Expansion valve and refrigeration device

Abstract

This indoor expansion valve (51) is an expansion valve for decompressing a refrigerant. The indoor expansion valve (51) comprises a valve main body (41), a first pipe (100), and a second pipe (200). The valve main body (41) has a valve chamber (43) in which a valve body (42) is accommodated. The first pipe (100) is connected to the valve chamber (43) along a first direction, which is an axial direction of the valve body (42). The second pipe (200) is connected to the valve chamber (43) along a second direction that intersects the first direction. In the second pipe (200), a wall thickness (T) at a reference position (L0), which is an end (200a) on the valve chamber (43) side, is smaller than a wall thickness (T) at a first position (L1) separated from the reference position (L0) by a first distance on the opposite side to the valve chamber (43) in the second direction.

Description

Expansion Valve and Refrigeration Device

[0008]

[0001] It relates to an expansion valve.

[0002] There has conventionally been an electric valve in which a rotor and a valve shaft rotate, and the valve body seats on a valve seat member to close the valve port (Patent Document 1 (Japanese Patent Application Laid-Open No. 2024-93962)).

[0003] In an expansion valve through which a two-phase refrigerant flows, if there is a groove in the valve chamber, liquid refrigerant is likely to enter, and the splashed liquid refrigerant may disrupt the flow of the high-velocity gas refrigerant, resulting in abnormal noise.

[0004] The expansion valve according to the first aspect is an expansion valve that reduces the pressure of the refrigerant, and includes a valve body, a first pipe, and a second pipe. The valve body has a valve chamber in which the valve body is accommodated. The first pipe is connected to the valve chamber along a first direction that is the axial direction of the valve body. The second pipe is connected to the valve chamber along a second direction that intersects the first direction. The wall thickness of the second pipe at a reference position that is the end on the valve chamber side is smaller than the wall thickness at a first position that is at a first distance from the reference position on the side opposite to the valve chamber in the second direction.

[0005] In this expansion valve, by reducing the wall thickness of the end of the second pipe on the valve chamber side, it is possible to suppress the refrigerant from colliding with the end of the second pipe and becoming droplets, thereby suppressing the generation of noise.

[0006] The expansion valve according to the second aspect is the expansion valve according to the first aspect, and the outer diameter of the second pipe at the reference position is the same as the outer diameter at the first position.

[0007] In this expansion valve, it is possible to suppress the generation of noise without changing the outer diameter at the reference position and the outer diameter at the first position.

[0008] The expansion valve according to the third aspect is the expansion valve according to the second aspect, and the wall thickness of the second pipe is the largest between a second position that is at a second distance greater than the first distance from the reference position on the side opposite to the valve chamber and a third position that is at a third distance greater than the second distance from the reference position on the side opposite to the valve chamber. The distance between the inner peripheral surface at the reference position and the inner peripheral surface at the second position is smaller than the distance between the reference position and the second position in the second direction.

[0009] In this expansion valve, noise generation can be suppressed by making the distance between the inner surface of the reference position and the inner surface of the second position smaller than the distance between the reference position and the second position in the second direction.

[0010] The expansion valve in the fourth view is the expansion valve in the third view, wherein the second pipe has a wall thickness at a fourth position, which is a fourth distance less than the second distance away from the reference position on the opposite side of the valve chamber, that is greater than the wall thickness at the reference position and smaller than the wall thickness at the second position.

[0011] In this expansion valve, the wall thickness at the fourth position, which is between the reference position and the second position, is greater than the wall thickness at the reference position and smaller than the wall thickness at the second position, thereby creating a slope on the inside of the second pipe.

[0012] The expansion valve in the fifth view is the expansion valve in the fourth view, and the second pipe has the same wall thickness at the fifth position, which is a fifth distance away from the reference position and is two distances smaller than the valve chamber, as it does at the reference position.

[0013] In this expansion valve, a horizontal section with a thin wall thickness and a slope can be formed inside the second pipe.

[0014] The expansion valve in the sixth viewpoint is the expansion valve in the first viewpoint, wherein the second pipe has an outer diameter at the reference position that is smaller than the outer diameter at the first position.

[0015] In this expansion valve, the outer diameter at the reference position is smaller than the outer diameter at the first position, which allows the refrigerant to flow more easily toward the inner wall of the second pipe.

[0016] The seventh aspect expansion valve is an expansion valve from either the first or sixth aspect, and its wall thickness at the reference position is 0.7 mm or more.

[0017] This expansion valve ensures strength at the end of the second pipe.

