Pedal Force Simulator Disk Spring Stacks with Intermediary Damping
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Solution Overview
Problem
Pedal force simulators with multiple disk spring stacks struggle to maintain a consistent spring characteristic during compression, leading to force jumps and an unnatural brake pedal sensation, which can make operating a vehicle more difficult for drivers.
Innovation Solution
Incorporating an elastically deformable spring element within an axial receiving recess, supported on the pressure piston and one of the disk spring stacks, which interacts with both disk spring stacks to dampen force jumps and maintain a consistent spring characteristic, simulating the feel of a hydraulic braking system by adjusting spring stiffness and pre-tensioning forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple disk spring stacks with different spring stiffnesses are used, then the brake pedal force sensation is simulated, but force jumps occur during compression making operation difficult
Solution Approach 1:
A cushioning element (compression element) is introduced as an intermediary component between the pressure piston and the disk spring stacks. This mediator absorbs and dampens the force jumps that occur during compression, smoothing out the spring characteristic while still allowing the disk spring stacks to provide the desired brake pedal force sensation. The cushioning element acts as a buffer that mediates between the rigid mechanical connection and the need for smooth force transmission.
Solution Approach 2:
The cushioning element is pre-installed and pre-configured in the pedal force simulator device before operation. It is designed with specific elastic properties to anticipate and compensate for the force jumps that will occur during normal brake pedal operation. By having this cushioning mechanism in place beforehand, the device prevents force jumps from reaching the brake pedal, ensuring smooth operation from the start.
2Force
If disk spring stacks are pre-tensioned between pressure piston and axial stop, then brake pedal force sensation is generated, but force jumps occur during deflection
Solution Approach 1:
The cushioning element serves as a mediator between the pre-tensioned disk spring stacks and the pressure piston. When the brake pedal is actuated and force jumps occur during disk spring stack deflection, the cushioning element absorbs these sudden force variations and transmits only smooth, continuous force to the brake pedal, maintaining the desired force sensation without the disruptive jumps.
Solution Approach 2:
The cushioning element changes the force transmission parameters by introducing elasticity and compliance into the system. It transforms the rigid, discontinuous force transmission from the disk spring stacks into a smooth, continuous force profile that maintains the brake pedal force sensation while eliminating force jumps during actuation.
3Stability of the object's composition
If spring element is added to dampen force jumps, then spring characteristic consistency is improved, but device complexity increases
Solution Approach 1:
The cushioning element is implemented as a flexible, elastomeric component with a simple geometric shape (such as a cylindrical or disc-shaped element). This flexible element provides the necessary damping function without requiring complex internal structures, multiple components, or intricate assembly procedures. Its simplicity as a single-piece flexible component minimizes the increase in device complexity while effectively dampening force jumps.
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 solution ensures a consistent and natural brake pedal force sensation by minimizing force jumps and adapting spring stiffness, making the operation of a vehicle easier by simulating the brake pedal force sensation of a conventional hydraulic braking system.
Implementation Method 1
a spring element (19), which is elastically deformable by the pressure piston (5)
Data Source
AI summary
A pedal force simulator device includes: a pressure piston actuatable by a brake pedal and axially moveably mounted in a housing; and at least two disk spring stacks connected in series, each disk spring stack having at least two disk springs, at least two of the disk spring stacks having different spring constants, and the disk spring stacks being situated in the housing between an end face of the pressure piston and an axial stop of the housing. At least one of the disk spring stacks includes an axial receiving recess, in which a spring element, which can be elastically deformed by the pressure piston, is situated, one end of the spring element being supported on the pressure piston and the other end being supported on one of the disk spring stacks.