Motor vehicle, pantograph and procedure for operating a motor vehicle

Abstract

Motor vehicle (2), which is designed as an electric or hybrid vehicle and which has a pantograph (4) with two contacts (6), each for contacting a pole (12) of an overhead line (8) with a respective contact force (F), wherein the pantograph (4) is designed as a pantograph and has two contact arms (10), each of which is designed as a half-pantograph and on each of which one of the contacts (6) is attached, wherein the contacts (6) are coupled to each other via a weighing mechanism (28) to compensate for the contact forces (F).

Description

[0001] The invention relates to a motor vehicle, a pantograph and a method for operating a motor vehicle.

[0002] Motor vehicles are increasingly being equipped with electric drives to reduce or completely eliminate fuel consumption. An electric vehicle is powered exclusively by an electric motor, while a hybrid vehicle has both an electric motor and a combustion engine for alternative or combined propulsion.

[0003] Electrically powered vehicles are particularly interesting for freight transport. Freight transport by rail is tied to the rail network and therefore competes with the significantly more flexible freight transport by truck via the road network. Against this backdrop, the electrification of road freight transport is being pursued, so that vehicles would be supplied with energy and electrically powered via overhead lines along the road. Beyond freight transport, the electrification of road-based passenger transport, for example using electrically powered buses, is also of interest.

[0004] In DE 10 2011 076 620 A1 an electrically powered vehicle is shown which has a pantograph which can be swivelled laterally in order to maintain contact with the contact wires of an overhead line even when the vehicle is moving laterally.

[0005] US patent 2015 / 0380849A1 describes a current collector with contacts and a lever arm on which the contacts and a special parallelogram mechanism are arranged to generate a specific contact force.

[0006] Against this background, an object of the invention is to provide an improved motor vehicle, an improved pantograph for such a motor vehicle, and an improved method for operating a motor vehicle. The motor vehicle should be able to be connected to an overhead line as safely and reliably as possible by means of the pantograph, and should also be connected during operation.

[0007] The problem is solved according to the invention by a motor vehicle with the features of claim 1, by a pantograph with the features of claim 9, and by a method with the features of claim 10. Advantageous embodiments, further developments, and variants are the subject of the dependent claims. The descriptions relating to the motor vehicle apply mutatis mutandis to the pantograph and the method, and vice versa.

[0008] The motor vehicle is designed as an electric or hybrid vehicle and, accordingly, has an electric drive, i.e., an electric motor, for propulsion. The motor vehicle is not rail-bound and, as such, is designed for driving on a road. In the hybrid version, the motor vehicle also has an internal combustion engine. To supply energy to the electric drive, the motor vehicle has a pantograph with two contacts, each for contacting one pole of a, in particular, two-pole overhead line. The poles are typically wires, ropes, or cables running parallel to each other. The pantograph has a separate contact for each pole. The contact arms bridge, in particular, a vertical gap between the motor vehicle and the overhead line and are height-adjustable for this purpose.The overhead line generally runs along a road and in a longitudinal direction, which is also a direction of travel for the motor vehicle.

[0009] The pantograph is considered part of the motor vehicle insofar as it is mounted on it, for example by means of a suitable frame structure. The motor vehicle is preferably a truck with a driver's cab on or behind which the pantograph is mounted.

[0010] The current collector has two contact arms, each with one contact attached. The contacts are coupled to each other via a weighing mechanism to compensate for the contact forces, especially when there is a relative change in the contact forces between them.

[0011] The current collector is designed as a pantograph, and the contact arms are each designed as a half-pantograph. A pantograph is characterized in particular by a special lever mechanism for raising and lowering. Due to this lever mechanism, a pantograph is also referred to as a scissor current collector. Each half-pantograph has two arms, which are rotatably connected to each other by a hinge. One of the arms is a lower arm, which is rotatably attached to the vehicle body, for example, to a frame structure, via a base joint. When raising, the two arms unfold, i.e., are extended, so that the contact arm is raised to a specific height. To lower, the two arms are folded together, thereby reducing the height of the contact arm.In this case, this is achieved through the weighing mechanism for the two contact arms, each adjusted with respect to the contact force. The arms also conveniently form a guide for implementing a weighing mechanism similar to a platform scale, as described above.

