JP2022134965A - Motor and motor with speed reducer - Google Patents

Abstract

To provide a motor and a motor with a speed reducer that can improve the mounting position accuracy of a stator in a case where two fixing portions for inserting tapping screws are provided in the stator at intervals of 180° in the circumferential direction when the stator is fixed to a case with the tapping screws.SOLUTION: A stator 8 includes a tubular core body 21, a plurality of tooth portions 22 protruding radially inward from the inner peripheral surface of the core body 21, and two fixed portions 23 provided on the outer peripheral portion of the core body. The fixing portion 23 has screw insertion holes 27 arranged at intervals of 180° in the circumferential direction and through which the tapping screws 28 are inserted. The first length L1 between the fixed seat surface 13 and the second end surface 23b of the fixing portion 23 is shorter the second length L2 between the fixed seat surface 13 and the second end surface 21b of the core body 21.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a motor and a motor with a speed reducer.

2. Description of the Related Art Conventionally, a motor is known that includes a stator that is housed in a case and has teeth around which coils are wound, and a rotor that is rotatably provided radially inside the stator in the case and has a magnet. When the coil is energized, a magnetic flux linkage is formed in the stator, and magnetic attraction and repulsion are generated between the magnetic flux linkage and the magnet, causing the rotor to rotate continuously.

Here, the stator may be fastened and fixed to the case using screws. Such a stator is provided with a fixing portion through which a screw can be axially inserted on the outer peripheral portion thereof. The stator is fastened and fixed to the case by inserting the screw through the fixing portion and tightening the screw to the case. Also, tapping screws are sometimes used to prevent loosening of the screws.

JP 2019-187132 A

However, when the tapping screw is tightened into the case as in the conventional technology described above, there is a possibility that the accuracy of screw centering will greatly affect the mounting position accuracy of the stator. That is, when the tapping screw is tightened obliquely with respect to the axial direction of the stator, the axial force of the screw acts obliquely with respect to the axial direction of the stator. In such a case, the position of the stator may deviate from the desired position.
In particular, when the motor is restricted in shape and only two fixing portions are provided on the stator at intervals of 180° in the circumferential direction, the accuracy of screw centering greatly affects the mounting position accuracy of the stator. Also, the longer the tapping screw, the more difficult it could be to center.

Accordingly, the present invention provides a stator mounting position in a case where a stator is fastened and fixed to a case by a tapping screw, and in a case where two fixing portions through which the tapping screw is inserted are provided in the stator at intervals of 180° in the circumferential direction. Provided are a motor capable of improving accuracy and a motor with a speed reducer.

In order to solve the above problems, the motor according to the present invention includes a case having a fixed seat surface, a stator housed in the case and fastened and fixed to the fixed seat surface by a tapping screw, and a rotatably provided rotor, wherein the stator includes a cylindrical core main body and a plurality of teeth protruding radially inward from an inner peripheral surface of the core main body and around which a coil is wound. and two fixed portions provided on the outer periphery of the core body portion and placed on the fixed seat surface, and the fixed portions are arranged at intervals of 180° in the circumferential direction. Also, the tapping screw has a screw insertion hole through which the tapping screw is inserted along the axial direction of the stator. The first length between the fixing bearing surfaces and the one end surface of the core opposite to the fixing bearing surfaces in the core main body is shorter than the second length between the fixed bearing surfaces.

A motor with a speed reducer according to the present invention includes the motor described above, and a reduction section coupled to the rotor for reducing rotation of the rotor and outputting the reduced speed.

According to the present invention, in the case where the stator is fastened and fixed to the motor case by the tapping screws, and in the case where the stator is provided with two fixing portions through which the tapping screws are inserted are provided at intervals of 180° in the circumferential direction, the tapping screws are fixed. Length can be as short as possible. As a result, it is possible to easily improve the centering accuracy of the tapping screw. Therefore, it is possible to improve the mounting position accuracy of the stator.

