Hydrostatic Drive Steering Without Control Valves

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing self-propelled work machines with hydrostatic drive systems require complex control valves for steering, which complicates the design and increases maintenance needs.

Innovation Solution

A single-axle work machine with a hydrostatic drive device featuring dependent or independent control of hydraulic motors for each drive wheel, utilizing adjustable hydraulic pumps connected to electric motors for precise fluid delivery, eliminating the need for control valves through a compact and maintenance-friendly design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If control valves are used for steering in hydrostatic drive systems, then steering control is achieved, but device complexity and maintenance needs increase

Engineering Contradiction:
Improvesteering controlVSAvoidcontrol valve complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the control valves from the hydrostatic drive system. Instead of using control valves to regulate hydraulic fluid flow for steering, the invention uses a mechanical linkage system that directly connects the steering wheel to the drive wheels, bypassing the hydraulic control system entirely. This removes the complex control valve component while preserving steering functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the hydraulic control mechanism (control valves) with a direct mechanical linkage system. The steering wheel is mechanically connected to the drive wheels through linkages that transmit steering input directly, substituting the hydraulic fluid control approach with a straightforward mechanical transmission approach.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If control valves are used for steering, then steering function is achieved, but maintenance complexity increases

Engineering Contradiction:
Improvesteering functionVSAvoidmaintenance complexity
Core Design Contradiction:
Ease of operationVSEase of repair

Solution Approach 1:

The patent removes control valves from the system, eliminating a major maintenance burden. Hydraulic control valves require periodic maintenance including seal replacement, fluid contamination checks, and potential recalibration. By extracting these components entirely and using a mechanical linkage system, the invention dramatically reduces maintenance requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical linkage system uses simple, inexpensive components that are easier and cheaper to replace than hydraulic control valves. If wear occurs in the mechanical linkages, the components can be quickly replaced without requiring specialized hydraulic knowledge or equipment, making maintenance more accessible and less costly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If hydraulic pumps are made adjustable for precise fluid delivery, then steering precision improves, but device complexity increases

Engineering Contradiction:
Improvesteering precisionVSAvoidpump control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the adjustable hydraulic pump control system with a direct mechanical linkage. Steering precision is achieved not through precise hydraulic fluid delivery control, but through direct mechanical transmission of the steering wheel's rotational movement to the drive wheels. The mechanical linkage naturally provides precise control through its geometric relationship between components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables straightforward, controllable steering without control valves, enhancing the machine's maneuverability and reducing maintenance complexity while maintaining a compact and efficient design.

Implementation Method 1

a driven hydrostatic drive device for steerable locomotion by means of hydraulic motors of a drive unit

Methodology Applied
Scientific EffectHydraulic drive: Hydraulic Press

Implementation Method 2

The hydraulic pump of a drive unit by a controllable motor, preferably an electric motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2607209B1Self-propelled work machine with at least one axle for operating and/or transporting attached work devices or attached vehicles
Publication Date: 2019.01.30 RAPID TECHNIC
  • EP2607209B1 patent drawingFigure 1
  • EP2607209B1 patent drawingFigure 2~5
  • EP2607209B1 patent drawingFigure 6~8

AI summary

The machine has hydrostatic drive unit (3) for steerable movement of the drive wheels of drive axle, which is connected to hydraulic motor. The drive axle is electromechanically connected to adjustable hydraulic pump (25,26) of drive unit (30,31).