Variable-stiffness magnetorheological damper with bypass holes and capable of keeping low-speed stability

Abstract

The utility model provides a variable-stiffness magnetorheological damper with bypass holes and capable of keeping low-speed stability. The magnetorheological damper is mainly composed of a piston rod, a piston head, a spring, a floating piston, a magnet exciting coil, a cylinder barrel and the like. Under the action of a magnetic field, an annular flow channel in the piston head generates a magnetorheological effect, so that the shear yield stress of magnetorheological fluid is increased, and damping force is generated. The floating piston is not only used for compensating volume change, but also provides resistance for the piston through the spring connected with the floating piston; the magnitude of the damping force can be changed by changing the magnitude of the current introduced into the magnet exciting coil; and different pressures are provided for the floating piston, so that the compression amount of the spring is changed, and the rigidity of the magnetorheological damper is changed. A bypass hole without a magnetic field effect is formed in the piston; when the speed of the piston is low, the magnetorheological fluid passes through the bypass hole under the pressure difference between the left hydraulic cavity and the right hydraulic cavity, so that the output damping force is reduced, sudden changes of the damping force and rigidity under the low-speed working condition are reduced, and the working stability is improved.

Description

Technical Field

[0001] This utility model relates to a magnetorheological damper, and more particularly to a variable stiffness magnetorheological damper with a bypass hole to maintain low-speed stability. Background Technology

[0002] Magnetorheological dampers are a new type of intelligent damping device that uses magnetorheological fluid as the working medium. Based on the magnetorheological effect, magnetorheological dampers have advantages such as simple structure, small size, low energy consumption, and fast response. Due to their adjustable damping characteristics, they are widely used in vibration control fields such as automobiles, vibration reduction, and prosthetics.

[0003] Currently, most variable stiffness and variable damping magnetorheological dampers typically consist of inner and outer cylinders combined with multiple springs to achieve variable damping and stiffness. This structure is relatively complex, and the design of the inner and outer cylinders also increases the overall volume. Furthermore, under low-speed conditions, the piston head structure of traditional magnetorheological dampers exhibits abrupt changes in damping force, leading to sudden changes in stiffness during stiffness adjustment. These limitations make it difficult to meet the practical application requirements and operational stability under different operating conditions.

[0004] Based on this, this utility model proposes a variable stiffness magnetorheological damper with a bypass hole to maintain low-speed stability. The variable damping and variable stiffness of a single cylinder are achieved by connecting the inner and outer springs and the damper in series and parallel, which has the advantage of compact structure. Furthermore, by setting a bypass hole on the basis of the traditional piston structure, the sudden change in damping force and stiffness of the damper under low-speed conditions is reduced, thereby improving the stability of operation. Summary of the Invention

[0005] In order to overcome the shortcomings of the magnetorheological dampers described in the background art and meet the requirements of engineering applications, this utility model proposes a variable stiffness magnetorheological damper with a bypass hole to maintain low-speed stability. This magnetorheological damper mainly consists of a piston rod, piston head, spring, floating piston, excitation coil, and cylinder. The winding frame inside the piston head cooperates with the piston sleeve to form an annular fluid flow channel. Under the action of a magnetic field, a magnetorheological effect occurs at the annular fluid flow channel, increasing the shear yield stress of the magnetorheological fluid and generating a damping force that hinders the movement of the piston rod. The external and internal springs work together to compress and generate stiffness. While the floating piston compensates for volume changes, the connected spring transmits the force back to the piston. By changing the magnitude of the damping force, the compression of the spring can be changed, thereby altering the stiffness of the damper. Effective control of the damping force and stiffness can be achieved by changing the magnitude of the current flowing through the excitation coil inside the piston head. A bypass fluid flow hole without a magnetic field is provided on the piston. When the piston rod speed is low, the magnetorheological fluid passes through the bypass hole under the pressure difference between the left and right hydraulic chambers, thereby reducing the output damping force and minimizing abrupt changes in damping force and stiffness.

