GB2519102A

GB2519102A - A cleaning device and a method of cleaning a system for inductive power transfer

Info

Publication number: GB2519102A
Application number: GB1317852.0A
Authority: GB
Inventors: Marnix Lannoije; Robert Czainski; Christian Wirth
Original assignee: Bombardier Transportation GmbH
Current assignee: Alstom Transportation Germany GmbH
Priority date: 2013-10-09
Filing date: 2013-10-09
Publication date: 2015-04-15
Also published as: GB201317852D0

Abstract

A cleaning device 1 and a method for an inductive power transmitter for a vehicle with a primary coil unit 10, has a belt 2 and means 3, 4 for driving the belt 2. At least part of the conveyor belt 2 is movable through a volume 15 above the transmission unit 10. The belt 2 may move in a direction parallel with or orthogonal to the longitudinal dimension of the transmitter 10. At least a partial section of the belt 2 above the transmitter 10 may be an electrical insulator. The whole of the conveyor belt 2 may be disposed above the coil 10. Removing means 8 which may be rubber lips may be disposed to remove foreign objects 16 from the belt when the belt 2 moves relative to the removing means 8. The belt 2 may only be actuated in the event that a foreign particle 16 is detected on the belt 2, and may only stop in the event that a foreign particle 16 is no longer detected.

Description

A cleaning device and a method of cleaning a system for inductive power transfer The invention relates to a cleaning device and a method of cleaning a system for inductive power transfer, in particular an inductive power transfer system for transferring electric energy to a vehicle which is standing or travelling on a surface of a route. Furthermore, the invention relates to a method of manufacturing such a cleaning device.

Vehicles, in particular electric vehicles, may comprise a so-called traction battery. The traction battery provides electric energy to power or to propel the vehicle. The electric energy stored in the traction battery can be dissipated by an electric machine which propels the electric vehicle. It is therefore necessary to charge the traction battery in order to provide sufficient electric energy to propel the electric vehicle.

Such vehicles may be provided with energy in different manners. One option is to charge an energy storage on-board the vehicle while the vehicle stops and by using an electric cable connection.

According to another option, the energy is transferred to the vehicle in a wireless manner using a magnetic field which induces an electric voltage in at least one inductance on-board the vehicle. The expression "receiving device" or "pick-up" has been used for the device which comprises at least one inductance. This approach can be used to charge the traction battery using an external source of electric energy, e.g. an external electrical network. For example, the aforementioned wireless manner uses an electromagnetic field to transfer electric energy to the vehicle, wherein an alternating voltage is induced on-board the vehicle. This alternating voltage has to be transformed such that a traction battery can be charged. In this case, an inductive power transfer system is used to transfer energy from a route side to the vehicle.

The inductive power transfer system usually comprises a route-sided primary unit with a primary winding structure. The primary winding structure generates a primary electromagnetic field which is received by a vehicle-sided secondary unit comprising a receiving device. In between the primary winding structure and a secondary winding structure of the receiving device, there is an air gap through which the primary field extends.

The inductive power transfer system can be a transfer system for so-called static energy transfer or static charging, wherein the vehicle to which the energy is transferred to does not move, i.e. is at a halt or rests. In this case, the primary unit can be designed as a so-called charging pad, wherein the charging pad is integrated into the route or mounted on the route surface (elevated charging pad).

A problem in such inductive power transfer systems is that it is generally not possible to mechanically prevent foreign objects, in particular objects made of electrically conductive material, e.g. made of metal, from being placed into proximity of the primary unit of an inductive power transfer system. Such foreign objects may e.g. be a coin, a can, a key, a tool or another object. The varying magnetic field generated by the primary unit and the secondary unit may induce current in the foreign objects made of the electrically conductive material and in other objects or fluids. Such currents may cause power losses and also heating of the object. Heating of the foreign objects may be dangerous for e.g. persons trying to touch and remove the foreign object and/or may damage the surface the foreign object is placed on or parts of the primary unit. Also, a heated object can cause fire.

US 2012/0200151 Al discloses a non-contact power supply control device controls power supply to transmit power in a non-contact manner from a ground-side power supply section provided outside a vehicle traveling using stored power to a vehicle-side power receiving section provided to the vehicle. A removal unit includes a blowing unit that blows air toward the ground-side pad.

It is a basic idea of the invention to provide a belt member which is arranged above a primary winding structure of a primary unit of a system for inductive power transfer, wherein the belt member is moveable through a volume located above the primary unit such that objects placed on the belt member are moved out of a volume through which the power transfer field generated by the primary winding structure extends.

A cleaning device for a system for inductive power transfer, in particular for inductive power transfer to a vehicle, is proposed.

