The brake disc is the friction couple of the disc brake, and the brake drum is the friction couple of the drum brake. In addition to various retarding devices, automobile brakes are almost all friction brakes that use the friction between the fixed element and the working surface of the rotating element to generate braking torque.
The brake disc is a rotating element in the friction pair of the disc brake, and its shape is a metal disc working on both ends; the basic shape of the brake drum is a drum shape, and there are connecting holes on the installation surface.
When working, the brake disc is not only subjected to a large normal force and tangential force exerted by the brake pad, but also bears a much larger thermal load than the brake drum. warping, resulting in friction noise and scratches. In order to make the brake disc have proper heat capacity and good heat dissipation performance, full consideration must be given to its structure and thickness. The structure of the brake disc is divided into two types: solid type and ventilated type, the latter can reduce the temperature rise by 20% to 30%. Audi, Cherokee, Santana 2000, Fukang (AL, AG) cars and many other cars use ventilated brake discs with a thickness of 20~22.5mm; other imported cars use solid brake discs with a thickness of 10~13mm. The material of the brake disc is gray cast iron, or alloy cast iron with Cr, Ni, etc. added. During manufacture, the runout of the end face of the brake disc, the parallelism (thickness difference) and the unbalance of the two end faces should be strictly controlled. In use, the limit end face runout of the brake disc should not exceed 0.06~0.15mm. This means that the machining standards of the brake discs are very strict and the machining accuracy is also very high.
Similarly, if the brake drum is improperly designed, it will be volatile when heated; if the force of the brake drum is unbalanced, it will also produce mechanical deformation, which will cause poor contact between the shoe and the drum, resulting in increased pedal force and stroke; When the roundness is too large, it will also cause self-locking and generate vibration and noise. Therefore, the brake drum should have sufficient wall thickness, and cast circumferential or axial reinforcing ribs on the outer surface near the opening to improve strength. These ribs also play the role of heat dissipation, which can reduce the temperature of the friction surface, shorten the cooling time of the brake, and increase the energy capacity by 35% to 40%. The working surface of the brake drum is generally finished with the bearing hole positioning after being assembled with the wheel hub. Mini-cars require working surface roundness and coaxiality tolerances ≤ 0.03mm, radial runout ≤ 0.05mm, and static unbalance ≤ 1.5N·cm. The high processing requirements of brake discs and drums determine that they need professional machine tools equipment for processing.
CNC lathe is one of the most widely used CNC machine tools. It is mainly used for cutting inner and outer cylindrical surfaces of shaft parts or disc parts, inner and outer conical surfaces of arbitrary taper angles, complex rotating inner and outer surfaces, and cylindrical and conical threads, etc., and can perform grooving, drilling, reaming, reaming Holes and borings, etc.
The CNC machine tool automatically processes the parts to be processed according to the pre-programmed processing program. We write the machining process route, process parameters, tool motion trajectory, displacement, cutting parameters and auxiliary functions of the part into a machining program list according to the instruction code and program format specified by the CNC machine tool, and then record the content of the program list. On the control medium, it is then input into the numerical control device of the numerical control machine tool, thereby directing the machine tool to process the parts.
Advantages of machining brake disc drums with CNC lathes:
1. High processing precision and stable processing quality, which can ensure the quality and precision of the finished brake disc brake drum.
2. It can carry out multi-coordinate linkage, and can process brake disc brake drums with different shapes and appearances;
3. When processing the brake disc brake drum, it is generally only necessary to change the numerical control program, which greatly saves the production preparation time
4. The machine tool itself has high precision and high rigidity, which can process the brake disc brake drum well and ensure the precision of the brake disc brake drum.
5. The favorable processing amount can be selected, and the productivity is high, which is generally 3~5 times that of ordinary machine tools.
6. The machine tool has a high degree of automation, which can greatly reduce the labor intensity of workers and ensure product quality and accuracy;
As a leading manufacturer of industrial lathe machinery and machine tools in China, Shanghai Antis has 20 years of experience in machine tool production. The lathe machinery and other equipment produced are not only used in the automotive industry, construction industry, but also in the mold industry, automotive The most commonly used brake disc brake drum is a double-knife CNC vertical lathe, which can realize machining, drilling and grinding with high precision.
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