Large flow pneumatic piezoelectric valve based on bridge amplification mechanism

Abstract

The application discloses a large-flow pneumatic piezoelectric valve based on a bridge type amplification mechanism, which comprises a piezoelectric valve structure and a piezoelectric driver, wherein the piezoelectric valve structure comprises a main valve body, a conical valve core, a fixed support, an expansion sleeve, a light shaft and an elastic return plate; the elastic return plate and the fixed support are respectively fixedly installed on the two side end faces of the main valve body, the light shaft is fixedly arranged in the fixed support, and the outside of the light shaft is sleeved with the expansion sleeve; one end of the conical valve core is connected with the piezoelectric driver, and the other end is fixedly connected with the center of the elastic return plate; the piezoelectric driver comprises a bridge type displacement amplification mechanism and a piezoelectric stack, one end of the displacement amplification mechanism is fixedly connected with the conical valve core, and the other end is fixedly connected with the light shaft; the piezoelectric driver part adopts the displacement amplification mechanism, which makes up for the shortage of small output displacement of the piezoelectric stack, the semi-bridge type amplification mechanism reduces the inertial movement of the piezoelectric stack, can effectively enhance the dynamic response efficiency, and has the advantages of fast reset speed of the valve core, adjustable pre-tightening force and good applicability.

Description

Technical Field

[0001] This invention relates to the field of fluid transmission and control, and in particular to a high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism. Background Technology

[0002] Pneumatic piezoelectric valves offer advantages such as simple structure, small size, light weight, tight and reliable operation, good sealing, convenient maintenance and installation, low flow resistance, and strong adaptability, making them widely used in various industrial automatic control systems. Traditional direct-drive servo valves, driven by torque motors or electromagnetic motors, offer the advantage of simple construction but suffer from poor response speed and high weight and size due to the use of large motors to drive the valve core. With the development of piezoelectric materials, servo valves using piezoelectric actuators as new driving elements offer higher control precision, faster response speed, and a more compact structure compared to linear force motors. They also boast advantages such as fast dynamic response and light weight, showing broad application prospects in aerospace, automotive, microelectromechanical engineering, and biomedical fields.

[0003] Piezoelectric stacks offer advantages such as fast frequency response and high output force as drivers; however, their biggest drawback is their small output displacement (typically 0.15% of their own length). To balance output displacement (i.e., flow rate) and dynamic bandwidth within a relatively compact structure, an amplification mechanism is needed to amplify the output displacement of the piezoelectric stack, thereby achieving a high flow rate. Currently, several common flexible hinge-type amplification mechanisms include lever amplification, delta amplification, and bridge amplification. Lever amplification has a simple structure, but its size is relatively large when the amplification factor is high. Delta amplification can theoretically achieve a very high amplification ratio, but its space utilization is not high. Bridge amplification mechanisms have a symmetrical, stable, and compact structure, making them more widely used.

[0004] However, in existing piezoelectric valves, it is difficult to achieve both high dynamic bandwidth and displacement amplification efficiency in a more compact structure. In addition, the structure is mostly an integrated design. Although the overall structure is stable, the components have a single purpose, are inconvenient to process and replace key components, have limited compatibility, and are limited in application scenarios. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of existing valves, such as insufficient flow performance, small valve core displacement, and weak structural versatility that makes replacement inconvenient. The present invention provides a high-flow pneumatic piezoelectric valve based on a bridge amplification mechanism, which improves the dynamic bandwidth of the piezoelectric actuator in a compact structure, realizes high-precision and high-flow control of the valve, and makes component replacement simple and convenient. The overall structure is simple and easy to use.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A high-flow pneumatic piezoelectric valve based on a bridge amplification mechanism includes a piezoelectric valve structure and a piezoelectric actuator. The piezoelectric valve structure includes a main valve body, a conical valve core, a fixed bracket, a shrink sleeve, an optical axis, and an elastic return plate. The piezoelectric actuator consists of a displacement amplification mechanism and a piezoelectric stack.

[0008] The main valve body has a stepped hole at its center. The side of the main valve body has an inlet P and an outlet T that communicate with the stepped hole. The inlet P and outlet T are located on different diameter sections of the stepped hole. A rubber sealing gasket is provided on the stepped surface of the stepped hole.

