A piston component

Abstract

A piston component comprises a first piston component, a second piston component, a first spring, one end of the first spring abutting against the first piston component, the other end of the first spring abutting against the second piston component, the second piston component being at least partially located in the first piston component; the second piston component and the first piston component are in sliding fit, the inner wall of the first piston component is smooth structure, the outer wall of the second piston component is smooth structure; the second piston component comprises a through-flow part, the first piston component comprises a through-flow part; the through-flow part of the second piston component is smaller than the through-flow part of the first piston component; the piston component can be actuated when the pressure difference between the two ends of the component in which the piston component is located is different, so as to realize the switching of flow path.

Description

Technical Field

[0001] This invention relates to the field of fluid control, and more specifically to a flow path switching device. Background Technology

[0002] Fluid systems require flow path control devices, such as the refrigerant flow path in a thermal management system. The refrigerant may undergo phase change, and the system may require different flow path states depending on the refrigerant's state. Summary of the Invention

[0003] To provide a control device for changing the flow path mode in a system according to the fluid state, the present invention provides the following piston component, which can be used in a flow path switching device:

[0004] A piston component includes a first piston component, a second piston component, and a first spring. One end of the first spring abuts against the first piston component, and the other end of the first spring abuts against the second piston component. The second piston component is located inside the first piston component or at least partially located inside the first piston component. The second piston component is slidably engaged with the first piston component. The inner wall of the first piston component includes a portion that slidably engages with the second piston component, and the outer wall of the second piston component includes a portion that slidably engages with the first piston component. The portion of the second piston component that slidably engages with the first piston component is defined as the outer wall portion, and the portion of the first piston component that slidably engages with the second piston component is defined as the inner wall portion. The inner wall portion of the first piston component has a smooth structure, and the outer wall portion of the second piston component has a smooth structure. The second piston component includes a flow passage portion, and the first piston component also includes a flow passage portion. The flow passage cross-sectional area of ​​the flow passage portion of the second piston component is smaller than the flow passage cross-sectional area of ​​the flow passage portion of the first piston component. The second piston component has two positions within the first piston component: a first position and a second position. In the first position, the elastic force of the first spring is greater than the elastic force in the second position.

[0005] The aforementioned piston assembly includes a first piston assembly, a second piston assembly, and a first spring. The second piston assembly is slidably fitted with the first piston assembly. The first and second piston assemblies are of different sizes, such that the second piston assembly is located within or at least mostly within the first piston assembly. Both the first and second piston assemblies have flow passages, and the flow passage cross-sectional area of ​​the flow passage in the second piston assembly is smaller than that of the flow passage in the first piston assembly. The flow resistance of the fluid flowing through the second piston assembly changes depending on the fluid state, enabling the piston assembly to actuate and switch the fluid flow path. Attached Figure Description

[0006] Figure 1A perspective view of one embodiment of the flow path switching device;

[0007] Figure 2 for Figure 1 A schematic diagram of one direction of the flow path switching device shown;

[0008] Figure 3 , Figure 4 for Figure 2 Cross-sectional schematic diagram of the two working states of the flow path switching device in the BB direction;

[0009] Figure 5 for Figure 2 Cross-sectional schematic diagram of the piston component of the flow path switching device in two working states;

[0010] Figure 6 for Figure 5 A three-dimensional schematic diagram of the piston component shown;

[0011] Figure 7 This is a three-dimensional schematic diagram of the second piston component of the aforementioned flow path switching device;

[0012] Figure 8 This is a three-dimensional schematic diagram of another piston component of the aforementioned flow path switching device;

[0013] Figure 9 for Figure 8 A schematic diagram of the piston assembly shown.

[0014] Figure 10 , Figure 11 for Figure 9 Cross-sectional schematic diagrams of the piston assembly in the DD direction showing two working states;

[0015] Figure 12 , Figure 13 This is a perspective view of a second embodiment of the flow path switching device;

[0016] Figure 14 for Figure 13 A cross-sectional schematic diagram of the flow path switching device shown.

[0017] In the picture:

[0018] 111 First cavity, 112 Second cavity, 113 Third cavity

[0019] 21 First interface section, 22 Second interface section, 231 Third interface section, 232 Auxiliary interface section, 241 Fourth interface section, 242 Fifth interface section,

[0020] 40 Main body part, 401 Main body part one, 402 Main body part two, 4021 Inner wall part, 4022, 4023 Sealing and mating parts, 41 Inner wall part, 42 First limiting part, 45 Second limiting part

[0021] 50 Piston assembly, 503 Third piston assembly, 5031 Third piston, 5032, 5033 Sealing parts, 51 First piston assembly, 510 Flow passage, 511 Outer wall, 5111 First guide, 5112 Second guide, 512 Sealing part, 513 Inner wall, 514 Limiting part, 515 Through hole, 516 Sealing mating part, 517 Spring abutment, 518 Limiting part, 52 Second piston assembly, 521 Outer wall, 522 Flared part, 523 Sealing part, 524 Inner wall, 525 Sealing element, 5251 Sealing part, 526 Stop, 527 Spring abutment, 528 Limiting part, 5281 Guide, 529 Sealing mating part, 53 Piston mating seat, 531 Sealing part, 537 Spring abutment, 539 Sealing mating part, 54 Fixing element, 561 First sealing element, 562 Second sealing element

[0022] 60. Cover, 61. Bending hole, 62. Sealing mating part.

