Current collector for an electric or hybrid-electric vehicle, and vehicle equipped with such a current collector
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2026-03-11
Smart Images
Figure EP2024067911_13032025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Pantograph for an electric or hybrid-electric vehicle and a vehicle equipped with such a pantograph
[0003] The invention relates to a current collector for an electrically or hybrid-electrically driven vehicle according to the preamble of patent claim 1 and to a vehicle equipped with such a current collector according to patent claim 8.
[0004] Such pantographs are intended for feeding electrical traction energy from a two-pole electrical overhead line system into a road vehicle, in particular into a heavy commercial vehicle such as a lorry or bus, for supplying an electric or hybrid-electric traction drive of the road vehicle. For this purpose, the overhead line system comprises two contact wires carrying a traction voltage, for example in the form of a direct voltage. The contact wires are stretched along a carriageway used by the road vehicle above the lane in use. The pantograph comprises an adjustable support rod. The support rod can be rotatably supported on the road vehicle via a base joint on the vehicle side. On the contact wire side, the support rod carries two contact rockers, each rotatably connected to the support rod via a rocker joint.At least one contact strip extending in the transverse direction of the vehicle is spring-mounted on each rocker support. Each contact strip has a contact surface facing upwards in the vertical direction of the vehicle for contact with a contact wire. Such a pantograph is known, for example, from patent EP 3 571 086 B1.
[0005] Unlike rail vehicles, pantographs on road vehicles experience a much broader spectrum of vibrations in the contact bars relative to the contact wires. This is primarily because, unlike rail traffic, road vehicles are not lane-bound and roadways have a multitude of disturbances that cause vibrations, such as rough or changing road surfaces, potholes, bumps, ruts or even objects lying on the roadway, such as lost vehicle parts or cargo. Rolling over such a disturbance imprints vibrations from the vertically deflected vehicle wheel via the chassis into the pantograph, which can impair the quality of contact or even break the contact between the contact bars and the contact wires. This results in arcing, which causes increased electrical wear on the contact bars.At the same time, the arcs cause strong electromagnetic interference in the pantograph's sensors and electronics. Contact failures in road vehicles result in voltage surges and hybrid faults in the power electronics. Such consequences shorten the service life of a pantograph's contact strips, can lead to the pantograph lowering, or even require a restart of the vehicle's electronics. During these downtimes, the road vehicle cannot feed in traction energy from the overhead line system.
[0006] From the publication EP 3 929 024 A1 it is known to arrange a vibration absorber at the contact wire side end of the support frame, which is designed to dampen vertical vibrations of the support frame and the contact rockers introduced by the vehicle. However, this method has its limitations, since the last sprung mass, namely that of the contact strips, cannot be reduced arbitrarily and thus an inertia that cannot be fully compensated for remains in the vibration system. The very broadband excitation of the vibration system still contains spectral excitation bands which, together with disturbance excitations due to bumps, roughness and the like, lead to brief contact losses. The invention is therefore based on the object of providing a current collector of the type mentioned at the outset with higher availability.
[0007] The object is achieved according to the invention by a generic current collector with the features specified in the characterizing part of patent claim 1.
[0008] The invention is based on a current collector for an electrically or hybrid-electrically powered road vehicle, for example for a heavy commercial vehicle such as a truck or a bus. The current collector is suitable and intended for feeding in traction energy from two contact wires of a two-pole overhead line system. The contact wires can be stretched parallel to one another and above a lane of a carriageway of the road vehicle and carry a traction voltage, for example a direct voltage, for the electrical supply of a traction drive of the road vehicle while it is moving. The current collector comprises an erectable support rod which can be rotatably supported on the road vehicle via a base joint. The base joint can be mounted on a main frame of the current collector which is supported on a chassis of the road vehicle.On the contact wire side, the support rod carries two contact rockers, each rotatably connected to the support rod by a rocker joint. The support rod can be pantograph-like and have a lower arm and two upper arms connected to it by a knee joint, with each upper arm carrying a contact rocker. At least one contact strip extending in a transverse direction of the vehicle is spring-mounted on each of the contact rockers. Two contact strips can also be provided for each contact rocker, arranged one behind the other in a longitudinal direction of the vehicle. Each of the contact strips has a contact surface facing upwards in a vertical direction of the vehicle for a sliding contact with a contact wire of the overhead line system.A lifting device can be provided for raising and lowering the support rod, whereby the contact strips are movable between a lowered rest position in which the contact rockers are placed at the height of a vehicle roof, and a raised contact position in which an electrical contact - or an electrical sliding contact when the road vehicle is in motion - is established between the contact surfaces of the contact strips and the contact wires.
