An electronic expansion valve capable of preventing thread from getting stuck

Abstract

The invention discloses an electronic expansion valve capable of preventing thread jamming, comprising a housing, a stator assembly arranged in the housing, and a valve seat arranged at the lower end of the housing, a rotor assembly being arranged inside the stator assembly, a magnetic isolation tube being sleeved on the outer side of the rotor assembly, a valve stem connected to the rotor assembly being arranged at the center of the valve seat, a valve needle assembly being arranged at the lower part of the valve seat, a screw rod portion at the lower end of the valve stem being threadedly connected to the valve needle assembly, a valve base being arranged at the lower end of the valve seat, a valve port corresponding to the valve needle assembly being arranged on the valve base, and an anti-jamming assembly being arranged inside the magnetic isolation tube, the anti-jamming assembly comprising a main bracket and a spiral guide rail sleeved on the outer side of the main bracket, a spiral sliding slip ring being arranged on the spiral guide rail, and a toggle portion for driving the slip ring to move being arranged on the rotor assembly. The invention adopts a new anti-thread jamming structure, has a long service life, a high structural integration, a small number of parts, is more convenient to assemble, is conducive to lightweight, and has a more advantageous cost.

Description

Technical Field

[0001] The invention relates to the field of expansion valves, in particular to an electronic expansion valve capable of preventing thread from getting stuck. Background Art

[0002] Energy conservation and emission reduction are urgent problems that humans need to solve today. The throttling device plays a key role in the refrigeration system. By selecting a suitable throttling mechanism to match the refrigeration system, the energy consumption of the entire refrigeration system can be reduced. The working principle of throttling is that when the refrigerant flows through the valve, the flow cross-section suddenly shrinks, the fluid flow rate accelerates, and the pressure drops, thereby achieving the function of regulating the flow, controlling the superheat and the evaporation liquid level. Therefore, the regulation of the flow of the throttling mechanism plays a very important role in energy conservation and consumption reduction of the refrigeration device. In some occasions where the load changes drastically or the operating conditions are wide, traditional throttling elements (such as capillaries, thermal expansion valves, etc.) can no longer meet the requirements of comfort and energy saving. The temperature sensing package of the thermal expansion valve has obvious delay characteristics, which makes it difficult to respond quickly and effectively to the flow change with the compressor displacement, which ultimately leads to the oscillation of the system regulation, causing the machine to operate unstably and even damage the compressor network. Therefore, the electronic expansion valve is gradually replacing the traditional throttling element. The electronic expansion valve is superior to the traditional throttling mechanism in superheat control (liquid level control) and flow regulation, and has a faster response speed, a wider adjustment range, and a more significant energy-saving effect, and has broad application prospects.

[0003] Since the refrigerant system has a large pressure difference between the high and low pressures on both sides of the inlet and outlet of the electronic expansion valve, the pressure difference acts on the valve needle of the electronic expansion valve, which increases the resistance of the valve needle's movement. When the electronic expansion valve needs to be opened again after being closed, the valve needle needs to overcome the large pressure difference resistance to open the refrigerant channel. The valve needle is not easy to open. If a motor with a larger torque is used to overcome the resistance, the volume of the electronic expansion valve coil will increase relatively, the control accuracy will decrease, the installation will be limited by space, the system power consumption will be large, and the cost will increase.

[0004] In addition, during the process of closing the expansion valve, the valve needle suddenly stops when encountering the lower stroke limit, generating a large inertial force, which causes the threads to jam and the axial force of the parts structure to be too large, resulting in the valve being unable to open. Therefore, the existing expansion valve needs to be improved. Summary of the invention

[0005] The present invention provides an electronic expansion valve capable of preventing thread jamming, adopts a new thread jamming prevention structure, has a long service life, a high structural integration, fewer parts, more convenient assembly, is conducive to lightweight, and has more cost advantages.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an electronic expansion valve capable of preventing thread from getting stuck, comprising a housing, a stator assembly arranged in the housing, and a valve seat arranged at the lower end of the housing, a rotor assembly is installed inside the stator assembly, a magnetic isolation tube is sleeved on the outer side of the rotor assembly, a valve stem connected to the rotor assembly is installed at the center of the valve seat, a valve needle assembly is installed at the lower part of the valve seat, a screw rod portion at the lower end of the valve stem is threadedly connected to the valve needle assembly, a valve base is installed at the lower end of the valve seat, a valve port corresponding to the valve needle assembly is arranged on the valve base, and the valve seat is characterized in that it also includes:

[0007] The anti-jamming component is located inside the magnetic isolation tube. The anti-jamming component includes a main bracket and a spiral guide rail sleeved on the outside of the main bracket. The spiral guide rail is provided with a spiral sliding slip ring. The rotor assembly is provided with a toggle part for driving the slip ring to move.

