Motor-driven two-dimensional digital valve

Abstract

The invention belongs to the field of fluid machinery, and discloses a motor-driven two-dimensional digital valve, which comprises a valve body, a valve core, a transmission assembly, a stepping motor and a stepping motor mounting shell, the valve core is inserted into the valve body, the stepping motor is mounted in the stepping motor mounting shell, the stepping motor is connected with the transmission assembly, the transmission assembly is connected with the valve core, and the valve core is connected with the stepping motor mounting shell. The stepping motor drives the valve element to rotate in the valve body through the transmission assembly, so that the valve element and the valve body complete flow distribution work, the transmission assembly comprises a stepping motor switching block, a deflector rod and a first elastic piece, the stepping motor switching block is connected with an output shaft of the stepping motor, one end of the deflector rod is connected with the stepping motor switching block, and the other end of the deflector rod is connected with the valve element. The transmission assembly is designed to have a large transmission ratio, and through the arrangement of the large transmission ratio, the out-of-step possibility of the stepping motor in the operation process is remarkably reduced.

Description

Technical Field

[0001] The invention relates to the field of fluid machinery, and in particular to a motor-driven two-dimensional digital valve. Background Art

[0002] In the 1980s, Ruan Jian proposed a new design method for hydraulic valves. Unlike traditional hydraulic valves that only use the single degree of freedom of rotation or sliding of the valve core, this method uses the dual degrees of freedom of rotation and sliding of a single valve core to integrate several hydraulic valves with different functions to form a new type of hydraulic valve, namely a two-dimensional (2D) valve. The two-dimensional flow servo valve is a typical representative of this. Its structural feature is that two parallel rotary valves are integrated at the shoulder position of one end of the valve core as the pilot stage. It consists of a high-pressure hole, a low-pressure hole and an inclined groove on the valve sleeve. The high-pressure hole is connected to the high-pressure port through the internal channel of the valve core rod; the low-pressure hole is connected to the oil return port; the inclined groove is in the middle of the high-pressure and low-pressure holes and leads to the sensitive cavity; the valve right cavity P port is connected, and the high-pressure oil of the P port is introduced and acts on the end face of the annular valve core (whose area is half of the cross-sectional area of ​​the valve core), generating a static pressure thrust to the left. Under the condition that the valve core maintains axial force balance, the pressure of the sensitive cavity is half of the pressure of the high-pressure P port. At this time, the size of the pilot valve opening (actually zero coverage) between the high-pressure and low-pressure holes and the inclined groove is exactly equal. When the valve core is rotated, the pilot valve opening changes, the pressure of the valve sensitive cavity changes, the axial force of the valve core loses balance and produces axial movement, and the feedback of the inclined groove makes it return to the middle of the high-pressure and low-pressure holes. The pressure of the sensitive cavity is restored to half of the pressure of the high-pressure P port, the axial force balance of the valve core stops moving, and the main valve forms an opening proportional to the rotation angle. The two-dimensional flow servo valve has a simple structure and its power density is significantly improved compared with the existing direct-drive valve or two-stage servo valve of the same level of pressure and flow.

[0003] Electro-hydraulic digital control valve, referred to as digital valve, is a hydraulic valve that uses digital signals to directly control the pressure, flow and direction of liquids. There are many types of digital valves, which are a new type of hydraulic component formed by combining various hydraulic valves with stepper motors or high-speed switches. There are many types of digital valve structures in the world. According to the valve core structure, there are rotary valves and slide valves; according to the working process, there are single-stage and double-stage; according to the feedback form, there are direct position feedback and electrical feedback; according to different control methods, electro-hydraulic digital valves can be divided into incremental digital valves and pulse width modulation high-speed switch digital valves.

[0004] The incremental digital valve is the most studied digital valve structure at home and abroad. Most of the digital valves that have been transformed into products are of this structure. The reason is that the stepper motor as the driving mechanism of the digital valve has some special advantages: (1) The stepper motor itself is a digital component, which facilitates connection with a computer interface, simplifies the valve structure, and reduces costs.

