JPH05118467A - Expansion valve - Google Patents

Abstract

PURPOSE:To provide an expansion valve free from the effect of outside air temperature and capable of displaying proper function at all times. CONSTITUTION:A synthetic resin cover 19 of high insulation quality is screwed and fixed above a low pressure coolant passage 17 in an expansion valve body 6, and a bellows 22 is laid within the cover 19. This bellows 22 internally seals pressure response gas. The temperature of a low pressure coolant released from an evaporator 5 is transferred to the bellows 22, thereby adjusting the opening of an expansion orifice 8. The bellows 22 is housed in the expansion valve body 6 and concealed with the cover 19. According to this construction, the bellows 22 becomes free from the effect of outside air temperature, and operates in response only to the temperature of the coolant.

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 a car air conditioner.

[0002]

2. Description of the Related Art This type of expansion valve has an orifice for converting a liquid refrigerant from a compressor side into a gas-liquid two-phase refrigerant, and sends the gas-liquid two-phase refrigerant to an evaporator side. In this case, the expansion valve is provided with an adjusting mechanism for adjusting the opening degree of the orifice according to the cooling load.
Then, conventionally, as the adjusting mechanism, a diaphragm chamber as a greenhouse is provided in the expansion valve main body. Then, the refrigerant temperature on the outlet side of the evaporator is transmitted to the diaphragm chamber to expand the enclosed gas in the diaphragm chamber.
The diaphragm is deformed in response to the contraction, and the opening of the orifice is adjusted according to the deformation amount. That is, when the refrigerant temperature is high and the load is high, the pressure in the diaphragm chamber is increased, the opening degree of the orifice is increased, and the refrigerant supply amount to the evaporator is increased. Further, when the refrigerant temperature is low and the load is low, the pressure in the diaphragm chamber becomes low, the orifice opening becomes small, and the refrigerant supply amount is reduced.

[0003]

A diaphragm having a large diameter is required in order to obtain the optimum operation amount necessary for adjusting the orifice opening, that is, a sufficient deformation amount of the diaphragm. Therefore, the conventional expansion valve
A large diameter diaphragm chamber will be installed. Therefore, in the conventional expansion valve, not only does the diaphragm chamber largely protrude from the expansion valve main body, but the size of the entire expansion valve is increased, and the diaphragm chamber is exposed to the external atmosphere, so that the temperature inside the diaphragm chamber is kept outside. It will be affected by the temperature. Therefore, when the outside temperature is high, the temperature inside the diaphragm chamber becomes unnecessarily high, and the orifice opens due to the outside temperature to supply more refrigerant than necessary, causing a problem that superheat cannot be taken. .. On the other hand, when the outside air temperature is low, on the contrary, the temperature inside the diaphragm chamber is lowered, and in the worst case, the orifice is closed and the refrigerant supply is stopped (cooling).

It is an object of the present invention to provide an expansion valve having a structure which can be downsized as a whole and which is not affected by the outside air temperature.

[0005]

The expansion valve of the present invention has a first structure.
In the invention, in the expansion valve main body, a liquid refrigerant passage communicating with the condenser and introducing the refrigerant condensed by the condenser is communicated with the liquid refrigerant passage through an expansion orifice, and Atomized refrigerant passage for supplying the refrigerant adiabatically expanded to the evaporator, a low pressure refrigerant passage into which the refrigerant passing through the evaporator is introduced, a valve body for adjusting the opening / closing amount of the expansion orifice, and the low pressure refrigerant passage A part of the temperature sensing member, a bellows which is filled with an inert gas and expands and contracts due to a temperature change transmitted from the temperature sensing member in contact with the temperature sensing member, and the bellows. And a transmission mechanism interposed between the valve body and the expansion / contraction operation of the bellows to the valve body as an opening / closing amount adjusting operation.

In the second invention, the bellows in the expansion valve of the first invention is covered with a cover made of synthetic resin fixed to the expansion valve body.

