HK1219086B - Linear motor stator core for self-propelled elevator - Google Patents

Description

Linear motor stator core for self-propelled elevators

Field of the Invention

The subject matter disclosed herein relates generally to the field of elevators, and more particularly, to linear motor stator cores for self-propelled elevators.

background

Self-propelled elevator systems, also known as ropeless elevator systems, are useful in certain applications (e.g., high-rise buildings) where the mass of the rope used to lash the system is too high and/or where multiple elevator cars are required in a single hoistway.

Overview

According to an exemplary embodiment, an elevator system includes a hoistway; an elevator car traveling in the hoistway; a permanent magnet mounted to one of the elevator car and the hoistway; and a stator mounted to the other of the elevator car and the hoistway, the stator including windings that cooperate with the permanent magnets to control movement of the elevator car in the hoistway, the stator having a stator core that supports the windings, the stator core being non-conductive.

According to another exemplary embodiment, a propulsion system for an elevator system includes a fixed portion configured to be fixed to a hoistway wall; and a moving portion configured to be fixed to an elevator car; wherein one of the fixed portion and the moving portion includes a permanent magnet, and the other of the fixed portion and the moving portion includes a winding; and wherein the permanent magnet and the winding are configured to act together to control movement of the moving portion relative to the fixed portion.

Other aspects, features, and techniques of embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying drawings, wherein like elements are numbered the same throughout the drawings:

FIG1 depicts a self-propelled elevator system in an exemplary embodiment;

FIG2 depicts a permanent magnet in an exemplary embodiment;

3 and 4 depict the stator and permanent magnets in an exemplary embodiment;

5 and 6 depict a stator and permanent magnets in another exemplary embodiment; and

7 and 8 depict a stator and permanent magnets in another exemplary embodiment.

Details

FIG1 depicts an elevator system 10 having a self-propelled elevator car 12 in an exemplary embodiment. Elevator system 10 includes an elevator car 12 that travels in a hoistway 14. Elevator car 12 is guided by one or more guide rails 16 extending along the length of hoistway 14. Elevator system 10 employs a linear motor having a stator 18 that includes multiple phase windings. Stator 18 can be mounted to, incorporated into, or positioned remote from guide rails 16. Stator 18 serves as one part of a permanent magnet synchronous linear motor to transmit motion to elevator car 12. Permanent magnets 19 are mounted to car 12 to provide the second part of the permanent magnet synchronous linear motor. The windings of stator 18 can be arranged in three phases, as is known in the electric motor art. Two stators 18 can be positioned in hoistway 14 to cooperate with permanent magnets 19 mounted to elevator car 12. Permanent magnets 19 can be positioned on either side of elevator car 12, as shown in FIG1 . Alternative embodiments may use a single stator 18 - permanent magnet 19 configuration, or multiple stator 18 - permanent magnet 19 configurations.

The controller 20 provides drive signals to the one or more stators 18 to control the movement of the elevator car 12. The controller 20 can be implemented using a general-purpose microprocessor that executes a computer program stored on a storage medium to perform the operations described herein. Alternatively, the controller 20 can be implemented in hardware (e.g., an ASIC, an FPGA) or a combination of hardware/software. The controller 20 can also be part of an elevator control system. The controller 20 can include power circuitry (e.g., an inverter or a driver) to power the one or more stators 18.

FIG2 depicts the permanent magnet 19 in an exemplary embodiment. The permanent magnet 19 is mounted to a permanent magnet support 30. Various exemplary permanent magnet supports are described herein with reference to FIG3 through FIG8. FIG2 depicts the orientation of the magnetic poles of the permanent magnet 19. As shown in FIG2, the magnetic poles alternate north, south, north, south, and so on, along the direction of travel of the car 12.

3 is a perspective view of the stator 100 and the permanent magnet support 200 in an exemplary embodiment. The stator 100 includes a plurality of windings 102 formed around a stator core 104. The windings 102 can be arranged into a plurality of phases (e.g., three phases, six phases, nine phases, two phases, etc. as shown). Electrical conductors (e.g., wires, tapes) such as copper or aluminum can be used to form the windings 102. Using aluminum (e.g., wires or tapes) for the windings 102 reduces the mass of the stator 102 and reduces installation costs. The stator 100 is mounted to a stator support 106, which can be a metal member fixed to the inner wall of the well 14. The stator support 106 can also serve as a guide rail 16.

