Multi-Stage Spindle-Nut Brake Actuator for Rapid Clamping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor vehicle brakes that combine hydraulic and electromechanical actuation suffer from long actuation times and complex structures, particularly when transitioning between service brake and parking brake modes, often requiring significant time to achieve the desired braking force.
Innovation Solution
A multi-stage spindle-nut arrangement with different thread pitches is used, where the first stage with a larger thread pitch facilitates rapid displacement during initial actuation and switches to a second stage with a smaller thread pitch to achieve the necessary clamping force, utilizing a weaker electric motor drive and a compression spring mechanism to manage axial forces and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single-stage spindle-nut arrangement with small thread pitch is used to achieve high clamping force, then the desired braking force is achieved, but the actuation time becomes excessively long
Solution Approach 1:
The spindle-nut arrangement is divided into two distinct stages: a first stage with a first spindle-nut pairing having a first thread pitch, and a second stage with a second spindle-nut pairing having a second thread pitch. This segmentation allows the system to optimize for different phases of operation - rapid displacement initially, then high clamping force subsequently - thereby resolving the contradiction between actuation speed and force generation.
Solution Approach 2:
The system dynamically switches between different thread pitches based on the actuation phase. During a first actuating phase, the first spindle-nut pairing with the first thread pitch is effective for rapid displacement. During a second actuating phase, the second spindle-nut pairing with the second thread pitch becomes effective for generating high clamping force. This dynamic adaptation resolves the time-force contradiction.
2Reliability
If a gear arrangement with self-locking worm gear is used to prevent parking brake release, then reliability is improved, but the actuation time and complexity increase
Solution Approach 1:
The braking function is segmented into service braking and parking brake functions. The service brake uses a conventional gear arrangement for rapid response, while the parking brake uses a multi-stage spindle-nut arrangement with self-locking capability. This segmentation allows each function to be optimized independently, resolving the contradiction between reliability and actuation time.
Solution Approach 2:
The system changes the mechanical parameter (thread pitch) of the spindle-nut arrangement between different actuation phases. The first spindle-nut pairing has a first thread pitch optimized for speed, while the second spindle-nut pairing has a second thread pitch optimized for force. This parameter change enables the system to achieve both rapid actuation and reliable holding without excessive time loss.
3Loss of time
If a multi-stage spindle-nut arrangement with different thread pitches is used, then actuation time is reduced and motor power is reduced, but the device complexity increases
Solution Approach 1:
The first and second spindle-nut pairings are integrated into a single multi-stage spindle-nut arrangement that can switch between different thread pitches. This merging of functions into one coordinated system achieves rapid actuation and reduced motor power requirements while managing complexity through integrated design rather than separate systems.
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 design significantly reduces the time to achieve the desired braking effect while using a less powerful motor drive, ensuring rapid displacement and strong clamping forces, and prevents unintentional release through self-locking mechanisms.
Implementation Method 1
a compression spring mechanism to manage axial forces and torque transmission
Implementation Method 2
prevents unintentional release through self-locking mechanisms
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The invention relates to a motor vehicle brake, in particular a motor vehicle brake that can be actuated in a combined hydraulic and electromechanical manner, having an actuator assembly (10) comprising: a housing (12), an actuating element (14) that can be displaced relative to the housing (12) along a longitudinal axis (A) for the hydraulic or electromechanical displacement of a brake lining, a motor drive (22), and a displacement mechanism, arranged between the motor drive (22) and the displaceable actuating element (14), for displacing the actuating element (14). In order to achieve a rapid feed movement, the displacement mechanism according to the invention has a multi-stage spindle-nut arrangement (31) comprising a first spindle-nut pair having a first thread pitch and a second spindle-nut pair having a second thread pitch, wherein the first thread pitch is greater than the second thread pitch, wherein, during an electromechanical actuation of the motor vehicle brake, the first spindle-nut pair is active in a first actuating phase and the second spindle-nut pair is active in a second actuating phase.