Hand-Held Power Tool Motor Positioning for Weight Balance
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Solution Overview
Problem
Existing hand-held electric polishing or sanding power tools face challenges with space constraints, as the electric motor occupies a large portion of the rear housing, leaving limited space for other components and resulting in an uneven weight distribution.
Innovation Solution
The solution involves accommodating at least part of the electric motor in the tubular front part of the tool housing, using a slim electric motor with a smaller external diameter, and employing high-efficiency permanent magnets and a brushless motor design to compensate for the reduced torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric motor is located in the rear part of the tool housing, then sufficient torque can be provided, but the rear part becomes overweight and space for other components is limited
Solution Approach 1:
The patent divides the tool housing into two distinct parts: a rear part for gripping and control components, and a tubular front part for housing the electric motor. This segmentation allows the motor to be positioned in the front, balancing the weight distribution along the tool's length while maintaining sufficient torque output from the motor itself
Solution Approach 2:
The patent transitions from a conventional single-chamber housing to a two-part housing structure with the motor positioned in the tubular front part. This dimensional reorganization of component layout redistributes weight along the longitudinal axis of the tool, achieving better balance without compromising motor performance
2Power
If the electric motor is located in the rear part of the tool housing, then sufficient torque can be provided, but space for other components like batteries is limited
Solution Approach 1:
By segmenting the housing into rear and front parts, the patent creates dedicated space in the rear part for additional components such as batteries, electronic control units, and switches, while the front tubular part houses the electric motor
Solution Approach 2:
The electric motor is extracted from the rear part and relocated to the tubular front part of the housing. This extraction frees up valuable space in the rear housing for accommodating additional functional components that enhance the tool's capabilities
3Power
If a conventional electric motor is used, then sufficient torque is provided, but the tool housing diameter must be increased which prevents reaching tight spaces
Solution Approach 1:
The patent employs a slim electric motor design specifically tailored for the tubular front part's constrained diameter. This localized motor design maintains the necessary torque output while adapting to the narrow spatial constraints of the front housing section, enabling access to tight and cramped workspaces
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 allows for a more balanced power tool with increased space in the rear housing for additional components, such as batteries, and facilitates efficient cooling of the electric motor.
Implementation Method 1
the amount of torque which can be provided by an electric motor depends (apart from the magnetic force) on the motor's external diameter
Implementation Method 2
the rear part of the tool housing can be easily provided with venting openings allowing a cooling air stream to dissipate heat from the electric motor and other electronic components of the power tool to the environment
Data Source
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AI summary
The invention refers to a hand-held electric polishing or sanding power tool (100) comprising an elongated tool housing (16, 24, 28), in which an electric motor (23) is accommodated, and a moveable backing plate (2) protruding externally from the tool housing (16, 24, 28). The electric motor (23) is adapted to actuate the backing plate (2), the backing plate (2) thereby performing a rotational, random-orbital, orbital or gear-driven working movement in its plane of extension. A bottom surface of the backing plate (2) is adapted to detachably hold a polishing or sanding member (120). The tool housing has a rear part (24, 28) adapted and formed to be gripped by a hand of a user of the power tool (100) thereby holding the power tool (100) during its intended use and a tubular front part (16) from which the backing plate (2) protrudes, the front part (16) having a smaller diameter than the rear part (24, 28) and being attached to the rear part (24, 28). It is suggested that at least part of the electric motor (23) is accommodated in the tubular front part (16) of the tool housing.