JP2021095941A - Breather mechanism for vehicle power transmission device - Google Patents

Abstract

To provide a breather mechanism, for a vehicle power transmission device, capable of ensuring high space efficiency through preventing a case from getting large in size in a manner that stores a breather chamber in a case without causing reductions in strength and stiffness of a component contributing to power transmission.SOLUTION: A breather mechanism is mounted on a vehicle power transmission device 1 which stores an electric motor 10 and a planetary gear decelerator 20 respectively in a motor chamber MS and a gear chamber GS of a case 2 compartmentalized with a bulkhead 2A and transmits rotation of the electric motor 10 to respective right and left wheel shafts 5L and 5R through the planetary gear decelerator 20. In the breather mechanism, a concave section 23c is formed on a tight contact surface of a carrier (fixing member) 23 tightly fixed to the bulkhead 2A of the planetary gear decelerator 20, a breather chamber S is formed with the concave section 23c and the bulkhead 2A, an air breath hole 2b and an external breath hole 2d are formed on the bulkhead 2A, and the breather chamber S is communicated with the motor chamber MS through the air breath hole 2b so as to be open to the atmosphere through the external breath hole 2d.SELECTED DRAWING: Figure 1

Description

The present invention relates to a breather mechanism of a vehicle power transmission device.

For example, in an electric vehicle using an electric motor as a drive source, a power transmission device including a planetary gear reducer that decelerates the rotation of the electric motor and transmits it to the left and right axles is provided. Some such power transmission devices are configured by accommodating an electric motor and a planetary gear reducer in a motor chamber and a gear chamber of a case partitioned by a partition wall, respectively.

In the above power transmission device, for example, when the temperature of the motor chamber or the gear chamber rises due to the drive of the electric motor, the air in the motor chamber or the gear chamber expands and the internal pressure rises, the motor chamber or the gear chamber rises. There is a problem that the lubricating oil stored in the motor leaks out of the motor chamber and the gear chamber. Therefore, a breather mechanism is provided for communicating the motor chamber and the gear chamber with the atmosphere to maintain the internal pressure of the motor chamber and the gear chamber at a substantially atmospheric pressure.

By the way, conventionally, the breather mechanism has been configured by projecting a part of the case in the axial direction or the radial direction to form a breather chamber and communicating the breather chamber with the atmosphere. If a part of the case is projected in the axial direction or the radial direction, the case becomes larger by that amount, which is not preferable in terms of space efficiency. For example, Patent Document 1 discloses a configuration in which a breather chamber is formed on the outer peripheral portion of a carrier of a planetary gear reducer, but according to such a configuration, a part of the case protrudes outward in the radial direction. , There is a problem that the case becomes large and space efficiency deteriorates.

Therefore, in Patent Document 2, a groove is formed on the outer peripheral portion of the ring gear fixed to the inner circumference of the case accommodating the planetary gear reducer, and a breather chamber is formed between the groove and the inner peripheral surface of the case. The configuration to do is proposed. According to such a configuration, the breather chamber can be formed without projecting a part of the case outward in the radial direction, so that the space efficiency of the case can be improved.

Japanese Patent No. 5487317 Japanese Patent No. 2712895

However, in the breather structure proposed in Patent Document 2, if a groove is formed in the outer peripheral portion of the ring gear of the planetary gear reducer in order to form the breather chamber, there is a problem that the strength and rigidity of the ring gear responsible for power transmission are lowered. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to secure a breather chamber in the case without reducing the strength and rigidity of parts that contribute to power transmission, and prevent the case from becoming large. An object of the present invention is to provide a breather mechanism for a vehicle power transmission device that can ensure high space efficiency.

In order to achieve the above object, the present invention provides an electric motor (10) and a planetary gear reducer (20) in the motor chamber (MS) and gear chamber (GS) of the case (2) partitioned by the partition wall (2A). It is a breather mechanism provided in the vehicle power transmission device (1) that accommodates each of them and transmits the rotation of the electric motor (10) to the left and right axles (5L, 5R) via the planetary gear reducer (20). A recess (23c) is formed on the contact surface of the fixing member (23) that is closely fixed to the partition (2A) of the planetary gear reducer (20), and the recess (23c) and the partition (2A) are formed. To form a breather chamber (S), an air breathing hole (2b) and an external breathing hole (2d) are formed in the partition wall (2A), and the breather chamber (S) is formed into the air breathing hole (2b). The motor chamber (MS) is communicated with the motor chamber (MS), and the motor chamber (MS) is opened to the atmosphere through the external breathing hole (2d).

