JP2564919B2 - Non-contact displacement detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-contact type displacement detector, which uses a magnetoelectric conversion element, and is compact and suitable for mounting on a vehicle in a bad environment. It relates to an inexpensive displacement detector.

[Prior Art] Conventionally, a contact type displacement detector using a sliding resistor has been widely used for detecting the amount of displacement of an operating device or a driving device of each part of a vehicle, but with the recent progress of car electronics. Under such circumstances, a non-contact type displacement detector using a magnetoelectric conversion element such as a Hall element or a magnetoresistive element is small and easy to manufacture. It is attracting attention because of its high sensitivity and good output stability.

[Problems to be Solved by the Invention] By the way, when a displacement detector using the magnetoelectric conversion element is used in a vehicle, it may be compact, resistant to electromagnetic noise, and water-releasing. Although required, a displacement detector satisfying such a request has not been proposed yet.

An object of the present invention is to provide a non-contact type displacement detector which satisfies the above-mentioned requirements and can be suitably used for mounting on a vehicle.

[Means for Solving the Problems] A non-contact type displacement detector of the present invention is a rotary shaft that is connected to an object to be measured and that rotates according to the displacement, and one end of this rotary shaft is liquid-tightly pressed. A housing having a first opening and a second opening closed by a shielding container covered with a non-magnetic conductive material, and disposed on an end surface of one end of the rotating shaft, and integrated with the rotating shaft. A permanent magnet rotating in the direction of, and while continuously changing the output signal according to the change of the magnetic field of the permanent magnet, the magnetoelectric conversion element arranged facing the permanent magnet, and the output signal from the magnetoelectric conversion element, A signal line extending from the magnetoelectric conversion element to the outside of the housing in a liquid-tight manner is provided, and the magnetoelectric conversion element is arranged in the shielding container.

[Operation] According to the above configuration, since the magnetoelectric conversion element is housed in the shielding container having the conductive material as the container wall, the output of the magnetoelectric conversion element is not disturbed by electromagnetic noise.

In addition, the rotary shaft and the signal line are
Since it is arranged in a liquid-tight manner, water or the like does not enter from the outside of the housing.

Further, since the permanent magnet is provided on the end surface of the rotary shaft inserted in the housing and the magnetoelectric conversion element is opposed to the permanent magnet, the entire detector becomes compact.

[First Embodiment] In FIGS. 1 and 2, a detector housing 1 is shown.
Is a resin cylindrical body with a diameter gradually decreasing from the upper end to the lower end, and the inner peripheral wall near the lower end is a partition wall that divides the inside of the cylinder into upper and lower parts, and the shaft support opening 13 is formed in the center thereof. It is provided. Further, one side wall of the housing 1 is formed as a signal line connecting portion 14 by protruding in a cylindrical shape.

The rotary shaft 2 is pushed from below through the shaft support opening 13, and the tip end 21 of the rotary shaft 2 reaches a substantially central position in the housing 1. A resin magnet holder 31 having a U-shaped or U-shaped cross section is arranged at this central position, and the permanent magnets 3A are made to face each other with a gap therebetween by heat staking or bonding. An iron piece 32 is fixedly supported in contact with 3B and its back. An insert fitting embedded in the bottom wall of the magnet holder 31 is caulked and fixed to the tip end surface of the rotating shaft. Also,
An oil seal 71 is provided on the outer periphery of the rotary shaft 2 in the lower end opening 11 of the housing 1 to maintain liquid tightness.

The iron piece 32 is intended to increase the magnetic field strength to improve the sensitivity, and from the same viewpoint, the permanent magnets 3A and 3B are Sm.
It is desirable to use a rare earth magnet such as a Co type magnet.

The upper end opening 12 of the housing 1 has a small diameter at the inner circumference so as to project into a step, and the outer peripheral edge is adhered and fixed to this stepped portion to hold the substrate holder.
41 is provided, and the substrate holder 41 and the housing 1 form a storage chamber 100. The substrate holder 41 is a substantially circular plate body having a standing wall on the peripheral edge, and is made of a non-magnetic conductive material such as Al or Cu. The central portion thereof projects downward in a cylindrical shape to become an element holding portion 411, and this holding portion 411 is the permanent magnet 3 described above.
It is located between A and 3B.

A SIP type Hall element 5 is provided in the element holding portion 411, and a lead extending upward from this is the substrate holder.
It is connected to a printed circuit board 8 which is adhesively fixed on 41. The printed circuit board 8 is formed with an amplifier circuit section for amplifying the output of several hundred mV of the Hall element 5 to about 0 to 5 V. The position of the board 8 is convex at three positions on the outer periphery of the board holder 41. Positioning is performed by the stopper portion 412 formed on the. The printed circuit board 8 and the amplifier circuit section form a signal processing means for processing the output signal from the Hall element 5.

