Composite Planet Carrier for High Torque Actuator

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Solution Overview

Problem

Existing planetary gears in motor vehicle actuators face deformation issues with plastic planet carriers under high torque conditions, leading to potential damage and misalignment with the transmission housing, while an all-metal design is impractical due to forming limitations and an all-plastic design fails to transmit sufficient torque.

Innovation Solution

A planetary gear design featuring a metal planet holder with a plastic connecting means that completely encloses it, providing increased rigidity and ensuring torque transmission without damaging the connecting means, allowing for high torque transmission while maintaining stability and reducing the risk of deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the planet carrier is made of plastic, then the manufacturing cost is reduced and ease of manufacture is improved, but the rigidity and torque transmission capability deteriorate under high torque conditions

Engineering Contradiction:
Improveease of manufactureVSAvoidtorque transmission capability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The planet carrier is constructed as a composite component with a metal planet holder providing structural strength and rigidity, combined with a plastic connecting means that encloses the planet holder. This composite structure enables the carrier to transmit high torques while maintaining manufacturing advantages of plastic components.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If the planet carrier is made of plastic, then the manufacturing complexity is reduced, but the stability and resistance to deformation worsen under high torque

Engineering Contradiction:
Improvedevice complexityVSAvoidstability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The composite design combines a metal planet holder for stability with a plastic connecting means, achieving high stability under torque while keeping the overall structure relatively simple and maintaining manufacturing advantages.

Inventive Principle:
Principle #40Composite materials

3Strength

If an all-metal planet carrier is used, then the torque transmission capability and strength are improved, but the forming technology and manufacturing feasibility deteriorate

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidease of manufacture
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Instead of creating a complex all-metal carrier, the invention uses a composite structure where only the critical load-bearing planet holder is made of metal, while the connecting means is made of plastic, achieving high strength while maintaining manufacturing feasibility.

Inventive Principle:
Principle #40Composite materials

4Reliability

If the planet carrier is made of plastic, then the cost is reduced, but the risk of damage to the connecting means under high torque increases

Engineering Contradiction:
Improvecost-effectivenessVSAvoidrisk of damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The composite structure with metal planet holder and plastic connecting means optimizes the distribution of mechanical stresses, protecting the connecting means from damage while maintaining cost-effectiveness compared to all-metal designs.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2808582B1Planetary gear of a motor vehicle actuator
Publication Date: 2019.07.10 KUSTER HLDG GMBH
  • EP2808582B1 patent drawingFigure 1
  • EP2808582B1 patent drawingFigure 2~3
  • EP2808582B1 patent drawingFigure 4~5

AI summary

The invention relates to a planetary gear set for a motor vehicle actuator with a planet carrier. The planet carrier has a planet holder for holding planet gears and a connecting element, non-rotatably connected to the planet holder, for connecting the planet holder to an output shaft. The planet holder is made of a stiffer material than the connecting element.