Double-nozzle baffle type electric feedback servo valve driven by linear motor

Abstract

The invention discloses a double-nozzle baffle type electric feedback servo valve driven by a linear motor. The servo valve comprises a driving stage, a prestage and a power stage, and the driving stage comprises the linear motor, a connecting rod, an electric connector, a motor seat and an end cover; the prestage comprises a baffle plate, a joint bearing, a nozzle and a primary seat; the power level comprises a valve element, a magnetic head connecting rod, an electric displacement sensor LVDT, a shell, a right end cover, a left end cover and a cover. Linear motion of the linear motor and the connecting rod is converted into deflection of the baffle, deflection of the baffle changes gaps between the nozzle and the left side and the right side of the baffle, spraying gear variable throttling is achieved, generated pressure difference acts on the left end face and the right end face of the valve element to drive the power-level valve element to move, and finally the position of the valve element is detected through the electric displacement sensor. The linear motor is used for replacing a torque motor to drive the double-nozzle baffle, electric feedback is used for replacing mechanical feedback, parts with the extremely high machining precision requirement are omitted, the spring pipe is prevented from being broken, and the machining difficulty and the motor assembling difficulty are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electro-hydraulic servo control, and in particular to a double-nozzle baffle type electric feedback servo valve driven by a linear motor. Background Art

[0002] At present, the double-nozzle baffle electro-hydraulic servo valves seen in the industry are all driven by torque motors, and their working principle is: the armature in the torque motor drives the baffle to deflect under the drive of the electromagnetic torque. The deflection of the baffle causes the left and right nozzles to produce different degrees of throttling and form a pressure difference, thereby driving the valve core movement and controlling the opening and closing of the valve port. The movement of the valve core drives the deflection of the feedback rod, and the valve core displacement is converted into feedback torque through the feedback rod, which is fed back to the armature assembly of the torque motor to form a balance with the electromagnetic force. Among them, the armature assembly adopts a spring tube support structure. The function of the spring tube support enables the armature assembly to return to the center freely when there is no electromagnetic force, thereby realizing the isolation of the oil in the nozzle overflow chamber from the outside and the contact-free friction movement of the baffle, with high resolution accuracy.

[0003] However, in the double nozzle baffle structure, the wall thickness of the spring tube is only 60μm, and the roundness and coaxiality requirements of the inner and outer circles of the thin wall are both less than 2μm, which makes processing difficult. The spring tube is easily broken during processing or use, resulting in failure of the servo valve performance. In addition, the existing servo valve structure often uses a mechanical feedback rod, which has very strict requirements on the stiffness of the feedback rod. During the grinding process of the feedback rod, the taper and the matching accuracy of the ball head and the valve core groove need to be precisely controlled. The processing accuracy requirements are extremely high, and the scrap rate of parts is also high. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a double-nozzle baffle type electric feedback servo valve driven by a linear motor to solve the problems of high processing precision and difficulty of spring tube and feedback rod of existing servo valve parts.

[0005] In order to solve the above problems, the present invention discloses a double-nozzle flapper type electric feedback servo valve driven by a linear motor, wherein the servo valve comprises a drive stage, a pre-stage, and a power stage;

[0006] The drive stage includes a linear motor, a connecting rod, an electrical connector, a motor seat, and an end cover; the pre-stage includes a baffle, a spherical bearing, a nozzle, and a first-stage seat; the power stage includes a valve, a magnetic head connecting rod, an electric displacement sensor LVDT, a housing, a right end cover, a left end cover, and a cover;

[0007] The linear motor is connected to a connecting rod, which is connected to the upper end of a baffle. The baffle deflects around a joint bearing to form a lever with the joint bearing as a fulcrum. The linear motion of the linear motor and the connecting rod is converted into a deflection of the baffle, and the output torque is amplified through the lever principle. There are two nozzles, which are symmetrically distributed on both sides of the baffle and are press-fitted on the lower end of the joint bearing. The valve core is fixed under the nozzle. The deflection of the baffle changes the gap between the nozzle and the left and right sides of the baffle to achieve variable throttling of the spray stop. The generated pressure difference acts on the left and right end surfaces of the valve core to drive the valve core to move. The electric displacement sensor LVDT includes an LVDT sleeve and an LVDT body. The LVDT sleeve is installed on the surface of the left end cover, and the LVDT body is installed outside the LVDT sleeve. The magnetic head connecting rod is located on one end surface of the valve core, and the magnetic head of the magnetic head connecting rod is located at one end of the connecting rod close to the LVDT body. The electric displacement sensor LVDT is used to detect the position of the valve core.

