Abstract:
The invention relates to a device for supplying a hydraulic medium to a rotatably mounted drive element in a transmission case, the hydraulic medium being routed to a channel in the drive element by way of at least one channel in a coaxially adjacent element which corresponds to the drive element. Structurally favorable and reliable supply with hydraulic medium is achieved in that the drive element is nonrotatably connected to the other element and that the contact connection is at least one unthreaded conduit which is inserted tightly into the two channels and which extends directly from the element to the drive element.

Description:
This application is a §371 application of PCT/EP03/012112, which claims priority from DE 198 57 710 A 1. 
   BACKGROUND 
   The invention relates to a device for supplying a hydraulic medium to a drive element rotatably mounted in a transmission case. 
   In general, drive elements rotatably mounted in a transmission case—only one example being the pulley set of continuously variable transmission in a motor vehicle, with a hydraulically adjustable loose pulley which can be axially moved relative to the fixed pulley—are transmitted by way of channels in the shaft which bears the drive element by a coaxially configured element which is connected to the hydraulic control. In particular, when several separate channels are necessary for hydraulic control, this results in a significant production engineering effort and a considerable weakening of the indicated shaft due to the required shaft bores. 
   The object of the invention is to propose a device of the generic type which enables reliable hydraulic supply of a drive element without shaft holes. 
   The drive element of the invention is nonrotatably connected to the other element and that the contact connection is at least one unthreaded conduit which is inserted tightly into the two channels and which extends directly from the element to the drive element. At least one unthreaded conduit turns with the element which supplies the hydraulic medium; shaft bores can accordingly be omitted. Furthermore, at least one unthreaded conduit forms a connection which to a limited degree allows universal movements and axial compensation between the drive element and the other element; this results in supply of the hydraulic medium to the drive element which is reliable even with unfavorable tolerance pairings and operating conditions. (temperature, load) or axial slip. Another major advantage is that if necessary the supplying element can be a component of the transmission which also performs other functions (for example, routing the hydraulic medium through a coaxially adjacent gear which turns with the drive element). 
   At least one unthreaded conduit can extend radially within a roller bearing which is provided between the drive element and the adjacently located element. This makes possible supply of the drive element by way of at least one unthreaded conduit even if support is indicated between the drive element and the other element for transmission engineering purposes. 
   Preferably the inner ring of the roller bearing can sit on the neck of the drive element and at least one unthreaded conduit can run in a corresponding recess of the neck. The unthreaded conduit can thus be partially integrated into the drive element without added construction effort and space consumption. 
   Simple axial locking is achieved by the unthreaded conduit being provided with a radial projection by means of which it is held on the front between the inner ring of the roller bearing and the following drive element. 
   Furthermore, for easy installation of the transmission element the unthreaded conduit on the two ends can bear gaskets for sealing with the adjoining channels in the drive element and the other element. This makes it possible to easily assemble the transmission elements and enables routing of the hydraulic medium which is insensitive to vibrations and which is guided hermetically sealed even in the event of limited universal and axial relative movements. 
   Especially preferably provision can be made for several unthreaded conduits which are distributed over the periphery of the drive element and which correspond to the appropriate channels in the drive element and in the other element. Either at the same time larger hydraulic amounts or with separate channels different hydraulic functions can be controlled by way of the unthreaded conduits. 
   Furthermore, the annular hydraulic chamber can be supplied using an actuating piston for movement of the drive element by way of the channels and unthreaded conduits. By using unthreaded conduits, in addition to the aforementioned advantages, channel routing within the drive element can also be simplified, because the unthreaded conduits if necessary enable direct supply of the hydraulic medium to the annular hydraulic chamber. 
   Advantageously there can be spline-teeth as the nonrotatable connection between the drive element and the other element; they are configured as an unthreaded connection radially within the roller bearing on the neck of the drive element and on the annular projection of the other element. This makes possible a structurally favorable and compact transmission design which moreover yields further simplification of assembly and axial tolerance compensation. 
   Finally, in one preferred application of the invention the drive element can be a driven pulley set of a continuously variable transmission for motor vehicles and the other element can be the differential gear case of a torsen differential, also known as a worm gear differential, the output to the axle of the motor vehicle extending through the hollow shaft of the pulley set and the transmission ratio of the pulley set to the looping means being controllable by way of channels and the unthreaded conduits. The concept of a torsen differential is known in mechanical engineering and especially in transmission engineering. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The FIGURE shows in a longitudinal section a device for hydraulic supply of the driven pulley set of a continuously variable transmission for a motor vehicle. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the drawing,  10  generally designates a drive assembly which is rotatably mounted in an only partially shown transmission case  12  and which is composed essentially of an only partially shown driven pulley set  14  as the drive element and a torsen differential  16  which is located coaxially adjacent to it as the other element. 
   The pulley set  14  is one part of the continuously variable transmission for motor vehicles and interacts in the conventional manner by way of a chain or an articulated belt with a drive pulley set (not shown) located on the input shaft of the transmission. 
   The driven pulley set  14  has a fixed pulley (not shown in the drawings) which forms a common component with an adjoining hollow shaft  18 . The fixed pulley is supported to be axially immovable in one wall of the transmission case  12  by way of a double-row taper roller bearing. 
   On the hollow shaft  18  the loose pulley  20  is guided to be axially movable, a spline connection which is designated as  22  producing positive locking in the peripheral direction. Here the loose pulley  20  as shown in the drawings to the left is pretensioned by means of a helical compression spring  24  which is supported on the guide section  26 . The guide section  26  is connected permanently to the hollow shaft  18  by an annular laser weld at  28 . 
