Valve needle assembly, valve body module and electronic expansion valve

Abstract

According to the valve needle assembly, the valve body module and the electronic expansion valve, the second side hole of the small valve needle is formed in the middle, so that when the small valve needle is closed, the second side hole directly communicates with the first side hole, and fluid can directly enter the pressure balance shaft hole in the small valve needle from the first side hole through the second side hole; the direction of fluid does not need to be changed in the process, so that the number of corners is reduced, a flow channel is simplified, flow resistance is reduced, and it is guaranteed that the actual maximum flow of the expansion valve is basically consistent with the flow needed by design.

Description

Technical Field

[0001] The present application relates to the field of valve technology, and in particular to a valve needle assembly, a valve body module and an electronic expansion valve. Background Art

[0002] A dual-needle electronic expansion valve regulates fluid flow through the coordinated operation of two valve needles. When a lower flow rate is required, the valve can operate with a small opening, with one or both valve needles slightly opened to precisely control flow. When a higher flow rate is required, the valve needles can be fully opened, similar to the function of a solenoid valve, while also providing bidirectional flow control.

[0003] However, in current electronic expansion valves, the fluid needs to change direction multiple times when entering the small valve needle from the large valve needle, and the flow path is complex, resulting in a large flow resistance, causing the maximum flow rate actually output by the expansion valve to be lower than the design required flow rate. Utility Model Content

[0004] The purpose of this application is to provide a valve needle assembly, a valve body module and an electronic expansion valve, which reduce the number of corners, simplify the flow channel, and thus reduce the flow resistance to ensure that the actual maximum flow of the expansion valve is basically consistent with the design required flow.

[0005] The embodiments of the present application can be implemented as follows:

[0006] In a first aspect, the utility model provides a valve needle assembly, comprising a large valve needle and a small valve needle;

[0007] The large valve needle has a valve needle shaft hole, a first side hole and a shaft outlet hole, and the first side hole and the shaft outlet hole are both connected to the valve needle shaft hole;

[0008] The small valve needle is slidably matched with the valve needle shaft hole, and the small valve needle has a pressure balance shaft hole, a second side hole and a third side hole. The second side hole and the third side hole are both connected to the pressure balance shaft hole. The second side hole is located in the middle of the small valve needle. The third side hole is closer to the shaft outlet hole than the second side hole, and the third side hole is connected to the valve needle shaft hole.

[0009] When the small valve needle and the large valve needle are both in a closed state, the small valve needle blocks the shaft outlet hole, and the second side hole is communicated with the first side hole;

[0010] When the small valve needle is in a fully open state, the small valve needle blocks the second side hole and opens the shaft outlet hole.

[0011] In an optional embodiment, a first annular groove extending circumferentially is provided on the inner wall of the valve needle shaft hole, the width of the first annular groove is larger than the diameter of the first side hole, and the first side hole passes through the bottom of the first annular groove;

[0012] When the small valve needle is in a closed state, the first annular groove is communicated with the second side hole;

[0013] When the small valve needle is in a fully open state, the small valve needle blocks the first annular groove.

[0014] In an optional embodiment, the outer peripheral wall of the small valve needle is provided with a circumferentially extending second annular groove, the groove width of the second annular groove is larger than the aperture of the second side hole, and the second side hole passes through the groove bottom of the second side hole;

[0015] When the small valve needle is in a closed state, the first side hole is communicated with the second annular groove;

[0016] When the small valve needle is in a fully open state, the inner peripheral wall of the valve needle shaft hole blocks the second annular groove.

[0017] In an optional embodiment, there are multiple first side holes, and the first side holes are circumferentially spaced around the central axis of the large valve needle;

[0018] and / or,

[0019] There are a plurality of the second side holes and the third side holes, and the second side holes and the third side holes are circumferentially spaced around the central axis of the small valve needle.

[0020] In an optional embodiment, the valve needle assembly further includes a limit retaining ring, the limit retaining ring is mounted on an end of the large valve needle facing away from the shaft outlet hole, and the small valve needle is inserted into the limit retaining ring;

[0021] When the small valve needle is in a fully open state, the small valve needle abuts against a surface of the limit ring facing the shaft outlet hole.

