Variable Gear Research Articles

Краткая теория зубчатого вариатора

Gear variator is a gear mechanism with the variable transfer ratio. Unsuccessful attempts of creation of a gear variator were undertaken repeatedly. The main problem – maintenance of constant gearing of cogwheels of a variator. The decision of this problem is based on use of a kinematic chain with two degrees of freedom. The gear variator in the form of the closed differential mechanism has definability and allows changing the transfer ratio in the set range. Thus external variable technological loading itself changes the transfer ratio. Adaptive to variable loading the gear variator works without the control mechanism. The gear variator opens essentially new concept of creation of adaptive techniques for machines with variable technological resistance (for example, adaptive gearboxes). The theory of a gear variator is based on a discovery “Effect of force adaptation in mechanics”, published in leading editions of world press. According to this discovery the kinematic chain with two degrees of freedom, containing the mobile closed contour, becomes the definable mechanism at presence only one input link. Such mechanism gets property independently to change speed of motion of a output link depending on variable loading. The discovery is based on mechanics laws. In work bases of the theory of a gear adaptive variator are stated.

Comparison of Two Designs of Differential Planetary Gear with Differential in Output

The goal of the presented contribution is a comparison of two variants of differential mechanical planetary gearboxes. The designed variants of differential gearboxes are characterized by gear shifting under load. Reflected depending on the variable gear may be a change of gear ratios, either stepped or continuously. The results of kinematic analyses of both variants of differential planetary gearbox with differential in output are shown in tabular and graphical form

Research on Power Matching of Automatic Variable Transmission

Automatic Variable Transmission (AVT) is composed of a metal belt CVT unit and a step speed changing transmission component. According to the needs of automotive conditions, AVT can realize continuously variable transmission and gear transmission, which not only play the advantage of gear transmission efficiency, but also overcome the deficiency of CVT when it is in high-speed. In the paper, the transmission matching rule is introduced, and engine model is established using engine test data. Based on SimulationX software, a vehicle that equips AVT is used for modeling and simulation. Finally the power matching is researched.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Experimental System and Creation of Virtual Guiding Surfaces)

We describe a new robotic assist device: the passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator. PASArms are physically passive. The force to manipulate the arm end must be provided by the operator. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces that constrain and guide the motion of the operator. PAS-Arms have three joints and a three dimensional workspace, but possess only two degrees of freedom due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. In this paper, we first discuss the manipulability ellipsoid for the PAS-Arm. The major axis of the ellipsoid is the direction in which the arm end may be easily manipulated, and vice versa. We have developed an experimental system for the PAS-Arm. The CVTs of the experimental system may not adjust the transmission ratio to zero. Second, we describe an algorithm to address that problem. Finally, we present initial experiments that verify the PAS-Arm mechanism. The experimental results successfully produced virtual guiding surfaces.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.76, No.763, pp. 611-618, 2010.

Variable gearing in a biologically inspired pneumatic actuator array

A fundamental feature of pennate muscles is that muscle fibers are oriented at an angle to the line of action and rotate as they shorten, becoming more oblique throughout a contraction. This change in fiber orientation (pennation angle) can amplify the shortening velocity of a fiber and increase output velocity of the muscle. The velocity advantage resulting from dynamic changes in pennation angle can be characterized as a gear ratio (muscle velocity/fiber velocity). A recent study has shown that a pennate muscle's gear ratio varies automatically depending on the load such that a muscle operates with a high gear during rapid contractions and low gear during forceful contractions. We examined whether this variable gearing behavior can be replicated in a pennate array of artificial muscles. We used McKibben type pneumatic actuators, which shorten in tension when filled with compressed gas. Similar to muscle fibers, the actuators expand radially during shortening, a feature thought to be a critical part of the variable gearing mechanism in pennate muscles. We arranged McKibben actuators in an array oriented to mimic a pennate muscle, and quantified the system's gear ratio during contraction against a range of loads. Video was used to measure the gear ratio during each contraction. We find that similar to pennate muscles, the gear ratio decreases significantly with increasing load and that variable gearing results from load-dependent variation in the amount of actuator rotation. These results support the idea that variable gearing in pennate muscles is mediated by difference is fiber rotation and the direction of muscle bulging. The behavior of our artificial muscle array also highlights the potential benefits of bio-inspired architectures in artificial muscle arrays, including the ability to vary force and speed automatically in response to variable loading conditions.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Design of Mechanism · CVT and Experimental System)

We describe a new robotic assist device: a passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator, handling a shared payload. PAS-Arms are physically passive. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces, which constrain and guide the motion of the payload within a shared workspace. PAS-Arms have three joints and a three-dimensional workspace, but possess only a two degrees of freedom, due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. We have developed an experimental system of the PAS-Arm. In this paper, we describe kinematic specification of the experimental system. We discuss the differential relation of transmission ratios created by the CVTs. We conducted the relationship between transmission ratio resolutions of the CVTs and resolutions of normal vector of the virtual guiding surface, and the relationship between angular velocities of PAS-Arm’s joints and time derivative of the transmission ratios. Assuming that the Euclidean norm of the angular velocities is constant, maximum time derivative of transmission ratios is in proportion to link lengths of the PAS-Arm. We also describe the design of the CVT for use in the experimental system.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.75, No.749, pp. 104-112, 2009.

