Showing papers on "Pressure angle published in 2016"

Evaluation of load capacity of gears with an asymmetric tooth profile

Abstract: An ISO standard tooth profile has a symmetric pressure angle of 20°. However, the load capacity can be increased with respect to bending and contact pressure by increasing the pressure angle on the meshing side of an asymmetric tooth. Accordingly, we analyzed the torque transmission capacity of asymmetric gears with various pressure angles. We calculated the deflection and bending stress of teeth by the finite element method and found the root stress taking into account the load-sharing ratio. Hertzian contact stress was calculated with respect to contact pressure. Normal vector load was converted into a torque, and torque capacity was evaluated when the stress reached the allowable stress for each case. Reduced bending stress because of an increase in tooth thickness and decreased transmission torque because of a reduction in the base circle radius work together to maximize the load capacity for bending at a pressure angle of around 30°. Maximum load capacity with respect to contact pressure is achieved when the pressure angle is made 45° by increasing the radius of the contact surface. Both strength with respect to bending and contact pressure are found, and the torque transmission capacity of the gear is determined by the lower value of the two. For low-strength materials such as flame-hardened steel, damage due to contact pressure is expected for all forms of gears and the greatest torque capacity was at a pressure angle of 45°. In the case of assuming 800 Hv and an inclusion size $$ \sqrt{\boldsymbol{A}}=50 $$ μm for a high-strength material, the greatest torque transmission capacity is obtained at a pressure angle of 30°. In the case of assuming a moderate-strength material such as case-hardened steel, an optimal form exists at which strength with respect to bending and strength with respect to contact pressure are equal.

Direct Gear Design for Asymmetric Tooth Gears

Abstract: In many gear drives, the tooth load on one flank is significantly higher and is applied for longer periods of time than for the opposite one. An asymmetric tooth shape reflects this functional difference. Design intent of asymmetric gear teeth is to improve performance of the primary drive profiles at the expense of the performance off the opposite coast profiles. The coast profiles are unloaded or lightly loaded during a relatively short work period. Asymmetric tooth profiles also make it possible simultaneously to increase the contact ratio and operating pressure angle beyond the conventional gear limits. The main advantage of asymmetric gears is contact stress reduction on the drive flanks, resulting in higher torque density (load capacity per gear size). The paper presents an application of the Direct Gear Design® method to asymmetric tooth gears. This is an alternative approach to traditional design of involute gears, separating gear geometry definition from the generating (tooling) rack to maximize gear drive performance. The paper describes asymmetric tooth and gear mesh characteristics, limits of asymmetric tooth gearing, tooth geometry optimization, analytical and experimental comparison of symmetric and asymmetric tooth gears, and implementation of gears with asymmetric teeth.

Profile design for the cylinder of a double-acting rotary vane compressor:

Abstract: Inner wall profile of the cylinder in a rotary vane compressor (RVC), which influences the motion characteristics of vanes, suction volume, friction characteristic, etc., plays an important role in the performance of the compressor. This work mainly aims at the profile design of a new cylinder for a double-acting RVC with harmonic profile cylinder on the basis of not changing integrate size. According to the relation between cylinder profile and vane motion characteristics, a method for the cylinder profile design is proposed in this paper. With an assumed vane motion, equations of the cylinder profile, cell volume of the compressor as well as pressure angles between vanes and cylinder inner wall are constructed preliminarily. And then through adjusting parameters and optimization with an independently developed procedure, a new cylinder with the so-called combined profile is obtained. Theoretical analysis of the cell volume variations and the pressure angles between vanes and cylinder are conducted. The ...

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 ...

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.

Active correction of the tilt angle of the surface plane with respect to the rotation axis during azimuthal scan

Abstract: A procedure to measure the residual tilt angle ττ between a flat surface and the azimuthal rotation axis of the sample holder is described. When the incidence angle θθ and readout of the azimuthal angle ϕϕ are controlled by motors, an active compensation mechanism can be implemented to reduce the effect of the tilt angle during azimuthal motion. After this correction, the effective angle of incidence is kept fixed, and only a small residual oscillation of the scattering plane remains.

