CN104534012B - The MR damper that working clearance is variable and parameter optimization method thereof - Google Patents

Abstract

A magnetorheological damper with variable working gap and a parameter optimization method thereof belong to the technical field of magnetorheological dampers. The magnetorheological damper is characterized in that: the piston cylinder is composed of an outer cylinder (1) and an inner cylinder (8); the outer wall of the inner cylinder (8) is attached to the inner surface of the outer cylinder (1), and the inner wall and the piston (2) form Working gap; there are multiple inner cylinders (8), each of which has the same height and outer diameter and different thicknesses, and the inner cylinders (8) of different thicknesses are replaced to change the working clearance of the magneto-rheological damper. The present invention changes the working gap between the outer cylinder and the piston by replacing the inner cylinder with different thicknesses, so that the damping force of the damper can be varied in a wide range, realizing a damper with output in various ranges and saving costs. Simple and reliable, with great practicality.

Description

Magneto-rheological damper with variable working gap and its parameter optimization method

technical field

The invention relates to the technical field of magnetorheological dampers, in particular to a magnetorheological damper with variable working gap and a parameter optimization method thereof.

Background technique

The magnetorheological damper is a new type of structural semi-active control device that has emerged in the past ten years. Among them, the shear valve magnetorheological damper has the characteristics of simple structure and convenient magnetic circuit design. It usually adopts the structure of piston and cylinder, and its working principle can be described as: when the piston and cylinder move relative to each other, it will squeeze the MR fluid on one side of the piston in the cylinder to make it flow to the cylinder piston through the gap the other side of the When a magnetic field perpendicular to the flow direction of the fluid is applied to both sides of the gap, due to the "solidification" of the magnetorheological fluid in the gap, when the MR fluid passes through, the "solidified" magnetorheological fluid in the gap must produce viscoplastic flow, Thereby a corresponding damping force is generated.

According to the Bingham model of magnetorheological fluid and fluid mechanics, the pseudostatic model of damping force of shear valve magnetorheological damper is:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;\&eta;Dl</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; \&eta;l</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&pi;D</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&pi;Dl</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}\mathrm{<span\; class="notranslate">\; sgn</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; l</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}$

Among them: τ _y is the shear stress of the magnetorheological fluid, which is related to the external magnetic field; η is the zero-field viscosity of the magnetorheological fluid, sgn is the sign function, l is the effective length of the piston, v is the moving speed of the piston, D is the diameter of the piston, d is the diameter of the piston rod; Ap is the area of the piston, and F _f is the seal friction force, h is the damper gap width.

The output range of the shear valve magnetorheological damper will be fixed after the structural design is completed, and the output range is related to the structural parameters of the damper. Among them, the size of the gap between the outer cylinder and the piston has a great influence on the output of the magnetorheological damper. If the gap is too small, the maximum damping force of the magnetorheological damper is large, but the minimum damping force is also large; if the gap is too large , the minimum damping force of the magnetorheological damper is small, but the maximum damping force will be reduced. A magneto-rheological damper that changes the working gap by replacing the inner cylinder can effectively solve this problem and has great practical value.

Contents of the invention

The invention solves the problem and adopts the technical solution: Since the working gap of the ordinary magnetorheological damper is fixed, the damping force range of the damping force is fixed and cannot be changed in a wide range, which limits the use of the damper. The invention patent is a magnetorheological damper with variable working gap. By changing the inner cylinder with different thickness and changing the working gap between the outer cylinder and the piston, the damping force of the damper can be varied in a wide range, realizing A damper has output in multiple ranges, saves cost, is simple and reliable, and has great practicability. The invention also includes the design method of the inner cylinder, how to reasonably determine the number and size of the inner cylinder according to the maximum damping force and the pseudo-static model, so that the variable range of the damping force of the damper can be reasonably expanded by replacing the inner cylinder.

The invention comprises a piston barrel, a first end cap and a second end cap respectively installed at two ends of the piston barrel, a piston rod installed in the piston barrel and protruding from the first end cap and the second end cap; the piston rod is installed with a piston , a coil is wound on the piston, a wire hole is provided on the piston and the piston rod, and the wire of the coil is drawn out from the wire hole; the piston barrel is filled with magnetorheological fluid; the first end cap or the second end cap is respectively provided with a sealing ring, and The first end cover is provided with a leakage hole closed by a leakage screw;

The above-mentioned piston cylinder is composed of an outer cylinder and an inner cylinder;

The outer wall of the inner cylinder is attached to the inner surface of the outer cylinder, and the inner wall and the piston form a working gap; there are multiple inner cylinders, the height and outer diameter of each inner cylinder are the same, and the thickness is different. Replace the inner cylinder with different thickness to change the magnetorheological damper working gap.

