Convex Tooth Research Articles

GENERATION AND TOOTH CONTACT ANALYSIS (TCA) OF HYPOID GEAR DRIVE

The present work covers the Face-Hobbing method for generation and simulation of meshing of Face hobbed hypoid gear drive. In this work the generation process of hobbed hypoid gear has been achieved by determination of the generation function of blade cutter. The teeth surfaces have been drawn depending on the simulation of the cutting process and the head cutter motion. Tooth contact analysis (TCA) of such gear drive is presented to evaluate analytically the transmission error function for concave and convex tooth side due to misalignment errors. TCA results show that the gear is very sensitive to misalignment errors and the increasing of the gear teeth number decrease the transmission error for both concave and convex tooth sides and ensure smooth motion with low vibration.

Surface modification and tooth contact analysis of variable hyperbolic circular-arc-tooth-trace cylindrical gears

Abstract. To improve the bearing capacity and provide the mathematical model basis for vibration and noise reduction of the variable hyperbolic circular-arc-tooth-trace (VH-CATT) cylindrical gear, the tooth surface modification design method based on the parabolic forming blade and cutter inclination was proposed. The geometric design of inclined cutter was completed. The modified tooth surface equation was deduced, and the influence of modification parameters on tooth surface curvature characteristics was analysed further. The tooth contact analysis (TCA) was established, and the influence of modification parameters on the elliptical contact area was analysed. Research shows that the parabolic coefficient a and the parabolic vertex position u0 have effects on the main curvature of concave–convex tooth surface, both the tooth profile and the tooth line direction, but the cutter inclination angle only has influence on the curvature of the tooth line direction, and the influence is larger. The cutter inclination angle γ, parabola coefficient a, and parabolic vertex position u0 have certain influences on the elliptical contact area. The cutter inclination angle γ is the most important modification parameter to improve the bearing capacity, but the excessive cutter inclination angle will cause bridge contact, the value range cutter inclination γ can be determined based on the tooth line radius. The research results provide a technical basis for improving the bearing capacity of the VH-CATT cylindrical gear and optimising the design.

Design and Experimental Study of Ultrasonic Vibration Feeding Device With Double Symmetrical Structure

In view of the limitations of traditional feeder driving mode in bulk material conveying, a new scheme of ultrasonic vibration feeding device with double symmetrical axis structure is proposed based on the existing traveling wave ultrasonic material conveying device. The outer sides of the upper and lower straight beam sections of the symmetrical conveying vibrator contain convex tooth structures, and piezoelectric ceramic sheets are pasted on the inner side; Based on the piezoelectric driving principle and the quarter wavelength principle, the conveying vibrator is dynamically designed, the influence of geometric size on the vibrator frequency is analyzed, the bending vibration mode of the vibrator is selected as 18 order, and the principle prototype of ultrasonic vibration feeding device is made. The resonant frequency difference measured in the experiment is close to that obtained by theoretical analysis, Moreover, the amplitude distribution of the conveying vibrator tooth surface is basically consistent with the finite element analysis results, and the influence law of material types on the conveying rate is compared and analyzed. The test results show that the ultrasonic vibration feeding device has a certain conveying capacity, the conveying rate is adjustable in a certain range, has high control accuracy, and meets the engineering application.

A compensation method for the eccentricity and inclination errors of spiral bevel gear based on improved ICP algorithm

Due to the manufacturing and assembly errors of the spiral bevel gear, the deviations between the measured tooth surface and its theoretical tooth surface will affect the measurement results of the tooth surface. After analyzing the tooth surface deviation of spiral bevel gear, this paper provided a compensation method to compensate the eccentricity and inclination errors by the registration of the theoretical and measured tooth surface. An improved iterative closest point (ICP) algorithm for the registration of the tooth surface was provided. The distance between the point in measured tooth surface and the nearest point in theoretical tooth surface is used to replace the minimum Euclidean distance, and the damping Gauss-Newton method is used to solve the geometric transformation matrix. Simulation experiments were carried out to verify the proposed compensation method. The compensation effect is over 93% for the concave tooth surface and over 89% for the convex tooth surface of the spiral bevel gear. The results also show that the improved ICP algorithm could compensate the eccentricity and inclination errors of the spiral bevel gear more precisely than the basic ICP algorithm.

