Tooth Surface Error Correction for Face-Hobbed Hypoid Gears

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Qi Fan
Keyword(s):  
Machine Tool ◽  
Machining Process ◽  
Tooth Surface ◽  
Surface Geometry ◽  
Premature Failure ◽  
Hypoid Gears ◽  
Surface Errors ◽  
The Face ◽  
Spiral Bevel ◽  
Universal Motion

Face-hobbing is a continuous generating process employed in manufacturing spiral bevel and hypoid gears. Due to machining dynamics and tolerances of machine tools, the exact tooth surface geometry may not be obtained from the machining process using theoretical machine tool settings. Repeatable tooth surface geometric errors may be observed. The tooth surface errors will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In order to eliminate the tooth surface errors and ensure precision products, a corrective machine setting technique is employed to modify the theoretical machine tool settings, compensating for the surface errors. This paper describes a method of correcting tooth surface errors for spiral bevel and hypoid gears generated by the face-hobbing process using computer numerically controlled hypoid gear generators. Polynomial representation of the universal motions of machine tool settings is considered. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth surface errors. The sensitivity of the changes of the tooth surface geometry to the changes of universal motion coefficients is investigated. A numerical example of a face-hobbed hypoid pinion is presented.

Tooth Surface Error Correction for Face-Hobbed Hypoid Gears

2009 ◽  
Author(s):  
Qi Fan
Keyword(s):  
Machine Tool ◽  
Machining Process ◽  
Tooth Surface ◽  
Surface Geometry ◽  
Premature Failure ◽  
Hypoid Gears ◽  
Transmission Errors ◽  
Surface Errors ◽  
Spiral Bevel ◽  
Universal Motion

Face-hobbing is a continuous generating process employed in manufacturing spiral bevel and hypoid gears. Due to machining dynamics and tolerances of machine tools, exact tooth surface geometry may not be obtained from the machining process using theoretical machine tool settings. Repeatable tooth surface geometric errors may be observed. The tooth surface errors will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In order to eliminate the tooth surface errors and ensure precision products, a corrective machine setting technique is employed to modify the theoretical machine tool settings, compensating for the surface errors. This paper describes a method of correcting tooth surface errors for spiral bevel and hypoid gears generated by face-hobbing process using computer numerically controlled (CNC) hypoid gear generators. Polynomial representation of the universal motions of machine tool settings is considered. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth surface errors. The sensitivity of the changes of tooth surface geometry to the changes of universal motion coefficients is investigated. A numerical example of a face-hobbed hypoid pinion is presented.

Optimization of Face Cone Element for Spiral Bevel and Hypoid Gears

2011 ◽  
Author(s):  
Qi Fan
Keyword(s):  
Tip Clearance ◽  
Tooth Surface ◽  
Root Tip ◽  
Tooth Root ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Hypoid Gears ◽  
Straight Line ◽  
The Face ◽  
Spiral Bevel

In the blank design of spiral bevel and hypoid gears, the face cone is defined as an imaginary cone tangent to the tops of the teeth. Traditionally, the face cone element or generatrix is a straight line. On the other hand, the tooth root lines which are traced by the blade tips are normally not straight lines. As a result, the tooth top geometry generally does not fit the mating member’s real root shape, providing an uneven tooth root-tip clearance; additionally, in some cases root-tip interference between the tooth tip and the root tooth surfaces of the mating gear members may be observed. To address this issue, this paper describes a method of determining an optimized face cone element for spiral bevel and hypoid gears. The method is based on the incorporation of calculation of tooth surface and root geometries, the conjugate relationship of the mating gear members, the ease-off topography, and the tooth contact analysis. The resulting face cone element may not be a straight line but generally an optimized curve that, in addition to avoidance of the interference, offers maximized contact ratio and even tooth root-tip clearance. Manufacturing of bevel gear blanks with a curved face cone element can be implemented by using computer numerically controlled (CNC) machines.

