JP2004138292A - Expansion valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the noise in passing a refrigerant by preventing the rapid response of a valve element of an expansion valve. <P>SOLUTION: A valve body 30 of this expansion valve 101' has a valve chest 35, and controls a flow rate of the refrigerant from a channel 32c toward an evaporator by switching the flow rate at the valve element 32d and an orifice 32a. The refrigerant returning from the evaporator is passed through the channel 34, and returned to a compressor side. A delay member 50 is fitted to a rod 316' operating the valve element 32d. The negative pressure is applied to the channel 34 in starting the compressor, and a power element opens the valve element 32d, but the rapid valve opening is inhibited by the presence of the delay member 50, and the flowing noise of the refrigerant can be reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an expansion valve used for a refrigeration cycle of a vehicle air conditioner.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an expansion valve used in a refrigeration cycle, there is a so-called thermal expansion valve that controls a flow rate of a refrigerant sent to an evaporator according to a temperature and a pressure of a low-pressure refrigerant discharged from an evaporator.
As this type of expansion valve, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-50617 (see Patent Document 1), it is used in a refrigeration cycle of an air conditioner of an automobile.
[0003]
That is, as shown in FIG. 2, the refrigeration cycle 1 includes a compressor 2 driven by an engine, a condenser 3 connected to a discharge side of the compressor 2, a receiver 4 connected to the condenser 3, It comprises an expansion valve 5 for adiabatically expanding a liquid-phase refrigerant into a gas-liquid two-phase refrigerant, and an evaporator 6 connected to the expansion valve 5.
[0004]
The expansion valve 5 is provided with a high-pressure side passage 5b through which a liquid-phase refrigerant flows into a prismatic aluminum expansion valve body 5a, and a low-pressure side passage 5c through which an adiabatic expanded gas-liquid two-phase refrigerant flows. The high-pressure side passage 5b and the low-pressure side passage 5c communicate with each other through an orifice 7, and a valve body 8 for adjusting the amount of refrigerant passing through the orifice 7 is provided in a valve chamber 8d.
[0005]
In the expansion valve 5, a low-pressure refrigerant passage 5d is formed through the expansion valve main body 5a, and an operating rod 9a is slidably disposed in the low-pressure refrigerant passage 5d. It is driven by a power element unit 9 fixed on the upper part of 5a. The inside of the power element portion 9 is airtightly partitioned by a stainless steel diaphragm 9d, and an upper airtight chamber 9c and a lower airtight chamber 9c 'are formed by an upper cover 9f and a lower cover 9f'. The disk portion 9e at the upper end of the operating rod 9a contacts the diaphragm 9d. Further, in the power element section 9, a tube mounting hole 9g is formed in the center of the upper cover 9f, and a capillary tube 9h is mounted in the tube mounting hole 9g. The lower cover 9f 'is attached to the valve body 5a by screwing, and is fixed to the valve body 5a.
[0006]
Further, a compression coil spring 8a that presses the valve body 8 in the valve closing direction via a support member 8c is provided in a lower portion of the expansion valve main body 5a in the valve chamber 8d. The airtightness is maintained by an O-ring 8e, which is formed by an adjusting screw 8b screwed with 5a. An operating rod 9b that moves the valve body 8 in the valve opening direction by sliding the operating rod 9a is in contact with a lower end of the operating rod 9a.
[0007]
The operating rod 9a in the power element 9 transmits the temperature in the low-pressure refrigerant passage 5d to the upper pressure chamber 9c, and the pressure in the upper pressure chamber 9c changes according to the temperature. For example, when the temperature is high, when the pressure in the upper pressure chamber 9c rises and the diaphragm 9d pushes down the operating rod 9a, the valve body 8 moves in the valve opening direction, and the refrigerant passage amount of the orifice 7 increases, and the evaporator The temperature of 6 is lowered.
[0008]
On the other hand, when the temperature is low, the pressure of the upper pressure 9c drops, the force of the diaphragm 9d pushing down the operating rod 9a is weakened, and the valve body 8 is compressed in the valve closing direction by a compression coil spring 8a urged in the valve closing direction. And the amount of refrigerant passing through the orifice 7 decreases, and the temperature of the evaporator 6 increases.
[0009]
As described above, the expansion valve 5 moves the valve body 8 in accordance with the temperature change in the low-pressure refrigerant passage 5 d to change the opening area of the orifice 7, and adjusts the amount of the refrigerant to be passed to adjust the temperature of the evaporator 6. ing. In the expansion valve 5 of this type, the opening area of the orifice 7 for adiabatically expanding the liquid-phase refrigerant into the gas-liquid two-phase refrigerant is determined by the compression coil spring 8a having a variable spring load that presses the valve body 8 in the valve closing direction. It is set by adjusting the spring load with the adjusting screw 8b.