According to the present invention, a recess is formed on the contact surface of the fixing member that is closely fixed to the partition wall of the planetary gear reducer, and the breather chamber is formed by the recess and the partition wall. It is not necessary to project a part of the case in the radial direction or the axial direction, and it is possible to prevent the case from becoming large and improve its space efficiency.

Further, since the recess for forming the breather chamber is formed in the fixing member that does not contribute to the power transmission of the planetary gear reducer, the strength and rigidity of parts such as gears that contribute to the power transmission are not lowered.

In the breather mechanism, the fixing member (23) is a carrier (23) that rotatably supports a plurality of planetary gears (22) in the planetary gear reducer (20), and is a circumference of the carrier (23). A plurality of spaces (S1 to S3) formed by forming the recess (23c) between the support portions of the two planetary gears (22) adjacent to each other in the direction and forming the recess (23c) and the partition wall (2A), respectively. ) May communicate with each other to form the breather chamber (S).

According to the above configuration, since a necessary and sufficient volume can be secured in the breather chamber by the plurality of spaces, the breather mechanism provided with the breather chamber can sufficiently fulfill the original breather function.

Further, in the breather mechanism, the space (S1) located above the plurality of spaces (S1 to S3) constituting the breather chamber (S) is passed through the air breathing hole (2b) to the motor. While communicating with the chamber (MS), it is opened to the atmosphere through the external breathing hole (2d), and the space (S1) located above and the other space (S2, S3) located below are rehydrated. The spaces (S2, S3) located below are communicated with each other through the passage (23d), and the spaces (S2, S3) located below are communicated with the motor chamber (MS) through the oil return hole (2f) formed in the partition wall (2A). You may let me.

According to the above configuration, when the internal pressure of the motor chamber rises, the air expanded in the motor chamber flows into the upper space through the air breathing hole formed in the partition wall, and the air flowing into this space is discharged. It is discharged into the air through an external breathing hole formed in the partition wall. Therefore, the internal pressure of the motor chamber is maintained at substantially atmospheric pressure. Then, the oil contained in the air in the motor chamber is separated from the air in the upper space and removed, and the oil separated from this air flows to the lower space through the oil return passage and from the lower space. Since the oil is returned to the motor chamber through the oil return hole, the oil does not leak out of the case, and the necessary and sufficient oil is always secured in the motor chamber. When the internal pressure of the motor drops below atmospheric pressure because the temperature of the motor chamber drops after the motor stops, the outside air flows into the upper space through the external breathing hole and flows into this space. Since the outside air flows into the motor chamber through the air breathing hole, the motor chamber is maintained at approximately atmospheric pressure.

Further, in the breather mechanism, the inner diameter of the external breathing hole (2d) may be set larger than the inner diameter of the air breathing hole (2b).

According to the above configuration, the air containing the oil mist that flows from the motor chamber through the air breathing hole into the breather chamber is decelerated when passing through the external breathing hole. Oil is separated and removed from the air. Therefore, only the air from which the oil has been removed is discharged into the atmosphere, and the discharge of the oil into the atmosphere is effectively prevented.

According to the present invention, there is an effect that a breather chamber can be secured in the case to prevent the case from becoming large and high space efficiency can be ensured without causing a decrease in strength and rigidity of parts that contribute to power transmission. can get.

It is a vertical cross-sectional view of the power transmission device main part for a vehicle provided with the breather mechanism which concerns on this invention. It is a partial perspective view which shows the state which the planetary gear reducer is removed from the case of the power transmission device for a vehicle provided with the breather mechanism which concerns on this invention. It is a perspective view of a planetary gear transmission. FIG. 3 is a view in the direction of arrow A in FIG. FIG. 3 is a cross-sectional view taken along the line BB of FIG. It is a vertical sectional perspective view of the power transmission device for a vehicle provided with the breather mechanism according to the present invention in a state where the motor is removed. It is an enlarged detailed view of part C of FIG. FIG. 2 is a cross-sectional view taken along the line DD of FIG. FIG. 2 is a cross-sectional view taken along the line EE of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[Vehicle power transmission device]
First, the configuration of the vehicle power transmission device including the breather mechanism according to the present invention will be described below with reference to FIG.

