Dual-Circuit Service Brake with Force Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulically releasable spring-loaded brakes in mobile working machines, such as industrial trucks, lack force feedback for the driver, leading to potential overbraking and increased maintenance complexity, especially in dual-circuit service brake systems.
Innovation Solution
A dual-circuit service brake system is designed with a muscle-powered brake circuit and a power brake circuit, featuring a proportional pressure control valve that provides metered brake release pressure reduction, allowing for force feedback and reduced construction complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single-circuit spring-applied brake is used as a service brake, then the brake can be actuated into the release position by brake release pressure, but the driver receives no feedback at the brake pedal indicating when the brakes are applied
Solution Approach 1:
The brake system is divided into two independent brake circuits: a first brake circuit that provides force feedback to the driver for precise brake control, and a second brake circuit that provides the spring-applied brake function. This segmentation allows each circuit to perform its specific function without interfering with the other, resolving the contradiction between providing feedback and maintaining system simplicity.
Solution Approach 2:
The first brake circuit acts as an intermediary that transmits force feedback from the brake application state back to the driver through the brake pedal. This intermediary mechanism allows the driver to sense brake engagement without requiring complex modifications to the spring-applied brake mechanism itself.
2Reliability
If a dual-circuit service brake system is implemented, then braking reliability is improved, but construction complexity and costs increase
Solution Approach 1:
The dual-circuit system is segmented into a first brake circuit for service braking with force feedback and a second brake circuit for spring-applied braking. Each circuit is designed to be functionally independent, allowing the system to maintain high reliability while keeping individual circuit complexities manageable. The segmentation enables redundant braking paths without requiring a completely complex integrated system.
3Ease of operation
If cable-actuated brakes are used, then mechanical manual actuation is achieved, but the cable stretches resulting in significant tolerances and overbraking
Solution Approach 1:
The patent replaces the mechanical cable actuation system with a hydraulic brake circuit that uses fluid pressure transmission. This substitution eliminates the cable stretching problem inherent in mechanical systems, providing more precise and consistent brake torque control while maintaining mechanical manual actuation capability through the brake pedal.
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 system enables controlled braking with force feedback to the driver, reducing the risk of overbraking and maintaining low construction costs while ensuring reliable operation as a service brake with an auxiliary braking function.
Implementation Method 1
the spring-applied brake can be acted upon by means of a hydraulic brake release pressure present in a brake release pressure chamber in the direction of a release position and can be acted upon by means of a hydraulic brake pressure present in a brake pressure chamber in the direction of a braking position
Implementation Method 2
the spring-applied brake can be acted upon by means of a hydraulic brake release pressure present in a brake release pressure chamber in the direction of a release position
Implementation Method 3
the spring-applied brake can be acted upon by means of a hydraulic brake pressure present in a brake pressure chamber in the direction of a braking position
Implementation Method 4
a stack of several disc-like discs alternates between a stationary disc and a rotating disc. During braking, this stack is compressed at the ends by the stationary discs, and a shaft connected to the rotating discs is braked across the entire frictional surface
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a mobile work machine (1), in particular a forklift truck, with a braking device (6) designed as a hydraulically releasable spring-applied brake (7) and as a dual-circuit service brake, wherein the spring-applied brake (7) can be actuated towards a release position by means of a hydraulic brake release pressure present in a brake release pressure chamber (12) and can be actuated towards a braking position by means of a hydraulic brake pressure present in a brake pressure chamber (13). According to the invention, a first brake circuit (15) of the service brake is formed by a manual-operated brake (20) which has a manually actuated brake cylinder (21) by means of which the brake pressure present in the brake pressure chamber (13) can be generated by manual actuation.A second brake circuit (16) of the service brake is formed by an external force brake which has a pressure regulating valve (25) by means of which the brake release pressure present in the brake release pressure chamber (12) can be metered to decrease.