Ring Gear Encasing Torque Transducer for Power Tools

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Power tool drive trains face challenges in protecting torque transducers from operational forces and ensuring accurate torque measurements due to limited space and potential damage from moving parts.

Innovation Solution

A ring gear design with a cylindrical body featuring a first and second portion, where the second portion has a smooth inner surface and is configured to encase a disk-shaped torque transducer, using longitudinally extending rails and slots for secure alignment and protection, allowing the transducer to be held in a locked anti-rotational configuration and maintaining concentric alignment with the drive train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a torque transducer is installed in a power tool drive train, then torque measurement capability is improved, but the transducer is vulnerable to damage from operational forces and moving parts

Engineering Contradiction:

Improvetorque measurement capabilityVSAvoidtransducer durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The ring gear is designed with an internal cavity that houses the torque transducer, nesting the transducer within the gear structure. This protective enclosure shields the transducer from external operational forces and moving parts while maintaining its measurement function within the drive train

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the ring gear wall thickness is increased to protect the transducer, then transducer protection is improved, but the device complexity and space requirements increase

Engineering Contradiction:

Improvetransducer protectionVSAvoidring gear structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The ring gear exhibits varying wall thicknesses at different locations: thicker walls in regions providing structural support and transducer protection, and thinner walls where less protection is needed. This localized variation optimizes protection while minimizing overall complexity and material usage

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If alignment features such as rails and slots are added to the ring gear, then transducer alignment precision is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvetransducer alignment precisionVSAvoidring gear manufacturing complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Alignment features such as rails and slots are pre-formed as integral parts of the ring gear structure during manufacturing. This preliminary incorporation of alignment features ensures precise transducer positioning while eliminating the need for separate alignment operations, thereby reducing overall manufacturing complexity

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2691211B1Ring gears configured to encase in-line torque transducers for power tools

Publication Date: 2017.06.28 INGERSOLL RAND CO

Figure 1
Figure 2
Figure 3

AI summary

Ring gears with a cylindrical ring gear body having a wall with a longitudinal length extending between opposing first and second ends, the wall having an outer surface and an inner surface. The inner surface has a first portion that extends a first sub-length of the ring gear body and a longitudinally spaced apart second portion that extends a second sub-length of the ring gear body. The first portion extends from the first end of the ring gear inward and the second portion extends from the second end of the ring gear inward. The inner surface of the first portion comprises a plurality of longitudinally extending splines and the inner surface of the second portion is devoid of the splines of the first portion.