JPH04134071U - magnetic sensor - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a magnetic sensor used for detecting the speed of a vehicle, etc., and particularly relates to a sealing structure for a resin case. [Structure] A case 1, a hole 2 provided in the case 1, a non-magnetic thin metal plate 8 that is insert molded into the case 1 in advance so as to cover the hole 2 integrally with the case 1,
A magnetic sensor is formed by the magnetoelectric transducer 3 provided facing the hole 2 and the sealant filled in the case 1, and the thin metal plate 8 prevents leakage of the sealant, and a separate This reduces the number of assembly steps by eliminating the number of steps required for sealing.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is equipped with a resin molded case used for vehicle speed detection etc. This relates to magnetic sensors.

0002

[Conventional technology]

In recent years, resin-molded cases are often used to make this type of sensor lighter and cheaper. I've become able to stay here.

0003 A conventional magnetic sensor will be explained below with reference to FIGS. 4 and 5. According to the same figure , 1 is a resin-molded case (hereinafter referred to as the case), and 2 is provided in case 1. The hole 3 faces the hole 2 and is attached to the magnetic field close to the surface of the case 1. A conversion element (hereinafter referred to as an element), 4 is a printed wiring board on which element 3 is mounted, 5 is a An electronic circuit section, 6 is a sealant filled in the case 1, and 7 is provided facing the element 3. It is a rotating disk (hereinafter referred to as a rotating disk) that is magnetized at regular intervals in the circumferential direction.

0004 The operation of the magnetic sensor configured as above is explained below. When the rotating disk 7 rotates, periodic changes in the magnetic field occur at a number of times proportional to the number of rotations. 3, and element 3 converts it into an electrical change. The electrical changes are reflected in the electronic circuit section. 5 processes and generates a digital signal a number of times proportional to the number of rotations. that signal The number of rotations of the rotating disk 7 is detected by measurement.

[0005]

[Problem that the idea aims to solve]

However, in the above conventional configuration, a gap occurs between the hole 2 and the element 3. Therefore, when filling the case 1 with the sealant 7 during assembly, cover the hole 2 with tape or the like. The product must be turned over to prevent leakage, and the quality is unstable due to this leakage prevention process. There was a problem.

[0006] This invention solves the above conventional problems and eliminates the leak-proofing process during assembly. The purpose is to provide a magnetic sensor with stable quality.

[0007]

[Means to solve the problem]

In order to solve the above problems, the magnetic sensor of the present invention is made of at least resin molded A case, a hole provided in this case, and an insert into the above case so as to cover this hole. The insert-molded thin metal plate, the element mounted facing the hole, and the case A sealing agent filled in the base and a constant circumferentially provided facing the magnetoelectric transducer. It consists of rotating disks magnetized at intervals.

[0008]

[Effect]

With the above configuration, the hole is inserted into the insert when filling the case with sealant during assembly. Because it is covered with a non-magnetic thin metal plate molded into a metal sheet, the leak-proofing process This is no longer necessary, and the quality can therefore be stabilized.

[0009]

【Example】

The magnetic sensor of the present invention will be described below with reference to an embodiment of FIGS. 1 to 3. Note that conventional Parts that are the same as the technology will be explained using the same numbers.

0010 According to the figure, 1 is a case, 2 is a hole provided in the case 1, and 8 covers the hole 2. 3 is a non-magnetic thin metal plate (hereinafter referred to as a thin metal plate) that is insert-molded into a moving shape. a magnetoelectric conversion element facing the hole 2 and mounted so as to be in contact with the non-magnetic thin metal plate 8; 4 is a printed wiring board to which a magnetoelectric conversion element is attached, 5 is an electronic circuit section, and 6 is a case 1. 7 is a sealant filled with a sealing agent filled with a sealing agent 7 arranged at regular intervals in the circumferential direction facing the magnetoelectric transducer. It is a rotating disk magnetized by .

[0011] Note that insert molding of the thin metal plate 8 into the case 1 is performed by bending it as shown in Figure 3. This prevents short shots from occurring at the part that supports the thin metal plate 8 during molding. The shape is designed to suppress the decrease in strength of this part.

0012 To explain the operation of the magnetic sensor configured as above, first, When the rotary disk 7 rotates, periodic changes in the magnetic field occur a number of times proportional to the number of rotations. This change in magnetic field is transmitted to the element 3 without being attenuated because the thin metal plate 8 is non-magnetic. So and is converted into an electrical change by the element 3. This electrical change occurs in the electronic circuit section 5. Therefore, it is processed and a digital signal is generated a number of times proportional to the number of rotations. this signal By measuring , the number of rotations of the rotating disk 7 is detected.

[0013] For example, the magnetic sensor described above uses a rotating disk as the main shaft of an automobile transmission. When linked together, it can be used as a vehicle speed sensor to detect vehicle speed. Ru.

[0014] Note that when a bent portion is provided at the end of the thin metal plate 8 as in the above embodiment, the It prevents short shots in this area during molding, suppresses the decrease in strength of this area, and seals. It is possible to prevent the thin metal plate from easily falling off when filling the adhesive 7.

[0015] In addition, a film with a thickness of 100 μm or less is applied to the insert part of the thin metal plate 8 in advance. It is also possible to use one coated with a resin film. In this case, insert can improve airtightness.

[0016] Furthermore, it is possible to use a thin metal plate 8 with a plurality of holes in the insert part. Therefore, since the thin metal plate is supported by the resin that passes through the hole, the insert part It is also possible to strengthen the strength of

[0017]

[Effect of the idea]

As described above, the magnetic sensor of the present invention has at least a case made of resin and a case made of resin. A hole provided in the case and an insert molded into the case to cover this hole. the thin metal plate, the element mounted facing the hole, and the case filled with It consists of a magnetized sealing agent and a magnetized rotating disk placed opposite the above element. This eliminates the need for a leak-proofing process when filling the case with sealant during assembly. This makes it possible to realize an excellent magnetic sensor with stable quality.

[Brief explanation of drawings]

[Fig. 1] An exploded perspective view of an embodiment of the magnetic sensor of the present invention.

[Figure 2] Ipsilateral sectional view

[Figure 3] Partially enlarged sectional view of the main parts of the case and the insert molded part of the non-magnetic thin metal plate

[Figure 4] Exploded perspective view of a conventional magnetic sensor

[Figure 5] Ipsilateral sectional view

[Explanation of symbols]

1 case 2 Hole 3 Magnetoelectric conversion element 5 Electronic circuit section 6 Sealant 7 Magnetized rotating disk 8 Non-magnetic thin metal plate

Claims (2)

[Scope of utility model registration request] 1. At least a resin-molded case, a hole provided in the case, and a non-magnetic thin metal plate insert-molded in the case to cover the hole.
A magnetoelectric transducer mounted facing the hole, an electronic circuit section, a sealant filled in the case, and a magnetized rotating disk provided facing the magnetoelectric transducer. Magnetic sensor configured. 2. The magnetic sensor according to claim 1, wherein the magnetoelectric conversion element is mounted so as to be in contact with a nonmagnetic thin metal plate.