JPS5846858A - Formation of magnet ring for bicycle generator - Google Patents

Abstract

PURPOSE:To increase the dimensional accuracy of the titled magnet ring by a method wherein the magnet unit, on which an iron piece was adhered on the external surface of an anisotropic magnet piece, is annularly arranged by providing a plurality of air gaps on the outside of the inner mold, and the outside parts and both side face parts are molded using synthetic resin. CONSTITUTION:The magnet units 3, whereon an iron piece 2 was adhered on the outside of an anisotropic magnet piece 1, is contacted to a round-shaped external surface 5a of the inner mold 5 and, at the same time, a plurality of said magnet units are annularly arranged in the state wherein the prescribed end-part gaps 6 are provided between end parts. Then, a synthetic resin fluid is flow into summer 8 in the outer mold 4 and the resin is flown through sprue 9 into gap 7 located between the roung-shaped inner surface 4a of the outer mold 4 and the magnet unit 3, the gap 6 of each end part, and both side-face parts of each magnet unit 3. Then, the magnet ring requiring no cutting and grinding works which will be performed after molding can be obtained by displacing each magnet unit 3 in accordance with the contraction due to the solidification by the cooling of synthetic resin.

Description

[Detailed Description of the Invention] This relates to the IJ song type method (magnets for power generation equipment attached to The object of the present invention is to form a magnetic L-ring with a power generation capacity comparable to that of a metal magnet (alnico) with high precision without cutting.

The applicant has previously published Utility Model Application No. 51-152886, Utility Model Application No. 51-15502, and Utility Model Application No. 51-IF1887.
As shown in the publication, an anisotropic magnet piece is attached to the inner surface of a non-magnetic hub drum with adhesive. Either fix it in an annular shape, or fix an annular iron core and fix an anisotropic magnet piece to its inner surface by screwing a retaining ring, or protrude an anisotropic magnet piece with an iron piece fixed to its outer surface onto the bottom surface of the non-magnetic hub drum. We devised a method of forming a magnet ring for a bicycle power generator by fixing the magnet ring using a provided protrusion.
Since there is a variation of about 2 m, the inner surface cannot be made into a perfect circle with a predetermined diameter, and therefore cutting and polishing are required, which requires time and effort for molding, resulting in an increase in cost.

In the present invention, apart from the non-magnetic hub drum, an anisotropic magnet piece is arranged in a ring shape in a mold with the ends left open, a synthetic resin is poured into the mold, and the inner surface of the anisotropic magnet piece is placed on the outer surface of the inner mold. They are molded together in the abutting state, and the anisotropic magnet pieces can be displaced according to the contraction of the synthetic resin to form a high-precision anisotropic magnet without cutting or polishing. This eliminates the drawbacks of the conventional method.

Next, the method of the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings. 1 is an anisotropic magnet piece and a magnet unit 3 has an iron piece 2 attached to its outer surface. are arranged in an annular manner within the annular path between the outer mold 4 and the inner mold 5, and the circular outer surface 5 of the inner mold 5
a, and a predetermined end gap 6 is provided between the ends thereof, and a predetermined annular gap 7 is also provided inside the circular inner surface 4α of the outer mold 4. Reference numeral 8 denotes an annular hot water passage within the outer mold, and an injection passage 9 is provided facing each magnet unit 8. This hot water path 8
When the synthetic resin fluid is flowed, the synthetic resin flows into the annular gap 7 from each injection path 9, further enters each end gap 6, and flows into both side surfaces of each magnet unit 8. As this synthetic resin gradually cools and solidifies, it contracts, but each magnet unit 8 can be freely displaced in response to this contraction, so that the outer surface lOα of the solidified magnet ring lO is a predetermined amount larger than the circular inner surface 4α of the outer mold 4. (approximately 1/100 ■), the inner surface loh becomes the same diameter as the outer surface 5α of the inner mold 5, and no distortion occurs inside. Therefore, if the inner surface 4a of the outer mold is made larger in advance by calculating this shrinkage margin, the diameters of the outer surface lOα and the inner surface 1ob of the cooled and solidified magnet ring 10 can be accurately molded into a perfect circle with predetermined dimensions.

