Low-deck articulated rail vehicle, particulary a tram

Abstract

 Low-deck articulated rail vehide, particularly a tram, in either 2-car 3-bogie configuration or extended by at least one middle car and one bogie, always equipped with one rotable end bogie /1/ under both, the front and the rear parts of the vehicle, and by one middle bogie /2/ under each joint, i.e. connection between the vehide sections, while both the adjacent bodies of the vehicle are rotably mounted on each middle bogie /2/, each in its own attachment point /3/, while there are the elements of the primary and secondary springing /5/ located in the space between the pairs of individually mounted wheels and drives and brakes, particularly motors, gear boxes, disc brakes and track brakes /6/ are located at the outer sides of wheels with respect to the vehicle longitudinal axe. which allows the floor to be at low standard level even over the bogies, where it s just slightly elevated compared to the rest of the passenger space, while both the floor levels are connected with a barrier free transition consisting of gradually elevated ramps, while the standard passing width of the vehicle is met.

Description

Field of technology

[0001] The invention deals with an arrangement of a low-deck tram car for passenger transport, designed particularly for municipal transport.

The Current State of technology

[0002] Low-deck trams are manufactured with low decks most through the vehicle length, while the height in the range of 350÷450 mm over the rail top may be considered standard and the minimum standard passing width is 600 mm. To keep the deck height at this standard level bogies of these trams are usually equipped with broken axle beams with independently mounted pairs of wheels with common geometrical axis of rotation. These axle beams with independently mounted wheels substitute the standard wheel sets, i.e. pairs of wheels pressed on common axles, and enable passing the floor at the low-deck level even between wheels.

[0003] However where rotable bogies are used, the wheels and the bogie bearing structure between the wheels restrict the passenger space when they turn around the vertical axis towards the vehicle body, that the width X of the passenger space is insufficient at the part over the bogie, thus smaller than standard, see Fig. 1.

[0004] If a low-deck vehicle consists of more sections (cars), where a non-rotable bogie is attached under each odd section, the width Y of the low-deck pass through the vehicle extends to the standard level see (Fig. 2). However it is at the expense of higher wheel wear, as only low bogie rotation around the vertical axis towards the particular vehicle body is possible (approx. 3°) in this instance. This leads to increased forces between the vehicle body and the bogie, and between the wheels and the rails, as most of the rotating movements of the section over the bogie are captured at the contact with the rail. These vehicles have moreover lower number of wheel sets (pairs) than vehicles with high deck level because of lower number of sections and thus also bogies and so the vertical load on one wheel set is higher, which is inconvenient for the operation.

[0005] The passing width for passengers may be enlarged, while the mounting of the vehicle body on bogies remains rotable, by locating the pivoting point of the vehicle body to the vertical centre of the wheel set (pair of opposite wheels). Location of vehicle bodies of adjacent sections of a tram on a single bogie this way enables relative enlargement of the passing width for passengers. However efforts for maintaining low deck level also over the bogies brings space problems, where the bogie cannot be equipped for example by double spring suspension, or these bogies are not equipped with driving mechanisms (patent IT 21163 A/84), or may be equipped with driving mechanisms, but then there is not enough space for disc brakes and the bogie only has block brakes (patent IT1216453). In a two-car vehicle only the middle bogie may be solved this way. the end bogies are rotable with the deck higher by approx. 200 mm.

The Principle of the Invention

[0006] The above disadvantages are removed to considerable extent by articulated low-deck tram vehicle in either 2-car 3-bogie configuration or extended by at least one middle car and one middle bogie, and is based on the principle that it is always equipped with one end bogie under both, the front part and the rear part of the vehicle and with one middle bogie under each joint, i.e. connection between vehicle sections, while both the adjacent bodies of the vehicle are rotably mounted on each middle bogie, each in its own attachment point.

