Planetary Gear Axial Preload Structure for Roll Stabilizer Actuators

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Solution Overview

Problem

Existing multi-stage planetary gear arrangements for adjustable roll stabilizers in vehicles face high assembly efforts and complex axial ball bearings, leading to reduced service life due to wear from relative movements between the planet carrier and sun gear.

Innovation Solution

A gear arrangement with a spring element acting between the planet carrier and sun gear to provide axial preload, supported by a central recess in both components, and a sliding element to reduce friction, allowing for axial play compensation and extended service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional linear actuator mechanism is used, then the actuator can achieve linear motion, but the actuator requires a large amount of space and has a complex structure

Engineering Contradiction:
Improveactuator sizeVSAvoidmechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical linear actuator mechanism with a magnetic field-based system. A coil assembly generates a magnetic field that interacts with a ferromagnetic material on the plunger to produce linear motion, eliminating the need for complex mechanical components such as gears, linkages, and cam mechanisms found in traditional actuators.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating principle from mechanical force transmission to electromagnetic force generation. By varying the electrical current through the coil assembly, the magnetic field strength is adjusted to control the plunger's position and motion, enabling compact actuator design with simplified structure.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a conventional linear actuator mechanism is used, then the actuator can achieve linear motion, but the actuator is difficult to control precisely

Engineering Contradiction:
Improveposition control precisionVSAvoidcontrol difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent incorporates a feedback mechanism where a sensor detects the plunger's position and feeds this information back to the control system. The controller adjusts the coil current accordingly to maintain precise position control, enabling accurate positioning while simplifying the control process through automated feedback regulation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The replacement of mechanical control mechanisms with an electromagnetic system allows for more precise and easier control. The magnetic field can be adjusted continuously and rapidly by varying the electrical current, providing fine control over plunger position without the mechanical play and wear inherent in traditional mechanical actuators.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If a cam mechanism with groove is used, then the actuator can be compact, but the cam groove is prone to wear and requires high manufacturing precision

Engineering Contradiction:
Improveactuator sizeVSAvoidcam groove durability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent eliminates the cam mechanism entirely by using a magnetic field to directly actuate the plunger. This substitution removes the cam groove that is susceptible to wear, thereby improving reliability while maintaining the compact form factor achieved through the efficient electromagnetic design.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a ferromagnetic material on the plunger that can be magnetically attracted by the coil assembly. This material choice enables reliable and durable magnetic interaction without the wear problems associated with mechanical cam grooves, combining magnetic properties with structural integrity.

Inventive Principle:
Principle #40Composite materials

4Use of energy by moving object

If a conventional linear actuator mechanism is used, then the actuator can achieve linear motion, but the actuator consumes excessive energy

Engineering Contradiction:
Improveenergy consumptionVSAvoidactuator efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent replaces the energy-intensive mechanical actuator mechanism with an electromagnetic system. The coil assembly converts electrical energy directly into magnetic force to move the plunger, eliminating energy losses associated with mechanical friction, gear inefficiencies, and mechanical component wear, thereby improving overall energy efficiency and reducing power consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces assembly complexity, enhances service life by compensating for axial play, and minimizes wear through axial preload and friction reduction, effectively addressing the limitations of prior designs.

Implementation Method 1

a coil assembly (142) positioned on the interior of the actuator body and configured to generate a magnetic field; a plunger (132) positioned within the actuator body and including a ferromagnetic material

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP3837454B1Gearwheel arrangement and actuator
Publication Date: 2024.07.24 ZF FRIEDRICHSHAFEN AG
  • EP3837454B1 patent drawingFigure 1
  • EP3837454B1 patent drawingFigure 2
  • EP3837454B1 patent drawingFigure 3~3c

AI summary

A gearwheel arrangement (10) of an in particular multi-stage planetary gearing (8) for an actuator (2) of an adjustable roll stabilizer (1), having a sun gear (11), a planet carrier (12) and, connected to the planet carrier (12), planet gears (13) in meshing engagement with the sun gear (11), said sun gear (11) and planet carrier (12) being rotatable about a common rotation axis (3) and supported axially on each other, is characterized by a spring element (14) which acts between planet carrier (12) and sun gear (11) so as to provide axial pretensioning.