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Title:
METHOD AND APPARATUS FOR STEERING A ROADWAY VEHICLE TRAIN
Document Type and Number:
WIPO Patent Application WO/2016/166561
Kind Code:
A1
Abstract:
This invention relates to a method and apparatus for steering a roadway vehicle train having at least two vehicle bodies (K1, K2...Kn-1, Kn), a bogie (F1-Fm) linking two adjacent vehicle bodies (K1, K2...Kn) and a stiff-axle wheel assembly (T1-Tm) pivoted on the bogie (F1-Fm) assigned to a respective vehicle body (K1, K2...Kn-1, Kn). The method comprising steering the first-in-the-course stiff-axle wheel assembly (T1) by an angular rotation opposite to the angular rotation of a controlled first wheel assembly (Te) and steering a stiff-axle wheel assembly (T2... Tm, Tu) assigned to a further vehicle body (K2...Kn) by an angular rotation opposite to the angular rotation of a preceding vehicle body (K1, Kn-1). The apparatus according to the invention, wherein a device for detecting a value of angular rotation of the controlled wheel assembly (Te) is linked up with a steering mechanism (P) pivotally associated with the first stiff-axle wheel assembly (T1).

Inventors:
SZABÓ ISTVÁN (HU)
Application Number:
PCT/HU2016/050012
Publication Date:
October 20, 2016
Filing Date:
April 13, 2016
Export Citation:
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Assignee:
SZABÓ ISTVÁN (HU)
International Classes:
B62D13/00
Foreign References:
EP2192024A22010-06-02
DE202014103784U12014-08-27
EP0694007A11996-01-31
DE3231367C11984-01-26
EP0536433A11993-04-14
DE102006037588A12008-02-21
DE102012002626A12014-07-03
HU229757B12014-06-30
Attorney, Agent or Firm:
DANUBIA PATENT AND LAW OFFICE LLC (Budapest, HU)
Download PDF:
Claims:
CLAIMS

1. A method for steering a roadway vehicle train comprising at least two vehicle bod- 5 ies (Kl, K2...Kn-l, Kn), a bogie (Fl-Fm) linking two adjacent vehicle bodies (Kl, K2...Kn) and a stiff-axle wheel assembly (Tl-Tm) pivoted on the bogie (Fl-Fm) assigned to a respective vehicle body (Kl, K2...Kn-1, Kn), and the first and last vehicle bodies (Kl, Kn) are provided with a steering wheel assembly (Te,Tu); steering the vehicle train to be moved in a direction by means of the first-in-the-course steering wheel assembly (Te); detecting and transit) mitting a value of angular rotation of said steering wheel assembly (Te), characterized by steering the first-in-the-course stiff-axle wheel assembly (Tl) by a rotation opposite to the angular rotation of the first-in-the-course steering wheel assembly (Te); and steering a stiff-axle wheel assembly (T2... Tm, Tu) assigned to a further vehicle body (K2...Kn) by an angular rotation being opposite to the angular rotation of a vehicle body (Kl, Kn-1) preceding in the 15 course and being proportional to the length (a, b) of a respective vehicle body (Kl ... Kn).

2. Apparatus for steering a roadway vehicle train comprising at least two vehicle bodies (Kl, K2...Kn-l, Kn), a bogie (Fl-Fm) linking two adjacent vehicle bodies (Kl, K2...Kn) and a stiff-axle wheel assembly (Tl-Tm) pivoted on the bogie (Fl-Fm) assigned to a respective vehicle body (Kl, K2...Kn-1, Kn), and the first and last vehicle bodies (Kl, Kn) are pro-

20 vided with a steering wheel assembly (Te,Tu); a device for detecting and transmitting a value of angular rotation of at least one steering wheel assembly (Te,Tu), characterized in that the device for detecting and transmitting the value of angular rotation of the steering wheel assembly (Te) is a swinging arm (PI) pivotally attached to the first stiff-axle wheel assembly (Tl) and connected to the steering wheel assembly (Te) adapted to vary a relative angular po-

25 sition of the first vehicle body (Kl) and the first stiff-axle wheel assembly (Tl) associated thereto; and the apparatus is provided by a device adapted to detect a relative angular position of the vehicle body (Kl, K2 ... Kn-1) and at least one adjacent vehicle body (K2 ... Kn), and to vary the angular position of the adjacent vehicle body (K2 ... Kn) and the stiff-axle wheel assembly (T2-Tm... Tu) associated thereto, as a function of said relative angular position.

