Abstract:
A hand-held power tool, particularly a hammer drill, includes a work spindle, a hand-held power tool housing and an intermediate shaft, which is arranged in parallel to the work spindle and mounted in an axially displaceable manner for changing the operational mode, and a tooth sleeve, which is provided to transfer a torque to the intermediate shaft. The tooth sleeve is fixed in the axial direction by means of the hand-held power tool housing.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2009/063524, filed Oct. 16, 2009, which claims the benefit of priority to Serial No. 10 2008 054 692.5, filed Dec. 16, 2008 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     The disclosure relates to a hand-held power tool as described herein. 
     A hand-held power tool, in particular a hammer drill, having a work spindle, a hand-held power tool housing and an intermediate shaft that is arranged parallelwise in relation to the work spindle and mounted in an axially displaceable manner for a change of operating mode, and having a toothed sleeve provided to transmit a torque to the intermediate shaft, has already been proposed in DE 38 19 125 A1. 
     SUMMARY 
     The disclosure relates to a hand-held power tool, in particular a hammer drill, having a work spindle, a hand-held power tool housing and an intermediate shaft that is arranged parallelwise in relation to the work spindle and mounted in an axially displaceable manner for a change of operating mode, and having a toothed sleeve provided to transmit a torque to the intermediate shaft. 
     It is proposed that the toothed sleeve is fixed in the axial direction by means of the hand-held power tool housing. By a “work spindle” is also to be understood, in particular, a hammer tube in which an element provided for generating an impulse is guided. The work spindle is rotatable and in this case can be realized so as to be axially fixed and/or at least partially axially movable and/or of multiple parts. By a “change of operating mode” is to be understood, in particular, a switchover between two operating modes, in particular between an impact drilling operation, a drilling operation and/or a chiseling operation. By an “operating mode” are to be understood, in particular, the chiseling operation, the impact drilling operation and/or the drilling operation. In the case of a chiseling operation, a tool executes a motion along a main working direction. In the case of a drilling operation, the tool executes a rotary motion about a rotation axis, parallelwise in relation to the main working direction. In the case of an impact drilling operation, the tool executes the two motions simultaneously. By a “main working direction” is to be understood, in particular, a direction in which the hand-held power tool is normally moved during a working process, for example directly during a drilling process. By “provided” is to be understood, in particular, specially equipped and/or designed. By a “toothed sleeve” is to be understood, in particular, an element that at least partially surrounds a cavity and/or has at least one toothed element that preferably consists of teeth and tooth spaces and is realized as a spur gear, for transmitting a torque. By the term “transmit a torque” is also to be understood, in particular, transmission of a power by means of a rotary motion. By “fixed in the axial direction” is to be understood, in particular, immovable along an axis. In particular, in the case of a change of operating mode, the toothed sleeve remains unmoved in the axial direction in relation to a hand-held power tool housing and/or in relation to a motor shaft. By a “hand-held power tool” is to be understood in this connection, in particular, in addition to a hammer drill, also an impact drill and/or another hand-held power tool considered appropriate by persons skilled in the art. Owing to the design of the hand-held power tool according to the disclosure, the toothed sleeve fixed in the axial direction enables wearing of the toothed sleeve and/or of the motor shaft to be minimized in an effective manner and, advantageously, enables skewing of the toothed sleeve and/or of the motor shaft and/or of the intermediate shaft upon switching under load to be prevented. 
     Further, the hand-held power tool has a motor shaft, which is arranged parallelwise in relation to the work spindle. Advantageously, the toothed sleeve is fixed in the axial direction relative to the motor shaft. By “arranged parallelwise” is to be understood in this connection, in particular, that rotation axes of the work spindle, of the motor shaft and of the intermediate shaft are aligned parallelwise in relation to one another. Alternatively, the hand-held power tool can have a motor shaft that is arranged perpendicularly in relation to the work spindle. The motor shaft arranged parallelwise in relation to the work spindle enables an advantageous small structural height to be achieved. 
     Furthermore proposed is a switching element, which is axially displaceable relative to the toothed sleeve for at least one change of operating mode, whereby, advantageously, in the case of at least two operating modes such as, for example, in the case of a drilling operation and an impact drilling operation, a reliable and rotationally fixed connection between the intermediate shaft and the switching element is possible. 
     Further, the hand-held power tool has a coupling element, which connects at least the switching element and the toothed sleeve to one another in a rotationally fixed manner. By a “coupling element” is to be understood, in particular, a device that connects two elements to one another in a rotationally fixed manner irrespective of an axial displacement of the elements towards one another or away from one another. 
