Hydraulic Traction Motor Valve With Independent Pressure Compensator Control

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Solution Overview

Problem

Existing control valves for hydraulic traction motors require fixed coordination between the inlet and outlet sides, limiting adaptability to driving situations and necessitating complex coordination mechanisms.

Innovation Solution

Incorporation of a proportional valve device that controls the pressure compensators based on traction motor speed and inlet pressure, allowing independent control of the inflow and outflow paths, and integration of electrically controlled pressure reducing valves to adjust braking as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed assignment of inlet side and outlet side of the traction motor is provided with coordination between control valve inlet and outlet sides, then the control valve can maintain stable hydraulic coupling, but the adaptability to driving situations is limited and the device complexity increases due to coordination requirements

Engineering Contradiction:
Improvehydraulic coupling stabilityVSAvoidadaptability to driving situations
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by making the control valve adaptable to different driving situations through variable control characteristics. The control valve can dynamically adjust its behavior based on operating conditions, allowing the inlet and outlet sides to be independently controlled rather than fixed. This enables the system to adapt to varying driving requirements while maintaining reliable hydraulic coupling when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the control of inlet and outlet sides of the traction motor into independent control paths. By providing separate control mechanisms for each side, the system eliminates the need for coordination between inlet and outlet sides, allowing independent optimization of each path according to specific driving conditions while maintaining system reliability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If coordination between inlet side and outlet side control on the control valve is provided, then hydraulic coupling is maintained, but the device complexity and control mechanisms required increase

Engineering Contradiction:
Improvehydraulic couplingVSAvoidcoordination mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control valve is designed with segmented control paths for the inlet and outlet sides of the traction motor. Each side has its own independent control mechanism, eliminating the need for complex coordination systems while maintaining reliable hydraulic coupling through proper design of the segmented control architecture.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If pressure compensator control is made adaptable to driving situations through proportional valve device, then braking control flexibility is improved and adaptability increases, but the device complexity increases due to additional control components

Engineering Contradiction:
Improvebraking control flexibilityVSAvoidcontrol components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the proportional valve device functionality directly into the control valve structure. By integrating the proportional control mechanism within the existing control valve, the system achieves adaptable braking control without adding separate external control components, thus improving flexibility while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control valve is designed with multi-functionality, serving both as a directional control valve and as a proportional control valve for pressure compensator control. This universal design allows the same component to provide both basic directional control and advanced proportional braking control, reducing the need for additional specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 flexible braking of the traction motor by adapting pressure compensators to driving conditions, simplifying control and reducing the need for complex coordination, while integrating brake functions into the control valve.

Implementation Method 1

a first pressure compensator (DW1) which controls the pressure medium flow in the first inflow path (21a) from a pump (2) to the drive motor (6)

Methodology Applied
Scientific EffectPressure compensation:

Implementation Method 2

a second pressure compensator (DW2) which controls the pressure medium flow in the first outflow path (22a) from the drive motor (6) to a tank (4)

Methodology Applied
Scientific EffectPressure compensation:

Implementation Method 3

a proportional valve device (30) is provided by means of which, in the first control position (20b) of the control slide (11), the actuation of the second pressure compensator (DW2) in the direction of a blocking position (SST) can be controlled as a function of the speed of the traction motor (6) and/or as a function of the inlet pressure of the traction motor (6)

Methodology Applied
Scientific EffectProportional control:

Data Source

PatentEP4624761A1Control valve for load-independent control of a hydraulic traction motor
Publication Date: 2025.10.01 LHY POWERTRAIN GMBH & CO KG
  • EP4624761A1 patent drawingFigure 1
  • EP4624761A1 patent drawingFigure 2
  • EP4624761A1 patent drawingFigure 3

AI summary

The invention relates to a control valve (10) for load-independent control of a hydraulic traction motor (6) with a control slide (11) for controlling the direction of movement and the speed of movement of the traction motor (6), wherein the control valve (10) is connected to a pump connection (P), to a container connection (T1; T2), to at least one load pressure signaling line connection (LS1; LS2), to a first traction motor connection (A) and to a second traction motor connection (B), wherein the control valve (10) comprises a first pressure compensator (DW1) and a second pressure compensator (DW2).A proportional valve device (30) is provided, by means of which, in a first control position (20b) of the control slide (11), the actuation of the second pressure compensator (DW2) in the direction of a blocking position (SST) can be controlled as a function of the speed of the traction motor (6) and/or as a function of the inlet pressure of the traction motor (6) present at the first traction motor connection (A), and by means of which, in a second control position (20c) of the control slide (11), the actuation of the first pressure compensator (DW1) in the direction of a blocking position (SST) can be controlled as a function of the speed of the traction motor (6) and/or as a function of the inlet pressure of the traction motor (6) present at the second traction motor connection (B).