The secondary spring system of the original electric locomotive consists of 4 sets of common cylindrical compression springs. The parameters are: spring material diameter d=48mm, maximum working ring diameter D=230mm, effective working circle number n=6.6, free height H0=528mm The working height is H=431mm. The characteristic curve of the spring is approximated as a straight line, the rigidity is stable, and the structure is simple. However, the stiffness of the spring is now mainly in the direction of the axis, and its transverse shear and bending stiffness are poor, and its anti-resonance ability is poor. After the train speeds up, its snake-like movements and swaying cars intensify. Therefore, it is necessary to improve the spring system of the electric locomotive.
Improvement of the spring system The modified spring parameters and characteristics take into account the special position of the secondary spring (between the bogie and the body) and the specific role (supporting the body and damping), under the premise of ensuring high freedom and so on. The cylindrical helical compression spring was modified to a constant-pitch conical compression spring. The distance t can be calculated by the formula: H0=6.6t+1.5dT=(528mm-1.548mm)/6.6=69.09mm The maximum working radius R2=115mm, the minimum working radius R1=101.8mm, and the pressing time distance d=d1-R2 -R1nd2=47.96mm The improved conical compression spring has an increased rigidity, the characteristic curve is a gradual increase, and the anti-resonance ability is enhanced.
The effect of the spring end moment on any section A indicates the effect of the unit transverse force on any section A. The improved spring bending stiffness and the transverse stiffness bending stiffness The distance from any section A of the conical spring to the force end of the spring is , = R1 In the +R2-R12ntan formula, the polar angle of the helix; the helix angle.
The effect of spring end bending moment on any section A is shown. The bending moment M at the force end of the spring is the torque produced by the cross-section A and the bending moments in the two directions are Tt=McoscosMb=-McossinMn=Msinds=R1+R2-R12ncosd where Tt is the torque applied to the cross-section of the spring material; Mb, Mn is the bending moment of the spring material section; ds is the length of the tiny section of the spring material.
The effect of unit lateral force on any section A is shown. When Pr=1, the torque and bending moment generated by unit force in section A, respectively, Ip is the polar moment of inertia; Ib, In is the moment of inertia; E is the elastic modulus of the material; Poisson's ratio. Reference values ​​R1=101.8mm, R2=115mm, n=6.6, d=48mm, E=2G(1+)(=0.25, G=80109Pa), Ip=2Ib=2In=d4/32 substitution, after integration Fr = (544011.7 / (EIn)) MM = (EIn/544011.7) Fr = 95798N so the bending stiffness is 95798N.
The bending stiffness of the original cylindrical spring can be calculated according to the formula (7-42) in the literature. M=Ed416D2nH(2+)Fr=42604.5N Therefore, the bending stiffness of the original cylindrical spring is 42604.5N, and the bending stiffness of the bright circular spring is improved. Transverse stiffness As shown, the torque and bending moment of section A caused by the lateral force Pr are (since small, desirable sin=0,cos=1) Tt=PrR1+R2-R12ntancos3
According to the formula (7-51) of the literature, the lateral stiffness of the original cylindrical spring obviously means that the transverse stiffness of the conical spring is higher than that of the cylindrical spring.
Conclusion At present, the spring system of most locomotives in foreign countries is still a cylindrical spring, but its railway quality is generally higher than that of China (such as the orbital ripple index in foreign countries is 0.20.4, and railways in China have not yet had a ripple index). The cost of similar transformations in China's railway system will be very high. Therefore, in China, the key to improving the smoothness and safety of vehicle operations is to improve the locomotive's spring system. Through the theoretical derivation and quantitative calculation of the new design scheme in the paper, it is proved that the lateral stiffness and bending stiffness of the improved spring system are significantly increased, thereby realizing the active control of the resonance of the locomotive during high-speed operation, and greatly improving the high-speed operation of the locomotive. Safety and smoothness. This design scheme has been used by Zhuzhou Electric Locomotive Works for the construction of the new type of train, the Lushan SS9.
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