CN110242696B

CN110242696B - Variable damping control method of multistage controllable variable damping shock absorber

Info

Publication number: CN110242696B
Application number: CN201910528837.6A
Authority: CN
Inventors: 毕凤荣; 吕振鹏; 马腾; 李鑫; 黄宇
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2019-06-18
Filing date: 2019-06-18
Publication date: 2020-09-08
Anticipated expiration: 2039-06-18
Also published as: CN110242696A

Abstract

The invention relates to a variable damping control method of a multistage controllable variable damping shock absorber, which realizes the effect of multistage variable damping by jointly adjusting the damping coefficient, pressure and flux of magnetorheological fluid in the shock absorber according to the magnitude of a vibration signal detected by an acceleration sensor, and comprises the following steps: (1) controlling the current passing through coil windings on two sides of the working piston and generating magnetic fields with different magnetic induction intensities, so that the damping coefficient of the magnetorheological fluid is changed; (2) controlling the position of a pretightening force control rotor in the working piston, so that two channels in the pretightening force control rotor are respectively connected with an extension valve and a compression valve of a one-way valve spring with different pretightening forces; (3) the position of a flow control disc at the lower end of the working piston is controlled, so that two channels in the pretightening force control rotor are respectively connected with circulation holes with different apertures, and the damping of the shock absorber is controlled.

Description

Variable damping control method of multistage controllable variable damping shock absorber

Technical Field

The invention belongs to the field of dampers and intelligent materials, and particularly relates to a rotary type magnetorheological fluid damper with multistage adjustable damping force.

Background

Mechanical vibration is commonly existing in various power machines and mechanical products, and the vibration can cause damage to mechanical parts, influence the working effect of precision instruments and even generate adverse effects on human bodies. In the fields of aviation, aerospace, machinery, construction, precision instruments and the like, the adverse effects of vibration are mainly eliminated through a vibration damper. The types of the shock absorbers at present are classified into a passive control type, an active control type and a semi-active control type according to a control manner.

The passive vibration absorber consists of a spring and a vibration absorber, and the performance parameters of the passive vibration absorber, namely the rigidity and the damping coefficient, cannot be changed once being determined, so that the vibration absorbing performance is optimal only under a certain bearing mass and a certain excitation frequency; the active vibration damper is added with a controllable force generator on the basis of a passive vibration damper, vibration damping control is realized by controlling the acting force of the force generator, the active vibration damper has good active vibration damping effect, but needs an energy device for providing control force from the outside, and has high manufacturing cost, large energy consumption and low reliability; the semi-active control shock absorber has adjustable rigidity or damping coefficient, better shock absorption performance than a passive shock absorber, lower energy consumption than the active control shock absorber and higher comprehensive performance.

The magnetorheological fluid is an intelligent electrorheological material, and can be quickly and reversibly converted from Newtonian fluid with good flowing property into Bingham elastoplastomer with high viscosity and low fluidity under the action of magnetic field force. The magnetorheological fluid can rapidly change the state of the magnetorheological fluid along with the change of an external magnetic field, so that the yield stress and the apparent viscosity of the whole suspension liquid are changed by 2-3 orders of magnitude. Due to the advantages, the magnetorheological fluid damper has good application prospect as a semi-active damper.

Although the magnetorheological fluid shock absorber has the advantages of simple structure, low energy consumption, adjustable output damping force, quick response and the like, so that the magnetorheological fluid shock absorber is widely applied to the fields of automobile suspension, buildings, bridge shock absorption and the like, some problems still need to be solved at present: most of the magnetorheological fluid shock absorbers used at the present stage belong to a piston gap flow mode, and the range of the damping force which can be provided by the magnetorheological fluid shock absorbers is limited due to the defects of narrow adjustable range of the damping force, small action area of a magnetic field, low utilization rate of the magnetorheological fluid and the like; and the magnetorheological fluid shock absorber generates small damping force at low speed, particularly when the speed is close to zero, so that the automobile can not provide enough damping force when working on a non-paved road surface at low speed or bending at low speed, thereby influencing the operating stability and smoothness of the automobile. In order to obtain larger output damping force, the traditional proposal is mostly a method for increasing the length of the damping gap, but the method can cause the volume of the magnetorheological damper to become larger.