The stator core 104 is non-conductive. In an exemplary embodiment, the stator core 104 can be constructed from a non-conductive member having a desired shape. For example, a plastic, hollow member can be used for the stator core 104. The at least partially hollow stator core 104 can be used to route wires, cables, etc. through the hoistway 14. The plastic member can be filled with a curable material (e.g., concrete) to improve its strength. Other embodiments described herein include a non-conductive ferromagnetic stator core.

FIG4 depicts a permanent magnet support 200 having permanent magnets 19 positioned around the stator 100. One or more permanent magnet supports 200 may be mounted to the elevator car 12. The permanent magnet supports 200 may be made of a ferromagnetic material (e.g., steel). To reduce weight, the permanent magnet supports 200 may be made of aluminum (or a different lightweight material). In such an embodiment, the permanent magnets 19 may be arranged in a configuration other than that shown in FIG2 (e.g., a Halbach array pattern).

The permanent magnet support 200 is arranged in a triangular shape and has a first wall 202, a second wall 204, and a third wall 206. The permanent magnet 19 is mounted on the inner surfaces of the first wall 202, the second wall 204, and the third wall 206. In an alternative embodiment, the permanent magnet 19 is embedded in the permanent magnet support 200. The permanent magnet 19 is positioned adjacent to and parallel to the face of the stator 100. The second wall 204 and the third wall 206 each have a first end that joins the first wall 202. The second wall 204 and the third wall 206 gradually taper toward each other as they move away from the first wall 202. The second wall 204 and the third wall 206 each have a distal second end such that the distance between the second end of the second wall 204 and the third wall 206 is less than the distance between the first end of the second wall 204 and the third wall 206. The second wall 204 and the third wall 206 can be planar or non-planar (e.g., having a curve, as shown in FIG. 4 ).

5 is a perspective view of the stator 110 and the permanent magnet support 210 in an exemplary embodiment. The stator 110 includes a plurality of windings 112 formed around a stator core 114. The windings 112 can be arranged into multiple phases (e.g., three phases). Electrical conductors (e.g., wires, tapes) such as copper or aluminum can be used to form the windings 112. Using aluminum (e.g., wires or tapes) for the windings 112 reduces the mass of the stator 112 and reduces installation costs. The stator 110 is mounted to a stator support 116, which can be a metal member fixed to the inner wall of the well 14. The stator support 116 can also serve as a guide rail 16.

The stator core 114 is non-conductive. In an exemplary embodiment, the stator core 114 can be formed from a non-conductive member having a desired shape. For example, a plastic, hollow member can be used for the stator core 114. The at least partially hollow stator core 114 can be used to route wires, cables, etc. through the hoistway 14. The plastic member can be filled with a curable material (e.g., concrete) to improve its strength. Other embodiments described herein include a non-conductive ferromagnetic stator core.

FIG6 depicts a permanent magnet support 210 having permanent magnets 19 positioned around the stator 110. One or more permanent magnet supports 210 may be mounted to the elevator car 12. The permanent magnet supports 210 may be made of a ferromagnetic material (e.g., steel). To reduce weight, the permanent magnet supports 210 may be made of aluminum (or a different lightweight material). In such an embodiment, the permanent magnets 19 may be arranged in a configuration other than that shown in FIG2 (e.g., a Halbach array pattern).

The permanent magnet support 210 is arranged in a U-shape, having a first wall 212, a second wall 214, and a third wall 216. The permanent magnet 19 is mounted on the inner surfaces of the first wall 212, the second wall 214, and the third wall 216. In an alternative embodiment, the permanent magnet 19 is embedded in the permanent magnet support 210. The permanent magnet 19 is positioned adjacent to and parallel to the face of the stator 110. The second wall 214 and the third wall 216 each have a first end that engages the first wall 212. The second wall 214 and the third wall 216 are perpendicular to the first wall 212. The first wall 212 is longer than both the second wall 214 and the third wall 216.

