Precautions for daily maintenance and calibration of semi-trailer
The five key considerations during semi-trailer calibration are that a good chassis condition is the foundation of positioning, and semi-trailer positioning mainly calibrates the condition of various components of the semi-trailer. And the real measurement is just adjusting the balance of the bridge. With a good chassis condition, how can we adjust the balance of the bridge more quickly? What issues do semi-trailer manufacturers pay attention to during the calibration process?
A flat and smooth surface is a prerequisite for tuning semi-trailer trucks
A flat and smooth work site can improve the accuracy and speed of calibration. The impact of the site mainly comes from the deviation between the left and right sides. When the deviation between the left and right sides is greater than 2CM, it will cause a deviation of 1cm in the measurement data. When working on uneven road surfaces, it is normal for measurement deviations to occur due to uneven wheel positions. Therefore, during mobile operations, there may be certain measurement deviations caused by the influence of the ground.
Good prediction and communication with customers lay a solid foundation
Prediction is also very important when tuning a semi-trailer. It mainly refers to predicting the distance of inter axle deviation, which can be achieved by observing the balance of the tires on both sides, the left and right deviation of the steel plate in the lifting ear, and the left and right position deviation between the tires and the lifting ear to predict and verify the positional relationship between the semi-trailer axles. It can determine the distance deviation of the vehicle wheelbase of 5mm or more, and predict the direction of the vehicle's tail swing. This lays a solid foundation for adjusting assignments and communicating with clients.
Three things to pay attention to when adjusting the pull arm of a semi-trailer
1. When adjusting the pull arm, since the main function of the pull arm is tension, in order to ensure the changing trend of its fixed rod, we should extend it before shortening it to the standard state during adjustment. When adjusting the pull arm, attention should also be paid to the changes in the gap between its left and right sides to ensure that the pull arm is in a pulled state.
2. When adjusting the wheelbase with a large deviation, the change in the pull arm after one turn is about 4mm, the change in the wheel edge distance is about 1cm, and the adjustment ratio is about 1:4. When one side of the active pull arm is extended or shortened by 4mm, the fixed pull arm side will be shortened or extended by 1mm, in a 4:1 ratio.
3. When adjusting wheelbase with significant deviation, we should always observe the position of the steel plate to avoid it getting stuck to one side and affecting the calibration effect. When adjusting the tension arm, we should pay special attention to the fact that it becomes increasingly difficult to adjust the steel plate by using a large hammer to strike it. This will result in a higher repair rate for the adjusted car.
Three reasons for semi-trailer tail shaking and their corresponding solutions
There are several reasons for semi-trailer tail shaking, including the main vehicle running diagonally (mainly due to misaligned driving wheels, resulting in thrust angles), misaligned traction pins (deviation of more than 5mm), and overall three-axis offset (positioning reasons). We can determine this through measurement or road testing.
In general, if the drive axle is not aligned, the semi-trailer will swing towards the front of the drive axle. An improper traction pin will cause the tail to swing in the direction of the traction pin deviation. The three axes are not aligned as a whole, and the tail is thrown towards the back. We can solve it by targeting its faults. We can also adjust the overall deviation of the three semi-trailer axles slightly.