[0022] In an optional embodiment, a mounting groove is provided at the end of the large valve needle, the inner diameter of the mounting groove is larger than the inner diameter of the valve needle shaft hole, the valve needle shaft hole passes through the bottom of the mounting groove, and the limit ring is installed in the mounting groove;

[0023] and / or,

[0024] The limit ring is provided with a radial through hole, and the small valve needle further has a fourth side hole. The fourth side hole is located on a side of the second side hole away from the third side hole, and the fourth side hole is connected to the radial through hole.

[0025] In an optional embodiment, the small valve needle includes a connecting section, a sliding section and a blocking section connected in sequence, the outer diameter of the sliding section is larger than the outer diameter of the connecting section and the outer diameter of the blocking section, the sliding section is slidably matched with the valve needle shaft hole, the connecting section is used to connect the drive assembly, the pressure balance shaft hole extends from one end of the connecting section away from the sliding section to the blocking section, the second side hole is provided in the middle of the sliding section, and the third side hole is provided in the blocking section;

[0026] When the small valve needle is in a closed state, the blocking section blocks the shaft outlet hole;

[0027] When the small valve needle is in a fully open state, the sliding section blocks the first side hole, and the blocking section opens the shaft outlet hole.

[0028] In an optional embodiment, the small valve needle further has a fifth side hole, and the fifth side hole is located on a side of the second side hole away from the third side hole.

[0029] In the second aspect, the utility model provides a valve body module, comprising a valve body and a valve needle assembly as described in any one of the aforementioned embodiments, the valve body having an accommodating cavity and a fluid input port and a fluid output port connected to the accommodating cavity, the large valve needle slidingly cooperates with the accommodating cavity, the first side hole is connected to the fluid input port, and the shaft outlet hole is connected to the fluid output port.

[0030] In a third aspect, the present invention provides an electronic expansion valve, comprising the valve body module described in the aforementioned embodiment.

[0031] Compared with the prior art, the beneficial effects of the embodiments of the present application include, for example:

[0032] By setting the second side hole of the small valve needle in the middle, the second side hole and the first side hole are directly connected when the small valve needle is closed, so that the fluid can directly enter the pressure balance shaft hole inside the small valve needle from the first side hole through the second side hole. The fluid does not need to change direction during this process, thereby reducing the number of turns, simplifying the flow channel, and reducing the flow resistance, so as to ensure that the actual maximum flow of the expansion valve is basically consistent with the design required flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 Schematic diagram of the fluid flow direction of the valve body module in the prior art when the small valve needle is closed;

[0035] Figure 2 Schematic diagram of the fluid flow direction of the valve body module in the prior art when the small valve needle is fully open;

[0036] Figure 3 This is a three-dimensional diagram of an electronic expansion valve according to an embodiment of the present application;

[0037] Figure 4 for Figure 3 sectional view of

[0038] Figure 5 for Figure 4 A three-dimensional view of the medium and large valve needle;

[0039] Figure 6 for Figure 5 sectional view of

[0040] Figure 7 for Figure 4 Stereoscopic view of small and medium valve needles;

[0041] Figure 8 for Figure 7 sectional view of

[0042] Figure 9 This is a schematic diagram of the fluid flow direction of the valve body module when both the large valve needle and the small valve needle are closed according to an embodiment of the present application;

[0043] Figure 10 This is a schematic diagram of the fluid flow direction of the valve body module during the opening of the small valve needle in an embodiment of the present application;

[0044] Figure 11 This is a schematic diagram of the fluid flow direction of the valve body module when the small valve needle is fully open in the embodiment of the present application;

[0045] Figure 12 This is a schematic diagram of the fluid flow direction of the valve body module when the large valve needle is opened according to an embodiment of the present application.

