JPH07114542B2 - Method of manufacturing ring for frequency generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a ring for a frequency generator, which is formed by a so-called disc gate method in which a mold part is formed on the outer periphery of a circular sheet metal.

[Outline of Invention]

The present invention is a method for manufacturing a ring for a frequency generator that is formed by a so-called disc gate method in which a mold portion is formed on the outer periphery of a circular sheet metal, in which a resin is formed on the outer periphery of a circular sheet metal having a curved surface portion on the outer periphery. By forming a notch on the curved surface of the circular plate of resin and cutting the resin from this notch, the state of the cut surface is always uniform, the cutting trace is good, and the cutting trace is good It is possible to manufacture at low cost without the need for processing.

[Conventional technology]

Conventionally, it has been proposed to mold a resin molded product by a disc gate method. This disk gate method is a plastic molding adopted when molding a mold part (4) on the outer periphery of a circular sheet metal (2) provided with a bearing (3) in the center as shown in FIGS. 4 and 5, for example. It is one of the laws. In this disc gate method, for example, a circular sheet metal (2) provided with a bearing (3) is put in an appropriate die and plastic is extruded and molded as shown in FIG. 6, and the disc gate portion (6) is appropriately formed. The ring (1) shown in FIGS. 4 and 5 can be obtained by removing the runner (5) by cutting by any method. In this case, a frequency power generation (FG) ring can be obtained by molding with a synthetic resin containing magnetic material powder and magnetizing the mold part (4).

When the ring (1) is manufactured by using the conventional plastic molding die as described above, the step of cutting the disc gate portion (6) after the molding as shown in FIG. 6 is separately required. And the manufacturing price rises. Also,
In the process of cooling the synthetic resin, the mold part (4) is likely to be cracked or deformed due to the contraction of the runner (5), and the mold part (4) is damaged by the cutting force for cutting the disk gate part (6). Since it is easy, the defective rate of the product increases and the yield decreases.

In order to solve this problem, the present applicant has previously proposed a resin molding die that can be favorably molded (Japanese Patent Laid-Open No. 60-244516).
Issue). This resin molding die is configured with a mechanism for cutting the disc gate portion, which is the joint between the molded product and the runner, when the die is opened, and the die opening and the disc gate portion are cut in the same process. The number of independent manufacturing processes is reduced, and the product yield is improved.

[Problems to be solved by the invention]

However, when cutting with the die having the above-described structure, as shown in FIG. 7, the runner (5) is moved upward (in the direction of arrow A) together with one die to cut with the disc gate portion (6). However, the cutting portion is not uniform and, for example, as shown in FIGS. 8 and 9, it is desirable to cut along the cutting line C, but the burr-like fragments (4a) May partially remain on the mold part (4) side. If this fragment (4a) remains, it is necessary to remove the fragment (4a) after cutting,
There were many manufacturing steps, which was a problem.

In view of such a point, the present invention is to provide a method for manufacturing a ring for a frequency generator, which can be satisfactorily cut at a disc gate portion without leaving burred fragments.

[Means for solving problems]

The method for manufacturing a ring for a frequency generator according to the present invention is, for example, as shown in FIG. 1, curving an outer peripheral end portion of a circular sheet metal toward one surface side over the entire circumference, and magnetic powder is formed on the curved portion. In a method for manufacturing a frequency generator ring in which a resin member containing is molded, and the molded resin member is magnetized, the curved portion of the circular sheet metal arranged in the molding die is covered over the entire circumference. As described above, while the resin member is molded by injecting it into the resin through the runner, at the time of mold opening to remove the mold from the circular sheet metal, the runner is separated from the circular sheet metal and remains on the mold side, so that one surface is A groove for separation is formed in the vicinity of a curved surface formed by bending on the opposite surface.

[Action]

According to the method for manufacturing a ring for a frequency generator of the present invention, the resin (7) is cut by the curved surface portion (2b) of the circular sheet metal (2), so that the cut surface is always in a uniform state.
The cutting trace becomes good, the processing for making the cutting trace good becomes unnecessary, and it can be manufactured at low cost.

