jcb JS 200 Series, Service Manual

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3 - 8
Section F
Transmission
9803/6400
Section F
3 - 8
Issue 1
Motor/Gearbox
Operation (continued)
2-Speed Switch Mechanism
2-Speed Switch Mechanism Assembly
The swash plate has three surfaces,
A, B and C as illustrated in Fig. 7, being assembled in a slantable state in the motor case
with two steel balls.
The 2-speed switch valve is assembled inside the base plate.
Fig. 7 2-Speed Mechanism Assembly
The following instructions refer to the illustrations following this section.
2-Speed Mechanism
Refer to Fig. 8-2
When the 2-speed mechanism is in the position as illustrated, the motor driving pressure works on the 2-speed control piston.
The swash plate is slanted to the position where the resultant thrust force of the piston sub-assembly and the spring force are
balanced with the thrust force of the 2-speed control piston. The swash plate settles when surface
B comes into contact with
the motor case and the motor is then in second, or high speed.
Refer to Fig. 8-1
When the 2-speed valve is in the position as illustrated, the 2-speed control piston cavity is connected to the motor case drain
and the swash plate is pushed by the resultant force of the piston sub-assembly thrust force and spring force. The swash plate
settles when surface
A comes into contact with the motor case and the motor is in first or low speed.
When the engine stops, the swash plate is pressed by spring force to bring the surface A into contact with the motor case. The
motor changes into first, or low speed.
C
A
B