Thread-Forming Spindle Geartrain for High-Speed Synchronized Tapping
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Solution Overview
Problem
Conventional machine tools are limited by synchronization speed between rotary and axial movements of the tool spindle, restricting the maximum rotational speed of the thread production tool and resulting in inefficient thread production, which affects cycle times and economic efficiency.
Innovation Solution
A transmission gear is introduced between the tool spindle and the thread-forming tool, increasing rotational speed by translating the tool spindle's rotation into higher speed for the thread-forming tool, along with an elastic element to compensate for measurement errors and synchronization errors, and a torque arm to support torques in both directions of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tool spindle rotational speed is increased to improve thread production speed, then productivity increases, but synchronization between rotary movement and axial feed becomes impossible beyond a certain speed limit
Solution Approach 1:
The transmission system is segmented into multiple independent components: the tool spindle rotating at a lower speed, the planetary gear set providing speed multiplication, and the thread-forming tool rotating at the higher required speed. This segmentation allows each component to operate within its optimal speed range while maintaining synchronization through mechanical coupling.
Solution Approach 2:
The planetary gear set acts as an intermediary mechanism between the tool spindle and the thread-forming tool. It translates the lower rotational speed of the tool spindle into the higher rotational speed required by the thread-forming tool while maintaining precise synchronization through its inherent mechanical gear ratio, eliminating the synchronization problems that would occur at high speeds direct-coupled.
2Productivity
If a transmission gear is introduced to increase rotational speed, then thread production speed increases, but device complexity increases
Solution Approach 1:
The planetary gear set combines multiple gear elements (sun gear, planet gears, ring gear) into a single integrated transmission unit that fits within the existing tool spindle structure. This merging approach achieves high speed multiplication in a compact form factor, minimizing the increase in device complexity while maximizing productivity improvement.
Solution Approach 2:
The planetary gear arrangement utilizes radial space around the tool spindle axis to accommodate multiple planet gears simultaneously, rather than requiring a long axial extension. This dimensional arrangement compactly packs the transmission components, reducing overall system complexity while achieving the required speed multiplication.
3Ease of operation
If the tool spindle speed is limited by synchronization constraints, then measurement and control remain simple, but cycle time increases reducing economic efficiency
Solution Approach 1:
The system replaces the direct mechanical coupling between tool spindle and thread-forming tool with a planetary gear transmission. This substitution allows the tool spindle to rotate at lower speeds where simple synchronization control is sufficient, while the gear mechanism handles the speed multiplication, thereby reducing cycle time without complicating the control system.
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 allows for higher thread production speeds, improving cycle times and economic efficiency by overcoming the limitations of synchronization speed, while maintaining accurate measurement and synchronization.
Implementation Method 1
a transmission gear (6) arranged between the tool spindle (3) and the thread-forming tool (2), stationary in both directions of rotation and displaceable in the axial direction in relation to the rotary speed (ω 2 ) of the tool spindle (3) translated into high speed
Implementation Method 2
a coolant channel (39) runs centrally through the tool spindle (3) towards the tool holder (15), which is in the area of the transmission gear (6) is guided in a coolant tube (40)
Implementation Method 3
an elastic element to compensate for measurement errors and synchronization errors
Data Source
Figure 1
Figure 2~3
Figure 4~8
AI summary
The invention relates to a method for generating a thread on a numerically controlled machine tool (1) with a thread generating tool (2), the thread generating tool (2) being rotated by a tool spindle (3) and simultaneously being advanced in the axial direction (A) in accordance with the thread pitch to produce a thread in a bore (4) of a workpiece (5). In order to increase the working speed of the thread production, the invention provides that the rotational speed (ω1) of the thread production tool (2) is increased by means of a transmission gear (6) effectively arranged between the tool spindle (3) and the thread production tool (2) in relation to the rotational speed (ω2) of the tool spindle (3) is translated into fast. The invention also relates to a numerically controlled machine tool and a coupling device with a transmission gear (6).