Spindle Locking Apparatus Positioning in Handheld Electric Tools
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Solution Overview
Problem
Handheld electric tools with spindle locking apparatuses either have a large overall length or significant tilting clearance due to the placement of the spindle locking apparatus, and they often experience noise from runout issues.
Innovation Solution
The spindle locking apparatus is positioned between the two bearing points in the tool housing, with a carrier element and spindle rollers that provide stable mounting and a brake apparatus to reduce noise from runout, allowing for a shorter tool length and reduced tilting clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spindle locking apparatus is disposed in a region downstream from the two bearing points in an axial direction of the drive spindle, then the spindle locking apparatus can be securely mounted, but the overall length of the electric tool in axial direction becomes comparatively large
Solution Approach 1:
The spindle locking apparatus is repositioned from a downstream axial location to a location between the two bearing points in the axial direction. This dimensional repositioning allows the locking apparatus to be mounted securely while significantly reducing the overall axial length of the tool, as it utilizes the space between the bearing points rather than extending beyond them.
2Length of moving object
If the spindle locking apparatus is disposed in one plane with a first bearing point that is disposed on or in the gearbox, then the overall length is shortened, but the drive spindle exhibits a comparatively large tilting clearance
Solution Approach 1:
The spindle locking apparatus is positioned between the two bearing points, which locally constrains the drive spindle in the axial direction. This localized positioning provides both length reduction and tilting clearance reduction, as the locking apparatus acts as an additional constraint point that stabilizes the spindle's position without requiring it to be co-planar with the bearing points.
3Reliability
If the drive spindle is mounted in a rolling bearing, then stable and wear-free mounting is achieved, but the carrier element mounting becomes more complex
Solution Approach 1:
A carrier element is introduced as an intermediary component between the drive spindle and the gearbox. This carrier element simplifies the mounting process by providing a standardized interface that can accommodate both the rolling bearing mounting and the spindle locking apparatus, thereby reducing overall system complexity while maintaining reliable spindle mounting.
Data Source
AI summary
In a handheld electric tool having a tool housing in which is disposed a gearbox for transferring a torque, generated by a drive motor, to a drive spindle with which a spindle locking apparatus is associated, the drive spindle being rotatably mounted in the tool housing at at least two bearing points, the at least two bearing points are provided in the tool housing in a region downstream from the gearbox, and the spindle locking apparatus is disposed between the two bearing points in an axial direction of the drive spindle.