Electric Motor Clamping Device for Machine Tools

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Solution Overview

Problem

Existing processing machines face challenges with secure and precise clamping of workpieces and tools due to the high forces and rotational movements involved, which are difficult to manage with hydraulic systems, leading to maintenance issues and limited flexibility.

Innovation Solution

The use of an electric motor, specifically a sensorless permanent magnet excited synchronous motor, to actuate the clamping device, allowing for direct or indirect clamping of workpieces and tools, and enabling the potential elimination of hydraulic systems by decentralizing the hydraulic pump for specific applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If hydraulic clamping devices are used to achieve high clamping forces, then the clamping force is sufficient, but the system becomes maintenance-prone and complex due to high-pressure hydraulic lines

Engineering Contradiction:
Improveclamping forceVSAvoidhydraulic system complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic mechanical system with an electric motor-driven clamping mechanism. The electric motor directly generates the clamping force through a clamping element, eliminating the need for hydraulic pumps, high-pressure lines, and associated control valves. This substitution reduces maintenance requirements while maintaining the necessary clamping force for securing workpieces and tools.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts and removes the hydraulic system components (pump, high-pressure lines, valves) from the clamping mechanism, retaining only the essential clamping function. By separating the force generation (electric motor) from the clamping action, the system achieves simplicity while maintaining effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If hydraulic lines are made flexible to accommodate workpiece table movements and rotations, then positional flexibility is improved, but the system becomes more maintenance-prone and complex

Engineering Contradiction:
Improveflexibility for movementsVSAvoidmaintenance requirements
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The electric motor-driven clamping element replaces the flexible hydraulic lines entirely. Since the electric motor is directly mounted on the workpiece table or tool holder, it moves with the table or tool without requiring flexible connections. This eliminates the reliability issues associated with flexible hydraulic lines while maintaining full adaptability to movements and rotations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Force

If hydraulic systems are used for both workpiece and tool clamping, then high forces can be achieved, but the equipment outlay and installation costs are considerable

Engineering Contradiction:
Improveclamping forceVSAvoidinstallation costs
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive hydraulic infrastructure (pump unit, valves, piping, hose laying) with relatively simple electric motors and control electronics. The electric motors can be directly mounted and wired, eliminating the need for complex hydraulic installation while providing equivalent or superior clamping force.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electric motor system serves multiple functions: it provides clamping force for both workpieces and tools, and can potentially serve as a drive mechanism for the workpiece table or tool holder. This multi-functionality reduces the overall equipment outlay compared to dedicated hydraulic systems for each function.

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

4Manufacturing precision

If hydraulic clamping is used to ensure secure fixation, then positional accuracy is maintained, but the system becomes less adaptable to different processing operations

Engineering Contradiction:
Improvepositioning accuracyVSAvoidflexibility for processing operations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The electric motor-driven clamping element can dynamically adjust its position and force application point, allowing it to accommodate different workpiece sizes, shapes, and clamping requirements. The motor can be precisely controlled to maintain positioning accuracy while adapting to various processing operations, unlike fixed hydraulic line configurations.

Inventive Principle:
Principle #15Dynamics

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 solution provides a more flexible, efficient, and maintenance-friendly clamping system that can handle high forces and rotational movements, reducing the need for complex hydraulic setups and improving the versatility of processing machines by enabling turning operations and reducing installation costs and environmental impact.

Implementation Method 1

an electric motor for generating the clamping force is provided, designed as a sensorless and permanent magnet excited synchronous motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2363235B1Machining unit
Publication Date: 2014.04.16 GROB WERKE & K G
  • EP2363235B1 patent drawingFigure 1
  • EP2363235B1 patent drawingFigure 2a~2b
  • EP2363235B1 patent drawingFigure 3

AI summary

The invention relates to a machine tool for machining one or more workpieces, wherein the workpiece is held in the machine tool on or against a workpiece table that is not rotatable or, in particular, rotatable about at least one axis, either directly or indirectly by a clamping device. The invention is characterized in that the clamping device comprises at least one clamping element which interacts directly or indirectly with the workpiece and an electric motor is provided for generating the clamping force, the operative connection of which is with the clamping element.