Patent GB-1534086-A (GB)
Title: Grinding wheel dressing devices for the form grinding of involute cylindrical gears
IPC: B24B53/085
Filed: 1976-08-13
Abstract: 1534086 Truing grinding wheels MAAG GEAR-WHEEL & MACHINE CO Ltd 13 Aug 1976 [19 Aug 1975] 33872/76 Heading B3D A dressing device for profiling a grinding wheel 5 for the form grinding of helically toothed involute cylindrical gears comprises a straight edge 5 arranged to roll on an arcuate guide 8. A tool-holder slide 15 carrying a typical or pointed dressing tool 16 is displaceable along a guideway 14 angularly adjustable according to the helix angle of the toothing to be ground and which has an involute motion imparted thereto from the movements of the straight edge. A pivot member 10 is constrained to pivot with the straight edge and a first crank slide 26 is reciprocable in dependence upon the pivotal movement of the pivot member. A crank 31 is mounted on a fixed pivot 32 and is connected by a first slider 29 to the first crank slide 26 and by a second slider 33 to a second crank slide 36. The second crank slide 36 is connected to the tool holder slide 15 to effect movement thereof along the slide 15 so as to modify the involute motion and the profile of the grinding wheel. The pivot member 10 is pivoted on a main shaft 2 supported by spaced bearings in a bed 1. A pivot plate 3 is fixed to the shaft between the bearings and has guides 6 for movement of an intermediate slide 4 movable transversely to the shaft. The straight edge 5 is mounted on guides 7 on the intermediate slide 4 and is connected by tension tapes to the arcuate guide 8 which is fixed to the bed 1 coaxial to the shaft 2. The straight edge 5 is connected by a slider block 11 to the pivot member 10 which also has a second slider block 12 connected to a cross slide 13 adjustable by a screw 18 along an end plate 17 of the intermediate slide 4 to the base circle radius of the gear to be ground, the cross slide mounting the guideway 14 for the tool holder slide 15 for angular adjustment according to the helix angle of the gear to be ground. The tool holder 15 is movable along the guideway by rotation of a screw 20 driven by a servo-motor 21. When the intermediate plate 4 is moved by a piston-andcylinder device 22, the straight edge rolls on the arcuate guide to impart an involute movement to the tool 16. In order to impart a longitudinal movement to the tool to accommodate the helix of the gear to be ground, a gear 25 secured to the shaft 2 engages a rack 27 on the first crank slide 26 which is movable along a guideway 26a and has the block 29 secured thereto and slidably in a guideway 30 of the crank 31 which is pivotally mounted on a portion 32 of the shaft 2. The second slider 33 on the crank is connected by an adjustable element 35 to the second crank slide 36 which is slidable along a guideway 36a and has a rack 37 meshing with a pinion 38 on a transmitter 39 having a mechanical or electrical connection 40 with the servomotor 21. If the element 35 is adjusted so that its shaft 34 is coaxial with the axis of pivot 32, the tool is moved only with an involute motion. With the guideway 14 adjusted to the helix angle of a gear to be ground and the element 35 adjusted to a distance E from the pivot 32, movement of the intermediate slide 4 causes movement of the second slider 36 and the transmitter 39 to effect a corresponding movement of the servo-motor 21 and hence a linear movement of the tool 16 to be added to its helical movement. Formulµ are given for determining the spacing of the block 33 from the shaft 2 and for the displacement of the tool 16 along the guideway. In another embodiment, the guideway 30 and block 29 are on the crank 31.