EP3003771A2

EP3003771A2 - Mechanism for electrical feeding of road vehicles

Info

Publication number: EP3003771A2
Application number: EP14733741.4A
Authority: EP
Inventors: Gunnar Asplund
Original assignee: Elways AB
Current assignee: Elways AB
Priority date: 2013-06-03
Filing date: 2014-05-27
Publication date: 2016-04-13
Also published as: SE1350677A1; WO2014196912A2; SE537192C2; WO2014196912A3

Abstract

Mechanism for electrical feeding of road vehicles comprising a contact device (5) adapted to co-act mechanically and electrically with a track (2) comprising an electric conductor put under voltage and located in a road section on which the vehicle (7) is travelling,in order to supply electric voltage to at least one electric motor which propels the vehicle,wherein the contact device is displaceable vertically and laterally and comprises at least one current collector (8). The mechanism comprises a bar (10) directly or indirectly attached to the vehicle and arranged substantially horizontal and perpendicular to the driving direction of the vehicle and a sliding device (9)adapted to be displaced laterally on the bar, wherein the current collector is connected to the sliding device by means of a contact arm (6) which is displaceable vertically and the mechanism further comprises means for lateral displacement of the sliding device on the bar.

Description

MECHANISM FOR ELECTRICAL FEEDING OF ROAD VEHICLES

The present invention relates to a contact device mechanism for electrical feeding of road vehicles, in order to supply electric voltage to at least one electric motor which propels the vehicle, wherein the contact device is displaceable vertically and laterally and comprises at least one current collector. In a second aspect, the present invention relates to a vehicle comprising such a contact device mechanism.

Technical background of the invention

Concerns about the environmental impact of combustion of fossil fuels have led to an increased interest in electric vehicles, which have several potential benefits compared to vehicles with conventional internal combustion engines, including: a significant reduction of urban air pollution, as they do not emit harmful tailpipe pollutants from the on-board source of power at the point of operation; reduced greenhouse gas emissions from the on-board source of power, depending on the fuel and technology used for electricity generation and/or charging the batteries and reduced dependency on fossil fuels with increasingly variable supply and fluctuating prices.

However, there are factors which discourage consumers from making the switch to electric vehicles. As of 2013, electric vehicles are significantly more expensive than conventional internal combustion engine vehicles and hybrid electric vehicles due to the additional cost of their lithium-ion battery pack. Another hurdle to overcome is the limited range of existing electric vehicles due to limitations in battery capacity.

WO 2010/140964 proposes one solution to the latter problem by feeding electric vehicles while driving. It discloses a system for electric propulsion of a vehicle along a road comprising electric conductors in the shape of conducting rails that may be put under voltage and located in longitudinal tracks or channels in the road. The vehicle is equipped with a current collector which during contact with the conducting rail allows for transfer of electric current between the conducting rail and the vehicle.

The stretch of road carrying the conducting rails is divided into electrically separat- ed road sections oriented in series, whereby the conducting rails are only put under voltage when a vehicle with a current collector passes the relevant road section.

In order for the current collector to make contact with the conducting rails it is mounted on suitable contact device acting as an extension between the vehicle and the conducting rails. One example of a contact device is given in WO 201 1/123046, which is incorporated herein by reference. The contact device is adapted to co-act mechanically and electrically with an electric conductor put under voltage and located in a road section on which the vehicle is travelling, in order to supply electric voltage to the at least one electric motor which thereby propels the vehicle. The contact device compris- es a longitudinal arm, rotatable about two perpendicular rotational axes, which is attached to the underside of a vehicle and may be moved horizontally and/or lowered towards the track.

One drawback with the contact devices proposed by the prior art is that the longitudinal arm requires significant free space underneath the vehicle. Moreover, the overall size and elongated shape make the longitudinal arm difficult to move rapidly, which may be necessary e.g. when the vehicle changes position on the road, or reaches road sections without a track with conducting rails.

Another disadvantage is that the lateral displacement of the arm changes the angle of the current collector in relation to the track, requiring that the current collector is attached to the current collector in a rotatable manner about two axes, similar to how the arm is attached to the vehicle. This leads to further complexity in the design of the contact device according to the prior art.

