Railroad car bogie and railroad car

Abstract

The present disclosure relates to a bogie for a rail vehicle guided over a rail track, comprising a base configured to be mounted on a chassis of the rail vehicle, a frame rotatably arranged relative to the base about a vertical steering axis, and two wheels each having a tread rotatably arranged relative to the frame about a respective wheel rotation axis, the two wheels being laterally spaced apart from one another and the steering axis being disposed laterally between the two wheels. The bogie further comprises at least one sensor assembly configured to measure, during operation, the lateral position of the tread relative to the rail track.

Description

[Technical field]

[0001] The present disclosure relates to a bogie for a rail vehicle, a rail vehicle including such a bogie, and a method for steering a bogie of a rail vehicle. [Background technology]

[0002] Rail vehicles coupled to rail tracks, such as trains, trams, or other vehicles, often exhibit less than optimal alignment of the wheels with respect to the track, which leads to higher friction between the rail track and the wheel treads. This contact results in profile wear and increased noise pollution, especially in curves with small radii. In the case of low-floor vehicles, this effect is even more pronounced. Low-floor vehicles have smaller wheels and fewer wheels per car in order to increase passenger comfort and interior space of the vehicle by having a continuous low-floor structure. However, this also leads to increased loads per wheel and more pronounced fatigue of the wheel material, causing small cracks or even larger material failures.

[0003] Furthermore, reducing the number of wheels per vehicle and / or per vehicle bogie reduces the suspension comfort for passengers of the vehicle and / or vehicle with the bogie. Particularly in low-floor vehicles, this leads to a conflict between interior space requirements and suspension comfort requirements. Furthermore, creating the desired suspension comfort for passengers traditionally requires elaborate suspension concepts located above the bogie and between the bogie and the vehicle. This consumes a lot of construction space and further reduces the interior space available for passengers.

[0004] Several attempts to reduce track and wheel wear are known. In the 1990s, systems were developed that allowed the wheels to be steered in curves. However, these solutions often proved to suffer from undesirable side effects on straight track sections, such as the wheels sticking to the track on one side of the tread, leading to increased wear and noise on straight track sections. Therefore, after a few years, most of these concepts were abandoned and traditional concepts combined with wheel noise absorbers and advanced industrial lubricants were promoted again.

[0005] One example of a rail bogie that successfully addresses these disadvantages is US Pat. No. 5,399,233, published in 2018 in the name of the same applicant. The vehicle disclosed comprises a wheel assembly interconnected to a chassis, as well as a method for steering said vehicle. The wheel assembly comprises a cross member having a first end, to which a first hub is interconnected by a first steering joint, and a second end, to which a second hub is interconnected by a second steering joint. A first wheel is mounted to the first hub rotatably about a first axis of rotation, and a second wheel is mounted to the second hub rotatably about a second axis of rotation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018015290 Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure aims to provide a bogie for a rail vehicle, a rail vehicle including the bogie, and a method for steering a bogie of a rail vehicle. In particular, it is an object of the present disclosure to provide a bogie for a rail vehicle, a rail vehicle including the bogie, and a method for steering a bogie of a rail vehicle that does not have at least some of the disadvantages of the prior art.

[0008] According to the present disclosure, these objects are addressed by the features of the independent claims. Furthermore, further advantageous embodiments can be seen from the dependent claims and the description.

[0009] The present disclosure specifies a bogie for a rail vehicle running on a rail track. The bogie typically comprises a base configured to be mounted or integrated into the chassis of the rail vehicle. The bogie further comprises a frame rotatably arranged relative to the base about a vertical steering axis and two wheels each including a tread rotatably arranged relative to the frame about a respective wheel rotation axis, the two wheels being arranged laterally spaced apart from each other (essentially coaxial). The steering axis is arranged laterally between the two wheels. The two wheels of the bogie are typically mounted rotatably and, if appropriate, deflectable against the force of at least one spring of the suspension, and fixed to the bogie with respect to the other degrees of freedom. In a preferred variant, the wheels are arranged substantially coaxially with respect to a common wheel rotation axis. The bogie further comprises at least one sensor assembly configured to measure, during operation, the lateral position of the tread of at least one of the two wheels relative to the rail track.

[0010] In a variation of the present disclosure, the base is disposed on the frame via a rotatable bearing or bearing assembly. One rotatable surface of the bearing may be disposed on the base and the other rotatable surface of the bearing or bearing assembly may be disposed on the frame. The bearing or bearing assembly allows rotation between the base, which is connected during operation to the railcar chassis, and the frame of the bogie.

[0011] A steering axle is located laterally between the two wheels, which are rotatable but quasi-statically arranged relative to each other, making it possible to steer the wheels while in operation on a railroad track by rotating the frame about the steering axle. Both wheels are located on the frame and rotate simultaneously when necessary, without the need to steer them independently.

