Magnetorheological dampers with buffering function and their buffering control methods

Abstract

This invention provides a magnetorheological damper with buffering function and its buffering control method. The magnetorheological damper includes a piston rod, a cylinder, a sealing seat, a piston, and a floating piston. One end of the cylinder is open, and the sealing seat is fixedly connected to the open end of the cylinder. The piston is slidably disposed inside the cylinder. One end of the piston rod is connected to the piston, and the other end of the piston rod extends through the sealing seat to the outside of the cylinder. An excitation coil is wound around the outer circumference of the piston. The floating piston is slidably disposed inside the cylinder, located between the piston and the bottom surface of the cylinder. The inner diameter of the cylinder at the middle position is larger than the inner diameters on both sides of the cylinder. This invention can solve the problems of limited adjustable range of existing magnetorheological dampers, the inability to simultaneously achieve maximum and minimum damping forces, and the resulting bottoming-out and top-out problems of magnetorheological suspensions under adverse road conditions.

Description

Technical Field

[0001] This invention relates to the field of suspension damping technology, specifically to a magnetorheological damper with buffering function and its buffering control method. Background Technology

[0002] Magnetorheological suspension has broad application prospects due to its simple structure, semi-active adjustable damping force, and rapid response. Magnetorheological suspension typically uses air springs as the elastic element and magnetorheological dampers as the damping element.

[0003] During the operation of a magnetorheological suspension, semi-active control of the suspension is achieved by changing the current in the magnetorheological damper. To achieve better comfort, the magnetorheological damper used in magnetorheological suspensions must possess a very small zero-field damping force. To meet this requirement, the width of the working flow channel of the magnetorheological damper needs to be increased, thereby reducing the impact of the magnetorheological fluid's throttling effect on the zero-field damping force.

[0004] However, the adjustable range of magnetorheological dampers is limited. Increasing the width of the working channel reduces the zero-field damping force, but it also reduces the maximum damping force of the magnetorheological damper. In other words, the maximum and minimum forces of the magnetorheological damper cannot be simultaneously achieved. When road conditions are poor (e.g., on or off bridges, on potholes), the magnetorheological suspension may experience bottoming out or top-hitting problems due to insufficient maximum force from the magnetorheological damper, severely reducing the comfort of the magnetorheological suspension.

[0005] In view of this, the inventors of this application have designed a magnetorheological damper with buffering function and its buffering control method in order to overcome the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the problem that the adjustable range of the magnetorheological damper in the prior art is limited, and the maximum damping force and minimum damping force cannot be taken into account at the same time, and the resulting problem of bottoming out and top contact of the magnetorheological suspension when the road conditions are bad. The present invention provides a magnetorheological damper with buffering function and its buffering control method.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] This invention provides a magnetorheological damper with a buffering function, characterized in that the magnetorheological damper includes a piston rod, a cylinder, a sealing seat, a piston, and a floating piston; one end of the cylinder is open, and the sealing seat is fixedly connected to the open end of the cylinder; the piston is slidably disposed inside the cylinder; one end of the piston rod is connected to the piston, and the other end of the piston rod extends through the sealing seat to the outside of the cylinder; an excitation coil is wound around the outer periphery of the piston; the floating piston is slidably disposed inside the cylinder, located between the piston and the bottom surface of the cylinder; the inner diameter of the cylinder at its middle position is larger than the inner diameters of the cylinder's two sides.

[0009] According to one or more embodiments of the present invention, a working flow channel is formed between the piston and the sidewall of the cylinder; the region with a larger inner diameter in the middle of the cylinder is a damping zone, the working flow channel formed by the piston and the sidewall of the damping zone cylinder has a larger width, and the piston experiences a smaller damping force when sliding in the damping zone; the regions with smaller inner diameters on both sides of the cylinder are buffer zones, the working flow channel formed by the piston and the sidewall of the buffer zone cylinder has a smaller width, and the piston experiences a larger damping force when sliding in the buffer zone.

[0010] According to one or more embodiments of the present invention, an inclination angle is provided between the region with a larger inner diameter in the middle of the cylinder and the regions with smaller inner diameters on both sides of the cylinder to form a transition zone.

[0011] According to one or more embodiments of the present invention, magnetorheological fluid is filled between the lower end face of the sealing seat and the upper end face of the floating piston in the cylinder; gas is filled between the lower end face of the floating piston and the bottom surface of the cylinder to form a gas chamber in the cylinder, and a gas flow channel is provided on the bottom surface of the cylinder.

[0012] According to one or more embodiments of the present invention, a recovery chamber is formed between the piston and the sealing seat, and a compression chamber is formed between the piston and the floating piston. The recovery chamber and the compression chamber are connected through the working flow channel. When the piston slides in a direction close to the sealing seat, the magnetorheological fluid in the recovery chamber is squeezed and enters the compression chamber through the working flow channel. When the piston slides in a direction close to the bottom surface of the cylinder, the magnetorheological fluid in the compression chamber is squeezed and enters the recovery chamber through the working flow channel. The volume change caused by the piston rod connected to the piston entering and exiting the cylinder is compensated by the gas chamber.

[0013] According to one or more embodiments of the present invention, the piston includes an iron core, which constitutes the body of the piston. The iron core is provided with a winding groove and a lead groove for winding and leading of the excitation coil.

[0014] According to one or more embodiments of the present invention, the magnetorheological vibration damper satisfies the following design formula: ;in, F Indicates damping force; L This is the piston length; The average perimeter of the working flow channel; A p The effective area of ​​the iron core; η The dynamic viscosity of the fluid; u τ is the velocity of the iron core relative to the cylinder; τ is the shear yield strength of the magnetorheological fluid. h This refers to the width of the working flow channel.

