JP2000278893A - Motor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure constant performance not depending on the accuracy of the punching mold. SOLUTION: The end part 30a of a stator teeth 30 and an involute 20b at the internal circumference of a stator core 20 connected to the end part 30a are formed of the involute at the circumference around a rotating shaft C of stator. Since, when the stator teeth 30 rotates, a gap between the involute 20b at the internal circumference of stator core 20 and end part 30a of the stator teeth 30 can be reduced, if the accuracy of stator teeth 30 is low, assembling to the stator core 20 can be realized under the constant joining condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor having a split core formed by punching a steel plate to form a stator core and stator teeth, winding a winding around the stacked stator teeth, and assembling the windings with the stacked stator core. The present invention relates to a method for manufacturing the motor.

[0002]

2. Description of the Related Art In brushless DC motors and DC motors, in order to facilitate the winding operation and improve the space factor, when a silicon steel plate is punched, a stator core and a stator tooth are divided and formed to form a winding. After that, there is a device that adopts a split core method of connecting the two.

[0003] The manufacturing process of the split core will be described with reference to FIG. FIG. 8A shows a silicon steel plate 210 before punching. Here, punching is performed as shown by a broken line in FIG. 8A, and the stator core 2 shown in FIG.
20 and stator teeth 230 shown in FIG. Then, after winding a winding (not shown) on the stator teeth side, as shown in FIG.
The split core is completed by assembling the stator teeth 230 with the zero. Here, on the inner circumference of the stator core 220, a groove 220a formed when the distal end portion 230a of the stator tooth 230 is pulled out, and a groove 220b for assembling the distal end portion 230a are formed. This is because the tip portion 230a cannot be inserted into the groove 220a formed when the tip portion 230a is pulled out during assembly, that is,
This is because when punching out with a die composed of a die and a pin, the tip 230a of the stator tooth 230 can be burred back. By making the groove 220b deeper than the groove 220a, the stator teeth 230
Can be assembled. Then, FIG. 8 (D)
As shown in (2), after assembling the stator teeth 230 to the stator core 220 or at the time of assembling, the stator core 220 and the stator teeth 230 are integrated by performing welding, molding, or the like.

[0004]

However, there is a problem that the performance of the split core is more likely to vary as compared with an integrated core. That is, since the split core is generally formed by stacking 50 or more stator cores and stator teeth, it is necessary to punch out 50 or more silicon steel plates. For the punching, a mold including a die 252 and a pin 250 as shown in FIG. Die 25
2 spreads downward, and when the silicon steel plate is continuously punched, the accuracy is reduced due to the wear of the mold, and the stator teeth 230 are gradually increased, and the leading end 230a of the stator teeth 230 and the groove 220b on the stator core side are formed. Is narrowed, and the stator teeth 23
0 cannot be entered. For this reason, the mold is designed so that the stator teeth are manufactured smaller, and the size of the stator teeth changes between the start of the manufacture of the mold and the end of the life of the mold, and the stator teeth are manufactured. The connection conditions with the stator core have changed, and the performance of the motor has varied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a motor capable of maintaining a constant performance irrespective of the accuracy of a punching die and a method of manufacturing the motor. It is to provide a method.

[0006]

According to the first aspect of the present invention, in order to achieve the above object, a stator core and a stator tooth are formed by punching a steel plate, and a winding is wound around the stacked stator teeth. Motor having a split core assembled to the stator core, wherein the shape of the joint between the stator core and the stator teeth is formed by a circumferential involute centered on the rotation axis of the stator, and the involute of the stator core is: It is a technical feature that it is formed longer than the involute at the tip of the stator teeth.

According to the second aspect of the present invention, a motor having a split core formed by punching a steel plate to form a stator core and stator teeth, winding a winding around the stacked stator teeth, and assembling the windings to the stacked stator cores. The tip of the stator tooth is formed in an arc shape so as to join with the arc shape formed on the inner periphery of the stator core, and the arc of the stator core and the arc of the tip of the stator tooth are centered on the rotation axis of the stator. The arc of the stator core is formed by an arc having a diameter smaller than that of the
It is a technical feature that it is formed longer than the arc of the tip of the stator teeth.

According to a third aspect of the present invention, in the second aspect,
A technical feature is that the arc of the inner circumference of the stator core and the arc of the tip of the stator teeth are formed as arcs of the same diameter.

