Expansion valve

Abstract

To provide an expansion valve that can be used over a wide temperature range and that allows for adjustment of the biasing force by the coil spring. [Solution] The hole 11 of the valve body 10 of the expansion valve 1 has a cylindrical portion 11b into which an adjustment screw 42 is screwed, and a female tapered portion 11c having a conical surface that decreases in diameter towards the orifice 13. The adjustment screw 42 has a cap portion 43 that is screwed into the cylindrical portion 11b, and a male tapered portion 44c having a conical surface that decreases in diameter towards the orifice 13. The taper angle of the male tapered portion 44c is smaller than the taper angle of the female tapered portion 11c. The sealing member 50 is annular and is plastically deformed by being sandwiched between the female tapered portion 11c and the male tapered portion 44c. The area of ​​the outer circumferential surface of the sealing member 50 facing the female tapered portion 11c has a shape that follows the shape of the female tapered portion 11c, and the area of ​​the inner circumferential surface of the sealing member 50 facing the male tapered portion 44c has a shape that follows the shape of the male tapered portion 44c.

Description

Technical Field

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

Background Art

[0002] Conventionally, as an expansion valve used in a refrigeration cycle for air conditioning, a configuration is known that includes a valve body in which a valve chamber is formed, a valve element disposed in the valve chamber, a coil spring that biases the valve element in the valve closing direction, and a power element that biases the valve element in the valve opening direction according to the refrigerant flowing downstream of the evaporator.

[0003] In this type of expansion valve, an opening for installing components such as a valve element and a coil spring is formed in the valve body, and this opening is disposed on the side of the valve body opposite to the orifice. The opening is closed by an adjusting screw that supports the coil spring, and the adjusting screw can adjust its relative position with the valve body by being in a screwing relationship with a hole. By adjusting the position of the adjusting screw with respect to the valve body, the deflection amount of the coil spring at the time of valve closing, that is, the biasing force of the valve element by the coil spring, is adjusted.

[0004] Such an adjusting screw has a male screw portion that screws into an internal thread formed on the inner peripheral surface of the hole of the valve body, and a cylindrical portion that is continuously provided on the male screw portion and in which a coil spring is disposed inside. Further, an O-ring is provided between the inner peripheral surface of the valve chamber and the cylindrical portion of the adjusting screw (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In expansion valves using the aforementioned O-rings, the usable temperature range is affected by the O-ring. In other words, the usable temperature range of the expansion valve is limited to the temperature range in which the O-ring can maintain its sealing performance.

[0007] On the other hand, expansion valves are also required to be used in temperature ranges where the effectiveness of O-rings would be affected. To address this requirement, it is conceivable to use a metal sealing component instead of a rubber O-ring.

[0008] When using a metal sealing member, it is necessary to compress the sealing member between the adjustment screw and the inner surface of the hole in the valve body by a predetermined amount to improve the degree of contact between the sealing member and both the adjustment screw and the inner surface of the hole. However, because the metal sealing member is compressed and crushed by a predetermined amount between the inner surface of the hole and the adjustment screw, a problem arises in that the adjustment range of the biasing force of the valve body by the coil spring becomes small.

[0009] To explain this issue, the adjustment range of a coil spring is the amount by which the metal seal can be compressed. However, the metal seal member is already compressed to a certain extent in order to achieve a seal. Therefore, when adjusting the biasing force of the coil spring, the adjustment is made by compressing it further from this already compressed state, resulting in a small adjustment range.

[0010] The present invention aims to provide an expansion valve that can be used over a wide temperature range and that allows for adjustment of the biasing force of the valve body by a coil spring. [Means for solving the problem]

[0011] The expansion valve of the present invention comprises a valve body, an adjustment screw, a valve element, a coil spring, and a sealing member. The valve body has a hole extending longitudinally with an opening on its outer surface, and an orifice formed on the side of the hole opposite the opening in the longitudinal direction. The adjustment screw is disposed within the hole and is a bottomed cylindrical shape with a bottom on the opening side. The adjustment screw's outer surface is screwed into the inner surface of the hole, allowing its relative position to the valve body in the longitudinal direction to be adjusted, and it forms a valve chamber between itself and the inner surface of the hole. The valve element is disposed within the valve chamber. The coil spring is disposed between the valve element and the adjustment screw, with a portion of it disposed within the adjustment screw, and biases the valve element toward the orifice. The sealing member is annular and provided between the adjustment screw and the inner surface of the hole.

