JPH07325099A - Rotation speed detector - Google Patents

Abstract

PURPOSE:To provide the rotation speed detector which can prevent each terminal pin from being shortcircuited even if a housing becomes dented in the respective recessed sections of a bobbin. CONSTITUTION:Paired insulating spacers 1 are arranged in the respective recessed sections 18a and 18b of a bobbin 18, and each insulating spacer 1 is interposed between each small projection 20a and 20b of respective terminal pins 20 and a housing 13. Since these insulating spacers 1 are arranged in the respective recessed sections 18a and 18b of the bobbin 18, the respective sections 13b and 13c of the housing 13 are supported inwardly by these insulating spacers 1. This constitution thereby prevents these section 13b and 13c from becoming dented even if pressure is applied to the respective sections 13b and 13c of the housing 13 when molding resin 22 is molded with pressure. Even if they become dented, the housing 13 will never be brought in contact with the respective pins 20, shortcircuiting is thereby be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed detector for detecting the rotation speed of a wheel of an automobile or an output shaft of an engine.

[0002]

2. Description of the Related Art A rotational speed detector of this type is applied to, for example, an ABS (anti lock brake system) of an automobile,
Detects wheel rotation speed. In the case of application to this ABS, since the rotation speed detector is installed under severe conditions, the rotation speed detector is hermetically sealed to improve durability.

FIG. 7 illustrates a conventional rotation speed detector. In the figure, the magnetic rotor 11 is attached to the axle of an automobile and rotates together with the axle. The rotation speed detector 12 detects the rotation speed of the magnetic rotor 11.

In the rotational speed detector 12, a bracket 14 is brazed to the outer periphery of the housing 13, and the magnetic pole piece 15, the magnet 16, the yoke 17, the bobbin 18, and the coil 19 are integrated in the housing 13. The cable 21 is connected to each terminal pin 20 of the bobbin 18 and the housing 1
The opening 13 a of No. 3 is sealed with the mold resin 22.

The magnetic rotor 11 has a large number of irregularities such as gear teeth. Therefore, when the magnetic rotor 11 rotates, the magnetic flux passing through the magnetic pole piece 15 changes, and the current of the coil 19 changes. The output of the coil 19 is taken out through the cable 21 and the rotation speed is detected based on the output of the coil 19.

By the way, two recesses 18a and 18b are formed on the outer circumference of the bobbin 18.
Small protrusions 20a, 20b of each terminal pin 20 on 8a, 18b
Is located. These small protrusions 20a and 20b are projected outward as shown by the dotted line. The wire rods of the coil 19 are bent and connected to the small protrusions 20a and 20b protruding outward, and the small protrusions 20a and 20b are bent and retracted.
To store.

[0007]

However, since the molding resin 22 is pressure-molded at the time of sealing with the molding resin 22, pressure is also applied to the housing 13 and the respective portions 13b, 13 of the housing 13 are compressed.
c has been recessed in the recesses 18a and 18b of the bobbin 18. In this case, each part 13b, 13c of the housing 13
May contact the small protrusions 20a and 20b of each terminal pin 20, which causes a short circuit failure of each terminal pin 20.

The occurrence rate of such a short circuit defect becomes high when the wall of the housing 13 is made thin in order to reduce the weight of the rotation speed detector. Therefore, if the wall of the housing 13 is made thick and the strength of the housing 13 is increased, the occurrence rate of the short circuit defect can be suppressed, but the weight reduction and the cost reduction of the rotation speed detector are hindered.

Therefore, an object of the present invention is to provide a rotation speed detector which does not cause a short circuit failure of each terminal pin even when the housing is recessed in each recess of the bobbin.

[0010]

In order to solve the above problems, the present invention detects a rotation of a magnetic rotor by inserting a coil, a bobbin around which the coil is wound, and a bobbin inserted in the center of the bobbin. At least a magnetic pole piece, a housing for accommodating the bobbin, and a sealing synthetic resin for sealing the opening of the housing are provided, and a recess is formed on the outer periphery of the bobbin, and a terminal pin of the bobbin is provided in the recess. In the rotation speed detector in which the coil wire is pulled in and connected to the terminal pin in the recess, an insulator is interposed between the terminal pin drawn in the recess of the bobbin and the housing.

For example, the insulator is synthetic resin rubber,
The portion of the terminal pin pulled into the recess of the bobbin is covered.

Further, for example, the insulator is an adhesive tape having an insulating property and covers the concave portion of the bobbin.

[0013]

According to the above invention, since the insulator is interposed between the terminal pin portion drawn into the recess of the bobbin and the housing, the molding pressure is applied to the housing during molding of the sealing synthetic resin. Therefore, even if the housing is dented at the concave portion of the bobbin, the housing does not come into direct contact with the terminal pin.