[0015] According to one or more embodiments of the present invention, the magnetorheological damper with buffering function is applied to a suspension structure; the working channel width of the vibration reduction zone is... h 1 The buffer flow channel width is h 2 , h 1 >h 2 Let the maximum piston displacement under rated operating conditions be S. max The length L1 of the damping zone satisfies the following formula: Where L is the piston length; the length L2 of the buffer zone satisfies the following formula: ;in, M This refers to the upper suspension mechanism and the total load mass. v The relative speed between the upper and lower ends of the suspension; F max This is the maximum output damping force of the buffer zone.

[0016] According to one or more embodiments of the present invention, the working flow channel width of the vibration damping zone h 1 =1.2mm, buffer zone working channel width h 2 =0.8mm, damping zone length L1=55mm, buffer zone length L2=5mm, transition zone inclination angle is 30°.

[0017] According to one or more embodiments of the present invention, the excitation coil is electrically or communicatively connected to the displacement sensor, and the current of the excitation coil is controlled according to the real-time detection data of the displacement sensor.

[0018] This invention also provides a buffer control method for a magnetorheological damper with a buffer function. The method is characterized in that it is applied to the magnetorheological damper with a buffer function as described above. The buffer control method includes the following steps: S1, a displacement sensor collects the relative displacement between the upper and lower suspension layers to obtain the piston displacement of the magnetorheological damper with a buffer function; S2, a displacement threshold is set. When the piston displacement is less than or equal to the threshold, the piston remains in the damping zone, and the magnetorheological damper with a buffer function is under rated operating conditions. At this time, the current of the excitation coil is controlled by an intelligent control algorithm. When the piston displacement is greater than the threshold, the piston's extreme position begins to exceed the damping zone and enter the buffer zone. The magnetorheological damper with a buffer function is under extreme operating conditions, and the current of the excitation coil is increased.

[0019] According to one or more embodiments of the present invention, the steps prior to step S1 include the following steps: S0, based on the mechanical performance test results of the magnetorheological damper prototype with buffer function, the values ​​of each parameter in the model of the excitation coil under different currents are identified respectively, and then the relationship between each parameter and the current is fitted to obtain the mechanical model of the magnetorheological damper with buffer function.

[0020] According to one or more embodiments of the present invention, in step S0, the mechanical model of the magnetorheological damper with buffering function is expressed as follows: The inverse model of this mechanical model is represented as: Where F represents the damping force; x This indicates the relative displacement of the piston; x ' is the first derivative of displacement with respect to time, which represents the velocity of the piston; I represents the current in the excitation coil.

[0021] According to one or more embodiments of the present invention, in step S1, the relative displacement between the upper and lower layers of the suspension... ;in, x s This represents the displacement of the upper suspension layer. x x Let S be the displacement of the lower suspension layer; the piston displacement S is calculated using a function relating it to the relative displacement Δx between the upper and lower suspension layers. This function is expressed as: When the suspension is in the equilibrium position, the iron core is exactly located in the center of the damping zone, and the displacement of the iron core is S=0.

[0022] According to one or more embodiments of the present invention, in step S2, the displacement threshold is set to S. max / 2, when At this time, the magnetorheological damper with buffer function is under rated operating conditions. At this time, the current I of the excitation coil is controlled by an intelligent control algorithm. The expression of the intelligent control algorithm is as follows: ; ;in, The damping force required for suspension vibration reduction is calculated using an intelligent control algorithm; This is the maximum output of the magnetorheological power; The damping coefficient; x s This represents the displacement of the upper suspension layer. x x This represents the displacement of the lower suspension layer. x This indicates the relative displacement of the piston; x ' is the first derivative of displacement with respect to time, which represents the velocity of the piston; I represents the current in the excitation coil; when At this time, the magnetorheological damper with buffer function is under extreme operating conditions. At this time, the current I of the excitation coil is increased so that I = I max .

[0023] The positive and progressive effects of this invention are as follows:

[0024] This invention, a magnetorheological damper with buffering function and its buffering control method, solves the technical problem of limited adjustable range and the inability to simultaneously achieve maximum and minimum damping forces in existing magnetorheological dampers. By changing the cylinder inner diameter, this invention provides different maximum and minimum damping forces at different positions in the stroke. Compared to ordinary magnetorheological dampers, this invention's buffering-function magnetorheological damper better meets the actual needs of magnetorheological suspension vibration reduction, effectively resolving the conflict between comfort and bottoming / top contact in magnetorheological suspension. Furthermore, the implementation of this buffering-function magnetorheological damper is simple and does not increase costs compared to ordinary magnetorheological dampers. Attached Figure Description

[0025] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0026] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the magnetorheological damper with buffering function of the present invention.

[0027] Figure 2 This is a schematic diagram illustrating the buffering function principle of the magnetorheological damper with buffering function of the present invention.

[0028] Figure 3 This is a schematic diagram of the force-displacement curve of a common magnetorheological damper.

[0029] Figure 4This is a schematic diagram of the force-displacement curve of the magnetorheological damper with buffering function of the present invention.

[0030] Figure 5a This is a cross-sectional schematic diagram of the cylinder structure of the magnetorheological damper with buffering function of the present invention.

[0031] Figure 5b This is a three-dimensional schematic diagram of the cylinder structure of the magnetorheological damper with buffering function of the present invention.

[0032] Figure 6a This is a three-dimensional schematic diagram of the core structure of the magnetorheological damper with buffering function of the present invention.

