Cam grinding machine and cam grinding method

A cam grinding machine configured to grind a composite cam,

• the composite cam including a first cam having a lift amount that varies, the lift amount being a distance from a rotation axis of the composite cam to an outer peripheral surface of the first cam, and a second cam having a lift amount that varies, the lift amount being a distance from the rotation axis of the composite cam to an outer peripheral surface of the second cam,
• the first cam and the second cam being coaxially disposed adjacent to each other in an axial direction, and
• the first cam and the second cam having shapes corresponding respectively to first cam lift data and second cam lift data that are different from each other,
• the cam grinding machine comprising:
• a bed;
• a workpiece rotating device mounted on the bed, the workpiece rotating device being configured to control a phase of the composite cam about the rotation axis to rotationally drive the composite cam;
• a grinding wheel device mounted on the bed, the grinding wheel device including a rotary grinding wheel;
• a traverse moving device configured to control a position of the grinding wheel relative to the composite cam in the axial direction to perform traverse movement of the grinding wheel relative to the composite cam;
• a plunge moving device configured to control a position of the grinding wheel relative to the composite cam in a direction intersecting with the axial direction to perform plunge movement of the grinding wheel relative to the composite cam;
• and
• a controller configured to control the workpiece rotating device, the traverse moving device, and the plunge moving device, wherein
• the controller includes:
• a common surface setting unit configured to acquire and store a phase range of a common surface in which the lift amount of the first cam and the lift amount of the second cam are equal to each other, based on the first cam lift data in which the lift amount at each phase of the first cam is set and the second cam lift data in which the lift amount at each phase of the second cam is set;
• a first cam grinding unit configured to control the workpiece rotating device and the plunge moving device to grind the first cam;
• a first common surface grinding unit configured to control the workpiece rotating device and the traverse moving device to move the grinding wheel from a common surface of the first cam to the common surface of the second cam and to grind the common surface;
• a second cam grinding unit configured to control the workpiece rotating device and the plunge moving device to grind the second cam;
• a second common surface grinding unit configured to control the workpiece rotating device and the traverse moving device to move the grinding wheel from a common surface of the second cam to the common surface of the first cam and to grind the common surface;
• and
• an overall operation unit configured to set actuations such that the first cam grinding unit, the first common surface grinding unit, the second cam grinding unit, and the second common surface grinding unit are actuated in this order.