• 한국농공학회지
• /
• 제15권1호
• /
• pp.2925-2933
• /
• 1973

For the efficient utilization of farm machines on the inclined uqland, work performance in plowing, harrowing and terracing and critical workable gradients were tested on three farm machines which are 47 ps-farm tractor, 8 ps-power tiller and 5 ps-power tiller. The results of this study are summarized as follows; 1) The steeper the slope of the upland was the more inefficient the work performance of all machines was. 2) The critical workable gradients of the machines were proved as 14 for 47 ps-farm tractor, 12 for 8 ps-power tiller and 10 for 5ps-power tiller. 3) Plowing in the way of turning the furrow slices against the slope in order to build up terraces, the critical workable gradients were 8 for 47 ps-farm tractor and 8 ps-power tiller and 6 for 5 ps-power tiller. 4) Two-way plow is recommended for plowing with farm tractor on inclined upland, and high lug of tire would be good to prevent the slippage, and side valance-weight should be attached to power tiller for preventing its overturning.

• Journal of Biosystems Engineering
• /
• 제2권1호
• /
• pp.49-54
• /
• 1977

In order to obtain the field efficiency of the power tiller plowing on the various size of and its length-width field tests were performed with 8ps.10ps. power tiller popularly used in the korean rural area, and Satoh 5ps. made in Japan, Land Master 5ps. made in England were tested to compare with the field efficiency of the above power tillers. The results obtained in this tests were as follows ; 1. In considering of the resting time and the refueling time and others, the field efficiency of Satoh was the highest among the power tillers as to be 80%, at the 8ps. power tiller 76.5%, at the 10ps. power tiller 79.3% and the lowest field efficiency was obtained at the Land Master as 75.7%. 2. The field efficiency of the each power tiller increased as the ratio of the length to width of the field was increased. 3. The increasing rate of field efficiency was much bigger in the below the ratio of 5 : 1 but at the upper ratio increased above, the ratio was nearly constant. 4. The field efficiency of the power tiller was higher at the smaller power tiller than the larger, except the Land Master , because of easily operating and turning of the power tiller by virtue of its lighter weight.

• Journal of Biosystems Engineering
• /
• 제12권3호
• /
• pp.17-29
• /
• 1987

A 10-degree of freedom mathematical model of motion for power tiller-trailer system was developed. This model can predict motion characteristics of power tiller trailer system while travelling over smooth and irregular ground surfaces under various operating conditions. The model provide, the fundamental data needed to improve the stability of power tiller-trailer systems.

• Journal of Biosystems Engineering
• /
• 제4권1호
• /
• pp.67-74
• /
• 1979

This survey was carried out to grasp the actual condition of a power tiller utilization . Now, the power tiller has become the leading machinery in the field of agriculture throughout the country . Two hundred farm houses, located in the provincial districts of Kimcheon and kum0rung, hav etaken part in the survey from October 1, 1976 to September 30, 1977. The results are summarized as follows . 1. The average size of cultivated land of a farm household in the districts surveyed was 1.77ha which was bigger than that of whole country. And the average age of power tiller drivers was analyzed in which only 105 of total drivers was on their 30's. 2. Distribution of a power tiller utilization was appeared to be 34.4% for transporting , 24% for tilling , 23% for pumping , 11.5% for threshing and 6.6% for spraying. 3. Frequency of a power tiller utilization was high during the month of June, July and October while it was low during February and December . 4. Distribution of repairing cost was 8.5% for trailer, 7.1% for throttle lever and 6.7% for casket, respectively. The annual cost for repairing was 5,290 won.5. The annual cost for using a power tiller was composed of 51.5% of fixed cost and 48.5% of operating cost. 6. Economic analysis showed that it was not economically practical for individual ownership of a power tiller on the farm surveyed. Therefore, custom operation and joint ownership by a few farmers were recommended.