[0010]
FIG. 3 is a longitudinal sectional view showing another example of the conventional expansion valve, and is shown together with the refrigerant cycle 1. The configuration of the temperature-sensitive drive rod is different from that of FIG. reference). In the expansion valve 101 shown in FIG. 3, a valve body similar to the conventional example shown in FIG. 2 is used as the valve body 30. Basically, the high pressure side passage 32b through which the high pressure refrigerant sent to the evaporator 6 passes is connected to the low pressure side. An orifice 32a formed between the side passage 32c, a spherical valve element 32d arranged to face the orifice 32a from the upstream side of the refrigerant, and the valve element facing the orifice from the upstream side. A biasing means 32e for biasing, a valve member 32f disposed between the biasing means and the valve body for transmitting the biasing force of the biasing means to the valve body 32d, and an evaporator 6 Temperature-sensitive drive that passes through an orifice in which a temperature-sensitive rod and an operating rod disposed between the power element portion 36 that operates according to the temperature of the low-pressure refrigerant sent from the valve and the valve element 32d are integrally formed. Stick 31 The provided the valve body 32d in response to operation of the power element portion 36 by which so as to contact and separate with respect to the orifice 32a, and controls the refrigerant flow through the orifice.
[0011]
The power element portion 36 is provided with a stainless steel diaphragm 36a, which is a flexible thin metal plate, and provided in close contact with each other with the diaphragm 36a interposed therebetween. An upper cover 36d and a lower cover 36h made of stainless steel, which are airtight walls constituting the upper pressure chamber 36b and the lower pressure chamber 36c which are pressure chambers, respectively, and a predetermined refrigerant which is a diaphragm drive medium is sealed in the upper pressure chamber 36b. The lower pressure chamber 36c is provided with a blind plug 36i, and communicates with the low-pressure refrigerant passage 34 through an equalizing hole 36e formed concentrically with the center line of the orifice 32a. Refrigerant vapor from the evaporator 6 flows through the low-pressure refrigerant passage 34, and the passage 34 serves as a passage for a gas-phase refrigerant, and the pressure of the gas-phase refrigerant is applied to the lower pressure chamber 36c via the equalizing hole 36e. Further, a cylindrical mounting seat 362 is formed on the lower cover 36h, and the mounting seat 362 is screwed to the screw hole 361 and fixed to the valve body 30.
[0012]
The temperature-sensitive drive rod 318 is configured separately with its upper end 36k separated, and the temperature-sensitive rod is integrally formed with the operating rod as a small-diameter rod member 316 made of, for example, stainless steel. One end of the upper end 36k which is in contact with the lower surface of the diaphragm 36a is formed in a stopper portion 312 which is enlarged in the radial direction, and the other end forms a projection 315 in the center to form a lower pressure 36c. The large diameter portion 314 is slidably inserted into the large diameter portion 314. Further, the upper end of the rod portion 316 is fitted inside the projection 315 of the large diameter portion 314, and the lower end thereof is in contact with the valve body 32d.
The rod member 316 constituting the temperature sensing rod is driven to move forward and backward across the low-pressure refrigerant passage 34 according to the displacement of the diaphragm 36 a of the power element portion 36, so that the low-pressure side passage 32 c and the low-pressure passage 32 c are moved along the rod member 316. A clearance (gap) communicating between the refrigerant passages 34 is formed, and an O-ring 40 that is in close contact with the outer periphery of the rod member 316 for preventing the communication is arranged in the large-diameter hole 38, and between the two passages. An O-ring 40 is provided. Reference numeral 41 denotes a toothed retaining ring provided on the rod member 316 to prevent the O-ring 40 from moving.
Reference numeral 35 denotes a valve chamber, which is a bottomed chamber formed coaxially with the orifice 32a, communicates with the high-pressure side passage 32b, is sealed by a plug 39, and communicates with the low-pressure side passage 32c via the orifice 32a. I do.
[0013]
[Patent Document 1]
JP 2001-50617 A (page 2, FIG. 7)
[Patent Document 2]
JP-A-2000-304381 (page 3, FIG. 8)
[0014]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional expansion valve, the differential pressure between the upper pressure chamber 36b and the lower pressure chamber 36c in the power element portion 36 becomes large due to the pressure drop in the low-pressure refrigerant passage 34 due to the activation of the compressor 2, and the diaphragm When the rod member 316 is pushed down by the displacement of 36a, the valve element 32d responds quickly, moves away from the orifice 32a, and is controlled to a state where the valve element 32d is almost fully open. As a result, the flow rate of the refrigerant from the receiver 4 to the evaporator 6 through the high-pressure side passage 32b rapidly increases, and the flow noise of the refrigerant may increase.
