TECHNICAL FIELD

The invention relates to an electrically propellable vehicle comprising a current collector adapted to co-act with a rail element being located in a road section on which the vehicle is adapted to travel, the rail element being provided with at least one electric conductor being adapted to be put under voltage for supplying electric power to the vehicle. The invention further relates to a corresponding method.

BACKGROUND

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, the expense, weight and limited capacity of the lithium-ion battery packs of today limit widespread use of electric power as the main source of power in vehicles.

WO 2011/123046 proposes complementing the battery of the electric vehicle with electric feeding of the vehicle while driving. A system is disclosed for electric propulsion of a vehicle along a road comprising rail elements/structures having grooves provided with electric conductors therein 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 electric conductors allows for transfer of electric power between the electric conductors and the vehicle to propel the vehicle and charge its battery or set of batteries. One problem with the current collector in this publication is that its vertical extension may be too high to be used in electric passenger cars, which often have quite low ground clearance due to the battery pack being arranged in the floor pan of the car.

SUMMARY

An object of the invention is to solve or improve on the problem mentioned above in the background section.

These and other objects are achieved by the present invention by means of an electrical propellable vehicle and a method for providing an electrical connection according to the independent claims.

According to a first aspect of the invention, an electrically propellable vehicle is provided, which vehicle comprises at least one current collector, each being adapted to co-act with at least one rail element comprising at least one electric conductor, which may be arranged in at least one groove in the rail element, and being adapted to be put under voltage for supplying electric power to the vehicle, the at least one rail element being located in or on a road section on which the vehicle is adapted to travel, wherein each current collector comprises at least one contact element, each contact element being adapted to connect mechanically and electrically with a corresponding contact portion of the at least one electric conductor. The vehicle further comprises a sliding device being displaceable in a lateral direction of the vehicle at an underside thereof. Each current collector may be rotatably connected to the sliding device to rotate around a rotational axis between a folded-down position where the at least one contact element of the current collector is substantially vertically disposed, and a folded-up position where the at least one contact element is non-vertically disposed. The at least one contact element of the current collector may be vertically displaceable relative the vehicle or relative sliding device in the folded-down position.

According to a second aspect of the invention, an arrangement for electrical feeding of an electrically propellable vehicle is provided, which arrangement comprises at least one current collector, each being adapted to co-act with at least one rail element comprising at least one electric conductor, which may be arranged in at least one groove in the rail element, and being adapted to be put under voltage for supplying electric power to the vehicle, the at least one rail element being located in or on a road section on which the vehicle is adapted to travel, wherein each current collector comprises at least one contact element, each contact element being adapted to connect mechanically and electrically with a corresponding contact portion of the at least one electric conductor. The arrangement further comprises a sliding device being displaceable in a transversal direction relative a direction of travel. Each current collector may be rotatably connected to the sliding device to rotate around a rotational axis between a folded-down position where the at least one contact element of the current collector is substantially vertically disposed, and a folded-up position where the at least one contact element is non-vertically disposed. The at least one contact element of the current collector may be vertically displaceable relative the sliding device in the folded-down position.

According to a third aspect of the invention, a system is provided, which system comprises an electrically propellable vehicle according to the first aspect of the invention and at least one rail element comprising at least one electric conductor, which may be arranged in at least one groove in the rail element, and being put under voltage for supplying electric power to the vehicle, the at least one rail element being located in or on a road section on which the vehicle is adapted to travel.

In other words, the vehicle, arrangement and system comprise a sliding device being displaceable in a lateral or transversal direction and being arranged or adapted to be arranged at an underside of the vehicle. Each or at least one current collector may be rotatably connected to the sliding device to rotate around a rotational axis between a folded-down or lowered position where the at least one contact element of the current collector, or the current collector as a whole, is substantially vertically disposed, i.e. lies in a substantially vertical plane, and a folded-up or raised position where the at least one contact element is non-vertically disposed, i.e. forms an angle with the vertical plane, and the at least one contact element of the current collector may be substantially vertically displaceable relative the vehicle or sliding device in the folded- down or lowered position, i.e. is displaceable in a substantially vertical plane. Put differently, at least one or each current collector is foldably attached to the sliding device to be displaceable between the above described folded-down or lowered position and folded-up or raised position. Put differently, each current collector is rotatably connected to the sliding device to rotate laterally and vertically, i.e. rotate in a sideways and upwards/downwards direction, between the folded-up or raised position and the folded-down or lowered position.

