JPS5842706B2 - Manufacturing method of rotor for converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a rotor such as a small step motor used in a converter for an electronic timepiece.

In recent years, rare earth intermetallic compound magnets have been used as magnet materials for converter rotors, but they have a high energy product and good magnetic properties, but because they are intermetallic compounds, they are tough and brittle.

Therefore, the method of fastening the rotor pinion and the magnet is extremely difficult and limited, and the currently adopted method is to fasten the rotor pinion and the magnet through a seat made of a metal material with a relatively large shape. However, since the magnets are prevented from breaking or chipping, the structure is complicated, the number of assembly steps is also long, and the inertia rate of the rotor itself is high.

An increase in the inertia factor of the rotor impairs the starting performance when driving the rotor, and the time required to rotate a certain angle increases, making it necessary to increase the pulse width of the drive current.
This has drawbacks such as affecting the battery life, and in order to electrically adjust the pointers of a watch, it is necessary to rotate the rotor at high speed, but if the inertia rate is large, the correction drive It also has drawbacks such as lower frequency and longer correction time.

In order to eliminate the above drawbacks, a proposal has been made to set the rotor magnet and rotor pinion in a mold, mold the rotor seat using a polymer material, and at the same time integrate the rotor magnet and rotor pinion into one body. However, conventionally, one or more (two to three) sprues for pouring the molding material are provided on the outer periphery of the rotor seat or a part of the upper surface on the outer periphery side.

However, with the above method, if there is only one sprue, in order to make the flow of the molding material uniform and to ensure reliable molding, the thickness of the rotor seat must be increased, that is, it is necessary to provide a wide space for the molding material to flow. Even if the material of the rotor is replaced from metal to a polymer material, the inertia factor of the rotor will hardly decrease, and the above-mentioned drawbacks will not be completely eliminated.

- It is possible to reduce the thickness of the rotor seat by installing two or three power sprues, but since multiple small sprues are provided, mold production is difficult and the mold structure is very difficult. This has the disadvantage that it becomes complicated and increases the cost of the rotor.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a method for manufacturing a converter rotor at low cost and with a small inertia factor.

゛The embodiments of the present invention will be explained below based on the drawings. Figures 1 and 2 are a sectional view and a plan view of the rotor;
is a low kukana, which includes a discarded pinion part 1b with a circular residual part 1a without a tooth pattern on the outer periphery, a pinion part 1c with a tooth pattern on the outer periphery, an upper part 1d, an upper part 1f, a lower handle 1e, and a lower part. 1g, and a shaft portion 1j.

2 is a rare earth intermetallic compound magnet material, for example, SmCo5
3 is a rotor seat made of a polymeric material in which the rotor pinion 1 and the rotor magnet 2 are integrally molded and fastened.
A fastening portion 3a that fastens between the shaft portion 1J of the rotor pinion 1 and the inner circumference of the rotor magnet 2, and protective layers 3b and 3c formed on the upper and lower surfaces of the magnet 2 are integrally molded.

In this structure, since the rotor seat 3 is made of a polymer material, the inertia factor is reduced, but in order to further reduce the inertia factor, the thickness of each of the protective layers 3b and 3c of the rotor seat 3 is reduced, and at the same time, it is necessary to ensure that they are integrally molded. Since the position of the gate is very important in this case, the gate is formed in a ring shape around the shaft outer circumference of the rotor pinion 1.

In addition, the method of supporting force of the magnets when integrally molding is also important in order to prevent the rotor magnet 2 from cracking or chipping due to handling of the rotor during assembly. Partially provided.

Next, referring to FIG. 3, a method for manufacturing the rotor shown in FIGS. 1 and 2 will be explained.

Reference numeral 4 designates a lower cavity, and the lower cavity 4 is provided with a pinion guide hole 4b and a magnet guide hole 4c.
A positioning pin 5 for positioning the rotor pinion 1 in the height direction is fixed in an adjustable manner.

Further, in the magnet guide hole 4c, four fan-shaped convex support portions 4a are provided at 90 degree intervals for positioning the rotor magnet 2 in the height direction and also serving as a support portion.

Reference numeral 6 denotes a gate bushing having a gate 7 which is a hole having a diameter slightly larger than that of the upper layer 1f of the rotor pinion 1.

Next, to explain the molding order, first move the gate bush 6 upward, and with the mold open, set the rotor pinion 1 so that the lower end surface 1h of the pinion portion 1c contacts the upper end surface 5b of the positioning pin 5. do.

At this time, the lower ff1le and lower part 1g of the rotor pinion 1 fit into the hole 5a of the positioning pin 5, and the positioning pin 5 is adjusted so that the upper surface of the disposable pinion part 1b is at the same height as the bottom surface of the magnet guide hole 4c. The height is adjusted, and the gap in the radial direction between the pinion guide hole 4b and the remaining outer peripheral portion 1a is set to be very small so that the molding material does not flow during molding.

Next, insert the rotor magnet 2 into the magnet guide hole 4c.
The height position of the rotor magnet 2 is determined by the rotor magnet 2 coming into contact with the convex support portion 4a, and the outer circumferential direction of the rotor magnet 2 is guided by a magnet guide hole 4c. The gap between the magnet guide hole 4c and the magnet guide hole 4c is very small and is set to prevent molding material from flowing during molding.

