Split Motor Rubber Joint Assembly with Pre-Vulcanized Interference Fit

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Solution Overview

Problem

Existing motor rubber joints for CR300 electric multiple units do not meet the requirements for small radial-axial rigidity ratio and are difficult to assemble, leading to potential loosening and increased maintenance costs.

Innovation Solution

A split motor rubber joint assembly method involving vulcanizing rubber layers between an I-shaped spindle and a split sleeve, followed by pressing the vulcanized structure into an overall sleeve through interference fit, with non-concave free surfaces and specific gaps to ensure isotropic radial characteristics and improved axial rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a traditional motor rubber joint is used, then the assembly process is complex and time-consuming, but the assembly method is difficult and requires multiple steps

Engineering Contradiction:
Improveassembly efficiencyVSAvoidassembly process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The rubber joint is divided into multiple independent rubber pieces (first rubber piece, second rubber piece, third rubber piece) that can be assembled separately and then combined. This segmentation allows for simpler individual assembly steps while achieving the complete joint structure, directly resolving the contradiction between assembly efficiency and process complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the rubber joint is assembled without pre-vulcanization, then the assembly is simpler, but the product reliability is poor and components may loosen

Engineering Contradiction:
Improveproduct reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The rubber pieces are pre-vulcanized and bonded to the spindle before final assembly into the joint structure. This preliminary action ensures strong, reliable bonding that prevents loosening during operation, while the pre-prepared state of components actually simplifies the final assembly process, resolving the contradiction between reliability and manufacturing ease.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the rubber joint is designed for CR300 electric multiple units, then the rigidity ratio meets requirements, but the assembly difficulty increases

Engineering Contradiction:
Improverigidity ratio precisionVSAvoidassembly ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The complex rubber joint structure required for precise rigidity ratio control is segmented into multiple simpler rubber pieces that can be individually manufactured and assembled. This segmentation maintains the precision of the rigidity ratio (30:10 ±20%) while significantly improving assembly ease, as each piece is simpler to manufacture and position than a single complex monolithic rubber component.

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

The method simplifies assembly, enhances product reliability, reduces maintenance costs, and provides a stable motor suspension by ensuring the motor rubber joint has a radial-axial rigidity ratio of 30:10 (±20%) and acts as a lateral stop during train operation.

Implementation Method 1

vulcanizing rubber layers between an I-shaped spindle with a mounting structure and a split sleeve

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Implementation Method 2

pressing a vulcanized overall structure into an overall sleeve through interference fit

Methodology Applied
Scientific EffectInterference fit: Friction

Implementation Method 3

A rubber joint is a frequently-used rubber to metal part of elastic components for shock vibration and damping purpose

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 4

the motor rubber joint is required to achieve flexible connection and vibration and noise reducing purpose

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3620680B1Assembly method of split motor rubber joint and motor rubber joint
Publication Date: 2025.08.27 ZHUZHOU TIMES NEW MATERIAL TECHNOLOGY CO LTD
  • EP3620680B1 patent drawingFigure 1~2
  • EP3620680B1 patent drawingFigure 3~4

AI summary

An assembly method of a split motor rubber joint for a vehicle and a motor rubber joint, adopts a mode of vulcanizing rubber layers (2) between an I-shaped spindle (1) with a mounting structure and a split sleeve (3) and then pressing the vulcanized overall structure into an overall sleeve (4) through interference fit to form a motor rubber joint with a small radial-axial rigidity match property, and it can function as a lateral stop for the motor during train operation by increasing the axial rigidity. The present invention of fully vulcanizing the split sheath (3) to the surface of the I-shaped spindle (1) with mounting structures on both ends at one time only and then pressing the split sheath (3) into an overall sleeve (4) through interference fit, thereby simplify the assembly procedure and obviously increasing production efficiency.