Disclosure of Invention

The invention aims to provide a variable damping control scheme of a rotary type magnetorheological fluid shock absorber with multistage adjustable damping force, so that the shock absorber has the advantages of large adjustable damping force range, high adjustment stage number, good low-frequency damping performance and the like, the smoothness of a vehicle in low-speed running can be improved, and the operation stability can be improved. The technical scheme of the invention is as follows:

a variable damping control method of a multistage controllable variable damping shock absorber adopts the multistage controllable variable damping shock absorber, which comprises a working cylinder 21 and a floating piston 3 positioned in the working cylinder 21, wherein the working cylinder is divided into a closed air chamber 2 filled with high-pressure gas and a liquid cavity containing magnetorheological fluid 4 serving as working liquid by the floating piston 3;

a working piston 5 with a hollow cavity is arranged in a cavity containing magnetorheological fluid 4 serving as working fluid, a ring groove is formed in the side wall of the working piston, and an excitation coil 18 is wound in the ring groove and used for adjusting the damping coefficient of the working fluid in the working cylinder; a pre-tightening force control rotor 15 is arranged in a hollow cavity of the working piston 5, a plurality of extension valves 26 and a plurality of compression valves 27 are symmetrically distributed on the upper part of the working piston 5, pre-tightening springs with different pre-tightening forces are arranged on the extension valves and the compression valves, a flow control disc 19 is arranged at the lower end of the working piston, circulation holes with different apertures are formed in the flow control disc 19, two channels are arranged in the pre-tightening force control rotor 15 and used for connecting the extension valves and the compression valves with different pre-tightening forces with the circulation holes with different apertures, and the compression valves and the extension valves are respectively opened in the compression and extension processes of the shock absorber and are used for controlling the pressure of working fluid in the compression and extension processes;

a piston rod 11 is fixed on the working piston, a control chamber is arranged on the piston rod, a stepping motor 22 and a deflector rod 15 are arranged in the control chamber, and the stepping motor 22 controls the pretightening force control rotor and the flow control disc through the control rod.

According to the magnitude of the vibration signal detected by the acceleration sensor, the effect of multistage variable damping is realized by jointly adjusting the damping coefficient, the pressure and the flow of the magnetorheological fluid in the shock absorber, and the control method comprises the following steps:

(1) controlling the current passing through coil windings on two sides of the working piston and generating magnetic fields with different magnetic induction intensities, so that the damping coefficient of the magnetorheological fluid is changed;

(2) controlling the position of a pretightening force control rotor in a working piston to ensure that two channels in the pretightening force control rotor are respectively connected with a stretching valve and a compression valve of a one-way valve spring with different pretightening forces, when the pressure of magnetorheological fluid in a working cylinder reaches the pretightening force of the spring, the stretching valve or the compression valve is opened, the working fluid circulates, and the change of the damping force of the shock absorber in the stretching and compression processes is formed through the throttling effect of the stretching valve and the compression valve on the magnetorheological fluid;

(3) the position of a flow control disc at the lower end of the working piston is controlled, so that two channels in the pretightening force control rotor are respectively connected with circulation holes with different apertures, and the flow control of the magnetorheological fluid in the working piston is realized by controlling the size of the circulation holes in the flow control disc in the process of stretching and compressing the shock absorber, thereby realizing the control of the damping of the shock absorber.

Preferably, the bottom end of the control rod, the bottom end of the pretightening force control rotor and the upper end of the flow control panel are respectively provided with a gear ring, the inner side and the outer side of the joint sleeve 17 are respectively provided with teeth meshed with the gear ring at the bottom end of the control rod and teeth meshed with the gear ring at the bottom end of the pretightening force control rotor and the gear ring at the upper end of the flow control panel, the inner side teeth of the joint sleeve are always meshed with the gear ring at the bottom end of the control rod, and the two sides of the end parts of all the gear rings and the joint sleeve teeth are respectively provided with a reverse inclined surface so as to facilitate the joint of the joint sleeve and different.

