A piston type electronic expansion valve

Abstract

The present invention belongs to the technical field of control valves, and specifically relates to a piston-type electronic expansion valve. The piston-type electronic expansion valve has a valve housing, and the valve housing has a power chamber, an overflow chamber, a liquid inlet chamber, and a liquid discharge chamber; a liquid inlet is provided on the wall of the liquid inlet chamber for liquid to flow in; a liquid discharge is provided on the wall of the liquid discharge chamber for liquid to be discharged; an overflow is provided on the wall of the overflow chamber for liquid to overflow, and an overflow valve is provided on the overflow passage; a first through hole is provided between the overflow chamber and the liquid inlet chamber, and a second through hole is provided between the liquid inlet chamber and the liquid discharge chamber; the first through hole and the second through hole have the same cross-sectional size and are arranged opposite to each other; a piston is slidably provided in the first through hole and the second through hole; a spiral groove is provided on the side wall of the piston, and the spiral groove is not connected to the front end face of the piston; a power assembly is provided in the power chamber, and the power assembly drives the piston to move forward and backward. The piston-type electronic expansion valve has convenient and accurate flow control, good reliability, low failure rate, and long service life.

Description

Technical Field

[0001] The invention belongs to the technical field of control valves, and in particular relates to a piston type electronic expansion valve. Background Art

[0002] In various refrigeration / heating equipment such as air conditioners, refrigerators, and heat pump water heaters, electronic expansion valves are usually used to regulate the flow of fluids.

[0003] Electronic expansion valves usually include a motor with a stepper motor and a valve body as an actuator. The valve body includes a valve body with a refrigerant flow inlet and a flow outlet, a valve core placed in the inner cavity of the valve body, and a valve core seat with a valve port. By inputting a pulse signal to the motor of the driving component, the valve core is driven to move relative to the valve port, thereby changing the refrigerant flow at the valve port, so as to adjust the refrigerant flow at the flow outlet to control the heat exchange balance in the air conditioner or refrigerator. Therefore, the flow curve in the electronic expansion valve is a key technical feature that directly determines the working efficiency of the refrigeration system.

[0004] In current electronic expansion valve products, when the coil is connected to current, a magnetic field is generated, causing the magnetostrictive material driving rod to extend, pushing the displacement transfer rod to move, and the displacement transfer rod pushes the valve stem to move around the rotating shaft, causing the distance between the valve stem and the liquid inlet to change. By adjusting the current in the coil, the distance between the valve stem and the liquid inlet can be adjusted, thereby controlling the flow of the refrigerant. Although this type of electronic expansion valve has a relatively low manufacturing cost and a simple structure, it has low control accuracy, poor sealing performance, and high energy loss. In the electronic expansion valve, the valve needle and the valve seat are repeatedly touched to achieve the opening and closing conversion, which is easy to cause deformation and damage to the contact part, resulting in unstable flow. Long-term contact may also cause a small amount of metal fragments and powder to peel off from the contact part, causing the valve needle to malfunction. In addition, at the moment of valve startup or locking, the "water hammer" effect of the liquid has a greater impact on the valve and pipeline, resulting in an increased failure rate and a serious limitation of the service life. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a piston-type electronic expansion valve.

[0006] The piston type electronic expansion valve provided by the present invention has a valve shell, which is divided into a plurality of chambers, including a power chamber, an overflow chamber, a liquid inlet chamber, and a liquid discharge chamber; a liquid inlet is provided on the chamber wall of the liquid inlet chamber for liquid to flow in; a liquid discharge is provided on the chamber wall of the liquid discharge chamber for liquid to be discharged; an overflow is provided on the chamber wall of the overflow chamber for liquid to overflow, and an overflow valve is provided on the overflow passage; a first through hole is provided between the overflow chamber and the liquid inlet chamber, and a second through hole is provided between the liquid inlet chamber and the liquid discharge chamber; the first through hole and the second through hole have the same cross-sectional size and are arranged opposite to each other; a piston is slidably provided in the first through hole and the second through hole; a spiral groove is provided on the side wall of the piston, and the spiral groove is not connected to the front end face of the piston; a power assembly is provided in the power chamber, and the power assembly drives the piston to move forward and backward. Among them, the movement direction of the piston when sliding into the liquid discharge chamber is recorded as the front, and the opposite direction is recorded as the rear.

