JP2016025717A - Motor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor unit capable of suppressing the transfer of heat from a motor chamber to an inverter chamber while communicating the motor chamber and the inverter chamber and regulating internal pressures in both the chambers.SOLUTION: The motor unit includes: a motor chamber 17 in which a motor 3 is accommodated; and an inverter chamber 16 which is separated from the motor chamber 17 by a partition wall 13 and in which an inverter 2 for controlling electrification to a stator coil 34 is accommodated. The motor chamber 17 includes a communication path 14d as an outside air communication part for inner pressure regulation communicating with outside air, an area breather chamber 18a and an air breather pipe 19. A through-hole 13a for rotary shaft support as a rotor shaft supporting part for supporting a rotor shaft 31 of the motor 3 is provided while penetrating the partition wall 13. The motor unit also includes an air circulation part 80 which communicates the inverter chamber 16 and the motor chamber 17 through the inside of the through-hole 13a for rotor shaft support penetrating the partition wall 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor unit that houses an inverter and a motor.

2. Description of the Related Art Conventionally, a terminal box that controls driving of a motor is adjacently arranged in the axial direction of a motor case (see, for example, Patent Document 1).
In this prior art, the terminal box is communicated with the motor case, and the internal pressure adjusting means communicating with the outside air is provided in the terminal box containing the configuration for energization control so that the internal pressure in the motor case can be adjusted.

JP 2009-214729 A

  However, in the above-described prior art, the motor chamber and the terminal box that accommodates the configuration for energization control are communicated by the wiring circuit of the conductive member, and the internal pressure adjusting means is provided in the terminal box. For this reason, there has been a problem that heat generated by the coil on the motor side is transmitted to an energization control circuit in the terminal box and is affected by heat.

  The present invention has been made paying attention to the above-mentioned problem, and suppresses the transfer of heat from the motor chamber to the inverter chamber while allowing the motor chamber and the inverter chamber to communicate to adjust the internal pressure of both chambers. It is an object of the present invention to provide a motor unit that can be used.

In order to achieve the above object, the present invention provides:
In the motor chamber that houses the motor, an outside air communication part for adjusting the internal pressure that communicates with the outside air is provided,
A rotor shaft support portion for supporting the rotor shaft is provided through the partition;
The motor unit is characterized in that an air circulation portion is provided that communicates the inverter chamber and the motor chamber through the inside of the rotor shaft support portion that penetrates the partition wall.

In the motor unit of the present invention, the air in the motor chamber is sucked and discharged to the outside air side by the outside air communication portion to adjust the internal pressure of the motor chamber. Therefore, since the high-temperature air in the motor chamber is not sucked or discharged via the inverter chamber, the inverter can be protected from the high temperature of the motor.
Further, the air in the inverter chamber is sucked into and discharged from the motor chamber through the air flow passage that connects the two chambers through the inside of the rotor shaft support portion that penetrates the partition wall, and the internal pressure is adjusted together with the motor chamber. Since this rotor shaft support part is separated from the drive part which becomes high temperature of the motor and is relatively low temperature, it is possible to suppress the thermal influence on the inverter of the motor via the air flow passage provided in this part.

FIG. 2 is a cross-sectional view showing the overall configuration of the motor unit according to the first embodiment. FIG. 6 is a cross-sectional view showing an overall configuration of a motor unit according to a second embodiment. FIG. 6 is a cross-sectional view illustrating an overall configuration of a motor unit according to a third embodiment.

Hereinafter, the best mode for realizing the motor unit of the present invention will be described based on the embodiments shown in the drawings.
(Embodiment 1)

First, the configuration of the motor unit according to the first embodiment will be described.
[Overall configuration of motor unit]
FIG. 1 shows a motor unit A according to Embodiment 1, and the overall configuration of the motor unit A will be described below with reference to FIG. The motor unit A is a so-called in-wheel type motor unit connected to a vehicle suspension device in order to drive the front wheels of the vehicle (not shown).

  The motor unit A includes a unit case 1, an inverter 2, a motor / generator (hereinafter simply referred to as a motor) 3, a parallel shaft gear pair 4, a planetary gear reduction mechanism 5, and a tire shaft 6. Yes. The motor shaft center line CLm of the rotor shaft 31 of the motor 3 is offset from the tire shaft center line CLt of the tire shaft 6 above the vehicle (in the direction of the arrow UP in FIG. 1).

[Unit case structure]
The unit case 1 is supported via a knuckle arm 71 so as to be steerable with respect to a vehicle body not shown. This unit case 1 includes an inverter cover (inverter housing member) 11, an inverter case (inverter housing member) 12, a partition wall 13, a motor case (motor housing member) 14, and a speed reducer case 15 that are bolted together. Configured.
The inside of the unit case 1 is partitioned into an inverter chamber 16, a motor chamber 17, and a reduction gear chamber 18.

