Patent Publication Number: US-2011061561-A1

Title: Magnetic levitation vehicle with a plurality of driving-and braking magnets

Description:
The invention relates to a magnetic levitation vehicle of the type described in the preamble of claim  1 . 
     Known magnetic levitation vehicles of this type (DE 10 2004 013 994 A1) have braking magnets that function as electromagnetic eddy current brakes. They are installed at preselected positions of the magnetic levitation vehicle and interact with electrically and magnetically conductive reaction rails mounted on the guideway. The magnetic levitation vehicles are also equipped with driving magnets which interact with the same reaction rails and lateral guidance rails (DE 10 2004 056 438 A1). The driving magnets are accommodated in a plurality of magnet units disposed one behind the other in the longitudinal direction of the vehicle or the direction of travel; the magnet units can accommodate four driving magnet coils in each of two planes i.e. a total of eight driving magnet coils. This configuration is used, in particular, to electrically interconnect the driving magnet coils in pairs and thereby ensure extensive redundancy when the magnetic levitation vehicle is operated. In one practical application, two groups of three such magnet units are provided per section and on each side of the vehicle, the two groups being separated by a braking magnet disposed between them. It is also possible for driving magnet units to be disposed in the transition regions between two sections. The braking magnets can be disposed within or between two levitation chassis of the vehicle to transfer the braking forces via these levitation chassises to a coach body of the magnetic levitation vehicle. 
     A disadvantage of the above-described design is that the chain of driving magnets, which otherwise extends along the entire length of the vehicle, is interrupted by each braking magnet. The two resultant load alternations generate undesired moments and forces, in particular when magnetic levitation vehicles travel rapidly, that must be absorbed in addition to the inevitable load alternations of the guideway and/or vehicle that occur at the ends of the vehicle. In addition, the zones that are unoccupied by driving magnets and are required for the braking magnets make additional measures necessary, mainly for reasons of redundancy, e.g. a different design of the driving magnet units that are adjacent to the braking magnets, and/or the installation of mechanical guiding aids (runners) that become effective if the driving magnets disposed in these regions fail. 
     Proceeding therefrom, the invention is based on the technical problem of designing the magnetic levitation vehicle of the type initially described such that the aforementioned additional measures can be largely avoided. 
     This problem is solved, according to the invention, by the characterizing features of claim  1 . 
     The invention has three advantages in particular. Since the braking magnetic poles are accommodated exclusively in one plane of the magnet units, and the driving magnet coils (with the preferable exception of the vehicle ends) are accommodated exclusively in the other plane of the magnet units, the chain of driving magnets between the vehicle ends can be designed without a gap i.e. continuous along the entire length of the vehicle. As a result, the load alternations that otherwise occur at the installation sites of the braking magnets are eliminated. In addition, similarly designed magnet units can be installed continuously, except in the end regions, thereby reducing manufacturing costs. Finally, the braking forces can be distributed along the vehicle more evenly than was previously possible since the position of the braking magnets is no longer limited to the central region of the vehicle, which simultaneously has an advantageous effect on the desired redundancy of the braking forces. 
     Further advantageous features of the present invention result from the dependent claims. 
    
    
     
       The invention is explained below in greater detail with reference to the attached drawings of embodiments. They show: 
         FIG. 1 : a schematic side view of a part of an end section of a known magnetic levitation vehicle comprising driving- and braking magnets; 
         FIG. 2 : a side view, which corresponds to that shown in  FIG. 1 , of a part of an end section of a magnetic levitation vehicle according to the invention; 
         FIG. 3 : an extreme simplification of a side view of a middle section of a magnetic levitation vehicle according to the invention; 
         FIG. 4 : an enlarged cross section through a first embodiment of a magnet unit according to the invention, in a section that includes a driving magnet and a braking magnet; 
         FIG. 5 : the front view of a part of the magnet arrangement depicted in  FIG. 4 , with one lateral guide rail omitted; and 
         FIGS. 6 and 7 : views based on  FIGS. 4 and 5  of a second embodiment of the magnet unit according to the invention. 
     
    
    
       FIG. 1  shows a part of a known magnetic levitation vehicle  1  which is an end section that includes nose-side end  2 . A longitudinal direction of magnetic levitation vehicle  1 , which is also its direction of travel, is indicated by an arrow v. 