[0007]

Therefore, in the first aspect of the invention, since the entire bellows expands and contracts in the axial direction according to the temperature change, the operation amount can be increased, and the bellows may have a small diameter. Therefore, the bellows can be housed inside the expansion valve body without protruding to the outside, the overall size can be reduced, and the outside temperature is hardly affected.

Further, in the second aspect of the invention, since the cover blocks the bellows from the outside air, the influence from the outside air temperature can be cut off more surely.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an expansion valve for a car air conditioner will be described below with reference to the drawings.

FIG. 1 is a diagram showing an outline of a car air conditioner of the embodiment. The car air conditioner includes a variable capacity compressor 1, a condenser 2, a receiver 3, a box-type expansion valve 4 and an evaporator 5. In the box-type expansion valve 4, a valve chamber 7 is formed below the expansion valve body 6, and a liquid refrigerant passage 9 is formed slightly above the valve chamber 7 so as to communicate with the valve chamber 7 through an expansion orifice 8. There is. Further, a mist-like refrigerant passage 10 is formed on the side of the valve chamber 7 of the main body 6. A valve seat 11 is formed on the valve chamber 7 side of the expansion orifice 8.

An adjusting screw 14 also serving as a cap is screwed into the valve chamber 7 from below, and a coil spring 15 is mounted on the adjusting screw 14. The spring seat 13 is supported on the upper end of the coil spring 15. A spherical valve body 12 is welded on the spring seat 13 so as to correspond to the valve seat 11. Therefore, the valve body 12 is biased toward the valve seat 11 by the biasing force of the coil spring 15, and the biasing force is changed when the position of the coil spring 15 is changed by the adjusting screw 14. An O-ring 16 is provided on the adjusting screw 14 to keep the valve chamber 7 airtight.

Further, the passages 9 and 1 in the expansion valve body 6 are
A low-pressure refrigerant passage 17 is formed at a position above 0. One end of the low-pressure refrigerant passage 17 is connected to the compressor 1 driven by the vehicle engine, and the compressor 1 is connected to the liquid refrigerant passage 9 via the condenser 2 and the receiver 3. The atomized refrigerant passage 10 is connected to the evaporator 5 in the vehicle compartment.
Is connected to the other end of the low-pressure refrigerant passage 17.

On the other hand, a housing hole 18 having a screw is formed in the upper portion of the expansion valve body 6, and a synthetic resin cover 19 is screwed into the housing hole 18 via a packing 20 while keeping airtightness. It fits. The cover 19 is the housing chamber 2
1, a bellows 22 made of a metal such as copper, which constitutes a greenhouse and is filled with a gas having a pressure response in advance, is disposed in the housing chamber 21.
The bellows 22 changes the expansion / contraction amount according to the internal pressure and the differential pressure between the internal pressures. The bellows 22 contains activated carbon particles, and the inert gas is adsorbed by the activated carbon at low temperature.

The bottom of the accommodation hole 18 is a plunger hole 23.
It communicates with the low-pressure refrigerant passage 17 via a. or,
On the lower side of the low-pressure refrigerant passage 17, another plunger hole 23b is formed in the body 6 so as to face the plunger hole 23a.
Are formed. Further, a rod hole 24 having a smaller diameter is continuously formed below the plunger hole 23b, and the rod hole 24 communicates with the liquid refrigerant passage 9. An aluminum temperature sensing rod 25 is vertically movably fitted in the plunger hole 23b, and its upper end passes through the low pressure refrigerant passage 17 and is loosely fitted in the plunger hole 23a. A head portion 25a is formed at the upper end of the temperature sensitive rod 25, and the head portion 25a is in contact with the lower surface of the bellows 22. The low-pressure refrigerant passage 1
The 7 and the refrigerant passages 9 and 10 are kept in a sealed state (airtightness) by an O-ring 26 attached to the temperature sensitive rod 25.

