Theory Of Operation; Traction Drive Belt System Operation; Transaxle And Shift Linkage System Operation - Sabre 1338 Gear Technical Manual

HYDROSTATIC POWER TRAIN

THEORY OF OPERATION

In this group the Sabre hydrostatic power train is
separated into the following systems:
• Traction Drive Belt System
• Transaxle and Shift Linkage System
• Brake/Neutral Return Pedal System
• Transport (Free-Wheeling) System
TRACTION DRIVE BELT SYSTEM
OPERATION
Function:
The traction drive belt transfers power from the engine
to the input pulley of the hydrostatic transaxle.
Major Components:
• Foot pedal and brake linkage
• Engine drive sheave
• Traction drive belt
• Tensioning idler assembly
• Tensioning spring
• Adjusting idler assembly
• Transaxle drive sheave
Theory of Operation:
(D) Used with
K-51 Only
D
C
The traction drive belt (A) is driven by the upper pulley
of the engine drive sheave (B). The traction belt then
transmits engine power to the input pulley of the
hydrostatic transaxle (C). On the K-51 transaxle only,
an additional idler pulley (D) is used between the
engine sheave and the transaxle. The traction drive
belt is tensioned by the tension idler (E), which is
mounted on a spring loaded bracket (F). The tension
spring (G) runs forward and hooks to the frame. When
the traction drive belt stretches beyond the range of the
spring loaded tension idler, an adjustable idler (H) can
be moved in slots on the frame, allowing the tension
idler to move back into range.
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B
A
F
G
E
H
TRANSAXLE AND SHIFT LINKAGE
SYSTEM OPERATION
Function:
The function of the transaxle is to transfer power from
the traction drive belt system (driven by the engine), to
the rear wheels, and allow the operator to select
ground speed and direction.
The drive belt turns the transaxle input pulley, and
drives the transaxle's hydrostatic pump. When the
hydrostatic drive is in neutral, no pressure is built up in
the pump. When the operator pushes the hydrostatic
drive lever forward, the shift linkage tilts the swash
plate, inside the transaxle, off center, and the pump
pistons build pressure which drives the hydrostatic
motor. The motor drives the rear axle and wheels
through the differential assembly.
The transaxle provides infinite ground speed selections
up to 5 mph in forward and up to 2.6 mph in reverse.
Major Components:
• Transaxle input pulley and fan
• Pump (input) shaft and cylinder block assembly
• Shift linkage and pump swashplate assembly
• Center block assembly
• Motor cylinder block assembly and drive shaft
• Differential assembly and axle shafts
• Wheels and tires.
Theory of Operation:
C
Neutral:
When the engine is running, the traction drive belt (A)
turns the transaxle input pulley (C), cooling fan, and
input shaft. The input shaft turns the hydrostatic pump
input shaft and pump body, inside the transaxle.
THEORY OF OPERATION
A
2/12/97