Cast Trailing Arm with Weldable Steel Sleeve

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing suspension units for vehicles, particularly those with rigid axles, are costly and prone to production errors when made from weldable materials, and can only withstand limited mechanical loads due to complex cast steel requirements.

Innovation Solution

A suspension unit comprising a trailing arm made of cast or composite material with a hollow cylinder element of weldable material, where the hollow cylinder element is positively and/or non-positively connected to the trailing arm, allowing for high torque and force transmission, and enabling the use of proven welding methods without the need for expensive cast steel or complex machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the trailing arm is made from weldable material (e.g., cast steel), then the suspension unit can withstand high mechanical loads, but the production cost increases and the error rate (susceptibility to cavities) increases due to complicated casting

Engineering Contradiction:
Improvemechanical load capacityVSAvoidproduction error rate
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The suspension unit is divided into two distinct parts: a trailing arm made from cast material (which can be aluminum or other materials) and a hollow cylinder element made from weldable material. This segmentation allows each component to be optimized for its specific function and manufacturing process, avoiding the need to make the entire trailing arm from expensive cast steel while still achieving high strength where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines different materials - a cast trailing arm (which can be aluminum or other cost-effective materials) with a weldable hollow cylinder element (such as steel). This composite approach allows the suspension unit to achieve the strength and weldability of steel in critical load-bearing areas while using more cost-effective materials for the trailing arm body, thereby reducing production costs and improving reliability.

Inventive Principle:
Principle #40Composite materials

2Strength

If the trailing arm is made from cast steel to achieve high strength, then the suspension unit can absorb high forces, but the production cost increases

Engineering Contradiction:
Improveforce absorption capacityVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The suspension unit is divided into two distinct parts: a trailing arm made from cast material (which can be aluminum or other materials) and a hollow cylinder element made from weldable material. This segmentation allows each component to be optimized for its specific function and manufacturing process, avoiding the need to make the entire trailing arm from expensive cast steel while still achieving high strength where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines different materials - a cast trailing arm (which can be aluminum or other cost-effective materials) with a weldable hollow cylinder element (such as steel). This composite approach allows the suspension unit to achieve the strength and weldability of steel in critical load-bearing areas while using more cost-effective materials for the trailing arm body, thereby reducing production costs and improving reliability.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If non-positive connection (clamping or screwing) is used between trailing arm and vehicle axle, then the production process is simplified, but the mechanical load capacity is limited

Engineering Contradiction:
Improveproduction process simplicityVSAvoidmechanical load capacity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention merges two connection approaches: the hollow cylinder element is positively connected to the vehicle axle (enabling high mechanical load capacity), while the trailing arm is non-positively connected to the hollow cylinder element (maintaining production simplicity). This combination achieves both high strength and ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hollow cylinder element acts as an intermediary component between the trailing arm and the vehicle axle. It provides a positive connection to the axle for high load capacity while receiving the trailing arm through a simpler non-positive connection, thereby mediating between the requirements for strength and ease of manufacture.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If the hollow cylinder element is surrounded by the trailing arm, then high torques and forces can be transmitted, but the complexity of the connection increases

Engineering Contradiction:
Improvetorque and force transmissionVSAvoidconnection complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The hollow cylinder element is nested within the trailing arm structure, with the trailing arm surrounding the hollow cylinder element in certain areas. This nesting arrangement enables high torque and force transmission through the combined structure while keeping the connection relatively simple, as the trailing arm can be cast or formed around the hollow cylinder element in a single manufacturing process.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP1989069B1Cast member having an integrated steel sleeve
Publication Date: 2010.06.02 SAF HOLLAND GMBH
  • EP1989069B1 patent drawingFigure 1
  • EP1989069B1 patent drawingFigure 2
  • EP1989069B1 patent drawingFigure 3

AI summary

The invention relates to a suspension unit for a vehicle, in particular motor vehicle, having a rigid axle, comprising a longitudinal member (2) or axle member having a suspension section (8), a support section (10) and an axle receptacle section (12), wherein the suspension section is designed to be rotatably or pivotably articulatedly mounted on a frame element of the vehicle, the longitudinal member can be supported on the frame element by means of the support section, and the vehicle axle can be arranged on or fastened to the axle receptacle section arranged between the suspension section and the support section, and to a hollow cylindrical element (4, 6, 14), wherein the longitudinal member is formed from a cast or composite material and the hollow cylindrical element is formed from a weldable material, and wherein the hollow cylindrical element is arranged in the axle receptacle section and is connected to the longitudinal member in a form-fitting and/or force-fitting manner.