CN102979849B - Active-type piezoelectric hydraulic damper - Google Patents

Abstract

The invention relates to an active-type piezoelectric hydraulic damper, belonging to shock absorbers. The active-type piezoelectric hydraulic damper is characterized in that an end cover is fixedly arranged on a cylinder body, and a cavity of the cylinder body is partitioned into an upper cylinder cavity and a lower cylinder cavity by a big piston; a balance spring is pressed in the lower cylinder cavity by the big piston, and a piston rod flange is fixedly arranged on the big piston; a piezoelectric stack is arranged in a piston rod and is used for pressing a small piston, a valve core and a reset spring in the cavity of the big piston; a disc spring is pressed between the small piston and the piston rod flange; a valve spring and a valve ball are crimped in a cavity of the piston core in sequence by the small piston to form a one-way valve; the cavity of the valve core is communicated with an upper valve cavity, a lower valve cavity and an annular slot in the valve core; and the annular slot is communicated with a left runner and a right runner in the big piston to form a damper valve, and the left runner and the right runner are further communicated with the upper cylinder cavity and the lower cylinder cavity. The active-type piezoelectric hydraulic damper has the advantages of simple structure, small size, no leakage and or electromagnetic interference and wide damping adjusting range because the piezoelectric stack in the piston rod drives an additional fluid cavity piston to adjust the damper value in the piston.

Description

An Active Piezoelectric Hydraulic Damper

technical field

The invention belongs to the technical field of vibration reduction, and in particular relates to an active piezoelectric hydraulic damper, which is suitable for vibration suppression and elimination of vehicles, mechanical equipment and the like.

Background technique

Hydraulic dampers have been widely used in the field of vibration control of vehicles and mechanical equipment. The early passive hydraulic dampers were simple in structure, low in cost, and relatively mature in technology, but because the damping was not adjustable, their damping effect and environmental adaptability were poor, and they were not suitable for some occasions that required better vibration control effects, such as automobile engines. And frame suspension, vibration reduction of large precision instruments and equipment, etc. Therefore, people have proposed active and semi-active adjustable hydraulic dampers, that is, active adjustable dampers that use motor-driven hydraulic pumps to provide power and are controlled by electromagnetic reversing/overflow/pressure reducing valves, such as China Invention patents CN1367328A, CN101392809A, etc. Compared with the passive non-adjustable hydraulic damper, the active adjustable hydraulic damper has better control effect and strong adaptability to the vibration environment, and has been successfully applied in the active suspension of automobiles; however, the existing active hydraulic damper Most of them require a larger pumping station to drive and combine multiple solenoid valves for joint control. Therefore, the system is bulky, the connection and control are complicated, the energy consumption is high, and the reliability is low. There are certain limitations in application. In view of the problems of the existing active hydraulic damper's own structure, control ability and dependence on external energy supply, the applicant once proposed a semi-active self-supply damper based on the coupling of piezoelectric stack transducers and fluid to recover energy and perform damping adjustment. The energy-adjustable damper, that is, Chinese patent 201110275849.6, can solve some disadvantages of conventional active hydraulic dampers to a certain extent; The expansion and contraction ability of the stack under the action of voltage is extremely limited, only at the micron level, so the damping adjustment ability is low, and it is not suitable for occasions with a large adjustment range.

Contents of the invention

The present invention proposes an active piezoelectric hydraulic damper to solve the problems of the existing active hydraulic damper and the piezoelectric stack self-powered adjustable hydraulic damper, which have low damping adjustment ability and are not suitable for a large adjustment range. Occasion problem.

