Method for chassis alignment of a medium bus, alignment system and vehicle

Abstract

This invention discloses a chassis tuning method, tuning system, and vehicle for a medium-sized bus, belonging to the field of vehicle technology. The chassis tuning method includes: firstly, before assembling the torsion bar spring, pre-tightening the connecting bolts of the front and rear bushings of the lower control arm to achieve a first pre-tightening torque; then, correcting the eccentric shims of the front and rear bushings to ensure they are centered; after confirming the first pre-tightening torque is correct and the eccentric shims are centered, performing the four-wheel alignment adjustment step. That is, before the four-wheel alignment, the tightening requirements of the connecting bolts in the chassis assembly process are proposed to reduce and release the internal forces generated by the deformation of the front and rear bushings of the lower control arm, improve work efficiency and standardize the operation process, and reduce the accumulation of internal forces in the suspension system due to improper operation, thereby solving the problem of the minibus pulling to one side at the lowest cost and improving vehicle driving safety.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to a chassis tuning method, tuning system, and vehicle for a medium-sized bus. Background Technology

[0002] A vehicle's straight-line capability has a significant impact on driving safety and driving experience. If a vehicle is prone to veering off course, it not only increases the risk of traffic accidents but also increases the driver's workload and causes tire wear. For medium-sized buses (also known as minibuses), simply matching off-line vehicles through four-wheel alignment can lead to individualized problem handling, making it difficult to guarantee production consistency and repeatability. Furthermore, given the large number of passengers carried by minibuses, addressing the veering issue is particularly important for improving safety. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a chassis tuning method for medium-sized buses, which can effectively solve the problem of medium-sized buses easily veering off course and improve vehicle driving safety.

[0004] The present invention also provides a tuning system and a vehicle that perform the above-described chassis tuning method.

[0005] According to a first aspect of the present invention, a chassis tuning method for a medium-sized bus includes a chassis comprising a frame, a left suspension structure, a right suspension structure, and a torsion bar spring. The left and right suspension structures each include an upper control arm, a lower control arm, and a steering knuckle. The upper control arm is connected between the frame and the upper part of the steering knuckle. The lower control arm includes a front connecting arm and a rear connecting arm. The front connecting arm has a front bushing, and the rear connecting arm has a rear bushing. One end of the front and rear connecting arms is connected to the lower part of the steering knuckle, and the other end of the front connecting arm is connected to the frame via the front bushing. The other end of the rear connecting arm is connected to the frame via the rear bushing. The front and rear bushings are respectively connected to the frame via connecting bolts. The torsion bar spring is connected to the frame. The chassis tuning method includes:

[0006] Before assembling the torsion bar spring, the connecting bolts of the front bushing and the rear bushing are pre-tightened to a first pre-tightening torque;

[0007] The eccentric shims of the front bushing and the rear bushing are corrected so that the eccentric shims are in the center position.

[0008] Once the first preload torque is correct and the eccentric shim is centered, the four-wheel alignment adjustment of the vehicle is performed.

[0009] The chassis tuning method for a medium-sized bus according to embodiments of the present invention has at least the following beneficial effects:

[0010] The chassis tuning method is designed for medium-sized buses. First, before assembling the torsion bar springs, the connecting bolts of the front and rear bushings of the lower control arm are pre-tightened to reach the first pre-tightening torque. Then, the eccentric shims of the front and rear bushings are aligned so that they are centered, i.e., the eccentric holes of the eccentric shims are vertically upward. After confirming that the first pre-tightening torque is correct and the eccentric shims are centered, the four-wheel alignment adjustment is performed. Before the four-wheel alignment, the tightening requirements of the connecting bolts in the chassis assembly process are specified to reduce and release the internal forces generated by the deformation of the front and rear bushings of the lower control arm, improve work efficiency and standardize the operation process, and reduce the accumulation of internal forces in the suspension system due to improper operation. This addresses the problem of vehicle pull-off that plagues medium-sized buses with minimal cost, thereby improving vehicle driving safety.

[0011] According to some embodiments of the present invention, the chassis further includes a stabilizer bar, the stabilizer bar including a bar body and bent sections connected to both ends of the bar body, the frame including connected longitudinal beams and cross beams, and the chassis tuning method including:

[0012] After assembling the torsion bar spring, the torsion bar spring is adjusted to achieve the preset torque;

[0013] After adjusting the torsion bar spring, the rod is connected to the longitudinal beam, and the bent sections at both ends of the rod are respectively connected to the lower control arms of the left suspension structure and the right suspension structure.

[0014] According to some embodiments of the present invention, after the stabilizer bar is installed, the method further includes:

[0015] The steering wheel is centered using a level, and after the steering wheel is centered, it is determined whether the difference in toe angle between the left wheel and the right wheel is greater than or equal to a first preset value.

[0016] When the toe angle difference is greater than or equal to the first preset value, the steering wheel is rotated to make the toe angle difference less than the second preset value, and the steering wheel is reassembled, where the second preset value is less than the first preset value.

[0017] According to some embodiments of the present invention, performing four-wheel alignment adjustment of the vehicle includes:

[0018] The following steps are performed sequentially: adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle.

[0019] According to some embodiments of the present invention, adjusting the height of the chassis includes:

[0020] The height of the chassis is measured using an auxiliary tool. The height of the chassis is adjusted by using the upper edge of the bracket on both sides of the auxiliary tool as a reference, and the height of the chassis is adjusted by the adjusting bolt at the rear end of the torsion bar spring so that the center of the cam bolt of the lower control arm on the front side of the chassis is aligned with the reference surface of the auxiliary tool, and the height tolerance on both sides does not exceed 1mm.

[0021] After adjusting the height of the chassis, a mark is made on the corresponding cam bolt head using the reference surface of the auxiliary fixture as a reference, and the mark is used for re-inspection.

[0022] According to some embodiments of the present invention, adjusting the front wheel toe angle includes:

[0023] When the initial toe angle of the front wheel is greater than or equal to the third preset value and the caster angle value cannot be read, the toe angle of the front wheel is pre-adjusted until the caster angle value can be read.

[0024] The steps of adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle are repeated sequentially.

