CN112161017B - Quick response magneto-rheological damper - Google Patents

Abstract

The invention discloses a quick-response magnetorheological damper, which comprises a piston, an excitation coil, magnetorheological fluid, a piston rod, an outer cylinder barrel, an end cover, a floating piston, a guide ring and the like. The outer surface of the piston and the inner surface of the outer cylinder barrel are provided with grooves which are uniformly distributed in the radial direction and are used for inhibiting eddy current which is excited by the change of a magnetic field in a magnetic circuit; the electromagnetic coil is wound on the piston; one end of the piston rod is connected with the piston, the other end of the piston rod is connected with the external load, magnetorheological fluid is filled in the outer cylinder barrel, a damping channel is formed between the outer cylinder barrel and the piston, and the magnetorheological fluid flows between the two cavities through the damping channel. The invention relates to a magneto-rheological damper, which is characterized in that the magnetic field establishment time of the magneto-rheological damper is a key factor influencing the quick response performance of a device, and the formation of eddy current under a dynamic magnetic field is inhibited from the aspect of prolonging a skin-seeking path based on the requirement on the quick response performance of the magneto-rheological damper, namely, a groove is arranged on the surface of a related structure to inhibit an eddy current field, so that the aim of reducing the magnetic field establishment time is fulfilled, and the magneto-rheological damper has excellent quick response performance.

Description

A fast-response magnetorheological damper

technical field

The invention relates to a variable damping control device, in particular to a fast-response magnetorheological damper.

Background technique

Magnetorheological dampers have excellent magnetron damping characteristics, and their advantages such as simple mechanical structure, wide dynamic range, low power consumption, large output damping force, and short response time make them widely concerned in the field of shock buffering. It has huge application prospects in the fields of bridges, automobiles and aerospace. The dynamic response performance of the magnetorheological damper is characterized by the response time. The shorter the response time, the better the real-time control. There are few studies on fast response performance. The response time of magnetorheological dampers is mainly composed of magnetorheological fluid response time, magnetic field establishment time, circuit response time, etc. Among them, reducing the magnetic field establishment time is the key to reducing the response time of the device, and the main factor that causes the magnetic field establishment time to be longer. It is the dynamic magnetic field corresponding to the rapidly changing signal of the excitation coil that excites eddy currents on the surface of the piston and other structures, forming a reverse magnetic field to hinder the establishment of the source magnetic field, delaying the response of the magnetorheological fluid to the excitation signal, and showing that the output damping force cannot respond quickly. . Therefore, suppressing eddy currents is the key to reducing the response time. However, the piston of the existing magnetorheological damper generally adopts a complete cylindrical structure. When the magnetic field changes, a large eddy current will be generated on the surface of the piston, which hinders the change of the magnetic field and reduces the response speed.

SUMMARY OF THE INVENTION

The technical problem to be solved by the embodiments of the present invention is to provide a fast-response magnetorheological damper. Fast-response magnetorheological dampers.

In order to solve the above technical problems, an embodiment of the present invention provides a fast-response magnetorheological damper, including a lower end cover, a floating piston, an excitation coil, a piston rod, an outer cylinder, an upper end cover, a lower end cover of the piston, a guide ring, a piston , the upper end cover of the piston, the magnetorheological fluid, the two ends of the outer cylinder are closed by the upper end cover and the lower end cover to form a accommodating cavity, the piston rod passes through the upper end cover, and the piston is machined with radial grooves The excitation coil is wound around the groove, and the excitation coil leads out the wire through the through hole provided by the piston rod; the guide ring is coaxial with the piston, and is assembled on the upper end cover of the piston and the Between the lower end caps of the piston, the upper end cap of the piston and the lower end cap of the piston both have liquid flow holes; the floating piston and the piston are sequentially slidingly arranged in the accommodating cavity to form a compensation cavity, a first magnetorheological fluid cavity, The first magnetorheological fluid chamber, the magnetorheological fluid is filled in the first magnetorheological fluid chamber and the first magnetorheological fluid chamber.

