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Title:
HOUSING AND SYSTEM FOR ELECTRIC ROADS
Document Type and Number:
WIPO Patent Application WO/2016/023705
Kind Code:
A1
Abstract:
This application discloses an elongated housing (20) for an electric road system, the housing (20) being intended to be positioned on top of a road surface (11), wherein the housing (20) comprises, as seen in a cross-section, a top section having: a mid portion (21, 41a, 41b, 41c, 41d) being elevated in view of the road surface (11), the mid portion (21, 41a, 41b, 41c, 41d) forming a top recess with an opening for receiving a conductive rail segment (30, 30a, 30b), wherein the opening is arranged to be facing away from the road surface (11); and inclined side portions (22, 42a, 42b, 42c, 42d) extending outwards from opposite sides of the opening and towards the road surface (11); wherein the top section is arranged to be grounded. The application also relates to an electric road system comprising an elongated housing (20), conductive rail segments (30, 30a, 30b) and a power supply assembly.

Inventors:
ZETHRAEUS DAN (SE)
Application Number:
PCT/EP2015/066394
Publication Date:
February 18, 2016
Filing Date:
July 17, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ZETHRAEUS DAN (SE)
International Classes:
B60L5/04; B60L5/38; B60M1/30
Foreign References:
US6230861B12001-05-15
US5045646A1991-09-03
GB2084096A1982-04-07
Attorney, Agent or Firm:
AWAPATENT AB (Helsingborg, SE)
Download PDF:
Claims:
CLAIMS

1 . An elongated housing for an electric road system, the housing being

intended to be positioned on top of a road surface (1 1 ), wherein the housing comprises, as seen in a cross-section, a top section having:

a mid portion (21 , 41 a, 41 b, 41 c, 41 d) being elevated in view of the road surface (1 1 ), the mid portion (21 , 41 a, 41 b, 41 c, 41 d) forming a top recess with an opening for receiving a conductive rail segment (30, 30a, 30b), wherein the opening is arranged to be facing away from the road surface (1 1 ); and

inclined side portions (22, 42a, 42b, 42c, 42d) extending outwards from opposite sides of the opening and towards the road surface (1 1 );

2. The elongated housing according to claim 1 , wherein the top section is arranged to be grounded.

3. The elongated housing according to claim 1 or 2, wherein at least one of the inclined side portions (22, 42a, 42b, 42c, 42d) together with a side wall portion (23, 43a, 43b, 43c, 43d) of the top section form a bottom recess with an opening arranged to be facing towards the road surface (1 1 ).

4. The elongated housing according to any one of claims 1 -3 wherein the housing further comprises a bottom section (25, 45b, 45c, 45d) arranged to be facing the road surface (1 1 ), the bottom section (25, 45b, 45c, 45d) extending at least partly along the width of the housing.

5. The elongated housing according to claim 3 or 4, further comprising

spacing elements (70) arranged to be located between the bottom section (25, 45b, 45c, 45d) and the road surface (1 1 ), wherein the spacing elements (70) are spaced apart from each other so as to allow rain water to flow past the housing between the bottom section (25, 45b, 45c, 45d) and the road surface (1 1 ).

6. The elongated housing according to any one of claims 1 -5, the housing further comprising an electrically isolating top surface layer (26) arranged on top of each of the inclined side portions (22), the electrically isolating top surface layer (26) being arranged to prevent conductive contact between ambient objects and the inclined side portions (22).

The elongated housing according to claim 6, further comprising:

a ground strip (28) arranged on top of each of the electrically isolating top surface layers (26);

wherein each ground strip (28) extends along the elongation direction of the housing; and

wherein each ground strip (28) is conductively connected to the top section of the housing such that the ground strip (28) is grounded.

The elongated housing according to any one of claims 1 -7, wherein the inclined side portions (22, 42a, 42b, 42c, 42d) extend to the road surface (1 1 ), thereby being arranged to provide a transition portion, between the road surface (1 1 ) and the conductive rail segment (30, 30a, 30b) arranged in the top recess, for a vehicle passing over the housing.

An electric road system comprising:

an elongated housing (20) intended to be positioned on top of a road surface (1 1 ), the housing (20) comprising, as seen in a cross-section, a top section having a mid portion (21 , 41 a, 41 b, 41 c, 41 d) being elevated in view of the road surface (1 1 ), the mid portion (21 , 41 a, 41 b, 41 c, 41 d) forming a top recess with an opening arranged to be facing away from the road surface (1 1 ), and inclined side portions (22, 42a, 42b, 42c, 42d) extending outwards from opposite sides of the opening towards the road surface (1 1 );

conductive rail segments (30, 30a, 30b) arranged consecutively in the top recess of the housing (20), thereby forming a single segmented rail; and

a power supply assembly arranged to power every other conductive rail segment (30a) separately.

10. The electric road system according to claim 9, wherein the power supply assembly is positioned between one of the inclined side portions (22) and the road surface (1 1 ).

