JPH06334198A - Mounting structure of pressure sensor - Google Patents

Abstract

PURPOSE:To make it possible to mount a pressure sensor without affecting adversely the characteristics of the pressure sensor by interposing an elastic member between the main body of the pressure sensor and a stopper or a pressure sensor port. CONSTITUTION:The main body 9 of a pressure sensor inserted into a pressure sensor port 8 is fixed with a stopper 10 for drop out prevention. The spot at which the pressure sensor main body 9 comes in contact with the pressure sensor port 8, is sealed with a shaft seal 11 which envelops the pressure sensor main body 9 around its central shaft. An elastic member 12, which is elastically deformed by a specified amount, is interposed between an end face 9a which crosses the central shaft of the pressure sensor main body 9 and a seat surface 8a of the pressure sensor port 8 which faces the end face. Therefore, the specified amount of elastic deformation of the elastic member allows the pressure sensor main body to be pressed with the stopper or the pressure sensor port to be pressed with a proper amount of force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor mounting structure.

[0002]

2. Description of the Related Art When the pressure of a fluid such as gas or liquid is measured using a diaphragm type pressure sensor, a seal is provided between the pressure sensor and the pressure sensor port in order to prevent the fluid from leaking.

As a method of this sealing, a shaft seal 3 surrounding the central axis of the pressure sensor main body 1 between the main body 1 of the pressure sensor and the pressure sensor port 2 as shown in FIG.
7, a method of interposing a seal member 4 between the end face 1a of the pressure sensor main body 1 as shown in FIG. 7 orthogonal to the central axis thereof and the seat face 2a of the pressure sensor port 2 facing the end face 1a. There is a method of welding the pressure sensor main body 1 and the pressure sensor port 2 as a joint as shown in FIG. 8 to perform pressure sealing.

Among the above-mentioned sealing methods, the sealing method using the shaft seal 3, which has the advantage of being particularly resistant to heat cycle and capable of sealing without tightening, is mainly used. The pressure sensor body 1 is
It is fixed to the pressure sensor port 2 by a method of locking the retaining ring 6 to the pressure sensor port 2 as shown in FIG. 9 or a method of screwing the holding screw 7 to the pressure sensor port 2 as shown in FIG.

[0005]

However, according to the conventional fixing method using the holding screw 7, when the holding screw 7 is pushed in to protect the pressure sensor from disturbances such as vibration and shock in the field, the pressure sensor becomes large. A force is applied and strain is generated, which adversely affects the characteristics of the pressure sensor. In addition, there is a problem in that the characteristics of the pressure sensor change with time as the joint becomes more familiar. Even when the pressing screw 7 is pushed in with a small force to avoid such an inconvenience, the pressure sensor port 2 and the pressure sensor main body 1 are made of different materials, and there is often a difference in the coefficient of thermal expansion. The tightening force applied to the pressure sensor may change, which may affect the characteristics of the pressure sensor.

According to the latter method using the retaining ring 6, when the pressure largely fluctuates or the positive and negative pressures are repeatedly applied, the pressure sensor body 1 and the pressure sensor port 2 have a play in the direction of their central axes. Occurs, which adversely affects the characteristics of the pressure sensor.

Therefore, an object of the present invention is to provide a mounting means for a pressure sensor which does not adversely affect the characteristics of the pressure sensor.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a pressure sensor body inserted into a pressure sensor port, which is locked by a stopper for preventing the pressure sensor body from falling off. The portion in contact with the pressure sensor port is sealed by a shaft seal surrounding the main body of the pressure sensor around its central axis, and the pressure sensor port facing the end surface orthogonal to the central axis of the main body of the pressure sensor and the end surface. And a pressure sensor mounting structure in which an elastic member elastically deformed by a predetermined amount is interposed between the pressure sensor and the pressure sensor.

[0009]

The function of the shaft seal is to prevent the fluid from leaking out by sealing between the body of the pressure sensor and the pressure sensor port.

An elastic member is interposed between the main body of the pressure sensor and the pressure sensor port, and this elastically deforms by a predetermined amount to press the pressure sensor main body against the pressure sensor port with an appropriate force.

Therefore, it is possible to reduce the initial characteristic change of the pressure sensor and the characteristic change over time.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 As shown in FIG. 1, a main body 9 of a pressure sensor inserted in a pressure sensor port 8 is locked by a stopper 10 for preventing it from falling off, and the main body 9 of the pressure sensor is attached to the pressure sensor port 8 described above. Is sealed by a shaft seal 11 surrounding the main body 9 of the pressure sensor around its central axis, and the end surface 9a of the main body 9 of the pressure sensor orthogonal to the central axis and the pressure sensor facing the end surface 9a. Seat surface 8a of the support 8
An elastic member 12 that is elastically deformed by a predetermined amount is interposed between and.

The pressure sensor is a diaphragm type, and its main body 9 has a substantially cylindrical shape. Reference numeral 15 indicates a lead wire for extracting a signal from the pressure sensor.
The pressure sensor port 8 is a mounting portion for a pressure sensor provided at a location of the pneumatic hydraulic device or the like for measuring pressure, and is provided integrally with the pneumatic hydraulic device or the like, or as shown in FIG. It is configured as a joint 13 that can be mounted on.

