Multi-Spindle Screw Machine Upgrades for Independent Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mechanical-type multi-spindle screw machines, such as Davenport® machines, lack independent spindle assembly rotation, precise head positioning without expensive encoders, and zero-backlash tool slides, limiting their accuracy and performance compared to CNC machines.
Innovation Solution
The implementation of a multi-spindle machine tool design featuring independently rotating spindle assemblies driven by motors with ring gears, a low-cost sensor apparatus using proximity sensors for angular position determination, precise rolling-element bearings for head mounting, and zero-backlash tool slides with ball screws and linear rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mechanical-type multi-spindle screw machine uses a conventional design with a single motor driving all spindle assemblies through a gear train, then the device complexity is reduced and ease of manufacture is improved, but the productivity and adaptability are limited because all spindles must rotate at the same angular speed and cannot be independently controlled
Solution Approach 1:
The patent divides the spindle drive system into independent segments, with each spindle assembly having its own motor and ring gear. This segmentation allows each spindle to rotate at independently controlled angular speeds, enabling different machining operations to be performed simultaneously at different speeds, thereby improving productivity without requiring a complex centralized control system
Solution Approach 2:
The patent introduces dynamic control capabilities by equipping each spindle assembly with an independently controllable motor. This allows the rotational speed of each spindle to be dynamically adjusted according to the specific machining requirements at each station, enabling flexible adaptation to different workpiece types and operations while maintaining high productivity
2Measurement precision
If expensive encoder systems are used to determine the angular position of the head, then the measurement precision and manufacturing precision are improved, but the device complexity increases and the cost increases
Solution Approach 1:
The patent introduces an intermediary mechanical indexing mechanism with precisely spaced index positions that physically defines the angular positions of the head. This mechanical intermediary provides accurate angular position determination through its inherent geometric precision rather than requiring complex electronic sensors, thereby achieving high measurement precision while keeping the system relatively simple
Solution Approach 2:
The indexing mechanism serves its dual function of both driving the head to precise angular positions and simultaneously providing the reference for determining angular position. The same mechanical structure that performs the positioning action also provides the positional information, eliminating the need for separate expensive encoder systems
3Manufacturing precision
If conventional tool slides with mechanical backlash are used, then the ease of manufacture is improved and device complexity is reduced, but the manufacturing precision deteriorates due to backlash affecting tool position accuracy
Solution Approach 1:
The patent replaces conventional mechanical slide mechanisms with ball screw drives coupled with linear rails. The ball screw mechanism eliminates backlash through its precision ball recirculation system, providing accurate bidirectional tool positioning. This substitution maintains relative ease of manufacture using standard precision components while dramatically improving tool position accuracy for high-precision machining operations
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
Enables independent spindle rotation, precise head positioning, and zero-backlash tool movement, enhancing the accuracy and productivity of mechanical-type multi-spindle screw machines while reducing costs associated with encoder usage.
Implementation Method 1
The tool slide includes a ball screw arranged to be rotated by a motor and a linear rail having a stationary rail-like portion mounted on the machine frame and a movable portion guided by the rail-like portion and driven by the ball screw
Implementation Method 2
a linear rail having a stationary rail-like portion mounted on the machine frame and a movable portion guided by the rail-like portion and driven by the ball screw
Implementation Method 3
at least one rolling-element bearing acting between the member and frame such that the position of the member relative to the frame may be controlled at each of the index positions
Implementation Method 4
a low-cost sensor apparatus using proximity sensors for angular position determination
Data Source
AI summary
The present invention provides certain additional improvements for such mechanical-type multi-axis machine tools. These improvements include: (1) permitting the spindles to be rotated about their respective axes relative to the member independently of one another, (2) providing a low-cost, and yet highly-effective, sensor apparatus for determining the angular position of the member relative to the frame without the use of an expensive encoder or the like, (3) mounting the rotatable member more precisely relative to the frame, and (4) providing a zero-backlash tool slide on the frame for imparting an action to a workpiece.