GB1253685A - Grinding machine - Google Patents

Abstract

1,253,685. Grinding. HEALD MACHINE CO. 28 Feb., 1969 [4 March, 1968], No. 10892/69. Heading B3D. A grinding machine comprises a workhead 12 for holding and rotating a workpiece 24 having a portion which is to be formed with a surface of revolution of non-cylindrical form; a wheelhead 13 for rotating an abrasive wheel 17 having a surface of revolution the profile of which is complementary to that of the surface to be formed on the workpiece; feed means to move the workhead and wheelhead relative to one another to introduce the abrasive wheel to the workpiece for a plunge grind with a predetermined controlled force; a dresser 14, having an operative surface the profile of which is complementary to that of the abrasive wheel surface, located adjacent the workhead and wheelhead; and means serving to introduce the abrasive wheel 17 to the dresser for restoring the abrasive wheel accurately to its original profile after the plunge grind. As described, the workpiece 24 is a ball race having a ball groove 38 and seal grooves 45, 46. The race is rotated during grinding by a platen 33 having a recess 34. The wheel 17 comprises a portion 39 for grinding the groove 38 and portions 41, 42 for grinding the grooves 45, 46. The wheel 17 is mounted on a sipndle 16 of the wheelhead 13 which is itself mounted for movement axially and transversely of the spindle. A second grinding wheel 18 is provided on the spindle 16 for finish grinding of the groove 38 and a second dresser 15 is provided for this wheel. In operation a workpiece 24 is automatically fed to the position shown in the workhead 12 and rotated by the platen 33. The wheelhead 13 is first moved axially from the dashed-line position to align the wheel 17 with the workpiece and is then moved transversely under low force firstly without, and then with, damping, then under high force, and finally held in position for sparking out. The wheel 17 is then withdrawn transversely and the wheelhead moved axially to align the wheel 18 with the groove 38. The wheel 18 is then moved transversely with the wheel 17 within the recess 34 as shown, first under low force, then under high force, and then held in position for sparking out. The wheelhead 13 is then moved transversely and then axially to align the wheels with the dressers 14, 15. A wheel 29 of the dresser 14 is pivoted into contact with the wheel 17 to dress it as coolant is supplied. The wheel 29 has a surface corresponding to that of the workpiece and is made up of a number of diamonds embedded in a matrix of e.g. sintered copper powder. The wheel 18 is then dressed by the dresser 15 comprising a diamond 32 moved in an arc.