The opening 12 is a cover body made of a non-magnetic conductive material such as Al.
The cover body 42 and the substrate holder 41 are covered with 42 to form a shielding container 4 for preventing the intrusion of electromagnetic waves. The cover body 42 is caulked liquid-tightly on the outer periphery of the opening 12 through an O-ring 72 provided on the end face of the opening 12.

An H (Hybrid) IC terminal 81 extends from the printed circuit board 8 and is connected to one end of a housing terminal 82 embedded in the side wall of the housing 1 by soldering or the like. The other end of the housing terminal 82 projects into the signal line connection portion 14 of the housing 1.

A waterproof grommet 73 is fitted in the opening of the connecting portion 14, the signal wire 6 of the signal cable C is introduced into the connecting portion 14 through the grommet 73, and the wire terminal 83 at the tip of the signal wire 6 is the housing. It is connected to the terminal 82 by the push nut method.

In the detector having the above structure, the base end of the rotary shaft 2 is connected to the object to be measured by an appropriate means and rotates according to the displacement thereof. Along with this rotation, the pair of permanent magnets 3A and 3B rotate around the Hall element 5, the magnetic field direction changes, and the Hall element output changes. This is shown in Fig. 3, and while the rotating shaft 2 rotates from -90 degrees to +91 degrees, the element power voltage is-
It continuously changes on the sine wave from VA to + VA.

Then, the element output is amplified by the amplifier circuit on the printed circuit board 8, passes through the terminals 81, 82 and 83, and then the signal line 6
Taken out by.

In this case, since the Hall element 5 and the printed circuit board 8 are housed in the shielding container 4, they are not affected by electromagnetic noise, and the oil seal 71, the O-ring 72, and the grommet 73 open the housing 1. Since it is liquid-tightly closed, water and the like will not enter the housing.

In order to further enhance the effect against the influence of electromagnetic noise, as shown in FIGS. 12 and 13, a feedthrough capacitor 84 is provided between the HIC terminal 81 and the housing terminal 82.
You should put.

[Second Embodiment] As shown in FIG. 4, the magnet holder 31 is formed by bending a plate material of a soft magnetic material such as SPCC, and cutting and raising a part of the standing wall to form a supporting portion 311. If the permanent magnets 3A and 3B are adhered and fixed on this, the cost can be further reduced.

[Third Embodiment] In order to further ensure the positioning of the above-mentioned SPI type Hall element, the holding portion 411 of the substrate holder 41 is arranged along the flat outer shape of the Hall element 5 as shown in FIG. It is better to draw with a step.

Fourth Embodiment Further, for the same purpose, a part of the outer shape of the Hall element 5 is
As shown in FIG. 6, a columnar protrusion 51 that can be fitted into the holding portion 411 without any gap may be formed.

[Fifth Embodiment] In FIG. 7, the magnet holder 22 is formed integrally by cutting the tip of the rotary shaft 2 to reduce the cost.
In this case, the clip 23 is used to position the rotary shaft 2 in the axial direction.

In this embodiment, a chip type is used as the Hall element 5,
It is fixed by reflow soldering or the like to the lead printed circuit board 52 fitted in the holding portion 411 of the circuit board holder 41.

Further, in order to more easily fix the substrate holder 41 and the printed circuit board 8, a projection 15 is provided on the stepped surface of the inner circumference of the housing 1, and after the projection 15 is inserted into the mounting hole of the board holder 41 or the like, heat is applied. It is fixed by caulking. According to this, as compared with the bonding of the first embodiment, the number of mounting steps is reduced,
Further, the Hall element 5 is not applied with excessive heat.

The housing 1 has a connection port 16 on one side wall facing downward.
The signal line 6 having the waterproof plug 75 attached thereto is pushed into the connection port 16 and the wire terminal 83 is directly connected to the HIC terminal 81 by ultrasonic welding or the like. With such a structure, water intrusion from the connecting portion can be prevented, and the lateral projection amount of the housing 1 can be reduced as compared with the first embodiment using the grommet.

Furthermore, the seal of the cover body 42 is replaced with the slice packing 74 instead of the O-ring of the first embodiment to reduce the cost.

This embodiment also has the same effect as that of the first embodiment.

[Sixth Embodiment] FIGS. 8 and 9 show a magnetoresistive element using a magnetoresistive element 9. Such magnetoresistive element 9
Since it can be manufactured by a flip chip, it can be directly fixed on the printed circuit board 8 by reflow soldering or the like as shown in the drawing, and the permanent magnet 3 is made of a resin-made thick disk provided at the tip of the rotary shaft. One magnet holder 33 is provided in an eccentric state.

