JP2574125B2 - Motor and assembly method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor and a method for assembling the same, and more particularly, to a motor having a stator yoke provided on the outer periphery of a rotor having a multipolar magnetized outer surface so as to face the outer periphery of the rotor. The present invention relates to a motor having a configuration in which a stator integrally formed of a wound mold material is arranged and a method of assembling the motor.

[0002]

2. Description of the Related Art FIG. 12 shows a block diagram of a conventional PM (permanent magnet) type step motor.

A conventional PM type step motor includes two pairs of stator yokes 44 and 45 integrally formed of a molding material in which coils 42 and 43 are wound around a rotor 41 whose outer peripheral surface is multipolar magnetized. A stator 4 having a configuration provided to face the outer periphery of the rotor 1 is disposed via an air gap.

An alternating magnetic field is generated in the stator yokes 44 and 45 by passing a constant current through the coils 42 and 43 alternately to rotate the rotor 41. At this time, the rotor 4
1 also moves up and down due to the alternating magnetic field. In order to suppress this vertical movement, the spring 46 constantly applies a pressing force to the rotor 41.

The bearing 47 is fixed to a fixed plate 49 made of a soft magnetic material to support a shaft 48 provided on the rotor 41. Another bearing 50 is fixed to a bush 51. The bush 51 is fixed to the stator 4.

In order to effectively utilize the alternating magnetic field generated by the stator yokes 44, 45, a case 52 made of a soft magnetic material is set so as to contact the outer periphery of the stator yokes 44, 45. The fixing of the fixing plate 49 and the case 52 is performed as follows.
This is performed by caulking the upper edge 52a of the case 52.

[0007] A protruding portion 53 that abuts against the stator yoke 44a is provided on the peripheral edge of the fixed plate 49 so that the fixed plate 49 is not deformed during crimping.

In such a conventional PM type stepping motor, in order to effectively utilize the alternating magnetic field and suppress the variation in the output torque, the stator 52 must be so arranged that the outer circumferences of the stator yokes 44 and 45 and the case 52 come into contact with each other. York 4
The outer diameter of 4,45 and the inner diameter of the case 11 had to be strictly controlled.

[0009]

However, the conventional PM
In order to reduce the variation in output torque, the size of the stator yoke and the case had to be strictly controlled in order to reduce the variation in output torque. There are problems such as low efficiency and difficulty in reducing cost.

[0010] The present invention has been made in view of the above points, and an object of the present invention is to provide a motor and a method for assembling the same, which can improve manufacturing efficiency and assembly efficiency without deteriorating the performance of parts.

[0011]

According to the first aspect of the present invention, there is provided a stator yoke portion surrounding an outer periphery of a rotor;
In a motor comprising a coil wound around the stator yoke portion and a fixed plate fixed to the stator yoke portion and rotatably holding a rotating shaft of the rotor, the motor is provided integrally with an outer peripheral portion of the fixed plate. A yoke portion engaged with the stator yoke portion on the outer surface of the stator yoke to form a magnetic path together with the stator yoke portion.

Further, the invention is characterized in that the stator yoke portion has an engagement portion which engages with the yoke portion and regulates the movement of the yoke portion in the center direction of the stator yoke portion.

According to a third aspect of the present invention, the stator yoke portion is formed by laminating a plurality of pairs of stator yokes in an axial direction of the rotor, and the yoke portion is engaged between the stator yokes of the plurality of pairs of stator yokes. And the engagement portion with the stator yoke increases as the distance from the fixing plate increases.

According to a fourth aspect of the present invention, in the method for assembling the motor, the yoke portion is bent from a position which is the same as or inside the end face of the engagement portion with the stator yoke portion, and then the stator yoke portion and the yoke are bent. A gap is formed between the part and
The yoke portion and the stator yoke portion are engaged by being bent so as to be parallel to the side surface of the stator yoke portion and pressing the yoke portion in a direction perpendicular to the fixing plate. I do.

[0015]

According to the first to third aspects, the yoke portion provided integrally with the fixed plate is engaged with the stator yoke portion to measure magnetic coupling with the stator yoke portion. Can be reliably magnetically coupled.

According to the second aspect, the yoke portion can be restricted by the outer peripheral portion of the stator yoke portion during engagement.
The contact of the yoke with the coil wound around the inner periphery of the stator can be prevented.