[0046] Icons: 100-electronic expansion valve; 110-valve body; 111-fluid inlet; 112-fluid outlet; 113-accommodation chamber; 114-connecting ring; 115-stop block; 116-limit block; 117-large spring; 118-sealing gasket; 119-limiting retaining ring; 120-sleeve; 130-drive assembly; 131-motor; 132-threaded rod; 133-nut block; 140-large valve needle; 141-valve needle shaft hole; 142-first ring groove; 143-first Side hole; 144-shaft outlet hole; 145-installation groove; 150-small valve needle; 151-pressure balance shaft hole; 152-second side hole; 153-third side hole; 154-connecting section; 155-sliding section; 156-sealing section; 157-fourth side hole; 158-fifth side hole; 159-limiting part; 160-spring pad; 161-spring seat; 162-small spring; 170-first sealing ring; 171-second sealing ring; 172-radial through hole; 173-second annular groove. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0049] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0050] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended only to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0051] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0052] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0053] The structure of the valve body 110 assembly in the prior art is as follows Figures 1 to 3 As shown, after the airflow enters the large valve needle 140, it needs to first go through a corner and then enter the flow channel between the inner wall of the large valve needle 140 and the outer wall of the small valve needle 150, and then go through a corner again to enter the small valve needle 150. The fluid needs to change direction repeatedly, with many corners and complex flow channels, resulting in a large flow resistance, making the actual maximum flow rate of the electronic expansion valve 100 far lower than the design required flow rate.

[0054] To this end, the inventors have provided the following embodiments for improvement after research, so as to reduce the number of corners, simplify the flow channel, and reduce the flow resistance.

[0055] The following combination Figures 3 to 12 , some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0056] The embodiment of the present application discloses an electronic expansion valve 100 , which includes a sleeve 120 , a drive assembly 130 , and a valve body module;

[0057] The sleeve 120 is connected to the valve body module. The drive assembly 130 is disposed in the sleeve 120 and connected to the valve needle of the valve body 110 assembly to open or close the valve needle.

[0058] The valve module includes a valve body 110 and a valve needle assembly. The valve body 110 has an accommodating chamber 113 and a fluid inlet 111 and a fluid outlet 112 communicating with the accommodating chamber 113. The fluid inlet 111 passes through the side wall of the valve body 110, and the fluid outlet 112 passes through the end wall of the valve body 110. The sleeve 120 is connected to a portion of the valve body 110 away from the fluid outlet 112 to seal the opening at the other end of the valve body 110, that is, the opening of the accommodating chamber 113.

[0059] The valve needle assembly includes a large valve needle 140 and a small valve needle 150. The large valve needle 140 is slidably engaged with the accommodating cavity 113.

[0060] The large valve needle 140 has a valve needle shaft hole 141, a first side hole 143 and a shaft outlet hole 144. The first side hole 143 and the shaft outlet hole 144 are both connected to the valve needle shaft hole 141; the first side hole 143 is connected to the fluid input port 111, and the shaft outlet hole 144 is connected to the fluid output port 112.

[0061] The small valve needle 150 is in sliding engagement with the valve needle shaft hole 141. The small valve needle 150 has a pressure balance shaft hole 151, a second side hole 152, and a third side hole 153. The second side hole 152 and the third side hole 153 are both in communication with the pressure balance shaft hole 151. The third side hole 153 is closer to the shaft outlet hole 144 than the second side hole 152, and the third side hole 153 is in communication with the valve needle shaft hole 141.

[0062] When the small valve needle 150 and the large valve needle 140 are both in the closed state, the small valve needle 150 blocks the shaft outlet hole 144, and the second side hole 152 is connected to the first side hole 143;

[0063] When the small valve needle 150 is in the fully open state, the small valve needle 150 blocks the second side hole 152 and opens the shaft outlet hole 144 .

[0064] When the small valve needle 150 and the large valve needle 140 are both in the fully open state, the large valve needle 140 opens the fluid output port 112 .

[0065] In this way, by setting the second side hole 152 of the small valve needle 150 in the middle, the second side hole 152 and the first side hole 143 are directly connected when the small valve needle 150 is closed. In this way, the fluid can directly enter the pressure balance shaft hole 151 inside the small valve needle 150 from the first side hole 143 through the second side hole 152. The fluid does not need to change direction during this process, thereby reducing the number of corners, simplifying the flow channel, and reducing the flow resistance, so as to ensure that the actual maximum flow of the expansion valve is basically consistent with the design required flow.

[0066] The drive assembly 130 includes a motor 131, a threaded rod 132 and a nut block 133. The motor 131 is fixed to the sleeve 120, the threaded rod 132 is connected to the motor 131, the nut block 133 is threadedly engaged with the threaded rod 132, and the small valve needle 150 is connected to the nut block 133. In this way, the motor 131 provides torque to rotate the threaded rod 132, and then the nut block 133 spirally moves relative to the threaded rod 132 to convert the torque into a linear driving force that can drive the small valve needle 150 to perform reciprocating linear motion in the axial direction.