[0012] The lateral position of the tread of at least one of the two wheels is measured during operation by a sensor assembly. The lateral position of the tread relative to the wheel determines which area of ​​the rolling surface of the tread is in contact with the railroad track during operation. Noise pollution is usually caused by the bogie of a rail vehicle during operation when the lateral position of the tread relative to the wheel is not desirable. For example, the tread flanges may contact the railroad track in tight curves, which causes noise pollution and increases wear. The lateral position measurement is usually required to control the lateral position of the tread relative to the railroad track.

[0013] In a variant of the disclosure, each of the wheel rotation axes is substantially arranged coaxially with respect to each other and perpendicular to the steering axis. The wheel rotation axes of the two wheels are arranged, for example, parallel to the lateral direction. In this case, the wheel rotation axes are also automatically arranged parallel to each other and perpendicular to the steering axis. In a further variant of the disclosure, each of the wheel rotation axes is substantially arranged coaxially with respect to each other. During driving, the respective wheel rotation axes may be independently deflected, for example by independent wheel suspensions. In that case, during driving, the wheel rotation axes are not always exactly arranged coaxially. In a neutral state without any deflection, the wheel rotation axes of both wheels are arranged coaxially with respect to each other.

[0014] The at least one sensor assembly preferably comprises a forward sensor arranged in front of the respective wheel and / or a rearward sensor arranged behind the respective wheel with respect to the travel direction of the bogie. The travel direction is the direction of movement of the bogie during travel along the railway track. The travel direction of the bogie may change during travel. This means that the aforementioned forward sensor becomes a rearward sensor and vice versa. The forward sensor may be arranged in front of the respective tread and the rearward sensor may be arranged behind the respective tread. The sensor assembly measures the lateral position of the respective tread with respect to the railway track during travel, for example using a forward and / or rearward sensor of one wheel and / or a forward and / or rearward sensor of the other wheel. Preferably, four sensors are used. The use of two or more sensors increases the accuracy of the measurement of the lateral position of the tread with respect to the railway track, especially in tight curves.

[0015] Advantageous suspension properties of the bogie can be realized if each wheel is attached to the frame by a swing arm, which is pivotable relative to the frame about a pivot axis against the force of a swing arm spring. In other words, the swing arm is arranged to be pivotable relative to the frame about a pivot axis, and the swing arm spring limits and slows down the swinging movement of the swing arm relative to the frame. The swing arm combined with the swing arm spring is subjected to high frequency vibrations coming from the railroad track during operation.

[0016] The pivot axis of the swing arm is preferably arranged parallel to the respective wheel rotation axis, and even more preferably, the pivot axis is arranged in front of or behind the respective wheel rotation axis relative to the travel direction of the bogie, which advantageously results in a compact construction.

[0017] In a variant, the swingarm has a fork-like shape. The fork-like shape is formed by two parts extending generally in the direction of travel and one lateral part extending generally laterally and connecting the other two parts. Preferably, one longitudinal end of the two parts is connected to the frame via a pivot shaft and the other longitudinal end of the two parts is connected to the lateral part, thereby forming the fork-like shape. More preferably, the lateral part comprises a spring seat arranged to hold the swingarm spring. The spring seat is one contact point of the swingarm spring. The frame comprises another spring seat as a second contact point of the swingarm spring.

[0018] An advantageously compact construction can be achieved if, relative to the travel direction of the bogie, the pivot axis is arranged ahead of the wheel rotation axis and the swing arm spring is arranged behind the wheel rotation axis, whereby each wheel is at least partially surrounded by a swing arm. For a compact and stable construction, it is further preferred that each wheel is attached to two parts of a swing arm extending in the travel direction.

[0019] Particularly good suspension effects can be achieved if the swingarm spring is or includes a rubber-composite spring or a rubber-metal composite spring, which advantageously reduces noise pollution and unwanted vibrations. A rubber-metal composite spring may include a metal structure surrounded by rubber.

[0020] In a variation of the present disclosure, the sensor assembly is at least partially disposed on the frame or swing arm, in other words, at least some portion of the sensor assembly can be disposed on the frame or swing arm or a combination thereof.

[0021] In a variant, the front and / or rear sensors of the sensor assembly are interconnected to the frame or swingarm by a sensor bracket. The sensor bracket is, for example, part of the sensor assembly or part of the frame that positions the front and / or rear sensors in a predefined position, preferably in front of the tread or behind the tread. The sensor bracket provides an advantageously simple and reliable solution for holding the respective sensors in place.

[0022] In a preferred variant, the front and / or rear sensors of the sensor assembly are arranged to be vertically displaceable during operation in order to adjust the vertical distance of the respective sensor relative to the railroad track. Undesirable vertical displacement of at least one of the sensors may occur due to frame movements and / or swing arm movements. Undesirable vertical displacement may also be caused by wheel wear, which reduces the radial extension of the wheel. Arranging the respective sensors to be vertically displaceable makes it possible to compensate for undesirable vertical displacement of the respective sensor.

