Internal Helical Gear Research Articles

Computerized design, simulation of meshing and stress analysis of pure rolling internal helical gear drives with combined tooth profiles

The computerized design of non-generated pure rolling internal helical gear drives with combined transverse tooth profiles based on the active design of the meshing line function is presented. The application of different combinations of curves, namely circular arcs and involutes, to form the gear active tooth profiles is discussed. The parametric equations for tooth surfaces and the basic design parameters and equations of geometric sizing are proposed. The meshing performance and mechanical behavior are studied in terms of the contact patterns, maximum contact and bending stresses and peak-to-peak level of loaded transmission errors compared with a design of internal helical gear drive with corrected fillet. The combination of a circular arc and an involute connected at the pitch point to form the active tooth profile for both the pinion and the internal gear shows reduced maximum contact and bending stresses and lower peak-to-peak level of the loaded function of transmission errors. The proposed design of combined tooth profiles will contribute to lower the noise and vibration of the proposed gear drives, increase the endurance and life of the gear drive, and lower the heat generation due to pure rolling conditions of the achieved bearing contact.

Research on The Automatic Modelling Method for High Precision Finite Element Model of Internal Helical Gear

Research on The Automatic Modelling Method for High Precision Finite Element Model of Internal Helical Gear

Research on Grinding Method of Finishing Cutting Teeth for Internal Helical Ring Gear Broach Tools

Research on Grinding Method of Finishing Cutting Teeth for Internal Helical Ring Gear Broach Tools

Investigations on the pitting load capacity of internal spur and helical gears

Planetary gear boxes are suitable for numerous applications due to their compact design and high power density with coaxial in- and output. Especially in wind energy and industrial transmission systems but also in automotive applications such as automatic transmissions, planetary gear drives are commonly used. As a consequence of the continuous increase in the required power, the risk for flank damages has increased recently. Mostly, planetary transmissions are designed as helical gears due to improved NVH behavior and higher pitting resistance acc. to ISO 6336. However, systematic experimental investigations on the flank load carrying capacity of internal helical gears are not known so far.

Whole outline scanning measurement of internal gear by using CNC gear measuring machine

A three-dimensional probe is mounted on a specialized gear measuring machine whose measurement target is limited on the working flanks. The newly developed measuring machine has a coordinate measuring mechanism, aiming to be a highly versatile and relatively inexpensive measuring machine. According to our previous research, in addition to the working tooth surface, shape data of the root, bottom and tip profiles can be acquired with a single measurement operation. However, the target object for which this developed method has been applied was only the external cylindrical gear. In this paper, we applied and expanded the development method to the internal cylindrical gear and the evaluation of the axial displacement in the same cross-sectional scanning of the internal helical gear are performed.

Development of Two-axis Linkage PLC Control System for Electrochemical Machining Helical Gear

Without the effect of cutting force and cutting heat, electrochemical machining helical gear has the advantage of high production efficiency, good processing quality and tool cathode lossless. But the machine that based on small PLC control system does not have the function of helix interpolation, limiting the research and application of electrochemical machining helical gear. According to the principle of electrochemical machining of cylindrical helical gear, using pulse output instruction and powerful ability of floating point arithmetic of PLC, a helical gear two-axis linkage control algorithm is developed. This paper introduces the basic principle and presents a detailed derivation of algorithm formula. According to the principle and the algorithm formula, the control program is developed and the electrochemical machining of internal helical cylindrical gear is realized. Experiments show that the two-axis linkage control algorithm is stable, reliable and meet the needs of the helical gear electrochemical machining.

Design principle and modeling method of asymmetric involute internal helical gears

In the field of mechanical engineering, involute helical gears are widely used. Compared with the involute spur gear, helical gears have a high bearing strength, more smooth transmission, less impact and less noise. The internal gear pairs have the features of large transmission ratio, low vibration, low noise and low wear and hence are widely used in planetary gear transmission systems. In order to meet the requirements of high strength, high speed of the modern gear transmission systems, a new type of asymmetric involute internal helical gears is designed based on conventional involute gears. This paper discusses the gear shaper cutter modeling for machining this new gear, analyzes the formation principle of asymmetric tooth profile and establishes a three-dimensional modeling by SolidWorks. Through MATLAB simulation, pressure angle, tooth number, coefficient of displacement and contact ratio of conventional and asymmetric gear are compared and analyzed. Using ANSYS, two types of gears are compared on strength in order to demonstrate superiority of asymmetric tooth and further study about the asymmetric internal helical gears.

双リング式全方向車輪機構

In this paper, basic principle of active driving mechanism for omnidirectional wheel mechanism with a dual-rings is proposed. Active driving mechanism is composed of one outer helical gear and two dual-rings with internal helical gear. Proposed active driving mechanism is confirmed by developing basic prototype model.

