JP2000028233A - Temperature type expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a valve vibration sound of a temperature type expansion valve on the sub-evaporator side in a refrigerating cycle apparatus wherein a main evaporator and a sub-evaporator are disposed in juxtaposition. SOLUTION: The opening of a restriction passage 17 for subjecting a high- pressure side refrigerant from inlet refrigerant passages 13 and 14 to reduced- pressure expansion is regulated by a valve disk 15. A refrigerant temperature at an evaporator outlet passage 20 is transmitted by a temperature-sensing rod 21 to a first pressure chamber 28 on one side of a diaphragm 22 which displaces the valve disk 15. By a bypass passage 37 provided in a main-body case 12, the high-pressure refrigerant in the inlet refrigerant passages 13 and 14 is introduced directly, with the pressure reduced, into a position of the evaporator outlet passage 20 located in the vicinity of the temperature-sensing rod 21. Even at the time when a low pressure of a cycle lowers it is possible to cool down the temperature-sensing rod 21 to a saturation temperature corresponding to the lowering of the pressure and to maintain the valve disk 15 in a closed state, according to this constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle apparatus in which a main evaporator and a sub-evaporator are arranged in parallel, and a temperature type expansion valve is arranged at a refrigerant inlet of each of the two evaporators. The improvement of the thermal expansion valve.

[0002]

2. Description of the Related Art Conventionally, in order to independently control the air conditioning of a front seat area and a rear seat area in a vehicle interior, air conditioning units are arranged on both the front seat side and the rear seat side in the vehicle interior. In each of the two air conditioning units, a cooling evaporator is housed, and the front and rear evaporators and expansion valves (decompression means) for reducing the pressure of the refrigerant flowing into these evaporators are arranged in parallel. A refrigeration cycle device for vehicle air conditioning is known.

Here, the expansion valve senses the refrigerant temperature at the evaporator outlet to maintain the degree of superheat of the refrigerant at the evaporator outlet at a predetermined value in response to fluctuations in the heat load of the evaporator, and opens the valve. The cycle refrigerant flow rate is adjusted by changing the degree. In such a refrigeration cycle device, an electromagnetic valve is disposed at the refrigerant inlet of the rear evaporator, and the opening and closing of the electromagnetic valve controls the flow of refrigerant into the rear evaporator.

[0004]

Incidentally, in the above-mentioned refrigeration cycle apparatus, the solenoid valve on the rear seat side may be omitted in order to prevent the operation noise of the solenoid valve and to reduce the cost. Even if the solenoid valve is abolished, when the air conditioning unit on the rear seat side stops operating and the ventilation to the rear seat evaporator is stopped, refrigerant evaporation (heat absorption) in the rear seat evaporator almost stops. As a result, the refrigerant passing through the minute gap between the valve element and the valve seat of the expansion valve flows to the evaporator outlet in a saturated state of gas-liquid two-phase, so that the pressure between the pressure chambers on both sides of the diaphragm in the rear expansion valve is reduced. No pressure difference is generated, and the valve element of the expansion valve can be closed by the spring force of the spring means.

However, when only the front air conditioning unit is operated and the rear air conditioning unit is stopped (when the front air conditioning unit is operated alone), the rear seat air conditioning unit is actually used for the following reason. It was found that the valve element of the side expansion valve repeatedly opened and closed and generated vibration noise. That is, if the compressor operation is intermittently controlled (ON-OFF) in order to prevent frost on the front seat evaporator during the sole operation of the front seat air conditioning unit,
Accompanying this, as shown in FIG. 3, fluctuation of the cycle low pressure occurs. In the process of lowering the cycle low pressure due to the operation (ON) of the compressor, the temperature drop of the temperature sensing portion of the rear expansion valve is delayed more than the drop of the low pressure pressure. The pressure (low pressure) of the other pressure chamber is lower than that of the temperature-sensitive pressure chamber. As a result, the valve element of the rear seat expansion valve is slightly opened as shown in part A of FIG.

Thus, with the intermittent operation of the compressor,
Each time, it was found that the valve element of the rear-seat-side expansion valve slightly opened, and at that time, the valve element vibrated and generated a vibration sound.
The present invention has been made in view of the above points, and in a refrigeration cycle apparatus in which a main evaporator and a sub-evaporator are arranged in parallel, it is possible to suppress occurrence of valve vibration noise of a temperature-type expansion valve on the sub-evaporator side. Aim.