[0023] A reliable and simple solution for adjusting the vertical distance of the front and / or rear sensors of each sensor assembly is to provide at least one leveling actuator on each sensor assembly configured to adjust the vertical distance of the front and / or rear sensors during travel. In another variation, each sensor may be provided with one leveling actuator configured to adjust the vertical distance during travel. In another variation, multiple sensors have one associated leveling actuator.

[0024] A particularly advantageous solution for adjusting the vertical distance of the front and / or rear sensors of the respective sensor assembly is to arrange the sensor bracket pivotally about a levelling axis relative to the swing arm or relative to the frame. In this variant, the sensor bracket is arranged on the swing arm or on the frame. The levelling axis is arranged, for example, parallel to the respective wheel rotation axis. If the sensor bracket is arranged on the swing arm, the sensor bracket with the respective sensor follows the swinging movement of the swing arm relative to the frame. Arranging the sensor bracket pivotally relative to the swing arm makes it possible to compensate for the swinging movement of the sensor bracket and thereby to hold the respective sensor in a predetermined position even during the swinging movement of the swing arm. In a variant, at least one levelling actuator is connected to the pivotable sensor bracket and is configured to adjust the vertical position of the respective sensor during travel.

[0025] To achieve an advantageous detection result, the at least one front sensor and / or the at least one rear sensor are arranged on the sensor assembly such that the detection direction is oriented perpendicularly from the bogie to the railway track, which according to this variant is parallel to the vertical direction and parallel to the steering axis. Movements that displace the front sensor, the rear sensor and / or the sensor bracket such that the detection direction of the respective sensor is not oriented vertically can be compensated by at least one leveling actuator.

[0026] The at least one forward sensor and / or the at least one rearward sensor may be an inductive sensor, a laser sensor, a capacitive sensor, an ultrasonic sensor, an optical sensor, a radar sensor, or a combination thereof. Inductive sensors usually obtain good results even if the railroad track is dirty and / or under snow.

[0027] It is particularly easy to steer the frame if the bogie comprises a steering actuator, which is connected to the frame and is configured to rotate the frame about a steering axis by a steering angle relative to the base during operation. The steering actuator is, for example, coupled to the base and to the frame and allows the rotation of the frame relative to the base. In another variant, the steering actuator may be directly coupled to the chassis of the rail vehicle.

[0028] To control the movement of the bogie, the bogie may comprise an electric engine for each wheel, which is arranged to drive the corresponding wheel during operation. The electric engine may for example be arranged coaxially with respect to the wheel and on the same shaft as the wheel. The electric engine may be arranged on the outer side of the wheel, in order to achieve a particularly compact construction. The electric engine is preferably an in-hub traction motor. Furthermore, the driving during operation comprises accelerating the respective wheel by the electric engine or decelerating the respective wheel. The electric engine can thus function as a motor brake for braking the respective wheel. For example, the motor brake is preferably the main brake of the railway bogie. It is also conceivable that one electric motor is controlled to accelerate and the other electric motor arranged on the opposite side of the bogie is controlled to decelerate (or accelerate slowly) for steering the railway bogie around the steering axis, in order to do so in a particularly quiet manner. The electric engine may furthermore be used for regenerative braking for recovery of energy stored in the respective battery.

[0029] It is further preferred that the electric engine is the only brake of the railway bogie, which is arranged to slow down the railway bogie during its travel. In this embodiment, the railway bogie does not comprise standard mechanical brakes, such as disc brakes. This brake-free embodiment provides a solution for simple braking of the railway bogie. The railway bogie of this variant may further comprise a capacitor bank, which supplies electrical energy to the electric engine for braking in case of failure of the standard electrical system of the railway bogie or of the railway vehicle. Furthermore, the bogie may comprise brakes arranged to slow down the corresponding wheels during travel. The brakes are for example disc brakes, preferably internally ventilated disc brakes, the discs of which may for example be arranged coaxially with respect to the wheels and on the same shaft as the wheels. The discs of the disc brakes may be arranged on the outer lateral sides of the electric engine, in order to achieve a particularly compact construction.

[0030] In order to achieve an advantageously compact construction, the brake caliper of the disc brake may be arranged fixedly on the swing arm, preferably on one of two of the portions of the swing arm extending in the direction of travel.

[0031] Advantageously simple and reliable steering of the bogie can be achieved if the bogie further comprises a control configured to receive the lateral positions measured during travel and configured to determine a steering angle based on the received lateral positions. The control is further configured to control the steering actuator based on the determined steering angle. Furthermore, additionally or alternatively, the control is configured to control at least one electric engine and / or at least one brake to rotate the frame about a steering axis relative to the base based on the determined steering angle. The desired steering of the bogie is achieved according to this variant by controlling the steering actuator and / or by controlling the electric engines and brakes of the wheels. The electric engines and brakes of the wheels can be controlled during travel such that steering of the bogie is achieved. For example, one wheel decelerates and the other wheel accelerates, thereby rotating the bogie relative to the base. The control may be located on or in the bogie. In another variant, the control is located outside the bogie, for example in the rail car.

