JP2009254149A - Vehicle motor with speed-reduction mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cool a rotor by a simple structure while maintaining size-reduction of a motor body in a vehicle motor with a speed-reduction mechanism that has the motor body and a speed-reduction mechanism for transmitting rotation of a rotary shaft of the motor body to an output shaft while decelerating the rotation. <P>SOLUTION: A rotary-shaft gear 42 is provided on a rotary shaft 20 while a speed-reduction gear 50 engages with the rotary-shaft gear 42. In the speed-reduction gear 50, its side face 50a facing a rotor 26 includes fins 60. By this configuration, the fins 60 are also rotated by the rotation of the speed-reduction gear 50 so as to feed air from the speed-reduction gear 50 toward the rotor 26, thereby cooling the rotor 26. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor with a deceleration mechanism for a vehicle, and more particularly to a structure for cooling a rotor.

  A motor body including a rotor fixed to the rotating shaft and having a permanent magnet, and a stator disposed around the rotor, and a speed reducing mechanism connected to the rotating shaft and decelerating the rotation of the rotating shaft and transmitting it to the output shaft There is known a motor with a speed reduction mechanism having the following.

  Conventionally, a motor with a speed reduction mechanism is used for the purpose of driving a driven object by generating a large output with small power. For example, a motor with a speed reduction mechanism is installed in a limited installation space of a vehicle, and is employed as a prime mover that requires a large output to drive the vehicle.

  Patent Document 1 listed below describes a motor in which a fan is provided on a rotating shaft of the motor. According to this motor, when the fan rotates with the rotation of the rotating shaft, air flows between the stator and the rotor, and the stator and the rotor can be cooled.

JP-A-5-103443

  In the motor body provided in the motor with a speed reduction mechanism used as a motor for the vehicle as described above, high rotation speed can be achieved in order to obtain high output, and miniaturization is achieved due to a demand for space saving. As a result, while the internal heat generation increases due to the high rotation speed, the heat dissipation area becomes small due to the miniaturization, and the motor body cannot be sufficiently cooled. In particular, in a motor having a permanent magnet in the rotor, there is a problem that when the rotor is heated to a high temperature without being cooled, the permanent magnet is demagnetized and the performance of the motor is deteriorated.

  With respect to this problem, in the motor of Patent Document 1, the stator and the rotor can be cooled by the air sent by the fan. However, in order to provide the fan, it is necessary to lengthen the rotating shaft, and there is a problem that the motor body becomes large correspondingly.

  An object of the present invention is to provide a motor with a deceleration mechanism for a vehicle that can cool a rotor with a simple structure while maintaining a reduction in size of a motor body.

  The present invention includes a motor main body including a rotor fixed to a rotating shaft and having a permanent magnet, a stator disposed around the rotor, and a speed reducing mechanism that decelerates the rotation of the rotating shaft and transmits it to the output shaft. A motor with a reduction mechanism for a vehicle having a rotation shaft gear provided on a rotation shaft and connected to the reduction mechanism, and a reduction gear that forms part of the reduction mechanism and meshes with the rotation shaft gear, the rotation shaft gear And a fin provided on a side surface of the speed reduction gear that faces the rotor, and the fin causes air toward the rotor by rotation of the speed reduction gear. It is characterized by sending and cooling a rotor.

  The motor body further includes a terminal block to which an electric wire is connected, and the fin can send air to the terminal block by the rotation of the reduction gear.

  According to the motor with a speed reduction mechanism for a vehicle of the present invention, the rotor can be cooled with a simple structure while maintaining the miniaturization of the motor body.

  Embodiments of a motor with a deceleration mechanism for a vehicle according to the present invention will be described below with reference to the drawings. As an example, an electric vehicle driven by electricity will be described, and a motor with a vehicle speed reduction mechanism mounted on the electric vehicle will be described. The present invention is not limited to a motor with a vehicle speed reducer for an electric vehicle, but can also be applied to a motor with a vehicle speed reducing mechanism used in a hybrid vehicle that travels with the output of an engine and a motor.