[0023] 701 Second spring, 702 First spring, 703 Third spring, 71, 72, 73 Sealing rings Detailed Implementation

[0024] The technical solution will be described below with reference to specific implementation methods. Figures 1-6 , Figure 1 This is a perspective view of one embodiment of the flow path switching device. Figure 2 This is a schematic diagram of one direction of the flow path switching device. Figure 3 , is a cross-sectional schematic diagram of the first working state of the flow path switching device in the BB direction. Figure 4 This is a cross-sectional schematic diagram of the second operating state of the flow path switching device along the BB direction. Figure 5 This is a cross-sectional schematic diagram showing two operating states of the piston component of the flow path switching device. Figure 6 for Figure 5 A three-dimensional schematic diagram of the piston assembly shown. Figure 7 This is a three-dimensional schematic diagram of the second piston component of the flow path switching device.

[0025] The flow path switching device includes a main body 40, a piston component 50, a cover 60, and a second spring 701. The cover 60 is fixed or limited to the main body 40, such as by threaded fixing and sealing with a sealing ring 71, or by welding the cover 60 to the main body 40, or by limiting it with a snap ring. One end of the second spring 701 abuts against the bottom wall of the cavity of the main body, i.e., the second limiting part 45, and the other end of the second spring 701 abuts against the spring abutment part 517 of the piston component 50. The abutment can be direct or indirect. The piston component 50 can slide within the cavity of the main body 40. The inner cavity of the main body has a first limiting part 42 on the side relatively close to the third interface part. In this embodiment, the first limiting part 42 is a stepped part. The sliding stroke S of the piston component 50 is defined. In the first working state, refer to... Figure 3 and Figure 4 In the second operating state, the limiting portion 514 of the piston component 50 abuts against the first limiting portion 42 of the body portion. The sealing portion 512 of the piston component 50 abuts against and seals with the sealing mating portion 62 of the cover 60. The piston component 50 includes a first piston component 51 and a second piston component 52, which slides against the first piston component 51. The sliding stroke S1 of the second piston component 52 relative to the first piston component is defined. The portion of the outer wall of the piston component that slides against the body portion is defined as the outer wall portion, and the portion of the inner wall of the body portion that slides against the piston component is defined as the inner wall portion. Similarly, the portion of the outer wall of the second piston component that slides against the first piston component is defined as the outer wall portion, and the portion of the inner wall of the first piston component that slides against the second piston component is defined as the inner wall portion. The position of the second piston component within the first piston component in the first operating state is defined as the first position, and the position of the second piston component within the first piston component in the second operating state is defined as the second position.

[0026] The inner wall portion 41 of the body portion slides into contact with the outer wall portion 511 of the first piston component 51. Specifically, the inner wall portion 41 of the body portion in the sliding contact portion is 0.025-0.15 mm larger than the outer wall portion 511 of the first piston component 51. For better fit, the inner wall portion 41 of the body portion is 0.03-0.07 mm larger than the outer wall portion 511 of either the piston component 50 or the first piston component 51. Alternatively, the inner diameter of the smallest portion of the inner wall portion 41 of the body portion in the sliding contact portion is 0.025-0.15 mm larger than the largest portion of the outer wall portion 511 of the first piston component 51, or even controlled within 0.03-0.07 mm, to ensure better fit. Furthermore, both the inner wall portion 41 of the body portion and the outer wall portion 511 of the piston component 50 in the sliding contact portion are relatively smooth. The first piston component 51 includes a first piston 5100. To ensure better sealing after the piston component mates with the body, the first piston component 51 may also include a sealing element 72. In this case, the sealing element 72 can be disposed in a groove on the outer wall of the first piston. Alternatively, the sealing element can be disposed in a groove on the inner wall of the body, with the sealing element in a compressed state, thereby providing a relatively better seal between the inner wall of the body and the outer wall of the piston component 50. In this embodiment, the outer wall of the first piston serves as the outer wall of the first piston component 51 and is also the outer wall of the piston component.

[0027] The first piston component 51 includes a piston mating seat 53, which is fixed or limited to the first piston 5100. As shown in the figure, the piston mating seat 53 and the first piston 5100 are sealed by threaded engagement with a sealing element 73. Alternatively, they can be fixed by welding or limited by a snap ring.

[0028] Piston component 50 includes a second piston component 52. In this embodiment, the second piston component 52 is located within the first piston component 51 and is slidably disposed within the inner cavity of the first piston component 51. The first piston component 51 has a limiting portion that restricts the sliding stroke of the second piston component 52. Additionally, the second piston component 52 may partially extend out of the first piston component, but at least partially is slidably disposed within the inner cavity of the first piston component 51. The inner wall portion 513 of the first piston and the outer wall portion 521 of the second piston component 52 are in sliding engagement. In this configuration, the inner wall portion 513 of the first piston in the sliding fit is 0.025-0.15 mm larger than the outer wall portion 521 of the second piston component 52. For better fit, the inner wall portion 513 of the first piston is 0.03-0.07 mm larger than the outer wall portion 521 of the second piston component 52 or the second piston 520. Alternatively, the inner diameter of the smallest part of the inner wall portion 513 of the sliding fit of the first piston is 0.025-0.15 mm larger than the largest part of the outer wall portion 521 of the second piston component 52. For better fit, the inner diameter of the smallest part of the inner wall portion 513 is 0.03-0.07 mm larger than the largest part of the outer wall portion 521 of the second piston component 52. Both the inner wall portion 513 and the outer wall portion 521 of the sliding fit are relatively smooth. The diameter of the outer wall portion 511 of the first piston component is between 1.35 and 1.7 times the diameter of the outer wall portion 521 of the second piston component. To improve the performance of the piston component, the diameter of the outer wall portion 511 of the first piston component is between 1.45 and 1.65 times the diameter of the outer wall portion 521 of the second piston component.