[0009] The elastic recovery plate and the fixed bracket are located at both ends of the stepped hole and are fixedly installed on both sides of the main valve body. The optical axis is fixedly installed in the end of the fixed bracket away from the main valve body. An expansion sleeve is sleeved on the outside of the optical axis and the expansion sleeve is fixedly installed in the fixed bracket.

[0010] The conical valve core is a stepped column structure adapted to the stepped hole and is movably installed in the stepped hole. The stepped surface of the stepped column contacts or separates from the rubber sealing gasket. An annular groove is provided in the middle of the stepped column. One end of the conical valve core is fixedly connected to the center of the elastic recovery plate.

[0011] The fixed bracket is a hollow frame structure. The piezoelectric actuator includes a displacement amplification mechanism disposed in the fixed bracket and a piezoelectric stack fixedly connected in the displacement amplification mechanism. One end of the displacement amplification mechanism is fixedly connected to one end of the conical valve core located in the fixed bracket through a hexagonal stud, and the other end of the displacement amplification mechanism is fixedly connected to one end of the optical axis located in the fixed bracket.

[0012] Through the elastic deformation of the displacement amplification mechanism, the displacement output by the piezoelectric stack and applied to the input end is amplified and converted into the displacement output end of the displacement amplification mechanism, thereby driving the axial movement of the conical valve core. The stepped surface of the conical valve core separates from the rubber sealing gasket, and the inlet P and outlet T of the main valve body are connected through the annular groove in the middle of the conical valve core.

[0013] Furthermore, an O-ring is embedded on the outer side of the stepped column of the conical valve core, and the O-ring is slidably sealed to the inner wall of the stepped hole of the main valve body.

[0014] Furthermore, threaded posts are provided on both ends of the stepped column of the conical valve core, and the threaded posts on both sides have the same structure.

[0015] Furthermore, the mounting positions of the fixed bracket and the elastic recovery plate on the two end faces of the main valve body can be interchanged.

[0016] Furthermore, the conical valve core is a one-piece molded structure, and the stepped surface edge of its stepped column is provided with an annular protrusion. The outer side of the annular protrusion is provided with an outer conical surface and the inner side is provided with an inner conical surface. The generatrix of the inner conical surface and the axis of the conical valve core make an angle of 45° to 90°.

[0017] Furthermore, the elastic recovery plate is a sheet-like elastomer composed of several layers of annular supports and several small supports connected between adjacent layers of annular supports. The edge of the elastic recovery plate is fixed to the end face of the main valve body, and the center of the elastic recovery plate is connected to the end of the conical valve core through a nut.

[0018] Furthermore, the displacement amplification mechanism is a half-bridge amplification mechanism or a two-stage bridge amplification mechanism.

[0019] Furthermore, the half-bridge amplification mechanism includes a strip-shaped base, lever arms located on both sides of the base, an output end located between the other ends of the two lever arms, and an input end located inside the lever arms. One end of the lever arm is connected to the base via a flexible hinge. The two ends of the output end are respectively connected to the other ends of the two lever arms via flexible arms. The two input ends are respectively connected to the lever arms on both sides via flexible hinges, and the input ends are located in the middle of the lever arms near the base.

[0020] Furthermore, the two-stage bridge amplification mechanism includes a first-stage amplification mechanism and a second-stage amplification mechanism located outside the first-stage amplification mechanism. The piezoelectric stack is fixedly connected to the displacement input end of the first-stage amplification mechanism, and the displacement output end of the first-stage amplification mechanism is fixedly connected to the displacement input end of the second-stage amplification mechanism.

[0021] Furthermore, the piezoelectric stack is a layered piezoelectric ceramic structure and is polarized along the stacking direction. The two ends of the piezoelectric stack are respectively fixedly glued to the inner walls of the two input ends of the displacement amplification mechanism.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The piezoelectric drive section of this invention adopts a bridge-type two-stage amplification mechanism, which compensates for the small output displacement of the piezoelectric stack. Simultaneously, the elastic recovery plate increases the valve core's reset speed. The half-bridge amplification mechanism has one end fixed and the other end deformable for output, avoiding the inertial movement of the piezoelectric stack in traditional bridge-type amplification mechanisms and effectively enhancing dynamic response.

