Spur Gear Differential with Profile-Shifted Sun Gears
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Solution Overview
Problem
Existing spur gear differentials require significant axial installation space and weight due to the conventional design of sun gears and planet gears, which limits their compactness and efficiency.
Innovation Solution
The design incorporates a spur gear differential with a first and second sun gear, where the planet gears of one set have wider teeth engaging with both suns, and the planet gears of the other set have narrower teeth, utilizing profile displacement to avoid tooth collision, with different crown-circle diameters for each sun gear, allowing for reduced axial space and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sun gear and planet gear design is used, then reliable tooth engagement is achieved, but axial installation space and weight increase
Solution Approach 1:
The patent applies profile displacement to the sun gear teeth, changing the radial position parameter of the teeth from the reference circle to a displaced crown circle. This parameter change allows the planet gears to engage with both sun gears simultaneously while reducing the axial distance required for the gear arrangement, thus resolving the contradiction between reliable tooth engagement and reduced axial installation space
2Reliability
If conventional sun gear and planet gear design is used, then reliable tooth engagement is achieved, but weight increases
Solution Approach 1:
By displacing the sun gear teeth radially outward to a larger crown circle diameter, the patent creates a more efficient gear arrangement that reduces the number and size of components needed. This parameter change in tooth position enables weight reduction while maintaining reliable tooth engagement between the planet gears and both sun gears
3Ease of manufacture
If the number of teeth of both suns is made equal, then manufacturing simplicity is improved, but tooth collision occurs without profile displacement
Solution Approach 1:
The patent applies profile displacement by moving the sun gear teeth from the reference circle to a displaced crown circle. This parameter change in radial position allows both sun gears to have the same number of teeth for manufacturing simplicity while preventing tooth collision through the radial offset, thus resolving the contradiction between ease of manufacture and reliable tooth engagement
Data Source
AI summary
A spur gear differential (1) having a first sun (3) and a second sun (5), wherein the first sun (3) is associated with a first set of planetary gears (7) and the second sun (5) is associated with a second set of planetary gears (9), and the first set of planetary gears (7) engages with the second set of planetary gears (9). The number of teeth (11) of the first sun (3) are equal to the number of teeth (12) of the second sun (5), and the teeth (11) of the first sun (3) are disposed by a profile shift on a crown circle (2) having a crown circle diameter (DK1) that differs from the crown circle diameter (DK2) of a crown circle on which the teeth (12) of the second sun (5) are disposed. The first set of planetary gears (7) engages only with the first sun (3) and the second set of planetary gears (9) engages only with the second sun (5).