JPH062119U - Rotational displacement detector - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a rotational displacement detecting device for detecting a rotational displacement of a permanent magnet as a change in a magnetic flux direction on a magnetically sensitive surface of a magnetic detection element, and regulates a rotational position of the permanent magnet. hand,
An object of the present invention is to obtain a rotational displacement detection device that reduces an error in each output characteristic measurement and suppresses a magnetic deviation. A rotary shaft 3 is rotatably mounted on a case 2, and an arm 4 is fixed to one end of the rotary shaft 3. A cylindrical permanent magnet is adhesively fixed to the other end of the rotary shaft 3. A claw 11 is provided on the back surface of the case 2.
The claw 11 is provided on the arm 4 when the arm 4 rotates by a predetermined angle.
The rotation shaft 3 by restricting the rotation of the arm 4
Position the rotation reference position of.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotational displacement detection device that detects rotational displacement of a permanent magnet as a change in magnetic flux direction on a magnetically sensitive surface of a magnetic detection element.

[0002]

[Prior art]

 FIG. 2 is a cross-sectional view showing an example of a conventional rotational displacement detecting device. In the figure, reference numeral 1 is a magnetic detecting element, and this magnetic detecting element 1 is formed, for example, on a glass substrate in a magnetoresistive pattern. A magnetoresistive element made of NiFe, which is a ferromagnetic magnetoresistive material, is formed and further molded into a rectangular parallelepiped shape with an insulating resin. The surface of the glass substrate on which the magnetoresistive element is formed is the magnetically sensitive surface 1a. .

Reference numeral 2 is a case of a rotational displacement detection device molded with polybutylene terephthalate resin, 3 is a rotary shaft rotatably disposed in the case 2, and 4 is an arm fixed to one end of the rotary shaft 3. Reference numeral 5 denotes a cylindrical permanent magnet that is fixedly adhered to the other end of the rotary shaft 3 with an adhesive agent 6. Reference numeral 7 is a circuit board on which a wiring pattern is formed and various electronic parts are mounted, although not shown. A magnetic detection element 1 is mounted on the ceramic substrate 7 such that the magnetic sensitive surface 1a is parallel to the substrate surface. Reference numeral 8 is a copper case as an electromagnetic wave shield case which is arranged so as to surround the ceramic substrate 7 on which the magnetic detection element 1 is mounted, and 9 is a terminal for taking out the output of the magnetic detection element 1 via the through capacitor 10.

Here, the ceramic substrate 7 is housed in the case 2 so that the substrate surface is orthogonal to the permanent magnets 5, that is, the magnetic field of the permanent magnets 5 crosses the magnetic sensitive surface 1a of the magnetic detection element 1 in parallel. Is held.

In the conventional rotational displacement detection device configured as described above, the rotation shaft 3 is rotated to set the magnetizing reference position of the permanent magnet 5 so that the magnetic domain direction of the permanent magnet 5 and the magnetizing direction coincide with each other. It is positioned and magnetized. Further, the rotary shaft 3 is rotated to locate the measurement reference position of the output characteristic, and the output characteristic is measured.

Next, the operation of the conventional rotational displacement detection device will be described. For example, the arm 4 rotates in conjunction with the open / close state of a throttle valve (not shown) in the intake pipe that is the fuel flow path of the vehicle. The rotation of the arm 4 is transmitted to the permanent magnet 5 via the rotary shaft 3, and the permanent magnet 5 rotates in conjunction with the rotation of the arm 4. Due to the rotation of the permanent magnet 5, the magnetic flux direction that crosses the magnetic sensitive surface 1a of the magnetic detection element 1 in parallel changes, and the magnetic resistance pattern of the magnetoresistive element changes according to the change in the magnetic flux direction that crosses the magnetic sensitive surface 1a. The resistance value changes and a voltage corresponding to the rotation angle of the permanent magnet 5 is output. The output voltage from the magnetic detection element 1 is amplified and output to an external device (not shown) via the terminal 9 to detect the open / closed state of the throttle valve.

At this time, electromagnetic waves from the outside are shielded by the copper case 8 surrounding the ceramic substrate 7 on which the magnetic detection element 1 is mounted, and malfunction of the circuit elements mounted on the ceramic substrate 8 is prevented. To prevent.

