JPH0666504A - Linear displacement detector - Google Patents

Abstract

(57) [Abstract] [Object] An object of the present invention is to obtain a linear displacement detection device having excellent assembly workability. [Structure] The connector ASSY 6 is formed with first and second storage chambers 20 and 21 having openings in the same direction. The first storage chamber 20 stores and holds the circuit board 4 on which the magnetic detection element 5 is mounted so that the magnetic sensitive surface 5b is orthogonal to the board surface. In the second storage chamber 21, the magnetic sensitive surface 5
A rod-shaped permanent magnet 3 having magnetic pole surfaces at both end surfaces is provided so as to be opposed to the magnetic detection element 5 so that the center of the major axis lies on the extended surface of b, and is movable in the major axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear displacement detecting device for detecting a linear displacement of a permanent magnet as a change in a magnetic flux direction on a magnetically sensitive surface of a magnetic detecting element.

[0002]

2. Description of the Related Art Conventionally, as a linear displacement detecting device of this type, a magnetic pole surface of a permanent magnet and a magnetically sensitive surface of a magnetoresistive element are arranged so as to face each other, and a linear displacement of the permanent magnet is detected by a magnetically sensitive element of the magnetic detecting element. There is one that is detected as a change in resistance value due to a change in a magnetic field passing vertically through a surface (Japanese Utility Model Publication No. 36089/1990). However, there is a problem that the linear displacement range of the permanent magnet that can obtain linear output characteristics is narrow. The present applicant has previously proposed a linear displacement detection device (Japanese Patent Application No. 4-19871) using a ferromagnetic magnetoresistive element in order to solve the above problems.

3 and 4 are respectively Japanese Patent Application No. 4-19.
871 is an exploded perspective view and an exploded sectional view showing a configuration of a conventional linear displacement detection device shown in No. 871, in which 1 is a case of the linear displacement detection device molded with polybutylene terephthalate resin, and 2 is both end faces. Shaft integrally formed with a rod-shaped permanent magnet 3 having a magnetic pole surface of 4
Although not shown, is a circuit board on which a wiring pattern is formed and various electronic components are mounted.

Reference numeral 5 denotes a magnetic detection element. The magnetic detection element 5 is made of, for example, a ferromagnetic magnetoresistive material (for example, NiFe) having a magnetoresistive pattern in which comb-shaped patterns are orthogonal to each other on the surface of a glass substrate. A ferromagnetic magnetoresistive element 5a is formed, and is further mini-molded with an insulating resin into a rectangular parallelepiped shape. The surface of the glass substrate on which the ferromagnetic magnetoresistive element 5a is formed is a magnetic sensitive surface 5b. Further, in the magnetic detection element 5, the magnetic sensitive surface 5b is orthogonal to the substrate surface, and the comb-shaped pattern of the ferromagnetic magnetoresistive element 5a is perpendicular to the circuit board 4 passing through the center of the comb-shaped pattern. Are mounted on the circuit board 4 by lead terminals 5c drawn out from the magnetic detection element 5 so as to be bilaterally symmetrical.

Reference numeral 6 designates a connector AS as a frame molded from polybutylene terephthalate resin.
SY, the connector ASSY6 has a shaft 2
The guide part 7 for slidingly guiding is integrally formed, and
A copper shield box 8 for shielding electromagnetic waves and a terminal 9 for taking out the output of the magnetic detection element 5 are integrated. Reference numeral 10 is a shield plate for sealing the shield box 8, and reference numeral 11 is a spring that is provided between the shaft 2 and the connector ASSY 6 in a contracted manner to restrict the linear displacement operation of the shaft 2.

Here, the assembly of the conventional linear displacement detecting device will be described. First, the circuit board 4 on which the magnetic detection element 5 is mounted is inserted into the shield box 8 integrated with the connector ASSY 6 from the direction A and attached.
After that, the opening of the shield box 8 is sealed with the copper shield plate 10. Then, the connector ASSY 6 is inserted and fixed in the case 1 in a state where the shaft 2 together with the spring 11 is guided and inserted into the guide portion 7 from the B direction and set.

In the linear displacement detection device thus assembled, the shaft 2 in which the rod-shaped permanent magnet 3 is integrated is
The permanent magnet 3 is guided by the guide portion 7 and can be linearly moved in the long axis direction. The permanent magnet 3 faces the magnetic detection element 5 and its long axis lies on the extension surface of the magnetically sensitive surface 5b. There is. Therefore, the magnetic field generated by the permanent magnet 3 crosses the magnetic sensitive surface 5b of the magnetic detection element 5 in parallel.

