Patent Publication Number: US-9415497-B2

Title: Hand-held power tool

Description:
FIELD OF THE INVENTION 
     The present invention relates to a hand-held power tool. 
     BACKGROUND INFORMATION 
     Certain hand-held power tools, in particular an impact drill driver, having a gearbox assemblage, a hammer impact mechanism, and a tool spindle, are conventional. 
     SUMMARY 
     Example embodiments of the invention provide a hand-held power tool, in particular an impact drill driver, having a gearbox assemblage, a hammer impact mechanism, and a tool spindle. 
     It is provided that the gearbox assemblage have at least one gear stage element which is provided in order to split a power flow so as to make available different rotation speeds for an impact mode and a rotation mode. A “gearbox assemblage” is to be understood in particular as an assemblage that has at least one gear stage. The gear stage is advantageously arranged as a right-angle gearbox, as a bevel gear gearbox, and/or as another gear stage. The gear stage is arranged particularly advantageously as a planet wheel gear stage. A “hammer impact mechanism” is to be understood in particular as an impact mechanism having at least one linearly moved striker. Advantageously, the hammer impact mechanism moves the striker resiliently and/or pneumatically and/or hydraulically by a gate apparatus, by a wobble bearing, and/or advantageously by an eccentric element. The hammer impact mechanism is thus arranged preferably as a slide impact mechanism, as a wobble bearing impact mechanism, and/or as an eccentric impact mechanism. A “gate impact mechanism” is to be understood in particular as a hammer impact mechanism having a gate apparatus. A gate apparatus generates a linear motion between at least two regions by elements that are movable on a mechanically delimited endless track. A “wobble bearing impact mechanism” is to be understood in particular as a bearing having a finger, which is connected to a drive rotation element of the hammer impact mechanism and whose bearing plane deviates from a plane that is oriented perpendicular to the rotation axis of the drive rotation element. An “eccentric impact mechanism” is to be understood in particular as a hammer impact mechanism which is provided in order to generate, from a rotary motion, a linear motion perpendicular to the rotation axis of the rotary motion. The eccentric impact mechanism preferably has an eccentric element that is connected nonrotatably to the drive rotation element. A “hammer impact mechanism” is in particular to be understood as a ratchet impact mechanism in which a ratchet disk rotatable in an axial direction is uninterruptedly connected fixedly to the hand-held tool housing, and in which in order to generate a pulse, the ratchet disk coacts with a ratchet disk uninterruptedly mechanically connected to the tool spindle. A “ratchet impact mechanism” is, in particular, an impact mechanism in which an impact-generating ratchet disk is rotationally drivable, in which context an axial tooth set of the ratchet disk causes an axial motion of the tool spindle. A “tool spindle” is to be understood in particular as a shaft of the hand-held power tool that, in at least one operating state, transfers a rotary motion to a tool mounting apparatus of the hand-held power tool. A rotation axis of the tool spindle is preferably located on a rotation axis of an inserted tool and/or of the tool mounting apparatus. Particularly advantageously, in at least one operating state the tool spindle transfers a rotary motion and an impact motion to the tool mounting apparatus. Particularly advantageously, at least a part of the tool spindle is connected directly to the tool mounting apparatus. The tool spindle preferably has a mount for the tool mounting apparatus. Alternatively, the tool spindle can be arranged at least partly integrally with the tool mounting apparatus. The tool mounting apparatus is advantageously arranged as a tool chuck, as a hex receptacle, as an SDS receptacle (Special Direct System of Robert Bosch GmbH), and/or as another tool mounting apparatus. “Provided” is to be understood in particular to mean specially equipped and/or designed. A “gear stage element” is to be understood in particular as a sun gear, a ring gear, a planet wheel, another element of the gearbox assemblage, and/or in particular as a planet carrier. “Split” is to be understood in this connection, in particular, to mean that forces that cause torques act on the gear stage element at at least three points such as, in particular, at least one input point and at least two output points. 
     As a result of the configuration of the hand-held power tool, a rotation speed for an impact drive can be optimized to a particularly effective number of impacts, and particularly rapid drilling progress in an impact drilling mode can thus be achieved with small external dimensions of the hand-held power tool. 
     It is further provided that the gearbox assemblage generate, in at least one operating state, at least two output rotary motions that have a non-integer ratio to one another. In at least one operating state, the gearbox assemblage preferably transfers one of the output rotary motions to the tool spindle and one of the output rotary motions to the hammer impact mechanism. A “non-integer ratio” is to be understood in particular as a ratio that lies outside a set of natural numbers. The ratio is preferably outside the set of natural numbers between 2 and 6. An “output rotary motion” is to be understood in particular as a rotary motion that directs a power output out of the gearbox assemblage. As a result of the non-integer ratio between the two output rotary motions, an advantageous impact pattern can be achieved which enables a particularly effective impact drilling mode. 
