Parking Brake Clamping Force Control via Resistance Measurement

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Solution Overview

Problem

Existing parking brake systems face challenges in accurately adjusting clamping force due to variations in electric motor power output caused by aging, temperature, and production variations, leading to inefficient and energy-intensive operation.

Innovation Solution

The method involves accurately determining the maximum generatable clamping force by the electric braking motor through measuring total resistance, including equivalent motor and control device resistances, and activating the additional hydraulic braking apparatus as needed to ensure precise and energy-efficient immobilization of the vehicle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the electric braking motor is dimensioned to provide maximum clamping force on steep slopes, then the vehicle can be immobilized on slopes of at least 20%, but the motor power output varies due to aging, temperature, and production variations, requiring supplementary hydraulic braking

Engineering Contradiction:

Improveclamping forceVSAvoidmotor power output consistency

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The control device continuously monitors the actual clamping force generated by the electric braking motor and compares it with the required clamping force. Based on this feedback, the control device determines whether supplementary clamping force from the hydraulic braking apparatus is needed, allowing dynamic adjustment to maintain reliable vehicle immobilization despite motor performance variations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the distribution of clamping force between the electric braking motor and the hydraulic braking apparatus. The control device modulates the contribution of each braking system based on real-time motor performance assessment, enabling the system to adapt to changing motor capabilities due to aging, temperature, or production variations

Inventive Principle:

Principle #15Dynamics

2Force

If the additional hydraulic braking apparatus is activated to compensate for reduced motor clamping force, then the required total clamping force can be achieved, but the time required to reach the total clamping force increases

Engineering Contradiction:

Improvetotal clamping forceVSAvoidtime to reach clamping force

Core Design Contradiction:

ForceVSLoss of time

Solution Approach 1:

The control device performs preliminary assessment of the electric braking motor's current capability before activating the hydraulic braking apparatus. By evaluating motor performance in advance and predicting the supplementary force needed, the system can activate the hydraulic apparatus at the optimal moment, minimizing the time delay while ensuring the total clamping force requirement is met

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the electric braking motor is dimensioned for maximum clamping force, then zero-energy immobilization on steep slopes is achieved, but energy consumption increases and component stress increases

Engineering Contradiction:

Improvevehicle immobilization capabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies partial action by having the electric braking motor provide only the portion of clamping force that is currently achievable, rather than continuously operating at maximum capacity. The hydraulic braking apparatus supplements only when necessary, reducing overall energy consumption while maintaining the capability for zero-energy immobilization on steep slopes

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control device dynamically changes the operating parameters of the braking system based on motor performance. By adjusting the distribution of clamping force between electric and hydraulic systems according to real-time motor capability, the system optimizes energy consumption while maintaining reliable vehicle immobilization

Inventive Principle:

Principle #35Parameter changes

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 quicker and more precise control of clamping force, reducing noise emissions and component stress, while optimizing energy usage by activating the additional braking apparatus only when necessary, thus compensating for variations in motor power output.

Implementation Method 1

Parking brakes having an electric motor, whose displacement motion acts via a gear drive, for example a spindle drive, directly on the brake pistons at the wheel brakes

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

on steeper slopes, a hydraulic braking apparatus is additionally actuated in order to elevate the clamping force to the value required to immobilize the vehicle

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentUS9321439B2Method, regulating and control appliance, and parking brake comprising such a regulating and control appliance, for adjusting a clamping force exerted by a parking brake

Publication Date: 2016.04.26 ROBERT BOSCH GMBH

AI summary

In a method for adjusting the clamping force exerted by a parking brake, which force is applied by an electric-motor braking apparatus that encompasses an electric braking motor and power-supply and control units, and as necessary by an additional braking apparatus, an equivalent resistance is ascertained from a measurement of current and voltage and is used as the basis for calculating the maximum generatable clamping force.