Spur gear design: some new perspectives

Abstract: New perspectives such as harmonic mean, contact patch as translating third body, contact form factor, and service load factor are introduced in spur gear design. The harmonic mean rule characterizes the physical and geometric properties of the contact patch. The contact patch is construed as a body in translation during gear teeth engagement. The contact form factor may be used to compare the load capability of different pressure angle standards. The service load factor captures the influence of different conventional rated load modification factors. Gear design analysis is separated into design sizing and design verification tasks. Design sizing and design verification formulas are formulated and presented in simplified forms for the Hertz contact and the Lewis root bending stresses. Three design Examples are presented through which it is demonstrated that results from the contact and root bending stress capacity models compare very favorably with American Gear Manufacturers Association (AGMA) results. The worst differences in the results are 5.23% for contact stress in design Example 2 and -6.59% for root bending stress for design Example 1. In design Example 3, it is shown that using pinion teeth number higher than 17 or 18 can leads to overall size reduction of gearset. This is important because of possible manufacturing cost reduction and higher mesh efficiency. Comparison of proposed approximations for mesh overload, internal overload and service load factors for design sizing and design verification tasks yielded very close results. The highest variance in the three design examples between proposed approximated and AGMA values of these parameters is -5.32%, indicating a slightly higher or conservative value for design sizing. Due to the very favorable results in comparison with AGMA values, the design approach appears to be an acceptable one in the preliminary design of spur gears because of simplicity and transparency.

External high-order multistage modified elliptical helical gears and design procedure of their gear pairs:

Abstract: In view of the limited quantity of modified segments for high-order and two-stage modified elliptical helical gears, and poor adjustment capacity for transmission ratio, the formation mechanism of a high-order multistage modified ellipse was studied, and a unified mathematical expression of the family of ellipses was derived Thus, a design procedure for the helical gear pairs of the high-order multistage modified ellipse was suggested, and then their transmission characteristics were discussed exhaustively Moreover, some checking methods such as curvature radius of pitch curve, convexity, pressure angle, undercutting, and contact ratio were offered Finally, two design cases, including two-order and three-stage modified elliptical helical gear pair and two-order and four-stage one, were implemented The cases indicate that a high-order multistage modified elliptical helical gear can be utilized in practice

Durability of injection moulded asymmetric involute polymer spur gears

Abstract: Asymmetric tooth profiles with different pressure angle at drive and coast sides are being considered to enhance the gear performance. In this work, experimental investigations were carried out to evaluate the fatigue and wear performance of injection moulded asymmetric polypropylene spur gears using the power absorption gear test rig. Test gears exhibited wear failure at lower loads and tooth bending failure at higher loads. Periodic measurement of gear tooth thickness and weight loss was carried out to quantify gear tooth wear. Sudden rise in measured gear temperature and failure morphology confirmed bending failure at higher loads. The results revealed that asymmetric gears exhibited inferior performance than that of symmetric gears. This behaviour is due to the reduced contact ratio, increased normal load and increased height at which worst load act on the gear tooth profile for the considered test conditions.

Multi-ball ball injector

Abstract: The invention discloses a multi-ball ball injector which is mainly composed of a body, a rotating gear, an upper cover, a ball loading cover plate, an upper connector, a driving shaft, a driving gear, a balancing weight, a control line, a remote console, a stepping motor and a lower connector. The body is provided with an annular cavity and a circular cavity which are used for containing the rotating gear and the driving gear respectively; the upper cover is arranged on the body and provided with a through hole of which the diameter is equal to that of a ball storing hole formed in the rotating gear; involute gears are adopted as the rotating gear and the driving gear, the modulus and the pressure angle of the gears are same, the rotating gear is provided with N cylindrical through holes (N is better to be smaller than or equal to 12 for controlling the size and weight of the ball injector) used for storing setting balls, N-1 setting balls can be stored, and the other cylindrical through hole is used for being communicated with a ball injecting channel; the setting balls are placed in the ball storing holes formed in the rotating gear in the clockwise direction according to the sequence from large to small. According to the multi-ball ball injector, the defects that in the prior art, the structure is complex, and the number of the setting balls which are injected for one time is difficult to control are overcome.

