AGMA 04FTM3-2004 pdf free download.Method to Define Profile Modification of Spur Gear and Minimize the Transmission Error.
In a gear set, Transmission Error (TE) is defined as the difference between the effective and the ideal position of the output shaft with reference to the input shaft. The ideal position represents a condition of perfect gear box, without geometrical errors and deflections. TE can be expressed either by an angular displacement or, more conveniently, as a linear displacement measured along a line of action at base circle according to [1]. TE is typically considered to be the primary cause of whining noise.
Indeed, whining noise is produced by:
changing tooth load amplitude,
— changing load position along the tooth profile,
— changing tooth load direction.
These changes are consequences of tooth deflection, local contact deformation and body deformation quantities, which are the origin of TE Several Authors [2-61 studied the correlation between TE and profile modification, in order to reduce the TE Niemann [4] proposed long and short modifications.
This different denomination is based on the start point of tip relief modification along the profile.
According to experimental results, gears with long modification have the minimum PPTE and the minimum noise level at the design torque. At lower torque this optimum condition was not venfied and an intermediate or short modification is suggested. In these works short and long modifications are considered to be technological limits and it is not useful to extend the relief to the pitch radius, as described in [1,3].
In the present paper, instead, the start tip relief modifications (Os,. OG) have been considered as design variables ranging from Start Active Profile roll angle (SAP) up to the End Active Profile roll angle (EAP). Total relief v9 (at the tooth tip) is imposed equal to the deflection of tooth pairs under the nominal torque. The topography of the tip relief is parabolic. The conditions for obtaining the minimum PPTE configuration are found and discussed.
2 Methodology
The quantities i’,” (v””) and O (Os) are defined in figure 1.
The ranges for the two Roll Angle variables are the Start Active Profile roll angle (SAP) and the End Active Profile roll angle (&1P) for each gear (figure 2).
Meshing gears simulations have been carried out by means of a hybrid method, combining the Finite Element technique with a semi-analytical solution [7.8].AGMA 04FTM3 pdf download.