[0007]

To achieve the above object, according to the first aspect of the present invention, the inlet refrigerant passages (13, 14) into which the high-pressure side refrigerant is introduced, and the inlet refrigerant passages (13, 14). ), A throttle (17) for decompressing and expanding the refrigerant introduced from), a valve element (15) for adjusting the degree of opening of the throttle (17), and sub-evaporation of the refrigerant decompressed and expanded in the throttle (17). Outlet refrigerant passage (1)
9), an evaporator outlet passage (20) through which the refrigerant that has passed through the sub-evaporator (11) flows, and the evaporator outlet passage (20) is provided to sense the refrigerant temperature of the evaporator outlet passage (20). A temperature sensitive member (21), a pressure responsive member (22) for displacing the valve element (15), and a refrigerant temperature of the evaporator outlet passage (20) formed on one surface side of the pressure responsive member (22). The first pressure chamber (28), which is transmitted through the temperature-sensitive member (21) and acts on the pressure corresponding to the refrigerant temperature, is formed on the other surface side of the pressure-responsive member (22), and is formed at the evaporator outlet passage ( And a second pressure chamber (29) in which the refrigerant pressure of (20) acts. Further, the refrigerant in the inlet refrigerant passages (13, 14) is decompressed to a position near the temperature sensing member (21) in the evaporator outlet passage (20). And a bypass passage (37) for direct introduction.

According to this, the high-pressure liquid refrigerant is reduced in pressure from the inlet refrigerant passages (13, 14) upstream of the valve element (15) through the bypass passage (37), and the evaporator outlet passage (2) is depressurized.
0) can be directly introduced into the vicinity of the temperature sensing member (21). Then, in the passage (20), a part of the refrigerant (two-phase gas-liquid state) flowing from the bypass passage (37) evaporates to cool the temperature-sensitive member (21).

Therefore, even if the cycle low pressure decreases, the refrigerant from the bypass passage (37) can cool the temperature sensing member (21) to a saturation temperature corresponding to the decrease in the low pressure. As a result, the pressures in the first pressure chamber (28) and the second pressure chamber (29) can be made substantially the same, and the valve element (15) can be maintained in a closed state. Therefore, it is possible to prevent a minute opening of the valve body (15) due to a decrease in the low pressure shown in the part A of FIG. 3, and it is possible to suppress the occurrence of valve vibration noise.

[0010] According to the second aspect of the present invention, in the first aspect,
, The inlet refrigerant passages (13, 14), the throttle passage (1)
7), outlet refrigerant passage (19) and evaporator outlet passage (2)
0) that forms an expansion valve main body (12), and the expansion valve main body (12) is provided with a bypass passage () so as to directly connect an inlet refrigerant passage (13, 14) and an evaporator outlet passage (20). 37) is formed, and in the bypass passage (37),
A throttle (38) having an opening area sufficiently smaller than the bypass passage (37) is provided.

Accordingly, even if the diameter of the hole of the bypass passage (37) is relatively large from the viewpoint of workability, the restriction (3) is required.
According to 8), the amount of refrigerant passing through the bypass passage (37) can be limited to a desired amount. Therefore, it is possible to achieve both the securing of the workability of the bypass passage (37) and the suppression of the adverse effect on the cooling performance deterioration due to the flow of the refrigerant passing through the bypass passage (37).

According to the third aspect of the present invention, there is provided a compressor (1) for compressing and discharging a refrigerant, and a condenser (2) for cooling and condensing a gas refrigerant discharged from the compressor (1).
A first expansion valve (6) for reducing and expanding the liquid refrigerant condensed in the condenser (2); and a liquid refrigerant provided in parallel with the first expansion valve (6) and condensed in the condenser (11). A second expansion valve (10) for decompressing and expanding the refrigerant, and a first evaporator (7) for evaporating the refrigerant decompressed and expanded by the first expansion valve (6).
And a second evaporator that is provided in parallel with the first evaporator (7) and evaporates the refrigerant decompressed and expanded by the second expansion valve (10).
And the first and second evaporators (7,
11) One of the main evaporators (7) is mainly used
The other is a sub-evaporator (11) that is selectively used, and one of the first and second expansion valves (6, 10) controls the refrigerant flowing into the main evaporator (7). The main expansion valve (6) for decompressing and expanding, and the other is a sub-expansion valve (10) for decompressing and expanding refrigerant flowing into the sub-evaporator (11). 2. A refrigeration cycle apparatus including the temperature-type expansion valve according to 2.

