A dual-valve core rotary valve controlled stepper hydraulic motor

Abstract

A dual-spool rotary valve control type stepper hydraulic motor includes a dual-spool rotary valve, a synchronous belt transmission mechanism, a dual-shaft hydraulic motor, an angle sensor and an oil pipe. The dual-spool rotary valve includes a hollow stepper motor, a valve body, a passive valve core and an active valve core. The synchronous belt transmission mechanism includes a synchronous belt large wheel, a synchronous belt and a synchronous belt small wheel. The hollow stepper motor is connected to the active valve core of the dual-spool rotary valve, the passive valve core of the dual-spool rotary valve is connected to the synchronous belt large wheel, the output shaft at the rear end of the dual-shaft hydraulic motor is connected to the synchronous belt small wheel, the dual-shaft hydraulic motor forms mechanical negative feedback to the dual-spool rotary valve through the synchronous belt, and the angle sensor can not only monitor the angle of the dual-shaft hydraulic motor in real time, but also form electrical negative feedback of the dual-shaft hydraulic motor to the dual-spool rotary valve through an external controller. The stepper hydraulic motor has a simple structure, high reliability, low cost, and real-time monitoring of the operating status, and can perform electrical compensation for factors such as load changes, internal leakage and dead zones.

Description

Technical Field

[0001] The invention belongs to the technical field of electro-hydraulic control, and in particular relates to a double-valve core rotary valve controlled stepping hydraulic motor. Background Art

[0002] Hydraulic motors are widely used in various electro-hydraulic control fields. The precise control of hydraulic motors is usually achieved by using electro-hydraulic servo valves or electro-hydraulic proportional valves as control elements, and by forming electrical negative feedback through angle sensors, controllers and control algorithms. However, electro-hydraulic servo valves or electro-hydraulic proportional valves are expensive and require high maintenance. The parameters of the control algorithm also need to be adjusted. Therefore, although this method can achieve high precision, the price and maintenance costs and the complexity of debugging are high. The stepper hydraulic motor (also known as a digital hydraulic motor) uses mechanical negative feedback to organically combine the motor, single-stage servo valve and hydraulic motor. Its position and speed control method is equivalent to stepper motor control. One pulse corresponds to a certain angle, and the pulse frequency corresponds to the speed. No other control algorithms are required. Although the accuracy is slightly lower, it is easy to use and has high reliability. It has a large application market in occasions where the accuracy requirements are not high. At present, most stepper hydraulic motors use a slide valve structure. The hydraulic force of the slide valve is large. The stepper motor needs a deceleration mechanism to increase the torque to drive. The valve core and valve sleeve have a long matching size, and the matching parts need to be precisely processed. Feedback mechanisms mostly use gear transmission. Since the output of the stepper motor is the rotation angle and the input of the slide valve is the linear displacement, the stepper motor needs a rotation-to-linear conversion mechanism to control the movement of the slide valve. Currently, ball screws are mostly used. The mechanical feedback mechanism of the hydraulic motor to the slide valve mostly uses a gear pair, but the ordinary gear pair has low precision, the high-precision gear pair is expensive, and the driven gear rotates in the opposite direction to the driving gear. Summary of the invention

[0003] In order to overcome the above shortcomings, the present invention designs a dual-valve core rotary valve controlled stepper hydraulic motor, which replaces the sliding valve with a rotary valve with small hydraulic force and simple processing, replaces the gear pair with a synchronous belt, and adds an angle sensor. In addition to real-time monitoring of the operating status of the hydraulic motor, electrical negative feedback can be added according to the requirements of the application to compensate for factors such as load changes, internal leakage and dead zone.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A dual-spool rotary valve controlled stepper hydraulic motor comprises a dual-spool rotary valve, a synchronous belt transmission mechanism, a dual-output shaft hydraulic motor, an angle sensor and an oil pipe. The dual-spool rotary valve comprises a hollow stepper motor, a valve body, a passive valve core and an active valve core. The synchronous belt transmission mechanism comprises a synchronous belt large wheel, a synchronous belt and a synchronous belt small wheel. The hollow stepper motor is connected to the active valve core, the passive valve core is connected to the synchronous belt large wheel, the output shaft at the rear end of the dual-output shaft hydraulic motor is connected to the synchronous belt small wheel, the angle sensor is installed on the synchronous belt small wheel, and the dual-output shaft hydraulic motor forms mechanical negative feedback on the dual-spool rotary valve through the synchronous belt.

