JP7236957B2 - motor - Google Patents

Description

The present invention relates to motors.

2. Description of the Related Art As a motor, a so-called inner rotor type brushless motor is known which has a stator wound with windings and a rotor rotatably provided radially inward of the stator. A rotor of this type of motor has, for example, a rotor core having a plurality of salient poles spaced apart in the circumferential direction of the rotating shaft. Magnets are arranged so that magnetic poles of opposite polarities are alternately arranged between adjacent salient poles in the circumferential direction of the outer peripheral portion of the rotor. The outer peripheral surface of the magnet is covered with a magnet cover.

On the other hand, the stator includes a substantially cylindrical stator core, a plurality of teeth projecting radially inward from the stator core, and windings wound around the teeth.
When electric power is supplied to the windings of the motor, a predetermined magnetic field is formed in the stator. rotates continuously.

WO2019/017161

By the way, in a structure in which the outer peripheral surface of the magnet is covered with a magnet cover like a conventional rotor, the outer diameter of the magnet cover is the outermost diameter of the rotor. Therefore, it has been difficult to suppress the air gear-up between the salient poles of the rotor core and the stator. In particular, in the case of a magnetic circuit that also uses reluctance torque, the smaller the air gearup between the salient poles and the stator, the better the motor characteristics (motor torque). Therefore, it is desirable to make the air gear up as small as possible.

Accordingly, the present invention provides a motor characteristic capable of reducing the air gearup between the salient poles and the stator and increasing the motor torque (motor characteristic).

In order to solve the above problems, a motor according to the present invention includes an annular stator having a plurality of teeth, coils wound around the teeth, and a rotor rotating around the axis with respect to the stator. The rotor includes a rotating shaft that rotates about the axis, and is supported so as to rotate integrally with the rotating shaft, and is perpendicular to the axial direction and the rotating direction at intervals in the rotating direction of the rotating shaft. a rotor core having a plurality of salient poles protruding radially outward; a plurality of magnets disposed between the salient poles adjacent to each other in the rotation direction of the rotating shaft on an outer peripheral portion of the rotor core; a magnet cover that covers the outer peripheral surface of the magnet, the magnet cover having slits along the axial direction so that at least all of the outer ends of the salient poles that face the stator in the radial direction are exposed. It is characterized by having a formed guide portion.

In the above configuration, the salient pole may have an outer diameter dimension of an imaginary circle passing through the outermost end in the radial direction of the outer end of the salient pole and larger than the inner diameter dimension of the inner diameter surface of the magnet cover.

In the above configuration, the length of the guide portion in the axial direction is smaller than the length of the magnet cover in the axial direction so that the guide portion is arranged between both ends of the magnet cover in the axial direction. good too.

In the above configuration, the length of the salient pole in the axial direction is smaller than the length of the guide portion in the axial direction so that the salient pole is arranged between both ends of the guide portion in the axial direction. may

In the above configuration, the guide portion may have an opening that is formed at one end of both ends of the magnet cover in the axial direction and allows the outer ends of the salient poles to pass therethrough.

According to the present invention, since the magnet cover has the guide portion, the air gear-up between the salient poles and the stator can be reduced, and the motor characteristics can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the external appearance of the motor with a reduction gear in 1st Embodiment which concerns on this invention. Sectional drawing which shows the motor with a reduction gear in 1st Embodiment. The perspective view which shows the rotor in 1st Embodiment. FIG. 3 is an exploded perspective view showing the rotor in the first embodiment; FIG. 4 is a cross-sectional view taken along line VV of FIG. 3; The side view of the rotor in 1st Embodiment. Sectional drawing which expanded the VII part of FIG. The perspective view which shows the rotor in 2nd Embodiment which concerns on this invention.

Next, motors according to embodiments of the present invention will be described with reference to the drawings. In addition, although the motor 1 with a reduction gear is described as an example of the motor in the embodiment, it may be applied to other motors.