FIG. 1 is a vertical sectional view of a main part of a vehicle power transmission device. In the illustrated vehicle power transmission device 1, an electric motor 10 and a planetary gear reducer 20 as drive sources are housed in a tubular case 2. They are housed side by side in the width direction (horizontal direction in FIG. 1). More specifically, the inside of the case 2 is divided into a motor chamber MS and a gear chamber GS by a vertical wall-shaped partition wall 2A, an electric motor 10 is housed in the motor chamber MS, and a planetary gear reducer is housed in the gear chamber GS. 20 is housed. One end opening of the gear chamber GS of the case 2 is covered with a cover 4 attached to the case 2 by a plurality of bolts (only one is shown in FIG. 1) 3.

Here, the electric motor 10 is a three-phase brushless motor, and includes a ring-shaped stator 11 fixed to the inner peripheral surface of the case 2 and a rotor 12 rotatably housed inside the stator 11. I have. A coil 13 for three phases is wound around the stator 11, and a plurality of permanent magnets (not shown) are built in the rotor 12.

By the way, one of the two left and right axles 5L and 5R (left side in FIG. 1) extending in the vehicle width direction is rotatably inserted into the center of the axle of the rotor 12 of the electric motor 10. A hollow output shaft (motor shaft) 14 of the electric motor 10 is fitted on the outer circumference of the axle 5L so as to be relatively rotatable. Here, the output shaft (motor shaft) 14 is inserted and fitted to the center of the shaft of the rotor 12 and rotates integrally with the rotor 12. Drive wheels (not shown) are attached to the outer ends of the left and right axles 5L and 5R in each axial direction.

Further, the planetary gear reducer 20 includes a sun gear 21 having a small diameter rotatably supported by one axle 5L (on the left side in FIG. 1) and a plurality of sun gears 21 that mesh with the sun gear 21 (three in the present embodiment: The planetary gears 22 (see FIGS. 2 and 3) and a carrier 23 as a fixing member that rotatably supports these planetary gears 22 are provided.

Here, the carrier 23 is configured by assembling and integrating the two members 23A and 23B with a plurality of bolts (only one is shown in FIG. 1) 38, and the carrier 23 has three bearings (FIG. 1). The rotating shaft 24 (shown only one) is rotatably supported at both ends in the axial direction by a ball bearing 25 and a needle bearing 26. Each planetary gear 22 is fitted on the outer circumference of each rotating shaft 24 by spline fitting. Further, a small-diameter gear 27 is integrally formed on the outer periphery of a portion of each rotating shaft 24 adjacent to the planetary gear 22.

By the way, the sun gear 21 is connected to the output shaft (motor shaft) 14 of the electric motor 10 by spline fitting and rotates integrally with the output shaft (motor shaft) 14, which is connected to the carrier 23 by a ball bearing 28. It is rotatably supported.

Further, a differential device (differential device) 30 is housed in the gear chamber GS covered by the cover 4 of the case 2. The differential device 30 includes a spherical shell-shaped differential case 31 whose left and right sides are rotatably supported by a carrier 23 and a cover 4 by ball bearings 29. A pinion shaft 32 is inserted and fixed to the central portion of the differential case 31 in a direction orthogonal to the axial directions of the axles 5L and 5R (vertical direction in FIG. 1), and a pinion is inserted inside the differential case 31. A pair of pinion gears (bevel gears) 33 rotatably supported by a shaft 32 and a pair of side gears (bevel gears) 34 meshing with the pinion gears 33 are housed. Here, the pair of side gears 34 are spline-fitted to the inner ends of the left and right axles 5L and 5R in each axial direction, and can rotate integrally with the left and right axles 5L and 5R, respectively.

Further, a large-diameter ring gear 35 is formed in the differential case 31, and the ring gear 35 has a plurality of (three in the present embodiment) rotating shafts 24 rotatably supported by the carrier 23. The small-diameter gears 27 integrally formed with each other are meshed with each other.

By the way, the carrier 23 is fixed to the case 2 in a state where one end surface in the axial direction (left end surface in FIG. 1) is in close contact with one end surface (right end surface in FIG. 1) of the partition wall 2A of the case 2. More specifically, the carrier 23 has a circular concave step portion (a circular concave step portion) in which a convex step portion (shoulder portion) 23a formed on the outer periphery of the end portion on the partition wall 2A side (left side in FIG. 1) is formed on the end surface of the partition wall 2A. Case 2 (bulkhead 2A) by being fitted into the inlay portion 2a and spline fitting the outer periphery of the sleeve portion 23b, which integrally projects from one end on the partition wall 2A side toward the partition wall 2A, to the inner circumference of the partition wall 2A. It is fixed to.

