Switching valve and refrigerating system

Abstract

The utility model discloses a switching valve and a refrigerating system. The switching valve comprises a valve body, a piston assembly and a pair of first elastic pieces. The valve body comprises an inner cavity with a first valve port and a second valve port; the piston assembly is movably arranged in the inner cavity between a first position for blocking the first valve port and a second position for blocking the second valve port; the pair of first elastic pieces is used for enabling the piston assembly to be in a balanced state; in the balance state, the piston assembly keeps still relative to the valve body under the condition of no fluid impact, when the piston assembly blocks one of the first valve port and the second valve port, the lengths of the pair of first elastic pieces are L1 and L2 respectively, L1 is larger than L2, the free lengths of the first elastic pieces are L 'and L2lt, L' is smaller than or equal to (L1 + L2) / 2, or L 'is larger than or equal to L1.

Description

Technical Field

[0001] This application relates to the technical field of valves. Specifically, it relates to a switching valve and a refrigeration system including the switching valve. Background Art

[0002] The switching valve in the related art includes a piston assembly and a spring. The spring is used to keep the piston assembly in a balanced state. During the switching process, as the spring is gradually compressed, the flow resistance needs to overcome a large elastic resistance, resulting in low operating ability of the valve. Sometimes, the valve cannot be fully closed or fully opened, affecting the reliability of the valve. Summary of the Utility Model

[0003] The embodiments of this application provide a switching valve and a refrigeration system to improve the operating ability of the switching valve.

[0004] The switching valve of the embodiments of this application includes a valve body, a piston assembly, and a pair of first elastic members. The valve body includes an inner cavity having a first valve port and a second valve port; the piston assembly is movably disposed in the inner cavity between a first position blocking the first valve port and a second position blocking the second valve port; a pair of first elastic members are used to keep the piston assembly in a balanced state; the balanced state means that: under no fluid impact, the piston assembly remains stationary relative to the valve body; wherein, when the piston assembly blocks one of the first valve port and the second valve port, the lengths of the pair of first elastic members are L1 and L2 respectively, L1 is greater than L2, the free length of the first elastic member is L', L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1.

[0005] According to some embodiments of this application, it further includes a pair of second elastic members for keeping the piston assembly in the balanced state; wherein, when the piston assembly blocks one of the first valve port and the second valve port, the lengths of the pair of second elastic members are L3 and L4 respectively, L3 is greater than L4, the free length of the second elastic member is L", L4 < L" < (L3 + L4) / 2, and L' ≥ L1.

[0006] According to some embodiments of this application, when the piston assembly blocks one of the first valve port and the second valve port, the second elastic force provided by the second elastic member to the piston assembly is greater than the first elastic force provided by the first elastic member to the piston assembly.

[0007] According to some embodiments of this application, L" is less than L'.

[0008] According to some embodiments of the present application, a partition portion is provided in the inner cavity. The partition portion separates the first valve port and the second valve port and has a guiding hole. The piston assembly is movably disposed through the guiding hole; a pair of the first elastic members are respectively located on both sides of the partition portion along the moving direction of the piston assembly, and a pair of the second elastic members are respectively located on both sides of the partition portion along the moving direction of the piston assembly.

[0009] According to some embodiments of the present application, the partition portion includes a partition ring and a guiding sleeve. The partition ring is fixedly connected to the inner wall of the inner cavity and is circumferentially connected to the outer periphery of the guiding sleeve. The guiding sleeve has the guiding hole; the piston assembly includes a piston rod, a first piston, and a second piston. The piston rod is movably disposed through the guiding hole. The first piston is connected to one end of the piston rod, and the second piston is connected to the other end of the piston rod; one ends of a pair of the first elastic members respectively abut against the partition ring, and the other ends respectively abut against the first piston and the second piston; one ends of a pair of the second elastic members respectively abut against the guiding sleeve, and the other ends respectively abut against the first piston and the second piston.

[0010] According to some embodiments of the present application, the guiding sleeve has a first limiting surface and a second limiting surface, and the first limiting surface and the second limiting surface are arranged opposite to each other along the axial direction of the piston rod; one ends of a pair of the second elastic members respectively abut against the first limiting surface and the second limiting surface.

[0011] According to some embodiments of the present application, the second elastic member is sleeved on the outer periphery of the piston rod, and the first elastic member is sleeved on the outer periphery of the second elastic member and is also sleeved on the outer periphery of the guiding sleeve.

[0012] According to some embodiments of the present application, the maximum flow area of the first valve port is S11, and the maximum flow area of the second valve port is S12; a first throttle passage communicating with the first valve port and a second throttle passage communicating with the second valve port are formed between the piston assembly and the inner wall of the inner cavity. The maximum flow area of the first throttle passage is S21, and the maximum flow area of the second throttle passage is S22; when the piston assembly is in the equilibrium state, S21 / S11 ≤ 3 / 10, S22 / S12 ≤ 3 / 10.

[0013] According to some embodiments of the present application, the first throttle passage is located outside the first valve port, and fluid flows to the first valve port through the first throttle passage; the second throttle passage is located outside the second valve port, and fluid flows to the second valve port through the second throttle passage.

[0014] According to some embodiments of the present application, when the piston assembly is in the balanced state, part of the piston assembly extends into the first valve port, and a third throttling channel is formed between the piston assembly and the pore wall of the first valve port. Part of the piston assembly extends into the second valve port, and a fourth throttling channel is formed between the piston assembly and the pore wall of the second valve port. The maximum flow area of the third throttling channel is S31, the maximum flow area of the fourth throttling channel is S32, S31 / S11 ≤ 3 / 10, and S32 / S12 ≤ 3 / 10.

[0015] According to some embodiments of the present application, during the process of the piston assembly blocking the first valve port, the flow area of the first throttling channel gradually decreases; during the process of the piston assembly blocking the second valve port, the flow area of the second throttling channel gradually decreases.

[0016] According to some embodiments of the present application, the valve body includes two first valve sleeves and a second valve sleeve arranged coaxially. The second valve sleeve is connected between the two first valve sleeves. The second valve sleeve has the first valve port and the second valve port; the inner peripheral surface of the first valve sleeve has an inner conical surface; alternatively, the outer peripheral surface of the piston assembly has an outer conical surface.

[0017] The refrigeration system of the embodiment of the present application includes the switching valve described in any one of the above.

[0018] One embodiment of the above application has at least the following advantages or beneficial effects:

[0019] For the switching valve of the embodiment of the present application, since the free length L' of the first elastic member satisfies: L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1, the resistance to be overcome during valve switching becomes smaller, thereby effectively improving the operating ability of the valve. Description of the Drawings

[0020] Figure 1 Shows an exploded view of the switching valve according to the first embodiment of the present application.

