Valve needle assembly and double-valve-needle electronic expansion valve

Abstract

The utility model provides a valve needle assembly and a double-valve-needle electronic expansion valve, and relates to the field of electric valves. The valve needle assembly comprises a large valve needle and a small valve needle. The large valve needle comprises a valve head and a valve cylinder which are formed in a split mode. The valve head is provided with a first end and a second end which are opposite, a blind hole is formed in the center of the first end, a through hole is formed in the outer periphery of the blind hole, a side hole communicated with the blind hole is formed in the side wall of the valve head, and a sealing conical surface is arranged at an opening of the blind hole. The valve cylinder is cylindrical and is provided with a mounting cavity. One side of the valve head at the first end is connected with the valve cylinder. The small valve needle is movably mounted in the mounting cavity, the sealing end corresponds to the sealing conical surface, and the connecting end extends out of the end part of the valve cylinder. A limiting ring table is arranged on the side wall of the mounting cavity, an abutting table matched with the limiting ring table is arranged on the side wall of the small valve needle, and after the small valve needle moves relative to the valve cylinder, the abutting table can abut against the limiting ring table to drive the large valve needle to move. The processing difficulty of the valve needle assembly can be reduced, the qualified rate of products is improved, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electric control valve, specifically, relate to a valve needle subassembly and double valve needle electronic expansion valve. BACKGROUND

[0002] In the field of refrigeration systems, double valve needle electronic expansion valve can realize high-precision dynamic regulation and control of refrigerant flow in the range of 0-100% opening degree due to its unique double valve core linkage structure, and is especially suitable for variable frequency air conditioners and other application scenarios with strict energy efficiency ratio requirements. The double valve needle electronic expansion drives the valve needle group linear displacement through a stepping motor, and realizes accurate control of the throttling section through the coordinated movement of the double valve needle, and the dynamic response speed can reach milliseconds, which is 5-8 times higher than that of the traditional thermal expansion valve.

[0003] However, when the valve needle of the double valve needle electronic expansion valve is in a closed state, the high pressure difference (usually up to 3-5 MPa) at both ends of the valve needle will generate a mechanical resistance of up to 15-20 N, resulting in an increase of more than 40% in the motor starting torque requirement compared with the normal pressure working condition, thereby affecting the response efficiency of the valve needle when it is opened. To solve this problem, the conventional design adopts a balance hole structure to compensate for the pressure, but this solution will significantly increase the processing difficulty of the valve needle assembly in the double valve needle electronic expansion valve, affecting the product qualification rate and cost.

[0004] Therefore, how to reduce the processing difficulty of the valve needle assembly while ensuring that the double valve needle electronic expansion valve is provided with a balance structure has become a technical problem to be solved in the field. UTILITY MODEL CONTENTS

[0005] The purpose of the utility model includes providing a valve needle assembly and double valve needle electronic expansion valve, which can reduce the processing difficulty of the valve needle assembly while ensuring that the double valve needle electronic expansion valve is provided with a balance structure, thereby improving the product qualification rate and reducing the cost.

[0006] The embodiments of the utility model can be implemented as follows:

[0007] In a first aspect, the utility model provides a valve needle assembly applied to a double valve needle electronic expansion valve, comprising a large valve needle and a small valve needle.

[0008] The large valve needle comprises a valve head and a valve cylinder formed in two parts;

[0009] The valve head has opposite first and second ends, the center of the first end is provided with a blind hole, the outer periphery of the blind hole is provided with a through hole, the side wall of the valve head is provided with a side hole communicating with the blind hole, and the opening of the blind hole is provided with a sealing cone surface;

[0010] The valve cylinder is cylindrical and has a mounting cavity;

[0011] The valve head is connected with the valve barrel at one side of the first end, so that the blind hole and the through hole are both communicated with the mounting cavity;

[0012] The small valve needle has a sealing end and a connecting end, which are located at opposite sides of the small valve needle;

[0013] The small valve needle is movably mounted in the mounting cavity, the sealing end corresponds to the sealing conical surface, and the connecting end extends out of the end of the valve barrel for connection with a driving assembly of a double-valve-needle electronic expansion valve;

[0014] The side wall of the mounting cavity is provided with a limiting ring table, and the side wall of the small valve needle is provided with an abutting table matched with the limiting ring table, so that after the small valve needle moves relative to the valve barrel, the abutting table can abut against the limiting ring table to drive the large valve needle to move.