[0067] To achieve the connection between the valve body 110 and the sleeve 120, a connecting ring 114 is mounted on the valve body 110. The contact section between the connecting ring 114 and the valve body 110 is welded, for example, by laser welding. A stop block 115 is also provided on the end of the valve body 110 away from the fluid outlet 112. A limit block 116 is mounted on the stop block 115. A nut block 133 is slidably disposed within the limit block 116. The threaded rod 132 is rotatably mounted through the limit block 116 via a bearing. The limit block 116 can locate the axial position of the threaded rod 132 and prevent the nut block 133 from rotating. The stop block 115 can abut against the nut block 133 to limit the range of movement of the nut block 133 toward the interior of the valve body 110, preventing the nut block 133 from moving excessively. A large spring 117 is provided between the stop block 115 and the large valve needle 140. The large spring 117 is in a compressed state, thereby providing the large valve needle 140 with an elastic force to move toward the fluid outlet 112, so that the sealing gasket 118 on the large valve needle 140 can abut against the bottom of the accommodating chamber 113 to form a seal.

[0068] The valve needle assembly further includes a limit ring 119 , which is mounted on one end of the large valve needle 140 facing away from the shaft outlet 144 . The small valve needle 150 passes through the limit ring 119 so as to be connected to the drive assembly 130 .

[0069] When the small valve needle 150 is in the fully open state, the small valve needle 150 abuts against the side of the limit ring 119 facing the shaft outlet hole 144, so that the limit ring 119 can limit the axial position of the small valve needle 150 relative to the large valve needle 140, so that after the small valve needle 150 abuts against the limit ring 119, the drive assembly 130 continues to pull the small valve needle 150 to indirectly lift the large valve needle 140, thereby realizing the opening of the large valve needle 140.

[0070] The large spring 117 is sleeved outside the limiting retaining ring 119 and abuts between the stop block 115 and the limiting retaining ring 119 to push against the limiting retaining ring 119, thereby providing elastic force for the large valve needle 140 to move toward the fluid output port 112.

[0071] A mounting groove 145 is provided at the end of the large valve needle 140. The inner diameter of the mounting groove 145 is larger than the inner diameter of the valve needle shaft hole 141. The valve needle shaft hole 141 passes through the bottom of the mounting groove 145. The limit ring 119 is installed in the mounting groove 145 to realize the installation of the limit ring 119.

[0072] The limiting retaining ring 119 is provided with a radial through hole 172, and the small valve needle 150 also has a fourth side hole 157. The fourth side hole 157 is located on the side of the second side hole 152 away from the third side hole 153. The fourth side hole 157 is connected with the radial through hole 172. Specifically, the fourth side hole 157 and the radial through hole 172 are connected through the gap between the inner circumferential wall of the limiting retaining ring 119 and the outer circumferential wall of the small valve needle 150. In this way, a part of the high-pressure fluid in the pressure balance shaft hole 151 can reach the side of the limiting retaining ring 119 from the side, thereby reducing the pressure above the limiting retaining ring 119, and then indirectly reducing the pressure difference at both ends of the large valve needle 140, thereby improving the valve opening ability of the large valve needle 140 after the small valve needle 150 is fully opened.

[0073] A circumferentially extending first annular groove 142 is provided on the inner wall of the valve needle shaft hole 141. The width of the first annular groove 142 is greater than the diameter of the first side hole 143, and the first side hole 143 extends through the bottom of the first annular groove 142. When the small valve needle 150 is closed, the first annular groove 142 communicates with the second side hole 152. When the small valve needle 150 is fully open, the small valve needle 150 blocks the first annular groove 142. This further reduces flow resistance.

[0074] There is no specific limit to the number of the first side holes 143 , which may be one or more. When there are more than one first side holes 143 , the first side holes 143 are circumferentially spaced around the central axis of the large valve needle 140 .

[0075] The small valve needle 150 includes a connecting section 154, a sliding section 155 and a blocking section 156 connected in sequence. The outer diameter of the sliding section 155 is larger than the outer diameter of the connecting section 154 and the outer diameter of the blocking section 156. The sliding section 155 slides in cooperation with the valve needle shaft hole 141. The connecting section 154 is used to connect the nut block 133 of the drive assembly 130. The pressure balance shaft hole 151 extends from one end of the connecting section 154 away from the sliding section 155 to the blocking section 156. The second side hole 152 is arranged in the middle of the sliding section 155, and the third side hole 153 is arranged in the blocking section 156; when the small valve needle 150 is in the closed state, the blocking section 156 blocks the shaft outlet hole 144; when the small valve needle 150 is in the fully open state, the sliding section 155 blocks the first side hole 143, and the blocking section 156 opens the shaft outlet hole 144.