[0021] Figure 2 Shows a top view of the switching valve according to the first embodiment of the present application.

[0022] Figure 3 Shows along Figure 2 The cross-sectional view taken along the cutting line A-A in

[0023] Figure 4 Shows the flow area curve diagram of the switching valve when the ratio of the maximum flow area of the throttling channel to the maximum flow area of the valve port > 3 / 10 when the piston assembly is in the balanced state.

[0024] Figure 5Shown is the flow area curve diagram of the switching valve when the ratio of the maximum flow area of the throttle passage to the maximum flow area of the valve port ≤ 3 / 10 when the piston assembly is in the equilibrium state.

[0025] Figure 6 Shown is the flow resistance curve diagram of the switching valve when the ratio of the maximum flow area of the throttle passage to the maximum flow area of the valve port > 3 / 10 when the piston assembly is in the equilibrium state.

[0026] Figure 7 Shown is the flow resistance curve diagram of the switching valve when the ratio of the maximum flow area of the throttle passage to the maximum flow area of the valve port ≤ 3 / 10 when the piston assembly is in the equilibrium state.

[0027] Figure 8 Shown is the cross-sectional view of the switching valve of the second embodiment of the present application.

[0028] Figure 9 Shown is the cross-sectional view of the switching valve of the third embodiment of the present application.

[0029] Figure 10 Shown is the cross-sectional view of the switching valve of the fourth embodiment of the present application.

[0030] Figure 11 Shown is the cross-sectional view of the switching valve of the fifth embodiment of the present application.

[0031] Figure 12 Shown is the three-dimensional schematic diagram of the piston assembly of the switching valve of the fifth embodiment of the present application.

[0032] Figure 13 Shown is the exploded schematic diagram of the switching valve of the sixth embodiment of the present application.

[0033] Figure 14 Shown is the cross-sectional view of the switching valve of the sixth embodiment of the present application.

[0034] Figure 15 Shown is the curve schematic diagram of the elastic resultant force exerted on the piston assembly by a pair of first elastic members when the free length of the first elastic member in the switching valve of the sixth embodiment of the present application is in three different intervals.

[0035] Figure 16 Shown is the curve schematic diagram of the elastic resultant force when a pair of first elastic members and a pair of second elastic members act on the piston assembly simultaneously.

[0036] Figure 17 Shown is the exploded schematic diagram of the switching valve of the seventh embodiment of the present application.

[0037] Figure 18 Shown is the cross-sectional view of the switching valve of the seventh embodiment of the present application. Detailed implementation manners

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted.

[0039] It can be understood that the terms "comprising" and "having" and any variations thereof in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or components inherent to these processes, methods, products, or devices.

[0040]

Embodiment 1

[0041] As Figures 1 to 3 shown, the switching valve of the embodiments of this application includes a valve body 100, a piston assembly 200, and an elastic member. The valve body 100 includes an inner cavity 101 having valve ports (102a, 102b); the piston assembly 200 is movably disposed within the inner cavity 101 for blocking or opening the valve ports; the elastic member is used to keep the piston assembly 200 in a balanced state; wherein, when the piston assembly 200 is in a balanced state, a throttling channel communicating with the valve ports is formed between the piston assembly 200 and the cavity wall of the inner cavity 101. The ratio of the maximum flow area of the throttling channel to the maximum flow area of the valve ports ≤ 3 / 10 can enable the fluid to always generate a relatively large driving force on the piston assembly within the range from the balanced state to the complete closing of the valve ports, which is beneficial to improving the operating ability of the switching valve.

[0042] Among them, the valve ports include a first valve port 102a and a second valve port 102b, and the first valve port 102a and the second valve port 102b are spaced apart along the movement direction of the piston assembly 200. The piston assembly 200 is used to block the first valve port 102a and the second valve port 102b respectively. The maximum flow area of the first valve port 102a is S11, and the maximum flow area of the second valve port 102b is S12.

[0043] The maximum flow area of the valve ports refers to the fluid flow cross-sectional area when the valve ports are fully opened, that is, the opening area of the valve ports. The flow area of the throttling channel refers to the opening area of the flow area.

[0044] The elastic member includes a pair of first elastic members 310, which are respectively defined as a first elastic portion and a second elastic portion. The first elastic portion and the second elastic portion are used to maintain the stability of the piston assembly in the balanced state. And the first elastic portion is used to provide a first elastic force for the piston assembly 200 to move towards the position of closing the second valve port 102b, and the second elastic portion is used to provide a second elastic force for the piston assembly 200 to move towards the position of closing the first valve port 102a.

[0045] In an embodiment, when the piston assembly 200 is in the balanced state, the resultant force of the elastic forces exerted by the first elastic portion and the second elastic portion on the piston assembly 200 and the gravity of the piston assembly 200 is zero.

[0046] As Figure 1 and Figure 3 shown, the valve body 100 may include a valve seat 120 and a valve cover 130. The valve seat 120 has an inner cavity 101, and the valve cover 130 is connected to the valve seat 120. Wherein, the present application does not limit the connection manner between the valve cover 130 and the valve seat 120, such as screw connection, welding, interference fit, etc. Or the valve cover 130 and the valve seat 120 are integrally provided.

[0047] The valve cover 130 has a first opening 131, and the first opening 131 communicates with the inner cavity 101. The valve seat 120 has a second opening 121, and the second opening 121 communicates with the inner cavity 101. Wherein, when the piston assembly 200 closes the first valve port 102a, the first opening 131 and the second opening 121 are not in communication; when the piston assembly 200 closes the second valve port 102b, the first opening 131 and the second opening 121 are in communication. The first opening 131 can be used as the fluid inlet of the switching valve and is communicated with the outlet of the compressor. The second opening 121 can be used as the fluid outlet of the switching valve and is communicated with the inlet of the compressor. The end of the valve seat 120 away from the valve cover 130 can be used as another fluid inlet of the switching valve and can be communicated with the outlet of the compressor. Therefore, the switching valve can be a three-way valve, including two fluid inlets and one fluid outlet.

[0048] As Figure 3 shown, the piston assembly 200 includes a plug rod 210, a first piston 220 and a second piston 230. The first piston 220 is connected to one end of the plug rod 210 and is used to close the first valve port 102a. The second piston 230 is connected to the other end of the plug rod 210 and is used to close the second valve port 102b.

[0049] In an embodiment, the first elastic portion and the second elastic portion are compression springs and are sleeved on the outer periphery of the plug rod 210.

[0050] As Figure 3As shown, the valve seat 120 includes two first valve sleeves 122 and a second valve sleeve 123 connected between the two first valve sleeves 122. The first valve sleeves 122 and the second valve sleeve 123 are coaxially arranged. Both ends of the second valve sleeve 123 respectively form a first valve port 102a and a second valve port 102b.

