Suspension Device Type and Fracture Analysis Yang Chengxian Abstract This article analyzed the causes of the breakage of the steel plate suspension device in the driving performance test of the new product of the automobile excavator. The stress experienced by the leaf spring was calculated under various conditions. Analyzes the elasticity of the elasticity of the leaf spring and the elastic characteristics of the oil and gas suspension. It points out the analysis of the breakage of the car's mining excavator's suspension. The newly-developed car excavator has a capacity of 2,1 bucket and the maximum speed. The training meets the requirement of driving and degree. , The machine has selected a leaf spring suspension form of a red rock truck with a load capacity of 2, 7 steel plates for the front axle, 9 steel plates for the rear axle, 121 pieces of bolts for each thickness, and the truss connection through the bracket 4 excavator. . 1 After the completion of the trial flight, 5000 reliability tests were performed on the two prototypes. At the same time, the two prototypes were tested on different roads such as cement, asphalt, mud, mud, bumps and other roads. The top speed of the test was 53. The average speed was 41.51. When the prototype was running at 560, the left and right front leaf springs were broken. As the prototype traveled 854.5, the left rear leaf spring broke. The 12th sample leaf spring breaks position 1 in the middle. 1 Flash-like analysis of leaf spring breakage The fractured parts of the leaf springs of both prototypes are in the cross-section of the rolling ear, and the shape of the crack is also similar. The metallographic and strength analysis and 1 art core of the village metallurgy were carried out on the broken leaf springs. All of them met the index requirements of the 61 steel. The allowable bending stress was 450, and the maximum deformation stress should be 700. Therefore, the reason for the spring break was not The question of process materials, from the analysis of the shape of the cracks, can be initially considered as a failure of fatigue fracture. 1.1 Qualitative analysis Leaf spring is directly used as a steel bullet for Hongyan Automobile with a carrying capacity of 2,1. It is safe and reliable for use on trucks, but less than 10001 occurs when auto-type excavators are used less than 501. fracture. Because the working conditions of auto excavators and trucks are different, the load on leaf springs of trucks is not fully loaded at all times, and the working conditions of auto excavators are much more complicated than the conditions of trucks, and the road conditions used are different. The working environment is even harsher, and the impact on the steel plate magazine is much larger than that of the truck. The qualitative analysis of the reason for the rupture of the leaf spring is as follows: 1 Full load or overload for a long period of time, making the sodium plate spring too large Bending stress. The fatigue resistance of the steel plate decreases and the fracture breaks. In the case of emergency braking and maximum traction force, the steel plate is subjected to bending and stretching due to the action of braking force and inertial force. The combined effect of the two stresses greatly exceeds the vertical bending stress of the steel plate and significantly increases the load on the steel plate. Vertical vibration. Due to the poor road conditions of an automotive excavator, vertical vibration is generated due to unevenness, so that the amplitude of the leaf spring is increased, the vibration frequency is increased, bending stress is increased, and fatigue is accelerated. Raw side slip, centrifugal inertial force, large, increase the load of the inner steel plate, 1.2 stress juice escort analysis of the car-type excavator leaf spring should be calculated strength analysis. It is not possible to directly use the leaf spring of my heavy steamer. 10.2.1 The action of the spring force in the longitudinal direction of the leaf spring is the maximum. 1 During the emergency braking, the load on the front leaf spring is the largest. The steam excavator adopts the symmetrical leaf spring structure. . Force 1 is small. The reaction force of the fulcrum 5 is the horizontal reaction force that A acts on the steel plate spring point; the distance from the hc spring fixing point to the road surface; the load of the front axle 9 Du Pr system when the front axle redistribution coefficient Gki is full at the time of Mn braking. Dynamics adhesion coefficient. People here, when the total brake. Before and after the front of the leaf spring two stress is hs steel shell charge total degree b plate spring yellow width. 2 When the maximum traction condition, the rear leaf spring unilateral transmission at this time, and the horizontal reaction force and 2 are in the opposite direction. Similarly, it can be found that the stress of the front and rear two sections of the rear leaf spring is M2 maximum traction bow is the working condition, and the new distribution coefficient along the shaft. 1.22 When the excavator passes an uneven road under vertical load, the longitudinal force and the lateral force are assumed to be zero. The maximum value of the vertical load applied to the leaf spring is the maximum stress level. When the stress in the middle of the front axle plate is calculated as the rear steel plate, = .2, the stress in the middle of the rear axle plate is 1.23. The vertical load on the side spring is increased when the side skid is slipping during the sharp rotation, and the analysis method is the same when the force is applied to the maximum load. Its force is the distance between the phantom of the inch machine and the plane of the support, and the coefficient of adhesion of the side. From the above formula, the stress in the middle of the left magazine is: N 1+, then the stress in the middle of the left front leaf spring is 1+. The stress in the middle of the left rear leaf spring is as follows: The stress at the two ends of the leaf spring at the point 3 is the most human. According to the two test prototypes, the broken parts of the leaf spring were rolled at two points. 