JP5535543B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor having a motor shaft that is rotated by an electric current and a bottomed cylindrical motor body that supports the motor shaft.

  As a drive source of a wiper device or a power window device provided in a vehicle, that is, a wiper motor or a power window motor, an electric motor with a speed reduction mechanism is often used as a unit by attaching a speed reduction mechanism to a motor body. Such an electric motor with a speed reduction mechanism is such that the rotation of the motor shaft (armature shaft) of the motor body is reduced by the speed reduction mechanism and output from the output shaft, so that a small and large output can be obtained.

  In an electric motor with a speed reduction mechanism, a so-called brush motor is often used as a motor body. As shown in Patent Document 1, for example, a motor with a brush includes a commutator (commutator) fixed to a motor shaft, and a plurality of brushes that are in sliding contact with the commutator. Each brush is held by a brush box (brush holder) so as to be movable forward and backward, and each brush box is fixed to a brush holder main body (holder base) at a fixed leg portion. A gear case (base fixing member) that houses the speed reduction mechanism is fixed to the motor body, and the brush holder body is also housed in a portion where the gear case is attached to the motor. Then, a drive current is supplied to each brush, and the drive current commutated by the brush and the commutator at a predetermined timing is supplied to the motor body, whereby the motor shaft rotates in a predetermined direction, and the rotation is reduced by the reduction mechanism. It is decelerated and output from the output shaft.

JP 2008-252970 A

  In a conventional electric motor with a speed reduction mechanism, a gear case is formed of a metal having a high thermal conductivity such as an aluminum alloy, and heat generated by the brush is radiated to the outside through the gear case.

  However, in the conventional electric motor with a speed reduction mechanism, in order to prevent a short circuit between the metal brush box containing the positive and negative brushes and the metal gear case, the brush box is fixed between the fixed leg portion and the inner surface of the gear case. Since the gap is provided, the heat generated by the brush is transferred to the gear case through the air layer between the fixed leg of the brush box and the inner surface of the gear case, so that the heat generated by the brush is sufficient. Could not be transmitted to the gear case. Therefore, in some cases, the heat of the brush is transmitted to the inside of the gear case through the air layer, and there is a problem that the speed reduction mechanism, the control board, and the like housed in the gear case may be affected by the heat.

  An object of the present invention is to provide an electric motor that improves heat dissipation of the brush by efficiently transmitting heat generated by the brush to a base fixing member.

The electric motor of the present invention is an electric motor having a motor shaft that is rotated by an electric current and a bottomed cylindrical motor body that supports the motor shaft, and a commutator fixed to the motor shaft, A plurality of metal brush holding members fixed to a holder base in a fixing portion, a plurality of brushes held by the corresponding brush holding members and in sliding contact with the commutator, and an opening of the motor body, covering the holder a base fixing member base is fixed, provided between the brush holding member and the base fixing member, have a thermally conductive member in contact with at least a portion of the base fixing member and the brush holding member The holder base is provided with a holding wall that surrounds and holds the outer periphery of the thermally conductive member, and the base fixing member has an inner wall of the holding wall. Convex portions are provided is inserted in contact with the thermally conductive member to you wherein Rukoto.

  In the electric motor according to the aspect of the invention, the fixing portion includes a fixing leg portion of the brush holding member, the heat conductive member is provided between the base fixing member and the holder base, and the base fixing member and the It contacts the fixed leg part.

  In the electric motor of the present invention, the heat conductive member is formed thicker than the gap between the base fixing member and the holder base, and the base fixing member and the holder base are compressed in the compressed state. It arrange | positions between.

  The electric motor according to the present invention is characterized in that the heat conductive member is formed of a heat conductive resin having an insulating property.

  The electric motor of the present invention is characterized in that the heat conductive member is formed of an acrylic material.

  The electric motor of the present invention is characterized in that the heat conductive member is formed of a heat conductive sheet.

  The electric motor according to the present invention is characterized in that the thermally conductive member is insulative and is formed by applying to at least a part of the brush holding member.

  The electric motor of the present invention is characterized in that a rib portion protruding toward the holder base is provided on the tip surface of the convex portion.

  In the electric motor of the present invention, the rib portion has a cross shape.

