| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
The new method of the tooth surface improvement in order to manufacture a high quality gear is developed when a shot peening process and a barreling process are continuously applied to tooth surfaces of a hardened and ground gear or a sheaved and hardened gear. The compressive residual stress induced on/below the gear tooth surface by the shot peening process increases the bending fatigue strength of the tooth root and the improvement of the surface roughness by the barreling process increases the surface durability (resistance for pitting, scoring and wear, etc.).
In this study, the hybrid apparatus for finishing the ground tooth surface is designed and manufactured. This apparatus is a prototype one in order to investigate a performance of the tooth surface improvement. However, by some modification of design, one can easily design the apparatus established in a gear manufacturing process line for an automobile transmission, in which the processes of shot peening and barreling are con
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ducted at the same time, and many gears are barreled together. The cost will scantly increase by an addition of the processes of shot peening and barreling.
Furthermore, a running test of high quality gears was conducted investigating the tooth profile, the surface roughness and the condition of the oil film formed between meshing gears. The processes of shot peening and barreling don't only restrict the gear with an involute curve, but also can be applied to all gears with an arbitrary tooth profile. A p* of Hypoid gears is ordinarily lapped after cutting and heat-treating. Since the time for lapping process is shortly a few to over ten minutes, the surface roughness is comparatively rough, for example as 5〜10 μmRy (≒1〜2 μmRa). Recently, the friction heat produced by the surface roughness becomes a question. For the sake of solving this problem the barreling process is effective.
If the barreling process will be utilized as a last machining, the surface of the gear is not only smooth like a mirror, but also it can remove a burr and a protrusion around a scratch produced during machining. As a result, it will contribute to the quality control of the gear. The shot peening and barreling processes can decrease the friction coefficient by improvement of the surface roughness. If the load carrying capacity of gears will increase, the automobile transmission can be designed to a small size, and ultimately it will contribute to the saving of energy as an ecological gear. Less
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