Patent Application
20220024320
The various aspects and examples thereof relate to the field of providing brakes for magnetically suspendable vehicles and Eddy current brakes in particular.
Eddy currents are known for their braking effect without physical contact between two units between which the braking force is generated. Examples are rollercoasters and high-speed trains. In the latter, like the 700 Series Shinkansen, circular Eddy currents brakes are provided comprising a disk around an axle of a bogie and a stationary magnet. In the German ICE 3, linear Eddy current brakes are provided.
Using Eddy current brakes and linear Eddy current brakes in particular result in forces on the vehicle perpendicular to the direction of movement of the vehicle. In Rollercoasters and high-speed trains like the German ICE 3, magnets provide a magnetic field oriented vertically, which magnets may be moves towards rails in the track. In the ICE 3, the train carries magnets that interact with the rails on which the train rides. Besides a braking force, parallel to the direction of movement, this also results in forces parallel to the magnetic field orientation. These forces result in repulsion and, if the conductor is ferromagnetic, also in attraction between the conductor of the brake and magnet of the brake.
Rollercoasters and high speed trains like the German ICE 3 move using wheels that are in physical contact with rails below the vehicles. In this way, the train is constrained between two rails. Hence, use of linear Eddy current brakes with horizontally oriented field, has no major effect on stability of the vehicle during braking. If a vertically oriented field is used, any additional forces are compensated by the weight of the train.
However, if a vehicle is magnetically (contactless) suspended, magnetic forces generated by operation an Eddy current brake by means of a vertically oriented field may have consequences for the stability of the vehicle due to lack of the restraint of rails. In particular on stability in the vertical direction may be an issue and such stability may in worst case result in loss of suspension at all.
Therefore, a first aspect provides a brake module for a magnetically suspended vehicle. The brake module comprising a first magnetically active brake element coupled to a first brake magnet actuator comprised by the brake module. The first brake magnet actuator is arranged to control the first magnetically active element to provide a first magnetic brake field of a pre-determined magnitude at a first pre-determined location relative to the brake module, of which first magnetic brake field the first field lines are, in use, substantially horizontal and substantially perpendicular to a direction of travel of the vehicle.
By providing an Eddy current brake having magnetic field components that are substantially horizontally oriented, influence of magnetic forces excited by the Eddy currents generated on the (vertical) suspension are reduced and preferably minimised.
An implementation provides a brake module further comprising a second magnetically active brake element coupled to a second brake magnet actuator, the second brake magnet actuator being arranged to control the second magnetically active element to provide a second magnetic brake field of a pre-determined magnitude at a second pre-determined location relative to the brake module, of which second magnetic brake field the second field lines are, in use, substantially parallel to the field lines of the first magnetic brake field and have an orientation opposite therefrom, wherein a first pole from which the first field lines debouch is facing away from the second magnetically active element and a second pole from which the second field lines debouch is facing away from the first magnetically active element.
In this implementation, lateral forces due to magnetic field induced by Eddy currents on either side of a bogie of the vehicle may eliminate one another if they have the same magnitude. A bogie, in this respect, is an arrangement for providing suspension of a vehicle relative to a track. As such, the bogie may comprise hinges, springs, other elements or a combination thereof for providing safe and/or comfortable suspension.
Another implementation of the brake module comprises a magnetically active guide element arranged to provide a magnetic guide field of which magnetic guide field lines, in use, are substantially horizontal and substantially perpendicular to a direction of travel of the vehicle. This implementation further comprises a guide magnet actuator arranged to control the magnetically active guide element to provide a magnetic guide field of a pre-determined magnitude at a first pre-determined location relative to the brake module; and a controller. The controller is arranged to obtain a total required force to obtain or maintain a particular position of the vehicle relative to a transportation infrastructure, based on a required braking force to be provided by actuation of the magnetically active brake elements, determine a magnitude of the magnetic brake field and a resulting lateral brake force lateral to the brake module and control the guide actuator enabling the magnetically active guide element to provide a magnetic guide field at the pre-determined location resulting in a magnetic guide force such that the sum of the lateral brake force and the magnetic guide force is substantially equal to the total required force.
In particular in a bend and/or when a brake rail is provided at only one side of the vehicle, lateral forces due to braking, for example induced by Eddy currents, do not eliminate one another. In such case, additional control is required, which is provided in this implementation.
A second aspect provides a vehicle arranged to be magnetically suspendable relative to at least one guide rail comprised by a transportation infrastructure, the vehicle comprising a brake module according to the first aspect.