The present invention can be applied in particular to the field of inductive energy transfer to any land vehicle, in particular track bound vehicles, such as rail vehicles (e.g. trams), but also to road automobiles, such as individual (private) passenger cars or public transport vehicles (e.g. busses). A problem in such devices is that it is generally not possible to mechanically prevent foreign objects, in particular objects made of an electrically conductive material, from being placed into proximity of the primary unit of an inductive power transfer system. Such foreign objects may e.g. comprise a coin, a can, a key, and a tool and other objects. The varying magnetic field generated by the primary unit and a secondary unit may induce current in the foreign objects made of the electrically conductive material and in other objects or fluids. Such currents may cause power losses and heating of the object. Heating of the foreign objects may be dangerous for e.g. persons trying to touch and remove the foreign object and/or may damage the surface the foreign object is placed on or pads of the primary unit. Also, a heated object can cause fire.

The system for inductive power transfer comprises at least a primary unit. The primary unit comprises at least one primary winding structure, wherein by means of the primary winding structure an alternating electromagnetic field can be generated. This alternating electromagnetic field can also be referred to as power transfer field or provide a portion of said power transfer field. Said power transfer field can be received e.g. by a secondary unit, in particular by a receiving device of a secondary unit, wherein the secondary unit comprises at least one secondary winding structure for receiving the power transfer field and for generating an alternating current output voltage. The secondary unit can be attached to a vehicle.

The secondary winding structure can generate a secondary field, e.g. if a current flows in the secondary winding structure. The current can e.g. be generated at least partially by the mutual induction between the primary winding structure and the secondary winding structure. It is also possible that the superposition of both fields, the primary and the secondary field, can be referred to as total power transfer field.

The cleaning device comprises at least a belt member and at least one actuating means for driving the belt member. The belt member can be designed as a conveyor belt or a conveyor band, preferably as an endless belt or endless band. The belt member can be driven by the actuating means, which can e.g. be designed as an electric machine, in particular a servomotor. It is, of course, possible, that the cleaning system comprises mechanical coupling means for coupling the actuating means and the belt member, e.g. a gear-wheel for transferring a rotary motion of a driven shaft of the actuating means into a movement of the belt member.

At least one section of the belt member is moveable through a volume located above or over the primary unit, in particular above or over the primary winding structure or a charging area (which will be explained later).

In the context of this invention, the term "above" relates to a coordinate system with a vertical axis extending into the main or principal direction of propagation of the power transfer field. The vertical direction can be oriented from the primary unit to a secondary unit if said secondary unit is arranged above the primary unit. The vertical direction can e.g. be oriented perpendicular to a plane, wherein the plane comprises the primary winding structure or an upper surface of the primary unit. Correspondingly, a longitudinal direction of the coordinate system can be oriented along a longitudinal axis of the primary unit. The longitudinal axis of the primary unit can correspond to or can be parallel to a longitudinal axis of the primary winding structure. A lateral direction can be oriented perpendicular to the previously explained vertical and longitudinal direction.

A base area of the volume located above the primary unit can have a predetermined size.

It is possible that a predetermined percentage of the power transfer field, e.g. a percentage larger than 70 %, 80 % or preferably 90 %, can extend through the base area of the volume located above the primary unit. It is also possible that the volume can enclose or comprise at least a part of the power transfer field if the primary winding structure is activated.

The belt member can extend parallel to an upper surface of the primary unit. This means that a surface plane of at least one section of the belt member is arranged parallel to the surface plane of the primary unit and arranged with a predetermined distance along the aforementioned vertical axis from the upper surface of the primary unit. If a vehicle is arranged above the primary unit such that inductive charging can be performed, the belt member can be arranged in an inner volume between the primary and the secondary unit.

The section of the belt member or the belt member in total can have predetermined dimensions, in particular predetermined dimensions in the aforementioned longitudinal and lateral direction. Preferably, the belt member has a width in the longitudinal direction which is equal to or higher than a width of the primary winding structure. The width of the primary winding structure can be a maximal width of an envelope of the primary winding structure along the longitudinal direction.

Also, the at least one section of the belt member can have a length in the aforementioned lateral direction which is equal to or higher than a length of the primary winding structure along the lateral direction. The length along the lateral direction of the primary winding structure can be a maximal length of an envelope of the primary winding structure along the lateral direction.

This, in turn, means that the at least one section of the belt member covers the primary winding structure or the primary unit fully or at least partially if both, the at least one section of the belt member and the primary winding structure or the primary unit are projected into a common plane of projection which is oriented perpendicular to the aforementioned vertical axis.

The belt member can comprise multiple sections, wherein in each driving state of the actuating means, a different section is located above the primary unit. For instance, an endless belt member can move continuously through the volume located above the primary unit.

In regions beside the primary unit, the belt member can comprise at least one section which extends in a direction comprising a vertical portion. In this case, objects placed on the belt member can fall of the belt member in region beside the primary unit. Region beside the primary unit denote regions which are not enclosed by an envelope of the primary winding structure or the primary unit in a common plane of projection of the primary winding structure or primary unit and the belt member.

