting cutout 41c, and is then supplied to the bearing 24 supported by the bearing support portion 41. Lubricating oil supplied via the communication hole 44 flows along the outer periphery of the bearing 24 and collects at the bottom in the bearing support portion 41, so that the bearing 24 is immersed in lubricating oil for lubrication. As shown in Fig. 3, the lubricating oil is guided from the communication hole 44 to the boss portion projection 45 via an oil guide rib 47 extending from the side wall 20a1 of the first split case portion 20a.

[0035] As described above, the lubrication structure for a vehicle drive system according to the present embodiment includes the electric motor 11, the countershaft 13, the first reduction gear pair 14 (which is an example of a reduction gear pair), the first catch tank 32 (which is an example of a catch tank), the side wall 20a1 (which is an example of a partition wall), the bearing 24, the first oil passage 33 (which is an example of an oil passage), and the communication hole 44. The electric motor 11 is arranged inside the rear axle housing 20 (which is an example of a housing) of the rear axle 10 (which is an example of a vehicle drive system). The countershaft 13 is rotatably connected to the drive shafts 18 (each being an example of a drive output shaft) of the rear axle 10, and is supported inside the rear axle housing 20 so as to be parallel to the output shaft 12 of the electric motor 11.The first reduction gear pair 14 is provided between the output shaft 12 of the electric motor 11 and the countershaft 13. Lubricating oil, which is stored at the bottom of the rear axle housing 20 and supplied to the lubricated areas, is carried by the first reduction gear pair 14. The first catch tank 32 receives a portion of the lubricating oil. The side wall 20a1 divides the interior of the rear axle housing 20 into the first wheel chamber 20L (which is an example of a wheel chamber), which houses the first reduction gear pair 14, and the motor chamber 20M, in which the electric motor 11 is housed. The bearing 24 is provided on the bearing support portion 41 of the side wall 20a1, overlapping the side portion of the countershaft driven gear 23 (which is an example of a large-diameter gear) of the first reduction gear pair 14 in the direction of the axis 13a. The bearing 24 supports the countershaft 13.The first oil passage 33 (which is an example of an oil passage) is provided in the first gear chamber 20L and guides lubricating oil carried by the counter driven gear 23 to the first catch tank 32. The communication hole 44 is provided in the side wall 20a1 and communicates between the first oil passage 33 and the motor chamber 20M. Lubricating oil supplied into the motor chamber 20M via the communication hole 44 is supplied to the bearing 24. Consequently, the communication hole 44, which communicates between the first oil passage 33 and the motor chamber 20M, is provided in the side wall 20a1, and lubricating oil supplied into the motor chamber 20M via the communication hole 44 is supplied to the bearing 24.Therefore, it is possible to supply lubricating oil carried by the counter driven gear 23 from the first wheel chamber 20L to the motor chamber 20M via the communication hole 44, so that it is possible to lubricate the bearing 24 by using lubricating oil supplied into the motor chamber 20M.

[0036] As described above, with the lubrication structure for a vehicle drive system according to the present embodiment, the first oil passage 33 has the opening end 33a from which lubricating oil enters through the rotation of the counter driven gear 23, the resolver that detects the rotation of the electric motor 11 is provided in the motor chamber 20M, the first oil passage 33 has the bulged portion 43 for disposing the resolver 42 on the radially inner side, and the communication hole 44 is provided on the opening end 33a side of the first oil passage 33 with respect to (opposite) the bulged portion 43. Consequently, the communication hole 44 is provided at a position where entrained lubricating oil tends to accumulate in the first oil passage 33, so that it is possible to reliably supply lubricating oil into the motor chamber 20M via the communication hole 44.

[0037] As described above with the lubricating structure for a vehicle drive system according to the present embodiment, the boss portion protrusion 45 (which is an example of a protruding portion) is positioned on the radially outer side of the resolver 42 and provided on the motor chamber 20M side in the side wall 20a1. The bearing support portion 41 has the protruding portion 41a, the closed-end bearing hole 41b, and the snap ring mounting cutout 41c. The protruding portion 41a protrudes into the motor chamber 20M. The closed-end bearing hole 41b is open to the first wheel chamber 20L and mates with and supports the bearing 24. The snap ring mounting cutout 41c is provided in the protruding portion 41a so as to be open to the motor chamber 20M for holding the snap ring 48 for fixing the bearing 24 in the bearing hole 41b.The lubrication oil supplied into the motor chamber 20M via the connecting hole 44 flows along the outer periphery of the boss portion protrusion 45 and is supplied to the bearing 24 via the snap ring mounting cutout 41c. Consequently, the boss portion protrusion 45, which is used for centering the resolver 42, is allowed to be used as the protruding portion, and it is possible to supply lubricating oil supplied into the motor chamber 20M via the connecting hole 44 to the bearing 24 using the snap ring mounting cutout 41c, which is required for fixing the bearing 24 to the bearing support portion 41, thus eliminating the need to provide an additional component.

