JPH10205926A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize minute flow rate condition, in which noise due to the flow of refrigerant is not generated, and secure oil return to a compressor and prevent hunting sound by a method wherein an annular refrigerant passage, surrounding a valve disc, is formed when the valve disc is positioned at a condition, minimizing the flow rate of the refrigerant. SOLUTION: A valve disc 21 is brought into a condition that the same is entered into a throttling hole 15 under a condition that the flow rate of high- pressure refrigerant, sent into an evaporator 1, is minimized. An annular slight gap is produced between the inner peripheral surface of the throttling hole 15 and the outer surface of the valve disc 21 whereby the annular gap becomes the passage of refrigerant and the refrigerant flows as shown by an arrow sign, shown by broken lines, in a diagram. Accordingly, hunting sound will not be generated even under the minimum flow rate condition and oil, mixed into the refrigerant, is returned into a compressor 2 whereby seizure and the like of the compressor 2 will not be generated. The passing sound of the refrigerant will not be generated substantially whereby the same will not become the source of noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve for adiabatically expanding a refrigerant while controlling the flow rate of the refrigerant sent to an evaporator in a refrigeration cycle.

[0002]

2. Description of the Related Art In general, an expansion valve has a valve seat formed at a mouth of a throttle hole formed by narrowing a cross-sectional area in the middle of a refrigerant flow path through which a high-pressure refrigerant sent to an evaporator passes. The flow rate of the refrigerant sent to the evaporator is controlled by moving the valve body so as to change the distance between the valve body and the valve body that is disposed.

[0003]

Oil for lubricating a compressor disposed in such a refrigeration cycle generally circulates in the refrigeration cycle together with a refrigerant. Therefore, when the flow rate of the refrigerant in the refrigeration cycle is zero, the flow rate of the oil returned to the compressor is also zero, which may cause a failure in which the compressor is burned.

On the other hand, when the flow rate of the refrigerant is extremely small,
A state in which the refrigerant flows and a state in which the valve body is in close contact with the valve seat and the refrigerant flow rate becomes zero may be repeated, and so-called hunting noise may be generated.

Therefore, as a countermeasure for preventing such a problem from occurring, a throttle hole which is fully closed by a valve element is provided in parallel with a throttle hole so that the flow rate of the refrigerant does not become zero when the flow rate of the refrigerant is minimized. There is one in which an extremely fine orifice is provided in a high-pressure refrigerant flow path.

However, when the refrigerant passes through such a small orifice, a "shoe" sound is generated. For example, when the refrigerant is used in an air conditioner (car air conditioner) of an automobile, the noise is generated in a room. There is a disadvantage that the noise is transmitted to the vehicle.

Therefore, the present invention realizes a state of a small flow rate in which no noise is generated by the flow of the refrigerant when the flow rate of the refrigerant is minimized, thereby ensuring oil return to the compressor and preventing hunting noise. An object of the present invention is to provide an expansion valve that can perform pressure reduction.

[0008]

In order to achieve the above object, an expansion valve according to the present invention has a throttle hole formed by narrowing a cross-sectional area in the middle of a refrigerant flow path through which a high-pressure refrigerant fed to an evaporator passes. A valve seat is formed at the mouth of the valve, and the valve body is moved so as to change the interval between the valve seat and a valve body arranged opposite to the valve seat, so that the flow rate of the refrigerant sent to the evaporator is reduced. In the expansion valve to be controlled, an annular refrigerant passage surrounding the valve element is formed when the valve element is positioned in a state where the flow rate of the refrigerant is minimized. .

When the outside diameter of the valve body is smaller than the inside diameter of the throttle hole, and the flow rate of the refrigerant is minimized, the valve body enters the throttle hole. May be.

Alternatively, a stopper may be provided for restricting the valve body from coming into close contact with the valve seat when the valve body is closest to the valve seat.

[0011]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an expansion valve 10 according to a first embodiment of the present invention, which is used, for example, in a refrigeration cycle of a car air conditioner. 1 is an evaporator, 2 is a compressor, 3 is a condenser, and 4 is a liquid receiver.

An inlet end of a low-pressure refrigerant passage 12 formed in a main body block 11 of the expansion valve 10 is connected to an outlet of the evaporator 1, and an outlet end of the high-pressure refrigerant passage 13 is connected to an inlet of the evaporator 1. It is connected to the.