[0008] Preferably, the linear motor, connecting rod, and electrical connector are installed on the motor seat, the baffle, spherical bearing, and nozzle are installed on the primary seat, and the valve core, magnetic head connecting rod, and electric displacement sensor LVDT are installed on the shell; the motor seat, primary seat, and shell are connected in sequence for fixing the structure and the oil circuit.

[0009] Preferably, the electrical connector is used to connect a circuit, and the ratio of the extension and contraction displacement of the linear motor to the control current is linear.

[0010] Preferably, the upper end of the baffle is fixed to the connecting rod by means of internal and external thread screws and a locking nut.

[0011] Preferably, the pre-stage adopts a hydraulic bridge circuit, and its throttling elements include a pair of throttles and a pair of nozzles; the throttles are symmetrically located at both ends of the filter element, and the high-pressure oil enters the throttle after being filtered by the filter element and then flows through the nozzle.

[0012] Preferably, the nozzle outlet is an overflow chamber, and a damping block with a small hole is arranged inside the overflow chamber to adjust the reference pressure of the hydraulic bridge circuit; the small hole diameters of the damping block are different, and the diameters are changed according to working conditions.

[0013] Preferably, a sealing ring and a plug are provided inside the servo valve to achieve isolation or sealing of the oil circuit; and the LVDT sleeve of the electric displacement sensor is used to achieve oil isolation between the LVDT body and the magnetic head.

[0014] Preferably, the end cover, right end cover, left end cover and lid are servo valve housings, which are used to fix the internal parts of the servo valve or to protect the servo valve.

[0015] Preferably, the electric displacement sensor LVDT is connected to the LVDT modem and servo amplifier outside the servo valve in sequence. The electric displacement sensor LVDT modem completes the signal solution of the LVDT and feeds back to the servo amplifier. The servo amplifier outputs a bidirectional current to the servo valve, and realizes closed-loop control of the servo valve through position feedback.

[0016] Preferably, the linear motor replaces the torque motor of the traditional servo valve, and the electric displacement sensor LVDT replaces the feedback rod of the traditional servo valve, thereby eliminating the spring tube and feedback rod structure.

[0017] The beneficial effects achieved by the present invention are as follows:

[0018] (1) A linear motor is used instead of a torque motor to drive the double nozzle baffle, omitting the parts with extremely high processing precision requirements for the spring tube. The processing requirements for the parts are greatly reduced, and the risk of spring tube breakage is avoided;

[0019] (2) A lever structure with a joint bearing is used to convert the linear motion of the linear motor into rotational motion and amplify the output torque, thereby improving the load-carrying capacity of the motor;

[0020] (3) Electrical feedback is used instead of mechanical feedback, and the feedback rod parts are omitted, which greatly reduces the difficulty of motor assembly and parts processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention provides a schematic diagram of the structure and working principle of a double-nozzle baffle type electric feedback servo valve driven by a linear motor.

[0022] Figure 2 The present invention provides a schematic diagram of a pre-stage structure of a double-nozzle baffle type electric feedback servo valve driven by a linear motor.

[0023] The accompanying drawings are marked as follows: 1. linear motor; 2. electrical connector; 3. sealing ring; 4. connecting rod; 5. internal and external thread screws; 6. locking nut; 7. motor seat; 8. sealing ring; 9. end cover; 10. baffle; 11. sealing ring; 12. spherical bearing; 13. primary seat; 14. nozzle; 15. plug; 16. sealing ring; 17. plug; 18. sealing ring; 19. right end cover; 20. sealing ring; 21. housing; 22. valve core; 23. valve sleeve; 24. sealing ring; 25. magnetic head connecting rod; 26. left end cover; 27. electric displacement sensor LVDT sleeve; 28. electric displacement sensor LVDT body; 29. ​​nut; 30. cover; 31. throttle; 32. filter element; 33. sealing ring; 34. plug; 36. plug; 37. damping block; 38. overflow chamber. DETAILED DESCRIPTION