Wherein, the inner surface of the guide ring and the outer circular surfaces of the two wings of the piston form a damping channel gap.

Wherein, the groove communicates with the upper and lower end surfaces and the outer circular surface of the piston.

Implementing the embodiment of the present invention has the following beneficial effects:

1. Fast response. Because the invention sets radially uniform grooves on the outer circular surface of the piston and the inner circular surface of the outer cylinder, the skin path of the eddy current is extended, and according to Ohm's law, it is equivalent to increasing the resistance, which reduces the eddy current and suppresses The suppression of the eddy current field means that the weakening effect on the source magnetic field is reduced, and the magnetic flux acting on the damping channel is increased, which ensures the fast response of the damper. It is verified by finite element simulation that the eddy current generated by the grooved magnetorheological damper is one order of magnitude lower than that of the traditional non-groove magnetorheological damper, and the response time is reduced by 35.85% under the excitation of the step rising edge. Response time decreased by 53.54%. The quick-response magnetorheological damper of the present invention is especially suitable for the occasions where the response speed of the vibration damping device is high, such as automobile suspension and aircraft landing gear.

2. Simple structure and material saving. The quick-response magnetorheological damper of the present invention is based on the single-rod magnetorheological damper in structural design, and radially evenly distributed grooves are arranged on the outer circular surface of the piston and the inner circular surface of the outer cylinder, and the structure is simple Reliable, the piston is manufactured with additive materials, and due to the existence of grooves, it saves material compared with traditional dampers, which is more economical and practical.

Description of drawings

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

Figure 2 is a front view of a grooved piston;

Figure 3 is a top view of a grooved piston;

Figure 4 is a sectional view of a grooved piston;

5 is a partial view of a fast-response magnetorheological damper at an electromagnetic piston;

Figure 6 is a top view of the upper end cover of the piston;

Fig. 7 is this example step rising edge excitation diagram;

Fig. 8 is the step falling edge excitation diagram of this example;

Fig. 9 is the comparison of the response time under the excitation of the step rising edge of this example and the traditional magnetorheological damper, the dotted line is the fast-response magnetorheological damper, and the dotted line is the traditional magnetorheological damper;

Figure 10 shows the comparison between the response time of the example under the step falling edge excitation and the traditional magnetorheological damper, the dotted line is the fast-response magnetorheological damper, and the dotted line is the traditional magnetorheological damper.

The accompanying notes are as follows:

1—lower end cover; 2—protective gas; 3—floating piston; 4—first magnetorheological fluid chamber; 5—excitation coil; 6—piston rod; 7—outer cylinder; 8—second magnetorheological fluid chamber ;9—upper end cover; 10—compensation chamber; 11—piston lower end cover; 12—guide ring; 13—piston; 14—piston upper end cover; 15—magnetorheological fluid; 16—piston center through hole; 17—groove ; 18—wire axial blind hole; 19—wire radial hole; 20—electromagnetic piston; 21—liquid flow hole; 22—damping channel.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, a quick-response magnetorheological damper according to an embodiment of the present invention includes a lower end cover 1, a floating piston 3, an excitation coil 5, a piston rod 6, an outer cylinder 7, an upper end cover 9, and a lower piston end cover 11. , Guide ring 12 , piston 13 , piston upper end cap 14 , magnetorheological fluid 15 .

The electromagnetic piston 20 is composed of the piston 13 , the excitation coil 5 , the piston rod 6 , the piston upper end cover 14 , the piston lower end cover 11 , the guide ring 12 , and the like.

Both ends of the outer cylinder 7 are closed by the upper end cover 9 and the lower end cover 1 to form a accommodating cavity, in which a circular hole is machined in the center of the upper end cover, through which the piston rod passes; the piston is machined with radial grooves 17, and the center is machined through. Hole 16, winding the excitation coil 5 in the middle, as shown in Figure 2-4.

