JP2002131158A - Pressure switch with temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure switch 100 with a temperature sensor whose internal structure is simple, with high assembling characteristics and reliability, at a low cost. SOLUTION: An inversion plate 5 which inverts according to the pressure of a detected fluid is provided. A rod-like temperature sensor 20 is provided so as to penetrate the central part of under-pressure operation mechanisms 5, 6, 7, and 8 up to the inversion plate 5. On end of the temperature sensor 20 is made to press the inversion plate 5 by an elastic member 19 whose one end is fixed to a housing 2 side, so that the inversion plate 5 is interlocked with the temperature sensor 20. Thus, one end of the rod-like temperature sensor 20 is made to contact the inversion plate 5, for raised detection precision and detection response for the temperature of the fluid which is to be detected. Since the temperature sensor 20 penetrates the central part of the under-pressure operation mechanisms 5, 6, 7, and 8 so that the temperature sensor 20 is pressurized with the elastic member 19, such operations as connecting/fixing and assembling of the temperature sensor 20 are simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch with a temperature sensor suitable for detecting a change in pressure of high-pressure refrigerant in a refrigeration cycle of a vehicle air conditioner or the like.

[0002]

2. Description of the Related Art A pressure switch is mounted on a high-pressure side of a refrigeration cycle such as an air conditioner for a vehicle, and detects an abnormal rise or fall in the pressure of high-pressure refrigerant in the refrigeration cycle. O clutch
N, used to turn off.

[0003] Further, it is also used for controlling a cooling fan of a condenser by detecting a set intermediate pressure.

Therefore, in general, a pressure switch is provided with a pressure receiving mechanism that operates in accordance with the pressure of a detection fluid applied to the surface of a diaphragm, and an opening / closing lever that opens and closes an electrical contact in accordance with the operation of the pressure receiving mechanism. Have been.

[0005] However, since the conventional pressure switch operates only at a preset pressure, it is necessary to prepare various types of switches according to the set pressure. In addition, it was impossible to change the set value depending on the operation state.

On the other hand, if a pressure sensor is used, it is possible to change the set value according to the operating state.
Since the cost increases, Japanese Patent Application Laid-Open No. 11-167851
As shown in the publication, a pressure switch with a temperature sensor has been proposed in which a temperature sensor is provided in a diaphragm portion of a pressure switch and a pressure corresponding to the temperature can be obtained from the temperature of a detected fluid.

[0007]

However, when a temperature sensor is arranged on the detection fluid side from the diaphragm, the wiring is bypassed to movable parts such as a pressure receiving operation mechanism and an opening / closing lever, and is wired to a terminal on the opposite side of the temperature sensor. Needs come out.

For this reason, a complicated wiring path must be formed in the housing of the pressure switch, and the assemblability and reliability are reduced. In addition, there is a problem that the number of changes to the structure of the conventional pressure switch increases and the cost increases.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a low-cost pressure switch with a temperature sensor having a simple internal structure, high assemblability and reliability. I do.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, the temperature sensor (20) has a rod shape, and the pressure receiving operation mechanism (5, 6, 7, 8) has a function of detecting a fluid to be detected. A reversing plate (5) that performs a reversing operation according to the pressure, and a temperature sensor (20) is arranged so that the center of the pressure receiving mechanism (5, 6, 7, 8) penetrates to the reversing plate (5); One end of the temperature sensor (20) is pressed against the reversing plate (5) by an elastic member (19) fixed to the housing (2) so that the reversing plate (5) and the temperature sensor (20) are interlocked. It is characterized by.

With this arrangement, one end of the rod-shaped temperature sensor is brought into contact with the reversing plate of the pressure receiving operation mechanism, so that the accuracy of detecting the temperature of the detection fluid and the detection response can be improved. In addition, since the temperature sensor penetrates the center of the pressure receiving operation mechanism and the temperature sensor is pressed by the elastic member, the operation of connecting and fixing the temperature sensor and the operation of assembling can be simplified.

According to the second aspect of the present invention, the elastic member (1
8, 19) are made of conductive material and have terminals (1).
6, 17), and the temperature sensor (20)
A conductor (21b, 21b,
27), the elastic members (18, 19) and the conductor (21).
b, 27) is always ensured.

