PVD-Coated Ball Socket Geometry for Low-Friction Lubrication
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Solution Overview
Problem
The formation of recessed portions for lubricating oil collection in ball socket structures reduces the effective sliding area, leading to increased friction and insufficient lubrication, especially at small tilt angles, which can result in higher coefficients of friction.
Innovation Solution
A ball socket structure with a PVD coating layer on the socket portion's sliding surface, featuring a shallow concave spherical design with a Ds/Rs ratio of 0.05 to 0.70, and optional chamfered outer periphery and through hole, to enhance uniform coating adhesion and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recessed portion is formed in the sliding surface for collecting lubricating oil, then lubrication is improved, but the effective sliding area is reduced and the coefficient of friction increases
Solution Approach 1:
The invention changes the geometric parameters of the sliding surface by forming a shallow concave spherical surface with a specific depth-to-radius ratio (Ds/Rs = 0.05 to 0.70). This parameter optimization allows the surface to maintain adequate lubrication oil collection while preserving sufficient effective sliding area, thereby resolving the contradiction between lubrication performance and friction coefficient.
2Quantity of substance
If a recessed portion is formed in the sliding surface, then lubricating oil collection is enhanced, but the coefficient of friction increases due to reduced sliding area
Solution Approach 1:
The invention optimizes the geometric parameters of the sliding surface by forming a shallow concave spherical surface with a specific depth-to-radius ratio (Ds/Rs = 0.05 to 0.70). This parameter optimization ensures adequate lubricating oil collection while preserving sufficient effective sliding area, thereby resolving the contradiction between lubrication performance and friction coefficient.
3Area of stationary object
If the sliding surface is made very shallow to maintain large area, then effective sliding area is preserved, but lubricating oil collection becomes insufficient
Solution Approach 1:
The invention determines the optimal range for the depth-to-radius ratio (Ds/Rs = 0.05 to 0.70) of the concave spherical surface. This optimized parameter range ensures that the sliding surface is shallow enough to maintain large effective sliding area while being deep enough to collect sufficient lubricating oil, resolving the contradiction between area preservation and lubrication adequacy.
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 PVD coating layer reduces the coefficient of friction and ensures uniform film thickness and durability, eliminating the need for recessed portions and improving sliding performance.
Implementation Method 1
the socket portion includes a sliding surface including a PVD coating layer
Data Source
Figure 1(A)~1(B)
Figure 2(A)~2(B)
Figure 3
AI summary
Object: A novel configuration of a ball socket structure with an enhanced socket portion (43) is proposed. Resolution means: A ball socket structure of the invention includes a ball portion (41) and a socket portion (43), the ball portion (41) and the socket portion (43) are configured to slide against one another. The socket portion (43) includes a sliding surface (43a) including a PVD coating layer (433), the sliding surface (43a) of the socket portion (43) is a concave spherical surface, and a value (Ds/Rs) of a ratio between a depth Ds of the sliding surface (43a) and a radius of curvature Rs of the sliding surface (43a) is from 0.05 to 0.70.