各种阻尼横截圆锯片噪声的研究

各种阻尼横截圆锯片噪声的研究在锯片厚度、直径、齿形及工件厚度保持不变时，我们对各种阻尼圆锯片在不同转速下的空转噪声和切削噪声的分贝值〔ｄＢ（Ａ）〕减少量进行了分析比较，提出了一种评价阻尼圆锯降噪性能的方法。该项研究无意深究每种阻尼圆锯片的降噪机理，只...     

圆锯片振动模态分析技术研究进展

为开展国产圆锯片结构动力特性研究,做好锯片减振降噪和结构稳定性工作,重点介绍了国内外圆锯片振动模态分析技术研究成果,包括模态理论计算、计算模态分析和试验模态分析方面的最新研究进展及其不足。在归纳和总结基础上,提出了符合我国国情的提高圆锯片振动模态分析工作的研究思路,以期对提升圆锯片设计水平与制造质量,促进我国圆锯片制造技术创新与发展具有指导意义。     

苏联研制的新型圆锯片

为克服圆锯机存在的锯路宽度大、噪声大、横向刚度低等缺点,苏联研制出了几种新型结构的圆锯片.简介如下:1.阻尼圆锯片硬质合金齿圆锯片锯切锯路宽度较大,如直径为250—400mm的硬质合金齿圆锯片的锯切锯路宽度为3.4—4.1mm;又由于它开有补偿槽而降低了锯片的横向刚度,且工作噪声大.苏联乌拉尔林学院研制的新型结构圆锯片,具有减少锯路宽度、增大锯片横向刚度、提高其热稳定性以及降低噪声等优点.     

基于有限元法的圆锯片振动特性研究进展

圆锯片是一种应用非常广泛的刀具,但由于其加工过程中常常出现振动现象,导致其使用寿命剧减,加工质量下降等现象。为了做好圆锯片的设计、制造和使用中的"减振降噪"工作,文中通过对国内外基于有限元法的圆锯片振动特性模态分析的研究成果进行总结和概述,以期为促进圆锯片改良设计的研究工作,提高圆锯片的工艺制作水平和加工水平提供借鉴。     

地铁上盖物业开发车辆段减振降噪措施

介绍地铁车辆段上盖物业开发业态、结构形式及特点。分析振动噪声产生的原因及传播途径,介绍地铁上盖车辆段减振降噪的主要措施及使用范围,从项目规划、车辆段设计、减振降噪措施选择等方面给出地铁车辆段上盖开发及减振降噪的建议。     

圆锯片动力学理论分析与试验研究发展

圆锯片作为各种锯机的切割刀具,用途很广泛,但其在使用过程中易产生振动和噪声,不仅降低了锯切质量,缩短锯片的使用寿命,还会使锯片产生变形,甚至引起安全事故。因此,对圆锯片振动的动力学特性研究尤为重要。本文通过对中外专家学者取得的圆锯片结构动力学理论及其试验成果的总结,提出应高度重视圆锯片失稳性能等理论与试验研究方向,以期促进我国对圆锯片技术的基础应用性研发工作的发展,为提高我国圆锯片行业的综合经济技术水平提供借鉴。     

浅析纺织车间的噪声及降噪措施

文章论述了纺织车间降噪的意义,分析了纺织车间噪声的来源,提出了全面实施降噪的措施及原则。     

木工平刨床噪声及其控制

试验研究影响木工平刨床噪声的主要因素，即刀轴转速、树种、工件宽度、切削深度、机床结构和维护等。试验和分析木工平刨床空转和切削时的噪声源、噪声频率特性和各种降噪方法。采取最佳的降噪方法，整机的空转和切削噪声明显下降。     

产业用纺织品隔声降噪研究进展

产业用纺织品的隔声降噪功能可通过改变织物结构、纤维特性及涂层后整理等方式实现。概述了材料降噪原理及种类,总结了影响产业用纺织品隔声降噪性能的因素,介绍了产业用纺织品不同降噪方法的研究现状,重点介绍了通过涂层方式以纳米材料作为填充物构建复合降噪结构体,制备隔声降噪产业用纺织品的研究进展。     

粮食干燥中的风机噪声控制

论述了粮食干燥过程中主要噪声产生根源及改良措施.通过噪声产生机制、传播机理的分析,针对主要噪声声源风机结构特点,采取阻尼加吸声和旁通管反声降噪物理措施,可实现粮食干燥过程中噪声控制在85 dB(A)以下,优化工作环境,提高工作效率,便于安全生产.     

