JP2003181879A - Mold for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for injection molding in which an outside pole can be pressed to a member for deciding its inner diameter size with a simple constitution. <P>SOLUTION: The mold for injection molding to mold a resin layer 5 on a periphery of the outside pole 1 having combtooth-like shaped parts 1a to 1e and assembled in a motor comprises an inner periphery control member 17 brought into contact with the inner peripheral surface of the combtooth-like parts of the pole to decide the inner peripheral size of the combtooth-like parts, and gates 10a to 10e opened at positions corresponding to a substantially center of the combtooth-like parts to inject a resin material so that the combtooth parts are pressed to the inner periphery control member by pressures of the resin materials to be injected from the gates. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for molding a resin layer around an outer magnetic pole having a comb tooth-shaped portion.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, in a motor having a comb structure, a resin layer 5 is formed between the comb teeth and the outer peripheral portion of an outer magnetic pole 1 having comb teeth 1a to 1e by an injection molding method. Is being done. In this case, when the outer magnetic pole 1 is incorporated in the motor shown in FIG.
It is important to form the resin layer 5 so that the clearance between the outer peripheral portion of the above and the inner peripheral portion of the comb teeth 1a to 1e is strictly maintained.

In order to maintain this clearance, the inner peripheral portions of the comb teeth 1a to 1e are pressed against the shape portion 17 (see FIG. 5) of the mold for determining the inner diameter dimension of the resin layer 5 so that the molten resin can form the comb tooth 1a. It is necessary to prevent entry into the gap between 1e and the shape portion 17 that determines the inner diameter. To this end, as shown in FIG. 5, pressing pins 25a to 25e connected to the slide piece 28 are provided on the injection molding die, and the pressing pins 25 forcibly determine the inner diameter of the comb teeth 1a to 1e. I had to press it.

At this time, the slide piece 28 is positioned by the locking block 29 and held so as not to move due to the injection pressure. When the molding is completed and the molded product is projected outside the mold, the mold is opened to fix the fixed side mold plate 1
Since the locking block 29 provided in 3 comes off,
The slide piece 28 moves in the direction away from the product due to the restoring force of the spring 27, and the pressing pin 25 comes off from the resin layer 5. Next, the ejector sleeve 16 is actuated, and the molded product is projected out of the mold. Press pin 25 is provided on the outer periphery of the molded product.
The holes a to 25e are left behind on the outer peripheral portions of the comb tooth shapes 1a to 1e.

Further, a relief shape 30 is provided on the movable side mold plate 14 so that the terminal portion 4 is not crushed by the mold when the mold is clamped.
The molten resin wraps around the terminal portion 4, and it is necessary to remove the resin in the secondary processing.

[0006]

In order to make the clearance between the comb teeth shapes 1a to 1e of the outer magnetic pole 1 and the magnet 6 constant, the comb teeth shapes 1a to 1e are formed at the time of molding the resin layer on the outer peripheral portion. It is necessary to strongly press against the member 17 that determines the inner diameter dimension. This is because it cannot be guaranteed that the molten resin injected into the mold cavity during injection molding will enter the gap between the comb teeth 1a to 1e and the member 17 that determines the inner diameter dimension, or enter the outer peripheral portion of the comb teeth. .

When the molten resin enters between the comb tooth shapes 1a to 1e and the member 17 for determining the inner diameter, the pressure causes the comb tooth shapes 1a to 1e to be bent to the outer peripheral portion to form a resin layer on the inner side. In the worst case, the comb teeth may be exposed on the outer peripheral portion of the molded product.

Further, when resin enters the inner peripheral portion of the comb tooth,
The clearance with the outer peripheral portion of the magnet 6 varies, and the performance as a motor deteriorates.

In order to eliminate such a state, it is necessary to use the slide piece 28 to press the comb teeth against the piece 17 for forcibly determining the inner diameter, but a slide mechanism is required for the number of comb teeth and the die structure Becomes complicated and it becomes difficult to take many pieces. Naturally, the die cost also becomes high.

Further, when the thickness of the outer magnetic pole 1 is changed, the pressing force becomes insufficient, and the resin sometimes enters the inside of the comb tooth shapes 1a to 1e. Further, when the outer magnetic pole 1 is thick, the pressing pins 25a to 25e are often damaged.

Also, Since the molten resin covers the bobbin terminal portion 4, it is necessary to remove the resin of the terminal portion 4 in a later step.
When removing the resin, there were problems such as wire breakage, bending and disconnection of terminals.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide an injection molding die capable of pressing the outer magnetic pole against a member for determining the inner diameter dimension thereof with a simple structure. Is to provide.

Another object of the present invention is to provide an injection molding die capable of preventing the molten resin from covering the bobbin terminal portion.

