JPS6015095B2 - pressure switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure switch device, and more particularly to a pressure switch device that makes it possible to correct the contact position of a movable contact with a fixed contact in response to ambient temperature.

2. Description of the Related Art Conventionally, a pressure switch device has been proposed in which a movable contact operated by a diaphragm pressure plate driven in accordance with a signal pressure is brought into contact with a fixed contact or not, thereby controlling the operation of a solenoid valve device or the like.

However, in conventional devices of this type, especially in those where the body, pressure plate, etc. of the pressure switch device are made of resin members, each member including the diaphragm member is affected by the ambient temperature. As a result of thermal expansion or contraction,
This has the disadvantage that the switch operating pressure changes and the switch cannot be guaranteed to operate at the desired time. That is, as a result of the thermal mass tensioning and contraction of each part, the signal pressure receiving area changes, and in addition, the biasing force of the spring that biases the diaphragm plate to the set position changes, resulting in a disadvantage that the switch operating pressure changes. there were.
SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a new pressure switch device which eliminates the disadvantages of the slave device described above, and in particular uses temperature sensing means to correct and change the contact operating position between the movable and fixed contacts.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a pressure switch device 1 showing an embodiment of the present invention has first and second bodies 11 and 12 made of resin that are fixed to each other by ultrasonic welding or the like, and a second body 12. A cover [3] is fixed to the.

A diaphragm plate made of a diaphragm member 15 whose outer periphery is sandwiched between the bodies 11 and 12 and whose inner periphery is held by a resin pressure plate 14 is disposed inside both bodies, thereby applying signal member pressure inside both bodies. room 16
and an atmospheric pressure chamber 17. A pair of screws 18 and 19 are screwed into the second body 12.

The screw 18 is screwed into the second body 12 via the fixing member 20, so that one end of the fixed contact 21 is held between the second body 12 and the second fixing member 20, and the fixing part village 20 and the screw 18 are connected to each other. One end of the movable contact 22 is held between the heads. Both the contacts 21 and 22 are connected to lead wires 23 and 24, respectively, and the lead wires are connected to an exhaust gas control device, for example, a solenoid valve device for operating a valve device for controlling the supply of secondary air to an exhaust manifold. ing. The movable contact 22 is formed, for example, by a leaf spring, and its free end 26 is connected to the fixed contact 21 by an extension shoulder 25 of the pressure plate 14 passing through the contact 22 when the pressure plate 14 is in the position shown. contact, thus forming a normally closed switch. The other end of the spring 28, which is disposed in the signal negative pressure chamber 16 and has one end locked to the retainer 27, is locked to the pressure plate 14. They are stationed at the locations shown to assist in this.

The position of the retainer 27 can be adjusted by three adjustment screws screwed into the first body 11 via a silicone seal member 29, so that the biasing force of the spring 28 can be adjusted. The signal negative pressure chamber 16 is connected to, for example, a Kurumado intake manifold via a boat 31 formed in the first body 11. Therefore, when the negative pressure of the intake manifold overcomes the biasing force of the spring 28,
Move the diaphragm plate to the left in Figure 1.

Note that a filter 32 may be provided in the second body 12. In the pressure switch device as described above, bodies 1 2
1, 12, pressure plate 14, and the like are made of resin such as Duracon, each of these parts expands as the ambient temperature rises.

This expansion increases the axial length of the pressure switch device itself, thus reducing the biasing force of the spring 28. 3. At the same time, the length of the pressure switch device itself in the flea direction is increased, and the pressure plate 14 and the diaphragm 15 are expanded.
As a result, the signal negative pressure receiving area formed by the plate 14 and the diaphragm 15 is increased.

The reduction in the urging force of the spring 28 and the increase in the pressure-receiving area 3 result in a reduction in the signal operating pressure that activates the diaphragm plate to separate the movable contact 22 from the fixed contact 21 and perform a switch action, thereby setting the desired setting. No switching action is performed when the signal pressure is introduced. When the ambient temperature falls below the predetermined four values, the above-mentioned parts contract, the spring 28 is compressed, and the pressure receiving area by the diaphragm plate decreases, resulting in an increase in the signal operating pressure that performs the switch action, and the desired Similarly, sometimes there is no switching action. In order to eliminate the above-mentioned disadvantages, in the pressure switch device according to the present invention, a bimetal 33 is provided by the head of the screw 19 described above.

