Feed Screw Stage Mechanism for Backlash and Axial Play Control
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Solution Overview
Problem
Existing stage mechanisms face issues with large backlash, insufficient fixability, and increased size due to complex structures and protruding components, which hinder precision and compactness in positioning and moving workpieces.
Innovation Solution
A stage mechanism with a feed screw, a fixed stage incorporating the feed screw, a backlash absorbing portion, a deviation preventing portion, and a pressing force adjusting portion, which reduces backlash and play along the feed screw axis while allowing for a more compact design by using a cylindrical resin member and metal protective cover, and optimizing the contact surfaces for reduced friction and improved operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dovetail groove slide rail, slide fixing screw, and slide adjustment screw are used to fix the sliding part, then the fixability is improved, but the number of parts and structural complexity increase
Solution Approach 1:
The patent combines the fixing screw and adjustment screw into a single integrated screw structure. The screw has a fixing portion that engages with the fixed part and a pressing portion that presses against the sliding part, eliminating the need for separate fixing and adjustment components while maintaining both fixing and adjustment functions.
Solution Approach 2:
The integrated screw serves multiple functions: it acts as both a fixing mechanism (through the fixing portion engaging with the fixed part) and an adjustment mechanism (through the pressing portion contacting the sliding part). This multi-functional design reduces the number of parts while maintaining comprehensive functionality.
2Ease of operation
If machining shafts protrude to the outside of the stage to adjust position, then the position adjustment capability is improved, but the size of the stage increases
Solution Approach 1:
The screw structure is nested within the stage body. The fixing portion is embedded in the fixed part while the pressing portion extends to contact the sliding part, allowing the adjustment mechanism to be contained within the stage boundaries rather than protruding outward.
Solution Approach 2:
The adjustment mechanism operates in the internal space of the stage rather than requiring external protrusions. The screw rotates within the stage body, converting rotational motion into linear motion of the sliding part through the pressing portion, eliminating the need for external machining shafts.
3Volume of moving object
If a compact design is pursued to reduce size, then the volume is reduced, but backlash and play in the feed screw direction increase
Solution Approach 1:
The patent optimizes the geometric parameters of the integrated screw, including the thread pitch, the shape and size of the fixing portion, and the contact surface geometry of the pressing portion. These parameter optimizations reduce backlash and play while maintaining a compact overall size.
Solution Approach 2:
The pressing portion of the screw features a specifically designed contact surface that concentrates the pressing force on a localized area of the sliding part. This localized quality enhancement reduces play and improves precision in the feed screw direction without requiring an overall increase in size.
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 effectively minimizes backlash and play, enhances fixability, and reduces the overall size of the stage mechanism, enabling precise and stable positioning with improved operability and durability over time.
Implementation Method 1
a feed screw 11, a fixed stage 13 having a space portion 13a incorporating the feed screw 11, a movable stage 15 performing a predetermined movement in response to a rotational motion of the feed screw 11
Implementation Method 2
a backlash absorbing portion 17 preventing backlash of the feed screw 11
Implementation Method 3
a deviation preventing portion 19 provided in the vicinity of a first end portion 11d as one end of the feed screw 11, in contact with a wall 13b of the space portion 13a, and preventing the feed screw from deviating in a direction toward the first end portion 11d
Implementation Method 4
a pressing force adjusting portion 21 having an end contact with a second end portion 11e as the other end of the feed screw 11 and adjusting a pressing force by which the feed screw 11 is pressed in a direction from the second end portion 11e side to the first end portion 11d
Data Source
AI summary
A stage mechanism includes a feed screw, a fixed stage having a space portion incorporating the feed screw, a movable stage, and a backlash absorbing portion. The feed screw has a first end portion and a second end portion. The stage mechanism further includes a deviation preventing portion preventing the feed screw from deviating in a direction toward the first end portion and a pressing force adjusting portion 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 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.