pantograph and a road vehicle equipped with one

Abstract

The invention relates to a pantograph (3) for a road vehicle (1) with an electric traction drive (2) for supplying traction energy from an overhead line system. It comprises an erectable support frame (6) which can be rotatably supported on the road vehicle (1) via a base joint (7) on the vehicle side and carries two contact rockers (11) rotatably connected via a rocker joint (10) on the contact wire side. Each of the contact rockers (11) carries at least one contact strip (15) extending in a transverse direction (Y) of the vehicle, which has a contact element holder (16) and an electrically conductive contact element (17) mounted therein with a contact surface (18) for a contact wire (4) resting on the contact strip (15). The sliding strips (15) of each of the contact rockers (11) can be electrically connected to a traction drive (2) via power cables (26) laid along the support rod (6).By routing a power cable (26) along the support rod (6) to each contact rocker (11), which branches into several connecting cables (23) in the area of ​​the respective contact rocker (11) to each of the at least one slip ring (15), each of which is electrically connected to the contact piece holder (16) of this slip ring (15) at a connection point (22), the wear of the contact pieces (17) can be reduced.

Description

[0001] The invention relates to a current collector having the features specified in the characterizing part of patent claim 1.

[0002] Such a pantograph designed as a pantograph and a motor vehicle equipped with it are known from the published patent application DE 10 2021 208 951 A1. To supply electricity to such vehicles, direct current fed overhead line systems are provided, the overhead lines of which are arranged above electrified lanes and are electromechanically contacted by the vehicle with the help of the extended pantograph. The pantograph comprises a main frame with switch boxes for the traction voltage and the control. It comprises an arm construction made up of lower and upper arms that are rotatably connected to one another via arm joints, with the lower arm being mounted on the main frame via a lower arm bearing. An upper arm carries a rocker with a rocker support that is rotatably connected to the upper arm via a rocker joint and carries contact strips.A traction current cable is routed from a connection point on the contact strip to the traction voltage switch box and / or to the motor vehicle.

[0003] In particular, the contact pieces of contact strips of such pantographs are subject to wear in the form of abrasion of the contact piece material due to sliding contact with the contact wire, as well as in the form of breakages from the contact surface of the contact piece due to sudden contact between the contact strips and the contact wire. The latter can be caused by the pantograph being raised too quickly or by vertical oscillating movements of the contact rockers relative to the contact wire, which can be triggered by the vehicle's deflection due to uneven road surfaces or acceleration maneuvers.

[0004] To solve the wear problem, it is known from the published patent application DE 10 2020 207 959 A1 to arrange a vibration absorber at the contact wire-side end of the pantograph support frame, which is designed to dampen vertical vibrations of the support frame and the rocker arrangement introduced by the vehicle.

[0005] Furthermore, it is known from the published patent application DE 10 2021 207 709 A1 to reduce the inflow cross-section in an air supply line of the lifting device of a pantograph when lifting the rocker assemblies depending on a vertical position of the rocker assemblies in order to prevent the contact strips from striking the contact wires too quickly.

[0006] However, the solutions mentioned from the state of the art are not yet able to solve the wear problem mentioned satisfactorily.

[0007] The invention is therefore based on the object of providing a current collector of the type mentioned at the outset with improved wear behavior.

[0008] The object is achieved according to the invention by a current collector having the features mentioned in patent claim 1.

[0009] The invention is based on a current collector for an electrically or hybrid-electrically powered road vehicle, which may, for example, be a heavy commercial vehicle such as a semitrailer tractor. The current collector is designed and provided for feeding traction energy from two contact wires of a two-pole overhead line system. The current collector comprises an erectable support rod, which can be rotatably supported on the road vehicle via a base joint on the vehicle side and carries two contact rockers on the contact wire side, each rotatably connected via a rocker joint. Each of the contact rockers carries at least one contact strip extending in a transverse direction of the vehicle, which contact strip has a contact piece holder and an electrically conductive contact piece mounted therein, having a contact surface for a contact wire resting on the contact strip.The contact strips of each of the contact rockers can be electrically connected to a traction drive via power cables laid along the support rods.

