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 an elastic piece. The valve body comprises an inner cavity with a valve port. The piston assembly is movably arranged in the inner cavity and used for blocking or opening the valve port. The elastic piece is used for making the piston assembly in a balanced state. The balance state means that the piston assembly keeps still relative to the valve body under the condition of no fluid impact. A throttling channel communicated with the valve port is formed between the piston assembly and the cavity wall of the inner cavity, and when the piston assembly is in a balanced state, the ratio of the maximum flow area of the throttling channel to the maximum flow area of the valve port is smaller than or equal to 3 / 10.

Description

Technical Field

[0001] The present application relates to the field of valve technology, and in particular to a switching valve and a refrigeration system including the switching valve. Background Art

[0002] The switching valve in the related art can move in the valve cavity of the valve body under the drive of fluid pressure. If the pressure of the fluid acting on the switching valve is small, the switching valve will have low operating capacity, and sometimes the valve may not be fully closed or fully opened, affecting the reliability of the valve. Utility Model Content

[0003] The embodiments of the present application provide a switching valve and a refrigeration system to improve the action capability of the switching valve.

[0004] The switching valve of the embodiment of the present application comprises a valve body, a piston assembly and an elastic member. The valve body comprises an inner cavity having a valve port; the piston assembly is movably arranged in the inner cavity for blocking or opening the valve port; the elastic member is used to put the piston assembly in a balanced state; the balanced state means that: in the absence of fluid impact, the piston assembly remains stationary relative to the valve body; a throttling channel connected to the valve port is formed between the piston assembly and the cavity wall of the inner cavity; wherein, when the piston assembly 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 is ≤3 / 10.

[0005] According to some embodiments of the present application, when the piston assembly is in the balanced state, the throttling channel is formed between the inner circumferential surface of the valve port and the piston assembly.

[0006] According to some embodiments of the present application, the piston assembly has a second outer conical surface for sealingly cooperating with the valve port.

[0007] According to some embodiments of the present application, the piston assembly includes a first piston plate for extending into the valve port; the piston assembly also includes a second piston plate and a third piston plate, the second piston plate is clamped between the first piston plate and the third piston plate, and the second piston plate has a second outer conical surface that seals with the valve port.

[0008] According to some embodiments of the present application, the valve body includes a first valve sleeve and a second valve sleeve arranged coaxially, and the second valve sleeve has the valve port;

[0009] The throttling channel is formed between the inner circumferential surface of the first valve sleeve and the piston assembly and / or between the inner circumferential surface of the second valve sleeve and the piston assembly.

[0010] According to some embodiments of the present application, when the piston assembly is blocking the valve port, the flow area of ​​the throttling channel formed between the inner circumferential surface of the first valve sleeve and the piston assembly gradually decreases.

[0011] According to some embodiments of the present application, the inner circumferential surface of the first valve sleeve has an inner conical surface or the outer circumferential surface of the piston assembly has a first outer conical surface.

[0012] According to some embodiments of the present application, the valve port includes a first valve port and a second valve port, one end of the piston assembly is sealed with the first valve port, and the other end is sealed with the second valve port; the maximum flow area of ​​the first valve port is S11, and the maximum flow area of ​​the second valve port is S12; when the piston assembly is in the balanced state, the throttling channel includes a first throttling channel connected to the first valve port and a second throttling channel connected to the second valve port, the maximum flow area of ​​the first throttling channel is S21, and the maximum flow area of ​​the second throttling channel is S22; S21 / S11≤3 / 10, S22 / S12≤3 / 10.

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

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

[0015] According to some embodiments of the present application, the elastic member includes a first elastic portion and a second elastic portion, and the valve port includes a first valve port and a second valve port; a partition portion is provided in the inner cavity, and the partition portion separates the first valve port from the second valve port; the first elastic portion and the second elastic portion are respectively located on both sides of the partition portion along the movement direction of the piston assembly, one end of the first elastic portion abuts against the partition portion, and the other end abuts against one end of the piston assembly; one end of the second elastic portion abuts against the partition portion, and the other end abuts against the other end of the piston assembly.

[0016] According to some embodiments of the present application, the partition portion includes a partition ring and a guide sleeve, the partition ring is fixedly connected to the cavity wall of the inner cavity and is circumferentially connected to the outer circumference of the guide sleeve, and the piston assembly is movably disposed in the guide sleeve.

[0017] According to some embodiments of the present application, the piston assembly includes a plug rod and a piston, and the piston is connected to the plug rod to block the valve port;

[0018] The valve body has a guide portion, and the plug rod is in guiding cooperation with the guide portion.

[0019] According to some embodiments of the present application, the piston includes a first piston and a second piston arranged at an axial interval along the plug rod, the valve port includes a first valve port and a second valve port, the first piston is used to block or open the first valve port, and the second piston is used to block or open the second valve port; the plug rod has a guide section, the guide section is located on the side of the first piston facing away from the second piston, and the guide section cooperates with the guide portion.

[0020] The refrigeration system of the embodiment of the present application includes the switching valve described in any one of the above items.

