Hydraulic Return to Neutral Mechanism
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Solution Overview
Problem
Existing hydraulic apparatuses face challenges in efficiently returning a trunnion arm to a neutral position due to unbalanced forces applied by single spring mechanisms, which can lead to increased friction, reduced accuracy, and limited flexibility in adapting to different space constraints.
Innovation Solution
A return to neutral mechanism utilizing two springs, positioned in an 'x' configuration, to apply balanced forces to a trunnion arm, allowing for the use of lower rate springs and enabling the mechanism to function with various types of springs (tension, compression, torsion, or leaf springs), reducing overall load and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spring mechanism is used to return the trunnion arm to neutral position, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate due to unbalanced forces and increased friction
Solution Approach 1:
The single spring mechanism is segmented into two separate springs (first spring and second spring) that independently apply forces to the trunnion arm. This segmentation allows each spring to be optimized for its specific direction of force application, resulting in balanced forces that improve neutral position accuracy while maintaining reasonable device complexity
Solution Approach 2:
The second spring acts as a counterbalance to the first spring, with both springs applying equal and opposite forces to the trunnion arm when it is in the neutral position. This counterbalancing arrangement eliminates unbalanced forces and friction that would otherwise degrade positioning accuracy
2Force
If high rate springs are used to ensure strong return force, then the force applied to return trunnion arm is improved, but the loss of energy increases due to higher friction and the device complexity increases
Solution Approach 1:
The two springs are configured to apply balanced forces that cancel each other out when the trunnion arm is in the neutral position. This balance eliminates excessive friction and energy loss that would occur with a single high-rate spring, while still providing sufficient return force through the combined action of both springs
Solution Approach 2:
The system changes the parameter of spring rate by using two lower rate springs instead of one high rate spring. The combined force of the two lower rate springs equals the force of a single high rate spring, but with reduced friction and energy loss
3Device complexity
If a single spring mechanism is used, then the device complexity is reduced, but the adaptability deteriorates due to limited flexibility in adapting to different space constraints
Solution Approach 1:
The segmented two-spring configuration allows each spring to be independently positioned and oriented to accommodate different space constraints. This segmentation provides flexibility in adapting the mechanism to various installation environments without significantly increasing overall device complexity
Solution Approach 2:
The two springs can be arranged in different spatial configurations (different dimensions and orientations) to adapt to various space constraints. This dimensional flexibility allows the mechanism to be adapted to different installation environments while maintaining a relatively simple overall structure
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
The dual-spring mechanism effectively biases the trunnion arm into a neutral position with reduced friction and increased accuracy, accommodating different space constraints and customer needs while providing a cost-effective solution.
Implementation Method 1
a first spring having a first end attached to a first end of the third bracket and a second end attached to a first end of the fourth bracket; a second spring having a first end attached to a second end of the third bracket and a second end attached to a second end of the fourth bracket; wherein the springs bias the first end of the third bracket and the first end of the fourth bracket toward the stop member of the second bracket and bias the first bracket toward a neutral position
Data Source
AI summary
A return to neutral mechanism is provided for hydraulic apparatuses such as motors/pumps that utilize a swashplate and a trunnion arm to control flow. The return to neutral mechanism includes two rotating brackets which have ends aligned to a single plane. Two springs are utilized and attached to the ends of the two rotating brackets giving the force mechanism the ability apply the force in a direct path, reducing friction, increasing life, and improving accuracy. This design is an “x” type mechanism, the force arms are in-line and do not cross, the force is applied equally on both sides of the fulcrum and therefore balanced. The mechanism can be can be used with compression springs, tension springs, torsion springs, or leaf springs.