JPS59171826A - Temperature compensator for electrostatic capacitance type pressure sensor - Google Patents

Abstract

PURPOSE:To simplify the temperature compensation by setting a compound temperature coefficient of a housing for supporting a mobile electrode and a diaphragm and a temperature doefficient of a spacer between a fixed electrode member and the housing to be almost equal. CONSTITUTION:A diaphragm 2 supporting an mobile electrode 3 by soldering is fixed on a housing 1 made of a metal material. A ring-shaped spacer 4 made of a resin material is fixed on the housing 1 with a screw 5 while an iron plate 6 as a fixed electrode is fixed with a screw 7 as facing the mobile electrode 3. A pipe 8 as a pressure feed/discharge port is screwed and supported on the housing 1. A compound temperature coefficient of the housing 1 and the diaphragm 2 and the temperature coefficient of the spacer 4 are set to be roughly equal by the selection of material thereby reducing influence due to temperature changes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature compensation bag for a capacitive pressure sensor.

In a capacitive pressure sensor, a diaphragm that supports a movable electrode and a fixed electrode support member that supports a fixed surface are arranged in a housing, and the diaphragm is made of metal such as phosphor bronze. .

The metal diaphragm shows good linearity with respect to pressure, but the humidity coefficient is very large, especially at zero pressure.
, the disadvantage was that there were large fluctuations in the output.

Conventionally, in order to compensate for this, the structure of the sensor body has become complicated and large, or the sensor output is processed within a detection circuit that inputs it, so the sensor body and the detection circuit have to be considered separately. However, there were drawbacks such as a loss of compatibility between the sensors and the main body.

SUMMARY OF THE INVENTION An object of the present invention is to alleviate the drawbacks of the conventional devices described above and to provide a temperature compensation device having a simple structure of a capacitive pressure sensor.

Hereinafter, the present invention will be described in detail based on drawing VC.

First, in FIG. 1, reference numeral 1 denotes a housing made of a metal ion material, which is formed so that a portion 1ai for fixing a diaphragm, which will be described later, is thick to ensure strength against deformation under pressure. 2 is a diaphragm made of phosphor bronze, which is fixed to the nozzle 1 by soldering, and also supports the movable electrode 3 by soldering. Reference numeral 4 denotes an annular spacer made of a plastic material, which is fixed to the housing 1 by a screw 5 made of a plastic material. 6 is an iron plate as a fixed electrode, which is fixed to the spacer 4 by a screw 7 made of plastic (as opposed to the movable electrode 3). 8 is a vibrator as a pressure supply/discharge port, which is screwed and supported by the housing IK. ing.

Therefore, the present invention can improve the housing 1 by selecting the material.
The composite temperature coefficient of the diaphragm 2 and the temperature coefficient of the spacer 4 are set to be approximately equal, and the movable electrode 3 and the iron plate 6 are made to be displaced relative to each other in response to temperature changes, and the temperature coefficient between the two is set to be approximately equal. The interval does not change or the interval changes only slightly.

That is, it is the temperature coefficient of the housing (1) 14, the thickness of its thickened portion (1a) and the diaphragm (3).
TrEj can be simply set from the temperature coefficient of the material, the temperature coefficient and thickness of the spacer (4) material, and the distance between the city poles.

It is preferable that the screw 5 be made of a material that has a humidity coefficient close to that of the housing and the spacer 4, and that the screw 7 be made of a material that has a temperature coefficient that is approximately equal to the temperature coefficient of the spacer 4.

Further, the fixed electrode facing the movable electrode 3 can also be drawn as in the embodiment described later.

Next, in FIG. 2, reference numeral 11 denotes a housing made of plastic, which forms an annular leg portion 11a and a groove portion 1lb, and also extends the pressure supply/discharge D11c in the υj length direction, that is, the diaphragm (to be described later). It is formed in a direction perpendicular to the direction in which pressure is applied, and its size in the height direction is reduced. ] 3 is a base member made of a metal material, which is attached to the housing 1 by a metal screw 14.
1, and is pressure-sealed with the housing 11 by an O-ring 12. Reference numeral 15 designates a diaphragm similar to that of the previous embodiment, which is fixed to the base member 13 by soldering 1, and similarly supports the movable electrode 16.

