JP2005201484A - Refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exhibit predetermined refrigerating capacity by quickly opening an expansion valve connected to an evaporator on the side of resuming operation after once stopping operation in a refrigerating cycle constituted to switch the operation of a plurality of evaporators. <P>SOLUTION: In this refrigerating cycle 1, a differential pressure regulating valve 60 is provided between the expansion valve 40 and the evaporator 20 to suppress the temperature drop of a body 41 of the expansion valve 40. As a result, when a blower 21 is switched on to operate again the evaporator 20 on the resting side, the body 41 is quickly warmed with a refrigerant evaporated from the evaporator 20, and the temperature sensed by its temperature sensing part 50 quickly rises to open the expansion valve 40. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigeration cycle, and more particularly to a refrigeration cycle that includes a plurality of evaporators and is configured to be able to appropriately switch the presence or absence of operation of each evaporator.

  For example, in an automotive air conditioner, in general, a compressor that compresses a circulating refrigerant, a condenser that condenses the compressed refrigerant, a receiver that stores the refrigerant in the refrigeration cycle and separates the condensed refrigerant into gas and liquid, and a separation A refrigeration cycle is configured by an expansion valve that squeezes and expands the liquid refrigerant that has been expanded, and an evaporator that evaporates the refrigerant expanded by the expansion valve. As the expansion valve, a temperature type expansion valve is used which senses the temperature and pressure of the refrigerant at the outlet of the evaporator and controls the flow rate of the refrigerant sent to the evaporator. The temperature type expansion valve includes, for example, a temperature sensing part that is partitioned by a diaphragm and encloses a working gas similar to the refrigerant, and a valve mechanism that squeezes and expands the refrigerant. Then, by exposing the refrigerant at the evaporator outlet to the diaphragm, a pressure difference is generated between the saturation pressure of the working gas corresponding to the refrigerant temperature at the evaporator outlet in the temperature sensing portion and the saturation pressure of the refrigerant at the evaporator outlet. The opening degree of the valve mechanism is determined by the balance between the difference and the spring force, and the flow rate of the refrigerant sent to the evaporator is controlled.

  In particular, in a luxury car or the like, a refrigeration for a so-called dual air conditioner in which an expansion valve and an evaporator are respectively provided on the front seat side and the rear seat side so that the air conditioning control of the front seat and the rear seat can be individually performed. There is one that employs a cycle, and is configured so that the presence or absence of the operation of each evaporator (ON / OFF of the air conditioning control operation) can be switched as appropriate (for example, Patent Document 1).

  In such a refrigeration cycle, a stop valve that is operated by a solenoid or the like is generally provided so that the refrigerant flows into the evaporator side in the expansion valve. However, since it is expensive to configure the expansion valve as an electronic expansion valve using such a solenoid or the like, there is a method in which it is not necessary to use a stop valve, and it is only necessary to stop the blower to the evaporator. Many domestic automobiles adopt this method. FIG. 7 is a system configuration diagram showing a configuration example of such a refrigeration cycle.

  In such a refrigeration cycle 101, for example, when there is only a driver, the fan 111 blows air to the front seat side evaporator 110, while the blower 121 is stopped and the rear seat side evaporator 120 is not blown. Therefore, the evaporation of the refrigerant in the evaporator 120 is extremely small, and the expansion valve 140 on the rear seat side is almost closed.

  However, in a temperature type expansion valve that does not have a driving means such as a solenoid, generally, the valve portion cannot be completely closed, and some gaps are inevitably formed. Furthermore, since there is a pressure difference between the upstream side (high pressure side) and the downstream side (low pressure side) of the valve portion, a small amount of refrigerant naturally flows. Therefore, the pressure Px0 at the valve outlet portion of the expansion valve 140 toward the evaporator 120 is equal to the evaporation pressure Pe of the evaporator 110 at the front seat side (in this case, the valve outlet portion toward the compressor 102 of the expansion valve 130 at the front seat side). Pressure).

  FIG. 8 is a Mollier diagram showing the state of the refrigerant in such a refrigeration cycle. The horizontal axis represents enthalpy and the vertical axis represents absolute pressure. In the figure, the state when both the evaporator 110 and the evaporator 120 are operated is indicated by a solid line, and the state when the evaporator 120 is stopped and only the evaporator 110 is operated is indicated by a one-dot chain line. Represents.