[0015] In an optional embodiment, the valve head is partially inserted into the valve barrel and is welded to the valve barrel.

[0016] In an optional embodiment, the valve head is located at the first end and is provided with an insertion ring table.

[0017] The valve barrel is provided with an insertion ring groove at the outer periphery of the end close to the valve head, the insertion ring table is inserted into the insertion ring groove, and the insertion ring table is welded to the valve barrel.

[0018] In an optional embodiment, the end of the insertion ring table and the outer periphery of the insertion ring table and / or the outer periphery of the abutting region between the valve barrel and the insertion ring table are provided with a welding ring groove;

[0019] The valve barrel and the insertion ring table are welded at the welding ring groove.

[0020] In an optional embodiment, the depth of the insertion ring groove is greater than the protruding height of the insertion ring table;

[0021] The end of the valve barrel close to the valve head abuts against the first end of the valve head, and a welding gap is formed between the insertion ring table and the bottom wall of the insertion ring groove;

[0022] The valve barrel and the insertion ring table are welded at the welding gap.

[0023] In an optional embodiment, the limiting ring table is integrally formed with the valve barrel;

[0024] Or,

[0025] The limiting ring table is formed separately from the valve cylinder, one end of the valve cylinder is away from the valve head, and an assembly ring groove is arranged at the outer periphery of the mounting cavity, and the limiting ring table is assembled in the assembly ring groove.

[0026] In an optional embodiment, a balance cavity is recessed on one side of the connecting end of the small valve needle, and a first balance side hole in communication with the balance cavity is arranged on the side wall of one end of the small valve needle close to the sealing end.

[0027] When the sealing end moves to abut against the sealing conical surface, the first balance side hole is in communication with the through hole.

[0028] In an optional embodiment, a second balance side hole in communication with the balance cavity is arranged on the side wall of the small valve needle extending out of the valve cylinder portion.

[0029] In an optional embodiment, a balance notch is arranged on the side wall of the small valve needle, and the through hole is in communication with the balance notch when the sealing end of the small valve needle abuts against the sealing conical surface, so as to balance the pressure difference at both ends of the large valve needle and the small valve needle.

[0030] In a second aspect, the utility model provides a double valve needle electronic expansion valve, including valve seat, shell, drive assembly, spring and valve needle assembly of any one of preceding embodiments;

[0031] The valve seat is provided with an open assembly cavity at one end, and the bottom of the valve seat is provided with a flow-through port, and the side wall of the valve seat is provided with a communication hole in communication with the assembly cavity.

[0032] The valve needle assembly is assembled in the assembly cavity, and the large valve needle corresponds to the flow-through port.

[0033] The spring is sleeved on the large valve needle and configured to apply an elastic force to the large valve needle in the direction of the flow-through port.

[0034] The drive assembly is connected with the connecting end of the small valve needle and configured to drive the large valve needle and the small valve needle to move.

[0035] The shell covers the outside of the drive assembly.