[0009] According to the invention, an electrically conductive, flexurally elastic sheet-like structure with a longitudinal extent and a transverse extent is arranged on at least one contact strip of each contact rocker in such a way that its longitudinal extent extends in the transverse direction of the vehicle along the contact strip and that its transverse extent projects upwards beyond the contact surface by a projection in the vertical direction of the vehicle. Starting from a contact wire regularly resting on the contact surface of a contact strip, the projection of the electrically conductive sheet-like structure maintains the conductive contact in the event of vibration-induced relative movements in the vertical direction between the contact strip and the contact wire, provided that these movements do not exceed the projection height.The gap created by oscillation between the contact surface of the contact strip and the underside of the contact wire is electrically bridged by the sheet material, so that undesirable arcs are hardly or not at all formed. The oscillation amplitude of the contact strip to the contact wire, up to which electrical contact is to be maintained during relative movements of these contact partners, is measured via the transverse extent of the sheet material or the size of its projection. The size of the optimal projection can therefore be determined through field tests, which are influenced by the vibration characteristics of the road vehicle and the pantograph, as well as the condition of the road surface.The longitudinal extent of the sheet material can correspond to the entire length of the contact strip, but it can also be restricted to a smaller working range of the contact strip, within which the contact point between the contact strip and the contact wire can oscillate during operation. In any case, the contact wire glides along the sheet material for each contact point. The sheet material is partially bent by the contact wire as it slides along, but due to its high bending elasticity, it returns to its upright, e.g. flat, shape when the position of the contact point changes at the point left by the contact wire. The bending of the sheet material by the contact wire preferably occurs locally at or around the contact point and, due to the low thickness of the sheet material, does not generate any appreciable friction losses.The sheet material can, for example, be designed as a thin, soft, and flexurally elastic film made of a material with high electrical conductivity, such as a metal alloy. A current flowing through the sheet material when a gap occurs between the contact strip assigned to this sheet material and a contact wire has a low current intensity, since it can be assumed that electrical contact between other contact strips and contact wires will continue. Furthermore, this condition typically only lasts for a short time.
[0010] In an advantageous embodiment of the current collector according to the invention, the sheet-like structure is comb-like and has a back web for fastening the sheet-like structure to the contact strip, as well as a row of parallel, flexurally elastic filaments projecting upwards from the back web. The filaments of the sheet-like structure, corresponding to the teeth of a comb, can be formed by highly elastic wires, for example made of a superelastic metal alloy such as nitinol or of spring steel. The filaments can also be formed by punching out filament spaces from a metal foil. A contact wire gliding through such a sheet-like structure only has to bend as many filaments as its diameter requires. The filaments are soft and elastic and have only a low spring return force.The filaments are connected to a back bar corresponding to the comb back, which serves to attach the fabric to the grinding strip, for example to a grinding piece holder carrying the grinding piece.
[0011] In a further advantageous embodiment of the current collector according to the invention, the filaments have a straight central section and a curved end section. The straight central section can extend parallel to a vehicle's vertical direction, followed by an end section that is slightly curved backwards, i.e., counter to the direction of travel of the road vehicle. The curvature of the curved end section allows a filament to evade the contact wire by bending it at the smallest possible deflection angle.
[0012] In a further advantageous embodiment of the current collector according to the invention, the filaments are designed as parallel, helically wound spring elements. Instead of, or in combination with, straight or slightly bent wire sections, filaments can also be wound in a helical configuration. Such a helical spring is flexible and elastic and can also be made of a metal alloy with high electrical conductivity.
[0013] In a further advantageous embodiment of the current collector according to the invention, the sheet-like structure is in a net-like manner and has filaments that are connected knotlessly or in knots. The filaments of the sheet-like structure can be interwoven, braided, interwoven, or knitted in a plain weave or in some other way. The filaments running towards the edge of the net-like structure can be fed back into the net to form a bend. The thickness of the filaments and the size of the mesh of the net are designed such that the sheet-like structure is soft and flexible so that it can be locally bent by a contact wire. The filaments connected in a net-like manner are made of an electrically conductive material so that they can conduct current if gaps form between the contact strip and the contact wire due to vibrations of the current collector.
