JP2000050556A - Armature for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of an unfilled part by making the thickness of a shell of a bobbin on which a coil wire material is wound larger than that of a collar for suppressing the wire material from the outside, thereby simultaneously filling in an overall bobbin. SOLUTION: The thickness T of a shell 24 of a linear shape of a base end side of a bobbin 23 is made thicker than a thickness (t) of a collar 26 or a cover 27 of a bent shape at an end side of the bobbin 23. In the case of forming a dividing unit 21 of a coil bobbin, when a heated and melted resin is filled in a cavity from a gate 44A, the resin flows as shown by an arrow, and is filled in an overall cavity. Thus, since the thickness T of the shell 24 is made thicker than that (t) of the collar 26 or the cover 27, it can prevent the melted resin from being previously filled at the end, and hence the shell 24 of an intermediate site and the collar 26 and the cover 27 of an end site are simultaneously completely filled. Therefore, no unfilled part occurs at the shell 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an armature for a motor, and more particularly to an improvement in a coil bobbin, and more particularly to an effective armature for a thin motor used in an electric lawn mower and the like.

[0002]

2. Description of the Related Art An electric lawn mower and the like sometimes use a thin motor in which a stator and an armature which form a field pole by a permanent magnet are thinned in an axial direction.

[0003] As an armature mounted on such a thin motor, a core in which a plurality of salient poles are radially protruded from the outer periphery of a base formed in a disk shape at intervals in the circumferential direction, Some include a coil bobbin wound around a core and wound with a coil wire. The coil bobbin is formed by using a resin having an insulating property, and a pair of divided bodies formed in a shape divided into two in the axial direction of the core are aligned so as to face each other. The divided body includes a ring portion covering the base of the core, and a plurality of bobbin portions projecting radially from the outer periphery of the ring portion and covering the salient pole portions of the core.

[0004]

However, in the above-mentioned conventional armature of a thin motor, when a divided body of the coil bobbin is formed by using resin, the radial dimension of the divided body is large. The inventor of the present invention has found that an unfilled portion may be generated in a body portion of a thin coil bobbin around which a coil wire in a bobbin portion is wound. If an unfilled portion occurs in the body of the bobbin portion of the coil bobbin, a short circuit between the coil wire and the core may occur in the unfilled portion of the body when the coil wire is wound around the bobbin.

An object of the present invention is to provide a motor armature which can prevent a short circuit from occurring by preventing an unfilled portion from being generated on a coil bobbin.

[0006]

An armature of a motor according to the present invention comprises: a core having a plurality of salient poles radially protruding from an outer periphery of a base formed in a disk shape; A coil bobbin around which a coil wire is wound, wherein the coil bobbin is constituted by opposing a pair of divided bodies formed into a shape divided into two in the axial direction of the core, and the divided body is formed by the core In the armature of the motor, each of which has a ring portion covering the base portion of the above, and a plurality of bobbin portions projecting radially on the outer periphery of the ring portion and covering each salient pole portion of the core, The thickness of the body of the divided body around which the coil wire is wound is set to be greater than the thickness of the flange that presses the coil wire from the outside.

According to the above-mentioned means, when the divided body of the coil bobbin is formed, the molten resin injected from the gate is in a state of being sequentially filled from the upstream side in the body of the bobbin portion. Complete filling simultaneously. Therefore, generation of an unfilled portion in the bobbin portion can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the present embodiment, the armature of the thin motor according to the present invention is formed thin in the axial direction (hereinafter referred to as the vertical direction) as shown in FIG.
That is, the armature 10 has the commutator 2
And is fixed together with the two bearings 3 and 4, and is formed in a disk shape whose outer diameter is sufficiently larger than the outer diameter of the rotating shaft 1. The armature 10 has salient pole portions 13 which constitute magnetic poles.
, A coil bobbin 20 covered on the core 11, and a coil wire 30 wound around the coil bobbin 20
And

The core 11 is formed by laminating thin plates formed by using a magnetic material and is integrated with each other.
As shown in FIG. 1, a base 12 formed in a disk shape is provided. A plurality of salient pole portions 13 are radially projected at equal intervals in the circumferential direction on the outer periphery of the base portion 12, and each salient pole portion 13 has a substantially T-shape as shown in FIG. Each is formed in a columnar shape. The group of T-shaped heads 14 of the salient pole portions 13 are located on the same radius, and an appropriate space is interposed between the adjacent heads 14, 14.

A shaft hole 15 is formed at the center of the base 12 of the core 11, and the armature 10 is fixed to the rotation shaft 1 by press-fitting the rotation shaft 1 into the shaft hole 15.

