Investigation of Compliant Ortho-Planar Springs for Rotational Applications

2006 ◽  
Author(s):  
Nathan O. Rasmussen ◽  
Robert H. Todd ◽  
Larry L. Howell ◽  
Spencer P. Magleby
Keyword(s):  
Continuously Variable Transmission ◽  
Direct Result ◽  
Design Parameters ◽  
Stress Concentrations ◽  
Lateral Instability ◽  
Lateral Buckling ◽  
Primary Motivation ◽  
Variable Transmission

This paper explores the feasibility of using compliant-ortho-planar springs (COPS) for rotational applications. The primary motivation is the application of COPS to a rubber v-belt continuously variable transmission (CVT). Although stresses and stress concentrations are important for the design of a COPS, this paper will focus on the behavior of a COPS resulting specifically from its rotation. This paper focuses on issues related to stress stiffening and lateral instability. Both phenomena are a direct result of the inertial loads a COPS would experience in a rotating environment. The results show how stress stiffening and lateral buckling are influenced by design parameters. Conclusions and recommendations for further research are presented.

FRICTIONAL PROBLEMS IN CONTINUOUSLY VARIABLE TRANSMISSION BELT DRIVES

Tribologia ◽  
2017 ◽  
pp. 93-100 ◽  
Author(s):  
Wojciech SZCZYPIŃSKI-SALA ◽  
Krzysztof DOBAJ ◽  
Adam KOT
Keyword(s):  
High Performance ◽  
Angular Speed ◽  
Continuously Variable Transmission ◽  
Design Parameters ◽  
Belt Drive ◽  
Power Losses ◽  
Belt Drives ◽  
Variable Transmission ◽  
Drive Systems ◽  
The Impact

The article describes the results of the research carried out on the evaluation of the influence of friction pairs (rubber belt – belt pulley in belt drive) on the ability to transmit power. In order to determine the characteristics of the belt drive operation, measurements were made on a real belt drive from the drive train of a light two-wheeled vehicle. The measurement was carried out in conditions of changes in the dynamic load. The measurements of the belt slip on the belt pulley within the whole range of the changes of gear ratios and angular speed of the engine were made. During the tests, belts made from various rubber mixtures were compared. The values of the friction coefficients between the surface of belts and the belt pulley were measured. Model analyses of the impact of belt slip on the wheel related to the temperature of Belt drive elements were also made. Generally, one can ascertain that, in belt drive systems, power losses are a combination of speed losses and torque losses. The increase in the efficiency of belt drives is possible by decreasing power losses. It is possible to obtain the high performance of continuously variable transmission belt drives with a V- belt solely with the proper choice of the design parameters, which is possible only after the exact recognition of the operational characteristics unique to this class of belt drive systems.

A Validated Modular Model for Hydraulic Actuation in a Pushbelt Continuously Variable Transmission

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Stan van der Meulen ◽  
Rokus van Iperen ◽  
Bram de Jager ◽  
Frans Veldpaus ◽  
Francis van der Sluis ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
First Principles ◽  
Closed Loop ◽  
Low Complexity ◽  
High Accuracy ◽  
Continuously Variable Transmission ◽  
Design Parameters ◽  
Actuation System ◽  
Modular Model ◽  
Variable Transmission

A reduction in the fuel consumption of a passenger car with a pushbelt continuously variable transmission (CVT) can be established via optimization of the hydraulic actuation system. This requires a model of the dynamic characteristics with low complexity and high accuracy, e.g., for closed-loop control design, for closed-loop simulation, and for optimization of design parameters. The hydraulic actuation system includes a large number of hydraulic components and a model of the dynamic characteristics is scarce, which is caused by the complexity, the nonlinearity, and the necessity of a large number of physical parameters that are uncertain or unknown. In this paper, a modular model for the hydraulic actuation system on the basis of first principles is constructed and validated, which is characterized by a relatively low complexity and a reasonably high accuracy. A modular approach is pursued with respect to the first principles models of the hydraulic components, i.e., a hydraulic pump, spool valves, proportional solenoid valves, channels, and hydraulic cylinders, which reduces complexity and improves transparency. The model parameters are either directly provided, directly measured, or identified. The model of the hydraulic actuation system is composed of the models of the hydraulic components and is experimentally validated by means of measurements that are obtained from a production pushbelt CVT. Several experiment types are considered. The correspondence between the measured and simulated responses is fairly good.

Power-Transfer Capacity of a Geared-Neutral Transmission

2007 ◽  
Author(s):  
Burak Gecim ◽  
Neil Anderson ◽  
Jeffrey Wehking
Keyword(s):  
Continuously Variable Transmission ◽  
Maximum Power ◽  
Contact Temperature ◽  
Design Parameters ◽  
Power Transfer ◽  
Power Capacity ◽  
Variable Transmission ◽  
Capacity Estimates ◽  
Ratio Range

Geared-neutral Continuously Variable Transmission (CVT) designs offer various kinematic advantages including a wide ratio range, and elimination of starting devices. However, they suffer from power re-circulation through the Continuously Variable Unit (CVU), which reduces the overall CVT efficiency and increases the CVU contact temperatures. This, in turn, limits the CVT power rating. In this study, the CVU and the CVT design parameters are optimized simultaneously to yield the highest power capacity. The CVU power capacity estimates are based on an instantaneous CVU-contact-temperature of 180°C. It is shown that a CVU design that yields the maximum power capacity is different from a design that yields the highest CVU efficiency.

The Research of Axial Deflection and Generatrix of Metal Belt CVT

2009 ◽  
Author(s):  
Wu Zhang ◽  
Kai Liu ◽  
Chun-Guo Zhou ◽  
Yi-Duo Wei ◽  
Ning-Qiang Wu
Keyword(s):  
Numerical Methods ◽  
Life Span ◽  
Continuously Variable Transmission ◽  
The State ◽  
Design Parameters ◽  
Actual Situation ◽  
Contact Strength ◽  
Working Process ◽  
Calculating Method ◽  
Variable Transmission

To reduce the metal belt’s axial deflection of the metal belt continuously variable transmission (CVT) during the working process, the value of the axial deflection has been calculated by using numerical methods. The precision of two methods to calculate the deflection has been compared. A calculating method closer to the actual situation has been attained. According to the principle of conjugate curves, and with the involute generatrix of the metal belt as example, a solution to the generatrix of the pulley conjugated with it is obtained, and the relation between the pullys generatrix curvature and the pulleys generatrix contact strength is achieved. By changing the metal belt value of the design parameters, the state subject to force between the pulley and the metal belt can be improved. So as to ensure the whole metal belt level transmit in the process of speed changes. Theoretically, the axial deflection can be eliminated completely, and the life span of the metal belt and the reliability of the transmission, as well as the performance of the metal belt CVT can be greatly improved, so as to provide the references for the CVT design.

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