JP6087123B2 - Brushless motor - Google Patents

Description

  The present invention relates to a brushless motor that is reduced in size in the radial direction.

  For example, a brushless motor is used to drive various devices of a vehicle (for example, a negative pressure pump of a brake device). In recent years, there is a strong demand for improvement in heat resistance and reduction in manufacturing cost as well as downsizing of the apparatus due to vehicle layout restrictions. For this reason, it is necessary to reduce the manufacturing cost as well as the brushless motor used. For example, Patent Document 1 describes a structure that can reduce the manufacturing cost while reducing the size and weight of a brushless motor mounted on a vehicle.

  The brushless motor described in Patent Document 1 is a brushless motor used for an electric brake of an automobile, and includes a cylindrical motor housing, a stator fixed inside the housing, a rotor held rotatably, and a motor. And a bracket attached to the opening of the housing. A cover plate is attached to the opening of the bracket. A control board on which a controller unit for controlling driving of the brushless motor and a sensor unit are mounted is assembled on the inner surface side of the cover plate, and a heat sink is integrally formed on the outer surface side of the cover plate. A connector for connecting the brushless motor and the external device is formed on the peripheral wall of the bracket. The connector is provided with a plurality of terminals and is connected to a terminal drawn from the control board. A coupler of an external device is connected to the connector.

  Further, the brushless motor described in Patent Document 2 has a structure in which heat resistance is improved by providing a gap between the motor body and the control unit. By providing an air layer by this gap, there is no mutual thermal influence between the motor body and the control unit.

JP 2010-104212 A Japanese Patent Laid-Open No. 10-117464

  However, since the brushless motor described in Patent Document 1 has a connector formed on the peripheral wall of the bracket, the connector protrudes radially outward from the outer peripheral surface of the bracket. For this reason, this connector prevents the brushless motor from being downsized in the radial direction. In addition, a switching element such as an FET is brought into contact with the inside of a heat sink disposed at an end portion (bottom portion) in the axial direction to perform heat dissipation. However, since a plurality of switching elements for driving the brushless motor are necessary and have a certain size, directly attaching the switching elements to the heat sink with this structure effectively uses a limited space. This is a negative factor. In this respect as well, the brushless motor described in Patent Document 1 is hindered from being reduced in size in the radial direction. In addition, even if an air layer is provided as in Patent Document 2, even if it is thermally improved, there is no change in the necessity of a plurality of switching elements, and the heat sink is increased in size and reduced in the radial direction. Is inhibited.

  In such a background, an object of the present invention is to provide a brushless motor that can reduce the radial size of a brushless motor including a switching element and has excellent heat resistance.

The invention described in claim 1 includes a bottomed cylindrical motor housing having a bottom portion on one side and an opening on the other side, a stator disposed inside the motor housing, and an inner side of the stator. A rotor disposed rotatably; an end cap disposed in the opening of the motor housing; a separation wall disposed on a side of the end cap opposite to the rotor; and the end cap of the separation wall A heat sink disposed on the opposite side of the heat sink, a control circuit board disposed between the separation wall and the heat sink, a switching element mounted on the control circuit board, and the heat sink to which the switching element is attached and the heat sink And a mounting plate disposed in a space between the control circuit board and the heat sink. -Up and the separation wall is disposed at a distance, the heat sink, whereas a plurality of heat radiation fins on the side is integrally formed, the other side is attached to a member extending from the separation wall, the one The brushless motor is characterized in that a lead-out portion for drawing out a lead wire connected to the control circuit board is provided at a location where the heat radiating fin on the side is not formed .

  According to a second aspect of the present invention, in the first aspect of the present invention, the switching element is attached to the attachment plate in an axially standing state.

  According to a third aspect of the present invention, in the second aspect of the present invention, the mounting plate includes a side surface portion to which the switching element is mounted in an axial direction and a bottom surface portion that is thermally coupled to the heat sink. It is characterized by providing.

The invention according to claim 4 is the invention according to any one of claims 1 to 3 , wherein the control circuit board is attached to the separation wall with a gap.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the heat sink and the mounting plate are in contact with each other through a heat conductive sheet.