[0006] The technical solution adopted by this utility model to solve its technical problem includes: left lifting lug (1), damper left end cover I (2), piston rod (3), damper left end cover II (4), spring I (5), cylinder (6), piston head left end cover (7), excitation coil (8), piston sleeve (9), winding frame (10), piston head right end cover (11), locking nut (12), floating piston (13), spring II (14), damper right end cover (15); the piston rod (3) is processed into a stepped shape, with a lead hole at the left end, and the outer circumferential surface of both ends is processed with an outer Threaded; the left end cover I (2) of the damper is positioned by the left shoulder (301) of the piston rod (3) and is threadedly fixed to the piston rod (3) by the left lifting lug (1); the left end cover II (4) of the damper is fixedly connected to the cylinder (6) by screws and sealed by a sealing ring; the piston rod (3) passes through the central through hole of the left end cover II (4) of the damper and is sealed by a sealing ring; the excitation coil (8) is wound on the winding frame (10); the left end cover (7) of the piston head is provided with an arc groove I (701) and a bypass hole I (702); the winding frame (10) is provided with a bypass hole I (702). Through hole Ⅲ (1001); the right end cover (11) of the piston head is provided with arc groove Ⅱ (1101) and bypass hole Ⅱ (1102); the bypass hole Ⅰ (702) on the left end cover (7) of the piston head, the bypass hole Ⅲ (1001) on the winding frame (10), and the bypass hole Ⅱ (1102) on the right end cover (11) of the piston head are aligned in sequence, installed on the piston rod (3), and fixed by locking nut (12); a floating piston (13) is provided in the cylinder (6); the right end cover (15) of the damper and the cylinder (6) are fixedly connected by screws and sealed by sealing ring. A spring I (5) is provided between the left end cover I (2) of the damper and the right end cover (15) of the damper; a spring II (14) is provided between the floating piston (13) and the right end cover (15) of the damper; the space between the left end cover II (4) of the damper, the cylinder (6) and the left end cover (7) of the piston head forms the left hydraulic chamber; the space between the cylinder (6), the right end cover (11) of the piston head and the floating piston (13) forms the right hydraulic chamber; the gap between the piston sleeve (9) and the winding frame (10) forms an annular fluid flow channel; the left hydraulic chamber, the right hydraulic chamber and the annular fluid flow channel are filled with magnetorheological fluid.

[0007] Compared with the prior art, the advantages of this utility model are:

[0008] (1) The magnetorheological damper of this utility model changes the damping force by adjusting the current, thereby changing the pressure of the right hydraulic chamber of the cylinder, and then changing the compression of the spring II connected to the floating piston, thus realizing the variable stiffness of the magnetorheological damper. Its structure is compact and occupies little space. (2) The magnetorheological damper of this utility model forms an additional flow channel under low-speed conditions by opening bypass holes on the left end cover of the piston head, the winding frame and the right end cover of the piston head, which effectively reduces the flow resistance of the magnetorheological fluid and avoids the step change of damping force and stiffness. At the same time, the single-cylinder structure combined with the series and parallel layout of the inner and outer springs reduces internal friction and response delay, further ensuring the smooth transition of damping force with speed change, and significantly improving the stability and accuracy of low-speed vibration control. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of this utility model.

[0011] Figure 2 This is a schematic diagram of the left end cap of the piston head of this utility model.

[0012] Figure 3 This is a schematic diagram of the winding frame of this utility model.

[0013] Figure 4 This is a schematic diagram of the right end cap of the piston head of this utility model.

[0014] Figure 5 This is a schematic diagram of the piston rod of this utility model.

[0015] Figure 6 This is a schematic diagram of the piston sleeve of this utility model.

[0016] Figure 7 This is a diagram showing the distribution of magnetic field lines on the piston of this utility model.

[0017] Explanation of reference numerals in the attached figures:

[0018] 1-Left lifting lug, 2-Damper left end cover I, 3-Piston rod, 4-Damper left end cover II, 5-Spring I, 6-Cylinder, 7-Piston head left end cover, 8-Excitation coil, 9-Piston sleeve, 10-Winding frame, 11-Piston head right end cover, 12-Locking nut, 13-Floating piston, 14-Spring II, 15-Damper right end cover. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0020] Figure 1 The diagram shown is a schematic of the structure of this utility model. Left lifting lug (1), left end cover of damper I (2), piston rod (3), left end cover of damper II (4), spring I (5), cylinder (6), left end cover of piston head (7), excitation coil (8), piston sleeve (9), winding frame (10), right end cover of piston head (11), locking nut (12), floating piston (13), spring II (14), right end cover of damper (15).

[0021] Figure 2 This is a schematic diagram of the left end cap of the piston head of this utility model. The left end cap (7) of the piston head has an arc-shaped groove I (701) and a bypass hole I (702).

[0022] Figure 3 This is a schematic diagram of the winding frame of this utility model. The winding frame (10) has a bypass hole Ⅲ (1001).

[0023] Figure 4 This is a schematic diagram of the right end cover of the piston head of this utility model. The right end cover (11) of the piston head has an arc-shaped groove II (1101) and a bypass hole II (1102).