[0036] The valve needle assembly and the double valve needle electronic expansion valve provided by the embodiments of the utility model have the following beneficial effects:

[0037] This application designs the large valve needle as a separate valve head and valve cylinder. Separate valve head molding facilitates the machining of blind holes, side holes, sealing cone surfaces, and through holes for balancing pressure differentials. After machining the valve head, the valve cylinder is then assembled with it, thus reducing the overall machining difficulty of the large valve needle. In particular, it allows for easier external machining of the blind holes, sealing cone surfaces, and through holes. Secondly, this separate molding process allows the valve cylinder to be machined from a hollow cylindrical material, reducing the amount of cutting during machining and improving machining efficiency. Most importantly, when the valve needle assembly is closed, the through hole connects the interior of the valve needle assembly to the flow port, thereby balancing the pressure differential across the valve needle assembly and reducing the mechanical resistance to opening the valve needle assembly. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a cross-sectional view of a dual-valve needle electronic expansion valve provided in this embodiment;

[0040] Figure 2 This is a cross-sectional view of the small valve needle relative to the large valve needle in the closed state of a valve needle assembly provided in this embodiment;

[0041] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the small valve needle relative to the large valve needle in the open state of the valve needle assembly.

[0042] Figure 4 for Figure 2 A partial cross-sectional view of the valve head of the valve needle assembly shown.

[0043] Figure 5 This is a cross-sectional view of another dual-valve needle electronic expansion valve provided in this embodiment;

[0044] Figure 6 for Figure 5 The diagram shows a cross-sectional view of the small valve needle relative to the large valve needle in the closed state of the valve needle assembly.

[0045] Figure 7 for Figure 5 A partial cross-sectional view of the valve head of the valve needle assembly shown.

[0046] Figure 8 forFigure 5 Structure diagram of a small valve needle of the valve needle assembly.

[0047] Icon: 100-valve needle assembly; 110-large valve needle; 111-valve head; 112-valve barrel; 113-first end; 114-second end; 115-blind hole; 116-through hole; 117-side hole; 118-sealing cone surface; 119-mounting cavity; 120-limit ring table; 121-first assembly ring table; 122-insertion ring table; 123-insertion ring groove; 124-welding ring groove; 125-welding gap; 130-small valve needle; 131-sealing end; 132-connection end; 133-abutment table; 134-balance cavity; 135-first balance side hole; 136-second balance side hole; 137-balance notch; 300-double valve needle electronic expansion valve; 310-valve seat; 311-assembly cavity; 312-flow-through port; 313-communication hole; 314-second assembly ring table; 320-housing; 330-driving assembly; 331-rotor; 332-nut block; 333-fixing member; 334-slotted guide; 335-fixing groove; 336-bearing; 340-spring. DETAILED DESCRIPTION

[0048] When the valve needle of the double valve needle electronic expansion valve is in a closed state, a high pressure difference (which can be up to 3-5 MPa) at both ends of the valve needle can generate a mechanical resistance of up to 15-20 N, resulting in an increase of more than 40% in the motor starting torque requirement compared with a normal pressure working condition, thereby affecting the response efficiency of the valve needle when it is opened. To solve this problem, a conventional design uses a pressure compensation structure provided on the valve needle, but this solution can significantly increase the processing difficulty of the valve needle assembly in the double valve needle electronic expansion valve, thereby affecting the qualification rate and cost of the product. How to reduce the processing difficulty of the valve needle assembly while ensuring that the double valve needle electronic expansion valve is provided with a balance structure has become a technical problem to be solved in the field.

[0049] The embodiment provides a valve needle assembly and a double valve needle electronic expansion valve, which can reduce the processing difficulty of the valve needle assembly while ensuring that the double valve needle electronic expansion valve is provided with a balance structure, thereby improving the qualification rate and reducing the cost of the product.

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. 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.

[0051] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the utility model.

[0052] It should be noted that: similar signs and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0053] In the description of the utility model, it should be explained that if the terms such as 'up', 'down', 'inner', 'outer' and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship of the utility model product in common use, it is only for the convenience of describing the utility model and simplifying the description, and it is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model.

[0054] In addition, if the terms 'first','second' and the like appear, they are only used for differentiation description, and cannot be understood as indicating or implying relative importance.

[0055] It should be noted that the features in the embodiments of the utility model can be combined with each other without conflict.

[0056] The overall structure, working principle and technical effects of the valve needle assembly and the double-valve needle electronic expansion valve provided by the utility model are described in detail below through embodiments and in combination with the drawings.