The invention according to claim 6 is the invention according to any one of claims 1 to 5 , wherein the end cap, the motor housing, the member extending from the separation wall, and the heat sink include an O-ring. It is characterized by being connected via.

The invention according to claim 7 is the invention according to any one of claims 1 to 6 , wherein the center of the separation wall has an opening facing the rotating shaft, and the rear end surface of the rotating shaft is A magnet is disposed, and a rotation detecting Hall element is provided on the side of the control circuit board facing the rotation axis.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to achieve size reduction of the radial direction of the brushless motor which incorporated the switching element, the brushless motor excellent in heat resistance is provided.

It is sectional drawing of embodiment. It is a perspective view of an embodiment.

(Constitution)
A brushless motor 100 is shown in FIGS. The brushless motor 100 is a brushless motor used for driving a negative pressure pump mounted on a vehicle, and has an 8-pole 9-slot structure. The brushless motor 100 is supported by a bottomed cylindrical motor housing 101, a stator 102 fitted and fixed inside the motor housing 101, and a rotatable state with respect to the stator 102 inside the stator 102. And a rotor 106.

  The bottomed cylindrical motor housing 101 has a bottom 101a on one side (upper side in FIG. 1) and an opening on the other side (lower side in FIG. 1). A boss 101b protruding in the axial direction is formed at the center of the bottom 101a. The boss portion 101b has a structure in which a short cylindrical portion protrudes in the axial direction. A hole for inserting the rotary shaft 109 is formed in the center of the boss portion 101b, and a bearing 108 for rotatably supporting the rotary shaft 109 (rotor 106) is press-fitted and fixed inside the boss portion 101b. ing.

  A stator 102 is fitted and fixed inside the motor housing 101. The stator 102 includes a stator core 103, an insulator 104 attached to the stator core 103, and a coil 105 wound around the stator core 103. The stator core 103 is formed by laminating a plurality of soft magnetic steel plates (for example, silicon steel plates, electromagnetic steel plates, etc.), and is formed with pole teeth portions that project from an annular yoke portion in the axial center direction. An insulator 104 is attached to the stator core 103, and a coil 105 constituting a field coil is wound around the pole tooth portion of the stator core 103 via the insulator 104. A coil terminal (not shown) of the coil 105 is connected to a terminal pin (not shown) disposed on the insulator 104.

  The rotor 106 is disposed inside the stator 102 and is supported by a pair of bearings 108 and 114 so as to be rotatable with respect to the stator 102. The rotor 106 includes a sleeve 110 having a hollow cylindrical shape, a hollow cylindrical rotor core 111 formed of a soft magnetic material, and a hollow cylindrical rotor magnet 112 fixed to the outer peripheral surface of the rotor core 111. The rotor magnet 112 is magnetized in a magnetic pole structure whose polarity is alternately reversed with SNSN... Along the circumferential direction. A rotation shaft 109 is press-fitted and fixed to the center of the sleeve 110. One end of the rotary shaft 109 is provided with an involute spline process 109a for coupling with a rotor (not shown) of a vane pump constituting a negative pressure pump (not shown). In addition, the structure which couple | bonds the rotating shaft 109 and the rotor of the vane pump which is not shown in figure is not limited to the structure illustrated if it can transmit rotation of the rotating shaft 109 to the rotor of a vane pump.

  An end cap 113 is attached inside the opening of the motor housing 101. The end cap 113 has a disk portion 113a and a cylindrical portion 113b extending in the axial direction from the outer edge thereof. At the center of the disk portion 113a of the end cap 113, a boss portion 113c protruding in the axial direction is formed. A hole for inserting the rotating shaft 109 is formed in the center of the boss portion 113c, and a bearing 114 for rotatably supporting the rotor 106 is press-fitted and fixed inside the boss portion 113c. The end cap 113 is fixed to the motor housing 101 by a caulking structure 101 c at the end of the motor housing 101. An O-ring 131 is inserted between the motor housing 101 and the end cap 113.

