Rotary Spool Valve Active Suspension for Precise Hydraulic Force Control

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Solution Overview

Problem

Existing active vehicle suspensions face challenges in efficiently controlling the force generated by hydraulic actuators due to the use of translating spool valves, which result in larger sizes, non-linear actuation, and increased friction, leading to inefficiencies and potential failure modes.

Innovation Solution

Employing a rotary spool valve configured to connect hydraulic actuator chambers with high-pressure and low-pressure lines, where the electric motor is mounted coaxially with the spool, ensuring linear actuation, reduced size, and minimal delays, while eliminating the need for hydraulic seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive spring and damper elements are used for suspension, then the structure is simple and robust, but the wheel contact patch becomes unstable over rough terrain and ride comfort deteriorates

Engineering Contradiction:
Improvewheel contact patch stabilityVSAvoidsuspension system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies active dynamics by replacing passive suspension elements with an active suspension system that continuously adjusts damping forces based on real-time road conditions and vehicle state. The control system processes sensor data and dynamically modulates the damping characteristics of the suspension dampers, allowing the system to adapt to varying terrain and maintain optimal wheel contact patch stability without requiring a completely complex mechanical structure.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If active suspension control is implemented, then ride comfort and contact patch stability improve, but the system complexity and cost increase

Engineering Contradiction:
Improveride comfortVSAvoidsuspension system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by designing a control system that simultaneously performs multiple functions: monitoring wheel position, calculating contact patch stability, determining road surface conditions, and adjusting damper forces. This integrated approach allows the same electronic control unit and sensor array to serve multiple purposes, improving ride comfort and contact patch stability without proportionally increasing system complexity or cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If heavy-duty suspension components are used for towing, then towing capacity increases, but the suspension becomes overly stiff and ride comfort on normal terrain deteriorates

Engineering Contradiction:
Improvetowing capacityVSAvoidride comfort
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent applies dynamic adjustment to suspension stiffness by using active damping control that adapts to loading conditions. When towing is detected through sensor inputs, the system increases damping forces to handle the additional load and maintain towing capacity. When towing is not present, the system automatically reduces damping stiffness to provide a comfortable ride on normal terrain, eliminating the need for permanently heavy-duty components.

Inventive Principle:
Principle #15Dynamics

4Reliability

If suspension tuning is optimized for one terrain type, then performance on that terrain improves, but performance on other terrains deteriorates

Engineering Contradiction:
Improvesuspension performanceVSAvoidterrain adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptability through real-time damping adjustment based on detected terrain conditions. The control system continuously monitors wheel motion, road surface characteristics, and vehicle response to automatically tune suspension parameters for the current terrain type. This allows the suspension to optimize performance for rock crawling, trail riding, or pavement driving as conditions change, eliminating the need for manual reconfiguration or terrain-specific suspension setups.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4453457B1Active suspension for a vehicle
Publication Date: 2026.04.29 WAY ASSAUTO
  • EP4453457B1 patent drawingFigure 1
  • EP4453457B1 patent drawingFigure 2
  • EP4453457B1 patent drawingFigure 3

AI summary

The suspension (10) includes a hydraulic actuator (12) and a supply hydraulic circuit (14) connected to the hydraulic actuator (12) to supply a compression chamber (20) and an extension chamber (22) of the hydraulic actuator (12) with a working fluid. The supply hydraulic circuit (14) includes a hydraulic pump (26), a high-pressure line (28) connected to a delivery port (30) of the hydraulic pump (26), a low-pressure line (32) connected to a suction port (34) of the hydraulic pump (26), and a flow control valve (36) connected on one side to the compression chamber (20) and extension chamber (22) of the hydraulic actuator (12) and on the other side to the high-pressure line (28) and low-pressure line (32). The flow control valve (36) is a rotary spool valve comprising a spool (40) which is rotatable continuously between a plurality of operating positions comprised, in a first direction, between a rest position and a first end operating position and, in a second direction opposite the first direction, between the rest position and a second end operating position. The flow control valve (36) is configured such that in each operating position of the spool (40) between the first end operating position and the second end operating position it connects at least one of the compression chamber (20) and the extension chamber (22) of the hydraulic actuator (12) with the high-pressure line (28).