A quasi-zero stiffness vibration isolation device for a vehicle

Abstract

This invention discloses a near-zero stiffness vibration isolation device for vehicles, comprising a frame arranged at the front and rear, a base disposed at the ends of the frame on both sides, a fixing frame disposed on one side of the base, a positive stiffness mechanism disposed at the central axis position on the base, and negative stiffness mechanisms symmetrically disposed on the left and right sides of the base. The negative stiffness mechanisms are arranged longitudinally and parallel to the positive stiffness mechanisms. The positive stiffness mechanism is mounted on the base, and one end of the negative stiffness mechanism is connected to the base. The beneficial effects of this invention are that it changes the arrangement of existing near-zero stiffness vibration isolators, thereby effectively reducing the space occupancy rate of the device and improving the feasibility of its engineering application; it significantly widens the effective range of near-zero stiffness, effectively improving the dynamic vibration isolation performance of the device; and, for different working conditions, it can adjust the meshing position of the gear and rack, and change the angle between the connecting rod spring and the rack spring, to achieve the advance or lag of the near-zero stiffness characteristic range within a fixed working stroke.

Description

Technical Field

[0001] This invention relates to the field of vibration isolation technology, and in particular to a quasi-zero stiffness vibration isolation device for vehicles. Background Technology

[0002] Quasi-zero stiffness vibration isolators can meet the vibration isolation technology requirements of many vibration control equipment. Quasi-zero stiffness vibration isolators have the characteristics of high static stiffness and low dynamic stiffness. When subjected to static forces, quasi-zero stiffness vibration isolators exhibit high static stiffness, giving them a large load-bearing capacity. At the same time, during low-frequency vibrations, the low dynamic stiffness of the device can effectively reduce vibration hazards and improve the system's vibration isolation capability at low frequencies.

[0003] In a quasi-zero stiffness system, the positive stiffness spring is placed vertically to provide load-bearing capacity under static conditions. In order for the negative stiffness device to generate a force in the opposite direction to the positive stiffness spring under dynamic motion, the negative stiffness device must be connected in parallel with the positive stiffness spring. Most quasi-zero stiffness systems achieve the parallel connection of the negative stiffness device and the positive stiffness spring by placing the negative stiffness device horizontally. This results in an excessively large device size. In automotive suspension applications, where available space is limited, the application of traditional quasi-zero stiffness vibration isolators is restricted, making it difficult to fully utilize their capabilities.

[0004] In view of the above, it is necessary to improve the existing quasi-zero stiffness vibration isolators to meet the current needs of using quasi-zero stiffness vibration isolators in automotive suspensions. Summary of the Invention

[0005] The technical solution of the present invention to achieve the above objectives is a vehicle quasi-zero stiffness vibration isolation device, comprising a frame arranged at the front and rear, a base arranged at the ends of the frame on both sides, a fixing frame arranged on one side of the base, a positive stiffness mechanism arranged at the central axis position on the base, and negative stiffness mechanisms symmetrically arranged on the left and right sides of the base. The negative stiffness mechanism is arranged longitudinally and parallel to the positive stiffness mechanism. The positive stiffness mechanism is installed on the base, and one end of the negative stiffness mechanism is connected to the base.

[0006] As a further supplement to this technical solution, gears are also provided at the left and right ends of the frame. The gears are connected to the negative stiffness mechanism. The gears are rotatably mounted on the frame via a gear shaft, and the gear shaft is fixedly mounted on the frame. A rack is also provided between the gears at the left and right ends of the positive stiffness mechanism. The rack meshes with the gears on the left and right sides and is connected to the positive stiffness mechanism.

[0007] As a further supplement to this technical solution, the positive stiffness mechanism includes a guide rod disposed on the central axis of the base, a first rack spring disposed on the base and outside the guide rod, and a second rack spring disposed between the rack and the guide rod. One end of the guide rod is fixedly installed on the base, one end of the first rack spring is fixedly connected to the base, and the other end of the first rack spring is fixedly connected to the lower end of the rack. The guide rod passes through the rack and the rack can move relative to it. One end of the second rack spring is fixedly connected to the guide rod, and the other end of the second rack spring is fixedly connected to the rack.