Thus, the output of the temperature sensor can be taken out of the terminal regardless of the operation state of the pressure receiving mechanism.

According to the third aspect of the present invention, the temperature sensor (2
0) is characterized in that the temperature detecting element (22) is arranged inside one end of the cylindrical case (21).

Thus, the accuracy of detecting the temperature of the detection fluid at one end of the temperature sensor and the detection response can be improved.

According to the present invention, the conductor portion (21)
a, 27) is a first sensor provided at the other end of the temperature sensor (20).
A temperature detecting element (22) having a conductor (27) and a second conductor (21a) provided on a side surface of the temperature sensor (20);
Of the first and second conductors are respectively the first and second conductor portions (2
1a, 27).

Thus, the output of the temperature detecting element can be always taken out by keeping the contact with the conductor.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing the structure of a pressure switch 100 with a temperature sensor according to an embodiment of the present invention.

Pressure switch 100 with temperature sensor of the present invention
Is mounted in a high-pressure refrigerant pipe between a receiver and an expansion valve in a refrigeration cycle of a vehicle air conditioner or the like, and is constituted by a body 1 and a case 2 as a housing forming an outer shape.

The body 1 is made of galvanized mild steel or an aluminum alloy. One of the bodies 1 is provided with a connection portion provided with a pressure inlet 1a communicating with the refrigerant passage of the refrigeration cycle. And combined with caulking. Case 2 is made of an insulating material such as glass fiber reinforced polybutylene terephthalate resin (PBT).

When combining the body 1 and the case 2,
The periphery of the diaphragm 4 is hermetically fixed using a packing 3 made of a rubber-like substance. The diaphragm 4 serves to prevent the refrigerant from entering the case 2 and to transmit the refrigerant pressure to various pressure transmitting members in the case 2, and uses a thin film of a polyimide resin as a material thereof. Inside the case 2 sealed by the diaphragm 4, the following functional components are housed.

The high-pressure holder 6 is slidably disposed in the case 2 in the axial direction. In the outer peripheral wall portion 6a of the high-pressure holder 6, a circular dish-shaped high-pressure reversing plate 5 in which three reversing plates are stacked is housed.

When a pressure exceeding a predetermined value is applied from the direction of the protruding portion to the high-pressure reversing plate 5, the protruding portion reverses in the opposite direction, and when the pressure falls below the predetermined value. This is a so-called snap disk having a hysteresis characteristic of reversing its initial shape again.

When this high-pressure reversing plate 5 is composed of a plurality of sheets,
There is an advantage that the durability is improved and the variation of the operation value can be reduced. A disadvantage of using multiple plates is that friction occurs at the mutually contacting surfaces of the reversing plate. In order to reduce this friction, a lubricant containing a small amount of molybdenum dioxide solid powder may be applied to the interface, which makes the operation extremely stable.

A central projection 6b is formed at the center of the high-pressure holder 6 on the side opposite to the high-pressure reversing plate 5, and a hole formed at the center of the circular dish-shaped low-pressure reversing plate 8 is formed on the outer peripheral surface thereof. It is slidably fitted. An annular projection 6c is formed on the outer periphery of the central projection 6b to press the low-pressure reversing plate 8.

The low-pressure reversing plate 8 senses the low-pressure cut-off pressure and reverses the shape by a snap action. The low-pressure reversing plate 8 is formed on a step 2 a formed inside the case 2.
Are housed so as to be engaged with the outer peripheral portion.

At the center of the high-pressure reversing plate 5, high-pressure holder 6, and low-pressure reversing plate 8, a cylindrical temperature sensor 20 is disposed so as to pass therethrough. The structure of the temperature sensor 20 is one of the main parts of the present invention, and will be described later.

Between the outer surface of the temperature sensor 20 and the inner surface of the central hole of the high-pressure holder 6, a cylindrical high-pressure operating rod 7 is incorporated so as to be slidable in the axial direction. This high pressure operating rod 7
Is in contact with the anti-diaphragm side of the high-pressure reversing plate 5,
The reverse displacement of the high-voltage reversing plate 5 is transmitted to the next electrical contact switching unit.