In the vehicle power transmission device 1 configured as described above, when the coil 13 wound around the stator 11 of the electric motor 10 is energized from a battery (not shown) to activate the electric motor 10, the coil 13 is activated. The rotor 12 rotates at a predetermined speed together with the output shaft (rotor shaft) 14 due to the electromagnetic induction action of the flowing current. Then, the rotation of the output shaft (motor shaft) 14 is decelerated from the sun gear 21 via the plurality of planetary gears 22 and transmitted to each rotating shaft 24, and each rotating shaft 24 rotates at a predetermined speed. Then, the rotation of these rotating shafts 24 is decelerated via a small-diameter gear 27 and a large-diameter ring gear 35 integrally formed on each rotating shaft 24, and is transmitted to the differential case 31 of the differential device 30 to be transmitted to the differential. The case 31 rotates at a predetermined speed.

When the differential case 31 of the differential device 30 rotates as described above, the rotational power input to the differential device 30 is distributed and transmitted to the left and right axles 5L and 5R, so that the left and right axles 5L and 5R and these Drive wheels (not shown) attached to the outer ends of the axles 5L and 5R in the axial direction are rotationally driven to drive the vehicle. Here, when the vehicle travels straight, the resistance received from the road surface by the left and right drive wheels is equal, so the pair of pinion gears 33 revolve together with the differential case 31, and the rotational power is distributed to the pair of left and right side gears 34 to the left and right. It is transmitted to the axles 5L and 5R of. At this time, the pair of pinion gears 33 do not rotate (rotate).

On the other hand, when the vehicle is turning, there is a difference in the resistance received from the road surface by the left and right drive wheels (difference in the moving distance of the left and right drive wheels), so that the pair of pinion gears 33 rotate on one side. The rotation speed of the side gear 34 is made faster than the rotation speed of the other side gear 34, and the rotational power is distributed and transmitted to the left and right axles 5L and 5R while smoothly cornering the vehicle.

[Breather mechanism]
Next, the breather mechanism provided in the vehicle power transmission device 1 described above will be described below with reference to FIGS. 2 to 9.

FIG. 2 is a partial perspective view showing a state in which the planetary gear reducer is removed from the case of the vehicle power transmission device provided with the breather mechanism according to the present invention, FIG. 3 is a perspective view of the planetary gear transmission, and FIG. 4 is FIG. A view in the direction of arrow A, FIG. 5 is a sectional view taken along line BB of FIG. 3, FIG. 6 is a vertical sectional perspective view of the vehicle power transmission device with the motor removed, and FIG. 7 is an enlarged detail of part C of FIG. 8 is a cross-sectional view taken along the line DD of FIG. 2, and FIG. 9 is a cross-sectional view taken along the line EE of FIG.

The breather mechanism according to the present embodiment is for keeping the internal pressure of the motor chamber MS constant (atmospheric pressure) by moving air in and out of the motor chamber MS of the case 2, and this breather mechanism. In the above, three front-view fan-shaped recesses 23c (see FIGS. 3 to 5) formed on the contact surface of the carrier 23 of the planetary gear reducer 20 with the case 2 to the partition wall 2A, and three partition walls 2A covering them. Spaces S1, S2 and S3 are formed. The spaces S1 to S3 form a breather chamber S that communicates with each other by the oil return passage 23d shown in FIG. 7 (see FIGS. 1 and 7 to 9). Here, as shown in FIGS. 3 and 4, on the contact surface of the carrier 23 with respect to the partition wall 2A, the support portion (support portion of the rotating shaft 24) of each planetary gear 22 of the planetary gear reducer 20 in the circumferential direction. Recesses 23c are formed at three positions between them at an equal angle pitch (120 ° pitch). Therefore, the three spaces S1, S2, and S3 formed by covering these three recesses 23c with the partition wall 2A of the case 2 are also formed at equal angles in the circumferential direction.

Further, as shown in FIGS. 2 and 7, an air breathing hole 2b that communicates the motor chamber MS and the upper space S1 is formed in the upper part of the partition wall 2A of the case 2. Further, as shown in FIG. 8, a recess 2c is formed on the end surface of the upper portion of the partition wall 2A of the case 2 facing the upper space S1, and the recess 2c is formed in the upper space S1. It is opened as a large-diameter circular external respiration hole 2d (see FIG. 7). Here, the inner diameter of the external respiration hole 2d is set to be larger than the inner diameter of the air respiration hole 2b.

