JP3118114B2 - Method of manufacturing stator laminate for stepping motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated body of a stator for a stepping motor, and more particularly to a process for creating a cross section of a plurality of small teeth arranged at the tips of a plurality of pole teeth. The present invention relates to a method of manufacturing a laminated body of a stator for a stepping motor by consistently pressing using a shaving method.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 1A and 1B, a laminated body 5 of a stator used for a stepping motor is known.
(FIG. 1 (b)) shows an outer ring yoke part 2, eight pole teeth 3 protruding inward from the inner peripheral surface of the yoke part 2, and a circle at a predetermined interval at the tip of each of the pole teeth 3. A single stator core piece 1 having a predetermined shape such as five small teeth 4 arranged in an arc shape
(FIG. 1A) is formed, and a required number of the core pieces 1 are laminated and fixed.

[0003] A method of manufacturing this kind of laminated body 5 is as follows.
Unnecessary portions such as the center hole 7 and the slot 8 are sequentially punched and removed, and the yoke portion 2 of the outer ring of the iron core piece 1, the pole teeth 3 projecting inward from the inner peripheral surface of the yoke portion 2, and the pole teeth 3 After sequentially shaping the shapes of the small teeth 4 and the like arranged at the tip of the outer ring yoke portion 2 and performing a punching process to form the outer peripheral end surface of the outer ring yoke portion 2 to form a predetermined shape of the single stator core piece 1,
A required number of the core pieces 1 are sequentially laminated and fixed via a caulking projection, or the core pieces 1 are arranged and aligned and welded in the laminating direction to form a laminated body 5. .

However, in a stator for a stepping motor, a minute gap is formed between a rotor having small teeth on the outer circumference and a stator having a plurality of small teeth on the inner circumference (about 0.05 mm for a motor requiring high accuracy). ) Must be retained.

[0005] However, in the conventional punching press method using the progressive punching die described above, due to the accumulation of work hardening and the resulting cracks, the separated cross section of the small teeth at the tips of the pole teeth has a shear plane and a fracture plane. The formation (see FIG. 1 (c)) is unavoidable in the punching process. As a result, the gap becomes uneven, so that the torque in each phase becomes uneven, and there is a disadvantage that the motor performance is reduced. .

As a prior art for solving the above-mentioned drawbacks, Japanese Patent Laid-Open Publication No. Sho 59-56861 discloses a method in which after forming a laminated body of iron core pieces, small teeth formed at the tips of the pole teeth and the inner diameter of the cross section are separately provided. A stator processing method is disclosed in which subsequent processing is performed to achieve predetermined dimensional surface accuracy by machining such as cutting, grinding, and broaching, thereby preventing nonuniform air gaps.

[0007]

However, the above-mentioned prior art method requires a press working step and a mechanical working step, so that the transfer equipment between the steps and the cut surface at the tip of the small teeth are created. However, there is a problem that the productivity of the stator laminate is reduced and the product cost is increased.

Further, after the press working, the inner diameter portion of the laminated body is finished by separate machining, so that the concentricity and the eccentricity between the inner diameter and the outer circumference are reduced during the machining of the inner diameter portion. As a result, there has been a problem that the performance and quality of the stepping motor are deteriorated.

The present invention solves the above-mentioned problems of the prior art and provides a method of manufacturing a laminated body of a stator for a stepping motor, which can improve the productivity of the laminated body and the performance and quality of the stepping motor. To provide.

[0010]

According to a first aspect of the present invention, there is provided a method for manufacturing a stator for a stepping motor, comprising the steps of: forming a yoke portion of a stator from a strip-shaped material; A single stator core piece having a plurality of pole teeth protruding inward from the inner periphery of the pole piece and a plurality of small teeth arranged in an arc at a predetermined interval at the tip of the pole teeth is sequentially laminated and fixed. In the method for manufacturing a laminated body of a stator for a stepping motor configured as described above, the required shape processing for forming the iron core piece while leaving a ring-shaped binder interconnecting the tips of the small teeth of the plurality of pole teeth is performed. Do
An arc-shaped half-punched portion (metal structure is partially connected) is formed on the end face of the tip of each of the small teeth, leaving a shaving allowance, and a cross section of the tip of each of the small teeth is formed by shaving. After removing the binder by performing
A process for forming an outer peripheral end face of the yoke portion is performed to form a single stator core piece, and a stepped motor stator laminate in which the core pieces are sequentially laminated and fixed to a required number or thickness is consistently formed. It is characterized by being formed by press working.

