JP2012229886A - Temperature expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature expansion valve which can be used for a large-capacity refrigeration cycle, and in which pressure balance is not disrupted with a simple structure, and variation in overheat degree setting values is reduced even against variation of primary pressure.SOLUTION: A columnar needle part 15b to be inserted into a guide hole 14 is formed on a valve body 15. The outer diameter of the needle part 15b is made equal to the inner diameter of a valve port 13. The end of the needle part 15b is connected to a diaphragm 23 via a dolly block 17 in the uniform pressure chamber 22a of a diaphragm device 2. A sealing member 6 is attached to the needle part 15b. The sealing member 6 is constituted of a disk shaped packing 61 and a leaf spring 62. A rim part 61a is formed by bending and deforming the outer periphery of the packing 61 to the valve port 13 side. The rim part 61a is pressed to the inner peripheral surface side of the guide hole 14 by the leaf spring 62. By the sealing member 6, a part between the uniform pressure chamber 22a and a first port 11 is sealed.

Description

  The present invention relates to a temperature expansion valve used for controlling the degree of superheat of a refrigeration cycle by automatically adjusting a valve opening degree in response to an outlet side temperature of an evaporator in a refrigeration cycle.

  Conventionally, as a temperature expansion valve, for example, there is one disclosed in JP-A-5-340479 (Patent Document 1). The temperature expansion valve of Patent Document 1 includes a temperature sensing cylinder that senses the temperature of the outlet side piping of the evaporator, and exerts the pressure of the temperature sensing cylinder on the diaphragm device. When the refrigerant from the primary side pipe on the condenser side of the temperature expansion valve flows out to the secondary side pipe through the valve port, the opening degree of the valve port is controlled by the valve body.

  In the diaphragm device, a pressure receiving chamber and a pressure equalizing chamber are partitioned by the diaphragm, and a temperature sensing cylinder is communicated with the pressure receiving chamber. Further, a rod is abutted against the valve element normally biased in the closing direction, and this rod is connected to the diaphragm via a metal abutment. The rod is supported by the bush, and the gap between the bush and the rod is sealed by a packing pressed by a spring in order to prevent the influence of the primary pressure on the pressure equalizing chamber.

JP-A-5-340479

  As in Patent Document 1, the structure in which the gap between the bush and the rod is sealed with a packing and a spring has room for improvement when applied to a temperature expansion valve used in a refrigeration cycle having a medium capacity to a large capacity. In other words, in order to eliminate the influence of the primary pressure acting on the rod, it is necessary to make the shaft diameter of the rod equal to the valve port diameter. End up. For this reason, a spring (spring) having a large load that can overcome the differential pressure between the primary pressure and the evaporation pressure is required, the wire diameter of the spring is increased, and the valve housing needs to be enlarged. For this reason, in the refrigeration cycle of medium capacity or more, in order to avoid excessive enlargement of the valve housing, it is a structure that is easily influenced by the primary pressure, or in order to eliminate the influence of the primary pressure in the conventional structure as described above, Separately, a pressure equalizing flow path is provided, resulting in a complicated structure and high cost.

  It is an object of the present invention to provide a temperature expansion valve that can be used for a large-capacity refrigeration cycle and that does not lose the pressure balance with a simple structure and that has a small change in superheat degree setting value even with respect to a change in primary pressure. And

  The temperature expansion valve according to claim 1 is connected between a condenser and an evaporator of a refrigeration cycle, and is connected to a pressure from a temperature sensing cylinder provided in an outlet side pipe of the evaporator and an evaporation pressure of the evaporator. A temperature expansion valve provided with a diaphragm device for controlling an opening degree of a valve port for flowing a refrigerant from a primary pipe on the condenser side to a secondary pipe on the evaporator side according to a differential pressure, A first port to be connected and a second port connected to the secondary pipe are formed across the valve port, and the first port is a guide hole opened on a side portion, and the valve port side is A cylindrical guide hole having an axial line as a central axis of the valve port at one end is formed, a valve housing in which a pressure equalizing passage communicating with an outlet side pipe of the evaporator is formed, and the guide hole in the guide hole It is accommodated so as to be movable in the axial direction, and with respect to the valve port A valve portion that opens and closes the valve port and is located on the second port side, and a cylindrical needle portion that is fitted into the guide hole, and the side of the needle portion that is opposite to the valve portion of the diaphragm device A valve body connected to the diaphragm; a superheat degree setting portion that biases the valve body toward the diaphragm; and a plate-like packing that is provided on the needle portion of the valve body and contacts the inner peripheral surface of the guide hole. And a sealing member comprising a leaf spring that urges the packing toward the inner peripheral surface side of the guide hole, and the diaphragm device is attached to the end of the guide hole of the valve housing, and A pressure equalizing chamber into which the evaporation pressure of the outlet side pipe of the evaporator is introduced via a pressure path, and the packing of the seal member is formed in an annular shape around the needle portion, A rim portion is formed by bending and deforming the outer peripheral end toward the valve port side with respect to the axial direction, and the rim portion of the packing is pressed against the inner peripheral surface of the guide hole by the elastic force of the leaf spring. The sealing member seals the pressure equalizing chamber and the first port.

