GEAR 1397810 - Caterpillar

Illustration 1 g06098496
Final Drive Cross Section
(1) Housing
(2) Hub
(3) Power out
(4) Brake passage
(5) Brake coupling
(6) Power from motor
(7) Brake springs
(8) Brake piston
(9) Brake piston chamber
(10) Disks and plates
(11) Ring gear
(12) First-stage planet gears
(13) First-stage planet carrier
(14) First-stage sun gear
(15) Second-stage sun gear
(16) Second-stage planet carrier
(17) Second-stage planet gearsEach propulsion motor drives a track through a single-speed planetary final drive. The right and left final drive assemblies are identical. The final drive assembly contains a parking brake and two planetary gear assemblies. The planetary gear assemblies share ring gear (11), which is part of hub (2).Components inside the planetary final drive are splash lubricated. The housing serves as the oil reservoir.The parking brakes are spring applied and hydraulically released. These wet brakes are engaged through the compression of a series of disks and plates (10). The disks are splined to brake coupling (5). The plates are splined to housing (1). The brake plates and disks are splash lubricated.Charge oil from the propulsion pump is used to release the parking brakes. When the brakes are engaged, the brake valve opens brake passage (4) to the hydraulic tank. Brake springs (7) move brake piston (8) against brake disks and plates (10). This action compresses the disks and plates, so brake coupling (5) cannot rotate.When the brakes are released, charge pressure is directed into brake piston chamber (9). Charge pressure acts against brake piston (8). This action opposes brake springs (7). The charge pressure overcomes the spring force, and the brake piston moves. This movement releases the compressive force on disks and plates (10).When the machine is moving, the output shaft of the propulsion motor turns first-stage sun gear (14). In the first-stage planetary, ring gear (11) is part of the hub, and planet carrier (13) is splined to second-stage sun gear (15). Therefore, rotation of the first-stage sun gear causes the second-stage sun gear to rotate.In the second-stage planetary, sun gear (15) is driven. Second-stage planet carrier (16) is part of housing (1), and therefore, is held. Under these conditions, second-stage planet gears (17) cause ring gear (11) to rotate. The ring gear is connected to hub (2). Hub transfers power out (3) to the track.