A few leaf spring suspension system for a sightseeing vehicle

Abstract

The application provides a few-leaf spring suspension system for a sightseeing vehicle, and belongs to the technical field of vehicle suspension parts. The few-leaf spring suspension system for the sightseeing vehicle comprises a main leaf spring assembly, a secondary leaf spring assembly, a fixing assembly, an anti-loosening assembly and a damping vibration reduction assembly. The main leaf spring assembly is provided with a variable cross-section section in the middle, and the thickness of the variable cross-section section gradually decreases from the center to both ends. The length of the secondary leaf spring assembly is smaller than that of the main leaf spring assembly, and the secondary leaf spring assembly is fixedly connected with the main leaf spring assembly through a center bolt. The fixing assembly is arranged at both ends of the main leaf spring assembly, and the anti-loosening assembly is arranged in the fixing assembly. The damping vibration reduction assembly comprises a high-frequency damper, a medium-frequency damper and a low-frequency damper. The application can solve the problem of insufficient damping performance of the few-leaf spring suspension system for the sightseeing vehicle in the prior art.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vehicle suspension parts, and in particular relates to a sightseeing vehicle leaf spring suspension system. BACKGROUND

[0002] As an important part of urban rail transit, sightseeing vehicles play an important role in urban tourism. Compared with ordinary passenger cars, sightseeing vehicles not only need to meet the general requirements of passenger performance, but also need to have good mechanical performance and comfort. Among them, the suspension system, as a key component for carrying the weight of the vehicle body and ensuring the safety and comfort of the vehicle, is particularly important in the design of sightseeing vehicles.

[0003] Traditional sightseeing vehicles use multi-leaf spring suspension systems, which have the characteristics of complex structure and high cost. With the progress of technology, leaf spring suspension systems have gradually become the mainstream choice for sightseeing vehicle suspension systems due to their simple structure, light weight, and low cost. However, due to the limited damping performance of the leaf spring suspension system, there are still some problems in actual application.

[0004] Firstly, the vibration characteristics of the leaf spring body itself are difficult to meet the damping requirements of the full frequency band. Due to its high stiffness, the natural frequency is generally high, and it cannot effectively absorb low-frequency vibrations. Moreover, when subjected to high-frequency excitation, the flexural deformation of the leaf spring itself will also cause a large acceleration response, causing discomfort to passengers.

[0005] Secondly, the connection method between the leaf spring and the vehicle body will also affect the damping effect of the suspension system. Traditional rigid connection is easy to cause local stress concentration, while flexible connection is difficult to ensure position stability. Therefore, how to balance between rigid and flexible connection characteristics has become a problem that needs to be solved.

[0006] Thirdly, the selection of dampers in the suspension system is also crucial. Since sightseeing vehicles need to consider both ride comfort and driving stability, a single damping characteristic cannot meet the needs of all working conditions. Therefore, the design scheme of adjustable or multi-stage damping has become a hot research topic.

[0007] In summary, the leaf spring suspension system of the existing sightseeing vehicle has the problem of insufficient damping performance. SUMMARY

[0008] Therefore, the present application provides a leaf spring suspension system for a sightseeing vehicle, which can solve the problem of insufficient damping performance of the leaf spring suspension system of the existing sightseeing vehicle.

[0009] The present application is implemented as follows:

[0010] The invention provides a kind of sightseeing car with few leaf spring suspension system, wherein, including main leaf spring assembly, vice steel plate spring assembly, fixed assembly, anti-loosening assembly and damping vibration reduction assembly;The main leaf spring assembly is provided with variable cross-section section in the middle, the thickness of the variable cross-section section gradually decreases from center to both ends;The length of the vice steel plate spring assembly is less than the main leaf spring assembly, and the vice steel plate spring assembly is fixedly connected with the main leaf spring assembly by center bolt;The fixed assembly is arranged at both ends of the main leaf spring assembly, and the anti-loosening assembly is arranged inside the fixed assembly;The damping vibration reduction assembly includes high-frequency damper, medium-frequency damper and low-frequency damper;The high-frequency damper is arranged in the middle of the main leaf spring assembly, the medium-frequency damper is arranged at the front end of the main leaf spring assembly, and the low-frequency damper is arranged at the rear end of the main leaf spring assembly;The damping coefficient of the high-frequency damper is 15000 newton per meter per second, which is used to attenuate vibration above 20 hertz;The damping coefficient of the medium-frequency damper is 10000 newton per meter per second, which is used to attenuate vibration of 5 to 20 hertz;The damping coefficient of the low-frequency damper is 5000 newton per meter per second, which is used to attenuate vibration below 5 hertz.

[0011] The technical effect of the sightseeing car with few leaf spring suspension system provided by the invention is as follows: first, the main leaf spring adopts variable cross-section design, and the thickness gradually decreases from center to both ends. This structure can make the stress distribution more uniform, avoid stress concentration, and improve the service life of the spring. At the same time, by introducing the vice steel plate spring to form a double-layer steel plate spring structure, not only the overall stiffness is increased, but also the contact pressure distribution between the main and vice springs is optimized, further improving the damping performance.

[0012] Secondly, the suspension system adopts a three-section damper (high-frequency, medium-frequency and low-frequency) design scheme. By reasonably determining the installation position of each damper, they can effectively attenuate vibrations of different frequency bands, avoiding the occurrence of resonance phenomenon, thereby ensuring the damping effect in the full frequency band.

[0013] Thirdly, a series of measures are taken in the installation of the fixed assembly and the damper. On the one hand, flexible rubber gaskets and U-shaped clamping plates are used for connection, which not only ensures the positional stability, but also effectively isolates the direct contact between metals, reducing local stress concentration. On the other hand, by optimizing the contact area relationship between the damper mounting seat and the main leaf spring, sufficient load-carrying capacity is ensured to prevent premature wear and failure.