The proposed cleaning device advantageously allows moving foreign objects located within the volume located above the primary unit out of said volume such that the foreign objects are not exposed to the power transfer field. The belt member in this context provides a simple means for removing the foreign objects.

In another embodiment, at least a predetermined part of the primary unit or the whole primary unit is covered by the at least one section of the belt member. "Covered" means that projections of the primary unit or primary winding structure and the at least one section of the belt member into a common plane of projection overlap at least partially, preferably fully.

Alternatively, a charging surface can be assigned to the primary unit, wherein the belt member is arranged such that a predetermined subarea of the charging area or the complete charging area is covered by the belt member. The charging surface can be a subpart of the surface of the route or the primary unit through which the power transfer field or a predetermined portion, e.g. a portion larger than 80%, 90% or 95%, of the power transfer field extends during inductive power transfer, in particular during static charging.

Alternatively, the charging area can be a subpart of the surface of the route or the primary unit which is enclosed by an envelope of the primary winding structure if the envelope is projected onto the surface of the route or the primary unit.

In each state of motion or in each driving state of the actuating means and the belt member, the proposed coverage is provided. The state of motion or driving state can be determined depending on a status of the actuation means, e.g. a rotary angle of driving shaft of the electric machine. Depending on the driving state, a particular section of the belt member is arranged in the aforementioned volume. Thus, in different driving states, the said coverage is provided by different sections of the belt member.

In a preferred embodiment, a direction of motion of the at least one section of the belt member which is moveable through the volume located above the primary unit comprises at least a portion which is oriented orthogonal to a longitudinal direction of the primary unit. This means, that the direction of motion comprises at least a portion which is oriented into the lateral direction. Preferably, the belt member is moveable through the volume above the primary unit in the lateral direction. This means that foreign objects are transported to a region beside the primary unit or the charging area in a lateral direction which provides a safer removal since such foreign objects are not in the way of a vehicle moving towards or away from the primary unit in a direction parallel to the longitudinal direction.

Alternatively, the direction of motion of the at least one section of the belt member which is moveable through the volume located above the primary unit is oriented into the longitudinal direction. If a vehicle, in particular a short vehicle, is positioned above the primary unit and the belt member, such an orientation advantageously allows to transport foreign objects to the front of the vehicle, in particular to a volume ahead of the vehicle, where they can be easily picked-up by the driver or another person.

In another embodiment, the at least one actuator is arranged beside the primary unit or the charging area. Preferably, the at least one actuating means is arranged beside the primary unit or the charging area in a lateral direction.

This advantageously minimizes the interference of the power transfer field and the actuation means of the belt member.

In another embodiment, the cleaning device comprises at least one guiding means for guiding the motion of the belt member. The guiding means can e.g. be designed as a guiding roll. A guiding roll can simultaneously provide a driving roll for driving the belt member.

The at least one guiding means can be arranged beside the primary unit, in particular beside the primary unit in a lateral direction.

This advantageously allows providing a desired driving path of the belt member e.g. a driving path for driving the at least one section of the belt member in a horizontal, particular lateral, direction of motion through the volume located above the primary unit and subsequently in a direction of motion which comprises at least a vertical portion in a volume beside the volume above the primary unit.

In a preferred embodiment, the cleaning device comprises at least one section which is free of electrically conductive material, wherein the section is arranged above the primary unit or the charging area. Said section is provided in each driving state. This means that in different driving states the section free of electrically conductive material can be provided by different sections of the belt member. A section free of electrically conductive material denotes a section of the cleaning device, wherein no electrically conductive elements, in particular metal objects or metal elements, of the cleaning device are located within said section.

This advantageously reduces an interference between the power transfer field and the cleaning device. In particular, the cleaning device will not heat up if it is exposed to a power transfer field. The belt member can e.g. be made of an electrically non-conductive material, e.g. plastic.

In another embodiment, the belt member provides a first plane section, a second plane section, a first connecting section and a second connecting section. The first connecting section provides a connection of the first and the second plane section at first ends of the first and second plane sections. The second connecting section provides a connection of the first and the second plane section at second ends of the first and the second plane sections. This means, that the belt member is designed as an endless belt member. In this context, plane means that a surface of the belt member, e.g. an upper surface with respect to the aforementioned vertical direction, is plane and oriented perpendicular to said vertical direction. The term plane also means that the surface of the belt member is a flat surface.

At least a subsection of the first and second plane section is arranged above the primary unit or above the charging area.

The proposed configuration is provided in each driving state of the belt member. In different driving states the said sections are provided by different sections of the belt member. If the belt member is driven by the actuating means, a particular section of the belt member will provide at least a subsection of all aforementioned sections during its movement.

