JP2011223778A - Motor with deceleration mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure in which a stress is hardly loaded to a control board.SOLUTION: In a motor with a deceleration mechanism which has a metallic bottomed gear case 20 and a gear cover 23 for closing an opening side of the gear case 20 and in which a control board 34 assembled with the gear cover 23 is accommodated in the gear case 20, in the gear case 20, a projection 45 is provided which is protruded toward the control board 34 and abutted to a substrate 34a of the control board 34. A heat conductive sheet 47 is provided in a gap 46 formed between the substrate 34a of the control board 34 and a counter face 44a of a heat radiating part 44 by the projection 45. Furthermore, a seal 52 comprised of an elastic material is provided in an assembling part 51 of the gear case 20 and the gear cover 23 and by adjusting a crushing amount of the seal 52, a position of the control board 34 with respect to the gear case 20 is adjusted.

Description

  The present invention relates to a motor with a speed reduction mechanism having a control board for controlling the rotational drive of an electric motor.

  For example, as a vehicle-mounted actuator such as a wiper device or a power window device, a motor with a speed reduction mechanism that uses an electric motor and a speed reduction mechanism as one unit is used. The motor with a speed reduction mechanism has a speed reduction mechanism including a worm provided on the motor shaft of the electric motor and a worm wheel that meshes with the worm. Then, the rotation of the motor shaft is output by being decelerated by the speed reduction mechanism so as to drive the link mechanism of the wiper device which is a driven member. The motor with a speed reduction mechanism has a bottomed gear case to which the electric motor is attached and accommodates the speed reduction mechanism, and a gear cover that closes the opening side of the gear case. In such a motor with a speed reduction mechanism, a motor with a speed reduction mechanism in which a control board that outputs a drive signal to the electric motor to control the rotational drive of the electric motor is accommodated in a gear case is described in, for example, Patent Document 1. Has been.

  In this motor with a speed reduction mechanism, the gear case and the gear cover are formed of a resin material, and the control board is assembled to the gear cover. The gear cover is insert-molded with a heat sink formed of a metal material having good thermal conductivity such as aluminum, and the heat sink is disposed to face the control board. The heat sink includes a minute protrusion that protrudes toward the control board, and a predetermined gap is formed between the heat sink and the control board when the minute protrusion is abutted against the control board. A heat conductive adhesive is applied to the gap, and heat generated by the electronic components mounted on the control board is transmitted to the heat sink via the heat conductive adhesive, and heat is released from the heat sink to the outside. It is like that.

JP 2008-253049 A

  By the way, compared with metal products, resin products are less accurate and tend to have larger dimensional tolerances. For this reason, as described in Patent Document 1, when the resin-molded gear cover and the control board are assembled, the dimensions of the gear case and the board vary, and therefore the position of the board with respect to the heat sink varies. Occurs. That is, since the size of the gap formed between the heat sink and the substrate varies, it is necessary to apply the heat conductive adhesive with a margin in advance, which causes stress on the control substrate. When stress is applied to the control board in this way, problems such as shortening the life of joining electronic components mounted on the control board may occur.

  An object of the present invention is to provide a structure in which stress is not easily applied to a control board.

  The motor with a speed reduction mechanism of the present invention is provided with an electric motor that rotates and drives a motor shaft, and has a bottomed gear case that houses a speed reduction mechanism that decelerates and outputs the rotation of the motor shaft, and an opening side of the gear case. A motor with a speed reduction mechanism having a gear cover that is closed, the control board being assembled to the gear cover and housed in the gear case, and outputting a drive signal to the electric motor; provided in the gear case; A heat dissipating part for releasing the heat to be transmitted; a protrusion provided on the gear case, protruding toward the control board and abutting against the control board; and between the control board and the heat dissipating part by the protrusion. A heat transfer member that is provided in the formed gap and transmits heat generated by the control board to the heat radiating portion; the gear case; and the gear. An elastic member provided in the assembly portion of the bar, characterized by having a position adjusting means for adjusting the position of the control board in which the gear case against by adjusting the crush amount of the elastic member.

  The motor with a speed reduction mechanism according to the present invention is characterized in that the protrusion is provided adjacent to a contact position between the gear cover and the control board.

  In the motor with a speed reduction mechanism of the present invention, the gear cover is provided with a connector portion that can be connected to an external connector, and the control board and the connector portion are electrically connected to each other by terminals insert-molded in the resin gear cover. It is connected.