30 3. Apparatus according to claim 2, characterized in that the device for detecting and transmitting the value of angular rotation of the steering wheel assembly (Te,Tu) is a swinging arm (Pe), an end of which is pivoted on the steering wheel assembly (Te,Tu) and its other end is pivoted on a lever arm (El) of a single arm lever arrangement swiveled by its fulcrum (Mn) on the vehicle body (ΚΙ,Κη) provided with the steering wheel assembly (Te,Tu).

4. Apparatus according to claim 2, characterized in that the said device adapted to detect a relative angular position of the vehicle body (Kl, K2 ... Kn-1) and at least one adjacent vehicle body (K2 ... Kn), and to vary the angular position of the adjacent vehicle body (K2 ... Kn) and the stiff-axle wheel assembly (T2-Tm... Tu) associated thereto, as a function of said relative angular position, is a Watt linkage comprising a centre point of motion (Mw) pivoted on the adj acent vehicle body ((K2 ... Kn), and a first rocker arm (PI) pivoted on a swivel point (C1,C2, Cm... Cn-l) fixed to the vehicle body (Kl, K2... Kn-l), and a second rocker arm (PI) pivoted on a swivel point (D2, D3, .. Dm) arranged on the stiff-axle wheel assembly (T2... Tm) associated to the adj acent vehicle body (K2... Kn).

5. Apparatus according to claim 2, characterized in that the Watt's linkage swivel point (CI ..Cm) is provided with an axial lock (13) arrangement.

6. Apparatus according to claim 2, characterized in that said device for detecting and transmitting the value of angular rotation of the steering wheel assembly (Te) is an angle transmitter (14) having the input signal of a signal processing unit (15e) arranged on the vehicle body (Kl) provided by the steering gear (Te) as output signal, and a signal processing unit (15) is arranged in each vehicle body (Kl, K2 ... Kn-1), and the signal processing unit (15) is connected to the vehicle body (Kl, K2 ... Kn-1) by one of its ends, and it is connected to an actuator (16) linked to the wheel assembly (T2-Tm) associated with the vehicle body (Kl, Kn-1) and to a signal processing unit (15) arranged on the adjacent vehicle body (K2...Kn), by its other end.

Description:
METHOD AND APPARATUS FOR STEERING A ROADWAY VEHICLE TRAIN

The present invention relates to a method for steering a roadway vehicle train comprising at least two vehicle bodies, a bogie linking two adjacent vehicle bodies and a stiff-axle wheel assembly pivoted on the bogie assigned to a respective vehicle body, and the first and last vehicle bodies are provided with a steering wheel assembly; steering the vehicle train to be moved in a given direction by means of the first-in-the-course steering wheel assembly and detecting and transmitting a value of angular rotation of said steering wheel assembly. The invention also relates to an apparatus for steering a roadway vehicle train comprising at least two vehicle bodies, a bogie (linking two adjacent vehicle bodies and a stiff-axle wheel assembly pivoted on the bogie assigned to a respective vehicle body, and the first and last vehicle bodies are provided with a steering wheel assembly; a device for detecting and transmitting a value of angular rotation of at least one steering wheel assembly.

For conventional articulated buses a steering wheel axle is arranged on the front part of the first vehicle body and a stiff-axle wheel assembly is present on the rear part of the same vehicle body followed by a trailer with a connecting articulation assembly therebetween. The trailer has a further wheel assembly either a stiff-axle type or a steering one. The inner space of the vehicle above axles becomes narrower because of the space requirement of wheels and the wheel assembly. This is the case as well for the articulation itself, where the inner space can be used restrictedly due to the rotating plate. For buses having two articulations the trailer is followed by a further trailer connected by a second articulation alike to the first one.

For the solution disclosed by patent document DE 3231367 (C I) the non-steering, medially situated beam axle wheel assembly of a two part vehicle is placed in the articulation. This vehicle is guided by side wheels. Without those side wheels the vehicle must run instably, but it would be impossible to build continuous guiding means along the full length of the roadway, since any traffic crossing this roadway became impossible.