[0006] Further optimization is carried out, the active valve core has two bosses, the passive valve core has two rectangular oil ports and two circular oil holes, the boss width is the same as the rectangular oil port width, the active valve core and the passive valve core, the passive valve core and the valve body form a clearance fit, so that the active valve core can rotate in the passive valve core, and the passive valve core can rotate in the valve body. The rotation causes the relative position of the boss and the rectangular oil port to change, forming a variable throttling port.

[0007] Further optimization, the dual-output shaft hydraulic motor drives the small wheel of the synchronous belt to rotate, and drives the large wheel of the synchronous belt to rotate through the synchronous belt transmission. The large wheel of the synchronous belt drives the passive valve core of the rotary valve to rotate to form a mechanical negative feedback, so that the throttle port formed by the passive valve core and the active valve core gradually closes. When the throttle port is completely closed, the hydraulic motor stops rotating.

[0008] Further optimization, the rotation angle of the stepper hydraulic motor under one pulse instruction is equal to the product of the rotation angle of the hollow stepper motor and the transmission ratio of the synchronous belt, and the rotation speed is equal to the product of the frequency of the pulse instruction and the rotation angle.

[0009] Further optimization is carried out in which the front end of the dual-shaft hydraulic motor is connected to an external load, and an angle sensor realizes real-time monitoring of the operating status of the hydraulic motor. It can also increase the control to form electrical negative feedback to compensate for the influence of pressure load, internal leakage, dead zone and other factors on the control accuracy, thereby improving the accuracy of the stepper hydraulic motor.

[0010] The beneficial effects of the present invention are:

[0011] 1. Both the rotary valve and the stepper motor are rotary motions, and there is no need for a transmission mechanism from rotation to linear motion. In addition, the hollow stepper motor is directly connected to the active valve core, and no coupling is required, so the structure is simpler and more compact;

[0012] 2. Compared with the slide valve, the rotary valve has small size, small inertia, small hydraulic force, small precision matching size, strong anti-pollution ability, small impact on the dynamic performance of the stepper motor, low processing cost, which is conducive to improving the performance of the entire stepper hydraulic motor;

[0013] 3. Use synchronous belt as mechanical negative feedback device, with high efficiency, stable transmission and high precision;

[0014] 4. An angle sensor is installed on the output shaft of the hydraulic motor, which can not only monitor the operating status of the stepper hydraulic motor in real time, but also compensate for the influence of load changes, internal leakage and dead zone on control accuracy by adding a controller to form electrical negative feedback, so that it can be used in occasions with higher precision requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the structural principle diagram of the double valve core rotary valve controlled stepper hydraulic motor;

[0016] Figure 2 This is the working principle diagram of the double valve core rotary valve;

[0017] Markings in the figure: 1. Hollow stepper motor, 2. Valve body, 3. Passive valve core, 4. Active valve core, 5. Synchronous belt large wheel, 6. Synchronous belt, 7. Synchronous belt small wheel, 8. Angle sensor, 9. Upper end oil pipe, 10. Lower end oil pipe, 11. Double-output shaft hydraulic motor, 12. Front end output shaft of hydraulic motor, 13. Upper end control oil chamber of hydraulic motor, 14. Lower end control oil chamber of hydraulic motor, 15. Rear end output shaft of hydraulic motor. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention.

[0019] A dual-valve core rotary valve controlled stepper hydraulic motor, characterized in that it includes a rotary valve body, a synchronous belt transmission mechanism, a dual-output shaft hydraulic motor, an angle sensor and an oil pipe. The rotary valve body includes a hollow stepper motor, a valve body, a passive valve core and an active valve core. The synchronous belt transmission mechanism includes a synchronous belt large wheel, a synchronous belt and a synchronous belt small wheel.

[0020] In the present invention, the shaft of the active valve core 4 directly extends into the hollow stepping motor 1, the shaft of the passive valve core 3 is connected to the synchronous belt large wheel 5, the synchronous belt large wheel 5 and the synchronous belt small wheel 7 are connected through a synchronous belt, the synchronous belt small wheel 7 is connected to the rear output shaft 15 of the hydraulic motor, and the angle sensor 8 is also connected to the rear output shaft 15 of the hydraulic motor. The rotary valve control oil port is connected to the upper end control oil chamber 13 of the hydraulic motor and the lower end control oil chamber 14 of the hydraulic motor through the upper end oil pipe 9 and the lower end oil pipe 10 respectively.