[0025] According to some embodiments of the present invention, a steering tie rod is provided on each side of the chassis. One side of the steering tie rod is connected to the steering knuckle of the left suspension structure, and the other side of the steering tie rod is connected to the steering knuckle of the right suspension structure. The two steering tie rods are connected by a connecting rod. The adjustment of the front wheel toe angle further includes:

[0026] After the front wheel toe angle is adjusted, the difference in the total length of the steering tie rods on both sides is set to be less than or equal to 3mm.

[0027] According to some embodiments of the present invention, adjusting the camber angle of the front wheels includes:

[0028] Adjust the connecting torque of the connecting bolt of the front bushing to the range of 48 Nm to 52 Nm. After the adjustment is completed, tighten the connecting bolt of the front bushing to the second pre-tightening torque, which is in the range of 80 Nm to 120 Nm.

[0029] According to some embodiments of the present invention, adjusting the kingpin caster angle includes:

[0030] Under the premise that the camber angle of the front wheel is qualified, adjust the caster angle of the kingpin and adjust the connecting torque of the connecting bolt of the rear bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt of the rear bushing to the third preload torque, which is in the range of 80Nm to 120Nm.

[0031] According to some embodiments of the present invention, the calibration method further includes:

[0032] When the medium-sized bus veers to one side, the height of the chassis on one side of the veergence direction is adjusted to be higher than the height on the other side, and the height difference between the two sides is less than or equal to 10mm.

[0033] The kingpin inclination angle on one side of the chassis in the direction of deviation is adjusted to be greater than that on the other side, and the difference between the kingpin inclination angles on both sides is greater than or equal to 30°.

[0034] According to a second aspect of the present invention, a chassis tuning system for a medium-sized bus includes:

[0035] The chassis includes a frame, a left suspension structure, a right suspension structure, and a torsion bar spring. The left and right suspension structures each include an upper control arm, a lower control arm, and a steering knuckle. The upper control arm connects the frame to the upper part of the steering knuckle. The lower control arm includes a front connecting arm and a rear connecting arm. The front connecting arm has a front bushing, and the rear connecting arm has a rear bushing. One end of the front and rear connecting arms is connected to the lower part of the steering knuckle, and the other end of the front connecting arm is connected to the frame via the front bushing. The other end of the rear connecting arm is connected to the frame via the rear bushing. The front and rear bushings are connected to the frame via connecting bolts. The torsion bar spring is connected to the frame. The chassis tuning system includes:

[0036] The first actuator is configured to pre-tighten the connecting bolts of the front bushing and the rear bushing to a first pre-tightening torque before assembling the torsion bar spring;

[0037] The second actuator is configured to correct the eccentric shims of the front bushing and the rear bushing so that the eccentric shims are in a centered position.

[0038] The third actuator is configured to perform four-wheel alignment adjustment of the vehicle after the first preload torque is correct and the eccentric shim is centered.

[0039] The chassis tuning system according to embodiments of the present invention has at least the following beneficial effects:

[0040] Before assembling the torsion bar spring, the first actuator performs a pre-tightening operation on the connecting bolts of the front and rear bushings of the lower control arm, achieving a first pre-tightening torque. Then, the second actuator calibrates the eccentric shims of the front and rear bushings, ensuring they are centered with their eccentric holes pointing vertically upwards. After confirming the first pre-tightening torque is correct and the eccentric shims are centered, the third actuator performs the four-wheel alignment adjustment. This involves tightening the connecting bolts in the chassis assembly process before the four-wheel alignment, reducing and releasing the internal forces generated by the deformation of the front and rear bushings of the lower control arm, improving work efficiency and standardizing the operation process. It also reduces the accumulation of internal forces in the suspension system due to improper operation, effectively addressing the vehicle's tendency to pull to one side at minimal cost, thereby improving vehicle driving safety.

[0041] According to a third aspect of the present invention, a vehicle includes a chassis, and the chassis is tuned using the chassis tuning method described in the first aspect of the present invention.

[0042] Since the vehicle uses the chassis tuning method for a medium-sized bus as described in the first aspect embodiment above, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the chassis structure of a medium-sized bus according to an embodiment of the present invention;

[0045] Figure 2 yes Figure 1 A partial schematic diagram of the left-center suspension structure and the chassis assembly structure;

[0046] Figure 3 yes Figure 1 A partial schematic diagram of the right suspension structure and the chassis assembly structure;

[0047] Figure 4 This is a flowchart of a chassis tuning method for a medium-sized bus according to an embodiment of the present invention;

[0048] Figure 5 This is a flowchart of a chassis tuning method for a medium-sized bus according to another embodiment of the present invention;

[0049] Figure 6 This is a flowchart illustrating the steps of adjusting the chassis height according to an embodiment of the present invention;

[0050] Figure 7This is a flowchart illustrating the steps of adjusting the front wheel toe angle according to an embodiment of the present invention;

[0051] Figure 8 This is a flowchart illustrating the steps of adjusting the camber and caster angles of the front wheels according to an embodiment of the present invention.

[0052] Figure 9 This is a flowchart of the steps for correcting the deviation of a medium-sized bus according to an embodiment of the present invention.

[0053] Label:

[0054] Frame 100; longitudinal beam 110; crossbeam 120; connecting seat 130;

[0055] Left suspension structure 200; left lower control arm 210; left front connecting arm 211; left front bushing 2111; left rear connecting arm 212; left rear bushing 2121; left steering knuckle 220;

[0056] Right suspension structure 300; upper right control arm 310; lower right control arm 320; front right connecting arm 321; front right bushing 3211; rear right connecting arm 322; rear right bushing 3221; right steering knuckle 330;

[0057] 400 connecting bolts;

[0058] 500 eccentric gasket;

[0059] Torsion bar spring 600; Adjusting bolt 610;

[0060] Stabilizer bar 700; bar body 710; bend section 720;