The low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13 are formed in parallel with each other.
Penetrates between the low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13. Further, a temperature sensing chamber 30 is attached to an opening formed so as to pass outward from the low-pressure refrigerant flow path 12.

The high-pressure refrigerant flow path 13 has an intermediate portion formed as a throttle hole 15 having a circular cross-sectional shape and a narrower cross-sectional area, and is formed coaxially with the through-hole 14. Of the upstream opening is chamfered into a tapered shape having an angle of about 30 degrees to form a valve seat 20.

FIG. 1 shows a minimum flow state in which the spherical valve element 21 has entered the throttle hole 15, but in a normal state where the flow rate of the high-pressure refrigerant is more than a certain level, the valve element 21 is not in the valve seat. 20 from the upstream side.

As a result, the narrowest part of the gap between the valve body 21 and the valve seat 20 becomes the throttle portion of the high-pressure refrigerant flow path 13,
The high-pressure refrigerant adiabatically expands in the downstream pipeline from there to the evaporator 1.

The valve body 21 is urged by the compression coil spring 17 in a direction approaching the valve seat 20 (ie, in a closing direction). However, between the valve body 21 and the compression coil spring 17, the valve body 21 is received on one side and the compression coil spring 17 is provided on the other side so as to transmit the urging force of the compression coil spring 17 to the valve body 21. Receiving valve body 16 is interposed.

Reference numeral 18 denotes an adjusting nut which is screwed and attached to the main body block 11 to adjust the urging force of the compression coil spring 17; and 19, an O-ring for sealing between the high-pressure refrigerant flow path 13 and the outside. It is.

The rod 23 inserted into the through hole 14
The upper end reaches the temperature sensing chamber 30, the middle part passes through the through-hole 14 vertically across the low-pressure refrigerant passage 12, and the lower end is welded to the head of the valve 21. Is fixed. Note that the rod 23 is
5 so that a sufficient amount of refrigerant can pass between the inner wall surface and
It is formed thinner than the inner diameter of the throttle hole 15.

Reference numeral 24 denotes an O-ring for sealing between the high-pressure refrigerant flow path 13 and the low-pressure refrigerant flow path 12 at an intermediate portion of the rod 23. They are arranged in close contact. 25 is O-ring 2
4 is a compression coil spring for pressing down so as not to come out.

The temperature sensing chamber 30 has a housing 31 made of a thick metal plate and a diaphragm 3 made of a flexible thin metal plate.
2 and a diaphragm receiving plate 33 disposed facing the center of the lower surface of the diaphragm 32.
One end of the rod 23 is in contact with the center of the lower surface of the (displacement member).

In the temperature sensing chamber 30, the refrigerant passages 12,
A gas in a saturated vapor state, which has the same or similar properties as the refrigerant flowing in the 13, is sealed therein, and the injection hole for gas filling is closed by a stopper 34. 36 is an O-ring for sealing.

A bush 38 made of a plastic material or the like having a low thermal conductivity is fixed to an immovable portion between the low-pressure refrigerant flow path 12 and the temperature-sensitive chamber 30, and the low-pressure refrigerant wraps around the temperature-sensitive chamber 30. Regulated. However, in the bush 38, a ventilation groove 40 for penetrating the low pressure refrigerant flow path 12 and the temperature sensing chamber 30 side is penetrated.

In the expansion valve 10 configured as described above, when the temperature of the low-pressure refrigerant flowing through the low-pressure refrigerant flow path 12 decreases, the temperature of the diaphragm 32 decreases, and the temperature-sensitive chamber 30 decreases.
The saturated vapor gas inside condenses on the inner surface of the diaphragm 32.

Then, the pressure in the temperature sensing chamber 30 is reduced, and the diaphragm 32 is displaced inside the temperature sensing chamber 30, and the diaphragm receiving board 33 is displaced in the axial direction of the rod 23 in the direction of escaping from the rod 23. 23 moves by being pushed by the compression coil spring 17. As a result, the valve element 21 moves toward the valve seat 20 and the flow area of the high-pressure refrigerant is reduced, so that the flow rate of the refrigerant sent into the evaporator 1 is reduced.

