CN115143224B - Magnetorheological damper with low zero-field damping force and wide damping adjustable range - Google Patents

Abstract

A magnetorheological damper with low zero-field damping force and wide damping adjustable range belongs to the technical field of vibration reduction systems. It includes a cylinder, a piston coaxially installed in the cylinder, two cylinder end covers removably installed at both ends of the cylinder and used to support the reciprocating motion of the piston, and a coil arranged in the middle of the outer wall of the piston; there is a coil in the middle of the piston. The raised part, the coil is installed on the raised part, the raised part separates the chamber of the cylinder into chamber Ⅰ and chamber Ⅱ, and the chamber Ⅰ and chamber Ⅱ are connected to the cylinder through the raised part The gaps between the inner walls are connected. The magnetorheological damper proposed by the present invention can provide smaller zero-field damping force. When the excitation coil is not energized, the magnetorheological fluid can flow freely in the two inner and outer annular throttling channels. Compared with the traditional single-channel magnetorheological damper, the cross-sectional area of the throttling channel is greatly increased, which can reduce The minimum damping force output value of the damper improves the vibration isolation effect under high-frequency excitation conditions.

Description

A magnetorheological damper with low zero-field damping force and wide damping adjustable range

Technical field

The invention belongs to the technical field of vibration reduction systems, and specifically relates to a magnetorheological damper.

Background technique

Magnetorheological fluid is a new type of smart material that is in a Newtonian fluid state when there is no magnetic field in the environment. When a magnetic field is applied to it, the magnetorheological fluid can transform from a Newtonian fluid state to a semi-solid state within milliseconds, and this change is reversible. The magnetorheological damper is a semi-active actuator designed based on this magnetorheological effect. It can adjust the output damping force by controlling the size of the excitation current. Compared with traditional hydraulic dampers, magnetorheological dampers have outstanding advantages such as continuously adjustable damping, high failure safety, and rapid response. Therefore, they have become a research hotspot in recent years and are widely used in vehicle suspensions, civil construction, and aviation. aerospace and other fields.

The adjustable range of damping force is a key indicator for evaluating the performance of magnetorheological dampers. Most of the existing magnetorheological damper structures increase the maximum output damping force of the magnetorheological damper by increasing the number of excitation coils, increasing the effective area of the magnetic field, and increasing the length of the throttling channel, thereby broadening the adjustable range of the damping force. the goal of. However, according to the linear vibration isolation theory, in the high-frequency vibration isolation zone, reducing the damping coefficient of the system is conducive to improving the vibration isolation performance of the system. Therefore, it is necessary to propose a zero-field damping force with a smaller zero-field damping force and a wider adjustable damping range. range of magnetorheological dampers.

The damping force output of the magnetorheological damper consists of three parts, namely viscous damping force, Coulomb damping force and friction force. The viscous damping force is the damping force caused by the viscosity of the magnetorheological fluid, which is an uncontrollable damping force. In order to reduce the zero-field damping force of the magnetorheological damper, this part of the damping force needs to be reduced. The Coulomb damping force is a damping force generated by the magnetorheological effect and is a controllable damping force. In order to increase the adjustable range of the damping force, this part of the damping force needs to be increased. Friction force mainly refers to the friction between the internal seals of the magnetorheological damper. This part is an uncontrollable damping force. In order to reduce the damping force caused by friction, the use of sliding seals needs to be minimized in the structural design.

Most of the existing magnetorheological dampers adopt a single annular throttling channel structure. According to the theory of fluid mechanics, it is known that in order to reduce the viscous damping force, the gap of the throttling channel needs to be increased. However, under the premise that the number of turns of the excitation coil is certain, the increase in the gap of the throttle channel will reduce the magnetic induction intensity inside the throttle channel, thereby reducing the Coulomb damping force and reducing the adjustable range of the damping force of the magnetorheological damper. . Therefore, it is difficult for traditional single-channel magnetorheological dampers to simultaneously achieve the two design goals of low zero-field damping and wide damping adjustable range.