[0024] The embodiments disclosed in the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] like Figure 1 As shown in the schematic diagram of the structure and working principle of a double-nozzle baffle type electric feedback servo valve driven by a linear motor, the present invention discloses a double-nozzle baffle type electric feedback servo valve driven by a linear motor, the servo valve comprises a driving stage, a pre-stage and a power stage, wherein: the driving stage comprises a linear motor 1, a connecting rod 4, an electrical connector 2, a motor seat 7 and an end cover 9; the pre-stage comprises a baffle 10, a spherical bearing 12, a nozzle 14 and a first-stage seat 13; the power stage comprises a valve core 22, a magnetic head connecting rod 25, an electric displacement sensor LVDT, a housing 21, a right end cover 19, a left end cover 26 and a cover 30; the linear motor 1 is connected to the connecting rod 4, the connecting rod 4 is connected to the upper end of the baffle 10, the baffle 10 deflects around the spherical bearing 12 to form a lever with the spherical bearing 12 as the fulcrum; the linear motor 1 and the connecting rod 4 are converted into a linear motion of the baffle 10 deflection, and the output torque amplification is achieved through the lever principle; there are two nozzles 14, which are symmetrically distributed on both sides of the baffle 10 and pressed on the lower end of the spherical bearing 12, and the valve core 22 is fixed under the nozzle 14; the deflection of the baffle 10 changes the gap between the nozzle 14 and the left and right sides of the baffle 10 to achieve variable throttling of the spray stop, and the generated pressure difference acts on the left and right end surfaces of the valve core 22 to drive the valve core 22 to move; the electric displacement sensor LVDT includes an LVDT sleeve 27 and an LVDT body 28, the LVDT sleeve 27 is installed on the surface of the left end cover 26, and the LVDT body 28 is installed outside the LVDT sleeve 27; the magnetic head connecting rod 25 is located on one side end surface of the valve core 22, and the magnetic head of the magnetic head connecting rod 25 is located at one end of the connecting rod close to the electric displacement sensor LVDT body; the electric displacement sensor LVDT is used to detect the position of the valve core 22.

[0026] The linear motor 1, connecting rod 4, and electrical connector 2 are installed on the motor seat 7, the baffle 10, spherical bearing 12, and nozzle 14 are installed on the primary seat 13, and the valve core 22, magnetic head connecting rod 25, and electric displacement sensor LVDT are installed on the housing 21; the motor seat 7, the primary seat 13, and the housing 21 are connected in sequence for fixing the structure and the oil circuit.

[0027] The electrical connector 2 is used to connect the circuit, and the ratio of the extension and contraction displacement of the linear motor 1 to the control current is approximately linear.

[0028] The upper end of the baffle 10 is fixed to the connecting rod 4 by means of internal and external thread screws 5 and locking nuts 6. In order to ensure the convenience of adjusting the zero position of the nozzle baffle, the baffle 10 can rotate around the internal and external thread screws 5 and the locking nuts 6, but the freedom of movement along the connecting rod 4 is limited. In order to avoid over-positioning caused by installation errors, the connecting rod 4 is an elastic flexible rod.

[0029] like Figure 2 As shown in the schematic diagram of the pre-stage structure of a double-nozzle baffle type electric feedback servo valve driven by a linear motor, the pre-stage adopts a hydraulic bridge circuit, and its throttling elements include a pair of throttles 31 and a pair of nozzles 14; the throttles 31 are symmetrically located at both ends of the filter element 32, and the high-pressure oil enters the throttle 31 after being filtered by the filter element 32, and then flows through the nozzle 14; the outlet of the nozzle 14 is an overflow chamber 38, and a damping block 37 with a small hole is arranged inside the overflow chamber 38 for adjusting the reference pressure of the hydraulic bridge circuit; the aperture of the small hole of the damping block 37 is different, and the aperture is changed according to the working conditions.

[0030] The servo valve is provided with a sealing ring and a plug inside to achieve isolation or sealing of the oil circuit; the LVDT sleeve 27 is used to achieve oil isolation between the electric displacement sensor LVDT body 28 and the magnetic head of the magnetic head connecting rod 25.

[0031] The end cover 9, the right end cover 19, the left end cover 26 and the cover 30 are the outer shells of the servo valve, which are used to fix the internal parts of the servo valve or to protect the servo valve.

[0032] The electric displacement sensor LVDT is connected to the LVDT modem and servo amplifier outside the servo valve in sequence. The electric displacement sensor LVDT modem completes the signal solution of the LVDT and feeds back to the servo amplifier. The servo amplifier outputs a bidirectional current to the servo valve, and realizes closed-loop control of the servo valve through position feedback.

[0033] The linear motor 1 replaces the torque motor of the traditional servo valve, and the electric displacement sensor LVDT replaces the feedback rod of the traditional servo valve, thereby eliminating the spring tube and feedback rod structure.