[0029] The second piston component 52 includes a second piston 520, a seal 525, and a stop 526. The seal 525 has an annular structure and is made of a plastic material such as polytetrafluoroethylene or high-strength rubber that facilitates sealing. The stop is used to limit or fix the seal 525. The seal 525 and the stop 526 are sleeved on the second piston 520. Specifically, the second piston 520 has a stepped portion. The stop 526 is limited to the inner step 5202, and the seal 525 is limited to the outer step 5201. The seal 525 faces inward and... The outer step 5201 abuts against each other, and the inner side of the seal 525 facing outward is pressed or abutted by the stop to limit it. The sealing part 5251 of the seal 525 facing outward is used to cooperate with the sealing mating part 516 of the first piston to seal and limit it. The seal 525 is less than or equal to the outer wall part of the second piston for sliding mating. The stop is smaller than the seal of the second piston component. The seal 525 and the stop 526 are fixed or limited by partially widening the protrusion of the second piston to form a widened part 522 or by partially flanging the protrusion.

[0030] A first spring 702 is provided between the second piston component 52 and the first piston component 51. One end of the first spring 702 abuts against the spring abutment portion 537 of the first piston component 51, and the other end of the first spring 702 abuts against the spring abutment portion 527 of the second piston component 52. The spring abutment portion 537 of the first piston component 51 is located in a recess, and the spring abutment portion 527 of the second piston component 52 is also located in a recess. In other words, the spring abutment portion 527 of the second piston component 52 is located inside the outer wall portion of the second piston component 52 for sliding engagement. In this way, the second spring will not increase the length of the piston component too much, which is conducive to miniaturization. The abutment portion 537 of the first piston component 51 can be directly or indirectly abutted.

[0031] The second piston component 52 has a sealing part 523 and a limiting part 528 on the side opposite to the seal 525. The sealing part 523 of the second piston component 52 cooperates with the sealing mating part 539 of the first piston component for sealing, and the sealing mating part 529 of the second piston component 52 cooperates with the sealing part 531 of the first piston component for sealing. These two sets of sealing mating allow the inner and outer sides of the second piston to be sealed simultaneously. At least one of these two sets of sealing mating is a soft seal, such as a structure that includes a seal made of rubber. The piston component is limited in the first working state by the contact of these two sets of sealing mating. In addition, when both sets are soft seals, a limiting part can be provided for further limiting. This helps to control the compression of the soft seal component during sealing and ensure its service life. The scheme illustrated in this embodiment adopts a soft seal structure. In addition, one of the sealing matings can be a hard seal, in which case this set does not need a seal or a limiting structure.

[0032] The flow path switching device includes a first interface portion 21, a second interface portion 22, and a third interface portion 231. In the axial direction, the second interface portion 22 is located between the first interface portion 21 and the third interface portion 231. The portion of the cavity within the flow path switching device that communicates with the first interface portion 21 is defined as the first cavity 111, and the portion of the cavity within the flow path switching device that communicates with the third interface portion 231 is defined as the third cavity 113. The cavity within the piston component of the flow path switching device in the second working state, after the flow passage portion A of the second piston component and before the flow passage portion C of the first piston component, is defined as the second cavity 112. It may also include an auxiliary interface portion 232, which communicates with the third interface portion 231. The auxiliary interface portion 232 may be absent. A second spring 701 is relatively close to the third interface portion, and at least a portion of the second spring 701 is located in the third cavity 113 where the auxiliary interface portion 232 communicates with the third interface portion 231. The first spring is located inside the piston assembly. The first piston assembly abuts against the first spring 702 and the second spring 701 simultaneously, but the two springs exert opposite forces on the first piston assembly.

[0033] Both the first piston component and the second piston component of the flow path switching device have flow sections for fluid passage. The smallest cross-sectional area of ​​the flow section in the first piston component is defined as the flow passage section, the smallest cross-sectional area of ​​the flow section in the second piston component is defined as the flow passage section, and the smallest cross-sectional area of ​​the flow section in the first interface 21 is defined as the flow passage section. The cross-sectional area of ​​the flow passage section in the second piston component is smaller than the cross-sectional area of ​​the flow passage section in the first interface 21, and the cross-sectional area of ​​the flow passage section in the second piston component is smaller than the cross-sectional area of ​​the flow passage section in the first piston component. Furthermore, the cross-sectional area of ​​the flow passage section in the second piston component of the flow path switching device is smaller than the cross-sectional area of ​​other parts of the flow path switching device. Specifically, the second piston component has a through hole 25 as a flow passage A. The through hole 25 can be a straight hole, a stepped hole, or an oblique hole. The smallest part of the through hole 25 is the flow passage A. The first piston component has a flow passage 510. In this embodiment, the flow passage 510 of the first piston component is disposed on the piston mating seat 53. The flow passage 510 includes multiple through holes 515, specifically 3, 4, 5, or 6. Two or more through holes 515 can be provided as flow passage C as needed. The through holes 515 are disposed at the location of the groove. The through holes 515 are a certain distance from the center of the piston mating seat 53 and a certain distance from the outer edge of the piston mating seat 53. The through holes 515 can be circular; to increase the flow passage cross-sectional area of ​​the flow passage, the through holes 515 can be non-circular. There is a connecting part 519 between adjacent through holes 515. In this embodiment, the connecting part 519 serves as a spring abutment or as part of a spring abutment.

