JP2013061034A - Power transmission device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that only a single breather arranged at the upper part of an air chamber cannot ventilate the inside and outside of the air chamber, prevent water from flowing into the air chamber and discharge oil leaked from an oil chamber to the air chamber in a power transmission device for vehicle in which the oil chamber is adjacent to the air chamber.SOLUTION: The power transmission device for vehicle includes: an oil chamber case 26 in which a transmission 18 is housed and oil is stored; and a housing 22 whose inside is the air chamber, in which an electric motor 12 is housed. The case 26 and the housing 22 are arranged to be adjacent to each other and an output shaft of the transmission 18 is connected to an input shaft of the electric motor 12. The power transmission device for vehicle also includes: a first breather 27 arranged at the upper part of the case 26, which adjusts internal pressure of the case 26; and a second breather 28 arranged at the lower part of the housing 22, which has a valve body for normally communicating with the inside and outside of the housing and shutting off the communication between the inside and outside of the housing by buoyancy by water or water pressure energized from the outside to the inside of the housing.

Description

  The present invention relates to a vehicle power transmission device in which an air chamber and an oil chamber are provided adjacent to each other, and in particular, is provided in a main body of the vehicle power transmission device and maintains communication between the inside and the outside of a housing whose inside is an air chamber. In particular, the present invention relates to a structure of a vehicle power transmission device including a breather that prevents inflow of water from the outside.

  At least a vehicle power transmission device such as an electric vehicle or a hybrid vehicle that travels using an electric motor as a drive source is connected to the output shaft of the electric motor and the input shaft of the transmission, and the interior in which the electric motor is accommodated is an air chamber housing; In some cases, the interior in which the transmission is accommodated is disposed adjacent to the case of the oil chamber. In particular, the housing in which the electric motor is accommodated may be provided with an air hole communicating with the outside air in order to cool the electric motor by circulation of air.

  When such a vehicle travels in a puddle, water or muddy water picked up by the vehicle flows into the housing through an air hole communicating between the inside and outside of the housing, causing a reduction in motor performance due to leakage or rusting of the motor. There is a risk. Therefore, it is conceivable to eliminate air holes and prevent the inflow of water into the housing by making the housing a sealed structure.

  However, if the housing in which the electric motor is accommodated has a sealed structure, the electric motor is driven at a high speed, and therefore the inside of the sealed housing may rise to a high temperature due to the heat of the electric motor. Then, since the torque controllability of the electric motor changes due to the influence of heat on the characteristics of the magnet and the like used in the electric motor, it is not desirable to make the housing a sealed structure in order to ensure air cooling of the electric motor.

  In this regard, in order to air-cool the inside of the housing while preventing inflow of water into the housing, for example, it is conceivable to provide a breather that communicates between the inside and outside of the housing as in Patent Document 1. The breather disclosed in Patent Document 1 is provided at the upper part of the case of the transmission, and by communicating the inside and outside of the case, the high-temperature air in the case is discharged to the outside and the pressure is adjusted. Oil leakage from the breather is prevented. It is conceivable to provide a breather provided in the upper part of the case of this transmission in the housing. Thereby, since the inside and outside of the housing communicate with each other, the high-temperature air in the housing can be discharged to the outside. In particular, by providing the breather at the upper part of the case of the transmission, it is possible to make it difficult for water to flow into the housing through the breather when the vehicle travels in a puddle or the like.

JP-A-9-310773

  However, if a breather is provided in the upper part of the housing of the air chamber when the electric motor is accommodated, it is difficult to detect the oil leaking from the case through the seal part of the housing and the bearing of the housing and discharging it from the breather. Become. For this reason, if a breather is provided at the lower part of the housing in order to make it easy to discharge leaked oil from the housing, water may flow into the housing through the breather when the vehicle travels in a water pool or the like. In addition, if a breather is provided at the top of the housing of the air chamber where the motor is housed and an oil discharge port is provided at the bottom of the housing, the number of holes communicating with the inside and outside of the housing increases, so that water is contained inside the housing. It becomes easy to flow in.

  SUMMARY OF THE INVENTION The present invention solves the above problem, and an object thereof is to provide a vehicle power transmission device in which an oil chamber case in which a transmission is accommodated and an air chamber housing in which an electric motor is accommodated are disposed adjacent to each other. It is an object of the present invention to provide a vehicle power transmission device that performs ventilation of a housing, discharge of oil leaked from a case into the housing, and prevention of water inflow from the outside into the housing with a single breather.

