Double wishbone torsion bar spring suspension

Abstract

The invention discloses a double wishbone torsion bar spring suspension, which belongs to the technical field of vehicle suspension, and comprises an upper wishbone, a steering knuckle, a lower wishbone, a torsion bar and a first mechanism; one end of the upper wishbone is connected to the steering knuckle, and the other end of the upper wishbone is connected to the frame; one end of the lower wishbone is connected to the steering knuckle, and the other end of the lower wishbone is connected to the frame; the first mechanism is connected to the front end of the torsion bar and then to the lower wishbone; the distance between the connection position of the first mechanism and the lower wishbone and the connection position of the lower wishbone and the frame is equal to a preset value; the rear end of the torsion bar is mounted on a torsion bar fixing seat; and the steering knuckle is connected to the wheel. The invention can realize any given nonlinear elastic characteristics through the mutual cooperation between the torsion bar and the first mechanism with a cam. The suspension has the advantages of simple structure, small space occupation, simple manufacturing process, etc., can be applied to a variety of vehicle models, has strong vibration isolation ability, can well protect passengers and vehicle-mounted components, and has good market application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle suspension, in particular to a double wishbone torsion bar spring suspension. Background Art

[0002] The elastic characteristics of passive suspension include linear and nonlinear. Due to structural limitations, the static deflection of linear suspension is usually not too large, resulting in a high frequency deviation (hard suspension), which leads to poor vehicle ride comfort. The ideal nonlinear elastic suspension has a low equivalent fixed frequency (soft suspension) in the regular working section, far away from the vibration frequency band that the human body is sensitive to, and can obtain a vibration isolation capability far higher than that of linear suspension. When away from the regular working section, the suspension stiffness quickly hardens, which can effectively limit the total travel of the suspension, increase the stability of the vehicle body, and easily adjust the height of the vehicle body, making the nonlinear elastic suspension increasingly valued.

[0003] The main problem in the development of nonlinear elastic suspension is to find and realize the ideal nonlinear elastic characteristics of the suspension according to the vibration isolation theory for different vehicle models and vehicle use environments. Although air spring suspension and oil-gas spring suspension have ideal nonlinear elastic characteristics and strong vibration isolation capabilities, their structures are complex and their manufacturing costs are high. They are currently only used in a few high-end models. Summary of the invention

[0004] In order to solve the problems of complex structure, high manufacturing cost and few applicable vehicle models of existing nonlinear elastic characteristic suspension, the present invention provides a double wishbone torsion bar spring suspension, including an upper wishbone, a steering knuckle, a lower wishbone, a torsion bar and a first mechanism; one end of the upper wishbone is connected to the steering knuckle, and the other end of the upper wishbone is connected to the frame; one end of the lower wishbone is connected to the steering knuckle, and the other end of the lower wishbone is connected to the frame; the first mechanism is connected to the front end of the torsion bar and then to the lower wishbone; the distance between the connection position of the first mechanism and the lower wishbone and the connection position of the lower wishbone and the frame is equal to a preset value; the rear end of the torsion bar is installed on a torsion bar fixing seat; the steering knuckle is connected to the wheel.

[0005] The double wishbone torsion bar spring suspension provided by the present invention can realize any given nonlinear elastic characteristics through the mutual cooperation of the torsion bar and the first mechanism with a cam. This suspension has the advantages of simple structure, small space occupation, simple manufacturing process, etc., can be applied to a variety of vehicle models, has strong vibration isolation ability, good vehicle smoothness, can well protect passengers and vehicle-mounted components, and has good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic structural diagram of the double wishbone torsion bar spring suspension of this embodiment;

[0007] Figure 2is a schematic diagram of the structure of the first mechanism of this embodiment;

[0008] Figure 3 It is a schematic diagram of the principle of realizing the speed change function of the double wishbone torsion bar spring suspension of this embodiment;

[0009] Figure 4 It is a schematic diagram of the comparison of the elastic characteristic curve of a certain vehicle model simulated by computer;

[0010] Figure 5 It is computer simulated Figure 4 Schematic diagram of the transmission ratio change curve of the vehicle model shown.

[0011] Figure numerals: 1-upper cross arm; 2-steering knuckle; 3-wheel; 4-lower cross arm; 5-torsion bar; 6-first mechanism; 61-ball joint; 62-cam; 63-roller; 64-ball joint; 7-torsion bar fixing seat. DETAILED DESCRIPTION

[0012] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0013] The elastic characteristics of the existing double wishbone torsion bar spring suspension are linear, the vibration isolation ability is not strong, and the torsion bar is relatively long, which makes it difficult to manufacture. Compared with the existing double wishbone torsion bar spring suspension, the double wishbone torsion bar spring suspension provided in the embodiment of the present invention adds a first mechanism between the lower wishbone and the torsion bar, through which a given nonlinear elastic characteristic can be achieved and the length of the torsion bar can be shortened.

