Showing papers on "Pressure angle published in 2007"

Vehicle stabilizer system

Abstract: PROBLEM TO BE SOLVED: To provide a vehicle stabilizer system having high practicality. SOLUTION: This vehicle stabilizer system 10 is equipped with a stabilizer bar and an actuator 32 which generates a stabilizer force which is a force for putting a wheel close to a vehicle body or separating them by rotating a stabilizer bar 28, and can perform vehicle height adjusting control by changing the stabilizer force. In the stabilizer system 10, the reverse efficiency of the actuator is made different depending on a direction in which the stabilizer force acts. In concrete, a pressure angle β between tooth surfaces of gears by which respective teeth of the two gears 58 and 60 of a reduction gear 42 which the actuator has are engaged and come into contact with is made different depending on a direction in which the stabilizer force acts. By this structure, the reverse efficiency of the actuator can be made low in one of the bound direction and the rebound direction. Since electric power required for maintaining the vehicle height in that direction is reduced, power saving is attained. COPYRIGHT: (C)2007,JPO&INPIT

Wave gear drive with continuous meshing, high ratcheting torque tooth profile

Abstract: A wave gear drive comprises a circular rigid internal gear and a flexible external gear inside the rigid internal gear. A wave generator in the flexible external gear flexes the flexible external gear into an elliptical shape. The cross-section of the flexible external gear perpendicular to the axis at a point in the tooth trace direction of the flexible external gear is set as the main cross-section. The rigid internal gear and flexible external gear are gears with a module m, and the flexible external gear has a number of teeth that is smaller than the number of teeth of the rigid internal gear. The moving route M of a tooth of the flexible external gear with respect to a tooth of the rigid internal gear that accompanies rotation of the wave generator when meshing of the teeth in the main cross-section is approximated by rack meshing. On the entering side of the meshing of the teeth to the major axis of the moving route M, a first similar curve AC is obtained by similarity transformation of a pressure angle .alpha. orthogonal to the direction of the moving route M. The first similar curve AC is employed as the basic addendum tooth profile of the rigid internal gear. A second similar curve CB is obtained by rotating the first similar curve AC 180° about endpoint C, and by a similarity transformation in which the first similar curve AC is multiplied by a ratio of similitude (1−λ)/λ. The second similar curve CB is employed as the basic addendum tooth profile of the flexible external gear.

Minimization of transmission errors in highly loaded plastic gear trains

Abstract: Transmission errors (TEs) are an important source of unwanted noise and vibration in gear drives. Errors can result from geometrical inaccuracies and from elastic deformations. Plastic drives are often loaded in a way that produces high deflections relative to steel gears, and the elastic component of TE is relatively more important. Furthermore, plastic gears are often run in mesh with gears made from steel or other metals. In this case there is a large difference in tooth stiffness, which leads to unusual TE problems. The current paper discusses the origins of elastic TEs and means of their calculation. A simple beam model is used to demonstrate the stiffness of a pair of meshing gear teeth. A finite-element analysis is used to refine this model and to run iterative tooth meshing enabling TEs to be accurately characterized. A number of TE traces from gear pairs running under high loads are included and compared with the theoretical predictions. Several different scenarios are proposed including ...

Method for determining a tilt angle of a vehicle

Abstract: A method for determining a tilt angle of a vehicle includes measuring accelerations of a vehicle in directions along a longitudinal axis, a transverse axis, and a vertical axis of the vehicle. A current tilt angle of the vehicle is calculated as a function of the measured accelerations. A magnitude-compensated tilt angle is calculated as a function of the current tilt angle, of a preceding tilt angle, and of the magnitude of the vector sum of the measured accelerations. A gyroscopically stabilized magnitude-compensated tilt angle is calculated as a function of the current tilt angle, of a preceding tilt angle, of the magnitude of the vector sum of the measured accelerations, and of a change in the tilt angle over a given time period calculated from angular rate data provided by a gyroscope.

