JPH0979705A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: An expansion valve to be used in a freezing cycle is provided with a function to enlarge a degree of opening of the valve in an enforced manner. SOLUTION: An expansion valve 1 has a valve part 10 and a valve operating part 50 fixed to the valve part 10. A main body 11 of the valve has an inlet port 12 and an outlet port 13, and an operating rod 22 for a valve member 20 is inserted into an orifice 14. The valve member 20 is biased by an adjusting spring 26 toward a valve closing direction. The operating rod 22 is pressed by a diaphragm 62 through a stopper 60. Gas pressure for use in unifying pressure is fed into a lower pressure chamber of the diaphragm, and a gas pressure flowed from a thermo-sensitive cylinder 94 for the refrigerant is fed into a pressure chamber above the diaphragm so as to control a degree of opening of the valve. A spring 57 made of shape-memory alloy arranged at an upper part of the diaphragm is heated up to a set temperature when an electrical heater 80 is operated and then the spring is extended to make an enforced increasing of the degree of opening of the valve.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an expansion valve used in a refrigeration cycle or the like.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 6-21746 discloses
Disclosed is an expansion valve used in a vehicle air conditioner. This type of expansion valve is configured so that the valve body that controls the opening of the valve is operated by a diaphragm, and the gas pressure generated corresponding to the temperature of the refrigerant is introduced into the pressure chamber formed by the diaphragm to allow the valve to operate. It has the function of adjusting the opening. When the temperature of the refrigerant gas flowing during the refrigeration cycle of the air conditioner becomes high, the opening degree of the expansion valve is increased to increase the flow rate of the refrigerant,
Strengthen refrigeration capacity.

[0003]

In the conventional expansion valve, the opening degree of the valve is unitarily determined according to the temperature of the refrigerant, and the opening degree of the valve is arbitrarily increased when necessary for refrigeration. It had no mechanism to increase capacity. The present invention provides an expansion valve provided with means for arbitrarily increasing the valve opening degree when necessary.

[0004]

The expansion valve of the present invention is mounted on a valve body having an orifice connecting the inlet port and the outlet port of the refrigerant, an actuating rod penetrating the orifice, and a tip of the actuating rod. A valve body having an adjusting spring for urging the valve body toward the orifice, and a valve operating portion that is connected to the valve portion and operates the valve body via an operating rod. A diaphragm that presses the operating rod,
A pressure chamber formed by a diaphragm, into which a gas pressure corresponding to the temperature of the refrigerant is introduced, and a spring made of a shape memory alloy that expands when heated to a set temperature and urges the diaphragm in the valve opening direction. , An electric heater for heating a shape memory alloy spring.

[0005]

When the electric heater does not operate, it functions as an expansion valve that adjusts the opening of the valve according to the temperature of the refrigerant. When the electric heater is activated, the shape memory alloy spring expands and presses the diaphragm, forcing the valve to open and increasing the flow rate of the refrigerant.

[0006]

1 is an explanatory view showing the overall structure of an expansion valve of the present invention. The expansion valve, generally designated by reference numeral 1, includes a valve section 10 and a valve operating section 5 mounted on the valve section 10.
0. The valve unit 10 includes a valve body 11 and a valve body 11
A valve body 2 slidably inserted into the inside through an actuating rod 22.
Has zero. The valve body 11 has an inlet port 12 and an outlet port 13, and an orifice 14 is provided between both ports. The actuation rod 22 penetrates the orifice 14 and
The valve body 20 in contact with the lower end of 2 is brought into contact with or separated from the valve seat formed at the inlet of the orifice 14 to adjust the valve opening. The upper end of the operating rod 22 is in contact with the stopper 60. The valve body 20 is supported by the support member 24, and the support member 24 is biased by the adjusting spring 26 toward the valve body 20 toward the orifice 14. By adjusting the screwing amount of the hollow adjusting nut 28 screwed into the inlet port 12, the pressing force on the valve body 20 is adjusted. Brass is used for the valve body 11 and the stopper 60, and stainless steel is used for the operating rod 22.