The first and the second connecting section can be arranged beside the primary unit or the charging area, in particular beside the primary unit or the charging area in a lateral direction. The first and second plane section can be at least partially arranged within the volume located above the primary unit or the charging area. This configuration advantageously allows installing the proposed cleaning device within an existing system for inductive power transfer in a simple way. In particular, no removal of parts of the primary unit is necessary in order to arrange the proposed cleaning device. The second plane section can be arranged under the first plane section with respect to the aforementioned vertical direction.

It is of course possible that the second plane section extends under the primary unit or the primary winding structure with respect to the vertical direction. In this case, the primary unit can be enclosed by an endless belt member.

In another embodiment, a distance between the first and the second plane section in a vertical direction is smaller than the maximal vertical distance between belt member subsections within the first and the second connecting section.

This advantageously provides a very flat design of a cleaning device, especially a flat design of the parts which are arranged above primary unit. Thus, the small available space in between a primary and a secondary unit can be optimally used by the cleaning device.

In another embodiment, the cleaning device comprises at least one removing means. The removing means is designed and/or arranged such that a foreign object located on the belt member is removed from the belt member if the belt member and the removing means are moved relatively to each other, in particular if a predetermined relative movement is performed. Relative movement of the belt member and the removing means includes the cases wherein the removing means is moveable and the belt member is stationary during the removal of foreign objects or wherein the belt member is moveable and the removing means is stationary during removal or wherein the belt member and the removing means are moveable during removal.

It is for instance possible that the removing means is designed and/or arranged relative to at least one section, in particular to one of the previously explained connecting section of the belt member, such that a mechanical contact between an object located on the belt member and a removing means is provided during relative movement. The mechanical contact can be provided such that a removal force is exhibited on the foreign object such that it is removed from the belt member.

The removing means can be in contact with a surface of the belt member or can be located with a predetermined (small) distance away from the belt member.

This advantageously provides a cleaning means for the belt member so that foreign object transported away from the volume located above the primary unit can be removed from the belt member. So, in particular if the belt member is an endless belt member, the section of the belt member which carried the foreign object can be again moved into the volume located above the primary unit.

In a preferred embodiment, the removing means is designed as a rubber lip, wherein a free end of the rubber lip touches the belt member, preferably one particular section, more particular the aforementioned connecting section, provided by the belt member.

Alternatively, the free end of the rubber lip is arranged with a predetermined distance away from the belt member. The distance can be measured in a direction perpendicular to a surface of the belt member. The design as a rubber lip advantageously provides a reliable removal of foreign objects from the belt member while being flexible to different shapes of foreign objects to be removed.

In another preferred embodiment, the removing means is arranged such that only foreign objects in a connecting section are removed. This means that foreign objects on the belt member can enter a connecting section and are removed from the connecting section by the removing means. As the connecting section can be arranged beside the primary unit or the charging area, foreign objects are also removed from the belt member beside the primary unit. This advantageously minimizes the possibility that objects removed from the belt member fall back into the volume located above the primary unit or the charging area.

In another embodiment, a maximal vertical distance between the belt member and the upper surface of the primary unit, or the surface of the route, is chosen such that a minimal possible vertical distance between the belt member and a surface of a secondary unit is larger than zero. This means that belt member can be arranged between the primary unit and the secondary unit without contacting, e.g. touching, the secondary unit.

In another embodiment, the cleaning device comprises at least one object detection means, wherein the belt member is only actuatable if at least one foreign object is detected in a predetermined surveillance volume by the object detection means. The surveillance volume can correspond to the volume located above the primary unit or enclose said volume at least partially. If a foreign object is detected, an inductive power transfer can be disabled.

The object detection means can e.g. be provided by an image capturing device and a corresponding evaluation unit.

Alternatively or in addition, the detection system can e.g. comprise at least one inductive sensing system, wherein the inductive sensing system comprises one or multiple detection winding(s). Multiple detection windings can be arranged in an array structure, wherein the array structure covers the aforementioned charging surface of the route at least partially.

Using an inductive detection system, an active or passive detection can be realized. In the case of an active detection, one or more excitation winding(s) is/are used. An active object detection is performed by monitoring changes of properties of an excitation field generated by the excitation winding(s). In the case of a passive detection, only one or more passive winding(s) is/are used. The passive object detection is performed by monitoring changes of properties of the passive winding(s), in particular an inductance of the winding(s).

Such an inductive detection system is disclosed in GB 1222712.0 (not yet published). In the context of this invention, a detection system can be designed according to one of the embodiments claimed in GB 1222712.0.

In the case of a capacitive detection, the detection system can comprise at least one capacitive sensing system, wherein the capacitive sensing system comprises one or multiple detection capacitors. Multiple detection capacitors can be are arranged in an array structure, wherein the array structure covers the charging surface at least partially.