[0012] The inner circumferential surface of the hole has a female threaded portion into which the adjustment screw is screwed, and a female tapered portion formed on the orifice side relative to the female threaded portion and having a conical surface that decreases in diameter towards the orifice side. The outer circumferential surface of the adjustment screw has a male threaded portion that is screwed into the female threaded portion, and a male tapered portion formed on the orifice side relative to the male threaded portion and having a conical surface that decreases in diameter towards the orifice side. The taper angle of the male tapered portion is smaller than the taper angle of the female tapered portion. The sealing member is in a state of plastic deformation due to compression between the female tapered portion and the male tapered portion, and the area of ​​the outer circumferential surface of the sealing member facing the female tapered portion has a shape that conforms to the female tapered portion, and the area of ​​the inner circumferential surface of the sealing member facing the male tapered portion has a shape that conforms to the male tapered portion. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an expansion valve that can be used over a wide temperature range and that can ensure adjustment range for the biasing force of the valve body by a coil spring. [Brief explanation of the drawing]

[0014] [Figure 1]A cross-sectional view showing an expansion valve according to the first embodiment of the present invention. [Figure 2] A cross-sectional view showing a magnified view of the main part of the expansion valve. [Figure 3] A cross-sectional view showing part of the assembly process for the expansion valve. [Figure 4] A cross-sectional view showing part of the assembly process for the expansion valve. [Figure 5] A cross-sectional view showing an enlarged view of the main part of the expansion valve according to the second embodiment of the present invention. [Figure 6] A cross-sectional view showing an enlarged view of the main part of an expansion valve according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0015] [First Embodiment] An expansion valve 1 according to the first embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a cross-sectional view showing the expansion valve 1. Figure 2 is a cross-sectional view showing an enlarged view of the opening 11a and its surroundings of the valve body 10 of the expansion valve 1, which will be described later. Figure 3 is a cross-sectional view showing part of the manufacturing process of the expansion valve 1. Figure 4 is a cross-sectional view showing part of the manufacturing process of the expansion valve 1.

[0016] As shown in Figure 1, the expansion valve 1 comprises a valve body 10, a valve element 20, a valve element support member 30, a biasing device 40, a sealing member 50, a power element 60, and an operating rod 70. The expansion valve 1 is part of a refrigeration cycle used, for example, in a vehicle, and has a portion of the flow path between the condenser and the evaporator of the refrigeration cycle, and a portion of the flow path between the evaporator and the compressor of the refrigeration cycle.

[0017] For the sake of explanation, the direction from the valve body 20 toward the orifice 13 (described later) is defined as the upward direction, and the vertical direction is defined as that direction. A straight line perpendicular to the vertical direction is defined as the width direction. Figures 1 to 4 show the state when the orifice 13 is cut along a cross section that passes through its center and is parallel to both the vertical and width directions. Furthermore, the coaxial structure in this embodiment includes both strictly coaxial structures and substantially coaxial structures that include errors due to manufacturing tolerances, etc.

[0018] As shown in FIG. 1, the valve body 10 has a hole 11, a valve chamber 12, an orifice 13, an inflow passage 14, an outflow passage 15, and a return flow passage 16. The material of the valve body 10 is, for example, stainless steel and has a vertically long shape.

[0019] The hole 11 extends from a position below, for example, the middle part in the vertical direction inside the valve body 10 to the lower end. That is, the hole 11 extends in the longitudinal direction of the valve body 10. The inner peripheral surface of the hole 11 is a cylindrical surface whose cross-sectional shape perpendicular to the axis of the inner peripheral surface is a circle. The lower end opening of the hole 11 is closed by an adjustment screw 42 described later. The part of the hole 11 other than the adjustment screw 42 becomes the valve chamber 12. In the present embodiment, the lower end opening of the hole 11 and the range in its vicinity are referred to as an opening 11a.

[0020] The opening 11a has a cylindrical part 11b which is the lower part of the opening 11a divided in the vertical direction and a female tapered part 11c which is the upper part.

[0021] The cylindrical part 11b is a cylindrical hole. A female thread 11d is formed on the inner peripheral surface of the cylindrical part 11b, and the adjustment screw 42 described later can be screwed into it. That is, the cylindrical part 11b is an example of the female thread part referred to in the present invention. In the present embodiment, the female thread 11d is not arranged at the upper end of the cylindrical part 11b and its periphery. The upper end of the cylindrical part 11b and its periphery constitute a part of the accommodating part 11e. The accommodating part 11e is a space part formed between the inner peripheral surface of the cylindrical part 11b and the adjustment screw 42, and the lower end part of the seal member 50 can be arranged therein.