[0011]

In the method of manufacturing a laminated body of a stator for a stepping motor according to the present invention, since a circular binder for interconnecting the tips of the small teeth of the plurality of pole teeth is left, the small teeth are formed. While maintaining the shape and pitch of the tips of the small teeth generated when the tip of the tooth is created, minute shaving chips generated during shaving can be removed in a connected state.

[0012] Further, after forming an arc-shaped half-punched portion on the end face of the tip end of the small tooth, leaving a required shaving allowance,
The shaving process that creates the cross section of the tip of the small teeth allows cutting chips to flow along the surface of the punch and spread, thereby avoiding the accumulation of work hardening that occurs in conventional press working and the resulting breakage. can do.

Further, since the principle of shaving processing for creating a cross section at the tip of a small tooth is used,
The required laminated body can be formed by pressing the laminated body of the stator for the motor using a progressive die apparatus.

[0014]

Next, the details of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a plan view of a laminated body of a stator for a stepping motor, and FIGS. 2 (a) and 2 (b).
FIG. 3A is a schematic view of a process showing a method of manufacturing a stator for a stepping motor according to one embodiment of the present invention.
(B) is a partially enlarged view of an iron core piece in an intermediate step in the same method, and FIG. 4 is a partial cross-sectional view showing a shaving step in the same method.

As shown in FIG. 2, a method for manufacturing a laminated body of a stator for a stepping motor according to an embodiment of the present invention has an arc-shaped structure excluding a required shaping allowance and a shaving allowance. A shaving process for forming a half-blanked portion (a metal structure is partially connected), forming a cross section at the tip of each small tooth to remove a binder, and a laminating assembly for sequentially laminating core pieces are performed. Through the manufacturing process of the steps (1st to 10st), a yoke portion of the stator and a plurality of pole teeth protruding from the band-shaped strip to the inner periphery of the yoke portion are formed in a circular arc shape at a predetermined interval at the tip of the pole teeth. A single stator core piece having a plurality of small teeth, the separation faces of which are cut and formed, is formed, and the core pieces are sequentially laminated and fixed to produce a laminated body of a stator for a stepping motor. Composed To have.

First, the outline of each step will be described. According to the drawings, a first step A is a step of punching a positioning pilot hole for determining a processing position of each step, and a second step B is formed by shape processing. A center hole punching step for forming a stress release to relieve stress and an inner contour of a ring-shaped binder, and a third step C is a slot punching for forming a required number (eight in this embodiment) of pole teeth. Process,
The fourth step D is an idle step, the fifth step E is a slit punching step for forming small teeth and forming a connection base projecting outside the binder connecting the tips of the small teeth, and the sixth step F is lamination. The forming step of the fixing caulking projection, the seventh step G is a half-punching step that leaves a required shaving allowance at the tip of the small tooth,
The eighth step H is a shaving step of cutting and creating a cross section at the tip of the small tooth and removing the binder, the ninth step I is an idle step, and the tenth step J is to form the outer contour of the core piece of the stator. At the same time, a step of sequentially laminating the core pieces to form a laminated body of the stator is provided. Hereinafter, the description of the conventional method of manufacturing by stacking and fixing the iron core pieces will be omitted, and the seventh step G and the eighth step H, which are characteristic parts of the present invention, will be described with reference to FIGS. b), FIG. 4 (a)
To provide an understanding of the present invention.

FIG. 3A is a partially enlarged plan view in which a half blank portion is formed on the intermediate-shaped iron core piece formed in the first to seventh steps, and FIG. It is a fragmentary sectional view.
According to the figure, 31 is a core piece of an intermediate shape, 32 is a center hole, 33 is a yoke, 34 is a pole tooth, 35 is a small tooth, 36 is a binder, 37 is a connection base, 38 is The slot, 39 is a slit, and 40 is a caulking projection.
A solid line P is a half blank portion, and a dashed line S indicates an end face (separation position) of the tip of the small tooth 35.