Using a passive detection system, a passive object detection is performed by monitoring changes of properties of the detection capacitor(s), in particular a capacitance of the detection capacitor(s).

Such a capacitive detection system is disclosed in the GB 1222713.8 (not yet published).

In the context of this invention, a detection system can be designed according to one of the embodiments claimed in GB 1222713.8.

Alternatively or in addition, the detection system can e.g. comprise one force sensor for sensing a force exerted by a foreign object on at least one of the elements of the proposed cleaning device, wherein a force-based detection can be performed by the detection system. This will be explained later.

This advantageously provides an energy saving cleaning device as the belt member is only actuated if a foreign object to be removed is detected.

Alternatively, the belt member can be actuated independent of a detected foreign object.

The belt member can be actuated if a predetermined activation signal is detected. More particular, the belt member can be actuated such that a desired movement of the belt member is performed, e.g. a full turn or full cycle of the belt member.

It is, for instance possible, that the belt member is actuated if an activation signal for inductive power transfer is detected. In this case, inductive power transfer can be started or enabled only after the movement of the belt member has been terminated. It is also possible that the belt member is actuated if an activation signal for the proposed cleaning device is detected, e.g. within a start-up sequence.

In another embodiment, the cleaning device comprises at least one object detection means, wherein an actuation of the belt member is only terminated if no foreign object is detected in a predetermined surveillance volume by the object detection means. An (disabled) inductive power transfer can be enabled if no foreign object is detected or the actuation of the belt member is terminated.

This advantageously provides a reliable removable of foreign objects since the cleaning device is only deactivated if all foreign objects to be removed are removed.

Further proposed is a method of cleaning a system for inductive power transfer, in particular for inductive power transfer to a vehicle. At least one section of a belt member is arranged above a primary unit, in particular above a primary winding structure or a charging area, of the system for inductive power transfer. The method comprises the step of actuating the belt member such that the at least one section of the belt member is moved through a volume located above the primary unit.

The term actuating comprises the case that the belt member is driven by the actuating means. Preferably, the belt member is actuated such that the at least one section of the belt member is moved through the volume and out of the volume located above the primary unit. Further, foreign objects located on the at least one section of the belt member can be removed from the belt member, e.g. by a removal means. It is possibly, that the removal of foreign objects from the belt member is exclusively performed outside the area located above the primary unit.

This advantageously provides a reliable and fast method for removing foreign objects from primary unit.

In another embodiment, the belt member is only actuated if a foreign object in a predetermined surveillance volume is detected. As explained previously, this provides an energy saving method for moving foreign objects from a primary unit. Alternatively, the belt member can be actuated independent of a detected foreign object.

In another embodiment, an actuation of the belt member is terminated only if no foreign object is detected in a predetermined surveillance volume. This advantageously allows a reliable removal of foreign objects from the primary unit.

Further proposed is a method of manufacturing an inductive power transfer system, wherein the inductive power transfer system comprises at least one primary unit. The method comprises the steps of -providing a cleaning device according to one of the previously explained embodiments, -arranging the cleaning device such that at least one section of a belt member of the cleaning device is moveable through a volume located above the primary unit, in particular above a primary winding structure or a charging area.

Examples of the invention will be described with references to the attached figures. The figures show: Fig. 1 a schematic side view of a cleaning device according to the invention, Fig. 2 a schematic side view of a belt member and corresponding guiding means, Fig. 3 a schematic side view of a cleaning device and a system for inductive power transfer, Fig. 4 a top view on a cleaning device and a system for inductive power transfer according to Fig. 3, Fig. 5 a schematic side view of a second embodiment of the cleaning device according to the invention and Fig. 6 a schematic side view of a third embodiment of the cleaning device according to the invention.

Fig. 1 shows a cleaning device 1 for a system for inductive power transfer to a vehicle.

The cleaning device 1 comprises an endless belt member 2. The belt member 2 is spanned in between a first guiding roll 3 and a second guiding roll 4, wherein the belt member 2 encompasses the guiding rolls 3, 4. The guiding roll 3 is designed as a driving roll, wherein sections of the belt member are moved along the closed path provided by the endless belt member 2 if the driving roll is actuated. The driving roll can e.g. be actuated or driven by an actuator 19 (see Fig. 5). Thus, rotary motion of the driving roll 3 converts into a movement of the belt member 2.

Further shown are a third guiding roll 5 and a fourth guiding roll 6 for guiding a course of the endless belt member 2. Thus, a desired course and movement path of the belt member 2 can be provided.