   SUMMARY OF THE INVENTION 
   To move the loose pulley  20  relative to the fixed pulley which is not shown, between the guide section  26  and the loose pulley  20  by means of annular sheets  34 ,  35  which have been welded together and which are fixed on the loose pulley  20 , two annular hydraulic chambers  30 ,  32  are formed which are sealed by gaskets which are generally designated as  36  and are divided by an annular actuating piston  38 . The actuating piston  38  which is permanently connected to the guide section  26  by way of an edged connection  40  acts as the reaction element to the corresponding axial adjustment of the loose pulley  20  when the hydraulic chambers  30 ,  32  are pressurized accordingly. 
   The guide section  26  has an annular neck  42  with the inner ring  44  of the roller bearing or ball bearing  46  sitting on its outer periphery. The ball bearing  46  is held in the transmission case wall  48  in a corresponding recess  50  and thus acts as another pivot bearing for the pulley set  14 . 
   On the inside periphery of the annular neck  42 , for example in the plane of rotation of the ball bearing  46 , spline-teeth designated as  52  in general are machined and interact with the corresponding spline-teeth on the sleeve-shaped projection  54  of the differential gear case  56  of the torsen differential  16  as a driving connection. 
   In the differential gear case  56 , three worm gear pairs  58  which are distributed uniformly in the conventional manner over its periphery are supported and engage the corresponding driven gears  60 ,  62 . The driven gears  60 ,  62  sit nonrotatably on driven shafts  64 ,  66 , of which the driven shaft  64 , through the hollow shaft  18  by way of a drive pinion which is not shown and a front differential, drives the front wheels of the motor vehicle, and the driven shaft  66 , by way of a connected universal shaft and the rear differential, drives the rear wheels of the motor vehicle. 
   The drive shaft  64 , in addition to the support which is not shown, is supported in the area of the drive pinion in one loading direction by way of an axial bearing  68  on the hollow shaft  18 , its one retainer ring  70  being held on a locking ring  74  which is forced into an annular groove  72 . 
   The torsen differential  16  and its operating parts are lubricated with lubricating oil from the front differential which is not shown, a feed channel  76  which is provided in the driven shaft  64  discharging into the differential gear case  56 . The return of the lubricating oil takes place in the opposite direction through the hollow shaft  18 , in addition to the axial bearing  68  two radially supporting needle bearings  78  (only one needle bearing  78  is shown, the second is positioned approximately in the area of the fixed pulley) between the hollow shaft  18  and the driven shaft  64  being lubricated. 
   The torsen differential  16  is made fully encapsulated in order to ensure only lubrication of the described operating parts with the differential lubricating oil (a hypoid oil). For this purpose, there is an annular cover part  80  which encloses the differential gear case  56  and which seals the differential gear case  56  to the outside in conjunction with gaskets  82 . Another gasket  84  is inserted in the area of the spline-teeth  52  between the hollow shaft  18  and the sleeve-shaped projection  54  of the differential gear case  56 . 
   The front seal of the differential gear case  56  finally effects a tubular piston ring insert  86  with a connecting flange  88  with another gasket  56  which it is screwed (screws  92 ) tightly to the differential gear case  56  and the axial seal (not shown). 
   The piston ring  86  and accordingly the differential gear case  56  are pivotally mounted directly following the connecting flange  88  by means of another roller bearing or ball bearing  94  in a corresponding receiver  96  on the housing, the annular section  97  of the piston ring insert  86  which is provided with piston rings  98  in the corresponding outside grooves  99  projecting, as is apparent, into a cylindrical hole  100  of the housing part  102  which has the receiver  96 . 
   The rotationally symmetrical sealing sleeve  104  which is inserted into the piston ring insert  86  projects axially over the annular section  97  and is sealed to the housing part  102  by way of a rotary shaft seal  124  so that hydraulic medium cannot emerge from the channels  106 ,  108 . 
   The hydraulic chambers  30 ,  32 ,  32   a  can be supplied on alternating sides with a pressurized hydraulic medium for control of the driving transmission of the continuously variable transmission by way of the piston ring insert  86  and the rotationally symmetrical sealing sleeve  104  which is inserted into it, by way of the illustrated channels  106  which are each provided with a uniform reference number in the housing part  102 , by way of the channels  108  which are formed by the longitudinal grooves in the piston ring insert  86 , by way of the channels  110  which are machined in the differential gear case  56 , and finally by way of the corresponding channels  112  in the guide section  26  (only one channel  112  is shown in the sectional view of the drawing). 
   The hydraulic connection between the channels  110  in the differential gear case  56  and the channels  112  in the guide section  26  is formed by three unthreaded conduits  114 . The unthreaded conduits  114  each project with the interposition of gaskets  116  on the one hand into a corresponding front recess of the guide section  26  and of the differential gear case  56 , said unthreaded conduits being guided through recesses  118  of the guide section  26 , which are open radially to the outside and which are semicircular when viewed in cross section, within the inner ring  44  of the ball bearing  46 . 
   The unthreaded conduits  114  (to move the loose pulley, as stated, there are three unthreaded conduits  114  which are distributed uniformly over the periphery of the guide section  26  and of the differential gear case  56 ) are held by means of radial projections  120  which are molded onto them between the inner ring  44  and the front recess  122  of the guide section  26 . Axial guidance of the unthreaded conduit can also be selectively guaranteed by contact of the end surfaces.