  A temperature expansion valve according to a second aspect is the temperature expansion valve according to the first aspect, wherein an outer diameter of the needle portion is the same as an inner diameter of the valve port.

  The temperature expansion valve according to claim 3 is the temperature expansion valve according to claim 1 or 2, wherein the packing of the seal member is made of a polytetrafluoroethylene (PTFE) material.

  According to the temperature expansion valve of claim 1, in the temperature expansion valve in which the needle portion of the valve body connected to the diaphragm device is fitted into the guide hole, the packing is formed in an annular shape around the needle portion of the valve body. The rim portion formed by bending and deforming the outer peripheral end toward the valve port side with respect to the axial direction is formed, and the rim portion is pressed against the inner peripheral surface of the guide hole by the elastic force of the leaf spring, so that the diaphragm device side Since the pressure equalization chamber and the first port on the primary pressure side are sealed, the pressure balance is not disrupted with a simple structure. Can do.

  According to the temperature expansion valve of the second aspect, in addition to the effect of the first aspect, since the outer diameter of the needle portion of the valve body and the inner diameter of the valve port are made the same size, the fluctuation of the primary pressure is given to the valve body. The influence can be reduced.

  According to the temperature expansion valve of the third aspect, in addition to the effect of the first or second aspect, since the packing is made of a polytetrafluoroethylene material, it is possible to suppress the hysteresis during the superheat degree control.

It is a longitudinal cross-sectional view of the temperature expansion valve of embodiment of this invention. It is a principal part expanded sectional view of the temperature expansion valve of embodiment of this invention. It is a figure which shows the state before the assembly | attachment of the packing and leaf | plate spring of the temperature expansion valve of embodiment of this invention. It is a figure which shows the shape of the assembly state of the packing and leaf | plate spring of the temperature expansion valve of embodiment of this invention. It is a figure which shows the principal part of the refrigerating cycle to which the temperature expansion valve of embodiment of this invention is applied.

  Next, an embodiment of the temperature expansion valve of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of the temperature expansion valve of the embodiment, FIG. 2 is an enlarged sectional view of a main part of the temperature expansion valve of the embodiment, and FIG. 3 is a state before assembly of the seal packing and leaf spring of the temperature expansion valve of the embodiment FIG. 4 is a view showing an assembled state of the seal packing and leaf spring of the temperature expansion valve of the embodiment, and FIG. 5 is a view showing a main part of a refrigeration cycle to which the temperature expansion valve of the embodiment is applied. .

  In FIG. 5, 10 is the temperature expansion valve of the embodiment, 20 is a compressor, 30 is a condenser, and 40 is an evaporator. These are connected in a ring shape by piping to constitute a refrigeration cycle. The primary side joint pipe 1a of the temperature expansion valve 10 is connected to the primary pipe a on the condenser 30 side, the secondary side joint pipe 1b is connected to the secondary pipe b on the evaporator 40 side, and the pressure equalizing pipe 1c is the evaporator. It is connected to 40 outlet side pipes c. The compressor 20 compresses the refrigerant, and the compressed refrigerant is condensed and liquefied by the condenser 30 and flows into the temperature expansion valve 10 through the primary side joint pipe 1a. The temperature expansion valve 10 depressurizes (expands) the inflowing refrigerant and causes the refrigerant to flow into the evaporator 40 from the secondary side joint pipe 1b. The evaporator 40 evaporates the refrigerant and circulates it through the compressor 20. A temperature sensing cylinder 10 </ b> A of the temperature expansion valve 10 is attached to the outlet side pipe c of the evaporator 40. The temperature sensing cylinder 10A is filled with, for example, the same gas (and liquid) as the refrigerant in the refrigeration cycle, and the temperature sensing cylinder 10A is connected to the diaphragm device 2 of the temperature expansion valve 10 by a capillary tube 10B.

