Connecting Device for Electric Motor Testing

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Solution Overview

Problem

Existing electric motor testing devices face challenges in accurately measuring motor performance at constant ambient temperatures due to difficulties in maintaining temperature stability and energy loss from frictional contact during testing, especially for small motors with limited output shaft length.

Innovation Solution

A connecting device with a housing, a three-section connecting shaft, and sealed cavities filled with compressed air to support the shaft, which penetrates the thermostat's side wall and connects the motor to external testing equipment, minimizing friction and maintaining constant temperature conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the output shaft is designed to be very long to connect the electric motor inside the thermostat to external testing equipment, then the connection is achieved, but the output shaft becomes susceptible to tip shaking which influences test result accuracy

Engineering Contradiction:
Improveoutput shaft lengthVSAvoidtest result accuracy
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

A connecting device with a connecting shaft serves as an intermediary component between the electric motor's output shaft and the external testing equipment. The connecting shaft is supported by sealed cavities filled with compressed air that penetrate the thermostat wall, providing stable support and reducing tip shaking while maintaining connection functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connecting shaft is supported by sealed cavities filled with compressed air that penetrate the thermostat wall. The compressed air provides pneumatic support to stabilize the connecting shaft, reducing vibrations and tip shaking, thereby improving measurement precision while maintaining the necessary connection length.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Ease of operation

If the output shaft is directly connected to external testing equipment, then the connection is achieved, but contact friction is formed between the output shaft and the thermostat wall which influences test result accuracy

Engineering Contradiction:
Improveconnection easeVSAvoidtest result accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The connecting device acts as an intermediary structure between the output shaft and the thermostat wall. The housing with sealed cavities provides a dedicated pathway that prevents direct contact between the rotating shaft and the thermostat wall, eliminating friction while maintaining operational connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the electric motor is taken out from the thermostat for performance measurement, then the measurement can be performed, but the electric motor cannot maintain the ambient temperature set in the thermostat which reduces test accuracy

Engineering Contradiction:
Improvetesting efficiencyVSAvoidtest result accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The connecting device serves as an intermediary that enables the electric motor to remain inside the thermostat while still allowing external testing equipment to measure performance. This eliminates the need to remove the motor, maintaining temperature stability and measurement accuracy while preserving testing efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If an anechoic chamber structure with transmission shaft is used for motor testing, then the motor can be tested, but the structure is complex and not suitable for small electric motors with limited output shaft length

Engineering Contradiction:
Improvetesting applicabilityVSAvoidtesting device structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The connecting shaft is divided into multiple sections: a first section inside the thermostat, a second section outside the thermostat, and an intermediate section penetrating the thermostat wall. This segmentation allows the connecting device to be adapted to small electric motors with limited output shaft length while maintaining a relatively simple structure compared to anechoic chamber designs.

Inventive Principle:
Principle #1Segmentation

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

Ensures accurate and real-time measurement of electric motor performance at various ambient temperatures by reducing energy loss and maintaining constant temperature conditions, enhancing the reliability of test results.

Implementation Method 1

at least one sealed cavity is enclosed together by the at least two seals, the outer peripheral wall of the intermediate section and an inner wall of the housing, and is filled with compressed air to support the connecting shaft

Methodology Applied
Scientific EffectAir support: Air Lubrication

Data Source

PatentEP4222512B1Connecting device for electric motor testing and electric motor testing device
Publication Date: 2024.07.17 ZF FRIEDRICHSHAFEN AG
  • EP4222512B1 patent drawingFigure 1
  • EP4222512B1 patent drawingFigure 2

AI summary

The present invention provides a connecting device for electric motor testing and an electric motor testing device. The connecting device comprises a housing, a connecting shaft and at least two seals. The connecting shaft comprises a first section, a second section, and an intermediate section located between the first section and the second section, the first section, the second section and the intermediate section being integrally formed, the intermediate section being located inside the housing, and the first section and the second section being located outside the housing. The at least two seals are sleeved on an outer peripheral wall of the intermediate section and are in tight fit with the housing, and at least one sealed cavity is enclosed together by the at least two seals, the outer peripheral wall of the intermediate section and an inner wall of the housing and is filled with compressed air to support the connecting shaft. The first section is connected to a piece of external electric motor testing equipment, and the second section is connected to an output shaft of an electric motor to be tested in a thermostat. The accuracy of a test result can be ensured at constant ambient temperature.