Further, according to the present invention, a front seat air conditioning unit (4) for air conditioning the front seat side of the vehicle compartment and a rear seat air conditioning unit (8) for air conditioning the rear seat side of the vehicle interior are provided. 3, a main evaporator (7) and a main expansion valve (6) are arranged in a front air conditioning unit (4), and a sub evaporator (8) is installed in a rear air conditioning unit (8). 11)
And a vehicle air conditioner in which the auxiliary expansion valve (10) is arranged.

Specifically, the present invention can be suitably implemented in a refrigeration cycle device according to claim 3 and a vehicle air conditioner according to claim 4. In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the expansion valve of the present invention is applied to a refrigeration cycle device of a vehicle air conditioner. In the drawing, reference numeral 1 denotes a compressor disposed in an engine room of an automobile. It is driven by an automobile engine (not shown) through the electromagnetic clutch 1a and the like to compress and discharge the refrigerant. The refrigerant gas discharged from the compressor 1 is:
It is sent to the condenser 2 in the engine room, where it is cooled by heat exchange with the outside air blown by a cooling fan (not shown), and the refrigerant gas is condensed. This condensed refrigerant is supplied to the receiver 3
Gas and liquid are separated inside, and the liquid refrigerant accumulates in the liquid receiver 3.

Reference numeral 4 denotes a front seat air-conditioning unit for air-conditioning the front seat side in the passenger compartment, which is disposed inside the instrument panel at the front of the passenger compartment. The front-seat air-conditioning unit 4 includes a front-seat electric blower 5, a front-seat thermal expansion valve 6, and a front-seat evaporator (main evaporator) 7 as a cooling heat exchanger. . A temperature sensor 7a is disposed in the air outlet of the front seat evaporator 7, and when the temperature detected by the temperature sensor 7a (evaporator cooling temperature) drops below a predetermined value, the power supply to the electromagnetic clutch 1a is cut off. By stopping the operation of the compressor 1, the frost of the front seat evaporator 7 is prevented.

The front-seat-side expansion valve 6 serves as a pressure reducing means for reducing the high-temperature and high-pressure liquid refrigerant from the receiver 3 to a low-temperature and low-pressure gas-liquid two-phase refrigerant. The flow rate of the refrigerant is adjusted by adjusting the valve opening so that the degree of superheat of the refrigerant at the outlet becomes a predetermined value set in advance. Next, reference numeral 8 denotes a rear-seat air conditioning unit for air-conditioning the rear seat side of the vehicle compartment, which is disposed at a rear portion (a rear seat side portion or the like) of the vehicle compartment. The rear-seat air-conditioning unit 8 includes a rear-seat electric blower 9, a rear-seat temperature expansion valve 10, and a rear-seat evaporator (sub-evaporator) 11 as a cooling heat exchanger. . The rear-seat-side expansion valve 10 serves as a pressure reducing means for reducing the high-temperature and high-pressure liquid refrigerant from the receiver 3 to a low-temperature and low-pressure gas-liquid two-phase refrigerant. The valve opening is adjusted so that the degree of superheat of the refrigerant becomes a predetermined value set in advance, and the flow rate of the refrigerant is adjusted.

The above-described front-seat-side thermal expansion valve 6 and rear-seat-side thermal expansion valve 10 may be of basically the same structure. A point is provided. Hereinafter, the specific structure of the rear seat side temperature type expansion valve 10 will be described in detail with reference to FIG. 2. Reference numeral 12 denotes a main body case of the rear seat side temperature type expansion valve 10, which is formed of a metal such as aluminum into a substantially rectangular parallelepiped shape. . A refrigerant inlet 13 into which a liquid refrigerant flows from the liquid receiver 3 of the refrigeration cycle is opened on the lower right side of the main body case 12.