The insulator may be synthetic resin rubber or an insulating adhesive tape.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a longitudinal section of an embodiment of the rotation speed detector of the present invention. In addition, FIG. 2 shows A- of FIG.
A cross section taken along A'is shown. Note that FIG.
In FIG. 2 and FIGS. 2A and 2B, parts that perform the same functions as those of the conventional rotation speed detector shown in FIG.

In the rotational speed detector of this embodiment, a pair of insulating spacers 1 are arranged in the recesses 18a and 18b of the bobbin 18, and these insulating spacers 1 are attached to the small protrusions 20a and 20b of each terminal pin 20 and the housing 13. Intervenes in between.

These insulating spacers 1 are molded of synthetic resin having an insulating property and have a shape as shown in FIG.

Since these insulating spacers 1 are arranged in the respective recesses 18a, 18b of the bobbin 18, the respective portions 13b, 13c of the housing 13 are supported from inside by these insulating spacers 1. Therefore, the mold resin 22
At the time of pressure molding of each part 13b of the housing 13,
Even if pressure is applied to 13c, these parts 13b, 13
c is not dented. Further, even if it is recessed, the housing 13 does not come into contact with the small protrusions 20a and 20b, and a short circuit defect does not occur.

FIG. 4 shows another embodiment of the rotation speed detector of the present invention. Further, FIG. 5 shows a cross section taken along the line BB ′ of FIG.

In this rotation speed detector, the respective synthetic resin rubbers 2 are filled in the respective concave portions 18a and 18b of the bobbin 18, and the small protrusions 20a and 20b of the respective terminal pins 20 are covered with these synthetic resin rubbers 2. ing.

Of course, these synthetic resin rubbers 2 have an insulating property. Also, these synthetic resin rubbers 2 are
Each of the recesses 18 of the bobbin 18 is to be filled.
Regardless of the shape of a and 18b, they will fit in these recesses 18a and 18b.

Since these synthetic resin rubbers 2 are soft, they are deformed by external pressure. Therefore, these synthetic resin rubbers 2 are attached to the respective portions 13b, 13 of the housing 13.
Although the depression of c cannot be prevented, the contact between the housing 13 and each of the small protrusions 20a and 20b can be prevented.

FIG. 6 shows another embodiment of the rotation speed detector of the present invention in cross section.

Here, the insulating adhesive tape 3 is wound around the bobbin 18. The insulating adhesive tape 3 covers the recesses 18a and 18b of the bobbin 18 to cover the terminal pins 2
It is interposed between 0 and the housing 13 to insulate them.

[0026]

As described above, in the rotation speed detector of the present invention, since the insulator is interposed between the housing of the terminal pin drawn into the recess of the bobbin and the housing, the housing is located at the recess of the bobbin. Even if it is dented, this housing does not directly contact the terminal pins, and short-circuit failure does not occur. Therefore, it is possible to reduce the weight and cost of the rotation speed detector by thinning the wall of the housing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a rotation speed detector of the present invention.

FIG. 2 is a transverse cross-sectional view taken along the line AA ′ in FIG.

FIG. 3 is a perspective view showing an insulating spacer in the rotation speed detector of FIG.

FIG. 4 is a vertical sectional view showing another embodiment of the rotation speed detector of the present invention.

5 is a transverse cross-sectional view taken along the line BB ′ of FIG.

FIG. 6 is a transverse sectional view showing another embodiment of the rotation speed detector of the present invention.

FIG. 7 is a vertical cross-sectional view illustrating a conventional rotation speed detector.

[Explanation of symbols]

 1 Insulating Spacer 2 Synthetic Resin Rubber 3 Insulating Adhesive Tape 11 Magnetic Rotor 12 Rotational Speed Detector 13 Housing 15 Magnetic Pole 16 Magnet 18 Bobbin 19 Coil 20 Terminal Pin 22 Mold Resin

Claims (3)

[Claims] 1. A coil, a bobbin around which the coil is wound, a magnetic pole element inserted in the center of the bobbin for sensing rotation of a magnetic rotor, a housing for accommodating the bobbin, and an opening of the housing. At least a sealing synthetic resin for sealing the portion is formed, a recess is formed on the outer periphery of the bobbin, the terminal pin of the bobbin is drawn into the recess, and the wire of the coil is entangled and connected to the terminal pin in the recess. In the rotation speed detector, a rotation speed detector in which an insulator is interposed between the housing and the portion of the terminal pin drawn into the recess of the bobbin. 2. The rotation speed detector according to claim 1, wherein the insulator is a synthetic resin rubber and covers a portion of the terminal pin drawn into the recess of the bobbin. 3. The rotation speed detector according to claim 1, wherein the insulator is an adhesive tape having an insulating property, and covers the concave portion of the bobbin.