JPH0521806Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure switch that senses pressure changes in fluids such as air, water, oil, etc., and opens and closes electrical circuits.

[Prior Art] A pressure switch that senses changes in fluid pressure is connected to electrical control circuits of various fluid pressure operated devices.
Used for switching solenoid valves, blinking lamps, sounding buzzers, etc. The sensing means of the pressure switch is
The structure is such that a protrusion or rod protrudes from the retainer or pressure-receiving piston in contact with the diaphragm to the opposite side and presses the button (contact piece) of the microswitch to open and close the electric circuit. The means for operating the pressure receiving piston at a predetermined pressure generally has a structure in which the length of a compression spring disposed coaxially with the pressure receiving piston is adjusted using adjustment bolts arranged coaxially.

However, in conventional pressure switches in which the microswitch button is placed on the central axis of each component, the compression spring is placed on the outer periphery to surround the microswitch, resulting in a large overall shape of the pressure switch. . In addition, if the microswitch buttons are placed offset from the center axis of each component, the shape will be larger due to the lateral protrusion of the microswitch, and the balance of forces will likely be lost.
The variation in performance also increases.

Further, in the conventional pressure switch, the button of the microswitch is directly pressed by the protrusion of the pressure receiving piston, so when the fluid pressure increases, the microswitch is subjected to an excessive load and there is a risk of damage.

[Problems to be solved by the invention] In view of the above-mentioned problems, the purpose of the invention is to provide a small and highly reliable pressure switch in which the operating pressure of the micro switch is adjusted by an adjustment bolt that is coaxial with the rod of the pressure receiving piston. Our goal is to provide the following.

Another object of the present invention is to provide a pressure switch in which the microswitch does not receive excessive load from the pressure receiving piston.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention is such that a holder having a U-shaped cross section that supports a spring between it and a pressure receiving piston fitted into one end of the housing slides into the housing. A rod supported at the center of the pressure receiving piston has a holder that penetrates the wall at one end and can come into contact with a micro switch disposed in the center of the housing, and a rod at the other end of the housing that is coaxial with the rod. The screwed adjustment bolt is abutted against the other end wall of the holder.

[Operation] When the pressure in the pressure chamber 4 exceeds a predetermined value, the pressure receiving piston 6 moves, the rod 31 is pushed through the spring 9, the button 16a of the micro switch 17 is pushed, and the circuit is opened and closed. Since the rod 31 operates under the load of the spring 9, an excessive load on the button 16a is avoided. An excessive stroke of the pressure receiving piston 6 is prevented by a pin 10 of the housing 14 that projects into the annular groove 12 of the pressure receiving piston 6.

The spring 13 interposed between the holder 15 and the pressure receiving piston 5 allows the adjustment bolt 27 screwed into the end wall 14c of the housing 14 to be connected to the end wall 15b of the holder 15.
It is adjusted according to the Since the adjustment bolt 27 is disposed coaxially with the rod 31 supported at the center of the pressure receiving piston 6, the adjustment operation of the holder 15 is smooth and high control accuracy can be obtained. Since the micro switch 17 is disposed between the coaxial rod 31 and the adjustment bolt 27, the operation is smooth.

[Embodiment of the invention] Fig. 1 is a front sectional view of a pressure switch according to the invention, and Fig. 2 is a side sectional view of the same. The pressure switch has a housing 14 whose lower half has a cylindrical shape and a cup-shaped housing 3, which are coupled together with a diaphragm 5 sandwiched between them, to form a pressure chamber 4 into which fluid pressure is introduced from an inlet 2. Ru. A retainer or pressure receiving piston 6 is slidably fitted into the cylindrical portion of the housing 14 and overlapped with the diaphragm 5 .
The stroke of the pressure receiving piston 6 is limited by a pin 10 that projects from the housing 14 into an annular groove 12 provided on the circumferential surface of the pressure receiving piston 6. A cylindrical portion 7 is integrally formed at the center of the pressure receiving piston 6, and a guide tube 8 is press-fitted and fixed into this. Guide tube 8 is holder 1
5 in a slidable manner. A spring 9 and a rod 31 are inserted into and supported by the guide tube 8, and the rod 31 is brought close enough to come into contact with the button 16a of the micro switch 17.

The holder 15 is slidably fitted inside the housing 14 and supports the spring 13 between it and the pressure receiving piston 6. While the lower end wall of the holder 15 has a disk shape, the upper end has a U-shaped cross section to avoid intersecting with the microswitch 17. That is, the end wall 14c of the housing 14 is attached to the end of the yoke 15a extending along one end wall of the housing 14.
It is integrally provided with an end wall 15b parallel to the . Adjustment bolt 27 screwed into end wall 14c of housing 14
is abutted against the end wall 15b, thereby adjusting the load on the spring 13.

