JPS5825022B2 - Structure of flywheel magneto rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a rotor of a flywheel magneto for ignition, lighting, etc., which is an electrical component of an automobile.

Conventionally, there are the following methods for fixing the magnet to the yoke in the rotor of a flywheel magneto, but each method has drawbacks.

(a) Method of assembling magnets using screws, etc.

As shown in FIG. 1, a magnet 3 is inserted between a yoke 1 and a pole piece 2, and the magnets 3 are fastened with screws (or rivets, etc.) 4.

This method requires a large number of assembly steps, and since a ferrite magnet is used, the magnet is easily chipped or broken, and the chips tend to cause accidents such as locking of the rotor.

Therefore, it is necessary to take measures such as attaching a cover 5 on the outer surface of the magnet 3 as necessary.

(b) Method using integral molding, etc. As shown in Figure 2ζ, the magnet 3 is inserted between the yoke 1 and the pole screw 2, tightened with screws 4, etc., and then the resin 6 is filled around the magnet 3. This is the way to do it.

This method requires time to assemble the magnet and mold the resin, and also has problems with the cost and heat resistance of the resin.

In particular, during use at high temperatures, the peripheral wall portion 7 of the resin 6 shown in FIG. 2 becomes dented or cracked.

The object of the present invention is to provide a device capable of eliminating the above-mentioned drawbacks.

The present invention will be described in detail below with reference to the drawings. First, as shown in FIG. A series of circular cuts are made around the entire circumference.

The width of the branch groove 12 is equal to or somewhat larger than the width A of the magnet holder 14, which will be described later, and the depth D is slightly deeper than the plate thickness t of the magnet holder 14.

By the way, the cross-sectional shape of the branch groove 12 may be a simple rectangular shape as shown in FIG.

Next, as shown in FIG. 4 or FIG. 5, a magnetic presser 14 is appropriately created from a thin plate made of non-magnetic metal or synthetic resin.

That is, the magnetic presser 14 shown in FIG. 4 is a rectangular section having a width A, a plate thickness, and an appropriate length B suitable for the magnet used, and the magnetic presser 14 shown in FIG. 4, which has a width A, a plate thickness t, and a length B' equal to the circumference of the groove 12, which It becomes a ring.

The magnet holder 14 has a magnet space 15 for accommodating the magnet 13 as shown in FIGS. 4 and 5.
are appropriately recessed at a depth C1, width E, and length suitable for the magnet 13 used.

That is, in the section-shaped magnet holder 14 shown in FIG. 4, there is one rectangular magnet space 1 in the center.
5 is the flange portion 1T for fitting into the groove 12 and for tightening, which will be described later.
In the band-shaped magnet holder 14 shown in FIG. Align with the poles of the flywheel magneto at equal intervals, leaving the flange 17 for fitting and tightening.
They are installed in each row.

By the way, the magnets 13 housed in each of the magnet spaces 15 are solid molded magnets such as ferrite magnets.

Next, with the magnet 13 accommodated in the groove 12 and the magnet space 15 according to the above structure, the magnet holder 14 is appropriately fitted, and the flange 1 of the magnet holder 14 is fitted.
The magnetic presser 14 is fixed in the groove 12 by crushing and constricting an appropriate part of the groove end 19 forming the branch groove 12 with the magnet holder 7 in contact with the bottom 18 of the groove 12.

Figure 6 shows the section-shaped magnetic presser 14 shown in Figure 4.
In the groove 12 having a rectangular cross section, four magnets are fitted in accordance with the number of poles and the arrangement of the flywheel magnets, in this example, with four poles spaced apart by 90 degrees.
When the groove end portions 19 forming the groove 12 corresponding to the upper and lower left, center, and right ends of 4 are crushed to form respective proofing portions 16, and each magnet presser 14 is individually fixed by the constriction portions 16. It shows.

However, the band-shaped magnetic presser 14 shown in FIG.
Although not shown in the figure, the case where the sixth
Almost the same as the case shown in the figure, the magnet presser 14 is fitted into the groove 12 in an annular shape, and the edges of the groove 12 that correspond to the circumference of each magnet space 15 and between each space is and is are crushed and squeezed to form an integral structure. Fixed to.

The effects of the present invention explained above are as follows.

(1) Since the magnetic presser is made of a thin plate made of a non-magnetic material such as metal or synthetic resin, a shape suitable for the purpose can be obtained.

(2) Since the magnet is housed within the magnet space and covered with a magnet holder, even if a fragile material such as a ferrite magnet is used, a part of it will not be damaged or fall out. Therefore, it is possible to prevent rotor locking accidents caused by these fragments.

(3) Since the structure is such that it can be fixed by simply fitting the magnetic holder into the groove and tightening it by tapping a part of the groove, installation screws, adhesives, etc. can be omitted, reducing costs, and installation can be done using a press. Since only machining is required, the installation time can be shortened compared to screw tightening, adhesive application, etc. Also, since a drying oven is not required, expensive equipment investment for this purpose can be omitted.

(4) Since the magnetic space is embedded in the magnetic presser foot, it can be produced integrally by punching, and its productivity is particularly high.

[Brief explanation of the drawing]

1 and 2 are partial sectional views showing two examples of conventional magnet fixing methods, FIGS. 3 to 7 show embodiments of the present invention, and FIG. 3 is a perspective view of a yoke; Fig. 4 is a perspective view of the section-shaped magnet holder, Fig. 5 is a developed view of the band-shaped magnet holder, Fig. 6 is a partially cutaway front view of the assembled state, and Fig. 7 is a partial cross-section showing the cross-sectional shape of the groove. It is a diagram. In the diagram above, each symbol indicates the following: 1: Yoke, 2: Ball piece, 3: Magnet, 4: Screw, 5: Cover,
6: Resin, 11: Yoke, 12: Groove, 13: Magnet, 14: Magnet holder, 15: Magnet space,
16: Shark part, 11: Flange part, 18: Bottom part, 19: Groove end part.

Claims (1)

[Claims] 1 A non-magnetic material that has a cylindrical shape (made from magnetic material), has a series of grooves sunk all around the inner peripheral surface of the yoke, and has a flange around the periphery to form a magnet space with a U-shaped cross section. A magnet is fitted and accommodated in the magnetic space of a magnetic holder made of a metal oxide, and an appropriate number of the magnetic holders are arranged on the inner periphery of the yoke so that the flange of the magnetic holder comes into contact with the bottom of the groove of the yoke. A rotor structure for a flywheel magneto, characterized in that the ends of the yoke groove forming the groove are constricted at appropriate locations, and the flange of the magnet holder is constricted and fixed between the groove bottom and the constricted portion.