JP2007124798A - Motor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently dissipate heat in a sealed space having a heat generation source. <P>SOLUTION: Since this motor unit has a constitution such that heat in an internal space of a case 12 of an EPS motor 10 in a state of almost being sealed is efficiently dissipated via a penetration hole 32 of a motor flange 18, even when heat is generated, for example, in the particular state of the EPS motor 10 (large current generated by steering switching), the internal space of the case 12 can be prevented from being brought into an overheated state, and thereby a failure or the like caused by the heat generation can largely be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor unit that includes a motor that is a drive source and a speed change mechanism that changes the driving force of the motor.

  Conventionally, an electric power steering unit has been applied as an assist in operating a steering in a vehicle. A motor (hereinafter referred to as “EPS motor”) that is a drive source of the electric power steering unit has a flange portion and a yoke portion joined to each other, and maintains an airtight state as an external appearance (Patent Document 1, Patent Document 2).

In the structure of the EPS motor, there is a structure in which a through hole is provided on a mounting surface of a gear box (transmission) connected to a drive shaft of the EPS motor as a vent hole. The diameter of the through hole is about 2 mm. This through hole releases the heat in the substantially sealed yoke portion and enhances the heat dissipation effect.
JP 2004-040853 A JP 2003-235197 A

  However, with the recent increase in size of electric power steering units, the output of electric power steering units has been increasing so that they can be adapted to large vehicles. For this reason, when the maximum current flows through the EPS motor, such as when the steering is turned off, the yoke part generates heat, the ambient temperature in the almost sealed space loses its escape, and the function of the EPS motor itself may deteriorate. .

  In order to prevent this, overcurrent protection is performed by limiting the supply current on the controller (ECU) side that controls the electric power steering unit. This overheat protection function is for avoiding the worst state such as damage to the EPS motor (coil disconnection, substrate component damage, etc.), and sacrifices (decreases) the original purpose of electric assist.

  The present invention has been made in view of the above prior art, and an object thereof is to efficiently release heat in a sealed space having a heat source.

  The present invention relates to a motor having a driving force generation unit in a container forming a sealed space, and a speed change for receiving the driving force generated by the driving force generation unit via a driving shaft and shifting the driving force. And a mechanical unit, wherein the container is formed with a through-hole penetrating the inside and the outside of the container.

  With the increase in output due to the increase in size of the vehicle, the heat dissipation effect can be enhanced by providing a through hole serving as a ventilation port in the container of the motor. Thus, overheating can be prevented even with a large current such as steering steering.

The present invention also includes a motor provided with a driving force generator in a container that forms a sealed space, and the driving force generated by the driving force generator via a drive shaft, and the driving force is changed. A motor unit configured with a speed change mechanism unit,
An annular connecting portion that surrounds the periphery of the drive shaft that protrudes from the container of the motor is formed in a gear housing that serves as a container for housing the speed change mechanism, and the distal end side of the connecting portion is connected to the container, and the connection A through-hole is formed in the portion so as to penetrate the space portion surrounded by the connecting portion and the outside of the connecting portion, and the portion of the container facing the connecting portion is surrounded by the inside of the container and the connecting portion. It is characterized by forming a through-hole penetrating through the inside of the space.

  Along with the increase in output due to the increase in size of vehicles, the heat dissipation effect is enhanced by providing a through-hole that serves as a ventilation port for exhausting heat inside the motor to the outside of the motor at the connecting part of the motor housing and gear housing. Can do. Thus, overheating can be prevented even with a large current such as steering steering.

  Further, by forming a through hole in the gear housing that penetrates the inside and the outside of the gear housing, the heat dissipation effect can be further enhanced. Furthermore, it is possible to prevent dust and the like from entering the motor by mounting or inserting a filter member that is waterproof and breathable and that adsorbs dust in each through hole.

  As described above, the present invention has an excellent effect that heat in a sealed space having a heat source can be efficiently released.

  FIG. 1 shows a motor unit including an electric power steering motor (EPS motor) 10 according to the present embodiment and a gear box 50 as a transmission mechanism for shifting a driving force generated by the EPS motor 10. Has been.

  As shown in FIG. 2, the EPS motor 10 has its main components housed in a cylindrical case 12, and the internal space is almost sealed.

  A rotor shaft 14 to be described later protrudes from the end surface of the case 12 (the right end surface in FIG. 2).