When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant passage 12 rises, the valve body 21 is pushed by the rod 23 by the operation reverse to the above, and the valve body 21 is pushed from the valve seat 20 against the urging force of the compression coil spring 17. Since the flow path area of the high-pressure refrigerant increases, the flow rate of the high-pressure refrigerant sent to the evaporator 1 increases.

In this manner, the temperature-sensitive chamber 30 and the rod 2 correspond to the temperature of the low-pressure refrigerant sent from the evaporator 1.
The amount of the high-pressure refrigerant sent to the evaporator 1 is controlled by opening and closing the valve body 20 through the operation of the third operation.

The valve element 21 is spherical as described above.
Its diameter is formed to be slightly smaller than the inner diameter of the throttle hole 15, and when the flow rate of the high-pressure refrigerant is at a minimum, FIG.
, The valve element 21 enters the throttle hole 15.

Then, a small annular gap is formed between the inner peripheral surface of the throttle hole 15 and the outer surface of the valve element 21, and the annular gap serves as a refrigerant passage. Flow, and the flow does not reach zero. The area of the annular refrigerant passage is, for example, 0.7 to 0.9 mm.
²

Therefore, no hunting noise is generated even in the minimum flow rate state, and the oil mixed with the refrigerant is returned to the compressor 2, so that the burn of the compressor 2 does not occur. Further, the refrigerant passage in the minimum flow state is the valve body 21.
Has a ring-shaped cross-section surrounding it, so that almost no passing sound of the refrigerant is generated and does not become a noise source.

FIG. 2 shows an expansion valve 10 according to a second embodiment of the present invention, in which a valve body 21 is formed integrally with a valve body receiver 16 in a rod shape at the head thereof. Other configurations are the same as those of the first embodiment, and have the same functions and effects as those of the first embodiment.

In the first and second embodiments, the sectional area of the refrigerant passage in the minimum flow rate state is determined by the valve 21
Are determined only by the outer diameter of the aperture and the inner diameter of the throttle hole 15, so that the error is small.

FIG. 3 shows an expansion valve 10 according to a third embodiment of the present invention, in which the diameter of the valve body 21 is formed larger than the inner diameter of the throttle hole 15, and the valve body 21 is operated at the minimum flow rate. Seat 2
A stopper 16a for restricting the close contact with zero is provided in the valve body receiver 16.

FIG. 4 shows the valve body receiver 16.
A support hole 16b for supporting the valve body 21 is formed at the center portion, and stoppers 16a are protruded at intervals, for example, at three locations on the outer peripheral portion.

FIG. 5 shows a state in which the flow rate of the refrigerant is at a minimum. At a position immediately before the valve body 21 comes into close contact with the valve seat 20, the stopper 16a comes into contact with the main body block 11, and the surface of the valve body 21 and the valve are closed. An annular refrigerant passage is formed between the seat 20 and the slope. As a result, the same functions and effects as those of the first embodiment can be obtained.

[0036]

According to the present invention, the refrigerant flow does not become zero when the valve body is positioned in a state where the flow of the refrigerant is minimized. Seizure can be prevented and hunting noise can be prevented. In this case, since an annular refrigerant passage surrounding the valve body is formed, no noise is generated by the refrigerant flow.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an expansion valve according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an expansion valve according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of an expansion valve according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a valve body receiver according to a third embodiment of the present invention.

FIG. 5 is a partially enlarged cross-sectional view at the time of a minimum flow rate according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Expansion valve 15 Restriction hole 16 Valve body receiving 16a Stopper 20 Valve seat 21 Valve body

Claims (3)

[Claims] 1. A valve seat is formed at the mouth of a throttle hole formed by narrowing a cross-sectional area in the middle of a refrigerant flow path through which a high-pressure refrigerant sent to an evaporator passes, and the valve seat is disposed opposite to the valve seat. By moving the valve so as to change the distance between the valve body and the expansion valve, the expansion valve is configured to control the flow rate of the refrigerant sent to the evaporator. An expansion valve, wherein an annular refrigerant passage surrounding the valve element is formed when the valve element is positioned. 2. In a state where the outer diameter of the valve element is smaller than the inner diameter of the throttle hole and the flow rate of the refrigerant is minimized, the valve element enters the throttle hole. The expansion valve according to claim 1, wherein 3. The expansion valve according to claim 1, further comprising a stopper for restricting the valve body from coming into close contact with the valve seat when the valve body is closest to the valve seat.