Higher-Order Tooth Flank Form Error Correction for Face-Milled Spiral Bevel and Hypoid Gears

2007 ◽  
Author(s):  
Qi Fan ◽  
Ronald S. DaFoe ◽  
John W. Swanger
Keyword(s):  
Higher Order ◽  
Hypoid Gear ◽  
Form Error ◽  
New Approach ◽  
Hypoid Gears ◽  
Form Errors ◽  
The Face ◽  
Spiral Bevel ◽  
Universal Motion ◽  
Tooth Flank

The increasing demand for low noise and high strength leads to higher quality requirements in manufacturing spiral bevel and hypoid gears. Due to heat treatment distortions, machine tolerances, variation of cutting forces and other unpredictable factors, the real tooth flank form geometry may deviate from the theoretical or master target geometry. This will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In the hypoid gear development process, a corrective machine setting technique is usually employed to modify the machine settings, compensating for the tooth flank form errors. Existing published works described the corrective machine setting technique based on the use of mechanical hypoid gear generators, and the second order approximation of error surfaces. Today, Computer Numerically Controlled (CNC) hypoid gear generators have been widely employed by the gear industry. The Universal Motion Concept (UMC) has been implemented on most CNC hypoid generators, providing additional freedoms for the corrections of tooth flank form errors. Higher order components of the error surfaces may be corrected by using the higher order universal motions. This paper describes a new method of tooth flank form error correction utilizing the universal motions for spiral bevel and hypoid gears produced by the face-milling process. The sensitivity of the changes of tooth flank form geometry to the changes of universal motion coefficients is investigated. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth flank form errors. A numerical example of a face-mill completing process is presented. The developed new approach has been implemented with computer software. The new approach can also be applied to the face-hobbing process.

Computerized Modeling and Simulation of Spiral Bevel and Hypoid Gears Manufactured by Gleason Face Hobbing Process

2005 ◽  
Vol 128 (6) ◽  
pp. 1315-1327 ◽  
Author(s):  
Qi Fan
Keyword(s):  
Modeling And Simulation ◽  
Surface Generation ◽  
Tooth Surface ◽  
Generation Model ◽  
Tooth Contact Analysis ◽  
Hypoid Gears ◽  
Left Hand ◽  
The Face ◽  
Blade Edge ◽  
Spiral Bevel

The Gleason face hobbing process has been widely applied by the gear industry. But so far, few papers have been found regarding exact modeling and simulation of the tooth surface generations and tooth contact analysis (TCA) of face hobbed spiral bevel and hypoid gear sets. This paper presents the generalized theory of the face hobbing generation method, mathematic models of tooth surface generations, and the simulation of meshing of face hobbed spiral bevel and hypoid gears. The face hobbing indexing motion is described and visualized. A generalized description of the cutting blades is introduced by considering four sections of the blade edge geometry. A kinematical model is developed and analyzed by breaking down the machine tool settings and the relative motions of the machine elemental units and applying coordinate transformations of the elemental motions. The developed face hobbing generation model is directly related to a physical bevel gear generator. A generalized and enhanced TCA algorithm is proposed. The face hobbing process has two categories, non-generated (Formate®) and generated methods, applied to the tooth surface generation of the gear. In both categories, the pinion is always finished with the generated method. The developed tooth surface generation model covers both categories with left-hand and right-hand members. Based upon the developed theory, an advanced tooth surface generation and TCA program is developed and integrated into Gleason CAGE™for Windows Software. Two numerical examples are provided to illustrate the implementation of the developed mathematic models.

Manufacture of Optimized Face-Hobbed Spiral Bevel Gears on Computer Numerical Control Hypoid Generator

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Vilmos V. Simon
Keyword(s):  
Machine Tool ◽  
Angular Displacement ◽  
Transmission Error ◽  
Numerical Control ◽  
Tooth Surface ◽  
Surface Geometry ◽  
Tooth Contact ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel

In this study, a method is proposed for the advanced manufacture of face-hobbed spiral bevel gears on CNC hypoid generators with optimized tooth surface geometry. An optimization methodology is applied to systematically define optimal head-cutter geometry and machine tool settings to introduce optimal tooth modifications. The goal of the optimization is to simultaneously minimize tooth contact pressures and angular displacement error of the driven gear (the transmission error). The optimization is based on machine tool setting variation on the cradle-type generator conducted by optimal polynomial functions. An algorithm is developed for the execution of motions on the CNC hypoid generator using the relations on the cradle-type machine. Effectiveness of the method was demonstrated by using a face-hobbed spiral bevel gear example. Significant reductions in the maximum tooth contact pressure and in the transmission errors were obtained.

