JP2014189036A - Vehicle propulsion unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the cooling performance of a power module of an inverter unit in a device where the inverter unit is attached to an in-wheel motor type motor case.SOLUTION: An inverter unit 3 is attached to a side surface 27 of a motor case 7 which is opposite to an axle 11. An oil for cooling a motor and lubricating a planetary gear 13 is stored in the motor case 7. A power module 25 is disposed in an outer side position of the side surface 27 which corresponds to an oil reservoir 20.

Description

  The present invention relates to a vehicle propulsion device that drives a wheel with an electric motor, and more particularly to an in-wheel motor type vehicle propulsion device in which an electric motor is disposed in the wheel.

  2. Description of the Related Art Conventionally, there is an in-wheel motor type vehicle propulsion device for an electric vehicle, a hybrid vehicle, etc., in which an electric motor is disposed in a wheel and the wheel is directly driven (including through a gear) by the electric motor. Exists.

  There has been proposed an in-wheel motor type vehicle propulsion device in which an inverter unit for driving a motor is disposed in a wheel integrally with an electric motor (see Patent Document 1).

  In general, an inverter unit includes an IGBT element serving as a high-speed switching means and a smoothing capacitor, but the inverter unit, particularly the IGBT element part (power module) is easily affected by heat.

JP 2005-269735 A

  In the above-mentioned Patent Document 1 (see FIGS. 11 to 13), an inverter unit is attached to the outside of a motor case of an electric motor. The power module is provided with a finned heat sink, An embodiment is described in which fins are arranged in a water passage formed in a motor case and the power module is radiated by water cooling.

  Even if the heat dissipation of the power module is ensured, this device becomes a large-scale device such as forming a water channel in the motor case or circulating cooling water through the water channel. It becomes large and expensive.

  Accordingly, the present invention provides a vehicle propulsion device including an in-wheel motor unit that uses the oil in the motor case to cool the power module with a compact and simple configuration, thereby eliminating the above-described problems. It is intended.

For example, referring to FIG. 1 and FIG. 2, the present invention includes a rotor (6) housed in a motor case (7) disposed in a wheel (W) and interlocked with an axle (11) and the motor case. An electric motor (2) having a stator (5) fixed to (7);
In a vehicle propulsion device (1) comprising: an inverter unit (3) electrically connected to the electric motor (2) and having a capacitor (26) and a power module (25) comprising a switching element;
In the motor case (7), oil for lubricating and cooling the electric motor is stored in an oil-tight manner,
On the side surface (27) opposite to the axle (11) of the motor case, the inverter unit is arranged such that the power module (25) is in a position corresponding to the oil sump (20) in the motor case (7). (3) is attached,
This is a vehicle propulsion device.

For example, referring to FIG. 1, a planetary gear (13) that decelerates the rotation of the rotor and transmits it to the axle is interposed between the rotor (6) and the axle (11).
The planetary gear (13) is disposed on the inner diameter side of the rotor so as to at least partially overlap the rotor (6) and the stator (5) in the axial direction when viewed from the radial direction, and is disposed in the motor case (7). It is lubricated with oil.

For example, referring to FIG. 3B, a stator fixing seating surface (40) for supporting the stator (5) is integrally formed on the inner side of the side surface (27) of the motor case (7).
The stator fixing seat surface (40) is opened (D) by notching the oil reservoir (20) side.

  For example, referring to FIG. 4A, a cooling fin (45) is integrally formed at a position corresponding to the power module (25) inside the side surface (27) of the motor case (7). .

  The power module (25) is attached so as to stick directly to the outside of the side surface (27) of the motor case (7).

For example, referring to FIG. 4B, a through hole (46) is formed in a portion corresponding to the power module (25) in the side surface (27) of the motor case (7),
A heat conduction plate (47) made of a material having high heat conductivity is fixed so as to close the through hole, and the power module (25) is attached to the heat conduction plate.

  A heat radiating portion (47a) is integrally provided inside the motor case of the heat conducting plate.

  For example, referring to FIG. 5, a seal member (49) made of a material having low thermal conductivity is interposed between the through hole (46) and the heat conductive plate (47).

  In addition, although the code | symbol in the said parenthesis is for contrast with drawing, it does not affect the structure as described in a claim by this.

  According to the first aspect of the present invention, since the inverter unit is attached to the side surface of the motor case opposite to the axle, the in-wheel type motor unit can be made compact to improve the mountability of the vehicle. The power module of the inverter unit is cooled by the oil in the oil reservoir in the motor case, so that the cooling performance can be secured with a simple and compact configuration.

  According to the second aspect of the present invention, since the rotation of the rotor of the electric motor is decelerated via the planetary gear and transmitted to the axle, the appropriate rotation and torque corresponding to the vehicle are transmitted from the electric motor to the wheels. In addition, since the electric motor and the planetary gear are lubricated by the oil in the motor case, a simple and compact motor unit can be provided.