[0061] Steering tie rod 800; connecting rod 810. Detailed Implementation

[0062] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0064] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0065] In the description of this invention, it should be noted that terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0066] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0067] refer to Figures 1 to 3 This invention describes a medium-sized bus chassis according to an embodiment of the present invention. The chassis includes a frame 100, a left suspension structure 200, a right suspension structure 300, and torsion bar springs 600. The left suspension structure 200 is the left suspension for the front wheels, and the right suspension structure 300 is the right suspension for the front wheels. The frame 100 includes two longitudinal beams 110 arranged laterally and multiple crossbeams 120 connecting the two longitudinal beams 110. The length of the longitudinal beams 110 is greater than the length of the crossbeams 120. The left suspension structure 200 is mounted on the left side of the frame 100, and the right suspension structure 300 is mounted on the right side of the frame 100. Two torsion bar springs 600 are provided; one torsion bar spring 600 connects the left suspension structure 200 to the frame 100, and the other torsion bar spring 600 connects the right suspension structure 300 to the frame 100. These springs absorb and buffer impacts and vibrations caused by uneven road surfaces during vehicle operation. When the wheel encounters an obstacle, the torsion bar spring 600 undergoes torsional deformation, converting the wheel's vertical movement into the spring's torsional deformation. This effectively reduces the impact and vibration experienced by the vehicle and passengers, playing a role in buffering, shock absorption, and maintaining vehicle stability. The left suspension structure 200 and the right suspension structure 300 respectively include an upper control arm, a lower control arm, and a steering knuckle. The steering knuckle connects to the wheel, the upper control arm connects between the frame 100 and the upper part of the steering knuckle, and the lower control arm connects between the frame 100 and the lower part of the steering knuckle.

[0068] The following examples illustrate the left front suspension structure 200 and the right front suspension structure 300.

[0069] Reference Figure 2 As shown, Figure 2A partial schematic diagram of the assembly structure of the left suspension structure 200 and the frame 100 is shown. The left suspension structure 200 of the front wheel includes an upper left control arm, a lower left control arm 210, and a left steering knuckle 220. One end of the upper left control arm is connected to the upper end of the left steering knuckle 220, and the other end is hinged to the left longitudinal beam 110. The lower left control arm 210 includes a left front connecting arm 211 and a left rear connecting arm 212. The left front connecting arm 211 is provided with a left front bushing 2111, and the left rear connecting arm 212 is provided with a left rear bushing 2121. One end of the left front connecting arm 211 and the left rear connecting arm 212 are connected to the lower end of the left steering knuckle 220. Specifically, the rotatable connection can be achieved through a ball joint mechanism. The left steering knuckle 220 is used to connect the left front wheel. The left front connecting arm 211 is rotatably connected to the crossbeam 120 near the front of the frame 100 via the left front bushing 2111, and the left rear connecting arm 212 is rotatably connected to the longitudinal beam 110 of the frame 100 via the left rear bushing 2121. The crossbeam 120 and the longitudinal beam 110 are respectively provided with mounting holes. The left front bushing 2111 is connected to the mounting hole of the crossbeam 120 via the connecting bolt 400, and the left rear bushing 2121 is connected to the mounting hole of the longitudinal beam 110 via the connecting bolt 400, thereby realizing the assembly of the left suspension structure 200 of the front wheel with the frame 100.

[0070] Reference Figure 3 As shown, Figure 3 A partial schematic diagram of the assembly structure of the right suspension structure 300 and the frame 100 is shown. The right suspension structure 300 of the front wheel includes an upper right control arm 310, a lower right control arm 320, and a right steering knuckle 330. One end of the upper right control arm 310 is connected to the upper end of the right steering knuckle 330, and the other end is hinged to the right longitudinal beam 110. The lower right control arm 320 includes a right front connecting arm 321 and a right rear connecting arm 322. The right front connecting arm 321 is provided with a right front bushing 3211, and the right rear connecting arm 322 is provided with a right rear bushing 3221. One end of the right front connecting arm 321 and the right rear connecting arm 322 are connected to the lower end of the right steering knuckle 330. Specifically, the rotatable connection can be achieved through a ball joint mechanism. The right steering knuckle 330 is used to connect the right front wheel. The right front connecting arm 321 is rotatably connected to the crossbeam 120 near the front of the frame 100 via the right front bushing 3211, and the right rear connecting arm 322 is rotatably connected to the longitudinal beam 110 of the frame 100 via the right rear bushing 3221. The crossbeam 120 and the longitudinal beam 110 are respectively provided with mounting holes. The right front bushing 3211 is connected to the mounting hole of the crossbeam 120 via the connecting bolt 400, and the right rear bushing 3221 is connected to the mounting hole of the longitudinal beam 110 via the connecting bolt 400, thereby realizing the assembly of the right suspension structure 300 of the front wheel with the frame 100.

[0071] The front and rear bushings on both sides are mainly used to fill the gaps between the suspension structure and the connecting bolts 400, thus achieving a fixing effect. Because the front and rear bushings are made of rubber, they have a certain degree of elasticity, which helps to mitigate vibrations and impacts transmitted from the road surface, ensuring handling stability and making the driver feel more comfortable.

[0072] It is understood that the connecting bolt 400 between the left front bushing 2111 and the right front bushing 3211 is the first connecting bolt, and the connecting bolt 400 between the left rear bushing 2121 and the right rear bushing 3221 is the second connecting bolt. Adjusting the first connecting bolt allows for adjustment of the front wheel camber angle. Specifically, adjusting the connecting torque of the connecting bolt 400 of the left front bushing 2111 adjusts the camber angle of the left front wheel, and adjusting the connecting torque of the connecting bolt 400 of the right front bushing 3211 adjusts the camber angle of the right front wheel. Adjusting the second connecting bolt 400 allows for adjustment of the front wheel caster angle. Specifically, adjusting the connecting torque of the connecting bolt 400 of the left rear bushing 2121 adjusts the caster angle of the left rear wheel, and adjusting the connecting torque of the connecting bolt 400 of the right rear bushing 3221 adjusts the caster angle of the right front wheel.

[0073] Reference Figures 1 to 3 As shown, the chassis also includes a stabilizer bar 700, which includes a bar body 710 and bent sections 720 connected to both ends of the bar body 710. Two longitudinal beams 110 are each provided with a connecting seat 130, one of which is located near the left suspension structure 200, and the other is located near the right suspension structure 300. Both ends of the bar body 710 are rotatably connected to the two connecting seats 130, and the bent sections 720 at both ends of the bar body 710 are respectively directed towards the rear of the frame 100 and bend outwards along the width direction of the frame 100. The stabilizer bar 700 is designed to bend, with the left end of the rod 710 bent at a point 720 that connects to the left front connecting arm 211, and the connection point of the left end bent at a point 720 is located between the left front bushing 2111 and the left steering knuckle 220. The right end of the rod 710 bent at a point 720 that connects to the right front connecting arm 321, and the connection point of the right end bent at a point 720 is located between the right front bushing 3211 and the right steering knuckle 330. This design improves the overall strength of the stabilizer bar 700 and provides better stability without adding extra weight to the stabilizer bar 700.