The upper portion of the actuating rod 22 penetrates an opening provided in the valve body 11 and is sealed by an O-ring 15. A washer 16 is placed on top of the O-ring 15 and receives the end of the spring 18. The other end of the spring 18 abuts the collar 30 and pushes up the stopper 60 provided in the valve operating portion 50 via the actuating rod 22 penetrating the collar 30 press-fitted into the valve body 11. The passage 32 formed in the valve body 11 is connected to an O-ring pipe 35 fitted with an O-ring 37 via a capillary 34, and is connected to an outlet pipe of an evaporator (not shown) of a refrigeration system via a nut 36. Connected. The gas pressure in the outlet pipe of the evaporator is sent to the passage 32 of the valve body 11 via the capillary 34, and the valve operating unit 5
0 is fed into the first pressure chamber 64 of the diaphragm 62. The valve operating unit 50 is screwed onto the upper portion of the valve body 11.

2 is a sectional view of the valve operating portion 50, FIG. 3 is a top view, and FIG. 4 is a right side view. The valve operating unit 50 is the valve body 1
The structure is such that the diaphragm 62 is sandwiched by the casing 51 having a threaded portion that is screwed into 1 and the flange member 52, and welded by heli-arc welding W ₁ . Diaphragm 6
The lower part of 2 is supported by the stopper 60 and
The pressure chamber 64 is formed. A second pressure chamber 66 is formed in the upper portion of the diaphragm 62. A cap 55 is fixed to the upper portion of the flange member 52 by silver brazing W ₂ and the ring member 5 is attached to the outer periphery of the flange member 52.
4 is welded.

The cap 55 is made of a material having good thermal conductivity such as a copper alloy, and has a coil spring 57 made of a shape memory alloy (for example, Furukawa NT alloy manufactured by Furukawa Electric Co., Ltd.) inside.
Is inserted. The coil spring 57 made of shape memory alloy has a function of expanding when heated to a set temperature and generating a spring force. The lower end of the coil spring 57 is supported by a resin spring receiving member 58, and the spring receiving member 58 is placed on the upper surface of the diaphragm 62. A resin case 70 is attached to the ring member 54 with screws 72. At that time, the packing 59 is sandwiched between the cap 55 and the case 70 to keep waterproof. An electric heater (for example, a product name PTC thermistor heating element manufactured by TDK Corporation) 80 is arranged in the case 70, and electrode terminals 82 and 84 for power supply are in contact with both surfaces of the electric heater 80. A resin cover 74 is fixed to the upper portion of the case 70 by screws 76.

As shown in FIGS. 3 and 4, two electrodes 8 are provided.
2, 84 are sandwiched and fixed by the case 70 and the cover 74. The first electrode 82 has a curved contact portion 82a, and the curved contact portion 82a contacts the electric heater 80 to ensure electrical contact by utilizing elasticity. Second electrode 8
4 has a disk-shaped contact portion 84a, and contacts the disk-shaped electric heater 80. The second electrode 84 is an insulating sheet 85.
It is placed on the top of the metal cap 55 through the.

When electricity is supplied to the electric heater 80 through the electrodes 82 and 84, the electric heater 80 generates heat, and this heat heats the shape memory alloy spring 57 in the cap 55. The heated spring 57 expands and presses the diaphragm 62 through the spring receiver 58 and the actuating rod 22 side through the stopper 60.

On the other hand, the mounting member 9 is attached to the resin case 70.
The end portion of the capillary 90 inserted by 2 penetrates the cap 55, is welded to the cap 55, and is communicated with the second pressure chamber 66. A temperature sensitive cylinder 94 is attached to the other end of the capillary 90, and the temperature sensitive cylinder senses the temperature of the refrigerant gas at the evaporator outlet and adjusts the gas pressure in the cylinder. Temperature sensitive tube 94
The gas pressure inside is the second pressure chamber 6 above the diaphragm 62.
Introduced into the cylinder 6, the diaphragm 62 is deformed to adjust the opening of the valve.

As described above, in the expansion valve of the present invention, when the electric heater is not operated, as in the conventional expansion valve, the evaporator outlet of the evaporator introduced into the pressure chamber on the valve operation rod side of the diaphragm is introduced. The pressure of the gas refrigerant and the gas generated by sensing the refrigerant temperature at the evaporator outlet are introduced into the pressure chamber above the diaphragm, and the opening of the expansion valve is adjusted to a position where the generated gas pressure is balanced. The flow rate of the refrigerant passing through the expansion valve is controlled. When the electric heater is energized, the shape memory alloy spring is heated by the generated heat, and the spring expands at a set temperature. Due to this action, the opening degree of the valve becomes larger. Therefore, a larger amount of refrigerant can pass through the expansion valve to enhance the refrigerating capacity.

