Starter Drive Pinion Venting for Retaining Force Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing starter drive assemblies for motor vehicle combustion engines face issues with retaining forces generated by variable-volume chambers, which can slow the movement of the drive pinion due to suction and compression effects, and require complex tools and mechanical weakening of the pinion body to address these issues.
Innovation Solution
A starter drive assembly with a through-opening in the annular wall of the drive shaft or pinion body vents the variable-volume chamber to the external atmosphere, preventing the generation of retaining forces and maintaining mechanical rigidity, and is easy to implement with a simple hole creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If superficial grooves are created on the pinion body to vent the chamber, then air communication is achieved, but the pinion body is mechanically weakened and complex tooling is required
Solution Approach 1:
The invention extracts the harmful air trapping function from the pinion body by creating a through-opening that vents the chamber to the external atmosphere. This removes the source of retaining forces without requiring grooves that would weaken the pinion body structure.
Solution Approach 2:
The through-opening creates a porous pathway through the drive shaft or pinion body wall, allowing air to pass through freely. This porous structure eliminates the suction and compression effects that cause retaining forces, while maintaining the structural integrity of the component.
2Object-generated harmful factors
If superficial grooves are created on the pinion body to vent the chamber, then air communication is achieved, but complex tooling is required for cold heading
Solution Approach 1:
The invention simplifies the venting solution by extracting the air communication pathway from complex grooves to a simple through-opening. This can be achieved with basic drilling or punching tools during standard manufacturing, eliminating the need for specialized cold heading tooling.
3Ease of operation
If bearing bushings are fitted to reduce friction, then movement is facilitated, but air trapping is improved and retaining forces are amplified
Solution Approach 1:
The through-opening acts as an intermediary element that allows air to pass through the bearing bushing assembly. This mediator function prevents air trapping between the bushings and moving parts, eliminating the suction cup effect while maintaining the low-friction movement benefits of the bushings.
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 solution effectively avoids the generation of retaining forces that could slow the movement of the drive pinion, ensuring smoother transitions between positions and maintaining the mechanical integrity of the starter drive assembly.
Implementation Method 1
the chamber is vented via a through-opening made in an annular wall of the said drive shaft or of the said pinion body
Implementation Method 2
the increase in the volume of air contained in the chamber 9 as a result of the pinion body 3 moving further away with respect to the drive shaft 5 generates a suction effect
Implementation Method 3
as the starter drive assembly 1 moves from the active position into the rest position, the reduction in the volume of air contained in chamber 9 as a result of the pinion body 3 moving closer to the drive shaft 5, generates a resistive compression force
Data Source
AI summary
The invention relates mainly to a starter (11) for a motor vehicle combustion engine, comprising:an electric motor (15),a drive pinion (60),a pinion body (61) on which said drive pinion (60) is mounted,a drive shaft (12) able to transmit a torque derived from the electric motor (15) to the drive pinion (60) via the pinion body, the pinion body (61) being mounted with the ability to slide axially with respect to the drive shaft (12),and in which, with there being a chamber (86) delimited notably by one end of the drive shaft (12) and one end of the pinion body (61) opposite the end of the drive shaft (12), the chamber (86) is vented via a through-opening (85) made in an annular wall of the drive shaft (12) or of the pinion body (61).