Also shown is a coordinate system with a vertical direction z which is oriented perpendicular to an upper surface 7 of the belt member 2, in particular perpendicular to a first plane section al (see Fig. 2) of the belt member 2. Further shown is a lateral direction y which is oriented perpendicular to the vertical direction z. The lateral direction y is oriented parallel to the aforementioned upper surface of the belt member 2, in particular of the surface of the belt member 2 within the first plane section al. Also, the lateral direction y points from a central rotary axis of the second guiding roll 4 towards a central rotary axis of the first guiding roll 3. Not shown in Fig. 1 is a longitudinal direction x (see Fig. 4) which extends perpendicular to the aforementioned vertical direction z and lateral direction y.

Further shown is a rubber lip 8 which is arranged such that a pointed end of the rubber lip 8 touches the belt member 2 within a section of the belt member 2 which encompasses the driving roll or first guiding roll 3.

A preferred direction of motion of the belt member 2 is shown by arrows 9.

Fig. 2 shows another schematic side view of the cleaning device 1, wherein different sections al, a2, bi, b2 provided by the belt member 2 are shown. In particular, the belt member 2 provides a first plane section al, a second plane section a2, a first connecting section bi and a second connecting section b2. If the belt member 2 is moved along its movement path, different sections of belt member 2 will provide the first plane section al, the second plane section a2, the first connecting section bi and the second connecting section b2. It is shown that within the first plane section al and the second plane section a2, a surface of the belt member 2 (or at least of the sections of the belt member 2 which provide the first and the second plane section al, a2) is oriented perpendicular to the vertical direction z. The movement of the belt member 2 within the plane sections al, a2 is oriented exclusively along or against the lateral direction y.

Within the connecting sections bi, b2, the course of the belt member 2 extends also partially into and against the vertical direction z. This means that foreign objects 16 (see e.g. Fig. 3) which are placed on the belt member 2 within the first plane section al and subsequently transported to the first connecting section bi can fall of the belt member 2 within the first connecting section bi. In case that the foreign object 16 sticks to the belt member 2, e.g. if belt member 2 is wet or the foreign object is adhesive, the rubber lip 8 will support removal of such a foreign object 16 from the belt member 2 within the first connecting section bi. It is shown that the rubber lip 8 is arranged within the first connecting section bi.

Also shown is that a distance Dl of the first and the second plane section al, a2 in the vertical direction z is smaller than the maximal vertical distance D2 of the belt member subsections within the first and the second connecting section bl, b2 in the vertical direction z. Thus, the belt member 2 provides at least partially a low profile, in particular by the first and the second plane section al, a2.

Fig. 3 shows a cleaning device and a system for inductive power transfer. The system for inductive power transfer comprises a route-sided primary unit 10 which comprises a primary winding structure 11. Further, the system of inductive power transfer comprises a vehicle-sided secondary unit 12 which can be also referred to as receiving device. The receiving device comprises a secondary winding structure 13. A main propagation direction of an electromagnetic power transfer field which is generated by the primary winding structure 11 is visualized by an arrow 14 and extends along the vertical direction z. Also shown is a volume 15 located above the primary unit 10. The volume 15 is shown by dotted lines. The volume 15 corresponds to or comprises a volume located above the primary winding structure 11, in particular located above an envelope of the primary winding structure 11 with minimal dimensions. A base area of the volume 15 can correspond to said envelope of the primary winding structure 11. The base area can also be denoted as a charging area 18 (see Fig. 4) of the primary unit 10, wherein edges of the charging area 18 correspond to edges of the volume 15. Thus, in a common plane of projection of the volume 15 and the envelope of the primary winding structure 11, edges of the volume 15 correspond to edges of the envelope.

The cleaning device 1 is arranged such that the belt member 2, in particular the first and the second plane section al, a2 provided by the belt member 2 are located above the primary unit 10 with respect to the vertical direction z, in particular located above the primary winding structure 11. Thus, at least one section of the belt member 2 is moveable through the volume 15 located above the primary unit 15, in particular the volume 15 located above the primary winding structure 11 or the charging area 18. A foreign object 16 which is located on the belt member 2 within the volume 15 can thus be removed from the volume 15. As a result, the foreign object 16 is not exposed to the power transfer field generated by the primary winding structure 11. Further shown is another foreign object 17 which is removed from the belt member 2 within the first connecting section bl, in particular by the rubber lip 8.

Further shown is that if the belt member 2 is made of an electrically non-conductive material, the first and the second plane sections al, a2 of the belt member 2 provide a section free of electrically conductive material. Since these sections al, a2 are exposed to the power transfer field, no interference of said power transfer field with the cleaning device 1 will occur.

Fig. 4 shows a top view on the cleaning device 1 and the system for inductive power transfer shown in Fig. 3.