Next, attach this magnet ring 10 to the fixed shaft 11 of the bicycle.
The coil 14 fixed to the outer surface of the fixed drum 18 is press-fitted to the inner surface of the non-magnetic hub drum 12' rotatably pivoted to the inner surface of the fixed drum 18, and is fixed to the outer surface of the fixed drum 18.
and fix the fixed drum 1B to the fixed shaft 11.

At this time, the outer surface 1412 of the coil 14 and the magnet ring l
A predetermined slight gap is formed between the inner surface lOb of O,
As the wheels rotate, the non-magnetic hub drum 1z and the magnet ring 1O rotate together, generating electricity in the coil 14. 1
5 is a cover.

According to the present invention, an anisotropic magnet piece is arranged in a ring shape in a mold with its ends separated, the inner surface of the anisotropic magnet piece is brought into contact with the outer surface of the inner mold, and the magnet is molded integrally with synthetic resin. Since the ring is molded, when the magnet ring cools and solidifies, each anisotropic magnet piece can be freely displaced, so no distortion occurs, and no processing is required on the inner or outer diameter of the molded magnet ring. Since it can be made into a perfect circle with high precision, it is easy to mass produce and can be manufactured at low cost. ,

[Brief explanation of the drawing]

FIG. 1 is a front view of an anisotropic magnet piece used in the present invention;
2 is an exploded perspective view of the anisotropic magnet piece shown in FIG. 1, FIG. 8 is a plan view inside the mold during molding, FIG. The figure is number 4
FIG. 6 is a front sectional view of a bicycle power generator using a magnet ring formed by the method of the present invention, and FIG. 7 is a left side view of FIG. 6. l... Anisotropic magnet piece, 2... Iron piece, 8...
Magnet unit, 4...Outer mold, 5...Inner mold, 6
...end gap? ... annular gap, lo... magnet ring. Patent applicant Sho Kumakura Rihito Kodai Sadao Ito Figure 4 Figure 5 Figure 7 Figure 6 Procedural amendment (voluntarily submitted) March 1980, Commissioner of the Japan Patent Office Shima 1) Haruki Tono L case Indication of 1982 Patent Application No. 143407 2 Name of the invention Method for forming a magnetic ring for a bicycle power generator 3 Relationship to the case of the person making the amendment Patent applicant address 2-5-8 Funabori, Edogawa-ku, Tokyo Name
Kumakura Sho Yoshitun Agent d Subject of amendment Specification 1 Contents of amendment Details as stated in the appendix Title of the invention: Magnet ring forming method 2 for general use in rotating single power generators Claims: External surface of anisotropic magnet piece A plurality of magnet units with iron pieces attached to them are arranged in a ring shape in a mold, their inner surfaces are brought into contact with the outer surface of the inner mold, and a predetermined gap is provided between their ends, and then a synthetic resin is poured into the mold. A method for molding a magnet ring for a bicycle power generator, in which the outer surface, the end portions, and both side surfaces of each magnet unit piece are integrally molded. 3. Detailed Description of the Invention This relates to an IJ molding method (for magnets for power generation equipment), and its purpose is to use inexpensive ferrite magnets, which have anisotropy in the radial direction, and to produce high-value materials with high magnetic flux density. The objective is to form a magnet ring with a high power generation capacity comparable to that of a metal magnet (alnico) with high precision without cutting after forming. This author has previously published Utility Model Application No. 51-152886, Utility Model Application No. 51-15502, and Utility Model Application No. 51-152887.
As shown in the publication, an anisotropic magnet piece is fixed to the inner surface of a non-magnetic hub drum in a ring shape with adhesive, or a ring-shaped iron core is fixed, and an anisotropic magnet piece is fixed to the inner surface of the core by screwing a retaining ring. Another idea was to form a magnet ring for a bicycle power generator by fixing an anisotropic magnet piece with an iron piece fixed to the outer surface using a protrusion provided on the bottom of a non-magnetic hub drum. Even after compression molding, firing, and polishing, the magnetic pieces have a variation of about ±0.2 m, so even if they were made into an annular shape, the inner and outer surfaces could not be made perfectly round with the specified diameter, so cutting and polishing were required. The present invention has the disadvantage