[0021] One embodiment of the above application has at least the following advantages or beneficial effects:

[0022] In the switching valve of the embodiment of the present application, a throttling channel connected to the valve port is formed between the piston assembly and the cavity wall of the inner cavity. From the time when the piston assembly is in a balanced state to the range in which the valve port is completely closed, the fluid flows into the valve port through the throttling channel, or directly flows into the throttling channel in the valve port. After the fluid passes through the throttling channel, the pressure decreases. Therefore, the pressure change before and after the throttling channel will generate a driving force on the piston assembly toward the valve port, and the magnitude of the driving force is related to the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port. When the piston assembly is in a balanced state, the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is set to ≤3 / 10, so that the fluid can always generate a large driving force on the piston assembly from the time when the piston assembly is in a balanced state to the range in which the valve port is completely closed, which is beneficial to improving the action ability of the switching valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic exploded view of a switching valve according to the first embodiment of the present application.

[0024] Figure 2 Shown is a schematic top view of a switching valve according to the first embodiment of the present application.

[0025] Figure 3 Shown is along Figure 2 Section view along the AA cutting line.

[0026] Figure 4 The graph shows the flow area curve of the switching valve when the piston assembly is in a balanced state and the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is greater than 3 / 10.

[0027] Figure 5 The graph shows the flow area curve of the switching valve when the piston assembly is in a balanced state and the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10.

[0028] Figure 6 The figure shows the flow resistance curve of the switching valve when the piston assembly is in a balanced state and the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is greater than 3 / 10.

[0029] Figure 7 The figure shows the flow resistance curve of the switching valve when the piston assembly is in a balanced state and the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10.

[0030] Figure 8 Shown is a cross-sectional view of a switching valve according to a second embodiment of the present application.

[0031] Fig. 9 Shown is a cross-sectional view of a switching valve according to a third embodiment of the present application.

[0032] Fig.10 Shown is a cross-sectional view of a switching valve according to a fourth embodiment of the present application.

[0033] Fig.11 Shown is a cross-sectional view of a switching valve according to a fifth embodiment of the present application.

[0034] Fig.12 Shown is a three-dimensional schematic diagram of a piston assembly of a switching valve according to a fifth embodiment of the present application.

[0035] Fig.13 Shown is a schematic diagram of an exploded view of a switching valve according to a sixth embodiment of the present application.

[0036] Fig.14 Shown is a cross-sectional view of a switching valve according to a sixth embodiment of the present application.

[0037] Fig.15 It shows a curve diagram of the elastic 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.

[0038] Fig.16 What is shown is a curve diagram of the elastic force when a pair of first elastic members and a pair of second elastic members act on the piston assembly simultaneously.

[0039] Fig.17 Shown is a schematic diagram of an exploded view of a switching valve according to the seventh embodiment of the present application.

[0040] Fig.18 Shown is a cross-sectional view of a switching valve according to a seventh embodiment of the present application. DETAILED DESCRIPTION

[0041] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of 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 comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0042] It is understood that the terms "including" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. 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 may optionally include steps or units that are not listed, or may optionally include other steps or components that are inherent to these processes, methods, products, or devices.

[0043] [Example 1]

[0044] like Figures 1 to 3 As shown, the switching valve of the embodiment of the present application includes a valve body 100, a piston assembly 200 and an elastic member. The valve body 100 includes an inner cavity 101 having a valve port (102a, 102b); the piston assembly 200 is movably disposed in the inner cavity 101 for blocking or opening the valve port; 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 connected to the valve port 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 port is ≤3 / 10, so that the fluid can always generate a large driving force on the piston assembly within the range from the piston assembly being in a balanced state to the valve port being completely closed, which is beneficial to improving the action ability of the switching valve.

[0045] The valve port includes a first valve port 102a and a second valve port 102b, and the first valve port 102a and the second valve port 102b are arranged at intervals 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.

[0046] The maximum flow area of ​​the valve port refers to the cross-sectional area of ​​the fluid flow when the valve port is fully opened, that is, the opening area of ​​the valve port. The flow area of ​​the throttling channel refers to the opening area of ​​the flow area.

[0047] The elastic member includes a pair of first elastic members 310, which are defined as a first elastic portion and a second elastic portion, respectively. The first elastic portion and the second elastic portion are used to maintain the stability of the piston assembly in a balanced state. The first elastic portion is used to provide the piston assembly 200 with a first elastic force to move toward a position to block the second valve port 102b, and the second elastic portion is used to provide the piston assembly 200 with a second elastic force to move toward a position to block the first valve port 102a.

[0048] In one embodiment, when the piston assembly 200 is in a balanced state, the resultant force of the elastic force of the first elastic portion and the second elastic portion acting on the piston assembly 200 and the gravity of the piston assembly 200 is zero.

[0049] like Figure 1 and Figure 3 As 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. The present application does not limit the connection method between the valve cover 130 and the valve seat 120, such as threaded connection, welding, interference fit, etc. Or the valve cover 130 and the valve seat 120 are integrally arranged.

