Electromechanical Brake Servo with Resilient Compensation
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Solution Overview
Problem
Existing electromechanically actuated vehicle service brakes face issues such as complex production due to oriented thread requirements, precise radial stop adjustments, noise generation at thread stops, and incompatibility with vehicles already equipped with hydraulic brake circuits.
Innovation Solution
An electromechanically actuated vehicle service brake system that includes a pressure piston within a servo brake housing, allowing for electromechanical actuation to apply hydraulic pressure, and an axially resilient compensating element to reduce stress and noise, while maintaining tight length tolerances without an oriented thread, enabling compatibility with existing hydraulic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an oriented thread is used between the threaded spindle and threaded nut to maintain precise length tolerances, then the radial stop adjustment precision is improved, but the production complexity increases significantly
Solution Approach 1:
The patent changes the thread orientation parameter from fixed/oriented to non-oriented. The threaded spindle and threaded nut are designed with non-oriented threads, allowing the threaded nut to be rotated freely during assembly. This parameter change eliminates the complex oriented thread rolling process while maintaining precise length tolerances through the compensating element that absorbs dimensional variations.
2Reliability
If a radial stop disk is precisely adjusted during assembly to prevent jamming, then the reliability of the threaded spindle and threaded nut is improved, but the assembly complexity increases
Solution Approach 1:
The patent introduces a compensating element that is axially resilient, allowing the system to dynamically adapt to dimensional variations. The compensating element can deform axially to accommodate tolerance variations in the non-oriented thread engagement, maintaining reliable jamming prevention without requiring precise static adjustment of the radial stop disk during assembly.
3Measurement precision
If a hard stop is used between the threaded spindle and threaded nut to prevent over-travel, then the positioning accuracy is improved, but noise generation increases
Solution Approach 1:
The patent applies beforehand cushioning by introducing an axially resilient compensating element between the threaded spindle and threaded nut. This compensating element acts as a cushion that absorbs the impact when the stop is reached, preventing the hard collision that generates noise while still maintaining accurate positioning. The resilient element deforms to provide a soft stop rather than a hard impact.
4Device complexity
If an electromechanical actuator is used to actuate the brake directly, then the hydraulic circuit is eliminated, but compatibility with existing hydraulic brake systems is lost
Solution Approach 1:
The patent designs the electromechanical brake system with multi-functionality to achieve universality. The system can operate in two modes: (1) purely electromechanical operation where the actuator directly actuates the brake through the threaded spindle and compensating element mechanism, and (2) hybrid operation where the electromechanical actuator provides assistance to the hydraulic brake system. This dual-mode capability allows the same system to be installed in vehicles with or without existing hydraulic brake circuits.
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 allows for a quieter, more efficient braking system that can be integrated into vehicles with existing hydraulic brake circuits, reducing production complexity and maintaining precise length tolerances without the need for oriented threads, thus enhancing the braking function and system compatibility.
Implementation Method 1
the mechanical means additionally comprise a compensating element which is assigned to the projection and is axially resilient
Implementation Method 2
a rolling element thread gear mechanism has a threaded spindle and a threaded nut, which are in contact via a plurality of rolling elements
Implementation Method 3
the pressure piston can be actuated electromechanically via the transmission to carry out increased service braking, in turn to apply pressure to hydraulic pressure medium in the operating pressure chamber
Data Source
Figure 1~3b
Figure 4a~6c
Figure 6d~8b
AI summary
The invention relates to an electro-mechanically actuatable vehicle service brake (8). A rolling body threaded drive (10), which changes a rotational movement of an actuator (22) into a translatory movement, is drivingly connected to a pressure piston (18). Said pressure piston defines a working pressure chamber (20) which is connected via a hydraulic circuit (23) to wheel brakes on wheels (19). A radial stop disc (27) is associated with a compensation element which dampens the impact of the radial stop disc (27) on the threaded nut (14) when returning the threaded spindle. The compensating element also makes an oriented threaded roller unnecessary when producing the threaded spindle (12) and the threaded nut (14).