JP2003176965A - Expansion valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a movement of a heat of a high temperature refrigerant to a low temperature refrigerant side via a valve body, in a supercooling degree control type expansion valve. <P>SOLUTION: An element 24a which senses a refrigerant temperature to displace a valve rod 12 is supported to a valve body 8 via a projection 80 formed to the valve body 8. By this constitution, since a contact area between the valve body 8 and the element 24a is made small, the heat of the high temperature refrigerant is restrained from moving to the low temperature refrigerant side via the valve body 8. Accordingly, temperature reduction of the refrigerant at a high pressure side can be prevented, and a temperature of the high pressure side refrigerant can be accurately sensed, whereby a valve opening can be properly controlled. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in the middle of a refrigerant flow passage connecting a high pressure side heat exchanger and a low pressure side heat exchanger of a vapor compression refrigerator, and opens a valve based on the high temperature side refrigerant temperature. It relates to an expansion valve that adjusts the degree to expand the refrigerant under reduced pressure.
It is effective when applied to a supercooling degree control type expansion valve that controls the valve opening degree so that the supercooling degree of the refrigerant at the refrigerant outlet of the high-pressure side heat exchanger becomes a predetermined value.

[0002]

2. Description of the Related Art A subcooling degree control type expansion valve senses the refrigerant temperature on the high pressure side, and the subcooling degree of the refrigerant at the refrigerant outlet of the high pressure side heat exchanger reaches a predetermined value. As described above, the valve opening is controlled so that an element for sensing the refrigerant temperature and controlling the valve opening is accommodated in the valve body.

On the other hand, since the valve body constitutes a part of the refrigerant flow path, the space filled with the high-temperature refrigerant before being depressurized and the refrigerant whose temperature has been lowered by expansion under reduced pressure are filled in the valve body. There is a space.

For this reason, the heat of the high-temperature refrigerant moves to the low-temperature refrigerant side via the valve body, and the refrigerant temperature on the high-pressure side decreases, so that the temperature of the high-pressure side refrigerant can be accurately sensed. Therefore, the valve opening may not be controlled appropriately.

To solve this problem, it is conceivable that the valve body is made of a material having a low thermal conductivity such as resin. However, in this means, the temperature condition of the vehicle engine room or the water environment Under severe conditions, the valve body may be distorted, so it is rather difficult to properly control the valve opening.

In view of the above points, the present invention has an object to suppress the heat of the high-temperature refrigerant from moving to the low-temperature refrigerant side via the valve body.

[0007]

In order to achieve the above object, the present invention provides a high-pressure side heat exchanger (3) and a low-pressure side heat exchanger of a vapor compression refrigerator according to the invention of claim 1. (4)
An expansion valve that is provided in the middle of a refrigerant flow path that connects to and that expands the refrigerant under reduced pressure by adjusting the valve opening degree based on the refrigerant temperature on the high pressure side. A valve body (8) having a valve port (16) for decompressing and expanding the refrigerant, a valve body (12) housed in the valve body (8) for adjusting the opening of the valve port (16), and a valve. The valve body (1) is housed in a portion of the body (8) filled with the high-pressure side refrigerant and senses the high-temperature side refrigerant temperature.
2) displacing the element (24a), the element (24a) is provided with a valve body (8) via a protrusion (80) formed on at least one of the element (24a) and the valve body (8). It is characterized by being supported by.

This makes it possible to reduce the contact area between the valve body (8) and the element (24a), so that the heat of the high-temperature refrigerant moves to the low-temperature refrigerant side through the valve body (8). Can be suppressed. Therefore, it is possible to prevent the refrigerant temperature on the high-pressure side from decreasing, so that the temperature of the high-pressure side refrigerant can be accurately sensed and the valve opening degree can be appropriately controlled.

The projection (80) may be integrally formed with the valve body (8) as in the second aspect of the invention. Further, as in the invention described in claim 3, the protrusion (8
0) may be integrally formed with the element (24a).