The refrigerant inlet 13 communicates with a valve body accommodating chamber 14 formed in the lower central portion of the main body case 12, and in this chamber 14, a spherical valve element 15 of the expansion valve 10 and this valve A support member 16 for supporting the body 15 is accommodated.
The valve body 15 and the support member 16 are connected by welding or the like. In this example, an inlet refrigerant passage is constituted by the refrigerant inlet 13 and the valve housing chamber 14.

Reference numeral 17 denotes a throttle passage for reducing the pressure of the liquid refrigerant from the refrigerant inlet 13. A conical valve seat 17a facing the valve body 15 is formed at the inlet of the throttle passage. The adjustment is made by the body 15. In the present embodiment, the throttle passage 17 and the valve element 15 constitute a valve element mechanism 10A of the expansion valve 10. Reference numeral 18 denotes a valve stem disposed through the center of the throttle passage 17, and the lower end thereof is in contact with the spherical valve element 15. Reference numeral 19 denotes an outlet refrigerant passage through which a low-temperature, low-pressure gas-liquid two-phase refrigerant, which has been depressurized through the throttle passage 17, flows, and is formed at a substantially intermediate portion in the vertical direction of the main body case 12. It is connected to the refrigerant inlet of the rear evaporator 11.

Reference numeral 20 denotes an evaporator outlet passage through which the gas refrigerant evaporated in the rear seat evaporator 11 flows. In this embodiment, the evaporator outlet passage is formed so as to penetrate the upper part of the main body case 12 in the left-right direction in a cylindrical shape. . The inlet end (left end in FIG. 2) of the evaporator outlet passage 20 is connected to the refrigerant outlet of the rear seat evaporator 11, and the outlet end (right end in FIG. 2) is connected to the suction port of the compressor 1.

Reference numeral 21 denotes a temperature sensing rod of the rear seat expansion valve 10, which also serves as a displacement transmitting member, and is formed in a cylindrical shape with a metal having good heat conduction such as aluminum. The temperature sensing rod 21 is provided through the evaporator outlet passage 20 and serves as a temperature sensing means for sensing the temperature of the superheated gas refrigerant evaporated in the rear seat evaporator 11. That is, since the temperature sensing rod 21 is located in the flow of the superheated gas refrigerant, the heat of the superheated gas refrigerant is conducted, and the temperature of the superheated gas refrigerant is sensed.

The specific configuration of the temperature sensing rod 21 will be described. A small diameter shaft portion 21 penetrating through the evaporator outlet passage 20 is described.
and a diaphragm stopper portion 21 formed at an end of the small-diameter shaft portion 21a and abutting on a diaphragm 22 described later.
b. The diaphragm stopper 21b is formed integrally with the temperature sensing rod 21 from the upper end side (the end on the side of the diaphragm 22) into a disk-like shape whose outer diameter is enlarged.

Next, the valve drive unit 10B for operating the valve 15 of the rear seat expansion valve 10 will be described.
The upper end of the valve stem 18 abutted against the lower end surface of the temperature sensing rod 21, and an O-ring 23 for sealing is provided in an outer peripheral groove near the lower end of the small diameter shaft portion 21 a of the temperature sensing rod 21. The temperature sensing rod 21 is disposed in the air hole 24 of the main body case 12 in an airtight and slidable manner.

The diaphragm stopper 21b at the upper end of the temperature sensing rod 21 is in contact with a diaphragm (pressure responsive member) 22 disposed on the outermost side of the uppermost part of the main body case 12. Therefore, when the diaphragm 22 is displaced in the vertical direction, the valve element 15 is also displaced via the cylindrical temperature sensing rod 21 and the valve rod 18 in accordance with the displacement. In this example, the valve rod 18 and the temperature sensing rod 21 constitute a displacement transmitting member.

The outer peripheral edge of the diaphragm 22 is supported by being sandwiched between upper and lower case members 25 and 26.
The case members 25 and 26 are made of stainless steel (SUS30).
4) and are integrally joined by welding, brazing, or the like. The lower case member 26 is fixed to the uppermost portion of the main body case 12 by screwing, and the screwed fixing portion is a rubber elastic sealing material (packing) 27.
Is airtight.

