Hydraulic Steering Unit Variable Orifices Dead Band
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Solution Overview
Problem
Existing hydraulic steering units face challenges in efficiently steering vehicles, particularly in heavy environments where rear wheels require auxiliary force, and they often have a dead band issue that affects precision.
Innovation Solution
A hydraulic steering unit with a sophisticated port arrangement and orifice configuration, including variable orifices and a measuring motor, which connects flow paths to minimize dead band and allows for dual rear axis steering, enabling precise control of hydraulic fluid flow between front and rear steering motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional hydraulic steering unit is used, then the structure is simple, but it cannot provide auxiliary force to rear wheels in heavy environments
Solution Approach 1:
The hydraulic steering unit is segmented into multiple working port arrangements (first working port arrangement with ports L1, R1 and second working port arrangement with ports L2, R2), each capable of independently controlling different steering motors. This segmentation allows the system to provide auxiliary force to rear wheels while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The hydraulic steering unit is designed with multi-functionality to handle both conventional single-axle steering and dual rear axis steering applications. The port arrangement and flow path configuration enable the system to adapt to different steering configurations, providing universal applicability across various vehicle types and steering requirements.
2Measurement precision
If a conventional hydraulic steering unit is used, then the structure is simple, but it has dead band issues affecting precision
Solution Approach 1:
The hydraulic steering unit employs variable orifices (first left orifice, first right orifice, second left orifice, second right orifice) that can dynamically adjust flow characteristics based on steering conditions. This dynamic adjustment eliminates dead band issues by ensuring continuous, precise control of hydraulic fluid flow to the steering motors, thereby improving steering precision without requiring overly complex fixed-geometry components.
3Adaptability or versatility
If dual rear axis steering is implemented, then auxiliary force can be applied to rear wheels, but the connection between flow paths becomes complex
Solution Approach 1:
The hydraulic steering unit merges flow paths strategically to simplify connections. The first left working flow path and second left working flow path are connected, as are the first right working flow path and second right working flow path. This merging approach reduces the number of independent connections required while maintaining the ability to provide auxiliary force to rear wheels in dual rear axis steering configurations.
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 enables precise and efficient steering in heavy environments by minimizing the dead band and allowing auxiliary force application to rear wheels, improving steering precision and effectiveness.
Implementation Method 1
a variable first left orifice (A2L) connected to the main flow path (2) and to the first left working flow path (4), a variable first right orifice (A2R) connected to the main flow path (2) and to the first right working flow path (5)
Implementation Method 2
a measuring motor (7) arranged in one of the first left working flow path (4) and the right working flow path (5)... The measuring motor is actuated in one direction, when the hydraulic fluid flows from the working port arrangement to the left working port and is actuated in the other direction when the hydraulic flows reverse
Data Source
AI summary
A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a first working port arrangement having a first left working port (L1) connected to a first left working flow path (4) and a first right working port (R1) connected to a first right working flow path (5), a variable first left orifice (A2L) connected to the main flow path (2) and to the first left working flow path (4), a variable first right orifice (A2R) connected to the main flow path (2) and to the first right working flow path (5), a variable second left orifice (A3L) connected to the first left working flow path (4) and to the tank flow path (3), a variable second right orifice (A3R) connected to the first right working flow path (5) and to the tank flow path (3), and a second working port arrangement having a second left working port (12) connected to a second left working flow path (9) and a second right working port (R2) connected to a second right working flow path (10), wherein the variable first left orifice (A2L) is connected to the second left working flow path (9) and the variable first right orifice (A2R) is connected to the second right working flow path (10).