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.

Probabilistic Analysis of MEMS Asymmetric Gear Tooth

Abstract: Currently, there is an increased interest in the application of microelectromechanical system (MEMS) gear drives. Additionally, requirements for transmitted power and related reliability issues have increased. Reliability issues often occur due to uncertainties of material, geometry, and loading conditions of the MEMS gears. Asymmetric gear teeth are used to improve the performance of gears by increasing the load capacity or by reducing vibrations. In this paper, asymmetric gear teeth are proposed for MEMS applications. The objective of this research is to investigate the feasibility of applying asymmetric gears for MEMS devices while accounting for uncertainty. The Weibull failure theory was applied to four different MEMS gear configurations. The following analyses were carried out in this research: (i) for the calculation of root stress, four different asymmetric gears were used; (ii) for the calculation of the probability of failure, the Weibull failure theory formulization was used, and (iii) the efficacy of the various asymmetric tooth configurations was discussed. Specifically, the probability of failure of the asymmetric gear was extracted for various parameters. The parameters considered included pressure angle, tooth height, and contact ratio. The efficacy of using asymmetric gear teeth was shown in this study.

Indentation plasticity of amorphous and partially crystallized metallic glasses

Abstract: Plastic behavior at room temperature of amorphous, partially crystallized, and fully crystallized Zr41.25Ti13.75Cu12.5Ni10Be22.5 Vitreloy 1 samples was investigated using instrumented indentation. Residual imprints were imaged using atomic force microscopy (AFM). Young’s modulus and hardness were estimated using the contact area derived from AFM imaging. It has been shown that the postmortem area measurement is useful to take into account the pileup effect. Indentation experiments performed with a conical tip were associated with parametric two-dimensional axisymmetric finite element modeling using a pressure-sensitive yield criterion. A two-parameter reverse analysis algorithm was used to probe both yield stress and pressure angle. Results showed that the amorphous alloy exhibits a yield stress and pressure angle in good agreement with literature and compressive tests, and that crystallization affects the pressure angle.

Tertiary negative-deviation flexing contact type gear drive of non-profile-shifted tooth profile

Abstract: In a cup-shaped flexing contact gear (1), both a rigid internal gear (2) and a flexible external gear (3) are made to be non-profile-shifted spur gears, an opening (3a) of the flexible external gear (3) is set in a state of negative deviation wherein a deflection of the opening is lower in value than a normal deflection; a moving locus is obtained through rack approximation of teeth of the external gear to the internal gear at respective sections of rotation of tooth trace of the flexible external gear (3), an envelope (e) is obtained by overlapping the moving locus on one of sections of rotation, another moving locus is obtained in a section of rotation at the end portion of tooth trace on the side of a diaphragm or in the vicinity of the outside of the end portion and is smoothly connected to the envelope to thereby obtain a composite curve (L). A curve (FE) is obtained by similarity transforming at a reduction ratio of 1/2 a portion from a starting point (A) of the envelope (e) to a terminating point (E) thereof corresponding to two times the working depth in the direction of the depth from an apex of a moving locus (l o) when deviation is 0, using the terminating point as an original point, and this curve is made to be each of main portions of convex tooth profiles at tooth faces of the both gears (2, 3). Further, a composite curve (MFE) including a straight line (MF) having a limited pressure angle (α M ) associated with a deflection value of the opening inserted in the vicinity of a datum point (M) of tooth profile and a transient curve smoothly connecting the straight line to the main portion of the convex tooth profile is made to be each of tooth profiles at the tooth faces of the both gears.