JP3920059B2 - Expansion valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion valve, and in particular, a high-temperature / high-pressure liquid refrigerant is adiabatically expanded into a low-temperature / low-pressure gas-liquid mixed refrigerant in a refrigeration cycle of an automotive air conditioner system, and the state of the refrigerant at an evaporator outlet is predetermined. The present invention relates to an expansion valve that controls the flow rate of refrigerant so that the degree of superheat is reached.
[0002]
[Prior art]
In automotive air conditioner systems, high-temperature and high-pressure gas refrigerant compressed by a compressor is condensed by a condenser, and the condensed liquid refrigerant is adiabatically expanded by an expansion valve to form a low-temperature and low-pressure refrigerant, which is evaporated by an evaporator. Thus, a refrigeration cycle that returns to the compressor is formed. The evaporator supplied with the low-temperature refrigerant is cooled by exchanging heat with the air in the passenger compartment.
[0003]
The expansion valve senses changes in the temperature and pressure of the refrigerant on the evaporator outlet side, and controls the flow rate of refrigerant supplied to the evaporator inlet side based on the temperature rise and fall pressure of the temperature sensing part. And a valve portion to be configured. The valve portion includes a valve hole formed in a wall provided so as to block the refrigerant passage in the middle of a refrigerant passage communicating the refrigerant inlet for receiving the high-pressure refrigerant and the refrigerant outlet for supplying the low-pressure refrigerant, It consists of the valve body provided so that contact and separation were possible facing the hole. The valve body is urged by a spring in a direction to close the valve hole, and is controlled by a temperature sensing unit via a shaft to control the valve opening.
[0004]
Such an expansion valve is attached to the inlet pipe and outlet pipe of the evaporator, but the piping work between the expansion valve and the evaporator is very complicated, so the expansion valve is integrated with the evaporator to perform piping work. It has been proposed to mitigate.
[0005]
As an example, an evaporator with an expansion valve described in JP-A-63-80169 is known. According to this evaporator, a plurality of plates are laminated so that refrigerant flow passages and air circulation spaces are alternately formed, and a plurality of refrigerant flow passages are grouped at both ends of the laminated plates in the refrigerant flow direction. Tanks to be assembled are formed, and these tanks are appropriately connected to form a continuous refrigerant flow. The tank is provided with an expansion valve pipe to which a high pressure pipe for introducing a high pressure liquid refrigerant and a low pressure pipe constituting an evaporator outlet pipe are connected, and one end of the expansion valve pipe extends outside the evaporator. From there, the cylinder block constituting the expansion valve is inserted into the expansion valve pipe. The cylinder block includes a valve section that adiabatically expands the high-pressure liquid refrigerant and a control section that controls the valve body of the valve section by sensing the temperature and pressure of the refrigerant at the evaporator outlet.
[0006]
The pipe for the expansion valve is provided with a hole for supplying the adiabatic and expanded refrigerant to the evaporator inlet and a hole for allowing the refrigerant at the evaporator outlet to pass through the side wall of the cylinder block communicating with these holes. The refrigerant flow passage is sealed by a seal ring disposed between the expansion valve pipe and the cylinder block.
[0007]
[Problems to be solved by the invention]
However, in the conventional expansion valve, when the expansion valve is inserted into the expansion valve pipe in a state where the seal ring is attached to the groove provided around the cylinder block of the cylindrical body, a hole provided in the expansion valve pipe is not provided. There was a risk of breaking the seal ring, and there was a problem that the assembly of the expansion valve was poor.
[0008]
The present invention has been made in view of these points, and an object thereof is to provide an expansion valve with good assemblability.
[0009]
[Means for Solving the Problems]
In the present invention, in order to solve the above problem, in the expansion valve that is attached to a valve case that is integrally welded adjacent to the inlet side tank and the outlet side tank of the evaporator, the refrigerant in the outlet side tank A temperature sensing part having a diaphragm for sensing the temperature and pressure of the gas, a part constituting a room of the temperature sensing part for introducing the refrigerant in the outlet side tank, a first in which the refrigerant is introduced or led out A valve portion having a body having an outer shape in which the diameter of the portion constituting the refrigerant passage and the portion constituting the second refrigerant passage through which the refrigerant is led out or introduced is successively reduced in stages. There is provided an expansion valve having an opening for introducing the refrigerant in the outlet side tank in a part constituting the room of the temperature part and formed integrally with the lower housing of the temperature sensing part. .
