Drill Hammer Speed Control via Acceleration Sensor
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Solution Overview
Problem
Existing drill and chisel hammers lack efficient speed control mechanisms, leading to high production and assembly costs, manufacturing tolerances, and vibration issues during idle operation.
Innovation Solution
A cost-effective solution that utilizes an acceleration sensor to determine the actual speed of the drive unit, eliminating the need for speed sensors on the fan wheel, and incorporates a control unit with algorithms for speed regulation, including Fourier analysis and phase-locked loops, to adapt the drive unit's speed based on operating states, thereby ensuring safe startup and reduced vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a speed sensor is arranged on the fan wheel to control the drive unit speed, then the speed control precision is improved, but the production costs, assembly costs, and assembly effort increase
Solution Approach 1:
The patent removes the speed sensor from the system and replaces it with an acceleration sensor that infers speed information. This extraction of the unnecessary component (speed sensor) while retaining the essential function (speed control) directly reduces device complexity and associated costs while maintaining measurement precision through alternative means.
Solution Approach 2:
The patent replaces the mechanical/electrical speed sensing system with an acceleration-based sensing system. By using an acceleration sensor to measure impact acceleration and deriving speed information from this data, the system substitutes a simpler, more cost-effective sensing mechanism while achieving the same control objective.
2Measurement precision
If a speed sensor is arranged on the fan wheel to control the drive unit speed, then the speed control precision is improved, but the manufacturing tolerances requirements increase
Solution Approach 1:
By removing the speed sensor arrangement on the fan wheel, the patent eliminates the need for precise manufacturing tolerances in that area. The acceleration sensor approach does not require the same level of manufacturing precision, thereby reducing tolerance requirements while maintaining control precision through software-based speed derivation.
3Productivity
If the drive unit operates at high speed during idle operation, then the performance of the impact unit is improved, but vibration increases
Solution Approach 1:
The patent implements dynamic speed adjustment based on operational state. The control unit monitors acceleration sensor data to distinguish between idle operation and actual drilling operation, dynamically adjusting the drive unit speed accordingly. This allows high speed during active drilling for performance while reducing speed during idle periods to minimize vibration, creating an adaptive system that optimizes both productivity and reduces harmful effects.
Solution Approach 2:
The patent employs feedback control where the acceleration sensor continuously monitors the operational state and provides information to the control unit. Based on this feedback, the control unit adjusts the drive unit speed in real-time, reducing speed when idle conditions are detected to minimize vibration while maintaining high speed when drilling operations are active to ensure performance.
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 approach reduces production and assembly costs, enables precise speed control, and minimizes vibration during idle operation, enhancing the performance and efficiency of the percussion unit.
Implementation Method 1
the sensor element designed as an acceleration sensor is provided to record acceleration values dependent on the impact mechanism unit
Implementation Method 2
the control or regulating unit is at least provided to adjust a speed of the drive unit depending on a signal from the sensor element designed as an acceleration sensor
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a machine tool device, in particular a handheld machine tool device, comprising at least one control and/or regulating unit (12a; 12b) for controlling and/or regulating a drive unit (14a; 14b) and comprising at least one sensor unit (16a; 16b) which comprises at least one sensor element (18a; 18b) designed as an acceleration sensor. The control and/or regulating unit (12a; 12b) is provided at least for determining at least one actual rotational speed of the drive unit (14a; 14b) from a signal of the sensor element (18a; 18b) designed as an acceleration sensor.