[0014] In a further advantageous embodiment of the current collector according to the invention, a sheet-like structure is detachably connected to a contact piece holder carrying the contact piece. The sheet-like structure can be secured at its backing web, for example, by screw connections to the contact piece holder made of aluminum. The screw connection is electrically conductive and enables a worn sheet-like structure to be quickly replaced with a new one.
[0015] In a further advantageous embodiment of the current collector according to the invention, the contact strip holder has, with respect to a vehicle longitudinal direction, a front side facing the direction of travel of the road vehicle and a rear side facing away from the direction of travel, wherein the sheet-like structure is connected to the contact strip holder at the rear. Due to the rear fastening of a sheet-like structure to the contact strip holder, the filaments have free spring travel when bent by the contact wire away from the contact strip, whereby the soft and elastic material properties of the filaments can unfold undisturbed during bending.
[0016] The invention also relates to a road vehicle, in particular a heavy commercial vehicle, which comprises an electric or hybrid-electric traction drive and a current collector according to one of the preceding claims for feeding traction energy from two contact wires of a two-pole overhead line system.
[0017] Further features and advantages of the invention will become apparent from an embodiment described in more detail below with reference to the drawings, in which
[0018] FIG 1 shows a road vehicle according to the invention in side view, FIG 2 shows the road vehicle from FIG 1 in front view,
[0019] FIG 3 shows a contact strip of a pantograph according to the invention in a perspective view, contacting a contact wire,
[0020] FIG 4 shows a first embodiment of a surface structure in front view,
[0021] FIG 5 a second embodiment of a surface structure in front view,
[0022] FIG 6 a third embodiment of a surface structure in front view,
[0023] FIG 7 a cross section through a grinding strip with surface structure,
[0024] FIG 8 a cross section through the contact strip from FIG 7 in contact with a contact wire and
[0025] FIG 9 shows a cross section through the contact strip from FIG 7 which is deflected slightly downwards by the contact wire.
[0026] According to FIGS. 1 and 2, a road vehicle 1 according to the invention, which may be a heavy commercial vehicle, such as a semitrailer tractor, comprises an electric or hybrid-electric traction drive 2 and a current collector 3 for feeding traction energy from two contact wires 4 of a two-pole overhead line system, known per se and therefore not shown in detail. The contact wires 4 are arranged parallel to one another and stretched above a lane of a carriageway 5 of the road vehicle 1 and carry, for example, a direct voltage for the electrical traction supply of the road vehicle 1 while driving.
[0027] 1 and 2, the current collector 3 comprises an erectable support rod 6 with an end on the vehicle side and an opposite end on the contact wire side. The support rod 6 is rotatably supported on the road vehicle 1 via a base joint 7, the base joint 7 being mounted on a main frame 9 of the current collector 3 which is supported on a chassis 8 of the road vehicle 1. On the contact wire side, the support rod 6 carries two contact rockers 11, each rotatably connected to the support rod 6 via a rocker joint 10. In the exemplary embodiment shown, the support rod 6 is pantograph-like and has a lower arm 12 and two upper arms 14 connected to the lower arm 12 via a knee joint 13. Each of the upper arms 14 carries one of the two contact rockers 11. On each of the contact rockers 11, two sliding strips 15 extending in a transverse direction Y of the vehicle are resiliently mounted, for example via leaf springs 30.The two contact strips 15 of a contact rocker 11 are arranged one behind the other as seen in a vehicle longitudinal direction X. Each of the contact strips 15 has a contact surface 16 facing upwards in a vehicle vertical direction Z for a sliding contact with a contact wire 4 of the overhead line system. A lifting device 17, designed for example as an air bellows, is provided for raising and lowering the support rod 6. This allows the contact strips 15 to be moved between a lowered rest position and a raised contact position. In the rest position, the contact rockers 11 are stored at the level of a vehicle roof 18. In the contact position, an electrical contact - an electrical sliding contact when the road vehicle 1 is in motion - is established between the contact surfaces 16 of the contact strips 15 and the contact wires 4.