Pressure angle in parallel mechanisms: From planar to spatial

Abstract: This paper presents the evolution process of pressure angles from planar parallel mechanisms to spatial parallel mechanisms. Manipulability and condition number, which are frequently used in the optimum design of parallel mechanisms, are introduced from serial robots at first. Then, both theoretical analysis and practical experiences demonstrate that these concepts seem imperfect when they are used in parallel mechanisms. For this reason, this paper introduces the pressure angles in planar 4-bar mechanisms to spatial parallel mechanisms, which include redundant parallel mechanisms. Two kinds of pressure angles extracted from the determinant of direct and indirect Jacobian matrices are investigated. Moreover, two comprehensive and visible global performance indices are defined, showing the advantages in evaluating the workspace, singularity and motion/force transmission capabilities. With a 2-DOF planar and a 3-DOF spatial parallel mechanism as examples, the application of the performance indices is investigated and compared with the condition number at last. The proposed concept can be extended to other spatial parallel mechanisms.

Gear and bicycle gear change mechanism including gear

Abstract: A bicycle gear change mechanism includes a first gear including first teeth and a second gear including second teeth. Each of the first teeth includes a first surface and a second surface. The first surface defines a first pressure angle. The second surface defines a second pressure angle. The first pressure angle differs from the second pressure angle. Each of the second teeth includes a third surface and a fourth surface. The third surface defines a third pressure angle. The fourth surface defines a fourth pressure angle. The third pressure angle differs from the fourth pressure angle. The second gear engages the first gear.

Poor planetary gear mechanism of few tooth of cycloid tooth

Abstract: The utility model discloses a poor planetary gear mechanism of few tooth of cycloid tooth, it is in by cycloid internal gear and setting the cycloid internal gear in and the outer gear of cycloid that sets up with cycloid internal gear meshing, cycloid internal gear and the contacting line of cycloid external gear be the circular arc, the the?arc?RADIUS who establishes the contacting line is r, the pitch radius of the cycloid internal gear pitch radius that is r1 and cycloid external gear be r2, r1 then > r r2, the contacting line respectively when the pitch circle pure rolling of the pitch circle of cycloid internal gear, cycloid external gear, the contacting line on a bit to generate two gear tooth apical tooths respectively wide. The utility model discloses having in the transmission and manyly participating in the meshing simultaneously to the tooth, and the pressure angle is little to make the bearing capacity of mechanism improve, the gear tooth root divides does not basically participate in the meshing by a wide margin, and its flank profil can require nimble design according to the structure, does not have the undercut scheduling problem. The utility model discloses simple structure, the part is few, and manufacturing process easily realizes.

Method of correcting process tolerance of gear grinder

Abstract: PROBLEM TO BE SOLVED: To correct a helix angle without changing a pressure angle of a workpiece, by using a simple method without correcting a shape of a dresser.SOLUTION: A correction value of a phase between a vertical axis of a work table and a central axis of a grindstone is obtained from an error of a helix angle, and a gear shape is predicted in the case that a grindstone shape is changed according to a grindstone molding condition in which Y-direction feeding of a screw-like grindstone is corrected in accordance with the correction phase, and then an error of a pressure angle of a tooth surface in that case is estimated, and a pressure angle amount to be corrected, when a feed angle between a dresser rotational axis and a grindstone central axis is shifted before correction, is predicted in order to calculate a correction angle, and after correcting the screw-like grindstone by using a dresser in a posture that the feed angle is corrected only by the calculated correction angle, a workpiece is ground.SELECTED DRAWING: Figure 5

Influence of Module and Pressure Angle on Contact Stresses in Spur Gears

Abstract: Abstract—Contact stress between meshing gear teeth depends upon the material pair, normal load and the teeth geometry. Normal load at different points of contact changes during contact period, which depends upon the contact ratio. For identical material and operating conditions, contact ratio and the teeth geometry depends upon module and pressure angle of the gear pair. In the present work contact stress and contact fatigue analysis of spur gears has been carried out for identical operating conditions, for different values of module and pressure angle. Results of the investigation indicate decrease in contact fatigue life with increase in module as well as pressure angle.