[0076] The fourth side hole 157 is provided in the connecting section 154 , and the sliding section 155 is located between the limit ring 119 and the shaft outlet hole 144 , so that the small valve needle 150 reaches a fully open state when the end surface of the sliding section 155 facing away from the shaft outlet hole 144 abuts against the limit ring 119 .

[0077] A circumferentially extending second annular groove 173 is provided on the outer circumferential wall of the sliding section 155 of the small valve needle 150. The width of the second annular groove 173 is greater than the diameter of the second side hole 152, and the second side hole 152 extends through the bottom of the second side hole 152. When the small valve needle 150 is closed, the first side hole 143 communicates with the second annular groove 173 through the second annular groove 173. When the small valve needle 150 is fully open, the inner circumferential wall of the valve needle shaft hole 141 blocks the second annular groove 173, thereby blocking the communication between the second annular groove 173 and the first annular groove 142. This further reduces flow resistance.

[0078] The connecting section 154 of the small valve needle 150 also has a fifth side hole 158. The fifth side hole 158 is located on the side of the second side hole 152 away from the third side hole 153, and is also located on the side of the fourth side hole 157 away from the second side hole 152. The fifth side hole 158 is axially offset from the limit retaining ring 119. In this way, by providing the fifth side hole 158, part of the high-pressure fluid can be further allowed to enter the side of the limit retaining ring 119 and the small valve needle 150 from the side, thereby reducing the pressure of the upper high-pressure gas to the large valve needle 140 as a whole, and further improving the valve opening ability of the large valve needle 140 after the small valve needle 150 is fully opened.

[0079] The number of the second side hole 152, the third side hole 153, the fourth side hole 157 and the fifth side hole 158 is not specifically limited in the present application; for example, the number of the second side hole 152, the third side hole 153, the fourth side hole 157 and the fifth side hole 158 are all multiple, and each second side hole 152, each third side hole 153, each fourth side hole 157 and each fifth side hole 158 are distributed in a circular pattern around the central axis of the small valve needle 150.

[0080] Among them, a radially outward extending limiting portion 159 is formed at the position of the connecting section 154 away from the sliding section 155, so that the nut block 133 can be embedded in the limiting portion 159. At the same time, a spring pad 160 and a spring seat 161 arranged on the spring pad 160 and a small spring 162 sleeved outside the spring seat 161 are installed in the pressure balance shaft hole 151 of the small valve needle 150. The small spring 162 abuts between the spring pad 160 and the nut block 133, so that the elastic force of the small spring 162 makes the limiting portion 159 abut against the nut block 133, thereby realizing the connection between the small valve needle 150 and the nut block 133.

[0081] In addition, a first sealing ring 170 is provided outside the connecting ring 114, and a second sealing ring 171 is provided outside the valve body 110, so as to be embedded with the high-pressure container to achieve a seal between the valve body 110 and the high-pressure container, thereby ensuring that high-pressure gas does not overflow from the gap between the valve body 110 and the high-pressure container.

[0082] The working principle of the electronic expansion valve 100 in the embodiment of the present application is as follows:

[0083] like Figure 7 It is the flow channel and direction in the valve closing state. In the valve closing state, the sealing section 156 of the small valve needle 150 blocks the shaft outlet hole 144. At this time, the fluid flow direction is the air inlet chamber A-the air inlet of the large valve needle 140-the air inlet channel of the large valve needle 140-the internal channel of the small valve needle 150-the internal chamber B of the valve and the chamber between the small valve needle 150 and the large valve needle 140. Compared with the flow channel of the small valve needle 150 section before the improvement, the length of the flow channel is significantly shortened, the number of bends is reduced, and the complexity of the flow channel is reduced, so that the maximum flow rate of the small valve needle 150 section can be improved. At the same time, the outlet seal of the large valve needle 140 is blocked, and the entire valve interior is filled with high intake pressure. The resulting force is downward, and the magnitude of the force is the product of the intake pressure and the cross-sectional area of ​​the outlet of the large valve needle 140. Since the cross-sectional area of ​​the outlet of the small valve needle 150 is very small, although the intake pressure is high at this time, the force applied to the small valve needle 150 is very small. At this time, the motor 131 only needs to overcome a very small force to easily open the small valve needle 150.