1 1 .The electric road system according to claim 10, wherein the power supply assembly comprises a positive terminal element (18) and a negative terminal element (19), and wherein the negative terminal element (19) is arranged between the positive terminal element (18) and the inclined side portion (22) such that physical contact between the positive terminal element (18) and the housing (20) is prevented. 12. The electric road system according to any one of claims 9-1 1 , further comprising a power supply controller which is located in an inner space of each conductive rail segment (30a) that is arranged to be powered by the power supply assembly, wherein the power supply controller is adapted to activate and deactivate the power supply to the conductive rail segment (30a).

13. The electric road system according to claim 12, further comprising one or more vehicle sensors, wherein each power supply controller is coupled to one of the vehicle sensors, and wherein each power supply controller is arranged to activate the power supply as a response to a vehicle being sensed by the vehicle sensor coupled thereto.

14. The electric road system according to claim 13, further comprising an electrically isolating member (17) arranged between each adjacent pair of conductive rail segments (30a, 30b), wherein each of the vehicle sensors is arranged in an inner space of an electrically isolating member (17) arranged between the conductive rail segment (30a), which houses the power supply controller coupled to the vehicle sensor, and the closest preceding conductive rail segment (30b).

Description:
HOUSING AND SYSTEM FOR ELECTRIC ROADS

Technical field

The present application relates to the field of power supply to electric vehicles, and in particular to the field of electric road systems.

Background of the invention

Electric vehicles, such as electric cars, are increasingly popular. The motor of the vehicle is powered by the battery when in use. Typically, an electrical vehicle comprises a battery which is charged when the vehicle is parked in for instance a parking lot or at home. A problem with this approach is that large and heavy batteries are needed in order to provide a long running time and the charging at a stationary loading station may be lengthy.

A solution to the above problem is to power the electric vehicle while driving on a road. A common name for systems which provides such powering is electric road systems.

There exist different types of electric road systems. As an example, patent document US 201 1/0266108 discloses an electric vehicle

transportation system using a single-rail system, where a top-rail is connected to an enclosure rail.

Common for this and other known solutions is that the road needs to be reconstructed to a great extent when installing the power track in the road. Reconstruction could for example include cutting up a groove in the road surface, so that the power track can engage with the road surface.

Another drawback with known solutions is that many of the known power collectors to be arranged on the vehicle need careful positioning in order to connect to the power track. The power collector could be a vertical stick which is to be arranged in a groove of the power track. These types of collectors do not allow any significant deviation from the track in order to stay powered. Alternatively, complex power collectors exist for detecting the power track and follow it by use of advanced feedback control systems.

Thus, there is an evident need for improving known electric road systems. Summary of the invention

An object of the present invention is to alleviate the above mentioned drawbacks and problems. A further object is to provide an improved construction of the electric road system in order to facilitate the installation of the system on a road.

According to a first aspect of the invention, this and other objects are achieved by an elongated housing for an electric road system. The housing is intended to be positioned on top of a road surface. The housing comprises, as seen in a cross-section, a top section having a mid portion being elevated in view of the road surface, the mid portion forming a top recess with an opening for receiving a conductive rail segment. The opening is arranged to be facing away from the road surface. The top section further comprises inclined side portions extending outwards from opposite sides of the opening and towards the road surface.

The housing is intended to be a part of an electric road track of an electric road system. An important advantage of the electric road system, and in particular of the electric road track, is that the need for reconstruction of the road surface in order to mount the electric road system is at least reduced in comparison to known systems. The electric road track comprising the housing is arranged on top of the road surface in order to minimize the need for reconstruction of the road surface. Reconstruction could include cutting a groove for housing the electric road track or parts thereof. By reducing the need for engagement with the road, the mounting process becomes easier, less time-consuming and more cost-efficient. The electric road system according to the invention may reduce the installation time and thereby cause less traffic disturbances during installation. Moreover, the electric road track with the housing can be removed from the road surface with only a small or no need for restoration of the road surface. The electric road track can also be located on a road portion, such as on a bridge, where it is not safe or allowed to for example provide a groove in the road surface. A key aspect for achieving the feature of small or no reconstruction of the road surface is the construction of the housing. The housing provides a top recess in which the conductive rail segment can be provided. The housing elevates the conductive rail segment thus enabling easy access for a power collector of a vehicle. By the inclined side portions, a smooth transition between the road surface and the conductive rail segment may be enabled. The construction enables a good balance between elevating the conductive rail segment and minimizing disturbances for vehicles that passes over the housing.

Moreover, by that the mid portion is elevated, a gap between the inclined side portions and the road surface is provided. Parts of the electric road track, such as a power supply assembly, electrical arrangements, connecting means, etc, can be arranged in a protected manner within this gap. The need for lowering these parts into the road under the road surface or for providing a separate housing for these parts is therefore at least reduced. Thus, the need for engagement with the road surface is at least reduced.

At least one of the inclined side portions together with a side wall portion of the top section may form a bottom recess with an opening arranged to be facing towards the road surface.

