Showing papers on "Pressure angle published in 1983"

Polymer melt rheology with a slit die

Abstract: A piston driven high pressure slit die rheometer with three pressure holes along the die and one in the barrel was used to investigate viscosity, entrance and exit pressure losses, and pressure coefficient of viscosity of a LDPE melt. Hydrostatic calibration of melt pressure transducers can be performed in the rheometer. The slit die results are compared with measurements on circular dies assuming linear and parabolic pressure profiles in both cases. A simplified conversion from apparent to true viscosity, applicable for single point measurements, has been used. In spite of the different symmetries the Bagley correction from the linear pressure profile of circular dies was found to be equal to the sum of exit and entrance pressure losses in the slit. The magnitude and sign of the exit pressure loss depend on the type of pressure profile used. The influence of a pressure dependent viscosity and a temperature gradient along the die on the curvature of the pressure profile is discussed. To directly investigate the effect of pressure the pressure level at constant flow rate was increased stepwise by means of a valve attached to the exit of the slit die.

Effects of Contact Ratio and Profile Correction on Gear Rotational Vibration

Abstract: In this paper gear performance on vibration is discussed in a wide range of contact ratios from 1.26 to 2.46 using a developed simulator. And tooth profile correction is investigated in relation to pressure angle error. The simulation results are verified through good agreement with results of dynamic meshing tests. From this investigation the effects of contact ratio and profile correction are clarified.

Tooth Profile Analysis of Circular-Cut, Spiral-Bevel Gears

Abstract: An analysis of tooth profile changes in the transverse plane of circular-cut, spiral-bevel crown gears is presented. The analysis assumes a straight-line profile in the mid-transverse plane. The profile variation along the centerline is determined by using expressions for the variation of the spiral angle along the tooth centerline, together with the profile description at the mid-transverse plane. It is shown that the tooth surface is a hyperboloid and that significant variations in the pressure angle are possible.

Flexible power transmission belt and power transmission system

Abstract: A flexible power transmission belt having a plurality of teeth (13) each of which has a pair of arcuate convex flank portions (21, 22) which in longitudinal cross-section closely approximate to an arc of a circle. Each tooth exhibits a height (H) to width (W) relationship within a predetermined range, and the arcuate flanks each have a pressure angle (a) within a predetermined range. The belt is preferably used in combination with a toothed pulley whose teeth are substantially conjugate to the belt teeth and whose cavities between the teeth have a height to width relationship within another predetermined range and have concave flanks exhibiting a pressure angle in still another predetermined range, said belt tooth width being approximately 0.98 of the pulley cavity width so as to provide a high torque positive drive power transmission system having very low backlash.

Barrel type built-up gear hob

Abstract: PURPOSE:To form a tooth profile, by rotating a spherical hob a turn as centering on the hob spindle center, while making a tooth into a state of being slipped as far as a portion for a pitch, as rotating the spherical hob in succession, and letting it engage an internal gear blank rotating synchronously with this. CONSTITUTION:In case of a barrel type built-up gear hob for forming an internal gear, as a result of finding a condition to materialize it as a built-up gear hob in the case where a relieving tooth profile 22 is formed out of a tooth profile 21 of a cutting edge face, it will do simply that a direction of interlocking for tooth profile relieving merely takes vartical with a hob spindle center 23. Next, a pitch circle diameter of the internal gear to be machined and a basic circle diameter are set down to dm and dg each, while a tooth top circle diameter of the internal gear to be machined is set so as to become more than {(dm- Dm) sin alpha-dg } when the pitch circle diameter of a virtual gear and its intermeshing pressure angle are set down to Dm and alpha each. Thus, a tooth profile can be formed in a state of being excellent in accuracy.

