WHEEL PAIR FOR A TRANSPORT DEVICE

Abstract: The proposed wheel pair for a transport device comprises the wheels (2), which are rigidly mounted on an axle (1) and have hubs (3) and rims (4); the inner surface of the rim (4) and the surface of the hub (3) in contact with it, at least in one of the wheels (2), take the form of cylindrical or conical surfaces of rotation (5).

Description: Sector of the art The invention relates to transport mechanical engineering, more specifically to wheel sets of transport devices. The prior art Widely-known wheel sets comprise an axle and wheels, the hubs of which are rigidly connected to the axle whereas the running surfaces are formed on rims rigidly connected to the hubs. When the known wheel set is used, the wheels cannot move at different angular speeds, and this results in increased wear on the running surfaces of the wheels and the rails and also increases the consumption of energy. There is also a known set with a friction slip limiter, wherein one wheel is rigidly connected to the axle whereas the other is connected to the axle via bushes and a front friction clutch adjusted to a limiting torque. (SU, No. 1782776, Int. Cl. B60B 39/14). In this wheel set, owing to the constant compressive force of the front friction clutch, there is low efficiency in equalising the angular speeds of the wheels, and the wheel set operates only on a rail track with a very small radius of curvature, which limits its range of usefulness. In addition, the wheel set has a complicated construction and is complicated in use. The wheel set nearest in technical nature to the applied-for invention comprises an axle and wheels having their hubs rigidly connected to the axle whereas the running surfaces are formed on rims, one of which is rigidly connected to the hub whereas the other is connected thereto with possibility of rotation. The features of the preamble of claim 1 are known from DE-A-3 740 140. The distinguishing feature of this wheel set is that the rim is connected to the hub via worm gears and control drives, fitted in the wheel. This greatly increases the complexity of the construction of the set, owing to the need for a system of control of drives, connected to transducers disposed along the track of the transport device. Outline of the invention The invention is based on the problem of constructing a wheel set for a transport device wherein the connecting unit between the hub and the rim is changed so as automatically to reduce the resistance to motion of the transport device and simultaneously simplify the construction of the wheels and increase the reliability of the wheel set, and also reduce the wear on the running surfaces of the wheels and the rail. To this end, in the wheel set of a transport device according to the invention, the inner surface of the rim and the surface in contact therewith are in the form of surfaces of rotation, and the parameters of the rim and the hub are chosen such that the torque defined by the frictional forces in the zone of contact between the surfaces is very near the torque applied to a wheel of the set when it moves from its position and travels. The shape of the surfaces in contact, i.e. two surfaces of rotation, increases the coefficient of friction compared with the coefficient of friction between the wheel and the rail. In addition, contact along the surfaces of rotation enables the inevitable slip to be transferred from the area of contact between the wheel and rail to the internal zone of the wheel, which can be made of wear-resistant material and with set friction parameters. Brief description of the drawings The invention will now be disclosed in detail in a description with reference to the accompanying drawings, in which: Fig. 1 is a view in section of the proposed wheel, in one variant embodiment, and Fig. 2 is the same as Fig. 1, showing another embodiment of the proposed wheel. The best embodiment of the invention A wheel set comprises an axle 1 (Fig. 1) and wheels 2 (one wheel of the set is shown in Figs. 1 and 2). The hub 3 of each wheel 2 is rigidly connected to the axle 1, and the rim of one wheel 2 is connected to the hub 3 with possibility of rotation, and the inner surface of the rim 4 and the surface of the hub 3 in contact therewith are in the form of surfaces 5 of rotation, e.g. cylindrical as shown in Fig. 1. The parameters of the surfaces 5, i.e. the diameter, roughness, hardness and the materials of the rim and hub, are chosen so that the torque defined by the forces of friction in the contact zone "a" between the said surfaces 5 of the rim 4 and the hub 3 is very near or equal to the torque applied to the wheel 2 of the set when it moves off and travels. The rim 4 is formed with a running surface 6 adapted to interact with a rail 7. The hub 3 has end surfaces 8 for preventing the rim 4 for flying off. Fig. 2 shows a wheel of a set having conical surfaces 5 of rotation. In one example of a wheel set, the radius of the surfaces 5 of rotation is greater than half the radius of the running surface 6 of the wheel, the coefficient of friction varies from 0.1 to 0.3, the surfaces in contact of the wheels are made from wear-resistant materials used in all friction drives, and lubricant can be used. The end surfaces 8 are made of anti-friction material with use of lubricant. The wheel set operates as follows. When the transport device begins to move, the drive begins to rotate the axle 1 of the wheel set, together with the hub 3 of the wheel 2 and the rim 4. Since the torque between the surfaces 5 of the rim 4 and the hub 3, under the action of the weight of the transport device, at that moment is greater than or equal to the torque transmitted by the drive to the axle 1, the rim 4 will rotate together with the hub 3 like a single whole and the transport device will begin to move as if on wheel pairs with rims rigidly connected to the hubs. As the speed increases, the wheel pair will be able to drive the running surfaces 6 of the wheels 2 in rotation at different angular speeds. During travel round bends on the track, the rim 4 rotates relative to the hub 3 and compensates the difference in the angular speed of the wheels. If the diameters of the rims 4 of the wheel set are different, the effect will be the same. The result is significantly to reduce the wear on the wheels of the transport device and the rails and also to reduce losses of energy, owing to the reduction in the resistance to the motion of the transport device. The embodiment of the invention described hereinbefore does not exclude the possible use of other variant embodiments, without departing from the scope of the claims. Industrial application The wheel set is most successfully used in railway transport.

Claims: A wheel set for a transport device, which wheel set comprises an axle (1) and two wheels (2), wherein each of said wheels comprises a hub (3) that is rigidly connected to the axle and a rim (4), and wherein the rim (4) of at least one of the wheels (2) is rotatably connected to the hub and has a running surface (6) formed thereon for engaging a rail of a track; characterised in that an inner surface of the rim bears on an outer surface of the hub, which inner and outer surfaces are provided in the form of surfaces of rotation, and the diameter, roughness, hardness and materials of the rim and hub are selected such that, in use, the moment of limiting friction between the rim and hub is approximately equal to the torque applied to the wheel by a transport device when it starts off and travels. A wheel set as claimed in claim 1, characterised in that said rim (4) and hub(3) have frusto-conical surfaces of rotation. A wheel set as claimed in claim 1 or claim 2, characterised in that said hub (3) comprises at least one flange for retaining the rim (4) on the hub. A wheel set as claimed in claim 3, characterised in that said flange includes an end surface (8) made of anti-friction material with use of lubricant. A wheel set as claimed in any preceding claim, characterised in that the radii of the surfaces of rotation are greater than half the radius of the running surface (6) of the rim (4). A wheel set as claimed in any preceding claim, characterised in that the coefficient of friction of the surfaces of rotation is in the range 0.1 to 0.3. A wheel set as claimed in any preceding claim, characterised in that the surfaces of rotation are made of wear resistant material. A transport device comprising at least one wheel set as claimed in any of claims 1 to 7.

Inventors: FRIDBERG ARKADY MOISEEVICH, VINNIK LEONID VLADIMIROVICH, FRIDBERG, ARKADY MOISEEVICH, VINNIK, LEONID VLADIMIROVICH
Applicants: FRIDBERG ARKADY MOISEEVICH, VINNIK LEONID VLADIMIROVICH, FRIDBERG, ARKADY MOISEEVICH, VINNIK, LEONID VLADIMIROVICH
Application year: 1995
Main classification: B60B37
IPC codes: B60B37, B60B17