According to the fourth aspect of the invention, the high pressure side refrigerant is provided in the middle of the refrigerant flow path connecting the high pressure side heat exchanger (3) and the low pressure side heat exchanger (4) of the vapor compression refrigerator. An expansion valve for adjusting the valve opening degree based on the temperature to expand the refrigerant under reduced pressure, the valve having a valve port (16) for forming a refrigerant flow path and reducing the refrigerant flow for expansion under reduced pressure. Stored in the body (8) and the valve body (8),
The valve body (12) for adjusting the opening of the valve opening (16) and the valve body (8) are housed in a portion filled with the high pressure side refrigerant, and the valve body detects the high temperature side refrigerant temperature. An element (24a) for displacing (12), the element (24a) being made of a material having a smaller thermal conductivity than the valve body (8) arranged between the element (24a) and the valve body (8). Is supported by the valve body (8) via a spacer (85).

As a result, it is possible to prevent the temperature of the high-pressure side refrigerant from dropping, so that the temperature of the high-pressure side refrigerant can be sensed accurately and the valve opening can be controlled appropriately.

In the present invention, since the contact portion between the valve body (8) and the element (24a) is made of resin,
There is no problem even if it is installed in a severe environment such as the vehicle engine room.

Incidentally, the reference numerals in the parentheses of the above-mentioned means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment)
The expansion valve according to the present invention is applied to a vehicle air conditioner (vehicle vapor compression refrigerator), FIG. 1 is a schematic diagram of a vehicle vapor compression refrigerator, and FIG. 2 is related to the present embodiment. FIG. 3 is a cross-sectional view of the expansion valve, and FIG. 3 is an exploded part view of the part in which FIG. First, a vapor compression refrigerator will be described with reference to FIG.

The high-temperature, high-pressure refrigerant discharged from the compressor 1 driven by the driving body 1a such as a running engine is guided to the condenser 3 through the refrigerant pipe 2 and cooled and condensed by the condenser 3.

The refrigerant flowing out of the condenser 3 is decompressed and expanded by an expansion valve 5 of a supercooling degree control type and flows into an evaporator 4,
Heat is taken from the air blown into the passenger compartment to evaporate. In addition,
As described above, the supercooling degree control type expansion valve adjusts the valve opening so that the degree of supercooling of the refrigerant flowing out of the condenser 3 becomes a predetermined value.

The pressure sensor 6 as a pressure detecting device
Is whether or not the pressure of the refrigerant on the high pressure side is equal to or higher than a predetermined pressure,
Alternatively, the compressor 1 is detected by detecting whether or not the pressure is lower than a predetermined pressure.
The detection signal is sent to a control device (not shown) that controls the operating state of the device, the air volume of a blower that sends cooling air to the condenser 3, and the like. Incidentally, in the present embodiment, the pressure sensor 6
Is integrated with the expansion valve 5.

Next, the expansion valve 5 will be described with reference to FIGS.

FIG. 2 shows a state in which the pressure sensor 6 is integrally attached to the expansion valve 5, and a high-pressure refrigerant is fed from the upstream condenser 3 into the metallic valve body 8 that forms the base of the expansion valve 5. Come on. The valve body 8 has a substantially cubic shape, and the surface on which the pressure detection device 6 is attached is partially cylindrical and recessed.

Details of the basic structure and function of the expansion valve 5 are described in Japanese Patent Application Laid-Open No. 2000-220917 and are not the gist of the present invention. Therefore, detailed description thereof will be omitted. Only the structure relevant to the present invention will be described below.

The high-pressure refrigerant is a refrigerant passage 9 formed in the valve body 8 which is a port for receiving the refrigerant from the condenser 3.
Introduced from. A piping member is attached to the coolant channel 9, and a channel hole 10 reaching the central portion of the valve body 8 is formed therein. A valve rod advancing / retreating hole 11 is formed in the central portion of the valve body 8 so as to intersect the flow path hole 10 at a right angle, and the valve rod advancing and retracting hole 11 communicate with each other. In addition, this refrigerant channel 9
A charge valve (not shown) is provided on one surface of the valve body 8 so as to communicate with the above and to seal the refrigerant in the vapor compression refrigerator.

