JPS642354Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is installed on the high-pressure side of the refrigeration cycle of an automobile cooling system, and when the pressure on the high-pressure side of the refrigeration cycle abnormally increases or decreases,
This invention relates to a two-action pressure switch used to open and stop an electric switch connected to a compressor of a refrigeration cycle.

The conventional pressure switch 1 will be explained based on FIGS. 7 and _8. As shown in FIG. When the outer piston 3 and the inner piston 4 are pushed down against the spring 5, the first movable contacts 6 and 7 come into contact with the fixed contacts 8 and 9. In this case, since the first and second movable contacts 6 and 7 are already connected to the second movable contact 10, the fixed contact 8, the first movable contact 6, the second movable contact 10, the first movable contact 7, and the fixed contact 9 becomes conductive and pressure switch 1 is turned on. Furthermore, when the pressure P' in the pressure chamber 2 increases and becomes larger than the second set pressure _P2 ', the pressure on the diaphragm 11 increases, but the external piston 3 does not fall because it is locked by the fixed contacts 8 and 9. The force acting downward on the diaphragm 11 acts only on the internal piston 4, pushing down the internal piston 4 against the force of the spring 5, and the second movable contact 10 engaged with this internal piston is pushed down. It separates from the first movable contacts 6 and 7, and there is no communication between the fixed contacts 8 and 9, and the switch is turned OFF. However, as soon as the pressure inside the pressure chamber 2 drops below P ₂ ', the switch is turned on. In this way, at the second set pressure P ₂ ', the switch is ON;
Repeated turning off caused chattering and noise, and at the same time the contacts of the switch wore out, resulting in a lack of durability.

In view of these conventional drawbacks, the present invention has created an operating hysteresis in the set pressure on the high pressure side, so that the electric switching part is operated by the elastic force of a coil spring without providing a leaf spring, and a reversing disc is used. A diaphragm is airtightly sandwiched between an upper body and a lower body to provide a pressure chamber inside the upper body, and a diaphragm is placed on the side opposite to the pressure chamber of the diaphragm. In a switch having a piston that moves up and down due to external pressure received through the piston, a second effective pressure receiving area smaller than the effective pressure receiving area of the piston is provided in an annular locking part provided on the upper surface of the piston, and an upper A reversing disk protruding from the lower body is housed so that it can be turned upside down, the piston is housed through a holder so as to be movable up and down with a first spring, and the holder is locked and the piston is held at the bottom of the lower body. A pair of fixed contacts connected to the fixed terminal are fixed to the lower body, and the pair of first movable contacts provided on the lower surface of the piston and the fixed contacts form a first electrical switching section, and from the second spring, which was released and accommodated.
A second electric switching part is formed by the movable contact and the first movable contact, and the second movable contact is directly pushed downward by the downward reversal of the reversal disk into the through hole provided in the center of the piston. It is characterized by having a rod passed through it for cutting off the second electrical switch.

In this way, by utilizing the reversal operation hysteresis of the reversal disk, a third set pressure that is slightly smaller than the second set pressure on the high pressure side is provided, and a gap between the reversal operation and the return operation of the reversal disk is established. By setting an appropriate hysteresis, the switch turns on and off at the second set pressure.
This can prevent the repeated chattering phenomenon.

The embodiment of the present invention will be explained with reference to the drawings.
The upper body has a communication hole 21 in the center of the upper part through which pressure enters, and is fixed to the upper part of the lower body 23 by caulking. A pressure chamber 22 is provided in the upper body by sandwiching the upper body and communicating with the communication hole 21. Reference numeral 23 denotes a lower body made of an insulating material, and a recess 29 is formed at the bottom of a large diameter chamber 27 provided at the center of the upper part of the lower body through a step 28, and a small hole for ventilation is formed in the bottom of this recess. form 30.

