Relief Grinding Research Articles

Study on relief grinding interference checking method of toroidal worm wheel hob

The cutting tooth density of the toroidal worm wheel hob affects the quality of the hobbed worm wheel surface. The more the number of the cutting teeth, the higher the accuracy of the hobbed worm wheel surfaces. However, if the tooth density is greater, it’s easier to cause the grinding wheel to interference with other cutting teeth when grinding the relief surfaces, and the structure of the adjacent cutting teeth will be damaged. Therefore, this paper studies the checking method of grinding interference of relief surfaces, and then puts forward a design method of the maximum cutting tooth density to avoid grinding interference. Based on the point contact generation method, a relief grinding method of the toroidal worm wheel hob is proposed, and the grinding motion model is established. By analyzing the grinding processes of each relief surface, the variation law of grinding interference is obtained, and the relief grinding checking method is established based on the defined interference angles. The maximum interference position is determined, and the maximum number of the cutting tooth to avoid grinding interference is obtained. The study provides the key theoretical basis for the precision manufacturing of the high-density complex toroidal worm wheel hob.

Modelling and experiment of gear hob tooth profile error for relief grinding

Gear hob is an important tool that is most used in gear processing. Hob accuracy directly exerts an overwhelming influence on the quality of the processed gear. Generally, the hob tooth profile accuracy is mainly determined by relief grinding process. Studies on tooth profile errors of gear hobs caused by severe friction and cutting with the high-speed rotation of the wheel during the form grinding machining of hobs are limited. Thus, a theoretical model of the tooth profile error prediction under different machining parameters was established based on the analysis of coupling influence of high temperature and high strain rate on gear hobs in the relief grinding process. The model was completed on the basis of the dynamic explicit integral finite element method of thermo-mechanical coupling. Through the prediction model, the influence of the grinding depth ap, feed speed Vw and grinding speed Vs on the tooth profile error can be analysed. In addition, an algorithm for accurately calculate the grinding wheel axial profile by combining instantaneous envelope theory and hob normal tooth profile was proposed. The hob relief grinding experiments were carried out using the proposed grinding wheel profile algorithm. The relative error of the prediction obtained by comparing the calculation results of the prediction model with the experimental results is within 10%. Results prove the validity of the prediction model. This finding is greatly important for optimising the accuracy of hob relief grinding.

Modeling and experiment of grinding wheel axial profiles based on gear hobs

Hobbing is one of the crucial gear manufacturing processes with high precision and high efficiency. In order to improve the accuracy of hobbing and hob relief grinding, more precise grinding wheels are demanded for relief grinding in the production of gear hobs. In this paper, a new and accurate mathematical method for calculating the axial profile of grinding wheel based on the corresponding gear hob to be ground is proposed. Considering that most researches have been conducted to focus on the optimization of hob geometric feature and only can be applied to a specific type of hand of helix and rake angle of gear hobs. The method in this paper can be served as a general algorithm for generating axial profile of grinding wheels on the basis of the spatial envelope theory, the principle of coordinate system transformation, and studies on normal profile of single-tooth. The accuracy of grinding hobs is based on applying the approach in practical manufacturing. Taking two typical different kinds of pre-grinding gear hobs as examples for calculation and experiment, the results of tooth profile errors strengthen the position that the validity and feasibility of this method, it can be employed for gear hob design and grinding processing.

Relief grinding of planar double-enveloping worm gear hob using a four-axis CNC grinding machine

Compared with single-enveloping worm gearing, double-enveloping worm gearing can provide the same load capacity with a more compact volume and a higher efficiency. However, that the relief grinding of its hob can not be finished automatically till now limits its applications because all of the cutting edges on the hob have different shapes and spiral angles. In this paper, a pioneering method is proposed to relief grind the planar double-enveloping worm gear hob by adding two additional translational motions of the generating plane in addition to the rotation motions of the hob and the generating plane. A mathematic model is built for the relief grinding of the hob. A series of related data of the four motion parameters when grinding different points of the land edges of the different hob teeth are solved out, and the relief surfaces of different hob teeth can be ground continuously by using the data. The method is verified by using software VERICUT. Furthermore, a worm gear hob is relief ground on a four-axis CNC enveloping worm grinding machine by using this method.

4-Axis CNC Machine Tool for Relief Grinding Sphere Gear Hob

A new 4-axis machine tool, which is used for relief grind of sphere gears hob including spherical hob, elliptic hob and arc surface hob, is developed. The principle of relief machining of spherical hob is introduced first. Transmitting system, numerical system and some key techniques are then introduced. The machine tool can be reconfigured in machining of arc worms and spatial cams beside of machining of spherical hob. Four forms of the machine tool for machining different workpiece are also introduced. DOI: http://dx.doi.org/10.11591/telkomnika.v10i7.1557

Numerical Control Remanufacturing for Relief Grinding Machine

The remanufacturing for the traditional idle relief grinding machine is introduced in this paper to overcome its shortcomings, such as low precision, low automation degree and poor flexibility. The drive system of the traditional relief grinding machine was renovated with ball-screws and servo-drive system Sinamics S120, the original control system was replaced by numerical control system Sinumerik 828D. After remanufacturing, the mechanical structure of the traditional relief grinding machine is simplified and the machining accuracy meets the requirements. The automation degree and the flexibility of the machine are enhanced, and the labor intensity of the workers is reduced.