A third aspect provides a transportation infrastructure arranged for transportation of a vehicle according to the second aspect, the transportation infrastructure providing a track arranged to provide guidance to the vehicle, the infrastructure comprising a braking rail provided along the track, the braking rail being arranged to engage with the brake module comprised by the vehicle and provided along the track such that it is provided at the pre-determined first location relative to the brake module.
In an implementation of the third aspect, wherein the braking rail comprises a layered structure. In this implementation, currents excited in the rail may be controlled and reduced or suppressed in particular.
In another implementation, at least two layers comprise materials having different magnetic and/or electrical and/or conductive properties.
Different materials provide different Eddy current brake characteristics at different velocities of the vehicle. Providing brake rail with different materials in different layers provides efficient braking at a wide velocity range. Furthermore, incorporating a layer comprising a ferromagnetic material may provide use of the braking rail for other purposes, including, but not limited to guiding, propulsion and suspension.
It is noted that whereas the implementations discussed below relate to vehicles that are suspended from above, implementations of this various aspects on concepts with floating vehicles magnetically suspended from below are not excluded.
The various aspects and implementations thereof will now be discussed in further detail in conjunction with drawings. In the drawings,
In the tube 110, a carriage 160 is provided as a vehicle. The carriage 160 may be arranged for carrying people, goods, both, other or a combination thereof. The carriage 160 is connected to a bogie 140 as a basis for suspending the carriage 160. Between the bogie 140 and the carriage, suspension points may be provided, comprising a first air spring 172 and a second air spring 174. Additional air springs may be provided; alternatively or additionally, other types of springs or dampeners may be used. The bogie 140 is preferably elongate—as well as the carriage 160—and at corners and in between front and rear ends of the bogie 140 and the carriage 160, additional air springs may be provided.
The bogie 140 is provided with several magnetically active elements to enable safe, comfortable and efficient control over movement of the carriage 160. At the top of the bogie 140, a first magnetically active suspension element 142 and a second magnetically active suspension element 144 are provided.
The magnetically active suspension elements engage with the suspension rails; the first magnetically active suspension element 142 engages with the first suspension rail 112 and the second magnetically active suspension element 144 engages with the second suspension rail 114. In this sense, engaging means that the magnetically active suspension elements provide a magnetic field that provides a magnetic force that attracts the bogie 140 with the carriage 160 to the suspension rails and provides suspension.
At the sides of the bogie 140, a first magnetically active guide element 152 and a second magnetically active guide element 154 are provided. The magnetically active guide elements engage with the guide rails; the first magnetically active guide element 152 engages with the first guide rail 122 and the second magnetically active guide element 154 engages with the second guide rail 154. In this sense, engaging means that the magnetically active guide elements provide a magnetic field that provides a magnetic force that attracts or dispels the bogie 140 with the carriage 160 to or from the guide rails and provides guidance to the bogie 140 with the carriage 160. More in particular, operation of the magnetically active guide elements allows for controlling the lateral position of the carriage 160 in the tube 110, in a substantially horizontal direction perpendicular to a direction of movement of the carriage 160. Multiple magnetically active guide elements may be provided in line on the bogie 140, at each side of the bogie 140.
At the sides of the bogie 140, a first magnetically active brake element 162 and a second magnetically active brake element 164 are provided. The magnetically active brake elements engage with the brake rails; the first magnetically active brake element 162 engages with the first brake rail 132 and the second magnetically active brake element 164 engages with the second brake rail 134. In this sense, engaging means that the magnetically active brake elements provide a magnetic field that is intended to create Eddy currents in the brake rails. The magnetically active brake elements and the brake rails thus constitute Eddy current brakes. Multiple magnetically active brake elements may be provided in line on the bogie 140, at each side of the bogie 140.
The currents thus generated, provide magnetic fields as indicated in
As shown by
When the magnetically active brake elements are operated, a magnetic force is excited, interacting between the magnetically active brake elements and thus the carriage on one hand and the brake rails on the other hand.
With the field lines of the field provided by the magnetically active brake elements, any force due to the interaction between the magnetically active brake elements and the brake rails is in this embodiment perpendicular to the suspension force. Hence by virtue of their orthogonal orientation, braking is independent from suspension, which enhances safety.
