CN104405716B - Two ends prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations - Google Patents

Abstract

The invention relates to a low-friction cylinder with multi-mode vibration of a cylinder body caused by a pre-tightened piezoelectric stack at both ends, and the invention relates to the technical field of pneumatic control. The invention aims to overcome the problems of high noise, short service life, high manufacturing difficulty, large volume, oil pollution, small output and low reliability existing in the existing anti-friction structure. Its general-purpose cylinder assembly is provided with a first support leg and a second support leg on both sides of the cylinder tail end respectively, the bottom end surface of the first support leg is connected to an end face of the first piezoelectric stack, and the bottom of the second support leg The end face is connected to one end face of the second piezoelectric stack, the other end face of the first piezoelectric stack and the other end face of the second piezoelectric stack are connected to the end face of the mounting seat, and the fastening bolt is connected to the cylinder after passing through the mounting seat. The bottom of the cylinder tail end is threaded so that the axis line of the fastening bolt coincides with the axis line of the cylinder barrel of the general-purpose cylinder assembly. The invention can reduce more than 50 percent of the friction force between the piston (rod) and the cylinder body under the state of ultrasonic vibration resonance, and has a good effect of reducing friction.

Description

Low-friction Cylinder with Multi-modal Vibration of Cylinder Body Induced by Pre-tightened Piezoelectric Stack at Both Ends

technical field

The invention relates to the technical field of pneumatic control.

Background technique

When the piston of the cylinder is working at a low speed, it often occurs a discontinuous movement phenomenon of running and stopping, that is, the cylinder crawls. Cylinder crawling seriously affects the accuracy of pneumatic transmission. In order to eliminate this phenomenon, the common method is to superimpose the dither signal on the control signal to compensate the friction of the cylinder. However, the introduction of the dither signal greatly reduces the life of the control valve and brings unnecessary noise and jitter, so the application is limited.

Another method is to use the principle of air flotation to introduce a layer of air film between the friction pairs of the cylinder, thereby significantly reducing the dynamic and static friction of the cylinder, and greatly improving the crawling phenomenon of the cylinder. Such as patent CN102155465A. However, during the manufacturing process of this air-floating low-friction cylinder, high requirements are placed on the machining accuracy of each component, and it is very difficult to manufacture a large-sized air-floating cylinder.

Another method is that the gas-hydraulic joint control servo system is often used in occasions with high requirements for low-speed performance. By increasing the damping of the system, the low-speed crawl of the cylinder has been greatly improved. However, this system is often bulky and prone to oil contamination.

Another method is to use the principle of ultrasonic vibration to reduce friction to paste piezoelectric sheets on the cylinder, and use the ultrasonic vibration output by it to reduce friction. Such as patents CN103195770A, CN103195772A. However, this patch type cylinder has the problems that the output of the piezoelectric sheet is small, and the reliability of the connection with the cylinder is not ideal.

Contents of the invention

The purpose of the present invention is to provide a low-friction characteristic cylinder with multi-modal vibration of the cylinder body caused by the pre-tightened piezoelectric stack at both ends. Problems of large volume, oil pollution, low output, and low reliability.

The present invention relates to a cylinder with low-friction characteristics and multi-modal vibration of the cylinder body caused by pre-tightened piezoelectric stacks at both ends, which includes a general-purpose cylinder assembly, a first piezoelectric stack, a second piezoelectric stack, fastening bolts, mount;

The two sides of the cylinder tail end of the general-purpose cylinder assembly are respectively provided with a first support leg and a second support leg, the bottom end surface of the first support leg is connected to an end face of the first piezoelectric stack, and the bottom end surface of the second support leg is connected to the end face of the first piezoelectric stack. One end face of the second piezoelectric stack is top-connected, the other end face of the first piezoelectric stack and the other end face of the second piezoelectric stack are all connected to the end face of the mounting seat, and the fastening bolts pass through the mounting seat and connect with the end of the cylinder. The bottom is threaded so that the axis line of the fastening bolt coincides with the axis line of the cylinder barrel of the general-purpose cylinder assembly, so that the end face of the mounting seat is parallel to the bottom end face of the first support leg and the bottom end face of the second support leg , so that the first piezoelectric stack and the second piezoelectric stack are symmetrically arranged on both axial sides of the fastening bolt; both the first piezoelectric stack and the second piezoelectric stack are longitudinally vibrating piezoelectric stacks; when the first piezoelectric stack When the driving phase difference between the stack and the second piezoelectric stack is 180°, the entire cylinder is in the bending vibration mode; when the driving phase difference between the first piezoelectric stack and the second piezoelectric stack is 0°, the entire cylinder is in the Longitudinal vibration mode.

