Quasi-zero stiffness vibration isolation device for vehicle

Abstract

The invention discloses a vehicle quasi-zero stiffness vibration isolation device which comprises a front rack and a rear rack, a base arranged at the ends of the racks on the two sides, a fixing frame arranged on one side of the base, a positive stiffness mechanism arranged at the central axis position of the base, and negative stiffness mechanisms symmetrically arranged on the left side and the right side of the base. The negative stiffness mechanism is longitudinally arranged and is parallel to the positive stiffness mechanism, the positive stiffness mechanism is mounted on the base, and one end of the negative stiffness mechanism is connected with the base. The quasi-zero stiffness vibration isolator has the beneficial effects that the arrangement mode of an existing quasi-zero stiffness vibration isolator is changed, so that the space occupancy rate of the device is effectively reduced, and the engineering application feasibility of the device is improved; the effective action range of the quasi-zero stiffness is obviously widened, and the dynamic vibration isolation performance of the device is effectively improved; meanwhile, according to 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 the rack, and advancing or lagging of the quasi-zero stiffness characteristic range in the fixed working stroke is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of engineering vibration isolation, in particular to a quasi-zero stiffness vibration isolation device for vehicles. Background Art

[0002] Quasi-zero stiffness vibration isolators can meet the requirements of many vibration control equipment for vibration isolation technology; quasi-zero stiffness vibration isolators have the characteristics of high static stiffness and low dynamic stiffness; when it is affected by static force, the quasi-zero stiffness vibration isolation device exhibits a higher static stiffness, which makes the quasi-zero stiffness vibration isolation device have a larger load-bearing capacity; at the same time, during low-frequency vibration, the low dynamic stiffness effect of the device can effectively reduce the vibration hazard and improve the vibration isolation ability of the system at low frequencies;

[0003] In a quasi-zero stiffness system, a positive stiffness spring is placed vertically to provide static bearing capacity. 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 this by placing the negative stiffness device horizontally in parallel with the positive stiffness spring, which also causes the device to be too large. In automotive suspension applications, the available space is limited, and the application of traditional quasi-zero stiffness isolators is restricted, making it difficult to fully play their role.

[0004] In view of the above situation, it is necessary to improve the existing quasi-zero stiffness vibration isolators so that they can meet the current needs of using quasi-zero stiffness vibration isolators in automobile suspensions. Summary of the invention

[0005] The technical solution of the present invention for achieving the above-mentioned purpose is a quasi-zero stiffness vibration isolation device for a vehicle, comprising a frame arranged in front and rear, a base arranged at the ends of the frames on both sides, a fixing frame arranged on one side of the base, a positive stiffness mechanism arranged at the center axis position on the base, and a negative stiffness mechanism symmetrically arranged on the left and right sides of the base, wherein 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] To further supplement the technical solution, gears are provided on 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 through a gear shaft, the gear shaft is fixedly mounted on the frame, and a rack is provided between the gears on the left and right ends of the positive stiffness mechanism, the racks are meshed and connected to the gears on the left and right sides, and the racks are connected to the positive stiffness mechanism.

[0007] To further supplement the present technical solution, the positive stiffness mechanism includes a guide rod arranged on the central axis of the base, a first rack spring arranged on the base and on the outside of the guide rod, and a second rack spring arranged 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, 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] To further supplement the present technical solution, the negative stiffness mechanism includes a lower connecting rod arranged on a base, an upper connecting rod connected to the lower connecting rod, and a connecting rod spring arranged between the upper connecting rod and the lower connecting rod, wherein the lower connecting rod is connected to the base and can be rotatably mounted thereon, the upper connecting rod is connected to the gear and can be 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 the technical solution, sleeves are provided at the front and rear ends of the gear, and the sleeves are fixedly mounted on the frame.

[0010] As a further supplement to the technical solution, the frame is symmetrically provided with 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 the technical solution, the limiting mechanism includes a guide wheel bracket fixedly mounted on the frame, and guide wheels arranged on both sides of the guide wheel bracket, wherein the guide wheels are connected to the guide wheel bracket, and the guide wheels on both sides are respectively pressed against the rack.

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

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

[0014] The beneficial effect lies in that the present invention utilizes gears, racks and connecting rod structures to convert spring elastic force into elastic torque, thereby changing the layout of existing quasi-zero stiffness vibration isolators, thereby effectively reducing the space occupancy rate of the device and improving the feasibility of device engineering applications; the negative stiffness spring linear displacement is converted into gear rotation through gear and rack transmission, thereby amplifying the effective stroke of the negative stiffness spring elastic force, significantly broadening the effective action 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 meshing position of the gear and the rack can be adjusted, and the angle between the connecting rod spring and the rack spring can be changed to achieve the advance or lag of the quasi-zero stiffness characteristic range within a fixed working stroke. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

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

[0022] In the figure, 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 DESCRIPTION

