| |
| Illustration 1 | g00916538 |
|
View of D6N differential steering system from the rear of the tractor (1) Steering motor (2) Transfer gears (3) Pinion gear (4) Bevel gear (5) Outer axle shaft (6) Final drive (7) Planetary and brake (8) Inner axle shaft (9) Bevel gear shaft (10) Steering differential (11) Outer axle shaft (12) Final drive | |
The machine uses a differential steering system. The basic system includes a steering differential (10), a hydraulic pump, a steering motor (1), and steering controls.
Steering differential (10) receives power from two components. One power input is from the transmission for control of the speed and for FORWARD or REVERSE movement. The other input is from the hydraulic motor for control of the steering.
Steering motor (1) turns steering differential (10). The steering differential increases the speed of one track. The steering differential decreases the speed of the other track. The speed difference of the tracks turns the machine.
The direction of rotation of steering motor (1) determines the direction of the turn. A higher motor speed results in a sharper turn of the machine.
| |
| Illustration 2 | g01898873 |
|
(3) Pinion gear
(4) Bevel gear (4A) Bevel gear set (5) Outer axle shaft (7) Planetary gear train (8) Inner axle shaft (9) Bevel gear shaft (10) Steering differential (11) Outer axle shaft (13) Carrier (14) Planetary gears (15) Pinion gear for steering differential (16) Ring gear (17) Carrier (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (22) Planetary gears (23) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear | |
Transmission power flow is introduced through pinion gear (3) and bevel gear (4). The power flow is modified by the power flow from the steering motor which flows through pinion gear (15) and bevel gear (25).
Steering differential (10) includes two planetary gear trains, a bevel gear set, and a set of brakes. The following components are mechanically connected with the steering differential: bevel gear set (4A) of the transmission, planetary gear train (7) and the brakes.
The planetary gears, the bevel gears, and the brakes are connected by components in the power train. Two outer axle shafts, an inner axle shaft, and the bevel gear shaft of the transmission connect these components of the power train. Power is transmitted from the steering differential and the right side equalizing planetary, through the outer axle shafts, and to the final drives.
Pinion gear (3) and bevel gear (4) are connected to carrier (17) by bevel gear shaft (9). Pinion gear (15) and bevel gear (25) are connected to housing (26).
Ring gear (27) is connected to housing (26). Planetary gears (14) connect ring gear (27) to carrier (13). Outer axle shaft (11) connects to carrier (13). Ring gear (16) connects carrier (13) and carrier (17) through planetary gears (22).
Sun gears (24), (23), and (21) are connected to inner axle shaft (8). Outer axle shaft (5) is connected to carrier (19). Stationary ring gear (18) is connected to the brake housing, which is connected to the bevel gear case. The outer axle shafts are connected to the final drives that turn the tracks.
Power flow through the differential steering system comes from the following sources:
- Transmission
- Steering
- Combined Transmission and Steering
| |
| Illustration 3 | g01898853 |
|
Power flow schematic of the differential steering system with straight forward movement of the machine (3) Pinion gear (4) Bevel gear (5) Outer axle shaft (8) Inner axle shaft (9) Bevel gear shaft (11) Outer axle shaft (13) Carrier (14) Planetary gears (15) Pinion gear for steering differential (16) Ring gear (17) Carrier (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (22) Planetary gears (23) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear | |
In the steering differential, pinion gear (15) and bevel gear (25) are in the HOLD position. Power from the transmission is transferred through pinion gear (3) to bevel gear (4). Bevel gear (4) sends the power through bevel gear shaft (9) to carrier (17). Power through carrier (17) is sent in two directions. Most of the power is sent through planetary gears (22) to ring gear (16). The rest of the power is transferred through planetary gears (22) to sun gear (23).
Ring gear (16) sends the power through carrier (13) to outer axle shaft (11). Sun gears (23) send the power through inner axle shaft (8) to sun gear (21). Sun gear (21), planetary gears (20), carrier (19), and stationary ring gear (18) multiply the power. These power train components send the power to outer axle shaft (5).
The power to both axles is equal. Both axles have the same direction of rotation. The machine moves straight ahead.
| |
| Illustration 4 | g01897634 |
|
Rotation of the components during straight forward movement of the machine (1) Steering motor (2) Transfer gears (3) Pinion gear (4) Bevel gear (5) Outer axle shaft (8) Inner axle shaft (9) Bevel gear shaft (11) Outer axle shaft (13) Carrier (14) Planetary gears (not shown) (16) Ring gear (17) Carrier (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (22) Planetary gears (23) Sun gear (24) Sun gear (27) Ring gear (28) Final drive sun gear (29) Final drive sun gear | |
| |
| Illustration 5 | g01898814 |
|
Power flow during a sharp left turn of the machine (5) Outer axle shaft (8) Inner axle shaft (11) Outer axle shaft (13) Carrier (14) Planetary gears (15) Pinion gear for steering differential (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear | |
The transmission is in the NEUTRAL position. Power from the steering motor is sent through pinion gear (15) to bevel gear (25). Bevel gear (25) sends the power through housing (26), through ring gear (27), and through planetary gears (14) to carrier (13). Power through carrier (13) is sent in two directions.