[0038] As described above, with the lubrication structure for a vehicle drive system according to the present embodiment, the oil guide rib 47, which guides lubricating oil from the communication hole 44 to the boss portion 45, is provided on the side wall 20a1. Therefore, the guidance of lubricating oil from the communication hole 44 to the boss portion 45 is reliable.

[0039] If there are multiple embodiments, it is clear that it is possible to combine described portions of the respective embodiments with each other as desired, unless otherwise stated.

[0040] It is explicitly emphasized that all features disclosed in the description and / or claims should be considered separate and independent of each other for the purpose of original disclosure as well as for the purpose of limiting the claimed invention, regardless of the feature combinations in the embodiments and / or the claims. It is explicitly stated that all range specifications or specifications of groups of units disclose every possible intermediate value or subset of units for the purpose of original disclosure as well as for the purpose of limiting the claimed invention, in particular also as a limit of a range specification.

Claims

[1] Lubrication assembly for a vehicle drive system (10), the lubrication assembly comprising: a housing (20), an electric motor (11) arranged inside the housing (20), a countershaft (13) rotatably connected to a drive output shaft (18) of the vehicle drive system (10), the countershaft (13) being mounted inside the housing (20) parallel to an output shaft (12) of the electric motor (11), a pair of reduction gears (14) provided between the output shaft (12) of the electric motor (11) and the countershaft (13), a collecting container (32) which receives a portion of the lubricating oil which is received at a bottom in the housing (20) and is supplied to a lubricated area as a result of the lubricating oil being carried along by the reduction gear pair (14), a partition wall (20a1) separating an interior of the housing (20) into a wheel chamber (20L) and a motor chamber (20M), wherein the reduction gear pair (14) is accommodated in the wheel chamber (20L) and the electric motor (11) is accommodated in the motor chamber (20M), a bearing (24) provided on a bearing support portion (41) of the partition wall (20a1) overlapping with a side portion of a large-diameter gear (23) of the reduction gear pair (14) in an axial direction, the bearing (24) supporting the countershaft (13), an oil passage (33) provided in the wheel chamber (20L), the oil passage (33) carrying lubricating oil carried by the large-diameter wheel (23) to the collecting tank (32), and a communication hole (44) provided in the partition wall (20a1), the communication hole (44) providing communication between the oil passage (33) and the motor chamber (20M), in which lubricating oil supplied into the motor chamber (20M) via the connecting hole (44) is supplied to the bearing (24). [2] Lubricating structure according to claim 1, wherein the oil passage (33) has an opening end (33a) from which lubricating oil, which is carried along by rotation of the large-diameter wheel (23), enters, a resolver (42) which detects a rotation of the electric motor (11) is provided in the motor chamber (20M), the oil passage (33) has a curved portion (43) for arranging the resolver (42) on a radially inner side of the curved portion (43), and the communication hole (44) is provided on the side of the opening end (33a) of the oil passage (33) with respect to the curved portion (43). [3] Lubricating structure according to claim 1 or 2, wherein a projecting portion (45) is positioned on a radially outer side of the resolver (42) and is provided on the side of the motor chamber (20M) in the partition wall (20a1), the bearing support portion (41) has a projecting portion (41a), a closed-end bearing hole (41b), and a snap ring mounting cutout (41c), the projecting portion (41a) projecting into the motor chamber (20M), the closed-end bearing hole (41b) being open to the wheel chamber (20L), fitting to and supporting the bearing (24), the snap ring mounting cutout (41c) being provided in the projecting portion (41a) so as to be open to the motor chamber (20M) for holding a snap ring (48) for securing the bearing (24) in the closed-end bearing hole (41b), and Lubricating oil supplied into the motor chamber (20M) via the communication hole (44) flows on an outer periphery of the projecting portion (45) and is supplied to the bearing (24) via the snap ring mounting cutout (41c). [4] A lubricating structure according to claim 3, wherein an oil guide rib (47) which guides the lubricating oil from the communication hole (44) to the projecting portion (45) is provided on the partition wall (20a1).

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