Drive-Drive Gear Pump Torque Synchronization for Tooth Wear Control
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Solution Overview
Problem
Conventional drive-drive gear pumps face inefficiencies and premature wear due to variations in gear tooth dimensions and operating conditions, leading to inconsistent contact forces and potential failure, especially at varying temperatures and pressures.
Innovation Solution
A control system that dynamically synchronizes torque and position between meshing gear teeth using feedback signals from the fluid system and motor parameters to maintain predetermined setpoints, adjusting motor demands to ensure consistent contact forces and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive-drive system is configured to operate in a variety of operating conditions, designing for the worst-case scenario, then the system can handle worst-case stresses, but the drive-drive pump may not be efficient at normal operating conditions and/or may not have the most economical construction
Solution Approach 1:
The patent applies dynamics by making the speed differential adjustable rather than fixed. The control system dynamically modifies the speed differential between the two drive motors based on operating conditions, allowing the system to optimize contact force for both normal and worst-case scenarios. This resolves the contradiction by enabling the system to adapt its configuration rather than being locked into a worst-case design that compromises normal efficiency.
Solution Approach 2:
The patent changes the parameter of speed differential dynamically. By adjusting the speed differential between the two drives based on operating conditions (flow, pressure, temperature), the system can optimize gear contact force for each scenario. This allows efficient operation at normal conditions while maintaining the capability to handle worst-case stresses, eliminating the need to always design for worst-case.
2Productivity
If the drive-drive system is set such that an appropriate contact force for normal operating conditions, then the contact force may not be sufficient during worst-case scenarios to maintain proper operation and/or efficiency
Solution Approach 1:
The system transitions from a static speed differential setting to a dynamic one. The control system continuously monitors operating conditions and adjusts the speed differential accordingly, ensuring adequate contact force during worst-case scenarios while maintaining optimal efficiency during normal operation.
Solution Approach 2:
The patent implements feedback control where the control system monitors operating parameters (flow, pressure, temperature) and uses this information to adjust the speed differential. This feedback mechanism ensures that contact force remains appropriate for current conditions, preventing both insufficient contact force during worst-case scenarios and excessive contact force during normal operation.
3Reliability
If the gears are manufactured to tight tolerances to minimize the variation in the contact force, then the variation in contact force is reduced, but the cost of the systems rises
Solution Approach 1:
The patent replaces the mechanical solution of tight gear tolerances with a control system solution. Instead of relying on precision manufacturing to minimize contact force variation, the system uses active control of the speed differential to maintain consistent contact force. This substitution allows the use of more economical manufacturing tolerances while achieving the same reliability outcome.
Solution Approach 2:
The patent changes the approach from static parameter control (fixed tolerances) to dynamic parameter control (adjustable speed differential). By actively modifying the speed differential based on operating conditions, the system compensates for gear tooth variations without requiring tight manufacturing tolerances, thereby reducing manufacturing costs while maintaining consistent contact force.
Data Source
AI summary
An apparatus includes a torque adjustment circuit to receive a torque setpoint and a torque feedback signal corresponding to a differential torque between a pair of meshing gear teeth of a first gear and a second gear. The torque adjustment circuit is further configured to output a torque adjustment signal corresponding to a difference between the torque setpoint and the torque feedback signal. The apparatus also includes a motion control circuit to provide a first speed demand signal to a first motor that drives the first gear and a second demand signal to a second motor that drives the second gear, and dynamically synchronize torque between the pair of meshing gear teeth such that the differential torque between the pair of meshing gear teeth is within a predetermined range by adjusting at least one of the first speed demand signal or the second speed demand signal.