Oil Pump Rotor Tooth Profile Correction for Discharge and Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional oil pumps face challenges in increasing discharge capacity while minimizing pulsation and noise, often requiring larger rotor sizes or increased weight, which contradicts the need for miniaturization to reduce engine friction and fuel costs.
Innovation Solution
The oil pump rotor design involves correcting the tooth profile of the inner and outer rotors using mathematical curves, specifically applying corrections in the circumferential and radial directions to maintain the distance between addendum and tooth groove circles, enhancing discharge rate without increasing rotor size and reducing pulsation and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of teeth is reduced to increase discharge amount per cell, then discharge capacity increases, but pulsation and noise increase
Solution Approach 1:
The patent modifies the tooth profile parameters by applying corrections in both the circumferential and radial directions to the mathematical curve. This changes the geometry of the teeth while maintaining the same number of teeth, thereby increasing discharge capacity without exacerbating pulsation and noise
2Object-generated harmful factors
If the number of teeth is increased to reduce pulsation and noise, then pulsation and noise decrease, but discharge capacity decreases
Solution Approach 1:
Instead of changing the number of teeth, the patent applies parameter corrections to the tooth profile geometry. The circumferential and radial corrections optimize the tooth shape to reduce pulsation and noise while maintaining adequate discharge capacity
3Productivity
If the outside radius or thickness of the rotor is increased to secure required discharge amount, then discharge capacity increases, but size and weight increase
Solution Approach 1:
The patent achieves increased discharge capacity through geometric parameter corrections of the tooth profile rather than increasing rotor dimensions. The corrections in the circumferential and radial directions optimize the volume utilization of existing rotor size, avoiding weight increase
4Productivity
If the outside radius or thickness of the rotor is increased to secure required discharge amount, then discharge capacity increases, but friction increases
Solution Approach 1:
By correcting the tooth profile parameters rather than increasing rotor size, the patent maintains a compact rotor with smaller contact surfaces, thereby reducing friction losses while achieving the required discharge capacity
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
An oil pump rotor includes an inner rotor formed with n (n:a natural number) external teeth, an outer rotor formed with n+1 internal teeth which are in meshing engagement with each of the external teeth, and a casing having an suction port for drawing in fluid and a discharge port for discharging fluid. And the oil pump conveys the fluid by drawing in and discharging the fluid due to changes in volumes of cells formed between surfaces of the internal teeth and surfaces of the external teeth during rotations of the rotors under meshing engagement therebetween. And the tooth profile of the external teeth of the inner rotor is formed by a deformation in the circumferential direction and a deformation in the radial direction applied to a profile defined by a mathematical curve with the deformation in the circumferential direction is applied while maintaining the distance between the radius (RA1) of an addendum circle (A1) and the radius (RA2) of the tooth groove circle (A2).