Pedal Force Simulator Piston With Changing Cross-Section

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Solution Overview

Problem

Existing pedal force simulators for vehicles, particularly those without direct mechanical or hydraulic connections to the clutch, fail to accurately simulate the force required to operate the clutch pedal due to complex and expensive production methods of the spring elements, leading to an unfamiliar driving experience.

Innovation Solution

A pedal force simulator design featuring a piston with a changing cross-section that engages with a spring element containing rolling bodies and composed of two connected spring parts, allowing for simplified and cost-effective production, with adjustable spacer and pin-like connections for enhanced functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the spring element is designed as a one-piece component with changing cross-section, then the force simulation accuracy is improved, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improveforce simulation accuracyVSAvoidproduction complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The spring element is divided into multiple separate spring parts (first spring part, second spring part, etc.) instead of being manufactured as a single one-piece component. Each spring part can be produced independently using simpler manufacturing processes, and they are connected through connection elements to form the complete spring assembly with the desired changing cross-section profile.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the spring element is produced by milling with high precision, then the force characteristic simulation is improved, but the production cost increases

Engineering Contradiction:
Improveforce characteristic accuracyVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By segmenting the spring element into multiple simpler parts that can be manufactured using less expensive processes, the overall production cost is reduced while maintaining the force characteristic accuracy through proper design of the connection elements and arrangement of spring parts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple spring parts are combined through connection elements to create the functional equivalent of a complex one-piece spring. The combination of simpler components achieves the same force simulation effect as a precisely milled monolithic spring, but at lower manufacturing cost.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the piston has a changing cross-section engaged in the spring element, then the haptic feedback to driver is improved, but the device complexity increases

Engineering Contradiction:
Improvehaptic feedback qualityVSAvoidpiston structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The piston structure is divided into a piston body and a separate piston rod with changing cross-section. The piston rod, which provides the varying cross-sectional profile for haptic feedback, is connected to the piston body, allowing the complex geometry to be manufactured separately and assembled, thereby reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

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

The design provides a reliable simulation of the force characteristic, reducing production costs and improving the haptic feedback to the driver, while preventing jamming and allowing for adjustable distance between spring parts, thus enhancing the overall simulation accuracy and cost-effectiveness.

Implementation Method 1

rolling bodies being arranged on the spring element which are in operative connection with the piston

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP3341251B1Device for simulating a force on an actuation element of a vehicle, in particular a pedal force simulator
Publication Date: 2020.09.23 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3341251B1 patent drawingFigure 1~2
  • EP3341251B1 patent drawingFigure 2a

AI summary

The invention relates to a device for simulating a force on an actuation element of a vehicle, in particular a pedal force simulator, comprising a housing (10), a piston (20) which can be moved axially in the housing (10), said piston (20) being connected to the actuation element via a piston rod (30), and a spring element (40) which is arranged at least partly within the housing (10), in particular completely within the housing. According to the invention, the piston (20) has a changing cross-section and engages into the spring element (40) upon being actuated by the actuation element. The spring element (40) is equipped with rolling bodies (70, 80) which are operatively connected to the piston (20), and the spring element (40) consists at least of a first and a second spring part (50, 60) which are connected together.