  The motor case 14 has a cylindrical portion 14 b that surrounds the outer periphery of the motor 3. A motor chamber 17 is formed by closing the opening portion of the cylindrical portion 14 b of the motor case 14 in the vehicle interior direction (arrow IN direction) with the partition wall 13. In the drawing, an arrow OUT indicates the vehicle outer direction in the vehicle width direction (axial direction).

The inverter cover 11 and the inverter case 12 form an inverter chamber 16 that houses the inverter 2 adjacent to each other in the vehicle interior direction in the axial direction of the motor chamber 17, and both chambers 16 and 17 are axially separated by the partition wall 13. It is divided into. In the figure, the arrow IN indicates the vehicle inner side in the vehicle width direction, and the arrow OUT indicates the vehicle outer side in the vehicle width direction.
Further, the inverter case 12 is formed in a cylindrical shape that is continuous with the cylindrical portion 14 b of the motor case 14, and the inverter inner side of the inverter case 12 is closed by the inverter cover 11. In addition, a terminal connection portion 12b for connecting the inverter 2 and a power source (not shown) is provided on the upper portion of the inverter case 12.

  The speed reducer case 15 accommodates and supports the parallel shaft gear pair 4 and the planetary gear speed reduction mechanism 5 constituting the speed reduction mechanism, and supports the tire shaft 6.

The inverter chamber 16 and the motor chamber 17 described above are dry spaces.
On the other hand, the speed reducer chamber 18 is a wet space in which oil for lubrication and cooling is accommodated. In addition, an oil storage portion 44 that stores oil dropped due to gravity is provided at the lower portion of the speed reducer chamber 18.
Further, in the unit case 1, radiating fins 11 a and 14 a that are cooled by running air are provided on the outer peripheral surfaces of the inverter cover 11 and the motor case 14, respectively.

  The knuckle arm 71 is fixed to the speed reducer case 15. The knuckle arm 71 is connected at its lower end to a lower arm (not shown), and at its upper end, an upper arm (not shown) is connected. Support.

[Inverter, motor, reduction mechanism]
Below, the inverter 2, the motor 3, and the deceleration mechanism are demonstrated.
The inverter 2 includes a plurality of switch elements that are connected to a power source (not shown) and that form a multi-phase alternating current. Further, by including such a switch element, the heat resistance of the inverter 2 is relatively lower than the heat resistance of the motor 3.

The motor 3 includes a rotor shaft 31, a rotor core 32, a stator 33, and a stator coil 34.
The rotor shaft 31 is rotatably supported with respect to the partition wall 13 and the motor case 14 by bearings 35 and 36. That is, the partition wall 13 is formed with a rotor shaft support through hole 13a as a rotor shaft support portion coaxially with the motor shaft center line CLm, and a bearing 35 provided on the inner periphery of the rotor shaft support through hole 13a. One end of the rotor shaft 31 is supported.

  The end of the rotor shaft 31 on the speed reduction mechanism side protrudes into the speed reducer chamber 18, and a support hole 31 d is formed along the shaft center from the tip of the rotor shaft 31. The support hole 31 d is formed in the speed reducer case 15. A fixed support retainer 38 is inserted. A bearing 36 is interposed between the support retainer 38 and the support hole 31d.

The rotor core 32 is fixed to the outer periphery of the rotor shaft 31 and is composed of a laminated steel plate in which a permanent magnet is embedded.
The stator 33 is fixed to the motor case 14, is disposed via the rotor core 32 and an air gap, and is configured by a laminated stator tooth around which the stator coil 34 is wound.

That is, the motor 3 can rotate (powering) the rotor shaft 31 by applying a multi-phase alternating current such as a three-phase current to the stator coil 34, while the rotation of the rotor shaft 31 causes the stator coil 34 to have a plurality of phases. An alternating current can be generated (regeneration). Therefore, the inverter 2 and the stator coil 34 are connected via the connection hole 13d formed through the upper part of the partition wall 13.
Further, the connecting hole 13d partitions the inverter chamber 16 and the motor chamber 17 in a state in which the sealing member 13e keeps hermeticity and cuts off heat.
A resolver 37 for detecting the motor rotation angle is provided at the end position of the rotor shaft 31 on the inverter 2 side. The resolver 37 is supported by a resolver case 39 having a hat cross-sectional shape fixed to the partition wall 13.

  As shown in the drawing, the rotor shaft 31 includes a small-diameter portion 31a having a relatively small diameter at one end portion on the inverter 2 side as compared with other portions. Further, the rotor core fixing portion 31b for fixing the rotor core 32 in the central portion in the axial direction of the rotor shaft 31 is formed to have a relatively larger diameter than the small diameter portion 31a. Further, in the rotor shaft 31, in order to form a step portion that abuts the rotor core 32 in the axial direction, the rotor core 31 is formed in a larger diameter than the rotor core fixing portion 31b adjacent to the speed reduction mechanism side in the axial direction of the rotor core fixing portion 31b. A large diameter portion 31c is formed. An oil seal 63 that seals the motor chamber 17 and the reduction gear chamber 18 is provided between the large diameter portion 31 c and the motor case 14.