A fourth aspect of the present invention resides in a method of manufacturing a motor including at least the following steps (A) to (D): (A) a step of punching a steel plate to form a stator core and stator teeth. Forming a tip of the stator teeth in the involute so as to join with an involute shape formed on the inner periphery of the stator core,
(B) a step of winding a winding around the stacked stator teeth, (C) a step of positioning the tip of the stator teeth so as to correspond to an inner periphery of the stacked stator core, and (D) a step of positioning the stator teeth with the stator core. Rotating in a direction in which the gap becomes smaller, and stopping the rotation when the rotation torque reaches a predetermined value.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a motor including at least the following steps (A) to (D): (A) a step of forming a stator core and stator teeth by punching a steel plate. Forming a tip of the stator teeth into an arc shape so as to join with an arc shape formed on the inner periphery of the stator core, (B) winding a winding around the stacked stator teeth, and (C) stacking the stator core. (D) rotating the stator teeth in a direction to reduce the gap between the stator core and the stator core, and stopping the rotation when the rotation torque reaches a predetermined value. Process.

According to the first aspect of the present invention, the shape of the joint between the stator core and the stator teeth is formed by a circumferential involute centered on the rotation axis of the stator. That is, by rotating the stator teeth, the gap between the involute at the inner periphery of the stator core and the involute at the tip of the stator teeth can be reduced, so that even if the accuracy of the stator teeth is low, the stator teeth are fixed to the stator core in a fixed state. Can be assembled. For this reason,
Even if the accuracy of the punching die decreases, the performance of the motor does not deteriorate.

According to the second and third aspects of the present invention, the stator core is joined to the circular arc formed on the inner periphery of the stator core.
The tip of the stator teeth is formed in an arc shape, the arc of the stator core and the arc of the tip of the stator teeth are formed as arcs smaller in diameter than the arc centered on the rotation axis of the stator, and the arc of the stator core is formed by the stator teeth. It is formed longer than the arc at the tip. That is, by rotating the stator teeth, the gap between the arc of the inner circumference of the stator core and the arc of the tip of the stator teeth can be reduced, so that the stator teeth are fixed to the stator core in a fixed state even if the accuracy of the stator teeth is low. Can be assembled. Therefore, even if the accuracy of the punching die is reduced, the performance of the motor is not reduced.

According to the fourth aspect of the present invention, the tip of the stator teeth is positioned so as to correspond to the involute on the inner circumference of the stacked stator cores, and the stator teeth are rotated in a direction in which the gap between the stator core and the stator core is reduced. By stopping the rotation when the predetermined value is reached, a fixed joining state between the stator core and the stator teeth can be obtained. Therefore, even if the accuracy of the punching die is reduced, the performance of the motor is not reduced.

According to the fifth aspect of the present invention, the tips of the stator teeth are positioned so as to correspond to the arcs on the inner periphery of the stacked stator cores, and the stator teeth are rotated in a direction in which the gap with the stator core is reduced, so that the rotational torque is reduced. By stopping the rotation when the predetermined value is reached, a fixed joining state between the stator core and the stator teeth can be obtained. Therefore, even if the accuracy of the punching die is reduced, the performance of the motor is not reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a motor according to an embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a sectional view of the brushless motor according to the first embodiment. The shaft 52 is rotatably supported by the motor housing 56.
A permanent magnet 62 is attached to the outer periphery of the rotor 60 attached to the second rotor 2. A split core 54 is attached to the motor housing 46 so as to face the permanent magnet 62.

FIG. 1A shows a brushless DC shown in FIG.
Silicon steel plate 1 for forming divided core 54 of motor 50
1B shows a stator core 20 punched from the silicon steel plate 10 by a mold (die and pin) (not shown), and FIG. 1C shows a stator tooth 30 punched out.
Is shown. The tip 30a of the stator teeth 30
Is formed by a circumferential involute centered on the rotation axis of the stator. On the other hand, on the inner periphery of the stator core 20, an involute 20 a
And the involute 20a corresponding to the tip portion 30a
The involute 20b is formed longer than the involute 20b.

FIG. 2A shows a stator teeth laminated body 32 formed by laminating a plurality of stator teeth 30 shown in FIG. 1C. On the other hand, FIG.
3B shows a stator core laminate 22 formed by laminating a plurality of stator cores 20 shown in FIG. In the brushless DC motor 50 of the present embodiment, as shown in FIG.
After winding the coil 34 around the stator tooth laminate 32, it is assembled to the stator core laminate 22. That is, since the coil is wound in a state where the distal end portion 30a of the stator tooth 30 is open, the winding operation can be facilitated and the space factor of the coil can be improved.

FIGS. 3 and 4 show the assembly of the stator teeth laminate 32 to the stator core laminate 22.
This will be described with reference to FIG. 3 and 4 show plan views of the stator core laminate 22 and the stator teeth laminate 32. In the drawings, coils are omitted for convenience of illustration. First, as shown in FIG. 3, the stator tooth stack 32 is incorporated into the stator core stack 22 so that the tip 30 a of the stator tooth 30 corresponds to the involute 20 b on the inner periphery of the stator core 20.

