JP2007278616A - Expansion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manage a high pressure side by an absolute pressure by providing a restriction passage capable of varying a cross-sectional area in response to a pressure and a temperature of an introduced coolant. <P>SOLUTION: A differential pressure control valve is composed of a cylindrical movable valve seat 15, and a valve element 17 arranged in a downstream side and energized in a valve opening direction by a spring 18. The movable valve seat 15 is moved in a direction increasing a set differential pressure in accordance with rising of the temperature, by a temperature sensitive part comprised of a cup like member 26 and a diaphragm 27 sealing wax 28 sensing the temperature of the coolant of the high pressure side. The spring 18 energizing the valve element 17 in the valve opening direction is composed of a pressure sensitive part comprised of a diaphragm 23 and a disc coil 24 sensing a pressure of the coolant of a low pressure side such that a spring load increasing in accordance with rising of the pressure acts in a reducing direction. When the temperature of the high pressure side exceeds a predetermined temperature, a stopper 34 of a displacement transmitting member 32 transmitting displacement of the temperature sensitive part to the movable valve seat 15 abuts on a stepped part 35, and thereby, the pressure of the high pressure side is prevented from exceeding a predetermined pressure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an expansion device used in a refrigeration cycle of a vehicle air conditioner, and more particularly to an expansion device that can be efficiently operated by applying it to a refrigeration cycle using carbon dioxide as a refrigerant.

  In the refrigeration cycle of a vehicle air conditioner, in addition to a refrigeration cycle using a receiver that performs gas-liquid separation of the refrigerant condensed by the condenser and a temperature type expansion valve that expands the separated liquid refrigerant, the refrigerant is condensed by the condenser. A refrigeration cycle using an orifice tube that squeezes and expands a refrigerant and an accumulator that performs gas-liquid separation of the refrigerant evaporated by an evaporator is known. Since the orifice tube is composed of a small-diameter tube, it has an advantage that the structure is simple, the manufacturing cost is low, and the degree of freedom in layout is high. However, unlike the temperature expansion valve, the refrigeration cycle using an orifice tube has a refrigerant flow rate control function because it squeezes and expands the refrigerant only with a small-diameter tube, and operates the refrigeration cycle efficiently in all situations. I can't.

  In contrast, the refrigeration cycle is more efficient by applying it to a refrigeration cycle that uses carbon dioxide as the refrigerant, so that the cross-sectional area of the throttle passage where the refrigerant is throttled can be varied according to the pressure and temperature of the refrigerant at the outlet side of the gas cooler. An expansion device that can be operated well has been proposed (see, for example, Patent Document 1).

  According to the expansion device of this patent document 1, the closed space partitioned by the displacement member (diaphragm) so as to detect the pressure and temperature of the refrigerant introduced from the gas cooler is provided on the upstream side of the valve hole. It has a valve structure in which the valve hole is opened and closed from the upstream side, and in the sealed space, the refrigerant has a density ranging from the saturated liquid density at 0 ° C. to the saturated liquid density at the critical point of the refrigerant. Is enclosed. As a result, when the pressure of the introduced refrigerant is lower than the pressure in the sealed space corresponding to the temperature of the refrigerant, the valve hole is closed, and the pressure of the introduced refrigerant is a predetermined pressure higher than the pressure in the sealed space. When the pressure increases, the valve hole starts to open, and when the differential pressure between the introduced refrigerant pressure and the pressure in the sealed space becomes larger than a predetermined pressure, the opening degree is set according to the differential pressure. As a result, the pressure and temperature of the refrigerant at the gas cooler outlet side are controlled along the optimal control line determined from the refrigerant temperature at the gas cooler outlet side and the pressure at which the coefficient of performance is maximized, and carbon dioxide is used. This enables efficient operation of the refrigeration cycle.

