In the previous articles, we introduced the three major processes used in the bridge factory to guarantee the strength and toughness of the trailer bridge, which played a key role in the performance of the subsequent use of the vehicle bridge. However, the quality of an axle is not up to standard, but not only depends on strength and toughness, production accuracy is also extremely key.
Although the appearance of the trailer bridge looks relatively simple and heavy, it seems to be not with the word "precision", in fact, it is worthy of the name of precision machinery, a trailer bridge components up to 100 parts. Because of this, it is crucial for Semi Trailer Manufacturers to control the machining accuracy of trailer bridge.
Next, let us take a look at which processes are used to ensure the accuracy of the finished product.
1, axle alignment
The straightening process is typically set after the heat quenching and tempering treatment and sandblasting rust removal, which is used to correct various bending caused by the axle in the production and processing process.
Although after the front of the hot rolling, hot tempering, sandblasting and other processes, the axle strength and toughness has been a certain degree of excitation, but in the process of processing, especially in the process of heat tempering treatment, still can not totally avoid the axle appearing subtle, the naked eye can not identify the bending phenomenon.
If the deformation is not restored through the straightening process, the stress distribution of the shaft beam or shaft end parts in use will be directly affected. If it is light, the body will be shaken and the driving will be unstable, and if it is heavy, the axle will crack or directly break the axle, which will affect the driving safety.
Axle adopts automatic multi-point straightening machine, the accuracy can reach 0.4-0.5mm, can automatically correct the axle in the process of processing or heat treatment of various bending phenomena, for the finished product processing accuracy to provide a basis.
2, numerical control machine tool processing
CNC machine tool processing is set after the primer process, before the intermediate frequency strengthening treatment, mainly on the shaft body boring, milling, drilling, precision grinding and so on.
Numerical control machine tool processing mainly for shaft head, to the subsequent installation of wheel, bearing, brake drum shaft head and additional components to provide the basis of installation, is equal to the existence of high-rise building foundation, the higher machining precision, the groundwork for the subsequent assembly precision, avoid unnecessary friction wheel side parts appear loss, enhance the operation reliability of the wheel end system, The longer the maintenance cycle.
Compared with the ordinary machine tool, CNC machine tool processing parameters can be written in the form of application in the numerical control device, such as the relative motion between the tool axis head track size, grinding process parameters and various auxiliary operation information, etc., and then by the nc device through analysis processing, signal, and corresponding procedures and instructions for automatic processing.
In this way, not only is the processing efficiency higher, more critical is the processing stability is stronger, because the operation of CNC machine tools is out of constant calculation, output, feedback control, can ensure the accuracy of the relative position of the tool and shaft head, avoid human error, processing quality is more stable.
3. Automatic welding
In the production process of axle, welding work is considerably less than that of trailer production, which is mainly used in the welding of brake floor, spherical bearings, air chamber seats and additional parts. After the welding is completed, the axle welding semi-finished product can be obtained, which is also one of the main products of Dayong axle.
The welding process of the vehicle and axle adopts the robot automatic welding, and the laser location finding system is used to track and identify the position of the weld, to ensure the consistency, beauty and robustness of the weld, and the welding quality is more stable.
4. Finished product assembly
Assembly requires the installation of wheel hub, brake drum/brake disc, internal and external bearings and additional components on the basis of welding semi-finished products to get the finished axle. After the end of the production process, into the finished product quality inspection link.
Assembly accuracy mainly includes dimensional accuracy, relative motion accuracy, mutual position accuracy, contact accuracy, etc., among which dimensional accuracy also includes coordination accuracy and distance accuracy. The precision control of assembly process is mainly divided into two points: the precision of parts themselves and the precision of assembly technology.
In order to better guarantee the precision of parts, the axle chooses the purchased accessories, such as bearings, wheels, brake drums, etc., all choose domestic strength brands, ranking among the best in their respective fields. On the one hand, these brands have been working in the parts industry for many years, and their quality has been baptized and tested by the market, so they have the corresponding quality assurance ability. On the other hand, after the arrival of accessories, but also a series of tests on its strength, accuracy, etc., qualified rear can be put into use, to add a layer of quality protection.
In terms of assembly technical accuracy, automatic assembly line is selected for the axle, with high-precision guidance, positioning, feeding, adjustment, detection, and additional instruments. In the extremely repetitive assembly task, the high accuracy and consistency of assembly process are guaranteed, and the unqualified rate is completely reduced or reduced.
In fact, in addition to the aforementioned rotary rolling, hot conditioning, intermediate frequency reinforcement and axle alignment in this issue, numerical control machine, automatic welding, finished product assembly, axle production process is also equipped with material cutting, shaft head preliminary processing, cold side, sand blasting, priming paint spraying, paint spraying, shaft head precision inspection process, supplement each other, mutual cooperation between them, Jointly cast the quality cornerstone of the finished axle.