JP2015144532A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor which can be assembled with a position of a heat transfer component fixed while avoiding impairment of the ability of transferring heat generated from a heating component.SOLUTION: An electric motor M includes: a stator 1; a rotor 2 rotatably disposed at the inner peripheral side of the stator 1; bearings 41, 42 supporting a shaft 21 of the rotor 2; a steel plate bracket 5 which holds the bearings 41, 42 and houses and fixes the stator 1; and a circuit board 6 disposed in the steel plate bracket 5, the circuit board 6 on which a heating component 61 is mounted. The electric motor M further includes: a block shaped heat transfer component 8 which is disposed between the steel plate bracket 5 and the heating component 61 and transfers heat generated from the heating component 61 to the steel plate bracket 5; and a screw serving as a fixing member 10 which fixes the heat transfer component 8 to the steel plate bracket 5.

Description

  The present invention relates to an electric motor having a structure for radiating heat generated by a heat generating component.

  As a conventional electric motor, an inner rotor type electric motor is known in which a rotor is rotatably disposed inside a stator. The electric motor is used as, for example, a brushless DC motor for rotationally driving a blower fan mounted on an air conditioner.

  A conventional brushless DC motor includes a circuit board on which a heat module such as a power module and IGBT for driving the brushless DC motor is mounted in a steel plate bracket, and a block-shaped heat transfer component between the heat generating component and the steel plate bracket. Is arranged. Therefore, the heat generated by the heat generating component when the motor is driven is radiated to the steel plate bracket through the block-shaped heat transfer component. The conventional brushless DC motor configured as described above uses a heat-dissipating silicone adhesive having fluidity between the heat transfer component and the steel plate bracket in order to absorb manufacturing variations during assembly (for example, patents). Reference 1). However, in the conventional brushless DC motor, the heat transfer component is not completely fixed until the heat dissipation silicone adhesive is solidified. Therefore, the heat transfer component is heated until the heat dissipation silicone adhesive is cured during and after the assembly of the electric motor. It was necessary to strictly control the electric motor so that it would not move.

JP 2012-200055 A

  In view of the above problems, an object of the present invention is to provide an electric motor capable of assembling an electric motor in a state where the position of the heat transfer component is fixed without impairing the heat transfer performance of heat generated by the heat generating component.

  In order to solve the above problems, an electric motor of the present invention includes a stator, a rotor rotatably disposed on the inner peripheral side of the stator, a bearing that supports the shaft of the rotor, a bearing that holds the bearing, and accommodates the stator. It is equipped with a steel plate bracket to be fixed and a circuit board that is arranged in the steel plate bracket and on which the heat generating component is mounted, and is arranged between the steel plate bracket and the heat generating component and transfers heat generated by the heat generating component to the steel plate bracket. It is provided with the block-shaped heat-transfer component which heats, and the fixing member which fixes a heat-transfer component to a steel plate bracket.

  In the electric motor of the present invention, the heat transfer component has a screw hole, the fixing member is a screw, and the heat transfer component is fixed to the steel plate bracket by screwing the screw into the screw hole.

  According to the electric motor of the present invention, a block-shaped heat transfer component that is disposed between the steel plate bracket and the heat generating component and transfers heat generated by the heat generating component to the steel plate bracket, and fixing that fixes the heat transfer component to the steel plate bracket. By providing the member, the electric motor can be assembled with the position of the heat transfer component fixed without impairing the heat transfer performance of the heat generated by the heat generating component.

  According to the electric motor of the present invention, the heat transfer component has a screw hole, the fixing member is a screw, and the heat transfer component is fixed to the steel plate bracket by screwing the screw into the screw hole. While fixing the components securely to the steel plate bracket, the heat generated by the heat generating components can be radiated to the outside of the electric motor through the steel plate bracket and can be radiated to the outside of the electric motor through screws screwed into the screw holes. .

It is a side view including the partial cross section which shows the electric motor by this invention. It is the elements on larger scale which expanded the A section shown in FIG. 1 of the electric motor by this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 and 2 are diagrams for explaining an electric motor in the present embodiment. The electric motor M in this embodiment is an inner rotor type electric motor in which the rotor 2 is rotatably arranged on the inner peripheral side of the stator 1 that generates a rotating magnetic field. For example, the motor M is rotationally driven for a blower fan mounted on an air conditioner. Used as a brushless DC motor.