  By the way, in the refrigerating cycle which uses a carbon dioxide as a refrigerant | coolant, since the operating pressure is high, the component which comprises a refrigerating cycle has a pressure | voltage resistant structure so that it can endure high pressure. Further, in a compressor that compresses refrigerant and an expansion device that expands compressed refrigerant, when the refrigerant pressure enters a high-pressure region that is dangerous in terms of pressure resistance, the pressure is controlled to decrease or the pressure is decreased. It has been done to make a structure that can.

  For example, in the expansion device, the pressure on the high pressure side of the refrigerant inlet is compared with the atmospheric pressure, and when the pressure on the high pressure side exceeds a predetermined pressure, the valve is opened to reduce the pressure on the high pressure side Is known (for example, see Patent Document 2). According to this expansion device, the bellows that is open to the atmosphere and is compressed as the refrigerant pressure rises due to the refrigerant pressure introduced to the refrigerant inlet of the expansion device to the outside, and the bellows is opened as the bellows is contracted. And a valve mechanism configured to valve. As a result, the bellows compares the high-pressure side refrigerant pressure introduced into the refrigerant inlet of the expansion device with the atmospheric pressure, and if the refrigerant pressure becomes higher than a predetermined pressure that is dangerous for the refrigeration cycle, the bellows In response, the valve mechanism is proportionally opened to reduce the pressure. In this way, the bellows senses the pressure on the high pressure side of the refrigerant inlet as an absolute pressure and controls the valve mechanism, so that it is possible to prevent the pressure on the high pressure side of the refrigerant inlet from becoming higher than a predetermined pressure to some extent. .

  Further, according to Patent Document 2, there is also disclosed an expansion device having a differential pressure control valve structure that operates with a differential pressure between a refrigerant inlet and a refrigerant outlet instead of sensing the pressure on the high pressure side with an absolute pressure. When the pressure difference between the inlet and the refrigerant outlet exceeds a predetermined pressure, the valve is opened to reduce the pressure at the refrigerant inlet.

In this way, by configuring the expansion device so that the pressure on the high-pressure side is limited, there is no fear that the pressure on the high-pressure side becomes an abnormally high pressure. In addition, the high pressure on the high pressure side is when high refrigeration capacity is required. In such a case, the compressor is operating at the maximum discharge capacity, and the pressure on the high pressure side has a predetermined pressure. Even if it exceeds, there is no need to control the compressor to reduce its discharge pressure, so it is possible to operate the compressor efficiently at high discharge pressure and maintain high refrigeration capacity. Become.
JP-A-9-264622 (FIG. 4) JP 2004-142701 A (FIGS. 2 and 5)

  However, the conventional expansion device includes a sealed space that is closed by a displacement member in order to sense the pressure and temperature of the introduced refrigerant and make the opening variable, and in the sealed space, the Since it is configured to be filled with high pressure, there is a risk of explosion when left in an environment of normal temperature and normal pressure, and high quality control is required. there were.

  In addition, in the conventional expansion device that prevents the pressure on the high pressure side from becoming abnormally high, a device using a bellows can detect and control the pressure on the high pressure side with absolute pressure, but directly receives the high pressure. In the case of the differential pressure control valve structure, the pressure on the high pressure side is equal to the value obtained by adding the pressure on the low pressure side to the pressure difference between the refrigerant inlet and the refrigerant outlet. However, since the pressure on the high pressure side is directly affected by the change in the pressure on the low pressure side, there is a problem that it cannot be managed with absolute pressure.

  The present invention has been made in view of the above points, and includes a throttle passage that can change the cross-sectional area according to the pressure and temperature of the introduced refrigerant without having a high-pressure sealed space. An object of the present invention is to provide an expansion device capable of managing the high pressure side with an absolute pressure while operating with a differential pressure between the pressure on the high pressure side and the pressure on the low pressure side.