After reviewing the literature, it was found that most of the existing dual-channel magnetorheological damper structures adopt a single coil structure. The magnetic field intensity in the two throttling channels is controlled by the same turn of excitation coil at the same time. The magnetic induction lines generated by the coils need to pass through the two vertically at the same time. The throttle channel gap greatly increases the magnetic resistance in the magnetic circuit. In order to ensure that the magnetic induction intensity in the throttling channel meets the requirements, it is necessary to increase the number of turns of the excitation coil. This causes the existing dual-channel magnetorheological damper to greatly increase the radial size and the piston area, thereby increasing the magnetic flow. Zero field damping force of variable damper.

In summary, in order to improve the vibration isolation performance of the magnetorheological damper, it is necessary to improve the existing magnetorheological damper structure and design a magnetorheological damper with low zero-field damping force and wide damping adjustable range. device. This is beneficial to improving the vibration isolation performance of magnetorheological dampers under high-frequency excitation and broadening the application scenarios of magnetorheological dampers.

Contents of the invention

In order to solve the problems mentioned in the background art, the present invention further provides a magnetorheological damper with low zero-field damping force and wide adjustable damping range.

The technical solution adopted by the present invention is: a magnetorheological damper with low zero-field damping force and wide damping adjustable range, including a cylinder body, a piston coaxially installed in the cylinder body, and a piston removably installed in the cylinder body. Two cylinder end covers are used to support the reciprocating motion of the piston, and a coil is provided in the middle of the outer wall of the piston; a raised portion is provided in the middle of the piston, and the coil is installed on the raised portion, and the raised portion connects the cylinder The chamber is divided into chamber I and chamber II, and chamber I and chamber II are connected through the gap between the protrusion and the inner wall of the cylinder.

Compared with the prior art, the present invention has the following beneficial effects:

1. Compared with existing magnetorheological dampers, the magnetorheological damper proposed in the present invention can provide smaller zero-field damping force. When the excitation coil is not energized, the magnetorheological fluid can flow freely in the two inner and outer annular throttling channels. Compared with the traditional single-channel magnetorheological damper, the cross-sectional area of the throttling channel is greatly increased, which can reduce The minimum damping force output value of the damper improves the vibration isolation effect under high-frequency excitation conditions.

2. The magnetorheological damper proposed by the present invention is equipped with a magnetic permeable ring and a magnetic isolating ring inside the two throttling channels. The design of the magnetic permeable ring and the magnetic isolating ring can greatly increase the effective coverage of the magnetic field under energized conditions. area, thereby increasing the maximum output damping force of the magnetorheological damper, which is beneficial to improving the vibration suppression effect of the magnetorheological damper in the low-frequency resonance area.

3. The magnetorheological damper proposed by the present invention has an impact overload protection function. When the current in the inner excitation coil is greater than the current in the outer excitation coil, the shear yield stress of the magnetorheological fluid in the inner throttling channel is greater. Under this working condition, when the piston moves at a low speed, the outer throttle channel is opened and the inner throttle channel is closed. When the magnetorheological damper is subject to impact excitation, the piston moves at a rapid rate. At this time, the piston in the outer throttle channel is The liquid flow rate increases sharply, causing the viscous pressure loss produced by the outer throttling channel to be greater than the Coulomb pressure loss produced by the inner throttling channel. At this time, the outer throttling channel and the inner throttling channel are opened at the same time, causing the liquid flow rate in the channel to significantly decrease. It can suppress the sharp increase of damping force, thereby reducing the force transmitted from impact excitation to the object being isolated, and realizing the impact overload protection function.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a schematic structural diagram of the piston end cover of the present invention;

Figure 3 is a schematic structural diagram of the cylinder end cover of the present invention;

Figure 4 is a schematic diagram of the ring magnetic pole structure of the present invention;

