JPS6185737A - Pressure switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (a) Field of the Invention The present invention provides a pressure switch that detects fluid leakage based on the detection of pressure changes in various fluids such as gas and liquid. More specifically, the present invention relates to a compact and highly sensitive pressure switch that can detect minute pressure changes in fluid.

(b) Background of the Invention Usually, this type of pressure switch detects changes in fluid pressure via a pressure receiving element such as a diaphragm or bellows that is sensitive to changes in fluid pressure.

However, when using a diamond slam as a pressure-receiving element, if the outer diameter is made smaller in order to make the switch smaller, it will not be possible to take a large stroke in the pressure-receiving direction, and there will be a limit to miniaturization. was. Also,
When bellows are used, there is a limit to how thin they can be made from a manufacturing standpoint, and therefore a highly sensitive switch based on soft elastic force cannot be obtained.

By the way, it is worth considering the method of etching the metal bellows to make the plate thinner, but in this case it is difficult to make the plate thickness uniform, and if the plate is made too thin, not only will pinholes occur, but the plate will become thinner. By reducing the thickness, the pressure-receiving part becomes softer, causing variations in the contact position and pressing position with the switch mechanism, resulting in a problem in that performance deteriorates.

(c) Purpose of the Invention Therefore, an object of the present invention is to provide a pressure switch that is compact and can exhibit high sensitivity without impairing the soft elasticity of the bellows.

(d) Summary of the Invention This invention provides corrosion resistance that expands and contracts in response to minute pressure changes in the fluid by setting the outer surface side of the bottomed part of the bottomed cylindrical body as a pressure receiving part and setting the opening side periphery as a fixed part. A bellows is provided, a corrosion-resistant reinforcing plate is fixedly provided on the outer surface of the pressure receiving part of the bellows, and a plunger is provided which acts on the inner surface of the bottomed part of the bellows and advances and retreats in conjunction with the expansion and contraction movement of the bellows. The pressure switch is characterized in that it is provided with an action switch that opens and closes between the contact portions in conjunction with the forward and backward movement of the plunger.

(E) Effects of the Invention According to this invention, by fixing a reinforcing plate to the pressure receiving part of the bellows, the strength of the thin pressure receiving part can be increased, and the other peripheral parts of the bellows that are to be expanded and contracted can be strengthened. Since no rigidity is added, the elastic force is not impaired,
This results in a highly sensitive pressure switch with high strength and high elasticity.

Further, since the plunger interlocking with the bellows is interposed in the internal space of the bellows that expands and contracts, the internal space of the bellows can be effectively utilized and the size can be efficiently reduced.

Furthermore, since this plunger contacts the reinforced inner surface of the pressure-receiving part, even if the reinforcing plate provided on the outer surface of the pressure-receiving part is subject to variations in plate thickness or thermal effects during adhesion, This plunger is almost unaffected by the stroke, providing highly accurate and always stable switching performance.

In general, if you use electrodeposited bellows that can be made extremely thin using a plating method, there will be no variation in the thickness of the bellows, there will be no pinholes, etc., and even minute pressure changes can be accurately detected. Can be used as a highly sensitive pressure switch.

(f) Examples of the invention An embodiment of the present invention will be described in detail below based on the drawings.

The drawings show a pressure switch used for detecting gas leaks from city gas, LPG, etc. In FIGS. It is composed of a plunger 13 that moves up and down in conjunction with the expansion and contraction operations of the plunger 13, and an action switch 14 that is opened and closed in conjunction with the up and down movement of the plunger 13.

The above-mentioned bellows 12 is formed into a cylindrical body with a bottom, and, as is well known, has uneven bent portions 15 formed on its circumferential surface that allow expansion and contraction at regular intervals in the axial direction, and is made of a metal with good corrosion resistance. It is formed by a Ti deposition process (plating method) to a very thin thickness of about 15 to 20 μm.

The center portion of the upper surface of the bellows 12 corresponding to the bottomed portion is set as a pressure receiving surface 16, and a corrosion-resistant and thin metal reinforcing plate 17 is fixed to this pressure receiving portion 16. Thereby, the thin pressure receiving surface 16 has a predetermined strength that does not deform even when subjected to gas pressure.