It is understood that the above-mentioned vertical direction and vertical plane are defined in relation to the vehicle, i.e. if the vehicle is not arranged at a horizontal road surface, the vertical direction as used herein deviates from the plumb line. In the same sense, the terms horizontal direction, horizontal plane, longitudinal direction and lateral direction are also defined in relation to the vehicle. It is further understood that sliding device does not necessarily imply that the device slides on another object, but in more general terms a device which is movable in the lateral or transversal direction. The sliding device could thus also be called a lateral movement device.

The invention is based on the insight that the vertical height of the current collector may be substantially reduced when not in use by making the contact element, or current collector as a whole, rotatable around an additional axis of rotation, and in particular rotatable or foldable in a sideways/upwards (lateral/vertical) direction towards the underside of the vehicle, and vice versa when electrical feeding is to start. Put differently, the invention is based on the insight that the vertical height may be reduced by making the contact element, or the current collector as a whole, rotatable not only backwards/upwards (longitudinally/vertically) but also sideways/upwards (laterally/vertically), which in general terms may be described as rotatable around two non-parallel axes of rotation, and two perpendicular axes of rotation in particular. In this manner, the current collector, having a contact element which must have a certain vertical extension to be able to extend into the groove of the rail element to make contact with its conductor(s), can be folded in two directions to substantially reduce its height.

In embodiments, the rotational axis is substantially parallel with a longitudinal direction of the vehicle. In such embodiments, the current collector is advantageously disposed substantially in abutment or substantially parallel with the underside of the vehicle in the folded-up position. The contact element, or the current collector as a whole, may furthermore be disposed substantially horizontally in the folded-up position. In other embodiments, the rotational axis and a longitudinal direction of the vehicle forms an angle of less than 10 degrees. In such embodiments, the current collector or the contact element thereof may be almost horizontal or parallel within the underside of the vehicle.

In embodiments, the current collector has a height of less than 30 mm, preferably less than 20 mm, in the folded-up or raised position.

In embodiments, the current collector comprises at least one collector arm, each having a first end portion being rotatably attached to the sliding device to rotate around the rotational axis, and a second end portion to which the contact element is connected. The at least one contact element may be vertically displaceable by means of the collector arm being a telescopic arm. Alternatively, the at least one contact element may be vertically displaceable by means of the first end portion of each contact element further being rotatable around an additional rotational axis disposed at an angle relative to the rotational axis, which additional rotational axis is advantageously perpendicular to the rotational axis. Furthermore, the current collector may comprise two collector arms, which may be arranged in parallel, and wherein the second end portions of the two collector arms are rotatably connected to the contact element.

In alternative embodiments, the at least one collector arm may be considered part of the sliding device, where the at least one contact is rotatably connected to the sliding device by being rotatably connected to the second end of the collector arm to rotate around the above described rotational axis. In such an alternative embodiment, the at least one contact element is vertically displaceable relative the vehicle in the folded- down position.

In embodiments, the contact element is rotatable relative the vehicle or relative the sliding device around a second additional axis which forms an angle with the rotational axis, which second additional axis preferably is a substantially lateral axis. The rotation around a substantially lateral axis may be provided by means of at least one of said two collector arms having a variable length, or by means of the two collector arms being rotatably connected to the sliding device with a variable distance therebetween, for instance by one of the collector arms being connected to the sliding device by means of a pin at the first end portion being slidably arranged in slit, slot or elongated hole. Such embodiments are advantageous since the minimum vertical height in the folded-down position may be reduced.