  As shown in the figure, when both the evaporator 110 and the evaporator 120 are operated, this refrigeration cycle operates along a line indicated by ab-cda in the Mollier diagram. That is, the compressor 102 compresses the gas refrigerant evaporated by the evaporators 110 and 120 (a → b), condenses the high-temperature and high-pressure gas refrigerant by the condenser 103 (b → c), and sends it to the receiver 104. Then, the liquid refrigerant is adiabatically expanded by the expansion valves 130 and 140 (c → d), and the refrigerant that has become a gas-liquid two-phase state by adiabatic expansion is evaporated by the evaporators 110 and 120 ( d → a). When this refrigerant evaporates by the evaporators 110 and 120, latent heat of evaporation is taken from the air in the passenger compartment to cool the air in the passenger compartment. At this time, the expansion valves 130 and 140 are controlled so that the refrigerant at the outlets of the evaporators 110 and 120 has a predetermined superheat degree SH beyond the saturated vapor line.

  When the evaporator 120 is stopped and only the evaporator 110 is operated, the operation is performed along the line indicated by a'-b'-c'-d'-a 'in the Mollier diagram. That is, in this case, since the evaporation amount of the entire refrigeration cycle is lower than when both the evaporator 110 and the evaporator 120 are operated, a relatively large suction force is applied to the operating expansion valve 130. Is added, and the outlet pressure Pe toward the compressor 102 decreases. At the same time, the pressure Px0 at the valve outlet to the evaporator 120 side of the expansion valve 140 connected in parallel also decreases.

  FIG. 9 is a saturated vapor temperature-pressure diagram representing the relationship between the temperature and pressure of the refrigerant in this refrigeration cycle, the horizontal axis represents the refrigerant temperature, and the vertical axis represents the refrigerant pressure. The curve indicated by the thick solid line in the figure indicates the saturated vapor pressure curve of the refrigerant, and the curve indicated by the thin solid line in the figure indicates the relationship between the pressure at which the valve portion of the expansion valve opens and the temperature. That is, the expansion valves 130 and 140 are opened when the refrigerant at the outlets of the evaporators 110 and 120 exceeds the saturation vapor pressure curve and has the superheat degree SH.

  By the way, as shown in FIG. 7, such expansion valves 130 and 140 generally used in automobiles include bodies 131 and 141 having passages flowing from the expansion valves 130 and 140 to the evaporators 110 and 120, and the evaporator 110. , 120 are in contact with and integrated with the temperature sensing parts 132, 142 that sense the pressure and temperature of the refrigerant flowing from the refrigerant. The bodies 131 and 141 are often made of an aluminum material for weight reduction. However, since the aluminum material has good thermal conductivity, it is easily affected by the temperature of the refrigerant flowing inside.

  That is, in this case, a small amount of refrigerant flowing downstream of the valve portion of the expansion valve 140 on the rear seat side is depressurized by the valve portion and is in a wet state, and has a lower temperature than the upstream side of the valve portion. The body 141 is cooled down to a temperature Tx0 related to. On the other hand, since a small amount of refrigerant flowing from the evaporator 120 is returned to the expansion valve 140 without evaporating because the valve portion of the expansion valve 140 is closed, the temperature is low and the body 141 cannot be warmed. Therefore, the temperature of the body 141 is substantially the temperature Tx0. At this time, the temperature sensing unit 142 is originally designed to sense the temperature downstream of the evaporator 120, but the temperature approaches the temperature Tx0 due to heat conduction from the body 141.

When the blower 121 is operated again in this state and air is sent again to the evaporator 120 on the rear seat side, the refrigerant in the evaporator 120 evaporates, and the refrigerant temperature Te at the outlet of the evaporator 120 gradually increases. The temperature sensing part 142 of the expansion valve 140 operates to feel the temperature Te and open the valve.
JP 7-151259 A

  However, in the refrigeration cycle as described above, the gas pressure Pb in the temperature sensing part 142 of the expansion valve 140 is usually designed to be the lowest temperature evaporating pressure touched by the temperature sensing part 142. Immediately after the start of air blowing again, the temperature sensing unit 142 feels the temperature of the body 141 and remains at the temperature Tx0. In this state, the temperature is low, and the expansion valve 140 cannot be opened immediately. Moreover, the expansion valve 140 is closed immediately after the start of re-blowing, and the amount of refrigerant flowing through the outlet of the evaporator 120 is small, so the temperature near the temperature sensing unit 142 does not readily reach the original temperature Te, and the expansion valve 140 It takes time to open the valve. Depending on the state of arrangement of the expansion valve 140, the time during which this refrigerant does not flow may take several minutes. As a result, there is a problem that it takes time until the original ability of the refrigeration cycle 101 is exhibited.

