An Elevator Drive unit

The invention relates to a drive unit for an elevator.

A drive unit for a lift has become known from the specification EP 1 357 076 A1 , which substantially consists of end plates, a motor, a drive pulley and a brake. A shaft is supported by the end plates, wherein the motor, the drive pulley and the brake are arranged within the end plates or between the end plates. The end plates are supported at an engine frame. The rotor of the motor is carried by the shaft and the stator together with the windings is supported at the engine frame. The shaft also serves as a drive pulley, wherein the shaft has in the drive pulley region an enlarged diameter and grooves for receiving the support means.

The invention as characterised in claim 1 fulfils the object of creating a drive unit of simple and compact construction for a lift. 1 . In particular, the invention provides an elevator drive unit comprising two end plates, a motor having a stator and a rotor, a shaft supported between the end plates, the shaft carrying the rotor at an intermediate position and at least one traction zone positioned between the rotor and each end plate, and frame elements connected to the stator and the end plates, the frame elements supporting the stator at the intermediate position on the shaft and transmitting forces to the end plates.

Advantageous developments of the invention are indicated in the dependent patent claims.

The advantages achieved by the invention are substantially to be seen in that the drive unit according to the invention with drive frame is statically defined and stable and suitable for arrangement in the engine room or in the lift shaft. A wide range in terms of power can be covered by the proposed construction. Drive variables, whether a greater or smaller, lying outside this power range can be easily realised by changing a few parameters and masses with the same mode of construction. The drive shaft, which usually serves as drive pulley, can be readily changed in diameter depending on the needs of the support means. Thus, the drive unit can be used for different support means such as steel cables, steel cables encased in plastics material, aramide cables or belts with inserted steel cables or synthetic fibre cables, wherein for every kind of support means the minimum drive pulley diameter or shaft diameter thereof is desired. The provision of traction zones at either side of the motor balances the loading. In addition, it is advantageous that the

drive unit is easily adaptable to the lift layout and to the support means layout. In the case of lifts with 1 x 2 or 2 x 1 or 2 x 2 or n x m support means the position, which is desired by the drive layout, of the individual drive pulleys in the drive unit can be selected with the length of the drive shaft. For example, "2 x 1 support means " is to be understood in the sense that a support means is guided between motor and one end plate, and a support means is guided between motor and the other end plate, over the shaft or drive pulley. Accordingly, n signifies the number of shaft sections with drive pulleys and m signifies the number of drive pulleys per shaft section. In the symmetrical motor arrangement n = 2 and in the asymmetrical motor arrangement n = 1. A belt or several cables running in parallel can be provided as support means. In addition, the motor size can be changed in simple manner with the drive concept according to the invention. The stator as well as the rotor can be made larger or smaller in length and/or in width and/or in height. Depending on the respective space conditions between the end plates, the respective brake disc and the associated brake can be arranged inside or outside the respective end plate.

The drive unit according to the invention for a lift consists of end plates, a motor, a drive pulley and a brake, wherein a shaft carrying the rotor of the motor and the drive pulley is supported by the end plates and the motor and the drive pulley are arranged between the end plates and a drive frame consisting of the end plates and of frame elements connecting the end plates is provided, wherein the frame elements carry the stator of the motor and transmit the forces to the end plates.

The present invention is explained in more detail by way of the accompanying figures, in which:

Fig. 1 shows a symmetrical drive unit according to the invention with drive frame,

Fig. 2 shows a section through the symmetrical drive unit according to the invention,

Fig. 3 shows a variant of embodiment of the symmetrical drive unit,

Fig. 4 shows an asymmetrical drive unit according to the invention, with drive frame,

Fig. 5 shows a section through the asymmetrical drive unit according to the invention,

Fig. 6 shows the drive unit according to the invention with sectional plane,

Fig. 7 shows a section through the drive unit according to the invention and

Fig. 8 shows the drive unit according to the invention in exploded illustration.

Fig. 1 shows the drive unit 1 according to the invention with drive frame 2. In the illustrated variant of embodiment the drive frame 2, which spans a block, consists of a first end plate 3, a second end plate 4 and frame elements 5 connecting the end plates 3, 4, wherein a respective frame element 5 is provided at each longitudinal edge of the block. Further frame elements 5 can be provided between and parallel to the illustrated frame elements 5. The block can also have only a respective frame element 5 lying at two diagonally opposite longitudinal edges or two frame elements 5 lying on one block longitudinal side or a respective frame element 5 arranged at two opposite block longitudinal sides. The frame elements 5 also serve as supports for parts of a motor 6, for example an electric motor with rotor 7 and stator 8. A hydraulic motor or a pneumatic motor is also conceivable. A hood 9 covers the stator 8 on each side of the motor 6. The rotor 7 is arranged at a drive shaft 10, termed shaft 10 in the further course of description, and drives this. Shaft 10 and end plates 3, 4 are perpendicular to one another. The stator 8 is carried by the frame elements 5, which transmit the forces to the end plates 3, 4. A first bearing 1 1 mounts one end of the shaft 10 at the first end plate 3 and a second bearing 12 mounts the other end of the shaft 10 at the second end plate 4. The shaft 10 is constructed between first end plate 3 and motor 6 as drive pulley 13 for at least one support means (not illustrated) and is constructed between second end plate 4 and motor 6 as drive pulley 13 for at least one support means (not illustrated). A first brake disc 14, which can be braked by means of a first brake unit 15 arranged at the first end plate 3, is provided at the shaft 10 on the inner side of the first end plate 3. Provided on the inner side of the second end plate 4 at the shaft 10 is a second brake disc 16 which can be braked by means of a second brake unit 17 arranged at the second end plate 4. Each end plate 3, 4 is provided with plate feet 18 at which vibration dampers 19 are arranged. The vibration dampers 19 insulate the drive unit 1 in terms of vibration relative to a support construction (not illustrated). A section plane placed through the centre of the shaft 10 is denoted by A. The thus-generated section plane of the drive unit 1 is shown in Fig. 2.

