JP2831695B2 - Small pressure switch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized pressure switch used for detecting an internal pressure of a system in a refrigerating apparatus or the like to control an operation state.

[Conventional technology]

A pressure switch is used in the refrigeration system to detect when the refrigerant pressure abnormally drops or rises and to shut off the power supply circuit. Such a pressure switch for security is generally configured to receive the pressure of the refrigerant by a pressure responsive body composed of a combination of a diaphragm and a spring means, and to open and close a switch contact via a switch driving member. is there. However, it is generally desirable that such pressure switches be small,
Disc springs are often used as spring means rather than coil springs.

As such a small pressure switch, there is, for example, one configured as shown in FIG. In this pressure switch, the pressure of the refrigerant introduced from the pressure inlet 1a of the lid 1 into the pressure receiving chamber 1b pushes up the diaphragm 3, and the conical spring 6
The contact 8 provided in the switch main body 2 is brought into contact with the other contact 8 ′ via the switch driving member 5 biased and supported by the switch 8. When the pressure of the refrigerant further increases, the pressure reversing plate 4 supporting the diaphragm 3 reverses and pushes up a switch driving rod 7 provided through the switch driving member 5 to change the contact 8 'to the contact 8
It is operated so as to be separated from it.

[Problems to be solved by the invention]

Such a conventional pressure switch has a disadvantage that the contact between the contacts is unstable because the opening and closing operation at the low-pressure side operation point is slow, and chattering occurs particularly in an environment with a lot of vibration.

On the other hand, in order to obtain a pressure switch that does not cause chattering, the present inventors have used a dish-shaped spring incorporated therein, which operates reversely. And the return load was large, and accurate pressure response characteristics could not be obtained. Further, when a dish-shaped spring having a small load difference between the reversal and the return is selected in order to maintain accurate pressure response characteristics, the reversal height is insufficient and chattering cannot be suppressed.

In such circumstances, an object of the present invention is to provide a small-sized pressure switch that has high-precision pressure response characteristics and does not cause chatter. More specifically, the structure of a conventional pressure switch is The purpose of the present invention is to improve chattering while maintaining high-precision pressure response characteristics only by replacing the disc spring without changing.

[Means for solving the problem]

SUMMARY OF THE INVENTION An object of the present invention as described above is to provide a pressure responsive element that receives fluid pressure, a switch driving member that is biased and supported by a dish-shaped reversing spring, and that is driven by the pressure responsive element, and that is driven by the switch driving member. And a switch contact which is separated from and connected to each other, wherein the disc-shaped reversing spring has a perforated bottom plate, the outer diameter of the disc-shaped reversing spring is D, and the diameter of the perforated bottom plate is d. When the diameter of the hole is δ and the height of the dish-shaped reversing spring is H, d is in the range of 0.45D to 0.65D, δ is 0.7d or less, and H is 0.02D to 0.05. D
Can be achieved by a miniature pressure switch characterized by being within the range:

In addition, in such a dish-shaped reversing spring, it is needless to say that the spring strength can be adjusted to a desired value by appropriately selecting the thickness according to the mechanical properties of the spring material used.

(Operation)

The small pressure switch of the present invention incorporating the disc-shaped spring having such a specific shape has a small opening / closing pressure difference at the time of opening / closing operation, is highly sensitive, and operates reliably.

〔Example〕

Hereinafter, an example of the compact pressure switch of the present invention is shown in FIG. 1. However, the present invention is not limited to this example. May be something.

The structure of the example shown in FIG. 1 is exactly the same as that of the pressure switch shown in FIG. 4 except that a disc-shaped reverse spring 9 with a perforated bottom plate is used instead of the disc spring 6. The perforated inverted spring 9 with a perforated bottom plate has a cross-sectional shape as shown in FIG. 2. The outer diameter D is 16 mm, the bottom diameter d is 9 mm, the height H is 0.55 mm, and the hole diameter δ. Is 6mm. Therefore, d = 0.65D, H = 0.034D, and δ = 0.67d.

The load / displacement characteristics of the dish-shaped reversing spring 9 obtained by measuring the movement of the switch driving member 5 in this pressure switch are as shown in FIG. In this figure, the proportion of load difference F (the difference between the inverted start displacement s ₁ and the return start displacement s ₂₎ inversion height for (reversal load f ₁ and the return force f ₂ the difference between) S is known from the prior art In the pressure switch using the disc-shaped spring 6 without the bottom plate, the reversing height S 'in the graph of FIG. In the switch, the average value was improved by about 5%. Such improvement of the reversing height S of the dish-shaped reversing spring 9 was sufficiently effective to prevent chattering between the contacts.

〔The invention's effect〕

The compact pressure switch of the present invention incorporates a dish-shaped reversing spring of a specific shape, so that the shape and performance of the other members are completely the same, the vibration resistance is improved, and the occurrence of chattering can be improved. It is a thing.

Therefore, the advantage that the sensitivity of the switch is stabilized and the life of the contact is significantly extended is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a compact pressure switch of the present invention, FIG. 2 is a cross-sectional view of a disc-shaped reversing spring used in the switch, FIG. 3 is a graph showing load / displacement characteristics of the disc-shaped reversing spring. FIG. 4 is a cross-sectional view of an example of a conventional compact pressure switch, and FIG. 5 is a graph showing the load / displacement characteristics of a disc-shaped spring used in the conventional compact pressure switch. DESCRIPTION OF SYMBOLS 1 ... lid, 2 ... switch body, 3 ... diaphragm, 4 ... pressure reversal plate, 5 ... switch drive member, 6 ...
… Disc spring, 7… Switch drive rod, 8,8 ′ …… Contact point,
9 ... dish-shaped inverted spring with perforated bottom plate.

Claims (1)

(57) [Claims] 1. A pressure responsive body receiving a fluid pressure, a switch driving member urged and supported by a dish-shaped reversing spring and driven by the pressure responsive body, and driven by the switch driving member to be separated from each other. A pressure switch provided with switch contacts, wherein the dish-shaped reversing spring has a perforated bottom plate, the outer diameter of the disc-shaped reversing spring is D, the diameter of the perforated bottom plate is d, and the diameter of the hole is Is δ and the height of the dish-shaped reversing spring is H, d is in the range of 0.45D to 0.65D, and δ is 0.7d
A compact pressure switch, wherein H is in the range of 0.02D to 0.05D.