  Such a problem is not limited to an automobile air conditioner as a so-called dual air conditioner, and is considered to occur similarly in a refrigeration cycle that includes a plurality of evaporators and is configured to be able to switch the operation of each evaporator.

  The present invention has been made in view of such points, and in a refrigeration cycle configured to be able to switch the presence or absence of operation of a plurality of evaporators, it is connected to the evaporator on the side where the operation is started again after the operation is temporarily stopped. An object of the present invention is to quickly open the expanded valve so as to exert a predetermined refrigeration capacity.

  In the present invention, in order to solve the above problem, a compressor that compresses the circulating refrigerant, a condenser that condenses the refrigerant compressed by the compressor, and a condenser downstream of the condenser are arranged in parallel to each other. A plurality of expansion devices that squeeze and expand the flowing liquid refrigerant, and are connected to each of the plurality of expansion devices and arranged in parallel to each other, evaporate the refrigerant expanded in each expansion device, and move to the compressor side A plurality of evaporators to be supplied and a blower for ventilating the outer surface of the evaporator, at least one of the plurality of expansion devices being in contact with the body and a body housing an internal valve mechanism And a temperature-type expansion valve having a temperature sensing part for operating the internal valve mechanism. A refrigeration cycle configured to switch the operation of each evaporator by turning on and off the ventilation state to the circulator, and connected to at least one of the expansion devices including a temperature expansion valve In addition, a refrigeration cycle is provided in which a differential pressure valve is provided between the evaporator and the evaporator.

  As used herein, the “expansion device” may include an expansion valve, an orifice tube (fixed throttle expansion device), and the like. Further, the “blower” does not necessarily need to match the number of evaporators as long as it can blow individual evaporators individually. Further, when there are a plurality of temperature type expansion valves, the differential pressure valve may be provided for any one of the temperature type expansion valves, but is preferably provided for all the temperature type expansion valves. .

  In this refrigeration cycle, the evaporator on the side that is ventilated by the blower is in the operating state, and if there is a temperature type expansion valve on the side where the blower is stopped, the temperature type expansion valve is almost closed. The refrigerant hardly flows to the evaporator, and the evaporator is in a resting state. However, because it is configured to switch the presence or absence of operation of each evaporator by turning on and off the ventilation state to each evaporator with a blower, the outlet side of the temperature type expansion valve connected to the stopped evaporator (the inlet side of the evaporator) The refrigerant leaks slightly. Further, since any one of the temperature type expansion valves is deactivated, the evaporation amount in the evaporator is lowered in the entire refrigeration cycle, and the flow rate of the refrigerant flowing into the compressor is reduced. As a result, the pressure on the outlet side (the evaporator inlet side) of the temperature type expansion valve connected to the stopped evaporator decreases, and the temperature of the refrigerant leaking there decreases. This temperature is transmitted through the body to the temperature sensing part that is in contact with the temperature by heat conduction. Therefore, when the refrigerant temperature on the outlet side of the temperature type expansion valve connected to the stopped evaporator is low, the temperature type expansion valve maintains the closed state.

  However, according to this refrigeration cycle, since the differential pressure valve is provided between the temperature type expansion valve and the evaporator, the pressure on the upstream side of the differential pressure valve, that is, the outlet side of the temperature type expansion valve is made higher than the pressure on the evaporator side. As a result, the temperature on the outlet side of the thermal expansion valve can be kept higher than when there is no differential pressure valve. As a result, the temperature of the body of the temperature type expansion valve, and hence the temperature sensed by the temperature sensing unit, can be kept high, and when the blower is turned on to operate the evaporator on the paused side again, the temperature sensing unit The temperature to be sensed can be quickly raised to open the temperature type expansion valve.

