JPS633409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure switch, and particularly to a pressure switch suitable for closing the circuit between two different set pressures and opening the circuit at other pressures.

A conventional pressure switch as shown in Japanese Patent Publication No. 47-15666 has the characteristic shown in A in Figure 1 that the circuit opens when the pressure is higher than the set pressure and closes when the pressure is lower than the set pressure, or vice versa as shown in B in Figure 1. Characteristics are common. Therefore, as shown in C in Figure 1, in order to close the circuit between two different set pressures P ₁ and P ₂ ((P ₁ > P ₂ ), and open the circuit at below P ₁ and above P ₂ In order to achieve this, it was necessary to use a pressure switch having characteristics A and a pressure switch having characteristics B described above in series.

Therefore, we recently proposed a pressure switch having the structure shown in FIG. 2 in order to enable a single pressure switch to close the circuit between two different set pressures and open the circuit at other pressures. Second
In the figure, 1 is the joint of the container containing the fluid to be pressure sensed, and 3 is the O-ring 2 attached to the joint 1.
Pressure switch cap connected via 4
1 is a case, and a diaphragm 6 is sandwiched between the case 4 and the cap 3 via a sealing object 5, and a chamber 7 is formed between the diaphragm 6 and the inner surface of the cap 3, into which the pressure-detected fluid enters. 8' is a pressure receiving part provided on the diaphragm 6, 10' is a first movable contact, 11 is a pair of fixed contacts, 12' is a second movable contact, 13' is a spring receiver, and 14' is a low pressure setting spring. , 15' are high pressure setting springs, and the low pressure setting spring 14' presses against the second movable contact 12' via a spring receiver 13'. Further, the high pressure setting spring 15' pushes down the diaphragm 6 via the first movable contact 10' and the pressure receiving part 8', and when the second movable contact 12' is in contact with the first movable contact 10', is adapted to exert its force also on the first movable contact 10'.

Therefore, when the first set pressure P is less than ₁ ,
Since the first movable contact 10' is pushed down and the movement of the second movable contact 12' is restrained by the fixed contact 11, the first movable contact 10' is pushed down by the second movable contact 12'.
It separates from 2' and becomes an open circuit. When the set pressure _P1 is reached, the state shown in FIG. 2 is reached, and the circuit between the fixed contacts 11 is closed. This state is maintained until the second set pressure _P2 , which is greater than _P1 , and when the set pressure _P2 or higher is reached, the diaphragm 6 is activated by the low pressure setting spring 14',
Since the second movable contact 12' rises against the pressure of the high pressure setting spring 15', the second movable contact 12' rises together with the first movable contact 10', and the second movable contact 12'
The fixed contacts 11 are separated from each other, and the circuit between the fixed contacts 11 is opened.

However, according to FIG. 2, since the pressure receiving part 8' acts in the same way when the set pressure is P ₁ and when the set pressure is P ₂ ,
If the area of the pressure receiving part is determined taking into account the sensitivity and responsiveness of the switch at the low pressure side set pressure P ₁ , in order to ensure operation at the high pressure side set pressure P ₂ ,
The spring force of the high pressure setting spring 15' is extremely large, and (1) the wire diameter of the high pressure setting spring 15' must be made considerably larger than that of the low pressure setting spring 14'.

(2) The mounting load of the high pressure setting spring 15' is commensurate with the high pressure setting pressure _P2 , and that load is always applied.

Therefore, as shown in FIG. 2, the case 4 is larger than that of the conventional pressure switch, which is disadvantageous in terms of improvement in the strength of the case material and installation space.

The present invention has been made in view of the above, and its purpose is to provide a small and highly reliable pressure switch that closes between two different set pressures and opens at other pressures. There is a particular thing.

