Ball Screw Nut Circulation Structure Without Pin Fastening
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Solution Overview
Problem
The existing ball screw devices require a pin to fix the circulation component, increasing the number of components and limiting the layout due to the need for through holes in the nut main body and circulation component.
Innovation Solution
A nut design that eliminates the need for a pin by using a caulking mechanism with ribs and recessed parts to securely attach the circulation component, ensuring it remains attached without detaching from the nut main body, even under load, using a configuration of inner and outer peripheral side components with arm parts and a tangential ball passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin is used to fix the circulation component, then the circulation component is securely attached to the nut main body, but the number of components increases and the layout is limited due to through holes
Solution Approach 1:
The fixing function is merged into the circulation component itself through the rib structure that protrudes from the circulation component and engages with the nut main body. This eliminates the need for a separate pin component while maintaining secure attachment.
Solution Approach 2:
The pin component is extracted/removed from the system entirely. Instead of using a separate pin to fix the circulation component, the design uses an integrated rib structure that performs the same fixing function without requiring additional components or through holes.
2Ease of manufacture
If through holes are created in the nut main body and circulation component for pin insertion, then the circulation component can be fixed, but the layout is limited and manufacturing complexity increases
Solution Approach 1:
The fixing structure is merged into the circulation component as an integrated rib structure. This eliminates the need for separate through holes in both the nut main body and circulation component, simplifying the overall structure and improving manufacturing flexibility.
Solution Approach 2:
Instead of creating through holes to insert a pin for fixing, the design inverts the approach by having the circulation component itself provide the fixing structure through protruding ribs that engage with the nut main body without requiring through holes.
3Strength
If the circulation component is divided into inner and outer peripheral side components, then the tongue strength is maintained for scooping balls, but the component assembly becomes more complex
Solution Approach 1:
The circulation component is segmented into an inner peripheral side component and an outer peripheral side component along a division surface. This segmentation allows the tongue to be formed as a single integral structure within the inner peripheral side component, maintaining its strength for scooping balls while allowing the overall circulation component to be manufactured and assembled in parts.
Data Source
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AI summary
To provide a nut that can suppress increase in the number of components. The nut according to the present disclosure includes a nut main body and a circulation component. The nut main body includes a housing part having a bow shape when viewed from an axial direction, a seat surface, a through hole, and a pair of side surfaces. The circulation component includes a circulation component main body, two arm parts extending toward both sides in a seat surface direction from the circulation component main body, ribs projecting from the respective two arm parts, and caulking parts obtained by caulking the ribs. Recessed parts that the caulking parts enter are disposed on the pair of side surfaces. A ball passage is disposed in the circulation component main body. The circulation component is obtained by joining an inner peripheral side component to an outer peripheral side component that are divided along the ball passage when viewed from the axial direction. The inner peripheral side component includes a tongue that scoops up the ball, an inner peripheral side rolling surface surrounding an inner peripheral side of the ball passage, and one of the two arm parts. The outer peripheral side component includes an outer peripheral side rolling surface surrounding an outer peripheral side of the ball passage, and the other one of the two arm parts.