[0012] The weighing mechanism therefore connects the contacts directly or indirectly to create a mechanical coupling of the contacts, which in operation leads to an automatic and dynamic adjustment of the contact forces through a redistribution between the contacts as required.

[0013] The weighing mechanism optimally distributes the contact forces between the two contacts, thus redistributing force between them. The contact forces are therefore balanced against each other and not independent of one another. The weighing mechanism is passive; no active control is involved.

[0014] The invention is based on the observation that, with multi-pole overhead lines, reliable contact between both poles is generally difficult when the contacts for the different poles are rigidly connected. An inclination of the pantograph relative to the overhead line can then lead to one of the contacts not receiving sufficient contact force and not making proper contact with the overhead line. To prevent this, the pantograph is divided into two independently movable contact arms. The two contact arms are height-adjustable separately, so that a height difference, for example due to poles hanging at different heights or due to uneven road surfaces, can be compensated for.

[0015] The problem, however, is that each contact must still be pressed against its respective pole with a specific contact force to ensure optimal contact. According to the invention, an optimal adjustment of the contact force is achieved by a weighing mechanism. This mechanism, similar to a balance scale, has a balance beam with two sides, also referred to as weighing sides. In a balance scale, a pan or similar object containing a weight is generally arranged on each side. The balance beam has a pivot point between the two sides, which is supported against a bearing. The current collector described here utilizes the principle underlying such a balance scale, namely that the balance beam automatically creates a force balance between the two weighing sides.In this system, the contacts correspond to the weighing pans and the poles to the weights. If, starting from an equilibrium state, one of the two poles is lifted relative to its corresponding contact due to unevenness, the weight force on that side is initially reduced, meaning the contact force is decreased. This side is relieved of the load, causing the balance beam on the other side to be pushed down by the pole there and the now greater load. The balance beam then rotates automatically around the point of application until the lifted pole is pressed back against its corresponding contact. Conversely, the same principle applies if one of the poles is pressed more strongly against the contact due to irregularities, thus increasing the contact force on one side. The contact force is therefore balanced on both sides of the weighing system. Preferably, the weighing mechanism is symmetrical, so that the contact force is set equally on both sides.

[0016] In a preferred embodiment, the weighing mechanism comprises a balance beam with a point of application on which the weighing mechanism is mounted. The two contacts are mounted on opposite sides of the point of application on the balance beam. The weighing mechanism is thus mounted, at least indirectly, to the vehicle via the point of application.

[0017] A further advantage of the invention is that the contact force can also be adjusted overall by additionally loading or unloading the balance beam at the point of application. In an advantageous embodiment, the current collector therefore has a drive for raising and lowering the contacts, and the drive transmits a driving force to the balance beam at the point of application to jointly adjust both contact forces. The respective contact force is thus adjusted by means of the drive. In the example described above, when the pole on one side is raised, part of the contact force is transferred from the other side to establish a force equilibrium. The contact force thereby decreases on both sides, resulting in an overall force loss. This is compensated for by the drive exerting an additional driving force on the balance beam, which offsets the force loss.Conversely, if the contact force is increased, the drive is retracted to relieve the load on the balance beam and reduce the overall contact forces, with the drive force then acting in the opposite direction, i.e., negatively. By design, the additional drive force is automatically and optimally distributed between both sides and both contacts by the weighing mechanism. The drive is advantageously controlled in such a way that a specific, predetermined contact force is applied to both sides.