The top section may be arranged to be grounded.

The housing may comprises a bottom section arranged to be facing the road surface, wherein the bottom section extends at least partly along the width of the housing.

The housing may comprise spacing elements arranged to be located between the bottom section and the road surface. The spacing elements may be spaced apart from each other. The spacing elements enable rain water to flow past the housing between the bottom section and the road surface.

Flooding of the road and of the top of the housing is thereby counteracted.

The housing may comprise an electrically isolating top surface layer arranged on top of each of the inclined side portions. The electrically isolating top surface layer may be arranged to prevent conductive contact between ambient objects and the inclined side portions. The electrically isolating top surface layer prevents both physical and conductive contact between surrounding objects and people and the inclined plates.

The housing may comprise a ground strip arranged on top of each of the electrically isolating top surface layers. Each ground strip may extend along the elongation direction of the housing. Each ground strip may be conductively connected to the top section of the housing such that the ground strip is grounded. This construction is useful in the situation where a layer of conductive material, such as a layer of snow, salt and/or water, is located on the housing and is in contact with the conductive rail segment to which a positive voltage is applied. The conductive layer of material may then form a conductor extending towards the road surface and possible farther away. If for example a person steps in the layer of conductive material, there is a risk that that person is exposed to the voltage. This risk is at least reduced by the ground strips.

The inclined side portions may extend to the road surface, thereby being arranged to provide a transition portion, between the road surface and the conductive rail segment arranged in the top recess, for a vehicle passing over the housing.

According to a second aspect of the invention, the above mentioned and other objects are achieved by an electric road system comprising an elongated housing intended to be positioned on top of a road surface. The housing comprises, as seen in a cross-section, a top section having a mid portion being elevated in view of the road surface, the mid portion forming a top recess with an opening arranged to be facing away from the road surface, and inclined side portions extending outwards from opposite sides of the opening towards the road surface. The electric road system further comprises conductive rail segments arranged consecutively in the top recess of the housing, thereby forming a single segmented rail. The electric road system further comprises a power supply assembly arranged to power every other conductive rail segment separately.

The power supply assembly may be positioned between one of the inclined side portions and the road surface.

In one embodiment, the power supply assembly comprises a positive terminal element and a negative terminal element. The negative terminal element may be arranged between the positive terminal element and the inclined side portion. Physical contact between the positive terminal element and the inclined side portion may thereby be prevented. An advantage with this configuration is that if the side portion is removed or damaged such that the recess underneath is exposed, the positive terminal element is not exposed since it is covered by the negative terminal element . Thus, the risk that a person or an object gets in contact with the positive terminal element, and thereby risks to be exposed to high voltages, is at least reduced. The negative terminal may have the same potential as the ground.

The electric road system may further comprise a power supply controller which is located in an inner space of each conductive rail segment that is arranged to be powered by the power supply assembly. The power supply controller may be adapted to activate and deactivate the power supply to the conductive rail segment. By that the power supply may be activated and deactivated in order to apply voltage to the conductive rail segment only when a vehicle is passing over it, safety for surrounding objects and people is increased.

The electric road system may comprise one or more vehicle sensors. Each power supply controller may be coupled to one of the vehicle sensors. Each power supply controller may be arranged to activate the power supply as a response to a vehicle being sensed by the vehicle sensor coupled thereto.

The electric road system may comprise an electrically isolating member arranged between each adjacent pair of conductive rail segments. Each of the vehicle sensors may be arranged in an inner space of an electrically isolating member arranged between the conductive rail segment, which houses the power supply controller coupled to the vehicle sensor, and the closest preceding conductive rail segment.

The above disclosed features and corresponding advantages of the first aspect is also applicable to this second aspect. To avoid undue repetition, reference is made to the discussion above.

It is noted that the invention relates to all possible combinations of features recited in the claims. Brief description of the drawings

This and other aspects of the present invention will now be described in more detail, with reference to the enclosed drawings showing embodiments of the invention.

Figure 1 is a view from above of a car driving along road provided with an electric road system according to an embodiment of the invention.

Figure 2 is a perspective view of an electric road track with a housing according to an embodiment of the invention.

Figure 3 is a cross-sectional view of the electric road track in Figure 2. Figures 4a-4d are schematic views of cross-sections of different top sections and bottom sections according to embodiments of the invention.

Figure 5 is a schematic view of an electric road track as seen from the side.

Figure 6 is a cross-sectional view of the electric road track in Figure 5 taken at an anchoring section.

Figure 7 is a view from below of the electric road track in Figure 6.

Figure 8 is a perspective view of an electrical isolating member.

Figure 9 is a perspective view of a power collector.

Detailed description of preferred embodiments

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and for fully conveying the scope of the invention to the skilled person.

