Torsional Welding Closure Element for Hydraulic Accumulators

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Solution Overview

Problem

Existing hydraulic devices face challenges with costly and space-intensive connection methods for closure elements, which can lead to leaks and increased dimensions due to the need for additional sealing and support components, particularly in low-pressure accumulators used in vehicle brake systems.

Innovation Solution

The method employs torsional welding using a sonotrode to create a fluid-tight and gas-tight connection between the closure element and the housing by plastic deformation, eliminating the need for screws, O-rings, and calking processes, thereby reducing material requirements and production costs while ensuring a secure, non-detachable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional connecting techniques (screws, circlips, calking) are used to attach the closure element to the housing, then the connection can be easily assembled and disassembled, but the device complexity increases due to additional components and the space requirement increases due to the need for sealing elements and support structures

Engineering Contradiction:

Improveease of assemblyVSAvoidnumber of components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the closure element directly with the housing through torsional welding, combining two separate components into a unified structure. This eliminates the need for additional fastening elements (screws, circlips) and sealing components (O-rings), thereby reducing device complexity while maintaining assembly effectiveness through the welding process itself

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts and removes unnecessary intermediate components from the traditional assembly. By using torsional welding, the patent eliminates sealing elements, support rings, threads, and calking materials that would otherwise be required in conventional connecting techniques, simplifying the overall structure

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If traditional connecting techniques with additional sealing components are used, then sealing can be achieved, but the space requirement increases and production costs increase

Engineering Contradiction:

Improvesealing performanceVSAvoidspace requirement

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The closure element and housing are merged into a single welded structure, eliminating the need for separate sealing components like O-rings. The welding process itself creates the seal, reducing the space required for sealing elements while maintaining reliable sealing performance through the direct metallic bond

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical sealing system (O-rings, gaskets, sealing surfaces) with a metallurgical bonding system. The torsional welding process creates both the structural connection and the seal simultaneously, eliminating the need for mechanical sealing components and their associated space requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If screws or connecting means are used to attach the closure element, then the connection can be assembled precisely, but the production costs increase and the overall dimensions increase

Engineering Contradiction:

Improveconnection precisionVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates expensive connecting means (screws, threaded inserts, precision-machined interfaces) from the assembly. The torsional welding process achieves precise connection through direct material fusion, removing the need for costly precision machining and specialized fastening components

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a cost-effective welding process that uses consumable energy (ultrasonic vibration) rather than expensive reusable precision components. The welding method requires minimal tooling and produces a permanent bond without the need for expensive precision-machined mating surfaces or high-strength fasteners

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Strength

If calking or deformation processes are used to secure the closure element, then a tight connection is achieved, but material requirements increase and axial forces during assembly increase

Engineering Contradiction:

Improveconnection strengthVSAvoidmaterial requirement

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent replaces the mechanical deformation system (calking, pressing, forming) with a vibrational welding system. The torsional welding process uses high-frequency vibration to generate friction heat and plastic flow at the interface, creating a strong bond without requiring excessive axial forces or additional material for deformation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the physical parameters of the welding process by using high-frequency vibration (typically 20-40 kHz) to alter the material behavior at the interface. This vibrational energy reduces the flow stress of the materials during bonding, enabling strong connections with lower axial forces and minimal material deformation

Inventive Principle:

Principle #35Parameter changes

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 results in a leak-tight, space-saving connection that maintains integrity over the device's service life, reduces material usage, and lowers production costs by eliminating the need for additional components and support structures, while also reducing noise and weight, and enhancing the structural stability of the hydraulic device.

Implementation Method 1

The method employs torsional welding using a sonotrode to create a fluid-tight and gas-tight connection between the closure element and the housing by plastic deformation

Methodology Applied

Scientific EffectTorsional friction welding: Friction Welding