[First embodiment]
<Motor with reducer>
FIG. 1 is a perspective view showing the appearance of a motor 1 with a speed reducer according to a first embodiment of the present invention.
As shown in FIG. 1, a motor 1 with a speed reducer serves as a drive source for electrical components mounted on a vehicle (for example, wipers, power windows, sunroofs, electric seats, etc.). Specifically, the motor 1 with a speed reducer includes a housing 10 forming an outer shell of the motor 1 with a speed reducer, a motor section 20 provided in the housing 10, and a motor section 20 provided in the housing 10 to rotate the motor section 20. and a speed reducer unit 30 that reduces the speed and outputs the speed.

FIG. 2 is a cross-sectional view showing the motor 1 with a speed reducer.
As shown in FIGS. 1 and 2, the housing 10 is made of a material having excellent heat dissipation properties, such as die-cast aluminum. The housing 10 is composed of a housing body 11 that holds the motor section 20 and the speed reducer section 30 and a cover 12 .

A speed reducer housing portion 13 for housing a speed reducer portion 30 is formed on one surface side of the housing body 11 . The speed reducer accommodating portion 13 has a bottomed shape recessed from the top surface portion 11t of the housing body 11 toward the back surface portion 11b facing the top surface portion 11t. The speed reducer accommodating portion 13 is surrounded by a bottom portion 13b formed on the back surface portion 11b side and a peripheral wall portion 13w rising from the outer peripheral portion of the bottom portion 13b to the top surface portion 11t side.

A shaft housing groove 14 for housing a worm shaft 31 and a wheel housing recess 15 for housing a worm wheel 32 are formed in the speed reducer housing portion 13 .
Bearing portions 16A and 16B for rotatably supporting the worm shaft 31 (rotating shaft 27) are formed at both ends of the shaft receiving groove 14 in the axial direction in the reduction gear housing portion 13. As shown in FIG.

A motor accommodating portion 17 is integrally formed on the outer peripheral portion of the housing body 11 so as to extend outwardly along the axial direction of the worm shaft 31 from the peripheral wall portion 13w. The motor housing portion 17 houses a portion of the motor portion 20 . Inside the motor accommodating portion 17, a shaft insertion hole (not shown) is formed which penetrates the peripheral wall portion 13w and communicates with the bearing portion 16A.
Further, the housing body 11 is integrally formed with a boss portion 19 projecting from the back surface portion 11b to the side opposite to the top surface portion 11t. A through hole (not shown) communicating with the wheel housing recess 15 is formed through the boss 19 .

A cover 12 is provided on the top surface portion 11t side of the housing body 11 so as to close the speed reducer accommodating portion 13 . The cover 12 is fastened to the housing body 11 with bolts (not shown) at a plurality of locations on its outer periphery. A connector receiving portion 12 c is formed in the cover 12 adjacent to the motor receiving portion 17 when the cover 12 is attached to the housing body 11 . The connector receiving portion 12c has a cylindrical shape and is connected to an external power supply connector.

<Motor part>
The motor unit 20 includes a motor cover 21 attached to the motor housing portion 17 , a cylindrical stator 22 housed in the motor housing portion 17 and the motor cover 21 , and provided radially inside the stator 22 . and a rotor 23 provided rotatably with respect to the rotor. In the following description, the direction parallel to the rotation axis of the rotor 23 (rotating shaft 27 described later) is simply referred to as the axial direction, and the rotation direction of the rotor 23 is referred to as the circumferential direction. The radial direction is the radial direction of the rotor 23 orthogonal to the axial direction and the circumferential direction.

The motor cover 21 is a member made of metal such as iron, and is formed into a cylindrical shape with a bottom by, for example, press working by deep drawing. An open end of the motor cover 21 is formed with a flange 21a (see also FIG. 1) projecting radially outward. The motor cover 21 is connected to the motor accommodating portion 17 by bolts 21b inserted through the flange 21a.

The stator 22 is arranged along the inner peripheral surface of the motor cover 21 . The stator 22 includes a substantially cylindrical stator core 24 , a plurality of teeth 25 protruding radially inward from the stator core 24 , and windings (coils) 26 wound around the stator core 24 .
Stator core 24 is formed by laminating a plurality of steel plates 24p. Note that the stator core 24 is not limited to being formed by laminating a plurality of metal plates, and may be formed, for example, by pressing soft magnetic powder. The outer peripheral surface of stator core 24 formed in this manner is fitted to the inner peripheral surface of motor cover 21 .

