预制体缝合针稳定性分析及插刺机构改进设计

针对70 mm厚预制体正交叠层机织碳布缝合装置在缝合碳布过程中易出现超长缝合针压杆失稳问题,在对缝合针进行稳定性分析的基础上,设计了增大其失稳临界力的改进机构。该机构由抱针凸轮、抱针杆及抱针块等组成,设计的理论依据是通过抱针块增加缝合针中段约束点,减小缝合针悬臂长度,同时利用抱针凸轮控制抱针块在缝合针刺入叠层碳布后的位置,确保抱针块始终处于使缝合针失稳临界力最大时的位置。抱针凸轮轮廓曲线根据抱针块位置变化轨迹由MatLab生成并优化,抱针块相对于缝合针的位置变化轨迹依据欧拉公式确定。为验证改进后的单针插刺机构原理可行性,进行了正交叠层机织碳布插刺实验,结果表明其原理可行,工作可靠。

Stability analysis of suture needle of prefabricated parts and improvement of inserting mechanism

Aiming at the problem of easy occurrence of pressure bar destabilization of the long sewing needle during the sewing of the carbon cloth by orthogonal-crossed woven carbon cloth sewing device for the 70 mm-thick prefabricate, based on the analysis of the stability of the sewing needle, a mechanism was designed to increase the destabilization critical force. The mechanism is composed of a needle-holding cam, a needle-holding pole and a needle-holding block. The theoretical basis for the design is to reduce the cantilever length of the sewing needle by increasing the constraint point of the middle part of the needle by the needle-holding block, and to ensure the block always in the position where the destabilization critical force of the sewing needle is maximized by the limitation of the needle-holding cam, after the sewing needle penetrates into the carbon cloth. The contour of the cam is generated and optimized by MatLab according to the changing track of the position of the needle-holding block, which is determined according to the Euler formula. For verifying the feasibility of this improved single needle insertion mechanism, an insertion experiment of orthogonal-crossed woven carbon cloth was performed. The results showed that the principle is feasible and the working process is reliable.