  In the present invention, in order to solve the above problem, in an expansion device that squeezes and expands the refrigerant circulating in the refrigeration cycle, the high-pressure side pressure into which the refrigerant is introduced and the low-pressure side pressure from which the expanded refrigerant is derived The differential pressure control valve that acts in the valve opening direction as the differential pressure increases, and senses the temperature of the refrigerant on the high-pressure side, and corrects the set differential pressure of the differential pressure control valve to increase as the temperature increases And a pressure sensing unit that senses the pressure of the refrigerant on the low-pressure side and corrects in a direction in which the set differential pressure of the differential pressure control valve decreases as the pressure increases. An inflating device is provided.

  According to such an expansion device, the pressure sensing part senses the refrigerant pressure on the low pressure side while sensing the refrigerant pressure on the low pressure side while the temperature sensing part senses the refrigerant temperature on the high pressure side and corrects the set differential pressure of the differential pressure control valve. It is configured to correct the set differential pressure of the control valve. Thereby, the differential pressure control valve operates at a differential pressure corresponding to the temperature of the refrigerant on the high pressure side, and the differential pressure is changed according to the pressure on the low pressure side, so that the pressure on the high pressure side is almost equal to the absolute pressure. Can be constant.

  The expansion device of the present invention is configured to set the differential pressure according to the temperature on the high-pressure side and shift the differential pressure by the pressure on the low-pressure side, so that the pressure on the high-pressure side can be made almost constant with absolute pressure. There are advantages.

  By using wax as the temperature sensitive material in the temperature sensitive part, there is no need to fill the sealed space with a refrigerant at a very high pressure, so there is a risk of explosion even if the part is left in an environment of normal temperature and pressure There is no. In addition, since the temperature sensing unit prevents the set differential pressure of the differential pressure control valve from being corrected when the temperature on the high pressure side reaches a predetermined temperature, the temperature on the high pressure side exceeds the predetermined temperature. Even if the pressure increases, the pressure on the high pressure side does not become higher than the set pressure at which the stopper acts, and the high pressure side can be prevented from becoming an abnormally high pressure. Furthermore, since the diaphragm that receives the pressure on the low pressure side is supported by a disc spring from the back side, the bellows that are normally used as pressure sensitive elements are not used, so the expansion device can be made inexpensive. Can be configured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example an expansion device applied to a refrigeration cycle using carbon dioxide as a refrigerant.
FIG. 1 is a system diagram showing a refrigeration cycle to which an expansion device of the present invention is applied.

  The refrigeration cycle includes a compressor 1 that compresses a refrigerant, a gas cooler 2 that cools the compressed refrigerant, an expansion device 3 that squeezes and expands the cooled refrigerant, an evaporator 4 that evaporates the expanded refrigerant, An accumulator 5 that stores excess refrigerant in the cycle and separates the vapor-phase refrigerant from the evaporated refrigerant and sends the refrigerant to the compressor 1; a refrigerant sent from the gas cooler 2; And an internal heat exchanger 6 that performs heat exchange between them. In the figure, arrows indicate the flow of the refrigerant.

  In this refrigeration cycle, the compressor 1 sucks and compresses a refrigerant in a gas phase state to form a high-temperature and high-pressure refrigerant, cools the high-temperature and high-pressure refrigerant with the gas cooler 2, and cools the cooled refrigerant with the expansion device 3. A series of operations in which the low-temperature and low-pressure refrigerant is evaporated by the expansion and the low-temperature and low-pressure refrigerant is evaporated by the evaporator 4 are continuously performed. In the process in which the expansion device 3 expands the refrigerant, the refrigerant is in a gas-liquid two-phase state. When the refrigerant evaporates in the evaporator 4, cooling is performed by taking the latent heat of evaporation from the air in the passenger compartment.

  Further, in the refrigeration cycle using carbon dioxide as a refrigerant, an internal heat exchanger 6 for exchanging heat between the refrigerant at the outlet of the gas cooler 2 and the refrigerant at the inlet of the compressor 1 is provided, and the refrigerant from the gas cooler 2 is placed inside. In general, the refrigerant is further cooled by the heat exchanger 6 to lower the enthalpy of the refrigerant at the inlets of the expansion device 3 and the evaporator 4, thereby improving the refrigerating capacity.