On the inner side of the low-pressure reversing plate 8, open / close levers 12, 1 having one end fixed to terminals 10, 11 are fixed.
Electric contacts 14 and 15 forming an open / close switch are caulked and fixed at the respective ends.

An intermediate portion between the opening / closing levers 12 and 13 has a wide shape provided with a through-hole, and a temperature sensor 20 penetrates slidably in the axial direction. Opening and closing lever 1
3.

Next, the temperature sensor 20 which is an essential part of the present invention will be described.
2 and the holding structure inside the pressure switch 100 will be described with reference to FIGS. FIG. 2 is a cross-sectional view illustrating the structure of the temperature sensor 20 according to the embodiment of the present invention, and FIG. 3 is a partial structural view illustrating a contact state between the temperature sensor 20 and the terminal 16.

Reference numeral 21 denotes a metal cup having a deep hole as a cylindrical case, and a thermistor 22 as a temperature sensor element is press-fitted into the bottom of the deep hole. One end of the output of the thermistor 22 is electrically connected to the metal cup 21, and is brought into contact with a lever 18, which will be described later, at the opening portion side of the metal cup 21 where the second conductor 21 a is thicker.

The other end of the output of the thermistor 22 is connected to a pin 25 from a lead wire 24, and a metal cap 27 into which the pin 25 is press-fitted serves as a first conductor, and contacts a lever 19 which is an elastic member described later. And taken out.

Reference numerals 23 and 26 denote insulators made of resin or the like. Reference numeral 23 denotes a molded part formed by molding or inserting an insulating tube around the outer periphery of the metal cup 21. Reference numeral 26 denotes a molded part. Press-fit and connect lead 24 to pin 2
5 and then press-fit into the opening of the metal cup 21.

Next, regarding the holding structure, the temperature sensor 20
Is arranged to penetrate the center of the internal mechanism as described above, one end is supported by the high-pressure holder 6 via the high-pressure operating rod 7, and the other end penetrates a lever 18 caulked and fixed to the terminal 16, One end of the output of the temperature sensor 20 is connected to the terminal by connecting and supporting the conductor portion 21a of the temperature sensor 20 with the claw portion 18a cut and raised by the lever 18 and contacting and sliding the claw portion 18a and the conductor portion 21a. 1
It is taken out to 6.

In the axial direction, the temperature sensor 2 is a lever 19 which is an elastic member fixed at one end to the terminal 17.
0, the other end of the output of the temperature sensor 20 is taken out to the terminal 17 and the temperature sensor 2
The zero temperature detector 21 b is pressed against the back surface of the reversing plate 5. However, a flange may be formed in the conductor 21a of the temperature sensor 20, and the lever 18 may be made to have the same elastic shape as the lever 19 to push up the flange in the direction of the reversing plate 5 to make contact.

By the way, in order to improve the sensitivity of the temperature sensor 20, two of the three reversing plates 5 are provided with a round hole at the center to penetrate the temperature sensor 20 so that the reversing plate 5 on the diaphragm 4 side is the most reversible. The temperature is detected by contacting the temperature detection unit 21b. However, since the parts are shared with the conventional switch, 3
Both sheets may be without holes.

As a result, the reversing plate 5 and the temperature sensor 20 reciprocate integrally, and the pressure receiving operation mechanism 5 is applied to the reversing plate 5 which is in contact with the detection fluid via the thin-film diaphragm 4. , 6, 7, and 8, the state where the temperature sensor 20 is always in contact can be maintained.

Also, regardless of the reciprocating motion of the temperature sensor 20, the conductors 21a, 27 provided on the temperature sensor 20 are always provided.
And levers 18, 1 connected to terminals 16, 17
9, the output of the temperature sensor 22 can be taken out of the terminals 16, 17 irrespective of the operating conditions of the pressure receiving operation mechanisms 5, 6, 7, 8;
It is possible to constantly detect the temperature of the detection fluid.

The structure of the pressure switch portion is the same as that of the conventional high-low pressure dual operation type, and the arrangement of the temperature sensor 20 is similar to that of the conventional high-medium-low pressure three-operation type operation rod at the center. Structure, easy to assemble, high reliability,
Because the parts can be shared with the conventional switch, a low-cost pressure switch with a temperature sensor can be obtained.

