Planetary Gear Train for Automatic Transmission with Nested Sets

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Solution Overview

Problem

Automatic transmissions with increased shift stages face challenges in installability, production cost, weight, and power flow efficiency due to the need for more parts, which complicates achieving better fuel consumption and drivability.

Innovation Solution

A planetary gear train configuration with three single pinion planetary gear sets and six engagement elements, including five clutches and one brake, allowing for at least ten forward speeds and one reverse speed, optimizing torque delivery and reducing the number of parts required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the number of planetary gear sets and engagement elements is increased to achieve more shift stages, then the fuel consumption and drivability are improved, but the installability, production cost, weight and power flow efficiency deteriorate

Engineering Contradiction:

Improvefuel consumptionVSAvoidnumber of parts

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines multiple planetary gear sets (first, second, and third planetary gear sets) into a single integrated transmission assembly where gear elements are shared between sets. This merging approach enables achievement of multiple shift stages (improving fuel consumption) while reducing the total number of discrete parts compared to using separate planetary gear sets for each shift stage.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear sets are designed with universal elements that serve multiple functions. For example, the first ring gear serves as both a gear element in the first planetary gear set and as a structural component for the second planetary gear set. This multi-functionality allows the system to achieve more shift stages without proportionally increasing the number of parts.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Use of energy by moving object

Engineering Contradiction:

Improvefuel consumptionVSAvoidtransmission length

Core Design Contradiction:

Use of energy by moving objectVSLength of stationary object

Solution Approach 1:

The patent employs a nested arrangement where the second planetary gear set is positioned within or alongside the first planetary gear set, and the third planetary gear set is similarly integrated. This nesting allows multiple gear sets to occupy overlapping or adjacent spaces, reducing the overall axial length of the transmission while enabling multiple shift stages for improved fuel consumption.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of arranging planetary gear sets in a linear sequence along the axial direction, the patent utilizes radial and axial positioning to create a three-dimensional compact layout. This dimensional optimization reduces the transmission length while maintaining the capability for multiple shift stages.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Use of energy by moving object

Engineering Contradiction:

Improvefuel consumptionVSAvoidtransmission weight

Core Design Contradiction:

Use of energy by moving objectVSWeight of stationary object

Solution Approach 1:

The patent merges multiple planetary gear sets into a single integrated assembly where structural components such as ring gears and planet carriers are shared between different gear sets. This consolidation reduces the total material required and eliminates redundant components, thereby reducing transmission weight while still achieving multiple shift stages for improved fuel consumption.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs composite construction methods where multiple functional elements are integrated into unified components. For example, the first ring gear serves dual purposes as both a gear element and a structural support for subsequent planetary gear sets, reducing overall material usage and weight while maintaining strength and functionality across multiple shift stages.

Inventive Principle:

Principle #40Composite materials

4Use of energy by moving object

Engineering Contradiction:

Improvefuel consumptionVSAvoidproduction cost

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent combines multiple planetary gear sets into a single integrated transmission assembly where components such as ring gears and planet carriers are shared across different gear sets. This merging reduces the total number of discrete parts that need to be manufactured, assembled, and quality-checked, thereby reducing production cost while enabling multiple shift stages for improved fuel consumption.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear sets are designed with universal elements that perform multiple functions. For example, the first ring gear serves as both a gear element in the first planetary gear set and as a structural component for the second planetary gear set. This multi-functionality reduces the number of unique components that need to be manufactured, simplifying production and reducing costs while achieving multiple shift stages.

Inventive Principle:

Principle #6Universality (Multi-functionality)

5Use of energy by moving object

Engineering Contradiction:

Improvefuel consumptionVSAvoidtransmission axial length

Core Design Contradiction:

Use of energy by moving objectVSLength of moving object

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of arranging planetary gear sets in a linear sequence along the axial direction, the patent utilizes radial and axial positioning to create a three-dimensional compact layout. This dimensional optimization reduces the transmission axial length while maintaining the capability for multiple shift stages.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10344832B2Planetary gear train of automatic transmission for vehicle

Publication Date: 2019.07.09 HYUNDAI MOTOR CO LTD

AI summary

A planetary gear train may include input and output shafts, first to third planetary gear sets respectively having first to third, fourth to sixth, and seventh to ninth elements, a first shaft connected to the first element, and selectively connectable to the input shaft, a second shaft connected to the fifth element, and selectively connectable to the input shaft, a third shaft connected to the eighth element and the output shaft, a fourth shaft connected to the second element and the fourth element, a fifth shaft connected to the third and seventh elements, a sixth shaft connected to the sixth element and the transmission housing, and a seventh shaft connected to the ninth element and selectively connectable to the transmission housing.