Fixed terminals 31 and 32 are fixedly inserted into the lower body in the vertical direction, with the lower ends protruding outside the lower body, and the upper parts bent inward at right angles and protruding into the recessed portion 29 to form fixed contacts 33 and 34. has been formed.
A piston 35 is located below the diaphragm 24 and is housed in the large diameter chamber 27 of the lower body so as to be able to move up and down. On the lower surface of the piston 35, a pair of first movable contacts 36 having a substantially semi-doughnut shape are provided. , 37 are mounted non-rotatably facing each other with an interval 50 between them, and are moved up and down by the pressure acting downwardly on the piston 35 to contact and separate from the fixed contacts 33, 34. It also comes into contact with and separates from the movable contact 48. In this case, the first movable contacts 36 and 37 do not necessarily need to be fixed to the lower surface of the piston 35. A piston is installed on the upper surface of the piston 35 to set a small second effective pressure receiving area that is separate from the first effective pressure receiving area of the piston 35 determined by the shape of the outer circumference of the piston, the shape of the diaphragm, and others. A locking part 3 formed in an annular shape on the inside of the top surface
A reversing disk 39 is housed within the reversing disk 8 so that it can be turned upside down. This reversing disk 39 performs reversing operation at a second set pressure P 2 to be described later which is activated by the second effective pressure receiving area, and then returns to reverse at a third set pressure P ₃ which is slightly smaller than the second set pressure P _{2 .} It has a hysteresis that causes Reference numeral 40 denotes a through hole provided in the center of the piston 35, into which a rod 41 is mounted so as to be movable up and down.

Reference numeral 44 denotes a holder made of an insulating material, which is housed in the recessed part 29 so as to be movable up and down, and is urged from below by a first spring 43. , 34, and the holder 44 cannot rise any further. Further, on the outer periphery of the upper surface of this holder, a second movable contact in the form of a disk is provided in an annular raised part 46 formed higher than the thickness of the fixed contacts 33 and 34, and the second movable contact is elastically pushed upward by a second spring 47. It accommodates 48. The lower end of the rod 41 abuts on the center of the second movable contact 48, and the upper end of the rod 41 is positioned so as to be able to appropriately abut on the center of the reversing disk 39. In this case, the reversing force of the reversing disk 39 is set to be stronger than that of the first spring 43, and the second spring 47 simply acts on the second movable disk 4.
It has enough elasticity to lift 8.

Here, the first movable contacts 36 and 37 and the fixed contact 3
3 and 34, respectively, the first electrical switching section S ₁ on the low voltage side
The first movable contacts 36, 37 and the second movable contact 48 form a second electrical switching section _S2 on the high voltage side.

Next, to explain the operation of this embodiment, FIG. 1 shows a state in which the pressure P in the pressure chamber 22 is smaller than the first set pressure P ₁ on the low pressure side shown in FIG. When the first movable contacts 36, 37 are pushed up through the holder 44 by the elastic force of the holder 43 and separated from the fixed contacts 33, 34, the first electrical switching section _S1 is opened. In this case, the locking collar 45 of the holder 44 is the fixed contact 33 which also serves as a stopper.
34 and cannot move upward any further.

Then, the pressure P in the pressure chamber 22 becomes the first set pressure.
When the pressure is higher than P ₁ and lower than the second set pressure P ₂ on the high pressure side (Fig. 2), the pressure acting on the piston 35 via the diaphragm 24 is equal to the effective pressure receiving area Bcm ² of the piston and the first First set pressure set by spring force (F) kg of spring 43
Since it is larger than P ₁ Kg/cm ² (=F/B), the pair of first movable contacts 36, 3 installed at the bottom of the piston 35
The piston 35 descends until the contact point 7 hits the upper surface of the pair of fixed contacts 33, 34, and the first electrical switching section _S1
Close. Furthermore, since the pressure inside the pressure chamber 22 is less than the second set pressure P ₂ , the reversing disk 39 does not reverse and is convex upward, so the rod 41 is separated from the lower surface of the reversing disk 39. . Therefore, the second movable contact 48 is pushed upward by the force of the second spring 47, and the pair of first movable contacts 36,
37, and the second electrical switching section _S1 is also closed. Therefore, the electric path conducts the fixed contact 33, the first movable contact 36, the second movable contact 48, the first movable contact 37, and the fixed contact 34, and the switch is in the ON state.

