Nested Electric and Hydraulic Camshaft Adjusters
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Solution Overview
Problem
Existing camshaft adjusting systems for concentrically arranged camshafts are limited by the dependency of angular adjustments between the inner and outer shafts, requiring extensive hydraulic adjustments that are time-consuming and prone to control inaccuracies.
Innovation Solution
A camshaft adjusting system where the electric camshaft adjuster's output ring is radially and axially integrated into the hydraulic camshaft adjuster's rotor, decoupling the adjusting ranges and allowing independent adjustment of both shafts, with a flat design and high-speed capabilities, using a harmonic drive mechanism and chain drive for concentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If hydraulic adjusters are used for both camshafts in a concentric arrangement, then the system can be compact, but the adjusting ranges become coupled and control accuracy deteriorates
Solution Approach 1:
The patent divides the camshaft adjusting system into two independent adjusting mechanisms: a hydraulic adjuster for the outer camshaft and an electric adjuster for the inner camshaft. This segmentation allows each adjuster to operate independently with its own adjusting range, eliminating the coupling problem while maintaining compact concentric arrangement through the nested configuration of the electric adjuster within the hydraulic adjuster.
Solution Approach 2:
The electric camshaft adjuster is nested within the hydraulic camshaft adjuster, with the output ring of the electric adjuster arranged radially inside the rotor of the hydraulic adjuster. This nesting approach achieves compact installation space while maintaining independent adjusting ranges for both camshafts, as each adjuster operates in its own spatial zone without interfering with the other's adjusting range.
2Adaptability or versatility
If the inner shaft adjusting range is increased to counteract the outer shaft, then the adjusting capability improves, but the adjustment process becomes time-consuming
Solution Approach 1:
By segmenting the adjusting functions into two independent systems with distinct adjusting ranges, the patent eliminates the need for the inner shaft to perform excessive counter-adjustments. The outer shaft's hydraulic adjuster handles its own adjusting range independently, while the inner shaft's electric adjuster handles its own range, allowing both to reach target positions simultaneously without time-consuming back-and-forth adjustments.
Solution Approach 2:
The patent replaces the purely hydraulic adjusting mechanism with a hybrid system where the inner camshaft uses an electric adjuster. This substitution enables more precise and faster control of the inner camshaft's adjusting range, reducing the time required for adjustments while maintaining the ability to achieve the necessary adjusting capability.
3Device complexity
If hydraulic adjusters are used for both camshafts, then the system structure is simplified, but the control accuracy and speed deteriorate
Solution Approach 1:
The patent segments the adjusting system into two parts with different actuation mechanisms: hydraulic for the outer camshaft and electric for the inner camshaft. This segmentation allows optimization of each subsystem for its specific requirements, with the electric adjuster providing higher control accuracy and speed for the inner camshaft while the hydraulic adjuster handles the outer camshaft, overall maintaining reasonable system complexity through the modular nested design.
Data Source
AI summary
A camshaft adjusting system (1) is provided for a first camshaft (2) and a second camshaft (3) which are arranged concentrically with respect to one another, the second camshaft being arranged inside the first camshaft. A hydraulic camshaft adjuster (4) of the vane-cell type is set up for the adjustment of the first camshaft, and an electric camshaft adjuster (5) is set up for the adjustment of the second camshaft. A rotor contact flange (17) of an output ring (6) of the electric camshaft adjuster is arranged radially inside a first cover (23) of the hydraulic adjuster, the output ring which is equipped for the transmission of torque to the second camshaft is arranged at least partially radially and axially inside a rotor (7) of the hydraulic camshaft adjuster. A camshaft adjusting unit is also provided having a camshaft adjusting system of this type and two camshafts.