Further, the bellows 12 has a radially extending flange 18 for fixing on the periphery of the open portion, and the flange 18 is fixed by welding and fixing means described later.

Further, a protective cap 19 and a pressure receiving flange 20 as a pressure receiving unit are disposed around the outer circumference of the bellows 12 described above, and a case 21 for supporting the bellows 12 and the plunger 13 is disposed inside the bellows 12. Ru.

The above-mentioned protective cap 19 is formed into a bottomed cylindrical body that can surround the outer periphery of the bellows 12, and a small-diameter gas supply port 22 IFi is provided in the center of the upper surface corresponding to the bottomed side.
On the periphery of the open side of the bottomed cylinder, there is a protrusion 2 for fixing the cap.
3... are equally divided and protrudingly provided.

Further, the pressure receiving flange 20 has the above-mentioned protrusion 23 on the upper end side.
It is formed into a cylindrical body with 7 flanges 24 for fixing the 1MX main body (
(not shown), extending portions 26 formed by opening openings 25 are provided so as to protrude equally divided in the circumferential direction.

By the way, the bellows 12, metal reinforcing plate 17, protective cap 19 and pressure receiving flange 20 described above are connected to the gas supply port 2.
2, it is suitable to use a metal with good corrosion resistance and airtightness, such as stainless steel.

The flange 18 of the bellows described above is airtightly welded and fixed between the lower end surface of the pressure receiving flange 20 and a retaining plate described later, while being sandwiched from above and below. In this case, the lower end of the pressure receiving 7 flange 20, each set to the same outer diameter, the flange 18 of the bellows, and the outer periphery of the retaining plate 27 are sandwiched from above and below with the flange 18 in the middle. Then, the entire outer peripheral surface of the overlapping portion is fused and joined by laser welding or the like. As a result, the welding and rotating part is airtightly sealed, and there is no fear of gas leakage from the fixing part, and the fixing part is efficiently fixed.

The above-mentioned retaining plate 27 is made of a laser weldable metal material such as stainless steel and has a disc shape.
The inner circumferential portion of the retaining plate 27 is integrally insert-molded and fixed to the outer circumferential stepped portion of the case 21 during resin molding of the case 21, which will be described later. This exposed upper surface side is provided as a seat surface that supports the lower surface side of the flange portion 18 described above.

Further, the case 21 has an upper side interposed in the hollow interior 28 of the bellows 12, and is provided in a small diameter part to shorten the switch length in the pressure receiving direction, and a lower part is provided in a large diameter part for fixing the retaining plate. Resin molded into a stepped cylinder.

By the way, a plunge T-insertion hole 29 is vertically penetrated in the central axis direction of the upper side of the case, and this plunge 1ν insertion hole 2
It has a lower surface recess 30 on the lower surface side communicating with 1,
A base 31 on which an action switch, which will be described later, is mounted is integrally attached to the lower recess 30.

The plunger 13 described above is allowed to move vertically and is inserted into the plunger insertion hole 29, and has a contact 32 at its upper end that can be contacted from the inner surface of the pressure receiving surface 16 of the bellows 12. 32 is provided to protrude from the upper surface of the case 21. In addition, at the lower end, there is a pair of left and right pushers 33 branched on both sides for opening and closing an action switch to be described later.
．． 33 are provided. As a result, the plunger 13 moves up and down in response to the up and down movement of the bellows 12, which expands and contracts in response to gas pressure, and as a result operates an action switch to be described later.

The aforementioned base 31 is fitted and fixed into a lower surface recess 30 of the case 21, which is opened in accordance with the size of the base 31, and locking recesses 34 and 34 are formed on both sides of the base 31. . . is a correspondingly protruding lower surface recess 30.
It is locked and fixed by the locking convex portions 35 inside.

36 is an atmospheric ventilation hole.

An action switch, which will be described later, is formed on the upper surface of the base 31. This action switch 14 is the first
Fixed terminal 37, first fixed terminal 37, and leaf spring body 39
and a biasing spring piece 40, and both fixed terminals 37 and 38 are integrally insert-molded and provided during the resin molding of the base 31, and are provided during the first insert molding attack. - The second fixed terminals 37 and 38 have upper ends protruding from the upper surface of the base 31 and are set as the first and second fixed contacts 37a and 38a, and lower end portions respectively extending vertically from the lower surface of the base 31. , are provided as first and second external terminals 37b and 38b.