The invention has the positive effects that:

the adjusting range of the damping force is larger, and the damping force adjusting device is suitable for more fields.

And (II) the damping force output control is more accurate, the damping force output is divided into a plurality of levels, more ideal damping force selection can be realized according to different working conditions, and the control effect is better.

And (III) in a low-speed and low-frequency environment, the damping device can have large damping performance, and not only can improve the smoothness of the vehicle, but also can improve the steering stability of the vehicle.

Drawings

Fig. 1 is a schematic structural view of a shock absorber used in the present invention, fig. 2 is a schematic structural view of a working piston, fig. 3 is a sectional structural view of the working piston a-a, fig. 4 is a sectional structural view of the working piston B-B, fig. 5 is a schematic structural view of a joint sleeve, and fig. 6 is a schematic structural view of a control chamber, in which:

1-lower hoisting ring 2-sealed air chamber 3-floating piston 4-magnetorheological fluid 5-working piston 6-pretension control rotor 7-extension valve spring 8-control rod 9, 16-sliding bearing 10-upper hoisting ring 11-piston rod 12-control chamber 13-gland nut 14-compression valve spring, 15-shifting rod 17-joint sleeve 18-excitation coil 18-flow control disc 20-O type sealing ring 21-working cylinder 22-stepping motor 23-pretension spring 24-shifting fork control rod 25-shifting fork 26-extension valve 27-compression valve 28-throttling hole

Detailed Description

The present invention is further described in detail below by way of specific examples, which enable a person skilled in the art to more fully understand the invention without in any way limiting it.

The invention respectively adjusts the pretightening force control rotor and the flow control disc through the stepping motor, thereby realizing the control of the pressure and the circulation of the working fluid in the cylinder, realizing the adjustment of the damping coefficient of the working fluid in the cylinder through the matching of the pretightening force control rotor and the flow control disc and the control of the current of the magnet exciting coil, and finally realizing the aim of multistage controllable damping. The shock absorber is large in damping, wide in damping force adjusting range and high in reliability, is suitable for working in multiple fields, has large damping performance at low frequency, and can improve the smoothness of a vehicle and the operating stability of the vehicle.

As shown in fig. 1, the floating piston 3 is located in the working cylinder 21 and forms a sealed sliding fit with the inner wall of the cylinder, one end of the floating piston and one end of the working cylinder form a sealed air chamber 2, and high-pressure air is filled in the sealed air chamber, so that high-frequency vibration generated when sudden impact is applied can be effectively reduced, and noise can be eliminated. The other end of the floating piston is provided with working fluid (magnetorheological fluid 4), and the floating piston is provided with an O-shaped sealing ring 20 with a large section to completely separate oil from gas. The working piston 5 is positioned in the working fluid at the upper part of the air chamber, annular grooves are formed in two sides of the working piston, and magnet exciting coils 18 are wound in the annular grooves and are used for adjusting the damping coefficient of the working fluid in the working cylinder. The interior of the working piston is provided with a pretightening force control rotor 15 and a flow control disc 19 which are respectively used for controlling the pressure of the working fluid in the working cylinder and the flow rate of the working fluid. The piston rod 11 and the working piston are fixed together by a compression nut 13. The piston rod is welded with a control chamber, and a stepping motor 22 and a shifting

rod adjuster

23, 24 and 25 are arranged in the control chamber and are used for respectively controlling the rotation of the pretightening force control rotor and the flow control disc.

