JP2586427B2 - Expansion valve for refrigeration cycle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an expansion valve for a refrigeration cycle, and is suitable for use in, for example, a car air conditioner.

(Prior Art) FIG. 3 shows a vertical sectional view of a conventional expansion valve 100 for a refrigeration cycle.
3, shown as connected in a refrigeration cycle including a condenser 14, a receiver 15, and an evaporator 12. The expansion valve 100 has a first flow path 10 for receiving the high-pressure liquid refrigerant from the receiver 15 and a first flow path via an expansion orifice 16.
10 through which the refrigerant flows toward the evaporator 12
And the flow path 11 of FIG. The expansion orifice 16 is a temperature-sensitive stick 4
The valve body 9 is controlled by the size of the gap between the spherical valve element 9 attached to the lower end of the rod-shaped member 8 connected to the lower end of the valve member and the valve seat 16a. 3, it is pressed upward in FIG. The expansion valve 100
Further, a third receiving the low-pressure refrigerant from the evaporator 12
And a fourth flow path 19 for sending the low-pressure refrigerant toward the compressor 13. The first flow path 10, the expansion orifice 16 and the second flow path 11 constitute a high-pressure refrigerant flow path,
The third flow path 18 and the fourth flow path 19 constitute the low-pressure refrigerant flow path 5. The expansion valve 100 further has a temperature-sensitive chamber 22 defined by a lid 23 made of a SUS material in the shape of a shade and the diaphragm 1 and filled with a temperature-sensitive gas such as R12. A stop 3 made of a material having good heat conductivity is connected to the lower surface of the diaphragm 1, and the upper end of a temperature sensing rod 4 is loosely inserted into and connected to the recess of the stop 3, and crosses the low-pressure refrigerant flow path 5. And transmits the temperature of the refrigerant flowing through the low-pressure refrigerant flow path 5 to the temperature-sensitive gas in the temperature-sensitive chamber 22 through the stopper 3. Below the stopper 3, there is a chamber 21 which communicates with an outer equalization pipe (not shown) through an opening 20, and the stopper 3 is capable of performing a limited vertical movement in this chamber 21. Also, Stopper 3
The temperature sensing rod 4 slidably extends in the peripheral wall 24 of the valve body between the diaphragm 1 and the low-pressure refrigerant flow path 5 and extends across the low-pressure refrigerant flow path 5. An O-ring 6 is fitted to the temperature sensing rod 4 to seal between the temperature sensing rod 4 and the surrounding wall 24. Therefore, the temperature-sensitive rod 4 transmits the temperature of the refrigerant flowing through the low-pressure refrigerant flow path 5 to the temperature-sensitive gas in the temperature-sensitive chamber 22, the pressure of the temperature-sensitive gas, the force of the spring 17, Room 21
The gap between the spherical valve body 9 and the valve seat 16a is slid up and down to a position determined depending on the internal pressure, thereby controlling the size of the expansion orifice 16 through which the high-pressure refrigerant passes. It comes to adjust.

An expansion valve for a refrigeration cycle having substantially the same configuration as that described above is disclosed in JP-A-63-29166, U.S. Pat.
No. 5,037,645 and U.S. Pat. No. 3,537,645.

(Problems to be Solved by the Invention) As described above, in the conventional expansion valve for a refrigeration cycle, the temperature of the refrigerant flowing out of the evaporator is transmitted to the temperature-sensitive gas through the temperature-sensitive rod, and the temperature of the temperature-sensitive gas changes. Therefore, the flow rate of the refrigerant to the evaporator is adjusted by displacing the valve body.However, since the expansion valve for the refrigeration cycle is usually installed on the windward side of the evaporator, the expansion valve for the refrigeration cycle is not used. The main body, especially the upper part of the main body, is heated by warm air. For this reason, the temperature of the temperature-sensitive gas in the temperature-sensitive chamber becomes higher than the temperature of the low-pressure refrigerant, and particularly when the ambient temperature is high, the expansion valve may malfunction. .

An object of the present invention is to solve such a problem in a conventional expansion valve for a refrigeration cycle.

(Means for Solving the Problem) The present invention provides a high-pressure refrigerant flow path through which a refrigerant passes through an expansion orifice to an evaporator, a low-pressure refrigerant flow path through which a refrigerant discharged from the evaporator flows to a compressor, and a diaphragm. A temperature-sensitive chamber that is defined and encloses a temperature-sensitive gas, and one end of which is connected to the diaphragm in heat transfer relation to transmit the temperature of the refrigerant flowing through the low-pressure refrigerant flow path to the temperature-sensitive gas. A temperature sensing rod having a valve body for controlling an opening degree of the expansion orifice at the other end and extending between the low pressure refrigerant flow path, and located between the diaphragm and the low pressure refrigerant flow path; A refrigerating cycle expansion valve having a through hole for slidably receiving a temperature sensing rod and a peripheral wall of a valve body, wherein a resin ring is attached to the through hole and the inside of the resin ring is sensed. Warm The rod is configured to slide.

