Universal Joint Anti-Backlash Design with Press-Fit Ball Bearings
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Solution Overview
Problem
Existing universal joints for transmitting rotational forces, such as those used in drum pedal linkage systems, face issues like increased cost and longer assembly times due to sizing variations introduced by needle bearings, and inefficiencies from lateral movement and backlash caused by split rings or bushings.
Innovation Solution
A universal joint design featuring a spider operatively coupled to trunnions and yokes with ball bearings press-fit into openings, where shoulders prevent lateral movement and allow for a single size of trunnions, reducing manufacturing complexity and enhancing anti-backlash performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If needle bearings are used in the universal joint, then bearing capacity is improved, but sizing variations occur that require multiple trunnion sizes, increasing cost and assembly time
Solution Approach 1:
The patent changes the bearing type from needle bearings to ball bearings, which have more consistent dimensional parameters and tolerances. This allows all trunnions to be manufactured to a single size specification, eliminating the need for multiple trunnion sizes while maintaining adequate bearing capacity through the ball bearing mechanism.
2Ease of manufacture
If split rings or bushings are used in the universal joint, then ease of assembly is improved, but lateral movement and backlash occur that reduce efficiency
Solution Approach 1:
The patent employs spherical ball bearings within the trunnion-boss interface. The spherical geometry provides natural self-centering that prevents lateral movement of the yokes, while the curved contact surfaces eliminate backlash by maintaining continuous positive contact between the ball bearings and the trunnion/boss interfaces.
3Ease of manufacture
If a single size of trunnions is used, then manufacturing complexity and cost are reduced, but bearing capacity may be compromised
Solution Approach 1:
The patent extracts the bearing function from the trunnion component itself, placing ball bearings in separate openings within the spider. This allows the trunnions to be simplified to a single size for structural support, while the bearing capacity function is handled by the dedicated ball bearings, which can be precisely manufactured to consistent specifications.
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 design simplifies manufacturing and assembly, reduces costs by allowing a single trunnion size, and improves rotational efficiency by minimizing backlash and lateral movement, leading to a more reliable and efficient energy transfer.
Implementation Method 1
The spider further may include a plurality of openings, each opening receiving a ball bearing. The ball bearings may be one or more of the following: single row bearings, deep groove bearings, and shielded bearings.
Implementation Method 2
Each opening may include a shoulder configured to abut the ball bearing in a radial direction, e.g., by extending radially inward from an outer surface of the spider.
Implementation Method 3
Each of the trunnions may be press fit into a respective ball bearing and into a respective opening in the bosses. Similarly, each ball bearing may be press fit into a respective one of the plurality of openings.
Data Source
AI summary
A universal joint includes a spider operatively coupled to two pairs of trunnions, each pair of trunnions having an axis. The spider includes first and second portions that may substantially bisect the spider along a plane containing the axes. The joint further may include a pair of yokes, each yoke having a shaft and a pair of bosses, and each pair of bosses may receive the distal parts of a corresponding pair of trunnions. The spider further may include a plurality of openings, each opening receiving a ball bearing. Each opening in the spider may include a shoulder configured to abut the ball bearing in a radial direction, e.g., by extending radially inward from an outer surface of the spider. The trunnions may be press fit into the bearings and the bosses, and the bearings may be press fit into the spider openings, thereby eliminating backlash in the universal joint.