JP3920058B2 - Expansion valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion valve, and in particular, a high-temperature / high-pressure liquid refrigerant is adiabatically expanded into a low-temperature / low-pressure gas-liquid mixed refrigerant in a refrigeration cycle of an automotive air conditioner system, and the state of the refrigerant at an evaporator outlet is predetermined. The present invention relates to an expansion valve that controls the flow rate of refrigerant so that the degree of superheat is reached.
[0002]
[Prior art]
In automotive air-conditioning systems, high-temperature and high-pressure gas refrigerant compressed by a compressor is condensed by a radiator, and the condensed liquid refrigerant is adiabatically expanded by an expansion valve to form a low-temperature and low-pressure refrigerant, which is evaporated by an evaporator. Thus, a refrigeration cycle that returns to the compressor is formed. The evaporator supplied with the low-temperature refrigerant is cooled by exchanging heat with the air in the passenger compartment.
[0003]
The expansion valve senses changes in the temperature and pressure of the refrigerant on the evaporator outlet side, and controls the flow rate of refrigerant supplied to the evaporator inlet side based on the temperature rise and fall pressure of the temperature sensing part. And a valve portion to be configured. The valve portion includes a valve hole formed in a wall provided so as to block the refrigerant passage in the middle of a refrigerant passage communicating the refrigerant inlet for receiving the high-pressure refrigerant and the refrigerant outlet for supplying the low-pressure refrigerant, It consists of the valve body provided so that contact and separation were possible facing the hole. The valve body is urged by a spring in a direction to close the valve hole, and is controlled by a temperature sensing unit via a shaft to control the valve opening.
[0004]
Such an expansion valve is attached to the inlet pipe and outlet pipe of the evaporator, but the piping work between the expansion valve and the evaporator is very complicated, so the expansion valve is integrated with the evaporator to perform piping work. It has been proposed to mitigate.
[0005]
As an example, an evaporator with an expansion valve described in JP-A-63-80169 is known. According to this evaporator, a plurality of plates are laminated so that refrigerant flow passages and air circulation spaces are alternately formed, and a plurality of refrigerant flow passages are grouped at both ends of the laminated plates in the refrigerant flow direction. Tanks to be assembled are formed, and these tanks are appropriately connected to form a continuous refrigerant flow. The tank is provided with an expansion valve pipe to which a high pressure pipe for introducing a high pressure liquid refrigerant and a low pressure pipe constituting an evaporator outlet pipe are connected, and one end of the expansion valve pipe extends outside the evaporator. From there, the cylinder block constituting the expansion valve is inserted into the expansion valve pipe. The cylinder block includes a valve section that adiabatically expands the high-pressure liquid refrigerant and a control section that controls the valve body of the valve section by sensing the temperature and pressure of the refrigerant at the evaporator outlet.
[0006]
The pipe for the expansion valve is provided with a hole for supplying the adiabatic and expanded refrigerant to the evaporator inlet and a hole for allowing the refrigerant at the evaporator outlet to pass through the side wall of the cylinder block communicating with these holes. The refrigerant flow passage is sealed by a seal ring disposed between the expansion valve pipe and the cylinder block.
[0007]
In addition, the applicant of the present application, in Japanese Patent Application No. 2000-219744, is inserted into a valve case that is widened toward the outside in the middle of the evaporator inlet-side piping and has a large diameter portion open to the atmosphere. And an expansion valve that is fixed in this way. Such an expansion valve is provided with a diaphragm-type temperature sensing part in which a diaphragm for sensing the temperature and pressure of the refrigerant is held between an upper housing and a lower housing, and a room is formed on both sides of the diaphragm. . The valve case is integrally formed of the same aluminum as the evaporator and piping, and the housing of the temperature sensing part is formed of stainless steel.
[0008]
[Problems to be solved by the invention]
However, since the conventional expansion valve is configured to cut a solid cylindrical body and accommodate the valve body and the temperature sensing portion for driving the solid cylindrical body, the expansion valve is attached with a seal ring attached. When inserting into the expansion valve pipe, there is a risk that a hole provided in the expansion valve pipe may break the seal ring, resulting in poor assembly of the expansion valve.
