Nut-Rotating Ball Screw Feed With Compact Bearing Layout
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Solution Overview
Problem
Existing ball screw driving devices in numerical control machine tools are large, costly, and inefficient due to high inertia, requiring high-power motors and increased size and weight, which also hampers heat dissipation and service life.
Innovation Solution
A high-speed nut rotation feed ball screw device that directly drives the ball screw nut using a low-power driving motor, with a compact bearing unit arranged axially along the ball screw to reduce size and enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a ball screw is used to drive the feed movement, then the feed drive function is achieved, but the large size and mass of the ball screw increases inertia and requires high-power motors
Solution Approach 1:
Instead of rotating the ball screw to drive the nut linearly, the invention inverts the mechanism by rotating the ball screw nut while the ball screw remains stationary. This inversion allows the lightweight nut to rotate instead of the heavy ball screw, dramatically reducing the moment of inertia and enabling the use of low-power motors while achieving the same feed drive function.
Solution Approach 2:
The invention extracts the rotational function from the ball screw and transfers it to the ball screw nut. By making the nut the rotating component and the ball screw the stationary guide, the system separates the functions of motion generation (rotation of nut) and motion guidance (ball screw geometry), reducing the mass that needs to be accelerated.
2Reliability
If a bearing unit is sleeved outside the ball screw nut, then the nut is supported, but the radial size of the ball screw nut assembly increases
Solution Approach 1:
The bearing unit is nested inside the ball screw nut rather than being sleeved outside. The inner bearing fixing sleeve contains the bearing assembly, which is installed in the bearing installation space formed between the inner and outer bearing fixing sleeves. This nested arrangement allows the bearings to be housed within the nut's internal structure, reducing the overall radial dimensions while maintaining support functionality.
3Reliability
If the bearing unit is sleeved outside the ball screw nut, then the nut is supported, but heat generated between the ball screw nut and ball screw is not easily dissipated
Solution Approach 1:
The nested bearing arrangement creates internal spaces within the ball screw nut that facilitate heat dissipation. The bearing installation space between the inner and outer bearing fixing sleeves, along with the internal structure of the nested bearings, provides pathways for heat to escape from the contact interface between the ball screw and nut, improving thermal management.
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
The solution reduces the size and cost of the ball screw device, enables high-speed rotation of the ball screw nut, and improves heat dissipation and service life by minimizing inertia and optimizing the arrangement of the ball screw nut and bearing unit.
Implementation Method 1
the first pulley and the second pulley are connected via the synchronous belt
Data Source
AI summary
A high-speed nut rotation feed ball screw device includes a ball screw, a ball screw nut, a bearing unit, and a driving unit. The ball screw is fixed on a machine tool via a ball screw seat. The bearing unit includes an inner bearing fixing sleeve, an outer bearing fixing sleeve, and a bearing assembly. One end of the inner bearing fixing sleeve is fixedly connected to one end of the ball screw nut, and another end is fixedly connected to the driving unit. The ball screw nut is arranged on the ball screw. The driving unit includes a first pulley, a second pulley, a synchronous belt, and a driving motor. The first pulley is connected to the driving motor. The second pulley is sleeved on the ball screw and is connected to the inner bearing fixing sleeve. The first and second pulleys are connected via the synchronous belt.