共查询到20条相似文献，搜索用时 953 毫秒
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张占宽 《林业机械与木工设备》2005,33(6):13-15
将未适张、辊压适张、锤击适张圆锯片装在不同直径的夹盘上，施以相同的夹紧力后进行振动模态分析。实验证明，不论是未适张圆锯片，还是辊压和锤击适张圆锯片，随着夹盘增大，锯片各阶固有频率都有不同程度的提高，其中辊压适张圆锯片二阶振动模态的固有频率没有增加或只有少量增加，锤击适张圆锯片四阶以上振动模态的固有频率有显著增加。 相似文献
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戴辉寿 《中南林业科技大学学报(自然科学版)》1981,(2)
带锯机是将带锯条挂在两个锯轮上,在动力带动下,锯条作高速转动而进行木材切削的一种设备。薄而长的带锯条,在高速转动的条件下切削木材,要承受切削力、进给力以及锯条与木材发生的摩擦力的作用。因此,要求带锯条有一定的刚度和稳定性,不然,就不能切削木材。提高锯条刚度和稳定性的方法,是对锯条进行辊压,使其具有一定的适张度和背缘度。 相似文献
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概况目前使带锯产生稳定性的有效方法有两种:加热适张度和辊压适张度,两种方法均能达到“口紧、腰软,背弓”。前者是新工艺,需要专用机床和熟练地操作,对中小型木材加工厂,一时还难普及。对于后一种产生适张度的关键性部件辊轮,普遍存在精度和曲率半径太小问题。“木工修锯技术”一书中辊轮曲率半径数据为R120,“林产工业”82年第二期“压锯机压辊的初步研究” 相似文献
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加热适张度是利用氧一乙炔焰,将锯身的一定部位加热,使该部在冷却收缩中产生同辊压张力一样的变形,从而获得适张度。圆锯片气焊加热适张度机配有带锯夹锯装置,可用于圆、带锯的加热适张度及辊压处理,实现了一机多用。经该机修整的锯片,具有作业时间短、适张度均匀且不易消失,锯末端加热部分不易变形,厚度均匀,锯切质量高等优点。 相似文献
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李军伟 《林业机械与木工设备》1999,(11)
1圆锯片适张度检查和修正的必要性锯片锯割时，圆锯做回转运动，圆锯片除了受木材摩擦力外，还受到离心力的作用。锯齿与木材摩擦产生的切削热量，在边缘处比中间部分大得多，所以外口膨胀伸长，边缘部分松驰。因离心力与回转速度（切线速度）的平方成正比，因此，转速大的锯片边缘部分较中央部分伸张的多，这也造成了边缘的松驰。由于锯片边缘部分和中央部分的张紧程度不同，因此在切割木材时，锯片不稳定，其圆周不能保持在一条直线上，而变成“波浪形”，导致锯割困难，锯出的材面不平，甚至无法进行锯割。为了克服这种现象，首先要对适… 相似文献
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为解决电链锯锯链使用寿命较短的问题,以电链锯锯齿温度场为研究方向,对锯齿温度场进行理论分析,得出锯切深度、切削速度、侧刃切削角三个主要研究变量;通过使用Abaqus软件分析以及实验探究,分析以上三个研究变量对电链锯锯切过程中锯齿温度变化的影响。验证了Abaqus建立的链锯锯切模型的可行性;链锯锯齿温度场受锯切深度、切削速度、侧刃切削角的影响;链锯锯切过程中,锯齿温度变化曲线呈现迅速上升、平稳上升、稳定不变三个阶段;保持其他条件不变,锯齿温度随切削深度增加而升高8%~13%,随切削速度增大而升高15%~20%,随侧刃切削角增大而降低22%~25%。 相似文献
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【目的】针对改进沙柳削片机切削过程中冲击力大、振动剧烈等问题,对其振动情况进行测试,为后续研究不同工作部件的振动幅度和频率对削片质量的影响及高效合理使用沙柳削片机提供技术参考。【方法】在空载和负载条件下,对沙柳削片机主要工作部件,即切削机构和进给机构组建多点振动测试系统。【结果】随着刀辊转速增加,削片机主要工作部件振动加速度呈先减小后增大的趋势,在整个频带上振动加速度自功率谱稳定;随着喂入辊转速增加,切削机构上下方向的振动加速度急剧增加,切削机构前后左右方向的振动加速度以及进给机构上下左右方向的振动加速度均呈先增大后减小的趋势,当喂入辊转速达到80 r·min-1时,削片机主要工作部件均振动剧烈;喂入量对进给机构上下左右方向的振动及切削机构上下方向的振动影响较大,随着喂入量增加,削片机主要工作部件的整体最大振动加速度也增大,在157 Hz处,进给机构上下方向振动的自功率谱呈先增大后减小的趋势;随着沙柳含水率增加,削片机切削进给机构的最大振动加速度减小,且在整个低频段削片机主要工作部件的自功率谱总体呈减小趋势;随着沙柳根部直径增大,切削进给机构各方向的振动加速度均增大。【结论】空载条件下,进给机构和切削机构在各个方向的振动加速度均较小;负载条件下,受刀辊转速、喂入辊转速、喂入量、沙柳含水率、沙柳根部直径的影响,进给机构和切削机构在各个方向的振动加速度均大幅度增加。 相似文献
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吕天赦 《中南林业科技大学学报(自然科学版)》1983,(1)
本文对带锯条辊压后的变形、应力变化、张紧应力以及由此而导出的其他问题进行了分析,提出不同于《带锯条辊压的应力分析》一文的见解。 相似文献
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In this paper, a 2-D and 3-D finite element model of roll tensioning process of circular saw blade were established by Static/General module of ABAQUS software based on finite element method. The rolling force and tensioning stress distribution of circular saw blade were calculated by these two models which were proved to be true and reliable. The effects of yield strength of circular saw blade on tensioning stress distribution and rolling force were studied. The research achievements showed that a circular saw blade made with high yield strength obtained a higher tangential compressive stress and radial compressive stress in the rolled region during roll tensioning process, which has both advantages and disadvantages for the stability of the saw blade. Besides, a circular saw blade made with high yield strength also put forward higher requirements for roll tensioning equipment because of the large rolling force during roll tensioning process. 相似文献