[0024] 2. This invention adopts a modular and detachable structural design, which simplifies the design and facilitates processing. Different displacement amplification mechanisms, such as bridge or reverse bridge amplification mechanisms, can be installed in the fixed bracket, which can change the output direction of the piezoelectric actuator. It can also be flexibly applied by changing the installation position of each part, increasing the applicability of the valve.

[0025] 3. The present invention uses an adjustable optical axis and an expansion sleeve on its outer side to fix the fixed end of the piezoelectric actuator. By adjusting the installation position between the end of the conical valve core and the elastic recovery plate, the initial position and preload of the valve core can be easily adjusted. The force is easy to apply, the structure is stable, and the valve output stability is improved.

[0026] 4. In this invention, a rubber sealing gasket is fixedly installed at the throttling valve port of the main valve body, and a pointed cone-shaped annular protrusion is correspondingly provided on the stepped surface of the conical valve core, so that the contact surface between the conical valve core and the main valve body is annular, which can effectively increase the sealing contact area, reduce the processing requirements of the key mating surfaces of the valve body, and ensure the valve sealing performance. Attached Figure Description

[0027] Figure 1 This is an exploded view of the piezoelectric valve according to Embodiment 1 of the present invention;

[0028] Figure 2 This is a schematic cross-sectional view of the piezoelectric valve in Embodiment 1 of the present invention;

[0029] Figure 3 This is a schematic diagram of the piezoelectric valve bridge amplification mechanism of Embodiment 1 of the present invention;

[0030] Figure 4 This is a side view of the piezoelectric valve according to Embodiment 1 of the present invention;

[0031] Figure 5 This is a schematic diagram of the cross-sectional structure of the conical valve core of the piezoelectric valve in Embodiment 1 of the present invention;

[0032] Figure 6 yes Figure 5 Enlarged view of part A in the middle;

[0033] Figure 7 A schematic diagram of the piezoelectric valve structure in Embodiment 2 of the invention;

[0034] Figure 8 A schematic diagram of the two-stage bridge amplification mechanism in Embodiment 2 of the present invention.

[0035] In the diagram: 1. Conical valve core; 1.1. Annular protrusion; 1.2. Outer conical surface; 1.3. Inner conical surface; 2. Main valve body; 3. Fixed bracket; 4. Half-bridge amplification mechanism; 4.11. Input end; 4.12. Output end; 4.13. Base; 4.14. Lever arm; 4.15. Flexible arm; 4.16. Flexible hinge; 4.2. Second-stage bridge amplification mechanism; 4.21. First-stage amplification mechanism; 4.22. Second-stage amplification mechanism; 5. Piezoelectric stack; 6. Optical axis; 7. Expansion sleeve; 8. Hexagonal stud; 9. O-ring seal; 10. Rubber gasket; 11. Elastic recovery plate; 12. Fixing nut; 13. Fixing bolt. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0037] Please see Figure 1 and Figure 2 A high-flow pneumatic piezoelectric valve based on a bridge amplification mechanism is disclosed, comprising a piezoelectric valve structure and a piezoelectric actuator. The piezoelectric valve structure includes a main valve body 2, a conical valve core 1, a fixed bracket 3, a tightening sleeve 7, an optical axis 6, and an elastic recovery plate 11. The piezoelectric actuator includes a displacement amplification mechanism disposed within the fixed bracket 3 and a piezoelectric stack 5 fixedly connected within the displacement amplification mechanism. Through the elastic deformation of the displacement amplification mechanism, the minute displacement of the piezoelectric stack 5 is amplified and output to the output end of the displacement amplification mechanism, thereby driving the axial movement of the conical valve core 1. The stepped surface of the conical valve core 1 separates from the rubber sealing gasket 10. The inlet P and outlet T of the main valve body 2 are connected through the annular groove in the middle of the conical valve core 1, so that the piezoelectric valve is in the conducting state. At the same time, the elastic recovery plate in the compressed state provides the restoring force when the conical valve core 1 moves in the opposite direction. The position of the optical axis 6 can be easily adjusted by using the tightening sleeve 7, thereby adjusting the initial preload of the conical valve core 1. The design of the conical valve core 1 and the sealing surface effectively reduces the leakage under precise flow control of the valve. With its modular and detachable structural design, this piezoelectric valve is also compatible with various bridge amplification mechanisms, increasing the valve's applicability.

