A threaded transmission mechanism and an electric valve including the same

Abstract

A threaded transmission mechanism and an electric valve including the same, wherein the externally threaded component of the electric valve comprises an externally threaded member and a mounting seat, wherein the externally threaded member comprises a stepped semi-cylindrical base and an externally threaded rod, wherein the externally threaded rod is fixedly connected to the bottom of the base, and wherein the mounting seat and the base are in a stepped semi-cylindrical shape that cooperate with each other; wherein the mounting seat and the lower section of the base cooperate to form a transmission portion that is connected and cooperates with the rotor of the electric valve, wherein a semi-cylindrical portion integrally formed with the externally threaded rod is formed on the axial plane portion of the base, and a semi-circular groove that cooperates with the semi-cylindrical portion is formed on the mounting seat. The present invention ensures the positional accuracy and strength of the thread injection molding by providing a formed semi-cylindrical portion on the externally threaded member and controlling the length of the semi-cylindrical portion to be close to the length of the external thread. Furthermore, the mounting seat and the externally threaded member are provided with a semi-cylindrical boss and a semi-cylindrical groove that are axially convex and concavely engaged, thereby ensuring the coaxiality of the externally threaded member and the threaded seat.

Description

Technical Field

[0001] The present invention belongs to the technical field of refrigeration electric valves, and in particular relates to a threaded transmission mechanism and an electric valve comprising the mechanism. Background Art

[0002] Electric valves are primarily used in cooling or heating systems. By varying the flow area of ​​the valve port and interlocking with the variable-frequency compressor in the system, they control the refrigerant pressure in the cooling or heating system. Existing electric valves are typically driven by a stepper motor. A threaded mechanism converts the motor's rotational motion into linear motion, allowing the tapered valve core, elastically connected to the thread, to move closer to or further from the valve port. To ensure the flow regulation accuracy and operational stability of the electric valve, the manufacturing precision of the threaded structure is crucial. This is especially true when the threaded structure is molded, as its design directly impacts the manufacturing precision of the thread. The elastic connection between the thread and the valve core is also crucial, ensuring ease of installation. Furthermore, the rotational flexibility between the valve core and the threaded mechanism is a key design consideration.

[0003] CN202992194U discloses a novel threaded transmission mechanism: a rotor core divided into two halves is encased within a magnet to form an integral rotating rotor. This allows a half-threaded opening section to be machined along the axis of the half rotor core, matching the external threads of the support rod. A rotor core movable cavity section wider than the half-threaded opening section, a narrower valve needle shaft hole section, and a valve needle tail groove section wider than the valve needle shaft hole section are formed. The half-mounting hole formed by these sections is used to accommodate a support rod with upper and lower stoppers at its upper end and a valve needle with a shoulder. The upper and lower stoppers are then used between the rotating body and the support rod to achieve lifting and braking of the magnet and rotor core, eliminating the need for multiple parts to achieve upper and lower stops, as in current electronic expansion valves. This reduces the number of parts in the expansion valve, making the structure simpler and easier to assemble. While this threaded transmission mechanism reduces parts and achieves the goal of simplifying the threaded mechanism, it reduces thread manufacturing precision, especially since the internal thread is assembled from two halves. The assembly precision of the two further affects the dimensional accuracy of the thread, and the thread joint also affects the sliding friction coefficient of the thread. At the same time, the rotor core composed of two halves also has support rods, valve cores, springs and other components, which makes assembly very inconvenient, especially when there is pre-tightening force during spring assembly, making assembly even more difficult. Summary of the Invention

[0004] In view of the problems of difficult assembly and low thread precision in existing thread transmission mechanisms of electric valves, the present invention aims to provide a thread transmission mechanism and an electric valve including the mechanism.