• Journal of Biosystems Engineering
• /
• 제6권1호
• /
• pp.28-38
• /
• 1981

동력경운기(動力耕耘機)의 효율적(效率的)인 이용(利用)과 고장(故障)으로 인(因)한 문제점(問題點)과 그에 따른 대책(對策)을 강구(講究)하기 위(爲)한 기초자료(基礎資料)를 제시(提示)코저 전국(全國) 8개도 278농가(農家)를 대상(對象)으로 동력경운기(動力耕耘機)의 각종(各種) 고장(故障) 및 수리실태(修理實態)를 조사분석(調査分析)한 결과(結果)는 다음과 같다. 가. 고장빈도(故障頻度) 동력경운기(動力耕耘機)의 대당(臺當) 년간(年間) 고장발생(故障發生) 빈도(頻度)는 9.05회(回)이었으며 평균(平均) 39.1시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되었다. 고장빈도(故障頻度)가 가장 높았던 곳은 점화연료공급계통(點火燃料供給系統)으로서 2.02회(回)로 전체고장(全體故障)의 22.3%를 차지하였고, 그 다음이 부속작업기(附屬作業機) 시린더계통(系統), 주행장치등(走行裝置等)의 순서(順序)로 나타났다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年水別) 고장(故障) 발생빈도(發生頻度)는 구입후(購入後) 6년(年) 이하(以下) 경과(經過)된 기계(機械)에서 37.7시간(時間) 사용(使用)에 1회(回)의 고장(故障)이 발생(發生)된 것으로 나타나 가장 높았고 그 다음이 구입후(購入後) 2년(年) 미만(未滿)된 기계(機械)로서 38.6시간(時間) 작업(作業)에 1회(回)이 고장(故障)이 발생(發生)되었다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 고장(故障) 발생빈도(發生頻度)는 석유(石油)엔진이 36.3시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되어 디젤엔진의 42.8시간(時間)보다 높았고 마력별(馬力別)로는 석유(石油)엔진의 경우(境遇) 8마력(馬力)이 10마력(馬力)보다 고장(故障) 발생빈도(發生頻度)가 높게 나타났다. (4) 동력경운기(動力耕耘機) 월별(月別) 고장(故障) 발생빈도(發生頻度)는 10월(月)에 가장 낮아 51.5시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)되었고 그 다음이 6월로 49.7시간(時間) 작업(作業)에 1회(回)의 고장(故障)이 발생(發生)된 것으로 나타나 작업시간(作業時間)이 많았을 때 고장(故障) 발생빈도(發生頻度)는 상대적(相對的)으로 적었던 것으로 나타났다. 나. 수리장소(修理場所) (1) 동력경운기(動力耕耘機) 고장시(故障時)의 수리장소(修理場所)는 자가수리(自家修理)가 평균(平均) 45.3%이었고 공장수리(工場修理)가 54.7%로 나타나 공장수리(工場修理)가 자가수리(自家修理)보다 많았다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年數別) 수리장소(修理場所)는 구입후(購入後) 경과년수(經過年數)가 길어질수록 공장수리(工場修理)보다 자가수리(自家修理)가 많아지는 것으로 나타났다. (3) 동력경운기(動力耕耘機) 자가수리율(自家修理率)은 디젤엔진이 석유(石油)엔진보다 높았으며 석유(石油)엔진에서는 10마력(魔力)이 디젤엔진에서는 8마력(魔力)이 높았다. (4) 고장부위별(故障部位別) 자가수리(自家修理) 비율(比率)은 조향장치(操向裝置)가 가장 높아 66.7%였으며 그 다음이 점화연료계통(點火燃料系統)인 것으로 나타났고 자가수리비율(自家修理比率)이 가장 낮는 곳은 부속작업기(附屬作業機)로서 26.5%에 불과(不過)하였다. 다. 고장원인(故障原因) (1) 동력경운기(動力耕耘機) 고장원인(故障原因)은 기계(機械)의 노후(老朽)에 의(依)한 고장(故障)이 년간(年間) 대당(臺當) 5.18회(回)로 전체(全體)의 57.2%를 차지하여 가장 많았고 정비불량(整備不良)과 과부하(過負荷)로 인(因)한 고장(故障)이 전체(傳遞)의 37.7%이었다. (2) 동력경운기(動力耕耘機) 구입후(購入後) 2년(年) 미만(未滿)의 기종(機種)에서는 정비불량(整備不良)으로 인(因)한 고장(故障)이 많았던 반면(反面) 노후(老朽)로 인(因)한 고장(故障)이 적었다. (3) 동력경운기(動力耕耘機) 고장원인(故障原因)은 기종별(機種別) 마력별(馬力別) 공(共)히 노후(老朽)로 인(因)한 고장(故障)과 과부하(過負荷)로 인(因)한 고장(故障)이 대부분(大部分)이었으며 특히 석유(石油) 5마력(馬力)엔진에서는 과부하(過負荷)로 인(因)한 고장(故障)이 월등히 높았다. (4) 동력경운기(動力耕耘機) 부위별(部位別) 고장원인(故障原因)은 시린더 계통(系統)과 주행장소(走行場所)의 고장(故障)에서는 주(主)로 노후(老朽)에 의(衣)한 원인(原因)이 많았던 반면(反面) 점화연료계통(點火燃料系統)의 고장(故障)에서는 정비불량(整備不良)으로 인한 고장(故障)이 많았다. 라. 수리비율(修理(比率) (1) 동력경운기(動力耕耘機) 년간(年間) 대당(臺當) 수리비(修理費)는 34,509원이었고 동력경운기(動力耕耘機) 1시간(時間) 수업당(修業當) 평균(平均) 수리비(修理費)는 97원이었다. (2) 동력경운기(動力耕耘機) 기종별(機種別) 수리비(修理費)는 석유(石油)엔진이 40,697원으로 디젤엔진의 28,322원보다 훨씬 많았다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 1시간(時間) 수업당(修業當) 평균(平均) 수리비(修理費)는 석유(石油)엔진이 108원으로 디젤엔진의 86원보다 많았으며 마력별(馬力別)로는 차이(差異)가 없었다. (4) 동력경운기(動力耕耘機) 고장부위별(故障部位別) 년간(年間) 수리비(修理費)는 시린더 계통(系統)이 13,036원으로 가장 많았으며 조향장치(操向裝置)가 362원으로 가장 적었다. (5) 동력경운기(動力耕耘機) 1회(回) 수리시(修理時)의 평균(平均) 수리비(修理費)는 3,713원이었으며 시린더계통(系統)이 10,598원으로 가장 많았고 조향장치(操向裝置)가 1,006원으로 가장 적었다. 마. 자가수리소요시간(自家修理所要時間) 및 고장(故障)으로 인(因)한 불가동시간(不稼動時間) (1) 동력경운기(動力耕耘機) 년간(年間) 대당(臺當) 자가수리(自家修理) 소요시간(所要時間)은 8.36시간(時間)이었고 고장(故障)때문에 작업(作業)하지 못한 시간(時間)은 년간(年間) 대당(臺當) 93.5시간(時間)이었다. (2) 동력경운기(動力耕耘機) 사용년수별(使用年水別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 6년이상(年以上) 경과(經過)된 기계(機械)에서 21.3시간(時間)으로 가장 높았고 고장(故障) 때문에 사용(使用)하지 못한 시간(時間)은 2년(年) 미만(未滿)된 기계(機械)에서 년간(年間) 대당(臺當) 127.13시간(時間)으로 나타나 가장 높았다. (3) 동력경운기(動力耕耘機) 기종별(機種別) 자가수리시(自家修理時)의 1회(回) 수리당(修理當) 소요시간(所要時間)은 디젤엔진이 10.66시간(時間)으로 석유(石油)엔진의 6.48시간(時間)보다 많았고 고장(故障)으로 인(因)하여 가동(稼動)하지 못한 시간(時間)은 석유(石油)엔진이 년간(年間) 대당(臺當) 99.4시간(時間)으로 디젤엔진의 88.67시간(時間)보다 많았다. (4) 동력경운기(動力耕耘機) 마력별(馬力別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 석유(石油)엔진 디젤엔진 공(共)히 8마력(馬力)이 가장 적어 석유(石油)엔진 3.78시간(時間)이었고 디젤엔진은 8.25시간(時間)이었다. (5) 동력경운기(動力耕耘機) 고장부위별(故障部位別) 자가수리시(自家修理時)의 1회수리당(回修理當) 소요시간(所要時間)은 시린더 계통(系統)이 가장 많은 32.02시간(時間)이었고 고장(故障)으로 인(因)하여 가동(稼動)하지 못한 시간(時間)은 시린더 계통(系統)이 가장 많아 년간(年間) 대당(臺當) 37.30시간(時間)이었다.

