Expansion valve

Abstract

To provide an expansion valve capable of connecting double piping and suppressing vibration of a valve body unit.SOLUTION: An expansion valve can be connected with double piping in which a low-pressure refrigerant passes the inside of inner piping and a high-pressure refrigerant passes an intermediate flow path as a space between the inner piping and outer piping disposed around the inner piping. The expansion valve includes: a valve body including a valve chamber having a valve seat and a high-pressure flow path in which a high-pressure refrigerant flows while being connected from the intermediate flow path to the valve chamber; and a valve body unit including a valve body that can be seated in the valve seat. The high-pressure flow path is formed while being tilted relative to an axis of the valve body unit such that a high-pressure refrigerant flowing through the high-pressure flow path from the intermediate flow path to the valve chamber hits against the valve body unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an expansion valve. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in refrigeration cycles used in air conditioners and the like mounted on automobiles, a temperature sensitive expansion valve is used which adjusts the amount of refrigerant passing through the valve in accordance with temperature.

[0003] In a general expansion valve, a high-pressure pipe through which the refrigerant is sent from the condenser of the refrigeration cycle and a low-pressure pipe through which the refrigerant is sent from the evaporator are connected separately. In contrast, the expansion valve disclosed in Patent Document 1 discloses a system in which a double pipe, with the low-pressure pipe as the inner pipe and the high-pressure pipe as the outer pipe, is connected to the expansion valve. This system simplifies the arrangement of the pipes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-94793 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the expansion valve is provided with a power element having a temperature-sensing part in which an inert gas or the like is sealed. The power element opens and closes the valve body via an actuating rod by utilizing the change in gas volume caused by heat transferred between the inside and outside of the temperature-sensing part. However, if the time constant of the temperature-sensing part is small, the valve body may vibrate and repeatedly open and close, which is called a hunting phenomenon. However, Patent Document 1 does not disclose a specific structure for suppressing the hunting phenomenon.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an expansion valve that can be connected to a double pipe and can suppress vibration of the valve body unit. [Means for solving the problem]

[0007] In order to achieve the above object, the expansion valve according to the present invention comprises: An expansion valve capable of connecting a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes through an intermediate flow passage that is a space between an outer pipe arranged around the inner pipe and the inner pipe, a valve chamber including a valve seat; A downstream side of the valve chamber and the valve chamber a valve body including a valve through hole as a connecting throttle and a high-pressure flow passage that is connected from the intermediate flow passage to the valve chamber and through which a high-pressure refrigerant flows; A valve body capable of being seated on the valve seat a valve body support including a body supporting the valve body and a flange portion formed on the body; A valve body unit including: an actuating rod disposed in the valve through hole and in contact with the valve body; A power element that drives the actuation rod; The actuator is disposed on the opposite side of the power element with the actuation rod interposed therebetween, The valve body unit is supported by the flange portion of the valve body support. and a coil spring for biasing the rotor toward the power element, The high-pressure refrigerant that flows from the intermediate passage to the valve chamber through the high-pressure passage is The flange portion of the valve body support The high pressure flow passage is formed at an angle with respect to the axis of the valve body unit so that the high pressure flow passage hits the 、 When the high pressure flow passage is projected along the axis of the high pressure flow passage, the projected image is in a valve closed state. The flange portion of the valve body support It is characterized in that it overlaps with. Effect of the Invention

[0008] According to the present invention, it is possible to provide an expansion valve which can connect to a double pipe and suppress vibration of the valve body unit. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example in which an expansion valve according to the present embodiment is applied to a refrigerant circulation system. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view showing the periphery of the valve body of this embodiment. [Diagram 3] FIG. 3 is a vertical cross-sectional view similar to FIG. 2, showing a modified example of this embodiment. [Figure 4] FIG. 4 is a perspective view showing a cover member according to this modified example. [Diagram 5] FIG. 5 is a vertical cross-sectional view of an expansion valve according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] (Direction definition) In this specification, the direction from the valve disc 3 to the actuating rod 5 is defined as the "upward direction," and the direction from the actuating rod 5 to the valve disc 3 is defined as the "downward direction." Therefore, in this specification, regardless of the attitude of the expansion valve 1, the direction from the valve disc 3 to the actuating rod 5 is called the "upward direction."