The first feature of the present invention is that the diaphragm detects the pressure of the fluid, the diaphragm has a low-pressure pressure receiving part that receives the force generated by the pressure of the fluid, and the high-pressure pressure receiving part has a smaller pressure receiving area than the low-pressure pressure receiving part. When the pressure received by the low pressure pressure receiving part and the low pressure pressure receiving part is below a first set value, and when the pressure received by the high pressure pressure receiving part is equal to or higher than a second set value, which is greater than the first set value, the circuit is opened. , a contact mechanism that closes at a pressure between the first and second set values, and the second feature is a diaphragm that detects the pressure of the fluid, and a diaphragm that detects the pressure of the fluid. A pressure receiving part for low pressure and a pressure receiving part for high pressure having a smaller pressure receiving area than the pressure receiving part for low pressure are provided, and a first movable contact is provided on the upper surface of the pressure receiving part for low pressure, and a first movable contact is provided on the upper surface of the pressure receiving part for low pressure. A second movable contact is provided in the pressure receiving part so as to face a part of the first movable contact, and the low pressure pressure receiving part receives low voltage through an electrically insulated spring receiver integrated with the first movable contact. A setting spring is used to press the diaphragm side, and a high pressure setting spring is used to press the high pressure pressure receiving part toward the diaphragm side, and the movement of the spring receiver toward the diaphragm side is regulated. At the same time, a pair of fixed contacts is provided to face another part of the first movable contact, and when the first movable contact is in contact with the fixed contacts, the second movable contact is connected to the first movable contact. The pair of fixed contacts are configured to close if they are in contact, and the third feature is that the configuration includes only a pressure setting spring that presses the high pressure pressure receiving part toward the diaphragm, A stopper is integrally provided in the high pressure receiving part, and the pair of fixed contacts regulates the movement of the high pressure receiving part toward the diaphragm when the stopper hits.

The present invention will be described in detail with reference to the embodiments shown in FIGS. 3, 4, and 7, and FIGS. 5, 6, 8, and 9.

FIG. 3 is a longitudinal sectional view showing one embodiment of the pressure switch of the present invention. In FIG. 3, the relationships among the joint 1, O-ring 2, cap 3, case 4, sealing object 5, diaphragm 6, and chamber 7 are the same as in FIG. 2, and their explanation will be omitted here. 8 is a pressure receiving part for low pressure, and 9 is a pressure receiving part for high pressure. The pressure receiving part 9 for high pressure is provided so as to be able to slide on the inside of the pressure receiving part 8 for low pressure. It is smaller than the pressure receiving area. 10 is a first movable contact provided on the low pressure pressure receiving part 8; 11 is a pair of fixed contacts; 12 is a second movable contact; Some of them are placed facing each other. 13 is a spring receiver for receiving a low pressure setting spring 14, and the spring receiver 13 is integrated with the first movable contact 10.
15 is a high pressure setting spring, 16 is a high pressure setting spring 1
5, and is provided on the upper part of the high-pressure pressure receiving part 9. The spring 15 for high pressure setting is the spring receiver 16
The spring receiver 13, which is integral with the first movable contact 10, is pressed against the fixed contact 11 via the high pressure receiving part 9, the second movable contact 12, and the first movable contact 10. In addition, the movable contact 10,1
2 and fixed contact 11 are made of a conductive material, and as shown in FIG. , the low pressure pressure receiving section 8, the high pressure pressure receiving section 9, and the spring receiver 13 are made of a non-conductive material.

Next, the operation will be explained. When the pressure in the chamber 7 is lower than the set pressure _P1 , the spring force of the low pressure setting spring 14 acts on the fixed contact 11 via the spring receiver 13, and the spring force of the high pressure setting spring 15 acts on the spring receiver 16. , second movable contact 12, first movable contact 1
0, it acts on the fixed contact 11 via the spring receiver 13 that is integrated with the first movable contact 10. In this case, due to the pressure of the fluid to be detected in the chamber 7,
The spring force exerted by the springs 14 and 15 is greater than the force applied to the low-pressure pressure receiving part 8 and the high-pressure pressure receiving part 9 via the diaphragm 6, but the difference is due to the force applied to the spring receiver 13.
The spring force is applied to the fixed contact 11 through the spring, so that no excessive spring force acts on the diaphragm 6. Further, as shown in FIG. 3, since a gap is formed between the fixed contact 11 and the first movable contact 10, the left and right fixed contacts 11 are electrically disconnected. As the pressure in the chamber 7 gradually increases, the force applied to the pressure receiving parts 8 and 9 through the diaphragm 6 increases, and the movable contacts 10 and 12 move upward in the figure together with the pressure receiving parts 8 and 9, and the fixed contact 11 and The gap between the movable contact 10 and the movable contact 10 becomes smaller. When the pressure inside the chamber 7 is between the set pressure P ₁ and the higher set pressure P ₂ , as shown in FIG. The force applied to spring 9 becomes greater than the spring force applied by springs 14 and 15, and first movable contact 10 and fixed contact 11 come into contact. Furthermore, since the pressure receiving area of the high pressure pressure receiving part 9 is smaller than that of the low pressure receiving part 8, the spring force from the high pressure setting spring 15 is greater than the force from the diaphragm 6 that is applied only to the pressure receiving part 9, so the movable contact 12 and 10 remain in contact,
As a result, the circuit between the left and right fixed contacts 11 is electrically closed.