  According to the present invention, the protrusions that are abutted against the control board assembled to the gear cover are provided in the gear case, and the protrusions form a gap between the control board and the heat dissipation part. Can be reduced. Thereby, it becomes possible to make small the thickness dimension of the heat-transfer member provided in the said clearance gap, and can improve heat dissipation by making the thickness dimension of a heat-transfer member small. In addition, an elastic member is provided in the assembly part of the gear case and the gear cover, and the position of the control board relative to the gear case is adjusted by adjusting the amount of crushing of the elastic member, so the dimensions of the gear case, gear cover, control board, etc. Even if variations occur, a structure in which stress is not easily applied to the control board from the protrusions of the gear case can be obtained.

It is a perspective view of the wiper motor which is one embodiment of the present invention. It is sectional drawing of the wiper motor shown in FIG. It is explanatory drawing which shows the internal structure of a gear case. It is explanatory drawing which shows the state by which the control board was assembled | attached to the gear case. It is explanatory drawing which shows the assembly | attachment structure of a control board. It is explanatory drawing corresponding to FIG. 5 which shows the assembly structure of the control board as a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The wiper motor 10 is provided in a wiper device mounted on a vehicle such as an automobile, and is used to drive a link mechanism (not shown) connected to a wiper blade for wiping the window glass. The wiper motor 10 is a motor with a speed reduction mechanism in which a motor main body (electric motor) 11 and a speed reduction mechanism that decelerates the rotation of the motor main body 11 and transmits it to the link mechanism are combined into one unit. And a gear portion 12 having a speed reduction mechanism.

  A DC motor with a brush is used for the motor main body 11, and a motor shaft 13 provided in the motor main body 11 can rotate in the forward direction or the reverse direction. The motor body 11 has a yoke 14 formed by press-forming a thin steel plate or the like into a bottomed stepped cylinder. On the inner peripheral surface of the yoke 14, a plurality of permanent magnets 15 magnetized with N and S poles radially inward are alternately fixed in the rotational direction of the motor shaft 13. Thus, a magnetic field is formed inside the yoke 14.

  Inside the yoke 14, an armature 16 facing each permanent magnet 15 through a minute gap (air gap) is rotatably accommodated. The armature 16 has an armature core 16a having a plurality of slots in the rotation direction of the motor shaft 13, and a plurality of armature coils 16b are mounted on each slot of the armature core 16a by winding a conductive wire. In addition, a motor shaft 13 is fixed through the shaft center of the armature 16, and an axial base end portion of the motor shaft 13 is rotatably supported by a bearing 17 fixed to the bottom wall of the yoke 14. ing.

  A commutator 18 that rotates integrally with the armature 16 is fixed to the motor shaft 13 so as to be adjacent to the distal end side in the axial direction of the armature 16. The commutator 18 includes a plurality of segment pieces arranged at equal intervals in the rotation direction of the motor shaft 13 in a state of being insulated from each other, and the coil end of the corresponding armature coil 16b is electrically connected to each segment piece. It is connected.

  The motor body 11 is attached to the gear case 20 of the gear portion 12 on the opening side of the yoke 14. A gear case 20 formed of a metal material having good thermal conductivity such as aluminum has a substantially rectangular bottomed case portion 21 that opens in a direction orthogonal to the axial direction of the motor shaft 13 and a cylinder that opens on the yoke 14 side. The motor connection part 22 of a shape is provided. The gear case 20 is provided with a resin gear cover 23 formed in an outer shape substantially the same as that of the case portion 21, and the gear cover 23 closes the opening side of the case portion 21 of the gear case 20.

  The motor body 11 is fixed to the gear case 20 with a plurality of fastening screws in a state where the end surface on the opening side of the yoke 14 is abutted against the end surface on the opening side of the motor connection portion 22. The front end side of the motor shaft 13 in the axial direction protrudes into the case portion 21 via the motor connection portion 22 and is rotatably supported by bearings 25 and 26 fixed inside the case portion 21. A worm 13a is integrally provided on the outer peripheral surface of the motor shaft 13 between the bearings 25 and 26 on the front end side in the axial direction.