  The electric motor of the present invention is characterized in that each of the brush holding members is provided with four fixed leg portions, and each of the fixed leg portions is arranged at four corners of the front end surface of the convex portion partitioned by the rib portion. And

  The electric motor of the present invention is characterized in that a side surface of the rib portion that is continuous with the front end surface of the convex portion is inclined with respect to the front end surface.

  The electric motor of the present invention is characterized in that a fin for heat dissipation is provided on the outer surface of the base fixing member.

  The electric motor of the present invention is characterized in that the electric motor is an electric motor with a speed reduction mechanism used in a vehicle.

  The electric motor of the present invention is a continuous rated motor used in a vehicle, and the base fixing member has a cover shape.

  The electric motor of the present invention is a fan motor that is used as a drive source of a radiator cooling device for a vehicle, and the base fixing member has a cover shape.

  The electric motor of the present invention is a wiper motor that is used as a drive source for a wiper device of a vehicle, and the base fixing member is a gear case that houses the holder base.

  According to the present invention, the heat conductive member is provided between the base fixing member and the holder base, and at least a part of the brush holding member that holds the brush and the inner surface of the base fixing member are brought into contact with the heat conductive member. Since it did in this way, the heat which the brush emitted can be efficiently transmitted to a base fixing member via a heat conductive member, and the heat dissipation of a brush can be improved. As the heat conductive member, one formed of a heat conductive resin or an acrylic material can be used. Further, the present invention can be applied to a wiper motor or a fan motor used as a drive source for a vehicle wiper device or a vehicle radiator cooling device.

  According to the present invention, the thickness of the heat conductive member is formed thicker than the gap between the base fixing member and the holder base, and the heat conductive member is disposed between the base fixing member and the holder base in a compressed state. Therefore, the heat conductive member can be reliably brought into contact with the fixing portion of the brush holding member and the inner surface of the base fixing member to further improve the heat dissipation of the brush.

According to the present invention, provided a retaining wall Horudabe scan, since by this retention wall to hold surround the outer periphery of the heat conductive member, the heat conduction to securely hold the heat conductive member to Horudabe scan sexual member can be prevented Horudabe scan or Rahazureru.

According to the present invention, since the convex portion that is inserted inside the holding wall is provided on the base fixing member, and this convex portion is brought into contact with the heat conductive member, the base fixing member is securely attached to the heat conductive member. Can be contacted.

  According to the present invention, since the cross-shaped rib portion protruding toward the holder base is provided on the tip surface of the convex portion provided on the base fixing member, the contact area between the convex portion and the heat conductive member is increased. can do. Thereby, the heat conduction efficiency between a base fixing member and a heat conductive member can be improved, and the heat dissipation of a brush can further be improved.

  According to the present invention, each of the brush holding members is provided with four fixed leg portions, and the respective fixed leg portions are arranged at the four corners of the front end surface of the convex portion defined by the rib portions. The heat conductive member can be sandwiched between the fixed leg portions so that the heat conductive member can be brought into contact with the base fixing member more reliably.

  According to the present invention, since the side surface of the rib portion that is continuous with the front end surface of the convex portion is inclined with respect to the front end surface, the gap generated between the heat conductive member and the base portion of the rib portion is reduced. The heat conductivity by the heat conductive member can be increased.

  According to the present invention, the fins for heat dissipation are provided on the outer surface of the base fixing member. Therefore, the heat of the brush transmitted to the base fixing member via the heat conductive member is efficiently radiated to the outside, and the brush The heat dissipation can be further enhanced.

It is a perspective view which shows the wiper motor which is one embodiment of this invention. It is sectional drawing which shows the internal structure of the wiper motor shown in FIG. It is a front view which shows the detail of the brush unit shown in FIG. It is sectional drawing which shows the detail of the attachment part to the holder base of a brush holder. (A) is the perspective view which looked at the holder base before mounting | wearing a heat conductive sheet from the back surface side, (b) is a perspective view which shows the mounting state to the holder base of a heat conductive sheet. It is a perspective view which shows the inside of the motor attaching part of a gear case. It is explanatory drawing which shows the positional relationship of the fixed leg part of a brush holder, and the rib part provided in the convex part. It is sectional drawing which follows the AA line in FIG. It is a perspective view which shows the fin formed in the outer surface of the motor attaching part of a gear case.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A wiper motor 11 as an electric motor with a speed reduction mechanism shown in FIG. 1 is used as a drive source of a wiper device provided in a vehicle such as an automobile, and includes a motor body 12 and a speed reducer 13. The speed reducer 13 is attached to the motor main body 12, whereby the wiper motor 11 is made into one unit. The wiper motor 11 is fixed to a vehicle body (not shown) at an attachment leg 13 a provided on the speed reducer 13.