[0023] In order to make the technical solution more clear to those skilled in the art, Figure 1-7 The technical solution of the present invention is described in detail:

[0024] A quasi-zero stiffness vibration isolation device for a vehicle comprises a frame 5 arranged at the front and rear, a base 7 arranged at the ends of the frame 5 on both sides, a fixing frame 6 arranged at one side of the base 7, a positive stiffness mechanism arranged at the center axis position on the base 7, and negative stiffness mechanisms symmetrically arranged on the left and right sides of the base 7, wherein the negative stiffness mechanism is arranged longitudinally and parallel to the positive stiffness mechanism, the positive stiffness mechanism is installed on the base 7, and one end of the negative stiffness mechanism is connected to the base 7; the present invention changes the arrangement mode of the existing quasi-zero stiffness vibration isolation device, thereby effectively reducing the space occupancy rate of the device and improving the feasibility of the device engineering application; Among them, gears 3 are also provided on the left and right ends of the frame 5, the gears 3 are connected to the negative stiffness mechanism, the gears 3 are rotatably installed on the frame 5 through the gear 3 axis, the gear 3 axis is fixedly installed on the frame 5, and a rack 1 is also provided between the gears 3 located at the left and right ends of the positive stiffness mechanism, the rack 1 is meshed and connected with the gears 3 on the left and right sides, and the rack 1 is connected to the positive stiffness mechanism; the gear 3 plays a role in transmitting torque, and the work of the positive stiffness mechanism and the negative stiffness mechanism are controlled by the cooperation between the gear 3 and the rack 1, thereby realizing the application of the quasi-zero stiffness theory in the automobile suspension and improving the vibration isolation performance of the automobile suspension.

[0025] The structure and working principle of the positive stiffness mechanism and negative stiffness mechanism will be described in detail below:

[0026] First, the positive stiffness mechanism includes a guide rod 13 arranged on the central axis of the base 7, a first rack spring 12 arranged on the base 7 and arranged on the outside of the guide rod 13, and a second rack spring 14 arranged 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, 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 and the rack 1 can move relatively thereon, 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 arranged on the base 7, an upper connecting rod 8 connected to the lower connecting rod 10, and a connecting rod spring 11 arranged 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, 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 colinear 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; when working: under the action of load, the rack 1 moves downward, and at the same time drives the gear 3 to rotate counterclockwise, squeezing 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 hinder the movement of the rack 1, and the quasi-zero stiffness vibration isolation device presents a positive stiffness characteristic; when the connecting rod is vertical, the connecting rod spring 11 is compressed to the limit, at this time the rack 1 continues to move downward, the connecting rod spring 11 begins to stretch, and the force generated by it is offset by the force generated by the first rack spring 12 and the second rack spring 14, at this time the device presents 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 not enough to offset 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 the positive stiffness characteristic.

[0027] Among them, sleeves 9 are also provided at the front and rear ends of the gear 3, and the sleeves 9 are fixedly mounted on the frame 5 to limit the lateral movement of the gear 3;

[0028] Among them, the frame 5 is also symmetrically provided with a limiting mechanism at the front and rear ends of the rack 1, and the limiting mechanism is installed on the frame 5 to limit the lateral movement of the rack 1. Furthermore, the limiting mechanism includes a guide wheel bracket 4 fixedly installed on the frame 5, and guide wheels 2 arranged on both sides of the guide wheel bracket 4, and the guide wheels 2 are connected to the guide wheel bracket 4, and the guide wheels 2 on both sides are respectively against the rack 1; wherein 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 limit the movement direction of the rack 1.

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

[0030] According to the connection characteristics of the gear 3 and the upper connecting rod 8, and the relative positions of the rotation center of the gear 3 and the rotation center of the 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 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, that is, R1; l ab is the distance between the connection center of the lower connecting rod 10 and the base 7 and the rotation center of the gear 3; l bc 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; a1 is l ac and l ab The angle between them; △a is the rotation angle of the gear; a2 is l bc and l ab The angle between them; a3 is l bc Extension cord and l ac The angle between the perpendicular lines.

[0039] In the specific implementation process, the upper connecting rod 8 is connected to the gear 3, and the gear 3 is meshed 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 Principle, we can get the following relationship:

[0041] F2=(K2+K3)·R2·a1 (8)

[0042] Among them, 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 action of the force exerted by the rack 1 on the gear 3 to the center of rotation of the gear.

