DE102014205563A1 - Hand-operated machine tool - Google Patents

Abstract

The invention relates to a hand-held machine tool (1) for driving a tool, comprising: - a housing (2); - One in the housing (2) received rotary drive motor (3); - an elastic bearing (8) disposed on the drive motor (3) for supporting the drive motor (3) on the housing (2) in a radial direction; and - a radial bearing (9) which is designed to torque-tightly couple and axially decouple a drive shaft (4) of the drive motor (3) and a driven-side shaft.

Description

Technical area

The invention relates generally to the field of hand-held machine tools, in particular rotary hammers and the like, in which a tool is moved by means of an electric drive motor which is torque-effectively coupled to the tool.

State of the art

There are generally known electric tools in which a drive motor via a fixed / movable bearing combination, for. B. in the form of deep groove ball bearings, is stored. Furthermore, for example, from the DE 10 2008 063 510 A1 a hand-held machine tool known, wherein the drive motor and a transmission device are mounted floating in a housing device, wherein the drive motor and the transmission device are spatially separated from each other and connected to each other via a shaft.

Usually, the designs of drive motors for use in hand-held machine tools have significant tolerances that can occur both in the axial and in the radial direction. The housing shells into which the drive motor is used during assembly, may have structural tolerances, as these z. B. may be formed as injection molded parts. Basically, therefore, measures are usually necessary to compensate for the structural tolerances between the inclusion in the housing shell and the drive motor to be used, since in particular the housing is formed of a hard plastic material that does not allow a compression of the drive motor in the housing shell.

It is an object of the present invention to provide a bearing for a drive unit of a hand-held machine tool, which has an improved tolerance compensation for the drive motor in the radial and axial directions.

Disclosure of the invention

This object is achieved by the hand-held machine tool according to claim 1.

• – ein Gehäuse;
• – einen in dem Gehäuse aufgenommenen rotatorischen Antriebsmotor;
• – ein an dem Antriebsmotor angeordnetes elastisches Lager, um den Antriebsmotor an dem Gehäuse in einer radialen Richtung abzustützen; und
• – ein Radiallager, das ausgebildet ist, um eine Antriebswelle des Antriebsmotors und eine abtriebsseitige Welle drehmomentfest zu koppeln und axial zu entkoppeln.

Further embodiments are specified in the dependent claims. According to one aspect, there is provided a hand-held machine tool for driving a tool, comprising:

• A housing;
• - A received in the housing rotary drive motor;
• An elastic bearing disposed on the drive motor for supporting the drive motor on the housing in a radial direction; and
• - A radial bearing, which is adapted to a drive shaft of the drive motor and a driven shaft to couple torque-tight and axially decouple.

One idea of the above hand-held machine tool is to float the drive motor with a radial bearing and an axially offset, not fixed in its position, elastic bearing within a receiving area. As a result, a bearing of the drive motor can be provided, which allows compensation of radial and axial structural tolerances.

The elastic bearing provides for a bearing of the drive motor in the radial direction and allows a positive connection with the housing of the machine tool. The elastic bearing is configured to radially support and center the drive motor with respect to the desired position of its drive shaft. In contrast, the elastic bearing can absorb axial forces only to a small extent, so that the drive motor floats with respect to the elastic bearing.

For torque-resistant connection of the drive motor with a driven-side shaft, for coupling with a gear, z. B. the hammer mechanism for a hammer drill, serves, a radial bearing can be provided. The radial bearing has a slidable in the axial direction positive connection between a position of a drive shaft of the drive motor and the transmission shaft, which allows a recording of torques. As a result, no force is transmitted in the axial direction via the radial bearing. Thus, also coaxial deviations between the elastic bearing, which allows a floating recording of the drive motor, and the radial bearing in the drive pinion can be compensated.

In the axial direction, the drive motor can continue to be held by two floating bearings, which allow free positioning of the drive motor within a range of motion. This makes it possible to use the drive motor in the housing of the hand-held machine tool, without an absolutely defined position of the drive motor is provided. The drive motor is thus self-aligning during installation or during operation.

Furthermore, the radial bearing may have a positive locking cylinder which is axially slidably received in a recess of the output-side shaft.

In particular, the positive locking cylinder of the radial bearing may have a non-round cross-section, wherein the recess of the output-side shaft has a corresponding cross section in order to achieve a torque-fixed coupling between the drive shaft and the output-side shaft.

It can be provided that the elastic bearing completely surrounds a cylindrical motor housing of the drive motor in the circumferential direction.

Alternatively, the elastic bearing can surround the cylindrical motor housing of the drive motor in the circumferential direction partially, in particular in sections. Thus, the elastic bearing may have portions which are arranged in the circumferential direction of the cylindrical motor housing with intervals from one another. For example, four sections may be spaced apart at 90 ° intervals.