[0018] Each contact is preferably designed as a sliding contact, in particular as a sliding strip, which runs transversely to the longitudinal direction of the overhead line, i.e., in a horizontal direction, thereby enabling contact over a specific width. A current collector configuration with two sliding contacts per contact is particularly suitable, with the two sliding contacts then arranged one behind the other in the longitudinal direction. Preferably, the contacts are each mounted on a rocker arm, which ensures that, regardless of the gradient of the overhead line, both contacts are pressed against the pole simultaneously. The rocker arm thus allows a rocking movement forwards and backwards with respect to the longitudinal direction. The rocker arm, in particular, forms an upper end of the contact arm.

[0019] Especially in connection with contact strips, but also more generally with contacts that are significantly wider than the poles, the problem arises that the contact force along the width of the contact depends on the exact contact position of the pole on the contact. Therefore, the weighing mechanism is preferably designed like a platform scale, where the contacts each form a support for the poles and are guided independently of the balance beam by means of a guide, so that the contact force of each contact is independent of the pole's point of contact on the contact. A platform scale is characterized in particular by the fact that the weighing pans, also called panels, are not guided exclusively by the balance beam, but additionally by a separate guide. For example, the guide is a pin or a rail along which the contacts, i.e., the weighing pans in general, can then move linearly.The guide is therefore specifically a forced guide, meaning that the movement of the contact is independent of the point where the balance beam attaches to that contact. As a result, the contact force is the same at every point on the contact.

[0020] In a practical design, the weighing mechanism includes a stop that limits the height difference between the two contacts to a maximum. This is based on the consideration that with separately height-adjustable contact arms, as described here, there is a risk that if the vehicle moves sideways and the contacts are extended to different heights, the higher of the two contacts will be pushed over the lower of the two poles, causing it to come into contact with the contact arm. This can potentially cause significant damage to both the overhead line and the vehicle. To prevent this, the height difference is limited by the stop. Therefore, when the contacts are extended to different heights, a height difference exists between them, which is limited by the stop.The stop thus prevents the contacts from moving further apart beyond the maximum height difference and provides an overall mechanical safety device. The stop is designed, for example, as a mechanical connection, such as a chain, rod, or belt, between the two contact arms. The maximum height difference is then determined by the maximum extension of the mechanical connection, at which point further movement of the contacts is blocked. Alternatively or additionally, the stop is designed as a stop for the balance beam on one or both of the contact arms and then limits the deflection of the balance beam.

[0021] In principle, a wide variety of configurations for the weighing mechanism are conceivable, particularly with regard to the connection of the contact arms or the contacts themselves via the balance beam. In a suitable configuration, each contact arm has a lower leg and an upper leg, which are rotatably connected relative to each other by means of a leg joint, and the weighing mechanism, especially the balance beam, connects the two lower legs. This allows for a vehicle-close arrangement of the weighing mechanism, thus providing optimal protection.

[0022] The contact arms are preferably fixed in a horizontal direction. In other words, the contact arms are not movable in the horizontal direction. Specifically, the contact arms for contacting the overhead line are only adjustable in a vertical direction, i.e., only in height, apart from any movement in the longitudinal direction that may occur when raising and lowering the contact arms due to their unfolding. "Horizontal" is also understood to mean "lateral," i.e., laterally with respect to the longitudinal direction and the vehicle. Such a pantograph with limited movement is particularly simple in design and requires minimal installation space. Compensation in the horizontal direction is achieved, in particular, by using sliding contacts of a suitable width.

[0023] Particularly in connection with the aforementioned design featuring a pantograph that is not horizontally movable, but also more generally, the vehicle expediently has a lane-keeping system to limit the vehicle's lane width. The lane-keeping system keeps the vehicle within a specific lane and prevents it from leaving it. The lane width is chosen to be narrow enough to prevent loss of contact due to the contacts sliding laterally off the overhead line.