     In example embodiments, it is provided that the gearbox assemblage have at least one ring gear that is supported axially movably. “Supported axially movably” is to be understood as, in particular, movably in a direction parallel to a rotation axis of the ring gear. Advantageously, the ring gear is movable with respect to a hand-held power tool housing, with respect to at least one planet wheel of an identical gear stage, and/or with respect to at least one planet wheel of a further gear stage. Particularly advantageously, the ring gear is movable so that it is coupled simultaneously and/or successively with at least one respective planet wheel of two different gear stages. As a result of the axially movably supported ring gear, an overload clutch and/or an impact shutoff system can be implemented with a simple design, economically, and in a manner that saves installation space. 
     It is furthermore provided that the hand-held power tool have a spring element that, in at least one operating state, exerts a force on the axially movable ring gear, with the result that the ring gear is moved, advantageously automatically, in at least one direction and a configuration of simple design is thus possible. 
     It is further provided that the gearbox assemblage have at least one gear stage which is provided in order to increase a rotation speed for an impact drive, with the result that an advantageously high number of impacts, and thus an effective impact drilling procedure, can be achieved. 
     In example embodiments, it is provided that the hammer impact mechanism have a resilient lever element, supported pivotably around a pivot axis, which is provided in order to drive a striker of the hammer impact mechanism in at least one operating state. A “lever element” is to be understood in particular as a movable element on which at least two torques act at a distance, advantageously at a different distance, from the pivot axis. The lever element is preferably pivotable around a pivot axis that is oriented perpendicular to the rotation axis of the tool spindle. Particularly advantageously, the lever element is configured rotationally asymmetrically and/or movably less than 360° around a rotation axis. The term “resilient” is to be understood in particular to mean that at least one point of the lever element is deflected at least 1 mm relative to another point of the lever element during an operating state. Advantageously, the lever element is made at least partly of spring steel. The term “drive” is to be understood in particular in accelerating fashion. As a result of the lever element, an effective and economical hammer impact mechanism can be implemented with a simple design. 
     In example embodiments, it is provided that in at least one operating state, the striker be freely movable in a principal working direction. The striker is preferably movable by the lever element. “Freely movable” is to be understood in this connection to mean in particular that the striker is decoupled from components, except for a sliding and/or rolling friction in a guide, over at least one travel segment in the principal working direction. A “principal working direction” is to be understood in particular as an impact pulse direction of the hammer impact mechanism. As a result of the striker that is freely movable in at least one operating state, particularly high impact energy along with convenient and, in particular, low-vibration operation can be achieved. 
     It is further provided that the tool spindle have a rotary entrainment contour which is provided for creating an axially displaceable and nonrotatable connection along a rotation axis. The rotary entrainment contour transfers advantageously principally, particularly advantageously exclusively, rotational forces. The rotary entrainment contour is arranged as a rotary entrainment contour, such as in particular a spline shaft profile and/or advantageously such as a tooth set. Particularly advantageously, the tool spindle is arranged in two parts and the rotary entrainment contour connects the two parts of the tool spindle to one another. As a result of the rotary entrainment contour, advantageously, a ratio between the striker mass and spindle mass can be optimally selected and the tool spindle can be axially decoupled from the gearbox assemblage so that wear, in particular on a planet carrier of the gearbox assemblage, can be minimized. 
     It is further provided that the gearbox assemblage have at least one sun gear that, in at least one operating state, is connected nonrotatably, in particular directly (i.e. without further interposed components) nonrotatably to at least a part of the hammer impact mechanism, thereby making possible a particularly simple design that saves installation space. Advantageously, the sun gear is connected nonrotatably to a drive rotation element of the hammer impact mechanism. 
     Also provided are an electric motor and a battery connector unit which is provided for supplying the electric motor with energy. For this purpose, the battery connector unit is preferably connected, in a ready-to-operate operating state, to a battery unit. A “battery connector unit” is to be understood in particular as a unit which is provided in order to create a contact with the battery unit. Advantageously, the battery connector unit creates an electrical and a mechanical contact. A “battery unit” is to be understood in particular as an apparatus having at least one storage battery, which apparatus is provided in order to supply the hand-held power tool with energy independently of a power grid. A particularly convenient hand-held power tool that is usable independently of a power network can thereby be implemented. Alternatively, the hand-held power tool is also operable with a different motor such as, in particular, an electric motor having a power connector, or a compressed-air motor. 
     It is furthermore provided that the gearbox assemblage have a gear stage that is arranged as a planet wheel gear stage. The planet wheel gear stage has at least one sun gear, a ring gear, at least one planet wheel, and/or a planet carrier. As a result of the planet wheel gear stage, an advantageous reduction ratio can be achieved in particularly space-saving fashion. 
     It is moreover provided that the hammer impact mechanism have a releasable, in particular mechanically releasable clutch apparatus which is provided in order to transfer a rotary motion. Preferably the clutch apparatus nonrotatably connects an impact mechanism shaft of the hammer impact mechanism and at least a part of the gearbox assemblage in at least one operating state. A “releasable clutch apparatus” is to be understood in particular as a clutch apparatus that in at least one operating state transfers a rotary motion, and in at least one operating state interrupts a transfer of the rotary motion. “Transferring a rotary motion” is to be understood as conveying in particular a rotation speed and/or a torque. As a result of the releasable clutch apparatus, the hammer impact mechanism can advantageously be disengaged, thus resulting in a hand-held power tool that is advantageously usable as a screwdriver. 