  According to the refrigeration cycle of the present invention, by providing the differential pressure valve between the temperature type expansion valve and the evaporator, the temperature on the outlet side of the temperature type expansion valve and thus the temperature sensing part can be kept high. it can. As a result, it is possible to quickly open the temperature type expansion valve connected to the evaporator on the side where the operation is started again after pausing the operation, thereby exhibiting a predetermined refrigeration capacity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
First, a first embodiment of the present invention will be described. In the present embodiment, the refrigeration cycle of the present invention is applied to an automotive air conditioner, and FIG. 1 is a system configuration diagram of the refrigeration cycle.

  As shown in the figure, the refrigeration cycle 1 is configured as a refrigeration cycle for a so-called dual air conditioner capable of independent room temperature control between the front seat and the rear seat in the vehicle interior. The refrigeration cycle 1 includes a compressor 2, a condenser 3, a receiver 4, a front seat evaporator 10, an expansion valve 30 and a blower 11, a rear seat evaporator 20, an expansion valve 40, a blower 21, and the like. The evaporator 10, the expansion valve 30 and the blower 11 on the front seat side and the evaporator 20, the expansion valve 40 and the blower 21 on the rear seat side are arranged in parallel with each other, and the ventilation state to each evaporator is turned on by the blowers 11 and 21. -It is configured to switch the presence or absence of operation of each evaporator by turning it off.

And in the middle of piping 5 which connects evaporator 20 and expansion valve 40 by the side of the backseat, differential pressure valve 60 for generating back-and-forth differential pressure is connected via a joint which is not illustrated.
Next, the structure of the expansion valve 40 will be described based on the cross-sectional view of FIG.

  The expansion valve 40 is configured as a temperature type expansion valve, and a port 42 that receives a high-temperature / high-pressure liquid refrigerant from the receiver 4 at a side portion of a body 41 formed of an aluminum material, and the expansion valve 40 performs throttle expansion. A port 43 for supplying the low-temperature / low-pressure refrigerant to the evaporator 20, a port 44 for receiving the refrigerant evaporated from the evaporator 20, and a port 45 for returning the refrigerant that has passed through the expansion valve 40 to the compressor 2. . In this expansion valve 40, a port 43 (valve outlet side passage) connected to the evaporator 20 is arranged closer to a temperature sensing unit 50 described later than a port 42 (valve inlet side passage) connected to the receiver 4.

  In a fluid passage communicating from the port 42 to the port 43, a valve seat 46 is formed integrally with the body 41, and on the upstream side of the valve seat 46, a ball-shaped valve body 47 constituting an internal valve mechanism is disposed. ing. In the space in which the valve body 47 is accommodated, a compression coil spring 48 that urges the valve body 47 in a direction to seat the valve body 47 on the valve seat 46 is disposed. The compression coil spring 48 is received by a spring receiver 49. Yes. The spring receiver 49 is fitted to an adjustment screw 80 screwed to the lower end portion of the body 41, and the load of the compression coil spring 48 can be adjusted by adjusting the screwing amount of the adjustment screw 80 into the body 41. I am doing so.

  The expansion valve 40 has an upper housing 51 and a lower housing 52 made of stainless steel, a diaphragm 53 arranged so as to partition a space surrounded by these, and a lower surface of the diaphragm 53. A temperature sensing part 50 constituted by the arranged disk 54 is provided in contact therewith. In the temperature sensitive room sealed by the upper housing 51 and the diaphragm 53, the same refrigerant as that used in the refrigeration cycle is enclosed.

  A shaft 55 that transmits the displacement of the diaphragm 53 to the valve body 47 is disposed below the disk 54. The upper portion of the shaft 55 is held by a holder 56 disposed across a fluid passage communicating between the ports 44 and 45. The holder 56 is provided with a compression coil spring 57 that applies a lateral load to the upper end of the shaft 55 so as to suppress vibration in the longitudinal direction of the shaft 55 due to pressure fluctuation of the high-pressure refrigerant.