US 4,227,595 discloses a current transmitting system for use with a self-propelled automatically steered electric vehicle including a pair of parallel, circularly arranged bus bars connected to a low-frequency A.C. power source, and a current collecting shoe slidable on and along each of the bus bars for transmitting the current carried by the bus bar to an electric device mounted in the vehicle. The current collector is mounted on a sliding rod. However, the current collector is intended to be more or less fixedly attached to the bus bars by means of an intricate connection and only minor lateral movement of the vehicle in relation to the bus bars is foreseen.

Therefore, there is a need to develop improved contact device mechanisms which facilitate displacement of contact devices.

Summary of the invention

The purpose of the present invention is to provide improved contact device mechanisms which facilitate displacement of contact devices.

This is achieved by a mechanism according to claim 1 .

According to the present invention, there is provided a mechanism for electrical feeding of road vehicles comprising a contact device adapted to co-act mechanically and electrically with a track comprising an electric conductor put under voltage and located in a road section on which the vehicle is travelling. This in order to supply electric voltage to at least one electric motor which propels the vehicle, either supplementing or replacing the propulsion provided by the existing vehicle engine as the vehicle travels on a an electrified road section, e.g. by the system of WO 2010/140964, which is incorporated herein by reference. The contact device is displaceable vertically and laterally and comprises at least one current collector, preferably in the shape of a sliding contact.

Such a mechanism is described e.g. in WO 201 1/123046, WO 201 1/123048, which are incorporated herein by reference. The mechanism is adapted to sense the presence of an electrified road section and will only then bring the contact means into mechanical and electric contact with the electric conductors, as described in WO

201 1/123052, which is also incorporated herein by reference. Alternatively, the mechanism may be connected to an add-on motor assembly which in turn is connected to the vehicle, as described in WO 2013/141782, incorporated herein by reference.

The mechanism further comprises a bar directly or indirectly attached to the vehicle and arranged substantially horizontal and perpendicular to the driving direction of the vehicle and a sliding device adapted to be displaced laterally on the sliding bar, wherein the current collector is connected to the sliding device by means of a contact arm which is displaceable vertically. In the case of an add-on motor assembly, the bar may be attached thereon, hence the indirect attachment to the vehicle.

In the context of the present application, the term sliding device should be interpreted as a device which may be displaced on the bar, but not necessarily by a sliding motion. Instead any type of suitable translational motion along the bar is foreseen.

As rapid lateral displacement of the vehicle is sometimes necessary, this requires an equally fast lateral displacement of the mechanism carrying the contact device in order to remain in contact with the track and electrical conductor(s). The present invention proposes to mount the displacement mechanism on a substantially horizontally arranged bar which is attached or connected to a vehicle perpendicular to the vehicle's driving direction. By providing a laterally displaceable device on the bar and connected to the contact arm, it is possible to reduce the length of the contact arm, since the contact arm will only be required to be moved vertically, towards and away from the track. Hence, a robust, compact and simple design is achieved which may be rapidly displaced along the width of the vehicle, as well as in the vertical direction towards or away from the track. The mechanism further comprises means for lateral displacement of the sliding device on the bar for actively controlling the position of the sliding device with respect to the vehicle.

In a preferred embodiment, the length of the bar is substantially equal to the width of the vehicle and the sliding device is configured to be displaced along substantially the whole width of the vehicle. This will ensure that the current collector can reach the track in any position underneath the vehicle.

In an advantageous embodiment, the lateral displacement means comprises an electric motor, a hydraulic pump and/or a pneumatic pump. The electric motor may actuate the sliding device directly or indirectly via a wire which may or may not be guided inside a flexible tube. Other suitable means for displacing the sliding device in the lateral direction, such as a gear system, rack and pinion or a linear actuator may also be considered.

In an alternative embodiment, the mechanism further comprises means for vertical displacement of the contact arm. Preferably, the vertical displacement means comprises an electric motor, a hydraulic pump and/or a pneumatic pump. The electric motor may actuate the contact arm directly or indirectly via a wire which may or may not be guided inside a flexible tube. Other suitable means for displacing the contact arm in the vertical direction, such as a gear system, rack and pinion or a linear actuator may also be considered.

