Riveted Ball Nut Structure for Compact Bearing Fixation
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Solution Overview
Problem
The use of nuts as fixing means in conventional ball nuts is space-consuming, increases manufacturing complexity and cost, and prolongs the process.
Innovation Solution
A mechanical actuator design that eliminates the need for nuts by using a hardened inner ball nut with a malleable outer part and a riveting area, allowing the bearing to be riveted directly to the outer part, thereby simplifying the manufacturing process and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nut is used as fixing means on the ball nut, then the bearing can be fixed to the outer surface, but the space consumption and manufacturing complexity increase
Solution Approach 1:
The invention extracts and eliminates the nut component from the fixing system. Instead of using a separate nut on an external threaded surface, the threading is integrated directly into the ball nut body, and the bearing is fixed by pressing the outer contour of the ball nut against the inner contour of the bearing housing, removing the need for separate fixing means.
Solution Approach 2:
The invention merges the fixing function into the ball nut structure itself. The threaded surface is integrated into the body of the ball nut rather than being a separate component, and the bearing fixation is achieved through the geometric configuration of the ball nut's outer surface engaging with the bearing housing, combining structure and fixation function.
2Reliability
If a nut is used as fixing means on the ball nut, then the bearing can be fixed to the outer surface, but the manufacturing time and cost increase
Solution Approach 1:
The invention removes the nut component and the associated threading operation from the manufacturing process. The bearing is fixed directly through the ball nut's outer contour pressing against the bearing housing, eliminating the need for separate nut installation steps and reducing manufacturing complexity.
Solution Approach 2:
The ball nut is designed with pre-formed outer contours and integrated threading that are prepared during the main manufacturing process. The bearing housing is designed with corresponding pre-formed inner contours, allowing direct pressing and fixation without requiring additional machining or assembly operations for threading and nut installation.
3Reliability
If a threaded surface is formed on the ball nut, then a nut can be used for fixation, but the material cost and manufacturing complexity increase
Solution Approach 1:
The invention combines the threading function directly into the ball nut body structure. The threaded surface is an integral part of the ball nut rather than a separate component, and the bearing fixation is achieved through the geometric configuration of the ball nut's outer surface, merging multiple functions into a single manufactured component.
Solution Approach 2:
The invention extracts the separate nut component and eliminates the need for a distinct threaded surface feature that requires additional manufacturing operations. The fixation is achieved through the overall geometric configuration of the ball nut pressing against the bearing housing, simplifying the manufacturing process.
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
This design simplifies the manufacturing process, reduces material costs, and enhances the efficiency of the mechanical actuator by eliminating the need for a threaded surface and conventional fixation means.
Implementation Method 1
performing induction hardening of the inner part of the ball nut to obtain a hardened inner part
Data Source
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Figure 5
AI summary
A mechanical actuator (200) for vehicles, comprising a ball nut (210) comprising a hardened inner part (220) defining a ball track, a malleable outer part (230) comprising a riveting area (230a) with a riveting edge (230b), and a bearing (240) riveted with the riveting edge (230b) to the riveting area (230a) of the outer part (230) of the ball nut (210).