Integrated Linear-Rotary Direct Drive for Injection Molding
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Solution Overview
Problem
Current plastics injection-molding machines with dual rotary drives for independent or superimposed rotary and linear movements are complex to control, prone to wear, and physically large due to the need for threaded drive mechanisms and axial force absorption by bearings.
Innovation Solution
An integrated electrical direct drive system featuring a rotary motor with its stator inside a linear motor's hollow-cylindrical stator, eliminating the need for threaded mechanisms and axial bearings, and optionally using two linear motors in series for enhanced stiffness and dynamic response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate rotary drives with threaded spindle mechanism are used to achieve independent or superimposed rotary and linear movements, then the required movements can be produced, but the device becomes physically large and complex
Solution Approach 1:
The patent combines two separate rotary drives into a single integrated direct drive system that produces both rotary and linear movements simultaneously. The drive shaft is designed to generate orthogonal movement components in different spatial directions, eliminating the need for separate threaded spindle mechanisms and reducing overall system volume.
Solution Approach 2:
The patent implements a nested structure where the rotary drive components are positioned within or around the linear drive components. The drive shaft with its orthogonal movement generation mechanism is integrated within the housing structure, allowing compact arrangement of functional elements.
2Adaptability or versatility
If two separate rotary drives with threaded spindle mechanism are used, then the required movements can be produced, but the control system becomes complicated
Solution Approach 1:
The patent merges the control of two separate rotary drives into a single control system for the integrated direct drive. By controlling one drive shaft that generates both orthogonal movement components, the control complexity is significantly reduced while maintaining the ability to produce independent or superimposed rotary and linear movements.
3Adaptability or versatility
If threaded drive mechanism and bearings are used to absorb axial forces, then the required movements can be produced, but wear increases significantly
Solution Approach 1:
The patent replaces the threaded drive mechanism with a direct drive system that generates linear movement through orthogonal force components rather than through threaded conversion. This substitution eliminates the threaded mechanism and its associated wear, while the bearing design is optimized to reduce axial force absorption requirements.
4Adaptability or versatility
If the drive system is designed to produce independent or superimposed rotary and linear movements, then versatility is achieved, but the physical size increases
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement to generate orthogonal movement components from a single drive shaft. By arranging force generation elements in different spatial directions and combining their effects, the system achieves versatile movement capability without increasing axial length, as the orthogonal components are generated within the same axial space.
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 results in a low-wear, compact, and easily controllable drive system with improved mechanical stiffness and dynamic response, reducing physical size and operational complexity while avoiding costly wear-prone components.
Implementation Method 1
the linear drive has a first electric linear motor with an external rotor in the form of a pot, in whose interior the majority of a hollow-cylindrical stator of the first linear motor is arranged
Implementation Method 2
the rotary drive has a rotating electric motor whose stator is arranged in the interior of the hollow-cylindrical stator of the first linear motor and is firmly connected to it, and whose rotor is firmly coupled to the output drive shaft
Data Source
AI summary
A plastics injection-molding machine is to be equipped with a more compact drive that undergoes less wear. For this purpose, it is envisaged to integrate the direct rotational drive into the direct linear drive. Accordingly, the electric linear motor has a pot-shaped external rotor (13), in the inner space of which the main part of a hollow-cylindrical stator (16) of the linear motor is arranged and which is firmly connected to the output shaft (10). The rotary drive has a stator (18), which is mounted on the inner wall of the hollow-cylindrical stator (16) of the linear motor, and a rotor, which is firmly coupled to the output shaft (10) within the stator (18) of the rotary electric motor. This direct drive produces a very compact type of construction and it is possible to dispense with easily wearing threaded spindles.