[0010]
According to such an expansion valve, since the diameter of the body is reduced stepwise in a direction away from the temperature sensing part, the body can be mounted simply by placing it on a valve case formed according to this, and a seal ring is attached. Assemblability in the state can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a central longitudinal cross-sectional view of an expansion valve according to the present invention, FIG. 2 is a front view of an evaporator equipped with the expansion valve according to the present invention, and FIG. 3 is a cross-sectional view taken along line aa in FIG.
[0012]
The expansion valve 1 according to the present invention is mounted by being inserted into a shallow valve case 3 integrally formed on the outside of the evaporator 2 and fixed to the valve case 3 with a fixing bracket 4.
[0013]
The evaporator 2 has two plate-like heat exchange panels in which a plurality of refrigerant flow passages and air flow passages are alternately arranged, and two other heat exchange panels arranged on top of each other so as to be integrated. Each of the heat exchange panels is provided with a tank at each end in the fluid flow direction to collect the refrigerant flow passages, and the tanks of adjacent panels are connected to each other so that the refrigerant sequentially flows through the heat exchange panels. It is like that.
[0014]
The illustrated evaporator 2 shows a case where an inlet side tank 5 that receives the refrigerant from the expansion valve 1 and an outlet side tank 6 that collects the evaporated refrigerant are arranged adjacent to each other in parallel. A valve case 3 for mounting the expansion valve 1 is attached to a space between the outlet side tank 6 and the outlet side tank 6.
[0015]
The valve case 3 has a shape that is widened upward in the figure, and a refrigerant inlet pipe 7 that receives a high-pressure liquid refrigerant condensed by a condenser is connected to a side wall thereof. The refrigerant outlet pipe 8 of the evaporator 2 is directly connected to the outlet side tank 6. Further, the valve case 3 has a refrigerant outlet opening 9 for supplying a low-temperature / low-pressure refrigerant adiabatically expanded by the expansion valve 1 at a portion in contact with the inlet side tank 5, and is in contact with the outlet side tank 6. In the portion that has been made, there is provided a refrigerant sensing opening 10 that can sense the temperature and pressure of the refrigerant exiting the evaporator 2.
[0016]
The expansion valve 1 includes a temperature sensing unit that senses the temperature and pressure of the refrigerant in the outlet side tank 6, and a valve unit whose opening degree is controlled according to the temperature and pressure of the refrigerant. The temperature sensing part has an upper housing 11 and a lower housing 12, and the valve part has a body 13 incorporating a valve mechanism. Here, the lower housing 12 and the body 13 of the temperature sensing part are integrally formed cut products. The housing of the temperature sensing part is configured by welding the upper housing 11 to the lower housing 12 integral with the body 13.
[0017]
The body 13 includes a portion constituting a room of the temperature sensing portion, a portion constituting a low-pressure refrigerant passage 14 drilled laterally through the center of the axis, and a high-pressure refrigerant passage 15 formed at the axial position of the lower end portion in the drawing. The part which comprises is has the external shape reduced diameter sequentially in steps. A valve hole 16 is formed in the axial position of the wall separating the low-pressure refrigerant passage 14 and the high-pressure refrigerant passage 15. A ball-shaped valve element 17 is disposed in the high-pressure refrigerant passage 15 so as to be able to advance and retreat in the axial direction with respect to the valve hole 16. The valve element 17 is urged toward the valve hole 16 by a compression coil spring 18. Yes. The lower end of the compression coil spring 18 is received by an adjustment screw 19 screwed into the lower opening of the body 13. The adjustment screw 19 adjusts the set value of the expansion valve 1 at which the valve body 17 starts to open. The set value is adjusted by changing the load of the compression coil spring 18 by the amount of screwing into the body 13. . The valve body 17 is provided with a damping spring 20 that suppresses minute vibrations in the axial direction due to pressure fluctuation of the high-pressure refrigerant. The damping spring 20 is sandwiched between the valve body 17 and the compression coil spring 18 at the center, and the tips of a plurality of legs extending radially outward from the center are in sliding contact with the inner wall of the high-pressure refrigerant passage 15. Has been.
