A power failure compensation mechanism for an ultrasonic motor-driven two-dimensional electro-hydraulic servo valve

Abstract

This invention discloses a power-off compensation mechanism for a two-dimensional electro-hydraulic servo valve directly driven by an ultrasonic motor. The mechanism includes a 2D valve assembly, an ultrasonic motor, an electromagnetic transmission assembly connecting the 2D valve assembly and the ultrasonic motor, and a motor cover. The 2D valve assembly includes an LVDT body, an LVDT sensing core, a left valve end cover, a left plug, a valve body, a valve sleeve, a valve core, a concentric ring, and a right plug. The electromagnetic transmission assembly includes a braking assembly and a motion transmission assembly. The braking assembly includes a right valve end cover, a coil, a retaining ring, and a return spring assembly. The motion transmission assembly includes a first coupling, an armature, and a second coupling. This invention uses a direct-drive ultrasonic motor to move the valve core via the motion transmission assembly. Energizing the braking assembly disconnects the valve core shaft from the motor shaft, solving the problem of the ultrasonic motor jamming due to power failure. This allows for independent and effective control of the valve core even during abnormal braking and when the motor stops rotating.

Description

Technical Field

[0001] This invention relates to the technical field of 2D valves, and in particular to the technical field of ultrasonic motor-driven two-dimensional electro-hydraulic servo valves. Background Technology

[0002] Ultrasonic motors utilize the inverse piezoelectric properties of piezoelectric materials to excite the mechanical vibration of the motor stator. Through the friction between the stator and rotor, electrical energy is converted into mechanical energy, driving the directional motion of the rotor. Compared with traditional motors, ultrasonic motors have advantages such as simple structure, small size and light weight, fast response speed, low noise, high torque at low speed, good control characteristics, self-locking upon power failure, immunity to magnetic field interference, and accurate motion. In addition, they also have the characteristics of being resistant to low temperatures and vacuum, making them suitable for space environments.

[0003] Firstly, due to its light weight, low speed, and high torque, it eliminates the need for additional gears or other transmission structures, avoiding a series of problems associated with gear transmissions, such as vibration, impact, noise, low efficiency, and difficulty in control. Secondly, it breaks through the traditional concept of electric motors, eliminating electromagnetic windings and magnetic circuits, and using electromagnetic interaction to convert energy. Instead, it utilizes the inverse piezoelectric effect of piezoelectric ceramics, ultrasonic vibration, and frictional coupling to convert energy. This results in advantages such as quiet operation, low pollution, high positioning accuracy, and immunity to electromagnetic interference. Therefore, using an ultrasonic motor for direct drive as the driving method for two-dimensional electro-hydraulic servo valves has significant advantages.

[0004] However, under abnormal braking conditions, the advantage of the ultrasonic motor's self-locking mechanism after power failure can actually become a disadvantage. The rotor and stator of the ultrasonic motor are always in close contact. After the power is cut off, due to the effect of static friction, there is still a large holding torque even without a braking device. Therefore, turning off the ultrasonic motor will directly restrict the rotation of the valve core, which means that the problem of valve core zero-position drift cannot be solved. Summary of the Invention

[0005] The purpose of this invention is to solve the problems in the prior art and propose a power failure compensation mechanism for a two-dimensional electro-hydraulic servo valve driven by an ultrasonic motor. The valve core is driven by a motion transmission component through a direct ultrasonic motor drive. When the braking component is energized, the connection between the valve core shaft and the motor shaft is disconnected. This enables independent and effective control of the valve core even when there is abnormal braking and the motor stops rotating.

[0006] To achieve the above objectives, the present invention proposes a power failure compensation mechanism for a two-dimensional electro-hydraulic servo valve directly driven by an ultrasonic motor, comprising a 2D valve assembly, an ultrasonic motor, an electromagnetic transmission assembly connecting the 2D valve assembly and the ultrasonic motor, and a motor cover plate.

[0007] The 2D valve assembly includes a valve body, a valve left end cap fixed to the left side of the valve body, a valve sleeve embedded in the valve body, a valve core fitted inside the valve sleeve, a left plug (14) embedded inside the left end of the valve core, an LVDT sensing core passing through the valve left end cap and fitted inside the plug, an LVDT body fitted outside the LVDT sensing core and embedded in the left end of the spool valve left end cap, a right plug embedded inside the left end of the valve core, and a concentric ring fitted on the outer circumference of the right side of the valve core, wherein the outer circumference of the concentric ring is fitted with the inner wall of the valve sleeve.

