JPH0645202Y2 - Sensitivity adjustment device for position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a sensitivity adjusting device of a position detecting device for detecting a stroke position of a piston in a fluid pressure cylinder.

[Conventional technology]

Conventionally, a fluid pressure cylinder such as a hydraulic cylinder or a pneumatic cylinder is equipped with a position detection device for detecting the stroke position of the piston.

A conventional position detecting device is configured by arranging a printed board on which a magnetic sensor such as a magnetoresistive element or a hall element is attached in a housing made of synthetic resin or the like.

Such a position detecting device is attached to, for example, an outer peripheral surface of a cylinder tube, and detects a magnetic field of a permanent magnet attached to a piston sliding in the cylinder tube.

That is, the magnetic flux density passing through the magnetic sensor changes according to the position of the piston in the stroke direction (axial direction), and the magnitude of the detection signal output by the magnetic sensor changes accordingly. When the detection signal becomes larger than a preset threshold value, the detection signal which is a signal indicating that the piston has approached the position detection device is output.

However, in the fluid pressure cylinder, the wall thickness of the cylinder tube varies depending on the material of the cylinder tube and the pressure of the fluid used. For example, stainless steel has a smaller wall thickness than an aluminum alloy, and hydraulics have a larger wall thickness than pneumatics.

When the wall thickness of the cylinder tube changes in this way, the distance between the position detecting device and the permanent magnet, that is, the distance between the magnetic sensor and the permanent magnet changes, so that the strength of the magnetic field applied to the magnetic sensor changes.

Therefore, if the sensitivity of the position detection device is constant and constant, the detection operation width of the position detection device (width of the detection signal output from the position detection device in the stroke direction of the piston when used in a fluid pressure resin binder of different thickness ) Has changed, and there is a problem that stable detection operation cannot be performed.

For example, if the wall thickness of the cylinder tube is thin, the detection operation width becomes large, which decreases the detection accuracy, and if the wall thickness is too thin, multi-point operation (detection operation occurs multiple times depending on the stroke direction position). May occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a sensitivity adjusting device capable of easily adjusting the sensitivity of a position detecting device.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, a sensitivity adjusting device according to the present invention includes an adjusting plate made of a soft magnetic material for reducing the strength of a magnetic field applied to the magnetic sensor, and an adjusting plate between the adjusting plate and the magnetic sensor. A spacer made of a non-magnetic material, the adjusting plate and the spacer are integrated by adhering their surfaces to each other, and the spacer is provided on the surface opposite to the adjusting plate. Is provided with an adhesive layer for adhering to the surface of the magnetic sensor.

[Action]

The sensitivity adjusting device is attached to the surface of the magnetic sensor using the adhesive layer.

The adjusting plate reduces the magnetic flux passing through the magnetic sensor, and reduces the sensitivity of the position detecting device.

The sensitivity of the position detection device is adjusted according to the thickness of the spacer.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front view of a sensitivity adjusting device 10 according to the present invention, and FIG. 2 is a position detecting device 2 having the sensitivity adjusting device 10 according to the present invention.
3 is a plan view of the sensitivity adjusting device 10. FIG.

In FIG. 2, the position detecting device 2 includes a fluid pressure cylinder 3
Is attached to the outer peripheral surface of the cylinder tube 4 of
It operates by the magnetic field of the permanent magnet 6 mounted on the piston 5 sliding on the inner peripheral surface of the cylinder tube 4. The permanent magnet 6 has an N pole or an S pole along the stroke direction of the fluid pressure cylinder 3 (direction of arrow M1 in FIG. 1).

The position detecting device 2 includes a housing 11, a printed board 12, a light emitting diode 13, a magnetic sensor 14, a sensitivity adjusting device 10, a lead wire 17, and the like.

The housing 11 is made of a non-magnetic material such as synthetic resin,
It is formed in a casing or a container.

The printed circuit board 12 has a light emitting diode 13 and a magnetic sensor.
14, a comparator (not shown), and other circuit components are mounted to form a detection circuit for detecting the stroke position of the piston 5. The printed circuit board 12 is arranged inside the housing 11 and fixed by being filled with a synthetic resin or the like.