[0005] (2) Stepper motors have no cumulative error and good repeatability. When using a subdivided drive circuit, theoretically any level of positioning accuracy can be achieved. For example, the positioning accuracy of the stepper digital valves developed by Tokyo Keiki Co., Ltd., Guangzhou Machine Tool Research Institute, and Xi'an Jiaotong University all reached 0.1%.

[0006] (3) The stepper motor has almost no hysteresis error, so the hysteresis error of the entire valve is very small. The hysteresis errors of the digital valves of the above three companies are all within 0.5%.

[0007] (4) The control signal of the stepper motor is a pulse logic signal, so the reliability and anti-interference ability of the entire valve are better than those of the corresponding proportional valve and servo valve.

[0008] (5) The incremental digital valve has no special requirements for the valve body and can use the valve body of the existing proportional valve or conventional valve.

[0009] The zero position of the valve refers to the position of the valve core when the control signal input is "zero". For digital valves without position feedback and with a motor as an electro-mechanical converter, the zero position is generally determined in three ways: (1) For digital valves with mechanical reset, the valve core position when the power is off is the zero position, and the valve core is driven back to the center by the elastic element (or magnetic element) when the power is off. It is characterized by high reliability, but the structure is relatively complex. It is relatively simple to implement in valves with only two working positions and a small motor rotation angle, but it is difficult to implement when the motor rotation angle is large or the valve zero position is not at a certain extreme position; (2) When the power is off, the program is called to drive the controller to send a reset signal by relying on the small amount of electric energy stored in the capacitor on the controller, so that the stepper motor is reset to the initial state. The disadvantage is that it cannot guarantee the reliable reset of the motor when the power is suddenly off, unless a large capacitor or power supply is installed to store electric energy, but this will cause the controller to be abnormally bloated; (3) Each time the system is started, the stepper motor is controlled to move to a specific position for recalibration. This method of determining the zero position may cause the system to malfunction.

[0010] In addition, the driving motor used in digital valves is generally a dry motor, and the motor shaft and the valve core extension rod are contact transmission, which requires a sealing structure to be installed on the valve core extension rod or the motor shaft to avoid leakage. For some digital valves with both rotating and sliding seals, the reliability of the sealing structure is more important. The sealing reliability between the valve core and the outside world is also one of the main reasons why motor-driven digital valves are difficult to promote. Summary of the invention

[0011] The object of the present invention is to provide a motor-driven two-dimensional digital valve to solve the problems raised in the above-mentioned background technology.

[0012] To achieve the above object, the present invention provides the following technical solutions: A motor-driven two-dimensional digital valve comprises a valve body, a valve core, a transmission assembly, a stepper motor and a stepper motor mounting housing, wherein the valve core is inserted into the valve body, the valve core can rotate circumferentially and slide axially relative to the valve body, the stepper motor is mounted in the stepper motor mounting housing, the stepper motor is connected to the transmission assembly, the transmission assembly is connected to the valve core, the stepper motor drives the valve core to rotate in the valve body through the transmission assembly, so that the valve core and the valve body complete the flow distribution work, characterized in that the transmission assembly comprises a stepper motor adapter block, a lever and a first elastic member, the stepper motor adapter block is connected to the output shaft of the stepper motor, one end of the lever is connected to the stepper motor adapter block, and the other end is connected to the valve core, the output shaft of the stepper motor drives the stepper motor adapter block to rotate, when the stepper motor adapter block rotates, the lever drives the lever to rotate with the axis of the valve core as the center, the lever drives the valve core to rotate in the valve body, and the first elastic member acts on the stepper motor adapter block to restore the stepper motor adapter block to zero position after rotation.

[0013] Furthermore, the first elastic member is a torsion spring having torsion spring connecting ends on both sides, and the stepper motor adapter block has stepper motor adapter block limiters on both sides respectively abutting against the torsion spring connecting ends, and the two torsion spring connecting ends are sandwiched between the two stepper motor adapter block limiters.

