Constant Velocity Plunging Joint Track Alignment for Lower NVH
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing constant velocity plunging joints face inefficiencies and result in hardening distortions that affect the service life and NVH properties due to varying ball play in the tracks, leading to undesirable noise, vibration, and harshness.
Innovation Solution
The joint design involves pre-machining and hardening outer ball tracks, and producing inner ball tracks with a non-circular shape to match the distorted outer shape, ensuring precise alignment and reducing maximum ball play, with the inner joint part mounted at an angle less than 30° to the outer part, allowing for efficient assembly and improved NVH performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If outer ball tracks are mechanically finish-machined before hardening, then manufacturing precision is improved, but hardening distortions occur causing the outer ring line to become irregular
Solution Approach 1:
The patent applies preliminary anti-action by pre-machining the outer ball tracks to high precision before hardening, then compensating for the anticipated hardening distortions. The inner ball tracks are deliberately made non-circular with specific diameter variations that will counterbalance the irregularities introduced by hardening of the outer tracks, thereby maintaining overall operational precision.
Solution Approach 2:
The patent changes the geometric parameters of the inner ball tracks to compensate for hardening-induced distortions in the outer tracks. Specifically, the inner ring line is designed with a non-circular shape where the largest inner ring line diameter and smallest inner ring line diameter are deliberately varied to offset the irregular outer ring line shape, maintaining consistent ball play characteristics.
2Reliability
If inner ball tracks are produced with non-circular shape to compensate for outer track distortions, then service life is improved, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the geometric parameters of the inner ball tracks by deliberately creating a non-circular inner ring line shape. The largest and smallest inner ring line diameters are specifically designed to compensate for outer track variations, improving service life through reduced ball play while the parameters can be controlled during manufacturing.
Solution Approach 2:
The patent creates a complementary copy of the outer track irregularities in the inner tracks. By measuring or predicting the outer ring line irregularities and creating corresponding compensating irregularities in the inner ring line, the system achieves distortion compensation without requiring complex active control mechanisms.
3Object-generated harmful factors
If inner joint part is mounted at an angle less than 30° to reduce ball play, then NVH properties are improved, but alignment precision requirements increase
Solution Approach 1:
The patent applies preliminary anti-action by pre-aligning the inner and outer joint parts at a specific angular orientation (less than 30° between their respective largest ring line diameters) before assembly. This pre-alignment compensates for hardening-induced distortions and minimizes ball play, thereby improving NVH properties while establishing clear alignment criteria for manufacturing.
Solution Approach 2:
The patent introduces asymmetry in the assembly orientation by specifying a non-zero angle (less than 30°) between the largest inner ring line diameter and the largest outer ring line diameter. This asymmetric alignment optimizes the fit between compensated tracks, reducing ball play and improving vibration characteristics compared to a symmetric zero-degree alignment.
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 approach results in a joint with enhanced service life and improved NVH characteristics while maintaining efficient production, reducing manufacturing complexity and costs.
Implementation Method 1
at least partial sections of the outer ball tracks are hardened, wherein the outer ball tracks are mechanically finish-machined before hardening, that is, mechanically unmachined after hardening; wherein at least partial sections of the inner ball tracks are hardened and machined
Data Source
AI summary
A constant velocity plunging joint having an outer joint part, an inner joint part, balls which are arranged in pairs of tracks each comprising an outer ball track and an inner ball track, and a ball cage with circumferentially distributed cage windows, in each of which one of the balls is accommodated. An outer ring line through all ball centers on the outer ball tracks has an irregular shape with a largest and smallest outer ring line diameter. The inner ball tracks are produced in such a way that an inner ring line through all ball centers has an irregular shape with a largest and smallest inner ring line diameter, and wherein the inner joint part is mounted relative to the outer joint part such that an angle formed between the largest inner ring line diameter and the largest outer ring diameter is smaller than 30°.