As shown in Fig. 5, the guide ring 12 is coaxial with the piston 13, and is assembled between the upper end cover 14 of the piston and the lower end cover 11 of the piston. The inner measurement and the outer circular surface of the side wing of the piston maintain a certain distance to form a damping channel 22. The magnetorheological fluid 15 flows in from the liquid flow hole 21 of the piston end cover, and flows out through the damping channel 22 . The upper end cover 14 of the piston and the lower end cover 11 of the piston are processed with uniformly distributed liquid flow holes 21 in the circumferential direction, which are coaxially and coplanarly matched with the upper and lower end surfaces of the piston, as shown in FIG. 6 .

The piston rod 6 passes through the central through hole 16 of the piston and has an interference fit with the through hole. When an external load acts on one end of the piston rod 6, the piston rod and the piston move together, and the resistance of the piston also acts on the outside of the other end of the piston rod 6. On the load, the transmission of motion and force is realized.

When the excitation coil 5 is energized, the piston 13, the magnetorheological fluid 15, and the outer cylinder 7 form a magnetic circuit. The magnetic flux is generated by the excitation coil 5 in the middle of the piston, transmitted to the side of the piston through the core of the piston 13, passes through the damping channel filled with the magnetorheological fluid 15, enters the outer cylinder 7, and then passes through the damping channel by the outer cylinder 7 22. Return to the core through the other flank of the piston.

The inner surface of the outer cylinder barrel 7 is processed with radially evenly distributed grooves, and the two ends are assembled with the upper end cover 9 and the lower end cover 1 to form a closed cavity, which is divided into three cavities by the floating piston 3 and the electromagnetic piston 20. The lower end cover Between 1 and the floating piston 3 is the compensation chamber 10, between the floating piston 3 and the electromagnetic piston 20 is the first magnetorheological fluid chamber 4, the electromagnetic piston 20 and the upper end cover 9 are the second magnetorheological fluid chamber 8, and the upper end cover 9. The floating piston 3 and the lower end cover 1 are installed with sealing rings for sealing. The upper end cover 14 of the piston, the guide ring 12 and the lower end cover 11 of the piston at the electromagnetic piston 20 are all closely matched with the inner wall of the outer cylinder 7, leaving a damping channel 22 for communication The first magnetorheological fluid chamber 4 and the second magnetorheological fluid chamber 8 . The compensation chamber 10 is filled with protective gas 2 for compensating for the pressure difference caused by the existence of the piston rod 6 in the second magnetorheological fluid chamber 8 when the damper operates.

The working process of the present invention is as follows:

Referring to Figure 7, Figure 8. When the excitation coil 5 is not energized, if the piston rod 6 moves towards the lower end cap under the action of the load, the magnetorheological fluid in the first magnetorheological fluid chamber 4 is compressed and flows through the damping channel 22 of the electromagnetic piston 20 to the lower end cap. The second magnetorheological fluid chamber. At this time, there is no magnetic field in the damping channel 22, the magnetorheological fluid 15 can be regarded as a Newtonian fluid, and the damping force generated by the movement of the piston is very small; if the excitation coil 5 is energized at this time, it is equivalent to applying a step rise to the magnetorheological damper 7, the source magnetic field excited by the excitation coil 5, the magnetorheological fluid 15 at the damping channel 22, under the action of the magnetic field, the ferromagnetic particles form a chain-like structure along the magnetic line of force, changing from Newtonian fluid. It is a solid-like body, which increases the damping force on the electromagnetic piston 20, and the damping force is transmitted to the external load through the piston rod 6 to complete the response to loads such as vibration; The source magnetic field gradually weakens to disappear, and the magnetorheological fluid in the damping channel 22 changes from a solid-like to a Newtonian fluid again due to the weakening of the magnetic field, and the piston damping force decrease.