[0032] The steering of the bogie can be a steering actuator, an electric engine and brakes, and / or a steering actuator combined with an electric engine and brakes.

[0033] In a variant of the disclosure, the frame comprises a base frame and a wheel frame interconnected to each other via a spring-damping device, the base being arranged on the base frame and the wheels being arranged on the wheel frame. Preferably, a swing arm is arranged on the wheel frame and interconnects the wheels with the wheel frame. Interconnecting the base frame and the wheel frame via a spring-damping device makes it possible to damp vibrations and movements coming from the chassis of the rail vehicle during operation and also to damp vibrations coming from the rail track. This variant of the disclosure advantageously increases the comfort of the suspension of the bogie during operation.

[0034] In a variant, the spring-damping device comprises a plurality of dampers and a plurality of spring assemblies, each of which comprises a first spring and a second spring arranged coaxially with respect to one another. The spring assemblies are preferably arranged at corners of the frame. The first spring and the second spring have different spring characteristics, which increases the range of frequencies that can be absorbed by the spring-damping device during travel compared to a single spring. The spring assemblies are preferably arranged substantially vertically between the base frame and the wheel frame. At least some of the dampers may be arranged next to or within the area of ​​the spring assemblies for advantageous suspension comfort.

[0035] In a variation of the present disclosure, the plurality of dampers comprises a first damper arranged substantially vertically and a second damper arranged substantially horizontally. In other words, the longitudinal axis of the first damper is arranged parallel to the vertical direction and the longitudinal axis of the second damper is arranged substantially horizontally. The first damper is configured to absorb vertical vibrations during travel and the second damper is configured to absorb lateral / horizontal vibrations during travel. This variation provides an advantageous suspension comfort against vertical and lateral vibrations during travel of the bogie.

[0036] If the base frame is arranged parallel to the wheel frame, this is favorable for a compact structure which increases the available internal space in the rail vehicle. In particular, the main extension plane of the base frame is arranged parallel to the main extension plane of the wheel frame. The main extension plane is preferably arranged perpendicular to the steering axis. The main extension plane is an imaginary plane which extends along the two main extension directions of the base frame and the wheel frame. In the mounting position, the main extension planes of the base frame and the wheel frame extend according to this variant in the lateral and running directions. This compact structure advantageously allows damping of movements in certain directions and high stiffness in other directions.

[0037] A particularly compact construction is possible if the maximum vertical extension of the wheels exceeds the maximum vertical extension of the base frame, in other words the base frame is arranged vertically within the range of the vertical extension of the wheels.

[0038] In a variant of the disclosure, the base frame is arranged perpendicular to the steering axis and above an imaginary separation plane intersecting the center of the first wheel and / or the second wheel. In the case where the wheel rotation axes are arranged parallel, the imaginary separation plane extends along the wheel rotation axes. It is further preferred that the wheel frame is approximately below the imaginary plane. In other words, the base frame is arranged vertically above the wheel rotation axis, and the wheel frame is approximately arranged with a majority of its volume vertically below the wheel rotation axis. This structure allows for an advantageous compact design that increases the available interior space in the rail vehicle.

[0039] It is favorable for a compact construction if the two wheels are at least partially surrounded by a frame, in particular a base frame and / or a wheel frame, which for example extends in the direction of travel and / or transversely beyond the wheels.

[0040] It is preferred for a particularly compact construction if the base frame is arranged, approximately for the majority of its volume, within an imaginary box defined by the outer edges of the wheel frame.

[0041] In a variant of the disclosure, the frame further comprises a number of struts, preferably four struts, connecting the base frame with the wheel frame, the longitudinal axis of the struts being arranged perpendicular to the steering axis. The struts are preferably connected to the base frame and the wheel frame in such a way that vertical movement of the base frame and the wheel frame is possible between the base frame and the wheel frame, and further movements, in particular lateral movements and movements in the direction of travel, are inhibited. In other words, the struts ensure a vertical degree of freedom between the base frame and the wheel frame, and create stiffness in other directions. Thus, steering torques / movements, for example from steering actuators, can be advantageously transferred from the base frame to the wheels via the struts. To achieve the desired stiffness, the struts may be arranged parallel to each other and parallel to the direction of travel of the bogie.

[0042] In further variations, the frame and / or other components of the bogie are, are constructed from, or at least partially include lightweight materials. The lightweight materials may include aluminum, aluminum alloys, lightweight steel alloys, composite materials, fiber-reinforced composite materials, or combinations of the aforementioned materials. The lightweight construction of the bogie helps to reduce the energy consumption of the rail bogie during operation, improving its overall environmental impact.