[0014] Furthermore, it also includes two fixedly arranged torsion spring limiters, two torsion spring connecting ends are located in the middle of the torsion spring limiters, and the two torsion spring connecting ends are respectively against the torsion spring limiters on the same side.

[0015] Furthermore, a movable opening is provided on the lever, the stepper motor adapter block is located in the movable opening, the lever is connected to the stepper motor adapter block through the movable opening, and when the stepper motor adapter block rotates, the lever rotates by squeezing the side wall of the movable opening.

[0016] Furthermore, one end of the lever has a clamping opening for clamping the valve core, and the clamping opening is locked by a fastener to clamp the valve core.

[0017] Furthermore, a connecting plate is arranged between the valve body and the stepping motor mounting housing, and an aviation plug is arranged on the connecting plate.

[0018] Furthermore, a spring installation cavity is arranged between the valve body and the connecting plate, a first spring seat and a second spring seat are respectively sleeved on the valve core at the front and rear, a spring is arranged between the first spring seat and the second spring seat, the first spring seat and the second spring seat are located in the spring installation cavity, and the spring makes the first spring seat and the second spring seat respectively abut against the front and rear inner walls of the spring installation cavity; a retaining ring and a shoulder are respectively arranged on the front and rear outer wall of the valve core, the retaining ring abuts against the front side of the first spring seat, and the shoulder abuts against the rear side of the second spring seat.

[0019] Furthermore, a sealing plug and a first sealing ring are arranged between the front end of the valve core and the connecting plate, and a second sealing ring is arranged between the sealing plug and the valve core.

[0020] Furthermore, a rear end cover is provided at the rear end of the valve body.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1) The transmission assembly of the present invention is designed with a large transmission ratio. By setting the large transmission ratio, the possibility of the stepping motor losing step during operation is significantly reduced. The optimized design of the transmission assembly enables the digital proportional valve to operate stably under the open-loop control condition of the stepping motor, thereby improving the overall control accuracy and reliability of the system; 2) The present invention pre-tightens the torsion spring through the torsion spring limiters on both sides, and places the two stepper motor adapter block limiters of the motor adapter block on both sides of the torsion spring connection ends 700 at both ends of the pre-tightened torsion spring, so as to ensure that the spring torque that suddenly increases when the stepper motor deviates from the zero position needs to be overcome, thereby ensuring the bidirectional reliable return to zero of the stepper motor, and the reset torque can simultaneously meet the reset force required when the stepper motor rotates forward and reversely; 3. A spring is installed on the valve core after being pre-tightened by the valve core shoulder and the retaining ring. Both ends of the spring are in contact with the spring seat fixed on the valve body at the same time, so that the valve core can be guaranteed to receive a reset force that suddenly increases when it deviates from the zero position when it moves in both directions axially. This reset force ensures that the hydraulic valve is reliably in the valve core zero position when there is no oil flow, so as to avoid safety hazards such as malfunction of the system when the oil is suddenly passed; 4. The part of the valve core extending from the valve body is designed with a double sealing structure to ensure the sealing reliability of the entire valve; BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the invention structure.

[0023] Figure 2 It is a partial structural schematic diagram of the present invention.

[0024] Figure 3 It is a schematic diagram of the longitudinal cross-sectional structure of the present invention.

[0025] Figure 4 for Figure 3 Enlarged view of point A in the middle.

[0026] Figure 5 for Figure 3 Enlarged view of point B in the middle.

[0027] Figure 6 It is a schematic diagram of the connecting plate, the torsion spring mounting seat, and the torsion spring connecting structure in the present invention.

[0028] In the figure: valve body 1, valve core 2, shoulder 200, stepper motor 3, stepper motor mounting housing 4, stepper motor adapter block 5, lever 6, movable port 600, clamping mouth 601, first elastic member 7, torsion spring connecting end 700, stepper motor adapter block limiter 8, torsion spring limiter 9, connecting plate 10, aviation plug 11, spring mounting cavity 12, first spring seat 13, second spring seat 14, spring 15, retaining ring 16, first sealing ring 17, second sealing ring 18, rear end cover 19, sealing plug 20, torsion spring mounting seat 21. DETAILED DESCRIPTION

[0029] 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.