A solution disclosed by patent publication EP 0536433 (Al) relates to a multi-part roadway vehicle having a single wheel assembly built in the vehicle body by each part of the vehicle. Connection between these parts is provided by a conventional bottom hinge connec- tion. The wheel and the hinge placed separately require much space considerably decreasing the useful surface of the vehicle. Ease of steering requires steering of every wheel, primarily on first and last axles in a different way as on other axles. Description does not disclose any solution relating to either the process of steering or that of driving.

Vehicles controlled fully electronically are also available using the so called by wire technology. These are based on conventional A/B+C or A/B+C+D arrangement type of axles. The core element of the software is a so called "reference vehicle" (ie. DE 10 2006 037 588 (Al)). Due to the arrangement of axles steering this vehicle is a very complicated task in despite of a computer control, moreover, all axles must be individually steered.

Patent publication document DE 10 2012 002626 Al discloses a block diagram of a vehicle. Electric system collects data from the course of a first axle and enables steering of the axles by using data of the course of an actual axle. A rotating actuator as disclosed meets the requirements in case of minor rotations only. Proper operation of the system is queried by inaccuracy of measured data due to potholes to the greater extent the more distant is the actual axle from the first one.

Patent disclosure HU 229 757 describes a hinge assembly having two hinged joints, wherein a traveler is a non steered structure connected rigidly to the hinge and independently from the centre of rotation. The width of turnaround track of the vehicle comprising two vehicle bodies and one hinge assembly amounts to one half of the conventional width, in case of the same length. A hinge assembly according to this document is provided by two center plates and a joint bellow. The structure providing proportional turning of the vehicle bodies is complicated enough and it controls the displacement between vehicle bodies and hinge assembly, but not that of the axles within the hinge.

In order to manage a continuously increasing traffic, vehicles having huge capacity must be brought into service. Use of clean and silent technology is expected chiefly where serving the busiest traffic. Therefore, a pressing need exists of bigger vehicles combining flexibility of bus services and capacity of tramways. For exploiting better the inner space of this vehicle wheels are to be placed advantageously in articulations.

A city tram is a vehicle with big capacity and it is well equipped as well; main ad- vantage of rail-guiding is the separate traffic lane, but this system has several disadvantages, too. In case of service breakdown whole line is stopped soon, since trains cannot overtake each other. Possibility for flexibly managing the traffic of trams is poor especially in case of lines having terminal points without storage tracks. Moreover, traffic of trams is noisy, the environment is charged by strong vibrations. Due to its railway type construction there is a need to run by great arcs of track, because the narrow arcs causes increased wear; switches involve the necessary evil in the system. Only a minor slope can be allowed on a track. But a great advantage of the electric traction that a part of energy can be recovered by breaking resulting in a more economical operation.

One way to increase capacity is increasing speed. Communal vehicles standing about in a traffic jam detract considerably from the standard of service. Use of bus lanes ameliorated this situation and at the same time provided the possibility of applying very long vehicles hav- ing a length more than 24 meters' as well.

Capacity of vehicles for bus transport is relatively small. Since the width of road vehicles is restricted to a maximum of 2.55 m, the only way to increase the capacity is to increase the length of the bus. Operating articulated buses resulted in a need to provide very wide lanes for turns, which cannot be increased further. A requirement to construct articulated road vehi- cles is that all wheels must always follow the same track. This way, length of the bus can be increased freely, so that a vehicle similar to the trams is created.

Therefore, an object of the invention is to eliminate disadvantages of solutions belonging to the state of the art, and to provide a simple method and an apparatus as well for steering a roadway vehicle train, which enable that that all wheels of the vehicle train always follow the same track, that is the track of the previous wheel, even by turning. This way a road vehicle train having perfect track following properties as a whole can be provided.