  In the wiper motor 11, a so-called brush motor is used as the motor body 12. The yoke 14 of the motor body 12 is formed into a bottomed cylindrical shape by pressing a thin steel plate or the like, and a pair of magnets magnetized with N and S poles radially inward on the inner surface thereof (Permanent magnet) 15 is fixed.

  An armature (armature) 16 is accommodated in the yoke 14. The armature 16 includes a motor shaft (armature shaft) 17 at its axis, and one end of the motor shaft 17 is supported by a bearing 18 fixed to the bottom of the yoke 14. Thereby, the armature 16 is rotatable inside the yoke 14 together with the motor shaft 17. An armature core (armature core) 21 is fixed to the motor shaft 17, and this armature core 21 faces each magnet 15 through a minute gap (air gap). The armature core 21 is provided with a plurality of slots 21a arranged in the rotational direction, and a plurality of armature coils (armature windings) 22 are attached to the slots 21a by overlapping winding of conductive wires.

  A commutator (commutator) 23 is fixed to the motor shaft 17 adjacent to the armature core 21. The commutator 23 is provided with a plurality of segment pieces 23a arranged in the direction of rotation at equal intervals while being insulated from each other, and the coil ends of the corresponding armature coils 22 are electrically connected to the segment pieces 23a, respectively. Has been. When the armature 16, that is, the motor shaft 17 rotates, the commutator 23 also rotates together with the motor shaft 17.

  On the other hand, the speed reducer 13 includes a gear case (frame) 31 as a base fixing member, and has a structure in which a worm gear mechanism 32 as a speed reduction mechanism is accommodated in the gear case 31.

  The gear case 31 is opened in a direction perpendicular to the axial direction of the motor shaft 17 (upward direction in FIG. 2) by a resin material in which a metal material having a high thermal conductivity such as an aluminum alloy or a material having a high thermal conductivity is mixed. It is formed in a bathtub shape, and a motor mounting portion 33 is integrally provided on one side thereof. Further, a resin cover 34 is attached to the gear case 31 by a plurality of screw members 35, and the opening of the gear case 31 is closed by the cover 34.

  The motor mounting portion 33 is formed in a bottomed cylindrical shape having a substantially oval cross section that opens toward the motor main body 12 side (left side in FIG. 2), and is combined with the opening end of the yoke 14 at the opening end. In this state, it is fixed to the yoke 14 by the screw member 36. Thereby, the gear case 31 is attached to the motor body 12. The front end portion of the motor shaft 17 protruding from the yoke 14 protrudes into the gear case 31 through a through hole 33 b formed in the bottom wall 33 a of the motor mounting portion 33, and is fixed to the motor shaft 17. The commutator 23 is disposed inside the motor mounting portion 33.

  A pair of bearings 37 and 38 are fixed inside the gear case 31, and the motor shaft 17 is rotatably supported by the gear case 31 at an intermediate portion and a tip portion of the bearings 37 and 38.

  A brush unit 41 is mounted inside the motor mounting portion 33 where the commutator 23 is disposed. That is, the brush unit 41 is accommodated in the gear case 31 in the motor mounting portion 33.

  FIG. 3 is a front view showing details of the brush unit shown in FIG. 2, and this brush unit 41 has a holder base 42 made of resin.

  The holder base 42 includes a guide wall portion 42a and a base portion 42b, and has a structure in which these are integrally formed of a resin material. The guide wall portion 42a is formed in a substantially oval cylindrical shape corresponding to the cross-sectional shape of the motor mounting portion 33 and the yoke 14, and the outer surface of the guide wall portion 42a contacts the inner surface of the motor mounting portion 33 so that the holder base 42 is attached to the motor mounting portion. Positioning is performed in the radial direction inside 33. On the other hand, the base portion 42b is formed in a plate shape perpendicular to the axial direction of the motor shaft 17 and is disposed on one end side of the guide wall portion 42a, and is opposed to the bottom wall 33a of the motor mounting portion 33 with a predetermined interval. doing. An insertion hole 42c is provided in the shaft center of the base portion 42b, and the motor shaft 17 and the commutator 23 are inserted through the insertion hole 42c and penetrate the base portion 42b.