  The internal heat exchanger 6 is provided with a high-pressure passage through which a high-pressure refrigerant introduced from the gas cooler 2 flows and a low-pressure passage through which a low-pressure refrigerant introduced from the accumulator 5 are adjacent. An expansion device 3 is provided at the outlet.

  Specifically, the expansion device 3 is incorporated in the vicinity of the outlet of the high-pressure passage of the internal heat exchanger 6, and the refrigerant that has passed through the high-pressure passage is squeezed and expanded, whereby the refrigerant having a low pressure and low temperature is removed from the evaporator 4. To send to. In addition, the expansion device 3 includes a high temperature side temperature sensing portion, and when the high temperature side temperature sensing portion is incorporated in the internal heat exchanger 6, it is an inlet of the high pressure passage (that is, the outlet of the gas cooler 2). It is arranged in the internal heat exchanger 6 so as to sense the refrigerant temperature or the refrigerant temperature at the outlet of the high-pressure passage (ie the inlet of the expansion device 3).

FIG. 2 is a central longitudinal sectional view showing the configuration of the expansion device according to the embodiment.
The expansion device 3 has a body 11 in which cylindrical cylinders 11 a and 11 b are integrally formed at both ends, and a refrigerant that communicates with an outlet of a high-pressure passage of the internal heat exchanger 6 at a central side portion of the body 11. An inlet 12 is provided. The body 11 also has a movable valve seat holding hole 13 opened in the axial direction at the center thereof, one end of which communicates with the refrigerant inlet 12 and the other end communicates with the refrigerant outlet 14 provided in the cylinder 11b. is doing.

  A movable valve seat 15 having a cylindrical shape is disposed in the movable valve seat holding hole 13 so as to be movable back and forth in the axial direction. The movable valve seat 15 has a hollow portion so that the center forms a valve hole, and a refrigerant introduction hole for introducing a high-pressure refrigerant into the hollow portion at a portion located in a space communicating with the refrigerant inlet 12. 16 is provided.

  A valve body 17 that opens and closes the valve hole of the movable valve seat 15 is disposed in a space communicating with the refrigerant outlet 14. The valve body 17 is held by the cylinder 11b so as to be able to contact and separate from the movable valve seat 15, and is urged by a spring 18 in the valve closing direction. Thus, the movable valve seat 15 and the valve body 17 constitute a differential pressure control valve that opens when the differential pressure between the pressure at the refrigerant inlet 12 and the pressure at the refrigerant outlet 14 exceeds a predetermined pressure, which has a cross-sectional area. It is a throttle passage of the expansion device 3 that can be varied. The end of the spring 18 on the side opposite to the valve body 17 is received by a spring receiving member 19 that is held by the cylinder 11b so as to be movable back and forth in the axial direction. The spring receiving member 19 is in contact with a pressure sensing part that senses the pressure of the refrigerant at the refrigerant outlet 14.

  The pressure-sensitive part includes a lid-like outer housing 21 having a shallow spring accommodating part 20, a cylindrical inner housing 22 having an upper side fixed to the cylinder 11b and a flange part on the lower side of the figure, A thin metallic diaphragm 23 disposed between them is provided, and the outer peripheral edge portions thereof are fixed to each other by full circumference welding. Thereby, the diaphragm 23 receives the pressure of the refrigerant | coolant of the low voltage | pressure side in the refrigerant | coolant outlet 14 via the clearance between the valve body 17 and the spring receiving member 19, and the cylinder 11b. A plurality of, in the illustrated example, four disc springs 24 are stacked in the spring housing portion 20 of the outer housing 21 to support the pressure of the low-pressure side refrigerant received by the diaphragm 23 from the back side. An interference preventing film 25 is disposed between the diaphragm 23 and the disc spring 24. The disc spring 24 has a shape in which the central portion protrudes toward the diaphragm 23, and the central portion is displaced in the axial direction according to the pressure of the refrigerant outlet 14. The displacement is transmitted to the valve body 17 via the spring 18. Therefore, this pressure-sensitive part has a function of correcting the position of the valve body 17 in the axial direction according to the pressure of the refrigerant on the low-pressure side.

