Papers by Author: Chao Lin

Abstract: Oval bevel gear is introduced as a new gear transmission type of intersecting axes, in which high-order, denaturing and eccentric one are included. Based on the theory of spatial engagement, spatial spherical coordinate system of the noncircular bevel gearing was developed and a generalized tooth profile equation of noncircular bevel gears was also proposed. The gear profile can be enveloped for the generating movement between conical cutter and oval bevel gear according to the envelope principle of conjugate profiles. Then a new and general parametric design method for oval bevel gear was founded. The classification and gear variability condition of oval bevel gear were discussed. Meanwhile, its pitch curve, addendum and dedendum curve were studied, and the corresponding equations were deduced. A roll check experiment is performed on the prototype workpiece. Then the influences of motor speed and load on transmission ratio were analyzed. Finally, the design method, profile generation method and manufacture method of oval bevel gear were certified as correct by comparing experimental curve of transmission ratio with theoretical one.

Abstract: On the basis of geometrical characteristic of the mirco/nano-transmission platform(MNTP), its kinematics model and input/output motion are established by the theory of coordinate transformation. The stiffness model was derived using elasto-dynamics and Lagrange equation. In terms of ANSYS, the output displacement and stiffness of different degrees of freedom(DOF) was simulated. Actual output displacement about x axis and stiffness along z axis were obtained by experimental testing, the results of them obtained by theoretical computation, ANSYS simulation and testing were compared. A good agreement was achieved, which shows that the kinematics model, stiffness model, the design principle and experiments of the MNTP are correct.

Abstract: Aiming at the complex design and analysis methods of noncircular bevel gear, combining the gear space engagement theory and the generating method of tooth profile, the profile generating process was seen as the pure rolling between the pitch line of virtual processing tool and pitch curve of oval bevel gear based on the virtual generating method. The blank parameters and relation equation between tool parameters and procedure parameters of generating method were deduced. General parametric solid models of oval bevel gear were founded. Based on experimental result of oval bevel gear transmission, the design profile of oval bevel gear which was obtained according to generating method was verified.

Abstract: This paper makes the emulate experimental research of cutting force in high-speed dry gear milling by flying cutter with finite element analysis method by using the established cutting force model yet, makes the comparative analysis for the result of simulation experiment and theoretical calculation, verifies the correctness of cutting force model and calculation method, makes the comparative analysis for the influencing relations and changing laws of cutting force and cutting parameters and so many factors, and reveals the cutting mechanism of high-speed dry gear milling by flying cutter initially. By the research of this paper, it provides basic theory for subsequent cutting machine technology of high-speed dry gear hobbing, and establishes the theoretical basis for the spread and exploitation of this technology.

Abstract: The purpose of this paper was to generate several possible configurations of micro/nano-positioning stage with bridge-type mechanism based on graph theory. The structural characteristics of stage were discussed first. Then, these modules made up of micro/nano-positioning stage were abstracted. Thus the stage could be described with a tree-graph. According to the spanning tree theory, several possible configurations of stage are enumerated correspondingly. Subsequently, the configuration synthesis of six bridge-type mechanisms was investigated and 720 results were obtained. Rules for generating structures with symmetry are established. On the basis of this, several innovative structures are presented. Furthermore, the result of this paper provides a practicable approach for the structural design of stage and the design method based on graph theory is effective.

Abstract: This paper presents a simulation approach for estimating the trajectory error of a linear interpolation cutter path produced by the numerical control Acc/Dec motion characteristics for a MC. The algorithm is very simple and efficient for simulation calculation. Through comparing the machined profiles of workpiece with the calculated cutter path trajectories, the effectiveness of the proposed approach is sufficiently demonstrated.

Abstract: The dual-drive system to be used in the tunnel boring machine (TBM) is a new kind of high-power planetary transmission system. On the basis of the system’s transmission theory and the bond graph principle, the bond graph model of the dual drive transmission system is established and then the state equations are deduced. Based on this model, dynamic performance of the system is simulated by means of MATLAB/Simulink and the dynamic response curves of the speed and torques are acquired. The simulation response illustrates that the bond graph model of dual drive transmission systems is accurate. In addition this system is suitable for three types of TBM and can satisfy the requirements of dramatic changes of load in the running of TBM.

Abstract: This paper proposes an optimal interpolation approach to generate cutter paths in the form of polar coordinate for machining noncircular contours. The cutter path obtained with the approach consists of a series of Archimedes’ spiral segments and the number of segments is the fewest under the condition that the interpolation error completely satisfies the specified limit value. It can be also evidenced that the profile error of the machined contour due to the cutter path is perfectly controlled within the specified interpolation accuracy limit. The result of applying the approach to the contour machining of a disc cam sufficiently illustrates the effectiveness of the proposed approach.