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No.29 (1982/12) >

 
Title :サトウキビの刈取機構に関する基礎的研究(農業工学科)
Title alternative :Fundamental studies on Sugar Cane Harvester.(Department of Agricultural Engineering)
Authors :泉, 裕巳
Authors alternative :Izumi, Hiromi
Issue Date :1-Dec-1982
Abstract :サトウキビの収穫, 輸送, 加工などの機械化を図るためには, 形状や物性値を明らかにすることが必要である。本章では, サトウキビNCo 376の形状, 物性を知るためにいくつかの基礎的な実験を行なった。測定結果は次のとおりであった。1.茎稈の含水率は登熟期に入ると低下し始め, 特に梢頭部にその傾向が著しかった。糖度と含水率(たとえば基部)との間には, r=-0.94の相関が認められた。2.貫入抵抗と含水率とは, 生育に伴って含水率が著しく減少する部位では, 高い相関を示している。貫入抵抗は, サトウキビ収穫機のデバイダや送りロールの設計にも有効な情報となる。3.圧縮試験により圧縮弾性率を求めたところ, 表皮の付いた基部で105kgf/cm^2,髄部で73kgf/cm^2,横断面方向に抜いた髄部で22.5kgf/cm^2であった。4.曲げ試験により弾性率を求めたところ, 茎稈上部で3.13×10^3kgf/cm^2,中部で2.25×10^3kgf/cm^2,基部で2.20×10^3kgf/cm^2であった。5.茎稈基部のポアソン比の測定を試みて, 表皮付きで0.344,髄部で0.467を得た。上述の物性値は, サトウキビNCo 376の平均的な値であり, サトウキビの品種はもとより, 生育条件によってかなり変動するが, 一応の指標とみなしうる。以上, 主としてNCo 376の物性値について報告したが, 先にも述べたように沖縄県においては, この品種の栽培が漸増している。また, 最多品種であるNCo 310はこれより軟らかいので, 沖縄県に適した収穫機の設計においては十分に有用であると考える。
Sugar cane cultivation occupies most important part of agriculture in Okinawa as main crop. However, the most part of working procedure while sugar cane cultivation relies upon manual work. This fact became a cause of decrease of farmer's income according to increase of wages of the farm work. Especially, harvesting work is not only complicated and the heaviest work but also concentrated in limitted short term. That is, how to save labor of the harvesting work is the most important subject in modernization of sugar cane cultivation. In order to solve this problem, several imported big harvesters were tried to introduce into Okinawa. However, those big machines could be used in only limitted area for the sake of complicated feature of the farm field or inconsolidated field conditions, and were not practical in Okinawa. In this point of view, this study was started intending to develop a harvester which can be used in the most fields in Okinawa. The harvester which can be used in the fields with special condition in Okinawa should be a smaller machine with high performance. So, it is essential to make clear fundamental conditions to develop a smaller and effective machine, when we intend to develope a sugar cane harvester useful in Okinawa. For this purpose, in the Chapter 2 in this study, physical properties of the sugar cane, which is the object of the harvesting, were tested. Namely, several characteristics and strength of the sugar cane under mechanical treatment were measured. These characteristics are important factors affecting structure, materials, and mechanism of the machine when canes are harvested, that is, whe the canes are raised, cut and treated mechanically. It is difficult to apply usual cutting theory of other crops to the sugar cane as the physical property of the cane is much different from that of other crops. So, at first, discussing on the cutting theory, it was made clear that rotating blade was more suitable than straight motion blade in the case of sugar cane harvesting. In the Chapter 3,in order to know value of torque in actual cutting work, several factors affecting statical cutting resistance of the fixed blade were studied, and the following results concerning cane cutting characteristics were obtained.
1. Cutting velocity heavily affected to the relation between wedge angle of the blade and cutting resistance, namely, deformation and failure. 2. In the low speed cutting (2.2mm/min) test, a fine positive correlation was found between average diameter of the cane and cutting resistance. The resistance increased proportionally to the diameter, and was 16-35mm of diameter. This relationship satisfied the following equation. Y=3.702X+9.967 ………………(4.1) 3. In the high speed (4.6m/sec) cutting test, correlation between each factors showed very high value as 0.96 between penetrating resistance and cutting resistance, and 0.94 between penetrating resistance and cutting energy. 4. Multiregression between wedge angle of the blade (K), cutting angle (C), diameter of the cane (D) and moisture content (M) was analized concernig cutting characteristics, and the following multiregression equation was obtained. E=0.12D-0.044M+0.017K+1.727 ………………(4.13) This means wedge angle affects more to the cutting energy than cutting angle as for shape of the blade. 5. The highest effect the cutting energy in the high speed test was the diameter of the cane, and increase of the wedge angle also increased the cutting energy, whereas increase of the moisture decreased cutting energy. 6. Multiregression equation concerning cutting resistanse was given by the following equation. R=3.757D-2.522M+0.176K-0.316C+156.536 ………………(4.17) This means increase of the cutting angle decrease the cutting resistance. 7. In the range of 15°-26° of the cutting angle, canes did not slip even in the case of free cutting. 8. Cutting characteristics in the high speed test relied upon rather the diameter and moisture content of the ca
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4029
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.29 p.87 -151
Appears in Collections:No.29 (1982/12)

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