When the pressure inside the chamber 7 becomes higher than P ₂ , as shown in FIG.
Since the force applied to the low-pressure pressure receiving part 8 becomes even larger, the force applied to the low-pressure pressure receiving part 8 becomes sufficiently larger than the force pushing the spring receiver 13 by the low-pressure setting spring 14. However, since the fixed contact 11 acts as a stopper, the movable Contact 10 remains in contact with fixed contact 11 and does not move any further. On the other hand, the force applied to the high pressure pressure receiver 9 is also greater than the force of the high pressure setting spring 15 pushing the spring receiver 16, so as the movable contact 12 moves upward and away from the movable contact 10 which is stopped by the fixed contact 11. reach. Therefore, a gap is created between the movable contacts 10 and 12, and the left and right fixed contacts 11 are electrically opened.

Here, since the pressure receiving area of the high pressure pressure receiving part 9 is made smaller than the pressure receiving area of the low pressure pressure receiving part 8, the chamber 7
Even when the internal pressure is high, the force applied to the pressure receiving part 9 is smaller than that of the pressure receiving part 8. Therefore, a spring with a relatively small spring constant can be used as the high pressure setting spring 15. Note that if the pressure in the chamber 7 rises too much, the upper end surface of the pressure receiving part 9 will close to the stopper 1.
7, further strokes are restricted.

As described above, according to the embodiment of the present invention, it is possible to provide a pressure switch that closes between two different set pressures P ₁ and P ₂ and opens at other pressures, and also has a high pressure setting spring. 15 having a relatively small spring constant can be used, making it possible to downsize the pressure switch and improve reliability accordingly.

FIG. 7 is a longitudinal cross-sectional view showing another embodiment of the present invention, in which the same parts as in FIG. 3 are designated by the same reference numerals, and their explanation will be omitted here. In FIG. 7, a stopper 18 corresponding to the fixed contact 11 is integrally provided in the high pressure pressure receiving part 9 having a spring receiver 16, and a spring receiver 13 and a low pressure setting spring are integrally provided in the first movable contact 10 in FIG. 14 has been abolished.

According to FIG. 7, the pressure inside the chamber 7 is the set pressure P ₁
In the following cases, the spring force of the high pressure setting spring 15 is greater than the force applied to the pressure receiving parts 8 and 9 via the diaphragm 6, so the stopper 18
, so that excessive spring force from the spring 15 does not act on the diaphragm 6. Further, in this state, as shown in FIG. 7, the movable contact 10 and the fixed contact 11 are separated, and there is an open circuit between the left and right fixed contacts 11.

Next, if the pressure in chamber 7 is between P ₁ and P ₂ ,
The force applied to the pressure receiving parts 8 and 9 becomes larger than the spring force of the spring 15, and the stopper 18 moves away from the fixed contact 11 and the movable contact 10 comes into contact with the fixed contact 11, as shown in FIG. Furthermore, since the spring force pushed by the spring 15 is greater than the force applied from the diaphragm 6 only to the pressure receiving part 9, the movable contacts 10 and 12 remain in contact, and a circuit is closed between the left and right fixed contacts 11.

When the pressure in chamber 7 exceeds P ₂ , movable contact 1
0 cannot move due to the fixed contact 11,
Moreover, since the force applied to the pressure receiving part 9 is greater than the spring force of the spring 15, as shown in FIG.
Only the pressure receiving part 9 moves further upward in the figure, the movable contact 12 separates from the movable contact 10, and the left and right fixed contacts 11 are opened.

