Patent Application
20190352128
The invention concerns in general the technical field of elevators. The invention concerns especially, however, not exclusively, to controlling of elevator car movement in case of an emergency condition.
In multicar elevator systems, the elevator cars are driven by means of a linear motor. Linear motor has a longitudinal stator rail or beam arranged to extend along the elevator shaft. Each elevator car of the elevator has one or several rotor elements, or movers, coupled to the respective car and arranged in electromagnetic engagement with the stator rail and configured to provide elevator car movement along the stator rail.
The linear motor is controlled to have an air gap between stator and the movers, that is, the movers levitate relative to the stator. The air gap can be established by controlling the active parts of the motor. Active parts may include, for example, motor coils which may be controlled by means of power control of the motor, for example, an electrical drive such as a frequency converter.
In an emergency stop situation, for example, if the operation of the active parts of the linear motor fails for some reason during elevator run, such as if electricity supply to the active parts is unexpectedly interrupted or some of the active parts have failed, the controlling of the levitation by means of the active parts is no longer possible. In these situations, the movers may exhibit lateral movement and become in contact with the stator and/or the stator rail or beam, thus causing high friction and, therefore, excessive deceleration of the elevator car. This problem is severe especially when a car is travelling in upwards direction. The excessive deceleration may be uncomfortable or even harmful for the passengers in the elevator car.
It is known to use guide shoes, such as utilizing rollers or low-friction sliding surfaces, in elevators. Guide shoes are components used to ensure that the elevator car moves along the guide rail and that the lateral movement of the elevator car is minimized. Furthermore, known guide shoes, such as roller or sliding guide shoes, cause friction, noise and include parts which are prone to wearing, and thus increases the amount power needed to move the elevator car along the stator rail as well as require maintenance and/or replacement.
An objective of the present invention is to provide a levitating guide shoe arrangement, a method for guiding an elevator car along a stator beam of an electric linear motor during an emergency condition and an elevator utilizing the levitating guide shoe arrangement and/or the method. Another objective of the present invention is that by utilizing the levitating guide shoe arrangement and/or the method, a mechanical contact between the mover and the stator beam of the electric linear motor can be avoided or at least minimized or made less severe during the emergency condition.
The objectives of the invention are reached by a levitating guide shoe arrangement, a method and an elevator as defined by the respective independent claims.
According to a first aspect, a levitating guide shoe arrangement for guiding an elevator car along a stator beam of an electric linear motor during an emergency condition is provided. The levitating guide shoe arrangement comprises a levitating guide shoe and a guide surface, wherein the guide surface is comprised in the stator beam, and wherein the levitating guide shoe is configured for arranging in an operating position with respect to the guide surface and comprises magnetic field generation means for generating a magnetic field that extends to the guide surface, such as to generate eddy currents therein, wherein the arrangement is configured to establish an air gap between the levitating guide shoe and the guide surface by the magnetic field.
The emergency condition refers especially to conditions in which one or more of the active parts of the electrical linear motor, for example the mover or the stator, are not operable for some reason. Reasons for this may be interruption in the electrical power supply, a broken cable or electrical connection, failure of an electrical drive operating a mover or a stator, or any other reason causing the active parts to stop functioning. In some embodiments, the emergency condition may refer to a predetermined special operating situation, such as an overspeed situation of an elevator car or opening of a safety contact in an elevator safety circuit. The normal operating conditions, on the other hand, refer to conditions in which the elevator serves its landing floors in normal manner.
The guide surface may, preferably, be an electrically conducting surface.
The magnetic field generation means may comprise one or a plurality of electromagnets for generating the magnetic field, preferably as an alternating magnetic field.
The magnetic field generation means may comprise one or a plurality of permanent magnets for generating the magnetic field.
The magnetic field generation means may comprise a plurality of permanent magnets arranged in a Halbach array.
The levitating guide shoe may be configured to be coupled to a mover of the electric linear motor or to the elevator car, wherein the arrangement may be configured to establish an air gap between the mover and the stator beam.
The levitating guide shoe may comprise an actuator for changing a position of the magnetic field generation means relative to the guide surface.
According to a second aspect, a method for guiding an elevator car along a stator beam of an electric linear motor during an emergency condition is provided. The method comprises
The magnetic field generation means may comprise one or a plurality of electromagnets, in which case in the method the generation of the magnetic field may comprise generating a magnetic field, preferably an alternating magnetic field, by the one or the plurality of electromagnets to engage with or to extend into the guide surface.
