JP2505747Y2 - Position sensor-device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type position sensor device for detecting the position of a subject.

[0002]

A pair of cores around which a coil is wound,
A non-contact type position sensor having a spacer that holds the pair of cores at a predetermined interval is, for example,
It is described in Japanese Patent No. 142805. Such a position sensor is housed in a cylindrical case 1 as shown in FIG. 3, and the end face 3 a on the subject side of the core 3 made of a soft magnetic material around which the coil 2 is wound has an opening in the case 1. It is covered with a cover 4 fixed to the. The core 3 is supported by the spacer 5, and the spacer 5 is fixed to the case 1.

In order to protect the core from the impact applied to the cover 4, a gap is provided between the inner surface of the cover 4 and the end surface 3a of the core 3, while the cover 4 is supported only by the circumferential portion of the case 1. Therefore, in order to secure the strength of the cover 4, a member having a certain thickness is used for the cover.

[0004]

In the conventional position sensor, a gap is provided between the end surface of the core and the core cover for the purpose of protecting the core, and a thick plate material is also used for the cover. However, there is a problem in that the sensor internal gap becomes large, that is, the distance between the core end surface and the cover surface becomes large, and the sensor sensitivity decreases. On the other hand, if the thickness of the cover is reduced to increase the sensor sensitivity, there is a risk that the core made of a soft magnetic material will be damaged when an external impact is applied. Therefore, to obtain proper sensor sensitivity,
Substantial gap, that is, the sensor installation problem that the separation distance between the core cover surface (sensor surface) and the subject must be minimized, or the substantial gap is increased to solve this problem. However, there is a cost problem in that the sensitivity of the sensor itself must be increased.

[0005]

The present invention is provided with a pair of cores around which a coil is wound, a spacer for holding the pair of cores at a predetermined interval, a case for accommodating the core and the spacer, and a case provided for this case. In a position sensor device comprising a thin-walled cover for covering the end surface of the core and the spacer on the subject side, the end surface of the spacer is projected to the subject side from the end surface of the core, and the inner surface of the cover is provided. They are in contact with or brought into close proximity.

[0006]

Since the inner surface of the cover covering the end surface of the core on the test side is in contact with or in close proximity to the end surface of the spacer, even if a thin member is used for the cover when external pressure is applied to the cover, Deflection of the inward direction of the sensor is prevented by the spacer, so that the core is not damaged and thus the gap is substantially narrowed.

[0007]

1 and 2, a concave core 1 having coils 12a and 12b on both sides of a U-shaped spacer 15 is shown.
3a and 13b are supported, and the spacer 15 is housed and fixed in a case 11 made of a cylindrical body. Core 13
Ni-Zn ferrite, which has good frequency characteristics and has a good insulating property that does not leak current even when directly wound, is used for a and 13b, and the spacer 15 has a coefficient of thermal expansion equivalent to that of the core. Potassium titanate porcelain is used to reduce the magnetostriction phenomenon. The opening of the case 11 is closed by a cover 14 made of glass-filled epoxy resin to prevent water and dust from entering the sensor. Reference numeral 16 indicates a connecting lead wire for guiding the current of the coils 12a and 12b to the control circuit.

The subject-side end surface 15a of the spacer 15 slightly projects from the subject-side end surface 13c of each of the cores 13a and 13b, and is in contact with or close to the inner surface of the cover 14. Spacer end face 15a with respect to core end face 13c
The amount of protrusion is determined so that the cover 14 does not come into strong contact with the core end surface 13c in consideration of the amount of deflection of the cover 15 toward the inside of the sensor when external pressure is applied to the cover 15 or when the sensor receives an impact. To be Since the core end surface 13c is adjacent to the spacer end surface 15a, the cover 14 does not come into strong contact with the core end surface 13c even if the thickness of the cover 14 is sufficiently small. When the distance is about 15 mm, the protrusion amount of the spacer end surface 15a may be about 0.02 mm. Therefore, the in-sensor gap G can be made sufficiently small.

In the position sensor device of the present invention, when the object to be detected moves in the direction in which the two 13a and 13b are arranged side by side, that is, in the direction of the paper surface in FIG. Since they change in the increasing and decreasing directions, they are extracted as a change in the inductance of the coils 12a and 12b.

[0010]

According to the present invention, since the end surface of the spacer supporting the core is projected from the end surface of the core and the end surface of the spacer is brought into contact with or close to the cover, the distance between the core end surface and the cover surface, that is, The gap in the sensor can be reduced, and therefore, the position where the sensor is arranged with respect to the subject can be made flexible.

[Brief description of drawings]

FIG. 1 is a sectional view of a position sensor device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a position sensor taken out from a case.

FIG. 3 is a sectional view showing an example of a conventional position sensor device.

[Explanation of symbols]

 11 Case 12a, 12b Coil 13a, 13b Core 13c Core end face 14 Cover 15 Spacer 15a Spacer end face

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-259783 (JP, A) JP-A-57-166501 (JP, A) Actually open 1-142805 (JP, U) Actually open-Sho 60- 146869 (JP, U) Actual Kaihei 3-63815 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A pair of cores around which a coil is wound, spacers for holding the pair of cores at a predetermined interval,
In a position sensor device comprising a case for accommodating the core and the spacer, and a thin cover provided on the case and covering end faces of the core and the spacer on the subject side, the end face of the spacer is the end face of the core. The position sensor device is characterized in that the position sensor device is made to project toward the subject side more than the subject and contacted or brought close to the inner surface of the cover.