DE102007039550A1 - Electric motor i.e. direct current motor, for use in electric hand tool device, has bearing bracket and stator including protrusion, which engages into recess of another bearing bracket and stator in assembled condition of bearing bracket - Google Patents

Abstract

The motor has a commutator, a stator and a rotor for driving a drive shaft. A cup shaped bearing bracket (10) is provided for storage of the drive shaft. The bearing bracket is made of plastic and fixed at the stator. The bearing bracket and the stator have a protrusion (26), which engages in a recess of another bearing bracket and stator in an assembled condition of the bearing bracket in a locking manner. The protrusion has a profile of harpoon. The bearing bracket is provided at the stator in the commutator side.

Description

The The invention relates to an electric motor, in particular for an electric hand tool device with a stator and a arranged therein rotor for driving a drive shaft and a Collector and with at least one bearing bracket for storage of Drive shaft.

Such electric motors are known in the art. For example, the DE 37 44 488 A1 a universal electric motor for any drive refer to a stator with stator windings and a rotatably mounted anchor with collector and brush holders and carbon brushes and both sides of the bearing for the armature shaft forming end shields, the end shields are here bow-shaped and are connected to the stator by inserting into grooves , The bearing brackets are made of a stamped sheet and with appropriate thickness and provided with ribbing.

However, such a configuration is in an electric hand tool device, in particular according to the requirements of the protection class II DIN EN 61140 (VDE 0140-1) for electric hand tool devices should be sufficient, not operational, since due to the requirements of the electrical insulation, the use of uninsulated sheet metal brackets is out of the question. In addition, bearing brackets or end shields are known which can receive the drive shaft from both sides and can be screwed to the stator, wherein also the end shields are formed of uninsulated metal.

Based on the cited prior art, it should now be an object of the invention to provide an electric motor which meets the requirements of protection class II DIN EN 61140 fulfilled and at the same time with sufficient stability for a beating tool as easy to assemble.

The Invention solves this problem by an electric motor of generic type, in which the bearing bracket is made of plastic and can be fixed to the stator, wherein the bearing bracket and / or the stator has at least one projection which is mounted in a Position of the bearing bracket in at least one recess engages the respective other component latching. By Providence the bearing bracket made of plastic, wherein the bearing bracket in particular can be made as an injection molded part, the requirements to a protection class II engine in terms of insulation for Electric hand tool devices particularly easy fulfilled become. Due to the locking of the two components together the assembly is much easier.

It can be provided that if the bearing bracket is provided on the collector side, the bearing bracket at least a receptacle for one or more carbon brush holder or carbon brushes.

Especially Preferably, it can be provided that the projection at least one Harpoon profile, which then has an opening for example, in the stator passes through and against an edge of the opening to come to rest.

Especially Preferably, it is provided that the bearing bracket a cup-like Basic form has, so a rotationally symmetrical, unilaterally open basic shape, so that the largest possible contact area with the stator is created. The lateral surface can thereby be frustoconical or cylindrical with respect to the basic shape.

there can be particularly preferably provided that the bearing bracket and / or stator webs, which at their free ends a harpoon profile possess, more preferably provided two or more webs can be equidistant over the Circumference of a substantially cup-shaped bearing bracket or the stator can be arranged distributed. About that In addition, it can be provided that in addition to the webs, which have the projections, for locking with the stator or the bearing bracket more Webs are provided which are arranged in particular on the bearing bracket are and with which the bearing bracket then over his Circumference against the circumference, in particular the inner circumference of the stator abuts, the bearing bracket for this purpose with its webs in a pointing in the direction of the bearing bracket opening of the stator is inserted, so that the projections of the Pass through the stator from the inside out. You can do this the webs are elastically deformed and the, the projections supporting webs can also be in the mounted position Rest stop mentioned called rebound, whereas the other bars remain deformed to a certain extent and so a radial tension between the components, bearing bracket and stator generate. The webs can be separated from each other by open-edge slots be. In this case, the webs, the projections and preferably the webs without projections alternately be arranged.

It may be provided that the webs, no projections wear, are designed so that they are biased against the Scope of the other component, in particular the stator abut and so as to be able to absorb in particular radial forces. In addition, it can be provided that on the bearing bracket or on the stator a stop is provided, the insertion of the Components in each other in particular of the bearing bracket in the Stator limited.

Of Furthermore, it can be provided according to the invention a spring element is provided between the stator and the bearing bracket is, so in the locked state between bearing bracket and stator an axial tension prevails, so that a backlash-free Attachment of the bearing bracket is provided on the stator.

By the distribution of the projections on the bearing bracket or on the stator and the corresponding arrangement of the openings, in which the projections can intervene, can at the same time against rotation of the bearing bracket be assured of the stator. A joining is about it Be possible only in predetermined positions, the Arrangement can be made so that only a single position when joining is possible so as to make mistakes in the Assembly continues to reduce. In addition, you can the webs, which have no projections, and against a Abut peripheral wall of the other component, at the same time as a centering aid serve during assembly.

