Propulsion Steering Differential Torque Management
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Solution Overview
Problem
Existing propulsion units with steering arrangements face issues with torque overload due to external forces like ice or bottom contact, which can cause the force transmission to brake, leading to inefficiencies and potential damage.
Innovation Solution
Incorporating a differential in the force transmission arrangement between the steering electric motor and the propulsion unit, which locks the third shaft below a threshold torque and allows it to rotate above this threshold, distributing power to a brake device to manage excessive torque, thereby reducing the torque on the force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a steering electric motor with high gear ratio is used to rotate the propulsion unit, then the steering torque is amplified, but the inertia of the motor is multiplied by the square of the gear ratio, causing excessive counter torque that may brake the force transmission
Solution Approach 1:
The force transmission arrangement is segmented into multiple independent transmission paths: a first transmission path from the steering electric motor through the differential to the propulsion unit, and a second transmission path from the steering electric motor through the brake device to the propulsion unit. This segmentation allows the system to distribute torque and prevent overload in any single path, resolving the contradiction between torque amplification and transmission reliability.
Solution Approach 2:
The differential acts as an intermediary mechanism between the steering electric motor and the propulsion unit. It provides a low-inertia route for torque transmission and includes a brake device that can absorb excessive counter torque generated by the motor's inertia, preventing the force transmission from braking while still allowing effective steering torque application.
2Device complexity
If the force transmission arrangement directly connects the steering electric motor to the propulsion unit, then the structure is simple, but external loads from ice or bottom contact can produce torque that brakes the force transmission
Solution Approach 1:
The force transmission arrangement incorporates a dynamic brake device that can adaptively engage or disengage based on operating conditions. The brake device is configured to prevent rotation of the second shaft when the propulsion unit is in normal operation, but can release to allow rotation when external loads are detected, providing dynamic protection against transmission braking while maintaining structural simplicity.
3Productivity
If the third shaft of the differential is locked to distribute power only between the motor and propulsion unit, then the transmission is efficient, but the system cannot handle external torque from ice or bottom contact
Solution Approach 1:
The brake device connected to the third shaft provides dynamic adaptability by being able to engage or disengage based on external load conditions. When locked, the system maintains high power transmission efficiency with a direct path from motor to propulsion unit. When external torque from ice or bottom contact is detected, the brake device can release to allow the third shaft to rotate, providing a relief path for excessive torque and preventing transmission damage.
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
This solution effectively limits maximum torque during overload situations, preventing brake failure and ensuring smooth operation by providing a secondary low-inertia route for excessive torque, thus protecting the force transmission and propulsion unit.
Implementation Method 1
the force transmission arrangement comprises a differential comprising a first shaft rotationally connected to the steering electric motor, a second shaft rotationally connected to the propulsion unit, and a third shaft rotationally connected to a brake device
Implementation Method 2
the third shaft is allowed to start rotating when the torque produced by an external force on the propulsion unit exceeds the threshold value, whereby power is distributed from the steering electric motor to the rotation of the propulsion unit and to the brake device
Data Source
AI summary
The arrangement includes at least one steering electric motor rotating the propulsion unit via a force transmission arrangement. The force transmission arrangement includes a differential including a first shaft connected to the steering electric motor, a second shaft connected to the propulsion unit, and a third shaft connected to a brake device. The third shaft is locked from rotation when a torque produced by an external force on the propulsion unit is below a threshold value, whereby power is distributed only from the steering electric motor to the propulsion unit or vice a versa. The third shaft is allowed to start rotating when the torque produced by the external force on the propulsion unit exceeds the threshold value, whereby power is distributed from the steering electric motor to the rotation of the propulsion unit and to the brake device or from the rotation of the propulsion unit to the steering electric motor and to the brake device.