An electric road system according to an embodiment of the invention is seen from above in Figure 1 . The electric road system is mounted on a road surface 1 1 on which a vehicle, in the form of a car 12, is travelling in the direction indicated by 13. The electric road system comprises an electric road track 10 which extends along the intended travelling path of the road. The general function of the electric road system 10 is that it provides electrical power to vehicles travelling along the road. Thus, the motors of the vehicles can be continuously powered by electricity. Moreover, the battery of the vehicle can be charged while the vehicle is travelling on the road.

For the electric road system according to the invention, this function is achieved by providing power through the electrical road track 10 to which power collectors 14a, 14b, 14c of the car 12 can connect.

The electrical road track 10 forms a single track line comprising conductive rail segments 30a, 30b. The conductive rail segments 30a, 30b are separated along the track line by electrically isolating members 17. Every other conductive rail segment 30a is powered by a power supply assembly arranged within the electric road track 10. The power supply assembly is in turn powered by high power stations 15 which are located at the side of the road and connected to the electrical road track 10 via conductors 16a, 16b. The conductors 16a, 16b may be having different shapes. According to one embodiment the conductors 16a, 16b are in the form of flat sheet shaped conductors. Such flat sheet shaped conductors may e.g. comprise an inner conducting layer made of electrically conductive material, e.g. a metal, with insulating layers surrounding the conducting layer. The insulating layers being made of electrically non-conductive material, e.g. rubber. The flat sheet shaped conductors may further comprise outer grounded layers made of electrically conductive material, e.g. a metal. According to one embodiment such a flat sheet shaped conductor may be 1 -2 cm think and 0.1 -1 m wide.

The powered conductive rail segments 30a form positive poles. The non-powered conductive rail segments 30b may be set to have the same potential as ground. The non-powered conductive rail segments 30b form negative poles. Thus, when the conductive rail segments 30a are powered, a voltage difference is created between the powered conductive rail segments 30a and the non-powered conductive rail segments 30b.

The power collectors 14a, 14b, 14c are arranged such that, at any moment during travelling, at least one of the power collectors 14a, 14b, 14c is in connection with a powered conductive rail segment 30a and at least one other of the power collectors 14a, 14b, 14c is in connection with a non- powered conductive rail segment 30b. Thus, continuous collection of power from the electrical road track 10 is achieved.

The electrical road track 10 is arranged along and essentially in the middle of the road such that the car 12 travels with one side wheel pair on each side of the electrical road track 10. It is appreciated that other positions of the electrical road track 10 is possible depending on its construction and on the construction of the power collectors.

The electrical road track 10 extends 200-500 m along the road. The conductive rail segments 30a, 30b may be around 1 m long. The electrically isolating member 17 may be about 10-30 cm long. A plurality of electrical road tracks 10 can be arranged after each other in order to provide an electrical road system along a longer part of the road. As can be seen in Figure 1 , two electric road tracks 10 are arranged after each other.

The power station 15 is advantageously positioned near a junction between two adjacent electric road tracks 10. Thus, one single power station 15 can without the need for long conductors power adjacent electric road tracks 10 by connecting a conductors 16a, 16b to each of the electric road tracks 10, instead of arranging one power station to each electric road track 10.

The electric road track 10 comprises a housing 20. An important advantage of the electric road system, and in particular of the electric road track 10, is that the need for reconstruction of the road surface 1 1 in order to mount the electric road system is at least reduced in comparison to known systems. The electric road track 10 is arranged on top of the road surface 1 1 in order to minimize the need for reconstruction of the road surface 1 1 .

Reconstruction could include e.g. cutting a groove for housing the electric road track 10 or parts thereof.

By reducing the need for engagement with the road, the mounting process becomes easier, less time-consuming and more cost-efficient. The electric road system according to the invention may reduce the installation time and thereby cause less traffic disturbances during installation. Moreover, the electric road track 10 can be removed from the road surface 1 1 with only a small or no need for restoration of the road surface. The electric road track 10 can also be located on a road portion, such as on a bridge, where it is not safe or allowed to for example provide a groove or the like in the road surface.

A key aspect for achieving the feature of small or no reconstruction of the road surface 1 1 is the construction of the housing 20. Exemplifying embodiments of the housing 20 will now be disclosed in detail with reference to Figures 2-4d.

The housing 20 is illustrated in perspective view in Figure 2. The housing 20 is arranged to receive a conductive rail segment 30 representing any of the conductive rail segments 30a, 30b illustrated in Figure 1 . The housing 20 is arranged to be positioned on top of the road surface 1 1 . The housing 20 elevates the conductive rail segment 30 to make it easily accessible for power collectors of bypassing vehicles and at the same time protect objects and people in the surroundings from the voltage which can be highly dangerous if accessed.

The housing 20 is seen in cross-section in Figure 3. The housing 20 comprises a top section having a mid portion 21 and side portions 22. The mid portion 21 is formed by side walls 23 and a bottom wall 24. The mid portion 21 is elevated in view of the road surface 1 1 . The side walls 23 and the bottom wall 24 of the mid portion 21 form a top recess with an opening for receiving the conductive rail segment 30. The opening faces away from the road surface 1 1 when the housing is positioned thereon.