7 is a perspective view of the stator 120 and the permanent magnet support 220 in an exemplary embodiment. The stator 120 includes a plurality of windings 122 formed around a stator core 124. The windings 122 can be arranged into multiple phases (e.g., three phases). Electrical conductors (e.g., wires, tapes) such as copper or aluminum can be used to form the windings 122. Using aluminum (e.g., wires or tapes) for the windings 122 reduces the mass of the stator 122 and reduces installation costs. The stator 120 is mounted to a stator support 126, which can be a metal member fixed to the inner wall of the well 14. The stator support 126 can also serve as a guide rail 16.

The stator core 124 is non-conductive. In an exemplary embodiment, the stator core 124 can be constructed from a non-conductive member having a desired shape. For example, a plastic, hollow member can be used for the stator core 124. The at least partially hollow stator core 124 can be used to route wires, cables, etc. through the hoistway 14. The plastic member can be filled with a curable material (e.g., concrete) to improve its strength. Other embodiments described herein include a non-conductive ferromagnetic stator core.

FIG8 depicts a permanent magnet support 220 having permanent magnets 19 positioned around the stator 120. One or more permanent magnet supports 220 may be mounted to the elevator car 12. The permanent magnet supports 220 may be made of a ferromagnetic material (e.g., steel). To reduce weight, the permanent magnet supports 220 may be made of aluminum (or a different lightweight material). In such an embodiment, the permanent magnets 19 may be arranged in a configuration other than that shown in FIG2 (e.g., a Halbach array pattern).

The permanent magnet support 220 is arranged in a double I-shape, having a first wall 222, a second wall 224, and a third wall 226. The permanent magnets 19 are mounted on the inner surfaces of the second wall 224 and the third wall 226. In an alternative embodiment, the permanent magnets 19 are embedded in the permanent magnet support 220. The permanent magnets 19 are positioned adjacent to and parallel to the face of the stator 120. The second wall 224 and the third wall 226 each have a first end that engages the first wall 222. The second wall 224 and the third wall 226 are perpendicular to the first wall 222. The first wall 22 is shorter than both the second wall 224 and the third wall 226.

In the embodiment described above, the stator is fixed and mounted in the hoistway 14, while the permanent magnets are mounted to the elevator car 12. Linear motors can also be designed with the stator mounted to the elevator car 12, and the permanent magnets mounted along the hoistway 14.

FIG1 depicts stators 18 and permanent magnets 19 on two sides of the car 12. In an exemplary embodiment, the permanent magnets 19 are located on the sides of the car 12 along an axis that projects through the center of gravity of the car 12. Positioning the permanent magnets 19 in this manner reduces lateral forces acting on the car 12 that can cause severe vibration and mechanical instability. In other embodiments, the permanent magnets 19 are mounted to a single side or corner of the car 12. In such an embodiment, an actively controlled guidance system can be used to compensate for torsional forces on the car 12.

Notably, the stator cores 104, 114, and 124 are toothless, meaning that the stators do not rely on magnetic poles or other extensions having windings formed thereon. Instead, the stator cores 104, 114, and 124 have a continuous, planar surface. The toothless construction provides a low dependency of the motor's dimensional performance on the non-magnetic gap (i.e., the mechanical air gap between the stationary stator and the moving permanent magnets mounted on the elevator car). This allows the linear motor to be designed with a comfortable gap between the long stationary stator and the permanent magnets mounted to the moving car. Furthermore, the toothless construction of the stator eliminates any cogging forces present in typical linear motor structures. Cogging forces in modulated linear motors are a common source of vibration and noise in elevator systems.

Other embodiments utilize a stator core that is non-conductive and ferromagnetic. Utilizing a stator core of non-conductive, ferromagnetic material provides a linear motor with reduced size along the shaft. In one embodiment, the stator core is made of a sintered soft magnetic composition of ferromagnetic powder (e.g., Somaloy™). In another embodiment, the stator core is made of a mixture of a curable material (e.g., a resin) and a soft ferromagnetic powder. In another embodiment, the stator core is made of a mixture of a curable material (e.g., a polymer and/or concrete) and a ferromagnetic material (e.g., ferromagnetic powder and/or ferromagnetic metal). In another embodiment, the stator core is made of laminated steel sheets.