The teeth 25 are formed along the radially inner side of the stator core 24 at regular intervals in the circumferential direction. Windings 26 are wound around the teeth 25 . The windings 26 generate magnetic flux for rotating the rotor 23 by current supplied from a controller board (not shown).

FIG. 3 is a perspective view of the rotor 23. FIG. 4 is an exploded perspective view of the rotor 23. FIG.
As shown in FIGS. 2 to 4 , the rotor 23 has a rotating shaft 27 and a rotor body 28 fitted and fixed to the rotating shaft 27 . The rotor body 28 includes a rotor core 42, magnets (also referred to as "rotor magnets") 43A and 43B, first and second magnet holders 44A and 44B that support the magnets 43A and 43B, and magnets that cover the magnets 43A and 43B. a cover 45;
The first and second magnet holders 44A and 44B are arranged so as to sandwich the magnets 43A and 43B in the axial direction. Thereby, the first and second magnet holders 44A and 44B prevent the magnets 43A and 43B from falling off from the rotor core 42 in the axial direction.

<Rotor core>
The rotating shaft 27 is formed integrally with a worm shaft 31 that constitutes the speed reducer portion 30 . A rotor core 42 is supported by an end (one end) 27b of the rotating shaft 27 on the side of the end surface 27a. The rotor core 42 is press-fitted to the outer periphery of the rotating shaft 27 and rotates together with the rotating shaft 27 . The rotor core 42 is formed by laminating a plurality of steel plates 42p in the axial direction. It should be noted that the rotor core 42 is not limited to being formed by laminating a plurality of steel plates 42p in the axial direction, and may be formed by pressing soft magnetic powder, for example.

The rotor core 42 has a cylindrical core base end portion 47 and a plurality of salient core poles (salient poles) 48 radially projecting from the core base end portion 47 radially outward. A through hole 47a is formed in the center of the core base end portion 47 in the radial direction so as to extend therethrough in the axial direction. The rotary shaft 27 is press-fitted into the through hole 47a (see also FIG. 5). Alternatively, the rotary shaft 27 may be inserted into the through hole 47a, and the rotor core 42 may be externally fixed to the rotary shaft 27 using an adhesive or the like. The plurality of salient core poles 48 are, for example, four protruding at equal intervals of 90° in the circumferential direction.

<Magnet>
FIG. 5 is a cross-sectional view along line VV of FIG.
As shown in FIGS. 4 and 5, magnets 43A and 43B are arranged between core salient poles 48 adjacent in the circumferential direction. The magnets 43A and 43B are segment-shaped magnets having fan-shaped cross sections in the axial direction. The four magnets 43A and 43B are arranged in an annular shape on the outer peripheral surface (peripheral portion) 47b of the core base end portion 47 in the circumferential direction. The magnets 43A and 43B are made of ferrite magnets, for example. Here, since there are four magnets 43A and 43B, each of them is formed in a fan shape with a central angle θ<90°.

The magnets 43A and 43B are magnetized from an inner diameter surface (inner peripheral surface) 43c formed of an arc surface toward an outer diameter surface (outer peripheral surface) 43d. The magnets 43A and 43B are set so that when they are annularly arranged on the outer peripheral surface of the rotor core 42, the magnetic poles of the outer diameter surface 43d are alternately arranged in the circumferential direction with opposite polarities. That is, two types of magnets 43A and 43B magnetized with opposite polarities are prepared and arranged alternately along the circumferential direction on the outer peripheral surface 47b of the core base end portion 47. As shown in FIG. Accordingly, the rotor body 28 including the assembly of magnets 43A and 43B has four magnetic poles.

The magnets 43A and 43B have an inner diameter surface 43c and an outer diameter surface 43d formed as circular arc surfaces. The inner diameter surface 43c is formed, for example, as an arcuate surface concentric with the axial center of the rotor 23 (the center of the rotating shaft 27). The outer diameter surface 43d is formed, for example, as an arcuate surface centered at a radially outer offset position with respect to the center of the rotating shaft 27. As shown in FIG. Therefore, in the magnets 43A and 43B, the thickness in the radial direction between the inner diameter surface 43c and the outer diameter surface 43d is the maximum at the circumferential midpoint 43e of the outer diameter surface 43d. That is, in the magnets 43A and 43B, the midpoint 43e, which is the thickest portion, is the outermost position in the radial direction.