[0018] The expansion valve of the eighth perspective is an expansion valve of either the first or seventh perspective, and the valve body has a valve seat. The valve seat allows the flow area of ​​the refrigerant to be varied by the movement of the valve body. The valve body has an inclined portion. When the expansion valve is fully closed, the inclined portion is located on the first pipe side of the valve seat. When the expansion valve is in the first state, the inner wall of the second pipe is located on the extension of the inclined portion.

[0019] In this expansion valve, the inclined portion of the valve body guides the refrigerant toward the inner wall of the second pipe, thereby suppressing the refrigerant from colliding with the end of the second pipe and bouncing back.

[0020] The expansion valve in the ninth perspective is the expansion valve in the eighth perspective, and the first state is when the opening of the expansion valve is 5 to 40% of the opening when the fully open state is 100%.

[0021] In this expansion valve, when the valve opening is small, the refrigerant tends to become a two-phase gas-liquid system.

[0022] The expansion valve in the tenth viewpoint is the expansion valve in the eighth viewpoint, and the first state is a state in which there are no obstacles between the inclined portion and the inner wall of the second pipe on the extension of the inclined portion.

[0023] In this expansion valve, in the first state, the valve body moves away from the first pipe side, making it easier for the refrigerant to flow toward the inner wall of the second pipe.

[0024] The 11th aspect expansion valve is an expansion valve according to any of the 10th aspects from the 1st aspect, and the refrigerant is a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide.

[0025] This expansion valve can suppress noise even when high-pressure refrigerant is flowing through it.

[0026] The refrigeration apparatus according to the twelfth aspect comprises a utilization unit and a heat source unit. The utilization unit has an expansion valve as described in any of the first or eleventh aspects. The heat source unit is connected to the utilization unit.

[0027] In this refrigeration system, by reducing the wall thickness of the valve chamber end of the second pipe of the expansion valve, it is possible to suppress the refrigerant flowing from the first pipe of the expansion valve into the valve chamber from colliding with the end of the second pipe and becoming droplets, thereby suppressing noise generation.

[0028] This is a diagram showing the refrigeration cycle of an air conditioning system. This is a simplified diagram showing the pressure-enthalpy state of the CO2 refrigerant. This is a detailed diagram showing the pressure-enthalpy state of the CO2 refrigerant (a diagram using Fundamentals: 2005 Ashrae Handbook: Si Edition). This is a longitudinal cross-sectional view of the expansion valve according to this embodiment. This is a schematic cross-sectional view of the expansion valve according to this embodiment. This is a diagram showing an example of the cross-section of the second pipe. This is a diagram showing an example of the cross-section of the second pipe. This is a schematic cross-sectional view of the expansion valve according to Modification 1A. This is a diagram showing another example of the cross-section of the second pipe. This is a diagram showing another example of the cross-section of the second pipe. This is a schematic cross-sectional view of the expansion valve according to Modification 1B. This is a schematic cross-sectional view of the expansion valve according to Modification 1C. This is a schematic cross-sectional view of the expansion valve according to Modification 1D. This is a schematic cross-sectional view of the expansion valve according to Modification 1E. This is a schematic cross-sectional view of the expansion valve according to Modification 1F. This is a longitudinal cross-sectional view of the expansion valve according to Modification 1G. This is a diagram for explaining the state of the refrigerant.

[0029] (1) Overall configuration of the air conditioning system Figure 1 shows the refrigeration cycle of an air conditioning system 10 having a refrigeration system utilization unit employing the expansion valve of the present disclosure. The air conditioning system 10 comprises an indoor unit (refrigeration system utilization unit) 50 and an outdoor unit (refrigeration system heat source unit) 20. The indoor unit 50 has an indoor expansion valve (expansion valve) 51. The outdoor unit 20 is connected to the indoor unit 50. The air conditioning system 10 uses carbon dioxide (hereinafter referred to as CO2 refrigerant) as a refrigerant.

[0030] The air conditioning system 10 is a device installed in buildings such as office buildings to cool or heat multiple spaces, and is a multi-type air conditioning system in which multiple indoor units 50 are connected to one outdoor unit 20. This air conditioning system 10 consists of an outdoor unit 20, multiple indoor units 50, and refrigerant connecting pipes 6 and 7 that connect the two units 20 and 50.

[0031] The outdoor unit 20 includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an outdoor expansion valve 24, shut-off valves 25 and 26, and the like.

[0032] Each indoor unit 50 has an indoor expansion valve 51 and an indoor heat exchanger 52.

[0033] The indoor expansion valve 51 is an expansion valve that reduces the pressure of the refrigerant. The indoor expansion valve 51 is connected to the first connecting pipe 111, which is connected to the indoor heat exchanger 52. The indoor expansion valve 51 is also connected to the second connecting pipe 112, which is connected to the connection point with the refrigerant communication pipe 6.

