ELEVATOR MACHINE ASSEMBLY

INCLUDING A FLEXIBLE DISK COUPLING FOR A MOTOR

AND TRACTION SHEAVE

BACKGROUND

[0001] Elevator systems include an elevator car that moves vertically to carry passengers, cargo or both to various levels within a building or structure. There are different arrangements for propelling the elevator car and supporting it within a hoistway.

[0002] In traction-based elevator systems, an elevator machine assembly includes a motor, a drive for controlling operation of the motor and a traction sheave that is driven by the motor to cause desired movement of the elevator car. A load bearing assembly (e.g., round ropes or flat belts) supports the weight of the elevator car and follows the traction sheave such that movement of the traction sheave causes corresponding movement of the elevator car. The drive provides power to the motor and includes electronics for providing motor control signals for operating the motor to achieve desired elevator motion. The drive typically operates in communication with an elevator controller that makes determinations regarding required elevator car movement to serve passengers based upon outstanding hall calls or entered desired destinations, for example.

[0003] In most systems, the traction sheave includes a shaft that extends into the motor and forms part of the rotor of the motor. In many instances, the traction sheave shaft supports magnets of the electric motor. One drawback to such an arrangement is that vibrations associated with motor operation are experienced by the traction sheave and that impacts an amount of vibration and noise that affects a perceived quality of elevator system operation. Another drawback associated with such arrangements is that any maintenance or replacement of the traction sheave or the motor necessarily involves the other. Typically, an entire traction sheave shaft and motor must be replaced together even if only one of those components is a cause for the replacement. This has a tendency to introduce additional expenses over the life of an elevator system. It also makes maintenance or repairs on site more complicated, expensive or both.

SUMMARY

[0004] An exemplary elevator machine assembly includes a motor, a traction sheave and a coupling that couples the motor to the traction sheave. The coupling includes at least one disk that is at least partially flexible. [0005] The various features and advantages of disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 schematically illustrates an example elevator machine assembly.

[0007] Figure 2 is an elevational view of selected portions of an example elevator machine assembly. [0008] Figure 3 is a perspective illustration of a portion of an example coupling.

[0009] Figure 4 is a perspective illustration of another example portion of an example coupling.

[00010] Figure 5 is a cross-sectional illustration of selected portions of an example elevator machine assembly.

DETAILED DESCRIPTION

[00011] Figure 1 schematically shows an elevator machine assembly 20. A motor 22 is associated with a traction sheave 24 to cause desired rotation of the traction sheave 24 to achieve a desired elevator car movement. A brake portion 26 prevents rotation, slows down or stops movement of the traction sheave 24 to maintain a desired position or speed of an associated elevator cab, for example. The example elevator machine assembly 20 includes a machine frame 30 including support plates 32 and support rods 36. [00012] Referring to Figures 2-5, one illustrated example includes a coupling

40 that couples the motor 22 to the traction sheave 24 such that the motor 22 can caus the traction sheave 24 to rotate. The illustrated coupling 40 includes a generally cylindrical shaft having a body 42. One end 48 of the body 42 is coupled with the traction sheave 24. In the example of Figure 5, the end 48 is received at least partially

within a bore 50 in the shaft of the traction sheave 24. A securing member 52, such as a bolt is received through a bore 54 in the body 52 and into a corresponding bore 56 in the shaft of the traction sheave 24. In this example, a frictional taper and key connection secures the body 42 of the coupling 40 to the shaft of the traction sheave 24 such that the body 42 and the traction sheave 24 rotate together.

[00013] An opposite end 58 of the body 42 is coupled with a portion of the motor 22. In the illustrated example, a flange 60 is received against at least one disk 62. The illustrated example includes a plurality of disks 62. A securing member 64 is received against an opposite side of the disks 62. In one example, the securing member 64 comprises a ring. A plurality of fasteners 66 secures the flange 60, securing member 64 and disks 62 together so that they rotate in unison.

[00014] The disks 62 are secured to a rotating portion of the motor 22. In the example of Figure 5, fasteners 68 secure a radially outward edge of the disks 62 to a rotor 70 of the motor 22. A central portion 72 of the rotor 70 is supported for rotation about a bearing 74, which is supported on a housing 76 of the motor 22. The housing 76 is secured to one of the support plates 32 of the machine frame 30. As the rotor 70 rotates relative to the stator 78 and the motor housing 76, the connection between the rotor 70 and the disks 62 causes rotation of the coupling 40 and rotation of the traction sheave 24. [00015] One feature of the illustrated example is that the coupling 40 allows for independently mounting the traction sheave 24 and the motor 22 in desired positions as part of the machine assembly 20 such that the motor 22 and the traction sheave 24 can independently maintain concentricity and alignment with corresponding portions of the mounting structure while still transferring the necessary torque between the motor 22 and the traction sheave 24 to achieve a desired elevator system operation. This type of arrangement is different than traditional elevator machine arrangements where the shaft of the traction sheave extends into the motor housing and the permanent magnets of the motor are typically mounted to that shaft. As can be appreciated from the drawings, with the illustrated example, the shaft of the traction sheave does not extend into the rotor of the motor. Instead, the coupling 40 provides an interface between the motor 22 and the traction sheave 24.

[00016] In the illustrated example, the traction sheave 24 is supported by a bearing 80 that facilitates rotation of the traction sheave 24 relative to the corresponding support plate 32 of the frame 30. The motor housing 76 and the

bearing 74 facilitate the support and rotation of the motor rotor 70 relative to the support plate 32. The coupling 40 provides for transmitting torque from the motor 22 to the traction sheave 24 while allowing for the independent concentric position and alignment of the traction sheave 24 and the motor 22 relative to their respective portions of the supporting structure.