Above object can be achieved by a method according to the invention for steering a roadway vehicle train comprising at least two vehicle bodies, a bogie linking two adjacent vehicle bodies and a stiff-axle wheel assembly pivoted on the bogie assigned to a respective ve- hide body, and the first and last vehicle bodies are provided with a steering wheel assembly; steering the vehicle train to be moved in a direction by means of the first-in-the-course steering wheel assembly; detecting and transmitting a value of angular rotation of said steering wheel assembly, and steering the first-in-the-course stiff-axle wheel assembly by a rotation opposite to the angular rotation of the first-in-the-course steering wheel assembly; and steer- ing a stiff-axle wheel assembly assigned to a further vehicle body by an angular rotation being opposite to the angular rotation of a vehicle body preceding in the course and being proportional to the length (of a respective vehicle body. The aim above can be achieved also by providing an apparatus according to the invention for steering a roadway vehicle train comprising at least two vehicle bodies, a bogie linking two adjacent vehicle bodies and a stiff-axle wheel assembly pivoted on the bogie assigned to a respective vehicle body, and the first and last vehicle bodies are provided with a steering wheel assembly; a device for detecting and transmitting a value of angular rotation of at least one steering wheel assembly, and the device for detecting and transmitting the value of angular rotation of the steering wheel assembly is a swinging arm pivotally attached to the first stiff-axle wheel assembly and connected to the steering wheel assembly adapted to vary a relative angular position of the first vehicle body and the first stiff-axle wheel assembly associ- ated thereto; and the apparatus is provided by a device adapted to detect a relative angular position of the vehicle body and at least one adjacent vehicle body, and to vary the angular position of the adjacent vehicle body and the stiff-axle wheel assembly associated thereto, as a function of said relative angular position.

The device for detecting and transmitting the value of angular rotation of the steering wheel assembly is a swinging arm, an end of which is pivoted on the steering wheel assembly and its other end is pivoted on a lever arm of a single arm lever arrangement swiveled by its fulcrum on the vehicle body provided with the steering wheel assembly.

The device adapted to detect a relative angular position of the vehicle body and at least one adjacent vehicle body, and to vary the angular position of the adjacent vehicle body and the stiff-axle wheel assembly associated thereto, as a function of said relative angular position, is a Watt linkage comprising a centre point of motion pivoted on the adjacent vehicle body, and a first rocker arm pivoted on a swivel point fixed to the vehicle body, and a second rocker arm pivoted on a swivel point arranged on the stiff-axle wheel assembly associated to the adjacent vehicle body.

The Watt's linkage swivel point is provided with an axial lock arrangement.

The device for detecting and transmitting the value of angular rotation of the steering wheel assembly is an angle transmitter having the input signal of a signal processing unit arranged on the vehicle body provided by the steering gear as output signal, and a signal processing unit is arranged in each vehicle body, and the signal processing unit is connected to the vehicle body by one of its ends, and it is connected to an actuator linked to the wheel assembly associated with the vehicle body and to a signal processing unit arranged on the adjacent vehicle body, by its other end. Therefore, adjacent vehicle bodies of vehicle train, e.g, a bus-chain, steered according to the invention have a stiff bracket and/or a hinged bracket connected to each other by means of a bogie, around which vehicle bodies may turn round. Longitudinal rocking of vehicle is ensured by a rocking axle articulated in the hinged bracket. The rocking axle is a rubber mounting block, which makes it possible a slight lateral bias to occur.

Advantageously, the bus-chain vehicle according to the present invention vehicle bodies are connected to each other as a serial chain and steered by electronically controlled steering actuators. The actuator may be linear displacement actuators - linear motor, hydraulic means- or a servo motor integrated in the bogie. The front axle is steered by the driver. A rate of rotation of the steered axle is measured by an angle-transducer and the measured value hereinafter is transmitted to a signal processing unit by cable. A first signal processing unit is connected to the first actuator, which, based on the signal received, makes the first free rotating stiff axle in the first articulation to rotate in the direction opposite to that of the steering axle and in a range proportional to the axle bases. Rotation occurring between the rigid brack- et and the hinged bracket in the first bogie is measured by a swivel angle transducer and the measured value is forwarded to the first processing unit. The first signal processing unit forwards the signal to the second signal processing, which is connected to the second actuator. Based on the signal received, the second actuator makes the second free rotating stiff axle in the second articulation to rotate in the direction opposite to that of the first vehicle body and in a range proportional to the axle bases. Based on each value measured by each given angle transducer, an actuator connected to the following stiff axle sequentially makes the following stiff axle to rotate in the direction opposite to that of the preceding vehicle body and in a range proportional to the axle bases. The last axle mounted on the last vehicle body is a steered one. The actuator connected to the steering mechanism operates on the basis of the signal of angle transducer measuring the rotation angle between the last and penultimate bodies and the brackets, respectively. The actuator rotates the steering axle in the direction opposite to that of the vehicle bodies and in a range proportional to the axle bases.

