Patent Abstract:
A connection ( 4 ) of a first ( 2 ) to a second ( 3 ) cylindrical component for the transfer of circumferential and axial forces. The first component ( 2 ) has locking elements ( 9   a ) arranged on its circumference and at the end, the second component ( 3 ) has windows ( 12 ) associated with the locking elements ( 9   a ), and the first and second components ( 2, 3 ) can be plugged one into the other at the ends to form a positive interlock between the locking elements ( 9   a ) and the windows ( 12 ).

Full Description:
This application is a National Stage completion of PCT/EP2007/059162 filed Sep. 3, 2007, which claims priority from German application serial no. 10 2006 044 109.5 filed Sep. 20, 2006. 
     FIELD OF THE INVENTION 
     The invention concerns a connection of a first to a second cylindrical component and a method for assembling the two components. 
     BACKGROUND OF THE INVENTION 
     Cylindrical components, especially hollow cylinders, stepped cylinders or pot-shaped cylinders, are used for example in automatic transmissions for motor vehicles. Such cylinders accommodate planetary gearsets and/or shift elements in the form of clutches or brakes, and can also comprise internal or external teeth for connection to other components such as inner or outer disks. A component of this type is disclosed in the older, not previously published utility-model application DE 20 2006011424.6 by the present applicant as a cylinder, for example configured as an inner disk carrier. In that case the cylinder encloses a planetary gearset on the input side and two shift elements. Such a cylinder is produced as a deep-drawn component made from a deep-drawing steel, so that the length of the cylinder is limited by production technology considerations. In modern transmission developments cylindrical components are needed, whose axial length is larger than can be produced by conventional deep drawing methods. In such cases components of that type can be made by pressure rolling, a process known for example from DE 43 13 648 C2 or EP 0 955 110 B1. However, cylindrical components produced by pressure rolling are more expensive to manufacture. 
     SUMMARY OF THE INVENTION 
     The purpose of the present invention is to provide a cylindrical component of the required length, which can be produced inexpensively. 
     According to the invention a plug-in connection is provided between two cylindrical components which, together, form a component of longer axial length. The first component has locking elements arranged at its front end and the second component has corresponding windows into which the front-end locking elements can be plugged by axial movement. This produces a compact joint between two cylindrical components, which can transfer both circumferential forces and axial forces (in the compression direction). The two components form an overlap zone of larger wall thickness corresponding to the sum of the wall thicknesses of the two individual components. Compared with known connections, for example by interlocking teeth, the connection according to the invention is very small in the radial direction, i.e. it has advantages in relation to the radial space occupied. 
     The front-end locking elements are preferably formed as tabs which stand out relative to the cylinder body and so form end or crown teeth. The corresponding windows with which the crown teeth are brought into engagement are positioned in the second component in a transition zone from a larger to a smaller inside diameter. This enables the front-end teeth to be pushed in the axial direction into the windows until the front edges of the crown teeth encounter the windows. During this insertion process the two components are pushed toward one another through the overlap zone in a telescopic manner. 
     According to a preferred embodiment, in the overlap zone on the second component, i.e. the outer component, bracing tabs are cut free and on the first component, i.e. the component arranged on the inside, windows are cut out, in which the supporting tabs engage with interlock and thus transfer axial forces in the opposite direction (the tension direction). In this way the connection according to the invention can transfer axial forces in both directions, i.e. on the one hand by means of the end surfaces of the end teeth and on the other hand by means of the end surfaces of the bracing tabs. 
     According to a preferred embodiment the bracing tabs have an initial shape which allows the inner component to be pushed into the outer component. By pressing from outside, for example by means of a device, the initial shape is brought to a final shape which is made possible by a type of snap effect, i.e. from a convex to a slightly concave shape. 
     Alternatively, the bracing tabs can be made as springy tongues which, when the inner component is inserted, are first pushed outward and in the end position of the two components clip back into the windows in the manner of a catch connection. This variant allows assembly without any device that grips from the outside. The number of bracing tabs and front-end locking elements (crown teeth) is different: since the crown teeth also transfer circumferential forces while in contrast the bracing tabs do not, in a preferred embodiment about thirty crown teeth are provided, whereas for the bracing tabs only a smaller number are needed, which is matched to the axial forces to be transferred. 