The technical solution adopted by the present invention is: the end cover is fixed on the cylinder body by screws, the large piston is sleeved in the cylinder cavity and the cylinder cavity is divided into an upper cylinder cavity and a lower cylinder cavity; the balance spring is pressed by the large piston Connected in the lower cylinder chamber, the flange at the end of the piston rod is fixed on the large piston by screws; the piezoelectric stack is placed in the inner cavity of the piston rod, and the small piston, valve core and return spring are crimped on the large piston in sequence. In the stepped inner cavity; the disc spring is crimped between the small piston and the flange at the end of the piston rod, and the upper shoulder of the small piston is against the flange at the end of the piston rod; the small piston and the large piston and the valve The spools together form the upper valve cavity, the spool and the large piston together form the lower valve cavity, the upper valve cavity communicates with the accumulator through the pipeline; the small piston presses the valve spring and the valve ball inside the spool in turn. In the cavity, the inner cavity of the valve core, the valve spring and the valve ball together constitute a one-way valve; the inner cavity of the valve core communicates with the upper valve cavity through the horizontal groove on the upper end of the valve core, and communicates with the lower valve cavity through the longitudinal hole on the valve core. , and communicate with the ring groove on the valve core through the vertical hole and the horizontal hole on the valve core; the ring groove is connected with the left flow channel and the right flow channel on the large piston, and the left flow channel and the right flow channel are also connected. They are respectively communicated with the upper cylinder chamber and the lower cylinder chamber; the ring groove, the left flow channel and the right flow channel jointly constitute a damping valve for damping adjustment.

Before work, the damper system is filled with fluid, and the fluid pressures in the upper and lower cylinder chambers and the upper and lower valve chambers are equal, which are the accumulator preset pressure P ₀ . When the damper is not working, the piezoelectric stack is not energized and is not affected by the pre-tightening force; the large piston and the small piston are in a balanced state under the action of fluid pressure and various springs, the damper valve is in a normally open state, and the system damping is small.

When the damping needs to be adjusted, the piezoelectric stack is energized and stretched, pushing the small piston down, so that the fluid pressure in the upper valve chamber increases to P, and the check valve remains closed; when the upper end of the spool 7 is subjected to When the external force F _s =F _t8 +πr ² P is greater than the external force F _x =F _t10 +πr ² P ₀ on the lower end, that is, the fluid pressure in the upper valve chamber increases to P＞[F _t10 -F _t8 +πr ² P ₀ ] /(πr ² ), the spool starts to move downward, which reduces the flow area of the damping valve and increases the damping. In the formula: F _t8 and F _t10 are the force of the valve spring and the return spring on the spool respectively, r is the radius of the spool; when the elongation of the piezoelectric stack under the action of voltage is L=Vη, the movement of the spool, that is, the opening adjustment of the damping valve is l=(R/r) ² L= (R/r) ² Vη, where V is the driving voltage of the piezoelectric stack, η is a coefficient related to the structural size and fluid pressure of the piezoelectric stack, disc spring, return spring and valve spring, and R is the large piston Therefore, when the diameter of the large piston is much larger than the diameter of the small piston, the elongation of the piezoelectric stack will be amplified by n=l/L=(R/r) ² times, that is, the damping adjustment ability of the damping valve will be magnified Magnify n=(R/r) ² times.

When the piezoelectric stack is powered off or the driving voltage is reduced, the piezoelectric stack begins to shrink under the action of its own elastic force, and the small piston and valve core also move upward under the combined action of the fluid and related springs, so that the damping valve The opening of the valve gradually increases, and the damping gradually decreases; when the shoulder of the small piston leans against the flange of the piston rod, and the upper end surface of the spool leans against the lower surface of the small piston, the damper returns to the initial state. At this time, the opening of the damping valve is the largest and the damping is the smallest.

The features and advantages of the present invention are: ① An additional fluid cavity that can be filled with fluid is added between the piezoelectric stack and the spool, and the displacement of the spool is increased by combining the larger piston with the smaller spool, so The damping adjustment and control range is large; ②The damping valve and piezoelectric stack are placed in the piston and piston rod, without the need for peripheral equipment such as motors, pumps, solenoid valves, etc., so the volume is small, the structure is simple, the integration is high, and the sealing is good. It is easy to use a longer piezoelectric stack to achieve a wide range of damping adjustment; ③The piezoelectric stack is not affected by fluid force when it is not working, so it has a large amount of deformation after power-on and high electromechanical energy conversion efficiency; ④Adopts a non-magnetic piezoelectric stack It drives and controls the movement of the spool, does not produce or is not subject to electromagnetic interference, and is more suitable for strong magnetic field and strong radiation environment. Therefore, the active piezoelectric hydraulic damper of the present invention is not only suitable for large-scale vehicles and machine tools, but also suitable for micro-systems and remote control systems such as aerospace and intelligent structures.

