JPH10221191A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make material intensive and reduce its cost, by coating at least one of a case and a component with necessary material by thermal spraying. SOLUTION: The whole external surface of a resin case 4 of a pressure sensor is coated with ceramic material by a thermal spraying equipment 23. Thereby fire resistance can be ensured without using an expensive metal case, and the coping with complicated configuration is easily enabled as compared with a metal case. The thermal spray material is not restricted to ceramic, and metal material may be used. Alloy may be also used as metal material. Cases composed of the same resin material can be applied to a sensor for which fire resistance is required and also to a sensor for which fire resistance is not required, so that the material can be made intensive. Corrosion resistance can be improved by spraying ceramic or the like on the case of a limit switch. The case of a vibration sensor or other sensor device or the internal components may be coated with necessary material by thermal spraying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of sensor devices such as limit switches and pressure sensors, and more particularly to a sensor device coated with required materials such as various metals, alloys, and ceramics by a thermal spraying technique.

[0002]

2. Description of the Related Art In this type of sensor device, it is necessary to select a material corresponding to a desired property as a constituent material. For example, if a product is required to have fire resistance, heat resistance, and dielectric properties, It was necessary to use metal instead of resin.

[0003] However, since a material corresponding to various properties required as described above must be selected, even if the switch or the sensor has the same internal structure, the case may be different depending on the application. It is not possible to consolidate the materials, and depending on the application, it is not possible to use a resin material, which makes it difficult to process a complicated shape with a high cost. There is a drawback that you have to choose.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a sensor device capable of consolidating materials and reducing costs. .

[0005]

In order to achieve the above-mentioned object, the present invention is configured as follows.

That is, the present invention according to claim 1 is a sensor device having a case in which parts are housed therein, wherein at least one of the case and the parts is coated with a required material by thermal spraying. It is.

According to a second aspect of the present invention, in the first aspect, a metal material or a ceramic material is coated by thermal spraying on an outer surface of the case made of a resin material as the required material. is there.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a capacitance type sensor device for detecting a pressure based on a capacitance between opposed electrodes housed in a case. The electrode is formed by coating a member made of a resin material with a conductive material as the required material by thermal spraying.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the plate-shaped member has a spacer portion formed integrally with the resin material at a peripheral portion thereof.

According to a fifth aspect of the present invention, there is provided a differential transformer type sensor device for detecting a pressure based on an output of a differential transformer according to the first or second aspect of the present invention, wherein the sensor device slides on an inner surface of a spool. The sliding body is made of a resin material, and the sliding body has a sliding portion that slides on the inner surface of the spool and a separated portion that is separated from the inner surface of the spool, and the separated portion is made of a magnetic material as the required material. The core is coated by thermal spraying.

According to the first aspect of the present invention, at least one of the case and the component is coated with a required material by thermal spraying. By spraying required materials such as alloys, ceramics, etc., various properties such as heat resistance, wear resistance, corrosion resistance, conductivity, dielectric properties, heat insulation properties, etc. can be improved depending on the application.

In addition, since it is possible to respond by selecting the material to be sprayed, instead of changing the base material according to the application,
It is possible to consolidate the base material constituting the case or the component.

According to the second aspect of the present invention, since the outer surface of the case made of a resin material is coated with a metal material or a ceramic material by thermal spraying, fire resistance is secured in an inexpensive resin case. You can do it.

According to the third aspect of the present invention, in a capacitance type pressure sensor device, an electrode can be formed by spraying a conductive material on a resin member, and the sprayed area is changed by masking to thereby form an electrode area. Therefore, the capacitance can be changed.

According to the fourth aspect of the present invention, the plate-like member has a spacer portion formed integrally with the resin material at a peripheral portion thereof, so that compared to a case where electrodes and spacers are separately provided. , The assembly man-hour can be reduced.

According to a fifth aspect of the present invention, in the pressure sensor device of the differential transformer type, the sliding body that slides on the inner surface of the spool is made of a resin material, and a magnetic material is sprayed on a separated portion of the sliding body. Since the core is formed as a core, the core can be constituted by one component of an inexpensive resin material.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing an appearance of an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, and FIG. 3 is a sensor unit of FIG. FIG. 3 is an exploded perspective view of FIG.

In this embodiment, a description will be given by applying the present invention to a capacitance type pressure sensor for detecting the pressure of a fluid such as a gas.

The pressure sensor 1 is configured by housing various components such as electrodes in a synthetic resin case 4 comprising a cover 2 and a base 3. LCP), polyphenylene sulfide (PPS), ABS, synthetic resin such as polybutylene terephthalate (PBT).

