Valve Timing Rotor-Oldham Coupling Layout for Backlash Noise
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Solution Overview
Problem
Existing valve timing adjustment devices using Oldham couplings generate noise due to uncontrolled clearances between the Oldham coupling and other members, despite reducing meshing-related noise through urging members.
Innovation Solution
The device configures a relationship where θ2<θ1, with θ1 being the maximum tilt of the planetary rotor relative to the driven Oldham flange and θ2 the maximum tilt in the Oldham coupling clearance, allowing active reduction of clearances and noise by tilting the planetary rotor relative to the drive-side and driven-side rotors and Oldham coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the planetary rotor is tilted to reduce clearances in the Oldham coupling, then noise from clearances is reduced, but the complexity of controlling the tilt angle increases
Solution Approach 1:
The patent implements self-service by designing the planetary rotor to automatically tilt at a controlled angle through its own rotational motion and geometric configuration. The tilt angle is determined by the structural parameters of the planetary gear mechanism itself, eliminating the need for external control mechanisms and reducing system complexity while still achieving clearance reduction and noise suppression
Data Source
AI summary
A drive-side rotor is rotated synchronously with a crankshaft. A driven-side rotor is rotated integrally with a camshaft. An internal gear section is formed at the driven-side rotor. An Oldham coupling includes: a driven Oldham flange that is formed at the drive-side rotor; a drive Oldham flange that is formed at the planetary rotor; and an Oldham intermediate that is configured to synchronize rotation of the driven Oldham flange and rotation of the drive Oldham flange while permitting eccentricity between the driven Oldham flange and the drive Oldham flange. There is satisfied a relationship of θ2<θ1 where: θ1 is a maximum tilt amount of the planetary rotor relative to the driven Oldham flange; and θ2 is a maximum tilt amount of the planetary rotor in a clearance formed at the Oldham coupling.