[0043] In a preferred variant, the frame and / or other components of the bogie have a lightweight design shape. The lightweight design shape of a part is a shape that is lighter due to a specific design without losing its necessary functionality. The lightweight design shape comprises, for example, a slender / thin structure that follows its respective function, as compared to a standard design constituted by standard parts, such as bars, rods or standard shapes. Furthermore, the lightweight design shape is determined, for example, using simulation results of the respective parts of the rail bogie, so that material is added where it is needed and removed where it is not needed.

[0044] In one aspect of the disclosure, a rail vehicle is provided that includes a bogie as described above and below.

[0045] In a further aspect of the present disclosure, a method for steering a bogie of a rail vehicle is provided, the method comprising the steps of: Providing a rail vehicle comprising a bogie as described above and as follows; measuring, by at least one sensor assembly, a lateral position of a tread of at least one of the two wheels relative to a railroad track; receiving, at a control unit, the measured lateral position and calculating a steering angle using the received lateral position; Rotating the bogie about the steering axis by the calculated steering angle by a steering device to steer the bogie relative to the base. The steering device may comprise a steering actuator and / or at least one electric engine and / or at least one brake.

[0046] It should be understood that both the foregoing general description and the following detailed description present embodiments and are intended to provide an overview or framework for understanding the nature and character of the present disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments and, together with the description, serve to explain the principles and operation of the disclosed concepts. [Brief description of the drawings]

[0047] The disclosure set forth herein will become more fully understood from the following detailed description and the accompanying drawings, which should not be construed as limiting the disclosure set forth in the appended claims.

[0048] [Figure 1] FIG. 1 is a perspective view of a first modified example of a dolly according to the present disclosure. [Diagram 2] FIG. 13 is a first perspective view of a second variant of the dolly according to the present disclosure. [Diagram 3] FIG. 3 is a second perspective view of the second modified example of FIG. 2. [Figure 4] FIG. 4 is a detailed view of FIG. [Diagram 5] FIG. 3 is a top view of a second modified example of FIG. 2. [Figure 6] FIG. 6 is a first cross-sectional view of the second variant of FIG. 5 as indicated by section line I. [Figure 7] FIG. 6 is a second cross-sectional view of the second variant of FIG. 5 as indicated by section line J. [Figure 8] FIG. 11 is a first perspective view of a modified example of the wheel of the bogie. [Figure 9] FIG. 11 is a second perspective view of a modified example of the wheel of the bogie. [Figure 10] FIG. 13 is a perspective view of a modified example of the swing arm of the bogie. [Figure 11] FIG. 13 is a perspective view of a modified example of the base frame of the dolly. [Figure 12] FIG. 13 is a perspective view of a modified example of the wheel frame of the bogie. [Figure 13] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all, features are shown. Indeed, the embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are presented so that this disclosure will satisfy applicable legal requirements. Wherever possible, the same reference numbers will be used to refer to the same components or parts.

[0050] FIG. 1 shows a perspective view of a first variant of a bogie according to the present disclosure. FIG. 2 shows a first perspective view of a second variant of a bogie according to the present disclosure. FIG. 3 shows a second perspective view of the second variant of FIG. 2. FIG. 4 shows a detailed view of FIG. 3. FIG. 5 shows a top view of the second variant of FIG. 2. FIG. 6 shows a first cross-sectional view of the second variant of FIG. 5 shown by the cross-sectional line I. FIG. 7 shows a second cross-sectional view of the second variant of FIG. 5 shown by the cross-sectional line J. FIG. 8 shows a first perspective view of a variant of a wheel of the bogie. FIG. 9 shows a second perspective view of a variant of a wheel of the bogie. FIG. 10 shows a perspective view of a variant of a swing arm of the bogie. FIG. 11 shows a perspective view of a variant of a base frame of the bogie. FIG. 12 shows a perspective view of a variant of a wheel frame of the bogie. FIG. 13 shows a perspective view of a joint of the bogie.

[0051] For example, as seen in Figures 1, 2, 3 and 5, the bogie 1 comprises a base 2 configured to be attached to a chassis of a rail vehicle. The base 2 may be connected to a coupling 9 configured to be connected to the chassis of the rail vehicle during operation of the bogie 1. The bogie 1 further comprises a frame 3 rotatably arranged relative to the base 2 about a vertical steering axis 4. The bogie 1 further comprises two wheels 5 with treads 6. The treads 6 or tread profile are radially outer portions of the wheels 5. The treads 6 comprise a contact or rolling surface that contacts the rail track during operation. The two wheels 5 are rotatably arranged relative to the frame 3 about respective wheel rotation axes 7. The wheel rotation axes 7 of the two wheels 5 are arranged approximately coaxially with each other, and the steering axis 4 is arranged in the lateral direction Y between the two wheels 5. In another variant, the wheel rotation axes 7 may be arranged at a certain angle with respect to the lateral direction Y. In this case, the wheel rotation axes 7 are inclined with respect to the lateral direction Y. FIG. 1 further shows a cover 30 arranged on the frame 3 to protect the bogie 1 during operation.

