JP2523757Y2 - Rotation sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to a rotation sensor for detecting a rotation speed of a wheel or the like of an automobile or the like.

[Conventional technology]

Conventionally, as such a rotation sensor, for example, a rotation sensor using a magnet as shown in FIG. 2 is known.

That is, in FIG. 2, a rotation sensor 1 has a magnetic material rotating gear 2 mounted on a rotating shaft such as a wheel of an automobile whose rotational speed is to be detected. A pole body 3 made of a magnetic material such as iron, and a magnet 4 arranged to fit into a recess 3a formed in the rear end surface of the pole body 3; And a coil 6 wound around a coil frame 5 fitted around the pole body 3.

In this case, the coil frame 5 is formed so as to cover the magnet 4 integrally with the pole body 3 by resin or the like.
That is, when the coil frame 5 is formed, the front end of the magnet 4 is fixed in the concave portion 3a on the rear end surface of the pole body 3 by press-fitting or the like, and then the pole body 3 and the The magnet 4 is formed integrally with the pole body 3 and the magnet 4 in a state where the magnet 4 is inserted into the plastic molding die. The magnet 4 is provided with a polarity.

When the gear 2 is rotating, the rotation sensor 1 configured as described above moves the gear 2 against the tip of the pole body 3.
Are repeatedly approached and separated from each other, so that the distance from the tip of the pole body 3 to the nearest part of the gear 2 is alternately increased or decreased. As a result, the number of lines of magnetic force passing through the pole body 3 increases or decreases, and the magnetic flux changes. Therefore, an AC voltage is generated in the coil 6 wound around the coil frame 5, and the frequency is changed to the pole body 3
Is equal to the number of tooth tips of the gear 2 passing through the tip of the gear 2.

Thus, the AC voltage is taken out through the lead wire 6a and its frequency is measured to detect the rotation speed of the rotating shaft on which the gear 2 is mounted, thereby detecting engine speed, skid control, etc. for an automobile or the like. It will be used for various control operations.

[Problems to be solved by the invention]

However, the rotation sensor 1 having such a configuration requires a large number of components, and thus requires many and complicated assembling steps. Also, since the tip of the magnet 4 is fixed in the recess 3a of the pole body 3 by press-fitting or the like, dimensional accuracy between the magnet 4 and the recess 3a of the pole body 3 is required, and a technique for press-fitting is required. However, there is a problem in that defective products are likely to occur, manufacturing costs and assembly costs are increased, and miniaturization is difficult.

In view of the above, an object of the present invention is to provide a rotation sensor that has a simple structure and is easy to assemble, so that manufacturing costs and assembly costs can be reduced and the size can be reduced. I have.

[Means for solving the problem]

According to the present invention, the above object is to be arranged around a pole body whose tip is opposed to a rotating gear of a magnetic material mounted on a rotating shaft whose rotation speed is to be detected. A coil frame and a magnet portion to be provided at the rear end of the pole body are integrally formed by a plastic magnet, and a coil is wound around the coil frame portion, and the rotation sensor is configured by magnetizing the magnet portion. Achieved.

[Action]

According to this invention, since the coil frame portion and the magnet portion are formed integrally with the pole body by plastic molding, the magnet is extremely easily fixed to the pole body. At the same time, since the coil frame is also formed, the number of parts is reduced, so that the number of assembly steps is reduced and simplified, the manufacturing cost and the assembly cost are reduced, and the magnet is integrally assembled. It is made small.

Hereinafter, the present invention will be described in more detail with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of a rotation sensor according to the present invention. The rotation sensor 10 includes a magnetic rotating gear 11 mounted on a rotating shaft such as a wheel of an automobile to detect a rotating speed.
In contrast, a pole body 12 made of a magnetic material such as iron is provided close to the tip of the gear 11 so as to face the tooth tip. The pole body 12 is formed with a plastic molding portion 13 including a magnet portion 13a disposed in contact with the rear end face and a coil frame portion 13b located around the pole body 12. The bobbin and the flange of the coil frame 13b are preferably formed to be thin. Further, a coil 14 is wound around the coil frame portion 13b of the plastic molded portion 13.

The plastic molding section 13 is molded integrally with the pole body 12 by a plastic magnet,
Finally, the magnet portion 13a is magnetized so that the lines of magnetic force pass along the axial direction of the pole body 12 so that the left side has the N pole and the right side has the S pole or the opposite polarity as shown in the drawing. .

The rotation sensor 10 according to the present invention is configured as described above. Like the conventional rotation sensor 1, when the gear 11 is rotating, the coil wound around the coil frame 13b of the plastic molding 13 is formed. 14, AC voltage is generated,
By extracting this AC voltage via the lead wire 14a, the rotation speed of the rotation shaft to which the gear 11 is attached and the rotation speed of the wheels of the automobile connected to the rotation shaft are detected. .

In this way, various control operations such as engine control and skid control of an automobile or the like can be performed based on the detected rotation speed.

[Effect of the invention]

As described above, according to the present invention, a pole body whose tip is opposed to a rotating gear of a magnetic material mounted on a rotating shaft whose rotational speed is to be detected is disposed around the pole body. By integrally molding a coil section to be provided and a magnet section to be provided at the rear end of the pole body with a plastic magnet, winding a coil around the coil frame section, and magnetizing the magnet section, a rotation sensor is provided. Configured.

Therefore, since the coil frame portion and the magnet portion are integrally formed with the pole body by plastic molding, the magnet can be fixed to the pole body very easily. At the same time, since the coil frame portion is also formed, the number of components is reduced, so that the number of assembly steps is reduced and simplified, and the manufacturing cost and assembly cost can be reduced. Further, since the magnet portion is integrally assembled, the whole can be made compact.

Thus, according to the present invention, since the structure is simple and the assembling is easy, the manufacturing cost and the assembling cost can be reduced, and an extremely excellent rotation sensor which can be downsized can be provided. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the rotation sensor according to the present invention. FIG. 2 is a schematic sectional view showing an example of a conventional rotation sensor. 10 ... Rotation sensor; 11 ... Gear; 12 ... Pole body; 13
... plastic molded part; 13a ... magnet part; 13b ... coil frame part; 14 ... coil; 14a ... lead wire.

Claims (1)

(57) [Scope of request for utility model registration] 1. A coil frame to be disposed around a pole body whose tip is opposed to a rotating gear of a magnetic material mounted on a rotating shaft whose rotation speed is to be detected. The magnet part to be provided at the rear end of the pole body is integrally formed by a plastic magnet, and a coil is wound around the coil frame part, and the magnet part is magnetized to form a magnet. A rotation sensor.