[0008] As a further supplement to this technical solution, the negative stiffness mechanism includes a lower connecting rod disposed on the base, an upper connecting rod connected to the lower connecting rod, and a connecting rod spring disposed between the upper connecting rod and the lower connecting rod. The lower connecting rod is connected to the base and rotatably mounted thereon, the upper connecting rod is connected to a gear and rotatably mounted thereon, one end of the connecting rod spring is fixedly connected to the lower connecting rod, and the other end of the connecting rod spring is fixedly connected to the upper connecting rod.

[0009] As a further supplement to this technical solution, sleeves are provided at both ends of the gear, and the sleeves are fixedly installed on the frame.

[0010] As a further supplement to this technical solution, the frame is also provided with symmetrical limiting mechanisms at the front and rear ends of the rack, and the limiting mechanisms are installed on the frame.

[0011] As a further supplement to this technical solution, the limiting mechanism includes a guide wheel bracket fixedly installed on the frame and guide wheels disposed on both sides of the guide wheel bracket. The guide wheels are connected to the guide wheel bracket, and the guide wheels on both sides abut against the rack.

[0012] As a further addition to this technical solution, the guide wheels on both sides are symmetrically arranged on both sides of the rack.

[0013] As a further supplement to this technical solution, the fixing frame is provided with fixing holes, and the rack is provided with connecting holes on the side away from the fixing frame.

[0014] Its beneficial effects are as follows: This invention utilizes a gear, rack, and connecting rod structure to convert the spring's elastic force into elastic torque, changing the arrangement of existing quasi-zero stiffness vibration isolators, thereby effectively reducing the space occupancy rate of the device and improving the feasibility of its engineering application; by converting the linear displacement of the negative stiffness spring into gear rotation through gear and rack transmission, the effective stroke of the negative stiffness spring's elastic force is amplified, significantly widening the effective range of quasi-zero stiffness, and effectively improving the dynamic vibration isolation performance of the device; at the same time, for different working conditions, the angle between the connecting rod spring and the rack spring can be changed by adjusting the meshing position of the gear and rack, thereby achieving the advance or lag of the quasi-zero stiffness characteristic range within a fixed working stroke. Attached Figure Description

[0015] Figure 1 This is a three-dimensional view of the structure of the present invention;

[0016] Figure 2 This is a left view of the structure of the present invention;

[0017] Figure 3 This is a top view of the structure of the present invention;

[0018] Figure 4 This is a front view of the structure of the present invention.

[0019] Figure 5 This is an exploded cross-sectional view of the structure of the present invention.

[0020] Figure 6 This is a schematic diagram of the structure of the present invention;

[0021] Figure 7 This is the resultant force-displacement curve of the present invention;

[0022] In the diagram, 1. rack; 2. guide wheel; 3. gear; 4. guide wheel bracket; 5. frame; 6. fixed frame; 7. base; 8. upper connecting rod; 9. sleeve; 10. lower connecting rod; 11. connecting rod spring; 12. first rack spring; 13. guide rod; 14. second rack spring. Detailed Implementation

[0023] To facilitate a clearer understanding of this technical solution for those skilled in the art, the following will be described in conjunction with the appendix. Figure 1-7 The technical solution of the present invention is described in detail below:

[0024] A near-zero stiffness vibration isolation device for vehicles includes a frame 5 arranged at the front and rear, a base 7 arranged at the ends of the two side frames 5, a fixing frame 6 arranged on one side of the base 7, a positive stiffness mechanism arranged at the central axis position on the base 7, and negative stiffness mechanisms symmetrically arranged on the left and right sides of the base 7. The negative stiffness mechanisms are arranged longitudinally and parallel to the positive stiffness mechanisms. The positive stiffness mechanism is installed on the base 7, and one end of the negative stiffness mechanism is connected to the base 7. This invention changes the arrangement of existing near-zero stiffness vibration isolators, thereby effectively reducing the space occupancy rate of the device and improving the feasibility of the device in engineering applications. Among them, gears 3 are provided at both ends of the frame 5. Gears 3 are connected to the negative stiffness mechanism. Gears 3 are rotatably mounted on the frame 5 through gear 3 shaft. The gear 3 shaft is fixedly mounted on the frame 5. A rack 1 is provided between the gears 3 at both ends of the positive stiffness mechanism. The rack 1 meshes with the gears 3 on both sides and is connected to the positive stiffness mechanism. Gears 3 play the role of transmitting torque. The operation of the positive stiffness mechanism and the negative stiffness mechanism are controlled by the cooperation of gears 3 and rack 1, thereby realizing the application of quasi-zero stiffness theory in automobile suspension and improving the vibration isolation performance of automobile suspension.