  Further, a front bracket 16 having a substantially L-shaped cross section is provided on the right end side of the case 12 in FIG. 2. In this embodiment, the front bracket 16 is provided with a disk-shaped motor flange. The part 18 is attached by a bolt 19. For this reason, the EPS motor 10 has a case 12 and a motor flange portion 18 that are integrated with each other, and the opening side of the case 12 is closed by the motor flange portion 18 to form a sealed space in the container.

  The motor flange portion 18 has a role for connection with the gear box 50 that is a speed change mechanism portion, and is connected to an annular connection portion 54 formed in a gear housing 52 serving as a container for housing the speed change mechanism portion. Has been.

  The rotor shaft 14 is supported by bearings 20 provided at the left and right ends of the case 12 in FIG. 2, and is fitted in the rotor core 23 of the rotor 22 inside the case 12. A permanent magnet 25 is disposed on the outer peripheral surface of the rotor core 23.

  A stator 24 is attached to the inner peripheral surface of the case 12, and this stator 24 faces the permanent magnet 25 with a certain gap. A stator coil 24 </ b> A is wound around the stator 24.

  By causing a change in the magnetic field between the stator 24 and the rotor 22, the two rotate relative to each other (substantially, the rotor 22 rotates), and this rotational driving force is externally (via the rotor shaft 14). For example, it can be output to a gear box.

  Further, a resin mold body (not shown) is detachably disposed at the other inner end of the case 12 (the right end in FIG. 1). A substrate on which an electrical component for controlling the drive of the rotor 22 is mounted is mounted on the resin mold body. Electrical connection to the outside (electric power for energizing the stator coil 24A, etc.) is made through connection terminals provided on the substrate.

  Here, the motor flange portion 18 has a structure in direct contact with the case 12, and has an arrangement structure that easily receives heat in the inner space of the case 12.

  Therefore, heat generated in the case 12 is released to the outside through the motor flange portion 18 while maintaining a substantially sealed structure of the case 12.

  Specifically, as shown in FIGS. 2 and 3, in the present embodiment, a through hole 32 penetrating the inside and the outside of the container is formed in a portion of the motor flange portion 18 adjacent to the front bracket 16. In this through hole 32, a filter member 34 having predetermined waterproofness and air permeability, adsorbing dust and the like entering the through hole 32 of the container, and preventing the passage of dust was mounted.

  By forming the through-hole 32 in the motor flange portion 18, when the motor flange portion 18 receives heat from the inner space of the case 12, the through-hole 32 serves as a ventilation hole to dissipate heat, thereby eliminating heat accumulation. Can do. At this time, since the filter member 34 is mounted in the through hole 32, dust or the like does not enter the case 12, and the dust resistance can be maintained.

  The operation of this embodiment will be described below.

  In the EPS motor 10, not only normal operation but also a large current flows when the steering is stationary, and the stator coil 24A of the stator 24 generates heat. On the other hand, the inner space of the case 12 in which the stator 24 is housed is almost hermetically sealed due to dust resistance, and there is little escape space for heat.

  Therefore, it is necessary to indirectly release heat through the case 12 and the motor flange portion 18. In order to improve the efficiency of heat release (heat dissipation), a through hole 32 is formed in the motor flange portion 18 and the through hole 32 is used as a ventilation port. In addition, a filter member 34 is mounted in the through hole 32 in order to maintain dust resistance.

  As the filter member 34, GORE-TEX (registered trademark) is applicable. This Gore-Tex is continuous porous, the raw material compound is polytetrafluoroethylene (PTTE), and the PTTE fine powder is pressed and stretched in a uniaxial or biaxial direction at high temperature and high speed. Has been generated. When generating raw material compounds, the thickness, width, length, hole diameter, porosity, etc., can be set to create a wide variety of shapes and to be securely attached to the through hole 32. Can do.

  Among the many properties of this Gore-Tex, by utilizing gas permeability, that is, because the pores forming the porous structure are continuous, gas is permeated well, so that waterproofness is maintained along with air permeability. There is no problem that the motor flange 18 is rusted due to moisture absorption by moisture.

  When forming the through hole 32 as a ventilation port in the motor flange portion 18, as shown in FIG. 4, an elliptical through hole 32a is formed, and a filter member 34 is mounted in the through hole 32a. Alternatively, as shown in FIG. 5, it is possible to adopt a configuration in which a plurality of circular through holes 32b are formed and a filter member 34 is mounted in each through hole 32b.