[0074] Reference Figure 2 and Figure 3As shown, steering tie rods 800 are provided on both the left and right sides of the chassis. One end of the left steering tie rod 800 is connected to the left steering knuckle 220, and one end of the right steering tie rod 800 is connected to the right steering knuckle 330. The other ends of the left and right steering tie rods 800 are connected by a connecting rod 810. The steering tie rods 800 on both sides ensure that the two wheels can maintain synchronous movement when turning. When the driver turns the steering wheel, the steering tie rods 800 transmit motion to the left and right steering knuckles 330, thereby controlling the steering of the wheels. At the same time, the steering tie rods 800 can also adjust the wheel toe angle to ensure the straight-line driving stability of the wheels.

[0075] It is understood that the frame 100 in this embodiment can be made of aluminum alloy, using an integral hollow casting process. This process has higher material utilization and reduces welding fixtures compared to a split design, resulting in a simpler structural design and lighter weight. The crossbeam 120 and longitudinal beam 110 are respectively provided with connecting structures, and mounting holes are respectively located in these connecting structures. This allows the front and rear bushings to bear the longitudinal and lateral forces of the vehicle, resulting in more even stress distribution on the suspension, better suspension strength and durability, and improved overall vehicle stability. Furthermore, in this embodiment, the left steering knuckle 220 and right steering knuckle 330 are integrally formed structures, and both are made of aluminum alloy using a casting and forging process. This process allows the material to exhibit better mechanical properties, ensuring the connection strength between the steering knuckle and structures such as the upper control arm, lower control arm, and steering tie rod 800.

[0076] refer to Figures 4 to 9 The chassis tuning method according to an embodiment of the present invention is described below, and is applied to a medium-sized bus. The chassis tuning method is explained below with specific examples.

[0077] Reference Figure 4 As shown, the chassis tuning method for a medium-sized bus in this embodiment includes, but is not limited to, the following steps:

[0078] Step S100: Before assembling the torsion bar spring 600, the connecting bolts 400 of the front bushing and the rear bushing are pre-tightened to reach the first pre-tightening torque.

[0079] Step S200: The eccentric shims 500 of the front bushing and the rear bushing are corrected so that the eccentric shims 500 are in the center position.

[0080] Step S300: After the first preload torque is correct and the eccentric shim 500 is centered, perform four-wheel alignment adjustment of the vehicle.

[0081] Understandably, the left front bushing 2111 is connected to the mounting hole on the left side of the crossbeam 120 via connecting bolt 400, the left rear bushing 2121 is connected to the mounting hole on the left side of the longitudinal beam 110 via connecting bolt 400, the right front bushing 3211 is connected to the mounting hole on the left side of the crossbeam 120 via connecting bolt 400, and the right rear bushing 3221 is connected to the mounting hole on the right side of the longitudinal beam 110 via connecting bolt 400. The first and second connecting bolts are pre-tightened before the torsion bar spring 600 is assembled to reduce and release the influence of the internal force generated by the deformation of the front and rear bushings of the lower control arm on the torsion bar spring 600. Pre-tightening can be understood as loosening the first and second connecting bolts by a certain angle, and then applying a certain torque using a torque tool or other means to deform the first and second connecting bolts to a certain degree, achieving a certain standard of tightening force, thereby achieving the expected tightening effect. Pre-tightening effectively prevents the connecting bolts 400 from deforming and loosening due to external forces during prolonged operation, maintaining the tightness of the connection and enhancing chassis reliability. However, if the first and second connecting bolts 400 are pre-tightened after assembling the torsion bar spring 600, the internal forces generated by the deformation of the front and rear bushings will affect the torque adjustment of the torsion bar spring 600, reducing calibration accuracy.

[0082] In some embodiments, the first and second connecting bolts are pre-tightened to a first pre-tightening torque of 100 Nm, which can fluctuate by ±20 Nm, meaning the range of the first pre-tightening torque is 80 Nm to 120 Nm. This ensures the tightening force meets the tightness requirements of the minibus chassis. When the first pre-tightening torque meets the above range, it indicates that the first pre-tightening torque has reached the correct or qualified state. It can be understood that the maximum value of the first pre-tightening torque is 120 Nm, and the minimum value is 80 Nm, which can be adjusted according to actual application requirements.

[0083] Understandably, both the front and rear bushings have eccentric shims 500. Adjusting these shims allows for the adjustment of wheel alignment parameters, such as toe and camber, thus affecting vehicle handling and stability. After pre-tightening the connecting bolts 400 of the front and rear bushings, the eccentric shims 500 are aligned to ensure they are centered, with the eccentric holes of the shims 500 pointing vertically upwards, facilitating subsequent four-wheel alignment.

[0084] After steps S100 and S200, step S300 is executed. This means that once the first preload torque is correct and the eccentric shim 500 is centered, four-wheel alignment adjustment is performed. Prior to four-wheel alignment, the tightening requirements of the connecting bolts 400 in the chassis assembly process are specified to reduce and release the internal forces generated by the deformation of the front and rear bushings of the lower control arm, improving work efficiency and standardizing the operation process. Simultaneously, it reduces the accumulation of internal forces in the suspension system due to improper operation, effectively addressing the minibus's deviation problem at minimal cost, thereby improving vehicle driving safety. The purpose of four-wheel alignment adjustment is to ensure stable straight-line driving and easy steering, reducing tire and steering component wear during driving. Specifically, this can be achieved by adjusting parameters such as caster, kingpin inclination, wheel camber, and toe-in, which optimizes vehicle handling, stability, and safety.

[0085] Reference Figure 5 As shown, the chassis tuning method for a medium-sized bus in this embodiment also includes, but is not limited to, the following steps:

[0086] In step S400, after assembling the torsion bar spring 600, the torsion bar spring 600 is adjusted to achieve the preset torque.