     It is further provided that the clutch apparatus be provided in order to be closed by a force transferred via the tool spindle. The clutch apparatus is preferably provided in order to be closed by a force acting in an axial direction of the tool spindle. As a result of the clutch apparatus closable via the tool spindle, the hammer impact mechanism can, advantageously, automatically be engaged in the context of a drilling procedure and disengaged at idle, making possible low wear and convenient operation. 
     In example embodiments, it is provided that the hand-held power tool have a torque setting unit having a clutch apparatus, which is provided for limiting, in at least one operating state, a maximum torque transferred via the tool spindle. The clutch apparatus is advantageously releasable. The “maximum torque” is preferably a torque that the tool spindle can transfer to an inserted tool during operation, in particular before a clutch apparatus automatically opens. The clutch apparatus is preferably arranged as an apparatus having spring-mounted or spring-loaded latching elements such as, in particular, balls. Other apparatuses are, however, also possible in principle. The latching elements can be loaded with a spring force in an axial and/or preferably in a radial direction. Undesirably high torques can be prevented by a limitation of the maximum torque. 
     It is further provided that the hand-held power tool have an operating element by which the clutch apparatus can be actuated. Advantageously, at least the operator can actuate the clutch apparatus by the operating element and/or by the tool spindle. Alternatively and/or additionally, a sensor unit and an actuation unit can actuate the clutch apparatus at least partly automatically on the basis of material properties of a workpiece. The clutch apparatus of the torque setting unit and the clutch apparatus of the hammer impact mechanism preferably have one operating element each and/or one common operating element. “Actuation” is to be understood in particular as opening and/or closing of the clutch apparatus, with the result that the impact mode can be conveniently engaged and disengaged by the operator and, in particular, the clutch apparatus of the torque setting unit can be uninterruptedly closed in a drilling mode. 
     It is further provided that the hammer impact mechanism have a drive rotation element having a rotation axis that is disposed coaxially with at least a part of the tool spindle. A “drive rotation element” is to be understood in particular as an element that executes a rotary motion in at least one operating state, and that moves at least one further element of the hammer impact mechanism. Advantageously, the drive rotation element is arranged as a shaft, particularly advantageously as a hollow shaft. The term “coaxially” is to be understood in particular to mean that in at least one operating state, at least a part of the tool spindle and the drive rotation element are driven rotationally around a common rotation axis. Preferably, at least a part of the tool spindle and the drive rotation element are rotatable relative to one another around the same rotation axis. Particularly advantageously, the hand-held power tool is arranged without countershafts. “Without countershafts” is to be understood in particular to mean that all the shafts of the hand-held power tool that, at least in a drilling mode, transfer a rotary motion, have a common rotation axis that advantageously coincides with the rotation axis of the tool spindle. “At least a part of the tool spindle” is to be understood in particular as a region of the tool spindle that is connected directly to the tool mounting apparatus. Alternatively and/or additionally, “at least a part of the tool spindle” is to be understood as a region of the tool spindle that is connected directly to the gearbox assemblage. As a result of the fact that the drive rotation element is disposed coaxially with at least a part of the tool spindle, a particularly compact and, in particular, short configuration can be achieved. The hand-held power tool achieves in this context a particularly high level of individual impact energy, which advantageously results in particularly good drilling progress. 
     In example embodiments, it is provided that the drive rotation element be arranged as an impact mechanism shaft that encases at least a region of the tool spindle. An “impact mechanism shaft” is to be understood in particular as a shaft that transfers a rotary motion to at least one further element of the hammer impact mechanism in order to generate an impact. Particularly advantageously, the tool spindle and the impact mechanism shaft rotate, in at least one operating state, at a different angular speed. The term “encase” is to be understood in particular to mean that the impact mechanism shaft surrounds the tool spindle to a very large extent, advantageously over 360°, in at least one plane. Advantageously, this plane is oriented perpendicular to the rotation axis of the drive rotation element. As a result of a corresponding configuration, a particularly space-saving design can be achieved, and the impact mechanism shaft encasing the tool spindle can be implemented with a low tool spindle mass and a small tool spindle diameter. 
     It is further provided that the hammer impact mechanism have an eccentric element, with the result that a capable and mechanically low-wear hand-held power tool can be made available with a simple design. 
     It is moreover provided that the eccentric element have a rotation axis that coincides with a rotation axis of the tool spindle. The term “coincide” is to be understood in particular to mean that the eccentric element is supported rotationally drivably around a rotation axis identical to that of the tool spindle. Preferably, the eccentric element and at least a part of the tool spindle are connected nonrotatably to one another. As a result, it is advantageously possible to dispense with a countershaft, and a particularly handy and lightweight hand-held power tool can be achieved. In particular, a capable hand-held power tool having a weight (including a battery unit) of less than 5 kg, advantageously less than 2 kg, particularly advantageously less than 1.5 kg can be achieved. 
