Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

Abstract

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

Dynamic analysis of involute spur gears with asymmetric teeth

“…This result may be due to the narrow single contact zone. As discussed in detail by Liou et al [25], because of the narrow single contact zone, this zone is passed quickly as the gear rotates such that the system can not respond. The variation of single contact zone with contact ratio can be seen in Fig.…”

“…[15,[17][18][19][20] can be extended to spur gears with asymmetric teeth. So far, the influence of these parameters on dynamic analysis has only been investigated for gears with symmetric teeth by several researchers [20][21][22][23][24][25].…”

Piecewise model and estimates of damping and natural frequency for a spur gear

“…Modern gear dynamical models [1][2][3][4][5][6][7][8] are time varying due to the time varying mesh stiffness and static transmission error. For obtaining the approximate analytical solution of the time-varying gear equation most of the investigators used the harmonic balance method [2,4].…”

A Lightweight Model for Gear Mesh Dynamics Incorporating Variable Mesh Stiffness

“…The study of gear vibration has traditionally treated problems such as the determination of the primary resonant speeds of given gear mechanisms, or calculating the corresponding load factors [1][2][3][4][5]. However these models are typically either too simplistic in terms of how stiffness is modelled, or employ complex FEA analysis that is resource intensive.…”