[0034] The flow passage cross-sectional area of ​​the flow passage section A of the second piston component is between 0.2 and 0.7 times that of the flow passage cross-sectional area of ​​the flow passage section B of the first interface section 21, and the flow passage cross-sectional area of ​​the flow passage section A of the second piston component is between 0.3 and 0.7 times that of the flow passage cross-sectional area of ​​the flow passage section C of the first piston component; the flow passage cross-sectional area of ​​the flow passage section A of the second piston component can be between 0.3 and 0.6 times that of the flow passage cross-sectional area of ​​the flow passage section B of the first interface section 21, and even between 0.4 and 0.5 times that of the flow passage cross-sectional area of ​​the flow passage section B of the first interface section 21. In a specific embodiment, the flow passage cross-sectional area of ​​the flow passage section A of the second piston component is 0.5 times that of the flow passage cross-sectional area of ​​the flow passage section B of the first interface section 21, and the flow passage cross-sectional area of ​​the flow passage section A of the second piston component is less than 0.6 times that of the flow passage cross-sectional area of ​​the flow passage section C of the first piston component. This can be determined based on the system's compatibility and the fluid's properties.

[0035] The flow path switching device can be used in systems where the fluid state changes significantly, such as refrigeration systems using refrigerant. Refrigerant undergoes phase changes under different operating conditions, existing in liquid, gas, or two-phase (liquid-vapor) states. Initially, due to the spring force, the piston component is relatively close to the first chamber, i.e., close to or in the second operating state. Under different fluid states, because the flow passage of the second piston component is relatively small, the flow resistance through the flow path switching device varies, resulting in different pressures between the first and second chambers. A pressure difference is generated between the first and second chambers. When the pressure difference is large, it overcomes the spring force of the first spring, causing the second piston component to slide to the left as shown in the diagram. The flow path switching device achieves flow path switching through the pressure difference and the spring. The piston component's stroke is greater than or equal to 0.5 times the diameter of the first interface. To reduce fluid pressure loss, when the interface cross-section is circular, the piston component's stroke is between 0.7 and 1.1 times the diameter of the first interface, or even approximately the same.

[0036] In the first working state, the first interface 21 is connected to the second interface 22, suitable for a two-phase state where the fluid is gas or mostly gaseous. Because the flow passage A of the second piston component is relatively small, there is relatively large resistance to fluid flow, causing the fluid pressure in the second chamber 112 to be less than the fluid pressure in the first chamber 111, and the fluid pressure in the third chamber 113 to be less than the fluid pressure in the first chamber 111. When the pressure difference between the two ends of the second piston component creates a pressure differential force greater than the force of the first spring, the second piston component overcomes the force of the first spring and moves towards the third interface until it comes into contact with and relatively seals against the first piston component. At this point, one end of the piston component is at a relatively high pressure, and the other end is connected to the relatively low-pressure side of the system. A relatively large pressure difference is formed between the two ends of the piston component. The pressure differential force created by this pressure difference is greater than the force of the second spring, causing the piston component to overcome the force of the second spring and move towards the third interface, that is, to move the piston component towards the left side of the diagram, until it reaches the third interface. Figure 3In the state shown, the second piston component is in contact with the first piston component, and the second chamber no longer exists. Fluid flows into the flow path switching device through the first interface 21 to the first chamber 111, and then flows out through the second interface 22. At this time, the limiting part 514 of the piston component 50 abuts against the first limiting part 42 of the body part, and the second spring is in a strong compression state, that is, the force exerted by the second spring on the piston component is greater than the force exerted by the second spring on the piston component in the second working state. The outer wall of the piston component and the inner wall of the body part can be well sealed due to the sealing part 72. The sealing part 523 of the second piston component 52 is sealed with the sealing mating part 539 of the first piston component, and the sealing mating part 529 of the second piston component 52 is sealed with the sealing part 531 of the first piston component. The first spring is in a strong compression state, that is, the force exerted by the first spring on the second piston component is greater than the force exerted by the first spring on the second piston component in the second working state. The fluid entering from the first interface will basically not flow out from the third interface 231 through the piston component. The third interface 231 is connected to the relatively low pressure end of the system. In this way, a relatively large pressure difference is maintained on both sides of the piston component, and this working state is maintained.

[0037] In the second working state, the first interface 21 is connected to the third interface 231 and the auxiliary interface 232, suitable for a two-phase state where the fluid is liquid or relatively liquid. Thus, in the initial state, the resistance of the fluid passing through the flow passage A of the second piston component is relatively small, the pressure difference between the first and second chambers is relatively small, the force of the first spring is relatively greater than the force of the pressure difference across the two ends of the second piston component, the outer wall of the second piston component is larger than the aperture of the sealing mating part 516 on the side of the first piston closer to the cover, and the outer diameter of the seal of the second piston component is larger than the aperture of the sealing mating part of the first piston. Figure 4 At this time, the sealing part 512 of the piston component 50 abuts against and seals with the sealing mating part 62 of the cover. The sealing part 5251 of the sealing element 525 of the second piston component seals with the sealing mating part 516 of the first piston, sealing and limiting the movement. The first spring is in a relatively small compression state, and the second spring is in a relatively small compression state. Fluid flows into the flow path switching device through the first interface part 21 to the first chamber 111, through the flow passage A of the second piston component to the second chamber 112, and then through the flow passage C of the first piston component to the third chamber 113, and flows out from the third interface part 231 and / or the auxiliary interface part 232. The stroke of the second piston component relative to the first piston component is between 0.6 and 1 times the stroke of the piston component relative to the body part, thus achieving relative miniaturization.