• Journal of Biosystems Engineering
• /
• 제10권1호
• /
• pp.1-12
• /
• 1985

The two agricultural zones, mid-and-northen region and southern region, were established according to the possibility of double cropping in the paddy field. For each agricultural zone typically mechanized farming systems with a power tiller for cultivating rice, barley and soybean were established. A computer program, which determines the optimum size of power tiller for the given farm size, the ratio of paddy area to total area and the ratio of double cropping area to the paddy area, was developed. The computer program was executed for the farm sizes, 1 to 3 ha, and the ratios of paddy area to the total area, 60~80%, and the ratio of double cropping area to the total paddy area, 70%. The following conclusions were drawn from analyzing the computer outputs. 1. In the mid-and-northern region, a smaller power tiller (5 or 6 PS) appeared to be more economical for the farm size up to 3 ha. From the viewpoint of fuel consumption a 6 PS power tiller appeared to be more favorable. 2. In the southern region, a smaller tiller (5 or 6 PS) appeared to be more economical for the farm size up to 1.5 ha. But, a larger power tiller (8 or 10 PS) appeared to become more economical as the farm size and the barley planted area increased. 3. For the southern region where rotary tilling is heavily required due to double cropping, it is recommended to develop a power tiller which weighs light like the conventional 5 or 6 PS small power tiller but has lager power.