Description of drawings

Fig. 1 is a structural sectional schematic view of a preferred embodiment of the present invention when the damper is not working;

Fig. 2 is a structural sectional schematic view of a preferred embodiment of the present invention when the damper of a preferred embodiment of the present invention works;

Fig. 3 is an enlarged view of part I of Fig. 1;

Fig. 4 is a structural sectional schematic diagram of a large piston of a preferred embodiment of the present invention;

Fig. 5 is a structural sectional schematic view of a valve core of a preferred embodiment of the present invention;

FIG. 6 is a left side view of FIG. 5 .

Detailed ways

The end cover 3 is fixed on the cylinder body 4 by screws, the large piston 5 is socketed in the inner cavity of the cylinder body 4 and divides the inner cavity of the cylinder body 4 into an upper cylinder chamber C11 and a lower cylinder chamber C12; the balance spring 10 passes through the large piston 5 It is crimped in the lower cylinder cavity C12, and the flange 102 at the end of the piston rod 1 is fixed on the large piston 5 by screws; the piezoelectric stack 2 is placed in the inner cavity 101 of the piston rod 1, and the small piston 6, valve The core 7 and the return spring 11 are crimped in the stepped inner cavity C2 of the large piston 5; a disc spring 12 is crimped between the small piston 6 and the flange 102 of the piston rod 1, and the shoulder 601 of the small piston 6 is on the top Lean on the flange 102 of the piston rod 1; the upper valve cavity C21 is formed between the small piston 6, the large piston 5 and the valve core 7, the lower valve cavity C22 is formed between the valve core 7 and the large piston 5, and the upper valve cavity C21 communicates with the accumulator 13 through the pipeline; the small piston 6 presses the valve spring 8 and the valve ball 9 in the inner cavity 705 of the valve core 7 in turn, and the inner cavity 705 of the valve core 7, the valve spring 8 and the valve ball 9 Together they constitute the one-way valve F1; the inner cavity 705 of the spool 7 communicates with the upper valve cavity C21 through the transverse groove 704 at the upper end of the spool 7, communicates with the lower valve cavity C22 through the longitudinal hole 701 on the spool 7, and communicates with the lower valve cavity C22 through the spool 7. The vertical hole 701 and the horizontal hole 702 on the 7 communicate with the annular groove 703 on the spool; the annular groove 703 on the spool 7 communicates with the left flow channel 502 and the right flow channel 501 on the large piston 5, and the left flow channel 502 communicates with the right flow channel 501 and communicates with the upper cylinder chamber C11 and the lower cylinder chamber C12 respectively; the annular groove 703 on the spool 7 and the left flow channel 502 and the right flow channel 501 on the large piston 5 jointly form a damping adjustment The damping valve F2.

Fill the damper with fluid before work. During the fluid filling process, the one-way valve F1 is opened, and the fluid enters the upper valve cavity C21 through the one-way valve F2; after the fluid is filled, the upper cylinder cavity C11, the lower cylinder cavity C12, and the upper valve cavity The fluid pressures in C21 and the lower valve cavity C22 are equal to the preset pressure P ₀ of the accumulator 12 .

When the damper is not working, the piezoelectric stack 2 is not energized; the fluid force on the upper and lower sides of the large piston 5 is equal, and is in a balanced state under the action of the vibrating body M and the balance spring 10; 11 and the disc spring 12 lean against the flange 102 of the piston rod 1 to prevent the piezoelectric stack 2 from being pre-compressed by the fluid; Under the action of the return spring 11 and the valve spring 8, it leans against the lower surface of the small piston 6 to ensure that the damping valve F2 is in a normally open state, that is, the left flow channel 502 and the right flow channel 501 on the large piston 5 and the valve core 7 The ring groove 703 on the top is completely connected, and the damping of the system is small at this time;