     In example embodiments, it is provided that the hammer impact mechanism have a striker that at least partly surrounds the tool spindle in at least one plane. In this context, the tool spindle advantageously penetrates at least partly through the striker in the direction of the rotation axis of the tool spindle. Particularly advantageously, the tool spindle penetrates entirely through the striker. The striker preferably surrounds the tool spindle over 360° in at least one plane. The phrase “surrounds over 360° in at least one plane” is to be understood in particular to mean that the striker radially encases at least one point of the tool spindle in at least one plane. As a result of the fact that the striker at least partly surrounds the tool spindle, advantageously a tool spindle having a low mass can be achieved, and a particularly lightweight and compact hand-held power tool with a high level of capability can thus be made available. 
     In example embodiments, it is provided that in at least one operating state, the striker impact the tool spindle. Advantageously, the striker thereby transfers an impact pulse onto at least a part of the tool spindle, the tool spindle advantageously transferring the impact pulse onto a tool mounting apparatus of the hand-held power tool. The tool mounting apparatus preferably transfers the impact pulse onto an inserted tool. Alternatively and/or additionally, the striker impacts an impact transfer apparatus such as a setting head, or directly impacts an inserted tool of the hand-held power tool. The impact transfer apparatus transfers an impact motion directly onto an inserted tool. For this, the impact transfer apparatus is, for example, disposed at least partly coaxially inside the tool spindle. As a result of the fact that the striker impacts the tool spindle directly, the tool spindle can advantageously transfer an impact motion and a rotary motion in combined fashion onto a tool mounting apparatus, with the result that, advantageously, an economical, universally usable tool mounting apparatus of simple design can be used, and installation space can in turn be reduced. 
     Further advantages are set forth in the description below of the drawings. Two exemplifying embodiments are depicted in the drawings. The drawings and the specification contain numerous features in combination. One skilled in the art will appropriately consider the features individually as well, and group them into further combinations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a hand-held power tool according to an example embodiment of the present invention having a schematically depicted drivetrain, 
         FIG. 2  is a functional sketch of the drivetrain of  FIG. 1  having an electric motor, a gearbox assemblage, and a hammer impact mechanism, 
         FIG. 3  is a schematic partial section through the hammer impact mechanism of the hand-held power tool of  FIG. 1 , 
         FIG. 4  is a section through the hammer impact mechanism of  FIG. 3 , 
         FIG. 5  is a perspective depiction of a lever element of the hammer impact mechanism of  FIG. 3 , and 
         FIG. 6  is a functional sketch of an alternative exemplifying embodiment of the drivetrain of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a partly schematic depiction of a hand-held power tool  10   a  that is arranged as a cordless impact drill driver. Hand-held power tool  10   a  has a torque setting unit  12   a , a gearbox assemblage  14   a , a hammer impact mechanism  16   a , a tool spindle  18   a , a battery connector unit  20   a , a pistol-shaped hand-held power tool housing  22   a , and an electric motor  24   a  disposed in hand-held power tool housing  22   a . In a front region  28   a  of hand-held power tool  10   a , viewed oppositely to a principal working direction  26   a  of hand-held power tool  10   a , hand-held power tool  10   a  has a tool mounting apparatus  30   a  that is arranged as a tool chuck. Mounted in tool mounting apparatus  30   a  is an inserted tool  32   a  that, during operation of hand-held power tool  10   a , rotates around a rotation axis  34   a  of tool spindle  18   a  that extends parallel to principal working direction  26   a . Rotation axis  34   a  is arranged as a principal rotation axis, i.e. multiple elements of hand-held power tool  10   a  are rotatable about said rotation axis  34   a.    
     An operating element  36   a  of torque setting unit  12   a  is disposed annularly around rotation axis  34   a  of tool spindle  18   a , between hand-held power tool housing  22   a  and tool mounting apparatus  30   a . Disposed on an upper side  38   a , i.e. a side facing away from battery connector unit  20   a , of hand-held power tool  10   a  is an operating element  40   a  that enables an operator (not further depicted) to change over between a drilling or screwing mode and a hammer drilling mode. 
     Electric motor  24   a  is disposed in a rear region  42   a , i.e. a region facing away from tool mounting apparatus  30   a , of hand-held power tool housing  22   a . A stator (not further depicted) of electric motor  24   a  is connected nonrotatably to hand-held power tool housing  22   a . Gearbox assemblage  14   a  is disposed in a tubular upper region  44   a , disposed axially with respect to rotation axis  34   a , of the pistol-shaped hand-held power tool housing  22   a . A lower region  46   a  of hand-held power tool housing  22   a , which adjoins upper region  44   a  approximately at right angles, forms a handle  48   a . Battery connector unit  20   a  is disposed at a lower end of lower region  46   a . In a ready-to-operate state (as shown), a battery unit  50   a  is connected to battery connector unit  20   a . During operation, battery unit  50   a  supplies electric motor  24   a  with energy. 