The aforementioned terminals 10, 11, 16, 1
Numeral 7 constitutes a connector part which penetrates through the wall part 2b of the case 2 and outputs a signal from the pressure switch and the temperature sensor 20 to a refrigeration cycle control device (not shown).

Next, a method of assembling the pressure switch with the temperature sensor according to the present embodiment will be described. First case 2
Then, the terminals 17, 16, 11, 10 in which the levers 19, 18, 13, 12 are integrated are sequentially press-fitted. Next, the low-pressure reversing plate 8, the high-pressure holder 6, the high-pressure operating rod 7, the temperature sensor 20, and the high-pressure reversing plate 5 are sequentially inserted and set. And
The body 1 is set with the diaphragm 4 and the packing 3 interposed therebetween, and the outer periphery is rolled and joined to complete the assembly.

Next, the operation of the pressure switch with temperature sensor according to the present embodiment will be described with reference to FIG. 4A and 4B are cross-sectional views showing an operation state of the pressure switch with a temperature sensor according to the present invention, wherein FIG. 4A is a low pressure ON state, and FIG.
Indicates a high pressure OFF state.

FIG. 1 shows a pressure inlet 1a.
Is in a state where atmospheric pressure is applied to the
Open between 4,15. From this state, the pressure inlet 1a
When the pressure applied to the diaphragm 4 rises and reaches a pressure equal to or higher than the low pressure set value, the state shown in FIG.

The high-pressure holder 6 slides downward together with the high-pressure reversing plate 5, the high-pressure operating rod 7, and the temperature sensor 20 to push the low-pressure reversing plate 8 to be reversed, and to depress the opening / closing lever 12 to make the electric power. The switch circuit is turned on by closing the contacts 14 and 15. When the temperature sensor 20 slides downward in the figure, the lever 19 is pressed downward in the figure.
The contact between the 0 conductor portions 21a, 27 and the levers 18, 19 is ensured.

When the refrigerant pressure further rises and reaches a pressure equal to or higher than the high pressure set value, the state shown in FIG. The high-pressure reversing plate 5 is reversed, and the high-pressure operating rod 7 slides downward together with the temperature sensor 20 to push down the opening / closing lever 13 so that the electric contact 1
Open between 4, 15 to turn off the switch circuit. When the temperature sensor 20 slides downward in the figure, the lever 19 is further pressed downward in the figure.
a, 27 and the levers 18, 19 are kept in contact with each other.

Next, when the refrigerant pressure decreases and decreases from the high pressure set value by the amount of hysteresis, the high pressure reversing plate 5 returns to the original state and returns to the state shown in FIG.
N. When the refrigerant pressure further decreases and decreases from the low pressure set value by the amount of the hysteresis, the low pressure reversing plate 8 returns to the original state as shown in FIG. 1 and the switch circuit is turned off.

Next, the operation of the detection processing device 200 using the pressure switch with temperature sensor 100 in the present embodiment will be described with reference to the control block diagram of FIG.

The pressure switch section of the pressure switch with temperature sensor 100 is turned off when the pressure of the high-pressure refrigerant in the refrigeration cycle exceeds the high-pressure set value or falls below the low-pressure set value.
Thus, the compressor is stopped by disconnecting the electromagnetic clutch 300 from the compressor operation control means 201 to prevent failure or damage of the refrigeration cycle equipment due to abnormally high or abnormally low pressure.

When the compressor is started, the temperature sensor 2
When the refrigerant temperature is detected as 0 and the temperature is lower than the first set value, the compressor operation control means 201 performs control for maintaining the state in which the electromagnetic clutch 300 is disengaged. This is to prevent the compressor from being worn out due to poor lubrication at low temperatures, and to prevent the liquefied refrigerant from being compressed and damaged.

In the detection processing device 200, when the refrigerant temperature detected by the temperature sensor 20 reaches a temperature equal to or higher than a second set value corresponding to the intermediate pressure, the condenser cooling control is performed based on the relationship between the refrigerant pressure and the saturated refrigerant temperature. Means 202 is used for control such as switching the electric fan 400 from Lo to Hi.