Furthermore, the output-side shaft may be mounted with a fixed bearing, which is supported on the housing.

According to one embodiment, the drive motor may be further held by at least one movable bearing, which allows an axial movement of the drive motor within a range of motion.

On a front side of the drive motor opposite the drive shaft, a first movable bearing can be arranged, which supports the housing elastically in the axial direction.

The drive motor may be biased by the first floating bearing in the axial direction.

It can be provided that the housing is provided with a housing stop, wherein the drive motor has a stop edge to hold the drive motor against rotation.

In particular, the housing stop and the stop edge can be designed to further ensure a limitation of the axial mobility in at least one axial direction.

Brief description of the drawings

Embodiments are explained below with reference to the accompanying drawings. Show it:

1 a plan view of an open hand-held machine tool with inserted drive motor;

2 a sectional view through the drive motor of the machine tool of 1 with its bearings; and

3 a perspective view of an exemplary form-locking cylinder.

Description of embodiments

A below with reference to the 1 and 2 described embodiment of the hand-held machine tool is a hammer drill. Overall, the present invention relates generally to machine tools in which a drive motor is provided for transmitting a torque.

The machine tool 1 has a housing 2 on, which consists of two half-shells 21 can be constructed. The half-shells 21 For example, injection molded parts may be made of a hard plastic, metal or the like. 1 shows a machine tool 1 with the housing open 2 ie with only one half shell 21 ,

In the case 2 is a drive motor 3 taken, which is used to drive a drive shaft 4 is trained. The drive shaft 4 is to driving a pinion 5 provided, which serves for coupling with a transmission, not shown, such. B. for coupling with a percussion of trained as a hammer drill machine tool 1 ,

The pinion 5 sits on a pinion shaft 6 in a camp 7 is stored. The camp 7 absorbs radial and axial forces and centers the pinion shaft 6 , The camp 7 thus serves to decouple shocks and bumps, by the impact mechanism in the direction of the drive motor 3 may occur. The camp 7 For example, it may be formed as a ball bearing, wherein an outer bearing ring 71 in the case 2 the machine tool 1 taken up and an inner bearing ring 72 firmly, in particular by press-fitting, with the pinion shaft 6 connected is. On the pinion shaft 6 can be between the drive motor 3 and the pinion 5 a fan 11 be arranged.

The drive motor 3 has a cylindrical motor housing 31 on, by a circumferential elastic bearing 8th , in particular in the form of an elastic O-ring is held. The outer peripheral surface 81 the elastic bearing 8th lies on an inner surface of the housing 2 at. Furthermore, the elastic bearing is located 8th with an inner surface 82 on the cylindrical motor housing 31 at. As a result, a bearing is formed, which is the drive motor 3 holds in the radial direction. Is the friction between the elastic bearing 8th and the motor housing 31 sufficiently high, so is due to the elasticity of the rotating bearing 8th In addition, a floating mounting of the drive motor 3 ensured in the axial direction.

As is clearer from the cross-sectional view of 2 shows, is the drive shaft 4 with the pinion shaft 6 via a radial bearing 9 coupled. The radial bearing 9 includes a positive locking cylinder 91 , the firm, z. B. by a press fit, with the drive shaft 4 of the drive motor 3 connected is. The positive locking cylinder 91 protrudes into a recess 61 the pinion shaft 6 into and is included in this. The positive locking cylinder 91 is in the recess 61 slidably provided in the axial direction.

In addition, the positive locking cylinder 91 in a first section 92 a non-circular cross section, the cross section of the inner recess 61 equivalent. To the first section 91 closes in the axial direction, a second section 93 on, the axial sliding of the positive locking cylinder 91 in the inner recess 61 allows. The non-round cross section of the positive locking cylinder 91 or the corresponding recess 61 may for example be hexagonal or have another shape. Thus, torques between the positive locking cylinder 91 and the pinion shaft 6 be transmitted, but no axial forces. Due to the radial bearing of the radial bearing 9 between the inner recess 61 and the positive locking cylinder 91 This is the position of the drive motor 3 from the position of the fixed camp 7 or the adjoining transmission decoupled. Due to the axial decoupling between the fixed position of the pinion shaft 6 and the position of the drive motor 3 Drive motors can also be installed with considerable component tolerances.

To limit the axial play of the drive motor 3 can continue a first floating bearing 10 on one of the drive shaft 4 opposite end face of the drive motor 3 be provided. The first floating bearing 10 can be on a jetty 11 inside the case 2 be arranged. The floating bearing 10 is preferably made of an elastic material, such. As a foam, plastic or the like, or formed as a spring. The first floating bearing 10 may be cup-shaped and for receiving a cylindrical coaxial first projection 32 of the drive motor 3 serve, the z. B. may be provided for receiving a motor-internal bearing for supporting a (not shown) motor shaft.