[0030] See also Figure 1-Figure 6 A motor-driven two-dimensional digital valve comprises a valve body 1, a valve core 2, a transmission assembly, a stepper motor 3, and a stepper motor mounting housing 4. The valve core 2 is inserted into the valve body 1, and the valve core 2 can rotate circumferentially and slide axially relative to the valve body 1. A rear end cover 19 is provided at the rear end of the valve body 1. The stepper motor 3 is mounted in the stepper motor mounting housing 4. The stepper motor 3 is connected to the transmission assembly, and the transmission assembly is connected to the valve core 2. The stepper motor 3 drives the valve core 2 to rotate in the valve body 1 through the transmission assembly, so that the valve core 2 and the valve body 1 complete the flow distribution work. The transmission assembly The system comprises a stepper motor adapter block 5, a lever 6 and a first elastic member 7. The stepper motor adapter block 5 is connected to the output shaft of the stepper motor 3. One end of the lever 6 is connected to the stepper motor adapter block 5, and the other end is connected to the valve core 2. The output shaft of the stepper motor 3 drives the stepper motor adapter block 5 to rotate. When the stepper motor adapter block 5 rotates, the lever 6 is driven to rotate with the axis of the valve core 2 as the center. The lever 6 drives the valve core 2 to rotate in the valve body 1. The first elastic member 7 acts on the stepper motor adapter block 5 to restore the stepper motor adapter block 5 to the zero position after rotation.

[0031] Continue reading Figure 2 The first elastic member 7 is a torsion spring, and the two sides of the torsion spring have torsion spring connection ends 700. The two sides of the stepper motor adapter block 5 respectively have stepper motor adapter block limiters 8 that abut against the torsion spring connection ends 700. The stepper motor adapter block limiter 8 is a pin structure, and the two torsion spring connection ends 700 are sandwiched between the two stepper motor adapter block limiters 8. The present invention also includes two fixedly arranged torsion spring limiters 9, the two torsion spring connection ends 700 are located in the middle of the torsion spring limiters 9, and the two torsion spring connection ends 700 are respectively abutted against the torsion spring limiters 9 on the same side, and the torsion spring limiters 9 are a pin structure.

[0032] Continue reading Figure 2 A movable opening 600 is provided on the lever 6, and the movable opening 600 is a runway-shaped structure. The stepper motor adapter block 5 is located in the movable opening 600, and the stepper motor adapter block 5 is an eccentric wheel or a cam. The lever 6 is connected to the stepper motor adapter block 5 through the movable opening 600. When the stepper motor adapter block 5 rotates, the lever 6 is rotated by squeezing the side wall of the movable opening 600, and the lever 6 can move axially on the stepper motor adapter block 5.

[0033] Continue reading Figure 2 One end of the lever 6 has a clamping opening 601 for clamping the valve core 2 , and the clamping opening 601 is locked by a fastener to clamp the valve core 2 .

[0034] Continue reading Figure 3 and Figure 6 A connecting plate 10 is arranged between the valve body 1 and the stepper motor mounting housing 4, an air plug 11 is arranged on the connecting plate 10, and a torsion spring stopper 9 is fixedly mounted on the connecting plate 10 by screws. A torsion spring mounting seat 21 is also mounted on the connecting plate 10 on the side facing the stepper motor 3 by screws, the torsion spring mounting seat 21 is coaxially arranged with the output shaft of the stepper motor 3, and the torsion spring is sleeved on the torsion spring mounting seat 21.

