Shift Assisted Braking for Hydrostatic Transmission Wear Reduction
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Solution Overview
Problem
The activation of brake mechanisms in power machines with hydrostatic drive assemblies at high speeds leads to significant impact and wear, as existing brake systems do not effectively manage the transition from high to low speeds to mitigate this issue.
Innovation Solution
A shift assisted brake control system that downshifts the hydrostatic transmission from high to low speed upon brake activation, followed by a pause and subsequent return to high speed, reducing the torque and wear on brake components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake mechanism is activated while the drive shaft or axle is rotating at high speeds, then the braking function is achieved, but significant impact or wear is imparted to the brake mechanism or components
Solution Approach 1:
The system performs a preliminary speed reduction by downshifting the hydrostatic transmission to a lower gear ratio before the brake mechanism is activated. This preliminary action reduces the rotational speed of the drive shaft or axle, so that when braking occurs, the impact and wear on brake components is significantly reduced while still achieving effective stopping.
Solution Approach 2:
The braking process is segmented into multiple phases: (1) detection of brake activation signal, (2) downshifting to reduce speed, (3) pausing at reduced speed, and (4) activating the brake mechanism. This segmentation allows the system to separate the speed reduction function from the braking function, protecting the brake mechanism from high-speed impact.
2Object-affected harmful factors
If the transmission is shifted to low speed before braking, then the impact on brake mechanism is reduced, but the braking time is extended due to the pause period
Solution Approach 1:
The system dynamically adjusts the transmission gear ratio in real-time based on the braking requirement. By shifting to a lower gear ratio temporarily during the braking process and then returning to the original gear ratio after braking is complete, the system optimizes both brake protection and overall operational efficiency, minimizing the time penalty while maximizing brake component protection.
Data Source
AI summary
A shift assisted brake control system for a power machine or vehicle is disclosed. In illustrated embodiments, the shift assisted brake control system employs a shift assisted brake sequence. In illustrated embodiments, the shift assisted brake sequence shifts an operating speed of a hydrostatic transmission or motor from a high speed to a low speed upon activation of a brake switch or device. This reduces impact or wear to the brake mechanism. In illustrated embodiments, the transmission or motor remains at the low speed for a pause period and following the pause period, the transmission or motor is shifted to the high speed.