[0034] The indoor units 50 are installed on the ceilings of each space (such as rooms) within the building and are connected to the outdoor units 20 by refrigerant connecting pipes 6 and 7.

[0035] As shown in Figure 1, the refrigeration cycle of this air conditioning system 10 is a closed circuit in which the compressor 21, four-way switching valve 22, outdoor heat exchanger 23, outdoor expansion valve 24, indoor expansion valve 51, and indoor heat exchanger 52 are connected by refrigerant piping including refrigerant connecting pipes 6 and 7.

[0036] (2) Basic operation of the air conditioning system The air conditioning system 10 can perform air conditioning operation to cool or heat the space inside the building by exchanging heat between the CO2 refrigerant flowing through the indoor heat exchanger 52 of the indoor unit 50 and the indoor air.

[0037] The air conditioning system 10 can switch between heating and cooling operation by switching the direction of refrigerant flow with the four-way switching valve 22.

[0038] During cooling operation, the outdoor heat exchanger 23 acts as a gas cooler, and the indoor heat exchanger 52 acts as an evaporator. On the other hand, during heating operation, the outdoor heat exchanger 23 acts as an evaporator, and the indoor heat exchanger 52 acts as a gas cooler.

[0039] In Figure 1, point A is the suction side of the compressor 21 during heating operation, and point B is the discharge side of the compressor 21 during heating operation. Point C is the refrigerant outlet side of the indoor heat exchanger 52 during heating operation, and point D is the refrigerant inlet side of the outdoor heat exchanger 23 during heating operation.

[0040] FIG. 2 is a diagram simply showing the pressure-enthalpy state of the CO2 refrigerant, with the vertical axis representing pressure and the horizontal axis representing enthalpy. FIG. 3 is a detailed diagram (drawing using Fundamentals: 2005 Ashrae Handbook: Si Edition) showing the pressure-enthalpy state of the CO2 refrigerant.

[0041] Tcp is an isotherm passing through the critical point CP. In the region on the right side of this isotherm Tcp and above the critical pressure which is the pressure at the critical point CP, the CO2 refrigerant becomes a supercritical state and turns into a fluid having both the diffusibility which is a property of a gas and the solubility which is a property of a liquid. As shown by the thick line in FIG. 2, the air conditioner 10 is operated in a refrigeration cycle including the supercritical state. In the refrigeration cycle of the heating operation, the CO2 refrigerant is compressed by the compressor 21 to a pressure exceeding the critical pressure, cooled by the indoor heat exchanger 52 to become a liquid, decompressed by the indoor expansion valve 51 and the outdoor expansion valve 24, evaporated by the outdoor heat exchanger 23, becomes a gas, and is inhaled into the compressor 21 again.

[0042] (3) Structure of the indoor expansion valve Next, the structure of the indoor expansion valve 51 will be described. FIG. 4 is a longitudinal sectional view of the indoor expansion valve 51. FIG. 5A is a schematic sectional view of the indoor expansion valve 51. FIGS. 5B and 5C are diagrams showing examples of the cross section of the second pipe 200. The arrow F in FIG. 5A indicates the flow direction of the refrigerant. In the present embodiment, the indoor expansion valve 51 is a motor-driven expansion valve. The indoor expansion valve 51 mainly includes a valve body 41, a first pipe 110, a second pipe 120, and a drive mechanism (not shown).

[0043] (3-1) Valve body The valve body 41 has a valve chamber 43 in which a valve element 42 is accommodated. Further, a guide member 46 is attached to the valve body 41 so as to be inserted into the valve chamber 43 from above.

[0044] The valve element 42 has a valve head portion 42a at one end and is advanced and retracted in the vertical direction (the first direction) by a drive mechanism (not shown). In the present embodiment, the valve element 42 has a needle shape and is arranged such that its axis is oriented in the vertical direction.

[0045] The valve body 41 includes a valve chamber 43 formed as a hollow space into which the valve element 42 is inserted, a first pipe 110 that opens to face the valve head 42a in order to connect the valve chamber 43 to the first pipe 111, a second pipe 120 that opens into the valve chamber 43 in a direction intersecting the valve element axis in order to connect the valve chamber 43 to the second pipe 112, and a valve seat 44 whose refrigerant flow passage area between the valve head 42a is variable by the forward and backward movement of the valve element 42. In the present embodiment, the valve body 41 is disposed below a drive mechanism (not shown).

[0046] Further, the valve body 41 has a valve seat 44. The valve seat 44 is a member having an orifice hole 45 against which the valve head 42a can abut. The valve seat 44 has its refrigerant flow passage area varied by the movement of the valve element 42.