  Inside the motor connection portion 22, a resin brush holder 27 is accommodated around the commutator 18. The brush holder 27 of the motor body 11 includes a plurality of brushes 29 urged radially inward of the motor shaft 13 by spring members 28, and each brush 29 is in sliding contact with the outer peripheral surface of the commutator 18. . When a current is supplied to the armature coil 16b through the brush 29 and the commutator 18, an electromagnetic force torque is generated in the rotation direction of the armature 16 by a magnetic field formed in the yoke 14, and the motor shaft 13 is driven to rotate. It has become so.

  As shown in FIG. 3, a worm wheel 30 that meshes with the worm 13 a is rotatably accommodated inside the case portion 21. The worm wheel 30 meshes with the worm 13 a inside the case portion 21, and the rotation of the motor shaft 13 is decelerated and transmitted to the worm wheel 30 by a reduction mechanism including the worm 13 a and the worm wheel 30. ing. Further, a base end portion of an output shaft 31 that is rotated integrally with the worm wheel 30 is fixed to the shaft center of the worm wheel 30. The output shaft 31 extends in the direction opposite to the opening side of the case portion 21 and protrudes from the bottom wall portion of the case portion 21 to the outside of the gear case 20. The distal end portion of the output shaft 31 is connected to the link mechanism of the wiper device, and the link mechanism is driven by the output shaft 31.

  As shown in FIG. 2, in the case portion 21, there are a speed reduction mechanism accommodation chamber 21 a that accommodates the speed reduction mechanism, and a substrate accommodation chamber 21 b that accommodates a control board 34 for controlling the rotation drive of the motor body 11. A resin cover member 35 to be partitioned is attached. The cover member 35 of the gear case 20 has a substantially rectangular shape that covers the front end side of the motor shaft 13 in the axial direction and the worm wheel 30 from the opening side of the case portion 21, and the speed reduction mechanism accommodation chamber 21 a includes the cover member 35 and the case portion 21. It is formed between the bottom wall part. On the other hand, the substrate housing chamber 21 b is formed between the cover member 35 and the gear cover 23. The cover member 35 prevents the lubricant such as grease applied to the meshing portion between the worm 13 a and the worm wheel 30 from adhering to the control board 34.

  As shown in FIG. 4, the control board 34 is configured by mounting electronic components such as a CPU, a memory, and an FET (field effect transistor) 36 on a resin board 34a. That is, an electronic component such as an FET 36 is mounted on the end surface of the substrate 34a on the gear cover 23 side, and a circuit pattern is formed on the end surface of the substrate 34a on the gear case 20 side with a conductor such as copper foil. The control board 34 is electrically connected to each brush 29 via a power supply portion 27 a of the brush holder 27 by a power supply terminal 37 that is insert-molded in the gear cover 23. In addition, the gear cover 23 is provided with a connector portion 23a that can be connected to an external connector connected to a wiper switch, an in-vehicle battery, or the like, and the control board 34 is provided by a connector terminal 38 that is insert-molded in the gear cover 23. The gear cover 23 is electrically connected to the connector portion 23a. Thereby, the control board 34 outputs a drive signal to the motor main body 11 based on the signal from the wiper switch, and controls the rotational drive of the motor main body 11.

  In order to detect the rotation speed and rotation direction of the motor shaft 13, a pair of hall sensors 39 are provided on the control board 34, and a sensor magnet 40 is fixed to the motor shaft 13. The sensor magnet 40 is an annular multipolar magnetized magnet in which a plurality of magnetic poles are alternately magnetized in the circumferential direction. On the other hand, the pair of hall sensors 39 are arranged to face the sensor magnet 40 with a predetermined phase difference. When the motor shaft 13 rotates, a pulse signal having a period inversely proportional to the rotation speed is output from each hall sensor 39, and the control board 34 detects the rotation speed of the motor shaft 13 based on the pulse signal from the hall sensor 39. . The control board 34 detects the rotation direction of the motor shaft 13 based on the output order of the pulse signals from the hall sensors 39. These detection signals are used for controlling the rotational drive of the motor shaft 13 by the control board 34.

  Next, the assembly structure of the control board 34 will be described in detail. FIG. 5 is an explanatory view showing the assembly structure of the control board, and FIG. 6 is an explanatory view corresponding to FIG. 5 showing the assembly structure of the control board as a comparative example.

