JPH09310937A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the flow rate of refrigerant approximately corresponding to the temperature of the refrigerant sent from an evaporator by disposing a temperature sensitive chamber at the outlet of an air stream flowing along heat transfer fins of an evaporator, where a valve body is driven by a diaphragm forming a part of an airtight wall of the temperature sensitive chamber. SOLUTION: In an expansion valve 20 which is used together with an evaporator in a refrigeration cycle for an air conditioner of automobile, high pressure refrigerant is sent from a high pressure refrigerant inlet 22 toward a refrigerant outlet 23 to feed the refrigerant into the evaporator, while the refrigerant is being adiabatically expanded at a throttling orifice 24, and a valve body 25 is displaced corresponding to the pressure in a temperature sensitive chamber 30 through a diaphragm 31 to vary the flow rate of the high pressure refrigerant. In this case, the chamber 30 is provided on the outlet side of a refrigerant passage of the evaporator so as to be positioned in an air flow caused to flow by an air fan along heat transfer fins of the evaporator. As a result, the temperature of the air sensed by the chamber 30 can be made nearly equal to the temperature of the refrigerant coming to the outlet 23, and hence the flow rate of the high pressure refrigerant sent into the evaporator can be controlled accurately.

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 for a refrigeration cycle of an air conditioner for an automobile or the like.

[0002]

2. Description of the Related Art In an expansion valve, it is necessary to change the opening of the valve in accordance with the evaporation state of the refrigerant in the evaporator. Therefore, in a so-called gas-filled expansion valve, the tip of the temperature-sensing pipe in which the temperature-sensing refrigerant is sealed is brought into contact with the outlet side piping of the evaporator, and the base end side is communicated with the greenhouse-sensing greenhouse. A part of the airtight wall is formed by a diaphragm, and the diaphragm drives a valve element for changing the flow passage area of the throttle portion through which the high-pressure refrigerant before being sent to the evaporator passes.

[0003]

In such a gas-filled type expansion valve, it is necessary to surely bring the tip of the temperature sensitive tube into contact with the outlet side pipe of the evaporator in a wide area as much as possible. The cost of parts and the number of assembling steps for doing so were large, which pushed up the manufacturing cost.

Therefore, an object of the present invention is to provide an expansion valve capable of changing the opening degree of the valve in accordance with the evaporation state of the refrigerant in the evaporator with almost no increase in the cost of parts and the number of assembling steps. .

[0005]

In order to achieve the above-mentioned object, the expansion valve of the present invention has an evaporator in which a part of an airtight wall of a temperature-sensitive greenhouse in which a temperature-sensitive refrigerant is enclosed is formed by a diaphragm. In the expansion valve in which the valve body for changing the flow passage area of the throttle portion through which the high-pressure refrigerant passes before being sent is driven by the diaphragm, the heat transfer fin formed continuously with the refrigerant flow passage of the evaporator is formed. It is characterized in that the above-mentioned greenhouse is arranged at a refrigerant outlet portion of an air stream flowing along.

It should be noted that the greenhouse is preferably arranged near the refrigerant outlet of the refrigerant passage of the evaporator.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an evaporator 10 and an expansion valve 20 used in a refrigerating cycle of an automobile air conditioner or the like.

High-pressure refrigerant pipe 5 to which high-pressure refrigerant liquid is sent
The expansion valve 20 is connected to the tip of the valve 1, and the refrigerant passing through the expansion valve 20 is sent into the evaporator 10 while undergoing adiabatic expansion. Then, the refrigerant that has evaporated to a low pressure in the evaporator 10 is sent out through the low-pressure refrigerant pipe 52.

The refrigerant flow path 11 in the evaporator 10 is made of a metal material having good thermal conductivity, and the refrigerant sent from the expansion valve 20 is the evaporator 1 as shown in FIG.
In the right half part of 0, it is divided into a plurality of pipe lines and turns to the back side in a U shape, then is sent to the left half part to be divided into a plurality of pipe lines and is turned to the front side in a U shape to the low pressure refrigerant pipe 52. It is piped to be sent out.

Then, as shown in FIGS. 1 and 3,
The heat transfer fins 12 made of a metal plate having good thermal conductivity are provided in the gaps between the refrigerant flow paths 11 over substantially the entire length so as to come into contact with the refrigerant flow paths 11 arranged in a comb tooth shape.

FIG. 4 shows the expansion valve 20. 21 is
A high-pressure refrigerant inlet 22 to which the tip of a high-pressure refrigerant pipe 51 is connected and a refrigerant outlet 23 connected to the evaporator 10 are the main body blocks of the expansion valve 20 and are formed with their directions turned at right angles.