  A brush holder 43 as a pair of brush holding members is fixed to the base portion 42b. Each of these brush holders 43 is made of metal formed in a box shape with one end opened by bending a copper plate or the like, and each of the brush holders 43 is disposed with its axial direction directed toward the center of the insertion hole 42c. The brush holders 43 shift the phase by 90 degrees in the rotation direction of the motor shaft 17 around the insertion hole 42c, that is, the axis of the motor shaft 17, and both the arc-shaped portions 42d and the straight portions 42e of the base portion 42b. Are arranged symmetrically in FIG. 3 adjacent to the boundary portion.

  Each brush holder 43 is provided with a brush 44 formed of a conductor such as carbon or graphite. These brushes 44 are respectively held by the corresponding brush holders 43 so as to be movable forward and backward, and are urged by springs 45 provided inside the brush holders 43 to elastically contact (sliding contact) with the outer peripheral surface of the commutator 23. doing.

  A pair of power supply terminals 46 are arranged on the base part 42 b, and the pigtails 44 a of the brushes 44 are connected to the corresponding power supply terminals 46. A choke coil (noise prevention element) 47 is connected between the pigtail 44 a of each brush 44 and the power supply terminal 46.

  With such a structure, when a drive current is supplied to the power supply terminal 46, the drive current commutated at a predetermined timing by each brush 44 and the commutator 23 is supplied to the armature coil 22, and electromagnetic force is applied to the armature 16. This occurs and the motor shaft 17 rotates.

  The worm gear mechanism 32 accommodated in the gear case 31 includes a worm 32a and a worm wheel 32b. The worm 32 a is integrally formed on the outer peripheral surface of the portion of the motor shaft 17 that protrudes into the gear case 31, and rotates together with the motor shaft 17. On the other hand, the worm wheel 32b is rotatably accommodated in the gear case 31, and meshes with the worm 32a at the outer peripheral portion thereof.

  The reducer 13, that is, the output shaft 48 of the wiper motor 11, is fixed to the shaft center of the worm wheel 32b. The tip of the output shaft 48 protrudes outside from the gear case 31 and is connected to the link mechanism of the wiper device (not shown) at the tip. Thus, when the motor body 12 is operated, the rotation of the motor shaft 17 is decelerated by the worm gear mechanism 32 including the worm 32a and the worm wheel 32b and transmitted to the output shaft 48, and output from the output shaft 48 toward the wiper device. Is done.

  In order to control the operation of the motor body 12, a control board 51 is accommodated in the gear case 31. Although not shown in detail, the control board 51 has a function as a so-called microcomputer in which a plurality of electronic components such as a CPU, a memory, and an FET are mounted on the board, and is attached to the back surface of the cover 34. It is accommodated in the gear case 31 in the state where it is placed.

  A pair of lead members 52 (only one is shown in FIG. 2) is embedded in the cover 34. When the cover 34 is attached to the gear case 31, the leading ends of these lead members 52 are connected to the respective power supply terminals 46 arranged on the holder base 42. Accordingly, each power supply terminal 46 is electrically connected to the control board 51 by the lead member 52. The cover 34 is provided with a connector 53, and the control board 51 is connected to a power source (not shown) such as a battery mounted on the vehicle or a wiper switch (not shown) via the connector 53. Yes. And the control board 51 adjusts the electric power supplied from a power supply based on the signal from a wiper switch etc., supplies it to the motor main body 12, and controls the action | operation of the said motor main body 12. FIG.

  Reference numeral 54 denotes a partition member attached to the gear case 31 in order to isolate the control board 51 from the worm gear mechanism 32.

  FIG. 4 is a cross-sectional view showing details of the attachment portion of the brush holder to the holder base.

  In the wiper motor 11, a heat conductive sheet 61 as a heat conductive member is provided between the base portion 42 b of the holder base 42 and the bottom wall 33 a of the motor mounting portion 33 of the gear case 31 in order to improve the heat dissipation of each brush 44. The heat generated by the brush 44 is transmitted to the gear case 31 through the heat conductive sheet 61.

