JP2014093854A - Motor unit for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor unit for a vehicle which inhibits heat of a heating component attached to a circuit board from being transmitted to the other component and also inhibits the increase of the number of components forming a circuit device and the increase of a space on which the circuit device is mounted.SOLUTION: A motor unit 10 for a vehicle includes: a motor 12; a circuit board 18 to which a circuit element 16 for controlling rotations of the motor 12 is attached; and a heat sink 20 for radiating heat of the circuit element 16. The heat sink 20 contacts the circuit board 18 at a portion facing circuit elements (FETs 41A to 41F and a reverse connection prevention FET 41G) which generate a large amount of heat during the operation and is separated from the circuit board 18 at a portion facing circuit elements (capacitors 40A, 40B, 40C, 40D) which generate a small amount of heat.

Description

  The present invention relates to a vehicle motor unit.

  Patent Document 1 below discloses a configuration in which a circuit board constituting a control device that controls a motor unit or the like is attached to a metal case directly or via a molded resin. With such a configuration, it is possible to radiate the heat of the high heat generation component (high heat generation circuit element) attached to the circuit board to the metal case side.

JP 2006-108398 A Japanese Patent Laid-Open No. 9-84319 JP 2000-318628 A

  However, in the configuration described in Patent Document 1, since the entire circuit board is in contact with the metal case directly or via resin, the heat of the high heat-generating component is attached to the circuit board via the metal case. It is conceivable that the signal is transmitted to the component (circuit element). When the other component is a component that does not want to receive heat, it is desired to suppress the heat of the high heat generation component from being transmitted to the other component.

  In order to suppress the heat of the high heat generation component from being transmitted to other components, in the configuration described in Patent Document 2, the high heat generation component is arranged apart from the circuit board. Heat is dissipated through the heat sink. Moreover, in the structure described in the said patent document 3, the circuit board in which a high heat-emitting component is attached and the circuit element in which another component is attached are divided. However, in such a configuration, the number of parts constituting the circuit device and the space for mounting the circuit device are increased.

  In consideration of the above facts, the present invention can suppress the heat of the heat-generating component attached to the circuit board from being transmitted to other components, and can increase the number of components constituting the circuit device and the circuit device. It is an object to obtain a vehicle motor unit capable of suppressing an increase in space for mounting.

  According to a first aspect of the present invention, a motor unit for a vehicle according to the present invention is provided with a motor that rotates an output shaft around its axis when energized, and a heat generating component and a control component for controlling the rotation of the output shaft. A circuit board and a portion of the circuit board opposite to the mounting surface of the heat generating component and the control component, and a portion facing the heat generating component is in contact with the circuit board and facing the control component. The part includes a heat dissipating member spaced from the circuit board.

  In the first aspect of the present invention, the rotation of the output shaft of the motor is controlled by the heat generating component and the control component attached to the circuit board. Moreover, in this invention, the heat radiating member for radiating the heat | fever of a heat generating member is arrange | positioned on the opposite side to the attachment surface of the heat-emitting component and control component in a circuit board. Further, the heat dissipating member and the circuit board are in contact with each other at a portion facing the heat generating component and are separated at a portion facing the control component. Thereby, it is suppressed that the heat of a heat-emitting component is transmitted to a control component via a heat radiating member.

  Further, in the present invention, in order to prevent the heat of the heat generating component from being transmitted to the control component, it is not necessary to take measures such as separating the circuit board to which the heat generating component is attached from the circuit board to which the control component is attached. As a result, according to the present invention, it is possible to suppress an increase in the number of parts constituting the circuit device and an increase in the space for mounting the circuit device.

  A vehicle motor unit according to a second aspect of the present invention is the vehicle motor unit according to the first aspect, wherein the circuit board is configured integrally with the motor, and the circuit board is accommodated in a case. An exposed portion that is exposed to the outside of the case is provided in a portion of the heat dissipation member that faces the control component.

  In this invention of Claim 2, the exposed part of the heat radiating member is exposed from the case which accommodates a circuit board. Therefore, the heat of the heat generating component is radiated from the exposed portion of the heat radiating member toward the outside of the case through the heat radiating member. As a result, an increase in temperature in the vicinity of the exposed portion of the heat radiating member is suppressed, and as a result, the amount of heat transmitted from the portion to the control component (the amount of heat transmitted by convection and radiation) is reduced. That is, in this invention, it can suppress further that the heat | fever of a heat-emitting component is transmitted to a control component via a thermal radiation member.