According to the third aspect of the present invention, the portion closer to the fixed plate where the magnetic influence of the fixed plate is larger is made smaller in the engagement portion between the yoke portion and the stator yoke portion. And magnetic coupling can be balanced.

According to the fourth aspect, the yoke and the stator yoke can be engaged by pressing the yoke in a direction perpendicular to the fixing plate.

[0019]

1 is an exploded perspective view of a first embodiment of the present invention, and FIG. 2 is an assembly configuration diagram of the first embodiment of the present invention. The PM (permanent magnet) type step motor 1 of the present embodiment includes a rotor 2, a stator 3, a case 4, and a fixed plate 5.

The rotor 2 has a cylindrical shape, and its outer peripheral surface is a rotor magnet 6 made of a multipolar magnetized permanent magnet.
And a rotating shaft 7 that passes through the center of the rotor magnet 6 and is fixed to the rotor magnet 6.
Are rotatably supported by a bearing member 8 fixed to the fixing plate 5 and a bearing portion 9 formed on the bottom surface of the case 4, and the rotor magnet 6 is disposed on the field generating portion 10 of the stator 3.

The stator 3 includes two pairs of stator yokes 11, 1
2 are laminated and arranged, and are integrally molded with a molding material 13.
4, 15 are wound.

An output terminal 16 for outputting the coils 14 and 15 to the outside is formed integrally with a part of the outer peripheral portion of the stator 3 by a molding material.

A connecting wire 17 is fixed to the output terminal section 16, and the coils 14 and 15 are connected to the connecting wire 17 and connected to the outside via the connecting wire 17.

Notch portions 18 and 19 for engaging with the fixing plate 5 are formed on the outer peripheral portions of the stator yokes 11 and 12 at positions facing each other.

Further, the molding material 1 is provided on the upper surface of the stator 3.
3, a projection 20 for positioning with the fixing plate 5
Are formed. Also, the coils 14 and 15 of the stator 3
A regulating step 13a is formed by the molding material 13 and the stator yokes 11 and 12 on the outer peripheral portion of the winding portion.

FIG. 2 is a plan view of the fixed plate 5 in a developed state. The fixed plate 5 is formed by stamping a plate made of a soft magnetic material by press working or the like.
23, and yoke portions 24 and 25.

The central portion of the flat plate portion 21 is fitted with a central hole 21a for fixing the bearing member 8 by press-fitting, and a projection 20 of the stator 3 is eccentric from the center.
A hole 21b for positioning with respect to the stator 3 is formed in the peripheral edge portion.
A convex portion 21c formed to protrude in the direction, and a concave portion 21d formed on the outer peripheral portion and engaged with the output terminal portion 16 formed on the stator 3 are formed.

The fixing portion 22 is formed so as to protrude from the outer periphery of the flat plate portion 21 and has a hole portion 22a for screwing to an external mechanism.
23a are formed.

The yoke portions 24 and 25 are formed so as to protrude from the outer periphery of the flat plate portion 21, and bend portions 24 a and 25 a for bending the yoke portions 24 and 25 in a direction orthogonal to the upper plate portion 21.
The engaging portions 24b and 25b which engage with the notches 18 and 19 of the stator yoke 11 and the outer periphery of the winding portion of the coil 14 of the stator yoke 11 are engaged.

The arc-shaped portions 24c and 25c, the engaging portions 24d and 25d which engage with the notches 18 formed in the laminated portion of the stator yoke 11 and the stator yoke 12, and the winding portion of the coil 15 of the stator yoke 12 Arc-shaped part 2 to be engaged
4e, 25e, engaging portions 24f, 25f engaging with the notch portion 18 of the stator yoke 12, and claws 24g, 2 engaging with the case 4 and holding the fixing plate 5 and the stator 3 in the case 4.
It consists of 5g.

The arc portions 24c, 25c and the arc portion 24
e, the ratio to 25e is set to about 1: 3, about 1: 2, etc.,
The distance from the flat plate portion 21 is set to be longer.

FIG. 3 is a view for explaining a method of connecting the fixed plate 5 and the stator 3. 4 and 5 show an assembly configuration diagram of the first embodiment of the present invention, and FIG. 6 shows a sectional view of a main part. When connecting the fixed plate 5 to the stator 3, first, the flat plate portion 21
The hole 21b of the flat plate 21 and the projection 20 of the stator 3 are engaged with the lower surface of the stator 3 and the upper surface of the stator 3, and the recess 21d of the flat plate 21 is engaged with the output terminal 16 of the stator 3. After that, the yoke portions 24 and 25 are bent into the bent portions 24a and 2b.
5a is bent in the directions of arrows A and B.