The pressure sensor 1 is basically a capacitance type sensor having a pressure receiving unit 5, a differential type sensor unit 6, and a signal processing unit 7, as shown in FIG. is there.

The pressure receiving unit 5 includes the above-described base 3 having the pressure introduction port 8 into which a pressure fluid such as gas is introduced, an O-ring 9 provided at an outer peripheral position on a bottom portion of the base 3, and
The diaphragm 10 includes a diaphragm 10 that is displaced in accordance with the pressure of a fluid, and a diaphragm retainer 11 that presses and fixes a peripheral portion of the diaphragm 10. The pressure receiving side of the diaphragm 10 communicates with the pressure inlet 8. I have.

The sensor unit 6 has an electrode holder 12 and an electrode holder 13, between which a movable electrode 15 having a plunger 14 mounted at the center as shown in an exploded perspective view of FIG. And first and second fixed electrodes 16 and 17 each having a configuration described below and opposed to both surfaces of the movable electrode 15, and first and second fixed electrodes 16 and 17 respectively opposed to the first and second fixed electrodes 16 and 17. Shield electrodes 18, 19
And a spring member 20 for pressing them into the electrode holder 12. Electrode holder 1
2, the second shield electrode 19, the first and second fixed electrodes 1
Holes 12a, 19a, 16a, and 1 are provided at the centers of the holes 6 and 17 so that the plunger 14 of the movable electrode 15 can be inserted and displaced.
7a are formed, and each of the electrodes 15-1
Terminal portions 15b to 19b are respectively formed on the peripheral edge portion 9.

The signal processing unit 7 has a printed wiring board 21 disposed between the electrode holder 13 and the cover 2, and connects a lead wire 22 connected to the printed wiring board 21 and led out of the case 4. An oscillation circuit (not shown) that oscillates at an oscillation frequency according to the capacitance between the movable electrode 15 and the first and second fixed electrodes 16 and 17 is provided on the printed wiring board 21. And a pulse output circuit (not shown) for outputting a pulse signal according to the difference between the oscillation frequencies.

In the pressure sensor 1 having the above configuration, the diaphragm 10 is displaced in accordance with the pressure of the fluid from the pressure inlet 8 of the base 3, and the diaphragm 10 displaces the movable electrode 15 via the plunger 14. As a result, the capacitance between the movable electrode 15 and the first and second fixed electrodes 16 and 17 changes, thereby outputting a number of pulse signals proportional to the pressure to be detected.

In the pressure sensor 1 of this embodiment, the fire resistance is ensured without using a metal case, and even if a fire occurs, for example, the case melts and flammable gas leaks. In order to prevent the pressure sensor 1 from coming out, the outer surface of the resin case 4 of the pressure sensor 1 is sprayed with a ceramic material by a thermal spraying device 23 and coated on the entire outer surface of the case 4 as shown in FIG. ing.

As the thermal spraying method, various thermal spraying methods such as gas thermal spraying and electric thermal spraying can be adopted. In this embodiment, a ceramic powder is sprayed by plasma spraying in the atmosphere, and a plasma spraying gun as a spraying device 23 is used. Pressure sensor 1
The outer surface of the case 4 and the lead wire 22 drawn out of the case 4 are coated. The thermal spray material is not limited to ceramic, but may be a metal material, and an alloy may be used as the metal material. Further, the thermal spraying on the case 4 may be performed in a state where the pressure sensor 1 is assembled,
It may be performed in the case 4 alone.

As described above, since the outer surface of the resin case 4 is coated with ceramic, fire resistance can be ensured without using a costly metal case, and further, compared with a metal case. A complicated shape can be easily handled.

Further, since the pressure sensor for any of the applications requiring fire resistance and the application not requiring fire resistance can use the case made of the same resin material, it is possible to consolidate the materials.

Further, in this embodiment, the first and second fixed electrodes 16 and 17 of the sensor unit 6 are configured as follows.

That is, in this embodiment, the first and second fixed electrodes 16 and 17 shown in FIGS. 2 and 3 are not made of metal as in the conventional case but made of a resin plate. Then, a conductive material such as aluminum is coated by spraying a conductive material such as aluminum on the side of the plate material facing the movable electrode 15 and a lead-out portion on the peripheral edge thereof as shown by oblique lines, and the electrode portions 16c, 17c and the terminal portion 16b are coated. , 17b
Further, as shown in FIG. 5 which is an enlarged view of section A in FIG.
Spacers 16d and 17d forming a gap with the movable electrode 15 and a gap with the shield electrodes 18 and 19 are integrally formed of the same resin material.