It is a disassembled perspective view which decomposes | disassembles and shows the motor unit for vehicles of this embodiment. It is sectional drawing which shows the cross section which cut | disconnected the motor unit for vehicles of this embodiment along the axial direction of the motor. (A) It is a perspective view which shows the circuit board to which the heat sink and the circuit element were attached, (B) is a side view of the circuit board shown to (A), (C) is from the opposite direction to (A). It is a perspective view which shows the circuit board which looked. It is the top view which looked at the circuit board from the opposite direction to the surface where the heat sink was attached. (A) is the top view which looked at the heat sink from the circuit board side, (B) is the expansion perspective view which expands and shows the edge part of the circuit board shown by (A).

  Next, a vehicle motor unit according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the vehicle motor unit 10 according to the present embodiment is a so-called blower motor unit used for blowing air from an in-vehicle air conditioner as an example. Specifically, the vehicle motor unit 10 dissipates heat from the motor 12 that rotates the output shaft about its axis, the circuit element 16 that controls the rotation of the motor 12, the circuit board 18, and the circuit element 16. A motor drive control device 34 including a heat sink 20 as a heat radiating member. That is, the vehicle motor unit 10 is configured integrally with a motor 12 and a motor drive control device 34 that controls the rotation of the motor 12. Hereinafter, the motor 12 will be described first, then the circuit board 18 and the circuit element 16 constituting the motor drive control device 34 will be described, and finally the heat sink 20 will be described.

(Motor 12)
The motor 12 includes an output shaft 14, a rotor 22, and a stator 24 as main elements.

  The output shaft 14 is configured by subjecting a columnar steel material to surface treatment such as carburization, and is rotatably supported by a bearing member 15.

  The rotor 22 is formed in a bottomed cylindrical shape with one end open, a disc-shaped bottom wall 22A, and a peripheral wall 22B extending from the outer peripheral end of the bottom wall 22A to the one end side of the rotor 22, It has. Further, an insertion hole 22C into which the output shaft 14 is inserted is provided at the center of the bottom wall 22A, and the rotor 22 and the output shaft 14 are integrated by pressing the output shaft 14 into the insertion hole 22C. It can be rotated. A rotor magnet 23 is provided inside the peripheral wall 22B.

  The stator 24 is configured by winding a conductive winding 26 around a stator core 28 formed in an annular shape. Further, the stator 24 is disposed on the radially inner side of the peripheral wall 22B of the rotor 22, and the rotor 22 can rotate together with the output shaft 14 by receiving a magnetic field generated by the stator 24. More specifically, the stator 24 is an electromagnet in which a winding 26 is wound around a core member 30 that constitutes a stator core 28, and constitutes three phases of U phase, V phase, and W phase. Each of the U-phase, V-phase, and W-phase of the stator 24 generates a so-called rotating magnetic field by switching the polarity of the magnetic field generated by the electromagnet under the control of a motor drive control device 34 described later. The stator 24 is attached to a motor drive control device 34 via an upper case 32 as a case.

(Circuit board 18 and circuit element 16)
The circuit board 18 is formed in a rectangular plate shape, and constitutes a motor drive control device 34 (circuit device) together with the circuit element 16 and the heat sink 20 described in detail later. Specifically, as shown in FIG. 4, power supply terminals 36 </ b> A, 36 </ b> B, and 36 </ b> C for supplying power to the U phase, V phase, and W phase of the stator 14 are provided near the center of the circuit board 18. It has been. In addition, a connector 38 to which a control device such as an ECU (Electronic Control Unit) is connected via a harness and a connector (not shown) is attached to the circuit board 18. Furthermore, a plurality of circuit elements 16 are attached to the circuit board 18. More specifically, capacitors 40A, 40B, 40C, and 40D as control components are attached to the circuit board 18 in a state of being connected in parallel. Further, FETs 41A, 41B, 41C, 41D, 41E, and 41F as heat generating components are attached to the circuit board 18. The FETs 41A and 41D are configured to perform switching of the supplied power in the U phase, the FETs 41B and 41E in the V phase, and the FETs 41C and 41F in the W phase. Furthermore, a noise removing coil 44 is attached to the circuit board 18, and a reverse connection prevention FET 41 </ b> G (heat generating component) and a large-capacitance capacitor 42 for circuit protection are attached. Further, a microcomputer 46 for controlling the inverter circuit is attached to the circuit board 18.

