Planetary Gear Flange Ring Gear Bore Alignment

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Solution Overview

Problem

Existing planetary gear transmissions face challenges in achieving a space-saving design that ensures a secure and backlash-free connection between the flange and ring gear, while minimizing noise and preventing radial deformation of the cylindrical transmission housing.

Innovation Solution

The configuration involves overlapping and offset flange and ring gear bores, with pins inserted via a press fit to securely clamp the flange and ring gear together, ensuring axial and radial securing without radial deformation, and using a spline to prevent twisting, thereby improving noise behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the flange and ring gear are connected using conventional alignment (non-overlapping bores), then the manufacturing and assembly process is simpler, but the connection exhibits radial play and twisting, leading to increased noise and reduced precision

Engineering Contradiction:
Improveconnection stabilityVSAvoidbore alignment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from conventional radial alignment to axial overlapping alignment of bores. The flange bore and ring gear bore are arranged to overlap in the axial direction with an offset difference, creating a three-dimensional connection geometry that simultaneously achieves secure clamping and prevents radial twisting through the pin's interaction with both reference surfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pin serves as an intermediary element that mediates between the flange and ring gear. By pressing the pin into the overlapping and offset bores, the ring gear projection is pressed against the flange stop, firmly bracing the ring gear with the flange in the axial direction while maintaining reference surface contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the flange and ring gear are tightly clamped together, then radial play is eliminated, but radial forces and potential deformation of the cylindrical transmission housing increase

Engineering Contradiction:
ImproveconcentricityVSAvoidradial stress
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The clamping force is applied primarily in the axial direction through the overlapping bore configuration, rather than radially. The pin pressed into the offset bores creates axial compression that eliminates radial play without generating harmful radial stresses that would deform the transmission housing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The reference surfaces on the flange projection and ring gear projection provide localized contact areas that distribute the clamping force. This localized surface contact ensures concentricity and prevents play while concentrating stresses in controlled areas rather than distributing them radially across the housing.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If axial overlapping and offset bore configuration is used, then backlash-free connection and noise reduction are achieved, but the manufacturing and assembly process becomes more complex

Engineering Contradiction:
Improvenoise levelVSAvoidassembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The noise reduction benefit is achieved by changing the bore alignment from conventional radial positioning to axial overlapping with offset. This three-dimensional configuration eliminates radial twisting and backlash, preventing the sources of noise without requiring additional noise control components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The overlapping and offset bore configuration is designed to automatically guide the pin into the correct position during assembly. The geometric relationship between the bores pre-determines the alignment, reducing the need for complex adjustment procedures while achieving the backlash-free connection.

Inventive Principle:
Principle #10Preliminary action

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 configuration provides a secure, backlash-free connection that maintains concentricity and reduces noise by minimizing radial forces and deformations, ensuring a concentric and noise-improved planetary gear operation.

Implementation Method 1

The pair of a radial flange bore (13) and a radial ring gear bore (23) is arranged at least partially overlapping in the axial direction... with a pin (4) being guided through these bores, thereby tightly clamping the flange (10) and the ring gear (20) together

Methodology Applied
Scientific EffectPress fit:

Data Source

PatentEP2241781B2Gear, in particular planetary gear with a flange and a hollow wheel
Publication Date: 2015.03.25 IMS GEAR GMBH
  • EP2241781B2 patent drawingFigure 1
  • EP2241781B2 patent drawingFigure 2
  • EP2241781B2 patent drawingFigure 3

AI summary

The invention relates to a gearbox (5) with at least one flange (10, 10*) for adapting the gearbox (5) to a drive component and with at least one ring gear (20, 20*) which is rigidly connected to the flange (10, 10*) on the gearbox side. A connection is advantageous in that the flange (10, 10*) has at least one radial flange bore (13), the ring gear (20, 20*) has at least one radial ring gear bore (23), and a pin (4) passes through a pair of such a radial flange bore (13) and such a radial ring gear bore (23), thereby rigidly clamping the flange (10, 10*) and the ring gear (20, 20*) together. In particular, the flange bore (13) and the ring gear bore (23) are arranged to overlap at least partially in the axial direction and at the same time to be partially offset from each other by an offset difference (v).