[0051] Wherein, when the piston assembly 200 seals the first valve port 102a, one of the first valve sleeves 122 is sleeved on the outer periphery of the first piston 220; when the piston assembly 200 seals the second valve port 102b, the other first valve sleeve 122 is sleeved on the outer periphery of the second piston 230.

[0052] Of course, in other embodiments, the valve seat 120 may not include the first valve sleeve 122 but only have the second valve sleeve 123.

[0053] As Figure 3 shown, a partition part 110 is arranged in the inner cavity 101. The partition part 110 separates the first valve port 102a and the second valve port 102b; the first elastic part is located between the first piston 220 and the partition part 110, and one end of the first elastic part abuts against the partition part 110, and the other end abuts against the first piston 220. The second elastic part is located between the second piston 230 and the partition part 110, and one end of the second elastic part abuts against the partition part 110, and the other end abuts against the second piston 230.

[0054] In an embodiment, the partition part 110 includes a partition ring 111 and a guide sleeve 112. The partition ring 111 is fixedly connected to the inner peripheral surface of the second valve sleeve 123 and is circumferentially connected to the outer periphery of the guide sleeve 112. The guide sleeve 112 has a guide hole 110a, and the plug rod 210 is movably inserted into the guide hole 110a of the guide sleeve 112.

[0055] In the embodiment of the present application, the plug rod 210 is in guiding cooperation with the guide sleeve 112, which improves the stability of the movement of the plug rod 210 and further improves the reliability of the valve action.

[0056] In other embodiments, the partition part 110 may also include a partition ring 111, and the partition ring 111 encloses the guide hole 110a.

[0057] As Figure 3 shown, the partition ring 111 has a first ring surface 1111 and a second ring surface 1112. The first ring surface 1111 and the second ring surface 1112 are arranged back to back along the movement direction of the piston assembly 200; the part of the guide sleeve 112 extending out of the first ring surface 1111 is defined as a first section 112a, and the first elastic part is sleeved on the outer periphery of the first section 112a; the part of the guide sleeve 112 extending out of the second ring surface 1112 is defined as a second section 112b, and the second elastic part is sleeved on the outer periphery of the second section 112b.

[0058] AsFigure 3 As shown in the figure, the throttling passage includes a first throttling passage 410 communicating with the first valve port 102a and a second throttling passage 420 communicating with the second valve port 102b. The maximum flow area of the first throttling passage 410 is S21, and the maximum flow area of the second throttling passage 420 is S22. When the piston assembly 200 is in a balanced state, S21 / S11 ≤ 3 / 10 and S22 / S12 ≤ 3 / 10.

[0059] In the embodiment of the present application, the first throttling passage 410 is formed between the outer peripheral surface of the first piston 220 and the inner peripheral surface of one of the first valve sleeves 122, and the second throttling passage 420 is formed between the outer peripheral surface of the second piston 230 and the inner peripheral surface of the other first valve sleeve 122.

[0060] When the piston assembly 200 moves from a state where the flow area of the valve port is zero to a state where the valve port has the maximum flow area, the stroke is S1. When the piston assembly 200 is located between a state where the flow area of the valve port is zero and a state where the valve port has the maximum flow area, the stroke is S2. The valve port can be the first valve port 102a or the second valve port 102b. Figure 4 and Figure 5 The abscissa in represents the value of S2 / S1 of the switching valve, that is, the opening degree. Figure 4 and Figure 5 The ordinate in represents the ratio of the flow area of the valve port corresponding to different opening degrees of the switching valve to the maximum flow area of the valve port. The fluid flows into the valve port through the opening between the piston assembly 200 and the inner wall of the valve seat 120. Before the opening area reaches the opening area of the valve port, the flow area of the valve port is equal to the opening area between the piston assembly 200 and the inner wall of the valve seat 120. As the piston assembly 200 moves, when the opening area between the piston assembly 200 and the inner wall of the valve seat 120 decreases to a certain extent, the opening area between the piston assembly 200 and the inner wall of the valve seat 120 is the throttling passage area of this embodiment.

[0061] The high-pressure fluid enters the valve port through the throttling passage. After being throttled by the throttling passage, the fluid becomes low-pressure fluid, and the low-pressure fluid flows out from the second opening 121. The piston assembly 200 is subjected to the fluid pressure difference force before and after the valve port. Or the high-pressure fluid directly enters the throttling passage in the valve port and then becomes low-pressure fluid, and the low-pressure fluid flows out from the second opening 121. The piston assembly 200 is subjected to the fluid pressure difference force before and after the valve port. When the piston assembly 200 is at a state where the flow area of the valve port is zero, the fluid pressure difference before and after the valve port is F1. When the piston assembly 200 is between a state where the flow area of the valve port is zero and a state where the valve port has the maximum flow area, the fluid pressure difference before and after the valve port is F2. Figure 6 and Figure 7 The abscissa in represents the opening degree of the switching valve. Figure 6 and Figure 7 The ordinate in represents the value of F2 / F1 corresponding to different opening degrees of the switching valve.

[0062] For convenience of description, in the following descriptions of Figures 4 to 7 , the first valve port 102a is taken as an example. For example Figures 4 to 7 , in the abscissa of , 0% indicates the position of the piston assembly 200 when the piston assembly 200 seals the first valve port 102a; 100% in the abscissa indicates the position of the piston assembly 200 when the first valve port 102a is fully opened.

[0063] Figure 4 , Figure 6 and , when the piston assembly 200 is in the balanced state, the ratio of the maximum flow area of the throttle passage to the maximum flow area of the valve port > 3 / 10. It can be seen from Figure 4 that when the first valve port 102a is switched from the closed state to the fully opened state, the flow area gradually and steadily increases with the increase of the opening degree. When the opening degree of the piston assembly 200 reaches 50%, the flow area of the throttle passage is smaller than the maximum flow area of the valve port. At this time, the valve port flow area is equal to the flow area of the throttle passage, and the ratio of the valve port flow area to the maximum flow area of the valve port is slightly higher than 60%, and the value of F2 / F1 at this time is about 25%.

