Compensating Bush With Alternating Resistance Zones For Fastening
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Solution Overview
Problem
Existing devices for fastening add-on parts to carrier parts face challenges with large tolerances between the compensating bush and screw shank, requiring high tightening torques and limiting material variability due to differences in mechanical properties.
Innovation Solution
The compensating bush features a head section with alternating zones of high and low radial resistance, allowing for flexibility and accommodating similar materials for the fastening screw and compensating bush, while the screw shank cuts a thread into the bush until secure connection is achieved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screw shank is made harder than the compensating bush to cut threads, then secure fastening is achieved, but high tightening torques are required and material variability is limited
Solution Approach 1:
The head section of the compensating bush is designed with alternating zones of different radial resistance, creating local variations in material properties. This allows the bush to accommodate the screw shank with lower torque while maintaining secure fastening through the differentiated zones that guide and support the threading process.
Solution Approach 2:
The compensating bush employs varying radial resistance parameters along its head section, transitioning from uniform material properties to a structured pattern of alternating high and low resistance zones. This parameter variation enables the bush to adapt to the screw shank during installation, reducing the required tightening torque while ensuring reliable connection.
2Manufacturing precision
If the screw shank is made harder than the compensating bush to cut threads, then thread formation is achieved, but material variability is limited
Solution Approach 1:
By implementing alternating zones of high and low radial resistance in the head section, the compensating bush achieves effective thread formation through localized material interaction rather than relying on the screw shank being harder than the entire bush. This enables greater material variability in both components.
Solution Approach 2:
The head section's alternating resistance zones create a dynamic interaction during screw insertion, where the varying radial resistance adapts to the screw shank's progression. This dynamic mechanism ensures reliable thread formation regardless of material hardness differences, expanding material selection flexibility.
3Ease of manufacture
If large tolerances exist between channel section and screw shank diameters, then manufacturing flexibility increases, but high tightening torques are required
Solution Approach 1:
The alternating zones of radial resistance in the head section create a progressive engagement mechanism that accommodates diameter tolerances. As the screw shank advances, it sequentially engages zones with different resistance, allowing the system to absorb dimensional variations without requiring excessive tightening torque.
Solution Approach 2:
The structured alternating zones in the head section act as a pre-designed cushioning mechanism that anticipates and compensates for diameter tolerances before the screw reaches the final tight position. This beforehand cushioning reduces the peak torque required during installation.
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 solution enables secure fastening with low tightening torques and allows for a wide range of material choices, effectively compensating for diameter tolerances and ensuring a stable connection.
Implementation Method 1
the screw shank initially cuts a thread in the channel section until the torque required for this is greater than the torque required to unscrew the compensating bush
Implementation Method 2
the compensating bush has a head section with an alternating sequence of zones with a relatively high resistance to radial expansion and zones with a comparatively low resistance to radial expansion
Data Source
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AI summary
A device for fastening an add-on part (23) and a support part (24) at a distance from each other has a mounting nut (1) comprising an internal thread (9) of a first direction of thread, a compensating bush (5) comprising an external thread (8) that is adjusted to the internal thread (9), and a fastening screw (26), wherein its screw shaft (25) is configured having an external thread (27) of a second direction of thread opposite of the first direction of thread. The compensating bush (5) is configured having an internal sleeve (13) comprising a head section (15) having an arrangement of reinforcement zones (17) and adaptation zones (18), wherein the reinforcement zones (17) have a larger resistance than the adaptation zones (18) as opposed to an expansion directed radially outward. In this manner, relatively low tightening torques, as well as a relatively large variability in the material selection, are achieved even with relatively large tolerances between the diameters of the channel section of the compensating bush and the screw shaft.