JPS63150640A - Pressure detector - Google Patents

Abstract

PURPOSE:To make a structure simple and inexpensive and to improve durability by converting the pressure of liquid into the extending/contracting motion of a diaphragm and photodetecting light which is enlarged as compared with the momentum. CONSTITUTION:When the diaphragm 2 expands against the force of a disk spring 7 owing to variation in the pressure of the liquid in a pressure receiving chamber 3, a square rod 9 is strained concentrically by a prod 4 to deform elastically in a mountain shape. Then when one mirror surface of the square rod 9 is displaced by DELTAtheta because of the elastic deformation, the angle between a parallel light beam emitted by a light emitting element and a parallel light beam incident on a photodetecting element after being reflected twice by mirror surfaces is 4XDELTAtheta and the ratio of the output of the photodetecting element can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure detector that detects fluid pressure in a fluid circuit such as a refrigerant circuit or a pneumatic circuit. The present invention particularly relates to a pressure sensor that uses fluid pressure as an electrical output.

[Conventional technology]

This type of pressure detector that has been used in the past will be explained with reference to FIG. 5. A bellows 2' provided at the opening of the cylindrical container 1' has a push rod 3' standing upright, and the cylindrical container 1'
A pressure receiving chamber is formed inside the cylindrical container 1' by the bellows 2', and a threaded portion 1'A having a flow path for connection to a fluid circuit (not shown) is formed at one end of the cylindrical container 1'. An abbreviated rotating lever 6' is pivotally connected to a pin 5' provided on a support plate 4' that covers the cylindrical container 1', and one end of the lever 6' is connected to a fixing point 8 via a tension spring 7'. A brush 10' is attached to the other end of the brush 10', which is connected to the resistance element 9' in sliding contact with the resistance element 9'. Lead wires 11' are connected to the resistance element 9' and the brush 10', respectively.

When the bellows 2' expands and contracts in the axial direction of the cylindrical container 1' in response to changes in the fluid pressure in the fluid circuit, the lever 6' rotates around the pin 5' via the thrust rod 3', and the resistance element 9 ′
A blank 10' is in sliding contact with the top of the two lead wires 11'.
This method obtains a pressure value that is converted into an electrical output.

[Problem that the invention seeks to solve]

In the above type of pressure detector, if the precision of the detector is to be improved, the amount of expansion and contraction of the bellows 2' can be increased, but this requires an increase in size, and the pin 5', brush 10, etc.
Since the sliding contact of the brush is made using mechanical parts such as ', there are drawbacks such as deterioration of characteristics and occurrence of hysteresis due to wear of the contact parts.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pressure sensor which eliminates mechanical sliding contact and is simple in construction, inexpensive and durable.

[Means for solving problems]

According to the present invention, the above-mentioned object is achieved by providing a fluid passage connected to a fluid circuit to be detected, a push rod erected, and a tire slam deformable by the fluid pressure in the fluid circuit. a cylindrical box having a pressure receiving chamber formed therein; an intermediate connecting tube fitted externally to the cylindrical box and having a disc spring having a through hole through which the thrust rod passes; and a 90° V-shaped notch in the center of one side. and a square rod having two mirror surfaces forming a shape and two recesses formed at both ends at positions equidistant from the notch, and having an opposite surface and which abuts the thrust rod at the center portion;
A protrusion that abuts the recesses at both ends of the square bar and a clamping part that clamps both ends of the square bar with a small gap are formed, and a light emitting element and a light receiving element are formed in the middle of the square bar. The light-emitting element and the light-receiving element are provided with a circle 0 lid fitted onto the connecting tube, and the light-emitting element and the light-receiving element reflect light beams projected from the light-emitting element onto one of the mirror surfaces sequentially and reflecting on the mirror surface and the other mirror surface. This is achieved by a pressure detection device arranged so as to receive the light.

〔Example〕

The present invention will be described in detail with reference to FIGS. 1 to 4 below.

The pressure detection device of the present invention is constructed by connecting a cylindrical box and a cylindrical lid with an intermediate connecting tube.

The cylindrical box 1 is an airtight container with a diaphragm 2 covering a driftwood channel 1A communicating with a fluid circuit (not shown) at one end and a diaphragm 2 covering the open other end. The pressure receiving chamber 3 is configured by: The shape of the diaphragm 2 can change depending on the fluid pressure in the fluid circuit led into the pressure receiving chamber 3, and a push rod 4 is erected on the main surface of the diaphragm 2 as an indicator to show the degree of deformation. .

The intermediate connecting tube 5 is a cylindrical body that fits onto the cylindrical box 1, and has a through hole 6 at its opening edge through which the thrust rod 4 passes, and a disc spring 7 that biases the diaphragm 2 is attached to the intermediate connecting tube 5. To be crushed.

The cylindrical lid 8 is fitted onto the intermediate connecting cylinder 5, and the cylindrical box 1, the intermediate connecting cylinder 5, and the cylindrical lid 8 have mutually arranged inner and outer circumferential surfaces so that they can be expanded and contracted in the axial direction. A screw thread is formed that screws into the The structure of the cylindrical lid 8 will be described later.

The rectangular rod 9 that serves as the fluid pressure sensing medium of the present invention has two mirror surfaces 1 forming a V-shaped notch with an included angle of 90° in the center of one surface.
0A, 10B, and two recesses 11A, 11B formed at both ends at equidistant positions of the notch.

The notch and recess 11A of the square bar 9.

The push rod 4 is brought into contact with the center portion of the surface opposite to the surface on which 11B is formed. Further, it is convenient to provide a weakening arc-shaped recess 12 at the junction of the two mirror surfaces 10A and 10B in order to reduce the bending strength of the square bar 9.