[0064] Figure 5 , Figure 7 and , when the piston assembly 200 is in the balanced state, the ratio of the maximum flow area of the throttle passage to the maximum flow area of the valve port ≤ 3 / 10. It can be seen from Figure 5 that when the first valve port 102a is switched from the closed state to the fully opened state, within the range where the opening degree of the piston assembly 200 reaches 50%, the valve port flow area remains basically unchanged with the increase of the valve opening stroke. When the opening degree of the piston assembly 200 reaches 55%, the flow area of the throttle passage is smaller than the maximum flow area of the valve port. At this time, the valve port flow area is equal to the flow area of the throttle passage, and the ratio of the valve port flow area to the maximum flow area of the valve port is about 8%, and the value of F2 / F1 at this time is about 95%. Therefore, it can be clearly seen that within the range where the opening degree of the piston assembly 200 reaches 55%, the piston assembly 200 is subjected to an increased fluid pressure difference driving force before and after the valve port, which is beneficial to improving the action ability of the valve. The fluid pressure difference driving force can not only overcome the elastic force exerted by the elastic member on the piston assembly 200, but also enable the piston assembly 200 to quickly switch between different working conditions. When performing the closing operation of the first valve port 102a, when the piston assembly 200 runs to the balanced state, a relatively large fluid pressure difference driving force can be obtained, and the fluid pressure difference driving force ensures the smooth closing of the first valve port 102a.

[0065] Such as Figure 5As shown, since a first throttling channel 410 is formed between the outer peripheral surface of the first piston 220 and the inner peripheral surface of the first valve sleeve 122, and S21 / S11 ≤ 3 / 10, the flow area of the first valve port 102a of the switching valve is relatively small in the opening range of 0% to 55%. When the valve opening stroke is in the range of 55% to 100%, the flow area of the first valve port 102a of the switching valve gradually increases. A relatively large fluid pressure difference driving force is generated in the opening range of 0% to 55%.

[0066] As can be seen Figure 6 from the figure, during the process of the first valve port 102a switching from the closed state to the fully open state, F2 quickly and gradually decreases, which is not conducive to improving the operating ability of the valve.

[0067] As can be seen Figure 7 from the figure, since a first throttling channel 410 is formed between the outer peripheral surface of the first piston 220 and the inner peripheral surface of the first valve sleeve 122, and S21 / S11 ≤ 3 / 10, F2 remains at a relatively large value in the opening range of 0% to 55%. When the opening is in the range of 55% to 100%, F2 gradually decreases, which is beneficial to driving the piston assembly 200 from the balanced state to the fully closed state.

[0068] It can be seen from this that for the switching valve of the embodiment of the present application, a throttling channel communicating with the valve port is formed between the piston assembly 200 and the cavity wall of the inner cavity 101. When the piston assembly 200 is in the balanced state, the ratio of the maximum flow area of the throttling channel to the maximum flow area of the valve port ≤ 3 / 10. Therefore, when the switching valve performs the switching action, within a certain valve opening stroke, the flow resistance received by the switching valve can be maintained at a relatively large value, which is beneficial to improving the operating ability of the switching valve and reducing the operating pressure difference.

[0069]

Embodiment 2

[0070] As Figure 8 shown, the same parts of the second embodiment of the present application and the first embodiment will not be described in detail. The differences are as follows:

[0071] When the piston assembly 200 is in the balanced state, the throttling channel further includes a third throttling channel 430 communicating with the first valve port 102a and a fourth throttling channel 440 communicating with the second valve port 102b. The maximum flow area of the third throttling channel 430 is S31, and the maximum flow area of the fourth throttling channel 440 is S32. S31 / S11 ≤ 3 / 10, S32 / S12 ≤ 3 / 10.

[0072] The first piston 220 and the second piston 230 both have insertion portions 240. When the piston assembly 200 is in a balanced state, the insertion portion 240 of the first piston 220 extends into the first valve port 102a, and a third throttling channel 430 is formed between the outer peripheral surface of the insertion portion 240 of the first piston 220 and the pore wall of the first valve port 102a. The insertion portion 240 of the second piston 230 extends into the second valve port 102b, and a fourth throttling channel 440 is formed between the insertion portion 240 of the second piston 230 and the pore wall of the second valve port 102b.

[0073] In the embodiment of the present application, when the piston assembly 200 is in a balanced state, not only the first throttling channel 410 and the second throttling channel 420 are provided, but also the third throttling channel 430 and the fourth throttling channel 440 are provided, further improving the operation ability of the switching valve.

[0074] Of course, it can be understood that in other embodiments, the switching valve may only be provided with the third throttling channel 430 and the fourth throttling channel 440, without providing the first throttling channel 410 and the second throttling channel 420.

[0075]

Embodiment Three

[0076] As Figure 9 shown, the same parts of the third embodiment of the present application and the first embodiment will not be described in detail. The differences are as follows:

[0077] During the process of the piston assembly 200 blocking the valve port, the flow area of the throttling channel formed between the inner peripheral surface of the first valve sleeve 122 and the piston assembly 200 gradually becomes smaller.

[0078] In the embodiment of the present application, during the process of the piston assembly 200 blocking the first valve port 102a, the flow area of the first throttling channel 410 gradually becomes smaller. During the process of the piston assembly 200 blocking the second valve port 102b, the flow area of the second throttling channel 420 gradually becomes smaller. Thus, the flow force generated by throttling gradually increases as the piston assembly 200 gradually blocks the valve port, and the elastic force of the first elastic portion gradually increases as the piston assembly 200 gradually blocks the valve port, so as to overcome the gradually increasing elastic force as the valve port closes, further improving the valve operation ability.

[0079] As Figure 9 shown, the inner peripheral surface of the first valve sleeve 122 has an inner conical surface 1221. By providing the inner conical surface 1221, not only can the valve operation ability be further improved, but also the piston assembly 200 can be prevented from being stuck in the first valve sleeve 122 due to the too narrow throttling channel.

[0080]

Embodiment Four

[0081] As Figure 10As shown in the figure, the same parts of the fourth embodiment of the present application as those of the third embodiment will not be described in detail. The differences are as follows:

[0082] The outer peripheral surfaces of the first piston 220 and the second piston 230 of the piston assembly 200 both have a first outer conical surface 250.

[0083]

Embodiment Five

[0084] As Figure 11 shown in the figure, the same parts of the fifth embodiment of the present application as those of the above embodiments will not be described in detail. The differences are as follows:

[0085] The piston assembly 200 includes a piston rod 210, a first piston 220 and a second piston 230. The first piston 220 and the second piston 230 are connected to the piston rod 210 and are arranged at intervals along the axial direction of the piston rod 210. The valve body 100 has a guiding portion 132, and the piston rod 210 is in guiding cooperation with the guiding portion 132. In the embodiment of the present application, the guiding portion 132 can guide the movement of the piston rod 210, thereby preventing the piston rod 210 from being deflected during movement and affecting the sealing performance of the piston for sealing the valve port. The guiding cooperation means that there is a small gap between the piston rod 210 and the guiding portion 132.