  A coil spring 132 for applying a preload is mounted between the sleeve 110 and the bearing 108, and a cylindrical collar 133 is disposed between the sleeve 110 and the bearing 114. With this structure, a preload is urged to the bearing 108 by the coil spring 132 and a preload is also urged to the bearing 114 by the collar 133.

  A separation member 116 having a bottomed cylindrical structure is attached to the inside of the cylindrical portion 113b of the end cap 113 with a screw or the like. The separation member 116 has a disk-shaped separation wall 116a having an opening at the center, and a cylindrical portion 116b extending in the axial direction from the outer edge of the separation wall 116a. The separation wall 116a is located away from the disk portion 113a of the end cap 113 in the axial direction, and an air layer 117 is formed between the separation wall 116a and the disk portion 113a. The outer diameter of the separating member 116 (the separating wall 116a) is the same as or smaller than the outer diameter of the brushless motor 100. A control circuit board 118 is attached to the inside of the cylindrical portion 116 b of the separating member 116.

  The control circuit board 118 is an electronic board on which a circuit for driving the brushless motor 100 is mounted. A wiring pattern is formed on both surfaces of the control circuit board 118, and electronic components are mounted on both surfaces of the control circuit board 118, increasing the mounting density of the electronic components. The control circuit board 118 is fixed to the separation wall 116a by screws so as to be disposed at a position away from the separation wall 116a in the axial direction. A structure in which the control circuit board 118 is fixed to the disk portion 113a of the end cap 113 by screwing across the separation wall 116a is also possible.

  A hall element 119 is disposed at the axial center of the control circuit board 118, and the end of the rotary shaft 109 penetrating the opening in the center of the separation wall 116a is located at a position facing the hall element 119 with a gap. . A magnet 120 is attached to the end of the rotating shaft 109 facing the Hall element 119. When the rotating shaft 109 rotates, the magnet 120 rotates, and the rotation is detected by the Hall element 119.

  A switching element 121 such as an FET is attached to the control circuit board 118 opposite to the rotation shaft 109 (lower side in FIG. 2) in an axial direction. Further, a metal attachment plate 122 that functions as a radiator is attached to the side of the control circuit board 118 where the switching element 121 is attached. The mounting plate 122 includes a side surface portion 122 a extending in the axial direction to which the switching element 121 is mounted in an axial state, and a bottom surface portion 122 b that is thermally coupled to the heat sink 124. The mounting plate 122 is disposed in a space 129 between the control circuit board 118 and the heat sink 124.

  In this example, the mounting plate 122 has a substantially U-shape when viewed from the direction perpendicular to the axis, and the bottom surface of the mounting plate 122 is thermally coupled to the heat sink 124 via the thermal conductive sheet 123. The outer diameter of the heat sink 124 viewed from the axial direction is the same as or smaller than the outer diameter of the brushless motor 100. In this structure, heat generated in the switching element 121 is transmitted to the heat sink 124 via the mounting plate 122 and is radiated to the outside from the heat sink 124.

  The mounting plate 122 is a member that functions as a radiator of the switching element 121 and is made of a metal material having excellent thermal conductivity such as copper or aluminum. The switching element 121 has a heat radiating surface, and is attached to the mounting plate 122 in a state where the heat radiating surface is thermally coupled to the mounting plate 122. In addition, the terminal (lead wire) of the switching element 121 is electrically connected to the wiring pattern of the control circuit board 118. In FIG. 2, one switching element 121 is shown, but there are usually a plurality of switching elements 121. The attachment plate 122 is attached to the control circuit board 118 with screws 135 via spacers 134.

  The shape of the mounting plate 122 viewed from the axial direction may be a structure having a flat surface (122a in this example) to which the switching element 121 is mounted. The shape of the mounting plate 122 viewed from the axial direction can be a polygonal shape such as a quadrangle. In this example, the mounting plate 122 has a side surface portion 122a and a bottom surface portion 122b. The side surface portion 122a is a flat side surface to which the switching element 121 is attached, and the bottom surface portion 122b is in contact with a heat sink 124 described later. As long as there are portions corresponding to the side surface portion 122a and the bottom surface portion 122b, the shape of the mounting plate 122 is not limited to the shape illustrated. The mounting plate 122 in which the switching element 121 is attached to the side surface portion 122 a may be configured so as to stand and be arranged around the rotating shaft 109.