The permanent magnet 410 may be translated perpendicularly to the direction of movement; in another embodiment, the permanent magnet 410 is moved towards the first brake rail 132 in another direction, yet having a component perpendicular to the direction of movement of the vehicle 160. In yet another embodiment, the permanent magnet 410 is brought towards the first brake rail 132 via another movement. In this way, the magnetic field strength at the location of the first brake rail 132 is controlled, thus controlling the brake force.
The magnetic force provided at a pre-determined distance to the brake rails may depend on various parameters. Hence, control of the movement of the permanent magnet 410 or of the current provided to the electromagnet 450 may be executed based on different control parameters. In one embodiment, a control parameter is the braking force applied. Other control parameters may be acceleration, jerk—or limitation thereof —, vehicle speed, position relative to an obstacle, vehicle geometry like position relative to a bend, other, or a combination thereof. To this end, the bogie 140 may comprise several sensors, including, but not limited to, speed sensors, gyroscopes, accelerometers, other, or a combination thereof, providing input to the bogie controller 146.
Upon operation of the Eddy current brake, the magnetically active brake elements are pushed away from the brake rails. At linear stretches, with brake rails provided at both sides of the tube 110, forces compensate one another at opposite lateral sides of the bogie 140. However, at switches of a track, brake rails may not be present at both sides of the tube 110. This is depicted in
In order to properly follow the curved trajectory, second magnetically active guide element 154 is actuated. In this example, two second magnetically active guide elements are provided, at a leading side of the carriage 160—or actually, the bogie 140—and at a trailing side of the carriage 160 or the bogie 140. Two second magnetically active guide elements are activated such that the centrifugal force is countered, which results in the carriage 160 following the depicted curved trajectory.
As in the middle of the switch, the first brake rail 122 is not present, at least one of the first lateral force 532 and second lateral force 532′ are not compensated by actuation of magnetically active brake elements at the left side of the vehicle. Hence, in the switch 500, during operation of the horizontal Eddy current brake, the repelling force due to operation of the Eddy current brake needs to be compensated by further actuation of the second magnetically active guide elements.
The bogie control unit 146 (
Furthermore, the bogie control unit 146 is arranged to control the magnetically active guide elements to compensate for a force acting on the bogie 140 by virtue of operating the magnetically active brake elements in a braking action. Actuating the magnetically active brake elements results in a braking force acting opposite to the direction of movement of the bogie 140 and the carriage 160, but also in a force pushing the magnetically active brake elements away from an adjacent brake rail. Such force may be countered by operating the magnetically active guide elements, for example to maintain distance between the bogie 140 and the guiding tracks or the wall of the tube 110 within a pre-determined range. Furthermore, the magnetically active brake elements may be used to push the bogie 140 with the carriage 160 away from the brake rail.
In the examples above, the transport infrastructure has been presented as comprising three types of rails, for suspension, guiding and braking. This constellation allows for optimising materials and further constructions of the rails for each purpose. The suspension rails are preferably manufactured from a ferromagnetic material to provide a significant magnetic force between the magnetically active suspension elements and the suspensions rails.
It is preferred that a low amount of Eddy currents is generated in the suspension rails that may reduce the effective forces and may lead to drag and loss of energy. This is in particular the case if the suspension rails are also use for propulsion of the vehicle with the bogie 140 and the carriage 160. Ensuring low Eddy currents may be effectuated by providing the suspension rails in a layered structure, in which the layers are provided parallel to the orientation of the suspension field excited by the magnetically active suspension elements. Between the layers, an electrically insulation layer may be provided.
The brake rails are preferably provided such that an exciting magnetic field creates significant Eddy currents, but relatively low magnetic interaction as a result of the Eddy currents. Hence, a layered structure is not preferred—or in any case not a layered structure in which layers are parallel to the orientation of the braking field. However, layers may be oriented perpendicularly relative to the braking field excited by the magnetically active brake elements. Hence, the brake currents are preferably provided in a non-ferromagnetic material like copper or aluminium. In one embodiment, material comprised by the brake rails at a specific location may be chosen dependent on an expected speed at the specific location. High-conductivity material is preferred at higher speeds and low-conductivity material is preferred at lower speeds.
As for the guide rails, a ferromagnetic material is preferred. Furthermore, as Eddy currents are preferably kept low, a layered structure is preferred, with layers provided parallel to the orientation of the guiding field. Since the guiding field is substantially perpendicularly oriented relative to the suspension field, it is rather difficult to use one and the same rails for guiding and suspension—though this is not excluded as an option; efficiency may be obtained by providing layers under an angle with mutually orthogonally oriented field. Such angle is preferably 45°, but may be between 30° and 60° with either field orientation.