BMW V8 Gasoline Engine With Turbocharging, Direct Injection and Fully Variable Valve Gear

BMW V8 Gasoline Engine With Turbocharging, Direct Injection and Fully Variable Valve Gear

2103 トランスミッションのギヤノイズばらつき予測法の開発(OS-06 歯車の振動・騒音)

2103 トランスミッションのギヤノイズばらつき予測法の開発(OS-06 歯車の振動・騒音)

Simulation Study on CMM Measuring Path Based on the CAD Models of Bevel Gear

As an important part in sliding-limiting differential, the variable ratio noncircular bevel gears can increase the locking factor of the bevel gear differential and improve the vehicles’ off-road capability in transit. At present, this differential has become a study hotspot that many researchers are working over because of its compact structure, cheap cost, good assembly and perdurable capability. In order to get the bevel gear’s processing accuracy, this paper introduced the generating process of the bevel gear’s CMM measuring path, probed the similarity in motion between spherical cutter’s CNC machining and CMM measuring, and then simulated and analyzed the bevel gear’s CMM measuring path by power mill in use of NC authentication method, which provided a reference for the choice of complex surfaces’ measuring methods.

Research on Mechanical Wind Machine of Constant Velocity

Primary technical parameters of centrifugal style speed controller were determined by Routh-Hurwitz criterion; the section gear variator could reach the standard of common gear driving of 9 grade precision indicators through design and calibration, especially suitable for low-rotate speed condition. The mechanical wind machine of constant velocity is novel in mode, briefness in structure, low in making cost and good for spreading and using.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Basic Concept and Mechanism)

We describe a new robotic assist device: a passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator, handling a shared payload. PAS-Arms are physically passive. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces, which constrain and guide the motion of the payload within a shared workspace. PAS-Arms have three joints and a three dimensional workspace, but possesses only a two degrees of freedom, due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. The combination of CVTs and differential gears places one mechanical constraint on three angular velocities of the joints. PAS-Arms have no joint actuators and no force sensors. Thus they are potentially well suited to safety and low cost. This paper proposes a basic concept of PAS-Arms and explains a principle and a construction of PAS-Arms. We discuss the relation of PAS-Arms to conventionally actuated robots and another type of assist arms. We also describe range of transmission ratio of CVTs.11. This paper is the full translation from the transactions of JSME, Series C, Vol.73, No.730, 2007.

Adaptive Drive of Manipulator Module

The production operation of the module includes stages: acceleration, breaking and the installed motion. Optimum on power and sizes the drive of the module of the manipulator should overcome the force matching a variable load at different stages of operation at constant power of an engine. For this purpose it is offered to use the adaptive mechanical drive containing the electric motor and an adaptive gear variator with constant engagement of toothed wheels. The adaptive gear variator provides the variable transfer ratio only owing to the mechanical properties lost-free energy on its transformation and without control means. The gear variator with constant engagement of toothed wheels is a planetary gear with two degrees of freedom, having the superimposed differential constraint under action of forces.

Analysis of Variable Gear System on Energy Consumption in Electric Vehicle Using Simulation Tool

Analysis of Variable Gear System on Energy Consumption in Electric Vehicle Using Simulation Tool

Structure Improvement on Dual Variable Gear Shaft of the Transmission for ZL50 Wheel Loader

Based on the CAE analysis. The dual variable gear shaft of the transmission for domestic ZL50 wheel loader was redesigned and the processing technology was optimized. The problem of the hardness of the spline which connects the dual variable gear shaft and the working hydraulic pump can not meet the requirements after heat treatment caused by unreasonable design was solved. The problem of the low geometric tolerance and early wear of the spline were solved. After practical application, the market feedback shows that the failure rate, service life and reliability greatly of new designed shaft were enhanced

Movement mechanics as a determinate of muscle structure, recruitment and coordination

During muscle contractions, the muscle fascicles may shorten at a rate different from the muscle-tendon unit, and the ratio of these velocities is its gearing. Appropriate gearing allows fascicles to reduce their shortening velocities and allows them to operate at effective shortening velocities across a range of movements. Gearing of the muscle fascicles within the muscle belly is the result of rotations of the fascicles and bulging of the belly. Variable gearing can also occur as a result of tendon length changes that can be caused by changes in the relative timing of muscle activity for different mechanical tasks. Recruitment patterns of slow and fast fibres are crucial for achieving optimal muscle performance, and coordination between muscles is related to whole limb performance. Poor coordination leads to inefficiencies and loss of power, and optimal coordination is required for high power outputs and high mechanical efficiencies from the limb. This paper summarizes key studies in these areas of neuromuscular mechanics and results from studies where we have tested these phenomena on a cycle ergometer are presented to highlight novel insights. The studies show how muscle structure and neural activation interact to generate smooth and effective motion of the body.