Figure 5 is a cross-sectional view along line A-A of Figure 4;

Figure 6 is a distribution diagram of magnetic field lines when the inner excitation coil of the present invention is energized;

Figure 7 is a magnetic field line distribution diagram when the outer excitation coil of the present invention is energized;

Figure 8 is a magnetic field line distribution diagram when the inner and outer excitation coils of the present invention are energized at the same time;

Among them: 1. Piston rod sealing ring; 2. Cylinder end cover; 3. Bolts; 4. Lead hole; 5. Piston end cover; 6. Ring magnetic pole; 7. Outside magnetic ring I; 8. Outside magnetic isolation Ring; 9. Outer magnetic ring II; 10. Outer excitation coil; 11. Inner excitation coil; 12. Screws; 13. Cylinder end cover sealing ring; 14. Chamber II; 15. Inner magnetic ring I; 16 , inner magnetic isolation ring Ⅰ; 17. inner magnetic conductive ring Ⅱ; 18. cylinder block; 19. chamber Ⅰ; 20. liquid injection hole; 21. piston rod; 22. annular groove; 23. arc-shaped through hole hole; 24, screw hole; 25, cylinder end cover wire groove; 26, bolt hole; 27, annular boss.

Detailed ways

In order to better understand the purpose, structure and function of the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Figure 1, a magnetorheological damper with low zero-field damping force and a wide damping adjustable range of the present invention includes a cylinder 18, a piston rod 21 coaxially installed in the cylinder 18, a removable Two cylinder end caps 2 are installed at both ends of the cylinder 18 and are used to support the reciprocating motion of the piston rod 21, and a coil is provided in the middle of the outer wall of the piston rod 21; a raised portion is provided in the middle of the piston rod 21, and the coil is installed on the raised portion On the top, the raised portion divides the chamber of the cylinder 18 into chamber I19 and chamber II14, and the chamber I19 and the chamber II14 are connected through the gap between the raised portion and the inner wall of the cylinder 18.

The magnetorheological fluid is in chamber I19 and chamber II14.

Among them: the coil is composed of an inner excitation coil 11 and an outer excitation coil 10;

The inner excitation coil 11 is wound in the winding groove provided on the boss portion of the piston rod 21, and the lead wire of the inner excitation coil 11 is led out through the lead hole 4 provided on the piston rod 21;

The outer excitation coil 10 is wound in the winding groove provided on the annular magnetic pole 6, and the lead wire of the outer excitation coil 10 is led out through the wire groove of the annular magnetic pole 6, the cylinder end cover wire groove 25 and the lead hole 4.

The annular magnetic pole 6 is set on the outside of the inner excitation coil 11, so that a gap is provided between the annular magnetic pole 6 and the inner excitation coil 11 to form an inner throttling channel, and the gap between the outer excitation coil 10 and the inner wall of the cylinder 18 forms an outer throttling channel. , the magnetorheological fluid in chamber I19 and chamber II14 can flow freely in the two internal and external throttling channels. Compared with the traditional single-channel magnetorheological damper, the cross-sectional area of the throttling channel is greatly increased, which can reduce the damping The minimum damping force output value of the device improves the vibration isolation effect under high-frequency excitation conditions.

And the annular magnetic pole 6 is clamped and fixed by the piston end caps 5 provided at both ends of the boss portion of the piston rod 21.