  FIG. 1 is a diagram illustrating a schematic configuration of an electric vehicle according to the present embodiment. The electric vehicle 10 includes a motor with a vehicle speed reduction mechanism (hereinafter simply referred to as a motor) 12 as a prime mover. The motor 12 is connected to the left and right drive wheels 18 via the output shaft 14 and the differential mechanism 16. The power of the motor 12 is distributed and transmitted to the left and right drive wheels 18 by the differential mechanism 16, and the electric vehicle 10 travels.

  The motor 12 includes a rotation shaft 20 and includes a motor body 22 and a speed reduction mechanism 24 that decelerates the rotation of the rotation shaft 20 and transmits it to the output shaft 14.

  The motor body 22 will be described with reference to FIGS. 1 and 2. FIG. 2 is a cross-sectional view showing a schematic configuration of the motor 12 according to the present embodiment. The motor body 22 includes a rotor 26 fixed to the rotating shaft 20 and a stator 28 fixed to the case 34 of the motor 12 so as to surround the rotor 26.

  The rotor 26 is a cylindrical magnetic body that is concentric with the rotary shaft 20 and is configured by, for example, stacking steel plates in the axial direction. A plurality of permanent magnets 32 are arranged in the circumferential direction on the rotor 26. The permanent magnet 32 may be disposed on the outer periphery of the rotor 26, or may be formed in the rotor 26 with a hole extending in the axial direction and embedded in the hole.

  The rotating shaft 20 is rotatably supported by a first bearing 36 included in the case 34. The rotating shaft 20 is a hollow shaft in which a hole extending in the axial direction is formed, and the output shaft 14 passes through the hole. The output shaft 14 is rotatably supported by a second bearing 38 included in the case 34. The output shaft 14 and the rotating shaft 20 are relatively rotatable. The rotary shaft 20 is provided with a rotary shaft gear 42, and the output shaft 14 is provided with an output shaft gear 44. The rotation shaft gear 42 and the output shaft gear 44 are connected via a speed reduction mechanism 24 described later.

  The stator 28 is disposed around the rotor 26 with a slight gap. The stator 28 has magnetic poles (not shown) that protrude to the inner peripheral side of the stator 28 and are arranged at a predetermined interval in the circumferential direction. In a slot (not shown) that is a space between the magnetic poles, an exciting coil 30 formed by winding a conductive wire around the magnetic poles is disposed. When the excitation coil 30 is energized, a rotating magnetic field is generated in the stator 28, and a force attracted by the rotating magnetic field is generated in the rotor 26 having the permanent magnet 32, so that the rotor 26 rotates.

  The motor body 22 has a terminal block 40 to which an electric wire from a power source is connected. The terminal block 40 in the present embodiment is on the outer side in the radial direction from the stator 28 and is fixed to the inner side of the case 34. The terminal block 40 is electrically connected to the excitation coil 30 and energizes the excitation coil 30 with power from a power source.

  Next, the speed reduction mechanism 24 will be described with reference to FIG. The speed reduction mechanism 24 has an intermediate shaft 46 that transmits power from the rotary shaft 20 to the output shaft 14. The intermediate shaft 46 is rotatably supported by a third bearing 48 included in the case 34. The intermediate shaft 46 is provided with a reduction gear 50 that meshes with the rotary shaft gear 42 and an intermediate gear 52 that meshes with the output shaft gear 44. The reduction gear 50 is formed with a diameter larger than the diameter of the rotary shaft gear 42. Therefore, in the reduction gear 50 from the rotary shaft gear 42, the rotational speed is reduced and power is transmitted. On the other hand, the intermediate gear 52 is formed with a diameter smaller than the diameter of the output shaft gear 44. Therefore, in the output shaft gear 44 from the intermediate gear 52, the rotational speed is reduced and power is transmitted. With this configuration, the speed reduction mechanism 24 can reduce the rotation of the rotary shaft 20 and transmit it to the output shaft 14.