The first suspension rail 112 further comprises a second layer 612 of a diamagnetic material like copper, lead, other, or a combination thereof. The first suspension rail 112 further comprises a third layer 614 of a ferromagnetic material like steel, iron, cobalt, nickel, other, or a combination thereof. It is noted that for all layers, particular alloys may be used. A fourth layer 616 comprises again one or more paramagnetic materials and a fifth layer 618 comprises again one or more diamagnetic materials. It is noted that various options may be envisaged in combining layers of ferromagnetic material and layers comprising other materials in any number of layers of any thickness.
Also indicated in
Various further options may be envisaged, in which a part of the first suspension rail 112 close to the electromagnet 450 comprises more layers of diamagnetic and/or paramagnetic material. Further away, from the electromagnet 450, the first suspension rail may comprise more layers of ferromagnetic material. In this embodiment, the further electromagnet or the first magnetically active suspension element 142 more in general, is provided below the left side of the first suspension rail 120 as depicted in
Use of different and multiple paramagnetic and/or diamagnetic materials in various layers is a preferred embodiment, as the braking effect by using different materials varies depending on the velocity of the carriage. Hence, providing multiple layers of different paramagnetic and/or diamagnetic materials in shared brake and suspension rails or in dedicated brake rails provide optimal braking over a wide range of the velocity of the carriage 160.
In another embodiment, the braking rail 112 as depicted by
In another embodiment, one rail at each side of the tube 110 is shared for guiding and braking. In such embodiment, braking may be executed by providing magnetically active brake elements under an angle relative to magnetically active guide elements, in combination with a rail as depicted by
In yet another embodiment, the various materials of the first brake rail 132 or the first suspension rail 112—and the second brake rail 134 and the second suspension rail 114—are stacked in the direction of movement.
At a side of the elongate body opposite to the side from which the first metal strips 712 extend, second metal strips 714 extend in a direction perpendicular to the length of the elongate support member 702 and in a direction opposite to the direction to which the first metal strips extend.
The elongate body 702, the first metal strips 712 and the second metal strips 714 are preferably provided in one and the same material, such that the first brake rail 132 may be manufactured from one piece of material by sawing, milling, grinding, other or a combination thereof to form the air gaps between the first metal strips. In another embodiment, the first strips 712, the second strips 714 and the elongate support member 702 may comprise different materials.
In one embodiment, two, three, four or more different materials are used for the first strips 712 and the second strips 714. In this embodiment, every second, third, fourth or nth strip is made from the same material or from the same compound like an alloy. The various different metals may be chosen from the same set of metals as discussed in conjunction with
In another embodiment, that may be combined with any other embodiment of the first brake rail 132, the width of the air gaps is substantially equal to the width of the first metal strips 712 and the second metal strips 714, measured along the length of the elongate support member 702. In yet another embodiment, the width of the air gap is smaller or larger than the width of the first metal strips 712 and the second metal strips 714, measured along the length of the elongate support member 702.
In again another embodiment, the width of the air gaps and/or the width of the first metal strips 712 and the second metal strips 714, measured along the length of the elongate support member 702 may be varied along the length of the elongate support member 702. The variation may be periodically, incrementing, decrementing, random, or any combination thereof.
In
In the embodiments discussed above, embodiments with one to two sets of strips and one to two sets of air gaps are discussed. It is noted that also embodiments may be envisaged with multiple layers of air gaps provided parallel to one or more elongate support bodies provided substantially parallel to the length of the first brake rail 132. In one particular embodiment, four to ten elongate support bodies are provided parallel to one another and connected by means of studs as metal strips. The resulting first brake rail 132 may have air gaps oriented parallel to the elongate support bodies rather than perpendicular to the elongate support bodies, stacked in a direction perpendicular to the elongate support bodies.
In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being “on” or “onto” another element, the element is either directly on the other element, or intervening elements may also be present. Also, it will be understood that the values given in the description above, are given by way of example and that other values may be possible and/or may be strived for.
Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in the Figures, wherein functions carried out by one component in the embodiment provided are distributed over multiple components.
It is to be noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting examples. For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.
The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality.
A person skilled in the art will readily appreciate that various parameters and values thereof disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.
It is stipulated that the reference signs in the claims do not limit the scope of the claims, but are merely inserted to enhance the legibility of the claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NL2019/050825 | 12/11/2019 | WO | 00 |
