Study of a Non-Circular Gear Infinitely Variable Transmission

2014 ◽  
Author(s):  
Kumar Hebbale ◽  
Dongxu Li ◽  
Jing Zhou ◽  
Chengwu Duan ◽  
Chi-Kuan Kao ◽  
...  
Keyword(s):  
Static Analysis ◽  
Fuel Efficiency ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Development Effort ◽  
Function Generator ◽  
Multiple Function ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Function Generators

Improving automobile fuel efficiency is an important research and development effort in the automotive industry. In the transmission area, it is generally understood that optimum fuel economy can be achieved via a combination of highly efficient power transfer (gears, for example) and an ability to transmit power at an infinite number of ratios (CVT, for example). In this paper, a geared infinitely variable transmission (IVT) is analyzed for efficiency through static analysis. This IVT is based on a non-circular gear concept described in [1, 2]. This IVT consists of multiple function generators with each function generator comprising two sets of non-circular gear sets whose outputs are combined with a summing planetary gear set. Each function generator provides the desired gear ratio for only a part of the driving rotation. So, multiple function generators are combined along with multiple one-way clutches to provide an infinitely variable transmission. This paper first explains the operating principle of the geared IVT. A static analysis of the IVT powerflow is derived and it is shown that this powerflow exhibits a torque recirculation phenomenon, which is not desired. This recirculation phenomenon is expected to be present in all similarly arranged IVTs where two inputs are combined using a planetary gear set to provide infinite gear ratio capability. The efficiency of the IVT is calculated based on assumed individual component efficiency and it is shown that, owing to torque recirculation, the efficiency of this transmission may not compare well with that of current automatic transmissions for a passenger car application.

Development of 2 Stage CVT Shift Control Algorithm to Reduce Torque Variation During 1-2 Upshift of Planetary Gear

2012 ◽  
Author(s):  
Jeongman Park ◽  
Sunghyun Ahn ◽  
Oheun Kwon ◽  
Youngho Jun ◽  
Minhyo Kim ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Shift Quality ◽  
Response Characteristics ◽  
Shift Control ◽  
Variable Transmission ◽  
Vehicle Simulator ◽  
Simulation Results ◽  
Fuzzy Control Algorithm

In this paper, a 2 stage continuously variable transmission (CVT) shift control algorithm is proposed for the 1–2 upshift of the planetary gear to achieve the shift quality. A fuzzy control algorithm is designed considering the relatively slower response characteristics of CVT. In order to evaluate the performance of the control algorithm, a 2 stage CVT vehicle simulator is developed including a dynamic model of the CVT powertrain. From the simulation results, it is found that CVT gear ratio changes faster in the inertia phase and remains constant after the inertia phase of the planetary gear shift, which provides the reduced torque variation by the proposed control algorithm.

Design of a Series-Type Independently Controllable Transmission Mechanism

2012 ◽  
Author(s):  
Guan-Shyong Hwang ◽  
Der-Min Tsay ◽  
Jao-Hwa Kuang ◽  
Tzuen-Lih Chern ◽  
Tsu-Chi Kuo
Keyword(s):  
Angular Velocity ◽  
Planetary Gear ◽  
Transmission Mechanism ◽  
Alternative Form ◽  
Input Shaft ◽  
Planetary Gear Trains ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Gear Trains ◽  
Series Type

This study proposes a design of transmission mechanism which is referred to as a series-type independently controllable transmission (ICT). The series-type ICT is an alternative form of the parallel-types proposed in the former researches. The series-type ICT can serve as a continuously or an infinitely variable transmission mechanism, and it can also produce a required angular output velocity that can be independently manipulated by a controller and not affected by the angular velocity of the input shaft. The series-type ICT mechanism is composed of two planetary gear trains and two transmission-connecting members. Kinematic and dynamic characteristics of the ICT mechanism are analyzed and their analytical equations are derived for application in this study.

A Positively-Engaged Infinitely Variable Transmission Using Split Helical Gears

2018 ◽  
Author(s):  
Ethan R. Brush ◽  
Carl A. Nelson
Keyword(s):  
Angular Velocity ◽  
Electric Vehicles ◽  
Gear Ratio ◽  
Helical Gears ◽  
Continuously Variable Transmissions ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
New Type ◽  
Working Principle

Continuously variable transmissions (CVTs), and the subset known as infinitely variable transmissions (IVTs) with gear ratio ranges reaching zero (0:1 or 1:∞ or “geared neutral”), offer motors the ability to run in preferred angular velocity ranges independent of transmission output speed, allowing optimization for power, torque, and efficiency. This paper presents and analyzes a positively engaged IVT (PE-IVT) mechanism of an entirely new type and working principle which solves the problems of current CVTs and is applicable to the unique requirements of robots, electric vehicles (EVs), and hybridelectric vehicles (HEVs).

scholarly journals Infinitely variable transmission with orbital pulleys

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988371
Author(s):  
Hector Cervantes-Culebro ◽  
Carlos Alberto Cruz-Villar ◽  
Orlando Palma-Marrufo
Keyword(s):  
Dynamic Model ◽  
Planetary Gear ◽  
The Other ◽  
Parallel Transmission ◽  
Translational Movement ◽  
Proposed Model ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Fixed Constant ◽  
Orbital Pulley

The purpose of this article is to propose an infinite variable transmission with orbital pulleys, which consists of two parallel transmission systems. The system comprises a planetary gear set and a continuously variable transmission. The principle of operation of the infinite variable transmission proposed in this article is based on the actuation of one half-sided pulley, which has a translational movement in a direction, and the same amount of movement is reproduced by the other half-sided orbital pulley in reverse to secure that the length of the belt remains constant. The fixed constant horizon enables the infinite variable transmission to change the transmission ratio from negative values to positive passing through zero in a continuous manner without using a clutch or interrupting the system. The dynamic model and prototype of the infinite variable transmission with orbital pulleys are developed for designing, controlling, and validating purposes. The model is obtained using the Euler–Lagrange methodology, and it is experimentally validated by comparing the proposed model with the experimental measures. The infinite variable transmission with orbital pulleys is controlled under different conditions; the experimental results show that the proposed design of infinite variable transmission provides robustness to maintain constant speeds at the output to changes at the input velocity.