[0008] The valve needle assembly is provided with a balancing flow channel corresponding to the valve port, and the balancing flow channel is communicated with the upper cavity of the valve seat.

[0009] Preferably, the main bracket includes a shaft portion and a positioning plate located at the upper end of the shaft portion, and the positioning plate is connected to the magnetic isolation tube.

[0010] Preferably, a plurality of positioning grooves are provided on the outer side wall of the positioning plate, and a riveting portion corresponding to and matching the positioning grooves is provided on the outer surface of the magnetic isolation tube.

[0011] Preferably, a circle of truncated cones are arranged on the upper part of the shaft portion, an annular groove is formed between the truncated cones and the positioning plate, and the upper end clamping portion of the spiral guide rail is fixedly clamped in the annular groove.

[0012] Preferably, the middle portion of the valve stem is connected to the valve seat via a bearing, and the upper portion of the valve stem is a positioning rod, which is axially inserted into the shaft portion of the main bracket.

[0013] Preferably, the valve needle assembly comprises a valve needle and an inner nut arranged inside the valve needle, the inner nut is connected to the screw rod portion, a stop ring is installed at the upper end of the valve needle, the stop ring is embedded in the valve needle and the lower end is connected to the inner nut.

[0014] Preferably, inserts are provided on both sides of the stop ring, and the inserts are embedded in the grooves on both sides of the end of the valve needle, and a gap is left between the stop ring and the valve needle.

[0015] Preferably, an elastic member is installed between the lower end of the inner nut and the valve needle.

[0016] Preferably, limiting planes are arranged on both sides of the inner hole of the valve seat, the limiting planes are in contact with the plane on the outer wall of the valve needle, the bottom of the valve seat is provided with a first step surface and a second step surface from top to bottom, a sealing ring is installed in the first step surface, a main sealing ring is installed on the inner ring of the sealing ring, and a pressure ring for limiting the main sealing ring and the sealing ring is installed in the second step surface.

[0017] Preferably, the shifting part is a vertical rod arranged inside the rotor assembly, a bending part is arranged at the lower end of the slip ring, and the vertical rod abuts against the bending part.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The rotor assembly adopts the design of slip ring and spring guide rail, so that the valve has upper and lower limit protection when opening and closing, preventing the valve from being stuck at the upper and lower dead points.

[0020] 2. The electronic expansion valve is equipped with a magnetic isolation tube and a dynamic seal. The fluid medium can enter the upper cavity of the valve body through the position of the valve needle. The fluid medium will fill the upper cavity of the entire valve seat assembly, and the fluid medium will not leak, thereby reducing the pressure difference between the upper and lower sides of the valve needle, reducing the movement resistance of the valve needle, and maintaining the low-pressure section at the fluid outlet, which helps to balance the pressure between the upper and lower ends of the valve needle of the electronic expansion valve and reduce energy consumption.

[0021] 3. The structure has high integration, fewer parts, and more convenient assembly, which is conducive to lightweight and has more cost advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional exploded structural diagram of the present invention;

[0023] Figure 2 It is a partial half-section structural diagram of the first structure of the present invention;

[0024] Figure 3 A partial half-section structural diagram of the second structure of the present invention;

[0025] Figure 4 It is a three-dimensional structural diagram of the anti-stuck component of the present invention;

[0026] Figure 5 The figure is an external structural diagram of the magnetic isolation tube of the present invention;

[0027] Figure 6 It is a structural diagram of the installation of the anti-stuck component of the present invention;

[0028] Figure 7 It is a specific structural diagram of the anti-stuck component of the present invention;

[0029] Figure 8A half-section structural diagram of a rotor assembly of the present invention;

[0030] Fig. 9 A half-section structural diagram of a valve seat of the present invention;

[0031] Fig.10 A top view of the valve seat of the present invention;

[0032] Fig.11 It is a three-dimensional structural diagram of the valve needle assembly of the present invention;

[0033] Fig.12 It is a half-section structural diagram of the valve needle assembly of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figure 1-12 The present invention provides an electronic expansion valve capable of preventing thread jamming, comprising a housing 1, a stator assembly 2 arranged in the housing 1, and a valve seat 8 arranged at the lower end of the housing 1. The housing 1 is an injection molded part, which is injection molded by a plastic material. To protect the stator assembly, the stator assembly 2 is wrapped with rubber, and the rubber covering material outside the stator assembly 2 is TSG-30 / 4W.