  As shown in the drawing, there are a plurality of side portions 122a (two in this case) of the mounting plate 122, and switching elements other than the reference numeral 121 not shown can be mounted in the same state as the switching element 121. Even if a plurality of switching elements are attached to the side surface portion 122a, each switching element can be arranged in the axial direction as shown in the figure, so that the area occupied in the radial direction of each switching element can be suppressed.

  A heat sink 124 is attached to the opening (lower end in FIG. 1) of the cylindrical portion 116 b of the separating member 116 via an O-ring 125 and is closed. The heat sink 124 has a substantially disk shape, and a plurality of heat radiation fins 124a are integrally formed on one side (outer side) and a recess is formed on the other side (inner side). Between the heat sink 124 and the control circuit board 118, the attachment plate 122 and the switching element 121 attached to the attachment plate 122 are located.

  The bottom surface portion 122 b of the mounting plate 122 is in contact with the heat sink 124 via the heat conductive sheet 123 and is thermally coupled to the heat sink 124. By interposing the heat conductive sheet 123 between the heat sink 124 and the mounting plate 122, the thermal coupling state between the two is improved. The heat conductive sheet 123 also functions as a cushioning material between the heat sink 124 and the mounting plate 122.

  A plurality of through-holes 130 penetrating in the axial direction constituting a lead-out portion for pulling out the lead wire 126 to the outside are formed at a portion of the heat sink 124 where the radiation fins 124a are not formed. The plurality of through holes 130 are holes for drawing the lead wires 126 connected to the control circuit board 118 to the outside, and wire seals 127 are respectively attached to the through holes 130. It is also possible to arrange a connection connector to which wiring from the control circuit board is connected in a portion where the through hole 130 is provided, and connect the wiring from the outside to this connection connector.

An annular groove is formed on the outer peripheral surface of the heat sink 124, and an O-ring 125 is attached to the annular groove. The heat sink 124 is fitted inside the cylindrical portion 116 b of the separating member 116, and the opening of the cylindrical portion 116 b is sealed by the O-ring 125.
A plurality of peripheral portions of the opening portion of the cylindrical portion 116 b of the separating member 116 have a caulking structure 128, whereby the heat sink 124 is fixed to the opening portion of the separating member 116. The position and number of the caulking structure can be determined as appropriate. The means for mounting the heat sink 124 on the motor body side is not limited to caulking, and may be welding, adhesion, screwing, a fitting structure, or the like.

  A flange 107 for mounting the brushless motor 100 to a negative pressure pump (not shown) is fixed to the other end side of the motor housing 101 (on the bottom 101a side in the drawing). An opening through which the boss 101b is inserted is formed in the flange 107, and an annular groove is formed at the periphery of the opening, and an O-ring 136 is attached to the annular groove. The opening is inserted into the boss 101b, and the mounting flange 107 is fixed to the bottom 101a of the motor housing 101 by welding. The brushless motor 100 is fastened to a negative pressure pump (not shown) with a screw (not shown).

(Superiority)
According to the above structure, the brushless motor 100 incorporating the switching element 121 can be reduced in the radial direction, and the brushless motor 100 having excellent heat resistance can be obtained. In particular, by providing a lead-out portion for drawing out the lead wire 126 behind the heat sink 124 (on the end face side in the axial direction), the size in the radial direction can be reduced. Further, by attaching the switching element 121 to the attachment plate 122 in a standing state, the shape of the heat sink 124 in the radial direction can be reduced in size. In addition, by providing the separation wall 116a and further securing the air layer 117, a structure in which the motor main body portion such as the stator 102 and the rotor 106 and the control circuit board 118 side hardly affect each other with heat is unlikely to occur. can get.

  Further, the bottom surface portion 122b of the mounting plate 122 is brought into surface contact with the heat sink 124 via the heat conductive sheet 123, whereby heat conduction from the mounting plate 122 to the heat sink 124 can be favorably performed, and heat dissipation of the switching element 121 is achieved. Can be done effectively. Further, by providing a lead wire 126 lead-out portion at a portion of the end surface of the heat sink 124 where the heat dissipating fins 124a are not formed, the heat dissipation effect can be maintained while the lead wire 126 is not drawn out in the radial direction. Can do.

