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Journal Article

Relation between the Weave Mode in Low Speed Range and Slalom Running of Motorcycles

Recently, our research has focused on the weave mode. This is a representative vibration mode of motorcycles and is important when considering maneuverability and stability. In a method of analyzing the weave mode, a disturbance is applied to the handle bars of the motorcycle during running and then the response waveform of the roll angle and other items at that time is used to perform estimations. However, when the motorcycle is driven at low speeds, the steering operations of the rider have a large effect on the running data and this makes estimation difficult. Therefore, it was assumed that weave mode data can be estimated from slalom running data since this possesses almost the same vibration frequency as the weave mode in low speed range. In this research, a simulation was used to investigate the relationship between the weave mode and slalom running.
Technical Paper

Light Body for Small Vehicles Using High-Quality Die-Casting Component

A high-quality die-casting technology has been developed for lightweight aluminum frame structures that produces high-strength aluminum parts that are also weldable. This new technology has been used in casting frames for motorcycles and snowmobiles and has enabled improved frame designs with far fewer component parts than was possible before. This die-casting technology also results in a significant reduction in energy consumption during the manufacturing process.
Technical Paper

Lifetime Prediction of a Crankpin using a Ball on Disk Type Rolling Contact Fatigue Life Testing

This paper describes an experimental method to predict the rolling contact fatigue life of a crankpin in a market vehicle engine. The fatigue life up to pitting was evaluated by two laboratory tests including a fatigue life measurement using a ball-on-disk test machine and a crankpin durability measurement by an engine bench test. The surface observation after the tests revealed that the surface dent triggers pitting in both tests. The Weibull plot of the percent failure vs. cycle to failure as a function of the contact stress was presented. In order to directly evaluate the effect of the contact stress on the lifetime, the lifetime values measured at L50 are plotted in the diagram showing the contact stress vs. cycle to failure. The obtained relation can predict the lifetime under the controlled condition in which the number of maximum torque points is countable.
Journal Article

Friction Measurement of Al-17%Si Monolithic Cylinder with using Newly Developed Floating Liner Device

The improvement of fuel consumption is the most important issue for engine manufactures from the viewpoint of energy and environment conservation. A piston-cylinder system plays an important role for the reduction of an engine friction. For the improvement of the frictional behavior of the piston-cylinder system, it is beneficial to observe and analyze the frictional waveforms during an engine operation. To meet the above-mentioned demand, frictional waveforms were measured with using the renewed floating liner device. In the newly developed floating liner device, an actual cylinder block itself was used as a test specimen. The measured single cylinder was an aluminum monolithic type made of hypereutectic Al-17%Si alloy using a high pressure die casting process. The combined piston was a light weight forged piston and a DLC coated piston ring was used. For the measurement, 110cc air cooled single cylinder engine was used.
Technical Paper

Drop Test Simulation Model for Motorcycles

The finite element method (FEM) is generally utilized to investigate the chassis strength of a motorcycle. However, it is difficult to determine the load conditions for FEM analysis of a drop test. Therefore, a method of drop test strength prediction at the basic design stage has been developed by combining stress analysis with vehicle dynamics analysis. A mathematical model and computer simulation system have been developed to predict the load conditions obtained by accelerations at several chassis locations. The model is constructed using flexible bodies (e.g., front fork and rear arm) as well as rigid bodies. The flexible front fork model was made by combining beam theory with substructural methods. Also, the model includes a front fork friction model which describes Coulomb's friction in slide bushings. If dynamic analysis is replaced by an equivalent static analysis, the force can be predicted from the acceleration data and the mass distribution.
Technical Paper

Development of Pollution-Free Rapid Plating System

It is in the plating process that the worst bottleneck occurs in plant automation. We, however, have succeeded in making our plating process free from pollution and compact, allowing us to install this system within a production line and consequently establish a continuous production line resulting in a decrease in plating cost to about 1/2 of the previous cost. We have achieved an excellent chrome plating speed of 60µ/min, by placing an anode relatively close to the part to be plated and by sending the plating solution into the space between the two by means of a pump. This provides a plating speed 100 times faster than with conventional methods, while improving the quality of the plating coat considerably. The system is optimum for functional platings, and can be used for the plating of shock absorber rods, engine valves, engine cylinders, etc.
Technical Paper

Development of Fracture Splitting Method for Case Hardened Connecting Rods

The fracture splitting (FS) method for case hardened connecting rods has been developed to improve engine performance while decreasing production costs. The FS method is widely used for automotive connecting rods because it effectively improves their productivity. Normalized forging steels, microalloyed forging steels and powder metals have generally been used as the material in the FS method as they are easily split due to their brittleness. On the other hand, the materials to be used for high performance motorcycles are case hardened low carbon steels because they allow the connecting rods to be lightweight due to their high fatigue strengths. These materials, which have a hardened area of approx. 0.5mm in depth from the surface, have a ductile texture inside. This texture obstructs the crack propagation and makes the split force too high to split without deforming the bearing area.
Technical Paper

An Experimental Study of Connecting Rod Big Ends

Connecting rod design factors, such as geometric shape, capscrew torque and materials can significantly affect bore distortion and assembly stress. In this paper, experiments using different materials were conducted on several connecting rod big-ends with various shapes, bosses and bolts. The results show that the distortion of the big-end bore and the bolt stress are influenced considerably by the big-end shape, the bolt axial tension and the material under inertia force. It was also observed that the bolt bending stress and the load separating the big-end joint surface could be calculated with high accuracy using three-dimensional FEM in the initial connecting rod design.