The invention can reduce more than 50 percent of the friction force between the piston (rod) and the cylinder body under the state of ultrasonic vibration resonance, and has a good effect of reducing friction. The invention is a low-friction cylinder designed based on the principle of ultrasonic friction reduction, which enables the vibration mode of the vibration cylinder to be switched by changing the phase difference of the input signal. It has a compact structure, can realize multi-mode vibration, has the characteristics of large output force, large output amplitude, easy processing, and strong applicability, and has broad application prospects in the field of low-speed cylinders. It also has the advantages of low noise, long life, easy manufacture, large output and high reliability.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention,

Fig. 2 is a schematic diagram of the overall structure of the second embodiment.

detailed description

Specific embodiment 1: This embodiment is described in conjunction with FIG. 1 . This embodiment is composed of a general-purpose cylinder assembly 1, a first piezoelectric stack 2, a second piezoelectric stack 3, fastening bolts 4, and a mounting seat 5;

The two sides of the tail end of the cylinder barrel 1-1 of the general-purpose cylinder assembly 1 are respectively provided with a first support foot 1-2 and a second support foot 1-3, and the bottom end surface of the first support foot 1-2 is connected with the first piezoelectric One end face of the stack 2 is top-connected, the bottom end face of the second support leg 1-3 is connected to one end face of the second piezoelectric stack 3, the other end face of the first piezoelectric stack 2, the other end face of the second piezoelectric stack 3 Both are top-connected with the end face 5-1 of the mounting seat 5, and the fastening bolt 4 passes through the mounting seat 5 and is threadedly connected with the bottom of the cylinder barrel 1-1 tail end, so that the axis line of the fastening bolt 4 is aligned with the general-purpose cylinder assembly The axis line of the cylinder barrel 1-1 of 1 coincides, so that the end surface 5-1 of the mounting seat 5 is parallel to the bottom end surface of the first support foot 1-2 and the bottom end surface of the second support foot 1-3, so that the first The piezoelectric stack 2 and the second piezoelectric stack 3 are respectively symmetrically arranged on both axial sides of the fastening bolt 4; the first piezoelectric stack 2 and the second piezoelectric stack 3 are longitudinal vibration piezoelectric stacks; when the first piezoelectric stack When the driving phase difference between the electric stack 2 and the second piezoelectric stack 3 is 180°, the entire cylinder 1-1 is in the bending vibration mode; when the driving phase difference between the first piezoelectric stack 2 and the second piezoelectric stack 3 is At 0°, the entire cylinder 1-1 is in the longitudinal vibration mode.

The area of the bottom end surface of the first support foot 1-2 and the area of the bottom end surface of the second support foot 1-3 are equal to or greater than the end surface areas of the first piezoelectric stack 2 and the second piezoelectric stack 3, that is, the first The end face of the piezoelectric stack 2 and the end face of the second piezoelectric stack 3 are completely covered by the first supporting leg 1-2 and the second supporting leg 1-3 respectively.

The first piezoelectric stack 2 and the second piezoelectric stack 3 are products of Piezomechanik Company—PSt150/5×5/7. The driving waveforms of the first piezoelectric stack 2 and the second piezoelectric stack 3 are sinusoidal or triangular waves. The driving frequency of the first piezoelectric stack 2 and the second piezoelectric stack 3 is in the ultrasonic frequency range, specifically, the resonance frequency of the entire device.

Working principle: when the first piezoelectric stack 2 and the second piezoelectric stack 3 are working, the cylinder barrel 1-1 of the general-purpose cylinder assembly 1 is driven by the first support leg 1-2 and the second support leg 1-3. Longitudinal vibration or bending vibration makes the sealing ring of the cylinder piston and the end cover of the general-purpose cylinder assembly 1 and the corresponding friction pair in a state of high-frequency vibration, and uses the anti-friction effect of high-frequency vibration to reduce the dynamic and static friction coefficient between the friction pairs. The difference, and then weaken the switching of the dynamic and static friction force when it is running at low speed, so as to achieve the purpose of improving the characteristics of the friction force when the cylinder is running at low speed, thereby reducing the crawling phenomenon of the cylinder.

