揹負式割草機噪音之調查研究

Investigation of the Noise for Brush Cutters and Grass Trimmers

葉仲基(Chung-Kee Yeh) ； 宋敏港(Min-Gang Sung) ； 林桂儀(Kuei-Yi Lin)

《應用聲學與振動學刊》 4卷1期 (2012/06) Pp. 29-42

https://doi.org/10.6282/JASV.2012.4.1.04

摘要

國內使用揹負式割草機的勞工估計有近萬人，由於該型割草機具有價格便宜、操作簡易及施作迅速等優點，故仍為目前從事園藝業及清除雜草使用相當普遍的割（除）草工具。本研究主要針對使用者進行噪音之現場量測調查，暸解目前使用揹負式割草機產生之音量值。測試用之揹負式割草機有軟管式與硬管式兩種，刀具分別為牛筋繩與二片刀，使用之量測儀器則為噪音劑量計與音頻分析儀。噪音劑量的量測結果得知：無論是軟管或硬管式割草機，相同割草機使用二片刀會比使用牛筋繩高3至4分貝不等；使用相同刀具時，軟管式割草機都比硬管式稍高1至2分貝不等。而由噪音音頻的頻譜分析得知：硬管式割草機當轉速提升時，最大聲壓位準發生之頻率，有往上提升的趨勢，從怠速的500至2,000 Hz，變成低速多集中在500至3,150 Hz，再變成高速多集中在500至4,000 Hz；而軟管式割草機的趨勢也大致相同，怠速集中在630至2,000Hz，低速集中在800至2,000 Hz，高速集中在500至4,000 Hz；由聲壓位準量測結果亦得知，硬管式割草機無論在怠速運轉、低速操作、與高速操作下之聲壓位準皆比軟管式割草機來得大。

關鍵字

揹負式割草機 ； 噪音 ； 劑量計 ； 音頻分析儀 ； 分貝

並列摘要

The number of users of brush cutters and grass trimmers is about 10,000 in Taiwan. The advantages of these kinds of machines are cheap price, easy use and fast operation. Therefore, they are widespread handheld power tools for mowing in the field of horticulture and remove of weeds. The purpose of this study is to collect the data of noise dose and sound pressure level in order to understand whether these machines will cause the operator's hearing damage. Two types of machine were used: backpack type and shoulder type. The cutting devices were monofilament line and rectangular blade. The instruments used were noise dosimeters and a precision sound pressure level meter. The measurements of noise dose show that time weighted average (TWA) sound level of a machine with rectangular blade is 3-4 dB higher than TWA of the same machine with monofilament line, no matter what types of machine. With the same cutting device, TWA of the backpack type is 1-2 dB higher than that of shoulder type. From the measurements of sound pressure level (SPL) it can be concluded that the maximal SPL will move toward a higher frequency domain when the rotation speed of shoulder type machine increases. The max SPL is in the range of 500-2,000 Hz for engine idle speed, 500-3,150 Hz for low speed operation, and 500-4,000 Hz for full throttle operation. The results of backpack type machine are similar. The max SPL is in the range of 630-2,000 Hz for engine idle speed, 800-2,000 Hz for low speed operation, and 500-4,000 Hz for full throttle operation, however. The max SPL of shoulder type are higher than that of backpack type regardless of rotation speeds of machines.

並列關鍵字

Grass Trimmers ； Noise ； Dosimeter ； Sound Pressure Level Meter ； dB