[0014]

[Means for Solving the Problems]
In order to achieve the object, an injection molding die according to the present invention is an injection molding die for molding a resin layer around an outer magnetic pole having a comb tooth-shaped portion and incorporated in a motor, An inner peripheral regulating member for contacting an inner peripheral surface of the comb tooth-shaped portion of the outer peripheral magnetic pole to determine an inner peripheral dimension of the comb tooth-shaped portion, and a position corresponding to a substantially central portion of the comb tooth-shaped portion. And a gate for injecting a resin material,
It is characterized in that the comb tooth-shaped portion is pressed against the inner peripheral regulating member by the pressure of the resin material injected from the gate.

Further, in the injection molding die according to the present invention, the outer magnetic pole has an electric terminal, and an elastic member for sandwiching the electric terminal to prevent a resin material from entering the periphery of the electric terminal. Is further provided.

The injection molding die according to the present invention is provided with a fixed side die and a movable side die, and the elasticity is obtained by utilizing the clamping force of the fixed side die and the movable side die. It is characterized in that the electric terminal is sandwiched between members.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below.

The outer magnetic pole 1 to be molded in this embodiment is the same as that shown in FIG. 1 described in the section of the prior art, and the structure of the motor incorporating this outer magnetic pole 1 is also shown in FIG. It is the same as the one.

This embodiment relates to the structure of a mold for accurately molding the resin layer 5 around the outer magnetic pole 1 shown in FIG.

The present embodiment will be described in detail below with reference to FIGS. 1 to 4.

FIG. 1 is a view showing a yoke assembly which is a molding target of this embodiment.

The yoke assembly 50 includes a bobbin 3a made of a resin material, around which the coil 3 is wound, and a comb tooth shape 1a to
Outer magnetic pole 1 having 1e and made of a metallic material such as pure iron
The inner magnetic pole 2 is made of a metal material such as pure iron.

In this case, the inner magnetic pole 2 is firmly fixed to the outer magnetic pole 1 by a method such as welding. The bobbin 3a has
A terminal 4 made of a metallic material for fixing the winding from the coil 3 is held by a method such as press fitting. The resin layer 5 formed by injection molding forms the outer peripheral portion of the motor.

FIG. 2 shows the yoke assembly 50 shown in FIG.
It is a figure which shows the completion state of the motor which incorporated.

In FIG. 2, reference numeral 6 denotes a magnet which is formed in a cylindrical shape and whose outer peripheral surface is divided in the circumferential direction so as to be alternately magnetized to different poles. The shaft 7 is firmly fixed to the magnet 6. Bearings 8 and 9 that rotatably support the shaft 7 are fixed to the inner magnetic pole 2 by a method such as press fitting.

The resin layer 5 is arranged so that the positions of the comb teeth 1a to 1e of the left and right yoke assemblies 50 are in proper positions.
At the same time as the positioning shape is provided, a shape for firmly fixing the left and right yoke assemblies 50 is provided.

FIG. 3 is a sectional view showing the structure of a die for molding the resin layer 5 around the outer magnetic pole 1 shown in FIG. FIG. 4 is a view showing the arrangement of the runner 12 and the gates 10a to 10e in a state where the yoke assembly 50 is inserted in the mold.

In the present embodiment, in order to strongly press the comb tooth shapes 1a to 1e forming the outer magnetic pole 1 against the member 17 which determines the clearance dimension with the outer peripheral portion of the magnet 6, the outer peripheral portions of the comb tooth shapes 1a to 1e are pressed. Gates 10a to 10e for injecting resin for each comb tooth
Is provided. In this case, as the positions of the gates 10a to 10e, the comb tooth shapes 1a to 1e forming the outer magnetic pole 1 are formed.
The vicinity of the central portion of the outer peripheral portion is preferable.

In FIG. 3, a center pin 15 is arranged in a cavity 22 formed in the fixed-side mold plate 13 and the movable-side mold plate 14 of the mold.
The molded product center position is determined by fitting the inner diameter portion of the inner magnetic pole 2 of the yoke assembly 50 to. Further, the position of the outer magnetic pole 1 in the rotational direction is determined by providing a side surface of the comb teeth 1a to 1e and a positioning hole in the outer magnetic pole 1.

The molten resin injected in the mold closed state flows into the runner 12 via the spool 11. As shown in FIG. 4, the runner 12 is formed in a ring shape,
A gate port is provided on the inner wall surface of the cavity 22 so that the gates 10a to 10e are located at positions close to the center of the comb teeth shapes 1a to 1e of the outer magnetic poles. In this case, it may be necessary to change the gate size so that the injection timing does not shift too much.

