Camshafts are usually machined. It can be divided into rough machining of cam surface and finishing of cam surface. Divide the processing stages in the processing process and analyze the processing process. If there is a quality problem in camshaft machining, it should be solved in time.
Rough machining: the outer circle of each support journal, timing gear journal and thread journal, automobile cam, eccentric wheel, etc.
Medium finish: coarsely ground cams, eccentric wheels, etc.
Finishing: precision grinding of timing pin journals and thrust surfaces, 4 outer circles of bearing journals, precision grinding of cams, and eccentric wheels.
Finishing: precise support journals, cams, eccentric wheels.
Rough surface of cam
Positioning: Use the end face of the bearing journal as the axial positioning. Use the outer circle of the timing gear and the support shaft as a positioning reference. Roller-type auxiliary supports are used for processing.
Surface finish of cam
Double cam grinder: This machine has two sets of main machines, which are automatically replaced by the main machine. Controlling the diameter of the grinding wheel can improve the accuracy of the cam profile.
Double-circulation cam grinder: The entire cam of the camshaft can be continuously rough-grinded once installed. First, all cams are rough-ground at a high feed rate of 60m/s, and all cams are ground at a grinding rate of 30m/s, and then fixed after finishing.
Analysis of camshaft processing technology
- (1) Cubic boron nitride grindstone is used to increase the life, reduce the wear of the grindstone, and improve the accuracy.
- (2) Numerical control cam grinder: The computer is used for numerical control programming to eliminate the influence of cam accuracy on cam accuracy.
- (3) The electro-hydraulic pulse motor is used to control the synchronization of the headstock and the grindstone frame.
- (4) High-speed grinding using multiple grinding stones and high-strength grinding stones.
- (5) Use the grindstone shaft swing device to reduce the surface roughness of the cam surface.
- (6) Use preselection devices such as preselection rough milling and milling tolerance.
- (7) Use active measuring device.
- (8) Use automatic correction, automatic trimming and other devices.
Quality problems and solutions that may occur in camshaft processing
After the shaft is repaired, the grinding wheel is not round
Possible problem: When processing on a single-board machine, the program will be mixed, the processing size is unstable, and the tempo is very poor.
Solution: Replace the turning support journal equipment, replace the control system, and check the single-board computer regularly.
Cam lift tolerance
Possible problem: The machine tool wears on the Mold, reducing the accuracy of the mold.
Solution: Check and repair regularly, and replace the master in time. When grinding the cam surface, the method of changing the rotation direction of the workpiece is adopted to improve the shape accuracy of the cam curve.
Cam-based bounce tolerance
Possible problem: The machine tool wears on the mold, reducing the accuracy of the mold.
Solution: Regularly check, repair, and even replace the main shaft and coupling guide shaft.