After setting the rotor pinion 1 and the rotor magnet 2, when the gate bushing 6 is lowered, the upper surface of the lower cavity 4 and the lower surface of the gate bushing 6 come into contact, completing the fitting of the molds.

At this time, the upper housing 1d and part of the upper layer 1f of the rotor pinion 1 are located inside the gate T of the gate bush 6, so the hot water lower a of the gate 7 has a ring shape, and the magnet guide hole A space 8 is created within 4c by the rotor magnet 2, rotor pinion 1, and gate bush 6.

That is, between the upper surface of the rotor magnet 2 and the lower surface of the gate bushing 6, the inner circumference of the rotor magnet 2 and the shaft portion 1 of the rotor pinion 1.
j, and between the lower surface of rotor magnet 2 and magnet guide section 4.
It is between the bottom surface of a.

Thereafter, the molding material is poured into the ring-shaped hot water lower a from the gate 7 provided in the gate bush 6, and the space 8 is filled with the molding material, and the rotor seat 3 is filled with the molding material.
At the same time as the rotor magnet 2 and rotor pinion 1 were manufactured,
will be integrated.

At this time, the molding material does not flow into the outer periphery of the rotor pinion 1 and into the pinion portion 1c for the reasons described above.

In addition, since the molding material is poured into the magnet guide hole 4c from the ring-shaped hot water lower a, the rotor seat 3
Compared to the case where a sprue is provided for pouring the molding material into other parts of the rotor seat 3, such as the outer periphery or the upper surface, the area of the sprue can be secured relatively large, and the sprue 7a can be formed in the center part of the rotor seat 3. Since they are arranged in a ring shape, uniform pressure is applied to each part of the rotor seat 3, and the flow of the molding material becomes uniform.

Therefore, since there are no locations where the molding material does not easily flow during molding, the thickness of the space 8 through which the molding material flows, that is, the thickness of each part of the rotor seat 3, can be reduced.

Next, move the gate bush 6 upwards and open the mold.
The rotor, in which the rotor magnet 2 is integrally molded on the rotor pinion 1, is pulled upward together with the gate bush 6 because the material inside the gate 7 and the rotor seat 3 are connected.
It will be removed from the lower cavity 4.

In this state, when the molding material inside the gate 7 is pulled by the upper blade, the molding material is cut at the hot water lower part a of the gate 7 where it is connected with the smallest area, and the rotor falls and can be taken out.

As described above, according to the manufacturing method of the present invention, when integrally molding the rotor pinion and the rotor magnet from a polymer material, the molding gate is formed in one place and in a ring shape ( Since the gate is a round hole shape), the mold structure and manufacturing are easy, which reduces the cost of the rotor, and the molding conditions are also improved due to the position of the sprue, making it possible to reduce the thickness of the rotor seat. This means that the inertia factor of the rotor can be sufficiently reduced.

Furthermore, since the rotor magnets are partially supported during molding of the rotor, the edges of the rotor are less exposed, and therefore the rotor magnets are less likely to crack or chip when handled during assembly.

With these effects, the rotor has good starting performance and the drive current is small, so it is possible to realize a watch that has a long battery life and a high frequency when driven at high speed.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a plan view of a rotor manufactured by the manufacturing method of the present invention, and FIG. 3 is a sectional view of a mold for explaining the molding sequence. 1... Rotor pinion, 2... Rotor magnet, 3... Rotor seat, 4... Lower cavity, 5... Positioning pin , 6...
・Gate Bush, 7...Gate, 4a...
...Convex support part, 4b...Dovetail guide hole,
4c...Magnet guide hole.

Claims (1)

[Claims] 1. In a rotor manufacturing method in which a rotor pinion and a cylindrical rotor magnet made of a rare earth intermetallic compound magnet material are integrally molded from a polymer material, a plurality of protrusion supports for placing the rotor magnet on the bottom surface are provided. a magnet guide hole having a diameter slightly larger than the outer periphery of the rotor magnet; a pinion guide hole having a diameter slightly larger than the pinion portion of the rotor pinion; A mold is used, which is composed of a lower cavity having a positioning pin concentrically with a positioning pin having a recessed lower handle, and a gate bush having a gate slightly larger in diameter than the axis of the rotor pinion. A rotor pinion is inserted into the guide hole so that the lower end surface of the rotor pinion is in contact with and supported by the upper end surface of the positioning pin, and the lower surface of the rotor magnet is in contact with a plurality of protruding support parts in the magnet guide hole. When the rotor pinion is inserted so as to be supported and the gate bushing is lowered, the end of the rotor pinion is housed in the gate of the gate bushing, and a ring shape is formed between the inner periphery of the gate and the outer periphery of the axis of the rotor pinion. By pouring a polymeric material through the gap, the fastening portion filled between the outer circumference of the shaft of the rotor pinion and the inner circumferential surface of the rotor magnet and the protective layer formed on the upper and lower surfaces of the rotor magnet are bonded. 1. A method of manufacturing a rotor for a converter, comprising integrally forming a rotor seat.