Hand-Held Power Tool Housing Decoupling for Vibration Reduction
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Solution Overview
Problem
Existing hand-held power tools experience significant vibrations due to rotational oscillations, which are not effectively decoupled from the handles, leading to uncomfortable operation.
Innovation Solution
The implementation of a decoupling system with a first support device adjacent to the center of gravity, allowing the cover housing to move axially and pivotally, combined with a spring device and a second support device with higher rotational stiffness, effectively decouples vibrations along both axes, providing stable support and reduced vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cover housing is held flexibly on the base housing with articulation points, then the handle can move relative to the housing, but rotational oscillations are still transmitted to the handle because the resilient material expands only slightly in the rotating direction
Solution Approach 1:
The decoupling system is divided into multiple independent support devices: a first support device for axial displacement and a second support device for rotational oscillations. This segmentation allows each device to specialize in blocking specific vibration directions, with the second support device specifically designed to prevent rotational oscillation transmission while the first allows axial movement.
Solution Approach 2:
Different support devices are positioned at specific locations relative to the center of gravity to provide direction-specific decoupling. The first support device is located to enable axial displacement, while the second support device is positioned to resist rotational oscillations. This local differentiation of support characteristics addresses the directional dependency of vibration transmission.
2Loss of energy
If the resiliently flexible material is used at articulation points, then some vibration damping is achieved, but the material's small expansion in the rotating direction results in insufficient decoupling of rotational oscillations
Solution Approach 1:
A second support device acts as an intermediary element specifically for rotational oscillations. This additional support device mediates the rotational movement by providing a dedicated path that allows rotational decoupling while maintaining structural integrity. It works in conjunction with the resilient material but adds specific rotational resistance to the decoupling system.
Solution Approach 2:
The system uses dynamic characteristics of different support devices: the first support device allows dynamic axial displacement to accommodate handle movement, while the second support device provides dynamic resistance to rotational oscillations. This dynamic differentiation enables the system to respond appropriately to different types of vibration based on their direction and nature.
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 significantly reduces vibrations transmitted to the handles, enhancing the comfort and stability of the hand-held power tool during operation by actively decoupling axial and rotational oscillations.
Implementation Method 1
a spring device (20; 20') which supports the cover housing (18) for displacement in a direction of the first spatial axis (z)
Implementation Method 2
Depending on the spring means that is used, there is also provided a damping effect to a degree
Implementation Method 3
The cover housing (18) can be displaced substantially parallel to the first spatial axis (z) and is also pivotable in direction of the first spatial axis by means of the first support device (19)
Implementation Method 4
a respective shell-side pin engages in a housing-side sleeve with the intermediary of a resiliently flexible material
Data Source
AI summary
A hand-held power tool (2) has a base housing (4) in which there is provided an operational unit (12) movable in a reciprocating manner along a operational axis (A) defining a first spatial axis (z) and spaced from a center of gravity (SP) of the hand-held power tool (2) in direction of a second spatial axis (y) which is perpendicular to the first spatial axis, (z), and further has a cover housing (18) which is held on the base housing (4) by decoupling elements and is fixedly connected to a main handle (24) and to side-handle connection element (28), with the decoupling elements having, in a projection perpendicular to a plane (Eyz) defined by the first spatial axis (z) and the second spatial axis (y), a first support device (19) which is located adjacent to the center of gravity and which holds the cover housing (18) on the base housing (4) so as to be displaceable along and pivotal in direction of the first spatial axis (z).