[0005] To this end, the present invention adopts the following technical solution: a threaded transmission mechanism, comprising an internally threaded component and an externally threaded component, the externally threaded component and the internally threaded component are connected through threaded matching transmission, and is characterized in that the externally threaded component comprises an externally threaded component and a mounting seat, the externally threaded component comprises a stepped semi-cylindrical base and an externally threaded rod, the externally threaded rod is fixedly connected to the bottom of the base, and the mounting seat and the base are in a stepped semi-cylindrical shape that matches each other; the mounting seat and the lower section of the base cooperate to form a transmission part connected to the rotor of the electric valve, a semi-cylindrical part integrally formed with the externally threaded rod is formed on the axial plane portion of the base, and a semi-circular groove that matches the semi-cylindrical part is formed on the mounting seat.

[0006] As a supplement and improvement to the above technical solution, the present invention also includes the following technical features.

[0007] The length of the semi-cylindrical portion accounts for at least 40% of the sum of the lengths of the semi-cylindrical portion and the external threaded member. Preferably, the length of the semi-cylindrical portion is equal to or greater than the length of the external threaded rod.

[0008] The externally threaded rod and the semi-cylindrical portion are provided with a connected valve core hole, within which a valve core is disposed. The valve core is movably mounted. A spring hole communicating with the valve core hole is provided at the top of the semi-cylindrical portion. A spring and a gasket are sequentially disposed in the spring hole, and the valve core is connected to the gasket. The valve core, gasket, and spring are installed in the complete circular hole, resulting in a small degree of freedom after assembly, facilitating subsequent assembly and improving precision.

[0009] The top of the spring passes through the spring hole, and the top of the spring is supported by a circular hole formed by cooperating with semicircular grooves respectively formed on the top of the base and the top of the mounting seat, thereby further guiding the spring.

[0010] A radially projecting spring abutment is provided at the top of the axial plane of the mounting seat, and a groove is provided at the top of the base portion that mates with the spring abutment. The spring abutment abuts against the spring, compressing it and thereby tightening the valve core. The valve core and the externally threaded component form an elastic connection system, enabling the valve core to move slightly axially and rotate circumferentially.

[0011] The outer peripheries of the mounting seat and the upper section of the semi-cylindrical portion are provided with retaining spring grooves, and retaining springs are provided in the retaining spring grooves.

[0012] An electric valve including the threaded transmission mechanism includes a valve seat, a valve core, a motor rotor and a cover, wherein the cover is fixedly welded to the outer edge of the valve seat. It is characterized in that the electric valve also includes the threaded transmission mechanism, the transmission part of the external threaded component is fixedly connected to the motor rotor, and the bottom of the internal threaded component is fixedly connected to the valve seat.

[0013] There is a guide gap between the valve core and the external threaded part, and between the mounting seat and the vertical core shaft. The guide gap and the groove on the external threaded part form a gas-liquid balance channel between the internal cavity formed by the threaded transmission mechanism and the valve main cavity. The guide gap realizes the connection between the cavity of the internal threaded part and the valve cavity, thereby balancing the pressure of the internal threaded cavity.

[0014] A vertical core shaft is mounted on the top of the housing, and a core shaft guide hole is provided on the spring support portion to mate with the vertical core shaft. After the housing and valve seat are assembled, the core shaft guides the mounting seat. Since the motor rotor is mounted on the mounting seat, the vertical core shaft and the threaded transmission mechanism together form the rotor's guide system.

[0015] The top surface and top outer edge of the internal threaded component are provided with a first stop portion, the bottom of the mounting seat is cantilevered downward and forms a semi-annular cavity, and the top of the semi-annular cavity and the annular wall of the semi-annular cavity are provided with a second stop portion corresponding to the first stop portion one by one to limit the stroke of the valve core.

[0016] The external threads are injection molded using a rotary core-pulling process. This involves placing a threaded core in the mold cavity. After injection molding, the mold is rotated and pulled out to form the external threads. Because the external threads are integrally formed from the core, the threads are uniform, highly accurate, and easily sized.

