The present invention relates to an elevator comprising at least one elevator car driving in an elevator shaft. The elevator car has at least one elevator car door, which is slidably supported at the elevator car. The elevator further comprises a car door drive mounted at the elevator car for driving at least one car door motor as to move the car between its opening and closing position. The car door motor is a linear motor with at least one linear stator rail and a mover which is designed to co-act with the stator rail. An elevator according to this known background of the invention is known from US 5,949,036. In this elevator, a mover having two active parts is co acting with stator rails mounted to the car leaves or car door, respectively.

It is object of the present invention to improve the above-mentioned type of elevator.

The object of the invention is solved with an elevator according to claim 1. Preferred embodiments of the invention are subject-matter of the dependent claims.

According to the invention, the car door motor is a flux switching permanent magnet motor unit having its stator rail being mounted to the elevator car and the mover being mounted to the car door. The arrangement of the mover(s) in connection with the car door(s) and the fixing of the stator rails to the elevator car has the advantage that the alignment of the stator rail in horizontal direction parallel to the door plane can be easily achieved by fixing the corresponding stator rail at the elevator car preferably at the top of the elevator car above the car door opening. Preferably, also a stator rail could be located below the car door opening if it is intended to provide a driving mechanism on the top as well as on the bottom of the car door. In this case, the mover is fixedly connected to the car door preferably at the top of the car door and optionally also at the underside of the car door. If the car door has two moving car door leaves, which move together in a telescope manner or in opposite directions, whereby each car door leaf has its own mover, so that both movers are running along the same stator rail(s). This has the advantage that only one stator rail is necessary on which the movers for both car door leaves are running.

In a preferred embodiment of the invention, the stator rail is mounted to a stator beam which is supported at the elevator car. The provision of a stator beam supporting the stator rail has the advantage that the whole arrangement is more rigid and a stator beam allows the mounting of several mutually parallel stator rails for example on different or opposite sides of the stator beam. Thus, the stator beam may be rectangular or square in which case on each side of the rectangular or square profile, a stator rail may be located. Of course, also a triangular cross-section of the stator beam is possible in which case three stator rails can be carried by it. The provision of several parallel stator rails in connection with the stator beam has the advantage that the driving force could be multiplied as each mover may carry a number of active parts corresponding to the number of stator rails supported by the stator beam. Thus the FSPM motor unit may have a number of parallel motors corresponding to the number of active parts of the mover. Thus, either the size of the mover can be reduced or the driving force of the linear motor can be increased which may be relevant if for example heavy car doors and floor doors have to be moved by the car door motor. In an optimized embodiment, the stator beam has a square profile with preferably four stator rails being located on each face of the square profile. Via the square profile it is easy to place stator rails of equal size on each face of the stator beam and such an arrangement facilitates the provision of a levitation control if the mover should not only move the car door but also support the car door instead of rollers.

Preferably, the mover comprises a U- or C-profile with the active parts located at the facing inner sides of the U- or C-profile. With such a profile, the stator rails located at the different faces of the stator beam can easily be encased by the corresponding active parts of the mover. With respect to the use of a stator beam with the square profile, the mover preferably has a C-profile with four inner faces arranged mutually rectangular particular square on which four inner faces the active parts of the mover are arranged, respectively.

Via this arrangement, a linear motor construction is achieved which is able to generate a high driving force for the movement of the doors as well as to provide the sufficient levitation force to carry the car door or car door leaves.

In a preferred embodiment of the invention, the FSPM motor unit comprises at least two parallel stator rails being immovable with respect to each other. Via this means, the mover may have two active parts co-operating with both stator rails which increases the motor power by factor 2.

Another option of this embodiment is that the two movers of two door leaves may run over the door opening length of one door leaf. This arrangement may for example be chosen if there is no place above one of the door leaves to arrange a mover there.

In that embodiment, preferably both movers each have an active side and a passive side facing the two stator rails, whereby the active and passive sides of both movers are opposite to each other. Thus each of the two stator rails forms together with the corresponding active part of a mover a separate FSPM motor unit.

In one embodiment of the invention, the car door or car door leaves of a car door is/are supported by rollers in a guiding track. In this case, the FSPM motor unit only needs to move the car door or car door leaves and doesn't need to support it as the support is provided via the rollers in the guiding track. Therefore, in this case it is sufficient that only one mover for each car door or each car door leaf is provided which is then preferably located at the upper end of the car door.