[0052] The bogie 1 further comprises a sensor assembly 11, best shown in Figures 3, 4 and 7, configured to measure the lateral position of the treads 6 of the two wheels 5 relative to the railway track during operation. The sensor assembly 11 allows the position of the treads 6 of the wheels 5 on the railway track to be measured during operation, which is important for controlling the position of the treads 6 of the wheels 5 relative to the railway track for noise and wear control.

[0053] Figure 1 further shows a steering actuator 16 connected to the frame 3 and to the linkage 9. The linkage 9 is also shown in Figure 13. Movement of the steering actuator 16 rotates the frame 3 about the steering axis 4 by a steering angle relative to the base 2 and relative to the linkage 9 and also relative to the chassis of the rail vehicle.

[0054] 2, 3, 5, 7, and 8 to 10 further show a swing arm 20. Each wheel 5 is pivotally mounted to the frame 3 by means of a swing arm 20. The swing arm 20 is arranged to be pivotable to the frame 3 about a pivot shaft 21 against the force of a swing arm spring 22, best shown in Figs. 6 and 8. The pivot shaft 21 is arranged parallel to the wheel rotation axis 9. The fulcrum of the wheel 5 is arranged on the swing arm 20 between the pivot shaft 21 and the swing arm spring 22. In other words, according to the embodiment shown in the figures, the wheel 5 is mounted to the swing arm 20 between the pivot shaft 21 and the swing arm spring 22.

[0055] Figures 3, 4 and 7 show the sensor assembly 11 in more detail. The sensor assembly 11 comprises a front sensor 13 arranged in front of the respective tread 6 of the wheel 5 with respect to the direction of travel X of the bogie 1. The sensor assembly 11 further comprises a rear sensor 14 arranged behind the respective tread 6 of the wheel 5 with respect to the direction of travel X of the bogie 1. As best shown in Figure 3, both wheels 5 of the bogie 1 are equipped with a front sensor 13 and a rear sensor 14. The front sensor 13 and the rear sensor 14 are arranged on a sensor bracket 15 that is pivotally mounted on a swing arm 20. The sensor bracket 15 extends along the wheels 5 and holds each sensor 13, 14 in place during travel of the bogie 1. The sensor bracket 15 is pivotally arranged with respect to the swing arm 20 about a levelling axis 10, best shown in Figures 4 and 7. The levelling axis 10 is arranged parallel to the respective wheel rotation axis 4 and parallel to the pivot axis 21.

[0056] The bogie 1 further comprises a levelling actuator 8, best shown in Figs. 6 and 11, coupled to the frame 3 and to the respective sensor bracket 15. The linear movement of the levelling actuator 8 adjusts the vertical distance of the front sensor 13 and / or the rear sensor 14 relative to the railroad track during the movement of the bogie 1. Movements of the swing arm 20, which may change the vertical distance of at least one of the sensors 13, 14, can be compensated for by the movement of the levelling actuator 8. In the variant of the present disclosure shown in the figures, the linear movement of the levelling actuator 8 causes the coupled sensor bracket 15 to pivot about the levelling axis 10. The pivoting about the levelling axis 10 compensates for possible deflections of the swing arm 20 relative to the swing arm spring 22 during the movement of the bogie 1, allowing the vertical position of each sensor 13, 14 to be as stationary as possible. In another variant, the levelling actuators 8 associated with each sensor 13, 14 may move independently, such that each of the sensors 13, 14 is always in a predetermined vertical position.

[0057] Figures 1 to 9 further show that each wheel 5 is provided with an electric engine 18 and a brake 19. The electric engine 18 is arranged to drive the respective wheel 5 during travel, as required. The brake 19 is arranged to slow the respective wheel 5 during travel of the bogie 1, as required. The brake 19 is a disc brake, the disc of the disc brake being located on the same shaft as the respective wheel 5 and the respective electric engine 18. The wheels 5, electric engine 18 and disc are partially surrounded and held by a swing arm 20, best shown in Figures 8 and 9. A brake caliper of the brake 19 is located on the swing arm 20.

[0058] These figures further show diagrammatically a control unit 17, which is arranged, for example, in the bogie 1 or at another location of the rail vehicle. The control unit 17 is configured to receive measured lateral positions of the respective sensors 13, 14 during travel of the bogie 1 and is further configured to determine a steering angle based on the received lateral positions. The control unit 17 is further configured to control the steering actuator 16 and / or to control the electric engine 18 and the brakes 19 based on the determined steering angle in order to rotate the frame 3 about the steering axis 4 relative to the base 2.