Mathematical Model and Characteristic Analysis of Elliptical Gears Manufactured by Circular-Arc Shaper Cutters

Abstract: A circular-arc elliptical gear drive with convex (or concave) tooth profiles, which is used in an oil pump with a larger pumping volume, was simulated by using circular-arc shaper cutters with concave (or convex) tool profiles. Mathematical models of circular-arc elliptical gears, based on the theory of gearing and the gear generation mechanism, were also developed. The generated elliptical gear drive has a convex-concave tooth profile contact. Because of its complex geometry, the profile of circular-arc elliptical gears may exhibit tooth undercutting, and pointed teeth. Pointed teeth usually appear on the major axis of the elliptical pitch curve. A geometric relation was developed and applied to prevent the pointed teeth on the elliptical gears. A larger pressure angle at major axis and circular-arc radius can eliminate tooth undercutting and increase its tooth thickness at the addendum circle for small teeth. Moreover, a computer simulation program was developed to generate the tooth profile of circular-arc elliptical gears without tooth undercutting and pointed teeth.

Lapping and Superfinishing Effects on Hypoid Gears Surface Finish and Transmission Errors

Abstract: There are several geometric and working parameters, besides offset, that have minor effects on hypoid gears efficiency (i.e. spiral angle, pressure angle, lubricant type & temperature, surface finish, etc.). Some theoretical analyses of mechanical efficiency of hypoid gears show that surface finish has considerable effect on hypoid gear efficiency. This is due to a high sliding to rolling ratio in these types of gears. In this paper, a study on measuring of surface finish of both ring gear and pinion will be presented. Moreover, the effects of lapping and superfinishing on surface finish will be discussed. Using an accurate form-measuring machine, surface finish measurements were done on several experimentally produced hypoid gear pairs. Despite the fact that lapping is expected to improve the surface finish, measurement results show that ring gear’s surface finish becomes worse (roughness increased) after lapping while no consistent results for pinion surface finish were observed. However, it will be shown that lapping decreases transmission errors for both sides (drive and coast). Utilizing a Gleason single flank tester (SFT) 600HTT it will be shown experimentally that transmission errors up to the second harmonics for both sides will be decreased. In addition, it can be seen that lapping decreases surface finish variation among gear sets. As an expansion of the previous study [1] by the authors on lapping effects on surface finish and transmission errors, this paper will also present the effects of the superfinishing process on hypoid gears surface finish and transmission errors. This study shows the result of measurements taken before and after superfinishing, although superfinishing improves surface finish drastically it will be shown that surface finish quality will be decreased when gear sets are rolled together.Copyright © 2007 by ASME

Minimizing and Restricting Vibrations in High-Speed Cam-Follower Systems Over a Range of Speeds

Abstract: Over a range of cam speeds, the problems of minimizing and restricting vibrations in high-speed cam-follower systems over a range of speeds are formulated as constrained optimization problems. A universal Hermite cam displacement is suggested. The combination of these methods can form a general design environment. In this environment, the designer can arbitrarily select one to formulate as the objective function from quantifiable cam properties such as the residual vibration, primary vibration, pressure angle, radius of curvature, and contact stress, while the rest of quantifiable cam properties can be formulated as the design constraints.

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.

Development of Speed Reducer with Planocentric Involute Gearing Mechanism

Abstract: A new speed reducer with the planocentric involute gearing mechanism, which can be replaced with a cycloid drive, is developed. This speed reducer eliminates some significant disadvantages of the cycloid drive, which are difficulty in not only designing and manufacturing the tooth profile but also meshing the gears to maintain an accurate center distance. In this paper, to avoid tooth tip interference between internal and external gears and maximize a speed reduction ratio, a pressure angle, a tooth height, a profile shifting factor and the number of teeth are simulated. We manufacture a prototype based on these simulated results of the design specifications (the rated power of 350watts, rated speed of 3600rpm and speed reduction ratio of 41:1), of which the overall size is Ф146mm×95.2mm. A power efficiency test of the prototype is carried out to compare with the cycloid drive.

Pressure around a 20-degree Circular Cone at 35-degree Angle of Attack and Low Speed

Abstract: This paper reports results from comprehensive pressure measurements of a circular cone-cylinder model in a low-turbulence 3:0 1:6 m low-speed wind tunnel. The semi-apex angle of the cone is 10 . The results consist of detailed pressure distributions over nine stations on the cone at 35 angle of attack and Reynolds number of 0:9 10 6 based on the diameter of the cone base. The tests encompassed a complete coverage of roll angles in 9 intervals. The test conditions are chosen to be the same as those of a known test in the literature for validation purpose. Local and overall forces and moments are calculated from the measured pressures. The variation of local side-force coecien t normalized by the local diameter of the cone, with roll angle is nearly a square-wave curve. The primary state of the boundary layer is inferred from the measured pressures to study the origin of asymmetries. The association of local side force with a characteristic pressure at a given pressure station is shown independent of roll angle for various local side force and various pressure measuring stations. The conicity of the o w is examined. The complete measured pressures are documented in the Appendix for public use.

