Metal Support for Rotary Hammer Bearings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotary hammers face challenges in maintaining positional accuracy and reducing vibration during high-power operations due to reaction forces and thermal expansion, particularly when using plastic supports for bearings and guide shafts.
Innovation Solution
The power tool incorporates a metal support for bearings and guide shafts, allowing for stronger support and reduced thermal expansion, which maintains positional accuracy and enhances vibration isolation, while also simplifying the tool structure and reducing manufacturing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If plastic supports are used for bearings and guide shafts, then weight is reduced and manufacturing is simplified, but positional accuracy deteriorates and thermal expansion increases during high-power operation
Solution Approach 1:
The patent applies different materials to different components based on their specific functional requirements. The support member is made of metal (aluminum alloy) where structural strength and positional accuracy are critical (bearing support areas), while other non-critical components can remain plastic. This localized material selection optimizes both weight and precision without unnecessary material usage throughout the entire component.
Solution Approach 2:
The support member utilizes metal alloys (specifically aluminum alloy) that combine lightweight properties with sufficient strength and low thermal expansion characteristics. This composite approach replaces heavy traditional metals with lighter aluminum alloys that maintain positional accuracy while reducing overall weight, effectively addressing both weight reduction and precision maintenance requirements.
2Productivity
If plastic supports are used for bearings and guide shafts, then manufacturing time is reduced, but vibration isolation performance deteriorates during high-power operation
Solution Approach 1:
The support member acts as an intermediary component between the housing and the intermediate shafts, providing a stable metal platform that isolates vibrations. The metal support member absorbs and dampens vibrations from the driving mechanism before they can be transmitted to the plastic housing, effectively protecting the housing from harmful vibrations while maintaining manufacturing efficiency.
3Ease of manufacture
If plastic supports are used for guide shafts, then ease of manufacture is improved, but sliding properties deteriorate due to thermal expansion during high-power operation
Solution Approach 1:
The patent changes the material parameter of the support member from plastic to metal, fundamentally altering its thermal expansion characteristics. Metal has significantly lower thermal expansion coefficients than plastic, so during high-power operation when heat is generated, the metal support member maintains its dimensional stability and does not expand excessively, thereby preserving the proper clearance and sliding properties of the guide shafts.
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
The solution enables high-power operation with reduced vibration and improved sliding properties, maintaining positional accuracy and simplifying the tool structure, thus addressing the limitations of plastic supports in rotary hammers.
Implementation Method 1
the biasing member elastically deforms and partially cushions the reaction force
Implementation Method 2
heat produced when the first guide shaft slidably guides movement of the movable support
Implementation Method 3
the support can have reduced thermal expansion compared to the case in which a plastic support is used
Data Source
AI summary
A movable support at least partially supports a final output shaft and a driving mechanism, and is integrally movable relative to a housing in an axial direction of a driving axis. A biasing member biases the movable support toward a front side in the axial direction. A first guide shaft extends in the axial direction and slidably guides the movement of the movable support in the axial direction. At least one intermediate shaft rotates in response to rotation of a motor shaft and transmit power of the motor to the driving mechanism. At least one bearing supports an end portion of the at least one intermediate shaft is located in the front side in the axial direction. A single metal support is immovable relative to the housing and supports the at least one bearing. The single metal support has a first hole for partially receiving the first guide shaft.