Starter Drive Protective Sleeve for Impurity Protection
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Solution Overview
Problem
Existing thermal engine starters face issues with protecting the sliding interface between the pinion and sleeve from impurities and pollution, which can hinder the sliding motion and spring compression, especially during high-speed rotation and 'stop and go' functions, leading to wear and potential damage.
Innovation Solution
A protective sleeve is mounted around the elastic element forming a chamber between the pinion and the sleeve, which slides on the outer periphery, preventing impurities from entering and is rigid to withstand centrifugal forces, ensuring the sleeve and spring remain protected and functional.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a flexible joint such as a bellows is used to protect the sliding zone, then protection against impurities is improved, but the bellows deforms due to the dashpot effect and wears rapidly
Solution Approach 1:
The patent uses a flexible membrane (diaphragm) instead of a bellows to protect the sliding zone. The membrane is held taut by a tensioning element, preventing the deformation and wear issues that plague bellows during rapid pinion movements. This resolves the contradiction by providing effective impurity protection while maintaining structural integrity under dynamic conditions.
2Reliability
If a coil spring is used during high rotation speeds, then engagement capability is improved, but centrifugation of the spring damages the bellows
Solution Approach 1:
The flexible membrane is specifically designed to withstand centrifugal forces during high-speed rotation, unlike bellows which deform and fail. The membrane's construction and tensioning system allow it to maintain its protective function even when the pinion rotates at high speeds, resolving the contradiction between engagement capability and protection integrity.
3Strength
If the protective sleeve is rigid, then resistance to centrifugal forces is improved, but wear due to friction increases
Solution Approach 1:
The protection system is segmented into two distinct functional components: a rigid protective sleeve that withstands centrifugal forces, and a separate flexible membrane that provides impurity protection and reduces friction. This segmentation allows each component to be optimized for its specific function, resolving the contradiction between structural strength and wear resistance.
Solution Approach 2:
The flexible membrane acts as an intermediary between the rigid protective sleeve and the external environment. It provides a low-friction surface for the pinion while the rigid sleeve handles centrifugal loads, thus resolving the contradiction by allowing the rigid structure to exist without directly contacting the moving pinion.
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 effectively prevents impurities from entering the chamber, reduces wear, and maintains the integrity of the starter motor components during operation, ensuring reliable engagement and disengagement of the pinion with the ring gear.
Implementation Method 1
an elastic element mounted on the first portion and disposed between the pinion and the second portion of the sleeve configured to constrain the pinion in the initial position
Implementation Method 2
a protective sleeve mounted around the elastic element forming a chamber between the pinion and the second portion of the sleeve
Implementation Method 3
the protective sleeve is rigid. This prevents the sleeve from being deformed by centrifugation
Data Source
Figure 1~2
Figure 3
Figure 4a~5
AI summary
The present invention relates to a starter (20) for a thermal engine, the starter (20) comprising: - a sleeve (11) mounted for translational movement on a drive shaft (5), the sleeve comprising a first portion (11a) and a second portion (11b) of a diameter greater than the first portion (11a), - a stop element (17) mounted on the first portion (11a) of the sleeve, the stop element (17) being fixed in translation with the sleeve (11), - a pinion (15) mounted on the first portion (11a) of the sleeve (11) between the stop element (17) and the second portion (11b), the pinion (15) being translationally movable relative to the sleeve (11) between an initial position abutting the stop element (17) and an offset position in which the pinion (15) is distant from the stop element (17).- an elastic element (19) mounted on the first portion (11a) and disposed between the pinion (15) and the second portion (11b) of the sleeve (11) configured to constrain the pinion (15) in the initial position, the launcher (20) also comprising: - a protective sleeve (23) mounted around the elastic element (19) forming a chamber between the pinion (15) and the second portion (11b) of the sleeve (11) and in which the protective sleeve (23) is able to slide on the outer periphery of the pinion (15) or on the second portion (11b) of the sleeve (11) when the pinion (15) moves between the initial position and the offset position.