In FIG. 4, the stator teeth laminate 32 is rotated counterclockwise so that the gap between the stator teeth laminate 32 and the stator core laminate 22 is reduced, and when the rotational torque reaches a predetermined value, that is, the involute 20 of the stator core 20 is rotated.
b, the distal end portion 30a of the stator teeth 30 is joined, and the rotation is stopped in a state where the rotation torque for rotating the stator teeth stacked body 32 has reached a predetermined value (rotated by θ ′). Thereafter, the stator core laminate 32 and the stator core laminate 22 are solidified or welded with resin to complete the split core 54 described above with reference to FIG.

The involute shapes of the involutes 20a and 20b on the inner periphery of the stator core 20 and the tip 30a of the stator teeth 30 will be described in more detail with reference to FIG. As shown in FIG. 5A, in the present embodiment, the involute 2
0a, 20b and the tip 3 of the stator teeth 30
0a are all formed in an involute shape by the circumference of radius r from the center C of the stator.

The radius r shown in FIGS. 5A and 5B
Let l be the distance from the tangent direction of the circle to the left end of the tip 30a in the drawing, and l 'the distance from the tangent direction of the circle having a radius r to the right end of the tip 30a in the drawing. Here, for example, FIG.
(A), the length a of the involute 20a on the side of the stator core 20 from which the tip portion 30a is punched is 4.4 mm,
The length b of the involute 20b with which the tip 30a abuts is 6.6 mm (b ≒ 1.5a), l is 35 mm, and the radius r of the circle is 2.2 mm. l ′ can be expressed by the following equation 1.

L ′ = l + 2rπ × θ / 360 On the other hand, θ = 2β = 2 · tan ⁻¹ (r / l). Therefore, l ′ is: l ′ = l + tan ⁻¹ (2.2 / 35) × 2/360 × 2 × 2.2π = 35.276

That is, l 'is longer than l by 0.276 mm. Here, the tip 30a is the involute 20a
Stroke X that can move along (see FIG. 5C),
When the tolerance of the stator teeth is ± 0.05 mm, the displacement of the size of the stator teeth due to the wear of the mold can be allowed up to 0.1 mm. Generally 0.1 / 0.276
The relationship of ≒ X / a holds, and X = 0.36a. Here, since X is about a / 3, as described above,
By setting b = 1.5a, the stator teeth 30
The tip portion 30a can be accommodated in the involute 20b up to a displacement of about 0.1 mm, and by rotating the stator teeth 30a as described above with reference to FIG. It can be assembled to the laminate 22. For this reason, even if a dimensional error of the stator teeth 30 occurs due to wear of the mold, a brushless DC motor having the same performance can be manufactured. As a result, in addition to improving the performance of the motor, the usable period can be extended even if the mold is worn.

That is, in the first embodiment, the distal end portion 30a of the stator teeth 30 and the involute 20b on the inner periphery of the stator core 20 connected to the distal end portion 30a form a circle having a radius r about the rotation axis C of the stator. It is formed by a circumferential involute. That is, the stator teeth 30
Is rotated, the involute 20 b on the inner periphery of the stator core 20 and the tip 30
Since the gap of a can be reduced, the stator teeth 30 can be assembled to the stator core 20 in a fixed state even if the accuracy of the stator teeth 30 is low. Therefore, even if the accuracy of the punching die is reduced, the performance of the motor is not reduced.

Next, a motor according to a second embodiment of the present invention will be described. This motor has the same structure as the brushless DC motor of the first embodiment described above with reference to FIG. 6 except for the shape of the split core, and therefore only the configuration of the split core will be described.

FIG. 7 shows a silicon steel plate 110 for forming the split core of the second embodiment. As described above with reference to FIG. 5, the inner periphery of the stator core and the tips of the stator teeth of the first embodiment are formed in an involute shape. On the other hand, in the second embodiment, arcs 120 a and 120 b are formed on the inner periphery of the stator core 120, and the tip 130 a of the stator teeth 130 is formed in an arc shape obtained by punching the arc 120 a of the stator core 120. .

The arcs 120a, 1a of the stator core 120
The arcs of the tip end portion 130a of the stator teeth 130 and 20b are formed as arcs smaller in diameter than the arc centered on the rotation axis C of the stator. That is, the arcs 120a, 12
0b is located at the center on a circle having a radius r1 about the rotation axis C. Also, the arc 120b of the stator core is
The stator teeth 130 are formed longer than the arc of the tip 130a.

The stator core 120 and the stator teeth 130 of the second embodiment are laminated in the same manner as the first embodiment described above with reference to FIGS. When the rotating torque is reduced to a predetermined value, that is, the arc 120 of the stator core 120 is rotated.
The rotation is stopped until the distal end portion 130a of the stator tooth is joined to b. Thereby, a fixed joining state between stator core 120 and stator teeth 130 can be obtained. Thereafter, the stator teeth laminate and the stator core laminate are solidified with a resin to form a core.