[0033] Figure 6b This is a cross-sectional schematic diagram of the core structure of the magnetorheological damper with buffering function of the present invention.

[0034] Figure 7 This is a schematic diagram illustrating the principle of the buffer control method for the magnetorheological damper with buffer function of the present invention.

[0035] Figure 8 This is a three-dimensional schematic diagram of the overall structure of the magnetorheological damper with buffering function of the present invention.

[0036] [Attached image labels]

[0037] 100. Piston rod

[0038] 110. Upper connector

[0039] 120. Plug

[0040] 200. Cylinder

[0041] 210. Bottom surface of the cylinder barrel

[0042] 211. Gas flow channel

[0043] 220. Lower connector

[0044] 221. Check valve

[0045] 230. O-ring assembly chamfer.

[0046] 240. Inclination angle of the transition zone of the restoration cavity

[0047] 250°, Inclination angle of the transition zone of the compression chamber

[0048] 260. Chamfering of welded joints

[0049] 300. Sealing seat

[0050] 310. Sealing components

[0051] 320. Sealing seat O-ring

[0052] 330. Guide support components

[0053] 340. Dustproof parts

[0054] 400, Piston

[0055] 410. Excitation coil

[0056] 411. Magnetic circuit

[0057] 420. Iron core

[0058] 421. Winding groove

[0059] 422. Lead wire groove

[0060] 500, Floating Piston

[0061] 510. Floating piston O-ring

[0062] 520, guide belt

[0063] 610. Air chamber

[0064] 620. Restoration cavity

[0065] 630. Compression Chamber

[0066] 640. Workflow

[0067] 650, Vibration Reduction Zone

[0068] 660, Buffer Zone

[0069] 661. Restoration cavity buffer zone

[0070] 662. Compression Chamber Buffer Zone

[0071] 670. Transition Zone

[0072] 671. Transition zone of the restoration cavity

[0073] 672. Compression Chamber Transition Zone

[0074] 700, Displacement Sensor

[0075] 800, Suspension Elastic Elements Detailed Implementation

[0076] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0077] Reference will now be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts. Furthermore, although the terminology used herein is selected from commonly known and used terms, some terms mentioned in this specification may have been chosen by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of the description herein. Moreover, the invention should be understood not only by the actual terminology used, but also by the meaning implied by each term. Also, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0078] See Figure 1 , Figure 2 Figure 5- Figure 8 The present invention provides a magnetorheological damper with a buffer function, the magnetorheological damper comprising a piston rod 100, a cylinder 200, a sealing seat 300, a piston 400, and a floating piston 500.

[0079] One end of the cylinder 200 is open, and the sealing seat 300 is fixedly connected to the open end of the cylinder 200;

[0080] The piston 400 is slidably disposed inside the cylinder 200; one end of the piston rod 100 is connected to the piston 400, and the other end of the piston rod 100 extends through the sealing seat 300 to the outside of the cylinder 200; an excitation coil 410 is wound around the outer periphery of the piston 400.

[0081] The floating piston 500 is slidably disposed inside the cylinder 200, located between the piston 400 and the bottom surface 210 of the cylinder 200.

[0082] The inner diameter of the middle part of cylinder 200 is larger than the inner diameter of the two sides of cylinder 200.

[0083] It should be noted that the excitation coil 410 is wound around the outer periphery of the piston 400. When energized, it can generate an excitation magnetic field. The piston 400 preferably includes an iron core 420 to enhance the excitation magnetic field. The excitation magnetic field will change the viscosity of the fluid inside the cylinder 200, thereby generating different magnitudes of damping force on the piston 400. The fluid inside the cylinder 200 is preferably a magnetorheological fluid. The damping force of the magnetorheological damper can be controlled by adjusting the current.

[0084] It should be noted that when the piston 400 moves to different inner diameters of the cylinder 200, the internal fluid flows through the gap between the piston 400 and the cylinder 200. In the large inner diameter section in the middle of the cylinder 200, the fluid flow cross-sectional area is large, the flow resistance is small, and the damping force is small. When the piston 400 moves to the small inner diameter sections on both sides of the cylinder 200, the fluid flow cross-sectional area decreases, the flow velocity increases, and a throttling effect is formed, thereby generating greater flow resistance (damping force). This magnetorheological damper structure of this application realizes automatic damping adjustment of the piston 400 at different positions through the natural change of the inner diameter of the cylinder, which is beneficial to the end buffering of the damper.

[0085] Preferably, an upper connector 110 is fixed to the end of the piston rod 100, and a lower connector 220 is fixed to the bottom end of the cylinder 200. The inner surface of the lower connector 220 forms the bottom surface 210 of the cylinder 200.

[0086] The magnetorheological damper with buffer function of this invention can solve the problems of limited adjustable range of existing magnetorheological dampers, the inability to simultaneously achieve maximum and minimum damping forces, and the resulting bottoming-out and top-out problems of magnetorheological suspension when road conditions are poor.

[0087] See Figure 1 , Figure 2 , Figure 5a and Figure 5b In a preferred embodiment of the magnetorheological damper with buffering function of the present invention, a working flow channel 640 is formed between the piston 400 and the cylinder 200.

[0088] The area with a larger inner diameter in the middle of the cylinder 200 is the damping zone 650. The working flow channel 640 formed by the piston 400 and the side wall of the cylinder 200 damping zone 650 is relatively wide, and the damping force experienced by the piston 400 when sliding in the damping zone 650 is relatively small.