[0014] In summary, the invention has made targeted optimization for the deficiencies in the prior art under the premise of ensuring the overall damping performance of the sightseeing car suspension system, and has made obvious progress in structure design, connection method and damping characteristics, solving the problem of insufficient damping performance of the existing sightseeing car few leaf spring suspension system.

[0015] On the basis of the above technical solutions, the few-leaf spring suspension system for a sightseeing vehicle can be further improved as follows:

[0016] The main steel plate spring assembly includes a main spring body, main spring eyes, and a reinforcing pad plate, the main spring eyes are arranged at both ends of the main spring body, and the reinforcing pad plate is fixed at the connection position of the main spring body and the main spring eyes; the variable cross-section section is located at the middle part of the main spring body, and the length accounts for 30-40% of the total length of the main spring body.

[0017] Further, the auxiliary steel plate spring assembly includes an auxiliary spring body and a center positioning sleeve, the auxiliary spring body has an arc structure, and the center positioning sleeve is fixed at the middle part of the auxiliary spring body; the two ends of the auxiliary spring body abut against the main steel plate spring assembly to form a double-layer steel plate spring structure.

[0018] Further, the fixing assembly includes a fixing seat, a rubber pad plate, and a U-shaped clamping plate, the fixing seat has a square structure, the inner side is provided with the rubber pad plate, the rubber pad plate abuts against the main steel plate spring assembly, and the U-shaped clamping plate is sleeved outside the main steel plate spring assembly and is fixedly connected with the fixing seat through a connecting bolt assembly.

[0019] Further, the high-frequency damper includes a high-frequency damping cylinder, a high-frequency damping piston, and high-frequency damping oil, the high-frequency damping cylinder is provided with a high-frequency damping cavity, the high-frequency damping cavity is filled with the high-frequency damping oil, and the high-frequency damping piston penetrates through the high-frequency damping cavity; a high-frequency damping hole is formed in the high-frequency damping piston, and the diameter of the high-frequency damping hole is 2 mm.

[0020] Further, the medium-frequency damper includes a medium-frequency damping cylinder, a medium-frequency damping piston, and medium-frequency damping oil, the medium-frequency damping cylinder is provided with a medium-frequency damping cavity, the medium-frequency damping cavity is filled with the medium-frequency damping oil, and the medium-frequency damping piston penetrates through the medium-frequency damping cavity; a medium-frequency damping hole is formed in the medium-frequency damping piston, and the diameter of the medium-frequency damping hole is 3 mm.

[0021] Further, the low-frequency damper includes a low-frequency damping cylinder, a low-frequency damping piston, and low-frequency damping oil, the low-frequency damping cylinder is provided with a low-frequency damping cavity, the low-frequency damping cavity is filled with the low-frequency damping oil, and the low-frequency damping piston penetrates through the low-frequency damping cavity; a low-frequency damping hole is formed in the low-frequency damping piston, and the diameter of the low-frequency damping hole is 4 mm.

[0022] Further, the connecting bolt assembly includes a first connecting bolt and a second connecting bolt, the first connecting bolt is arranged on both sides of the fixing seat and penetrates through the main leaf spring assembly; the second connecting bolt is arranged in the middle of the U-shaped clamping plate and is connected with the anti-loosening assembly.

[0023] The anti-loosening assembly includes a sliding mechanism, a pressing mechanism and an operating mechanism; the sliding mechanism is arranged inside the U-shaped clamping plate, the pressing mechanism is connected with the sliding mechanism and the second connecting bolt, and the operating mechanism is fixed to the outer end of the pressing mechanism; the sliding mechanism includes a sliding groove body and a sliding block assembly, the sliding groove body is arranged in the inner wall of the U-shaped clamping plate, and the sliding block assembly is arranged in the sliding groove body in a sliding mode; the sliding block assembly includes two symmetrical sliding blocks which are fixedly connected through a connecting ring.

[0024] The high-frequency damper, the medium-frequency damper and the low-frequency damper are all fixedly connected with the main leaf spring assembly through a damper mounting seat, the damper mounting seat is connected with the main leaf spring assembly through high-strength bolts; a rubber vibration isolation pad is arranged between the damper mounting seat and the main leaf spring assembly, so as to prevent metal contact between the damper and the main leaf spring assembly.

[0025] In order to better ensure the damping effect of the few-leaf spring suspension system of the sightseeing vehicle, the geometric relationship between the plurality of components is limited through a relationship limiting equation group, and the relationship limiting equation group is described in detail as follows:

[0026] 1. The thickness gradient relationship of the variable cross-section section of the main leaf spring assembly:

[0027]

[0028] In the formula, h(x) is the thickness at a distance x from the center point, with the unit of millimeter; h0 is the maximum thickness of the center point, with the value range of 12-15 millimeters; L is the half length of the variable cross-section section, with the value range of 200-250 millimeters; a is the thickness change rate coefficient, with the value range of 0.3-0.4; x is the distance from the center point, with the value range of 0-L millimeters.

[0029] 2. The contact pressure distribution relationship of the main and auxiliary leaf springs:

[0030]

[0031] In the formula, p(x) is the contact pressure at a distance x from the center point, with the unit of megapascal; p0 is the maximum contact pressure of the center point, with the value range of 3-5 megapascal; β is the pressure attenuation coefficient, with the value range of 0.01-0.015; F is the pre-tightening force, with the value range of 2000-3000 newtons; r c is the contact radius, with the value range of 25-30 millimeters.

[0032] 3. Optimal spacing relationship of three dampers:

[0033]

[0034] where d1, d2, d3 are the distances from the high-frequency, medium-frequency, and low-frequency dampers to the center point, respectively, in millimeters; ω1, ω2, ω3 are the characteristic frequencies of the respective dampers, respectively, taking 20 Hz, 12.5 Hz, and 5 Hz.

