Working Vehicle Quick Hitch Pressure Oil Return Control

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Solution Overview

Problem

Conventional working vehicles require dedicated service pipes and solenoid valves for returning pressure oil, leading to high component costs and complex piping layouts.

Innovation Solution

A working vehicle configuration that eliminates dedicated service pipes and solenoid valves by using a control valve unit with a service actuator control valve, solenoid valves, and a controller to automatically return pressure oil to a hydraulic oil tank when the quick hitch lock is released, simplifying the piping layout and reducing component costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated service pipes and dedicated solenoid valves are used to return pressure oil, then the pressure oil return function is reliable, but the component cost increases and the piping layout becomes complicated

Engineering Contradiction:
Improvepressure oil return functionVSAvoidpiping layout and component quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the pressure oil return function into the existing service actuator control valve by utilizing its solenoid valve and spool mechanisms. The control valve's secondary side oil passage is used to return pressure oil from the quick hitch, eliminating the need for separate dedicated service pipes and solenoid valves. This integration maintains functional reliability while significantly simplifying the piping layout and reducing component quantity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The service actuator control valve is given multiple functions: it controls both the service actuator and the pressure oil return from the quick hitch. The solenoid valve on the control valve serves dual purposes by controlling both service actuator operation and pressure oil return flow. This multi-functionality reduces the overall number of components needed in the hydraulic system.

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

2Device complexity

If the first drive unit is stopped during pressure oil return, then component costs are reduced and piping is simplified, but control precision is required to prevent incorrect operation

Engineering Contradiction:
Improvepiping layout and component quantityVSAvoidoperation safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The controller is programmed to stop the first drive unit before activating the solenoid valve for pressure oil return. This preliminary action ensures that no new pressure oil is supplied to the quick hitch during the return process, preventing potential incorrect operation. The controller also manages the timing sequence to ensure the drive unit restarts only after the pressure oil return is complete, maintaining operational safety throughout the process.

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 configuration achieves a simpler and safer working vehicle with automated pressure oil return, reducing component costs and simplifying piping while ensuring reliable and safe operation.

Implementation Method 1

a plurality of solenoid valves of the service actuator control valve

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

the pressure oil in the plurality of pipelines is returned to the hydraulic oil tank

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4428310B1Working vehicle
Publication Date: 2025.09.10 TAKEUCHI MFG CO LTD
  • EP4428310B1 patent drawingFigure 1
  • EP4428310B1 patent drawingFigure 2
  • EP4428310B1 patent drawingFigure 3

AI summary

A working vehicle (1) includes a control valve unit (10) with a service actuator control valve (13a), a first drive unit (15), a travel unit (6), a lower body (2), an upper body (3), a cab (4), a plurality of work units (7, 14) and a plurality of hydraulic traveling motors (17a, 17b), an operation unit (5), a quick hitch (55), an attachment (51d), a trigger-switch (30), a plurality of solenoid valves (71a, 71b) and a plurality of pipelines (73, 74), and a controller (9). The controller (9) performs control that, in a case where the controller (9) receives the trigger signal from the trigger-switch (30) to release the lock of the quick hitch (55), the pressure oil in the plurality of pipelines (73, 74) is returned to the hydraulic oil tank (54) by energizing the plurality of solenoid valves (71a, 71b) with the first drive unit (15) stopped.