[0057] Please refer to Figure 1 And Figure 5 The embodiment provides a double-valve needle electronic expansion valve 300, the double-valve needle electronic expansion valve 300 has a valve needle assembly 100 formed by linkage of a large valve needle 110 and a small valve needle 130, the valve needle assembly 100 can realize high-precision dynamic regulation and control of refrigerant flow in the range of 0-100% opening degree, and is especially suitable for application scenes such as variable frequency air conditioners and the like which have strict requirements on energy efficiency ratio.

[0058] The double-valve-needle electronic expansion valve 300 comprises a valve seat 310, an outer shell 320, a driving assembly 330, a spring 340 and the valve needle assembly 100. The valve seat 310 is provided with an assembly cavity 311 with one end open, and the bottom of the valve seat 310 is provided with a flow-through opening 312, and the side wall of the valve seat 310 is provided with a communication hole 313 communicating with the assembly cavity 311. The valve needle assembly 100 is assembled in the assembly cavity 311 and corresponds to the flow-through opening 312. The spring 340 is sleeved on the valve needle assembly 100 and is configured to apply a spring force to the valve needle assembly 100 in the direction of the flow-through opening 312. The driving assembly 330 is connected with the valve needle assembly 100 and is configured to drive the valve needle assembly 100 to move to open or close the flow-through opening 312. The outer shell 320 covers the outside of the driving assembly 330.

[0059] Please refer to Figures 1 to 8 In the embodiment, the valve needle assembly 100 comprises a large valve needle 110 and a small valve needle 130. The large valve needle 110 comprises a valve head 111 and a valve cylinder 112 which are formed separately. The valve head 111 has opposite first and second ends 113 and 114, the center of the first end 113 is provided with a blind hole 115, the outer periphery of the blind hole 115 is provided with a through hole 116, the side wall of the valve head 111 is provided with a side hole 117 communicating with the blind hole 115, and the opening of the blind hole 115 is provided with a sealing taper surface 118. The valve cylinder 112 is in a cylindrical shape and has a mounting cavity 119. The valve head 111 is connected with the valve cylinder 112 on one side of the first end 113, so that the blind hole 115 and the through hole 116 both communicate with the mounting cavity 119. The small valve needle 130 has a sealing end 131 and a connecting end 132 which are located on opposite sides of the small valve needle 130. The small valve needle 130 is movably mounted in the mounting cavity 119, the sealing end 131 corresponds to the sealing taper surface 118, and the connecting end 132 extends out of the end of the valve cylinder 112 and is connected with the driving assembly 330. The side wall of the mounting cavity 119 is provided with a limiting ring table 120, and the side wall of the small valve needle 130 is provided with an abutting table 133 cooperating with the limiting ring table 120. After the small valve needle 130 moves relative to the valve cylinder 112, the abutting table 133 can abut against the limiting ring table 120 to drive the large valve needle 110 to move.

[0060] The embodiment sets the large valve needle 110 as a split body formed valve head 111 and valve cylinder 112. The split body formed valve head 111 can facilitate machining of the blind hole 115, side hole 117, sealing taper surface 118 and through hole 116. The valve head 111 is machined and then assembled with the valve cylinder 112, which can reduce the machining difficulty of the large valve needle 110. Especially, the blind hole 115, sealing taper surface 118 and through hole 116 can be machined externally, which is more convenient. Secondly, the split body machining can use hollow cylindrical material for the valve cylinder 112, which can reduce the cutting amount during machining, thereby improving the machining efficiency. Most importantly, when the valve needle assembly 100 is closed, the through hole 116 can communicate the inside of the valve needle assembly 100 with the flow passage 312, thereby balancing the pressure difference between the two ends of the valve needle assembly 100, which can reduce the mechanical resistance of the valve needle assembly 100 to open.