Then, as shown in FIG. 8, the partition wall 2A of the case 2 is formed with an external respiration passage 2e that extends upward from the recess 2c formed therein and opens into the atmosphere. An L-shaped breather pipe 6 press-fitted to the upper part of the case 2 is connected to 2e. Therefore, the upper space S1 communicates with the atmosphere through the external respiration hole 2d and the recess 2c formed in the partition wall 2A of the case 2, the external respiration passage 2e, and the breather pipe 6.

Further, as shown in FIGS. 2 and 9, a circular oil return hole 2f is formed in the lower portion of the partition wall 2A of the case 2, and the recess 23c formed in the carrier 23 and the partition wall 2A of the case 2 are formed. The lower spaces S2 and S3 formed by the above and the motor chamber MS communicate with each other through the oil return hole 2f.

As described above, in the breather mechanism according to the present embodiment, the oil shown in FIG. 7 represents the three spaces S1 to S3 formed by the three recesses 23c formed in the carrier 23 and the partition wall 2A of the case 2 covering them. The breather chamber S is provided so as to communicate with each other by the return passage 23d. Here, the upper space S1 of the three spaces S1 to S3 constituting the breather chamber S communicates with the motor chamber MS via the air breathing hole 2b formed in the upper part of the partition wall 2A of the case 2. It communicates with the atmosphere through the external respiration hole 2d formed in the partition wall 2A, the external respiration passage 2e, and the breather pipe 6. Further, the lower two spaces S2 and S3 of the three spaces S1 to S2 constituting the breather chamber S communicate with the motor chamber MS via the oil return hole 2f formed in the lower part of the partition wall 2A of the case 2. doing.

Next, the operation of the breather mechanism configured as described above will be described.

In the state where the vehicle power transmission device 1 shown in FIG. 1 is operating, the temperature of the motor chamber MS rises due to the drive of the electric motor 10 housed in the motor chamber MS of the case 2, and the air in the motor chamber MS rises. When the internal pressure of the motor chamber MS rises due to the expansion, the air containing the oil mist of the motor chamber MS passes through the air breathing hole 2b formed in the partition wall 2A of the case 2 as shown by the arrow a in FIG. It flows into the space S1 of the above, and flows from this space S1 into the other lower spaces S2 and S3 through the oil return hole 2f. Then, the air containing the oil mist that has flowed into the three spaces S1 to S3 constituting the breather chamber S is separated and removed by the difference in the specific densities of the air and the oil in each of the spaces S1 to S3, and the oil is removed. As shown by the arrow b in FIG. 7, the air from which the mist has been removed is sent from the breather pipe 6 into the atmosphere through the recess 2c and the external breathing passage 2e from the external breathing hole 2d formed in the partition wall 2A of the case 2. Is discharged. Therefore, the increase in the internal pressure of the motor chamber MS is prevented, and the motor chamber MS is maintained at substantially atmospheric pressure.

By the way, in the present embodiment, since the inner diameter of the external respiration hole 2d is set to be larger than the inner diameter of the air respiration hole 2b as described above, the upper space S1 passes through the air respiration hole 2b from the motor chamber MS. The air containing the oil mist flowing into the air is decelerated as it passes through the external breathing hole 2d. Therefore, due to the difference in density between air and oil (the density of oil is higher than the density of air), the oil is separated and removed from the air, and only the air from which the oil has been removed has the recess 2c and the external breathing passage 2e. It is discharged from the breather pipe 6 into the atmosphere through the breather pipe 6. Therefore, the discharge of oil into the atmosphere can be effectively prevented.

Further, the oil separated from the air containing the oil mist flows from the upper space S1 to the lower spaces S2 and S3 through the oil return passage 23d as shown by the arrow c in FIG. It is returned from the spaces S2 and S3 to the motor chamber MS through the oil return hole 2f of the partition wall 2A. Therefore, the oil (lubricating oil) in the motor chamber MS does not leak to the outside of the case 2, and therefore the amount of oil does not decrease due to the breather action, and the oil necessary and sufficient for the motor chamber MS is always sufficient. The amount is secured.