As shown in fig. 2, the working piston is divided into an upper part, a middle part and a lower part along the axial direction of the working piston, the sectional views of the upper part and the lower part of the working piston are shown in fig. 3 and 4, the upper part of the working piston is symmetrically distributed with the same number of extension valves 26 and compression valves 27, and the compression valves and the extension valves are respectively opened in the compression and extension processes of the shock absorber and are used for controlling the pressure of working fluid in the compression and extension processes. The pre-tightening springs 7 and 14 with different pre-tightening forces are arranged on the extension valve and the compression valve, when the oil pressure acting force acting on the valve and the spring force are in the same direction, the valve is in a closed state and is not communicated completely, and when the oil pressure acting force and the spring force are opposite, the valve can be opened as long as the pressure is greater than the pre-tightening force. The pretightening force control rotor is positioned in the middle of the working piston, is of an irregular cylindrical structure, can rotate around an axis, and is internally provided with two channels for connecting the expansion valve and the compression valve with different pretightening forces with circulation holes with different apertures. The lower part of the piston is provided with a flow control disc 18, and the flow control disc is symmetrically provided with circulation holes with different apertures for controlling the circulation of the magnetorheological fluid passing through the working piston, thereby achieving the effect of changing the damping. Rotating the pretightening force control rotor according to the vibration reduction requirement, and selecting a compression valve and an extension valve with proper pretightening force; after the pretightening force is selected, the flow control disc is rotated, and the circulation hole with the proper aperture is selected. When the shock absorber is in a compression stroke, the volume of a chamber below the piston is reduced, the pressure of working fluid is increased, and the working fluid flows to the chamber above the piston through the compression valve 27, at the moment, a right channel of the whole piston is communicated, and a left channel is closed; similarly, when the shock absorber is in the extension stroke, the volume of the chamber above the piston is reduced, the working fluid pressure is increased, and the working fluid flows to the chamber below the piston through the extension valve 26, and the left channel of the whole piston is communicated and the right channel is closed.

The stepping motor 22 controls the pretightening force control rotor and the flow control disc through a control rod. As shown in fig. 5, the bottom end 8 of the control rod, the bottom end 6 of the pretightening force control rotor and the upper end 18 of the flow control panel are respectively provided with a gear ring, the inner side and the outer side of the joint sleeve 17 are respectively provided with teeth meshed with the gear ring at the bottom end of the control rod and teeth meshed with the gear ring at the bottom end of the pretightening force control rotor and the gear ring at the upper end of the flow control panel, the inner side teeth of the joint sleeve are always meshed with the gear ring at the bottom end of the control rod, and both sides of the end parts of all the gear rings and the. When the shifting lever 15 moves upwards, the joint sleeve moves upwards under the pushing of the shifting lever, the outer side teeth of the joint sleeve are meshed with the gear ring at the bottom end of the pretightening force control rotor, the joint of the control rod and the pretightening force control rotor is realized under the action of the joint sleeve, and the pretightening force control rotor can be adjusted by rotating the control rod. Similarly, when the shifting lever moves downwards, the joint sleeve moves downwards, the control rod is connected with the flow control panel under the action of the joint sleeve, and the control rod is rotated to realize the adjustment of the flow control panel.

As shown in fig. 6, a stepping motor 22 and a shift lever adjusting

device

23, 24, 25 are installed in the control chamber, the stepping motor controls a pretightening force control rotor and a flow control disc in the working piston through a control rod 8, and the shift lever adjusting device realizes the up-and-down movement of the shift lever through the combined action of a pretightening spring 23, a shift fork control rod 24 and a shift fork 25, so as to push the engaging sleeve to move up and down. Under the ordinary state, the driving lever is located at the lowest position under the action of the pre-tightening spring, when the shifting fork control rod is electrified, the shifting fork control rod pushes one end of the shifting fork to move downwards, and the other end of the shifting fork pushes the driving lever to overcome the pre-tightening force of the spring to move upwards under the lever action. The pretightening force control rotor and the flow control disc are respectively connected with the adjusting rod through the up-and-down movement of the deflector rod. Finally, the damping coefficient, the working pressure and the flow of the working liquid in the cylinder are controlled to realize the adjustment of large-range and multi-stage damping force.