Reference numeral 16 denotes an ejector sleeve for projecting a molded product out of the mold. 17 Comb tooth shapes 1a to 1
It is an inner diameter determining piece for determining the inner diameter dimension of e, and at the same time, the bobbin 3a is pressed against the outer magnetic pole surface by the end face to prevent molten resin from entering the inner magnetic pole portion 2 during injection.

Reference numeral 19 denotes an elastic body incorporated in the movable side mold plate 14, and 20 denotes an elastic body incorporated in the fixed side mold plate 13.

The elastic members 19 and 20 are installed so as to cover the entire surface of the terminal 4, and are deformed by the mold clamping force so that the molten resin does not enter, and the amount of deformation of the elastic members 19 and 20 is such that the winding is not broken. And set the hardness.

As described above, according to the above-described embodiment, the outer magnetic pole portion, the inner magnetic pole portion, and the coil having the comb-teeth shape are assembled and then inserted into the injection molding die to form the outer magnetic pole outer peripheral portion. In the method of forming the resin layer between the comb teeth, in order to keep the clearance between the inner peripheral surface of the comb teeth and the outer peripheral surface of the magnet constant, prevent the molten resin from entering the comb teeth in the piece that determines the inner diameter of the comb teeth. As a method of strongly pressing, a method was adopted in which a gate port was provided near the center of the outer peripheral portion of each comb tooth, and the comb tooth was strongly pressed against a piece whose inner diameter was determined by molten resin injected from each gate at high pressure and high speed.

As a result, the die structure can be greatly simplified and the die cost can be greatly reduced as compared with the method of pressing the comb teeth against the piece for determining the inner diameter by the slide mechanism or the like.

Further, since there is no slide structure, the number of molded products to be taken can be increased.

Further, even if the thickness of the comb teeth changes, the thickness of the resin layer on the outer peripheral surface of the comb teeth only changes, so that the molten resin does not enter the inner peripheral surface of the comb teeth. Further, since the molten resin flows under high pressure on the outer peripheral portion of the comb tooth, the inner peripheral portion of the comb tooth is pressed against the piece that determines the inner diameter, the piece shape that determines the inner diameter dimension is transferred, and the shape accuracy of the inner peripheral portion improves. Naturally, the clearance between the magnet outer circumference and the comb tooth inner circumference is stable,
The characteristics as a motor are also improved.

Further, since the terminal portion is made of an elastic material and is strongly covered with the mold clamping force so that the molten resin does not enter, it is possible to eliminate the resin removal of the terminal portion in the subsequent process, and it is possible to greatly The cost can be reduced and troubles such as disconnection at the time of resin removal can be eliminated.

[0039]

As described above, according to the present invention,
With a simple structure, the outer magnetic pole can be pressed against the member that determines the inner diameter dimension thereof.

Further, it is possible to prevent the molten resin from covering the bobbin terminal portion.

[Brief description of drawings]

FIG. 1 is a diagram showing a yoke assembly that is a molding target according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a motor incorporating the yoke assembly shown in FIG.

FIG. 3 is a view showing a state in which a yoke assembly is incorporated in a mold.

FIG. 4 is a diagram showing a gate position of the injection molding die according to the embodiment of the present invention.

FIG. 5 is a view showing a conventional injection molding die.

[Explanation of symbols]

1 Outer magnetic pole 1a-1e Comb tooth shape 2 inner magnetic pole 3 coils 3a bobbin 4 terminals 5 resin layers 6 magnets 7 axes 8 bearings 9 bearings 10a-10e gate 11 spools 12 runners 13 Fixed side template 14 Movable side template 15 Center pin 16 ejector sleeve 17 Inner Diameter Texture Piece 18 Ejector pin for spool 19 Movable elastic body 20 Fixed side elastic body 21 Parting line 22 cavities 25 Comb tooth presser pin 26 Outer pieces 27 Slide piece moving spring 28 slide pieces 29 locking blocks 30 terminal escape shape

Claims (3)

[Claims] 1. An injection molding die for molding a resin layer around an outer magnetic pole having a comb tooth-shaped portion and incorporated in a motor, comprising: an inner peripheral surface of the comb tooth-shaped portion of the outer peripheral magnetic pole. An inner peripheral restricting member for contacting and determining the inner peripheral dimension of the comb tooth-shaped portion, and opening at a position corresponding to substantially the central portion of the comb tooth-shaped portion,
A gate for injecting a resin material, wherein the comb-shaped portion is pressed against the inner peripheral regulating member by the pressure of the resin material injected from the gate. Type. 2. The outer magnetic pole has an electric terminal, and further comprises an elastic member for sandwiching the electric terminal and for preventing a resin material from entering the periphery of the electric terminal. The mold for injection molding according to 1. 3. A fixed side die and a movable side die are provided, and the electric terminals are sandwiched between the elastic members by utilizing the clamping force of the fixed side die and the movable side die. The injection molding mold according to claim 2.