Rotary Hammer Drive Split for Independent Speed and Impact Control
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Solution Overview
Problem
Existing rotary hammers lack the ability to independently control the reciprocation frequency of the piston and rotation speed of the spindle, limiting the versatility and efficiency of axial impacts on tool bits.
Innovation Solution
A rotary hammer design incorporating two motors, one for rotating the spindle and another for reciprocating the piston, with a variable pressure air spring mechanism and multi-speed transmissions, allowing independent adjustment of reciprocation frequency and rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor is used to drive both spindle rotation and piston reciprocation, then the device complexity is reduced, but the ability to independently control reciprocation frequency and rotation speed is lost
Solution Approach 1:
The patent divides the drive system into two separate motors: a first motor dedicated to driving spindle rotation and a second motor dedicated to driving piston reciprocation. This segmentation allows independent control of rotational speed and reciprocation frequency, resolving the contradiction between device simplicity and control versatility.
Solution Approach 2:
The patent implements dynamic control by allowing the controller to independently adjust the speed of the first motor (affecting spindle rotation) and the second motor (affecting piston reciprocation). This dynamic independence enables adaptive optimization of drilling parameters for different materials and applications.
2Device complexity
If reciprocation frequency and rotation speed are coupled, then the control system is simpler, but the optimization of drilling performance is limited
Solution Approach 1:
The control system is segmented into two independent control channels: one for regulating the first motor's speed (spindle rotation) and another for regulating the second motor's speed (piston reciprocation). This segmentation enables independent optimization of both parameters to maximize drilling efficiency for different rock types and drill bit configurations.
Solution Approach 2:
The patent enables independent variation of critical parameters (rotational speed and reciprocation frequency) to optimize drilling performance. The controller can adjust these parameters based on drilling conditions, material hardness, and tool wear, thereby improving productivity without oversimplifying the control system.
3Adaptability or versatility
If two separate motors are used for spindle rotation and piston reciprocation, then independent control of rotation speed and reciprocation frequency is achieved, but the device complexity increases
Solution Approach 1:
The controller serves multiple functions: it controls both motors, manages power distribution, monitors operational parameters, and adjusts settings in real-time. This multi-functionality consolidates control complexity into a single intelligent unit, offsetting the mechanical complexity of having two motors.
Solution Approach 2:
The patent replaces complex mechanical coupling mechanisms with electronic control. Instead of using mechanical linkages to couple the two motors, the system uses electronic controllers to independently regulate each motor's output, simplifying the mechanical structure while maintaining independent control capability.
4Device complexity
If the piston reciprocation is directly coupled to spindle rotation, then the mechanism is simpler, but the ability to create variable pressure air spring is reduced
Solution Approach 1:
The patent makes the reciprocation mechanism dynamic by using a second motor to independently control piston reciprocation speed and frequency. This dynamic control enables the creation of a variable pressure air spring, where the air pressure in the annular space varies during the reciprocation cycle, improving impact consistency and reducing mechanical wear.
Solution Approach 2:
The patent introduces a pneumatic element (air spring) into the reciprocation mechanism. The variable pressure air spring acts as a cushion and energy storage medium, smoothing out pressure fluctuations and improving the reliability of axial impacts on the tool bit while allowing for more complex reciprocation control.
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
Enables precise control over the blow pattern of the tool bit, optimizing drilling speed and efficiency by separating the control of rotational speed and reciprocation frequency, enhancing operational flexibility and performance.
Implementation Method 1
a reciprocation mechanism operable to create a variable pressure air spring within the spindle
Data Source
AI summary
A rotary hammer includes a motor and a spindle coupled to the motor for receiving torque from the motor. The spindle has an adjustable rotation speed. A reciprocation mechanism is operable to create a variable pressure air spring within the spindle and includes a piston configured to reciprocate within the spindle in response to receiving torque from the motor. The piston has an adjustable reciprocation frequency. A striker is selectively reciprocable within the spindle in response to reciprocation of the piston. A first transmission is transfers torque from the motor to the spindle and a second transmission is transfers torque from the motor to the reciprocation mechanism. The reciprocation frequency of the piston is adjustable independent of the rotation speed of the spindle. The rotation speed of the spindle is adjustable independent of the reciprocation frequency of the piston. At least one of the transmissions is a multi-speed transmission.