[0035] Continue reading Figure 3 and Figure 4 A spring installation cavity 12 is provided between the valve body 1 and the connecting plate 10, and a first spring seat 13 and a second spring seat 14 are respectively sleeved on the valve core 2. The first spring seat 13, the second spring seat 14 and the valve core 2 are not fixed, and a spring 15 is provided between the first spring seat 13 and the second spring seat 14. The first spring seat 13 and the second spring seat 14 are located in the spring installation cavity 12, and the spring 15 makes the first spring seat 13 and the second spring seat 14 respectively abut against the inner walls of the front and rear sides of the spring installation cavity 12. A retaining ring 16 and a shoulder 200 are respectively protruded on the outer wall of the valve core 2, wherein the retaining ring 16 is embedded in the corresponding annular groove of the outer wall of the valve core 2, and abuts against the front side of the first spring seat 13, and the shoulder 200 is a boss structure processed by the valve core 2, and abuts against the rear side of the second spring seat 14.

[0036] Continue reading Figure 3 and Figure 5 A sealing plug 20 and a first sealing ring 17 are arranged between the front end of the valve core 2 and the connecting plate 10. The sealing plug 20 is threadedly matched with the connecting plate 10. A second sealing ring 18 is arranged between the sealing plug and the valve core 2. The sealing plug 20 and the sealing ring realize sealing of the oil.

[0037] In the present invention, the electro-mechanical converter uses a stepper motor 3, and the stepper motor 3 is connected to the valve core 2 through a motor adapter block 5, a torsion spring, and a lever 6; the output shaft of the stepper motor 3 is fixedly connected to the motor adapter block 5, and two symmetrical stepper motor adapter block limiters 8 on the motor adapter block 5 make the torsion spring connecting end 700 of the pre-tightened torsion spring just fit between the two stepper motor adapter block limiters 8, and the motor adapter block 5 is in contact with the lever 6 at the same time, and the lever 6 is fixedly connected to the valve core 2, so that the rotation of the stepper motor 3 drives the lever 6 to rotate and then controls the rotation of the valve core 2, and then the rotation angle of the stepper motor 3 is proportionally transmitted to the valve core 2. At the same time, the pre-tightening of the torsion spring is achieved by the contact between the stepper motor adapter block limiter 8 and the torsion spring limiter 9 at both ends, so that when the motor adapter block 5 rotates to the left, the right stepper motor adapter block limiter 8 drives the right torsion spring connection end 700 of the torsion spring to move to the left, and the left torsion spring connection end 700 of the torsion spring is blocked by the stepper motor adapter block limiter 8, and the torsion spring outputs a torque opposite to that of the stepper motor to act on the motor adapter block 5. The same is true when the motor rotates in the opposite direction.

[0038] When the motor loses power, the restoring force of the torsion spring will drive the stepper motor adapter block limiter 8 on the motor adapter block 5 back to the initial position, which can reset the lever 6 to the zero position. At the same time, the rotation angle of the valve core 2 also returns to the zero position, so that the flow returns to zero. Compared with electrical zeroing, the mechanical zeroing achieved by this structure has higher reliability and anti-interference ability than the external magnetic field interference that may cause abnormal readings of the position magnetic encoder and microcontroller program running away.

[0039] The valve body 1 is sealed on the left side by two seals, and is sealed by a sealing ring on the left side. A sealing plug 20 is used on the left side to be fixedly connected to the valve body 1 through threads, and a sealing ring and two sets of gaskets are used on the right side to ensure partial sealing of the valve.