An operating rod 27 made of stainless steel is provided in the rod hole 24 so as to be movable up and down.
Has an upper end abutting the temperature sensitive rod 25, an intermediate portion exposed in the liquid refrigerant passage 9, and a lower end abutting the valve body 12 in the expansion orifice 10. Therefore, the temperature sensitive rod 2
5 is pressed against the lower surface of the bellows 22 by the urging force of the coil spring 15 via the valve body 12 and the actuation rod 27. The bellows 22 is sandwiched between the head portion 25a and the inner bottom surface of the cover 19, and is not in contact with the peripheral wall of the cover 19 or the main body 6. Also, as the bellows 22 expands and contracts, the temperature sensitive rod 2
5, the valve body 12 moves up and down via the operating rod 27, and the temperature sensing rod 25 and the operating rod 27 constitute a transmission mechanism between the bellows 22 and the valve body 12.

Next, the operation of the expansion valve 4 thus constructed will be described. The highly compressed refrigerant discharged from the compressor 1 is condensed by the condenser 2, reaches the liquid refrigerant passage 9 of the receiver 3 and the expansion valve 4, and is adiabatically expanded by the expansion orifice 8 to become a gas-liquid two-phase refrigerant to be a valve chamber. Introduced in 7. Further, this refrigerant is introduced from the inside of the valve chamber 7 through the atomized refrigerant passage 10 into the evaporator 5 and vaporized to become a gas refrigerant. At this time, the evaporator 5 is cooled and the vehicle compartment is cooled. Further, the gas refrigerant discharged from the evaporator 5 passes through the low pressure refrigerant passage 17 and returns to the compressor 1 again.

On the other hand, the temperature sensitive rod 25 includes the spring seat 13 and the valve body 12.
Further, the compression coil spring 15 is always urged upward through the actuating rod 27 and pressed against the lower surface of the bellows 22. Therefore, the position of the valve body 12 with respect to the valve seat 11 (the opening degree of the expansion orifice 8) is a position where the biasing force of the compression coil spring 15 and the refrigerant pressure in the housing chamber 21 and the gas pressure in the bellows portion 22 are balanced. Kept in. The refrigerant pressure inside the housing chamber 21 is the evaporation pressure of the evaporator 5.

The temperature sensitive rod 2 is placed in the low pressure refrigerant passage 17.
Since part of No. 5 is exposed, the heat of the gas refrigerant passing through the low-pressure refrigerant passage 17 is transferred to the bellows 22 via the temperature sensitive rod 25 made of aluminum having a high thermal conductivity, and the heat inside the bellows 22 is lost. The active gas is expanded and contracted. Therefore, the expansion and contraction of the bellows 22 follows the temperature of the refrigerant on the outlet side of the evaporator 5.

That is, when the temperature inside the passenger compartment rises and the temperature of the refrigerant flowing into the low pressure refrigerant passage 17 also rises, the temperature sensitive rod 2
5, bellows 2 which has received heat transfer through the housing chamber 21
The inert gas 2 expands and the bellows 22 expands. This extension is transmitted to the temperature sensitive rod 25 and the actuation rod 27, and the opening degree of the expansion orifice 8 increases, so that the amount of the refrigerant flowing toward the inlet of the evaporator 5 increases.

Further, the temperature inside the passenger compartment decreases, and the low pressure refrigerant passage 1
When the temperature of the refrigerant passing through 7 also decreases, the gas pressure of the bellows 22 also decreases, and the valve body 12, the operating rod 27 and the temperature sensitive rod 25 move upward by the urging force of the coil spring 15 by the amount of contraction of the bellows 22 and expand. The opening degree of the orifice 8 is reduced, and the amount of the refrigerant toward the inlet of the evaporator 5 is reduced.

In this way, the opening of the expansion orifice 8 is adjusted according to the expansion and contraction amount of the bellows 22 depending on the cooling load, and the amount of refrigerant supplied to the evaporator 5 is adjusted.

