Electrohydraulic Servo Brake Piston Composite Steel Ring
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Solution Overview
Problem
Integrated hydraulic modules of electrohydraulic servo brakes face issues with piston deformation, surface fractures, wear, and lack of robustness against temperature and radial forces, leading to reliability concerns.
Innovation Solution
A piston assembly using an anodized aluminum cylindrical body with a steel outer ring, featuring notches and radial tabs for rotational blocking, provides a stable and form-locked assembly that enhances reliability and robustness without increasing space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a piston made from anodized aluminum with notches is used for rotational blocking, then the device complexity is reduced, but the reliability deteriorates due to surface fractures and wear
Solution Approach 1:
The invention uses a composite piston structure combining anodized aluminum cylindrical body with a steel outer ring. The aluminum body provides lightweight construction and corrosion resistance, while the steel ring provides high strength, wear resistance, and resistance to surface fractures. This composite structure resolves the contradiction by maintaining structural simplicity while dramatically improving reliability through material properties.
Solution Approach 2:
The piston is divided into two separate components: the anodized aluminum cylindrical body and the steel outer ring with notches. This segmentation allows each component to be optimized for its specific function - the aluminum body for structural integrity and the steel ring for rotational blocking and wear resistance - thereby improving overall reliability without significantly increasing device complexity.
2Ease of manufacture
If a piston with notches and grease coating is used for rotational blocking, then the ease of manufacture is improved, but the reliability deteriorates due to dependency on temperature and radial forces
Solution Approach 1:
The steel outer ring mounted on the aluminum piston body provides a structure that is robust against temperature variations and radial forces. The steel material's high strength and thermal stability compensate for the simplicity of the notched design, ensuring reliable rotational blocking under varying operating conditions while maintaining ease of manufacture through the modular assembly approach.
Solution Approach 2:
The steel outer ring is specifically positioned at the critical location where rotational blocking occurs (at the notches interacting with needles). This local application of high-strength material precisely where needed provides temperature and force robustness without requiring the entire piston to be made of steel, thus maintaining ease of manufacture.
3Weight of moving object
If an anodized aluminum piston is used to reduce weight, then the weight of moving object is reduced, but the strength deteriorates leading to surface fractures and wear
Solution Approach 1:
The piston combines anodized aluminum (low density, lightweight) with a steel outer ring (high strength). The aluminum body provides weight reduction while the steel ring provides the necessary strength to prevent surface fractures and wear. This composite approach successfully resolves the contradiction between weight reduction and strength maintenance.
Solution Approach 2:
The steel outer ring is applied locally at the critical regions where strength is most needed (at the notches and outer surface subject to wear), while the majority of the piston body remains lightweight aluminum. This localized reinforcement provides strength where required without significantly increasing the overall weight of the moving object.
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 offers a reliable and robust design for rotational blocking, preventing piston deformation and wear, while maintaining ease of assembly and ensuring the hydraulic module's functionality under various conditions.
Implementation Method 1
a recirculating ball screw that controls the translational movement of the piston by its rotational movement, a threaded core of the screw being fixedly connected to the piston
Implementation Method 2
the piston is a piece formed from a cylindrical body made from anodized aluminum
Implementation Method 3
The connection between the notches of the flange and the needles for rotational blocking is provided with a fine coat of grease to reduce the coefficient of friction
Data Source
AI summary
A hydraulic module including a cylinder (2) which accommodates a piston (3) which delimits a chamber (4) which receives the brake fluid. The piston (3) is connected to the electric motor (5) of the module (1) by a recirculating ball screw (6), whose core (61) is fixedly connected to the piston (3) which itself is guided by needles (21) which are parallel to the axis (xx) of the piston (3) and with which notches (351) on the circumference of the piston (3) interact. The piston (3) is a piece, which is formed from a cylindrical body (32) made from anodized aluminum and an outer ring (35) made from steel, which is forcibly mounted on the edge (34) of the piston and is provided with notches (351) with a cross section which corresponds to the effective cross section of the needles (21).