[0038] The cover 60 extends into the inner cavity of the main body, and the depth of the cover 60 in the axial direction exceeds the first interface portion 21. A portion of the cover is located inside the first interface portion. The cover and the main body include two sets of sealing fits. In the axial direction, one set of sealing fits is located on the outward side of the first interface portion, and the other set of sealing fits is located on the inward side of the first interface portion. Specifically, the sealing fit between the two sets is achieved by providing sealing elements 71 and 74. The cover 60 has a bending hole 61, which includes an axial hole and a transverse hole. The axial hole and the transverse hole communicate with each other and are also connected to the first interface portion 21.

[0039] In addition, the flow path switching device can also be controlled by the system. For example, when the flow path switching device needs to maintain the initial state, i.e. the second working state, the system pressure can be increased slowly. When the flow path switching device needs to switch to the first working state, the system pressure can be increased relatively quickly, which can be combined with the fluid state to achieve the desired effect.

[0040] In the above embodiments, the piston component and the body part are sealed by a sealing element while sliding together. In applications with relatively low requirements, a sealing element may not be required, and the fit clearance between the piston component and the body part can be controlled. For example, the clearance on one side can be between 0.015-0.03 mm, i.e., the clearance on both sides can be between 0.03-0.07 mm. The inner wall of the body part is 0.03-0.07 mm larger than the outer wall of the piston component. (See reference...) Figures 8-11 , Figure 8 This is a three-dimensional schematic diagram of another piston component in the flow path switching device. Figure 9 for Figure 8 A schematic diagram of the piston assembly shown. Figure 10 , Figure 11 for Figure 9 The diagram shows cross-sectional views of the piston assembly in the DD direction for two different operating states. Other structures of the flow path switching device can be referenced from the above embodiment.

[0041] The piston assembly includes a first piston assembly 51, a second piston assembly 52, and a first spring 702. The outer wall portion 511 of the first piston assembly 51 has a smooth structure for sliding engagement with the inner wall portion of the main body. Guide portions are respectively provided at both ends of the outer wall portion of the first piston assembly 51: a first guide portion 5111 and a second guide portion 5112, located on both sides of the outer wall portion of the piston assembly for sliding engagement. These two guide portions can also be used for the aforementioned first piston assembly. The outer wall portion 511 of the first piston assembly 51 in the sliding engagement portion is 0.03-0.07 mm smaller than the inner wall portion 41 of the main body; or, the inner diameter of the smallest part of the inner wall portion 41 of the sliding engagement portion of the main body is 0.03-0.07 mm larger than the largest part of the outer wall portion 511 of the first piston assembly 51. In this embodiment, the outer wall portion 511 of the first piston 5100' serves as the outer wall portion of the first piston assembly 51 and also as the outer wall portion of the piston assembly.

[0042] The first piston component 51 includes a piston mating seat 53. The piston mating seat 53 can be fixed or limited to the first piston 5100'. As shown in the figure, the piston mating seat 53 and the first piston 5100' are fixed by threads. Alternatively, it can be fixed in a relatively sealed manner with a sealing element. It can also be fixed by welding or limited by a snap ring.

[0043] In this embodiment, the second piston component 52 is located inside the first piston component 51, and the second piston component 52 is slidably disposed within the inner cavity of the first piston component 51. Additionally, the second piston component 52 may partially extend out of the first piston component, but most of it is slidably disposed within the inner cavity of the first piston component 51. The inner wall portion 513 of the first piston component, i.e., the inner wall portion 513 of the first piston, is in sliding engagement with the outer wall portion 521 of the second piston component 52. In this configuration, the inner wall portion 513 of the first piston in the sliding fit is 0.025-0.15 mm larger than the outer wall portion 521 of the second piston component 52. For better fit, the inner wall portion 513 of the first piston is 0.03-0.07 mm larger than the outer wall portion 521 of the second piston component 52 (i.e., the second piston 520). Alternatively, the inner diameter of the smallest part of the inner wall portion 513 of the sliding fit of the first piston is 0.025-0.15 mm larger than the largest part of the outer wall portion 521 of the second piston component 52. For better fit, the inner diameter of the smallest part of the inner wall portion 513 is 0.03-0.07 mm larger than the largest part of the outer wall portion 521 of the second piston component 52. Both the inner wall portion 513 and the outer wall portion 521 of the sliding fit are relatively smooth.

[0044] The second piston component 52 includes a second piston 520, a seal 525, and a stop 526. The seal 525 has an annular structure and is made of a plastic material such as polytetrafluoroethylene or a high-hardness rubber that facilitates sealing. The stop is used to limit or fix the seal 525. The seal 525 and the stop 526 are sleeved on the second piston 520. Specifically, the second piston 520 has a stepped portion. In the axial direction, the stop 526 is limited to the inner step 5202, and the seal 525 is limited to the outer step 5201. The seal 525 faces inward. One side abuts against the outer step 5201. The inner side of the outward-facing side of the seal 525 is pressed or limited by a stop. The outer sealing portion 5251 of the seal 525 is used to cooperate with the sealing mating portion 516 of the first piston for sealing and limiting. The seal 525 is smaller than or equal to the outer wall portion of the second piston for sliding cooperation. The stop is smaller than the seal of the second piston component. The seal 525 and the stop 526 are fixed or limited by partially flaring the protrusion of the second piston to form a flared portion 522 or by partially flanging the protrusion. The seal 525 can also be replaced by a relatively soft sealing ring, which is located at the corresponding part of the second piston. Alternatively, a hard seal structure can be used, with the sealing portion or sealing mating portion directly set on the second piston to cooperate with the first piston component to achieve relative sealing.

