JPH102757A - Displacement sensor - Google Patents

Abstract

(57) [Problem] To provide a displacement sensor capable of arranging a magnetoelectric conversion element at an appropriate position with respect to a magnet and improving the yield of products. A displacement sensor according to the present invention includes a case (11).
A permanent magnet 3 provided in the case 11 and a Hall element 7 attached to a circuit board 15 provided in the case 11 for detecting a magnetic field change of the permanent magnet 3 accompanying displacement of the magnetic rotating body 10. An adjustment hole 18 for adjusting the position of the Hall element 7 with respect to the permanent magnet 3 was formed in the circuit board 15 with the electric circuit 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement sensor for detecting the number of revolutions of, for example, a gear-shaped magnetic rotating body.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view of a rotation sensor which is a conventional displacement sensor. In a case 1, a permanent magnet 3, an electric circuit 4, and a permanent magnet 3 and an electric circuit 4 are formed using an adhesive. The fixed fixing member 2 is stored. Electric circuit 4
Has a circuit board 5, an electronic component 6 attached to the circuit board 5, and a Hall element 7 which is a magnetoelectric conversion element. The Hall element 7 is arranged such that an axis 7b perpendicular to the sensing surface 7a of the Hall element 7 and a magnetization direction axis 3a of the permanent magnet 3 are parallel to each other. In addition, the electric circuit 4 is connected to the terminal 9 of the connector 30 via the connection body 8.

In this rotation sensor, the rotation of a gear-shaped magnetic rotator 10 which is a magnetic substance provided close to the rotation sensor causes the recess 1 of the magnetic rotator 10 to be formed in the Hall element 7.
0a and the convex portions 10b alternately approach each other, so that the magnetic field from the permanent magnet 3 applied to the Hall element 7 changes, and the Hall element 7 is positive or negative (when the magnetic field lines enter the Hall element 7 from the magnetic rotating body 10 side). A positive magnetic field strength is given when a line of magnetic force enters the Hall element 7 from the side of the permanent magnet 3). This magnetic field strength is detected by the Hall element 7, the detection signal is processed by the electronic component 6, and an output signal corresponding to a change in rotation of the magnetic rotating body 10 is output to the outside through the terminal 9.

FIG. 9 is an explanatory diagram showing a magnetic field in a relationship between the relative positions of the permanent magnet 3 and the Hall element 7 and the positions of the concave portions 10a and the convex portions 10b of the magnetic rotating body 10. When the portion 10b approaches the Hall element 7, when the Hall element 7 is at an appropriate position with respect to the permanent magnet 3, as shown in FIG. When the Hall element 7 comes too close to the magnetic rotator 10 from the proper position with respect to the magnet 3, the Hall element 7 is given a negative magnetic field strength as seen from FIG. Body 1
The approach of the 0 convex portion 10b cannot be accurately detected. Further, for example, when the concave portion 10a of the magnetic rotating body 10 approaches the Hall element 7, if the Hall element 7 is at an appropriate position with respect to the permanent magnet 3, as shown in FIG. When the Hall element 7 is too far from the magnetic rotator 10 relative to the proper position with respect to the permanent magnet 3, a positive magnetic field strength is applied to the Hall element 7 as can be seen from FIG. However, the Hall element 7 cannot accurately detect the approach of the concave portion 10a of the magnetic rotating body 10.

[0005]

In the conventional rotation sensor, the permanent magnet 3 is brought into contact with the stopper 2a of the fixing member 3, and the Hall element 7 is brought into contact with the distal end surface of the fixing member 3, and each of them is made of an adhesive. When the distance between the stopper portion 2a of the molded fixed member 3 and the tip end surface of the fixed member 3 is not a predetermined size, the hole for the permanent magnet 3 is fixed. There is a problem that the position of the element 7 is not appropriate, so that the Hall element 7 cannot accurately detect the approach of the concave portion 10a and the convex portion 10b of the magnetic rotator 10, resulting in a product defect.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and it is possible to obtain a displacement sensor in which a magnetoelectric conversion element can be arranged at an appropriate position with respect to a magnet and the product yield is improved. The purpose is to:

[0007]

A displacement sensor according to the present invention has a circuit board provided with position adjusting means for adjusting the position of a magnetoelectric conversion element with respect to a magnet.

Further, as a position adjusting means, an adjusting hole is formed in the circuit board.

Further, the magneto-electric conversion element is covered with a fixing portion where the adhesive is solidified.

Further, the terminal and the electric circuit are electrically connected by a loosened connection body.

[0011] Further, a projection is formed on the terminal of the connector,
A connecting body is connected to the projection.

