Injection Molding Machine Compact Design

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Solution Overview

Problem

Existing injection molding machines have a lengthened configuration due to the external connection of motor-side and screw shaft-side parts, which increases the overall machine length.

Innovation Solution

The injection molding machine design incorporates a rotation transmission shaft that is spline-connected to the rotor inside the injection motor, allowing for a more compact configuration by overlapping the motor bearing and stator coil, thereby reducing the machine's longitudinal length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor-side part and screw shaft-side part are connected outside the motor, then the connection is simple and reliable, but the entire length of the injection molding machine is lengthened

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmachine length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies nesting by placing the rotation transmission shaft inside the motor housing, with the shaft extending through the stator coil. This nested configuration allows the transmission components to be contained within the motor's axial space rather than extending externally, thereby reducing the overall machine length while maintaining the connection functionality between the motor and screw shaft

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent repositions the motor bearing and stator coil to overlap in the axial direction, utilizing the radial dimension more effectively. This dimensional rearrangement allows components that would traditionally be arranged sequentially along the axis to instead occupy overlapping axial spaces, reducing the total axial length of the machine

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the motor bearing and stator coil are arranged sequentially, then the assembly is simple, but the axial dimension increases

Engineering Contradiction:
Improveassembly simplicityVSAvoidaxial dimension
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The patent transitions from a sequential axial arrangement to an overlapping axial arrangement by positioning the motor bearing and stator coil to occupy the same axial space. This dimensional change allows both components to be manufactured and assembled using relatively simple processes while significantly reducing the axial dimension of the overall assembly

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3372378B1Injection molding machine
Publication Date: 2019.12.25 SUMITOMO HEAVY IND LTD
  • EP3372378B1 patent drawingFigure 1
  • EP3372378B1 patent drawingFigure 2
  • EP3372378B1 patent drawingFigure 3

AI summary

The present invention provides an injection molding machine in which the entire length thereof can be shortened. The injection molding machine includes a motor which includes a stator and a rotor, a rotation transmission shaft which is rotated by the motor, a screw shaft which is rotated by a rotation of the rotation transmission shaft, and a screw nut which is screwed to the screw shaft and is moved forward or rearward by a rotation of the screw shaft, in which the motor, the rotation transmission shaft, the screw shaft, and the screw nut are disposed on the same straight line, and the rotation transmission shaft includes a connection shaft portion which is connected to the rotor inside the rotor.