[0035] 4. Contact area relationship between the damper mounting seat and the main steel plate spring:

[0036]

[0037] where A is the contact area, in square millimeters; A is the cross-sectional area of the main steel plate spring, in square millimeters; γ is the area proportionality coefficient, taking a value in the range of 1.2-1.5; F is the damping force, in Newton; F is the spring force, in Newton. c b d s

[0038] 5. Compression amount and pressure relationship of the rubber pad:

[0039] δ = k1P + k2P + k3ln(1 + P); 2

[0040] where δ is the compression amount, in millimeters; P is the pressure, in mega-Pascal; k1, k2, k3 are material characteristic coefficients, obtained through experiments.

[0041] The experimental steps are as follows:

[0042] 1. Perform compression test on the rubber pad on a universal material testing machine;

[0043] 2. Record the compression amount data points (P i , δ i ) under different pressures;

[0044] 3. Obtain the coefficients k1, k2, k3 by least squares fitting.

[0045] 6. Contact stress distribution of the U-shaped clamp plate and the fixing seat:

[0046]

[0047] ​​​​​In the formula, σ (r) is the contact stress at the radial distance r, with the unit of megapascal; σ 0 is the maximum central stress, with the value range of 150-200 megapascal; τ 0 is the shear stress, with the value range of 30-50 megapascal; R is the radius of the contact area, with the unit of millimeter; and r is the radial distance of the calculation point, with the unit of millimeter.

[0048] Equation principle explanation:

[0049] 1. The variable cross-section thickness equation adopts a quadratic function form, because: the quadratic function can ensure smooth transition at the end; the stress distribution law conforms to the parabolic characteristics; and the manufacturing process is easy to realize.

[0050] 2. The contact pressure distribution equation contains two terms: the exponential term describes the pressure decay law with distance; and the Gaussian term describes the local pressure distribution caused by the pre-tightening force; the superposition of the two terms is more in line with the actual contact state.

[0051] 3. The damper spacing relationship is based on the vibration transmission principle: the frequency square root proportional relationship is derived from the wave equation; the vibration in each frequency band can be effectively attenuated; and the resonance phenomenon is avoided.

[0052] 4. The contact area relationship adopts a power function form: the 0.75 power is derived from the Hertz contact theory; the nonlinear effect of load on the contact area is considered; and the coefficient γ is introduced to compensate for the installation error.

[0053] 5. The rubber compression relationship contains three terms: the linear term represents the initial elastic deformation; the quadratic term represents the large deformation effect; and the logarithmic term represents the material hardening characteristics.

[0054] 6. The contact stress distribution equation: the first term is derived from the Hertz contact theory; the second term considers the influence of shear stress; and the complex stress state is more accurately described.

[0055] Compared with the prior art, the beneficial effects of the few-leaf spring suspension system for a sightseeing vehicle provided by the application are: first, the main steel plate spring adopts a variable cross-section design, and the thickness gradually decreases from the center to both ends. This structure can make the stress distribution more uniform, avoid stress concentration, and improve the service life of the spring. At the same time, a double-layer steel plate spring structure is formed by introducing a secondary steel plate spring, which not only increases the overall stiffness but also optimizes the contact pressure distribution between the main and secondary springs, further improving the damping performance.

[0056] Secondly, the suspension system adopts a three-section damper (high frequency, medium frequency and low frequency) design scheme. By reasonably determining the installation positions of the dampers, they can effectively attenuate the vibrations of different frequency bands, avoid the occurrence of resonance phenomenon, and thus ensure the damping effect in the full frequency band.

[0057] Thirdly, a series of measures are taken in the installation of the fixed assembly and the damper. On the one hand, the flexible rubber pad and the U-shaped clamping plate are used to ensure the stability of the position and effectively isolate the direct contact between the metals, thereby reducing the local stress concentration. On the other hand, the contact area between the damper mounting seat and the main leaf spring is optimized to ensure sufficient load capacity and prevent premature wear and failure.

[0058] In summary, the present application optimizes the deficiencies in the prior art under the premise of ensuring the overall damping performance of the sightseeing vehicle suspension system, and makes obvious progress in structure design, connection mode and damping characteristics, thereby solving the problem of insufficient damping performance of the sightseeing vehicle leaf spring suspension system in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor under the premise of the drawings.

[0060] Figure 1 Fig. 1 is a structural schematic diagram of a sightseeing vehicle leaf spring suspension system according to the present application.

[0061] In the drawings, the component list represented by each reference numeral is as follows:

[0062] 10, main leaf spring assembly; 11, main spring body; 12, main spring eye; 13, reinforcing pad; 20, auxiliary leaf spring assembly; 21, auxiliary spring body; 22, center positioning sleeve; 30, fixed assembly; 31, fixed seat; 32, rubber pad; 33, U-shaped clamping plate; 40, anti-loosening assembly; 50, damping assembly; 51, high-frequency damper; 511, high-frequency damping cylinder; 512, high-frequency damping piston; 513, high-frequency damping cavity; 52, medium-frequency damper; 521, medium-frequency damping cylinder; 522, medium-frequency damping piston; 523, medium-frequency damping cavity; 53, low-frequency damper; 531, low-frequency damping cylinder; 532, low-frequency damping piston; 533, low-frequency damping cavity; 60, variable cross-section section; 70, connecting bolt assembly; 71, first connecting bolt; 72, second connecting bolt. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application.