干切混凝土时金刚石锯片振动及噪声的研究

干切混凝土时,金刚石锯片在实际工作过程中产生的振动和噪声是非常严重的。文章从理论上分析了混凝土锯切过程中的强振动、高噪音的原因。通过改变锯切速度、进给速度、切深以及通过采用两种不同的基体结构的锯片,研究了不同的切削参数以及锯片的结构对锯片振动和噪声的影响。在不同的锯切工艺参数和锯片结构下,测量了噪声值、噪声功率、噪声电压、振动功率和振动幅值,并对其进行频谱分析。可以从锯片的基体结构、金刚石节块的结构、锯切工艺以及锯机的整体性能等方面来进行改进,从而达到降低噪声与振动的目的。本文在理论分析和实验的基础上提出了一些降低噪声和振动的方法。     

圆锯片轴向多点加压适张及振动模态分析

提出一种新的圆锯片适张方法——轴向多点加压适张。通过振动模态分析实验表明压点的分布和压力的大小对锯片各阶振动固有频率都有明显的影响,其振型及各阶振动固有频率的变化趋势初步证明这是一种有研究前景和应用价值的圆锯片适张方法。     

Aktive Geräuschminderung beim kreissägen

A number of measures can contribute towards noise abatement in circular saws which, when combined, result in a considerable reduction in noise level. The idling noise of circular saw blades is affected to a large extent by the geometry of the toothed rim, damping of blade trunk and circumferential speed. Cutting noise is predominantly related to damping of the tool and to wear. Investigations proved that a reduction in cutting speed, from the conventional 70 m/s to 50 m/s, results in a lessening of cutting noise. At the same time tool wear was reduced and edge quality improved.     

Vibration of circular saws containing slots

The natural modes of transverse vibration of circular saws containing radial slots are analyzed in this paper. Incision of equally-spaced asymmetry, equally sized, radial slots at the rim of a saw creates in some, but surprisingly not all, of the vibration modes of the circular saw. It causes the repeated natural frequencies in these asymmetric modes to split into two distinct values. These vibration modes are called the split modes. The vibration modes associated with the repeated natural frequencies, typical of the axisymmetric saw plate, are called the repeated modes. A relationship predicting which vibration modes are split and which are repeated for any configuration of slots on the saw is presented in this paper. Further, it is shown that parametric, transverse vibration instability can be excited in the split modes of the slotted saw by the saw guides and the workpiece. These parametric vibrations can not be excited in the repeated modes. The theoretical predictions of split and repeated vibration modes and the excitation of parametric instability are confirmed by experiments.     

Geometry of kerf when curve sawing with a circular rip-saw

Rip-sawing following the curvature of a crooked log means advantages for yield. However, the possibility to saw in a narrow curve with a circular saw blade is limited because of the inherently flat geometry of circular saw blades. For a double arbour circular saw the situation is even more problematic because the two blades have a certain overlap and thus, the two arbours are not positioned in the same horizontal position. In this study, a theoretical geometrical study of the creation of a kerf with a single circular saw blade and with a double arbour circular saw with two saw blades was examined. Results for stiff saw blades show that the kerfs become in general curved and inclined (tilted) in the vertical direction and also that the width of the kerfs for double arbour saws becomes wider at the top and bottom of the cant than in the middle. Additionally, the sawn boards obtain varying thickness along their width because of the varying kerf width. A comparison with experimental thickness data from four test sawings at a sawmill indicates that the theoretical results are valid and that curve sawn boards become thinner than straight sawn boards.     

Why are guided circular saws more stable than unguided saws?

This paper indicates why guided circular saws are typically more stable than similar unguided saws. It introduces lateral stiffness as a practical stability measure to quantify the ability of both circular saw types to resist lateral cutting forces without large deflections. Proper tensioning is shown to be very important as a means of maximizing sawblade stiffness. Previously used measures of sawblade dynamic stability, such as critical speed margin and lowest natural frequency, cannot adequately account for spatially dependent features such as guides, and can give, misleading stability comparisons.     

木工宽带砂光机噪声的研究

首次通过噪声数据的频谱分析,来准确分析国内目前普遍应用的木工宽带砂光机(BSG2713)的噪声频率组成,主要为中、低频;准确分析噪声源位置,并探讨可行的降噪措施。     

North American techniques for circular saw tensioning and leveling

This paper describes typical processes used in North America for tensioning and leveling circular saws. It concentrates on the methods used to evaluate the tensioning and leveling state of a circular saw, so that appropriate corrective actions may be taken. The paper gives practical details of the measurement processes involved and explains the theory of how they work.     

高速列车车厢内噪声主动控制技术综述

传统的高速列车噪声控制多采用隔音、减振等被动的降噪方法,仅对中高频噪声的控制有效,无法满足时速300 km以上高速列车的噪声控制要求.而主动噪声控制技术通过有目的地产生一个次级声信号来消弭低频噪声,适于高速列车车厢内噪声控制.无论次级声源控制还是次级力源控制,都要增强系统的可靠性和鲁棒性,而宽带噪声控制的多通道自适应噪声主动控制技术将会成为该领域的研究热点.