[0050] The valve cover 130 has a first opening 131, and the first opening 131 is connected to the inner cavity 101. The valve seat 120 has a second opening 121, and the second opening 121 is connected to the inner cavity 101. When the piston assembly 200 blocks the first valve port 102a, the first opening 131 is not connected to the second opening 121; when the piston assembly 200 blocks the second valve port 102b, the first opening 131 is connected to the second opening 121. The first opening 131 can be used as a fluid inlet of the switching valve, which is connected to the outlet of the compressor. The second opening 121 can be used as a fluid outlet of the switching valve, which is connected to the inlet of the compressor. One end of the valve seat 120 away from the valve cover 130 can be used as another inlet of the switching valve fluid, which can be connected to the outlet of the compressor. Therefore, the switching valve can be a three-way valve, including two fluid inlets and one fluid outlet.

[0051] like Figure 3 As 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 for blocking the first valve port 102a. The second piston 230 is connected to the other end of the plug rod 210 for blocking the second valve port 102b.

[0052] In one embodiment, the first elastic portion and the second elastic portion are compression springs, and are sleeved on the outer circumference of the plug rod 210 .

[0053] like Figure 3 As 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 sleeve 122 and the second valve sleeve 123 are coaxially arranged. The two ends of the second valve sleeve 123 form a first valve port 102a and a second valve port 102b respectively.

[0054] When the piston assembly 200 blocks 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 blocks the second valve port 102b, the other first valve sleeve 122 is sleeved on the outer periphery of the second piston 230.

[0055] Of course, in other embodiments, the valve seat 120 may not include the first valve sleeve 122 but may include the second valve sleeve 123 .

[0056] like Figure 3 As shown, a partition 110 is provided in the inner cavity 101, and the partition 110 separates the first valve port 102a from the second valve port 102b; the first elastic portion is located between the first piston 220 and the partition 110, and one end of the first elastic portion abuts against the partition 110, and the other end abuts against the first piston 220. The second elastic portion is located between the second piston 230 and the partition 110, and one end of the second elastic portion abuts against the partition 110, and the other end abuts against the second piston 230.

[0057] In one embodiment, the partition portion 110 includes a partition ring 111 and a guide sleeve 112. The partition ring 111 is fixedly connected to the inner circumference of the second valve sleeve 123 and is circumferentially connected to the outer circumference 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.

[0058] In the embodiment of the present application, the plug rod 210 cooperates with the guide sleeve 112 to improve the stability of the movement of the plug rod 210 and thus improve the reliability of the valve action.

[0059] In other embodiments, the partition 110 may also include a partition ring 111 , and the partition ring 111 surrounds the guide hole 110 a .

[0060] like Figure 3 As shown, the separation ring 111 has a first ring surface 1111 and a second ring surface 1112, and the first ring surface 1111 and the second ring surface 1112 are arranged opposite to each other along the movement direction of the piston assembly 200; the portion of the guide sleeve 112 extending out of the first ring surface 1111 is defined as a first section 112a, and the first elastic portion is sleeved on the outer periphery of the first section 112a; the portion of the guide sleeve 112 extending out of the second ring surface 1112 is defined as a second section 112b, and the second elastic portion is sleeved on the outer periphery of the second section 112b.

[0061] like Figure 3 As shown, the throttling channel includes a first throttling channel 410 connected to the first valve port 102a and a second throttling channel 420 connected to the second valve port 102b. The maximum flow area of ​​the first throttling channel 410 is S21, and the maximum flow area of ​​the second throttling channel 420 is S22. When the piston assembly 200 is in a balanced state, S21 / S11≤3 / 10, S22 / S12≤3 / 10.

[0062] In the embodiment of the present application, the first throttling channel 410 is formed between the outer circumference of the first piston 220 and the inner circumference of one of the first valve sleeves 122 , and the second throttling channel 420 is formed between the outer circumference of the second piston 230 and the inner circumference of the other first valve sleeve 122 .

[0063] When the piston assembly 200 moves from a valve port flow area of ​​zero to a valve port flow area of ​​maximum, the stroke is S1; when the piston assembly 200 is located between a valve port flow area of ​​zero and a valve port flow area of ​​maximum, the stroke is S2, and the valve port can be the first valve port 102a or the second valve port 102b. Figure 4 and Figure 5 The horizontal axis 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 valve port flow area corresponding to different openings 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 valve port opening area, the valve port flow area 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 is reduced to a certain extent, the opening area between the piston assembly 200 and the inner wall of the valve seat 120 is the throttling channel area of ​​this embodiment.

[0064] The high-pressure fluid enters the valve port through the throttling channel, and the fluid becomes a low-pressure fluid after being throttled by the throttling channel. The low-pressure fluid flows out from the second opening 121, and the piston assembly 200 is subjected to the fluid pressure difference force before and after the valve port. Alternatively, the high-pressure fluid directly enters the throttling channel in the valve port and becomes a low-pressure fluid. The low-pressure fluid flows out from the second opening 121, and the piston assembly 200 is subjected to the fluid pressure difference force before and after the valve port. When the flow area of ​​the valve port is zero, the piston assembly 200 is subjected to a fluid pressure difference of F1 before and after the valve port. When the flow area of ​​the valve port is between zero and the maximum flow area of ​​the valve port, the piston assembly 200 is subjected to a fluid pressure difference of F2 before and after the valve port. Figure 6 and Figure 7 The horizontal axis in represents the opening degree of the switching valve. Figure 6 and Figure 7The vertical axis in represents the value of F2 / F1 corresponding to different openings of the switching valve.