Tooth Fillet Stresses of Gear with Thin Rim : 3rd report, Examination of Approximation Formulae for Gear Tooth Fillet Stresses

Abstract: To confirm the reliability of the approximation formulae for tooth fillet stresses of thin-rimmed gears (5) and to reveal the influences of many factors on the stress value, the tooth fillet and root stresses of a thin-rimmed gear calculated by the approximation formulae have been compared with the FEM calculated values : The influences of the radius of curvature of tooth fillet, of the width of the bottom of tooth space, of the pressure angle and of the loading position on tooth flank on the tooth fillet and root stress distribution for the case of a rack have been investigated and the scope of validity for the approximation formulae has been indicated. The calculation of the fillet and rootstresses for the loaded and unloaded teeth under a single and double tooth pair meshing was worked out by use of the approximation formulae, and the accuracy of calculation has been confirmed to be as good as that of FEM.

Rotary positive-displacement fluid-machines

Abstract: The invention concerns helical- or screw-type driving and driven rotors having lands and intervening grooves for coacting engagement, within a housing of a machine, such as a gas compressor or expander, the rotors having improved, more efficient, profiles. The profiles are defined with contiguous elliptic and involute sections to improve the pressure angle, and the profiles are configured to define rotor-to-rotor sealing surfaces in closure of a compressed gas pocket in which, the pocket gas pressure always urges or torques the driven rotor in the positive or forward-rotary direction.

Helical type rotor

Abstract: The invention concerns helical- or screw-type driving and driven rotors having lands and intervening grooves for coacting engagement, within a housing of a machine, such as a gas compressor or expander, the rotors having improved, more efficient, profiles. The profiles are defined with contiguous elliptic and involute sections to improve the pressure angle, and the profiles are configured to define rotor-to-rotor sealing surfaces in closure of a compressed gas pocket in which, the pocket gas pressure always urges or torques the driven rotor in the positive or forward-rotary direction.

A method for static and dynamic load analysis of standard and modified spur gears

Abstract: The mesh stiffness and dynamic load characteristics for several cases of the Normal Contract Ratio and High Contact ratio gearing. The considered contact ratios were grouped in the general range of 1.7,2.0, and 2.3. The HCR gearing is defined by contact ratios equal to or greater than 2.0. The HCR gearing is represented by a group of small pressure angle, fine pitch, and long addendum gearing.

Geometrical analysis of circular-cut spiral bevel gears

Abstract: Geometrical studies of circular cut spiral bevel gears are reported. Tooth profile changes heel to toe are studied in the transverse plane. Pressure angle changes are determined. The radiuses of curvature of the tooth surfaces generated by various cutter profiles are also determined. The consequences of cutter profile changes are explored. Crown gears are emphasized and the implications for conical gears are discussed.

The Optimal Design of Standard Gearsets

Abstract: A design procedure for sizing standard involute spur gearsets is presented. The procedure is applied to find the optimal design for two examples - an external gear mesh with a ratio of 5:1 and an internal gear mesh with a ratio of 5:1. In the procedure, the gear mesh is designed to minimize the center distance for a given gear ratio, pressure angle, pinion torque, and allowable tooth strengths. From the methodology presented, a design space may be formulated for either external gear contact or for internal contact. The design space includes kinematics considerations of involute interference, tip fouling, and contact ratio. Also included are design constraints based on bending fatigue in the pinion fillet and Hertzian contact pressure in the full load region and at the gear tip where scoring is possible. This design space is two dimensional, giving the gear mesh center distance as a function of diametral pitch and the number of pinion teeth. The constraint equations were identified for kinematic interference, fillet bending fatigue, pitting fatigue, and scoring pressure, which define the optimal design space for a given gear design. The locus of equal size optimum designs was identified as the straight line through the origin which has the least slope in the design region.

Effect of Top-Relief and Rake Angles on the Gear Shaping Cutter Profile

Abstract: Gear shaping cutters are provided with top-relief and rake angles. As a result of this, the profile representing the cutting edge is modified. This paper deals with the method of obtaining the effective profile on the rack-type and pinion-type cutters for spur gears. Analysis of the effective profile shows that the effective profile of the rack-type cutter is actually a straight-sided tooth form with different pressure angle and tooth thickness at the reference (pitch) line. In the case of the pinion-type cutter, tooth thinning takes place and the effective profile could not be identified with any involute form.This paper also deals with the methods of correcting the cutter profile form so that profile close to the theoretical form can be obtained on grinding the rake face. This approach would be quite useful to the designers and manufacturers of the shaping cutters.