Starter Backlash Absorption Mechanism for Helical Gear Noise Reduction
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Solution Overview
Problem
In starters with helical pinion and ring gears, rotational speed differences cause axial displacement, leading to backlash and noise generation, particularly in vehicles with idle stop functions where engine starting is frequent, resulting in irregular rotation and gear noise.
Innovation Solution
A starter with a backlash absorption mechanism that maintains constant elastic contact between the gear plunger and clutch outer part, and a pinion spring to absorb shock, preventing axial displacement and noise by optimizing the elastic moduli of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If helical pinion and ring gears are used to improve meshing property, then meshing property is improved, but axial displacement and noise occur due to rotational speed differences
Solution Approach 1:
A backlash absorption mechanism is introduced as an intermediary component between the pinion gear and the drive shaft. This mechanism includes a plunger and spring assembly that absorbs axial displacement caused by rotational speed differences between the pinion and ring gears, preventing the displacement from transmitting to the gear mesh and thus eliminating noise while preserving the benefits of helical gear engagement
2Reliability
If dimensional errors are added to design to prevent aperture generation, then reliability is improved, but device complexity increases
Solution Approach 1:
Rather than complicating the design of individual components to account for dimensional errors, a backlash absorption mechanism is introduced as an intermediary that compensates for these errors. The mechanism includes a plunger, spring, and housing assembly that actively absorbs dimensional variations and maintains reliable engagement without requiring complex dimensional specifications for each component
3Force
If the lever is set to maximum attraction position to improve engagement, then engagement force is improved, but the lever may not be properly attracted due to dimensional errors
Solution Approach 1:
The backlash absorption mechanism provides beforehand cushioning by pre-absorbing axial displacement and dimensional errors before they can affect the engagement process. The spring-loaded plunger assembly is positioned to compensate for potential dimensional variations, ensuring that the lever can be reliably attracted to the maximum position without being hindered by cumulative dimensional errors in the transmission path
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 aperture generation between the electromagnetic device and clutch mechanism, reduces noise, and enhances starter durability by absorbing shock and optimizing elastic moduli, ensuring smooth and silent engine starting.
Implementation Method 1
a backlash absorption mechanism in which a plunger spring configured to absorb shock in the axial direction is installed
Implementation Method 2
a pinion spring disposed between the pinion inner part and the pinion gear and configured to absorb shock when the pinion gear and the ring gear are helically engaged
Implementation Method 3
a magnet switch (an electromagnetic device) in the axial direction is spline-engaged with the drive shaft
Data Source
AI summary
A starter (1) includes a motor unit (3), an output shaft (4) configured to receive a rotational force of the motor unit (3) and rotate, a pinion gear (74) (a pinion mechanism) helically engageable with a ring gear (23) of an engine, a clutch mechanism (5) configured to transmit the rotational force of the output shaft (4) to the pinion gear (74), and an electromagnetic device (9) configured to bias a pressing force toward the ring gear (23) to the clutch mechanism (5) and the pinion gear (74), wherein a plunger spring (91) (a backlash absorption mechanism) configured to bring one end (81a) (a point of action) of a plunger inner part (81) in constant elastic contact with the clutch mechanism (5) is installed at the electromagnetic device (9).