JP2586426B2 - Automatic expansion valve for refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an automatic expansion valve for a refrigeration system constituting a refrigeration cycle of a cooling system for an automobile.

2. Description of the Related Art A refrigeration cycle of an automotive cooling system includes a compressor, a condenser, a liquid receiver, an automatic expansion valve for a refrigeration system, and an evaporator.

As disclosed in Japanese Utility Model Laid-Open No. 53-97754 and the abstract of U.S. Pat. No. 3,450,345, an automatic expansion valve for a refrigeration system rapidly expands a high-temperature and high-pressure liquid refrigerant that has passed through a liquid receiver to form a low-temperature The refrigerant is supplied to the evaporator inlet, and the supply amount of the mist refrigerant is automatically adjusted in accordance with the vaporization state of the refrigerant at the evaporator outlet side.

An example of a conventional automatic expansion valve for a refrigerator will be described with reference to FIG.

The low-pressure refrigerant flows into the low-pressure refrigerant passage 11 formed in the housing 1 from the evaporator outlet side. The diaphragm 21 is vertically displaced according to the temperature of the low-pressure refrigerant. The liquid refrigerant passage 12 communicates with a receiver outlet (not shown), and the mist refrigerant passage 13
Is connected to an evaporator inlet (not shown). The liquid refrigerant passage 12 and the mist refrigerant passage 13 communicate with each other through a communication hole 14.

The substantially cylindrical temperature sensing rod 3 is movably fitted into fitting holes 16a and 16b formed in the housing 1, and an exposed portion 31 as a part thereof is exposed in the low-pressure refrigerant passage 11. This exposed part
The surface of 31 is formed smoothly. Temperature sensing rod 3 is exposed
At 31, the temperature of the refrigerant flowing through the low-pressure refrigerant passage 11 is transmitted to the gas 26 sealed in the diaphragm chamber 25 via the stopper 22 and the diaphragm 21. The flow of the refrigerant near the exposed portion 31 has a laminar flow because the surface of the exposed portion 31 is smooth.

The valve operating rod 7 is movably fitted in a fitting hole 17 formed in the housing 1. The displacement of the diaphragm 21 is controlled by the spherical valve member 6 via the stopper 22, the temperature sensing rod 3, and the valve operating rod 7.
The amount of refrigerant flowing toward the evaporator inlet through the communication hole 14 and the mist-like refrigerant passage 13 is automatically increased or decreased to adjust the capacity of the evaporator.

[Problems to be Solved by the Invention] Since the automatic expansion valve for the refrigeration system is generally arranged on the upstream side of the evaporator, it is easily affected by the warm air which is the vehicle interior air before cooling. Also, when the ambient temperature around the automatic expansion valve for the refrigeration system is high, the ambient temperature is lower than the original heat transfer path from the refrigerant in the low-pressure refrigerant passage to the gas through the temperature sensing rod, stopper, and diaphragm. The heat transfer path leading to the gas through the storage of the diaphragm works more effectively, causing the gas to be heated and causing an erroneous operation such that more nebulized refrigerant is supplied to the evaporator inlet side than necessary. .

Accordingly, it is an object of the present invention to provide an automatic expansion valve for a refrigeration apparatus that improves heat transfer between a refrigerant and a temperature sensing rod in a low-pressure refrigerant passage and has less malfunction.

Means for Solving the Problems To solve the above problems, the present invention is to fix a diaphragm to a housing in which a low-pressure refrigerant passage, a liquid refrigerant passage, and a mist-like refrigerant passage are formed, and the displacement of the diaphragm is controlled by the displacement The valve opening is adjusted via a temperature sensing rod fitted to the housing, and a concave portion or a hole is provided in an exposed portion of the temperature sensing rod exposed in the low-pressure refrigerant passage, so that a heat transfer area is provided. And the concave portion or the hole portion is formed so that the flow of the refrigerant becomes turbulent.

[Operation] According to the above configuration, a concave portion or a hole portion is provided in an exposed portion of the temperature sensing rod, a heat transfer area with the refrigerant flowing in the low-pressure refrigerant passage is increased, and the low-pressure refrigerant is formed by the concave portion or the hole portion. The refrigerant flowing in the passage is disturbed to form a turbulent flow, and the thermal conductivity in the vicinity of the exposed portion is a large value compared to the case where the flow is laminar, so that the heat transfer from the refrigerant to the temperature sensing rod is efficiently performed. It is performed and transmitted to the gas in the diaphragm chamber.