[0009]
In addition, in an expansion valve that is inserted into the valve case and fixed from the side that is open to the atmosphere, the outer peripheral part of the housing of the temperature sensing part is fixed in close contact with the large-diameter outer peripheral part of the valve case. However, this part is exposed to the atmosphere, and since there is a large potential difference (standard electrode potential) between the stainless steel of the housing of the temperature sensing part and the aluminum of the valve case, if moisture intervenes between these metals However, there is a problem that a foreign metal contact corrosion phenomenon occurs and the aluminum valve case is corroded.
[0010]
The present invention has been made in view of the above points, and provides an expansion valve that is easy to assemble with a seal ring attached and that does not cause a dissimilar metal contact corrosion phenomenon when mounted on a valve case. For the purpose.
[0011]
[Means for Solving the Problems]
In the present invention, in order to solve the above problem, in an expansion valve that is attached to a valve case that is integrally welded to a space between an inlet side tank and an outlet side tank of an evaporator, A temperature sensing part for sensing the temperature and pressure of the refrigerant, a part constituting the room of the temperature sensing part for introducing the refrigerant in the outlet side tank, and a first chamber into which the refrigerant is introduced or led out are constituted. A valve portion having a housing having an outer shape in which the diameter and the portion constituting the second chamber into which the refrigerant is led out or introduced are sequentially reduced in stages, and a step portion which is sequentially reduced in diameter in the housing. 1 seal ring, second seal ring and third seal ring and between the first seal ring and the second seal ring and between the second seal ring and the third seal ring A connecting portion for connecting the mutually is provided an expansion valve, characterized in that it comprises a and a seal member that is integrally molded.
[0012]
According to such an expansion valve, since the first to third seal rings have the integrally formed seal member, it is possible to mount the seal member on the valve portion in one time. When the first to third seal rings attached to the part are independent, the diameter is reduced in the direction of insertion of the expansion valve into the valve case, so that it is easy to drop off. As a result, it is difficult to drop off and the assemblability with the seal ring attached is improved.
[0013]
In the present invention, the seal member has an electrically insulating thin film packing integrally formed so as to spread outward from the first seal ring. As a result, since the packing is interposed between the lower housing of the temperature sensing unit and the valve case when mounted on the valve case, no potential difference is generated even if moisture is interposed between them, and the dissimilar metal contact Since the corrosion phenomenon does not occur, the valve case is not corroded.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is an exploded explanatory view showing the relationship between an expansion valve and an evaporator according to the present invention, FIG. 2 is a plan view of a seal member, FIG. 3 is a front view showing a state in which the expansion valve according to the present invention is mounted on the evaporator, and FIG. It is a figure which shows an example of a fixing metal fitting, Comprising: (A) shows the side surface of a fixing metal fitting, (B) has shown the plane of the fixing metal fitting.
[0015]
The expansion valve 1 according to the present invention includes a temperature sensing part 2 and a valve part 3 that are integrally formed, and a seal member 4. The temperature sensing unit 2 includes a gas filling chamber 6 and a refrigerant introduction chamber 7 that are partitioned by a diaphragm 5. The gas filling chamber 6 is filled with the same gas as the refrigerant, and the refrigerant introduction chamber 7 has an opening 8 through which the refrigerant is introduced, and the diaphragm 5 controls the temperature and pressure of the refrigerant. It can be perceived.
[0016]
Under the temperature sensing unit 2, a first room 9 and a second room 10 are provided. The first chamber 9 is provided with an opening 11 for introducing a high-temperature / high-pressure liquid refrigerant, and the second chamber 10 is open at the lower part, and passes through the valve unit 3 to lower the temperature / The opening 12 is for leading out the low-pressure refrigerant.
[0017]
The lower housing of the temperature sensing unit 2 and the housing of the valve unit 3 are integrally formed, and the upper housing of the temperature sensing unit 2 is welded thereto. The integrally formed lower housing of the temperature sensing unit 2 and the housing of the valve unit 3 are stepped at portions forming the refrigerant introduction chamber 7 of the temperature sensing unit 2, the first chamber 9 and the second chamber 10 of the valve unit 3. And the refrigerant introduction chamber 7 and the first chamber 9 and the second chamber 10 of the valve portion 3 have an outer shape that is successively reduced in diameter in stages. The seal member 4 is fitted into these stepped portions.