[0024] The method serves to operate a motor vehicle as described above. The motor vehicle has a pantograph with two contacts, each for contacting one pole of an overhead line with a respective contact force, wherein the pantograph has two contact arms, on each of which one of the contacts is attached, wherein the contacts are coupled to each other via a weighing mechanism by means of which the contact forces are balanced.

[0025] The invention is not fundamentally limited to the described two-pole configuration with two contact arms. Rather, it also includes configurations with more than two separately driven contact arms in order to contact an overhead line with a correspondingly large number of poles, for example a three-phase overhead line or an overhead line with an additional pole for signal transmission.

[0026] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows the only Fig. 1. A schematic and partial view of a motor vehicle in a perspective view.

[0027] In Fig. Figure 1 shows a motor vehicle 2, which in this case is a truck. The motor vehicle 2 is designed as an electric or hybrid vehicle and has a pantograph 4 for power supply, with two contacts 6 for contacting a two-pole overhead line 8. The pantograph 4 has two contact arms 10, on each of which one of the contacts 6 is attached, for contacting one pole 12 of the overhead line 8. In the illustrated embodiment, each contact 6 has two sliding contacts 14, which are arranged one behind the other in the longitudinal direction L of the overhead line 8. The pantograph 4 is mounted above and longitudinally L behind a driver's cab 16 of the motor vehicle 2.

[0028] In the present embodiment, the current collector 4 is designed as a pantograph, so that the contact arms 10 are each designed as a half-pantograph. Each contact arm 10 has two legs 18, 20: a lower leg 18, which is rotatably attached to the body of the vehicle 2 via a base joint 22, and an upper leg 20, which is rotatably attached to the lower leg 18 via a leg joint 24. The two legs 18, 20 are rotatable together about a base axis D1 by means of the base joint 22. The two legs 18, 20 are rotatable relative to each other about a knee axis D2 by means of the leg joint 24. When raised, the two legs 18, 20 unfold, i.e., are extended, so that the contacts 6 are each extended to a specific height H. To lower the device, the two legs 18, 20 are folded together, thereby reducing the height H of the contacts 6.Additionally, the two sliding contacts 16 are mounted on a respective contact arm 10 by means of a rocker 26, which allows a rocking movement forwards and backwards. The contact arms 10 are fixed in a horizontal direction R1 and adjustable only in a vertical direction R2, i.e., only in height.

[0029] The contacts 6 are each pressed against the poles 12 with a contact force F. To compensate for irregularities in the contact forces F, the contacts 6 are coupled to each other via a weighing mechanism 28. This ensures that a force balance is automatically achieved when the contact forces F change relative to each other. The weighing mechanism 28 thus connects the contacts 6 and establishes a mechanical coupling, which leads to an automatic and dynamic adjustment of the contact forces F during operation. The sum of the contact forces F is optimally distributed between the two contacts 6 by the weighing mechanism 28.

[0030] The weighing mechanism 28, similar to a balance scale, has a balance beam 30 with two sides, also referred to as weighing sides. In a balance scale, a weighing pan or similar component is generally arranged on each side, in which a weight is placed. Between the sides, the balance beam 30 has a pivot point 32, which is supported against a bearing, in this case the structure behind the driver's cab 16. The pantograph 4 utilizes the fact that the balance beam 30 automatically creates a force balance between the two sides. If the load on the corresponding contact 6 changes on one side, the balance beam 30 is rotated around the pivot point 32 until the corresponding pole 12 is pressed against the corresponding contact 6 again. The contact force F is thus balanced on both sides.

[0031] In addition, the current collector 4 in the illustrated embodiment therefore has a drive 34 for raising and lowering the contacts 6, i.e., also for extending and retracting the current collector 4 as a whole. The drive 34 is, for example, an electric motor or a pneumatic drive. The drive 34 transmits a drive force A to the balance beam 30 at the point of application 32, for the joint adjustment of both contact forces F. By design, this additional drive force A is also automatically and optimally distributed to both sides and thus to the two contacts 6 by the weighing mechanism 30.

