Ball Joint Housing Compression After Plastic Cure Shrinkage
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Solution Overview
Problem
Existing methods for producing ball joints fail to optimize sliding properties between the inner housing and the joint ball due to shrinkage of plastic compounds during hardening, leading to a loose fit of the inner housing in the outer housing.
Innovation Solution
The method involves compressing the outer housing to close the gap between it and the inner housing after the plastic compound hardens, allowing for the use of plastics that provide low sliding friction, ensuring a firm seat of the inner housing in the outer housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic compound that shrinks considerably during curing is used to optimize sliding friction, then the sliding properties between the inner housing and the ball joint are improved, but the inner housing no longer fits tightly in the outer housing after curing
Solution Approach 1:
The outer housing is pre-compressed before the plastic compound cures, creating initial contact pressure. This preliminary compression ensures that when the plastic shrinks during curing, the housings remain tightly fitted while the plastic can still provide optimal sliding properties.
Solution Approach 2:
The compression force applied to the outer housing is controlled and adjusted to achieve the optimal balance between maintaining tight fit and allowing sufficient shrinkage for low-friction sliding. By changing the compression parameter, both contradictory requirements are satisfied.
2Manufacturing precision
If a plastic compound that does not shrink or shrinks minimally is used, then the inner housing fits securely in the outer housing, but the sliding friction between the inner housing and the ball joint is not optimized
Solution Approach 1:
By applying compression to the outer housing before the plastic cures, we create a preliminary tight fit that compensates for the minimal shrinkage of the plastic compound, ensuring secure fitting while allowing the use of low-friction plastics.
Solution Approach 2:
The compression parameter is adjusted to achieve optimal sliding friction with plastics that have minimal shrinkage, allowing these materials to be used effectively while maintaining secure fit.
3Reliability
If the plastic compound is allowed to shrink during curing, then optimal sliding friction is achieved, but a gap forms between the outer housing and the inner housing
Solution Approach 1:
The outer housing is compressed before curing to close any gaps that may form during shrinkage. This preliminary compression ensures that even when the plastic shrinks to achieve optimal sliding properties, the housings remain in tight contact without gaps.
Solution Approach 2:
The compression force acts as a preliminary counter-action to the shrinkage force, preventing gap formation while allowing the plastic to shrink sufficiently to achieve optimal sliding friction properties.
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 enables the use of plastics with improved sliding properties while maintaining a secure fit, enhancing the performance of ball joints by reducing friction and ensuring proper seating.
Implementation Method 1
the plastic compound, which then hardens and, in its hardened state, forms the inner housing
Implementation Method 2
a plastic compound is introduced into the free space, thereby enclosing the ball joint with the plastic compound, which then hardens
Implementation Method 3
after hardening by compressing the outer housing, in particular permanently. The outer housing is deformed or reshaped by compression in such a way that the gap between the outer and inner housings closes
Implementation Method 4
plastic compounds that result in optimal sliding friction between the inner housing and the ball joint shrink considerably during curing
Data Source
Figure 1
Figure 2~4
Figure 3
AI summary
The invention relates to a method for producing a ball joint (1) which has an outer housing (3) that is provided with an outer housing pin opening (2), an inner housing (5) that is arranged in the outer housing (3) and is provided with an inner housing pin opening (4), and a ball pin (7) that comprises a joint ball (6) movably mounted in the inner housing (5) and extends out of the inner housing (5) through the inner housing pin opening (4), wherein - the ball pin (7) is introduced into the outer housing (3), and the joint ball (6) of the ball pin is positioned in the outer housing such that a free space encircling the joint ball (6) and/or the ball pin (7) remains between the outer housing (3) and the ball pin (7) and the ball pin (7) extends through the outer housing pin opening (2) out of the outer housing (3), - the free space is then filled with a plastic compound, and in the process the joint ball (6) is surrounded by the plastic compound which subsequently cures and forms the inner housing (5) in the cured state, and - a gap (19) which is formed between the outer housing (3) and the inner housing (5) when the plastic compound is cured is closed by compressing the outer housing (3) after the curing process.