  A vehicle power transmission device according to a first aspect of the present invention includes an oil chamber case in which a transmission is accommodated and oil is accommodated therein, and an interior in which an electric motor is accommodated includes a housing of an air chamber, A housing is disposed adjacent to each other, and is a vehicle power transmission device in which an input shaft of the transmission and an output shaft of the electric motor are connected. The vehicle power transmission device is provided at an upper portion of the case and adjusts an internal pressure of the case. The breather is provided at the lower part of the housing and normally communicates with the inside and outside of the housing and shuts off the communication between the inside and outside of the housing by water buoyancy or water pressure urged from the outside of the housing toward the inside of the housing. And a second breather having a body.

  In the vehicle power transmission device according to a second aspect of the present invention, in the first aspect, the second breather is configured by a through hole that communicates the inside and outside of the housing, and a valve body that is accommodated in the through hole. The through hole has a substantially cylindrical shape, the valve body has a substantially cylindrical shape having an outer diameter smaller than the diameter of the through hole, and an annular outer periphery having a groove bottom diameter smaller than the outer diameter of the valve body. A groove is provided on the outer peripheral surface, a seal ring is accommodated in the annular outer peripheral groove, and an outer diameter of the seal ring is smaller than a hole diameter of the through hole and larger than an outer diameter of the valve body, and an inner diameter of the seal ring Is larger than the groove bottom diameter of the annular outer circumferential groove, and the thickness of the seal ring is smaller than the groove width of the annular outer circumferential groove on the outer circumferential surface of the valve body.

  According to a third aspect of the present invention, there is provided the vehicle power transmission device according to the second aspect, wherein the groove width and the thickness of the seal ring are larger than the gap due to the difference between the hole diameter of the through hole and the outer diameter of the seal ring. The gap due to the difference is larger.

  According to a fourth aspect of the present invention, there is provided the vehicle power transmission device according to any one of the second to third aspects, wherein the through hole is a hole in an external opening that opens to the outside of the housing rather than an internal opening that opens to the inside of the housing. The through hole has an annular step surface due to a difference in hole diameter between the outer opening and the inner opening, and an annular sealing material is provided on the step surface, and the valve body includes the through hole. Is provided between the valve body and the annular sealing material, and has a gap communicating between the inside and the outside of the housing, and is movable in a direction to close the gap until the valve body is in close contact with the annular sealing material. It is characterized by being.

  According to a fifth aspect of the present invention, there is provided the vehicle power transmission device according to the fourth aspect, further comprising an elastic body between the upper surface of the valve body and the step surface.

  A vehicle power transmission device according to a sixth aspect of the present invention is characterized in that, in the first to fifth aspects of the invention, a filter is provided in the external opening of the through hole.

  According to the first invention, the first breather provided at the upper part of the case for adjusting the internal pressure of the case, and provided at the lower part of the housing. And a second breather having a valve body that blocks communication between the inside and outside of the housing by water pressure biased toward the inside of the housing from the outside of the housing. Thereby, since the pressure in the case is released by the first breather, the oil in the case is suppressed from leaking into the housing through the seal portion. In addition, the inside and outside of the housing are normally ventilated by the second breather, and oil leaking into the housing is discharged to the outside. On the other hand, when water flows from the outside, a valve body that blocks communication between the inside and outside of the housing by water buoyancy or water pressure suppresses the inflow of water into the housing. Therefore, it is possible to vent the inside and outside of the housing, discharge the oil leaked into the housing, and prevent the inflow of water from the outside into the housing with only the second breather without increasing the number of discharge ports. .

  According to the second invention, the valve body has a substantially cylindrical shape having an outer diameter smaller than the diameter of the through hole, and an annular outer periphery having a groove bottom diameter smaller than the outer diameter of the valve body. A groove is provided on the outer peripheral surface, and a seal ring is accommodated in the annular outer peripheral groove, and an outer diameter of the seal ring is smaller than a hole diameter of the through hole and larger than an outer diameter of the valve body. Is larger than the bottom diameter of the annular outer circumferential groove, and the thickness of the seal ring is smaller than the groove width of the annular outer circumferential groove on the outer circumferential surface of the valve body. As a result, a communication path that communicates between the inside and outside of the housing is formed by a gap between the inner wall of the through hole and the valve body at normal times, and the inside and outside of the housing is ventilated and the oil leaked into the housing is discharged. When traveling in a puddle, the seal ring is lifted by water pressure, water enters the annular outer circumferential groove of the valve body, and the seal ring is expanded and deformed from the inside by the water that enters, so that the communication path is blocked. Inflow of water into the room is suppressed.