[0089] The smaller inner diameter areas on both sides of cylinder 200 form buffer zones 660. The working flow channel 640 formed by piston 400 and the side wall of cylinder 200 in buffer zone 660 has a smaller width, and piston 400 experiences a larger damping force when sliding in buffer zone 660.

[0090] It should be noted that by changing the inner diameter of the cylinder 200, the magnetorheological damper can achieve different maximum and minimum damping forces at different positions of its stroke. In the middle of the cylinder 200, the inner diameter is larger (mid-stroke), and the width of the annular working channel 640 formed with the iron core 420 is also larger. Therefore, the damping force generated by the throttling effect of the magnetorheological fluid at zero field is very small, and the magnetorheological damper, which has a buffering function, has a very small zero-field damping force. At the left and right ends of the cylinder 200, the inner diameter is smaller (stroke limit positions), and the width of the annular working channel 640 formed with the iron core 420 is also smaller. At this point, when a large current is applied, the magnetorheological damper has a larger maximum damping force, thus providing a buffering effect.

[0091] See Figure 1 , Figure 2 , Figure 5a and Figure 5b In a preferred embodiment of the magnetorheological damper with buffering function of the present invention, an inclination angle is set between the region with a larger inner diameter in the middle of the cylinder 200 and the regions with smaller inner diameter on both sides of the cylinder 200 to form a transition zone 670.

[0092] The inclination angle of the transition zone of the restoration cavity is 240°, and the inclination angle of the transition zone of the compression cavity is 250°. Figure 5a As shown.

[0093] It should be noted that, to avoid sudden changes in the output force of the magnetorheological damper due to drastic changes in the inner diameter of cylinder 200, which could cause impact, a transition angle is added between different inner diameters of cylinder 200. See [link / reference] Figure 1 and Figure 2 In a preferred embodiment of the magnetorheological damper with buffering function of the present invention, magnetorheological fluid is filled between the lower end face of the sealing seat 300 and the upper end face of the floating piston 500 in the cylinder 200; gas is filled between the lower end face of the floating piston 500 and the bottom surface 210 of the cylinder 200 to form a gas chamber 610, and a gas flow channel 211 is provided on the bottom surface 210 of the cylinder 200, through which high-pressure gas can be injected into the gas chamber 610.

[0094] See Figure 1 and Figure 2 In a preferred embodiment of the magnetorheological damper with buffering function of the present invention, a recovery cavity 620 is formed between the piston 400 and the sealing seat 300, and a compression cavity 630 is formed between the piston 400 and the floating piston 500. The recovery cavity 620 and the compression cavity 630 are connected through a working flow channel 640.

[0095] When the piston 400 slides in the direction close to the sealing seat 300, the magnetorheological fluid in the restoration chamber 620 is squeezed and enters the compression chamber 630 through the working flow channel 640.

[0096] When the piston 400 slides along the direction close to the bottom surface of the cylinder 200, the magnetorheological fluid in the compression chamber 630 is squeezed and enters the recovery chamber 620 through the working flow channel 640.

[0097] The volume change caused by the piston rod 100, which is connected to the piston 400, entering and exiting the cylinder 200 is compensated by the air chamber 610.

[0098] Preferably, the annular gap formed between the cylinder 200 and the piston 400 serves as the annular working channel 640 of the magnetorheological damper. When the magnetorheological fluid flows through the working channel 640, it generates a magnetorheological effect under the action of the excitation magnetic field, and the viscosity of the magnetorheological fluid changes accordingly. The stronger the excitation magnetic field, the greater the viscosity and the greater the magnetorheological damping force.

[0099] See Figure 6a and Figure 6b As a preferred embodiment of the magnetorheological damper with buffer function of the present invention, the piston 400 includes an iron core 420, which constitutes the main body of the piston 400. The iron core 420 is provided with a winding groove 421 and a lead groove 422 for winding and leading of the excitation coil 410.

[0100] Preferably, both the cylinder 200 and the iron core 420 are made of ferromagnetic materials with good magnetic permeability. The excitation magnetic field forms a closed magnetic circuit 411 between the iron core 420, the annular working channel 640, and the cylinder 200.

[0101] A specific embodiment of the magnetorheological damper with buffering function of the present invention is as follows:

[0102] like Figure 1As shown, the upper connector 110 and piston rod 100 of the magnetorheological damper with buffer function of the present invention are connected by threads. The piston rod 100 passes through the sealing seat 300 and is inserted into the cylinder 200, and is connected and fixed to the iron core 420 of the piston 400 by threads. The sealing element 310, dustproof element 340, and guide support element 330, which are provided inside the sealing seat 300, achieve dynamic sealing, guidance, and support for the piston rod 100 entering and exiting the cylinder 200. The iron core 420 is provided with a winding groove 421 and a lead wire groove 422 (as shown in Figure 6). The lead wire of the excitation coil 410 is led out from the piston rod 100 through the lead wire groove 422 and the plug 120. The plug 120 is made of silicone rubber, and the sealing of the plug 120 prevents the magnetorheological fluid from leaking from the piston rod 100. The sealing seat 300 is connected to the cylinder 200 by threads. To prevent the magnetorheological fluid inside the cylinder 200 from leaking out through the thread gaps, a sealing seat O-ring 320 is provided on the sealing seat 300. Additionally, to prevent damage to the sealing seat O-ring 320, an O-ring assembly chamfer 230 is provided on the left side of the cylinder 200 (as shown in Figure 5). A guide band 520 is provided on the floating piston 500, which provides support and guidance during the floating piston 500's up-and-down movement. Furthermore, a floating piston O-ring 510 is also provided on the floating piston 500, serving a sealing function to prevent the magnetorheological fluid from entering the air chamber 610 at the bottom of the floating piston 500. The lower connector 220 is fixed to the cylinder 200 by welding. To prevent welding leakage, a welding interface chamfer 260 is provided on the cylinder 200 (as shown in Figure 5). A one-way valve 221 is installed on the lower connector 220 to supply gas to the air chamber 610 (…). Figure 2 (As shown) Inflate.