[0047] The valve element 42 has an inclined portion 42b. The inclined portion 42b is located on the first pipe 100 side of the valve seat 44 when the opening degree of the indoor expansion valve 51 is in the fully closed state.

[0048] When the opening degree of the indoor expansion valve 51 is in the first state, the inner wall of the second pipe 200 is located on the extension line of the inclined portion 42b. In other words, when the opening degree of the indoor expansion valve 51 is in the first state, there is no obstacle between the inclined portion 42b and the inner wall of the second pipe 200 on the extension line of the inclined portion 42b. For example, as shown in FIG. 5A, when the opening degree of the indoor expansion valve 51 is in the first state, the guide lower surface 46a of the guide member 46 does not exist between the inclined portion 42b and the inner wall of the second pipe 200 on the extension line of the inclined portion 42b.

[0049] When the opening degree of the indoor expansion valve 51 is in the first state, the opening degree of the indoor expansion valve 51 is 5 to 40% of the fully open state when the fully open state is set to 10%. In the present embodiment, the opening degree of the indoor expansion valve 51 is 20% of the fully open state when the fully open state is set to 100% in the first state.

[0050] (3-2) First Pipe In the present embodiment, one end of the first pipe 100 is connected to the first pipe 111, and the other end is a pipe portion connected to the lower side of the valve chamber 43. The first pipe 110 is connected to the valve chamber 43a along the first direction (vertical direction) which is the axial direction of the valve element 42.

[0051] (3-3) Second pipe In this embodiment, the second pipe 200 is a pipe section in which one end is connected to the second pipe 112 and the other end is provided to open toward the valve body 42 from the side of the valve chamber 43. The second pipe 200 is connected to the valve chamber 43 along a second direction (left-right direction) that intersects the first direction.

[0052] In this embodiment, the second pipe 200 is fixed by a stopper 47.

[0053] As shown in Figures 5A to 5C, in this embodiment, the second pipe 200 has an inclined portion 200b in the radial direction, from a position between the outer and inner surfaces of the end 200a of the second pipe 200 toward the direction of refrigerant outflow, such that the inner diameter of the first position L1 becomes smaller than that of the reference position L0. In other words, the second pipe 200 has an inclined portion 200b starting from the middle of the pipe's wall thickness direction.

[0054] As shown in Figure 5B, the wall thickness T (wall thickness T0) of the second pipe 200 at reference position L0, which is the end 200a on the valve chamber 43 side, is smaller than the wall thickness T (wall thickness T1) at first position L1, which is a first distance away from the reference position L0 on the opposite side of the valve chamber 43 in the second direction. The wall thickness of the second pipe 200 at reference position L0 is 0.7 mm or more.

[0055] As shown in Figure 5C, the wall thickness T of the second pipe 200 is greatest between the second position L2, which is a second distance greater than the first distance from the reference position L0 on the opposite side of the valve chamber 43, and the third position L3, which is a third distance greater than the second distance from the reference position L0 on the valve chamber 43 side.

[0056] In this embodiment, the wall thickness T of the second pipe 200 between the second position L2 and the third position L3 is 1.2 mm. Furthermore, the wall thickness T (wall thickness T4) of the second pipe 200 at the fourth position L4, which is a fourth distance smaller than the second distance L2 on the opposite side of the valve chamber 43 from the reference position L0, is greater than the wall thickness T (wall thickness T0) at the reference position L0 and smaller than the wall thickness T (wall thickness T2) at the second position L2.

[0057] In this embodiment, the outer diameter of the second pipe 200 remains constant, and the inner circumference of the second pipe 200 has an inclined portion. Therefore, the outer diameter of the second pipe 200 at the reference position L0 is the same as the outer diameter at the first position L1.

[0058] The end portion 200a of the second pipe 200, which is the reference position L0, faces the valve chamber 43 and is the part of the second pipe 200 with the largest inner diameter.

[0059] The inner diameter of the second pipe 200 decreases in the direction of refrigerant outflow, starting from the end 200a, which is the reference position L0 of the second pipe 200.

[0060] The inner diameter of the second pipe 200 is smallest at the second position L2 and the third position.

[0061] (4) Operation of the Indoor Expansion Valve Next, the operation of the indoor expansion valve 51 will be explained.

[0062] When the compressor 21 and the like are started and the refrigerant begins to circulate within the refrigerant circuit 10 of the air conditioner 1, the liquid refrigerant from the indoor heat exchanger 52 flows through the first piping 111 and into the valve chamber 43 from the first pipe 100. The liquid refrigerant expands as it passes through the flow path formed by the valve head 42a and the orifice hole 45 of the valve seat 44, and is blown into the valve chamber 43, while also flowing in so as to collide with the inclined portion 200b on the inner circumference of the second pipe 200. The liquid refrigerant that has flowed into the valve chamber 43 then becomes a gas-liquid two-phase system, flows along the second direction, and flows out from the second pipe 200.