Research on Spiral Bevel Gear Detection Based on Environmental Tooth Surface Error Correction Method

This paper studies the influence of the machine tool adjustment parameter error on the tooth surface error of the spiral bevel gear wheel processed by the double helix method. Based on the gear meshing principle, MATLAB software was used to establish the error tooth surface equation, and the analytical formula of the discrete point error of the tooth surface containing the machine tool adjustment parameter errors was derived. The topological map of the concave and convex tooth surface errors corresponding to the machine tool adjustment parameter errors was obtained and analyzed. The mapping relationship between machine tool adjustment parameter errors and tooth surface errors is determined, and the adjustment parameters that have a greater influence on the tooth surface errors are determined. With the help of the approximate expression of the topological diagram of the tooth surface error by the second-order surface, the influence weight of the machine tool adjustment parameter error on the tooth surface error is obtained. Based on the tooth surface error and the two-tooth surface error sensitive matrices, a tooth surface error correction model was established. The least square method of the generalized inverse matrix was used to transcend the equations to obtain the correction amount of the machine tool adjustment parameters. Finally, an example is used to verify the correction effect of the error tooth surface. The results show that the error of the tooth surface on the concave and convex sides after the correction is greatly reduced.

A new type of forceps for stabilizer removal after NUSS procedure

This paper describes the design and application of a new type of forceps for stabilizer removal after NUSS procedure. The forceps are made up of two strips of streamline forceps, which is composed of forceps handle and forceps head. One forceps head was designed as “Y” shaped, with an “L” shaped convex teeth set on each tip. It protrudes a small cylinder on the end platform of the other forceps head. Compared to the traditional operation method, with utilization of the forceps for stabilizer removal, it is expected that the operation time will be shortened and the bleeding will be reduced. The clinical application showed a good value of using the forceps in stabilizer removal after NUSS procedure. Level of evidenceLevel III.

Meshing theory and error sensitivity of mismatched conical surface enveloping conical worm pair

The point-contact meshing theory is well established for a mismatched conical surface enveloping conical worm pair. The contact equations with nine unknowns are established to ascertain the momentary contact points. In order to solve preceding equations expediently, the elimination artifice is adopted to transform it into its equivalent form with three unknowns. A datum point, where the drive ratio error of the worm pair equals zero, is also determined by solving a modified contact equation group. The angular position relationship between the two moving frames located at the contact point is made clear, and the relative principal curvatures are obtained correctly. The computing methods of the drive ratio error and the transmission error of the worm pair are elaborated systemically. The numerical results indicate that the mismatched worm pair has excellent meshing behavior and is insensitive to the assembly errors on the whole. Comparatively speaking, the worm pair is slightly more sensitive to the shaft angle error than to other types of errors. The error sensitivity of the worm wheel convex tooth surface is somewhat higher than its concave tooth surface.

Dynamic characteristics of torus involute gear drive

The torus involute gear drive originates from the involute spur gear drive, which is composed of a gear with convex teeth and the one with concave teeth. Previous researches of its mesh principle indicate that the torus involute gear can compensate large axial misalignments in parallel-shaft transmission, while its dynamic behavior has not been investigated comprehensively, or compared with that of the standard involute gear. This paper focuses on the dynamic performance of this type of gear. Considering the time variation of meshing stiffness, a 6-degree-of-freedom dynamics model of the torus involute gear pair is established, which counts in the effect of alternate meshing of single-double tooth pairs. Sliding friction in elastohydrodynamic lubrication is also included in the model. The numerical analysis for six cases is conducted, and the dynamic characteristics such as the dynamic transmission error, mechanical efficiency, sliding friction forces and minimum oil-film thickness are compared with those of the standard involute gear. The results show that, the torus involute gear drive exhibits good performances as the standard involute gear drive in transmission accuracy and mechanical efficiency, while, it has a better performance in lubrication condition. The study in this paper may lay theoretical foundations for practical application of the torus involute gears.

