MXPA99006892A - Elevator drive machine - Google Patents

Abstract

The invention relates to an elevator drive machine comprising a traction sheave and an electromechanical apparatus comprising at least two electric motors for driving the traction sheave. The traction sheave and the weight applied to it via the elevator ropes is supported by the bearings between the stators and rotors of the electric motors driving the traction sheave of the drive machine.

Description

ELEVATOR DRIVING MACHINE DESCRIPTION OF THE INVENTION The present invention relates to an elevator drive machine as defined in the preamble of claim 1. The driving machine of a traction sheave elevator comprises a traction sheave with grooves for the lifting or hoisting ropes of the hoist and a lifting pulley. electric motor that drives the traction sheave either directly or by means of a transmission. Traditionally, the electric motor used to drive an elevator has been a direct current motor (D.C.), but more and more alternating current (A.C.) motors are used, such as squirrel-cage motors with electronic control. One of the problems found in gearless lifting machines of conventional construction has been their large size and weight. Such engines require considerable space and are difficult to transport to the site and install. In groups of elevators consisting of large elevators, it has sometimes been necessary to install the elevating or hoisting machines of adjacent elevators on different floors to provide sufficient space for them above the elevator shafts placed side by side. In large lifting machines, torque transmission from the drive motor to the drive pulley can be a problem. For example, large gearless elevators with a conventional drive shaft between the electric motor and the traction sheave are particularly susceptible to developing significant torsional vibrations due to shaft twisting. In recent times, solutions have been presented in which the elevator motor is a synchronous motor, especially a synchronous motor with permanent magnets. For example, specification WO 95/00432 presents a synchronous motor with permanent magnets, which has an axial air gap and in which the traction sheave is connected directly to a disk forming the rotor. Such a solution is advantageous in elevator impellers with a relatively low torque requirement, for example, a lifting or lifting load of approximately 1000 kg, and in which the elevator speed is of the order of 1 m / s. Such a machine provides a special advantage in applications designed to minimize the space needed for the elevator drive machine, for example, in elevator solutions without a machine room. The specification Fl 93340 presents a solution in which the traction sheave is divided into two parts placed on opposite sides of the rotor in the direction of its axis of rotation. Placed on both sides of the rotor are also stator parts formed in the form of a ring-like sector separated from the rotor by air spaces. In the machine presented in specification Fl 95687, the rotor and stator parts on both sides thereof with an air gap therebetween are located within the traction sheave. In this way, the traction sheave is integrated with the rotor, which is provided with magnetizing elements corresponding to each part of the rotor. Specification DE 2115490 A presents a solution designed to drive a rope or coil for rope or the like. This solution uses separate linear motor units that act on the edge of the coil flanges. For elevators designed for loads of several thousand kg and speeds of several meters per second, none of the solutions presented in the specifications mentioned above is capable of developing sufficient torque and rotation speed. Additional problems can be found in the control of axial forces. In engines with multiple air spaces, additional difficulties arise from the divergent electrical and functional properties of the air spaces. This imposes special requirements on the motor's electrical mechanism to allow full-scale use of the motor. Special requirements usually result in a complicated system or a high price, or both.