The microswitch 17 is fixed to the flat peripheral wall 14b of the housing 14 with two bolts 18. The conductive wire 25 connected to the terminal 20 of the microswitch 17 is drawn out from the opening 21 of the peripheral wall 14b.

As shown in FIG. 2, the upper half of the housing 14 has a flattened shape, and an opening is provided in the peripheral wall on the left side in the figure and is closed by a cover plate 26. As shown in FIG. A pair of brackets 24 are integrally formed on the right peripheral wall 14b and protrude from the wall surface.
A cutout groove 22 is provided in the pair of brackets 24.
The conductive wire 25 drawn out from the opening 21 is sandwiched between a pair of brackets 24 and fixed to the peripheral wall 14b of the housing 14 by a cylindrical pin (knock pin) 23 that is elastically engaged with the notch groove 22.

Next, the operation of the pressure switch according to the present invention will be explained. When the fluid pressure in the pressure chamber 4 is low, the pressure receiving piston 6 is pushed down by the force of the spring 13,
The upper edge of the annular groove 12 abuts the pin 10.
When the pressure in the pressure chamber 4 exceeds a predetermined value, the pressure receiving piston 6 is pushed up against the force of the spring 13, the spring 9 inside the guide tube 8 is compressed, the rod 31 strongly hits the button 16a, and the micro switch is activated. 17 is activated. In other words, the conductor 25 is connected to a pair of terminals 20.
An energizing circuit, such as a solenoid valve, connected through the valve is opened and closed. Even if an excessive pressure is applied to the pressure receiving piston 6, the upward movement of the pressure receiving piston 6 is prevented by the pin 10, so that no excessive load is applied to the micro switch 17.

When the pressure in the pressure chamber 4 becomes low, the pressure receiving piston 6 is pushed down by the force of the spring 13, and the rod 31
is released from the button 16a, the button 16a is returned by the force of a spring (not shown), and the operation of the micro switch 17 is changed.

Predetermined stroke of the pressure receiving piston 6 (annular groove 1
button 1 due to the force of spring 9 which bends in the width range of 2)
The characteristics of the spring 9 are preset so that the spring 6a operates. Spring 1 that determines the operating pressure of the pressure receiving piston 6
The load No. 3 is set by the position of the holder 15 by the adjustment bolt 27.

In the embodiment shown in FIG. 3, a step 8a is formed in the middle of the guide cylinder 8 coupled to the pressure receiving piston 6. The spring 9 and the end flange 31a of the rod 31 are inserted into the large diameter cylindrical portion on the inner end side of the stepped portion 8a. The flange 31a is formed into a stepped portion 8a by the force of the spring 9.
is engaged with. If the rod 31a and the spring 9 are assembled in advance and the guide tube 8 is press-fitted and fixed into the cylindrical portion 7 of the pressure receiving piston 6, it is easy to assemble the pressure receiving piston 6 to the housing 14.
It never comes off.

[Effect of the invention] As described above, in the present invention, a holder having a U-shaped cross section that supports a spring between the pressure receiving piston fitted in one end of the housing is slidably supported by the housing, and the center of the pressure receiving piston is A rod supported on the holder passes through one end wall of the holder and can come into contact with a micro switch disposed in the center of the housing, and an adjustment bolt coaxially screwed with the rod on the other end wall of the housing is attached to the other end wall of the holder. The microswitch is fixed to the housing so that it is located inside the holder, which has a U-shaped cross section, so the space inside the housing is effectively used, and as a result, the outer shape of the housing is becomes smaller,
It is lightweight and costs are reduced.

Furthermore, since the microswitch is not pushed directly by the pressure receiving piston but by the rod via the spring, there is no possibility that an excessive load will be applied to the microswitch and cause it to be damaged.

In particular, if a preloaded spring and rod are supported inside the guide cylinder of the pressure receiving piston, the microswitch can be operated reliably with a small stroke of the rod, improving reliability.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a pressure switch according to the present invention, FIG. 2 is a side sectional view of the same, and FIG. 3 is a front sectional view of an operating part of a microswitch according to a partially modified embodiment of the present invention. 3, 14...housing, 4...pressure chamber, 5...
...Diaphragm, 6...Pressure receiving piston, 8...Guide tube, 9, 13...Spring, 15...Holder, 17
... Micro switch, 27 ... Adjustment bolt, 3
1... Rod.

Claims (1)

[Claims for Utility Model Registration] (1) A holder with a U-shaped cross section that supports a spring between a pressure receiving piston fitted to one end of the housing is slidably supported by the housing and is supported at the center of the pressure receiving piston. The rod passes through the end wall of the holder and can come into contact with a micro switch disposed in the center of the housing, and an adjustment bolt coaxially screwed into the other end wall of the housing is attached to the other end wall of the holder. A pressure switch characterized by being abutted. (2) The pressure switch according to claim 1, wherein the rod is fitted into a guide cylinder of a pressure receiving piston and urged toward the microswitch by a spring.