1 is a perspective view of a motor with a speed reducer according to an embodiment of the present invention; FIG. Sectional drawing which follows the II-II line of FIG. FIG. 4 is a perspective view of the motor with the second motor case removed according to the embodiment of the present invention; FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3; The perspective view of the 1st electromagnetic steel plate in embodiment of this invention. The perspective view of the 2nd electromagnetic steel plate in embodiment of this invention. Explanatory drawing which shows the assembly|attachment method of the stator to the 1st motor case in embodiment of this invention.

Next, embodiments of the present invention will be described based on the drawings.

<Motor with reducer>
FIG. 1 is a perspective view of a motor 1 with a reduction gear. FIG. 2 is a cross-sectional view along line II-II of FIG.
A motor 1 with a speed reducer is used, for example, as a drive source for a wiper device of a vehicle.
As shown in FIGS. 1 and 2 , the motor 1 with a speed reducer includes a motor 2 , a speed reducer 3 that speeds down the rotation of the motor 2 and outputs it, and a controller 4 that controls the drive of the motor 2 .
In the following description, the term "axial direction" simply means a direction parallel to the central axis of the shaft 31 of the motor 2 (rotational axis C of the motor 2). The term “circumferential direction” simply means the circumferential direction (rotational direction) of the shaft 31 . The term "radial direction" simply means the radial direction of the shaft 31 perpendicular to the axial direction and the circumferential direction.

<Motor>
The motor 2 includes a motor case 5, a substantially cylindrical stator 8 housed in the motor case 5, a rotor 9 disposed radially inside the stator 8 and rotatable with respect to the stator 8, It has The motor 2 is a so-called brushless motor that does not require brushes when supplying power to the stator 8 .

<Motor case>
The motor case 5 is made of a material such as an aluminum alloy that is excellent in heat dissipation. The motor case 5 is composed of a first motor case 6 and a second motor case 7 which are separable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a cylindrical shape with a bottom.

The bottom portion 10 of the first motor case 6 is formed integrally with the gear case 40 of the reduction portion 3 . A through hole 10 a through which the shaft 31 of the motor 2 can be inserted is formed in the center of the bottom portion 10 in the radial direction. The openings 6a and 7a of the first motor case 6 and the second motor case 7 are formed with outer flange portions 16 and 17 projecting radially outward. The outer flange portions 16 and 17 are butted against each other, and the first motor case 6 and the second motor case 7 are integrated with bolts 25 . The motor case 5 has an internal space closed by the first motor case 6 and the second motor case 7, and the stator 8 and the rotor 9 are accommodated in this internal space.

FIG. 3 is a perspective view of the motor with the second motor case 7 removed. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.
As shown in FIGS. 3 and 4, fixed seating surfaces 13 are formed at the corners of the bottom portion 10 and the peripheral wall 12 of the first motor case 6 on both sides of the through hole 10a. That is, the fixed seat surfaces 13 are arranged at intervals of 180° in the circumferential direction.

The fixed seat surface 13 protrudes from the bottom portion 10 toward the opening portion 6 a and protrudes radially inward from the inner peripheral surface of the peripheral wall 12 . An end surface 13 a of the fixed seat surface 13 on the side of the opening 6 a is a flat surface parallel to the bottom portion 10 . The stator 8 is mounted on the end face 13 a and accommodated in the motor case 5 .

<Stator>
The stator 8 includes a stator core 20 placed on the end surface 13 a of the fixed seat surface 13 and a plurality of coils 24 wound around the stator core 20 . The stator core 20 includes a cylindrical core body portion 21 , a plurality of (for example, six) teeth portions 22 protruding radially inward from the inner peripheral surface of the core body portion 21 , and the outer peripheral surface of the core body portion 21 . and two fixing portions 23 integrally molded to the .

