Valve body assembly and electronic expansion valve

Abstract

According to the valve body assembly and the electronic expansion valve, the overflowing channel located on the peripheral side of the axial mounting hole is formed in the large valve needle so that the first side inlet can communicate with the first side outlet, in this way, part of the axial mounting hole can be prevented from being expanded, and the inner diameter size of the axial mounting hole in the axial direction of the axial mounting hole can be kept constant; after the small valve needle is installed in the axial installation hole, under the condition that the small valve needle moves to be fully open relative to the large valve needle and the large valve needle is still in a closed state, good air tightness still exists between the outer circumferential wall of the small valve needle and the inner circumferential wall of the axial installation hole. Therefore, high-pressure fluid such as high-pressure gas and high-pressure liquid cannot pass through the space between the outer peripheral wall of the small valve needle and the inner peripheral wall of the axial mounting hole to reach the second side outlet due to the fact that the first side outlet is blocked by the small valve needle, the pressure difference between the two ends of the large valve needle can be reduced, and the problem that the large valve needle is difficult to open after the small valve needle is fully opened is solved.

Description

Technical Field

[0001] The present application relates to the field of valve technology, and in particular to a valve body assembly 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, with current electronic expansion valves, when the large valve needle needs to be opened after the small valve needle is fully opened, the inlet pressure is different under different working conditions. At higher inlet pressures, the inlet and outlet pressure differential is large, making it extremely difficult or even impossible to open the large valve needle. Utility Model Content

[0004] The purpose of the present application is to provide a valve body assembly and an electronic expansion valve, which can reduce the pressure difference at both ends of the large valve needle to improve the problem that the large valve needle is difficult to open after the small valve needle is fully opened.

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

[0006] In a first aspect, the present invention provides a valve body assembly, comprising:

[0007] A valve body having an accommodating cavity and a fluid input port and a fluid output port communicated with the accommodating cavity;

[0008] a large valve needle slidably disposed in the accommodating chamber, the large valve needle having an axial mounting hole, a flow passage, a first side inlet, a first side outlet, and an axial outlet, the first side inlet being in communication with the fluid input port, the first side inlet being in communication with the first side outlet via the flow passage, the flow passage being located on an outer peripheral side of the axial mounting hole, the first side outlet and the axial outlet both being in communication with the axial mounting hole;

[0009] A small valve needle is in sliding sealing cooperation with the axial mounting hole, the small valve needle has an axial balancing hole and a second side inlet and a second side outlet communicated with the axial balancing hole, the second side outlet is communicated with the axial mounting hole, and the axial balancing hole is communicated with the accommodating cavity;

[0010] When the small valve needle and the large valve needle are both in a closed state, the large valve needle blocks the fluid output port, the first side outlet is connected to the second side outlet, and the small valve needle blocks the axial outlet;

[0011] When the small valve needle is in a fully open state and the large valve needle is in a closed state, the small valve needle opens the axial outlet and blocks the first side outlet.

[0012] In an optional embodiment, the flow passage is columnar, and a plurality of the flow passages are circumferentially spaced and distributed around the outer circumference of the axial mounting hole.

[0013] In an optional embodiment, the valve body assembly further includes a limit retaining ring, which is mounted on the end of the large valve needle to cover the flow channel, and the small valve needle is inserted into the limit retaining ring;

[0014] When the small valve needle is in a fully open state, the small valve needle abuts against the limit ring in a direction away from the axial outlet.

[0015] In an optional embodiment, a mounting groove is provided at the end of the large valve needle, the flow passage and the axial mounting hole both pass through the bottom of the mounting groove, and the limit ring is installed in the mounting groove.

[0016] In an optional embodiment, the first side outlet passes through the end of the large valve needle, and the limiting retaining ring covers the first side outlet.

[0017] In an optional embodiment, the small valve needle further has a side port, which is connected to both the axial balancing hole and the accommodating cavity, and is located on a side of the second side inlet away from the second side outlet.

