Tribo-Dynamics of Dual-Star Planetary Gear Systems: Modeling, Analysis, and Experiments

Area of Science:

• Mechanical Engineering
• Tribology
• Lubrication Science

Background:

• Planetary gear systems are crucial in many applications.
• The interaction between lubrication and dynamics in these systems is not fully understood.
• Existing models often neglect thermal elastohydrodynamic lubrication (TEHL) effects.

Purpose of the Study:

• To develop a novel tribo-dynamic model for dual-star planetary gears.
• To investigate the coupling mechanism between TEHL and dynamic behaviors.
• To provide insights for designing high-reliability planetary gear systems.

Main Methods:

• Established a TEHL surrogate model to calculate oil film thickness and friction.
• Developed a dynamic model of the dual-star planetary gear system using coordinate transformations.
• Integrated lubrication effects into time-varying mesh stiffness and backlash.

Main Results:

• Lubricant film thickness increases with relative sliding velocity and decreases with unit line load.
• A thicker oil film under high-speed conditions can cause premature meshing contact and impacts.
• Under high-torque conditions, tooth deformation is the primary driver of force fluctuations.

Conclusions:

• The developed tribo-dynamic model accurately captures the complex interactions in planetary gears.
• Lubrication plays a significant role in gear dynamics, especially under high-speed operation.
• The findings offer valuable theoretical and experimental support for the design of reliable planetary gear systems.