Steering Arrangement
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| Illustration 1 | g00737628 |
(1) Front axle (2) Front steering cylinder (3) Tie rod (4) Steering case (5) Pivot pin (6) Rear steering cylinder (7) Rear axle | |
Front axle (1) and rear axle (7) have similar steering arrangements. Front steering cylinder (2) and rear steering cylinder (6) are an integral part of each axle housing. Each cylinder is equipped with two tie rods (3). Each tie rod is mounted to steering case (4) at each wheel. When the steering wheel is being turned, hydraulic oil forces steering cylinders to move tie rods (3). The tie rods act on steering cases (4). The steering cases rotate on pivot pins (5) at each wheel. This action allows the wheels to turn in the desired direction.
Note: The steering mode and the direction of the rotation of the steering wheel will determine the direction of movement of the wheels.
Steering Modes
The machine may be operated in three different steering modes:
- Two-wheel steer
- Circle steer
- Crab steer
Two-wheel steer - When the machine is operated in two-wheel steer, the front wheels are the only active steering wheels. The rear wheels must be in a straight ahead position for proper operation of two-wheel steer. This mode is the only acceptable mode for roading the machine.
Circle steer - All wheels are steered in this mode. The rear wheels are steered in the opposite direction to the front wheels. This mode provides a shorter turning radius for turns in tight areas.
Crab steer - All wheels are steered in this mode. The rear wheels are steered in the same direction as the front wheels. This mode enables the machine to move in a sideways manner for maneuverability in confined areas.
There are two different arrangements for the steering modes. Some machines are equipped with a self-aligning feature for the rear wheels. This feature helps to align the rear wheels in a straight ahead position. The alignment of the rear wheels is necessary in order to properly operate the machine in two-wheel steer. In addition, the rear wheels must be aligned when you switch modes from crab steer to circle steer and from circle steer to crab steer. On machines that do not have the self-aligning feature, the rear wheels must be manually aligned.
Machines Without Self-Aligning Rear Steering
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| Illustration 2 | g00737666 |
(8) Mode select switch | |
| Mode select switch (8) - This switch is a three-position switch that controls the steering mode. The mode select switch is found on machines that are not equipped with self-aligning rear steering. This switch allows the machine to travel in two-wheel steer, in crab steer, or in circle steer. |
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| Illustration 3 | g00737668 |
(9) Indicator for circle steer (10) Indicator for crab steer | |
When the top of mode select switch (8) is depressed, the contacts for crab steer close. Power is sent to the solenoid for crab steer which is mounted on the selector valve. The energized solenoid shifts the spool in order to allow oil flow to the rear steering cylinder for crab steer. Indicator light (10) for crab steer will illuminate when this mode is selected.
When the switch is in the center position, the contacts are open and the solenoids on the selector valve will not be energized. This will allow the machine to operate in two-wheel steer.
When the bottom of the switch is depressed, the contacts for circle steer close. Power is sent to the solenoid for circle steer which is mounted on the selector valve. The energized solenoid shifts the spool in order to allow oil flow to the rear steer cylinder for circle steer. Indicator light (9) for circle steer will illuminate when this mode is selected.
Refer to the Operation and Maintenance Manual, SEBU7371, "Steering Mode Control" for additional information on the switches.
Machines With Self-Aligning Rear Steering
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| Illustration 4 | g00737715 |
| Master steering select switch (11) - This three-position switch is used in conjunction with the mode select switch. The switch is installed on machines that are equipped with self-aligning rear steering. When the top of the switch ("2") is depressed, the self-aligning function is selected. When the switch is in the center position ("padlock"), two-wheel steer is selected. When the bottom of the switch ("4") is depressed, four-wheel steer is selected. |
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| Illustration 5 | g00737712 |
| Mode select switch (12) - This switch controls the steering mode in conjunction with the master steering select switch. The mode select switch is installed only on machines which are equipped with self-aligning rear steering. This switch determines whether the machine will operate in crab steer or in circle steer. When the top of the switch is depressed, crab steer is the selected mode. When the bottom of the switch is depressed, circle steer is the selected mode. |
On machines that are equipped with the self-aligning rear steering, master steering select switch (11) and mode select switch (12) are used to control the steering mode. The two switches work in conjunction with each other in order to select the desired mode.