Hydraulic Valve Isolation for Stable Telehandler Arm Positioning

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Solution Overview

Problem

Existing hydraulic control systems for telehandlers face issues with cavitation and unpredictable arm movements due to high pressures and pressure drops in hydraulic cylinders, especially when maintaining the second hydraulic cylinder in a predetermined position, leading to unwanted jerking and unpredictable arm movements.

Innovation Solution

The system replaces traditional throttles with valves that hydraulically isolate chambers when pressure exceeds a predetermined value, using elastic elements and pilot pressures to control fluid flow, preventing cavitation and maintaining stable arm positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional throttles are used to control fluid flow in hydraulic cylinders, then fluid flow can be regulated, but cavitation occurs and unpredictable arm movements result due to high pressures and pressure drops

Engineering Contradiction:
Improvearm movement stabilityVSAvoidcavitation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A check valve is introduced as an intermediary component in the hydraulic circuit between the first and second hydraulic cylinders. This check valve mediates the fluid flow direction, allowing flow from the first cylinder to the second cylinder while preventing reverse flow, thereby eliminating cavitation and stabilizing arm movements during telehandler operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional throttle mechanism is removed from the hydraulic circuit and replaced with a check valve system. This extraction of the problematic throttle component eliminates the source of cavitation and unpredictable pressure variations, while the check valve provides the necessary flow control without the harmful effects of traditional throttles

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the second hydraulic cylinder is maintained in a predetermined position using traditional pressure control, then positioning is achieved, but jerking and unpredictable arm movements occur due to pressure drops

Engineering Contradiction:
Improvepositioning stabilityVSAvoidjerking
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The check valve acts as a mediator that maintains continuous hydraulic connection between the first and second cylinders during arm movement. This prevents sudden pressure drops that cause jerking, while allowing the second cylinder to maintain its predetermined position through controlled fluid transfer from the first cylinder

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The check valve is pre-configured in the hydraulic circuit to automatically regulate fluid flow direction before pressure drops can occur. This preliminary positioning of the valve ensures that fluid flow is continuously managed, preventing the pressure variations that lead to jerking and unpredictable arm movements

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

The solution effectively prevents cavitation and stabilizes arm movements, ensuring smooth operation and precise control of the telehandler's mechanical arm and work element, reducing jerking and maintaining consistent positioning.

Implementation Method 1

a valve body (24a) comprising an elastic element (24c)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

when the pressure at the first chamber (121) exceeds a predetermined value

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

effectively prevents cavitation and stabilizes arm movements

Methodology Applied
Scientific EffectCavitation prevention: Cavitation

Data Source

PatentEP4477615B1Hydraulic control system
Publication Date: 2026.03.04 ROBERT BOSCH GMBH
  • EP4477615B1 patent drawingFigure 1
  • EP4477615B1 patent drawingFigure 2
  • EP4477615B1 patent drawingFigure 3

AI summary

The present invention relates to a hydraulic control system (100) of an actuation system to drive a working machine (98), wherein the said control system (100) comprises a first conduit and a second conduit (20, 30), wherein the said first conduit (20) comprises a first branch (21) and a second branch (22), wherein the said second conduit (30) comprises a first branch (31) and a second branch (32), wherein on the said first branch (21) of the said first conduit (20) there is a first check system (23) positioned, which is configured so as to prevent flow towards a first chamber (121) of a third cylinder (12) and to allow flow in the opposite direction, wherein on the said first branch (31) of the said second conduit (30) there is a second check system (33) positioned, which is configured so as to prevent flow towards a second chamber (122) of the said third cylinder (12) and to allow flow in the opposite direction, wherein said hydraulic control system having a first valve (24) positioned parallel to the said first check system (23) and configured in such a way as to allow a flow of fluid from the said first conduit (20) to the said first chamber (121) of the said third cylinder (12) to be cut off completely, so that the said first chamber (121) of the said third cylinder (12) is hydraulically isolated from the said first conduit and by the fact that a second valve (34) is positioned parallel to the said second check system (33) and configured in such a way as to allow a flow of fluid from the said second conduit (30) to the said second chamber (122) of the said third cylinder (12) to be cut off completely, so that the said second chamber (122) of the said third cylinder (12) is hydraulically isolated from the said second conduit (30).