Coil spacing

US11110581B2 · kind B2 · utility

Assignee

• Hilti Aktiengesellschaft · LI

Inventors

• Konrad Artmann · Schondorf am Ammersee, DE
• Thomas Schaefer · Trier, DE
• Markus Hartmann · Mauerstetten, DE
• Norbert Daam · Oberdießen, DE

Key dates

• Filing date: Nov 9, 2017
• Grant date: Sep 7, 2021
• Expiry date: Feb 23, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02K2213/03
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A power tool (1) is provided, especially a hammer drill and/or a chiseling hammer drill, including a percussive mechanism (12) with a percussive element (13) to generate a percussive pulse onto a tool (1), the element being reversibly movable along a longitudinal axis (R) by a magnetic field in order to generate the percussive pulse, and including at least a first and a second coil device (1, 2) to generate the magnetic field. Each coil device (1, 2) has at least a first coil ring (3) with a first radius (R1) and a second coil ring (4) with a second radius (R2), whereby the first radius (R1) of the first coil ring (3) is greater than the second radius (R2) of the second coil ring (4), so that a space (S) is formed, at least in certain areas, between the at least first and second coil rings (3, 4), whereby a fluid (L), especially an air stream, that serves to cool the coil device (1, 2) can flow through the space.