A Designing and Generating Method for Grinding Relief Surfaces of a Dual-Cone Double-Enveloping Hourglass Worm Gear Hob

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Chengjie Rui ◽  
Haitao Li ◽  
Jie Yang ◽  
Wenjun Wei ◽  
Xuezhu Dong

Land widths and relief angles of a dual-cone double-enveloping hourglass worm gear hob are important factors that influence the life and the hobbing performance of the hob. Both of them are obtained by generating relief surfaces of the hob. Due to the reason that all teeth of this type of hob have different profiles with each other, all of the relief surfaces are difficult to generate for keeping all cutting teeth with uniformed relief angles and uniformed land widths. For the purpose that land widths and relief angles could be machined precisely, this paper puts forward a designing and generating method for grinding the relief surfaces. The relief surfaces are ground using the same double-cone grinding wheel as grinding the helical surfaces of the worm. Based on the theory of gearing, the mathematical model for grinding relief surfaces is built. Motion parameters when grinding the different points of the land edges on different teeth of the hob are solved. A generating simulation is built by putting those motion parameters into a four-axis hourglass worm-grinding machine. The results of the simulation show that the relief surfaces can be ground continuously and the land widths and the relief angles meet the requirements.

Author(s):  
Rui Chengjie ◽  
Li Haitao ◽  
Yang Jie ◽  
Wei Wenjun ◽  
Dong Xuezhu

The relief surfaces of the cutting teeth of a dual-cone double enveloping hourglass worm gear hob cannot be ground automatically until now because all of teeth have different profiles and different spiral angles with each other. The land width and the relief angle of the hob are two important factors when using the hob to hob a worm gear. In order to improve the precision of this type worm pair, the land width and the relief angle of the hob need to be machined accurately and effectively. For the purpose that the land width and the relief angle could be machined precisely, an incomplete design and generating theory of the relief surfaces of the dual-cone double enveloping hourglass worm gear hob is put forward in this paper. The mathematical model of the incomplete design and generating theory of the relief grinding of the hob is built. According to the model, a series of data of the motion parameters when grinding different points of the land edges of the different hob teeth are solved out. Using those data of the motion parameters on a four-axis hourglass worm-grinding machine, a machining simulation is built and the results of the simulation show that the relief surfaces of the hob can be ground continuously, and the land width and the relief angle are consistent with the design.


Author(s):  
Q. Y. Shu ◽  
Q. Y. Qiu ◽  
P. E. Feng ◽  
L. Cao

The double enveloping hourglass worm gear pair is a type of transmission, which has many traits, such as more teeth in mesh for transmission, higher contact quality, better lubrication condition and so on. Therefore, it has higher efficiency of transmission, stronger bearing capacity and longer work life. But the manufacturing difficulty of the worm gear hob has limited its popularization and application. Unlike the traditional worm gear hob which can use the principle of optical projection to detect the hob shaft section and compare with its mathematical model, currently, there is no standard mathematical model to detect the shaft section of hourglass worm gear hob. Hence, the accuracy of hourglass worm gear hob can’t be guaranteed during manufacturing process, and the accuracy of hourglass worm gear can’t be guaranteed too. Thus, the transmission performance of the manufactured double enveloping hourglass worm gear pair will be affected. The paper puts forward a novel detection method for hourglass worm gear hob on the basis of the detecting method for traditional worm gear hob and established the mathematical model of the shaft section of hourglass worm gear hob. The manufacturing error of hourglass worm gear hob can be obtained through such detection. The paper also points out that the error is mainly produced during the grinding of hob teeth, because the grinding wheel is worn out and the blank hob is thermally deformed. At last, a method for error compensation is advanced during the process of hob grinding. The paper presents a test to verify the feasibility of this method and the test result shows that the manufacturing error of hourglass worm gear hob is reduced from 30.15μm to 10.3μm.


2009 ◽  
Vol 416 ◽  
pp. 524-528 ◽  
Author(s):  
Feng Shou Zhang ◽  
Feng Kui Cui ◽  
Chun Mei Li ◽  
Xiao Qiang Wang

The paper studies the grinding process of cold roller. The shape of grinding wheel, the arc radius of grinding wheel, the motion trajectory of wheel center and the grinding force are analyzed. The mathematical model is established. The cold rolling experiment shows that the analyses and formula deduced in this paper are correct. It provides theoretical basis for designing and manufacturing roller and provides the mathematical guidance for making process parameter and designing grinding machine.