The side portions 22 are formed by inclined plates 27 which extend outwards from opposite sides of the opening of the mid portion 21 and towards the road surface 1 1 . The inclined plates 27, the side walls 23 and the bottom wall 24 may be made in a metal material such as aluminum.

In this embodiment, the side portions 22 extend all the way to the road surface 1 1 . The side portions 22 thus provides a smooth transport for the wheels of a vehicle passing the housing 20 by that the side portions 22 provides transition portions between the road surface 1 1 and the top of the electric road track 10 formed by the conductive rail segment 30.

The conductive rail segment 30 is arranged in the top recess of the mid portion 21 . The conductive rail segment 30 forms an elongated hollow casing comprising walls 31 which defines an inner space 32. The walls 31 may be made by steel.

The top recess is preferably arranged with a height chosen such that the conductive rail segment 30 extends slightly above, such as by 5 mm, the uppermost point of the surrounding side portions 22. Thus, the power collectors of a bypassing vehicle can slide along the conductive rail segment 30 without making contact with the housing 20.

A bottom recess is defined by each of the side portions 22 together with one of the side walls 23 of the mid portion 21 . The bottom recess has an opening which is arranged to face the road surface 1 1 . The bottom recess is arranged to house one or more terminal elements of a power supply assembly.

In this embodiment, two types of power supply assembly are arranged in each bottom recess: a positive terminal element 18 and a negative terminal element 19. By that terminal elements of different voltage levels are arranged together in one recess, the resulting magnetic field is reduced in comparison to providing one or more terminals having the same voltage level.

The positive terminal element 18 and negative terminal element 19 are formed by solid elongated plate elements. The terminal elements 18, 19 are made in a conductive material such as aluminum. The surface of each terminal element is covered by an electrically isolating material, such as rubber.

The positive terminal element 18 is connected to every other conductive rail segment of the rail segments 30. The rest of the conductive rail segments are connected to the negative terminal element 19 or to another equal negative pole or grounded source. Thus, a voltage difference is provided between adjacent conductive rail segments 30 which can be utilized for generating an electrical current through a power collector of a vehicle.

The positive terminal element 18 is physically separated from the side sections 22 by that the negative terminal element 19 is arranged therebetween. Physical contact between the positive terminal element 18 and the inclined side portion 22 is thus prevented. An advantage with this

configuration is that if the side portion 22 is removed or damaged such that the recess underneath is exposed, the positive terminal element 18 is not exposed since it is covered by the negative terminal element 19. Thus, the risk that a person or an object gets in contact with the positive terminal element 18, and thereby risks to be exposed to high voltages, is at least reduced.

By that the housing 20 provides a bottom recess in which the power supply assembly can be arranged in a protected manner, there is no need for lowering the power supply assembly into the road under the road surface 1 1 or for providing a separate housing for these members. Thus, the need for engagement with the road surface 1 1 is at least reduced. The construction of the housing 20 also benefits from that the power supply assembly is located in the bottom recesses since they function as a support for the side portions 22.

The power supply assembly is externally powered by a power station as previously disclosed. The electrical connection between the terminal elements 18, 19 and the power station 15 is not illustrated in Figure 3. The electrical connection can however be achieved in accordance to known procedures.

In order to protect objects and people in the surroundings from the potentially dangerous voltage, the mid portion 21 and side portions 22 are grounded. By grounded is meant that the mid portion 21 and side portions 22 are connected to an external ground or to at least one of the negative terminal elements 19. The voltage of the negative terminal element 19 or of the mid portion 21 and side portions 22 do not need to be absolute zero. The negative terminal 19 may have a voltage above absolute zero voltage, as long as it is lower than the positive terminal element 18 voltage to a desired level.

The voltage level of the negative terminal element 19 and the portions of the housing 20 may differ in the range of a few volts along the housing 20 which typically has a length of 200-500 m.

The housing 20 may in its longitudinal direction be segmented into a plurality of segments. The longitudinal length of these segments may be in the order of meters to tenths of meters.

In the illustrated embodiment of Figure 3, the housing 20 further comprises a bottom section 25 arranged to face the road surface 1 1 . The bottom section 25 extends across the width of the housing 20. By that the bottom section 25 extends across the opening of the bottom recesses, the power supply assembly is protected from the road surface 1 1 .

The bottom section 25 may be made of the same material as the top section, e.g. a metal such as aluminum. The bottom section 25 may be directly or indirectly connected to the negative terminal element 19 such that the bottom section 25 is grounded. The bottom section 25 may extend along the whole or a part of the length of the housing 20.

The housing 20 comprises an electrically isolating top surface layer 26 arranged on top of each of the inclined side portions 22, i.e. on top of each of the inclined plates 27. Each electrically isolating top surface layer 26 extends along the whole width of the inclined plates 27, and along the whole length of the housing 20. The electrically isolating top surface layer 26 may be made in one piece or comprise a plurality of joint portions. The electrically isolating top surface layer 26 prevents both physical and conductive contact between surrounding objects and people and the inclined plates 27.

