带有阶梯沟槽结构音叉型石英晶体谐振器设计研究

为了解决表面贴装器件(SMD)型压电石英音叉晶体的振动阻抗过大的问题,提出了一种带有阶梯沟槽结构的Z切压电石英音叉晶体谐振器。首先,从振动原理上结合压电石英晶体各向异性材料因腐蚀工艺导致结构的不对称性解释阻抗过大的机理;然后,提出一种新结构弥补因腐蚀工艺带来音叉晶体结构不对称的问题。基于有限元仿真计算出音叉晶体谐振器的振动分布情况,通过仿真分析发现新型结构有效降低音叉双叉振梁面内弯曲的不对称性,改善了音叉晶体谐振器的振动特性,降低了器件的阻抗。

Pipe reduction of miniature inner grooved copper tubes through rotary swaging process

A rotary swaging machine was applied to fabricating pipe reduction for miniature inner grooved copper tube （MIGCT） heat pipes. Compared with conventional swaging method, the axial feed of the designed rotary swaging machine was reached by a constant pushing force. The deformation of grooves in pipe reduced section during rotary swaging was analyzed. The shrinkage and extensibility of pipe reduction were measured and calculated. Furthermore, four aspects, including outer diameter, surface roughness, extensibility and processing time of pipe reduction, which were influenced by the pushing force, were considered. The results show that the tube wall thickness increases gradually along the z-axis at sinking section. However, the outer diameters, surface roughness and micro-cracks at reduced section tend to decrease along the z-axis. Besides, the effect of variation in the pushing force on the extensibility is limited while an increase in the pushing force results in a decrease of surface roughness. Therefore, a large pushing force within the limit is beneficial to pipe reduction manufacturing during rotary swaging process.

出口国外大型水泥磨机衬板的研制

一仓沟槽阶梯衬板主要承受高硬度铁球和高硬物料高应力冲击凿削,要求具有足够的冲击韧性和较高的硬度。选择合金含量较高的中碳铬钼镍合金钢作为衬板的材质,确保热处理后衬板硬度HRC≥46,冲击韧性a_k≥25J/cm^2。二仓锥形分级衬板主要承受高硬度铁球和高硬物料低应力摩擦切削,要求具有一定的冲击韧性和较高的硬度。选择中碳铬钼合金钢作为衬板的材质,确保热处理后衬板硬度HRC≥50,冲击韧性a_k≥10J/cm^2。为避免产生皱皮、夹渣、气孔等铸造缺陷,采用先烧后浇消失模铸造工艺进行制作,获得表面光洁和内部致密的衬板。

采用先烧后浇消失模铸造工艺制作出口国外大型水泥磨机衬板

一仓沟槽阶梯衬板主要承受高硬度铁球和高硬物料高应力冲击凿削,要求具有足够的冲击韧性和较高的硬度。选择合金含量较高的中碳铬钼镍合金钢作为衬板的材质,确保热处理后衬板硬度HRC≥46,冲击韧性ak≥25J/cm^2。二仓锥形分级衬板主要承受高硬度铁球和高硬物料低应力摩擦切削,要求具有一定的冲击韧性和较高的硬度。选择中碳铬钼合金钢作为衬板的材质,确保热处理后衬板硬度HRC≥50,冲击韧性ak≥10J/cm^2。为避免产生皱皮、夹渣、气孔等铸造缺陷,采用先烧后浇消失模铸造工艺进行制作,获得表面光洁和内部致密的衬板。