Electric Tool Two-Plunger Hydraulic Pump for Fast Pressure Rise

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Solution Overview

Problem

Existing electric tools consume excessive battery power during repeated operations like pressing and crimping due to high motor loads, and require inefficient hydraulic pressure transitions from low to high pressure.

Innovation Solution

The electric tool incorporates a hydraulic pump with a swash plate cam and plungers, featuring different plunger configurations for varying liquid feeding amounts and pressures, along with a relief valve to reduce motor load and expedite pressure transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the electric motor operates at high power to quickly increase hydraulic pressure from low to high, then the operation time is shortened, but the battery consumption increases and motor load increases

Engineering Contradiction:
Improveoperation timeVSAvoidbattery consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The hydraulic pump is divided into two independent plunger systems (first plunger and second plunger) that operate in sequence. The first plunger handles low-pressure liquid feeding while the second plunger handles high-pressure liquid feeding, allowing the system to transition through pressure stages without requiring the entire system to operate at maximum power continuously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different plunger configurations based on pressure requirements. A check valve on the first plunger opens at a first pressure threshold, automatically transferring liquid feeding responsibilities from the first plunger to the second plunger as pressure increases, optimizing power usage at each stage.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the electric motor operates at high power to perform repeated pressing and crimping operations, then the productivity is improved, but the battery consumption increases

Engineering Contradiction:
Improverepeated operation capabilityVSAvoidbattery consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The hydraulic pump is divided into two independent plunger systems (first plunger and second plunger) that operate in sequence. The first plunger handles low-pressure liquid feeding while the second plunger handles high-pressure liquid feeding, allowing the system to transition through pressure stages without requiring the entire system to operate at maximum power continuously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hydraulic system performs periodic pressure cycles by alternating between the first plunger (low pressure) and second plunger (high pressure) phases. The check valve enables automatic periodic switching between pressure stages, allowing repeated operations with optimized energy consumption at each cycle.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If the hydraulic pump uses a single plunger configuration for both low and high pressure, then the device complexity is reduced, but the operation time increases due to slow pressure transition

Engineering Contradiction:
Improveplunger configurationVSAvoidpressure transition time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The hydraulic pump is divided into two independent plunger systems (first plunger and second plunger) that operate in sequence. The first plunger handles low-pressure liquid feeding while the second plunger handles high-pressure liquid feeding, allowing the system to transition through pressure stages without requiring the entire system to operate at maximum power continuously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes operational parameters by switching between different plunger configurations based on pressure requirements. The first plunger operates with parameters optimized for low-pressure feeding while the second plunger operates with parameters optimized for high-pressure feeding, enabling rapid pressure transition without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

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

This configuration reduces battery consumption and shortens operation time by efficiently managing hydraulic pressure transitions while maintaining a reduced motor load.

Implementation Method 1

The hydraulic pump has a swash plate cam 7a rotated while being coupled to a drive shaft 8a of the electric motor 8, and a plurality of plungers 11, 12 disposed around an axis P1 passing through the drive shaft 8a in the cylinder part 4 and reciprocating while being in contact with the swash plate cam 7a

Methodology Applied
Scientific EffectSwash plate cam mechanism: Swashplate

Implementation Method 2

A first plunger 11 of the plungers is provided with a check valve 15 that opens at a first pressure on a secondary side

Methodology Applied
Scientific EffectPressure-dependent valve opening: Valve

Implementation Method 3

A relief valve 26 that opens at a second pressure higher than the first pressure is disposed in the cylinder part 4

Methodology Applied
Scientific EffectPressure relief: Valve

Implementation Method 4

a hydraulic pump 7 for feeding hydraulic oil 3a inside the oil tank 3 to the cylinder part 4

Methodology Applied
Scientific EffectHydraulic pressure generation: Hydraulic Press

Data Source

PatentEP4257297B1Electric tool
Publication Date: 2025.09.17 MAXELL IZUMI CO LTD
  • EP4257297B1 patent drawingFigure 1
  • EP4257297B1 patent drawingFigure 2A~2C
  • EP4257297B1 patent drawingFigure 3A~3B

AI summary

An electric tool (1) is configured that oil pressure can be rapidly increased while suppressing the load on a motor. The electric tool (1) comprises a main body (2) in which a cylinder part (4) and a hydraulic pump (7) for feeding hydraulic oil (3a) to the cylinder part (4) and an electric motor (8) are disposed, and a tool head (9) operated by a pressing force of a piston (4a) in the cylinder part (4). The hydraulic pump (7) has a swash plate cam (7a) and a first plunger (11) and a second plunger (12) and a check valve (15) and a relief valve (26), and until the pressure reaches the first pressure, a first liquid feeding amount of the first plunger (11) is increased than a second liquid feeding amount of the second plunger (12).