PROPER CONDITIONS OF MESHING FOR Hy-Vo SILENT CHAIN AND SPROCKET

Abstract: Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmis- sion of the silent chain with more efficiency and less noise.Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob,the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration,and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied.Experiments show that this new design method is feasible.In addition,the design of the pitch,the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle are studied.It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.

Computer Aided Design of Asymmetric Gear

Abstract: Gear design becomes inevitable for the development of any mechanical system and it necessitates considerable expertise. Due to the evolution of new materials and manufacturing processes, the utilization of asymmetric gears increases in recent years. Designers will be able to develop gear drives to handle larger torque with lesser noise and vibrations with the asymmetric profile. However the existing design procedure of symmetric gears does not holds good for these asymmetric gears. Hence by modifying tooth form factor, stress concentration factor, and load sharing factor, a MATLAB  code has been developed for designing asymmetric spur gears. Pressure angle limits were initially arrived by considering the gear tooth peaking and law of gearing. With in the range of pressure angle values, the asymmetric gear teeth which experiences minimum bending and contact stresses for the given loading condition can be chosen. In addition with the known number of tooth, module, and pressure angles of driving and coast side, asymmetric gear tooth coordinates were obtained which can be directly used for actual gear manufacturing

New Approach to the Local Synthesis of Spiral Bevel Gears

Abstract: The generating of two spiral bevel gears by the plane-top generating wheel with essentially different parameters of the head-cutter installation and motion is considered. For this case the necessary and sufficient conditions providing coincidence of normal vectors and surface curvatures in the designed point are presented as the vector equations system. The relations among blade pressure angle, head-cutter radius, radial distance, tool installation angle, machine centre to back, blank offset and velocity ratio are obtained. The developed methods make the opportunity to design equivalent machine-tool settings, to extend manufacturing possibilities of gear-cutting machines and to raise the load rating of the gear drive.Copyright © 2007 by ASME

Processing method of asymmetric gear with two pressure angles

Abstract: A double pressure angle asymmetric gear processing method belongs to gear technology field. The processing steps are: installing CAXA wire cutting software, inputting the involute equation and adjustment curve equation of asymmetrical gear work flank and non-work flank into the formula curve of drawing instrument column, inputting parameter into initial value column and stop value column, then inputting the equation of addendum arc into formula curve, setting the initial point of addendum arc parameter as the stop point of non-work flank adjustment curve; working out the tooth profile curve of involute gear, completing the tooth profile of whole involute gear through 360degreearray; transforming the total data of involute all-gear graph into wire cutting processing program order 3B code through the automatic transforming function of wire cutting software; the control system of wire cutting machine processes the involute gear which involute coefficient between 1.0 and 1.3289 through 3B code. The wire cutting process is more flexible, wheel carrying-capacity is higher and vibration is small.

Design and machining of cylindrical cam with meshing indexing disc

Abstract: Cams are fundamentally important machine elements, which provide a simple means of generating virtually any follower motion. This paper presents a simple yet comprehensive method for the design and machining of a cylindrical cam with a meshing indexing disc. In the proposed methodology, homogenous coordinate transformation and conjugate surface theory are employed to develop a kinematic model for the cam profile design. The pressure angle and the principal curvature of the designed cam are analysed using the analytical expression derived for the profile. The required NC data equations are obtained by solving the CNC link variables by equating the machine tool ability function with the tool location matrix. The proposed methodology is verified by machining the designed cylindrical cam using a 4-axis CNC machine. The inspection results obtained from a 4-axis CMM show that the profile measurements of the machining cam are in excellent agreement with those of the designed profile. The results confirm ...

The Optimization of a Novel Prismatic Drive

Abstract: The design of a mechanical transmission taking into account the transmitted forces is reported in this paper. This transmission is based on Slide-o-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-o-Cam, a transmission intended to produce a sliding motion from a turning drive, or vice versa, was reported elsewhere. This transmission provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. The pressure angle is a relevant performance index for this transmission because it determines the amount of force transmitted to the load vs. that transmitted to the machine frame. To assess the transmission capability of the mechanism, the Hertz formula is introduced to calculate the stresses on the rollers and on the cams. The final transmission is intended to replace the current ball-screws in the Orthoglide, a three-DOF parallel robot for the production of translational motions, currently under development for machining applications at Ecole Centrale de Nantes.