[0038] Example 1:

[0039] like Figure 1 and Figure 2 As shown, the main valve body 2 is a square cylindrical structure. A stepped hole is provided at the center of the main valve body 2. For ease of description, the two sections of the stepped hole will be referred to as the large-diameter hole and the small-diameter hole, respectively. An inlet P and an outlet T communicating with the stepped hole are respectively opened on the sides (preferably two opposite sides) of the main valve body 2, and the inlet P and outlet T are located on different diameter sections of the stepped hole (e.g.,...). Figure 2As shown, the inlet P communicates with the large-diameter hole, and the outlet T communicates with the small-diameter hole. The conical valve core 1 is a stepped column structure adapted to the stepped hole and is movably installed within the stepped hole. For ease of description, the various sections of the stepped column are referred to as the small-diameter section, the medium-diameter section, and the large-diameter section, with the shaft diameters of the small-diameter section, the medium-diameter section, and the large-diameter section increasing sequentially. The small-diameter section of the stepped column is movably inserted into the small-diameter hole, and the large-diameter section is movably inserted into the large-diameter hole. Both the inlet P and the outlet T are located in the area between the small-diameter section and the large-diameter section. Preferably, grooves are provided on the outer circular surfaces of both the large-diameter section and the small-diameter section of the stepped column of the conical valve core 1. O-ring seals 9 are embedded in these grooves, and the O-ring seals 9 are slidably sealed to the inner wall of the stepped hole of the main valve body 2 to ensure the sealing between the conical valve core 1 and the main valve body 2 and prevent fluid leakage.

[0040] An annular groove is provided in the middle of the stepped column (between the small diameter section and the medium diameter section). The annular groove is located between the inlet P and the outlet T. In the initial closed state of the piezoelectric valve, the medium diameter section is opposite to the inlet P, and the annular groove is opposite to the outlet T. Due to the contact between the end face of the medium diameter section and the stepped surface of the stepped hole, the inlet P and the outlet T are in an open state. When the conical valve core 1 is pushed by the displacement amplification mechanism to the... Figure 2 Moving the viewpoint to the right separates the end face of the intermediate diameter section from the stepped surface of the stepped hole, connecting the annular groove with the outer space of the intermediate diameter section, thus putting the inlet P and outlet T in a conductive state. The displacement of the conical valve core 1 determines the distance between the end face of the intermediate diameter section and the stepped surface of the stepped hole, which in turn determines the volume of the conductive area between the inlet P and the outlet T, thereby enabling the adjustment of the valve flow rate.

[0041] To ensure a tight seal between the intermediate diameter end face of the conical valve core 1 and the stepped surface of the stepped hole, and to reliably control the connection and disconnection between the inlet P and the outlet T, a rubber sealing gasket 10 is provided on the stepped surface of the stepped hole (i.e., the interface between the large-diameter hole and the small-diameter hole, i.e., the throttle valve port of the main valve body). The stepped surface of the stepped column (i.e., the intermediate diameter end face of the conical valve core 1) contacts or separates from the rubber sealing gasket 10. Furthermore, as... Figure 5 and Figure 6As shown, the conical valve core 1 is a one-piece molded structure. An annular protrusion 1.1 is provided on the edge of the stepped surface of its stepped column. An outer conical surface 1.2 is provided on the outer side of the annular protrusion 1.1, and an inner conical surface 1.3 is provided on the inner side. The generatrix of the inner conical surface 1.3 forms an angle of 45° to 90° with the axis of the conical valve core 1. When the annular protrusion 1.1 abuts against the side of the rubber sealing gasket 10, the rubber sealing gasket 10 deforms, allowing the outer conical surface 1.2 and the inner conical surface 1.3 to simultaneously contact the side of the rubber sealing gasket 10, thereby effectively increasing the contact area and ensuring the valve's sealing performance. The rubber sealing gasket 10 is softer than the metal conical valve core 1, which can reduce valve core wear under high-frequency operation of the piezoelectric actuator, increasing reliability.

