Abstract:
The invention relates to a hand machine tool which has an intermediate flange, particularly for receiving transmission elements. The flange has at least one base body having at least one bearing point. It is proposed that at least one opening is provided at least in the area of the bearing point.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a 35 USC 371 application of PCT/EP2008/051508 filed on Feb. 7, 2008. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is based on a hand-held power tool with an intermediate flange, in particular for accommodating transmission elements. 
     2. Description of the Prior Art 
     DE 10 2004 036 585 A1 has disclosed a hand-held power tool with an intermediate flange for accommodating transmission elements, which has a plurality of base bodies with bearing positions. The intermediate flange serves to accommodate a drive piston, a motor shaft, and an intermediate shaft; the intermediate flange can have a grid-shaped construction for strength reasons. 
     SUMMARY OF THE INVENTION 
     The invention is based on a hand-held power tool with an intermediate flange, in particular for accommodating transmission elements, which has at least one base body with at least one bearing position. 
     According to one proposed embodiment, at least one opening is situated at least in the vicinity of the bearing position. The expression “at least in the vicinity of the bearing position” is understood in particular to mean that the opening can also extend further into the base body beyond the bearing position. This simplifies the assembly and disassembly of the transmission elements of the hand-held power tool. The intermediate flange is preferably embodied as part of a transmission unit of the hand-held power tool; it is provided, for example, to accommodate elements that can be moved or driven in rotatary and/or translatory fashion such as a motor shaft, a hammer tube, an intermediate shaft, a drive piston, etc. and/or to accommodate other parts in which these elements are contained or through which they are guided, e.g. a bearing, a hammer tube, etc. The intermediate flange can, however, also be embodied as part of another unit of the hand-held power tool such as a motor unit and/or can be embodied in the form of a fastening flange between two units of the hand-held power tool, e.g. between a motor unit and a transmission unit. The intermediate flange can additionally serve to absorb and dissipate forces coming from the transmission elements and/or motor elements and/or heat coming from the transmission elements and/or motor elements, which is particularly suitable for use in hand-held power tools with a housing manufactured out of plastic. In the present exemplary embodiment, the intermediate flange preferably serves to accommodate a hammer tube supported in the bearing position, an intermediate shaft, and a motor shaft. The intermediate shaft can be driven by the motor shaft via a transmission. A wobble bearing is slid onto the intermediate shaft and by means of a wobble pin, converts a rotary motion of the intermediate shaft into a reciprocating motion of a drive piston in the hammer tube. 
     The assembly or insertion of the wobble pin into the drive piston was previously carried out by inserting the wobble pin laterally into the drive piston through an opening in the base body and then rotating the intermediate shaft by 90°. According to the invention, at least one opening is situated at least in the vicinity of the bearing position. The opening advantageously extends further into the base body beyond the bearing position. In the present exemplary embodiment, the hammer tube is accommodated in this bearing position. Because of this embodiment, the drive piston can already be slid onto the wobble pin ahead of time and can be inserted together with the intermediate shaft equipped with the wobble pin into the opening extending in the base body and in the bearing position; the assembly direction corresponds to the direction of the base body longitudinal axis, i.e. the intermediate shaft assembly can preferably be installed axially. The elimination of the lateral insertion of the wobble pin and rotation of the intermediate shaft enables a particularly simple assembly and disassembly of the transmission elements. The assembly also requires less space since the transmission elements can be inserted axially into the opening extending in the base body and in the bearing position. 
     In another embodiment, the hand-held power tool has a bearing that is accommodated in the bearing position and can be open or likewise slit, at least in the vicinity of the opening of the bearing position. This advantageously permits the bearing to be inserted into the bearing position before assembly of the transmission elements. During assembly, it is then possible for the wobble pin to be inserted axially into the opening that extends in the base body, the bearing position, and the bearing. 
     The bearing is advantageously secured against rotating and/or sliding axially by means of at least one device in the bearing position, thus enabling the use of a simple, inexpensive slide bearing. 
     According to one proposed embodiment, the intermediate flange is embodied in the form of a separate component, thus making it possible to achieve a high degree of flexibility in the embodiment of the intermediate flange. 
     According to one proposed embodiment, the intermediate flange is at least partially integrated into a housing of the hand-held power tool, i.e. is at least partially embodied as a housing element. This achieves a reduced manufacturing complexity because the housing and the intermediate flange can be at least partially embodied of one piece with each other. 
     Another advantageous reduction in the manufacturing complexity can be achieved in that the intermediate flange and in particular, the first base body can be at least partially composed of two shells. This permits a simple insertion of the bearing for the hammer tube during assembly of the hand-held power tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be further described in detail below in conjunction with the drawings, in which: 
         FIG. 1  shows a rotary hammer with an intermediate flange that has a base body unit, 
         FIG. 2  shows the intermediate flange from  FIG. 1  in a perspective depiction with a base body of the base body unit, which has a bearing position according to the invention, and 
         FIG. 3  shows the intermediate flange from  FIGS. 1 and 2  in which an intermediate shaft assembly is installed. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a hand-held power tool embodied in the form of a rotary hammer  10 . It includes a motor unit  26  with a motor shaft  30  that can be driven by an electric motor  28 , an intermediate shaft assembly  32  with an intermediate shaft  34  that can be driven by the motor shaft  30  via a transmission  36 , and a wobble bearing  38 —preferably a ball bearing—that is mounted on the intermediate shaft  34  and uses a wobble pin  40  to convert a rotary motion of the intermediate shaft  34  into a reciprocating motion of a drive piston  42  in a hammer tube  44 . 