At this time, the bending shape of the yokes 24 and 25 is set such that the bending start position is the same as or inside the radial end face position of the positioning notch 18 on the upper part of the stator yoke 11, and from there. Diagonally down (directions of arrows A and B)
And, while providing an appropriate gap from the outer peripheral surfaces of the stator yokes 11, 12, gradually bend so as to be perpendicular to the flat plate portion 21.

The arc portions 24c, 25c, 24e, 2
5e is previously curved so as to form a circle having a radius obtained by adding the gap between the radii of the stator yokes 11 and 12 to the gap. Due to this bent shape, the stator 3 is fixed to the fixing plate 5 during assembly.
Easier to insert into

Next, the arc-shaped portions 2 of the yokes 24, 25
4c, 24e, 25c, 25e are connected to the stator yoke 11,
12 and then pushed down from the outer peripheral direction. At this time, simultaneously, the stator yokes 11, 1
2 Arc-shaped portions 24c, 24e, 25c,
25e is molded. At this time, the stator yoke 1
The notch 18 and the yokes 24, 25 formed in
Engagement portions 24b, 24d, 24f, 25b,
25d, 25f are engaged with each other, and the arc-shaped portions 24c, 24e,
Positioning of the stators 25c, 25e with respect to the stator 3 is performed, and the arc-shaped portions 24c, 24e, 25c, 25e are formed.
The stator yoke 11, so that the inner surface does not contact the outer periphery of the coil,
A regulation step 13a is provided and regulated by 12 or a mold material. As shown in FIG. 4, the stator yokes 11, 12 are reliably magnetically coupled by the yoke portions 24, 25, and the coils 14, 1 are formed.
5 alternately apply a constant current to the stator yoke 1.
The alternating magnetic field generated in 1, 1 can be effectively used.

The stator 3 and the fixed plate 5 which are connected to each other support the rotating shaft 7 of the rotor 2 with a bearing member 8 while simultaneously rotating the rotor magnet 6 of the rotor 2 with the field generator 10 of the stator 3.
, And then stored in the case 4.

At this time, the rotor 2 inserts the rotating shaft 7 into the bearing member 8 via the spring 26 and the plate 27 in order to suppress the vertical movement due to the alternating magnetic field, and constantly applies a pressing force to the rotor 2.

The case 4 is made of a resin material, and has a bearing fixing portion 9 to which a bearing member is fixed at the center of the bottom surface, a cutout portion 28 on the side surface for outputting the output terminal portion 16 of the stator 3 to the outside, and a peripheral edge of the bottom surface. Holes 29, 30 which engage with the claw portions 24g, 25g provided at the tips of the yoke portions 24, 25 of the fixing plate 5 at the portions.
Are formed.

The stator 3 and the fixed plate 5 are such that the output terminal 16 of the stator 3 is engaged with the notch 28 of the case 4, the rotating shaft 7 of the rotor 2 is engaged with the bearing 9 of the case 4, And a claw portion 24 formed at the tip of each of the yoke portions 24 and 25 of the fixing plate 5.
g and 25g are housed in the case 4 so as to engage with the engagement holes 29 and 30 of the case 4, and are held in the case 4 by caulking the claws 24g and 25g outward.

FIG. 7 shows the angle with respect to the number of steps of the rotor 2 when the ratio of the length of the arc-shaped portions 24c, 25c of the yokes 24, 25 of the fixed plate 5 to the arc-shaped portions 24e, 25e is used as a parameter. FIG. 4 shows a characteristic diagram of the error of FIG.

In the figure, the squares indicate (the arc-shaped portions 24c, 25
c): Characteristics when (arc portions 24e, 25e) = 1: 3, 1 indicates characteristics when 1: 2, and ◇ indicates characteristics when 1: 4.

As shown in the figure, when the ratio is 1: 2, the alternating magnetic field is most balanced, and the error is minimized.

FIG. 8 shows a characteristic diagram of the output torque with respect to the length ratio of the arc portions 24c, 25c and the arc portions 24e, 25e. As shown in FIG. 8, when the ratio is 1: 1.4, the largest output torque is obtained.

