Multi-purpose bogie for rail vehicles

Abstract

 A drive and/or supporting bogie for rail vehicles consisting of a bogie frame (11) provided with a swinging cross-member (12) fixed to hangers (15) in such a manner as to be very close to the ground, ie to the rail plane, each wheel of the bogie being independent and driven separately by its own motor-reduction gear unit (29-30).

Description

[0001] This invention relates to a multi-purpose bogie for rail vehicles, and particularly to a bogie for tramway vehicles of the sunken floor type.

[0002] Tramway vehicles of traditional type generally comprise four-wheel (two-axle) driving bogies having only one or possibly two motors, the mechanical energy of which is distributed to the two axles by a pair of reduction gears.

[0003] Such a structure results in a considerable overall height, which totally determines the floor shape of the vehicle body, and in addition the axles are very large because they support the weight of the reduction gear and of the brake discs, which are of considerable size and weight, there being also difficulties of access to the bogie when the components of the motor-reduction gear unit require maintenance.

[0004] The object of the present invention is to obviate the drawbacks of the said known art by providing a drive and/or supporting bogie for use in tramway vehicles especially of the sunken floor type, without creating size problems and thus enabling the total vehicle height to be reduced, whether this is of one or two-directional single or multiple body type, unidirectional or bidirectional, a bogie easy to upkeep being thus obteined.

[0005] This object is attained by a multi-purpose bogie for a rail vehicle, consisting essentially of a bogie frame provided with a swinging cross-member and a plurality of wheels, said cross-member being connected to said bogie by a secondary suspension and being also provided with a thrust bearing for connection to said vehicle, characterised in that said plurality of wheels are four mutually independent wheels each mounted on its own fork and connected to a primary suspension, said swinging cross-member having a varying cross-section and being connected to said secondary suspension by a hanger in such a manner that the height of the centre line through said cross-member is lower than the height of the axis of rotation of said wheels.

[0006] In a preferred embodiment, four motor-reduction gear units are associated with said four wheels and are arranged to independently drive each of said wheels.

[0007] Again according to the invention said primary suspensions are disposed horizontally.

[0008] Said hanger acts via a suitable plate on a pair of elastic elements which in a preferred embodiment of the invention are helical springs of metal material.

[0009] Further according to the present invention two abutment elements are provided on said cross-member to the sides of said connection thrust bearing, and each wheel is provided with a disc brake.

[0010] In one embodiment of the invention a middle portion of said swinging cross-member is of rectangular plan.

[0011] The technical characteristics and further advantages of the present invention will be more apparent from the following detailed description given with reference to the accompanying drawings in which:

Figure 1 is a partly sectional front view of a carriage according to the invention;

Figure 2 is a plan view of the bogie of Figure 1 from above;

Figure 3 is a side view of the bogie of Figure 1; and

Figure 4 is a side view of a further embodiment of the bogie of Figure 1.

[0012] In the figures the reference numeral 10 indicates overall a bogie according to the invention consisting of a bogie frame 11 provided with a swinging cross-member 12 and a plurality of wheels 13.

[0013] The swinging cross-member 12 is fixed to the bogie frame 11 by a pair of secondary suspensions 14 provided with hangers 15 pivoted at their lower end 16 to the cross-member and at their upper end 17 to plates indicated overall by 18 forming an integral part of the secondary suspension and acting on the elastic elements. On the swinging cross-member 12 there are also provided a thrust bearing 19 for connecting the bogie 10 to a body 20 of a rail vehicle (the body 20 being indicated only schematically) and two abutment elements 21 on which the body rests when travelling through curved rail portions. Each wheel 13 is independent of the others and is mounted on a swinging fork 22 connected to a horizontally reacting primary suspension 23. On each side of the bogie 10 the primary suspensions 23 of each wheel oppose each other via an interposed elastic block 24. The fork 22 is able to swing by virtue of its pivoting at 25 and its articulated connection 26 to the primary suspension 23.

[0014] In addition, each wheel 13 is provided with a brake unit 27, the bogie being also provided with an electromagnetic braking device 28.

[0015] In the case of a drive bogie, a motor unit 29 and respective reduction gear 30 supported by the fork 22 are associated with each wheel 13. In this manner the vertical reactions of the bogie 10 are transformed into horizontal thrusts which are absorbed by the primary suspension 23.

[0016] Using a bogie 10 such as that described means that not only can both a supporting and a drive bogie be obtained by the same basic structure, but that by suitably shaping the bogie frame 11 and the swinging cross-member 12, the region between the wheels can be left free so that vehicles can be constructed with sunken floors which also include that region of the vehicle body in which the drive bogies are present.

[0017] This is because according to the invention the centre line of the swinging cross-member is at a lower height than the axis of rotation of the wheels.

[0018] The bogie structure according to the invention also enables the motor-reduction gear units to be housed in such a manner that their maintenance becomes simple, and in addition if one or more motor units develops a fault the vehicle still has sufficient power to continue operation. Each vehicle is generally provided with at least two drive bogies and consequently with at least eight individual motor-reduction gear units for each wheel, so that for example if two units are out of operation the vehicle will still have 6/8 of its full power available.

[0019] Further according to the invention, the speed of any wheel can be varied independently of the others by acting on the respective motor-reduction gear unit for example by a computerized system. This has the advantage of eliminating the slipping which occurs between the wheel and rail when travelling through curves, so reducing friction, maintenance and costs.

[0020] The present invention has been described by way of non-limiting illustration only, and modifications and replacements can be made thereto by experts of the art, but without leaving the scope of protection of the present invention.

Claims

1. A multi-purpose bogie for a rail vehicle, consisting essentially of a bogie frame provided with a swinging cross-member and a plurality of wheels, said cross-member being connected to said bogie by a secondary suspension and being also provided with a thrust bearing for connection to said vehicle, characterised in that said plurality of wheels are four mutually independent wheels each mounted on its own fork and connected to a primary suspension, said swinging cross-member having a varying cross-­section and being connected to said secondary suspension by a hanger in such a manner that the height of the centre line through said cross-member is lower than the height of the axis of rotation of said wheels.

2. A multi-purpose bogie as claimed in claim 1, characterised in that four motor-reduction gear units are associated with said four wheels and are arranged to independently drive each of said wheels.

3. A multi-purpose bogie as claimed in claim 1, characterised in that said primary suspensions are disposed horizontally.

4. A multi-purpose bogie as claimed in claim 1, characterised in that said hanger acts via a suitable plate on a pair of elastic elements.

5. A multi-purpose bogie as claimed in claim 3, characterised in that said elastic elements are helical springs.

6. A multi-purpose bogie as claimed in claim 1, characterised in that two abutment elements are provided on said cross-member to the sides of said connection thrust bearing.

7. A multi-purpose bogie as claimed in claim 1, characterised in that said swinging cross-member is of rectangular plan.

8. A multi-purpose bogie as claimed in claim 1, characterised in that each wheel is mounted on a swinging fork.

9. A multi-purpose bogie as claimed in claim 8, characterised in that said swinging fork is provided with two articulated connections, a first of said two being provided between said primary suspension and said fork, and the second of said two being provided between said fork and said bogie.

10. A multi-purpose bogie as claimed in claims 1 and 2, characterised in that said motor-reduction gear units for independently driving each of said wheels are supported by said swinging fork.

11. A multi-purpose bogie as claimed in claims 1 and 2, characterised in that said motor-reduction gear units for independently driving each of said wheels are controlled by a logic microprocessor arranged to regulate the speed of each wheel.

Drawing