  FIG. 5A is a perspective view of the holder base before the heat conductive sheet is mounted from the back side, and FIG. 5B is a perspective view showing a mounting state of the heat conductive sheet to the holder base. .

  A pair of seats corresponding to the respective brush holders 43 are mounted on the surface of the base portion 42b of the holder base 42 opposite to the surface on which the brush 44 is disposed, that is, the surface facing the bottom wall 33a of the motor mounting portion 33. A part 62 is provided. Each of the seat mounting portions 62 has a trapezoidal shape that protrudes toward the first-stage bottom wall 33a from the outer surface of the base portion 42b, and has a rectangular outer shape. A holding wall 63 is provided on the outer periphery of the sheet mounting portion 62 along the outer periphery. The holding wall 63 protrudes toward the bottom wall 33 a from the seat mounting portion 62 and surrounds the seat mounting portion 62.

  Each brush holder 43 is provided with fixed leg portions 43a as four fixed portions. These fixed leg portions 43a are respectively inserted into fixing holes 64 formed in the seat mounting portion 62 of the base portion 42b (only two are shown in FIG. 4), and pass through the base portion 42b and the seat mounting portion 62. ing. Then, by bending the tip of each fixed leg 43a, each brush holder 43 is fixed to the base 42b, and the tip of the fixed leg 43a of each brush holder 43 is disposed on the seat mounting portion 62. The

  The heat conductive sheet 61 is formed into a square sheet having a size corresponding to the sheet mounting portion 62 by acrylic rubber, which is an acrylic material that does not contain or discharge siloxane gas. Further, the thermal conductivity of the heat conductive sheet 61 is 2.1 (W / mk), which is higher than the thermal conductivity of air, 0.0241 (W / mk).

  As shown in FIG. 5B, the heat conductive sheet 61 is disposed on the sheet mounting portion 62 so as to cover the distal end portion of the fixed leg portion 43 a of the brush holder 43. One surface of the heat conductive sheet 61 mounted on the sheet mounting portion 62 is in contact with the tip of each fixed leg portion 43 a of the brush holder 43. Further, the heat conductive sheet 61 mounted on the sheet mounting portion 62 is surrounded by the holding wall 63 at the outer peripheral portion (particularly, the four corner portions). Thereby, the heat conductive sheet 61 is held by the sheet mounting portion 62 by the holding wall 63, and is prevented from being detached from the mounting portion 62.

  As described above, in the wiper motor 11, the holding wall 63 is provided in the sheet mounting portion 62, and the holding wall 63 surrounds and holds the outer periphery of the heat conductive sheet 61. It is possible to prevent the thermal conductive sheet 61 from being detached from the sheet mounting portion 62 by being securely held by the mounting portion 62.

  The heat conductive sheet 61 is not limited to acrylic rubber, but is an acrylic material other than acrylic rubber, a heat conductive resin material obtained by blending a filler such as carbon fiber with silicon rubber, nylon resin, or the like, or an olefin type. You may make it form with resin, an olefin type thermoplastic elastomer, etc. Moreover, as the heat conductive sheet 61, a sheet having electrical insulation and a heat conductivity of 0.1 (W / mk) to 10 (W / mk) is preferable.

  FIG. 6 is a perspective view showing the inside of the motor mounting portion of the gear case.

  A pair of convex portions 65 are provided on the bottom wall 33 a of the motor mounting portion 33 corresponding to the sheet mounting portion 62 provided on the holder base 42. Each of the convex portions 65 is formed integrally with the gear case 31, that is, the bottom wall 33 a, and has a trapezoidal shape that protrudes from the bottom wall 33 a toward the motor body 12, that is, the holder base 42. Each convex portion 65 has a rectangular shape whose outer shape is slightly smaller than that of the seat mounting portion 62.

  When the brush unit 41, that is, the holder base 42 is mounted on the motor mounting portion 33, each convex portion 65 is inserted inside the corresponding holding wall 63 and faces the corresponding sheet mounting portion 62 with a predetermined interval, The front end surface 65a contacts the other surface of the heat conductive sheet 61 mounted on the sheet mounting portion 62.