- A - The specification GB 2116512 A presents a lifting machine with gear which has several relatively small electric motors that drive a single traction sheave. In this way a machine is obtained that needs only a relatively small floor area. The machine presented in GB 2116512 A can be accommodated in the machine room space no greater than the cross-sectional area of the elevator shaft below it. Such an advantageous solution for the machine room has not been usable in the case of large gearless elevators because this typically has a machine with a large motor extending beyond the sides of the traction sheave. Specification EP 565 893 A2 discloses a gearless lifting machine comprising more than one modular motor unit which are connected together to drive the traction sheaves also connected together. In such a solution, the length of the machine increases as its capacity increases when adding an engine module. The problem in this case is that the length of the machine is increased on one side of the traction sheave, which is why the machine extends beyond the width of the elevator shaft in its lower part. A support and rigidification of such a large machine is such that if its own weight and rope suspension do not produce harmful deformations which will probably result in expensive and difficult solutions. For example, bending a large machine requires a special and expensive bearing solution. If the bending or other forms of loading produce even the lightest flattening of the traction sheave to an elliptical shape, this probably leads to vibrations that reduce the comfort in the displacement provided by the lifter. The object of the invention is to obtain a new gearless elevator drive machine which develops a torque, power and rotational speed preferably as needed in large and fast elevators. The invention is characterized by the features presented in claim 1. Other characteristic features of different embodiments of the invention are presented in the other claims. With the solution of the invention, the motor torque is developed by means of two motors or motor blocks, the torque thus being doubled compared to a single motor. The axial forces generated by the two motor blocks compensate each other, and therefore the tension on the bearings and the motor shaft is minimized. With the driving machine of the invention, due to the good torque characteristics of the machine, a large pulley size traction is obtained in relation to the size, operation and weight of the driving machine. For example, an axle load of 40,000 kg can be handled by a machine weighing less than 5,000 kg, even if the elevator speed is as high as 9 m / s or considerably higher. Since the structure of the driving machine allows large rotor and stator diameters in relation to the diameter of the traction sheave, sufficient torque is easily generated on the traction sheave. On the other hand, a short distance between the bearings in the direction of the axis of rotation automatically ensures small radial deflections, so that heavy structures are not needed to avoid such deflections. Especially in the case of elevator driving machines with the highest requirements regarding the load capacity, having a single traction pulley driven by at least two engines helps eliminate relatively high costs in relation to the load capacity of engines large individual By placing the traction sheave between the two motors, a compact machine structure is obtained, as well as a possibility to transmit torque, power and forces directly from the machine to the traction sheave without a separate drive shaft. By coupling the rotors of two different electric motors mechanically together with the traction sheave, these advantages are obtained in a different degree. The very close integration of the rotor parts of the motor with the traction sheave results in a machine in which the rotating parts practically function as a single block, which allows to obtain a better precision in the control of the movements of the elevator . Since the frame of the driving machine is used as much as a vault of the motor / motors as a carrier of the bearings of the moving parts, the total weight, and the space required by the machine are relatively small in comparison with the lifting or hoisting machines conventional designed for corresponding use. In principle, the bearings are only needed for each rotor, whose bearing boxes are easy to seal. Any lubricant that can pass through the seal can be easily guided out in a way that does not cause damage. Because the traction sheave is substantially joined to the joint between the rotor blocks or because the traction sheave is attached to the rotor blocks together along a circle of a very large radius, the torque developed The engine is transmitted directly from the rotor to the traction sheave. In the driving machine of the invention, the air spaces can be adjusted in pairs so that they are of equal size, and the mutual air space sizes of the two-rt motors / motor blocks can even be adjusted in a manner that the motors / motor blocks appear the same for the electrical mechanism. In this way, it is possible to have two motors / motor blocks driven by a single electrical mechanism without differences in the behavior of the motors / motor blocks due to the fact that the driving machine is driven by a single electrical mechanism. Due to its small size and light weight with respect to its load capacity, the machine is easily positioned both with regard to the distribution of the machine room and its installation. Elevating machines with a high load capacity are often used in groups of elevators comprising several elevators. Since the lifting or hoisting machine can be accommodated in a floor area of the machine room with a cross sectional size to that of the elevator shaft below it, this provides a great advantage with respect to the use of space of the building. In the following, the invention will be described with the help of an example, which in itself does not constitute a limitation of the scope of the application of the invention, and by reference to the accompanying drawings, in which: figure 1 presents an elevator driving machine as provided by the invention, seen from the axial direction, figure 2 presents the driving machine of figure 1 in a side view and partially sectioned, figure 3 presents a detail of figure 2 Figure 4 shows a driving machine of Figure 1 in a top view, and Figure 5 illustrates the positioning of the driving machine of the invention. Figure 6 shows a cross-section of another driving machine according to the invention, and Figure 7 shows a detail of Figure 6.