[0086] In one embodiment, the valve body 100 includes a valve cover 130 and a valve seat 120. The valve seat 120 has an inner cavity 101, and the valve cover 130 is connected to the valve seat 120. The guiding portion 132 is integrally formed on the valve cover 130.

[0087] Further, the first piston 220 is arranged close to the valve cover 130. The piston rod 210 has a guiding section 211, and the guiding section 211 is located on the side of the first piston 220 facing away from the second piston 230. The guiding section 211 is in guiding cooperation with the guiding portion 132.

[0088] In one embodiment, the guiding portion 132 can be a hole, and the guiding section 211 is in guiding cooperation with the inner wall surface of the hole.

[0089] As Figure 12 shown in the figure, both the first piston 220 and the second piston 230 include a first piston piece 260, a second piston piece 270 and a third piston piece 280. Among them, the second piston piece 270 is clamped between the first piston piece 260 and the third piston piece 280. The second piston piece 270 can be made of a rubber material, and the first piston piece 260 and the third piston piece 280 can be made of a metal material.

[0090] When the piston seals the valve port, the first piston piece 260 extends into the valve port. In the embodiment of the present application, when the first piston 220 seals the first valve port 102a, the first piston piece 260 of the first piston 220 extends into the first valve port 102a, and the second piston 230 is located outside the second valve port 102b; when the second piston 230 seals the second valve port 102b, the first piston piece 260 of the second piston 230 extends into the second valve port 102b, and the first piston 220 is located outside the first valve port 102a.

[0091] In an embodiment, the second piston piece 270 has a second outer conical surface 271 that is sealingly fitted with the valve port. By sealingly fitting the second outer conical surface 271 with the valve port, the sealing performance of the piston sealing the valve port can be improved.

[0092] As Figure 12 shown, the outer peripheral surface of the first piston piece 260 has an outer cylindrical surface 261 and two third outer conical surfaces 262. The two third outer conical surfaces 262 are symmetrically connected to both ends of the outer cylindrical surface 261 along the movement direction of the piston assembly 200. Among them, the diameter of the outer cylindrical surface 261 is slightly smaller than the diameter of the valve port.

[0093] In the embodiment of the present application, the outer peripheral surface of the first piston piece 260 has an outer cylindrical surface 261 and two third outer conical surfaces 262. On the one hand, it can prevent the first piston piece 260 from getting stuck at the edge of the valve port during the valve opening / closing process; on the other hand, since the two third outer conical surfaces 262 are symmetrically connected to both ends of the outer cylindrical surface 261 along the movement direction of the piston assembly 200, when assembling the first piston piece 260, there is no need to consider the front or back of the first piston piece 260, which improves the assembly efficiency.

[0094] It can be understood that the guiding portion 132, the second outer conical surface 271, the outer cylindrical surface 261, and the two third outer conical surfaces 262 in this embodiment are applicable to the switching valve of any of the above embodiments, and will not be listed one by one here.

[0095]

Embodiment Six

[0096] As Figure 13 and Figure 14 shown, the same parts of the sixth embodiment of the present application as those of the above embodiments will not be described in detail, and the differences are as follows:

[0097] The switching valve of the embodiment of the present application includes a valve body 100, a piston assembly 200, and an elastic member. The elastic member may include a pair of first elastic members 310. The pair of first elastic members 310 is used to keep the piston assembly 200 in a balanced state.

[0098] In an embodiment, the first elastic member 310 is a compression spring and is sleeved on the outer periphery of the plug rod 210.

[0099] As shown in Fig. 14, a partition portion 110 is provided in the inner cavity 101. The partition portion 110 separates the first valve port 102a and the second valve port 102b and has a guiding hole 110a. The plug rod 210 is movably inserted into the guiding hole 110a. One of the first elastic members 310 is located between the first piston 220 and the partition portion 110, and one end of this first elastic member 310 abuts against the partition portion 110, and the other end abuts against the first piston 220. The other first elastic member 310 is located between the second piston 230 and the partition portion 110, and one end of this other first elastic member 310 abuts against the partition portion 110, and the other end abuts against the second piston 230.

[0100] As Figure shown, the partition ring 111 has a first annular surface 1111 and a second annular surface 1112, and the first annular surface 1111 and the second annular surface 1112 are arranged opposite to each other along the movement direction of the piston assembly 200; the part of the guiding sleeve 112 extending out of the first annular surface 1111 is defined as the first section 112a, and one of the first elastic members 310 is sleeved on the outer periphery of the first section 112a; the part of the guiding sleeve 112 extending out of the second annular surface 1112 is defined as the second section 112b, and the other first elastic member 310 is sleeved on the outer periphery of the second section 112b.

[0101] Wherein, when the piston assembly 200 blocks one of the first valve port 102a and the second valve port 102b, the lengths of a pair of first elastic members 310 are L1 and L2 respectively, L1 is greater than L2, the free length of the first elastic member 310 is L', L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1. Herein, the "free length" refers to the length value when no external force is applied to both ends of the spring.

[0102] As ​ shown, it shows a schematic curve diagram of the elastic resultant force applied by a pair of first elastic members 310 on the piston assembly 200 when the free lengths of the first elastic members 310 are respectively in three different intervals. The three different intervals are: L' ≥ L1 (curve 1), (L1 + L2) / 2 < L' < L1 (curve 2), L2 < L' ≤ (L1 + L2) / 2 (curve 3).

[0103] Wherein, ​ the abscissa represents the opening degree of the switching valve, and the ordinate represents the ratio of the elastic resultant force corresponding to different opening degrees of the switching valve to the maximum elastic resultant force. The maximum elastic resultant force refers to the elastic resultant force applied by a pair of first elastic members 310 on the piston assembly 200 when the piston assembly 200 blocks one of the first valve port 102a and the second valve port 102b. The maximum elastic resultant forces applied by the three pairs of different first elastic members 310 corresponding to curve 1, curve 2, and curve 3 are all equal, that is, curve 1, curve 2, and curve 3 have the same starting point and the same ending point.

[0104] For the convenience of description, taking the first valve port 102a as an example, for instance ​ 0% in the abscissa represents the position of the piston assembly 200 when the piston assembly 200 blocks the first valve port 102a and the second valve port 102b is fully open; 100% in the abscissa represents the position of the piston assembly 200 when the first valve port 102a is fully open and the piston assembly 200 blocks the second valve port 102b. Among them, when the abscissa is 50%, it means that the piston assembly 200 is in a balanced state, that is, the resultant elastic force exerted on the piston assembly 200 by a pair of first elastic members 310 is zero.

[0105] It should be noted that 0% - 50% in the abscissa represents the movement of the piston assembly 200 from the first position (blocking the first valve port 102a) to the balanced state, and 50% - 100% represents the movement of the piston assembly 200 from the balanced state to the second position (blocking the second valve port 102b).

