CN1867421A - Power tool - Google Patents

Abstract

The present invention relates to an electric power tool having an electric motor housed within a housing (10) and a cooling device (16, 18, 20, 30, 32). It is proposed that the cooling device (16, 18, 20, 30, 32) at least partially has a cooling channel (30) substantially closed relative to the interior cavity of the housing (10).

Description

electric machine tool

Background technique

The invention relates to an electric power tool according to the preamble of claim 1 .

In angle grinders, the cooling air required to cool the electric motor is usually drawn in via the side air inlets, which are located at the rear of the housing. It is also known to additionally provide air inlets on the rear face of the housing. In the remaining air guide section, cool air is sucked into the interior of the housing by a fan located on the armature shaft. On its way from the air inlet to the air outlet, the cool air encounters a variety of different components inside the housing that deflect, swirl and slow down the airflow.

In various electric power tools, the housing can be used as a handle, but there is a risk that the operator's hand will cover the side air inlet and air can only be sucked in through the front air inlet. These end face air inlets are relatively small compared to the side ports, so only a small amount of air reaches the housing. However, the lateral air inlets cannot be lengthened or enlarged arbitrarily, because otherwise the required distances to live parts in the housing would not be maintained.

Advantages of the invention

The invention relates to an electric power tool with an electric motor and a cooling device arranged in a housing.

It is proposed that the cooling device has at least partially a cooling channel which is substantially closed with respect to the interior of the housing. The cooling medium, preferably cooling air, can be directed past interfering components in a targeted manner. High flow rates and high volume flows can be achieved. Dirt that may be sucked in in the cooling air can be guided past sensitive parts such as brushes or switches, preventing deposits of dirt on these parts. By purposefully directing the cooling medium, the temperature on the electric motor drops, which increases its efficiency and lifetime. Precisely in highly loaded angle grinders, this design has significant advantages. Essentially closed cooling channels are to be understood in particular to also be those cooling channels which have fluidically at least largely negligible openings, such as slots, small holes or the like.

If the cooling channel enters a carrier plate of the motor housing, the cooling channel can advantageously be provided already during the manufacture of the carrier plate and can be produced in a space-saving and optimal manner in the carrier plate.

If the cooling channel is covered by a cover plate, a closed cooling channel can be provided in which the cooling medium can flow undisturbed by housing internal parts. The cooling channels can be easily cleaned when required by removing the cover plate.

A separate cover can be dispensed with if the cover is formed in one piece with a motor housing. Its production is particularly simple, and the cover plate can simply be injection-molded on when the motor housing is produced by injection molding.

If the cooling channel opens into a suction nipple protruding from the housing, it can be practically avoided that the cooling channel is inadvertently blocked by the electric power tool during operation. Furthermore, the cold air reaches directly and unhindered into the cooling duct and can be directed directly where it is needed. The cross-section of the cooling channel is variable and is set by a specialist in accordance with the requirements of the respective power tool. In principle, however, it is also conceivable that the cooling channel or the suction nipple terminates flush with the housing, in particular in an area outside the grip area, whereby dirt deposits can advantageously be avoided.

If the suction nipple is arranged on an end face of the housing, the cooling channel can be supplied with cool air unhindered, even if the housing is used as a handle.

If the cooling channel runs substantially in a straight line, the cold air reaches the electric motor unimpeded and is not obstructed by components situated in the flow path. Eddy currents rarely occur in the flow path, so that any dirt that may be carried along is less likely to settle and the cooling medium can be kept at a high velocity. A smaller inlet can be provided in order to be able to supply the required quantity of cooling medium.

A better distribution of the cooling medium supply can be achieved if at least two cooling channels are provided. The number of cooling channels is variable and is selected by professionals according to the requirements of each electric power tool. In principle, however, it is also conceivable to provide only one cooling channel.

If lateral and/or end air inlet channels are provided, additional cooling of the components inside the housing is possible without affecting the cooling of the electric motor.

It is particularly advantageous if the electric power tool is designed as an angle grinder, in which, due to principle, overloading of the drive can easily occur, which requires particularly reliable cooling.

Description of drawings

Further advantages emerge from the following description of the figures. An exemplary embodiment of the invention is shown in the drawing. The drawings, the description and the claims comprise several features in combination. A person skilled in the art can expediently examine individual features and meaningfully combine them into other combinations.

