Five-Blade Vane Variable Valve Timing Rotational Balance
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Solution Overview
Problem
Hydraulically-operated vane-type variable valve timing control systems with a five-blade vane member face challenges in maintaining rotational balance, leading to decreased control accuracy and increased rotational unbalance, which affects the phase change and torque application.
Innovation Solution
A five-blade vane member design with specific circumferential width distributions and a lock piston mechanism, where the first pair of blades has a reduced width compared to the second pair, and the first blade has a larger axial bore to accommodate the lock piston, ensuring balanced centrifugal forces and improved phase change capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the number of vane blades is increased to five to increase pressure-receiving area, then the phase change capability is improved, but the rotational balance of the vane member deteriorates
Solution Approach 1:
The vane member employs five blades with asymmetric circumferential width distribution. The first blade has a larger circumferential width than the second, third, fourth, and fifth blades. This asymmetric design creates a counterbalancing effect that compensates for the rotational unbalance inherent in five-blade configurations, thereby maintaining rotational balance while preserving the increased pressure-receiving area benefit
2Ease of manufacture
If the circumferential widths of all five blades are made equal, then the manufacturing is simplified, but the rotational accuracy and control precision deteriorate
Solution Approach 1:
The vane member implements local quality variation through different circumferential widths for different blades. Specifically, the first blade has a larger circumferential width while the other blades have smaller widths. This localized differentiation optimizes the center of gravity distribution and rotational characteristics, thereby improving rotational accuracy and control precision without significantly complicating the overall manufacturing process
3Adaptability or versatility
If the vane member is designed with five equidistant blades, then the phase change range is increased, but the control accuracy of the VTC device deteriorates
Solution Approach 1:
The invention breaks the symmetric equidistant arrangement by making the first blade have a larger circumferential width than the other blades. This asymmetric modification adjusts the center of gravity and mass distribution of the vane member, compensating for rotational unbalance and improving control accuracy while maintaining the five-blade configuration that provides the desired phase change range
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 design enhances rotational balance and control accuracy, allowing for precise phase changes and improved engine performance by maintaining balanced centrifugal forces and torque application across the vane member.
Implementation Method 1
a hydraulically-operated five-blade vane member equipped variable valve timing control (VTC) apparatus... capable of varying a relative phase of a camshaft to an engine crankshaft by supplying working fluid (hydraulic pressure) selectively to either one of a phase-advance hydraulic chamber and a phase-retard hydraulic chamber
Implementation Method 2
the lock pin is brought into engagement with the lock-pin hole, thus constraining rotary motion (free rotation) of the vane member relative to the cylindrical housing
Implementation Method 3
ensuring balanced centrifugal forces and improved phase change capabilities... maintaining balanced centrifugal forces and torque application across the vane member
Data Source
AI summary
A variable valve timing control apparatus employs a five-blade vane member fixedly connected to a camshaft end and rotatably disposed in a phase-converter housing formed integral with a sprocket driven by an engine crankshaft. Five phase-retard chambers and five phase-advance chambers are defined by five blades of the vane member and the housing, for creating a phase change of the vane member relative to the housing. A circumferential width of each of a first pair of blades, located on both sides of a first blade having a maximum circumferential width, is dimensioned to be less than a circumferential width of each of a second pair of blades, circumferentially spaced apart from the first blade rather than the first pair. The circumferential width of each of the second pair of blades is dimensioned to be less than the maximum circumferential width of the first blade.