     Particularly advantageously, the coupling element is realized as a splined-shaft profile. Other realizations that are considered appropriate by persons skilled in the art and that perform a like function are also possible. Through the coupling element, advantageously, the switching element and the toothed sleeve are connected to one another, in all positions of the switching element and of the intermediate shaft, by a rotationally fixed connection. 
     In addition, it is proposed that the toothed sleeve at least partially surrounds the switching element. By “at least partially surround” is to be understood, in particular, that the switching element is arranged at least partially in the cavity surrounded by the toothed sleeve, whereby, advantageously, a required structural space can be reduced. 
     In a further development, a spring element is proposed, which is provided to displace at least the switching element at least in the case of a change of operating mode, whereby a simple design is possible. In particular, the spring element displaces the switching element in the case of a change from the drilling operation to the impact drilling operation. Instead of a spring element realized as a helical spring, another device considered appropriate by persons skilled in the art such as, for example, a rubber element, a hydraulic, magnetic or pneumatic device, can also be used to displace the switching element. 
     Furthermore proposed is a spring element that at least partially surrounds the toothed sleeve, whereby a particularly small amount of structural space is required for a transmission arrangement. 
     Further, a connecting element is proposed, which connects the intermediate shaft and the switching element to one another in a rotationally fixed manner in at least one operating mode. By a “connecting element” is to be understood, in particular, a device that, in at least one operating mode, prevents a rotatory relative motion of two elements, in this case the intermediate shaft and the switching element, in relation to one another. In particular, the connecting element prevents a rotatory relative motion of the two elements in relation to one another in a drilling operation and in an impact drilling operation. In at least one other operating mode, in particular in a chiseling operation, the connecting element renders possible a free running, i.e. a rotatory relative motion in which the two elements can be turned against one another. The first connecting element enables an advantageous rotary motion of the tool to be achieved during at least one operating mode. 
     In addition it is proposed that the connecting element is opened in the case of a chiseling operation. Advantageously, the connecting element that connects the intermediate shaft and the switching element to one another in a rotationally fixed manner in at least one operating mode is opened in the case of a chiseling operation. By “opened” it is to be understood in this connection, in particular, that the two elements connected by the connecting element are connected to one another in a rotationally fixed manner in the case of a drilling operation and an impact drilling operation and now have a free running in relation to one another. Advantageously, the opened connecting element enables an application range of the hand-held power tool to be extended. 
     Furthermore, a second connecting element is proposed, which, in at least one operating mode, transmits at least a torque from the switching element to a stroke generator, whereby an advantageous impact motion of the tool can be achieved. The stroke generator in this case can be realized, for example, by means of a wobble drive and/or an eccentric drive. 
     In a further development, it is proposed that the second connecting element is opened in the case of a drilling operation, whereby, advantageously, an application range of the hand-held power tool can be extended. 
     Further, an additional bearing element is proposed, by means of which at least the toothed sleeve is seated. By “additional bearing element” is to be understood, in particular, a bearing element that can be produced separately from elements that adjoin when in an integrated state, such as, in particular, a housing element and/or the toothed sleeve. Advantageously, the additional bearing element is realized as a stud. By the term “seated by means of the bearing element” is to be understood in this connection, in particular, that the bearing element diverts and/or supports linear forces occurring at least in the case of a seating. In this case, a bearing renders possible differently oriented motions, in this case a differing axial rotary motion of the toothed sleeve and of the bearing element. Various bearings considered appropriate by persons skilled in the art may be used, such as plain bearings, rolling bearings, sheet-metal cups, needle bearings and/or deep-groove ball bearings. The additional bearing element enables the toothed sleeve to be seated in a structurally simple manner. 
     In addition, it is proposed that the additional bearing element is at least connected to a housing element in a rotationally fixed manner, whereby the hand-held power tool is easily assembled. 
     In a further development, a journal is proposed, which is realized so as to be integral with a housing element and by means of which at least the toothed sleeve is seated. By “integral” in this connection is to be understood, in particular, that the journal and the housing element are produced from a common blank. An advantageous saving in components is thereby achieved. 
     Furthermore, a bearing is proposed, which seats at least the toothed sleeve in a stroke generator. By the term “seats in a stroke generator” is to be understood, in particular, that forces occurring in the case of a seating are diverted and/or supported by means of at least one component of the stroke generator, preferably a transmission element of the stroke generator. In particular, the bearing element is to seat the toothed sleeve in the stroke generator to which the second connecting element transmits a torque. Particularly advantageously, the seating of the toothed sleeve in the stroke generator enables structural space to be saved. 
