Design of Welded Shell of Container Semi-trailer Axle Square Tube Xiangfan Dongfeng Heavy-duty Axle Co., Ltd. Hou Guozhang Descriptor: Axle Shell Design and Calculation The more important, the semi-trailer axle as an important part of the semi-trailer, plays an important role in carrying and braking. Therefore, the appropriate strength and good braking performance are the corrected workpiece tolerances in Table 2 where the measurement capability index Cg exceeds the confidence interval. The third item in Table 2 is "corrected workpiece tolerances" (sometimes called "process tolerances") The meaning of the expression is: when the measurement capability index Cg value of the inspection tool is less than 2.0, if they are required to achieve the measurement accuracy of the corresponding inspection tool with G = 2.0 in actual use, the method of correcting the tolerance T of the workpiece to be measured can be adopted. That is, according to the specific situation of the Cg value, appropriate compression is applied, that is, when the same workpiece is detected, the range between the limit errors at both ends is tightened.
For example, the tolerance of the tested part is 0.08mn, that is, Ll is determined by a certain test tool, and its Cg = 1.33. In order to have a measurement accuracy equivalent to CgL, the tolerance T needs to be compressed according to Table 2, the amount is 4m. Indicate the necessary conditions for using this inspection tool semi-trailer axle in the future.
The function of the semi-trailer axle determines the structure it must have. It is mainly composed of a round tube or square tube welded shell and axle tube, brake assembly and hub brake drum assembly. The round tube shell is relatively simple, only the design of the square tube welded shell is discussed here. The trailer axles with this structural feature have been mass-produced in foreign countries. When the BPW in Germany actually measures this kind of workpiece, it can be completely trusted only when the measured value is between L0 =. When the measured value is located at the two ends of the tolerance of 2m, these workpieces need to be taken out and isolated, and then they are measured again with a higher-precision testing instrument. Because although the measurement results of this part of the workpiece are not very reliable, they are not necessarily out of tolerance.
This method can be extended to a more general situation, because in most cases, the measurement capability index required by in-use inspection tools and measuring instruments on the production line does not require Cg> 2.0, and often Cg> 1.33 is sufficient. At this time, the corresponding data in Table 2 must be adjusted, and the confidence level at Cg = 1.33 is considered to be an ideal state. Its corresponding "process tolerance" should be taken as 100%, and the items on the right should be changed accordingly. For example, when Cg = 1.0, the corrected process tolerance as the control measurement result is 95% T instead of 90% T relative to Cg 0. The specific implementation is similar to the situation described previously. If the measured part tolerance T =). 08nnn, both ends need to compress 4pim company and American DANA company. At present, there is no domestic manufacturer specializing in mass production of such axles. The container semi-trailer axles currently used in China are mainly imported. With the development of the domestic transportation market, the demand for container semi-trailers will continue to increase. Through market research, according to the requirements of Dongfeng Motor Company, Yangzhou Tonghua Semi-trailer Factory and Guangdong Shunde Trailer Factory, and combining our company's advantages in manufacturing heavy-duty stamping and welding axles for many years, we designed and manufactured 11t-class semi-trailer axles.
2 Axle shell design and calculation 2.1 Outer shape design Welded half-shells stamped from two steel plates into a shell, and then welded hub axle tubes at both ends, thus forming the axle shell, see the structure of the shell It is a round tube at both ends of the middle square tube. After boring at both ends, it is connected to the hub axle tube through a bushing ring. According to foreign general standards and manufacturers' requirements, two sets of square tube section rulers 14 (mm) are designed (the strength calculation is based on the latter square tube section calculation). The outer diameter of the round tubes at both ends of the shell is 170. The hub axle tube directly uses the Dongfeng EQ1141G rear axle hub axle tube produced by Nissan Diesel Technology. The hub axle tube is welded to the housing after finishing, this method can simplify the processing technology of the axle housing.
Divide the cross-section of the axle housing into I, for three typical figures, see. Calculate the algebraic sum of the moment of inertia of each figure to the horizontal axis x axis of the centroid, which is the moment of inertia of the entire cross section of the axle housing. Then calculate the WI block figures to be two rectangles of equal size and symmetrical to the x axis.
1 / ring for d. Combine the four 1/4 rings into two half rings, first calculate the inertia moment x of the half circle itself, and then transfer the inertia moment of x to the x axis I The distance Y from the centroid of the half circle to its center Y.:I The skin pattern is two rectangles of equal size and the same horizontal axis as the x axis.
Moment of inertia of the entire square tube section: Substitute each data to obtain = 2082. Flexural section modulus: 2.2.2 Strength calculation For semi-hanging bridge shells, general stress analysis calculations can be divided into four states: bending torsion during rolling resistance Synthetic stress, bending-torsion synthetic stress during emergency braking, bending stress when there is maximum vertical dynamic load through different road surfaces, and bending stress and shear stress at the inner bearing of the outer wheel when subjected to maximum lateral force (this stress is On the hub axle tube, and the hub axle tube is borrowed from the hub axle tube of the rear axle of the EQ1141G, the calculation is omitted) the full load of the semi-trailer is 11U a. The bending moment force of the axle housing is the vertical load caused by the weight G2, the horizontal bending moment MB 'caused by the rolling resistance Ff, and the torque Mr. caused by the rolling resistance. The maximum stress S at this time is the maximum vertical dynamic load on the steel plate (10) c The bending stress when passing through uneven road surface, the bending stress when the axle housing is subjected to the maximum vertical dynamic load, the tire plus the rim weight, the distance between the two leaf spring seats of about 980N S is 1.030m Mb 'The horizontal bending moment Mb caused by rolling resistance The maximum rolling resistance of the Ff wheels substitutes the above coefficient into the torsional section coefficient of Wn, 5.05X104m3 (the calculation process in front) /S=3.56, which meets the needs.
It is: dynamic load factor, 2 substitution, get = 1.58X108Pa safety factor n = / = 3.22, meet the needs.
Axle shells designed and manufactured according to the above design are loaded one million times without permanent deformation or breakage when tested in accordance with relevant national standards. This shows that the design is successful.
3 Brake and hub brake drum design and selection For semi-trailer axles, good braking performance is very important. After an extensive investigation and research on the domestic heavy-duty vehicle brakes, after comparison, we found that the Dongfeng EQ1141G automobile rear brakes have better braking performance. Therefore, we selected the main components of the EQ1141G rear axle brake assembly and the hub brake drum assembly. At the same time, considering the fact that the semi-trailer has a long brake air path and low air pressure, high-performance friction linings were selected during the design, with a friction coefficient of 0.45 (EQ1141G friction lining friction coefficient of 0.4) and lengthened adjustments. arm.
4 Conclusion The semi-trailer axle with square tube welded shell structure overcomes the shortcomings of large overall processing equipment for the axle shell and difficult to guarantee accuracy, simplifies the processing technology, improves the strength of the axle shell, and has a certain overload capacity, easy to achieve Mass production, safe and reliable braking performance ensure the safety of use. Its shortcoming is that it is easy to be damaged at the welding seam between the axle housing and the hub axle tube during use, which can ensure its compliance with the design requirements by controlling the welding quality. Therefore, this type of semi-trailer axle can meet user requirements.
Suzhou Yuli Industrial Co.,Ltd , https://www.packageyuli.com