Worm helical drive is vice based on become pressure angle

Abstract: The utility model discloses a worm helical drive is vice based on become pressure angle. In order to achieve the purposes, the utility model discloses worm helical drive is vice based on become pressure angle contains intermeshing's worm and helical gear, helical gear transverse module (Mt2) worm axial plane modulus (Ma1), helical gear terminal surface reference circle profile angle ( alpha n2) > worm axial plane reference circle profile angle ( alpha n1), oblique gear indexing circle helical angle ( beta 2) worm axial plane lead -angle ( lambda 1), helical gear terminal surface reference circle profile angle ( alpha n2) worm axial plane reference circle profile angle ( alpha n1) is less than 10. The vice transmission of worm helical drive is reliable, durable, and it is easy to make.

Gear pressure angle direction local vibration signal acquisition method based on microsensor

Abstract: The invention provides a gear pressure angle direction local vibration signal acquisition method based on a microsensor. The method comprises the steps of S1, installing a dual-axis accelerometer on an end face of a gear, acquiring X-axis and Y-axis vibration acceleration signal values of the gear through the dual-axis accelerometer, and filtering the obtained signals through a linear phase filter; S2, carrying out group delay correction for the filtered signals, and obtaining low frequency rotation speed signal data and high frequency rotation speed signal data; and S3, obtaining an instantaneous angular position signal of the dual-axis accelerometer through Hilbert transform, and further composing a vibration acceleration signal in a gear pressure angle direction. The obtained signal directly reflects the vibration and impact conditions of a gear excitation source, is free from the influence of a transmission path and more sensitive to early failure, and provides a new means for predicting and diagnosing the failure of the gear.

Optimization design method of offset cam type air inlet control mechanism

Abstract: The invention relates to an optimization design method of an offset cam type air inlet control mechanism. The optimization design method is characterized in that an offset cam type structure with a cam and a cam shaft in an integral structure is used; a jacking pin is driven to do linear movement along a guide groove through the cam curve surface; a cam eccentric pitch and the jacking pin contact curve surface are optimized, so that the cam curve surface drives the jacking pin to meet the thrust equivalent and unbalance loading balance principle; the large-force arm and large-moment function is realized; the installation in a narrow space is convenient. The method has the beneficial effects that the curve surface-curve surface contact obtains the same thrust as the curve surface-plane contact through optimizing the jacking pin contact curve surface; the thrust equivalent principle is met; in addition, the reasonable jacking pin cylinder radius dimension can be obtained through enabling the jacking pin contact curve surface to adapt to the jacking pin cylinder radius change; the cam eccentric pitch and the jacking pin contact curve radius is selected, so that the pressure angle change amplitude is minimum; the symmetrical distribution along the jacking pin axial line is realized, the offsetting balancing principle is met; the small-force-arm large-moment function and the structure compactness requirements are met; the installation in the narrow space is convenient.

Big-modulus long rack machining method

Abstract: The invention relates to the field of machining, in particular to a big-modulus long rack machining method. The method comprises the following steps: clamping, including that a blank of a rack is mounted in two machine vises along a longitudinal workbench and is rectified; cutter mounting and pressure angle guaranteeing, including that after a saw blade milling cutter is mounted on a vertical milling head before machining, the 20-degree pressure angle of the rack is guaranteed, the angle of inclination of the vertical milling head is 70 degrees, the vertical milling head clockwise rotates 70 degrees, and the vertical milling head counterclockwise rotates 70 degrees when the left side of a tooth profile is milled; milling cutter diameter and thickness selection, including that the diameter of a milling cutter is as small as possible on the premise that a cutter bar doesn't touch the workpiece, the thickness of the milling cutter considers that the milling cutter cannot damage the left side of the tooth profile when used for milling the right side of the tooth profile and cannot damage the right side when used for milling the left side, and the milling cutter with a proper diameter is selected and used according to the width of the bottom of a tooth groove; and moving the workbench a pitch by using an indexing plate. The method is simple in machining process and easy to operate, can ensure the machining quality and the dimensional precision of the workpiece, improves the production efficiency and reduces the production cost.

