Rotary Actuator

Rotary Actuator

A unique rotary actuator has been developed, which forms the drive for the main axis of the manipulator arm. It basically consists of casing, slewing ring bearing, and a worm gearbox. The slewing ring bearing contains pre-loaded balls, which can take axial load, transverse load, and substantial amount of moment.
The inner race of the slewing ring bearing is bolted to a specially designed worm wheel, whereby it becomes an integral part of the bearing. The rotary actuator is driven by a PMDC motor through a self-locking gearbox, which is connected to the worm gear. The slewing ring bearing uses a Gothic ball track profile that is hardened and ground smoothly. The outer races are in two parts, dowelled together to render rated pre-loading to the bearing. On account of this pre-loading, the bearing can withstand axial load in both directions and at the same time can sustain radial load and substantial amount of moment. It is a low-speed bearing and exceptionally quiet in running due to zero clearance.
Four different configurations of the actuators have been developed. The turret actuator comprises a bearing of 220 mm diameter and can deliver a torque of 600 Nm at 2 rpm. The back arm actuator is actuated by a dual bearing drive of 140 mm diameter and is capable of delivering a torque of 1600 Nm at 0.5 rpm. The forearm actuator has been realised using a single 140 mm diameter bearing and can deliver a torque of 800 Nm at 0.5 rpm. The wrist roll action of the manipulator arm was accomplished using the same type of bearing coupled to a bevel pair, which in turn is driven by a geared motor.


            Four-point contact bearing     Bearing integrated with casing       Actuator mounted as arm turret

Salient Features

  • Electrically (24 V DC) operated

  • Four-point contact zero clearance pre-loaded ball bearing

  • Minimal backlash

  • Lightweight aluminium cast body

  • Unlimited 360o rotation

  • Orientation on any plane

  • Capacity (max): 1600 Nm @ 1 rpm

  • Bearing speed upto 100 rpm

  • Through central hole for cabling

  • Ideal for high precision indexing application

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