[0061] It should be noted that the valve head 111 needs to be machined with the blind hole 115, side hole 117, through hole 116 and sealing taper surface 118 at the opening of the blind hole 115. Split machining of the valve head 111 can avoid the influence of the valve cylinder 112 on machining. The sealing taper surface 118 is used for abutting sealing and has high machining precision requirements, which needs fine machining and grinding treatment, which can improve the sealing performance between the large valve needle 110 and the small valve needle 130. Split machining can facilitate fine machining of the sealing taper surface 118.

[0062] Please refer to Figures 1 to 7 In the embodiment, the spring 340 is sleeved on the outside of the large valve needle 110, the outside of the valve cylinder 112 is formed with a first assembly ring table 121, and the valve seat 310 is provided with a second assembly ring table 314. One end of the spring 340 abuts against the first assembly ring table 121, and the other end abuts against the second assembly ring table 314. The spring 340 applies a spring force to the large valve needle 110 in the direction of the flow passage 312. In the initial stage of driving the small valve needle 130 to move by the driving assembly 330, the driving assembly 330 drives the lower valve needle to move, and the large valve needle 110 does not move under the action of the spring 340. Until the small valve needle 130 moves to abut against the limiting table and abutting table 133, the small valve needle 130 will move with the large valve needle 110 to overcome the spring force of the spring 340.

[0063] When the large valve needle 110 and the small valve needle 130 are both in the closed state, the large valve needle 110 abuts against the valve seat 310 around the flow-through hole 312, and the through hole 116 is in communication with the flow-through hole 312. The small valve needle 130 abuts against the sealing cone surface 118 around the blind hole 115, thereby blocking the flow of refrigerant. When the large valve needle 110 and the small valve needle 130 are both in the closed state, the flow-through hole 312 and the mounting cavity 119 can be communicated by the through hole 116, and the through hole 116 is in communication with the top end of the valve needle assembly 100 through the gap between the large valve needle 110 and the small valve needle 130 or the balance flow channel provided in the small valve needle 130, so that the pressure difference between the two ends of the valve needle assembly 100 can be balanced, and the requirement of the valve needle assembly 100 on the opening force is reduced. In the initial stage of the driving assembly 330 driving the small valve needle 130 to move, the small valve needle 130 opens the large valve needle 110, and the refrigerant flows into the assembly cavity 311 through the communication hole 313, flows into the blind hole 115 through the side hole 117, flows into the mounting cavity 119 through the blind hole 115, and then flows out of the mounting cavity 119 to the flow-through hole 312 through the through hole 116. After the small valve needle 130 moves and drives the large valve needle 110 to move, the refrigerant flows into the assembly cavity 311 through the communication hole 313 and then directly flows out of the flow-through hole 312. Of course, in some other embodiments of the present application, the communication hole 313 can also be used as the inlet of the refrigerant, and the flow-through hole 312 can be used as the outlet of the refrigerant.

[0064] Please refer to Figures 1 to 8 In the embodiment, the valve head 111 is partially inserted into the valve cylinder 112 and is welded to the valve cylinder.

[0065] The valve head 111 and the valve cylinder 112 are inserted and assembled in the embodiment, which can facilitate positioning during welding.

[0066] Further, the valve head 111 is provided with an insertion ring table 122 at the first end 113. The valve cylinder 112 is provided with an insertion ring groove 123 around the outer periphery of the end close to the valve head 111, the insertion ring table 122 is inserted into the insertion ring groove 123, and the insertion ring table 122 is welded to the valve cylinder 112.

[0067] The insertion ring table 122 and the insertion ring groove 123 are provided, which can better achieve the preliminary fixation and positioning between the two.

[0068] Please refer to Figures 1 to 4 In an embodiment of the present application, the end of the insertion ring table 122 and the outer periphery of the insertion ring table 122 and / or the outer periphery of the region where the valve cylinder 112 abuts against the insertion ring table are provided with a welding ring groove 124. The valve cylinder 112 and the insertion ring table 122 are welded at the welding ring groove 124.

