TECHNOLOGY

The crankshaft of the automobile has changed significantly in structure from its original simple form to today's highly complicated version in order to improve the efficiency of engine operation. As a core element of the engine, its strength must tolerate the distortions and pressures of engine function. The following is a description of the process of forging a crankshaft showing how its design and the method of forging have changed over time to improve form and durability.

PROCESS

After an hour in the forging process, a piece of steel is formed into the complex shape of a crankshaft. The important production points are : to manufacture the crankshaft with the least possible material, work and energy, and to absolutely exact dimension in order to minimize machining time.

ACCURACY

Many factors affect the accuracy of the final forged product : uneven temperatures during the forging process, precise dimensions of tools and dies, and deformity during knockout, flash trimming, twisting and heat-treating. All have to be addressed successfully to produce a high quality product. For example, in order to reduce machining allowance and obtain optimum balance of crankshaft, the forming process must be absolutely accurate. After all, the shorter and more simplified the machining time is, the lower the energy usage

MATERIAL

High quality specialty steel is used to manufacture the forged part to obtain both the required strength and a simplified machining process. In order to comply with accepted industry standards, specialty steels must be of high grades, processed with less energy, lower cost and reduced adverse ecological consequences. Steel producers constantly strive to research and develop increasingly higher quality steels.

FORMING

The steering knuckle is important for safety, maneuverability and driving comfort. A complex component, it requires the ultimate in extrusion, bending, punching and elongation forming technologies.

MATERIAL AND ENERGY SAVING

New technologies are essential to continue to raise production yields to reduce costs and minimize materials and energy use. Dedication to research and development has stimulated multiple advances in materials, dies, lubricants and forging facilities. The accumulation of this modernization is apparent today in new innovative forging methods developed to obtain the highest possible production yields, such as core forgings (double action flash-less forgings) and the ring rolling mill.

RESEARCH & DEVELOPMENT

"Net-shape" technology continues to improve in the areas of cold-forging, hot-cold complex and core forging. The "Net-shape" method, which eliminates the need for machining the main section of the forged component, results mainly from advanced development in production facilities, in die design and manufacture, and improvements in lubrication. Application of the "Net-shape" method greatly enhances environmentally friendly production.

PRODUCTIVITY

Consistent with the extraordinary growth of automobile production since the 1960's, the demand for forged parts has increased enormously. Impelled by technological advances in production facilities, die design, lubrication and cooling systems, productivity has risen to provide the auto industry with record volumes of extremely high quality, economically priced forged products.

BLACKSMITHS IN OHNO AREA

They say the Ohno Blacksmiths were the craftmen who came from Shiga Prefecture in the 12th century. They lived in Ohno Area ; the southern part of Chita City and the northern part of Tokoname City. They produced ABUMI (stirrup) and TSUBA (Sword-guide) in old days and afterwards changed to the making of agricultural tools.
In the Edo Period, the number of Ohno Blacksmiths increased most and reached to 185. The distinctive point was that they traveled for working and were called "DEKAJI (going-out blacksmith)". Their trip area were MIKAWA (around Toyota City), MINO (around Nakatsugawa City) and SHINSHU for manufacturing and fixing of farming forks and hoes. When they visited those area, they made tools by adjusting the angles between blade and handle or its shape of blade edge because the farming tools must fit the local farmer's usage and fit the soil condition.

MASTER TECHNIQUES AND TRADITIONS

Besides the people who made agricultural tools, there lived the blacksmiths for making the nails of wooden ships FUNAKAJI (Ship-nail maker) and KOMONOKAJI (Small iron-parts maker). They made various products ranging from nails to iron tweezers.
Ohno Blacksmiths had their own seasonal traditions. Every year, on the 2nd of January, they fixed a piece of sword-like plate on the pole or the beam. They prayed for their safety and prosperity of the new year in front of it. On the 8th of November, they held meeting called KANAYAMAKO to celebrate Japanese God of metalworking, KANAYAMAHIKO.

MANUFACTURING TOOLS

They were used to be called the professional blacksmith when they could make and use their own tools for themselves to work. In fact, each of them made various kinds of fire tongs. In old days, two persons of YOKOZA (Master) and SAKITE (Apprentice) worked together. Later, the Belt-Hammer was introduced and they adopted one person work.
They had also a variety of manufacturing tools－anvils, hammers, tongs, etc. Anvil was one of the most important tools. On New Year's Day, a set of KAGAMI-MOCHI (Rice-cakes) was decorated on it. They offered a prayer before it for safety.

MANUFACTURING SKILL

One of their products is BICCHU, a farmer's fork. BICCHU was made by their unique manufacturing technique and it had two kinds of methods. The blades of BICCHU and hoes, after a long use, got exhausted and wore down. Then, Ohno blacksmith fixed the exhausted edge by their unique remedy called SAKIGAKE method.
A sample of SAKIGAKE method is shown here. First, they connect a low carbon steel bar with the old edge and arrange its length. Then, they connect a high carbon steel plate on it and grind the edge. Finally, they quench the edge to finish.

A BLACKSMITH STUDIO

Ohno Blacksmiths were very enthusiastic people for creating tools and making things. Please enjoy looking at the Diorama of Ohno Blacksmiths.