The invention relates to a bogie for a rail vehicle, the bogie comprising a bogie frame arranged to be fastened to the rail vehicle; two longitudinal beams of the bogie frame that are provided on opposite sides of the bogie and parallel to a direction of travel of the bogie; and rail wheels supported on the longitudinal beams, adjacent thereto. The bogie may be a pivoting one or a "fixed" one, in which case it may pivot slightly only within the limits allowed by the springiness of the bogie. The invention also relates to a carriage structure for a rail vehicle provided with such a bogie.
Conventionally in the bogies of a low-floor carriage designed for a 1.34 to 1.65 metre gauge, the longitudinal beams of the bogie frame and the support for the rail wheels are implemented by mounting the longitudinal beams in a space between the rail wheels, in which case the longitudinal beams determine a width of an aisle formed symmetrically therebetween inside the carriage. Examples of prior art bogies and carriage structures of this kind are known from
A problem with this solution is how, when necessary, to place the aisle of the carriage and arrange the seats asymmetrically, for instance in a pattern of 2 + 1 rather than in a symmetrical pattern, since the width of the aisle is limited because of the aforementioned conventional bogie structure. An example of prior art bogie and carriage structure showing a partial asymmetry in the arrangement of the longitudinal beams with respect to a centre line of the bogie is known from
An object of the invention is thus to solve the problem described above. This object is achieved by a bogie and a carriage structure according to the invention, which is defined by the technical features set forth in independent claims 1 and 7. The bogie and the carriage structure defined in said claims, respectively, are inter alia characterized in that one longitudinal beam is placed within an area between the rail wheels located on the opposite sides of the bogie, and the other longitudinal beam is placed outside said area between the rail wheels, at an outer edge of the bogie, the longitudinal beams thus being located asymmetrically with respect to a centre line of the bogie. Preferred embodiments of the invention are disclosed in the dependent claims.
The invention is thus based on the asymmetrical placement of the longitudinal beams of the bogie frame with respect to the centre line of the bogie.
In a preferred embodiment, a side of the bogie where the longitudinal beam is located within the area between the rail wheels is provided with bogie traction devices, preferably at the outer edge of the bogie, and a side of the bogie where the longitudinal beam is located outside the area between the rail wheels is provided with bogie braking devices, preferably at the outer edge of the bogie.
It is also possible that the side of the bogie where the longitudinal beam is located within the area between the rail wheels is provided with a combination of bogie traction and braking devices, preferably at the outer edge of the bogie. This may be implemented at least when a driving motor itself is not located in the bogie.
An advantage of the bogie according to the invention is that the aisle of the carriage can be made considerably wider without substantially impairing the use and driving properties of the carriage. This enables the seats to be arranged considerably more freely, when necessary. The solution according to the invention is applicable to rail vehicles designed for a gauge substantially of the order of 1.34 to 1.65 metres.
The invention is now described in closer detail by means of one preferred embodiment thereof and with reference to the accompanying drawings, in which
In a structure according to the invention, the essential point is that one longitudinal beam 7 of the bogie 4 is placed within an area between the rail wheels 9 located on the opposite sides of the bogie 4, and the other longitudinal beam 8 is placed outside said area between the rail wheels 9, at an outer edge of the bogie 4, the longitudinal beams 7 and 8 thus being located asymmetrically with respect to the centre line of the bogie 4 and the carriage structure 1.
Appropriately, in this example a side of the bogie 4 where the longitudinal beam 7 is located within the area between the rail wheels 9 is provided with traction devices 10 of the bogie 4. This arrangement is the most readily implementable since this side has more space available for the traction devices 10, which often require more space than braking devices. The traction devices 10 are then preferably located at the outer edge of the bogie 4.
Correspondingly, a side of the bogie 4 where the longitudinal beam 8 is located outside the area between the rail wheels 9 is provided with braking devices 11 of the bogie 4. The braking devices 11 usually take less space than the traction devices 10, so they can be accommodated on this side even if the longitudinal beam 8 is located outside the rail wheels 9, less space being thus available for the placeable components than on the opposite side. The braking devices 11 are then preferably located at the outer edge of the bogie 4.
It can be seen in
The above description of the invention is only intended to illustrate the basic idea of the invention. A person skilled in the art may thus vary its details within the scope of the attached claims. Consequently, solutions exist for the placement of the traction and braking devices also other than those described herein, including solutions where the traction device only includes gears and clutches necessary for transmitting power but the driving motor itself is not located in the bogie.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.