[0008] The electromagnetic transmission assembly includes a braking assembly and a motion transmission assembly. The braking assembly includes a right valve end cover fixed to the right side of the valve body, a coil nested inside the right valve end cover, a retaining ring covering the right side of the coil, and a set of return springs axially embedded in the right side of the right valve end cover. The motion transmission assembly includes a first coupling fixed to the right end of the valve core on the left, an armature axially sleeved on the right end of the first coupling, and a second coupling fixed to the motor shaft of the ultrasonic motor on the right. The motor cover plate is screwed through the right valve end cover and fitted onto the valve body. The motor shaft of the ultrasonic motor passes through the motor cover plate and connects to the second coupling, and is fixed to the motor cover plate by screws.

[0009] Preferably, the armature has involute gears on its inner and outer circumferential surfaces, an external gear on the right circumferential surface of the first coupling, and an internal gear on the left circumferential surface of the second coupling. The armature is axially sleeved on the right end of the first coupling, with its inner end face meshing with the right end of the first coupling in an involute gear manner, and its outer end face meshing with the left end of the second coupling in an involute gear manner.

[0010] Preferably, the armature has involute gears on its inner and outer circumferential surfaces, the right end of the first coupling has an external gear on its right circumferential surface, and the left end of the second coupling has an internal gear on its left circumferential surface. The armature is axially sleeved on the right end of the first coupling, with its inner end face meshing with the right end of the first coupling in an involute gear manner, and its outer end face meshing with the left end of the second coupling in an involute gear manner. The number of meshing teeth on the second coupling and the armature, and on the armature and the first coupling, are equal.

[0011] Preferably, the right end cover of the valve has six circular through holes evenly distributed around its right end face, and a set of return springs is embedded in each of the circular through holes; the armature abuts against the set of return springs.

[0012] The beneficial effects of this invention are as follows: This invention disconnects the valve core from the motor shaft by energizing the armature with a coil, enabling independent and effective control of the valve core even during abnormal braking and when the motor stops rotating; the valve core is driven by an ultrasonic motor, which is not affected by electromagnetic interference.

[0013] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description

[0014] Figure 1 This is a perspective view of the power failure compensation mechanism of the ultrasonic motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0015] Figure 2 This is a front cross-sectional view of the power failure compensation mechanism of the ultrasonic motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0016] Figure 3 This is an exploded view of the motion transmission component of the power failure compensation mechanism of the ultrasonic motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0017] In the diagram: 1-2D valve assembly, 11-LVDT body, 12-LVDT sensing core, 13-left valve end cover, 14-left plug, 15-valve body, 16-valve sleeve, 17-valve core, 18-concentric ring, 19-right plug, 2-electromagnetic transmission assembly, 201-braking assembly, 202-motion transmission assembly, 21-right valve end cover, 22-coil, 23-retaining ring, 24-first coupling, 25-armature, 26-second coupling, 27-reset spring assembly, 31-motor cover plate, 32-ultrasonic motor. Detailed Implementation

[0018] See Figure 1 , Figure 2 The present invention includes a 2D valve assembly 1, an ultrasonic motor 32, an electromagnetic transmission assembly 2 connecting the 2D valve assembly 1 and the ultrasonic motor 32, and a motor cover plate 31.

[0019] The 2D valve assembly 1 includes a valve body 15, a valve left end cap 13 fixed to the left side of the valve body 15, a valve sleeve 16 embedded inside the valve body 15, a valve core 17 fitted inside the valve sleeve 16, a left plug 14 embedded inside the left end of the valve core 17, an LVDT sensing core 12 passing through the valve left end cap 13 and fitted inside the plug 14, an LVDT body 11 fitted outside the LVDT sensing core 12 and embedded in the left end of the spool valve left end cap 13, a right plug 19 embedded inside the left end of the valve core 17, and a concentric ring 18 fitted on the outer circumferential surface of the right side of the valve core 17. The outer circumference of the concentric ring 18 is fitted with the inner wall of the valve sleeve 16.

