Protection for armature of electromagnetic linear drive

Abstract

An electromagnetic linear drive for driving a rail-guided vehicle along a rail system comprises at least one stator section (1) arranged at the rail system and at least one magnet armature (2) arranged at the vehicle. At least one magnet armature (2) comprises a cover (3) comprising a synthetic material comprising a web of carbon fibers and / or aramid fibers. The electromagnetic linear drive can be advantageously used in a roller coaster for driving a vehicle of the roller coaster.

Description

Technical Field

[0001] The present invention relates to an electromagnetic linear drive for driving a track-guided vehicle along a track system; in particular, the present invention relates to an electromagnetic linear drive for accelerating a ride vehicle of a roller coaster or other amusement ride. Background Art

[0002] A linear drive or linear motor is an electromagnetic propulsion engine that uses magnetic force generated by a magnetic field to drive an object along a straight or curved path. Unlike common rotary electric drives in which the rotational force is generated by a stable stator and a rotor arranged at the rotating object, the armature is arranged at the moving object to interact with the stator segments arranged along the path and generate a driving force when the object passes by the stator segments.

[0003] A well-known application of such an electromagnetic linear drive is a roller coaster. Typically, a roller coaster train is ejected into a track system made of steel every few minutes by an electromagnetic linear drive. The roller coaster train is heavy and receives its initial energy on, for example, a catapult track of about 50 meters in length via about 100 pairs of linear induction motors, commonly referred to as LIMs. Such LIMs are a further development of contactless acceleration systems based on the technology of rotary electric drives, with the aim of achieving mechanical maintenance-free operation to a large extent. LIMs are also used for mechanical drives of door systems, such as, for example, door systems in supermarkets, or for passenger conveyor belts and baggage belts at airports. LIMs have limited efficiency due to eddy current losses and temperature losses.

[0004] To achieve higher performance, linear induction motors are replaced by linear synchronous motors, commonly referred to as LSMs, which have a relatively higher efficiency than LIMs. Leading roller coaster suppliers usually rely on powerful LSMs to accelerate roller coasters, which can reach a top speed of around 180 kilometers per hour.

[0005] In general, an electromagnetic linear drive includes a stator coil arranged along a linear route, such as a track system, and the armature is arranged in a straight line at the vehicle. If an electric current passes through the stator coil, a magnetic field is generated around the stator coil. The magnetic field strength of the magnetic field depends on the applied current. In an electromagnetic linear drive, many such stator coils are connected in a row over the entire acceleration section or ejection section. The stator coils are grouped around the linear air gap. For example, the electromagnetic linear drive has a length of about 1 meter to 5 meters along the route. The magnetic active armature is positioned along the vehicle as a reaction track, which is pulled through the stator gap without contact by the electromagnetic linear drive. The working principle of the drive follows the law of induction. The applied AC voltage generates a magnetic field in the stator coil with a polarity that changes constantly between the north pole and the south pole, which moves along the length of the stator group. The travel field moves along the acceleration section, and the travel speed of the travel field is determined by the frequency of the applied current.

[0006] LIM systems typically use, for example, copper-based armatures or aluminum-based armatures. The traveling magnetic field applied in the stator induces a voltage in the armature track, which causes the free electrons in the armature material to move. This flow of electrons in turn produces a magnetic field. The two magnetic fields interact with each other, with opposite poles attracting each other and like poles repelling each other. The interaction of the two magnetic fields produces a force component in the direction of the traveling field, which causes the vehicle to move. In contrast, the armature of an LSM system is typically designed as a series of permanent magnets along a reaction track, which provide a constant magnetic field with alternating polarity. The armature magnetic field interacts synchronously with the traveling magnetic field generated by the stator group and produces a translational force; the armature glides (surfing) on ​​the magnetic waves of the stator group. The speed of the vehicle can be controlled synchronously with the speed of the traveling stator magnetic field.