The light emitting diode 13 lights up according to the detection state based on the detection signal of the magnetic sensor 14.

The magnetic sensor 14 detects the magnetic field of the permanent magnet 6 and outputs a detection signal according to the strength of the magnetic field. For example, a magnetic resistance element or a Hall element is used.

The magnetic sensor 14 is arranged so that its sensitivity to the magnetic field in the stroke direction of the fluid pressure cylinder 3 (direction of arrow M1) is maximized.

The lead wire 17 is for outputting a detection signal from the above-mentioned detection circuit and for supplying power to the detection circuit.

The sensitivity adjusting device 10 is attached to the upper surface (the surface opposite to the permanent magnet 6) of the magnetic sensor 14.

In FIG. 1, the sensitivity adjusting device 10 includes an adjusting plate 16, a spacer 15, and double-sided tapes 21 and 22.

The adjusting plate 16 is for reducing the strength of the magnetic field applied to the magnetic sensor 11, is made of a soft magnetic material such as an amorphous alloy, and has a plate shape slightly larger than the area of the magnetic sensor 14.

The spacer 15 is arranged between the adjusting plate 16 and the magnetic sensor 14, and is a plate-like member made of a non-magnetic material such as synthetic resin. The sensitivity of the position detecting device 2 is adjusted by setting the thickness of the spacer 15 to an appropriate value.

The spacer 15 and the adjusting plate 16 are bonded and integrated by a double-sided tape 22 interposed therebetween, and the spacer 15
A double-sided tape 21 for adhering to the magnetic sensor 14 is attached to the other surface of the.

The sensitivity adjusting device 10 is arranged and attached such that the longitudinal direction of the adjusting plate 16 is parallel to the direction of the magnetic field (direction of arrow M1) that the magnetic sensor 14 senses.

Next, a method of manufacturing the sensitivity adjusting device 10 will be described.

4 to 6 are views showing the manufacturing process of the sensitivity adjusting device 10.

As shown in FIG. 4, first, for example, a rectangle made of an amorphous alloy having a thickness of about several tens of microns (for example, a trade name “Magnesir” manufactured by Tajima Steel Co., Ltd.) and each side having a length of about several centimeters. Sheet-like body 16B, sheet-like body 1
Double-sided tape 22B of the same size as 6B, spacer plate 15B made of a synthetic resin plate such as polycarbonate, mount 21b on one side
The double-sided tape 21B to which is adhered is adhered in this order to produce a laminated body 10B as shown in FIG.

Next, as shown in FIG. 6, the laminated body 10B is placed on a suitable stand with the side of the mount 21b facing down, and is cut into the outer shape of the sensitivity adjusting device 10 with a single-tooth cutter.

In cutting the laminated body 10B, it is cut along the vertical cutting line M2 in the vertical direction at a predetermined pitch, and then along the horizontal cutting line M3 in the horizontal direction at a predetermined pitch. Also, mount 21b
Make a half cut so as not to cut.

As a result, a large number of sensitivity adjusting devices 10 are aligned and adhered on the mount 21b.

When attaching the sensitivity adjusting device 10 to the magnetic sensor 14,
By peeling off the sensitivity adjusting device 10 from the mount 21b, one sensitivity adjusting device 10 is separated from the laminated body 10B, and the adhesive surface is exposed by this, so that the adhesive surface is used to stick to the surface of the magnetic sensor 14. wear.

FIG. 7 is a diagram showing the state of the magnetic field generated by the permanent magnet 6.

In FIG. 7, the curve Ha indicated by the solid line is the sensitivity adjusting device 10
7 shows the strength of the magnetic field due to the effective component (the component in the direction of arrow M1) of the magnetic flux passing through the magnetic sensor 14 in the absence of the magnetic field.

A curved line Hb indicated by a broken line shows the strength of the magnetic field due to the effective component of the magnetic flux passing through the magnetic sensor 14 when the sensitivity adjusting device 10 is provided.

According to these curves Ha and Hb, the largest peak just above the permanent magnet 6 and the two smaller peaks appear on both sides thereof, respectively.
The case with 10 is smaller than that without.

This is because a part of the magnetic flux that has passed through the magnetic sensor 14 passes through the adjusting plate 16 so that the magnetic flux that passes through the magnetic sensor 14 decreases.