[0063] (5) Features (5-1) The indoor expansion valve 51 according to this embodiment is an expansion valve that reduces the pressure of the refrigerant. The indoor expansion valve 51 comprises a valve body 41, a first pipe 100, and a second pipe 200. The valve body 41 has a valve chamber 43 in which a valve element 42 is housed. The first pipe 100 is connected to the valve chamber 43 along a first direction which is the axial direction of the valve element 42. The second pipe 200 is connected to the valve chamber 43 along a second direction which intersects the first direction. The thickness T of the second pipe 200 at a reference position L0, which is the end 200a on the valve chamber 43 side, is smaller than the thickness T of the second pipe 200 at a first position L1 which is a first distance away from the reference position L0 on the opposite side of the valve chamber 43 in the second direction.

[0064] Figure 13 is a diagram illustrating the state of the refrigerant. When the opening of the indoor expansion valve 510 is, for example, 20% of the fully closed state (where the fully closed state is 100%), there is a gap between the valve seat 44 and the valve body 42. Because there is a gap around the valve body 42, there is naturally also a gap in the plane of the paper in Figure 13. In Figure 13, solid arrows indicate liquid refrigerant. Dashed arrows indicate gas-saturated refrigerant. In other words, the dashed arrows indicate gas-saturated refrigerant passing through the gap between the valve body 42 and the valve seat 44.

[0065] During heating operation, liquid CO2 refrigerant flows in through the first pipe 100 of the indoor expansion valve 510. As shown in Figure 13, if the wall thickness at the end 270a of the second pipe 270 of the indoor expansion valve 510 is not reduced and is at its maximum, a stepped groove 49 is created due to the remaining corner of the second pipe 270. Therefore, if the wall thickness at the end 270a of the second pipe 270 is large, the liquid refrigerant will become a ripple when passing through the indoor expansion valve 510 due to the step in the stepped groove 49. Then, the refrigerant passing through the second pipe 270 becomes a gas-liquid two-phase system due to pressure recovery.

[0066] In this embodiment, the indoor expansion valve 51 is connected such that, during heating operation of the air conditioning system 10, the liquid refrigerant flowing from the indoor heat exchanger 52 enters the lower side of the indoor expansion valve 51. In the indoor expansion valve 51, the liquid refrigerant flowing into the valve chamber 43 flows toward the inclined portion 200b on the inner circumference side of the second pipe 200. As a result, the noise generated when the refrigerant flowing from the first pipe 100 into the valve chamber 43 flows from the valve chamber 43 into the second pipe 200 is reduced.

[0067] In this embodiment, since the second pipe 200 has one inclined portion (inclined surface) 200b on its inner circumference, the cost of providing the inclined portion can be reduced.

[0068] In this indoor expansion valve 51, by reducing the wall thickness of the end 200a of the second pipe 200 on the valve chamber 43 side, it is possible to suppress the refrigerant from colliding with the end 200a of the second pipe 200 and becoming droplets, thereby suppressing the generation of noise.

[0069] (5-2) In the indoor expansion valve 51 according to this embodiment, the outer diameter of the second pipe 200 is the same at the reference position L0 and at the first position L1.

[0070] This indoor expansion valve 51 can suppress noise generation without changing the outer diameter of the reference position L0 and the outer diameter of the first position L1.

[0071] (5-3) In the indoor expansion valve 51 according to this embodiment, the wall thickness T of the second pipe 200 at the fourth position L4, which is a fourth distance smaller than the second distance from the reference position L0 on the opposite side from the valve chamber 43, is greater than the wall thickness T at the reference position L0 and smaller than the wall thickness T at the second position L2.

[0072] In this indoor expansion valve 51, the wall thickness T at the fourth position L4 between the reference position L0 and the second position L2 is greater than the wall thickness T at the reference position L0 and smaller than the wall thickness T at the second position L2, thereby creating a slope on the inside of the second pipe 200.

[0073] (5-4) In the indoor expansion valve 51 according to this embodiment, the wall thickness at the reference position L0 is 0.7 mm or more.

[0074] This indoor expansion valve 51 ensures the strength at the end 200a of the second pipe 200.

[0075] (5-5) In the indoor expansion valve 51 according to this embodiment, the valve body 41 has a valve seat 44. The flow area of ​​the refrigerant is varied by the movement of the valve element 42 of the valve seat 44. The valve element 42 has an inclined portion 42b. When the indoor expansion valve 51 is fully closed, the inclined portion 42b is located on the first pipe 100 side of the valve seat 44. When the indoor expansion valve 51 is in the first state, the inner wall of the second pipe 200 is located on the extension of the inclined portion 42b.

