The Crankshaft Grinder Typically Has A Typical Structure and Advanced Grinding Process

For crankshaft processing equipment, grinder is the final processing machine to make product parts meet the process requirements, solid to its accuracy requirements are very high, extremely difficult complex. For workpiece length swells more than 6m, weight exceeds 5t, the spindle neck and connecting rod neck roughness value of the workpiece to achieve R a s. 0.4 to 0.6 m, spindle neck, rod neck diameter tolerance in 0.008mm, spindle neck and connecting rod neck straight line The degree scored at 0.01 / 200 mm, the serial neck cylindrical degree of 0.015 mm, the technical requirements of the rod neck fraction of the 15' and the processing of large crankshaft grinding at different angles and different eccentricity sandel neck grinding, the requirements are even higher.

According to the current condition of the existing equipment and processing process, the crankshaft in the grinding machine processing is carried out in two steps, that is, the processing grinding spindle neck and rod neck are implemented separately by the two models, which is mainly subject to the limitations and constraints of the equipment structure. General grinding spindle neck selection in a large ordinary outer round grinder, crankshaft rely on the outer round grinder's head frame single drive, in the second top and center frame support gradually grinding the spindle neck. In the process of grinding the spindle neck, the dimensional accuracy and technical requirements of the product are directly interfered with by human. Especially in the central frame in both directions to support the strength of the control, which depends on the proficiency of the operating workers, but long-term reliance on human factors to ensure the quality of stability is difficult to do, but also unscientific. When processing the grinding rod neck diameter, a special crankshaft grinder is selected for machining. This crankshaft grinder's head and tail seat chucks can be based on the center axis of the head and tail seat, according to the crankshaft spindle neck and the link neck stroke eccentricity adjustment, so that the head and tail plate chuck clamped the center of the rod neck around the rotation center of the main axis of the head and tail seat, the rod neck diameter grinding processing.

Because of the reason of crankshaft technology design, it has a relatively large eccentricity in the distribution of length mass, if no measures are taken, the crankshaft in the processing rotation will appear uneven running phenomenon and produce centrifugal force conditions, so that the surface roughness of grinding processing will certainly be affected. Therefore, the counterweight device is formulated at the rear of the head and tail of the machine, which is adjusted by observing the driving motor current of the head and tail seat, so that the rotation almost stability of the head and tail seat can be improved and balanced. Because of the structure of the crankshaft itself, when the head and tail seat sclamps both ends of the crankshaft at the same time, the head and tail seat spun out of sync when rotating will cause the twist of the crankshaft and affect the processing accuracy. At present, in order to ensure the synchronization of the head and tail seat, crankshaft grinder head and tail seat of the transmission mode has two ways, one is through the synchronous shaft transmission, that is, the head seat as the main drive through a series of transmission chain to the tail seat, so that they achieve the crankshaft grinder head and tail seat chuck synchronization, to ensure that the crankshaft in the process of operation does not cause distortion phenomenon. This way of transmission manufacturing costs low, but inevitably there is a mechanical transmission chain too long gap and wear phenomenon, to the adjustment brought a lot of inconvenience. The other is to use head and tail seat rotation as two axes, using numerically controlled synchronization technology, so that the head and tail seat in the process of rotation of the rotation error to a minimum. Some in the use of head and tail seat rotation as a two-axis NUMERICAL synchronization technology manufacturers, in order to prevent equipment failure and sudden power failure caused by head and tail seat snitch, so that equipment damage and cause disexhaustation of products, the grinding wheel motor as a large diameter grinding wheel inertia after a sudden power failure as a generator use, the electricity issued to the head-tail motor as a temporary power supply, temporarily ensure that the head and tail seat can be rotated in a short period of time to prevent the expansion of the failure. At the same time to prevent the failure of the head and tail seat electrical system itself caused by the failure, in the head and tail seat mechanical part of the design has to go beyond the off-the-device as a protective device, in the actual operation due to the head and rear speed control system template failure caused by the head-and-tail seat failure 3 degrees, precisely because of the role of the device to prevent further expansion and preservation of nearly 300,000 yuan of workpiece scrap.

Crankshaft belongs to the slender shaft part, in the processing will form the intermediate sagging situation, some manufacturers in order to overcome this state in the machine tool design with mechanical, electrical, hydraulic measurement and other systems composed of crankshaft anti-sagging suspension system. The device is set to the third shaft in the cnc system of the machine, and its anti-crankshaft sagging lift force is controlled by the hydraulic proportional valve to maintain synchronization with the rotation angle of the head and tail seat.

With the development of numerical control technology, the improvement of the functional components of the machine tool, at present, a new equipment process has developed a follow-up grinding crankshaft, it can be honed on the same machine tool through a clamping can be at the same time grinding crankshaft spindle neck and connecting rod neck, and then do not need to use two equipments in turn to grind the crankshaft neck and connecting rod neck respectively.

The device is designed on the electrical system for full numerical control, full closed-loop feedback measurement control mode, in the mechanical design to break the structure distribution of the traditional grinder, the original head and tail and workpiece Z-axis movement changed to the grinding wheel frame movement and the head and tail seat and workpiece fixed, so the length of the bed can be designed shorter. Thanks to the X-axis horizontal slide principle, many factors such as machine deformation due to workpiece movement can be overcome and eliminated, and the rigidity of the machine is enhanced. The workbench table of the fixed workpiece is designed to tilt 20 degrees in the direction of the grinding wheel frame, so that the coolant can be easily drained and takes away a large number of grinding particles, ensuring the thermal stability of the machine tool and the workpiece due to the workbench tilt 20 degrees design so that the head and tail seat can be safely clamped on the workbench table of the fixed workpiece. Because of the different design structure, so the grinding method is also different from the general traditional crankshaft grinding, its spindle neck grinding method is cut-in grinding method, the grinding of the rod neck is the use of cut-in follow-up grinding method.