[0018]
A shaft 21 is disposed through the wall separating the room of the temperature sensing section and the low-pressure refrigerant passage 14. The shaft 21 is held on the central axis by a packing 22 fitted in the body 13, is supported so as to be able to advance and retreat in the axial direction, and serves to seal between the chamber of the temperature sensing portion and the low-pressure refrigerant passage 14. ing. The packing 22 is held in the body 13 by press-fitting a washer 23 into the body 13.
[0019]
The temperature sensing part is partitioned into upper and lower rooms by a diaphragm 24. A center disk 25 having good thermal conductivity is disposed in close contact with the diaphragm 24 in the lower room of the temperature sensing unit. The center disk 25 transmits the temperature of the refrigerant in the outlet side tank 6 introduced through the opening 26 formed in the lower housing 12 to the diaphragm 24, and also adjusts the temperature and pressure of the refrigerant in the outlet side tank 6. The corresponding displacement of the diaphragm 24 is transmitted to the valve body 17 via the shaft 21. A plurality of openings 26 for introducing the refrigerant in the outlet side tank 6 are formed in the lower housing 12. On the outer periphery of the center disk 25, a heat transfer ring 27 having good thermal conductivity is fixed to the lower housing 12 by press-fitting its legs into the opening 26. One of the legs of the heat transfer ring 27 protrudes outside through the opening 26 to constitute a temperature sensitive fin 28. When the expansion valve 1 is mounted on the valve case 3, the temperature sensing fin 28 penetrates into the outlet side tank 6 and directly senses the temperature of the refrigerant in the outlet side tank 6. Heat is transmitted to the center disk 25.
[0020]
The upper chamber of the temperature sensing portion is filled with the same gas as the refrigerant, and the gas introduction hole formed in the center of the upper housing 11 is closed by welding a ball 29.
[0021]
Further, when the expansion valve 1 is attached to the valve case 3, O-rings 30, 31, and 32 are arranged on the stepped portion of the body 13 whose diameter is reduced stepwise in a direction away from the temperature-sensing portion. A fluid seal is provided between the room of the temperature section, the room of the temperature sensing section and the low-pressure refrigerant passage 14, and the space between the low-pressure refrigerant passage 14 and the high-pressure refrigerant passage 15.
[0022]
In the expansion valve 1 having the above-described configuration, the temperature of the refrigerant collected in the outlet side tank 6 of the evaporator 2 and exiting from the refrigerant outlet pipe 8 is detected by the temperature-sensitive fin 28, and the heat transfer ring 27 and the center disk 25 are detected. Is transmitted to the diaphragm 24 via. Further, the pressure of the refrigerant in the outlet side tank 6 is transmitted to the diaphragm 24 through the opening 26.
[0023]
Here, when the temperature of the refrigerant in the outlet side tank 6 decreases or the refrigerant pressure increases, the diaphragm 24 is displaced upward. As a result, the shaft 21 and the valve body 17 are pushed by the compression coil spring 18 and moved upward, and the valve opening is reduced. As a result, the refrigerant is introduced from the refrigerant inlet pipe 7 to the valve case 3 and the high-pressure refrigerant passage 15 of the expansion valve 1, and is introduced from the low-pressure refrigerant passage 14 of the expansion valve 1 to the evaporator 2 via the valve case 3 and the inlet-side tank 5. Refrigerant flow decreases.
[0024]
Conversely, when the temperature of the refrigerant in the outlet side tank 6 increases or the refrigerant pressure decreases, the diaphragm 24 is displaced downward. Thus, the shaft 21 and the valve body 17 are controlled to move downward against the urging force of the compression coil spring 18 so that the valve opening is increased. As a result, the flow rate of the refrigerant sent to the evaporator 2 through the valve portion of the expansion valve 1 increases.