[0028] On at least one contact strip 15 of each contact rocker 11, preferably on the rear of the two contact strips 15 as seen in a direction of travel V, an electrically conductive, flexurally elastic sheet-like structure 19 with a longitudinal extent L and a transverse extent B is arranged according to FIGS. 1 to 3. Its contour is illustrated by a dash-dot line. The sheet-like structure 19 extends with its longitudinal extent L in the vehicle transverse direction Y along the respective contact strip 15. With its transverse extent B, the sheet-like structure 19 projects upwards over the contact surface 16 by a projection S in the vehicle vertical direction Z.Starting from a contact wire 4 regularly resting on the contact surface 16 of a contact strip 15, the projection S of the electrically conductive surface structure 19 maintains the conductive energy transfer during vibration-induced relative movements in the vertical direction Z of the vehicle between the contact strip 15 and the contact wire 4, provided that these contact partners do not move away from each other by more than the size of the projection S. Such a vertical vibration can occur, for example, when the road vehicle 1 drives through a pothole 31 in the surface of the roadway 5. The vertical gap between the contact strip 15 and the contact wire 4 caused by an vibrational movement is electrically bridged by the surface structure 19, so that there is hardly any formation of unwanted arcs, if any at all.The oscillation amplitude of the relative movement between the contact strips 15 and the contact wires 4, up to which electrical contact can be maintained between these contact partners, is measured via the transverse extent B of the surface structure 19 or the size of its projection S. The longitudinal extent L of the surface structure 19 can extend over the entire length of the contact strip 15 or be restricted to a smaller working range of the contact strip 15, within which the contact point between the contact strip 15 and the contact wire 4 can oscillate during ferry operation. In any case, the contact wire 4 slides along the surface structure 19 for each contact point.
[0029] The sheet-like structure 19 is partially bent by the contact wire 4 sliding along it as shown in FIG. 3 and FIG. 7 to FIG. 9, but due to its high flexural elasticity, it returns to its upright, for example flat, shape when the position of the contact point changes at the point left by the contact wire 4. The bending of the sheet-like structure 19 by the contact wire 4 preferably occurs locally at or around the contact point and, due to the low thickness of the sheet-like structure 19, does not generate any appreciable friction losses. The sheet-like structure 19 can, for example, be designed as a thin, soft and flexurally elastic film made of a material with high electrical conductivity, such as a metal alloy.A current flowing through the surface structure 19 when a gap occurs between the contact strip 15 associated with this surface structure 19 and a contact wire 4 has a low current intensity, since it can be assumed that electrical contact between other contact strips 15 and contact wires 4 continues. Furthermore, this condition typically only exists for a short time.
[0030] The sheet-like structure 19 can also be comb-like according to FIGS. 4 and 5 and have a back web 20 for fastening the sheet-like structure 19 to the contact strip 15 and a row of parallel, flexurally elastic filaments 21 projecting upwards from the back web 20. The filaments 21 of the sheet-like structure 19, which correspond to the teeth of a comb, can be formed by highly elastic wires, for example made of a super-elastic metal alloy such as nitinol or spring steel. The filaments 21 can also be formed by punching out filament spaces from a metal foil. A contact wire 4 sliding through such a sheet-like structure 19 only has to bend as many filaments 21 as its diameter requires, according to FIGS. 8 and 9. The filaments 21 are soft and elastic and have only a low spring return force.The filaments 21 are connected to the back web 20, which corresponds to a comb back and serves to fasten the sheet-like structure 19 to the grinding strip 15, for example to a grinding piece holder 23 carrying the grinding piece 22. The sheet-like structure 19 is preferably detachably connected to the grinding piece holder 23, for example by one or more screw connections 26 securing the back web 20 to the grinding piece holder 23 made of aluminum. The screw connections 26 are electrically conductive and enable a worn sheet-like structure 19 to be quickly replaced with a new one.
[0031] The contact piece holder 23 has, with respect to a vehicle longitudinal direction X, a front side 27 facing the direction of travel V of the road vehicle 1 and a rear side 28 facing away from the direction of travel V. The sheet-like structures 21 are connected to the contact piece holder 23 at the rear sides 28. Due to the rear fastening of a sheet-like structure 19 to the contact piece holder 23, the filaments 21 according to FIGS. 7 to 9 have free spring travel when bent by a contact wire 4 away from the contact piece 22, whereby the soft and elastic material properties of the filaments 21 can unfold undisturbed during bending.