[0007] EP 3 923 444A1 discloses a known concept of an electromagnetic linear drive, which is used to accelerate a vehicle in an acceleration section of a route. The electromagnetic linear drive is particularly suitable for accelerating a passenger vehicle in an amusement ride such as a roller coaster. The electromagnetic linear drive includes a stator having multiple pairs of stator elements arranged along the route section, which are combined into a stator group. In addition, the electromagnetic linear drive includes a magnet armature attached to the vehicle. In order to improve performance, the armature includes a permanent magnet to achieve acceleration force. The stator group is connected to an energy converter for energy supply, which can be controlled separately. In this example, at least two of the stator groups are arranged so that the magnet armature can interact with the two stator groups at the same time.

[0008] Currently, electromagnetic linear drives allow vehicle speeds of up to 150km / h-180km / h. However, the demand for higher vehicle speeds and accelerations, especially for roller coasters, is growing. Higher speeds and the associated higher frequency currents lead to higher eddy current losses in the components, especially in the magnet armature mounted on the vehicle. In addition, higher speeds lead to increased temperatures in the components of the electromagnetic linear drive, which leads to inefficient drive operation. As the magnetic forces increase during operation of the electromagnetic linear drive, the magnet armature may attract dust or particles along the track system, which may damage the stator segment during the next acceleration or deceleration phase of the vehicle.

[0009] In the prior art, it is known to use non-magnetic stainless steel or aluminum covers for the armature. Stainless steel covers serve in particular as mechanical protection. However, high eddy current losses can occur in the cover material, which also lead to temperature increases. This temperature increase in the cover can also increase the temperature of the armature surrounded by the cover. This again has a negative impact on the performance of the electromagnetic linear drive, especially in the case of permanent magnet LSM systems. In addition, the high eddy current losses can have a negative impact on the partly safety-related passive eddy current braking function of the drive.

[0010] DE 100 26 985A1 discloses a LSM system with an armature unit, which is called a secondary part, and the secondary part includes a carrier material made of carbon reinforced plastic, which provides an enclosure for the permanent magnet of the armature. The permanent magnet is directly placed in the enclosure constructed at the secondary part and cast therein. The secondary part made of carbon reinforced plastic and provided for the enclosure of the permanent magnet to be sealed therein is intended to avoid the driving force of the linear synchronous drive from being reduced. In addition, such a secondary part is intended to help avoid the deformation of the secondary part, which is caused by the lateral force caused by the magnetic interaction with the primary part on the large surface area of ​​the secondary part. However, the design of the carrier material of the secondary part as a carbon reinforced plastic material requires further structural adjustments to the drive system, which may affect the quality of the vehicle, first affecting the safety of the vehicle. Once the permanent magnet is cast in the enclosure of the secondary part, the permanent magnet cannot be touched to carry out the maintenance of the electromagnetic linear drive.

[0011] It is also known to use fiber reinforced plastics for rotary electric drives, where, due to the centrifugal forces acting on the rotor magnets, as the rotor speed increases, it becomes increasingly problematic to mount the magnets at the rotor. For example, in US 6,452,301 B1, radial retention of the rotor magnets and the slotted wedges between the rotor magnets is ensured by surrounding the entire cylindrical outer surface of the rotor with an outer sheath containing a fiber-reinforced organic or inorganic polymer composite material. The composite material is made by dry resin transfer and wet resin transfer (dry-laying resin transfer and wet) or prepreg filament process. In this way, the composite housing is formed with a containment wall that offsets the centrifugal forces generated by the magnets and wedges and allows higher speeds. Similarly, in such an embodiment, the magnets are inaccessible and it is complicated and expensive to install a protective cover on the magnets. Therefore, this solution is suitable for small rotary electric drives. This solution is not suitable for electromagnetic linear drives with magnetic armatures designed as large elongated reaction tracks, where the magnets are subjected to linear translation forces but not to rotational accelerations that generate centrifugal forces. Summary of the invention

[0012] The object of the present invention is to provide an electromagnetic linear drive and a cover for an armature of the electromagnetic linear drive, which cover increases the efficiency of the drive, in particular reduces eddy current losses during operation of the drive, provides a stable, light and flexible structure, and allows cost-effective production. In particular, the object of the present invention is to provide a roller coaster with an electromagnetic linear drive, which withstands wear and tear during operation and improves the performance of the roller coaster.

[0013] According to the invention, these and other objects are achieved in particular by an electromagnetic linear drive for driving a track-guided vehicle along a track system, an armature cover for such an electromagnetic linear drive, and a roller coaster having such an electromagnetic linear drive, which comprises the features of the independent claims. Furthermore, further advantageous embodiments can be derived from the dependent claims and the associated description.

