On The Design of Two Rotating Mass Balancers

• Main Authors: Shiue Ming Gong, 薛明恭
• Other Authors: Professor Chiou Shen Tarng
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/74921665039065007042

碩士 === 國立成功大學 === 機械工程研究所 === 81 === The main purpose of this research is to develop the theory of applying two rotating masses to balance the Kth frequency term of the shaking force and shaking moment of spatial mecha- nisms. For the purpose, Fourier transform is applied to get frequency terms of the shaking force and shaking moment. Then for each frequency term (for example, the Kth), an equivalent system with two force vectors rotating at the same angular speed (for example, k times of that of the crank) is derived. The forces can be eliminated by equal but opposite forces exerted by counterweights mounted on the shafts rotating at the same speed, and therefore that frequency term of the shaking force and shaking moment can be balanced. The balancer with such two counterweights is called two rotating mass balancer (TRMB). When designing TRMB, two design parameters can be freely specified, so there are various arrangements for installing the balancer. It is shown that the theory developed can be specified to generate Tasi''s results[34], and furthermore it can also be specialized for designing balancers of planar mechanisms. Regarding the Kth frequency term of the shaking force of spatial mechanisms, we prove that its hodograph is a ellipse. And the formulae for determining the magnitudes and directions of its axes are also derived. For any one frequency term of the shaking force of spatial mechanisms, there is an equivalent system with two rotating force vectors whose rotation axes are parallel but opposite to each other. The analytical solution of the TRMB for eliminated them is also derived. In order to verify the correctness of the theorical works and demostrate the effectiveness of the TRMB, computer programs are developed on PC and a spatial 7R mechanism and a planar 4R mechanisms are used as the examples.