ES2772623B2 - BRIDGE ASSEMBLY FOR A HEAVY VEHICLE - Google Patents

Description

DESCRIPTION

BRIDGE ASSEMBLY FOR A HEAVY VEHICLE

Cross reference to associated patent applications

This application claims priority from Italian Patent Application No. 102018000021025 filed on December 24, 2018, the content of which is incorporated herein by reference.

technical field

The present invention refers to a traction system for commercial vehicles and in particular to an electric and modular traction system for commercial vehicles.

Known state of the art

The use in commercial vehicles of traction systems driven by internal combustion engines is known, normally connected to a rigid rear axle, that is to say to a cross-bearing part, the axle, which rigidly connects the two wheels and contains the two traction axle shafts. of the wheels connected to each other by a differential. This rigid bridge is connected to the vehicle frame by means of the suspensions, as schematically illustrated in figure 1.

In said figure 1, the rigid bridge 1' of a vehicle 10' essentially comprises a bridge 2' that connects the right wheel and the left wheel 3', 4' at their respective ends and carries the differential 5' in a known manner, in the center of bridge 2'. The bridge 2' is connected to a frame 6' of the vehicle 10' by means of the respective suspensions 7', 8' of any type.

A rigid bridge structure 1' of the type shown in figure 1 allows heavy loads to be transported reliably and the displacement geometry of the wheels to be kept in a controlled manner, reducing their wear.

However, the rigid bridge 1' needs to be reconfigured each time the magnitude in the bridge and the powers involved change and therefore the structure of the bridge 2' and the differential 5' must be reconfigured. This need is even more apparent in the electric/hybrid traction sector where it is necessary to provide a location for the electric traction motor, the size of which varies depending on the torque supplied.

Consequently, there is a need to have a traction system that it is as versatile as possible and that it can be used in different vehicles with different types of axle, suspension and transported weight.

In other words, there is a need for a system that can satisfy the capacity of the transmission components regardless of their power.

The object of the present invention is to satisfy these needs.

Summary of the invention

Said objective is achieved with a bridge assembly provided with a modular electric traction system as shown in the attached claims.

Brief description of the drawings

For a better understanding of the present invention, a preferred embodiment is described below, merely by way of non-limiting example and in relation to the attached drawings, in which:

figure 1 illustrates a schematic rear view of a rigid bridge traction system according to the known technique;

Figure 2 illustrates a first embodiment of a modular electric traction system;

Figure 3 illustrates a second embodiment of a modular traction system;

figure 4 illustrates a rigid axle traction system comprising a modular traction system according to figures 2 and 3;

figure 5 illustrates a rigid bridge traction system comprising a modular traction system according to figures 2 and 3; Y

figure 6 illustrates a drive system with independent suspension on the wheels comprising a modular electric drive system according to figures 2 and 3;

Detailed description of the invention

Figures 2 and 3 schematically illustrate an electric traction module 1. This electric traction module 1 essentially comprises at least one electric motor 2 and a mechanical transmission system 3 configured to carry the mechanical torque supplied by at least one electric motor 2 to a pair of axle shafts 4, 5 of a vehicle 10 each configured to carry a wheel at one end, for example the rear wheels of a commercial vehicle, as described below.

Advantageously, at least one electric motor 2 and the mechanical transmission system 3 are both housed inside a casing 8 configured to delimit an internal volume 9 suitable for this purpose.

In the first form of embodiment, figure 2, the electric traction module 1 comprises a single electric motor 2a housed within the internal volume 9 defined by the casing 8 connected through the mechanical transmission system 3 to a left semi-axle and a right semi-axle 5, configured to carry respective wheels as indicated above.

The electric motor 2a is sized to be able to provide a torque that allows moving a 3.5-tonne vehicle, therefore, it is capable of providing a power P preferably between 80 kW and 150 kW, in order to provide approximately 500 Nm of torque to the wheels (total of the two drive wheels).

The transmission system 3, in the case described, comprises a first toothed wheel 11 carried by an output shaft of the electric motor 2a and coupled with a second toothed wheel 12 carried by an intermediate shaft 13. The intermediate shaft 13 also carries a second toothed wheel 14 meshing with a differential 15, of known type.