     In an advantageous embodiment the two components can be made from different materials, these respective materials being chosen in accordance with the different demands on the first and second component. 
     In a preferred embodiment both components can be made as deep-drawn components. This has advantages in relation to production costs, especially compared with pressure rolling. 
     The connection according to the invention can be used particularly advantageously in motor vehicle automatic transmissions, i.e. for a cylinder composed of two part-cylinders in an automatic transmission for accommodating planetary gearsets and/or shift elements. In this application it is advantageous to make the first component, i.e. the first part-cylinder from a non-magnetizable material, for example aluminium, an aluminium alloy or an austenitic steel. This brings the advantage that a speed sensor that works by the well-known Hall effect can be arranged in the area of the first component, which is not possible with ordinary deep-drawing steels that can be magnetized. Thus, the sensor can detect the rotation speed of a transmission component such as a carrier shaft of a planetary gearset. 
     According to the method, the two components are orientated end-to-end and pushed one into the other until the front faces of the crown teeth encounter the windows of the other component. Then, locking takes place by the bracing tabs in the other, opposite axial direction. Here, two variants are possible: the first provides that the bracing tabs are pressed into the windows of the other component by means of a device which grips from the outside, and during this the bracing tabs snap from a convex initial shape to a concave final shape, thereby axially bracing the two components together. 
     In a second, preferred variant the axial locking takes place automatically, i.e. the bracing tabs made as elastic tongues spring inward when the inner component has been inserted, and clip into the windows. No other device is needed for this. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An example embodiment of the invention is illustrated in the drawing and will be described in greater detail below. 
       The figures show: 
         FIG. 1 : A cylinder, consisting of a first and a second part-cylinder, for an automatic transmission 
         FIG. 2   a : Partial section through the first part-cylinder 
         FIG. 2   b : Partial view of the first part-cylinder in the direction A 
         FIG. 3   a : Partial section through the second part-cylinder 
         FIG. 3   b : View of the second part-cylinder in the direction B 
         FIG. 4   a : Connection of the two part-cylinders according to the invention, showing the detail X in  FIG. 1   
         FIG. 4   b : Another view of the detail X. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows an axial section through a cylinder  1  that can be used in an automatic transmission of a motor vehicle to accommodate a planetary gearset and shift elements (none of them shown). The cylinder  1  is composed of two part-cylinders, a first part-cylinder  2  and a second part-cylinder  3 , which are connected firmly to one another by a plug-in joint  4 . In the outer, end area of the part-cylinder  2  is arranged a guide disk  5 , which is connected to the first part-cylinder  2  by means of locking teeth  5   a ,  2   a . The guide disk  5  is part of the planetary gearset (not shown). At the opposite end of the cylinder  1  a ring gear  6  is connected fixed to the part-cylinder  3 , i.e. by means of a weld seam  7 , although locking teeth would also be possible in place of the weld seam  7 . In the area of the first part-cylinder  2  is arranged a speed sensor  8  which consists of a static sensor component  8   a  positioned outside the part-cylinder  2  and a rotating magnetic ring  8   b  arranged inside the first part-cylinder  2 . The first part-cylinder  2 , which is therefore between the sensor component  8   a  and the rotating magnetic ring  8   b , is made from a non-magnetic material, preferably aluminium, an aluminium alloy or an austenitic steel such as V4A. Thus the speed sensor  8 , which works according to the well-known Hall effect, is functional. The second part-cylinder  3  is made from an ordinary commercial deep-drawing steel and can therefore be welded to the ring gear  6 . Preferably, both part-cylinders  2 ,  3  are deep-drawn components, i.e. made by deep drawing from a sheet blank. 
       FIGS. 2   a  and  2   b  show, respectively, the first part-cylinder  2  in section and seen from above (in the direction A). At the front, i.e. in the area of the joint  4  ( FIG. 1 ) the first part-cylinder  2  has end- or crown-teeth  9 , consisting of tabs or teeth  9   a  chamfered at the end, with gaps  9   b  arranged between them. Furthermore, on the circumference of the part-cylinder  2  are arranged rectangular or square openings in the form of windows  10 , whose purpose will be explained below. 