Conventionally, the gap between the fixed electrode and the movable electrode and the gap between the fixed electrode and the shield electrode have been formed by individual spacers made of an insulating film. By integrally molding with the fixed electrodes 16 and 17 as described above, the number of parts and the number of assembling steps can be reduced, and the cost can be reduced.

As shown in FIG. 6, by changing the masking at the time of spraying the conductive material, the area of the electrode portions 16c and 17c of the fixed electrodes 16 and 17 and therefore the capacitance can be changed. That is, there is no need to change the component dimensions according to the magnitude of the capacitance. FIG.
Here, only the second fixed electrode 17 is representatively shown.

In this embodiment, the outer surface of the resin case 4 is coated with ceramic or the like by thermal spraying to secure fire resistance. However, as another embodiment of the present invention, the inner surface of the case 4 and the pressure introduction are improved. The mouth 8 may also be coated by thermal spraying to further improve fire resistance.

Further, the shape of the case is not limited to the above-described embodiment, but may be applied to various shapes.

In the above-described embodiment, the first and second fixed electrodes 16 and 17 opposing to both sides of the movable electrode 15 respectively.
However, the present invention is not limited to the differential type pressure sensor, and is of course applicable to a one-sided capacitive pressure sensor having a movable electrode and a fixed electrode. is there.

In the above embodiment, the spacer portions 16d and 17d are provided integrally with the first and second fixed electrodes 16 and 17, however, individual spacers may be provided as in the conventional case.

(Embodiment 2) FIG. 7 is a cross-sectional view of another embodiment of the present invention. In this embodiment, a differential transformer type pressure sensor 2 for detecting the pressure of a fluid such as gas is used.
5 and will be described.

The pressure sensor 25 comprises a case 2 comprising a base 27 integrally formed with a gas pipe connecting pipe 26 and a cover 28 projecting downward and open to the atmosphere.
9 is provided. This pipe 2
A pressure introduction hole 30 communicating with 6 is formed.

At the center of the bottom surface in the base 27, an unduly large negative pressure acts on a pressure chamber formed between the bottom surface and the diaphragm 31 to prevent the diaphragm 31 from being unduly greatly deformed upward. While a plurality of annular convex portions having different diameters are formed in the radial direction as a negative pressure stopper,
An O-ring 32 is provided at a position slightly smaller than the inner diameter of the base 27 on the outer peripheral side to seal the pressure chamber from the atmosphere side.
Has been deployed. The diameter of the O-ring 32 corresponds to the diameter of the peripheral portion of the diaphragm 31. Inside the base 27, a block body 33 whose outer diameter matches the inner diameter of the base is housed.

The block body 33 is made up of the diaphragm 31
The upper peripheral portion in the figure has a protruding shape corresponding to the peripheral portion of the above, and the center is a concave portion, so that the diaphragm 31 can be arranged in the central concave portion. Diaphragm 31
The peripheral portion is sandwiched between the inner surface of the base 27 and the peripheral portion of the block body 33.

The differential transformer 34 provided inside the block body 33 has a spool 35 around which a coil is wound. A sliding body 36 constituting a core is formed in a central through hole of the spool 35 as described later. It has been inserted. The center of the lower part of the sliding body 36 and the spool 35 is
In a state protruding downward from the opening formed in the center of the
The bottom surface of the spool 35 is bonded or screwed to the circuit board 37.

The leaf spring 38 is attached so as to press the lower end of the slide 36 of the differential transformer 34, whereby the upper end of the slide 36 is in contact with the diaphragm 31.

In operation, the diaphragm 31 performs a stroke operation in response to the gas pressure from the pressure introducing hole 30, and the sliding body 36 which forms the core has upper and lower large-diameter sliding contact portions 36a. Spool 35 via 36b
The differential transformer 34 slides on the inner wall and moves.
Outputs the corresponding transformer output. The output of the transformer is applied to a circuit or the like mounted on the circuit board 37 via the output pin of the differential transformer 34, and the gas pressure is detected.

In a conventional differential transformer type pressure sensor,
As shown in FIG. 8, a core that moves in the spool of the differential transformer includes a cylindrical core 40 made of a magnetic material, and a resin plunger 41 having sliding contact surfaces pressed into both ends of the core 40. , 42 are composed of three parts.

In this embodiment, the core moving in the spool 35 of the differential transformer 34 is configured as follows in order to reduce the number of parts and the number of assembling steps to reduce the cost.