[0059] In particular, Fig. 1, Fig. 2, Fig. 3, Fig. 6, Fig. 11 or Fig. 12 show that the frame 3 comprises a base frame 23 and a wheel frame 24. Fig. 11 shows the base frame 23 in detail and Fig. 12 shows the wheel frame 24 in detail. The base frame 23 is arranged generally above the wheel frame 24. The base frame 23 is interconnected to the wheel frame 24 via the spring damping device 12 and vice versa. The base 2 of the bogie 1 is arranged on the base frame 23. The two wheels 5 are arranged on the wheel frame 24 via the swing arm 20. The spring damping device 12 comprises a number of dampers 25 configured to damp different types of movements / vibrations of the bogie 1 during travel. According to the variant of the present disclosure shown in the figures, four of the dampers 25 are arranged vertically. In other words, the longitudinal axes of the four dampers 25 are arranged parallel to the vertical direction Z and these dampers 25 are configured to damp vertical vibrations. Further, two of the dampers 25 are disposed generally in the lateral direction Y, best shown in FIG. 5. These dampers 25 are configured to damp vibrations / movements in the lateral direction. The spring damping device 12 further comprises four spring assemblies 26. The spring assemblies 26 comprise a first spring 27 and a second spring 28. The first spring 27 is disposed coaxially with respect to the second spring 28. The second spring 28 has a smaller radial extent than the first spring 27 and is disposed within the first spring 27. Both springs 27, 28 engage the base frame 23 and the wheel frame 24 and are configured to absorb vibrations resulting from the movement of the bogie 1 on the railroad track in combination with the dampers 25 during operation of the bogie 1.

[0060] The swing arm 20 is mounted to the wheel frame 24 so as to be pivotable against the force of the swing arm spring 22. Figure 12 shows the mounting point of the pivot shaft 21 of each swing arm 20 on the wheel frame 24. Figures 10 and 12 further show a spring seat 32 on the swing arm 20 and a spring seat 33 on the wheel frame 24 for the swing arm spring 22. The swing arm spring 22 engages with the swing arm 20 and the wheel frame 24 via the spring seats 32, 33.

[0061] The figure further shows stops 31, best seen in Figures 2 and 12, located on the base frame 23. Some of the stops 31 limit the movement of the base frame 23 relative to the wheel frame 24. Other stops 31 limit the maximum possible rotation of the frame 3 relative to the base 2.

[0062] 1 to 5, and in particular 6 and 7, show the compact construction of the bogie 1. This is the result of a compact combined design of the respective parts of the bogie 1. The wheels 5 are combined with the electric engine 18 and the brakes 19 and are partly surrounded and held by the swing arms 20. The wheel frames 24 partly surround the swing arms 20, and a major part of the wheel frames 24 is arranged below the wheel rotation axis 7. A major part of the base frame 23 is arranged above the wheel rotation axis 7 and does not extend beyond the maximum radial extension of the wheels 5 relative to the vertical direction Z. The maximum vertical extension of the wheel frames 24 also does not extend beyond the maximum radial extension of the wheels 5 relative to the vertical direction Z by more than 10 millimeters, preferably 5 millimeters. This increases the available interior space in a railway vehicle using the bogie 1 (see figs. 6 and 7).

[0063] 1, 2, 5 and 6 further show four struts 29 connecting the base frame 23 with the wheel frame 24. The longitudinal axes of the struts 29 are arranged parallel to one another and, in the rest state of the bogie 1, parallel to the running direction X. The struts 29 are connected to the base frame 23 and to the wheel frame 24 in such a way that a vertical movement of the base frame 23 and the wheel frame 24 between these two parts is allowed within a certain range (damped by the spring-damping assembly 12) and a movement in the running direction X is prevented. The operation of the steering actuator 16 thus results in the desired direct and precise steering of the wheels 5, which is advantageous in particular in tight curves.

[0064] Rather, the words used in this specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. [Explanation of symbols]

[0065] 1 Cart 2. Bass 3 Frame 4 Steering shaft 5 wheels 6 Tread 7 Wheel rotation axis 8 Leveling Actuator 9 Connecting part 10 Leveling Axis 11 Sensor Assembly 12 Spring damping device 13 Front Sensor 14 Rear Sensor 15 Sensor bracket 16 Steering actuator 17 Control Unit 18 Electric Engine 19 Brakes 20 Swingarm 21 Pivot axis 22 Swing arm spring 23 Base Frame 24 Wheel Frame 25 Damper 26 Spring Assembly 27 First Spring 28 Second Spring 29 Strut 30 Cover 31 Stopper 32 Swingarm spring seat 33 Wheel frame spring seat X Traveling direction Y Horizontal Z vertical direction

Claims

1. A bogie (1) for a railway vehicle guided on a railway track, a. a base (2) configured to be attached to the chassis of the rail vehicle; b. A frame (3) rotatably disposed relative to the base (2) about a vertical steering axis (4); c) two wheels (5) each having a tread (6) rotatably arranged relative to the frame (3) about a respective wheel rotation axis (7), the two wheels (5) being spaced apart from each other in a lateral direction (Y); d. the steering shaft (4) is disposed in the lateral direction (Y) between the two wheels (5); e. at least one sensor assembly (11) configured to measure, during travel, the lateral position of the tread (6) of at least one of the two wheels (5) relative to the railway track.