The electrically isolating top surface layer 26 is ridged. According to one embodiment the ridges extend in the elongation direction of the housing 20, i.e. in the elongation direction of the electric road track 10. However, the ridges may also be arranged in other patterns, such as a checkered pattern. The ridged pattern provides a good grip for wheels of a vehicle passing over the housing 20. The electrically isolating top surface layer 26 is made in rubber or in another suitable material.

The electrically isolating top surface layer 26 may in other embodiments be a glue or paint material which is applied on the side portions 22 by a brush or similar. Damages in the surface layer may thus be repaired by applying more material instead of replacing portions of or the whole isolating top surface layer 26.

The housing 20 comprises an isolating recess surface layer 29 arranged along the inner surface of the side walls 23 and of the bottom wall 24. The isolating recess surface layer 29 prevents conductive contact between the conductive rail segment 30 and each of the side walls 23 and the bottom wall 24. Alternatively, or additionally, the conductive rail segment 30 may comprise an isolating surface layer arranged to prevent conductive contact with the housing 20. Such a layer would preferably be arranged on every outer surface of the conductive rail segment 30 except for the upper surface with which the power collector makes contact. The material chosen for the isolating layers may be rubber.

The housing 20 comprises a ground strip 28 arranged on top of each of the electrically isolating top surface layers 26. The ground strips 28 extend along the elongation direction of the housing 20. The ground strip 28 is made in a conductive material such as aluminum.

Each of the ground strips 28 is conductively connected to one of the inclined plates 27 of the housing 20 which in turn is connected to one of the negative terminal elements 19 or to a ground source. The ground strips 28 are thus grounded. This construction is useful in the situation where a layer of conductive material, such as layer of snow, salt and or water, is located on the housing 20 and is in contact with one of the conductive rail segments 30 to which a positive voltage is applied. The layer of conductive material may then form a conductor extending towards the road surface 1 1 and possible farther away. If for example a person steps in the layer of conductive material, there is a risk that that person is exposed to the voltage. This risk is at least reduced by the ground strips 28. Any current conducted through the layer of conductive material will be attracted to the negative voltage of the ground strip 28, and thus the possibility of currents farther outward in the layer of conductive material is counteracted. Moreover, an earth leakage circuit breaker (not shown) may be arranged to sense a current in the ground strip 28 and deactivate the power to the positive terminal element 18.

The dimensions of the housing 20 will now be discussed. It is

appreciated that the disclosed dimensions provide only one of many example of how the housing may be dimensioned.

The mid portion 21 is positioned in the center of the housing 20 as seen in its cross-section. Each of the side portions 22 extends outward and contributes to width W of the housing 20 as measured from the center of the mid portion 21 to the outer end of the side portion 22. The housing 20 has a height H as measured from the road surface 1 1 to the uppermost portion of the housing 20 when the housing 20 is arranged on the road surface 1 1 .

The height H is preferably 10-15 % of the total width of the housing 20. The total width is two times the width W in Figure 3. It has been found that a ratio between the height H and the total width within the interval of 10-15 % provides a good balance between elevating the conductive rail segment, such that it is easily accessible to a power collector, and minimizing disturbances for vehicles that passes over the housing 20.

An upper limit for the height H, assuming that the conductive rail segment 30 protrudes only slightly above the housing 20, is defined by the lowest clearance between the road surface 1 1 and a chassis of a bypassing vehicle. The height H should preferably not exceed 1/3 of the lowest clearance. Depending on which types of vehicles the road is intended for, the clearance could be different for different housings 20. A common clearance for a passenger car is in the range of 14 cm .

Figures 4a-4d illustrates examples of possible configurations of housings according to embodiments of the invention. The housings are seen in cross-section.

As realized by the skilled person, a housing according to the invention may take many different forms, not only the exemplified ones, while still providing the intended functions, i.e. to provide a safe housing for an electric road track which requires small or no reconstruction of the road.

Figure 4a illustrates a housing 40a with a top section. The top section has a mid portion 41 a and inclined side portions 42a. The mid portion 41 a is formed by side walls 43a and a bottom wall 44a. The side walls 43a and the bottom wall 44a form a top recess with an opening which is intended to face away from a surface of a road when the housing 40a is placed on the road.

An electric road track can be assembled by arranging a power supply assembly on the surface of the road or on a suitable material provided thereon, and thereafter arranging the housing 40a on top such that terminal elements of the power supply assembly is received in bottom recesses of the housing 40a. The bottom recesses are formed by each adjacent pair of side wall 43a and inclined side portion 42a. Conductive rail segments can thereafter be arranged in the top recess of the housing 40a. Necessary conductive connection between e.g. the conductive rail segments and the power supply assembly can thereafter be made.

