JPH05231753A - Expansion valve - Google Patents

Abstract

PURPOSE:To control a flow rate of refrigerant with accuracy by installing a leakage sealing means which seals a space between a leakage hole and a high pressure side refrigerant passage when a throttling section is fully closed with a valve disk. CONSTITUTION:When a valve disk 15 is opened, high pressure liquid refrigerant flows past a communication hole 14 from a high pressure side refrigerant flow passage 12 and it is subjected to insulation expansion. The high pressure liquid refrigerant which tends to leak out to the side of a diaphragm 21 passing through a clearance between an actuating rod 30 and a through-hole 19a from the high pressure side refrigerant flow passage 12, is released to a low pressure side refrigerant flow passage 13 passing through a leakage hole 35. When the valve disk 15 fully closes the communication hole 14, a sealing section 31 comes into contact with the offset portions of the through-holes 19a and 19b. As a result, this construction makes it possible to prevent the high pressure liquid refrigerant, which flows past the clearance between the inner surface of a larger- sized portion of the through-hole 19a and the actuating rod 30 from the high pressure side refrigerant flow passage 12, from entering the leakage hole 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve used in a refrigerating cycle such as an automobile air conditioner.

[0002]

2. Description of the Related Art In order to reduce the size of an expansion valve and obtain a large refrigerant flow rate, the diameter of the diaphragm may be reduced and the diameter of the valve body portion may be increased. If the high-pressure refrigerant leaks into the low-pressure chamber of the diaphragm, the diaphragm will not work even if the valve is fully closed, and the cooling will not work at all.

Therefore, conventionally, as shown in FIG. 5 and FIG. 6, the high pressure side refrigerant flow path 8 is formed on the operating rod 83 having the valve body 81 formed at one end and driven forward and backward by the diaphragm 82.
The leak hole 8 for letting out the high-pressure refrigerant that is about to leak from the low-pressure chamber 85 of the diaphragm into the inside of the low-pressure-side refrigerant passage 86.
7 was provided to prevent the high-pressure refrigerant from leaking into the low-pressure chamber 85 (Actual Kaihei 2-96517). The difference between FIG. 5 and FIG. 6 is the presence or absence of the seal member 89 at the inlet of the leak hole 87. 90 is a spacer.

[0004]

However, when the seal member 89 is in contact with the outer periphery of the actuating rod 83 as shown in FIG. 5, it causes considerable motion resistance with respect to the actuating rod 83, resulting in a valve body. There is a drawback that the control of the flow rate of the refrigerant becomes inaccurate due to the difference between the time when 81 moves toward the opening and the time when it moves toward the closing.

However, without the sealing member as shown in FIG. 6, even when the valve body 81 is fully closed, the high pressure side refrigerant flow path 84 passes through the leak hole 87 and the low pressure side refrigerant flow. The high-pressure liquid refrigerant may leak into the passage 86, and the compressor may be damaged by so-called liquid compression at the time of startup.

Therefore, according to the present invention, the high-pressure refrigerant does not leak to the diaphragm side, and there is no difference in the refrigerant flow rate between when the valve is opened and when the valve is closed, or when the valve is fully closed. It is an object to provide an expansion valve that can be operated.

[0007]

In order to achieve the above object, the expansion valve of the present invention has a low pressure connected to an evaporator by passing a high pressure liquid refrigerant supplied from a high pressure side refrigerant passage. A throttle portion for adiabatic expansion of the liquid refrigerant in the side refrigerant passage and a chamber provided in a chamber separated from the high-pressure side refrigerant passage by a partition wall, and operated by temperature fluctuation of the refrigerant gas that exits the evaporator. A diaphragm, a through hole formed in the partition wall so as to penetrate between the throttle portion and the diaphragm, and a valve body for changing the flow passage area of the throttle portion is provided on one end side and the other end. Side is fitted in the through hole and is driven forward and backward by the diaphragm, and the working rod is drilled so that one end opens in the low pressure side refrigerant flow path and the other end opens inside the through hole. With the leak hole provided, When the throttle portion is fully closed by the valve body, for sealing between the leak hole and the high pressure side refrigerant flow passage at a position other than the fitting portion between the through hole and the operating rod. Leak hole sealing means is provided.

[0008]

In the normal operation with the valve body open, the high pressure refrigerant which is about to leak from the high pressure side refrigerant flow path to the diaphragm side through the gap between the operation rod and the through hole is leaked to the operation rod. It escapes to the low-pressure side refrigerant flow path through the hole.

However, when the valve body is fully closed, the leak hole sealing means seals the gap between the leak hole and the high-pressure side refrigerant flow path, so that the high-pressure liquid refrigerant in the high-pressure side refrigerant flow path leaks out. It does not enter inside, and therefore does not leak into the low pressure side refrigerant flow path.

