PISTON 1404015 - Caterpillar

Illustration 1 g06059086
Final Drive Cross Section
(1) Hub
(2) Power out
(3) Power from motor
(4) Third-stage planet gears
(5) Third-stage planet carrier
(6) Second-stage ring gear
(7) Second-stage planet gears
(8) Second-stage planet carrier
(9) First-stage ring gear
(10) First-stage planet gears
(11) First-stage planet carrier
(12) First-stage sun gear
(13) Second-stage sun gear
(14) Third-stage sun gear
(15) Third-stage ring gear
(16) Disks and plates
(17) Brake piston chamber
(18) Brake piston
(19) Brake passage
(20) Brake springs
(21) Brake couplingEach propulsion motor drives a wheel 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 three planetary gear assemblies.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 (16). The disks are splined to brake coupling (21). The plates are splined to the housing. The brake plates and disks are splash lubricated.Oil from the auxiliary hydraulic pump is used to release the parking brakes. When the brakes are engaged, the brake solenoid opens brake passage (19) to the hydraulic tank. Brake springs (20) move brake piston (18) against brake disks and plates (16). This action compresses the disks and plates, so brake coupling (21) cannot rotate.When the brakes are released, auxiliary pressure is directed into brake piston chamber (17). Auxiliary pressure acts against brake piston (18). This action is in opposition to brake springs (20). The auxiliary pressure overcomes the spring force, and the brake piston moves. This movement releases the compressive force on the disks and on plates (16).When the machine is moving, the output shaft of the propulsion motor turns first-stage sun gear (12). In the first-stage planetary, ring gear (9) is fixed to the hub, and planet carrier (11) is splined to the second-stage sun gear (13). Therefore, rotation of the first-stage sun gear causes the second-stage sun gear to rotate.In the second-stage planetary, sun gear (13) is driven and ring gear (6) is held. Therefore, interaction between the second-stage sun gear and second-stage planet gears (7) cause the second-stage planet carrier (8) to rotate. The second-stage planet carrier is connected to third-stage sun gear (14).In the third-stage planetary, sun gear (14) is driven and planet carrier (5) is held. Under these conditions, planet gears (4) cause third-stage ring gear (15) to rotate. The third-stage ring gear is connected to hub (1). Hub transfers power out (2) to the wheel.