Range shift arrangement for four-wheel drive vehicles

A transfer case for a four-wheel drive motor vehicle comprising:

• a housing;
• an input shaft supported for rotation in said housing;
• an output shaft supported for rotation in said housing;
• planetary gear reduction means for selectively interconnecting said input shaft to said output shaft to define a four-wheel high-range drive mode and a four-wheel low-range drive mode;
• a shift member movable between a first position for shifting said planetary gear reduction means into said high-range mode and a second position for shifting said planetary gear reduction into said low-range mode;
• and
• synchronizer means for causing speed synchronization between said input shaft and said output shaft in response to movement of said shift member from said second position to said first position.

A planetary gear assembly comprising:

• a housing;
• a first member supported for rotation in said housing;
• a second member supported in said housing for rotation relative to said first member;
• a ring gear secured to said housing;
• a planet carrier having a plurality of planet gears supported therefrom in meshing relationship with said first member and said ring gear;
• a clutch sleeve supported for rotation with said second member and movable thereon between a high-range position wherein said clutch sleeve is engaged with said first member for transferring torque from said first member directly to said second member, and a low-range position wherein said clutch sleeve is engaged with said planet carrier for transferring torque from said first member to said second member at a reduced drive ratio;
• and
• synchronizer means for causing speed synchronization between said first and second members in response to movement of said clutch sleeve towards said high-range position.

A power transfer apparatus for a motor vehicle comprising:

• a housing;
• an input shaft supported for rotation in said housing;
• an output shaft supported in said housing for rotation relative to said input shaft;
• a planetary gear assembly coupled to said input shaft and including an output member adapted to be rotatably driven at a reduced speed ratio relative to said input shaft;
• clutch means supported for rotation with said output shaft and movable between a first position for coupling said output shaft to said output member of said planetary gear assembly for establishing a low-range drive mode for transferring drive torque from said input shaft through said planetary gear assembly to said output shaft, and a second position for coupling said output shaft to said input shaft for establishing a high-range drive mode for directly transferring drive torque to said output shaft independent from said planetary gear assembly;
• and
• synchronizer means for causing speed synchronization between said input shaft and said output shaft in response to movement of said clutch means from said first position to said second position, said synchronizer means being operable to permit the power transfer apparatus to be shifted from said low-range drive mode to said high-range drive mode without stopping rotation of said input shaft.

A two-speed power transfer apparatus for a motor vehicle of the type including a transmission having a transmission output shaft, said two-speed power transfer apparatus comprising:

• a housing;
• an input shaft supported for rotation in said housing and coupled for driven rotation with the transmission output shaft;
• an output shaft supported for rotation in said housing;
• a planetary gear assembly including a sun gear coupled for rotation within said input shaft, a ring gear fixed for non-rotation to said housing, a carrier, and a plurality of planet gears supported from said carrier, said planet gears in meshing engagement with said sun gear and said ring gear such that said carrier is driven at a reduced ratio with respect to said input shaft;
• synchronizer means for causing speed synchronization between said input shaft and said output shaft, said synchronizer means including a hub member fixed for rotation on said output shaft, a drive member coupled for rotation with said input shaft and having a first synchronizing surface formed thereon, and a blocker ring having a second synchronizing surface formed thereon which is adapted for frictional engagement with said first synchronizing surface on said drive member;
• and
• a clutch sleeve coupled for rotation with said hub member and which is axially movable thereon between a first position where a low-range drive mode is established and a second position where a high-range drive mode is established, and wherein movement of said clutch sleeve to said first position establishes a first torque path for transferring drive torque delivered to said input shaft from the transmission output shaft through said planetary gear assembly to said output shaft, and wherein movement of said clutch sleeve to said second position establishes a second torque path for transferring drive torque from said input shaft through said drive member to said output shaft.