Patent GB-1395209-A (GB)
Title: Method and apparatus for producing bearing races
IPC: B24B5/12
Filed: 1972-12-11
Abstract: 1395209 Grinding NIPPON SEIKO KK 11 Dec 1972 57026/72 Heading B3D A method of producing bearing races from a pipe of suitable material comprises bringing the inside and outside surfaces of a portion of the pipe to the profiles required for a bearing race by the use of respective suitably profiled grinding tools 33, 38 and then severing the portion from the pipe to produce a bearing race. A machine for carrying out the method has a spindle means A, Fig. 1, for holding and rotating the tubular blank, a grinding wheel spindle means B for a wheel 33 for grinding the outer surface of the blank, a grinding wheel spindle means C for a wheel 38 for grinding the inner surface of the blank, grinding wheel spindle means D for a wheel 90 for grinding the end surface of a finished race cut from the blank by a flange on the wheel 33, means 75 for feeding the blank, and means E for feeding the blank from one end thereof and holding the finished rack during grinding of its end surface by the wheel 90. The spindle means A, Figs. 1 and 4, consists of a spindle 4 supported in bearings in a housing 5 and at each end having a chuck 9, 10 having a part 12 actuated by a piston 11 to grip the tubular blank 3. The oil for actuating the pistons is supplied through passages 17, 18, 19. A portion 14 of the rear chuck 10 is adapted to receive a belt drive for rotating the spindle 4. The grinding wheel spindle means B for the wheel 33 for grinding the outer surface of the blank has a spindle 25, Figs. 1 and 3, which is belt driven from a motor 27 and mounted on a base 24 movable on a part 23 of the bed 1 by a feed means 32. The outer surface of the grinding wheel is continuously dressed by a rotary diamond dresser 29 on a spindle 30 driven by a motor 31 and mounted on a slide 36. As the wheel 33 is dressed, the base 36 of the dresser is moved towards the grinding wheel, and the base 24 is moved towards the blank being ground after grinding of a number of races. The spindle 25 for the grinding wheel 33 also carries a rotary diamond dresser 39 for the inner surface grinding wheel 38 on the spindle means C. The grinding wheel spindle means C, Figs. 1 and 6, has a base 41 slidable in a direction perpendicular to the axis of the blank 3 on a base 40 on the bed 1. A spindle base 45 is secured to base 41 and reciprocatingly supports a head 44 for a spindle carrying the grinding wheel 38 for the inner surface of the blank. The head 44 is movable on the base 41 to the position shown for a dressing operation in which a piston 47 abuts one end 50 of an inner cylinder 48 in contact with a front cover of an outer cylinder 46; to a second position in which the piston abuts the other end of the inner cylinder for a grinding operation; and to a third position in which the inner cylinder abuts the rear cover 51 of the outer cylinder during automatic changing of a grinding wheel by devices 52a, 52b. A cylinder 53, Fig. 7, is secured to the slide 41 and has a piston integral with the rod of a piston in a cylinder 54 for reciprocating the slide 41. The cylinder 54 is formed with a part 55 slidable on the base 40 by means of a screw-and-nut 56, 57 driven by a device 42. The front feeder means E has a slide 62 slidable on a base 61 on the slide 41 and has a spindle parallel to the grinding spindle. A cylinder 59 moves the slide 62 through the same distance as the stroke of cylinder 54. The cylinder 53 effects a stroke b slightly greater than the clearance a between the wheel 38 and rotary dresser 39 to effect a dressing operation. A body 63 is reciprocatable on the slide 62 by a power cylinder 64 and carries a motor 65 for rotating a feeder shaft 66 having a magnet chuck 74 holding a piece 76 for engaging the end of the tubular blank 3, Fig. 8. The cylinder 59 effects movement of the slide so that, in one position, the chuck 74 is aligned with the spindle 4 for drawing the tubular blank therethrough to a grinding position, and in another position, the finished race is held for grinding by the wheel 40, Fig. 1. The axial position of the magnet chuck 74 is determined by the position of pistons 29, 85 in the cylinder 64. The grinding wheel spindle means D has its spindle carrying the grinding wheel 90 at right angles to the axis of spindle 4 carrying the tubular blank 3 and is fed axially of the blank by a screw-and-nut mechanism driven by bevel gearing and a feed box 92. The spindle 43 for the inner grinding wheel 38, Fig. 10, is formed with an annular chamber to which cooling fluid is supplied through a pipe 107 and passed through openings 105 to the grinding wheel. Both the outer grinding wheel 33 and the inner grinding wheel 38 are formed in two portions 33A, 33B, Fig. 14, and 38A, 38B, Fig. 17, so that both a rough grinding and a finish grinding is effected by each wheel, and the outer wheel 33 has a flange 33c for severing a finished race 3a while a part of the blank is being finished ground and another part rough ground. The wheels are formed so that either the outer race or the inner race of a bearing is ground. In operation, the tubular blank 3 is passed through spindle 4 so that a length equal to two races projects therefrom, the end of the blank abutting the piece 76 held by the chuck 74, the chucks 11, 12 then gripping the blank and the piece 76 being retracted. The grinding wheel 33 is fed in to grind the outer surface of the blank and at the same time the grinding wheel 38 is advanced towards the blank. Thereafter, as the outer grinding wheel is retracted, the inner grinding wheel forms the inner surface and is then retracted. At this time, a part at the end of the blank is finish ground and the adjacent part rough ground. The nose piece 76 is advanced to contact the end of the blank and the chucks 10, 11 opened. The piece 76 is then magnetized and the blank pulled out of the spindle and regripped. When the outer grinding wheel is advanced, the end piece is severed by the flange 33c, the rough ground part is finish ground and the next part rough ground. The severed race is rotated by the magnet chuck 74 and transported so that its severed end can be ground by the wheel 90. A similar sequence occurs for grinding of inner races.