MG-IVT: An Infinitely Variable Transmission With Optimal Power Flows

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Francesco Bottiglione ◽  
Giacomo Mantriota
Keyword(s):  
Planetary Gear ◽  
Operating Conditions ◽  
Gear Train ◽  
Transmission Ratio ◽  
Kinetic Characteristics ◽  
Optimal Power ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Zero Values ◽  
Optimal Efficiency

The infinitely variable transmissions (IVTs) allow the transmission ratio to vary with continuity, offering the possibility of also reaching zero values for the transmission ratio and the motion inversion. In this paper an original infinitely variable transmission system is described (MG-IVT). MG-IVT is made up of the coupling of a continuously variable transmission, a planetary gear train, and two ordinary transmissions with a constant transmission ratio. By means of two frontal clutches, the MG-IVT is allowed to get two different configurations. The main purpose is to get the configurations that make the optimal efficiency of the transmission at different transmission ratios. Kinetic characteristics of single component devices are obtained, and the MG-IVT system’s performance is determined by considering how the efficiency of the component devices change as a function of operating conditions. The advantages of the MG-IVT are therefore shown in terms of power and efficiency in comparison to the traditional IVT.

Design, Modeling, and Experimental Validation of a Novel Infinitely Variable Transmission Based on Scotch Yoke Systems

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
X. F. Wang ◽  
W. D. Zhu
Keyword(s):  
Planetary Gear ◽  
Speed Ratio ◽  
Control Module ◽  
Kinematic Behavior ◽  
Input Control ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Planetary Gear Sets ◽  
Noncircular Gears ◽  
Crank Length

A novel infinitely variable transmission (IVT) based on scotch yoke systems is designed to provide a continuously varied output-to-input speed ratio from zero to a specified value. By changing the crank length of scotch yoke systems, the speed ratio of the IVT can be continuously adjusted. The IVT consists of a pair of noncircular gears and two modules: an input-control module and a motion conversion module. The input-control module employs two planetary gear sets to combine the input speed of the IVT with the control speed from the stepper motor that changes the crank length of scotch yoke systems. The motion conversion module employs two scotch yoke systems to convert the combined speeds from the input-control module to translational speeds of yokes, and the translational speeds are converted to output speeds through rack–pinions. The speed ratio between the output of the motion conversion module and the input of the input-control module has a shape of a sinusoidal-like wave, which generates instantaneous variations. Use of scotch yoke systems provides a benefit to isolate the interaction between the crank length and the shape of the speed ratio, and a pair of noncircular gears can be used to eliminate the instantaneous variations of the speed ratio for all crank lengths. A prototype of the IVT was built and instrumented, and its kinematic behavior was experimentally validated. A driving test was conducted to examine the performance of the IVT.

Design, Modeling, and Simulation of a Geared Infinitely Variable Transmission

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
X. F. Wang ◽  
W. D. Zhu
Keyword(s):  
Planetary Gear ◽  
Speed Ratio ◽  
Start Up ◽  
Continuous Output ◽  
Direction Control ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Planetary Gear Sets ◽  
Working Principle ◽  
Crank Length

An infinitely variable transmission (IVT) to provide a continuous output-to-input speed ratio from zero to a certain value is designed, and its working principle is illustrated. It is a geared IVT (GIVT), since its function to achieve the continuously varied speed ratio is implemented by gears. Crank-slider systems are used in the GIVT; the output-to-input speed ratio is changed with the crank length. Racks and pinions, whose motion is controlled by planetary gear sets, are used to change the crank length when the cranks rotate. One-way bearings are used to rectify output speeds from different crank-slider systems to obtain the output speed of the GIVT. Since the crank-slider systems can introduce variations of the instantaneous speed ratio, a pair of noncircular gears is designed to minimize the variations. A direction control system is also designed for the GIVT using planetary gear sets. Finally, a vehicle start-up simulation and a wind turbine simulation to maintain a constant generator speed are developed based on a GIVT module in the Matlab Simulink environment.

Design and Analysis of a Novel Power-Split Infinitely Variable Power Transmission System

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Ender İnce ◽  
Mehmet A. Güler
Keyword(s):  
Power Flow ◽  
Power Transmission ◽  
Mechanical Efficiency ◽  
Flow Equations ◽  
Power Split ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Variable Power ◽  
New System ◽  
Agricultural Machines

In the last few decades, power-split infinitely variable transmission (IVT) systems have attracted considerable attention as they ensure high driving comfort with high total efficiencies, especially in off-highway vehicles and agricultural machines. In this study, a novel power-split-input-coupled IVT system is developed. The effects of various dynamic parameters such as power flow and Willis transmission ratio on the mechanical efficiency of the systems are investigated. Kinematic analysis of the new system has been carried out. In addition power flow equations are derived as functions of the power that flows through the infinitely variable unit (IVU). The results indicate that the main parameters, which are strictly related to mechanical efficiency are the power and torque flows through the IVU.

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