Figure 1 shows a gearless driving machine 1 as provided by the invention, viewed from the axial direction. The figure shows the contour 2a of the traction sheave 2 of the driving machine 1 to illustrate the positioning of the traction sheave in relation to the frame block 3 forming part of the machine frame. The frame block 3 is preferably manufactured by punching or casting, preferably a die-cast iron block. The frame block can also be manufactured, for example, by welding steel sheet parts. However, a welded frame block is probably the only one used in special cases, for example, when a very large machine is to be manufactured as an individual case. Even a frame block as large as approximately 2 m can be advantageously processed by punching if a series of different machines are to be produced. The frame block is stiffened by an alerture 44. The flare is partially annular, and comprises one or more rings, and partially radial. The radial portions of the hedge are directed from the central part of the frame block 3 to the joint points 4, 5, 6, 7 and 8 provided along the edge of each frame block and towards the brake assemblies 10. 9 of the elevator and the legs 11 of the driving machine, whereby the driving machine is fixed to its base. The legs 11 are located near the points of attachment 6, 7 in the lower part of the frame block. The frame block has seats for a fan 2 and a tachometer 13 with the necessary openings. The traction sheave bearings are behind the cover 15. The cover is provided with a duct for the adjustment screw 16 of a device for axial positioning of the traction sheave. The cover 15 is also provided with a filling orifice 42 for the addition of lubricant within the bearing space and an inspection hole or window 41 for inspection of the amount of lubricant. Figure 2 shows the driving machine 1 in a partially sectioned side view. Figure 3 shows a detail of Figure 2, which shows more clearly the arrangement of the bearing. In these figures, the part to the right of the center line of the machine shows the section AA of figure 1, show that the part to the left shows the section RR of figure 1. It is mainly a question of definition if the figure represents a driving machine in which a traction sheave is placed in a motor which has a rotor and a stator divided into blocks, between the two rotor blocks 17, 18 of the motor and attached thereto, or if the figure represents two motors between which a traction sheave 2 is attached to the rotors 17, 18 of the motors. The stators / stator blocks 19, 20 are fixed to the frame blocks 3, 3a. Air spaces are provided between the stators and rotors. The air spaces in the motors shown in the figures are referred to as axial air spaces, in which the flow direction is substantially parallel to the motor axis. Preferably, the winding of the stator is what is called a slot winding. The magnets 21 of the rotor are preferably permanent magnets and are attached to the rotors 17, 18 by a suitable method. The magnetic flux of the rotor passes through the rotor disk 17, 18. Therefore, the part of the rotor disk that lies below the permanent magnets acts as both a part of the magnetic circuit and a structural member of the rotor. The permanent magnets can be of different shapes and can be divided into component magnets placed side by side or one after the other. The rotor disc is preferably manufactured by die cutting of die-cast iron. Both the rotor disk and the frame blocks are preferably shaped so that they are placed together in an identical body, so that it will not be necessary to produce a part and a counterpart separately. The rotor 17, 18 is provided with roller bearings 22 which support the block 3a, 3 of the corresponding frame thereon. The roller bearings 22 support the radial forces. In very large elevators, the bearings must bear a weight of tens of tons, because in many cases almost all the weight of both the elevator car and the counterweight are applied via the elevator ropes to the traction sheave. e Elevator cords and compensating cords or chains also significantly increase the weight. The 10 axial net forces are received by an auxiliary bearing 40. By using an axial adjustment associated with the auxiliary bearing 40, the rotors 17, 18 are joined so that each stator-rotor pair will have an equal air gap. The traction sheave and the rotor blocks join r "15 together to form the rotating part of the machine, supported " - by bearings on the frame blocks. The auxiliary bearing 40, attached to its cage to the rotor, and the screw 16, which makes contact with the bearing shoulder and is supported by the cover 15, acts as an adjustment device in the bearing housing, designed to move the engine blocks in the axial direction. When the screw 16 is rotated, it pushes or pulls the entire rotating part, depending on the direction of rotation. "Since the magnets of the motor in each rotor block tend to pull the rotating part towards the stator corresponding to the rotor In this case, and since the stators and rotors, respectively, are identical, the central position can be found by turning the adjusting screw until the pushing and pulling forces of the screw are practically zero. the central position is when rotating the rotating part and measuring the electromotive force obtained from the stators As the rotating part is rotated, when the electromotive force measured from the first stator block and the measurement from the second stator block are the same, The rotating part has been successfully centered.When it is centered in this way, both stator-rotor pairs have very consistent drive characteristics and they can be driven by a single electric impeller without one of the stator-rotor pairs being subjected to a greater load than the other. The stator 19, 20, together with its winding, is connected by means of fastening elements to the frame block 3 a, 3, which, on the one hand, acts as a mounting that holds the stator in position and, on the other hand, conforms to the vault structure for the entire driving machine. Preferably, the fasteners are screws. The rotor 17, 18 is provided with rotor driving devices mounted opposite the stators. The excitation devices are formed by attaching a series of permanent magnets 23 in succession to the rotor, so as to form a circular ring.