Further, a rib is formed on the inner wall surface of the case, and an integrated assembly of an electric circuit, a magnet and a fixing member is fitted into the case.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a sectional view of a rotation sensor according to the present invention.
2 is a bottom view of FIG. 1 with the case of FIG. 1 removed,
3 is a view of the inside of the rotation sensor of FIG. 1 as viewed from an arrow A, FIG. 4 is a partial cross-sectional view of the fixing member and the connector of FIG. 1, and FIG. 5 is a cross-sectional view of a case in an assembly process of the rotation sensor. is there. A permanent magnet 3, an electric circuit 14, and a permanent magnet 3 and an electric circuit 4 are provided with an adhesive in a case 11 in which ribs 12 having a convex cross section extending in the axial direction are formed on the inner wall surface at regular intervals in the circumferential direction. The fixed fixing member 13 is stored. The electric circuit 14 includes a circuit board 15 and the circuit board 1.
5 has an electronic component 6 attached thereto and a Hall element 7 which is a magnetoelectric conversion element. In addition, this Hall element 7
Are arranged such that an axis 7b perpendicular to the sensing surface 7a of the Hall element 7 and a magnetization direction axis 3a of the permanent magnet 3 are parallel to each other. The electric circuit 14 is electrically connected to the terminal 17 of the connector 30 via the connection body 16. The connecting body 16 is made of a strip-shaped thin plate stainless steel having a dimension larger than a distance between the electric circuit 14 and the terminal 17.

The circuit board 15 has two adjusting holes 18 as position adjusting means for adjusting the position of the Hall element 7 with respect to the permanent magnet 3. Further, as shown in FIG. 3, the Hall element 7 is a fixing portion 2 where the adhesive is solidified.
0 covers the sensing surface 7a in an exposed state. In addition, the fixing part 20 is the permanent magnet 3, the end 13 of the fixing member 13.
The adhesive is filled in the space formed by the circuit board 15a and the circuit board 15 and solidified.

On the electric circuit 14 side of the terminal 17, a projection 22 is formed. FIG. 6 is a partial cross-sectional view of a mold when molding the fixing member 13 and the connector 30. The terminal 17 is disposed between the upper mold 23 and the lower mold 24. Has a recess 26 corresponding to the projection 22. Therefore, the protrusion 22 of the terminal 17 is made to coincide with the recess 26 of the lower mold 24, and the pressing member 2
If the fixing member 13 and the connector 30 are molded by injecting a resin into the mold while the terminal 17 of the connector 30 is pressed in step 5, the fixing member 13 and the terminal 17 are integrated in an accurate positional relationship. .

Next, the procedure for assembling the rotation sensor will be described. First, the electric circuit 14 and the magnet 3
Is temporarily fixed using an adhesive. Thereafter, the end of the connection body 16 and the protrusion 22 of the terminal 17 are connected to the space 1 of the fixing member 13.
The terminal 17 and the connection body 16 are connected by performing projection welding by using 9. The space 19 is formed by molding the fixing member 13 by injecting a resin into a mold while the terminal 17 is pressed by the pressing member 25.

Thereafter, before the adhesive is solidified, the concave portions 10a and the convex portions 10b of the magnetic rotator 10 are alternately brought closer to the Hall element 7 by the rotation of the magnetic rotator 10, and the terminals 17 are rotated.
It is checked whether or not the signal output to the outside through is an output signal corresponding to a change in rotation of the magnetic rotating body 10. If the output signal is not correct, while extracting the output signal, the adjustment pin 27 is inserted into the adjustment hole 18 as shown in FIG. Determine the appropriate position for Since the connecting body 16 is made of a deformable thin stainless steel having a dimension larger than the interval between the electric circuit 14 and the terminal 17, the circuit board 15
Is movable without being affected by the terminals 17 connected to the connection body 16.

Next, after the position of the Hall element 7 with respect to the permanent magnet 3 is determined and the electric circuit 14 and the permanent magnet 3 are fixed to the fixing member 13 by solidifying the adhesive, the permanent magnet 3 and the fixing member 13 are fixed. End 13a and circuit board 15
The fixing surface 20a is formed by exposing the sensing surface 7a of the Hall element 7 to the space formed by the above process and filling and solidifying an adhesive. As a result, even if the Hall element 7 is affected by vibration or the like, a reliable relative position between the permanent magnet 3 and the Hall element 7 can be secured.

Thereafter, the electric circuit 14, the permanent magnet 3, and the fixing member 16 to which the electric circuit 14 and the permanent magnet 3 are fixed are provided, and the electric circuit 14, the permanent magnet 3, and the fixing member 16 are integrally assembled into an assembly 31. Is fitted in the case 11. At this time, the permanent magnet 3 and a part of the fixing member 16 are
Is pressed against the ribs 12 on the inner wall surface of the
1 is stored without causing a positional shift. Next, the case 11 and the assembly 31 are completely integrated by heat caulking the distal end portion 32 of the case 11. In the above-described embodiment, the adjustment hole 18 is formed in the circuit board 15 as the position adjustment means. However, the position adjustment means is not limited to this. The protrusion may be formed in advance on the circuit board so as to allow the movement of the projection. Further, in this embodiment, the rotation of the magnetic rotating body 10 is detected as a magnetic body, but the sensor of the present invention can also detect, for example, a reciprocating magnetic body.

[0020]

As described above, according to the displacement sensor of the present invention, since the position adjustment means for adjusting the position of the magneto-electric conversion element with respect to the magnet is provided on the circuit board, the position adjustment of the magneto-electric conversion element with respect to the magnet can be performed. It can be performed easily, the detection accuracy of the displacement of the magnetic body is improved, and the product yield is improved.

Further, by forming the adjustment holes in the circuit board, the position adjusting means can be easily constituted.

Further, since the magneto-electric conversion element is covered by the fixing portion where the adhesive is solidified, it is possible to ensure a reliable relative position between the magnet and the magneto-electric conversion element even if the magneto-electric conversion element is affected by vibration or the like. Can be.

Further, since the terminals and the electric circuit are electrically connected to each other by the loosened connection body, the position of the magneto-electric conversion element can be adjusted without being restricted by the terminals in the assembling process.

Also, a projection is formed on the terminal of the connector,
By connecting the connecting body to this projection, the terminal and the connecting body can be easily connected by projection welding.When the terminal is subjected to insert molding, the projection serves as a relative positioning of the terminal with respect to the fixing member. The terminal is arranged at a predetermined position with respect to the fixing member.

Further, since a rib is formed on the inner wall surface of the case, and an electric circuit, a magnet and a fixing member are fitted into the case in an integrated manner, the assembly does not displace within the case. The case and the assembly are integrated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a bottom view when the case of FIG. 1 is removed.

FIG. 3 is a view of the inside of the case of FIG. 1 as viewed from an arrow A of FIG. 1;

FIG. 4 is a partial sectional view of the fixing member and the connector of FIG. 1;

FIG. 5 is a sectional view of a case in the manufacturing process of FIG. 1;

FIG. 6 is a sectional view of the inside of the mold when the fixing member is molded.

FIG. 7 is a partial cross-sectional view illustrating a state in which an adjustment pin is inserted into an adjustment hole to move a circuit board.

FIG. 8 is a sectional view showing a conventional rotation sensor.

FIG. 9 is a diagram illustrating a positional relationship among a permanent magnet, a Hall element, and a magnetic rotating body, and a magnetic field at that time.

[Explanation of symbols]

3 permanent magnet, 7 Hall element (magnetoelectric conversion element), 10
Magnetic rotating body (magnetic body), 11 cases, 12 ribs,
13 fixing member, 14 electric circuit, 15 circuit board, 1
6 connection body, 17 terminals, 18 adjustment holes (position adjustment means), 20 fixing portions, 22 protrusions, 25 holding members, 27 adjustment pins, 30 connectors, 31 assemblies.

Continued on the front page (72) Inventor Hiroshi Sakanoue 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Wataru Fukui 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (72) Inventor Yutaka Ohashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (6)

[Claims] 1. A case, a magnet provided in the case, a circuit board provided in the case, and a magnetoelectric converter for detecting a magnetic field change of the magnet accompanying displacement of a magnetic body attached to the circuit board. A displacement circuit comprising: an electric circuit having an element; and a position adjusting means for adjusting a position of the magnetoelectric conversion element with respect to the magnet on the circuit board. The position adjusting means is an adjusting hole formed in the circuit board, and the position of the magnetoelectric conversion element with respect to the magnet is adjusted by moving an adjusting pin inserted into the adjusting hole. The displacement sensor according to claim 1. 3. The displacement sensor according to claim 1, wherein the magnetoelectric conversion element is covered by a fixing portion in which the adhesive is solidified. 4. The displacement sensor according to claim 1, wherein the electric circuit is electrically connected to a terminal of the connector via a connection body in a loose state. 5. The displacement sensor according to claim 4, wherein a projection is formed on a terminal of the connector, and the projection is connected to the connecting body. 6. A case in which a rib is formed on an inner wall surface of the case, and an assembly including an electric circuit, a magnet, and a fixing member to which the electric circuit and the magnet are fixed is fitted into the case. The displacement sensor according to any one of claims 1 to 5.