The core body portion 21 is formed such that the position of the outer peripheral surface is substantially the same as the radially inner end of the fixed seat surface 13 or slightly inside the radially inner end of the fixed seat surface 13 . The two fixed portions 23 protrude radially outward from the outer peripheral surface of the core body portion 21 and are arranged at positions corresponding to the fixed seat surfaces 13 of the first motor case 6 . That is, the fixed portions 23 are arranged on the outer peripheral surface of the core body portion 21 at intervals of 180° in the circumferential direction. The fixing portion 23 is placed on the end surface 13 a of the fixing seat surface 13 .

A first end surface 23a of the fixed portion 23 on the side of the fixed seat surface 13 (an example of the other end surface of the fixed portion in the claims) is a first end surface of the core body portion 21 on the side of the fixed seat surface 13 (an example of the other end surface of the core in the claims). ) 21a.

Here, the first length between the first end surface 23a of the fixing portion 23 and the second end surface (an example of one end surface of the fixing portion in the claims) 23b opposite to the first end surface 23a is L1'. L2′ is the second length between the first end surface 21a of the core body 21 and the second end surface 21b opposite to the first end surface 21a (an example of the core one end surface in the claims). Then, each length L1, L2 is
L2′>L1′ (1)
meet.

In other words, the first length L1 between the fixed seat surface 13 and the second end surface 23b of the fixed portion 23 is the second length between the fixed seat surface 13 and the second end surface 21b of the core body portion 21. Shorter than L2. As a result, when the first end surface 23 a of the fixing portion 23 is placed on the end surface 13 a of the fixed seat surface 13 , the height of the fixed portion 23 from the fixed seat surface 13 is greater than the height of the core body portion 21 from the fixed seat surface 13 . height becomes lower. That is, a step is formed between the second end surface 21b of the core body portion 21 and the second end surface 23b of the fixing portion 23 .

A screw insertion hole 27 is formed through the fixing portion 23 in the axial direction. A tapping screw 28 is inserted through the screw insertion hole 27 from the side opposite to the fixed seat surface 13 . The tapping screw 28 has a shaft portion 28a and a head portion 28b integrally formed at one axial end of the shaft portion 28a.
A pilot hole 29 is formed in advance in the fixed seat surface 13 , and the stator core is attached to the first motor case 6 by tightening the threaded portion 28 c of the shaft portion 28 a of the tapping screw 28 into the pilot hole 29 . 20 is fastened and fixed.

Here, when the nominal length of the tapping screw 28 (the length of the shaft portion 28a) is represented by Ly, the nominal length Ly and the distance between the fixed bearing surface 13 and the second end surface 21b of the core main body portion 21 are the nominal length Ly. 2 The length L2 is
L2>Ly (2)
meet.

Such a stator core 20 is formed by laminating two kinds of electromagnetic steel sheets 33 and 34 (first electromagnetic steel sheet 33 and second electromagnetic steel sheet 34).

FIG. 5 is a perspective view of the first electromagnetic steel sheet 33 of the two types of electromagnetic steel sheets 33 and 34. As shown in FIG.
As shown in FIG. 5, the first electromagnetic steel plate 33 includes an annular core plate 35, a plurality of (for example, six) teeth plates 36 protruding radially inward from the inner peripheral edge of the core plate 35, and two fixing plates 37 protruding radially outward from the outer peripheral edge of the core plate 35 .
The core plate 35 constitutes the core body portion 21 . The tooth plate 36 constitutes the tooth portion 22 . The fixing plate 37 constitutes the fixing portion 23 . The fixing plate 37 is formed with a through-hole 37 a forming the screw insertion hole 27 .

FIG. 6 is a perspective view of the second electromagnetic steel sheet 34 out of the two types of electromagnetic steel sheets 33 and 34. As shown in FIG.
As shown in FIG. 6, the second electromagnetic steel plate 34 includes an annular core plate 38, a plurality of (for example, six) tooth plates 39 protruding radially inward from the inner peripheral edge of the core plate 38, have
The core plate 38 constitutes the core body portion 21 . The tooth plate 39 constitutes the tooth portion 22 .

