• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.3
• /
• pp.269-275
• /
• 2009

This paper represents a study on the conceptual design of new automatic bicycle transmission. The gear change in a commercial bicycle is carried out by moving the chain between sprockets. By the use of a multiple sprocket for speed change the power loss and transmission shock may occur. To solve the problem of bicycle transmission, the improved solution was derived by the technical contradiction matrix of TRIZ. The conceptual solution is one sprocket which replaces the function of multiple sprockets and adapts actively to the pitch of chain. And it was confirmed to be an adequate design through the Independence Axiom of design axiom.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1022-1027
• /
• 2008

This paper represents a study on the conceptual design of new automatic bicycle transmission. The gear change in a commercial bicycle is carried out by moving the chain between sprockets. By the use of a multiple sprocket for speed change the power loss and transmission shock may occur. To solve the problem of bicycle transmission, the improved solution was derived by the technical contradiction matrix of TRIZ. The conceptual solution is one sprocket which replaces the function of multiple sprockets and adapts actively to the pitch of chain. And it was confirmed to be an adequate design through the Independence Axiom of design axiom.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.25 no.2
• /
• pp.133-139
• /
• 2017

The timing chain system, which is a typical power transmission technology applied to a vehicle, has been widely used by the automotive industry because it is normally designed to last a car's lifetime. However, the timing chain system may cause some problems due to the shape of the chains and the polygonal behavior on contact between the chain and the sprocket. In addition, noise and vibration caused by transmission error are the most typical problems encountered by major automotive manufacturers and they are considered as the main source of customer complaint. The initial tension of the chain-sprocket system is thought to be the main cause of transmission error, and it is regarded as the source of engine vibration and noise. The initial tension of the chain system should be controlled carefully since a low initial tension can cause twisting, which may lead to a system malfunction, while a high initial tension can reduce the service life due to a worn down contact surface. In this paper, the kinematic analysis model is generated with various initial tensions, which are controlled by changing the shape of the fixed guide with the largest contact surface with chain. The results showed that the transmission error was minimized on a particular range of initial tension, and the tendency showed that the error changed with a higher sensitivity at a lower initial tension.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.205-215
• /
• 2001

In this study, modeling and analysis procedure for the dynamic analysis of a high mobility tracked vehicle system were studied. The vehicle model used in this investigation is assumed to be consist of two kinematically decoupled subsystems. The chassis subsystem consists of chassis frame, sprocket, support rollers, road wheels, idler wheel, road wheel arms and idle wheel arm, while the track subsystem is represented as a closed kinematic chain consisting of track links and end connectors interconnected by revolute joints with bushing. Nonlinear contact force module describing the interaction between track link, and sprocket, idler wheel, road wheel, support roller, ground was used. The effects of road wheel arms and idler wheel arm due to tension adjuster are also considered.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.144-147
• /
• 2001

The planar tracked vehicle model used in this investigation consists of two kinematically decoupled subsystem, i.e., the chassis subsystem and the track subsystem. The chassis subsystem include the chassis frame, sprocket, idler and rollers, while the track subsystem is represented as a closed kinematic chain consisting of rigid links interconnected by revolute joints, In this paper, the recursive kinematic and dynamic formulation of the tracked vehicle is used to find the vertical forces and the distances of the certain track moved in the driving direction along the track. These distances and vertical forces obtained are used to calculate the sinkage of a terrain. The FEM is adopted to analyze the interaction between the tracked vehicle and terrain. The terrain is represented by a system of elements with specified constitutive relationships and considered as a piecewise linear elastic, plastic and isotropic material. When the tracked vehicle is moving with different speeds on the terrain, the elastic and plastic deformations and the maximum sinkage for the four different types of a isotropic soil are simulated.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.11
• /
• pp.919-925
• /
• 2016

In this study, multibody dynamic and mechanical analyses were conducted for the structure of roller chain bucket elevator system. The fatigue life of the roller chain elevator system was determined under static and fatigue loadings. Results of multibody dynamic analysis suggested that the maximum contact force occurred at the drive sprocket engagement point with the roller chain due to maximum tension. Fatigue analysis results suggest that the high load roller chain system is durable and safe because its life time is more than 700,000 cycles, close to its designed value (1,000,000 cycle). However, the contact portion of plate and pin needed a safety factor. The dynamic analysis of the heavy load roller chain was conducted with a multibody dynamic analysis program. The results obtained in this study can be utilized for dynamic analysis of roller chain systems in all industries.

• Journal of Applied Reliability
• /
• v.9 no.1
• /
• pp.29-35
• /
• 2009

Due to the excellent durability of Timing Chain, it has been widely used for vehicle engine system. Unlike the timing belt, since the timing chain is operated with the metallic sprocket, the lubrication system is absolutely needed to get this system start. As frequently met at the field, the lubricant has a strong tendency to leak out from the engine due to its severe operating environment. In this paper, results of investigation for thermal movement of aluminum chain cover were described to maximize the sealing ability which is desperately needed at the development stage of engine. Based on these results, some ideas for reproducing the leakage phenomenon and solving methods were proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.329.2-329
• /
• 2002

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash of gearbox as well as sag of driving chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. (omitted)

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.6
• /
• pp.111-121
• /
• 2015

The objective of this study is to develop an automatic object changer unit to improve changing process problems existing in the conventional horizontal machining center. In order to perform this objective, an upward and downward traverse unit was designed. This unit consists of a motor, reducer, chain and sprocket wheel, and an upper and lower base. This automatic object changer unit performs a sliding contact motion in a purpose built and designed frame. Constraint conditions for the upward and downward traverse unit were first designed. Then, an operation mechanism was designed and introduced as the sum of the kinetic energy for the sprocket wheel and the upper and lower base and which was based on the moment of inertia, which is the kinetic energy of the converted upward and downward traverse unit in the side of the reducer. The paper covers the design of th e Automatic Pallet Changer for th e machining center.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.2
• /
• pp.140-150
• /
• 2002

The planar tracked vehicle model used in this investigation consists of two kinematically decoupled subsystems, i.e., the chassis subsystem and the track subsystem. The chassis subsystem includes the chassis frame, sprocket, idler and rollers, while the track subsystem is represented as a closed kinematic chain consisting of rigid links interconnected by revolute joints. In this study, the recursive kinematic and dynamic formulation of the tracked vehicle is used to find the vertical terce and the distance of an arbitrary track moved in the driving direction along the track. These distances and vertical forces obtained are used to get the deformation and sinkage of a terrain. The FEM(Finite Element Method) is adopted to analyze the interaction between tracked vehicle and terrain. The terrain is represented by a system of elements wish specified constitutive relationships and considered as a piecewise linear elastic, plastic and isotropic material. When the tracked vehicle is moving with different speeds on the terrain, the elastic and plastic deformations and the maximum sinkage for the four different types of isotropic soils are simulated.