The space inside the case members 25 and 26 is partitioned by a diaphragm 22 into an upper chamber (first pressure chamber) 28 and a lower chamber (second pressure chamber) 29. Upper chamber 28
Is connected to a capillary tube 30 for charging the refrigerant, but since the tip of the tube 30 is closed, the upper chamber 28 is a sealed space. The inside of the upper chamber 28 is filled with the same kind of refrigerant gas as the circulating refrigerant in the refrigeration cycle, and the charged gas is the temperature of the superheated gas refrigerant at the evaporator outlet detected by the temperature sensing rod 21 and the temperature of the metal diaphragm 22.
And shows a pressure change according to the temperature of the superheated gas refrigerant.

Therefore, it is preferable that the diaphragm 22 be made of a tough material having high elasticity, good heat conduction, and a good quality, such as stainless steel (SUS304). on the other hand,
The lower chamber 29 is provided with the diaphragm stopper 2 of the temperature sensing rod 21.
1b, the space 31 for pressure introduction formed below the space, and the annular communication passage 32 communicate with the evaporator outlet passage 20, and the evaporator outlet passage 2
A refrigerant pressure of 0 is introduced into the lower chamber 29. That is,
The pressure in the lower chamber 29 is the same as the pressure in the passage 20.

A support mechanism 10C for the spherical valve body 15 is provided at the lowermost part of the main body case 12. A screw hole 33 opened to the outside is provided at the lowermost portion of the main body case 12, and an adjustment nut 34 is screwed and fixed to the screw hole 33. An O-ring 35 for sealing is mounted on the outer peripheral portion of the adjusting nut 34, whereby the gap between the adjusting nut 34 and the screw hole 33 is hermetically sealed.

Reference numeral 36 denotes a coil spring (spring means), one end of which is supported by an adjustment nut 34 and the other end of which is a valve 1
5 is supported by the support member 16. Therefore, the mounting load of the coil spring 36 can be adjusted by adjusting the tightening position of the adjusting nut 34. The rear-seat-side expansion valve 10 is of a type in which the temperature sensing rod 21 is built in the main body case 12 as described above, and is generally box-shaped because its overall shape is substantially box-shaped. The structure up to this is the same for the front seat expansion valve 6.

Next, a unique feature of the rear-seat expansion valve 10 will be described. A bypass passage 37 is provided that directly communicates with the container outlet passage (low-pressure side passage) 20. The outlet of the bypass passage 37 is used to cool the temperature sensing rod 21 by the refrigerant flowing out therefrom.
It is arranged close to.

At the inlet of the bypass passage 37, an orifice (throttle) for restricting the flow of the high-pressure liquid refrigerant flowing from the valve housing chamber 14 into the bypass passage 37 to a predetermined amount or less.
38 are arranged. The orifice 38 is formed of an appropriate metal, and is fixed to the entrance of the bypass passage 37 by press fitting. Here, the hole diameter of the bypass passage 37 is about φ2.0 mm from the viewpoint of workability, whereas the orifice 38 reduces the amount of refrigerant passing through the bypass passage 37 to a very small amount (5 to 10 kg). / H or less), a small hole diameter of about φ0.2 to 0.3 mm is preferable.

Next, the operation of the above configuration will be described.
Now, in the refrigeration cycle apparatus of FIG. 1, when the drive motors of the blower 5 of the front seat air conditioning unit 4 and the blower 9 of the rear seat air conditioning unit 8 are energized to operate both the blowers 5, 9, Air-conditioned air is blown to both evaporators 7, 11 on the front seat side and the rear seat side. When the electromagnetic clutch 1a is energized, the electromagnetic clutch 1a is brought into a connected state, and the compressor 1 is rotationally driven by the power of the vehicle engine.

In this state, the refrigerant is circulated in the cycle by the operation of the compressor 1, and the high-pressure liquid refrigerant is reduced in pressure by the front-seat expansion valve 6 and the rear-seat expansion valve 10 as is well known, and the low-temperature low-pressure gas-liquid The gas-liquid two-phase refrigerant absorbs latent heat of evaporation from the conditioned air in the evaporators 7 and 11 to evaporate, thereby cooling the conditioned air. Here, the specific operation of the rear seat expansion valve 10 will be described as an example.
In the valve drive unit 10B of the expansion valve 10, the temperature of the superheated gas refrigerant at the evaporator outlet in the passage 20 is transmitted to the gas in the upper chamber 28 of the diaphragm 22 via the temperature sensing rod 21 and the metal diaphragm 22. Is done. Therefore, the upper chamber 28
The internal pressure becomes a pressure corresponding to the temperature of the superheated gas refrigerant in the passage 20, while the pressure in the lower chamber 29 of the diaphragm 22 becomes the refrigerant pressure (low pressure) in the passage 20.