[0065] For the sake of convenience, the following Figures 4 to 7 The first valve port 102a is taken as an example in the description. Figures 4 to 7 0% in the abscissa indicates the position of the piston assembly 200 when the piston assembly 200 blocks 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.

[0066] Figure 4 , Figure 6 When the piston assembly 200 is in the equilibrium state, the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is greater than 3 / 10. Figure 4 It can be seen that when the first valve port 102a switches from a closed state to a fully open state, the flow area gradually and steadily increases with the increase of the opening. When the opening of the piston assembly 200 reaches 50%, the flow area of ​​the throttling channel is smaller than the maximum flow area of ​​the valve port. At this time, the flow area of ​​the valve port is equal to the flow area of ​​the throttling channel. The ratio of the flow area of ​​the valve port to the maximum flow area of ​​the valve port is slightly higher than 60%, and the value of F2 / F1 is about 25% at this time.

[0067] Figure 5 , Figure 7 When the piston assembly 200 is in the equilibrium state, the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10. Figure 5 It can be seen that when the first valve port 102a switches from the closed state to the fully open state, within the range of 50% of the opening of the piston assembly 200, the flow area of ​​the valve port remains basically unchanged as the valve opening stroke increases. When the opening of the piston assembly 200 reaches 55%, the flow area of ​​the throttling channel is smaller than the maximum flow area of ​​the valve port. At this time, the flow area of ​​the valve port is equal to the flow area of ​​the throttling channel. The ratio of the flow area of ​​the valve port to the maximum flow area of ​​the valve port is about 8%, and the value of F2 / F1 is about 95%. Therefore, it can be clearly seen that within the range of 55% of the opening of the piston assembly 200, the piston assembly 200 is subjected to the increased fluid pressure difference driving force before and after the valve port, which is conducive to improving the valve's operating ability. The fluid pressure difference driving force can not only overcome the elastic force applied to the piston assembly 200 by the elastic member, but also enable the piston assembly 200 to quickly switch between different working conditions. When the first valve port 102a is closed, the piston assembly 200 may have a relatively large fluid pressure difference driving force when it reaches a balanced state, and the fluid pressure difference driving force ensures the smooth closing of the first valve port 102a.

[0068] like Figure 5As shown, since the first throttling channel 410 is formed between the outer circumference of the first piston 220 and the inner circumference 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 small in the range of 0% to 55% of the opening. When the valve opening stroke is between 55% and 100%, the flow area of ​​the first valve port 102a of the switching valve gradually increases. A large fluid pressure difference driving force is generated in the range of 0% to 55% of the opening.

[0069] Depend on Figure 6 It can be seen that when the first valve port 102a switches from a closed state to a fully open state, F2 quickly and gradually decreases, which is not conducive to improving the action capacity of the valve.

[0070] Depend on Figure 7 It can be seen that since the first throttling channel 410 is formed between the outer circumferential surface of the first piston 220 and the inner circumferential surface of the first valve sleeve 122, and S21 / S11≤3 / 10, F2 is maintained at a larger value in the opening range of 0% to 55%, and F2 gradually decreases when the opening is between 55% and 100%, which is beneficial to push the piston assembly 200 from a balanced state to a fully closed state.

[0071] It can be seen that in the switching valve of the embodiment of the present application, a throttling channel connected to 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 a balanced state, the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10. Therefore, when the switching valve performs a switching action, within a certain valve opening stroke, the flow resistance of the switching valve can be maintained at a relatively large value, which is conducive to improving the action ability of the switching valve and reducing the action pressure difference.

[0072] [Example 2]

[0073] like Figure 8 As shown, the similarities between the second embodiment of the present application and the first embodiment are not repeated here, and the differences are as follows:

[0074] When the piston assembly 200 is in a balanced state, the throttling passage further includes a third throttling passage 430 communicating with the first valve port 102a and a fourth throttling passage 440 communicating with the second valve port 102b, the maximum flow area of ​​the third throttling passage 430 is S31, and the maximum flow area of ​​the fourth throttling passage 440 is S32. S31 / S11≤3 / 10, S32 / S12≤3 / 10.

[0075] The first piston 220 and the second piston 230 both have an insertion portion 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 passage 430 is formed between the outer peripheral surface of the insertion portion 240 of the first piston 220 and the hole wall of the first valve port 102a, and the insertion portion 240 of the second piston 230 extends into the second valve port 102b, and a fourth throttling passage 440 is formed between the insertion portion 240 of the second piston 230 and the hole wall of the second valve port 102b.

[0076] 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, which further improves the action capacity of the switching valve.

[0077] Of course, it is understandable that, in other embodiments, the switching valve may also 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 .

[0078] [Example 3]

[0079] like Fig. 9 As shown, the similarities between the third embodiment of the present application and the first embodiment are not repeated here, and the differences are as follows:

[0080] When the piston assembly 200 is blocking the valve port, the flow area of ​​the throttling channel formed between the inner circumferential surface of the first valve sleeve 122 and the piston assembly 200 gradually decreases.