[0064] As Figure 1The embodiment of the few-leaf spring suspension system for a sightseeing vehicle is provided by the application, and in the embodiment, a main leaf spring assembly 10, a secondary leaf spring assembly 20, a fixing assembly 30, an anti-loosening assembly 40 and a damping and shock-absorbing assembly 50 are included; a variable cross-section section 60 is arranged in the middle of the main leaf spring assembly, and the thickness of the variable cross-section section gradually decreases from the center to both ends; the length of the secondary leaf spring assembly is less than that of the main leaf spring assembly, and the secondary leaf spring assembly is fixedly connected with the main leaf spring assembly through a center bolt; the fixing assembly is arranged at both ends of the main leaf spring assembly, and the anti-loosening assembly is arranged inside the fixing assembly; the damping and shock-absorbing assembly includes a high-frequency damper 51, a medium-frequency damper 52 and a low-frequency damper 53; the high-frequency damper is arranged in the middle of the main leaf spring assembly, the medium-frequency damper is arranged at the front end of the main leaf spring assembly, and the low-frequency damper is arranged at the rear end of the main leaf spring assembly; the damping coefficient of the high-frequency damper is 15000 N / m / s, and the high-frequency damper is used for attenuating vibrations above 20 Hz; the damping coefficient of the medium-frequency damper is 10000 N / m / s, and the medium-frequency damper is used for attenuating vibrations of 5 to 20 Hz; and the damping coefficient of the low-frequency damper is 5000 N / m / s, and the low-frequency damper is used for attenuating vibrations below 5 Hz.

[0065] In the technical scheme, the main leaf spring assembly includes a main spring body 11, a main spring eye 12 and a reinforcing pad 13, the main spring eye is arranged at both ends of the main spring body, and the reinforcing pad is fixed at the connection position of the main spring body and the main spring eye; the variable cross-section section is located in the middle of the main spring body, and the length of the variable cross-section section accounts for 30 to 40% of the total length of the main spring body.

[0066] Further, in the technical scheme, the secondary leaf spring assembly includes a secondary spring body 21 and a center positioning sleeve 22, the secondary spring body has an arc structure, and the center positioning sleeve is fixed in the middle of the secondary spring body; both ends of the secondary spring body abut against the main leaf spring assembly, and a double-layer leaf spring structure is formed.

[0067] Further, in the technical scheme, the fixing assembly includes a fixing seat 31, a rubber pad 32 and a U-shaped clamp plate 33, the fixing seat has a square structure, the inner side of the fixing seat is provided with the rubber pad, and the rubber pad abuts against the main leaf spring assembly; the U-shaped clamp plate is sleeved outside the main leaf spring assembly and is fixedly connected with the fixing seat through a connecting bolt assembly.

[0068] Further, in the technical scheme, the high-frequency damper includes a high-frequency damping cylinder body 511, a high-frequency damping piston 512 and high-frequency damping oil, the high-frequency damping cylinder body is provided with a high-frequency damping cavity 513, the high-frequency damping cavity is filled with the high-frequency damping oil, and the high-frequency damping piston penetrates through the high-frequency damping cavity; a high-frequency damping hole is arranged on the high-frequency damping piston, and the diameter of the high-frequency damping hole is 2 mm.

[0069] Further, in the above technical solution, the intermediate frequency damper includes an intermediate frequency damping cylinder body 521, an intermediate frequency damping piston 522, and intermediate frequency damping oil, the intermediate frequency damping cylinder body is provided with an intermediate frequency damping cavity 523, the intermediate frequency damping cavity is filled with intermediate frequency damping oil, and the intermediate frequency damping piston penetrates the intermediate frequency damping cavity; the intermediate frequency damping piston is provided with an intermediate frequency damping hole, and the intermediate frequency damping hole has a diameter of 3 mm.

[0070] Further, in the above technical solution, the low-frequency damper includes a low-frequency damping cylinder body 531, a low-frequency damping piston 532, and low-frequency damping oil, the low-frequency damping cylinder body is provided with a low-frequency damping cavity 533, the low-frequency damping cavity is filled with low-frequency damping oil, and the low-frequency damping piston penetrates the low-frequency damping cavity; the low-frequency damping piston is provided with a low-frequency damping hole, and the low-frequency damping hole has a diameter of 4 mm.

[0071] Further, in the above technical solution, the connecting bolt assembly 70 includes a first connecting bolt 71 and a second connecting bolt 72, the first connecting bolt is arranged on both sides of the fixed seat and penetrates the main leaf spring assembly; and the second connecting bolt is arranged in the middle of the U-shaped clamping plate and connected with the anti-loosening assembly.

[0072] In the above technical solution, the anti-loosening assembly includes a sliding mechanism, a pressing mechanism, and an operating mechanism; the sliding mechanism is arranged in the U-shaped clamping plate, the pressing mechanism is connected with the sliding mechanism and the second connecting bolt, and the operating mechanism is fixed to the outer end of the pressing mechanism; the sliding mechanism includes a sliding groove body and a sliding block assembly, the sliding groove body is arranged on the inner wall of the U-shaped clamping plate, and the sliding block assembly is slidingly arranged in the sliding groove body; the sliding block assembly includes two symmetrical sliding blocks, and the sliding blocks are fixedly connected through a connecting ring.

[0073] In the above technical solution, the high-frequency damper, the intermediate frequency damper, and the low-frequency damper are all fixedly connected with the main leaf spring assembly through a damper mounting seat, the damper mounting seat is connected with the main leaf spring assembly through high-strength bolts, and a rubber vibration isolation pad is arranged between the damper mounting seat and the main leaf spring assembly to prevent metal contact between the damper and the main leaf spring assembly.

[0074] The main leaf spring assembly adopts a variable cross-section design, the middle part has a larger thickness, and the two ends gradually thin. This structure can make the stress distribution of the spring more uniform, avoid stress concentration, and improve the service life. The thickness change conforms to a quadratic function relationship. In the above technical solution, the main leaf spring assembly adopts a variable cross-section design, the middle part has a larger thickness, and the two ends gradually thin. This structure can make the stress distribution of the spring more uniform, avoid stress concentration, and improve the service life. The thickness change conforms to a quadratic function relationship.

