JPS6236458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a small permanent magnet-excited starter for use in motorcycles, etc., and particularly to a magnet holding structure thereof.

Conventionally, this type of device has a yoke 1 as shown in Figure 1.
However, since the ferrite magnet 3 is hard and brittle, it has disadvantages such as corners etc. cracking during the adhesion, assembly and transportation processes. Note that 4 in the figure is a rotor. Furthermore, as magnets have become smaller and more powerful in recent years, they have become more energetic, and as a result, their impact resistance has deteriorated (they have become more brittle), and the operating conditions for generators and motors have become more severe, making them difficult to operate in locations with large temperature changes. It has the disadvantage that it cracks when used, as if the magnet were to peel off. This cracking or peeling of the magnet deteriorates the output characteristics, and also has the drawback that it is stuck by the magnetic force on the magnet surface and gets caught between the magnet and the rotor, causing a lock.

The present applicant previously filed Japanese Patent Application No. 54-60375 (Japanese Unexamined Patent Publication No. 55
-153258) and Japanese Patent Application No. 138758 (1983)
No. 55-155567) proposed a method for eliminating the drawbacks of the conventional method, and the present invention is a further improvement to these improved methods.

In general, starters for motorcycles are mounted exposed on the front of the engine, so they are exposed to high and low temperatures, as well as severe vibrations and impacts from stone chips, and are used under extremely harsh conditions.
In principle, the present invention provides a structure that can cope with these severe conditions without using adhesives as in the above-mentioned improved proposal.

An example of a permanent magnet excited starter to which the present invention is applied will be explained with reference to FIG. 2 and subsequent figures. In the figure, 1 is a yoke, 3 is a magnet, and 5 is an aluminum magnet cover.

The magnetic cover 5 is as shown in FIG. 4A.
It has a cylindrical shape having a bottom part 51, a cylindrical part 52, a continuous part 53, and a skirt part 54, and is made of a thin plate of aluminum. The outer diameter dimensions of the cylindrical portion 52 and the skirt portion 54 are set to values larger than the inner diameter dimensions of each magnet 3 and the inner diameter dimension of the yoke 1.
Furthermore, the magnetic cover 5 has a bottom portion 51 and a continuous portion 53.
Because of this, it is rigid and has the function of firmly fixing the magnet 3 inside the yoke 1. Furthermore, since the magnetic cover 5 is made of a non-magnetic material, there is no magnetic loss.

The magnet 3 is a ferrite magnet, and as shown in FIG. 3, the outer circumferential edge 3a of the inner circumferential surface of the magnet facing the rotor is chamfered, and the magnet is fitted with a positioning projection protruding from the inner surface of the yoke 1. Part 3b
Four arcuate segmented magnets are used in this example. The cross-sectional shape of the chamfer 3a of the magnet 3 can have various shapes as shown in FIGS. 3B and C.
This has the effect of facilitating the formation of an overhang in the direction of the yoke. In this embodiment, two fitting parts 3b of the magnets 3 are provided, and positioning protrusions on the inner surface of the yoke 1 are provided correspondingly to each part, but the fitting parts 3b of adjacent magnets 3 are made to be common. There may be half the number of protrusions, or one 3b itself may be provided in the center of each magnet 3, with a corresponding positioning protrusion provided thereon.

The completed shape of the present invention is as shown in FIGS. 2A and B. During the manufacturing process, an elastic body such as urethane rubber was attached to the tip of the upper punch of the manufacturing device, and as a result of pressing through this, the magnet 3 The fitting portion 3b of the magnet 3 reliably engages with the inner surface protrusion 1a of the yoke 1, and the magnetic cover 5 has a first bonding portion 5a with the inner surface of the magnet 3, a second bonding portion 5b with the end surface of the magnet 3,
A third joint portion 5c with the yoke 1, a second U-shaped overhang portion 5d between the bottom and the edge of the magnet 3 in the yoke direction, and a first overhang portion between the magnets 3 in the yoke direction. The portion 5e is formed from a bottom portion 51, a cylindrical portion 52, a connecting portion 53, and a skirt portion 54, respectively, and firmly and reliably fixes the magnet 3 to the yoke 1 without using adhesive. In this case, since the height of the inner surface protrusion 1a is formed larger than the depth of the fitting part 3b, FIG.
The protrusion 1a comes into contact with the magnetic cover 5 as shown in FIG.

Furthermore, if necessary, it is also possible to drip adhesive from above FIG. 2A, thereby making the fixation even more complete. In this case, since the skirt portion of the magnetic cover 5 is press-fitted to form the joint portion 5c with the yoke 1, there is no risk of adhesive leakage.

The permanent magnet excited starter of the present invention has the following effects.

