Gearbox Pump Control Using Differential Speed for Lubrication
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Solution Overview
Problem
Current wind turbine gearbox systems face challenges with insufficient lubrication due to low-speed operation of mechanical pumps, leading to potential oil leakage and increased energy consumption when displacement is designed for rated conditions, and insufficient lubrication at low input speeds.
Innovation Solution
A control device comprising a sensor module, differential, clutch, and brake system that adjusts the rotation speed of mechanical and electric pumps based on system oil pressure thresholds, using a two-position four-way valve to actuate the brake and clutch, allowing the mechanical pump to adapt to different operating conditions and ensure adequate lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the displacement of the mechanical pump is designed based on rated load and rated speed, then the pump can meet lubrication requirements at rated conditions, but at low input speeds the pump rotation speed is too low and insufficient oil supply occurs
Solution Approach 1:
The patent applies a differential mechanism to dynamically adjust the mechanical pump's rotation speed. The differential converts the single-speed input from the gearbox output shaft into two different output speeds: one for the clutch (same as input speed) and another for the mechanical pump (double the input speed). This dynamic speed multiplication ensures that at low gearbox input speeds, the mechanical pump still rotates fast enough to provide sufficient oil supply for reliable lubrication.
2Productivity
If the displacement of the mechanical pump is designed based on low input rotation speed, then sufficient oil supply is provided at low speeds, but under rated operating conditions excessive flow occurs causing high oil pressure and increased energy consumption
Solution Approach 1:
The differential mechanism dynamically adjusts the mechanical pump's rotation speed based on operating conditions. At rated operating conditions, the gearbox output shaft rotates at high speed, which through the differential mechanism results in the mechanical pump rotating at double this high speed. However, the clutch engages to redirect power, causing the mechanical pump to rotate at the same speed as the differential housing rather than double speed, thereby reducing excessive flow and energy consumption at rated conditions.
3Reliability
If the mechanical pump is primarily responsive at low temperatures with low electric pump operation, then the mechanical pump must handle all circulation, but this leads to insufficient lubrication at low input speeds
Solution Approach 1:
The differential mechanism provides dynamic speed adjustment capability that allows the mechanical pump to operate effectively across a wide range of input speeds. At low temperatures when the electric pump is not activated, the mechanical pump's enhanced rotation speed (double the input speed) ensures it can handle all circulation requirements reliably. The system maintains operational flexibility by enabling the mechanical pump to adapt to varying speed requirements without requiring constant electric pump intervention.
Data Source
AI summary
A control device for a gearbox which includes a mechanical pump and an electric pump, the control device including a sensor module configured to detect a system oil pressure of a lubricating oil of the gearbox, a differential, a clutch, a brake, and a control module. The differential includes an input bevel gear meshing with a bevel pinion of an output shaft of the gearbox, a differential housing connected to the input bevel gear, and a first half shaft and a second half shaft which are provided in the differential housing and mesh with a bevel pinion of the differential housing. The second half shaft is connected to an input of the mechanical pump. The brake includes a brake caliper, a brake disc, and a brake disc shaft fixedly connected to the brake disc. The brake disc shaft is fixedly connected to the first half shaft.