When the vibration absorber works under a certain working condition, the external sensor transmits the detected acceleration signal to the processor, generates a corresponding control signal according to the required vibration reduction requirement after analysis, and transmits the control signal to the direct current stabilized voltage power supply and a control chamber on the piston rod respectively; the control chamber can firstly adjust the pressure of the working fluid according to the received signal, the deflector rod moves upwards under the action of the deflector rod adjusting device, the engaging sleeve connects the pre-tightening force control rotor with the control rod, and the stepping motor rotates the control rod according to the received signal to rotate the pre-tightening force control rotor to an ideal position. When the oil pressure acting force on the valve is in the same direction with the spring force, the valve is in a closed state and is not communicated completely, and when the oil pressure acting force is opposite to the spring force, the valve can be opened as long as the pressure is greater than the pretightening force, and meanwhile, the valve body is internally made into an inverted trapezoidal structure, so that the flow of the working liquid flowing through the working piston can be controlled to a certain degree. And after the working fluid pressure in the working cylinder is adjusted, the flow of the working fluid in the working cavity is adjusted. The joint sleeve moves downwards under the pushing of the deflector rod, the control rod is connected with the flow control disc, and the stepping motor rotates the adjusting rod according to the received signal to adjust the flux of the working fluid flowing through the working piston. When the stepping motor adjusts the pretightening force control rotor and the flow control disc, the direct-current stabilized voltage power supply can control the input current of the magnet exciting coil according to the received signals, so that the damping coefficient of the working fluid in the working cylinder is adjusted. The multi-stage adjustment of the damping of the shock absorber is realized by the above-mentioned combined action.

The present invention is not limited to the above-described embodiments. The foregoing description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above specific embodiments are merely illustrative and not restrictive. Those skilled in the art can make many changes and modifications to the invention without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A variable damping control method of a multistage controllable variable damping shock absorber is provided, the adopted multistage controllable variable damping shock absorber comprises a working cylinder and a floating piston positioned in the working cylinder, the working cylinder is divided into a closed air chamber filled with high-pressure gas and a liquid cavity containing magnetorheological fluid serving as working liquid by the floating piston;

a working piston with a hollow cavity is arranged in a cavity containing magnetorheological fluid serving as working fluid, a ring groove is formed in the side wall of the working piston, and an excitation coil is wound in the ring groove and used for adjusting the damping coefficient of the working fluid in the working cylinder; a pretightening force control rotor is arranged in a hollow cavity of the working piston, a plurality of extension valves and a plurality of compression valves are symmetrically distributed at the upper part of the working piston, pretightening springs with different pretightening forces are arranged on each extension valve and the compression valve, a flow control disc is arranged at the lower end of the working piston, circulation holes with different apertures are formed in the flow control disc, two channels are arranged in the pretightening force control rotor and are used for connecting the extension valves and the compression valves with different pretightening forces with the circulation holes with different apertures, and the compression valves and the extension valves are respectively opened in the compression and extension processes of the shock absorber and are used for controlling the pressure of working fluid in the compression and extension processes;

a piston rod is fixed on the working piston, a control chamber is arranged on the piston rod, a stepping motor and a deflector rod are arranged in the control chamber, and the stepping motor controls the pretightening force control rotor and the flow control disc through the control rod;

2. The control method according to claim 1, wherein the bottom end of the control rod, the bottom end of the preload control rotor and the upper end of the flow control disc are provided with gear rings, the inner side and the outer side of the joint sleeve are respectively provided with teeth engaged with the gear ring at the bottom end of the control rod and teeth engaged with the gear ring at the bottom end of the preload control rotor and the gear ring at the upper end of the flow control disc, the inner side teeth of the joint sleeve are always engaged with the gear ring at the bottom end of the control rod, the two sides of the end parts of all the gear rings and the joint sleeve teeth are provided with reverse slopes to facilitate the joint of the joint sleeve and different gear rings, and the joint of the control rod and the preload control rotor.