[0069] The welding ring groove 124 is arranged in the valve head 111 and the valve cylinder 112, and the welding seam formed by welding does not exceed the outer periphery of the valve cylinder 112, so that the valve cylinder 112 does not affect the movement of the side wall of the assembly cavity 311.

[0070] Please refer to Figure 5 and Figure 6 In another embodiment of the present application, the depth of the insertion ring groove 123 is greater than the protruding height of the insertion ring platform. The end of the valve cylinder close to the valve head 111 abuts against the first end 113 of the valve head 111, and the welding gap 125 is formed by the space between the insertion ring platform and the bottom wall of the insertion ring groove 123. The valve cylinder 112 and the insertion ring platform 122 are welded at the welding gap 125.

[0071] This embodiment forms the welding gap 125, and the valve head 111 and the valve cylinder 112 are welded through the welding gap 125, so that the welding seam formed by welding does not exceed the outer periphery of the valve cylinder 112, and does not affect the movement of the side wall of the installation cavity 119. The end of the valve cylinder close to the valve head 111 abuts against the first end 113 of the valve head 111, so that the positioning is achieved.

[0072] Please refer to Figure 4 and Figure 7 In this embodiment, the through hole 116 has a plurality of through holes 116 arranged on the periphery of the blind hole 115, and the recess is arranged on the second end 114 of the valve head 111, and the through holes 116 are connected by the recess.

[0073] Please refer to Figures 1 to 3 In this embodiment, the limiting ring platform 120 is integrally formed with the valve cylinder 112. In the valve needle assembly 100 of this structure, the small valve needle 130 is assembled in the valve cylinder 112 during assembly, and then the valve head 111 is welded on the end of the valve cylinder 112. Integrally forming the limiting ring platform 120 with the valve cylinder 112 can reduce the number of parts of the valve needle assembly 100.

[0074] Please refer to Figure 5 and Figure 6 In some other embodiments of the present application, the limiting ring platform 120 is formed separately from the valve cylinder 112, and the end of the valve cylinder 112 away from the valve head 111 is provided with an assembly ring groove on the outer periphery of the installation cavity 119, and the limiting ring platform 120 is assembled in the assembly ring groove.

[0075] The limiting ring table 120 is formed separately from the valve cylinder 112 in this embodiment, which facilitates the machining of the valve cylinder 112. During assembly, the valve head 111 can be assembled on the valve cylinder 112, and then the small valve needle 130 is installed in the installation cavity 119 from the side of the opening of the installation cavity 119, and then the limiting ring table 120 is installed in the assembly ring groove and welded with the valve cylinder 112. The assembly of the assembly ring groove facilitates the positioning during the assembly of the limiting ring table 120.

[0076] Please refer to Figures 1 to 8 In this embodiment, a balance cavity 134 is recessed on one side of the connecting end 132 of the small valve needle 130, and a first balance side hole 135 is arranged on the side wall of the end of the small valve needle 130 close to the sealing end 131 and communicates with the balance cavity 134. When the sealing end 131 moves to abut against the sealing cone surface 118, the first balance side hole 135 communicates with the through hole 116.

[0077] In this embodiment, the small valve needle 130 is provided with a balance cavity 134, and a first balance hole is arranged on the side wall of the bottom end of the small valve needle 130. When both the large valve needle 110 and the small valve needle 130 are in the closed state, the through hole 116 communicates the flow passage 312 with the installation cavity 119, and the first balance hole communicates the installation cavity 119 with the balance cavity 134, and then with the top end of the small valve needle 130, so as to balance the pressure difference.

[0078] In this embodiment, a second balance side hole 136 is arranged on the side wall of the part of the small valve needle 130 extending out of the valve cylinder 112 and communicates with the balance cavity 134. The arrangement of the second balance side hole 136 can balance the pressure difference between the two ends of the large valve needle 110.

[0079] Please refer to Figures 5 to 8 In this embodiment, a balance notch 137 is arranged on the side wall of the small valve needle 130, and when the sealing end 131 of the small valve needle 130 abuts against the sealing cone surface 118, the through hole 116 communicates with the balance notch 137 to balance the pressure difference between the two ends of the large valve needle 110 and the small valve needle 130.

