Resin Cage Column Design for Angular Contact Ball Bearing Strength
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Solution Overview
Problem
The mechanical strength of resin cages for angular contact ball bearings is compromised when trying to increase the number of balls held, as the thinnest portion of the column portions is not sufficient to support the load, limiting the load carrying capacity without increasing the bearing size.
Innovation Solution
The resin cage design adjusts the connection position of the column portion radially outward section to a position radially outward of the pitch circle, increasing the thickness of the column portion radially inward section at this point, enhancing mechanical strength and allowing more balls to be held with the same pitch circle diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the parting line of the mold coincides with the pitch circle position, then the manufacturing process is simplified, but the mechanical strength of the column portion is insufficient
Solution Approach 1:
The parting line is repositioned from the pitch circle position (radial dimension) to a position radially outward of the pitch circle, changing the dimensional reference for mold separation. This allows the column portion to maintain adequate thickness at the connection position while still enabling mold opening, thus resolving the contradiction between manufacturing ease and structural strength.
2Strength
If the thickness of the column portion radially inward section is increased to ensure mechanical strength, then the column portion can support the load, but the number of balls that can be held is reduced
Solution Approach 1:
The column portion is designed with non-uniform thickness distribution: the radially inward section maintains minimal thickness to maximize ball capacity, while the radially outward section (at the connection position) has increased thickness to ensure mechanical strength. This localized differentiation allows the structure to satisfy both strength requirements and ball capacity requirements simultaneously.
3Quantity of substance
If the number of balls is increased to enhance load carrying capacity, then the load carrying capacity improves, but the interval between balls decreases, reducing the thickness of the column portion
Solution Approach 1:
The column portion thickness is differentiated into two functional zones: the radially inward section has minimal thickness to accommodate higher ball density, while the radially outward connection section has enhanced thickness to maintain structural integrity. This allows increased ball count without compromising the strength of the connection portion.
Solution Approach 2:
The solution moves the critical connection structure radially outward from the pitch circle position, creating a spatial separation between the ball housing region (where thin columns maximize ball count) and the connection region (where thick columns ensure strength). This dimensional relocation resolves the trade-off between ball density and structural strength.
Data Source
AI summary
A cage has a ring portion, and a plurality of column portions that protrude from the ring portion, that are arranged in the circumference direction. Each column portion has a column portion radially inward section that forms a bearing-radial-direction inward side portion, and a column portion radially outward section that is connected to the radially inward section at its radially outer end position, so as to protrude on both sides in the circumferential direction from the radially inward section. A connection position at which the radially outward section is connected to the radially inward section is adjusted to a position radially outward of a pitch circle position of the plurality of the balls that are held in the respective pockets. Thus, the thickness of the radially inward section at the connection position is larger than the thickness of the radially inward section at the pitch circle position.