Embodiments of the present invention provide numerous benefits. The embodiments described herein provide a linear motor with reduced size when compared to other possible solutions. The smaller size provides for lower mass of electromagnetically active material, controlled costs, and space utilization in the shaft. Manufacturing the stator core is simplified. Large elements of the stator core can be manufactured: (1) using a sintering process (2) by injection molding of a mixed ferromagnetic material with epoxy resin or (3) by local sealing of the stator modules with a mixed plastic/concrete/ferromagnetic powder. The use of a non-conductive, ferromagnetic stator core increases the magnetic field in the air gap of the motor, which results in a reduction in excitation current and lower conduction losses. In addition, the non-conductive, ferromagnetic stator core eliminates eddy currents in the stator core, which further reduces power losses and heat generated in the stator core when compared to a laminated steel core.

The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Although a description of the present invention has been given for the purpose of illustration and description, it is not intended to be exhaustive or to be limited to the invention of the disclosed form. Without departing from the scope and spirit of the present invention, those skilled in the art will understand that many modifications, variations, changes, substitutions or equivalent arrangements not described herein are provided. In addition, although various embodiments of the present invention have been described, it should be understood that aspects of the present invention may only include some of the described embodiments. Therefore, the present invention should not be considered to be limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims (14)

1. An elevator system comprising: Well; an elevator car traveling in the hoistway; a permanent magnet mounted to one of the elevator car and the hoistway; and a stator mounted to the other of the elevator car and the hoistway, the stator including windings that cooperate with the permanent magnets to control movement of the elevator car in the hoistway, the stator having a stator core supporting the windings, the stator core being non-conductive and the windings being formed around the stator core, wherein the stator core comprises ferromagnetic material and is made of a sintered magnetic composition of ferromagnetic powder, a mixture of a solidifiable material and ferromagnetic powder, or a mixture of a solidifiable material and a ferromagnetic metal. 2. The elevator system of claim 1, wherein: The permanent magnet is supported on a permanent magnet support. 3. The elevator system of claim 2, wherein: The permanent magnet is mounted on an inner surface of the permanent magnet support. 4. The elevator system of claim 2, wherein: The permanent magnet is embedded in the permanent magnet support. 5. The elevator system of claim 2, wherein: The permanent magnet support has a first wall, a second wall, and a third wall, the second wall and the third wall being joined to the first wall, the second wall and the third wall being tapered toward each other. 6. The elevator system of claim 2, wherein: The permanent magnet support has a first wall, a second wall, and a third wall, the second wall and the third wall being joined to the first wall, and the second wall and the third wall being perpendicular to the first wall. 7. The elevator system of claim 1, wherein: The permanent magnets are positioned adjacent to and parallel to the outer surface of the winding. 8. The elevator system of claim 1, wherein: The stator core is at least partially hollow. 9. The elevator system of claim 1, wherein: The stator core includes a solidified material. 10. The elevator system of claim 9, wherein: The solidifying material is concrete. 11. The elevator system of claim 1 , wherein: The stator core is toothless. 12. A propulsion system for an elevator system, the propulsion system comprising: a fixing portion configured to be fixed to a hoistway wall; and a moving portion configured to be secured to the elevator car; wherein one of the fixed portion and the moving portion includes a permanent magnet and the other of the fixed portion and the moving portion includes a winding; wherein the permanent magnets and the windings are configured to act together to control movement of the moving portion relative to the fixed portion; and The winding of one of the fixed part and the movable part comprises a winding formed around a non-conductive inner core, and wherein the non-conductive inner core comprises a ferromagnetic material and is made of a sintered magnetic composition of ferromagnetic powder, a mixture of a solidifiable material and ferromagnetic powder, or a mixture of a solidifiable material and a ferromagnetic metal. 13. The propulsion system of claim 12, wherein the non-conductive inner core has a trapezoidal cross-section. 14. The propulsion system of claim 12, wherein the non-conductive inner core includes a plurality of channels configured to receive electrical cables.