[0080] In this embodiment, a balance notch 137 is arranged on the side wall of the large valve needle 110, so that a balance flow channel is formed between the small valve needle 130 and the large valve needle 110, thereby balancing the pressure difference between the two ends of the valve needle assembly 100.

[0081] It should be noted that the balance notch 137 can be formed by grooving, planing or other processes or methods.

[0082] Of course, in some other embodiments of the present application, a flow groove can also be arranged on the side wall of the valve cylinder 112 to communicate the top end of the valve needle assembly 100 with the through hole 116 to balance the pressure difference.

[0083] Please refer to Figure 1 and Figure 5In the embodiment, the driving assembly 330 comprises a rotor 331, a nut block 332 and a fixing member 333. The bottom end of the fixing member 333 is provided with a sliding groove 334, the nut block 332 is installed in the sliding groove 334, the sliding groove 334 can limit the rotation of the nut block 332, and the top end of the fixing member 333 is provided with a fixing groove 335 in communication with the sliding groove 334. The rotor 331 is installed in the fixing groove 335 through a bearing 336, and the rotor shaft of the rotor 331 is in driving connection with the nut block 332 through threads. The nut block 332 is connected with the connecting end 132 of the small valve needle 130. The fixing member 333 is installed at the top end of the valve seat 310. The rotation of the rotor 331 can drive the nut block 332 to move along the sliding groove 334, thereby driving the small valve needle 130 to move. The shell 320 is arranged outside the rotor 331 and the fixing member 333, and is welded with the valve seat 310. The coil is arranged outside the shell 320 and corresponds to the rotor 331.

[0084] In summary, in the embodiment, the large valve needle 110 is formed in a split manner into a valve head 111 and a valve cylinder 112. The split forming of the valve head 111 can facilitate the machining of the blind hole 115, the side hole 117, the sealing conical surface 118 and the through hole 116 for balancing pressure difference on the valve head 111. After the machining of the valve head 111 is completed, the valve cylinder 112 is assembled with the valve head 111, so that the machining difficulty of the large valve needle 110 can be reduced as a whole. Especially, the blind hole 115, the sealing conical surface 118 and the through hole 116 can be machined externally, which is more convenient. Secondly, the split forming machining can use a hollow cylindrical material for the valve cylinder 112, so that the cutting amount during machining can be reduced, thereby improving the machining efficiency. Most importantly, when the valve needle assembly 100 is closed, the through hole 116 can communicate the inside of the valve needle assembly 100 with the flow passage 312, so that the pressure difference between the two ends of the valve needle assembly 100 can be balanced, and the mechanical resistance for opening the valve needle assembly 100 can be reduced.

[0085] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A valve needle assembly for a dual valve needle electronic expansion valve, characterized by, The big valve needle (110) and the small valve needle (130) are included. The big valve needle (110) includes a valve head (111) and a valve cylinder (112) which are formed separately. The valve head (111) has opposite first end (113) and second end (114), the center of the first end (113) is provided with a blind hole (115), the outer periphery of the blind hole (115) is provided with a through hole (116), the side wall of the valve head (111) is provided with a side hole (117) which communicates with the blind hole (115), the opening of the blind hole (115) is provided with a sealing cone surface (118). The valve cylinder (112) is cylindrical and has a mounting cavity (119). The valve head (111) is connected with the valve cylinder (112) on one side of the first end (113), so that the blind hole (115) and the through hole (116) both communicate with the mounting cavity (119). The small valve needle (130) has a sealing end (131) and a connecting end (132), and the sealing end (131) and the connecting end (132) are located on opposite sides of the small valve needle (130). The small valve needle (130) is movably installed in the mounting cavity (119), the sealing end (131) corresponds to the sealing cone surface (118), and the connecting end (132) is protruded from the end of the valve cylinder (112) for connecting with the driving assembly (330) of the double valve needle electronic expansion valve. The side wall of the mounting cavity (119) is provided with a limiting ring table (120), and the side wall of the small valve needle (130) is provided with an abutting table (133) matched with the limiting ring table (120), after the small valve needle (130) moves relative to the valve cylinder (112), the abutting table (133) can abut against the limiting ring table (120) to drive the big valve needle (110) to move.