Preferably, in this case, the rollers are guided in the guiding track without essential play as to define the air gaps between the mover and the two stator rails. This transfers the whole guiding function to the mechanical roller arrangement so that the mover control can be reduced to simply move the car door or car door leaf. This embodiment is easy to realize. In this embodiment the mover may have two opposite active sides which co-act with the corresponding stator rails. Thus, in a preferred embodiment of the invention which is particularly advantageous in this case of a roller support of the car door or car door leaves, the FSPM unit comprises two or more active sides (FSPM motors) without yoke. In this case the active sides share the same active parts, i.e.

permanent magnets, windings and irons. This design is more space-efficient compared to the design of two FSPM motors with a yoke which are for example shown in Fig. 6 which is adapted for air gap control and levitation control via the active parts. Flowever, the simplified arrangement without yoke saves space in the elevator shaft between the elevator car and the landing door side of the shaft wall and therefore enables the use of the shaft more space-efficiently than for example by enabling the use of a larger elevator car. Furthermore, less material is required to manufacture the mover which reduces the manufacturing costs and makes the installation of the motor and door easier as the components which are to assemble are more lightweight. Additionally, the drive electrification supplying the motors may be designed for less peak power or current as the moving mass of the mover is smaller which leads to cheaper components. The acceleration of the movement of more lightweight movers requires less power and hence if the FSPM motor units are supplied from a car battery, the battery size may be smaller which also holds true for a backup energy supply.

In an alternative embodiment of the invention, the FSPM motor unit comprises a levitation control as to support the car door or car door leaf by the magnetic field of the FSPM motor unit without the necessity of using rollers. In this case, the linear FSPM motor unit combines the function of supporting the car door or car door leaf as well as to move it. If the mover having opposite active sides facing away from each other, they cannot share the active parts but a yoke has to be located between the active parts of both sides, which allows the both opposite active sides of the mover being controlled separately, which enables air gap control as well as levitation control.

In this case, the whole suspension of the car door can be reduced to the mounting of the stator rails at the elevator car and the movers at the car door, preferably at the upper as well as the lower end thereof so that the car door is supported by an FSPM motor unit at its upper end as well as at its lower end. Via this means, a secure suspension and movement of the car door or car door leaf is realized.

In a preferred embodiment of the invention, the car door drive comprises a backup energy supply so that in case of power off it is still possible to open the car door. In this case, preferably the backup energy supply is integrated in the linear FSPM motor unit which has the advantage that all components of the door drive are accessible from one working point.

Preferably, the backup energy supply is releasably connected to the mover body so that it can easily be replaced, e.g. by a snap-lock connection.

Preferably, also the car door drive is integrated in the FSPM motor unit which has the advantage that the control electronics with the power lines for driving the FSPM motor unit only needs short connections which reduce sensibility against outer influences as well as reduces sensibility against noise. Furthermore, the maintenance work as well as installation work with respect to the elevator car door can be performed in total from one working place which reduces installation as well as maintenance costs. Finally, this integrated arrangement allows a mover, i.e. its massive mover body forming a cooling element for the car door drive. Usually, the mover body comprises a voluminous metal casing forming a good heat sink for the control and power electronics of the car door drive which may produce some remarkable heat. Thus, with integration in the FSPM motor unit, the car door drive is always cooled sufficiently.

In a preferred embodiment, a floor door in the elevator shaft is during door opening and closing procedure mechanically coupled via at least one door coupler to the car door. This means that the linear FSPM motor unit moves or moves and supports the car door as well as moves the landing door. Particularly in this case it is advantageous that the FSPM motor unit comprises several stator rails which are mounted immovable with respect to each other. Preferably, in this case the closing movement of the floor door is supported by a closing weight which improves the safety of the elevator arrangement.

The mover has preferably a length of 100 to 300 mm, particularly from 150 to 250 mm which is optimized for the need of common movement of car doors and landing doors.

It should be clear for the skilled person that the above-mentioned embodiments can be mixed up with each other without delimitation.

Following terms are used in synonym : motor drive - car door drive; active side - active part;

The invention is now explained in an example by means of the schematic drawing . Flerein :

Fig . 1 shows an embodiment of an FSPM motor unit with two stator rails whereby the car door is supported by rollers,

Fig . 2 shows a similar arrangement to Fig . 1 whereby in this case, the FSPM motor unit comprises a levitation control, so that the car door is supported by the FSPM motor unit and does not need rollers for its support,

Fig . 3 shows a schematic front side of an embodiment with one FSPM motor unit at the top of the car door,

Fig . 4 shows a view according to Fig. 3 with two FSPM motor units, one at the top as well as one at the bottom of the car door,

Fig . 5 shows a schematic drawing of an FSPM motor unit comprising a mover with two active sides as well as two stator rails the mover being without yoke, which design is particularly used in connection with a roller support of mover and car door,

Fig . 6 shows a view according to Fig. 5 of an FSPM motor unit having a mover with two active sides designed for levitating the car door, whereby between the active parts of both sides a yoke is arranged for separately controlling both active sides, Figs. 7 to 9 show perspective drawings of an elevator car with a car door having two door leaves which are moved by a levitating FSPM motor unit at the top as well as at the bottom,