[0017] The present invention can achieve the following beneficial effects: 1. By providing a semi-cylindrical portion on the external threaded part and controlling the length of the semi-cylindrical portion to be close to the length of the external thread, the positional accuracy and strength of the thread injection molding can be ensured. In addition, the mounting seat and the external threaded part are provided with semi-cylindrical bosses and semi-cylindrical grooves that fit together along the axial direction, which can ensure the coaxiality of the mounting of the external threaded part and the threaded seat. 2. The motor rotor of the present invention adopts external threads and core shafts for vertical guidance, ensuring that the rotor rotates smoothly with low noise and vibration. No corresponding extension is provided on the external threaded part to avoid excessive contact length between the external threaded part and the mounting seat, which would cause assembly interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention.

[0019] Figure 2 It is a schematic structural diagram of the external threaded part of the present invention.

[0020] Figure 3 It is a schematic cross-sectional structural diagram of the external threaded component of the present invention.

[0021] Figure 4 It is a structural schematic diagram of the mounting base of the present invention. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] like Figure 1-Figure 4 As shown, the threaded transmission mechanism of the electric valve of the present invention includes an internal threaded component 1 and an external threaded component, and the external threaded component and the internal threaded component are connected through threaded matching. The external threaded component includes an external threaded component 2 and a mounting seat 3. The external threaded component 2 includes a stepped semi-cylindrical base 15 and an external threaded rod 16. The external threaded rod 16 is fixedly connected to the bottom of the base. The mounting seat 3 and the base 15 are in a stepped semi-cylindrical shape that matches each other; the mounting seat 3 and the lower section of the base 15 cooperate to form a transmission part connected to the motor rotor 7 of the electric valve, and a semi-cylindrical portion 17 integrally formed with the external threaded rod is formed on the axial plane portion of the base 15, and a semicircular groove matching the semi-cylindrical portion 17 is formed on the mounting seat 3.

[0024] Further preferably, the length of the semi-cylindrical portion 17 is equal to or greater than the length of the externally threaded rod 16 .

[0025] Further preferably, a connected valve core hole 18 is provided on the external threaded rod 16 and the semi-cylindrical portion 17, a valve core 4 is arranged in the valve core hole, and the valve core 4 is movably installed in the valve core hole. A spring hole 19 connected to the valve core hole is provided at the top of the semi-cylindrical portion 17, and a spring 6 and a gasket 5 are arranged in the spring hole in sequence from top to bottom, and the valve core 4 is connected to the gasket 5.

[0026] Further preferably, the top of the spring 6 passes through the spring hole, and the top of the spring is supported by a circular hole formed by cooperating with semicircular grooves formed respectively on the top of the base 15 and the top of the mounting seat 3 .

[0027] Further preferably, a spring abutment portion 13 protruding radially is provided on the top of the axial plane of the mounting seat 3 , and an abutment groove cooperating with the spring abutment portion 13 is provided on the top of the base 15 .

[0028] Further preferably, a retaining spring groove is provided on the outer periphery of the mounting seat 3 and the upper portion of the semi-cylindrical portion 17 , and a retaining spring 14 is provided in the retaining spring groove.

[0029] The electric valve includes a valve seat 8, a valve core 4, a motor rotor 7, a threaded transmission mechanism, and a housing 9. The housing 9 is welded to the outer edge of the valve seat. The transmission portion of the externally threaded component is fixedly connected to the motor rotor 7, and the bottom of the internally threaded component 1 is fixedly connected to the valve seat 8. A guide gap 31 is defined between the valve core 4 and the externally threaded component 2, and between the mounting seat 3 and the externally threaded component 2. The guide gap and the groove on the externally threaded component form a gas-liquid equilibrium channel between the internal cavity formed by the threaded transmission mechanism and the valve main cavity 111. A vertical core shaft 10 is provided at the top of the housing 9, and a core shaft guide hole that mates with the vertical core shaft 10 is provided in the spring support portion 13. A first stopper 12 is provided on the top surface and outer edge of the internally threaded component 1. The bottom of the mounting seat 3 extends downwardly to form a semi-annular cavity. A second stopper 11, corresponding one-to-one with the first stopper 12, is provided on the top and annular wall of the semi-annular cavity.

