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Waist Drive for Electric Drive Robot

IP.com Disclosure Number: IPCOM000034563D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 3 page(s) / 115K

Publishing Venue

IBM

Related People

Brady, WA: AUTHOR [+2]

Abstract

This article describes a waist drive for an electric drive robot (EDR) which provides a backlash free rotary base for cylindrical or spherical motion robots. The waist drive assembly is shown in Fig. 1 in side view partly in section. It provides the EDR arm with 270 degrees of rotation about a vertical axis. Due to the length of the arm, backlash-free operation is essential in obtaining the required position tolerances. Main shaft A is shown within the main housing. The main shaft is the output element of the drive. It is supported by two sets of tapered roller bearings B. The bearings can be adjusted for the proper preload of the system using bearing lock nut C. The drive gear R is attached to the lower end of the main shaft.

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Waist Drive for Electric Drive Robot

This article describes a waist drive for an electric drive robot (EDR) which provides a backlash free rotary base for cylindrical or spherical motion robots. The waist drive assembly is shown in Fig. 1 in side view partly in section. It provides the EDR arm with 270 degrees of rotation about a vertical axis. Due to the length of the arm, backlash-free operation is essential in obtaining the required position tolerances. Main shaft A is shown within the main housing. The main shaft is the output element of the drive. It is supported by two sets of tapered roller bearings B. The bearings can be adjusted for the proper preload of the system using bearing lock nut C. The drive gear R is attached to the lower end of the main shaft.

(Image Omitted)

An adapter plate S is fastened to the housing and supports a motor pivot plate 0, as shown in Fig. 2 which is a section across A-A of Fig. 1. The drive motor assembly E is securely bolted and doweled to the pivot plate. Fig. 3 is a side view partly in section of the drive motor assembly. The assembly is a uniquely designed package. The pancake style servo motor E has a tachometer and optical encoder T mounted directly to the motor shaft to provide velocity and position feedback. The gear head housing is attached to the motor face. The gear head contains a high ratio (100:1) gear drive called harmonic drive which is comprised of wave generator H, circular spline G and flex spline F. The drive pinion J is directly attached to the gear drive output component (flex spline) F. This further eliminates any potential backlash. Once the motor is mounted to the motor pivot plate, the drive pinion receives added support via the trunnion pin K an...