A valve rod 12 is inserted into the valve rod advancing / retreating hole 11 so as to be able to move forward and backward, and a diaphragm receiving plate 13 having a large diameter portion is provided at one end of the valve rod 12. Further, the valve rod 12 is provided with a small-diameter neck lower portion 13a integral with the diaphragm receiving plate 13.

A coil spring 1 is provided on the outer periphery of the lower neck 13a.
4 is inserted and arranged, and the coil spring 14 is the valve rod 1
2 is always urged in the direction of pressing the diaphragm receiving plate 13 side. A conical valve 15 is formed at the other end of the valve rod 12 and faces a valve seat hole 16 provided in the valve body 8. The valve seat hole 16 communicates with a flow path 17 to the evaporator 4.

The valve body 8 has a valve rod 12
A small hole 18, which is a flow path for the refrigerant, is provided at a position parallel to the hole. This small hole 18 corresponds to the flow path hole 10 described above.
And the coil spring insertion space 19 are communicated with each other. On the other hand, the diaphragm receiving board 13 is arranged in a space position sandwiched between the diaphragm supporting member 20 and the diaphragm pressing member 21.

On the other hand, between the diaphragm supporting member 20 and the diaphragm pressing member 21, a disk-shaped diaphragm 22 of a flexible thin film is sandwiched and fixed, and this fixing causes the refrigerant to be exposed to the outside. It is integrated by welding to prevent leakage.

The diaphragm receiving plate 13 is in contact with the central portion of the diaphragm 22. Further, the diaphragm supporting member 20, the diaphragm pressing member 21, and the diaphragm 22 may be integrated by pressing with the diaphragm receiving plate 13 inserted.

A plurality of slit grooves 20a are arranged at equiangular positions in the contact portion between the lower surface (on the drawing) of the diaphragm support member 20 and the valve body 8, and the slit grooves 20a are formed in the flow path. A coolant flow path from the hole 10, the small hole 18, and the coil spring insertion space 19 is a part of a passage for guiding the coolant to the pressure sensor 6 side.

A concave portion is formed inside the central portion of the diaphragm pressing member 21, and gas is enclosed between the concave portion and the diaphragm 22. After filling the recess with gas, the gas inlet is sealed with the button 23 to form the power element chamber 24. It should be noted that the filled gas filled in the power element chamber 24 is preferably a gas having good temperature response such as R404a, R407, and R22.

The gas in the power element chamber 24 is
Since it expands and contracts due to the ambient heat, the valve rod 12 is displaced in the axial direction in conjunction with this, and the opening degree of the valve seat hole 16 is adjusted according to the temperature of the high pressure side refrigerant. That is, in this embodiment, the diaphragm support member 20, the diaphragm pressing member 21, and the diaphragm 22 constitute an element 24a that senses the refrigerant temperature on the high pressure side and displaces the valve rod 12.

The element 24a is supported by the valve body 8 by coming into contact with the tip end side of the projection 80 formed on the valve body 8. In this embodiment, the projection 80 extends around the valve rod 12. It is formed in a ring shape so as to surround it.

The protrusion 80 of the element 24a
The opposite side is pressed by a sensor element holder 37 described later, and the element 24a is fixed by being sandwiched between the protrusion 80 of the valve body 8 and the sensor element holder 37.