[0012] (First embodiment) An overview of an expansion valve 1 in this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic cross-sectional view showing an example in which the expansion valve 1 in this embodiment is applied to a refrigerant circulation system 100. Figure 2 is a vertical cross-sectional view showing an enlarged view of the periphery of a valve main body of this embodiment.

[0013] In this embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an evaporator 104. The axis of the expansion valve 1 is designated as L.

[0014] In FIG. 1, an expansion valve 1 includes a valve body 2 having a valve chamber VS, a valve element 3, a biasing device 4, an actuating rod 5, and a power element 8.

[0015] The valve body 2 includes a first flow path (also referred to as a high-pressure flow path) 21, a second flow path 22, an intermediate chamber 221, and a return flow path 23 in addition to the valve chamber VS. The first flow path 21 is a supply-side flow path, and a refrigerant (also referred to as a fluid) is supplied to the valve chamber VS via the supply-side flow path. The second flow path 22 is a discharge-side flow path (also referred to as an outlet-side flow path), and the fluid in the valve chamber VS is discharged to the outside of the expansion valve via the valve through hole 27, the intermediate chamber 221, and the discharge-side flow path. A pipe (not shown) connected to the inlet side of the evaporator 104 is connected to the second flow path 22.

[0016] The return flow passage 23 extends through the valve body 2 perpendicular to the axis L. The axis of the return flow passage 23 is O. The return flow passage 23 is composed of an inlet passage 23a to which a pipe (not shown) connected to the outlet side of the evaporator 104 is connected, an intermediate passage (also referred to as a low-pressure flow passage) 23b, a first enlarged diameter hole 23c having a larger diameter than the intermediate passage 23b, a second enlarged diameter hole 23d having a larger diameter than the first enlarged diameter hole 23c, and a third enlarged diameter hole 23e having a larger diameter than the second enlarged diameter hole 23d, which are coaxially connected to each other. The intermediate passage 23b is in communication with the lower space LS of the power element 8 via the vertical hole 2a, as will be described in detail later.

[0017] A double pipe 50 is connected to the return passage 23. The double pipe 50 has an inner pipe 51, the end of which fits into the intermediate passage 23b, and an outer pipe 52, which contains the inner pipe 51 and the end of which fits into the second enlarged diameter hole 23d. The inner pipe 51 has a flange portion 51a near the end of the inner pipe 51, which is formed by expanding a part of the pipe and crushing it in the axial direction. An O-ring OR1 held by the flange portion 51a is disposed between the end of the inner pipe 51 and the flange portion 51a, thereby sealing the gap between the first enlarged diameter hole 23c and the outer periphery of the inner pipe 51, preventing refrigerant leakage.

[0018] The outer pipe 52 also has a flange portion 52a near its end, which is formed by expanding a portion of the pipe and crushing it in the axial direction. The end of the outer pipe 52 does not bottom out on the step of the second enlarged diameter hole 23d, and the flange portion 52a abuts against the side surface of the valve body 2. An O-ring OR2 held by the flange portion 52a is disposed between the end of the outer pipe 52 and the flange portion 52a, thereby sealing the gap between the third enlarged diameter hole 23e and the outer periphery of the outer pipe 52 and preventing refrigerant leakage.

[0019] The inner pipe 51 is connected to the inlet of the compressor 101 , and the annular space between the outer pipe 52 and the inner pipe 51 (called an intermediate flow path) is connected to the outlet of the condenser 102 .