Accordingly, the valve body 15 is displaced by the balance between the pressure difference between the two chambers 28 and 29 and the mounting load of the spring 36 for pressing the valve body 15 upward. Then, the opening degree of the throttle passage 17 is adjusted by the displacement of the valve body 15, and the refrigerant flow rate is automatically adjusted. The superheat degree of the gas refrigerant at the outlet of the evaporator is maintained at a predetermined value by the adjusting operation of the refrigerant flow rate.

In the present embodiment, as described above, in the main body case 12 of the rear-seat-side expansion valve 10, the evaporator outlet passage (low-pressure side) extends from the portion of the valve housing chamber 14 upstream of the valve 15. Since the bypass passage 37 communicating directly with the passage (20) is provided, a refrigerant flow bypassing the valve body 15 and the rear seat evaporator 11 is generated. ~ 1
0 kg / h or less).

Therefore, the increase in power of the compressor 1 due to the bypass flow of the refrigerant through the bypass passage 37 can be suppressed to a small amount of about 2 to 5%. Further, of the front and rear air conditioning units 4 and 8, the blower 5 of the front seat side air conditioning unit 4 is provided.
When only the blower 9 of the rear seat side air conditioning unit 8 is stopped, the evaporation of the refrigerant (heat absorption) in the rear seat evaporator 11 is almost stopped, so that the valve body 15 of the rear seat expansion valve 10 is stopped.
The refrigerant passing through the minute gap between the valve and the valve seat 17a flows to the evaporator outlet passage 20 while maintaining the gas-liquid two-phase saturated state. As a result, the refrigerant pressure in the pressure chamber 28 above the diaphragm 22 in the rear seat expansion valve 10 becomes the same as the pressure in the evaporator outlet passage 20, and no pressure difference occurs between the pressure chambers 28 and 29 on both sides. The body 15 can be closed by the spring force of the spring 36.

The operation of the compressor 1 in accordance with the cooling temperature of the front seat evaporator 7 (the temperature detected by the temperature sensor 7a) is described as an actual cycle behavior when the front seat air conditioning unit 4 is operated alone. When the cycle is interrupted, the cycle low pressure fluctuates as shown in FIG. 3, and the valve element 15 of the rear seat expansion valve 10 slightly opens in the process of decreasing the cycle low pressure. The phenomenon occurs.

However, according to this embodiment, the rear seat expansion valve 10 is provided with the bypass passage 37 that directly communicates with the evaporator outlet passage 20 from the portion of the valve housing chamber 14 upstream of the valve 15. Therefore, the high-pressure liquid refrigerant in the valve body accommodating chamber 14 is decompressed by the orifice 38, passes through the bypass passage 37, and flows directly into the evaporator outlet passage 20 near the temperature sensing rod 21.

Then, in the passage 20, the bypass passage 3
A part of the refrigerant (two-phase gas-liquid state) flowing from the evaporator 7 evaporates and cools the temperature sensing rod 21. Here, even if the cycle low pressure decreases as shown in FIG.
The refrigerant always flows in from this, and the flowing refrigerant can immediately cool the temperature sensing rod 21 to a saturation temperature corresponding to the decrease in the low pressure.

As a result, the refrigerant pressure in the pressure chamber 28 on the upper side of the diaphragm 22 can always be made substantially the same as the pressure in the evaporator outlet passage 20 (cycle low pressure) even when the compressor is ON, and the valve body 15 The valve can be kept closed by the spring force of 36. That is, according to the present embodiment, FIG.
A small opening of the valve body 15 due to a decrease in the low pressure as shown in the section A can be prevented, and the generation of valve vibration noise can be suppressed.

(Other Embodiments) In the above embodiment, the orifice 38 for restricting the flow of the high-pressure liquid refrigerant is disposed at the inlet of the bypass passage 37. If it is possible to make the opening cross-sectional area sufficiently small, the orifice 38 can be omitted.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of a vehicle air conditioner to which the present invention is applied.