Furthermore, the tip of the small-diameter portion 31a that is one end portion of the rotor shaft 31 passes through the partition wall 13 through the rotor shaft support through hole 13a provided in the partition wall 13 and faces the inverter chamber 16. Yes.
And in this Embodiment 1, the front-end | tip part of the small diameter part 31a of the rotor shaft 31 is arrange | positioned adjacent to the board | substrate 2a of the inverter 2. FIG.

Next, the parallel shaft gear pair 4 and the planetary gear reduction mechanism 5 which are reduction mechanisms will be described.
The parallel shaft gear pair 4 transmits the rotation of the rotor shaft 31 of the motor 3 with respect to the tire shaft 6 to the planetary gear reduction mechanism 5 that performs the first-stage deceleration and performs the second-stage deceleration. The speed reduction mechanism 5 transmits the reduced speed rotation to the tire shaft 6.

  The parallel shaft gear pair 4 includes an input gear 41 formed at the end of the rotor shaft 31, an output gear 42 that meshes with the input gear 41 and has a larger diameter than the input gear 41, and an output gear that integrally includes the output gear 42. And a reduction gear having a shaft 43. The output gear 42 is disposed so as to be partly immersed in oil in the oil reservoir 44 formed at a position below the tire axis center line CLt in the unit case 1.

  The output gear shaft 43 is rotatably supported at the motor side shaft end portion via the bearing 45 with respect to the motor case 14, and the wheel side shaft end portion is rotatably supported at the tire shaft 6 via the bearing 46. . The output gear shaft 43 is formed with a through-shaft oil passage 47 at the axial center position.

  The planetary gear reduction mechanism 5 is disposed in the reduction gear chamber 18 at a position on the reduction gear case 15 side of the parallel shaft gear pair 4. The planetary gear reduction mechanism 5 is engaged with the output gear shaft 43, a plurality of pinions 52 that mesh with the sun gear 51, a pinion carrier 53 that supports the pinion 52, and meshes with the pinion 52 and is fixed to the speed reducer case 15. Ring gear 54. That is, the planetary gear reduction mechanism 5 is a reduction gear mechanism that reduces the input rotation from the sun gear 51 and outputs it to the pinion carrier 53 by fixing the ring gear 54 to the case. The rotation center axis of the planetary gear speed reduction mechanism 5 is coaxial with the output gear 42 and the rotation center axis of the tire shaft 6 (tire axis center line CLt).

The tire shaft 6 is a unit output shaft that is formed integrally with the pinion carrier 53 of the planetary gear speed reduction mechanism 5 and has a shaft end projecting from the speed reducer case 15 to the outside in the direction of the arrow OUT that is the vehicle outward direction.
One end portion of the tire shaft 6 on the planetary gear speed reduction mechanism 5 side is rotatably supported by a reduction gear case 15 by a bearing 61 and a mechanical seal 62 in an oil-tight state. A wheel hub shaft 72 is serrated to the other end of the tire shaft 6 that protrudes outside the unit. The wheel hub shaft 72 is rotatably supported by a hub bearing 74 having a double-row angular bearing structure with respect to a knuckle case 73 bolted to the knuckle arm 71.

[Internal pressure adjustment structure]
In the first embodiment, the motor chamber 17 and the inverter chamber 16 that are dry spaces have a structure that adjusts the internal pressure so as to communicate with the outside air and maintain the atmospheric pressure.

First, the communication structure with the atmosphere will be described.
An air breather chamber 18 a is formed in the upper part of the speed reducer chamber 18. The air breather chamber 18a is connected to an air breather pipe 19 communicated with the atmosphere. As is well known, the air breather pipe 19 includes a filter that allows only air to flow and restricts the ingress of dust and moisture.

The air breather chamber 18a communicates with the motor chamber 17 via a communication passage 14d. That is, the motor chamber 17 is communicated with the outside air via the communication passage 14d as the outside air communication portion, the air breather chamber 18a, and the air breather pipe 19.
The air breather chamber 18a communicates with the speed reducer chamber 18 through a labyrinth structure (not shown) while maintaining communication and preventing oil from entering. Is also in communication with the atmosphere.
Further, as will be described in detail later, the inverter chamber 16 communicates with the motor chamber 17 and communicates with the outside air via the motor chamber 17, the communication passage 14d, the air breather chamber 18a, and the air breather pipe 19.