  The expansion valve 40 configured as described above is opened when the temperature sensing unit 50 senses the pressure and temperature of the refrigerant returned from the evaporator 20 to the port 44, and when the temperature of the refrigerant is high or low. When the valve body 47 is pushed in the direction and the temperature is low or the pressure is high, the valve opening degree is controlled by moving the valve body 47 in the valve closing direction. On the other hand, the liquid refrigerant supplied from the receiver 4 flows into the space where the valve body 47 is located through the port 42, and is squeezed and expanded by passing through the valve portion in which the valve opening degree is controlled. become. The refrigerant exits from the port 43 and is supplied to the evaporator 20, where it exchanges heat with the air in the passenger compartment and returns to the port 44 of the expansion valve 40. At this time, the expansion valve 40 controls the flow rate of the refrigerant supplied to the evaporator 20 so that the refrigerant at the outlet of the evaporator 20 has a predetermined degree of superheat, so that the refrigerant is completely evaporated from the evaporator 20 in the compressor. Returned to 2.

Since the structure of the expansion valve 30 is the same as the structure of the expansion valve 40 described above, the description thereof is omitted.
Next, the structure of the differential pressure valve 60 will be described based on the cross-sectional view of FIG. FIG. 2A is a cross-sectional view showing the valve closing state, and FIG. 2B is a cross-sectional view showing the valve opening state.

The differential pressure valve 60 includes a body 61 having a stepped cylindrical main body, and a valve body 62 that is supported in the body 61 so as to advance and retreat.
In the figure, the right side is the upstream side in the refrigeration cycle 1, and the left side is the downstream side, and a stepped portion 63 that is reduced in diameter from the upstream side to the downstream side of the body 61 is formed. A flange portion 64 protruding in the inner diameter direction is formed on the step portion 63 of the body 61, and a valve seat 65 is formed by the downstream end face of the flange portion 64.

  On the other hand, the valve body 62 has a long cylindrical main body 66, one end of which extends outwardly to form a valve portion 67 that can be seated on the valve seat 65, and the other end side of the body 61. A disc-shaped guide member 68 that is slidable on the peripheral surface is fitted and mounted coaxially. The guide member 68 is inserted into the reduced diameter portion 69 formed on the other end side of the main body 66 through the insertion hole 68a formed at the center thereof, and then the distal end of the reduced diameter portion 69 is crimped to the main body 66. It is fixed. In the vicinity of the peripheral edge of the guide member 68, a plurality of through holes 68b are formed at equal intervals in the circumferential direction to form a refrigerant passage. A compression coil spring 71 (biasing means) that biases the valve body 62 in the valve closing direction is interposed between the flange portion 64 and the guide member 68. The valve portion 67 is separated from the valve seat 65 when the refrigerant flows in from the upstream side, and the valve body 62 stops at a position where the refrigerant pressure and the load of the compression coil spring 71 are balanced. As the compression coil spring 71, one having rigidity that can adjust the opening of the valve portion so that the differential pressure across the differential pressure valve 60 becomes a predetermined value (for example, 0.1 MPa) is used.

  Returning to FIG. 1, in the refrigeration cycle 1 configured as described above, when the front-seat evaporator 10 and the rear-seat evaporator 20 are operated simultaneously, both the fans 11 and 21 are turned on. Air is sent to the evaporator. At this time, one of the refrigerants branched after passing through the receiver 4 is adiabatically expanded by the expansion valve 30 to be in a gas-liquid two-phase state, and further evaporated by the evaporator 10 to cool the air in the front seat side in the passenger compartment. Then return to the compressor 2. The other of the refrigerant branched after passing through the receiver 4 is adiabatically expanded by the expansion valve 40 to be in a gas-liquid two-phase state. After being depressurized by the differential pressure valve 60, the refrigerant is further evaporated by the evaporator 10 The air on the rear seat side is cooled and returned to the compressor 2. In this case, since the refrigerant evaporates in both the evaporators 10 and 20 and rises in temperature and then returns to the expansion valves 30 and 40, the body 41 of each expansion valve is also substantially at that temperature. As a result, the temperature sensing unit 50 of both expansion valves senses the temperature and controls the valve body 47 to open.

  Further, when the evaporator 20 on the rear seat side is suspended, the blower 21 on the rear seat side is turned off to stop the air blowing to the evaporator 20. At this time, since the evaporation of the refrigerant by the evaporator 20 is almost eliminated and the temperature of the refrigerant is lowered, the temperature sensing unit 50 detects this and controls the valve body 47 in the valve closing direction. Although the operation of the evaporator 20 is stopped by closing the expansion valve 40, there is no means for actively closing the valve portion of the expansion valve 40 just by turning off the blower 21, so the outlet side of the expansion valve 40 ( A small amount of refrigerant leaks to the inlet side of the evaporator.

