Ride Control System with Pressure-Threshold Accumulator Damping

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Solution Overview

Problem

Ride control systems for power machines, particularly those with fixed axles and no suspension, fail to effectively dampen vibrations and shocks from terrain bumps, leading to operator discomfort and inefficient operation.

Innovation Solution

A ride control system that includes a hydraulic cylinder, an accumulator, a pressure sensor, and a controller that selectively allows communication between the accumulator and the hydraulic cylinder based on pressure thresholds, ensuring optimal damping of vibrations and shocks during travel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the accumulator is continuously connected to the hydraulic cylinder for ride control, then vibration damping is improved, but system stability and control precision deteriorate during stationary work

Engineering Contradiction:
Improvevibrations and shocksVSAvoidsystem stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The system dynamically switches between two operational modes: ride control mode (accumulator connected to hydraulic cylinder) and work mode (accumulator disconnected). This dynamic reconfiguration allows the system to adapt to different operational requirements, providing vibration damping during travel while ensuring system stability during stationary work operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the connectivity parameter between the accumulator and hydraulic cylinder based on operational conditions. During travel, the accumulator is connected to provide damping; during stationary work, the connection is severed to maintain stability. This parameter change resolves the contradiction between needing damping and maintaining stability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If manual switching is used to connect/disconnect the accumulator, then system complexity is reduced, but operational efficiency and comfort deteriorate due to operator burden

Engineering Contradiction:
Improvesystem complexityVSAvoidoperator convenience
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The system uses pressure sensors to continuously monitor hydraulic system pressure and automatically determines whether the machine is traveling or performing stationary work. Based on this feedback, the controller automatically switches between ride control and work modes, eliminating the need for manual operator intervention while maintaining optimal system performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs the switching operation autonomously based on sensed operational conditions. The controller monitors pressure signals and automatically connects or disconnects the accumulator from the hydraulic cylinder without requiring operator action, allowing the system to serve itself in managing the ride control function.

Inventive Principle:
Principle #25Self-service

3Speed

If pressure thresholds are set too high for accumulator engagement, then ride control responsiveness is improved, but system reliability deteriorates due to premature disengagement during work operations

Engineering Contradiction:
Improveresponse speedVSAvoidsystem reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system uses differentiated pressure thresholds: an initial higher threshold for engagement and a lower minimum threshold for disengagement. This parameter differentiation allows the accumulator to engage quickly when needed while preventing premature disengagement during work operations, resolving the contradiction between responsiveness and reliability.

Inventive Principle:
Principle #35Parameter changes

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 system effectively dampens vibrations and shocks, improving operator comfort and machine stability by selectively engaging and disengaging the accumulator and hydraulic cylinder based on pressure conditions, enhancing the overall ride control experience.

Implementation Method 1

Ride control can improve the comfort of an operator, especially in a power machine having fixed axles with no suspension. Typically, ride control is accomplished by exposing the base end of the lift cylinder or cylinders to an accumulator. Pressurized fluid moves between the base end of the cylinder and the accumulator and moves between a reservoir and the rod end to allow the lift arm assembly to oscillate up and down.

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

a pressure sensor capable of communicating a signal indicative of a hydraulic pressure at the first end of the hydraulic cylinder

Methodology Applied
Scientific EffectPressure sensing:

Data Source

PatentEP3289143B1Ride control system for power machine
Publication Date: 2023.06.14 DOOSAN BOBCAT NORTH AMERICA INC
  • EP3289143B1 patent drawingFigure 1
  • EP3289143B1 patent drawingFigure 2
  • EP3289143B1 patent drawingFigure 3

AI summary

A ride control system (300) for a power machine (100) having a lift arm (116) movably coupled to a frame (102). A hydraulic cylinder (120) configured to selectively control movement of the lift arm relative to the frame. An accumulator (340) is in selective communication with a first end of the hydraulic cylinder. A pressure sensor (325) communicates a signal indicative of a hydraulic pressure at a first end of the hydraulic cylinder. A ride control circuit (330) allows selective communication between the accumulator and the first end of the hydraulic cylinder. A controller (320) receives the signal from the pressure sensor, and prevents communication between the accumulator and the first end of the hydraulic cylinder until the signal from the pressure sensor indicates a pressure below an initial pressure threshold value.