[0015]
Further, the large amount of the refrigerant flows from the low-pressure refrigerant passage 34 into the lower pressure chamber 36c of the power element 36, so that the pressure difference between the upper pressure chamber 36b and the lower pressure chamber 36c becomes small, and the force for pushing down the rod member 316 is reduced. It weakens, and the valve element 32d is rapidly controlled in the valve closing direction. Due to the response of the valve element 32d, the amount of refrigerant passing through the orifice 32a decreases rapidly, and the flow noise of the refrigerant temporarily decreases. Thereafter, the temperature of the evaporator 6 increases due to the decrease in the amount of the refrigerant passing therethrough, the pressure in the upper pressure chamber 36b rises, the diaphragm 36a pushes down the rod member 316, and the valve body 32d is again controlled in the valve opening direction. Due to the response of 32d, the flow rate of the refrigerant flowing toward the evaporator 6 rapidly increases, and the flow noise of the refrigerant may increase again with the flow of the refrigerant.
[0016]
When the refrigerant flow noise due to the flow of the refrigerant in accordance with the response of the valve element 32d as described above, the refrigerant flow noise is large and the refrigerant flow noise fluctuates.
[0017]
The present invention has been made in view of the above circumstances, and has as its object to prevent a rapid response of a valve body by suppressing the refrigerant from flowing into a power element, and to provide a response in a valve closing direction of the valve body. The present invention is to provide an expansion valve capable of reducing the flow noise of the refrigerant by performing the operation slowly.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, an expansion valve according to the present invention includes a high-pressure side passage, a low-pressure side passage, an orifice communicating between these passages, and a low-pressure refrigerant passage and a valve body disposed to face the orifice. A valve element provided therein, a power element provided outside the valve body having a pressure chamber partitioned by a diaphragm, and a temperature-sensitive element for driving the valve element by displacement of the diaphragm according to a pressure change in the pressure chamber. In a drive rod, an expansion valve in which the opening degree of the orifice is controlled by the valve body,
The temperature-sensitive drive rod is constituted by a rod member, and the rod member includes a suppression member for suppressing a flow rate of the refrigerant flowing into the power element.
[0019]
According to such an expansion valve, the flow rate of the refrigerant flowing toward the power element can be limited by the suppression member, and the temperature transmission to the pressure chamber of the power element can be delayed by the rod member. Since the pressure change occurs slowly, the response of the valve body in the valve closing direction becomes slow, and thus the amount of refrigerant passing through the orifice gradually decreases, so that the pressure rise in the pressure chamber of the power element also becomes slow, and the valve A rapid response of the body in the valve opening direction is avoided, a rapid increase in the refrigerant flow rate can be prevented, and the flow noise of the refrigerant can be reduced.
[0020]
Further, in the expansion valve of the present invention, the suppression member is press-fitted into the rod member and disposed between the low-pressure refrigerant passage and the power element.
According to such an expansion valve, since the suppressing member is press-fitted into the rod member of the conventional expansion valve, the response in the valve closing direction of the valve body can be made slow without significantly changing the configuration of the conventional expansion valve. A good expansion valve can be realized.
[0021]
Still further, in the expansion valve of the present invention, the rod member is press-fitted with the suppressing member, and one end of the rod member is fitted into a projection formed on a stopper portion abutting on the diaphragm, and the other end is the valve body. Is characterized by being in contact with.
According to such an expansion valve, since the rod member is fitted with the stopper portion, the temperature transmission to the pressure chamber of the power element is further delayed, so that the pressure change in the pressure chamber occurs more slowly, The response in the valve closing direction of the valve body can be made slower.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of an expansion valve according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of the expansion valve, in which a refrigeration cycle is omitted.
[0023]
1, the basic configuration is the same as that of the conventional expansion valve shown in FIG. 3, and the same reference numerals as those in FIG. 3 denote the same or equivalent parts. And an orifice 32a formed between a high-pressure side passage 32b and a low-pressure side passage 32c through which a high-pressure refrigerant sent to an evaporator basically passes, and the orifice 32a A spherical valve element 32d disposed so as to face from the upstream side of the refrigerant, an urging means 32e for urging the valve element toward the orifice from the upstream side, and an urging means of the urging means. The valve member 32f disposed between the urging means and the valve body for transmitting the force to the valve body 32d, and operates in accordance with the temperature of the low-pressure refrigerant sent from the evaporator passing through the low-pressure refrigerant passage 34. Power d A rod member 316 'is inserted through the inside of the orifice 32a disposed between the lumen portion 36 and the valve body 32b, and the valve member 32d is moved by the rod member 316' according to the operation of the power element portion 36. The flow of the refrigerant passing through the orifice 32a is controlled by being brought into contact with and separated from the orifice 32a.