  According to the third invention, the gap due to the difference between the groove width and the thickness of the seal ring is larger than the gap due to the difference between the hole diameter of the through hole and the outer diameter of the seal ring. As a result, water easily enters the annular outer circumferential groove of the valve body, so that the communication path can be easily blocked by expanding and deforming the seal ring. Therefore, the inflow of water into the housing is more reliably suppressed.

  According to a fourth aspect of the present invention, the valve body is accommodated on the outer opening side of the through hole, and includes a gap that communicates the inside and outside of the housing between the valve body and the annular sealing material, and the gap The valve body can be moved in a direction to close the ring until the valve body comes into close contact with the annular sealing material. As a result, a communication path is formed by a gap between the annular seal member and the valve body at normal times, and the oil leaking into the air chamber is discharged while ventilating outside the air chamber. When a water pressure is applied from the outside, the valve body is moved upward and closes the communication path by being in close contact with the annular sealing material, so that the inflow of water into the housing is suppressed.

  Moreover, according to 5th invention, the elastic body is provided between the upper surface of the said valve body, and the said level | step difference surface. Thereby, when water pressure is not applied from the outside, a communication path is formed between the valve body and the annular seal member by the reaction force of the elastic body, so that ventilation can be reliably performed without applying water pressure.

  According to a sixth aspect of the present invention, the through hole includes a filter in its external opening. Thereby, since the penetration | invasion of a foreign material is suppressed by the said filter, damage to the said valve body and the said seal ring is suppressed.

It is a figure which shows the power transmission device for vehicles with which the vent valve apparatus which concerns on one Example of this invention is applied. It is sectional drawing which shows the Example of a 1st breather. It is sectional drawing which shows the Example of a 2nd breather. It is the figure which showed the perspective view of the valve body which comprises the 2nd breather of FIG. It is the figure which showed the normal state about the 2nd breather of FIG. It is the figure which showed the state which closed the communication path | route with the seal ring about the 2nd breather of FIG.

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

  FIG. 1 is a diagram showing a vehicle power transmission device to which a vent valve device according to an embodiment of the present invention is applied. The output shaft of the electric motor 12 is connected to the engine 10 via the clutch 14. The output shaft of the electric motor 12 is connected to the transmission 18 via the torque converter 16. The interior of the housing 22 in which the electric motor 12 is accommodated is configured as an air chamber 20, and the interior of the case 26 in which the transmission 18 is accommodated is an oil chamber 24 in which oil for hydraulic control and lubrication of the transmission 18 is accommodated. Composed. The housing 22 and the case 26 are connected adjacent to each other, the first breather 27 of this embodiment is provided on the upper surface of the case 26, and the second breather 28 is provided on the bottom surface of the housing 22.

  The first breather 27 is provided at an upper portion of the case 26 and includes a breather pipe insertion port 31 that communicates inside and outside the case 26 and a breather pipe 29 that is press-fitted into the breather pipe insertion port 31. As a result, the inside and outside of the case 26 are communicated with each other by the breather pipe 29 to adjust the pressure difference between the inside and outside of the case 26.

  The shape of the breather pipe 29 may be such that the end is bent into an L shape or the tip of the breather pipe 29 is directed downward to make it difficult for foreign matter to enter the case 26 through the breather pipe 29. You may do it. The breather pipe 29 may have a configuration in which a porous filter or a cap is provided at the tip of the breather pipe 29.

  FIG. 2 is a cross-sectional view showing in detail the second breather 28 provided at the lower part or bottom of the housing 22. The second breather 28 includes a through hole 30 provided in the housing 22, a valve body 36 accommodated in the through hole 30, a seal ring 48 that moves or expands and deforms due to water pressure to close the side communication path 41, An annular sealing material 38 that closes the communication path 42 in close contact with the valve body 36, a spring 46 that biases the valve body 36 and the step surface 56 in a direction to open the communication path 42, and an opening of the through hole 30 are provided. The filter 44 prevents foreign matter from entering from the outside.