Further, since the leak hole sealing means is provided at a position other than the fitting surface between the through hole and the operating rod, it does not become a resistance against the forward / backward movement of the operating rod.

[0011]

Embodiments will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which 1 is an evaporator,
Reference numeral 2 is a compressor, 3 is a condenser, and 4 is a liquid container containing a high-pressure liquid refrigerant.

Reference numeral 11 denotes a valve body of the expansion valve, and the valve body 11
A high-pressure side refrigerant flow path 12 connected to the outlet of the liquid container 4 and through which a high-pressure liquid refrigerant flows, and a low-pressure side refrigerant flow path 13 connected to the inlet of the evaporator 1 are formed therein.

The low pressure side refrigerant flow passage 13 is formed from the bottom side of the valve main body 11 upward to the vicinity of the central portion of the valve main body 11, and the high pressure side refrigerant flow passage 12 is located immediately above the valve main body 11. It is formed from the side.

Reference numeral 14 is a communication hole which communicates both the flow passages 12 and 13, and narrows the flow passage area of the refrigerant to reduce the refrigerant flow passage 1 on the low pressure side.
3 is a throttle for adiabatically expanding the refrigerant. However, the communication hole 14 is formed to have a sufficiently large diameter to secure the flow rate of the refrigerant.

A valve body 15 having a tapered surface is provided so as to be vertically movable so as to close the communication hole 14 from the low pressure side refrigerant flow path 13 side. Reference numeral 16 denotes a coil spring that biases the valve body 15 in a direction of closing the communication hole 14, and the elastic force of the coil spring 16 pushes the valve body 15 in a direction of closing the communication hole 14.
Reference numeral 17 is a spring receiver.

At the upper end of the valve body 11, the diaphragm chamber 2 is separated from the high pressure side refrigerant passage 12 by a partition wall 18.
0 is provided. Reference numeral 21 denotes a diaphragm made of a thin film plate that can be displaced, and divides the diaphragm chamber 20 into an upper high pressure chamber 22 and a lower low pressure chamber 23.

The high pressure chamber 22 of the diaphragm chamber is provided in the evaporator 1.
A temperature sensing tube 24 provided on the outlet side of the is connected by a capillary tube 25. The temperature sensitive tube 24 detects the temperature of the refrigerant gas that exits the evaporator 1.

A small amount of refrigerant is enclosed in the capillary tube 25. Therefore, the pressure in the high-pressure chamber 22 of the diaphragm chamber changes due to the fluctuation of the temperature of the refrigerant gas leaving the evaporator 1 (generated by the degree of superheat).

On the other hand, the low-pressure chamber 23 of the diaphragm chamber communicates with the outlet side of the evaporator 1, and the inside of the low-pressure chamber 23 is the evaporator 1.
The pressure is equal to the pressure of the refrigerant gas exiting. The diaphragm 21 is displaced by the pressure difference between the high pressure chamber 22 and the low pressure chamber 23.

Reference numeral 30 indicates the movement of the diaphragm 21 to the valve body 1.
5 is an actuating rod for transmission to No. 5. The operating rod 30 passes through the communication hole 14 in the lower portion, and the valve body 15 is integrally formed near the lower end portion thereof. In order to secure the flow rate of the refrigerant, the operating rod 30 is formed so as to have a sufficient gap with respect to the inner diameter of the communication hole 14.

A communication hole 14 is formed in the partition wall 18 of the valve body 11.
And penetrates straight between the center of the diaphragm 21 and
A stepped through-hole having a large diameter portion 19a and a small diameter portion 19b is formed.

The head portion of the operating rod 30 is slidably fitted in the large diameter portion 19a opening to the high pressure side refrigerant flow passage 12 inside with a small clearance. The diameter of the large diameter portion 19a is formed to have the same size as the diameter of the communication hole 14 of the narrowed portion. Therefore, the pressure of the high-pressure side refrigerant acts evenly in both the upper and lower directions to be offset, and does not affect the operation of the valve element 15.

To the small diameter portion 19b of the through hole, an elongated rod 37 whose both ends are in contact with the receiving plate 36 attached to the central portion of the lower surface of the diaphragm 21 and the head of the operating rod 30.
However, it is still slidably fitted with a small clearance.

Reference numeral 35 denotes a leak hole formed in the actuation rod 30, one end of which opens at the lower end of the actuation rod 30 into the low-pressure side refrigerant passage 13 and the other end of which is at the upper end face of the actuation rod 30. It is open.