Between the permanent magnets and the stator there is an air gap which is substantially perpendicular to the axis of rotation of the motor. The air space can also be of a somewhat conical shape, in which case the center line of the cone coincides with the axis of rotation. As seen in the direction of the axis of rotation, the traction sheave 2 and the stator 19,20 are placed on opposite sides of the rotor 17,18. Between the blocks 3a, 3 of the frame and the rotors 17,18 there are ring-like cavities in which the stator and the magnets are placed. The outer edges of the rotors 17, 18 are provided with braking surfaces 23, 24 which are engaged by brake pads 25 of the brakes 9. The rotor blocks are provided, with alignment elements by means of which They can place the permanent magnets of the first and second rotors. The permanent magnets are mounted in an arrow pattern. The magnets can be aligned either directly opposite each other or with a slight deviation.

Since the rotors are of identical design, their placement in pairs opposite each other means that although the former rotates forward, the latter, as it is placed, rotates backward in the slot windings in the opposite stators that are mounted in an arrangement from image to mirror. This eliminates any possible structural dependence of the motor operating characteristics in the direction of rotation. The rotor magnets can also be implemented with the arrow figures pointing to the same direction of rotation. The alignment elements are bolts, the number of which is preferably divisible by the number of poles and whose pitch corresponds to the pole pitch or its multiple. Figure 4 shows the driving machine 1 in a top view. The connecting pieces 5b, 8b on the sides of the driving machine which connect the joining points 55a, 8a, 8a of opposite frame blocks are clearly visible, and in this way the connection piece 4b is provided on the upper side of the driving machine which connects to the joining points 4, 4a, in the upper parts of the frame blocks. The upper connecting piece 4b is of a more resistant construction than the other connecting pieces. This upper connection piece 4b is provided with a curl 43 by means of which the drive machine can be hoisted or lifted. In Figure 4, the outline of the wall of the well 39 of the elevator below the driving machine is shown with a dashed line. The driving machine is clearly within this contour. This means saving space in the building. Since the machine is completely contained in the space directly above the elevator shaft, the arrangements of the machine room above the lift bench will be simple. Even when the cross section of the machine room is the same size and shape as the cross section of the elevator shaft, there is sufficient space left free in the machine room around the driving machine to allow all the machines to be carried out. normal service and maintenance operations. By placing the legs 11 near the lower edges of the machine, maximum stability of the machine is obtained when it is mounted and fixed to its support. Preferably, the legs are located substantially outside the planes defined by the stator and rotor blocks. Figure 5 illustrates the manner in which the driving machine 1 is placed in the machine room 45. The driving machine is mounted on a support 46 constructed of steel beams. By using a deflection pulley 47, the distance between the portions of lifting or lifting rope 48 that go towards the lift car and towards the counterweight have been increased in some way from the width corresponding to the diameter of the pulley 2 of traction. The machine in figure 6 is very similar to the one illustrated in figures 1 to 4. For a practical lift, the most important differences are in the way of mounting the traction sheave and in the consequent possibility of using traction sheaves of different widths (lengths?) in the machine that depend more freely on the need defined by each elevator to be installed, and on the manner of implementation of the bearings and the outer end of the rotating shaft. Figure 7 shows a clear illustration of the bearings and the output end of the rotary shaft. In the driving machine in Figure 6, each end of the traction sheave 102 is attached to a rotor 117,118. Therefore, * 4. the traction sheave is placed between two rotors. Jan? In the case of an axial motor as in the present example, the most essential part of the traction sheave, ie the cylinder provided with grooves for the ropes together with the motor magnet ring attached to the traction sheave, remains completely between the two planes defined by the two air spaces perpendicular to the axis of rotation. Even if the internal structure of the motor should differ from the axial motor of the present example, it will be advantageous to place the traction sheave between the parts that generate torque. The rotors 117,118 are rotatably mounted with bearings on the frame blocks 103, 103a in which the stators 119,120 are fixed in place, one in each frame block.The permanent magnets of the rotors are fixed to the rotors 117,118 by a The magnetic flux of the rotor passes through the rotor disc, therefore, the part of the rotor disk that lies below the permanent magnets acts as a part of the magnetic circuit and also as a structural member of the rotor. rotor is supported on the frame blocks by relatively large bearing elements 122. The large bearing size means that the bearing elements 122 can hold radial forces well., for example the roller bearings are of a design that allows the axial movement of the machine. Such bearings are generally cheaper than bearings that prevent axial movement, and also allow the equalization of the air spaces in the stator-rotor pairs on both sides of the traction sheave. The equalization adjustment is performed using a separate, relatively small auxiliary bearing 140 mounted on one of the frame blocks. The auxiliary bearing 140 also receives the axial