JP3315443B2 - Vehicle wheel speed sensor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention simplifies the assembling process by providing a step on a holder for mounting a circuit board on which a sensor element is mounted and supporting a case fitted with the holder on the step. The present invention relates to a sensor device that has improved resistance to moisture and mechanical strength.

[0002]

2. Description of the Related Art As a sensor device in which a sensor element is fixed in a case by a mold member, there is a rotation sensor shown in FIG. This sensor is provided so as to face a sensor rotor 3 mounted on a tire rim of an automobile, and has a case 1 in which a magnetoelectric conversion element 2 such as a magnetoresistive element or a Hall element is built.

Conventionally, in such a rotation sensor, as shown in FIG. 1, a hollow case 1 having a mounting flange at one end thereof is used to improve airtightness and improve moisture resistance and mechanical strength. After a magneto-resistive element 2 ′ in which the magneto-electric conversion element 2 and the terminal 4 are fixed with a thermosetting resin is arranged, a magnet 5 is joined to the magneto-resistive element 2 ′, and a circuit board 6 is mounted thereon. Along with the circuit components 7 mounted on the circuit board 6 and the connection cable 8 for extracting sensor output, etc., the thermosetting resin injected from the opening of the case 1 is pressurized for a certain time to cure the resin. Then, the molding is performed so as to be integrated with the case 1, thereby fixing and holding the magnetoelectric conversion element 2 in the case 1.

[0004] However, in the above-described device, the molding process must be performed twice in order to fix the magnetoelectric conversion element 2 and the other circuit components 7 to the case 1. The work of injecting and hardening becomes complicated and complicated, and it takes a long time to assemble, so that there is a problem in mass productivity.

Further, at this time, there is a problem that unnecessary stress due to high temperature and high pressure accompanying the molding process is applied to the sensor element 2 to deteriorate the characteristics.

Further, there is a difference in the coefficient of thermal expansion between the case 1 integrally molded and the thermosetting resin filled in the case 1. Therefore, the temperature cycle applied during use causes the case 1 to repeat. There is also a problem that cracks and the like occur between the resin 1 and the filling resin, airtightness is reduced, and the device is easily affected by moisture.

As one solution to these problems, for example, a hollow case and a holder to be fitted into the case are formed in a mold in advance, and a sensor element, a circuit component and the like are attached to the formed holder. By inserting into the hollow case and sealing the opening of the hollow case by molding using a nylon material, the molding process was omitted, mass productivity was improved, and the holder and the case with the sensor element were provided. By doing so, it is conceivable to prevent a decrease in airtightness caused by a difference in the coefficient of thermal expansion between the two.

[0008]

However, in the case of sealing by the above-described nylon molding, when the nylon member at the time of molding is welded to the peripheral edge of the case and the sealing is performed, the holder in the case is also pressurized. Not only damages the sensor element directly attached to the holder, but also causes the holder to move due to the applied pressure and collide with the inner wall of the case, deteriorating the characteristics of the element provided at the tip of the holder, It can be destroyed. For this reason,
There is a problem that the above-described assembly for improving mass productivity and airtightness cannot be performed by using the case and the holder.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a sensor element from being damaged by a pressurizing force at the time of sealing a peripheral edge and to assemble a sensor device using the case and the holder. is there.

[0010]

In order to solve the above-mentioned problems, according to the present invention, a circuit board on which a rotation sensor element is mounted is attached to a front end face, and a step having a diameter larger than the front end face is formed at a rear end. A holder consisting of a base formed around
The circuit board and the one end of the front end surface is connected, a connecting lead which is taken from the rear end side of the holder and the other end through the holder, a stepped portion abutting to an opening end portion to be sealed of the holder a, a case for accommodating and fitting the holder from the front end side, is formed toward the open end of the case, the case opening suffered base rear portion including the joint portion of the stepped portion and the case of the holder Thus, a configuration consisting of an end portion and a sealing member fixed to the step portion of the holder was adopted.

At this time, the contact between the step portion of the holder and the end portion of the case opening causes the circuit board disposed on the front end surface of the base of the holder and the inner wall of the front end of the case covering the base. A gap may be formed between them.

Further, fitting portions may be provided on the base side portion and the case side portion of the holder.

[0013]

In the sensor device configured as described above, the circuit board is placed on the front end surface of the base, connected to the connection leads, and then the holder is inserted into the case, and both are sealed with a sealing member. Assembled by.

