Trailing Arm Axle Press Sleeve Eliminates Welding Stresses
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Solution Overview
Problem
Trailing arm axles for vehicle trailers face a disadvantage due to weakening of the oscillating shaft caused by residual welding stresses and unavoidable welding notches in the fastening area, which compromises the transmission of torques and lateral forces.
Innovation Solution
A press sleeve with a tapered through-opening is used to create an interference fit between the oscillating shaft and the compression sleeve, eliminating the need for weld seams in the critical area and ensuring effective torque and lateral force transmission through a non-positive connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rocker arm is welded to the rocker shaft to ensure rotationally fixed connection, then torque transmission is achieved, but the residual welding stresses and weld notches weaken the rocker shaft profile in the area of highest stress
Solution Approach 1:
The harmful welding process is extracted and removed from the critical connection area. Instead of welding the rocker arm directly to the rocker shaft, a press sleeve is introduced as an intermediary component that eliminates the need for welding in the high-stress area, thereby removing the source of welding stresses and notches while maintaining connection reliability through interference fit and positive connection mechanisms
Solution Approach 2:
A press sleeve is introduced as an intermediary component between the rocker arm and rocker shaft. This mediator enables torque and lateral force transmission through interference fit and positive connection (e.g., key-way or splines) without requiring welding in the critical area, thus protecting the rocker shaft from welding-induced weaknesses while maintaining rotational fixation
2Strength
If a press sleeve with tapered through-opening is used to create interference fit, then welding is eliminated in the critical area, but the assembly process becomes more complex
Solution Approach 1:
The press sleeve is pre-formed with a tapered through-opening that enables interference fit during assembly. The taper geometry is designed in advance to guide the press-fit installation process, allowing the sleeve to be pressed onto the rocker shaft in a controlled manner. This preliminary design of the tapered geometry simplifies the assembly process by providing self-alignment and progressive engagement, reducing the complexity despite eliminating welding
3Ease of operation
If the through-hole is designed with insertion section and main section, then easy positioning and damage prevention are achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The through-opening of the press sleeve is designed with different local geometries: an insertion section with larger diameter for easy positioning and alignment, and a main section with smaller diameter for creating the interference fit. This local differentiation of geometry allows the component to perform multiple functions (easy assembly and secure fixation) while the taper provides a gradual transition that accommodates reasonable manufacturing tolerances without requiring extreme precision
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 enhances the stability and strength of the oscillating shaft by avoiding welding stresses and notches, while maintaining efficient transmission of forces without the need for welds, thereby improving the overall performance of the trailing arm axle.
Implementation Method 1
a frictional connection is created through a press fit between the press sleeve and the vibratory shaft
Data Source
Figure 1~3
Figure 4~8
Figure 9~14
AI summary
A trailing arm axle for vehicle trailers comprises an axle tube (2), a swing shaft (3) with a coupling section (11), and a rocker arm (4). The rocker arm (4) is rotationally fixed to the swing shaft (3) by means of a press-fit sleeve (10, 10'). The press-fit sleeve (10, 10') has a through-opening (13) for the coupling section (11) that tapers towards the adjacent end of the swing shaft (3) and is press-fitted onto the coupling section (11).