Curved-Drive Nut Geometry for Stable High-Torque Transmission

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional hexagonal nuts have sharp edges that wear easily, leading to reduced torque transmission and increased likelihood of the wrench slipping off, making it difficult to tighten or loosen the nut, especially when rusted.

Innovation Solution

A nut design featuring a nut body with alternating driven and guiding wall portions, where the driven wall portions have curved sections and straight sections, and the guiding wall portions are straight, ensuring a stable interface with a driving tool and reducing wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional hexagonal nut with sharp edges is used, then the structure is simple and easy to manufacture, but the sharp edges wear easily leading to reduced torque transmission and wrench slippage

Engineering Contradiction:

Improvetorque transmission stabilityVSAvoidnut structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curvature by replacing the sharp edges of the conventional hexagonal nut with curved surfaces. The driven wall portions feature curved sections with defined radii of curvature, which prevent stress concentration and wear at the edges. This curvature modification maintains the hexagonal overall shape while eliminating the problematic sharp edges, thereby improving torque transmission stability and preventing wrench slippage without significantly complicating the manufacturing process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Power

If the sharp edges of the nut are worn out, then the nut becomes easier to manufacture (less material), but the contact area with the wrench decreases leading to insufficient torque transmission

Engineering Contradiction:

Improvetorque transmission capabilityVSAvoidcontact area between nut and wrench

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The curved sections on the driven wall portions increase the contact area between the nut and wrench by eliminating the sharp edges that wear down. The curvature distributes the contact pressure over a larger area, maintaining sufficient torque transmission capability even after extended use. The curved surfaces provide a more robust interface that resists wear and maintains structural integrity under repeated loading cycles.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Force

If the conventional hexagonal nut is used with rust on the threaded hole, then more torque is required to remove the nut, but the worn sharp edges make the nut fragile and difficult to unscrew

Engineering Contradiction:

Improvetorque required for removalVSAvoidnut structural strength

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

The curved sections on the driven wall portions eliminate stress concentration points that would otherwise cause the nut to become fragile during removal operations. When rust increases the torque required for removal, the curved surfaces distribute the applied force more evenly throughout the nut structure, preventing localized stress that could cause cracking or failure. This maintains structural strength even under high removal torque conditions.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The curved geometry of the driven wall portions provides a cushioning effect by distributing stress before it can concentrate at sharp edges. This pre-distribution of stress protects the nut from becoming fragile during high-torque removal operations, especially when rust is present on the threaded hole. The curved surfaces act as a buffer that absorbs and redistributes the mechanical stresses during unscrewing operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If a nut design with curved sections and alternating wall portions is used, then wear resistance and torque transmission are improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvewear resistanceVSAvoidnut manufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The curved sections are designed with specific geometric parameters (radii of curvature, central angles) that can be directly formed using conventional CNC machining or molding processes. The alternating driven and guiding wall portions follow a regular pattern that simplifies the manufacturing sequence. While the geometry is more complex than a simple hexagon, the use of standard curved surface generation techniques and the systematic arrangement of features keep the manufacturing process within reasonable complexity bounds.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS20250109765A1High torque transmission nut and driving tool therefor

Publication Date: 2025.04.03 KWANTEX RES

AI summary

A nut includes a nut body that defines a circular hole, and that has four driven wall portions and four guiding wall portions disposed about a central axis of the nut in an alternating arrangement. The driven wall portions are equiangularly spaced apart from each other. Each of the guiding wall portions is straight, and has two opposite ends that are respectively connected to two of the driven wall portions adjacent to the guiding wall portion. A ratio of a longest distance between two of the driven wall portions that are non-adjacent to each other to a longest distance between two of the driven wall portions that are adjacent to each other is greater than 1.16. Each of the driven wall portions has a curved section and two straight sections. A central angle of the curved section of each of the driven wall portions is smaller than 180 degrees.