Inside the cylindrical lid S mentioned above are recesses 11A at both ends of the square rod 9.
, 11B, respectively.

13U3 and both ends of the square bar are provided with 2m long clamping parts 14, 14... (Fig. 2) that clamp both ends of the square bar with a slight gap when the square bar 9 is housed in the pressure detection device. Projections 13A and 13B of cylindrical lid 8 and clamping parts 14 and 14
The free movement of the square rod 9 is restricted by...

In addition, the cylindrical lid 8 has one mirror surface 10A out of two mirror surfaces.
A light-emitting element 15 and a light-receiving element 16 are arranged in parallel so that the light beam projected onto the mirror surface LOA and the other mirror surface 10B sequentially reflects and returns. Reference numeral 17 denotes lead wires connected to the respective elements 15 and 16.

Hereinafter, the operation of the pressure detection device of the present invention will be explained.

When the diaphragm 2 expands against the biasing force of the disc spring 7 due to a change in fluid pressure within the pressure receiving chamber 3, the recesses 11 at both ends of the diaphragm 2 expand.
A, 11B is the protrusion 13A of the cylindrical lid 8.

The square rod 9 supported by 13B receives concentrated stress from the pusher rod 4 on the back side of the notch and undergoes elastic deformation in a figure-eight shape (Fig. 4).When one of the mirror surfaces is displaced by Δθ due to this elastic deformation, The angle θ between the parallel light 118A emitted from the light emitting element 15 initially (FIG. 3) and the parallel light 18B reflected twice on the mirror surface and entering the light receiving element 16 is 4×Δθ, and the output ratio from the light receiving element 16 is Can be made larger. In this case, if the concave part 12 at the bottom of the V-shaped notch is made deep enough, in other words, if the wall thickness of the square bar 9 at the back of the notch is made sufficiently thin, the elastic deformation of the square bar 9 can be absorbed only by the weakened part. , so no distortion occurs on the mirror surfaces 10A and 10B. Furthermore, since the concave portion 12 is formed in the shape of a circular arc, cracks do not occur in the weakened portion due to concentrated loads.

As mentioned above, the cylindrical box 1, the intermediate connecting tube 5 to which the disc spring 7 is attached, and the cylindrical lid 8 supporting the corner n9 are screwed together, so the material and thickness of the disc spring 7 can be changed or the intermediate connecting tube can be changed. By rotating the disc spring 5 and changing the position of the disc spring 7, the amount of displacement of the diaphragm 2 can be easily adjusted. Further, by rotating the cylindrical lid 8, the push rod 4 and the square rod 9 can be brought into contact at a predetermined relative position.

〔Effect of the invention〕

Since the present invention is configured as described above, the fluid pressure to be detected is converted into an extensional movement of a diaphragm, and this movement is converted into elastic deformation of a rectangular rod having two orthogonal mirror surfaces, thereby converting parallel light rays from a light emitting element into By sequentially reflecting the light on two mirror surfaces, the parallel light beams entering the light receiving element are magnified compared to the amount of movement of the diaphragm and received. Since the output ratio of the light-receiving element can be increased in this manner, the amount of movement of the diaphragm may be small, and therefore the device can be made smaller and its durability is increased.

In addition, unlike conventional devices, there is no mechanically active part, so there is no hysteresis, and since the retaining members of the disc spring and the square bar are connected in a threaded manner, it is possible to provide an inexpensive pressure detection device that is easy to adjust. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the pressure detection device according to the present invention, FIG. 2 is a plan view taken along the line ■-■ in FIG. 1, and FIG.
4 and 4 are schematic diagrams showing the detection principle of the present invention, and FIG. 5 is a sectional view showing a conventional pressure detection device. 1... Cylindrical box, 1A... Fluid flow path, 2...
...Diaphragm, 3...Pressure receiving chamber. 4... Push rod, 5... Intermediate connection tube, 6...
・Through hole, 7... Belleville spring, 8... Circle eJ lid, 9... Square bar, 10A, 10[3...
mirror surface, 11A, fin... recess, 12... recessed part, 13A, 13B... protrusion, 14...
- Holding part, 15... Light emitting element, 16... Light receiving element. Fig. 2-3 Fig. 4 q' A Prior art Fig. 5

Claims (1)

[Claims] 1. A fluid passageway (1A) communicating with a fluid circuit to be detected, a thrust rod (4) provided upright, and a diaphragm (2) deformable by the fluid pressure in the fluid circuit. A cylindrical box (1) in which a sealed pressure receiving chamber (3) is formed, and a through hole (6) through which the thrust rod (4) passes.
an intermediate connecting cylinder (5) which is fitted onto the cylindrical box (1) and is equipped with a disc spring (7) having a disc spring (7); ) and two recesses (11A, 11B) formed at both ends at positions equidistant from the notch, and a square rod (9) that abuts the push rod (4) at the center of the opposite surface. , protrusions (13A, 13B) that abut the recesses (11A, 11B) at both ends of the square bar (9), and clamping parts (13A, 13B) that clamp both ends of the square bar with a small gap between them. 14) and a cylindrical lid (8) having a light emitting element (15) and a light receiving element (16) and fitted onto the intermediate connecting tube (5), the light emitting element and the light receiving element The pressure detection device is arranged so that a light beam projected from a light emitting element onto one of the mirror surfaces is sequentially reflected on the mirror surface and the other mirror surface, and is received by the light receiving element. 2. The pressure detection device according to claim 1, wherein a weakening arc-shaped recess (12) is formed at the joint of the two mirror surfaces (10A, 10B) of the square bar (9). 3. The pressure detection device according to claim 1, wherein the cylindrical box (1) and the intermediate connecting tube (5) and the intermediate connecting tube (5) and the cylindrical lid (8) are screwed together, respectively.