[0010] According to the invention, a power cable is laid along the support rod for each contact rocker, which branches or splits into two or more connecting cables in the area of ​​the respective contact rocker for each of the at least one contact strip. The splitting takes place at a distribution point, which can be attached to the contact rocker via an insulator. The connecting cables leading to the at least one contact strip are each electrically connected to the contact piece holder of this contact strip at a connection point. Because the traction current flowing into the contact strip via a contact wire flows out of it via several connecting cables, the electrical current is distributed among the several connection points, which are heated correspondingly less due to the lower current intensity. The lower heating, in turn, reduces wear on the contact pieces.Two, three, four, or more connection points can be provided on the contact piece holders per contact strip. The number of connection points can be determined depending on the cross-section and length of a contact piece, as well as the nominal value of the selected traction voltage.

[0011] In a further advantageous embodiment of the current collector according to the invention, the multiple connection points are arranged symmetrically to a center with respect to a length of the contact piece on the contact piece holder with respect to a vehicle transverse direction. This further optimizes the reduction in heating of a contact piece due to electrical heat if the connection points are suitably spaced from one another. Thus, an arrangement of the connection points symmetrical to the center of the contact strip is advantageous. During normal driving operation, only part of the length of the contact piece is ground by the contact wire. The contact point between the contact wire and the contact surface only moves within a working range of the contact piece, which utilizes only approximately 50% to 75% of the contact piece length, in order to avoid the risk of the contact wire slipping sideways off the contact strip via an end horn.It has therefore proven advantageous to distribute the connection points symmetrically over the working area of ​​the contact piece.

[0012] In a further advantageous embodiment of the current collector according to the invention, the multiple connection points are arranged along a working area of ​​the contact piece on the contact piece holder in such a way that the distances between adjacent connection points and the distances between terminal connection points and the end of the working area are equal. This distance can be approximately one-third of the working area length for two connection points, approximately one-quarter for three connection points, approximately one-fifth for four connection points 22, and so on. This achieves a maximum distance between the connection points, which keeps the generated current heat as low as possible. This also reduces the associated wear on the contact pieces.

[0013] 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 for supplying traction energy according to one of the preceding claims.

[0014] 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 Fig. 1 a road vehicle according to the invention in side view, Fig. 2 the road vehicle from Fig. 1 in front view, Fig. 3 a variant of the contact strip of the current collector according to the invention is schematically illustrated.

[0015] According to Fig. 1 and Fig. 2 comprises a road vehicle 1 according to the invention, which may be a heavy commercial vehicle, such as a tractor unit, an electric or hybrid-electric traction drive 2, and a current collector 3 according to the invention for supplying 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 are arranged 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.

[0016] The pantograph 3 comprises according to Fig. 1 and Fig. 2 an erectable support rod 6 with one end on the vehicle side and one end on the contact wire side, opposite the contact wire side. The support rod 6 is rotatably supported on the road vehicle 1 via a base joint 7, wherein the base joint 7 is mounted on a main frame 9 of the pantograph 3 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 and arranged next to one another as seen in a vehicle longitudinal direction X. In the illustrated embodiment, the support rod 6 is designed like a pantograph and has a lower arm 12 and two upper arms 14 connected to it 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 contact strips 15 extending in a vehicle transverse direction Y are resiliently mounted, for example via leaf springs 21.The two contact strips 15 of a contact rocker 11 are arranged one behind the other as seen in the vehicle's longitudinal direction X.

[0017] Each of the contact strips 15 has, according to Fig. 1 to Fig. 3 has a contact piece holder 16 and an electrically conductive contact piece 17 mounted therein. Each contact piece 17 comprises a contact surface 18 which, viewed in a vehicle vertical direction Z, faces upwards for a sliding contact with a contact wire 4 of the overhead line system. A lifting device 19, 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 20 of the road vehicle 1. 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 resting on the contact strips 15.

[0018] Due to the traction voltage applied between the two contact wires 4, traction current then flows from one of the two contact wires 4 via the contact piece 17 contacting it and its contact piece holder 16 to connection points 22, to which connecting cables 23 are electrically connected to the contact piece holder 16. All connecting cables 23 of a contact rocker 11 are routed to a distribution point 24 of the contact rocker 11, which is supported on the contact rocker 11 via an electrical insulator 25. From the distribution contact 24, a power cable 26, which is laid along the support rod 6, leads into the main frame 9 and from there to the traction drive 2 or other electrical devices of the road vehicle 1 to be supplied, such as an energy storage device. The specific interconnection with other electrical components of the road vehicle 1 will not be discussed in detail, as this is known per se.The traction current then leads from the traction drive 2 along the corresponding path back via power cables 26 leading to the other contact rocker 11 to the distribution point 24 there, via connecting cables 23 to connection points 22 on the contact piece holders 16 and through the contact pieces 17 of this other contact rocker 11 into the other of the two contact wires 4.