  As shown in FIG. 2, the through hole 30 provided in the housing 22 includes an external opening 32 that opens to the outside of the housing 22, an internal opening 34 that has a hole diameter smaller than the hole diameter, and an external opening 32. And a step surface 56 due to a difference in hole diameter between the internal opening 34 and the internal opening 34. That is, the housing 22 is formed with a through-hole 30 whose internal space has a substantially convex shape in a sectional view. An annular sealing material 38 such as packing is fixed to the step surface 56, and the upper surface of the valve body 36 is brought into close contact with the annular sealing material 38 to prevent water from flowing into the housing 22. An annular inner peripheral groove 50 for fitting the snap ring 40 is provided on the inner wall surface of the external opening 32 of the through hole 30.

  FIG. 3 is a perspective view showing the valve body 36. The valve body 36 is made of a hard resin or the like, preferably has a rigidity that is difficult to be deformed by water pressure, and is made of a material that is lightweight and desirably has a specific gravity smaller than that of water. The valve body 36 is formed in a substantially cylindrical shape having a diameter with an appropriate gap for forming a communication path 41 between the inner wall surface of the external opening 32 of the through hole 30 formed in the housing 22 and passing through. The hole 30 is accommodated on the external opening 32 side. The upper surface of the valve body 36 can be moved by an external pressure such as water pressure until it comes into close contact with the annular sealing material 38 provided on the step surface 56 of the through hole 30 with respect to the central axis direction of the through hole 30. The communication path 42 is closed between the upper surface of 36 and the annular sealing material 38. Note that the upper surface of the valve body 36 does not necessarily have to be a flat surface, as long as the communication path 42 is closed by the close contact between the annular seal member 38 and the valve body 36. For example, the upper surface of the valve body 36 is centered. If the structure is raised, the oil leaking into the housing 22 can be discharged to the outside more quickly.

  The valve body 36 includes an annular outer peripheral groove 52 having a groove bottom diameter smaller than the outer diameter of the valve body 36 at the upper portion of the outer peripheral surface. That is, an annular outer peripheral groove 52 that circulates around the outer peripheral surface of the valve body 36 is provided. The seal ring 48 accommodated in the annular outer peripheral groove 52 is made of, for example, a soft resin such as synthetic rubber, and can be moved or expanded by water pressure. The outer diameter of the seal ring 48 is smaller than the hole diameter of the external opening 32 and larger than the outer diameter of the valve body 36, and the inner diameter of the seal ring 48 is larger than the groove bottom diameter of the annular outer circumferential groove 52. The outer diameter of 36 is smaller, and the thickness of the seal ring 48 is smaller than the groove width of the annular outer circumferential groove 52 on the outer circumferential surface of the valve body 36. That is, the seal ring 48 has a gap with the inner wall of the through hole 30 and is annular in a state in which the seal ring 48 can slide in the vertical direction by the gap between the groove width of the annular outer circumferential groove 52 and the thickness of the seal ring 48. It is accommodated in the outer peripheral groove 52. Further, the gap due to the difference between the groove width of the annular outer circumferential groove 52 and the thickness of the seal ring 48 is formed larger than the gap between the seal ring 48 and the inner wall of the external opening 32.

  In the external opening 32 of the through hole 30, a disk-like filter 44 having fine communication holes for removing foreign matters such as mud and sand is attached to the housing 22 so as to close it in the external opening 32. It is provided by being hooked to a fixed snap ring 40. Since the valve body 36 falls due to gravity only by fitting the valve body 36 into the through hole 30, the snap ring 40 supports the valve body 36 via the filter 44 and prevents natural fall. The filter 44 may be formed integrally with the valve body 36. The snap ring 40 that urges the valve body 36 downward is provided with a spring 46 between the valve body 36 and the stepped surface 56, and usually between the valve body 36 and the annular seal member 38 by the reaction force of the spring 46. A communication path 42 is formed. The spring 46 may not be connected to the valve body 36 and the step surface 56. The spring 46 may be configured to suspend the valve body 36. In this case, it is possible to prevent vibrations applied to the valve body 36 during traveling and to prevent the valve body 36 from dropping in a configuration that does not include the snap ring 40 and the filter 44.

  Next, the operation of the second breather 28 will be described with reference to FIGS.

  As shown in FIG. 4, the valve body 36 of the second breather 28 is supported by a filter 44 and a spring 46 in a normal state. The seal ring 48 is seated on the lower surface side of the annular outer circumferential groove 52. In this state, gaps are formed between the upper surface of the valve body 36 and the annular seal member 38, and between the through hole 30 and the seal ring 48. As a result, the inside and outside of the housing 22 communicate with each other, and the communication path 42 is opened, and ventilation and oil leaking into the housing 22 can be discharged to the outside.