[0014] See also Figure 1 and Figure 2 The double wishbone torsion bar spring suspension provided by the embodiment of the present invention comprises an upper wishbone 1, a steering knuckle 2, a lower wishbone 4, a torsion bar 5 and a first mechanism 6; one end of the upper wishbone 1 is connected to the steering knuckle 2, and the other end of the upper wishbone 1 is connected to the frame; one end of the lower wishbone 4 is connected to the steering knuckle 2, and the other end of the lower wishbone 4 is connected to the frame; the first mechanism 6 is connected to the front end of the torsion bar 5 and then connected to the lower wishbone 4; the distance between the connection position of the first mechanism 6 and the lower wishbone 4 and the connection position of the lower wishbone 4 and the frame is equal to a preset value a, and the preset value a is greater than 0 and less than the length of the lower wishbone 4; the rear end of the torsion bar 5 is installed on a torsion bar fixing seat 7, and the torsion bar fixing seat 7 is connected to the frame; the steering knuckle 2 is connected to the wheel 3.

[0015] See also Figure 1 and Figure 2In this embodiment, the first mechanism 6 includes a ball joint 61, a cam 62 and a roller 63; the cam 62 is connected to the front end of the torsion bar 5 and then connected to the lower cross arm 4 through the ball joint 61 to adapt to the slight swing of the torsion bar; the roller 63 is fixed on the frame, and the roller 63 contacts the cam 62. When working, the cam 62 can move along the roller 63. In this embodiment, the other end of the lower cross arm 4 is connected to the frame through a ball joint 64. In a specific application, the working surface line of the cam 62 is determined according to the given ideal nonlinear elastic characteristics of the suspension, the structural dimensions and the stiffness of the torsion bar.

[0016] Figure 2 The position shown is the static equilibrium position of the double wishbone torsion bar spring suspension of the embodiment of the present invention, at which the lower wishbone 4 is in the horizontal plane, the torsion bar 5 has a preload torque, and the reaction force generated by the torque is balanced with the gravity distributed to the suspension when the car is fully loaded. Under the action of the preload force, the middle part of the cam 62 is close to the roller 63, and the distance between the contact point and the lower wishbone 4 is b.

[0017] The first mechanism provided in the embodiment of the present invention has the functions of deceleration and speed change, and the specific principles are as follows:

[0018] 1. Speed ​​reduction principle: In the static equilibrium position, the basic transmission ratio i0 of the first mechanism is determined by factors such as the preset value a and the distance b between the contact point and the lower cross arm 4. Assuming that the swing angle of the lower cross arm is α and the torsion bar torsion angle is β, then β=α / i0. Compared with the torsion bar torsion angle of the existing double wishbone torsion bar spring suspension is equal to the swing angle of the lower cross arm, the torsion bar torsion angle is reduced by i0 times, so that the length of the torsion bar can be shortened, thereby reducing the difficulty of torsion bar manufacturing and material requirements, and facilitating the overall layout of the torsion bar spring suspension.

[0019] 2. Speed ​​change principle: Figure 2 As shown, the front end of the torsion bar 5 is connected to the lower cross arm 4 through the ball joint 61, the distance between the ball joint 61 and the ball joint 64 is a preset value a, and the front end of the torsion bar 5 is fixedly connected to the cam 62 in the vertical direction; when the torsion bar 5 has a preload, the cam 62 is close to the roller 63; when in the static balance position, the contact point between the roller 63 and the cam 62 and the lower cross arm 4 is at a distance b, and the working surface line of the cam 62 is determined according to the given ideal nonlinear elastic characteristics of the suspension, the structural dimensions and the torsion bar stiffness. When the lower cross arm 4 swings up and down with the uneven road surface, the roller 63 contacts different parts of the working surface of the cam 62, thereby obtaining different transmission ratios, that is, obtaining a nonlinear change in the torsion angle of the torsion bar, thereby realizing a nonlinear change in the torsion force.

[0020] See also Figure 2 and Figure 3In actual application, when the wheel encounters a bump on the road surface, the lower cross arm 4 swings counterclockwise by an angle α, and drives the torsion bar 5 and the cam 62 to move upward through the ball joint 61. The contact point between the roller 63 and the cam 62 moves from point c to point e, and the cam 62 drives the torsion bar 5 to swing by an angle β, and there is a relationship β=α / i, i is the transmission ratio of the mechanism; for ease of understanding, it is first assumed that there is no cam 62, the lower cross arm rotates by an angle α, and the torsion bar twists by an angle β, and in this embodiment, due to the existence of the cam 62, the torsion bar will twist by an additional angle Δβ, and the total twisting angle of the torsion bar is β+Δβ, that is, with the cam 62, the twisting angle of the torsion bar increases, and the transmission ratio i decreases; the roller 63 contacts the cam 62 at different positions, and Δβ is different, that is, the size of Δβ depends on the working surface shape of the cam 62, thereby realizing variable transmission ratio transmission. As mentioned above, the working surface line of cam 62 is determined according to the given ideal nonlinear elastic characteristics of the suspension, structural dimensions and torsion bar stiffness, and the torsion amount of the torsion bar spring is controlled by the working surface line of cam 62, so that the suspension of this embodiment can fully realize any given suspension elastic characteristics.