In addition, the magnetorheological damper also includes an inner magnetic conductive ring I15, an inner magnetic conductive ring II17, an inner magnetic isolating ring 16, an outer magnetic conductive ring I7, an outer magnetic conductive ring II9 and an outer magnetic isolating ring 8;

The inner magnetic conductive ring I15 and the inner magnetic conductive ring II17 are both sleeved on the outer surface of the convex part of the piston rod 21, and are clamped and fixed on the piston rod 21 through the two piston end caps 5. The inner magnetic isolating ring 16 is arranged on the inner guide. Between the magnetic ring I15 and the inner magnetic conductive ring II17, and set on the outer surface of the inner excitation coil 11;

The outer magnetic conductive ring I7 and the outer magnetic conductive ring II9 are both set on the outer surface of the annular magnetic pole 6, and are clamped and fixed on the piston rod 21 through the two piston end caps 5; the outer magnetic isolating ring 8 is arranged on the outer magnetic conductive ring Between I7 and the outer magnetic conductive ring II9, and set on the outer surface of the outer excitation coil 10;

The outer wall of the inner magnetic conductive ring I15, the outer wall of the inner magnetic isolating ring 16, the outer wall of the inner magnetic conductive ring II17 and the inner wall of the annular magnetic pole 6 form an inner throttling channel;

The outer walls of the outer magnetic conductive ring I7, the outer magnetic isolating ring 8, the outer magnetic conductive ring II9 and the inner wall of the cylinder 18 form an outer throttling channel.

The design of the magnetic conductive ring and the magnetic isolating ring can greatly increase the effective coverage area of the magnetic field under energized conditions, thereby increasing the maximum output damping force of the magnetorheological damper, which is beneficial to improving the suppression of the magnetorheological damper in the low-frequency resonance area. vibration effect.

Specifically: as shown in Figure 3,

The two piston rods 21 and the cylinder end cover 2 are sealed by a piston rod sealing ring 1 .

The end faces of the two cylinder end covers 2 are designed with six bolt holes 26 evenly distributed in the circumferential direction for installing bolts 3.

The two cylinder end covers 2 and the cylinder block 18 are connected by bolts 3, and a cylinder end cover sealing ring 13 is designed on the end face of the cylinder end cover 2 where it meets the cylinder block 18 to prevent the internal magnetism of the cylinder block 18. Rheological fluid overflow,

A liquid injection hole 20 is designed on the end face of the upper cylinder end cover 2 among the two cylinder end covers 2. After the assembly of the magnetorheological damper is completed, the magnetorheological fluid is injected from the liquid injection hole 20.

as shown in picture 2,

The two piston end caps 5 are respectively placed on the upper and lower sides of the raised portion of the piston rod 21, and are fixed on the piston rod 21 through screws 12.

A plurality of arc-shaped through holes 23 are evenly arranged on the end surfaces of the two piston end caps 5, preferably four, which are connected with the inner throttling channel for the conduction of the magnetorheological fluid.

A plurality of screw holes 24 are evenly provided on the end surfaces of the two piston end caps 5 for installing screws 12 .

An annular groove 22 is provided on the end surfaces of the two piston end caps 5 , which cooperates with an annular boss 27 provided on the outer wall of the annular magnetic pole 6 for positioning and clamping the annular magnetic pole 6 .

A radial cylinder end cover wire groove 25 is provided on the end surface of the upper piston end cover 5 for leading out the wires of the outer excitation coil 10 .

As shown in Figure 4 and Figure 5,

The annular magnetic pole 6 is designed with a winding groove on the outer circumferential surface for drawing out the wires of the outer excitation coil 10; annular bosses 27 are designed at both ends of the annular magnetic pole 6, and the annular boss 27 is in contact with the The annular grooves 22 on the two piston end caps 5 cooperate to position the annular magnetic poles 6 .

The cylinder end cover 2, piston end cover 5, inner magnetic isolation ring 16, and outer magnetic isolation ring 8 are all made of non-magnetic conductive materials; the remaining parts are made of magnetically conductive materials.

The working principle of the present invention is as follows:

When neither the inner excitation coil 11 nor the outer excitation coil 10 is energized, there is no magnetic field in the inner throttling channel and the outer throttling channel. When the piston rod 21 moves, the magnetorheological fluid in the chamber I19 and the chamber II14 will pass through. When the inner throttle channel and the outer throttle channel flow, due to the viscosity of the liquid, a pressure difference will occur on both end surfaces of the piston rod 21, thereby generating a damping force.