Next, the operation of the above linear displacement detecting device will be described. The shaft 2 connected to the DUT is
The permanent magnet 3 is linearly displaced in the longitudinal direction of the permanent magnet 3 while being guided by the guide portion 7 of the connector ASSY 6 to slide in association with the displacement of the object to be measured against the biasing force of the spring 11. Therefore, the permanent magnet 3 integrated with the shaft 2 is also linearly displaced in the long axis direction in association with the displacement of the object to be measured. The linear displacement of the permanent magnet 3 changes the direction of the magnetic flux that crosses the surface of the magnetic sensitive surface 5b of the magnetic detection element 5 in parallel, and the ferromagnetic magnetoresistive element changes in accordance with the change in the direction of the magnetic flux that crosses the magnetic sensitive surface 5b. The respective resistance values of the orthogonal comb-teeth patterns forming the magnetic resistance pattern of 5a change, and the voltage corresponding to the linear displacement of the permanent magnet 3 is output to the circuit board 4 via the lead terminal 5c. The output voltage from the magnetic detection element 5 is the circuit board 4
After being amplified by, the signal is output to an external device (not shown) via the terminal 9 and the displacement of the measured object is detected.

At this time, electromagnetic waves from the outside are shielded by the shield box 8 and the shield plate 10 which are provided so as to surround the circuit board 4 on which the magnetic detection element 5 is mounted, and the circuit mounted on the circuit board 4 is shielded. The malfunction of the element is prevented.

[0010]

As described above, in the conventional linear displacement detecting device, the magnetic sensitive surface 5b is orthogonal to the substrate surface, and the comb-teeth pattern of the ferromagnetic magnetoresistive element 5a is a comb-teeth pattern. The magnetic terminals 5 are mounted on the circuit board 4 by the lead terminals 5c so as to be bilaterally symmetric with respect to the plane perpendicular to the circuit board 4 passing through the center of the magnetic field sensor 4. Since they are opposed to each other and their long axis lies on the extension surface of the magnetic sensitive surface 5b, the mounting direction of the circuit board 4 to the connector ASSY6 and the shaft 2
Since it is orthogonal to the assembling direction, there is a problem that the assembly workability is poor.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a linear displacement detection device capable of improving the assembly workability.

[0012]

A linear displacement detecting device according to the present invention has first and second linear displacement detectors having openings in the same direction.
Having a storage chamber formed therein, a circuit board stored and held in the first storage chamber, and a magnetic sensitive surface formed of a ferromagnetic magnetoresistive element formed in a predetermined pattern. The magnetic detection element mounted on the circuit board so as to be orthogonal to the board surface, and facing the magnetic detection element so that the major axis lies on the extension surface of the magnetically sensitive surface, and movable in the major axis direction. It is provided with a rod-shaped permanent magnet having both end faces as magnetic pole faces arranged in the second storage chamber, and a sealing member for sealing the opening of the frame.

[0013]

In the present invention, the magnetic detection element is mounted on the circuit board arranged in the first storage chamber so that the magnetic sensitive surface is orthogonal to the substrate surface, and the rod-shaped permanent magnet is an extended surface of the magnetic sensitive surface. The second storage chamber is disposed in the second storage chamber so as to be movable in the long axis direction so as to face the magnetic detection element so that the center of the long axis is located above, and the first and second storage chambers have opening portions in the same direction. Since the circuit board having the magnetic detection element mounted in the first storage chamber and the permanent magnet mounted in the second storage chamber have the same direction, the linear displacement Assembly workability of the detection device is improved.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. 1 is a cross-sectional view of a linear displacement detection device showing a first embodiment of the present invention. In the figure, the same or corresponding parts as those of the conventional linear displacement detection device shown in FIGS. The description is omitted.

In the figure, reference numeral 20 denotes a first storage chamber formed in the connector ASSY6.
The circuit board 4 on which the magnetic detection element 5 is mounted is housed in. Reference numeral 21 denotes a second storage chamber formed in the connector ASSY 6 so as to have an opening in the same direction as the first storage chamber 20, and the second storage chamber 21 has a guide formed on its inner wall surface. The shaft 7 is slidably accommodated by the portion 7. Reference numeral 22 is a cover as a sealing member for sealing the openings of the first and second storage chambers 20 and 21 formed in the connector ASSY6.

Here, the assembly of the linear displacement detecting device of the first embodiment will be described. First, the magnetic sensitive surface 5b is orthogonal to the surface of the substrate, and the comb-shaped pattern of the ferromagnetic magnetoresistive element 5a passes through the center of the comb-shaped pattern.
So that the pattern shape is symmetrical with respect to the horizontal plane,
The magnetic detection element 5 is mounted on the circuit board 4 by the lead terminal 5c. After that, the circuit board 4 on which the magnetic detection element 5 is mounted is inserted into the first storage chamber 20 from the direction A and attached. Then, the spring 11 is placed in the second storage chamber 21.
At the same time, the shaft 2 is inserted from the direction A using the guide portion 7 as a guide. Further, the cover 22 is attached to seal the openings of the first and second storage chambers 20 and 21.