[0022] The female tapered part 11c is coaxial with the cylindrical part 11b. The female tapered part 11c has a conical surface centered on the axis X of the hole 11, that is, the axis, which tapers in diameter toward the orifice 13 side. The diameter of the lower end of the female tapered part 11c is smaller than the diameter of the upper end of the cylindrical part 11b. The female tapered part 11c and the upper end of the cylindrical part 11b are continuous via the upper surface 11f of the cylindrical part 11b. The upper surface 11f is, for example, a plane perpendicular to the axis of the hole 11.

[0023] The orifice 13 is formed at the top of the hole 11. The orifice 13 is positioned coaxially with the hole 11. Downstream of the orifice 13, a throat 17 is formed that is continuous with the orifice. The throat 17 is positioned coaxially with the orifice 13. The area around the orifice 13 constitutes a valve seat on which the valve body 20 is seated. The throat 17 is a cylindrical hole with the same diameter as the orifice 13.

[0024] The inlet passage 14 is formed in the lower part of the valve body 10 and extends in the width direction. The inlet passage 14 is a passage that allows refrigerant to flow into the valve chamber 12. The outlet passage 15 is formed below the middle of the valve body 10 in the vertical direction and extends in the width direction. The outlet passage 15 is a passage that allows refrigerant that has passed through the orifice 13 to flow out of the valve body 10. The outlet passage 15 includes a throat 17. The return passage 16 is formed in the upper part of the valve body 10 and extends in the width direction. The return passage 16 is a passage that allows refrigerant that has passed through the evaporator to flow and is part of the passage that connects the evaporator and the compressor.

[0025] The valve body 20 is, for example, spherical and is located in the valve chamber 12. The valve support member 30 has a main body 31 that supports the valve body 20 and a flange portion 32 that abuts against a coil spring 41, which will be described later. The main body 31 is columnar in shape, for example, cylindrical, and elongated in the vertical direction. The valve body 20 is fixed to the upper surface of the main body 31, for example. The fixing means for fixing the valve body 20 to the main body 31 is, for example, welding or adhesive. In other examples, the valve body 20 does not have to be fixed to the main body 31 by a fixing means. A part of the main body 31 is arranged inside the coil spring 41. The flange portion 32 is formed on the upper part of the outer circumferential surface of the main body 31, for example, and is annular in shape, for example, circular, and extends in a direction perpendicular to the axis of the main body 31.

[0026] The biasing device 40 has the function of biasing the valve body 20 toward the orifice 13 and comprises a coil spring 41 and an adjustment screw 42. As shown in Figure 2, the adjustment screw 42 has a cover portion 43 that screws onto the first cylindrical portion 11b of the hole 11 and a support portion 44 connected to the cover portion 43 that supports the coil spring 41. The material of the adjustment screw 42 is, for example, stainless steel.

[0027] The cover portion 43 is cylindrical, and a male thread 43a is formed on its outer circumferential surface. The cover portion 43 is an example of a male thread portion as defined in this invention. By screwing the male thread 43a into the female thread 11d of the opening 11a, the adjustment screw 42 can be adjusted in its relative position to the valve body 10 in the vertical direction. When the adjustment screw 42 is fixed to the opening 11a, it is coaxial with the opening 11a.

[0028] The support portion 44 is formed on the valve chamber 12 side of the lid portion 43. The support portion 44 is cylindrical in shape, and at least the lower part of the coil spring 41 is positioned thereon, and is coaxial with the lid portion 43. The support portion 44 is aligned vertically with the female tapered portion 11c of the opening 11a.

[0029] The support portion 44 has a conical surface that sandwiches the sealing member 50, which will be described later, between itself and the female tapered portion 11c of the opening 11a. In this embodiment, the support portion 44 has a cylindrical portion 44b that is continuous with the base portion 43 and a male tapered portion 44c that is positioned above the cylindrical portion 44b. The outer circumferential surface of the male tapered portion 44c is a conical surface with axis X as its axis. The vertical length of the male tapered portion 44c is longer than the vertical length of the cylindrical portion 44b. The end face of the male tapered portion 44c is, for example, a plane perpendicular to the vertical direction.

