Outboard Motor Steering Rack Detection Without Coaxial Sensors
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Solution Overview
Problem
Conventional outboard motors face challenges in detecting the rotational position of the outboard motor body about the steering shaft without providing a detector coaxially with the steering shaft, due to the drive shaft penetrating through the rotary member and interfering with detection mechanisms.
Innovation Solution
The outboard motor incorporates a rack position detector on the opposite side of the pinion, which detects the position of a rack that linearly moves to rotate the pinion, allowing for the detection of the rotational position of the outboard motor body without being coaxial with the steering shaft, and includes a rack position detection gear with a smaller outer diameter to minimize the steering mechanism's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detector is provided coaxially with the steering shaft to detect the rotational position of the outboard motor body, then the detection accuracy is improved, but the drive shaft cannot penetrate through the rotary member due to interference
Solution Approach 1:
The detector is relocated from a coaxial position with the steering shaft to a position on the opposite side of the rack from the pinion. This spatial relocation in a different dimension allows the detector to function without interfering with the drive shaft's path through the pinion's through-hole, resolving the conflict between detection capability and drive shaft penetration.
2Object-generated harmful factors
If the rack position detector is placed on the opposite side of the rack from the pinion, then interference with the driving mechanism is prevented, but the detection distance increases
Solution Approach 1:
The rack serves as an intermediary element that transmits the rotational motion of the pinion to the detector. The detector measures the linear position of the rack, which indirectly reflects the rotational position of the pinion and steering shaft, enabling detection without direct coaxial contact and thus avoiding interference with the drive mechanism.
3Measurement precision
If a rack position detector is added to detect the rack position, then the rotational position detection is enabled, but the size of the steering mechanism increases
Solution Approach 1:
The rack position detector uses a gear with a smaller outer diameter than the pinion. By changing the parameter of gear size, the detector achieves the necessary detection function while occupying less space, thereby minimizing the increase in overall steering mechanism size.
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
The solution enables accurate detection of the rotational position of the outboard motor body without increasing the size of the steering mechanism, ensuring efficient steering control and preventing interference with driving mechanisms.
Implementation Method 1
a rack operable to linearly move to rotate the pinion, and a rack position detector on a first side of the rack opposite to the pinion to detect a position of the rack
Data Source
AI summary
An outboard motor includes a steering mechanism including a pinion located in a central portion of an outboard motor body in a right-left direction and operable to rotate together with the outboard motor body, a rack operable to linearly move to rotate the pinion, and a rack position detector on a first side of the rack opposite to the pinion to detect a position of the rack.