[0007] When the piston-type electronic expansion valve is used, liquid flows into the liquid inlet cavity from the liquid inlet port, and the piston moves forward and backward. When the piston moves to the front position, the liquid in the liquid inlet cavity passes through the second through hole through the spiral groove and enters the liquid discharge cavity, and is discharged from the liquid discharge port. At this time, the valve is in the open state. When the piston moves to the rear position, the spiral groove exits the second through hole, the second through hole is filled by the piston, and the liquid in the liquid inlet cavity cannot enter the liquid discharge cavity. At this time, the valve is in the closed state. When the valve is suddenly closed, the piston moves quickly to the rear position, and the liquid from the liquid inlet pipe flows into the overflow cavity through the spiral groove under the action of inertia. As the pressure in the overflow cavity increases, the overflow valve opens and releases the pressure, thereby protecting the pipeline and valve structure. Since the spiral groove is arranged on the surface of the piston, the piston can be relatively accurately arranged in the first through hole and the second through hole, and no radial shaking will occur. Moreover, during the forward and backward movement of the piston, the wear of the inner surface of the first through hole and the second through hole and the outer surface of the piston is uniform, and no local severe wear will occur. Therefore, it can maintain a high matching accuracy during long-term use, and has a long service life and high reliability.

[0008] Furthermore, the front section of the spiral groove is an adjustment section, and the cross section of the adjustment section gradually decreases from the back to the front. Due to the existence of the adjustment section, when the piston moves forward and backward, the cross-sectional area of ​​the channel formed between the piston and the second through hole will change. Therefore, the flow rate of the liquid can be controlled by controlling the position of the piston. Preferably, the cross section of the adjustment section decreases linearly from the back to the front, thereby obtaining a relatively linear flow characteristic curve, so as to facilitate automatic and precise control.

[0009] Furthermore, a threaded hole extending forward is provided on the rear end face of the piston; a seal, such as a sealing ring, a stuffing box seal assembly, etc., is provided between the power chamber and the overflow chamber; a threaded shaft extends from the power chamber through the seal into the overflow chamber and is threadedly connected with the threaded hole; the power assembly drives the threaded shaft to rotate, thereby driving the piston to move forward and backward. Preferably, the portion of the threaded shaft located in front of the seal has an external thread, and other portions are not provided with an external thread.

[0010] Furthermore, the power assembly includes a driving wheel, a first driven wheel, a second driven wheel, a speed reducer, and a torque limiter; the two ends of the torque limiter are respectively connected to the output end of the speed reducer and the threaded shaft; the input end of the speed reducer is connected to the second driven wheel, and the first driven wheel is engaged with the second driven wheel and the driving wheel at the same time; the driving wheel is driven to rotate by the motor, and the motor can be installed inside or outside the power cavity. After the motor is energized, a rotational driving force is generated, which is transmitted to the threaded shaft in turn through the first driven wheel, the second driven wheel, the speed reducer, and the torque limiter. The rotation of the threaded shaft drives the piston to move, and controls the opening and closing of the valve and the opening degree. Among them, the speed reducer plays the role of reducing speed and increasing torque; the torque limiter slips when the torque is too large to protect the motor and the power assembly.

[0011] The reducer can be in many forms, for example, a planetary reducer can be used, which can be single-stage or multi-stage. The following uses a single-stage planetary reducer as an example to introduce a feasible method of use. The reducer includes an inner gear ring, a planet carrier, a planetary gear, and a sun gear; the inner gear ring is fixed in the power chamber, and a planet carrier and a sun gear are rotatably arranged in the inner gear ring. A group of planetary gears are arranged in an annular array on the planet carrier, and the inner gear ring is meshed around the planetary gears, and the sun gear is meshed in the center of the planetary gears; the planet carrier is connected to the torque limiter shaft, and the sun gear is connected to the second driven wheel shaft.

[0012] Furthermore, the overflow port is preferably connected to the drain cavity to form an overflow passage. When the valve is suddenly closed, a small amount of liquid overflowing from the overflow port can be directly introduced into the drain cavity, thereby preventing the "water hammer" effect. Of course, it can also be discharged to other places, such as setting up an additional storage tank or directly emptying (applicable to non-toxic and harmless media such as water).

[0013] Furthermore, the overflow valve is a one-way valve, and the liquid overflows when the pressure of the liquid in the overflow chamber exceeds the maximum limit pressure of the overflow valve.

[0014] Furthermore, the overflow valve includes a valve tube, a valve ball and a compression spring arranged in the valve tube; the valve tube is generally in the shape of a circular tube, and one end has a trumpet-shaped constriction, and the compression spring presses the valve ball into the trumpet-shaped constriction.

