Small Engine Starter Drive Cam Support via Segmented Plates
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Solution Overview
Problem
The existing starter mechanisms for small-sized engines face issues with ensuring accurate concentricity and stability of the drive cam, drive gear, rope reel, and force storage spiral spring, leading to abnormal noise and malfunction, especially under pressure angle conditions, due to the load-bearing limitations of the slender shaft supporting these components.
Innovation Solution
A starter mechanism where the rope reel and drive cam are directly connected via a one-way clutch mechanism, with support plates protruding from the starter casing to rotatably support the drive cam's end portions in bearing holes, allowing stable support and smooth rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the drive cam, drive gear, rope reel and force storage spiral spring are supported onto a slender shaft, then the structure is compact and simple, but the shaft cannot bear the load of these parts so that the support is apt to vary unstably causing contact and abnormal noise
Solution Approach 1:
The invention divides the support function into two independent parts: the slender shaft maintains rotational motion while the support plates (formed integrally with the starter casing) bear the radial loads. This segmentation allows each component to perform its specialized function without overload.
Solution Approach 2:
The support plates act as intermediary elements between the starter casing and the drive cam assembly. These plates transfer radial loads from the drive cam to the starter casing, relieving the slender shaft of load-bearing responsibilities while maintaining rotational connectivity.
2Use of energy by moving object
If the rope reel and drive cam are connected through a force storage spiral spring, then the force can be stored, but the drive cam rotates at low speed and the engine cannot start reliably
Solution Approach 1:
The invention extracts the force storage function from the transmission path between the rope reel and drive cam. By removing the force storage spiral spring from this specific path, the rope reel can directly drive the drive cam at high speed, while force storage is handled separately by the recoil starter mechanism.
Solution Approach 2:
The recoil starter mechanism performs preliminary force storage by winding the spiral spring when the rope is pulled. This preliminary action stores energy independently, allowing the drive cam to rotate at high speed without being constrained by force storage requirements in the transmission path.
3Reliability
If the drive cam is supported by the starter casing through support plates, then the drive cam is stably supported, but the structure becomes more complex
Solution Approach 1:
The support plates are formed integrally with the starter casing as a single piece, merging the support function into the existing structure. This eliminates the need for separate support components while providing stable support for the drive cam.
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 configuration ensures high rotational speed of the drive cam when the rope reel is pulled, facilitating reliable engine start and stable support of the drive cam, reducing the likelihood of noise and malfunction.
Implementation Method 1
the rope reel and the drive cam are directly operably connected to each other by a one-way clutch mechanism
Implementation Method 2
opposite end portions of the drive cam are rotatably supportedly fitted into bearing holes formed in the support plates respectively
Data Source
AI summary
A starter for a small-sized engine, capable of reliably starting the engine by a rope reel and stably supporting a drive cam. The starter has, received in a starter case, a cylindrical drive cam having a starter clutch mechanism, the rope reel for a recoil starter, and a starter motor, where the drive cam can be selectively operably connected to the rope reel or a starter motor. The rope reel is directly operably connected to the drive cam through a one-way clutch mechanism. Support plates are formed projected from the inner surface of the starter case toward the outer peripheral surface of the drive cam. Opposite ends of the drive cam are rotatably supportedly fitted into bearing holes formed in the support plates.