17 is a fixed electric keyaki support made of glass epoxy or ceramic material! flSvJ, and is fixed to the leg portion 1a with screws 181 made of plastic.

A fixed electrode 19 is supported by a fixed electrode support member 17 so as to face the movable electrode 16. 20 is another fixed room Q
, and is supported by the fixed electrode support member 17 at the side opposite to the fixed electrode 19 (C).

In this embodiment, the base portion vJ'1 is
3 and the diaphragm 15 and the temperature coefficient of the housing 1 are set to be approximately equal.

That is, it is the humidity coefficient of the base member (13), its thickness, the humidity coefficient of the diaphragm (15) material, the humidity coefficient of the housing (11) U, the height of its legs (11,a), and the electric current. This can be easily set based on the distance between the two points.

For the screws 14, a material with a temperature coefficient 1 similar to that of the housing 11 and the base portion 4213 is selected, and the screws 18
It is preferable to select a material having a temperature coefficient substantially equal to that of the housing 1.

Also, li! The capacitance of the il constant electrodes 19 and 20 is determined to be KWr so that the stray capacitance M of the sensor body can be canceled out within the detection circuit.

Furthermore, the fixed electrode support member 17 of this embodiment. Fixed electrical connection 19
For example, it can be replaced with the iron plate of the previous embodiment.

However, in both embodiments, the housing, pace member, and diaphragm are not limited to metal or plastic materials, and various materials can be used.In particular, the diaphragm can be made of an elastic material (elastic material). It is sufficient if it includes the fabrics etc. to be combined.

As described above, as in the present invention, the composite temperature coefficient of the housing and the diaphragm and the temperature coefficient of the spacer, or the composite humidity coefficient of the base member and the diaphragm and the temperature coefficient of the housing are set to be approximately equal. By doing so, it is possible to provide a complete temperature compensation device for capacitive pressure sensors with a simple structure, and since temperature compensation is performed in one sensor body, each sensor body is compatible with the detection circuit. It is something that you come to have.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing embodiments of the present invention, respectively. 1.11...Housing 1a...
・・・・・・・・・Thickened part 1, 1 a
・・ ・・ ・・ ・・ ・・ ・・ ・・ Footsteps 1
511b......Groove 11c...
・・・・・・・・・Upper feed/discharge port 2.15・・・・
・・・・・・Diaphragm 3.16・・・・・・・・・
・Movable electrode 4・・・・・・・・・・・・・・・Spacer 6・・・・・・・・・・・・・・・ Iron plate (fixed electrode) 12・・・・・・・・・・・・・・・0 ring 13
・・・・・・・・・・・・・・・Heath = +t, material 1
7. Fixed electrode support member 19.20. Fixed electrode patent applicant Copal Takeda Medical Institute Co., Ltd. Procedural amendment (method) ) 1 Indication of the case Patent Application No. 47420 filed in 1982 2 Name of the invention 3 Person making the amendment Patent applicant 4 Date of the amendment order Engraving of the specification (no change in content)

Claims (4)

[Claims] (1) In a capacitive pressure sensor consisting of a diaphragm that supports a movable electrode and is fixed to the housing, and a fixed electrode member that is fixed to the housing so as to face the movable electrode, the diaphragm of the housing is fixed. The fixed electrode member is fixed to the housing via a spacer, and the composite structure of the housing and diaphragm is formed by selecting the material. A temperature compensator characterized in that a temperature coefficient and a temperature coefficient of the spacer are set to be substantially equal. (2) In a capacitive pressure sensor comprising a diaphragm that supports a movable electrode and is fixed to a housing, and a fixed electrode member that is fixed to the housing so as to face the movable electrode, the diaphragm base member is The fixed electrode member is fixed to the housing through the housing, and the fixed electrode member is fixed by the leg part, and the composite temperature of the base member and the diaphragm is controlled by selecting the material. A temperature compensation device characterized in that the coefficient and the temperature coefficient of the nozzling are set to be substantially equal. (3) The temperature compensator for a capacitive pressure sensor according to claim 2, wherein the base member has a thickness that ensures strength that it does not deform under pressure. (4) The temperature compensation device for a capacitive pressure sensor according to claim 2, wherein the housing and the base member are pressure-sealed by a sealing material.