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

[0044] according to Figure 6 Principle, we can get the following relationship:

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

[0046] Among them, F1 is the connecting rod spring 11 perpendicular to l ac The projection of the force in the direction of O 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, driving the gear 3 to rotate counterclockwise, and the characteristics of the connecting rod spring 11 when rotating counterclockwise are the same as those when rotating clockwise; the gear rotational inertia 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 combined equations (1), (2), (3), (4), (5), (6), (7), (8), and (9) are:

[0049] in accordance with Figure 6 , we can get the following relationship:

[0050]

[0051] Among them, F 装置 is the force presented by the quasi-zero stiffness vibration isolation device for vehicles, x is the displacement of rack 1 relative to the 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 ois the original length of the connecting rod spring, l ab is the distance between the connection center of the lower connecting rod 10 and the base 7 and the rotation center of the gear 3, l bc 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, a1 is l ac and l ab The angle formula between .

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

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

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

[0056] Depend on Figure 7 It can be seen that the specific operating conditions are as follows:

[0057] Initial position l ac Perpendicular to l ab , at this time a1 is equal to a0;

[0058] As the displacement x increases, △a gradually increases, a1 gradually decreases, and sin(a1) gradually decreases. When the displacement x = (0, 20) and the rack is in this displacement range, the device is in a positive stiffness state, and the stiffness characteristics exhibited 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, and sin(a1) changes from 0 to negative as x increases. At this time, the torque generated by the connecting rod spring offsets the positive force generated by the rack spring, making the device in a quasi-zero stiffness state, with a stiffness of 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 rack spring stiffness gradually decreases, and the device again exhibits positive stiffness characteristics.

[0061] It can be seen that the displacement x is in the range of (20,30), which is the optimal vibration isolation range of this device. F can be achieved by adjusting the device structure data. 装置 It can be equal to 0 over a larger stroke, realizing the quasi-zero characteristic of the device.

[0062] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A quasi-zero stiffness vibration isolation device for a vehicle, characterized in that: The invention comprises a frame (5) arranged at the front and rear, a base (7) arranged at the ends of the frame (5) on both sides, a fixing frame (6) arranged at one side of the base (7), a positive stiffness mechanism arranged at the central axis position of the base (7), and a negative stiffness mechanism symmetrically arranged at the left and right sides of the base (7), wherein the negative stiffness mechanism is arranged longitudinally and parallel to the positive stiffness mechanism, the positive stiffness mechanism is installed on the base (7), and one end of the negative stiffness mechanism is connected to the base (7).

2. A quasi-zero stiffness vibration isolation device for a vehicle according to claim 1, characterized in that: Gears (3) are also provided at the left and right ends of the frame (5), and the gears (3) are connected to the negative stiffness mechanism. The gears (3) are rotatably mounted on the frame (5) via a gear shaft, and the gear shaft is fixedly mounted on the frame (5). A rack (1) is also provided between the gears (3) at the left and right ends of the positive stiffness mechanism, and the rack (1) is meshedly connected with the gears (3) at the left and right sides, and the rack (1) is connected to the positive stiffness mechanism.

3. A quasi-zero stiffness vibration isolation device for a vehicle according to claim 2, characterized in that: The positive stiffness mechanism comprises a guide rod (13) arranged on the central axis of the base (7), a first rack spring (12) arranged on the base (7) and arranged outside the guide rod (13), and a second rack spring (14) arranged 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); 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) and the rack (1) can move relatively thereon; 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).

4. The quasi-zero stiffness vibration isolation device for a vehicle according to claim 2, characterized in that: The negative stiffness mechanism comprises a lower connecting rod (10) arranged on a base (7), an upper connecting rod (8) connected to the lower connecting rod (10), and a connecting rod spring (11) arranged between the upper connecting rod (8) and the lower connecting rod (10); the lower connecting rod (10) is connected to the base (7) and is rotatably mounted thereon; the upper connecting rod (8) is connected to the gear (3) and is rotatably mounted thereon; 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).

5. The quasi-zero stiffness vibration isolation device for a vehicle according to claim 2, characterized in that: The front and rear ends of the gear (3) are also provided with sleeves (9), and the sleeves (9) are fixedly mounted on the frame (5).

6. The quasi-zero stiffness vibration isolation device for a vehicle according to claim 2, characterized in that: The frame (5) is also symmetrically provided with limiting mechanisms at the front and rear ends of the rack (1), and the limiting mechanisms are mounted on the frame (5).

7. A quasi-zero stiffness vibration isolation device for a vehicle according to claim 6, characterized in that: The limiting mechanism comprises a guide wheel bracket (4) fixedly mounted on a frame (5), and guide wheels (2) arranged on both sides of the guide wheel bracket (4); the guide wheels (2) are connected to the guide wheel bracket (4), and the guide wheels (2) on both sides are respectively pressed against the rack (1).

8. The quasi-zero stiffness vibration isolation device for a vehicle according to claim 7, characterized in that: The guide wheels (2) on both sides are symmetrically arranged on both sides of the rack (1).

9. The quasi-zero stiffness vibration isolation device for a vehicle according to claim 2, characterized in that: The fixing frame (6) is provided with a fixing hole, and the rack (1) is provided with a connecting hole on a side away from the fixing frame (6).

Images