forces between the traction sheave and the machine frame. The other necessary frame block is not provided with an auxiliary bearing. The auxiliary bearing 140 is fixed to a cover 191 attached to the frame block and covering the bearing space. Mounted on the cover 191 is a spacer 190 or other device for measuring the angle and / or speed, supported by the support 189. The end 188 of the rotating shaft 199 transmits the movement of the traction sheave and projects through the central part 192 of the cover 191, and the spacer shaft is attached to its shaft end. At the other end of the machine shaft, an outlet from the rotating shaft is usually not needed, so that a more simple cover 187 closes the bearing space which is sufficient at that end. On the side facing the traction sheave, the bearing spaces are closed with covers 186. The traction sheave and the rotor parts are joined together to form the rotating part of the machine, supported by the bearings on the blocks of frame. Since the traction sheave is connected to the rotor parts 117,118 by its edge or at least by a locking ring of a large diameter, the rotating part can be considered as constituting the drive shaft of the machine itself. For a practical design, the deflection of such axis is almost nil, so that the design of the bearings of the drive shaft and its suspension in the frame blocks is a very simple task. The auxiliary bearing 140 and the larger bearing 122 bearing the radial forces are placed one after the other in the axial direction, which is a different solution compared to the relative positions of the auxiliary bearing 40 and the larger bearing 22 in the machine illustrated in Figures 1 to 4, in which the auxiliary bearing 40 is located within the larger bearing 22. The successive positioning of the bearings 122 and 140 allows a larger radial space in the bearing 122 that supports the radial load compared to the radial space of the auxiliary bearing 140, because sufficient radial flexibility can be easily obtained in the coupling between the bearings. bearings 122 and 140. Flexibility can be increased by extending auxiliary shaft 199 connecting auxiliary bearing 140 to rotor portion 118 by using a mounting collar 197 to move point 198 of the auxiliary shaft support inwardly in machine. Additional flexibility is obtained by providing the auxiliary shaft 199 with a waist to allow for easier bending of the shaft. In this way, the smaller set of the smaller auxiliary bearing 140 can be used completely. Therefore, the auxiliary bearing makes it possible to obtain a precise adjustment of the axial position. Due to the small radial space, the axis is precisely centered, which has a favorable effect on the correctness of the separator signal. The auxiliary bearing 140 is connected by its cage to the frame of the machine and by its center via the auxiliary shaft 199 to the rotating part formed by the traction sheave and the rotors. By adjusting the mutual positions of the auxiliary shaft and the auxiliary bearing in the axial direction of the machine, it is possible to adjust the positions of the rotors in relation to the frame. The axial adjustment can be implemented, for example, by providing the auxiliary bearing and auxiliary shaft with screw threads that engage with each other. It will be advantageous to adjust the air spaces between the rotors and stators of the driving machine to the same size. On the other hand, the air spaces can be adjusted until both motors / motor blocks appear the same as the electric mechanism. In this way, the two motors / motor blocks can be driven by a single electrical mechanism without incurring differences in motor / motor block behavior because a driving machine is driven by a single electrical mechanism. The establishment of symmetry of the engine / engine blocks through different air spaces can also be affected by the mutual positions of the stators and rotors, especially by the rotation angles between the stators and rotors. Several alternative methods can be used to match the motors of a double motor drive machine. When the motors are matched for operation in the driving machine, the optimization can be carried out by one of the following methods: i) With the free motors, the source voltages are measured and adjusted to the same value when adjusting the spaces of the motor. air and possibly also the stator angles. There are different levels in this: adjust the amplitude of the fundamental wave, its amplitude and phase, additionally the 'harmonics and combinations of these. ii) With no load connected to the motors, the motors are coupled together and the air gap is adjusted and possibly also the angle of the stator packs so that the polyphase current is minimized. Here, it is also possible to consider the fundamental wave and the harmonic wave separately. iii) With a load connected to the motors, the motors are measured and the air spaces are adjusted and possibly also the stator angles until the currents in the two motors are equal. This is an advantageous alternative because any difference in longitudinal impedances can also be taken into consideration. iv) The load is increased to the maximum and the motor currents are then equalized by adjusting the air spaces and possibly also the stator angles. Both engines will now deliver maximum torque and the load capacity of the combination is at a maximum. In methods i) and ii), the measurements are carried out with the motor free, therefore the energy consumption and the temperature increase are also minimized. Items i) - iv) can be combined appropriately, for example, by developing a cost function using appropriate weighting coefficients for compensation of maximum load capacity, energy consumption and harmonics. It is obvious to a person familiar with the art that the embodiments of the invention are not restricted to the example described above, but can be varied within the scope of the following claims.

