Study on the optimum standard parameters of hob optimization for reducing gear tooth root stress

2021 ◽  
Vol 156 ◽  
pp. 104128
Author(s):  
Rong He ◽  
Peter Tenberge ◽  
Xiangyang Xu ◽  
Hongwu Li ◽  
Ray Uelpenich ◽  
...  
1997 ◽  
Vol 119 (4) ◽  
pp. 518-521 ◽  
Author(s):  
L. Fredette ◽  
M. Brown

This paper discusses research into the possibility of reducing gear tooth root stresses by adding internal stress relief features. For many years, gear designs have improved with the incremental addition of design features. Materials have improved, surfaces are selectively hardened with heat treatment and carborization, and shot peening is used to improve surface properties. All of these improvements are related to material attributes. Little has been done to change the gear geometry to improve durability and strength. Although the exterior of the gear is governed by the necessary involute profile of the teeth, nothing prevents interior changes. In this study holes were drilled along the axis of a test gear segment in an effort to provide stress relief in critical areas. A finite element model was constructed for use in a systematic test of the effect of hole size and hole placement on tooth root stress. A constant force was applied at the pitch diameter, and all results were normalized with respect to the values obtained for a solid gear. Results show that it is possible to reduce the tooth root tensile stress considerably without producing stresses in the holes greater than on an unmodified gear. These results were verified by photoelastic testing on greatly oversized plastic models. Since gear teeth fail due to fatigue over many cycles, even a slight reduction in the root tensile stress produces a great increase in fatigue life.


Author(s):  
Jean-Pierre de Vaujany ◽  
Miche`le Guingand ◽  
Didier Remond

The main objective of this study is to quantify the influence of the deformation of the rim of an internal gear on the meshing stiffness and the stress distribution in tooth fillets. The 3D model used is based on a method derived from the Finite Prism Method. Tooth bending effects and contact deformations are processed simultaneously. Scientific use of the software has resulted in formulating an equation to calculate the maximal tension stress in the tooth root. This formula has been obtained by using the statistical design of experiment method.


2021 ◽  
Vol 166 ◽  
pp. 104496
Author(s):  
Luca Landi ◽  
Alessandro Stecconi ◽  
Giulia Morettini ◽  
Filippo Cianetti

2013 ◽  
Vol 278-280 ◽  
pp. 139-142
Author(s):  
Xiang Bian ◽  
Zong De Fang ◽  
Kun Qin ◽  
Lifei Lian ◽  
Bao Yu Zhang

Usually the gear modification is a main measure to reduce the vibration and noise of the gears, but in view of the complexity of the gear modification, topology optimization method was used to optimize the structure of the gear. The minimum volume was set as the direct optimization goal. To achieve the target of reducing contact stress, tooth root bending stress and improving flexibility, the upper bound of the stress and lower bound of the flexibility were set appropriately, thus realizing multi-objective optimization indirectly. A method for converting topology result into parametric CAD model which can be modified was presented, by fitting the topology result with simple straight lines and arcs, the model can be smoothed automatically, after further regulating, the geometry reconstruction was finished. After topology optimization, the resulting structure and properties of the gear are consistent with cavity gear. While reducing the weight of the gear, the noise can be reduced and its life would be extended through increasing flexibility and reducing tooth root stress.


Author(s):  
Gong Donghui ◽  
Ichiro Moriwaki ◽  
Kenji Saito

Abstract Although thermoplastic poly-imide (TPI) gears do not have sufficient strength for power transmission, carbon fiber reinforcement greatly improves the strength of TPI gears. Previous experimental research showed that although standard specimens made from carbon fiber reinforced (CFR) TPI has 2.4 times strength in static bending than specimens made from natural TPI, gears made from CFR-TPI yields bending fatigue strength about 10 times greater than gears made from natural TPI. The present paper explains this phenomenon using viscoelastic tooth root stress analysis. The experiments indicated that the natural TPI gears showed much larger viscoelasticity than the CFR-TPI gears. Thus, tooth root stresses were calculated for cases of large and small viscosity moduli. These calculations showed tooth root stress increased with the increase in the viscosity modulus. Also, viscoelasticity may induce heat due to hysteresis loss, and this heat should reduce gear durability. The increase in tooth root stress and the heat due to hysteresis loss must make the durability of the natural TPI gears very small. Therefore, the CFR-TPI can yield much more durable gears than the natural TPI.


Author(s):  
Carlos H. Wink

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.


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