Combining the loaded tooth contact analysis(LTCA)method and the gear dynamic model,a wear prediction model for spur gears with tip relief is established.The simulated wear depth is verified by the experimental results...Combining the loaded tooth contact analysis(LTCA)method and the gear dynamic model,a wear prediction model for spur gears with tip relief is established.The simulated wear depth is verified by the experimental results in a published reference.Based on the wear profile,the mesh stiffness and the tooth root stress obtained from the proposed model are compared with those obtained from the finite element model.Relative to the finite element method,the proposed method can greatly reduce the computation time.The effects of the tip relief and surface wear on the meshing and the dynamic characteristics are discussed.The tip relief can greatly decelerate the surface wear.Appropriate tip relief and slight wear can decrease the tooth interference and reduce the system vibration.Furthermore,the effects of the rotational speed on the wear depth are also studied and it is found that the quasi-static model is applicable to wear prediction when the rotational speed is away from the harmonic resonance peak.展开更多
Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root frac...Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root fracture.Tip relief and other gear profile modification have been considered for reducing the induced stresses in the gear tooth.In this work,the influence of tip relief on stresses on a pair of identical spur gear was analyzed using commercial FEA software ANSYS,and formulae for estimating contact and bending stresses were derived.Three cases of gear sets were analyzed;a non-modified pair and another two sets with linear and parabolic tip relief profiles.The non-modified gear set frictionless contact stress was validated against the calculated AGMA pitting resistance,Hertzian contact stress and a reported contact stress value in the literature.The four methods agreed well with each other.Similarly,bending stress was also compared with the AGMA bending strength and Lewis bending stress for validation.Then,friction coefficient was varied from 0.0 to 0.3 with increment of 0.1.The gear contact stress increased up to 11%relative to the frictionless case,whereas bending stress decreased by 6%.Linear tip relief modification was carried out for increasing normalised tip relief values of 0.25 to 1.0 with increment of 0.25.The gear frictionless contact and bending stresses decreased by a maximum of 4%and 2%,respectively.Frictional contact stress increased by up to 7.1%and the bending stress is almost identical with the frictionless case.Parabolic tip relief was also carried out with similar normalised tip relief values.Frictionless contact stress decreased by 5%while frictional contact stress increased by up to 11.5%and the bending stress is also almost identical with the frictionless case.Finally,four formulae were introduced for estimating the contact and bending stresses for a tip modified spur gear.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11772089)the Fundamental Research Funds for the Central Universities(Grant Nos.N170308028&N180708009)Program for the Innovative Talents of Higher Learning Institutions of Liaoning(Grant No.LR2017035)
文摘Combining the loaded tooth contact analysis(LTCA)method and the gear dynamic model,a wear prediction model for spur gears with tip relief is established.The simulated wear depth is verified by the experimental results in a published reference.Based on the wear profile,the mesh stiffness and the tooth root stress obtained from the proposed model are compared with those obtained from the finite element model.Relative to the finite element method,the proposed method can greatly reduce the computation time.The effects of the tip relief and surface wear on the meshing and the dynamic characteristics are discussed.The tip relief can greatly decelerate the surface wear.Appropriate tip relief and slight wear can decrease the tooth interference and reduce the system vibration.Furthermore,the effects of the rotational speed on the wear depth are also studied and it is found that the quasi-static model is applicable to wear prediction when the rotational speed is away from the harmonic resonance peak.
文摘Spur gears are widely used in the power transmission mechanism of several machines.Due to the transmitted torque,spur gears experience high stresses which could cause gear tooth failure by surface pitting or root fracture.Tip relief and other gear profile modification have been considered for reducing the induced stresses in the gear tooth.In this work,the influence of tip relief on stresses on a pair of identical spur gear was analyzed using commercial FEA software ANSYS,and formulae for estimating contact and bending stresses were derived.Three cases of gear sets were analyzed;a non-modified pair and another two sets with linear and parabolic tip relief profiles.The non-modified gear set frictionless contact stress was validated against the calculated AGMA pitting resistance,Hertzian contact stress and a reported contact stress value in the literature.The four methods agreed well with each other.Similarly,bending stress was also compared with the AGMA bending strength and Lewis bending stress for validation.Then,friction coefficient was varied from 0.0 to 0.3 with increment of 0.1.The gear contact stress increased up to 11%relative to the frictionless case,whereas bending stress decreased by 6%.Linear tip relief modification was carried out for increasing normalised tip relief values of 0.25 to 1.0 with increment of 0.25.The gear frictionless contact and bending stresses decreased by a maximum of 4%and 2%,respectively.Frictional contact stress increased by up to 7.1%and the bending stress is almost identical with the frictionless case.Parabolic tip relief was also carried out with similar normalised tip relief values.Frictionless contact stress decreased by 5%while frictional contact stress increased by up to 11.5%and the bending stress is also almost identical with the frictionless case.Finally,four formulae were introduced for estimating the contact and bending stresses for a tip modified spur gear.