  And when restarting operation | movement of the evaporator 20, the air blower 21 is turned ON again. In this case, since the temperature drop of the body 41 is suppressed by providing the differential pressure valve 60, the expansion valve 40 is quickly opened.

  That is, when the blower 21 is turned off and the evaporator 20 is stopped, the evaporation amount in the evaporator 20 as the entire refrigeration cycle 1 decreases, and the flow rate of the refrigerant flowing into the compressor 2 decreases. As a result, the pressure on the outlet side of the expansion valve 40 (the inlet side of the evaporator 20) also decreases, and the temperature of the refrigerant leaking there decreases. This temperature is transmitted through the body 41 to the temperature sensing unit 50 that contacts the temperature by heat conduction.

  However, according to the refrigeration cycle 1 of the present embodiment, the pressure Px1 upstream of the differential pressure valve 60, that is, the outlet side of the expansion valve 40 is provided by providing the differential pressure valve 60 between the expansion valve 40 and the evaporator 20. Can be maintained higher than the pressure Pe (equivalent to the pressure Px0) on the outlet side of the evaporator 20 by the pressure difference ΔP. As a result, as shown in FIG. 9, the temperature Tx1 on the outlet side of the expansion valve 40 can be maintained higher than the temperature Tx0 when there is no differential pressure valve 60 by a temperature difference ΔT. Thus, the temperature sensed by the temperature sensing unit 50 can be kept high. At this time, since the pressure sensed by the temperature sensing unit 50 is Px0, when the temperature reaches Tx1, the expansion valve 40 opens with a slight temperature rise. That is, by increasing the pressure on the outlet side of the expansion valve 40 in this way, the expansion valve 40 can be quickly opened and the operation of the evaporator can be started quickly. The pressure difference ΔP can be set by selecting the compression coil spring 71 or the like of the differential pressure valve 60, thereby setting the temperature difference ΔT.

  As a result, when the blower 21 is turned on to operate the evaporator 20 on the paused side again, the body 41 is quickly warmed by the refrigerant evaporated from the evaporator 20, and the temperature sensed by the temperature sensing unit 50 is quickly increased. The expansion valve 40 can be opened by raising it.

  As described above, in the refrigeration cycle 1 of the present embodiment, the operation is temporarily stopped by providing the differential pressure valve 60 between the expansion valve 40 and the evaporator 20 to suppress the temperature drop of the body 41. The operation of the evaporator 20 on the rear seat side can be quickly resumed to exhibit a predetermined refrigeration capacity.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. Since the refrigeration cycle according to the present embodiment is the same as the configuration of the first embodiment except that the installation position of the differential pressure valve is different, the same components are denoted by the same reference numerals. The description is omitted. FIG. 4 is a cross-sectional view showing the differential pressure valve mounting structure of the present embodiment, and FIG.

  As shown in FIG. 4, in the refrigeration cycle of the present embodiment, the differential pressure valve 260 is inserted and fitted into a connection portion between the expansion valve 40 and a pipe 205 that connects the expansion valve 40 and the evaporator 20. It is fixed to the expansion valve 40.

  As shown in FIG. 5, the differential pressure valve 260 has substantially the same structure as the differential pressure valve 60 of the first embodiment, but the upstream end of the cylindrical body 261 has a flange in the outer diameter direction. A locking portion 262 protruding in a shape is formed, and the locking portion 262 is configured to be locked to the tip of the pipe 205. The pipe 205 has a cylindrical shape, and a flange portion 206 is formed near the tip of the pipe 205 so as to be caulked in the axial direction and project in the outer diameter direction.

  When connecting the pipe 205 to the body 41 of the expansion valve 40, first, the differential pressure valve 260 is inserted into the tip of the pipe 205 from its downstream tip. At this time, the differential pressure valve 260 is fitted and fixed in a state where the locking portion 262 is locked to the tip of the pipe 205.