However, the opening on the upper end side is the rod 3
The opening is formed in an oblique direction by shifting the position from the center so as not to interfere with 7. The outer peripheral portion of the upper end of the actuating rod 30 is formed so as to project like an annular edge, and the through hole 1
The seal portion 31 is in close contact with the step portions 9a and 19b. As shown in FIG. 1, when the valve body 15 fully closes the communication hole 14, the seal portion 31 has through holes 19a,
Close to the step of 19b. As a result, the high pressure side refrigerant flow path 1
The high-pressure liquid refrigerant coming from inside 2 through the gap between the inner surface of the large diameter portion 19a of the through hole and the actuating rod 30 is prevented from entering the leak hole 35.

Since the seal portion 31 is formed on the outer edge of the upper end of the operating rod 30, it does not become a resistance against the forward / backward movement of the operating rod 30. In addition, the operating rod 30 and the rod 37
No other member is provided on the sliding surface portion of the device to resist the forward / backward movement.

FIG. 2 shows a state during normal operation in which the valve body 15 is open. The high-pressure liquid refrigerant passes from the high-pressure side refrigerant flow passage 12 through the communication hole 14 to the low-pressure side refrigerant flow passage 13. Adiabatically expands.

Then, from the high pressure side refrigerant flow path 12 to the operating rod 3
The high-pressure liquid refrigerant that is about to leak to the diaphragm 21 side through the gap between 0 and the through hole 19a is released to the low-pressure side refrigerant passage 13 through the leak hole 35. However, the amount of the refrigerant that enters the low-pressure-side refrigerant flow path 13 through the leak holes 35 is extremely small as a whole, and therefore has almost no effect on the cooling state or the like.

It should be noted that it is not easy to machine the large diameter portion 19a so that the corners of the large diameter portion 19a of the through hole come into close contact with the seal portion 31 of the operating rod 30. Therefore, for example, in FIG.
, The through hole 19 is formed thick as a whole,
The sleeve 11a through which the rod 37 is inserted may be pressed into the valve body.

FIG. 4 shows a second embodiment of the present invention in which the seal portion 31 of the actuating rod 30 is in close contact with the periphery of the high pressure side refrigerant passage 12 side opening of the through hole 19. Is. The through hole 19 has no step, the actuation rod 30 is in direct contact with the receiving plate 36 on the lower surface of the diaphragm 21, and the leak hole 35 is opened on the side surface of the actuation rod 30.

As described above, the seal portion 31 may be provided at a position other than the fitting portion between the through hole 19 and the operating rod 30.

[0032]

According to the expansion valve of the present invention, during normal operation when the valve body is open, the high pressure refrigerant that is about to leak from the high pressure side refrigerant passage to the diaphragm side is released to the low pressure side refrigerant passage. Moreover, when the valve body is fully closed, the high pressure refrigerant does not flow from the high pressure side refrigerant passage into the leak hole formed in the actuation rod, so that liquid compression does not occur when the compressor is started. Since it is not necessary to provide a seal member etc. on the sliding surface of
The operation resistance can be almost eliminated, and the difference in the refrigerant flow rate when the valve is opened and when it is closed can be eliminated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment when a valve is closed.

FIG. 2 is a sectional view of the first embodiment when the valve is open.

FIG. 3 is a cross-sectional view of a modified example of the first embodiment.

FIG. 4 is a sectional view of a second embodiment.

FIG. 5 is a sectional view of a conventional example.

FIG. 6 is a sectional view of a second conventional example.

[Explanation of symbols]

 1 Evaporator 12 High Pressure Side Refrigerant Flow Path 13 Low Pressure Side Refrigerant Flow Path 15 Valve Body 18 Partition Walls 19a, 19b Through Hole 21 Diaphragm 30 Actuating Rod 31 Seal Section 35 Leak Hole

Claims (1)

[Claims] 1. A throttle unit for adiabatically expanding the liquid refrigerant in a low-pressure side refrigerant channel connected to an evaporator by passing a high-pressure liquid refrigerant supplied from a high-pressure side refrigerant channel, A diaphragm that is provided in a chamber separated from the high-pressure side refrigerant flow path by a partition wall and that operates by a change in the temperature of the refrigerant gas that exits the evaporator; and the partition wall that penetrates between the diaphragm portion and the diaphragm. And a valve body for changing the flow passage area of the throttle portion is provided on one end side and the other end side is fitted into the through hole, and is driven forward and backward by the diaphragm. And a leak hole formed in the actuation rod so that one end is opened to the low pressure side refrigerant flow passage and the other end is opened to the inside of the through hole, and the throttle portion is fully closed by the valve body. When the above penetrates Expansion valve, characterized in that a provided a leak hole sealing means for sealing between the leak hole and the high-pressure side refrigerant flow path at a position other than the fitting portion between the actuating rod.