  Therefore, the inverter chamber 16, the motor chamber 17, and the reduction gear chamber 18 are each connected to the outside air, and when the internal pressure fluctuates due to the influence of heat or the volume variation of the internal oil, the outside and the air are sucked and discharged. The internal pressure is adjusted so as to keep the internal pressure at approximately atmospheric pressure.

Next, a communication structure between the inverter chamber 16 and the motor chamber 17 will be described.
The inverter chamber 16 is communicated using a rotor shaft support through hole 13 a formed through the partition wall 13.
That is, a ball bearing is used as the bearing 35 interposed between the small-diameter portion 31a of the rotor shaft 31 and the rotor shaft support through hole 13a, and the air in the axial direction indicated by the arrow Wa is interposed between the ball bearings. There is a gap (not shown) that enables the distribution of
The resolver 37 interposed between the tip of the small diameter portion 31a of the rotor shaft 31 and the resolver case 39 also has an axial gap (not shown) that allows air to flow as indicated by the arrow Wb. doing.

  Therefore, the inverter chamber 16 and the motor chamber 17 allow air to flow with a gap (not shown) provided between the rotor shaft 31 and the rotor shaft support through hole 13a as an air flow portion 80.

(Operation of Embodiment 1)
Below, the effect | action of the motor unit of Embodiment 1 is demonstrated.
In the unit case 1, the motor chamber 17, which is a dry space, is communicated with the atmosphere via a communication path 14 d, an air breather chamber 18 a, and an air breather pipe 19. Therefore, when a pressure change occurs in the motor chamber 17 due to heat generation of the motor 3 or cooling after driving, the air can be sucked and discharged from the outside by the air flow indicated by the arrow Wc and can be maintained at the atmospheric pressure.

Even in the inverter 2 housed in the inverter chamber 16, heat is generated with the drive, so that the internal pressure changes even in the inverter chamber 16. In this case, when a pressure difference is generated between the inverter chamber 16 and the motor chamber 17, the air in the inverter chamber 16 is provided between the rotor shaft 31 and the rotor shaft support through hole 13a as indicated by arrows Wa and Wb. It circulates through the air circulation part 80. Therefore, the inverter chamber 16 can be maintained at the same pressure as the motor chamber 17, that is, atmospheric pressure.
Further, in this way, when the inverter chamber 16 and the motor chamber 17 are kept at atmospheric pressure, the air breather structure that communicates the inside of the unit case 1 with the outside air is installed at only one location. For this reason, compared with what provided this air breather structure in each of the inverter chamber 16 and the motor chamber 17, the number of parts and installation space can be reduced.

Next, the thermal effect accompanying the above air flow will be described.
As described above, the air that has become hot in the inverter chamber 16 flows into the motor chamber 17 as the air in and out of the chambers 16 and 17 is sucked and discharged. However, in this case, since the heat resistance of the motor 3 is set higher than the heat resistance of the inverter 2, the heat on the inverter chamber 16 side does not adversely affect the motor 3 in the normal operation range of the inverter 2. .

On the other hand, the air circulation part 80 is provided in the vicinity of the outer periphery of the rotor shaft 31 and is arranged radially away from the stator coil 34 that becomes high temperature. For this reason, contrary to the above, when the air that has become hot in the motor chamber 17 flows into the inverter chamber 16, the hottest air in the motor chamber 17 is unlikely to flow into the inverter chamber 16, and the heat enters the inverter 2. An adverse effect can be suppressed.
When the vehicle 2 travels, when the inverter 2 and the motor 3 generate heat by driving, the inverter cover 11, the inverter case 12, and the motor case 14 basically perform cooling by radiating heat. In this case, heat dissipation fins 11a and 14a are formed in the inverter cover 11 and the motor case 14, and can be efficiently cooled by the traveling wind.

