FI81533C - KRAFTOEVERFOERINGSSYSTEM FOER TRANSPORTANORDNING SOM GRIPER OM DUBBELHJUL. - Google Patents

Description

81533

Powertrain transmission system

The invention relates to a transmission system for a twin-wheeled transmission device for conveying an airplane or other twin-wheeled device on a platform comprising at least two friction rollers and motors rotating them, i.e. one for each wheel of the mobile device and pressed against it to provide compression, and the system includes a power unit and transmission devices 10 for supplying propulsion to the motors. Here, twin wheels also mean the adjacent wheels of the bogie.

The structure of the transfer device can be substantially lightened when the rotational force is transferred to the aircraft's own wheel from the drive wheel, i.e. the friction roller, belonging to the transfer device. A fully 15 general-purpose light transmission device structure is presented in Finnish patent application FI 833275 (partly corresponding to WO85 / 01265). This does not require any contact from the aircraft bogie to press the drive wheel against the wheel. Compression is provided by the mutual displacement of compression rollers mounted around the wheel of the aircraft and connected by an intermediate member 20.

In the most common form, the intermediate member pulls the two press rollers it binds to each other, causing them to press against the intermediate wheel. At least one of the compressible wheels is now a friction roller, i.e. a drive wheel, which transmits the rotational force to the wheel of the aircraft 25. Other transmission devices within the scope of the invention are disclosed in Finnish patent applications FI861714, FI870313 and FI870710. Virtually all aircraft are equipped with either twin wheels or larger bogies. It is thus natural to form the transfer device for gripping the twin wheels, since then the maximum load on the tire can be reduced. Conveyors with so-called self-wedge friction rollers are not advantageous in this respect, since they load the wheel of the aircraft considerably more than the conveyor gripping each wheel with two or more friction rollers. In any case, the present invention is also applicable, for example, in the transfer device according to the above-mentioned application FI870710, which discloses a self-wedge transfer device adhering to twin wheels, in which both friction rollers are equipped with their own motor and gearbox.

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A transfer device that engages a twin wheel, especially a gear wheel, is disclosed in U.S. Patent No. 3,005,510. Here, adjacent bogie wheels are driven by two friction tracks that are wedged between successive bogie wheels. The hydraulic power transmission 5 includes, as well as directing nvaihtoven11ii i 1 that the flow divider valve, by means of which the right and left sides of h y d r a z o 1 imoo 11 r e i 11, e reaching the flow can be adjusted. The adjustment takes place by means of two interconnected throttling points, whereby when one is reduced, the other increases. This provides 10 nokkatelipyörästö turn throttling the second side of the hydraulic-1 im No o11orei 11e degree of the flow while the other side of the throttling is reduced.

This invention relates in particular to transfer devices in which transfer takes place only from another main landing line. This is new in itself, because according to the prior art, the push has always been symmetrical. The asymmetrical push causes a turning force on the machine, which is not normally a problem, as the cam pulleys of the machine are still able to steer the machine in the desired direction. Problems may occur under certain special conditions. In winter conditions, the icy and snowy field is completely different from the summer dry asphalt surface in terms of friction conditions. In addition, a strong crosswind increases the turning force of the machine. Practical tests have found it particularly difficult - conditions in which an empty machine had to be moved well in 25 snow-guided fields. One ring of a pair of wheels may rise alone to carry, allowing the other to rotate freely. Another phenomenon of the same type occurs on an icy field when one of the rotatable wheels begins to slip against the ice. All the hydraulics connected to the same circuit 30 lose their supply pressure because the flow leaks through the motors rotating the slippery wheel. Another serious disturbance is caused if the camshafts start to slip sideways, r. The rotation then takes place around the landing • stand next to the push-down landing gear, which therefore remains in place.