[0045] A first spring 702 is provided between the second piston component 52 and the first piston component 51. One end of the first spring 702 abuts against the spring abutment portion 537 of the first piston component 51, and the other end of the first spring 702 abuts against the spring abutment portion 527 of the second piston component 52. The spring abutment portion 537 of the first piston component 51 is located in a recess, and the spring abutment portion 527 of the second piston component 52 is also located in a recess. In other words, the spring abutment portion 527 of the second piston component 52 is located inside the outer wall portion of the second piston component 52 used for sliding engagement. Alternatively, the spring abutment portion 527 of the second piston component 52 is closer to the seal 525 than the limiting portion 528 used for engagement and limiting with the piston mating seat of the first piston component. In this way, the second spring will not increase the length of the piston component too much, which is beneficial for miniaturization. The abutment with the spring abutment portion 537 of the first piston component 51 can be direct or indirect.

[0046] The piston mating seat of the first piston component is provided with a second sealing element 562. The second sealing element 562 is limited by a fixing element 54. The fixing element 54 can be an integral structure with the piston mating seat, formed by riveting or other methods, or it can be assembled separately, such as by tight fitting or threaded connection, to limit the second sealing element 562. The second sealing element 562 is larger than the outer wall of the piston mating seat where the second sealing element is provided, that is, the outer walls on both sides of the second sealing element. In other words, part of the second sealing element is exposed on the outer wall of the piston mating seat where the second sealing element is provided, thus forming a sealing part of the first piston component. Correspondingly, part of the inner wall of the second piston component 52 serves as a sealing mating part. The structure of the second piston component 52 relative to the side closer to the piston mating seat is different from that of the first embodiment. The inner wall of the first piston component is provided with a groove 5131. The first sealing element 561 is provided in the groove 5131. At least most of the first sealing element 561 is located in the groove, with part of it exposed on the inner wall 513 of the first piston, thus forming a sealing part on the inner wall of the first piston component. Correspondingly, the outer wall of the second piston component 52 serves as a sealing mating part. This creates two sets of sealing fits between the second piston component and the first piston component, ensuring relative sealing on both the inner and outer sides of the second piston component in the first position. When the second piston component 52 slides, a portion of the guide portion 5281 is smaller than the first seal 561. In the first operating state, the limiting portion 528 of the second piston component abuts against the limiting portion 518 of the first piston component. At this time, the first seal 561 engages with the outer wall of the second piston component to achieve relative sealing, while the second seal 562 of the first piston component contacts the inner wall 524 of the second piston component to achieve relative sealing. Similarly, a guide portion 5241 is also provided on the inner wall of the second piston component adjacent to the inner wall 524. A portion of the guide portion 5241 is larger than the second seal 562, and the guide portion 5241 has a smooth transition. A stepped portion is provided on the outer side of the guide portion 5241 as a spring abutment portion 527. The spring abutment portion 527 is axially closer to the seal 525 on the other side than the limiting portion 528. To achieve a relatively good sealing effect, the first and second seals are made of soft material with a certain degree of elasticity; a concave-convex structure can be provided on the outward side, and / or on the inward side; to improve elasticity, concave-convex structures can also be provided on the other two sides of the first and second seals.

[0047] The axial movement of the second piston component within the cavity of the first piston component is achieved through a limiting part. The sealing between the second and first piston components in the first operating state is achieved through the engagement of the bottom wall of the groove of the first seal contacting the outer wall of the second piston, and the engagement of the bottom wall of the recess of the piston mating seat of the second seal contacting the inner wall of the second piston; that is, the inner and outer sides of the second piston component achieve relative sealing simultaneously. The sealing between the second and first piston components in the second operating state is achieved through the engagement of the seal and the sealing mating part. This piston component is applicable to the first embodiment and similar flow path switching devices. The rest can refer to the above embodiment, and some structures and functions of these two can be combined and replaced.

[0048] In addition, the flow path switching device can also be other structures, such as Figures 12-14 , Figure 12 , Figure 13 This is a perspective view of a second embodiment of the flow path switching device. Figure 14 This is a cross-sectional schematic diagram of the flow path switching device, which is in its first working state at this time.

[0049] The flow path switching device includes a main body 40, a piston component 50, a cover 60, a second spring 701, a third spring 703, and a third piston component 503. The main body 40 includes a first body 401 and a second body 402, which can be an integral structure or separate and assembled. The cover 60 is fixed or limited to the first body 401, such as by threaded fixing, welding fixing, or limiting by a snap ring. The structure and operation of the cover 60, the first body 401, the piston component, and the second spring 701 are as described in the above embodiment. The main difference in this embodiment is that it has a second body 402, a third piston component 503, and a third spring 703. One end of the third spring 703 abuts against the limiting part 4025 of the second body, and the other end of the third spring 703 abuts against the spring abutting part 5035 of the third piston component 503. The abutting can be direct or indirect. The third spring can also be other elastic elements, or it can be omitted. The third piston component is pushed by the pressure difference on both sides.

