Compact electric grinding machine

Abstract

The present invention particularly relates to a hand-held sanding machine with an outer housing (1), a tool shaft (2) and a brushless electric drive motor. In the present invention, the rotor of the drive motor is fastened to the tool shaft (2) of the sanding machine, and the stator (6) is positioned in the outer housing (1). The present invention also relates to a control method for an electric sanding machine.

Description

TECHNICAL FIELD[0001]The present invention relates to an compact electric hand-held sanding machine with an outer housing and a tool shaft.PRIOR ART[0002]Electric sanding machines of the same type are previously known from, for example, U.S. Pat. No. 0,245,182. Here, the intention has been to make a relatively compact and low sanding machine by using a brushless motor and making the proportion between the motor diameter and the motor height great. The drawback of this solution is that the motor diameter unavoidably becomes large and therefore also difficult to be gripped with one hand. Further, since the diameter is large, it becomes disadvantageous to make a hermetic motor with cooling only on the outside. This is very disadvantageous because the air in which the sanding machine is most often used is filled by dust particles that may be both electrically conductive and grinding by nature.[0003]Since electric sanding machines have previously been so large and heavy, it has been nece...

AI Technical Summary

Benefits of technology

The present invention is a compact and ergonomic sanding machine that is easy to handle with one hand. It has a low-profile design that allows for good control of grinding properties. The machine uses a brushless motor that is highly efficient and small in size. The motor is mounted in a way that allows for easy attachment to an arm or other device for two-handed operation. The machine is also designed with a hermetic structure that is insensitive to impurities in the cooling air. The invention also uses a slotless version of the motor for better efficiency and a simpler iron core design. Compared to previous tools, the present invention is much lighter and more compact, making it easier to handle and control. The Dust Extraction System is advantageous when control sensors are not present. Overall, the invention improves efficiency, space usage, and control of the sanding machine.

Problems solved by technology

The drawback of this solution is that the motor diameter unavoidably becomes large and therefore also difficult to be gripped with one hand.

Further, since the diameter is large, it becomes disadvantageous to make a hermetic motor with cooling only on the outside.

This is very disadvantageous because the air in which the sanding machine is most often used is filled by dust particles that may be both electrically conductive and grinding by nature.

Since electric sanding machines have previously been so large and heavy, it has been necessary to have special sanding machines in, for example, wall grinding.

In this way, balance has been achieved for the machine, but this also makes the machine expensive and difficult to manufacture.

The passive way requires space as well as a great volume and weight.

The drawback with the active way is that the current goes through an extra inductance L1 and is, in addition, switched one more time, because the power correction is always followed by a switched control unit.

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