Fig . 8 shows a detail of Fig . 7 at the top,

Fig . 9 shows a detail of Fig. 7 at the bottom,

Fig . 10 shows a perspective view of a levitating FSPM motor unit comprising a stator beam having a square profile with four stator rails,

Fig . 11 shows a front view of the arrangement of Fig . 10,

Fig . 12 shows a more detailed perspective view of the mover and stator rail of Fig. 10,

Fig . 13 shows a detailed perspective view of the stator beam with four stator rails as used in any of Figs. 7 to 12,

Fig . 14 shows a perspective view from below to an FSPM motor unit with levitation function used in the arrangements of Figs. 7 to 13, and

Fig . 15 shows a schematic view more from the front of the stator rail and mover of Fig. 10 in a 90° tilted version.

Fig. 1 shows a vertical cut through the door support arrangement of an elevator car door in a plane perpendicular to the car door. The arrangement comprises a support bracket 10 with a horizontal beam 12 and two vertical beams 14, 16 building together a turned around U-profile. This support bracket 10 supports via its vertical arms 14, 16 two stator rails 20, 22 and above each stator rail 20, 22 a guide track 24 for a roller of the mover is preferably located or integrated on the top side of the stator rails 20, 22. The stator rails 20, 22 are forming together with a mover 26 an FSPM motor unit 28 for moving a car door 30 which is fixed to the lower end of the mover 26. The mover 26 comprises a mover casing 32 in which windings 34 and a permanent magnet 38 are located .

The mover 26 further comprises irons 40. The permanent magnets 38, the coils 34 as well as the irons 40 form the active part of the mover 26 co-acting with the stator teeth of the stator rails 20, 22. In the embodiment, the mover 26 has two opposite active sides which co-act with the facing sides of the two stator rails 20, 22. Rollers 42, 44 are mounted to the upper area of the mover casing 32, which rollers 42, 44 are running in/on the guide tracks 24 located above the stator rails 20, 22. The play of the rollers 42, 44 in the guide tracks 24 is minimized so that the air gaps agl, ag2 between the active sides of the mover 26 and the corresponding stator rails 20, 22 is equally large and constant over the whole running length of the mover in the guide tracks 24. In this arrangement, the car door 30 may additionally be guided at its lower end with a roller/guide track arrangement in a per se known way. Of course it is possible to provide the FSPM motor unit as shown in Fig . 1 also at the lower end of the car door 30 in which case the arrangement is essentially mirrored around a horizontal plane. Fig. 2 shows a similar arrangement to Fig. 1 whereby identical parts are designated with the same reference numbers. In contrast to Fig. 1, the FSPM motor unit 50 with the mover 52 and the stator rails 20, 22 comprises a levitation control which not only moves the mover 52 in horizontal direction as to open and close the car door 30 but it also generates an upwards pulling support force for the car door according to the bold arrow in the figure so that this arrangement does not need rollers and a roller track for supporting the mover and the car door. Essential in this embodiment is that the windings 34a, b and the irons 40a, b are separated by a yoke 46 as to be controlled separately which enables levitation control as well as control of the width of both air gaps ag l, ag2.

Fig. 3 shows a front view of a car door 30 which is supported by an FSPM motor unit 28, 50 according to Fig. 1 or 2 at its upper end.

According to Fig. 4, an FSPM motor unit 28, 50 according to Fig. 3 is located at the upper as well as the lower end of the car door 30 so that the car door 30 is guided by the corresponding FSPM motor units 28, 50 with rollers or without rollers at the upper and lower end of the car door 30 which gives a good stability and guidance for the door support and the opening and closure movement of the car door 30.

Fig. 5 shows a horizontal cross-section through an FSPM unit 28, 50 as shown in Fig. 1 or 2, whereby this arrangement is particularly configured for an arrangement according to Fig. 1 where rollers are used . Flere, the mover 28, 50 has two active sides 60, 62 co-acting with the stator teeth 64 of the two stator rails 20, 22 so that the two active parts together with the associated stator rail 20, 22 forms its own FSPM motor whereby these two FSPM motors don't have a yoke, so that they can’t be controlled separately. This this arrangement doesn't allow the adjustment of the air gaps agl, ag2 via the active sides of the mover. This has to be done via a proper roller support of the mover together with the car door leaves as it is shown e.g. in Fig. 1. Flowever, this arrangement saves place, is easy to control and leads to a cheaper construction which is easier to install.

