Electric Brake Piston Positioning for Consistent Brake Onset
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Solution Overview
Problem
The electric brake system experiences discomfort due to varying clearance amounts between braking members and the disc, leading to inconsistent timing in braking force generation, affecting driver comfort.
Innovation Solution
An electric brake system with a control device that maintains a predetermined clearance position between braking members and the disc, ensuring a consistent period from braking request to the initiation of braking force application, regardless of the piston's position at the time of the request.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clearance amount between braking members and disc varies, then the brake system can maintain drag-free operation, but the timing of braking force generation becomes inconsistent
Solution Approach 1:
The control device performs preliminary action by moving the piston to a predetermined clearance position during non-braking states, ensuring the braking members are properly positioned before braking is requested. This preliminary positioning eliminates variability in clearance amounts and ensures consistent braking force generation timing when braking is subsequently requested.
Solution Approach 2:
The control device uses feedback by continuously monitoring the piston position and clearance amount, then adjusting the piston position to maintain the predetermined clearance. This closed-loop control ensures that regardless of initial clearance variations, the system returns to the optimal clearance position, guaranteeing both drag-free operation and consistent braking timing.
2Device complexity
If the piston position is not controlled, then the brake structure remains simple, but the period from braking request to braking force application varies
Solution Approach 1:
The control device performs self-service by automatically adjusting the piston position based on detected clearance amounts. The system monitors its own state and makes necessary adjustments without external intervention, maintaining consistent braking timing while avoiding the need for complex mechanical positioning mechanisms.
Solution Approach 2:
The control device changes the parameter of piston position dynamically based on the detected clearance amount. By adjusting this key parameter, the system ensures that the period from braking request to braking force application remains constant, achieving consistent performance without complicating the overall brake structure.
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 solution ensures consistent braking force generation timing, reducing driver discomfort by maintaining a predetermined period from braking request to force application, even with changing clearance amounts.
Implementation Method 1
a thrust force generated through drive of an electric motor (39)
Data Source
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AI summary
Provided is an electric brake including: a brake mechanism configured to transmit, based on a braking request, a thrust force generated through drive of an electric motor to a piston configured to move brake pads to be pressed against a disc rotor; and an ECU for rear electric brake configured to control the drive of the electric motor, and to move, in a non-braking state, the piston to a predetermined clearance position at which a clearance between each of the brake pads and the disc rotor is a predetermined amount. The ECU for rear electric brake is configured to drive the electric motor so that a period from generation of the braking request to a start of the pressing of the disc rotor by the brake pads is a predetermined period regardless of a position of the piston at a time when the braking request is generated.