[0007] The bogie arrangement allows the elements of primary and secondary springing to be located in the space between the pairs of independently mounted wheels, and the drives and brakes on the outer side of the wheel in relation to the vehicle longitudinal axe. Thanks to this arrangement the deck over the bogies may also be kept in the standard low level, which is only slightly higher than the rest of the passenger space floor, while both the parts of the floor are connected with a barrier free transition part of slightly elevated ramps, while the passing width of the vehicle remains standard. Connection of the individual sections of the body with the bogies is based on the principle that the pivot points of both of the adjacent bodies of the vehicle on the middle bogie is always geometrically located on the vertical axe going through the centre of rotation of the common rotation axis of one pair of the wheels, and the pivot point of the end bogie is vertically situated on the lengthwise axis of the bogie relatively dose (approx. 1/3 of the bogie wheel base) to the centre of the common rotation axis of the pair of wheels more distant from the vehicle end, which minimizes the relative transversal movement of the appropriate wheels against the vehicle body during rotation around the vertical axis going through the pivot point of the middle bogie, and possibly through the point of attachment of the vehicle body on the appropriate end bogie, which enables just a small restriction of the passing width W of the vehicle then is usual for other vehicles with rotable bogies, i.e. the W dimension remains at the standard width over the middle bogies and is close to the standard width over the end bogies.

[0008] For the end bogies under the front and rear parts of vehicle this advantage only applies to the pairs of wheels closer to the centre of the vehicle, the outer parts show higher range of movement against the vehicle body, however these pairs of wheels do not restrict the passenger space as they move under the driver's cabin at the front and under conveniently arranged seats at the back, for example arranged into an arch over the space where the outer pair of wheels moves (see Fig. 7). The passage width Z to the driver's cabin or to the seats at the back will remain acceptable, adequate to the intensity of passenger move at these areas.

[0009] Each section of the vehicle body mounted on the middle bogie is mounted by means of a bearing, which may be solved as an axial bearing or a tilting spherical bearing arranged on a cradle, while both the cradles on each middle bogie are connected by a rod transferring longitudinal forces between the sections. The rod arrangement and its attachment to the cradles enable the adjacent sections to move mutually along the longitudinal and transversal axes within the directional and vertical guiding of the rails. If spherical bearings are used for attachment of the body sections on the cradles, both the cradles may form a single solid unit, as the mutual movements of the sections around the longitudinal and transversal axes will be enabled in the spherical bearings. The longitudinal forces from the vehicle body sections to the bogie are transmitted by a rod connecting each of the cradles of the middle bogie with the frame of the middle bogie.

[0010] At the end bogies the body is mounted on the bogie by means of a bearing and a cradle with shifted mounting of the vehicle body against the springing sets and thus against the bogie centre. An axial ball bearing is for example used here for attachment of the vehicle body section, as it is capable of transferring the moment caused by eccentric load on the cradle.

[0011] The arrangement of both the bogie types according to the invention will enable a low deck to be kept all through the vehicle length at the standard level, even over the bogies, while the floor is stepless, only with ramps with gradual elevation of maximum 1 : 10, while the passing width of the vehicle over the middle bogies remains at least standard and over the end bogies is 70 % of the standard width, while the vehicle shows very good driving properties thanks to the use of primary and secondary springing, and the vehicle shows very good driving properties and minimum wear of wheels and rails, thank to the rotable mounting of the vehicle body on the bogies, which is unusual for low-deck vehicles, and the wheels of all the bogies may be driven and braked by disc brakes.

Summary of the figures in the drawing

[0012] The solution of the invention is illustrated in enclosed drawings, where Fig. 3 shows a two-car three-bogie configuration, Fig 4 shows a three-car four-bogie configuration, Figs. 5, 6 and 7 show arrangement of the vehicle over the bogies and Figs. 8 and 9 show mounting of the cars on the bogies.

Example of the invention application

[0013] The low-deck rail vehicle, particularly a tram car illustrated in Fig. 3 is arranged in two-car configuration with sections A and B and three bogies.

[0014] The vehicle in Fig. 4. is extended by one section and has four bogies.

[0015] The articulated tram vehicle shown in Fig. 3 is equipped with the first end rotable bogie 1 under the front part of section A and the second end bogie 1 under the rear part of section B and one middle bogie 2 under the articulation - link between sections A and B of the vehicle, while both the adjacent ends of the bodies - sections A and B of the vehicle are rotably mounted on the middle bogie, each in a separate mounting point 3.