[0032] Furthermore, in the illustrated embodiment, the weighing mechanism 30 is designed in the manner of a platform scale. The contacts 6 each form a support for the poles 12 and are guided independently of the balance beam 30 by means of a guide, so that the contact force F of each contact 6 is independent of the point of contact of the pole 12 on the contact 6. The guide is realized here by the legs 18, 20. Moreover, the guide is a positive guide, so that the movement of each contact 6 is independent of the point of attachment of the balance beam 30 to that contact 6.

[0033] As a result, the contact force F is then the same at every point of contact 6.

[0034] In this case, the height difference dH between the two contacts 6 is limited to a maximum height difference. This is achieved by a stop 36. This is located in Fig.1 each attached to the lower leg 18 of the contact arms 10 and thus limits the deflection of the balance beam 30, thus preventing an excessive deflection.

Claims

[1] Motor vehicle (2) which is designed as an electric or hybrid vehicle and which has a pantograph (4) with two contacts (6), each for contacting a pole (12) of an overhead line (8) with a respective contact force (F), wherein the pantograph (4) is designed as a pantograph and has two contact arms (10) which are each designed as a half-pantograph and on which one of the contacts (6) is attached, wherein the contacts (6) are coupled to each other via a weighing mechanism (28) to compensate for the contact forces (F). [2] Motor vehicle (2) according to the preceding claim, characterized by , that the weighing mechanism (28) has a balance beam (30) with a point of application (32) on which the weighing mechanism (28) is mounted, and that the two contacts (6) are mounted on opposite sides of the point of application (32) on the balance beam (30). [3] Motor vehicle (2) according to any one of the preceding claims, characterized by , that the current collector (4) has a drive (34) for raising and lowering the contacts (6), and that the drive (34) transmits a driving force (A) to the balance beam (30) at the point of application (32) for the joint adjustment of both contact forces (F). [4] Motor vehicle (2) according to any one of the preceding claims, characterized by , that the weighing mechanism (28) is designed in the manner of a platform scale, wherein the contacts (6) each form a support for the poles (12) and are each guided independently of the balance beam (30) by means of a guide, so that the contact force (F) of a respective contact (6) is independent of a contact point of the pole (12) on the contact (6). [5] Motor vehicle (2) according to any one of the preceding claims, characterized by , that the weighing mechanism (28) has a stop (36) which limits a height difference (dH) between the two contacts (6) to a maximum height difference. [6] Motor vehicle (2) according to any one of the preceding claims, characterized by , that each contact arm (10) has a lower leg (18) and an upper leg (20) which are rotatably connected relative to each other by means of a leg joint (24), and that the weighing mechanism (28) connects the two lower legs (18) together. [7] Motor vehicle (2) according to any one of the preceding claims, characterized by that the contact arms are fixed in a horizontal direction. [8] Motor vehicle (2) according to any one of the preceding claims, characterized by that it has a lane keeping system to limit the width of a lane. [9] Current collector for a motor vehicle (2) according to one of the preceding claims, which is designed as a pantograph and which has two contacts (6), each for contacting a pole (12) of an overhead line (8) with a respective contact force (F), and with two contact arms (10), each of which is designed as a half-pantograph and on each of which one of the contacts (6) is attached, wherein the contacts (6) are coupled to each other via a weighing mechanism (28) to compensate for the contact forces (F). [10] Method for operating a motor vehicle (2) according to one of claims 1 to 8, wherein the motor vehicle (2) has a pantograph (4) with two contacts (6), each for contacting a pole (12) of an overhead line (8) with a respective contact force (F), wherein the pantograph (4) is designed as a pantograph and has two contact arms (10), each of which is designed as a half-pantograph and on each of which one of the contacts (6) is attached, wherein the contacts (6) are coupled to each other via a weighing mechanism (28) by means of which the contact forces (F) are balanced.

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