Novel Proposals for the Realization of Variable-Transmission Magnetic Gear

This paper presents different designs for the realization of a variable transmission magnetic gear (VTMG). The proposed designs utilize permanent magnets and copper coils. The basic concept is varying the gear ratio by pole changing. The FEM simulation results show that a VTMG can be realized and that the symmetry of the designs is vital for the correct operation of the VTMG. The VTMG is useful in variable speed/torque applications such as wind power generation, electric traction, power tools, and so on.

Optimal design in gear ratio of a city bike

This article examines the optimal gear ratios in speed shifting of a city bike. We first defined the environmental factors of the bike as slope and velocity, the product factor as gear ratio, the objective factors of the user as pedaling rate and heart rate, and the subjective factor of the user as comfort. We performed two experiments. The first experiment is the factor experiment, the usage range and characteristics of such factors of the city bike as slope, velocity, gear ratio, pedaling rate, heart rate, and gear change frequency are obtained from analysis of test results. The second experiment is the comfort experiment. Based on the results of the factor experiment, we set three levels for each factor of velocity, slope, and gear ratio to perform experiments. We examined and predicted variable relationships through analysis of variance and regression analysis of the results of the comfort experiment. The gear ratio range obtained in this study was 0.80–2.55, with a gear ratio variation of 319%; the optimal 6-speed gear ratios were 0.80, 1.00, 1.42, 1.53, 1.66, and 2.55. The experimental design, analysis methods, and evaluation results established by this study can be used as a reference for the development of new products and in related studies.

Identifying the origins of fishing gear ingested by seabirds: a novel multivariate approach

Abstract The global decline of albatrosses (Diomedidae: Procellariiformes) is thought to have occurred largely as a direct result of fishery‐related mortality. Albatrosses and other large petrels interact with fisheries in several ways, including scavenging used bait and discarded offal, which may contain hooks. Hooks that are ingested by breeding birds are often fed to chicks which subsequently regurgitate them shortly before fledging. In this study a series of mathematical (cladistic, cluster and principal components) analyses are applied to a sample of 241 items of fishing gear (hook, snood and hook/snood unit) collected from seabird nest sites on Bird Island, South Georgia, and 44 reference gear items provided by four South Atlantic regional fisheries. The five separate analyses failed to assign most gear to a particular fishery or to identify any consistent annual trends. The homogeneous nature of the material, which was largely derived from the same manufacturers, meant that gear origin could not be determined. This suggests that hooks found at seabird colonies in this, and potentially other regions, will be of limited use in identifying offending fisheries, unless operators are obliged to deploy gear with unique marks in the future. Nevertheless, it is suggested that this approach should work effectively where birds interact with a range of fisheries targeting different species using variable gear. This study therefore represents an innovative approach to the characterization of lost fishing gear with potentially widespread application. Copyright © 2010 John Wiley & Sons, Ltd.

Operation Mode Analysis and Parameters Design of a Novel Power Split Hybrid Transmission System

A new type of power split hybrid transmission system based on metal belt-type continuously variable transmission(CVT) and planetary gear is provided.Different operation modes of the new type of hybrid transmission system are analyzed.The parameters related to power source and powertrain are designed.The vehicle performance simulation model is built under the Matlab/Simulink environment,the acceleration performance under motor driving and engine-motor combined driving as well as fuel economy under UDDS and 10～15 cycle are simulated.The simulation results show that the acceleration time is only 9.65 s from 0 to 100 km/h,and fuel consumption is 4.32 and 3.74 L under UDDS and 10～15 cyclic condition respectively.

Variable gearing in pennate muscles.

Muscle fiber architecture, i.e., the physical arrangement of fibers within a muscle, is an important determinant of a muscle's mechanical function. In pennate muscles, fibers are oriented at an angle to the muscle's line of action and rotate as they shorten, becoming more oblique such that the fraction of force directed along the muscle's line of action decreases throughout a contraction. Fiber rotation decreases a muscle's output force but increases output velocity by allowing the muscle to function at a higher gear ratio (muscle velocity/fiber velocity). The magnitude of fiber rotation, and therefore gear ratio, depends on how the muscle changes shape in the dimensions orthogonal to the muscle's line of action. Here, we show that gear ratio is not fixed for a given muscle but decreases significantly with the force of contraction (P < 0.0001). We find that dynamic muscle-shape changes promote fiber rotation at low forces and resist fiber rotation at high forces. As a result, gearing varies automatically with the load, to favor velocity output during low-load contractions and force output for contractions against high loads. Therefore, muscle-shape changes act as an automatic transmission system allowing a pennate muscle to shift from a high gear during rapid contractions to low gear during forceful contractions. These results suggest that variable gearing in pennate muscles provides a mechanism to modulate muscle performance during mechanically diverse functions.