Top Drive Motor Decoupling with Single-Oil Gearbox Lubrication
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Solution Overview
Problem
Existing top drive systems require separate oil compartments for decoupling and coupling, leading to maintenance challenges and risks of oil leakage, which can cause overheating.
Innovation Solution
A top drive system with a gearbox and traction motor where the traction motor can be decoupled from the spindle using a pinion shaft assembly with a quick disconnect feature, allowing torque transfer when engaged and none when disengaged, all within a single gear oil compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate oil compartment is used for the coupling system, then the coupling can be submerged in oil for lubrication, but the system requires maintenance and oil changes, and there is a risk of oil leakage to the main gearbox reservoir causing overheating
Solution Approach 1:
The patent merges the coupling lubrication system with the main gearbox oil reservoir by removing the separate oil compartment. The coupling components (flexible coupling half, stationary coupling half, and sliding fork) are directly lubricated by the main gearbox oil, eliminating the need for a separate sealed oil system while maintaining adequate lubrication for the coupling mechanism.
2Ease of operation
If the coupling system has a separate oil compartment, then lubrication is provided, but maintenance and oil changes are required increasing operational complexity
Solution Approach 1:
The patent combines the coupling lubrication with the main gearbox oil system, eliminating separate maintenance requirements. The coupling components are lubricated by the main gearbox oil that is already present in the system, so no separate oil changes or maintenance of a separate compartment is needed.
3Reliability
If the coupling system uses a separate oil compartment, then lubrication is ensured, but oil leakage risk increases which can cause overheating
Solution Approach 1:
The patent eliminates the separate oil compartment that could leak by integrating the coupling lubrication into the main gearbox oil system. Since there is no separate compartment with its own seals and connections, the risk of leakage from the coupling system is removed, and the oil is already part of the main monitored and managed lubrication system.
4Ease of repair
If traction motors are decoupled from the quill, then maintenance and replacement can be performed, but the coupling mechanism adds structural complexity
Solution Approach 1:
The patent segments the traction motor assembly from the quill by introducing a coupling mechanism with a sliding fork that can move between engaged and disengaged positions. This allows the traction motors to be mechanically separated from the drive train for maintenance while maintaining a relatively simple coupling structure that uses basic mechanical components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and maintenance-friendly operation by allowing independent operation with one motor in case of failure, reducing downtime and eliminating the need for separate lubrication systems, while maintaining gearbox integrity and preventing oil leakage.
Implementation Method 1
a pinion shaft assembly positioned in the gearbox for engagement with the motor shaft to transfer torque to the quill, wherein torque is transferred from the traction motor to the quill through the pinion shaft assembly when the pinion shaft assembly is engaged with the motor shaft, and wherein torque is not transferred from the traction motor to the quill through the pinion shaft assembly when the pinion shaft assembly is disengaged with the motor shaft
Data Source
AI summary
A top drive for well operations having a gearbox, a traction motor connected to the gearbox so that a motor shaft of the traction motor extends into the gearbox, a quill extending into the gearbox, a gear train positioned within the gearbox and mechanically connected between the traction motor shaft and the quill, and a connector positioned in the gear train, wherein in a coupled configuration the connector communicates torque through the gear train, and wherein in a decoupled configuration the connector does not communicate torque through the gear train. A method for operating a top drive by applying a first torque to a quill with two traction motors, disconnecting one of the traction motors from the quill, and applying a second torque less than 50% of the first torque to the quill with the non-disconnected traction motor.