  Here, the thickness of the heat conductive sheet 61 is formed to be thicker than the gap between the sheet mounting portion 62 of the holder base 42 and the tip surface 65 a of the convex portion 65 of the motor mounting portion 33. Therefore, the heat conductive sheet 61 is sandwiched between the sheet mounting portion 62 and the tip surface 65a of the convex portion 65, and is disposed in a compressed state so that the thickness thereof is reduced by about 20 to 30%. Thereby, the heat conductive sheet 61 reliably contacts the fixed leg portion 43 a of the brush holder 43 and the front end surface 65 a of the convex portion 65 of the motor mounting portion 33.

  As described above, in the wiper motor 11, the convex portion 65 protruding toward the holder base 42 is provided on the gear case 31, and the tip surface 65 a of the convex portion 65 is brought into contact with the heat conductive sheet 61. 31 can be reliably brought into contact with the heat conductive sheet 61.

  In the wiper motor 11, the thickness of the heat conductive sheet 61 is formed to be thicker than the gap between the sheet mounting portion 62 and the front end surface 65 a of the convex portion 65, so that the heat conductive sheet 61 is formed between the sheet mounting portion 62 and the convex portion 65. Since the heat conductive sheet 61 is disposed in a compressed state by being sandwiched between the front end surface 65a of the brush member 43, the heat conductive sheet 61 can be reliably brought into contact with the fixed leg portion 43a of the brush holder 43 and the convex portion 65 of the gear case 31. it can.

  A rib portion 66 is provided on the tip surface 65a of each convex portion 65 in order to enlarge the contact area of the convex portion 65 with the heat conductive sheet 61. The rib portion 66 is formed in a cross-shaped rib shape that protrudes toward the holder base 42 from the tip surface 65 a of the convex portion 65.

  FIG. 7 is an explanatory view showing the positional relationship between the fixed leg portion of the brush holder and the rib portion provided on the convex portion, and FIG. 8 is a cross-sectional view taken along the line AA in FIG.

  As shown in FIG. 7, the tip portions of the fixed leg portions 43 a of the brush holder 43 are disposed at the four corners of the corresponding sheet mounting portion 62. On the other hand, the cross-shaped rib portion 66 formed on the tip surface 65a of the convex portion 65 is disposed in a cross-shaped gap formed between the adjacent fixed leg portions 43a. That is, the fixed leg portions 43 a of the brush holder 43 are arranged at the four corners of the tip end surface 65 a of the convex portion 65 defined by the cross-shaped rib portions 66. Thereby, the heat conductive sheet 61 can be pinched | interposed by the fixed leg part 43a and the rib part 66 which protrude in the mutually opposite direction, and can be made to contact | adhere to the fixed leg part 43a and the rib part 66 reliably.

  With this structure, even if the motor body 12 is operated and the brush 44 that is in sliding contact with the commutator 23 generates heat in the wiper motor 11, the heat is transferred from the brush holder 43, that is, the fixed leg 43 a via the heat conductive sheet 61. Then, it is transmitted to the convex portion 65, that is, the gear case 31, and is radiated from the gear case 31 to the outside.

  As described above, in the wiper motor 11, the heat conductive sheet 61 is disposed between the convex portion 65 of the gear case 31 and the sheet mounting portion 62 of the holder base 42, and the fixed leg portion 43 a and the convex portion 65 of the brush holder 43 are arranged. Since the tip surface 65a is brought into contact with the heat conductive sheet 61, the heat generated by the brush 44 can be transmitted to the gear case 31 by the heat conductive sheet 61 instead of the air layer. Thereby, the heat of the brush 44 can be efficiently transmitted to the gear case 31, and the heat dissipation of the brush 44 can be enhanced.

  In the wiper motor 11, since the cross-shaped rib portion 66 protruding toward the holder base 42 is provided on the tip surface 65 a of the convex portion 65 provided in the gear case 31, the convex portion 65 and the heat conductive sheet 61 are provided. As a result, the heat conduction efficiency between the gear case 31 and the heat conductive sheet 61 can be increased. Thereby, the heat dissipation of the brush 44 can further be improved.