Further, a pressure sensor 6 described later is fixedly arranged on the upper portion (on the drawing) of the diaphragm pressing member 21. The pressure sensor 6 is inserted and fixed in a cylindrical space formed from one surface side of the valve body 8. The pressure sensor 6 inserted in the cylindrical space of the valve body 8 is
The thin-walled tip portion 8a of the valve body 8 is crimped inward by a crimping tool (not shown). The thin tip portion 8a presses the stepped portion 44 of the case 38 of the expansion valve 5, so that the expansion valve 5 and the pressure sensor 6 are integrated. Then, in order to maintain the airtightness between the valve body 8 and the pressure sensor 6, an O-ring 6a which is a hermetically sealing member is arranged at a corner portion of a sensor element holder 37 described later.

In the above structure, the refrigerant from the upstream is
It is guided to the coil spring insertion space 19 through the flow passage hole 10 and the small hole 18 of the valve body 8. The introduced refrigerant further passes through the slit groove 20a, and the flow path space 8b of the valve body 8 is
And is guided to the pressure sensor 6 side. Then, as the refrigerant flows through the valve body 8, the pressure of the gas enclosed in the power element chamber 24 changes depending on the pressure and temperature of the refrigerant.

This pressure change is balanced by the force pressing the diaphragm receiving plate 13 via the diaphragm 22 and the urging force of the coil spring 14, and the diaphragm receiving plate 13 is held at a predetermined position. This change in the position of the diaphragm receiving plate 13 causes the valve 15 of the valve rod 12 to change the cross-sectional area of the refrigerant passage with respect to the valve seat hole 16. By this holding, the refrigerant flow is throttled and the flow rate is adjusted.

That is, when the temperature of the refrigerant on the upstream side rises, the pressure in the power element chamber 24 moves to the direction in which the valve 15 is closed and the amount of refrigerant discharged decreases, so that the degree of supercooling of the refrigerant on the upstream side decreases. Grows larger. On the contrary, when the temperature on the upstream side decreases, the operation is performed reversely to the above. In this way, the degree of supercooling of the high pressure refrigerant on the upstream side is controlled. On the other hand, the refrigerant guided to the flow path space 8b is sent to the pressure sensor 6 attached to the cylindrical space portion of the valve body 8.

Next, the pressure sensor 6 will be described. The basic contents of the pressure sensor 6 are described in JP-A-11-35199.
It is described in detail in the No. 0 publication. The invention described in the publication is a pressure sensor of an absolute pressure type or a shield gauge pressure type, and these types are selected depending on the use environment, required accuracy, and the like.

The pressure sensor 6 is provided with a sensor element 30 having a pressure detecting element 31 which is a semiconductor element having a piezoresistive effect. The sensor element 30 is arranged and fixed at the position of the opening 34 at the center of the cylindrical sensor element holder 37. The outer periphery of the support base 32 that supports the pressure detection element 31 of the sensor element 30 has a thin collar portion 32a.

On the other hand, an annular protrusion 35 is formed on the outer periphery of the opening 34 of the sensor element holder 37. The collar portion 32a abuts on the annular protrusion 35, and the collar portion 32a and the annular protrusion 35 are airtightly welded and fixed to each other by welding. Therefore, the flow path space 8 which is a space between the sensor element holder 37 and the diaphragm pressing member 21.
space 36 defined by b and the sensor element 30
And are not in communication with each other, and therefore have different pressures.

The space 36 is a closed space in which atmospheric pressure is maintained. The refrigerant guided through the flow path space 8b reaches the pressure detection element 31 via the opening 34 at the center of the sensor element holder 37, and the pressure difference between the refrigerant and the space 36 is detected. As described above, since the pressure sensor 6 is fixed to the valve body 8 by keeping the airtightness between the pressure sensor 6 and the expansion valve 5 by the O-ring 6a or the like, the refrigerant does not leak to the valve body 8, and It is detected accurately.

In the present embodiment, the sensor element 30 is arranged in the central portion of the sensor element holder 37, but there are various forms of the sensor element 30 and the arrangement example is limited. Not a thing. The pressure sensor 6 is coupled to the valve body 8 by inserting the sensor element holder 37, the O-ring 6a, and the case 38, and then using the thin-walled tip portion 8a of the cylindrical portion of the valve body 8 as the coupling portion, and the step portion 44 of the case 38. Squeeze inside so as to embrace and integrate both without coming off.