[0075] The main leaf spring assembly and the auxiliary leaf spring assembly are connected by a center bolt to form a double-layer leaf spring structure. The contact pressure distribution can be described as where p(x) is the contact pressure at a distance x from the center point, with units of megapascal; p0 is the maximum contact pressure at the center point, with a value range of 3-5 megapascal; β is the pressure decay coefficient, with a value range of 0.01-0.015; F is the pre-tightening force, with a value range of 2000-3000 Newton; r c is the contact radius, with a value range of 25-30 millimeters. This formula contains two terms: the exponential term describes the pressure decay law with distance; the Gaussian term describes the local pressure distribution caused by the pre-tightening force, and the superposition of the two terms can more accurately describe the actual contact state.

[0076] The suspension system uses a three-section damper, which is a high-frequency, medium-frequency, and low-frequency damper. Their installation positions should satisfy the relationship where d1, d2, and d3 are the distances from the center point to the high-frequency, medium-frequency, and low-frequency dampers, respectively, with units of millimeters; ω1, ω2, and ω3 are the characteristic frequencies of each damper, respectively taking 20 Hz, 12.5 Hz, and 5 Hz. This spacing relationship is derived from the vibration transmission principle, which can ensure that the vibrations in each frequency band are effectively attenuated, avoiding resonance phenomena.

[0077] The contact area between the damper mounting seat and the main leaf spring should satisfy the relationship where A c is the contact area, with units of square millimeters; A b is the cross-sectional area of the main leaf spring, with units of square millimeters; γ is the area proportionality coefficient, with a value range of 1.2-1.5; F d is the damping force, with units of Newton; F s is the spring force, with units of Newton. This relationship is derived from the Hertz contact theory, taking into account the nonlinear effect of load on the contact area, and introducing the coefficient γ to compensate for installation errors.

[0078] The relationship between the compression amount and the pressure of the rubber pad in the fixed assembly is δ = k1P + k2P 2 + k3ln(1+P). Through compression tests on the universal material testing machine, the compression data points (P i , δ i ) under different pressures are recorded, and the coefficients k1, k2, and k3 are obtained by least squares fitting. This relationship contains three terms: the linear term represents the initial elastic deformation, the quadratic term represents the large deformation effect, and the logarithmic term represents the material hardening characteristics.

[0079] Finally, the contact stress distribution between the U-shaped clamp plate and the fixed seat can be described as Wherein, σ (r) is the contact stress at the radial distance r, unit is megapascal; σ0 is the central maximum stress, the value range is 150-200 megapascal; τ0 is the shear stress, the value range is 30-50 megapascal; R is the contact area radius, unit is millimeter; r is the radial distance of the calculation point, unit is millimeter.The first term of this formula is derived from the Hertz contact theory, the second term considers the influence of shear stress, which can more accurately describe the complex stress state.

[0080] Embodiment 1:

[0081] This embodiment focuses on the main components structure, material and manufacturing process of the few leaf spring suspension system of the sightseeing vehicle, and makes a detailed description.

[0082] 1. Main leaf spring assembly

[0083] The main leaf spring assembly is the core component of the suspension system, and its structure design directly affects the damping performance of the whole system. In order to meet the requirements of the sightseeing vehicle on full-band damping, this embodiment adopts variable cross-section design.

[0084] The main spring body is made of high-quality spring steel plate (60Si2Mn) with a thickness of 12-15 millimeters. The middle part of the steel plate is thicker, and the two ends are gradually thinned, meeting the thickness variation law of . Among them, h0 takes 14 millimeters, L takes 225 millimeters, and α takes 0.35. The thickness of this quadratic function gradually changes, which can ensure the smooth transition of the two ends of the spring, avoid stress concentration, and improve the service life.

[0085] Spring eyes are welded at both ends of the spring body for connection with the frame. In order to enhance the strength of the spring eye, a reinforcing pad (45# steel, thickness 6 millimeters) is also provided at the connection between the spring body and the spring eye. The reinforcing pad is fixed on the spring body by welding process, ensuring the reliability of the overall structure.

[0086] 2. Auxiliary leaf spring assembly

[0087] The auxiliary leaf spring assembly is made of 60Si2Mn spring steel plate with a thickness of 10 millimeters. Its body adopts arc design, showing a "U" shape structure with a length slightly smaller than that of the main leaf spring assembly. The middle part of the spring body is fixed with a center positioning sleeve through welding process, which is used to cooperate with the center bolt of the main leaf spring assembly to form a double-layer spring structure.

[0088] The two ends of the auxiliary leaf spring contact with the upper surface of the main leaf spring assembly, and the force transmission is realized through the pre-tightening force. This double-layer leaf spring structure not only can improve the overall stiffness, but also can optimize the contact pressure distribution between the main and auxiliary springs, thereby further improving the damping performance of the whole suspension system.

[0089] 3. Fixing assembly

[0090] The fixing assembly is mainly composed of a fixing base, a rubber pad and a U-shaped clamping plate. The fixing base is made of 45# steel and has a square structure. A rubber pad with a thickness of 15 mm (rubber hardness 80°) is arranged on the inner side and directly contacts the main leaf spring assembly. The U-shaped clamping plate is also made of 45# steel and is fixed to the fixing base by connecting bolts to clamp the main leaf spring assembly.

[0091] This flexible connection mode can effectively absorb the displacement deformation of the spring and avoid local stress concentration problems that may occur under rigid connection. At the same time, the damping characteristics of the rubber pad can further improve the overall damping performance. The pre-tightening force between the fixing base, the rubber pad and the U-shaped clamping plate directly determines the stiffness characteristics of the system, which needs to be optimized according to the actual working conditions.

