Rotary Hammer Intermediate Shaft Torque Transmission
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Solution Overview
Problem
Existing rotary hammers experience efficiency losses due to unnecessary reduction and increase in rotation speeds when using two separate intermediate shafts for hammering and drilling operations, leading to inefficient power transmission.
Innovation Solution
A rotary hammer design with a motor, two intermediate shafts, and a configuration of bevel gears and gears that allow direct torque transmission from the motor to the first intermediate shaft for hammering and rotationally drive the second intermediate shaft for drilling, eliminating the need for the final output shaft in the power transmission path, thus avoiding speed reductions and increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate intermediate shafts are provided for motion-converting mechanism and rotation-transmitting mechanism, then both hammering and drilling operations can be performed, but power transmission efficiency decreases due to unnecessary reduction and increase in rotation speeds
Solution Approach 1:
The patent merges the motion-converting mechanism and rotation-transmitting mechanism into a single integrated intermediate shaft structure. The motion-converting mechanism (eccentric cam mechanism) and rotation-transmitting mechanism (gear mechanism) share the same intermediate shaft, eliminating the need for separate intermediate shafts. This integration allows direct power transmission from the motor to both mechanisms without unnecessary speed reductions and increases, thereby improving power transmission efficiency while maintaining the capability to perform both hammering and drilling operations
2Volume of moving object
If the final output shaft is located on the power transmission path between intermediate shafts, then structural compactness is achieved, but unnecessary reduction and increase in rotation speeds occurs
Solution Approach 1:
The patent extracts the final output shaft from the power transmission path between the motor and the intermediate shafts. The motor shaft directly drives the integrated intermediate shaft, and the final output shaft (spindle) is driven separately by the rotation-transmitting mechanism through gears. This extraction eliminates unnecessary speed reductions and increases in the power transmission path while maintaining structural compactness through the integrated intermediate shaft design
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 enhances power transmission efficiency by directly transmitting torque to the hammering mechanism and efficiently rotating the tool accessory for drilling, while minimizing gear engagement issues and reducing the risk of deflection.
Implementation Method 1
The motor shaft is configured to rotate a first one of the first intermediate shaft and the second intermediate shaft via a pair of bevel gears
Implementation Method 2
The first one of the first intermediate shaft and the second intermediate shaft is configured to rotate a second one of the first intermediate shaft and the second intermediate shaft via a pair of gears
Data Source
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AI summary
A rotary hammer (101) includes a spindle, a motor, a first intermediate shaft (41), a striking mechanism (6), a second intermediate shaft (42) and a rotation-transmitting mechanism (7). The motor shaft extends in a direction intersecting a driving axis. The first intermediate shaft (41) extends in parallel to the driving axis. The striking mechanism (6) converts rotation of the first intermediate shaft (41) into linear motion and linearly drives a tool accessory along the driving axis. The rotation-transmitting mechanism (7) transmits rotation of the second intermediate shaft (42) to the spindle and rotationally drives the tool accessory around the driving axis. The motor shaft rotates the first intermediate shaft (41) via a driving bevel gear and a driven bevel gear (414). The first intermediate shaft (41) rotates the second intermediate shaft (42) via a driving gear (415) and a driven gear (424).