The top section can be formed in one piece, such as by plate bending. Figure 4b illustrates a housing 40b which has a top section comprising a mid portion 41 b and inclined side portions 42b. The housing 40b further comprises a bottom section 45b. The bottom section 45b extends along the whole width of the housing 40b. Side walls 43b of the mid portion 41 b form a top recess. The top recess has an opening which faces away from the surface of the road when the housing 40b is positioned with its bottom section 45b on the road surface. The top recess has an additional opening with faces towards the surface of the road. The additional opening is covered by the bottom section 45b.

The top section, with its mid portion 41 b and inclined side portions 42b, and the bottom section 45b can be formed in one piece, such as by plate bending.

Figure 4c illustrates a housing 40c which has a top section comprising a mid portion 41 c and inclined side portions 42c. The housing 40c further comprises a bottom section 45c. The bottom section 45c extends along the whole width of the housing 40c. Side walls 43c and a bottom wall 44c of the mid portion 41 c form a top recess. The top recess has an opening which faces away from the surface of the road when the housing 40c is positioned with its bottom section 45c on the road surface.

The housing 40c is arranged such that a gap between the bottom wall 44c and the bottom section 45c is formed. The gap can house for example electrical connection members connecting the top section with a negative terminal element or connecting a conductive rail segment arranged in the top recess with a positive terminal element.

Yet another example of a housing 40d is illustrated in Figure 4d. The housing 40d comprises a top section which has a mid portion 41 d and inclined side portions 42d. The mid portion 41 d is provided with a top recess which is formed by side walls 43d and a bottom wall 44d. The housing 40d further comprises a pair of bottom sections 45d. Each bottom section 45d extends across an opening of a bottom recess which is formed by each of the inclined side portions 42d and its adjacent side wall 43d. Thus, the bottom sections 45d, the inclined side portions 42d and the side walls 43d form a pair of casings with a triangular cross-section. The bottom wall 44d connects the side walls 43d of the casings. Each of the casing and the bottom wall 44d can be pre-manufactured and transported separately, and assembled to form the housing 40d directly on a road. Thus, the embodiment of Figure 4d provides a space-efficient solution with respect to manufacturing of the housing.

The housings 40a, 40b, 40c, 40d illustrated in Figure 4a-4d may comprise construction details such as ground strips and electrically isolating layers as disclosed in connection to Figure 3.

An embodiment of an electric road track 50 mounted on a road surface 1 1 is seen from the side in Figure 5. The electric road track 50 comprises a housing 20, conductive rail segments 30a, 30b, and electrically isolating members 17. These parts have similar construction to those previously disclosed.

The electric road track 50 is mounted to the road by means of anchoring sections 60. The anchoring sections 60 are arranged at a mutual distance of 1 -3 m as seen in the extension direction of the electric road track 50. The construction of the anchoring section 60 is illustrated in Figures 6 and 7. In Figure 6, the electric road track 50 is illustrated in cross-section taken at one of the anchoring sections 60.

The anchoring section 60 comprises a connection plate 61 and a bottom plate 62. The connection plate 61 is attached to an underside of a bottom section 25 of the housing 20 by means of conventional attachment means such as screws. The bottom plate 62 may be attached to the road surface 1 1 by means of attachment means such as an adhesive or by screws.

The bottom plate 62 is provided with apertures 63 as illustrated in Figure 7. An adhesive provided as attachment means between the road surface 1 1 and the bottom plate 62 can penetrate the apertures 63 in order to strengthen the attachment. An adhesive with a suitable softness should be chosen in order to absorb impact forces when a vehicle passes over the housing 20. The bottom plate 62 is formed as a U-shaped profile with its side walls bent inwards, similar to the shape of a staple. The bottom plate 62 is arranged to receive the connection plate 61 by sliding the connection plate 61 in the extension direction of the housing 20 such that the bottom plate 62 grasps side portions of the connection plate 61 . The connection plate 61 is thereby fixed sideways but is still allowed to move (by sliding) in the extension direction of the housing 20. This allow for housing extension variation due to temperature differences. The bottom plate 62 may be arranged so as to allow the connection plate 61 to move slightly sideways in order to permit small deviation in the alignment of the bottom plates 62 along the electric road track 50. By providing a gap between the bottom plate 62 and the connection plate 61 , the materials is also allowed to expand due to temperature variations.

The construction of the anchoring sections 60 enables easy mounting and removal of the housing 20 on the road surface 1 1 . For example, if the electric road track 50 needs to be removed for maintenance or replacement, it can easily be disconnected from the bottom plates 62 by sliding off the connection plates 61 in the extension direction of the housing 20 and of the electric road track 50. There is no need for detaching any screws or fastening means between the housing 20 and the road surface 1 1 , which can

potentially cause damage to the road surface 1 1 .

Returning to Figure 5, spacing elements 70 are arranged between the bottom section (not indicated) of the housing 20 and the road surface 1 1 . The spacing elements 70 are spaced apart from each other in the extension direction of the electric road track 50. The spacing elements 70 may for example comprise bars which extend transverse the extension direction of the electric road track 50. The bars may extend along the whole width of the housing 20 or along a part thereof. The spacing elements 70 may form part of the housing 20 or form separate elements which are mounted when the electric road track 50 is assembled and mounted to the road surface 1 1 .

