Hand guided and/or hand held electric or pneumatic power tool

Patent metadata

Field	Value
Publication number	US-11325238-B2
Application number	US-201816223769-A
Country	US
Kind code	B2
Filing date	Dec 18, 2018
Priority date	Dec 21, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

The invention refers to a hand guided and/or hand held electric or pneumatic power tool (1, 1′), comprising an electric or pneumatic motor (15, 100), a working element (9) realizing a working movement (11), when the motor (15, 100) is activated, and at least one gear arrangement functionally located between the motor (15, 100) and the working element (9) for transmitting a rotational movement and torque from the motor (15, 100) to the working element (9) in order to realize the working movement (11). It is suggested that the at least one gear arrangement is embodied as a magnetic gear arrangement (20, 21, 41) using magnetic fields to transmit the rotational movement and torque from the motor (15, 100) to the working element (9) without mechanical contact, in order to realize the working movement (11).

First claim

The invention claimed is:

1. A hand held electric or pneumatic power tool in the form of a sander or a polisher, comprising an electric or pneumatic motor, a working element in the form of a backing pad, realizing a roto-orbital or a random orbital working movement, when the electric or pneumatic motor is activated, and at least one coaxial magnetic gear arrangement functionally located between the electric or pneumatic motor and the working element for transmitting a rotational movement and torque from the electric or pneumatic motor to the working element in order to realize the working movement, wherein the at least one coaxial magnetic gear arrangement has three principle coaxial components, all three of which may rotate relative to each other about a common rotational axis, the three principle coaxial components having
a first component with a first number of permanent magnets arranged in magnetic pole pairs that generates a first magnetic field,
a second component with a second number of permanent magnets arranged in magnetic pole pairs that generates a second magnetic field, and
a radially intermediate third component with a non-magnetic structure carrying a third number of ferromagnetic pole pieces that acts as a passive part of a magnetic circuit between the first component and the second component.

2. The power tool of claim 1 , wherein the first number of pole pairs of the first component is smaller than the second number of pole pairs of the second component.

3. The power tool of claim 2 , wherein the first component is an inner component connected to a shaft of the electric or pneumatic motor.

4. The power tool of claim 1 , wherein the electric or pneumatic motor is an electric motor comprising a stator with electrical windings and a rotor with magnetic pole pairs, wherein the first component of the at least one magnetic gear arrangement is formed by the rotor of the electric motor, and wherein the magnetic pole pairs of the rotor of the electric motor also act as the magnetic pole pairs of the first component of the at least one magnetic gear arrangement.

5. The power tool of claim 4 , wherein the second component or the radially intermediate third component of the at least one magnetic gear arrangement is connected to the stator of the electric motor in a torque proof manner.

6. The power tool of claim 5 , wherein the third component or the second component of the at least one magnetic gear arrangement, which is not connected to the stator of the electric motor, is connected to a tool shaft of the power tool, which is directly or indirectly connected to the working element, or to an intermediate shaft of the power tool, which is directly or indirectly connected to the tool shaft.

7. The power tool of claim 2 , wherein the electric or pneumatic motor is an electric motor comprising a stator with electrical windings and a rotor with magnetic pole pairs, wherein the first component of the at least one magnetic gear arrangement is formed by the rotor of the electric motor, and wherein the magnetic pole pairs of the rotor of the electric motor also act as the magnetic pole pairs of the first component of the magnetic gear arrangement.

8. The power tool of claim 2 , wherein the electric or pneumatic motor is an electric motor; and the second component of the at least one magnetic gear arrangement is located radially outside the radially intermediate third component of the at least one magnetic gear arrangement and is provided with electrical windings located radially outside of the magnetic pole pairs, in order to form or make part of an outer stator of the electric motor, wherein the first component of the at least one magnetic gear arrangement is located radially inside the radially intermediate third component and forms or makes part of an inner rotor of the electric motor and wherein the outer second component and the third intermediate component are located between the windings and the inner first component.

9. The power tool of claim 2 , wherein the electric or pneumatic motor is an electric motor; and the first component of the at least one magnetic gear arrangement is located radially outside the radially intermediate third component of the at least one magnetic gear arrangement and forms or makes part of an outer rotor of the electric motor, wherein the second component of the magnetic gear arrangement is located radially inside the radially intermediate third component of the at least one magnetic gear arrangement and wherein the inner first component or the third intermediate component is provided with electrical windings in order to form or make part of an inner stator of the electric motor.

10. The power tool of claim 2 , wherein the first component comprises a first number (n_input) of permanent magnets, the second component comprises a second number (n_output) of permanent magnets, wherein the first number (n_input) of permanent magnets and the second number (n_output) of permanent magnets are even numbers, and wherein the gear ratio (i) of the at least one magnetic gear arrangement is i=n_output/n_input.

11. The power tool of claim 1 , wherein the electric or pneumatic motor is an electric motor; and the second component of the magnetic gear arrangement is located radially outside the radially intermediate third component of the magnetic gear arrangement and is provided with electrical windings located radially outside of the magnetic pole pairs, in order to form or make part of an outer stator of the electric motor, wherein the first component of the magnetic gear arrangement is located radially inside the radially intermediate third component and forms or makes part of an inner rotor of the electric motor and wherein the outer second component and the third intermediate component are located between the windings and the inner first component.

12. The power tool of claim 1 , wherein the electric or pneumatic motor is an electric motor; and the first component of the at least one magnetic gear arrangement is located radially outside the radially intermediate third component of the magnetic gear arrangement and forms or makes part of an outer rotor of the electric motor, wherein the second component of the at least one magnetic gear arrangement is located radially inside the radially intermediate third component of the at least one magnetic gear arrangement and wherein the inner first component or the third intermediate component is provided with electrical windings in order to form or make part of an inner stator of the electric motor.

13. The power tool of claim 1 , wherein the at least one magnetic gear arrangement is located within a closed housing, with at least an output shaft of the at least one magnetic gear arrangement, which is connected in a torque proof manner to the working element, emerging from the housing through a throughway opening.

14. The power tool of claim 1 , wherein the first component comprises a first number (n_input) of permanent magnets , the second component comprises a second number (n_output) of permanent magnets , wherein the first number (n_input) of permanent magnets and the second number (n_output) of permanent magnets are even numbers, and wherein the gear ratio (i) of the at least one magnetic gear arrangement is i=n_output/n_input.

15. The power tool of claim 1 , wherein the radially intermediate third component comprises a third number (n_pp) of ferromagnetic pole pieces, which is either n_pp=(n_output-n_input) or n_pp=(n_output+n_input).

16. The power tool of claim 1 , wherein the non-magnetic structure comprises a non-magnetic and non-conductive structure

Assignees

• Valentini Guido

Inventors

• Valentini Guido

Classifications

• B25F5/001 Primary

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• Y02E10/72

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• H02K49/102

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