The levitating guide shoe may comprise one or a plurality of permanent magnets, in which case in the method the generation of the magnetic field may comprise generating a magnetic field by the one or the plurality of permanent magnets to engage with or to extend into the guide surface.
In the method, the levitating guide shoe may comprise a plurality of permanent magnets arranged in a Halbach array.
The arranging of the levitation guide shoe may be performed after the detection of the emergency condition by moving the levitating guide shoe into the operating position by an actuator.
Alternatively, the arranging of the levitation guide shoe may be performed prior to the detection of the emergency condition, and the generation of the magnetic field may then be performed after the detection of the emergency condition.
According to a third aspect, an elevator for guiding an elevator car along a stator beam of an electric linear motor during an emergency condition is provided. The elevator comprises an arrangement according to the first aspect.
In the elevator, the guide surface comprised in the stator beam may be common to the levitating guide shoes of the plurality of said arrangements according to the first aspect.
The present invention provides a levitating guide shoe arrangement, a method for guiding an elevator car along a stator beam of an electric linear motor during an emergency condition and an elevator. The present invention provides an advantage over known solutions such that in emergency conditions, particularly in ones in which the active parts of the electric linear motor of the elevator are disabled or unusable, a contact between the motor parts can be avoided or at least made severe which further decreases the deceleration of the elevator car in the emergency condition. High deceleration of the elevator car may become even harmful for the passengers inside the elevator car.
Various other advantages will become clear to a skilled person based on the following detailed description.
The expression “a plurality of” refers herein to any positive integer starting from two, e.g. to two, three, or four.
The terms “first”, “second” and “third” do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.
The exemplary embodiments of the present invention presented herein are not to be interpreted to pose limitations to the applicability of the appended claims. The verb “to comprise” is used herein as an open limitation that does not exclude the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated.
The novel features which are considered as characteristic of the present invention are set forth in particular in the appended claims. The present invention itself, however, both as to its construction and its method of operation, together with additional objectives and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
The embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.
The electrical drive 12 may be utilized for operating a mover or movers (not shown in
There are preferably at least two landing floors, having landing floor doors 19 or opening 19, comprised in the elevator 100. There may preferably also be doors comprised in the elevator car 10. Although shown in
Regarding the elevator shaft 13, it may be such as defining substantially closed volume in which the elevator car 10 is adapted and configured to be moved. The walls may be, for example, of concrete, metal or at least partly of glass, or any combination thereof. The elevator shaft 13 herein refers basically to any structure or pathway along which the elevator car 10 is configured to be moved and into which the stator beam 22 of the electric linear motor of the elevator may be arranged.
As can be seen in
The elevator 100 may comprise an elevator control unit 1000 for controlling the operation of the elevator 100. The elevator control unit 1000 may be a separate device or may be comprised in the other components of the elevator 100 such as in or as a part of the electrical drive 12. The elevator control unit 1000 may also be implemented in a distributed manner so that, e.g., one portion of the elevator control unit 1000 may be comprised in the electrical drive 12 and another portion in the elevator car 10. The elevator control unit 1000 may also be arranged in distributed manner at more than two locations or in more than two devices.
The elevator control unit 1000 may comprise one or more processors, one or more memories being volatile or non-volatile for storing portions of computer program code and any data values and possibly one or more user interface units. The mentioned elements may be communicatively coupled to each other with e.g. an internal bus.
The processor of the elevator control unit 1000 is at least configured to implement at least some method steps as described hereinafter. The implementation of the method may be achieved by arranging the processor to execute at least some portion of computer program code stored in the memory causing the processor, and thus the elevator control unit 1000, to implement one or more method steps as described. The processor is thus arranged to access the memory and retrieve and store any information therefrom and thereto. For sake of clarity, the processor herein refers to any unit suitable for processing information and control the operation of the elevator control unit 1000, among other tasks. The operations may also be implemented with a microcontroller solution with embedded software. Similarly, the memory is not limited to a certain type of memory only, but any memory type suitable for storing the described pieces of information may be applied in the context of the present invention.
Part of the levitating guide shoe arrangement 20 according to various embodiments may be coupled to the elevator car 10 or to the mover 21. The levitating guide shoe arrangement 20 may comprise a levitating guide shoe 23 and a guide surface 35 comprised in the stator beam 22. The levitating guide shoe 23 may, preferably, be arranged to be close to the guide surface it its operating position so as to enable establishing a magnetic engagement between the levitating guide shoe 23 and the guide surface 35 by magnetic field generating means such as an electromagnet or a permanent magnet. The levitating guide shoe arrangement 20 may be controlled by the elevator control unit 1000, that is, being at least communicatively coupled to the elevator control unit 1000.
