Dual-Path Hydrostatic Drive Steering Control Mechanism
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Solution Overview
Problem
Existing steering and ground speed control mechanisms for vehicles with dual-path hydrostatic transmissions are either complex or costly, particularly due to the use of timing belts or four-bar linkages, necessitating a simpler and more cost-effective solution.
Innovation Solution
A control mechanism utilizing a gear train with a steering wheel connected through an intermediate idler gear to a steering output gear, mounted on a support arm that oscillates for steering and translates for speed/direction changes, simplifying the transfer of inputs to the hydrostatic transmission pumps via control rods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a timing belt drive with two belt sprockets is used for steering and ground speed control, then independent control of steering and ground speed is achieved, but the cost and complexity of the mechanism increase
Solution Approach 1:
The patent removes the timing belt drive system (sprockets, belts, and associated components) from the control mechanism. Instead, it uses a direct mechanical linkage system where the control plate is directly connected to the pump control arms through rods, eliminating the intermediate belt transmission components while maintaining the independent control capability.
Solution Approach 2:
The control plate serves multiple functions: it controls both steering (by oscillating about a vertical axis) and ground speed (by translating horizontally). This multi-functional component replaces the separate sprocket system, reducing overall mechanism complexity while maintaining independent control of both functions.
2Device complexity
If a four-bar linkage arrangement is used to replace the timing belt drive, then the cost and complexity are reduced, but the mechanism remains rather complex
Solution Approach 1:
The patent eliminates the four-bar linkage system entirely and replaces it with a simpler direct mechanical connection. The control plate is directly linked to the pump control arms through rods, removing the intermediate four-bar linkage components and simplifying the manufacturing process.
Solution Approach 2:
Instead of using a complex linkage system to transmit motion from a separate control input to the pumps, the patent inverts the approach by having the control plate itself directly connected to the pump control arms. This direct connection approach simplifies the mechanism while achieving the same control functions.
3Device complexity
If a gear train with support arm oscillation is used for steering control, then a compact simplified mechanism is achieved, but the mechanism must handle both steering and speed control functions
Solution Approach 1:
The control plate and support arm assembly serves dual functions: oscillating about the vertical axis for steering control and translating horizontally for ground speed control. This multi-functional design allows a single mechanical assembly to handle both steering and speed control, reducing overall system complexity.
Solution Approach 2:
The support arm is designed to perform two types of motion: oscillation (rotational movement) for steering and translation (linear movement) for speed control. This dynamic capability allows the same mechanical component to adapt to different control functions based on the operator's input, simplifying the overall mechanism.
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 solution provides a compact, simplified mechanism for controlling steering and ground speed, reducing complexity and cost while maintaining effective operation of the dual-path hydrostatic transmission system.
Implementation Method 1
a gear train that is carried by a support arm mounted for swinging about the first axis, with the output gear being mounted for rotating about the first axis
Data Source
AI summary
A dual-path hydrostatic drive arrangement for driving ground wheels at the opposite sides of the front of a self-propelled windrower is controlled for effecting steering and ground speed changes by a control mechanism including a gear train defined by a steering input gear and idler gear and steering output gears carried by a gear support member mounted for pivoting about a fixed axis of rotation of the input gear. The output gear is coupled for transmitting movement to first and second pump displacement control rods and steering is effected by turning a steering wheel which is coupled for rotating the input gear so as to impart rotation to the output gear which rotates so as to cause the control rods to move different amounts or in different directions. Speed changes are effected by a speed control device that is coupled for selectively swinging the speed/direction control arm.