  On the other hand, when water is jetted toward the second breather 28 due to traveling on a puddle road surface, the seal ring 48 provided on the valve body 36 is first pushed upward according to the water pressure as shown in FIG. It is. Then, the gap between the seal ring 48 and the lower surface side in the annular outer circumferential groove 52 becomes wider than the gap between the seal ring 48 and the external opening 32, and water enters the annular outer circumferential groove 52. Next, the seal ring 48 is expanded and deformed from the inside to the outside by the water pressure of the water that has entered the annular outer circumferential groove 52, and the communication path 41 is blocked by the water pressure that pushes upward. The arrows around the seal ring 48 in FIG. 5 indicate that the seal ring 48 is subjected to water pressure. Further, when a differential pressure is generated between the inside and the outside of the air chamber 20 due to the blockage with the outside, the valve body 36 having a relatively large area has a relatively large upward thrust based on the differential pressure. Works. That is, when the water pressure indicated by the arrow at the bottom of the valve body 36 in FIG. 6 is larger than the biasing force of the spring 46, the seal ring 48 is pushed upward together with the valve body 36 by the water pressure, and the valve body 36 and the annular seal member 38 are moved. Closely contact the communication path 42 to prevent the inflow of water promptly and reliably. When the seal ring 48 is not subjected to water pressure, the valve body 36 and the seal ring 48 are returned to the normal position shown in FIG. 4 by the reaction force of the spring 46 and the weight of the valve body 36, and the communication paths 41 and 42 are opened again. The state shown in FIG. 4 is obtained.

  Even when a water pressure that balances the pressure in the housing 22 is generated, the communication paths 41 and 42 are closed by the seal ring 48 and the communication between the inside and outside of the air chamber 20 is blocked. Furthermore, a differential pressure is generated inside and outside the housing 22, and the valve body 36 is reliably closed.

  According to the vehicle power transmission device of the present embodiment, the first breather 27 is provided at the upper portion of the case 26, and the second breather 28 is provided at the lower portion, that is, the bottom portion of the housing 22. In this way, the pressure in the case 26 is released by the first breather 27, so that the oil in the case 26 is suppressed from leaking into the housing 22 through the annular seal member 38. In addition, the inside and outside of the housing 22 are normally ventilated by the second breather 28, and oil leaking into the housing 22 is discharged to the outside. On the other hand, when water flows in from the outside, the valve body 36 that blocks communication between the inside and outside of the housing 22 by water buoyancy or water pressure suppresses the inflow of water into the housing 22. Therefore, it is possible to perform ventilation inside and outside the housing 22, discharging oil leaking into the housing 22, and preventing water from flowing into the housing 22 from the outside without increasing the number of discharge ports. .

  Further, according to the vehicle power transmission device of the present embodiment, the valve body 36 has a substantially cylindrical shape having an outer diameter smaller than that of the through hole 30 and has a groove bottom diameter smaller than the outer diameter of the valve body 36. An annular outer circumferential groove 52 is provided on the outer circumferential surface, and the annular outer circumferential groove 52 accommodates a seal ring 48. The outer diameter of the seal ring 48 is smaller than the hole diameter of the through hole 30 and larger than the outer diameter of the valve body 36. The thickness of the seal ring 48 is smaller than the groove width of the annular outer peripheral groove on the outer peripheral surface of the valve body 36. In this way, normally, a communication path that communicates the inside and outside of the housing 22 is formed by the gap between the inner wall of the through hole 30 and the valve body 36, and the inside and outside of the housing 22 are ventilated, and leakage into the housing 22 occurs. The oil is discharged. When the vehicle travels in the water pool, the seal ring 48 is levitated by water pressure, water enters the annular outer circumferential groove 52 of the valve body 36, and the seal ring 48 is expanded and deformed from the inside by the entering water, so that the communication path Therefore, the inflow of water into the air chamber is suppressed.

  Further, according to the vehicle power transmission device of the present embodiment, the gap due to the difference between the groove width and the thickness of the seal ring 48 is larger than the gap due to the difference between the hole diameter of the through hole 30 and the outer diameter of the seal ring 48. Is bigger. In this way, water can easily enter the annular outer circumferential groove 52 of the valve body 36, so that the seal ring 48 is expanded and deformed to easily block the communication path, and the inflow of water into the housing 22 is more reliably suppressed. Is done.