[0021] Figure 4 The elastic characteristic curve of a certain vehicle model simulated by computer, wherein curve 1 is the elastic characteristic curve of the existing double wishbone torsion spring suspension (approximately a straight line), and curve 2 is the nonlinear elastic characteristic curve of the double wishbone torsion bar spring suspension of this embodiment. Figure 4 In the figure, the ordinate is the elastic restoring force of the suspension, and the abscissa is the suspension stroke. According to the vibration isolation theory, the cam working surface curve of this vehicle model is designed. From the simulation results, it can be seen that the equivalent stiffness of the suspension is low near the static equilibrium position, and the suspension is soft. In about 75% of the suspension stroke, the modulus of the suspension transfer function is less than 1, so good vibration isolation performance can be obtained. In the section away from the normal working area, the stiffness increases rapidly, which effectively limits the total stroke of the suspension and increases the stability of the vehicle body. Figure 5 It is a part of the transmission ratio variation curve of the swing angle α of the lower cross arm and the torsion bar angle β of the vehicle model simulated by computer; Figure 5 In the figure, the ordinate is the transmission ratio of the first mechanism, and the abscissa is the swing angle of the lower cross arm. Figure 5 A section of the lower cross arm from the horizontal position to a counterclockwise swing of 15 degrees was captured. It can be seen that in the static equilibrium position, the first mechanism has a maximum transmission ratio i0. As the swing angle of the lower cross arm increases, the transmission ratio begins to decrease slowly, and then decreases rapidly. The transmission ratio is no longer a constant, thereby realizing a nonlinear change in the torsion angle of the torsion bar, which also means a nonlinear change in the torsion torque of the torsion bar and the elastic restoring force of the suspension.

[0022] The double wishbone torsion bar spring suspension provided in the embodiment of the present invention can realize any given nonlinear elastic characteristics through the mutual cooperation between the torsion bar and the first mechanism with a cam. This suspension has the advantages of simple structure, small space occupation, simple manufacturing process, etc., can be applied to a variety of vehicle models, has strong vibration isolation ability, good vehicle smoothness, can well protect passengers and vehicle-mounted components, and has good market application prospects.

[0023] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A double wishbone torsion bar spring suspension, characterized in that: The invention comprises an upper cross arm (1), a steering knuckle (2), a lower cross arm (4), a torsion bar (5) and a first mechanism (6); one end of the upper cross arm (1) is connected to the steering knuckle (2), and the other end of the upper cross arm (1) is connected to a vehicle frame; one end of the lower cross arm (4) is connected to the steering knuckle (2), and the other end of the lower cross arm (4) is connected to the vehicle frame; the first mechanism (6) is connected to the front end of the torsion bar (5) and then connected to the lower cross arm (4); the distance between the connection position of the first mechanism (6) and the lower cross arm (4) and the connection position of the lower cross arm (4) and the vehicle frame is equal to a preset value a, and the preset value a is greater than 0 and less than the length of the lower cross arm (4); the rear end of the torsion bar (5) is mounted on a torsion bar fixing seat (7); the steering knuckle (2) is connected to the wheel (3); The first mechanism (6) comprises a ball joint (61), a cam (62) and a roller (63); the cam (62) is connected to the front end of the torsion bar (5) and then connected to the lower cross arm (4) via the ball joint (61); the roller (63) is fixed to the vehicle frame, the roller (63) contacts the cam (62), and the cam (62) can move along the roller (63); the other end of the lower cross arm (4) is connected to the vehicle frame via the ball joint (64); the working surface of the cam (62) is determined according to the given ideal nonlinear elastic characteristics of the suspension, the structural dimensions and the stiffness of the torsion bar; When in the static equilibrium position, the contact point between the roller (63) and the cam (62) is above the lower cross arm (4); when the wheel encounters a bump on the road surface, the lower cross arm (4) swings counterclockwise by an angle α, driving the torsion bar (5) and the cam (62) to move upward through the ball joint (61), and the contact point between the roller (63) and the cam (62) moves downward from the static equilibrium position along the working surface of the cam (62), and the cam (62) drives the torsion bar (5) to swing by an angle β, and there is a relationship β=α / i, where i is the transmission ratio of the mechanism; through the cam (62), the torsion angle of the torsion bar (5) increases, and the transmission ratio i of the mechanism decreases.

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