[0024] Figure 5 This is a schematic diagram of the piston rod of this utility model. The piston rod (3) is machined into a stepped shape, with a left shoulder (301) and a right shoulder (302) machined on it. A lead hole is opened at the left end, and external threads are machined on the outer circumferential surface of both ends.

[0025] Figure 6 This is a schematic diagram of the piston sleeve of this utility model.

[0026] Figure 7 This is a diagram showing the distribution of magnetic field lines of the piston in this utility model. After the excitation coil (8) is energized, the magnetic field generated passes through the winding frame (10), the annular liquid flow channel formed by the winding frame (10) and the piston sleeve (9), the piston sleeve (9), the annular liquid flow channel formed by the winding frame (10) and the piston sleeve (9), and the winding frame (10) to form a closed loop.

[0027] The working principle of this utility model is as follows:

[0028] When an external excitation is input, the piston rod displaces, creating a pressure difference between the left and right hydraulic chambers inside the cylinder. Under this pressure, the magnetorheological fluid flows through the annular fluid channel and bypass hole, while the floating piston provides volume compensation. By inputting current to the excitation coil, a closed magnetic field loop is generated, sequentially passing through the winding frame, the annular fluid channel, the piston sleeve, the annular fluid channel again, and the winding frame. This causes the magnetorheological fluid flowing through the annular fluid channel to exhibit a magnetorheological effect, and its shear yield stress can be adjusted by the current, achieving variable and controllable damping of the damper. Simultaneously, during low-speed operation, the magnetorheological fluid flows through the parallel flow path formed by the annular fluid channel and the bypass hole. The bypass hole provides an additional low-resistance path, dispersing the fluid pressure gradient and preventing sudden shear stress changes caused by excessively high local flow velocities. This reduces nonlinear fluctuations in damping force and avoids abrupt changes in damping force and stiffness. Stiffness adjustment is achieved through the coordinated action of two springs. Spring I moves with the piston rod, while spring II dynamically adjusts its compression based on the pressure in the right hydraulic chamber. When a change in current causes a change in damping force, the pressure in the right hydraulic chamber changes synchronously, driving spring II to deform, thus achieving variable and controllable damper stiffness. Through the coupling of magnetic field, hydraulic system, and mechanical system, the technical effects of continuous controllability of damping force and stiffness, as well as low-speed stability, are achieved simultaneously.

Claims

1. A variable stiffness magnetorheological damper with a bypass hole for maintaining low-speed stability, characterized in that... Left lifting lug (1), damper left end cap I (2), piston rod (3), damper left end cap II (4), spring I (5), cylinder (6), piston head left end cap (7), excitation coil (8), piston sleeve (9), winding frame (10), piston head right end cap (11), locking nut (12), floating piston (13), spring II (14), damper right end cap (15); the piston rod (3) is machined into a stepped shape, with a lead hole at the left end, and external threads are machined on the outer circumference surface at both ends; the damper left end cap I (2) passes through the piston rod (3) The left shoulder (301) is positioned and is threadedly fixed to the piston rod (3) through the left lug (1); the left end cover II (4) of the damper is fixedly connected to the cylinder (6) by screws and sealed by a sealing ring; the piston rod (3) passes through the central through hole of the left end cover II (4) of the damper and is sealed by a sealing ring; the excitation coil (8) is wound on the winding frame (10); the left end cover (7) of the piston head is provided with an arc groove I (701) and a bypass hole I (702); the winding frame (10) is provided with a bypass hole III (1001); the piston The right end cap (11) of the piston head is provided with an arc groove II (1101) and a bypass hole II (1102); the bypass hole I (702) on the left end cap (7) of the piston head, the bypass hole III (1001) on the winding frame (10), and the bypass hole II (1102) on the right end cap (11) of the piston head are aligned in sequence, installed on the piston rod (3), and fixed by a lock nut (12); a floating piston (13) is provided inside the cylinder (6); the right end cap (15) of the damper is fixedly connected to the cylinder (6) by screws and sealed by a sealing ring; the left end cap of the damper A spring I (5) is provided between end cap I (2) and the right end cap (15) of the damper; a spring II (14) is provided between the floating piston (13) and the right end cap (15) of the damper; the space between the left end cap II (4) of the damper, the cylinder (6) and the left end cap (7) of the piston head forms a left hydraulic chamber; the space between the cylinder (6), the right end cap (11) of the piston head and the floating piston (13) forms a right hydraulic chamber; the gap between the piston sleeve (9) and the winding frame (10) forms an annular fluid flow channel; the left hydraulic chamber, the right hydraulic chamber and the annular fluid flow channel are filled with magnetorheological fluid.

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