In embodiments, the sliding device is laterally movable by being attached to a first end of at least one elongated arm extending along an underside of the vehicle, wherein a second end of the at least one elongated arm is rotatably attached to the vehicle around a rotational axis, preferably a vertical rotational axis. Preferably, two elongated arms are provided in parallel and rotatably connected at both ends to the sliding device and the vehicle, such that the sliding device is maintained in parallel with the vehicle at all times. A lateral support member may be provided at an underside of the vehicle in sliding engagement with the sliding device and/or said second end to provide vertical support thereto, for instance by being arranged beneath the sliding device and/or the second end. Furthermore, at least one electrical cable may be disposed along the length of one or more elongated arm to connect the contact element(s) electrically to the vehicle. Furthermore, various means for laterally displacing the sliding device may be provided such as one or more laterally extending wires driven by one or more electrical motors, which wire(s) are connected to the sliding device to provide lateral displacement. Furthermore, a protective cover may be arranged beneath the at least one elongated arm to protect the elongated arm(s), and optionally also the cable(s) and/or wire(s) and/or parts of the sliding device.

In alternative embodiments, the sliding device is laterally movable by being slidably arranged on a laterally extending bar or rail.

In embodiments, the vehicle/arrangement/system further comprises means for generating a magnetic field and means for sensing a variation of a generated magnetic field, the means for generating and the means for sensing being attached directly or indirectly to the sliding device, wherein the means for sensing is configured to generate a signal correlated to a horizontal distance between the means for generating a magnetic field and metal parts of the rail element, wherein the sliding device and/or current collector is/are provided with actuating means configured to, in response to the signal, displace the sliding device in the lateral direction to allow contact with the rail element, and to displace the current collector to the folded-down position and to lower the current collector, by rotations around the rotational and/or additional rotational axes, to make contact with the rail element while moving the sliding device laterally until the contact element(s) slide(s) into the groove(s). The means for generating and sensing a magnetic field may comprise coils as described in applicants’ own patent EP2552735. In other embodiments, one or more optical sensors are provided, which is/are configured to generate a signal corresponding to the horizontal distance between the sliding device and the rail element and/or a discrete signal indicating if the sliding device is laterally aligned with the rail element or not.

According to a fourth aspect of the invention, a method for providing an electrical connection between a current collector of an electrically propellable vehicle and a rail element being located in a road section on which the vehicle is adapted to travel, the rail element comprising at least one electric conductor arranged in at least one groove in the rail element and being adapted to be put under voltage for supplying electric power to the vehicle, wherein the current collector comprises at least one contact element, each contact element being adapted to connect mechanically and electrically with a corresponding contact portion of the at least one electric conductor. The method comprises displacing the current collector in a lateral direction of the vehicle to laterally align the current collector with the rail element, rotating the current collector in a downwards and lateral direction from a folded-up position where the contact element is substantially in abutment with an underside of the vehicle to a folded-down position where the contact element is disposed vertically, and displacing the contact element vertically to make contact with the corresponding contact portion.

The features of the embodiments described above are combinable in any practically realizable way to form embodiments having combinations of these features. Further, all features and advantages of embodiments described above with reference to the first, second and third aspects of the invention may be applied in corresponding embodiments of the fourth aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

Above discussed and other aspects of the present invention will now be described in more detail using the appended drawings, which show presently preferred embodiments of the invention, wherein: fig. 1 shows a top view of parts of an embodiment of an arrangement, vehicle or system according to the first, second and third aspects of the invention where the current collectors are in folded-up position; fig. 2 shows a top view of the embodiment in fig. 1 , with the current collectors in a folded-down position; fig. 3 shows a cross-section view of the embodiment in figs. 1-2 shown with a rail element, where the current collectors are in a folded-up position; fig. 4 shows a cross-section view of the same embodiment and rail element as in fig. 3, but with the current collectors in a folded-down position; fig. 5 shows the cross-section view as in fig. 4, but with the contact elements of the current collectors in contact with the rail element; fig. 6 shows a side view of another embodiment of parts of an arrangement, vehicle or system according to the first, second and third aspects of the invention; fig. 7 shows a side view of yet another embodiment of parts of an arrangement, vehicle or system according to the first, second and third aspects of the invention; fig. 8 shows a plane view from below of an electrically propellable vehicle according to the first aspect of the invention, which embodiment comprises a current collector as shown in figs. 1-5, and fig. 9 shows a flow-chart illustrating an embodiment of a method according to the fourth aspect of the invention.