The accompanying drawings show:

Figure 1 A preferred angle grinder,

Figure 2 is a detail of a housing according to the prior art,

Figure 3 Detail of the air guide according to the prior art,

Figure 4 is a view of a carrier plate with cooling channels according to the invention,

Figure 5 Figure 4 in the cooling channel together with the cover plate,

Figure 6 The device in Figure 5 together with the switch on the assembly,

FIG. 7 An assembled housing part with suction nozzle.

Detailed ways

FIG. 1 shows an electric power tool in the form of a preferred angle grinder with an electric motor and a cooling device arranged in a housing 10 , in which a suction nipple 20 is arranged in the housing 10 on the rear end face. The angle grinder can additionally have a handle projecting at an angle from the housing 10 . The housing 10 itself also serves as a handle. The electric motor preferably drives an insert tool 12 that can be driven in rotation, such as a grinding wheel.

2 and 3 show the cold air guidance clearly according to the prior art. Identical parts are in principle marked with the same reference numerals in the figures. The housing 10 is sectioned to make the inside of the housing 10 clearer. Air drawn in by a fan (not shown) flows into the housing 10 via the lateral and end air inlets 18 , 16 . Lateral air inlets 18 can be provided on both sides of the housing 10 . After the cool air enters the housing 10, it encounters components that do not require cooling or only rarely require cooling, such as the switch 22 and the electronic device 24 . When flowing past these components 22 , 24 eddies are produced which brake the cooling air and deposit entrained dirt there. The bold arrows in the figures ( FIGS. 2 and 3 ) indicate that the cooling air has to flow around obstacles in the form of parts 22 , 24 after entering, before the cooling air reaches the interior of the motor housing 26 . Cooling air is required inside the motor housing to cool the armature and pole pieces.

The apparatus according to the invention is shown in the accompanying figures 4 to 7 below. Two cooling channels 30 enter into a carrier plate 28 of the motor housing 26 , which lead substantially straight from the two suction stubs 20 arranged in the end face 14 of the housing 10 to the motor housing 26 ( FIG. 4 ). The suction stubs 20 project beyond the housing 10 . The cooling channels 30 are covered by a cover plate 32 ( FIG. 5 ), so that gas-tight cooling channels 30 are formed. The cover plate 32 can be detachably or fixedly connected to the edge of the cooling channel 30 , for example glued, screwed or clamped on the cooling channel 30 . The cover plate 32 can be formed from a single part for all cooling channels 30 , or a separate cover plate 32 can be provided for each cooling channel 30 .

FIG. 6 shows a switch 22 which is installed in the housing on a cooling channel 30 or on a cover plate 32 . The cooling air reaches the motor housing 26 in the cooling channel 30 independently of the switch 22 .

FIG. 7 shows an assembled housing 10 with additional, end and side air inlets 16 , 18 . The suction stub 20 for the closed cooling channel 30 inside the housing 10 is arranged between a cable connection 34 and the air inlet 16 in the end face 14 of the housing 10 .

Reference number

10 shell

12 insert tool

14 end face

16 air inlet

18 air inlet

20 suction short tube

22 switch

24 electronic devices

26 Motor housing

28 load plate

30 cooling channels

32 cover

34 cable interface

Claims (10)

1. electric tools, has a motor and a cooling device (16,18,20 that is placed in the housing (10), 30,32), it is characterized by this cooling device (16,18,20,30,32) has a cooling duct (30) at least partly with respect to the inner chamber base closed of housing (10).

2. according to the described electric tools of claim 1, it is characterized by, this cooling duct (30) enter in the loading plate (28) of a motor field frame (26).

3. according to claim 1 or 2 described electric tools, it is characterized by, this cooling duct (30) are covered by a cover plate (32).

4. according to the described electric tools of claim 3, it is characterized by, cover plate (32) integrally constitutes with a motor field frame (26).

5. according to the described electric tools of one of aforementioned claim, it is characterized by, this cooling duct (30) feed in the suction short tube (20) outstanding from housing (10).

6. according to the described electric tools of claim 5, it is characterized by, this suction short tube (20) is placed on the end face (14) of housing (10).

7. according to chatting part before the claim 1 and particularly according to the described electric tools of one of aforementioned claim, it is characterized by, this cooling duct (30) basic straight line extends.

8. according to the described electric tools of one of aforementioned claim of claim, it is characterized by, at least two cooling ducts (30) are set.

9. according to the described electric tools of one of aforementioned claim of claim, it is characterized by, the air intake side and/or end face (16,18) is set.

10. the angle grinding machine has one according to the described cooling device of one of aforementioned claim of claim.

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