Grinding path planning for the cutting teeth of helical broaching tool

Despite helical broaching being an excellent method for internal helical ring gear manufacturing with regard to its machining efficiency and precision, the manufacture of this special helical broaching tool is a severe challenge because of its complex geometric structure like dual-spiral and step-feed pattern of cutting teeth as well as the tiny offset of its cutting edges, particularly considering the expensive tool cost and long manufacturing period. Aiming at finding an efficient and reliable machining method for this type of helical broaching tool, this paper developed a complete set of machining routes and corresponding paths to grind its cutting teeth. Through detailed investigation, the geometric structure of the helical broaching tool, the tooth index model, and two kinds of tooth coordinate calculating methods were proposed. The rough cutting section is suggested to be machined in four stages, while the length-varying reciprocating path and the single-tooth grinding path patterns are presented. Then, a special step-feed structure-driven grinding path pattern and three stages are developed to perform the manufacture of the finishing cutting section. Finally, the progressively truthful machined entities validate that the developed machining routes and three path patterns are practicable for helical broaching tool manufacturing and that they are effective in enhancing the machining efficiency and quality. In addition, the concise operations prove the friendly programmability of the grinding paths.

Research on gear shaping strategy for internal helical non-circular gears and performance analyses for linkage models

Gear shaping is an efficient cutting method available for internal helical non-circular gears, but gear hobbing is not. Four methods and models of generating motion were built. Virtual shaping revealed that the method of equal arc-length of gear billet has the highest machining precision. Three methods of primary motion were built and analyzed respectively by using a kinetic simulation, which revealed that the method of keeping a constant velocity has the best dynamic performance. Two methods of additional motion were offered. Virtual shaping revealed that the two methods have the same precision, whether the gear has a right-hand helix or left-hand helix. Finally, two optimal shaping models were provided, and performed shaping experiments, respectively. The experiments showed that the shaping strategies and models are correct and feasible. Tooth-flank detections revealed that every tooth of the gears has the same precision using the optimal shaping models.

Study on Internal Helical Gear Worm Forging by Finite Element Analysis

This study applies the finite element method (FEM) to predict maximum forging load and effective strain in internal helical gear forging. Maximum forging load and effective strain are determined for different process parameters, such as modules, number of teeth, and die temperature of the internal helical gear forging, using the FEM. Finally, the prediction of the power requirement for the internal helical gear warm forging is determined. Therefore, the maximum forming force and strain distribution will be prediction for the different parameters of helical gear worm forging.

Effect of the cutter parameters and machining parameters on the interference in gear slicing

Current researches have not yet found the effect law of the cutter parameters and machining parameters on the interference in gear slicing, the interference between the cutter and machined gear often happens because the appropriate cutter parameters and machining parameters cannot be set, which reduces the gear machining accuracy. The relative position between the major flank face and edge-sweeping surface, distribution law of the interference area in forming process of edge-sweeping surface, and effect law of relative positions among edge-sweeping surfaces on the interference are studied by graphical analysis. The effect law of the cutter parameters and machining parameters on the interference is found. The effect law shows that the interference in gear slicing can be controlled when the relief angle measured on the top edge and feed of every rotation are chosen respectively larger than 9° and smaller than 0.15 mm/r. An internal helical gear is sliced with the spur slice cutter and the cutter parameters and machining parameters are set based on above the effect law. The machined gear is measured in Gear Measuring Center and the detection result shows that the comprehensive accuracy reaches GB/T Class 7, where some reach GB/T Class 6. The result can meet the gear machining accuracy requirement and shows that the effect law found is valid. The problem of the interference in gear slicing is solved and the gear machining accuracy can be improved.

二段充てん法による内はすば歯車の成形

In a previous paper, we proposed a two-step cold extrusion method of shaping external spur gears and helical gears. In the present paper, we describe how this filling method is applied to the shaping of internal helical gears. A specially designed mandrel for an internal helical gear utilizing the two-step filling method was used to expand and the inner diameter of the cylindrical workpiece. The specifications of these gears are as follows: module m=1.0, 1.25 and 1.5 mm; helix angle ß=20 deg; number of teeth Z=12-15 and whole depth h=2.00 module. The materials used were aluminum A1200 and low carbon steel S15C. The criterion for shaping complete teeth is discussed primarily in terms of punch pressure and the reduction in the area and the expansion ratio of the inner diameter of the workpiece. The approach that we described here successfully produced a filled up internal helical gear with only a few percent reduction in area. The punch pressure was very low, far below the strength of the punch material.

Research on Cutting-Tooth Outline Distortion of Internal Helical Gearing Machine Tool

Based on sports of machine tool and characteristic of involute outline internal helical gear , so gain mathematic model and tooth face equation of outline internal helical gear. Upbuild and analyzed milling load conditions of machine tool on the base of this, Upbuild milling load model of outline internal gear on the base of cutting-tooth distortion of machine tool, provide theory for involute outline internal helical gearing machine tool.