[0025]
In the expansion valve 1 of the above embodiment, high-temperature and high-pressure liquid refrigerant is introduced into the refrigerant passage on the lower end side in the figure, and low-temperature and low-pressure refrigerant that is adiabatically expanded from the central refrigerant passage is led out. However, the refrigerant may flow in the opposite direction. In that case, the damping spring 20 can be omitted.
[0026]
【The invention's effect】
As described above, in the present invention, the body of the expansion valve has a button shape whose axial length is shorter than the conventional elongated cylindrical shape and whose diameter is gradually reduced in the direction away from the temperature sensing portion. Therefore, it is easy to mount on a shallow valve case formed integrally with the evaporator, and the assemblability can be improved.
[Brief description of the drawings]
FIG. 1 is a central longitudinal sectional view of an expansion valve according to the present invention.
FIG. 2 is a front view of an evaporator equipped with an expansion valve according to the present invention.
FIG. 3 is a cross-sectional view taken along the line aa in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Expansion valve 2 Evaporator 3 Valve case 4 Fixing metal fitting 5 Inlet side tank 6 Outlet side tank 7 Refrigerant inlet piping 8 Refrigerant outlet piping 9 Refrigerant outlet opening 10 Refrigerant sensing opening 11 Upper housing 12 Lower housing 13 Body 14 Low pressure refrigerant Passage 15 High-pressure refrigerant passage 16 Valve hole 17 Valve element 18 Compression coil spring 19 Adjustment screw 20 Damping spring 21 Shaft 22 Packing 23 Washer 24 Diaphragm 25 Center disk 26 Opening 27 Heat transfer ring 28 Temperature sensitive fin 29 Balls 30, 31 32 O-ring

Claims (6)

In the expansion valve designed to be attached to a valve case welded integrally adjacent to the inlet side tank and the outlet side tank of the evaporator,
A temperature sensing unit having a diaphragm for sensing the temperature and pressure of the refrigerant in the outlet side tank;
A portion constituting a room of the temperature sensing portion for introducing the refrigerant in the outlet side tank, a portion constituting a first refrigerant passage through which the refrigerant is introduced or led out, and a second through which the refrigerant is led out or introduced. A valve portion having a body with an outer shape in which a portion constituting the refrigerant passage is gradually reduced in diameter in stages;
With
The body has an opening for introducing the refrigerant in the outlet side tank in a portion constituting a room of the temperature sensing portion, and is formed integrally with the lower housing of the temperature sensing portion. Expansion valve. The valve portion includes a valve hole formed in a wall separating the first refrigerant passage and the second refrigerant passage, and an axial direction with respect to the valve hole in the second refrigerant passage. A valve body disposed so as to be able to advance and retreat, a spring that biases the valve body toward the valve hole, an adjustment screw that adjusts a load of the spring, a chamber of the temperature sensing portion, and the first refrigerant passage The expansion valve according to claim 1, wherein a shaft that penetrates through a wall that separates the diaphragm and transmits the displacement of the diaphragm to the valve body is disposed on a central axis. The expansion valve according to claim 2, further comprising a heat transfer ring having a plurality of legs that are press-fitted into the opening formed on the circumference and having a good thermal conductivity. 4. The heat transfer ring according to claim 3, wherein one of the leg portions protrudes from the opening to constitute a temperature sensitive fin that directly senses the temperature of the refrigerant in the outlet side tank. The expansion valve described. The expansion valve according to claim 3, further comprising a center disk having good thermal conductivity disposed in contact with the diaphragm of the temperature sensing portion in the heat transfer ring. The valve body is received at the center portion, and the tips of a plurality of leg portions extending radially outward from the center portion are in sliding contact with the inner wall of the second refrigerant passage to suppress the vibration of the valve body in the axial direction. The expansion valve according to claim 2, further comprising a vibration damping member.

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