[0106] When the working condition is switched, at the position of 0% in the abscissa, the first valve port 102a is fully closed, the compressor is not shut down, and the high-pressure fluid starts to flow in from the bottom of the second piston 230. At this time, the pressure of the high-pressure fluid in the first valve port 102a has not started to decrease. At this time, the force pushing the piston assembly 200 to open the first valve port 102a is mainly the sum of the elastic forces of a pair of first elastic members 3,10. The sum of the elastic forces of a pair of first elastic members 310 opens the first valve port 102a. The greater the sum of the elastic forces of the first elastic members 310, the more capable it is to instantly open the first valve port 102a. That is, the magnitude of the elastic force of the first elastic members 310 is the key factor determining whether the first valve port 102a can be smoothly opened; within the range of 0% - 50% in the abscissa, the first valve port 102a opens first, and the second valve port 102b is also in an open state at the same time. The first valve port 102a, the second valve port 102b, and the inner cavity 101 of the valve body 100 are communicated. The pressure of the old high-pressure fluid in the first valve port 102a gradually decreases, and the new high-pressure fluid flows in from the bottom of the second piston 230. The high-pressure fluid and the fluid in the inner cavity 101 form a pressure difference. The fluid pressure formed by the pressure difference acts on the piston assembly 200. The fluid pressure and the sum of the elastic forces of a pair of first elastic members 310 push the piston assembly 200 to move to the position where it is in a balanced state. The direction of the fluid pressure is the same as the direction of the sum of the elastic forces of a pair of first elastic members 310.

[0107] After that, within the range of 50% to 100% on the abscissa, the direction of the fluid pressure is opposite to the direction of the sum of the elastic forces of a pair of first elastic members 310. The piston assembly 200 needs to overcome the sum of the elastic forces of the pair of first elastic members 310 and move until the second valve port 102b is in the closed state. Therefore, the sum of the elastic forces of the pair of first elastic members 310 serves as both the driving force for opening the first valve port 102a and the resistance for closing the second valve port 102b. Since the maximum sum of the elastic forces of the pair of first elastic members 310 corresponding to Curve 1, Curve 2, and Curve 3 are all equal, this application analyzes the elastic force that the switching valve needs to overcome during switching.

[0108] It can be seen from ​ that within the range of 50% to 100% on the abscissa, when the three curves have the same abscissa value, the resultant elastic force corresponding to Curve 1 and the resultant elastic force corresponding to Curve 2 are both smaller than the resultant elastic force corresponding to Curve 3. From this, it can be known that when the switching valve is switched, the resistance that the flow resistance in Curve 1 needs to overcome and the resistance that the flow resistance in Curve 2 needs to overcome are both smaller than the resistance that the flow resistance in Curve 3 needs to overcome.

[0109] Therefore, for the switching valve of the embodiment of this application, since the free length L' of the first elastic member 310 satisfies: L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1, the resistance that needs to be overcome during valve switching becomes smaller, thereby effectively improving the operating ability of the valve.

[0110] As ​ shown, the switching valve of the embodiment of this application further includes a pair of second elastic members 320 for keeping the piston assembly 200 in a balanced state.

[0111] In one embodiment, the second elastic member 320 is a compression spring and is sleeved on the outer periphery of the plug rod 210.

[0112] A pair of second elastic members 320 are respectively located on both sides of the partition portion 110 along the movement direction of the piston assembly 200; further, one end of a pair of second elastic members 320 respectively abuts against the guide sleeve 112, and the other end respectively abuts against the first piston 220 and the second piston 230; furthermore, the guide sleeve 112 has a first limiting surface 1121 and a second limiting surface 1122, and the first limiting surface 1121 and the second limiting surface 1122 are arranged opposite to each other along the axial direction of the plug rod 210; one end of a pair of the second elastic members 320 respectively abuts against the first limiting surface 1121 and the second limiting surface 1122. As an example, the first elastic member 310 is sleeved on the outer periphery of the second elastic member 320.

[0113] In one embodiment, the end of the first section 112a facing away from the second section 112b has a first limiting surface 1121, and the end of the second section 112b facing away from the first section 112a has a second limiting surface 1122.

[0114] When the piston assembly 200 blocks one of the first valve port 102 a and the second valve port 102 b , the second elastic force provided by the second elastic member 320 to the piston assembly 200 is greater than the first elastic force provided by the first elastic member 310 to the piston assembly 200 .

[0115] As an example, when the piston assembly 200 blocks one of the first valve port 102a and the second valve port 102b, the lengths of the pair of second elastic members 320 are L3 and L4 respectively, L3 is greater than L4, and the free length of the second elastic member 320 is L", L4 <L”<(L3+L4) / 2,且L’≥L1。其中,L”可以小于L’。

[0116] It should be noted that if ​ As shown, curve 2 (L2 <L’≤(L1+L2) / 2)中有弹性合力为零的行程(例如横坐标40%~60%),在这个区间下容易出现因弹性合力为零而导致活塞组件200不稳定而上下晃动,从而产生噪音振动的问题。L’≥L1时,活塞组件200始终与一对第二弹性件320接触,一对第二弹性件320对活塞组件200进行支撑,活塞组件200整个过程中稳定运行,不会出现晃动。

[0117] also, ​ Under the same horizontal coordinate, the elastic resultant force corresponding to curve 1 is greater than the elastic resultant force corresponding to curve 2. This will cause the piston assembly 200 to be subjected to a larger elastic force during the entire movement, which is not conducive to improving the movement capability.

[0118] Based on this, the switching valve of the embodiment of the present application is provided with a pair of first elastic members 310 and a pair of second elastic members 320. The free length of the first elastic member 310 is designed to be L'≥L1, and the free length of the second elastic member 320 is designed to be L4. <L”<(L3+L4) / 2,一对第一弹性件310和一对第二弹性件320的弹性合力在活塞组件200的整个运动行程中分别形成了两条曲线,两条曲线耦合后形成了如 ​ The curve shown. ​ The maximum elastic force exerted on the piston assembly 200 during the entire movement stroke is ​The maximum elastic force received by the piston assembly 200 shown during the entire movement stroke is equal. Moreover, when the piston assembly blocks one of the first valve port and the second valve port, the second elastic force provided by the second elastic member to the piston assembly is greater than the first elastic force provided by the first elastic member to the piston assembly, so that the piston assembly 200 moves towards the position where the equilibrium state is located under the action of the larger second elastic force. That is, the second elastic member with a larger elastic force effectively improves the action ability of the valve, and the elastic force of the larger second elastic member can smoothly open the first valve port 102a.