  A cylinder 11a located above the body 11 is provided with a temperature sensing unit that senses the temperature of the refrigerant on the high-pressure side. That is, the temperature sensing part is constituted by a cup-shaped member 26, a diaphragm 27 fixed to the opening flange portion of the cup-shaped member 26, and a wax 28 enclosed in an airtight container constituted by these. Yes. A spring 30 is interposed between the opening flange portion of the cup-shaped member 26 and the ring-shaped spring receiving member 29 fixed to the opening end of the cylinder 11a, and a temperature difference is formed in the cylinder 11a. It is made to press against the part 31. The wax 28 is made of a material having a large volume expansion coefficient that expands depending on the temperature. Therefore, the temperature sensing unit has a function of correcting the position of the movable valve seat 15 in the axial direction according to the temperature of the refrigerant on the high pressure side.

  A displacement transmitting member 32 fitted with the movable valve seat 15 is disposed adjacent to the temperature sensing portion, and is urged by a spring 33 so as to always contact the central portion of the diaphragm 27. The spring 33 is set to have a smaller spring load than the spring 30 that is biased so as to push down the temperature sensing portion downward in the drawing. Further, the displacement transmitting member 32 is integrally formed with a stopper 34 in which a portion receiving the spring 33 is extended outward in the radial direction, and the downward movement of the stopper 34 in the figure is formed in the body 11. The stepped portion 35 is regulated.

  Further, an O-ring 36 is provided around the body 11 between the temperature sensing portion and the refrigerant inlet 12, and an O-ring 37 is provided around the body 11 between the refrigerant inlet 12 and the refrigerant outlet 14, An O-ring 38 is provided around the inner housing 22 between the refrigerant outlet 14 and the pressure sensitive part.

Next, in the expansion device 3 having the above configuration, first, the operation of the temperature sensing unit will be described.
3 is a central longitudinal cross-sectional view of the expansion device showing a state when the temperature of the high-pressure side refrigerant is low, FIG. 4 is a central vertical cross-sectional view of the expansion device showing a state when the temperature of the high-pressure side refrigerant is high, and FIG. These are figures which show the relationship between the temperature of a refrigerant | coolant, and a pressure.

  First, in the expansion device 3, the temperature sensing unit senses the temperature of the high-pressure side refrigerant and sets the position of the movable valve seat 15 in the axial direction. That is, if the expansion device 3 shown in FIG. 2 is in the middle temperature range of the refrigerant operating temperature range as the refrigerant temperature on the high-pressure side, the temperature of the refrigerant on the high-pressure side decreases from this medium temperature as shown in FIG. Further, since the volume of the wax 28 of the cup-shaped member 26 contracts and the volume decreases, the diaphragm 27 changes in a direction away from the valve body 17, and the change is transmitted to the movable valve seat 15 via the displacement transmitting member 32. The movable valve seat 15 moves upward in the figure, and the differential pressure control valve changes in the valve opening direction. As a result, the spring 18 urging the valve body 17 in the valve closing direction has a small spring load, and the differential pressure control valve has a set differential pressure when it starts to open due to the differential pressure between the high pressure side and the low pressure side. Get smaller. On the contrary, when the temperature of the refrigerant on the high pressure side is high, the wax 28 of the cup-shaped member 26 expands and the volume increases as shown in FIG. 4, so that the diaphragm 27 shifts in a direction approaching the valve element 17. The change is transmitted to the movable valve seat 15 via the displacement transmitting member 32, the movable valve seat 15 moves downward in the figure, and the differential pressure control valve changes in the valve closing direction. Thereby, the spring 18 that urges the valve body 17 in the valve closing direction has a large spring load, and the differential pressure control valve has a large set differential pressure. Therefore, the differential pressure control valve operates at, for example, a differential pressure ΔP1 when the temperature of the high-pressure side refrigerant is low, and the set differential pressure increases when the temperature of the high-pressure side refrigerant increases, as shown in FIG. Thus, the operation is performed with the differential pressure ΔP2. At this time, the pressure on the high pressure side changes according to the temperature, and changes along the thick solid line shown in FIG.