[0042] The elastic recovery plate 11 and the fixed bracket 3 are located at both ends of the stepped hole and are fixedly installed on both end faces of the main valve body 2. Figure 1 and Figure 2 As shown, the elastic recovery plate 11 is a sheet-like elastomer composed of several layers of annular supports and several small supports connecting adjacent layers of annular supports. Its stiffness matches that of the piezoelectric actuator. The elastic recovery plate 11 is generally square, with its four corner edges fixedly connected to the end face of the main valve body 2 by fixing bolts 13, and a bolt through hole is provided in its center. Figure 2 and Figure 4 As shown, threaded posts are provided on both ends of the stepped column of the conical valve core 1. The threaded post at the outer end passes through the bolt hole of the elastic recovery plate 11, and the center of the elastic recovery plate 11 is connected to the end of the conical valve core 1 through the fixing nut 12 threadedly connected to it. When the valve is in the closed state, the distance between the elastic recovery plate 11 and the end of the conical valve core 1 is adjusted by adjusting the position of the fixing nut 12 on the threaded post. This provides a certain preload force for the fit between the middle diameter end face of the conical valve core 1 and the stepped surface of the stepped hole through the deformation of the elastic recovery plate 11. At the same time, after the piezoelectric stack 5 in the piezoelectric actuator is de-energized, the piezoelectric actuator quickly returns to its original state, causing the conical valve core 1 to move to the left and the piezoelectric valve to return to the open state. The elastic recovery force of the elastic recovery plate 11 itself also provides a restoring force for the reset of the conical valve core 1, improving the response speed when the valve is closed.

[0043] Preferably, the threaded column structures at both ends of the conical valve core 1 are identical, meaning the thread diameter, pitch, and helical direction are exactly the same, allowing the elastic recovery plate 11 and both ends of the conical valve core 1 to achieve the same threaded connection. Simultaneously, the threaded holes on both end faces of the main valve body 2 are correspondingly positioned and have the same specifications, allowing the mounting positions of the fixed bracket 3 and the elastic recovery plate 11 on both end faces of the main valve body 2 to be interchanged to accommodate the assembly needs of piezoelectric valves with different structural types.

[0044] like Figure 1 As shown, the fixed bracket 3 is a hollow frame structure with through holes on its upper and lower side walls and openings on all four side walls. Figure 2 As shown, the optical axis 6 is fixedly installed in the end of the fixed bracket 3 away from the main valve body 2. Specifically, the optical axis 6 is located in the through hole on the top side of the fixed bracket 3, and an expansion sleeve 7 is fitted on the outer side of the optical axis 6, which is fixedly installed in the fixed bracket 3. The expansion sleeve 7 is a standard part, and its specifications are selected according to the outer diameter of the optical axis 6 and the load requirements. When installing and using the expansion sleeve 7, first install the other valve components in their positions, fix the lower vertical end of the valve, and connect the optical axis 6 through the expansion sleeve 7 to the end of the piezoelectric actuator. During assembly, a certain initial pressure is applied to the optical axis 6 through the equipment pressure gauge (not shown) and the fixing bolt 13 is tightened. The pressure and friction generated between the containing surfaces of the expansion sleeve 7 cause the outer surface of the expansion sleeve 7 to fit tightly against the inner wall of the through hole of the fixed bracket 3 through friction, while the inner surface of the expansion sleeve 7 presses in the opposite direction to tightly clamp the optical axis 6, thus fixing the optical axis 6 in the fixed bracket 3. The initial preload applied by the optical axis 6 to the piezoelectric actuator can provide a certain preload to the conical valve core 1 through the transmission of the piezoelectric actuator. This preload, combined with the initial deformation of the elastic recovery plate 11, further ensures the sealing performance between the end face of the middle diameter section of the conical valve core 1 and the stepped surface of the stepped hole.

