Multi-Pitch Helical Spring for Ball Screw Brake Assembly

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Solution Overview

Problem

The assembly of miniaturized ball screw assemblies with many components, including rolling elements and coil springs in a curved thread, is complex and inefficient, leading to challenges in operating function and process reliability, particularly in enabling simple automated assembly and increasing cycle times.

Innovation Solution

A helical spring element with differently designed sections, featuring increased transverse rigidity at the contact section and varying pitches, along with a double-coil shape and inclined contact surface, is used to facilitate easier adaptation to the thread and improve assembly efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a traditional single-pitch helical spring element is used in the ball screw transmission, then the spring can adapt elastically to the helically wound thread, but the assembly process becomes complex and inefficient with multi-piece components

Engineering Contradiction:
Improveassembly processVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The helical spring element is divided into different sections with different pitches - a first section with pitch p1 for adapting to the thread, and a second section with pitch p2 for providing support. This segmentation allows the spring to serve multiple functions while remaining a single integrated component, simplifying assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-pitch helical spring element performs multiple functions: it adapts elastically to the helically wound thread in the first section, provides support in the second section, and maintains rolling elements in the thread. This multi-functionality eliminates the need for separate adjustment devices and reduces the number of components.

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

2Reliability

If rolling elements are arranged with limited mobility between stops in the thread, then the transmission can maintain position under load, but the assembly process becomes more complex

Engineering Contradiction:
Improveposition holding capabilityVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The helical spring element automatically maintains the rolling elements in the thread through its elastic adaptation to the helically wound thread. The spring's geometry and elasticity cause it to self-adjust and hold the rolling elements in position without requiring additional adjustment devices or complex assembly procedures.

Inventive Principle:
Principle #25Self-service

3Productivity

If a helical spring element with varying pitches is used, then assembly efficiency increases and automated assembly becomes possible, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveassembly cycle timeVSAvoidspring geometry precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The helical spring element features different pitch parameters in different sections - pitch p1 in the first section for thread adaptation and pitch p2 in the second section for support. This parameter variation is designed into the spring geometry to enable automated assembly while maintaining the necessary functional precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The helical spring element is pre-formed with the multi-pitch geometry and elastic properties required for the application. This preliminary preparation of the spring with its specific geometric parameters enables automated assembly processes and reduces assembly cycle time.

Inventive Principle:
Principle #10Preliminary action

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 enhances the assembly process by allowing for centric force introduction and reduced friction, achieving efficient operation with high efficiency (85-95%) and eliminating the need for separate adjustment devices, while maintaining robustness and cost-effectiveness.

Implementation Method 1

When the transmission is actuated under load, the rolling elements roll off in the thread. As a result, a relatively high degree of efficiency of 85% to 95% is achieved

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

a coil spring element is provided, which maintains a rolling path for rolling of the rolling elements 4 in the thread between the rolling elements 4 and a first stop

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3033547B1Combined vehicle brake with a ball screw drive
Publication Date: 2019.03.27 CONTINENTAL TEVES AG & CO OHG
  • EP3033547B1 patent drawingFigure 1
  • EP3033547B1 patent drawingFigure 2~3
  • EP3033547B1 patent drawingFigure 4~5

AI summary

The invention relates to a combined vehicle brake which has a hydraulically actuable service brake and an electromechanically actuable parking brake device. The present invention is based on the problem of improving the known ball screw drives for use in vehicle brakes, of making simple automated assembly possible, and in addition of opening up the possibility to increase cycle times. In order to solve said problem, it is proposed that a spring element (10) of double helical type which is configured differently in sections is provided, by means being provided in a middle section (22), that is to say in the drive thread turn, which means substantially do not impede the elastically pliable adaptation of the spring element (10) to the helically wound drive thread turn, and wherein a bearing section (24) is additionally provided at at least one end of the spring element (10), which bearing section (24) has an increased transverse rigidity or has it impressed onto it in comparison with the middle section (22).