[0081] In the embodiment of the present application, when the piston assembly 200 blocks the first valve port 102a, the flow area of ​​the first throttling channel 410 gradually decreases, and when the piston assembly 200 blocks the second valve port 102b, the flow area of ​​the second throttling channel 420 gradually decreases. In this way, the fluid force generated by throttling gradually increases as the piston assembly 200 gradually blocks the valve port, and the elastic force of the first elastic part gradually increases as the piston assembly 200 gradually blocks the valve port, which can overcome the elastic force that gradually increases as the valve port is closed, so as to further improve the valve action ability.

[0082] like Fig. 9 As shown, the inner circumference of the first valve sleeve 122 has an inner conical surface 1221. By providing the inner conical surface 1221, not only can the valve action capability be further improved, but also the piston assembly 200 can be prevented from being stuck in the first valve sleeve 122 due to the throttling passage being too narrow.

[0083] [Example 4]

[0084] like Fig.10As shown, the similarities between the fourth embodiment of the present application and the third embodiment are not repeated here, and the difference lies in that:

[0085] The outer circumferential surfaces of the first piston 220 and the second piston 230 of the piston assembly 200 both have a first outer conical surface 250 .

[0086] [Example 5]

[0087] like Fig.11 As shown, the similarities between the fifth embodiment of the present application and the above embodiments are not repeated here, and the differences are as follows:

[0088] The piston assembly 200 includes a plug rod 210, a first piston 220 and a second piston 230, wherein the first piston 220 and the second piston 230 are connected to the plug rod 210 and are arranged at intervals along the axial direction of the plug rod 210. The valve body 100 has a guide portion 132, and the plug rod 210 is guided and matched with the guide portion 132. In the embodiment of the present application, the guide portion 132 can guide the movement of the plug rod 210, thereby preventing the plug rod 210 from deflecting during movement and affecting the sealing of the piston blocking the valve port. The guide match means that there is a small gap between the plug rod 210 and the guide portion 132.

[0089] 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. The valve cover 130 is connected to the valve seat 120. The guide portion 132 is integrally formed on the valve cover 130.

[0090] Furthermore, the first piston 220 is disposed close to the valve cover 130 , and the plug rod 210 has a guide section 211 , which is located on a side of the first piston 220 facing away from the second piston 230 . The guide section 211 is in guiding cooperation with the guide portion 132 .

[0091] In one embodiment, the guide portion 132 may be a hole, and the guide section 211 is in guiding cooperation with the inner wall surface of the hole.

[0092] like Fig.12 As shown, the first piston 220 and the second piston 230 each include a first piston plate 260, a second piston plate 270 and a third piston plate 280. The second piston plate 270 is sandwiched between the first piston plate 260 and the third piston plate 280. The second piston plate 270 can be made of a rubber material, and the first piston plate 260 and the third piston plate 280 can be made of a metal material.

[0093] When the piston blocks the valve port, the first piston sheet 260 extends into the valve port. In the embodiment of the present application, when the first piston 220 blocks the first valve port 102a, the first piston sheet 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 blocks the second valve port 102b, the first piston sheet 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.

[0094] In one embodiment, the second piston plate 270 has a second outer conical surface 271 that seals with the valve port. The second outer conical surface 271 seals with the valve port to improve the sealing performance of the piston blocking the valve port.

[0095] like Fig.12 As shown, the outer peripheral surface of the first piston plate 260 has an outer cylindrical surface 261 and two third outer conical surfaces 262, and the two third outer conical surfaces 262 are symmetrically connected to the two ends of the outer cylindrical surface 261 along the movement direction of the piston assembly 200. The diameter of the outer cylindrical surface 261 is slightly smaller than the diameter of the valve port.

[0096] In the embodiment of the present application, the outer peripheral surface of the first piston plate 260 has an outer cylindrical surface 261 and two third outer conical surfaces 262. On the one hand, it can prevent the first piston plate 260 from being stuck on 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 the two ends of the outer cylindrical surface 261 along the movement direction of the piston assembly 200, when assembling the first piston plate 260, there is no need to consider the front or back side of the first piston plate 260, thereby improving the assembly efficiency.

[0097] It can be understood that the guide 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 are not listed one by one here.

[0098] [Example 6]

[0099] like Fig.13 and Fig.14 As shown, the similarities between the sixth embodiment of the present application and the above embodiments are not repeated here, and the differences are as follows:

[0100] 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.

[0101] In one embodiment, the first elastic member 310 is a compression spring and is sleeved on the outer circumference of the plug rod 210 .

[0102] As shown in 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 guide hole 110a. The plug rod 210 is movably inserted into the guide 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 the 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 the other first elastic member 310 abuts against the partition portion 110 and the other end abuts against the second piston 230.

[0103] As Fig.14 shown, the partition ring 111 has a first ring surface 1111 and a second ring surface 1112, and the first ring surface 1111 and the second ring surface 1112 are arranged in opposite directions along the movement direction of the piston assembly 200. The portion of the guide sleeve 112 extending from the first ring 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 portion of the guide sleeve 112 extending from the second ring 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.