Among these, the first fixed contact 37a has an inverted shape and projects toward the upper surface of the base 31, and a non-conductive OFF contact 41 projects from the upper surface of the base 31 facing the L-shaped layered curved piece. It is set up. The second fixed contact 38a has a flat plate shape and projects from the center of the upper surface of the base 31, and locking grooves 42 and 43 for plate springs, which will be described later, are formed on both sides of the contact 38a. On the other side of the upper surface of the base 31, a plate spring locking protrusion 44 is protruded.

Note that these fixed contacts 37a and 38a protrude from a low step 45 on the base 31, and when the base 31 is attached to the case 21, these fixed contacts 37a and 38a
The lower surface recess 30 of the case 21 and the lower step 45 of the base 31
It is located in an internal space 46 surrounded by.

The above-mentioned leaf spring body 39 has a locking opening 4 formed by opening one end.
7 is locked to the above-mentioned plate spring locking protrusion 44, and the other end is set to a movable piece 48 that allows vertical movement using this locking part as a fulcrum, and the above-mentioned first fixed contact 37a and OFF contact 41 located between.

Furthermore, the central part of the leaf spring body 39 has a fixing piece 49 with one end fixed to the leaf spring body 39 and the other end set as a free end, and the free end side of this fixing piece 49 is a second The plate spring main body 39 is fixedly supported on the base 31 by being locked in one of the plate spring locking grooves 42 of the fixed contact 38H. Further, an opening 50 is provided in the adjacent portion on the free end side of this fixed piece 49 by hollowing out the center thereof, and a locking protrusion 5 is provided protrudingly provided on the side edge of this opening 50 on the first fixed contact side.
1.51, biasing spring piece 40 formed in an arc shape
One end is locked, and the other end is locked in a slightly compressed state in the other leaf spring locking groove 43 of the second fixed contact 38a.

As a result, the movable piece 48 side of the leaf spring body 39 is urged into contact with the first fixed contact 37a by the urging force based on the restoring force of the urging spring piece 40.

Then, the pair of left and right pushers 33, 33 of the plunger 13 mentioned above are applied to the plate spring body 39.
They are provided on both sides of the center of the upper surface so that they can be pressed down freely.

When the pressure switch configured as described above is attached to the main body of the m-unit, the bellows 12 is compressed by a predetermined amount under the pressure of the gas, and the plunger 1 is transmitted through the compressed bellows 12.
3 moves downward, and based on this, the lower leaf spring body 39 is pushed down, and the movable piece 48 is turned OFF, away from the first fixed contact 37a.
Used in condition.

If a gas leak occurs while the pressure switch 11 is in use, the first Ill 1 of the gas leak is detected.
In the /e state, the gas pressure on the bellows 12 decreases, and the bellows 12 naturally expands due to its own elastic restoring force in response to this minute pressure change, and the plunger 1
The pressing blade for 3 is released. As a result, the plunger 13 moves upward, and the movable piece 48 also moves upward, so that the first
It comes into contact with the fixed contact 37a, and is turned on by the connection between both fixed contacts 37a and 38a via the movable piece 48. Through this electrical signal, appropriate measures against gas leakage, such as destruction of the lamp or sounding an alarm, are taken from the main body of the lamp.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is an exploded perspective view showing a pressure switch for detecting gas moisture, FIG. 2 is a perspective view showing its appearance, and FIG. FIG. 4 is an enlarged plan view of the action switch.

Claims (1)

[Claims] 1. The outer surface side of the bottomed part of the bottomed cylindrical body is set as a pressure receiving part, the opening side periphery is set as a fixed part, and a corrosion-resistant bellows that expands and contracts in response to minute pressure changes of the fluid, and the outside of the pressure receiving part of the bellows. A corrosion-resistant reinforcing plate fixed on the surface, a plunger that acts on the inner surface of the bottomed part of the bellows and moves forward and backward in conjunction with the expansion and contraction movement of the bellows, and opening and closing between the contact portions in conjunction with the forward and backward movement of the plunger. A pressure switch with an action switch to operate.