The differential 15, as is known, consists of a pair of output shafts 16, 17 each connected to the respective half shafts 4, 5 through a respective CV joint 18, 19, for example a cardan universal joint.

In the second embodiment, Figure 3, the electric drive module 1 comprises a pair of electric motors 2a, 2b each housed within a respective internal volume 9a, 9b defined by casings 8a, 8b. The casings 8a, 8b are advantageously solidly connected to each other.

The electric motors 2a, 2b are sized to provide, together, a sufficient torque to move a 7-tonne vehicle, therefore, each of them is capable of providing a power P substantially similar to that of the module in figure 1.

Therefore, globally the module of figure 3 can provide a power of 2P, that is to say preferably between 160 kW and 300 kW; which corresponds to about 10,000 Nm of torque at the wheels. More preferably module 1 of figure 3 can also include reducers with epicyclic wheels located at the output on the axle shafts, or on the wheels, to further increase the reduction ratio, up to a maximum of 2-3 times, For example, it is possible to obtain torques in the wheels of a value greater than 10,000 Nm, for example, for heavy vehicles of up to 18 tons it is possible to obtain supplied torques of the order of 30,000 total Nm.

Therefore, it is possible to envisage electrical traction modules 1 in which the electric motor 2 and transmission 3 are configured to provide power N times P where P is the power of a base module and N is an integer between 1 and 2.

In the described example the mechanical transmission system 3 is a separate system for each semi-axle 4, 5 and comprises a first gear system 20a and a second gear system 20b configured respectively to connect the first and second electric motors 2a, 2b with the semiaxis 4, 5.

In particular, the first gear system 20a may include a first gear wheel 21a carried by an output shaft of the electric motor 2a and engaged with a second gear wheel 22a carried by an intermediate shaft 23a. The intermediate shaft 23a furthermore carries a second gear wheel 24a coupled with a gear wheel 25a carried by an output shaft 16 connected to the left semi-axle 4 by means of a respective first CV joint 18, for example a cardan universal joint.

In a preferably mirror-like manner, the second gear system 20b may include a first gear wheel 21b carried by an output shaft of the electric motor 2b and coupled with a second gear wheel 22b carried by an intermediate shaft 23b. The intermediate shaft 23b further carries a second gear wheel 24b coupled with a gear wheel 25b carried by an output shaft 17 connected to the left semi-axle 5 by means of a respective second CV joint 19, for example a cardan universal joint.

The electric traction module 1 can advantageously be associated with a rear suspension system of a vehicle as described below.

Referring to Figure 4, a vehicle 100 equipped with a frame 101 suspended, as described below, relative to a rigid bridge assembly 30 according to a first embodiment of said system, is illustrated.

Rigid bridge assembly 30 comprises a cross member 31, substantially a rigid bar, rigidly connecting a pair of wheels 102 to each other.

103 of the vehicle 100. Said crosspiece 31 is also connected to the frame 101 of the vehicle in a mobile manner, advantageously by elastic damping devices 104, of known type, such as leaf springs or a multi-link system and coil springs.

The electric traction module 1 is carried by the frame 101, advantageously integral with the latter, and the axle shafts 4, 5 are connected to the wheels 102, 103 in a known manner.

Referring to Figure 5, a vehicle 100 equipped with a frame 101 suspended, as described below, relative to a rigid bridge assembly 40 according to a second embodiment of said system.

The rigid bridge assembly 40 comprises a crosspiece 41 rigidly connecting a pair of wheels 102, 103 of the vehicle 100 to each other. Said crosspiece 41 is also connected to the frame 101 of the vehicle in a movable manner, advantageously by means of elastic damping devices. 104, of known type, such as leaf springs or a multi-link system and coil springs.

The crosspiece 41 also defines a structure resistant to the loads that the frame 101 transmits to the latter, while preventing them from being transmitted to the module 1. In the example described, the intermediate crosspiece defines a space 42, axially delimited by the two upper and lower parts 41a, 41b of the cross piece 41 and laterally by the end parts and connecting with the wheels 102, 103.