[0020] The first flow passage 21 has an axis (central axis) X1 (FIG. 2) in a plane including the axis L and the axis O, is inclined with respect to the axis L and the axis O, and its upper end opens to the inner circumference of the second enlarged diameter hole 23d. Meanwhile, the first flow passage 21 has a small diameter passage 21a, which is smaller in diameter than the first flow passage 21, coaxially at its lower end. This small diameter passage 21a is connected to the inner circumference of the valve chamber VS below the valve seat 20. That is, the inside of the second enlarged diameter hole 23d and the valve chamber VS are in communication with each other via the first flow passage 21. Referring to FIG. 2, when the small diameter passage 21a is projected onto the valve chamber VS along the axis X1 of the first flow passage 21, the projected image overlaps with the valve disc 3 and the valve disc support 42.

[0021] The valve chamber VS and the intermediate chamber 221 communicate with each other via the valve seat 20 and the valve through hole 27. The actuating rod insertion hole 28 formed above the intermediate chamber 221 has the function of guiding the actuating rod 5, and the annular recess 29 formed above the actuating rod insertion hole 28 has the function of accommodating the ring spring 6. The ring spring 6 applies a predetermined biasing force by abutting multiple spring pieces against the outer periphery of the actuating rod 5.

[0022] The valve disc 3 is disposed in the valve chamber VS. When the valve disc 3 is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the valve hole 27 is restricted. This state is called a non-communicating state. However, even when the valve disc 3 is seated on the valve seat 20, a restricted amount of refrigerant may flow. On the other hand, when the valve disc 3 is separated from the valve seat 20, the flow of refrigerant passing through the valve hole 27 increases. This state is called a communicating state.

[0023] The actuating rod 5 is inserted with a predetermined gap through the valve through hole 27. The lower end of the actuating rod 5 is in contact with the upper surface of the valve body 3. The upper end of the actuating rod 5 is fitted into a fitting hole at the lower end of the stopper member 84.

[0024] The actuating rod 5 can press the valve body 3 in the valve opening direction along the axis L against the biasing force of the biasing device 4. When the actuating rod 5 moves downward, the valve body 3 moves away from the valve seat 20, and the expansion valve 1 is opened.

[0025] The biasing device 4 has a coil spring 41 formed by winding a wire rod having a circular cross section in a spiral shape, a valve body support 42, and a spring receiving member 43.

[0026] The valve disc support 42 is attached to the upper end of the coil spring 41, and the spherical valve disc 3 is welded to its upper surface, forming a single unit. The valve disc 3 and the valve disc support 42 form a valve disc unit. However, the valve disc unit may be formed of only the valve disc 3. In that case, when the small diameter passage 21a is projected onto the valve chamber VS along the axis X1 of the first flow passage 21, the projected image will overlap only the valve disc 3. The axis of the valve disc unit refers to a straight line that includes the trajectory along which the center of gravity of the valve disc unit moves in response to the valve opening operation, and here coincides with the axis L of the expansion valve 1.

[0027] A spring receiving member 43 that supports the lower end of the coil spring 41 can be screwed into the valve body 2 and has the function of sealing the valve chamber VS and the function of adjusting the biasing force of the coil spring 41.

[0028] The power element 8 has a plug 81, an upper cover member 82, a diaphragm 83, a receiving member 86, and a stopper member 84.

[0029] The opening at the top of the generally conical top cover member 82 can be sealed with a plug 81 .

[0030] The diaphragm 83 is made of a thin metal (for example, SUS) plate material on which a plurality of concentric circular projections and recesses are formed, and has approximately the same outer diameter as the outer diameters of the upper cover member 82 and the receiving member 86.

[0031] The receiving member 86 is formed, for example, by press-molding a metal plate, and is configured by connecting a flange portion and a hollow cylindrical portion.

[0032] The stopper member 84 is disposed between the upper cover member 82 and the receiving member 86 , and its upper surface is in contact with the center of the lower surface of the diaphragm 83 .

[0033] In assembling the power element 8, the stopper member 84 is placed between the diaphragm 83 and the receiving member 86, while the outer peripheries of the upper cover member 82, the diaphragm 83, and the receiving member 86 are overlapped and the outer peripheries are circumferentially welded together by, for example, TIG welding, laser welding, plasma welding, etc.

