热膨胀槽对硬质合金圆锯片空转噪声的影响

EFFECT OF HEAT EXPANSION SLIT OF SINTERED CARBIDECIRCULAR SAW ON ITS IDLE NOISE

为了揭示硬质合金圆锯片的热膨胀槽对锯片空转噪声的影响,分别测量了槽长l、槽宽b以及槽数N各不相同的硬质合金圆锯片在不同转速条件下的8个基本测点的平均A声级(?)_(PA)和平均声压级(?)_(pf)。在本实验的l值范围内,l对噪声基本没有影响。b=1mm和2mm的锯片,其噪声几乎没有差别。b大到4mm时,其噪声明显高于其它3个锯片。锯片转速较低(2500r/min和3000r/min)时,槽数对锯片噪声的影响不明显。锯片转速较高(3500r/min和4000r/min)时,N=3、4、5的各锯片的噪声也没有差异,而N=6的锯片噪声明显低于其它锯片。当转速n=4500r/min时,噪声随槽数的增多而升高,但N=6的锯片噪声明显低于N=3、4、5锯片。热膨胀槽的参数值各不相同的10个锯片,声压级峰值的频率都在4000Hz左右,该频率对人有明显影响。

In order to know the effect of heat expansion slit of sintered carbide circular saws on its idle noise, the average A overall sound pressure level (?)_(pA) and average band pressure level (?)_(pf)of 8 basic points under different revolution and length (1), width (b) and number (N) of slits were measured respectively. In this study, within 1, 1 did not affect on noise level when b=1 mm and b=2 mm the noise had almost no difference. When b was up to 4 mm, the noise level was muchhigher than other saws. When the revolution was low (2500 rpm and 3000 rpm), the number of slits did not change the noise very much. When the revolution was higher (3500 rpm and 4000 rpm), there is no difference among saws of N=3、4、5. But when N=6, the moise of saw was much lower than others. When revolution was at 4500 rpm, the moise level increased as the number of slits increased and the noise level of saw N=6 was much lower than others. The frenqueney range of the band at peak band pressure level was at about 4000 Hz, which are harmful to humanbeing