[0015] Beneficial effects: Compared with the prior art, the piston-type electronic expansion valve provided by the present invention has convenient and accurate flow control, good reliability, low failure rate and long service life. When it is working, the on-off and flow area of ​​the spiral groove are changed by the movement of the piston, and the flow rate can be accurately controlled. When it is working, the fluid control part does not collide, the fluid control part does not deform, and it is not easy to generate metal fragments. When it is working, the surface of each moving part wears evenly, there is no local concentrated wear, and it can maintain a high matching accuracy for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the internal structure of the present invention.

[0017] Figure 2 , 3 , 4 for Figure 1 The part is for reference only.

[0018] Figure 5 Schematic diagram of the piston structure.

[0019] Figure 6 It is a structural schematic diagram of the present invention in a closed state.

[0020] In the figure, valve housing 1, power chamber 11, overflow chamber 12, liquid inlet chamber 13, liquid discharge chamber 14, liquid inlet port 2, liquid discharge port 3, overflow port 4, overflow valve 41, first through hole 15, second through hole 16, piston 5, spiral groove 51, motor 8, power assembly 9, adjusting section 511, threaded hole 52, seal 6, threaded shaft 7, driving wheel 91, first driven wheel 92, second driven wheel 93, reducer 94, torque limiter 95, inner ring gear 941, planet carrier 942, planetary gear 943, sun gear 944, valve pipe 411, valve ball 412, and compression spring 413. DETAILED DESCRIPTION

[0021] The present invention is further illustrated by the following examples, which are intended to more clearly illustrate the technical solution of the present invention and should not be construed as a limitation.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood as the usual meanings understood by people with ordinary skills in the field. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example 1

[0024] A piston type electronic expansion valve, such as Figures 1 to 6 As shown, there is a valve housing 1, which is divided into a plurality of chambers, including a power chamber 11, an overflow chamber 12, a liquid inlet chamber 13, and a liquid discharge chamber 14; a liquid inlet port 2 is provided on the chamber wall of the liquid inlet chamber 13 for liquid to flow in; a liquid discharge port 3 is provided on the chamber wall of the liquid discharge chamber 14 for liquid to be discharged; an overflow port 4 is provided on the chamber wall of the overflow chamber 12 for liquid to overflow, and an overflow valve 41 is provided on the overflow passage; a first through hole 15 is provided between the overflow chamber 12 and the liquid inlet chamber 13, and a second through hole 16 is provided between the liquid inlet chamber 13 and the liquid discharge chamber 14; the first through hole 15 and the second through hole 16 have the same cross-sectional size and are arranged opposite to each other; a piston 5 is slidably provided in the first through hole 15 and the second through hole 16; a spiral groove 51 is provided on the side wall of the piston 5, and the spiral groove 51 is not connected to the front end surface of the piston 5; a power assembly 9 is provided in the power chamber 11, and the power assembly 9 drives the piston 5 to move forward and backward. The movement direction of the piston 5 when sliding into the discharge chamber 14 is recorded as the front direction, and the opposite direction is recorded as the rear direction.

[0025] In this embodiment, the front section of the spiral groove 51 is the adjustment section 511 , and the cross section of the adjustment section 511 gradually decreases from the back to the front.

[0026] In this embodiment, a threaded hole 52 extending forward is provided on the rear end surface of the piston 5; a seal 6 is provided between the power chamber 11 and the overflow chamber 12; a threaded shaft 7 extends from the power chamber 11 through the seal 6 into the overflow chamber 12 and is threadedly connected with the threaded hole 52; the power assembly 9 drives the threaded shaft 7 to rotate. The portion of the threaded shaft 7 located in front of the seal 6 has an external thread, and other portions are not provided with an external thread.

[0027] In this embodiment, the power assembly 9 includes a driving wheel 91, a first driven wheel 92, a second driven wheel 93, a reducer 94, and a torque limiter 95; the two ends of the torque limiter 95 are respectively connected to the output end of the reducer 94 and the threaded shaft 7; the input end of the reducer 94 is connected to the second driven wheel 93, and the first driven wheel 92 is engaged with the second driven wheel 93 and the driving wheel 91 at the same time; the driving wheel is driven to rotate by the motor 8.

[0028] In this embodiment, the reducer 94 is a planetary reducer, including an inner ring gear 941, a planet carrier 942, planetary wheels 943, and a sun wheel 944; the inner ring gear 941 is fixed in the power chamber 11, and the planet carrier 942 and the sun wheel 944 are rotatably provided in the inner ring gear 941, and a group of planetary wheels 943 are provided in a ring array on the planet carrier 942, the inner ring gear 941 is meshed around the planetary wheels 943, and the sun wheel 944 is meshed in the center of the planetary wheels 943; the planetary carrier 942 is connected to the shaft of the torque limiter 95, and the sun wheel 944 is connected to the shaft of the second driven wheel 93.