Half of the power is transferred through planetary gears (14) to sun gear (24). The rest of the power is sent to outer axle shaft (11). Sun gear (24) sends the power through inner axle shaft (8) to sun gear (21). Sun gear (21), planetary gears (20), carrier (19), and stationary ring gear (18) multiply the power. These power train components send the power to outer axle shaft (5).
The power to both axles is equal. The axles have the opposite direction of rotation. The machine rotates counterclockwise.
| |
| Illustration 6 | g00916540 |
|
Rotation of the components during a sharp left turn (transmission in NEUTRAL) (1) Steering motor (5) Outer axle shaft (8) Inner axle shaft (11) Outer axle shaft (13) Carrier (14) Planetary gears (not shown) (15) Pinion gear (16) Ring gear (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (22) Planetary gears (23) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear (28) Final drive sun gear (29) Final drive sun gear | |
Combined Transmission and Steering Power Flow
| |
| Illustration 7 | g01897638 |
|
Power flow schematic of the differential steering system for a gradual left turn (3) Pinion gear (5) Outer axle shaft (8) Inner axle shaft (11) Outer axle shaft (13) Carrier (15) Pinion gear for steering differential (16) Ring gear (18) Stationary ring gear (19) Carrier (21) Sun gear (23) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear (A) Direction of power flow for speed (B) Direction of power flow for steering (C) Direction of combined power flow | |
Power from the steering motor and from the transmission can act together on the differential steering system. The power input from the transmission flows through the system normally. The power input from the steering motor is transferred through the system to one outer axle.
The power to one axle is greater. The speed of that axle shaft increases. The other axle decreases speed.
The amount of power to the axle shafts is controlled by the transmission. The speed of rotation of the axle shafts is controlled by the transmission.
The difference in speed between the axle shafts is controlled by the steering motor. The rotation of the steering motor and of pinion gear (15) controls the direction of turn. Refer to Table 1.
The speed of the steering motor and of pinion gear (15) determines the rate of turn. A faster steering motor speed produces a sharper turn.
| Left Turn in Forward | Left Turn in Reverse | Right Turn in Forward | Right Turn in Reverse | |
| Rotation of the Steering Motor and Pinion Gear (3)(1) | Clockwise | Counterclockwise | Counterclockwise | Clockwise |
| Rotation of Pinion Gear (25) from the Transmission | Clockwise | Counterclockwise | Clockwise | Counterclockwise |
| Position of the Tiller | Forward | Back | Back | Forward |
| (1) | The observed rotation from the drive end of the shaft |
| |
| Illustration 8 | g00916541 |
|
Rotation of the components during a gradual left turn and during forward movement (1) Steering motor (2) Transfer gears (3) Pinion gear (4) Bevel gear (5) Outer axle shaft (8) Inner axle shaft (9) Bevel gear shaft (11) Outer axle shaft (13) Carrier (14) Planetary gears (not shown) (15) Pinion gear (16) Ring gear (18) Stationary ring gear (19) Carrier (20) Planetary gears (21) Sun gear (22) Planetary gears (23) Sun gear (24) Sun gear (25) Bevel gear (26) Housing (27) Ring gear (28) Final drive sun gear (29) Final drive sun gear | |
The machine turns gradually to the left.
Pinion gear (15) for steering and pinion gear (3) for speed rotate in the same direction. Power to pinion gear (15) is transferred through bevel gear (25) and through housing (26) to ring gear (27). Ring gear (27) sends the power through the planetary gears to sun gear (24). Sun gear (24) sends the power to inner axle shaft (8) (center axle shaft). This power adds to the power to sun gear (23).
The combined power through inner axle shaft (8) is transferred to sun gear (21). Sun gear (21), planetary gears (20), carrier (19), and stationary ring gear (18) multiply the power. This power is sent to outer axle shaft (5).
Outer axle shaft (5) increases speed. Outer axle shaft (11) decreases speed proportionally.
The power to sun gear (24) adds to the power to sun gear (23). The increase in power increases the speed of the sun gears. When the speed of sun gear (23) increases, the speed of ring gear (16) decreases. The decrease in speed of ring gear (16) decreases the speed of carrier (13). The speed of outer axle shaft (11) decreases.
Outer axle shaft (5) is turning faster. Due to the speed difference, the machine turns left.
The machine turns gradually to the right.
Pinion gear (15) for steering and pinion gear (3) for speed rotate in opposite directions. Power to pinion gear (15) is transferred through bevel gear (25) and through housing (26) to ring gear (27). Ring gear (27) sends the power through the planetary gears to carrier (13). This power adds to the power through ring gear (16) to the carrier.
The combined power is transferred through carrier (13) to outer axle shaft (11).
Carrier (13), ring gear (16), and outer axle shaft (11) increase speed. When the speed of ring gear (16) increases, the speed of sun gear (23) decreases.
When sun gear (23) decreases speed, inner axle shaft (8), sun gear (21), carrier (19), and outer axle shaft (5) decrease speed.
Outer axle shaft (11) is turning faster. Due to the speed difference, the machine turns right.