At this time, the holder fitted into the case stops the advancement of the holder into the case when the step of the holder comes into contact with the case opening end. Further, when sealing is performed by the sealing member, the pressing force applied at that time is stopped by the holder opening end by being supported by the case opening end, and in any case, The sensor element and the circuit board on which the sensor element is mounted are prevented from colliding with the case and being damaged. At this time, the inside of the case is sealed and the inside and outside of the case are separated by contacting the step portion of the holder with the case opening end, so that the pressing force is not directly applied to the inside of the case.

On the other hand, the connection between the circuit board in the case sealed in this way and the external circuit is made via connection leads and connection cables which are connected to the terminals of the circuit board and which are sealed by penetrating the base. Done by

Further, since the case and the holder to be sealed in this manner are not integrally formed, even if a difference in thermal shrinkage occurs between both due to, for example, a temperature cycle, the difference in shrinkage does not affect each other. No air-tightness, no cracks, etc., and excellent moisture resistance.

As described above, the sensor device assembled without performing the resin injection does not require the injection and hardening work accompanying the resin injection, so that the process time can be reduced.

Further, in the case where a gap is formed between the circuit board disposed on the base end surface and the inner wall of the case end covering the base end portion, the circuit board and the case are separated by the gap. That is, even if the case is distorted or bent due to, for example, a pressure applied during sealing or a stress applied during use, the distortion or bending is prevented from being directly applied to the sensor element of the circuit board, and the sensor Element breakage and deterioration of characteristics can be prevented.

Further, in the case where a fitting portion which fits into the base side and the case side is provided, the positioning in the axial direction when the holder is inserted into the case can be performed, and the direction of the sensor element can be specified. Therefore, the sensing area can be kept unchanged for each sensor to be assembled.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. The sensor device of the present embodiment shown in FIG. 1 is a magnetic rotation sensor using a Hall IC 19 as a magnetic sensor as a sensor element, and includes a holder 10, a circuit board 6 ′ mounted on the holder 10, a case 11, , Its case 11
And a sealing member 12 for sealing the holder 10.

The holder 10 comprises a cylindrical base 13 which is formed of the peripheral to the support wall 14 of the front end surface 14 ', large-diameter stepped from the front end surface 14 around the rear end 16 of the base 13 The portion 17 is formed, and the connection lead 15 is
I have.

The base 13 is formed of a resin. At this time, the connection leads 15 connected to the connection cable 8 are integrally formed to be buried in the base 13, and one of the connection lead ends 15 '. Is projected from the front end face 14 of the base 13, and the other connection lead end 15 ″ connected to the connection cable 8 is projected from the rear end face 16.

On the side of the base 13, there is formed a fitting groove 18 extending from the tip to the step as shown in FIG.

The circuit board 6 ′ mounts the Hall IC 19 and circuit components, is connected to the Hall IC 19, and is connected to one connection lead end 15 ′ protruding from the front end face 14 of the base 13. It has a terminal 21 in which a hole is formed. The circuit board 6 'on which the Hall IC 19 is mounted is placed on a support wall 14' at the tip of the base 13, protrudes from the base end face 14, and the terminal 2
1 is connected by soldering to the one connection lead end 15 ′ penetrating through the hole 1 , so that the installation position of the Hall IC 19 is determined and at the same time, it is electrically connected.

On the other hand, an insertion hole 20 is formed in the base end surface 14 facing the Hall IC 19 of the circuit board 6 'fixed by the connection lead 15 as described above, and the insertion hole 20 is provided with the magnet 5'. Are press-fitted (inserted). At this time, the tip of the magnet 5 'is connected to the circuit board 6'
And the distance between the magnet 5 ' and the Hall IC 19 does not change for each sensor to be assembled and is always constant, thereby reducing the variation in the intensity of the bias magnetic field applied to the Hall IC 19, thereby improving the characteristics. I am trying to be stable.

At this time, a magnetic material such as an iron plate is disposed between the tip of the magnet 5 'and the circuit board 6' to prevent magnetic flux, so that the magnetic flux is efficiently applied to the Hall IC 19. Thereby, the sensitivity may be increased.

The case 11 is a hollow cylindrical container having a mounting flange 23 on one side. The case 11 is fitted to the base 13 and is fitted from the tip thereof.
It comes into contact with the step 17 of the holder 10 and covers the base 13. At this time, a gap d is formed between the circuit board 6 'and the inner wall 11' at the end of the case 11.