[0030] If the taper angle of the female tapered portion 11c is α and the taper angle of the male tapered portion 44c of the adjustment screw 42 is β, then α > β. The taper angle of the female tapered portion 11c is the angle between the axis X and the extension of the conical surface of the female tapered portion 11c in a cross section passing through and parallel to the axis X, as shown in Figure 2. The taper angle of the male tapered portion 44c is the angle between the axis X and the extension of the male tapered portion 44c in a cross section passing through and parallel to the axis X. When the adjustment screw 42 is fixed to the opening 11a, it becomes coaxial with the axis X. For this reason, the taper angle of the male tapered portion 44c with respect to the axis of the adjustment screw 42 is also β.

[0031] The cylindrical portion 44b is spaced apart from the upper end of the cylindrical portion 11b of the valve body 10 (the portion where the female thread 11d is not formed), and a housing portion 11e is formed between it and the upper end of the cylindrical portion 11b, in which a part of the sealing member 50 can be placed. The housing portion 11e is an annular space that is continuous around the adjustment screw 42. The upper end of the cylindrical portion 11b is a portion that is continuous with the female tapered portion 11c, and is an example of the first part of the present invention. The cylindrical portion 44b of the adjustment screw 42 is a portion that is continuous with the male thread 43a, and is an example of the second part of the present invention.

[0032] As shown in Figure 1, the coil spring 41 is positioned within the support portion 44, and its upper end abuts against the lower surface of the flange portion 32 of the valve body support member 30, biasing the valve body 20 toward the orifice 13 via the valve body support member 30.

[0033] As shown in Figure 2, the sealing member 50 is provided between the female tapered portion 11c and the male tapered portion 44c. The sealing member 50 is a frustoconical cylindrical shape. The inner and outer circumferential surfaces of the sealing member 50 are conical surfaces. The sealing member 50 is made of a metal that is more easily deformable than both the female tapered portion 11c and the male tapered portion 44c, for example, copper. That is, the sealing member 50 is made of a metal that is more easily deformable than both the material of the valve body 10 having the female tapered portion 11c and the material of the adjustment screw 42 having the male tapered portion 44c. Here, a metal material that is easily deformable is a metal material in which, when the sealing member 50 is sandwiched between the female tapered portion 11c and the male tapered portion 44c and the adjustment screw 42 is screwed in, the sealing member 50 is compressed between the female tapered portion 11c and the male tapered portion 44c without deformation of either the female tapered portion 11c or the male tapered portion 44c, and the sealing member 50 is crushed in the compression direction and undergoes plastic deformation.

[0034] Because the sealing member 50 is more easily deformed by both the valve body 10 and the adjustment screw 42, as described later, when the adjustment screw 42 is screwed into the valve body 10, the sealing member 50 is compressed and crushed between the female tapered portion 11c and the male tapered portion 44c, causing plastic deformation. When the sealing member 50 is assembled to the expansion valve 1, it is compressed and crushed between the female tapered portion 11c and the male tapered portion 44c, causing plastic deformation. The area of ​​the outer circumferential surface of the sealing member 50 facing the female tapered portion 11c takes on a shape that conforms to the female tapered portion 11c. The area of ​​the inner circumferential surface of the sealing member 50 facing the male tapered portion 44c takes on a shape that conforms to the male tapered portion 44c. In this embodiment, the sealing member 50 is deformed into a shape that closely conforms to the female tapered portion 11c and the male tapered portion 44c. In other words, the portion of the sealing member 50 facing the female tapered portion 11c is in surface contact with the female tapered portion 11c, and the portion of the sealing member 50 facing the male tapered portion 44c is in surface contact with the male tapered portion 44c. The sealing member 50 is compressed and crushed between the female tapered portion 11c and the male tapered portion 44c, causing its lower end to extend downward and be housed in the housing portion 11e. The fact that the portion of the outer circumferential surface of the sealing member 50 facing the female tapered portion 11c is in close contact with the female tapered portion 11c is an example of the sealing member 50 conforming to the shape of the female tapered portion 11c. The fact that the portion of the inner circumferential surface of the sealing member 50 facing the male tapered portion 44c is in close contact with the male tapered portion 44c is another example of the sealing member 50 conforming to the shape of the male tapered portion 44c.

[0035] As shown in Figure 1, the power element 60 is fixed to the upper surface of the valve body 10. The power element 60 generates a driving force that displaces the valve body 20 in the opening direction. The power element 60 comprises a housing 61 fixed to the valve body 10, a diaphragm 62 provided inside the housing 61, and a stopper member 63 that restricts the deformation of the diaphragm 62.

