Electric Motor Brake Actuator Cost Reduction via Segmented Rotor
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Solution Overview
Problem
The existing construction of electric-motor brake actuators for motor vehicles is costly due to the need for a fully functional motor installed in a neutral housing, which can be simplified to reduce equipment and cost outlay.
Innovation Solution
A separately produced rotor with a pre-assembled magnet assembly, comprising hollow cylindrical sintered magnets and a sheet metal flux guide with radial slits, is installed in a cup within the actuator housing, allowing for a more cost-effective and compact design by eliminating the need for a self-contained motor and using a vibration-damped bearing bridge for the rotor shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fully functional motor is installed in a neutral housing receiving device, then the motor can be securely mounted and function reliably, but the equipment outlay and construction costs increase
Solution Approach 1:
The motor is divided into separate components: the rotor assembly (with shaft, bearing, and commutator) is produced separately and installed into the actuator housing, while the stator magnet assembly is pre-installed in the housing. This segmentation eliminates the need for a complete pre-assembled motor unit in a neutral housing, reducing construction complexity while maintaining reliable mounting through dedicated component interfaces.
Solution Approach 2:
The motor components are merged directly into the actuator housing structure. The stator magnet assembly is integrated into the housing, and the rotor assembly is mounted within the same housing space, eliminating the separate neutral housing receiving device. This merging reduces the number of components and simplifies the overall construction while ensuring reliable mounting through direct integration.
2Ease of manufacture
If a self-contained motor with complete housing is used, then the motor is ready for immediate installation, but the overall cost and equipment outlay increase
Solution Approach 1:
The stator magnet assembly is pre-assembled and installed in the actuator housing before the rotor assembly is mounted. This preliminary action allows the housing to be prepared in advance with the stator components, so that when the rotor assembly (produced separately with its bearing and commutator) is installed, the motor is immediately complete and ready for operation, eliminating the need for a complete pre-housed motor unit.
Solution Approach 2:
The rotor assembly is extracted as a separate producible unit from the complete motor system. By taking out the rotor with its bearing and commutator as a standalone component that can be manufactured and prepared separately, the system allows for simplified production and installation while maintaining ease of assembly through the pre-prepared housing with stator magnets already in place.
3Device complexity
If conventional multi-stage gear mechanisms are used instead of belt drive, then the reduction gear can be achieved, but the construction becomes less compact and the motor axis cannot be arranged parallel to the transmission axis
Solution Approach 1:
The conventional multi-stage gear mechanism is replaced with a belt drive system. This substitution allows the motor axis to be arranged parallel to the transmission axis, achieving the required torque multiplication through the belt transmission ratio while maintaining a compact construction. The belt drive provides the necessary mechanical advantage without the bulk and complexity of multiple gear stages, enabling optimized axis arrangement for compactness.
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 reduces the overall cost and complexity of the brake actuator construction while maintaining functionality, enabling a compact and flexible design for motor vehicle applications.
Implementation Method 1
The hollow cylindrical sheet metal flux guide is provided with slits over at least a part of its axis-parallel length along a generating in order to be able to install said sheet metal flux guide in the cup more easily, namely with less resilient elastic radial compression, in that the sheet metal flux guide relaxes in such a manner that its diameter increases and as a consequence it is held radially on the inner peripheral surface of the cup in a non-positive manner
Implementation Method 2
A permanent magnetic magnet assembly (18) is installed in this cup (17) in a sleeve-shaped coaxial manner. Said assembly provides on the periphery, in the circumferential direction, a sequence of (at least two) alternating magnetic poles (19)
Implementation Method 3
using a vibration-damped bearing bridge for the rotor shaft
Data Source
AI summary
A particularly cost-effective electric-motor brake actuator which is useable in a highly flexible manner in respect of structural boundary conditions has an integrally formed cup which is equipped with a permanent magnet assembly and can be equipped with a separately manufactured, electromagnetic rotor assembly. In this manner, the equipment outlay is reduced as is the construction costs.