Ball Screw Spline Assembly Layout to Avoid Pulley-Bolt Interference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current ball screw spline installations in SCARA robots require disassembly for maintenance, leading to inconvenience and increased size due to pulley interference with bolts, hindering automatic assembly and production.

Innovation Solution

A ball screw spline assembly with integrated nuts and a connecting plate allows for integral installation to a housing, eliminating the need to remove nuts from the shaft and preventing pulley interference with bolts, enabling compact and automatic assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the ball screw spline is disassembled for installation and maintenance, then the spline nut can be removed from the shaft, but the installation process becomes inconvenient and time-consuming

Engineering Contradiction:
Improveinstallation convenienceVSAvoidinstallation time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent combines the first nut and second nut into a single integrated ball screw spline assembly that mounts to the housing as one unit. The first nut is integrated with the second nut, eliminating the need to separately remove and reinstall individual nuts during maintenance, thereby reducing installation time and improving operational convenience.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If the pulley is separated from the bolts by a distance, then interference between pulley and bolts is avoided, but the assembly size increases

Engineering Contradiction:
Improvepulley-bolt interferenceVSAvoidassembly size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent repositions the mounting surfaces of both nuts within the three-dimensional space defined by the housing and connecting plate. By locating the first mounting surface and second mounting surface within the available space, the design allows the pulley to be closer to the nuts without interfering with bolts, thus reducing assembly size while avoiding interference through spatial optimization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3720662B1Ball screw spline assembly and related method
Publication Date: 2025.06.25 ABB (SCHWEIZ) AG
  • EP3720662B1 patent drawingFigure 1~2
  • EP3720662B1 patent drawingFigure 3~4
  • EP3720662B1 patent drawingFigure 5~6

AI summary

A ball screw spline assembly comprises: a ball screw spline (500) including a first nut (520) including a first mounting surface (522) adapted to receive a first fastening element (230) for installing the first nut (520) to a housing; a second nut (530) including a second mounting surface (532) adapted to receive a second fastening element (240) for installing the second nut (530) to the housing; and a shaft (510) passing through the first nut (520) and the second nut (530); the housing including a first portion (600) and a second portion (650), wherein the first portion (600) extends in a direction substantially parallel to the shaft (510), and the second portion (650) extends in a direction substantially perpendicular to the shaft (510); a connecting plate (540) coupling the second nut (530) to the first portion (600), wherein the first nut (520) is installed to the second portion (650); wherein the first mounting surface (522) and the second mounting surface (532) are located within a space defined by the first portion (600), the second portion (650) and the connecting plate (540), such that the ball screw spline (500) is integrally installable to the housing. And a method for installing the ball screw spline is also disclosed. The ball screw spline (500) is integrally installable to the housing, and thus there is no need to remove the spline nut from the shaft (510) when installing and maintaining the ball screw spline (500). With the bolts adapted to be received within the housing without protruding from the housing, the robot arm comprising the ball screw spline assembly can be compact since the pulley no longer interferes with the bolts mounted on the spline nut.