Figure 3 shows that the pressure inside the pressure chamber 22 is the second set pressure.
This shows a case where the third set pressure P 3 or _{higher causes the reversal disk 39 to return upward and reverse itself after exceeding P 2 .}
In this state, since the inversion disk 39 is inverted downward, the lower surface of the inversion disk pushes down the rod 41 and also pushes down the second movable contact 48 against the elastic force of the second spring 47. As a result, the second movable contact is separated from the pair of first movable contacts 36, 37, the second electrical switching section _S2 is opened, and the switch is turned off.
This is the OFF state.

The present invention having the above configuration has the following effects.

The second set pressure _P2 on the high pressure side is set by the reversing pressure of the reversing disc, and the third set pressure _P3 , which is smaller than this second set pressure, is set by the return reversing pressure of the reversing disc. In addition, the first
The set pressure _P1 is set based on the effective pressure receiving area of the piston and the load of the first spring, and each set pressure is independent, making pressure adjustment easy.

For operation on the high voltage side, a reversing disk is set in the pressure receiving part via a diaphragm, and the operational hysteresis due to the reversing and returning operation of this reversing disk is directly applied to the electric switching section on the high voltage side. The response of the switch is good, and the timing of activation of the electric switch is accurate.

By using a reversing disk with a smaller diameter than the piston, a hysteresis is applied to the reversing and returning of the reversing disk, eliminating the need for complex functions such as a snap action for setting the hysteresis on the electrical contact side, and simplifying the parts. and miniaturization.

Since the operating hysteresis caused by the reversing and returning operations of the reversing disc is used, the switch at the second set pressure is
It can prevent chattering that repeats ON and OFF,
As a result, it is possible to prevent noise, and also to prevent wear of the electrical switching section, thereby increasing durability.

It corresponds to the two set pressures by changing the effective pressure receiving area, primarily with the piston and secondarily with the reversing disk.
Since only one pressure setting spring is required, the number of parts can be reduced and the weight can be reduced.

The electric switching section has an advantage in that it can be manufactured in a small size because the first electrical switching section on the low voltage side and the second electrical switching section on the high voltage side are integrated.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention.
Figures 2 and 3 are sectional views showing the operating state, and Figure 4 is a sectional view showing the operating state.
The figure is a perspective view of the first movable contact, Figure 5 is a perspective view showing the relationship between the fixed contact and the second movable contact, Figure 6 is an explanatory diagram showing the relationship between each setting pressure, and Figures 7 and 8 are 7 is a cross-sectional view of the entire structure, and FIG. 8 is an explanatory diagram showing the relationship between set pressures. 20 is an upper body, 23 is a lower body, 24 is a diaphragm, 33 and 34 are fixed contacts, 35 is a piston,
36, 36, 37 are first movable contacts, 39 is a reversing disk, 41 is a rod, 43, 47 is a spring, 4
8 is the second movable contact.

Claims (1)

[Scope of utility model registration request] A diaphragm is airtightly sandwiched between an upper body and a lower body, a pressure chamber is provided in the upper body, and the switch has a piston on the side opposite to the pressure chamber of the diaphragm that moves up and down by external pressure received through the diaphragm. A reversing disk having a second effective pressure receiving area smaller than the effective pressure receiving area of the piston and protruding upward is housed in an annular locking portion provided on the upper surface of the piston so as to be capable of being reversed vertically. , the piston is accommodated in a holder so as to be movable up and down by a first spring, and a pair of fixed contacts connected to a fixed terminal that locks the holder and protrudes to the outside of the lower body are attached to the lower body. a pair of first movable contacts that are fixed and provided on the lower surface of the piston and the fixed contact form a first electrical switching section, and a second movable contact that is housed in the holder by being resiliently applied from below by a second spring; and the first movable contact form a second electric opening/closing part, and the second movable contact is directly pushed downward by the downward reversal of the reversal disk, and a second electric switch is formed in the through hole provided in the center of the piston. A two-action pressure switch consisting of a rod that passes through it to turn off the electrical switch.