As shown in FIGS. 2 to 4, the inner peripheral surface of the core body portion 21 and each tooth portion 22 are covered with an insulator 26 made of resin. The coil 24 is wound around the corresponding predetermined tooth portion 22 from above the insulator 26 . Each coil 24 forms a magnetic flux linkage that contributes to rotation of the rotor 9 by power supply from the controller 4 .

<Rotor>
The rotor 9 is rotatably arranged inside the stator 8 in the radial direction with a minute gap therebetween, and rotates by receiving the magnetic field of the stator 8 . The rotor 9 includes a shaft 31, a cylindrical rotor core 32 fitted and fixed to the shaft 31, a plurality of magnets (not shown) attached to the outer periphery of the rotor core 32, and a magnet cover covering the rotor core 32 from above the magnets. 32a.

The shaft 31 is formed integrally with a worm shaft 44 that constitutes the reduction section 3 . However, the worm shaft 44 is not limited to this, and the worm shaft 44 may be formed separately from the shaft 31 and connected to the end of the shaft 31 . The shaft 31 and the worm shaft 44 are rotatably supported by the gear case 40 via bearings 46 and 47 . The shaft 31 and the worm shaft 44 rotate around the rotation axis C. As shown in FIG. A ferrite magnet, for example, is used as the magnet. However, the magnet is not limited to this, and a neodymium bond magnet, a neodymium sintered magnet, or the like can be applied as the magnet.

<Deceleration part>
The reduction section 3 includes a gear case 40 integrated with the motor case 5 and a worm reduction mechanism 41 housed in the gear case 40 . The gear case 40 is made of a metal material such as an aluminum alloy having excellent heat dissipation properties. The gear case 40 is formed in a box shape having an opening 40a on one side. The gear case 40 has a gear accommodating portion 42 that accommodates the worm reduction mechanism 41 therein. Further, in the side wall 40b of the gear case 40, an opening 43 is formed at a portion where the first motor case 6 is integrally formed to communicate the through hole 10a of the first motor case 6 and the gear housing portion 42. .

A substantially cylindrical bearing boss 49 protrudes from the bottom wall 40 c of the gear case 40 . The bearing boss 49 is for rotatably supporting the output shaft 48 of the worm speed reduction mechanism 41, and a slide bearing (not shown) is arranged on the inner peripheral side. An O-ring (not shown) is attached to the inner peripheral surface of the tip of the bearing boss 49 . A plurality of ribs 52 are protruded from the outer peripheral surface of the bearing boss 49 to ensure rigidity.

The worm reduction mechanism 41 housed in the gear housing portion 42 is composed of a worm shaft 44 formed integrally with the shaft 31 of the rotor 9 and a worm wheel 45 meshing with the worm shaft 44 . The worm shaft 44 is rotatably supported by the gear case 40 via bearings 46 and 47 at both ends in the axial direction. An output shaft 48 of the motor 2 is provided coaxially and integrally with the worm wheel 45 . The worm wheel 45 and the output shaft 48 are arranged such that their rotation axes are perpendicular to the rotation axis C of the worm shaft 44 (the shaft 31 of the motor 2). The output shaft 48 protrudes outside through a bearing boss 49 of the gear case 40 . A projecting tip of the output shaft 48 is formed with a spline 48a that can be connected to an article to be driven by the motor.

The worm wheel 45 is also provided with a sensor magnet (not shown). The position of this sensor magnet is detected by a later-described magnetic detection element 61 provided in the controller 4 . That is, the rotational position of the worm wheel 45 is detected by the magnetic detection element 61 of the controller 4 .

<Controller>
The controller 4 has a controller board 62 on which a magnetic detection element 61 is mounted. The controller board 62 is arranged in the opening 40 a of the gear case 40 so that the magnetic detection element 61 faces the sensor magnet of the worm wheel 45 . The opening 40 a of the gear case 40 is closed by a cover 63 .