The bimetal 33 is configured such that one end is fixed by a screw 19 and one end contacts a plate-shaped fixed contact 21 having a flange at one end, and the fixed contact 21 can be moved as the bimetal 33 expands and contracts due to changes in ambient temperature. do. That is, when the bimetal 33 senses an increase in the ambient temperature, it moves the fixed contact 21 toward the pressure plate 14, and when it senses a decrease in the ambient temperature, it moves it away from the pressure plate 14. The operation of the bimetal 33 will be described in detail with reference to the attached figures 2A, 28, and 2C.

The bimetal 33 has a first plate 33a having a large coefficient of expansion when sensing high temperatures and a second plate 33b having a large coefficient of expansion when sensing low temperatures, and is arranged as shown in FIG. 2A at room temperature. The tips of the upwardly bent portions of both plates 33a and 33b abut against the fixed contact 21 and position the fixed contact 21, which has an elastic force, so that its tips move downward, and at this time, the tips of the pressure plate 14 and the The movable contact 22 actuated by the plate 14 comes into contact with the fixed contact 21 when the gap between the two bodies 12 is smaller than d. When the bimetal 33 senses a high temperature, the high-temperature expansion side plate 33a expands more and the bimetal 33 moves as shown in FIG. 2B, thereby causing the tip of the fixed contact 21 to move upward.

Therefore, at this time, the switch is operated at the gap d+Δ between the plate 14 and the body 12. On the other hand, when the bimetal 33 senses low temperature, the low temperature expansion side plate 33
b expands further and the bimetal 33 shifts as shown in FIG. 2C. Therefore, the gap d-△ between the plate 14 and the body 12
The switch operates. The pressure switch device as described above is
When the negative pressure in the intake manifold is below a predetermined value, the spring 28 causes the pressure plate 14 to be in the position shown in the first figure, so that the free end 26 of the movable contact 22
is in contact with the fixed contact 21.

Therefore, an electric circuit leading to the electromagnetic valve device and the like is formed.
Now, when the negative pressure in the intake manifold exceeds a predetermined value, the pressure plate 14 moves to the left in FIG. 1 against the spring 28, and the movable support point 22 follows this movement.
When it moves by a predetermined amount, its free end 26 separates from the fixed contact 21 and interrupts the electrical circuit. It is clear that the stroke amount of the pressure plate 14 required for the shutoff is corrected by the bimetal 33, which is the ambient temperature sensing means, as described above. As described in detail above, in the pressure switch device according to the present invention, the body, diaphragm plate, etc. expand and contract due to changes in ambient temperature, which changes the biasing force of the spring that biases the pressure plate. Even if the pressure-receiving area changes, we have provided a means to detect the change in ambient temperature and correct the contact position between the fixed contact and the movable sub-point, so in effect the switch action is completed when Okaichi's signal pressure is introduced. This eliminates the disadvantage that the signal pressure for operating the switch changes depending on the ambient temperature.

Since the present invention is as described above, the movable contact may be supported at both ends instead of being supported at one end as in the embodiment, and may also be disposed on the pressure plate. It should be obvious. Furthermore, it is clear that instead of having the fixed contact and the bimetal as separate structures as in the embodiment, the fixed contact in the embodiment itself may be made of a member having temperature sensing performance, and the fixed contact and the bimetal may be integrally formed. Dew. still,
By appropriately considering the characteristics of the bimetal, the switch operating pressure can be set appropriately according to changes in the ambient temperature.
That is, in addition to setting the switch operating pressure to be constant regardless of changes in ambient temperature as in this embodiment, setting the switch operating pressure to be increased or decreased as the temperature rises is as follows:
It is clear that this can be easily done by determining the controlled device or system that is operated by the pressure switch device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pressure switch device according to the present invention, FIG.
Figures A, 2B, and 2C are partially enlarged views of Figure 1 showing the respective states at room temperature, high temperature, and low temperature. 10... Pressure switch counterfeit, 11, 12...
...Body, 14...Pressure plate, 15...
Diaphragm, 16... Signal pressure chamber, 18, 19
...Screw, 21...Fixed contact, 22.
...Movable contact, 28...Spring, 33...Bimetal. Blind I Figure 2A Figure 2B Figure 2C

Claims (1)

[Claims] 1 A diaphragm plate that is movable within the body according to signal pressure; A fixed contact having one end fixed on the body and the other end being a free end bent toward the diaphragm plate; One end on the body a movable contact which is fixed and whose other end is a free end, and which can be contacted by the free end of the fixed contact in accordance with the operation of the diaphragm plate; and a movable contact whose one end is fixed on the body and whose other end is a free end; A pressure switch device comprising a bimetal whose other end is in contact with the fixed contact near the fixed part to the body and is displaced in response to a sensed temperature to correct the contact operating position between the two contacts.