[0029] In this embodiment, the overflow port 4 is connected to the drainage cavity 14 to form an overflow passage.

[0030] In this embodiment, the overflow valve 41 is a one-way valve, which includes a valve tube 411, a valve ball 412 and a compression spring 413 disposed in the valve tube 411; the valve tube 411 is generally in the shape of a round tube, with a trumpet-shaped constriction at one end, and the compression spring 413 presses the valve ball 412 at the trumpet-shaped constriction.

[0031] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the present invention so that people familiar with the technology in this field can understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A piston type electronic expansion valve, Features: The valve housing (1) is provided with a plurality of chambers, including a power chamber (11), an overflow chamber (12), a liquid inlet chamber (13), and a liquid discharge chamber (14); a liquid inlet port (2) is provided on the chamber wall of the liquid inlet chamber (13) for liquid to flow in; a liquid discharge port (3) is provided on the chamber wall of the liquid discharge chamber (14) for liquid to be discharged; an overflow port (4) is provided on the chamber wall of the overflow chamber (12) for liquid to overflow, and an overflow valve (41) is provided on the overflow passage; a first through hole (11) is provided between the overflow chamber (12) and the liquid inlet chamber (13); 5), a second through hole (16) is provided between the liquid inlet chamber (13) and the liquid discharge chamber (14); the first through hole (15) and the second through hole (16) have the same cross-sectional size and are arranged opposite to each other; a piston (5) is slidably provided in the first through hole (15) and the second through hole (16); a spiral groove (51) is provided on the side wall of the piston (5), and the spiral groove (51) is not connected to the front end surface of the piston (5); a power assembly (9) is provided in the power chamber (11), and the power assembly (9) drives the piston (5) to move forward and backward; The direction of movement of the piston (5) when sliding into the liquid discharge chamber (14) is recorded as the forward direction, and the opposite direction is recorded as the backward direction; A front section of the spiral groove (51) is an adjustment section (511), and a cross section of the adjustment section (511) decreases linearly from the back to the front; The overflow port (4) is connected to the drainage cavity (14) to form an overflow passage.

2. The piston type electronic expansion valve according to claim 1, Features: A threaded hole (52) extending forward is provided on the rear end surface of the piston (5); a sealing member (6) is provided between the power chamber (11) and the overflow chamber (12); a threaded shaft (7) extends from the power chamber (11) through the sealing member (6) into the overflow chamber (12) and is threadedly connected to the threaded hole (52); and the power assembly (9) drives the threaded shaft (7) to rotate.

3. The piston type electronic expansion valve according to claim 2, Features: The power assembly (9) comprises a driving wheel (91), a first driven wheel (92), a second driven wheel (93), a reducer (94), and a torque limiter (95); two ends of the torque limiter (95) are respectively connected to the output end of the reducer (94) and the threaded shaft (7); the input end of the reducer (94) is connected to the second driven wheel (93), and the first driven wheel (92) is meshed with the second driven wheel (93) and the driving wheel (91) at the same time; the driving wheel is driven to rotate by the motor (8).

4. The piston type electronic expansion valve according to claim 3, Features: The reducer (94) is a planetary reducer, comprising an inner gear ring (941), a planet carrier (942), planetary wheels (943), and a sun wheel (944); the inner gear ring (941) is fixed in a power chamber (11), a planet carrier (942) and a sun wheel (944) are rotatably arranged in the inner gear ring (941), a group of planetary wheels (943) are arranged in an annular array on the planetary carrier (942), the inner gear ring (941) is meshed around the planetary wheels (943), and the sun wheel (944) is meshed in the center of the planetary wheels (943); the planetary carrier (942) is connected to the shaft of the torque limiter (95), and the sun wheel (944) is connected to the shaft of the second driven wheel (93).

5. The piston type electronic expansion valve according to claim 1, Features: The relief valve (41) is a one-way valve.

6. The piston type electronic expansion valve according to claim 5, Features: The overflow valve (41) comprises a valve tube (411), a valve ball (412) and a compression spring (413) arranged in the valve tube (411); the valve tube (411) is in the shape of a circular tube as a whole, and has a trumpet-shaped constriction at one end; the compression spring (413) presses the valve ball (412) against the trumpet-shaped constriction.

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