     Further, at least one bearing is proposed, which is arranged within the toothed sleeve and which axially and/or radially seats the toothed sleeve. By “within the toothed sleeve” is to be understood, in particular, that the toothed sleeve at least partially surrounds the bearing. Additional structural space can be saved as a result of the bearing being within the toothed sleeve. 
     In a further development, it is proposed that the toothed sleeve has a journal. Advantageously, the journal is connected to the toothed sleeve in a rotationally fixed manner. The journal of the toothed sleeve enables a bearing to be arranged advantageously within the hand-held power tool housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages are given by the following description of the drawings. Nine exemplary embodiments of the disclosure are represented in the drawings, three exemplary embodiments relating, in particular, to a device for transmitting a torque, and six exemplary embodiments relating to a seating of a toothed sleeve. The drawings, the description and the claims contain numerous features in combination. Expediently, persons skilled in the art will also consider the features individually and combine them into appropriate, further combinations. In particular, the exemplary embodiments one to three can be combined with the exemplary embodiments four to nine. 
       In the drawing: 
         FIG. 1  shows a schematic representation of a hand-held power tool realized as a hammer drill, 
         FIG. 2  shows a schematic inside view of the hand-held power tool from  FIG. 1  in a first exemplary embodiment, 
         FIG. 3  shows a schematic inside view of the hand-held power tool in a second exemplary embodiment, 
         FIG. 4  shows a schematic inside view of the hand-held power tool in a third exemplary embodiment, 
         FIG. 5  shows a schematic detail view of a transmission arrangement of the hand-held power tool of the first exemplary embodiment, 
         FIG. 6  shows a schematic detail view of the transmission arrangement in a fourth exemplary embodiment, 
         FIG. 7  shows a schematic detail view of the transmission arrangement in a fifth exemplary embodiment, 
         FIG. 8  shows a schematic detail view of the transmission arrangement in a sixth exemplary embodiment, 
         FIG. 9  shows a schematic detail view of the transmission arrangement in a seventh exemplary embodiment, and 
         FIG. 10  shows a schematic detail view of the transmission arrangement in an eighth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a schematic representation of a first exemplary embodiment of a hand-held power tool  10   a , realized as a hammer drill, having a pistol-shaped hand-held power tool housing  86   a . The hand-held power tool  10   a  has a main handle  46   a , which is angled in relation to a main working direction  44   a  and which is realized so as to be integral with the hand-held power tool housing  86   a . In a front region  48   a  of the hand-held power tool  10   a  there is an additional handle  50   a , a tool chuck  52   a , a tool  54   a  realized as an SDS-plus drilling chisel, and an operating element  56   a . An operator, not represented in greater detail, can effect a change of operating mode by means of the operating element  56   a.    
     Shown in  FIG. 2  is a schematic representation of an inside view of a transmission arrangement  57   a  of the hand-held power tool  10   a , which is provided to change the operating mode of the hand-held power tool  10   a . The hand-held power tool  10   a  has a motor shaft  14   a , which can be driven by a motor, not represented in greater detail, and a work spindle  12   a . A rotation axis  58   a  of the motor shaft  14   a  extends parallelwise in relation to the main working direction  44   a  and parallelwise in relation to a rotation axis  60   a  of the work spindle  12   a . An impulse-generating device, which is represented only partially and which has a stroke generator  32   a , is accommodated in the work spindle  12   a  and in front of and behind the work spindle  12   a  in the main working direction  44   a . Further, the hand-held power tool  10   a  has an intermediate shaft  16   a  arranged parallelwise in relation to the work spindle  12   a . The intermediate shaft  16   a  is disposed in an axially displaceable manner for a change of operating mode by means of the operating element  56   a , and has an outer toothing  62   a , which, in at least one operating mode, transmits a torque to the work spindle  12   a , which is realized as a hammer tube. Furthermore, the hand-held power tool  10   a  has a toothed sleeve  18   a , which transmits a torque from the motor shaft  14   a  to a switching element  22   a  during an operation. 
     The toothed sleeve  18   a  is fixed in an axial direction  20   a  relative to the motor shaft  14   a  by means of the hand-held power tool housing  86   a . For a change of operating mode, the hand-held power tool  10   a  has the switching element  22   a , which is axially displaceable relative to the toothed sleeve  18   a  for a change of operating mode. A transmission of the torque from the toothed sleeve  18   a  to the switching element  22   a  is effected by means of a coupling element  24   a , which is realized as a splined-shaft profile and which connects the switching element  22   a  and the toothed sleeve  18   a  to one another in a rotationally fixed manner. 