[0076] In this indoor expansion valve 51, the inclined portion 42b of the valve body 42 guides the refrigerant toward the inner wall of the second pipe 200, thereby suppressing the refrigerant from colliding with the end portion 200a of the second pipe 200 and bouncing back.

[0077] (5-6) In the indoor expansion valve 51 according to this embodiment, the first state is when the opening degree of the indoor expansion valve 51 is 20% of the opening degree, with the fully open state being 100%.

[0078] In this indoor expansion valve 51, when the opening degree of the indoor expansion valve 51 is small, the refrigerant tends to become a gas-liquid two-phase system.

[0079] (5-7) In the indoor expansion valve 51 according to this embodiment, the first state is a state in which there are no obstacles between the inclined portion 42b and the inner wall of the second pipe 200 on the extension of the inclined portion 42b.

[0080] In this indoor expansion valve 51, in the first state, the valve body 42 moves away from the first pipe 100 side, making it easier for the refrigerant to flow toward the inner wall of the second pipe 200.

[0081] (5-8) In the indoor expansion valve 51 according to this embodiment, the refrigerant is a single refrigerant consisting of carbon dioxide.

[0082] This indoor expansion valve 51 can suppress noise even when high-pressure refrigerant, such as CO2 refrigerant, is flowing through it.

[0083] (5-9) The air conditioning system 10 according to this embodiment comprises an indoor unit 50 and an outdoor unit 20. The indoor unit 50 has an indoor expansion valve 51. The outdoor unit 20 is connected to the indoor unit 50.

[0084] In this air conditioning system 10, by reducing the wall thickness of the end 200a of the second pipe 200 of the indoor expansion valve 51 on the valve chamber 43 side, it is possible to suppress the refrigerant flowing from the first pipe 100 of the indoor expansion valve 51 into the valve chamber 43 from colliding with the end 200a of the second pipe 200 and becoming droplets, thereby suppressing the generation of noise.

[0085] (6) Modifications (6-1) Modification 1A In this embodiment, the second pipe 200 has been described in which an inclined portion 200b is provided from the middle of the pipe's wall thickness direction, but it is not limited to this. The second pipe may also have an inclined portion provided from the middle of the pipe's axial direction. In Modification 1A, the second pipe 210 has a portion on its inner circumference that has a smaller wall thickness T along the second direction (left-right direction), and an inclined portion 210b.

[0086] Figure 6A is a schematic cross-sectional view of the indoor expansion valve 51a of Modification 1A. Figures 6B and 6C show examples of cross-sections of the second pipe 210 of the indoor expansion valve 51a of Modification 1A. The arrow F in Figure 6A indicates the direction of refrigerant flow.

[0087] As shown in Figure 6B, in the chamber expansion valve 51a of Modification 1A, the wall thickness T (wall thickness T2, T3) of the second pipe 210 is greatest between the second position L2, which is a second distance greater than the first distance from the reference position L0 on the opposite side of the valve chamber 43, and the third position L3, which is a third distance greater than the second distance from the reference position L0 on the opposite side of the valve chamber 43. Also, the distance A between the inner surface of the reference position L0 and the inner surface of the second position L2 is smaller than the distance B between the reference position L0 and the second position L2 in the second direction. Furthermore, for example, let's assume that the distance B between the reference position L0 and the second position L2 in the second direction is constant. Also, let's assume that the distance between the reference position L0 and the position with wall thickness T0 that is furthest from the valve chamber 43 in the second direction is constant. In this case, if the distance A between the inner surface of the reference position L0 and the inner surface of the second position L2 is further reduced, the inclination angle will decrease.

[0088] Furthermore, as shown in Figure 6C, in the chamber expansion valve 51a of modified example 1A, the wall thickness T (wall thickness T5) of the second pipe 210 at the fifth position L5, which is a fifth distance away from the reference position L0 and on the opposite side of the valve chamber 43 by a second distance, is the same as the wall thickness T (wall thickness T0) at the reference position L0.

[0089] The second pipe 210 has the same inner diameter at the reference position L0 and the fifth position. Also, the inner diameters at the second position L2 and the third position L3 are the same. Furthermore, it has an inclined section such that the inner diameters at the second position L2 and the third position L3 are smaller than the inner diameters at the reference position L0 and the fifth position L5.

[0090] In the indoor expansion valve 51a of Modified Example 1A, noise generation can be suppressed by making the distance A between the inner surface of the reference position L0 and the inner surface of the second position L2 smaller than the distance B between the reference position L0 and the second position L2 in the second direction. In addition, in Modified Example 1A, horizontal sections with a small wall thickness T and inclined sections can be formed on the inside of the second pipe 210.