     The drawing also shows an intermediate flange  12 , which is particularly designed to accommodate transmission elements and in which the hammer tube  44 , the intermediate shaft  34 , and the motor shaft  30  are bearing-mounted and which supports bearing forces of the hammer tube  44 , the intermediate shaft  34 , and the motor shaft  30  in a housing  24  of the rotary hammer  10 , which housing is preferably manufactured out of plastic. 
     The intermediate flange  12  is shown in more detail in a perspective depiction in  FIG. 2 . It is composed of a base body unit  46 , which includes a first sleeve-shaped base body  14 , a second sleeve-shaped base body  48 , and a third essentially disk-shaped base body  50  with a sleeve-shaped extension  52  formed onto it; the two sleeve-shaped base bodies  14 ,  48  are attached to the third base body  50  at their first ends  54 ,  56 . 
     In the present exemplary embodiment, the intermediate flange  12  is embodied in one piece. It is also conceivable, however, for the above-explained elements  14 ,  48 ,  50 ,  52  to be separate components that are attached to one another for example by means of welding. Alternatively, however, it is also conceivable to use other attaching methods deemed suitable by those skilled in the art such as soldered connections, riveted connections, glue connections, etc. 
     The first base body  14  has a bearing position  18  at its second end  60  for accommodating the hammer tube  44 ; the bearing position  18  is preferably embodied of one piece with the base body  14 . Alternatively, the bearing position  18  can also be a separate component that is attached to the base body  14 . 
     In order to improve the assembly of the hand-held power tool, according to the invention, at least one slot-shaped opening  16  is situated at least in the region of the bearing position  18 . In the present exemplary embodiment, the opening  16  extends further into the base body  14  beyond the bearing position  18 , with the opening  16  advantageously ending in the vicinity of the first end  54  of the first base body  14 . Ideally, the opening  16  extends in the direction of a longitudinal axis  58  of the base body  14 ; the width  62  of the opening  16  in the circumference direction can change over the length  66  extending in the direction of the longitudinal axis  58 . As a result, the base body  14  has an opening  16  that extends essentially the entire length of the longitudinal axis  58  of the base body  14  and is open at the top, i.e. at a second end  60  of the base body  14 ; the length  66  of the opening  16  depends on the embodiment of the intermediate shaft assembly  32 . Furthermore, additional openings can be provided in the bearing position  18  and/or in the base body  14 . 
     The bearing position  18  serves to accommodate a bearing  20 , in particular a slide bearing, which can likewise be open or slit, at least in the vicinity of the opening  16  of the bearing position  18 ; here, too, it is also conceivable for the opening of the bearing  20  to be situated at other locations. Also in this case, the width  68  in the circumference direction of the opening in the bearing  20  does not have to correspond to the width  62  of the opening  16  in the base body  14  in the circumference direction; in the present exemplary embodiment, the widths  62  and  68  correspond to each other. In the present exemplary embodiment, a slide bearing  20  is provided, which is secured against rotating by means of at least one device, not visible here, in the bearing position  18 . The device for preventing rotation can, for example, be composed of pins; other devices deemed suitable by those skilled in the art can also conceivably be used. In addition, the bearing  20  is secured against sliding axially by means of at least one device  22  in the bearing position  18 . The device  22  for preventing axial sliding is composed, for example, of screws or tabs on the base body  14 , which are bent over after installation of the bearing  20 ; here, too, any other suitable embodiment can also conceivably be used. Preferably, a radial fixing can be achieved, e.g. by means of a caulking. 
     In the present exemplary embodiment, the intermediate flange  12  is embodied in the form of a separate component. To this end, the intermediate flange  12  can be situated inside the housing  24  of the hand-held power tool  10 ; for example, it rests in annular fashion against a housing shell. In order to achieve a high bearing capacity of the intermediate flange  12  and nevertheless be able to embody it in as inexpensive a fashion as possible, the intermediate flange  12  is preferably composed of aluminum. 
     Alternatively, however, the intermediate flange  12  can also be at least partially integrated into the housing  24  of the hand-held power tool  10  or can be embodied as an element of the housing. The intermediate flange  12  can be advantageously composed of at least two shells. 
     In order to assemble the transmission elements  30 ,  34 ,  44  according to  FIG. 3 , the drive piston  42  can already be slid onto the wobble pin  40  ahead of time and can be inserted together with the intermediate shaft assembly  32  into the opening  16  extending in the base body  14 , the bearing position  18 , and the bearing  20 ; the assembly direction corresponds to the direction of the base body longitudinal axis  58 . Then the intermediate shaft  34  is inserted into the second base body  48 . 
     The foregoing relates to the preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.