[0018] 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 blocking section and the outer diameter of the connecting section are both larger than the outer diameter of the sliding section, the sliding section is in sliding and sealing cooperation with the axial mounting hole, the axial balancing hole extends from one end of the connecting section away from the blocking section to the inside of the blocking section, the second side inlet is provided in the connecting section, and the second side outlet is provided in the blocking section;

[0019] When the small valve needle and the large valve needle are both in a closed state, the blocking section blocks the axial outlet;

[0020] When the small valve needle is in a fully open state and the large valve needle is in a closed state, the blocking section opens the axial outlet, and the sliding section blocks the first side outlet.

[0021] In an optional embodiment, a limiting portion extending radially outward is formed at a portion of the connecting section away from the sliding section.

[0022] In a second aspect, the present invention provides an electronic expansion valve, comprising a sleeve, a drive assembly, and a valve body assembly according to any one of the aforementioned embodiments;

[0023] The sleeve is sleeved with the valve body, the drive assembly is arranged in the sleeve, and the drive assembly is connected to a portion of the small valve needle away from the axial outlet for driving the small valve needle to move.

[0024] In an optional embodiment, the drive assembly includes a motor, a threaded rod and a nut block, the motor is fixed to the sleeve, the threaded rod is connected to the motor, the nut block is threadedly engaged with the threaded rod, and the small valve needle is connected to the nut block.

[0025] Compared with the prior art, the beneficial effects of the embodiments of the present application include, for example:

[0026] By arranging a flow passage on the outer peripheral side of the axial mounting hole on the large valve needle to connect the first side inlet and the first side outlet, it is possible to avoid enlarging part of the axial mounting hole, so that the inner diameter size of the axial mounting hole in its own axial direction remains constant. In this way, after the small valve needle is installed in the axial mounting hole, the contact area between the small valve needle and the axial mounting hole corresponding to the first side outlet to the second side outlet can be increased. In this way, when the small valve needle moves fully open relative to the large valve needle and the large valve needle is still in a closed state, there is still good air tightness between the outer peripheral wall of the small valve needle and the inner peripheral wall of the axial mounting hole. In this way, high-pressure fluids such as high-pressure gas and high-pressure liquid will not pass through the outer peripheral wall of the small valve needle and the inner peripheral wall of the axial mounting hole to reach the second side outlet because the first side outlet is blocked by the small valve needle, thereby reducing the pressure difference at both ends of the large valve needle to improve the problem that the large valve needle is difficult to open after the small valve needle is fully opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 A schematic diagram of the flow path of the valve body assembly in the prior art when both the large valve needle and the small valve needle are closed;

[0029] Figure 2 Schematic diagram of the flow path of the valve body assembly in the prior art when the small valve needle is fully open;

[0030] Figure 3 for Figure 2 Magnified view of part I;

[0031] Figure 4 This is a schematic diagram of an electronic expansion valve according to an embodiment of the present application;

[0032] Figure 5 for Figure 4 Schematic diagram of the internal structure;

[0033] Figure 6 for Figure 5 Schematic diagram of the medium and large valve needle;

[0034] Figure 7 for Figure 6 sectional view of

[0035] Figure 8 for Figure 6 A top view of

[0036] Figure 9 for Figure 5 Schematic diagram of small and medium valve needles;

[0037] Figure 10 for Figure 9 sectional view of

[0038] Figure 11 for Figure 4 Schematic diagram of the flow path of the middle valve body assembly when both the large valve needle and the small valve needle are closed;

[0039] Figure 12 for Figure 4 Schematic diagram of the flow path of the middle valve body assembly when the small valve needle is fully open;

[0040] Figure 13 for Figure 4 Schematic diagram of the flow path of the middle valve body assembly when the large valve needle is open.