Terminals of a plurality of coils 24 drawn out from the stator core 20 are connected to the controller board 62 . Terminals of the connector 11 (see FIG. 1) provided on the cover 63 are electrically connected to the controller board 62 . The controller board 62 includes, in addition to the magnetic detection element 61, an FET (field) for controlling the drive voltage supplied to the coil 24.
A power module (not shown) composed of switching elements such as an effect transistor (field effect transistor), a capacitor (not shown) for smoothing voltage, and the like are mounted.

<How to assemble the stator>
Next, a method of assembling the stator 8 to the first motor case 6 will be described with reference to FIGS. 4 and 7. FIG.
7A and 7B are explanatory diagrams showing a method of assembling the stator 8 to the first motor case 6. FIG. FIG. 7 corresponds to FIG.
As shown in FIG. 7, an insulator 26 is attached to the stator core 20 in advance, and the coil 24 is wound on the insulator 26 . In this state, the first end surface 23a side of the fixing portion 23 provided on the stator core 20 is placed on the end surface 13a of the fixed seat surface 13 in the first motor case 6 . At this time, the positions of the pilot holes 29 of the fixing seat surface 13 and the positions of the screw insertion holes 27 of the fixing portion 23 are aligned.

Next, the tapping screw 28 is inserted into the screw insertion hole 27 of the fixing portion 23 from the second end surface 23b side of the fixing portion 23 . Here, the first length L1′ between the first end surface 23a and the second end surface 23b of the fixing portion 23, and the second length between the first end surface 21a and the second end surface 21b of the core body portion 21 The height L2' satisfies the above formula (1). That is, when the first end surface 23 a of the fixing portion 23 is placed on the end surface 13 a of the fixed seat surface 13 , the height of the fixed portion 23 from the fixed seat surface 13 is greater than the height of the core body portion 21 from the fixed seat surface 13 . height is reduced. Since the nominal length Ly of the tapping screw 28 can be shortened accordingly, the tapping screw 28 can be accurately centered.

In addition, the nominal length Ly of the tapping screw 28 and the second length L2 between the fixed seat surface 13 and the second end surface 21b of the core body portion 21 satisfy the above formula (2). Therefore, when the tapping screw 28 is inserted from the second end surface 23 b side of the fixing portion 23 into the screw insertion hole 27 of the fixing portion 23 , the tip of the shaft portion 28 a of the tapping screw 28 reaches the fixing seat surface 13 . First, the head portion 28b of the tapping screw 28 is positioned closer to the fixed seat surface 13 (lower side in FIG. 7) than the second end surface 21b of the core body portion 21 is. That is, when the tapping screw 28 is tightened into the pilot hole 29 of the fixed seat surface 13 , the tapping screw 28 is tightened while the head 28 b of the tapping screw 28 is along the outer peripheral surface of the core body 21 . In other words, since the steps are formed on the second end faces 23b, 21b of the stator core 20, the side surfaces of the steps (the outer peripheral surface of the core main body 21) guide the head 28b of the tapping screw 28. As shown in FIG. As a result, the tapping screw 28 can be centered more accurately.

After that, by completely tightening the tapping screw 28, the assembly of the stator 8 to the first motor case 6 is completed (see FIG. 4).

Thus, in the above-described embodiment, the stator 8 (stator core 20) is fastened and fixed to the motor case 5 (first motor case 6) by the tapping screw 28, and the tapping screw 28 is inserted through the stator 8. When two portions 23 are provided at intervals of 180° in the circumferential direction, the first length L1 between the fixed seat surface 13 and the second end surface 23b of the fixed portion 23 is equal to the fixed seat surface 13 and the core body portion. 21 is shorter than the second length L2 between the second end face 21b. Therefore, the nominal length Ly of the tapping screw 28 can be made as short as possible. Since the longer the nominal length Ly, the more difficult it is to center the tapping screw 28, the shorter the nominal length Ly, the easier it is to improve the centering accuracy of the tapping screw 28. Therefore, the mounting position accuracy of the stator 8 can be improved.