The pressure sensor port 8 is provided with a cavity 8b for accommodating the body 9 of the pressure sensor.
A fluid introduction path 8c is provided at the back of b. The body 9 of the pressure sensor is inserted into the cavity 8b,
It is locked by a stopper 10 so as not to drop from b. The stopper 10 is, for example, a C-shaped stopper ring, and is inserted into an annular groove 8d provided in the inner peripheral wall of the cavity 8b.

The shaft seal 11, which is an O-ring in this case, is fitted into an annular stepped portion 9b formed at the rear end of the body 9 of the pressure sensor, and is in close contact with the inner peripheral wall surface of the cavity 8b of the pressure sensor port 8, The fluid is prevented from leaking from the pressure sensor port 8 to the outside.

The elastic member 12 is a wave washer as shown in FIG. 3, and is made of a ring-shaped plate rich in elasticity so as to be corrugated a plurality of times in the circumferential direction. In addition to wave washers, disc spring washers can also be used. The elastic member 12
Is inserted between a circular end surface 9a of the main body 9 of the pressure sensor orthogonal to its central axis and a seat surface 8a of the pressure sensor port 8 facing the end surface 9a, and comes into contact with both with a predetermined elastic deformation. is doing.

As a result, the body 9 of the pressure sensor is fixed so as not to move inside the cavity 8b of the pressure sensor port 8. Further, the force for fixing the pressure sensor can be set to a necessary minimum by adjusting the amount of deformation of the elastic member 12, so that the main body 9 of the pressure sensor is stopped with an appropriate force.
Thus, the initial characteristic change of the pressure sensor and the characteristic change over time are reduced.

The pressure sensor can be attached by the following procedure. First, the elastic member 12 made of a wave washer, the seal 11 made of an O-ring, and the pressure sensor main body 9 are sequentially inserted into the cavity 8b of the pressure sensor port 8.

Next, the pressure sensor body 9 is pushed into the cavity 8b, and the stopper 10 is inserted into the cavity 8b. The stopper 10 is fitted in the annular groove 8d in the cavity 8b to prevent the pressure sensor from coming out of the cavity 8b.

When the pressure sensor is assembled in this manner, the elastic member 12 is elastically deformed by a desired amount, and the main body 9 of the pressure sensor is pressed against the stopper 10 with an appropriate amount of force and fixed in a fixed position.

Embodiment 2 As shown in FIG. 4, the stopper 10 is used in this embodiment.
A set screw is used instead of the snap ring. A female screw 13 is provided at the entrance of the cavity 8b of the pressure sensor port 8, and the male screw 14 of the stopper 10 is screwed onto the female screw 13, and the inner surface of the stopper 10 elastically secures the main body 9 of the pressure sensor. It is pressed against the member 12.

Embodiment 3 As shown in FIG. 5, in this embodiment, the elastic member 12 is used.
A compression coil spring is used instead of the washer.
Another cavity 8e following the cavity 8b of the pressure sensor port 8 is provided in the cavity 8b, and a compression coil spring which is an elastic member 12 is inserted into the cavity 8e. This compression coil spring presses the body 9 of the pressure sensor toward the stopper 10 with an appropriate amount of force.

As the stopper 10, a set screw as in the second embodiment can be used.

[0024]

As described above, according to the present invention, the elastic member is interposed between the main body of the pressure sensor and the stopper or the pressure sensor port, and this elastically deforms by a predetermined amount to stop the pressure sensor main body. Since the tool or the pressure sensor port is pressed with an appropriate force, the initial characteristic change of the pressure sensor and the characteristic change over time can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a pressure sensor mounting structure according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a pressure sensor mounting structure together with another example of the pressure sensor port.

FIG. 3 is a perspective view of an example of an elastic member.

FIG. 4 is a vertical sectional view showing another embodiment of the pressure sensor mounting structure.

FIG. 5 is a vertical sectional view showing still another embodiment of the pressure sensor mounting structure.

FIG. 6 is a vertical cross-sectional view showing a sealed state of a conventional pressure sensor.

FIG. 7 is a vertical cross-sectional view showing another example of the sealed state of the conventional pressure sensor.

FIG. 8 is a vertical sectional view showing still another example of the sealed state of the conventional pressure sensor.

FIG. 9 is a vertical cross-sectional view showing a conventional pressure sensor mounting structure.

FIG. 10 is a vertical sectional view showing another example of a conventional pressure sensor mounting structure.

[Explanation of symbols]

 8 ... Pressure sensor port 9 ... Pressure sensor main body 9a, 9c ... End surface of pressure sensor main body 11 ... Shaft seal 12 ... Elastic member

Claims (2)

[Claims] 1. A body of a pressure sensor inserted in a pressure sensor port is locked by a stopper for preventing the pressure sensor from coming off, and a portion where the body of the pressure sensor contacts the pressure sensor port is the body of the pressure sensor. An elastic member elastically deformed by a predetermined amount is interposed between an end surface of the main body of the pressure sensor that is orthogonal to the central axis and the pressure sensor port that faces the end surface and that is sealed by a shaft seal that surrounds the central axis. A pressure sensor mounting structure characterized by being mounted. 2. The mounting structure for a pressure sensor according to claim 1, wherein the elastic member is a wave washer.