In a further preferred embodiment, the contact arm is flexible in the axial direction and adapted to be pressed against the track. Preferably, the contact arm is arranged vertically such that the current collector is located substantially directly underneath the sliding device. This allows for even further reduction of the length of the contact arm and facilitates control of the movements thereof. By making the contact arm flexible, it may be configured to dampen or compensate for vibrations, shocks and/or movements in the vertical direction caused by e.g. uneven road surface. Hence, the mechanism and contact device will be able to withstand such loads without risking damage.

In an advantageous embodiment, the bar is configured to be integrated into a bumper of the vehicle. Hence a compact and aesthetically pleasing design is achieved which does not considerably alter the appearance and dimensions of the vehicle.

In a second aspect of the present invention, there is provided a vehicle comprising at least one mechanism according to any of the preceding embodiments. Brief description of the drawings

Fig. 1 illustrates a cross-sectional view of a road section having tracks comprising electrical conductors.

Fig. 2 illustrates a front view and view from above of a vehicle having a contact device mechanism according to the prior art.

Fig. 3 illustrates a front view and view from above of a vehicle having a contact device mechanism according to the present invention.

Fig. 4 illustrates a side view of a vehicle having a contact device mechanism according to a first embodiment of the present invention.

Fig. 5 illustrates a side view of a vehicle having a contact device mechanism according to a second embodiment of the present invention.

Detailed description of the invention

Preferred embodiments of a contact device according to the present invention will now be described with reference to the attached drawings. The invention should not be considered to be limited to the embodiments shown in the attached drawings, but may be varied within the scope of the claims.

Fig. 1 shows a cross-sectional view of a road section 1 having tracks 2 located therein adjacent the road surface. The tracks 2 comprise at least one electrical conduc- tor, preferably two, which may be electrically insulated in all directions except upwards towards the road surface. In Fig. 1 two parallel tracks 2 are shown, but road sections 1 having more than two tracks 2 comprising electrical conductors, e.g. one for each driving lane of the road section 1 , are also contemplated. Also shown in Fig. 1 are low and high voltage cables 3, 4 for supplying electric voltage to the electrical conductors.

In Fig. 2 a mechanism for a contact device 5 according to the prior art, as disclosed in WO 201 1/123046, is illustrated in a front view and view from above. The contact device 5 is mounted on an elongate arm 6 which in turn is attached in a rotatable manner to the underside of a vehicle 7. At the opposite end of the arm, a current collector is attached and configured to be brought into mechanical and electrical contact with the electrical conductors in the track 2 located in a road section 1 on which the vehicle 7 is traveling. Upon electrical contact with the conductors, the current collector feeds an electric motor which propels the vehicle 7.

In order to be brought into contact with the track 2, the elongate arm 6 comprising the contact device 5 may be moved laterally through rotation about a rotational axis perpendicular to the underside of the vehicle 7, and thus to the plane of the road section 1 , as shown by the arrow a in Fig. 2. Additionally, the contact device 5 may be lowered towards or raised away from the track 2 through rotation of the arm 6 about a horizontal axis of rotation perpendicular to the first rotational axis. The disadvantages of the elon- gate arm 6 are that it requires considerable free space underneath the vehicle 7 and that it is difficult to move quickly. Moreover, the lateral displacement of the arm 6 changes the angle of the current collector in relation to the track 2, requiring that the current collector 8 of the contact device is attached to the arm 6 in a rotatable manner, similar to how the arm 6 is attached to the vehicle 7. This leads to further complexity in the design of the contact device 5 according to the prior art.

Shown in Fig. 3 is a contact device 5 and mechanism according to the present invention. The mechanism comprises a sliding device 9 which is configured to be displaced along a bar 10 attached to the vehicle 7 and arranged substantially horizontal and perpendicular to the driving direction of the vehicle 7, as illustrated by the dashed arrow b in Fig. 3. Advantageously, the bar 10 may be incorporated into the front or rear bumper of the vehicle 7 to achieve a compact design which does not substantially alter the appearance and/or physical dimensions of the vehicle 7. Naturally, the bar 10 may be attached or fastened to the vehicle 7 in any suitable manner which allows lateral displacement of the sliding device 9 along the bar 10. Also, in the case of an add-on motor assembly according to PCT/SE2013/050245, the bar 10 may be attached to the add-on motor assembly (not shown), which in turn is connected to the vehicle 7.