[0034] Next, a working gas is injected into the space surrounded by the upper cover member 82 and the diaphragm 83 (called the pressure actuated chamber PO) through an opening formed in the upper cover member 82, and then the opening is sealed with a plug 81, and the plug 81 is fixed to the upper cover member 82 using projection welding or the like.

[0035] When the power element 8 assembled as described above is attached to the valve body 2, the male thread 86a on the outer periphery of the lower end of the hollow cylindrical portion of the receiving member 86 is screwed into the female thread 2b formed on the inner periphery of the vertical hole 2a that communicates with the return flow path 23 of the valve body 2. When the male thread 86a of the receiving member 86 is screwed into the female thread 2b, the lower surface of the flange portion of the receiving member 86 comes into contact with the upper end surface of the valve body 2. This allows the power element 8 to be fixed to the valve body 2.

[0036] At this time, a packing PK is interposed between the power element 8 and the valve body 2 to prevent leakage of the refrigerant when the power element 8 is attached to the valve body 2. In this state, the lower space LS of the power element 8 communicates with the return flow path 23 via the vertical hole 2a.

[0037] (Expansion valve operation) An example of the operation of the expansion valve 1 will be described with reference to FIG. 1. A high-pressure refrigerant pressurized by a compressor 101 is liquefied by a condenser 102 and sent to the expansion valve 1. The refrigerant adiabatically expanded by the expansion valve 1 is sent to an evaporator 104, where it is heat exchanged with air flowing around the evaporator. The refrigerant returning from the evaporator 104 enters the return flow path 23 of the expansion valve 1, and is returned to the compressor 101 side through the inner pipe 51 of the double pipe 50. At this time, the fluid pressure of the return flow path 23 becomes lower than the fluid pressure in the second flow path 22 by the refrigerant passing through the evaporator 104. The refrigerant that has passed through the evaporator 104 is called a low-pressure refrigerant.

[0038] A low-pressure refrigerant is sent from the expansion valve 1 to the compressor 101, and a high-pressure refrigerant is sent from the condenser 102 to the expansion valve 1. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to the valve chest VS via an intermediate flow path between the outer pipe 52 and the inner pipe 51 of the double pipe 50, and the first flow path 21.

[0039] When the valve element 3 is seated on the valve seat 20 (in a non-communicating state), the flow rate of the refrigerant sent from the valve chamber VS through the valve hole 27, the intermediate chamber 221, and the second flow path 22 to the evaporator 104 is restricted. On the other hand, when the valve element 3 is separated from the valve seat 20 (in a communicating state), the flow rate of the refrigerant sent from the valve chamber VS through the valve hole 27, the intermediate chamber 221, and the second flow path 22 to the evaporator 104 increases. The expansion valve 1 is switched between the closed state and the open state by the operating rod 5 connected to the power element 8 via the stopper member 84.

[0040] 1, a pressure actuated chamber PO and a lower space LS separated by a diaphragm 83 are provided inside the power element 8. Therefore, when the working gas in the pressure actuated chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, and the working rod 5 moves upward in response to the biasing force of the coil spring 41. On the other hand, when the liquefied working gas is vaporized, the diaphragm 83 and the stopper member 84 are pressed downward, and the working rod 5 moves downward. In this way, the expansion valve 1 is switched between the open state and the closed state.

[0041] Furthermore, the lower space LS of the power element 8 communicates with the return flow passage 23 via the vertical hole 2a. Therefore, the volume of the working gas in the pressure actuated chamber PO changes depending on the temperature and pressure of the refrigerant flowing through the return flow passage 23, and the actuating rod 5 is driven. In other words, in the expansion valve 1 shown in FIG. 1, the amount of refrigerant supplied from the expansion valve 1 to the evaporator 104 is automatically adjusted depending on the temperature and pressure of the refrigerant returning from the evaporator 104 to the expansion valve 1.