[0041] 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-axial mounting hole; 142-flow channel; 1 43-first side inlet; 144-first side outlet; 145-axial outlet; 146-mounting groove; 150-small valve needle; 151-axial balancing hole; 152-second side inlet; 153-second side outlet; 154-connecting section; 155-sliding section; 156-sealing section; 157-side port; 158-limiting portion; 160-spring pad; 161-spring seat; 162-small spring; 170-first sealing ring; 171-second sealing ring; 180-inclined surface. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The structure of the valve body 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 enter the small valve needle 150 through the flow channel 142 between the inner wall of the large valve needle 140 and the inner wall of the small valve needle 150. Therefore, a part of the axial mounting hole 141 of the large valve needle 140 needs to be enlarged, so that the axial mounting hole 141 constitutes a stepped hole, so that the inner peripheral wall of the enlarged part of the axial mounting hole 141 can form the flow channel 142 with the outer peripheral wall of the small valve needle 150. The axial contact area between the outlet of the large valve needle 140 and the outlet of the small valve needle 150 is small, and the air tightness is poor. In addition, the small valve needle 150 has a bevel 180. In this way, after the small valve needle 150 is fully opened, although the inlet of the large valve needle 140 directly ventilates the small valve needle 150 is blocked by the small valve needle 150, The sealing is blocked, but the sealing is achieved only by the contact between the inclined surface 180 on the small valve needle 150 and the inner wall of the large valve needle 140, and the airtightness requirement cannot be met at all. In this way, the high-pressure gas entering the flow channel 142 will directly enter the outlet of the small valve needle 150 from the contact area between the large valve needle 140 and the small valve needle 150. Although a part of the high-pressure gas will be directly discharged from the axial outlet 145 of the large valve needle 140 to the chamber C, the other part of the high-pressure gas will enter the internal channel of the small valve needle 150 and reach the chamber B at the upper end of the large valve needle 140. This will increase the pressure in the chamber B at the upper end of the large valve needle 140, and then cause the pressure difference at both ends of the large valve needle 140 (that is, the pressure difference between chamber B and chamber C) to increase, making the large valve needle 140 extremely difficult to open or even impossible to open.

[0049] To this end, the inventors have provided a valve body assembly and an electronic expansion valve 100 having the valve body assembly after research, which can reduce the pressure difference between the inlet and outlet sides of the large valve needle 140 after the small valve needle 150 is fully opened, making the large valve needle 140 easier to open, thereby improving the valve opening ability of the large valve needle 140.

[0050] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0051] refer to Figure 4 and Figure 5 , the embodiment of the present application discloses an electronic expansion valve 100, the electronic expansion valve 100 includes a sleeve 120, a drive assembly 130 and a valve body assembly;

[0052] The sleeve 120 is connected to the valve body assembly. The drive assembly 130 is disposed in the sleeve 120 and connected to the valve needle of the valve body assembly to open or close the valve needle.

[0053] The valve body assembly includes a valve body 110, a large valve needle 140, and a small valve needle 150. 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.

[0054] Combine Figures 6 to 8 The large valve needle 140 is slidably disposed in the accommodating chamber 113. The large valve needle 140 has an axial mounting hole 141, a flow passage 142, a first side inlet 143, a first side outlet 144, and an axial outlet 145. The first side inlet 143 is in communication with the fluid input port 111. The first side inlet 143 is in communication with the first side outlet 144 through the flow passage 142. The flow passage 142 is located on the outer peripheral side of the axial mounting hole 141. The first side outlet 144 and the axial outlet 145 are both in communication with the axial mounting hole 141.

[0055] Combine Figure 9 and Figure 10 The small valve needle 150 is in sliding sealing cooperation with the axial mounting hole 141. The driving assembly 130 is connected to the portion of the small valve needle 150 away from the axial outlet 145, thereby driving the small valve needle 150 to move, so as to continue to drive the large valve needle 140 to move after the small valve needle 150 is fully opened, thereby opening the large valve needle 140. The small valve needle 150 has an axial balancing hole 151 and a second side inlet 152 and a second side outlet 153 communicated with the axial balancing hole 151. The second side outlet 153 is communicated with the axial mounting hole 141, and the axial balancing hole 151 is communicated with the accommodating chamber 113.

[0056] Combine Figure 11 When the small valve needle 150 and the large valve needle 140 are both in the closed state, the large valve needle 140 blocks the fluid output port 112 , the first side outlet 144 is connected to the second side outlet 153 , and the small valve needle 150 blocks the axial outlet 145 ;

[0057] Combine Figure 12 When the small valve needle 150 is in the fully open state and the large valve needle 140 is in the closed state, the small valve needle 150 opens the axial outlet 145 and blocks the first side outlet 144;

[0058] Combine Figure 13 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 .