(Effect of Embodiment 1)
The effects of the motor unit according to the first embodiment are listed below.
1) The motor unit of the first embodiment is
A motor case 14 as a motor housing member that forms a motor chamber 17 that houses the motor 3;
As an inverter housing member that forms an inverter chamber 16 that is arranged adjacent to the motor chamber 17 in the axial direction and that is partitioned by the motor chamber 17 and the partition wall 13 and houses the inverter 2 that controls energization to the stator coil 34. Inverter cover 11 and inverter case 12,
A motor unit comprising:
The motor chamber 17 is provided with a communication passage 14d as an outside air communication portion for adjusting internal pressure communicating with outside air, an air breather chamber 18a, and an air breather pipe 19.
A rotor shaft support through hole 13a as a rotor shaft support portion for supporting the rotor shaft 31 of the motor 3 is provided through the partition wall 13,
An air circulation portion 80 is provided that communicates between the inverter chamber 16 and the motor chamber 17 through the inside of the rotor shaft support through hole 13a penetrating the partition wall 13.
Therefore, in the motor unit, when adjusting the internal pressure of the inverter chamber 16 and the motor chamber 17, the air in the motor chamber 17 is sucked and discharged to the outside air side by the communication passage 14d as the outside air communication portion, the air breather chamber 18a, and the air breather pipe 19. .
Since the heat of the motor 3 that may be higher than that of the inverter 2 due to the difference in heat resistance is not absorbed or exhausted via the inverter chamber 16 during the internal pressure adjustment, the inverter 2 is heated to a high temperature. Can be protected from.
In addition, when adjusting the internal pressure, the inverter chamber 16 is sucked into and discharged from the motor chamber 17 by the air circulation unit 80, and the internal pressure is adjusted together with the motor chamber 17 using a communication portion with the outside air in the motor chamber 17.
Since the heat resistance of the inverter 2 is set lower than the heat resistance of the motor 3, even if high-temperature air in the inverter chamber 16 flows into the motor chamber 17 via the air circulation unit 80, the influence on the motor 3 is not affected. small.
On the other hand, when the air in the motor chamber 17 flows into the inverter chamber 16 from the air circulation portion 80, the inner side of the rotor shaft support through hole 13 a provided with the air circulation portion 80 is a drive portion that becomes a high temperature of the motor 3. It is away from a certain stator coil 34 and has a relatively low temperature. For this reason, when the air of the motor chamber 17 flows into the inverter chamber 16, the possibility that the high-temperature air around the stator coil 34 flows is low, and the thermal influence on the inverter 2 due to this high temperature can be suppressed.

2) The motor unit of the first embodiment is
The motor 3 includes a stator coil 34 that generates a rotational force in the rotor shaft 31 by energization at a position in the outer diameter direction than the rotor shaft 31;
The partition wall 13 divides the inverter chamber 16 and the motor chamber 17 at a position overlapping the stator coil 34 in the radial direction.
In the first embodiment, the connection hole 13d formed in this part is closed by the seal member 13e, and is partitioned in a state where the airtightness and heat are blocked.
Therefore, the air flow portion 80 is formed in the partition wall 13 so that the air in the inverter chamber 16 is sucked into and discharged from the motor chamber 17, but against the heat at the axial end of the stator coil 34 that generates a large amount of heat in the motor 3. Thus, heat can be reliably shielded by the partition wall 13.
Thereby, the thermal influence of the motor 3 stator coil 34 with respect to the inverter 2 can be suppressed.

3) The motor unit of the first embodiment is
A gap that passes through the air flowing portion 80 in the axial direction through a bearing 35 interposed between the inner periphery of the rotor shaft supporting through hole 13a and the outer periphery of the small diameter portion 31a of the rotor shaft 31, and the small diameter portion 31a It is characterized in that it is formed using a gap penetrating in the axial direction in a resolver 37 attached to the outer periphery.
Therefore, the air circulation part 80 can be formed without adding new parts or adding processing, which is economically superior.

4) The motor unit of the first embodiment is
The heat resistance of the motor 3 is set higher than the heat resistance of the inverter 2.
Therefore, even if the air that has absorbed the heat of the inverter 2 flows into the motor chamber 17 as in 1) above, the motor 3 can be prevented from being adversely affected by the heat.

(Other embodiments)
Next, a motor unit according to another embodiment will be described.
In the description of the other embodiments, the same reference numerals as those in the first embodiment are assigned to the same components as those in the first embodiment, and the description thereof is omitted. Only the differences from the first embodiment will be described. .

(Embodiment 2)
Below, the motor unit of Embodiment 2 is demonstrated based on FIG.
The motor unit of the second embodiment is an example in which a through-hole 280 as an air flow passage that communicates the inverter chamber 16 and the motor chamber 17 is formed in the rotor shaft 231.
That is, as shown in FIG. 2, the rotor shaft 231 having the through hole 280 penetrates the partition wall 13 and faces the inverter chamber 16, and further passes the small diameter portion 31a through the substrate 2a of the inverter 2, The tip is disposed close to the inverter cover 11.

A through hole 280 formed in the rotor shaft 231 is formed by communicating an axial hole 281 and a radial hole 282.
The axial hole 281 extends in the axial direction from a through-hole inlet 281 a opened at the tip of the small diameter portion 31 a of the rotor shaft 231 to the position of the rotor core fixing portion 31 b of the rotor shaft 231. The through-hole inlet 281a is disposed close to and opposite to the inverter cover 11, and based on this arrangement, the air indicated by the arrow Wb flowing through the through-hole 280 and entering and exiting the through-hole inlet 281a Heat exchange with the inverter cover 11 is possible.

  The radial hole 282 is connected to a through hole outlet 282a opened in the motor chamber 17 in the rotor core fixing portion 31b from the position of the distal end portion of the axial hole 281 in the vehicle exterior direction, and is substantially perpendicular to the axial hole 281. It is formed in the radial direction so as to be formed.

