Abstract:
A device for the variable driving of a hollow shaft and an inner shaft or spindle that is supported on the latter and lies inside it, is particularly suited for moving component parts of a tire building machine, using driving devices. The hollow shaft is coupled to the inner shaft or spindle by way of a planetary gear mechanism or a harmonic-drive gear mechanism, which is respectively constructed as a differential-speed gear mechanism. The hollow shaft and the shaft or spindle are made to run synchronously by way of a single driving device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation, under 35 U.S.C. §120, of copending international application No. PCT/EP2007/061986, filed Nov. 7, 2007, which designated the United States; this application also claims the priority, under 35 U.S.C. §119, of German patent application DE 10 2006 061 463.1, filed Dec. 23, 2006; the prior applications are herewith incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a device for the variable driving of a hollow shaft and a shaft or spindle that is supported thereon and lies inside it, in particular for moving component parts of a tire building machine, by using drive devices. 
     In the case of machines for producing and for building pneumatic vehicle tires, it is customary to use a hollow shaft with an internal spindle supported thereon in order, for example, to be able to position cambering heads via a movement of the spindle, and in order to set the tire building machine into rotation via the hollow shaft, for example so as to roll up the belt package of a pneumatic vehicle tire. It must thereby also be ensured that the shaft can be operated without components being actuated by the spindle. Shaft and spindle must therefore also be capable of synchronous movement. 
     In the case of a prior art tire building machine, the shaft and the spindle are driven by one motor, or each by one motor, and can be mechanically coupled one on another during rotation of the shaft by way of a toothed coupling. However, it is thereby impossible to actuate the spindle and rotate the shaft simultaneously. In addition, only an incremental measurement system is available on two axes in the case of that prior art device. When changing between the operating modes of “rotating” and “spindling,” it is necessary to save the positions of the axes in the controller and buffer them until the next switchover. Incorrect positions of the axes can occur as a consequence of errors. In the case of another mechanism, shaft and spindle are respectively driven by a dedicated motor. If the object is only to rotate the shaft, the two motors are operated synchronously. However, during this synchronous running it is scarcely possible to avoid the lag error, and thus also a mutual shifting of the shaft and spindle relative to one another. By way of example, this results in undesired displacement of the position of the cambering heads. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a device for variably driving a hollow shaft with an inner spindle which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which enables exact synchronous running, but also separate actuation of the hollow shaft and the shaft/spindle. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a variable drive apparatus, comprising:
         a hollow shaft;   an inner shaft or spindle supported on said hollow shaft and lying inside said hollow shaft;   a drive gear constructed as a differential speed gear selected from the group consisting of a planetary gear and a harmonic drive gear, said drive gear coupling said hollow shaft to said inner shaft or spindle; and   a drive device connected to said drive gear;   wherein said drive gear is coupled between said hollow shaft and said inner shaft or spindle for synchronously driving said hollow shaft and said inner shaft or spindle with only said drive device.       

