JP3439709B2 - Rotation sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor suitable for detecting the rotation state of a compressor of a vehicle air conditioner.

[0002]

2. Description of the Related Art In this type of rotation sensor, a core made of a magnetic metal material is passed through a center hole of a bobbin around which a coil is wound, a magnet plate is arranged at the tip of the core, and these are covered by a non-magnetic material case. There was something. It should be noted that, for example, a semi-circular metal magnetic plate fixed to the rotary shaft of the compressor rotates close to and facing the magnet plate on the tip side of the case, and an electromotive force is generated in the coil according to the rotation speed. is there.

[0003]

However, it should be noted that there is a problem to be solved in that the magnet plate is easily displaced and the electromotive force cannot be stabilized. An object of the present invention is to provide a rotation sensor that can stabilize the position of a magnet plate.

[0004]

[Means for Solving the Problems] As described in the claims.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described, but it is merely an exemplary embodiment adopted based on the present invention, and the present invention is based on matters peculiar to the embodiment. However, the technical scope of the present invention should be determined based on the matters shown in the claims and the matters substantially equivalent to the matters.

In the illustrated embodiment, a core 4 made of a magnetic metal such as iron is passed through a central hole 3 of a bobbin 2 made of an insulating resin around which a coil 1 is wound, and a magnet plate (permanent magnet) is provided at the tip of the core 4. In the rotation sensor in which 5 are arranged and covered with a case 6 made of a non-magnetic material such as aluminum, an elastic body 7 is interposed between the tip surface of the bobbin 2 and the magnet plate 5. The elastic body 7 is, for example, one in which the periphery of an elastic flat plate is bent toward the bobbin 2 side and its tip is in contact with the tip surface of the bobbin 2, and the material thereof is of course a non-magnetic material,
A light magnetic material may be used. Further, a plate plate 8 made of a magnetic metal such as iron is arranged at the rear end of the core 4 so that a higher electromotive force can be obtained. Although the core 4 is passed through the central hole of the plate plate 8, the core 4 may simply be brought into contact with the surface of the plate plate having no hole. The tip of the core 4 is brought into contact with the elastic body 7.

More specifically, the outer end of the bobbin 2 is brought into contact with one end of a connector 9 made of an insulating resin, the case 6 is covered from the magnet plate 5 side, and the connector 9 is caulked and fixed to the middle part 10. There is. Further, the plate plate 8 is inserted and locked from the side surface slit of the collar portion at the rear end of the bobbin 2. Also, a pair of lead wires (not shown) of the coil 1 are electrically connected to terminals 11 and 11 fixed to the rear end of the bobbin 2, respectively, and the terminals 11 and 11 are further connected to the connector 9.
It is electrically connected to the terminals 12, 12. Although not shown, for example, a semi-circular metal magnetic plate fixed to the rotary shaft of the compressor is provided on the tip side of the case 6,
It rotates in close proximity to the magnet plate 5 and generates an electromotive force in the coil 1 according to the rotation speed thereof.

According to this embodiment, since the elastic body 7 is interposed between the tip end surface of the bobbin 2 and the magnet plate 5, the magnet plate 5 can be continuously pushed toward the case 6 with an appropriate pressing force. The forming magnetic field is stabilized and stable electromotive force is obtained. Further, since the elastic body 7 exists between the core 4 and the magnet plate 5, the core 4 is expanded by the vibration when the case 6 is caulked and fixed to the connector 9 or by the influence of ambient vibration and temperature change. There is a very small possibility that the magnet plate 5 will be broken by exerting an excessive contact pressure on the magnet plate 5. Further, the plate plate 8 may be omitted, but in some cases, higher output can be achieved. Since the core 4 is attracted to the elastic body 7 side by the magnetic attraction of the magnet plate 5, the core 4 can be positioned even if its length is slightly shorter than that shown in the figure.

[Brief description of drawings]

FIG. 1 Sectional view

[Explanation of symbols]

1 coil 2 bobbins 3 center hole 4 core 5 magnet plate 6 cases 7 elastic body 8 plate board

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01P 3/488 G01D 5/245

Claims (3)

(57) [Claims] 1. A rotation sensor in which a core made of a metal magnetic material is passed through a center hole of a bobbin around which a coil is wound, a magnet plate is arranged at the tip of the core, and these are covered with a non-magnetic material case. A rotation sensor with an elastic body interposed between the tip surface and the magnet plate. 2. The rotation sensor according to claim 1, wherein the elastic body is formed by bending a periphery of an elastic flat plate toward the bobbin and contacting a tip of the elastic plate with a tip surface of the bobbin. 3. The rotation sensor according to claim 1, wherein a plate plate made of a magnetic metal material is arranged at the rear end of the core.