  As shown in FIGS. 1 and 2, the electric motor M is a double-shaft output type electric motor in which the shaft 21 protrudes outward from both sides in the axial direction of the steel plate bracket 5, and the stator core 11 whose outer periphery is covered with an insulator 12. The stator 1 provided, the rotor 2 centered on the shaft 21 and rotatably disposed on the inner peripheral side of the stator 1, the bearing 41 that supports one output side of the shaft 21, and the other shaft 21 A bearing 42 that supports the output side, a steel plate bracket 5 that holds and fixes the two bearings 41 and 42, and a power module or IGBT for forming the electric circuit and driving the motor M And a circuit board 6 on which a heat generating component 61 is mounted.

  The stator core 11 is formed in a cylindrical shape by laminating a plurality of thin steel plates, and includes an annular back yoke portion and a plurality of teeth portions extending from the back yoke portion to the inner diameter side (not shown). An insulator 12 is integrally formed on the stator core 11, and a stator winding 13 is wound around the tooth portion via the insulator 12. The insulator 12 is molded of resin and covers the stator core 11 except for the inner peripheral surface 111 (tip surface of the tooth portion) and the outer peripheral surface 112 (outer peripheral surface of the back yoke portion).

  The rotor 2 includes a shaft 21 disposed at the center, a rotor core 22 fixed to the shaft 21, and a permanent magnet 23 that covers the outer peripheral side of the rotor core 22. The rotor core 22 is formed in a cylindrical shape by laminating a plurality of thin steel plates, and a permanent magnet 23 is integrally fixed to the rotor core 22 with a resin. The stator 1 and the rotor 2 configured as described above are disposed on the steel plate bracket 5 so that the inner peripheral surface 111 of the stator core 11 faces the outer peripheral surface 231 of the permanent magnet 23 of the rotor 2 with a predetermined interval (so-called air gap). It is fixed.

  The steel plate bracket 5 includes two steel plate bracket pieces 51 and 52 divided in the axial direction of the shaft 21. A steel plate bracket piece 51 is provided on one output side of the shaft 21, and a steel plate bracket piece 52 is provided on the other output side of the shaft 21. One output-side steel plate bracket piece 51 is formed in a bottomed cylindrical shape and has a flange 511 at the open end. A part of the stator 1 is inserted into the steel plate bracket piece 51 along the axial direction of the shaft 21. At the center of the bottom surface 512 of the steel plate bracket piece 51, a bottomed cylindrical bearing house 513 having a smaller diameter than the bottom surface 512 and protruding in the axial direction is formed, and the bearing 41 is held by the bearing house 513.

  The other steel plate bracket piece 52 on the output side is formed in a bottomed cylindrical shape like the steel plate bracket piece 51 and has a flange 521 at the open end. The steel plate bracket piece 52 is arranged so as to cover the remaining portion of the stator 1 and the circuit board 6 arranged on one end side in the axial direction of the shaft 21 of the stator 1, and the flange 521 of the steel plate bracket piece 52 is the steel plate bracket piece 51. The flange 511 is fastened with a fastening member. A bottomed cylindrical bearing house 523 having a smaller diameter than the bottom surface 522 and protruding in the axial direction is formed at the center of the bottom surface 522 of the steel plate bracket piece 52, and the bearing 42 is held by the bearing house 523. An insertion hole 524 for inserting a fixing member 10 to be described later is formed on the bottom surface 522 of the steel plate bracket piece 52 on the outer peripheral side of the bearing house 523.

  The circuit board 6 has an electric circuit formed on the surface of the board, and a heat generating component 61 is placed on the electric circuit. The circuit board 6 is supported on one end side of the stator 1 and is disposed inside the steel plate bracket 5 together with the stator 1. The heat generating component 61 includes, for example, a power module, an IGBT, and the like, and controls energization to the stator winding 13. The heat generating component 61 is a component that generates heat when the stator winding 13 is energized. Heat generated by the heat generating component 61 is transferred to the steel plate bracket piece 52 via the first heat transfer member 7, the heat transfer component 8, and the second heat transfer member 9 which will be described later. As a result, the heat generated by the heat generating component 61 is radiated from the steel plate bracket piece 52 into the outside air. Between the steel plate bracket piece 52 and the heat generating component 61, the first heat transfer member 7, the heat transfer component 8, and the second heat transfer member 9 are formed from the surface of the heat generating component 61 facing the steel plate bracket piece 52. 52 are sequentially arranged.