[0087] It should be noted that after pre-tightening the connecting bolts 400 of the front and rear bushings, the two torsion bar springs 600 are assembled onto the frame 100. After assembling the torsion bar springs 600, they are adjusted to achieve the preset torque. The preset torque meets the torque requirements of the minibus chassis and can generate sufficient resistance torque when the torsion bar springs 600 undergo torsional deformation, effectively playing a role in buffering, shock absorption, and maintaining vehicle stability. The specific preset torque is set according to actual application requirements and is not specifically limited.

[0088] In step S500, after adjusting the torsion bar spring 600, the rod body 710 is connected to the longitudinal beam 110, and the bent sections 720 at both ends of the rod body 710 are connected to the lower control arms of the left suspension structure 200 and the right suspension structure 300, respectively.

[0089] It is understandable that the specific connection structure of the stabilizer bar 700 can be found in the above description. Figures 1 to 3In the embodiment shown, two longitudinal beams 110 are respectively provided with connecting seats 130. The two ends of the rod 710 are rotatably connected to the two connecting seats 130 respectively. The bent section 720 at the left end of the rod 710 is connected to the left front connecting arm 211, and the connection position of the bent section 720 at the left end is located between the left front bushing 2111 and the left steering knuckle 220. The bent section 720 at the right end of the rod 710 is connected to the right front connecting arm 321, and the connection position of the bent section 720 at the right end is located between the right front bushing 3211 and the right steering knuckle 330, thus realizing the assembly of the stabilizer bar 700. The above connection structure can improve the overall strength of the stabilizer bar 700 and play a better stabilizing role without adding extra weight to the stabilizer bar 700.

[0090] It should be noted that the pre-tightening process of the lower control arm connecting bolt 400, the assembly sequence of the stabilizer bar 700 and the torsion bar spring 600 belong to the chassis sub-assembly process. After completing the above chassis sub-assembly process, in this embodiment of the invention, before four-wheel alignment, the handbrake cable needs to be adjusted. The degree of handbrake cable adjustment is the basis for four-wheel alignment parameter adjustment. The effect of handbrake cable adjustment is that when the handbrake is lifted, the brake drum can just not rotate, and when the handbrake is released, the brake drum can rotate. This optimizes the handbrake cable adjustment, thereby reducing the yaw of the vehicle during four-wheel alignment measurement caused by parking drag and improving the accuracy of toe-in measurement.

[0091] Reference Figure 5 As shown, in this embodiment, after the installation of the stabilizer bar 700 is completed, the following steps are also included, but are not limited to:

[0092] Step S600: Use a level to center the steering wheel, and after centering the steering wheel, determine whether the difference in toe angle between the left wheel and the right wheel is greater than or equal to the first preset value.

[0093] Step S700: If the current toe angle difference is greater than or equal to the first preset value, rotate the steering wheel to make the toe angle difference less than the second preset value, and reassemble the steering wheel so that the second preset value is less than the first preset value.

[0094] Specifically, a level is used as an auxiliary measuring tool. This level can be a bubble level or a laser level, etc. It's easy to use to check if the steering wheel is horizontally aligned. After centering and adjusting the steering wheel, it's determined whether the difference in toe-in angle between the left and right wheels is greater than or equal to a first preset value. This first preset value can be set to 3°, 5°, 8°, etc., and can be selected based on the actual application requirements of the minibus.

[0095] If the current toe angle difference is greater than or equal to the first preset value, it indicates that the toe angle difference between the left and right wheels is large. Instead of adjusting the length of the steering tie rod 80°, the steering wheel is rotated to make the toe angle difference less than the second preset value, which in turn is less than the first preset value. The toe angle difference between the left and right wheels should be as close as possible; for example, the second preset value could be 0°, 1°, etc. When the second preset value is 0°, it means the toe angles of the left and right wheels are equal. When the toe angle difference is less than the second preset value, the steering wheel is reassembled and re-aligned. The process of checking whether the toe angle difference between the left and right wheels is greater than or equal to the first preset value is repeated until the steering wheel is aligned and the toe angle difference between the left and right wheels is as close as possible.

[0096] After adjusting the steering wheel, perform four-wheel alignment adjustments on the vehicle. Specifically, adjust the chassis height, front wheel camber angle, caster angle, and front wheel toe angle in sequence. This improves work efficiency and standardizes the operation process, while also helping to reduce the accumulation of internal forces in the suspension system due to improper operation.

[0097] Reference Figure 6 As shown, the steps for adjusting the chassis height in this embodiment include, but are not limited to, the following steps:

[0098] Step S800: Use the auxiliary tool to measure the height of the chassis. Using the upper edge of the bracket on both sides of the auxiliary tool as a reference, adjust the height of the chassis through the adjusting bolt 610 at the rear end of the torsion bar spring 600 so that the center of the cam bolt of the lower control arm on the front side of the chassis is aligned with the reference surface of the auxiliary tool, and the height tolerance on both sides does not exceed 1mm.

[0099] Step S900: After adjusting the height of the chassis, mark the corresponding cam bolt head with the reference surface of the auxiliary fixture as the reference, and then re-inspect the marks.

[0100] Understandably, the auxiliary tool is a measuring tool with a support structure. When using the auxiliary tool to measure the height of the chassis, it is crucial to ensure that the upper edges of the support on both sides of the auxiliary tool serve as a reference plane. This reference plane will be used to align specific parts of the chassis. The chassis height is adjusted using the adjusting bolt 610 at the rear end of the torsion bar spring 600. This step requires careful operation to ensure that the chassis height meets the predetermined requirements, satisfying the reference standard that aligns the center of the cam bolt of the lower control arm on the front side of the chassis with the reference plane of the auxiliary tool.

[0101] After alignment, check the height tolerance on both sides of the chassis. The height tolerance on both sides should not exceed 1mm. This means that the smaller the height tolerance on both sides, the closer the height values ​​on both sides of the chassis are to the design values, thus improving the dimensional accuracy of the chassis and having a positive impact on the vehicle's driving stability, handling, and safety performance. For example, the height tolerance can be 1mm, 0.8mm, 0.5mm, etc., which ensures the stability and smoothness of the chassis. If the chassis height meets the requirements and the height tolerance on both sides is within the allowable range, the measurement results should be recorded and confirmed. This embodiment of the invention proposes a requirement for left-right symmetry of the chassis height to reduce the lateral force offset of the front suspension system.