  As shown in FIG. 2, the circuit board 18 is accommodated between the lower case 48 and the upper case 32 by attaching the lower case 48 as a case to the upper case 32.

(Heat sink 20)
In the circuit element 16 described above, the FETs 41A to 41F and the reverse connection prevention FET 41G generate significant heat during operation. Therefore, in this embodiment, as shown in FIGS. 3A to 3C, the heat sink 20 is attached with circuit elements (FETs 41 </ b> A to 41 </ b> F and reverse connection prevention FETs 41 </ b> G) that generate significant heat during operation on the circuit board 18. It is attached via a fixing bolt 50 to a portion (surface opposite to the surface on which the FETs 41A to 41F and the reverse connection prevention FET 41G are attached) facing the portion in the plate thickness direction. Specifically, the heat sink 20 is made of a metal such as aluminum having good thermal conductivity, and is formed in a substantially rectangular plate shape when viewed from the thickness direction of the circuit board 18. In addition, a plurality of protrusions 52 as exposed portions are provided at one end in the short direction of the heat sink 20 along the longitudinal direction of the heat sink 20. The protrusions 52 are separated from the circuit board 18. It is formed in the column shape which protrudes toward. By having the plurality of protrusions 52, the surface area of the heat sink 20 is increased, and the heat dissipation performance of the heat sink 20 is improved. In addition, as illustrated in FIG. 2, the protrusion 52 is exposed from the upper case 32 in a state where the circuit board 18 is accommodated between the lower case 48 and the upper case 32.

  In addition, as shown in FIGS. 3C, 5 </ b> A, and 5 </ b> B, a portion of the heat sink 20 that faces the circuit elements (FETs 41 </ b> A to 41 </ b> F and reverse connection prevention FET 41 </ b> G) is along the circuit board 18. An extending facing surface 54 is provided.

  Further, the heat sink 20 is provided with a first leg portion 56 and a second leg portion 58 that form a gap in which a heat dissipation material is interposed between the circuit board 18 and the facing surface 54 by contacting the circuit board 18. Yes.

  The first leg portions 56 are provided at both ends in the longitudinal direction of the heat sink 20 and are formed in a rectangular shape with the short direction of the heat sink 20 as the longitudinal direction. Further, the first leg portion 56 protrudes toward the circuit board 18 from the above-described facing surface 54. Furthermore, the end surface in the protruding direction of the first leg portion 56 is an abutting surface 56 </ b> A that abuts on the circuit board 18.

  The second leg portions 58 are disposed at both end portions in the longitudinal direction of the heat sink 20 and corner portions on the other end side in the short direction of the heat sink 20. Further, the second leg portion 58 protrudes toward the circuit board 18 from the above-described facing surface 54. Further, the end surface in the protruding direction of the second leg portion 58 is a contact surface 58A that contacts the circuit board 18, and the contact surface 58A and the contact surface 56A of the first leg portion 56 are substantially plane. It is set to be one.

  In addition, a recess 60 that is recessed in a direction away from the circuit board 18 is provided in a portion adjacent to the facing surface 54. The recess 60 includes a first recess 60A disposed between the first leg 56 and the facing surface 54, a second recess 60B disposed between the second leg 58 and the facing surface 54, and a heat sink. And a third recess 60 </ b> C disposed along the outer peripheral edge of the 20.

  A portion of the first leg portion 56 on the other end side of the heat sink 20 is a fastening portion 62, and a screw hole 62 </ b> A into which the fixing bolt 50 is screwed is formed in the fastening portion 62. . The pair of fastening portions 62 are arranged so as to sandwich the facing surface 54, and a line L connecting the pair of fastening portions 62 (screw holes 62 </ b> A) contacts the circuit board 18 and the facing surface 54. It arrange | positions in the intermediate part of (the part enclosed with the dashed-two dotted line in FIG. 4). In other words, a portion where the circuit board 18 and the facing surface 54 are in contact with each other by a line L connecting the pair of fastening portions 62 (screw holes 62A) (a portion surrounded by a two-dot chain line in FIG. 4) is a short of the heat sink 20. It is the structure divided | segmented into the substantially bisection in the hand direction. In the present embodiment, the direction in which the line L connecting the pair of fastening portions 62 extends coincides with the longitudinal direction of the heat sink 20.