Further, the present invention is characterized in that the resin ring has a through-hole including a tapered hole whose diameter increases toward the low-pressure refrigerant flow path.

(Action) According to the present invention, since the resin ring acts to substantially block the heat transmitted from the peripheral wall of the valve body to the temperature sensing rod, the temperature sensitive gas is generated by the refrigerant flowing through the low pressure refrigerant flow path. The temperature is more accurately sensed. According to the present invention,
Since the through-hole of the resin ring includes a tapered hole whose diameter increases toward the low-pressure refrigerant flow path, the refrigerant flowing through the low-pressure refrigerant flow path travels closer to the diaphragm by transmitting through the temperature-sensitive rod, and the temperature-sensitive gas flows therethrough. The temperature of the refrigerant flowing through the low-pressure refrigerant flow path can be more accurately sensed.

Hereinafter, an embodiment of an expansion valve for a refrigeration cycle of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an expansion valve for a refrigeration cycle according to an embodiment of the present invention, which is shown in a state connected to the inside of the refrigeration cycle as in FIG. FIG. 2 (a),
(B) and (c) are a top view, a longitudinal sectional view, and a bottom view, respectively, of the resin ring used in the embodiment of the present invention.

In FIG. 1, the same reference numerals as those in FIG. 3 indicate the same or equivalent parts, and therefore detailed description is omitted. However, if the parts related to the present invention are repeated and explained, the present invention will be described. One embodiment of a refrigeration cycle expansion valve 20
0 is a high-pressure refrigerant flow path composed of the first flow path 10, the expansion orifice 16 and the second flow path 11 for allowing the refrigerant to pass through the expansion orifice 16 to the evaporator 12, and is discharged from the evaporator 12. It has a low-pressure refrigerant flow path 5 composed of a third flow path 18 and a fourth flow path 19 for flowing the refrigerant to the compressor 13. Also, the diaphragm 1 and, for example, SUS
A temperature sensing chamber 22 defined by a lid 23 made of a material is provided, and the temperature sensing chamber 22 is filled with a temperature sensing gas such as R12 gas. A stop 3 made of a material having good heat conductivity, for example, brass, is connected to the lower surface of the diaphragm 1, and the stop 3 can move up and down within the chamber 21 with a limited amount. The upper end of the temperature sensing rod 4 is loosely fitted into a recess provided on the lower surface of the stopper 3, and is connected to the stopper 3 so as to absorb misalignment. The temperature sensing rod transmits the temperature of the refrigerant flowing through the low-pressure refrigerant flow path 5 to the temperature sensing gas in the temperature sensing chamber 22 via the stopper 3 and the diaphragm 1.
A spherical valve element 9 is attached to the lower end of the temperature sensing rod 4 via a rod-shaped member 8, and the valve element 9 controls the opening degree of the expansion orifice 16 in cooperation with the valve seat 16a. Between the diaphragm 1 and the low-pressure refrigerant flow path 5, there is provided a peripheral wall 24 of a valve body forming a through-hole 2 through which a temperature-sensitive rod 4 extending across the low-pressure refrigerant flow path 5 is vertically movable. I have.

In the present invention, the resin ring 7 is mounted in the through hole 2 defined in the peripheral wall 24 of the valve body. In this embodiment, the resin ring 7 has a cylindrical outer surface, is made of Teflon, and has a thermal conductivity of 0.24 to 0.36 W / m · k. In the resin ring 7, as shown in FIG. 2, a cylindrical hole 7b opened at one end thereof and a ring 7b connected to the hole 7b.
And a tapered hole 7a which is open at the other end thereof to form a through hole. The mounting method is performed by driving and fitting the resin ring 7 into the through hole 2.

An O-ring 6 is mounted in a circumferential groove formed on the peripheral surface of the temperature sensing rod 4, and a cylindrical hole of the resin ring 7 is provided together with the temperature sensing rod 4.
7b can be slid up and down, and the low-pressure refrigerant flow path 5
The chamber 21 is hermetically sealed. As can be seen from FIG. 1, the tapered hole 7a acts to make the refrigerant in the low-pressure refrigerant flow path 5 closer to the diaphragm 1 and thus improves the sensitivity of the temperature sensing chamber 22.

Next, the operation of the above embodiment of the present invention will be described.

