Feed Screw Stage Mechanism With Axial Backlash Absorption
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Solution Overview
Problem
Existing stage mechanisms face issues with large backlash and insufficient fixability due to increased structural complexity, size, and operability challenges, particularly with feed screws that protrude and are heavy, leading to reduced precision and increased size.
Innovation Solution
A stage mechanism with a feed screw, a fixed stage incorporating a space portion, a backlash absorbing portion, a deviation preventing portion, and a pressing force adjusting portion, which includes a cylindrical resin member and a metal protective cover, reduces backlash and play, and allows for compact design and improved operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a feed screw protrudes from the fixed stage for operation, then the stage mechanism can be operated to adjust position, but the overall size increases and precision decreases due to larger backlash and play
Solution Approach 1:
The feed screw is nested within a recess formed in the fixed stage, with the end surface of the feed screw abutting against the bottom surface of the recess. This nesting arrangement allows the feed screw to be operated while minimizing its protrusion, thereby reducing overall size and minimizing backlash and play between the feed screw and fixed stage, which improves positioning precision.
Solution Approach 2:
A elastic member is interposed between the end surface of the feed screw and the bottom surface of the recess, providing periodic elastic deformation. This elastic action absorbs gaps and reduces backlash dynamically during operation, maintaining precision while allowing continuous adjustment movement.
2Stability of the object's composition
If the feed screw is made heavier for stability, then the stage mechanism is more stable during operation, but the overall size and weight increase
Solution Approach 1:
The elastic member acts as a counterbalancing element, providing an elastic force that compensates for the weight and惯性 of the feed screw. This allows the feed screw to be lighter while maintaining operational stability through the elastic support and damping effects during positioning adjustments.
3Ease of operation
If the feed screw protrudes more to improve operability, then it is easier to operate the stage mechanism, but the size of the stage mechanism increases
Solution Approach 1:
The feed screw is nested within a recess in the fixed stage, allowing adequate length for operation while minimizing external protrusion. This enables operators to access and turn the feed screw effectively without increasing the overall length or external dimensions of the fixed stage.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Provided is a compact stage mechanism entailing little backlash and little play in a direction along the axis of a feed screw. A stage mechanism 10 includes a feed screw 11, a fixed stage 13 having a space portion 13a incorporating the feed screw, a movable stage 15, and a backlash absorbing portion 17. The feed screw has a first end portion 11d and a second end portion 11e. The stage mechanism further includes a deviation preventing portion 19 preventing the feed screw from deviating in a direction toward the first end portion and a pressing force adjusting portion 21 adjusting the pressing force by which the feed screw is pressed in a direction from the second end portion side to the first end portion. The deviation preventing portion is in contact with a wall 13b of the space portion on the first end portion side. The pressing force adjusting portion is in line contact with and presses the second end portion.