Motor Rotating Shaft Oil Pipe Assembly With Sequential Interference Fit

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current motor cooling technologies face challenges in efficiently assembling and securing cooling liquid pipes within motor rotating shafts, leading to increased assembly difficulty and potential detachment due to rotation or vibration.

Innovation Solution

The motor rotating shaft features a rotating shaft body with a cavity and two holes, where an oil pipe is inserted to form an interference fit with one hole first, then the other, reducing assembly resistance and enhancing connection strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the oil pipe is inserted into both holes simultaneously to form interference fits, then the connection strength is maximized, but the assembly difficulty increases due to high assembly resistance

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly difficulty
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies preliminary action by first forming the interference fit with one hole (first interference fit) before forming the interference fit with the other hole (second interference fit). This sequential approach reduces the total assembly resistance compared to simultaneous insertion, as the oil pipe gradually engages with the holes rather than encountering full resistance from both holes at once.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the oil pipe forms interference fit with both holes, then the connection strength increases, but the device complexity increases due to multiple fitting surfaces and holes

Engineering Contradiction:
Improveconnection strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the connection process into two separate interference fits - one with the first hole and one with the second hole. The oil pipe is designed with different fitting surfaces (first fitting surface and second fitting surface) that engage with each hole sequentially, breaking down the complex simultaneous fitting task into manageable segments.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If a single hole is used for inserting the oil pipe, then the assembly process is simplified, but the connection strength and reliability are reduced due to only one interference fit

Engineering Contradiction:
Improveassembly process simplicityVSAvoidconnection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses preliminary action by establishing the first interference fit as a preliminary step before completing the second interference fit. This sequential engagement ensures that the oil pipe is progressively secured, maintaining reliability while allowing for a controlled, step-by-step assembly process rather than requiring complex simultaneous alignment.

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 reduces assembly difficulty, increases the connection strength between the oil pipe and the rotating shaft body, and prevents the oil pipe from detaching during operation, ensuring normal running of the motor rotating shaft.

Implementation Method 1

the oil pipe is configured to form an interference fit with the one used as a non-inserting hole in the first hole and the second hole first, and then to form an interference fit with the other one used as an inserting hole in the first hole and the second hole

Methodology Applied
Scientific EffectInterference fit: Friction

Data Source

PatentEP4546615A1Motor rotating shaft, assembly method of motor rotating shaft, motor, and vehicle
Publication Date: 2025.04.30 XIAOMI EV TECH CO LTD
  • EP4546615A1 patent drawingFigure 1
  • EP4546615A1 patent drawingFigure 2~3
  • EP4546615A1 patent drawingFigure 4~5

AI summary

The disclosure relates to a motor rotating shaft, an assembly method of a motor rotating shaft, a motor and a vehicle. The motor rotating shaft (100) includes a rotating shaft body (1) and an oil pipe (2), the rotating shaft body (1) is provided with a cavity (12), a first hole (13) and a second hole (14), and the first hole (13) and the second hole (14) both communicate with the cavity (12). The oil pipe (2) is arranged inside the rotating shaft body (1), and the oil pipe (2) and the rotating shaft body (1) are both provided with through holes (10) for leading cooling liquid in the oil pipe (2) out of the rotating shaft body (). In a process of inserting the oil pipe (2) into the rotating shaft body (1) from either of the first hole (13) and the second hole (14), the oil pipe (2) is configured to form an interference fit with the one used as a non-inserting hole in the first hole (13) and the second hole (14) first, and then to form an interference fit with the other one used as an inserting hole in the first hole (13) and the second hole (14).