When Spring element, which ensures the axial bias can hereby an O-ring can be used, especially before the joining process in the axial direction on the webs of the stator or the bearing bracket is pushed and then together with the bearing bracket by axial pushing on the stator or insertion placed in the stator in its position. The diameter of the O-rings is to be chosen so that a sufficient axial preload ensured between bearing bracket and stator is, but at the same time a joining still possible is.

Provided a stop on the bearing bracket or provided on the stator is, the O-ring can initially against the stop to the plant are brought before the joining process.

A radial prestressing can be achieved via the spring forces the webs and in particular not the axial fixation serving webs, in particular of the plastic bearing bracket occur themselves, with the webs by the elastic properties the plastic during the joining process resiliently radially inwards can deform and so a bias between the two Able to provide components in the mounted position.

at the motor may in particular be a DC motor, as he especially in electrical hand tool devices such as Drills, rotary hammers, impact drills, etc. used becomes.

By the embodiment described above, the collector then taken in the bearing bracket, with the carbon brushes of the collector with its brush holders in the bearing bracket can be kept and in particular also the strands for Connection with the carbon brushes fixed to the bearing bracket could be.

After all The invention also relates to an electric hand tool device with an electric motor according to the invention.

Further Advantages and features of the invention will become apparent from the others Application documents. The invention will be described below with reference to a drawing explained in more detail. Showing:

1 a first representation of the bearing bracket;

2 one at 90 ° 1 rotated representation of the bearing bracket;

3 one opposite 1 rotated by 45 ° representation of the bearing bracket;

4 a view of the bearing bracket from the collector side thereof;

5 an illustration of the bearing bracket from the stator side thereof;

6 a three-dimensional representation of the bearing bracket;

7 a view of the bearing bracket connected to the stator;

8th a sectional view according to 7 and

9 a half-cut view of a bearing bracket connected to the stator, the 45 ° opposite 7 is shown rotated.

1 shows a bearing bracket, in its entirety by the reference numeral 10 is provided. The bearing bracket is a plastic part that can be manufactured by injection molding.

The bearing bracket 10 has a cup-shaped basic shape with a cup bottom 12 and a cup opening 14 , wherein the cup opening 14 in the installed position facing a stator of an electric motor of an electric hand tool device.

In the area of the side walls, holders for the carbon holders are provided on two diametrically opposite areas, which then carry the carbon brushes 16 Wear, these with strands 18 can be connected.

On the opening 14 facing side of the bearing bracket 10 This is with two different types of bars 20 and 22 equipped, with the bearing bracket 10 with these webs, as will be shown later, are inserted into a stator, wherein the webs 20 . 22 are formed radially resilient and the webs 20 and 22 through over part of the longitudinal direction 24 of the bearing bracket 10 extending to the edge of the bearing bracket 10 open slots are separated from each other so that the webs 20 . 22 have free end portions that assign towards the stator in the mounted position and are movable relative to each other.

Here, the webs carry 20 at its free end projections 26 , which are harpoon-shaped and can be snapped into corresponding openings of a stator. There are four bars here 20 with projections 26 provided, which equidistant over the circumference of the bearing bracket 10 are arranged, as well as four bars 22 , which are also distributed equidistantly and between the jetties 20 extend. The extent of the bridges 20 . 22 in the circumferential direction can be adjusted depending on the expected forces. In the present case, the webs own 22 a greater extent in the circumferential direction than the webs 22 , The bridges 22 do not have a ledge at their free end and are around the area of the ledge 26 in the axial direction 24 shorter than the webs 20 , Task of the webs 22 is to abut against an inner wall of the stator and so to center the bearing bracket and absorb radial forces by the webs 22 support against the inner wall of the stator.

Thus, the webs take 20 axial and the webs 22 the resulting radial forces.

In addition, the webs carry 22 attacks 28 , which is a defined piece of the free or open end of the bearing bracket 10 are spaced and the axial insertion of the bearing bracket 10 in a stator limit. The stator then comes against the stop 28 to lie.

The bearing bracket 10 serves to receive the bearing of the drive shaft (not shown), which is driven by an electric motor, in particular a DC motor of a power hand tool device comprising a stator and a rotor. In addition, the bearing bracket carries 10 in the embodiment of the invention, the carbon brushes 16 which cooperate with the commutator or collector (not shown).

Due to its design as a plastic component is achieved that when using the bearing bracket 10 In an electric hand tool, the requirements of the protection class II for electric hand tools can be achieved.

2 now shows a representation according to 1 in a 90 ° rotated arrangement, so now the carbon brushes 16 on both sides of the bearing bracket 10 appear.

On the other hand shows 3 a 45 ° rotated arrangement to the 1 and 2 ,

In the 4 and 5 taking a view from both the ground 12 as well as from the opening 14 of the bearing bracket 10 can show the equidistant distribution of the webs 20 and 22 over the circumference of the bearing bracket 10 and their respective extent in the circumferential direction can be seen.

By the axial fixing by means of the projections 26 in a stator and the radial support by means of the webs 22 On an inner surface of the stator static and dynamic loads can be taken sufficiently stable, so that the requirements for stability for a beating electric hand tool device can be satisfied. It is particularly advantageous that by the provision of the various webs 20 and 22 the radial and the axial fixation are decoupled, so that each of the webs 20 and 22 can be optimized for the loads to be absorbed and the loads per bridge are limited.