DETAILED DESCRIPTION

Fig. 1 shows a top view of parts of an embodiment of an arrangement, vehicle or system according to the first, second and third aspects of the invention where the current collectors are in folded-up position. Two current collectors 2a, 2b are shown each comprising a contact element 6a, 6b, each contact element being adapted to connect mechanically and electrically with a corresponding contact portion of an electric conductor arranged in a groove in a rail element being located in a road section on which the vehicle is adapted to travel (see fig. 3-5). A sliding device 7 is displaceable in a lateral direction of the vehicle (ref. 17, see fig. 8), i.e. a transversal direction relative a direction of travel along a lateral support member 15 provided at an underside of the vehicle, which also provides vertical support for the sliding device. The lateral movement of sliding device 7 is further explained below with reference to fig. 8. The current collector 2a comprises collector arms 9a’, 9a” arranged in parallel and rotatably connected at first ends thereof around rotation points or axes 10a’, 10a” to the sliding device, and rotatably connected at seconds ends thereof to the contact element 6a. The current collector 2b comprises collector arms 9b’, 9b” in a corresponding manner. The current collectors 2a, 2b are furthermore rotatable around rotational axes 8a, 8b by means of the connections at 10a’, 10a”, 10b’, 10b” being made to hinge portions of the sliding device 7 being foldable or rotatable around the rotational axes 8a, 8b relative the rest of the sliding device. In this embodiment, the rotational axes are parallel with a longitudinal or lengthwise direction of the vehicle. In fig. 1 , the current collectors are shown in a folded-up or raised position where the current collectors are disposed in a horizontal plane (see also fig. 3). Depending on the vehicle, the current collectors may be arranged in parallel with the floor pane/underside of the vehicle in this position, or even in abutment with the underside of the vehicle. The contact elements may furthermore be displaceable in the horizontal plane forwards or backwards relative the position shown in fig. 1 to reduce the lateral or longitudinal extension, if required. In this position, the current collector has a height of less than 20 mm.

Fig. 2 shows a top view of the embodiment in fig. 1 , with the current collectors 2a, 2b in folded-down or lowered positions. As can be seen in the figure, the collector arms and the contact elements 6a, 6b are vertically disposed, i.e. disposed in respective vertical planes. The contact elements 6a, 6b of the current collectors are vertically displaceable relative the sliding device in the folded-down position by rotating the collector arms 9a’, 9a”, 9b’, 9b” around connections 10a’, 10a”, 10b’, 10b”.

Fig. 3 shows a cross-section view of the embodiment in figs. 1-2 shown with a rail element 3, where the shown current collector 2b is in a folded-up position, i.e. the same position as shown in fig. 1 . The rail element 3, shown in cross section along a center line or longitudinal axis thereof, comprises an electric conductor 4 having a contact portion 4’ arranged in a groove 5 of the rail element. Fig. 4 shows a cross-section view of the same embodiment and rail element as in fig. 3, but with the current collectors in a folded-down position, i.e. after the current collector 2b has been rotated 90 degrees around rotational axis 8b (see fig. 1 ) relative the sliding device 7. The collector arms 9b’, 9b” are in abutment with each other, illustrating the highest possible vertical position of the contact element 6b in the folded-down position, where the contact element 6b is disposed above ground and above the rail element to allow the sliding device 7 to move in the lateral direction.

Fig. 5 shows the cross-section view as in fig. 4, but with the contact element 6b of the current collector 2b vertically lowered into the groove 5 of the rail element 4 such that the contact element makes electrical and mechanical contact with the contact portion 4’ of the electric conductor 4. It is understood that the vertical alignment of the contact element 6b is appropriate to allow the contact element to be lowered into the (vertical) groove of the rail element.