[0019] At the contact points 27 between contact pieces 17 and contact wires 4, heating occurs during the transmission of electrical traction energy both due to the sliding friction between the underside of the contact wire 4 and the contact surface 18 of the contact piece 17, which comprises graphite, and due to the electrical heat of the traction current. This leads to wear on the contact piece 17 in addition to the mechanical abrasion caused by the contact wire 4. According to the invention, several connection points 22 are arranged on the contact piece holders 16 for each contact strip 15, which leads to a significant reduction in contact piece heating. The invention is based on the finding that the area around the current contact point 27 is not the hottest area of ​​the contact piece 17, but rather the area around the connection point 22.This was confirmed by thermal images of the contact strips 15 in operation, on which the contact point 27, viewed in the vehicle's transverse direction Y, was spaced from the connection point 22 due to lateral movements of the road vehicle 1 within its lane and / or due to zigzag paths of the contact wires 4 relative to a lane center. As the traction current flowing into the contact strip 15 via a contact wire 4 flows out of it via several connecting cables 23, the electrical current is distributed across several connection points 22, which are heated correspondingly less due to the lower current intensity. This lower heating, in turn, reduces wear on the contact pieces 17.

[0020] According to Fig. 1 and Fig. 2, two connection points 22 are provided on the contact piece holders 16 for each contact strip 15, while according to Fig. 3 three connection points 22 are arranged on the contact piece holder 16. Four connection points 22 per contact strip 15 are also conceivable, and more than four connection points 22 are not excluded. The number of connection points 22 can be selected depending on the cross-section and length L of a contact piece 17 as well as on the nominal value of the traction voltage. Further optimization of the heating reduction of a contact piece 17 due to electrical heat is achieved if the connection points 22 are suitably spaced from one another. Thus, an arrangement of the connection points 22 symmetrical to the center of the contact strip 15 is advantageous.During normal operation, only a portion of the length L of the contact piece 17 is contacted by the contact wire 4; this means that the contact point 27 between the contact wire 4 and the contact surface 18 only moves within a working area D which only uses approximately 50% to 75% of the contact piece length L in order to avoid the risk of the contact wire 4 slipping laterally over an inner end horn 28 or an outer end horn 29 from the contact strip 15. It has therefore proven advantageous to distribute the connection points 22 evenly over the working area D of the contact piece 17. The distance d between two directly adjacent connection points 22 and between an edge-side connection point 22 and the end of the working area D adjacent to it can be approximately one third (as in . Fig. 2), with three connection points 22 about a quarter (as shown in Fig.3), with four connection points 22, approximately one fifth of the working area length D, and so on. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 208 951 A1

[0002] DE 10 2020 207 959 A1

[0004] DE 10 2021 207 709 A1

[0005]

Claims

[1] Pantograph (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 erectable 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 each of the contact rockers (11) carries at least one contact strip (15) extending in a vehicle transverse direction (Y), which has a contact piece holder (16) and an electrically conductive contact piece (17) mounted therein with a contact surface (18) for a contact wire (4) resting on the contact strip (15), and - wherein the contact strips (15) of each of the contact rockers (11) can be electrically connected to a traction drive (2) via power cables (26) laid along the support rod (6), characterized by , - that for each contact rocker (11) a power cable (26) is laid along the support rod (6), which in the area of ​​the respective contact rocker (11) branches into two or more connecting cables (23) to each of the at least one contact strip (15), - wherein the connecting cables (23) leading to the at least one contact strip (15) are each electrically connected at a connection point (22) to the contact piece holder (16) of this contact strip (15). [2] Current collector (3) according to claim 1, - wherein the plurality of connection points (22) are arranged symmetrically to a center with respect to the length (L) of the contact piece (17) on the contact piece holder (16) with respect to a vehicle transverse direction (Y). [3] Current collector (3) according to claim 1 or 2, - wherein the plurality of connection points (22) are arranged along a working area (D) of the contact piece (17) on the contact piece holder (16) in such a way that the distances (d) between respectively adjacent connection points (22) and the distances (d) between terminal connection points (22) and the end of the working area (D) are equal. [4] 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.

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