  As shown in FIG. 5, a plurality of abutting portions 23 b projecting toward the control board 34 are integrally provided on the inner surface of the gear cover 23, and the front end surface of each abutting section 23 b is the substrate of the control board 34. The gear cover 23 and the board 34 a of the control board 34 are assembled by the fastening screws 43 in a state of being abutted against the pipe 34 a. Thereby, a predetermined gap is formed between the gear cover 23 and the substrate 34a, and electronic components such as the FET 36 mounted on the substrate 34a are arranged in the gap. In addition, since the gear cover 23 and the control board 34 are assembled with the terminals 37 and 38 insert-molded in the gear cover 23 being electrically connected to the control board 34, the gear cover 23 and the control board are attached to the gear case 20. 34 can be assembled together.

  On the other hand, the case portion 21 of the gear case 20 is integrally provided with a heat radiating portion 44 that faces each of the plurality of FETs 36 mounted on the substrate 34a. Each heat radiating part 44 protrudes toward the opening side of the gear case 20 and is formed in a substantially rectangular shape corresponding to the shape of the FET 36. The end surface of the heat radiating portion 44 forms a facing surface 44a that faces the substrate 34a of the control substrate 34 at the position where the FET 36 is mounted.

  In addition, the case portion 21 of the gear case 20 is integrally provided with a plurality of protrusions 45 (not shown in FIG. 3) that protrude toward the control board 34. Each protrusion 45 is provided adjacent to the abutting position between the gear cover 23 and the substrate 34 a of the control board 34, and the tip surface of each protrusion 45 is more than the facing surface 44 a of each heat radiating part 44. It protrudes slightly on the opening side. Thus, when the control board 34 is assembled to the gear case 20 together with the gear cover 23, the front end surface of each projection 45 is abutted against the board 34 a of the control board 34 around the abutting portion 23 b of the gear cover 23, A predetermined gap (clearance) 46 is formed between 34 a and the facing surface 44 a of the heat radiating portion 44. Each protrusion 45 is abutted against the substrate 34a of the control substrate 34 at a position where it does not come into contact with a circuit pattern formed on the substrate 34a by a conductor such as copper foil.

  A thermal conductive sheet 47 made of a resin material having good thermal conductivity is provided in the gap 46. The heat conductive sheet 47 as a heat transfer member is in close contact with the end surface on the gear case 20 side of the substrate 34a at the position where the FET 36 is mounted, and in close contact with the opposing surface 44a of the heat radiating portion 44. Thereby, the heat generated in the control board 34 by energizing the FET 36 is transmitted to the heat radiating portion 44 through the heat conductive sheet 47 and is released from the heat radiating fins 48 formed in the gear case 20. .

  As shown in FIG. 6, when the projection portion 45 is not provided on the case portion 21 of the gear case 20, the dimension D of the gap 46 formed between the substrate 34 a of the control substrate 34 and the facing surface 44 a of the heat dissipation portion 44. Is determined by D = E1-E2-E3. Here, E1 is a dimension from the assembly surface 50 of the gear case 20 and the gear cover 23 to the opposing surface 44a of the heat radiating portion 44, and E2 is from the assembly surface 50 of the gear case 20 and the gear cover 23 to the substrate 34a of the control board 34. The dimension E3 is the thickness dimension of the substrate 34a of the control substrate 34. Dimensional tolerances are set for these dimensions E1 to E3. In particular, the dimensions E2 and E3 defined by the gear cover 23 and the substrate 34a formed by resin molding are the dimensions D1 defined only by the metal gear case 20. Compared to the above, the dimensional tolerance tends to be set larger. Therefore, the variation in the dimension D of the gap 46 where the heat conductive sheet 47 is provided increases.

  Therefore, in this case, when the dimension D of the gap 46 is the maximum dimension, the thermal conductive sheet 47 is surely in close contact with the substrate 34a of the control board 34 and the opposing surface 44a of the heat radiating portion 44, and the thermal conductive sheet 47. It is necessary to increase the thickness of the heat conductive sheet 47 so as to secure a sufficient amount of crushing and suppress the stress on the control board 34. However, if the thickness dimension of the thermal conductive sheet 47 is formed large, the thermal resistance increases and the thermal conductivity deteriorates, so that sufficient heat dissipation cannot be ensured.

