Newsgroups: comp.robotics
Path: brunix!uunet!pipex!bnr.co.uk!uknet!comlab.ox.ac.uk!sharkey
From: sharkey@robots.ox.ac.uk (Paul Sharkey)
Subject: Re: direct drive motors?
Message-ID: <1993Jun29.142303.22413@percy.robots.ox.ac.uk>
Originator: sharkey@percy.robots
Organization: Robotics Research Group, Engineering Science Dept, Oxford, UK.
References: <25998@mindlink.bc.ca> <C9Dnuz.2FF@brunel.ac.uk>
Date: Tue, 29 Jun 1993 14:23:03 GMT
Lines: 36


In article <25998@mindlink.bc.ca> Cliff_Lum@mindlink.bc.ca (Cliff Lum) writes:
>
>The motors if electric all need some sort of speed reduction. Best to use a

No electric motor needs to be coupled to a gearbox or belt or other
gear reducer.  

>gearhead that has no backlash such as those from HARMONIC Drive Technologies.
>I think this company also sells the motor and the gearhead as a unit.

HD servo units are very good but also on the expensive side. 

Gregory Vines <C9Dnuz.2FF@brunel.ac.uk> writes

>... There are several makes of
>direct-drive electric motors out there.  Try NSK, or Dynaserv.  In
>general you can get 10-400Nm at around 60 rev/min, with NO gear
>reduction!  However, expect them to be MASSIVE!

We have plenty of applications for directly driven electric motors.
True, if you want a lot of torque then you'll need a big motor
and the NSK Megatorque motors we have are too heavy for one person to
lift.  But for other applications motors weighing as little as 100g
can be used very effectively -- eg active force reflecting joystick
(eg BSP, Oxford), some camera positioning devices (eg NIST, US)

Paul.


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Dr Paul M Sharkey                 Office:  +44 (0)865 273 150   
Active Vision Laboratory          Lab:     +44 (0)865 273 168
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Dept Eng Sci, Univ of Oxford      Email:   sharkey@uk.ac.ox.robots
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