(1) The magnet cover fits tightly to the chamfered part of the magnet, firmly fixing the magnet to the yoke.

(2) The magnet cover is pushed out into the space between the magnets to form an overhang, and firmly fixes the magnets to the yoke.

(3) Since the magnetic cover has a bottom, it does not escape in the inner circumferential direction during press-fitting, and the bottom is swollen by urethane rubber, making its cross section almost U-shaped, increasing the strength of the magnet's fixation.

(4) When the bottom is inflated, the magnet is pushed in the direction of the positioning protrusion of the yoke by the force of the inflation, so it can be fixed correctly at the set position without bending or other problems.

(5) In a drop test, the magnet peeled off and chipped when the magnet without a magnetic cover was placed from a height of 0.5 to 1 m, whereas the product of the present invention was able to withstand a drop of about 3 m.

Next, a manufacturing apparatus as an example of carrying out the present invention will be described with reference to FIGS. 4 and 5.

6 is the upper die of the press, the punch part 6a, the lower plate 6b
The lower plate 6b is guided by the first guide rod 6c against the spring 6d, and the second guide rod 6c guides the lower plate 6b against the spring 6d.
e is also provided. An elastic body 6f made of urethane rubber or the like is provided at the lower end of the punch section 6a, and a magnetic cover 5 is attached to the punch section 6a including the elastic body 6f.
is installed. 6g is a slide piece having a spring and presses and supports the magnetic cover 5.

7 is a lower mold, and 7a is an upper plate which acts as a yoke guide and is supported and guided by a guide rod 7b against a spring 7c. 7d is a stop base having a central hole on the top surface. 7e is a magnet to prevent it from falling, and 7f is a stopper.

Next, a method of using the device of the present invention will be explained.

(1) Place the magnetic cover 5 on the punch part 6a of the upper die 6.
Insert.

(2) Magnetic stopper 7 inside the upper plate 7a of the lower mold 7
Insert four magnets 3 using e.

(3) Align the terminal attachment hole 1b of the yoke 1 with the yoke guide, and fit the lower end 1c of the yoke to the upper surface of the upper plate 7a.

(4) Next, when the press is operated and the pedal is depressed, the upper die is lowered, first the lower edge of the inner hole of the lower plate 6b comes into contact with the yoke upper end 1d, pushing down the yoke 1 and the yoke guide 7a.

(5) At this time, in the upper mold 6, the lower plate 6b is pushed up against the spring 6d using guide rods 6c and 6e as guides, and in the lower mold 7, the yoke guide 7a is pushed downward against the spring 7c. The combined force of both lowers the upper die 6 at an appropriate speed, and the yoke 1 is press-fitted onto the outer periphery of the magnet 3.

(6) The yoke 1 stops descending when the upper surface of the lower plate 6b of the upper mold contacts the lower surface of the fixing plate 6h above it, and the lower surface contacts the upper surface of the stopper 7f of the lower mold.

(7) Furthermore, while the yoke 1 is lowering, the center portion of the punch portion 6a covered with the upper magnetic cover 5 also lowers at the same time, and the cylindrical portion 5 of the magnetic cover 5
2 is press-fitted into the inner periphery of the magnet 3, and at the same time, a portion of the magnet 3 is extended to form an extended portion 5e. Next, the threaded part at the lower end of the punch part 6a descends into the center hole of the stop base 7d, and finally the elastic body 6f in the punch part is compressed and its outer diameter expands, and the cylindrical part 52 of the magnet cover 5 is inserted between the magnets. The magnet 3 is firmly fixed within the yoke 1 by the magnetic cover 5, which extends outward in the radial direction, and the tip 5d of the magnetic cover 5 is expanded in the outer radial direction in a U-shape. In addition, punch part 6
The amount by which a further descends from the position where it contacts the stop table 7d is set to an appropriate amount when manufacturing the mold.