In the above description, the case where a capillary tube is used as the expansion valve has been described, but it goes without saying that the present invention can be applied to other expansion valves, for example, a temperature expansion valve having a structure not using a capillary tube. That is, FIG. 5 is a vertical cross-sectional view showing the structure of an embodiment of the present invention showing the expansion valve, and FIG. 6 is a side view showing the overall external structure of the side surface of FIG. 5 viewed from the direction of arrow A. . In FIG. 6, reference numeral 100 is a through hole for a bolt for attaching the expansion valve. This expansion valve includes a valve body 130 that constitutes the valve unit 110.
And an operation control unit 50 disposed in the valve unit 110. The valve portion 110 has a substantially rectangular outer shape, and the lower portion 120 is stolen to be thin. The structure of the valve body 130 described below is well known, and FIG. 5 shows an expansion valve in which the operation control unit of FIG. 2 is arranged in a well-known valve portion in the same manner as in FIG.

In the valve section 110, there is a first passage 132 interposed between the refrigerant outlet of the condenser 255 constituting the refrigeration cycle and the receiver 256 through the receiver 256 to the refrigerant inlet of the evaporator 258, and the refrigerant outlet of the evaporator 258. To a refrigerant inlet of the compressor 254, a second passage 134 interposed between the second passage 134 and the compressor 254 is formed vertically apart from each other.

A valve hole 132a for adiabatically expanding the liquid refrigerant supplied from the refrigerant outlet of the receiver 256 is formed in the first passage 132. A valve seat is formed at the inlet of the valve hole 132a, and the valve body 132b is biased on the valve seat by a biasing means 132c such as a compression coil spring. The first passage 132 into which the liquid refrigerant from the receiver 256 is introduced serves as a passage for the liquid refrigerant, and is connected to the inlet port 131,
It has a valve chamber 135 continuous with the inlet port 131.
The valve chamber 135 is a bottomed chamber formed coaxially with the valve hole 132 a, and is closed by a plug 137.

An operation control unit 50 for driving the valve body 132b is mounted on the upper end of the valve unit 110. The configuration of the operation control unit 50 is the same as that of the operation control unit 50 shown in FIGS. 1 and 2, and the same reference numerals indicate the same parts. In the operation control unit 50, the flange member 212 is attached to the upper end of the valve unit 110 by screwing through the packing 170. Refrigerant gas is enclosed in the cap 55 that constitutes the operation control unit 50, and the tube 90 for enclosing the refrigerant gas is completely sealed after the refrigerant gas is enclosed. The enclosed refrigerant gas is sent to the gas chamber 66 above the diaphragm 62. The pressure in the second passage 134 is transmitted to the gas chamber 64 below the diaphragm 62.

The evaporator 25 is provided in the second passage 134.
8, the refrigerant vapor flows from the refrigerant outlet, the passage 134 serves as a vapor-phase refrigerant passage, and the pressure of the refrigerant vapor is equalized by the pressure equalizing holes 136.
The pressure is applied to the lower pressure working chamber 136c via e. The lower pressure working chamber 136c communicates with the second passage 134 via a pressure equalizing hole 136e formed concentrically with respect to the center line of the valve hole 132a.

A valve body drive rod 136f extending from the lower surface of the diaphragm 62 to the valve hole 132a of the first passage 132 is concentrically arranged in the pressure equalizing hole 136e. The valve body drive rod 136f forms a stopper 60 at its upper end, contacts the operating rod 140 at its lower end, and contacts the valve body 132b at the lower end of the operating rod 140. Valve drive rod 136f
Is the inner surface of the pressure working chamber 136c and the second passage 134.
It is slidably supported in the vertical direction by a partition wall between the first passage 132 and the first passage 132, and the lower end is in contact with the valve body 132b. A packing for preventing refrigerant leakage between the first passage 132 and the second passage 134 is provided in a region of the outer peripheral surface of the valve body drive rod 136f corresponding to the sliding guide hole of the valve body drive rod in the partition wall. 136g is provided. The valve body 130, the valve body drive rod 136f, and the stopper 60 are made of aluminum alloy, and the diaphragm 62 is made of stainless steel.