[0092] 4. Anti-loosening assembly

[0093] The anti-loosening assembly is arranged inside the U-shaped clamping plate and mainly composed of a sliding mechanism, a pressing mechanism and an operating mechanism. The sliding mechanism includes a sliding groove body arranged on the inner wall of the U-shaped clamping plate and two symmetrical sliding blocks slidingly arranged therein. This sliding structure can ensure that the U-shaped clamping plate can make a small displacement along the axis of the main leaf spring assembly, effectively preventing loosening caused by factors such as temperature changes and vibrations.

[0094] The pressing mechanism connects the sliding blocks with a second connecting bolt fixed in the middle of the U-shaped clamping plate. By adjusting the pre-tightening force of the bolt, the stress state of the sliding mechanism can be controlled, further enhancing the anti-loosening performance. The operating mechanism is arranged at the outer end of the pressing mechanism, through which the working personnel can adjust the pre-tightening force to meet the needs of different working conditions.

[0095] Through the design of the above anti-loosening assembly, not only the position stability of the suspension system during long-term use can be ensured, but also the system can be adjusted at any time according to the actual working conditions, improving the reliability of the entire system.

[0096] 5. Damping assembly

[0097] The damping assembly includes a high-frequency damper, a medium-frequency damper and a low-frequency damper, which are installed at the middle, front end and rear end of the main leaf spring assembly, respectively. This multi-stage damping design can effectively cover the full-band vibration of the sightseeing vehicle under various working conditions.

[0098] The internal structure of the high-frequency damper is as follows: the cylinder body is cast with 45# steel and is equipped with a high-frequency damping cavity with a diameter of 80 mm; the piston is made of 45# steel and has a high-frequency damping hole with a diameter of 2 mm on it, which cooperates with the high-frequency damping oil in the cavity (viscosity 0.3 Pa·s) to provide a damping coefficient of 15,000 Newtons per meter per second, which is used to attenuate high-frequency vibrations above 20 Hz.

[0099] The structure of the medium-frequency damper is similar. The cylinder diameter is 90 mm, and there is a medium-frequency damping hole with a diameter of 3 mm on the piston. Together with the medium-frequency damping oil (viscosity 0.5 Pa·s), it provides a damping coefficient of 10,000 Newtons per meter per second, which is used to attenuate medium-frequency vibrations of 5-20 Hz.

[0100] The low-frequency damper cylinder has a diameter of 100 mm, and the piston is provided with a low-frequency damping hole with a diameter of 4 mm. Together with the low-frequency damping oil (viscosity 0.8 Pa·s), it provides a damping coefficient of 5000 Newtons per meter per second, which is used to attenuate low-frequency vibrations below 5 Hz.

[0101] The installation positions of the three dampers meet the requirements , where d1, d2, and d3 are the distances from the high-frequency, mid-frequency, and low-frequency dampers to the center point, respectively, and ω1, ω2, and ω3 are their characteristic frequencies, 20 Hz, 12.5 Hz, and 5 Hz, respectively. This spacing design ensures effective attenuation of vibrations in each frequency band, preventing resonance.

[0102] Furthermore, the mounting bases for all three dampers are made of 45# steel and connected to the main leaf spring assembly via high-strength bolts. A 5mm-thick rubber isolation pad is placed between the mounting base and the spring to isolate metal contact and prevent stress concentration.

[0103] Through the above-mentioned structural design and material selection, the sightseeing vehicle with a small leaf spring suspension system in this embodiment not only ensures the overall vibration reduction performance, but also further optimizes the strength, reliability and economy of each component, laying a solid foundation for the widespread application of sightseeing vehicles.

[0104] Example 2:

[0105] This embodiment focuses on analyzing the relationship between the various components of the leaf spring suspension system for sightseeing vehicles and provides specific numerical ranges to ensure that the entire system operates in an optimal state.

[0106] 1. Variable cross-section design of the main leaf spring assembly

[0107] The thickness variation of the main leaf spring assembly satisfies After analysis, calculation and experimental verification, the value ranges of the parameters in the formula are as follows: h0 = 14 mm, L = 225 mm, α = 0.35.

[0108] This thickness gradient in the form of a quadratic function ensures smooth transition at both ends of the spring, makes stress distribution more uniform, avoids stress concentration, and improves service life. The center thickness h0 is 14 mm, which takes into account the feasibility of manufacturing process under the premise of meeting the overall stiffness requirements. The length of the variable cross-section segment L is 225 mm, accounting for about 40% of the total length of the spring body, which can maximize the optimization effect. The thickness change rate coefficient a is 0.35, which reduces the thickness of both ends to 65% and 85% of the center thickness, respectively, achieving a reasonable transition.

[0109] 2. Contact pressure distribution of main and auxiliary leaf springs

[0110] The contact pressure distribution between the main leaf spring assembly and the auxiliary leaf spring assembly can be described by Through analysis and testing, the value range of each parameter is as follows: p0 = 4 MPa, β = 0.012, F = 2500 N, r c = 28 mm.

[0111] The first exponential function describes the law of contact pressure decay with distance, p0 = 4 MPa represents the maximum contact pressure at the center point; the pressure decay coefficient β = 0.012 reduces the pressure at a distance of 100 mm from the center to 1 / e of the initial value. The second Gaussian function reflects the local pressure distribution caused by the pre-tightening force F = 2500 N, with a contact radius r c = 28 mm. This pressure distribution is beneficial to optimizing the force transmission characteristics between the main and auxiliary springs, further improving the damping performance.