[0025] The structure and working principle of positive stiffness mechanisms and negative stiffness mechanisms will be explained in detail below:

[0026] First, the positive stiffness mechanism includes a guide rod 13 positioned along the central axis of the base 7, a first rack spring 12 positioned on the base 7 and outside the guide rod 13, and a second rack spring 14 positioned between the rack 1 and the guide rod 13. One end of the guide rod 13 is fixedly mounted on the base 7, one end of the first rack spring 12 is fixedly connected to the base 7, and the other end of the first rack spring 12 is fixedly connected to the lower end of the rack 1. The guide rod 13 passes through the rack 1, allowing the rack 1 to move relative to it. One end of the second rack spring 14 is fixedly connected to the guide rod 13, and the other end of the second rack spring 14 is fixedly connected to the rack 1. The negative stiffness mechanism includes a lower connecting rod 10 positioned on the base 7, an upper connecting rod 8 connected to the lower connecting rod 10, and a connecting rod spring 11 positioned between the upper connecting rod 8 and the lower connecting rod 10. The lower connecting rod 10 is connected to the base 7 and rotatably mounted thereon, and the upper connecting rod 8 is connected to the gear 3 and rotatably mounted thereon. The upper connecting rod 8 and the lower connecting rod 10... In a collinear state, the upper connecting rod 8 translates along the central axis of the lower connecting rod 10. One end of the connecting rod spring 11 is fixedly connected to the lower connecting rod 10, and the other end of the connecting rod spring 11 is fixedly connected to the upper connecting rod 8. During operation: under load, the rack 1 moves downward, simultaneously driving the gear 3 to rotate counterclockwise, compressing the first rack spring 12 and the connecting rod spring 11. The first rack spring 12, the second rack spring 14, and the connecting rod spring 11 simultaneously resist the movement of the rack 1, and the quasi-zero stiffness vibration isolation device exhibits positive stiffness characteristics. When the connecting rod is vertical, the connecting rod spring 11 is compressed to its limit. At this time, the rack 1 continues to move downward, and the connecting rod spring 11 begins to stretch. The force it generates cancels out the force generated by the first rack spring 12 and the second rack spring 14. At this time, the device exhibits a quasi-zero stiffness vibration isolation state. When the rack 1 continues to move downward, the force generated by the connecting rod spring 11 is insufficient to cancel out the force generated by the first rack spring 12 and the second rack spring 14. At this time, the quasi-zero stiffness vibration isolation device returns to positive stiffness characteristics.

[0027] Among them, the front and rear ends of the gear 3 are provided with sleeves 9, which are fixedly installed on the frame 5 and restrict the lateral movement of the gear 3.

[0028] The frame 5 is symmetrically equipped with limiting mechanisms at both ends of the rack 1. The limiting mechanisms are installed on the frame 5 to restrict the lateral movement of the rack 1. Furthermore, the limiting mechanisms include guide wheel brackets 4 fixedly installed on the frame 5 and guide wheels 2 arranged on both sides of the guide wheel brackets 4. The guide wheels 2 are connected to the guide wheel brackets 4, and the guide wheels 2 on both sides abut against the rack 1. The guide wheels 2 on both sides are symmetrically arranged on both sides of the rack 1. When the rack 1 is subjected to loads in different directions, the guide wheels restrict the movement direction of the rack 1.

[0029] The fixing frame 6 is provided with fixing holes, and the rack 1 is provided with connecting holes on the side away from the fixing frame 6 for connecting loads.

