Hydrostatic Road Machine Braking with ABS-Triggered Drive Disconnect
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Solution Overview
Problem
Hydrostatically driven road operating machines face issues with uniform braking of all wheels regardless of grip, hydraulic inertia causing delayed acceleration and braking, and the need for hydraulic ABS systems which are uncommon in heavy vehicles due to tuning difficulties.
Innovation Solution
A hydrostatically driven road operating machine with a mechanical braking system, a selection device for connecting or disconnecting wheels/axles, and a pneumatic ABS system independent of the driven apparatus, allowing dynamic modulation of braking based on individual wheel grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional hydraulic braking system is used on hydrostatically driven machines, then the braking system can be integrated with the existing hydraulic components, but all wheels are braked uniformly regardless of individual wheel grip conditions
Solution Approach 1:
The braking system is segmented to provide independent control for each wheel through individual calipers and brake discs. The electronic control unit enables separate modulation of braking force on each wheel based on its specific grip conditions, allowing differential braking while maintaining integration with the hydrostatic drive system's hydraulic components.
2Adaptability or versatility
If a hydraulic ABS system is installed to modulate wheel braking independently, then individual wheel grip can be optimized, but the system becomes difficult to tune and rigid due to high hydraulic pressures
Solution Approach 1:
The patent replaces the traditional hydraulic ABS modulation system with an electronic control system that acts on the mechanical brake components. The electronic control unit receives signals from wheel speed sensors and independently modulates each wheel's mechanical brakes through electronically controlled actuators, eliminating the need for complex hydraulic modulation while achieving the same ABS function with greater flexibility and easier tuning.
3Device complexity
If the hydrostatic transmission is used for both driving and braking functions, then system simplicity is maintained, but hydraulic inertia causes delayed acceleration and braking response
Solution Approach 1:
The patent merges the mechanical braking system with the hydrostatic transmission system, where the mechanical brakes and hydrostatic drive share common mechanical connections to the wheels and axles. This integration allows the mechanical brakes to provide immediate stopping force while the hydrostatic system simultaneously manages drive torque and recovers energy, combining the simplicity of unified system architecture with the rapid response of mechanical braking.
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
Enables effective modulation of braking and improved deceleration according to individual wheel grip, reducing interference and anomalies during operation.
Implementation Method 1
the drive is achieved by a hydrostatic transmission including at least one pump mechanically connected to an engine
Implementation Method 2
the hydrostatic system inherently presents a certain inertial effect (hydraulic inertia) on the downstream motion transmission
Implementation Method 3
a braking torque can be created, by reversing the flow in the hydraulic motor, between inlet and outlet, thereby dissipating the braking energy in the hydraulic system
Implementation Method 4
a mechanical braking system, a selection device for connecting or disconnecting wheels/axles
Data Source
AI summary
A hydrostatically driven road operating machine is provided comprising one or more wheels and/or one or more axles adapted to enable its movement over a ground; a hydrostatic driven apparatus operatively connected to one or more wheels and/or one or more axles to control their movement; a mechanical braking system including a pedal accessible by a user and configured to generate a braking intensity proportional to a braking pressure applied by the user on the pedal; a mechanical transmission including a selection device configured to determine at least one inertial connecting configuration wherein the mechanical transmission operatively connects the driven apparatus and one or more wheels and/or one or more axles, and a free configuration wherein the mechanical transmission operatively disconnects the driven apparatus selectively from one or more wheels and/or one or more axles; control means comprising rotation sensors operatively connected to one or more wheels and configured to acquire a respective rotational speed; an ABS system configured to acquire a respective rotational speed of one or more wheels and to determine, when one or more wheels lock, a gradual reduction of braking intensity so as to prevent slipping; wherein the ABS system is independent of the driven apparatus, and the control means are configured to bring the selection device from the connecting configuration to the free configuration exclusively when the ABS system is in operation.