Variable Displacement Oil Pump Vane Spacing for Noise Reduction
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Solution Overview
Problem
Conventional vane oil pumps generate pressure ripples that cause tonal noise and vibration in powertrain components, leading to noise, vibration, and harshness (NVH) issues in vehicles.
Innovation Solution
A vane fluid pump design featuring a cam ring and inner rotor with non-uniformly sized segmented pumping chambers, where sector angles are strategically varied to disrupt harmonics and reduce pressure ripples, incorporating a series of vanes positioned within slots on the rotor to minimize objectionable harmonics such as 3n, 4n, and 5n orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional vane pumps with uniform vane spacing are used, then the pump structure is simple and easy to manufacture, but pressure ripples and tonal noise are generated
Solution Approach 1:
The patent applies asymmetry by configuring non-uniform vane spacing in the inner rotor, where adjacent vanes have different angular spacings. This asymmetric arrangement disrupts the periodic pressure ripples generated by conventional uniform spacing, thereby reducing tonal noise and harmonics while maintaining the basic pump structure
Solution Approach 2:
The patent implements local quality by varying the angular spacing of specific vanes relative to each other while maintaining overall rotational symmetry. Each vane position is locally optimized to disrupt specific harmonic frequencies, creating non-uniform local characteristics that reduce noise without requiring complete structural redesign
2Object-affected harmful factors
If non-uniform vane spacing is implemented to reduce noise, then pressure ripple and tonal noise are reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the angular position parameters of the vanes relative to each other, creating a non-uniform distribution pattern. This parameter variation disrupts the harmonic generation mechanism while maintaining compatibility with conventional manufacturing processes, as the vanes can still be produced using standard techniques with updated positioning specifications
Data Source
AI summary
A vane fluid pump for a vehicle component has an inner rotor supported within a cam ring. A series of vanes is positioned within a series of slots in an inner rotor to define and separate a series of non-uniformly sized segmented pumping chambers to disrupt harmonics during operation to reduce pressure ripples and associated tonal noise. One chamber has a first sector angle being within a first predetermined range of a nominal value. A portion of the chambers each has a sector angle greater than the first sector angle, with an average sector angle greater than the nominal value by a second predetermined range. A remaining portion of the chambers each has a sector angle less than the first sector angle, with an average sector angle less than the nominal value by the second predetermined range.