The quick response principle of the present invention is as follows:

The piston 13 and the outer cylinder 7 of the fast-response magnetorheological damper are provided with radially evenly distributed grooves 17. When the excitation coil is energized, that is, a step rising edge current excitation is applied to the magnetorheological damper. In the groove damper, the magnetic flux is transmitted to the piston flank through the piston core, which is bound to excite the eddy current field on the surface of the piston. In turn, the response of the damping force becomes slower; and for the grooved magnetorheological damper of the present invention, according to the skin effect of the eddy current, grooves are set to divide the piston surface, which prolongs the adhesion path. According to Ohm's law, the adhesion path The extension is equivalent to increasing the resistance, which reduces the eddy current, the reverse induced magnetic field of the eddy current is weakened, the source magnetic field is quickly established in the damping channel, the damping force responds quickly, and the performance of fast response is realized; when the excitation coil is powered off, the When the magnetorheological damper is excited by a step falling edge current, for a traditional non-groove damper, the magnetic field suddenly decreases and an eddy current is excited on the surface of the piston. The eddy current induces a reverse magnetic field to prevent the magnetic field from weakening, thereby making the magnetic field at the damping channel It cannot disappear quickly, that is, the speed at which the magnetorheological fluid recovers from a solid-like fluid to a Newtonian fluid becomes slower, resulting in a slower response to the damping force; while for the grooved magnetorheological damper of the present invention, the groove makes the eddy current excited by the magnetic field change greatly. If it is weakened, the magnetic field at the damping channel can quickly subside, and the magnetorheological fluid can quickly become a Newtonian fluid after the excitation coil is powered off, which increases the response speed of the damping force.

Referring to Fig. 9 and Fig. 10 , the finite element simulation of the magnetorheological damper is performed in ANSYS Maxwell, and its response time is calculated. The results show that the grooves of the piston and the outer cylinder greatly enhance the fast response performance of the magnetorheological damper. It is reduced by 35.85% and 53.54%. After simulation verification, its eddy current is one order of magnitude lower than that of the traditional magnetorheological damper.

Optionally, in this embodiment, the number of grooves is set to 108, the liquid flow holes of the upper and lower end caps of the piston are set to 4, the upper and lower end caps and the outer cylinder are closed by welding, and the rising edge and falling edge of the piston are stepped. The peak value of the edge current is 2A, and the response time is less than 1ms, see Figure 7 and Figure 8.

What is disclosed above is only a preferred embodiment of the present invention, and of course it cannot limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims (1)

1. A quick-response magnetorheological damper, characterized in that it comprises a lower end cap, a floating piston, an excitation coil, a piston rod, an outer cylinder, an upper end cap, a lower end cap of the piston, a guide ring, a piston, an upper end cap of the piston, a magnetic Rheological fluid, both ends of the outer cylinder are closed by the upper end cover and the lower end cover to form a accommodating cavity, the piston rod passes through the upper end cover, and the inner surface of the guide ring and the outer circular surfaces of the two piston wings form a damping channel The piston and the outer cylinder are both machined with radially evenly distributed grooves to reduce eddy currents, so that the source magnetic field can be quickly established in the damping channel, and the damping force responds quickly, and the grooves communicate with the The upper and lower end faces of the piston and the outer circular surface, the number of the grooves is set to 108, the piston is wound with the excitation coil, and the excitation coil leads out the wire through the through hole provided by the piston rod; the The guide ring is coaxial with the piston, and is assembled between the upper end cover of the piston and the lower end cover of the piston. The upper end cover of the piston and the lower end cover of the piston both have liquid flow holes; the floating piston and the piston are sequentially slidingly arranged on In the accommodating chamber, a compensation chamber, a first magnetorheological fluid chamber, and a second magnetorheological fluid chamber are formed, and the magnetorheological fluid is filled in the first magnetorheological fluid chamber and the second magnetorheological fluid chamber. in the cavity.

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