[0084] After the large valve needle 140, small valve needle 150, and limit ring 119 are assembled, in the valve closed state (i.e., both the large valve needle 140 and the small valve needle 150 are closed), the airtight end of the small valve needle 150 contacts the bottom of the valve needle shaft hole 141 of the large valve needle 140 to form a seal, thereby blocking the shaft outlet hole 144. At this time, the fluid flow direction is fluid input port 111 → first side hole 143 → first annular groove 142 → second annular groove 173 → second side hole 152 → pressure balance shaft hole 151 → chamber B and third side hole 153. Compared with the fluid flow route of the prior art, the present application significantly shortens the length of the flow channel, reduces the number of bends, and reduces the complexity of the flow channel, thereby increasing the maximum flow rate of the small valve needle 150 section. At the same time, the shaft outlet hole 144 of the large valve needle 140 is blocked and sealed by the sealing section 156 of the small valve needle 150, and the resultant force of the high air pressure on the small valve needle 150 is downward (that is, the resultant force of the pressure difference between the chamber between the third side hole 153 and the valve needle shaft hole 141 and the chamber B on the small valve needle 150). The magnitude of the force is the product of the intake pressure and the cross-sectional area of ​​the third side hole 153 of the small valve needle 150. Since the cross-sectional area of ​​the third side hole 153 of the small valve needle 150 is very small, although the intake pressure is high at this time, the force on the small valve needle 150 is very small. At this time, the motor 131 only needs to overcome a very small force to easily open the small valve needle 150.

[0085] After the small valve needle 150 is opened, Figure 12 As shown, the sealing section 156 of the small valve needle 150 opens the shaft outlet hole 144, and the high-pressure gas can be discharged to the chamber C through the shaft outlet hole 144. At this time, the pressure of the chamber B inside the valve begins to drop. At this time, the force acting on the small valve needle 150 is smaller, and the small valve needle 150 can rise more easily.

[0086] As the sliding section 155 of the small valve needle 150 gradually approaches the stop ring 119, the connecting area between the first annular groove 142 and the second annular groove 173 gradually decreases. When the upper end surface of the sliding section 155 of the small valve needle 150 fully contacts the bottom surface of the stop ring 119, the small valve needle 150 is fully opened. At this time, the first annular groove 142 is completely blocked by the sliding section 155, and the high-pressure fluid cannot flow into the second annular groove 173. Since the pressure in chamber B is higher than that in chamber C, the low-pressure side of chamber C is connected. The fluid flows in the direction of chamber B → pressure balance shaft hole 151 → third side hole 153 → shaft outlet hole 144 → chamber C. At this time, the pressure difference between chamber B and outlet chamber C is very small, allowing the large valve needle 140 to be easily opened with less force from the motor 131, thereby improving the valve opening capability of the large valve needle 140.

[0087] When the small valve needle 150 continues to rise, the large valve needle 140 separates from the valve body 110, the large valve needle 140 opens, and the high-pressure fluid entering the fluid input port 111 directly flows from the fluid output port 112 to the chamber C through the gap between the accommodating cavity 113 and the large valve needle 140.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A valve needle assembly, characterized in that: It includes a large valve needle (140) and a small valve needle (150); The large valve needle (140) has a valve needle shaft hole (141), a first side hole (143) and a shaft outlet hole (144), and the first side hole (143) and the shaft outlet hole (144) are both in communication with the valve needle shaft hole (141); The small valve needle (150) is slidably matched with the valve needle shaft hole (141), and the small valve needle (150) has a pressure balance shaft hole (151), a second side hole (152) and a third side hole (153). The second side hole (152) and the third side hole (153) are both connected to the pressure balance shaft hole (151). The second side hole (152) is located in the middle of the small valve needle (150). The third side hole (153) is closer to the shaft outlet hole (144) than the second side hole (152). The third side hole (153) is connected to the valve needle shaft hole (141); When the small valve needle (150) and the large valve needle (140) are both in a closed state, the small valve needle (150) blocks the shaft outlet hole (144), and the second side hole (152) is in communication with the first side hole (143); When the small valve needle (150) is in a fully open state, the small valve needle (150) blocks the second side hole (152) and opens the shaft outlet hole (144).