[0059] In this way, by providing a flow passage 142 on the outer peripheral side of the axial mounting hole 141 on the large valve needle 140 to connect the first side inlet 143 and the first side outlet 144, it is possible to avoid expanding part of the axial mounting hole 141, so that the inner diameter of the axial mounting hole 141 in its own axial direction remains constant. After the small valve needle 150 is installed in the axial mounting hole 141, the contact area between the small valve needle 150 and the axial mounting hole 141 corresponding to the first side outlet 144 to the second side outlet 153 can be increased, so that when the small valve needle 150 is installed in the axial mounting hole 141, the contact area between the small valve needle 150 and the axial mounting hole 141 corresponding to the first side outlet 144 and the second side outlet 153 can be increased. When the large valve needle 140 moves to fully open but the large valve needle 140 is still in a closed state, there is still good air tightness between the outer circumferential wall of the small valve needle 150 and the inner circumferential wall of the axial mounting hole 141. In this way, high-pressure fluids such as high-pressure gas and high-pressure liquid will not pass through the outer circumferential wall of the small valve needle 150 and the inner circumferential wall of the axial mounting hole 141 to reach the second side outlet 153 because the first side outlet 144 is blocked by the small valve needle 150, thereby reducing the pressure difference at both ends of the large valve needle 140 to improve the problem that the large valve needle 140 is difficult to open after the small valve needle 150 is fully opened.

[0060] In addition, since the pressure difference between the two ends of the large valve needle 140 is large after the small valve needle 150 is fully opened in the prior art, the prior art usually adopts the method of increasing the power of the drive component 130 to solve the problem that the large valve needle 140 cannot be opened. The drive component 130 usually adopts the motor 131 as the driving source, so the torque of the motor 131 is usually increased, which usually requires a motor 131 with greater torque and a greater driving current. However, when using the embodiment of the present application, it is only necessary to change the corresponding structure of the large valve needle 140, which can save more costs.

[0061] For details, please refer to Figure 4 and Figure 5 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, thereby converting the torque into a linear driving force that can drive the small valve needle 150 to perform reciprocating linear motion in the axial direction.

[0062] 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.

[0063] The valve body assembly also includes a limit ring 119, which is installed at the end of the large valve needle 140, specifically at the end of the large valve needle 140 away from the axial outlet 145. In this way, the limit ring 119 is used to cover the gap in the flow channel 142 processed by the large valve needle 140, that is, to cover the flow channel 142, thereby sealing the flow channel 142. The small valve needle 150 is passed through the limit ring 119 so that it can be connected to the drive assembly 130.

[0064] When the small valve needle 150 is in the fully open state, the small valve needle 150 abuts against the limit ring 119 in the direction away from the axial outlet 145, so that the drive assembly 130 continues to pull the small valve needle 150 to move by itself to lift the large valve needle 140, thereby realizing the opening of the large valve needle 140.

[0065] 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.

[0066] Among them, continue to combine Figure 7 and Figure 8 The flow channel 142 can be annular and surround the outer peripheral side of the axial mounting hole 141. In addition, the flow channel 142 can also be cylindrical, and each first side inlet 143 and the first side outlet 144 can be connected through the flow channel 142. For example, multiple cylindrical flow channels 142 are distributed at circumferential intervals around the outer peripheral side of the axial mounting hole 141.

[0067] In order to facilitate the installation of the limit ring 119, a mounting groove 146 is provided on the end of the large valve needle 140 away from the axial outlet 145. The flow channel 142 and the axial mounting hole 141 both pass through the bottom of the mounting groove 146, and the limit ring 119 is installed in the mounting groove 146.

[0068] The first side outlet 144 passes through the end of the large valve needle 140, and the limit ring 119 covers the first side outlet 144, so that the axial distance between the first side outlet 144 and the first side outlet 144 is large enough to better ensure the air tightness of the contact area between the large valve needle 140 and the small valve needle 150 after the small valve needle 150 is fully opened.