In the middle of the refrigerant passage between the high-pressure refrigerant inlet 22 and the refrigerant outlet 23, a throttle hole 24 having a narrowed passage cross-sectional area of the refrigerant is formed straight with respect to the refrigerant outlet 23. , A spherical valve element 25 for varying its flow passage area
Is arranged so as to face the throttle hole 24 from the refrigerant outlet 23 side. Reference numeral 26 is a compression coil spring for urging the valve body 25 in a direction to press it against the throttle hole 24, and 27 is a spring receiver.

A greenhouse 30 is formed at the end opposite to the refrigerant outlet 23 with the throttle hole 24 interposed therebetween, and it connects the back side portion of the diaphragm 31 and the refrigerant passage on the refrigerant outlet 23 side, which will be described later. The communication holes 29 communicate with each other.

A refrigerant such as R12, which becomes a saturated vapor under the operating conditions of the refrigeration cycle, is enclosed in the greenhouse 30. The refrigerant filling hole is sealed by the plug 39.

A heat-sensitive fin 38 formed of a metal material having good heat conductivity and formed in a reel shape is attached so as to come into contact with the outer surface of the greenhouse case 37 made of metal material having good heat conductivity.

The greenhouse 30 forms an airtight chamber, and a part of its wall surface is formed by a diaphragm 31 made of a flexible thin film. Therefore, the diaphragm 31
Is displaced by the pressure difference between the pressure in the greenhouse 30 and the pressure in the space on the back surface side of the diaphragm 31.

On the back surface side of the diaphragm 31, a disk-shaped diaphragm receiver 34 is arranged in contact with the diaphragm 31 with its center position aligned with the diaphragm 31, and sandwiched between the diaphragm receiver 34 and the valve body 25. Therefore, the rod 35 is arranged so as to be movable back and forth in the axial direction.

Reference numeral 33 denotes an O-ring for sealing that prevents the refrigerant from leaking along the outer peripheral surface portion of the rod 35, and 34 holds the O-ring 33 and presses the rod 35.
Is a tubular body that serves as an advancing and retreating guide.

In the expansion valve 20 thus constructed, the high-pressure refrigerant flowing from the high-pressure refrigerant inlet 22 to the refrigerant outlet 23 is sent to the evaporator 10 while undergoing adiabatic expansion by passing through the throttle hole 24. The valve body 25 is displaced according to the pressure in the greenhouse 30, and the flow rate of the high-pressure refrigerant changes.

Reference numeral 100 shown in FIG. 1 is a blower fan for applying an air flow for cooling to the evaporator 10. The greenhouse 30 is located in the left half of the evaporator 10 (that is, the outlet of the refrigerant passage 11). (Side portion), and is arranged close to the evaporator 10 at the outlet portion of the air flow that is made to flow along the heat transfer fins 12 of the evaporator 10 by the blower fan 100.

Therefore, the temperature of the air sensed by the greenhouse 30 is close to the temperature of the refrigerant at the position where it passes through the evaporator 10 and reaches the refrigerant outlet, and the diaphragm 31 is displaced corresponding to the temperature. The flow rate of the high-pressure refrigerant sent to the evaporator 10 is controlled.

Incidentally, as shown in FIG.
Alternatively, the heat-sensitive fins 38 may be removed so that the airflow directly impinges on the greenhouse case 37.

[0023]

According to the present invention, the temperature-sensing chamber is arranged at the outlet of the air flow that flows along the heat transfer fins that are formed in series with the refrigerant flow path of the evaporator, so that the refrigerant in the evaporator is It is possible to adjust the flow rate of high-pressure refrigerant according to the state of evaporation with a configuration that greatly reduces the cost of parts and the number of assembly steps.By placing a greenhouse in the vicinity of the outlet of the refrigerant flow path of the evaporator, The flow rate of the refrigerant can be controlled substantially corresponding to the temperature of the discharged refrigerant.

[Brief description of drawings]

FIG. 1 is a perspective view of an evaporator and an expansion valve according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a refrigerant flow path of the evaporator according to the first embodiment of the present invention.

FIG. 3 is a front cross-sectional view of a downstream portion of the air flow of the evaporator according to the first embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of the expansion valve according to the first embodiment of this invention.

FIG. 5 is a vertical sectional view of an expansion valve according to a second embodiment of the present invention.

[Explanation of symbols]

 10 Evaporator 11 Refrigerant flow path 12 Heat transfer fin 24 Throttle hole 25 Valve body 30 Greenhouse 31 Diaphragm

Claims (2)

[Claims] 1. A valve for forming a part of an airtight wall of a greenhouse in which a temperature-sensitive refrigerant is enclosed by a diaphragm to change a flow passage area of a throttle portion through which high-pressure refrigerant before being sent to an evaporator passes. In the expansion valve in which the body is driven by the diaphragm, the greenhouse is arranged at the outlet of the air flow that flows along the heat transfer fins formed in series with the refrigerant flow path of the evaporator. Expansion valve. 2. The expansion valve according to claim 1, wherein the greenhouse is disposed near a refrigerant outlet of a refrigerant passage of the evaporator.