Asymmetrical Rivet Drive Unit Torque Transmission
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Solution Overview
Problem
Existing drive units for rivet setting devices are either too large and cumbersome or lack the necessary compactness and cooling efficiency, particularly when used in confined spaces and high-cycle applications like the motor vehicle industry, where high axial forces and thermal loads are prevalent.
Innovation Solution
A compact drive unit design featuring an electric direct drive with an asymmetrical torque transmission system, where the main part of the torque is absorbed on the machine side, allowing for a thin-walled, lightweight housing on the component side, and internal cooling channels for efficient heat dissipation using gas/air flow through the drive housing's interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the drive unit is designed to generate high axial forces (>50 kN) for secure rivet setting, then the setting force is improved, but the drive unit becomes large and robust, increasing radial dimensions
Solution Approach 1:
The drive housing is designed with asymmetrical torque transmission where the main part and guide part have different wall thicknesses and structural characteristics. The machine side has thicker walls to absorb high torque, while the component side has thinner walls to reduce radial dimension. This asymmetrical design allows the drive unit to generate high axial forces while minimizing the radial footprint on the component side.
Solution Approach 2:
The patent redistributes torque transmission across different spatial dimensions by concentrating the main torque absorption in the machine side (rear portion) and minimizing structural requirements on the component side (front portion). This dimensional redistribution allows high force generation without proportionally increasing radial dimensions in all directions.
2Area of stationary object
If the drive housing wall thickness is reduced to minimize radial dimension on the component side, then the radial dimension is improved, but the structural strength and torque absorption capacity deteriorate
Solution Approach 1:
The drive housing exhibits local quality variations with different wall thicknesses and structural properties at different locations. The machine side features thicker walls and reinforced structures to absorb high torque, while the component side has thinner walls to minimize radial dimension. This localized differentiation of structural quality allows the housing to meet both strength requirements and compactness goals simultaneously.
3Area of stationary object
If the drive unit is made compact with reduced radial dimensions, then the installation space requirement is improved, but the cooling efficiency deteriorates due to limited space for cooling channels
Solution Approach 1:
The cooling channels are arranged in the axial direction and utilize the available length of the drive housing rather than relying solely on radial space. The machine side cooling channels are positioned to maximize heat dissipation while maintaining compact radial dimensions. This spatial optimization allows efficient cooling in a compact design.
4Area of stationary object
If the drive unit is designed with compact dimensions for confined spaces, then the installation space is improved, but the weight increases due to robust construction requirements
Solution Approach 1:
The drive housing employs asymmetrical design with different wall thicknesses and structural reinforcements concentrated on the machine side where torque absorption is critical. The component side has minimized structural mass to reduce overall weight. This asymmetrical mass distribution achieves compact dimensions while minimizing weight by placing structural material only where mechanically necessary.
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
The solution enables a highly compact and efficient drive unit capable of generating high axial forces (>50 kN) while maintaining a small radial expansion, effectively managing thermal loads and ensuring reliable cooling, even in compact designs.
Implementation Method 1
internal cooling channels for efficient heat dissipation using gas/air flow through the drive housing's interior
Data Source
Figure 1~3
Figure 4
Figure 5~7
AI summary
The drive unit (4) is particularly designed for a (stamping) rivet setting device and has an electric direct drive (40) which comprises motor components that concentrically surround a control element (62) which can be linearly moved in the axial direction (8). In order to absorb the required torques while allowing a compact construction of the device, in particular in relation to a component side (12), a drive housing (10) has an asymmetrical design in a connecting region (21) between a main part (16) and a guide part (18) in which the control element (62) is guided, for the purpose of asymmetrical torque transmission. In addition or alternatively thereto, said highly compact construction achieves an efficient cooling by means of an inner cooling unit, in particular air flowing through a free inner space (76) in which the motor components are arranged.