  By attaching the control circuit board 118 in a state of being separated from the separation wall 116a, it is possible to obtain a structure that suppresses the thermal influence between the motor body and the control unit while having a simple structure. An opening is provided in the center of the separation wall 116a, and the rotating shaft 109 projects from the opening to the control circuit board 118 side. By detecting, a structure capable of detecting the rotation of the rotor 106 is obtained while ensuring the thermal blocking structure by the separation wall 116a.

(Other)
Although the brushless motor for driving the negative pressure pump has been described in the above-described embodiment, the application range of the brushless motor using the present invention is not limited to the negative pressure pump.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

  The present invention can be used for a brushless motor.

DESCRIPTION OF SYMBOLS 100 ... Brushless motor, 101 ... Motor housing, 101a ... Bottom part, 101b ... Boss part, 101c ... Caulking structure, 102 ... Stator, 103 ... Stator core, 104 ... Insulator, 105 ... Coil, 106 ... Rotor, 107 ... Flange, 108 ... Bearing 109, rotating shaft (shaft) 109a, involute spline processing, 110, sleeve, 111, rotor core, 112, rotor magnet, 113, end cap, 113a, disk portion, 113b, cylindrical portion, 113c, boss portion, 114 DESCRIPTION OF SYMBOLS ... Bearing, 116 ... Separation part, 116a ... Separation wall, 116b ... Cylindrical part, 117 ... Air layer, 118 ... Control circuit board, 119 ... Hall element, 120 ... Magnet, 121 ... Switching element, 122 ... Mounting plate, 122a ... Side part, 122 DESCRIPTION OF SYMBOLS ... Bottom part, 123 ... Thermal conductive sheet, 124 ... Heat sink, 124a ... Radiation fin, 125 ... O-ring, 126 ... Lead wire, 127 ... Wire seal, 128 ... Caulking structure, 129 ... Between control circuit board 118 and heat sink 124 130 ... through hole, 131 ... O ring, 132 ... coil spring, 133 ... collar, 134 ... spacer, 135 ... screw, 136 ... O ring.

Claims (7)

A bottomed cylindrical motor housing with a bottom on one side and an opening on the other;
A stator disposed inside the motor housing;
A rotor rotatably disposed inside the stator;
An end cap disposed in the opening of the motor housing;
A separation wall disposed on the opposite side of the end cap from the rotor;
A heat sink disposed on the opposite side of the separation wall from the end cap;
A control circuit board disposed between the separation wall and the heat sink;
A switching element mounted on the control circuit board;
The switching element is mounted and thermally coupled to the heat sink, and includes a mounting plate disposed in a space between the control circuit board and the heat sink;
The end cap and the separation wall are spaced apart;
In the heat sink , a plurality of heat radiation fins are integrally formed on one side, the other side is attached to a member extending from the separation wall, and the heat radiation fins on the one side are not formed at the locations. A brushless motor comprising a lead-out portion for pulling out a lead wire connected to a control circuit board.   The brushless motor according to claim 1, wherein the switching element is attached to the attachment plate in an axially standing state.   The brushless motor according to claim 2, wherein the mounting plate includes a side surface portion to which the switching element is mounted in an axial direction and a bottom surface portion that is thermally coupled to the heat sink. The brushless motor according to any one of claims 1 to 3 , wherein the control circuit board is attached with a gap in the separation wall. The brushless motor according to any one of claims 1 to 4 , wherein the heat sink and the mounting plate are in contact with each other via a heat conductive sheet. The brushless according to any one of claims 1 to 5 , wherein the end cap, the motor housing, the member extending from the separation wall, and the heat sink are coupled to each other through an O-ring. motor. There is an opening facing the rotation axis in the center of the separation wall, a magnet is disposed on the rear end surface of the rotation shaft, and a rotation detecting Hall element is provided on the side of the control circuit board facing the rotation axis. brushless motor according to any one of claims 1 to 6, characterized in that There are features.

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