[0103] like Figure 2 As shown, the iron core 420 and the floating piston 500 divide the internal space of the cylinder 200 into different chambers. The chamber between the iron core 420 and the sealing seat 300 is the recovery chamber 620, the chamber between the iron core 420 and the floating piston 500 is the compression chamber 630, and the chamber between the floating piston 500 and the lower connector 220 is the air chamber 610. The recovery chamber 620 and the compression chamber 630 are connected by an annular working channel 640. When the damper performs the recovery movement (i.e., the piston rod 100 extends), the magnetorheological fluid in the recovery chamber 620 is compressed and enters the compression chamber 630 through the working channel 640; when the damper performs the compression movement (i.e., the piston rod 100 retracts), the magnetorheological fluid in the compression chamber 630 is compressed and enters the recovery chamber 620 through the working channel 640. The volume change caused by the piston rod 100 entering the cylinder 200 is compensated by the air chamber 610.

[0104] like Figure 2As shown, the magnetorheological damper's stroke is divided into different intervals because the inner diameter of the cylinder 200 varies at different positions, resulting in different effective flow channel widths. The middle section is the damping zone 650, where the working flow channel 640 formed by the core 420 and the cylinder 200 is relatively wide, resulting in a very small minimum output force. The left and right sides, near the tensile and compressive limits of the stroke, are the recovery chamber buffer zone 661 and the compression chamber buffer zone 662, respectively. The working flow channel 640 formed by the core 420 and the cylinder 200 in this area is narrower, allowing for a larger maximum damping force when a large current is applied, thus providing a buffering effect. To prevent a sudden change in the magnetorheological damper's output force when transitioning from the damping zone 650 to the buffer zone 660, causing an impact, the inner diameters of the cylinder 200 in the buffer zone 660 and damping zone 650 are transitioned by an inclination angle, forming a transition zone 670 to achieve a smooth transition of the magnetorheological damping force.

[0105] The inclination angle of the transition zone of the restoration cavity is 240°, and the inclination angle of the transition zone of the compression cavity is 250°. Figure 5a As shown.

[0106] Figure 3 The diagram shows the force-displacement curve of a conventional magnetorheological damper, which is approximately rectangular in shape. Figure 4 The diagram shows the force-displacement curve of the magnetorheological damper with buffer function of this invention. At the extreme positions on both sides, the output force of the magnetorheological damper increases rapidly due to the reduction in the width of the working channel 640. In magnetorheological suspension vibration reduction, if a conventional magnetorheological damper is used, the contradiction between comfort and bottoming out / top contact requires consideration of both comfort and bottoming out / top contact issues when setting the width of the working channel 640 of the magnetorheological damper, thus limiting further improvement in the comfort of the magnetorheological suspension. However, if a magnetorheological damper with buffer function is used, a larger working channel 640 width can be set in the damping zone 650, thereby further improving the comfort of the magnetorheological suspension. Furthermore, when road conditions are poor, the presence of the buffer zone 660 can also prevent bottoming out and top contact issues.

[0107] As a preferred embodiment of the magnetorheological damper with buffering function of the present invention, the magnetorheological damper satisfies the following design formula:

[0108]

[0109] in, F Indicates damping force; L The piston is 400mm long; The average perimeter of the working flow channel is 640. A p This represents the effective area of ​​the 420 iron core. η The dynamic viscosity of the fluid; uτ is the velocity of the iron core 420 relative to the cylinder 200; τ is the shear yield strength of the magnetorheological fluid. h The width of the working flow channel is 640.

[0110] In the above formula, the first term is independent of the magnetic induction intensity and is the throttling damping force component of the output damping force of the magnetorheological damper; the second term is the Coulomb force component affected by the magnetic induction intensity.

[0111] The minimum force of the magnetorheological damper with buffering function in this invention refers to the output force of the magnetorheological damper when the current in the excitation coil 410 is 0. When the current is 0, the magnetic induction intensity is 0, and τ is very small. Therefore, the minimum force of the magnetorheological damper is mainly affected by the throttling damping force. The throttling damping force is related to the width of the working flow channel 640. h 3 Negative correlation, achieved by setting a larger effective working flow channel width of 640 in the vibration reduction zone 650. h This ensures a smaller minimum damping force in the 650 damping zone (due to 3) LA p / h As the term decreases, the maximum damping force of the magnetorheological damper will also decrease to some extent.

[0112] The maximum force of the magnetorheological damper with buffer function in this invention refers to the output force of the magnetorheological damper when the excitation coil 410 carries the maximum current. When the current reaches its maximum, the magnetic induction intensity reaches its maximum, and τ also reaches its maximum. This is achieved by setting a smaller working flow channel 640 width in the buffer zone 660. h This can rapidly increase the throttling damping force, and the 3% of the Coulomb force... LA p / h The increase in size, combined with the effect of both, results in a greater maximum damping force in the buffer zone 660.

[0113] The conventional magnetorheological damper has a working flow channel width of 640 throughout its entire stroke. h To maintain consistency, the magnetorheological damper with buffering function is configured by setting the working flow channel 640 of the damping zone 650 to a width of [missing information]. h 1 >h The buffer zone has a working flow channel width of 640. h 2 <h It is more suitable for applications such as suspension damping.