[0104] 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.

[0105] As Fig.15 shown, it shows a schematic curve diagram of the elastic resultant force exerted by a pair of first elastic members 310 on the piston assembly 200 when the free lengths of the first elastic members 310 are 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).

[0106] Wherein, Fig.15 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 exerted 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 exerted on the piston assembly 200 by 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.

[0107] For the convenience of explanation, the first valve port 102a is taken as an example. Fig.15 0% in the horizontal axis indicates 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 opened; 100% in the horizontal axis indicates the position of the piston assembly 200 when the first valve port 102a is fully opened and the piston assembly 200 blocks the second valve port 102b. When the horizontal axis is 50%, it indicates that the piston assembly 200 is in a balanced state, that is, the elastic force exerted on the piston assembly 200 by the pair of first elastic members 310 is zero.

[0108] It should be noted that 0% to 50% in the horizontal axis indicates that the piston assembly 200 moves from the first position (blocking the first valve port 102a) to the equilibrium state, and 50% to 100% indicates that the piston assembly 200 moves from the equilibrium state to the second position (blocking the second valve port 102b).

[0109] When switching the working state, at the position of 0% on the horizontal axis, the first valve port 102a is completely closed, the compressor is not stopped, and the high-pressure fluid begins 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 yet begun to decrease. At this time, the force that pushes 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 310. 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 the first valve port 102a can be opened instantly, that is, the elastic force of the first elastic member 310 determines whether the first valve port 102a can be opened smoothly. The key factor of the valve port 102a is that the first valve port 102a is opened first, and the second valve port 102b is in an open state at the same time within the range of 0% to 50% of the horizontal axis. The first valve port 102a, the second valve port 102b, and the inner cavity 101 of the valve body 100 are connected. 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 sum of the fluid pressure and the elastic force of the pair of first elastic members 310 pushes the piston assembly 200 to move to the position of the equilibrium state. The direction of the fluid pressure is the same as the direction of the sum of the elastic forces of the pair of first elastic members 310.

[0110] 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 a 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.

[0111] It can be seen from Fig.15 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.

[0112] 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.

[0113] As Fig.14 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.

[0114] In one embodiment, the second elastic member 320 is a compression spring and is sleeved on the outer periphery of the plug rod 210.

[0115] 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 in opposite directions along the axial direction of the plug rod 210; one end of the pair of 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.

[0116] In one embodiment, one end of the first section 112a facing away from the second section 112b has a first limiting surface 1121, and one end of the second section 112b facing away from the first section 112a has a second limiting surface 1122.

[0117] When the piston assembly 200 blocks one of the first valve port 102a and the second valve port 102b, 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.

[0118] 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 a pair of second elastic members 320 are L3 and L4 respectively, L3 is greater than L4, the free length of the second elastic member 320 is L”, L4 < L” < (L3 + L4) / 2, and L’ ≥ L1. Among them, L” can be less than L’.

[0119] It should be noted that, as Fig.15 shown, there is a stroke with zero elastic resultant force in the curve 2 (L2 < L’ ≤ (L1 + L2) / 2) (for example, the abscissa is 40% - 60%). In this interval, it is easy to have problems such as the piston assembly 200 being unstable and shaking up and down due to the zero elastic resultant force, resulting in noise and vibration. When L’ ≥ L1, the piston assembly 200 is always in contact with a pair of second elastic members 320, and a pair of second elastic members 320 support the piston assembly 200, and the piston assembly 200 operates stably throughout the process without shaking.

[0120] In addition, Fig.15 at the same abscissa in, the elastic resultant force corresponding to curve 1 is greater than the elastic resultant force corresponding to curve 2. In this way, the piston assembly 200 will be subjected to a relatively large elastic force throughout the movement formation, which is not conducive to improving the action ability.

[0121] 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, the free length of the second elastic member 320 is designed to be L4 < L” < (L3 + L4) / 2. The elastic resultant forces of a pair of first elastic members 310 and a pair of second elastic members 320 respectively form two curves during the entire movement stroke of the piston assembly 200, and the two curves are coupled to form a curve as Fig.16 shown. Fig.16 in which the maximum elastic resultant force received by the piston assembly 200 during the entire movement stroke and Figure 4The maximum elastic force on the piston assembly 200 shown in the figure is equal in the whole movement stroke, and 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 to the position of the equilibrium state 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.

[0122] Depend on Fig.16 It can be seen that in the range of 10% to 90% of the horizontal axis, only the elastic force provided by a pair of first elastic members 310 acts on the piston assembly 200, and the elastic force is relatively small, so the resistance to be overcome when the valve is switched becomes smaller, thereby effectively improving the valve's operating ability; in addition, L'≥L1, the pair of first elastic members can stabilize the piston assembly and prevent the piston assembly 200 from generating noise and vibration.

[0123] It can be seen that the switching valve in the embodiment of the present application can take into account the action ability of the lifting valve and prevent the piston assembly 200 from generating noise and vibration.