[0045] In this embodiment, the displacement amplification mechanism adopts the following... Figures 1 to 3 The half-bridge amplification mechanism 4 is shown. The half-bridge amplification mechanism 4 is an integrated structure, consisting of a lever-type and a half-bridge amplification section combined to form a two-stage amplification structure. Specifically, as shown... Figure 3 As shown, the half-bridge amplification mechanism 4 is an approximately square frame-like plate structure, including a strip-shaped base 4.13, lever arms 4.14 located on both sides of the base 4.13, an output end 4.12 located between the other ends of the two lever arms 4.14, and an input end 4.11 located inside the lever arms 4.14. One end of the lever arm 4.14 (e.g., Figure 3 The bottom end shown is connected to the base 4.13 via a flexible hinge 4.16, and two lever arms 4.14 are symmetrically arranged on both sides of the base 4.13. The two ends of the output end 4.12 are respectively connected to the other ends of the two lever arms 4.14 via flexible arms 4.15 (as shown). Figure 3 As shown at the top), two input ends 4.11 are respectively connected to the two lever arms 4.14 via flexible hinges 4.16, and are symmetrically arranged on the inner side of the two lever arms 4.14, with the input ends 4.11 located in the middle of the lever arms 4.14 near the base 4.13. The opposite sides of the two input ends 4.11 (i.e., the sides away from the lever arms 4.14) are respectively connected to the two power output ends of the piezoelectric stack 5. The piezoelectric stack 5 can be extended or retracted in the half-bridge amplification mechanism 4 (e.g., ...). Figure 3(as shown in the lateral direction), in the output direction of the half-bridge amplifier 4 (such as...) Figure 3 The longitudinal direction shown is almost motionless, thus avoiding the adverse effects of the inertial motion of the piezoelectric stack in traditional bridge amplifier mechanisms on the overall response frequency.

[0046] Both the base 4.13 and the output end 4.12 are provided with threaded holes. The optical axis 6 is provided with a stud that matches the threaded hole of the base 4.13 on one end face inside the fixed bracket 3. The threaded engagement of the stud with the threaded hole achieves a fixed connection of one end of the half-bridge amplifier mechanism 4. The other short shaft end (output end 4.12) of the half-bridge amplifier mechanism 4 is threaded with a hexagonal stud 8. The end face of the hexagonal stud 8 away from the half-bridge amplifier mechanism 4 is provided with a threaded hole that matches the axial thread of the conical valve core 1. The end of the conical valve core 1 located inside the fixed bracket 3 achieves a fixed connection between the conical valve core 1 and the half-bridge amplifier mechanism 4 through the threaded engagement of the stud with the threaded hole.

[0047] The piezoelectric stack 5 is a multilayered piezoelectric ceramic structure, polarized along the stacking direction. The side of the piezoelectric stack 5 is connected to an AC power supply with a bias voltage via electrode leads to power the piezoelectric stack 5. The two ends of the piezoelectric stack 5 are fixedly connected to the inner walls of the two input terminals of the half-bridge amplifier mechanism 4 by a combination of pre-tightening and adhesive bonding to ensure tight contact between the two. When the piezoelectric stack 5 is energized, it extends, and the input end 4.11 moves relatively away from the base 4.13 due to the action of the piezoelectric stack 5. Since the base 4.13 is fixed by the optical axis 6, the two lever arms 4.14 swing outwards to both sides, thereby driving the two flexible arms 4.15 to move longitudinally away from the base 4.13. The lateral displacement of the input end 4.11 is transmitted through the lever arms 4.14 and flexible arms 4.15, manifesting as a longitudinal displacement away from the base 4.13 at the output end 4.12. Because the input end 4.11 is located in the lower half of the lever arm 4.14, the longitudinal displacement amplitude of the output end 4.12 is much greater than the lateral displacement amplitude of the input end 4.11. Therefore, the output end 4.12 will push the conical valve core 1 towards the base 4.13. Figure 2 The movement to the right, as shown, connects the inlet P to the outlet T. Simultaneously, the elastic recovery plate 11 is stretched and deformed to store energy. Due to the different positions of the input and output action points on the lever arm 4.14 of the half-bridge amplification mechanism 4, and the half-bridge structure formed by the lever arm 4.14 and the flexible arm 4.15, a small stretch along the long axis of the half-bridge amplification mechanism 4 can cause a large contraction along its short axis, thus enabling the half-bridge amplification mechanism 4 to perform displacement amplification.

