JPS582086A - Manufacture of contactless potentiometer - Google Patents

Abstract

PURPOSE:To manufacture potentiometers of the same characteristic in a large quantity and yet having favorable yield by a method wherein a belt type plate of soft iron is wound around a jig, the belt type plate is cut along the axial line of the jig, and individual magnetic body pieces are adhered to be fixed on rotary shafts of the potentiometers. CONSTITUTION:The belt type plate 21 of soft iron of about 0.1-1mm. thickness is wound for the plural number of turns around the columnar jig 20 having the diameter the same or a little larger than the rotary shaft 2 of the potentiometer applying tension of the fixed value. The belt type plate 21 is cut along the axial line of the jig 20 using a disk type cutter 22. The cut belt type plate 21 is torn into pieces individually in the state wound around the jig 20 for one turn, and the magnetic body pieces 16 of the plural number are manufactured at the same time. Then the magnetic body pieces 16 are removed from the jig 20, and are inserted up to the prescribed positions of the rotary shafts 2 to be adhered and fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a potentiometer using a magnetoresistive element.

A non-contact L tensionmeter using a magnetoresistive element has a permanent magnet piece attached to the tip of the rotating shaft, and the area of the magnetic field that acts on a pair of magnetoresistive elements arranged opposite to each other is adjusted relative to each other as the rotating shaft rotates. A piece of magnetic material of the spiral group is provided around the rotating shaft, and a pair of magnetoresistive elements are placed in the magnetic path in parallel with the rotating shaft in close proximity to this magnetic material piece. There are potentiometers that relatively change the area of the magnetic field that acts on the magnetoresistive element as it rotates.
While the rotation angle of the rotating shaft is suitable for a limited angle range of 180° or less, the latter is suitable for a rotation angle of 180° or more, especially 360°, by setting the pitch of the spiral magnetic material piece at a predetermined ratio.
It is possible to detect the rotational angular position of the rotating shaft over an angular range of up to 100°.

By the way, for the rotating shaft of the latter potentiometer, a spiral convex part is formed by cutting off the side surface with a cutter, or a thin piece of magnetic material is attached to the rotating shaft for each potentiometer. However, in the former case, there is a disadvantage that it is difficult to apply when the If diameter of the rotating shaft is small, which requires precision machining, and in the latter case, it is difficult to apply. During the winding of the magnetic strip, only about 1 portion occurs, and these occur individually differently and are therefore not suitable for a straight line.

The present invention provides (b) a method of manufacturing a non-contact potentiometer that is capable of detecting the degree of rotation over a 180° angle range of the axis of rotation and is suitable for production. .

Examples of the manufacturing method of the present invention will be described in detail below. 1 and 2 schematically show the construction of a contactless potentiometer assembled using the method of the present invention. Non-magnetic materials/
A rotating shaft 2 passing through a cylindrical housing 1 made of plastic or aluminum, for example, is rotatably supported at ends 5 and 6 of the body 1 by two bearings 6.4. . A window 7.8 is provided on the side surface of the housing 1, in one of which a pair of semiconductor magnetoresistive elements 9.10 is inserted into the permanent magnet 1.
It is supported by the base 12 and is attached to one of the magnetic poles (for example, the hemipole) of the magnet 1 with a surface or a thin magnetic material interposed therebetween. The permanent magnet 11 has one magnetic pole surface (N pole) exposed, and the rest is buried in the base 12.

The base 12 is molded from a plastic material into a shape that fits the window 7°8, and is used to determine the position of the magnetic resistance element 9°10 from the axis of rotation, and is fixed to each body 1 with adhesive. be done. Also, the base 12. Terminal pins 13, 14, 15 with protruding sides are embedded in the holder, and magnetoresistive elements 9, 10
The electrodes at both ends are connected to the terminal pins 15, 14, and 15 by lead frames, wires, etc. so that the wires are connected in series. When the magnetoresistive element 9.10 is made as a one-chip element with a three-terminal configuration, both ends and the middle electrode are similarly connected to the terminal pin 13. '14.15.

At a position facing the magnetoresistive element 9.10 of the rotating shaft 2,
A spiral magnetic piece 16 is fixed. The rotating shaft 2 may be made of a magnetic material such as pure iron, piano wire, or a non-magnetic material such as aluminum, brass, or stainless steel (8U8304). In the former case, it acts as part of the magnetic path.

The magnetic piece 16 diagonally crosses the axis of the rotating shaft 2.

