JP3134563B2 - Non-contact displacement detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact displacement detector, and more particularly to a compact and inexpensive displacement detector which uses a magnetoelectric conversion element and can be suitably used for mounting on a vehicle in a bad environment.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional non-contact type displacement detector (see Japanese Patent Application Laid-Open No. 2-122205) having a rotating shaft 1 which is connected to an object to be measured and rotates according to its displacement. One end of the rotating shaft 1 is inserted into one end of the cylindrical housing 2 in a liquid-tight manner, and permanent magnets 3A and 3B are installed on the end face of the one end, and are opposed to the permanent magnets 3A and 3B. The magneto-electric conversion element 4 is provided, and the output signal of the magneto-electric conversion element 4 which continuously changes according to the magnetic field change of the permanent magnets 3A and 3B rotating integrally with the rotating shaft 2 is output from the magneto-electric conversion element 4 It is obtained via the signal line 5 outside the housing 2.

[0003]

However, the conventional non-contact displacement detector has a problem in linearity.
That is, since the magnetic flux density of the magnetoelectric conversion element portion changes in a sine (cosine) function, there is no linear region in principle, and the deviation increases as the angle approaches the maximum magnetic flux density and the minimum magnetic flux density. There is a problem that the stricter the linearity is, the narrower the usable rotation angle range becomes.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an excellent non-contact type displacement detector having high linearity in a wide rotation angle range.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a magnetoelectric conversion element, which is disposed so as to sandwich the magnetoelectric conversion element in the direction of magnetic sensitivity of the element, and whose magnetization direction is the same as that of the magnetic element. Two permanent magnets that are perpendicular to the magnetic direction and parallel to each other and have opposite directions, a holder on which the permanent magnets are mounted, and an axial direction connected to the holder, the axial direction of which is parallel to the magnetic sensing direction of the magnetoelectric conversion element. and a rotation shaft that rotates in response to the displacement is connected to the object to be measured, between the permanent magnet
And the magneto-electric conversion element is relatively fixed to the rotation of the rotating shaft.

[0006]

Therefore, according to the present invention, the magneto-electric conversion element and the magneto-electric conversion element are disposed so as to sandwich the magneto-electric conversion element and the magnetization directions thereof are perpendicular to the magnetic direction and parallel to each other. Rutotomoni provided a magnetic circuit formed by the two permanent magnets where directions are opposite, the permanent magnetic
The magnetoelectric conversion element is relatively fixed at the end between the stones
Since the can be linearly changed magnetic flux density of the magneto-electric conversion element for relative rotation.

[0007]

FIG. 1 shows the structure of an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a magnetoelectric conversion element, 12 denotes a circuit board, and 13 denotes a circuit board.
A and 13B are permanent magnets arranged so as to sandwich the magneto-electric conversion element 11 in the magnetic sensing direction, 14 is a holder made of a non-magnetic material,
Reference numeral 15 denotes a rotating shaft, and the holder 14 is connected to the rotating shaft 15. The axial direction of the rotating shaft 15 is parallel to the magneto-sensitive direction of the magnetoelectric conversion element 11. Further, the magnetoelectric conversion element 11
Is disposed at an end between the permanent magnets 13A and 13B, and the permanent magnets 13A and 13B are shifted with respect to the axial center of the rotating shaft 15. The magnetoelectric conversion element 11 is fixed with respect to the rotational displacement of the rotating shaft 15. The rotation shaft 15 is connected to the object to be measured. The magnetization directions of the permanent magnets 13A and 13B are parallel and opposite to each other, and are perpendicular to the magnetic sensing direction of the magnetoelectric conversion element 11.

Next, the operation of the above embodiment will be described.
When the rotating shaft 15 rotates in accordance with the displacement of the device under test, the permanent magnets 13A and 13B mounted on the holder 14 connected thereto rotate, so that the magnetic flux density in the magneto-sensitive direction of the magnetoelectric conversion element 11 is increased. Changes. This magnetic flux density is permanent magnet
The magnetoelectric conversion element positioned at the end between the stones 13a and 13b
11 is relatively fixed, so that the magnetic flux density of the relatively rotating magnetoelectric conversion element unit 11 can be changed linearly. And, since it is set so as to linearly change within a rotation angle range of ± 0.5% within the rotation angle range with respect to the rotation displacement of the rotating shaft 15, the rotation displacement of the DUT can be detected from the output voltage.

[0009]

According to the present invention, as is apparent from the above embodiment, a magneto-electric conversion element is disposed so as to sandwich the magneto-electric conversion element in the magnetic sensing direction, and its magnetization direction is the magnetic sensing direction. Two permanent magnets which are perpendicular to each other but parallel to each other but in opposite directions, a holder on which the permanent magnet is mounted, and an axial direction connected to the holder is parallel to a magnetic sensing direction of the magnetoelectric conversion element. And a rotating shaft connected to the object to be measured, and the magnetoelectric conversion device is located at an end between the permanent magnets.
The element is relatively fixed. According to this configuration,
The magneto-electric conversion element is located at the end between the
Because the rotation axis is rotated in conjunction with the rotational displacement of the device under test, the magnetic flux density of the magnetoelectric conversion element changes linearly with high precision, and the displacement of the device under test is accurately detected from the output voltage. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a non-contact displacement detector according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional non-contact displacement detector.

[Explanation of symbols]

 11 Magnetoelectric conversion element 13A, 13B Permanent magnet 14 Holder 15 Rotation axis

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-2914 (JP, A) JP-A-59-109907 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 7/00-7/34 102 G01D 5/00-5/252 G01D 5/39-5/62

Claims (1)

(57) [Claims] 1. A magnetoelectric conversion element, which is disposed so as to sandwich the magnetoelectric conversion element in a magnetic sensing direction thereof, and whose magnetization directions are perpendicular to the magnetic sensing direction, parallel to each other, and opposite in direction. Two permanent magnets, a holder on which the permanent magnets are mounted, and connected to the holder, the axial direction of which is parallel to the magneto-sensitive direction of the magnetoelectric transducer and connected to the object to be measured, and rotates according to the displacement thereof. A rotating shaft, wherein the permanent magnet
A non-contact displacement detector, wherein the magneto-electric conversion element is fixed at an end portion between the rotation axis and the rotation axis of the rotation shaft.