When the magnets 43A and 43B are arranged between the salient core poles 48 adjacent in the circumferential direction, the circumferential end faces 43t of the magnets 43A and 43B abut against the salient core poles 48 adjacent to each other. As a result, positional deviation of the magnets 43A and 43B with respect to the rotational direction of the rotor 23 can be prevented.

<Magnet holder>
As shown in FIGS. 2 to 4, the first and second magnet holders 44A and 44B each include an annular magnet holding portion 44c and a core holding portion 44d integrally formed with the magnet holding portion 44c. there is The material of the first and second magnet holders 44A and 44B is, for example, a resin material.
The magnet holding portion 44c is formed in a flat annular shape by forming an opening edge 44e in the center in the radial direction and an outer peripheral edge 44f in an arc shape. A core holding portion 44d is integrally formed on the back surface of the magnet holding portion 44c. The core holding portion 44d has an annular portion 44g and a plurality of projecting portions 44h extending radially outward from the annular portion 44g.

The annular portion 44g is formed in an annular shape along the opening edge 44e on the back surface of the magnet holding portion 44c.
The plurality of projecting portions 44h radially extend radially outward from the annular portion 44g to the outer peripheral edge 44f along the back surface of the magnet holding portion 44c. The plurality of projecting portions 44h are, for example, four projecting at equal intervals of 90° in the circumferential direction.

The end surface of the core proximal end portion 47 of the rotor core 42 is brought into contact with the annular portion 44g. End faces of core salient poles 48 of the rotor core 42 are brought into contact with the projections 44h. Specifically, the first magnet holder 44A is in contact with the core end face 42a on the opposite side of the end face 27a of the rotary shaft 27 among the core end faces 42a and 42b on both sides of the rotor core 42. As shown in FIG. The second magnet holder 44B is in contact with the core end face 42b on the side of the end face 27a of the rotary shaft 27 among the core end faces 42a and 42b on both sides of the rotor core 42. As shown in FIG.

That is, the first magnet holder 44A and the second magnet holder 44B are arranged on both core end surfaces 42a and 42b of the rotor core 42 so as to sandwich the rotor core 42 in the axial direction. Magnets 43A and 43B are arranged between the first magnet holder 44A and the second magnet holder 44B. Therefore, the magnets 43A and 43B are axially held by the first and second magnet holders 44A and 44B.

<Magnet cover>
FIG. 6 is a side view of the rotor 23. FIG.
As shown in FIGS. 4 to 6, the outer diameter surfaces 43d of the first magnet holder 44A, the second magnet holder 44B, the rotor core 42, and the magnets 43A and 43B are covered with a magnet cover 45. FIG. Furthermore, the first and second magnet holders 44A and 44B are held by a magnet cover 45. As shown in FIG. The material of the magnet cover 45 is, for example, a non-magnetic material.

The magnet cover 45 has a cylindrical portion 45a covering the outer diameter surfaces 43d of the magnets 43A and 43B, first flanges 45b and second flanges 45c arranged at both ends of the cylindrical portion 45a in the axial direction. The cylindrical portion 45a is formed in a hollow cylindrical shape. The cylindrical portion 45a is in contact with the outer diameter surfaces 43d of the magnets 43A and 43B (specifically, the midpoint 43e of the outer diameter surfaces 43d). As a result, the magnets 43A and 43B are held (fixed) by the cylindrical portion 45a in a state in which the end faces 43t of the magnets 43A and 43B are in contact (close contact) with the core salient poles 48 of the rotor core .

The cylindrical portion 45 a has a plurality of guide portions 50 . The guide portion 50 has a slit 51 formed in a portion of the cylindrical portion 45 a that faces the outer end 48 a that is the radially outer end portion of the core salient pole 48 . Outer ends 48a of the salient core poles 48 are arranged at positions facing the inner peripheral surface 22a (see FIG. 2) of the stator 22 in the radial direction. The guide portion 50 is formed continuously along the axial direction between one end 45 d and the other end 45 e of the magnet cover 45 .

