Parallel Hydraulic Pump Layout for High-Flow Work Machines

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Solution Overview

Problem

Existing hydraulic systems in work machines like excavators waste energy due to the need for large displacement pumps to meet high flowrate demands, resulting in high costs, bulkiness, and poor efficiency at low flowrates.

Innovation Solution

A hydraulic arrangement with a common pressure rails (CPR) configuration using multiple parallel hydraulic lines and accumulators to manage different pressure levels, allowing simultaneous connection of multiple pumps to actuators, optimizing pump size and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single hydraulic pump is sized to meet high flowrate demands, then high flowrate is achieved, but pump size, weight, cost, and bulkiness increase while efficiency at low flowrates deteriorates

Engineering Contradiction:
ImproveflowrateVSAvoidpump weight
Core Design Contradiction:
ProductivityVSWeight of stationary object

Solution Approach 1:

The patent divides the single large pump into multiple smaller pumps operating in parallel. Each pump is sized for partial flowrate requirements, and they collectively deliver the total required flowrate. This segmentation allows each pump to operate at optimal efficiency points while reducing individual pump weight and cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple smaller pumps into a unified hydraulic system with common pressure rails. The pumps work together to provide the necessary flowrate and pressure, merging their outputs to achieve the system's total hydraulic requirements while maintaining efficiency advantages of smaller individual units.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If a single hydraulic pump is sized to meet high flowrate demands, then high flowrate is achieved, but pump size, weight, cost, and bulkiness increase while efficiency at low flowrates deteriorates

Engineering Contradiction:
ImproveflowrateVSAvoidpump force
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent segments the hydraulic power source into multiple smaller pumps, each contributing a portion of the total flowrate. This allows the system to meet high flowrate demands through combined output while each individual pump remains compact and lightweight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple pump outputs are merged through common pressure rails to deliver the cumulative flowrate and pressure required by hydraulic actuators. The combined system achieves the necessary force and flowrate without requiring any single oversized pump.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If a single hydraulic pump is sized to meet high flowrate demands, then high flowrate is achieved, but pump size, weight, cost, and bulkiness increase

Engineering Contradiction:
ImproveflowrateVSAvoidhydraulic system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The hydraulic system is segmented into multiple independent pump units that can be individually controlled and maintained. This modular approach, while adding numerical complexity, simplifies overall system management through standardized components and parallel operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple pump systems into a unified hydraulic architecture with common pressure rails and control mechanisms. This integration reduces the net increase in complexity by providing a standardized framework for managing multiple pump units.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If a single hydraulic pump is sized to meet high flowrate demands, then high flowrate is achieved, but efficiency at low flowrates deteriorates

Engineering Contradiction:
ImproveflowrateVSAvoidpump efficiency
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

By dividing the total flowrate requirement among multiple smaller pumps, each pump can operate within its optimal efficiency range. This prevents the inefficiency that occurs when a single large pump operates at low flowrates, as each unit can maintain efficient operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The combined output of multiple efficiently operating pumps delivers the total required flowrate while maintaining high overall system efficiency. The merging of multiple efficient small-scale operations achieves better energy utilization than a single inefficient large-scale operation.

Inventive Principle:
Principle #5Merging (Combining)

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 enables high flowrates without oversizing pumps, reducing weight, cost, and improving efficiency by using smaller, lighter pumps, while optimizing hydraulic system design.

Implementation Method 1

at least two hydraulic accumulators (26, 27), each fluidly connected to a corresponding one among the at least two hydraulic lines (21, 22) and each configured to set the pressure at the corresponding hydraulic line (21, 22)

Methodology Applied
Scientific EffectHydraulic Accumulator: Hydraulic Accumulator

Data Source

PatentEP4575104A1Improved work machine
Publication Date: 2025.06.25 CNH IND ITALIA SPA
  • EP4575104A1 patent drawingFigure 1
  • EP4575104A1 patent drawingFigure 2
  • EP4575104A1 patent drawingFigure 3

AI summary

Work machine (1) comprising a body, a hydraulically actuated articulated arm carried by said body; a plurality of hydraulic actuators (4) configured to actuate said body and/or said hydraulically actuated articulated arm; and a hydraulic arrangement (12), which is fluidly connected to said hydraulic actuators (4) in order to actuate said hydraulic actuators (4). The hydraulic arrangement (12) comprises a first hydraulic pump (30) and a second hydraulic pump (31) arranged in parallel to each other; and a hydraulic circuit (18), which is configured to put each hydraulic pumps (30, 31) in fluid communication with the hydraulic actuators (4); and a hydraulic line (45) arranged in parallel to the hydraulic circuit (18), which is adapted to fluidly connect the outlet of both said first hydraulic pump (30) and said second hydraulic pump (31) with at least one among said hydraulic actuators (4) at the same time.