  As shown in FIG. 1, the temperature expansion valve 10 has a metal valve housing 1, which is connected to the first port 11 connected to the primary pipe a and the secondary pipe b. A second port 12 is formed, and a valve port 13 is formed between the first port 11 and the second port 12. Further, the valve housing 1 is formed with a guide hole 14 in which the first port 11 is opened to the side. The guide hole 14 has a cylindrical shape with the valve port 13 side as one end and the central axis of the valve port 13 as the axis L, and the side opposite to the valve port 13 is open. Further, the valve housing 1 is formed with a pressure equalizing path 22 b communicating with the outlet side pipe c of the evaporator 40. Further, a substantially cylindrical mounting hole 16 having an axis L as an axis is formed in the lower portion of the valve port 13. A primary side joint pipe 1a is attached to the first port 11, a secondary side joint pipe 1b is attached to the second port 12, and a pressure equalization pipe 1c is attached to the pressure equalization path 22b.

  A valve body 15 is disposed in the guide hole 14 of the valve housing 1. The valve body 15 has a clearance with respect to the valve portion 15 a located on the second port 12 side with respect to the valve port 13 and the inner peripheral surface of the guide hole 14, and has a cylindrical shape that is inserted into the guide hole 14. And a needle portion 15b. Accordingly, the valve body 15 is accommodated in the guide hole 14 so as to be movable in the axis L direction, and the valve portion 15a opens and closes the valve port 13 by the movement in the axis L direction. Further, the end of the needle portion 15b opposite to the valve portion 15a is fitted with a metal 17 and the valve body 15 is connected to the diaphragm 23 of the diaphragm device 2 via the metal 17.

  The superheat degree setting unit 3 is attached to the attachment hole 16 below the valve port 13. The superheat degree setting unit 3 includes an adjustment spindle 31 having an external thread on the outer periphery, an adjustment spring 32 disposed in the inner hole of the adjustment spindle 31, and a retainer 33 disposed at an end of the adjustment spring 32. I have. In the adjustment spindle 31, a male screw is screwed into a female screw formed in the lower portion of the mounting hole 16. Note that an O-ring is attached to the adjustment spindle 31, and the airtightness between the valve port 13 and the attachment hole 16 is maintained. The retainer 33 is fitted to a boss portion 15a1 formed at the lower portion of the valve portion 15a. The valve body 15 is urged toward the valve closing direction for closing the valve port 13, that is, toward the diaphragm 23 by the spring force of the adjustment spring 32. Note that the biasing force applied to the valve body 15 by the adjustment spring 32 is adjusted by turning the adjustment spindle 31. A retaining ring 25 that prevents the adjustment spindle 31 from falling off is attached to the attachment hole 16.

  A ring-shaped recess 161 is formed around the opening at the lower end of the mounting hole 16, and a female screw 162 is formed around the inner side of the recess 161 in the axis L direction. A ring-shaped sealing member 4 made of polytetrafluoroethylene (PTFE) is disposed in the recess 161, and the lid member 5 is screwed into the female screw in the lower end portion of the mounting hole 16. It is attached by. In addition, the thickness of the sealing member 4 is formed to be thicker than the depth of the concave portion 161 as a component before attachment. By screwing the lid member 5, the sealing member 4 is slightly crushed and plastically deformed. , Fixed in the recess 161.

  A diaphragm device 2 is attached to the upper portion of the valve housing 1. The diaphragm device 2 has a case body constituted by an upper lid 21 and a lower lid 22, and the diaphragm device 2 is fitted to the end of the guide hole 14 by screwing the lower portion of the lower lid 22 to the upper end of the valve housing 1. It is attached. Further, a diaphragm 23 is provided between the upper lid 21 and the lower lid 22, and the inside of the case body composed of the upper lid 21 and the lower lid 22 is partitioned by the diaphragm 23 as a pressure receiving chamber 21a and a pressure equalizing chamber 22a. . The pressure equalizing chamber 22a is electrically connected to the outlet side pipe c of the evaporator 40 via the pressure equalizing path 22b of the valve housing 1, and the evaporation pressure of the outlet side pipe c is introduced into the pressure equalizing chamber 22a.