When the nominal length Ly of the tapping screw 28 is shortened, the diameter of the screw insertion hole 27 of the fixing portion 23 can be made as small as possible. Therefore, the stator 8 can be miniaturized.
In addition, since it is not necessary to form the fixing portion 23 over the entire axial direction of the stator core 20, the manufacturing cost can be reduced. As a result, it will be possible to contribute to Goal 12 of the Sustainable Development Goals (SDGs) led by the United Nations, "Ensure sustainable consumption and production patterns."

In stator core 20, first end surface 23a of fixed portion 23 and first end surface 21a of core body portion 21 are positioned on the same plane. Therefore, when forming the stator core 20, the stator core 20 can be formed simply by collectively laminating one of the two electromagnetic steel plates 33 and 34 and subsequently collectively laminating the other. Therefore, the nominal length Ly of the tapping screw 28 can be shortened while the stator core 20 is easily formed.

Moreover, by forming the first end surfaces 23a and 21a of the stator core 20 on the same plane as the fixed seat surface 13 side, it is possible to prevent the stator core 20 from interfering with the fixed seat surface 13 due to manufacturing errors of the stator core 20. . Further, since the steps can be formed on the second end surfaces 23b, 21b of the stator core 20, the head 28b of the tapping screw 28 can be easily guided.

In addition, the nominal length Ly of the tapping screw 28 and the second length L2 between the fixed seat surface 13 and the second end surface 21b of the core body portion 21 satisfy the above formula (2). Therefore, when the tapping screw 28 is inserted from the second end surface 23 b side of the fixing portion 23 into the screw insertion hole 27 of the fixing portion 23 , the tip of the shaft portion 28 a of the tapping screw 28 reaches the fixing seat surface 13 . First, the head portion 28b of the tapping screw 28 is reliably positioned closer to the fixed seat surface 13 than the second end surface 21b of the core body portion 21 is. As a result, when the tapping screw 28 is screwed into the pilot hole 29 of the first motor case 6, the side surface of the step on the second end surfaces 23b, 21b side of the stator core 20 (the outer peripheral surface of the core main body 21) is the head of the tapping screw 28. It guides the portion 28b. Therefore, the tapping screw 28 can be easily centered, and the mounting position accuracy of the stator 8 can be further improved.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications of the above-described embodiments within the scope of the present invention.
For example, in the above-described embodiment, the case where the motor 1 with a speed reducer is used as a drive source for a wiper device of a vehicle, for example, has been described. However, it is not limited to this, and the motor 1 with a speed reducer can be applied as various driving devices. In addition, among the motors 1 with reduction gears, only the motors 2 having the above configuration may be employed in various electric devices.

In the above-described embodiment, the stator core 20 has been described in which the first end surface 23a of the fixed portion 23 and the first end surface 21a of the core body portion 21 are positioned on the same plane. However, it is not limited to this, and a step may be formed between the first end surface 23 a of the fixed portion 23 and the first end surface 21 a of the core body portion 21 . A first length L1 between the fixed seat surface 13 and the second end surface 23b of the fixed portion 23 is shorter than a second length L2 between the fixed seat surface 13 and the second end surface 21b of the core body portion 21. Just do it.

In the above embodiment, the nominal length Ly of the tapping screw 28 and the second length L2 between the fixed seat surface 13 and the second end surface 21b of the core body 21 satisfy the above formula (2). did. However, it is not limited to this. The axial direction of the fixing portion 23 may be shortened, and the nominal length Ly of the tapping screw 28 may be shortened accordingly.