  On the other hand, as shown in FIG. 5, when the protrusion 45 is provided on the case portion 21 of the gear case 20, the size of the gap 46 formed between the substrate 34 a of the control substrate 34 and the facing surface 44 a of the heat radiating portion 44. D is determined by D = E4. Here, E4 is a dimension from the front end surface of the protrusion 45 to the opposing surface 44a of the heat radiating part 44, and the dimension D of the gap 46 is determined only by this dimension E4. Further, the dimension E4 defined only by the metal gear case 20 tends to have a smaller dimension tolerance than the dimension defined by the gear cover 23 and the substrate 34a formed by resin molding. Therefore, the variation in the dimension D of the gap 46 where the heat conductive sheet 47 is provided can be reduced as compared to the case where the protrusion 45 is not provided as shown in FIG. Thereby, the thickness dimension of the heat conductive sheet 47 can be reduced, and heat dissipation can be improved.

  In the assembly structure of the control board 34, a sealing material 52 as an elastic member is provided in an assembly portion 51 between the gear case 20 and the gear cover 23, and the assembly surface 50 between the gear case 20 and the gear cover 23 is a sealing material. 52 is sealed. The assembling portion 51 between the gear case 20 and the gear cover 23 is provided with a convex portion 53 on the assembling surface 50 of the gear case 20 and a concave portion 54 formed on the assembling surface 50 of the gear cover 23. The convex portion 53 of the gear case 20 protrudes into the concave portion 54 of the gear cover 23, and a sealing material 52 made of an elastic material such as rubber is provided between the tip surface of the convex portion 53 and the concave portion 54. The seal material 52 is provided inside the gear case 20 with respect to the fastening screw 55 for assembling the gear case 20 and the gear cover 23. That is, the portion where the gear case 20 and the gear cover 23 are abutted with each other via the seal material 52 is disposed inside the gear case 20 with respect to the portion where the fastening force by the fastening screw 55 acts.

  Therefore, when the gear case 20 and the gear cover 23 are assembled by the fastening screw 55, the gear cover 23 is bent toward the side away from the gear case 20 with the portion where the sealing material 52 is provided as a fulcrum. The amount of bending of the gear cover 23 is adjusted by changing the tightening degree of the fastening screw 55. That is, by changing the tightening degree of the fastening screw 55 and adjusting the crushing amount of the sealing material 52 made of an elastic material, the bending amount of the gear cover 23 is changed, and the position of the control board 34 with respect to the gear case 20 can be adjusted. It can be done. This position adjusting means prevents the gear case 20 and the gear cover 23 from being assembled when the substrate 34a of the control substrate 34 is pressed against the protrusion 45 of the gear case 20 and a large stress is applied to the control substrate 34. It is possible to make it difficult to apply stress to the control board 34 from the protrusion 45. That is, the control is performed with respect to the gear case 20 at a position where the substrate 34a of the control board 34 and the protrusion 45 of the gear case 20 abut against each other and the substrate 34a of the control board 34 is not pressed against the protrusion 45 of the gear case 20. By arranging the substrate 34, it is possible to suppress stress from being applied to the control substrate 34 from the protrusion 45 of the gear case 20.

  In this way, the protrusion 45 is provided on the gear case 20 to be abutted against the substrate 34 a of the control board 34 assembled to the gear cover 23, and the protrusion 45 provides a space between the substrate 34 a of the control board 34 and the opposing surface 44 a of the heat dissipation part 44. Since the gap 46 is formed in the gap 46, the dimension D of the gap 46 is determined only by the metal gear case 20, and the variation in the dimension D of the gap 46 can be reduced. Thereby, the thickness dimension of the heat conductive sheet 47 provided in the gap 46 can be reduced, and the heat dissipation can be improved by reducing the thickness dimension of the heat conductive sheet 47.

  In addition, since the sealing member 52 made of an elastic material is provided in the assembly portion 51 of the gear case 20 and the gear cover 23, and the position of the control board 34 with respect to the gear case 20 is adjusted by adjusting the amount of crushing of the sealing material 52. Even if a large variation occurs in the dimensions of the gear cover 23 formed by resin molding or the substrate 34a of the control substrate 34, a structure in which stress is not easily applied to the control substrate 34 from the protrusion 45 of the gear case 20 can be achieved. Accordingly, it is possible to prevent problems such as a shortened bonding life of electronic components mounted on the board 34a due to stress applied to the control board 34.

