Browse Prior Art Database

Low Inertia Stepper Motor

IP.com Disclosure Number: IPCOM000089519D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Lutz, H: AUTHOR [+3]

Abstract

Stepper motors used for high-speed start/stop operation should have a relatively high torque and low inertia. The quality of such stepper motors can thus be defined in terms of the torque-to-inertia ratio.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Low Inertia Stepper Motor

Stepper motors used for high-speed start/stop operation should have a relatively high torque and low inertia. The quality of such stepper motors can thus be defined in terms of the torque-to-inertia ratio.

The illustrated stepper motor has a magnetized rotor, with a DC flux entering across the front face of the rotor and exiting via the teeth of the lateral area. The shape of the rotor is such that the front face and the effective lateral areas are identical. This rotor differs from other rotors of this type in that, instead of a solid rotor, a rotor with a conical bore is used. This bore does not affect the DC flux which remains below saturation in all rotor areas.

This bore reduces the inertia of the rotor by up to 20%, the torque remaining unchanged, so that the quality of such a stepper motor is improved by up to 20% over that of stepper motors with solid cylindrical rotors.

Conical bore rotor 1 is fixed to shaft 2 which is supported in ball bearing 3 and needle bearing 4. The open end of rotor 1 supports itself against shaft 2 by means of a plastic disk 5. The DC flux is generated by means of winding 6 which is wound around core 7. Core 7 together with motor housing 8, the four stator poles 9 and rotor 1 forms a magnetic circuit for the DC flux. The stator windings are represented by 10.

1

Page 2 of 2

2

[This page contains 1 picture or other non-text object]