Internal Gear Pump Outer Ring Cam Protrusions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable-capacity internal gear pumps face challenges in achieving high precision manufacturing due to the need for complex casting and cutting processes, which increase costs and time, and are prone to contamination issues that can disrupt smooth operation.
Innovation Solution
The design incorporates an outer ring with cam protruded parts and pins that guide the outer rotor along a predetermined locus, allowing for precise adjustment of discharge quantity without requiring high dimensional precision in the pump housing, and includes a space between pins and the rotor chamber to prevent contamination accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pump housing is manufactured by casting aluminum alloy with concave shape portions and convex shape portions for guiding the outer rotor, then the structural integration is improved, but the manufacturing precision and cost are worsened due to the difficulty of achieving ±20 μm to ±30 μm precision by casting alone
Solution Approach 1:
The guiding function is segmented into two separate components: the pump housing provides the concave guide groove, and a separate adjusting ring provides the convex guide pins. This segmentation allows each component to be manufactured with lower individual precision requirements while maintaining the overall guiding precision through their配合 (coordination). The adjusting ring can be precisely manufactured and then assembled to the pump housing, separating the precision requirement from the casting process.
Solution Approach 2:
The adjusting ring serves as an intermediary component between the pump housing and the outer rotor. Instead of directly forming the precision guiding features in the pump housing casting, the adjusting ring is introduced as a separate precision component that interfaces with both the housing (via the guide groove) and the outer rotor (via guide pins), mediating the precision requirement.
2Adaptability or versatility
If the outer ring is oscillated to move the outer rotor along a circular locus for variable capacity control, then the discharge quantity adjustment capability is improved, but the device complexity increases due to the additional oscillation mechanism
Solution Approach 1:
The adjusting ring serves multiple functions: it provides the convex guide pins for guiding the outer rotor's circular locus movement, and it is itself oscillated by the oscillation mechanism to achieve variable capacity control. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall device complexity despite the variable capacity capability.
Solution Approach 2:
The guiding function (providing guide pins) and the oscillation function (being oscillated for capacity control) are merged into a single component - the adjusting ring. This merging reduces the number of separate parts and simplifies the overall structure while maintaining both the variable capacity capability and the guiding function.
3Device complexity
If contaminants adhere to the concave shape portions such as guide grooves, then the contamination trapping is worsened, but the structural simplicity is improved by using integrated casting
Solution Approach 1:
The adjusting ring with its convex guide pins is extracted as a separate component from the pump housing. This extraction eliminates the problem of contaminants being trapped in the concave guide groove of the housing, as the convex pins of the adjusting ring make contact without requiring the housing to have deep concave features that trap contaminants. The guiding function is achieved through the protruding pins rather than recessed grooves.
4Manufacturing precision
If cutting work is performed on the cast aluminum alloy to achieve high dimensional precision, then the manufacturing precision is improved, but the manufacturing time and cost are worsened
Solution Approach 1:
The manufacturing process is segmented into casting the pump housing (without precision cutting) and separately manufacturing the adjusting ring (which can be precisely manufactured). This segmentation allows the precision requirements to be concentrated on the smaller adjusting ring component rather than requiring extensive cutting work on the entire pump housing, thereby reducing overall manufacturing time while achieving the required precision.
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
This configuration enables accurate and efficient adjustment of discharge quantity while reducing manufacturing complexity and costs, and prevents contamination from adhering to the moving parts, ensuring smooth operation and extended durability.
Implementation Method 1
an outer ring (5) that includes a holding-inner peripheral part (51) rotatably holding the outer rotor (4) and that has at least three cam protruded parts (53) formed along a circumferential direction of an outer periphery surface (52) of the outer ring (5)
Data Source
AI summary
The internal gear pump according to the present invention includes: an inner rotor; an outer rotor that rotates with predetermined eccentricity to a rotation center of the inner rotor; an outer ring that rotatably holds the outer rotor, and has at least three cam protruded parts formed; a pump housing that has a rotor chamber; pins in the same number as that of the cam protruded parts; and operation means for oscillating the outer ring. Positions of the pins are set so that a diameter center of the holding-inner peripheral part of the outer ring is moved by the operation means along a locus of a circle, the radius of which is the eccentricity to the rotation center of the inner rotor.