Deng Xiaozhong

Study on the CNC internal gear form grinding technology

Gear grinding is widely used for finishing gears with hard face. Gear form grinding has many advantages over gear generation grinding. The form grinding accuracy depends on the form wheel dressing technology to a great extent. In order to ensure the tooth profile accuracy, a kind of form wheel dressing device by using diamond wheel as dressing tool is developed. Based on the involute interpolating principle, the NC program for form wheel dressing is prepared, and the dressing motion is controlled by NC controller. It is also very important for gear teeth to be evenly distributed in a circle so as to reduce pitch error. A kind of gear grinding method named jumping division is proposed in order to improve tooth division accuracy, and CNC gear grinding program is also developed. The grinding wheel dressing experiment and gear grinding test are carried out on the autonomous developed CNC internal gear grinding machine. Internal gear grinding experiment validates the grinding technology proposed in this article.

Meshing Performance Analysis of Spiral Bevel Gears Based on Assembly Misalignment

The influence of different assembly misalignment on the meshing performance of spiral bevel gears was studied. Based on the principle of local synthesis, the meshing model of spiral bevel gears is established. The tooth contact analysis of spiral bevel gears is introduced. Taking a pair of spiral bevel gears as an example, the influence of assembly misalignment on the meshing performance of gears was studied in the range of error variation. The research results are of great significance for the rapid determination of the optimal installation distance of spiral bevel gears. Introduction Spiral bevel gears are widely used in the field of Aeronautics and Astronautics as a kind of key transmission component because of its high coincidence and stable transmission. In the practical application of engineering, the meshing position of spiral bevel gears can not reach the ideal state due to machining error, assembly misalignment and support deformation, and there will always be some transmission error. Transmission error can affect the meshing performance of gear, resulting in poor tooth contact, vibration, reduction of transmission stability, and assembly misalignment is the key factors affecting the transmission error of spiral bevel gears. Prof. Zhonghou Wang [1] put forward a tooth contact analysis (TCA) method based on high precision digital real tooth surface of spiral bevel gears. The feasibility and effectiveness of this method can be verified through the comparison of TCA software analysis results by Gleason corporation and tooth wear test results. Prof. Guanglei Liu [2] proposed a generally modified-roll (GMR) as an improved method of the traditional local synthesis for the optimization of the transmission error function of spiral bevel gears in comparison with the desired curve. Prof. JinFu Du [3] proposed the digital gear surfaces that exactly approximate real tooth surfaces are obtained by fitting the measured discrete points with non-uniform rational B-spline (NURBS) curve. A tooth contact analysis (TCA) of digital gear surfaces is carried out and the feasibility of the proposed method is verified through a comparison between digital gear surface TCA and rolling test of a high-speed axle gear pair. Prof. Zongde Fang [4] provided tooth contact analysis algorithm with consideration of alignment errors. Taking a pair of spiral bevel gears as an example, the feasibility of tolerance optimization method was verified by comparing the meshing and transmission errors before and after optimization. Prof. Yaobin Zhuo [5] presented a method for the global optimization of the tooth contact pattern and transmission error of spiral bevel and hypoid gears, and a finite element model of a simplified hypoid gear drive system is established and its quasi-static meshing characteristics analyzed. Suitable contact area meeting design requirements is a common method of evaluating meshing performance, but the evaluation of spiral bevel gears meshing performance also need to refer to transmission error curve. The research on the influence of assembly misalignment on gear meshing performance has seldom mentioned the range of variation of assembly misalignment at home and This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Copyright

Deviation and correction of tooth surface for spiral bevel gears

Theoretical gear calculations and coordinate measuring machines have been combined to provide an objective, quantitative method for inspecting bevel gears. Errors between the actual surface and the theoretical surface are measured in this way. Changes in the cutting or grinding machine setup are required to bring the errors within an acceptable tolerance. The deviations of the real tooth surfaces from the theoretical one is determined by measuring date processing. A general surface can be expressed in terms of a polynomial and subdivided by rank into first, second and progressively higher orders. The sensitivity of these first and second order terms for the changes of machine settings is analyzed. The corrective machine setting was developed using this concept. The proposed ideas are proven by grinding the convex flank of gear for a pair of spiral bevel gears; the cutting machine settings are adjusted for twice and bring the errors within an acceptable tolerance. This paper presents a method for adjusting the cutting machine settings and provides an effective method of improving designing level, quality of products.