The electrical traction module 1 is advantageously carried by the crosspiece 41 inside the interior volume 42, preferably in a mobile manner.

Advantageously, the mobile connection between the casing 8 and the electrical traction module 1 and the crosspiece 41 comprises at least elastic damping devices 43 that movably connect the casing 8 to the parts 41a, 41b at least vertically.

Referring to figure 6, a vehicle 100 is illustrated equipped with a frame 101 suspended with respect to its wheels 102, 103 as described below thanks to a system of independent suspensions 50.

The independent suspension system 50 consists of a known-type suspension 51, 52 for each wheel 102, 103 configured to connect the latter to the frame 101 of the vehicle 100. These suspensions 51, 52 can each comprise, for example, a plurality of arms 53 and elastic damping devices 54 that connect the respective wheel 102, 103 to a housing part 55 carried by the frame, preferably integrally.

The electrical traction module 1 is advantageously carried by the housing part 55, if possible integrally. The housing part 55 preferably comprises a flange that extends from the frame 101 towards the ground.

From all that has been said so far, the advantages of the electric traction module 1 and of the bridge assembly described above are evident.

The electric traction module 1 can be used in a modular way in a variety of vehicles equipped with suspensions of different types, independent or rigid bridge.

In particular, the electric traction module 1 can be sized for different types of vehicle/tonnage by varying the number of associated electric motors and/or the type of transmission.

The electric traction module 1 can be carried by the axle itself, thus freeing the frame 1 from limitations that can be used on different types of axles.

As previously mentioned, the electric traction module 1 can be used in different types of suspension, rigid bridge, or in independent suspensions, favoring economies of scale.

Lastly, it is clear that the electric traction module 1 and the bridge assembly made according to the present invention can be modified and variants that, however, are not outside the scope of protection defined by the claims.

As mentioned, the number of electric motors and the type of transmission can vary depending on the power that the electric traction module 1 must provide.

And, in addition, several types of suspension can use the electric traction module 1. For example, the rigid part 41 can define different spaces or shapes to carry the electric traction module 1, different from the space 42 described as an example in the present application. .

Claims (8)

1.

- Bridge assembly (40) for a heavy vehicle, said bridge assembly (40) comprising a cross piece (41) that has an interior space (42) delimited by an upper and a lower part (41a, 41b) and that connects at least one pair of wheels (102, 103) rigidly interconnected, said bridge assembly (40) comprising an electric traction module (1), movably carried by said crosspiece (41), said traction module comprising least one electric motor (2), a first and a second output shaft (16, 17) and a transmission (3) configured to connect said at least one electric motor (2) with at least one of said first and second output shafts outlet (16, 17), said electrical traction module (1) further comprising a casing (8), connected to the upper and lower part (41a, 41b) of the crosspiece (41) by means of elastic damping devices (43) , configured to define a volume (9) inside which said motor and power (2) and said transmission (3) and at least part of said first and second output shafts (16, 17). 2. - Assembly according to claim 1, further comprising a first and a second half shaft (4, 5), said first half shaft (4) being connected to said first output shaft (16) by means of a first CV joint (18) and said second half shaft (5) being connected to said second output shaft (17) by means of a second CV joint (19). 3.

- Assembly according to claims 1 or 2, in which said module comprises a single electric motor (2a) and in which said transmission (3) comprises a differential (15) connected to both said first and second output shafts (16, 17). 4. - Assembly according to claims 1 or 2, wherein said module comprises a first electric motor (2a) and a second electric motor (2b), said transmission (3) comprises a first gear system (20a) connecting said first electric motor (2a) to said first output shaft (16) and a second gear system (20b) connecting said second electric motor (2b) to said second output shaft (17). 5. - Assembly according to one of the preceding claims, wherein said transmission (3) comprises epicyclic gears. 6.

- Assembly according to one of the preceding claims, in which said at least one electric motor has a base power P between 80 and 150 kW. 7.

Traction module according to claim 6, wherein said at least one electric motor (2) and said transmission (3) are dimensioned to offer a module with a power of N times the base power P, where N is a pre-established integer between 1 and 2. 8.

- Vehicle (100) comprising a rigid bridge assembly (40) according to any one of the preceding claims.