Relieving of Pinion Cutters with Hob

Relieving of pinion cutters with a hob to reduce a grinding stock in relief grinding is introduced. The profile of the hob was calculated through virtual conical hobbing (cutting of the hob by the pinion cutter with a required cutting edge). The hob was manufactured and used for conical hobbing of the pinion cutter. Obtained results are as follows. (1) Both tooth profiles of the pinion cutter conically hobbed with a standard hob are different. (2) Both pressure angles of the hob that can conically hob the pinion cutter with the exact cutting edges are different. In this case, the step is produced at the tooth top of the hob by the difference in level of the rake faces of the pinion cutter. (3) Both relief angles of the pinion cutter conically hobbed by the hob with the calculated profile are different a little. In this case, by changing the helix angle in conical hobbing, both relief angles are made equal. (4) The trial-made hob was designed and manufactured, and hobbing tests of the helical pinion cutter were conducted. As the results, the possibility was shown that a cut pinion-cutter that does not need relief grinding can be manufactured.

Relief Grinding of Pinion Cutters with Trapezoid Wheel

Relief grinding for involute helical pinion cutters with no profile error is realized by through grinding with a trapezoid-like grinding wheel. As a calculation example, an involute helical pinion cutter with semi-topping and protuberance cutting edges is used. First, a method for calculating the grinding wheel profile to finish the tooth flanks of the pinion cutter with the exact cutting edges is proposed. Next, the profile errors of cutting edges after regrinding are calculated and evaluated by means of the tooth profile of the work gear being shaped by the reground pinion cutter. As the results, it was found that the profile errors and the changes in shapes of the semi-topping and protuberance cutting edges after regrinding are very small. Finally, the usefulness of the proposed methods was confirmed through the grinding tests of the pinion cutter.

Calibration and Calculation of Interference in Hob Relief Grinding

Grinding wheel diameter is one of the most important parameter during the entire process of hob relief grinding and it must be analyzed and tested to avoid interference during the relief grinding. Graphical analytical and calculation method is proposed in this paper. Relief grinding interference issues are graphically analyzed and the formulas of relief grinding interference are derived. The interface is designed to calculate the maximum grinding wheel diameter of different parameters hob [1]. This method provides the basis for selecting grinding wheel rationally.

Design of 4-Axis Reconfigurable CNC Machine Tool for Relief Grinding Sphere Gear Hob

a new 4-axis machine tool, which is used to relief grind sphere gear hob including spherical hob, elliptic hob and arc surface hob, is developed. The principle of machining of spherical hob is introduced first. Transmitting system, numerical system and some key techniques are then introduced. The machine tool can be reconfigured when machining of arc worms and spatial cams beside of machining spherical hob. Four forms of the machine tool for machining different workpiece are also introduced.

Improved Relief Grinding Method of Gear Hob with Equal Relief Angle

The regrinding error is the main factor affecting the eligible length of hob tooth,how to decrease the regrinding error is a hot issue in the research area of hob grinding.At present,researches focus on changing the trajectory of relief moving,because of no unified relief grinding path planning method,the research result is restricted in the practical application.For solving the problem,the calculation model of the hob relief angle is established with the Archimedes relieving motion to analyze the interaction between the increasing relief angle of the hob and the accelerating tooth profile errors.Based on it,the improved relief grinding method of gear hob is proposed with equal relief angle(ERA).Furthermore,the relief grinding method with ERA is developed with the following two steps.Firstly,the convergence numerical solution algorithm of the tooth top curve is designed to form the wheel motion path which is compared with that of traditional grinding.The second step is to establish the solution model of ERA grinding wheel.In order to verify the effect of the method,hob grinding simulation system of 3D solid was built under the AutoCAD environment.The regrinding errors is analyzed by intercepting the hob axial profiles of the various regrinding angles with Boolean operations and further converting it to basic rack tooth,then the simulation example of zero rake straight flute hob is used to compare the regrinding errors between ERA grinding and traditional grinding.Finally,the experiments were implemented on the five-axis CNC relief grinder with the relief motion of ERA grinding driven by cam.The results of experiments show that the method can effectively reduce the regrinding errors of hob and grind expediently gear hob of AA rank and over.This research provide an effective model of relief moving path plan reducing regrinding error,and have practicable value in CNC relief grinder.

