Spline connection

Abstract

A motor vehicle 10 includes a hydromechanical powersplit transmission 11 having a hydraulic pump motor unit drive shaft 44 and a gear 76 . The shaft 44 and gear 76 are drivingly connected together with a spline connection 160 . The spline connection 160 includes an internal spline connector 161 and an external spline connector 162 . Each spline connector 161, 162 includes a spline portion 166, 174 and a generally smooth portion 168, 175 adjacent its spline portion. During assembly, generally smooth portion 168 of the internal spline connector 160 engages and guides spline portion 174 of the external spline connector 162 to longitudinally and circumferentially align the spline portions 174 and 166 . After assembly, the spline portions 166, 174 and the generally smooth portions 168 and 175 are radially aligned with and engage one another to form a rigid driving connection.

What is claimed is: 
     
         1 . A spline connection ( 160 ) comprising an internal spline connector ( 161 ) and an external spline connector ( 162 ),
 each of the spline connectors having a spline portion ( 166 ,  174 ),   at least one of the spline connectors having a substantially smooth centering portion ( 168 ) longitudinally substantially adjacent its spline portion,   the spline connectors having a first partially assembled configuration in which the spline portion ( 174 ) of one of the spline connectors is radially aligned with and engages with sliding contact the smooth centering portion ( 168 ) of the other spline connector,   the spline connectors having a second partially assembled configuration in which the spline portions of each of the spline connectors are at least partially radially aligned with one another.   
     
     
         2 . A spline connection as set forth in  claim 1 , wherein the spline connectors have a fully assembled configuration in which the entire longitudinal extent of the spline portion of the one of the spline connectors is radially aligned with at least a portion of the longitudinal extent of the spline portion of the other spline connector. 
     
     
         3 . A spline connection as set forth in any of preceding  claims 1 - 2 , wherein each of the spline connectors includes a substantially smooth generally cylindrical centering portion substantially adjacent its spline portion. 
     
     
         4 . A spline connection as set forth in  claim 3 , wherein the centering portion of the internal spline connector is on one side of its spline portion when the spline connectors are in the first and second partially assembled positions, and the centering portion of the external spline connector is on the same side of its spline portion when the spline connectors are in the first and second partially assembled positions. 
     
     
         5 . A spline connection as set forth in any of preceding  claims 3 - 4 , wherein the centering portions are only partially radially aligned and the spline portions are only partially radially aligned when the spline connection is in its second partially assembled configuration. 
     
     
         6 . A spline connection as set forth in any of preceding  claims 1 - 5 , wherein each of the spline portions is generally cylindrical. 
     
     
         7 . A spline connection as set forth in any of preceding  claims 1 - 6 , wherein the one spline connector is the internal spline connector. 
     
     
         8 . A spline connection as set forth in  claim 7 , wherein the substantially smooth centering portion of the internal spline connector guides the spline portion of the external spline connector into circumferential and longitudinal alignment with the spline portion of the internal spline connection as the spline connectors are displaced from a disassembled configuration to the first partially assembled configuration. 
     
     
         9 . A spline connection as set forth in any of preceding  claims 7 - 8 , wherein the internal spline connector has a longitudinal extent, and the spline portion of the internal spline connector has a longitudinal extent of at least about 30% of the longitudinal extent of the internal spline connector. 
     
     
         10 . A spline connection as set forth in  claim 9 , wherein the spline portion of the internal spline connector has a longitudinal extent of between about 50% and 80% of the longitudinal extent of the internal spline connector. 
     
     
         11 . A spline connection as set forth in any of preceding  claims 7 - 10 , wherein the centering portion of the internal spline connector has a longitudinal extent, and the longitudinal extent of the centering portion of the internal spline connector is at least about 10% of the longitudinal extent of the internal spline connector. 
     
     
         12 . A spline connection as set forth in  claim 11 , wherein the centering portion of the internal spline connector has a longitudinal extent of between about 20% and 60% of the longitudinal extent of the internal spline connector. 
     
     
         13 . A spline connector as set forth in any of preceding  claims 7 - 12 , wherein the other spline connector is an external spline connector having a spline portion and a generally smooth substantially cylindrical portion adjacent its spline portion. 
     
     
         14 . A spline connection as set forth in any of preceding  claims 1 - 13 , wherein the internal spline connector is on a bore ( 164 ) in a gear ( 76 ), the external spline connector is on a shaft ( 44 ), and the gear and the shaft are in a sump ( 37 ) in a hydromechanical transmission ( 11 ).