Spring Clip Structural Design and Clamping Force Characteristics
- What are the common structural types of elastic clips? What are their characteristics?
Common types include Type Ⅰ elastic clips, which have a relatively simple structure, are arc - shaped with elastic arms at both ends, and have moderate clamping force, suitable for ordinary lines. Type Ⅱ elastic clips have an optimized structure on the basis of Type Ⅰ, with longer elastic arms, better elasticity, larger and more stable clamping force, and are often used in heavy - haul railways. Type Ⅲ elastic clips are bolt - free, fixed by components such as gauge baffles, with a compact structure and uniform clamping force distribution, suitable for high - speed passenger dedicated lines, and can reduce the impact of train vibration.
- How do the structural parameters of elastic clips affect their clamping force?
The cross - sectional size of the elastic clip has a great impact. The larger the cross - section, the stronger the rigidity, and the greater the clamping force can be generated under the same deformation, but an excessively large cross - section will reduce elasticity. The length of the elastic arm is also crucial. When the length is moderate, the elastic clip deforms reasonably and the clamping force is stable; if it is too long, the rigidity is insufficient and the clamping force is too small; if it is too short, the elasticity is poor and excessive stress is easy to occur. In addition, the bending angle of the elastic clip determines its initial deformation, and an inappropriate angle will lead to insufficient or excessive clamping force.
- What are the different requirements for the clamping force of elastic clips in different lines?
Ordinary lines have relatively low requirements for the clamping force of elastic clips, generally 8 - 10kN, which can meet the needs of daily train operation. Due to the large axle load of trains in heavy - haul railways, the clamping force of elastic clips is required to be larger, usually 12 - 15kN, to prevent the rail from displacement under large loads. High - speed railways have extremely high requirements for the stability of clamping force. The clamping force must be maintained at 10 - 12kN with a small fluctuation range, to avoid affecting the track smoothness due to changes in clamping force.
- How to test the clamping force of elastic clips?
A clamping force detector can be used. It is installed at the contact part between the elastic clip and the rail, and the pressure value exerted by the elastic clip is measured by a sensor to directly read the clamping force data. The detection must be carried out after the elastic clip is installed in place and the bolt is tightened, and no less than 5 elastic clips are sampled and detected per 100 meters of track. The clamping force can also be calculated by measuring the deformation of the elastic clip and combining with parameters such as its elastic modulus. This method requires ensuring the accuracy of measuring deformation.
- What changes will occur to the clamping force of elastic clips during use? What are the reasons?
In the initial stage of using the elastic clip, the clamping force may decrease slightly, which is because the elastic clip has a certain stress relaxation phenomenon, and the material produces micro plastic deformation under long - term stress. With the increase of service time, if the elastic clip is worn, rusted or deformed, the clamping force will further decrease, even lower than the standard requirements. In addition, loose bolts and aging under - rail pads will also lead to a decrease in the clamping force of the elastic clip, affecting the fastening effect on the rail.