     Furthermore, a few levitation chassises  3  through  5  are shown in basic schematic depictions; levitation chassis  3  through  5  are disposed one behind the other in the longitudinal direction of vehicle  1 , and they are coupled via not-shown air-springs to a carriage housing  6  of magnetic levitation vehicle  1 . Levitation chassis  3  disposed furthest to the front includes support elements, which are interspaced in the longitudinal direction and are connected by longitudinal supports, in the form of levitation chassis frames  8  and  9 , each of which is provided with a front and a rear support part  10 ,  11  and  12 ,  14 , respectively. Subsequent levitation chassises  4  and  5  are similary designed. In the embodiment, a magnet unit  15  that is furthest to the front in direction of travel v is connected to levitation chassis  3  in a manner such that its front end is securely connected to rear support part  11  of front levitation chassis frame  8 , and its rear end is securely connected to front support part  12  of rear levitation chassis frame  9 . A magnet unit  16  that is next in line is hingedly connected at its front end to rear support part  14  of rear levitation chassis frame  9  and, at its rear end, to a front support part  17  of a front levitation chassis frame  18  of levitation chassis  4  disposed thereafter, in the direction of travel. A third magnet unit  19  is securely connected to levitation chassis  4  similarly to first magnet unit  15 . All three magnet units  15 ,  16  and  19  are provided with driving magnet coils  20 ,  21  and  22 , which are shown shaded, depending on the particular requirements. For this purpose, each magnet unit includes four installation sites  23 , for the driving magnet coils  20  and  22  and their cores and windings, in each of two planes which are disposed one above the other, installation sites  23  being disposed closely behind and above each other. According to  FIG. 1 , e.g. two of these installation sites  23  are unoccupied in magnet units  15  and  19 , while the four installation sites disposed in the lower plane are unoccupied in magnet unit  16 . 
     The above-described configuration ends at a brake magnet  24 , the length of which advantageously corresponds to the length of a magnet unit  15 ,  16 ,  19 . In direction of travel v, brake magnet  24  is followed by corresponding magnet units, starting with a magnet unit  25 , which have a mirror-image arrangement of the driving magnet coils which extend to the other end of the vehicle. The result is a chain of magnet units  15 ,  16 ,  19 ,  25 , etc., and, installed therein, driving magnet coils  20 ,  21 ,  22 , etc., the chain being interrupted in the region of braking magnet  24 , thereby resulting in a zone at that point that contains no driving magnets and results in the initially mentioned load alternation that occurs during operation of magnetic levitation vehicle  1 . 
       FIG. 1  also shows that magnet unit  15  disposed on nose-side end  2  of magnetic levitation vehicle  1 , and magnet units  19  adjacent to braking magnet  24  each include a total of six driving magnet coils  20  and  22 , respectively, which are distributed between two planes, while magnet unit  16  is provided with a total of four driving magnet coils  21  in only one plane, which is the upper plane in this case. The configuration on the side of magnetic levitation vehicle  1  disposed to the right of braking magnet  24  in  FIG. 1 , which is not shown in entirety, is similarly affected; only magnet unit  25  adjacent to braking magnet  24  is indicated. As a result, regions that are particularly exposed and abut magnet-free zones are bounded by a larger number of driving magnet coils that are less exposed regions. 
     Brake magnet  24 , which is disposed in a central region of magnetic levitation train  1 , is preferably designed as an eddy current brake. It is used, in particular, to ensure that magnetic levitation vehicle  1  can be braked and stopped safely if the elongated-stator linear motor fails; magnetic levitation vehicle  1  of the above-described type is typically equipped with an elongated-stator linear motor which may also be used for braking. 
     Details of the above-described configuration and its advantages are provided in DE 10 2004 056 438 A1 and DE 10 2004 013 994 A1, in particular, which are hereby made the subject matter of the present disclosure via reference, to avoid repetition. 
       FIG. 2  shows a schematic representation of an embodiment of a driving- and braking system according to the invention. In contrast to  FIG. 1 , middle braking magnet  24  is omitted in this case. Instead, a further magnet unit  26  is provided, which is hingedly connected to levitation chassises  4  and  5 , as shown in  FIG. 1 ; similar to magnet units  15 ,  16 ,  19  and  25 , magnet unit  26  includes four installation sites  23  for driving magnet coils  27  in each of two planes. Of these eight installation sites  23  in all, only the four installation sites  23  disposed in the upper plane are occupied by driving magnet coils  27 , while the remaining installation sites  23  do not contain driving magnet coils  27 . Furthermore, according to the invention, magnet units  19  and  15  adjacent to magnet unit  26  are provided with driving magnet coils  22  and  28  only in one plane, which is the upper plane in this case, and therefore lower installation sites  23  are unoccupied by driving magnet coils in magnet units  19  and  25  as well. 
     As a result, only magnet units  16 ,  19 ,  26 ,  25 , etc., are disposed between the two magnet units  15  which are located at the ends of the vehicle; in a single plane, which is the upper plane in this case, magnet units  16 ,  19 ,  26 ,  25 , etc. are occupied by driving magnet coils  21 ,  22 ,  27 ,  28  in all four installation sites  23 . If magnet units  15  are fully occupied by driving magnet coils  20  on the front and the rear vehicle ends simultaneously, at least in the same upper plane, then—as is particularly preferred—all of these driving magnet coils  20 ,  21 ,  22 ,  27 ,  28 , etc. form a chain of driving magnets that extends continuously from front to back, without any gaps, except for the relatively narrow gap between the magnet units, which is substantially inconsequential in this case, thereby forming a continuous band of magnetic flux. 