     In addition, the hand-held power tool  10   a  has the stroke generator  32   a , having a transmission element  64   a  and having an eccentric gear  66   a , and has a spring element  26   a . At an end lying in the main working direction  44   a , the motor shaft  14   a  has a toothing  68   a  that, together with the toothing  70   a  of the toothed sleeve  18   a , constitutes a spur gear transmission. The toothed sleeve  18   a  is realized as a hollow shaft, which has three outer radii that become smaller along the main working directions  44   a , and two inner radii that become smaller in a radial direction along the main working directions  44   a . The toothing  70   a  is arranged in the region of the largest outer radius, which is constituted by a ring pressed onto the toothed sleeve  18   a . A transition  72   a  between the middle and the small outer radius to a support serves, in the axial direction, as a bearing contact surface for the spring element  26   a . A transition  74   a  between the large and the small inner radius serves as a bearing contact surface for a bearing  76   a . The bearing  76   a  seats the toothed sleeve  18   a  in a housing element  36   a , which is indirectly connected to the hand-held power tool housing  86   a  via the bearing element  34   a . The toothed sleeve  18   a  surrounds the switching element  22   a  in a region  78   a , which lies in the main working direction  44   a  and extends in the form of a tube, parallelwise in relation to the main working direction  44   a.    
     In the case of a change of operating mode between drilling operation and impact drilling operation, the spring element  26   a  displaces the switching element  22   a , and is realized as a helical spring. For this purpose, the spring element  26   a  bears on the toothed sleeve  18   a  and on the switching element  22   a , and presses the two elements  18   a ,  22   a  apart from one another in an axial direction. Further, during the chiseling operation and the impact drilling operation, the spring element  26   a  presses the switching element  22   a  against the transmission element  64   a  of the stroke generator  32   a , and thereby enables a rotationally fixed connection between the switching element  22   a  and the transmission element  64   a . The spring element  26   a  surrounds the toothed sleeve  18   a  and the switching element  22   a , partially in each case, in a region that extends, in the form of a tube, parallelwise in relation to the main working direction  44   a.    
     The hand-held power tool  10   a  has a first connecting element  28   a , which, in the case of a drilling operation and an impact drilling operation, connects the intermediate shaft  16   a  and the switching element  22   a  to one another in a rotationally fixed manner. The first connecting element  28   a  is realized as a spline. In the case of a chiseling operation, the intermediate shaft  16   a  is displaced axially in the main working direction  44   a  by means of the operating element  56   a . As a result, the first connecting element  28   a  opens, in that the intermediate shaft  16   a  is moved away from the switching element  22   a , and no torque is transmitted to the intermediate shaft  16   a , and consequently to the work spindle  12   a  and the tool  54   a.    
     The hand-held power tool  10   a  has a second connecting element  30   a , which, in the case of a chiseling operation and an impact drilling operation, connects the switching element  22   a  and the transmission element  64   a  of the stroke generator  32   a  to one another in a rotationally fixed manner. The second connecting element  30   a  is realized as a spline, which is arranged on the switching element  22   a , on an outer radius in the main working direction  44   a . In the case of a drilling operation, the intermediate shaft  16   a  is displaced axially contrary to the main working direction  44   a , by means of the operating element  56   a . As a result, the intermediate shaft  16   a  likewise displaces the switching element  22   a  contrary to the main working direction  44   a , against a spring pressure of the spring element  26   a . As a result, the second connecting element  30   a  opens. No torque is transmitted to the transmission element  64   a  and, consequently, to the stroke generator  32   a.    
     Further exemplary embodiments of the disclosure are shown in  FIGS. 3 ,  4  and  6  to  10 . To distinguish the exemplary embodiments, the letter a in the references of the exemplary embodiment in  FIGS. 1 ,  2  and  5  is replaced by the letters b to h in the references of the exemplary embodiments in  FIGS. 3 ,  4  and  6  to  10 . The following descriptions are limited substantially to the differences between the exemplary embodiments, and reference may be made to the description of the other exemplary embodiments, in particular in  FIGS. 1 ,  2  and  5 , in respect of components, features and functions that remain the same. 
       FIG. 3  shows a hand-held power tool  10   b , in which, unlike the first exemplary embodiment in  FIG. 2 , a spring element  26   b  and a toothed sleeve  18   b  are arranged partially within a switching element  22   b . The switching element  22   b  in this case partially surrounds the toothed sleeve  18   b . In this case, the spring element  26   b  is arranged within the toothed sleeve  18   b  and the switching element  22   b . Webs  80   b  arranged within the toothed sleeve  18   b  and within the switching element  22   b  serve as bearing contact surfaces for the spring element  26   b.    