On the other hand, when the drive of the electric motor 10 is stopped and the temperature of the motor chamber MS is lowered and the internal pressure of the motor chamber MS is lowered to the atmospheric pressure or less, the outside air is sent to the motor chamber MS through the reverse route. Inflow to. That is, the outside air flows from the breather pipe 6 into the external breathing passage 2e and the recess 2c of the partition wall 2A, and flows from the recess 2c through the external breathing hole 2d of the partition wall 2A into the upper space S1. Then, the outside air that has flowed into the upper space S1 flows into the motor chamber MS through the air breathing hole 2b formed in the partition wall 2A, so that the decrease in the internal pressure of the motor chamber MS is prevented, and the motor chamber MS , It is kept at about atmospheric pressure.

As described above, in the breather mechanism according to the present embodiment, three recesses 23c are formed on the contact surface of the carrier 23 which is closely fixed to the partition wall 2A of the case 2 of the planetary gear reducer 20, and the recesses 23c are formed. Three spaces S1, S2, and S3 are formed by the 23c and the partition wall 2A, and these spaces S1 to S3 are communicated with each other to form a breather chamber S. Therefore, in order to form the breather chamber S, a case 2 is formed. It is not necessary to project a part of the case 2 in the radial direction or the axial direction, and it is possible to prevent the case 2 from becoming large in size and improve its space efficiency.

Further, since the necessary and sufficient volume can be secured in the breather chamber S by the three spaces S1 to S3, the breather mechanism provided with the breather chamber S can sufficiently fulfill its original breather function.

Further, in the breather mechanism according to the present embodiment, the breather chamber S is configured by communicating the three spaces S1 to S3 with each other, and the planetary gear reducer has three recesses 23c for forming the spaces S1 to S3. Since it is formed on the carrier 23 that does not contribute to the power transmission of 20, the strength and rigidity of parts such as the sun gear 21 and the planetary gear 22 that contribute to the power transmission do not decrease.

In the present embodiment, three spaces S1 to S3 are formed by forming three recesses 23c in the carrier 23 which is a fixing member of the planetary gear reducer 20, and these spaces S1 to S3 are communicated with each other. The breather chamber S was formed, but the number of recesses 23c and spaces S1 to S3 need not be three and is arbitrary.

In addition, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of claims and the technical ideas described in the specification and drawings.

1 Vehicle power transmission device 2 Case 2A Case partition 2b Air breathing hole 2c Case recess 2d External breathing hole 2e External breathing passage 2f Oil return hole 5L, 5R Axle 6 Breather pipe 10 Electric motor 20 Planetary gear reducer 21 Sun gear 22 Planetary gear 23 carrier (fixing member)
23c Carrier recess 23d Oil return passage 24 Rotating shaft MS Motor room GS Gear room S Breather room S1 to S3 Space

Claims (4)

A vehicle power transmission device in which an electric motor and a planetary gear reducer are housed in the motor chamber and the gear chamber of the case partitioned by a partition wall, and the rotation of the electric motor is transmitted to the left and right axles via the planetary gear reducer, respectively. It is a breather mechanism provided in
A recess is formed on the contact surface of the fixing member fixed to the partition of the planetary gear reducer in close contact with the partition, and a breather chamber is formed by the recess and the partition.
An air breathing hole and an external breathing hole are formed in the partition wall to form an air breathing hole and an external breathing hole.
A breather mechanism for a vehicle power transmission device, characterized in that the breather chamber is communicated with the motor chamber through the air breathing hole and is opened to the atmosphere through the external breathing hole. The fixing member is a carrier that rotatably supports a plurality of planetary gears in the planetary gear reducer, and each of the recesses is formed between two adjacent planetary gear support portions in the circumferential direction of the carrier. The breather mechanism for a vehicle power transmission device according to claim 1, wherein the breather chamber is formed by communicating a plurality of spaces formed by the recess and the partition wall with each other. Of the plurality of spaces constituting the breather chamber, a space located above is communicated with the motor chamber via the air breathing hole, and is opened to the atmosphere through the external breathing hole, and is placed above the space. The space located and the other space located below are communicated with each other via the oil return passage.
The breather mechanism for a vehicle power transmission device according to claim 2, wherein the space located below is communicated with the motor chamber through an oil return hole formed in the partition wall. The breather mechanism for a vehicle power transmission device according to any one of claims 1 to 3, wherein the inner diameter of the external breathing hole is set to be larger than the inner diameter of the air breathing hole.

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