Patent GB-1376138-A (GB)
Title: Gear lapping machines
IPC: B23F19/02
Filed: 1971-12-06
Abstract: 1376138 Lapping gears GLEASON WORKS 6 Dec 1971 [16 Dec 1970 (2)] 56433/71 Heading B3D  A gear lapping machine for running together in mesh a pair of bevel or hypoid gears comprises a gear head assembly 50 having a spindle 20 for one of the gears, the spindle being movable in two mutually perpendicular directions P, E transverse to its axis and in a direction parallel to its axis to vary the contact between the teeth of the gears from mean positions to positions adjacent the tips of the gears and lengthwise of the teeth. The assembly 50 is adjustable along slides 48 on a cross-slide 42 which, in turn, is adjustable transversely along slides 40 as a frame 14. The spindle 20 extends into a lapping chamber 16 in which is a non-adjustable spindle 18 for a pinion, the spindle being rotatable by a bell-drive 26 from a constant speed eddy current motor 24. The gear spindle 20 is rotatable by a belt drive 34 from an hydraulic motor 32 which applies a braking torque to the spindle during lapping. The spindle and the means for moving it in the three directions are mounted on a slide 56 which is vertically adjustable along guideways 54 on the assembly 50. The spindle is rotatably mounted in a housing 112, Fig. 5, which is pivotably mounted on a shaft 122 in a bracket 120 in turn pivotally mounted on a shaft 132 mounted in lugs 134 on the slide 56. The spindle is movable in the E direction by pivotal movement about the shaft 122 against the action of a spring 118 by the rod 124 of a linear actuator 66 bearing by way of a spherical bearing 128 against a thrust pad 126 in the spindle housing 112, and is movable in the P direction by a similar arrangement moving the bracket 120 about the shaft 132. Axial movement of the spindle is effected by a similar linear actuator 66 having its rod 124 abutting a spherical bearing 130, Fig. 6, for moving an arm 140 about a pivot 142, the arm having a second spherical bearing 144 with a slide 150 to move the bracket 120 carrying the spindle housing 112 axially. Each actuator 66 consists of a rod 84, Fig. 3, which is formed with a square end 88 engaging a complementary socket 90 and a ball screw thread 86 engaging a nut 82 secured to a sleeve 78 rotated by a wheel 76 meshing with a worm 74 driven by a stepping motor 68, Fig. 2. Each actuator has means for determining when it has been returned to an initial position consisting of a dog 96 secured to the sleeve 78. The dog has surfaces 98, Fig. 4, which are engageable by spring pressed plungers 104 when the actuator is in its initial position, limit switches indicating where the plungers are engaging the surfaces. The plungers are disengaged from the surfaces by fluid pressure supplied to chambers 104. In operation, a gear and pinion are mounted on the shafts 18, 20, respectively, and a controlling drum 30 is actuated to advance the assembly 50 so that the gear engages the pinion; the pinion may be rotated at a slow speed to ensure meshing. After advance into tight meshing, the spindle 20 is retricted to set a predetermined backlash between the pinions. Spindle 18 is then rotated in a direction for rough lapping the reverse or coast side of the teeth, the hydraulic motor 32 braking the spindle 20 for a preset rough lapping load. Thereafter, no further lapping of the reverse side is effected or the reversee side is finish lapped using a "feather" lap sequence or is finish lapped by two additional cycles in which a first tip lapping is effected, in which the contact between the teeth is moved by actuation of the actuators 66 to be high on the teeth of one of the gear members, and a second tip lapping is effected, in which the contact is high on the teeth of the other member. When the reverse side of the teeth have been lapped, the sequence is repeated for lapping the front side of the teeth. The cycles are automatically controlled and may be timed so that parts of the cycle are longer than others, e.g. the toe of the gear tooth may be lapped for a longer period of time than the heel.