2. The valve needle assembly according to claim 1, characterized in that A first annular groove (142) extending circumferentially is provided on the inner wall of the valve needle shaft hole (141); the width of the first annular groove (142) is greater than the diameter of the first side hole (143); and the first side hole (143) passes through the bottom of the first annular groove (142); When the small valve needle (150) is in a closed state, the first annular groove (142) is in communication with the second side hole (152); When the small valve needle (150) is in a fully open state, the small valve needle (150) blocks the first annular groove (142).

3. The valve needle assembly according to claim 1, characterized in that The outer peripheral wall of the small valve needle (150) is provided with a circumferentially extending second annular groove (173), the groove width of the second annular groove (173) is larger than the aperture of the second side hole (152), and the second side hole (152) passes through the groove bottom of the second side hole (152); When the small valve needle (150) is in a closed state, the first side hole (143) is in communication with the second annular groove (173); When the small valve needle (150) is in a fully open state, the inner peripheral wall of the valve needle shaft hole (141) blocks the second annular groove (173).

4. The valve needle assembly according to claim 1, characterized in that There are a plurality of first side holes (143), and each of the first side holes (143) is distributed at intervals around the central axis of the large valve needle (140). and / or, There are multiple second side holes (152) and multiple third side holes (153), and each of the second side holes (152) and each of the third side holes (153) are distributed at intervals around the central axis of the small valve needle (150).

5. The valve needle assembly according to claim 1, characterized in that The valve needle assembly further comprises a limit retaining ring (119), the limit retaining ring (119) being mounted on an end of the large valve needle (140) facing away from the shaft outlet hole (144), and the small valve needle (150) being passed through the limit retaining ring (119); When the small valve needle (150) is in a fully open state, the small valve needle (150) abuts against a side of the limit ring (119) facing the shaft outlet hole (144).

6. The valve needle assembly according to claim 5, characterized in that The end of the large valve needle (140) is provided with a mounting groove (145), the inner diameter of the mounting groove (145) is larger than the inner diameter of the valve needle shaft hole (141), the valve needle shaft hole (141) passes through the bottom of the mounting groove (145), and the limit ring (119) is installed in the mounting groove (145); and / or, The limit ring (119) is provided with a radial through hole (172), and the small valve needle (150) also has a fourth side hole (157). The fourth side hole (157) is located on the side of the second side hole (152) away from the third side hole (153), and the fourth side hole (157) is connected to the radial through hole (172).

7. The valve needle assembly according to claim 1, characterized in that The small valve needle (150) includes a connecting section (154), a sliding section (155) and a blocking section (156) connected in sequence. The outer diameter of the sliding section (155) is larger than the outer diameter of the connecting section (154) and the outer diameter of the blocking section (156). The sliding section (155) is slidably matched with the valve needle shaft hole (141). The connecting section (154) is used to connect the drive assembly (130). The pressure balance shaft hole (151) extends from one end of the connecting section (154) away from the sliding section (155) to the inside of the blocking section (156). The second side hole (152) is provided in the middle of the sliding section (155). The third side hole (153) is provided in the blocking section (156). When the small valve needle (150) is in a closed state, the blocking section (156) blocks the shaft outlet hole (144); When the small valve needle (150) is in a fully open state, the sliding section (155) blocks the first side hole (143), and the blocking section (156) opens the shaft outlet hole (144).

8. The valve needle assembly according to claim 1 or 7, characterized in that: The small valve needle (150) further has a fifth side hole (158), and the fifth side hole (158) is located on a side of the second side hole (152) away from the third side hole (153).

9. A valve body module, characterized in that: It comprises a valve body (110) and a valve needle assembly according to any one of claims 1 to 8, wherein the valve body (110) has an accommodating chamber (113) and a fluid input port (111) and a fluid output port (112) connected to the accommodating chamber (113), the large valve needle (140) is slidably fitted with the accommodating chamber (113), the first side hole (143) is connected to the fluid input port (111), and the shaft outlet hole (144) is connected to the fluid output port (112).

10. An electronic expansion valve, characterized in that: Comprising the valve body module according to claim 9.

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