Advantageously, the bus chain has driver's stands provided by a control unit for both directions. By activating control unit the driver can select the direction of travel, while he au- tomatically turns off control unit at another stand and the signals to be transmitted properly ensured according to the direction of travel. Overall system - all control units, signal processing units, actuators and angle transducers are connected by cables forwarding signals. With this operating mode, the vehicle is suitable for two-directional running. A vehicle for one-directional running is also possible to form by providing and using a one way control system, indeed.

In a preferred embodiment of vehicle train or bus-chain according to the present in- vention the vehicle bodies are connected in serial connection by mean of mechanical steering rods. Adjacent vehicle bodies have a stiff bracket and/or a hinged bracket connected to each other by means of a bogie. The rocking axle is a rubber mounting block. Wheels are mounted on stiff axles connected to the bogie allowing its rotation independently of the vehicle bodies. Steering axle on the first vehicle body is controlled by the driver. This steering axle is con- nected to the first stiff axle by means of a straight lever linkage. The lever linkage is connected to the steering gear properly, and it rotates the first stiff axle in opposite direction and by a range proportional to the shaft base. The first vehicle body is connected to the second stiff axle via the second vehicle body by means of a Watt's linkage or parallel motion. The centre point of motion of this linkage is fixed to the second vehicle body. Angular motion of the first vehicle body results in a proportional but directionally opposite rotation of the second freely rotatable stiff axle via Watt's linkage. The second vehicle body is connected to the third stiff axle via a similar Watt's linkage, and so on. In each case, the Watt's linkage connects a vehicle body situated before the respective vehicle body and the stiff axle situated after the respective vehicle body. Center point of motion of a Watt's linkage is fixed on the respective vehicle body. The rotation of a preceding vehicle body causes a rotation of the following stiff axle proportional to the axle bases but opposite to the rotation of the vehicle body. The vehicle body situated before the last vehicle body and the steering axle on the last vehicle body are linked by means of a straight lever linkage, in such a way that a rotation of a vehicle body before the last vehicle body causes a rotation of the steering axle proportional to the axle bases but opposite to the rotation of that vehicle body.

In a further preferred embodiment of the chain bus according to the present invention, a serial array of vehicle bodies connected to each other as described above, but the mechanical linkage is provided in two directions. Such a vehicle is suitable for running in both directions. It is necessary that only the linkage according to the direction of travel be active, the other linkage at this time shall be remained ineffective. To this end, the coupling rods of linkages locked to the vehicle bodies must be connected to the respective vehicle body by means of a clutch activating or deactivating the linkage making it effective or ineffective, respectively. Operation of active linkage is the same as described above.

The vehicle comprises in each case a first and a last vehicle body with an arbitrary number of intermediate vehicle bodies, the number of which is limited only by expedience, applied be- tween these two bodies. For electronic steering all the steering elements are identical. For a preferred embodiment of the chain bus the first and last, and any intermediate vehicle body is identical as well. By using these two types of elements a "chain" of any length can be formed. Identical design simplifies the preparation and production and makes it economical as well, whatever the length of the vehicle is. For mechanical steering and for bidirectional design the structure of the first and last vehicle bodies is the same. With a design for riding in a single direction fixing points of connecting rods of Watt's linkage are fixed hinges. The steering mechanism is identical to both first and last vehicle bodies. With a structure having two-way linkage system for bidirectional riding all vehicle bodies are identical.

Alternatively, in an embodiment of the bus-chain, the intermediate vehicle bodies are different from each other, and so the axle bases, that is the distance of axles and the body lengths are different. The power supply or the drive may require shorter vehicle body designed for larger loads in comparison of vehicle bodies used for passenger transport. It is possible to use vehicle bodies of different length might as well use them by alternating arrangement. In these cases, the steering may vary by axles and turning of freely rotating stiff axles is depending on and proportional to the wheelbase.

The invention will be further described in detail with reference to the accompanying drawings. In the drawings:

Fig 1, la, lb shows an embodiment of an apparatus for steering a vehicle train according to the invention,

Fig 2 shows an embodiment of an apparatus suitable for two directional steering a vehicle train according to the invention,

Fig 3 shows a further preferred embodiment of an apparatus for steering a vehicle train according to the invention.

Figure 1 depicts an embodiment of an apparatus for mechanically steering a vehicle train according to the invention.