  Further, since the projection 45 is provided on the gear case 20 adjacent to the abutting position between the abutting portion 23b of the gear cover 23 and the substrate 34a of the control board 34, the stress applied to the control board 34 from the projection 45 is increased. It can be relaxed on the gear cover 23 side. That is, by providing the protrusion 45 around the abutting portion 23 b of the gear cover 23, bending stress is suppressed from being applied to the control board 34 from the protrusion 45 and the gear cover 23 bends away from the gear case 20. As a result, the stress applied from the protrusion 45 to the control board 34 is relieved, and a structure in which stress is not easily applied from the protrusion 45 to the control board 34 can be obtained.

  In the above embodiment, the protrusion 45 is provided on the gear case 20 adjacent to the abutting position of the abutting portion 23b of the gear cover 23 and the substrate 34a of the control board 34. The position to be provided can be arbitrarily changed.

  Moreover, in the said embodiment, although the gear case 20 was formed with the metal material and the gear cover 23 was formed with the resin material, it is not limited to this. For example, the gear case 20 may be formed of a resin material, and the heat radiating portion 44 formed of a metal material having good thermal conductivity such as aluminum may be insert-molded in the gear case 20.

  Furthermore, in the said embodiment, although the heat conductive sheet 47 was used as a heat-transfer member, it is not limited to this, For example, you may make it use the adhesive agent etc. with good heat conductivity. In the above embodiment, the sealing material 52 made of an elastic material is used as the elastic member. However, the present invention is not limited to this, and for example, between the assembly surface 50 of the gear case 20 and the assembly surface 50 of the gear cover 23. An elastic sheet may be sandwiched between the two.

  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 motor with a speed reduction mechanism of the present invention is applied to the wiper motor 10, but may be applied to another motor with a speed reduction mechanism.

  In the above embodiment, a brushed DC motor is used as the motor body (electric motor) 11. However, another electric motor such as a brushless DC motor may be used.

10 Wiper motor (motor with reduction mechanism)
11 Motor body (electric motor)
12 Gear portion 13 Motor shaft 13a Worm 14 Yoke 15 Permanent magnet 16 Armature 16a Armature core 16b Armature coil 17 Bearing 18 Commutator 20 Gear case 21 Case portion 21a Deceleration mechanism accommodation chamber 21b Substrate accommodation chamber 22 Motor connection portion 23 Gear cover 23a Connector portion 23b Contact part 25, 26 Bearing 27 Brush holder 27a Power supply part 28 Spring member 29 Brush 30 Warm wheel 31 Output shaft 34 Control board 34a Board 35 Cover member 36 FET
37 Power supply terminal 38 Connector terminal 39 Hall sensor 40 Sensor magnet 43 Fastening screw 44 Heat radiation part 44a Opposing surface 45 Projection part 46 Gap 47 Thermal conductive sheet (heat transfer member)
48 Radiation fins 50 Assembly surface 51 Assembly part 52 Sealing material (elastic member)
53 Convex part 54 Concave part 55 Fastening screw

Claims (3)

An electric motor that rotates the motor shaft is attached, and a bottomed gear case that houses a speed reduction mechanism that decelerates and outputs the rotation of the motor shaft;
A motor with a reduction mechanism having a gear cover that closes the opening side of the gear case;
A control board assembled in the gear cover and housed in the gear case and outputting a drive signal to the electric motor;
A heat dissipating part that is provided in the gear case and emits heat transmitted from the control board;
A protrusion provided on the gear case, protruding toward the control board and abutted against the control board;
A heat transfer member provided in a gap formed between the control board and the heat radiating part by the protrusion, and transferring heat generated by the control board to the heat radiating part;
And a position adjusting means for adjusting a position of the control board with respect to the gear case by adjusting a crushing amount of the elastic member, the elastic member being provided in an assembly portion of the gear case and the gear cover. A motor with a speed reduction mechanism.   The motor with a speed reduction mechanism according to claim 1, wherein the protrusion is provided adjacent to a contact position between the gear cover and the control board.   3. The motor with a speed reduction mechanism according to claim 1 or 2, wherein the gear cover is provided with a connector portion connectable to an external connector, and the control board, the connector portion, and the like are formed by terminals insert-molded in the gear cover made of resin. Are electrically connected. A motor with a speed reduction mechanism.

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