The design method of the replaceable magneto-rheological damper of the inner cylinder:

Given the main structural parameters of the magnetorheological damper, including: the inner diameter of the outer cylinder D, the diameter of the piston rod d, the yield strength τ of the magnetorheological fluid under magnetic field saturation, the yield strength τ ₀ of the MRF zero magnetic field, and the MRF zero-field viscosity η , working speed v, piston effective length l, seal friction force F _f ;

The calculation model of the damping force of the shear valve magnetorheological damper is expressed as:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;\&eta;Dl</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; \&eta;l</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&pi;D</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&pi;Dl</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}\mathrm{<span\; class="notranslate">\; sgn</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; l</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}$

Among them: τ _y is the shear stress of the magnetorheological fluid, which is related to the external magnetic field; η is the zero-field viscosity of the magnetorheological fluid, sgn is the sign function, l is the effective length of the piston, v is the moving speed of the piston, D is the piston diameter, d is the piston rod diameter, Ap is the piston area, and F _f is the seal friction force, h is the damper gap width;

Substituting the main structural parameters of the given magnetorheological damper into the output model of the shear valve magnetorheological damper to calculate the output range of the damper, only changing the value of the working gap h, and keeping other parameters unchanged, calculate the output of the damper Range; because too small h will block the working gap, the initial value of h is 1mm;

When the working gap h is greater than a certain value, the change of the minimum damping force of the damper will be very small, and this value is taken as the maximum working gap; the maximum working gap is divided into multiple sections, and the division is based on the density of the output range change. The inner diameter of the inner cylinder is the outer diameter corresponding to each working gap, and the outer diameter of the inner cylinder is the inner diameter of the outer cylinder.

The beneficial effect of the invention is that the working gap of the magneto-rheological damper can be changed by replacing the inner cylinder of the magneto-rheological damper, thereby realizing the variable output range of the damper. When the maximum damping force is required to be large, the inner cylinder with a small inner diameter is used, and when the minimum damping force is required to be small, the inner cylinder with a large inner diameter is replaced, which avoids the use of different types of magneto-rheological dampers and saves costs.

Description of drawings

Accompanying drawing 1 is the overall structure schematic diagram of magnetorheological damper;

The structural representation of accompanying drawing 2 inner barrel;

Label names in the figure: 1. Outer cylinder, 2. Piston, 3. Piston rod, 4A. First end cover, 4B. Second end cover, 5. Coil, 6. Magnetorheological fluid, 7. Leakage screw, 8. Inner cylinder, 9A. First sealing ring, 9B. Second sealing ring.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiments of the present invention, as shown in Figure 1:

The present invention comprises a piston barrel, a first end cap 4A and a second end cap 4B installed at both ends of the piston barrel respectively, a piston rod 3 installed in the piston barrel and stretching out the first end cap 4A and the second end cap 4B; the piston A piston 2 is installed on the rod 3, a coil 5 is wound on the piston 2, a wire hole is arranged on the piston 2 and the piston rod 3, and the wire of the coil 5 is drawn out from the wire hole; the piston barrel is filled with a magnetorheological fluid 6; the first end The cover 4A or the second end cover 4B are respectively provided with a sealing ring 9A and a sealing ring 9B, and the first end cover 9A is provided with a leaking hole closed by a leaking screw 7;

Above-mentioned piston cylinder is made up of outer cylinder 1 and inner cylinder 8;

The outer wall of the inner cylinder 8 is attached to the inner surface of the outer cylinder 1, and the inner wall and the piston 2 form a working gap; there are multiple inner cylinders 8, and each inner cylinder 8 has the same height, outer diameter, and different thickness. Replace the inner cylinder 8 with a different thickness. Change the working gap of the magnetorheological damper.

Specific design examples:

instance 1;

The structural parameters of a certain type of damper except h are initially determined as follows:

The calculation model of the damping force of the shear valve magnetorheological damper is expressed as:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;\&eta;Dl</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; \&eta;l</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&pi;D</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&pi;Dl</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}\mathrm{<span\; class="notranslate">\; sgn</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; l</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}$

where τ is the shear stress of the MR fluid, and τy is the yield stress of the MR fluid, which is related to the applied magnetic field. η is the plastic viscosity of the MR fluid, γ is the shear strain rate of the MR fluid, and sgn is the sign function. l is the effective length of the piston, the diameter of the piston is D, v is the moving speed of the piston, the diameter of the piston rod is d, and the gap width of the damper is h.

Substituting the initial parameters into the calculation model of the damping force of the shear valve magnetorheological damper, the range of damping force at different gaps can be obtained:

The gap of the damper is 1mm, the maximum damping force is 6000N, and the minimum damping force is 431N;

The gap of the damper is 2mm, the maximum damping force is 3148N, and the minimum damping force is 233N;

The gap of the damper is 3mm, the maximum damping force is 2200N, and the minimum damping force is 187N;

The gap of the damper is 4mm, the maximum damping force is 1739N, and the minimum damping force is 167N;

It can be seen that when the working gap is greater than 3 mm, the minimum value of the damping force does not change significantly, so the total thickness of the working gap is positioned at 3 mm. Divide 3mm into 3 layers, 1mm, 2mm, and 3mm, and need to process two specifications of sleeves.