Neolasioptera pantaneira, a new species of Cecidomyiidae (Diptera) associated with Aeschynomene denticulata (Fabaceae) from Brazil.

A new species of gall midge that induces stem galls on Aeschynomene denticulata (Fabaceae) is described based on material collected in Pantanal (Mato Grosso do Sul, Brazil). This species is unique among the Brazilian congeners in having spatula with three convex teeth, cruciate, with defined anterolateral extensions, four lateral papillae on each side of the spatula, and three pairs of terminal papillae (larva), four-segmented palpi (adult), 17 flagellomeres (female), ovipositor about 11 times length of seventh tergite.

Matematyczny model ślimaka globoidalnego o wklęsłym i wypukłym zarysie zęba

This paper presents a mathematical model of globoid worm with concave and convex tooth profile. The method of creating the parametric equation of the profile was shown. The parametric equation of teeth surfaces of globoid worm with nostraight tooth profile was obtained.

Design formulae for a concave convex arc line gear mechanism

Abstract. Line gear is a newly developed gear mechanism with point contact meshing according to space curve meshing theory. This paper proposes a new form of line gear with a couple of concave convex arc tooth profiles. It has four characteristics. First, contact curve of the driving line gear is a cylindrical spiral curve. Second, two axes of a pair of line gears are located in the same plane with an arbitrary angle. Third, at the mesh point, normal tooth profiles of a line gear pair are a couple of inscribed circles. Namely, they form a couple of concave convex tooth profiles. Fourth, the tooth profile of a driving line gear is a convex, that of a driven line gear is a concave, and they are interchangeable. If only consider that the arcs of teeth at meshing point are tangent, the actual tooth surfaces may interfere outside of the meshing point. In this paper, the geometric condition of the tooth surface for a concave convex arc line gear mechanism is derived, and the optimal formulae of the tooth profile parameters are derived on basis of interference proof conditions. Finally, the 3-D modeling and kinematic simulation of line gear pairs show that the proposed line gear pairs can perform transmission normally. The proposed method will extend the application of line gear in the conventional power drive.

Geometry and contact characteristics of torus involute gears

Aimed at overcoming high sensitivity to machining or mounting error of line-contact conjugate surfaces, a novel torus involute gear drive is proposed which can compensate large axial misalignments and possess good meshing characteristics without lead correction. The torus involute gear is essentially a special spur gear with continuous shifting in the second order. Based on the processing principle of the torus involute gears, their mathematical models are established according to the corresponding imaginary rack cutter. In order to provide the approach to choose proper designing parameters, geometry characteristics of the torus involute gear are investigated: condition equations of tooth undercutting for a convex torus involute gear and tooth pointing for a concave torus involute gear are formulated utilizing the developed mathematical models, and the approach to checking tooth flank interference is provided. Contact characteristics of the gear set is studied through tooth contact analysis and finite element analysis. The simulated results produce useful information about tooth contact pattern, stress distribution, and transmission errors of the gear set.

Investigation on the Output Signal of Rotational Speed Sensor for Different Flux Surfaces between Gear Wheel and Sensor

Rotational Speed Sensors are typically used to measure rotational speed in automotive application such as ABS (Anti-lock Braking System), ASR (Anti Slip Regulation) or Gear Box. In terms of application area, rotational speed sensors transmit very important signal from gear wheel to ECU (Electronic Control Units). The output signal of rotational speed sensor (RSS) may not provide exact solution in high speed situation because RSS is a kind of inductive sensor which has discharge and charge time. Thus, response time of RSS may lead a problem for exact speed measurement while the output signal is settling. In this study to evaluate different flux surfaces, both low speed @0.8RPM and high speed @3992 RPM, 6 experiments were performed for normal, convex and concave teeth setups. It has been seen that the output signal form of convex teeth setup is more appropriate than normal teeth setup and concave teeth setup for sinus signal.

Matematyczny model obróbki kształtowej uzębień o kołowo-łukowym zarysie zębów typu Nowikowa

Article presents mathematical model of form machining of cylindrical convexo-concave Novikov gear teeth by means of disk-type tools. Example of these king of tools is disk-type milling cutter or grinding wheel. Moreover based on the given convex and concave tooth geometry the tool profile has been established.