Optimization of Face Cone Element for Spiral Bevel and Hypoid Gears

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Qi Fan
Keyword(s):  
Tip Clearance ◽  
Tooth Surface ◽  
Root Tip ◽  
Tooth Root ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Hypoid Gears ◽  
Straight Line ◽  
The Face ◽  
Spiral Bevel

In the blank design of spiral bevel and hypoid gears, the face cone is defined as an imaginary cone tangent to the tops of the teeth. Traditionally, the face cone element or generatrix is a straight line. On the other hand, the tooth root lines, which are traced by the blade tips, are normally not straight lines. As a result, the tooth top geometry generally does not fit the mating member’s real root shape, providing an uneven tooth root-tip clearance; additionally, in some cases root-tip interference between the tooth tip and the root tooth surfaces of the mating gear members may be observed. To address this issue, this paper describes a method of determining an optimized face cone element for spiral bevel and hypoid gears. The method is based on the incorporation of calculation of tooth surface and root geometries, the conjugate relationship of the mating gear members, the ease-off topography, and the tooth contact analysis. The resulting face cone element may not be a straight line but generally an optimized curve that, in addition, to avoidance of the interference, offers maximized contact ratio and even tooth root-tip clearance. Manufacturing of bevel gear blanks with a curved face cone element can be implemented by using computer numerically controlled machines.

Higher-Order Tooth Flank Form Error Correction for Face-Milled Spiral Bevel and Hypoid Gears

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
Qi Fan ◽  
Ronald S. DaFoe ◽  
John W. Swanger
Keyword(s):  
Higher Order ◽  
Hypoid Gear ◽  
Form Error ◽  
New Approach ◽  
Hypoid Gears ◽  
Form Errors ◽  
The Face ◽  
Spiral Bevel ◽  
Universal Motion ◽  
Tooth Flank

The increasing demand for low noise and high strength leads to higher quality requirements in manufacturing spiral bevel and hypoid gears. Due to heat treatment distortions, machine tolerances, variation of cutting forces, and other unpredictable factors, the real tooth flank form geometry may deviate from the theoretical or master target geometry. This will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In the hypoid gear development process, a corrective machine setting technique is usually employed to modify the machine settings, compensating for the tooth flank form errors. Existing published works described the corrective machine setting technique based on the use of mechanical hypoid gear generators, and the second-order approximation of error surfaces. Today, computer numerically controlled (CNC) hypoid gear generators have been widely employed by the gear industry. The universal motion concept has been implemented on most CNC hypoid generators, providing additional freedoms for the corrections of tooth flank form errors. Higher-order components of the error surfaces may be corrected by using the higher-order universal motions. This paper describes a new method of tooth flank form error correction utilizing the universal motions for spiral bevel and hypoid gears produced by the face-milling process. The sensitivity of the changes of tooth flank form geometry to the changes of universal motion coefficients is investigated. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth flank form errors. A numerical example of a face-mill completing process is presented. The developed new approach has been implemented with computer software. The new approach can also be applied to the face-hobbing process.

New Geometry of Generating Spiral Bevel Gear

2007 ◽  
Author(s):  
Kaihong Zhou ◽  
Jinyuan Tang ◽  
Tao Zeng
Keyword(s):  
Gear Tooth ◽  
Previous Method ◽  
Bevel Gear ◽  
Tooth Surface ◽  
Spiral Bevel Gear ◽  
Surface Geometry ◽  
Numerical Examples ◽  
Cone Surface ◽  
Spiral Bevel ◽  
Involute Curve

New geometry of generating spiral bevel gear is proposed. The key idea of the new proposed geometry is that the gear tooth surface geometry can be investigated in a developed curved surface based on the planar engagement principle. It is proved that the profile curve on the back of generating cone surface is a conical involute curve. The equations of generated gear tooth surface are achieved by the conical involute curve sweeping along the tooth trace of gear. The obtained equations are explicit and independent of the machine-tool settings. This differs from previous studies. The developed theory is illustrated with numerical examples to compare with the previous method, the comparison approves that the method is possible in this way. The new method indicates that there are new solutions to the design the production of spiral bevel gear.

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