Method of Discreting Cusp Vectors of Helicoid and Its Application in Minimization of the Relief Grinding of Double Circular-arc Gear Hob

Self-intersect curve is often existent in the profile of forming cutter computed by the helicoid with cusp,which leads to form the big size of transition surface at the location of cusp of the helicoid processed by the cutter.Therefore,a method of discreting the cusp vector is proposed.It firstly defines a point and its normal vector as "point vector",and discrete the two point vectors formed by the two intersection curves at the location of cusp,which brings more information of the cusp into the computation process of profile for the accuracy improvement.Then,an algorithm for the minimization of transition surface is put forward.The discrete cusp vectors and the four point vectors on the cusp sides are used to compute the points which forming the profile of cutter.The cusp of the cutter and other four nearby points are obtained after the self-intersect is eliminated,which are used in the inverse calculation to gain the transition surface.The evaluation standard of transition surface is developed to optimize the installation angle of cutter within a certain range aiming at the minimization of transition surface.At last,the method is applied in the relief grinding for the double circular-arc gear hob.The actual processing result verifies that the method is helpful to reduce the size of transition surface effectively and also applicable to optimize the forming processing of helicoid with cusp.

211 台形砥石によるピニオンカッタの二番取り研削 : 砥石輪郭と研ぎ直し誤差(OS04 歯車の加工・製造)

211 台形砥石によるピニオンカッタの二番取り研削 : 砥石輪郭と研ぎ直し誤差(OS04 歯車の加工・製造)

Application of Air Cooling Technology and Minimum Quantity Lubrication to Relief Grinding of Cutting Tools

Application of Air Cooling Technology and Minimum Quantity Lubrication to Relief Grinding of Cutting Tools

非インボリュート歯車用ピニオンカッタの設計製作法の研究 : 第2報,二番取り砥石の輪郭設計法(OS9-1 軸受・設計)

非インボリュート歯車用ピニオンカッタの設計製作法の研究 : 第2報,二番取り砥石の輪郭設計法(OS9-1 軸受・設計)

2518 非インボリュート歯車用ピニオンカッタの設計製作法の研究

A precise analysis has been made for the designing and manufacturing method of a pinion cutter for non-involute internal gear, especially in the case the profile of the gear is given as a series of dispersive points. Firstly, theoretical equations are derived in order to obtain the profile of the pinion cutter. Secondly, it is clarified that under certain circumstances a singular point (a cusp) will occur on the profile of the pinion cutter, and that, because of the cusp, the interference phenomenon will occur on the profile of the pinion cutter. Thirdly, theoretical equations are derived to obtain the profile of a relief grinding wheel for the pinion cutter. Then, these theoretical equations are verified by practical designing and manufacturing of the pinion cutter.

Computer Simulation Technology in the Process of Shaping Milling Cutter Relief Grinding

Computer Simulation Technology in the Process of Shaping Milling Cutter Relief Grinding

GM-10 DEVELOPMENT OF RELIEF GRINDING SYSTEM FOR HOB FINISHING(GEAR MANUFACTURING)

A new relief-grinding system for a gear hob, consisting of a CNC relief-grinding machine and its support software, was developed. The CNC relief-grinding machine has a truing apparatus that can true a grinding wheel into an arbitrary profile. The relief-grinding machine has five control axes and can automatically finish the tooth flanks of the hob. The support software can calculate the grinding wheel profile to finish the tooth flanks of the hob with the given cutting edge profile and automatically produce NC programs used for truing of the grinding wheel, relief grinding of the hob, etc. Also, it can calculate the maximum regrinding stock and the regrinding errors of the hob being finished. The usefulness of the developed relief-grinding system is confirmed through the finishing tests of the involute gear hob.

A Study of Relief Grinding Method for Screw Rotor Hob with Pencil Type Wheel. 1st Report. Profile Design Method of Pencil Type Grinding Wheel.

A precise analysis has been made for a design method in order to obtain the profile of a pencil type relief grinding wheel for a hob which cuts a given screw rotor surface, especially in the case in which the cutting edge profile of the hob is given as a series of dispersive points. Firstly, it is clarified that under certain circumstances a singular point (a cusp) will occur on the profile of the relief grinding wheel corresponding to the cutting edge profile of the hob, and that, because of the cusp, the interference phenomenon will occur on the profile of the relief grinding wheel. Secondly, numerical analyses for the following two purposes arc proposed. One is to determine the interference by using a conditional equation of the cusps. And the other, which is more important is to obtain the profile of the relief grinding wheel. Then, these theoretical analyses are verified by applying them to the dimensions of screw rotor hobs.

103 スクリューロータホブのペンシル形砥石による二番研削法の研究(O.S.1-1 機械要素の高性能化)(オーガナイズドセッション1 : 新世紀に向けたトライボロジーと機械要素およびその応用技術)

103 スクリューロータホブのペンシル形砥石による二番研削法の研究(O.S.1-1 機械要素の高性能化)(オーガナイズドセッション1 : 新世紀に向けたトライボロジーと機械要素およびその応用技術)