  Further, in the second embodiment, a seal member 39 a is interposed between the outer periphery of the small diameter portion 31 a of the rotor shaft 231 and the resolver case 39. Thereby, the flow of air between the inverter chamber 16 and the motor chamber 17 due to the gap of the bearing 35 is blocked.

Next, the operation of the second embodiment will be described.
When the rotor shaft 231 is rotated, in the through-hole 280, a speed difference is generated between the through-hole inlet 281a opened in the axial center and the through-hole outlet 282a opened in the outer periphery of the rotor core fixing portion 31b. As a result, a pressure difference is generated between the through-hole inlet 281a and the through-hole outlet 282a, and an air flow (arrow W2a) from the inverter chamber 16 toward the motor chamber 17 is generated in the through-hole 280.

Therefore, the air in the motor chamber 17 that is likely to be hotter than the inverter chamber 16 is less likely to flow into the inverter chamber 16.
Further, the through-hole inlet 281a is disposed close to the inverter cover 11 that includes the heat radiation fins 11a and cools the inverter chamber 16. For this reason, the high-temperature air that has flowed into the inverter chamber 16 from the motor chamber 17 through the through hole 280 can be cooled by the inverter cover 11 immediately after flowing in.

As described above, the second embodiment has the following effects 2-1) to 2-4) in addition to the effects 1), 2) and 4) described in the first embodiment.
2-1) The motor unit of the second embodiment is
As the air circulation part, the rotor shaft 231 is provided with a through-hole 280 that communicates the inverter chamber 16 and the motor chamber 17.
As described above, the inverter chamber 16 and the motor chamber 17 are communicated with each other through the inside of the rotor shaft 231 so that the air passing through the through hole 280 as the air circulation portion is shielded from the high-temperature air in the motor chamber 17. It becomes possible. For this reason, it becomes possible to further reduce the influence of heat on the inverter 2 due to the air flowing into the inverter chamber 16 from the motor chamber 17.
In addition, in the second embodiment, a seal member 39a is provided between the small-diameter portion 31a of the rotor shaft 231 and the resolver case 39, and between the inner periphery of the rotor shaft supporting through hole 13a and the outer periphery of the small-diameter portion 31a. The air flow was cut off. For this reason, when there is air circulation between the two chambers 16 and 17, the air passes through the through-hole 280, so that the effect of reducing the heat influence can be obtained more reliably.

2-2) The motor unit of the second embodiment is
A small-diameter portion 31a that is an end portion of the rotor shaft 231 on the inverter chamber 16 side is disposed so as to penetrate the partition wall 13 and face the inverter chamber 16.
The through-hole 280 is opened to the small-diameter portion 31a facing the inverter chamber 16, and the through-hole inlet 281a is opened to the motor chamber 17 at a position in the outer diameter direction from the through-hole inlet 281a. The outlet 282a is formed to communicate with each other.
Therefore, when the rotor shaft 231 rotates, a pressure difference is generated between the through-hole inlet / outlet 281a and 282a due to the speed difference between the through-hole inlet 281a and the through-hole outlet 282a, and the motor is supplied from the inverter chamber 16 to the through-hole 280. An air flow toward the chamber 17 is generated. Therefore, the flow of air from the motor chamber 17 that tends to be relatively high temperature to the inverter chamber 16 is suppressed, and the influence of heat on the inverter 2 due to the air flowing from the motor chamber 17 into the inverter chamber 16 is further reduced. It becomes possible to do.

2-3) The motor unit of the second embodiment is
The rotor shaft 231 includes a rotor core fixing portion 31b as a large diameter portion formed larger in diameter than a small diameter portion 31a as an end portion facing the inverter chamber 16, and the through-hole outlet 282a is formed in the rotor core fixing portion 31b. It is provided.
Therefore, the radial distance between the through hole inlet 281a formed in the small diameter part 31a and the through hole outlet 282a formed in the rotor core fixing part 31b can be further ensured. Therefore, the speed difference between the through-hole inlet / outlet 281a and 282a is made larger, and the air in the high-temperature motor chamber 17 is suppressed from flowing into the inverter chamber 16 through the through-hole 280, and the inverter 2 is caused by this inflow. The thermal effect of can be further suppressed.

2-4) The motor unit of Embodiment 2 is
The inverter cover 11 is configured such that heat can be exchanged between the air flowing through the through hole 280 and the inverter cover 11 as the inverter housing member through the through hole inlet 281a opened in the small diameter portion 31a that is the end of the rotor shaft 231. It is characterized by being placed close to.
Therefore, when the high-temperature air in the motor chamber 17 flows into the inverter chamber 16 from the through-hole inlet 281a of the through-hole 280, it can be cooled by the inverter cover 11 and suppressed from having a thermal effect on the inverter 2. it can. In addition, since the inverter cover 11 is provided with the radiation fins 11a, higher cooling performance can be obtained than that without the radiation fins 11a.