[0036] The housing 61 has an opening at its lower end that communicates with the return passage 16. The diaphragm 62 is located inside the housing 61 and divides the inside of the housing 61 into upper and lower sections. As a result, the housing 61 is configured with an upper pressure-operated chamber 64 and a lower communication chamber 65. The pressure-operated chamber 64 is filled with working fluid. The communication chamber 65 communicates with the return passage 16.

[0037] The stopper member 63 is positioned within the communication chamber 65, and its upper part is in contact with the diaphragm 62. When the diaphragm 62 undergoes a displacement that causes it to bulge downward, the stopper member 63 is displaced downward in response to this displacement. The stopper member 63 has a flange, and this flange contacts the housing 61, thereby restricting the stopper member 63 from moving downward beyond a predetermined position. By restricting the downward movement of the stopper member 63, the deformation of the diaphragm 62 is restricted.

[0038] The operating rod 70 is provided between the stopper member 63 and the valve body 20, and transmits the driving force generated by the power element 60 to the valve body 20. The operating rod 70 has a straight rod shape that extends in the vertical direction. The upper end of the operating rod 70 is fixed to the stopper member 63.

[0039] Next, we will describe the state of the sealing member 50 before installation and provide an example of the installation procedure for the adjustment screw 42 to the valve body 10.

[0040] First, the state of the seal member 50 before installation will be explained using Figure 3. Figure 3 shows part of the process of fixing the adjustment screw 42 to the valve body 10. Specifically, it shows the state after the adjustment screw 42 has been screwed into the valve body 10, up to the point where the seal member 50 contacts the female tapered portion 11c of the opening 11a and the male tapered portion 44c of the adjustment screw 42. In the state shown in Figure 3, the seal member 50 has not undergone any compressive deformation between the female tapered portion 11c and the male tapered portion 44c. That is, the seal member 50 shown in Figure 3 is in the same state as before it is assembled to the expansion valve 1. In the state before it is attached to the expansion valve 1, the seal member 50 has a constant thickness from the top end to the bottom end, and the taper angle of its inner and outer surfaces with respect to the axis X is the same as, for example, the taper angle α of the female tapered portion 11c with respect to the axis X.

[0041] Next, the procedure for attaching the adjustment screw 42 to the valve body 10 will be described. First, the worker places the sealing member 50 inside the opening 11a, as shown in Figure 3. In order to place the sealing member 50 inside the opening 11a, the worker performs an attachment process in which the valve body 10, the coil spring 41, and the sealing member 50 are attached to the adjustment screw 42, which is separated from the hole 11 of the valve body 10, and an insertion process in which the adjustment screw 42, with the coil spring 41 and sealing member 50 attached in the attachment process, is inserted into the hole 11 of the valve body 10.

[0042] To explain the installation process, in this embodiment, as an example, the first to fourth steps described below are performed. First step: The sealing member 50, before it is compressed between the female tapered portion 11c and the male tapered portion 44c, is attached to the male tapered portion 44c of the adjustment screw 42. Second step: Insert the coil spring 41 into the adjustment screw 42. Third step: Attach the valve support member 30 to the tip of the coil spring 41. Step 4: Place the valve body 20 on the valve body support member 30.

[0043] The order in which these first to fourth steps are performed is not limited. For example, the order may be the first step, the second step, the third step, and the fourth step, or the second step, the first step, the third step, and the fourth step.

[0044] In this embodiment, as an example, the valve body 20 is supported by the coil spring 41 via the valve body support member 30. For example, if the expansion valve 1 is configured not to have a valve body support member 30, the third and fourth steps described above are replaced by the step of supporting the valve body 20 on the coil spring 41. Also, if the valve body 20 is fixed to the valve body support member 30 by fixing means, the third and fourth steps described above are replaced by the step of attaching the integrated valve body 20 and valve body support member 30 to the tip of the coil spring 41.

[0045] These first, second, third, and fourth steps are examples of mounting steps in a manufacturing method for the expansion valve 1, in which a coil spring 41 is installed in an adjustment screw 42 that is separated from the valve body 10, the valve body 20 is supported by the coil spring 41, and a sealing member 50 is attached to the male tapered portion 44c of the adjustment screw 42. As described above, this mounting step is appropriately determined according to the configuration of the expansion valve 1.

[0046] Once the above-described mounting and insertion processes are complete, the operator then screws the adjustment screw 42 into the valve body 10 until it contacts the seal member 50. In this state, the seal member 50 is held between the female tapered portion 11c and the male tapered portion 44c, but it is not crushed (compressed).