  The first heat transfer member 7 is, for example, a heat-dissipating silicone adhesive having a heat transfer property that hardens after being applied to the surface of the heat-generating component 61. As for the heat-transfer component 8, metal materials, such as aluminum and copper, are formed in the block shape. The second heat transfer member 9 is, for example, a heat dissipation sheet having elasticity and heat transfer properties formed of a material such as silicone.

  The fixing member 10 is, for example, a screw to which a seal washer 101 is attached. The screw that is the fixing member 10 is used to fix the heat transfer component 8 and the heat dissipation sheet that is the second heat transfer member 9 to the steel plate bracket piece 52. The heat transfer component 8 has a screw hole 81 formed in the axial direction in which a screw that is the fixing member 10 is screwed, and the screw that is the fixing member 10 is inserted into the heat dissipation sheet that is the second heat transfer member 9. An insertion hole 91 is provided. The screws that are the fixing members 10 are inserted into the insertion holes 524 of the steel plate bracket pieces 52 and the heat dissipation sheet insertion holes 91 that are the second heat transfer members 9 from the outside of the steel plate bracket pieces 52, and the screw holes 81 of the heat transfer components 8. Are screwed together. For this reason, the heat radiating sheet which is the heat transfer component 8 and the second heat transfer member 9 is fixed to the steel plate bracket piece 52. The seal washer 101 prevents water from entering between the steel plate bracket piece 52 and the screw that is the fixing member 10, and prevents corrosion and insulation failure of the heat transfer component 8. Further, instead of the seal washer 101, an O-ring (not shown) may be attached to the screw.

  Next, the assembly procedure of the electric motor M will be described. First, after the stator 1 is press-fitted into the steel plate bracket piece 51, the bearing 41 attached to the shaft 21 of the rotor 2 is held in the bearing house 513. Thereafter, the circuit board 6 is placed on a terminal block (not shown) formed on one end side of the insulator 12 of the stator 1, and a terminal (not shown) connected to the stator winding 13 of the stator 1 and protruding outward from the terminal block. Are electrically connected to the electric circuit of the circuit board 6 by soldering. Next, the heat radiating sheet as the second heat transfer member 9 and the heat transfer component 8 are fixed to the steel plate bracket piece 52 using the screws as the fixing member 10. Thereafter, a heat radiating silicone adhesive is applied to the surface of the heat generating component 61 of the circuit board 6 as the first heat transfer member 7. Next, after the bearing 42 attached to the shaft 21 of the rotor 2 is held in the bearing house 523, the steel plate bracket piece 52 is fastened to the steel plate bracket piece 51 with a fastening member, whereby the assembly of the electric motor M is completed. When the heat transfer component 8 is fixed to the steel plate bracket piece 52 using the screws that are the fixing members 10, the heat dissipation sheet that is the second heat transfer member 9 is interposed between the heat transfer component 8 and the steel plate bracket piece 52. Therefore, heat transfer from the heat transfer component 8 to the steel plate bracket piece 52 is improved. And since the heat-transfer component 8 is being fixed to the steel plate bracket piece 52 at the time of fastening with the steel plate bracket piece 51 and the steel plate bracket piece 52, the heat transfer component 8 does not shift | deviate. Further, the positions of the insertion hole 524 formed in the steel plate bracket piece 52 and the circuit board 6 are fastened to the steel plate bracket piece 51 on which the circuit board 6 is arranged by fastening the steel plate bracket piece 52 to which the heat transfer component 8 is fixed through the insertion hole 524. When doing so, the heat transfer component 8 and the heat generating component 61 are in a positional relationship facing each other. As a result, the heat transfer component 8 and the second heat transfer member 9 are disposed between the heat generating component 61 and the steel plate bracket piece 52 on the heat dissipation silicone adhesive that is the first heat transfer member 7 along the axial direction of the shaft 21. The heat-dissipating sheets are stacked, and a heat transfer path for transferring the heat generated by the heat generating component 61 is well formed. In addition, the heat-dissipating silicone adhesive or elasticity having fluidity until the heat generated by the heat-generating component 61 between the heat-generating component 61 and the heat-transfer component 8 is cured as the first heat-transfer member 7 that transfers heat to the heat-transfer component 8. By providing the heat dissipating sheet, the heat transfer property between the heat generating component 61 and the heat transfer component 8 can be ensured even if there is an influence of the dimensional variation of individual components and the flatness of the contact surface.

