Eccentric Bore Planetary Carrier for Backlash Elimination
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Solution Overview
Problem
Planetary gears in swivel motors of active roll stabilizers experience backlash and noise due to play in tooth meshing, particularly when the direction of rotation changes.
Innovation Solution
The planetary gear design features eccentric bores for planet bolts, which provide radial and tangential mobility, supported by elastic rings and damping elements like O-rings or metallic radial corrugated springs, ensuring a deadlock in meshing and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planetary gears with symmetrical bolt circles are used, then manufacturing is simple and assembly is easy, but backlash and noise occur due to play in tooth meshing when direction of rotation changes
Solution Approach 1:
The patent applies asymmetry by designing at least one bore in the planet carrier eccentrically, offset from the regular symmetrical bolt circle pattern. This creates an intentional asymmetrical arrangement where the planet bolt and planet are positioned at a different radial distance, generating a deadlock force that eliminates backlash in the tooth meshing between planet and ring gear, particularly during direction changes.
Solution Approach 2:
The eccentric bore design serves multiple functions simultaneously: it positions the planet bolt to create deadlock force for backlash elimination, provides radial and tangential mobility through enlarged diameter or elongated shape, and maintains structural support through elastic and damping elements. This multi-functional approach resolves the contradiction by achieving reliability improvement without proportionally increasing device complexity.
2Reliability
If rigid planet bolt support is used, then structural stability is maintained, but backlash occurs due to lack of mobility in tooth meshing
Solution Approach 1:
The patent transforms the static rigid support into a dynamic system by providing radial and tangential mobility to the planet bolt through the eccentric bore design. The enlarged diameter or elongated hole allows the planet bolt to move dynamically within the bore, enabling the tooth meshing to maintain contact and eliminate backlash while adapting to operational loads and direction changes.
Solution Approach 2:
The patent changes the physical parameters of the bore (enlarged diameter or elongated shape) to enable mobility, and introduces elastic and damping elements that alter the mechanical properties of the support system. These parameter changes allow the planet bolt to have both mobility for backlash elimination and controlled stability through the elastic-damping characteristics.
3Object-affected harmful factors
If elastic and damping movements are allowed, then noise is reduced and operational stability is enhanced, but additional components are required
Solution Approach 1:
The patent introduces elastic and damping elements as intermediary components between the planet bolt and the planet carrier structure. These intermediary elements absorb vibrations and dampen impacts, significantly reducing noise from tooth meshing while maintaining the structural connection. The eccentric bore design integrates these elements efficiently, achieving noise reduction with minimal additional complexity.
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 design eliminates or reduces backlash and noise by allowing for elastic and damping movements, maintaining gear alignment and preload, enhancing operational stability and quietness.
Implementation Method 1
The planetary bolt is supported in relation to the eccentric bore via elastically deformable rings
Implementation Method 2
damping elements like O-rings or metallic radial corrugated springs, ensuring a deadlock in meshing and reducing noise
Data Source
Figure 1~4
AI summary
The invention relates to a planetary transmission, comprising a planetary carrier (1), at least three planetary gears which are mounted on planet journals, an internal gear and a sun gear, wherein the planetary carrier (1) has bores (2, 3, 4) which are arranged on a common pitch circle (k) with regular centre points (O) which are distributed uniformly over the circumference for receiving the planet journals. It is proposed that at least one bore is configured as an eccentric bore (5), the eccentric centre point (M) of which is arranged offset in the radial and/or tangential direction with respect to the regular centre point (O).