7 now shows a representation in which the bearing bracket 10 with a stator 30 in particular a stator housing 32 comprises, is joined, wherein the bearing bracket 10 in the axial direction 34 in the case 32 of the stator 30 is inserted. The bridges 22 lie against an inner surface of the housing 32 on, as in 8th shown.

The housing 32 of the stator 30 also has openings 36 on that through the protrusions 26 of the bridges 20 be taken through and thus provide an axial fixation. For this purpose, the bridges are in the joining 20 resiliently deformed and spring back again as soon as the projections 20 in the openings 36 can intervene. In order to ensure an axial play-free determination, moreover, designed as an O-ring spring element 38 provided between the housing 32 of the stator and the projections 28 at the footbridges 22 are provided, is inserted and is pressed together during the joining process, so that a play-free axial connection of bearing bracket 10 and stator 30 given is.

The radial fixing takes place by the webs 22 also due to the slots 40 between the bridges 22 and 20 can move resiliently and be deformed by a certain amount during the joining process radially inwards, so that the webs 22 free from play against the inner wall of the Ge häuses 32 of the stator 30 issue.

By the providence of the projections 26 on the bearing bracket 10 as well as the recesses 36 on the housing 32 of the stator 30 that match the size of the protrusions 26 Correspond in the circumferential direction, in addition, a rotation can be ensured during installation, where appropriate, by design of the projections 26 as well as the corresponding openings 36 Also, a specific installation position can be specified.

9 now shows a half-cut representation, which compared to the representations according to 7 and according to 8th rotated by 45 °, so here is the rear locking of the projections 26 behind an edge of the recess 36 in the case 32 of the stator 30 can be seen, with the projections 26 the edge of the openings 36 engage behind and formed by the spring element through the O-ring 36 a tension of the components bearing bracket 10 and stator 30 to each other, so that unintentional release of the two components is avoided from each other, even under dynamic loads, as they can occur especially in a beating operating state of a power hand tool.

In the manner described above, a bearing bracket 10 be provided in particular for a DC motor of an electric hand tool device, wherein the bearing bracket 10 consists of a plastic and thus provides a high stability against static and dynamic loads at low cost and easy installation.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3744488 A1 [0002]

Cited non-patent literature

• - DIN EN 61140 [0003]
• - DIN EN 61140 [0004]

Claims (13)

Electric motor with a stator ( 30 ) and a rotor arranged therein for driving a drive shaft and a collector and with at least one bearing bracket ( 10 ) for supporting the drive shaft, characterized in that the bearing bracket ( 10 ) consists of plastic and on the stator ( 30 ), wherein the bearing bracket ( 10 ) and / or the stator ( 30 ) at least one projection ( 26 ), which in an assembled position of the bearing bracket ( 10 ) in at least one recess ( 36 ) of the respective other component ( 10 . 30 ) engaging latching. Electric motor according to claim 1, characterized in that the bearing bracket ( 10 ) on the collector side at the stator ( 30 ) is provided. Electric motor according to claim 2, characterized in that the bearing bracket ( 10 ) at least one receptacle for one or more carbon brush holders or carbon brushes ( 16 ) having. Electric motor according to claim 1, characterized in that the at least one projection ( 26 ) have a harpoon profile. Electric motor according to claim 1 or 2, characterized in that between bearing bracket ( 10 ) and stator ( 30 ) at least one spring element ( 38 ), in particular an O-ring, is provided which an axial tension between bearing bracket ( 10 ) and stator ( 30 ) generated in a mounted position. Electric motor according to one of the preceding claims, characterized in that the bearing bracket ( 10 ) and / or the stator ( 30 ) have at least one spring element, which has the at least one projection ( 26 ) radially resiliently on the bearing bracket ( 10 ) and / or stator ( 30 ). Electric motor according to claim 6, characterized in that the spring element by at least one by open-edge axial slots ( 40 ) in the bearing bracket ( 10 ) and / or in the stator ( 30 ) limited axial web ( 20 ), wherein the at least one projection ( 26 ) at a free end of the bridge ( 20 ) is arranged. Electric motor according to one of the preceding claims, characterized on the bearing bracket ( 10 ) and / or on the stator ( 30 ) at least one further bridge ( 22 ) is formed, which in an assembled position with its peripheral surface against a corresponding peripheral surface of the other component ( 10 . 30 ) is applied under radial tension for receiving radial forces. Electric motor according to claim 8, characterized in that the bearing bracket with the webs ( 20 . 22 ) in the stator ( 30 ), in particular a housing ( 32 ) of the stator ( 30 ) can be inserted. Electric motor according to one of the preceding claims, characterized in that the bearing bracket ( 10 ) is cup-shaped. Electric motor according to claim 10, characterized in that the webs ( 20 . 22 ) starting from an open end of the cup-shaped bearing bracket ( 10 ) in its longitudinal direction ( 24 ). Electric motor according to one of the preceding claims, characterized in that the electric motor is a DC motor is. Electric hand tool with an electric motor according to any one of claims 1-12.