JPH0557820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a linear stepping motor, and more particularly to a method for manufacturing a small linear stepping motor with improved processing accuracy.

[Conventional technology]

Conventionally, in the manufacturing method of this type of small linear stepping motor, the teeth at the tip of the yoke containing the excitation coil were formed by machining with a grindstone, and the teeth at the tip of the yoke and the comb-like teeth opposite to the teeth at the tip of the yoke were formed by grinding. The base was formed by half-etching, and according to these methods, the processing accuracy was ±10 μm and ±20 μm, respectively. However, as devices become more compact, the positioning accuracy of small linear stepping motors is required to be even higher, and conventional methods are no longer able to satisfy this requirement.

Therefore, by wire electrical discharge machining the teeth at the tip of the yoke having the excitation coil, improvements have been made such that the pitch accuracy of the teeth is less than ±5 μm and the shape accuracy is less than ±1 μm. In addition, the base facing the teeth of this yoke is separated into a thin plate with comb teeth and the base, and the thin plate with comb teeth is formed by full etching to eliminate the comb-like pitch.
It is now possible to form with a precision of 3 μm or less and a shape accuracy of ±0.5 μm or less. Further, by diffusion bonding the thin plate having the comb teeth to the base, it is possible to ensure the bonding.

[Problem that the invention seeks to solve]

In the conventional manufacturing method for linear stepping motors described above, pitch accuracy and shape accuracy can be greatly improved by separating the thin plate with comb teeth from the base and forming the comb teeth by full etching. . However, when diffusion bonding is performed using a thin plate with high-precision comb teeth as a base, there is a drawback that elongation of several tens of micrometers occurs in the pitch direction.
Although it was possible to improve the accuracy of each by separating the thin plate having comb teeth and the base, there is a drawback that the accuracy deteriorates at the stage of diffusion bonding.

An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a method for manufacturing a small linear stepping motor with good positioning accuracy, in which the base and the comb-shaped thin plate are diffusion bonded while maintaining high precision. be.

[Means for solving problems]

A method for manufacturing a linear stepping motor according to the present invention includes: a comb-tooth thin plate facing the teeth of a yoke with a minute gap; and a base stacked on the comb-tooth thin plate; The comb tooth-shaped thin plate and the base are installed between an upper pressing plate and a flat lower pressing plate that are provided along the same line and have small protrusions slightly smaller than the width of the comb teeth, and The small protrusions are positioned so as to be on the comb teeth, and the comb tooth-shaped thin plate and the base are bonded by pressure and heating by the upper pressing plate and the lower pressing plate to bond the comb teeth. It becomes one.

[Effect]

In the diffusion bonding of the comb-like thin plate and the base, the present invention does not press the entire surface to suppress the elongation of the comb-like thin plate, but performs partial pressure-welding with dimensions smaller than the width of the comb teeth of the comb-like thin plate. It is something. For this reason, the comb teeth of the pressure-welded comb-tooth thin plate tend to widen slightly (several μm);
There is no effect on the overall length and pitch dimension.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Figures 1a, b, and c are exploded perspective views of one embodiment of the present invention, Figure 2 is an enlarged perspective view of essential parts of this embodiment, and Figure 3 is an exploded perspective view of an embodiment of the present invention.
Figures a and b are an overall perspective view and an enlarged perspective view of the main parts of a thermocompression bonding jig used for diffusion bonding in this embodiment.

This embodiment has a yoke 1, a permanent magnet 2, an excitation coil 3, a comb-like thin plate 4, a comb-teeth 5, a base 6, and joint parts 9 and 9'. A plate 7, a lower pressing plate 7' and a small protrusion 8 are used.

The teeth at the tip of the yoke 1 are formed by wire electrical discharge machining, and a permanent magnet 2 is fixed to the center thereof. The excitation coil 3 is inserted into the toothed portion of the yoke 1. The comb tooth-like thin plate 4 is a silicon steel plate with a thickness of several tens of micrometers, and the comb teeth 5 are processed by full etching. By processing this comb tooth-shaped thin plate 4 by full etching, it is possible to form the comb teeth 5 with a pitch accuracy of 5 μm or less and a shape accuracy of ±1 μm.
The base 6 is integrated by overlapping the comb-like thin plates 4 and diffusion bonding them. Third
As shown in the figure, there are an upper pressing plate 7 and a lower pressing plate 7' on the upper and lower sides, and a small round protrusion 8 is formed on the upper pressing plate 7.
is formed on the back side. Small protrusion 8 comb teeth 5
The diameter is smaller than the width dimension of the comb teeth 5, but it does not need to be round, and the pitch P in the longitudinal direction of the comb teeth 5 is
Although there is no particular limitation on the size, if it is too large, problems such as floating may occur.

When performing diffusion bonding with this embodiment having such a configuration, the comb tooth-like thin plate 4 and the base 6 are installed so that the comb teeth 5 and the small protrusions 8 are maintained on the same pitch, and the comb teeth are After positioning the shaped thin plate 4 and the base 6, they are sandwiched from above and below between an upper pressing plate 7 and a lower pressing plate 7' for thermocompression, and a pressing force of 2 to 4 kg/
The comb-shaped thin plate 4 and the base 6 are bonded under the following bonding conditions: mm ² , heating temperature of 400 to 700° C., and heating time of 1 to 2 hours.

FIG. 2 shows the state of diffusion bonding according to this embodiment, in which bonded parts 9 and 9' completely bonded by the small protrusions 8 are obtained.

〔Effect of the invention〕

As explained above, in the present invention, the comb-like thin plate and the base can be easily diffusion-bonded by thermocompression bonding using a pressure plate having small protrusions slightly smaller than the width of the comb-teeth of the comb-like thin plate. During bonding, the bonded area on the comb teeth expands slightly (1 μm) in the width direction, but this has the effect of minimizing the effect on pitch errors. In addition, although the non-pressed portions between the bonded portions are not bonded, they do not bulge and are in perfect contact with each other, so that the non-bonded state has no effect on the magnetic circuit at all.

As a result of the measurement, as mentioned above, the spread of the joint is less than 1 μm, and at the same time, the error per pitch is less than submicron, indicating very high precision, so there is no problem in use. As a result, the positioning accuracy according to the present invention was able to be maintained at ±5 μm.

[Brief explanation of drawings]

Figures 1a, b, and c are exploded perspective views of one embodiment of the present invention, Figure 2 is an enlarged perspective view of essential parts of this embodiment, and Figure 3 is an exploded perspective view of an embodiment of the present invention.
Figures a and b are an overall perspective view and an enlarged perspective view of essential parts of a thermocompression bonding jig used for diffusion bonding in this embodiment. 1... Yoke, 2... Permanent magnet, 3... Excitation coil,
4... Comb tooth-like thin plate, 5... Comb teeth, 6... Base, 7
...Upper pressure plate, 7'...Lower pressure plate, 8...Small protrusion,
9, 9'...Joint part.

Claims (1)

[Claims] 1. In a method for manufacturing a linear stepping motor comprising a comb-tooth thin plate facing the teeth of a yoke with a minute gap and a base stacked on the comb-tooth thin plate, a state along the comb teeth of the comb-tooth thin plate is provided. The comb tooth-like thin plate and the base are installed between an upper pressing plate and a flat lower pressing plate, which have small protrusions slightly smaller than the width of the comb teeth; is positioned so that it is on the comb teeth, and the comb tooth-shaped thin plate and the base are integrated by pressurizing and heating by the upper pressing plate and the lower pressing plate and diffusion bonding. A method for manufacturing a linear stepping motor, characterized in that: