Patent Document

This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2010/065511, filed on Oct. 15, 2010, which claims the benefit of priority to Serial No. DE 10 2009 054 640.5, filed on Dec. 15, 2009 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     DE 34 05 922 discloses a portable power tool, in particular a rotary hammer, having a transmission, a machine housing and an inner housing arranged inside the machine housing, wherein the inner housing is provided to receive transmission elements of the transmission. In this case, the transmission elements are mounted in the inner housing by means of bearing elements. The inner housing supports the transmission elements in an axial direction and in a radial direction. 
     SUMMARY 
     The disclosure relates to a portable power tool, in particular a rotary and/or demolition hammer, having a transmission, having a machine housing and having an inner housing arranged inside the machine housing, said inner housing being provided to at least partially receive at least one transmission element of the transmission. 
     It is proposed that the at least one transmission element is mounted in a manner distributed between the inner housing and the machine housing. The term “transmission” is intended to be understood here in particular as a mechanism which comprises at least two components, in particular transmission elements, which are provided, by means of interaction, to change at least the amount of a force, of a torque and/or of a rotational speed and/or with the aid of which a form of movement, such as a rotation, can be converted into a different form of movement, such as a translational movement, and/or which are provided to transmit percussive pulses. The components, in particular transmission elements, can in this case be in the form of gearwheels, shafts, strikers, percussive pins, hammer tubes, swash bearings, bearings and other components that appear to be practical to a person skilled in the art. Advantageously, the at least one transmission element is in the form of a hammer tube and/or of a shaft, in particular in the form of an output shaft and/or intermediate shaft. In this context, “provided” is intended to be understood as meaning in particular especially equipped and/or especially designed. 
     The term “machine housing” should be understood here in particular as defining an outermost cover which encloses the components of the portable power tool so that the components of the portable power tool are protected substantially against external influences, the cover being provided to allow a user of the portable power tool to grip and operate, in particular guide, the portable power tool. In this case, the machine housing can be formed from a unit which comprises at least two housing half-shells which can be joined together along a connecting plane. Particularly preferably, the machine housing is formed from a number of units, in particular from a transmission housing and a motor housing, wherein the transmission housing and the motor housing are formed in a pot-like manner. In order to form the machine housing, the pot-like transmission housing and the pot-like motor housing are connected together in a connecting plane by means of connecting elements which are known to a person skilled in the art. However, it is also conceivable for the transmission housing and the motor housing to have in each case two housing half-shells, which can be joined together in each case along a connecting plane. The machine housing can be formed from various materials that appear to be practical to a person skilled in the art, such as, for example, a metal, a nonferrous metal, etc., preferably a plastics material. The term “inside” is intended to be understood here in particular as defining a spatial position of at least the inner housing in relation to the machine housing, wherein the inner housing is enclosed substantially by the machine housing, in particular in a common plane which extends substantially perpendicularly to a rotational axis of a transmission element arranged inside the inner housing and/or to a rotational axis of a tool mount of the portable power tool. The expression “partially receive” is intended to be understood here in particular as an arrangement of the at least one transmission element in the inner housing, wherein at least subregions of the at least one transmission element are received in the inner housing, in particular are surrounded in a substantially form-fitting manner, so that at least one degree of freedom of movement of the at least one transmission element can be at least partially restricted. In connection with mounting of the at least one transmission element, “distributed” is intended to be understood in particular as meaning uncoupling of the inner housing from the machine housing with regard to a bearing function, in particular a radial bearing function, of the at least one transmission element. Thus, at least one bearing force of the at least one transmission element is supported via the inner housing and at least one bearing force of the at least one transmission element is supported via the machine housing in a manner uncoupled from the inner housing. 
     By means of the configuration according to the disclosure of the portable power tool, it is possible to counteract a summation of tolerances of a mounting of transmission elements in a particularly advantageous manner. As a result, play of the transmission elements, which is dependent on the tolerances, can particularly advantageously be kept low. In particular in the case of transmission elements which are driven in rotation, such as in particular an output shaft and/or an intermediate shaft, a high running accuracy, in particular a high true-running accuracy, can advantageously be achieved by way of the configuration according to the disclosure. In this way, the development of vibration can advantageously be counteracted. 
     Advantageously, the inner housing is provided to at least axially support the at least one transmission element. The designation “axially support” is intended to be understood here in particular as an arrangement at least of the inner housing in relation to the at least one transmission element, wherein the at least one transmission element bears directly or indirectly at least partially against the inner housing so that a flux of force can take place between the at least one transmission element and the inner housing, in particular a flux of force which runs in a substantially parallel manner to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of a tool mount of the portable power tool. Furthermore, by means of the axial support, at least one degree of freedom of movement of the at least one transmission element in at least one direction, in particular substantially parallel to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool, is intended to be restricted. The expression “substantially parallel” is intended to be understood here in particular as defining a direction which deviates from a reference direction by in particular less than 8°, advantageously less than 5° and particularly advantageously less than 2°. The inner housing can be formed with a small wall thickness, as a result of which material and costs can particularly advantageously be saved. 
     It is furthermore proposed that the machine housing is provided to at least radially support the at least one transmission element in a manner uncoupled from the inner housing. The designation “radially support” is intended to be understood here in particular as an arrangement of the machine housing in relation to the at least one transmission element, wherein the at least one transmission element bears directly or indirectly at least partially against the machine housing so that a flux of force between the at least one transmission element and the machine housing can take place, in particular a flux of force which runs in a substantially perpendicular manner to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool. As a result, radial bearing forces which proceed from the at least one transmission element can particularly advantageously be supported at the machine housing so that the running accuracy of the at least one transmission element can be positively influenced in a structurally simple manner. 
     Advantageously, the portable power tool has at least one supporting element which penetrates at least partially through the inner housing in a radial direction. In this context, a “supporting element” is intended to be understood in particular as a component which is provided to transmit forces and/or torques that occur in one component to another component. A “radial direction” is intended to be understood here in particular as a direction which runs in a substantially perpendicular manner to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool. In this context, “substantially perpendicular” is intended to be understood as a direction which encloses an angle, which has in particular a dimension of between 85° and 95°, with a reference direction. Particularly preferably, the at least one supporting element bears against the machine housing so that radial support, in particular radial support in a manner uncoupled from the inner housing, of the at least one transmission element on the machine housing can be achieved. By means of the configuration according to the disclosure, it is possible advantageously to uncouple the inner housing from a radial support of the at least one transmission element. 
     Preferably, the supporting element is configured in one piece with a supporting element which is provided to axially support the inner housing. In particular, the supporting element is formed in one piece with an intermediate flange which is provided to axially support the inner housing. The term “in one piece” is intended to be understood here in particular as formed in one part and/or from a casting and/or as a component which is only separable with the aid of a separating and/or cutting tool. In a preferred configuration, the supporting element has a free end that is directed radially outward. It is conceivable to arrange a damping means in the radial direction between the free end of the supporting element and the machine housing, so that vibrations which proceed from the at least one transmission element can be damped in a particularly advantageous manner. See, e.g., the damping member  25  illustrated in  FIG. 3 . The damping means can be formed from various materials that appear to be practical to a person skilled in the art. Particularly preferably, the damping means is formed from an elastomer. As a result, an operator can advantageously be relieved of load when operating the portable power tool. Furthermore, by means of the configuration according to the disclosure of the portable power tool, installation space, costs and assembly outlay can advantageously be reduced. 
     In addition, it is proposed that the inner housing has at least one radial cutout which is provided to at least partially receive the supporting element. A “radial cutout” is intended to be understood here in particular as a continuous cutout in a lateral surface, it being possible to guide a component through said cutout perpendicularly to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool. By means of interaction between the radial cutout in the inner housing and the supporting element, it is possible to realize advantageous support in a structurally simple manner. 
     In a particularly preferred configuration, the portable power tool comprises an intermediate flange which has at least one supporting element which is provided to axially support at least the inner housing. As a result, axial support of the inner housing can be achieved in a structurally simple manner. Components for realizing the axial support of the inner housing can advantageously be saved. 
     Preferably, the portable power tool according to the disclosure comprises at least two bearing planes in which the at least one transmission element is supported radially on the machine housing in a manner uncoupled from the inner housing. The bearing planes extend in this case in a substantially perpendicular manner to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool. Preferably, the at least two bearing planes are arranged in a manner spaced apart from one another in an axial direction which extends in a substantially parallel manner to the rotational axis of a transmission element arranged inside the inner housing and/or to the rotational axis of the tool mount of the portable power tool, specifically preferably with an axial spacing of at least 2 cm. Particularly preferably, in each case at least one radial bearing is arranged in the at least two bearing planes. As a result, a particularly advantageous flux of force can be achieved. 
     Furthermore, it is proposed that the inner housing is formed in a shell-like manner. The expression “shell-like” is intended to be understood here in particular as a structure in which the inner housing is formed from at least two housing half-shells which can be connected together along a connecting plane by means of connecting elements known to a person skilled in the art. Particularly preferably, the connecting plane of the housing half-shells of the inner housing extends through the rotational axis of a transmission element arranged inside the inner housing and/or through the rotational axis of the tool mount of the portable power tool. As a result, components, in particular transmission elements, arranged in the inner housing can advantageously be accessed for the purposes of maintenance and/or fitting and/or repair. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further advantages can be gathered from the following description of the drawing. The drawing illustrates an exemplary embodiment of the disclosure. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form practical further combinations. 
       In the drawing: 
         FIG. 1  shows a portable power tool according to the disclosure, 
         FIG. 2  shows the portable power tool according to the disclosure with the machine housing opened, 
         FIG. 3  shows a detail view of a mounted inner housing of the portable power tool according to the disclosure, 
         FIG. 4  shows a schematic sectional illustration of the machine housing along the line IV-IV in  FIG. 2  of the portable power tool according to the disclosure, and 
         FIG. 5  shows the portable power tool according to the disclosure with the inner housing opened. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a portable power tool  10  according to the disclosure, which is in the form of a rotary and/or demolition hammer. The portable power tool  10  comprises a transmission  12 , a machine housing  14  and an inner housing  16  ( FIG. 2 ) arranged inside the machine housing  14 , said inner housing being provided to receive a transmission element  18  of the transmission  12 . In this case, the transmission element  18  is mounted in a manner distributed between the inner housing  16  and the machine housing  14 . The transmission  12  comprises a percussion mechanism  36  for producing a percussive pulse. The transmission  12  is connected to a drive unit  36  (not shown in more detail here) that produces a drive torque. The percussive pulse of the percussion mechanism  36  and a rotation of an intermediate shaft of the percussion mechanism  36 , of a hammer tube of the percussion mechanism  36  and of a tool mount  40  of the portable power tool  10  are produced in a manner known to a person skilled in the art and so this is not described in more detail here. 
     The tool mount  40  of the portable power tool  10  is arranged in a front region  42  of the portable power tool  10  and is provided to receive a tool  44 . On a side  46  remote from the front region  42 , the portable power tool  10  comprises a main handle  48  for actuating the portable power tool  10  and to introduce a force initiated by an operator to the portable power tool  10 . The portable power tool  10  is also executed with a detachable auxiliary handle  50 . In this case, the auxiliary handle  50  can be fastened in a detachable manner to the portable power tool  10  via a latching connection or other connections that appear to be practical to a person skilled in the art. The auxiliary handle  50  is arranged on the portable power tool  10  in the vicinity of the tool mount  40  so that the portable power tool  10  can be guided by the operator. A main extension direction  52  of the portable power tool  10  extends from the main handle  48  in the direction of the tool mount  40 . In this case, the main extension direction  52  extends parallel to a rotational axis  54  of the tool  44  located in the tool mount  40  and to a rotational axis  54  of the transmission element  18  in the form of a hammer tube. Inside the transmission element  18  in the form of a hammer tube there are arranged a percussive pin, a striker and a hammer pin (not illustrated in more detail here) for transmitting the percussive pulse to the tool  44 . 
       FIG. 2  shows the portable power tool  10  according to the disclosure with the machine housing  14  opened. The machine housing  14  comprises a pot-like transmission housing  56  and a pot-like motor housing  58 . In the assembled state, the transmission housing  56  and the motor housing  58  are connected together in a connecting plane  60  such as to be separable in a manner known to a person skilled in the art. The connecting plane  60  extends perpendicularly to the rotational axis  54  of the tool  44  located in the tool mount  40  and to the rotational axis  54  of the transmission element  18  in the form of a hammer tube. The motor housing  58  is formed partially in one piece with the main handle  48 . Furthermore, the drive unit  38 , which is in the form of an electric motor, (not illustrated in more detail here) is arranged inside the motor housing  58 . The inner housing  16 , which is arranged inside the transmission housing  56  in the assembled state of the transmission housing  56 , is provided to axially support the transmission element  18  in the form of a hammer tube. 
     The transmission element  18  in the form of a hammer tube is mounted inside the inner housing  16  ( FIG. 5 ) by means of a bearing element  66  in the form of a bearing bush  64  and of a bearing element  70  in the form of a ball bearing  68 . The bearing bush  64  is arranged in this case in an intermediate flange  30  of the portable power tool  10 , said intermediate flange  30  being arranged partially inside the mounted inner housing  16 . Furthermore, the intermediate flange  30  has a supporting element  20 ,  24 , which is provided to axially support the inner housing  16 . The supporting element  20 ,  24  is formed in this case in one piece with the intermediate flange  30 . The inner housing  16  has a radial cutout  28 , which is provided to partially receive the supporting element  20 ,  24 . Furthermore, the inner housing  16  has grooves  72  for receiving the ball bearing  68  and the intermediate flange  30 , said grooves  72  extending in a circumferential direction  74  in the inner housing  16 . The circumferential direction  74  extends in a plane which extends perpendicularly to the rotational axis  54  of the tool  44  located in the tool mount  40  and to the rotational axis  54  of the transmission element  18  in the form of a hammer tube. As a result of interaction of peripheral regions  76  of the grooves  72 , the radial cutouts  28  in the inner housing  16  and the supporting element  20 ,  24 , the inner housing  16  is supported on the intermediate flange  30  in the axial direction  62 . The transmission element  18  in the form of a hammer tube is supported axially on the inner housing  16  via the ball bearing  68  arranged in one of the grooves  72  in the inner housing  16  and one of the peripheral regions  76  of the grooves  72 . 
     Furthermore, the portable power tool  10  has a supporting element  20 ,  24 , which penetrates partially through the inner housing  16  in a radial direction  22 . This supporting element  20 ,  24  is configured in one piece with the supporting element  20 ,  24  which is provided to axially support the inner housing  16 . In the assembled state of the machine housing  14  and the inner housing  16 , the supporting element  20 ,  24  extends, starting from the intermediate flange  30 , in the direction of the transmission housing  56  through the cutout  28  in the inner housing  16 . The supporting element  20 ,  24  has a free end  26  which is directed radially outward and bears against the transmission housing  56  in the assembled state of the portable power tool  10 . The transmission element  18  in the form of a hammer tube is supported radially on the machine housing  14 , in particular on the transmission housing  56 , in a manner uncoupled from the inner housing  16 . The intermediate flange  30  has a total of six supporting elements  20 ,  24 , which are formed partially in one piece with the intermediate flange  30 . The inner housing  16  has in this case six cutouts  28  for receiving the six supporting elements  20 ,  24 . The six supporting elements  20 ,  24  are in this case arranged at an equal spacing in the circumferential direction  74  on the intermediate flange  30 . Furthermore, the six cutouts  28  are likewise arranged at an equal spacing in the circumferential direction  74  on the inner housing  16 . However, it is also conceivable for more than six supporting elements  20 ,  24  or fewer than six supporting elements  20 ,  24  to be provided, depending on the requirements, and so a person skilled in the art will provide a number of supporting elements  20 ,  24  and cutouts  28  that is practical for a particular requirement. 
       FIG. 3  shows a detail view of the mounted inner housing  16  of the portable power tool  10  according to the disclosure, wherein the transmission housing  56  has been removed. On a side  78  of the inner housing  16  that faces the tool mount  40 , the ball bearing  68  for mounting the transmission element  18  in the form of a hammer tube is arranged in one of the grooves  72  in the assembled state of the inner housing  16 . On this side  78 , the inner housing  16  has a cutout  80 , which is provided to receive a radial element  82  of the transmission housing  56 . The inner housing has a total of six cutouts  80  for receiving a radial element  82 . The radial element  82  is in the form of a radial extension  84  of the transmission housing  56  ( FIG. 4 ). The radial extension  84  is arranged on an inner side  86  of the transmission housing  56 , said inner side  86  being directed toward the inner housing  16  in the assembled state of the transmission housing  56 . The transmission housing  56  has a total of six radial extensions  84 , which engage in each case in one of the six cutouts  80  in the inner housing  16  in the assembled state of the transmission housing  56 . However, it is also conceivable for more than six radial extensions  84  or fewer than six radial extensions  84  to be provided, depending on the requirements, and so a person skilled in the art will provide a number of radial extensions  84  and cutouts  80  that is practical for a particular requirement. The ball bearing  68  arranged in the inner housing  16  comprises an outer race  88  which bears against the radial extensions  84  in the assembled state of the transmission housing  56 . It is conceivable for damping means  87  to be arranged between the radial extensions  84  of the transmission housing  56  and the outer race  88  of the ball bearing  68 , said damping means  87  being provided to damp vibrations. By means of interaction between the outer race  88  of the ball bearing  68  and the radial extensions  84  of the transmission housing  56 , the transmission element  18  in the form of a hammer tube is supported radially on the transmission housing  56 . As a result, radial forces, which proceed from the transmission element  18  in the form of a hammer tube, are transmitted into the transmission housing  56 . The radial extensions  84  of the transmission housing  56  are inserted in the axial direction  62  into the cutouts  80  in the already mounted inner housing  16  when the transmission housing  56  is mounted. 
     Furthermore, the inner housing  16  has a bearing extension  90  which extends in a radial direction  22 . In the assembled state of the transmission housing  56 , the bearing extension  90  extends from the inner housing  16  in the direction of the transmission housing  56 . The bearing extension  90  is provided to receive a bearing element  94  in the form of a ball bearing  92 . To this end, the bearing extension  90  has a groove  96 , which extends in the circumferential direction  74  in the bearing extension  90  of the inner housing  16 . The ball bearing  92  is provided to mount a shaft  100 , in the form of an intermediate shaft  98 , of the transmission  12 . The intermediate shaft  98  is supported axially in this case by means of interaction between the ball bearing  92  and peripheral regions  102  of the groove  96  in the inner housing  16 . In order to radially support the intermediate shaft  98 , the bearing extension  90  has a cutout  104 , which is provided to receive a supporting element  106  of the transmission housing  56 . The bearing extension  90  has a total of three cutouts  104  ( FIG. 4 ) and the transmission housing  56  comprises three supporting elements  106 , wherein in each case one cutout  104  receives one supporting element  106 . The supporting elements  106  of the transmission housing  56  are provided to radially support the intermediate shaft  98  via the ball bearing  92 . The supporting elements  106  of the transmission housing  56  are inserted in the axial direction  62  into the cutouts  104  in the bearing extension  90  of the already mounted inner housing  16  when the transmission housing  56  is mounted. 
     The portable power tool  10  comprises two bearing planes  32 ,  34 , a first bearing plane  32  and a second bearing plane  34 , in which the transmission element  18  in the form of a hammer tube is supported radially on the machine housing  14  in a manner uncoupled from the inner housing  16 . The two bearing planes  32 ,  34  extend in this case perpendicularly to the rotational axis  54  of the tool  44  located in the tool mount  40  and to the rotational axis  54  of the transmission element  18  in the form of a hammer tube. The supporting elements  20 ,  24 , a subregion of the intermediate flange  30 , the bearing bush  64  and a subregion of the transmission element  18  in the form of a hammer tube are arranged in the first bearing plane  32  in the assembled state of the machine housing  14  and the inner housing  16 . The radial extensions  84  of the transmission housing  56 , the ball bearing  68  and a subregion of the transmission element  18  in the form of a hammer tube are arranged in the second bearing plane  34  in the assembled state of the machine housing  14  and the inner housing  16 . 
       FIG. 4  shows a schematic sectional illustration of the machine housing  14 , in particular the transmission housing  56 , of the portable power tool  10  according to the disclosure. The radial extensions  84  of the transmission housing  56  are arranged in a plane  108  ( FIG. 2 ), which extends perpendicularly to the rotational axis  54  of the tool  44  located in the tool mount  40  and to the rotational axis  54  of the transmission element  18  in the form of a hammer tube in the assembled state of the transmission housing  56 . Furthermore, the radial extensions  84  are arranged at an equal spacing in the circumferential direction  74  in the plane  108 . The plane  108  forms the second bearing plane  34  of the portable power tool  10  in the assembled state of the transmission housing  56 . 
     The supporting elements  106  of the transmission housing  56  are arranged in a plane  110  which extends parallel to the plane  108  ( FIG. 2 ), in which the radial extensions  84  of the transmission housing  56  are arranged. In this case, the plane  110 , in which the supporting elements  106  are arranged, is arranged in the axial direction  62  in the direction of the main handle  48  in a manner spaced apart from the plane  108 , which has the radial extensions  84  of the transmission housing  56 . The plane  110  forms a third bearing plane  112  of the portable power tool  10  in the assembled state of the transmission housing  56 . The third bearing plane  112  comprises a subregion of the bearing extension  90  of the inner housing  16 , the supporting elements  106 , the ball bearing  92  of the intermediate shaft  98  and a subregion of the intermediate shaft  98  in the assembled state of the portable power tool  10 . 
       FIG. 5  shows the portable power tool  10  according to the disclosure with the inner housing  16  opened and the transmission housing  56  removed. The inner housing  16  is formed in a shell-like manner. In this case, the inner housing  16  comprises two inner housing half-shells  114 ,  116 , which are connected together in a separable manner in a connecting plane. The connecting plane extends through the rotational axis  54  of the tool  44  located in the tool mount  40  and through the rotational axis  54  of the transmission element  18  in the form of a hammer tube.

Technology Category: 7