[0091] (6-2) Modification 1B The second pipe of the indoor expansion valve may have an orthogonal plane intersecting it in the direction of the pipe axis at a position on the inner circumference side, away from the valve chamber side end of the second pipe and on the opposite side from the valve chamber.

[0092] Figure 7 is a schematic cross-sectional view of the indoor expansion valve 51b of Modification 1B. The arrow F in Figure 7 indicates the direction of refrigerant flow. As shown in Figure 7, in Modification 1B, the second pipe 220 has a horizontal portion with a small wall thickness along the second direction (left-right direction) and a vertical portion along the first direction (up-down direction) on the inner circumference side of the second pipe 220.

[0093] (6-3) Modification 1C The second pipe of the indoor expansion valve may have two or more inclined portions on its inner circumference and a horizontal portion located between the inclined portions.

[0094] Figure 8 is a schematic cross-sectional view of the indoor expansion valve 51c of Modification 1C. The arrow F in Figure 8 indicates the direction of refrigerant flow. As shown in Figure 8, in Modification 1C, the second pipe 230 has two inclined sections 230b and 230c on the inner circumference side of the second pipe 230, and a horizontal section with a small wall thickness along the second direction (left-right direction) between the two inclined sections 230b and 230c. The inner diameter of the inclined section 230b on the end 230a side is larger than the inner diameter of the horizontal section with a small wall thickness T, and the inner diameter of the horizontal section with a small wall thickness T is larger than the inner diameter of the inclined section 230c located on the opposite side from the valve chamber 43.

[0095] (6-4) Modification 1D The second pipe of the indoor expansion valve may have an inclined portion only at the upper two-thirds of the upper half of the radial cross-section of the second pipe.

[0096] Figure 9 is a schematic cross-sectional view of the indoor expansion valve 51d of modified example 1D. The arrow F in Figure 9 indicates the direction of refrigerant flow. As shown in Figure 9, in modified example 1D, the second pipe 240 has an inclined portion 240b on the inner circumference side of the side (upper side) fixed by the stopper 47, such that the inner diameter decreases from the end 240a toward the direction of refrigerant outflow.

[0097] (6-5) Modification 1E If there is a step between the stopper 47 and the second pipe of the indoor expansion valve, the shape of the valve chamber side of the second pipe may be made L-shaped to fill the step.

[0098] Figure 10 is a schematic cross-sectional view of the indoor expansion valve 51e of Modification 1E. The arrow F in Figure 10 indicates the direction of refrigerant flow. As shown in Figure 10, in Modification 1E, the end 250a of the second pipe 250 is L-shaped on the outer circumference side (upper side) where it is fixed by the stopper 47. This prevents a step from occurring between the stopper 47 and the second pipe 250.

[0099] (6-6) Modification 1F If there is a step between the stopper 47 and the second pipe, the outer diameter side of the second pipe of the indoor expansion valve on the valve chamber side may be made inclined around its entire circumference to fill the step.

[0100] Figure 11 is a schematic cross-sectional view of the indoor expansion valve 51f of Modification 1F. The arrow F in Figure 11 indicates the direction of refrigerant flow. As shown in Figure 11, in Modification 1F, the second pipe 260 has an inclined portion 260b on its outer surface such that the outer diameter increases in the direction of refrigerant outflow from the end 260a. In Modification 1F, the outer diameter of the second pipe 260 at reference position L0 of the end 260a is smaller than the outer diameter at a first position L1 which is a first distance away from the reference position L0 on the opposite side of the valve chamber 43.

[0101] In the modified example 1F, the indoor expansion valve 51f has a smaller outer diameter at the reference position L0 than at the first position L1, which makes it easier for the refrigerant to flow toward the inner wall of the second pipe 200.

[0102] (6-7) Modification 1G In this embodiment, the indoor expansion valve 51 has a stopper 47, but the indoor expansion valve does not need to have a stopper.

[0103] Figure 12 is a longitudinal cross-sectional view of the chamber expansion valve 51g of modified example 1G. As shown in Figure 12, the chamber expansion valve 51g according to modified example 1G comprises a valve body 41, a first pipe 100, a second pipe 200, and a drive mechanism (not shown). The valve body 41 also has a valve element 42, a valve chamber 43, a valve seat 44, an orifice hole 45, and a guide member 46. The first pipe 100 is joined to the valve chamber 43 of the valve body 41 along a first direction (vertical direction). The second pipe 200 is joined to the right side of the valve chamber 43 of the valve body 41 in Figure 12 along a second direction (horizontal direction).

[0104] In the modified example 1G, the indoor expansion valve 51g can suppress noise generation even without a stopper.