  According to the third aspect of the present invention, since the stator fixing seat surface of the motor case is opened by notching the oil reservoir side, the heat from the stator is conducted directly from the stator fixing seat surface to the power module. In addition, the rate at which the power module is cooled by the oil reservoir in the motor case can be increased.

  According to the fourth aspect of the present invention, the cooling fins are integrally formed at a position corresponding to the power module inside the side surface of the motor case, so that the cooling efficiency of the power module by the oil can be increased.

  According to the fifth aspect of the present invention, since the power module is attached so as to stick directly to the outside of the side surface of the motor case, a simple configuration such as using the motor case or the like is sufficient.

  According to the sixth aspect of the present invention, the power module mounting portion is configured by embedding a heat conductive plate made of a material having high thermal conductivity, which is a member different from the motor case, so that the power module It can cool efficiently through the conductive plate.

  According to the seventh aspect of the present invention, the heat conducting plate is made of a member different from the motor case, and can easily process the heat radiating portion with high accuracy, and the contact area formed by the high processing. The power module can be efficiently cooled by the large heat radiation part.

  According to the eighth aspect of the present invention, since the seal member is interposed between the through hole of the motor case and the heat radiating plate, the heat transmitted from the electric motor to the motor case is transferred to the seal member having a low thermal conductivity. By shutting off, the cooling performance of the power module can be maintained.

Sectional drawing which shows the vehicle propulsion apparatus by this invention. The side view which shows the inverter unit. It is the side view seen from the mating surface which shows the 2nd case part of a motor case, (A) is what provided the seat surface for stator fixation in the perimeter, and (B) cut and opened the lower side. Embodiments are shown. (A) (B) is a side view which shows a different 2nd case part, respectively. AA sectional view of Drawing 4 (B).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the vehicle propulsion device is an in-wheel type disposed in a wheel W, and is fixed to an arm supported by a suspension device so as to be pivotable in the vertical direction, and is disposed under a spring. A motor unit 1 is included. The motor unit (vehicle propulsion device) 1 includes a motor / generator (rotary electric machine; simply referred to as an electric motor) 2 and an inverter unit 3 for driving the motor. The electric motor 2 includes an IPM motor having a stator 5 in which a coil 5 a is wound around a steel plate and a rotor 6 in which a permanent magnet is embedded, and is housed in a motor case 7.

  The motor case 7 comprises a mating case composed of a first case portion 7a and a second case portion 7b, and is fixed to the arm that is under the spring. A collar 9 and a boss 10 are fixed to the first case portion 7a by bolts, and an axle 11 is supported by the boss 10 via a bearing so as to be freely fixed. A wheel hub 12 is integrally fixed to the axle 11 by a spline and a nut, and the wheel (vehicle) W is mounted on the wheel hub 12. A planetary gear 13 is interposed between the rotor 6 and the axle 11 to decelerate the rotation of the rotor and transmit it to the axle. The planetary gear 13 includes a sun gear S, a ring gear R, and a carrier CR that supports step pinion gears P1 and P2 having two different numbers of teeth.

  The rotor 6 is mounted and fixed on the outer periphery of the flange portion 15a of the drum member 15, and the planetary gear 13 is disposed on the inner diameter side of the flange portion 15a. Accordingly, the planetary gear 13 is disposed on the inner diameter side of the rotor 6 so as to at least partially overlap the rotor 6 and the stator 5 in the axial direction when viewed from the radial direction. At the center of the planetary gear 13, a rotating shaft 16 having the sun gear S is rotatably supported at both ends by the axle 11 and the second case portion 7b via bearings. The drum member 15 on which the rotor 6 is mounted is integrally fixed to the rotary shaft 16. Therefore, the rotary shaft 16 and the axle 11 are arranged in alignment on the same axis and are centered on the same axis. The rotor 6 and the stator 5 are arranged as follows.

  The carrier CR of the planetary gear 13 is connected to the axle 11, and the ring gear R is fixed to a collar 9 integrated with the motor case 7. Therefore, in the planetary gear 13, the rotation of the rotary shaft 16 integral with the rotor 6 is transmitted to the large pinion gear P2, and the small pinion gear P1 meshes with the fixed ring gear R, whereby the carrier CR decelerates and revolves, and the axle 11 is output. The step pinions P1 and P2 arranged on the same axis can obtain different reduction ratios by changing their step ratios.

  A resolver 19 is disposed between the second case portion 7b and the drum member 15. The resolver 19 detects the rotational position (phase) of the rotor 6 and is used for controlling the electric motor. The motor case 7 including the first and second case portions 7a and 7b is configured to be oil-tight, and a predetermined amount of oil is filled therein, and a lower portion of the case 7 serves as an oil reservoir 20. 20a indicates the oil level. An annular member 21 extending in the outer diameter direction is integrally fixed to the tip of the flange portion 15a of the drum member 15, and the tip of the annular member 21 is immersed in the oil reservoir 20 with a blade shape. It is an oil splash piece.

