Thin Pressure Sensor for Carbon Brush Wear Prevention

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Solution Overview

Problem

Existing pressure sensors are too large to measure spring resilience effectively between carbon brushes and their contact surfaces in carbon brush electric machines, due to limited space and varying pressure ranges, leading to uneven wear and potential damage.

Innovation Solution

A thin pressure sensor with a mechanically deformable section and measuring strips that detect shearing deformation, allowing for precise pressure measurement between the brush and contact surface, with a thickness of less than 4 mm and a wide pressure range, suitable for both stationary and traction engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing pressure sensors are used to measure spring resilience, then pressure measurement capability is provided, but the sensor size is too large to fit in the limited space between the carbon brush and contact surface

Engineering Contradiction:
Improvepressure measurement capabilityVSAvoidsensor size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The sensor is divided into distinct functional components: a flexible printed circuit board carrying measuring strips, a separate mechanically deformable section with target, and a holder structure. This segmentation allows each component to be optimized independently and assembled in a compact configuration that fits within the 2-3mm space constraint while maintaining measurement capability across the required pressure range.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If the sensor thickness is reduced to fit in limited space, then space constraint is satisfied, but the pressure measurement range and sensitivity are compromised

Engineering Contradiction:
Improvesensor thicknessVSAvoidpressure measurement range
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The sensor achieves a wide pressure measurement range (0.1 Kg to 6 Kg) through careful selection and optimization of material parameters including the flexibility modulus of the deformable section, the orientation and configuration of measuring strips, and the geometric dimensions of the target and holder. This allows the thin sensor structure to maintain sufficient sensitivity and adaptability across the full pressure spectrum required for both stationary and traction engines.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single sensor design is used for all applications, then device complexity is reduced, but the sensor cannot accommodate different pressure ranges and space constraints for various engine types

Engineering Contradiction:
Improvesensor design varietyVSAvoidapplication range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The sensor design incorporates universal features including a standardized holder interface, adjustable target positioning, and configurable measuring strip arrangements that allow the same basic sensor structure to be adapted for different applications. By modifying parameters such as target dimensions, deformable section geometry, and measuring strip configuration, the sensor can serve both stationary engines with lower pressure requirements and traction engines requiring higher pressure measurement capability, eliminating the need for completely different sensor designs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The sensor provides accurate and sensitive pressure measurement with high sensitivity and a wide range, capable of measuring pressures from 1 g to 10 kg, and can be deployed directly between the brush and contact surface, preventing uneven wear and damage.

Implementation Method 1

measuring strips (2), which have been designed as such that it/they can detect the shearing of the mechanically deformable section under pressure

Methodology Applied
Scientific EffectShearing deformation: Shear Stress

Implementation Method 2

mechanically deformable section (3), in a recess (5) in the sensor

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3201586B1Pressure sensor containing mechanically deforming elements
Publication Date: 2020.03.11 MERSEN BENELUX BV
  • EP3201586B1 patent drawingFigure 1
  • EP3201586B1 patent drawingFigure 2A~2C
  • EP3201586B1 patent drawingFigure 3~4

AI summary

The invention has the objective of offering a sensor the allows for measuring the pressure force of the springs on the carbon brushes as well as the actual brush pressure on its contact surface. This is obtained by measuring between the carbon brush, and there is limited space through its holder, and the contact surface and is therefore characterized by the fact that the sensor is thinner than 4 mm, and that it is provided with a target (4) which is suspended in the sensor (1) by means of a mechanically deformable section (3), and where the sensor is fitted with one or more strain gauges (2) that is/are set up as such that it can detect the shearing of the mechanical deformable measuring section under pressure. In contrast to the existing measuring sensors, the measuring strips also connect the suspension points of the mechanically deformable elements with the sensor and/or the suspended target or measuring point through which sensitivity increases and makes the sensor useful for such applications.