[0020] The electromagnetic transmission assembly 2 includes a braking assembly 201 and a motion transmission assembly 202. The braking assembly 201 includes a valve right end cover 21 fixed to the right side of the valve body 15, a coil 22 nested in the valve right end cover 21, a retaining ring 23 covering the right side of the coil, and a set of return springs 27 axially embedded in the right side of the valve right end cover 21. The motion transmission assembly 202 includes a first coupling 24 fixed to the right end of the valve core 17 on the left, an armature 25 axially sleeved on the right end of the first coupling 24, and a second coupling 26 fixed to the motor shaft of the ultrasonic motor 32 on the right. The motor cover plate 31 is screwed through the valve right end cover 21 and fitted onto the valve body 15. The motor shaft of the ultrasonic motor 32 passes through the motor cover plate 31 and is connected to the second coupling 26, and is fixed to the motor cover plate 31 by screws.

[0021] Specifically, the armature has involute gears on its inner and outer circumferential surfaces, the first coupling 24 has an external gear on its right circumferential surface, and the second coupling 26 has an internal gear on its left circumferential surface. The armature is axially sleeved on the right end of the first coupling 24, with its inner end face meshing with the right end of the first coupling 24 in an involute gear manner, and its outer end face meshing with the left end of the second coupling 26 in an involute gear manner.

[0022] Specifically, the armature 25 has involute gears on its inner and outer circumferential surfaces, the first coupling 24 has an external gear on its right circumferential surface, and the second coupling 26 has an internal gear on its left circumferential surface. The armature 25 is axially sleeved on the right end of the first coupling 24, with its inner end face meshing with the right end of the first coupling 24 in an involute gear manner, and its outer end face meshing with the left end of the second coupling 26 in an involute gear manner. The number of meshing teeth on the second coupling 26 and the armature 25, and on the armature 25 and the first coupling 24, is equal. To ensure a certain centering accuracy and installation process, a clearance fit with a minimum clearance of zero can be selected, such as H7 / h6.

[0023] Specifically, the right end cover 21 of the valve has 6 round through holes evenly distributed around its right end face, and a set of return springs 27 is embedded in the round through holes; the armature 25 abuts against the set of return springs 27.

[0024] The working process of this invention:

[0025] The power failure compensation mechanism of the ultrasonic motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention is described in conjunction with the accompanying drawings during its operation.

[0026] The LVDT (Linear Displacement Sensor) is used to measure the axial displacement of the valve core 17 and is fixedly connected to the valve core 17. The left part of this application is a 2D valve (half-bridge) that drives the axial movement of two chambers through rotation. This part is the same as the 2D valve previously applied for by the applicant team. The 2D valve of this application has high and low pressure holes and spiral grooves on the left side, and constant high pressure on the right side. There is also a concentric ring 18 for support on the right side, which means that the area on the left side is A, the area on the right side is 1 / 2 A, and constant high pressure is maintained. The valve body part is prior art. The inventiveness of this invention is that: the rotor and stator of the ultrasonic motor are always in close contact. After the power is cut off, due to the effect of static friction, there is still a large holding torque without the use of a braking device. Therefore, turning off the ultrasonic motor will directly restrict the rotation of the valve core, that is, it cannot solve the problem of zero-position drift of the valve core. However, this invention uses the ultrasonic motor to drive the valve core through the motion transmission component. The braking component is energized to disconnect the connection between the valve core shaft and the motor shaft, solving the problem of the ultrasonic motor getting stuck when the power is off. It can achieve independent and effective control of the valve core in the case of abnormal braking and the motor stopping rotation.

[0027] During normal operation, the braking assembly 201 is not activated, and the armature 25 is in the position specified in the manual transmission protocol. Figure 2 At the indicated position, the armature and the second coupling 26 are in gear engagement. At this time, the ultrasonic motor 32 drives the second coupling 26 to rotate, which in turn drives the valve core 17 to rotate via the armature 25 and the first coupling 24. The first coupling 24 and the armature 25 move freely axially, thus allowing the valve core 17 to function normally. When abnormal braking occurs due to factors such as oil port blockage, the ultrasonic motor 32 is turned off, and the braking assembly 201 operates, energizing the coil 22. The armature 25 receives electromagnetic attraction, causing its left side to press tightly against the right side of the retaining ring 23. The return spring assembly 27 compresses and stores elastic potential energy, thereby disconnecting the armature 25 from the second coupling 26, which is equivalent to disconnecting the valve core 17 shaft from the ultrasonic motor 32 shaft. At this time, the valve core 17 gains rotational freedom, preventing jamming. After the fault is cleared, the coil 22 is de-energized, and the armature 25 loses its electromagnetic attraction. The return spring assembly 27 releases some elastic potential energy to give the armature 25 a restoring force, causing the right side of the armature 25 to press tightly against the left side of the second coupling 26. Then, the ultrasonic motor 32 is turned on. When the second coupling 26 rotates to the appropriate position, the armature 25 and the second coupling 26 can engage. The return spring assembly 27 continues to release the remaining elastic potential energy to give the armature 25 a restoring force, and the armature 25 returns to its original position. Figure 2 The location shown indicates that the device is functioning normally at this point.