Fig. 6 shows a similar arrangement of an FSPM motor unit 28, 50 whereby the difference to Fig . 5 is the fact that between the two active sides 60 and 62 of the mover 28, 50, a yoke 68 is provided. Accordingly each active side 60, 62 of the mover 28, 50 forms an own motor with the

corresponding stator rail 20, 22, and both active sides 60, 62 can be controlled independently of each other. Thus, the air gaps agl and ag2 can be controlled with this arrangement and the thus built FSPM motor unit 28, 50 is particularly suited for additional levitating function (support of mover and car door on the stator rails or stator beam) as well as the moving function for the car door so that no rollers are necessary for mover support and car door support. Thus this motor design is particularly adapted for the Fig . 2 arrangement. In Fig .6 the windings 34a, 34b are separate, the irons 40a, 40b are separated by the yoke 68 but the permanent magnets 38 may be common to both sides, which simplifies the structure.

Fig. 7 shows an elevator car 80 having a roof 86 and a bottom 88 as well as side walls 87 and a car door 30 with two car door leaves 82, 84 moving in opposite directions to open and close a door opening 81. The upper and lower ends of the car door leaves 82, 84 are via screws 89 or similar connections fixed to movers 90 which are running on a stator beam 92 with a square profile 103 having four stator rails 104a,b,c,d at its circumference (see Fig. 10). The thus formed FSPM motor units 100 consisting of the movers 90 and corresponding stator beams 92 are more detailed described in the following Figs. 8 to 15. The following statements refer to all these figures, which show the same embodiment in different perspectives and views.

The upper stator beam 92a is located and fixed to the elevator car 80 in the area of the car roof 86 whereas the lower stator beam 92b is fixed to the elevator car in the area of the car bottom 88.

As it is shown in Fig. 10, the upper mover 90 comprises a downwards directed C-profile 102 which encompasses the four stator rails 104a-104d located at the outer faces of the square profile 103 of the stator beam 92a . The stator beam 92a has on its lower end a mounting part 106 connected to the square profile 103 at its corner via which mounting part 106 the stator beam 92 is mounted to the elevator car 80, e.g. on the roof 86 or the bottom 88 or at the side wall 87 above and below the door opening 81. The C-profile 102 of the mover 90 comprises at its inner sides separate active sides 112a-112d (see Fig . 14) facing and co-acting with the stator rails 104a-104d. In this case, the FSPM motor unit 100 essentially comprises four single FSPM motors having their motor force and torque added up so that the torque of this motor is fourfold the force as if only one stator rail 104 would act together with one active part of the mover 90. A further advantage of this solution is that the provision of four stator rails and the corresponding active parts easily allows the levitation of the mover 90 and car door leaf 82 and also the control of the air gaps between the stator rails 104a-104d and the corresponding active parts 112a-112d in the C-profile 102 of the mover 90.

Fig. 13 clearly shows the stator beam 92 consisting of the square hollow profile 103 and the mounting part 106 which is connected to an edge 105 to the square profile 103 between two stator rails 104c and 104d. The figure also shows the stator teeth 96 of the stator rails 104a- 104d .

According to Fig. 14, the mover 90 also comprises the car door drive 110 with the control and power electronics for driving the active parts on the four faces 112a-112d of the C-profile 102. A further advantage of this integrated solution is that the car door drive 110 comprises power electronics which are emitting a lot of heat which is effectively conveyed via the massive body 91 of the mover 90 which acts as a cooling element having outer cooling ribs 93. Furthermore, optionally also a backup energy supply 114 is integrated into the mover 90 of the FSPM motor unit 100 so that in case of power off, the car door drive further gets enough energy to finish an opening or closing movement. Preferably, the backup energy supply 114 is releasably connected to the mover body 91, e.g. via a snap-lock connection.

The provision of the stator beam 92 with a - particularly hollow - square profile 103 has the advantage that the stator beam 92 is very rigid so that the air gaps between the active sides 104a- 104d and the corresponding active parts 112a-112d of the mover can be easily kept and maintained by the control via the car door drive 110. The invention is not restricted to the shown embodiments but may be varied within the scope of the enclosed patent claims.

List of reference numbers:

support bracket

horizontal beam

, 16 vertical beams

, 22 stator rails

guide track for the roller

mover

FSPM motor unit

car door

mover casing

windings

permanent magnet

iron

, 44 roller

yoke

FSPM motor unit (second embodiment)

mover

, 62 active sides of the mover

stator teeth located on the stator rail co-acting with the active parts of the mover yoke

elevator car

door opening

, 84 car door leaves

car roof

side wall of the car

car bottom

fixings (screws) for connecting car door (leaf) and mover

mover

mover body

stator beam

cooling ribs of the mover body

stator teeth

0 FSPM motor unit

1 mounting part of the mover connected to the C-profile for the car door (leaf)2 C-profile of the mover

4a-d stator rails on the square profile of the stator beam

5 edge of the square profile being connected to the mounting part

6 mounting part of the stator beam

0 integrated car door drive

2a-d active sides of the mover

4 integrated and optional releasable backup energy supply agl air gap between stator rail and first active side of the mover ag2 air gap between stator rail and second active side of the mover