     As  FIGS. 2 and 3  show, hammer impact mechanism  16   a  has a drive rotation element  52   a  having a rotation axis  34   a  that is disposed coaxially with respect to tool spindle  18   a . Drive rotation, element  52   a  is arranged as an impact mechanism shaft  54   a . Impact mechanism shaft  54   a  encases a region of tool spindle  18   a  that faces toward gearbox assemblage  14   a . Rotation axis  34   a  of impact mechanism shaft  54   a  is oriented parallel to principal working direction  26   a  of hand-held power tool  10   a . Tool spindle  18   a  connects tool mounting apparatus  30   a  to gearbox assemblage  14   a  along rotation axis  34   a  nonrotatably, and is arranged for the most part as a solid shaft. 
     Hammer impact mechanism  16   a  is embodied as an eccentric impact mechanism that has an eccentric element  56   a . As shown by the section (A-A) depicted in  FIG. 4 , eccentric element  56   a  has a rotation axis that coincides with rotation axis  34   a  of tool spindle  18   a . Eccentric element  56   a  is constituted by a sleeve whose wall thickness  58   a  continuously increases and then decreases over a 360-degree circuit around rotation axis  34   a . Eccentric element  56   a  is connected nonrotatably to impact mechanism shaft  54   a , and is penetrated by the latter in an axial direction. Hammer impact mechanism  16   a  has an eccentric outer element  60   a  that is moved by eccentric element  56   a  during a hammer drilling mode. Eccentric outer element  60   a  is arranged as an approximately elliptical disk. It has a round orifice  62   a  that is disposed in a region  64   a , facing away from handle  48   a , of eccentric outer element  60   a . Eccentric element  56   a  is supported in orifice  62   a , movably relative to eccentric outer element  60   a , by way of a bearing (not further depicted). Eccentric outer element  60   a  further has an aperture  80   a  that is disposed in a region, facing toward handle  48   a , of eccentric outer element  60   a . Aperture  80   a  is penetrated by a resilient lever element  66   a . Lever element  66   a  prevents a rotation of eccentric outer element  60   a  in a circumferential direction relative to hand-held power tool housing  22   a.    
     Hammer impact mechanism  16   a  has a striker  68   a . Lever element  66   a  drives striker  68   a  during a hammer drilling mode. Lever element  66   a  is arranged as a bracket, L-shaped in a side view, made of spring steel. As  FIG. 5  shows, lever element  66   a  has a horseshoe-shaped region  70   a  that is penetrated by tool spindle  18   a . Hammer impact mechanism  16   a  has a housing-mounted pivot shaft  72   a  around which lever element  66   a  is tiltable. Housing-mounted pivot shaft  72   a  is oriented perpendicular to rotation axis  34   a  of tool spindle  18   a.    
       FIGS. 2 and 3  further show that striker  68   a  of hammer impact mechanism  16   a  is freely movable in principal working direction  26   a  during a free-flight phase. The free-flight phase is a time period that begins with the end of an acceleration of striker  68   a  by lever element  66   a , and ends immediately before an impact. Upon impact, striker  68   a  transfers an impact pulse to tool spindle  18   a . For this, striker  68   a  impacts a transfer element  74   a  of tool spindle  18   a . Transfer element  74   a  is arranged as a thickening of tool spindle  18   a  that has a surface  76   a , on the side facing toward striker  68   a . Surface  76   a  is oriented parallel to an impact surface  78   a  of striker  68   a . Striker  68   a  surrounds tool spindle  18   a  over 360° in planes that are oriented perpendicular to rotation axis  34   a  of tool spindle  18   a . Striker  68   a  is guided on tool spindle  18   a  and is supported rotatably, with respect to hand-held power tool housing  22   a , around rotation axis  34   a  of tool spindle  18   a . Alternatively, the striker can also be guided at its outer contour and/or can be rotationally secured with respect to the hand-held power tool housing. 
     Upon a rotation of eccentric element  56   a , eccentric outer element  60   a  moves perpendicular to rotation axis  34   a  of tool spindle  18   a . As a result of a motion of eccentric outer element  60   a , an end  82   a , disposed tiltably in aperture  80   a  of eccentric outer element  60   a , of lever element  66   a  is moved, and lever element  66   a  is thereby tilted. Lever element  66   a  thereby accelerates striker  68   a  out of an initial position, facing toward gearbox assemblage  14   a , in the direction of principal working direction  26   a , by the fact that a driving end  84   a  of lever element  66   a  presses against a first bracing surface  86   a  of striker  68   a . After acceleration, striker  68   a  moves in principal working direction  26   a  into the free-flight phase, in which driving end  84   a  of lever element  66   a  is disposed in a free region  88   a  of striker  68   a  and is thus decoupled from striker  68   a  in principal working direction  26   a . At the end of this free-flight phase, striker  68   a  encounters transfer element  74   a  of tool spindle  18   a  and transfers its momentum to tool spindle  18   a . Lever element  66   a  then moves striker  68   a  back into the initial position by the fact that driving end  84   a  of lever element  66   a  exerts a force on a second bracing surface  90   a  of striker  68   a , said surface being disposed, with reference to first bracing surface  86   a , on a different side of free region  88   a . As a result of the resilient configuration of lever element  66   a , smooth profiles are achieved for the forces that act between lever element  66   a  and striker  68   a.    
     Gearbox assemblage  14   a  has four gear stages, which are embodied as planet wheel gear stages  92   a ,  94   a ,  96   a ,  98   a . The four planet wheel gear stages  92   a ,  94   a ,  96   a ,  98   a  are disposed behind one another along rotation axis  34   a  of tool spindle  18   a . The four planet wheel stages  92   a ,  94   a ,  96   a ,  98   a  each have a ring gear  100   a ,  102   a ,  104   a ,  106   a , a sun gear  108   a ,  110   a ,  112   a ,  114   a , a planet carrier  116   a ,  118   a ,  120   a ,  122   a , and four planet wheels  124   a ,  126   a ,  128   a ,  130   a , only two of which are depicted in each case. Planet wheels  124   a  of first planet wheel gear stage  92   a  mesh with sun gear  108   a  of first planet wheel gear stage  92   a  and with ring gear  100   a  of first planet wheel gear stage  92   a , and are supported rotatably on planet carrier  116   a  of first planet wheel gear stage  92   a . Planet carrier  116   a  of first planet wheel gear stage  92   a  guides planet wheels  124   a  of first planet wheel gear stage  92   a  on a circular path around rotation axis  34   a  of tool spindle  18   a . Second planet wheel gear stage  94   a , third planet wheel gear stage  96   a , and fourth planet wheel gear stage  98   a  are constructed correspondingly thereto. 
     Sun gear  108   a  of first planet wheel gear stage  92   a  is connected nonrotatably to electric motor  24   a  and is disposed next to electric motor  24   a  in principal working direction  26   a , between tool mounting apparatus  30   a  and electric motor  24   a . Ring gear  100   a  of first planet wheel gear stage  92   a  is connected nonrotatably to hand-held power tool housing  22   a . Planet carrier  116   a  of first planet wheel gear stage  92   a  is connected nonrotatably to sun gear  110   a  of second planet wheel gear stage  94   a , ring gear  102   a  of which is likewise connected to hand-held power tool housing  22   a . Planet carrier  118   a  of second planet wheel gear stage  94   a  is connected nonrotatably to sun gear  112   a  of third planet wheel gear stage  96   a . Ring gear  104   a  of third planet wheel gear stage  96   a  is likewise connected nonrotatably to hand-held power tool housing  22   a  during a drilling, screwdriving, or hammer drilling procedure. The first, the second, and the third planet wheel gear stage  92   a ,  94   a ,  96   a  thus each bring about a gear reduction in the direction of tool mounting apparatus  30   a . A gear reduction thus likewise occurs between sun gear  108   a  of first planet wheel gear stage  92   a  and planet carrier  120   a  of third planet wheel gear stage  96   a . A ratio of this gear reduction between a rotation speed of electric motor  24   a  and a rotation speed of tool spindle  18   a  is equal to approximately 60:1. 
     In addition, one skilled in the art is familiar with possibilities for switching to an alternative conversion ratio between a rotation speed of electric motor  24   a  and a rotation speed of tool spindle  18   a . For example, ring gear  102   a  of second planet wheel gear stage  94   a  can be nonrotatably connectable, alternatively to hand-held power tool housing  22   a , to planet carrier  116   a  of first planet wheel gear stage  92   a  by way of a clutch apparatus (not further depicted). The alternative conversion ratio between the rotation speed of a motor speed and the rotation speed of tool spindle  18   a  is equal to approximately 15:1. 
     Gearbox assemblage  14   a  has a gear stage element  132   a  that splits a power flow. Gear stage element  132   a  is embodied as a common planet carrier  120   a ,  122   a  of the third and the fourth planet wheel gear stage  96   a ,  98   a . Tool spindle  18   a  has a rotary entrainment contour  134   a  that creates, along rotation axis  34   a , an axially displaceable and nonrotatable connection to gearbox assemblage  14   a , more precisely to gear stage element  132   a . A pickoff of rotation speed of tool spindle  18   a  accordingly occurs at planet wheel  120   a  of third planet wheel gear stage  96   a.    
     In this example, rotary entrainment contour  134   a  is arranged as an internal tooth set  136   a  of gear stage element  132   a  and an external tooth set  138   a  of tool spindle  18   a . Alternatively, pickoff could occur at the ring gear of third planet wheel gear stage  96   a.    
     Alternatively or in addition to rotary entrainment contour  134   a  shown in  FIG. 2  and previously described, a rotary entrainment contour  140   a  can, as shown in  FIG. 3 , divide tool spindle  18   a  axially into two parts  142   a ,  144   a . The one part  142   a  of tool spindle  18   a  is connected directly to gearbox assemblage  14   a . The other part  144   a  of tool spindle  18   a  is connected directly to tool mounting apparatus  30   a . The previously described rotary entrainment contour  134   a  can be omitted. Part  142   a  of tool spindle  18   a  that is connected directly to gearbox assemblage  14   a  can then be connected fixedly in an axial direction to gear stage element  132   a . As a result, a mass of the axially movable part  144   a  of tool spindle  18   a  can be reduced. 
     Sun gear  114   a  of fourth planet wheel gear stage  98   a  is connected, during a hammer drilling mode, nonrotatably to drive rotation element  52   a . Sun gear  114   a  of fourth planet wheel gear stage  98   a  is thus, in the context of a hammer drilling procedure, connected nonrotatably to eccentric element  56   a  of hammer impact mechanism  16   a . Alternatively, ring gear  106   a  of fourth planet wheel gear stage  98   a  could also be connected nonrotatably to drive rotation element  52   a.    
     Ring gear  106   a  of fourth planet wheel gear stage  98   a  is supported axially movably. Gearbox assemblage  14   a  has a coupling element  146   a  that connects ring gear  106   a  of fourth planet wheel gear stage  98   a  nonrotatably and axially displaceably to hand-held power tool housing  22   a . As a result of this disposition, gearbox assemblage  14   a —more precisely fourth planet wheel gear stage  98   a —generates from the two power flows of the common planet carrier  120   a ,  122   a  of the third and the fourth planet wheel gear stage  96   a ,  98   a , during a hammer drilling mode, output rotary motions that have a non-integer ratio to one another. In addition, fourth planet wheel gear stage  98   a  increases a rotation speed for an impact drive, i.e. a rotation speed of impact mechanism shaft  54   a  or of drive rotation element  52   a  is higher than a rotation speed of tool spindle  18   a . Gearbox assemblage  14   a —more precisely gear stage element  132   a —thus makes available different rotation speeds for an impact drive and a rotary drive. 
     Hand-held power tool  10   a  has a first releasable clutch apparatus  148   a  that transfers a rotary motion during a hammer drilling mode. First clutch apparatus  148   a  is arranged as a claw clutch, and remains closed in the context of an axial motion of tool spindle  18   a  caused by an impact. In a hammer drilling mode, first clutch apparatus  148   a  connects hammer impact mechanism  16   a  to sun gear  114   a  of fourth planet wheel gear stage  98   a.    
     First clutch apparatus  148   a  furthermore has a spring element  150   a  that is arranged as a spiral spring. Spring element  150   a  opens first clutch apparatus  148   a  when tool spindle  18   a  is unloaded oppositely to principal working direction  26   a . In this case hammer impact mechanism  16   a  is deactivated. First clutch apparatus  148   a  is closed during a hammer drill mode by a force transferred via tool spindle  18   a  in an axial direction and proceeding from inserted tool  32   a . When tool spindle  18   a  is loaded with a force, as a result of a force generated by the operator onto a workpiece (not further depicted) via an inserted tool  32   a  mounted in tool mounting apparatus  30   a , spring element  150   a  is compressed and first clutch apparatus  148   a  is closed. The force is applied in an axial direction in the context of a hammer drilling mode, via a shaped element  152   a  that is connected to tool spindle  18   a , onto impact mechanism shaft  54   a  and thus onto first clutch apparatus  148   a.    
     In addition, hand-held power tool  10   a  has operating element  40   a  with which the operator can actuate first clutch apparatus  148   a  by uninterruptedly opening first clutch apparatus  148   a . Hammer impact mechanism  16   a  is thus deactivated in this operating state. This operating element  40   a  thus enables a manual changeover between a drilling or screwdriving mode and a hammer drilling mode, and drilling and screwdriving can be performed with hand-held power tool  10   a  without an impact pulse. Operating element  40   a  is embodied as a slide switch. 
     Torque setting unit  12   a  has a clutch apparatus  154   a  that limits a transferable torque. A maximum torque is settable by torque setting unit  12   a . This further, second clutch apparatus  154   a  is disposed between ring gear  104   a  of third planet wheel gear stage  96   a  and ring gear  106   a  of fourth planet wheel gear stage  98   a . Second clutch apparatus  154   a  opens automatically at a settable maximum torque that acts on tool spindle  18   a . When second clutch apparatus  154   a  is open, ring gear  104   a  of third planet wheel gear stage  96   a  is axially secured and rotationally movable. Second clutch apparatus  154   a  is arranged as an overload clutch, known to one skilled in the art, the response torque of which is modifiable by an axial force on second clutch apparatus  154   a . For example, second clutch apparatus  154   a  is arranged as a shaped-element clutch having oblique surfaces, or as a friction clutch. Alternatively, ring gear  106   a  of fourth planet wheel gear stage  98   a  serves as a shaped element, by the fact that it meshes simultaneously with planet wheels  128   a ,  130   a  of third planet wheel gear stage  96   a  and of fourth planet wheel gear stage  98   a  and, when the maximum torque is exceeded, becomes displaced in principal working direction  26   a  and releases planet wheels  128   a  of third planet wheel gear stage  96   a . For this purpose, ring gear  106   a  of fourth planet wheel gear stage  98   a  is preferably arranged to be wider than planet wheels  128   a ,  130   a  of the third and/or the fourth planet wheel gear stage  96   a ,  98   a.    