[0119] It can be seen from ​ that within the interval of the abscissa from 10% to 90%, only the resultant elastic force provided by a pair of first elastic members 310 acts on the piston assembly 200, and this resultant elastic force is relatively small. The resistance to be overcome during valve switching becomes smaller, thereby effectively improving the action ability of the valve; in addition, L'≥L1, and a pair of first elastic members can play a role in stabilizing the piston assembly to prevent the piston assembly 200 from generating noise and vibration.

[0120] Thus, it can be seen that the switching valve of the embodiment of the present application can take into account the problems of improving the action ability of the valve and preventing the piston assembly 200 from generating noise and vibration.

[0121] It can be understood that the design of this embodiment can be applied to the switching valves of any of the above embodiments, and will not be listed one by one here.

[0122]

Embodiment Seven

[0123] As ​ and ​ shown, the same parts of the seventh embodiment of the present application and the above embodiments will not be elaborated, and the differences are as follows:

[0124] The switching valve of the embodiment of the present application includes a valve body 100, a piston assembly 200, and an elastic member. The elastic member includes a pair of first elastic members 310. The valve body 100 has an inner cavity 101, and the inner cavity 101 has a first channel 102 and a second channel 103; the piston assembly 200 is movably arranged in the inner cavity 101 for blocking the first channel 102 and / or the second channel 103; wherein, the first channel 102 and the second channel 103 are arranged along the movement direction of the piston assembly 200. The elastic member is used to make the piston assembly 200 in an equilibrium state. When the piston assembly 200 is in an equilibrium state, the piston assembly 200 blocks both the first channel 102 and the second channel 103 at the same time.

[0125] In the switching valve according to the embodiment of the present application, when the piston assembly 200 is in a balanced state, both the first channel 102 and the second channel 103 are in a closed state. At this time, the fluid driving force applied to the piston assembly 200 due to throttling is the largest when the fluid passes through the switching valve. Therefore, the operating ability of the switching valve is maximally improved, and the reliability of the operation of the switching valve is enhanced. For example, the piston assembly can be switched from a state where the first channel 102 is blocked and the second channel 103 is open to a state where the second channel 103 is blocked and the first channel 102 is open. Among them, during the process of switching from the state where the first channel 102 is blocked and the second channel 103 is open to the state where the first channel 102 is blocked and the second channel 103 is blocked, the force driving the piston assembly 200 to move is the elastic member and the fluid force. When switching from the state where the first channel 102 is blocked and the second channel 103 is blocked to the state where the second channel 103 is blocked and the first channel 102 is open, it is necessary to overcome the elastic force of the elastic member. At this time, throttling occurs due to the blocking of the second channel 103, and the fluid driving force generated due to throttling can just overcome the elastic force of the elastic member. In one embodiment, the elastic member includes a pair of first elastic members 310. For the convenience of description, the pair of first elastic members 310 are respectively defined as a first elastic portion and a second elastic portion. The pair of first elastic members 310 can ensure the stability of the piston assembly 200 in a balanced state. In addition, the first elastic portion is used to provide a first elastic force for the piston assembly 200 to move towards the position blocking the second channel 103; the second elastic portion is used to provide a second elastic force for the piston assembly 200 to move towards the position blocking the first channel 102.

[0126] As ​ shown, a partition portion 110 is provided in the inner cavity 101, and the partition portion 110 divides the inner cavity 101 into a first channel 102 and a second channel 103; the first elastic portion is located in the first channel 102, and the second elastic portion is located in the second channel 103.

[0127] The piston assembly 200 includes a plug rod 210, a first piston 220, and a second piston 230. The first piston 220 is connected to an axial end of the plug rod 210 and is used to block the first channel 102. One end of the first elastic portion abuts against the partition portion 110, and the other end abuts against the first piston 220; the second piston 230 is connected to the other axial end of the plug rod 210 and is used to block the second channel 103. One end of the second elastic portion abuts against the partition portion 110, and the other end abuts against the second piston 230.

[0128] In the embodiment of the present application, one end of the first elastic portion abuts against the partition portion 110, and the other end abuts against the first piston 220. The first elastic force provided by the first elastic portion is used to make the first piston 220 have a tendency to open the first channel 102; one end of the second elastic portion abuts against the partition portion 110, and the other end abuts against the second piston 230. The second elastic force provided by the second elastic portion is used to make the second piston 230 have a tendency to open the second channel 103.

[0129] In one embodiment, the first elastic part and the second elastic part may be compression springs and are sleeved on the outer periphery of the plug rod 210.

[0130] The first piston 220 includes a first body 221 and a first sealing ring 222. The first body 221 is connected to one axial end of the plug rod 210. The first sealing ring 222 is sleeved on the outer periphery of the first body 221 and is used for sealing cooperation with the first channel 102. Among them, the first body 221 and the plug rod 210 may be connected by means of screwing, interference fit, welding, etc.

[0131] The second piston 230 includes a second body 231 and a second sealing ring 232. The second body 231 is connected to the other axial end of the plug rod 210. The second sealing ring 232 is sleeved on the outer periphery of the second body 231 and is used for sealing cooperation with the second channel 103. Among them, the second body 231 and the plug rod 210 may be connected by means of screwing, interference fit, welding, etc.

[0132] The partition part 110 includes a partition ring 111 and a guide sleeve 112. The partition ring 111 is fixedly connected to the wall of the inner cavity 101 and is circumferentially connected to the outer periphery of the guide sleeve 112. The plug rod 210 is movably inserted into the guide sleeve 112.

[0133] In the embodiment of the present application, the plug rod 210 is in guiding cooperation with the guide sleeve 112, which improves the stability of the movement of the plug rod 210 and further improves the reliability of the valve action.

[0134] As ​ shown, the two axial ends of the guide sleeve 112 have a first limiting surface 1121 and a second limiting surface 1122, and the first limiting surface 1121 and the second limiting surface 1122 are arranged opposite to each other along the movement direction of the piston assembly 200. The first limiting surface 1121 is configured to abut against the first piston 220 of the piston assembly 200 when the piston assembly 200 blocks the first channel 102 and moves to the first extreme position. The second limiting surface 1122 is configured to abut against the second piston 230 of the piston assembly 200 when the piston assembly 200 blocks the second channel 103 and moves to the second extreme position. In other words, when the piston assembly 200 is located at the first extreme position, the first limiting surface 1121 abuts against the first piston 220, and the second channel 103 is in the maximum open state; when the piston assembly 200 is located at the second extreme position, the second limiting surface 1122 abuts against the second piston 230, and the first channel 102 is in the maximum open state.

[0135] In the embodiment of the present application, by setting the first limiting surface 1121 and the second limiting surface 1122, the piston assembly 200 can be limited when it is located at the first extreme position and the second extreme position.

