Laminated Feed Screw Nut Structure for Variable Thread Lengths

Solution Overview

Problem

Conventional feed screw nut manufacturing is costly and time-consuming due to the need for cutting tools, limiting thread length and making it difficult to control the thickness of protective coatings, especially for multi-start threads.

Innovation Solution

A nut is formed by laminating plate-shaped members with inward-protruding screw threads, allowing for variable thread lengths without cutting and easy control of protective coatings, using plastic deformation and welding for assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cutting tools are used to manufacture the feed screw nut, then the threaded portion can be formed, but the thread length is limited by the length of the cutting tool and the machining time increases

Engineering Contradiction:

Improvethreaded portion formationVSAvoidmachining time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The nut is divided into multiple plate-shaped members, each with a portion of the threaded structure. By segmenting the nut into laminated plates, the manufacturing process avoids the need for long cutting tools and reduces machining time for each individual component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of forming threads by cutting away material from a solid block, the invention forms threads by laminating plate-shaped members with pre-formed threaded portions. This inverts the conventional manufacturing approach from subtractive cutting to additive lamination.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If cutting tools are used to manufacture the feed screw nut, then the threaded portion can be formed, but the manufacturing cost increases in proportion to the cutting amount

Engineering Contradiction:

Improvethreaded portion formationVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The nut is divided into multiple plate-shaped members, each with a portion of the threaded structure. By segmenting the nut into laminated plates, the manufacturing process avoids the need for long cutting tools and reduces machining time for each individual component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of forming threads by cutting away material from a solid block, the invention forms threads by laminating plate-shaped members with pre-formed threaded portions. This inverts the conventional manufacturing approach from subtractive cutting to additive lamination.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If a surface treatment for forming a protective coating on the threaded portion is performed, then wear reduction and improvement of slidability is achieved, but the thickness of the protective coating at the center portion becomes difficult to control

Engineering Contradiction:

Improvewear reduction and slidabilityVSAvoidprotective coating thickness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The nut is divided into multiple plate-shaped members, each with a portion of the threaded structure. By segmenting the nut into laminated plates, the manufacturing process avoids the need for long cutting tools and reduces machining time for each individual component.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If the feed screw nut is manufactured as a single component, then the structure is simple, but individual controls are required for each specification and the manufacturing flexibility is reduced

Engineering Contradiction:

Improvenut structureVSAvoidspecification control flexibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The nut is divided into multiple plate-shaped members, each with a portion of the threaded structure. By segmenting the nut into laminated plates, the manufacturing process avoids the need for long cutting tools and reduces machining time for each individual component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The nut structure becomes dynamic and adaptable through the lamination of plate-shaped members. Different numbers of plates can be laminated to create nuts with various thread lengths and specifications, allowing flexible adaptation to different application requirements.

Inventive Principle:

Principle #15Dynamics

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 approach reduces machining time and cost, enabling the production of nuts with various thread lengths and accurate backlash adjustment, while simplifying the manufacturing process and improving cost-effectiveness.

Implementation Method 1

the plate-shaped members are joined together

Methodology Applied

Scientific EffectWelding: Welding

Implementation Method 2

the plate-shaped members can be manufactured by forming the through hole and the screw threads through plastic deformation such as pressing or the like

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS11204056B2Nut

Publication Date: 2021.12.21 SMC CORP

AI summary

A layered nut (10) comprises a plurality of thin nuts (12) formed with through-holes (16) having almost the same diameter. On the inner peripheral surface of each thin nut (12), a plurality of screw threads (18, 38) are formed at predetermined angular spacing so as to protrude toward the inside of the through-hole (16). In this case, the thin nuts (12) are layered along the direction of the central axis (14) so that the through-holes (16) become approximately coaxial. The outer peripheral surfaces of the layered thin nuts (12) are subjected to laser welding or the like, thereby joining the thin nuts (12) and completing the layered nut (10).