Ultrasonic Welded Drive Cable Terminal Cap
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Solution Overview
Problem
Drive cables used in motor vehicles, particularly those with tilting and sliding roofs or roller blinds, face issues such as wire fanning out, rattling noises, and insufficient adhesion of end caps due to existing manufacturing methods, which lead to increased costs and complexity.
Innovation Solution
A method involving surface ultrasonic welding of an end cap onto a drive cable, where the pitch helix is ground conically to facilitate even coverage and connection, using a sonotrode that contacts the entire outer surface of the end cap to ensure uniform heating and bonding, thereby preventing wire fanning and rattling while enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If metal sleeves are hammered onto the drive cable end, then wire fanning is prevented, but rattling noises occur due to metal contact
Solution Approach 1:
The patent replaces durable metal sleeves with disposable plastic end caps that are ultrasonically welded to the drive cable. The plastic caps provide sufficient functionality for wire containment without the harmful metal-to-metal contact that causes rattling noises during operation.
Solution Approach 2:
The patent replaces the mechanical hammering process with ultrasonic welding technology. Instead of forcibly driving metal sleeves onto the cable end using impact forces, the invention uses high-frequency vibrations to melt and bond the plastic cap to the cable, eliminating impact-related noise and providing a more precise connection.
2Object-generated harmful factors
If plastic sleeves are molded directly onto the drive cable end, then rattling is reduced, but adhesion is insufficient due to oil residues
Solution Approach 1:
The patent replaces injection molding with ultrasonic welding technology. Ultrasonic welding uses high-frequency mechanical vibrations to locally melt and bond the plastic cap to the cable end, creating a strong adhesive joint without requiring the entire cable end to be free of oil residues, thus maintaining reliability while reducing rattling.
Solution Approach 2:
The patent applies ultrasonic welding at specific localized points on the cable end rather than requiring complete surface cleanliness. The high-energy ultrasonic vibrations create effective bonds at the contact areas between the cap and cable, allowing oil residues in non-critical areas to remain without compromising adhesion strength.
3Extent of automation
If injection molding is used for end sleeves, then production is automated, but plastic material migrates along the pitch helix and hardens causing rattling
Solution Approach 1:
The patent replaces the injection molding process with ultrasonic welding. Ultrasonic welding involves bringing the pre-formed plastic cap into contact with the cable end and applying high-frequency vibrations to create a bond, rather than injecting molten plastic under high pressure. This eliminates the plastic migration issue while maintaining automation through programmable welding parameters and fixture positioning.
4Loss of time
If spot ultrasonic welding is used with a small-area sonotrode, then welding time is reduced, but welding burrs are formed causing rattling noises
Solution Approach 1:
The patent transitions from point-contact spot welding to surface-contact welding by using a sonotrode that matches the outer contour of the end cap. This dimensional change from 0D point contact to 2D surface contact distributes the ultrasonic energy across the entire bonding interface, preventing localized overheating and burr formation while maintaining efficient welding speeds through increased contact area.
5Reliability
If the pitch helix is removed to expose the cable core for cap placement, then adhesion is improved, but sharp edges are created causing noises and damage
Solution Approach 1:
The patent applies preliminary conical grinding to the cable end surface before cap placement. This pre-treatment creates a tapered seating surface that improves cap alignment and adhesion while eliminating sharp edges. The conical shape allows the cap to seat properly on the cable core without requiring complete helix removal, thus achieving good adhesion without creating harmful sharp edges.
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 method reduces manufacturing costs, prevents wire fanning and rattling, and ensures a strong, durable connection between the end cap and the drive cable, eliminating the formation of burrs and improving the overall performance and reliability of the drive cable.
Implementation Method 1
at least one end (11) of the drive cable (1) is provided with an end cap (2) and connected to it by ultrasonic surface welding
Implementation Method 2
the pitch helix (4) is ground conically to facilitate even coverage and connection, using a sonotrode that contacts the entire outer surface of the end cap to ensure uniform heating and bonding
Data Source
Figure 1~5
Figure 6~8
Figure 9
AI summary
Disclosed is a method for producing a drive cable (1), in particular for use in motor vehicles, such as in pop-up and/or sliding roofs or sun blind rollers, at least one end (11) of the drive cable (1) being provided with a terminal cap (2) and being connected thereto by ultrasonic welding, ultrasound being applied two-dimensionally, substantially across the entire outer surface (9) of the terminal cap (2), and a pitch helix (4) of the drive cable (1) being ground, in particular conically ground, in the region of the drive cable end (11), which is covered by the terminal cap (2), prior to connection to the terminal cap (2).