JPH0736059U - Wheel speed sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a wheel speed sensor which is easy to manufacture and has sufficient strength to ensure internal watertightness and which is highly sensitive, by molding functional parts by resin molding. [Configuration] Magnet 2, iron core 3, bobbin 4, winding coil 5,
Functional parts such as the yoke 6 and the pole piece 7 are integrated with the terminal 8 by the resin 9, which is housed in the resin housing 1 and the upper part is fixed by the second resin molded body 11. The projection of the pole piece 7 is covered with a non-magnetic metal cap 13,
A hermetic seal 14 is provided inside the projecting opening.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotation sensor for detecting the rotation speed and rotation speed of a rotating body such as an automobile wheel.

[0002]

[Prior art]

 Various types of rotation detection methods, such as an electromagnetic power generation method and a method using a magnetoresistive element or a Hall element, are known as rotation detection methods adopted in a rotation sensor for detecting the rotation speed of a rotating body. Such a rotation sensor is generally mounted at an appropriate position such as a wheel support portion, and is wound on a magnet, an iron core, a pole piece provided in a cylindrical housing made of a non-magnetic material, and a bobbin fitted around the outer periphery of the iron core. Fig. 3 shows three typical examples consisting of wound winding coils.

(A) is a pole piece protruding type, (b) and (c) are built-in types, 1 is housing, 2 is magnet, 3 is iron core, 4 is bobbin, 5 is winding coil, 6 is Yoke 7 is a pole piece, and X is a sensor rotor. The sensor rotor X is composed of a gear-shaped disc having ridges and valleys alternately formed on the outer edge as shown in the drawing.

With respect to the rotation sensor arranged as described above, when the sensor rotor is rotated by the rotation of the rotating body, the magnitude of magnetism penetrating the iron core is changed by the rotation, and an AC voltage is generated across the winding coil. To do. This AC voltage is output from the output line, detected as a pulse signal by a binarization circuit in a detection circuit (not shown), and the rotational speed is obtained by counting this pulse signal.

[0005]

[Problems to be solved by the device]

 However, in the conventional wheel speed sensor having the above-mentioned configuration, the functional components are housed in the housing, which is formed by deep drawing a non-magnetic material (stainless steel) and is housed in the housing. Since functional parts need to be fixed with resin or the like, there is a problem that the manufacturing cost increases and the processing cost increases.

In consideration of the above-mentioned problems of the conventional wheel speed sensor, the present invention makes it easy to manufacture and to prevent malfunction by integrating the functional parts including terminals by resin molding and storing them in a resin housing. An object of the present invention is to provide an economical and reliable wheel speed sensor which has a small number of detection sensitivity and a high detection sensitivity.

[0007]

[Means for Solving the Problems]

 As a means for solving the above problems, the present invention forms a functional component including an output terminal by resin molding and integrally fixes it, and a cap made of non-magnetic metal is attached to a magnetic pole of an iron core protruding below the resin molded body. Cover it, insert it into a resin housing, provide a sealant inside the opening where the cap projects from the bottom of the housing, connect the output wire to the terminal, and integrate the outer periphery with a second resin molded body. It is a wheel speed sensor that is made up of.

[0008]

[Action]

 Since the wheel speed sensor configured as described above is integrally formed with the terminals according to the rotation of the sensor rotor, failure is unlikely to occur even when vibration of the vehicle is applied, and reliability is secured. Since the magnetic poles are protected by a thin stainless steel cap, wheel speed signals can be detected with high sensitivity. A sufficient watertightness is ensured because the protruding part is provided with a hermetic seal.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a main sectional view of a wheel speed sensor of the embodiment. The wheel speed sensor shown in the figure is of a built-in pole piece type, and has functional parts such as a magnet 2, an iron core 3, a bobbin 4, a winding coil 5, a yoke 6 and a pole piece 7 as in the conventional example. The above-mentioned components including 8 are integrally molded with resin 9, and are housed in the housing 1 and the outer periphery is fixed with the second resin molded body 11 with the output line 10 connected to the terminal 8. . Reference numeral 12 is a mounting bracket integrally provided on the resin molded body 11.

With the functional parts housed in the housing 1, the pole piece 7 projects from an opening provided in the lower bottom of the housing 1. At this projecting portion, a cap made of non-magnetic metal, for example, stainless steel is used. 13 is covered, and a hermetic seal 14 using a rubber O-ring is provided inside the opening. X is a sensor rotor.

The resin-made housing 1 is made of, for example, a resin in which nylon 66 is filled with glass fiber (filling rate 30%). A resin having a thickness of about 1 to 2 mm and sufficient strength can be obtained by injection molding. Can be produced at low cost.

The wheel speed sensor of the embodiment configured as described above outputs a wheel speed signal from the output line when the sensor rotor X rotates. Such a wheel speed sensor is manufactured as follows. First, the housing 1 is made of resin and the cap 13 is inserted into the hole used at the end, and at this time, the O-ring hermetic seal 14 is inserted between the cap 13 and the housing 1. A functional component integrally formed with the winding coil 5, the pole piece 7, the magnet 2 and the like is inserted, and the upper portion is molded with nylon resin and sealed.

The detection portion of the end of the pole piece 7 enhances the detection sensitivity, and therefore it is preferable that the cover of that portion is thin, but if the pole piece rusts, the detection sensitivity decreases, and therefore it cannot be exposed. If the cover is made of resin, the strength will be weak (because it is attached to the wheel part of an automobile, so it will be hit by small stones), so it is necessary to use a cap 13 made of stainless steel. Can be secured.

If a sealing seal 14 made of a rubber O-ring is inserted between the stainless cap 13 and the resin housing 1, the O-ring is pressed when the upper nylon molded body is molded. Ensure airtightness inside the housing.

[0015]

[Effects] As described in detail above, the wheel speed sensor of the present invention integrates functional parts into a resin molded body and stores this in a resin housing, and the magnetic pole protruding downward is a non-magnetic metal cap. As a result, a sealing material is provided on the part where the cap protrudes from the housing to ensure the sealing performance. Therefore, it is easy to manufacture, the processing cost and material cost are low, and the wheel speed is highly reliable with no malfunctions. The advantage is that a sensor is obtained.

[Brief description of drawings]

FIG. 1 is a main sectional view of a wheel speed sensor according to an embodiment.

FIG. 2 is a main sectional view of a wheel speed sensor of another example.

FIG. 3 is a main sectional view of a conventional wheel speed sensor.

[Explanation of symbols]

 1 Housing 2 Magnet 3 Iron Core 4 Bobbin 5 Winding Coil 6 Yoke 7 Pole Piece 8 Terminal 9 Resin 10 Output Line 11 Second Resin Molded Body 12 Mounting Bracket 13 Cap 14 Seal Seal

Claims (1)

[Scope of utility model registration request] 1. A functional component including an output terminal is resin-molded and integrally fixed, and a magnetic pole of an iron core projecting to the lower portion of the resin-molded body is covered with a non-magnetic metal cap, which is made of a resin. A wheel speed sensor which is inserted into the inside of the housing, a sealing material is provided inside the opening where the cap protrudes from the lower bottom of the housing, the output wire is connected to the terminal, and the outer circumference of the output speed is integrated with a second resin molded body.