The refrigerant compressed by the compressor 13 and condensed by the condenser 14 is separated into a gas-liquid two phase in the receiver 15 and
Is discharged through the expansion orifice 16 of the expansion valve 200, where the liquid refrigerant is adiabatically expanded and the evaporator 12
And evaporates in the evaporator 12 to remove heat from around the evaporator 12 to become a high-temperature, low-pressure refrigerant. This low-pressure refrigerant is returned to the compressor 13 through the low-pressure refrigerant flow path 5 of the expansion valve 200. Since this expansion valve 200 is located on the windward side of the evaporator 12, the ambient temperature is about 60 ° C. to 50 ° C. in the initial stage of the cool down, and about 27 ° C. during the steady operation.
It is about. This temperature is approximately 20 to less than the low pressure refrigerant temperature.
It is about 30 ° C higher. Accordingly, the temperature of the peripheral wall 24 of the main body of the expansion valve 200 rises remarkably, and the temperature of the peripheral wall 24 causes disturbance to the temperature of the low-pressure refrigerant to be transmitted by the temperature sensing rod 4. However, in the present invention, since the above-described resin ring 7 is interposed between the peripheral wall 24 and the temperature-sensitive rod 4, heat transfer from the peripheral wall 24 to the temperature-sensitive rod 4 is performed. Is shut off. Thus, the degree to which the temperature sensing rod 4 is affected by the ambient temperature is reduced, and the temperature sensing rod 4 makes the temperature of the low pressure refrigerant more sensitive to the temperature sensing gas in the temperature sensing chamber 22. As described above with reference to FIG. 2, the resin ring 7 is provided with the tapered hole 7a having a large diameter toward the low-pressure refrigerant flow path, so that the low-pressure refrigerant is supplied to the lower part of the diaphragm 1. Since the temperature can be approached, the temperature of the low-pressure refrigerant can be more accurately transmitted to the temperature-sensitive gas.

(Effects of the Present Invention) According to the present invention, the influence of the ambient temperature on the temperature sensing rod of the expansion valve can be reduced, so that the opening degree of the expansion orifice is controlled more accurately depending on the temperature of the low-pressure refrigerant. be able to. Further, by configuring the through hole of the resin ring to be a tapered hole whose diameter increases toward the low-pressure refrigerant flow path, the low-pressure refrigerant comes closer to the diaphragm, and the low-pressure refrigerant and the temperature-sensitive gas communicate with each other. The temperature difference is reduced, and the possibility of malfunction is further reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of an expansion valve for a refrigeration cycle of the present invention, shown in a state connected in a refrigeration cycle.
(A), (b) and (c) of the figure are a top view, a longitudinal sectional view and a bottom view of an example of a resin ring 7 used in the present invention, respectively, and FIG. It is a longitudinal sectional view of a conventional refrigeration cycle expansion valve. DESCRIPTION OF SYMBOLS 1 ... Diaphragm, 2 ... Passage, 3 ... Stopper, 4 ... Temperature sensing rod, 5 ... Low pressure refrigerant flow path, 6 ... O-ring, 7 ... Resin ring, 7a, 7b ... Hole, 8 ... rod-shaped member, 9 ... valve element, 10 ... first flow path, 11 ... second flow path, 12 ... evaporator, 13 ... compressor, 14 ... condenser, 15 ... receiver, 16 ... expansion orifice, 16a ... valve seat, 17 ... spring, 18 ... third flow path, 19 ... fourth flow path, 20 ... opening, 21 ... chamber, 22 ... thermosensitive chamber, 23 ... lid, 24 ... wall around valve body, 200 ... expansion valve for refrigeration cycle.

Claims (2)

(57) [Claims] A temperature-sensitive diaphragm defined by a diaphragm, a high-pressure refrigerant passage for passing refrigerant through an expansion orifice to an evaporator, a low-pressure refrigerant passage for flowing refrigerant discharged from the evaporator to a compressor, and a diaphragm. A temperature sensing chamber enclosing a gas, one end of which is connected to the diaphragm in heat transfer relationship to transmit the temperature of the refrigerant flowing through the low pressure refrigerant flow path to the temperature sensitive gas and traverse the low pressure refrigerant flow path; A temperature-sensitive rod provided with a valve body for controlling the opening of the expansion orifice at the other end, and located between the diaphragm and the low-pressure refrigerant flow path, so that the temperature-sensitive rod is slidable. A refrigerating cycle expansion valve having a valve body surrounding wall defining a through hole for receiving, wherein a resin ring is attached to the through hole so that the temperature sensing rod slides in the resin ring. Composed Refrigeration cycle for the expansion valve, wherein the door. 2. The refrigeration cycle expansion valve according to claim 1, wherein said resin ring has a through-hole including a tapered hole having a large diameter toward said low-pressure refrigerant flow path.