When the inner excitation coil 11 is energized and the outer excitation coil 10 is de-energized, the distribution of magnetic flux lines inside the magnetorheological damper is shown in Figure 6 . At this time, a magnetic field is generated in the inner throttling channel that passes vertically through the channel, but there is no magnetic field inside the outer throttling channel. The shear yield stress of the magnetorheological fluid in the inner throttling channel is significantly increased by the magnetic field. When the piston rod 21 moves at low speed, the magnetorheological fluid only flows through the outer throttling channel. At this time, increasing the excitation current of the inner excitation coil 11 has no effect on the damping force output value; when the piston rod 21 is subject to impact-type excitation, the piston rod 21 The increase in moving speed leads to an increase in the flow rate of the magnetorheological fluid, which in turn leads to a significant increase in the viscous pressure drop generated by the outer throttle channel. When the viscous pressure drop generated by the outer throttle channel is greater than the Coulomb pressure drop of the inner throttle channel , the magnetorheological fluid in the inner throttling channel begins to flow. At this time, the flow rate of the magnetorheological fluid in the channel is greatly reduced compared with when only the outer throttling channel flows. This can suppress the sudden increase in damping force and reduce the impact type excitation work. The force transfer rate under the condition.

When the inner excitation coil 11 is de-energized and the outer excitation coil 10 is energized, the distribution of magnetic flux lines inside the magnetorheological damper is shown in Figure 7 . At this time, a magnetic field is generated in the outer throttling channel that passes vertically through the channel, but there is no magnetic field inside the inner throttling channel. The shear yield stress of the magnetorheological fluid in the outer throttling channel is significantly increased by the magnetic field. At this time, the magnetorheological fluid only flows in the inner throttling channel under low-speed conditions. When the moving speed of the piston rod 21 increases, the magnetorheological fluid in the inner throttling channel and the outer throttling channel flows simultaneously, which can suppress the impact type. The sudden increase in damping force under excitation conditions reduces the force transfer rate under impact-type excitation conditions.

When the inner excitation coil 11 and the outer excitation coil 10 are energized at the same time, the magnetic flux line distribution inside the magnetorheological damper is as shown in Figure 8. At this time, magnetic fields vertically passing through the channels are generated in both the inner throttle channel and the outer throttle channel, and the damping force output by the magnetorheological damper is the largest at this time.

It is understood that the present invention has been described through some embodiments. Those skilled in the art know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, the features and embodiments may be modified to adapt a particular situation and material to the teachings of the invention without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the present application are within the scope of protection of the present invention.

Claims (6)

