Spindle Device Unclamping Mechanism Integration
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Solution Overview
Problem
Conventional spindle devices have an increased overall length due to the unclamping device being arranged on the outer side, leading to higher moment loads and limited machining stability, especially in machine tools with inclined or swinging spindles.
Innovation Solution
The unclamping device is integrated within an annular space between the spindle and the draw bar, utilizing a piston driven by fluid pressure and supported by radial bearings, allowing for a compact structure and reduced overall length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the unclamping device is arranged on the outer side of the rear part of the spindle, then the unclamping function is achieved, but the overall length of the spindle device increases
Solution Approach 1:
The unclamping device is nested within the annular space between the spindle and draw bar, with the piston inserted through the draw bar's through-hole. This nesting arrangement allows the unclamping device to be housed inside the existing structural space rather than adding external components, thereby achieving the unclamping function while minimizing the overall length of the spindle device.
2Device complexity
If the overall length of the spindle device is increased, then the unclamping device can be accommodated, but the moment load on the support portion increases and machining stability is limited
Solution Approach 1:
Instead of arranging the unclamping device in the axial direction (length dimension), the invention utilizes the radial annular space between the spindle and draw bar. This dimensional shift from axial to radial arrangement allows the unclamping device to be accommodated without increasing the overall length, thereby maintaining short support spans and high machining stability.
3Length of moving object
If the unclamping device is integrated within the annular space between spindle and draw bar, then the overall length is shortened, but the structural complexity increases
Solution Approach 1:
The draw bar is designed with a through-hole that serves dual purposes: it allows the piston of the unclamping device to pass through and also serves as part of the clamping structure. This multi-functionality reduces the need for separate components and simplifies the overall structure despite the integrated arrangement of the unclamping device within the annular space.
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 shortens the spindle device, reducing moment loads and maintaining machining stability across various conditions, while allowing for precise machining with reduced deflection and expanded operational ranges.
Implementation Method 1
the unclamping device has a piston that moves the draw bar toward the front of the spindle by utilizing the fluid pressure
Implementation Method 2
the piston of the unclamping device is rotatably supported in the inner circumferential surface of the spindle by a first radial bearing
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Disclosed is a spindle device (5) for a machine tool such that draw bar (22) is inserted into spindle (20) which is rotatably supported in housing (12), and draw bar (22) is biased to a rear of spindle (20) by an elastic force of disc springs (23), resulting in tool holder (51) being clamped to spindle (20). Spindle device (5) is equipped with unclamping device (60) that comprises piston (63) which is provided in annular space (55) between spindle (20) and draw bar (22), and which, by means of fluid pressure, causes draw bar (22) to move toward the front of spindle (20) in resistance to the elastic force.