Modal Analysis and Parameters Research of Internal Helical Gears Based on AWE

The paper conducted a modal analysis of an internal helical gear based on AWE, and obtained its first 6 order natural frequency. Then the paper analyzed the influence of its parameters on the vibration characteristics of the internal helical gear, found that if the helix angle, the normal module, the number of teeth of the internal helical gear change, its vibration characteristics will change, but the change of the pressure angle doesn’t influence its vibration characteristics.

소형 헬리컬 기어 제조를 위한 분말 압출 금형 제작 및 실험

Extrusion process in the bulk material for fabrication of miniature helical gears has problems such as a high forming load and short tool life because the cross-section is complex and asymmetry. To overcome these problems, in this study, miniature helical gears were fabricated by Zn-22Al powder hot extrusion. The included die angle for minimum extrusion load and improving die filling was determined by FE-simulation. The Zn-22Al spheroidal powder produced by gasatomization were compacted and sintered for extrusion experiment. The dimension of helical-gear is 0.3mm in module, 3.35mm in pitch diameter, <TEX>$15^{\circ}$</TEX> in helix angle and the number of teeth is 12. All of the extrusion experiments were performed with internal helical gear die which was machined by precision electric discharge machining using the electrode. The experiment was conducted at <TEX>$190^{\circ}C$</TEX> to <TEX>$310^{\circ}C$</TEX> to obtain extrusive and mechanical properties. The extruded helical gears were analyzed through extrusion load, Vickers hardness and SEM images for each extrusion temperature. The powder hot extrusion process was successfully applied to fabricate a miniature helical gear.

Study on an internal gear with asymmetric involute teeth

Abstract In this paper, a double envelope concept is used to determine the basic profile of an internal gear with asymmetric involute teeth including driving and driven gears. The teeth of the proposed gear are asymmetric involute teeth. Based on this concept, a mathematical model of the meshing principles of a driven gear meshed with a driving gear is presented. Here, two gear types are illustrated. One is a spur gear and the other is a helical gear. The double envelope concept is used to determine the driven gear of an internal gear. Based on this concept, the required driving gear can be obtained by the envelope to a one-parameter family of a rack cutter surface. The obtained envelope becomes the generating surface. Then, the driven gear is the envelope for the family of the generating surfaces (driving gear). Through the proposed method, the profile of an internal gear with asymmetric involute teeth can be easily obtained. Using the developed mathematical models and the tooth contact analysis, the kinematic errors are investigated according to the obtained geometric modeling of the designed gear meshing when assembly errors are present. The influence of misalignment on the kinematic errors has been investigated. A comparison of the helical tooth and spur tooth shows that the internal gear with a helical tooth is superior to the internal gear with a spur tooth. Moreover, some results of change of shifting coefficient of internal gear in kinematic errors are studied. The goal of the current study is to investigate von-Mises stress in the proposed internal gear. A structural load is assumed to act on an internal spur gear and an internal helical gear. The rack cutter is shown for design and manufacturing of a driving gear. As an example, the internal gear with a gear ratio of 4:5 was presented. Using rapid prototyping and manufacturing technology, an internal gear with asymmetric involute tooth, a driving gear and a driven gear were manufactured. The rapid prototyping primitives provide an actual full-size physical model that can be analyzed and used for further development. Results from these mathematical models should have applications in the design of internal gear mechanism.

Fast Three-Dimensional Quasi-Static Analysis of Helical Gears Using the Finite Prism Method

This paper describes a model for analyzing external and internal helical gears. The finite prism method is used to study the elastic behavior of the structure. Contact deformations are also included in the model. Load sharing, pressure distribution, meshing stiffness and three-dimensional tooth fillet stresses are calculated at each instant. An experimental validation of the numerical model is also presented.

Tooth Deflection of External and Internal Helical Gears.

This paper presents study of the three dimensional bending and shearing deflection for external and internal helical gears. The deflection due to a concentrated load operated at the arbitrary position on the tooth flank is calculated by the three dimensional finite element analysis. Based upon this numerical solution, the approximate influence function that is applicable to arbitrary gear tooth dimension is derived. in order to apply this equation to non-standard designed gears such as addendum shifted gears, concept of equivalent tooth form is introduced. It is confirmed that the tooth deflections by the approximate function satisfactorily agree to that by FEM.

A model for the cutting force system in the gear broaching process

A mechanistic model for the cutting force system in a broaching process is developed. The broach geometry considered in the analysis is for a production operation used to produce an internal helical ring gear. The model for the force system is based on a description of the instantaneous chip load geometry and a relationship between the chip load and the three-dimensional cutting force system. The chip load geometry is based on the process kinematics and the involute-shaped cutting teeth of the broach. Shaping tests are performed to develop empirical equations for the cutting and thrust pressures. The model is validated through a comparison with actual forces generated during the production process.