     The hollow shaft and the inner shaft or spindly are particularly suited for driving moving component parts of a tire building machine. 
     In other words, the objects of the invention are achieved by virtue of the fact that the hollow shaft is coupled to the inner shaft or spindle via a planetary gear or a harmonic drive gear that is respectively constructed as differential speed gear, such that synchronous running of hollow shaft and shaft or spindle is performed via a single drive device. 
     The coupling of the hollow shaft to the shaft or spindle via a planetary gear or a harmonic drive gear enables a single drive device to be used for synchronous running of the hollow shaft and shaft or spindle, it being possible to set the hollow shaft and shaft or spindle rotating at an exactly corresponding speed through the design of the speed transformations provided. 
     In accordance with a preferred embodiment of the invention, the drive device for synchronous running is that drive device which drives the hollow shaft, in particular via an appropriate speed transformation. The second drive device provided in the case of an inventive device acts on the sun wheel of the planetary gear. These measures permit the speed ratios to be selected and the number of the gear components required for the speed transformation, such as toothed wheels and toothed belts, to be kept low, and reliable and long-lasting functioning of the device to be ensured. 
     A design that is very favorable with regard to the speed transformation of the device results when the drive device that drives the hollow shaft also acts on the planet pinion carrier and drives the latter. 
     In a preferred design of the gear arrangement belonging to the inventive device, it is provided that, for synchronous running of hollow shaft and shaft or spindle in conjunction with a fixed sun wheel of the planetary gear, the rotary movement of the hollow shaft is transmitted via the hollow wheel to the planet pinion carrier and from the latter to the shaft or spindle, this being done with appropriate speed transformation. In the case of this embodiment, it is provided for a rotary movement of the shaft or spindle in conjunction with a fixed hollow shaft and fixed hollow wheel of the planetary gear that the sun wheel is driven such that the rotary movement thereof is transmitted via the planet pinion carrier to the shaft or spindle. 
     The number of the gear components provided is particularly low in the case of a design in which, for synchronous running of hollow shaft and shaft or spindle in conjunction with a fixed sun wheel of the planetary gear, a rotary movement of the driven planet pinion carrier is transmitted via the hollow wheel and the housing of the planetary gear to the shaft or spindle, this being done with appropriate speed transformation. In the case of this design variant, it is provided for a rotary movement of the shaft or spindle in conjunction with a fixed hollow shaft and fixed planet pinion carrier of the planetary gear to drive the sun wheel whose rotary movement is transmitted via the planet pinion to the hollow wheel and the housing of the planetary gear and via these parts to the shaft or spindle. 
     Motors are particularly suitable as drive devices. It is also possible, however, to provide a pneumatic rotary cylinder as a drive device for the sun wheel of the planetary gear. This drive device is particularly suitable for the case when only small rotary angles are required for the shaft or spindle. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a device for the variable driving of a hollow shaft with an internal spindle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       DETAILED DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a schematic illustration of an exemplary embodiment of the device according to the invention; and 
         FIG. 2  is a schematic illustration of an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The inventive device permits, in a particularly reliable and expedient way, a synchronous drive of a hollow shaft and an inner shaft or spindle located therein and supported on the hollow shaft. A preferred use of the device is therefore in the case of tire building machines, the hollow shaft sets the tire building machine in rotation, for example, in order to roll up the belt package of a pneumatic vehicle tire, for example, and the spindle shifting cambering heads, for example, in an axial direction compared with one another in a known way. 
     Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, the apparatus according to the invention includes a hollow shaft  1 , an inner shaft or internal spindle  2 , and a bearing  3  for the hollow shaft  1 . The spindle  2 , which may also be referred to as an inner shaft, is supported on the hollow shaft  1  in a way not shown such that during a rotary movement of the shaft  1  the spindle  2  is simultaneously set rotating. A toothed wheel  4  is permanently connected to the shaft  1 . The toothed wheel  4  engages with a further toothed wheel  5  that can be set rotating by a motor M 2 . A further toothed wheel  6 , permanently connected to the shaft  1 , is coupled via a toothed belt  7  to a toothed wheel  8  that is seated on a housing  10  of a planetary gear  11  and is permanently connected thereto.  9  denotes the bearing for the housing  10  of the planetary gear  11 . A hollow wheel  12  that rolls on the inside of the housing  10  and is permanently connected thereto engages with at least one planet pinion  14  that is arranged on a planet pinion carrier  15  that is guided to the outside from the housing  10 , in a fashion aligned with the axis of the planetary gear  11 , and carries a toothed wheel  16  here. The toothed wheel  16  is coupled via a toothed belt  17  to a toothed wheel  18  that is permanently connected to the spindle  2 . 
     The sun wheel  13  of the planetary gear  11  can be driven by means of a motor M 1  located outside the planetary gear  11  and engages in the planet pinion  14 . 
     There are a multiplicity of possible ways of operating the device, in particular by means of a separate or a common operation of the motors M 1  and M 2 . Three important operating modes are explained in more detail below by way of example. Since the spindle  2  located in the hollow shaft  1  is supported against the hollow shaft  1 , one important operating mode is that in the case of which the hollow shaft  1  and the spindle  2  are set rotating synchronously in order, for example, to set a tire building drum rotating via the hollow shaft  1 , the invention being, however, for the spindle  2  not to change its position relative to the hollow shaft  1 , for example in order to maintain the position of cambering heads. The motor M 2  is taken into operation for this operating mode and sets the shaft  1  rotating at the speed of n w  via the toothed wheels  4  and  5 . The toothed wheel  6  connected to the shaft  1  transmits the rotary movement of the shaft  1  via the toothed belt  7  to the toothed wheel  9 , and thus to the housing  10 , which is set rotating at a speed n 3 . The hollow wheel  12  permanently connected to the housing  10  sets rotating the planet pinion  14 , which is engaged with it and in this case revolves relative to the fixed sun wheel  13  along the hollow wheel  12  and between the hollow wheel  12  and the sun wheel  13 . The planet pinion carrier  15  is thereby set rotating and its crank part, which is aligned with the axis of the sun wheel  13 , sets rotating at a speed n 2  the toothed wheel  16  that transmits the rotary movement via the toothed belt  17  to the toothed wheel  18 , which is permanently connected to the spindle  2  and sets the latter rotating at the speed n s . 
     The following relationship holds for the planetary gear  11 :
 
 n   1   −i×n   2 −(1 −i )× n   3 =0  (1)
 
where
         i is the speed transformation of the planetary gear  11 ,   i 1  is the speed transformation of the shaft  1  in relation to the housing  10  of the planetary gear  11 ,   i 2  is the speed transformation of the spindle  2  in relation to the planet pinion carrier  15  of the planetary gear  11         