A groove 18 'is formed on the side of the case 11 to be fitted with the fitting groove 18 of the base 13, so that the direction in which the base 13 is fitted into the case 11 is regulated. The orientation of the holder 10 when it is inserted into the case 11 is always set to the same direction, and the Hall IC 1 of the holder 10 is
9 are made constant.

The sealing member 12 is a cap that covers the rear end face 16 of the holder 10, and its peripheral edge is fixed to the opening end 22 of the case 11 that contacts the step 17 of the holder 10 , so that the case 11 and its The holder 10 inserted into the case 11 is sealed. This cap is formed of a thermoplastic resin, and in this case, the connection cable 8 connected to an external circuit connected to the other connection lead end 15 ″ protruding from the rear end face 16 of the holder 10 and the other connection lead end 15 ″. Are integrally formed.

This embodiment is configured as described above. For example, in this sensor device, the case 11 and the holder 10 are individually formed by a mold or injection molding.
At this time, the connection lead 15 connected to the connection cable 8 connected to the external circuit is embedded and penetrated into the holder 10 by being integrally formed.

The base 1 of the holder 10 thus formed
At the same time as inserting the magnet 5 ′ into the insertion hole 20 of the distal end surface 14 of the base 3, the circuit board 6 ′ on which the Hall IC 19 separately assembled is mounted on the support wall at the distal end of the base 13. The terminal 21 is attached to the terminal 21 by soldering through one lead end 15 'of the connection lead 15 protruding from the tip end surface 14, and is simultaneously fixed and electrically connected. As described above, the holder 10 on which the circuit board 6 ′ has been attached is fitted into the case 11 from the tip of the base 13. At this time, the fitting groove 18 of the base 13 and the groove 18 ′ of the case 11 By fitting and fitting
The orientation of the Hall IC 19 of the inserted circuit board 6 'is not changed for each sensor to be assembled, so that the direction of the magneto-sensitive region in which a magnetic field is effectively applied to the Hall element in use is not changed.

The holder 10 thus fitted into the case 11 has the step 17 abutting against the open end 21 of the case 11, the holder 10 is supported by the open end 21, and the circuit board 6 ′ and the inner wall at the tip of the case 11. A gap d is formed between the gap d.

On the other hand, a cap-shaped sealing member 12 made of a thermoplastic resin is formed on the rear end face 16 of the holder 10 fitted in the case 11 by resin molding, for example, injection molding. although sealed step 17 Togafu end 2 2 and the holder 10, the cable 8 at this time, which is at the same time, connected to the connection leads 15 and connection leads 15
Are also integrally formed.

At this time, the holder 10 is pressed into the case 11 by the pressing force at the time of resin molding, and the pressing force is supported by the case opening end 22 which contacts the step 17 of the holder 10. By doing so, the holder 10
Of the circuit board 6 ′ on the distal end surface 14 of the base 13 is prevented from colliding with the inner wall 11 ′ at the distal end of the case 11. Further, since the holder 10 through which the connection lead 15 has penetrated separates the inside of the case 11 from the outside of the case 11, the holder 10 does not transmit the pressing force into the case 11.

The sensor device assembled in this manner is assembled by fitting the holder 10 into the case 11 and is not integrally formed because molding by resin injection is not performed. Even if a heat shrinkage difference occurs, the shrinkage difference does not interact with each other, and the holder 10 and the case 11 do not crack. Further, the case 11 and the holder 10 are sealed by resin molding, so that the case 11 and the holder 10 are highly airtight and resistant to humidity. Further, fixing and arrangement of the Hall IC 19, the magnet 5 ', the circuit board 6' and the like can be performed without injecting resin, so that mass productivity is good.

This sensor device is mounted on a tire rim of an automobile which is opposed to the sensor rotor 3 which rotates together with the wheels, for example, by a mounting flange. The IC 19 is used as a vehicle speed sensor that detects the signal by the IC 19 and outputs the detection signal to an external circuit via the connection lead 15 and the cable 8. At this time, for example, foreign matter is caught between the sensor rotor 3 and the case 11, Even if excessive stress is applied to the
Since the stress due to the deformation is not directly applied to the Hall IC 19 on the circuit board due to the gap d formed between the inner wall 11 'at the tip of the case 11 and the circuit board 6' , it does not affect the detection signal. , Strong against external impact.

