以粉末冶金法制备铜基粉末冶金摩擦材料,采用洛氏硬度计和夏比冲击试验机对摩擦材料的力学性能进行表征,利用MM-3000型摩擦磨损性能试验台研究了刹车速度对材料摩擦磨损性能的影响,并借助电子扫描显微镜(scanning electron microscope,S...以粉末冶金法制备铜基粉末冶金摩擦材料,采用洛氏硬度计和夏比冲击试验机对摩擦材料的力学性能进行表征,利用MM-3000型摩擦磨损性能试验台研究了刹车速度对材料摩擦磨损性能的影响,并借助电子扫描显微镜(scanning electron microscope,SEM)观察了摩擦材料的微观形貌。研究表明:铜基粉末冶金摩擦材料的摩擦磨损性能与刹车速度密切相关,随着刹车速度的增大,摩擦吸收功率近似线性增长,而摩擦系数呈先增大后减小的趋势;在高速刹车条件下,铜基体自身发生软化会破坏摩擦材料表面形成的氧化膜,降低了分子键的抗剪切强度,从而增大了磨损量。展开更多
Compared to the current eddy braking patterns using a single magnetic source,hybrid excitation rail eddy brakes have many advantages,such as controllability,energy saving,and various operating models.Considering the l...Compared to the current eddy braking patterns using a single magnetic source,hybrid excitation rail eddy brakes have many advantages,such as controllability,energy saving,and various operating models.Considering the large braking power consumption of the high-speed train,a hybrid excitation rail eddy brake system,which is based on the principle of electromagnetic field,is proposed to fulfill the needs of safety and reliability.Then the working processes of the mechanical lifting system and electromagnetic system are demonstrated.With the electromagnetic system analyzed using the finite element method,the factors such as speed,air gap,and exciting current have influences on the braking force and attractive force.At last,the structure optimization of the brake system is discussed.展开更多
文摘以粉末冶金法制备铜基粉末冶金摩擦材料,采用洛氏硬度计和夏比冲击试验机对摩擦材料的力学性能进行表征,利用MM-3000型摩擦磨损性能试验台研究了刹车速度对材料摩擦磨损性能的影响,并借助电子扫描显微镜(scanning electron microscope,SEM)观察了摩擦材料的微观形貌。研究表明:铜基粉末冶金摩擦材料的摩擦磨损性能与刹车速度密切相关,随着刹车速度的增大,摩擦吸收功率近似线性增长,而摩擦系数呈先增大后减小的趋势;在高速刹车条件下,铜基体自身发生软化会破坏摩擦材料表面形成的氧化膜,降低了分子键的抗剪切强度,从而增大了磨损量。
基金Project supported by the National Natural Science Foundation of China(Nos.50877070 and 51105331)the Special Financial Grant from the China Postdoctoral Science Foundation(Nos.201104720 and 201104721)
文摘Compared to the current eddy braking patterns using a single magnetic source,hybrid excitation rail eddy brakes have many advantages,such as controllability,energy saving,and various operating models.Considering the large braking power consumption of the high-speed train,a hybrid excitation rail eddy brake system,which is based on the principle of electromagnetic field,is proposed to fulfill the needs of safety and reliability.Then the working processes of the mechanical lifting system and electromagnetic system are demonstrated.With the electromagnetic system analyzed using the finite element method,the factors such as speed,air gap,and exciting current have influences on the braking force and attractive force.At last,the structure optimization of the brake system is discussed.
