Measurement and prediction of spin losses in the EHL point contacts of the full toroidal variator

Newall, Jonathan; Lee, Adrian V.

doi:10.1016/s0167-8922(03)80105-0

Cited by 21 publications

(9 citation statements)

References 2 publications

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“…However, most of these methods adopted excessive simplifications which narrows the scope of their applications. Nevertheless, the method proposed by Carbone et al [25] has been widely accepted [17,21,33] because of its reasonable simplifications and acceptable precision in comparison with experimental results [9,34]. Therefore, this method is adopted to calculate the efficiency of the Logarithmic CVT which is similar to the Toroidal CVT.…”

Section: Computational Methodmentioning

confidence: 99%

“…21 and 23 are the spin ratios of the input and output tractions, respectively. From (34), it is obvious that the spin ratios of the Logarithmic CVT cannot equal zero precisely because of the sliding coefficients. However, comparing with the spin ratios of the Half-Toroidal CVT [25] shown in (35), it can be seen that the spin ratio of the Logarithmic CVT is far less than that of the Toroidal CVT, which directly promotes the efficiency:…”

Section: Computational Methodmentioning

confidence: 99%

See 1 more Smart Citation

A Mathematical Method for Eliminating Spin Losses in Toroidal Traction Drives

et al. 2015

Mathematical Problems in Engineering

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The efficiency of the original Toroidal continuously variable transmission (CVT) is limited due to the spin losses caused by the different speed distribution in the contact area. To overcome this drawback, this paper replaces the original working surface with a new surface derived from a differential equation and proposes a novel Logarithmic CVT. Equations and ranges of the transmission ratio range, half-cone-angle, and conformity ratio, which are essential geometrical parameters of the Logarithmic CVT, are derived. A set of geometrical parameters is further recommended. With such geometrical parameters, the transmission ratio range of the Logarithmic CVT is as wide as that of the Half-Toroidal CVT. The two types of CVTs are compared with each other in terms of efficiency based on a widely accepted computational model. The results show that efficiency of the Logarithmic CVT is higher than that of Half-Toroidal CVT except for some particular situations because of the thrust bearing losses.

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Section: Computational Methodmentioning

confidence: 99%

Section: Computational Methodmentioning

confidence: 99%

A Mathematical Method for Eliminating Spin Losses in Toroidal Traction Drives

et al. 2015

Mathematical Problems in Engineering

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“…Therefore, this special condition is always called zero-spin condition. A large number of studies [9][10][11][12] have shown that spin losses affect the traction performance of t-CVT significantly. Therefore, decreasing the spin losses can improve the reliability and fatigue life [13] , increase the power density and torque capacity [7,14] , and greatly improve the traction efficiency of traction CVT [15][16][17] .…”

Section: Figurementioning

confidence: 99%

Design Principles and Traction Performance of a Novel Zero-spin Rolling Conical Traction Continuously Variable Transmission

Cao

2020

Preprint

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In the existing traction continuously variable transmission (CVT), half toroidal CVT (HT-CVT) is considered to have a better traction performance. However, the HT-CVT has the spin losses due to its structural limitations, which significantly influences the traction efficiency. In this paper, the kinematic qualities and contact models of a novel zero-spin rolling conical CVT (RC-CVT) are studied, and then the rollers and conical disks are compactly designed through the proposed design principles. Subsequently, the transmission efficiency is investigated by using a detailed numerical model and compared with HT-CVT. Based on these computational models and parameters, the practical spin ratio, spin momentum and traction efficiency of RC-CVT are calculated and compared with HT-CVT. The results show that the practical spin ratio and spin momentum of RC-CVT are much smaller than that of HT-CVT, and the efficiency on fixed transmission ratio is consequently higher than that of HT-CVT.

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“…There is substantial number of researches in the field of CVT. Jacod et al [5] and Newall and Lee [6] presented models to calculate the traction coefficient of the lubricating oil in the toroidal CVT. Attia et al [7] formulated the contact stress between toroidal CVT elements using Hertz law, and found the parameters which impact the contact stress.…”

Section: Introductionmentioning

confidence: 99%

Modelling and Optimization of Toroidal Continuously Variable Transmission in ECE Driving Cycle

Delkhosh

Foumani

2012

IJE

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In the present study, the aim is to optimize full and half-toroidal continuously variable transmission (CVT) in order to minimize the vehicle fuel consumption (FC) in ECE driving cycle. First, a model for both toroidal CVT efficiency is presented. A simulation model of the considered power train is described. The control strategy of CVT speed ratio based on minimizing the vehicle FC is introduced, and the algorithm of calculating the vehicle FC is shown. Afterwards, both types of CVT are optimized using Particle Swarm Optimization method (PSO) with the aim of minimizing the vehicle FC in ECE driving cycle, and the optimized geometries are achieved. It is found that a remarkable fuel economy can be achieved through optimization of each type. The effects of the vehicle weight on the optimized geometries are examined. It will be shown that, the optimized geometry of full-toroidal type is not strongly influenced by the vehicle weight, while the optimized geometry of half-toroidal one varies through variation of the vehicle weight.

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Measurement and prediction of spin losses in the EHL point contacts of the full toroidal variator

Cited by 21 publications

References 2 publications

A Mathematical Method for Eliminating Spin Losses in Toroidal Traction Drives

A Mathematical Method for Eliminating Spin Losses in Toroidal Traction Drives

Design Principles and Traction Performance of a Novel Zero-spin Rolling Conical Traction Continuously Variable Transmission

Modelling and Optimization of Toroidal Continuously Variable Transmission in ECE Driving Cycle

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