WPŁYW PARAMETRÓW PRZEKŁADNI ZĘBATYCH O KOŁOWO-ŁUKOWYM ZARYSIE ZĘBÓW TYPU NOWIKOWA NA ŚLAD STYKU

Thesis presents the results of simulations, aiming at examining the influence of chosen Novikov gear parameters on its contact region. The parameters which influence have been established include the overlap ratio, ratio of radius of teeth profiles, ratio of convex tooth profile radius to pitch radius, normal pressure angle, translation of convex tooth profile along the contact line and axes distance error. Knowledge of the influence of gear parameters on its contact pattern enable to efficient establishing these parameters, which allows to compensate assembly errors or edge contact.

Theoretical Investigation of a Planar Rack Cutter with Variable Diametral Pitch

We propose an imaginary planar rack cutter with variable diametral pitch to manufacture the spherical gears of a wrist mechanism. The concept of the imaginary planar rack cutter is derived from the imaginary rack cutter. In general, the diametral pitch of the imaginary rack cutter is constant. In using the imaginary planar rack cutter with constant diametral pitch to cut a spherical blank material, the teeth generated will interfere with each other. Therefore, two matched imaginary planar rack cutters with a variable diametral pitch are proposed. One of the imaginary planar rack cutters consists of convex teeth and is utilized to generate a spherical blank material with concave teeth. The other consists of a concave one and is used to generate a spherical blank material with convex teeth. Through the two-parameter envelope theory and a software package, mathematical models of the spherical gear pairing were determined. Using a developed mathematical model, an investigation on the undercutting analysis of the proposed imaginary planar rack cutter is performed by tooth contact analysis. Finally, a numerical example is used to demonstrate the geometric model of a spherical gear generated by the imaginary planar rack cutter.

Modelling and bending strength analysis of cylindrical gears with arcuate tooth trace

Based on the analysis of precision moulding mechanism for cylindrical gears with arcuate tooth trace (arc gear), the equation for tooth flank of arc gear was derived preliminarily and the ideal concave and convex tooth flanks were got by MATLAB simulation to achieve graphics rendering. On this basis, with UG NX8.0, the accurate three-dimensional modelling of arc gear was established to be used for the finite element analysis. Then, for the problem that there is no standardised bending strength calculation formula of arc gear, with the aid of finite element method (FEM) this paper studied the relationship between tooth line radius and bending strength. With FEM analysis performed, it was confirmed that under the same conditions, the bending strength of arc gear could be significantly improved compared with that of spur gear and helical gear, and that variation curve of tooth root stress was obtained under the different tooth line radius. Therefore, the analysis method provides engineering applications value under the high-speed and heavy-load working conditions and theoretical basis for the strength theory and design of arc gear.

Contact сharacter of work surface of cylindrical gears tooth with conchoidal engagement line depending

Load capacity of gears depends on the character of work surfaces contact: two convex contact or contact the convex and concave surfaces. Therefore, the actual solution to the problem is to determine the geometrical parameters of the tooth, providing the most rational given character of their work surfaces contact. This fully applies to the gears with conchoidal engagement line for which this problem has not been studied yet.Тhere have been gotten the conditions defining the character of tooth work surface contact with conchoidal engagement line depending on the geometrical parameters of the original contour. There have been defined the original contours parameters providing convex-concave tooth contact and the contact of two convex teeth in the engaging meshing pairs. There have been given recommendations as for defining the parameters of the original contour depending on the character of contact in cylindrical spur gear work surfaces.

A Study of an Electro-magnetic Proportional Valve Actuator with Multi Convex Teeth for Generating High Thrust Force -Examination of Stator Shape-

A Study of an Electro-magnetic Proportional Valve Actuator with Multi Convex Teeth for Generating High Thrust Force -Examination of Stator Shape-

A Study of a Magnetic Pole Shape of an Electro-magnetic Proportional Valve Actuator with Multi Convex Teeth for Generating High Thrust Force

A Study of a Magnetic Pole Shape of an Electro-magnetic Proportional Valve Actuator with Multi Convex Teeth for Generating High Thrust Force