  According to the electric motor M according to the embodiment described above, the steel plate bracket 5 that holds the bearings 41 and 42 and accommodates and fixes the stator 1, and the circuit board 6 that is disposed in the steel plate bracket 5 and on which the heat generating component 61 is mounted. The block-shaped heat transfer component 8 that is disposed between the steel plate bracket 5 and the heat generating component 61 and transfers heat generated by the heat generating component 61 to the steel plate bracket 5, and the heat transfer component 8 to the steel plate bracket 5. And a screw 10 as a fixing member to be fixed. As a result, the heat transfer component 8 is not displaced during assembly of the electric motor M, and the steel plate bracket 5 can be assembled. Moreover, even if the electric motor M is moved or laid down before the heat radiating silicone adhesive as the first heat transfer member 7 is solidified after the electric motor M is assembled, the heat transfer component 8 is not displaced. Therefore, the electric motor M can be assembled in a state where the position of the heat transfer component 8 is fixed without impairing the heat transfer property of the heat generated by the heat generating component 61.

  Further, according to the electric motor M according to the present embodiment, the heat transfer component 8 has the screw hole 81 and has a screw as the fixing member 10, and the screw is screwed into the screw hole 81 so that the heat transfer component 8 is a steel plate. Fix to the bracket 5. As a result, while securely fixing the heat transfer component 8 to the steel plate bracket 5, the heat generated by the heat generating component 61 is radiated to the outside of the electric motor M through the steel plate bracket 5 and the screw screwed into the screw hole 81 is removed. The heat can be radiated to the outside of the electric motor M.

  In the electric motor M according to the present embodiment described above, the heat transfer component 8 is formed with the screw hole 81 having a thread on the inner surface, but the present invention is not limited thereto, and the heat transfer component 8 has no screw thread. And a self-tapping screw may be used as the fixing member 10 instead of the screw. Further, the electric motor M according to the present embodiment is a double-shaft output type electric motor, but the present invention is not limited to this, and the single shaft in which the shaft 21 projects outward from only one of the steel plate bracket piece 51 or the steel plate bracket piece 52 is not limited thereto. An output type electric motor may be used. Moreover, in the electric motor M by this embodiment, although the heat radiating sheet was arrange | positioned as the 2nd heat transfer member 9 between the heat transfer components 8 and the steel plate bracket piece 52, this invention is not limited to this, The 2nd heat transfer member 9 may be replaced with a heat dissipation silicone adhesive instead of the heat dissipation sheet, and the second heat transfer member 9 may be omitted. Furthermore, in the electric motor M according to the present embodiment, the insulator 12 is integrally formed with the stator core 11, but the stator core 11 and the insulator 12 may be formed separately.

DESCRIPTION OF SYMBOLS 1 Stator 11 Stator core 111 Inner peripheral surface 112 Outer peripheral surface 12 Insulator 13 Stator winding 2 Rotor 21 Shaft 22 Rotor core 23 Permanent magnet 231 Outer peripheral surface 41 Bearing 42 Bearing 5 Steel plate bracket 51 Steel plate bracket piece 511 Flange 512 Bottom 513 Bearing house 52 Steel plate bracket Piece 521 Flange 522 Bottom surface 523 Bearing house 524 Insertion hole 6 Circuit board 61 Heating component 7 First heat transfer member (heat dissipation silicone adhesive)
8 Heat transfer component 81 Screw hole 9 Second heat transfer member (heat dissipation sheet)
91 Insertion hole 10 Fixing member (screw)
101 Seal washer M Electric motor

Claims (2)

A stator, a rotor rotatably disposed on an inner peripheral side of the stator, a bearing that supports a shaft of the rotor, a steel plate bracket that holds the bearing and accommodates and fixes the stator, and the steel plate bracket An electric motor comprising a circuit board disposed within and mounted with a heat generating component,
A block-shaped heat transfer component that is disposed between the steel plate bracket and the heat generating component and transfers heat generated by the heat generating component to the steel plate bracket; and a fixing member that fixes the heat transfer component to the steel plate bracket; An electric motor comprising:   The heat transfer component has a screw hole, the fixing member is a screw, and the screw is screwed into the screw hole to fix the heat transfer component to the steel plate bracket. The electric motor described.

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