     Hand-held power tool  10   a  has a spring element  156   a  that, during a working procedure, exerts a force on the axially movable ring gear  106   a  of fourth planet wheel gear stage  98   a  and thus on second clutch apparatus  154   a , and thus closes second clutch apparatus  154   a . By operating element  36   a  of torque setting unit  12   a , second clutch apparatus  154   a  can be shifted by the operator, i.e. a force on the axially movable ring gear  106   a  can be set. This is done by an axial motion of a contact point  158   a  of spring element  156   a . When the maximum torque of tool spindle  18   a  is exceeded and clutch apparatus  154   a  is not uninterruptedly closed manually, second clutch apparatus  154   a  produces a counterforce and compresses spring element  156   a , and clutch apparatus  154   a  opens. Operating element  36   a  of torque setting unit  12   a  is arranged as a ring rotatable by the operator. 
     Operating element  36   a  further has a shaped element (not further depicted) which is provided in order to manually close second clutch apparatus  154   a  uninterruptedly. This is done by a corresponding setting, by the operator, of operating element  36   a . Opening of second clutch apparatus  154   a  in the context of a drilling mode can thereby be prevented at all torques that are transferred via tool spindle  18   a  and do not exceed a safety torque. 
     Gearbox assemblage  14   a  has two bearing elements  160   a ,  162   a  that radially support tool spindle  18   a . First bearing element  160   a  is disposed on the side of tool spindle  18   a  facing toward tool mounting apparatus  30   a . First bearing element  160   a  is connected axially fixedly to tool spindle  18   a , and is supported axially displaceably in hand-held power tool housing  22   a . Alternatively, the first bearing element can also be connected axially fixedly to the hand-held power tool housing, and supported axially displaceably on the tool spindle. Disposed on the side of tool spindle  18   a  facing away from tool mounting apparatus  30   a  is second bearing element  162   a , which supports tool spindle  18   a  inside sun gear  114   a  of fourth planet wheel gear stage  98   a . Alternatively, tool spindle  18   a  can be supported by the common planet carrier  120   a ,  122   a  of the third and the fourth planet wheel gear stage  96   a ,  98   a.    
       FIG. 6  shows a further exemplifying embodiment. To differentiate the exemplifying embodiments, the letter “a” in the reference characters of the exemplifying embodiment in  FIGS. 1 to 5  is replaced by letters “b” in the reference characters of the exemplifying embodiment in  FIG. 6 . The description that follows is limited substantially to the differences with regard to the exemplifying embodiment in  FIGS. 1 to 5 ; reference may be made, with regard to components, features and functions that remain the same, to the description of the exemplifying embodiment in  FIGS. 1 to 5 . In particular, different dispositions and combinations of the above-described clutch apparatus are possible. 
       FIG. 6 , like  FIG. 2 , shows in particular a torque setting unit  12   b , a gearbox assemblage  14   b , a hammer impact mechanism  16   b , and a tool spindle  18   b.    
     Torque setting unit  12   b  has latching elements  164   b  that are arranged as balls. Latching elements  164   b  are supported in shaped elements (not further depicted) and are disposed between a ring gear  104   b  of a third planet wheel gear stage  96   b  and a hand-held power tool housing  22   b . Latching elements  164   b  are spring-loaded radially to a rotation axis  34   b  of tool spindle  18   b , by a spring element  156   b  of torque setting unit  12   b , with a force that is settable by the operator. If a torque transferred via tool spindle  18   b  exceeds a set maximum torque, latching elements  164   b  push the shaped elements apart against a force of spring element  156   b . Ring gear  104   b  of third planet wheel gear stage  96   b  thus rotates relative to hand-held power tool housing  22   b , and tool spindle  18   b  transfers no torque at that time. 
     Ring gear  104   b  of third planet wheel gear stage  96   b  and a ring gear  106   b  of a fourth planet wheel gear stage  98   b  are nonrotatably connected to one another by a clutch apparatus  148   b . When clutch apparatus  148   b  is opened, ring gear  106   b  of fourth planet wheel gear stage  98   b  is freely rotatable around rotation axis  34   b , and hammer impact mechanism  16   b  is thus disengaged for a drilling and screwdriving mode. 
     Clutch apparatus  148   b  is closed by two shaped elements  152   b ,  168   b . First shaped element  152   b  transfers a force in an axial direction from tool spindle  18   b  onto an impact mechanism shaft  54   b . This shaped element  152   b  is axially mechanically connected fixedly to tool spindle  18   b.    
     Second shaped element  166   b  is connected in an axial direction to impact mechanism shaft  54   b . Said element transfers force in an axial direction via a bearing  168   b  to ring gear  106   b  of fourth planet wheel gear stage  98   b . The force closes clutch apparatus  148   b  in the context of a drilling and screwdriving mode. Alternatively, a transfer of force via fourth planet wheel gear stage  98   b  is possible. Clutch apparatus  148   b  is opened by a spring element  150   b  that applies axial force, directed onto a tool mounting apparatus  30   b , onto impact mechanism shaft  54   b  via a bearing  170   b.