  Further, the surface of the heat sink 20 that faces the circuit elements (capacitors 40A, 40B, 40C, and 40D), and the surface opposite to the direction in which the protruding portion 52 protrudes is inclined with respect to the direction in which the circuit board 18 extends. The inclined surface 64 extends. The inclined surface 64 is set so that the distance from the circuit board 18 gradually increases toward one end side in the short direction of the heat sink 20.

  The heat sink 20 is attached to the circuit board 18 via the fixing bolt 50 after the heat sink 20 (not shown) having a gel-like and thermal conductivity is applied to the facing surface 54 of the heat sink 20 described above. As a result, the facing surface 54 of the heat sink 20 and the circuit board 18 are in contact with each other through the heat dissipation material. As an example of the heat dissipation material, fluid silicone grease is used. However, a silicone resin heat dissipation material that is hardened by heat generated from an element such as a FET in the form of a fluid gel at room temperature can also be used. .

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  As shown in FIGS. 1 and 2, in the vehicle motor unit 10 of the present embodiment, the rotation of the output shaft 14 of the motor 12 is controlled by a circuit element 16 attached to a circuit board 18. In this embodiment, as shown in FIGS. 4 and 5, a heat dissipation material is interposed between the circuit elements (FETs 41 </ b> A to 41 </ b> F and the reverse connection prevention FET 41 </ b> G) and the facing surface 54 of the heat sink 20. Therefore, the heat of the circuit elements (FETs 41 </ b> A to 41 </ b> F and the reverse connection prevention FET 41 </ b> G) that generate heat by being energized is radiated through the heat dissipation material and the heat sink 20. Further, in the present embodiment, the heat sink 20 is attached to the circuit board 18 via a pair of fastening portions 62 arranged so as to sandwich the facing surface 54, and a line L connecting the pair of fastening portions 62 is The circuit board 18 and the facing surface 54 are disposed in the middle part of the contact area. Therefore, the heat sink 20 is prevented from being inclined with respect to the circuit board 18 with the line L connecting the pair of fastening portions 62 as the axial direction. As a result, the heat sink 20 can be evenly pressed against the circuit board 18. That is, in the present embodiment, the fastening points for attaching the heat sink 20 to the circuit board 18 can be reduced, and the circuit board 18 and the heat dissipating material are separated or the heat dissipating material and the heat sink 20 are separated. Can be suppressed. As a result, the contact thermal resistance between the circuit element 16 and the heat sink 20 can be reduced.

  In the present embodiment, the heat sink 20 is attached to the circuit board 18 via the pair of fastening portions 62, and the direction in which the line L connecting the pair of fastening portions 62 extends coincides with the longitudinal direction of the heat sink 20. Yes. Therefore, the intermediate portion in the longitudinal direction of the heat sink 20 can be evenly pressed against the circuit board 18. As a result, in this embodiment, the heat dissipation efficiency can be improved.

  Furthermore, in this embodiment, since the heat radiating material is in a gel form having thermal conductivity, the heat radiating material is evenly interposed between the circuit board 18 and the heat sink 20. As a result, in this embodiment, the contact thermal resistance between the circuit element 16 and the heat sink 20 can be further reduced.

  Further, as shown in FIGS. 5A and 5B, in this embodiment, a recess 60 that is recessed in a direction away from the circuit board 18 is provided in a portion adjacent to the facing surface 54 in the heat sink 20. . Therefore, when the heat sink 20 is attached to the circuit board 18, the heat dissipating material protruding from between the facing surface 54 and the circuit element 16 is accommodated in the recess 60 (stays in the recess 60). As a result, in the present embodiment, it is possible to suppress the heat dissipation material from protruding between the heat sink 20 and the circuit board 18.