[0030] Based on the connection characteristics of gear 3 and upper connecting rod 8, and the relative positions of the rotation centers of gear 3 and lower connecting rod 3, the following relationship can be obtained:

[0031]

[0032] l0 = l ab ·sina0 (2)

[0033]

[0034] a1=a0-Δa (4)

[0035]

[0036] a3 = 90° - a1 - a2 (6)

[0037]

[0038] Among them, l ac R1 is the distance between the connection center of the upper connecting rod 8 and the gear 3 and the rotation center of the gear 3. ab The distance between the connection center of the lower connecting rod 10 and the base 7 and the rotation center of the gear 3; bc a1 is the distance between the connection center of the lower connecting rod 10 and the base 7 and the connection center of the upper connecting rod 8 and the gear 3; ac and l ab The included angle between them; △a is the rotation angle of the gear; a2 is the angle between them. bc and l ab The included angle between them; a3 is l bc The extension of l ac The angle between the perpendiculars.

[0039] In the specific implementation process, the upper connecting rod 8 is connected to the gear 3, and the gear 3 meshes with the rack 1. When the rack 1 moves downward, the rack spring 12 is compressed and the rack spring 14 is stretched, generating an upward force F2.

[0040] according to Figure 6 Based on this principle, the following relationship can be obtained:

[0041] F2=(K2+K3)·R2·a1 (8)

[0042] Wherein, F2 is the force exerted by the first rack spring 12 and the second rack spring 14 on the gear, which is opposite to the torque generated by the connecting rod spring 11 on the gear 3; K2 is the stiffness of the first rack spring 12; K3 is the stiffness of the second rack spring 14; and R2 is the distance from the point of application of the force exerted by the rack 1 on the gear 3 to the center of rotation of the gear.

[0043] F2 drives gear 5 to rotate clockwise, while the first connecting rod spring 11 is in a compressed state at the initial position. As the gear rotates, the force F1 of the connecting rod spring 11 decreases.

[0044] according to Figure 6 Based on this principle, the following relationship can be obtained:

[0045] F1=K1·(l0-lbc)·cosa3=K1·(l O -lbc)·sin(a1+a2) (9)

[0046] Wherein, F1 is the link spring 11 perpendicular to l ac Projection of force in the direction of l O K1 is the original length of the connecting rod spring 11, and K1 is the stiffness of the connecting rod spring 11.

[0047] By adjusting various parameters, the torque generated by the connecting rod spring 11 on the rotation center of the gear 3 is increased; when the rack 1 moves upward, the first rack spring 12 is stretched and the second rack spring 14 is stretched, causing the gear 3 to rotate counterclockwise. The characteristics of the connecting rod spring 11 are the same when rotating counterclockwise as when rotating clockwise; the rotational inertia of the gear is ignored.

[0048] according to Figure 6 Taking the gear as the center of consideration, according to the ideal state, the torque on the gear is 0, and the equations (1), (2), (3), (4), (5), (6), (7), (8), and (9) are combined.

[0049] in accordance with Figure 6 The following relationship can be obtained:

[0050]

[0051] Where F 装置 Let x represent the force exhibited by the near-zero stiffness vibration isolation device for automobiles, and let x represent the displacement of rack 1 relative to its initial position.

[0052] K1 is the force generated by the connecting rod spring 11, K2 is the stiffness of the first rack spring 12, K3 is the stiffness of the second rack spring 14, and R1 is the distance from the rotation center of the upper connecting rod 8 on the gear 3 to the rotation center of the gear 3, which is equal to l. ac R2 is the radius of gear 3, l ol is the original length of the connecting rod spring. ab The distance between the connection center of the lower connecting rod 10 and the base 7 and the rotation center of the gear 3 is l. bc a1 is the distance between the connection center of the lower connecting rod 10 and the base 7 and the connection center of the upper connecting rod 8 and the gear 3. ac and l ab Formula for the included angle between them.

[0053] As attached Figure 7 The figure shows the resultant force-displacement curve of this device. The specific parameters of the device are set as follows: R1 = 20.

[0054] R2 = 33; the distance from the rotation center of the upper connecting rod 8 to the rotation center of the gear is l. ac =R1=20; stiffness of connecting rod spring 11 K1=K2=3; center distance of gear 3 from fixed point b l bc =60.

[0055] When a load is applied, the connecting rod is tangent to the outer side of gear 3, which is the initial position; the downward direction of rack 1 is the positive direction of displacement x, and as rack 1 moves downward, gear 3 rotates clockwise.

