JPH1169670A - Stator core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator core which can keep its high mechanical dimensional precision and avoid the increase of a magnetic reluctance caused by the extention of a cut part without using a frame with a special construction. SOLUTION: A stripe back yoke 21 having a plurality of teeth 22 is bent at bending parts 23 positioned between the teeth 22 to be deformed into an annular form and housed in a cylindrical frame 11 to form a stator core. In the annularly deformed state, the outer diameter of the back yoke 21 at a part 23b corresponding to the tooth 22 of its other long side part is larger than the outer diameter of the back yoke 21 at a position 23b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator core accommodated in a frame by deforming a back yoke formed in a belt shape in a ring shape.

[0002]

2. Description of the Related Art FIG. 6 is a view showing an example of an electric motor 10 in which a stator core 12 is formed by deforming a belt-like back yoke into an annular shape. That is, the electric motor 10 includes a cylindrical frame 11, a stator core 12 formed along the inner wall surface of the frame 11, and a rotor 13 concentrically and rotatably disposed with respect to the stator core 12. It has. The stator core 12 includes a belt-shaped back core 12a, and includes a plurality of teeth 12b extending on one long side. Teeth 12
b, a bent portion 12c in which a cut 12d is formed
Are formed. The coil 14 is attached to the teeth 12b.

As shown in FIG. 7, the stator core 12 is formed by laminating a plurality of punched members 15 formed by pressing a plate material.
It is formed by bending at the bent portion 12c and deforming into an annular shape. Thereby, the cut 12d is closed. Further, a portion 12e corresponding to the teeth 12b on the other long side of the back core 12a is formed in an arc shape centered on the axis of the frame 11.

[0004]

The above-described conventional stator core 12 has the following problems. That is,
When the back core 12a is bent at the bent portion 12c, the bent portion 12c protrudes and deforms toward the outer peripheral side of the back core 12a as shown in FIG. Therefore, the stator core 12 comes into contact with the frame 11 at a portion 12f corresponding to the bent portion 12c. However, the portion 12f is not formed by press working,
It is generated at the time of bending deformation and has low dimensional accuracy.
For this reason, there is a possibility that the axis of the stator core 12 may deviate from the axis of the frame 11.

On the other hand, the stator core 12 has a frame 11
8A through the portion 12f. For this reason, a force is applied in the direction in which the notch 12d opens, which increases the magnetic resistance and may cause instability. Therefore, performance as an electric motor may be reduced.

Therefore, the portion 12 of the stator core 12
It is necessary to precisely position the axial center line by not contacting the frame f with the frame 11 and abutting the frame 12 with the portion 12e formed by press working. For this reason, as shown in FIG.
a, and the portion 12f of the stator core 12 is
It is conceivable not to make contact with 1.

However, in such a method, new processing must be performed on the frame 11, resulting in problems such as an increase in cost and restrictions on the frame 11.

Accordingly, the present invention provides a stator core which can maintain high mechanical dimensional accuracy of a stator core without using a frame having a special configuration, and can prevent an increase in magnetic resistance due to opening of a cut. It is intended to provide.

[0009]

Means for Solving the Problems In order to solve the above problems and achieve the object, the invention described in claim 1 is a belt-like shape having a plurality of teeth extending from one long side thereof. In the stator core accommodated in a cylindrical frame, the back yoke is deformed into an annular shape by bending the back yoke at a bent portion located between the teeth, and the back yoke is in the annularly deformed state, and The outer diameter at a portion of the side portion corresponding to the teeth is larger than the outer diameter at the bent portion.

According to a second aspect of the present invention, in the first aspect of the present invention, the back yoke has a portion corresponding to the bent portion on the other long side portion. It is formed in a concave shape on the side.

According to a third aspect of the present invention, in the first aspect of the present invention, the portion of the back yoke corresponding to the teeth on the other long side portion is larger than the inner diameter of the frame. It is formed in an arc shape with a small diameter.

According to a fourth aspect of the present invention, in the first aspect of the invention, the center of the back yoke corresponding to the teeth on the other long side is the frame. The portion not corresponding to the teeth is formed in an arc shape whose center point is eccentrically arranged on the frame side.

According to a fifth aspect of the present invention, in the first aspect of the present invention, a cut is formed on the one long side of the bent portion. As a result of taking the above-described means, the following operation occurs. In other words, according to the first aspect of the invention, when the back yoke is deformed in an annular shape, the outer diameter of the other long side portion corresponding to the teeth is larger than the outer diameter of the bent portion. As a result, the protruding portion formed from the bent portion toward the outer periphery does not abut on the frame. For this reason, a part of the back yoke with high dimensional accuracy comes into contact with the protruding portion with low dimensional accuracy, and the axis of the stator core can be positioned with high accuracy.

According to the second aspect of the present invention, the back yoke has a portion corresponding to the bent portion of the other long side portion formed in a concave shape on one long side portion. The outer diameter of the corresponding portion is formed to be larger than the outer diameter of the bent portion.

According to the third aspect of the present invention, the portion corresponding to the teeth on the other long side portion is formed in an arc shape having a diameter smaller than the inner diameter of the frame. The outer diameter is formed larger than the outer diameter at the bent portion.

