Digital rotation meter

There was developed a digital universal measuring device for the rotation frequency of various parts: a gear wheel, a splined shaft, a special disc with slots, etc. The use of a 16-digit summing electronic counter makes it possible to form a digital code up to 65536 pulses per second, which makes it possible to install it on almost any vehicle. At the same time, it has simplicity, low cost, reliability and accuracy. The design of the meter includes a signal transducer, a self-oscillating multivibrator, logic ele-ments, and an electronic summing pulse counter. The sensor of the meter is made in the form of an inductance coil with a magnetic core. The first differentiating circuit with a diode is used as a con-verter of the sensor signals, connected to a logic AND gate, which is connected by its output through a resistor to the counting input of the counter. The input of the second differentiating circuit and the second input of the logical element AND are connected in parallel with the output of the self-oscillating multivibrator, and the input for setting the zero of the counter is connected in parallel with the output of the second differentiating circuit. The self-oscillating multivibrator is symmetrical, and the resistance of its resistors and capacitors are selected in such a way that the formation of rectangular voltage pulses and pauses duration of 1 second at its output is ensured. The presence of a sixteen-bit summing electronic counter, consisting of 16 triggers and having 16 outputs and 16 light-emitting diodes, each of which is connected to one of the outputs of the counter, allows, when the meter is turned on, to receive digital codes at their output in one second, showing the speed. An example of calculating the elements of the differentiating circuit of a multivibrator is given. The experiments have confirmed the efficiency of the developed rotational speed meter.

Effects of Laser Hardening Process Parameters on Hardness Profile of 4340 Steel Spline—An Experimental Approach

This study displays the effect of laser surface hardening parameters on the hardness profile (case depth) of a splined shaft made of AISI 4340 steel. The approach is mainly based on experimental tests wherein the hardness profile of laser hardened splines is acquired using micro-hardness measurements. These results are then evaluated with statistical analysis (ANOVA) to determine the principal effect and the contributions of each parameter in the laser hardening process. Using empirical correlations, the case depth of splined shaft at tip and root of spline’s teeth is also estimated and verified with measured data. The obtained results were then used to study the sensitivity of the measured case depths according to the evolution of laser process parameters and geometrical factors. The feasibility and efficiency of the proposed approach lead to a reliable statistical model in which the hardness profile of the spline is estimated with respect to its specific geometry.

Research on Structural Analysis of Steering Based on Thermal-Structure

Stiffness and strength of the electric power steering structure were analyzed based on Catia, HyperMesh and ANSYS. Then, the influence of temperature on the stiffness of every component was also studied. The results indicate that the maximum deformations of the worm and worm wheel occur in the centre of the tooth top and their shape approximate ellipse. The deformation of the tail end of the worm-wheel shaft is large, and the limited groove area contracting the splined shaft and the steel ball bears large stress. The temperature load has some impact on the stress and deformation of components. The deformations of the components gradually enlarge with the increasing of the temperature, but the variations are not large. The stiffness and strength of steering can meet the design requirements.