[0112] 3. Installation position of three-stage damper

[0113] The installation positions of the three dampers (high frequency, medium frequency, and low frequency) should satisfy the relationship According to the vibration characteristics of the system, the characteristic frequencies of each damper are ω1 = 20 Hz, ω2 = 12.5 Hz, and ω3 = 5 Hz, respectively.

[0114] Through calculation, it can be obtained that the distance of the high-frequency damper from the center point d1 = 150 mm, the distance of the medium-frequency damper from the center point d2 = 240 mm, and the distance of the low-frequency damper from the center point d3 = 400 mm. This spacing relationship can ensure effective attenuation of vibrations in each frequency band and avoid resonance.

[0115] 4. Contact area between damper mounting seat and main leaf spring

[0116] The contact area between the damper mounting seat and the main leaf spring should satisfy the relationship According to the test data, γ = 1.35 is taken, where A b= 3600 square millimeters is the cross-sectional area of the main leaf spring, F d = 3000 Newton is the damping force, F s = 30000 Newton is the spring force.

[0117] Through calculation, the required contact area A c = 800 square millimeters. This contact area relationship can not only meet the requirement of carrying capacity, but also effectively reduce the contact stress to avoid premature wear. Meanwhile, a 5-millimeter-thick rubber vibration isolation pad is arranged between the damper mounting seat and the main leaf spring to further isolate the metal contact and prevent stress concentration.

[0118] 5. Relationship between compression amount and pressure of the rubber pad

[0119] The relationship between the compression amount δ and the pressure P of the rubber pad in the fixed assembly can be described by δ = k1P + k2P 2 + k3ln(1 + P). Through experimental fitting, the values of the coefficients are as follows: k1 = 0.05, k2 = 0.002, and k3 = 0.03.

[0120] This relationship formula containing linear, quadratic, and logarithmic terms can accurately reflect the nonlinear mechanical properties of rubber materials under large deformation conditions. According to the calculation, when the pressure is 4 megapascals, the compression amount of the rubber pad is about 8 millimeters. This moderate compression amount can not only meet the stiffness requirement of the system, but also fully exert the damping properties of rubber to further improve the damping performance.

[0121] 6. Contact stress distribution between the U-shaped clamp plate and the fixed seat

[0122] The contact stress distribution between the U-shaped clamp plate and the fixed seat can be described by According to the analysis calculation, σ0 = 180 megapascals, τ0 = 40 megapascals, and R = 90 millimeters.

[0123] The first term represents the radial stress distribution, with the maximum stress σ0 = 180 megapascals at the center, which decreases in a parabolic manner with the increase of the radius r; the second term describes the tangential stress distribution, with τ0 = 40 megapascals. The contact area radius R = 90 millimeters can ensure that the contact stress is within the allowable range, avoiding failures caused by local stress concentration.

[0124] Through the relationship between the above components, the few-leaf spring suspension system for the sightseeing vehicle in this embodiment further optimizes the structural strength, reliability, and economy under the premise of meeting the overall damping performance, ensuring stable and reliable operation of the system under various working conditions.

[0125] Specifically, the principle of the present invention is: the core technical principles of the sightseeing vehicle suspension system with fewer leaf springs proposed by the present invention can be summarized as follows:

[0126] 1. Variable cross-section main leaf spring design. The main leaf spring has a larger thickness in the middle and gradually becomes thinner at both ends. This structure can make the spring stress distribution more uniform, avoid stress concentration, and increase service life. The variation of thickness along the length is described by a quadratic function, where h(x) is the thickness at a distance x from the center, h0 is the maximum thickness at the center, L is the half-length of the variable-section segment, and α is the coefficient of thickness variation. This quadratic function ensures a smooth transition at the end, conforming to the parabolic characteristics of actual stress distribution, while also facilitating manufacturing.

[0127] 2. Double-layer leaf spring structure. The main leaf spring assembly and the auxiliary leaf spring assembly are connected by a central bolt to form a double-layer leaf spring structure. This design not only increases the overall stiffness, but also optimizes the contact pressure distribution between the main and auxiliary springs. The contact pressure can be It contains two items: the exponential term describes the pressure attenuation law with distance, and the Gaussian term describes the local pressure distribution caused by the preload. The superposition of the two items can more accurately reflect the actual contact state. Reasonable adjustment of these parameters, such as the maximum center pressure p0, pressure attenuation coefficient β, preload F and contact radius r c Etc., can further improve the coordination of the main and auxiliary springs, thereby optimizing the overall vibration reduction effect.

[0128] 3. Multi-stage damper design. The suspension system uses three-stage dampers (high frequency, medium frequency and low frequency). By reasonably determining the installation position of each damper, they can effectively attenuate vibrations in different frequency bands. The installation position should meet , where d1, d2, and d3 are the distances from each damper to the center point, and ω1, ω2, and ω3 are their characteristic frequencies. This spacing relationship, derived from the principle of vibration transmission, effectively attenuates vibrations across all frequencies, avoiding resonance and ensuring full-band vibration reduction.

[0129] 4. Coupling design of damper and spring. In terms of damper installation, by optimizing the contact area relationship between the damper mounting seat and the main leaf spring, that is, Ensures sufficient load-bearing capacity to prevent premature wear and failure. c is the contact area, A b is the spring cross-sectional area, γ is the area proportional coefficient, F d is the damping force, F sThe relationship is derived from Hertz contact theory, and the nonlinear effect of load on contact area is considered. The coefficient γ is introduced to compensate for the error in the installation process. At the same time, a rubber vibration isolation pad is arranged between the damper and the spring, which effectively isolates the direct contact between metals and avoids local stress concentration.