Embodiment An embodiment of an automatic expansion valve for a refrigerating apparatus according to the present invention will be described with reference to FIG.

The housing 1 is provided with a low-pressure refrigerant passage 11, a liquid refrigerant passage 12, a mist-like refrigerant passage 13, a communication hole 14, and a pressure equalizing chamber 15. The left side of the low-pressure refrigerant passage 11 communicates with the evaporator outlet side (not shown), and the right side communicates with the compressor inlet side (not shown). The liquid refrigerant passage 12 communicates with a receiver outlet (not shown). The mist refrigerant passage 13 communicates with an evaporator inlet (not shown). A communication hole that connects the liquid refrigerant passage 12 and the mist-like refrigerant passage 13
The communication hole 14 is formed in the shape of an inverted dish on the liquid refrigerant passage 12 side, and the spherical valve member 6 moves in the vertical direction.
, The amount of refrigerant that is Freon R-12 changes. The equalizing chamber 15 is provided with a low-pressure refrigerant passage by an equalizing pipe (not shown).
The evaporator communicates with the middle of a pipe from 11 to the compressor inlet, and obtains a static pressure in the middle of the pipe as an evaporation pressure of the evaporator. The pressure equalizing chamber 15 is screwed with the diaphragm assembly 2 at the upper part, and is sealed by an O-ring 9c.

The diaphragm assembly 2 is composed of a diaphragm 21, a stopper 22, a seat 24, and a lid 23 made of a thin stainless steel plate. The diaphragm chamber 25 sealed by the diaphragm 21 and the lid 23 has a Freon R-
The gas 26 which is 12 is sealed. The stopper 22 is made of brass or the like, is formed in a disk shape, and is
24 and movably held in the vertical direction. The outer periphery of the stopper 22 has a flange shape, and when the amount of downward displacement of the diaphragm reaches a certain value, the lower surface of the flange abuts against the seat 24 so that the diaphragm 21 is not further displaced downward. I have. A hole 22 a is provided on the lower surface of the stopper 22, and the temperature sensing rod 3 is pushed up by the spring 4 via the receiving member 5, the valve member 6, and the valve operating rod 7 and is in contact therewith.

The temperature sensing rod 3 is made of brass or the like, and is movably fitted into fitting holes 16a and 16b provided in the housing 1. The lower end of the temperature sensing rod 3 abuts on the valve actuating rod 7, and an exposed part 31 as a part thereof is formed. It is exposed in the low-pressure refrigerant passage 11. O-rings 9a and 9b inserted into annular grooves 32a and 32b provided on the outer periphery of the temperature sensing rod 3 are provided between the low-pressure refrigerant passage 11 and the equalizing chamber 15, and between the low-pressure refrigerant passage 11 and the atomized refrigerant passage. This prevents the refrigerant from moving directly to and from 13. The temperature sensing rod 3 is provided with one center hole 33 and twelve side holes 34 communicating therewith. The center hole 33 is closed at the end on the stopper 22 side by a closing member 35 made of brass or the like. As shown in FIG. 2 which is an AA cross section of the temperature sensing rod 3 in FIG. 1, four side holes are formed by providing one through hole 34a and another through hole 34b orthogonal to the through hole 34a. 34 is obtained. The above processing is performed three times in the longitudinal direction at the exposed portion 31, and twelve side holes 34 are provided.

The valve operating rod 7 is made of stainless steel or the like, and is movably fitted in a fitting hole 17 and a communication hole 14 provided in the housing 1. The valve operating rod 7 is reduced in diameter below a fitting portion with the fitting hole 17 so that the refrigerant can pass through a gap with the communication hole 14. The lower end of the valve actuating rod 7 is in contact with the valve member 6 pushed up via the receiving metal 5 by the spring 4 held by the adjusting screw 5 screwed into the housing 1.

The O-ring 9d inserted in the annular groove 51 provided on the outer periphery of the adjusting screw 5 prevents the refrigerant from leaking from the liquid refrigerant passage 12 to the outside. A hexagonal hole 52 is provided at the lower end of the adjusting screw 5, and the spring pressure of the spring 4 can be adjusted by changing the positional relationship between the adjusting screw 5 and the housing 1.

[Operation] The operation of the above embodiment will be described below.