According to the fourth aspect of the present invention, the back yoke is formed in an arc shape such that a portion corresponding to the teeth on the other long side portion has a center point coincident with the inner diameter of the frame. Is formed in an arc shape in which the center point is eccentrically arranged on the frame side, so that the outer diameter of the portion corresponding to the teeth is formed larger than the outer diameter of the bent portion.

According to the fifth aspect of the present invention, a cut is formed on the one long side of the bent portion.
Since the force acting on the back yoke from the frame acts in the direction of closing the cut, the magnetic resistance can be stabilized and reduced. For this reason, motor characteristics and quality can be improved.

[0018]

FIG. 1 is a sectional view showing a state in which a stator core 20 according to a first embodiment of the present invention is accommodated in a cylindrical frame 11. In this figure, the same reference numerals are given to the same functional portions as those in FIG.

The stator core 20 has a back yoke 21 formed in an annular shape, a plurality of teeth 22 extending to the inner peripheral side of the back yoke 21, and a bent portion provided between the teeth 22 and having a cut 23a. 23 and a coil 24 wound around the teeth 22. The bent portion 23 is provided at a portion 21 a formed in a concave shape from the outer peripheral side of the back yoke 21. The back yoke 2
The portion 21b corresponding to one tooth 22 is the frame 11
Are formed in an arc shape having the same diameter as the inner diameter of the frame 11 and the center thereof as the position of the axis C of the frame 11.

As shown in FIG. 2, the stator core 20 is formed by a stamping member 30 formed by pressing a plate material.
Formed by laminating a plurality of are bent at the bent portion 23 and deformed into an annular shape.

As shown in FIG. 3, when the back yoke 21 is bent at the bent portion 23 and deformed into an annular shape, a portion 23b protruding outward is formed. However, since the bent portion 23 is disposed in advance in the portion 21 a that is formed in a concave shape, the portion 23 b does not protrude to the outer peripheral side than the portion 21 b of the back yoke 21 and does not contact the frame 11. That is, the stator core 20 is located on the
1b comes into contact. Part 2 of back yoke 21
1b has high dimensional accuracy because it is formed by press working.

Therefore, the axis of the stator core 20 can be made to coincide with the axis of the frame 11. In addition, the force received from the frame 11 to the stator core 20 acts as shown by the arrow β in FIG. 3 via the portion 21b, and acts in a direction to close the cut 23a of the bent portion 23. For this reason, mechanical strength is improved. In addition, since the magnetic resistance can be stabilized and reduced, the characteristics and quality of the electric motor can be improved.

FIG. 4 is a cross-sectional view of a main part showing a state in which a stator core 40 according to a second embodiment of the present invention is accommodated in a cylindrical frame 11. Note that FIG.
The same reference numerals are given to the same functional parts as those described above, and the detailed description thereof will be omitted. The inner diameter of the frame 11 is set to a radius R1 about the axis C.

The stator core 40 has a back yoke 41 formed in an annular shape, a plurality of teeth 42 extending to the inner peripheral side of the back yoke 41, and a bent portion provided between the teeth 42 and having a cut 43 a. 43 and a coil (not shown) wound around the teeth 42.

A portion 41a corresponding to the tooth 42 on the other long side of the back yoke 41 is formed in an arc shape, the diameter thereof is set to R2 smaller than R1 described above, and the center thereof is set to the frame 11 described above. Is eccentric to the outer peripheral side with respect to the axis C. Therefore, the central portion 41b of the portion 41a has a shape protruding to the outer peripheral side.

When the back yoke 41 is bent at the bent portion 43 and deformed into an annular shape, the portion 43 protruding to the outer peripheral side is obtained.
b is formed. However, since the portion 41a is formed in an arc shape with a radius R2, the bent portion 43 is shifted toward the inner peripheral side. For this reason, the part 43 b does not protrude to the outer peripheral side from the center part 41 b of the part 41 a of the back yoke 41, and does not contact the frame 11. That is, the center portion 41 b of the portion 41 a of the back yoke 41 corresponding to the teeth 42 of the stator core 40 abuts on the frame 11. Center part 41b of back yoke 41
Since it is a part formed by press working, it has high dimensional accuracy.

Therefore, the axis of the stator core 40 can coincide with the axis of the frame 11. Further, the force applied to the stator core 40 from the frame 11 acts as shown by an arrow γ in FIG. 4 and acts in a direction to close the cut 43 a of the bent portion 43. For this reason, mechanical strength is improved. In addition, since the magnetic resistance can be stabilized and reduced, the characteristics and quality of the electric motor can be improved.

FIG. 5 is a sectional view of a main part showing a state in which a stator core 50 according to a third embodiment of the present invention is accommodated in a cylindrical frame 11. It should be noted that FIG.
The same reference numerals are given to the same functional parts as those described above, and the detailed description thereof will be omitted. The inner diameter of the frame 11 is set to a radius R1 about the axis C.

The stator core 50 has a back yoke 51 formed in an annular shape, a plurality of teeth 52 extending to the inner peripheral side of the back yoke 51, and a bent portion provided between the teeth 52 and having a cut 53 a. 53 and a coil (not shown) wound around the teeth 52.