When the vibration body M vibrates up and down and needs to be controlled, the piezoelectric stack 2 is energized and stretched, pushing the small piston 6 to move downward, thereby increasing the fluid pressure in the upper valve chamber C21 and maintaining the one-way valve F2 at Closed state; when the fluid pressure in the upper valve cavity C21 increases, the external force F _s =F _t8 +πr ² P on the upper end of the valve core 7 is greater than the external force F _x =F _t10 +πr ² P ₀ on the lower end, that is, the upper valve cavity C21 When the pressure of the internal fluid increases to P>[F _t10 -F _t8 +πr ² P ₀ ]/(πr ² ), the valve core 7 starts to move downward, and the fluid in the lower valve cavity C22 passes through the longitudinal hole on the valve core 7 701, the horizontal hole 702 and the annular groove 703 are discharged and enter the left flow channel 502 of the large piston 5; the downward movement of the spool 7 causes the flow area of the damping valve F2 to decrease, thereby increasing the damping effect. In the above formula : F _t8 and F _t10 are respectively the active force of the valve spring 8 and the return spring 10 on the valve core, and r is the radius of the valve core; if the elongation of the piezoelectric stack 2 under the action of voltage is L=Vη, then the valve core 7, that is, the opening adjustment of the damping valve F2 is l=(R/r) ² L=(R/r) ² Vη, wherein: V is the driving voltage of the piezoelectric stack 2, and η is the Electric stack 2, disc spring 12, return spring 10 and valve spring 8 are related to the structural dimensions and fluid pressure coefficients, R is the radius of the large piston 5; therefore, when the diameter of the large piston 5 is much larger than the diameter of the small piston 6 ,Right now , the elongation of the piezoelectric stack 2 will be amplified by n=l/L=(R/r) ² times, that is, the damping adjustment capability of the damping valve will be magnified by (R/r) ² times;

When the piezoelectric stack 2 is powered off or the driving voltage is reduced, the piezoelectric stack 2 starts to shrink under the action of its own elastic force, and the small piston 6 and the valve core 7 also move upward under the combined action of the fluid and various related springs , so that the opening of the damping valve F2 gradually increases, and the damping gradually decreases; at the same time, the fluid pressure in the lower valve chamber C22 decreases, and the fluid flows from the left flow channel 502 on the large piston 5 through the annular groove 703 on the valve core 7, the horizontal The hole 702 and the longitudinal hole 701 enter the lower valve cavity C22; when the shoulder 601 of the small piston 6 leans against the flange 102 of the piston rod 1, and the upper end surface of the valve core 7 leans against the lower surface of the small piston 6 , the damper returns to the initial state, at this time the opening of the damping valve F2 is the largest and the damping is the smallest.

Claims (1)

1. an Active-type piezoelectric hydraulic damper, end cap is fixed by screws on cylinder body, and large piston sleeve is connected in inner chamber of cylinder block and by inner chamber of cylinder block and is separated into upper cylinder half chamber and lower cylinder chamber, and the flange of piston rod end is fixed by screws on large piston; Belleville spring is crimped with and the shoulder of small piston leans on the flange of piston rod end between small piston and the flange of piston rod end, uuper valve chamber is communicated with accumulator by pipeline, it is characterized in that: balance spring is crimped in lower cylinder chamber by large piston, piezoelectric stack is placed in the inner chamber of piston rod, and is crimped in the ladder-type inner chamber of large piston by small piston, spool and Returnning spring successively; Jointly form uuper valve chamber between small piston and large piston and spool, jointly form lower valve chamber between spool and large piston, valve spring and valve ball are crimped in the inner chamber of spool by small piston successively, and the inner chamber of spool, valve spring and valve ball form one-way valve jointly; The inner chamber of spool is communicated with uuper valve chamber by the translot of spool upper end, is communicated with by the vertical hole on spool with lower valve chamber, is also communicated with the annular groove on spool by the vertical hole on spool and cross-drilled hole; Left runner on described annular groove and large piston and right flow passage, described left runner and right runner are also communicated with lower cylinder chamber with upper cylinder half chamber respectively; Described annular groove and described left runner and right runner are configured for the orifice valve that damping regulates jointly.