The cap 55 of the operation control unit 50 is filled with a refrigerant gas and is exposed to the second passage 134 and the pressure equalizing hole 136e communicating with the second passage 134 and exposed to the valve disc drive rod. Second through 136f and diaphragm 62
The heat of the refrigerant vapor from the refrigerant outlet of the evaporator 258 flowing through the passage 134 of
It will operate as a temperature sensing unit. Therefore, the pressure corresponding to the heat transferred to the refrigerant gas in the temperature sensing portion is applied to the upper surface of the diaphragm 62, and the diaphragm 62 is the difference between the pressure of the gas applied to the upper surface and the pressure applied to the lower surface of the diaphragm. It is displaced up and down by. This displacement is transmitted to the valve body 132b via the valve body drive rod 136f and is transmitted to the valve body 1b.
32b is moved toward or away from the valve seat of the valve hole 132a, and as a result, the refrigerant flow rate is controlled.

The electrodes 82, 84 of the operation control unit 50 are
When electric power is supplied to the electric heater 80 through the electric heater 80, the electric heater 80, which is a heating element, generates heat, and this heat heats the shape memory alloy spring 57 in the cap 55. The heated spring 57 extends and presses the diaphragm 62 through the spring receiver 58 and the valve drive rod 136f side through the stopper 60.
Therefore, when the electric heater is not heated,
Like the conventional expansion valve, the gas chamber 6 above the diaphragm
Due to the difference between the gas pressure of 6 and the pressure of the gas chamber 64 below the diaphragm, the diaphragm is displaced up and down and the valve hole 13
The opening of 2a is adjusted to control the flow rate of the passing refrigerant.

When electric power is supplied to the electric heater, the heat generated heats the spring made of the shape memory alloy, and the spring at the installation temperature expands. Due to this action, the valve opening becomes larger as shown in FIG. Therefore, a larger amount of the refrigerant passes through the expansion valve, and the refrigerating capacity can be enhanced.

[0023]

INDUSTRIAL APPLICABILITY As described above, the present invention relates to an expansion valve used in a refrigeration system. The expansion valve is made of a shape memory alloy that expands when heated by an electric heater and urges the valve in the opening direction. And a spring. When it is necessary to increase the flow rate of the refrigerant passing through the expansion valve, the electric heater is energized to increase the opening degree of the valve. The opening / closing action of the valve by the spring made of shape memory alloy is slower than the opening / closing action by the solenoid valve or the like. Therefore, a sudden change in the refrigerant gas pressure can be avoided, and damage to equipment such as the diaphragm can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the configuration of an embodiment of an expansion valve of the present invention.

FIG. 2 is a sectional view of a valve operating portion.

FIG. 3 is a top view of a valve operating portion.

FIG. 4 is a right side view of the valve operating portion.

FIG. 5 is an explanatory diagram showing the configuration of another embodiment of the expansion valve of the present invention.

6 is a side view of the expansion valve shown in FIG.

[Explanation of symbols]

 1 Expansion valve 10 Valve part 11 Valve body 12 Inlet port 13 Outlet port 14 Orifice 20 Valve body 22 Actuating rod 26 Adjusting spring 30 Collar 50 Valve operating part 51 Casing 54 Ring member 55 Cap 57 Shape memory alloy spring 58 Spring receiving member 60 Stopper 70 Case 74 Cover 80 Electric Heater 82, 84 Electrode Terminal 90 Capillary 94 Thermosensitive Tube

Claims (1)

[Claims] 1. A valve body having an orifice for connecting both the inlet port and the outlet port of the refrigerant, an operating rod penetrating the orifice, a valve body attached to the tip of the operating rod, and a valve body facing the orifice. A valve unit having an adjusting spring that biases the valve unit, and a valve operating unit that is connected to the valve unit and operates the valve body through the operating rod. The valve operating unit is formed by a diaphragm that presses the operating rod and a diaphragm. And a pressure chamber into which a gas pressure corresponding to the temperature of the refrigerant is introduced, a spring made of a shape memory alloy that expands when heated to a set temperature and urges the diaphragm in the valve opening direction, and a shape memory An expansion valve comprising an electric heater for heating an alloy spring.