[0040] It should be noted that the corresponding oil suction and discharge structures on the valve body 1 and the valve core 2 in the present invention and the flow distribution work achieved by the valve core 2 through rotation and reciprocating motion are all well-known technologies in the art, wherein the rotation of the valve core 2 is driven by a motor, and the reciprocating motion of the valve core 2 is achieved by hydraulic pressure. The structure and implementation principle of the valve core 2 and the valve body 1 refer to patent CN111457130B.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A motor-driven two-dimensional digital valve, comprising a valve body (1), a valve core (2), a transmission assembly, a stepper motor (3) and a stepper motor mounting housing (4), wherein the valve core (2) is inserted into the valve body (1), the valve core (2) can rotate circumferentially and slide axially relative to the valve body (1), the stepper motor (3) is mounted in the stepper motor mounting housing (4), the stepper motor (3) is connected to the transmission assembly, the transmission assembly is connected to the valve core (2), the stepper motor (3) drives the valve core (2) to rotate in the valve body (1) through the transmission assembly, so that the valve core (2) and the valve body (1) complete the flow distribution work, characterized in that: The transmission assembly comprises a stepper motor adapter block (5), a lever (6) and a first elastic member (7); the stepper motor adapter block (5) is connected to the output shaft of the stepper motor (3); one end of the lever (6) is connected to the stepper motor adapter block (5) and the other end is connected to the valve core (2); the output shaft of the stepper motor (3) drives the stepper motor adapter block (5) to rotate; when the stepper motor adapter block (5) rotates, the lever (6) is driven to rotate with the axis of the valve core (2) as the center; the lever (6) drives the valve core (2) to rotate in the valve body (1); the first elastic member (7) acts on the stepper motor adapter block (5) to restore the stepper motor adapter block (5) to a zero position after rotation.

2. A motor-driven two-dimensional digital valve according to claim 1, characterized in that: The first elastic member (7) is a torsion spring, and the two sides of the torsion spring have torsion spring connection ends (700), and the two sides of the stepping motor adapter block (5) respectively have stepping motor adapter block limiters (8) that abut against the torsion spring connection ends (700), and the two torsion spring connection ends (700) are sandwiched between the two stepping motor adapter block limiters (8).

3. A motor-driven two-dimensional digital valve according to claim 2, characterized in that: It also includes two fixedly arranged torsion spring limiters (9), two torsion spring connection ends (700) are located in the middle of the torsion spring limiters (9), and the two torsion spring connection ends (700) respectively abut against the torsion spring limiters (9) on the same side.

4. The motor-driven two-dimensional digital valve according to claim 1, characterized in that: The lever (6) is provided with an active opening (600), the stepping motor adapter block (5) is located in the active opening (600), the lever (6) is connected to the stepping motor adapter block (5) via the active opening (600), and when the stepping motor adapter block (5) rotates, the lever (6) is rotated by squeezing the side wall of the active opening (600).

5. A motor-driven two-dimensional digital valve according to claim 4, characterized in that: One end of the lever (6) has a clamping opening (601) for clamping the valve core (2); the clamping opening (601) is locked by a fastener, thereby clamping the valve core (2).

6. The motor-driven two-dimensional digital valve according to claim 1, characterized in that: A connecting plate (10) is provided between the valve body (1) and the stepping motor mounting housing (4), and an aviation plug (11) is provided on the connecting plate (10).

7. A motor-driven two-dimensional digital valve according to claim 6, characterized in that: A spring installation cavity (12) is arranged between the valve body (1) and the connecting plate (10); a first spring seat (13) and a second spring seat (14) are respectively sleeved on the valve core (2) at the front and rear; a spring (15) is arranged between the first spring seat (13) and the second spring seat (14); the first spring seat (13) and the second spring seat (14) are located in the spring installation cavity (12); the spring (15) causes the first spring seat (13) and the second spring seat (14) to respectively abut against the front and rear inner walls of the spring installation cavity (12); a retaining ring (16) and a shoulder (200) are respectively arranged on the front and rear outer walls of the valve core (2); the retaining ring (16) abuts against the front side of the first spring seat (13), and the shoulder (200) abuts against the rear side of the second spring seat (14).

8. The motor-driven two-dimensional digital valve according to claim 6, characterized in that: A sealing plug (20) and a first sealing ring (17) are arranged between the front end of the valve core (2) and the connecting plate (10), and a second sealing ring (18) is arranged between the sealing plug and the valve core (2).

9. The motor-driven two-dimensional digital valve according to claim 1, characterized in that: A rear end cover (19) is provided at the rear end of the valve body (1).

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