[0102] In step S900 above, after adjustment, the reference surface of the auxiliary tool is used as the reference, and a line mark is drawn on the corresponding cam bolt head to facilitate subsequent re-inspection. The position of the rear point cam bolt center of the chassis front lower control arm aligned with the reference surface of the auxiliary tool can be quickly determined. Through the above steps, the chassis height auxiliary measurement control point can be proposed, and any abnormalities in the vehicle height status can be detected in time, saving the re-inspection process, improving measurement convenience and reducing on-site equipment investment.

[0103] Reference Figure 7 As shown, the steps for adjusting the front wheel toe angle in this embodiment include, but are not limited to, the following steps:

[0104] Step S1000: When the initial toe angle of the front wheel is greater than or equal to the third preset value and the caster angle value cannot be read, the toe angle of the front wheel is pre-adjusted until the caster angle value can be read.

[0105] Step S1100: Repeat the following steps in sequence: adjust the chassis height, adjust the front wheel camber angle, adjust the caster angle, and adjust the front wheel toe angle.

[0106] It should be noted that before adjusting the front wheel toe angle, the steering wheel should be tightened so that it cannot be turned. Then, determine whether the initial front wheel toe angle is greater than or equal to the third preset value. The third preset value can be the maximum threshold for the front wheel toe angle, and the specific value should be adjusted to an appropriate value according to the actual application requirements of the vehicle model. If the initial front wheel toe angle is greater than or equal to the third preset value, it indicates that the initial front wheel toe angle is too large, causing the caster angle value to be unreadable. In this case, pre-adjust the front wheel toe angle until the caster angle value can be read. Then, repeat the process of adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle to perform four-wheel alignment adjustment.

[0107] It is understood that steering tie rods 800 are respectively installed on the left and right sides of the chassis. These tie rods ensure that the two wheels maintain synchronized movement during steering. When the driver turns the steering wheel, the tie rods 800 transmit motion to the left and right steering knuckles 330, thereby controlling the wheel steering. Since the tie rods 800 can adjust the wheel toe angle, they ensure the straight-line stability of the wheels. In this embodiment, the tie rods 800 on both sides and the connecting rod 810 constitute a steering tie rod assembly. This assembly can be understood as the total length of the tie rods 800 and the connecting rod 810 at both ends. After adjusting the front wheel toe angle, the total length of the tie rods 800 on both sides is set, with the difference in length being less than or equal to 3mm.

[0108] During the adjustment of the vehicle's front wheel toe angle, ensuring that the length difference of the steering tie rod 800 is within the aforementioned range will improve the vehicle's handling and stability. Specifically, adjust the toe angle to an appropriate value based on factors such as vehicle specifications. After adjusting the toe angle, check the length of the steering tie rod 800, setting the length difference to be less than or equal to 3mm. If the difference exceeds 3mm, adjust the length of the steering tie rod 800 until the difference meets the requirements.

[0109] Reference Figure 8 As shown in the embodiment, the steps for adjusting the front wheel camber angle and caster angle include, but are not limited to, the following steps:

[0110] Step S1200: Adjust the connecting torque of the connecting bolt 400 of the front bushing to the range of 48 Nm to 52 Nm. After the adjustment is completed, tighten the connecting bolt 400 of the front bushing according to the second pre-tightening torque, which is in the range of 80 Nm to 120 Nm.

[0111] Step S1300: Under the premise that the camber angle of the front wheel is qualified, adjust the caster angle of the kingpin and adjust the connecting torque of the connecting bolt 400 of the rear bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt 400 of the rear bushing according to the third preload torque, which is in the range of 80Nm to 120Nm.

[0112] It should be noted that the front wheel camber angle should be adjusted as little as possible. If adjustment is necessary, loosen the connecting torque of the front bushing bolt 400 to an adjustable level, approximately 50 Nm. Considering that fully loosening the front bushing bolt 400 can cause a rapid jump in camber, avoid fully loosening it. After adjustment, tighten the front bushing bolt 400 to the second preload torque, which ranges from 100 ± 20 Nm.

[0113] Because a large deviation in the front wheel camber angle may prevent the caster angle value from being read, the caster angle needs to be adjusted only after the front wheel camber angle is within acceptable limits. This means loosening the connecting torque of the rear bushing bolt 400 to an adjustable level, approximately 50 Nm. Considering that fully loosening the rear bushing bolt 400 could cause a rapid jump in the caster value, avoid fully loosening it. After adjustment, tighten the rear bushing bolt 400 to the third preload torque, which has a range of 100 ± 20 Nm.

[0114] It should be noted that all connecting bolts 400 of the lower control arm should be fully tightened according to design requirements before adjusting the toe angle. After the toe angle adjustment is completed, tighten the torque of the adjusting nuts on the steering tie rod 800, remeasure the four-wheel alignment, and save the final measurement value as the final data of the vehicle.

[0115] It is understandable that the four-wheel alignment adjustment process, including chassis height adjustment accuracy, four-wheel alignment adjustment procedures, and pre-tightening and fastening of camber and caster bolts, is a key implementation method for controlling vehicle deviation. The 700mm dimensional symmetry of the stabilizer bar is an important aspect of ensuring component quality. The steps described in the above embodiments can be adapted to the chassis height measurement control points of minibus models, improving measurement convenience and reducing on-site equipment investment. Furthermore, the requirement for left-right symmetry of chassis height is proposed to reduce lateral force deviation in the front suspension system. By proposing fastening process requirements for control arm bolts at the chassis sub-assembly station and four-wheel alignment station, the internal forces generated by front suspension bushing deformation are reduced and released. Optimization of the chassis sub-assembly process and four-wheel alignment adjustment process is proposed to improve work efficiency and standardize the operation process, while reducing the accumulation of internal forces in the suspension system due to improper operation.

[0116] Reference Figure 9 As shown, it is understandable that if the minibus is in poor driving condition and the problem of veering off course cannot be solved by normal adjustment methods, the following steps are used in some embodiments:

[0117] Step S1400: Adjust the height of the chassis on one side of the deviation direction to be higher than the other side, and the height difference between the two sides is less than or equal to 10mm.

[0118] Specifically, adjust the height of the chassis on the side that veers off course to be higher than the other side, with the maximum height difference between the two sides not exceeding 10mm. The specific height difference between the two sides depends on the degree of deviation. For example, the height difference between the two sides can be 5mm, 8mm, 10mm, etc.