Intermediate vehicle bodies K2 - Kn-1 are arranged between a first Kl and a last vehicle body Kn, the number of which - within the pale of reason - can be multiplied at will. Connection between vehicle bodies Kl . Kn is established through bogies Fl ...Fm. Stiff-axle wheel assembly Tl - Tm is connected to the respective bogie Fl-Fm, which may turn on this bogie Fl ...Fm independently from vehicle bodies Kl - Kn. Fl-Fm bogie is connected to a stiff bracket 10 and a hinged bracket 1 1. A hinged bracket 11 is connected to a re- spective vehicle body Kl - Kn-1 via a rocking axle 12. A linkage comprising rocker arms PI and Pn establishes connection between vehicle body Kl - Kn-1 preceding a vehicle body K2... Kn and a freely rotatable stiff axle wheel assembly Tl - Tm situated after a vehicle body K2... Kn. First wheel assembly Te being steered by e.g. a driver, and it is connected to the axle Tl via swinging arms Pe, PI, such that an end of swinging arms Pe, PI is fixed to lever arm El pivoted around its fulcrum Ml . Vehicle bodies K2 - Kn-1 are equipped with Watt's linkages each having a fulcrum Mw attached to the respective vehicle body K2 - Kn-1, and also having swinging arms P2, P4, P6 are connected to vehicle bodies Kl, K2, K3 in this order at swivel points CI ... Cm, and having swinging arms P3, P5, Pn -1 are connected to axles T2, T3, Tm at swivel points Dl ... Dm. A wheel assembly Tu arranged on last vehicle body Kn is connected to stiff axle wheel assembly Tm via linear swinging lever arms Pu, Pn, in such a way that one end of arms Pu, Pn is fixed to a lever arm Eu hinged around its fulcrum Mu. Embodiment of steering mechanism as shown in Fig 1 is suitable for moving in direction according to arrow Y.

Wheels of a vehicle train steered by the apparatus according to the invention follow the track, that is wheels mounted on the same side of axles Tl ... Tn belonging to a vehicle body Kl ... Kn run by the same rut, as shown in Fig. la depicting cornering of the vehicle train. By running straight ahead ( Fig 1) stiff axle wheel assemblies Tl ... Tm are perpendicular to the axis Hkn of the vehicle body Kl ...Kn and they must be rotated from this base position to turn. Steering stiff axle wheel assemblies Tl ... Tm of the vehicle train, bogies Fl ...Fm pass on the same turn-circle Zf, and stiff axle wheel assemblies Tl ... Tm are in a position directing in the radius of the turn-circle Zf. Rotational angle a of stiff axle wheel assemblies Tl ... Tm is the same as compared to the adjacent vehicle body e.g. to bodies Kn and Kn-1. That is the central angle β=2α of vehicle body Kn and rotational angle ε=2α of centerline Hkn, Hkn-1 of two adjacent vehicle bodies e.g. Kn, Kn-1 are equal.

By steering, swinging arm PI fixed to axle Tl is moved due to the movement of a single-arm lever pivoted around fulcrum Ml rotated by swinging arm Pe moved by steering axle Te of vehicle body Kl, causing a rotation of axle Tl by an angle a. Since a swinging arm is connected to the first vehicle body Kl, which causes the movement of the swinging arm P3 of the Watt's linkage journaled around fulcrum Mw fixed to the axle T2 in response to turning of vehicle body Kl, it rotates stiff axle wheel assembly also by angle a, and so on, up to rotating wheel assembly Tu by the same angle a. Steering of the last wheel assembly Tu in the course is achieved by a swinging arm Pn fixed to a single- lever arm and attached to the vehicle body Kn-1 and journaled on the body Kn (Fig. 1)

Using vehicle bodies Kn with different lengths a, b within the vehicle train, (Fig. lb), where the length means the length between bogies Fm and Fm-1 of the body Kn, the stiff axle wheel assemblies Tl ... Tm can be steered as follows.

Bogies F l ...Fm passes on the same turn-circle and bogies Tl ... Tm are positioned always in the direction of radius R. At linear motion stiff axle wheel assemblies Tl ... Tm are positioned perpendicularly to the longitudinal axis Hkn of the vehicle body Kl ...Kn and must be steered from this basic position. Their rotational angle as shown in the Figure is e.g. a in relation to vehicle body K2 and β in relation to vehicle body K3. Central angle of the vehicle body K2 is 2a, and that of vehicle body K3 is 2β. Angle of rotation is therefore ε=α+β, since ε =180°-δ-γ, δ=90°-α, γ=90°-β.

