Machine Tool Spindle Coupling for Differential-Speed Tool Adjustment
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Solution Overview
Problem
Existing spindle assemblies for machine tools have complex designs that compromise either efficiency, effectiveness, or accuracy during radial adjustment of cutting tools, leading to undesirable vibrations and limited functionality, especially when trying to use flexible machining centers for multiple purposes.
Innovation Solution
A spindle assembly with a coupling mechanism that allows for differential speed between the machine tool spindle and a rotatable shaft, enabling radial adjustment of tools through a combination of gears and a second rotary drive, which can be retrofitted to standard spindles for enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a radial adjustment device with parallel spring arrangement and cone part is used, then the tool can be radially adjusted, but the design becomes complicated and rigidity is compromised leading to vibrations
Solution Approach 1:
The invention extracts the adjustment mechanism from the traditional complex design with parallel springs and cone parts, replacing it with a simplified wedge-shaped element that directly converts rotational movement into radial adjustment. This removes unnecessary components while maintaining the adjustment function.
Solution Approach 2:
The wedge-shaped adjustment element acts as an intermediary between the rotational drive and the tool holder, converting rotational movement into precise radial adjustment through its inclined surface, eliminating the need for complex spring arrangements and cone parts.
2Adaptability or versatility
If a complex adjustment mechanism is used to enable radial adjustment during machining, then tool flexibility is improved, but structural rigidity decreases causing undesirable vibrations
Solution Approach 1:
The invention implements a dynamic adjustment mechanism where the wedge-shaped element can be rotated during machining to change the tool's radial position in real-time, enabling flexible control while maintaining structural rigidity through the simple, solid wedge design rather than complex flexible mechanisms.
3Ease of operation
If a planetary gearbox with differential speed is used for angular adjustment, then radial adjustment during rotation is achieved, but the structure becomes complex and functionality is limited
Solution Approach 1:
The invention replaces the complex planetary gearbox mechanism with a simpler direct rotational drive of the wedge-shaped element, achieving the same angular adjustment function through a more straightforward mechanical approach that allows easier retrofitting and greater versatility.
4Measurement precision
If a rigid core with elastically deflectable head is used, then tool positioning is achieved, but the design is complicated and does not guarantee sufficient rigidity
Solution Approach 1:
The invention segments the tool holder into distinct functional zones: a rigid core portion for structural stability and a wedge-adjustable section for precise radial positioning. This segmentation allows each part to optimize its function while maintaining overall simplicity and rigidity.
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 simple, rigid, and flexible structure for radial tool adjustment, allowing standard spindles to perform all machining processes and support both non-controllable and controllable tools, enhancing the versatility and efficiency of machining centers.
Implementation Method 1
The planetary carrier of a planetary gearbox does not rotate. The solar wheel drives over the planetary wheels the hollow wheel, which circulates in the opposite direction. The hollow wheel, taken in the same direction, now drives the solar wheel via the planetary wheels.
Implementation Method 2
as soon as the actuator adjusts the planetary carrier in the direction of rotation, this angular adjustment movement is superimposed on the rotary movement of the planar pull shaft, so that it experiences an angular adjustment against the spindle with a slightly changed rotational speed
Implementation Method 3
the centre of gravity of the tool carrier is offset from the axis of rotation so that the centrifugal forces occurring during rotation of the drill head press the tool carrier against the sliding body
Data Source
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AI summary
The invention relates to a spindle assembly (S) for a machine tool with a machine tool spindle (1) which can be set into rotation by means of a first rotary drive (3) and in which an internal shaft (2) rotatably mounted relative to the machine tool spindle (1) is arranged, wherein the spindle assembly (S) is combined according to the invention with a coupling assembly (6) which has an axially displaceable first gear (Z1) and a second rotary drive (5), wherein the first gear (Z1) engages the machine tool spindle (1) with the shaft (2) in a first end position such that the machine tool spindle (1) and the shaft (2) rotate at the same speed and wherein the first gear (Z1) couples the shaft (2) with the second rotary drive (5) in a second end position, wherein a rotational speed can be transmitted to the shaft (2) by the second rotary drive (5).which differs from the speed of the machine tool spindle (1) so that a controllable tool held in the spindle assembly (S) can be radially adjusted by a differential speed between the machine tool spindle (1) and the shaft (2) rotatably mounted in it.