[0119] Step S1500: Adjust the caster angle on the side of the chassis that is in the direction of deviation to be greater than the caster angle on the other side, and the difference between the caster angles on both sides is greater than or equal to 30°.

[0120] Specifically, adjust the caster angle on one side of the deviation to be greater than that on the other side, ensuring the difference between the two caster angles does not exceed 30°. The specific difference depends on the degree of deviation; for example, the difference could be 20°, 25°, or 30°. It can be understood that the above steps are specific measures for handling special situations and can effectively improve deviation.

[0121] It should be noted that this invention addresses the issue of vehicle misalignment in minibuses at minimal cost by controlling the chassis assembly process and the four-wheel alignment adjustment process. Furthermore, it promotes standardized operating procedures, minimizing the impact of operator differences and reducing repetitive operations, thereby improving production consistency and shortening vehicle roll-off time. This increases the first-pass yield of vehicle roll-off dynamic inspections from 40% to over 90%, significantly reducing rework and ensuring production cycle stability. Moreover, it reduces the sensitivity of vehicle straight-line capability to tires, relaxes tire cone force requirements, reduces tire defect rates, and saves development costs.

[0122] This invention also provides a chassis tuning system suitable for medium-sized buses, which can be minibuses powered by internal combustion engines or minibuses powered by electric motors (e.g., hybrid electric vehicles).

[0123] It should be noted that the chassis tuning system of the medium-sized bus includes a first actuator, a second actuator, and a third actuator. The first actuator is configured to pre-tighten the connecting bolts 400 of the front and rear bushings before assembling the torsion bar spring 600, reaching a first pre-tightening torque. Specifically, the first actuator can perform the aforementioned step S100, pre-tightening the first and second connecting bolts 400 before assembling the torsion bar spring 600. This reduces and releases the influence of the internal forces generated by the deformation of the front and rear bushings of the lower control arm on the torsion bar spring 600. Pre-tightening the connecting bolts 400 effectively prevents deformation and loosening of the connecting bolts 400 due to external forces during long-term operation, maintaining the tightness of the connection and improving chassis reliability. The second actuator is configured to correct the eccentric shims 500 of the front and rear bushings, ensuring that the eccentric shims 500 are in a centered position. The third actuator is configured to perform four-wheel alignment adjustment of the vehicle after the first preload torque is correct and the eccentric shim 500 is centered. Specifically, the second actuator can perform the above-mentioned step S200, and the third actuator can perform the above-mentioned step S300. By adjusting the eccentric shims 500 of the front and rear bushings, the wheel alignment parameters can be adjusted. After pre-tightening the connecting bolts 400 of the front and rear bushings, the eccentric shims 500 of the front and rear bushings are corrected to make the eccentric shims 500 centered, which facilitates the subsequent four-wheel alignment of the wheels.

[0124] Before assembling the torsion bar spring 600, the first actuator performs a pre-tightening operation on the connecting bolts 400 of the front and rear bushings of the lower control arm, achieving the first pre-tightening torque. Then, the second actuator calibrates the eccentric shims 500 of the front and rear bushings, ensuring that the eccentric shims 500 are in a centered position, i.e., the eccentric holes of the eccentric shims 500 are vertically upward. After confirming that the first pre-tightening torque is correct and the eccentric shims 500 are in a centered position, the third actuator performs the four-wheel alignment adjustment step of the vehicle. That is, before the four-wheel alignment, the tightening requirements of the connecting bolts 400 in the chassis sub-assembly process are proposed, reducing and releasing the internal forces generated by the deformation of the front and rear bushings of the lower control arm, improving work efficiency and standardizing the operation process. At the same time, it reduces the accumulation of internal forces in the suspension system due to improper operation, and positively solves the problem of vehicle deviation that has been troubling the minibus at the lowest cost, thereby improving vehicle driving safety.

[0125] In addition, the second actuator can also perform steps such as assembling the torsion bar spring 600 and setting the state of the stabilizer bar 700, specifically as described in steps S400 and S500 above. The third actuator can also perform four-wheel alignment steps, specifically as described in steps S800, S900, S1000, and S1100 above.

[0126] The present invention also provides a vehicle, specifically a medium-sized bus, whose chassis is tuned using the chassis tuning method described in the above embodiments. The chassis structure of the medium-sized bus is as follows: Figures 1 to 3 The structure of the embodiment shown. The chassis tuning method can be performed as follows: Figure 4 Method steps S100 to S300 Figure 5 Method steps S400 to S700 Figure 6 The method steps S800 to S900, etc.

[0127] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0128] It should be noted that the vehicle needs to have an internal combustion engine capable of outputting power, or an electric motor that acts as a generator to store mechanical energy. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle. Since the vehicle applies all the technical solutions of the above-described chassis tuning method, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.

[0129] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for chassis tuning of a medium-sized bus, characterized in that, The chassis includes a frame, a left suspension structure, a right suspension structure, and a torsion bar spring. The left and right suspension structures each include an upper control arm, a lower control arm, and a steering knuckle. The upper control arm connects the frame to the upper part of the steering knuckle. The lower control arm includes a front connecting arm and a rear connecting arm. The front connecting arm has a front bushing, and the rear connecting arm has a rear bushing. One end of the front and rear connecting arms is connected to the lower part of the steering knuckle, and the other end of the front connecting arm is connected to the frame via the front bushing. The other end of the rear connecting arm is connected to the frame via the rear bushing. The front and rear bushings are connected to the frame via connecting bolts. The torsion bar spring is connected to the frame. The chassis tuning method includes: Before assembling the torsion bar spring, the connecting bolts of the front bushing and the rear bushing are pre-tightened to a first pre-tightening torque; The eccentric shims of the front bushing and the rear bushing are corrected so that the eccentric shims are in the center position. Once the first preload torque is correct and the eccentric shim is centered, perform four-wheel alignment adjustment on the vehicle. The process of performing four-wheel alignment adjustment on the vehicle includes: The following steps are performed sequentially: adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle. Adjusting the height of the chassis includes: The height of the chassis is measured using an auxiliary tool. The height of the chassis is adjusted by using the upper edge of the bracket on both sides of the auxiliary tool as a reference, and the height of the chassis is adjusted by the adjusting bolt at the rear end of the torsion bar spring so that the center of the cam bolt of the lower control arm on the front side of the chassis is aligned with the reference surface of the auxiliary tool, and the height tolerance on both sides does not exceed 1mm. After adjusting the height of the chassis, using the reference surface of the auxiliary tool as a reference, mark the corresponding cam bolt head with a line, and then re-inspect using the mark; The adjustment of the front wheel toe angle includes: When the initial toe angle of the front wheel is greater than or equal to the third preset value and the caster angle value cannot be read, the toe angle of the front wheel is pre-adjusted until the caster angle value can be read. The steps of adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle are repeated sequentially. The chassis is provided with steering tie rods on both sides. One side of the steering tie rod is connected to the steering knuckle of the left suspension structure, and the other side of the steering tie rod is connected to the steering knuckle of the right suspension structure. The two steering tie rods are connected by a connecting rod. The adjustment of the front wheel toe angle also includes: after the front wheel toe angle is adjusted, setting the total length difference of the two steering tie rods to be less than or equal to 3mm. The adjustment of the front wheel camber angle includes: Adjust the connecting torque of the connecting bolt of the front bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt of the front bushing according to the second pre-tightening torque, which is in the range of 80Nm to 120Nm. The adjustment of the kingpin caster angle includes: Under the premise that the camber angle of the front wheel is qualified, adjust the caster angle of the kingpin and adjust the connecting torque of the connecting bolt of the rear bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt of the rear bushing to the third preload torque, which is in the range of 80Nm to 120Nm.