The diaphragm 21 is vertically displaced by a change in the pressure difference between the gas 26 in the diaphragm chamber 25 and the refrigerant in the pressure equalizing chamber 15. The pressure of the gas 26 is determined by the temperature of the refrigerant flowing through the low-pressure refrigerant passage 11, which is transmitted from the exposed portion 31 of the temperature sensing rod 3 via the stopper 22 and the diaphragm 21. The pressure of the refrigerant in the pressure equalizing chamber 15 is the evaporation pressure of an evaporator (not shown).

When the temperature in the cabin rises, the refrigerant evaporates rapidly in the evaporator, and the temperature of the refrigerant flowing into the low-pressure refrigerant passage 11 rises, the heat is transferred through the temperature sensing rod 3, the stopper 22, and the diaphragm 21. The gas 26 expands, and the diaphragm 21 is displaced downward. This displacement is the stopper 22, the temperature sensing rod 3, the valve operating rod 7
Is transmitted to the valve member 6, the valve member 6 is pushed down, and the amount of refrigerant flowing toward the evaporator inlet side through the communication hole 14 and the mist-like refrigerant passage 13 increases. Further, if the temperature in the passenger compartment decreases and the temperature of the refrigerant flowing into the low-pressure refrigerant passage 11 decreases, the amount of the refrigerant flowing toward the evaporator inlet side decreases by the reverse operation. Thus, the capacity of the evaporator is adjusted by automatically increasing or decreasing the amount of the refrigerant supplied to the evaporator.

In the above operation, the exposed portion 31 is provided with the side hole 34, and the heat transfer area is enlarged. Further, the flow of the refrigerant is disturbed by the side holes 34 to form a turbulent flow, and the heat conductivity of the refrigerant is improved as compared with the case where the flow forms a laminar flow. Further, the refrigerant in the center hole 33 reaches the lower end of the closing member 35 and approaches the stopper 22.

As described above, according to the present embodiment, the heat transfer area in the exposed portion 31 is increased, the thermal conductivity is increased by the turbulent flow of the refrigerant, and the conduction distance is further reduced by the center hole 33. Heat transfer from the refrigerant in the low-pressure refrigerant passage 11 to the gas 26 in the diaphragm chamber 25 is performed very efficiently.

"Other Embodiments" The present invention is not limited to the details of the above-described embodiment. For example, as shown in FIG.
The spiral groove 36 may be engraved. Further, as shown in FIG. 4, a plurality of annular grooves 37 may be provided in the exposed portion 31 of the temperature sensing rod 3 to form the fins 38. According to these embodiments, since the temperature sensing rod 3 can be manufactured only by turning, it can be provided at low cost.

"Effects of the Invention" As described above, the automatic expansion valve for the refrigeration system of the present invention increases the heat transfer area by providing a concave portion or a hole portion in the exposed portion of the temperature sensing rod exposed in the low-pressure refrigerant passage, Further, since the flow of the refrigerant is turbulent due to the concave portion or the hole portion, heat transfer between the refrigerant and the temperature sensing rod is efficiently performed and is transmitted to the gas in the diaphragm chamber. On the side, the effect of warm air, which is the cabin air before cooling,
There is an effect that malfunction due to the influence of the ambient atmosphere temperature can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an automatic expansion valve for a refrigerating apparatus according to the present invention, FIG. 2 is a sectional view showing a main part of FIG. 1, and FIG. 3 is an automatic expansion valve for a refrigerating apparatus according to the present invention. FIG. 4 is a cross-sectional view showing still another embodiment of the automatic expansion valve for a refrigeration system according to the present invention, and FIG. 5 is a cross-sectional view showing a conventional automatic expansion valve for a refrigeration system. It is. 1 ... housing, 3 ... temperature sensing rod, 6 ... valve member, 7 ...
... Valve operating rod, 11 ... Low-pressure refrigerant passage, 12 ... Liquid refrigerant passage,
13 mist refrigerant passage, 21 diaphragm, 31 exposed part, 34 hole (side hole), 36, 37 recess (groove).

Claims (1)

(57) [Claims] 1. A diaphragm is fixed to a housing in which a low-pressure refrigerant passage, a liquid refrigerant passage, and a mist-like refrigerant passage are formed, and the displacement of the diaphragm is controlled by a valve opening via a temperature sensing rod fitted to the housing. Is provided, a concave portion or a hole portion is provided in an exposed portion exposed in the low-pressure refrigerant passage of the temperature sensing rod to increase a heat transfer area, and the flow of the refrigerant flows through the concave portion or the hole portion. An automatic expansion valve for a refrigeration system, which is formed to have turbulent flow.