Dog Clutch Rake Angle Retention for Marine Propulsion
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Solution Overview
Problem
In marine propulsion systems, the dog clutch member can become disengaged from the associated bevel gear when the driven shaft rotates faster than the driving shaft, leading to a loss of meshing relation during rapid deceleration.
Innovation Solution
The design incorporates a dog clutch with clutch projections having leading and trailing faces at specific rake angles, which maintain engagement with the bevel gear even when the propeller shaft rotates faster than the driving shaft, utilizing a splined connection to ensure synchronous rotation and torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dog clutch member is allowed to move axially freely, then it can disengage from the bevel gear during rapid deceleration, but this causes loss of meshing relation and unreliable torque transmission
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the gear projections, specifically the rake angle. By optimizing the rake angle of the leading and trailing faces of the gear projections, the system maintains reliable engagement under varying rotational speed conditions without requiring additional retention mechanisms.
Solution Approach 2:
The patent creates equipotentiality by designing the gear projections with specific rake angles that balance the forces acting on the clutch member during both acceleration and deceleration. This geometric configuration ensures that the clutch maintains meshing relation under different operational conditions without requiring active control or additional constraints.
2Reliability
If the gear projections have zero rake angle, then the manufacturing is simpler, but the clutch cannot maintain engagement when the propeller shaft rotates faster than the driving shaft
Solution Approach 1:
The patent applies parameter changes by specifying optimal rake angles for the gear projections. This geometric parameter modification enables the clutch to maintain engagement during rapid deceleration while keeping the manufacturing process relatively simple, as the rake angle can be incorporated into standard gear cutting operations.
3Reliability
If the leading and trailing faces of gear projections are perpendicular to the axis, then the structure is simpler, but axial movement of the clutch member cannot be prevented during rapid deceleration
Solution Approach 1:
The patent applies parameter changes by introducing rake angles to the leading and trailing faces of the gear projections. This geometric modification prevents axial movement of the clutch member during rapid deceleration by creating mechanical interference, while the overall simple geometric form is maintained.
Data Source
AI summary
In a marine transmission, trailing faces of each of a plurality of gear projections extending axially from a forward gear are provided with a rake angle. This rake angle of each trailing face cooperates with an associated surface of each of a plurality of clutch projections to retain a dog clutch in an axial position relative to the forward gear even during periods when a marine vessel is rapidly decelerating and, as a result, the dog clutch moves into driving relation with the forward gear.