Crawler Work Machine Steering Control for Power Loss Reduction
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Solution Overview
Problem
Crawler-type work machines experience power loss during slow turning due to the use of braking force, which inefficiencies the engine and reduces performance.
Innovation Solution
The implementation of left and right planetary gear mechanisms, steering clutches, steering brakes, a turning motor, and a controller that control the engagement and braking of these components to create a rotation speed difference between output shafts, allowing for efficient slow turning without engine power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If steering brakes are used to perform slow turning, then turning control is achieved, but engine power loss increases
Solution Approach 1:
The patent segments the turning control function into two distinct modes: slow turning mode (using steering clutches and turning motor) and quick turning mode (using steering brakes). This segmentation allows the system to select the appropriate mechanism based on turning speed requirements, avoiding unnecessary engine power loss during slow turning operations.
Solution Approach 2:
The patent implements dynamic switching between different turning control mechanisms based on operating conditions. The controller dynamically adjusts which mechanism (steering clutches with turning motor or steering brakes) is active, allowing the system to optimize power consumption by using the turning motor for slow turning and brakes for quick turning.
2Loss of energy
If steering clutches and turning motor are used for slow turning, then engine power loss is suppressed, but device complexity increases
Solution Approach 1:
The steering clutches are designed with multi-functionality, serving both as power transmission components during straight movement and as control elements during turning operations. The turning motor integrates with the existing planetary gear mechanisms, allowing a single component to perform multiple functions and reducing the need for separate dedicated components.
Solution Approach 2:
The patent merges the turning control function with the existing power transmission system by integrating the turning motor with the planetary gear mechanisms. This consolidation allows the turning motor to work in conjunction with the steering clutches and existing transmission components, reducing overall system complexity compared to having completely separate turning mechanisms.
Data Source
AI summary
A bulldozer causes left and right steering clutches to engage and left and right steering brakes to release when an operating amount of a steering lever is greater than a first predetermined amount and less than a second predetermined amount, and drives a turning motor so that the rotation speed of an inside output shaft becomes lower than the rotation speed of an outside output shaft as the operating amount of the steering lever increases. A controller causes the engagement rate of an inside steering clutch to decrease and causes an inside steering brake to brake when the operating amount of the steering lever is equal to or greater than the second predetermined amount.