Performance Criteria for High-Speed Crank-and-Rocker Linkages—Part I: Plane Crank-and-Rocker Linkages

1979 ◽  
Vol 101 (1) ◽  
pp. 20-25 ◽  
Author(s):  
H. Funabashi ◽  
F. Freudenstein

Criteria are given for evaluating the performance and determining the dimensions of plane crank-and-rocker mechanisms suitable for operation at high speeds. In contrast to the classical procedure of simulating the acceleration pattern of the slider-crank mechanism by means of centric crank-and-rocker linkages, a family of crank-and-rocker linkages has been found, with a more nearly sinusoidal acceleration pattern, i.e., one which tends more nearly to simulate the acceleration variation of a scotch yoke. At the same time the transmission-angle variation and the ratio of minimum to maximum link lengths is controlled. A pocket-calculator procedure is described and illustrated by means of a numerical example.

1979 ◽  
Vol 101 (1) ◽  
pp. 26-31 ◽  
Author(s):  
H. Funabashi ◽  
F. Freudenstein

In Part I proportions were derived for high-speed plane crank-and-rocker mechanisms. In this part, the corresponding developments are given for spherical crank-and-rocker mechanisms. The ratios of the sine functions of the transmission angles and of the rocker accelerations—both at the dead-center positions—remain the static and dynamic performance criteria of the linkage. The results are illustrated by numerical examples, which show the influence of these ratios on the transmission-angle variation, rocker acceleration and the ratio of minimum to maximum link length.


Author(s):  
David G. Beale ◽  
Shyr Wen Lee

Abstract The nonlinear nature of high speed, flexible rod mechanisms has been previously confirmed, both experimentally and analytically. Therefore, sound control system design of flexible mechanisms must necessarily be based on nonlinear control. Active control via fuzzy logic is assessed as a means to suppress the elastic transverse bending vibration of a flexible rod of a slider crank mechanism of a slider crank mechanism. Several pairs of piezoelectric elements are used to provide the control action. Sensor output of deflection is fed to the fuzzy controller, which determines the voltage input to the actuator. A three mode approximation is utilized in the simulation study. Computer simulation shows that fuzzy control can be used to suppress bending vibrations at high speeds.


1988 ◽  
Vol 12 (3) ◽  
pp. 121-128 ◽  
Author(s):  
P.S. GREWAL ◽  
W.R. NEWCOMBE

A study is presented on the comparison of all the popular cam motions based on a refined dynamic model which takes into account the effects of cam profile errors and most of the important factors that influence the dynamic performance for a semi-rigid follower cam system. A stochastic model is developed to simulate the input signal resulting from the cam motion, including the deviations due to profile errors. The performance criteria comprise the vibrational response at the follower and the dynamic characteristics at the cam. It has been established that, at high speeds, it is not the vibrational behaviour, but the follower tendency to jump and the maximum contact force and cam torque values which determine the dynamic performance. The Modified-Sine, Simple Harmonic and 3-4-5 Polynomial motions have been shown to exhibit superior high speed performance compared to that of the popular Cycloidal and Modified Trapezoidal motions. Higher-order Polynomial motions give very poor performance at high speeds.


TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.


Alloy Digest ◽  
1980 ◽  
Vol 29 (8) ◽  

Abstract RED CUT COBALT steel is made by adding 5% cobalt to the conventional 18% tungsten -4% chromium-1% vanadium high-speed steel. Cobalt increases hot or red hardness and thus enables the tool to maintain a higher hardness at elevated temperatures. This steel is best adapted for hogging cuts or where the temperature of the cutting point of the tool in increased greatly. It is well adapted for tools to be used for reaming cast-iron engine cylinders, turning alloy steel or cast iron and cutting nonferrous alloys at high speeds. This datasheet provides information on composition, physical properties, and hardness as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-367. Producer or source: Teledyne Vasco.


Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.


1948 ◽  
Vol 15 (3) ◽  
pp. 248-255
Author(s):  
E. T. Habib

Abstract In mechanical gages used to measure the pressure from an underwater explosion, small copper cylinders are compressed at high speeds. This paper describes the test apparatus designed for the dynamic calibration of these cylinders, presents the results obtained with this apparatus, and compares these results with those obtained by other experimenters.


2001 ◽  
Vol 124 (2) ◽  
pp. 398-405 ◽  
Author(s):  
S. Yoshimoto ◽  
S. Oshima ◽  
S. Danbara ◽  
T. Shitara

In this paper, the stability of water-lubricated, hydrostatic, conical bearings with spiral grooves for high-speed spindles is investigated theoretically and experimentally. In these bearing types, pressurized water is first fed to the inside of the rotating shaft and then introduced into spiral grooves through feeding holes located at one end of each spiral groove. Therefore, water pressure is increased due to the effect of the centrifugal force at the outlets of the feeding holes, which results from shaft rotation. In addition, water pressure is also increased by the viscous pumping effect of the spiral grooves. The stability of the proposed bearing is theoretically predicted using the perturbation method, and calculated results are compared with experimental results. It was consequently found that the proposed bearing is very stable at high speeds and theoretical predictions show good agreement with experimental data.


2020 ◽  
Vol 318 ◽  
pp. 01004
Author(s):  
Miroslav Blatnický ◽  
Ján Dižo

In this article, authors focus on the design and construction of a real prototype of an engine mechanism with rotating cylinders and its using mainly in piston combustion engines. It is assumed, that the normal force of a piston will be completely eliminated, because the swing angle of a connecting rod will equal to zero during the whole working cycle, since the connecting arm of the piston moves just the cylinder axis. It will by allowed by the conceptual design of the mechanism presented in this article. As rotating blocks of cylinders concurrently act as a flywheel, it is proposed, that in this way there is possible to save the mass of additional flywheels. Moreover, liquid cooling system is not necessary, because the rotating cylinders sufficiently transfer heat to ambient air. In addition, the output of torque will be reached without necessity of gear transmission, which results to decreasing of needs of mechanism lubrication. Other advance of the designed mechanism are two outputs. The first output is low-speed and it goes out from rotating cylinders, i. e. from the slider-crank mechanism with revolutions n1. The other output is high-speed, from the crankshaft with revolutions n2. Because of more favourable properties of the mechanism, authors have decided to create a real device to confirm all mentioned advantages of the mechanism by the suitable way.


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