  Then, in a state where the pipe 205 and the differential pressure valve 260 are integrated in this way, an O-ring 207 for sealing is extrapolated to the distal end portion of the pipe 205, and in this state, the pipe 205 is inserted into the expansion valve 40 from the distal end side. To do. At this time, the flange portion 206 is locked to a step portion provided at the opening end portion of the port 43 of the expansion valve 40 with the O-ring 207 interposed. In this state, the pipe 205 is fixed to the expansion valve 40 from the outside of the flange portion 206 using a fastener (not shown).

At this time, the valve portion 67 of the differential pressure valve 260 is configured to be disposed in the vicinity of the outer peripheral surface of the body 41 of the expansion valve 40, more specifically, slightly outside the outer peripheral surface.
Also in the refrigeration cycle of the present embodiment, a differential pressure valve 260 is provided between the expansion valve 40 and the evaporator 20. For this reason, it is possible to suppress the temperature drop of the body 41 when the evaporator 20 is paused. As a result, the operation of the evaporator 20 on the rear seat side once paused is quickly resumed, and a predetermined refrigeration capacity is obtained. It can be demonstrated.

  Further, since the differential pressure valve 260 is fixed by being inserted into and fitted to the distal end portion of the pipe 205, the differential pressure valve 260 can be directly incorporated into a connection structure between the existing pipe and the expansion valve. That is, it is not necessary to divide the pipe 205 in the middle as in the case where the differential pressure valve 60 is provided in the middle of the pipe 5 in the first embodiment. Further, a joint or the like for connecting to the pipe 205 is not necessary, and the number of parts can be reduced and the assembly work can be made more efficient than in the first embodiment.

Furthermore, since the valve portion of the differential pressure valve 260 is disposed slightly outside the outer peripheral surface of the expansion valve 40, the region where the refrigerant temperature decreases can be positioned outside the expansion valve 40. As a result, it is possible to prevent or suppress the influence of the decrease in the refrigerant temperature due to the reduced pressure on the body 41.
[Third Embodiment]
Next, a third embodiment of the present invention will be described. The refrigeration cycle according to the present embodiment is the same as the configuration of the first embodiment except that an orifice tube is provided instead of a temperature expansion valve as an expansion device on the front seat side. Similar components are denoted by the same reference numerals and the description thereof is omitted. FIG. 6 is a system configuration diagram of the refrigeration cycle.

  As shown in the figure, in the refrigeration cycle 301, an orifice tube 330 is provided between the condenser 3 and the evaporator 10. Here, the high-temperature / high-pressure liquid refrigerant is squeezed and expanded to convert the low-temperature / low-pressure refrigerant into the evaporator 10. To supply. Further, there is no receiver 4 as in the first embodiment, and an accumulator 304 that separates the refrigerant into gas and liquid is provided between the evaporator 10 and the compressor 2. That is, the refrigerant flowing out of the evaporator 10 enters the accumulator 304 where it is separated into a saturated liquid and a saturated gas, and the separated saturated gas returns to the compressor 2.

  In this way, even if the front seat side expansion device is configured by the orifice tube 330, the differential pressure valve 60 is provided for the rear seat side expansion valve 40, so that the present embodiment is similar to the first embodiment. The effects of the invention can be obtained.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the specific embodiment, and it can be changed and modified within the spirit of the present invention. Not too long.

  For example, in the refrigeration cycle of each of the above embodiments, the example in which the body of the expansion valve is made of an aluminum material has been shown. However, like a copper alloy such as brass, the refrigerant has a high thermal conductivity to some extent and flows inside. Even in the case of being formed from a material that is easily affected by the temperature, the effect of the present invention is remarkably exhibited.

  Further, in the second embodiment, the valve portion of the differential pressure valve 260 is disposed slightly outside the outer peripheral surface of the expansion valve 40, but even if it is disposed slightly inside the outer peripheral surface, If the high pressure region is held upstream by the differential pressure valve 260, the effect of the present invention can be obtained to some extent.

  In each of the above embodiments, a refrigeration cycle for a so-called dual air conditioner has been described. However, three or more evaporators and an expansion valve are further provided in parallel, and the operation of the operation can be switched by a blower. Good.

  Further, in each of the above-described embodiments, the example in which the refrigeration cycle of the present invention is applied to an automobile air conditioner is shown, but it is of course possible to apply to a home or commercial air conditioner or other air conditioner. is there.

