Stationary Drive Spindles for Machine Tool Positioning Accuracy
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Solution Overview
Problem
Existing machine tools for sheet metal working require high positioning accuracy of drive devices to ensure trouble-free machining, but they face challenges in maintaining accuracy due to inertia-related impairments during longitudinal movements of spindle nuts, which affects the precision and efficiency of the machining process.
Innovation Solution
A compact drive device with two stationary drive spindles, each with a spindle nut that moves longitudinally, where both spindles are of the same length and identical in torsional and axial rigidity, allowing for uniform drive behavior and minimizing the mass moved during longitudinal movements, thus reducing inertia-related impairments and maintaining equidistance with fixed bearings for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drive motors are integrated with spindle nuts to enable longitudinal movements, then the spindle nuts can be moved along the drive spindles, but the mass to be moved increases significantly, causing inertia-related impairments to positioning accuracy
Solution Approach 1:
The system is segmented into stationary drive spindles and movable spindle nuts, where the drive function is separated from the moving mass. The drive spindles remain stationary while only the compact spindle nuts move, significantly reducing the moved mass compared to integrated drive motors.
Solution Approach 2:
Instead of making the spindle nuts stationary with moving drive motors, the invention inverts the approach by making the drive spindles stationary and the spindle nuts movable. This inversion dramatically reduces the mass that needs to be accelerated during positioning operations.
2Adaptability or versatility
If two drive spindles have different lengths or structural properties, then the drive device can be more compact or adaptable, but the drive behavior becomes non-uniform, impairing synchronization of spindle nut movements
Solution Approach 1:
The invention applies local quality by making the drive spindles structurally identical in critical regions (same length, same torsional rigidity, same axial rigidity) to ensure uniform drive behavior, while allowing other parts of the machine tool to vary for compactness and adaptability.
Solution Approach 2:
The two drive spindles are designed with homogeneous structural properties including equal length, equal torsional rigidity, and equal axial rigidity. This homogeneity ensures that both spindles exhibit identical drive behavior under the same operating conditions, enabling precise synchronization of the spindle nuts.
3Area of stationary object
If the spindle nuts are positioned close together or overlapping in the transverse direction, then the drive device becomes more compact, but the fixed bearings must be precisely positioned to maintain equidistance for accurate synchronization
Solution Approach 1:
The invention resolves the spacing conflict by transitioning to another dimension - using longitudinal positioning relative to the fixed bearings rather than transverse spacing. The spindle nuts can be closely spaced or overlapping in the transverse direction while maintaining accurate synchronization through their longitudinal positions on the drive spindles.
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 design enhances the positioning accuracy and efficiency of the machining tool by ensuring uniform drive behavior and minimizing the impact of inertia, allowing for precise and reliable longitudinal movements without the need for drive motors to move with the spindle nuts, thereby improving the overall machining process.
Implementation Method 1
A fixed bearing at one longitudinal end of each drive spindle supports it in the longitudinal direction of the drive spindle
Implementation Method 2
can be rotated about a spindle axis by means of a drive
Implementation Method 3
spindle nuts, which are seated on each of the drive spindles and are fastened by means of the spindle arrangement, are movable simultaneously with longitudinal movements in the longitudinal direction of the drive spindles by each of the spindle nuts being movable by means of the associated drive spindle with a longitudinal movement
Data Source
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AI summary
A drive device (22) for a machine tool comprises two parallel drive spindles (23, 24) of at least equal length and identical in terms of their torsional and axial stiffness. Each spindle is rotatably mounted about a spindle axis (25, 26) and can be driven about its respective axis. Each drive spindle (23, 24) has a fixed bearing (27, 29) at one end, acting in its longitudinal direction. Spindle nuts (42, 43) mounted on the drive spindles (23, 24) are movable simultaneously with longitudinal movements in the longitudinal direction of the drive spindles (23, 24). A machine tool is equipped with a drive device (22) of the type described.