V. 35 The object of the present invention is to provide a transmission system for a transmission device rotating twin wheels, which provides a stable thrust, even if the position of the thrust point is used as a head step, which is disadvantageously on the side of the center line. The features of the invention are clear from the appended claim 1 of the claimed patent. The main principle of the invention is to synchronize the use of different motors and corresponding friction rollers. This mainly means locking the friction rollers in the same phase and at the same speed. If the other wheel can slip to the ground, the adjacent wheel will continue to pull. This same locking also limits the side slip of the camshaft, because then the adjacent wheels have to rotate at different speeds.

The embodiment according to claim 2 is the simplest solution for providing a locking of the hydraulic transmission. The manifolds must be pressure compensated to prevent the flow from escaping through the freely rotating motor. A more reliable locking function 1 is achieved by implementing the system according to claim 3, wherein the synchronization of the motors implemented with practical components is considerably more accurate than before. The turning of the movable device during the transfer is made possible by implementing the system according to claim A. This is particularly necessary in the case of a transfer device with two pumps and completely separate circuits, but is also useful in the case of separate hydraulic circuits provided by flow distribution doors. The invention is also applicable when using electric power transmission. The electric motor control is preferably based on frequency converter technology and the whole system can be based on diesel electric transmission.

The embodiment according to claim 7 also enables a new method for reversing the torque caused by a one-sided push. In addition to the thrust, the transfer device generates a torque that cancels out, in whole or in part, the turning force caused by the thrust. The brake device 30 is formed in a hydraulic system with two pumps simply by setting the pumps asynchronous, i.e. the output of one pump is set lower than that of the other.

In the following, the invention will be illustrated by means of Examples 35 with reference to the accompanying figures, which show some embodiments of the invention.

Figure 1 shows the use of the transfer device in moving the aircraft Figure 2 shows the transfer device in the operating position seen from above 4 81 533

Figure 3 shows a schematic diagram of the hydraulic transmission system of the transmission device according to Figure 2. Figure 4 shows a cross-section of a flow distribution valve. Figure 5 shows a schematic diagram of another hydraulic transmission system.

In the situation shown in Fig. 1, the transfer device 20 pushes the aircraft 1 from the right main landing gear 21 with a twin wheel. The push causes a torque to turn the machine around the left landing gear 10, which is canceled by the lateral frictional force of the machine cam 22. Fig. 1 shows an arrow describing the thrust of the transfer device and, in broken lines, the counter-torque generated by the transfer device in one embodiment, which cancels the turning force of the machine. Normally no counter-torque is generated, but this is necessary especially on slippery ground. During the transfer, the aircraft 1 is controlled by turning the cam wheel 22 in the desired direction.

Figure 2 shows only a part of the landing gear and the wheels 6 of the aircraft 1. The transfer device rests on its wheels and its main parts are friction rollers 3 and 4, these are driven by hydraulic motors 5 with gearboxes and a power unit including a hydraulic pump unit driven by a diesel engine.

Both wheels 6 have their own friction rollers 3 and 4, each of which is driven by a hydraulic motor 5. The front friction rollers 4 are arranged to turn sideways in a known manner so that the transfer device can drive the wheels 6 around the aircraft 1. The support of the front friction rollers 4 is arranged by means of a sliding member 7, which is moved by means of a hydraulic blade 2 and which can also turn in its extreme position. Figure 2 shows the same driving phase as in Figure 1.

The main components of the hydraulic transmission system of Figure 3 are the pump unit · driven by the diesel engine 8, the hydraulic motors 5 and the pressure compensated flow distribution valves 10. t5 The pump unit comprises a high pressure pump 9 and its supply pump and a leak oil system. The reversal and the change of the transmission are performed by changing the stroke1a of the high pressure pump 8 and changing the flow direction. By means of the flow distribution valves 10, the motors 5 are divided into two groups. The second group

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81 533 5 ta and one on the left wheel 6. The flow distribution valves 10 actually operate only in the other direction, in the return direction they allow free flow. For this reason, they are needed for two, i.e. for each flow direction, their own. Figure 4 shows the structure of the pressure compensated flow distribution valve 10 in detail. The pipe coming from the pump 9 is connected to the joint 11 and the pipes leading to the motors 5 to the joint 12. In Fig. 4, the main flow directions are indicated by arrows. The pressure compensation is arranged by a movable spindle 13. The return flow 10 takes place almost without hindrance through the valves 14. In the system of Figure 3, the second constant flow valve 10 precisely divides the flow into two parts and the other collects the flows to the pump 9.