  Therefore, when the electric motor 2 is driven and the rotor 6 rotates, the rotation decelerated via the planetary gear 13 is transmitted to the axle 11 and the wheel (wheel) W is rotated to travel the vehicle. At this time, by the rotation of the rotor 6, the oil splashing piece 21 also rotates integrally, splashing up the oil in the oil reservoir 20, and the oil lubricates and cools the electric motor 2 including the coil 5 a of the stator 5, and further The oil is returned to the oil reservoir 20 after flowing down, lubricating the planetary gears 13 such as gears and bearings where lubrication is required.

  The inverter unit 3 includes a power module 25 made of an IGBT element, a diode, and the like, and a capacitor 26, and is attached to the outside of a side surface 27 of the motor case 7 opposite to the axle 11. The power module 25 includes an IGBT element or the like that is mounted on the insulating layer 29 and serves as a switching element, and is attached so that the insulating layer 29 is directly attached to the side surface 27 of the motor case. The capacitor 26 is directly attached to the motor case side surface 27. As shown in FIG. 2, there are a plurality of power modules 25 connected to the U-phase, V-phase and W-phase of the stator coil 5a, and a plurality of capacitors 26. The inverter case 30 is made of synthetic resin or the like.

  The power module 25 is connected to a connection terminal 31 penetrating the side surface 27 at the lower part of the motor case 7, and the connection terminal 31 is insulated and sealed by a sealing material 32 made of synthetic resin, rubber or the like. It is led into the motor case 7 and connected to each phase coil of the stator. The capacitor 26 is connected to a connection terminal 33 penetrating the side surface 27 in the upper part of the motor case 7, and the connection terminal 33 is insulated and sealed by a sealing material 35 made of synthetic resin, rubber, etc. It is guided in the case 7. The inverter case 30 has a cover shape with one open, and is attached to the outside of the side surface 27 of the motor case 7 by a mounting portion 43 so as to cover the inverter unit 3 and the terminals 31 and 33. The inverter unit 3 is protected from dust and water.

  The inverter unit 3 is attached to the motor case 7 with the power module 25 facing down and the capacitor 26 facing up, and the power module 25 is an oil that is below the oil level 20a of the motor case 7. Arranged so as to correspond to the reservoir 20.

  Electric power is supplied to the inverter unit 3 from a power supply unit such as a battery mounted on the vehicle via a direct current generation circuit. Then, the inverter unit 3 is controlled to have a predetermined waveform based on the driver's required torque, vehicle speed, and the like, and is supplied to the stator 5 of the electric motor 2 to rotate the electric motor 2 at a predetermined rotational speed and torque. At this time, since the power module 25 is switched at a high speed, the power module 25 is likely to reach a high temperature. However, the power module 25 is in contact with the oil reservoir 20 in the motor case via the side surface 27 of the motor case 7. The module 25 is radiated and cooled by the oil. The power module 25 is preferably made of a SiC semiconductor with a low calorific value.

  FIG. 3 is a side view of the second case portion 7b of the motor case 7 as seen from the mating surface side. The second case portion 7b is integrally formed with seating surfaces 40, 40 'that contact the outer peripheral surface of the stator 5 and attach and fix the stator 5 to the second case portion 7b. The second case portion 7b is formed with the stator fixing seat surface 40 and a bearing hub 41 that rotatably supports the rotating shaft 16 integral with the drum member 15 on which the rotor 6 is mounted. 5 and the rotor 6 can be positioned with high accuracy, the gap between the stator 5 and the rotor 6 can be managed to a small amount, and the efficiency of the electric motor 2 can be improved.

  In general, as shown in FIG. 3A, the second case portion 7 b ′ is configured such that the stator fixing seat surface 40 ′ is formed in an annular shape over the entire circumference in accordance with the stator 5. Support. In the present embodiment, as shown in FIG. 3B, the stator fixing seat surface 40 has a lower portion D facing the mounting portion 42 of the lower connection terminal 31, that is, the oil reservoir 20 side is cut away. It has been released. As a result, heat generated by the electric motor 2, particularly the stator 5 having the coil 5 a, can be prevented from being transmitted to the power module 25 through the lower portion of the stator fixing seat surface 40 and the heat of the power module 25 can be prevented. The ratio of heat radiation to the oil in the oil reservoir 20 can be improved.