The first axial dimension L1 of the guiding portion 50 is formed to be smaller than the second axial dimension L2 of the magnet cover 45 so that the guiding portion 50 is arranged between both ends 45d and 45e of the magnet cover 45 in the axial direction. ing.
Further, the salient core pole 48 is formed so that the salient core pole 48 is arranged between both ends of the slit of the guide portion 50 in the axial direction so that the third axial dimension L3 of the salient core pole 48 is smaller than the first axial dimension L1. .

Specifically, the guide portion 50 has a first slit end (one end of both ends of the guide portion 50) 50a arranged near one end 45d of the cylindrical portion 45a (lower side in FIGS. 4 and 6), and a second slit end 50a. A slit end (the other end of the two ends of the guide portion 50) 50b is arranged near the other end 45e of the cylindrical portion 45a (upward in FIGS. 4 and 6). The first slit end 50a is located at a portion closer to one end 45d than the outer end 48a of the core salient pole 48 in the projecting portion 44h of the first magnet holder 44A. The second slit end 50b is positioned closer to the other end 45e than the outer end 48a of the core salient pole 48 in the projecting portion 44h of the second magnet holder 44B.

FIG. 7 is a cross-sectional view enlarging the VII section of FIG.
As shown in FIGS. 6 and 7, the guide portion 50 has a slit width W1 in the circumferential direction larger than a salient pole width W2 in the circumferential direction of the outer end 48a of the core salient pole 48. As shown in FIGS.
That is, the projecting portion 44h of the first magnet holder 44A is exposed to the outside of the magnet cover 45 from the first slit end 50a side of the guide portion 50. As shown in FIG. Also, the projecting portion 44h of the second magnet holder 44B is exposed to the outside of the magnet cover 45 from the second slit end 50b side of the guide portion 50 . Further, the entire outer end 48 a of the salient core pole 48 is exposed outside the magnet cover 45 from the central portion of the guide portion 50 .
As another example of the guide portion 50, only the entire outer end 48a of the core salient pole 48 is exposed, and the projecting portion 44h of each of the first magnet holder 44A and the second magnet holder 44B is exposed to the outside. You may form the guide part 50 so that it may not be made.

As described above, the magnet cover 45 has the guide portion 50 , and the slit 51 is formed as the guide portion 50 so as to extend in the axial direction of the rotating shaft 27 . The entire outer end 48a of the core salient pole 48 is exposed from the guide portion 50 to the outside. Therefore, the magnet cover 45 that restricts the radially outward protrusion of the salient core poles 48 can be removed from between the salient core poles 48 and the inner peripheral surface 22a of the stator 22 (see FIG. 2). Therefore, the air gear-up between the outer ends 48a of the core salient poles 48 and the inner peripheral surface 22a of the stator 22 can be suppressed, and the motor torque (motor characteristics) can be increased.

Further, by arranging the guide portion 50 between both ends 45d and 45e of the magnet cover 45, both ends 45d and 45e of the magnet cover 45 can be formed into a ring shape. Therefore, for example, when the rotor 23 rotates, one end 45d of the magnet cover 45 can be held by the first magnet holder 44A, and the other end 45e of the magnet cover 45 can be held by the second magnet holder 44B. Therefore, the magnet cover 45 (in particular, the cylindrical portion 45a) can reliably hold the magnets 43A and 43B.

Further, by forming the slit 51 as the guide portion 50 in the magnet cover 45, the outer end 48a of the salient core pole 48 can be arranged inside the guide portion 50 in the axial direction. That is, the outer end 48 a of the core salient pole 48 is arranged between both ends of the first slit end 50 a and the second slit end 50 b of the guide portion 50 . As a result, the entire outer end 48a of the salient core pole 48 can be reliably exposed from the guide portion 50, and the motor torque can be increased.