[0124] It can be understood that the design of this embodiment can be applied to the switching valve of any of the above embodiments, and they are not listed one by one here.

[0125] [Example 7]

[0126] like Fig.17 and Fig.18 As shown, the same points as the above-mentioned embodiments in the seventh embodiment of the present application will not be repeated, and the difference lies in that:

[0127] The switching valve of the embodiment of the present application includes a valve body 100, a piston assembly 200 and an elastic member, wherein 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, and is used to block 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 a balanced state. When the piston assembly 200 is in a balanced state, the piston assembly 200 blocks the first channel 102 and the second channel 103 at the same time.

[0128] In the switching valve of the embodiment of the present application, when the piston assembly 200 is in a balanced state, the first channel 102 and the second channel 103 are both in a closed state. At this time, the fluid driving force applied to the piston assembly 200 by throttling when the fluid passes through the switching valve is the largest, thereby maximizing the action ability of the switching valve and improving the reliability of the switching valve action. For example, the piston assembly can be switched from the state where the first channel 102 is blocked and the second channel 103 is open to the state where the second channel 103 is blocked and the first channel 102 is open. Among them, in 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 the state where the first channel 102 is blocked and the second channel 103 is blocked is switched to the state where the second channel 103 is blocked and the first channel 102 is open, the elastic force of the elastic member needs to be overcome, and at this time, throttling is caused by the blocking of the second channel 103, and the fluid driving force generated by 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 ease of description, the pair of first elastic members 310 are defined as a first elastic portion and a second elastic portion, respectively. 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 the piston assembly 200 with a first elastic force to move toward a position to block the second channel 103; the second elastic portion is used to provide the piston assembly 200 with a second elastic force to move toward a position to block the first channel 102.

[0129] like Fig.18 As shown, a partition 110 is provided in the inner cavity 101 , and the partition 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 .

[0130] 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 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 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, and one end of the second elastic portion abuts against the partition 110, and the other end abuts against the second piston 230.

[0131] 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.

[0132] In one embodiment, the first elastic portion and the second elastic portion may be compression springs, and are sleeved on the outer circumference of the plug rod 210 .

[0133] 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 circumference of the first body 221 and is used to seal with the first channel 102. The first body 221 and the plug rod 210 can be connected by screw connection, interference fit, welding, etc.

[0134] 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 circumference of the second body 231 and is used to seal with the second channel 103. The second body 231 and the plug rod 210 can be connected by screw connection, interference fit, welding, etc.

[0135] The partition part 110 includes a partition ring 111 and a guide sleeve 112 . The partition ring 111 is fixedly connected to the cavity wall of the inner cavity 101 and is connected to the outer circumference of the guide sleeve 112 . The plug rod 210 is movably inserted into the guide sleeve 112 .

[0136] In the embodiment of the present application, the plug rod 210 cooperates with the guide sleeve 112 to improve the stability of the movement of the plug rod 210 and thus improve the reliability of the valve action.

[0137] like Fig.18 As shown, the guide sleeve 112 has a first limiting surface 1121 and a second limiting surface 1122 at both axial ends, and the first limiting surface 1121 and the second limiting surface 1122 are arranged opposite to each other along the moving 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 limit position, and 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 limit position. In other words, when the piston assembly 200 is located at the first limit 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 limit position, the second limiting surface 1122 abuts against the second piston 230, and the first channel 102 is in the maximum open state.

[0138] In the embodiment of the present application, by providing 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 limit position and the second limit position.

[0139] like Fig.18 As shown, the separation ring 111 has a first ring surface 1111 and a second ring surface 1112, and the first ring surface 1111 and the second ring surface 1112 are arranged opposite to each other along the movement direction of the piston assembly 200; the portion of the guide sleeve 112 extending out of the first ring surface 1111 is defined as a first section 112a, and the first elastic portion is sleeved on the outer periphery of the first section 112a; the portion of the guide sleeve 112 extending out of the second ring surface 1112 is defined as a second section 112b, and the second elastic portion is sleeved on the outer periphery of the second section 112b.

[0140] In another aspect of the present application, a refrigeration system is provided, comprising any of the switching valves described above. Since the switching valves described above are included, the refrigeration system of the present application embodiment includes all the advantages and beneficial effects of any of the above embodiments, which will not be described in detail here.

[0141] In summary, the switching valve and refrigeration system of the embodiment of the present application have at least the following advantages and beneficial effects:

[0142] In the switching valve of the embodiment of the present application, when the piston assembly 200 is in a balanced state, a throttling channel connected to the valve port is formed between the piston assembly 200 and the cavity wall of the inner cavity 101, and the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10. Therefore, when the switching valve performs a switching action, within a certain valve opening stroke, the flow resistance of the switching valve can be maintained at a relatively large value, which is conducive to improving the action ability of the switching valve and reducing the action pressure difference.

[0143] It is understandable that the various embodiments / implementations provided in the present application can be combined with each other without causing any contradiction, and will not be illustrated one by one here.

[0144] In the application embodiments, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. The terms "installed", "connected", "connected", "fixed", etc. should 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 application embodiments can be understood according to the specific circumstances.