  Further, in the wiper motor 11, the four fixed leg portions 43a provided on the brush holder 43 are arranged at the four corners of the tip surface 65a of the convex portion 65 partitioned by the rib portion 66. The heat conductive sheet 61 can be sandwiched between the fixed leg portion 43 a and the heat conductive sheet 61 can be reliably brought into contact with the fixed leg portion 43 a and the rib portion 66. Thereby, the heat dissipation of the brush 44 can further be improved.

  As shown in FIG. 8, the side surface 66a connected to the tip surface 65a of the convex portion 65 of each rib portion 66 is formed to be inclined with respect to the tip surface 65a. That is, the rib part 66 is formed so that the cross section becomes trapezoidal. Thereby, the clearance gap between the curved portion of the heat conductive sheet 61 crushed in the reverse direction by the rib portion 66 and the fixed leg portion 43 a and the side surface 66 a of the rib portion 66 can be reduced.

  Thus, in this wiper motor 11, since the side surface 66a connected to the front end surface 65a of the convex portion 65 of the rib portion 66 is inclined with respect to the front end surface 65a, the base portions of the heat conductive sheet 61 and the rib portion 66 are obtained. It is possible to increase the thermal conductivity between the thermal conductive sheet 61 and the convex portion 65 by reducing the gap generated between the thermal conductive sheet 61 and the convex portion 65.

  FIG. 9 is a perspective view showing fins formed on the outer surface of the motor mounting portion of the gear case.

  A plurality of fins 71 for heat dissipation are provided on the outer surface of the motor mounting portion 33 of the gear case 31. These fins 71 are formed integrally with the gear case 31 to increase the surface area of the gear case 31 in the motor mounting portion 33. Thereby, the heat dissipation in the motor attachment part 33 of the gear case 31 is improved. That is, the heat transferred from the brush 44 to the motor mounting portion 33 via the heat conductive sheet 61 can be efficiently radiated by these fins 71.

  As described above, in the wiper motor 11, since the plurality of heat radiation fins 71 are provided on the outer surface of the motor mounting portion 33 of the gear case 31, the brush transmitted to the motor mounting portion 33 via the heat conductive sheet 61. The heat of 44 can be efficiently radiated to the outside by the fins 71 to further enhance the heat dissipation of the brush 44.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the case where the present invention is applied to the wiper motor 11 used as a drive source of a vehicle wiper device is shown. However, the present invention is not limited to this, for example, as a drive source of a vehicle power window device. The present invention may be applied to an electric motor with a speed reduction mechanism and a continuous rated motor used for other purposes such as a power window motor used and a fan motor used as a drive source of a radiator cooling device.

  Moreover, in the said embodiment, although the four fixed leg parts 43a are provided in the brush holder 43, it does not restrict to this, for example, two fixed leg parts 43a are provided.

  Furthermore, in the above-described embodiment, the rib portion 66 is formed in a cross shape in accordance with the four fixed leg portions 43a. However, the shape is not limited to this, and the shape may be adjusted to the number of the fixed leg portions 43a. it can. For example, when the two fixed leg portions 43a are provided in the brush holder 43, the rib portion 66 can be formed in an H shape, an I shape, or the like.

  Furthermore, in the embodiment, the gear case 31 formed in a bathtub shape is used as the base holding member. However, the present invention is not limited to this, and covers the opening of the motor body such as a cover shape. Any shape can be used.

  Furthermore, in the said embodiment, although the brush holder 43 is used, it is not restricted to this, For example, what hold | maintains a brush, such as what hold | maintains a brush with a leaf | plate spring member, should just be used.

  Furthermore, in the said embodiment, although it is set as the structure which the other surface of the heat conductive sheet 61 contact | abuts at the front-end | tip of each fixed leg part 43a of the brush holder 43, it is not restricted to this, A heat conductive member One surface may be in contact with the gear case, and the other surface may be in contact with the brush holding member. That is, since the shape of the brush holding member and the contact position with the heat conductive sheet are not limited, a structure with good heat conductivity can be appropriately handled.

  Furthermore, in the said embodiment, although the heat conductive sheet 61 is used as a heat conductive member, it is good also as a structure which apply | coats to a brush holding member not only in this but a heat conductive member in gel form. Further, the heat conductive member is not limited to the above-described embodiment, and may be any member having electrical insulation and better than the thermal conductivity of air.

