JPS648416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a pressure switch, and for example, to a switch that responds to the pressure of a fluid such as a refrigerant in a refrigerant circuit of an automobile air conditioner.

(Prior Art) In general, the refrigerant circuit of an automobile air conditioner, as shown in FIG. Low pressure switch 2 of 2
Different types of pressure switches are used. If the refrigerant pressure abnormally increases or decreases, it is detected by the high pressure switch 1 or low pressure switch 2, respectively, and an electromagnetic switch installed between the compressor 3 and the engine 4 that drives this compressor 3 is detected. The clutch 5 is released to stop the compressor 3. especially,
If the refrigerant pressure decreases due to a refrigerant leak,
The lubricating oil will also leak along with the refrigerant gas.
If the compressor 3 continues to be driven as it is, it will seize up and become locked, putting a heavy load on the engine 4 connected via the electromagnetic clutch 5, making it impossible to run. If this situation occurs while driving at high speed, , causing an accident.

Conventionally, a structure has been adopted in which a high pressure switch 1 and a low pressure switch 2, which detect abnormal rise and fall of fluid, respectively, are attached via attachments 7 to a receiver tank 6 provided in a refrigerant circuit.

In the conventional device shown in FIG. 1, a high-pressure switch and a low-pressure switch must be installed, which requires a large installation space and cannot be connected without an attachment. There are problems that hinder pricing.

Therefore, as described in JP-A-58-19829, a pressure switch has been proposed in which a single switch is turned on only between different set pressures and turned off at other pressures.

(Problems to be Solved by the Invention) Furthermore, in the pressure switch described in the above-mentioned Japanese Patent Application Laid-open No. 19829-1982, it is possible for one switch to turn on only between different set pressures and turn off at other pressures. However, there was a problem in that the set pressure could not be finely adjusted.

The present invention was created in view of the above problems, and has the function of a high pressure switch that operates above the set pressure on the high pressure side, and the function of a low pressure switch that operates below the set pressure on the low pressure side, and furthermore, it has the function of a low pressure switch that operates below the set pressure on the low pressure side. The purpose of this invention is to provide a pressure switch that can adjust the pressure, making it possible to reduce the size and cost of the entire equipment to which it is applied.

[Structure of the invention]

(Means for Solving the Problems) The pressure switch of the present invention has a pressure receiving member that is displaced in response to the pressure of a fluid, an actuating contact that is linked to the displacement of the pressure receiving member, and a pressure of the fluid applied to the actuating contact. a first coil spring that provides a repulsive force in a direction opposite to the repulsive force of the first coil spring; and a pair of intermediate contacts each disposed at a position where they come into contact with the operating contact due to displacement of the operating contact against the repulsive force of the first coil spring. a second coil spring that applies a stronger repulsive force to the pair of intermediate contacts in the same direction as the first coil spring and supports the pair of intermediate contacts so that they can be displaced against the pressure applied to the operating contact; A pair of stationary contacts that are in constant contact with the pair of intermediate contacts and that are released from contact with the pair of intermediate contacts by displacement of the pair of intermediate contacts against the repulsive force of the second spring. death,
One end of the second coil spring engages with the intermediate contact via a contact holder, and the other end engages with a second adjusting screw screwed together so as to be able to move forward and backward, and one end of the first coil spring The actuating contact was engaged through a bush that was fitted in the contact holder so that it could move forward and backward, and the other end was engaged with a first adjustment screw that was screwed into the center of the second adjustment screw so that it could move back and forth. It is characterized by this.

(Function) In the pressure switch of the present invention, when the fluid pressure is within the set pressure range, the fluid pressure is applied to the pressure receiving member, displacing the operating contact against the first spring, and the operating contact displaces the intermediate contact. , and the pressure switch is held on. In this state, when the fluid pressure increases abnormally, the working contact is displaced against the first spring and the second spring, and the working contact displaces the pair of intermediate contacts to separate them from the pair of stationary contacts, The pressure switch is turned off.
When the fluid pressure further decreases abnormally, the working contact is displaced by the repulsive force of the first spring, and the working contact is separated from the pair of intermediate contacts,
The switch is turned off. The set pressure is adjusted by adjusting the repulsive forces of the first and second springs using the first and second screws.

(Embodiment) The configuration of an embodiment of the present invention will be explained with reference to FIGS. 2 and 3.