[0030] The external thread and internal thread of the thread transmission mechanism of the present invention are both made of plastic injection molding, which has high efficiency and good consistency in part molding. PTFE lubricant can be added to the injection molding material to greatly reduce the running resistance of the thread. Both the external thread and the internal thread are integral tooth types, and the thread shape and dimensional accuracy are relatively good. The thread mechanism has high transmission accuracy and low friction resistance.

Claims

1. An electric valve including a threaded transmission mechanism, comprising a valve seat (8), a valve core (4), a motor rotor (7) and a cover (9), wherein the cover (9) is fixedly welded to the outer edge of the valve seat, and is characterized in that: The thread transmission mechanism includes an internal thread component (1) and an external thread component, the external thread component and the internal thread component are connected by threaded matching transmission, the external thread component includes an external thread component (2) and a mounting seat (3), the external thread component (2) includes a stepped semi-cylindrical base (15) and an external threaded rod (16), the external threaded rod (16) is fixedly connected to the bottom of the base, the mounting seat (3) and the base (15) are in a stepped semi-cylindrical shape that matches each other; the mounting seat (3) and the lower section of the base (15) cooperate to form a transmission part connected to the motor rotor (7) of the electric valve, a semi-cylindrical part (17) is formed on the axial plane part of the base (15) and is integrally formed with the external threaded rod, the length of the semi-cylindrical part (17) is equal to or greater than the length of the external threaded rod (16), and a semi-circular groove that matches the semi-cylindrical part (17) is formed on the mounting seat (3); The externally threaded rod (16) and the semi-cylindrical portion (17) are provided with a valve core hole (18) in communication, the valve core (4) is provided in the valve core hole, the valve core (4) is movably installed in the valve core hole, the top of the semi-cylindrical portion (17) is provided with a spring hole (19) in communication with the valve core hole, a spring (6) and a gasket (5) are sequentially provided in the spring hole from top to bottom, and the valve core (4) is connected to the gasket (5); The top of the spring (6) passes through the spring hole, and the top of the spring is supported by a circular hole formed by cooperating with semicircular grooves formed on the top of the base (15) and the top of the mounting seat (3); The top of the axial plane of the mounting seat (3) is provided with a spring abutment portion (13) protruding radially, and the top of the base (15) is provided with an abutment groove cooperating with the spring abutment portion (13); The outer periphery of the mounting seat (3) and the upper portion of the semi-cylindrical portion (17) is provided with a retaining spring groove, and a retaining spring (14) is provided in the retaining spring groove; the transmission portion of the externally threaded component is fixedly connected to the motor rotor (7), and the bottom of the internally threaded component (1) is fixedly connected to the valve seat (8); a vertical core shaft (10) is provided on the top of the cover shell (9), and a core shaft guide hole that cooperates with the vertical core shaft (10) is provided on the spring supporting portion (13).

2. The electric valve comprising a threaded transmission mechanism according to claim 1, characterized in that: There is a guide gap between the valve core (4) and the external threaded part (2) and between the mounting seat (3) and the vertical core shaft (10), and the guide gap and the groove on the external threaded part form a gas-liquid balance channel between the internal cavity formed by the threaded transmission mechanism and the valve main cavity.

3. The electric valve comprising a threaded transmission mechanism according to claim 1, characterized in that: The top surface and top outer edge of the internal threaded component (1) are provided with a first stop portion (12), the bottom of the mounting seat (3) is cantilevered downward and forms a semi-annular cavity, and the top of the semi-annular cavity and the annular wall of the semi-annular cavity are provided with a second stop portion (11) corresponding to the first stop portion (12).

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