| Linkage mechanism, seen as the theoretical structure model of all other basic mechanisms has some advantages in mechanical field: a). Easy manufacturing and high loading ability of pair element in lower pair structure; b). Diversities in movement pattern and regularity; c) various movement outputs of the same mechanical part in plane closed chain mechanism in terms of patterns and regularities; d). Easy adjustment and control in movement regularity; e). Flexible set-up of free degree. But some of these properties such as multiple output, easy adjustment and control and various free-degree sets still remain incompletely understood while other properties have been well known and extensively applied. In addition, drawbacks such as uncertain constraint and overconstraint of plane closed chain mechanisms, unknown solutions to synthesis equations of mechanism criterions and unstable movement of mechanism parts have been recorded. Impulse stepless speed regulator is a promising and potential mechanical stepless speed regulator. Its key part, impulse generator mechanism is the very linkage mechanism. To achieve high efficiency, adjustable rotating speed, high stability, various impulse output and simple structure as well as high-speed transmission, one is required to employ the advantages of linkage mechanism and overcome its weaknesses. The objective of this Ph.D. thesis was to study the linkage mechanism from the theoretical and methodological point of view in order to achieve high efficiency and stability. (1)A novel transmission mechanism called full turning-pair type of double output impulse generator mechanism was established, possessing the intrinsic properties of linkage mechanism and simplified systematic structure. Some drawbacks commonly seen in current impulse generator mechanisms, such as low efficiency, uncontinuity of driving force and higher impact were permanently overcome. In light of the requirements on the functional properties of impulse stepless speed regulator, a possibility that the six-link movement pair is used as a transmission mechanism was discussed by applying the synthesis principle of mechanism structure. In addition, focusing on the double output impulse generator mechanisms, their structural properties and selection programs for different models were studied in detail and the characteristics of some basicdynamics and motor mechanism were further analyzed.(2)The synthesis principle and methodology of identical-grade four link mechanism were proposed so that the functional generator mechanism with six-link and double output could meet the demands for the ratio of transmission to motion. The problems regarding the initial criterion synthesis were solved and analysis for basic structure and motor natures of the six-link mechanism was accomplished. (3)To control and improve the properties of mechanism dynamics, a synthetical parameter model of high-grade motion was created for three-grade functional generator mechanism with double output. Meanwhile, the optimization about motion and dynamics of the mechanism was carried out by employing homotopy-continuation method. (4)A novel differential and double brake-block overrunning speed clutch was developed. Its working mechanism was detailed based on the characterization of its structure and dynamics and the principle determining the structural parameters was probed. Analysis results indicated that this new clutch was self-adjustable and self-adaptable and differed from the conventional overrunning speed clutch in terms of motoring principle. Moreover, the principle and function of the new clutch were confirmed by in-house experiment. (5)To obtain high efficiency and high stability, the automatic adjusting function of double output impulse generator mechanism was innovated. The method and regulation to determine and select all possible variations of motion pairs were established which were applicable for the process when non free-degree element group in plane closed chain mechanism approached a zero over-co...
|
PDF Full Text Request