[0018]
As shown in the plan view of FIG. 2, the seal member 4 includes three O-rings 13, 14, and 15 and a plurality of thin connection portions 16 that connect these to each other, and these are integrally formed. ing. The O-rings 13, 14, and 15 have an inner diameter corresponding to the outer diameter of the housing forming the refrigerant introduction chamber 7, the first chamber 9 and the second chamber 10 of the valve portion 3. Preferably, the inner diameter of at least one of the O-rings 13, 14, and 15 is slightly smaller than the outer diameter of the housing where the O-rings 13, 14, and 15 are mounted. Thereby, when the seal member 4 is fitted into the step portion of the housing, the seal member 4 does not fall off from the valve portion. In addition, since the three O-rings 13, 14, 15 are connected by the connection portion 16, the valve portion 3 can be mounted at the same time.
[0019]
Such an expansion valve 1 is inserted into a shallow valve case 22 formed integrally with the outside of the evaporator 21, and fixed by a fixing bracket 23.
The evaporator 21 has two plate-like heat exchange panels in which a plurality of refrigerant flow passages and air flow passages are alternately arranged, and two other heat exchange panels arranged on top of each other so as to be integrated. Each of the heat exchange panels is provided with a tank at each end in the fluid flow direction to collect the refrigerant flow passages, and the tanks of adjacent panels are connected to each other so that the refrigerant sequentially flows through the heat exchange panels. It is like that.
[0020]
The illustrated evaporator 21 shows a case where an inlet side tank 24 that receives the refrigerant from the expansion valve 1 and an outlet side tank 25 from which the evaporated refrigerant exits are arranged in parallel adjacent to each other. A valve case 22 for mounting the expansion valve 1 is attached to the space between the outlet 24 and the outlet side tank 25.
[0021]
The valve case 22 has a shape that is widened upward in the figure, and a refrigerant inlet pipe 26 that receives a high-pressure liquid refrigerant condensed by a condenser is connected to a side wall thereof. The refrigerant outlet pipe 27 of the evaporator 21 is directly connected to the outlet side tank 25.
[0022]
The evaporator 21 has a refrigerant introduction opening 28 on the inner side surface of the inlet side tank 24, and a refrigerant detection opening 29 on the inner side surface of the outlet side tank 25. The valve case 22 has a refrigerant outlet opening 30 for supplying a low-temperature and low-pressure refrigerant adiabatically expanded by the expansion valve 1 at a position aligned with the refrigerant inlet opening 28 of the inlet side tank 24, and the outlet side tank The refrigerant sensing opening 31 is configured to be able to sense the temperature and pressure of the refrigerant exiting from the evaporator 21 at a position aligned with the 25 refrigerant sensing openings 29. Although not shown, the valve case 22 has a refrigerant introduction opening for introducing high-pressure liquid refrigerant into a portion to which the refrigerant inlet pipe 26 is connected.
[0023]
The valve case 22 is welded and integrated with the evaporator 21 at the same time when the plate constituting the evaporator 21 is welded in the furnace.
The expansion valve 1 is inserted into such a valve case 22, and these are fixed by a fixture 23. The fixing bracket 23 has a slit-shaped opening 32 on the opposite side surface of an elastic strip formed in a substantially U shape, for example. In a state where the expansion valve 1 is inserted into the valve case 22, the overlapping portion is formed by pushing the fixing bracket 23 from the side into the portion where the entire circumference welded portion of the temperature sensing portion and the flange portion of the valve case 22 overlap. Is fitted into the slit-shaped opening 32, whereby the expansion valve 1 and the valve case 22 are fixed.
[0024]
FIG. 5 is a plan view showing another form of the seal member, FIG. 6 is a cross-sectional view taken along the line aa of FIG. 5, and FIG. 7 is a vertical cross-sectional view of a main part showing a state where the expansion valve is mounted on the evaporator. In these drawings, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals.
[0025]
The seal member 4a includes three O-rings 13, 14, and 15, a plurality of connecting portions 16 that connect them to each other, and a thin-film packing 33 that extends upward from the outer O-ring 13. A bead 34 is provided on the outer peripheral edge of the packing 33. The O-rings 13, 14, 15, the connecting portion 16, the packing 33, and the beads 34 are integrally formed of a non-conductive and flexible material such as rubber.