[0145] In the description of the application embodiments, it should be understood that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the application embodiments 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, should not be understood as a limitation on the application embodiments.

[0146] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the application embodiment. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0147] The above are only preferred embodiments of the application embodiments and are not intended to limit the application embodiments. For those skilled in the art, the application embodiments may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application embodiments shall be included in the protection scope of the application embodiments.

Claims

1. A switching valve, characterized in that: include: A valve body including an inner cavity having a valve port; A piston assembly, movably disposed in the inner cavity, for blocking or opening the valve port; An elastic member, used to keep the piston assembly in a balanced state; the balanced state means that the piston assembly remains stationary relative to the valve body in the absence of fluid impact; A throttling channel connected to the valve port is formed between the piston assembly and the cavity wall of the inner cavity; wherein, when the piston assembly is in the equilibrium state, the ratio of the maximum flow area of ​​the throttling channel to the maximum flow area of ​​the valve port is ≤3 / 10.

2. The switching valve according to claim 1, characterized in that: When the piston assembly is in the balanced state, the throttling channel is formed between the inner circumferential surface of the valve port and the piston assembly.

3. The switching valve according to claim 2, characterized in that: The piston assembly has a second outer conical surface for sealingly cooperating with the valve port.

4. The switching valve according to claim 2, characterized in that: The piston assembly includes a first piston plate for extending into the valve port; The piston assembly further comprises a second piston plate and a third piston plate, wherein the second piston plate is sandwiched between the first piston plate and the third piston plate, and the second piston plate has a second outer conical surface which seals with the valve port.

5. The switching valve according to claim 1, characterized in that: The valve body comprises a first valve sleeve and a second valve sleeve arranged coaxially, wherein the second valve sleeve has the valve port; The throttling channel is formed between the inner circumferential surface of the first valve sleeve and the piston assembly and / or between the inner circumferential surface of the second valve sleeve and the piston assembly.

6. The switching valve according to claim 5, characterized in that: When the piston assembly is blocking the valve port, the flow area of ​​the throttling channel formed between the inner circumferential surface of the first valve sleeve and the piston assembly gradually decreases.

7. The switching valve according to claim 6, characterized in that: The inner circumferential surface of the first valve sleeve has an inner conical surface or the outer circumferential surface of the piston assembly has a first outer conical surface.

8. The switching valve according to claim 1, characterized in that: The valve port includes a first valve port and a second valve port, one end of the piston assembly is sealed with the first valve port, and the other end is sealed with the second valve port; the maximum flow area of ​​the first valve port is S11, and the maximum flow area of ​​the second valve port is S12; When the piston assembly is in the balanced state, the throttling channel includes a first throttling channel connected to the first valve port and a second throttling channel connected to the second valve port, the maximum flow area of ​​the first throttling channel is S21, and the maximum flow area of ​​the second throttling channel is S22; S21 / S11≤3 / 10, S22 / S12≤3 / 10.

9. The switching valve according to claim 8, characterized in that: The first throttling channel is located outside the first valve port, and the fluid flows to the first valve port through the first throttling channel; the second throttling channel is located outside the second valve port, and the fluid flows to the second valve port through the second throttling channel.

10. The switching valve according to claim 8 or 9, characterized in that: When the piston assembly is in the balanced state, the throttling channel also includes a third throttling channel connected to the first valve port and a fourth throttling channel connected to 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, part of the piston assembly extends into the first valve port, and the third throttling channel is formed between the hole wall of the first valve port, part of the piston assembly extends into the second valve port, and the fourth throttling channel is formed between the hole wall of the second valve port, and S31 / S11≤3 / 10, S32 / S12≤3 / 10.

11. The switching valve according to claim 1, characterized in that: The elastic member includes a first elastic portion and a second elastic portion, and the valve port includes a first valve port and a second valve port; A partition is provided in the inner cavity, and the partition separates the first valve port and the second valve port; The first elastic part and the second elastic part are respectively located on both sides of the partition part along the movement direction of the piston assembly, one end of the first elastic part abuts against the partition part, and the other end abuts against one end of the piston assembly; one end of the second elastic part abuts against the partition part, and the other end abuts against the other end of the piston assembly.

12. The switching valve according to claim 11, characterized in that: The partition part comprises a partition ring and a guide sleeve. The partition ring is fixedly connected to the cavity wall of the inner cavity and is connected to the outer periphery of the guide sleeve. The piston assembly is movably inserted into the guide sleeve.

13. The switching valve according to claim 1, characterized in that: The piston assembly comprises a plug rod and a piston, wherein the piston is connected to the plug rod and is used to block the valve port; The valve body has a guide portion, and the plug rod is in guiding cooperation with the guide portion.

14. The switching valve according to claim 13, characterized in that: The piston comprises a first piston and a second piston which are arranged at intervals along the axial direction of the plug rod, the valve port comprises a first valve port and a second valve port, the first piston is used to block or open the first valve port, and the second piston is used to block or open the second valve port; The plug rod has a guide section, which is located on a side of the first piston facing away from the second piston, and the guide section is in guiding cooperation with the guide portion.

15. A refrigeration system, characterized in that: Comprising the switching valve described in any one of claims 1-14.

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