Next, the operation of the pressure sensitive part in the expansion device 3 will be described.
FIG. 6 is a diagram showing the stroke characteristics of the pressure-sensitive part with respect to the pressure on the low pressure side, and FIG. 7 is a central longitudinal sectional view of the expansion device showing a state when the pressure of the refrigerant on the low pressure side is high.

  First, in the expansion device 3, the pressure sensing unit senses the pressure Px of the refrigerant on the low pressure side, and sets the position of the valve body 17 in the axial direction. That is, in the expansion device 3 shown in FIG. 2, when the temperature of the refrigerant on the low pressure side is sufficiently low (for example, 0 ° C.), the pressure Px is also low (for example, 3.6 MPa). At this time, in the pressure sensitive part, the diaphragm 23 for sensing the pressure Px is displaced toward the differential pressure control valve, and the stroke position is +0.3 mm in the example of FIG. Due to this displacement, the spring 18 is biased in the direction in which the spring load increases, and the differential pressure control valve is corrected in the direction in which the set differential pressure increases.

  As the temperature of the refrigerant on the low pressure side increases, the pressure Px increases accordingly. For example, when the temperature is 20 ° C., the pressure Px becomes about 5.8 MPa, and the pressure sensitive part at that time is as shown in FIG. The diaphragm 23 is displaced to the side opposite to the differential pressure control valve side, and the stroke position is -0.3 mm in the example of FIG. This displacement causes the spring 18 to have a smaller spring load, and the differential pressure control valve is corrected to reduce the set differential pressure.

  The pressure on the high pressure side is higher than the pressure Px on the low pressure side by the differential pressure of the differential pressure control valve, and the value is expressed as an absolute value. By providing a pressure-sensitive part on the low-pressure side and correcting the set differential pressure of the differential pressure control valve according to the fluctuation of the pressure Px on the low-pressure side, the pressure on the high-pressure side is made almost constant as an absolute pressure Can do. For example, in FIG. 5, when the pressure on the high-pressure side is about 11 MPa and the set differential pressure is ΔP2, if the pressure on the low-pressure side is 4.7 MPa, ΔP2 is corrected to 6.3 MPa by the pressure-sensitive portion. If the pressure on the side decreases to 3.6 MPa, ΔP2 is corrected to 7.4 MPa, and if the pressure on the low pressure side increases to 5.8 MPa, ΔP2 is corrected to 5.2 MPa. The absolute value does not change.

Next, a case where the temperature of the high-pressure side refrigerant becomes abnormally high will be described.
FIG. 8 is a central longitudinal sectional view of the expansion device showing a state when the temperature of the high-pressure side refrigerant is high.
If the temperature of the refrigerant on the high-pressure side of the expansion device 3 is in an intermediate temperature state as shown in FIG. 2, the volume expansion of the wax 28 is also moderate. It is pressed against the step portion 31 formed in the cylinder 11a by the spring 30 having a spring load larger than 33, and the position in the axial direction does not change.

  Here, when the temperature of the refrigerant on the high-pressure side rises, the wax 28 in the cup-like member 26 expands in volume, and the diaphragm 27 is displaced toward the differential pressure control valve, so that the set differential pressure increases. It will be corrected. An increase in the set differential pressure means that the pressure on the high-pressure side increases if the pressure on the low-pressure side does not change.

  When the temperature of the refrigerant on the high pressure side further rises and the pressure reaches the set pressure Pmax (12 MPa) in the case of FIG. 5, the stopper 34 of the displacement transmitting member 32 moved downward in the figure due to the expansion of the wax 28. It comes into contact with the stepped portion 35 formed in the body 11.