[0008]

[Problems to be solved by the device]

 Since the conventional rotational displacement detection device is configured as described above, the rotary shaft 3 mounted on the case 2 rotates 360 °, which makes it difficult to find the reference position when measuring the output characteristics, and it is difficult to find a reference position for each measurement. When the permanent shaft 5 is magnetized by mounting the rotary shaft 3 to which the permanent magnet 5 is fixed to the case 2, it becomes difficult to find the reference position for the magnetization, and the magnetic domain direction of the permanent magnet 5 is likely to occur. However, there is a problem in that it is difficult to match the magnetizing direction with the magnetizing direction and the magnetizing deviation easily occurs.

The present invention has been made to solve the above-mentioned problems, and positions the rotation reference position of the rotation shaft to reduce the error in each measurement of the output characteristics and to prevent the magnetization deviation. An object of the present invention is to obtain a rotational displacement detection device that can be suppressed.

[0010]

[Means for Solving the Problems]

 The rotational displacement detecting device according to the present invention is provided with a positioning portion for restricting the rotational position of the arm on the back surface of the case.

[0011]

[Action]

 In this invention, when the rotary shaft rotates, the positioning portion provided on the back surface of the case contacts the arm that rotates in conjunction with the rotation of the rotary shaft, restricts the rotation of the arm, and rotates the rotary shaft. Position the reference position.

[0012]

【Example】

 An embodiment of this invention will be described below with reference to the drawings. FIG. 1 is a bottom view of a rotational displacement detecting device showing an embodiment of the present invention. In the figure, the same or corresponding parts as those of the conventional rotational displacement detecting device shown in FIG. Is omitted.

In the figure, reference numeral 11 denotes a claw serving as a positioning portion provided on the bottom surface of the case 2. The claw 11 has an arm 4 fixed to one end of the rotary shaft 3 interlocked with the rotation of the rotary shaft 3. When rotating, when the rotation angle of the rotation shaft 3 reaches a predetermined angle, the rotation shaft 3 comes into contact with the arm 4 and restricts rotation of the arm 4, that is, the rotation shaft 3.

Here, the measurement of the magnetization and the output characteristics in the above embodiment will be described. First, the rotary shaft 3 is attached to the case 2, and the arm 4 is fixed to one end of the rotary shaft 3. Then, while the arm 4 is rotated and brought into contact with the claw 11, the permanent magnet 5 is adhesively fixed to the other end of the rotary shaft 3 so that the direction of the magnetic domain faces a predetermined direction. Therefore, when the arm 4 is rotated and brought into contact with the claw 11, the magnetic domain direction of the permanent magnet 5 is determined. Therefore, magnetization is performed from a predetermined direction with the arm 4 in contact with the claw 11. That is, the magnetic domain direction and the magnetizing direction can be easily matched, and efficient magnetizing can be performed.

Further, after arranging the ceramic substrate 7 on which the magnetic detection element 1 is mounted, the copper case 8 surrounding the ceramic substrate 7, the terminal 9 and the like in the case 2, the arm 4 is rotated to contact the claw 11. The output characteristic is measured and the reference position is measured to measure the output characteristic.

Other operations of the rotational displacement detecting device according to the above-described embodiment operate in the same manner as the conventional rotational displacement detecting device shown in FIG.

[0017]

[Effect of device]

 According to this invention, since the positioning portion that controls the rotation of the arm that rotates in association with the rotation of the rotating shaft is provided on the back surface of the case, the measurement reference position of the output characteristics can be easily positioned, and the measurement characteristics can be easily adjusted for each measurement. It is possible to reduce the measurement error, to easily position the magnetizing reference position of the permanent magnet, to suppress the magnetizing deviation of the permanent magnet, and to obtain the rotational displacement detecting device capable of efficiently magnetizing.

[Brief description of drawings]

FIG. 1 is a bottom view of a rotational displacement detecting device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional rotational displacement detection device.

[Explanation of symbols]

 1 Magnetic Detecting Element 2 Case 3 Rotating Shaft 4 Arm 5 Permanent Magnet 7 Ceramic Board (Circuit Board) 11 Claw (Positioning Section)

Claims (1)

[Scope of utility model registration request] 1. A case, and a rotating shaft rotatably attached to the case and having an arm fixed to one end,
A permanent magnet disposed at the other end of the rotating shaft and a circuit board held by the case and having a magnetic detection element mounted thereon are provided, and a rotation angle of the permanent magnet is set as a magnetic flux change across the magnetic detection element. A rotational displacement detection device for detecting, wherein a positioning portion for restricting a rotational position of the arm is provided on the back surface of the case.