[0026]
When the expansion valve 1 is inserted into the valve case 22 and fixed with the fixing bracket 23, packing is interposed between the outer periphery welded portion of the temperature sensing portion 2 and the flange portion of the valve case 22, as shown in FIG. is doing. Thereby, the housing of the expansion valve 1 which is a part exposed to the atmosphere and the valve case 22 are electrically insulated by the packing 33. Here, the housing of the expansion valve 1 is made of stainless steel, and the valve case 22 is made of aluminum. However, even if moisture is present between these different metals, they are electrically insulated by the packing 33. No potential difference is generated, and the contact corrosion phenomenon of dissimilar metals does not occur and the aluminum valve case is not corroded.
[0027]
In addition, the aluminum valve case 22 is also in contact with the fixing fitting 23, and the fixing fitting 23 is plated with chromium having a small potential difference from aluminum so that the electric corrosion on the valve case 22 is reduced. Yes.
[0028]
【The invention's effect】
As described above, in the present invention, when attached to the valve case, the room of the temperature sensing unit necessary as an expansion valve, the first chamber into which the refrigerant is introduced or led out, and the refrigerant is led out or introduced. Three seal rings necessary for isolating the refrigerant passage communicating with the second chamber are connected and molded integrally. As a result, the diameter of the housing of the valve portion to which the seal ring is mounted is reduced in the direction of insertion into the valve case. As a result, it is difficult to drop off, and the three seal rings can be attached to the valve portion at a time, so that the assemblability with the seal ring attached is improved.
[0029]
Further, the present invention has an electrically insulating thin-film packing integrally formed so as to spread outward from a seal ring provided in the lower housing of the temperature sensing portion. As a result, when installed in the valve case, the packing electrically insulates between the lower housing of the temperature sensing part and the valve case. This prevents the valve case from corroding.
[Brief description of the drawings]
FIG. 1 is an exploded explanatory view showing a relationship between an expansion valve and an evaporator according to the present invention.
FIG. 2 is a plan view of a seal member.
FIG. 3 is a front view showing a state in which an expansion valve according to the present invention is mounted on an evaporator.
FIGS. 4A and 4B are diagrams illustrating an example of a fixing bracket, in which FIG. 4A illustrates a side surface of the fixing bracket and FIG. 4B illustrates a plane of the fixing bracket.
FIG. 5 is a plan view showing another form of the seal member.
6 is a cross-sectional view taken along the line aa in FIG. 5;
FIG. 7 is a longitudinal sectional view of a main part showing a state in which an expansion valve is mounted on an evaporator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Expansion valve 2 Temperature sensing part 3 Valve part 4, 4a Seal member 5 Diaphragm 6 Gas filling chamber 7 Refrigerant introduction chamber 8 Opening part 9 First chamber 10 Second chamber 11 Opening part 12 Opening parts 13, 14, 15 O Ring 16 Connecting portion 21 Evaporator 22 Valve case 23 Fixing bracket 24 Inlet side tank 25 Outlet side tank 26 Refrigerant inlet piping 27 Refrigerant outlet piping 28 Refrigerant opening 29 Refrigerant sensing opening 30 Refrigerant outlet 31 Opening 32 Opening 33 Packing 34 Bead

Claims (4)

In the expansion valve designed to be attached to a valve case integrally welded to the space between the inlet side tank and the outlet side tank of the evaporator,
A temperature sensing part for sensing the temperature and pressure of the refrigerant in the outlet side tank;
The portion constituting the room of the temperature sensing portion for introducing the refrigerant in the outlet side tank, the portion constituting the first chamber where the refrigerant is introduced or led out, and the second chamber where the refrigerant is led out or introduced A valve portion having a housing with an outer shape in which the diameters of the portions are sequentially reduced in diameter,
Between the first seal ring, the second seal ring, the third seal ring, the first seal ring, and the second seal ring, which are disposed in the stepped portion having a reduced diameter of the housing. A seal member in which a connecting portion for mutually connecting the second seal ring and the third seal ring is formed integrally;
An expansion valve characterized by comprising: 2. The expansion valve according to claim 1, wherein the seal member has an inner diameter of at least one of the first to third seal rings smaller than an outer diameter of the housing where the seal ring is mounted. . The expansion valve according to claim 2, wherein the seal member has an electrically insulating thin film packing integrally formed so as to spread outward from the first seal ring. The expansion valve according to claim 3, wherein the seal member has a bead on an outer peripheral edge of the packing.

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