| The jumping robot has strong obstacle jumping ability,which makes it have a great prospect in rubble search and rescue,battlefield detection,archaeological exploration and other occasions.With the development of science and technology,the demand for transmission efficiency and carrying capacity of the jumping robot is increasing.The research of the high-performance gear suitable for the jumping robot transmission system is an important direction.In nature,the Issus planthopper has a pair of gears in its hip joint,which enables the planthopper’s legs to be highly synchronized and has the characteristics of high transmission efficiency and high output torque.The gear meets the demand of high performance gear for jumping robot.Therefore,a new type of bionic gear is designed referring to the characteristics of the planthopper gear tooth profile and curve characteristics in this thesis.The meshing principle,sliding characteristics and tooth profile interference conditions of the bionic gear are analyzed,and the transmission efficiency,error and strength of the gear are calculated.The main contents are as follows.(1)The transmission occasions and characteristics of the planthopper gear are analyzed according to the planthopper hopping process.The results show that the planthopper gear is suitable for high speed,high precision and high power density,and has the characteristics of low transmission error,high transmission efficiency and pure rolling contact.Since the tooth profiles of the planthopper gear are naturally generated and the logarithmic helix is also a natural curve,the working tooth profiles of the planthopper gear are assumed to be logarithmic helix.The feasibility of logarithmic helices as gear tooth profile is analyzed.The the planthopper working tooth profiles are extracted by edge detection method and fitted with logarithmic helix.Then,the tooth profiles of the bionic gear are constructed,the tooth profiles parameters formulas are derived,and the tooth profiles curve equations are established.(2)According to the indirect conjugation principle,the equations of the bionic gear teeth surfaces,their working lines,and contact lines are all derived.The gear pure rolling conditions are established,the gear overlap ratio and transverse contact ratio are analyzed,and the gear meshing principle is revealed.According to the geometric relation,kinematic method and the gear relative motion principle,the conditions of the gear does not have static interference,root cutting and dynamic interference are obtained.The center distance error influence on the gear sliding characteristics is studied.Then,the bionic gear interference is analyzed with examples and meshing principle is verified.(3)The bionic gear dynamic transmission simulation shows that the bionic gear has high transmission efficiency and small transmission error.Based on the differential geometry theory and Hertz contact theory,the teeth surfaces contact stress formula of the bionic gear is derived.The contact curve length parameter in the formula is solved by the finite element simulation method,and the formula correctness is verified.According to the cross-section method,The gear bending stress mathematical model is established.By using the finite element simulation method,the stress correction parameter in the mathematical model is obtained and the mathematical model correctness is verified.The gear finite element simulation results are compared with that of the involute helical gear and pure rolling single arc gear.As a result,the bionic gear behaviors high contact strength and superior process versatility,which provides an effective basis for the bionic gear to realize engineering application. |
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