[0136] As​ As shown, the separating ring 111 has a first toroidal surface 1111 and a second toroidal surface 1112, and the first toroidal surface 1111 and the second toroidal surface 1112 are arranged away from each other along the movement direction of the piston assembly 200; the part of the guide sleeve 112 extending out of the first toroidal surface 1111 is defined as the first section 112a, and the first elastic part is sleeved on the outer periphery of the first section 112a; the part of the guide sleeve 112 extending out of the second toroidal surface 1112 is defined as the second section 112b, and the second elastic part is sleeved on the outer periphery of the second section 112b.

[0137] In another aspect of the present application, a refrigeration system is further provided, including the switching valve in any one of the above. Since the switching valve in any one of the above embodiments is included, the refrigeration system in the embodiments of the present application includes all the advantages and beneficial effects in any one of the above embodiments, which will not be elaborated here.

[0138] In summary, the switching valve and the refrigeration system in the embodiments of the present application at least have the following advantages and beneficial effects:

[0139] For the switching valve in the embodiments of the present application, since the free length L' of the first elastic member satisfies: L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1, the resistance to be overcome during valve switching becomes smaller, thereby effectively improving the operating ability of the valve.

[0140] It can be understood that the various embodiments / implementations provided in the present application can be combined with each other without contradiction, and no further examples will be given here.

[0141] In the embodiments of the application, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected to", and "fixed" should all be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the application can be understood according to specific circumstances.

[0142] In the description of the embodiments of the application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the application and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the application.

[0143] In the description of this specification, the descriptions of the terms "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0144] The above are only the preferred embodiments of the application embodiment and are not used to limit the application embodiment. For those skilled in the art, the application embodiment can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application embodiment shall be included within the protection scope of the application embodiment.

Claims

1. A switching valve, characterized in that, Comprising: A valve body including an inner cavity having a first valve port and a second valve port; A piston assembly movably disposed within the inner cavity between a first position closing the first valve port and a second position closing the second valve port; and A pair of first elastic members for keeping the piston assembly in a balanced state; the balanced state means that, without fluid impact, the piston assembly remains stationary relative to the valve body; Wherein, when the piston assembly closes one of the first valve port and the second valve port, the lengths of the pair of first elastic members are L1 and L2 respectively, L1 is greater than L2, the free length of the first elastic member is L', L2 < L' ≤ (L1 + L2) / 2, or L' ≥ L1.

2. The switching valve according to claim 1, wherein Further comprising: A pair of second elastic members for keeping the piston assembly in the balanced state; wherein, when the piston assembly closes one of the first valve port and the second valve port, the lengths of the pair of second elastic members are L3 and L4 respectively, L3 is greater than L4, the free length of the second elastic member is L", L4 < L" < (L3 + L4) / 2, and L' ≥ L1.

3. The switching valve according to claim 2, characterized in that, When the piston assembly closes one of the first valve port and the second valve port, the second elastic force provided by the second elastic member to the piston assembly is greater than the first elastic force provided by the first elastic member to the piston assembly.

4. The switching valve according to claim 2, wherein, L" is less than L'.

5. The switching valve according to claim 2, characterized in that A partition portion is provided within the inner cavity, the partition portion separates the first valve port and the second valve port and has a guiding hole, and the piston assembly is movably inserted through the guiding hole; The pair of first elastic members are respectively located on both sides of the partition portion along the movement direction of the piston assembly, and the pair of second elastic members are respectively located on both sides of the partition portion along the movement direction of the piston assembly.

6. The switching valve according to claim 5, characterized in that The partition portion includes a partition ring and a guiding sleeve, the partition ring is fixedly connected to the inner wall of the inner cavity and is circumferentially connected to the outer periphery of the guiding sleeve, and the guiding sleeve has the guiding hole; The piston assembly includes a piston rod, a first piston, and a second piston, the piston rod is movably inserted through the guiding hole, the first piston is connected to one end of the piston rod, and the second piston is connected to the other end of the piston rod; One ends of the pair of first elastic members respectively abut against the partition ring, and the other ends respectively abut against the first piston and the second piston; One ends of the pair of second elastic members respectively abut against the guiding sleeve, and the other ends respectively abut against the first piston and the second piston.

7. The switching valve according to claim 6, characterized in that, The guiding sleeve has a first limiting surface and a second limiting surface, and the first limiting surface and the second limiting surface are arranged opposite to each other along the axial direction of the piston rod; One ends of the pair of second elastic members respectively abut against the first limiting surface and the second limiting surface.

8. The switching valve according to claim 6, characterized in that, The second elastic member is sleeved on the outer periphery of the piston rod, the first elastic member is sleeved on the outer periphery of the second elastic member and is also sleeved on the outer periphery of the guiding sleeve.

9. The switching valve according to claim 1, wherein The maximum flow area of the first valve port is S11, and the maximum flow area of the second valve port is S12; A first throttling channel communicating with the first valve port and a second throttling channel communicating with the second valve port are formed between the piston assembly and the wall of the inner cavity. The maximum flow area of the first throttling channel is S21, and the maximum flow area of the second throttling channel is S22; When the piston assembly is in the equilibrium state, S21 / S11 ≤ 3 / 10 and S22 / S12 ≤ 3 / 10.

10. The switching valve according to claim 9, characterized in that, The first throttling channel is located outside the first valve port, and fluid flows to the first valve port through the first throttling channel; the second throttling channel is located outside the second valve port, and fluid flows to the second valve port through the second throttling channel.

11. The switching valve according to claim 9 or 10, characterized in that, When the piston assembly is in the equilibrium state, a part of the piston assembly extends into the first valve port, and a third throttling channel is formed between the piston assembly and the wall of the first valve port. A part of the piston assembly extends into the second valve port, and a fourth throttling channel is formed between the piston assembly and the wall of the second valve port. The maximum flow area of the third throttling channel is S31, and the maximum flow area of the fourth throttling channel is S32, and S31 / S11 ≤ 3 / 10 and S32 / S12 ≤ 3 / 10.

12. The switching valve according to claim 9, characterized in that, During the process of the piston assembly blocking the first valve port, the flow area of the first throttling channel gradually decreases; During the process of the piston assembly blocking the second valve port, the flow area of the second throttling channel gradually decreases.

13. The switching valve according to claim 12, characterized in that, The valve body includes two first valve sleeves and a second valve sleeve arranged coaxially. The second valve sleeve is connected between the two first valve sleeves, and the second valve sleeve has the first valve port and the second valve port; The inner peripheral surface of the first valve sleeve has an inner conical surface; alternatively, the outer peripheral surface of the piston assembly has an outer conical surface.

14. A refrigeration system, characterized in that, A switching valve according to any one of claims 1-13 is included.

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