[0016] The location of the bogies is illustrated in Figures 8 and 9. Bogies 1 and 2 are arranged in such a position that the elements of primary and secondary springing 5 are located in the space between the pairs of separately mounted wheels of the bogie, and drives and brakes (motors, gear boxes, disc and track brakes) 6 are located on the outer side of the wheel (in relation to the vehicle longitudinal axe). Thanks to this arrangement the deck over the bogies may also be kept in the standard low level, which is only slightly higher than the rest of the passenger space floor, while both the parts of the floor are connected with a barrier free transition part by slightly elevated ramps, while the passing width of the vehicle remains standard. Connection of the individual sections of the body with the bogies is based on the prinaple that the pivot point 3 of the middle bogie 2 is always geometrically located on the vertical axe going through the centre of rotation of the common rotation axis of one pair of the wheels, and the pivot point 4 of the end bogie 1 is vertically situated on the lengthwise axis of the bogie relatively close (approx. 1/3 of the bogie wheel base) to the centre of the common rotation axis of the pair of wheels more distant from the vehide end, which minimizes the relative transversal movement of the appropriate wheels against the vehicle body during rotation around the vertical axis going through the pivot point 3 and possibly through the point 4 of attachment of the vehicle body on the appropriate bogie, which enables just a smaller restriction of the passing width W and Z of the vehicle, then is usual for other vehicles with rotable bogies, while the W dimension remains at the standard passing width of the vehicle. For the end bogies 1 under the front and rear parts of vehicle this advantage only applies to the pairs of wheels closer to the centre of the vehicle, the outer parts show higher range of movement against the vehicle body - however these pairs of wheels do not restrict the passenger space as they move under the driver's cabin at the front and under conveniently arranged seats at the back. The seats in the back part of the vehicle are arranged into arch shape over the space where the outer pair of wheels of the bogie 1 moves, see Fig. 7. The width Z of the passage to the driver's cabin or to the seats at the back will remain acceptable, adequate to the intensity of passenger frequency at these areas.

[0017] Each section of the vehicle body mounted on the middle bogie 2 is mounted by means of a bearing 7, which may be solved as an axial ball bearing or a tilting spherical bearing arranged on a cradle 8, see Fig. 8, while both the cradles 8 on the middle bogie 1 are connected by a longitudinal rod 9 transferring longitudinal forces between the vehicle sections. The rod 9 arrangement and its attachment to the cradles 8 enable the adjacent section to move mutually along the longitudinal and transversal axes within the directional and vertical guiding of the rails. If spherical bearings are used for attachment of the body sections on the cradles, both the cradles may form a single solid unit, as the mutual movements of the sections around the longitudinal and transversal axes will be enabled in the spherical bearings 7. The longitudinal forces from the vehicle body sections to the bogie are transmitted by a rod 10 connecting each of the cradles 8 of the middle bogie 2 with the frame 11 of the middle bogie 2.

[0018] At the end bogies 1 the appropriate section of the vehiGe body is mounted on the bogie by means of a bearing 14 and a cradle 12 with longitudinally shifted mounting of the body 4 against the secondary springing sets 13 and thus against the bogie centre. An axial ball bearing 14 is used at the end bogies 1 for attachment of the vehicle body section, as it is capable of transferring the moment caused by eccentric load on the cradle.

[0019] The arrangement of both the bogie types of a low-deck articulated rail vehicle, particularly a tram, according to the invention will enable a low deck 15 to be kept all through the vehicle length at the standard level usual for low-deck trams, even over the bogies, while the floor is stepless, only with ramps with gradual elevation of maximum 1 : 10, while the passing width of the vehicle over the middle bogies remains at least standard and over the end bogies 1 is 70 % of the standard width, while the vehicle shows very good driving properties thanks to the use of primary and secondary springing, and the vehicle shows very good driving properties and minimum wear of wheels and rails, thank to the rotable mounting of the vehicle body on the bogies, which is unusual for low-deck vehicles. The wheels of all the bogies may be driven and braked by disc brakes.