In this case, in this expansion valve, the entire bellows 22 expands and contracts in the axial direction thereof as the refrigerant temperature changes. Therefore, even if the bellows 22 has a small diameter and a small size, a sufficient expansion / contraction amount can be obtained. Therefore, the bellows 22 can be housed in the expansion valve body 6 so as not to project from the expansion valve body 6 as in the embodiment. Therefore, unlike the conventional case, not only the expansion valve can be downsized, but also the bellows 22 is not exposed to the outside air, so that the bellows 22 is hardly affected by the outside air temperature, and the bellows 22 does not fluctuate in the refrigerant temperature. And expands and contracts accurately to enable accurate control of the refrigerant amount.

In addition, if the bellows 22 is covered with the cover 19 as in the embodiment, and the cover 19 is made of synthetic resin, the bellows 22 and the outside air are shut off,
The influence of the outside temperature can be further reduced. Moreover, in the embodiment, the bellows 22 is not in contact with the peripheral wall of the cover 19 or the expansion valve body 6, but the bellows 22 is only in contact with the cover 19 and the temperature sensitive rod 25 at the upper and lower ends. Therefore, the temperature of the expansion valve body 6 is not transmitted to the bellows 22, and the bellows 22 is not affected by the outside air temperature via the body 6. Further, when the inert gas in the bellows 22 is adsorbed by the activated carbon as in the embodiment, the temperature change of the inert gas is accompanied by the temperature change of the activated carbon. That is, the temperature of the inert gas alone does not change, and the temperature of the inert gas requires some time. For this reason, the shape change of the bellows 22 is appropriately delayed with respect to the change of the refrigerant temperature, whereby hunting of the entire refrigeration cycle can be prevented.

The present invention is not limited to the above embodiment, but the above embodiment describes the box type expansion valve in which the low pressure refrigerant passage is also integrated. However, for example, a type without this low pressure refrigerant passage It may be used for the expansion valve.

[0025]

As described above in the embodiments,
In the first aspect of the present invention, since the greenhouse is made up of bellows, the entire size can be reduced, and the effect of the outside air temperature can be avoided and the amount of refrigerant can be accurately adjusted.

Further, in the second aspect of the invention, since the bellows is covered with the cover, it is possible to more reliably avoid the influence of the outside temperature.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a car air conditioner of an embodiment.

[Explanation of symbols]

2 ... condenser, 5 ... evaporator, 6 ... expansion valve body,
8 ... Expansion orifice, 9 ... Liquid refrigerant passage, 10 ... Atomized refrigerant passage, 12 ... Valve body, 17 ... Low pressure refrigerant passage, 19 ... Cover, 22 ... Bellows.

Claims (2)

[Claims] 1. A liquid refrigerant passage formed in the expansion valve main body and communicating with a condenser to introduce a refrigerant condensed by the condenser; and a liquid refrigerant passage formed in the expansion valve main body with respect to the liquid refrigerant passage. A mist-like refrigerant passage that communicates through an expansion orifice and supplies a refrigerant adiabatically expanded by the orifice to an evaporator, a valve body that adjusts the opening / closing amount of the expansion orifice, and is formed in the expansion valve body, A low-pressure refrigerant passage into which the refrigerant that has passed through the evaporator is introduced, a temperature-sensing member provided in the low-pressure refrigerant passage, and the expansion valve body provided in contact with the temperature-sensing member and transmitted from the temperature-sensing member. A temperature-sensitive greenhouse that expands and contracts according to a temperature change, and a transmitter that is interposed between the temperature-sensitive greenhouse and the valve body and that transmits the expansion and contraction operation of the temperature-sensitive greenhouse to the valve body as the opening and closing amount adjusting operation. When the more becomes the expansion valve, the expansion valve, characterized by being configured by the sense greenhouse bellows filled with an inert gas. 2. The expansion valve according to claim 1, wherein the bellows is covered with a cover fixed to the expansion valve body.