That is, when inspecting the angular range of 660° of the rotating shaft 2, the magnetic resistance elements 9 are arranged in a row in the axial direction of the rotating shaft 2.
．． The magnetic flux density change of the magnetic flux passing through 10 is 360° of rotation axis 2.
The width and inclination of the magnetic piece 16 are set so that it moves from one magnetoresistive element to the other as the magnetoresistive element rotates. In addition, when detecting an angular range of 180° of the rotation axis 2, the change in magnetic flux density is such that, for example, the magnetic flux density moves from the magnetoresistive element 9 to the magnetoresistive element 10 as the rotation axis 2 rotates by 180". Constitutes the magnetic piece 16. In short,
When the magnetic piece 16 detects an arbitrary angular range up to 360° of the rotating shaft 2, when the rotating shaft 2 rotates to that angle, the change in magnetic flux density due to the magnetic piece 16 changes from one side to the other. By moving from one magnetoresistive element to the other, the resistance values at both ends of the magnetoresistive elements 9 and 10 may change linearly up to a predetermined angle. In this case, in order to maximize the rate of change in resistance of the magnetoresistive element, it is desirable that the magnetic field region where the magnetic flux density increases is completely switched from one magnetoresistive element to the other magnetoresistive element. However, if the rate of change in resistance can be somewhat low, it does not matter even if the region with high magnetic flux density straddles the magnetoresistive elements on both sides when the rotating shaft 2 rotates at a predetermined angle.

The manufacturing method of the present invention particularly relates to the magnetic piece 16, and as shown in FIG. A belt-shaped plate 21 of soft iron is wound many times while applying a constant tension. The width of the plate 21 is determined by the angular range to be detected as described above, and the inclination of the jig 2IIJ with respect to the axis, that is, the winding pitch is determined by the rotation angle of the rotary shaft 2 as described above.

The strip plate 21 wound around the jig 20 is cut along the axis of the jig 20 using a disk-shaped cutter 22, as shown in FIG. The teeth of the cutter 22 are required to be sufficiently thin. Furthermore, the means for cutting the strip plate 21 is not limited to the above-mentioned method, and it goes without saying that a means such as a laser beam or an electron beam can be used.

The cut strip plates 21 are separated into individual pieces in a manner that they are wound around the jig 2o, and a large number of magnetic pieces 16 are manufactured at once. These magnetic pieces 16 are removed from the jig 20.

As shown in FIG. 5, the individual magnetic pieces 16 are each inserted up to a predetermined position on the rotary shaft 2 of the potentiometer and fixed with adhesive.

A stopper 26 can be provided at a predetermined position on the rotating shaft 2 to determine the insertion position of the magnetic piece 16. If the magnetic piece 16 is inserted to the position of this stopper 26, the position of the magnetic piece 16 on the rotating shaft 2 becomes accurate.

The rotating shaft made as shown in FIG. 5 is incorporated into a potentiometer as shown in FIG.

As mentioned above, according to the present invention, it is possible to make circular and uniform pieces of magnetic material in the same place, and a potentiometer using a rotating shaft to which these pieces of magnetic material are attached produces an output with good linearity. , potentiometers with the same characteristics can be manufactured in small quantities and with high yield.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of a non-contact potentiometer, Fig. 2 is a cross-sectional view of the potentiometer in Fig. 1 taken along the dashed line ■-■, and Figs. 3 and 4 are magnetic materials used in the potentiometer of the present invention. FIG. 5 is an explanatory view showing a method of manufacturing the piece, and is a perspective view of the magnetic piece fitted onto the rotating shaft. In the figure, 1 is the housing, 2 is the rotating shaft, 7.8 is the window, 9°10 is the magnetic resistance element, 11 is the permanent magnet, 12 is the base, 13, 1
4.15 is a terminal bin, 16 is a magnetic piece, 20 is a jig, 2
1 is a strip plate, and 22 is a cutter. Patent Applicant Denki Acoustics Co., Ltd. Sai1 Ward Sai2 Diagram Sai3 Diagram, T4゜Saiso5 Diagram

Claims (1)

[Claims] A rotary shaft is rotatably supported on the body by penetrating the body,
A pair of magnetoresistive elements magnetically biased by a permanent magnet is disposed close to the rotating shaft, and a magnetic piece that relatively changes the density of magnetic flux passing through the magnetoresistive element is attached to the rotating shaft, The magnetic material piece is formed by winding a belt-shaped plate made of soft iron around a cylindrical jig many times, and then cutting the wound belt-shaped plate along the axis of the jig using a cutting means. A method of manufacturing a contactless potentiometer characterized by: