数控凸轮轴磨床磨削性能研究

发布时间：2018-05-12 05:29

本文选题：凸轮轴磨床 + 高速磨削　；参考：《吉林大学》2017年硕士论文

【摘要】：随着国家对环保的重视,汽车和内燃机的排放要求更加严格,对控制气门开闭机构的凸轮轴制造也提出的新的要求,对气门开闭进行更准确的控制,对凸轮轴的相位角和升程误差精度要求提高,传统的凸轮轴靠模加工方法很难达到要求,这就促使数控凸轮轴磨床得到快速发展和普及,数控凸轮轴磨床大多采用CBN砂轮磨削,砂轮线速度得到了提高,加工效率和表面质量也得到了提高,但也带来的新的问题。如:砂轮线速度提高后对切向磨削力和砂轮主电动机功率的影响;CBN砂轮修整;砂轮线速度提高后冷却及表面损伤的问题等。数控凸轮轴磨床的节能环保是我们所追求的,磨削的比磨削能比其它加工方法大很多倍。国外的凸轮轴磨床总功率达到90k W左右,而国内的凸轮轴磨床总功率有的已经达到120k W左右,这使得凸轮轴磨削加工的能源消耗较大,如何降低能源消耗,我们从砂轮线速度提高后对切向磨削力进行研究,磨削功率主要是对切向磨削力作功,我们对砂轮线速度和切向磨削力进行测量并分析,得出砂轮线速度和切向磨削力与磨削功率的关系,以实现节能增效,使设计的数控凸轮轴磨床更合理。数控凸轮轴磨床使用CBN砂轮磨削,砂轮修整的好坏对凸轮表面的影响是很大的。砂轮修整包括修型和修锐,对于不同的砂轮结合剂应选择合适的速比进行修锐,本文通过对不同的速比和径向进给量进行修整,通过测量所磨削的凸轮轴表面粗糙度,得出一个合理的砂轮修整速比范围,供凸轮轴加工企业进行参考。试验中发现在同一砂轮线速度下单位宽度金属切除率′与切向磨削力的比值为一定值,对磨削冷硬铸铁凸轮轴的凸轮宽度与磨削功率及砂轮线速度的影响进行定量分析,试验中得出单位宽度砂轮磨削功率,在日后的数控凸轮轴磨床设计中可根据单位宽度砂轮磨削功率和待磨削凸轮宽度对砂轮主电动机功率进行选择,以达到节能增效的目的。比磨削能随切向磨削力的增大而降低,切向磨削力越大,比磨削能值也越低。说明在切向磨削力增大的情况下金属较易被切除,这是因为随着切向磨削力的加大,金属切屑层厚度变厚的缘故;在相同的切向磨削力条件下砂轮线速度增大后比磨削能增大,砂轮线速度越高,比磨削能值也越高。说明在砂轮线速度增大的情况下金属切屑层厚度变薄。由此可知把相同体积的金属切削成较细的切屑比切削成较粗的切屑消耗的能量要多。
[Abstract]:With the attention of the state to environmental protection, the emission requirements of automobiles and internal combustion engines are more stringent, and the new requirements for the camshaft manufacturing of the valve opening and closing mechanism are also put forward, and the valve opening and closing is more accurately controlled, the accuracy of the camshaft phase angle and the accuracy of the lift error is improved. The traditional camshaft model processing method is difficult to meet the requirements. This leads to the rapid development and popularization of the CNC camshaft grinder. Most of the CNC camshaft grinder are grinded by CBN grinding wheel, the speed of the grinding wheel line is improved, the machining efficiency and the surface quality have been improved, but the new problems are also brought about, such as the effect on the tangential grinding force and the power of the main motor of the grinding wheel after the speed of the grinding wheel line is raised. CBN grinding wheel dressing, the problem of cooling and surface damage after the grinding wheel speed increases. The energy saving and environmental protection of the CNC camshaft grinder is our pursuit. The grinding energy is much larger than that of other processing methods. The total power of the camshaft grinder abroad is about 90K W, and the total power of the camshaft grinder at home has reached 120K W This makes the camshaft grinding energy consumes greatly, and how to reduce the energy consumption. We study the tangential grinding force after the speed of the grinding wheel. The grinding power is mainly done to the tangential grinding force. We measure the speed of the grinding wheel and the tangent grinding force and analyze the grinding wheel speed and the tangent grinding force. The relationship with grinding power to achieve energy efficiency and increase efficiency makes the design of the CNC camshaft grinder more reasonable. The CNC camshaft grinder is grinded with CBN grinding wheel, and the effect of grinding wheel dressing on the surface of the cam is very large. By measuring the surface roughness of the camshaft, a reasonable ratio range is obtained by measuring the surface roughness of the camshaft, and a reference is made for the convex wheel shaft processing enterprise. The ratio of the ratio of the unit width to the cutting force of the unit width at the same grinding wheel speed is found to be a certain value. The influence of the cam width on the grinding power and the grinding wheel speed of the grinding camshaft is analyzed. The grinding power of the unit width grinding wheel is obtained in the experiment. The power of the main motor of the grinding wheel can be selected according to the grinding power of the unit width grinding wheel and the width of the grinding cam in the design of the NC camshaft grinder in the future. To achieve the purpose of saving energy and increasing efficiency, the specific grinding energy decreases with the increase of tangential grinding force, the greater the tangential grinding force is, the lower the ratio of the grinding energy is, indicating that the metal is easier to be removed in the case of the increase of the tangent grinding force, because the thickness of the metal chip thickness is thickened with the increase of the tangent grinding force; the same tangential grinding force is made. Under the condition that the grinding wheel speed increases, the speed of the grinding wheel is higher and the value of the specific grinding energy is higher. It shows that the thickness of the metal chip layer becomes thinner in the case of the increase of the grinding wheel line speed. Thus, it can be seen that cutting the same volume of metal into the finer chip is more energy consuming than cutting the coarser chip.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG596

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