TM-9-2520-254-34 Direct Support for M113 TX100-1 Transmission 2520-00-066-4240 Download

CHAPTER 2 DESCRIPTION AND OPERATION Section I. DESCRIPTION AND OPERATION OF TRANSMISSION COMPONENTS 2-1. Torque Converter and Lockup Clutch a. Torque Converter Components (fig. 2-1). (1) The torque converter consists mainly of three cast aluminum elements: a converter pump (8), converter turbine (6), and a stator and cam assembly (7). In addition, there are other parts in the group which house and support these main elements. (2) The converter pump assembly (8) is the driving element. It rotates on a ball bearing assembly (9) supported by a converter ground sleeve (10) which is stationary and a component of the diaphragm assembly (12). The pump is bolted to a cover assembly (4) which rotates with the engine crankshaft. (3) The converter turbine assembly (6) is the driven element. It is splined to a turbine shaft (59) which transmits torque to a high-range clutch housing (16), intermediate-range sun gear (53), and a low-range sun gear (46). The turbine hub (2) is splined to a lockup clutch plate (5). (4) The stator and cam assembly (7) is the reaction element. It is mounted on an over-running clutch on a freewheel roller race (63) which is splined to a ground sleeve (10). The stator is free to rotate in the direction of engine rotation but locks up in the opposite direction. b. lockup Clutch Components (fig. 2-1). (1) The lockup clutch piston assembly (64) is a spring steel diaphragm with a clutch apply plate at its outer circumference. It is mounted on the inner hub of the converter pump cover assembly (4). and retained by a snap ring. Recesses in the piston engage the heads of the converter drive bolts, and prevent rotation of the piston relative to the pump cover. (2) The lockup clutch plate (5) is a non- metallic, internal-splined plate. It is splined to the converter turbine hub and located between the piston (64) and the lockup clutch back plate (62). (3) The lockup clutch back plate (62) is a pressed steel ring against which the plate (5) reacts when the lockup clutch is applied. Its outer diameter is held between the converter pump cover (4) and tbe pump (8) which are bolted together. c. operation of Torque Converter and Lockup Clutch (fig. 2-1). (1) The actions of the torque converter and lockup clutch are interrelated. When the lockup clutch is released, the torque converter must transmit engine power to the transmission. When the lockup clutch is engaged, there is no converter action and torque is transmitted directly from engine to transmission because the input drive components and converter turbine (6) are locked together. (2) When the lockup clutch is released, the torque converter (which is constantly filled with oil) transmits torque by hydraulic action. The blades of the pump (8) throw oil against the blades of the turbine (6), causing the turbine to rotate in the same direction as the pump. Higher pump speeds cause the oil to be thrown with more force, causing a greater rotating force in the turbine. At engine idle speed, the force of the oil, and consequently the torque transmitted, is negligible. This characteristic of hydraulic drive permits the torque converter to take the place of a friction clutch between the engine and transmission. (3) The turbine vanes direct the oil toward the center of the turbine (6), where the oil leaves the turbine in a direction opposite to pump rotation. The stator (7) redirects the flow of oil to change its direction to that of pump rotation. Unexpended energy in the oil reentering the pump (8) assists the pump. This is the key to torque multiplication. (4) Thus, the torque converter is a torque multiplier as well as a fluid coupling. Torque multiplication is highest when the turbine (6) is stalled and the pump (8) is rotating at full speed. It is lowest when the pump is rotating at its lowest speed relative to the turbine. (5) The oil, leaving the inner ends of the turbine vanes, strikes the curved vanes of the stator and is deflected into the pump vanes. It is the reaction of the oil, as it is forced to change direc- tion, which locks the stator against rotation op- posite to pump and turbine rotation. When turbine speed approaches pump speed, the oil leaving the turbine strikes the back sides of the turbine vanes and causes the stator to freewheel on the rollers (61). (6) When torque multiplication is no longer required to provide sufficient power to the vehicle drive line and vehicle speed is great enough, the lockup clutch automatically engages. In lockup operation there is no hydraulic slippage. The result is economy in operation and improvement in operating characteristics. 2-1