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Summary In a typical sawmill, about 12% of the wood which is cut is reduced to sawdust. Further material is lost during subsequent planing. A substantial part of this large loss of a costly natural resource can be saved by the use of thin, stable sawblades, but only if proper saw tensioning conditions are developed. The thickness of a stable sawblade can be minimized through optimal tensioning, an increasingly urgent objective because of sharply rising raw material costs. A theoretical model is presented which accurately describes the development of residual stresses in a roll tensioned circular sawblade and the resulting changes in saw critical speed. This model is essential for the reliable prediction of optimal tensioning conditions for any given saw operating state, and for the development of automated control of the tensioning process. An example is presented of an optimally tensioned circular sawblade for which a 40% thickness reduction is achieved compared with an equivalent untensioned sawblade with the same critical speed.Paper awarded First Place Wood Award Price, Forest Products Research Society, June 1981 相似文献
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The determination of particleboard (chipboard) mechanical strength critical stresses and their correlation to a specific cutting force in chipboard milling are introduced. This correlation is based on bending and indentation tests, on a finite elements method (FEM) simulation of the chip formation and flow mechanism in chipboard milling, as well as on cutting force components measurements. The obtained results, by means of these procedures, were used to verify the FEM calculated milling force time course and to explain the chip formation and the cutting force fluctuation. Moreover, owing to these results, the experimentally and analytically determined chipboard and layer elasticity, as well as small and large scale plasticity strength values, were correlated to the corresponding specific cutting force, considering concrete cutting edge revolving positions during milling. In this way, chipboard materials strength critical stresses can be determined automatically, taking into account their correlation to the specific cutting force, individually defined through cutting force components measurements. The developed procedure can be used beneficially in monitoring the mechanical strength properties of chipboards under production conditions. 相似文献
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伐区采育作业系统综合效益评价的研究 总被引：16，自引：6，他引：10
在定量计算各伐区采育作业模式的经济效益指标和定位测定由这些作业模式所造成的土壤肥力、迹地更新效果和蓄水保土等指标变化量的基础上，采用多目标决策和层次分析等方法，定量计算各伐区采育作业模式的综合效益（经济效益和生态效益），改变单纯以经济效益为唯一目标确定伐区工艺方案的传统方法。计算结果表明，“４０％择伐－原木人力集材－归带处理采作伐剩余物－人工促进天然更新”这一作业模式是马尾松天然次生林伐区作业的优 相似文献
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刀具前角与切削量对柠条材切削力影响的研究 总被引：1，自引：0，他引：1
内蒙古地区灌木资源十分丰富,柠条、沙柳等灌木是防风固沙的优良树种,同时又是生产人造板的优质原料,但在削片加工过程中存在木片质量不稳定、树皮切不断等问题。从刀具前角和切削量对柠条材切削力的影响进行深入研究,寻求柠条材最佳切削参数,以改进削片机性能,提高柠条材削片质量,为新型沙生灌木削片机的设计与研制提供理论依据。 相似文献
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为了明确影响灌木材端向切削力的主要因素,改进削片机性能,提高灌木材削片质量,笔者研究了不同刀具前角、切削厚度和不同含水率对沙柳(Salix psammophila)材端向切削力的影响。结果表明刀具前角对法向力的影响较小,对主切削力影响较大;切削厚度对主切削力的影响较为明显,随切削厚度的增加,主切削力明显增加;沙柳材含水率15％以下主切削力随含水率增加略有增大,之后逐渐减小,其中含水率在30％-70％之间时,切削力变化不大。 相似文献
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Katsutoshi Fujiwara 《Journal of Wood Science》2002,48(5):359-364
The validity of a bandsaw roll-tensioning theory developed by the author is verified based on a model experiment. It is shown that the actual roll-tensioning process can be clearly explained by this theory. Roll-stretching force transmission coefficients are introduced in this theory. These coefficients, which indicate the magnitude of the compression force parallel to the bandsaw surface at the roll-stretching position, are affected by the thickness of the bandsaw blade, the radius of the bandsaw blade vent at the measurement of tension, and the straightness of the bandsaw blade at the measurement of crown back, among others. For the practical use of this theory, therefore, it is necessary to determine the proper magnitude of these coefficients based on tensioning experiments. 相似文献
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