The first floating bearing 10 can during assembly of the drive motor 3 be biased and an axial force on the drive motor 3 in the direction of the pinion shaft 6 exercise. If this force is overpressed, a stop edge 33 of the drive motor 3 on a housing stop 12 abut to limit a movement of the drive motor 3 in the axial direction away from the pinion shaft 6 to enable. At the same time the housing stop 12 also serve one on the drive motor 3 to absorb acting torque, so that the drive motor 3 against rotations in the housing 2 is fixed.

Furthermore, a second floating bearing 13 be provided, that at the first floating bearing 10 opposite end face of the drive motor 3 is arranged. The second floating bearing 13 may be at a coaxial second cylindrical projection 35 be appropriate to surround this annular and z. B. be formed as a plastic ring. The second cylindrical projection 35 of the drive motor 3 can z. B. for receiving a further motor-internal bearing for supporting the (not shown) motor shaft. The further floating bearing 13 serves as one of the first floating bearing 10 opposite axial stop, so that a travel limit of the drive motor 3 in both axial directions through the first and second floating bearings 10 . 13 is guaranteed.

By the above-described embodiment with the radial bearing 9 , the elastic bearing 8th and the camp 7 Can handle large structural tolerances of the drive motor 3 be compensated. Because the pinion 5 for coupling with the gear (striking mechanism) not axially fixed to the drive motor 3 is connected, is an axial relative movement, in particular of the drive motor 3 between the components. This will be the drive motor 3 of the gearing, which is relatively accurately executed, axially decoupled with respect to a constructional tolerance.

The elastic bearing 8th compensates for the tolerances between the motor housing 31 and the inclusion in the housing half shell 21 , A slight misalignment of the drive motor 3 Can be compensated during operation by dynamic circumferential forces, causing the drive motor 3 is aligned in a stable state of equilibrium.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008063510 A1 [0002]

Claims (11)

Hand-operated machine tool ( 1 ) for driving a tool, comprising: - a housing ( 2 ); - one in the housing ( 2 ) received rotary drive motor ( 3 ); - one on the drive motor ( 3 ) arranged elastic bearing ( 8th ) to the drive motor ( 3 ) on the housing ( 2 ) in a radial direction; and - a radial bearing ( 9 ), which is designed to be a drive shaft ( 4 ) of the drive motor ( 3 ) and a driven-side shaft torque-tight to couple and decouple axially. Machine tool ( 1 ) according to claim 1, wherein the radial bearing ( 9 ) a form-locking cylinder ( 91 ), which in a recess ( 61 ) of the output-side shaft is received axially slidably. Machine tool ( 1 ) according to claim 2, wherein the positive locking cylinder ( 91 ) of the radial bearing ( 9 ) has a non-round cross-section, wherein the recess ( 61 ) of the output-side shaft has a corresponding cross-section in order to provide a torque-fixed coupling between the drive shaft ( 4 ) and the output side shaft. Machine tool ( 1 ) according to one of claims 1 to 3, wherein the elastic bearing ( 8th ) a cylindrical motor housing ( 31 ) of the drive motor ( 3 ) completely surrounds in the circumferential direction. Machine tool ( 1 ) according to one of claims 1 to 3, wherein the elastic bearing ( 8th ) a cylindrical motor housing ( 31 ) of the drive motor ( 3 ) in the circumferential direction partially, in particular in sections, surrounds. Machine tool ( 1 ) according to one of claims 1 to 5, wherein the driven-side shaft further comprises a fixed bearing ( 7 ) is mounted on the housing ( 2 ) is supported. Machine tool ( 1 ) according to one of claims 1 to 6, wherein the drive motor ( 3 ) by at least one floating bearing ( 10 . 13 ) holding an axial movement of the drive motor ( 3 ) within a range of motion. Machine tool ( 1 ) according to one of claims 1 to 7, wherein on one of the drive shaft ( 4 ) opposite end face of the drive motor ( 3 ) a first floating bearing ( 10 ) is arranged, which the housing ( 2 ) is elastically supported in the axial direction. Machine tool ( 1 ) according to claim 8, wherein the drive motor ( 3 ) by the first floating bearing ( 10 ) is biased in the axial direction. Machine tool ( 1 ) according to one of claims 8 and 9, wherein the housing ( 2 ) with a housing stop ( 12 ), wherein the drive motor ( 3 ) a stop edge ( 33 ) to the drive motor ( 3 ) against turning. Machine tool ( 1 ) according to claim 10, wherein the housing stop ( 12 ) and the stop edge ( 33 ) are formed to further ensure a limitation of the axial mobility in at least one axial direction.

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