The spacing elements 70 distance the bottom section of the housing 20 from the road surface 1 1 . Road surfaces are often sloped towards the sides of the road so that rain water is led away from the road surface 1 1 . By the spacing elements 70, the rain water is allowed to flow past the housing 20 between the bottom section and the road surface 1 1 . Flooding of the road and of the top of the housing 20 is thereby counteracted.

An embodiment of the electrically isolating member 17 in Figure 1 will now be disclosed with reference to Figure 1 and Figure 8. The electrically isolating member 17 comprises a first part 81 a and a second part 81 b. Each part comprises a contact portion 82a, 82b. The electrically isolating member 17 is arranged between two conductive rail segments 30a, 30b. The contact portions 82a, 82b are inserted into the inner spaces of the conductive rail segments 30a, 30b through open ends of the rail segments 30a, 30b.

The electrically isolating member 17 may be attached to a bottom section or to a bottom wall of the housing 20, or to a connection plate of an anchoring section, such as to the connection plate 61 in Figures 5-7. A screw hole 83 is provided in each of the first and second parts 81 a, 81 b through which a screw can be inserted for providing the attachment.

The first part 81 a and second part 81 b are arranged next to each other so as to form a single unit. The joint 84 between the first and second parts 81 a, 81 b is tilted in view of the extension direction of the electrically isolating member 17. The tilting provides a smooth transition for a power collector led over the joint 84 in the extension direction of the electrically isolating member 17, when compared to a joint extending perpendicular to the extension direction.

An example of a power collector part 90 which can be used in

combination with electric road systems disclosed in this application is illustrated in Figure 9. The power collector part 90 is intended to be mounted to a chassis of a vehicle. The power collector part 90 comprises a U-shaped bar 92 which is connected to the vehicle at its upper side. A pair of legs 91 is connected to the lower side of the bar 92. The legs 91 are angled backwards, in view of the travelling direction of the vehicle, by 20-45 degrees. The backward angle provides the advantage that a larger contact surface between the legs 91 and the conductive rail segments of the electric road track is enabled. Moreover, vibrations and other disturbances when the pair of legs 91 travels over a joint in the electric road track may be reduced. The length of the legs 91 is preferably as long as possible without protruding from the vehicle. In other words, the total length of the pair of legs 91 is preferably near the vehicle's width. The driver of the vehicle is thus provided with a large freedom to move the vehicle sideways as long as the vehicle has one side wheel pair on each side of the electric road track.

A power collector comprises at least two pairs of power collector parts 90 in order to connect to two conductive rail segments at the same time. Preferably, as disclosed in connection to Figure 1 , the power collector comprises at least three power collector parts 90 in order to enable continuous uptake of power from an electric road track. A mutual distance of 50-80 cm for the power collector parts 90 in view of the travelling direction is suitable in order to collect power from an electric road system which is configured as exemplified in connection to Figure 1 .

The power collector comprises suitable electronic arrangements for enabling the power uptake through the power collector parts 90. The skilled person can by use of knowledge in the art achieve such a power collector.

An example of how the power supply of the conductive rail segments can be controlled will now be disclosed with reference to Figures 1 -3. It is appreciated that the power supply control can be achieved in various ways within the scope of the appended claims.

The power supply to the conductive rail segments 30a, which is to be positively charged, is provided by use of power supply controllers (not illustrated). A power supply controller is arranged in the inner space of each conductive rail segment 30a. The power supply controller may for example comprise a switch and other electronic arrangements which are available to the skilled person. The power supply controller is arranged to activate and deactivate the power supply to the conductive rail segment 30a in which it is arranged.

In order to activate the power supply when a power collector passes over the conductive rail segment 30a, the power supply controller is coupled to a vehicle sensor (not illustrated). The vehicle sensor is arranged in the inner space of the electrically isolating member 17 which is arranged just before the conductive rail segment 30a which is to be powered. The vehicle sensor comprises a coil connected in series with a capacitor. The vehicle sensor is arranged to receive a radio signal of a high frequency, such as 30 kHz, which is transmitted from a transmitter located in the front end of an approaching vehicle. The signal is received by means of the coil in the vehicle sensor. The vehicle sensor notifies thereupon the power supply controller by means of a suitable signal. The power supply controller activates the power supply to the conductive rail segment 30a. The power supply controller is arranged to deactivate the power supply after a predetermined time when it is assumed that the power collector of the vehicle has passed the conductive rail segment 30a. A suitable predetermined time may be in the range of ms, such as 50 ms.

By that the power supply is activated and deactivated in order to apply voltage to the conductive rail segment 30a only when a vehicle is passing over it, safety for surrounding objects and people is increased.

It is understood that the above disclosed embodiments may be combined or altered within the scope of the claims.