  The case 34 in the present embodiment has a wall 58 that separates the motor body 22 and the speed reduction mechanism 24. An opening 58 a is formed in the wall 58. As shown in FIG. 2, two openings 58 a are provided between the reduction gear 50 and the motor body 22. One opening 58 a is provided between the reduction gear 50 and the rotor 26, and the other opening 58 a is provided between the reduction gear 50 and the terminal block 40. The number of openings 58a is an example, and is not limited to this number.

  The reduction gear 50 according to the present invention is provided with fins 60 on the side surface 50 a facing the rotor 26. The fins 60 are thin plate-like, and a plurality of fins 60 are provided in the circumferential direction of the side surface 50a so as to protrude in the axial direction from the side surface 50a. In addition, if the fin 60 can send air toward an axial direction by rotation of the reduction gear 50, a shape will not be limited and a number will not be limited either.

  The operation of the motor 12 according to this embodiment will be described. As described above, the energization of the exciting coil 30 causes the rotor 26 to rotate. The rotary shaft 20 rotates in synchronization with the rotation of the rotor 26, and this rotation is decelerated by the speed reduction mechanism 24 and transmitted to the output shaft 14. At this time, the fin 60 is rotated by the rotation of the reduction gear 50 that constitutes a part of the reduction mechanism 24. By the rotation of the fin 60, air is sent from the reduction gear 50 toward the motor body 22 side. More specifically, since the opening 58a is provided in the wall 58 between the fin 60 and the motor main body 22, the air flow generated by the rotation of the fin 60 passes through the opening 58a to the motor main body 22. Directed. The motor body 22 is also directed to the rotor 26 and the terminal block 40, particularly as shown by the arrows in FIG.

  According to the motor 12 according to the present embodiment, even if the rotor 26 rotates at a high speed and generates heat, the rotation of the fins 60 can send air to the rotor 26 to cool the rotor 26. As a result, demagnetization of the permanent magnet 32 due to the high temperature of the rotor 26 can be prevented. Further, air is sent to the terminal block 40 by the rotation of the fins 60. Thereby, since the deposit | attachment adhering to the terminal block 40 can be removed with a wind pressure, the short circuit between the phases of the terminal part of the terminal block 40 and a ground fault can be prevented beforehand.

  In the present embodiment, the case where the reduction gear 50 is formed with a diameter larger than the diameter of the rotation shaft gear 42 has been described, but the diameters of the reduction gear 50 and the rotation shaft gear 42 may be the same. Also in this case, since the intermediate gear 52 is formed with a diameter smaller than the diameter of the output shaft gear 44, the rotational speed is reduced from the intermediate gear 52 to the output shaft gear 44, so that power is transmitted. Can serve as

It is a figure showing the schematic structure of the electric vehicle concerning this embodiment. It is sectional drawing which shows schematic structure of the motor with a deceleration mechanism which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 Motor with deceleration mechanism for vehicles, 14 Output shaft, 20 Rotating shaft, 22 Motor main body, 24 Reduction mechanism, 26 Rotor, 28 Stator, 32 Permanent magnet, 42 Rotating shaft gear, 50 Reduction gear, 50a Side, 60 Fin

Claims (2)

A motor main body including a rotor fixed to the rotating shaft and having a permanent magnet, and a stator disposed around the rotor;
A deceleration mechanism that decelerates the rotation of the rotation shaft and transmits it to the output shaft;
In a motor with a deceleration mechanism for a vehicle having
A rotary shaft gear provided on the rotary shaft and connected to the speed reduction mechanism;
A reduction gear that constitutes a part of a reduction mechanism and meshes with the rotation shaft gear, and is formed with a diameter larger than or equal to the diameter of the rotation shaft gear;
A fin provided on a side surface of the reduction gear facing the rotor;
Have
The fins send air toward the rotor by rotation of the reduction gear to cool the rotor.
A motor with a deceleration mechanism for a vehicle. The motor with a deceleration mechanism for a vehicle according to claim 1,
The motor body further has a terminal block to which the electric wire is connected,
The motor with a speed reduction mechanism for a vehicle, wherein the fin sends air to the terminal block by the rotation of the speed reduction gear.

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