[0021] The convex shoulder on the active valve core 4 is in clearance with the hollow part of the passive valve core 3. The surface of the hollow part of the passive valve core 3 is provided with two rectangular oil ports and two circular oil ports, and the two circular oil ports are respectively the oil inlet P of the rotary valve and the oil return T of the rotary valve. The rectangular oil hole of the passive valve core 3 and the convex shoulder of the active valve core 4 constitute a variable throttle port, which controls the rotation of the hydraulic motor 11, the oil inlet P of the rotary valve is connected to the high-pressure oil, and the oil return T of the rotary valve is connected to the oil tank.

[0022] Working principle: counterclockwise rotation is set through the stepper motor driver. When a pulse command is issued to the hollow stepper motor 1, the hollow stepper motor 1 will drive the active valve core 4 to rotate counterclockwise to the corresponding angle, and the variable throttle port composed of the active valve core 4 and the passive valve core 3 will open the corresponding opening. The high-pressure oil will flow into the rotary valve through the oil inlet P of the rotary valve, and flow into the upper control oil chamber 13 of the hydraulic motor through the control oil port A of the rotary valve along the upper oil pipe 9. The low-pressure oil will flow into the rotary valve through the lower control oil chamber 14 of the hydraulic motor through the lower oil pipe 10, through the control oil port B of the rotary valve, and flow back to the oil tank through the return oil port T of the rotary valve. The two control chambers of the hydraulic motor 11 generate a pressure difference, which drives the output shaft of the hydraulic motor 11 to rotate counterclockwise, the front output shaft 12 drives the external load to rotate, and the rear output shaft 15 drives the synchronous belt small wheel 7 to rotate counterclockwise. At the same time, the synchronous belt small wheel 7 drives the synchronous belt large wheel 5 to rotate counterclockwise, and the passive valve core 3 connected to the synchronous belt large wheel 5 also rotates counterclockwise. This rotation will cause the passive valve core 3 and the active valve core 4 to form a variable throttle port closure. When the variable throttle port is completely closed, the hydraulic motor 11 stops rotating.

[0023] The stepper motor driver is set to rotate clockwise. When a pulse command is sent to the hollow stepper motor 1, the active valve core 4 will rotate clockwise to a corresponding angle, and the variable throttle formed by the active valve core 4 and the passive valve core 3 will open to a corresponding degree. The high-pressure oil will flow into the rotary valve through the oil inlet P of the rotary valve, and flow into the lower control oil chamber 14 of the hydraulic motor through the control oil port B of the rotary valve along the lower oil pipe 10. The low-pressure oil will flow into the rotary valve through the upper control oil chamber 13 of the hydraulic motor through the upper oil pipe 9 and the control oil port A of the rotary valve, and flow back to the oil tank through the return oil port T of the rotary valve. At this time, the output shaft of the hydraulic motor 11 will rotate clockwise, and the passive valve core 3 will rotate counterclockwise under the synchronous belt drive. At the same time, the variable throttle formed by the passive valve core 3 and the active valve core 4 will gradually close. When the variable throttle is completely closed, the hydraulic motor 11 stops rotating.

[0024] The ratio of the rotation angle of the hydraulic motor 11 to the rotation angle of the hollow stepper motor 1 is the transmission ratio of the synchronous belt. Since the rotation angle of the hollow stepper motor 1 is proportional to the number of pulse instructions, and the rotation speed is proportional to the frequency of the pulse instructions, the rotation angle of the hydraulic motor 11 is also proportional to the number of pulse instructions, and the rotation speed is proportional to the frequency of the pulse instructions. The rotation angle of the hydraulic motor 11 will be monitored in real time by the angle sensor 8 connected to the rear output shaft 15 of the hydraulic motor.

[0025] When applied to applications with higher precision or where there are load changes, severe internal leakage, dead zones and other interference factors that have a greater impact, the signal of the rotation angle of the hydraulic motor 11 detected by the angle sensor 8 can be transmitted to a controller such as a PLC or a computer through sampling, and through a control algorithm, electrical and mechanical composite negative feedback can be established to achieve interference interference and obtain higher precision control.