[0069] Continue to combine Figure 9 and Figure 10 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 blocking section 156 and the outer diameter of the connecting section 154 are both larger than the outer diameter of the sliding section 155. The sliding section 155 slides and seals with the axial mounting hole 141. The axial balance hole 151 extends from the end of the connecting section 154 away from the blocking section 156 to the blocking section 156. The second side inlet 152 is provided in the connecting section 154, and the second side outlet 153 is provided in the blocking section 156; the connecting section 154 is connected to the nut block 133 of the drive assembly 130. When the small valve needle 150 and the large valve needle 140 are both in the closed state, the blocking section 156 blocks the axial outlet 145; when the small valve needle 150 is in the fully open state and the large valve needle 140 is in the closed state, the blocking section 156 opens the axial outlet 145, and the sliding section 155 blocks the first side outlet 144.

[0070] The small valve needle 150 also has a side port 157, which is specifically opened in the connecting section 154. The side port 157 is connected to the axial balancing hole 151 and the accommodating chamber 113, and the side port 157 is located on the side of the second side inlet 152 away from the second side outlet 153. In this way, by providing the side port 157, part of the high-pressure gas can enter the side of the large valve needle 140 and the small valve needle 150 from the side, thereby reducing the pressure of the upper ends of the large valve needle 140 and the small valve needle 150 (that is, the end close to the nut block 133), 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.

[0071] Among them, a radially outward extending limiting portion 158 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 158. 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 axial balance 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 158 abut against the nut block 133, thereby realizing the connection between the small valve needle 150 and the nut block 133.

[0072] 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.

[0073] The working principle of the electronic expansion valve 100 in the embodiment of the present application is as follows:

[0074] After the large valve needle 140, the small valve needle 150 and the limit ring 119 are assembled, in the valve closing state (that is, the large valve needle 140 and the small valve needle 150 are closed), as shown in FIG. Figure 11 As shown, the bottom of the small valve needle 150 contacts the bottom of the axial mounting hole 141 of the large valve needle 140 to form a seal to block the axial outlet 145. At this time, the fluid flow direction is fluid input port 111 → first air inlet → flow channel 142 → second side inlet 152 → axial balance hole 151 → chamber B and second side outlet 153. At this time, the axial outlet 145 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 second side outlet 153 and the axial mounting 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 second side outlet 153 of the small valve needle 150. Since the cross-sectional area of ​​the second side outlet 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.

[0075] After the small valve needle 150 is opened, Figure 12 As shown, the sealing section 156 of the small valve needle 150 opens the axial outlet 145, and the high-pressure gas can be discharged to the chamber C through the axial outlet 145. 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.

[0076] When the upper end surface of the sliding section 155 of the small valve needle 150 is in full contact with the bottom surface of the limit ring 119, Figure 12As shown, the small valve needle 150 is fully open. At this time, the first side outlet 144 is blocked by the sliding section 155 of the small valve needle 150, and chamber B and chamber C are connected. Since the side of chamber C is the low-pressure side, the flow direction of the fluid is chamber B → axial balancing hole 151 → second side outlet 153 → axial outlet 145 → chamber C. Therefore, the main factor affecting the opening of the large valve needle 140 at this time is the pressure difference between chamber B and chamber C. The design before the improvement has poor air tightness due to the short contact section and the inclined surface 180 design between the large valve needle 140 and the small valve needle 150, resulting in a large pressure difference between chamber B and chamber C, and poor valve opening ability of the large valve needle 140. Therefore, the present application improves air tightness by increasing the contact section length between the inner wall surface of the large valve needle 140 and the small valve needle 150, reducing the pressure difference between chamber B and chamber C, and improving the valve opening ability of the large valve needle 140.

[0077] When the large valve needle 140 is lifted, Figure 13 As shown, the high-pressure gas entering the fluid input port 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 .