[0014] According to one aspect of the present invention, an electromagnetic linear drive for driving a track-guided vehicle along a track system is provided, the electromagnetic linear drive comprising at least one stator segment arranged at the track system and at least one magnet armature arranged at the vehicle. The stator segment of the electromagnetic linear drive can be implemented as a stator segment of a track system that guides the vehicle. For example, the stator segment can be implemented as a group of stator pairs arranged along an elongated section of the track system and providing a gap for receiving the magnet armature. The group of stator pairs generates a magnetic field with a continuously changing polarity, which moves along the length of the stator segment and interacts with the magnet armature arranged at the vehicle. In the case where the electromagnetic linear drive is a LIS system, the magnet armature can be implemented by an induction unit, for example, by an induction unit made of copper or aluminum, which is excited by the alternating magnetic field of the stator segment. In the case where the electromagnetic linear drive is a LSM system, the magnet armature can be implemented as a permanent magnet arranged with alternating polarity along the vehicle and interacting with the alternating magnetic field of the stator segment. In both cases, the magnet armature defines an elongated reaction track that interacts with the stator segment.For example, the stator segment at the track system may include 4 to 50 stators, and the reaction track at the vehicle may include 1 to 50 magnet armatures.

[0015] According to the present invention, at least one magnet armature includes a cover comprising a synthetic material, the synthetic material including a mesh of carbon fibers and / or aramid fibers. The cover provides mechanical protection for at least one magnet armature. The synthetic material does not interact with the current and magnetic field used in the electromagnetic linear drive. The cover avoids the occurrence of eddy current losses and improves the efficiency of the electromagnetic linear drive. Carbon fibers have favorable physical properties to support the synthetic material of the cover. Carbon fibers are very strong, have high thermal conductivity, high chemical resistance and low thermal expansion. Aramid fibers are tough and soft, non-conductive, have high wear resistance and low flammability. Providing carbon fibers and / or aramid fibers as a mesh also enhances the stability and rigidity of the cover without adding too much weight to the synthetic material. Although the cover is lightweight, it is strong enough to prevent the magnet armature from any destructive impact during the rapid travel of the vehicle along the track system. In particular, in the case of a permanent magnet armature, the cover provides excellent protection because the permanent magnet is made of brittle materials such as rare earth elements that are easily corroded. Furthermore, the cover protects the stator segments because the synthetic material of the cover with the fiber mesh reduces the possibility of the magnet armature picking up particles along the ride and carrying them into the stator segments because the cover itself is not magnetic. During the acceleration phase of the electromagnetic linear drive, the cover does not increase in temperature like a commonly used metal cover and therefore no cooling system is required to cool the magnet armature protector. The shape of the cover can be adapted to match the shape of at least one magnet armature. Alternatively, the size of the cover can be selected to cover multiple or all magnet armatures of the reaction track.

[0016] According to another aspect of the invention, there is provided a magnet armature cover for an electromagnetic linear drive as described herein.

[0017] According to yet another aspect of the present invention, there is provided a roller coaster comprising the electromagnetic linear drive as described herein.

[0018] The carbon fiber and / or aramid fiber web of the synthetic material of the cover for the magnet armature can be realized, for example, by any arrangement of the fibers in the synthetic material. Preferably, the fibers are at least almost uniformly distributed in the synthetic material, wherein the number of fibers per unit area varies only slightly. In an advantageous variant, the fiber web is realized by a cross pattern of fibers, wherein the fibers extending in a first direction cross the fibers extending in a second direction, and the second direction is at an angle to the first direction. Of course, there may be fibers extending in a third direction or other directions at an angle to the first and second directions. For example, the web may include at least one first layer of at least nearly parallel fibers extending in a first direction and at least one second layer of at least nearly parallel fibers extending in a second direction and overlapping with the first layer. These layers can be realized as fiber sheets. A plurality of sheets can be continuously offset from each other along the length of the cover, which results in an expansion of the surface area covered by the sheets. In addition, the fiber web can be realized by a woven web, wherein the carbon fiber threads are interwoven to form a grid or woven fibers.