[0036] The stator assembly 2 is internally installed with a rotor assembly 6, the outer side of the rotor assembly 6 is sleeved with a magnetic isolation tube 4, the magnetic isolation tube 4 is made of SUS304 deep drawing, the center of the valve seat 8 is installed with a valve stem 7 connected to the rotor assembly 6, the lower part of the valve seat 8 is installed with a valve needle assembly 9, the screw rod part 71 at the lower end of the valve stem 7 is threadedly connected with the valve needle assembly 9, the lower end of the valve seat 8 is installed with a valve base 10, and the valve base 10 is provided with a valve port corresponding to the valve needle assembly 9, and further includes:

[0037] The anti-stuck component 5 is located inside the magnetic isolation tube 4. The anti-stuck component 5 includes a main bracket 50 and a spiral guide rail 59 sleeved on the outside of the main bracket 50. The main bracket 50 can be an injection molded part made of PEEK. The PEEK material has good self-lubricating properties, strong wear resistance, and good mechanical properties. The top of the main bracket 50 is contoured with the inside of the magnetic isolation tube 4 to play a role in fixed guide compensation, which can better ensure the coaxiality of the sample after assembly. The spiral guide rail 59 is provided with a spiral sliding slip ring 56, and the rotor assembly 6 is provided with a toggle part 61 for driving the slip ring 56 to move. When the rotor assembly 6 and the valve stem 7 rotate, the slip ring 56 can be driven to slide in a spiral shape and rise and fall along the main bracket 50. When the upper end surface of the slip ring 56 contacts the spiral guide rail 59, the valve needle assembly 9 is at the lowest end, the valve opening is the smallest, and no liquid passes through the valve; when the lower end of the slip ring 56 contacts the lower end of the spiral guide rail 59, the valve needle assembly 9 is at the highest end, the valve opening is the largest, and the flow rate of liquid passing through the valve is the largest. Since the slip ring 56 will reach the limit position of movement before the thread is stuck, the thread between the valve needle assembly 9 and the valve stem 7 can be effectively avoided.

[0038] The rotor assembly 6 includes a magnetic rotor, a magnetic rotor support frame and a toggle part 61. The magnetic rotor support frame is injection molded on the valve stem 7, and the toggle part 61 is injection molded in the magnetic rotor support frame. The injection molding material is PPS+40% GF. The magnetic rotor is bonded to the magnetic rotor support frame. The bonding material is neodymium iron boron Nd2Fe14B. After the injection molding is completed, the rotor assembly 6 is magnetized and tested. A groove is opened on the valve stem 7 to match the shaft elastic retaining ring.

[0039] The shifting portion 61 is a vertical rod disposed inside the rotor assembly 6 . A bending portion 52 is disposed at the lower end of the slip ring 56 . The vertical rod abuts against the bending portion 52 .

[0040] The valve needle assembly 9 is provided with a balancing flow channel 92 corresponding to the valve port, and the balancing flow channel 92 is communicated with the upper cavity of the valve seat 8 .

[0041] The main bracket 50 includes a shaft portion 55 and a positioning plate 53 located at the upper end of the shaft portion 55. The positioning plate 53 is connected to the magnetic isolation tube 4. A plurality of positioning grooves 51 are arranged on the outer side wall of the positioning plate 53. The outer surface of the magnetic isolation tube 4 is provided with a riveted portion 41 corresponding to the positioning grooves 51 to prevent the main bracket 50 from rotating. A small groove is provided at the lower end of the shaft portion 55 for positioning and preventing errors during assembly.

[0042] A circle of truncated cones 54 are provided on the upper part of the shaft portion 55, and an annular groove 58 is formed between the truncated cone 54 and the positioning plate 53. The upper end clamping portion 57 of the spiral guide rail 59 is fixedly clamped in the annular groove 58, and the upper part of the spiral guide rail 59 is clamped and fixed in the annular groove 58.

[0043] The middle part of the valve stem 7 is connected to the valve seat 8 through the bearing 11, and the upper part of the valve stem 7 is a positioning rod 72, which is axially inserted into the shaft portion 55 of the main bracket 50. The main bracket 50 can guide the rotation of the valve stem 7 and play the same role as the bearing.

[0044] The valve needle assembly 9 includes a valve needle 93 and an inner nut 91 arranged inside the valve needle 93. The inner nut 91 is connected to the screw rod portion 71. A stop ring 12 is installed on the upper end of the valve needle 93. The stop ring 12 is embedded in the valve needle 93 and the lower end is connected to the inner nut 91. The stop ring 12 is made of stainless steel and has two legs at the lower part for cooperating with the two grooves on the inner nut 91, so that the inner nut 91 will not rotate significantly inside the valve needle 93 and can only move axially within a limited space.

