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Journal ArticleDOI

Analysis of a cycloid speed reducer

01 Jan 1983-Mechanism and Machine Theory (Pergamon)-Vol. 18, Iss: 6, pp 491-499

AbstractThe cycloid speed reducer has the advantages of compactness, large ratios and high efficiency. Very little published information is available on its analysis and design. In this paper, a procedure to calculate the forces on various elements of the speed reducer as well as the theoretical efficiency is presented. Also the effects of design parameters on forces and contact stresses are studied which will aid optimal design of this type of speed reducer. more

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Journal ArticleDOI
Abstract: A cycloid speed reducer is one of the rotational speed regulation devices of the machinery. It has advantages of the higher reduction ratio, the higher accuracy, the easier adjustment of the transmission ratio and the smaller workspace than any other kinds of the reducer. This paper proposes a simple and exact approach for the lobe profile design of the cycloid plate gear, which is a main part of the cycloid reducer, by means of the principle of the instant velocity center in the general contact mechanism and the homogeneous coordinate transformation. It is considered the four types of the cycloid reducers in this study: the stationary ring gear type epicycloid reducer, the rotating ring gear type epicycloid reducer, the stationary ring gear type hypocycloid reducer and the rotating ring gear type hypocycloid reducer. Design examples for the four types of the cycloid reducers are presented to simulate the operation and to demonstrate the feasibility of this approach using a computer-aided program developed on C++ language.

87 citations

Cites background from "Analysis of a cycloid speed reducer..."

  • ...Malhotra and Parameswaran [2] studied the effects of design parameters on forces for various elements of the cycloid speed reducer as well as the theoretical efficiency....


Journal ArticleDOI
Abstract: Compared with common speed reducers, the cycloidal ones (also known as cycloid drives) cover a wider range of transmission ratios, have a higher load-carrying capacity, are smaller, exhibit a smoother running and a good efficiency. These characteristics make them attractive for industrial applications, especially for robotics applications, machine tools and linear axis positioning in assembly machinery. In this paper, a theoretical and experimental investigation on an innovative cycloidal speed reducer will be presented. The typical cycloid drive has a planet wheel, the profile of which is the inner offset of an epitrochoid, meshing with cylindrical rollers connected to the case. This reducer, on the contrary, has an external ring gear, the transverse profile of which is the external offset of an epitrochoid, and engages with the planet wheel by means of cylindrical rollers. This paper will investigate the structural characteristics and the kinematical principles of this type of reducer. A theoretical approach based on the envelope theory (following Litvin’s approach) will be developed and compared with a development of Blanche and Yang’s approach. Furthermore, a simplified procedure to calculate force distribution on cycloid drive elements, as well as its power losses and theoretical mechanical efficiency will be presented. The effects of design parameters on the values of the forces will be studied, for an optimal design of this type of reducer. The theoretical model will be then tuned using the results of tests on a specific rig. As a result of the experimental tests, the reducer mechanical efficiency dependency on speed and torque will be described. The aim of this work is to perform the fine tuning of a theoretical model in order to predict the operating behavior of the cycloid drive, and to improve its design procedure.Copyright © 2007 by ASME

78 citations

Journal ArticleDOI
Abstract: A new design of a two-stage cycloidal speed reducer is presented in this paper. A traditional two-stage cycloidal speed reducer is obtained by the simple combination of singlestage cycloidal speed reducers. A single-stage reducer engages two identical cycloid discs in order to balance dynamical loads and to obtain uniform load distribution. Consequently, the traditional two-stage reducer has four cycloid discs, in total. The newly designed two-stage cycloidal speed reducer, presented in this paper, has one cycloid disc for each stage, that is, two cycloid discs in total, which means that it is rather compact. Due to its specific concept, this reducer is characterized by good load distribution and dynamic balance, and this is described in the paper. Stress state analysis of cycloidal speed reducer elements was also realized, using the finite elements method (FEM), for the most critical cases of conjugate gear action (one, two, or three pairs of teeth in contact). The results showed that cycloid discs are rather uniformly loaded, justifying the design solution presented here. Experimental analysis of the stress state for cycloid discs was realized, using the strain gauges method. It is easy to conclude, based on the obtained results, that even for the most critical case (one pair of teeth in contact) stresses on cycloid discs are in the allowed limits, thus providing normal functioning of the reducer for its anticipated lifetime. [DOI: 10.1115/1.4004540]

67 citations

Journal ArticleDOI
Abstract: The cycloidal gear reducer is a compact, high-ratio, and low-backlash speed reduction device. It has been commonly used for transmitting motion and torque in machinery. This paper presents the design of a new two-stage cycloidal speed reducer with tooth modifications. The topological structure of cycloidal drives is discussed and analyzed with the aid of graphs. New cycloidal gear reducers are enumerated through the topological analysis and a new two-stage cycloidal gear reducer with simpler structure is then proposed. The design of the proposed cycloidal gear reducer is also performed, including profile generation and modifications. Subsequently, kinematic errors are analyzed by using the tooth contact analysis, and the results caused by different combinations of the gear profile modifications are presented quantitatively. Finally, based on the analysis, a mock-up of the cycloidal gear drive is constructed to validate the feasibility of the new mechanism.

50 citations

Journal ArticleDOI
TL;DR: This paper presents review of high precision reducers (HPRs) for industrial robots driving 4th industrial revolution, and provides HPRs market along with industrial robots, and principle, characteristics, and three main performances of H PRs are discussed.
Abstract: New industrial revolution - “The 4th industrial revolution” must be a remarkable milestone for the second decade of the twenty-first century. Many countries are competing to innovate their manufacturing chains for eco-friendly and energy-efficient productions. Although this green or sustainable manufacturing system evolves under the support of cyber-physical system (or digital twin) based on ICT technology, industrial robots also play important roles in this speedy, flexible and effective manufacturing chains. Recently, low-cost industrial robots or collaborative robots, are rising in a highly interactive environment with humans. Although an industrial robot consists of many important components such as mechanical parts (kinematic structure and reducer) and electric parts (servo motor, driver, sensors, and controller), precision reducer takes approximately 25% of material-cost and governs important performance indices of industrial robots. This paper presents review of high precision reducers (HPRs) for industrial robots driving 4th industrial revolution. First, we provide HPRs market along with industrial robots. According to previous studies, HPRs for industrial robots can be classified based on their principles: planetary reducer, cycloid reducer, and harmonic drive (HD). Then, principle, characteristics, and three main performances (hysteresis, rotational transmission error (RTE) and efficiency) of HPRs are discussed. In addition, compensation methods overcoming accuracy limits of HPRs are summarized. Finally, other applications of HPRs except industrial robots are presented.

47 citations