Modular Spindle Unit with Coaxial Axial Actuation

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Solution Overview

Problem

Existing multi-spindle machining heads face challenges such as high costs, limited flexibility, and reduced packing density due to complex torque transmission and axial adjustment mechanisms, which restrict their ability to perform diverse machining operations efficiently.

Innovation Solution

A modular spindle unit design where the drive motor is axially displaceable within the module housing, eliminating the need for costly torque transmission and allowing for compact, easily assembled spindle units with independent rotational control of each spindle, enabling a wide range of machining functions like horizontal drilling and milling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If axial adjustment drives are arranged offset parallel to the individual spindle units, then the spindle units can be adjusted axially, but the spindle units cannot be arranged close to the module carrier and drilling patterns with very small drilling spindle distances cannot be realized

Engineering Contradiction:
Improveaxial adjustment capabilityVSAvoidpacking density of spindle units
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent moves the axial adjustment mechanism from a parallel offset arrangement to a coaxial arrangement along the spindle axis. This dimensional repositioning allows the adjustment drives to be integrated within the spindle unit's central axis, eliminating the need for lateral space and enabling compact packing of spindle units on the module carrier while maintaining full axial adjustment capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The axial adjustment drives are nested within the coaxial structure of the spindle units, with the adjustment mechanism integrated inside the spindle assembly rather than positioned externally. This nesting approach minimizes the overall footprint and allows spindle units to be arranged with very small center distances.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If polygonal toothing is used for torque transmission between drive motor and drive spindle, then axial adjustment can be carried out, but the diameter of the spindle unit is greatly increased and packing density is reduced

Engineering Contradiction:
Improveaxial adjustment capabilityVSAvoiddiameter of spindle unit
Core Design Contradiction:
Ease of operationVSArea of moving object

Solution Approach 1:

The patent extracts the complex polygonal toothing mechanism from the torque transmission path and replaces it with a simpler direct drive or alternative transmission mechanism. This removal of the bulky polygonal gearing eliminates the need for large diameter components while preserving the axial adjustment function through a more compact design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the mechanical polygonal toothing system with an alternative mechanism such as a rack and pinion, lead screw, or direct motor coupling. This substitution eliminates the need for complex meshing gears that increase spindle diameter, achieving the same axial adjustment function with a compact structure that maintains high packing density.

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

3Productivity

If gear train is used to drive individual spindles, then multiple spindles can be driven by a central motor, but the individual work spindles cannot be driven individually and the gear drive causes considerable wear and tear

Engineering Contradiction:
Improvemulti-spindle operation capabilityVSAvoidindependent spindle control
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the drive system by providing each spindle with its own independent drive motor rather than using a single central motor with a gear train. This segmentation enables each spindle to be controlled independently for different directions of rotation, processing capacities, and sensor integration, while eliminating the wear and tear associated with mechanical gear connections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universal independent drive capability for each spindle, allowing every spindle to perform multiple functions including different rotation directions, variable speeds, and integration of various sensors. This multi-functionality is achieved through individual motor control, replacing the limited capabilities of a shared gear-driven system.

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

Data Source

PatentEP2178684B1Modular spindle unit
Publication Date: 2012.10.03 WITTENSTEIN GMBH & CO KG
  • EP2178684B1 patent drawingFigure 1
  • EP2178684B1 patent drawingFigure 2
  • EP2178684B1 patent drawingFigure 3

AI summary

The invention relates to a modular spindle unit for forming a multispindle machining head (36, 47, 49) for a machine tool, wherein the spindle unit (01, 30, 54) comprises at least one drive spindle (02) to which a tool (37) or tool carrier (51, 52) can be attached, and wherein the spindle unit (01, 30, 54) comprises a module housing (08, 31) in which the drive spindle (02) is mounted such that it can rotate freely and be axially displaced. Together with further module housings (08, 31), the module housing (08, 31) can be fastened to the machining head (36, 47, 49), wherein the spindle unit (01, 30, 54) comprises at least one drive motor (03) which can be used to drive an associated drive spindle (02) in rotation, and wherein the centre axis of the drive motor (03) and the centre axis of the drive spindle (02) run coaxially and define a centre axis (07) of the unit. The spindle unit (01, 30, 54) comprises at least one axial actuating device (05) which can be used to axially drive an associated drive spindle (02) in the direction of the centre axis (07) of the unit, wherein the centre axis of at least one axial actuating device (05) and the centre axis (07) of the unit run coaxially. The drive motor (03) is mounted in the module housing (08, 31) such that it can be displaced axially, and may be axially displaced in the module housing (08, 31) by the axial actuating device (05), together with the drive spindle (02), being driven along the centre axis (07) of the unit.