(Embodiment 3)
Below, the motor unit of Embodiment 3 is demonstrated based on FIG.
As shown in FIG. 3, the motor unit of the third embodiment forms a refrigerant circulation path 310a in the rotor shaft 331, and a through hole 280 is formed in the vicinity thereof in a partitioned state by the refrigerant circulation path 310a and the partition portion 332e. This is an example. The through hole 280 has the same configuration as that of the second embodiment.

The refrigerant circuit 310a will be described.
The refrigerant circulation path 310a is formed using the support hole 331d of the rotor shaft 331. That is, the support hole 331d is formed deeper in the axial direction than in the first embodiment so that the end on the back side reaches the rotor core fixing portion 31b.

The support retainer 338 has a coolant supply hole 338a formed in the shaft center. Although not described in detail, the coolant supply hole 338a is supplied with oil that has been scraped up in the reduction gear chamber 18 as the speed reduction mechanism rotates.
Furthermore, a flow path forming cylinder member 310 is fitted to the tip of the support retainer 338, and a flow path gap is formed between the outer periphery of the cylindrical member 310 and the inner periphery of the support hole 331d. Is formed.

Therefore, the refrigerant circulation path 310a passes through the inner periphery of the cylindrical member 310 from the refrigerant supply hole 338a and reaches the back of the support hole 331d, and then between the outer periphery of the cylindrical member 310 and the inner periphery of the support hole 331d. As a result, the path passes through the bearing 36 and returns to the reduction gear chamber 18.
As the lubricating oil is circulated through the refrigerant circulation path 310 a, the rotor shaft 331 can be cooled, and the motor 3 such as the rotor core 32 can be cooled via the rotor shaft 331.
In addition, the front end portion on the vehicle inner side in the axial direction of the small-diameter portion 31a of the rotor shaft 331 is disposed close to the inverter cover 11 as in the second embodiment.
Therefore, in the third embodiment, in addition to the operation of the second embodiment described above, the cooling air flowing through the through hole 280 can be cooled by exchanging heat with the lubricating oil circulating in the refrigerant circulation path 310a. Can be obtained.

As described above, the motor unit according to the third embodiment has the effects of 1), 2) and 4) of the first embodiment and the effects of 2-1) to 2-3) of the second embodiment. The following effect 3-1) is achieved.
3-1) The motor unit of Embodiment 3 is
The rotor shaft 331 has a refrigerant circulation path 310a that circulates lubricating oil as a cooling refrigerant and is divided from the through hole 280 inside.
Therefore, the motor chamber 17 can be cooled by circulating the lubricating oil in the speed reducer chamber 18 through the refrigerant circulation path 310a.
Therefore, the rotor shaft 331 can have a communication function between the inverter chamber 16 and the motor chamber 17 by the above-described through-hole 280 and a cooling function of the rotor core 32 of the motor 3 by the refrigerant circulation path 310a.
Moreover, in the third embodiment, since the through hole 280 is disposed close to the refrigerant circulation path 310a and heat exchange is possible between them, the air flowing through the through hole 280 can be cooled by the refrigerant circulation path 310a. it can.

  Although the motor unit of the present invention has been described based on the embodiment, the specific configuration is not limited to this embodiment, and the gist of the invention according to each claim of the claims is described. Unless it deviates, design changes and additions are allowed.

In the embodiment, the motor unit is an in-wheel type that rotates one wheel in the vehicle. However, the motor unit to which the present invention is applied is not limited to this. For example, even when used as a vehicle-mounted drive source, it can also be used for driving both the left and right wheels with one motor unit.
Moreover, although the motor unit of the embodiment has been shown to include a speed reduction mechanism, the motor unit can be applied to a motor torque that is transmitted at the time of output without the speed reduction mechanism interposed. Further, the case where the speed reduction mechanism is provided is not limited to that shown in the embodiment, and for example, only one of the parallel shaft gear pair and the planetary gear speed reduction mechanism may be used. Alternatively, a speed reduction mechanism (for example, a conical gear mechanism) other than the parallel shaft gear pair and the planetary gear speed reduction mechanism may be used.
In the embodiment, the example in which the motor coil is provided in the stator has been described. However, the present invention can also be applied to those provided in the rotor.

In the embodiment, the air circulation part is shown as being provided between the rotor shaft support hole and the rotor shaft, and the air circulation part is provided inside the rotor shaft (through hole). May be added. For example, in the second embodiment, the configuration in which the seal member between the small-diameter portion of the rotor shaft and the resolver case is not provided makes it possible to provide both.
Moreover, the installation positions of the through hole inlet and the through hole outlet are not limited to the positions shown in the embodiment. That is, in the present invention, the through-hole is only required to communicate at least between the inverter chamber and the motor chamber and to allow air to flow between the two and the rotor shaft of the through-hole inlet and the through-hole outlet. As for the position in the radial direction with respect to the shaft center, both may be disposed at the same position, or, contrary to the embodiment, the through hole inlet may be disposed on the outer diameter direction side.