1. A magnetorheological damper with low zero-field damping force and wide adjustable damping range, characterized by: including a cylinder (18) and a piston rod (21) coaxially installed in the cylinder (18) , two cylinder end covers (2) removably installed at both ends of the cylinder (18) and used to support the reciprocating motion of the piston rod (21), and a coil provided in the middle of the outer wall of the piston rod (21); the piston rod (21) 21) There is a raised part in the middle, and the coil is installed on the raised part. The raised part divides the chamber of the cylinder (18) into chamber I (19) and chamber II (14), and the chamber The connection between I (19) and chamber II (14) is through the gap between the protrusion and the inner wall of the cylinder (18). The coil is composed of an inner excitation coil (11) and an outer excitation coil (10); The inner excitation coil (11) is wound in the winding groove provided on the boss portion of the piston rod (21), The outer excitation coil (10) is wound in a winding groove provided on the annular magnetic pole (6), and the annular magnetic pole (6) is sleeved on the outside of the inner excitation coil (11), so that the annular magnetic pole (6) A gap is provided between the outer excitation coil (11) and the inner excitation coil (11) to form an inner throttling channel. The gap between the outer excitation coil (10) and the inner wall of the cylinder (18) constitutes an outer throttling channel. Chamber I (19) and the chamber The magnetorheological fluid in chamber II (14) can flow freely in the two internal and external throttling channels, and the annular magnetic pole (6) is clamped by the piston end caps (5) provided at both ends of the boss portion of the piston rod (21) fixed, The magnetorheological damper with low zero-field damping force and wide damping adjustable range also includes an inner magnetic conductive ring I (15), an inner magnetic conductive ring II (17), an inner magnetic isolating ring (16), an outer conductive ring Magnetic ring I (7), outer magnetic conductive ring II (9) and outer magnetic isolating ring (8); The inner magnetic conductive ring I (15) and the inner magnetic conductive ring II (17) are both sleeved on the outer surface of the raised part of the piston rod (21), and are clamped by the two piston end caps (5). The magnetic isolation ring (16) is arranged between the inner magnetic conductive ring I (15) and the inner magnetic conductive ring II (17), and is set on the outer surface of the inner excitation coil (11); The outer magnetic conductive ring I (7) and the outer magnetic conductive ring II (9) are both set on the outer surface of the circular magnetic pole (6), and are clamped by two piston end caps (5); the outer magnetically isolated ring The ring (8) is arranged between the outer magnetic conductive ring I (7) and the outer magnetic conductive ring II (9), and is set on the outer surface of the outer excitation coil (10); The outer wall of the inner magnetic conductive ring I (15), the outer wall of the inner magnetic isolating ring (16), the outer wall of the inner magnetic conductive ring II (17) and the inner wall of the circular magnetic pole (6) form an inner throttling channel; The outer walls of the outer magnetic conductive ring I (7), the outer magnetic isolating ring (8), the outer magnetic conductive ring II (9) and the inner wall of the cylinder (18) form an outer throttling channel. 2. A magnetorheological damper with low zero-field damping force and wide adjustable damping range according to claim 1, characterized in that: the two cylinder end covers (2) and the cylinder (18) ) are connected by bolts (3), and a cylinder end cover sealing ring (13) is designed on the end face of the cylinder end cover (2) where it meets the cylinder block (18) to prevent the internal magnetism of the cylinder block (18). The rheological fluid overflows, and a liquid injection hole (20) is designed on the end face of the upper cylinder end cover (2) of the two cylinder end covers (2). After the magnetorheological damper is assembled, the magnetic The rheological fluid is injected from the injection hole (20). 3. A magnetorheological damper with low zero-field damping force and wide adjustable damping range according to claim 2, characterized in that: the two piston end caps (5) are respectively set on the piston rod ( 21), and are fixed to the piston rod (21) by screws (12). A plurality of arc-shaped through holes (23) are evenly distributed on the end surfaces of the two piston end covers (5), and are connected to the inner side of the piston rod (21). The throttling channel is connected for the conduction of magnetorheological fluid. A plurality of screw holes (24) are evenly provided on the end surfaces of the two piston end covers (5) for installing screws (12). 4. A magnetorheological damper with low zero-field damping force and wide adjustable damping range according to claim 3, characterized in that: a ring-shaped ring is provided on the end surfaces of the two piston end caps (5). The groove (22) cooperates with the annular boss (27) provided on the outer wall of the annular magnetic pole (6), and is used for positioning and clamping the annular magnetic pole (6). 5. A magnetorheological damper with low zero-field damping force and wide adjustable damping range according to claim 4, characterized in that: a radial The wire groove (25) of the cylinder end cover is used to lead out the wires of the outer excitation coil (10). 6. A magnetorheological damper with low zero-field damping force and wide adjustable damping range according to claim 5, characterized in that: the lead of the inner excitation coil (11) passes through the piston rod (21) The lead hole (4) provided on the top leads out; The lead wire of the outer excitation coil (10) is led out through the wire groove of the annular magnetic pole (6), the cylinder end cover wire groove (25) and the wire lead hole (4).