Starter Pinion Shielding Member for Water Intrusion Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing starters are prone to performance degradation and defective operation due to the intrusion of foreign materials like grit and dust or water droplets into the housing through the opening portion, leading to rusting and defective sliding engagements in the speed reduction gear unit and clutch.
Innovation Solution
A starter design featuring a pinion shielding member with an outer diameter greater than the pinion gear's addendum circle, forming a hollow cylindrical configuration with one end open towards the ring gear and the other closed, which acts as a waterproof barrier to prevent foreign materials and water droplets from entering the housing, and optionally includes ribs to further minimize water intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the opening portion of the nose portion is left open for normal operation, then the starter can function properly with the pinion gear engaging the ring gear, but foreign materials such as grit and dust or water droplets can intrude inside the housing through the opening portion
Solution Approach 1:
The pinion shielding member is configured as a cylindrical shell structure with an open end facing the ring gear and a closed end facing away from it. This shell structure allows the pinion gear to engage the ring gear through the open end while the curved surface of the cylinder shields the housing opening from foreign materials, preventing grit, dust, and water droplets from intruding inside the housing during normal operation.
2Object-affected harmful factors
If a shielding structure is added to prevent foreign material intrusion, then foreign materials can be blocked from entering the housing, but the device complexity and number of components increase
Solution Approach 1:
The pinion shielding member is integrated with the pinion moving body, which already includes the pinion gear and helical spline engagement structure. By combining the shielding function with the existing moving body components, the patent avoids adding a completely separate shielding device, thereby reducing overall device complexity while still achieving effective protection against foreign materials.
3Object-affected harmful factors
If the pinion shielding member has a large outer diameter to provide better shielding, then foreign material protection is improved, but the clearance between the nose portion and pinion shielding member varies during operation
Solution Approach 1:
The pinion shielding member is designed with a specific outer diameter that is optimized to provide adequate shielding while maintaining consistent clearance. The cylindrical configuration with carefully selected dimensions ensures that the shielding effectiveness is sufficient without causing variable clearance issues during the pinion's movement between engaged and disengaged positions.
Data Source
AI summary
A starter is disclosed as having a housing carrying thereon a motor, and a pinion moving body including a pinion gear, operative to mesh with a ring gear of an engine to transfer a rotational force of the motor thereto, and a pinion shielding member connected to the pinion gear at a front end thereof. The pinion shielding member has an outer circular periphery, having an outer diameter greater than the diameter of the addendum circle of the pinion gear, and a bottomed cylindrical configuration formed with a hollow portion having a front opened end and a closed rear end. Further, a clearance between an inner circumferential periphery of the nose portion and the outer circular periphery of the pinion shielding member is minimized to avoid interference between the nose portion of the housing and the pinion shielding member.