[0114] As a preferred embodiment of the magnetorheological damper with buffering function of the present invention, the magnetorheological damper with buffering function is applied to a suspension structure;

[0115] The vibration damping zone 650 working flow channel 640 width ish 1 The working channel 640 of buffer 660 has a width of h 2 , h 1 >h 2 ;

[0116] Let the maximum displacement of the piston at 400° under rated operating conditions be S. max The length L1 of the 650mm damping zone satisfies the following formula:

[0117]

[0118] Where L is the length of piston 400;

[0119] The length L2 of buffer 660 satisfies the following formula:

[0120]

[0121] in, M This refers to the upper suspension mechanism and the total load mass. v The relative speed between the upper and lower ends of the suspension; F max This is the maximum output damping force of the buffer zone 660.

[0122] The maximum value S of the piston displacement at 400° under the above-assuming rated operating conditions. max , can be the maximum displacement of the suspension damping magnetorheological damping piston 400 under normal road conditions. In order to ensure that the magnetorheological damping piston 400 with buffer function under normal road conditions always works in the damping zone 650, the length L1 of the damping zone 650 must satisfy the above formula (2).

[0123] To prevent the suspension from bottoming out and hitting the top, the magnetorheological damper with buffer function should have a sufficiently strong energy dissipation capacity in the buffer zone 660. Therefore, the length L2 of the buffer zone 660 must satisfy the above formula (3).

[0124] The transition zone 670 of the magnetorheological damper with buffer function is mainly to prevent the output force of the piston 400 from changing abruptly when it enters the buffer zone 660 from the damping zone 650. The smaller angle of the transition zone 670 can achieve a smooth transition of the damping force between the damping zone 650 and the buffer zone 660.

[0125] As a preferred embodiment of the magnetorheological damper with buffering function of the present invention, the vibration reduction zone 650 and the working flow channel 640 are respectively... h 1 =1.2mm, buffer zone 660, working flow channel 640 width h 2=0.8mm, the length of the damping zone 650 L1=55mm, the length of the buffer zone 660 L2=5mm, and the tilt angle of the transition zone 670 is 30°.

[0126] It should be noted that the above preferred settings can be applied to the vibration isolation conditions of seat suspension, and the values ​​are selected based on the test results of seat suspension samples.

[0127] See Figure 7 In a preferred embodiment of the magnetorheological damper with buffer function of the present invention, the excitation coil 410 is electrically or communicatively connected to the displacement sensor 700, and the current of the excitation coil 410 is controlled according to the real-time detection data of the displacement sensor 700.

[0128] Figure 7 In this invention, a magnetorheological damper with buffering function is installed at position A of the suspension, and a suspension elastic element 800 is also provided on the suspension.

[0129] It should be noted that the position of the iron core 420 relative to the cylinder 200 is calculated by real-time detection data through the external displacement sensor 700. When the iron core 420 enters the area with a smaller inner diameter at the left or right end of the cylinder 200, a large current is applied to the excitation coil 410 for buffer control, thereby avoiding the suspension from bottoming out or hitting the top.

[0130] like Figure 7 As shown, the magnetorheological damper with buffering function of this invention is positioned at location A. First, the stroke of the magnetorheological damper is calculated based on the suspension travel and its geometric parameters. Then, the stroke of the magnetorheological damper is divided into a damping zone 650, a transition zone 670, and a buffer zone 660. When the suspension is in equilibrium, the core 420 of the magnetorheological damper with buffering function is located in the damping zone 650. During the operation of the magnetorheological suspension, the height change of the suspension is collected in real time by the displacement sensor 700, and the position of the magnetorheological damper core 420 is calculated based on the geometric parameters. Under normal road conditions, during the movement of the magnetorheological suspension, the iron core 420 of the magnetorheological damper is mainly located in the damping zone 650. At this time, intelligent control algorithms can be used to control the suspension. Under severe road conditions, the displacement sensor 700 detects the movement height of the suspension. When it is detected that the suspension is about to bottom out or top out when it reaches the limit of its travel, the iron core 420 moves to the buffer zone 660 to apply a large current to the magnetorheological damper with buffering function, thereby avoiding the bottoming out and top out problems of the suspension.

[0131] The present invention also provides a buffer control method for a magnetorheological damper with buffering function, wherein the buffer control method is applied to the magnetorheological damper with buffering function as described above, and the buffer control method for the magnetorheological damper with buffering function includes the following steps:

[0132] Step S0: Based on the mechanical performance test results of the magnetorheological damper prototype with buffer function, identify the values ​​of each parameter in the model of the excitation coil 410 under different currents, and then fit the relationship between each parameter and the current to obtain the mechanical model of the magnetorheological damper with buffer function.

[0133] In step S0, the model of the magnetorheological damper with buffering function can first be established based on the mechanical performance test results of the prototype magnetorheological damper with buffering function, using existing magnetorheological damper models such as hyperbolic tangent model or polynomial model. Taking the hyperbolic tangent model as an example:

[0134]

[0135] in, c 0 The damping coefficient; k 0 The damping coefficient; α This is the hysteresis loop proportionality coefficient; f 0 The biasing force generated by the actuator, measured in N; β This is the proportionality coefficient of the hysteresis loop slope; δ The width of the hysteresis loop.

[0136] Based on the mechanical performance test results of the prototype, the values ​​of each parameter in the model under different currents I were identified. Then, the relationship between each parameter and the current was fitted to obtain the mechanical model of the magnetorheological damper with buffering function of this invention. The expression of the mechanical model is as follows:

[0137]

[0138] The inverse model of this mechanical model is represented as:

[0139]

[0140] Where F represents the damping force; x This indicates the relative displacement of piston 400; x ' is the first derivative of displacement with respect to time, which represents the velocity of piston 400; I represents the current of excitation coil 410.