[0026] While retaining the advantages of the current stepper hydraulic motor, the stepper hydraulic motor uses a rotary valve to control the angle and speed of the hydraulic motor. Compared with the slide valve, under the same control flow, the rotary valve has smaller hydraulic power, smaller volume, lighter weight, fewer precision machining dimensions, and both the stepper motor and the stepper motor are rotary motion, which can realize direct motor drive without the need for a conversion mechanism from rotary motion to linear motion and a motor reduction mechanism. Therefore, it has the characteristics of low cost, simple structure, and strong anti-pollution ability.

[0027] The stepper hydraulic motor uses a hollow stepper motor to directly drive the rotary valve, which has a more compact structure and uses a synchronous belt as a negative feedback mechanism, which can reduce costs while ensuring accuracy. By adding an angle sensor, the operating status of the hydraulic motor can be monitored in real time, and electrical negative feedback can be added according to the needs of the application to compensate for factors such as load changes, internal leakage, and dead zone. Therefore, it has the characteristics of compact structure, convenient maintenance and application, and can monitor the output status of the stepper hydraulic motor in real time.

[0028] The above shows and describes the main features, methods of use, basic principles and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements according to actual conditions, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A dual-spool rotary valve controlled stepper hydraulic motor, characterized in that: The invention comprises a double-valve core rotary valve, a synchronous belt transmission mechanism, a double-output shaft hydraulic motor (11), an angle sensor (8) and an oil pipe. The double-valve core rotary valve comprises a hollow stepping motor (1), a valve body (2), a passive valve core (3) and an active valve core (4). The synchronous belt transmission mechanism comprises a synchronous belt large wheel (5), a synchronous belt (6) and a synchronous belt small wheel (7). The hollow stepping motor (1) is connected to the active valve core (4), the passive valve core (3) is connected to the synchronous belt large wheel (5), the output shaft at the rear end of the double-output shaft hydraulic motor (11) is connected to the synchronous belt small wheel (7), the angle sensor (8) is mounted on the synchronous belt small wheel (7), and the double-output shaft hydraulic motor (11) forms mechanical negative feedback on the double-valve core rotary valve through the synchronous belt (6).

2. A dual-spool rotary valve controlled stepper hydraulic motor as claimed in claim 1, characterized in that: The active valve core (4) has two convex shoulders, and the passive valve core (3) has two rectangular oil ports and two circular oil holes. The width of the convex shoulders is the same as the width of the rectangular oil ports. The active valve core (4) and the passive valve core (3), as well as the passive valve core (3) and the valve body (2) form a clearance fit, so that the active valve core (4) can rotate inside the passive valve core (3), and the passive valve core (3) can rotate inside the valve body (2). The rotation changes the relative position of the convex shoulders and the rectangular oil ports, thereby forming a variable throttle port.

3. A dual-spool rotary valve controlled stepper hydraulic motor as claimed in claim 1, characterized in that: The dual-output shaft hydraulic motor (11) drives the synchronous belt small wheel (7) to rotate, which in turn drives the synchronous belt large wheel (5) to rotate via the synchronous belt (6). The synchronous belt large wheel (5) drives the passive valve core (3) to rotate, thereby forming a mechanical negative feedback to the dual-valve core rotary valve, so that the throttle port formed by the passive valve core (3) and the active valve core (4) is gradually closed. When the throttle port is completely closed, the dual-output shaft hydraulic motor (11) stops rotating.

4. A dual-spool rotary valve controlled stepper hydraulic motor as claimed in claim 1, characterized in that: The rotation angle of the stepper hydraulic motor under a pulse command is equal to the product of the rotation angle of the hollow stepper motor (1) and the transmission ratio of the synchronous belt (6), and the rotation speed is equal to the product of the frequency of the pulse command and the rotation angle.

5. A dual-spool rotary valve controlled stepper hydraulic motor as claimed in claim 1, characterized in that: The front end of the dual-output shaft hydraulic motor (11) is connected to an external load, and the angle sensor (8) realizes real-time monitoring of the operating state of the dual-output shaft hydraulic motor (11), and can also form a mechanical and electrical composite negative feedback double closed-loop control through an external controller to improve the accuracy of the stepper hydraulic motor.

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