[0042] However, if the time constant of the power element 8 is relatively small, a hunting phenomenon is likely to occur, which may cause vibration of the valve element 3. In contrast, according to this embodiment, the axis X1 of the first flow passage 21 is a straight line, and the valve element 3 or the valve element support 42 is arranged on an extension of the axis X1, or when the small path 21a is projected along the axis X1 of the first flow passage 21 toward the valve chamber VS, the projected image overlaps the valve element 3 or the valve element support 42. Therefore, as shown by the arrow in FIG. 2, the refrigerant flowing out from the small path 21a to the valve chamber VS when the valve is opened hits the valve element 3 or the valve element support 42 from an oblique direction (i.e., a direction inclined with respect to the axis L), and the valve element 3 is given resistance by the fluid, thereby suppressing vibration. In particular, when the valve element 3 vibrates vertically, the refrigerant hits it obliquely, which can give resistance to the valve element 3 when it moves upward, thereby achieving a high vibration suppression effect.

[0043] In addition, since a small diameter passage 21a having a smaller diameter than the first flow passage 21 other than the small diameter passage 21a is arranged at the refrigerant outlet of the first flow passage 21, the outflow speed of the refrigerant is increased by the throttling effect of the small diameter passage 21a, and the vibration of the valve body 3 can be further effectively suppressed.

[0044] (Modification) Fig. 3 is a vertical cross-sectional view similar to Fig. 2, showing a modification of this embodiment. Fig. 4 is a perspective view showing a cover member 60 according to this modification. Other configurations are the same as those in the above-mentioned embodiment, so the same reference numerals are used and repeated explanations will be omitted.

[0045] In this modified example, a cover member 60 is disposed between the valve body support 42 and the coil spring 41. As shown in Fig. 4, the cover member 60 has a cylindrical shape with a top, with a peripheral wall 61 and a top wall 62 connected together, and a circular opening 63 is formed in the center of the top wall 62. The cover member 60 can be formed by press molding a metal plate material.

[0046] The valve body support 42 has a cylindrical main body 42a and a flange portion 42b extending radially outward from the main body 42a. When the cover member 60 is placed over the top of the coil spring 41, the lower surface of the top wall 62 comes into contact with the upper end of the coil spring 41, and the upper periphery of the coil spring 41 is surrounded by the peripheral wall 61. The valve body support 42 is then brought closer from above the cover member 60, and the main body 42a is fitted into the circular opening 63 and the inner periphery of the upper end of the coil spring 41, thereby completing the assembly. The top wall 62 of the cover member 60 is sandwiched and held between the upper end of the coil spring 41 and the flange portion 42b of the valve body support 42.

[0047] According to this modified example, as shown in FIG. 3, the upper part of the coil spring 41 is covered by the cover member 60, so that the refrigerant flowing from the small path 21a toward the valve chamber VS flows along the smooth surface of the cover member 60. This suppresses the generation of turbulence, enhances the vibration damping effect of the valve body 3, and suppresses the generation of abnormal noise.

[0048] Second embodiment 3 is a vertical cross-sectional view of an expansion valve 1A according to the second embodiment. This embodiment differs from the first embodiment only in the shape of the first flow passage 21A of the valve body 2A. The other configurations are the same as those of the above-mentioned embodiments, so the same reference numerals are used and repeated explanations are omitted. In this embodiment, the first flow passage 21A other than the small diameter passage 21Aa constitutes the first passage, and the small diameter passage 21Aa constitutes the second passage.

[0049] In the first flow passage 21A of this embodiment, the axis X2 of the small diameter passage 21Aa intersects with the axis X1 of the first flow passage 21A other than the small diameter passage 21Aa. More specifically, the crossing angle θ2 between the axis X2 of the small diameter passage 21Aa and the axis L is smaller than the crossing angle θ1 between the axis X1 of the first flow passage 21A other than the small diameter passage 21Aa and the axis L. According to this embodiment, when the small diameter passage 21Aa is projected onto the valve chamber VS along the axis X2, the projected image overlaps with the valve body support 42. The crossing angles θ1 and θ2 can be arbitrarily changed according to the specifications of the expansion valve 1A. Therefore, the crossing angle θ1 may be smaller than the crossing angle θ2.