As shown in FIG. 2, in an automobile air conditioner, the refrigeration cycle includes a compressor 16 connected to an engine 18 via an electromagnetic clutch 17;
It consists of a condenser 19 connected to the discharge side of the compressor 16, a receiver tank 20, and an evaporator 21, and the evaporator 21 is connected to the suction side of the compressor 16. A pressure switch 22 is located near the receiver tank 20 and connected to the refrigeration cycle.

The construction of the pressure switch 22 will be explained with reference to FIG.

One end opening of the cylindrical case 25 is hermetically closed by a pressure receiving member, for example, a diaphragm 26 . A socket 27, which is connected to the refrigeration cycle via a rubber packing 28, is attached to the periphery of the diaphragm 26 at one end of the open surface of the case 25, and is integrally connected to the case 25 by caulking means or the like. A pressurizing chamber 29 facing the pressure receiving surface of the diaphragm 26 is formed inside the socket 27, and this pressurizing chamber 29 is connected to the passage 3.
0 to the refrigerant cycle such that refrigerant fluid pressure is applied to the diaphragm 26.

Reference numeral 32 denotes an operating contact which connects the pressurizing chamber 2 of the diaphragm 26 via the diaphragm holder 33.
It is connected to the opposite surface of the 9 side.

Reference numeral 35 designates a first coil spring for low pressure operation, one end of which is engaged with the operating contact 32 via a bush 36, and the other end of which is engaged with the tip of the first adjusting screw 38 via a spring holder 37. has been done. The first coil spring 36 is adapted to apply a repulsive force to the operating contact 32 in a direction opposite to the pressure of the refrigerant.

Further, reference numerals 40 and 40 denote a pair of intermediate contacts, which are disposed within the case 25 and connected to the operating contact 32.
The actuating contact 32 is disposed at a position where the actuating contact 32 is brought into contact with the actuating contact 32 by being displaced by an increase in refrigerant pressure.

Reference numeral 41 denotes a second coil spring for high-pressure operation, one end of which is engaged with the pair of intermediate contacts 40, 40 through an annular contact holder 42, and the bush 36 can move forward and backward into this contact holder 42. It is inserted.
The other end of the second coil spring 41 is engaged with the tip of a second screw 44 via a coil spring holder 43. The pair of intermediate contacts 40, 40 are each supported so as to be able to be displaced against the pressure of the refrigerant applied via the operating contact 32. The second coil spring 41 is a spring for high-pressure operation, and has a sufficiently stronger repulsive force than the first coil spring 35.

Further, the second adjustment screw 44 is screwed to the other end surface of the case 25 so as to be freely retractable in the axial direction, and the first adjustment screw 38 is formed at the axial center of the second adjustment screw 44. Both screws 3 are screwed into the female screw part.
By rotating the springs 8 and 44, the repulsive force of the corresponding first coil spring 35 and second coil spring 41 can be adjusted as appropriate.

Reference numerals 46 and 46 denote a pair of fixed contacts, and the pair of fixed contacts 46 and 46 are always connected to the pair of intermediate contacts 40 and 40 by the repulsive force of the second coil spring 41, respectively. Then, by displacement of the pair of intermediate contacts 40, 40 in the direction of increasing fluid pressure, the pair of intermediate contacts 40, 40 and both fixed contacts 46, 46 are released from contact, respectively. Further, these fixed contacts 46, 46 are connected to a terminal portion 46 led out to the outside of the case 25.
a is integrally formed.

For example, the first coil spring 3
The operating pressure on the low pressure side required to compress 5 is 2Kg/cm ² G
The operating pressure on the high pressure side required to compress the first coil spring 35 and the second coil spring 41 is 25 Kg/cm ² G, and the refrigerant pressure in the refrigeration cycle shown in FIG. 2 is usually 10 to 15 Kg. /
The pressure is set at approximately cm ² G.

Next, the operation of this embodiment will be explained.

Refrigerant pressure within a predetermined set pressure range is applied to the diaphragm 26, displacing the working contact 32 interlocking with the diaphragm 26 against the first coil spring 35, and the working contact 32 is connected to the pair of intermediate contacts 40, 40. The refrigerant pressure is also applied to the second coil spring 41 through the intermediate contacts 40, 40, but since the repulsive force of the second coil spring 41 is sufficiently large compared to the first coil spring, Second
The coil spring 41 is not compressed, and the pair of intermediate contacts 40, 40 are held in contact with the pair of stationary contacts 46, 46, respectively. In this state, a pair of fixed contacts 4
The terminal portions 46a, 46a of the compressors 6 and 46 are electrically connected, the pressure switch is turned on, the electromagnetic clutch 17 is connected, and the driving force of the engine 18 is maintained in the compressor 16 in a conductive state.