11 Wiper motor (electric motor with reduction mechanism)
DESCRIPTION OF SYMBOLS 12 Motor main body 13 Reduction gear 13a Mounting leg 14 Yoke 15 Magnet 16 Armature 17 Motor shaft 18 Bearing 21 Armature core 21a Slot 22 Armature coil 23 Commutator 23a Segment piece 31 Gear case (base fixing member)
32 Worm gear mechanism 32a Worm 32b Worm wheel 33 Motor mounting portion 33a Bottom wall 33b Through hole 34 Cover 35, 36 Screw member 37, 38 Bearing 41 Brush unit 42 Holder base 42a Guide wall portion 42b Base portion 42c Insertion hole 42d Arc-shaped portion 42e Linear part 43 Brush holder (Brush holding member)
43a Fixed leg (fixed part)
44 Brush 44a Pigtail 45 Spring 46 Power supply terminal 47 Choke coil 48 Output shaft 51 Control board 52 Lead member 53 Connector 54 Bulkhead member 61 Thermal conductive sheet (thermal conductive member)
62 Seat mounting portion 63 Holding wall 64 Fixing hole 65 Protruding portion 65a Tip surface 66 Rib portion 66a Side surface 71 Fin

Claims (16)

An electric motor having a motor shaft that is rotated by an electric current and a bottomed cylindrical motor body that supports the motor shaft,
A commutator fixed to the motor shaft;
A plurality of metal brush holding members each fixed to a holder base in a fixing part;
A plurality of brushes held by the corresponding brush holding members and in sliding contact with the commutator;
A base fixing member that covers the opening of the motor body and to which the holder base is fixed;
Wherein provided between the base fixing member and the brush holding member, it has a thermally conductive member in contact with at least a portion of the base fixing member and the brush holding member,
The holder base is provided with a holding wall that surrounds and holds the outer periphery of the heat conductive member, and the base fixing member is a protrusion that is inserted into the holding wall and contacts the heat conductive member. electric motor, wherein Rukoto provided.   2. The electric motor according to claim 1, wherein the fixing portion includes a fixing leg portion of the brush holding member, and the heat conductive member is provided between the base fixing member and the holder base. And the fixed leg portion.   3. The electric motor according to claim 1, wherein the heat conductive member is formed thicker than a gap between the base fixing member and the holder base, and the heat conductive member is compressed. And an electric motor characterized by being arranged between the holder base and the holder base.   The electric motor according to any one of claims 1 to 3, wherein the heat conductive member is formed of a heat conductive resin having an insulating property.   The electric motor according to claim 1, wherein the heat conductive member is made of an acrylic material.   The electric motor according to any one of claims 1 to 5, wherein the heat conductive member is formed of a heat conductive sheet.   The electric motor according to claim 1, wherein the heat conductive member has an insulating property and is formed by applying to at least a part of the brush holding member. Electric motor. The electric motor according to claim 1, wherein a rib portion protruding toward the holder base is provided on a tip surface of the convex portion. 9. The electric motor according to claim 8 , wherein the rib portion has a cross shape. 10. The electric motor according to claim 9 , wherein each of the brush holding members is provided with four fixed leg portions, and each of the fixed leg portions is arranged at four corners of the front end surface of the convex portion partitioned by the rib portion. An electric motor characterized by The electric motor according to any one of claims 8 to 10 , wherein a side surface of the rib portion that is continuous with a tip surface of the convex portion is inclined with respect to the tip surface. The electric motor according to any one of claims 1 to 11 , wherein a fin for heat radiation is provided on an outer surface of the base fixing member. The electric motor according to any one of claims 1 to 12 , wherein the electric motor is an electric motor with a reduction mechanism used in a vehicle. The electric motor according to any one of claims 1 to 12 , wherein the electric motor is a continuous rated motor used in a vehicle, and the base fixing member has a cover shape. The electric motor according to any one of claims 1 to 12 , wherein the electric motor is a fan motor used as a drive source of a radiator cooling device for a vehicle, and the base fixing member has a cover shape. Electric motor to do. The electric motor according to any one of claims 1 to 13 , wherein the electric motor is a wiper motor used as a driving source of a wiper device of a vehicle, and the base fixing member is a gear case that houses the holder base. An electric motor characterized by

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