As shown in FIGS. 2 and 3, the coil bobbin 20 is composed of a pair of upper and lower divided bodies 21 and 21, and the two divided bodies 21 and 21 are made of an insulating resin. Molded by injection molding. The two divided bodies 21 and 21 are formed into the same shape in which the coil bobbin 20 is divided into two in the thickness direction and is vertically symmetrical with each other. That is, the pair of divided bodies 21 constituting the coil bobbin 20 are molded by a molding die having a similar configuration.

The sectional body 21 of the coil bobbin 20 has a cross section L
It has a ring portion 22 formed in a short cylindrical shape with a thin and thick wall shape. The inner diameter of the cylindrical portion of the ring portion 22 is set to be slightly larger than the outer diameter of the base portion 12 of the core 11. It is set so as to be 以下 or less of the dimension L in the direction. The inner diameter D of the flange of the ring portion 22 is larger than the rotation shaft 1, and
2 are set so as to cover the upper and lower surfaces substantially to the center. In the present embodiment, the pair of divided bodies 21 and 21 are disposed with a slight gap therebetween in consideration of a dimensional error of the resin mold.

A plurality of bobbin portions 23 are radially protruded from the outer periphery of the ring portion 22 of the divided body 21 so as to correspond to the salient pole portions 13 of the core 11. The bobbin portion 23 includes a body portion 24 around which the coil wire 30 is wound. The body portion 24 is formed in a substantially rectangular parallelepiped box shape that can accommodate the salient pole portion 13. In order to facilitate the insertion of the salient pole portion 13,
The inner diameter of 4 is set slightly larger in the circumferential direction than the outer diameter of the salient pole portion 13 and slightly smaller in the radial direction.

As shown in FIG. 3, an end surface (upper surface or lower surface) of the body portion 24 has a projecting piece 25 protruding radially outward at a constant width at an outer end side. The piece 25 can be brought into contact with the end surface (upper surface or lower surface) of the head 14 of the salient pole 13.

A pair of flanges 26, 26 are provided on both side walls of the body 24 at a constant width in a tangentially outward direction along the outer edges, respectively. The salient pole 13 is formed so as to oppose both ends of the head 14 with a certain gap. The width between the two flanges 26 in the body 24 is the salient pole 13 of the core 11.
Is set to be substantially equal to the width of the head 14 at.

A cover portion 27 is provided on each of the flange portions 26 and 26 at a substantially constant width in a radially outward direction along an end side. Part 26
Is set to be equal to or less than the gap between

In the present embodiment, the thickness T of the body portion 24, which is on the base end side of the bobbin portion 23 and is linear, is on the distal end side of the bobbin portion 23 and is a curved portion. The thickness is set larger than the thickness t of the flange 26 and the cover 27.

Next, a method of forming the divided body of the coil bobbin according to the above configuration will be described with reference to FIGS.

As shown in FIG. 4, on the mating surface of the upper die 41 and the lower die 42 of the forming die 40 for forming the divided body 21 of the coil bobbin 20, the divided body 2 of the coil bobbin 20 is provided.
1 is formed. In the molding die 40, the closed end surface (upper surface or lower surface) of the divided body 21 is disposed on the mating surface of the cavity 43 so that the divided body 21 can be die-cut. In the mold 40, a plurality of gates 44 for injecting resin into the cavity 43 are provided.
The portions 22A corresponding to one ring portion 22 are arranged at equal intervals in the circumferential direction. In FIGS. 2 and 5,
Reference numeral 44A indicates a gate mark.

In the present embodiment, the width TA of the portion 24A of the cavity 43 where the body portion 24 is formed is defined.
Is a portion 26A for forming the flange portion 26 and the cover portion 27.
And 27A are wider than the width tA. That is, the flow path resistance of the portion 24A of the bobbin portion 23 where the body portion 24 is formed is set to be smaller than those of the portions 26A and 27A where the flange portion 26 and the cover portion 27 are formed.

When the resin 45 heated and melted is injected from the gate 44 into the cavity 43 when the divided body 21 of the coil bobbin 20 is formed, the injected molten resin 45
Flows as indicated by an imaginary arrow in FIG. 5A, and is filled in the entire cavity 43.

At this time, the width TA of the portion 24A forming the body portion 24 near the gate 44 is set wider than the portion tA forming the flange portion 26 and the cover portion 27, which are distal ends far from the gate 44. As shown by the imaginary line in FIG. 5A, the molten resin 45 injected from the gate 44 is in a state of being sequentially filled from the upstream side at the portion 24A where the body portion 24 is formed. For this reason, the portion 24A for forming the body portion 24 and the portions 26A and 27A for forming the flange portion 26 and the cover portion 27 are simultaneously in a state where the filling is completed.