Specific embodiment 2: This embodiment is described in conjunction with FIG. 2. On the basis of specific embodiment 1, this embodiment adds a first H-shaped flexible hinge 6 and a second H-shaped flexible hinge 7; the first H-shaped flexible hinge 6 is set Between the first piezoelectric stack 2 and the end face 5-1, a second H-shaped flexible hinge 7 is arranged between the second piezoelectric stack 3 and the end face 5-1.

This embodiment has the functions of increasing the rotational freedom of the fastening bolt 4 in the axial direction, optimizing the vibration effect, and prolonging the working life of the first piezoelectric stack 2 and the second piezoelectric stack 3 .

Claims (6)

1. prefastening piezoelectric pile in two ends causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, and it comprises universal cylinder assembly (1), the first piezoelectric pile (2), the second piezoelectric pile (3), clamping bolt (4), fitting seat (5);

It is characterized in that cylinder barrel (1-1) the tail end both sides of universal cylinder assembly (1) are respectively arranged with the first supporting foot (1-2) and the second supporting foot (1-3), the bottom end of the first supporting foot (1-2) and the first piezoelectric pile (2) end face apical graftings, the bottom end of the second supporting foot (1-3) and the second piezoelectric pile (3) end face apical graftings, another end face of first piezoelectric pile (2), another end face of second piezoelectric pile (3) all with end face (5-1) apical grafting of fitting seat (5), clamping bolt (4) is connected with cylinder barrel (1-1) tail end bottom thread afterwards through fitting seat (5), the shaft axis of clamping bolt (4) is overlapped with the shaft axis of the cylinder barrel (1-1) of universal cylinder assembly (1), make the end face of fitting seat (5) (5-1) parallel relative with the bottom end of the second supporting foot (1-3) with the bottom end of the first supporting foot (1-2), the first piezoelectric pile (2) and the second piezoelectric pile (3) is made to be symmetricly set on the axial both sides of clamping bolt (4) respectively, first piezoelectric pile (2) and the second piezoelectric pile (3) are all extensional vibration piezoelectric pile, when the first piezoelectric pile (2) is 180 ° with the driving phase difference of the second piezoelectric pile (3), whole cylinder barrel (1-1) is flexural vibration mode, when the first piezoelectric pile (2) is 0 ° with the driving phase difference of the second piezoelectric pile (3), whole cylinder barrel (1-1) is longitudinal vibration mode.

2. two ends according to claim 1 prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, it is characterized in that the area of described first supporting foot (1-2) bottom end is equal to or greater than the face area of the first piezoelectric pile (2), the area of the second supporting foot (1-3) bottom end is equal to or greater than the face area of the second piezoelectric pile (3), and namely the end face of the first piezoelectric pile (2), the end face of the second piezoelectric pile (3) are covered completely by the first supporting foot (1-2), the second supporting foot (1-3) respectively.

3. two ends according to claim 1 prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, it is characterized in that described first piezoelectric pile (2) and the second piezoelectric pile (3) are Piezomechanik Products-PSt150/5 × 5/7.

4. two ends according to claim 1 prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, it is characterized in that the drive waveforms of described first piezoelectric pile (2) and the second piezoelectric pile (3) is for sinusoidal or pyramidal wave.

5. two ends according to claim 1 prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, the driver frequency that it is characterized in that described first piezoelectric pile (2) and the second piezoelectric pile (3) is supersonic band, the specifically resonant frequency of whole device.

6. two ends according to claim 1 prefastening piezoelectric pile causes the low frictional behavior cylinder of cylinder body multiple modal vibrations, it is characterized in that its increase has the first H-shaped flexible hinge (6) and the second H-shaped flexible hinge (7); First H-shaped flexible hinge (6) is arranged between the end face (5-1) of the first piezoelectric pile (2) and fitting seat (5), and the second H-shaped flexible hinge (7) is arranged between the end face (5-1) of the second piezoelectric pile (3) and fitting seat (5).