[0050] The flow path switching device has a first interface section 21, a second interface section 22, a third interface section 231, an auxiliary interface section 232, a fourth interface section 241, and a fifth interface section 242. The first interface section 21, the second interface section 22, the third interface section 231, and the auxiliary interface section 232 are located in the first body section, and their communication and operation are as described in the above embodiment. The fourth interface section 241 and the fifth interface section 242 are located in the second body section. The second body section also has an interface section 5030, which is connected and communicates with the second interface section 22. The third piston component 503 can slide within a certain stroke in the inner cavity of the second body section 402 under the action of pressure differential force and spring force. The cavity of the third piston component 503 in the inner cavity of the second body part is defined as the fourth cavity 114 on the side closer to the first body part, and the cavity of the third piston component 503 in the inner cavity of the second body part is defined as the fifth cavity 115 on the side relatively away from the first body part. The fourth cavity 114 and the fifth cavity 115 are not fixed, but change with the movement of the third piston component. When the third piston component 503 is close to the first part of the main body, the sealing part 5033 of the third piston component contacts and seals with the sealing mating part 4023 of the second part of the main body. The fifth cavity 115 in the second part of the main body is not connected to the second interface part 22, and the fourth interface part 241 and the fifth interface part 242 are connected through the fifth cavity 115 in the second part of the main body. When the third piston component 503 is away from the first part of the main body, the sealing part 5032 of the third piston component contacts and seals with the sealing mating part 4022 of the second part of the main body. The fifth cavity 115 in the second part of the main body is not connected to the fourth interface part 241, and the fourth interface part 241 and the second interface part 22 are connected through the fourth cavity 114 in the second part of the main body, and are also connected to the first interface part.

[0051] The third piston component 503 is located within the second body part 402, and is slidably disposed within the inner cavity of the second body part 402. The outer wall portion of the third piston component is in sliding engagement with the inner wall portion 4021 of the second body part. Specifically, the outer wall portion of the third piston component in the sliding engagement is 0.025-0.15 mm smaller than the inner wall portion 4021 of the second body part; for better fit, the outer wall portion of the third piston component in the sliding engagement is 0.03-0.07 mm smaller than the inner wall portion 4021 of the second body part.

[0052] In the first working state, the first interface 21 is connected to the second interface 22 and the first interface 21 is connected to the fourth interface 241, which is suitable for a liquid-liquid two-phase state where the fluid is gas or mostly gas. The flow passage A of the second piston component is relatively small. In the initial state, there will be relatively large resistance to the fluid flow, making the fluid pressure in the second chamber 112 less than the fluid pressure in the first chamber 111, and the fluid pressure in the third chamber 113 less than the fluid pressure in the first chamber 111. There is a pressure difference between the left and right sides of the piston component. The pressure difference between the two ends of the second piston component gives the second piston component a pressure difference force greater than the force of the first spring, causing the second piston component to overcome the force of the first spring and move towards the third interface until the second piston component abuts against the first piston component and is relatively sealed. At this time, one end of the piston component is relatively high pressure, and the other end is connected to the relatively low pressure side of the system. A relatively large pressure difference is formed between the two ends of the piston component. The pressure difference force acts on the piston component and has a pressure difference force in the axial direction towards the third interface, which overcomes the force of the second spring and causes the piston component to move towards the second limiting part until the piston component abuts against a part of the main body. At this time, the second chamber no longer exists or is basically non-existent. The fluid flows into the flow path switching device through the first interface section 21 to the first cavity 111, then through the second interface section 22, through the fourth cavity 114 of the second body section, and out from the fourth interface section.

[0053] In the second working state, the piston component and the main body are basically the same as in the above embodiment. The first interface 21 is connected to the third interface 231 and the auxiliary interface 232, which is suitable for a liquid or a liquid-liquid two-phase state where the fluid is liquid or relatively liquid. In this way, the resistance of the fluid passing through the flow passage A of the second piston component is relatively small, and the spring force of the first spring is relatively greater than the pressure difference force at both ends of the second piston component. At this time, the sealing part 512 of the piston component 50 abuts against and seals with the sealing mating part 62 of the cover. The sealing part 5251 of the sealing element 525 of the second piston component seals with the sealing mating part 516 of the first piston seals and seals and limits the movement. The first spring is in a relatively small compression state, and the second spring is in a relatively small compression state. The fluid flows into the flow path switching device through the first interface 21 to the first chamber 111, through the flow passage A of the second piston component to the second chamber 112, and then through the flow passage C of the first piston component to the third chamber 113, and flows out from the third interface 231 and / or the auxiliary interface 232. The stroke of the second piston component relative to the first piston component is between 0.6 and 1 times the stroke of the piston component relative to the body, thus enabling relative miniaturization. The state of the third piston component is related to the fluid state of the part of the system connected to the fourth or fifth interface.

[0054] It should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. They cannot be used as a limitation on the scope of protection of the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that those skilled in the art can still modify, combine or make equivalent substitutions to the present invention. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of this solution.

Claims

1. A piston component, comprising a first piston component, a second piston component, and a first spring, one end of the first spring abutting against the first piston component, the other end of the first spring abutting against the second piston component, the second piston component being located within the first piston component or at least partially located within the first piston component; the second piston component slidingly engaging with the first piston component, the inner wall of the first piston component including a portion slidingly engaging with the second piston component, the outer wall of the second piston component including a portion slidingly engaging with the first piston component, the portion of the second piston component for slidingly engaging with the first piston component defined as the outer wall portion, the portion of the first piston component for slidingly engaging with the second piston component defined as the inner wall portion, the inner wall portion of the first piston component having a smooth structure, and the outer wall portion of the second piston component having a smooth structure; the second piston component including a flow passage portion, the first piston component including a flow passage portion; the flow passage cross-sectional area of ​​the flow passage portion of the second piston component being smaller than the flow passage cross-sectional area of ​​the flow passage portion of the first piston component; the second piston component having two positions within the first piston component: a first position and a second position, the elastic force of the first spring being greater in the first position than in the second position; When the second piston component is in the first position, its outer wall is provided with a sealing part or a sealing mating part, and the first piston component is provided with a sealing mating part or a sealing part that corresponds to and seals with the outer wall of the second piston component; the inner wall of the second piston component is provided with a sealing mating part or a sealing part, and the first piston component includes a piston mating seat, which is provided with a sealing part or a sealing mating part that corresponds to and seals with the inner wall of the second piston component; at least one of the two sealing parts includes a sealing element or sealing part made of a soft material; The first piston component has a sealing mating part on the side opposite to the flow passage of the first piston component, and the second piston component has a sealing part on the side relatively far away from the flow passage of the first piston component. When the second piston component is in the second position, the sealing part of the second piston component can cooperate with the sealing mating part of the first piston component to seal; or, the first piston component has a sealing part on the side opposite to the flow passage of the first piston component, and the second piston component has a sealing mating part on the side relatively far away from the flow passage of the first piston component. When the second piston component is in the second position, the sealing mating part of the second piston component can cooperate with the sealing part of the first piston component to seal.