[0019] The mesh of the electromagnetic linear drive comprises carbon fibers and / or aramid fibers, such as ordinary carbon fibers or ordinary aramid fibers. In addition, the mesh of the synthetic material can be realized by a mixture of carbon fibers and aramid fibers. Aramid fibers contribute to the overall favorable physical properties of the cover because they have different physical properties from carbon. Aramid fibers can make up for the low mechanical stability of carbon fibers and compensate for the electrical conductivity of carbon. A mesh comprising a mixture of carbon fibers and aramid fibers can enhance the protection of the magnet armature and improve the efficiency of the electromagnetic linear drive.

[0020] In a variation of the carbon / aramid fiber web, the ratio of carbon fiber to aramid fiber in the blend ranges from 0: 1 to 1: 0. These blend ratios maximize the utilization of the advantageous properties of each type of fiber while minimizing the impact of properties that contribute less to the target of the cover.

[0021] According to another embodiment of the invention, the cover comprises a thickness between 2.0 mm and 0.5 mm, preferably between 1.2 mm and 0.8 mm, advantageously 1.0 mm. This thickness allows a strong fiber mesh structure to be incorporated into the synthetic material of the cover without affecting the design of the magnet armature for the layout of the electromagnetic linear drive.

[0022] In one embodiment variant of the electromagnetic linear drive according to the invention, the magnet armature is attached at the vehicle surface and the cover is attached to the vehicle surface above the magnet armature. The magnet armature can be fixed to the vehicle surface in a conventional manner, for example using screws or the like. The magnet armature can also be attached to the vehicle surface using a retainer incorporated in the surface. The cover is attached to the vehicle surface separately from the magnet armature and encloses the magnet armature. The cover can be fixed to the vehicle surface in a conventional manner, for example using screws or the like. Advantageously, the cover comprises an open side portion, which is closed by attaching the cover to the vehicle surface.

[0023] In an alternative embodiment variant of the electromagnetic linear drive according to the invention, the cover completely covers the magnet armature and / or the magnet is cast inside the cover. Thus, the magnet armature and the cover constitute a unit that can be attached to and removed from the vehicle to facilitate replacement or inspection of the magnet armature. The cover can have a form fit that is adapted to the shape of the magnet armature. In addition, the magnet armature can be held in the cover with a press fit. To this end, the interior of the cover can include compressible retaining elements, which are shaped according to the outer contour of the magnet armature when the magnet armature is pressed into the interior of the cover. In addition, the cover can accommodate more than one magnet armature.

[0024] According to another embodiment of the present invention, the cover can be sealed, for example, by a synthetic resin. The seal protects the interior of the cover from moisture. The synthetic resin can be applied only to the seams of the synthetic material and / or the connections of the magnet armature unit to completely seal any possible entrance to the interior of the cover. Alternatively, all free spaces between the magnet armature and the inner wall of the cover can be sealed with a synthetic resin. For example, the entire interior can be completely filled with a sealant material or a potting material by vacuum filling. In this case, the magnet armature and the cover are designed as a block unit, which does not have any free space for absorbing moisture. In addition, the block structure leads to improved mechanical stability. Multiple block units can then be attached to the vehicle to realize a reaction track.

[0025] In an advantageous embodiment of the invention, the electromagnetic linear drive according to the invention is designed as a linear synchronous motor. Preferably, the magnet armatures are realized as permanent magnets and groups of magnet armatures are arranged in a straight line at the vehicle, wherein each of the magnet armatures comprises a cover comprising a synthetic material, which comprises a carbon fiber or a carbon / aramid fiber mesh. The cover made of synthetic material with carbon fiber or carbon / aramid fiber mesh is particularly beneficial for LSM systems with elongated reaction rails located at the vehicle. The shape of the cover can be easily adapted to the shape of the permanent magnets of the LSM and even to the shape of the individual attachment areas at the vehicle. The cover protects the heavy permanent magnets without adding additional weight and is strong enough to keep the magnets safe and in place.

[0026] However, covers containing composite materials including carbon fiber, aramid fiber or carbon / aramid fiber mesh are also suitable for LIM systems using, for example, electromagnets as magnet armatures. The covers do not contribute to any significant eddy currents and protect the magnet armature from negative temperature effects.