In the second embodiment, the distal end portion 130a of the stator tooth 130 is formed in an arc shape so as to join with the shape of the arc 120b formed on the inner periphery of the stator core 120.
b and the arc of the stator teeth tip 130a are formed as arcs smaller in diameter than the arc centered on the rotation axis C of the stator, and the arc 120b of the stator core 120 is
The stator teeth 130 are formed longer than the arc of the tip 130a. For this reason, in FIG. 7, by rotating the stator teeth 130 in the counterclockwise direction, the gap between the arc of the inner periphery of the stator core 120 and the arc of the tip 130a of the stator teeth 130 can be reduced. The stator teeth 130 can be assembled to the stator core 120 in a fixed joint state even if the precision of the stator teeth 130 is low. Therefore, even if the accuracy of the punching die decreases, the performance of the motor does not deteriorate.

[Brief description of the drawings]

FIG. 1A is a plan view of a silicon steel sheet forming a split core according to a first embodiment of the present invention, and FIG.
Is a plan view of a stator core punched from the silicon steel sheet, and FIG. 1C is a plan view of a stator tooth punched from the silicon steel sheet.

FIGS. 2 (A) and 2 (B) are perspective views showing a laminate in which the stator teeth shown in FIG. 1 (C) are laminated, and FIG. 2 (C) is a perspective view of FIG. FIG. 4 is a perspective view showing a laminated body obtained by laminating the stator cores shown in FIG.

FIG. 3 is a plan view of a stator core and stator teeth.

FIG. 4 is a plan view of a stator core and stator teeth.

5 (A), 5 (B), and 5 (C) are illustrations of involute between a stator core and stator teeth.

FIG. 6 is a cross-sectional view of the brushless DC motor according to the first embodiment.

FIG. 7 is a plan view of a stator core and stator teeth according to a second embodiment.

FIG. 8A is a plan view of a silicon steel sheet forming a split core according to the related art, and FIG. 8B is a plan view of a stator core punched out of the silicon steel sheet;
8C is a plan view of a stator tooth punched out of the silicon steel sheet, and FIG. 8D is a plan view of a state where the stator core and the stator tooth are assembled.
(E) is an explanatory view of punching of a silicon steel plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Silicon steel plate 20 Stator core 20a, 20b Involute 30 Stator tooth 30a Tip 50 Brushless DC motor 54 Split core 110 Silicon steel plate 120 Stator core 120a, 120b Arc 130 Stator tooth 130a Tip

Claims (5)

[Claims] 1. A motor having a split core formed by punching a steel sheet to form a stator core and stator teeth, winding a winding around the stacked stator teeth, and then assembling the stator core with the stacked stator cores. The shape of the joint with the teeth
A motor formed of a circumferential involute centered on a rotation axis of a stator, wherein an involute of a stator core is formed to be longer than an involute of a tip of a stator tooth. 2. A motor having a split core formed by punching a steel plate to form a stator core and stator teeth, winding a winding around the stacked stator teeth, and then assembling the stator core with the stacked stator cores. The tip of the stator teeth is formed in an arc shape so as to join with the arc shape formed on the circumference, and the arc of the stator core and the arc of the tip of the stator teeth are smaller in diameter than the arc around the rotation axis of the stator. And the arc of the stator core is formed longer than the arc of the tip of the stator teeth. 3. The motor according to claim 2, wherein the arc of the inner circumference of the stator core and the arc of the tip of the stator teeth are formed with the same diameter. 4. A method of manufacturing a motor including at least the following steps (A) to (D): (A) a step of punching a steel plate to form a stator core and stator teeth, which is formed on an inner periphery of the stator core. Forming the tip of the stator teeth in the involute so as to join with the involute shape,
(B) a step of winding a winding around the stacked stator teeth, (C) a step of positioning the tip of the stator teeth so as to correspond to an inner periphery of the stacked stator core, and (D) a step of positioning the stator teeth with the stator core. Rotating in a direction in which the gap becomes smaller, and stopping the rotation when the rotation torque reaches a predetermined value. 5. A method for manufacturing a motor comprising at least the following steps (A) to (D): (A) a step of punching a steel plate to form a stator core and stator teeth, which is formed on an inner periphery of the stator core. Forming a tip of the stator teeth in an arc shape so as to join with the formed arc shape, (B) winding a winding around the stacked stator teeth, and (C) forming an arc on the inner periphery of the stacked stator cores. (D) a step of rotating the stator teeth in a direction in which a gap between the stator teeth and the stator core is reduced, and stopping the rotation when the rotation torque reaches a predetermined value.