FIG. 2 is a longitudinal sectional view of the rear-seat-side expansion valve of FIG. 1;

FIG. 3 is an operation explanatory view of the present invention and the conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Rear seat side expansion valve, 11 ... Rear seat side evaporator, 12 ... Body case, 15 ... Valve body, 17 ... Throttle passage, 20 ... Evaporator outlet passage, 21 ... Temperature sensing rod, 22 ... Diaphragm, 28 ... Upper chamber (first pressure chamber), 29 ... Lower chamber (second pressure chamber), 3
7: bypass passage, 38: orifice.

Claims (4)

[Claims] 1. A thermal expansion, which is applied to a refrigeration cycle having a main evaporator (7) and a sub-evaporator (11) connected in parallel and decompresses and expands a refrigerant flowing into the sub-evaporator (11). A valve, wherein an inlet refrigerant passage into which the high-pressure side refrigerant is introduced (13, 14)
A throttle passage (17) for reducing and expanding the refrigerant introduced from the inlet refrigerant passages (13, 14); and a valve body (15) for adjusting the opening of the throttle passage (17).
An outlet refrigerant passage (19) for supplying the refrigerant decompressed and expanded in the throttle passage (17) to the sub-evaporator (11); and an evaporator outlet passage through which the refrigerant passing through the sub-evaporator (11) flows. (20) a temperature-sensitive member (21) provided in the evaporator outlet passage (20) for sensing a refrigerant temperature of the evaporator outlet passage (20);
And a pressure responsive member (22) for displacing the valve body (15).
The refrigerant temperature of the evaporator outlet passage (20) is formed on one surface side of the pressure responsive member (22).
1) a first pressure chamber (28), which is transmitted through the first pressure chamber and receives a pressure corresponding to the refrigerant temperature, and is formed on the other surface side of the pressure responsive member (22), and the evaporator outlet passage (20). And a second pressure chamber (29) on which the refrigerant pressure acts, and a refrigerant in the inlet refrigerant passages (13, 14) is decompressed directly to a position near the temperature-sensitive member (21) in the evaporator outlet passage (20). And a bypass passage (37) for introducing. 2. An expansion valve body (1) forming said inlet refrigerant passages (13, 14), said throttle passage (17), said outlet refrigerant passage (19) and said evaporator outlet passage (20).
2), and the inlet refrigerant passage (13,
The bypass passage (37) is formed so as to directly connect between the evaporator outlet passage (20) and the evaporator outlet passage (20), and the bypass passage (3) is formed in the bypass passage (37).
7. The thermal expansion valve according to claim 1, wherein a throttle (38) having a sufficiently smaller opening area is arranged. 3. A compressor (1) for compressing and discharging a refrigerant, a condenser (2) for cooling and condensing a gas refrigerant discharged from the compressor (1), and a condenser (2) for condensing the refrigerant. A first expansion valve (6) for decompressing and expanding the liquid refrigerant thus obtained, and a second expansion valve provided in parallel with the first expansion valve (6) for decompressing and expanding the liquid refrigerant condensed in the condenser (11). An expansion valve (10), a first evaporator (7) for evaporating the refrigerant decompressed and expanded by the first expansion valve (6), and provided in parallel with the first evaporator (7). A second evaporating the refrigerant decompressed and expanded by the second expansion valve (10);
And one of the first and second evaporators (7, 11) comprises:
A main evaporator (7) used mainly, the other is a sub-evaporator (11) used selectively, and one of the first and second expansion valves (6, 10) is ,
A main expansion valve (6) for decompressing and expanding the refrigerant flowing into the main evaporator (7), and a sub-expansion valve (10) for depressurizing and expanding the refrigerant flowing into the sub-evaporator (11); A refrigeration cycle apparatus, wherein the auxiliary expansion valve (10) is constituted by the temperature-type expansion valve according to claim 1 or 2. 4. The refrigeration cycle apparatus according to claim 3, wherein a front air conditioning unit (4) for air conditioning the front seat side of the vehicle compartment and a rear air conditioning unit (8) for air conditioning the rear seat side of the vehicle interior. The main evaporator (7) and the main expansion valve (6) are arranged in the front seat air conditioning unit (4), and the sub evaporator (11) is installed in the rear seat air conditioning unit (8).
And an air conditioner for a vehicle, wherein the auxiliary expansion valve (10) is arranged.