2. 2. The bogie (1) according to claim 1, wherein each of the wheel rotation axes (7) is arranged parallel to one another and perpendicular to the steering axis (4).

3. 3. The trolley (1) according to claim 1 or 2, wherein the at least one sensor assembly (11) comprises a front sensor (13) arranged in front of the respective wheel (5) and / or a rear sensor (14) arranged behind the respective wheel (5) relative to the direction of travel (X) of the trolley (1).

4. A trolley (1) as claimed in any one of claims 1 to 3, wherein each wheel (5) is attached to the frame (3) by a swing arm (20), the swing arm (20) being rotatable relative to the frame (3) about a pivot axis (21) against the force of a swing arm spring (22).

5. The bogie (1) of claim 4, wherein the pivot shaft (21) is arranged forward of each of the wheel rotation shafts (7) with respect to the running direction of the bogie (1), and the swing arm spring (22) is arranged rearward of each of the wheel rotation shafts (7) with respect to the running direction of the bogie (1).

6. The bogie (1) according to any one of the preceding claims, wherein the sensor assembly (11) is at least partially arranged on the frame (3) or on the swing arm (20).

7. The bogie (1) according to claim 6, wherein the front sensor (13) and / or the rear sensor (14) of the sensor assembly (11) are interconnected to the frame (3) or the swing arm (20) by a sensor bracket (15).

8. 8. The bogie (1) according to claim 6 or 7, wherein the front sensor (13) and / or the rear sensor (14) of the sensor assembly (11) are arranged displaceable in the vertical direction (Z) during operation in order to adjust the vertical distance to the railway track.

9. 9. The bogie (1) according to claim 8, wherein each of the sensor assemblies (11) comprises at least one levelling actuator (8) configured to adjust the vertical distance of the front sensor (13) and / or the rear sensor (14) of the respective sensor assembly (11) relative to the railway track during travel.

10. The bogie (1) according to any one of claims 1 to 9, further comprising a steering actuator (16) connected to the frame (3) and configured to rotate the frame (3) during travel about the steering axis (4) by a steering angle relative to the base (2).

11. Each wheel (5) a. an electric engine (18) configured to drive each of said wheels (5) during travel; and / or b. a brake (19) configured to slow down said respective wheel (5) during travel; The bogie (1) according to any one of the preceding claims, comprising:

12. a. a controller (17) configured to receive the measured lateral position during operation and to determine a steering angle based on the received lateral position; b. the control unit (17) is configured to control the steering actuator (16) based on the determined steering angle; and / or c) the control unit (17) is configured to control the at least one electric engine (18) and / or the at least one brake (19) based on the determined steering angle to rotate the frame (3) about the steering axis (4) relative to the base (2); A bogie (1) according to claim 10 or 11.

13. The bogie (1) according to any one of claims 1 to 12, wherein the frame (3) comprises a base frame (23) and a wheel frame (24) interconnected to each other via a spring damping device (12), the base (2) being arranged on the base frame (23) and the wheels (5) being arranged on the wheel frame (24).

14. 14. The bogie (1) according to claim 13, wherein the spring damping device (12) comprises a plurality of dampers (25) and a plurality of spring assemblies (26), each of the plurality of spring assemblies (26) comprising a first spring (27) and a second spring (28) arranged coaxially with each other.

15. 15. The bogie (1) according to claim 13 or 14, wherein the maximum vertical extension of the wheels (5) exceeds the maximum vertical extension of the base frame (23).

16. The bogie (1) according to any one of claims 13 to 15, wherein the frame (3) comprises a plurality of struts (29) connecting the base frame (23) with the wheel frame (24), the longitudinal axes of the struts (29) being arranged perpendicular to the steering axis (4).

17. The bogie (1) according to any one of the preceding claims, wherein the frame (3) and / or other components of the bogie (1) are in or made of lightweight materials.

18. The bogie (1) according to any one of the preceding claims, wherein the frame (3) and / or other components of the bogie (1) have a lightweight design.

19. A railway vehicle comprising a bogie (1) according to any one of the preceding claims.

20. A method for steering a bogie (1) of a railway vehicle, the method comprising the steps of: a. Providing a rail vehicle comprising the bogie (1) according to any one of claims 1 to 16; b. measuring the lateral position of the tread (6) of at least one wheel (5) of the two wheels (5) relative to the railway track by means of the at least one sensor assembly (11); c. receiving the measured lateral position in a control unit (17) and calculating a steering angle using the received lateral position; and d) rotating said bogie (1) about said steering axis (4) by said calculated steering angle by a steering device to steer said bogie (1) relative to said base (2).

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