[0056] Depend on Figure 7 The specific operating status is as follows:

[0057] initial position l ac Perpendicular to l ab At this point, a1 equals a0;

[0058] As displacement x increases, Δa gradually increases, a1 gradually decreases, and sin(a1) gradually decreases. When the displacement x = (0, 20) and the rack is within this displacement range, the device is in a positive stiffness state, and the stiffness characteristics it exhibits are consistent with those of an ordinary spring.

[0059] When the displacement x reaches 20, a1 = 0. As x continues to increase, a1 becomes negative. sin(a1) changes from 0 to negative as x increases. At this time, the torque generated by the connecting rod spring cancels out the positive force generated by the rack spring, so that the device is in a quasi-zero stiffness state, and the stiffness is almost 0.

[0060] When the displacement x reaches 30, as the displacement x increases, the influence of the force generated by the connecting rod spring 11 on the stiffness of the rack spring gradually decreases, and the device once again exhibits positive stiffness characteristics.

[0061] Therefore, the optimal vibration isolation range for this device is within the displacement x range of (20, 30). This can be achieved by adjusting the device's structural data. 装置 It can achieve zero over a large stroke, thus realizing the quasi-zero characteristic of this device.

[0062] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A near-zero stiffness vibration isolation device for vehicles, characterized in that, It includes a frame arranged at the front and rear, a base arranged at the ends of the frame on both sides, a fixed frame arranged on one side of the base, a positive stiffness mechanism arranged on the central axis of the base, and negative stiffness mechanisms symmetrically arranged on the left and right sides of the base. The negative stiffness mechanism is arranged longitudinally and parallel to the positive stiffness mechanism. The positive stiffness mechanism is installed on the base, and one end of the negative stiffness mechanism is connected to the base. Gears are also provided at the left and right ends of the frame. The gears are connected to the negative stiffness mechanism. The gears are rotatably mounted on the frame via a gear shaft. The gear shaft is fixedly mounted on the frame. A rack is also provided between the gears at the left and right ends of the positive stiffness mechanism. The rack meshes with the gears on the left and right sides. The rack is connected to the positive stiffness mechanism. The positive stiffness mechanism includes a guide rod disposed on the central axis of the base, a first rack spring disposed on the base and outside the guide rod, and a second rack spring disposed between the rack and the guide rod. One end of the guide rod is fixedly mounted on the base, one end of the first rack spring is fixedly connected to the base, and the other end of the first rack spring is fixedly connected to the lower end of the rack. The guide rod passes through the rack and the rack can move relative to it. One end of the second rack spring is fixedly connected to the guide rod, and the other end of the second rack spring is fixedly connected to the rack. The negative stiffness mechanism includes a lower connecting rod disposed on a base, an upper connecting rod connected to the lower connecting rod, and a connecting rod spring disposed between the upper connecting rod and the lower connecting rod. The lower connecting rod is connected to the base and rotatably mounted thereon. The upper connecting rod is connected to a gear and rotatably mounted thereon. One end of the connecting rod spring is fixedly connected to the lower connecting rod, and the other end of the connecting rod spring is fixedly connected to the upper connecting rod.

2. The quasi-zero stiffness vibration isolation device for vehicles according to claim 1, characterized in that, The gear is also provided with sleeves at both ends, and the sleeves are fixedly installed on the frame.

3. The near-zero stiffness vibration isolation device for vehicles according to claim 1, characterized in that, The frame is also symmetrically equipped with limiting mechanisms at both ends of the rack, and the limiting mechanisms are installed on the frame.

4. The quasi-zero stiffness vibration isolation device for vehicles according to claim 3, characterized in that, The limiting mechanism includes a guide wheel bracket fixedly installed on the frame and guide wheels on both sides of the guide wheel bracket. The guide wheels are connected to the guide wheel bracket, and the guide wheels on both sides abut against the rack.

5. A near-zero stiffness vibration isolation device for vehicles according to claim 4, characterized in that, The guide wheels on both sides are symmetrically arranged on both sides of the rack.

6. The quasi-zero stiffness vibration isolation device for vehicles according to claim 1, characterized in that, The fixing frame is provided with fixing holes, and the rack is provided with connecting holes on the side away from the fixing frame.

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