As described above, when it is desired to reduce the angle error, the arc-shaped portions 24c and 25c and the arc-shaped portions 24e and 25e
Is set to 1: 2, and if it is desired to increase the output torque, it may be set to 1: 1.4.

FIG. 9 is an exploded perspective view of a second embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is slightly different from the first embodiment in the shapes of the fixing plate and the case.

FIG. 10 shows a configuration diagram of the fixing plate 32 of this embodiment. The fixing plate 32 of the present embodiment is provided with the claw portions 24 provided at the distal ends of the yoke portions 24 and 25 of the fixing plate 5 shown in FIG.
g and 25g are omitted, and the other configuration is exactly the same as the fixing plate 5 of the first embodiment.

The case 33 of this embodiment eliminates the engagement holes 29 and 30 formed in the peripheral edge of the bottom surface of the case 4 shown in FIG.
Holes 34a, 35a having the same shape and substantially the same diameter as
Are formed integrally with each other.

As described above, in this embodiment, the case 33 is configured to be attached by screwing the case 33 together with the fixing plate 32 when attaching the motor.

In this embodiment, as shown in FIG. 11, a constant current is alternately applied to the coils 14 and 15 to suppress the vertical movement generated in the rotor 2 when an alternating magnetic field is generated in the stator yokes 11 and 12. Instead of the spring 26 and the plate 27, high-viscosity grease 37 is lubricated to the bearing portion 36 of the resin case 33.

[0051]

As described above, according to the first to third aspects of the present invention, the yoke is formed integrally with the fixed plate, and the yoke is engaged with the stator, whereby the stator and the fixed plate can be held. It has such features that the contact between the yoke and the stator can be reliably performed without strict dimensional control and stable performance can be obtained.

According to the fourth aspect, the engagement between the yoke and the stator yoke can be performed only by pressing the yoke in the direction perpendicular to the fixing plate, so that the motor can be easily assembled. It has the features of

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment of the present invention.

FIG. 2 is an exploded plan view of a main part of the first embodiment of the present invention.

FIG. 3 is an explanatory view of a main part assembling operation according to the first embodiment of the present invention.

FIG. 4 is a sectional view of the first embodiment of the present invention at the time of assembly.

FIG. 5 is a plan view of the first embodiment of the present invention at the time of assembly.

FIG. 6 is a sectional view of a main part at the time of assembly according to the first embodiment of the present invention.

FIG. 7 is a characteristic diagram of an error with respect to the number of steps according to the first embodiment of the present invention.

FIG. 8 is an output torque characteristic diagram of the first embodiment of the present invention.

FIG. 9 is an exploded perspective view of a second embodiment of the present invention.

FIG. 10 is a developed plan view of a main part of a second embodiment of the present invention.

FIG. 11 is a sectional view of the second embodiment of the present invention at the time of assembly.

FIG. 12 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PM type step motor 2 Rotor 3 Stator 4 Case 5 Fixing plate 6 Rotor magnet 7 Rotation axis

Claims (4)

(57) [Claims] 1. A stator yoke portion surrounding an outer periphery of a rotor, a coil wound around the stator yoke portion, and a rotating shaft of the rotor fixed to the stator yoke portion so as to be rotatable. A motor comprising a fixed plate for holding, a yoke portion provided integrally with an outer peripheral portion of the fixed plate, engaged with the stator yoke portion on an outer surface of the stator yoke, and forming a magnetic path together with the stator yoke portion. A motor having: 2. The stator according to claim 1, wherein the stator yoke has an engagement portion that engages with the yoke and restricts movement of the yoke in the center direction of the stator yoke. motor. 3. The stator yoke portion is formed by laminating a plurality of pairs of stator yokes in an axial direction of the rotor, and the yoke portion is shaped to engage between the stator yokes of the plurality of pairs of stator yokes. The motor according to claim 1, wherein an engagement portion with the stator yoke is formed to be larger as the distance from the fixing plate increases. 4. A bend is formed between the stator yoke and the yoke after bending the yoke from a position that is the same as or inside the end face of the engagement with the stator yoke. The yoke portion is bent so as to be parallel to the side surface of the stator yoke portion, and the yoke portion and the stator yoke portion are engaged by pressing the yoke portion in a direction perpendicular to the fixing plate. A method for assembling a motor according to claim 1.