that it requires many hands for molding and increases the cost.In addition to the non-magnetic Butram, the present invention uses L-oriented magnet pieces arranged in a ring shape with the ends separated in the mold. Then, synthetic resin is poured into the mold, and the anisotropic magnet pieces are molded together with the inner surface in contact with the outer surface of the inner mold, so that the anisotropic magnet pieces can be displaced according to the contraction of the synthetic resin. This method eliminates the conventional defects by molding a high-precision anisotropic magnet ring without cutting or polishing after molding. This will be explained in detail. ■ is an anisotropic magnet piece, and the magnet unit 8 with the iron piece 2 attached to its outer surface is connected to the outer mold 4 and the inner mold 5.
The circular outer surface 5a of the inner mold 5
The outer mold 4
A predetermined annular gap 7 is also provided inside the circular inner surface 4α. Reference numeral 8 denotes an annular hot water passage within the outer mold, and a plurality of injection passages 9 are provided facing each magnet unit 3. When the synthetic resin fluid is flowed through the hot water channels 8, the synthetic resin flows into the annular gap 7 from each injection channel 9, further into each end gap 6, and flows into both side surfaces of each magnet unit 8. As this synthetic resin gradually cools and solidifies, it contracts, but each magnet unit 8 can be freely displaced according to this contraction, so the outer surface 1 (1) of the solidified and molded magnet ring 10
2 is a predetermined amount (approximately 1/10
0 m) shrinkage, and the inner surface lOb shrinks at the same rate as the outer surface than the outer surface 5α of the inner mold 5. Therefore, the outer mold inner surface 4a and the inner mold outer surface 5
If a is increased in advance by calculating this shrinkage margin, the outer surface 10α and inner surface 10 of the cooled and solidified magnet ring IO
The diameter of h can be accurately formed into a perfect circle with a predetermined size. Next, attach this magnet ring 10 to the fixed shaft 11 of the bicycle.
The coil 14 fixed to the outer surface of the fixed drum 18 is integrally pressed into the inner surface of the non-magnetic knob drum 2 which is rotatably pivoted to the inner surface 10 of the magnet ring lO.
6 and fix the fixed drum 18 to the fixed shaft 11. At this time, a predetermined slight gap is formed between the outer surface 1412 of the coil 14 and the inner surface lOh of the magnet ring 10, and the rotation of the wheel causes the non-magnetic knob 12 and the magnet ring lO to rotate together, and the coil Generates electricity on 14th. 15 is cack-. According to the present invention, an anisotropic magnet piece is arranged in a ring shape in a mold with its ends separated, the inner surface of the anisotropic magnet piece is brought into contact with the outer surface of the inner mold, and the magnet ring is formed by integrally molding the anisotropic magnet piece with synthetic resin. Because it is molded, when the magnet ring cools and solidifies, each anisotropic magnet piece can be freely displaced, so no distortion occurs within the molded magnet ring. Since the outer diameter can be made into a perfect circle with high precision without any processing, it is easy to measure and can be manufactured at low cost. 4. Brief description of the drawings Figure 1 is a front view of an anisotropic magnet piece used in the present invention;
FIG. 2 is an exploded perspective view of the anisotropic magnet piece shown in FIG. 1, FIG. 3 is a plan view inside the mold during molding, FIG. The figure is number 4
FIG. 6 is a front sectional view of a bicycle power generator using a magnet ring formed by the method of the present invention, and FIG. 7 is a left side view of FIG. 6. ■... Anisotropic magnet piece, 2... Iron piece, 3...
Magnet unit, 4...Outer mold, 5...Inner mold, 6
... end gap, 7... annular gap, lo... magnet) IJing.

Claims (1)

[Claims] A plurality of magnet units each having a piece of iron attached to the outer surface of an anisotropic magnet piece are arranged in a ring shape in a mold, their inner surfaces are brought into contact with the outer surface of the inner mold, a predetermined gap is created between the ends, and then the magnet units are placed inside the mold. Magnets for bicycle power generators (IJ song type method) in which synthetic resin is poured into the magnet unit and the outer surface, end portions, and both side surfaces of each magnet unit piece are integrally molded.