Design of a gear shifting system for bicycles

A gearing system is the mechanism used, by different types of transports, to modify the features of the transmission. This mechanism must adapt the speed, and torque, according to the road conditions and the requirements of the driver, in order to optimise the driving. In case of bicycles, the transmission mechanism adapts the energy produced by the muscular effort of the driver into rotational movement of the wheels. Nowadays, most of them include a derailleur gearing system, which uses a chain transmission and several chain rings to modify the speed ratio transmitted to the rear wheel. However, since the different context of use, and users, require different types of bicycles, the market also includes a large variety of designs and gearing proposals. The main goal of this project is to develop a design proposal based on a gear shifting system. From previous research, with focus on the state of the art and the actual market of bicycles, different ideas of designs arise. As objective, the proposals obtained must accomplish a functional improvement in relation to precedent models and the integration of the different systems studied during the research. Then, these are studied to verify the technical possibilities to carry out each one of them. The proposal finally selected is a redesign of the shifting system of the Sturmey-Archer gearing hub, which is known to be one of the first internal gearing systems. This mechanism was very popular when was launched but it presented problems in the cable shifting system, which failed in activating the correct speed. As a solution, the design focuses on incorporating the ratchet system of a motorcycle to replace the direct cable shifting. During the design process, the parts and the assembly are modelled by 3D software, and evaluated by mechanical calculations and simulations, which must guarantee the correct performance of the mechanism. In this process, the materials used are also compared and selected to achieve the safety condition. To conclude, the development of this project is considered to have followed correctly the process stablished. The results of the different design stages are satisfactory. Regarding the resulting proposal, it is considered to achieve the safety and functional goals, although some aspect might be modified to obtain a more complete solution

The Design and Prototype Manufacture of a Planetary Gear Reducer

The gear reducer of the power system can be ordinary spur gear reducer, worm and worm gear reducer, or planetary gear reducer. Due to the compact size, light weight, and multi-degrees of freedom; planetary gear reducers are commonly used in various transmissions. One of its applications is used as the gear reducer for industrial purpose. The reduction ratios of 1-stage planetary gear reducers are limited to 3 ~ 10. This paper focused on the design and prototype manufacture of a 1-stage planetary gear reducer. First, according to the concept of train value equation, the planetary gear reducer with reduction ratio 4 is proposed. Based on the involute theorem, the gear data of the planetary gear reducer are obtained. Finally, based on the results of kinematic design and meshing efficiency analysis, the integrated design of the planetary gear reducer was carried out and the prototype was manufactured to verify the design theorem. The results of this paper can be used as a reference for engineers to design the gear reducers for industrial purpose

Research of the problem of optimization and development of a calculation method for two-stage chain drives used in heavy industrial vehicles in conditions of economic efficiency

The article is dedicated to the problem of optimization of chain drives of the drilling unit. At present, increasing the power per machine to the optimal limits, reducing the material and energy consumption per unit capacity of the machine, as well as operating costs are considered topical issues. The machines that are designed and constructed to optimal limits must be very powerful and productive. The machines that are applied to perform drilling works in the oil and gas industry must be easy to operate, reliable and have ability to operate for a long time. When constructing such machines, their being lightweight, economical, as well as their preparation in a short time and at low cost should be taken into account in advance. In order to ensure the reliable operation of drilling rigs, it is more expedient to apply chain drive in their mechanical transmission. First of all, the application of chain drive in drilling units and hoisting mechanisms is considered. Then a calculation method was developed for the chain drives of the drilling unit used in deep exploration wells and the exploitation of wells, and, accordingly, the calculation of the chain drive was carried out. The chain drive consists of drive and driven sprockets and a chain that encompasses the sprockets and engages in their teeth. Chain drives with several driven sprockets are also used. In addition to the basic listed elements, chain drives include tensioners, lubricating device and guards. The chain consists of hinged links that provide mobility or “flexibility” of the chain. Chain drives can be performed in a wide range of parameters. The calculation took into account the quality of the material, the service life and durability of the chain drive constructio

Application of traction drives as servo mechanisms

The suitability of traction drives for a wide class of aerospace control mechanisms is examined. Potential applications include antenna or solar array drive positioners, robotic joints, control moment gyro (CMG) actuators and propeller pitch change mechanisms. In these and similar applications the zero backlash, high torsional stiffness, low hysteresis and torque ripple characteristics of traction drives are of particular interest, as is the ability to run without liquid lubrication in certain cases. Wear and fatigue considerations for wet and dry operation are examined along with the tribological performance of several promising self lubricating polymers for traction contracts. The speed regulation capabilities of variable ratio traction drives are reviewed. A torsional stiffness analysis described suggests that traction contacts are relatively stiff compared to gears and are significantly stiffer than the other structural elements in the prototype CMG traction drive analyzed. Discussion is also given of an advanced turboprop propeller pitch change mechanism that incorporates a traction drive

Angular Velocity Analysis of an Epicyclic Gear Train Using Fundamental Circuits and a Block Diagram