     The speed n 1  of the sun wheel  13  of the planetary gear  11  is zero during stoppage of the motor M 1  when only the motor M 2  is being operated, and it holds that: 
     
       
         
           
             
               
                 
                   
                     
                       i 
                       - 
                       1 
                     
                     i 
                   
                   = 
                   
                     
                       
                         
                           n 
                           2 
                         
                         
                           n 
                           3 
                         
                       
                       ⁢ 
                       and 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         i 
                         1 
                       
                     
                     = 
                     
                       
                         
                           
                             n 
                             3 
                           
                           
                             n 
                             w 
                           
                         
                         ⁢ 
                         and 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           i 
                           2 
                         
                       
                       = 
                       
                         
                           
                             
                               n 
                               2 
                             
                             
                               n 
                               s 
                             
                           
                           ⁢ 
                           and 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           1 
                         
                         = 
                         
                           
                             n 
                             w 
                           
                           
                             n 
                             s 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     The following relationship holds for the speed transformations i 1 , i 2  between the shaft  1  and the spindle  2 , on the one hand, and the planetary gear  11 , on the other hand: 
     
       
         
           
             
               
                 
                   
                     i 
                     1 
                   
                   = 
                   
                     
                       i 
                       2 
                     
                     × 
                     
                       
                         i 
                         - 
                         1 
                       
                       i 
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     From the transformations, the following transmission ratio results for the motor M 1  to the spindle  2 : 
     
       
         
           
             
               
                 
                   
                     i 
                     ges 
                   
                   = 
                   
                     i 
                     × 
                     
                       i 
                       2 
                     
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     
                       
                         n 
                         1 
                       
                       
                         n 
                         s 
                       
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     For the above-mentioned case in which the shaft  1  and the spindle  2  are to be set rotating synchronously with a sole operation of the motor M 2 , the speed n w  of the shaft is equal to the speed n s  of the spindle  2 . The speed ratios of the participating toothed wheels and toothed belts are adapted correspondingly to one another. 
     In the case of a further possible operating mode, only the spindle  2  is set rotating in relation to the hollow shaft  1 . In this case, the motor M 1  operates the sun wheel  13  of the planetary gear  11 , and the hollow wheel  12  is the fixed component part of the planetary gear  11 . The planet pinion  14 , which engages both with the sun wheel  13  and with the hollow wheel  12 , runs between sun wheel  13  and hollow wheel  12 , and thereby sets the crank-like planet pinion carrier  15  rotating at the speed of n 2 . The planet pinion carrier  15  operates the toothed wheel  16  that sets rotating via the toothed belt  14  the toothed wheel  18  that rotates the spindle  2 . Also possible is a common operation of the motors M 1  and M 2  in order to set the shaft  1  rotating non-synchronously in relation to the internal spindle  2 . Depending on the direction of rotation of the servomotors M 1  and M 2 , there are a multiplicity of possible operating modes of the gear arrangement, in particular through selection of the speed n w  of the shaft  1 , and the speed n 1  of the sun wheel  13 , the speed n 2  of the planet carrier  15 , and the speed n s  of the spindle  2 . 
     In the schematic, shown in  FIG. 2 , of a further embodiment, once again  1  denotes the hollow shaft,  2  the internal spindle that is supported on the hollow shaft  1  in a way not shown, and  3  the bearing for the hollow shaft  1 . Permanently connected to the shaft  1  is a toothed wheel  22  that is coupled via a toothed belt  23  to a further toothed wheel  24  that can be set rotating by a motor M 2 . The motor M 2  simultaneously drives the planet pinion carrier  15  of the planetary gear  11 , which is also present in the case of this embodiment. The planet pinion carrier  15  sets moving at least the one planet pinion  14  between the hollow wheel  12 , which is permanently connected to the housing  10  of the planetary gear  11 , and the sun wheel  13 . With the interposition of a toothed belt  20 , a toothed wheel  19  arranged on the outside of the housing is connected to a toothed wheel  21  that is permanently connected to the spindle  2 . The second motor, the motor M 1 , is provided for the purpose of driving the sun wheel  13  of the planetary gear  11 . n w  denotes the speed of the hollow shaft  1 , n s  the speed of the spindle  2 , n 1  the speed of the sun wheel  13  of the planetary gear  11 , n 2  the speed of the planet pinion carrier  15  of the planetary gear  11 , and n 3  the speed of the housing  10  of the planetary gear  11 . 
     In the case of this design variant, as well, there are a multiplicity of possible ways of operating the device by separate or common operation of the motors M 1  and M 2 . Only the sole operation of the motor M 2  and the sole operation of the motor M 1  are briefly described below in this case. Given an appropriate setting of the speed ratios of the participating toothed wheels and toothed belts, the sole operation of the motor M 2  effects a synchronous movement of the hollow shaft  1  and the spindle  2  with corresponding speeds and n w  and n s . Via the toothed wheel  24 , the toothed belt  23  and the toothed wheel  22 , the motor M 2  sets the hollow shaft  1  rotating at the speed n w . Given a fixed sun wheel  13 , the motor M 1  is not operating and the motor M 2  sets the planet pinion carrier  15  and thus the planet pinion  14 , moving simultaneously at the speed n 2 . The toothed wheel  19  is thereby set rotating via the housing  10 , this rotary movement being transmitted via the toothed belt  20  to the toothed wheel  21 , and from there to the spindle  2 . 
     If the aim is only for the spindle  2  to be set rotating relative to the hollow shaft  1 , when the motor M 2  is stationary the motor M 1 , which drives the sun wheel  13  of the planetary gear  11 , is taken into operation, the planet pinion carrier  15  now being the fixed component part of the planetary gear  11 . The sun wheel  13  sets rotating the planet pinion  14  that transmits its movement to the hollow wheel  12  and thus to the housing  10  and the toothed wheel  19 . Via the toothed belt  20 , the toothed wheel  19  is coupled to the toothed wheel  21  that sets the spindle  2  rotating. The following relationship holds for the planetary gear  11 .
 
