scholarly journals Metathesis by partner interchange in σ‐bond ligands: expanding applications of the σ‐CAM mechanism

Author(s):  
Robin N. Perutz ◽  
Sylviane Sabo-Etienne ◽  
Andrew S. Weller
Keyword(s):  
2015 ◽  
Vol 138 (2) ◽  
Author(s):  
W. Wu ◽  
J. Wang ◽  
C. H. Venner

A high-order polynomial gas distribution cam mechanism is investigated theoretically from the viewpoint of thermal elastohydrodynamic lubrication (EHL). First, a cam with a larger base circle radius is employed, which results in slide–roll ratio 2.0 < S < 9.0 when the two surfaces move oppositely. The pressure, film thickness, and temperature profiles at a number of angular positions of the cam are presented, together with the isothermal results. The comparison between thermal and isothermal oil characteristics is also shown. It is revealed that the isothermal analysis partly overestimates the actual film thickness and it also misses some essential local phenomena. Second, a cam with a smaller base circle radius is studied, which leads to drastic variations in the slide–roll ratio which encounters four times’ occurrences of infinity in one working period. The pressure, film thickness, and temperature profiles at some angular cam positions together with the oil characteristics are given, showing much dramatic variations. A very small film thickness is observed at the contact of the tappet with the start of the cam basic segment, which suggests a possible risk of direct contact of both surfaces.


2012 ◽  
Vol 184-185 ◽  
pp. 301-306
Author(s):  
Rong Fu Lin ◽  
Yong Chang

This paper proposes the conditions of no-undercutting and contact-retaining of the disc cam mechanism with negative radius roller follower. Then, it presents the contact stress expression based on the mechanical analysis. In addition, the effects of different parameters on the force and contact stress are analysed. The results show that the contact stress can be reduced by designing the suitable parameters of the cam.


2002 ◽  
Vol 68 (668) ◽  
pp. 1191-1197
Author(s):  
Masatoshi HIKIZU ◽  
Hiroaki SEKI ◽  
Yoshitsugu KAMIYA ◽  
Hiroshi TACHIYA ◽  
Hisanao NOMURA

Author(s):  
M Nishioka ◽  
T Nishimura

Parallel cam mechanisms have been studied in different ways. In this paper, a parametric formulation which can cover every configuration of the parallel cam mechanism is derived. As a result of parametric analysis, a new, last mechanism was found. This cam is essentially an internal cam mechanism. Based on the assumption of an equally distributed roller follower, the basic configurations of the mechanism are derived from both the pressure angle and the undercutting constraints. As a result, the possible number of rollers per spider plate is two. Thus the feasible area of the design parameters of the mechanisms are obtained. The advantages of the mechanism over the conventional parallel mechanism are the saving of space and a larger angular stroke of output.


2012 ◽  
Vol 184-185 ◽  
pp. 384-388
Author(s):  
Bing Tian Gao

In order to realize the technical performance of high speed, high precision, high stability and high reliability for conjugated indexing mechanism with periodic intermittent rotary motion, a two cams structure has been designed, and its geometry size and profile curve was carefully determined. Also the calculation formula of the contour curve for CAM was deduced. Research achievement has been applied to new equipment of enterprise development, the working performance is stable and reliable, the production efficiency raised by 30% compared to the domestic industry. The mechanism has characteristics of simplified structure, improved transmission performance and low cost.


2011 ◽  
Vol 86 ◽  
pp. 496-499 ◽  
Author(s):  
Nian Fu Xu ◽  
Feng Xu ◽  
Wei He

Because of the design and manufacture of the globoidal indexing cam mechanism is very difficult, this paper developed a globoidal indexing cam CAD/CAM system by using Pro/ Engineer’s further development module Pro/Toolkit, which can simplify the process of designing the globoidal indexing cam. The main idea is that designing cam by parameters and generating the data points of the indexing cam automatically by the computer.


Author(s):  
Akane Ishizuka ◽  
Narimasa Ueda ◽  
Yoshitaka Morimoto ◽  
Akio Hayashi ◽  
Yoshiyuki Kaneko ◽  
...  

Abstract Since shifting to electric vehicles as a countermeasure against global warming is not always easy to complete, the hybrid car has been considered as another possible solution. However, based on the calculation of total CO2 emissions, all hybrid cars which will constitute 90% of all cars are expected to be equipped with an internal combustion engine even after 2030. Therefore, further efficiency improvement of the internal combustion engine is necessary. One of the key factors is the variable valve timing and variable lift with the 3D cam mechanism. Since conventional technology uses a complicated link mechanism and servo motor control, this leads a problem to set into small cars or motorcycles because they cannot afford to install the variable valve timing and variable lift with cam mechanism. To solve this problem, a cam shape with a three-dimensional curved surface has been proposed. In order to create this shape, the machining method for non-axisymmetric curved surface turning (NACS-Turning) is required. To build the new system, our research group has proposed a new machining method using a driven type rotary tool and a linear motor driven moving table to enable to achieve NACS-Turning. In this new system, a new tool rotation axis (B axis) is adopted to synchronize its rotational position with the rotational position of the spindle (C axis) holding the workpiece, the X1-, X2-, and Z-Axis positions in total. In this paper, the new hardware configuration is proposed to overcome the present machining accuracy.


2019 ◽  
Vol 132 ◽  
pp. 1-12 ◽  
Author(s):  
Yuhu Yang ◽  
Jianyong Wang ◽  
Shicai Zhou ◽  
Tian Huang
Keyword(s):  

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