Staggered Gear Engagement Phase Reduces Transmission Error
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Solution Overview
Problem
Conventional power transmission apparatuses experience increased transmission error and vibration due to overlapping gear engagement phases, leading to image jitter in image forming apparatuses.
Innovation Solution
The power transmission apparatus is designed such that the gear engagement phases of driven gears are not overlapped by adjusting the number of teeth of the drive gear and the number of driven gears, ensuring that the phase difference between driven gears is maintained, thereby preventing overlapping and reducing torsional force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single drive gear is engaged with multiple driven gears at approximately 180 degrees installation angle, then the lateral force is reduced, but the transmission error increases significantly
Solution Approach 1:
The patent applies asymmetry by deliberately positioning the driven gears at non-symmetric angles relative to the drive gear. Instead of the conventional 180-degree symmetric arrangement, the driven gears are positioned at different angles (e.g., first driven gear at angle θ1, second driven gear at angle θ2 where θ1 ≠ θ2 and θ1 ≠ θ2 + 180°). This asymmetric positioning ensures that the gear engagement phases are staggered rather than overlapped, thereby reducing transmission error while maintaining acceptable lateral force levels.
Solution Approach 2:
The patent utilizes periodic action by distributing the gear engagement phases of multiple driven gears across different time periods during the rotation of the drive gear. By positioning driven gears at different angular intervals, the engagement and disengagement of teeth occurs in a staggered periodic sequence rather than simultaneously. This periodic distribution of engagement phases prevents the superposition of transmission errors and reduces overall vibration and noise.
2Force
If gear engagement phases are overlapped, then the lateral force is small, but torsional force acts significantly in the rotation direction
Solution Approach 1:
The asymmetric positioning of driven gears creates non-uniform engagement phases that prevent the simultaneous engagement of multiple tooth pairs at the same rotational position. This asymmetry in angular positioning ensures that torsional forces are distributed across different time periods rather than being superimposed, significantly reducing the peak torsional force acting on the drive gear shaft.
3Ease of manufacture
If transmission error increases due to overlapping gear engagement phases, then vibration and image jitter occur, but cost reduction is achieved by using one drive gear for multiple driven gears
Solution Approach 1:
The asymmetric angular positioning of driven gears provides a simple yet effective solution that maintains the cost benefits of using a single drive gear while eliminating the harmful effects of overlapping engagement phases. This positioning strategy requires no additional components or complex mechanisms, thus maintaining cost efficiency while significantly reducing vibration and image jitter.
Data Source
AI summary
A power transmission apparatus includes a drive gear disposed on a shaft of a motor; a plurality of driven gears disposed to be engaged with the drive gear; and a plurality of driven members configured to receive power from each of the plurality of driven gears, wherein the plurality of driven gears is arranged so that, when the plurality of driven gears are engaged with the drive gear, a gear engagement phase of each of the plurality of driven gears is different.