Here, the outer diameter dimension (radius, hereinafter simply referred to as the outer diameter dimension) of an imaginary circle C passing through the radially outermost side of the outer end 48a of the core salient pole 48 is defined as R1, and the magnet cover 45 (specifically, When the inner diameter dimension (radius) of the cover inner diameter surface 45f of the cylindrical portion 45a) is R2, the outer diameter dimension R1 is larger than the inner diameter dimension R2 of the cover inner diameter surface 45f. That is, the inner diameter dimension R2<the outer diameter dimension R1 is set. In other words, the outer ends 48a of the salient core poles 48 protrude radially outward beyond the outer diameter dimension R1 of the midpoint 43e of the magnets 43A and 43B in the circumferential direction. there is

By making the outer diameter dimension R1 of the outer end 48a of the core salient pole 48 larger than the inner diameter dimension R2 of the cover inner diameter surface 45f, the core salient pole 48 can be extended to the inside of the guide portion 50 (that is, the slit 51). Therefore, both side surfaces 48 b of the core salient pole 48 facing in the circumferential direction can be brought into contact with the guide portion 50 . As a result, for example, when the rotor 23 rotates, the idling of the magnet cover 45 can be suppressed by the core salient poles 48 .

As shown in FIGS. 3 and 4, a first flange 45b protrudes radially inward from one end 45d of the cylindrical portion 45a opposite to the end face 27a of the rotary shaft 27 (see FIG. 2). The first flange 45b is in contact with the surface of the magnet holding portion 44c (see FIG. 2) of the first magnet holder 44A. A second flange 45c protrudes radially inward from the other end 45e of the cylindrical portion 45a on the side of the end surface 27a of the rotary shaft 27 . The second flange 45c is in contact with the surface of the magnet holding portion 44c of the second magnet holder 44B.
Thus, the first flange 45b contacts the surface of the magnet holding portion 44c of the first magnet holder 44A, and the second flange 45c contacts the surface of the magnet holding portion 44c of the second magnet holder 44B. It is Thereby, the first magnet holder 44A and the second magnet holder 44B are held integrally with the rotor core 42 by the magnet cover 45. As shown in FIG.

That is, the rotor 23 has the magnets 43A and 43B fixed to the rotor core 42 by the cylindrical portion 45a of the magnet cover 45 in a state where the rotor core 42 is fixed to the rotating shaft 27, for example. First and second magnet holders 44A and 44B are fixed to the rotor core 42 by a first flange 45b and a second flange 45c of the magnet cover 45, respectively.
As a result, the rotor 23 is integrally assembled by the rotary shaft 27, the rotor core 42, the magnets 43A and 43B, the first and second magnet holders 44A and 44B, and the magnet cover 45. As shown in FIG.

<How to assemble the magnet cover>
As shown in FIGS. 4 and 5, the first magnet holder 44A is in contact with the core end surface 42a of the rotor core 42 when the rotor core 42 is fixed to the rotating shaft 27. As shown in FIGS. A second magnet holder 44B is in contact with the core end face 42b of the rotor core 42. As shown in FIG. Further, magnets 43A and 43B are arranged axially between the first magnet holder 44A and the second magnet holder 44B. Furthermore, the magnets 43A and 43B are arranged between adjacent core salient poles 48 .

As shown in FIG. 6, a magnet cover 45 is fitted to the magnets 43A and 43B. Here, the magnet cover 45 before being fitted to the magnets 43A and 43B has a shape that expands radially outward in a state where the second flange 45c on the other end 45e side is not crimped as indicated by the imaginary line. formed.
In this state, the second flange 45c of the magnet cover 45 is fitted in the arrow A direction to the outer diameter surfaces 43d (see FIG. 4) of the magnets 43A and 43B via the first magnet holder 44A. As a result, the cylindrical portion 45a of the magnet cover 45 is press-fitted onto the outer diameter surfaces 43d (particularly, the midpoints 43e (see FIG. 7)) of the magnets 43A and 43B.

Here, the magnet cover 45 is expanded radially outward in an inclined manner in a state in which the second flange 45c on the side of the other end 45e is not crimped. Therefore, when the second flange 45c of the magnet cover 45 is fitted to the outer diameter surface 43d of the magnets 43A and 43B via the first magnet holder 44A in the direction of the arrow A, the second flange 45c is positioned as the core salient pole. Interference (contact) with the outer end 48a of 48 can be avoided. As a result, the cylindrical portion 45a of the magnet cover 45 can be fitted to the outer diameter surfaces 43d of the magnets 43A and 43B while being press-fitted.

