Compact Electromechanical Brake Actuator With Hollow Spindle Sensing
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Solution Overview
Problem
Existing electromechanical wheel brakes face challenges with long construction length and installation complications due to the need for complex hydraulic systems and additional sensors, which are not suitable for compact spaces, especially in passenger cars.
Innovation Solution
An electromechanical brake device with a planetary gearbox and a hollow spindle that integrates a force sensor, allowing for a compact design and direct integration of sensors within the spindle, reducing installation length and enabling precise force detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a ball screw as rotational-translational movement converter is used, then wear compensation is simplified, but the construction length increases due to longer effective stroke requirements
Solution Approach 1:
The patent places the axial bearing inside the hollow spindle, creating a nested structure where the bearing is positioned within the spindle's internal cavity. This nesting allows the bearing to be integrated into the existing spindle structure without adding external length, thereby simplifying wear compensation while maintaining compact construction dimensions.
2Measurement precision
If force sensors are installed in series behind the rotational-translational movement converter, then force detection is enabled, but the installation length increases
Solution Approach 1:
The patent integrates the force sensor inside the hollow spindle structure, nesting it within the existing component rather than adding it as a separate external element. This allows force detection functionality to be incorporated without increasing the overall installation length of the brake device.
Solution Approach 2:
The patent combines the force sensor with the spindle structure, merging two previously separate components (spindle and force sensor) into a single integrated assembly. This consolidation eliminates the need for additional installation space while maintaining force detection capability.
3Length of moving object
If a planetary gearbox is integrated with a hollow spindle, then the axial installation length is reduced, but the structural complexity increases
Solution Approach 1:
The patent nests the axial bearing within the hollow spindle of the planetary gearbox, creating a compact integrated structure. This nesting approach reduces the axial installation length by utilizing the internal space of the spindle, while the modular planetary gearbox design helps manage the inherent structural complexity.
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 provides a compact electromechanical brake device with integrated sensors, achieving a short installation size and precise force detection, suitable for both front and rear axles of motor vehicles, while maintaining efficient brake operation.
Implementation Method 1
a force transmission unit, wherein the force transmission unit comprises a planetary gearbox with a sun gear, planet gears, a planet carrier and a ring gear
Implementation Method 2
provided in the cavity is an axial bearing, for example for absorbing axial forces occurring during brake application
Implementation Method 3
a ball screw as rotational-translational movement converter
Data Source
AI summary
An electromechanical brake device with a linear actuator for moving a brake piston in an electromechanically operable wheel brake of a motor vehicle, and to a motor vehicle having an electromechanical brake device of this type. The electromechanical brake device has an actuator unit wherein the actuator unit comprises a rotational-translational movement converter having a piston movable in an axial direction and a spindle wherein the spindle is hollow at least in portions, to at least partially define a cavity, a force transmission unit, which comprises a planetary gearbox with a sun gear, planet gears, a planet carrier and a ring gear, and an axial bearing located in the cavity for absorbing axial forces occurring during brake application. The electromechanical brake device herein can also comprise a force sensor.