Claims (10)

1. Gearless elevator drive machine, comprising a traction sheave and an electromechanical apparatus comprising at least two electric motors for driving the rotating part, characterized in that the traction sheave is placed between the two electric motors and wherein the sheave traction and the weight applied to it by means of the elevator ropes is substantially supported, in the radial direction of the driving machine, by the bearings between the stators and rotors of the electric motors that drive the machine's traction sheave driving

2. Driving machine as defined in claim 1, characterized in that the radial forces between the rotating parts and the frame and the axial forces in the driving machine are supported mainly by separate bearing elements.

3. Driving machine as defined in claim 1, characterized in that the traction sheave connects the rotors of the two different electric motors mechanically together.

4. Driving machine as defined in any of the preceding claims, characterized in that the traction sheave is supported without a separate traction sheave shaft.

5. Driving machine as defined in any of claims 1 to 3, characterized in that the traction sheave is a substantially cylindrical body opened therein and having junctions for engines that are mounted coaxially on both sides of the traction sheave.

6. Driving machine as defined in claim 5, characterized in that the junction points for the motors are located at the ends of the traction sheave.

7. Driving machine as defined in claim 6, characterized in that each end of the traction sheave is provided with a flange on which the attachment points of the engine are located.

8. Driving machine as defined in claim 5, characterized in that the traction sheave comprises at least one flange directed to the inside of the traction sheave and which is provided with a point of attachment for a motor driving the traction sheave.

9. Driving machine as defined in any of claims 1 to 3, characterized in that the traction sheave has within it a hollow space whose walls pass the load applied to the driving machine from the traction sheave to the bearings between the stators and rotors of electric motors.

10. Driving machine as defined in claim 9, characterized in that the wall of the hollow space consists substantially only of parts of the traction sheave or the electric motors that drive the traction sheave and where the ends of the hollow space are parts of the motors electric