[0047] Next, the operator further screws in the adjustment screw 42 to achieve a seal by the sealing member 50 (sealing process). The amount by which the adjustment screw 42 is screwed in is the amount by which it is displaced by a predetermined amount towards the orifice 13 side (upward side) along the axis of the hole 11. Here, the predetermined amount will be explained. In order for the sealing member 50 to seal between the valve body 10 and the adjustment screw 42, it is necessary for the sealing member 50 to be crushed and plastically deformed between the female tapered portion 11c and the male tapered portion 44c so that it is in close contact with the female tapered portion 11c and the male tapered portion 44c.

[0048] The predetermined amount is set in advance to an amount that causes plastic deformation in the sealing member 50 and ensures the required sealing performance of the expansion valve 1. Figure 4 shows the state in which the adjustment screw 42 has been screwed in by a predetermined amount from the state shown in Figure 3. In this embodiment, the predetermined amount is 0.5 mm. As shown in Figure 4, the initial state is when the adjustment screw 42 has been screwed in by a predetermined amount, i.e., when a seal has been achieved.

[0049] In the initial state, as shown in Figure 2, the taper angle of the surface 51 of the seal member 50 on the side of the female tapered portion 11c with respect to the axis X is the same as the taper angle α of the inner surface of the female tapered portion 111c with respect to the axis X. Similarly, when the adjustment work of the coil spring 41 is completed, the taper angle of the surface 52 of the seal member 50 on the side of the adjustment screw 42 with respect to the axis X is the same as the taper angle β of the male tapered portion 44c with respect to the axis X.

[0050] As shown in Figure 4, once the adjustment screw 42 is screwed in to its initial state, the operator then further screws the adjustment screw 42 from the initial state to adjust the biasing force of the valve body 20 by the coil spring 41 (adjustment step). In this embodiment, as an example, as shown in Figure 2, the adjustment screw 42 is further displaced by 0.5 mm towards the orifice 13 along the axis of the opening 11a from the initial state. The seal member 50 is further compressed and crushed between the female tapered portion 11c and the male tapered portion 44c as the adjustment screw 42 is further screwed in from the initial state.

[0051] The distance between the female tapered portion 11c and the male tapered portion 44c increases from the top end downwards because the taper angle β of the male tapered portion 44c is smaller than the taper angle α of the female tapered portion 11c. For this reason, when the sealing member 50 is compressed and crushed between the female tapered portion 11c and the male tapered portion 44c, its lower end is prone to deforming in such a way that it extends downwards.

[0052] Next, a part of the operation of the expansion valve 1 will be described. The temperature and pressure of the refrigerant in the communication chamber 65 of the power element 60 are transmitted to the diaphragm 62 directly or via the stopper member 63. The working fluid in the pressure working chamber 64 undergoes a volume change in response to the temperature and pressure of the refrigerant received through the diaphragm 62. The diaphragm 62 deforms in response to this volume change, and the valve body 20 is displaced between the closed state and the fully open state as a result of this deformation.

[0053] Next, the effects obtained in this embodiment will be described. In this embodiment, it is possible to increase the adjustment range of the length of the coil spring 41 from the initial state. In explaining this effect, for comparison, we will consider an expansion valve in which the taper angle of the female tapered portion 11c with respect to the axis X is α, and the taper angle of the male tapered portion 44c with respect to the axis X is also α. The other configurations of this expansion valve are the same as those of expansion valve 1.

[0054] In this embodiment, since β < α, the deformation of the seal member 50 caused by screwing the adjustment screw 42 in by one pitch is smaller than the deformation of the seal member 50 caused by screwing the adjustment screw 42 in by one pitch in an expansion valve where α = β. In this embodiment, since the deformation of the seal member 50 with respect to the screwing amount of the adjustment screw 42 is smaller in the expansion valve where α = β, the displacement length along the axis X of the adjustment screw 42 from the initial state to the limit in which the seal member 50 can be compressed can be made longer compared to the expansion valve where α = β. In other words, the adjustment range of the coil spring 41 from the initial state can be made longer.