  In the present embodiment, the concave portion 60 includes the first concave portion 60 </ b> A provided between the first leg portion 56 and the facing surface 54 of the heat sink 20, and the second leg portion 58 and the facing surface 54 of the heat sink 20. And a second recess 60B provided between the two. Therefore, the heat dissipation material protruding from between the facing surface 54 and the circuit element 16 is interposed between the contact surface 56A of the first leg portion 56 and the contact surface 56B of the second leg portion 58 and the circuit board 18. Is suppressed. As a result, in the present embodiment, the heat sink 20 can be prevented from tilting with respect to the circuit board 18.

  Next, operations and effects unique to the present embodiment will be described.

  As shown in FIGS. 3 and 5, in the present embodiment, the heat sink 20 and the circuit board 18 are in contact with each other through a heat dissipating material at a portion facing circuit elements (FETs 41 </ b> A to 41 </ b> F and reverse connection prevention FETs 41 </ b> G) that generate significant heat. In addition, the circuit elements (capacitors 40A, 40B, 40C, and 40D) that generate less heat are spaced apart from each other. Thereby, it can suppress that the heat | fever of FET41A-41F and reverse connection prevention FET41G is transmitted to capacitor | condenser 40A, 40B, 40C, 40D via the heat sink 20. FIG.

  In the present embodiment, the FETs 41A to 41F and the reverse connection prevention FET 41G are attached to suppress the heat of the FETs 41A to 41F and the reverse connection prevention FET 41G from being transmitted to the capacitors 40A, 40B, 40C, and 40D via the heat sink 20. Such as separating the circuit board to be mounted from the circuit board to which the capacitors 40A, 40B, 40C, and 40D are attached becomes unnecessary. As a result, in the present embodiment, it is possible to suppress an increase in the number of parts constituting the motor drive control device 34 and an increase in the space for mounting the motor drive control device 34, and as a result, the vehicle motor unit 10 can be reduced in size. Can be planned.

  Further, in the present embodiment, the protrusion 52 of the heat sink 20 is exposed from the upper case 32 side that houses the circuit board 18. Therefore, the heat of the FETs 41 </ b> A to 41 </ b> F and the reverse connection prevention FET 41 </ b> G is radiated from the protrusion 52 of the heat sink 20 toward the outside of the case (upper case 32 and lower case 48) via the heat sink 20. As a result, an increase in temperature near the protrusion 52 of the heat sink 20 is suppressed, and as a result, the amount of heat (the amount of heat transmitted by convection and radiation) transmitted from the portion to the capacitors 40A, 40B, 40C, and 40D is reduced. That is, in the present embodiment, it is possible to further suppress the heat of the FETs 41A to 41F and the reverse connection prevention FET 41G from being transmitted to the capacitors 40A, 40B, 40C, and 40D via the heat sink 20.

  In the present embodiment, the example in which the facing surface of the heat sink 20 and the circuit board 18 are brought into contact with each other via a heat dissipation material has been described. However, the present invention is not limited to this, and the facing surface of the heat sink 20 and the circuit board. It is good also as a structure which made 18 contact directly.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications other than the above can be implemented without departing from the spirit of the present invention. Of course.

DESCRIPTION OF SYMBOLS 10 ... Motor unit for vehicles, 12 ... Motor, 14 ... Output shaft, 18 ... Circuit board, 20 ... Heat sink (heat radiating member), 32 ... Upper case (case), 40A ... Capacitor (control component), 40B ... Capacitor (control) Parts), 40C ... capacitor (control part), 40D ... capacitor (control part), 41A ... FET (heat generation part), 41B ... FET (heat generation part), 41C ... FET (heat generation part), 41D ... FET (heat generation part) , 41E... FET (heat generating component), 41F... FET (heat generating component), 41G... Reverse connection prevention FET (heat generating component), 48 Lower case (case) 52 Protrusion (exposed portion)

Claims (2)

A motor that rotates the output shaft around its axis when energized;
A circuit board on which a heat generating component and a control component for controlling the rotation of the output shaft are mounted;
The circuit board is disposed on the side opposite to the mounting surface of the heat generating component and the control component, and the portion facing the heat generating component is in contact with the circuit board and the portion facing the control component is the circuit board. A heat dissipating member spaced from the
A motor unit for vehicles comprising The circuit board is configured integrally with the motor, and the circuit board is housed in a case,
The vehicle motor unit according to claim 1, wherein an exposed portion that is exposed to the outside of the case is provided at a portion of the heat dissipation member that faces the control component.

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