[0028] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A power-off compensation mechanism of an ultrasonic motor directly driving a two-dimensional electro-hydraulic servo valve, characterized in that: The application relates to a 2D valve assembly (1), an ultrasonic motor (32), an electromagnetic transmission assembly (2) connecting the 2D valve assembly (1) and the ultrasonic motor (32) and a motor cover plate (31). The 2D valve assembly (1) comprises a valve body (15), a left end cover (13) fixed to the left side of the valve body (15), a valve sleeve (16) embedded in the valve body (15), a valve core (17) matched in the valve sleeve (16), a left plug (14) embedded in the left end of the valve core (17), an LVDT sensing core (12) penetrating through the left end cover (13) and matched in the left plug (14), an LVDT main body (11) sleeved on the outside of the LVDT sensing core (12) and embedded in the left end of the left end cover (13), a right plug (19) embedded in the left end of the valve core (17), and a concentric ring (18) sleeved on the outer circumferential surface of the right part of the valve core (17), wherein the outer circumferential surface of the concentric ring (18) is matched with the inner wall of the valve sleeve (16). The electromagnetic transmission assembly (2) comprises a brake assembly (201) and a motion transmission assembly (202), the brake assembly comprises a right end cover (21) fixed to the right side of the valve body (15), a coil (22) nested in the right end cover (21), a check ring (23) covered on the right side of the coil and a reset spring group (27) axially embedded in the right side of the right end cover (21); the motion transmission assembly comprises a first coupling (24) fixed to the right end of the valve core (17), an armature (25) axially sleeved on the right end of the first coupling (24) and a second coupling (26) fixed to the motor shaft of the ultrasonic motor (32); the motor cover plate (31) is matched on the valve body (15) through a screw penetrating through the right end cover (21); the motor shaft of the ultrasonic motor (32) is connected with the second coupling (26) through the motor cover plate (31) and is fixed to the motor cover plate (31) through a screw; The inner and outer circumferential surfaces of the armature are provided with involute gears, the right end circumferential surface of the first coupling (24) is provided with an external gear, and the left end circumferential surface of the second coupling (26) is provided with an internal gear; the armature (25) is axially sleeved on the right end of the first coupling (24), the inner end surface thereof is engaged with the right end of the first coupling (24) in the form of an involute gear, and the outer end surface thereof is engaged with the left end of the second coupling (26) in the form of an involute gear; the number of engaging teeth on the second coupling (26) and the armature (25) and the first coupling (24) is equal. The inner and outer circumferential surfaces of the armature are provided with involute gears, the right end circumferential surface of the first coupling (24) is provided with an external gear, and the left end circumferential surface of the second coupling (26) is provided with an internal gear; the armature (25) is axially sleeved on the right end of the first coupling (24), the inner end surface thereof is engaged with the right end of the first coupling (24) in the form of an involute gear, and the outer end surface thereof is engaged with the left end of the second coupling (26) in the form of an involute gear; the number of engaging teeth on the second coupling (26) and the armature (25) and the first coupling (24) is equal.

2. The power-fail compensating mechanism of claim 1, wherein: The valve right end cover (21) is internally provided with 6 circular through holes which are uniformly distributed in the right end face and reset spring groups (27) are embedded in the circular through holes; the armature (25) abuts against the reset spring groups (27).

3. The power failure compensation mechanism for a direct-drive two-dimensional electro-hydraulic servo valve using an ultrasonic motor as described in claim 1, characterized in that: The first coupling (24) and the second coupling (26) are respectively clamped on the valve core (17) and the motor shaft of the ultrasonic motor (32) by bolts.

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