Ball Screw Nut Circulator Groove for Stable Radial Positioning

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Solution Overview

Problem

Existing ball screw devices face issues with radial displacement of internal circulators due to methods like bolt fastening, perforations, or adhesive dispensing, leading to unsmooth operation and difficulty in assembling small nut sizes.

Innovation Solution

The use of an assembly groove with a narrow neck near the inner ring wall and a circulator with a corresponding shape, allowing the circulator to be fixed without additional locking components, preventing radial displacement and facilitating assembly by insertion along the axial direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bolts, screws, or adhesive dispensing are used to fasten the circulator, then the circulator can be secured in the nut, but radial movements of the circulator still occur causing unsmooth operation

Engineering Contradiction:
Improvecirculator fixation stabilityVSAvoidoperation smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A retainer is introduced as an intermediary component between the circulator and the nut body. The retainer has a first end that contacts the circulator and a second end that is constrained by the narrow neck of the assembly groove, preventing radial movement of the circulator without requiring direct fastening to the nut body.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the mechanical fastening system (bolts, screws, or adhesive) with a geometric constraint system. The asymmetric assembly groove with its narrow neck creates a mechanical constraint that prevents radial displacement of the circulator through shape complementarity rather than through fastening forces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Volume of moving object

If smaller screws, bolts, or perforations are used to accommodate small nut sizes, then the circulator can be arranged in small nuts, but the assembling becomes much more difficult

Engineering Contradiction:
Improvenut sizeVSAvoidassembling difficulty
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The retainer serves as a mediator that simplifies assembly in small nuts. Instead of dealing with difficult-to-install small fasteners, the circulator is simply placed into the assembly groove where the retainer automatically constrains it radially, making the assembly process straightforward even in compact spaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The assembly groove with its narrow neck provides self-constraining functionality. When the circulator is placed in the groove, the narrow neck automatically prevents radial movement without requiring additional fastening operations, making the assembly process self-completing and eliminating complex fastening steps.

Inventive Principle:
Principle #25Self-service

3Reliability

If additional locking components such as screws or bolts are used to prevent radial displacement, then the circulator can be secured, but the device complexity increases

Engineering Contradiction:
Improvecirculator position stabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retainer and the assembly groove are merged into a single integrated component. The retainer is formed as part of the nut body structure, with the narrow neck of the assembly groove serving as the constraining feature. This integration eliminates the need for separate locking components while maintaining circulator position stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The assembly groove serves multiple functions: it provides a pathway for circulator installation and simultaneously acts as a constraint mechanism through its narrow neck. This multi-functionality eliminates the need for separate locking features, reducing overall device complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively prevents radial movement and assembly challenges, ensuring smooth operation and easier assembly of the circulator within small nut sizes without the need for screws or bolts, enhancing the stability and ease of assembly of the ball screw device.

Implementation Method 1

the assembly groove with the narrow neck near the inner ring wall and the circulator with the shape of the cross section corresponding to that of the assembly groove, when the circulator is arranged in the assembly groove under the limit of the narrow neck, radial displacement of the circulator towards the inner ring wall of the nut body can be avoided

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Implementation Method 2

the circulator may be fixedly arranged in the assembly groove of the nut body through glue

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3957878B1Nut and ball screw device
Publication Date: 2023.04.19 LEE SZU YING
  • EP3957878B1 patent drawingFigure 1
  • EP3957878B1 patent drawingFigure 2
  • EP3957878B1 patent drawingFigure 3~4

AI summary

A ball screw device (100) includes a screw (10), a nut (20) and a plurality of balls (30). A nut body (21) includes an inner ring wall (213), a ball groove (214) and an assembly groove (215, 215a, 215b). The assembly groove (215, 215a, 215b) is axially arranged in the inner ring wall (213) and runs through two axial ends (211, 212) of the nut body (21). Viewed from an axial end (211, 212) of the nut body (21), a shape of the assembly groove (215, 215a, 215b) includes a narrow neck (2151, 2151a, 2151b) and a wide neck (2152, 2152a, 2152b) along a radial cross section of the nut body (21). A circulator (22, 22a, 22b) is arranged in the assembly groove (215, 215a, 215b), where a shape of the circulator (22, 22a, 22b) corresponds to the shape of the assembly groove (215, 215a, 215b), the circulator (22, 22a, 22b) is provided with a guiding groove (221) facing the inner ring wall (213), and the guiding groove (221) and the ball groove (214) form a ball circulating channel. The plurality of balls (30) rolls in the ball circulating passage formed by a track groove (11) and the ball circulating channel.