[0027] In summary, magnet armature covers made of carbon or carbon / aramid blend woven reinforced plastic or synthetic materials make electromagnetic linear drives more efficient and extend their life. This material selection makes it possible to make mechanically very stable and light covers that are also non-magnetic and allow only few or no eddy currents to form. This results in stable mechanical protection of the magnet armatures covered by the covers, especially permanent magnets that are sensitive to vibration and shock, because these magnet armatures are made of brittle materials. The substantial reduction in eddy current losses in the covers improves motor efficiency and safety. These new covers can be tightly mounted on the vehicle base carrier that holds the permanent magnets and can be sealed to prevent moisture inside the covers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Exemplary embodiments of the present invention will be illustrated in the following drawings, which are for explanation only and should not be interpreted as limiting. The features of the present invention that become apparent through the drawings should be considered as part of the disclosure of the present invention, whether alone or in any combination. The drawings show:

[0029] Figure 1 is a schematic diagram of a cover for a magnet armature of an electromagnetic linear drive according to the present invention, and

[0030] Figure 2 is a schematic diagram of an electromagnetic linear drive according to the present invention, which illustrates a stator segment and a reaction track of the electromagnetic linear drive. DETAILED DESCRIPTION

[0031] The present invention provides an electromagnetic linear drive for driving a track-guided vehicle along a track system, the electromagnetic linear drive comprising at least one stator segment 1 arranged at the track system and at least one magnet armature 2 arranged at the vehicle. The magnet armature 2 comprises Figure 1 The illustrated cover 3 is made of a synthetic material including carbon fibers and / or an aramid fiber mesh. Figure 2 By way of example, two stator segments 1 and 1 ′ and a series of magnet armatures 2 covered by a cover 3 are shown.

[0032] For the sake of simplicity, the installation of the electromagnetic linear drive and other components of the system, such as the vehicle, the track system or the control system, are omitted in the figure. The electromagnetic linear drive according to the present invention can be based on the teaching disclosed in EP 3923444 A1, for example. Any description of the features of the electromagnetic linear drive disclosed in this article should be part of the present description of the electromagnetic linear drive according to the present invention.

[0033] like Figure 1 As shown, an example embodiment of a cover 3 for a magnet armature comprises a square shape with a large bottom surface 4 and a narrow circumferential surface 5. The top side of the cover may be open and may be closed after the magnet armature is located inside the cover. Note that the expressions "top" and "bottom" refer to the top and bottom of the cover. Figure 1 The orientation of the cover is illustrated and should not be construed as a limiting feature of the cover. In another perspective view of the cover, the bottom surface may be located at the top, while the bottom may be open. The volume of the cover 3 is adapted to the outer contour of the magnet armature to be enclosed by the cover. The circumferential surface 5 includes a through hole 7 along the upper edge, which can be used for fixing devices, such as screws, for fixing the magnet armature to the interior of the cover and / or for attaching the cover with the magnet armature inside to the vehicle. In addition, the through hole 7 can be used to inject sealing material into the interior of the cover.

[0034] Once the magnet armatures are inside the cover, they can be attached to the vehicle as a unit, wherein the surface of the vehicle serves as the attachment surface. The cover can completely enclose the magnet armature, or the cover can be closed by attaching the magnet armature to the vehicle. The edges of the circumferential surface 5 resting on the vehicle surface can be sealed, and / or the interior of the cover can be filled with a sealing material and / or a potting material through the through holes 7 for sealing.

[0035] The surface of the cover comprises a synthetic material comprising a web of fibers or an aramid web of fibers or a web of a mixture of carbon fibers and aramid fibers. As is well known, the cover can be produced, for example, by using a casting mold that determines the shape of the cover and adding the web of fibers and synthetic materials to the casting mold.