More accurate synchronization is achieved with the two-pump system of Figure 5. Here, each of the above-mentioned 15 motor groups is driven by its own pump 15. In these, the rotational speed is the same and the control levers are connected to turn synchronously in the normal situation. Under good conditions, the valve 19 is kept open, so there is no locking between the right and left wheels. When the field is icy or in windy weather 20, the valve 19 is closed, whereby the synchronous operation of the motors 5 tends to keep the machine in a straight line. By setting the above-mentioned control levers of the pumps 15 to a different position, one starts to produce more than the other. In the lower flow circuit, the motors 5 start to brake. If the braking circuit 25 is connected to the right-hand wheel 6 in the situation of Fig. 1, i.e. in the situation of the right-hand pushing transfer device, the transfer device 20 produces a pushing force which produces a torque canceling torque. Such torque cancellation is necessary, for example, when moving a relatively long type of aircraft in an icy field 30 and in windy weather.

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Claims (7)

1. A power transmission system for a displacement device such as gripper in pairs of wheels, wherein the displacement device is intended to move aircraft (1) or another pair of wheels fitted on a ground, where the displacement device includes rainst two friction rollers (3, 4) and motors (3). 5) rotating around them, ie one for each wheel (6) of the device (1) is to be moved and the friction roller (3, 4) is to be pressed against it, pressing means (2) for receiving each other pressing, and to the sister there is a power source (8) and power transmission means for releasing the power to the motors, characterized in that the system includes means (10) for releasing the power separately and substantially independently of each other of the motors (5) each of the wheels (6). A hydraulic power transmission system for a displacement device according to claim 1, to which belongs a pump (9), which drives said hydraulic motors (5), characterized in that the toil sister comprises at least one pressure-compensated distribution valve (10) which divides it by the purape (9) feeds the fluid volume in two parts, to drive separately around each wheel (6) so that the operation of the corresponding hydraulic rotors (5) is not substantially dependent on the other, i.e. the corresponding load of the adjacent wheel (6) of the engine (5). A hydraulic power transmission system for a moving device according to claim 1, characterized in that the tile sister belongs to two separate power sources, e.g. a diesel engine 30 (8), synchronously coupled pairs (15), one of which drives the motors (5) rotating the left wheel (6) and the other corresponding motors (5) driving the right wheel (6). 1 A hydraulic power transmission system for a moving device according to claim 2 or 3, characterized in that the system includes conduits (18), provided with red valves (19) which connect the pressure and return sides of the various hydraulic circuits (16, 17). 9 81533 An electrical power transmission system for a moving device according to claim 1, characterized in that the system belongs to a power source, e.g. accumulator, and at least two motors provide sprinklers for their operation. A power transmission system for a displacement device according to claim 2, 3, 4 or 5, wherein the displacement device belongs, for each wheel. (6) to be rotated, at least 10 pressure wheels to be arranged on opposite sides thereof and pressed against it, of which at least one, heist, all are friction rollers (3, 4) rotating the wheel (6), characterized in that the motors (5) are arranged in two groups with respect to the feed of the driving force, where one group rotates one or more wheels (6) on the left side and the other group corresponding wheels (6) on the right side. A power transmission system for a displacement device according to claims 1-6, wherein the displacement device is intended to slide on aircraft precisely on the par or bogie wheels of the main landing gear, characterized in that the system includes devices for braking at least one pair of wheels at least one outer wheel at the same time. one inner wheel drive. 25