[0050] The axis X1 of the first flow passage 21A other than the small diameter passage 21Aa does not intersect with the inner circumference of the return flow passage 23, and the axis X2 of the small diameter passage 21Aa does not intersect with the inner circumference of the valve chamber VS. Therefore, by inserting a tool such as a drill obliquely with respect to the axis O, i.e., along the axis X1, into the return flow passage 23 from the outside of the third enlarged diameter hole 23e, it is possible to cut the first flow passage 21A other than the small diameter passage 21Aa. On the other hand, by inserting a tool such as a drill obliquely with respect to the axis L, i.e., along the axis X2, from below the opening that forms the valve chamber VS, it is possible to cut the small diameter passage 21Aa so as to be connected to the first flow passage 21A.

[0051] According to this embodiment, when the valve is open, the refrigerant flowing out from the small diameter passage 21Aa to the valve chamber VS hits the valve element support 42 from an oblique direction, thereby suppressing vibration of the valve element 3. When suppressing vibration of the valve element 3, there are cases where hitting the refrigerant against the valve element support 42 rather than against the valve element 3 provides a higher vibration suppression effect. Therefore, by arbitrarily angling the small diameter passage 21Aa of the first flow path 21A, it is possible to direct the refrigerant to the optimal position.

[0052] It should be noted that the present invention is not limited to the above-described embodiment. Any of the components of the above-described embodiment may be modified within the scope of the present invention. Any of the components of the above-described embodiment may be added or omitted. [Explanation of symbols]

[0053] 1, 1A: Expansion valve 2, 2A: Valve body 3: Valve body 4: Actuating device 5: Operating rod 6: Ring spring 8: Power Element 20: Valve seat 21, 21A: First flow path 22: Second flow path 23: Return flow path 27: Valve hole 41: Coil spring 42: Valve body support 43: Spring support member 50: Double piping 60: Cover member 100: Refrigerant circulation system 101: Compressor 102: Capacitor 104: Evaporator VS: Valve chamber

Claims

1. An expansion valve capable of connecting a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes through an intermediate flow passage that is a space between an outer pipe arranged around the inner pipe and the inner pipe, a valve body including a valve chamber having a valve seat, a valve through hole as a throttle connecting the valve chamber with a downstream side of the valve chamber, and a high-pressure flow passage connected from the intermediate flow passage to the valve chamber and through which a high-pressure refrigerant flows; a valve body unit including a valve body that can be seated on the valve seat, a valve body support including a main body that supports the valve body and a flange portion formed on the main body; an actuating rod disposed in the valve through hole and in contact with the valve body; A power element that drives the actuation rod; a coil spring disposed on the opposite side of the actuation rod from the power element and biasing the valve body unit toward the power element via the flange portion of the valve body support; the high-pressure flow passage is formed at an angle with respect to an axis of the valve body unit so that the high-pressure refrigerant that has flowed through the high-pressure flow passage from the intermediate flow passage toward the valve chamber hits the flange portion of the valve body support, When the high pressure flow passage is projected along an axis of the high pressure flow passage, the projected image overlaps with the flange portion of the valve body support in a valve closed state. An expansion valve characterized by:

2. A cover member having a top wall disposed between the flange portion of the valve body support and the coil spring, and a peripheral wall surrounding at least a portion of the periphery of the coil spring.

2. The expansion valve according to claim 1 .

3. the high pressure flow passage has a first passage on the outer pipe side and a second passage on the valve chamber side, the first passage having an inner diameter larger than an inner diameter of the second passage, When the second passage is projected along an axis of the second passage, the projected image overlaps with the flange portion of the valve body support in a valve closed state.

3. The expansion valve according to claim 1 or 2.

4. The axis of the first passage and the axis of the second passage intersect.

4. The expansion valve according to claim 3.

Images