In the seventh step G, the center hole 32
The first to punch and remove the slot 38 and the slit
After the sixth step, as shown in FIGS. 3A and 3B,
The intermediate core piece 31 is formed by connecting the small teeth 35 formed at the tips of the pole teeth 34 in a ring shape via a connection base 37 formed on the outer periphery of the binder 36. On the upper surface of the connection base 37 of the base 31, a half blanking (step shape) process for forming a half blanked portion P while leaving a required shaving allowance on the end surface of the small teeth 35 was performed, and the metal structure was partially connected. Form a shape. here,
The shaving allowance may vary depending on the material, hardness, and plate thickness, but may be set in the range of 0.02 to 0.05 mm.
Although it differs depending on the hardness and the plate thickness, it may be set in the range of 50 to 60% of the plate thickness. In this step, the tips of the small teeth 35 leave the shaving processing allowance and are connected in a ring shape in a half-punched state, so that the chips generated in the next step of shaving processing can be removed in a connected state and the processing force is reduced. be able to.

Next, FIG. 4A is a partially enlarged sectional view showing an outline of the shaving process. According to the figure, 41 is a shaving punch, 42 is a shaving die, 43
Is a pressure plate (stripper plate),
Here, W is a shaving allowance, T is a half-punched step, and K is shaving-off scrap.

In the eighth step H, FIG.
As shown in the figure, the intermediate-shaped iron core piece 31 formed in the seventh step G, which is transported and positioned in the eighth step H,
Is held down by a stripper plate 43, and shaving is performed by a shaving punch 41 and a shaving die 42 having a clearance narrower than a conventional punching clearance to form an end face of the tip of the small teeth 35. Is performed to remove the binder connecting the tips of the small teeth 35.

Here, the shaving punch 41 bites into the shaving allowance W, and the resulting cutting waste K flows along the lower side of the shaving punch 41, and a crack is realized in the direction of the cutting waste K, thereby causing work hardening. Of the small teeth 35 can be prevented, and a smooth separation surface at the tip of the small teeth 35 can be formed.

[0022]

According to the present invention, fine shaving chips generated when creating the tips of the small teeth can be removed in a connected state, so that the cutting chips can be easily removed, thereby causing damage to the product and the cutting tool due to the cutting chips. Can be prevented from being damaged. Furthermore, since shavings at the time of shaving flow and spread along the surface of the punch, it is possible to avoid the accumulation of work hardening and the occurrence of breakage thereby, so that a separation surface having a good smooth surface at the tips of the small teeth is provided. Can be formed, and the performance of the motor can be improved. Furthermore, since the laminated body of the stator for the stepping motor can be consistently formed by press working using the progressive die apparatus, productivity is remarkably improved, and machining equipment and transfer equipment for forming small tooth cross sections are provided. This eliminates the necessity and improves the economics such as reducing the manufacturing cost.

[0023]

[Brief description of the drawings]

FIG. 1 is a plan view of a laminated body of a stator for a stepping motor according to one embodiment of the present invention.

FIG. 2 is a schematic view of a process showing a method for manufacturing a stator for a stepping motor according to one embodiment of the present invention.

FIG. 3 is a partially enlarged view of an iron core piece in an intermediate step in the method used for carrying out the present invention.

FIG. 4 is a partial sectional view showing a shaving step of the same method used in one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 31 core piece of intermediate shape 32 center hole 33 yoke portion 34 pole tooth 35 small tooth 36 binder 37 connection base 38 slot 39 slit 40 caulking protrusion 41 shaving punch 42 shaving die 43 pressing plate

(56) References JP-A-63-18947 (JP, A) JP-A-54-70016 (JP, A) JP-A-60-6299 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H02K 15/02 H02K 37/04

Claims (1)

(57) [Claims] 1. A stator yoke portion comprising:
A single stator core piece having a plurality of pole teeth protruding inward from the inner periphery of the yoke portion and a plurality of small teeth arranged at a tip end of the pole teeth at predetermined intervals in an arc shape is sequentially provided. In a method of manufacturing a laminated body of a stator for a stepping motor configured by lamination and fixation, it is necessary to form the iron core piece while leaving a ring-shaped binder that interconnects the tips of the small teeth of the plurality of pole teeth. Shape processing, forming an arc-shaped half-punched part (metal structure is partially connected) leaving a shaving allowance on the end face of the tip of each of the small teeth,
After forming the end face of the tip of each of the small teeth by shaving processing and removing the binder, processing to form the outer end face of the yoke portion is performed to form a single stator core piece, Characterized in that the core pieces are sequentially laminated and fixed to a required number or thickness.
A method for manufacturing a laminated body of a stator for a motor.