Here, the spring characteristics of the high pressure setting spring 15 are determined to correspond to the sum of the pressure receiving areas of the pressure receiving parts 8 and 9 as a low pressure setting spring, and the setting of the high pressure _P2 is determined by the pressure receiving area of the high pressure receiving part 9. This is done by changing the area.

According to FIG. 7, as in FIG. 3, the pressure switch can be configured to close between two different set pressures P ₁ and P ₂ and open at other pressures, and the pressure setting spring is Since only one piece is required, further miniaturization becomes possible.

As explained above, according to the present invention, the circuit can be closed between two different set pressures, and the circuit can be opened at other pressures, and moreover, it is possible to create a pressure switch that is small and highly reliable. effective.

[Brief explanation of the drawing]

Figure 1 shows the opening and closing characteristics of three types of pressure switches.
FIG. 2 is a vertical cross-sectional view of a pressure switch that the applicant of the present invention is currently prototyping, FIG. 3 is a vertical cross-sectional view showing an embodiment of the pressure switch of the present invention, and FIG. A perspective view showing the shape of the first movable contact, the fifth
6 is a longitudinal sectional view showing different operating states of the pressure switch of FIG. 3, FIG. 7 is a longitudinal sectional view showing another embodiment of the present invention, and FIGS. FIG. 3 is a vertical sectional view showing different operating states of the pressure switch of FIG. 3... Cap, 4... Case, 6... Diaphragm, 7... Chamber, 8... Low pressure pressure receiving part, 9...
High pressure pressure receiving part, 10... first movable contact, 11...
Fixed contact, 12... Second movable contact, 13, 16...
...Spring receiver, 14...Low pressure setting spring, 15...
High pressure setting springs, 17, 18... stoppers.

Claims (1)

[Scope of Claims] 1. A diaphragm that detects the pressure of a fluid, a low-pressure pressure receiving part that receives a force generated by the pressure of the fluid on the diaphragm, and a high-pressure pressure receiving part that has a smaller pressure receiving area than the low-pressure pressure receiving part. and opens when the pressure received by the low-pressure pressure receiving part is below a first set value and when the pressure received by the high-pressure pressure receiving part is equal to or higher than a second set value, which is greater than the first set value; A pressure switch characterized in that it has a contact mechanism that closes at a pressure between the first and second set values. 2. A diaphragm that detects the pressure of the fluid, a low-pressure pressure receiving part that receives the force generated by the pressure of the fluid on the diaphragm, a high-pressure pressure receiving part that has a smaller pressure receiving area than the low-pressure pressure receiving part, and the low-pressure A first movable contact provided on the upper surface of the pressure receiving part, a second movable contact provided on the high voltage pressure receiving part so as to face a part of the first movable contact, and an electric contact integrated with the first movable contact. a spring receiver that is electrically insulated; a low pressure setting spring that presses the low pressure pressure receiving part toward the diaphragm side through the spring receiver; and a high pressure setting spring that presses the high pressure pressure receiving part toward the diaphragm side; a pair of fixed contacts that regulate movement of the spring receiver toward the diaphragm and are provided to face another part of the first movable contact, the first movable contact and the second movable contact; A pressure switch characterized in that when the first movable contact and the fixed contact contact each other, the pair of fixed contacts electrically close the circuit. 3. A diaphragm that detects the pressure of the fluid to be detected, a low-pressure pressure receiving part that receives the force generated by the pressure of the fluid on the diaphragm, a high-pressure pressure receiving part that has a smaller pressure receiving area than the low-pressure pressure receiving part, and the low-pressure a first movable contact provided on the top surface of the pressure receiving part;
a second movable contact provided on the high-pressure pressure receiving part so as to face a part of the first movable contact; a pressure setting spring that presses the high-pressure pressure receiving part toward the diaphragm; and the high-pressure pressure receiving part. a pair of fixed contacts provided so as to be opposed to the other part of the first movable contact, and a stopper provided integrally with the contact member regulates the movement of the high pressure pressure receiving portion toward the diaphragm side; The first movable contact and the second movable contact are in contact with each other, and when the first movable contact and the fixed contact are in contact with each other, the pair of fixed contacts are electrically closed. pressure switch.