It is a system configuration figure of the refrigerating cycle concerning a 1st embodiment. It is sectional drawing of the expansion valve which comprises the refrigerating cycle of 1st Embodiment. It is sectional drawing of the differential pressure | voltage valve which comprises the refrigerating cycle of 1st Embodiment. It is sectional drawing showing the attachment structure of the differential pressure | voltage valve which comprises the refrigerating cycle of 2nd Embodiment. It is the A section enlarged view of FIG. It is a system configuration figure of the refrigerating cycle concerning a 3rd embodiment. It is a system block diagram of the conventional refrigeration cycle. It is a Mollier diagram showing the conventional problem. It is a saturated vapor temperature-pressure diagram showing the relationship between the refrigerant | coolant temperature and refrigerant | coolant pressure in a refrigerating cycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,301 Refrigeration cycle 2 Compressor 3 Condenser 4 Receiver 5,205 Piping 10,20 Evaporator 11,21 Blower 30,40 Expansion valve 41 Body 50 Temperature sensing part 60,260 Differential pressure valve 61,261 Body 62 Valve body 65 Valve seat 67 Valve unit 304 Accumulator 330 Orifice tube

Claims (9)

A compressor for compressing the circulating refrigerant;
A condenser for condensing the refrigerant compressed by the compressor;
A plurality of expansion devices that are arranged in parallel to each other downstream of the condenser and squeeze and expand the liquid refrigerant flowing from the condenser side;
A plurality of evaporators connected to each of the plurality of expansion devices and arranged in parallel to each other, evaporating the refrigerant expanded in each expansion device and supplying the refrigerant to the compressor side;
A blower for ventilating the outer surface of the evaporator;
And a temperature type in which at least one of the plurality of expansion devices includes a body that houses an internal valve mechanism, and a temperature sensing part that is disposed to contact the body and operates the internal valve mechanism A refrigeration cycle comprising an expansion valve and configured to switch the presence or absence of operation of each evaporator by turning on and off the ventilation state to each evaporator by the blower,
A refrigeration cycle, wherein a differential pressure valve is provided between at least one of the expansion devices including a temperature expansion valve and the evaporator connected to the expansion device. The differential pressure valve is
A body with a valve seat formed in a cylindrical body;
A valve body having a valve portion that is supported so as to be able to advance and retreat in the body and is movable toward and away from the valve seat;
Urging means for urging the valve body in the valve closing direction;
The refrigeration cycle according to claim 1, wherein an opening degree of the valve portion is adjusted so that a differential pressure before and after becomes a predetermined value.   The differential pressure valve is fixed with respect to the temperature type expansion valve in a state in which the differential pressure valve is inserted into and fitted to a connection part of the temperature type expansion valve in a pipe connecting the temperature type expansion valve and the evaporator. The refrigeration cycle according to claim 2.   The differential pressure valve is inserted and fitted from the front end side of the connection portion with the temperature type expansion valve in the pipe, and is inserted and fixed to the temperature type expansion valve in the fitted state. The refrigeration cycle according to claim 3.   The refrigeration cycle according to claim 3, wherein the valve portion of the differential pressure valve is disposed in the vicinity of the outer peripheral surface of the body of the temperature type expansion valve.   6. The refrigeration cycle according to claim 5, wherein the valve portion of the differential pressure valve is disposed outside the body of the temperature type expansion valve.   2. The temperature expansion valve, wherein a valve outlet side passage connected to the evaporator is disposed closer to the temperature sensing portion than a valve inlet side passage connected to the condenser side. Refrigeration cycle. Reserving the refrigerant condensed in the condenser, and a receiver for separating the refrigerant into gas and liquid,
All of the expansion devices comprise temperature expansion valves that squeeze and expand the liquid refrigerant separated by the receiver, and between at least one of the plurality of temperature expansion valves and the evaporator connected to the temperature expansion valves. The refrigeration cycle according to claim 1, wherein the differential pressure valve is provided. At least one of the expansion devices comprises an orifice tube;
2. The refrigeration cycle according to claim 1, further comprising an accumulator for separating the refrigerant flowing out of the evaporator into gas and liquid between the evaporator to which the orifice tube is connected and the compressor.

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