Author(s):  
Yang Jie ◽  
Li Haitao ◽  
Rui Chengjie ◽  
Wei Wenjun ◽  
Dong Xuezhu

All of the cutting edges on an hourglass worm gear hob have different shapes and spiral angles. If the spiral angles are small, straight flutes are usually adopted. But for the hob with multiple threads, the absolute values of the negative rake angles at one side of the cutting teeth will greatly affect the cutting performance of the hob if straight flutes are still used. Therefore, spiral flutes are usually adopted to solve the problem. However, no method of determination of the spiral flute of the hourglass worm gear hob has been put forward till now. Based on the curved surface generating theory and the hourglass worm forming principle, a generating method for the spiral flute of the planar double enveloping worm gear hob is put forward in this paper. A mathematical model is built to generate the spiral flute. The rake angles of all cutting teeth of the hob are calculated. The laws of the rake angles of the cutting teeth of four hobs with different threads from one to four threads are analyzed when straight flutes and spiral flutes are adopted respectively. The laws between the value of the negative rake angles of the hob with four threads and the milling transmission ratio are studied. The most appropriate milling transmission ratio for generating the spiral flute is obtained. The machining of the spiral flutes is simulated by a virtual manufacturing system and the results verify the correctness of the method.


2009 ◽  
Vol 76-78 ◽  
pp. 61-66
Author(s):  
Ya Dong Gong ◽  
Yan Guang Bai ◽  
Yue Ming Liu ◽  
Jian Qiu

With the help of the infrared camera temperature measurement technology, the systemic theoretical analysis and experimental research for temperature field and thermal error distribution in NC grinding machine is provided. Two different situations for temperature field and thermal error distribution are respectively measured while the free and loaded grinding by the new measurement method. The mathematical model of thermal error is built, and it shows that the actual error and the forecasted error from thermal error mathematical model have good comparability.


2013 ◽  
Vol 652-654 ◽  
pp. 2153-2158
Author(s):  
Wu Ji Jiang ◽  
Jing Wei

Controlling the tooth errors induced by the variation of diameter of grinding wheel is the key problem in the process of ZC1 worm grinding. In this paper, the influence of tooth errors by d1, m and z1 as the grinding wheel diameter changes are analyzed based on the mathematical model of the grinding process. A new mathematical model and truing principle for the grinding wheel of ZC1 worm is presented. The shape grinding wheel truing of ZC1 worm is carried out according to the model. The validity and feasibility of the mathematical model is proved by case studies. The mathematical model presented in this paper provides a new method for reducing the tooth errors of ZC1 worm and it can meet the high-performance and high-precision requirements of ZC1 worm grinding.


2018 ◽  
Vol 1 (94) ◽  
pp. 27-34
Author(s):  
W. Stachurski ◽  
J. Sawicki ◽  
K. Krupanek ◽  
S. Midera

Purpose: The purpose of this article is to discuss the method of determining the mathematical model used for calculating the amount of emulsion reaching directly the grinding zone during the hob sharpening process. Design/methodology/approach: The mathematical model, in the form of a multiple regression function, was determined based on the acceptance and rejection method. The data for the calculations was obtained by conducting numerical simulations of fluid flow in the Ansys CFX software. Findings: A mathematical model enables calculating the amount of efficient expenditure of emulsion reaching directly the zone of contact between the grinding wheel and workpiece (hob cutter rake face) at various nozzle angle settings and different nominal expenditures of emulsion. The verification of the mathematical relationship confirmed its accuracy. Research limitations/implications: Further research should focus on the other types of grinding process and other types of cooling and lubricating fluids. Practical implications: The mathematical model enables a selection and application in the workshop and industrial practice of various variants of emulsion supply during the grinding of hob cutter rake face. Analysis of the multiple regression equation created on the basis of the acceptance and rejection method also allows predicting changes in the analyzed numerical model. Originality/value: The literature review has shown that no research of this type has been conducted with regard to analyses and optimisation of the grinding process during hob cutter sharpening. The results of this research are a novelty on a worldwide scale.


2010 ◽  
Vol 455 ◽  
pp. 132-136
Author(s):  
Xiao Zhong Ren ◽  
Ya Hui Wang ◽  
Jian Xin Su

Aiming at the dressing of involute grinding wheel, the mathematical model of involute interpolation is established. Taking the normal tolerance δ as accuracy index, the dense degree of interpolation points can be changed constantly with the change of developable angle increment △θ so that the numbers of interpolation points can meet the requirements not only for interpolating accuracy, but for interpolating efficiency. The wheel dressing software developed by using VC++ as programming tool can be applied for dressing the involute grinding wheel which can be used to grind involute gears with different teeth and modules. The results of simulation experiment verify the feasibility and correctness of the software.


2018 ◽  
Vol 764 ◽  
pp. 383-390 ◽  
Author(s):  
Quan Qi Xin ◽  
Tai Yong Wang ◽  
Zhi Qiang Yu ◽  
Hong Yan Hu

In this paper, the mathematical model of "S" - shaped cutting-edge curve is optimized, and the position and orientation of the grinding wheel of the first and second flank of the ball end milling cutter are calculated, The correctness of the algorithm is verified by VERICUT simulation.


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