MacPherson Suspension Height Adjustment Actuator

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Solution Overview

Problem

Existing hydraulic linear actuators cannot be used on MacPherson suspensions for steering wheels due to the free rotation of the cylinder and plunger relative to each other, which prevents adjustment of vehicle height.

Innovation Solution

A hydraulic linear actuator adjustment device is integrated between the damper cylinder and the bottom spring plate, with anti-rotation means such as prismatic guides and radial projections to prevent rotation, allowing controlled height adjustment on MacPherson suspensions for steering wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a hydraulic linear actuator is used as an adjustment device, then the device can control vehicle height without increasing suspension vertical size, but the cylinder and plunger are free to rotate relative to each other, preventing use on MacPherson suspensions for steering wheels

Engineering Contradiction:
Improvevertical size of suspensionVSAvoidrotational stability of actuator components
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces asymmetric guide surfaces (prismatic guides) between the cylinder and plunger that allow linear movement but prevent rotation. The guide surfaces are shaped such that they provide mechanical guidance in the axial direction while blocking rotational motion, creating an asymmetric constraint that resolves the free rotation problem without affecting the compact vertical size of the suspension.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces guide means (prismatic guides and radial projections) as intermediary elements between the cylinder and plunger. These guide means act as mediators that transmit the hydraulic force for height adjustment while simultaneously preventing relative rotation, thus enabling the hydraulic actuator to function reliably on MacPherson suspensions for steering wheels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the adjustment device is mounted between the damper cylinder and bottom spring plate, then it can adjust vehicle height without increasing suspension size, but the free rotation of components prevents controlled adjustment on steering wheel suspensions

Engineering Contradiction:
Improvecontrolled height adjustmentVSAvoidrelative rotational position of actuator parts
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The prismatic guides create an asymmetric mechanical constraint that allows controlled linear movement for height adjustment while preventing rotational movement. This asymmetric design ensures that the plunger can extend and retract for height control but cannot rotate relative to the cylinder, providing the rotational stability needed for controlled operation on steering wheel suspensions.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The guide means serve as intermediary elements that mediate between the hydraulic actuation force and the structural mounting points. They enable the controlled height adjustment function while simultaneously stabilizing the relative rotational position of the actuator components, thus achieving both ease of operation and compositional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a linear actuator is used for height adjustment, then vehicle height can be controlled, but the actuator cannot be used on MacPherson suspensions for steering wheels due to free rotation about the actuator axis

Engineering Contradiction:
Improveapplicability to different suspension typesVSAvoidrotational stability of cylinder and plunger
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The asymmetric prismatic guide surfaces create a mechanical constraint that is specific to the linear movement direction while blocking rotational movement. This asymmetric design makes the actuator adaptable to MacPherson suspensions for steering wheels, which require rotational stability, without sacrificing the height adjustment functionality.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The guide means serve multiple functions: they guide the linear movement of the plunger for height adjustment and simultaneously prevent rotational movement. This multi-functionality enables the hydraulic actuator to be universally applied to MacPherson suspensions for steering wheels, combining height adjustment capability with rotational stability in a single integrated solution.

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

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

Enables controlled adjustment of vehicle height on MacPherson suspensions for steering wheels without increasing suspension size, allowing for both maximum and minimum height settings.

Implementation Method 1

a hydraulic linear actuator... interposed between a part of the suspension drivingly connected to the wheel-carrier and a bottom end of the spring of the suspension

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2709861B1Macpherson vehicle suspension comprising a device for adjusting the height of the vehicle body from the ground
Publication Date: 2015.05.13 SISTEMI SOSPENSIONI SPA
  • EP2709861B1 patent drawingFigure 1
  • EP2709861B1 patent drawingFigure 2~3
  • EP2709861B1 patent drawingFigure 4

AI summary

The suspension comprises a damper and spring unit (10) with a damper (12), a spring (14) and an adjustment device (16) for adjusting the height of the vehicle from the ground. The adjustment device (26) is made as a hydraulic linear actuator and comprises a cylinder (28) and a plunger (30). The adjustment device (26) is interposed between the cylinder (16) of the damper (12) and the spring (14) to change in a controlled manner the linear position of the bottom end of the spring (14) relative to the cylinder (16) of the damper (12) along the axis (Z) of this latter. The adjustment device (26) further comprises a sleeve (38) which is firmly secured to the cylinder (16) of the damper (12) and on which the cylinder (28) of the adjustment device (26) is fitted. The adjustment device (26) further comprises anti-rotation means (48, 50) for preventing relative rotation of the sleeve (38) and of the plunger (30) of the adjustment device (26) about the axis (Z) of the cylinder (16) of the damper (12). These anti-rotation means (48, 50) are advantageously made as guide means adapted to allow the plunger (30) to slide relative to the sleeve (38) of the adjustment device (26) along the axis (Z) of the cylinder (16) of the damper (12).