Industrial applicability

[0020] The solution according to the invention is applicable for low-deck rail vehicles, particularly for trams designed mainly for municipal transport.

Claims

1. Low-deck articulated rail vehicle, particularly a tram, in either 2-car 3-bogie configuration or extended by at least one car and one bogie, characterized by the fact, that it is always equipped with one rotable end bogie /1/ under both, the front and the rear parts of the vehicle, and by one middle bogie /2/ under each joint, i.e. connection between vehicle sections, while both the adjacent bodies of the vehicle are rotably mounted on each middle bogie /2/, each in its own attachment point /3/, while there are the elements of the primary and secondary springing /5/ located in the space between the pairs of individually mounted wheels and drives and brakes, particularly motors, gear boxes, disc brakes and track brakes /6/ are located at the outer sides of wheels with respect to the vehicle longitudinal axis, which allows the floor to be at low standard level even over the bogies, where it s just slightly elevated compared to the rest of the passenger space, while both the floor levels are connected with a barrier free transition consisting of gradually elevated ramps, while the standard passing width of the vehicle is met.

2. Low-deck articulated rail vehicle, particularly a tram, according to Claim 1., characterized by the fact, that connection of each section of the vehicle body is based on the principle that the pivot points /3/ of the connection of the sections with the middle bogie /2/ is geometrically located on the vertical axis going through the centre of the common axis of rotation of one pair of bogie wheels and the pivot point /4/ of the end bogie /1/ is situated on the longitudinal axis of the bogie relatively close, approximately 1/3 of the bogie wheel base to the centre of the common axis of the pair of bogie wheels more distant from the vehicle end, which minimizes the relative transversal movement of the appropriate bogie wheels against the vehicle body when it tums around the vertical axis leading from the pivot point /3/, or also point /4/ of mounting the vehicle body on the appropriate bogie, which results in lower limitation of the passing width W of the vehicle than is usual for vehicles with rotable bogies, i.e. the distance W remains equal to the standard passing width, and is bigger than /X/, and the pass width Z to the driver cabin or to the seats at the back part of the vehicle will remain acceptable, adequate to the intensity of passenger frequency at these places.

3. Low-deck articulated rail vehicle, particularly a tram, according to Claims 1 and 2., characterized by the fact, that each section of the vehicle body is mounted on the middle bogie /2/ by means of a bearing /7/ arranged on one cradle /8/ of the bogie, while both the cradles on each middle bogie are mutually connected with a longitudinal rod /9/, which transfers longitudinal forces between adjacent sections of the vehicle, while the arrangement of the rod /9/ and its attachment to the cradles /8/ enable the adjacent section of the vehicle to move mutually around the longitudinal and transversal axes within the directional and vertical guiding of rails, while the longitudinal forces from the vehicle sections to the bogie are transferred by a rod /10/ always connecting one of the cradles /8/ of the middle bogie /2/ with the frame /11/ of this middle bogie /2/.

4. Low-deck articulated rail vehicle, particularly a tram, according to Claims 1 and 2., characterized by the fact, that the vehicle body is attached to the end bogie /1/ by means of a bearing /14/ and a longitudinally asymmetrical cradle /12/, with the body /4/ longitudinally shifted against the secondary springing /13/, or to the centre of the end bogie /1/, while the bearing /14/ is capable of transferring also the moment caused by the eccentric load of the cradle /13/.

5. Low-deck articulated rail vehicle, particularly a tram, according to Claim 3., characterized by the fact, that the bearing /7/ is an axial ball bearing.

6. Low-deck articulated rail vehide, particularly a tram, according to Claim 3., characterized by the fact, that the bearing /7/ is a tilting spherical one and the cradles /8/ of both the wheel sets of the middle bogie /2/ form a single solid unit.

7. Low-deck articulated rail vehicle, particularly a tram, according to Claim 3., characterized by the fact, that the bearing /14/ is an axial ball bearing.

Drawing