Cosine gear transmission mechanism

Abstract: The present invention belongs to the field of mechanical transmission technology, and is especially one kind of cosine gear and one kind of conjugate cosine gear transmission mechanism. The present invention solves the technological problem for providing one kind of cosine gear transmission mechanism with improved gear transmission performance and raised gear bearing capacity. Technologically, the present invention features that the cosine gear has cosine tooth profile curve, its conjugate gear has cosine tooth profile curve with amplitude and period determined y the required transmission ratio, two gears have near linear contact path, and the tooth profile curve of the cosine gear has the zero line of cosine curve as the pitch line, the period of cosine curve as the tooth pitch and amplitude of cosine curve as the addendum. The cosine gear transmission mechanism has great pressure angle, small slide coefficient, high contacting and bending strength and other advantages.

Spline connection device of telescopic universal-joint-pin type universal coupling

Abstract: The utility model relates to a spline connection device of telescopic universal-joint-pin type universal coupling, which is used to the power transmitting of rolling mill and the universal-joint-pin type universal coupling in the rolling machinery. A spline 1 connects with a spline 2, moreover, the tooth profile of the spline 1 and 2 are triangles, and the pressure angle Alpha is 30 degrees plus or minus 1 degree. The utility model has the advantages as the following: the device is novel structure; the triangle spline is advanced in that the structure is simple to be easy machining, furthermore, the device can be high precision machining, the machining accuracy can be control, and the precision of the automatic centring is high, etc. So the device is particularly suitable for the rolling machinery under the heavy load and heavy impact.

Pure rolling speed reducer

Abstract: A pure rolling reducer includes the eccentric reducing mechanism, the few tooth difference reducing mechanism and the few tooth difference output mechanism. The inner gear, the duplicate gear and the output gear all have the pressure angle with standard tooth shape and the groove width is 2-6 times than the tooth thickness. The inner gear and the duplicate gear are connected by the gear roller, also the output gear and the duplicate gear which the meshed process are all rolling friction. The two ends of the gear roller are connected by the flexible distance sleeve. The gear roller distance in meshed process is compensated by the flexible distance sleeve. The inner and the out gears mesh by rolling, so they have small friction loss, also every pressure angle of the gear is the standard pressure angle to get over the defects of the big pressure angle of the active tooth reducer, small circle force and low efficiency.

The Multiobjective Optimization of a Prismatic Drive

Abstract: The multiobjective optimization of Slide-o-Cam is reported in this paper. Slide-o-Cam is a cam mechanism with multiple rollers mounted on a common translating follower. This trans- mission provides pure-rolling motion, thereby reducing the fric- tion of rack-and-pinions and linear drives. A Pareto frontier is obtainedby means of multiobjective optimization. This optimiza- tion is based on three objective functions: (i) the pressure angle, which is a suitable performance index for the transmission be- cause it determines the amount of force transmitted to the load vs. that transmitted to the machine frame; (ii) the Hertz pressure used to evaluate the stresses produced on the contact surface be- tween cam and roller; and (iii) the size of the mechanism, char- acterized by the number of cams and their width.

Accuracy of Straight Bevel Gear by End Mill Using CNC Milling Machine

Abstract: Straight bevel gears are usually manufactured with various machines and systems, and the tooth profiles are produced by grinding or machining by means of a tool with many cutting edges. In recent years, the straight bevel gear has been manufactured by an end mill using a CNC milling machine because the use of the auxiliary apparatus, special cutters, and special machine tools are not needed. Using this method, the gear manufacturing with high accuracy is important problem. In this paper, the coordinate measurement of the straight bevel gear manufactured in this method is performed and the gear accuracy is evaluated. The tooth profiles of a straight bevel gear generated by a quasicomplementary crown gear instead of a conventional complementary crown gear is introduced. For this study, first the tooth profiles of the straight bevel gear were modeled using a 3D-CAD system and the gear was manufactured by an end mill using a CNC milling machine based on a CAM process. Afterward, the coordinates of many points on the gear tooth surfaces were measured at random using a coordinate measuring machine. This coordinate measurement provides the information about the factors relation to the gear accuracy such as pressure angle, tooth angle error, root cone angle, and apex to back and so on. Therefore, the values of the above factors were estimated and were compared with the theoretical ones, respectively.Copyright © 2007 by ASME