The inner diameter of the inner cylinder 1 is: 42mm and the outer diameter is: 46mm

The inner diameter of the inner cylinder 2 is: 44mm and the outer diameter is: 46mm

When using No. 1 inner cylinder, the working gap is 1mm, the maximum damping force is 6000N, and the minimum damping force is 431N

When the No. 2 inner cylinder is used, the gap becomes 2mm, the maximum damping force is 3148N, and the minimum damping force is 233N

When the inner cylinder is not used, the gap becomes 3mm, the maximum damping force is 2200N, and the minimum damping force is 187N

It can be seen that this design method can achieve the effect of changing the output range of the damper by replacing different sleeves.

Example 2:

The structural parameters of a certain type of damper except h are initially determined as follows:

Substituting the initial parameters into the calculation model of the damping force of the shear valve magnetorheological damper, the range of damping force at different gaps can be obtained:

The gap of the damper is 1mm, the maximum damping force is 24280N, and the minimum damping force is 2000N;

The gap of the damper is 1.5mm, the maximum damping force is 16000N, and the minimum damping force is 1060N;

The gap of the damper is 2mm, the maximum damping force is 12100N, and the minimum damping force is 745N;

The gap of the damper is 3mm, the maximum damping force is 8278N, and the minimum damping force is 509N;

The gap of the damper is 4mm, the maximum damping force is 6382N, and the minimum damping force is 413N;

It can be seen that when the working gap is greater than 3mm, the minimum value of the damping force does not change significantly, so the total thickness of the working gap is positioned at 3mm. Divide 3mm into 3 layers, 1mm, 1.5mm, 3mm, and need to process two specifications of sleeves.

The inner diameter of the inner cylinder 1 is: 42mm and the outer diameter is: 46mm

The inner diameter of the inner cylinder 2 is: 43mm and the outer diameter is: 46mm

When using No. 1 inner cylinder, the working gap is 1mm, the maximum damping force is 24280N, and the minimum damping force is 2000N

When the No. 2 inner cylinder is used, the gap becomes 1.5mm, the maximum damping force is 16000N, and the minimum damping force is 1060N

When the inner cylinder is not used, the gap becomes 3mm, the maximum damping force is 8278N, and the minimum damping force is 509N. It can be seen that this design method can achieve the effect of changing the output range of the damper by replacing different sleeves.

Claims (2)

1. the MR damper that the working clearance is variable,

Comprise piston barrel, the first end cap (4A) and the 2nd end cap (4B) being installed on piston barrel two ends respectively, is installed in piston barrel and stretches out the first end cap (4A) and the piston rod (3) of the 2nd end cap (4B); Piston rod (3) is provided with piston (2), piston (2) is wound with coil (5), being provided with wire hole on piston (2) and piston rod (3), the wire of coil (5) is drawn from wire hole; Filling magnetic flow liquid (6) in piston barrel; First end cap (4A) is provided with the first sealing-ring (9A), 2nd end cap (4B) is provided with the 2nd sealing-ring (9B), and the first end cap (4A) is provided with the liquid-leaking nozzle closed with leakage screw (7);

It is characterized in that:

Above-mentioned piston barrel is made up of urceolus (1) and interior cylinder (8);

Interior cylinder (8) outer wall is fitted in the internal surface of urceolus (1), and inwall and piston (2) form the working clearance; Interior cylinder (8) has multiple, the height of cylinder (8) in each, and external diameter is identical, and thickness is different, and the interior cylinder (8) changing different thickness is to change the working clearance of MR damper.

2. the parameter optimization method of the MR damper that the working clearance according to claim 1 is variable, it is characterised in that comprise following process:

The main structure parameters of given MR damper, comprising: urceolus (1) internal diameter D; Piston rod (3) diameter d, the yield strength �� under magnetic flow liquid magnetic field is saturated, MRF zero magnetic field lower yield strength ��₀, MRF zero viscosity ��, working speed v, piston (2) useful length l, seal friction power F_f;

Shearing valve type magneto-rheological deoscillator damping force computation model represents:

Wherein: ��_yIt is the shear-stress of magnetic flow liquid, relevant with externally-applied magnetic field; �� is zero viscosity of magnetic flow liquid, sgn is-symbol function, and l is the useful length of piston, and v is the movement velocity of piston, and D is piston diameter, and d is piston rod diameter; Ap is piston area, andF_fFor seal friction power, h is deoscillator gap width;

The model of exerting oneself that the main structure parameters of given MR damper substitutes into shearing valve type magneto-rheological deoscillator calculates the scope of exerting oneself of deoscillator, only changes the numerical value of working clearance h, other parameter constants, calculates the scope of exerting oneself of deoscillator; Owing to excessively little h can make the working clearance block, the value of initial h gets 1mm;

When working clearance h is big and during certain value, the change of the minimum damping force of deoscillator will be very little, and getting this value is maximum functional gap; Maximum functional gap is divided into multistage, partitioning standards be exert oneself scope change density degree, the internal diameter of interior cylinder is the external diameter corresponding to every period of working clearance, and the external diameter of interior cylinder is the internal diameter of urceolus.