Design and Testing of Gears Operating between a Specified Center Distance Using Altered Tooth-sum Gearing (Z± Gearing)

Abstract: Altered tooth-sum gearing is a unique type of non-standard gearing having their profiles shifted due to altering the tooth-sum for a specified center distance and module. This approach is aptly termed as Z± gearing because it involves increasing the sum of teeth (positively altered toot-sum or aptly Z+ gearing) or decreasing the sum of teeth (negatively altered tooth-sum or aptly Z− gearing) of the mating gears working on an operating pressure angle. Here, both the center distance and gear ratio remains unaltered, such a study is less explored in gear research. This paper deals with determining experimental bending stress in standard and altered tooth-sum spur gears having involute form, further the results are compared with AGMA bending stress. For this purpose a Gear Tooth Bending Test (GTBT) fixture is developed which uses a single tooth specimen having a strain gauge bonded in its fillet region. Under the application of load a strain indicator reads out the strain. The specimen is a single tooth model having accurate involute profile and circular fillet, it is developed using advanced modeling software and manufactured using CNC machine. From the experiment it is observed that the tooth of Z− gearing subjected to positive profile shift has a lower bending stress (favorable) and the tooth of Z+ gearing subjected to negative profile shift has a higher bending stress (unfavorable, of course with higher contact ratio) compared to the tooth of standard gearing. This infers that the bending strength of a gear tooth can be influenced by altered tooth-sum design. The results obtained closely agree with AGMA values.

Design of Cam Mechanism with Negative Radius Roller-Follower

Abstract: Cam mechanisms with a negative radius roller-follower allow the design of simple machines capable of exerting remarkably high forces. Furthermore, the concave-convex nature of the contact surface between the cam and the follower results in a low contact stress and the ready formation of a lubricating layer. This paper presents a simple method for the design and analysis of a cam mechanism with a negative radius roller-follower. In the proposed approach, conjugate surface theory is employed to derive a kinematic model of the cam mechanism. Analytical expressions for the pressure angle and principal curvatures of the cam profile are then derived. The validity of the proposed design methodology is demonstrated by machining a cam mechanism having a negative radius rollerfollower with a radius of 100 mm.

Optimisation of the Geometric Design Parameters of a Five Speed Gearbox for an Automotive Transmission

Abstract: Optimisation of the geometric design parameters of a five speed gearbox for an automotive transmission is studied. The bending stress is considered as the objective function, and the design parameters are optimised under several constraints, including contact stress and constant distance between gear centres. During optimisation, the contact ratio changes with respect to pressure angle, and the effects of the contact ratio and profile modification on tooth bending stress are analysed. By optimising the geometric design parameters of a gearbox, including the module, number of teeth, helix angle and face width, it is possible to reduce tooth bending stress and obtain a light-weight-gearbox structures. It can be concluded that increasing the contact ratio results in a reduced tooth bending stress; however, in contrast, increasing the pressure angle caused a reduction in the contact ratio and an increase in tooth bending stress and contact stress. In addition, it can be concluded that positive profile modification reduces tooth bending stress. All of the geometric design parameters determined by optimisation satisfy all constraints.