[0078] 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 body assembly, characterized in that: include: A valve body (110) having an accommodating cavity (113) and a fluid input port (111) and a fluid output port (112) communicating with the accommodating cavity (113); A large valve needle (140) is slidably disposed in the accommodating chamber (113), and the large valve needle (140) has an axial mounting hole (141), a flow passage (142), a first side inlet (143), a first side outlet (144), and an axial outlet (145). The first side inlet (143) is in communication with the fluid input port (111), and the first side inlet (143) is in communication with the first side outlet (144) through the flow passage (142). The flow passage (142) is located on the outer peripheral side of the axial mounting hole (141), and the first side outlet (144) and the axial outlet (145) are both in communication with the axial mounting hole (141). A small valve needle (150) is in sliding sealing cooperation with the axial mounting hole (141), the small valve needle (150) having an axial balancing hole (151) and a second side inlet (152) and a second side outlet (153) communicating with the axial balancing hole (151), the second side outlet (153) communicating with the axial mounting hole (141), and the axial balancing hole (151) communicating with the accommodating cavity (113); When the small valve needle (150) and the large valve needle (140) are both in a closed state, the large valve needle (140) blocks the fluid output port (112), the first side outlet (144) is connected to the second side outlet (153), and the small valve needle (150) blocks the axial outlet (145); When the small valve needle (150) is in a fully open state and the large valve needle (140) is in a closed state, the small valve needle (150) opens the axial outlet (145) and blocks the first side outlet (144).

2. The valve body assembly according to claim 1, wherein: The flow passage (142) is columnar, and a plurality of the flow passages (142) are circumferentially spaced and distributed around the outer circumference of the axial mounting hole (141).

3. The valve body assembly according to claim 1 or 2, characterized in that: The valve body assembly further comprises a limit ring (119), wherein the limit ring (119) is mounted on the end of the large valve needle (140) to cover the flow passage (142), and the small valve needle (150) is passed through the limit ring (119); When the small valve needle (150) is in a fully open state, the small valve needle (150) abuts against the limit ring (119) in a direction away from the axial outlet (145).

4. The valve body assembly according to claim 3, wherein: The end of the large valve needle (140) is provided with a mounting groove (146), the flow passage (142) and the axial mounting hole (141) both pass through the bottom of the mounting groove (146), and the limit ring (119) is installed in the mounting groove (146).

5. The valve body assembly according to claim 3, wherein: The first side outlet (144) passes through the end of the large valve needle (140), and the limiting retaining ring (119) covers the first side outlet (144).

6. The valve body assembly according to claim 1, wherein: The small valve needle (150) further has a side port (157), which is connected to both the axial balancing hole (151) and the accommodating chamber (113), and is located on a side of the second side inlet (152) away from the second side outlet (153).

7. The valve body assembly according to claim 1 or 6, 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 blocking section (156) and the outer diameter of the connecting section (154) are both larger than the outer diameter of the sliding section (155). The sliding section (155) and the axial mounting hole (141) are slidingly sealed. The axial balancing hole (151) extends from one end of the connecting section (154) away from the blocking section (156) to the inside of the blocking section (156). The second side inlet (152) is provided in the connecting section (154), and the second side outlet (153) is provided in the blocking section (156). When the small valve needle (150) and the large valve needle (140) are both in a closed state, the blocking section (156) blocks the axial outlet (145); When the small valve needle (150) is in a fully open state and the large valve needle (140) is in a closed state, the blocking section (156) opens the axial outlet (145) and the sliding section (155) blocks the first side outlet (144).

8. The valve body assembly according to claim 7, wherein: A limiting portion (158) extending radially outward is formed at a portion of the connecting section (154) away from the sliding section (155).

9. An electronic expansion valve, characterized in that: It comprises a sleeve (120), a drive assembly (130) and a valve body assembly according to any one of claims 1 to 7; The sleeve (120) is sleeved with the valve body (110), the drive assembly (130) is arranged in the sleeve (120), and the drive assembly (130) is connected to a portion of the small valve needle (150) away from the axial outlet (145) for driving the small valve needle (150) to move.

10. The electronic expansion valve according to claim 9, characterized in that: The driving assembly (130) includes a motor (131), a threaded rod (132) and a nut block (133), wherein 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).

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