2. The chassis tuning method for a medium-sized bus according to claim 1, characterized in that, The chassis also includes a stabilizer bar, which includes a bar body and bent sections connected to both ends of the bar body. The frame includes connected longitudinal beams and cross beams. The chassis tuning method includes: After assembling the torsion bar spring, the torsion bar spring is adjusted to achieve the preset torque; After adjusting the torsion bar spring, the rod is connected to the longitudinal beam, and the bent sections at both ends of the rod are respectively connected to the lower control arms of the left suspension structure and the right suspension structure.

3. The chassis tuning method for a medium-sized bus according to claim 2, characterized in that, After the stabilizer bar is installed, the following is also included: The steering wheel is centered using a level, and after the steering wheel is centered, it is determined whether the difference in toe angle between the left wheel and the right wheel is greater than or equal to a first preset value. When the toe angle difference is greater than or equal to the first preset value, the steering wheel is rotated to make the toe angle difference less than the second preset value, and the steering wheel is reassembled, where the second preset value is less than the first preset value.

4. The chassis tuning method for a medium-sized bus according to claim 1, characterized in that, The calibration method also includes: When the medium-sized bus veers to one side, the height of the chassis on one side of the veergence direction is adjusted to be higher than the height on the other side, and the height difference between the two sides is less than or equal to 10mm. The kingpin inclination angle on one side of the chassis in the direction of deviation is adjusted to be greater than that on the other side, and the difference between the kingpin inclination angles on both sides is greater than or equal to 30°.

5. A chassis tuning system for a medium-sized bus, characterized in that, The chassis includes a frame, a left suspension structure, a right suspension structure, and a torsion bar spring. The left and right suspension structures each include an upper control arm, a lower control arm, and a steering knuckle. The upper control arm connects the frame to the upper part of the steering knuckle. The lower control arm includes a front connecting arm and a rear connecting arm. The front connecting arm has a front bushing, and the rear connecting arm has a rear bushing. One end of the front and rear connecting arms is connected to the lower part of the steering knuckle, and the other end of the front connecting arm is connected to the frame via the front bushing. The other end of the rear connecting arm is connected to the frame via the rear bushing. The front and rear bushings are connected to the frame via connecting bolts. The torsion bar spring is connected to the frame. The chassis tuning system includes: The first actuator is configured to pre-tighten the connecting bolts of the front bushing and the rear bushing to a first pre-tightening torque before assembling the torsion bar spring; The second actuator is configured to correct the eccentric shims of the front bushing and the rear bushing so that the eccentric shims are in a centered position. The third actuator is configured to perform four-wheel alignment adjustment of the vehicle after the first preload torque is correct and the eccentric shim is centered; The process of performing four-wheel alignment adjustment on the vehicle includes: The following steps are performed sequentially: adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle. Adjusting the height of the chassis includes: The height of the chassis is measured using an auxiliary tool. The height of the chassis is adjusted by using the upper edge of the bracket on both sides of the auxiliary tool as a reference, and the height of the chassis is adjusted by the adjusting bolt at the rear end of the torsion bar spring so that the center of the cam bolt of the lower control arm on the front side of the chassis is aligned with the reference surface of the auxiliary tool, and the height tolerance on both sides does not exceed 1mm. After adjusting the height of the chassis, using the reference surface of the auxiliary tool as a reference, mark the corresponding cam bolt head with a line, and then re-inspect using the mark; The adjustment of the front wheel toe angle includes: When the initial toe angle of the front wheel is greater than or equal to the third preset value and the caster angle value cannot be read, the toe angle of the front wheel is pre-adjusted until the caster angle value can be read. The steps of adjusting the chassis height, adjusting the front wheel camber angle, adjusting the caster angle, and adjusting the front wheel toe angle are repeated sequentially. The chassis is provided with steering tie rods on both sides. One side of the steering tie rod is connected to the steering knuckle of the left suspension structure, and the other side of the steering tie rod is connected to the steering knuckle of the right suspension structure. The two steering tie rods are connected by a connecting rod. The adjustment of the front wheel toe angle also includes: after the front wheel toe angle is adjusted, setting the total length difference of the two steering tie rods to be less than or equal to 3mm. The adjustment of the front wheel camber angle includes: Adjust the connecting torque of the connecting bolt of the front bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt of the front bushing according to the second pre-tightening torque, which is in the range of 80Nm to 120Nm. The adjustment of the kingpin caster angle includes: Under the premise that the camber angle of the front wheel is qualified, adjust the caster angle of the kingpin and adjust the connecting torque of the connecting bolt of the rear bushing to the range of 48Nm to 52Nm. After the adjustment is completed, tighten the connecting bolt of the rear bushing to the third preload torque, which is in the range of 80Nm to 120Nm.

6. A vehicle, comprising a chassis, characterized in that, The chassis is adjusted using the chassis adjustment method according to any one of claims 1 to 4.

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