[0141] Step S1: Displacement sensor 700 collects the relative displacement between the upper and lower layers of the suspension to obtain the displacement of piston 400 of magnetorheological damper with buffer function.

[0142] Preferably, in step S1, as follows: Figure 7 As shown, the displacement sensor 700 collects the relative displacement between the upper and lower layers of the suspension. ;in, x s This represents the displacement of the upper suspension layer. x x This represents the displacement of the lower layer of the suspension.

[0143] When the suspension moves up and down, it drives the magnetorheological damper core 420, which has a buffering function, to move. The displacement of the piston 400, S, has a fixed functional relationship with Δx. S can be converted into a function relationship with the relative displacement Δx between the upper and lower layers of the suspension. The functional relationship is expressed as:

[0144]

[0145] When the suspension is in the equilibrium position, the iron core 420 is exactly located at the center of the damping zone 650, and the displacement of the iron core 420 is S=0.

[0146] The specific functional expression of the above formula (7) is determined by the geometric relationship between the suspension mechanisms.

[0147] Step S2: Set the displacement threshold. When the displacement of piston 400 is less than or equal to the threshold, piston 400 is always located in the damping zone 650. The magnetorheological damper with buffer function is in rated working condition. At this time, the current of excitation coil 410 is controlled by intelligent control algorithm.

[0148] When the displacement of piston 400 exceeds the threshold, the extreme position of piston 400 begins to exceed the damping zone 650 and enter the buffer zone 660. The magnetorheological damper with buffer function is under extreme working conditions. At this time, the current of excitation coil 410 is increased.

[0149] Preferably, in step S2, the displacement threshold is set to S. max / 2,

[0150] when At this time, the magnetorheological damper with buffer function is under rated operating conditions, which can be considered as being under common road conditions. At this time, during the movement of the magnetorheological suspension, the iron core 420 of the magnetorheological damper with buffer function of the present invention is always located in the damping zone 650. At this time, the current I of the excitation coil 410 is controlled by the intelligent control algorithm. Taking the semi-active control algorithm of the ceiling as the intelligent control algorithm as an example, the expression of the intelligent control algorithm for controlling the current I of the damping zone 650 is as follows:

[0151]

[0152] in, The damping force required for suspension vibration reduction is calculated through an intelligent control algorithm (which is then substituted into the inverse model to calculate the current required for the magnetorheological system to output that magnitude of force). This is the maximum output of the magnetorheological power; The damping coefficient; x s This represents the displacement of the upper suspension layer. x x This represents the displacement of the lower suspension layer. x This indicates the relative displacement of piston 400; x ' is the first derivative of displacement with respect to time, which represents the velocity of piston 400; I represents the current of excitation coil 410.

[0153] when At this time, the magnetorheological damper with buffer function is under extreme working conditions, which can be considered as when the road conditions are bad. At this time, the vibration amplitude of the suspension will be further increased. The displacement sensor 700 detects the movement height of the suspension. When it is detected that the suspension is about to touch the bottom or top when it is close to the limit of the travel, the iron core 420 starts to exceed the damping zone 650 and enters the buffer zone 660.

[0154] At this point, increase the current I in the excitation coil 410 so that I = I max This allows for buffer control, thus preventing the suspension from bottoming out or hitting the top.

[0155] In summary, the magnetorheological damper with buffering function and its buffering control method of this invention solve the technical problem of limited adjustable range and the inability to simultaneously achieve maximum and minimum damping forces in existing magnetorheological dampers. This invention achieves different maximum and minimum damping forces at different positions of the stroke by changing the cylinder inner diameter. Compared to ordinary magnetorheological dampers, the magnetorheological damper with buffering function of this invention better meets the actual needs of magnetorheological suspension vibration reduction, effectively resolving the conflict between comfort and bottoming / top contact in magnetorheological suspension. Furthermore, the implementation of the magnetorheological damper with buffering function of this invention is simple and does not increase costs compared to ordinary magnetorheological dampers.

[0156] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for controlling a buffer function of a magneto-rheological damper having a buffer function, characterized by, The region with a larger inner diameter in the middle of the cylinder of the controlled MR damper with buffering function is a damping region, and the regions with smaller inner diameters on both sides of the cylinder are buffering regions; the buffering control method of the MR damper with buffering function comprises the following steps: S0, according to the mechanical property test results of the MR damper with buffering function prototype, the values of each parameter in the model under different currents of the excitation coil are identified respectively, and then the relationship between each parameter and the current is fitted, so as to obtain the mechanical model of the MR damper with buffering function; In the step S0, the expression of the mechanical model of the MR damper with buffering function is: The inverse model of the mechanical model is expressed as: where F represents a damping force; x represents the relative displacement amount of the piston; x is the first derivative of the displacement with respect to time, i.e., represents the speed of movement of the piston; I represents the current of the exciting coil; S1, the displacement sensor collects the relative displacement between the upper and lower layers of the suspension, and obtains the piston displacement of the MR damper with buffering function; In said step S1, the relative displacement between the upper and lower layers of the suspension ; wherein x s is the displacement of the upper layer of the suspension, x x is the displacement of the lower layer of the suspension; The piston displacement S is converted through the functional relationship between the piston displacement and the relative displacement Δx between the upper and lower layers of the suspension, and the functional relationship is expressed as: Wherein, when the suspension is in the equilibrium position, the iron core is just located at the center of the damping region, and at this time the displacement of the iron core is S=0; S2, a displacement threshold is set, when the piston displacement is less than or equal to the threshold, the piston is always located in the damping region, and the MR damper with buffering function is in the rated working condition, at this time the current of the excitation coil is controlled through the intelligent control algorithm; When the piston displacement is greater than the threshold, the piston movement limit position begins to exceed the damping region and enters the buffering region, and the MR damper with buffering function is in the limit working condition, at this time the current of the excitation coil is increased; In the step S2, the displacement threshold value is set to S max / 2, When the magnetorheological damper with buffering function is in the rated working condition, the current I of the excitation coil is controlled by an intelligent control algorithm, and the expression of the intelligent control algorithm is as follows: wherein, is the damping force required for suspension damping calculated by the intelligent control algorithm; is the maximum output of the magneto-rheological fluid; is the damping coefficient; x s is the displacement of the upper layer of the suspension, x x is the displacement of the lower layer of the suspension; x represents the relative displacement amount of the piston; x is the first derivative of the displacement with respect to time, i.e., represents the speed of movement of the piston; I represents the current of the exciting coil; When the magnetorheological damper with buffering function is in the limit working condition, the current I of the exciting coil is increased to make I = I max .