[0045] In order to prevent the stop ring 12 from rotating, the two sides of the stop ring 12 are provided with inserts 121, and the inserts 121 are embedded in the embedding grooves 95 on both sides of the end of the valve needle 93. A gap 122 is left between the stop ring 12 and the valve needle 93. An elastic member 94 is installed between the lower end of the inner nut 91 and the valve needle 93. The elastic member 94 can be a disc spring or a spring (such as Figure 3 As shown in the figure, it plays a buffering role to prevent the valve needle 93 from suddenly stopping when encountering the lower stroke limit during the valve closing movement, generating a large inertia force, causing the threads to be stuck, and the axial force of the parts structure to be too large, resulting in the situation that the valve cannot be opened. At the same time, it ensures the sealing of the valve needle 93 and the valve seat 8, and also reduces the valve opening force required when opening the valve. Figure 2 As shown, when the elastic member 94 is a disc spring, a small shallow groove is provided on the lower end surface of the inner hole of the valve needle 93 to place the disc spring so that it will not move radially. A through hole is provided at the lower end of the inner nut 91 to balance the pressure inside and outside the valve and reduce the resistance during movement. The structure of the inner nut 91 helps to compensate for the coaxiality of the valve body structure and make the structural coaxiality better.

[0046] Limiting planes 83 are arranged on both sides of the inner hole of the valve seat 8, and the limiting planes 83 are in contact with the planes on the outer wall of the valve needle 93 to radially fix the valve needle so that the valve needle can only move axially. The bottom of the valve seat 8 is provided with a first step surface 81 and a second step surface 82 from top to bottom, and a sealing ring 14 is installed in the first step surface 81, and a main sealing ring 13 is installed on the inner ring of the sealing ring 14. A pressure ring 15 for limiting the main sealing ring 13 and the sealing ring 14 is assembled in the second step surface 82. The peripheral shoulders of the first step surface 81 and the second step surface 82 are chamfered to facilitate the installation of the sealing ring 14 and prevent the sealing ring 14 from mechanical damage. The main sealing ring 13 and the sealing ring 14 are used together to form a dynamic sealing combination, which increases the service life, improves the sealing performance, and prevents internal leakage inside the valve body. The main sealing ring 13 and the valve needle assembly 9 are interference fit.

[0047] During assembly, the rotor assembly 6 is placed in the valve seat 8, the valve stem 7 and the bearing 11 are loosely fitted, and the inner ring of the bearing 11 contacts the shaft shoulder of the valve stem 7. Then the retaining ring is pressed into the shaft shoulder formed by the screw and the ball bearing along the bottom end of the valve stem 7 to prevent the rotor assembly 6 from axial movement, and the retaining ring is installed in the retaining ring groove on the valve stem 7. After the valve needle assembly 9 is assembled, the annular seam welding is performed; the dynamic seal assembly is installed in the valve seat 8, and then the valve needle assembly 9 is passed through the dynamic seal assembly and assembled with the rotor assembly 6. The valve needle assembly 9 is threadedly connected to the valve stem 7. The valve base 10 and the valve seat 8 are tightly fitted and pressed.

[0048] The electronic expansion valve needs to be grounded, and the connecting collar is connected to the housing 1 by heat riveting, electrically connected to the housing 1, and the other end is fixed to the valve body. Thus, the grounding connection of the housing 1 is realized, and static electricity and magnetic fields are prevented from interfering with the transmission and feedback of control signals, and the operation of the stator assembly 2 is avoided.

[0049] Before the electronic expansion valve starts working, the fluid medium passes through the balance flow channel and then enters the upper cavity of the valve seat through the thread gap. Due to the presence of the magnetic isolation tube 4, the fluid medium will fill the entire upper cavity of the valve seat, thereby reducing the pressure difference between the upper and lower sides of the valve needle 93 and reducing the movement resistance of the valve needle 93. In addition, due to the presence of the main sealing ring 13 and the sealing ring 14, the fluid medium will not leak outward.

[0050] When the electronic expansion valve starts working, the liquid high-pressure fluid medium will reduce its pressure after passing through the valve port throttling, and become a gas-liquid mixed fluid medium, while releasing heat. The temperature-pressure sensor at the outlet will input the collected temperature signal and pressure signal into the controller, and the controller will output the signal to the electronic expansion valve after calculation according to the relevant control program, and control the current in the winding coil in the stator assembly 2 to change, thereby controlling the stator assembly 2 to generate a changing excitation magnetic field, and the rotor assembly 6 rotates under the action of the excitation magnetic field, thereby driving the valve stem 7 to move, and further driving the valve needle assembly 9 to move through the thread transmission, so as to realize the change of the opening of the electronic expansion valve port, and then achieve the purpose of regulating the flow and pressure of the fluid medium.