Fig. 2 shows a section through the symmetrical drive unit 1 according to the invention. In

the symmetrical drive unit 1 the motor 6 is preferably centrally arranged between the end plates 3, 4. The motor 6 can, however, also be arranged somewhat displaced from the centre. The diameter D of the shaft is substantially uniform over the entire shaft length. However, the diameter D in the drive pulley region can depart from the diameter in the rotor region. Merely fine grooves 20, which are arranged at the shaft 10 and which, for example, receive longitudinal ribs of a flat belt as support means, are arranged as drive pulley 13. A respective flanged pulley which prevents the support means or flat belt from rising out of the grooves can be provided on either side of the grooves of a drive pulley. The diameter D can, for example, be 60 millimetres to 1200 millimetres. In the illustrated examples of embodiment the shaft 10 and the drive pulleys 13 are made of one piece. In the case of larger drive pulley diameters the drive pulley 13 can be placed as a separate component on the shaft 10. The minimum diameter D is predetermined by the kind of drive means. Steel cables as support means desire a substantially larger diameter D than aramide cables or flat belts with tensile carriers of plastics material. The rotor 7 driving the shaft 10 can be constructed as a synchronous rotor with permanent magnets or as a short- circuit armature or as asynchronous rotor. An air gap 21 is provided between the rotor 7 and the stator 8. The stator 8 carried by the frame elements 5 has windings 22 which are laid in grooves and covered by means of the hoods 9. Provided at each shaft end is a brake disc 14, 16 on which a brake unit 15, 17 acts in the case of braking. The brake unit 15, 17 substantially consists of a brake magnet 23, 25 which is arranged to be floating at the end plate 3, 4 and which when acted on by current actuates a brake armature 24, 26 and in that case acts against brake springs (not illustrated) and releases the brake.

The drive unit 1 of compact construction is suitable for arrangement in the engine room or lift shaft and has, in the case of 2 x 2 support means in the form of flat belts, for example a length L of 754 millimetres, a height H of 503 millimetres and a width B of 400 millimetres. Greater or smaller dimensions are also possible.

Fig. 3 shows the drive unit 1 according to the invention with brake discs 14, 16 arranged outside the end plates 3, 4 and at least two brake units 15, 17 per brake disc. The shaft 10 is prolonged beyond the end plates 3, 4 and the protruding shaft stubs 27 carry the brake discs 14, 16. The brake unit 15, 17 is furnished at least twice for each brake disc 14, 16, wherein a plate 28 connects and stabilises the two brake magnets 23, 25. Brake magnets 23, 25 acted on by current act against brake springs (not illustrated) and release the brake, wherein the brake disc 14, 16 is moved in axial direction. In the case of

braking, the brake disc 14, 16 is pressed by means of the brake springs against the end plate 3, 4. With the brake discs 14, 16 arranged outside the end plates 3, 4 more space for the two drive pulleys 13 is left between the end plate 3, 4 and the motor 6.

The frame elements 5 carry the stator 8, wherein the stator 8 has, for example, a weight of approximately 120 kilograms. In addition, the frame elements 5 have to transmit the torque generated by the motor 6, for example a starting torque of 950 Nm, to the end plates 3, 4 and withstand a braking torque of, for example, 1200 Nm. The drive frame 2 in that case may twist only to a minimum extent so that the size of the air gap 21 between stator 8 and rotor 7 is not impermissibly changed.

Fig. 4 and Fig. 5 show an asymmetrical drive unit 1 according to the invention with drive frame 2. The motor 6 is arranged at one end at an end plate 3, 4 and at the other end at the frame elements 5. A drive pulley 13 for 1 x 4 support means is provided between the motor 6 and the other end plate 3, 4. The brake disc 15, 16 is arranged at the outside at the end plate 3, 4 at the drive pulley side, wherein the brake disc 15, 16 is movable in axial direction and has a brake lining 30 on either side. In the case of braking, brake springs (not illustrated) press the brake disc 15, 16 against the end plate 3, 4 and generate the braking force. When the brake magnets 23, 25 are acted on by current the brake is released and the brake disc 15, 16 detached from the end plate 3, 4.

A sectional plane running through the centre of the motor 6 at right angles to the shaft 10 is denoted in Fig. 6 by AA. The thus-generated sectional plane of the drive unit 1 is shown in Fig. 7.

Fig. 7 shows a section through the motor 6 and through the frame elements 5. The laminated core 31 of the stator 8 has, at the corners and over the length of the motor 6, round recesses 32 in which tubular frame elements 5 fit. In addition, inner grooves 33, in which flat steels 34 provided with threads fit, are provided parallel to the recesses 32. The tubular frame elements 5 are connected, for example by means of screws 35, with the stator 8, wherein the screws 35 engage in the threads of the flat steels 34 inserted in the grooves 33. As an alternative form of connection the tubular frame elements 5 can be glued in or pressed into the recesses 32 or welded to the laminated core 31. A combination of at least two of the said forms of connection is also possible.

Fig. 8 shows the symmetrical drive unit 1 according to the invention in exploded illustration. Each frame element 5 consists of three parts, wherein the centre part 5.1 is connected with the laminated core 31. The outer parts 5.2, 5.3 serve as spacers between the motor 6 and the respective end plate 3, 4, wherein further screws 36 penetrating the outer parts 5.2, 5.3 connect the end plate 3, 4 with the centre part 5.1. The frame element 5 can also be unitary.