Electric Parking Brake Actuation for Mobile Work Devices
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Solution Overview
Problem
Existing parking brake systems for mobile working machines, particularly industrial trucks, face challenges in operational safety due to frequent manual operation requirements, potential driver negligence, and the need for hydraulic systems which are costly and prone to abrupt braking issues.
Innovation Solution
A control method using an electric actuator connected to a brake cable, where a controller detects specific braking conditions such as unoccupied driver's seat, lack of accelerator pedal operation, or emergency stop signals to automatically actuate the parking brake into the braking position, ensuring safety and comfort without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a spring-loaded brake with hydraulic control is used for automatic actuation, then automated parking brake function is achieved, but the system becomes complex and expensive with additional hydraulic components
Solution Approach 1:
The patent replaces the hydraulic release mechanism with an electric motor-driven threaded spindle drive. The electric actuator converts rotational motion into linear motion through the threaded spindle, directly actuating the brake cable without requiring hydraulic components. This substitution eliminates the complexity of hydraulic valves, fluid lines, and pressure control systems while achieving the same automatic actuation function.
Solution Approach 2:
The patent explicitly avoids using hydraulic or pneumatic systems for brake actuation. Instead, it employs an electric motor with a threaded spindle mechanism that converts electrical energy into mechanical linear force. This approach eliminates the need for hydraulic fluid, pumps, and control valves, significantly reducing system complexity and cost while maintaining automatic actuation capability.
2Object-affected harmful factors
If a spring-loaded brake is used with delayed application, then abrupt braking is avoided, but the braking force application is delayed and control is more difficult
Solution Approach 1:
The patent employs a dynamically controllable electric motor system that can adjust its actuation speed and force in real-time. The motor controller regulates the rotational speed of the threaded spindle, thereby controlling the rate at which braking force is applied. This dynamic control allows the system to gradually apply braking force without abrupt shocks, while also enabling rapid response when needed, eliminating the delay inherent in spring-loaded systems.
Solution Approach 2:
The patent changes the actuation parameters by using an electric motor with variable speed and torque control. Unlike spring-loaded brakes that have fixed force characteristics, the electric actuator can dynamically adjust its output force and application rate. The controller modifies electrical parameters (voltage, current, pulse width modulation duty cycle) to precisely control the braking force application, eliminating both abrupt braking and unnecessary delays.
3Ease of operation
If the parking brake is frequently manually actuated and released, then the driver can respond to operational needs, but operational safety is compromised due to potential driver negligence
Solution Approach 1:
The patent implements a self-service system where the parking brake automatically detects and responds to operational conditions without requiring driver intervention. Sensors monitor vehicle status (engine running, gear position, brake pedal activation) and the controller automatically actuates or releases the brake as needed. This eliminates the need for manual operation while ensuring consistent safety-critical functions are always performed correctly, preventing driver negligence.
Solution Approach 2:
The patent incorporates a feedback-controlled system with sensors that continuously monitor vehicle operating conditions. The occupancy sensor detects whether the driver is present, the gear position sensor monitors transmission state, and the brake pedal sensor detects service brake application. This feedback information is processed by the controller, which automatically actuates the parking brake when safety conditions require it, ensuring reliable operation independent of driver attention or memory.
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 solution enhances operational safety by preventing unintentional parking brake release, reduces driver workload, and provides cost-effective, controlled braking, eliminating the need for hydraulic systems and minimizing abrupt braking events.
Implementation Method 1
an electric actuator which is operatively connected to a transmission means, in particular a brake cable, for actuating the brake actuating force of the parking brake applies
Implementation Method 2
which, for example, drives a threaded spindle drive via a transmission device, to which a transmission means, for example a cable pull of a brake cable or a brake linkage, is attached for actuating the parking brake
Implementation Method 3
The threaded spindle drive is preferably designed to be self-locking so that the applied braking force is maintained when the electric motor is switched off and the parking brake thus remains in the released position or the braking position when the electric motor is switched off
Data Source
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AI summary
The control method involves determining signal of an allocation sensor of a driver place, particularly a driver seat that the driver place is not occupied, at the expiration of an allocation allowable time and determining a switching off signal of an entrance checking device, particularly a code switch or a code input device. The control is a function of signals on transmission or receipt units in surrounding of the mobile machine, particularly Radio frequency identificationtransponders, which brakes mobile machine with a steered braking force. An independent claim is also included for a mobile machine, particularly floor conveyance.