[0048] The working process of the piezoelectric valve in this embodiment is as follows:

[0049] In such Figure 2Under normal operating conditions, due to the inverse piezoelectric effect of the piezoelectric ceramic material, the piezoelectric stack 5 is energized and elongates along the stacking direction, causing the displacement of the input end of the half-bridge amplification mechanism 4 to be amplified by the lever and the half-bridge structure. In addition, the optical axis 6 connected to the base 4.13 of the half-bridge amplification mechanism 4 is fixed by the expansion sleeve 7. Therefore, the output end 4.12 of the half-bridge amplification mechanism 4 drives the conical valve core 1 to move to the right. At the same time, the elastic recovery plate 11 is stretched and deformed, and the annular protrusion 1.1 of the conical valve core 1 separates from the rubber sealing gasket 10. At this time, the inlet P and outlet T on the main valve body 2 are connected, and the valve is opened.

[0050] When the piezoelectric stack 5 loses power, it quickly recovers, and the elastic recovery plate 11 also contracts synchronously, jointly driving the conical valve core 1 to move to the left. This causes the annular protrusion 1.1 of the conical valve core 1 to re-seal and contact the rubber sealing gasket 10. At this time, the inlet P and outlet T on the main valve body 2 are disconnected, and the valve is closed. Because the piezoelectric stack 5 has a certain restoring force when it loses power, and the half-bridge amplification mechanism 4 and the elastic recovery plate 11 act as elastic bodies, the self-restoring forces of each structure together provide the restoring force for the resetting of the conical valve core 1, improving the response speed when the valve is closed.

[0051] Example 2:

[0052] Please see Figure 7 Thanks to the advantages of this invention, such as the ability to easily change the valve body structure sequence and the detachable displacement amplification mechanism, the traditional bridge amplification mechanism can also be applied to this valve body. Example 2 differs from Example 1 in that the displacement amplification mechanism uses a two-stage bridge amplification mechanism 4.2 to amplify the displacement output of the piezoelectric stack 5.1. For example... Figure 8 As shown, the two-stage bridge amplification mechanism 4.2 includes a first-stage amplification mechanism 4.21 and a second-stage amplification mechanism 4.22 located outside the first-stage amplification mechanism 4.21. The piezoelectric stack 5 is fixedly connected to the displacement input end of the first-stage amplification mechanism 4.21, and the displacement output end of the first-stage amplification mechanism 4.21 is fixedly connected to the displacement input end of the second-stage amplification mechanism 4.22 by bolts.

[0053] Because the displacement amplification mechanism adopts a two-stage series structure, the theoretical displacement amplification factor is the product of the amplification factors of the two stages. Compared with the half-bridge amplification mechanism 4 in Embodiment 1, the two-stage bridge amplification mechanism 4.2 has a larger output displacement and can control a larger valve flow rate, even with a smaller piezoelectric stack 5. Using the two-stage bridge amplification mechanism 4.2, the lateral edge of the piezoelectric actuator does not extend beyond the main valve body 2, making full use of the internal space of the fixed bracket 3 and helping to reduce the overall size of the valve structure.