  In the present embodiment, a through hole 32 penetrating the inside and the outside of the container is formed in a portion of the motor flange portion 18 adjacent to the front bracket 16, but as shown in FIG. A through hole 33 may be formed in a portion facing the gear box 50. In this case, as shown in FIG. 7, the gear housing 52 of the gear box 50 is formed so as to surround the rotor shaft (drive shaft) 14 protruding from the container of the ESP motor 10, and is connected to the flange portion 18. By forming a through hole 56 penetrating the inside of the space surrounded by the connecting portion 54 and the outside of the gear housing 52 in the annular connecting portion 54, and mounting the filter member 34 in each through hole 33, 56, The through holes 33 and 56 function as ventilation holes, and heat in the case 12 can be released to the outside of the gear housing 52 through the through holes 33 and 56 while maintaining dust resistance.

  When forming the through hole 56, an elliptical through hole 56a is formed as shown in FIG. 8, and the filter member 34 is mounted in the through hole 56a. Alternatively, as shown in FIG. It is possible to adopt a configuration in which a plurality of through holes 56b are formed and the filter member 34 is mounted in each through hole 56b.

  Further, by adopting a structure in which a through hole (not shown) penetrating the inside and the outside of the gear housing 52 is formed in the gear housing 52 and the filter member 34 is mounted in the through hole, heat dissipation is further achieved. The effect can be enhanced.

  As described above, in the present embodiment, the heat in the inner space of the case 12 of the EPS motor 10 that is substantially sealed is transferred to the through holes 32, 32a, 32b, 33 of the motor flange 18 or the through holes of the gear housing 52. The structure that efficiently discharges through 56, 56a, and 56b prevents the inner space of the case 12 from being overheated even when heat is generated in a specific state of the EPS motor 10 (a large current due to steering suspension). Therefore, failure due to heat generation can be greatly reduced.

  Moreover, since the filter member is attached to the through holes 32, 32a, 32b, 33, 56, 56a, 56b, it is possible to maintain the dustproof property while maintaining the air permeability and the waterproof property, and to prevent secondary contamination such as contamination. Can be prevented from occurring.

It is a front view of the motor unit which shows 1st Example of this invention. It is sectional drawing of the EPS motor in 1st Example of this invention. It is a principal part expanded sectional view of the EPS motor in 1st Example of this invention. It is a front view of the motor unit which shows 2nd Example of this invention. It is a front view of the motor unit which shows 3rd Example of this invention. It is a principal part expanded sectional view of the EPS motor which shows 4th Example of this invention. It is a front view of the motor unit which shows 4th Example of this invention. It is a front view of the motor unit which shows 5th Example of this invention. It is a front view of the motor unit which shows 6th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 EPS motor 12 Case 14 Rotor shaft 16 Front bracket 18 Flange 20 Bearing 22 Rotor 24 Stator 24A Stator coil 32, 32a, 32b, 33 Through hole 34 Filter member 50 Gear box 52 Gear housing 54 Connection part 56, 56a, 56b Through hole

Claims (4)

A motor including a driving force generation unit in a container forming a sealed space, a transmission mechanism unit that receives the driving force generated by the driving force generation unit via a driving shaft, and shifts the driving force; A motor unit comprising:
A motor unit, wherein the container is formed with a through-hole penetrating the inside and the outside of the container. A motor including a driving force generation unit in a container forming a sealed space, a transmission mechanism unit that receives the driving force generated by the driving force generation unit via a driving shaft, and shifts the driving force; A motor unit comprising:
A gear housing that houses the speed change mechanism portion is formed with an annular connecting portion that surrounds the periphery of the drive shaft that protrudes from the container of the motor, the distal end side of the connecting portion is connected to the container, Forming a through-hole penetrating the inside of the space surrounded by the connecting portion and the outside of the connecting portion, and in the space portion surrounded by the inside of the container and the connecting portion at a portion of the container facing the connecting portion A motor unit comprising a through hole penetrating through the motor unit. 3. The motor unit according to claim 1, wherein a through-hole penetrating the inside and the outside of the gear housing is formed in the gear housing that houses the speed change mechanism portion. 4. 4. The motor unit according to claim 1, wherein a filter member that is waterproof and breathable and that adsorbs dust is mounted in the through-hole. 5.

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