[00017] One feature of the illustrated example is that the disks 62 are at least somewhat flexible in an axial direction (e.g., along an axis of the coupling body 42 and the traction sheave shaft 24, which is from right to left according to Figure 2 and Figure 5, for example). Providing some flexibility accommodates any misalignment between the motor 22 and the traction sheave 24. The disk 22 is otherwise rigid such that it transmits torque from the motor 22 through the coupling 40 to the traction sheave 24.

[00018] One example includes a single disk 62. Another example includes a plurality of disks that are all coupled to the end 58 of the coupling 40. In one example, a plurality of disks 62 are received between the flange 60 and the securing member 64 as schematically shown in Figure 5, for example. In one example, at least one disk 62 comprises a high strength, low alloy steel. Examples of such a material include EX-10 50 ASTM A-607 and Corten Type 4 ASTMA-606.

[00019] One feature of the example coupling 40 is that it allows for not supporting the motor 22 in a cantilevered fashion on the shaft of the traction sheave 24. With the prior arrangements mentioned above, the motor was effectively cantilevered on shaft of the traction sheave 24. Including the example coupling 40 and the bearing 74, for example, allows for decoupling motor vibrations from the rest of the system and provides better support for the loads. Additionally, this feature reduces noise transmissions that may otherwise be associated with motor operation and vibrations.

[00020] The example coupling 40 renders the machine assembly modular in the sense that the traction sheave 24, coupling 40, motor 22 or a combination of them may be independently replaced or changed with a different corresponding component. This feature enhances efficiencies associated with assembly, maintenance or repair of the machine components. For example, as the traction sheave shaft no longer extends into the motor where it was part of the rotor, it is now possible to replace the motor or the traction sheave independent of the other.

[00021] Another feature of the illustrated example is that the coupling 40 provides an output that is indicative of torque exhibited at the traction sheave 24. The example coupling 40 includes a magnetoelastic material that generates a magnetic field that is indicative of torque experienced by the coupling 40. In the example of Figure 3, the body 42 of the coupling shaft comprises a magnetoelastic material that is infused into the body 42. In other words, in the example of Figure 3, the material used for making the body 42 comprises a magnetoelastic material.

[00022] In the example of Figure 4, a layer of magnetoelastic material is provided on an exterior of the body 42 of the coupling 40. In the illustrated example, the layer of magnetoelastic material comprises a ring or a sleeve 90 on the exterior of the body 42.

[00023] Magnetoelastic materials are known and the way in which they generate a magnetic field responsive to torque applied to a rod, for example, is known. [00024] The illustrated example utilizes the magnetic field-generating property of the magnetoelastic material to provide an indication of torque at the traction sheave 24.

[00025] As can be appreciated from Figures 2 and 5, the body 42 of the coupling 40 has an outside diameter d that is smaller than an outside diameter D of the shaft of the traction sheave 24. The smaller diameter d results in higher torque at that location. The smaller diameter d of the body 42 experiences a higher amount of stress compared to a larger shaft such as the shaft having the diameter D of the traction sheave 24. The higher amount of stress causes a resulting higher magnetic field output from the magnetoelastic material. This can provide an enhanced ability to detect torque based on the magnetic field provided by the magnetoelastic material. The smaller diameter d allows for the magnetoelastic material to provide a torque- indicating output of sufficient amplitude to allow for determining the torque applied by the motor 22.

[00026] The example of Figure 5 includes a plurality of sensors 92 supported by a sensor plate 94 such that the sensors 92 detect the magnetic field output by the magnetoelastic material of the coupling 40. In one example, the sensors 92 comprise Hall sensors. Other magnetic sensing technologies are used in other examples.

[00027] The example sensors 92 are shielded from the magnetic field of the motor 22 by the flexible discs 62 in the illustrated example. In another example, the

sensors 92 are contained within a housing that shields them from magnetic fields that would interfere with an ability to detect the magnetic field of the coupling 40 to provide an indication of torque exhibited at the traction sheave 24. An output from the sensors 92 is provided at 96 to a drive 98 (Figure 1) associated with the motor 22. The drive 98 is configured to provide motor control signals based upon the torque that is detected from the coupling 40. In this example, torque is used as the parameter for controlling motor operation instead of position information. Accordingly, the illustrated example allows for an entirely new way of controlling motor operation in an elevator machine. [00028] The drive 98 communicates with an elevator controller 100 that determines a desired movement of an elevator car, for example. The drive 98 utilizes torque information from the coupling 40 (e.g., output signals from the sensors 92) and information from the control 100 to provide appropriate control signals to the motor 22 to achieve a desired motor operation. Given this description, those skilled in the art will be able to design or program a drive to utilize torque information to control a motor of an elevator machine to meet the needs of their particular situation.

[00029] The torque-based motor control approach of the illustrated example allows for using a contact-less torque transducer such as the coupling 40 and eliminates the need for an encoder. One feature of the illustrated example is that it provides direct measurement of torque exhibited through the shaft of the machine assembly 20. The torque sensing coupling 40 provides instantaneous measurement of torque at all times, which provides information useful for motor control. Using torque measurement instead of position indications allows for incorporating additional information about motor performance and elevator motion into a control strategy. [00030] The preceding description is exemplary rather than limiting in nature.

Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.