Adjusting device for an electric motor

Patent metadata

Field	Value
Publication number	US-10033256-B2
Application number	US-201514638252-A
Country	US
Kind code	B2
Filing date	Mar 4, 2015
Priority date	Jan 24, 2009
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A device for reversing the direction of rotation and/or for adjusting the carbon brushes for a reversible electric motor, in particular for an electric hand tool, with a base and with a mount, which is mounted pivotably on the base and on which brushholders for the carbon brushes wiping over the collector of the electric motor are arranged. The electric motor can be driven by means of power electronics, such as a pulse width controller, a phase gating controller, a phase chopping controller or the like. The power electronics are arranged on the base and/or on the mount. The device furthermore has fixed contacts and switching contacts, which interact with alternate contact-making for reversing the direction of rotation of the electric motor as the mount is pivoted.

First claim

We claim:

1. A device for reversing the direction of rotation and/or for adjusting the carbon brushes for a reversible electric motor for an electric hand tool, comprising an adjusting ring having a central opening for a cooling air flow, which serves to cool the electric motor, the adjusting ring having a base, with a mount mounted pivotably on the base, switching contacts for reversing the direction of rotation of the electric motor and/or brushholders for the carbon brushes wiping over the collector of the electric motor being arranged, and the electric motor being driven by means of power electronics selected from a pulse width controller, a phase gating controller and a phase chopping controller, wherein the entire power electronics are arranged on the base and/or on the mount, with conducting fins for guiding the cooling air flow arranged on the base and/or on the mount so as to be adjacent to the central opening in the adjusting ring in such a way that the conducting fins guide the cooling air flow so as to cool the power electronics, and wherein signal processing electronics having current sensors and/or sensors for sensing a rotor position of the electric motor are arranged on the base and/or on the mount.

2. The device as claimed in claim 1 , wherein the switching contacts are configured in the form of contact blades, such that the switching contacts are located on the brushholders, which are electrically connected to the carbon brushes, such that fixed contacts, which are electrically connected to the field windings of the electric motor, are arranged on the base, and such that the fixed contacts interact with the switching contacts as mating contacts with alternate contact-making of the carbon brushes for reversing the direction of rotation of the electric motor as the mount is pivoted.

3. The device as claimed in claim 1 , wherein the power electronics have at least one power semiconductor, which switches the currents in the motor turns of the electric motor, selected from a triac, a thyristor, a MOSFET, a power diode and an H bridge, and the signal processing electronics and/or the power electronics are encapsulated, and/or cast.

4. The device as claimed in claim 1 , wherein the base and/or the mount comprises elements of the electric motor having a bearing shell for a ball bearing of the rotor shaft of the electric motor, and the base and/or the mount forms part of the housing or the supporting structure of the electric hand tool.

5. The device as claimed in claim 1 , wherein a heat sink is arranged on the base and/or on the mount for cooling the power electronics, with a thermal connection to the power semiconductor, and metallic parts of the brushholders for the carbon brushes are in the form of parts which conduct heat and/or emit heat to the air.

6. The device as claimed in claim 1 , wherein the supporting structure of the base and/or the mount consists of metal such that the supporting structure serves simultaneously to at least spread heat, to conduct heat and to emit heat to the air and/or another fluid, and the base and/or the mount is/are structured physically such that shielding for improving the EMC and/or the prevention of a flow of heat from the carbon brushes onto the heat-sensitive parts of the power electronics is enabled, and a fan for generating a cooling air flow is arranged on the base and/or on the mount for cooling the power electronics, and the fan power is subjected to open-loop and/or closed-loop control.

7. The device as claimed in claim 1 , wherein a plug for the connection to the power supply system, for the connection to the power electronics, for the connection, with mechanical and/or electrical contact, to an adjusting element with a potentiometer is arranged on the base and/or on the mount.

8. The device as claimed in claim 1 , wherein a rotary potentiometer is arranged as an adjusting element for the power electronics on the base and/or on the mount.

9. The device as claimed in claim 1 , wherein terminals of the power semiconductors in the power electronics make direct electrical and/or thermal contact with the brushholders for the carbon brushes.

10. The device as claimed in claim 1 , wherein the conducting fins for guiding the cooling air flow are arranged on the base and/or on the mount so as to be directly adjacent to the central opening in the adjusting ring.

Assignees

• Marquardt Gmbh

Inventors

• Fuchs Andreas
• Fiederer Klaus
• Girsberger Lars
• Villanova Emiliano

Classifications

• H02K11/28

  Manual switches · CPC title

• H02K23/66 Primary

  Structural association with auxiliary electric devices influencing the characteristic of, or controlling, the machine, e.g. with impedances or switches · CPC title

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title

• H02K9/04

  having means for generating a flow of cooling medium · CPC title

• H02K23/18

  having displaceable main or auxiliary brushes · CPC title