Next, due to leakage of refrigerant gas in the refrigerant cycle, etc.
When the pressure of the refrigerant abnormally decreases to, for example, 2 Kg/cm ² G or less, the repulsive force of the first coil spring 35 is large compared to the refrigerant pressure, and the actuation contact 32 is displaced toward the pressure receiving chamber 29 side of the diaphragm 26, causing the actuation to occur. The contact 32 is a pair of intermediate contacts 40,
40, the pressure switch in the state shown in FIG. This prevents the lock state from becoming burnt out due to leakage.

Further, when the refrigerant pressure abnormally increases to, for example, 25 kg/cm ² G or more, the pressure applied to the diaphragm 26 is applied to the pair of intermediate contacts 40, 40 via the operating contact 32, and the second coil spring 4
1 is compressed, and a pair of intermediate contacts 40, 40
is separated from the pair of fixed contacts 46, 46,
The pressure switch is turned off and compressor 1
6 is stopped.

Note that the operating pressure on the low pressure side is the first screw 38.
is rotated and adjusted by adjusting the repulsive force of the first coil spring 35 to set the off-operation pressure on the low pressure side.

In addition, the operating pressure on the high pressure side can be adjusted using a screwdriver etc.
While fixing the screw 38, the second adjusting screw 44 is rotated to adjust the repulsive force of the second coil spring 41, thereby setting the off-operation pressure on the high pressure side.

In this way, the operating pressure on the low-pressure side and the operating pressure on the high-pressure side can be set separately, and can be set to appropriate pressures.

In the above-mentioned embodiments, a case has been described in which the air conditioner is responsive to refrigerant pressure in an automobile air conditioner, but it is also possible to respond to various fluid pressures.

〔Effect of the invention〕

According to the present invention, one pressure switch can have two functions, one for high pressure operation and one for low pressure operation, and the installation space for the pressure switch can be reduced by the installation space for a conventional pressure switch for high pressure and a pressure switch for low pressure. In addition, it does not require any special attachments for installation, is compact overall, and can set the off operating pressure on the low pressure side by adjusting the first adjustment screw, and the second adjustment screw. The off-operating pressure on the high pressure side can be set by adjusting the screw, and one end of the first adjusting screw is inserted into a contact holder that engages the second adjusting coil spring, and the other end is inserted into the contact holder that engages the second adjusting coil spring. Since both coil springs are screwed into the engaged second adjusting screw, the two coil springs have the effect of ensuring reliable operation without interfering with each other.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a refrigeration cycle using a conventional pressure switch, Fig. 2 is a system diagram of a refrigeration cycle showing an example of using the pressure switch of the present invention, and Fig. 3 is a system diagram of an embodiment of the present invention. FIG. 3 is a longitudinal side view of the pressure switch. 26...Diaphragm of pressure receiving member, 32...Operating contact, 35...First coil spring, 36...Button, 38...First adjustment spring, 40...Intermediate contact, 41...Second
coil spring, 42...contact holder, 44...second adjustment spring, 46...fixed contact.

Claims (1)

[Claims] 1. A pressure-receiving member that is displaced in response to fluid pressure, and an operating contact that is linked to the displacement of this pressure-receiving member.
A first coil spring that applies a repulsive force to the working contact in a direction opposite to the pressure of the fluid, and a position where the working contact is brought into contact with the working contact due to displacement of the working contact against the repulsive force of the first coil spring. A pair of intermediate contacts are arranged respectively, and a stronger repulsive force is applied to the pair of intermediate contacts in the same direction as the first coil spring, so that the pair of intermediate contacts can be displaced in response to the pressure applied to the operating contact. A supporting second coil spring is in constant contact with the pair of intermediate contacts, and the contact with the pair of intermediate contacts is released by displacement of the pair of intermediate contacts against the repulsive force of the second spring. a pair of fixed contacts, one end of the second coil spring engages with the intermediate contact via a contact holder, and the other end engages with a second adjusting screw screwed together so as to be freely retractable. One end of the first coil spring engages with the operating contact via a bush that is fitted into the contact holder so that it can move forward and backward, and the other end is screwed into the center of the second adjustment screw so that it can move back and forth. 1. A pressure switch, characterized in that the pressure switch engages a first adjustment screw that is connected to the pressure switch.