2. The piston component according to claim 1, wherein the first piston component includes a first piston, and the piston mating seat is fixed to the first piston; a flow passage of the first piston component is disposed on the piston mating seat, the flow passage of the first piston component includes two or more through holes, the through holes are at a certain distance from the center of the piston mating seat, the through holes are at a certain distance from the outer edge of the piston mating seat, and the cross-section of the through holes is circular or non-circular; a connecting portion is provided between adjacent through holes; and the side of the piston mating seat facing the second piston component abuts against the first spring.

3. The piston component according to claim 2, wherein the piston mating seat includes a limiting portion for limiting the second piston component, the second piston component having a limiting portion that mates with the limiting portion of the piston mating seat; when the second piston component is in a first position, the limiting portion of the piston mating seat abuts against the limiting portion of the second piston component; the piston mating seat has a recess facing the inner cavity of the first piston component, the piston mating seat includes a spring abutting portion abutting against one end of the first spring, the spring abutting portion being located in the recess; the second piston component includes a spring abutting portion abutting against the other end of the first spring, the axial distance between the spring abutting portion of the second piston component and the spring abutting portion of the piston mating seat is greater than the axial distance between the limiting portion of the second piston component and the spring abutting portion of the piston mating seat.

4. The piston component according to claim 1, wherein the sealing mating portion of the first piston component is disposed on one side of the flow passage portion of the first piston component, and the sealing portion of the second piston component is disposed on the side relatively close to the flow passage portion of the first piston component, and the sealing portion of the second piston component and the sealing mating portion of the first piston component can cooperate to seal; or the sealing portion of the first piston component is disposed on the side relatively close to the flow passage portion of the first piston component, and the sealing mating portion of the second piston component is disposed on the side relatively close to the flow passage portion of the first piston component, and the sealing mating portion of the second piston component and the sealing portion of the first piston component can cooperate to seal.

5. The piston component according to any one of claims 1-4, wherein the outer wall of the first piston component is provided with a guide portion, the guide portion is located on at least one side of the outer wall portion, and the guide portion is connected to the outer wall portion; the outer wall of the second piston component is provided with a guide portion.

6. The piston component according to any one of claims 1-4, wherein the flow passage cross-sectional area of ​​the flow passage portion (A) of the second piston component is between 0.3 and 0.7 times the flow passage cross-sectional area of ​​the flow passage portion (C) of the first piston component; the inner wall portion of the first piston component is 0.025-0.15 mm larger than the outer wall portion of the second piston component; and the diameter of the outer wall portion of the first piston component is between 1.35 and 1.7 times the diameter of the outer wall portion of the second piston component.

7. The piston component according to claim 5, wherein the flow passage cross-sectional area of ​​the flow passage portion (A) of the second piston component is between 0.3 and 0.7 times the flow passage cross-sectional area of ​​the flow passage portion (C) of the first piston component; the inner wall portion of the first piston component is 0.025-0.15 mm larger than the outer wall portion of the second piston component; and the diameter of the outer wall portion of the first piston component is between 1.35 and 1.7 times the diameter of the outer wall portion of the second piston component.

8. The piston component according to any one of claims 1-3, wherein the flow passage cross-sectional area of ​​the flow passage portion (A) of the second piston component is between 0.4 and 0.6 times the flow passage cross-sectional area of ​​the flow passage portion (C) of the first piston component, the inner wall portion of the first piston component is 0.03-0.07 mm larger than the outer wall portion of the second piston component, and the diameter of the outer wall portion of the first piston component is between 1.45 and 1.65 times the diameter of the outer wall portion of the second piston component.

9. The piston component according to claim 4, wherein the flow passage cross-sectional area of ​​the flow passage portion (A) of the second piston component is between 0.4 and 0.6 times the flow passage cross-sectional area of ​​the flow passage portion (C) of the first piston component, the inner wall portion of the first piston component is 0.03-0.07 mm larger than the outer wall portion of the second piston component, and the diameter of the outer wall portion of the first piston component is between 1.45 and 1.65 times the diameter of the outer wall portion of the second piston component.

10. The piston component according to claim 8, wherein the second piston component includes a second piston, a seal, and a stop, the seal having an annular structure, the seal being made of plastic material, the second piston having a stepped portion, the seal and the stop being sleeved on the stepped portion, the seal abutting against the step of the stepped portion on its inner side; the first piston component includes a first piston, the first piston having a sealing mating portion provided on one side of its inner cavity, the outer side of the seal being able to cooperate with the sealing mating portion of the first piston for sealing and limiting, the seal being smaller than or equal to the outer wall portion of the second piston for sliding engagement, and the stop being smaller than the seal of the second piston component.

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