In this embodiment, fitting grooves 18 and 18 'are provided in the holder 10 and the case 11 as fitting portions. However, the grooves 18 and 18' are not limited to those described above. The deformed grooves 18, 18 'shown in FIG.
And the fitting portion is provided with a groove 1
8 and 18 ', as shown in FIG.
1 and one side of the base 13 may be formed in a planar shape,
A projection may be provided as shown in FIG.

In this embodiment, the case 11 and the sealing member 12 are made of resin. However, the case 11 and the sealing member 12 may be made of, for example, a metal case and a metal cap. Both may be sealed with a hermetic seal.

Further, in this embodiment, the rotation sensor having the magneto-electric conversion element mounted on the sensor element has been described. However, the sensor device of the present invention is not limited to this. It is also suitable for use in a temperature sensor using a temperature conversion element, a radiation detection device using a radiation converter, and the like.

[0040]

According to the present invention, the case and the holder fitted into the case are sealed by a step formed on the holder so that the opening end of the case supports the pressing force at the time of sealing. Since it is possible to prevent the sensor element from being damaged by the pressing force at the time of sealing, assembly using a case and a holder excellent in mass productivity and airtightness can be performed.

Therefore, unlike the conventional sealing, it is not necessary to inject the resin into the case to seal the sensor element, so that the sensor element is not damaged and the yield during assembly is improved. Also, it exhibits excellent airtightness against temperature cycles. Further, since it is suitable for assembly using resin molding, mass productivity is also good.

In particular, when a gap is formed between the circuit board of the holder and the inner wall at the tip of the case, the holder is resistant to external stress and can be used in a severe environment.

Further, in the case where the holder and the case are provided with a fitting portion, the direction of the sensor element when the holder is fitted into the case can be determined in one direction, so that the sensing direction of the sensor device during mass production is kept constant. Can be kept.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is a cross-sectional view of FIG.

FIGS. 3 (a), (b) and (c) are action diagrams of another embodiment.

FIG. 4 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

6 'Circuit board 8 Connection cable 10 Holder 11 Case 11' Inner wall of case tip 12 Sealing member 13 Base 14 Base end face 15 Connection lead 15 'One lead end of connection lead 15' The other lead of connection lead End 17 Step of holder 18, 18 'Fitting groove 19 Hall IC 21 Terminal d Gap

Continuing from the front page (72) Inventor Hidetoshi Saito 1-1-1, Kunyokita, Itami City Inside Itami Works, Sumitomo Electric Industries, Ltd. (72) Inventor Masahiro Kume 1-1-1, Kunyokita, Itami City Sumitomo Electric Industrial Co., Ltd. (56) References JP-A-5-273321 (JP, A) JP-A-60-91209 (JP, A) JP-A-63-231212 (JP, A) Jpn. , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01R 1/04 G01P 3/44-3/495

Claims (3)

(57) [Claims] 1. A holder comprising a base 13 having a circuit board 6 'on which a rotation sensor element 19 is mounted, mounted on a front end face, and a step 17 having a diameter larger than the front end face formed around a rear end. 10, a connection lead 15 having one end connected to the circuit board 6 ′ on the front end surface, the other end penetrating the holder 10 and being taken out from the rear end side of the holder 10, and abutting against the step 17 of the holder 10. has an open end 22 which is sealed Te, a case 11 for housing by fitting the holder 10 from its distal end side, is formed toward the open end 22 of the case 11, front
A case opening end 22 and a holder cover the rear end of the base 13 including the joint between the step 17 of the holder 10 and the case 11.
And a sealing member 12 fixed to the step portion 17 of the vehicle wheel speed sensor device 10. 2. The base 13 of the holder 10 is contacted by the step 17 of the holder 10 and the case opening end 22.
The vehicle wheel speed according to claim 1, wherein a gap (d) is formed between a circuit board (6 ') disposed on the front end surface and an inner wall (11') of the front end of the case (11) covering the base (13). Sensor device. 3. The base 13 has a columnar shape.
A hollow cylindrical container having a mounting flange 23 serving as the open end 22 of the case 11 on one side, to said <br/> base 13 side and the case 11 side, and each other fit each other 3. The vehicle wheel speed sensor device according to claim 1, further comprising a fitting portion for positioning the base and the case .