     Although driving magnet coils  20 ,  21 ,  22 ,  27 ,  28 , etc., should be disposed basically exclusively in one and the same plane, which is the upper plane in this case, of magnet units  15 ,  16 ,  19 ,  26 ,  25 , etc., it can be advantageous for reasons of redundancy or other reasons to provide the first and the last magnet unit  15  with e.g. two driving magnet coils  20  also in the second plane of installation, which is the lower plane in this case. In contrast, all other magnet units are equipped with driving magnet coils exclusively in the upper plane. 
     Since driving magnet coils  20  through  22 ,  27 ,  28 , etc. are disposed only in the first, upper plane, the second, lower plane of installation sites  23  of magnet units  15 ,  16 ,  19 ,  26 ,  25 , etc. is unoccupied. Unoccupied installation sites  23  are used, according to the invention, for the installation of brake magnets  30 , as depicted in  FIG. 2  for magnet units  16  and  26 . As a result, the advantage is achieved that braking magnets  30  can likewise be distributed practically along the entire length of the vehicle, thereby ensuring that the braking forces are distributed approximately uniformly along the entire length of the vehicle, which greatly reduces the loads that are exerted locally on the lateral guide rails. Since magnet units  15 ,  16 ,  19 ,  25 , etc. and their installation sites  23  are already present anyway in known magnetic levitation vehicles, as shown in  FIG. 1 , but can remain partially unoccupied in that case, the amount of additional design-related effort required to install braking magnets  30  in unoccupied installation sites  23  is minimal. In addition, the invention increases functional redundancy since, instead of a single, central braking magnet  24  ( FIG. 1 ), a plurality of small braking magnets  30  ( FIG. 2 ) is now provided. The additional cabling that is required due to the plurality of braking magnets  30  is acceptable, especially since it is at least partially compensated for by the reduced requirement for cabling for driving magnet coils  22  in the region of central braking magnets  24  and the elimination of cabling for the central braking magnet  24  ( FIG. 1 ). 
     For the rest, braking magnets  30  can be composed, in a known manner, of electromagnets composed of north and south poles in alternation (DE 10 2004 013 994 A1), or, as an alternative, braking magnets  30  can be provided, at least partially, with permanent magnets (see e.g. patents applications DE 10 2007 025 793.8 and DE 10 2007 034 939.6 from the same applicant, which have not been published yet). In addition, the braking magnets themselves can have any design, and can also be provided with claw-pole configurations. 
     While  FIG. 2  shows the design, according to the invention, of driving- and braking magnets in a magnetic levitation vehicle  1  that includes a nose-side end  2  as one end section,  FIG. 3  shows a schematic depiction of a magnetic levitation vehicle  31  comprising a front end section  32 , a center section  33 , and a rear end section  34 , wherein magnetic levitation vehicle  31  can travel in the direction of arrow v and in the opposite direction. While end sections  32  and  34  are preferably designed similar to magnetic levitation vehicle  1  depicted in  FIG. 2 , central section  33  preferably contains identically designed magnet units  35 . They are designed e.g. similar to magnet units  16  and  26  in  FIG. 2 , but with the difference that, in the present embodiment, driving magnetic coils  36  are disposed exclusively in the lower plane of installation sites, and braking magnets  37  are disposed exclusively in the upper plane of installation sites. The same applies in  FIG. 3  for the driving- and braking magnets of the front and the rear end sections  32  and  34 , respectively. As a result it should be shown that the planes in which the driving- and braking magnets are disposed can be selected depending on the requirements of the individual case. 
       FIG. 3  furthermore shows that, in central section  33 , all installation sites of the lower plane are preferably occupied by driving magnet coils  36 , thereby ensuring that they form a band of continuous magnetic flux. In addition, all magnet units  35  are equipped with at least one braking magnet  37  each in this case. As a result, it is possible to design all magnet units of the entire vehicle to be identical, except for magnet units  15  disposed on nose-side ends  2  ( FIG. 2 ), if this is advantageous for reasons of redundancy or other reasons e.g. due to load requirements. 
     If it is desired to provide further center sections between end sections  32 ,  34  depicted in  FIG. 3 , their driving- and braking magnet units are all advantageously designed similar to magnet units  35  of center section  33 . 