 n   1   −i′×n   2 −(1 −i )× n   3 =0  (5)
 
where
         i′ is the speed transformation of the planetary gear  11 ,   i 1 ′ is the speed transformation of the shaft  1  in relation to the planet pinion carrier  15  of the planetary gear  11 ,   i 2 ′ is the speed transformation of the spindle  2  in relation to the housing  10  of the planetary gear  11 .       

     In order for the shaft  1  and the spindle  2  not to move relative to one another during the stoppage of the motor M 1 , n 1  is equal to zero, and the following holds true: 
     
       
         
           
             
               
                 
                   
                     
                       
                         i 
                         ′ 
                       
                       - 
                       1 
                     
                     
                       i 
                       ′ 
                     
                   
                   = 
                   
                     
                       
                         
                           n 
                           2 
                         
                         
                           n 
                           3 
                         
                       
                       ⁢ 
                       and 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         i 
                         1 
                         ′ 
                       
                     
                     = 
                     
                       
                         
                           
                             n 
                             3 
                           
                           
                             n 
                             w 
                           
                         
                         ⁢ 
                         and 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           i 
                           2 
                           ′ 
                         
                       
                       = 
                       
                         
                           
                             
                               n 
                               2 
                             
                             
                               n 
                               s 
                             
                           
                           ⁢ 
                           and 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           1 
                         
                         = 
                         
                           
                             n 
                             w 
                           
                           
                             n 
                             s 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
     The following (7) holds true for the speed transformations i 1 ′, i 2 ′ between the shaft  1  and the spindle  2 , on the one hand, and the planetary gear  11 , on the other hand: 
     
       
         
           
             
               
                 
                   
                     
                       
                         i 
                         2 
                         ′ 
                       
                       = 
                       
                         i 
                         1 
                         ′ 
                       
                     
                     x 
                   
                   ⁢ 
                   
                     
                       
                         i 
                         ′ 
                       
                       - 
                       1 
                     
                     
                       i 
                       ′ 
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
           
         
       
     
     A number of further possible operating modes are also feasible in the case of this design variant, depending on direction of rotation of the motors M 1  and M 2 , and dependent on the choice of speeds. 
     Only small angles of rotation of the spindle  2 , for example an angle of 30° to 45°, are required for specific applications. For the case in which there is no need to prompt complete revolutions of the spindle  2 , the motor M 1  can also be replaced by a pneumatic rotary cylinder. 
     If large speed ratios are required, the planetary gear shown can be replaced by a so-called harmonic drive gear. 
     There are a number of further advantageous applications of the inventive device in the case of tire building machines. These include, for example, carrying out the collapse of a so-called tilting drum on the first stage of tire building machines. In the case of a tilting drum, a switchover is made between the winding diameter and the diameter for removal of the carcass. This is performed by rotating an inner and an outer shaft, it being possible to drive the shafts in accordance with the invention. A further possible application exists in the case of adjusting diameters on building drums of tire building machines. In this case, it is possible to apply to the inner shaft a spindle that is supported on the outer shaft, such that it is possible to adjust the outer diameter of a segmented drum via a cone or lever, which is arranged around the outer shaft, in order to be able to fabricate tires of different sizes. In the case of tire building machines, the width of building drums can be adjusted by applying to the inner shaft a spindle that is supported on the outer shaft.