Oil Pump Eccentric Adjustment via Guide Pin Constraint
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Solution Overview
Problem
Existing oil pumps with eccentrically arranged inner and outer rotors face challenges in maintaining accurate engagement due to movable cam rings, leading to fluctuations in discharge amount and requiring complex, high-accuracy processing for tooth line formation, which results in size growth and operational limitations.
Innovation Solution
The introduction of a guide means, including guide pins and grooves, allows the adjustment ring to be actuated while maintaining contact with the casing, ensuring consistent engagement between the outer teeth of the inner rotor and the inner teeth of the outer rotor, enabling precise adjustment of the eccentric positional relationship without size increase, and allowing various movement forms for enhanced design freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a movable cam ring is used to adjust the eccentric position, then the discharge amount can be adjusted, but the engagement accuracy between rotor teeth deteriorates due to movement fluctuations
Solution Approach 1:
The cam ring's movement function is segmented from the tooth engagement function. The cam ring moves to adjust discharge amount, while separate guide pins and guide grooves maintain precise tooth engagement, dividing the functions to avoid interference between adjustment and precision requirements
Solution Approach 2:
Guide pins and guide grooves are introduced as intermediary elements between the cam ring and the rotors. These intermediaries constrain the cam ring's movement path, ensuring that adjustment movements do not compromise tooth engagement accuracy while still enabling discharge amount control
2Manufacturing precision
If high-accuracy processing is applied to tooth lines for precise engagement, then engagement accuracy improves, but device complexity and size increase
Solution Approach 1:
Guide pins and guide grooves serve as intermediary constraint mechanisms that simplify the tooth line design. Instead of requiring extremely precise tooth lines to maintain engagement accuracy during adjustment, the guide elements provide mechanical constraints that ensure accurate engagement even with standard processing tolerances
Solution Approach 2:
The guide pins and guide grooves provide pre-established geometric constraints that cushion against potential engagement errors. By defining the movement path beforehand, the system prevents engagement accuracy deterioration without requiring ultra-precise tooth line manufacturing
3Adaptability or versatility
If the cam ring is made movable for adjustment, then discharge amount control is enabled, but operational stability deteriorates due to pressure-induced position fluctuations
Solution Approach 1:
Guide pins and guide grooves act as intermediary constraint elements that stabilize the cam ring's position during pressure variations. The geometric constraints provided by these intermediaries prevent pressure-induced position fluctuations while allowing controlled movement for discharge adjustment
Solution Approach 2:
The guide structure provides pre-established geometric constraints that cushion against pressure-induced instabilities. By defining the cam ring's movement path in advance through guide pins and grooves, the system maintains positional stability during operation while still enabling discharge amount control
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
An oil pump includes: an inner rotor (12) rotatable with a drive shaft (11) in a unified manner on a drive-rotation axis (X); an outer rotor (13) which has inner teeth (13A) configured to engage with outer teeth (12A) of the inner rotor (12) and is rotatable about a driven axis (Y) eccentric to the drive-rotation axis (X); and an adjustment ring (14) for rotatably supporting the outer rotor (13). A guide means (G) which allows the adjustment ring (14) to rotate about the driven axis (Y), while allowing the driven axis (Y) to revolve about the drive-rotation axis (X), is formed of: first and second arm portions (C1,C2) provided on the adjustment ring (14); and first and second guide faces (S1) with which the first and second arm portions (C1,C2) are brought into slidable contact.