According to the present invention, a magnet cover is attached to the punch part of the press, a magnet is inserted into the upper plate of the lower mold of the press, and the yoke is inserted between the upper and lower molds and operated, so that the magnet automatically closes. The cover is securely fixed to the yoke by the overhang of the cover, and since an elastic material such as urethane rubber is used, the overhang is automatically formed, making it extremely practical.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing an example of a conventional method.
FIGS. 2A and 2B are a partially cutaway front view and a partially cutaway plan view showing an example of a permanent magnet excitation type starter to which the present invention is applied, and FIGS. 3A, B, and C are perspective views of essential parts. and a partially sectional view. Also, Figure 4A,
B is a partially cutaway front view and a bottom view of an upper die of a manufacturing apparatus showing an example of the embodiment of the present invention, and FIGS. 5A and 5B are a plan view and a partially cutaway front view of the lower die. The symbols in the drawings indicate the following members, respectively. 1:
Yoke, 1a: Inner protrusion, 1b: Terminal mounting hole, 1c: Lower end of yoke, 1d: Upper end of yoke, 2:
Adhesive, 3: Magnet, 3a: Chamfered portion, 3
b: Fitting part, 4: Rotor, 5: Magnetic cover, 5a to 5c: Joining part, 51: Bottom part, 52: Cylindrical part, 53: Connecting part, 54: Skirt part, 5d:
U-shaped overhang, 5e: Overhang, 6: Upper mold, 6
a: Punch part, 6b: Lower plate, 6c: First guide rod,
6d: Spring, 6e: Second guide rod, 6f: Elastic body, 6g: Slide piece, 6h: Fixed plate, 7: Lower mold, 7a: Upper plate, 7b: Guide rod, 7c: Spring, 7d: Stop base, 7e: Magnetic fall prevention, 7f: Stopper.

Claims (1)

[Scope of Claims] 1. A cylindrical yoke with both ends open, a plurality of magnets that engage with protrusions formed on the inner surface of the yoke and have chamfered outer peripheral edges of the inner peripheral surface, and inner peripheries of these magnets. A first joint part that comes into close contact with the surface, a first overhang part formed between the magnet, a second joint part that engages with the protrusion of the yoke, a third joint part that comes into close contact with the inner periphery of the yoke, and the shaft of the magnet. In a method of manufacturing a permanent magnet excitation type starter, etc., which includes a cylindrical magnetic cover having a U-shaped second projecting portion formed at a directional end, a magnet is engaged with a protrusion of the yoke from one end of the yoke. At the same time, press fit the magnetic cover having the bottom cylindrical connecting part skirt part from the other end of the yoke and insert it into the first part.
After forming the joining part, the second joining part, the third joining part, and the first overhanging part, the elastic body disposed on the inner periphery of the bottom side of the magnetic cover is compressed to form a U on the bottom side cylindrical part.
A method of manufacturing a permanent magnet excitation type starter, etc., characterized by forming a second protruding portion in the shape of a letter. 2 Cover and support the punch part of the upper mold with a magnetic cover, support the magnet on the inner surface of the upper plate of the lower mold, insert a yoke between the lower plate of the upper mold and the upper plate of the lower mold, and press. 2. A method of manufacturing a permanent magnet-excited starter as set forth in claim 1, wherein the magnet is inserted into the yoke by actuation, and the magnet cover is press-fitted at the same time. 3. The method of manufacturing a permanent magnet excited starter, etc. according to claim 1 or 2, wherein the elastic body is urethane attached to the punch portion of the upper die. 4. A cylindrical yoke with both ends open, a plurality of magnets that engage with protrusions formed on the inner surface of the yoke and have chamfered outer peripheral edges of the inner peripheral surface, and magnets that are in close contact with the inner peripheral surfaces of these magnets. A first joint part formed between the first joint part and the magnet, a second joint part that engages with the protrusion of the yoke, a third joint part that closely contacts the inner periphery of the yoke, and a third joint part formed at the axial end of the magnet. In manufacturing equipment such as a permanent magnet excitation type starter equipped with a cylindrical magnetic cover having a U-shaped second overhang, the upper end of the yoke is locked under the pressure of a spring at the periphery of the central hole. an upper mold that supports the lower plate and the magnetic cover with their bottoms downward and has a punch portion having an elastic body at the tip;
It has an upper plate that locks the lower end of the yoke under the pressure of a spring at the periphery of the central hole where the inner circumferential surface that supports the magnet is located, and a lower mold that has a stop in the central hole. Due to relative movement with
A manufacturing device for a permanent magnet-excited starter, etc., characterized by inserting a magnet from one end of a yoke and simultaneously press-fitting a magnetic cover from the other end. 5. Manufacture of a permanent magnet-excited starter, etc. according to claim 4, characterized in that a magnetic cover can be supported by attaching a spring-pressing slide piece to a part of the punch portion of the upper mold. Device. 6. A manufacturing device for a permanent magnet excitation type starter, etc. according to claim 4 or 5, characterized in that a guide for a terminal mounting hole is attached to the upper plate of the lower mold. 7. A manufacturing device for a permanent magnet excitation type starter, etc. according to claims 4 to 6, characterized in that a magnetic anti-falling device is attached to the inner surface of the upper plate of the lower mold. 8. Claims 4 to 7, characterized in that the upper mold is provided with a fixing plate against which the upper surface of the lower plate contacts, and the lower mold is provided with a stopper against which the lower surface of the upper plate contacts.
Manufacturing equipment for permanent magnet excitation type starters, etc., as described in 2.