[0105] (6-8) Modification 1H In this embodiment, the case in which the refrigerant is a single refrigerant consisting of carbon dioxide has been described, but a mixed refrigerant containing carbon dioxide may also be used. Furthermore, the refrigerant is not limited to a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide.

[0106] (6-9) Modification 1I The expansion valve of the present disclosure is applicable to an outdoor expansion valve of a heat source unit of a refrigeration system.

[0107] (6-10) Although embodiments of the present disclosure have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the present disclosure as described in the claims.

[0108] 6, 7 Refrigerant connecting piping 10 Air conditioning system (refrigeration system) 20 Outdoor unit (heat source unit) 41 Valve body 42 Valve element 42a Valve head 42b Inclined part 43 Valve chamber 44 Valve seat 45 Orifice hole 46 Guide member 46a Guide bottom surface 47 Stopper 49 Stepped groove 50 Indoor unit (utilization unit) 51, 51a, 51b, 51c, 51d, 51e, 51f, 510 Indoor expansion valve (expansion valve) 100 First pipe 111 First connecting piping 112 Second connecting piping 200, 210, 220, 230, 240, 250, 260, 270 Second pipe 200a, 210a, 220a, 230a, 240a, 250a, 260a, 270a End portion 200b, 210b, 230b, 230c, 240b, 260b Inclined portion A, B Distance L0 Reference position L1 1st position L2 2nd position L3 3rd position L4 4th position L5 5th position T wall thickness

[0109] Japanese Patent Publication No. 2024-93962

Claims

1. An expansion valve for reducing the pressure of a refrigerant, comprising: a valve body (41) having a valve chamber (43) housing a valve element (42); a first pipe (100) connected to the valve chamber along a first direction which is the axial direction of the valve element; and second pipes (200, 210, 220, 230, 240, 250, 260) connected to the valve chamber along a second direction which intersects the first direction, wherein the wall thickness (T) of the second pipe at a reference position (L0), which is the end (200a) on the valve chamber side, is smaller than the wall thickness at a first position (L1) located a first distance away from the reference position on the opposite side of the valve chamber in the second direction, wherein the expansion valve (51, 51a, 51b, 51c, 51d, 51e, 51f).

2. The expansion valve according to claim 1, wherein the outer diameter of the second pipe at the reference position is the same as the outer diameter of the first position.

3. The expansion valve according to claim 2, wherein the second pipe has the greatest wall thickness between a second position (L2) located at a second distance greater than the first distance from the reference position on the opposite side of the valve chamber, and a third position (L3) located at a third distance greater than the second distance from the reference position on the opposite side of the valve chamber, and the distance (A) between the inner surface of the reference position and the inner surface of the second position is smaller than the distance (B) between the reference position and the second position in the second direction.

4. The expansion valve according to claim 3, wherein the second pipe has a wall thickness at a fourth position (L4) located at a fourth distance less than the second distance from the reference position on the opposite side of the valve chamber, and the wall thickness at the fourth position is greater than the wall thickness at the reference position and less than the wall thickness at the second position.

5. The expansion valve according to claim 4, wherein the second pipe has the same wall thickness at a fifth position (L5) located at a fifth distance (L5) that is a second distance smaller than the reference position and on the opposite side from the valve chamber, as is the same wall thickness at the reference position.

6. The expansion valve according to claim 1, wherein the outer diameter of the second pipe at the reference position is smaller than the outer diameter at the first position.

7. The expansion valve according to any one of claims 1 to 6, wherein the wall thickness at the reference position is 0.7 mm or more.

8. The expansion valve according to any one of claims 1 to 7, wherein the valve body has a valve seat (44) on which the flow area of ​​the refrigerant is varied by the movement of the valve body, the valve body has an inclined portion (42b) located on the first pipe side of the valve seat when the expansion valve is fully closed, and the inner wall of the second pipe is located on the extension of the inclined portion when the expansion valve is in a first state.

9. The expansion valve according to claim 8, wherein the first state is an opening of the expansion valve of 5 to 40% of the fully open state, with the fully open state being 100%.

10. The expansion valve according to claim 8, wherein the first state is a state in which there is no obstruction between the inclined portion and the inner wall of the second pipe on the extension of the inclined portion.

11. The expansion valve according to any one of claims 1 to 10, wherein the refrigerant is a single refrigerant consisting of carbon dioxide or a mixed refrigerant containing carbon dioxide.

12. A refrigeration apparatus (10) comprising: a utilization unit (50) having an expansion valve (51, 51a, 51b, 51c, 51d, 51e, 51f) according to any one of claims 1 to 11; and a heat source unit (20) connected to the utilization unit.

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