Ball Screw Inspection Jig for Post-Assembly Ball Count Verification
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Solution Overview
Problem
It is difficult to confirm the appropriate number of balls in the circulation path of a ball screw device after assembly, as the balls are not easily visible from the outside and may be incorrectly incorporated into the screw groove.
Innovation Solution
A method using an inspection jig with narrow and wide portions to determine the appropriate number of balls by inserting the jig between the balls in the circulation path, where the insertion state of the jig indicates whether the ball count is appropriate or not.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If balls are incorporated into the circulation path using assembly equipment, then the ball screw device can be assembled, but the number of balls may be excessively small or large and it is difficult to confirm the ball count after assembly
Solution Approach 1:
The inspection jig is designed with predetermined dimensions (narrow portion width, wide portion width) that correspond to specific ball count conditions. By preparing the inspection tool in advance with these predetermined characteristics, the inspection can be performed immediately after assembly without requiring complex measurement equipment or disassembly, thus achieving both ease of manufacture and measurement precision
2Volume of moving object
If the ball screw device is assembled in a compact structure, then the device size is reduced, but the balls become hardly visible from the outside for inspection
Solution Approach 1:
The inspection jig serves as an intermediary tool that accesses the hidden balls through the gap between the nut and screw shaft. Instead of trying to make the balls visible directly, the jig mediates the inspection process by being inserted through the existing gap and interacting with the balls indirectly through pushing and sensing their movement, thus solving the visibility problem without increasing device size
3Quantity of substance
If gaps between balls are reduced to maintain proper ball count, then the circulation path becomes more compact, but inspection difficulty increases
Solution Approach 1:
The inspection method utilizes the dynamic interaction between the inspection jig and the balls during insertion. The jig is pushed into the circulation path and the balls are dynamically displaced along the circulation path. By observing the dynamic response (how far the jig can be inserted, resistance encountered), the inspection can detect ball count conditions even when static gaps between balls are small
Data Source
AI summary
In inspecting the number of balls 30 disposed in circulation paths S1 to S3 of a ball screw device 1, an inspection jig 40 is inserted between the balls 30 disposed in the circulation paths S1 to S3 from a gap between a nut 10 and a screw shaft 20, and the number of the balls 30 is inspected by an insertion state of the inspection jig 40 at this time.