A portion 51a corresponding to the tooth 52 on the other long side of the back yoke 51 is formed in a substantially arc shape. The diameter of the part 51a near the center part 51b is the same as that of R1 described above, and the center is set to the axis C. On the other hand, the diameter near the end 51c is R3, which is smaller than R1, and its center is the frame 11 described above.
Is eccentric to the outer peripheral side with respect to the axis C. Therefore, the central portion 51b of the portion 51a has a shape protruding to the outer peripheral side.

When the back yoke 51 is bent at the bent portion 53 and deformed into an annular shape, the portion 53 projecting to the outer peripheral side is formed.
b is formed. However, since the end portion 51a is formed in an arc shape with a radius R3, the bent portion 53 comes closer to the inner peripheral side. Therefore, the portion 53b does not protrude outward from the center portion 51b of the portion 51a of the back yoke 51, and does not contact the frame 11. That is, the center portion 51 b of the portion 51 a of the back yoke 51 corresponding to the teeth 52 of the stator core 50 comes into contact with the frame 11. Center part 51b of back yoke 51
Since it is a part formed by press working, it has high dimensional accuracy.

Therefore, the axis of the stator core 50 can be matched with the axis of the frame 11. The force applied to the stator core 50 from the frame 11 acts as shown by an arrow δ in FIG. 5 and acts in a direction to close the cut 53 a of the bent portion 53. For this reason, mechanical strength is improved. In addition, since the magnetic resistance can be stabilized and reduced, the characteristics and quality of the electric motor can be improved. It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

[0033]

According to the first aspect of the present invention, when the back yoke is deformed in an annular shape, the outer diameter of the portion corresponding to the teeth on the other longer side is the outer diameter of the bent portion. Since it is formed so as to be larger than the diameter, the protruding portion formed from the bent portion toward the outer peripheral side does not contact the frame. For this reason, a part of the back yoke with high dimensional accuracy comes into contact with the protruding portion with low dimensional accuracy, and the axis of the stator core can be positioned with high accuracy.

According to the second aspect of the present invention, the portion of the back yoke corresponding to the bent portion of the other long side is formed in a concave shape on one long side. The outer diameter of the portion corresponding to the teeth is formed larger than the outer diameter of the bent portion.

According to the third aspect of the present invention, the portion corresponding to the teeth on the other long side is formed in an arc shape having a diameter smaller than the inner diameter of the frame, and thus corresponds to the teeth. The outer diameter of the portion is formed larger than the outer diameter of the bent portion.

According to the fourth aspect of the present invention, the portion corresponding to the teeth on the other long side of the back yoke is formed in an arc shape such that the center point thereof coincides with the inner diameter of the frame. Since the center portion of the portion not corresponding to the teeth is formed in an arc shape eccentrically arranged on the frame side, the outer diameter of the portion corresponding to the teeth is formed larger than the outer diameter of the bent portion. Become.

According to the fifth aspect of the present invention, since the notch is formed on the one long side of the bent portion, the force acting on the back yoke from the frame acts in the direction to close the notch. Therefore, the magnetic resistance can be stabilized and reduced. For this reason, motor characteristics and quality can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an electric motor in which a stator core according to a first embodiment of the present invention is incorporated.

FIG. 2 is a plan view showing a state before deformation of a punched plate constituting the stator core.

FIG. 3 is a plan view showing a main part of the stator core.

FIG. 4 is a plan view showing a main part of a stator core according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a main part of a stator core according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a main part of an electric motor in which a conventional stator core is incorporated.

FIG. 7 is a plan view showing a state before deformation of a punched plate constituting a conventional stator core.

FIG. 8 is a schematic diagram for explaining a problem in a conventional stator core.

[Explanation of symbols]

 11 Frame 20, 40, 50 Stator core 21, 41, 51 Back yoke 22, 42, 52 Teeth 23, 43, 53 Bent

Claims (5)

[Claims] 1. A belt-shaped back yoke having a plurality of teeth extending from one long side thereof is bent at a bent portion located between the teeth so as to be annularly deformed to form a cylindrical frame. In the stator core housed in the above, the back yoke is in an annularly deformed state,
A stator core, wherein an outer diameter of a portion corresponding to the teeth of the other long side portion is formed to be larger than an outer diameter of the bent portion. 2. The back yoke according to claim 1, wherein a portion corresponding to the bent portion of the other long side portion is formed in a concave shape on the one long side portion. 3. The stator core according to 1. 3. The back yoke according to claim 1, wherein a portion corresponding to the teeth on the other long side portion is formed in an arc shape having a diameter smaller than an inner diameter of the frame. 3. The stator core according to 1. 4. A portion of the back yoke corresponding to the teeth on the other long side portion is formed in an arc shape such that a center point thereof coincides with an inner diameter of the frame, and does not correspond to the teeth. 2. The stator core according to claim 1, wherein the portion is formed in an arc shape whose center point is eccentrically arranged on the frame side. 3. 5. The stator core according to claim 1, wherein a cut is formed in the one long side of the bent portion.