Hydraulic Valve Spool for Independent Braking and Reactivity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current counterbalance valves with a single spool in hydraulic systems face challenges in controlling motor reactivity independently of braking softness, leading to complex and costly solutions, and cause pressure oscillations during motor stop, which can result in wear and oscillations of the vehicle or structure.
Innovation Solution
A valve with a spool that moves between three positions, utilizing a central chamber and compensation ducts to control fluid flow, with restrictors in control channels to adjust speed and prevent pressure drops, allowing for independent control of braking and motor stop, reducing pressure oscillations and improving precision in reaching the rest position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single spool counterbalance valve is used to control motor reactivity during braking and stop, then the control of negative loads is achieved, but the reactivity at start becomes dependent on braking softness and pressure oscillations occur during motor stop
Solution Approach 1:
The single spool valve is divided into two independent spools: a balancing spool for controlling negative loads and braking, and a reactivity spool for controlling motor start reactivity. This segmentation allows each spool to be optimized for its specific function, enabling independent control of reactivity and braking characteristics without interference between functions.
Solution Approach 2:
A make-up flow circuit is introduced as an intermediary mechanism that compensates for pressure drops during motor stop. The circuit includes a make-up flow valve and restrictors that regulate fluid flow to maintain stable pressure in the motor suction line, preventing pressure oscillations and improving control reliability.
2Ease of operation
If complex control of calibrated orifices is used to adjust spool movement in both directions, then reactivity at start can be made independent of braking softness, but the device complexity and cost increase
Solution Approach 1:
Instead of using complex calibrated orifices to control a single spool, the system segments control functions between two spools. The balancing spool handles braking control through simple orifices, while the reactivity spool handles start reactivity through dedicated control channels with restrictors, eliminating the need for complex bidirectional orifice control.
Solution Approach 2:
The valve design uses symmetric control channels and identical restrictors for both spools, creating a replicated structure that simplifies manufacturing and control. The control logic for each spool follows the same pattern, reducing the complexity of calibration and adjustment procedures.
3Speed
If the spool moves rapidly to control motor start reactivity, then reactivity is improved, but pressure drops occur during motor stop causing wear and oscillations
Solution Approach 1:
The valve separates the functions of rapid spool movement for reactivity control from pressure stabilization during stop. The reactivity spool enables fast response at start, while the balancing spool and make-up flow circuit work together to prevent pressure drops during motor stop, eliminating the harmful effects associated with rapid spool movement.
Solution Approach 2:
The make-up flow circuit acts as a cushioning mechanism that anticipates and compensates for pressure drops before they occur during motor stop. The restrictors and make-up flow valve pre-regulate the fluid flow to maintain stable pressure, preventing the harmful effects of pressure oscillations and wear.
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 solution provides effective control of braking and stop actions without pressure reduction, reduces oscillations, and enhances vehicle performance by allowing precise spool positioning and independent control of braking intensity and duration, while maintaining volumetric efficiency.
Implementation Method 1
a first elastic means (7) exerting a reaction force between the first closing cap (5) fastened to the body (2) and the first end (18) of the spool (4), said reaction force opposing to the displacement movement of the spool (4) that causes the penetration of the spool (4) with the first end (18) into the first chamber (20)
Implementation Method 2
The body (2) is provided with a first control channel (11) for the passage of a fluid between the outside of the valve (1) and the second chamber (21) and with a second control channel (12) for the passage of a fluid between the outside of the valve (1) and the first chamber (20)
Data Source
AI summary
Valve with a spool for the control of the start and of the stop of a hydraulic motor (17) in which an oblong spool (4) is mobile within an oblong seat (3) obtained in a body, the movement of the spool being controllable in two opposite directions of movement by means of control means, the spool being housed within an intermediate portion (22) of the seat in which said intermediate portion has a section size essentially equal to the section size of the spool, the spool being equipped with at least one intermediate portion with respect to a first end (18) and to a second end (19) with a section size smaller than the section size of the intermediate portion of the seat giving rise to the formation of an interstice (16) intended for the reciprocal connection of at least one first duct (9) and a second duct (10), the movement of the spool occurring between a first displacement position of the spool in a first direction in a condition of non-connection between the first duct and second duct, a second displacement position of the spool in a second direction opposite to the first direction in a condition of non-connection between the first duct and second duct, a third essentially central position of the spool within said intermediate portion of the seat in which the interstice is in a condition of connection between the first duct and second duct.