2. A magneto-rheological damper having a buffering function, characterized by, The MR damper is controlled by the buffering control method of the MR damper with buffering function as claimed in claim 1, and the MR damper with buffering function comprises a piston rod, a cylinder, a sealing seat, a piston, and a floating piston; One end of the cylinder is open, and the sealing seat is fixedly connected to the open end of the cylinder; The piston is slidably arranged in the cylinder, one end of the piston rod is connected to the piston, the other end of the piston rod extends to the outside of the cylinder through the sealing seat, and the excitation coil is wound around the outer periphery of the piston; The floating piston is slidably arranged in the cylinder between the piston and the bottom surface of the cylinder; The inner diameter of the middle part of the cylinder is greater than the inner diameters of both sides of the cylinder.

3. The magneto-rheological damper with buffering function according to claim 2, wherein, A working flow channel is formed between the piston and the side wall of the cylinder; The region with a larger inner diameter in the middle of the cylinder is a damping region, the width of the working flow channel formed by the piston and the side wall of the cylinder in the damping region is larger, and the piston slides in the damping region with smaller damping force; The regions with smaller inner diameters on both sides of the cylinder are buffering regions, the width of the working flow channel formed by the piston and the side wall of the cylinder in the buffering region is smaller, and the piston slides in the buffering region with larger damping force.

4. The magneto-rheological damper with buffering function according to claim 3, wherein, An inclination is arranged between the region with a larger inner diameter in the middle of the cylinder and the regions with smaller inner diameters on both sides of the cylinder to form a transition region.

5. The magneto-rheological damper with buffering function according to claim 4, wherein, A magnetic fluid is filled between the lower end surface of the sealing seat and the upper end surface of the floating piston in the cylinder; a gas chamber is formed by filling a gas between the lower end surface of the floating piston and the bottom surface of the cylinder, and the bottom surface of the cylinder is provided with a gas flow channel.

6. The magneto-rheological damper with buffering function according to claim 5, wherein, A recovery cavity is formed between the piston and the sealing seat, and a compression cavity is formed between the piston and the floating piston, and the recovery cavity and the compression cavity are communicated through the working flow channel; When the piston slides in the direction close to the sealing seat, the magnetic fluid in the recovery cavity is extruded and enters the compression cavity through the working flow channel; When the piston slides in the direction close to the bottom surface of the cylinder, the magnetic fluid in the compression cavity is extruded and enters the recovery cavity through the working flow channel; The volume change caused by the piston rod connected with the piston in and out of the inside of the cylinder is compensated by the gas chamber.

7. The magneto-rheological damper with buffering function according to claim 6, wherein, The piston comprises an iron core, which constitutes the main body of the piston, and the iron core is provided with a winding slot and a lead slot for winding and lead of the excitation coil.

8. The magneto-rheological damper with buffering function according to claim 7, wherein, The magnetic fluid damper satisfies the following design formula: wherein, F represents a damping force; L is a piston length; is an average circumference of the working runner; A p is an effective area of the core; η is a dynamic viscosity of the fluid; u is a velocity of the core relative to the cylinder; τ is a shear yield strength of the magnetorheological fluid; h is a width of the working runner.

9. The magneto-rheological damper with buffering function according to claim 8, wherein, The magnetic fluid damper with buffering function is applied to a suspension structure. The width of the damping zone working flow channel is h 1 The width of the buffer zone working flow channel is h 2 , h 1 >h 2 ; Let S be the maximum piston displacement under rated operating conditions max The length L1 of the damping zone satisfies the following equation: L is the length of the piston. The length L2 of the buffer zone satisfies the following formula: wherein, M is the upper end mechanism and the total mass of the load of the suspension; v is the relative velocity of the upper and lower ends of the suspension; F max is the maximum output damping force of the shock absorber.

10. The magnetorheological damper with a buffering function according to claim 9, wherein, Damping zone working flow channel width h 1 = 1.2 mm, buffer zone working flow channel width h 2 = 0.8 mm, damping zone length L1 = 55 mm, buffer zone length L2 = 5 mm, transition zone inclination 30°.

11. The magneto-rheological damper with buffering function according to any one of claims 1-10, wherein, The excitation coil is electrically connected or communicatively connected with the displacement sensor, and the current of the excitation coil is controlled according to the real-time detection data of the displacement sensor.

Images