     To prevent an interruption in the band of magnetic flux formed by the driving magnets also in transition regions  38  between two sections, as indicated by vertical lines ( FIG. 3 ), then, according to an embodiment that is currently regarded as being the best, further magnets  39 , which are designed e.g. similar to magnet units  35 , are disposed there. For this reason, magnet units (e.g.  35   a ,  35   b ) can also be provided directly at the ends of the particular sections that are adjacent to transition regions  38 , driving magnet coils  36  of which are disposed in a plane i.e. magnet units corresponding to magnet units  15  ( FIGS. 1 and 2 ) can be avoided here (see also DE 10 2004 056 438 A1). 
     A different number and placement of braking magnets  30 ,  37  can be selected. While braking magnets  30  depicted in  FIG. 2  are provided only in magnet units  16 ,  36  installed between two levitation chassises  3 ,  4  and  4 ,  5 ,  FIG. 3  shows that braking magnets  37  can also be disposed within one levitation chassis (e.g.  40 ) or within the levitation chassis and between two levitation chassises (e.g.  40 ,  41 ). In addition, braking magnets  30 ,  37  can be installed in all or only selected installation sites  23  of the various magnet units. An advantageous combination is therefore made possible. A first embodiment for the design and configuration of a magnet unit  43 , according to the invention and which is equipped with driving magnets and braking magnets, is depicted schematically in  FIGS. 4 and 5 . 
     Magnet unit  43  contains, in a lower plane, a plurality of cores  44 , which have e.g. a U-shaped cross section and two legs  44   a  and  44   b , and extend in the longitudinal direction and direction of travel of magnetic levitation vehicle, the exposed end faces of which lie in a plane that defines a guide gap  46  situated between magnet unit  43  and a lateral guide rail  45 . A segment part  44   c  of cores  44 , which connects each leg  44   a  and  44   b , is enclosed by a coil  47  that forms one of the above-described driving magnet coils  20  through  22 ,  27 ,  28 ,  36 . In this regard, the lower plane of magnet unit  43  corresponds to the lower plane of typical magnet configurations (e.g., DE 10 2004 056 438 A1, FIGS. 4 and 5) that are normally provided with driving magnet coils in two planes. In contrast, in an upper plane, magnet unit  43  comprises a plurality of magnet poles, which are disposed one after the other in the longitudinal direction or direction of travel, are preferably interconnected by a pole back, and each of which contains a core  48  and a winding  49  surrounding it. Various windings  49  are connected electrically in series and are connected to a direct-current source in a manner such that alternating magnetic north and south poles result. In the upper plane, magnet unit  43  therefore corresponds substantially to a common braking magnet (e.g. DE 10 2004 013 994 A1, FIG. 3). 
     According to a second embodiment depicted in  FIGS. 6 and 7 , a magnet unit  50 , according to the invention, in the lower plane is designed similar to that depicted in  FIGS. 4 and 5 , while a braking magnet disposed in the upper plane is formed of claw poles. For this purpose, core  44  has an E-shaped cross section, and lower legs  44   a ,  44   b  and coils  47  are designed as shown in  FIGS. 4 and 5 , while a third leg  44   d  is disposed such that it has mirror symmetry to leg  44   a  relative to a central plane of core  44 . A segment part  44   e , which is continuous in the longitudinal direction, similar to segment part  44   c  between legs  44   b  and  44   d , is enclosed by a coil  51 . It is energized by direct current in the direction opposite to that of coils  47 , and therefore legs  44   d ,  44   b  have magnetically opposite polarities. Claws  52  and  53 , which alternate in the longitudinal direction, extend away from legs  44   b ,  44   d , have alternating magnetic polarities, and, similar to the exposed ends of legs  44   a ,  44   b  and  44   d , are situated opposite guide rail  45 , forming guide gap  46 . Claws  52 ,  53  therefore form braking magnetic poles that corresponds to braking magnetic poles  48 ,  49  according to  FIGS. 4 and 5 . 
     The present invention is not limited to the embodiments described, which could be modified in various manners. This applies, in particular, to the means used to provide the installation sites for the driving- and braking magnets, and for the size, number, and design of driving- and braking magnets provided in the individual case. Furthermore, it can be advantageous to provide the driving- and/or braking magnets exclusively in more than one plane each. This would not change anything about the design according to the invention, according to which the driving magnets form a continuous band of magnetic flux, and the braking forces are distributed among a plurality of smaller braking magnets instead of one large braking magnet. Furthermore, it is clear that the number of magnet units disposed one behind the other in the longitudinal direction of the vehicle is not limited to the numbers shown in  FIGS. 2 and 3 , but rather can be varied within wide limits. The same applies for the number of driving- and braking magnets provided per magnet unit. In addition, the invention relates in an analogous manner to magnetic levitation vehicles that are equipped on both sides with a substantially identically designed driving- and braking magnet system as described above, or in the case of which the driving- and braking system is disposed only along a central axis of the vehicle. Finally, it is understood that the features described may also be used in combinations other than those described and depicted herein.