As the rotating shaft 2 rotates, the relative position of the eccentric permanent magnet 3 changes with respect to the magnetoresistive element 9, whereby the magnetoresistive element 9 emits an output according to the rotation angle of the rotating shaft 2. .

 The other structure is the same as that of the first embodiment.

This embodiment has the same effect as that of the first embodiment, and can further simplify the structure.

In addition, since a ferrite magnet or the like can be used as the permanent magnet, it is inexpensive.

[Seventh Embodiment] As shown in FIG. 10, a waterproof connector 61 is provided at the connection terminal of the signal line 6, and the connector pin 62 connected to the signal line 6 is detachably connected to the housing terminal 82. good.

[Embodiment 8] The substrate holder 41 may be integrally formed of a conductive and non-magnetic molding material other than a metal material, and after molding with a resin material or the like, its inner peripheral wall 41a (Fig. 11) or outer circumference. The wall 41b can also be formed by applying a conductive paint.

[Ninth Embodiment] As shown in FIG. 14, the substrate holder 41 is not provided with the element holding portion, and the inner wall 1a of the housing 1 is coated with a conductive paint or plated to resist electromagnetic noise. It is also possible to have.

EFFECTS OF THE INVENTION As described above, in the non-contact displacement detector of the present invention, the rotary shaft is liquid-tightly inserted through the first opening of the housing, and the permanent magnet is disposed on the end face thereof. By closing the second opening of the above with a shielding container and arranging the magnetoelectric conversion element in this shielding container, the element output is not disturbed by electromagnetic noise, water does not enter, and The entire detector can be made compact.

Therefore, it can be suitably used for applications mounted on vehicles that are harsh in the environment.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show a first embodiment of the present invention.
The figure is an overall vertical sectional view of the detector, which is a sectional view taken along line I-I of FIG. 2, and FIG. 2 is a horizontal sectional view thereof, II-II of FIG.
FIG. 3 is a sectional view taken along the line, FIG. 3 is an output characteristic diagram of a Hall element, and FIG. 4 is a perspective view of a magnet holder showing a second embodiment of the present invention.
5 and 6 show the third and fourth aspects of the present invention, respectively.
FIG. 7 is a sectional view of an essential part of a substrate holder showing an embodiment, FIG. 7 is an overall vertical sectional view of a detector showing a fifth embodiment of the present invention, and FIGS. 8 and 9 show a sixth embodiment of the present invention. 8 is an overall vertical sectional view of the detector, which is a sectional view taken along line VIII-VIII in FIG. 9, and FIG. 9 is an overall horizontal sectional view of the detector, which is IX- in FIG.
A sectional view taken along line IX, FIG. 10 is a sectional view of a signal line connecting portion showing a seventh embodiment of the present invention, FIG. 11 is a perspective view of a substrate holder showing an eighth embodiment of the present invention, and FIG. And FIG. 13 shows a modification of the first embodiment of the present invention, FIG. 12 is an overall vertical sectional view of the detector, a sectional view taken along the line XII-XII in FIG. 13, and FIG. 12 is a sectional view taken along line XIII-XIII in FIG. 12, and FIG. 14 is an overall vertical sectional view of a detector showing a ninth embodiment of the present invention. 1 …… Housing 11 …… First opening, 12 …… Second opening 2 …… Rotating shaft 21 …… Tip (one end) 22 …… Magnet holder 3, 3A, 3B …… Permanent magnet 31 …… Magnet holder 4 ... Shielding container 41 ... Substrate holder 42 ... Cover body 5 ... Hall element (magnetoelectric conversion element) 6 ... Signal line 8 ... Printed circuit board (signal processing means) 9 ... Magnetoresistive element (magnetoelectric element) Transducer) 100 …… Storing room

Claims (3)

(57) [Claims] 1. A rotary shaft which is connected to an object to be measured and rotates according to its displacement, and one end of the rotary shaft is covered with a first opening for liquid-tightly pressing and a magnetically conductive material. A housing having a second opening closed with a shielding container, a permanent magnet disposed on an end surface of the one end of the rotating shaft and rotating integrally with the rotating shaft, and a permanent magnet corresponding to a change in the magnetic field of the permanent magnet. While continuously changing the output signal, the magnetoelectric conversion element disposed so as to face the permanent magnet and the output signal from the magnetoelectric conversion element are liquid-tightly extended from the magnetoelectric conversion element to the outside of the housing. A non-contact type displacement detector, comprising: a signal line that is exposed, wherein the magnetoelectric conversion element is arranged in the shielding container. 2. The non-contact type displacement detector according to claim 1, wherein the shielding container is provided with a signal processing means for processing an output signal of the magnetoelectric conversion. 3. The non-contact displacement detector according to claim 1, wherein the magnetoelectric conversion element and the signal processing means are directly attached to the inner surface of the shielding container.