Hollow Spindle Worm Drive Apparatus for Injection Molding
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Solution Overview
Problem
Existing drive systems for injection molding machines with coaxial worms suffer from long overall design, wear-prone couplings, and rotational play between rotating and linear drives, leading to inefficiencies and reliability issues.
Innovation Solution
A compact drive apparatus with a housing that is axially displaceable and rotationally fixed, featuring a rotational drive and a translational drive configured as electric motors, where the spindle shaft is immovable and hollow, allowing for direct force transmission and minimizing play, with anti-rotation safeguards to eliminate the need for a separate coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coupling system is used to connect rotating and linear drives, then the two independent drive systems can be connected, but the coupling is subject to wear and rotational play
Solution Approach 1:
The patent removes the coupling system entirely from the drive train. The rotating drive (5) and translatory drive (3) are connected directly through the hollow spindle shaft (19), eliminating the wear-prone and play-prone coupling components that would otherwise be needed to connect the two independent drive systems.
Solution Approach 2:
The output shaft (21) is arranged coaxially within the hollow spindle shaft (19), creating a nested configuration. This allows the rotating drive to be transmitted through the hollow interior of the spindle shaft directly to the output shaft, eliminating the need for external coupling mechanisms and reducing both wear and rotational play.
2Adaptability or versatility
If two independent drive systems are used for rotating and linear movement, then each drive can be independently controlled, but the overall design becomes long and complex
Solution Approach 1:
The patent merges the rotating drive (5) and translatory drive (3) into a single integrated housing (9). Both drives operate independently but are spatially combined within the same housing, with the hollow spindle shaft serving as both the translatory element and the transmission path for rotation, thereby reducing overall design complexity while maintaining independent control.
Solution Approach 2:
The hollow spindle shaft (19) is nested within the housing, and the output shaft (21) is nested within the spindle shaft, creating a compact concentric arrangement. This nesting allows both drive systems to coexist in a compact space without requiring separate mounting areas, reducing the overall footprint and simplifying the design.
3Adaptability or versatility
If a coupling system is used to connect drives, then the two drives can be connected, but the overall design becomes longer
Solution Approach 1:
By removing the coupling system entirely, the patent eliminates the additional length that would be required for coupling components and their mounting arrangements. The direct connection through the hollow spindle shaft significantly reduces the axial length of the drive apparatus compared to a design with separate coupling elements.
Solution Approach 2:
The concentric nesting of the output shaft within the hollow spindle shaft allows both rotational and translatory movements to occur within the same axial space, eliminating the need for additional length to accommodate separate coupling mechanisms and reducing the overall design length.
4Adaptability or versatility
If a coupling system is used to connect drives, then the two drives can be connected, but rotational play occurs between the drives
Solution Approach 1:
By eliminating the coupling system, the patent removes the source of rotational play that would otherwise be introduced by coupling tolerances, clearance fits, and mechanical clearances in the coupling components. The direct drive connection through the hollow spindle shaft ensures precise rotational transmission without intermediate play-inducing elements.
5Strength
If a fixed spindle shaft is used, then a reliable abutment is produced, but the housing needs to be displaceable
Solution Approach 1:
The hollow spindle shaft (19) is nested within the housing (9), and the housing is mounted displaceably on the spindle shaft with an anti-rotation safeguard. This nested arrangement allows the housing to displace axially while the fixed spindle shaft provides a reliable non-displaceable abutment, resolving the contradiction between fixed stability and displacement capability.
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 solution achieves a compact, reliable, and play-free coupling, optimizing force flow and reducing the risk of failure by ensuring rigid attachment and minimizing load on critical components, thus enhancing the overall design and performance of the drive system.
Implementation Method 1
The rotational drive (5) and the translatory drive (3) are configured in each case as electric motors
Data Source
AI summary
Drive apparatus (1, 101), in particular for driving a worm of an injection molding machine, which worm is arranged coaxially with respect to an injection molding cylinder, having a housing (9, 109) which is mounted such that it can be displaced in an axial direction of the housing (9, 109) and is fixed rotationally, an output shaft (21, 121) which is mounted non-displaceably and rotatably in the housing (9, 109), a rotational drive (5) which is arranged in the housing (9, 109) for the rotational drive of the output shaft (21, 121), and a translatory drive (3) which is arranged in the housing (9, 109) for the translatory drive of the housing (9, 109).