[0055] Furthermore, the opening 11a of the expansion valve 1 is provided with a housing portion 11e at the upper end and around the first cylindrical portion 11b. The housing portion 11e is adjacent to the female tapered portion 11c. Therefore, when the seal member 50 is compressed between the female tapered portion 11c and the male tapered portion 44c, a part of the seal member 50 can deform so as to enter the housing portion 11e, making the seal member 50 more easily deformable. As a result, it becomes possible to ensure adjustment range for the biasing force of the valve body 20 by the coil spring 41. Thus, with the expansion valve 1 of this embodiment, since the sealing member 50 is made of metal, it can be used in a wide temperature range, and furthermore, as described above, it is possible to secure adjustment range for the valve body 20 by the coil spring 41.

[0056] [Second Embodiment] In the first embodiment, the female tapered portion 11c, which is a conical surface that clamps the sealing member 50 between the opening 11a and the adjustment screw 42, has one taper angle with respect to the axis X. In other examples, the female tapered portion 11c may have two or more conical surfaces with different taper angles.

[0057] As an example, a female tapered portion 11c having two conical surfaces with different taper angles with respect to the axis X will be described as a second embodiment using Figure 5. Components having the same function as in the first embodiment will be given the same reference numerals as in the first embodiment and their description will be omitted. In the case of the expansion valve 1 of the second embodiment, only the female tapered portion 11c differs from the conical portion 11c of the first embodiment, so the opening 11a will be described. Figure 5 is an enlarged cross-sectional view showing the opening 11a and its surroundings of the expansion valve 1 of this embodiment. Figure 5 shows a state in which the orifice 13 has been cut along a cross section that passes through the center of the orifice 13 and is parallel to the vertical and width directions.

[0058] As shown in Figure 5, the opening 11a of this embodiment has a first cylindrical portion 11b and a female tapered portion 11c. The female tapered portion 11c has a first conical surface 11c1 and a second conical surface 11c2. The first conical surface 11c1 is the portion of the female tapered portion 11c in the vertical direction, for example, from the middle to the upper end, and is a conical surface with axis X as its axis and a taper angle of α with respect to axis X. The second conical surface 11c2 is the portion of the female tapered portion 11c in the vertical direction, for example, from the middle to the lower end, and is a conical surface with axis X as its axis and a taper angle of Γ with respect to axis X such that α < Γ. Even in this embodiment, the same operation and effects as in the first embodiment can be obtained.

[0059] In other examples of this embodiment, the female tapered portion 11c may have three or more conical surfaces. Even in this case, the taper angle of each conical surface with respect to the axis X is greater than the taper angle of the outer circumferential surface of the conical portion of the adjustment screw 42 with respect to the axis X.

[0060] [Third Embodiment] Next, an expansion valve according to a third embodiment of the present invention will be described with reference to Figure 6. In the first and second embodiments, the male tapered portion 44c of the adjustment screw 42, which sandwiches the sealing member 50 between itself and the inner circumferential surface of the hole 11, is a conical surface having one taper angle with respect to the axis X. In other examples, the male tapered portion 44c may have two or more conical surfaces having different taper angles with respect to the axis X.

[0061] This example will be explained using Figure 6 as a third embodiment. In this embodiment, components having the same function as in the first embodiment are denoted by the same reference numerals as in the first embodiment and their description is omitted. In this embodiment, the male tapered portion 44c will be explained. Figure 6 is an enlarged cross-sectional view showing the opening 11a of the expansion valve 1 of this embodiment and its surrounding area. Figure 6 shows a state in which the orifice 13 is cut through a cross section that passes through the center and is parallel to both the vertical and width directions.

[0062] As shown in Figure 6, the male tapered portion 44c has a first conical surface 44c1 and a second conical surface 44c2. The first conical surface 44c1 is the portion of the male tapered portion 44c in the vertical direction, for example, from the middle to the upper end, and is a conical surface with axis X as its axis and a taper angle β with respect to axis X. The second conical surface 44c2 is the portion of the male tapered portion 44c in the vertical direction, for example, from the middle to the lower end, and is a conical surface with axis X as its axis, a taper angle Δ with respect to axis X, and β > Δ. Even in this embodiment, the same operation and effects as in the first embodiment can be obtained.

[0063] In other examples of this embodiment, the male tapered portion 44c may have three or more conical surfaces. Even in this case, the taper angle of each conical surface with respect to the axis X is smaller than the taper angle of the conical portion of the opening 11a with respect to the axis X.

[0064] In the second embodiment, an example was described in which the female tapered portion 11c has a plurality of conical surfaces, and in the third embodiment, an example was described in which the male tapered portion 44c has a plurality of conical surfaces. In other examples, the female tapered portion 11c may have a plurality of conical surfaces as in the second embodiment, and the male tapered portion 44c may have a plurality of conical surfaces as in the third embodiment.