The line Ls in FIG. 7 shows the threshold value for the position detecting device 2 to output a detection signal.

As a result, the position detecting device 2 when the sensitivity adjusting device 10 is provided
The operating width Eb of is smaller than the operating width Ea when the sensitivity adjusting device 10 is not provided.

That is, by providing the adjusting plate 16, the operation width of the position detecting device 2 is reduced. Adjustment plate 16 and magnetic sensor
As the distance from 14 decreases, that is, the spacer
As the plate thickness of 15 decreases, the magnetic flux passing through the magnetic sensor 14 decreases and the operation width decreases. Therefore, the sensitivity of the position detecting device 2 can be adjusted by setting the plate thickness of the spacer 15 appropriately.

The strength of the magnetic field applied to the magnetic sensor 14 differs depending on the wall thickness of the cylinder tube 4 and the strength of the permanent magnet 6. Therefore, according to the specifications of the fluid pressure cylinder 3, the spacer 15 (spacer plate 15B It is sufficient to adjust the sensitivity of the position detection device 2 by setting the plate thickness in ().

According to the above-described embodiment, the sensitivity adjusting device 10 has a magnetic sensor.
Since the sensitivity of the position detection device 2 can be adjusted by sticking it on the surface of 14, the sensitivity adjustment is extremely easy.

Sensitivity adjustment device 10 using various spacers 15 with different plate thickness
Are prepared in advance, and they may be selected according to the sensitivity specification of the position detection device 2.

Further, since the laminated body 10B is formed by bonding the double-sided tapes 21 and 22, the laminated body 10B can be easily manufactured.

Moreover, since the sensitivity adjusting device 10 may be peeled off from the mount 21b of the laminated body 10B and attached to the magnetic sensor 14, the assembly work of the position detecting device 2 is extremely easy, and the manufacturing cost of the position detecting device 2 is reduced. be able to.

According to the above-described embodiment, the adjusting plate 16 is attached to the outer surface side of the magnetic sensor 14, so that the adjusting plate 16 acts to magnetically shield the magnetic sensor 14 against a magnetic field coming from the outside. The sensitivity to the external magnetic field is reduced, and the malfunction due to it is less likely to occur.

In the above embodiment, the magnetic sensor 14, the spacer 15,
The size, shape, and quantity of the adjusting plate 16, the number of the light emitting diodes 13, the color, the lighting state, the configuration of the detection circuit, the structure and the shape of the position detection device 2, and the like can be variously changed other than those described above.

The position detecting device 2 described above can be used for detecting various moving objects other than the piston 5 of the fluid pressure cylinder 3.

[Effect of device]

According to the present invention, the sensitivity of the position detecting device can be easily adjusted, and the manufacturing cost of the position detecting device can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of a sensitivity adjusting device according to the present invention, FIG. 2 is a sectional front view of a position detecting device having the sensitivity adjusting device according to the present invention, and FIG. 3 is a plan view of the sensitivity adjusting device. FIG. 6 to FIG. 6 are views showing the manufacturing process of the sensitivity adjusting device, and FIG. 7 is a view showing the state of the magnetic field by the permanent magnet. 2 ... Position detection device, 5 ... Piston (moving object), 6
...... Permanent magnet, 10 …… Sensitivity adjustment device, 14 …… Magnetic sensor, 15 …… Spacer, 16 …… Adjustment plate, 21 …… Double-sided tape (adhesive layer).

Claims (1)

[Scope of utility model registration request] 1. A position detection device for detecting the position of a moving object, comprising a magnetic sensor for detecting a magnetic field of a permanent magnet provided on the moving object and outputting a detection signal according to the strength of the magnetic field. A sensitivity adjusting device comprising a soft magnetic material adjusting plate for reducing the strength of a magnetic field applied to the magnetic sensor, and a non-magnetic material arranged between the adjusting plate and the magnetic sensor. A spacer, and the adjusting plate and the spacer are integrated by adhering their surfaces to each other, and the surface of the spacer opposite to the adjusting plate is attached to the surface of the magnetic sensor. A sensitivity adjusting device for a position detecting device, which is provided with an adhesive layer for