In the linear displacement detecting device thus assembled, the shaft 2 in which the rod-shaped permanent magnet 3 is integrated is
The permanent magnet 3 can be linearly moved by being slidably guided by the guide portion 7.
Faces the magnetic detection element 5, and its long axis is located on the extension surface of the magnetically sensitive surface 5b. Therefore, the magnetic field generated by the permanent magnet 3 is applied to the magnetic detection element 5 so as to cross the magnetic sensitive surface 5b in parallel. When the permanent magnet 3 is displaced in the long axis direction, the direction of the magnetic flux that crosses the magnetic sensitive surface 5b in parallel changes.

Here, the linear displacement detecting operation of the first embodiment operates in the same manner as the conventional linear displacement detecting device.

According to the above-described first embodiment, the magnetic detection element 5 is mounted on the circuit board 4 arranged in the first storage chamber 20 so that the magnetic sensitive surface 5b is orthogonal to the board surface. The rod-shaped permanent magnet 3 is arranged in the second storage chamber 21 so as to be movable in the long axis direction so as to face the magnetic detection element 5 so that the long axis lies on the extension surface of the magnetic sensitive surface 5b. In addition, since the first and second storage chambers 20 and 21 have openings in the same direction, the circuit board 4 having the magnetic detection element 5 mounted in the first storage chamber 20 can be installed in the same direction. , The assembling direction of the shaft 2 (permanent magnet 3) into the second storage chamber 21 becomes the same direction, and the assembling workability of the linear displacement detecting device is improved.

Example 2. In the first embodiment described above, the ferromagnetic magnetoresistive element 5a of the magnetic detection element 5 is formed of a magnetoresistive pattern in which two comb-shaped patterns are orthogonal to each other, but in the second embodiment, it is shown in FIG. As described above, the ferromagnetic magnetoresistive element 5a is configured by a full-bridge magnetoresistive pattern in which four comb-teeth patterns are orthogonal to each other, and the same effect is obtained. In the magnetic detection element 5 in which the ferromagnetic magnetoresistive element 5a has a full-bridge magnetic resistance pattern, an output voltage twice as high as that in the first embodiment can be obtained.

[0021]

As described above, according to the present invention, the frame in which the first and second storage chambers having the openings in the same direction are formed, and the circuit board stored and held in the first storage chamber are provided. , A magnetic detection element mounted on a circuit board so that the magnetic sensitive surface is formed of a ferromagnetic magnetoresistive element formed in a predetermined pattern, and the magnetic sensitive surface is orthogonal to the substrate surface, and an extension of the magnetic sensitive surface Face the magnetic sensing element so that the long axis lies on the surface,
In addition, since the rod-shaped permanent magnets having both end faces as magnetic pole faces are disposed in the second storage chamber so as to be movable in the long axis direction, and the sealing member for sealing the opening of the frame is provided, the magnetic detection element is provided. It is possible to insert and assemble the circuit board and the permanent magnet, each of which is mounted in the first and second storage chambers, from the same direction, thereby improving the assembly workability.

[Brief description of drawings]

FIG. 1 is a sectional view of a linear displacement detection device showing a first embodiment of the present invention.

FIG. 2 is a plan view of a magnetic detection element in a linear displacement detection device showing a second embodiment of the present invention.

FIG. 3 is an exploded perspective view of a conventional linear displacement detection device.

FIG. 4 is an exploded cross-sectional view of a conventional linear displacement detection device.

[Explanation of symbols]

 3 Permanent Magnet 4 Circuit Board 5 Magnetic Detecting Element 5a Ferromagnetic Magnetoresistive Element 5b Magnetic Sensing Surface 6 Connector ASSY (Frame) 20 First Storage Room 21 Second Storage Room 22 Cover (Sealing Member)

Claims (1)

[Claims] 1. A frame in which first and second storage chambers having openings in the same direction are formed, a circuit board accommodated and held in the first storage chamber, and a frame formed in a predetermined pattern. A magnetic detection element having a magnetic sensitive surface made of a magnetic material magnetoresistive element, the magnetic sensitive element being mounted on the circuit board so that the magnetic sensitive surface is orthogonal to the substrate surface, and a major axis on the extension surface of the magnetic sensitive surface. Of the rod-shaped permanent magnet, which has magnetic pole surfaces at both end faces, is disposed in the second storage chamber so as to face the magnetic detection element and is movable in the long axis direction. A linear displacement detection device, comprising: a sealing member that seals the opening.