1 is a prototype is left and right front leaf spring break. Explain that this is due to the fact that the emergency braking and the full-scale impact of frequent swift driving have caused the coil 1 to break under the maximum load. The 2nd prototype is a fracture at the left rear leaf spring coil 1. It shows that the towel is often in the most traction and the left sharp driving state under the combined effect of the most human stress resulting in fracture of the steel plate. P Suspension load; If the machine has good smoothness, the frequency of vibration from the mountain should not change with the load. Set corpse, static load, static burn, stiffness, for loading èœ, 1 for the corresponding deflection, stiffness can be known by the 9 frequency, the same, the deflection does not change, that is to say, get ijP children. , 0 = corpse, obtained, the factory, substituted into the corpse plant slewing deflection coefficient is 2 leaf spring tab avoidance and oil and gas suspension characteristics analysis and comparison of new generation of car excavators driving speed is a very important indicator of juice, energy The key to meeting the design requirements is whether it can better solve the suspension problem. For the excavating machinery, when the running speed is less than 35 to 1, the rear axle does not use a suspension device, but only two suspension cylinders are arranged on the front axle. By suspending the distribution valve, the suspension cylinder operates while traveling. Ensure that the wheels are along the ground and improve the smoothness of the ride. When the excavation is performed, the suspension ram is locked. Use leg support to keep the entire machine rigid, such as the 460 model. The suspension device used on the excavator is in the form of a leaf spring suspension torsion bar spring suspended oil and gas suspension. The high-speed excavator dichang rice is suspended by helium gas or leaf springs, and the characteristics of the hydrocarbon suspension form are closest to the ideal state. 2.1 Leaf spring suspension elasticity and ideal elasticity characteristic analysis of ideal elasticity In order to simplify the calculation, the leaf spring suspension mass is regarded as a single degree of freedom vibration mass, and its vibration frequency is therefore. The ideal elastic curve is an exponential function curve. 3 curve 2. 1. Leaf spring elasticity line 1 Ideal elasticity curve 3. Hydropneumatic suspension elasticity curve 32 Characteristics analysis of leaf springs For leaf springs, the stiffness of a leaf spring in a leaf spring is a constant, so its elastic characteristic is a straight line, and 3 is a straight line. . 2.2 Analysis of the elastic characteristics of oil-air suspension The principle of the oil-air suspension device 4 is small, which is mainly composed of the piston damping hole and the air chamber in the lower chamber. Living cold moves the compressed air chamber gas. Suspension produces elasticity, its rigidity is non-linear, and it has been with external pods; 1. Divide the width 2. The cavity 3. The floating piston 4. Obstruction ceremony 5. Membrane 6. The gas chamber is set to load 2 gas volume, the corresponding pressure is when the load is 0, the gas volume is the pressure, the inflation height is From. According to the laws of thermodynamics, the piston is broken and the piston is broken. The height of the piston is high. The working speed of the piston is considered as the adiabatic process. 1.3. The elasticity of the oil suspension is therefore an exponential curve. For example, the curve 3 in the chamber 3 is comparable to the 012 equation. . This curve is close to the ideal elasticity curve. The frequency of the helium suspension vibration can be given by formula 13. The height of inflator and the frequency of vibrations are saved. The smaller the inflation height. The higher the vibration frequency. This characteristic is exactly the opposite of the elasticity of the leaf spring, and it would like elasticity. The frequency of the vibration due to the road is much lower than the hydraulic natural frequency of the oil and gas suspension and thirteen damped orifices are throttled and the damping effect is large. Therefore, 1 has a good shock absorber damping effect. This advantage is not the nature of the leaf spring. 3 Conclusion The use of leaf springs to directly load heavy steamers on a high-speed auto excavator is a new attempt. There is no precedent for the front excavator line 1. Lack of design experience and information, the emergence of leaf spring break in the prototype test should be reasonable. It is not advisable to use the leaf springs of the load-carrying trucks as excavator suspensions. It should be redesigned according to the operating conditions of excavators. Otherwise it will cause the steel plate to break. The selection of the structural form of the car-type excavator suspension device is preferably based on a helium vapor suspension device. It can better absorb the impact and vibration in high-speed mechanical driving, and better adapt to the excavator's requirements for elasticity and rigidity change under running and working conditions. Reference i sacrificed. Research on Hydro-pneumatic Suspension Characteristics of Construction Machinery. Engineers and equipment research, I9S8 2 Xiangguang and other engineering machinery chassis. 1982 edition 3 Chief editor Chen Jiarui. Automotive structure. Jilin University of Technology, 1997 4 Han Jun and so on. The Development Prospect of Auto Excavators in China. Construction Machinery, 1999 Yang Chengxian. Engineering Forces Military Representative Office in Guiyang District No. 97, Zhongcao Road, Guiyang City, Guizhou Province, China Received 3000714 The editor Yang Xiaoguang has received a 58-page repair and reinforcement plan. He must consult the relevant authorities to find out the reasons and reduce losses. Loader operating conditions are complex. The frame is loaded during the work. During your design, you should pay special attention to the stress changes in the local sharp area and the local thickness variation area. To avoid strong stress concentration, you should increase the bending radius of the plate, increase the radius of the chamfer, and use the slope. The twisted welding test offers 1 Guangyu. Construction machinery chassis structure and design. Beijing China Building Industry Press. 1986 Gu Limu 1. Xi'an, University of Science and Technology. 7055 Xi You Zhang Youyun, Xi'an Jiaotong University 710049, Xi'an, China 33,056 Received
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