2. The valve needle assembly of claim 1, wherein The valve head (111) is partially inserted into the valve cylinder and is welded with the valve cylinder.

3. The valve needle assembly of claim 2, wherein The valve head (111) is located at the first end (113) and is provided with an insertion ring table (122). The outer periphery of the end of the valve cylinder (112) close to the valve head (111) is provided with an insertion ring groove (123), the insertion ring table (122) is inserted into the insertion ring groove (123), and the insertion ring table (122) is welded with the valve cylinder (112).

4. The valve needle assembly of claim 3, wherein The end of the insertion ring table (122) and the outer periphery of the insertion ring table (122) and / or the outer periphery of the abutting area between the valve cylinder (112) and the insertion ring table (122) are provided with a welding ring groove (124). The valve cylinder (112) and the insertion ring table (122) are welded at the welding ring groove (124).

5. The valve needle assembly of claim 3, wherein The depth of the insertion ring groove (123) is greater than the protruding height of the insertion ring table (122). The end of the valve cylinder (112) close to the valve head (111) abuts against the first end (113) of the valve head (111), and the interval between the insertion ring table and the bottom wall of the insertion ring groove (123) forms a welding gap (125). The valve cylinder (112) and the insertion ring table (122) are welded at the welding gap (125).

6. The valve needle assembly of any of claims 1-5, wherein, The limiting ring table (120) is integrally formed with the valve cylinder (112); Or, The limiting ring table (120) is formed separately from the valve cylinder (112), and an assembly ring groove is arranged at the outer periphery of the valve cylinder (112) away from the valve head (111) and located in the mounting cavity (119), and the limiting ring table (120) is assembled in the assembly ring groove.

7. The valve needle assembly of any of claims 1-5, wherein, A balance cavity (134) is arranged on one side of the connecting end (132) of the small valve needle (130), and a first balance side hole (135) in communication with the balance cavity (134) is arranged on the side wall of one end of the small valve needle (130) close to the sealing end (131). When the sealing end (131) moves to abut against the sealing conical surface (118), the first balance side hole (135) is in communication with the through hole (116).

8. The valve needle assembly of claim 7, wherein, A second balance side hole (136) in communication with the balance cavity (134) is arranged on the side wall of the part of the small valve needle (130) extending out of the valve cylinder (112).

9. The valve needle assembly of any of claims 1-5, wherein, A balance notch (137) is arranged on the side wall of the small valve needle (130), and when the sealing end (131) of the small valve needle (130) abuts against the sealing conical surface (118), the through hole (116) is in communication with the balance notch (137) to balance the pressure difference at both ends of the large valve needle (110) and the small valve needle (130).

10. A dual-valve needle electronic expansion valve characterized by, The valve needle assembly comprises a valve seat (310), a housing (320), a driving assembly (330), a spring (340) and the valve needle assembly of any one of claims 1-9; The valve seat (310) is provided with an open-ended assembly cavity (311), and the bottom of the valve seat (310) is provided with a flow-through opening (312), and the side wall of the valve seat (310) is provided with a communication hole (313) in communication with the assembly cavity (311); The valve needle assembly is assembled in the assembly cavity (311), and the large valve needle (110) corresponds to the flow-through opening (312), The spring (340) is sleeved on the large valve needle (110) and configured to apply an elastic force to the large valve needle (110) in the direction of the flow-through opening (312); The driving assembly (330) is connected with the connecting end (132) of the small valve needle (130) and configured to drive the large valve needle (110) and the small valve needle (130) to move; The housing (320) covers the outside of the driving assembly (330).

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