[0054] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism, characterized in that: It includes a piezoelectric valve structure and a piezoelectric actuator. The piezoelectric valve structure includes a main valve body (2), a conical valve core (1), a fixed bracket (3), a shrink sleeve (7), an optical axis (6), and an elastic recovery plate (11). The main valve body (2) has a stepped hole at its center. The side of the main valve body (2) has an inlet P and an outlet T that communicate with the stepped hole. The inlet P and outlet T are located on different diameter sections of the stepped hole. A rubber sealing gasket (10) is provided on the step surface of the stepped hole. The elastic recovery plate (11) and the fixed bracket (3) are located at both ends of the stepped hole and are fixedly installed on both sides of the main valve body (2). The optical axis (6) is fixedly installed in the fixed bracket (3) at one end away from the main valve body (2). An expansion sleeve (7) is sleeved on the outside of the optical axis (6) and the expansion sleeve (7) is fixedly installed in the fixed bracket (3). The conical valve core (1) is a stepped column structure adapted to the stepped hole and is movably installed in the stepped hole. The stepped surface of the stepped column contacts or separates from the rubber sealing gasket (10). An annular groove is provided in the middle of the stepped column. One end of the conical valve core (1) is fixedly connected to the center of the elastic recovery plate (11). The fixed bracket (3) is a hollow frame structure. The piezoelectric actuator includes a displacement amplification mechanism disposed in the fixed bracket (3) and a piezoelectric stack (5) fixedly connected in the displacement amplification mechanism. One end of the displacement amplification mechanism is fixedly connected to the end of the conical valve core (1) located in the fixed bracket (3) through a hexagonal stud (8). The other end of the displacement amplification mechanism is fixedly connected to the end of the optical axis (6) located in the fixed bracket (3). The displacement amplification mechanism is a half-bridge amplification mechanism (4) or a two-stage bridge amplification mechanism (4.2). The half-bridge amplification mechanism (4) includes a strip-shaped base (4.13), lever arms (4.14) on both sides of the base (4.13), an output end (4.12) between the other ends of the two lever arms (4.14), and an input end (4.11) on the inside of the lever arms (4.14). One end of the lever arm (4.14) is connected to the base (4.13) via a flexible hinge (4.16). The two ends of the output end (4.12) are respectively connected to the other ends of the two lever arms (4.14) via flexible arms (4.15). The two input ends (4.11) are respectively connected to the two lever arms (4.14) via flexible hinges (4.16). The input end (4.11) is located in the middle of the lever arm (4.14) near the base (4.13). The secondary bridge amplification mechanism (4.2) includes a first-stage amplification mechanism (4.21) and a second-stage amplification mechanism (4.22) located outside the first-stage amplification mechanism (4.21). The piezoelectric stack (5) is fixedly connected to the displacement input end of the first-stage amplification mechanism (4.21), and the displacement output end of the first-stage amplification mechanism (4.21) is fixedly connected to the displacement input end of the second-stage amplification mechanism (4.22). Through the elastic deformation of the displacement amplification mechanism, the displacement output by the piezoelectric stack (5) and applied to the input end of the displacement amplification mechanism is amplified and converted into the displacement output end of the displacement amplification mechanism, thereby driving the axial movement of the conical valve core (1). The stepped surface of the conical valve core (1) separates from the rubber sealing gasket (10), and the inlet P and outlet T of the main valve body (2) are connected through the annular groove in the middle of the conical valve core (1).

2. The high-flow pneumatic piezoelectric valve based on a bridge amplification mechanism according to claim 1, characterized in that: The tapered valve core (1) has an O-ring (9) embedded on the outer side of the stepped column, and the O-ring (9) is slidably sealed to the inner wall of the stepped hole of the main valve body (2).

3. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism according to claim 1, characterized in that: The tapered valve core (1) has threaded columns on both ends of the stepped column, and the threaded columns on both sides have the same structure.

4. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism according to claim 1, characterized in that: The fixed bracket (3) and the elastic recovery plate (11) can be interchanged on both sides of the main valve body (2).

5. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism according to any one of claims 1 to 4, characterized in that: The conical valve core (1) is an integrally formed structure. The edge of the stepped surface of its stepped column is provided with an annular protrusion (1.1). The outer side of the annular protrusion (1.1) is provided with an outer conical surface (1.2) and the inner side is provided with an inner conical surface (1.3). The angle between the generatrix of the inner conical surface (1.3) and the axis of the conical valve core (1) is 45°~90°.

6. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism according to claim 1, characterized in that: The elastic recovery plate (11) is a metal sheet elastomer, consisting of several layers of annular supports and several small supports connected between adjacent layers of annular supports. The edge of the elastic recovery plate (11) is fixed to the end face of the main valve body (2), and the center of the elastic recovery plate (11) is connected to the end of the conical valve core (1) by a nut.

7. A high-flow-rate pneumatic piezoelectric valve based on a bridge amplification mechanism according to claim 1, characterized in that: The piezoelectric stack (5) is a stacked piezoelectric ceramic structure and is polarized along the stacking direction. The two ends of the piezoelectric stack (5) are fixedly glued to the inner wall of the input end of the displacement amplification mechanism.

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