JPH07329744A - Rotary sensor - Google Patents

Abstract

PURPOSE:To provide a highly reliable rotary sensor which can prevent housing deformation and can prevent a housing from contacting terminal binding pieces when a sensor head having a knuckle bush is formed. CONSTITUTION:A bobbin 3 is housed in a housing 1, and the terminal portion of a coil 2 retained by the bobbin 3 is connected to the binding pieces 6a of terminals 6 fitted to the bobbin 3, and the binding pieces 6a are bent at a recessed portion 7 provided at the bobbin 3. A knuckle bush to be inserted into the hole 9a of a bracket 9 is integrally formed at a synthetic resin sensor head 8 to seal opening of the housing 1. By providing at the knuckle bush cutout portions 11 facing the recessed portion 7 of the bobbin 3, the deformation of the housing 1 toward the recessed portion 7 at the time of sensor head 8 formation, is prevented, and contact between the housing 1 and the binding pieces 6a is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor for detecting the rotation speed of a rotating body such as a wheel.

[0002]

2. Description of the Related Art A gear rotor is mounted on a wheel of an automobile, a rotation sensor is provided so as to face the gear rotor, and an alternating induction current is generated in a coil of the rotation sensor due to a change in magnetic flux density due to the rotation of the gear rotor. , It has been conventionally performed to detect the rotational speed of the wheel from the induced current.

The rotation sensor shown in FIG. 4 is conventionally known. In this rotation sensor, a bobbin 3 holding a coil 2 is housed inside a housing 1, and a magnet 5 is in contact with a rear end surface of a core 4 inserted in the center of the bobbin 3.

The wire 2 pulled out from the coil 2
The terminal portion of a is a binding piece 6 of the terminal 6 attached to the bobbin 3.
The entanglement piece 6a is bent toward the recess 7 formed on the outer periphery of the bobbin 3 so that the entanglement piece 6a may hit the opening of the housing 1 when the bobbin 3 is stored in the housing 1. To prevent.

Further, a sensor head 8 made of synthetic resin is molded in the opening of the housing 1 to seal the opening of the housing 1, and a knuckle bush 10 for inserting a hole 9a of a bracket 9 into the lower portion of the sensor head 8. Are integrally molded to fix the bracket 9.

[0006]

By the way, in the above rotation sensor, the knuckle bush 10 includes the housing 1.
Since it covers the entire outer periphery of the intermediate portion, the position facing the recess 7 of the bobbin 3 of the housing 1 is deformed inward by the molding pressure during injection molding of the sensor head 8 having the knuckle bush 10. There was a risk of contacting the entanglement piece 6a of 6 and causing insulation failure.

An object of the present invention is to provide a rotation sensor capable of preventing the housing from coming into contact with the binding piece of the terminal at the time of injection molding of a sensor head having a knuckle bush.

[0008]

In order to solve the above problems, according to the present invention, a bobbin for supporting a coil is housed in a housing, and a magnet is attached to a rear end surface of a core inserted through the center of the bobbin. The terminal supported by the bobbin is provided with a binding piece that is bent into a recess formed on the outer circumference of the bobbin after the wire end portion drawn from the coil is bound, and seals the opening of the housing. A rotation sensor in which a sensor head made of synthetic resin is integrally provided with a knuckle bush inserted into a hole of a sensor mounting bracket, and a configuration in which a cutout portion is provided at a position facing the recess of the knuckle bush is adopted. There is.

[0009]

As described above, when the knuckle bush is provided with the cutout portion, the molding pressure does not act on the position of the knuckle bush facing the recess of the bobbin during injection molding of the sensor head, and the housing is It is possible to prevent deformation toward the recess, and it is possible to reliably hold the housing and the binding member in a non-contact state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

The same parts as those of the conventional example shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, the sensor head 8 made of synthetic resin for sealing the opening of the housing 1 has a knuckle bush 10 in the lower portion, and the knuckle bush 10 is inserted into a hole 9a of the bracket 9 and the knuckle bush 10 is inserted into the bracket 9. It extends downward.

A plurality of cutouts 11 are formed at the lower end of the knuckle bush 10, and each cutout 11 faces a recess 7 provided in the bobbin 3.

When the notch 11 is formed in the knuckle bush 10 as described above, during injection molding of the sensor head 8,
It is possible to prevent the housing 1 from being deformed toward the recess 7 because the molding pressure does not act on the position facing the recess 7 of the housing 1.

Therefore, it is possible to reliably secure a certain gap formed between the housing 1 and the entanglement piece 6a at the initial stage of housing the bobbin, and to prevent insulation failure.

In the case of the embodiment, the notch 11 is formed at the lower end of the knuckle bush 10, but a hole may be formed instead of the notch 11.

[0017]

As described above, in the rotation sensor according to the present invention, the knuckle bush integrally formed with the sensor head has the notch facing the recess of the bobbin. Can be prevented from being deformed inward and coming into contact with the binding piece of the terminal, and the reliability of the rotation sensor can be improved.

Further, since the contact between the housing and the entanglement piece can be prevented in a state where the knuckle bush is secured to a predetermined length, the function of the knuckle bush is not impaired and the cutout portion is formed. As a result, the amount of resin is reduced, and the weight of the rotation sensor can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a rotation sensor according to the present invention.

[Fig. 2] Bottom view of the above

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view showing a conventional rotation sensor.

[Explanation of symbols]

 1 Housing 2 Coil 2a Wire 3 Bobbin 4 Core 5 Magnet 6 Terminal 6a Entangling Piece 7 Recess 8 Sensor Head 9 Bracket 9a Hole 10 Knuckle Bush 11 Notch

Claims (1)

[Claims] 1. A bobbin for supporting a coil is housed in a housing, a magnet is brought into contact with a rear end surface of a core inserted through the center of the bobbin, and a terminal supported by the bobbin is pulled out from the coil. A knuckle inserted through the hole of the sensor mounting bracket in a sensor head made of synthetic resin, which is provided with a foldable piece that is bent in a recess formed on the outer periphery of the bobbin after entwining the wire end portion and seals the opening of the housing. A rotation sensor in which a bush is integrally provided, wherein a notch is provided at a position facing the recess of the knuckle bush.