Ball Pin Oxide Layer Wear Protection
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Solution Overview
Problem
Existing ball pins face a mutual exclusion between nitriding for corrosion protection and surface layer hardening for wear resistance and fatigue strength, leading to premature wear and corrosion issues under static loading and micro-movements.
Innovation Solution
A steel ball pin with an oxide layer in the bearing contact area, eliminating the need for nitriding and allowing for surface layer hardening, which provides improved wear and corrosion protection without the costs and process complexities of nitriding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nitriding is applied to the ball pin surface, then corrosion protection is improved, but surface layer hardening is impaired due to high process temperatures
Solution Approach 1:
The ball pin surface is divided into two distinct treatment zones: the sealing bellows sealed area receives nitriding treatment for corrosion protection, while the bearing contact area is excluded from nitriding to allow subsequent surface hardening. This spatial segmentation resolves the contradiction by applying different surface treatments to different functional areas of the same component.
Solution Approach 2:
Different surface properties are applied to different regions of the ball pin according to their specific functional requirements. The sealing area receives corrosion-resistant nitrided surface, while the bearing contact area receives a hardenable surface structure. This local differentiation allows each area to optimize its performance without compromising the other.
2Strength
If surface layer hardening is applied to the ball pin, then wear resistance and fatigue strength are improved, but nitriding protection is destroyed
Solution Approach 1:
The surface treatment process is segmented so that nitriding is applied only to the sealing bellows sealed area, while the bearing contact area is deliberately excluded. This allows surface hardening to be applied subsequently to the bearing area without affecting the nitrided corrosion-protected zones, thereby resolving the mutual exclusion between these two treatments.
Solution Approach 2:
Nitriding is performed as a preliminary treatment on specific areas before surface hardening. By pre-nitriding the sealing areas and excluding the bearing contact area from nitriding, the process sequence is optimized to preserve corrosion protection where needed while enabling hardening where wear resistance is critical.
3Object-affected harmful factors
If nitriding and oxidation are applied to the ball pin, then corrosion protection is enhanced, but wear resistance under static loading and micro-movements is insufficient
Solution Approach 1:
The ball pin surface is segmented into areas with different treatment combinations: the sealing bellows sealed area receives nitriding plus oxidation for maximum corrosion protection, while the bearing contact area receives only oxidation (or no surface treatment) to maintain wear resistance under static loading and micro-movement conditions.
Solution Approach 2:
Different surface properties are tailored to local functional requirements: corrosion resistance is maximized in the sealing area through nitriding and oxidation, while wear resistance is optimized in the bearing contact area by avoiding nitriding and its associated porous structure that performs poorly under boundary lubrication conditions.
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
The oxide layer enhances wear resistance and corrosion protection, enabling ball pins to withstand high static loads and micro-movements with improved fatigue strength and reduced production costs, overcoming the mutual exclusion of previous technologies.
Implementation Method 1
a ball pin (1) made of steel and having no nitrided layer at least in the bearing contact area (6) between the joint ball (1) and the bearing shell
Data Source
AI summary
A ball joint with a ball pin and a steel ball pin with a joint ball. The ball joint and ball pin are suitable for use when solid-on-solid friction predominates, for example under high static pre-loading or under high operational loads and with small joint movements. At least in a bearing contact area, between the joint ball and the bearing shell, does not include any nitrided layer. The surface of the ball pin has an oxide layer, provided as wear protection, at least in the bearing contact area of the joint ball. The oxide layer in the ball joints, previously regarded (as part of the nitriding treatment) as only improving corrosion protection functions as a form of wear protection. Thus, the mutual exclusion between increasing the fatigue strength (by surface layer hardening) and improving the wear resistance (by nitriding/oxidation) is overcome with such ball pins.