[0130] 5. Flexible fixing assembly design. The fixing assembly adopts a flexible connection mode of rubber pads and U-shaped clamping plates. Compared with rigid connection, this design not only can effectively absorb displacement deformation, but also can fully play the damping characteristics of rubber, thereby further improving the overall damping performance. The relationship between the compression amount and the pressure of the rubber pad is δ=k1P+k2P+k3ln(1+P), and the coefficients k1, k2 and k3 are obtained by experimental fitting. This relationship can accurately describe the nonlinear mechanical properties of rubber. 2

[0131] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A leaf-spring-less suspension system for a sightseeing vehicle, characterized in that: The vehicle comprises a main leaf spring assembly, an auxiliary leaf spring assembly, a fixing assembly, an anti-loosening assembly and a damping and vibration reduction assembly; a variable cross-section section is provided in the middle of the main leaf spring assembly, and the thickness of the variable cross-section section gradually decreases from the center to both ends; the length of the auxiliary leaf spring assembly is smaller than that of the main leaf spring assembly, and the auxiliary leaf spring assembly is fixedly connected to the main leaf spring assembly by a central bolt; the fixing assembly is arranged at both ends of the main leaf spring assembly, and the anti-loosening assembly is arranged inside the fixing assembly; the damping and vibration reduction assembly comprises a high-frequency damper, a medium-frequency damper, and a The high-frequency damper is arranged in the middle of the main leaf spring assembly, the medium-frequency damper is arranged at the front end of the main leaf spring assembly, and the low-frequency damper is arranged at the rear end of the main leaf spring assembly; the damping coefficient of the high-frequency damper is 15,000 Newtons per meter per second, which is used to attenuate vibrations above 20 Hz; the damping coefficient of the medium-frequency damper is 10,000 Newtons per meter per second, which is used to attenuate vibrations from 5 to 20 Hz; the damping coefficient of the low-frequency damper is 5,000 Newtons per meter per second, which is used to attenuate vibrations below 5 Hz.

2. The sightseeing vehicle with a leaf-less spring suspension system according to claim 1, characterized in that: The main leaf spring assembly includes a main spring body, a main spring eye and a reinforcing plate. The main spring eye is arranged at both ends of the main spring body, and the reinforcing plate is fixed at the connection between the main spring body and the main spring eye; the variable cross-section section is located in the middle of the main spring body, and its length accounts for 30 to 40% of the total length of the main spring body.

3. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 2, characterized in that: The auxiliary leaf spring assembly includes an auxiliary spring body and a center positioning sleeve. The auxiliary spring body is an arc-shaped structure, and the center positioning sleeve is fixed to the middle of the auxiliary spring body. The two ends of the auxiliary spring body abut against the main leaf spring assembly to form a double-layer leaf spring structure.

4. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 3, characterized in that: The fixing assembly includes a fixing seat, a rubber pad and a U-shaped clamp. The fixing seat has a square structure and a rubber pad is provided on the inner side. The rubber pad is tightly pressed against the main leaf spring assembly. The U-shaped clamp is sleeved on the outer side of the main leaf spring assembly and is fixedly connected to the fixing seat by a connecting bolt assembly.

5. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 4, characterized in that: The high-frequency damper includes a high-frequency damping cylinder, a high-frequency damping piston and high-frequency damping oil. The high-frequency damping cylinder is provided with a high-frequency damping chamber, the high-frequency damping chamber is filled with the high-frequency damping oil, and the high-frequency damping piston passes through the high-frequency damping chamber; the high-frequency damping piston is provided with a high-frequency damping hole, and the diameter of the high-frequency damping hole is 2 mm.

6. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 5, characterized in that: The intermediate frequency damper includes an intermediate frequency damping cylinder, an intermediate frequency damping piston and an intermediate frequency damping oil. The intermediate frequency damping cylinder is provided with an intermediate frequency damping cavity, the intermediate frequency damping cavity is filled with the intermediate frequency damping oil, and the intermediate frequency damping piston passes through the intermediate frequency damping cavity. An intermediate frequency damping hole is provided on the intermediate frequency damping piston, and the diameter of the intermediate frequency damping hole is 3 mm.

7. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 6, characterized in that: The low-frequency damper includes a low-frequency damping cylinder, a low-frequency damping piston and low-frequency damping oil. A low-frequency damping chamber is provided in the low-frequency damping cylinder, the low-frequency damping chamber is filled with the low-frequency damping oil, and the low-frequency damping piston passes through the low-frequency damping chamber. A low-frequency damping hole is provided on the low-frequency damping piston, and the diameter of the low-frequency damping hole is 4 mm.

8. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 4, characterized in that: The connecting bolt assembly includes a first connecting bolt and a second connecting bolt. The first connecting bolt is arranged on both sides of the fixing seat and passes through the main leaf spring assembly; the second connecting bolt is arranged in the middle of the U-shaped clamping plate and is connected to the anti-loosening assembly.

9. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 1, characterized in that: The anti-loosening assembly includes a sliding mechanism, a clamping mechanism and an operating mechanism; the sliding mechanism is arranged inside the U-shaped clamp, the clamping mechanism connects the sliding mechanism and the second connecting bolt, and the operating mechanism is fixed to the outer end of the clamping mechanism; the sliding mechanism includes a slide groove body and a slider assembly, the slide groove body is opened on the inner wall of the U-shaped clamp, and the slider assembly is slidably arranged in the slide groove body; the slider assembly includes two symmetrically arranged sliding blocks, and the sliding blocks are fixedly connected by a connecting ring.

10. The leaf-spring-less suspension system for a sightseeing vehicle according to claim 1, characterized in that: The high-frequency damper, medium-frequency damper and low-frequency damper are all fixedly connected to the main leaf spring assembly through a damper mounting seat, and the damper mounting seat is connected to the main leaf spring assembly through high-strength bolts; a rubber vibration isolation pad is provided between the damper mounting seat and the main leaf spring assembly to prevent metal contact between the damper and the main leaf spring assembly.

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