4 (A) and 4 (B) are side views of the second case part, which are partially changed, as seen from the mating surface side. 4A is a view in which a cooling fin (heat radiating plate) 45 is provided in the notched open portion [D portion of FIG. 2B] of the stator fixing seat surface 40. In FIG. In the second case portion 7b ₂ , a large number of cooling fins 45 extending in the vertical direction are formed between the annular rib 44 for attaching the resolver and the lower connection terminal mounting portion 42. The cooling fin 45 portion is generally located in the oil reservoir 20 below the oil level 20a, and the power module 25 is attached to the outside of the side surface 27 opposite to the cooling fin 45. .

Thus, the heat generated from the power module 25 is transmitted to the cooling fin 45 via the side surface 27 of the second case 7 part b ₂ of the motor case, and is efficiently radiated from the cooling fin to the oil in the oil reservoir 20. The

FIG. 4B shows a second case portion 7b ₃ that is further modified. In the second case portion 7b ₃ , a rectangular through hole 46 is formed in the side surface 27 of the notch opening portion of the stator fixing seat surface 40 (see D in FIG. 2B). Then, a plate (thermal conductive plate) 47 made of a material having high thermal conductivity such as copper is fitted into the through hole 46, and is embedded and hermetically sealed. The plate 47, since a separate part from the casing part 7b _3, fine processing is possible, the heat radiating portion of the inner the surface from such example multiple pin-shaped motor case 7 processing (cooling fins) 47a It becomes possible to do.

As shown in FIG. 5, the outside of the plate 47 is a flat surface, and is attached so that the power module 25 sticks to the flat surface. Low thermal conductivity sealing member 49 such as synthetic resin or rubber over the entire periphery of the plate 47 is attached, so that the seal member 49 is interposed between the through-hole 46 of the second case portion 7b ₃ The plate 47 is fitted into the through hole 46.

Therefore, according to the second case portion 7 b ₃ , the heat generated from the power module 25 is transmitted to the heat radiating portion 47 a via the plate 47 and is radiated to the oil in the oil reservoir 20 inside the motor case 7. At this time, the plate 47 is radiated with high efficiency in combination with the material having high thermal conductivity and the shape of the heat radiating portion 47a having a large surface area, and the power module 25 is efficiently cooled. Also, heat from the stator 5 etc. is transmitted to the side surface 27 of the second case portion 7b ₃ (46,42), is blocked by the low thermal conductivity of the sealing member 49, and is easily transmitted to the plate 47 .

  In addition, although the said in-wheel motor unit 1 demonstrated one wheel W, it is applied similarly to 2 wheels or 4 wheels.

1 Vehicle propulsion device (motor unit)
2 Electric Motor 3 Inverter Unit 5 Stator 6 Rotor 7 Motor Case 11 Axle 13 Planetary Gear 20 Oil Pool 25 Power Module 26 Capacitor 27 Side 40 Stator Fixing Seat 45 Cooling Fin 46 Through Hole 47 Heat Conducting Plate (Plate)
47a Heat radiation part 49 Seal member W Wheel

Claims (8)

An electric motor having a rotor housed in a motor case disposed in a wheel and interlocking with an axle and a stator fixed to the motor case;
In a vehicle propulsion device comprising: an inverter unit electrically connected to the electric motor and having a power module including a capacitor and a switching element;
Oil that lubricates and cools the electric motor is stored in the motor case in an oil-tight manner,
The inverter unit is attached to the side surface of the motor case opposite to the axle so that the power module is in a position corresponding to an oil reservoir in the motor case.
A vehicle propulsion device characterized by that. Between the rotor and the axle, there is a planetary gear that decelerates the rotation of the rotor and transmits it to the axle,
The planetary gear is arranged on the inner diameter side of the rotor so as to overlap at least partly in the axial direction when viewed from the radial direction with the rotor and the stator, and is lubricated with oil in the motor case.
The vehicle propulsion device according to claim 1. A stator fixing seating surface for supporting the stator is integrally formed on the inner side of the motor case,
The stator fixing seating surface is formed by cutting out the oil reservoir side and opening it.
The vehicle propulsion device according to claim 1 or 2. A cooling fin is integrally formed at a position corresponding to the power module inside the side surface of the motor case.
The vehicle propulsion device according to any one of claims 1 to 3. The power module is attached so as to stick directly to the outside of the side surface of the motor case.
The vehicle propulsion device according to any one of claims 1 to 4. A through hole is formed in a portion corresponding to the power module on the side surface of the motor case,
A heat conduction plate made of a material having high heat conductivity is fixed so as to close the through hole, and the power module is attached to the heat conduction plate.
The vehicle propulsion device according to any one of claims 1 to 3. A heat radiating part is integrally provided inside the motor case of the heat conducting plate,
The vehicle propulsion device according to claim 6. A seal member made of a material having low thermal conductivity is interposed between the through hole and the heat conductive plate.
The vehicle propulsion device according to claim 6 or 7.

Images