       FIGS. 3   a  and  3   b  show the part-cylinder  3  in section and seen from above (in the direction B). The second part-cylinder  3  has a front edge  3   a  and, in its end area, an inside diameter D 1  which corresponds to the outside diameter of the first part-cylinder  2 , and a reduced inside diameter D 2  which corresponds to the inside diameter D 2  of the first part-cylinder  2 . The transition from the larger inside diameter D 1  to the smaller inside diameter D 2  is shown as a beveled section  11 . In the area of the beveled section  11 , distributed around the circumference, rectangular openings in the form of windows  12  are cut out of the cylinder surface of the second part-cylinder  3 , the width of these windows (in the circumferential direction) corresponding to the width of the teeth  9   a  of the end tooth array  9  of the first part-cylinder  2 . In addition, in the cylinder surface of the second part-cylinder  3  tongues  13 , so-termed bracing tabs, are cut free, i.e. they are surrounded by an approximately U-shaped gap  14 . As can be seen in  FIG. 3   a  the bracing tabs, seen in cross-section, are convexly curved and project outward a little above the gap opening  14 . The form of the bracing tabs  13  illustrated is a so-termed initial shape, i.e. a shape before the two part-cylinders  2 ,  3  are assembled together. This enables the first part-cylinder  2  to be pushed in the axial direction into the second part-cylinder  3 , so that the slightly chamfered teeth  9   a  can engaged with the windows  12 . The windows  12  have abutment surfaces  12   a  against which the ends  9   c  of the teeth  9  come into contact. 
       FIGS. 4   a  and  4   b  show the detail X from  FIG. 1 , i.e. the connection  4  of the two part-cylinders  2 ,  3 , on an enlarged scale. The same parts are given the same indexes. The front-end areas of the part-cylinders  2 ,  3  pushed into one another form an overlap zone ü which extends from the front surfaces  9   c  of the end teeth  9  as far as the front edge  3   a  of the second part-cylinder  3 . The initial shape of the bracing tab  13  is here shown by broken lines. The bracing tab  13  is pressed inward by a device (not shown) to position  13 ′ (continuous line) so that its front surface  13   a  presses against the corresponding contact surface  10   a  of the window  10 , whereby the two part-cylinders  2 ,  3  are axially braced. This joint by the bracing tabs  13 ′ of the second part-cylinder  3  can transfer axial tensile forces between the two part-cylinders  2 ,  3 . Compression forces in the axial direction are transferred by the end teeth  9 . Circumferential forces between the two part-cylinders  2 ,  3  are also transferred by the end teeth  9 , but via the lateral surfaces of the teeth  9   a  which, in  FIG. 4   a , are shown as a cross-hatched area F. 
     As a variation from the example embodiment illustrated, the bracing tabs  13  can also be made as elastically springy tongues which, when the first part-cylinder is inserted into the second part-cylinder, are first pushed outward by the end surface of the first part-cylinder and—when the end faces  9   c  have come up against the abutment surfaces  12   a —spring back into the windows  10 . 
     Indexes 
     
         
           1  Cylinder 
           2  First part-cylinder 
           2   a  Locking teeth 
           3  Second part-cylinder 
           3   a  Front edge 
           4  Connection (between the first and second part-cylinders) 
           5  Guide disk 
           5   a  Locking teeth 
           6  Ring gear 
           7  Weld seam 
           8  Speed sensor 
           8   a  Sensor component 
           8   b  Magnetic ring 
           9  End teeth 
           9   a  Tooth 
           9   b  Gap 
           9   c  End surface 
           10  Window 
           11  Beveled section 
           12  Window 
           12   a  Abutment surface 
           13  Bracing tab 
           13 ′ Bracing tab (final shape) 
           14  Gap 
         D 1  Outside diameter (first part-cylinder) 
         D 2  Inside diameter (first part-cylinder) 
         F Force transfer area 
         ü Overlap zone

Technology Classification (CPC): 8