Disc Brake Vibration Estimation Using Contact Stiffness Fluctuation
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Solution Overview
Problem
Current methods fail to effectively estimate vibrations in the in-plane direction of disc brakes, which are a significant factor in brake squeal, and lack the capability to simulate both in-plane and out-of-plane vibrations simultaneously.
Innovation Solution
A disc brake vibration estimation method and device that obtain input physical parameters about the disc rotor and pad, estimate in-plane vibrations using a fluctuation in contact stiffness, and determine brake squeal through displacement analysis, employing equations such as [M]{{umlaut over (x)}}+([K]+[U]·cos ωt){x}=0, where [M] is the mass matrix, [K] is the stiffness matrix, [U] is the contact stiffness matrix, and ω is the pad's characteristic frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vibration estimation methods are used, then out-of-plane vibration can be estimated, but in-plane vibration cannot be estimated
Solution Approach 1:
The patent applies universality by creating a vibration estimation device that can handle both in-plane and out-of-plane vibration modes through a unified mathematical model. The equation of motion incorporates general stiffness matrices and contact force terms that are applicable to any vibration mode, making the system multi-functional rather than mode-specific.
Solution Approach 2:
The patent transitions from estimating only out-of-plane vibrations to including in-plane vibrations by adding dimensional completeness to the estimation model. The mathematical formulation explicitly includes in-plane displacement components and corresponding stiffness terms, thereby expanding the estimation capability into the previously missing in-plane dimension.
2Ease of manufacture
If vibration estimation model is simplified, then calculation is easier, but accuracy of brake squeal prediction deteriorates
Solution Approach 1:
The patent changes the parameters of the vibration model by incorporating mode-specific stiffness matrices and contact force parameters that accurately represent the physics of brake squeal. Rather than using a simplified generic model, the patent adjusts the mathematical parameters to include mode-dependent terms while maintaining computational tractability through efficient matrix formulations.
3Reliability
If both in-plane and out-of-plane vibrations are estimated, then brake squeal can be accurately predicted, but device complexity increases
Solution Approach 1:
The patent applies segmentation by separating the vibration estimation into distinct mode components (in-plane and out-of-plane) that can be calculated independently through modal analysis. The total vibration response is obtained by superimposing the results from separate mode-specific calculations, thereby managing complexity through systematic decomposition rather than attempting to solve all modes simultaneously in a monolithic model.
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 approach allows for accurate estimation of disc brake vibrations in the in-plane direction, enabling the determination of brake squeal and facilitating the design of disc brakes that reduce brake squeal by modeling both in-plane and out-of-plane vibrations.
Implementation Method 1
estimating a vibration of the disc brake in an in-plane direction which is a circumferential direction of the disc rotor according to at least the obtained input physical amounts and a fluctuation in contact stiffness between the disc rotor and the pad
Implementation Method 2
a vibration is caused by contact of the pad with the rotating disc rotor and results in resonance between the rotating disc rotor and the pad to cause brake squeal
Implementation Method 3
A disc brake generates braking torque by bringing a pad into contact with a rotating disc rotor
Data Source
AI summary
A disc brake vibration estimation method includes a step of obtaining input physical amounts that are physical amounts about the disc rotor and the pad, a step of estimating a vibration of the disc brake in an in-plane direction which is a circumferential direction of the disc rotor according to the obtained input physical amounts and a fluctuation in contact stiffness between the disc rotor and the pad, and a step of making a determination at least about squeal of the disc brake in the in-plane direction according to a displacement or a value derived from the displacement after a prescribed period from a start of estimation after the vibration of the disc brake is estimated.