By rotation of vehicle body Kn swinging arms P of said Watt's linkages rotate the stiff wheel axle Tm by an angle a resulting in a rotation by angle ε. Distances s, q of fixing points of swinging arms P3,P4 of Watt's linkage determine a splitting rate s/q, where s/q= α/ε.

A further advantageous embodiment of the apparatus for steering a road vehicle train according to the invention is shown in Fig. 2. If the train, e.g a bus-chain, is required to become suitable for bidirectional riding by mechanical steering in both directions depicted by arrow Y, Z, linkage comprising steering swinging arms Pe,Pl ...Pn must be formed in two directions by using swinging arms Pe', Ρ .. P. Only one among the two chain linkages can be effective, the other one serving to the other direction must be turned off, and turned on when the direction of travel changes. This aim is achieved by coupling the Watt's linkages and the swinging arms Ρ,Ρ' to the vehicle bodies K2-Kn through axial clutches 13. Clutch 13 is locked according to the direction of travel, that is the linkage is effective, but in the opposite direction it is open rendering linkage ineffective.

An electronically controlled embodiment of steering apparatus is shown in Fig. 3. By electronic steering, wheel assemblies Tl-Tm are steered by actuators 16. When the rotational angle at the articulation is ε, an actuator supported by vehicle body Ka, stiff axle wheel as- sembly T is adjusted in the direction of the radius in a rate of ε/α, and wheel assembly T supported by vehicle body Kb is adjusted in a rate of ε/β. As actuators 16 linear motors or even hydraulics can be used, or servomotors build in the bogies Fl-Fm or steering assemblies. A rotation between a stiff bracket 10 and a hinged bracket 1 1, that is equal to the relative rota- tion of vehicle bodies Kl, Kn, is measured by transmitters 14 and the signal is transmitted to a processing unit 15 by wires 18. There are driver's stand 19, a controller 17 as well as an actuator 16 built in the steering assembly in both ends of the vehicle. Of course, only one controller 17 according to the actual direction of travel is active in the same time. Two controllers 17 are linked by wire 18 connecting processing units 15 as well. Processing unit 15 transmit a signal according to the direction determined by the controller 17 of travel direction through wire 18 to the actuator 16 connected to the following axle T2-Tu. The travel of the vehicle is determined, therefore, by steering the first axle Te by the driver. Rotation angel of the first axle Te and the last axle Tu is measured by separate angular transmitters 14 built in the steering assembly. Rotation of the last axle Tu is controlled by an actuator 16 directly connected to the steering assembly according to the signal of the processing unit 15, too. Reference signs of the first axle Te and the last axle Tu according to the direction of travel change, reference numerals of axles and vehicle bodies can be defined according to the direction of travel.

Main advantage of the apparatus and method for steering a road vehicle train according to the invention in comparison to the prior art solutions is that the whole vehicle is track following, thet is its length can be chosen freely, a "tram on rubber wheels" is more quite, first and last vehicle bodies ΚΙ,Κη are equal, intermediate vehicle bodies are also equal, the apparatus for steering the road vehicle train unifies the articulation and the bogie Fl-Fm, placing the bogie Fl-Fm in the articulation allows more place within the vehicle, and the same time the possibility of passage within the vehicle is maintained. Articulation angle of the ve- hide is smaller than conventional ones; therefore, the articulation itself can be smaller than that of prior art solutions. The width of the cornering track of the whole vehicle is determined by the cornering track of the longest vehicle body. Arcs of the track can be narrower as compared to those of tram, slopes of the track can be higher, that is even mountain track can be formed. Form of the vehicle bodies Kl-Kn follows the conventional design principles, tradi- tional techniques can be used. Steering is autonomous, it does not require a complicated system involving the whole vehicle, but only a connection between the given vehicle body Kl- Kn and a preceding and following bodies K2-Kn-1 must be formed. A service independent of a guided track can be operated flexibly; a new track can be used periodically or provisionally. Vehicles can easily be managed between different services or lines, and investment costs of "rubber wheeled tram" is essentially lower, than that of a system with guided track. Effective save is 30-70% as compared to a track for tram. The apparatus according to the invention is very simple by using electric steering, and the bidirectional traveling can be easily achievable as well.

By above mentioned properties by using of the apparatus and method for steering a road vehicle train according to the invention a cheap and flexible system for public transport can be achieved. Using identical vehicle bodies Kl-Kn makes the production simpler and economical irrespective of the vehicle size.