  Further, according to the vehicle power transmission device of the present embodiment, the valve body 36 is accommodated on the external opening side of the through hole 30, and the inside and outside of the housing 22 are communicated between the valve body 36 and the annular seal member 38. A clearance is provided, and the valve body 36 is movable in a direction to close the clearance until the valve body 36 comes into close contact with the annular sealing material 38. In this way, normally, a communication path is formed by the gap between the annular seal member 38 and the valve body 36, and the oil leaking into the air chamber is discharged while ventilating the outside of the air chamber. When the water pressure is applied from the outside, the valve body 36 is moved upward, and is brought into close contact with the annular seal member 38 to close the communication path, so that the inflow of water into the housing 22 is reliably suppressed.

  Further, according to the vehicle power transmission device of the present embodiment, the spring 46 is provided between the upper surface of the valve body 36 and the step surface 56. In this way, when water pressure is not applied from the outside, a communication path is formed between the valve body 36 and the annular seal member 38 by the reaction force of the spring 46, so that ventilation is reliably performed without applying water pressure. Can do.

  Further, according to the vehicle power transmission device of the present embodiment, the through hole 30 includes the filter 44 at the external opening thereof. By doing so, the filter 44 suppresses the entry of foreign matter, so that damage to the valve body 36 and the seal ring 48 is suppressed.

  As mentioned above, although one Example of this invention was described in detail with reference to drawings, this invention is not limited to this Example, It can implement in another aspect.

  The first breather may be a breather having a function of adjusting the pressure in the case. For example, the first breather may be an open air breather in which the inside and outside are always in communication.

  Moreover, the structure provided with the some 2nd breather 28 with respect to the housing 22 may be sufficient, and each 2nd breather 28 does not necessarily need to be the same shape. By providing a plurality of second breathers 28 in the housing, the oil in the air chamber 20 is easily discharged.

  It should be noted that the above description is merely an embodiment, and other examples are not illustrated, but the present invention can be implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the gist thereof. it can.

12: Electric motor 20: Air chamber 22: Housing 24: Oil chamber 26: Case 28: Second breather 30: Through hole 36: Valve body 38: Annular seal material 40: Snap ring 42: Communication path 44: Filter 48: Seal ring

Claims (6)

An oil chamber case in which the transmission is accommodated and oil is accommodated therein; and an interior in which the electric motor is accommodated includes an air chamber housing;
The case and the housing are arranged adjacent to each other, and are a vehicle power transmission device in which an input shaft of the transmission and an output shaft of the electric motor are connected,
A first breather that is provided at an upper portion of the case and adjusts an internal pressure of the case;
A valve body is provided at a lower part of the housing and normally communicates with the inside and outside of the housing, and shuts off the communication between the inside and outside of the housing by water buoyancy or water pressure biased from the outside of the housing toward the inside of the housing. With 2 breathers,
A power transmission device for a vehicle. The second breather is constituted by a through hole communicating with the inside and outside of the housing, and a valve body accommodated in the through hole,
The through hole is substantially cylindrical,
The valve body has a substantially cylindrical shape with an outer diameter smaller than the diameter of the through hole, and has an outer circumferential surface with an annular outer circumferential groove having a groove bottom diameter smaller than the outer diameter of the valve body,
A seal ring is accommodated in the annular outer circumferential groove, and an outer diameter of the seal ring is smaller than a hole diameter of the through hole and larger than an outer diameter of the valve body, and an inner diameter of the seal ring is a groove of the annular outer circumferential groove. Larger than the bottom diameter, the thickness of the seal ring is smaller than the groove width of the annular outer peripheral groove on the outer peripheral surface of the valve body,
The power transmission device for a vehicle according to claim 1. The gap due to the difference between the groove width and the thickness of the seal ring is larger than the gap due to the difference between the hole diameter of the through hole and the outer diameter of the seal ring,
The vehicle power transmission device according to claim 2. The through hole has a larger hole diameter of an external opening that opens to the outside of the housing than an internal opening that opens to the inside of the housing.
In the through hole, having an annular step surface due to a difference in the hole diameter of the external opening and the internal opening,
An annular sealing material is provided on the step surface,
The valve body is accommodated on the outer opening side of the through hole, and includes a gap communicating between the inside and outside of the housing between the valve body and the annular seal member, and the valve body is in the direction of closing the gap. Being movable until it is in close contact with the material,
The power transmission device for a vehicle according to any one of claims 2 to 3. Comprising an elastic body between the upper surface of the valve body and the step surface;
The power transmission device for a vehicle according to claim 4. Providing a filter in the external opening of the through hole;
The power transmission device for a vehicle according to any one of claims 1 to 5.

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