• Journal of Biosystems Engineering
• /
• 제5권2호
• /
• pp.26-39
• /
• 1980

A study was investigated to find out the mechanical optimum conditions of power tiller-plow system on both paddy field and upland. Mathematical model was developed for the theoretical analysis of this system and the experimentation on the field was carried out with two different sizes of 5PS and 8PS power tiller equipped with rubber tire. 1) The relationship between the plowing depth and draft resistance of the power tiller-plow system was a quadratic function. 2) The minimum point of the specific draft resistance of the 5 PS plow was found at the smaller plowing depth than that of 8 PS plow, therefore we can find that the curved surface of 5PS plow bottom should be improved for the effective plowing operation. 3) As the improvement of the mechanical balance by the desirable change of the curved surface of plow bottom, the relative position of hitch point and dimension of plow beam would be realized, the 5 PS power tiller could be used to plow deeply (about 16-17cm). 4) The virtual acting point of the total draft resistance on the plow bottom approached to the land side as the plowing depth increased. 5) The resultant of vertical reaction force $R_2$ on the landside was increased with the plowing depth, while the vertical reaction force $R_1$ on the wheel was decreased as the slope angle of the body of power tiller increased. 6) For the effective plowing operations ; a) The slope angle of the body should be as small as possible. b) The diameter of the wheel should be as small possible. c) The horizontal and vertical distances $l_2, h_1$ between the wheel axis and plow bottom should be as large as possible. 7) To use the 5PS power tiller as the major unit of agricultural machinery, the curved surface of the 5 PS plower bottom and the mechanism of attachment between the power tiller and the plow should be changed as the indications of this study, and in addition to these, the new operation method of the field work should be developed.

• Journal of Biosystems Engineering
• /
• 제8권1호
• /
• pp.30-37
• /
• 1983

Frequent breakdowns of power tiller, particularly in the peak labor constraints, have been a cause of decreasing machine productivity and its efficient utilization. To keep power tiller always ready to work, it may be necessary to identify the failure characteristics of some major parts of power tiller, and to have those parts replaced accordingly before they show the symptom of mulfunction. This study was conducted to identify the failure characteristics of some major parts of power tiller and to estimate their lives (MTBF) using a Weibull distribution function. The result showed that about half of breakdowns currently being occurred may be reduced through timely replacement of those part having wearout failure characteristics.

• Journal of Biosystems Engineering
• /
• 제15권2호
• /
• pp.143-150
• /
• 1990

This study was conducted to estimate the ratio of Repair & Maintenance (R&M) costs to purchasing price that is one of the important factors for calculating the management costs of farm machinery. For this purpose, hour of use and R & M costs of power tiller and its attachments utilized results that were investigated with 400 sample units, 50 units by years of use from 1 to 8 years in 1988. The results obtained are summarized as follows; 1. The ratio of R & M costs per hours and annual R & M costs, accumulated R & M costs when sercice life of power tiller is 7 years were 0.017%, 5.50% and 38.52%, respectively. And in case of rotary, these ratio when its service life is 6 years were 0.072%, 7.16% and 43.0%, respectively. 2. The relationship between accumulated hours of use(t) and accumulated R & M costs(Y) of power tiller and its attachments were $Y=19.3t^{1.3}$ in power tiller, $Y=0.03t^{2.09}$ in plow, $Y=48.84t^{1.25}$ in rotary and $Y=7.45t^{1.15}$ in trailer. 3. The ratio of accumulated R & M costs to purchasing price when service life of power tiller is 7 years was 38.5%, and in case of rotary, this ratio when its service life is 6 years was 43.0%.

• Journal of Biosystems Engineering
• /
• 제13권2호
• /
• pp.1-8
• /
• 1988

A scale model of power tiller-trailer system with the same kinematic characteristics was constructed one eighth of the actual size to validate the effectiveness of mathematical model of motion. The parameters for the scale model of power tiller-trailer system were measured by a series of laboratory experiments. Validation tests for the: scale model was conducted under several ground and operating conditions. The tests were performed on artificial ground surfaces with several kind, of slope and obstacle. The travel path of the scale model was photographed successively in three directions. The travel paths obtained from both the film analysis and the simulation model appeared to be consistent with each other. It was concluded that the simulation model could be used to predict the motion of actual power tiller-trailer system if the parameters for actual power tiller and trailer are provided.