[0051] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed by the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electronic expansion valve capable of preventing thread jamming, comprising a housing (1), a stator assembly (2) arranged in the housing (1) and a valve seat (8) arranged at the lower end of the housing (1), a rotor assembly (6) being installed inside the stator assembly (2), a magnetic isolation tube (4) being sleeved on the outer side of the rotor assembly (6), a valve stem (7) connected to the rotor assembly (6) being installed at the center of the valve seat (8), a valve needle assembly (9) being installed at the lower part of the valve seat (8), a screw rod portion (71) at the lower end of the valve stem (7) being threadedly connected to the valve needle assembly (9), a valve base (10) being installed at the lower end of the valve seat (8), a valve port corresponding to the valve needle assembly (9) being provided on the valve base (10), and characterized in that: Also includes: An anti-jamming assembly (5) is located inside the magnetic isolation tube (4), the anti-jamming assembly (5) comprising a main bracket (50) and a spiral guide rail (59) sleeved on the outside of the main bracket (50), a spiral sliding slip ring (56) is arranged on the spiral guide rail (59), and a toggle portion (61) for driving the slip ring (56) to move is arranged on the rotor assembly (6); The valve needle assembly (9) is provided with a balancing flow channel (92) corresponding to the valve port, and the balancing flow channel (92) is connected to the upper cavity of the valve seat (8); The valve needle assembly (9) comprises a valve needle (93) and an inner nut (91) arranged inside the valve needle (93), wherein the inner nut (91) is connected to the screw rod (71), and a stop ring (12) is installed at the upper end of the valve needle (93), wherein the stop ring (12) is embedded in the valve needle (93) and the lower end is connected to the inner nut (91), and the lower part of the stop ring (12) has two legs for engaging with two grooves on the inner nut (91). The inner nut (91) is matched to prevent a large rotation inside the valve needle (93); blocks (121) are provided on both sides of the stop ring (12); the blocks (121) are embedded in the grooves (95) on both sides of the end of the valve needle (93); a gap (122) is left between the stop ring (12) and the valve needle (93); and an elastic member (94) is installed between the lower end of the inner nut (91) and the valve needle (93).

2. The electronic expansion valve capable of preventing thread jamming according to claim 1, characterized in that: The main support (50) comprises a shaft portion (55) and a positioning plate (53) located at the upper end of the shaft portion (55), and the positioning plate (53) is connected to the magnetic isolation tube (4).

3. The electronic expansion valve capable of preventing thread jamming according to claim 2, characterized in that: A plurality of positioning grooves (51) are arranged on the outer side wall of the positioning plate (53), and a riveting portion (41) corresponding to and matching the positioning grooves (51) is arranged on the outer surface of the magnetic isolation tube (4).

4. The electronic expansion valve capable of preventing thread jamming according to claim 3, characterized in that: A circle of truncated cones (54) are arranged on the upper part of the shaft portion (55), an annular groove (58) is formed between the truncated cone (54) and the positioning plate (53), and the upper end clamping portion (57) of the spiral guide rail (59) is fixedly clamped in the annular groove (58).

5. The electronic expansion valve capable of preventing thread jamming according to claim 2, characterized in that: The middle part of the valve stem (7) is connected to the valve seat (8) through a bearing (11), and the upper part of the valve stem (7) is a positioning rod (72) which is axially inserted into the shaft portion (55) of the main bracket (50).

6. The electronic expansion valve capable of preventing thread jamming according to claim 1, characterized in that: Limiting planes (83) are arranged on both sides of the inner hole of the valve seat (8), and the limiting planes (83) are in contact with the plane on the outer wall of the valve needle (93). The bottom of the valve seat (8) is provided with a first step surface (81) and a second step surface (82) from top to bottom. A sealing ring (14) is installed in the first step surface (81), and a main sealing ring (13) is installed on the inner ring of the sealing ring (14). A pressure ring (15) for limiting the main sealing ring (13) and the sealing ring (14) is installed in the second step surface (82).

7. The electronic expansion valve capable of preventing thread jamming according to claim 1, characterized in that: The shifting portion (61) is a vertical rod arranged inside the rotor assembly (6); a bending portion (52) is arranged at the lower end of the slip ring (56); and the vertical rod abuts against the bending portion (52).

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