Marine Drive Shaft Braking and Locking in Tight Axial Space
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Solution Overview
Problem
Drive units of marine vessels face issues with propeller damage in strong currents, necessitating braking and blocking of the drive shaft without increasing axial dimension, especially in ice-breaking applications where additional axial constraints are present.
Innovation Solution
A braking and locking system for the drive shaft, featuring multiple systems positioned between the upstream roller bearing and propulsion element, utilizing an actuator with a worm screw and gear motor to control friction on a brake pad lining, which provides radial support and is immersed in seawater to prevent dust and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If braking and locking systems are added to prevent propeller damage in strong currents, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the braking function and locking function into a single integrated system. The brake pads can apply friction to the drive shaft for braking, and when activated, they lock the drive shaft in position. This merging of functions reduces the number of separate components needed while providing both protection modes.
Solution Approach 2:
The braking system is designed to serve multiple purposes: it can brake the drive shaft during operation to prevent propeller damage in strong currents, and it can lock the drive shaft when the propeller is removed or during maintenance. This multi-functionality improves reliability without proportionally increasing complexity.
2Reliability
If multiple braking and locking systems are positioned around the drive shaft, then reliability is improved through radial support, but device complexity increases
Solution Approach 1:
The patent positions braking and locking systems at specific locations around the drive shaft (typically two systems positioned 180 degrees apart). This local placement provides adequate radial support and braking capability without the need for complete 360-degree coverage, optimizing the balance between reliability and complexity.
3Object-affected harmful factors
If the braking system is placed in the drive unit housing, then protection against dust and heat generation is improved, but axial dimension is increased
Solution Approach 1:
The braking and locking systems are nested within the existing drive unit housing structure. The brake pads and actuator mechanisms are positioned in the annular space between the drive shaft and the housing, utilizing available space rather than adding external components. This nesting approach protects the braking components from dust and heat while minimizing axial dimension increase.
Solution Approach 2:
Instead of extending the braking system axially, the patent positions the braking components in the radial direction within the existing housing. The brake pads contact the drive shaft radially, and the actuator mechanisms are arranged in the annular space, transforming the spatial arrangement from axial extension to radial utilization, thereby protecting components without significantly increasing axial dimension.
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
Effectively brakes and locks the drive shaft, preventing damage from strong currents and allowing safe return to port, while maintaining a compact axial dimension suitable for ice-breaking applications without generating dust or heat during operation.
Implementation Method 1
the actuator controls friction of the brake pad lining on the brake disc
Implementation Method 2
the brake pad is driven away radially from the brake disc by a spacing component, such as a spring
Implementation Method 3
the actuator includes a worm screw turned by a gear motor and provides a translation linear motion to an actuator arm
Data Source
Figure 1
Figure 2
AI summary
The drive unit (12) is designed to be mounted on a marine vessel (2), including a mobile housing, (16) and is able to pivot around an axis (A) against the hull (4) of the marine vessel. A drive shaft (20) mounted rotary is against the mobile housing (16) and is supported by two roller bearings (24, 26). A propulsion element (36) rotates in solidarity with the drive shaft. The propulsion unit has, at the front, at least two braking and locking systems (40) of the drive shaft (20) located in an area between the upstream rolling bearing and propulsion element (36).