Longitudinal impact force of train is too large in operation (1) With the increase of train speed, the increase in tonnage of towing and the increase in the number of closed doors due to brake failures in trains, when the train is in operation when starting, decelerating, and braking , It will have a greater longitudinal impact on the vehicle. (2) The stroke of the brake cylinder piston does not meet the requirements. During the overhaul, careless attention was paid to the adjustment of the A bar (A push) value of the brake regulator, resulting in inconsistent braking wave speeds during train operation, resulting in longitudinal impact of the train. (3) When the train encounters an emergency in normal operation and the emergency brake is applied to stop, it will cause instantaneous longitudinal impulse of the train, especially when the train is running at high speed, the emergency braking is more serious. (4) During the shunting operation of the vehicle, the shunting vehicle slipped, causing heavy hooking due to impact or improper control of the shunting speed.
Problems of the buffer itself (1) The MX-1 rubber buffer has unstable rubber performance, is easily affected by air temperature, and has aging problems. (2) The speed of rubber anti-impact action is relatively fast, and it is easy to cause the separation of the vehicle during shunting operation, and when the impact force exceeds the strength of the rubber, it will cause the rubber to be damaged. Therefore, in the case of greater impact force and higher shunting impact speed, this type of shock absorber is no longer applicable.
(3) The box structure is unreasonable and cracks are likely to occur. The box body adopts a large open structure at the bottom. When the rubber sheet is damaged and needs to be replaced, the maintenance operation is inconvenient. Especially after the small mouth of the box body is worn out, it cannot be repaired, causing the wedge to protrude. When the vehicle is impacted, the wedge severely squeezes the small mouth of the box, causing it to crack.
The current coupler buffer device is the same as the previous coupler buffer device in terms of structure and connection method. The longitudinal gap between the coupler and buffer device is too large. The train impacts longitudinally.
The buffer capacity is small. As far as the requirements of truck buffer performance are concerned, to a large extent depends on the continuous hanging speed of trucks during shunting. China’s 5 Railway Technical Management Regulations 6 stipulate that the allowable speed of wagons at marshalling station shall not exceed 5km/h. If the capacity of the buffer is too small (35kJ), the buffer will be crushed when the speed is lower than the allowable speed. As a result, a rigid impact is generated, and the impact force and impact speed rise sharply, which eventually leads to premature fatigue failure of the vehicle or damage to the loaded cargo.
When the train encounters various impacts, the reasons for the impact force caused by the shearing and breaking of the center plate bolts are as follows: (1) When the train runs through the turnout and the curve section, the lateral swing of the vehicle is increased, which is caused by the small curve radius. The centrifugal force and the super-high side pressure of the outer rail increase. (2) When the vehicle is in the automated hump operation, the speed of the vehicle is too fast, and the inertia generated by the brake shoe braking instantaneously. (3) In the shunting operation, the continuous hanging speed is not well controlled, so that all the buffers are crushed, causing a rigid impact.
The existence of the above-mentioned reasons reflects that the quality consciousness is weak and cannot be repaired according to the standard, which leads to the weakening of the buffer performance. In the high-speed train operation, these problems may not directly affect the driving safety, but once coupled with other bad conditions, it is easy to cause the vehicle to derail or subvert.
Preventive measures and improvement suggestions MX-1 rubber buffer (1) Strengthen the quality awareness of employees, strictly follow the process for maintenance, strengthen the selection of wedges and pressure blocks, control the extension of the wedges, and ensure that the pressure blocks and wedges The quality of assembly. (2) As the MX-1 rubber buffer is no longer suitable for high-speed and heavy-duty requirements, as the construction speed of trucks increases, the research and development of large-capacity new buffers should be accelerated. (3) Train inspection should actively deal with the brake failure in the train to close the car, reduce the longitudinal impact of the train, and improve the operating conditions. (4) The regular inspection must strictly control the A bar and A push value of the brake regulator to ensure that the stroke length of the brake cylinder piston meets the regulations.
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