Impact Tool Feedback Control for Stable Torque During Discharge

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Solution Overview

Problem

Impact tools using direct current power supplies experience a decrease in output torque as the power source is consumed, affecting user experience.

Innovation Solution

An impact tool with a controller that adjusts the electric motor's running parameters, such as duty cycle and conduction angle, to maintain a consistent torque output by matching the electric motor's voltage to the battery set's current voltage, ensuring the difference in torque remains within a preset parameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a direct current power supply is used to power the impact tool, then the tool can operate portably and deliver high initial torque, but the output torque decreases as the battery power is consumed

Engineering Contradiction:
Improveoutput torqueVSAvoidbattery power consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The controller continuously monitors the voltage of the battery set and adjusts the driving parameters of the electric motor in real-time based on the detected voltage level. This feedback mechanism ensures that the output torque remains stable throughout battery discharge by compensating for voltage drops as the battery is consumed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the operating parameters of the electric motor (such as current, voltage, or rotational speed) dynamically based on the battery voltage level. By adjusting these parameters, the controller maintains consistent output torque despite the decreasing battery voltage during operation.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the battery voltage decreases during operation, then the portability and initial power output are maintained, but the consistency of torque output deteriorates

Engineering Contradiction:
ImproveportabilityVSAvoidtorque consistency
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The controller uses real-time voltage detection from the battery set to continuously adjust motor parameters, creating a closed-loop control system that maintains torque consistency despite changing battery conditions, thereby preserving both portability and performance stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static operating parameters to dynamic parameter adjustment, where the controller modifies motor driving parameters in real-time according to battery voltage changes, enabling the system to adapt and maintain stable torque output throughout the battery's discharge cycle.

Inventive Principle:
Principle #15Dynamics

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

Stabilizes the torque output of the impact tool across varying battery voltages, providing consistent performance and improved user experience.

Implementation Method 1

an electric motor including a drive shaft rotating about a first axis and outputting torque via the drive shaft; a battery set powering at least the electric motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an impact mechanism for applying an impact force to the output shaft, wherein the impact mechanism includes an impact block driven by the drive shaft and a hammer anvil impacted by the impact block

Methodology Applied
Scientific EffectMechanical impact conversion: Impact Force

Data Source

PatentEP4545251B1Impact tool
Publication Date: 2025.10.29 NANJING CHERVON IND
  • EP4545251B1 patent drawingFigure 1
  • EP4545251B1 patent drawingFigure 2
  • EP4545251B1 patent drawingFigure 3

AI summary

An impact tool (100) includes an electric motor (12); a battery set (30); an impact mechanism (15); and a controller (17). The impact mechanism (15) includes an impact block (152) and a hammer anvil (153) impacted by the impact block (152). The controller (17) is configured to: after the impact mechanism (15) applies the impact force to the output shaft (131), determine a required torque value of the electric motor (12); match a preset voltage value of the electric motor (12) in response to the required torque value; and adjust a running parameter of the electric motor (12) according to a relationship between the preset voltage value of the electric motor (12) and a current voltage value of the battery set (30) so that a difference parameter between an electric motor (12) output torque of the electric motor (12) and the required torque value is less than a preset difference parameter at each of different current voltage values of the battery set (30) .