Ball Screw Lubrication Layout for Injection Molding Machines
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Solution Overview
Problem
In electrically driven injection molding machines, the high load and axial forces lead to significant lubricant loss through inadequate sealing, resulting in contamination of the environment with a mixture of old and fresh grease, necessitating frequent replacement and inefficient lubricant consumption.
Innovation Solution
A plastics processing machine design featuring a ball screw drive with a seal at one axial end and a wiper at the other, where the lubricant feed element is positioned close to the seal, ensuring that lubricant moves through the screw to the wiper for controlled discharge, and a collecting element is used to capture used lubricant, reducing contamination and consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a seal is used to prevent lubricant escape from the threaded nut, then lubricant retention is improved, but used lubricant cannot be discharged and accumulates inside the threaded nut
Solution Approach 1:
The threaded nut is divided into a sealed first axial end region and an open second axial end region. The seal is positioned only at the first axial end region, creating a segmented structure where lubricant can be retained at the injection side while allowing used lubricant to discharge from the opposite side.
Solution Approach 2:
Instead of sealing both ends to prevent all lubricant escape, the invention inverts the approach by sealing only one end (first axial end region) and leaving the other end (second axial end region) open. This allows the system to benefit from both retention and discharge functions simultaneously.
2Object-generated harmful factors
If wipers are used to allow used lubricant to escape, then lubricant discharge is improved, but fresh lubricant is also lost through the wipers
Solution Approach 1:
Different axial regions of the threaded nut are given different sealing qualities. The first axial end region has a seal that prevents lubricant escape, while the second axial end region has a wiper that allows controlled discharge. The feed element is positioned locally at the first axial end region to inject fresh lubricant near the seal.
Solution Approach 2:
The wiper acts as an intermediary element at the second axial end region that mediates between the need to discharge used lubricant and the need to retain fresh lubricant. It allows selective passage based on the lubricant's position and usage state within the threaded nut.
3Reliability
If lubricant is cycled through the ball screw drive, then lubrication effectiveness is improved, but contamination of the surrounding area increases due to grease escape
Solution Approach 1:
The harmful effect of grease escape is extracted and redirected to a specific location (second axial end region with wiper) where it can be contained and collected. This removes the random contamination problem and concentrates the discharge in a controlled manner that can be managed with appropriate collection systems.
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 achieves quasi-forced guidance of lubricant, minimizing fresh grease discharge and ensuring defined removal of used lubricant, thereby reducing lubricant consumption and preventing environmental contamination.
Implementation Method 1
a seal is arranged in the first axial end region of the threaded nut which prevents the escape of lubricant from the threaded nut
Implementation Method 2
a feed element for the addition of lubricant is arranged adjacent to the first axial end region of the threaded nut so that the lubricant can be introduced into the interior of the threaded nut
Implementation Method 3
a threaded drive which has a threaded nut and a threaded spindle for converting a motor's rotary motion into a linear motion
Data Source
Figure 1
AI summary
The invention relates to a plastics processing machine, in particular an injection molding machine, comprising a first component (1) which is arranged to be displaceable relative to a second component (2) in a translational direction (T), wherein at least one threaded drive (3) is provided for carrying out a relative translational movement, wherein the threaded drive (3) comprises a threaded nut (4) which is connected to one of the two components (1), and a threaded spindle (5) which is directly or indirectly connected to the other of the two components (2), wherein the threaded nut (4) has a first axial end region (6) and a second axial end region (7), wherein a seal (8) is arranged in the first axial end region (6) of the threaded nut (4) which prevents the escape of lubricant from the threaded nut (4).and wherein a feed element (10) for the addition of lubricant is arranged adjacent to the first axial end region (6) of the threaded nut (4), with which lubricant can be introduced into the interior of the threaded nut (4). In order to improve the lubrication of the threaded drive, the invention provides that a wiper (9) is arranged in the second axial end region (7) of the threaded nut (4), which makes it more difficult for lubricant to escape from the threaded nut (4), wherein a collecting element (11) for receiving used lubricant is arranged at the second axial end region (7) of the threaded nut (4).