It is shown that a maximal width Wi of the belt member 2 in the lateral direction y is larger than a maximal width W2 of the volume 15 and also larger than a width of the primary unit 10. Further, a maximal length Li of the belt member 2 along the longitudinal direction xis larger than a maximal length L2 of the volume 15 along the longitudinal direction x and also longer than a maximal length of the primary unit 10. Thus, in a common plane of projection which is orthogonal to the vertical direction z (see e.g. Fig. 3), the belt member 2, in particular the first plane section ai (see e.g. Fig. 3) covers the primary unit 10 or at least the primary winding structure 11 (see Fig. 3) of the primary unit 10.

Fig. 5 shows a schematic side view of a second embodiment of the cleaning device 1 according to the invention. The cleaning device i shown in Fig. 5 is designed similar to the cleaning device i shown in Fig. 1. In contrast to Fig. i, an actuator 19 is shown which is coupled to the driving roll 3. The actuator 19 and/or the coupling of the actuator 19 to the driving roll 3 is designed such that the driving roll 3 can be rotated by the actuator 19.

The actuator i 9 can e.g. be designed as an electric machine, e.g. a servomotor, wherein an output axis of the electric machine is coupled to a central axis of the driving roll 3.

Further shown is an energy supply unit 20, e.g. a battery or a power network connection, which provides the energy for an operation of the actuator 19. Further shown is a power sensor 21 which senses an input power of the actuator 19. This can e.g. be done by sensing an input current and/or input voltage of the actuator 19. If the input power is higher than a predetermined threshold value, a fault condition can be detected. Such a fault condition can e.g. be provided by a blocked belt member 2. If a fault condition is detected, the actuator 19 can be switched off. Also, a current or a future inductive power transfer can be disabled if a fault condition is detected. In this case, the inductive power transfer can only be enabled if the fault condition is reversed.

Fig. 6 shows a schematic side view of a third embodiment of the cleaning device according to the invention. Again, the cleaning device 1 shown in Fig. 6 is designed similar to the cleaning device 1 shown in Fig. 1. In contrast to Fig. 1, the cleaning device 1 comprises at least one sensor to sense an object-based force component which acts on the belt member 2 or is transferred via the belt member 2 to the guiding rolls 3, 4, 5, 6.

The object-based force component denotes a force component which is based on the weight of a foreign object 16 located on the belt member 2. If a foreign object 16, in particular a heavy foreign object 16 like a cobblestone, is located on an upper surface 7 of the belt member 2, a force generated by the weight of the foreign object 16 will be exerted on the belt member 2. Via the belt member 2, said force will be transferred to the guiding rolls 3, 4, 5, 6. Shown are force sensors 22a, 22b, 22c, 22d, wherein each force sensor 22a, 22b, 22c, 22d senses a force exerted on one of the guiding rolls 3, 4, 5, 6. For example, the force sensors 22a, 22b, 22c, 22d can be arranged such that a force exerted from the guiding rolls 3, 4, 5, 6 on a bearing element (not shown) of the respective guiding roll 3, 4, 5, 6 or a central axis or a rotary axis of the respective guiding roll 3, 4, 5, 6 is sensed. It is understood that the sensed force can be corrected from force components which are not generated by the weight of the foreign object 16 such as a force generated by the weight of the respective guiding roll 3, 4, 5, 6. If the detected and, if applicable, corrected force component fulfils at least one predetermined force-based criteria, the presence of a foreign object 16 can be detected. A force-based criterion can e.g. be fulfilled if the direction of the detected force is within a predetermined range of directions and/or if the force magnitude is higher than a predetermined threshold value.

The threshold value can be chosen depending on the minimal weight of a foreign object which is to be detected.

Thus, an object detection system or means can comprises at least one force sensors 22a, 22b, 22c, 22d and at least one evaluation unit, wherein the force sensor 22a, 22b, 22c, 22d can be arranged and/or designed such that a force exerted by a foreign object 16 on at least one element of the proposed cleaning device can be detected. This allows a force-based detection of a foreign object 16.

It is, of course, possible to derive the force value from an output signal of another sensor type, e.g. a pressure sensor. Thus, in addition or instead of the shown force sensors 22a, 22b, 22c, 22d, pressure sensors can be used.

Also, the strain or the expansion of the belt member 2 can be sensed, e.g. by at least one strain gauge. If a foreign object 16, in particular a heavy foreign object 16 like a cobblestone, is located on the upper surface 7 of the belt member 2, the strain or tension of the belt member 2 will increase. Also, depending on the material of the belt member, the length of the belt member 2 can increase. Thus, it is possible to detect the presence of a foreign object by evaluating an output signal of at least one sensing means for sensing the strain or the expansion of the belt member 2.

Thus, an object detection system or means can comprises at least one means for sensing the strain or the expansion of the belt member and at least one evaluation unit, wherein the sensing means can be arranged and/or designed such that a strain or expansion of the belt member 2 generated by the weight of a foreign object 16 can be detected. This allows a strain-or expansion-based detection of a foreign object 16.

This advantageously allows a detection or even discrimination of heavy foreign objects such as a cobblestone.

