Tie Rod Flange Fixing Unit for Agitator Ball Mill

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Solution Overview

Problem

The existing methods for attaching the agitator shaft to the drive shaft in agitator ball mills are difficult to dismantle, often requiring mechanical stress that can damage the components and involve complex procedures due to tightened threaded connections and contamination issues.

Innovation Solution

A fastening unit with a tie rod and flange connection that allows for a detachable and secure attachment of the agitator shaft to the drive shaft, using a screw connection and flange design to prevent axial movement and facilitate easy disassembly without mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tie rod is tightly screwed into the internal thread of the agitator shaft to secure the attachment, then the connection strength is improved, but the disassembly process becomes difficult and requires mechanical stress that can damage the components

Engineering Contradiction:
Improveconnection strengthVSAvoiddisassembly ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The fastening system is divided into modular components: the drive shaft with external thread, the agitator shaft with internal thread, and the tie rod as a separate fastening element. This segmentation allows the tie rod to be independently removed from either the drive shaft or agitator shaft, enabling disassembly without applying mechanical stress to the threaded connections, thus resolving the contradiction between strong attachment and easy disassembly

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tie rod acts as an intermediary element between the drive shaft and agitator shaft. It provides the securing function while being designed to facilitate controlled disassembly. The tie rod's structure with head and threaded portion allows it to mediate the connection in a way that prioritizes both strength and ease of maintenance, eliminating the need for hammering or forceful separation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the tie rod is used to brace the agitator shaft with the drive shaft to prevent axial movement, then the reliability of the connection is improved, but the disassembly process requires partial unscrewing and hammering that can damage the threads

Engineering Contradiction:
Improveconnection reliabilityVSAvoidthread damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of designing a system where the agitator shaft is screwed into the drive shaft (direct threading), the invention inverts the approach by using a tie rod that threads onto either component and braces against the other. This inversion allows the fastening function to be separated from the structural components, enabling reliable connection while avoiding thread damage during disassembly, as the tie rod can be unscrewed from one side without stressing the other threaded connection

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The tie rod is designed as a sacrificial or easily replaceable fastening element. If thread damage occurs, the tie rod can be replaced without damaging the more valuable agitator shaft or drive shaft threads. This approach prioritizes the longevity of the main components while using a simpler, less critical element for the fastening function

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If the tie rod is designed as a tube to cool the agitator shaft, then the cooling function is added, but the disassembly process remains difficult and requires mechanical stress

Engineering Contradiction:
Improvecooling functionVSAvoiddisassembly ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The tie rod is designed with multi-functionality: it provides mechanical fastening through threading, structural bracing to prevent axial movement, and thermal cooling through its tubular structure with internal passage. By combining these functions in a single element, the invention adds cooling capability without compromising disassembly ease, as the unified structure allows removal from one side without affecting the other functions or requiring mechanical stress

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3085447B1Fixing unit for an agitator ball mill, agitator ball mill and a method for releasing a fixing unit
Publication Date: 2018.10.24 NETZSCH FEINMAHL TECHNIK GMBH
  • EP3085447B1 patent drawingFigure 1A~1B
  • EP3085447B1 patent drawingFigure 2A~2B
  • EP3085447B1 patent drawingFigure 3A~3B

AI summary

The invention relates to a fastening unit for a stirred ball mill. The fastening unit comprises a drive shaft (60, 110) of the stirred ball mill, a stirring shaft (51, 101) of the stirred ball mill, and a tie rod (70, 120). A free end (55, 105) of the stirring shaft (51, 101) is positively and/or frictionally connected to a first free end (61, 111) of the drive shaft (60, 110), so that an operative connection exists between the stirring shaft (51, 101) and the drive shaft (60, 110). The drive shaft (60, 110) is a hollow shaft with a continuous cavity (64, 114) along a longitudinal axis (X60, X110) of the drive shaft (60, 110).Within the cavity (64, 114) of the drive shaft (60, 110) the tie rod (70, 120) is guided, which has a first connecting element (72, 122) at a first free end (71, 121) and a head (74, 124) at the opposite second free end (73, 123), wherein the first connecting element (72, 122) of the tie rod (70, 120) forms a positive and force-locking connection with a correspondingly designed second connecting element (57, 107) at the free end (55, 105) of the agitator shaft (51, 101) arranged on the drive shaft (60, 110). The head (74, 124) of the tie rod (70, 120) projects at least partially beyond the second free end (65, 115) of the drive shaft (60, 110). According to the invention, the tie rod (70, 120) can be fixed to the drive shaft (60, 110) by means of a flange connection (84, 135). The invention further relates to a stirred ball mill and a method for releasing a fastening unit of a stirred ball mill.