Anti-interference gear and rolling cutter thereof used for machining

Abstract: The invention discloses an anti-interference gear and a rolling cutter thereof used for machining capable of reducing interference amount of gear engagement. The tooth shape comprises following parameters: h-whole depth of tooth, h-xy: tip relief; hs-tooth addendum; sc1- arc tooth thickness; sj-string length; an-a pressure angle; afd-a tip relief angle; az-an increasing angle; and Rpfn-circular angles. An included angle, az, is formed by a first tooth surface and a second tooth surface. An included angle, afd, is formed by the second tooth surface and a vertical surface is a tip relief angle. The relations among the pressure angle am, the tip relief angle afd and the increasing angle az is afd equal to arctan(tan(an)+Delta/tan (0.4m) ); az is equal to afd-an. In the formula, m is the module of gears, delta is anti-interference amount of gears. The value range is 0.02 to 0.09. The anti-interference gear and the rolling cutter thereof used for machining have following beneficial effects: a simple structure is obtained; anti-interference amount of gear engagement is greatly decreased to facilitate using and improve service lifetime of gears.

Design and Analysis of High Speed Helical Gear with Different Helical Angles

Abstract: Marine engines are among heavy-duty machineries, which need to be taken care of in the best way during prototype development stages. These engines are operated at very high speeds which induce large stresses and deflections in the gears as well as in other rotating components. For the safe functioning of the engine, these stresses and deflections have to be minimized. In this project, we created one helical gear with calculations in CAD tool Creo-2/Pro-E which is having helical angle 20 degrees and face width 32mm and pressure angle 20, by using CAE tool ANSYS WORKBENCH we applying high rotational speed and high pressure and high torque values in static structural then we finding deformation of the object and maximum stress values and safety factor values The aim of this project is reducing the stress values on the object, to minimizing the stress we following 3 methods 1. Design constant material change 2. Design changing material constant 3. Design and material both changing

Contact Fatigue Strength Design of a Slewing Bearing Based on i-PGS

Abstract: To overcome the large ring gear manufacturing problems seen in slewing bearings and girth gears, pin gear drive units have been developed. Among them, a novel slewing bearing with an internal pinwheel gear set (i-PGS) is introduced in this paper. First, we consider the exact cam pinion profile of i-PGS with the introduction of a profile shift coefficient. Furthermore, a new root relief profile modification for the i-PGS cam pinion is presented. Then, the contact stresses are investigated to determine the characteristics of the surface fatigue by varying the shape design parameters. The results show that the contact stresses of i-PGS can be reduced significantly by increasing the profile shift coefficient. In addition, the contact ratio, a measure of teeth overlapping action, decreases with the decrease of the allowable pressure angle.

Gear drive type gear model at zero pressure angle becomes appearance

Abstract: The utility model discloses a gear drive type gear model at zero pressure angle becomes appearance comprises zero degree pressure angle simulation rack slotting tool, the 5th gear, fourth gear, third gear, second gear, first gear, bottom plate, support paper disc and coupling ring, and first epaxial first gear can mesh the transmission with the 5th direct geared, perhaps directness and the 5th gear engagement of first epaxial first gear, but pass through a series of gear drive, first gear and the 2nd gear engagement, coaxial corotation can be realized to second gear and third gear, the third gear is through fourth gear and the 5th gear transmitting movement of each other, the primary shaft, secondary shaft can slide from top to bottom by the inslot on the bottom plate, guarantee each centre -to -centre spacing to the correct meshing of drive gear, for the drive ratio that changes first gear and the 5th gear, first gear, second gear tooth and third gear can quick replacement the gear of same tooth number not become, through adjusting two distances between the sword tooth, can depict the involute gear flank profil of different moduluses.

Deep Research on the High Speed Printing Machine Mechanism Output Member

Abstract: This article is an expand research about second size synthesis task of disc mechanism with floating roller push rod. By taking the cam-linkage combination mechanism of high speed printing machine as the research object, the travel angle of rocker m of its output member was analyzed and explored. According, in different allowable pressure angles [], relationship of zC, r0 and m were analyzed, optimal pressure angle []* and optimal cam basic radius r0opt * were solved. Regardless of digging the potential of existing mechanisms or extending scalable coverage, the above analyses have important reference value and guiding significance.