JPH041455Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Scope of the Invention] This invention relates to a magnetic flux responsive multi-gap head for detecting the magnetization pattern of a magnetic scale and converting it into an electrical signal.

[Technical background of the invention]

The magnetic flux responsive multi-gear head has been developed and put into practical use in order to obtain high accuracy, high resolution, and stable high output when detecting the magnetization pattern on the magnetic scale and electrically reading the length and angle. n heads are arranged with a gap of λm/2 (λm is the characteristic wavelength of the multi-gap head), and all are connected in series with adjacent heads facing in opposite directions. The outputs of each head are then added together, and when the characteristic wavelength λm of the multi-gap head matches the wavelength λ of the magnetic scale, the output reaches its maximum, and the output is n times that of a single head. It is becoming possible to obtain Conversely, if the wavelength λ of the magnetic scale and the characteristic wavelength of the multi-gap head do not match, a phase difference will occur in the output of each head and the output will be attenuated.

As shown in Fig. 2, such a magnetic flux responsive multi-geap head conventionally has a core made of thin plates a, c, and e made of a high magnetic permeability material (e.g. permalloy), and a core made of a non-magnetic material (e.g. beryllium copper). The thin plates b and d were stacked alternately as separators, and each core had one gap. The gap spacing is as small as 0.1 mm, for example, and variations in this gap have a large effect on the characteristic wavelength of the multi-gap head. The thickness of the thin plates b and d of non-magnetic material are defined within a certain range, and the gap distance is maintained by laminating them.

For example, if the gap spacing mentioned above is set to 0.1 mm, thin plate a of high magnetic permeability material (permalloy),
The thicknesses of thin plates b, d made of non-magnetic material (beryllium copper) and c and e must be precisely defined to 0.05 mm to form a magnetic gap. Furthermore, when laminating the layers, it is necessary to pay attention to variations in thickness, and the thickness must be precisely controlled for two types of materials: high magnetic permeability material and non-magnetic material, which requires a lot of effort and careful attention. This has become a bottleneck in producing a magnetic flux responsive multi-gear head.

[Purpose of the invention] This invention was made based on the actual situation of magnetism, and its purpose is to use high magnetic permeability materials and materials that require strict thickness regulations for the core of multi-gap heads. Among the thin plates of non-magnetic materials, the purpose is to construct a multi-gap head using only thin plates of high permeability material and to manage the thickness of the plates by using only one type of material.

[Summary of the idea]

This idea replaces the core of a multi-gap head, which was conventionally made by laminating thin plates of high magnetic permeability material and thin plates of non-magnetic material alternately, into a high-permeability core with a thickness of 1/4λ of the recording wavelength λ of the magnetic scale. It is constructed by laminating only thin plates of magnetic material, that is,
A part of the laminated thin plates of high magnetic permeability material is formed into a shape that increases magnetic resistance, and this is used as a separator instead of the conventional non-magnetic material to create a magnetic flux responsive multi-gap. This constitutes the head.

[Example of idea]

This invention will be explained below based on embodiments shown in the drawings.

In Fig. 1, all the thin plates constituting the magnetic flux responsive multi-gap head are made of a high magnetic permeability material (permalloy) having a thickness of 1/4λ of the recording wavelength λ of the magnetic scale. ) out of the thin plates f, g, h, i, and j, the shapes of thin plates g and i are divided into two at the center so that the magnetic resistance is as large as possible as shown in the figure, and a scale hole is inserted into which the magnetic scale is inserted. 1 is made sufficiently larger than the scale hole 2 of the thin plates f, h, and j, and a semicircular notch is provided in each of the thin plates cut at the center in order to increase the magnetic resistance between the thin plates and the magnetic scale. . The thin plates g and i of high magnetic permeability material (permalloy) formed in such a shape are:
Although it is a high magnetic permeability material, it fully fulfills the role of a spacer in the same way as a conventional thin plate of non-magnetic material.
Gap spacing is maintained.

Therefore, there is no need to accurately control the thickness of two materials, high magnetic permeability material (permalloy) and non-magnetic material (beryllium copper), as in conventional magnetic flux responsive multi-gap heads. It is only necessary to control the plate thickness of the high magnetic permeability material (permalloy), and the shape to increase the magnetic resistance of the high magnetic permeability material (permalloy) can be easily formed using etching technology. It is.

In addition, in conventional magnetic flux responsive multi-geap heads, a high magnetic permeability material (permalloy) and a non-magnetic material (beryllium copper) are laminated, so there is a difference in hardness between the two materials, so there is a difference in hardness during the lamination stage. When pressure is applied, mechanical distortion occurs in a non-magnetic material with low hardness (beryllium copper), but since this idea uses only a high magnetic permeability material (permalloy), pressure can be applied during lamination.

In addition, when a high magnetic permeability material (permalloy) and a non-magnetic material (beryllium copper) are laminated, the high magnetic permeability material (permalloy) and the non-magnetic material (beryllium copper) are layered on the end face A of the head, as shown in Figure 3A. ) appear alternately, so a specially shaped pick-up member 4 having a magnetism collecting portion 3 shown in Fig. 3(b) must be used to extract the signal. However, in this device, the end face A of the head is entirely made of a high magnetic permeability material (permalloy), so a pick-up member 5 of a simple shape without a magnetic collecting part 3 is used as shown in FIG. 3C. This will help you achieve your goal.

[Effect of idea]

As explained above, in the magnetic flux-responsive multi-gear head of this invention, the thin plates used to construct the head are only high magnetic permeability materials, so there is no need to manage two types of plate thickness as in the past. Moreover, since pressure can be applied when laminating the thin plates, it becomes possible to adjust the dimensions after lamination as a head. Furthermore, since this device only laminates thin plates of high magnetic permeability material, the end face of the head is exposed only with high magnetic permeability material, so there is no need to use a specially shaped pick-up member, and winding of the coil is extremely easy. It has the effect of becoming.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an embodiment of this invention;
FIG. 2 is a schematic perspective view showing the head configuration of a conventional magnetic flux responsive multi-geap head, and FIG. 3 is a schematic perspective view showing the state in which a pick-up member is attached to the conventional head and the head of this invention. . a, c, e, f, g, h, i, j... High magnetic permeability material, b, d... Non-magnetic material, 1, 2... Scale hole, 3... Magnetism collecting part, 5... Pick-up parts.

Claims (1)

[Scope of utility model registration request] In a magnetic flux responsive multi-gap head that detects a magnetic pattern formed by magnetically recording a signal of a fixed wavelength on a magnetic medium, the recording wavelength λ of the magnetic scale is
A plurality of thin plates of high magnetic permeability material with a thickness of 1/4λ of λ and thin plates of high magnetic permeability material with the same thickness as this thin plate of high magnetic permeability material but shaped to increase magnetic resistance are alternately used. A magnetic flux-responsive multi-gap head characterized in that the head is composed only of stacked thin plates of high magnetic permeability material.