In this state, the second flange 45c of the magnet cover 45 protrudes below the second magnet holder 44B. By crimping the protruding second flange 45c of the magnet cover 45 radially inward, the second flange 45c comes into contact with the surface of the magnet holding portion 44c (see FIG. 4) of the second magnet holder 44B. )do.
As shown in FIGS. 3 and 4, the rotary shaft 27, rotor core 42, magnets 43A and 43B, first and second magnet holders 44A and 44B, and magnet cover 45 are integrally assembled to the rotor 23. As shown in FIGS.

<Reducer part>
As shown in FIG. 2 , the speed reducer section 30 includes a worm shaft 31 and a worm wheel 32 that meshes with the worm shaft 31 .
The worm shaft 31 is formed as a part of the rotating shaft 27 by forming a spirally continuous worm gear portion 31g on the outer peripheral surface of the rotating shaft 27 of the motor portion 20 at the intermediate portion of the bearing portions 16A and 16B. It is
The worm gear portion 31g is formed such that its outer diameter is larger than the outer diameter of the worm shaft 31 (rotating shaft 27). Such a worm gear portion 31g is formed by rolling.
The worm shaft 31 may be configured separately from the rotating shaft 27 of the motor unit 20, and the worm shaft 31 and the rotating shaft 27 may be integrated by connecting them.

The worm wheel 32 is disk-shaped and has an outer peripheral gear portion 32g that meshes with the worm gear portion 31g of the worm shaft 31 on its outer peripheral surface. The worm wheel 32 is housed in the wheel housing recess 15 of the reduction gear housing 13 of the housing body 11 .
An output shaft 33 projecting from the center of the worm wheel 32 in the radial direction is provided on the side of the worm wheel 32 facing the bottom portion 13b of the speed reducer accommodating portion 13 . The output shaft 33 is arranged coaxially with the rotation center of the worm wheel 32 . A distal end portion of the output shaft 33 protrudes outside the housing body 11 through a through hole of a boss portion 19 formed in the housing body 11 . A spline 33a that can be connected to an electrical component (not shown) is formed at the tip of the output shaft 33 .

<Operation of motor with reducer>
Next, the operation of the motor 1 with a speed reducer will be described.
In the motor 1 with a speed reducer, a predetermined magnetic field is formed in the stator 22 (teeth 25) when electric power is supplied to each winding 26 of the motor section 20 from a controller section (not shown). Receiving this magnetic field, magnetic attraction and repulsion are generated between the magnetic field and the magnets 43A and 43B of the rotor 23 . This causes the rotor 23 to rotate continuously.

As shown in FIG. 3, the outer ends 48a of the salient core poles 48 are entirely exposed from the guide portion 50 of the magnet cover 45 to the outside. As a result, the air gear-up between the outer ends 48a of the salient core poles 48 and the inner peripheral surface 22a (see FIG. 2) of the stator 22 can be suppressed, and the motor characteristics (motor torque) can be enhanced.
As shown in FIG. 2, when the rotor 23 rotates, the worm shaft 31 integrated with the rotating shaft 27 rotates, and the worm wheel 32 meshed with the worm shaft 31 rotates. Then, the output shaft 33 connected to the worm wheel 32 rotates to drive desired electrical components.

[Second embodiment]
Next, a second embodiment will be described based on FIG.
FIG. 8 is a perspective view showing the rotor 100 according to the second embodiment of the invention. In the rotor 100 of the second embodiment, the same or similar structural members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 8, the rotor 100 is obtained by replacing the magnet cover 45 of the rotor 23 of the first embodiment with a magnet cover 102, and other configurations are the same as those of the rotor 23 of the first embodiment.

The magnet cover 102 has a plurality of guide portions 104 on the cylindrical portion 45a. The guide portion 104 has a slit 105 formed in a portion of the cylindrical portion 45a facing the outer end 48a of the salient core pole 48. As shown in FIG. The guide portion 104 has an opening 104a that opens (passes through) the other end 45e of the magnet cover 45 in the axial direction and the second flange 45c.
For this reason, when the magnet cover 102 is press-fitted into the magnets 43A and 43B (see FIG. 5), the second flange 45c is formed in a shape that spreads outward in the radial direction, so that the guide portion 104 receives the core from the opening portion 104a. The outer end 48a of the salient pole 48 can be passed through (fitted). As a result, the outer ends 48a of the salient core poles 48 do not interfere with the press-fitting of the magnet cover 102 onto the magnets 43A and 43B.
Furthermore, according to the rotor 100 of the second embodiment, the same effects as those of the rotor 23 of the first embodiment are obtained.

[Modification 1]
As Modified Example 1 of the second embodiment, a retaining ring may be wound in the circumferential direction around the other end 45e of the cylindrical portion 45a on the side of the second flange 45c. Thereby, for example, when the rotor 100 rotates, the other end 45e and the second flange 45c of the magnet cover 102 can be held by the second magnet holder 44B.

[Modification 2]
Further, as a modification 2 of the second embodiment, the guide portion 104 may be formed with openings that open (through) the one end 45d of the magnet cover 45 in the axial direction and the first flange 45b (see FIG. 4). good. In this case, like the other end 45e on the side of the second flange 45c, the one end 45d on the side of the first flange 45b is also wound with a retaining ring in the circumferential direction. Thereby, for example, when the rotor 100 rotates, the one end 45d and the first flange 45b of the magnet cover 102 can be held by the second magnet holder 44A (see FIG. 4).

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, the case where the motor 1 with a speed reducer serves as a drive source for electrical components mounted on a vehicle (for example, wipers, power windows, sunroofs, electric seats, etc.) has been described. However, it is not limited to this, and the motor 1 with a speed reducer can be used in various electric devices. In addition, only the motor section 20 can be used in various electric devices.

DESCRIPTION OF SYMBOLS 1... Motor with reduction gear (motor), 20... Motor part (motor), 22... Stator, 23... Rotor, 25... Teeth, 26... Winding (coil), 27... Rotating shaft, 42... Rotor core, 43A, 43B ... Magnet 43d ... Outer diameter surface (peripheral surface) of magnet 45, 102 ... Magnet cover 45d ... One end of magnet cover (one end of both ends of magnet cover) 45e ... Other end of magnet cover (of magnet cover) other end of both ends), 45f... inner diameter surface of cover (inner diameter surface of magnet cover), 47... base end of core, 47b... outer peripheral surface of base end of core (outer periphery of rotor core), 48... core salient pole ( salient pole), 48a... outer end (outer end) of core salient pole, 50, 104... guide portion, 50a... first slit end (one end of both ends of guide portion), 50b... second slit end (guide portion the other end of both ends), 51, 105... slit, 104a... opening, L1... first axial dimension (length in axial direction), L2... second axial dimension (length in axial direction), L3... Third axial dimension (length in axial direction), R1... Outer dimension, R2... Inner diameter dimension

Claims (5)

an annular stator having a plurality of teeth;
a coil wound around the teeth;
a rotor that rotates about its axis with respect to the stator;
with
The rotor is
a rotating shaft that rotates around the axis;
It has a plurality of salient poles that are supported so as to rotate integrally with the rotating shaft and protrude outward in the axial direction and the radial direction orthogonal to the rotating direction at intervals in the rotating direction of the rotating shaft. a rotor core;
a plurality of magnets disposed between the adjacent salient poles in the rotating direction of the rotating shaft on the outer peripheral portion of the rotor core;
a magnet cover that covers the outer peripheral surface of the magnet;
with
The magnet cover has a guide portion formed with a slit along the axial direction so that at least all of the outer ends of the salient poles facing the stator in the radial direction are exposed. . 2. The salient pole according to claim 1, wherein the outer diameter of an imaginary circle passing through the outermost end in the radial direction of the outer end of the salient pole is larger than the inner diameter of the inner diameter surface of the magnet cover. motor. The length of the guide portion in the axial direction is smaller than the length of the magnet cover in the axial direction so that the guide portion is arranged between both ends of the magnet cover in the axial direction. A motor according to claim 1 or 2. The salient pole is
4. The length of the salient pole in the axial direction is smaller than the length of the guide portion in the axial direction so as to be disposed between both ends of the guide portion in the axial direction. motor as described. 3. The guide part according to claim 1, wherein the guide part is formed at one end of both ends of the magnet cover in the axial direction and has an opening through which the outer ends of the salient poles can pass. motor.

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