Kamo Seiko Corporation

Kamo, Japan

Kamo Seiko Corporation

Kamo, Japan
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Terada H.,Yamanashi University | Kobayashi M.,Yamanashi University | Imase K.,Kamo Seiko Corporation
Mechanisms and Machine Science | Year: 2014

To realize the no-backlash transmission element for wearable human assist robots, a trochoidal gear reducer with a slipping rollers type torque limiter has been developed. This reducer is a kind of a pin gear with planetary motion. That roller-train is fixed only by friction force to slip under an overload. And a preload mechanism has been developed. This mechanism consists of an outer race and a preload generator which have taper contact sections to generate a uniform preload. Also, a calculation method of a trochoidal gear tooth profile by use of polar complex vector geometry is proposed. Then, using the prototype reducer, it is proved that slip occurs in the set torque, and that reducer can rotate without backlash. And it is clear that has the sufficient performances for actuator of wearable human assist robots. © Springer Science+Business Media Dordrecht 2014.


Ohta H.,Nagaoka University of Technology | Kurita M.,Nagaoka University of Technology | Kishi K.,Kamo Seiko Corporation
Journal of Tribology | Year: 2014

This article deals with the effects of the contact ratio Îμ on transmission errors of trochoidal gears (which consist of a roller gear anda cam gear). First, the experiments and multibody analysis (MBA) for the transmission errors of two types of single-row trochoidal gears (types A and B gears) were carried out. The type A gear is a commercial trochoidal gear with =1.1 and the type B gear is a trochoidal gear with ‰=2.1 (by increasing the number of teeth). The experimental and MBA results showed that the peak-to-peak value TEP-P of the transmission errors of the type B gear (with =2.1) was lower than the type A gear (with =1.1). The TEP-P of types A and B gears increased as the rotational speed of the roller gear increased. However, the increasing rate of the measured TEP-P of the type B gear due to an increase of the rotational speed was less than that of the type A gear. Increasing the contact ratio due to an increase in the number of teeth in a single-row trochoidal gear (such as a type B gear) decreases the strength of the teeth and rollers. To overcome this problem, as a new transmission error reduction method, a double-row trochoidal gear (type C gear), having two times the contact ratio of the type A single-row trochoidal gear was presented and its transmission error was examined. The experimental and MBA results showed that the TEP-P of the transmission errors of the type C double-row trochoidal gear were lower than that of the type A single-row trochoidal gear. Therefore, it is clear that using a double-row trochoidal gear is effective for reducing the transmission errors of trochoidal gears.© 2014 by ASME.


Ohta H.,Nagaoka University of Technology | Yamakawa A.,Nagaoka University of Technology | Katayama Y.,Kamo Seiko Corporation
Journal of Tribology | Year: 2012

This article deals with the effects of eccentricity on transmission errors of trochoidal gears (consisting of a roller gear and cam gear). For the tests, three types of roller gears and three types of cam gears (which had different eccentricity) were used. The experimental results showed that the peak to peak values of transmission errors had a tendency to be greater under a larger eccentricity. The measured transmission error waveforms fluctuated with periods 1/f r, 1/f c and 1/z rf r (in which f r and f c are the rotational frequencies of the roller gears and cam gears, while z r is the number of rollers). The peaks with nf r (n=1, 2, 3,⋯), nf c, nz rf r, nz rf r ± mf r (m=1, 2, 3,⋯) and nz rf r ± mf c appeared in the measured transmission error spectra. The amplitudes of peaks with f r and nz rf r ± mf r increased as e r increased, while the amplitudes of peaks with f c and nz rf r mf c increased as e c increased. The transmission errors of test gears with eccentricity were estimated by the multibody analysis (MBA). A reasonable correlation exits between the calculated results obtained by the MBA and the measured experimental results. Copyright © 2012 American Society of Mechanical Engineers.

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