This caulking connection ensures a reliable connection even when installed on the vehicle body of an automobile or the like without the risk of disconnection due to vibration. In the case of this caulking, the pressure sensor 6 cannot be removed. Although this caulking is performed on the pressure sensor 6 side by the thin-walled tip portion 8a on the valve body 8 side, conversely, it may be performed on the valve body 8 side from the pressure detecting drop 6 side.

An O-ring 6a is provided as a seal member on the outer circumference of the sensor element holder 37. This O
When the sensor element holder 37 is inserted into the valve body 8 by the ring 6a, the ring 6a abuts the inner diameter portion of the cylindrical portion of the valve body 8 and maintains airtightness to form the flow passage space 8b and the airtight space 36.

However, the hermetic sealing member is the O-ring 6a.
It is not limited to. For example, it may be an elastic ring having an X-shaped cross section. It may be called packing. The refrigerant sent to the valve body 8 side is sent into the expansion valve through the small hole 18, the coil spring insertion space 19, the slit groove 20a formed in the diaphragm support member 20, and the flow path space 8b, and the pressure and temperature changes. The valve rod 12 is operated to adjust the flow path on the expansion valve side, and the pressure of the refrigerant is detected on the pressure detection device side, thereby achieving two functions integrally.

Next, the function and effect of this embodiment will be described.

In this embodiment, the element 24a is supported by the valve body 8 via the projection 80 formed on the valve body 8, so that the contact area between the valve body 8 and the element 24a can be reduced. it can.

Therefore, it is possible to prevent the heat of the high-temperature refrigerant from moving to the low-temperature refrigerant side via the valve body 8, so that it is possible to prevent the refrigerant temperature on the high-pressure side from decreasing. Furthermore, since the temperature of the high-pressure side refrigerant can be sensed accurately, the valve opening can be controlled appropriately.

(Second Embodiment) In the first embodiment, the protrusion 80 is provided on the valve body 8, but in the present embodiment, the protrusion 80 is provided on the element 24a as shown in FIG. is there.

(Third Embodiment) In the above-mentioned embodiment, the valve body 8 or the element 24a is provided with the projection 80 to reduce the contact area between the element 24a and the valve body 8. , The valve body 8 is provided between the element 24a and the valve body 8.
The structure is such that the element 24a is supported through a ring-shaped spacer 85 made of a material having a smaller thermal conductivity.

As a result, the heat of the high-temperature refrigerant can be prevented from moving to the low-temperature refrigerant side via the valve body 8, so that the refrigerant temperature on the high-pressure side can be prevented from lowering. Furthermore, since the temperature of the high-pressure side refrigerant can be sensed accurately, the valve opening can be controlled appropriately.

In this embodiment, since the contact portion between the valve body 8 and the element 24a is made of resin, there is no problem even if it is mounted in the vehicle engine room.

(Fourth Embodiment) In the above-described embodiment, the pressure sensor is used as the pressure detecting device, but in the present embodiment, instead of this, a pressure switch 60 as shown in FIGS. Is. .

Incidentally, FIG. 6 shows an example in which the pressure switch 60 is integrated with the expansion valve 5 according to the first embodiment, and FIG. 7 shows an example in which the pressure switch 60 is integrated with the expansion valve 5 according to the second embodiment. 8 is an example in which the pressure switch 60 is integrated with the expansion valve 5 according to the first embodiment.

The mechanical structure of the pressure switch 60 is the same as that described in Japanese Patent Publication No. 7-114094. Specifically, the refrigerant sent from the flow path space 8b side of the expansion valve 5 is guided to the opening 51 of the pressure detection device 60 and drives the diaphragm 61. Diaphragm 6
When 1 is driven, the snap disk 62 in contact with it is pressed. When the snap disk 62 is pressed, the snap disk 63 is pressed in conjunction with this.