That is, since the thickness T of the body portion 24 of the bobbin portion 23 is set to be larger than the thickness t of the flange portion 26 and the cover portion 27, the molten resin 45 injected from the gate 44 causes Is prevented from being filled first, and a trunk portion 24 as an intermediate portion and a flange portion 26 as a distal end portion are prevented.
And the cover portion 27 are simultaneously in a state of completing the filling. Therefore, an unfilled portion does not occur in the trunk portion 24.

As described above, in the present embodiment, when the divided body 21 of the coil bobbin 20 is formed, the flow rate of the molten resin 45 injected from the gate 44 is automatically controlled to an optimum value by adjusting the amount of the throttle by each part. Because
It is possible to prevent an unfilled portion from being generated in the bobbin portion 23.

It should be noted that the present invention is not limited to the above-described embodiment, but may be modified without departing from the scope of the invention.
It goes without saying that various changes are possible.

For example, as shown in FIG. 6, in order to facilitate insertion of the coil bobbin 20 between salient poles 13 projecting from the base 12 of the core 11, the height of the body 24 of the coil bobbin 20 is increased. May be changed on the left and right. That is, one of the body portions 24 is made to be 以上 or more with respect to the axial center dimension L of the core 11 and the other is made to be 、 or less. The long torso 24 and the short torso 24 are set to face each other. As described above, when the length of the body portion 24 of the bobbin portion 23 is increased, an unfilled portion is easily generated. However, even in such a case, the thickness T of the body portion 24 is reduced by the thickness of the flange portion 26 and the cover portion 27. By setting the thickness to be greater than the thickness t, it is possible to reliably prevent the occurrence of unfilled portions.

The thickness of the body of the bobbin is not limited to being constant over the entire length, but may be set to gradually decrease from the base end to the tip end.

[0029]

As described above, according to the present invention,
Since it is possible to prevent an unfilled portion from being generated in the divided body of the coil bobbin, it is possible to prevent a short circuit between the coil wire wound around the coil bobbin and the core from occurring.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an armature of a thin motor according to an embodiment of the present invention.

FIG. 2 is a partially omitted plan sectional view.

FIG. 3 is an exploded perspective view showing a main part in an enlarged manner.

4A and 4B show a method of forming a divided body of a coil bobbin, wherein FIG. 4A is a front sectional view of a main part, and FIG. 4B is a plan sectional view.

5A and 5B show a state after the molding, and FIG. 5A is a partial perspective view including a flow of a resin, and FIG. 5B is a partial plan view.

FIG. 6 is an exploded perspective view showing an enlarged main part of an armature of a thin motor according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft, 2 ... Commutator, 3, 4 ... Bearing, 10 ... Armature of a thin motor, 11 ... Core, 12 ... Base, 1
3 salient pole part, 14 head part, 15 shaft hole, 20 coil bobbin, 21 divided body, 22 ring part, 23 bobbin part, 24 body part, 25 projecting piece, 26 flange part , 27 ... cover part, 30 ... coil wire, 40 ... molding die, 41 ... upper die, 42 ... lower die, 43 ... cavity, 44 ... gate,
45 ... Molten resin.

Continued on the front page (72) Inventor Hironobu Kishi 1-2681, Hirosawa-cho, Kiryu-shi, Gunma Co., Ltd. Inside Mitsuba Co., Ltd. (72) Inventor Toshihiro Niki 1-2681, Hirosawa-cho, Kiryu-shi, Gunma Co., Ltd. 5H604 AA05 BB01 BB07 BB14 CC02 CC05 CC15 DB02 PB03

Claims (3)

[Claims] 1. A core having a plurality of salient poles radially protruding from an outer periphery of a base formed in a disk shape, and a coil bobbin covered with the core and wound with a coil wire. The coil bobbin is configured by opposing a pair of divided bodies formed into a shape divided into two in the axial direction of the core, and the divided bodies include a ring portion covering the base of the core and a ring portion of the ring portion. In the armature of a motor having a plurality of bobbin portions radially protruding on the outer periphery and covering each salient pole portion of the core, the coil wire rod in the bobbin portion of the coil bobbin divided body is wound. An armature for a motor, wherein a thickness of a body portion is set to be larger than a thickness of a flange portion for pressing the coil wire from the outside. 2. The motor armature according to claim 1, wherein the thickness of the body of the bobbin is set to be constant from the base end to the tip end. 3. The armature of a motor according to claim 1, wherein the thickness of the body portion of the bobbin portion is set so as to gradually decrease from a base end to a tip end.