[0034] The contents not described in detail in this specification belong to the prior art known to those skilled in the art. It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A double-nozzle flapper type electric feedback servo valve driven by a linear motor, characterized in that: The servo valve comprises a drive stage, a pre-stage, and a power stage, wherein: The driving stage comprises a linear motor (1), a connecting rod (4), an electrical connector (2), a motor seat (7), and an end cover (9); The front stage comprises a baffle (10), a joint bearing (12), a nozzle (14), and a first stage seat (13); The power stage comprises a valve core (22), a magnetic head connecting rod (25), an electric displacement sensor LVDT, a housing (21), a right end cover (19), a left end cover (26), and a cover (30); The linear motor (1) is connected to a connecting rod (4), the connecting rod (4) is connected to an upper end of a baffle (10), and the baffle (10) deflects around a joint bearing (12) to form a lever with the joint bearing (12) as a fulcrum; The linear motion of the linear motor (1) and the connecting rod (4) is converted into the deflection of the baffle (10), and the output torque is amplified through the lever principle; There are two nozzles (14), which are symmetrically distributed on both sides of the baffle (10) and are pressed on the lower end of the joint bearing (12). The valve core (22) is fixed below the nozzle (14); The baffle (10) deflects to change the gap between the nozzle (14) and the left and right sides of the baffle (10), thereby realizing variable throttling of the spray stop, and the generated pressure difference acts on the left and right end surfaces of the valve core (22), driving the valve core (22) to move; The electric displacement sensor LVDT comprises an LVDT sleeve (27) and an LVDT body (28), wherein the LVDT sleeve (27) is mounted on the surface of the left end cover (26), and the LVDT body (28) is mounted outside the LVDT sleeve (27); The magnetic head connecting rod (25) is located on one end surface of the valve core (22), and the magnetic head of the magnetic head connecting rod (25) is located at one end of the connecting rod close to the body of the electric displacement sensor LVDT; The electric displacement sensor LVDT is used to detect the position of the valve core (22).

2. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The linear motor (1), the connecting rod (4), and the electrical connector (2) are installed on the motor seat (7); the baffle (10), the spherical bearing (12), and the nozzle (14) are installed on the primary seat (13); the valve core (22), the magnetic head connecting rod (25), and the electric displacement sensor LVDT are installed on the housing (21); the motor seat (7), the primary seat (13), and the housing (21) are connected in sequence for fixing the structure and the oil circuit.

3. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The electrical connector (2) is used to connect the circuit, and the ratio of the extension and contraction displacement of the linear motor (1) to the control current is linear.

4. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The upper end of the baffle (10) is fixed to the connecting rod (4) via internal and external thread screws (5) and a locking nut (6).

5. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The pre-stage adopts a hydraulic bridge circuit, and its throttling elements include a pair of throttles (31) and a pair of nozzles (14); the throttles (31) are symmetrically located at both ends of the filter element (32); the high-pressure oil enters the throttle (31) after being filtered by the filter element (32), and then flows through the nozzle (14).

6. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The outlet of the nozzle (14) is an overflow chamber (38), and a damping block (37) with a small hole is arranged inside the overflow chamber (38) for adjusting the reference pressure of the hydraulic bridge circuit; the small hole of the damping block (37) has different apertures, and the aperture is changed according to working conditions.

7. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: A sealing ring and a plug are arranged inside the servo valve to isolate or seal the oil circuit; the electric displacement sensor LVDT sleeve (27) is used to isolate the oil between the LVDT body (28) and the magnetic head of the magnetic head connecting rod (25).

8. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The end cover (9), the right end cover (19), the left end cover (26) and the cover (30) are the outer shells of the servo valve and are used to fix the internal parts of the servo valve or to protect the servo valve.

9. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The electric displacement sensor LVDT is connected to the LVDT modem and servo amplifier outside the servo valve in sequence. The electric displacement sensor LVDT modem completes the signal solution of the LVDT and feeds back to the servo amplifier. The servo amplifier outputs a bidirectional current to the servo valve, and realizes closed-loop control of the servo valve through position feedback.

10. A double-nozzle flapper type electric feedback servo valve driven by a linear motor according to claim 1, characterized in that: The linear motor (1) replaces the torque motor of a traditional servo valve, and the electric displacement sensor LVDT replaces the feedback rod of a traditional servo valve, thereby eliminating the need for a spring tube and a feedback rod structure.

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