The diaphragm 61 is supported between the O-ring 6a and the end portion 71a of the case 71 of the pressure detecting device 60. The O-ring 6a is arranged between the end portion 71a of the case 71 and the diaphragm support member 72, and keeps the flow path space 8b airtight. Therefore, when the diaphragm 61 is driven by the pressure of the refrigerant from the flow path space 8b, the operation rods 64 and 65 are operated via the snap disks 62 and 63. When the actuating rods 64 and 65 are actuated, the contact 6
6, 67 or contacts 68, 69 are disconnected.

(Other Embodiments) In the above-mentioned embodiments, the pressure detecting device is integrated, but the present invention is not limited to this.

Further, in the above-described embodiment, the vapor compression refrigerator using CFC as the refrigerant is used. However, like the vapor compression refrigerator using carbon dioxide as the refrigerant, the refrigerant pressure on the high pressure side is the critical pressure of the refrigerant. It can also be applied to the expansion valve of the above vapor compression refrigerator.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vapor compression refrigerator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the expansion valve according to the first embodiment of the present invention.

FIG. 3 is an exploded part view of the part in which FIG. 2 is shown three-dimensionally.

FIG. 4 is a sectional view of an expansion valve according to a second embodiment of the present invention.

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

FIG. 6 is a sectional view of an expansion valve according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of an expansion valve according to a modification of the fourth embodiment of the present invention.

FIG. 8 is a sectional view of an expansion valve according to a modification of the fourth embodiment of the present invention.

[Explanation of symbols]

8 ... Valve body, 12 ... Valve rod, 16 ... Valve seat hole, 24 ...
Power element chamber, 24a ... Element, 80 ... Projection portion.

Continued front page    (72) Inventor Shigeki Ito             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO

Claims (4)

[Claims] 1. A valve opening provided in the middle of a refrigerant flow path connecting a high-pressure side heat exchanger (3) and a low-pressure side heat exchanger (4) of a vapor compression refrigerator, and based on a refrigerant temperature on the high-pressure side. An expansion valve for decompressing and expanding the refrigerant by adjusting the valve body (8), which constitutes a refrigerant flow path and has a valve port (16) for restricting and expanding the refrigerant by decompressing the refrigerant flow; The valve body (8) is housed in the valve body (8).
6) a valve body (12) for adjusting the opening of the valve body, and a valve body (8) housed in a portion of the valve body (8) filled with the high pressure side refrigerant, and sensing the high temperature side refrigerant temperature to detect the valve body ( 12) for displacing the element (24a), wherein the element (24a) is the element (24a).
An expansion valve, which is supported by the valve body (8) via a protrusion (80) formed on at least one of (a) and the valve body (8). 2. The projection (80) is integrally formed with the valve body (8).
The expansion valve described in. 3. The expansion valve according to claim 1, wherein the protrusion (80) is integrally formed with the element (24a). 4. A valve opening provided in the middle of a refrigerant flow path connecting a high pressure side heat exchanger (3) and a low pressure side heat exchanger (4) of a vapor compression refrigerator, and based on the refrigerant temperature on the high pressure side. An expansion valve for decompressing and expanding the refrigerant by adjusting the valve body (8), which constitutes a refrigerant flow path and has a valve port (16) for restricting and expanding the refrigerant by decompressing the refrigerant flow; The valve body (8) is housed in the valve body (8).
6) a valve body (12) for adjusting the opening of the valve body, and a valve body (8) housed in a portion of the valve body (8) filled with the high pressure side refrigerant, and sensing the high temperature side refrigerant temperature to detect the valve body ( 12) for displacing the element (24a), wherein the element (24a) is the element (24a).
supported by the valve body (8) via a spacer (85) made of a material having a smaller thermal conductivity than the valve body (8) disposed between the valve body (8) and the valve body (8); Expansion valve characterized by.