Furthermore, if the through-hole outlet is arranged in the outer diameter direction from the through-hole inlet, an air flow from the inverter chamber to the motor chamber is generated on the rotating shaft of the rotor shaft, and the inverter chamber is less likely to be affected by the heat of the motor chamber. However, the installation position is not limited to the position shown in the embodiment.
For example, the through-hole inlet may be disposed at a position in the outer diameter direction with respect to the axis of the rotor shaft. In this case, the both may be offset in the opposite direction in the radial direction so as not to overlap the refrigerant circulation path in the radial direction. Further, the through hole outlet can be arranged in the large diameter portion in addition to the rotor core fixing portion. In this case, it is possible to increase the radial distance from the through-hole inlet and increase the pressure difference between the through-hole inlet and outlet generated when the rotor rotates.
Or although the number of through-holes was shown only 1 in embodiment, it is also possible to arrange two or more in the position where a circumferential direction differs. Similarly, a plurality of refrigerant circulation paths may be provided.
Further, in the embodiment, the example in which the through hole is provided with the axial hole and the radial hole is shown, but the present invention is not limited to this, and a single straight or curved line is provided from the through hole inlet to the through hole outlet. You may form by a hole.
Moreover, although the rotor shaft showed the example which penetrated the partition through the through-hole for rotor shaft support as a rotor shaft support part in embodiment, it is not limited to this. That is, if the rotor shaft support through hole as the rotor shaft support portion is formed through the partition wall, the rotor shaft can be disposed facing the inverter chamber without passing through the partition wall. Therefore, it is possible to provide the front air circulation part through the inside of the through hole for supporting the rotor shaft.
In addition, although the inverter chamber has a structure in which the inverter cover and the inverter case are provided with heat radiation fins to cool the inverter chamber by heat radiation, the present invention is not limited to this, and a cooling refrigerant may be circulated.

2 Inverter 3 Motor (motor / generator)
11 Inverter cover (inverter housing member)
12 Inverter case (inverter housing member)
13 Partition 13a Rotor shaft support through hole (rotor shaft support)
14 Motor case (motor housing member)
14d Communication passage (outside air communication part)
16 Inverter chamber 17 Motor chamber 18a Air breather chamber (outside air communication section)
19 Air breather pipe (outside air communication part)
31 Rotor shaft 31b Rotor core fixing part (large diameter part)
34 Stator coil (motor coil)
80 Air circulation portion 231 Rotor shaft 280 Through hole 281 Axial hole 281a Through hole inlet 282 Radial hole 282a Through hole outlet 331 Rotor shaft

Claims (7)

A motor housing member forming a motor chamber for housing the motor;
An inverter housing member that is arranged adjacent to the motor chamber in the axial direction and that is partitioned by the motor chamber and a partition, and that forms an inverter chamber that houses an inverter that controls energization of the motor coil;
A motor unit comprising:
In the motor chamber, an outside air communication portion for adjusting internal pressure communicating with outside air is provided,
A rotor shaft support portion for supporting the rotor shaft of the motor is provided through the partition;
A motor unit comprising an air circulation part that communicates the inverter chamber and the motor chamber through the inside of the rotor shaft support that penetrates the partition wall. The motor unit according to claim 1,
The motor unit according to claim 1, wherein a through-hole that communicates the inverter chamber and the motor chamber is provided in the rotor shaft as the air circulation portion. The motor unit according to claim 2,
An end of the rotor shaft on the inverter chamber side is disposed through the partition wall and facing the inverter chamber,
The through-hole is communicated with the through-hole inlet that opens at the end facing the inverter chamber and the through-hole outlet that opens into the motor chamber at a position in the outer diameter direction from the through-hole inlet. A motor unit characterized by being formed. In the motor unit according to claim 3,
The rotor shaft includes a large-diameter portion having a larger diameter than an end facing the inverter chamber, and the through-hole outlet is provided in the large-diameter portion. In the motor unit according to any one of claims 2 to 4,
The motor unit according to claim 1, wherein the rotor shaft has a coolant circulation path for circulating a coolant for cooling partitioned from the through hole. In the motor unit according to any one of claims 2 to 5,
The motor unit characterized in that the through-hole inlet opened at the end of the rotor shaft is disposed close to the inverter housing member so that heat exchange is possible between the air flowing through the through-hole and the inverter housing member. In the motor unit according to any one of claims 1 to 6,
The motor includes a motor coil that generates a rotational force on the rotor shaft by energization at a position in an outer diameter direction than the rotor shaft,
The motor unit, wherein the partition wall partitions the inverter chamber and the motor chamber at a position overlapping the motor coil in the radial direction.