Claims

Claims 1. A cleaning device for a system for inductive power transfer, in particular for inductive power transfer to a vehicle, wherein the system for inductive power transfer comprises at least a primary unit (10), characterized in that the cleaning device (1) comprises at least a belt member (2) and at least one actuating means for driving the belt member (2), wherein at least one section of the belt member (2) is movable through a volume (15) located above the primary unit (10).
2. The cleaning device according to claim 1, wherein at least a predetermined part of the primary unit (10) or the whole primary unit (10) is covered by the at least one section of the belt member (2) or wherein a charging area (18) is assigned to the primary unit (10), wherein the belt member (2) is arranged such that a predetermined subarea of the charging area (18) or the complete charging area (18) is covered by the belt member (2).
3. The cleaning device according to claim 1 or 2, wherein a direction of motion of the at least one section of the belt member (2) which is movable through the volume (15) located above the primary unit (10) comprises at least a portion which is oriented orthogonal to a longitudinal direction (x) of the primary unit (10) or is oriented into the longitudinal direction (x).
4. The cleaning device according to one of the claims 1 to 3, wherein the at least one actuating means is arranged beside the primary unit (10) or the charging area (18).
5. The cleaning device according to one of the claims 1 to 4, wherein the cleaning device (1) comprises at least one guiding means for guiding the motion of the belt member (2).
6. The cleaning device according to one of the claims 1 to 5, wherein cleaning device (1) comprises at least one section which is free of electrically conductive material, wherein the section is arranged above the primary unit (10) or the charging area (18).
7. The cleaning device according to one of the claims 1 to 6, wherein the belt member (2) provides a first plane section (al), a second plane section (a2), a first connecting section (bi)and a second connecting section (b2), wherein the first connecting section (bi) provides a connection of the first and the second plane section (al, a2) at a first ends of the first and second plane sections (al, a2), wherein the second connecting section (b2) provides a connection of the first and the second plane section (al, a2) at second ends of the first and the second plane sections (al, a2), wherein at least a subsection of the first and the second plane section (al, a2) are arranged above the primary unit (10) or the charging area (1 8).
8. The cleaning device according to claim 7, wherein a distance (Dl) between the first and the second plane section (al, a2) in a vertical direction (z) is smaller than the maximal vertical distance (D2) between belt member subsections within the first and the second connecting section (bl, b2).
9. The cleaning device according to one of the claims 1 to 8, wherein the cleaning device (1) comprises at least one removing means, wherein the removing means is designed and/or arranged such that a foreign object (16) located on the belt member (2) is removed from the belt member (2) if the belt member (2) and the removing means move relatively to each other.
10. The cleaning device according to claim 9, wherein the removing means is designed as a rubber lip (8), wherein a free end of the rupper lip (8) touches the belt member (2) or is arranged with a predetermined distance away from the belt member (2).
11. The cleaning device according to one of the claims 8 or 9, wherein the removing means is arranged such that only foreign objects on a connecting section (bl, b2) are removed.
12. The cleaning device according to one of the claims 1 to 11, wherein a maximal vertical distance between the belt member (2) and the upper surface of the primary unit (10) is chosen such that a minimal possible vertical distance between the belt member (2) and a surface of a secondary unit is larger than zero.
13. The cleaning device according to one of the claims 1 to 12, wherein the cleaning device (1) comprises at least one object detection means, wherein the belt member (2) is only actuatable if at least one foreign object (16) is detected in a predetermined surveillance volume by the object detection means or wherein the belt member (2) is actuatable if a predetermined activation signal is detected.
14. The cleaning device according to one of the claims 1 to 13, wherein the cleaning device (1) comprises at least one object detection means, wherein an actuation of the belt member (2) is only terminated if no foreign object (16) is detected in a predetermined surveillance volume by the object detection means.
15. A method of cleaning a system for inductive power transfer, in particular for inductive power transfer to a vehicle, wherein at least one section of a belt member (2) is arranged above a primary unit (10) of the system for inductive power transfer, comprising the step of -actuating the belt member (2) such that the at least one section of the belt member (2) is moved through a volume (15) located above the primary unit (10).
16. The method according to claim 15, wherein the belt member (2) is only actuated if a foreign object (16) in a predetermined surveillance volume is detected or if a predetermined activation signal is detected.
17. The method according to one of the claims 15 to 16, wherein an actuation of the belt member (2) is terminated only if no foreign object (16) is detected in a predetermined surveillance volume.
18. A method of manufacturing an inductive power transfer system, wherein the inductive power transfer system comprises at least one primary unit (10), comprising the steps of -providing a cleaning device (1) according to one of the claims 1 to 14, -arranging the cleaning device (1) such that at least one section of a belt member (2) of the cleaning device (1) is movable through a volume (15) located above the primary unit (10).