Motor-Driven Brake Plunger Assembly for Wheel Lock-Up Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vehicle braking systems face challenges in maintaining precise control, especially under adverse conditions, leading to wheel lock-up and reduced stability, and require efficient transition between different braking modes like regenerative and hydraulic braking.
Innovation Solution
A plunger assembly with a reversible motor, ball screw mechanism, and anti-rotation member that provides controlled brake fluid pressure to wheel brakes, incorporating an elastomeric tubular torque coupler and clamped connections for enhanced stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a driver applies excessive braking pressure under adverse conditions, then braking force is increased, but wheel lock-up occurs resulting in excessive slippage and loss of directional control
Solution Approach 1:
The ABS system continuously monitors wheel rotational behavior and uses this feedback to selectively apply and relieve brake pressure, maintaining wheel speed within an optimal slip range. The system detects wheel deceleration rates and adjusts braking force in real-time to prevent lock-up while maximizing braking effectiveness.
Solution Approach 2:
The brake system dynamically adjusts braking pressure between front and rear axles based on real-time wheel speed measurements. The electronically controlled ABS valves modulate pressure in each wheel brake independently, allowing the system to adapt to changing road conditions and maintain optimal slip levels at each axle.
2Productivity
If ABS valves are used to separately control braking pressures on front and rear wheels to achieve maximum braking forces, then braking performance is improved, but system complexity increases
Solution Approach 1:
The electronically controlled ABS valves serve multiple functions: they control individual wheel brake pressure for ABS operation, enable dynamic rear proportioning for optimal front-rear brake balance, and support traction control and vehicle stability control functions. This multi-functionality justifies the system complexity by providing comprehensive vehicle control capabilities.
3Stability of the object's composition
If braking pressures greater than master cylinder pressure are required quickly for optimal vehicle stability control, then vehicle stability is improved, but response time becomes critical
Solution Approach 1:
The system maintains brake pressure above master cylinder pressure ready at all times through the ABS valve configuration, allowing immediate application of high braking pressure when stability control is required. The valves are positioned and pre-charged to enable rapid pressure delivery without waiting for master cylinder pressure buildup.
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 plunger assembly enables precise control of brake fluid pressure, reducing wheel lock-up and improving vehicle stability by allowing dynamic adjustment of braking forces and smooth transitions between braking modes, enhancing overall braking performance and safety.
Implementation Method 1
The linear actuator includes a ball screw mechanism having a screw and a nut, with one of the screw and the nut defining a rotatable component connected to the motor rotor, and the other one of the screw and the nut defining a translatable component
Implementation Method 2
an elastomeric tubular torque coupler is provided for supporting the anti-rotation member relative to the housing for limited rotational movement
Implementation Method 3
The plunger head cooperates with the cylinder to define a first chamber containing brake fluid received from a fluid reservoir, and the first chamber is hydraulically connected to the wheel brakes via the first port
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an improved plunger assembly for a vehicle brake system. The plunger assembly is operable as a pressure source to control brake fluid pressure supplied to one or more wheel brakes. The plunger assembly comprises a housing defining a cylinder; a reversible motor supported by the housing and having a rotor; and a linear actuator such as a ball screw/nut mechanism driven by the motor. A plunger head is mounted in the cylinder and driven by the linear actuator in first and second opposite directions. Improvements include an elastomeric tubular torque coupler connected to a ball screw/nut anti-rotation member; and a clamped connection at an inner race of a motor bearing for securing the rotor to the ball screw/nut component.