Analysis on the bending deformation characteristic and crack failure mechanism of thin-walled stainless-steel bellows

A novel hydrodynamic suspension micropump using centrifugal pressurization and the wedge effect

In this paper the performance of an innovative, high speed, external gear pump have been measured and verified in order to evaluate its potential application as a reliable and efficient power unit for automotive, electro-hydraulic actuated, robotized transmissions. More in detail, this particular type of volumetric machine is built with two suction and two delivery ports and is specifically designed for extremely challenging operating conditions, mainly in terms of both rotational speed and delivery pressure. First of all, the most important hydraulic and mechanical performance parameters have been measured and analyzed, over a wide range of rotational speeds, spanning between 400 and 7000 rpm, and for two different operating temperatures, respectively equal to 40 and 60 °C. In this case, with the aim to increase the consistency of the experimental measurements, two external gear pumps, with exactly the same design geometry and features, have been tested and compared, also with available data coming from the pump manufacturer. All the experimental measurements have been performed with the help of a test bench, equipped with a double Cardan joint and an overdrive, specifically tailored for running the pump at high rotational speed and applying a delivery pressure of about 45 bar, very near to a typical actuation value of a high-performance automotive robotized transmission. At the end of this experimental work, it is possible to conclude that the high speed external gear pump here tested and analyzed can be considered a reliable and effective alternative hydraulic power unit for high-performance, automotive, robotized transmissions.

Testing the performance of an innovative high speed external gear pump as a reliable hydraulic power unit for automotive robotized transmissions

In this study, an attempt is made to understand and report the effect of the temperature of working fluid on the performance of a centrifugal pump. Centrifugal pumps which are used in typical automobile applications are considered in this study and the working fluid is taken as water, the temperature ranging from 25°C to 90°C. Simulations are carried out using COMSOL software for varying pressure and temperature values of the working fluid [1]. The changes in the values of discharge, efficiencies, viscous effects of the fluid are observed and analyzed. The results showed that the pressure head and flow rate are inversely proportional which matches with the theory of centrifugal pumps. Viscous effects on pump casing are observed to have higher impact in the volute casing region at all temperatures. The pump efficiency increases initially and then decreases with respect to suction pressure, hence optimum pressure for best efficiency is obtained. However, it is observed that there are marginal changes in the efficiency at higher temperatures.

Effect of temperature of working fluid on the performance of centrifugal thermal pumps

An artificial limb is required to provide movement to manage an amputee's daily vital life. The mechanical design and simulation of an anthropomorphic multi-fingered soft prosthetic hand with 5 degrees of freedom are discussed in this study. The suggested design features 5 fingers, each of which is driven directly by two flexible hydraulic actuators (FHAs). With FEA analysis, the asymmetric flat FHA made of nitrile butadiene rubber achieved a good bending deflection of 84 degrees at 6 bar operating pressure. The simulation findings from ANSYS reveal that the bending of FHA is affected by the shape profile of the chamber and the proportion ratio of top chamber thickness to the bottom plate thickness. Myoelectric data gathered from three sensor electrodes inserted on to the surface of the forearm muscles governs the open and closure actions of fingers. With the aid of a microcontroller, a MyoWare sensor is used to plot the EMG graph. SOLIDWORKS software is used to simulate the grasping abilities of the hand while holding diverse shapes of things.

E. Sarath Krishnan

Papers

Design and Manufacture of Miniature Hydraulic Gear Pump for Bio-Medical Application