Pressure angle

About: Pressure angle is a research topic. Over the lifetime, 1373 publications have been published within this topic receiving 10245 citations. The topic is also known as: angle of obliquity.

Flow characteristics of external gear pumps considering trapped volume

Abstract: This article investigates the volume change law of trapped fluid in the meshing process and the flow characteristics of external gear pumps under the following two cases: the pump design with and without relief groove. In this study, a mathematical modeling of gear pairs is deduced based on the meshing theory and a complete set of mathematical equations of tooth profile, and the flow rate equation is derived based on law of conservation of mass across the changing boundaries of a control volume. During the process, the function of the pump displacement is established, which is formed by two parts: tooth space volume and trapped volume. In addition, using a control volume approach, the trapped volume and flow rate characteristics of the pump under different design parameters of gears are discussed. The results show that the curve of trapped volume is similar to a parabola and the pump designed with a large number of teeth, module, and pressure angle easily obtained good flow rate characteristics under the ...

Modeling Parametric Vibration of Multistage Gear Systems as a Tool for Design Optimization

Abstract: This work presents a numerical model developed to simulate the dynamics and vibrations of a multistage tractor gearbox. The effect of time varying mesh stiffness, time varying frictional torque on the gear teeth, lateral and torsional flexibility of the shafts and flexibility of the bearings were included in the model. The model was developed by using the Lagrangian method, and it was applied to study the effect of three design variables on the vibration and stress levels on the gears. The first design variable, module, had little effect on the vibration levels but a higher module resulted to higher bending stress levels. The second design variable, pressure angle, had little effect on the vibration levels, but had a strong effect on the stress levels on the pinion of a high reduction ratio gear pair. A pressure angle of 25 o resulted to lower stress levels for a pinion with 14 teeth than a pressure angle of 20 o . The third design variable, contact ratio, had a very strong effect on both the vibration levels and bending stress levels. Increasing the contact ratio to 2.0 reduced both the vibration levels and bending stress levels significantly. For the gear train design used in this study, a module of 2.5 and contact ratio of 2.0 for the various meshes was found to yield the best combination of low vibration levels and low bending stresses. The model can therefore be used as a tool for obtaining the optimum gear design parameters for a given multistage spur gear train. Keywords—bending stress levels, frictional torque, gear design parameters, mesh stiffness, multistage gear train, vibration levels. NOMENCLATURE

Precise design and profile modification method for asymmetric gear

Abstract: The invention relates to a precise design and profile modification method for an asymmetric gear. The method comprises the following steps that S1, the tooth profile equation of a rack tool is obtained according to the structure of the rack tool; S2, coordinate transformation is carried out on the tooth profile equation of the rack tool according to the movement rule of the rack tool to obtain a rack tool equation under a gear coordinate system; S3, a meshing equation is obtained according to the meshing rule of the rack tool and the gear; S4, the tooth profile equation of the asymmetric gear is determined according to the rack tool equation and the meshing equation; S5, three-dimensional modeling is carried out according to tooth profile data. The profile modification method directly carrying out pressure angle profile modification on the rack tool is disclosed, the tool after the profile modification can directly carry out machining to obtain the formed gear having the involute modified, the gear machining efficiency is improved, and the obtained formed gear through the profile modification is simple and practical.

Base curves of involute cylindrical gears via Aronhold’s first theorem

Abstract: The subject of this paper is the synthesis of the base curves of involute cylindrical gears, for uniform and non-uniform transmission ratio, by means of Aronhold’s first theorem and the return circle. The base curves can be generated in several ways, as reported in the literature, but this approach comes from the kinematics fundamentals; it is, thus, more straightforward than the alternatives for the case of non-uniform transmission ratio, which leads to non-circular gears. The base curves of circular and non-circular gears are obtained by intersecting, at each pitch point, the corresponding return circle with the line of action for a given pressure angle. This is possible for involute cylindrical gears since the tooth profile of the rack is represented by a line, and the conjugate profiles of the two meshing gears can be generated by its envelope.