Planet Carrier Pin Mounting With Stepped Boss Anti-Rotation Lock

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Solution Overview

Problem

Existing planetary transmissions face challenges in securely mounting carrier pins to a carrier body, particularly in preventing rotation relative to the carrier plates, which affects the stability and efficiency of the transmission.

Innovation Solution

The design incorporates carrier pins with axial ends featuring recesses that deform against stepped pin bosses on the carrier plates, creating an interlocking mechanism to inhibit rotation and securely fasten the pins to the carrier body, while also using connector sections and optional riveting for additional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carrier pins are mounted in pin bores with screws extending through carrier plates, then the pins are secured to the carrier body, but the structure becomes complex and the pins may still rotate relative to the carrier plates

Engineering Contradiction:
Improvesecurement of carrier pinsVSAvoidmounting structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thin wall sections of the carrier pins deform against the stepped exterior surfaces of the pin bosses to automatically retain the pins and inhibit rotation, eliminating the need for additional screws or complex fastening mechanisms

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The thin wall sections act as an intermediary element between the carrier pins and the stepped pin bosses, transferring and distributing loads while preventing rotation through deformation against the stepped surfaces

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If carrier pins are fixedly mounted to prevent rotation, then transmission stability improves, but the manufacturing process becomes more difficult

Engineering Contradiction:
Improvetransmission stabilityVSAvoidpin mounting ease
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The pin bosses are pre-formed with stepped exterior surfaces that will deform the thin wall sections of the carrier pins during assembly, automatically creating the anti-rotation mechanism before the pins are fully installed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The thin wall sections of the carrier pins are designed with specific geometric parameters that allow them to deform elastically or plastically against the stepped pin boss surfaces, changing from a flexible state during insertion to a locked state after deformation

Inventive Principle:
Principle #35Parameter changes

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

This solution enhances the securement of carrier pins, preventing rotation and ensuring stable operation of the planetary transmission, thereby improving the overall efficiency and reliability of the power transmitting device.

Implementation Method 1

The carrier pins are received through the carrier plates and the thin wall sections are deformed against the exterior surfaces of the pin bosses to retain the carrier pins to the carrier body

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3408563B1Planetary unit having planet carrier with pins fixedly and non-rotatably mounted to carrier body
Publication Date: 2021.10.27 AMERICAN AXLE & MANUFACTURING INC
  • EP3408563B1 patent drawingFigure 1
  • EP3408563B1 patent drawingFigure 2~3
  • EP3408563B1 patent drawingFigure 4~5

AI summary

A planetary transmission having a planet carrier with a carrier body and a plurality of carrier pins. The carrier body includes a pair of carrier plates, each of which having pin bosses that extend outwardly from a remaining portion of the carrier plate. The pin bosses on at least one of the carrier plates define an exterior surface with at least one step so that portions of the exterior surface of the pin bosses are spaced apart in an axial direction. The carrier pins have an axial ends with recesses formed therein such that each axial end of each carrier pin terminates in a thin wall section. The carrier pins are received through the carrier plates and the thin wall sections are deformed against the exterior surfaces of the pin bosses to retain the carrier pins to the carrier body.