Fig. 6 shows a side view of another embodiment of parts of an arrangement, vehicle or system according to the first, second and third aspects of the invention. Just like the embodiment in figures 1-5, it comprises a laterally movable sliding device 107 and a current collector 102 comprising collector arms 109’, 109” rotatable around a rotational axis parallel with the longitudinal direction of the vehicle and around additional rotational axes defined by respective connections 110’, 110”, and a contact element 106 to which opposite ends of the collector arms are rotatably attached. This embodiment differs from the embodiment in figures 1-5 in that the contact element 106 is rotatable relative the vehicle or relative the sliding device around a second additional axis coinciding with the attachment 111 of the collector arm 109” to the contact element. The second additional rotational axis is parallel with the additional rotational axis and is thus also a lateral axis. This rotation is achieved since the collector arm 109’ is a telescopic arm, thus having a variable length. Compared to the embodiment in figures 1-5, the minimum vertical height in the folded-down position is reduced.

Fig. 7 shows a side view of yet another embodiment of parts of an arrangement, vehicle or system according to the first, second and third aspects of the invention. This embodiment corresponds to the embodiment in figure 6, except for that both collector arms 209’, 209” of the current collector 202 are fixed in length, and in that the sliding device 207 is provided with an elongated hole or slit 212 in which a pin-shaped portion of the rotational connection 210’ of collector arm 209’ is slidably disposed to allow rotation of contact element 206 around attachment 211 . Compared to the embodiment in figures 1-5, the minimum vertical height in the folded-down position is reduced.

Fig. 8 shows a plane view from below of an electrically propellable vehicle 1 according to the first aspect of the invention, which embodiment comprises current collectors 2a, 2b as shown in figs. 1-5. The sliding device 7 is laterally movable along arc-shaped lateral support member 15 (not seen in this view, but illustrated with dotted lines) by being rotatably attached to to first ends 13a”, 13b” of two parallel elongated arms 13a, 13b extending along an underside of the vehicle, wherein second ends 13a’, 13b’ of the arms are rotatably attached to the vehicle around a vertical rotational axis 14. Since the arms are parallel, the sliding device is maintained in parallel with the vehicle at all times. Two electrical cables are disposed along the length of the arms 13a, 13b and connect the contact elements 2a, 2b electrically to the vehicle. A protective cover 16 (not seen in this view, but illustrated with dotted lines) is arranged beneath the arms 13a, 13b to protect the arms, the cables and the lateral support member 15.

Furthermore, although not illustrated in the figures above, the vehicle/arrangement/system further comprises means for positioning the sliding device laterally, for instance as described in EP2552735, and further in the summary section above. Furthermore, it is understood that the sliding device and/or the current collectors is/are provided with position sensors and actuators, which may be of electric, hydraulic or pneumatic type, to provide the above described rotations and displacements of the contact elements. Such sensors and actuators are considered known to the person skilled in the art and are thus not further explained herein.

Fig. 9 shows a flow-chart illustrating an embodiment of a method according to the fourth aspect of the invention. The method comprises displacing 301 the current collector in a lateral direction of the vehicle to laterally align the current collector with the rail element, rotating 302 the current collector in a downwards and lateral direction from a folded-up position where the contact element is substantially horizontal and/or in abutment with an underside of the vehicle to a folded-down position where the contact element is disposed vertically, and displacing 303 the contact element vertically to make contact with a corresponding contact portion of the electric conductor in the rail element.

The description above and the appended drawings are to be considered as non limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention.

For example, the current collector does not necessarily need to have the shown “plow shape” but may for instance be round to rotate against a bottom contact portion or vertical side wall contact portion of the electric conductor, or any other shape which is suitable for achieving the desired electric contact. Furthermore, the current collector does not necessarily need to have two collector arms, but may for instance have only one collector arm. Furthermore, the current collector does not necessarily need to be rotatable relative the sliding device around the rotational axis by means of a hinge, but may for instance be achieved using an axle and bearing arrangement or any other suitable device to provide such rotation.