  The pressure receiving chamber 21a is connected to the temperature sensing cylinder 10A by a capillary tube 10B. Thereby, the internal pressure of the pressure receiving chamber 21a changes according to the temperature sensed by the temperature sensing cylinder 10A. The diaphragm 23 is displaced according to the pressure difference between the pressure receiving chamber 21 a and the pressure equalizing chamber 22 a, and this displacement is transmitted to the valve body 15 by the metal 17.

  That is, the temperature expansion valve 10 acts so that the valve body 15a opens the valve port 13 when the detected temperature of the outlet side pipe c of the evaporator 40 becomes higher, and when the detected temperature of the outlet side pipe c becomes lower. Acts to close 13. Further, when the evaporation pressure in the evaporator 40 becomes low, the valve body 15a acts to open the valve port 13, and when the evaporation pressure becomes high, the valve body 15a acts to close the valve port 13. In this way, the opening degree of the valve port 13 through which the refrigerant flows from the condenser-side primary pipe a to the evaporator-side secondary pipe b in accordance with the pressure difference between the temperature sensed by the temperature sensing cylinder 10A and the evaporation pressure. To control the degree of superheat of the refrigeration cycle.

  As shown in FIG. 2, a cylindrical large-diameter boss portion 15b1, a medium-diameter boss portion 15b2, and a small-diameter boss portion 15b3 are formed at the end of the needle portion 15b of the valve body 15, respectively. The small-diameter boss portion 15b3 is fitted into the central hole 17a of the gold 17 so that the gold 17 is attached to the end of the needle portion 15b.

  A seal member 6 is provided around the middle diameter boss portion 15b2 of the needle portion 15b. The seal member 6 includes a disc-like (donut disc-like) packing 61 made of polytetrafluoroethylene (PTFE) and a disc-like (donut disc-like) leaf spring 62 made of a metal material. The spring 62 is fitted in the medium diameter boss portion 15b2 with the leaf spring 62 facing the large diameter boss portion 15b1.

  As shown in FIG. 3A, the packing 61 has a flat plate shape in the state of the parts before assembly. Further, the leaf spring 62 has an uneven outer peripheral portion and a large number of convex tooth-shaped portions 62a. As shown in FIG. 3 (B), the leaf spring 62 is in a state where the convex tooth-shaped portion 62a is slightly bent in the state of the parts before assembly.

  The presser member 7 is fitted to the medium diameter boss portion 15b2 of the needle portion 15b. A ring-shaped protrusion 7a is formed on the end face of the holding member 7 on the large-diameter boss 15b1 side. Moreover, the circular recessed part 15b1-1 is formed in the end surface of the large diameter boss | hub part 15b1 in the position facing the said protrusion 7a. And in the state which pressed the protrusion 7a of the pressing member 7 against the packing 61, the end part of the holding member 7 side and the end part of the medium diameter boss | hub 15b2 of the needle part 15b are welded, and the pressing member 7 It is fixed to the needle portion 15b. Thus, the packing 61 of the seal member 6 is formed in an annular shape around the needle portion 15b.

  With the seal member 6 attached to the needle portion 15b as described above, in the assembled state in which these assemblies are fitted and inserted into the guide holes 14, as shown in FIG. A rim portion 61a is formed by bending and deforming toward the valve port 13 with respect to the axis L direction. In addition, the leaf spring 62 is in a state where the outer peripheral convex-tooth shaped portion 62 a is bent inside the rim portion 61 of the packing 61. The leaf spring 62 presses the rim portion 61a against the inner peripheral surface of the guide hole 14 by the elastic force of the convex tooth-shaped portion 62a. Therefore, although there is a clearance between the needle portion 15b and the inner peripheral surface of the guide hole 14, the space between the pressure equalizing chamber 22a and the first port 1a is completely sealed by the packing 61 of the seal member 6. Thus, the sealing member 6 provides a high sealing performance between the pressure equalizing chamber 22a and the first port 1a with respect to the differential pressure between the evaporation pressure introduced into the pressure equalizing pipe 1c and the primary pressure of the first port 11. It is done. Even if the primary pressure increases, the pressure acts to push the rim portion 61a of the packing 61 toward the inner peripheral surface of the guide hole 14, so that high sealing performance can be maintained.