The prediction of angular velocity is a prerequisite to investigate the power flow and mechanical efficiency of an epicyclic gear train. This paper presents a useful tool, which combines the fundamental circuit and a block diagram, to analyze the angular velocity of an epicyclic gear train. It is a visualized and straightforward method without manipulating tedious kinematic equations, which makes the angular velocity analysis of epicyclic gear trains more simplified. A compound epicyclic gear train used in a synchronous differential device is taken as an example to demonstrate the analysis process of the proposed approach. The velocity ratio of the epicyclic gear train is also derived

Design and Analysis of a Novel Speed-Changing Wheel Hub with an Integrated Electric Motor for Electric Bicycles

The aim of this paper is to present an innovative electromechanical device which integrates a brushless DC (BLDC) hub motor with a speed-changing wheel hub stored on the rear wheel of an electric bicycle. It combines a power source and a speed-changing mechanism to simultaneously provide functions of power generation and transmission for electric bicycles. As part of the proposed integrated device, the wheel hub consists of a basic planetary gear train providing three forward speeds including a low-speed gear, a direct drive, and a high-speed gear. Each gear is manually controlled by the shift control sleeve to selectively engage or disengage four pawl-and-ratchet clutches based on its clutching sequence table. The number of gear teeth of each gear element of the wheel hub is synthesized. The BLDC hub motor is an exterior-rotor-type permanent-magnet synchronous motor. Two-dimensional finite-element analysis (FEA) software is employed to facilitate the motor design and performance analysis. An analysis of the power transmission path at each gear is provided to verify the validity of the proposed design. The results of this work are beneficial to the embodiment, design, and development of novel electromechanical devices for the power and transmission systems of electric bicycles

Compendium in Vehicle Motion Engineering

This compendium is written for the course “MMF062 Vehicle Motion Engineering” at Chalmers University of Technology. The compendium covers more than included in that course; both in terms of subsystem designs and in terms of some teasers for more advanced studies of vehicle dynamics. Therefore, it is also useful for the more advanced courses, such as “TME102 Vehicle Modelling and Control”.The overall objective of the compendium is to educate engineers that understand and can contribute to development of good motion and energy functionality of vehicles. The compendium focuses on road vehicles, primarily passenger cars and commercial vehicles. Smaller road vehicles, such as bicycles and single-person cars, are only very briefly addressed. It can be mentioned that there exist a lot of ground-vehicle types not covered at all, such as: off-road/construction vehicles, tracked vehicles, horse wagons, hovercrafts, and railway vehicles.Functions are needed for requirement setting, design and verification. The overall order within the compendium is that models/methods/tools needed to understand each function are placed before the functions. Chapters 3-5 describes (complete vehicle) “functions”, organised after vehicle motion directions:\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 3:\ua0Longitudinal\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 4:\ua0Lateral\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 5:\ua0Vertical\ua0dynamicsChapter 1 introduces automotive industry and the overall way of working there and defines required pre-knowledge from “product-generic” engineering, e.g. modelling of dynamic systems.Chapter 2 also describes the subsystems relevant for vehicle dynamics:• Wheels and Tyre\ua0• Suspension\ua0• Propulsion\ua0• Braking System\ua0• Steering System\ua0• Environment Sensing SystemThe compendium is released in a new version each year, around October, which is the version your read now. A "latest draft" is more frequently updated and often includes some more, sometimes unfinished, material: https://chalmersuniversity.box.com/s/6igaen1ugcjzuhjziuon08axxiy817f

Compendium in Vehicle Motion Engineering

This compendium is written for the course “MMF062 Vehicle Motion Engineering” at Chalmers University of Technology. The compendium covers more than included in that course; both in terms of subsystem designs and in terms of some teasers for more advanced studies of vehicle dynamics. Therefore, it is also useful for the more advanced course “TME102 Vehicle Modelling and Control”.The overall objective of the compendium is to educate vehicle dynamists, i.e., engineers that understand and can contribute to development of good motion and energy functionality of vehicles. The compendium focuses on road vehicles, primarily passenger cars and commercial vehicles. Smaller road vehicles, such as bicycles and single-person cars, are only very briefly addressed. It should be mentioned that there exist a lot of ground-vehicle types not covered at all, such as: off-road/construction vehicles, tracked vehicles, horse wagons, hovercrafts, or railway vehicles.Functions are needed for requirement setting, design and verification. The overall order within the compendium is that models/methods/tools needed to understand each function are placed before the functions. Chapters 3-5 describes (complete vehicle) “functions”, organised after vehicle motion directions:\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 3:\ua0Longitudinal\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 4:\ua0Lateral\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 5:\ua0Vertical\ua0dynamicsChapter 1 introduces automotive industry and the overall way of working there and defines required pre-knowledge from “product-generic” engineering, e.g. modelling of dynamic systems.Chapter 2 also describes the subsystems relevant for vehicle dynamics:• Wheels and Tyre\ua0• Suspension\ua0• Propulsion\ua0• Braking System\ua0• Steering System\ua0• Environment Sensing Syste