[0024]
The rod member 316 'has a stopper portion 312 whose upper end portion 36k is in contact with the lower surface of the diaphragm 36a that divides the power element portion 36 into an upper pressure chamber 36b and a lower pressure chamber 36c, and whose end portion is radially enlarged. A large diameter portion 314 slidably disposed in the lower pressure chamber 36c. The displacement of the diaphragm 36a is transmitted to the valve body 32d via the rod member 316 ', and the large diameter portion 314 of the upper end 36k of the rod member 316' slides in the lower pressure chamber 36c. Supported by The upper end of the rod member 316 'is fitted inside the projection 315 of the large diameter portion 314, and the lower end is in contact with the valve body 32d.
[0025]
Thus, the rod member 316 'is provided with the suppressing member 50 by press-fitting, and the suppressing member 50 is integrally formed of the large-diameter cylindrical portion 50a and the small-diameter cylindrical portion 50b connected thereto, for example, stainless steel or the like. It is formed of a metal such as aluminum and has a through hole 50c at the center. It is press-fitted into the rod member 316 'through the through hole 50c. The large-diameter cylindrical portion 50a is disposed in the pressure-equalizing hole 36e, and the small-diameter cylindrical portion 50b is disposed in the low-pressure refrigerant passage 34. The large-diameter cylindrical portion 50a is pressed into the rod member 316 'while maintaining a predetermined clearance with the valve body 30. I have.
[0026]
According to such a configuration, since the suppression member 50 is disposed between the low-pressure refrigerant passage 34 and the lower pressure chamber 36c of the power element 36, the flow rate of the refrigerant flowing from the low-pressure refrigerant passage 34 into the lower pressure chamber 36c is suppressed. As a result, the pressure difference between the upper pressure chamber 36b and the lower pressure chamber 36c is gradually reduced, and the force for pushing down the rod member 316 'is gradually reduced. Therefore, the valve element 35d responds slowly in the valve closing direction. As a result, the amount of refrigerant passing through the orifice 32a gradually decreases, the refrigerant moves toward the evaporator, the pressure in the upper pressure chamber 36b of the power element 36 increases slowly, and the diaphragm 36 moves the rod member 316 'slowly. By pressing down and avoiding a rapid response of the valve body 32d in the valve opening direction, a rapid increase in the refrigerant flowing toward the evaporator can be prevented, and the flow noise of the refrigerant due to the flow of the refrigerant can be reduced.
[0027]
Further, since one end of the rod member 316 ′ is fitted inside the projection 315 of the large-diameter portion 314, the temperature of the refrigerant in the low-pressure refrigerant passage 34 is transmitted from the rod member 316 ′ to the upper pressure chamber 36 b. This is transmitted to the upper pressure chamber 36b with a longer delay than that performed, which helps to make the response of the valve body 32d slower.
[0028]
Moreover, in the embodiment shown in FIG. 1, it is possible to realize an expansion valve with good assemblability and reduce the refrigerant flow noise without largely changing the configuration of the conventional expansion valve shown in FIG.
[0029]
Although the embodiments have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. That is, in the present embodiment, in the expansion valve shown in FIG. 1, the suppression member 50 may be made of resin instead of metal.
[0030]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, since the rapid response of the valve body at the time of the start of a refrigeration cycle can be avoided, refrigerant | coolant flow volume can be suppressed and refrigerant | coolant flow noise can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing one embodiment of an expansion valve of the present invention.
FIG. 2 is a sectional view showing a configuration of a conventional expansion valve.
FIG. 3 is a cross-sectional view showing the configuration of another conventional expansion valve.
[Explanation of symbols]
30 valve body 32a orifice 32d valve body 34 low-pressure refrigerant passage 36 power element 36a diaphragm 36b upper pressure chamber 36c lower pressure chamber 36e equalizing hole 316 'rod member 50 suppressing member 50a large-diameter cylindrical portion 50b small-diameter cylindrical portion

Claims (3)

A high-pressure side passage, a low-pressure side passage, an orifice communicating between these passages, a valve body having therein a low-pressure refrigerant passage and a valve body disposed to face the orifice, and a pressure chamber partitioned by a diaphragm. A power element provided outside the valve body, a temperature-sensitive drive rod for driving the valve element by displacement of the diaphragm in accordance with a pressure change in the pressure chamber, and an opening degree of the orifice controlled by the valve element. Expansion valve
The expansion valve, wherein the temperature-sensitive drive rod is formed of a rod member, and the rod member includes a suppression member that suppresses a flow rate of the refrigerant flowing into the power element. The expansion valve according to claim 1, wherein the suppression member is press-fitted into the rod member and disposed between the low-pressure refrigerant passage and a power element. 3. The expansion valve according to claim 2, wherein one end of the rod member is fitted into a projection formed on a stopper portion abutting on the diaphragm, and the other end abuts on the valve body.

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