Hydraulic Steering Fluid Controller With Stable Spool Rotation
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Solution Overview
Problem
The existing fluid controllers in hydraulic steering units exhibit unstable control behavior due to limited spool and sleeve rotation angles, leading to potential instability in fluid flow management.
Innovation Solution
The fluid controller design includes commutation grooves with closed bottoms and throughgoing openings as part of the valve geometry, allowing for increased spool rotation independence from commutation geometry partition angles, and varying flow resistance areas to enhance smooth operation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spool and sleeve are limited to small rotation angles (15° each direction) to match the commutation geometry partition, then the fluid flow control is simplified, but the control stability deteriorates due to insufficient rotation range
Solution Approach 1:
The invention separates the commutation geometry partition (6 sections) from the valve geometry partition (4 sections with throughgoing openings). This segmentation allows the spool to rotate independently beyond the limited 15° range without being constrained by the commutation groove partition, thereby improving control stability while maintaining manageable fluid flow control through the distinct valve geometry sections.
Solution Approach 2:
The invention introduces throughgoing openings in specific locations within the valve geometry, creating localized flow paths that are independent of the commutation geometry. This local quality enhancement allows certain regions to provide stable pressure distribution while other regions accommodate larger rotation angles, resolving the contradiction between rotation range and control stability.
2Reliability
If the spool rotation angle is increased beyond the commutation geometry partition limits, then the control stability improves, but the fluid flow management becomes more complex
Solution Approach 1:
By dividing the fluid control function into two independent geometric systems (commutation geometry for motor commutation and valve geometry for fluid flow control), the invention allows the spool to rotate through larger angles for improved stability while the valve geometry with its 4 sections manages fluid flow in a controlled manner, preventing excessive complexity.
Solution Approach 2:
The valve geometry with throughgoing openings acts as an intermediary between the spool rotation and the commutation geometry. It mediates the fluid flow management, allowing the spool to rotate freely for stability while the valve geometry sections regulate the fluid flow, thus preventing direct complexity transmission to the fluid management system.
3Ease of manufacture
If uniform partition angles are used for both commutation and valve geometries, then the manufacturing is simplified, but the pressure distribution becomes unbalanced causing spool and sleeve deformation
Solution Approach 1:
The invention applies different partition angles to different geometric systems: 6 sections for commutation geometry and 4 sections for valve geometry with throughgoing openings. This local differentiation optimizes pressure distribution balance in the valve geometry region while maintaining manufacturing feasibility through standardized geometric patterns in both systems.
Solution Approach 2:
By segmenting the geometric design into two independent systems with optimized partition angles, the invention allows each system to be manufactured with appropriate precision while achieving balanced pressure distribution overall. The commutation geometry can be manufactured with 6 equal sections while the valve geometry uses 4 sections optimized for pressure balance.
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 design reduces the risk of unstable control behavior by enabling larger rotation angles and balanced pressure distribution, resulting in improved steering smoothness and reduced risk of spool and sleeve deformation.
Implementation Method 1
the sleeve comprises a commutation geometry having a number of pairs of commutation grooves and controlling together with a housing geometry of the housing a flow of hydraulic fluid into and out of the working chambers and the spool comprises a spool geometry controlling together with a valve geometry of the sleeve a flow of hydraulic fluid between the supply port arrangement and the commutation geometry
Implementation Method 2
The fluid arriving at the measuring motor drives the measuring motor. The measuring motor is connected to the sleeve and restores the sleeve to an initial position once the necessary amount of fluid has been supplied to the steering motor
Data Source
AI summary
A fluid controller (1), in particular as part of a hydraulic steering unit, is described, said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a number of pairs of commutation grooves (12, 13) and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry controlling together with a valve geometry of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behaviour. To this end at least one of the commutation grooves (12, 13) comprise a closed bottom and at least one of the commutation grooves (12, 13) comprise a throughgoing opening (10, 11) forming part of the valve geometry.