In addition, since many convex-tooth shaped parts 62a of the leaf | plate spring 62 press in the position spaced apart from the inner side of the rim | limb part 61a of the packing 61, in order to prevent the rim | limb part 61a from becoming polygonal shape, it is packing 61. A thickness of about 0.3 mm to 0.5 mm is suitable. In addition, since the packing of the polytetrafluoroethylene material was used with this thickness, the hysteresis at the time of superheat degree control was able to be kept at 2 degrees C or less even if the maximum differential pressure was 3.0 MPa.

  Further, in the embodiment, since the outer diameter of the needle portion 15b of the valve body 15 is approximately the same as the inner diameter of the valve port 13, even if the primary pressure varies, the force due to the pressure on the valve body 15 The portion 15a side and the needle portion 15b side cancel each other, and the fluctuation of the primary pressure does not affect the valve body 15. Thus, since it has a simple structure for sealing with the seal member 6, the outer diameter of the needle portion 15 b is set to the inner diameter of the valve port 13 even in a large-capacity refrigeration cycle for increasing the flow rate of the refrigerant flowing through the valve port 13. Can be as large as Therefore, the set value fluctuation of the superheat degree can be reduced with respect to the fluctuation of the primary pressure.

  As described above, the inner diameter of the valve port 13 and the outer diameter of the needle portion 15b can be made the same, so that it can be used for a large-capacity refrigeration cycle, and a large spring is not required as in the prior art, thereby reducing the size and weight. it can.

  For example, in the past, when R22 was used as the refrigerant, the capacity of around 30 kW was the limit, but even if the valve housing is the same (common) as before, it can be applied to the capacity of 20 kW to 50 kW.

DESCRIPTION OF SYMBOLS 1 Valve housing 11 1st port 12 2nd port 13 Valve port 14 Guide hole 15 Valve body 15a Valve part 15b Needle part 2 Diaphragm device 21 Upper lid 21a Pressure receiving chamber 22 Lower lid 22a Pressure equalizing chamber 3 Superheat degree setting part 6 Seal member 61 Packing 61a Rim part 62 Leaf spring 62a Convex tooth shaped part 7 Presser member 10 Temperature expansion valve 10A Temperature sensitive cylinder 20 Compressor 30 Condenser 40 Evaporator

Claims (3)

The condenser is connected between a condenser and an evaporator of a refrigeration cycle, and the condenser is in accordance with a differential pressure between a pressure from a temperature sensing cylinder provided in an outlet side pipe of the evaporator and an evaporation pressure of the evaporator. A temperature expansion valve provided with a diaphragm device for controlling an opening degree of a valve port for flowing a refrigerant from a primary pipe on the side to a secondary pipe on the evaporator side,
A first port connected to the primary pipe and a second port connected to the secondary pipe are formed across the valve port, and the first port is a guide hole opened on a side, A valve housing in which a cylindrical guide hole having the valve port side as one end and an axis of the central axis of the valve port is formed, and a pressure equalizing path communicating with the outlet side pipe of the evaporator is formed;
A valve portion that is accommodated in the guide hole so as to be movable in the axial direction, is positioned on the second port side with respect to the valve port, and opens and closes the valve port, and a columnar shape that is inserted into the guide hole A valve body having a needle portion, and a side opposite to the valve portion of the needle portion is connected to the diaphragm of the diaphragm device;
A superheat degree setting section for urging the valve body toward the diaphragm;
A seal member comprising a plate-like packing provided on the needle portion of the valve body and contacting the inner peripheral surface of the guide hole, and a plate spring for biasing the packing toward the inner peripheral surface side of the guide hole;
With
The diaphragm device is attached to an end portion of the guide hole of the valve housing, and has a pressure equalization chamber into which the evaporation pressure of the outlet side pipe of the evaporator is introduced through the pressure equalization path,
The packing of the seal member is formed in an annular shape around the needle portion, and the packing forms a rim portion formed by bending and deforming an outer peripheral end thereof toward the valve port with respect to the axial direction, The pressure equalizing chamber and the first port are sealed by the seal member by pressing the rim portion of the packing against the inner peripheral surface of the guide hole by the elastic force of a leaf spring. A temperature expansion valve.   The temperature expansion valve according to claim 1, wherein an outer diameter of the needle portion is the same as an inner diameter of the valve port.   The temperature expansion valve according to claim 1 or 2, wherein the packing of the seal member is made of a polytetrafluoroethylene (PTFE) material.

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