Since the sliding device 9 is not restricted to a fixed lateral position in relation to the vehicle 7, lateral displacement means for the contact device 5 may be separated from vertical displacement means for the contact device 5. This allows for more rapid and controllable displacement of the contact device 5. Another advantage compared to the prior art is that a contact arm 6 connecting the sliding device 9 and the current collector 8 may be made much shorter, which further increases possible displacement speed and facilitates control of the contact device 5.

The means for lateral and vertical displacement of the sliding device 9 and the contact arm 6, respectively, may be any of an electric motor, a hydraulic pump and/or a pneumatic pump. The electric motor may actuate the sliding device 9 or contact arm 6 directly or indirectly via a wire which may or may not be guided inside a flexible tube for protection. Other suitable means for displacing the sliding device 9 or contact arm 6 in the lateral or vertical directions, respectively, may also be considered, such as a gear system, rack and pinion a linear actuator or any combination of the above.

Preferably, the bar 10 has a length which is substantially equal to the width of the vehicle 7, such that the sliding device 9 may be displaced along the whole width of the vehicle 7 in order to reach the track 2 in the road section 1.

Fig. 4 illustrates the contact device mechanism in a side view, wherein the reduced length of the contact arm 6 is visualised. The current collector 8 may be brought into mechanical and electrical contact with the track 2 through lowering of the contact arm 6 as illustrated by dashed arrow c in Fig. 4. The significantly shorter contact arm 6 of the present invention requires less space and may be moved faster and with increased control than the prior art. Also, since the contact arm 6 is only moved in a vertical plane parallel to the driving direction of the vehicle 7, the current collector 8 does not require additional longitudinal alignment in relation to the track 2, as is the case with the prior art.

Fig. 5 illustrates a second embodiment of a contact device mechanism according to the present invention. In this embodiment, the contact arm 6 is flexible in the axial direction, i.e. along a longitudinal extension thereof. This enables the contact arm 6 to be arranged vertically, substantially directly underneath the sliding device 9. The flexible nature of the contact arm 6 allows it to dampen or compensate for vibrations or shocks experienced by the contact device 5, e.g. when the current collector 8 encounter objects or obstacles in the track 2 or when the vehicle 7 travels on an uneven road surface causing movement in the vertical direction. The advantage of this is an even more compact design which does not substantially protrude from the vehicle 7.

In this embodiment, the vertical displacement is made even simpler in that the cur- rent collector 8 and contact arm 6 may be lowered and raised without rotation of the contact arm 6 in the vertical plane parallel to the driving direction of the vehicle 7, as illustrated by dashed arrow d in Fig. 5.

Claims

1 . Mechanism for electrical feeding of road vehicles (7) comprising a contact device (5) adapted to co-act mechanically and electrically with a track (2) comprising an electric conductor put under voltage and located in a road section on which the vehicle (7) is travelling, in order to supply electric voltage to at least one electric motor which propels the vehicle (7), wherein the contact device (5) is displaceable vertically and laterally and comprises at least one current collector (8), wherein the mechanism comprises a bar (10) directly or indirectly attached to the vehicle (7) and arranged substantially horizon- tal and perpendicular to the driving direction of the vehicle (7) and a sliding device (9) adapted to be displaced laterally on the bar (10), characterised in that the current collector (8) is connected to the sliding device (9) by means of a contact arm (6) which is displaceable vertically, and that the mechanism further comprises means for lateral displacement of the sliding device (9) on the bar (10).

2. Mechanism according to claim 1 , wherein the length of the bar (10) is substantially equal to the width of the vehicle (7) and the sliding device (9) is configured to be displaced along substantially the whole width of the vehicle (7).

3. Mechanism according to claim 1 or 2, wherein the lateral displacement means comprises an electric motor, a hydraulic pump and/or a pneumatic pump.

4. Mechanism according to any preceding claim, further comprising means for vertical displacement of the contact arm (6).

5. Mechanism according to claim 4, wherein the vertical displacement means comprises an electric motor, a hydraulic pump and/or a pneumatic pump.

6. Mechanism according to any preceding claim, wherein the contact arm (6) is flexi- ble in the axial direction thereof and adapted to be pressed against the track (2).

7. Mechanism according to claim 6, wherein the contact arm (6) is arranged vertically.

8. Mechanism according to any preceding claim, wherein the bar (10) is configured to be integrated into a bumper of the vehicle (7).

9. Vehicle (7) comprising at least one mechanism according to any preceding claim.