In the above-described embodiment, the stator core 20 is formed by laminating two types of electromagnetic steel sheets 33 and 34 (the first electromagnetic steel sheet 33 and the second electromagnetic steel sheet 34). However, it is not limited to this, and the stator core 20 may be formed by pressure-molding soft magnetic powder.

In the above-described embodiment, the case where the two fixing portions 23 protrude radially outward from the outer peripheral surface of the core body portion 21 of the stator core 20 has been described. However, it is not limited to this, as long as the fixing portion 23 is provided on the outer peripheral portion of the core body portion 21 . That is, for example, a screw insertion hole 27 through which the shaft portion 28a of the tapping screw 28 can be inserted is formed in the outer peripheral portion of the core body portion 21, and the head portion 28b of the tapping screw 28 is formed in the second end face 21b of the core body portion 21. It is also possible to perform counterbore processing to allow storage, and configure the portion where the counterbore processing is performed and the screw insertion hole 27 as the fixing portion 23 . In this case, the bottom surface of the countersinked portion (the portion where the head portion 28b of the tapping screw 28 is accommodated) becomes the second end surface 23b of the fixing portion 23 .

DESCRIPTION OF SYMBOLS 1... Motor with a reduction gear, 2... Motor, 3... Reduction part, 4... Controller, 5... Motor case (case), 6... First motor case (case), 6a, 7a... Opening, 7... Second motor Case 8 Stator 9 Rotor 10 Bottom 10a Through hole 11 Connector 12 Peripheral wall 13 Fixed bearing surface 13a End surface 16, 17 Outer flange 20 Stator core 21 ... Core main body part 21a ... First end face (core other end face) 21b ... Second end face (core one end face) 22 ... Teeth part 23 ... Fixed part 23a ... First end face (fixed part other end face) 23b Second end surface (one end surface of fixed portion) 24 Coil 25 Bolt 26 Insulator 27 Insertion hole 28 Tapping screw 28a Shaft 28b Head 28c Threaded portion 29 Pilot hole 31 Shaft 32 Rotor core 32a Magnet cover 33 First electromagnetic steel sheet 34 Second electromagnetic steel sheet 35, 38 Core plate 36, 39 Teeth plate 37 Fixed plate 37a Through hole 40 Gear case 40a Opening 40b Side wall 40c Bottom wall 41 Worm reduction mechanism 42 Gear housing 43 Opening 44 Worm shaft 45 Worm wheel 46, 47... Bearing, 48... Output shaft, 48a... Spline, 49... Bearing boss, 52... Rib, 61... Magnetic detection element, 62... Controller board, 63... Cover, L1, L2... Length, Ly... Nominal length difference

Claims (4)

a case having a fixed seating surface;
a stator housed in the case and fastened and fixed to the fixed seat surface by a tapping screw;
a rotor rotatably provided with respect to the stator;
with
The stator is
a cylindrical core body;
a plurality of tooth portions protruding radially inward from the inner peripheral surface of the core body portion and around which a coil is wound;
two fixing parts provided on the outer peripheral part of the core main body part and placed on the fixing seat surface;
has
The fixing portion has a screw insertion hole arranged at intervals of 180° in the circumferential direction and through which the tapping screw is inserted along the axial direction of the stator,
A first length between the fixed seat surface and one end surface of the fixed portion opposite to the fixed seat surface is equal to the fixed seat surface and the fixed seat surface of the core main body. is shorter than a second length between one end face of the core on the opposite side. 2. The fixing portion other end surface of the fixed portion on the fixed seat surface side and the core other end surface of the core body portion on the fixed seat surface side are positioned on the same plane. motor as described. Let Ly be the nominal length of the tapping screw,
When the second length is L2,
L2 > Ly
3. The motor according to claim 1 or 2, wherein: a motor according to any one of claims 1 to 3;
a deceleration unit coupled to the rotor for decelerating and outputting rotation of the rotor;
A motor with a reduction gear, comprising:

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