Hydrostatic Motor Braking Torque Isolation
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Solution Overview
Problem
Hydrostatic drive systems in vehicles, such as diggers and wheeled loaders, apply torque to the drive axles during braking processes, which is undesirable for optimal braking performance, as it interferes with the braking moment generated by the service brake.
Innovation Solution
A method that adjusts the hydro-motor to a minimum angle of rotation during braking, ensuring the output shaft is at zero torque, thus isolating the vehicle from additional torque influences, and returns to normal operation after the braking process is completed, ensuring optimal braking conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydro-motor maintains normal operating angle during braking, then the drive system continues to provide torque, but this additional torque interferes with optimal braking performance
Solution Approach 1:
The hydro-motor's angle of rotation is dynamically adjusted during braking based on detected braking situations. The control device reduces the absorption volume of the hydro-motor by adjusting its angle to a minimum value, allowing the system to transition from a static operating state to a dynamic braking state where torque is minimized. This resolves the contradiction by making the drive torque adaptive rather than fixed.
Solution Approach 2:
The patent changes the operating parameters of the hydro-motor during braking by adjusting the angle of rotation to a minimum value. This parameter change reduces the absorption volume and consequently minimizes the torque output during braking situations, allowing the service brake to work optimally without interference from drive torque.
2Reliability
If the hydro-motor is adjusted to minimum angle of rotation during braking, then zero torque is achieved on drive axles, but this requires additional control complexity
Solution Approach 1:
The control device performs multiple functions: it normally controls the hydrostatic gearbox operation and simultaneously detects braking situations to trigger the minimum angle adjustment. By making the control device multi-functional, the patent avoids adding separate dedicated braking control hardware, thus resolving the contradiction between achieving zero torque and maintaining control system simplicity.
Solution Approach 2:
The control device uses its existing sensing and control capabilities to automatically detect braking situations and adjust the hydro-motor angle accordingly. The system serves itself by utilizing the same control infrastructure for both normal operation and braking optimization, eliminating the need for additional complex control mechanisms.
3Reliability
If the hydro-motor operates at minimum absorption volume during braking, then optimal braking conditions are created, but the transmission range is limited
Solution Approach 1:
The hydro-motor operates at minimum absorption volume only periodically during detected braking situations, rather than continuously. The control device detects when braking is needed, adjusts the angle accordingly, and then returns to normal operation after braking. This periodic application of the minimum angle setting maintains transmission versatility while achieving optimal braking performance when required.
Solution Approach 2:
The control device detects braking situations in advance and proactively adjusts the hydro-motor angle to the minimum value before the braking process fully engages. This preliminary action ensures that the drive system is already in the optimal zero-torque state when braking begins, maintaining both braking performance and transmission adaptability.
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 effective braking without additional torque interference, enhancing the braking performance by ensuring only the service brake's moment acts on the wheels, and maintaining efficient transmission control post-braking.
Implementation Method 1
a hydrostatic pump, which is connected via operating lines to at least one hydro-motor, is driven by a drive motor designed as a diesel engine. By adjusting the angle of rotation of the hydro-pump or the hydro-motor, the transmission of a hydrostatic gearbox of this kind can be varied
Data Source
AI summary
The invention relates to a method for braking a vehicle, driven by means of a hydrostatic gearbox (28) and a hydrostatic drive. The hydrostatic gearbox (28) comprises at least one adjustable hydrostatic motor (6,6). The vehicle driven by means of the hydrostatic gearbox (28) may be retarded by an operating brake. On recognition of a certain braking process, the hydraulic motor (6,6) is adjusted to a minimal pivot angle. On recognition of a termination of the certain braking process, the hydraulic motor (6,6) is adjusted to a pivot angle which matches the speed achieved after the braking process.