Chainsaw Oil Pump Throttling for Jammed Lubrication Passages

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Solution Overview

Problem

The oil passage in chainsaws can become jammed, preventing the chain from being fully lubricated or cooled, which affects the cutting operation.

Innovation Solution

A controller is integrated into the chainsaw to detect a jammed liquid pump state and implement a throttling mode to reduce the liquid supply, gradually relieving the jam by reducing the motor's working frequency or power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the liquid pump operates at normal speed to provide sufficient lubrication and cooling, then the chain is fully lubricated or cooled, but the oil passage may become jammed

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidjammed state
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the liquid pump's operating state between normal mode and throttling mode based on real-time detection of jammed conditions. The controller monitors the liquid pump's operational status and automatically switches between different operating frequencies to maintain reliable lubrication while preventing passage blockage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the operating parameter (frequency) of the liquid pump motor. When a jammed state is detected, the controller reduces the motor's working frequency or power, thereby reducing the liquid flow rate to gradually relieve the blockage while preventing complete shutdown.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the liquid pump operates continuously at full power, then sufficient liquid is supplied for lubrication, but the jammed state cannot be relieved

Engineering Contradiction:
Improveliquid supply amountVSAvoidjammed state relief
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system implements periodic operation by alternating between normal operation and throttling mode. When jamming is detected, the controller reduces the liquid pump's operating frequency for a period, then restores normal operation when the blockage is relieved, creating a periodic cycle that prevents sustained blockage.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The controller continuously monitors the liquid pump's operational status and provides feedback control. When the monitoring module detects abnormal current or voltage indicating a jammed state, the controller automatically adjusts the motor power downward, and when normal operation is restored, the controller returns to full power operation.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If the motor power is reduced to relieve the jammed state, then the liquid flow is reduced to clear the blockage, but the lubrication effectiveness decreases

Engineering Contradiction:
Improvejammed stateVSAvoidlubrication effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system dynamically switches between two operating states: normal mode for adequate lubrication and throttling mode for jam relief. The controller rapidly transitions between these states based on real-time detection, ensuring that lubrication effectiveness is maintained during normal operation while enabling quick response to blockage conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The monitoring module continuously detects early signs of jamming (current or voltage changes) before complete blockage occurs. The controller takes preliminary action by reducing power at the first sign of trouble, preventing full jamming while minimizing impact on lubrication effectiveness.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4344809B1chainsaw
Publication Date: 2025.01.29 NANJING CHERVON IND
  • EP4344809B1 patent drawingFigure 1
  • EP4344809B1 patent drawingFigure 2~3
  • EP4344809B1 patent drawingFigure 4

AI summary

A chainsaw (10) includes a chain (100), a liquid pump assembly (400), a motor, and a controller (620). The chain (100) is used for implementing a cutting operation. The liquid pump assembly (400) includes a liquid pump (410) and a motor. The liquid pump (410) is used for releasing a liquid for lubricating or cooling the chain (100). The motor is used for at least driving the liquid pump (410) to operate. The controller (620) is electrically connected to at least the motor. The controller (620) is configured to, when the liquid pump (410) is in the jammed state, control the liquid pump assembly (400) to enter a throttling mode in which a supplied amount of the liquid is reduced, and when the liquid pump (410) exits the jammed state, control the liquid pump assembly (400) to exit the throttling mode. Technical solutions provided by the present application can determine and release the jammed state of the chainsaw (10).