When the temperature exceeds the high-pressure set value and turns off, the refrigerant temperature detected by the temperature sensor 20 is lower than the saturated refrigerant temperature corresponding to the pressure at which the high-pressure reversing plate 5 is inverted, and the difference between the saturated refrigerant temperature. If the temperature difference is equal to or greater than the third set value, the abnormality determination unit 203 determines that the temperature is abnormal,
Warn from zero.

This abnormality occurs when the refrigerant is overfilled more than an appropriate amount. Conventionally, the refrigerant pressure becomes too high, and the electromagnetic clutch 300 is frequently disengaged due to high pressure cut. Although this has been reduced, this can be prevented beforehand by issuing a warning.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a pressure switch with a temperature sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a structure of a temperature sensor according to an embodiment of the present invention.

3A and 3B are partial structural views showing a contact state between a temperature sensor and a terminal, wherein FIG. 3A is a side view and FIG. 3B is a plan view.

FIG. 4 is a cross-sectional view showing an operation state of the pressure switch with a temperature sensor according to the present invention, wherein FIG.
(B) shows a high pressure OFF state.

FIG. 5 is a control block diagram of a detection processing device using a pressure switch with a temperature sensor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body (housing) 2 Case (housing) 4 Diaphragm 5 High pressure reversing plate (pressure receiving mechanism) 6 High pressure holder (pressure receiving mechanism) 7 High pressure operating rod (pressure receiving mechanism) 8 Low pressure reversing plate (pressure receiving mechanism) 10, 11 Terminals 12, 13 Opening / closing levers 14, 15 Electrical contacts 16, 17 Terminals 18, 19 Lever (elastic member) 20 Temperature sensor 21 Metal cup (cylindrical case) 21a Second conductor portion 22 Thermistor (temperature detecting element) 27 Metal cap ( 1st conductor)

Claims (4)

[Claims] A diaphragm (4) housed in the housing (1, 2) and sealing the inside of the housing (1, 2) with respect to a detection fluid; and a diaphragm housed in the housing (1, 2). A pressure receiving mechanism (5, 6, 7, 8) that operates in accordance with the pressure of the detection fluid applied to the surface of the diaphragm (4); and a pressure receiving mechanism (5) housed in the housing (1, 2). 5, 6, 7, 8) according to the operation of the electrical contacts (1
An opening / closing lever (12, 13) for opening and closing the open / close lever (12, 13); and a temperature sensor (20) housed in the housing (1, 2) for detecting the temperature of the detection fluid. , 13) and the temperature sensor (2)
0) Terminals (10, 11, 1) for connecting the electric wiring
In the pressure switch with a temperature sensor provided in the housing (2), the temperature sensor (20) is rod-shaped, and the pressure receiving operation mechanism (5, 6, 7, 8) is a pressure switch of the detection fluid. And the temperature sensor (20) is disposed so that the central part of the pressure receiving mechanism (5, 6, 7, 8) penetrates to the reversing plate (5) up to the reversing plate (5). Then, one end of the temperature sensor (20) is pressed against the reversing plate (5) by an elastic member (19) fixed to the housing (2), and the reversing plate (5) and the temperature sensor (20) are pressed. And a pressure switch with a temperature sensor. 2. The elastic member (18, 19) is made of a conductive material and connected to the terminal (16, 17), and the temperature sensor (20) has a built-in temperature detecting element (22). And a conductor portion (21a, 27) electrically connected to the temperature detecting element (22) on the surface thereof. The elastic member (18, 19) and the conductor portion (21a, 2
2. The pressure switch with a temperature sensor according to claim 1, wherein a contact state with the temperature sensor is always ensured. 3. The temperature sensor (20) is provided inside one end of the cylindrical case (21).
The pressure switch with a temperature sensor according to claim 2, wherein 2) is arranged. 4. The first conductor (27) provided at the other end of the temperature sensor (20), wherein the conductor (21a, 27) is provided.
And a second conductor portion (21a) provided on a side surface of the temperature sensor (20), wherein first and second electric wires of the temperature detection element (22) are respectively the first and second conductor portions. (2
The pressure switch with a temperature sensor according to claim 2 or 3, wherein the pressure switch is connected to 1a, 27).