[0032] According to FIGS. 7 to 9, the filaments 21 have a straight central section 24 and a curved end section 25, which for the sake of clarity are only provided with their reference symbols in FIG. 7. The straight central section 24 can extend parallel to a vehicle vertical direction Z, to which an end section 25 is connected which is slightly curved counter to the direction of travel V of the road vehicle 1, i.e. towards the rear. The curvature of the curved end section 25 allows a filament 21 to avoid the contact wire 4 by bending by the smallest possible deflection angle, as can be seen in particular from FIGS. 8 and 9.
[0033] According to FIG. 5, the filaments 21' can be designed as parallel, helically wound spring elements 29. Instead of, or in combination with, straight or slightly bent wire sections (FIG. 4), filaments 21' can also be wound in a helical line. Such a helical spring 29 is flexible and elastic and can also be made of a metal alloy with high electrical conductivity.
[0034] According to FIG 6, the sheet-like structure 19 can also be net-like and have knotless or knotted filaments 21''. The filaments 21'' of the sheet-like structure 19 can be braided, linked, woven, interlinked, knitted or the like in the manner of a plain weave or connected to one another in some other way. The filaments 21'' running towards the edge of the net-like sheet-like structure 19 can be fed back into the net to form a bow. The thickness of the filaments 21'' and the size of the mesh of the net are designed such that the sheet-like structure 19 is soft and flexible so that it can be bent locally by a contact wire 4. The network-like connected filaments 21 ' ' are made of an electrically conductive material in order to be able to carry current when gaps form between the contact strip 15 and the contact wire 4 due to vibrations of the pantograph 3.The surface structure 19 can be designed entirely as a net or can also have a foil-like back web 20 for attachment to the grinding piece holder 23.
Claims
Patent claims 1. A current collector (3) for an electrically or hybrid-electrically driven road vehicle (1), in particular a heavy commercial vehicle, for feeding traction energy from two contact wires (4) of a two-pole overhead line system, comprising - an adjustable support rod (6) which can be rotatably supported on the road vehicle (1) via a base joint (7) on the vehicle side and which carries two contact rockers (11) on the contact wire side, each rotatably connected via a rocker joint (10), - wherein on each contact rocker (11) at least one contact strip (15) extending in a vehicle transverse direction (Y) is resiliently mounted, wherein each contact strip (15) has a contact surface (16) facing upwards in a vehicle vertical direction (Z) for a sliding contact with a contact wire (4), characterized in that - that on at least one contact strip (15) of each contact rocker (11) there is arranged an electrically conductive, flexurally elastic sheet-like structure (19) with a longitudinal extent (L) and with a transverse extent (B) such that its longitudinal extent (L) extends in the vehicle transverse direction (Y) along the contact strip (15) and that its transverse extent (B) projects upwards over the contact surface (16) by an overhang (S) in the vehicle vertical direction (Z).
2. Current collector (3) according to claim 1, - wherein the sheet-like structure (19) is comb-shaped and has a back web (20) for fastening the sheet-like structure (19) to the grinding strip (15) and a row of parallel, flexurally elastic filaments (21) projecting upwards from the back web (20).
3. Current collector (3) according to claim 2, - wherein the filaments (21) have a straight central section (24) and a curved end section (25).
4. Current collector (3) according to claim 2, - wherein the filaments (21' ) are designed as parallel aligned helically wound spring elements (29).
5. Current collector (3) according to claim 1, - wherein the sheet-like structure (19) is formed in a net-like manner and has knotless or knotted filaments (21'').
6. Current collector (3) according to one of the preceding claims, - wherein a sheet-like structure (19) is detachably connected to a contact piece holder (23) carrying the contact piece (22).
7. Current collector (3) according to claim 6, - wherein the contact strip holder (23) has, with respect to a vehicle longitudinal direction (X), a front side (27) facing a direction of travel (V) of the road vehicle (1) and a rear side (28) facing away from the direction of travel (V), wherein the sheet-like structure (19) is connected to the contact strip holder (23) at the rear side (28).
8. Road vehicle (1), in particular a heavy commercial vehicle, comprising - an electric or hybrid-electric traction drive (2) and - a current collector (3) for feeding traction energy from two contact wires (4) of a two-pole overhead line system according to one of the preceding claims.