〔Example〕

An embodiment of the method of manufacturing the frequency generator ring of the present invention will be described below with reference to FIGS. 1 to 3. This first
In FIGS. 3 to 3, parts corresponding to those in FIGS. 4 to 9 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the resin molded product as the ring for the frequency generator of this example has a mold portion (7) and a runner (8) which are resin molded on the outer periphery (2a) of the circular sheet metal (2). The disc gate part (9) which is the joint part of the circular plate (2)
It is arranged so as to cover the curved surface portion (2b) at the boundary between the outer periphery (2a) and the upper surface (2c). This circular sheet metal (2)
The outer circumference (2a) is bent at a right angle to the lower surface (2d) side over the entire circumference, so the upper surface (2c) and the outer circumference (2
The boundary with a) is the curved surface (2b). The disc gate portion (9) provided on the curved surface portion (2b) is a groove having a V-shaped cross section, and an angle θ formed between the axial direction of the circular sheet metal (2) and the mold portion (7) side of the groove. Is 30 °, for example. The other parts are configured similarly to the resin molded product shown in FIGS. 4 to 9 as a conventional example.

In this example, the runner (8) of the resin molded product thus configured is cut by the disc gate portion (9) in the mold when the mold is opened. That is, by moving the runner (8) upward (in the direction of arrow A in FIG. 1) by the other mold (not shown) while the mold part is held down by one mold (not shown). The stress is concentrated on the disc gate portion (9), which is weak due to the groove shape, and the mold portion (7) and the runner (8) are cut by the disc gate portion (9). Since the disc gate portion (9) is provided so as to cover the curved surface portion (2b) of the circular sheet metal (2), the cutting line between the mold portion (7) and the runner (8) is shown in FIG. As shown, the position is always constant. That is, the cutting line between the mold part (7) and the runner (8) is likely to be the shortest length, and since the circular plate (2) side is the curved surface part (2b), this shortest length is easily determined. It is cut at a certain position. By making the cutting line constant in this way, as shown in FIG. 3, there is no burr-like fragment over the entire circumference of the mold part, and it is not necessary to remove the fragment after cutting. Therefore, the number of working steps is reduced, and the resin molded product can be manufactured at low cost.

The present invention is not limited to the above-described embodiments, and various other configurations can be adopted without departing from the gist of the present invention.

〔The invention's effect〕

According to the method of manufacturing a ring for frequency power generation of the present invention, the runner (8) is cut from the mold part (7) by the curved surface part (2b) of the circular sheet metal (2), so that the state of the cut surface is always maintained. It becomes uniform, the cutting trace becomes good, and the processing for making the cutting trace good becomes unnecessary. Therefore, there are advantages that the number of working steps is reduced and the ring for the frequency generator can be manufactured at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an embodiment of a method of manufacturing a ring for a frequency generator of the present invention, and FIG. 2 is an enlarged main part showing a state after cutting the runner of FIG. Sectional view, FIG. 3 is a plan view showing a state after cutting the runner of FIG. 1, FIG. 4 is a perspective view showing an example of a conventional resin molded product, and FIG. 5 is a VV line of FIG. 6 is a cross-sectional view taken along the line of FIG.
FIG. 7 is the same sectional view as FIG. 7, FIG.
FIG. 8 is an enlarged cross-sectional view of an essential part of the example of FIG. 5, and FIG. 9 is a plan view of the example of FIG. (2) is a circular sheet metal, (2a) is an outer periphery of the circular sheet metal, (2b) is a curved surface portion of the circular sheet metal, (2c) is an upper surface of the circular sheet metal, (7) is a mold portion, (8) is a runner, (9) ) Is a disc gate part.

Claims (1)

[Claims] 1. An outer peripheral end of a circular sheet metal is curved to one surface side over the entire circumference, and a resin member containing magnetic powder is molded in this curved portion, and the molded resin member is attached. In a method of manufacturing a ring for a frequency generator to be magnetized, a resin is injected through a runner so as to cover the curved portion of the circular sheet metal arranged in a molding die over the entire circumference, and the resin member Together with molding, when the mold is opened to remove the mold from the circular sheet metal, so that the runner remains on the mold side away from the circular sheet metal,
A method for manufacturing a ring for a frequency generator, wherein a separation groove is formed in the vicinity of a curved surface formed by the above-mentioned curve on the surface opposite to the one surface.