  When the temperature of the refrigerant on the high-pressure side further rises and the wax 28 tries to move the displacement transmission member 32 further downward in the figure, the displacement transmission member 32 cannot move any further. As a result, the movable valve seat 15 comes to a fixed state. Therefore, when the temperature of the refrigerant on the high-pressure side rises and the pressure exceeds the set pressure Pmax, the temperature sensing unit can correct the set pressure differential so as to further increase the set differential pressure. As a result, even if the temperature rises, the pressure on the high-pressure side never becomes higher than the set pressure Pmax.

In the above-described embodiment, the wax 28 is used as the temperature-sensitive material of the temperature-sensing portion. However, other solid or liquid materials may be used as long as the material has a large volume expansion coefficient.
FIG. 9 is a diagram showing a first example of incorporation into the internal heat exchanger of the expansion device, and FIG. 10 is a diagram showing a second example of incorporation into the internal heat exchanger of the expansion device.

  The expansion device 3 is used by being incorporated in the internal heat exchanger 6. According to the assembly example shown in FIG. 9, the expansion device 3 is incorporated in the internal heat exchanger 6 so that the temperature sensing unit senses the refrigerant temperature at the outlet of the gas cooler 2. That is, the internal heat exchanger 6 has a high-pressure passage 39 through which high-temperature and high-pressure refrigerant introduced from the gas cooler 2 flows, and an inlet at one end and an outlet at the other end are formed close to each other, and the outside (see FIG. The mounting hole 40 of the expansion device 3 is formed so as to communicate with the inlet and outlet of the high-pressure passage 39 from the lower side of the expansion device 3, and the refrigerant passage 41 for sending the refrigerant to the evaporator 4 is formed from the mounting hole 40. ing.

  The expansion device 3 is inserted into the mounting hole 40 of the internal heat exchanger 6 and fixed by an appropriate fixing tool (not shown) so as not to be detached from the mounting hole 40. Thereby, the temperature sensing part of the expansion device 3 is located at the inlet of the high-pressure passage 39 and is exposed to the high-temperature and high-pressure refrigerant introduced from the gas cooler 2 and senses the gas cooler outlet temperature.

  Further, according to the example of incorporation shown in FIG. 10, the expansion device 3 has an internal heat exchange so that the temperature sensing unit senses the refrigerant temperature at the outlet of the internal heat exchanger 6 (that is, the inlet of the expansion device 3). Incorporated into the vessel 6. That is, the internal heat exchanger 6 has a mounting hole 40 formed from the outside (downward in the drawing) so as to communicate with the outlet side end portion of the high-pressure passage 39, and is used for sending the refrigerant from the mounting hole 40 to the evaporator 4. A refrigerant passage 41 is formed.

  The expansion device 3 is inserted into the mounting hole 40 of the internal heat exchanger 6 and fixed by an appropriate fixture. However, in the expansion device 3, the O-ring 36 provided around the body 11 between the temperature sensing portion and the refrigerant inlet 12 is removed. Thereby, the temperature sensing part of the expansion device 3 is introduced into the refrigerant inlet 12 and also into the space where the pressure sensing part is located, as the refrigerant sent into the mounting hole 40 from the high pressure passage 39, and the temperature sensing part Is exposed to a high-temperature and high-pressure refrigerant, and the inlet temperature of the expansion device 3 is sensed.