     Furthermore,  FIG. 4  shows a hand-held power tool  10   c , in which, unlike the first exemplary embodiment in  FIG. 2 , a first connecting element  82   c  connects a toothed sleeve  18   c  and an intermediate shaft  16   c  in a rotationally fixed manner in the case of a drilling operation or an impact drilling operation. The first connecting element  82   c  is realized as a splined-shaft profile and arranged within the toothed sleeve  18   c . In this case, a switching element  22   c  is arranged coaxially in relation to the intermediate shaft  16   c . The switching element  22   c  partially surrounds the toothed sleeve  18   c  in a region extending, in the form of a tube, parallelwise in relation to the main working direction  44   a . In the case of a drilling operation and an impact drilling operation, the intermediate shaft  16   c  engages in the splined-shaft profile of the toothed sleeve  18   c . In the case of a chiseling operation, the intermediate shaft  16   c  is displaced, and moves in a region  84   c  of the toothed sleeve  18   c  that has no splined shaft. In this case, no torque is transmitted from the toothed sleeve  18   c  to the intermediate shaft  16   c.    
       FIG. 5  shows a detail representation of the seating of the toothed sleeve  18   a  of the first exemplary embodiment from  FIG. 2 . For the purpose of seating the toothed sleeve  18   a , the transmission arrangement  57   a  has the additional bearing element  34   a , which is realized as a stud. The bearing element  34   a  is pressed into the housing element  36   a , which is realized as an intermediate flange, and is thereby connected to the hand-held power tool housing  86   a . Axially, the bearing element  34   a  is secured by means of a snap ring  88   a.    
     For the purpose of radially seating the toothed sleeve  18   a , the transmission arrangement  57   a  has a needle bearing  90   a , which is arranged coaxially in relation to the toothed sleeve  18   a , between the bearing element  34   a  and the toothed sleeve  18   a . Axially, the toothed sleeve  18   a  is seated by means of a washer  92   a  inserted in the toothed sleeve  18   a . The needle bearing  90   a  and the washer  92   a  can be realized in an integral manner. 
     Further,  FIG. 6  shows an alternative seating of a toothed sleeve  18   d . In this case, a journal  38   d  is provided instead of a stud as in  FIG. 5 . The journal  38   d  is made from light metal, realized so as to be integral with a housing element  36   d , and is thus connected to a hand-held power tool housing  86   d . An axial and radial seating is effected by means of an integral sheet-metal cup  94   d , which extends axially along the journal  38   d  and radially along the housing element  36   d . Alternatively, it is possible for the sheet-metal cup  94   d  to be realized in multiple parts, as a sleeve and as a washer. 
     In an exemplary embodiment shown in  FIG. 7 , a bearing element  34   e  realized as a stud is pressed into a toothed sleeve  18   e . For the purpose of radial seating, a transmission arrangement  57   e  has a needle bearing  90   e , which is arranged between the bearing element  34   e  and a housing element  36   e  that is realized as an intermediate flange and connected to a hand-held power tool housing  86   e.    
     Furthermore,  FIG. 8  shows an exemplary embodiment in which a journal  96   f  is formed onto a toothed sleeve  18   f . The journal  96   f  and the toothed sleeve  18   f  are thus realized in an integral manner. An axial and radial seating is effected by means of a sheet-metal cup  94   f , which extends axially along the journal  96   f  and radially along the housing element  36   f , which is connected to a hand-held power tool housing  86   f.    
     A further exemplary embodiment is shown by  FIG. 9 . In the case of the exemplary embodiment, a toothed sleeve  18   g  has, on a side that is contrary to the main working direction  44   g , an extension  98   g  that extends in the radial direction and that includes an offset portion  100   g  in the main working direction  44   g . The offset portion  100   g  has a toothing  68   g , which is meshed with a motor shaft  14   g . By means of a bearing  40   g  that is realized as a plain bearing, the toothed sleeve  18   g  is seated in a transmission element  64   g  of a stroke generator  32   g , which is realized as a wobble bearing. Axially, the toothed sleeve  18   g  is seated against a housing element  36   g , and thus against a hand-held power tool housing  86   g , by means of a washer  92   g.    
       FIG. 10  shows a bearing  42   h , which is arranged within a toothed sleeve  18   h  and pressed into the toothed sleeve  18   h , and which is realized as a deep-groove ball bearing. The bearing  42   h  is fixed axially with a retaining ring  102   h  on an additional bearing element  34   h  that is realized as a shoulder screw, and is thereby seated against a housing element  36   h  and a hand-held power tool housing  86   h.