Method of setting optimum number of teeth of helical gear, and helical gear

Abstract: PROBLEM TO BE SOLVED: To provide a method of setting the optimum number of teeth of a helical gear which can reduce unpleasant gear noise more effectively by taking into consideration the hearing characteristics of a human. SOLUTION: A gear ratio, a distance between centers, a pressure angle, and a torsion angle between a pair of helical gears are determined, and the relationship between the number Z of teeth of each of the pair of helical gears and the engagement rate eof the pair of helical gears are calculated based on the values. Then the sound pressure level L G of the gear sound at the engagement frequency of the pair of helical gears is calculated from the relationship, and the sound pressure level of the gear sound is compared to a sound pressure level at the audibility limit with respect to the engagement frequency of the pair of helical gears of the vehicle, on which the pair of helical gears are mounted, at a predetermined vehicle speed. Then a frequency range is selected where the sound pressure level of the gear sound is relatively lower than that of the audibility limit, and the number of teeth which corresponds with the selected frequency range is set as the optimum number of teeth. COPYRIGHT: (C)2007,JPO&INPIT

Transmission torque limiter for vehicle

Abstract: PROBLEM TO BE SOLVED: To provide a transmission torque limiter for a vehicle in which an excessive torque produced during the abrupt starting of the vehicle is avoided, without increasing the size or the weight of each of the power transmission devices of the vehicle. SOLUTION: This transmission torque limiter has a side gear 40 functioning as a first rotating member and an engaging gear functioning as a second rotating member, in which a side gear piece 42 is meshed with a side gear shaft 44. Since pressure angle α is provided to the engaging gear, a thrust force that acts to disengage the meshed gears by the pressure angle α, when a transmission torque exceeding a predetermined level is applied thereto, is generated by providing the pressure angle α to the engaging gear. When the thrust force becomes larger than the biasing force of a disc spring 48, the meshed gears will be disengaged, since the transmission torque is cut off, and input of the excessive torque to each of the power transmission devices is averted. COPYRIGHT: (C)2007,JPO&INPIT

The Kinetostatic Optimization of a Novel Prismatic Drive

Abstract: The design of a mechanical transmission taking into account the transmitted forces is reported in this paper. This transmission is based on Slide-o-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-o-Cam, a transmission intended to produce a sliding motion from a turning drive, or vice versa, was reported elsewhere. This transmission provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. The pressure angle is a suitable performance index for this transmission because it determines the amount of force transmitted to the load vs. that transmitted to the machine frame. To assess the transmission capability of the mechanism, the Hertz formula is introduced to calculate the stresses on the rollers and on the cams. The final transmission is intended to replace the current ball-screws in the Orthoglide, a three-DOF parallel robot for the production of translational motions, currently under development for machining applications at Ecole Centrale de Nantes.

Bearing device for drive wheel, and its manufacturing method

Abstract: Provided is a driving wheel bearing device, which is improved in workability at a disassembling/assembling time thereby to reduce the cost and which eliminates a circumferential backlash of engaging portions thereby to attain a reliability and a steering stability. In the driving wheel bearing device, a hub ring (1) having a wheel mounting flange (4) integrally at its one end portion, a plurality of rows of rolling bearings (2) and a uniform universal joint (3) are removably united by screw means, and the uniform universal joint (3) is jointed to the hub ring (1) through torque transmission means. The torque transmission means is constituted to include a fitting profile (21) having a plurality of teeth (21a) uniformly arranged on the outer circumference of a shank (20), and a fitting profile (22) corresponding to the fitting profile (21) and having a plurality grooves (22a) uniformly arranged in the inner circumference of the hub ring (1) for engaging with the teeth (21a). The tooth faces of the teeth (21a) and the grooves (22a) have a predetermined negative pressure angle and a predetermined angle of inclination in the axial direction with respect to the axis, so that the circumferential backlash of the engaging portions can be eliminated to establish a firmly fitting state.

Study on profile of Roots vacuum pump rotor

Abstract: By adopting the method of reducing the pressure angle, this paper carried out an improvement on the profile of traditional involute rotorIn accordance with the meshing principle,the parameterized design of rotor profile was carried out,and a comparison was made on the area utilization coefficient with the traditional involute rotorThe study made clear that there were drops to some extent on the area utilization coefficient of the improved profile of involute rotor when compared with the traditional profile of the same structure,yet its coincident degree was decreased along with the increase of pressure angleIt raised the stability of rotor transmission and in the mean time raised the bearing capacity of rotor transmissionIt prolongs the service life,and possesses certain value of application