It is a system diagram which shows the refrigerating cycle to which the expansion apparatus of this invention is applied. It is a center longitudinal cross-sectional view which shows the structure of the expansion apparatus which concerns on embodiment. It is a center longitudinal cross-sectional view of the expansion device which shows a state when the temperature of the refrigerant | coolant of a high voltage | pressure side is low. It is a center longitudinal cross-sectional view of the expansion | swelling apparatus which shows a state when the temperature of the high voltage | pressure side refrigerant | coolant is high. It is a figure which shows the relationship between the temperature of a refrigerant | coolant, and a pressure. It is a figure which shows the stroke characteristic of the pressure-sensitive part with respect to the pressure of the low voltage | pressure side. It is a center longitudinal cross-sectional view of the expansion device which shows a state when the pressure of the refrigerant | coolant of a low voltage | pressure side is high. It is a center longitudinal cross-sectional view of the expansion | swelling apparatus which shows a state when the temperature of the high voltage | pressure side refrigerant | coolant is high. It is a figure which shows the 1st example of integration to the internal heat exchanger of an expansion | swelling apparatus. It is a figure which shows the 2nd example of incorporation to the internal heat exchanger of an expansion | swelling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Gas cooler 3 Expansion apparatus 4 Evaporator 5 Accumulator 6 Internal heat exchanger 11 Body 11a, 11b Cylinder 12 Refrigerant inlet 13 Movable valve seat holding hole 14 Refrigerant outlet 15 Movable valve seat 16 Refrigerant introduction hole 17 Valve body 18 Spring 19 Spring receiving member 20 Spring accommodating portion 21 Outer housing 22 Inner housing 23 Diaphragm 24 Disc spring 25 Film 26 Cup-shaped member 27 Diaphragm 28 Wax 29 Spring receiving member 30 Spring 31 Stepped portion 32 Displacement transmitting member 33 Spring 34 Stopper 35 Stepped portion 36, 37, 38 O-ring 39 High-pressure passage 40 Mounting hole 41 Refrigerant passage

Claims (7)

In an expansion device that squeezes and expands the refrigerant circulating in the refrigeration cycle,
A differential pressure control valve that acts in the valve opening direction as the differential pressure between the pressure on the high pressure side where the refrigerant is introduced and the pressure on the low pressure side where the expanded refrigerant is led out increases,
A temperature sensing unit that senses the temperature of the refrigerant on the high-pressure side and corrects the pressure in a direction in which the set differential pressure of the differential pressure control valve increases as the temperature increases;
A pressure sensing unit that senses the pressure of the refrigerant on the low pressure side and corrects the pressure in a direction in which the set differential pressure of the differential pressure control valve decreases as the pressure increases;
An inflating device comprising:   The differential pressure control valve is supported by the body so as to be able to advance and retreat in the axial direction thereof, and has a cylindrical movable valve seat that moves in the valve closing direction as the temperature on the high pressure side increases by the temperature sensing portion, and the movable A valve body arranged in a biased state in the valve closing direction on the low pressure side of the valve seat and acting so that the biasing force in the valve closing direction decreases as the pressure on the low pressure side increases by the pressure sensing unit. The expansion device according to claim 1, wherein the expansion device is provided.   The temperature sensing part is a cup-shaped member, a diaphragm that closes the opening of the cup-shaped member to form a sealed container, and a center part of which can be displaced in the opening / closing direction of the differential pressure control valve; The expansion device according to claim 2, further comprising a temperature-sensitive material having a large volume expansion coefficient enclosed in a sealed container, and configured to transmit the displacement of the diaphragm to the movable valve seat.   The expansion device according to claim 3, wherein the temperature-sensitive material is a wax.   A displacement transmitting member disposed between the temperature sensing portion and the movable valve seat, fixed to the movable valve seat and urged by the first spring so as to always contact the diaphragm; 4. An inflator according to claim 3.   The temperature sensing portion is disposed on the body of the differential pressure control valve so as to be able to advance and retreat in the axial direction, and is biased in the direction of the differential pressure control valve by a second spring having a spring load larger than that of the first spring. The displacement transmitting member is in contact with the body when the temperature sensing part senses a predetermined temperature and receives the displacement of the diaphragm, and the temperature of the high pressure side 6. The expansion device according to claim 5, further comprising a stopper that does not transmit the displacement of the diaphragm to the movable valve seat when the temperature is higher than the predetermined temperature. The pressure-sensitive portion detects a pressure on the low-pressure side and supports the diaphragm while being in contact with the diaphragm on the side opposite to the side where the valve body is disposed of the diaphragm. The expansion device according to claim 2, further comprising a disc spring arranged in such a manner.

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