Radial Clutch Brake Layout for Stall Torque Test Benches
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Solution Overview
Problem
Existing powertrain test benches require manual conversion for stall torque tests and have limited air gaps that affect rotational measurements, leading to inefficiencies and vibrations.
Innovation Solution
A drive unit for a powertrain test bench featuring a frame, electric motor, coupling, and brake with a radial outer surface as the first friction partner and brake pads as the second friction partner, allowing for rotationally fixed connections and independent torque measurements without setup effort, while minimizing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a brake disc is arranged on the motor shaft or drive train with a brake caliper, then rotational locking is achieved, but axially required installation space increases and torsional stiffness decreases causing vibrations
Solution Approach 1:
The brake is redesigned from an axial configuration (brake disc on motor shaft) to a radial configuration (brake drum on output shaft). The brake drum is arranged radially outside the output shaft, utilizing the radial dimension instead of axial space, thereby reducing the axially required installation space while maintaining braking functionality.
Solution Approach 2:
The braking function is separated from the motor shaft assembly and placed on the output shaft assembly. This segmentation allows the brake components (brake drum, brake caliper) to be positioned in a location that does not interfere with the motor shaft's axial space requirements while still providing effective rotational locking.
2Force
If a brake disc is arranged on the motor shaft or drive train with a brake caliper, then rotational locking is achieved, but torsional stiffness decreases causing vibrations
Solution Approach 1:
By moving the brake from an axial arrangement on the motor shaft to a radial arrangement on the output shaft, the brake components are positioned in a dimension that does not compromise the torsional stiffness of the motor shaft and drive train. The radial placement allows the brake drum to be enclosed by the brake caliper without introducing torsional flexibility into the rotational path.
3Measurement precision
If the air gap between brake components is small for rotational measurements, then measurement precision is improved, but the brake cannot effectively lock rotation
Solution Approach 1:
The brake system is configured in the radial dimension rather than the axial dimension. The brake drum is arranged radially outside the output shaft with sufficient radial clearance to accommodate the brake caliper. This radial configuration provides adequate air gap for effective braking force while not interfering with the axial air gap requirements for rotational measurements.
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
Enables efficient stall torque testing and reliable rotational measurements by eliminating the need for manual conversion and reducing vibrations, ensuring accurate and efficient powertrain testing.
Implementation Method 1
a brake, the first friction partner of which is a radial outer surface of the coupling and the second friction partner of which is at least one brake pad
Data Source
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Figure 2
AI summary
The invention relates to a drive unit (10) for a drive train test bench for testing a motor vehicle drive train, comprising: a frame (20); an electric motor (30) having a motor shaft; a clutch (40); and a driven shaft (50), wherein: the electric motor (30) is positioned on the frame (20); the driven shaft (50) is rotatably held in a bearing of the frame (20); and the motor shaft is connected via the clutch (40) to the driven shaft for conjoint rotation. The drive unit (10) according to the invention is characterised in that the drive unit (10) also comprises a brake (60), the first friction partner (61) of which is a radial outer side (61) of the clutch (40) and the second friction partner (62, 63) of which is at least one brake pad (62, 63). The invention also relates to a corresponding drive train test bench.