That is, a sliding body 36 shown in FIG. 9 having a shape in which a conventional core and plunger are integrated is formed of a resin material.
Are two large-diameter sliding contact portions 3 corresponding to a conventional plunger.
6a and 36b, and a separation portion 36c corresponding to a conventional core between the sliding contact portions 36a and 36b. The separation portion 36c is separated from the inner surface of the spool 35 of the differential transformer 34. A magnetic material is coated on the separated portion 36c by thermal spraying using the same thermal spraying device 23 as in the above-described embodiment to form a core.

As described above, the conventional three parts 40, 41,
Since the core constituted by 42 is formed of a single component by spraying a magnetic material onto the sliding body 36, the number of assembly steps is reduced and the cost is reduced. The accuracy is also stable and the performance is improved.

Further, even for the same sliding member, the linear range of the electromotive force of the differential transformer can be changed by changing the area of the portion where the magnetic material is sprayed.

(Other Embodiments) In the above embodiments, the present invention is applied to a pressure sensor. However, the present invention is not limited to a pressure sensor. May be sprayed to improve the corrosion resistance, or the required material may be coated by spraying on the case or internal parts of a vibration sensor such as a seismic sensor or other sensor devices.

Further, in each of the above embodiments, the object to be sprayed (base material) is a resin material, but is not limited to a resin material, but may be a metal material or another material.

[0052]

As described above, according to the sensor device of the present invention, at least one of the case and the component is coated with a required material by thermal spraying, so that the inexpensive base material constituting the case or the component can be used. By spraying required materials such as various metals, alloys and ceramics, various properties such as heat resistance, abrasion resistance, corrosion resistance, conductivity, dielectric properties, heat insulation properties, etc. can be improved depending on the application. Can be.

Moreover, since the base material can be dealt with by selecting the material to be sprayed, instead of changing the base material according to the application, the base materials constituting the case or the parts can be integrated.

Since the outer surface of the case made of a resin material is coated with a metal material or a ceramic material by thermal spraying, fire resistance can be ensured in an inexpensive resin case.

Further, in the capacitance type pressure sensor device, an electrode plate can be formed by spraying a conductive material on a resin member, and by changing the sprayed area by masking at the time of spraying, the electrode area, and thus the electrode area, In addition, the capacitance can be changed, and the plate-shaped member has a spacer portion formed integrally with the resin material at a peripheral portion thereof, so that compared to a case where electrodes and spacers are separately provided, Assembly man-hours can be reduced.

Further, in the differential transformer type pressure sensor device, the sliding body that slides on the inner surface of the spool is made of a resin material, and the magnetic material is sprayed on the separated portion of the sliding body to form the core, so that the cost is low. The core can be constituted by a single component made of a simple resin material, and thus the number of assembly steps can be reduced and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a pressure sensor according to the present invention.

FIG. 2 is a longitudinal sectional view of FIG.

FIG. 3 is an exploded perspective view of the sensor unit of FIG. 2;

FIG. 4 is a schematic view for explaining a thermal spraying step.

FIG. 5 is an enlarged view of section A in FIG. 2;

FIG. 6 is a diagram showing a fixed electrode according to another embodiment of the present invention.

FIG. 7 is a sectional view of a pressure sensor according to another embodiment of the present invention.

FIG. 8 is a diagram showing a core of a conventional example.

FIG. 9 is a view showing the core of FIG. 7;

[Explanation of symbols]

 4, 29 case 15 movable electrode 16, 17 first and second fixed electrodes 23 thermal spraying device 34 differential transformer 35 spool 36 sliding body

Claims (5)

[Claims] 1. A sensor device comprising a case in which components are stored therein, wherein at least one of the case and the components is coated with a required material by thermal spraying. 2. The sensor device according to claim 1, wherein the outer surface of the case made of a resin material is coated with a metal material or a ceramic material as the required material by thermal spraying. 3. A capacitance type sensor device for detecting a pressure based on a capacitance between opposing electrodes housed in a case, wherein a member made of a resin material has 3. The sensor device according to claim 1, wherein the electrode is formed by coating a conductive material as a material by thermal spraying. 4. The sensor device according to claim 3, wherein the plate-shaped member has a spacer portion formed integrally with the resin material at a peripheral portion thereof. 5. A differential transformer type sensor device for detecting pressure based on an output of a differential transformer, wherein a sliding body that slides on an inner surface of a spool is made of a resin material, and the sliding body is A sliding portion that slides on the inner surface of the spool and a separating portion that is separated from the inner surface of the spool;
3. The sensor device according to claim 1, wherein the core is formed by spraying a magnetic material as the required material onto the separated portion by thermal spraying.