Pedal Simulator Friction Structure for Nonlinear Brake Feel
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Solution Overview
Problem
Conventional pedal simulators provide a linear reaction force, leading to inadequate pedal feeling and increased driver fatigue due to consistent resistance when pressing and releasing the pedal.
Innovation Solution
A pedal simulator with a friction member that is elastically deformable, providing a non-linear reaction force by expanding when moving forward and compressing when moving backward, and a groove design that increases resistance when the piston moves backward.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dry-bush with low frictional force is arranged in the piston reciprocation area, then noise is reduced and operability is improved, but the reaction force becomes linear and pedal feeling becomes inadequate
Solution Approach 1:
The patent applies local quality by using a dry-bush with low friction at the piston reciprocation area to reduce noise and improve operability, while simultaneously using a friction member with high friction at the piston outer surface area to provide non-linear reaction force and improve pedal feeling. This localized differentiation of friction characteristics resolves the contradiction between ease of operation and pedal feeling quality.
2Device complexity
If the reaction force increases linearly with pedal operation, then the structure is simple, but the driver experiences increased fatigue due to consistent resistance
Solution Approach 1:
The patent changes the friction parameter from low (dry-bush only) to high (friction member with coefficient of 0.3 or more) at the piston outer surface, transforming the reaction force characteristic from linear to non-linear. This parameter change provides varying resistance that reduces driver fatigue while maintaining structural simplicity.
3Ease of manufacture
If the friction member has high friction coefficient, then non-linear reaction force is achieved, but the friction member generates heat and wears out
Solution Approach 1:
The patent segments the friction characteristics into two distinct zones: a low-friction zone (dry-bush) at the piston reciprocation area for noise reduction and smooth operation, and a high-friction zone (friction member) at the piston outer surface for non-linear reaction force. This segmentation allows each zone to perform its specific function while mitigating the negative effects of high friction through the protective low-friction zone.
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
Enhances pedal feeling by offering a natural and stable operation, reducing driver fatigue through varying resistance forces based on pedal movement direction.
Implementation Method 1
a friction member that is arranged inside the housing and is elastically deformable, in contact with the outer surface of the piston to move forward when the piston moves forward and move backward when the piston moves backward
Implementation Method 2
the friction member is arranged to expand when moving forward and to be compressed when moving backward
Data Source
Figure 1
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AI summary
A pedal simulator (100) may include a housing (110); a piston (130), a front portion of which is arranged inside the housing and connected to a pedal (10) of a vehicle, and configured to be movable forward or backward in response to movement of the pedal; a reaction force member (140) arranged inside the housing and configured to be compressible by the forward movement of the piston and configured to provide a reaction force against the forward movement of the piston; and a friction member (150) movably disposed in the housing, configured to be elastically deformable such that the friction member is compressed when being moved in the backward direction and the friction member is expanded when being moved in the forward direction, and being in contact with the outer surface of the piston to apply friction to the movement of the piston and move in a same direction as the movement of piston.