[0065] In the first, second, and third embodiments, a receiving portion 11e is formed that can accommodate the lower part of the seal member 50, which has been compressed and crushed between the female tapered portion 11c and the male tapered portion 44c, thereby accommodating the lower part of the seal member 50 that has been extended in the vertical direction. In other examples, the vertical lengths of the female tapered portion 11c and the male tapered portion 44c may be made longer than the vertical length of the seal member 50 before it is crushed, so that the space between the lower end of the female tapered portion 11c and the lower end of the male tapered portion 44c can be used as a receiving portion to accommodate the lower part of the deformed seal member 50.

[0066] While embodiments of this disclosure have been described above with reference to the attached drawings, it is clear that any person with ordinary skill in the art to which this disclosure belongs can conceive of various modifications or applications within the scope of the technical idea described in the claims, and these also naturally fall within the technical scope of this disclosure. [Explanation of symbols]

[0067] 1...Expansion valve, 10...Valve body, 10a...Opening, 10b...Female threaded section, 12...Valve chamber, 13...Orifice, 20...Valve element, 30...Valve element support member, 40...Biasing device, 41...Coil spring, 42...Adjustment screw, 43a...Male threaded section, 50...Sealing member, 60...Power element, 70...Accelerating rod.

Claims

1. A valve body having a hole with an opening on its outer surface that extends in the longitudinal direction, and an orifice formed on the side of the hole opposite to the opening in the longitudinal direction, A closed-bottom cylindrical adjustment screw disposed within the hole and having a bottom on the opening side, wherein its outer circumferential surface is screwed into the inner circumferential surface of the hole, thereby allowing adjustment of its relative position in the longitudinal direction with respect to the valve body, and forming a valve chamber between itself and the inner circumferential surface of the hole, A valve body arranged in the valve chamber, A coil spring is positioned between the valve body and the adjustment screw, with a portion of it positioned within the adjustment screw, and biases the valve body toward the orifice. An annular sealing member provided between the adjustment screw and the inner circumferential surface of the hole, Equipped with, The inner circumferential surface of the hole has a female threaded portion into which the adjustment screw is screwed, and a female tapered portion formed on the orifice side relative to the female threaded portion, having a conical surface that decreases in diameter towards the orifice side. The outer circumferential surface of the adjustment screw has a male threaded portion that screws into the female threaded portion, and a male tapered portion formed on the orifice side relative to the male threaded portion, having a conical surface that decreases in diameter towards the orifice side. It has, The taper angle of the male tapered portion is smaller than the taper angle of the female tapered portion. The sealing member is in a state of plastic deformation due to compression between the female tapered portion and the male tapered portion. The portion of the outer circumferential surface of the sealing member that faces the female tapered portion has a shape that conforms to the female tapered portion. The portion of the inner circumferential surface of the sealing member that faces the male tapered portion has a shape that conforms to the male tapered portion. Expansion valve.

2. Between the female thread portion and the female tapered portion, the portion continuous with the female tapered portion is designated as the first portion. The portion between the male threaded portion and the male tapered portion that is continuous with the male tapered portion is designated as the second portion. The expansion valve according to claim 1, wherein the second portion is spaced apart from the first portion, and a housing portion capable of housing a part of the sealing member is formed between the first portion and the second portion.

3. The expansion valve according to claim 1, wherein the female tapered portion has a plurality of conical surfaces with different taper angles.

4. The expansion valve according to claim 1 or claim 3, wherein the male tapered portion has a plurality of conical surfaces with different taper angles.

5. A method for manufacturing an expansion valve as described in claim 1, The installation process involves inserting the coil spring into the adjustment screw, which is separated from the valve body, attaching the valve body to the coil spring, and attaching the sealing member to the male tapered portion. Insertion step of inserting the adjustment screw, the coil spring, the valve body, and the sealing member into the hole through the opening, A screwing process in which the sealing member is compressed and plastically deformed between the female tapered portion and the male tapered portion by rotating the adjustment screw, A method for manufacturing an expansion valve equipped with the following features.

6. The aforementioned screwing process is, A sealing step in which the sealing member is compressed between the female tapered portion and the male tapered portion to crush it by a predetermined amount in order to achieve a seal, After the sealing process, an adjustment process is performed in which the adjustment screw is further rotated to adjust the biasing force of the coil spring. A method for manufacturing an expansion valve according to claim 5, having the following characteristics:

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