[0036] Figure 2 The arrangement of the stator segments 1 and 1' and a group of magnet armatures 2 of the electromagnetic linear drive is schematically illustrated. Each magnet armature in the magnet armature includes a cover as described above. The magnet armatures 2 are arranged in pairs to provide a gap 8 between them. In addition, the magnet armatures 2 are arranged in a straight line at a vehicle (not shown). The group of paired magnet armatures 2 defines a reaction track of the electromagnetic linear drive. The stator segments 1 and 1' are attached in series along a track system, which serves as a guide for a vehicle carrying the magnet armatures 2. In order to drive a vehicle including the magnet armature 2, the vehicle is positioned on the stator segments 1 and 1' or travels on the stator segments 1 and 1'. The stator segments 1 and 1' pass through the gap 8 between the paired magnet armatures 8. As described above, the alternating magnetic field traveling along the stator segments 1 and 1' interacts with the alternating magnetic field generated by the group of magnet armatures 2 and generates an acceleration force on the vehicle.

[0037] The roller coaster described in the international patent application number PCT / EP2022 / 072383 of the present applicant can be used as the basis of the roller coaster according to the present invention. The features of the roller coaster described therein should be incorporated into this specification. The track system is arranged on a support structure consisting of a plurality of elongated support elements. The support elements are arranged substantially vertically on a base on which the roller coaster is arranged. On the track system, a vehicle is shown as an example, which may contain a plurality of individual cars. The roller coaster has a linear synchronous drive. For this purpose, a plurality of stators are arranged along the track on the track system, thereby forming a stator section, and a plurality of magnet armatures are arranged on the vehicle, and a plurality of magnet armatures generate a driving force for the vehicle by induction. The roller coaster also has: a central control unit, which controls the driving operation of the linear synchronous drive; and an energy supply system, which is used to provide energy for the linear synchronous drive and the control system. According to the present invention, each of the magnet armatures of the roller coaster includes a cover comprising a synthetic material, which includes a carbon fiber mesh or an aramid fiber mesh as described above, or a mesh of a mixture of carbon fiber and aramid fiber.

[0038] In the patent claims, the words "comprise" and "comprising" do not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. A single unit step may fulfill the functions of several features recited in the claims. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

[0039] Reference numerals

[0040] 1. 1' stator section

[0041] 2 magnet armature

[0042] 3 Covering

[0043] 4 Bottom surface

[0044] 5 Circumferential surface

[0045] 6---

[0046] 7 Through Holes

[0047] 8 Clearance

Claims

1. An electromagnetic linear drive for driving a track-guided vehicle along a track system, the electromagnetic linear drive comprising at least one stator segment (1) arranged on the track system and at least one magnet armature (2) arranged on the vehicle, wherein: The at least one magnet armature (2) comprises a cover (3) comprising a synthetic material including a mesh of carbon fibers and / or aramid fibers.

2. The electromagnetic linear actuator according to claim 2, wherein: The web is realized by a mixture of carbon fiber and aramid fiber, and the ratio of the carbon fiber to the aramid fiber in the mixture is in the range of 0:1 to 1:

0.

3. The electromagnetic linear drive according to claim 1, wherein: The cover (3) is sealed by synthetic resin.

4. The electromagnetic linear drive according to claim 1, wherein: Said cover (3) comprises a thickness between 2.0 mm and 0.5 mm, preferably between 1.2 mm and 0.8 mm, advantageously 1.0 mm.

5. The electromagnetic linear drive according to claim 1, wherein: The at least one magnet armature (2) is designed for attachment at a surface of the vehicle, and the cover (3) is designed for attachment to the surface of the vehicle and covering over the magnet armature (2).

6. Electromagnetic linear drive according to one of the preceding claims 1 to 5, wherein: The cover (3) completely covers the magnet armature (2).

7. The electromagnetic linear drive according to claim 1, wherein: The cover (2) holds the magnet armature (2) and includes one side portion which is open and is closed by attaching the cover (3) to the surface of the vehicle.

8. The electromagnetic linear drive according to claim 1, wherein: The at least one magnet armature (2) is realized as a permanent magnet.

9. The electromagnetic linear drive according to claim 1, wherein: A group of magnet armatures (2) are arranged in line at the vehicle, and each of the magnet armatures (2) includes a cover (3).

10. The electromagnetic linear drive according to claim 1, wherein: The linear drive is a linear synchronous motor.

11. A magnet armature cover (3) for an electromagnetic linear drive according to one of the preceding claims.

12. A roller coaster comprising an electromagnetic linear drive according to one of the preceding claims.

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