The movement of the mover 21 along the stator beam 22 may be implemented by known control methods, such as, field-oriented or vector control or the like. The basic idea is to produce an alternating magnetic field, for example by an electrical drive 12, by injecting current to a unit of electromagnetic components 32 of the mover 21, such as to a winding or coil thereof. The unit of electromagnetic components 32 facing the stator 15 then co-acts with the stator 15 through the electromagnetic engagement and produces a force which moves the mover 21 and thus the elevator car 10 along the stator beam 22.
Furthermore,
According to an embodiment of the present invention, the magnetic field generation means 40 of the levitating guide shoe 23 may comprise, alternatively or in addition, one or a plurality of permanent magnets. Thus, the magnetic field 45 may be constant or at least comprise a constant portion generated by the permanent magnet(s) in addition to the field 45 generated by the electromagnet.
According to an embodiment of the present invention, the levitating guide shoe 23, for example being coupled to the elevator car 10, of the arrangement 20 may be arranged to a second position 602. Only after an emergency condition is detected, the levitating guide shoe 23 or shoes 23 are being changed into its or their operating positions 601 after which the magnetic field 45 may be used to establish or maintain the air gap 41 between the levitating guide shoe 23 and the respective guide surface 35. If the levitating guide shoe 23 is coupled to the elevator car 10, for instance, by establishing the air gap 41, the arrangement 20 may further be arranged such as to simultaneously establish a gap (that is, an air gap 30) between the mover 21 and the stator beam 22.
According to another embodiment of the present invention, if the levitating guide shoe 23 comprises an electromagnet comprising a coil 40A, there may no need to arrange the levitating guide shoe 23 or shoes 23 into any other position than the operating position 601. In such a case, the electromagnet may be kept inactive, that is not injecting current into the coil 40A, during normal operating conditions of the elevator 100 and only activated once an emergency condition has been detected. According to still another embodiment, if the levitating guide shoe 23 comprises a permanent magnet 40B or magnets 40B (such as in Halbach array), it may be especially advantageous to arranged the levitating guide shoe 23 or shoes 23 into its or their second positions 602 during the normal operation conditions of the elevator 100 and then to its or their operating positions 601 once an emergency condition has been detected in order to avoid generating eddy currents during the normal operation conditions of the elevator 100.
Step 71 refers to detecting an emergency condition of the elevator 100. Herein the emergency condition refers especially to conditions in which the active parts of the electrical linear motor 16, for example the mover 16 or the stator 15, are not operable for some reason. Reasons for this may be interruption in the electrical power supply, a broken cable or electrical connection, failure of an electrical drive 12 operating a mover 16 or a stator 15, or any other reason causing the active parts to stop functioning. The detection 71 may relate to detecting a safety circuit related event. The detection 71 may be performed by the elevator control unit 1000 or a separate control unit comprising at least a processor.
Step 72 refers to arranging a levitating guide shoe 23 into an operating position 601 with respect to a guide surface 35 comprised in the stator beam 22. This may entail arranging it to the operating position 601 during the normal operation conditions of the elevator 100, for example, even before starting the normal operation conditions of the elevator 100, such as when the levitating guide shoe 23 comprises only electromagnets. On the other hand, the arranging 72 may be performed only after the detection 71 of the emergency condition, such as in case of utilizing permanent magnets in the levitating guide shoe 23. The arranging 72 may, according to some embodiment, be performed by an actuator 60.
Step 73 refers generating a magnetic field 45 by magnetic field generation means 40 comprised in the levitating guide shoe 23 for establishing an air gap 41 between the levitating shoe 23 and the guide surface 35. As stated hereinearlier, this may be performed by an electromagnet or electromagnets, a permanent magnet 40B or magnets 40B, such as arranged in Halbach array, or any combination thereof. The magnetic field 45 cause eddy currents in the guide surface 35 thus causing a force between the levitating guide shoe 23 and the guide surface 35 establishing an air gap 41 between the two. Furthermore, if the levitation guide shoe 23 has been coupled to the elevator car 10 or the mover 16 thereof, the magnetic field 45 may be simultaneously utilized to establish a gap between the mover 21 and the stator beam 22.
In case some movers or at least part of a mover is still in working order during the emergency stop, the operable mover(s) may be utilized in addition to provide propulsion force to reduce elevator car deceleration further to an acceptable level.
Method execution is stopped at step 79. Operation the elevator 100 may be continued in the normal operation conditions or in the emergency conditions.
Furthermore, the method may be performed continuously or intermittently, if necessary.
The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18172359.4 | May 2018 | EP | regional |
