Patent Application
20080047784
This application claims the benefits of German application No. 10 2006 040 231.6 filed Aug. 28, 2006 and is incorporated by reference herein in its entirety.
The invention relates to a door operating mechanism for an automatic door, in particular for an automatic sliding and/or elevator door, with at least one door leaf, comprising a motor for generating a driving force and a belt or chain guided in the opening or closing direction of the door for transmitting the driving force to the door leaf, the motor being mounted in such a way that its shaft is aligned perpendicular to the opening or closing direction of the door and/or horizontally.
Such door operating mechanisms or similar are known from EP 0 837 536 B11, DE 101 31 211 A1, DE 20 2005 006 404 U1, WO 00/39017 A1 and DE 1953 242 A.
In the field of automatic doors, particularly in the case of elevator doors, it is necessary to make the door operating mechanism as compact as possible, because the door operating mechanism must be mounted so as to be concealed from the elevator user and therefore the installation space for the door operating mechanism also affects the compactness and costs of an elevator system as a whole.
In the case of the door operating mechanism disclosed in DE 101 31 211 A1, a geared motor is present. Gears produce unwanted noise and friction losses leading to rapid wear and costs because of the large number of moving mechanical parts.
The object of the invention is to specify a door operating mechanism which avoids the disadvantages of gears, yet is of compact construction.
With respect to the door operating mechanism referred to in the introduction, this object is achieved according to the invention by an angular encoder for generating an angle signal proportional to the angle of rotation of the motor, said encoder being disposed coaxially to the motor shaft.
This makes possible a particularly compact arrangement that is deflection-free and therefore low-loss in respect of the driving force.
It is particularly advantageous that the motor is disposed - preferably completely inside a door header or lintel at the top of the door, in particular above an elevator car. Ideally no installation space is required above the car of the elevator system for installing or assembling the door operating mechanism. This has specific advantages over a reduction gear solution in which the motor generally has to be mounted above the door header.
In the context of the invention, door header is to be understood as any cross beam rigidly mounted to the door frame, in particular a horizontal section between the lower door system and an upper part, in the case of an elevator the upper part of the car. The door header is generally disposed above the door leaf or leaves.
According to a particularly preferred embodiment, a driving pinion or belt pulley for driving the belt or chain is mounted to the motor shaft.
This has on the one hand the advantage of compactness, on the other, that the belt or chain can be driven gearlessly and/or without reduction gearing by the motor. Gears would significantly increase the axial extent of the overall motor/gear system compared to a gearless drive mechanism. A reduction gear would likewise increase the space requirement, because the driving force would first have to be transmitted from the motor shaft via the reduction gear to an abaxially located double pinion that in turn first drives the belt or chain. The driving pinion or belt pulley is in particular fixed to an unsupported end of the shaft, thereby providing the advantage of universal incorporability into the door system.
The above described mounting of the motor has the further advantage that one and the same motor, e.g. held as a spare part, can be mounted to the door header both at the left- and the right-hand end or anywhere in between, thereby obviating the need to differentiate between left and right output shaft, as is necessary with geared motors.
According to another preferred embodiment, the motor together with driving pinion or belt pulley extends less than 100 mm in the shaft direction, preferably less than 80 mm. In addition, the diameter and/or edge length of the motor is in the range 50 to 200 mm, preferably in the range 80 to 160 mm. With such dimensions, the motor together with driving pinion or belt pulley can be accommodated even in a door lintel or door header having particularly small height and/or width dimensions of less than 110 mm.
Preferably the length of the motor measured without bearing, driving pinion and any electronic components is less than 60 mm, in particular less than 36 mm.
Preferably also, the length of the motor—measured at a distance of at least 35 mm from the shaft—without bearing, driving pinion and any electronic components is less than 60 mm, preferably less than 36 mm.
In another advantageous variant, the motor has a driving torque of at least 0.008 Nm/kg or at least 0.01 Nm/kg door mass, in particular a driving torque in the range 3.0 to 4.5 Nm, preferably in the range 3.5 to 4.0 Nm.
According to another particularly preferred embodiment, the motor is of electronically commutated and/or brushless design, thereby enabling the above mentioned embodiments to be implemented in a particularly advantageous and compact manner.
In an electronically commutated motor, the mechanical commutation system, i.e. the commutator brushes, are replaced by a motor-mounted control unit, also known as a BL controller (brushless controller). In this controller, e.g. a plurality of high-current silicon chips and a programmed microprocessor assume the function of the brushgear, i.e. the wear- and interference-prone interaction of copper segments and carbon brushes.
Dispensing with the brush system has the advantage of reducing noise, the advantage of reducing wear and costs because of a smaller number of moving mechanical parts, and the advantage of eliminating fouling caused by brush abrasion.
The motor is also preferably embodied as a synchronous motor, in particular a permanent-field synchronous motor.
In addition, the door operating mechanism preferably has a control unit with installed control program for moving the door to its open and/or closed position.
In particular, the control unit is designed in such a way that the motor at least during normal operation—is operated at a speed of less than 600 rpm, preferably at a speed of less than 500 rpm.
According to another preferred embodiment, the angular encoder is mounted on the side of the motor facing away from the driving pinion or belt pulley.
According to a preferred embodiment, the angle signal of the angular encoder is used for controlling a commutation circuit for electronic commutation of the motor.
According to another preferred embodiment, the angle signal of the angular encoder is fed as an input variable to a door positioning device.
It is particularly preferred that the angle signal of the angular encoder is used for both of the above-mentioned purposes, resulting in particular savings in respect of installation space, complexity and cost.
For a compact design and in particular for accommodation within the door header or door lintel, it is particularly advantageous that the angular encoder extends max. 40 mm, preferably max. 20 mm, in the axial direction.
It is appropriate for the overall length of motor, driving pinion or belt pulley and angular encoder in the direction of the shaft to be less than 110 mm, or preferably less than 98 mm.
In addition, the angular encoder preferably has a resolution of at least 10 bits/360°, in particular at least 11 bits/360° or at least 12 bits/360°. This is particularly advantageous in conjunction with a low-speed, high-torque motor. In the case of a gearless drive mechanism, a high time resolution is possible even at low rotation speeds, thereby enabling even very low door speeds to be adjusted down to standstill. In addition, the high resolution with a gearless drive mechanism and in particular with sinusoidal control of the motor results in virtually harmonics-free torque development which is characterized by good concentricity with low noise levels.
It is particularly advantageous if the angular encoder is embodied as an absolute encoder.
In the context of the invention, absolute encoder is taken to mean an angle measuring device which outputs position information in the form of a possibly coded numerical value which is unique over the entire resolution range of the absolute encoder, so that no initial reference or calibration pass is necessary, as in the case of an incremental encoder, for example.
The absolute encoder can preferably resolve at least one revolution (360°) completely and is embodied in particular as a single-turn encoder.
An absolute encoder has the advantage over a Hall effect sensor or a quadrature encoder that the rotor position is immediately available at all times, i.e. even immediately after connection of the electricity supply system. This eliminates the hitherto necessary synchronization of the rotor angle on the basis of a reference point or complex calculation. Moreover there is a considerable cost advantage compared to a resolver solution in terms of the encoder itself, but also in respect of the implementation of the control device (control electronics). In addition, less installation space is required compared to a resolver solution.
In addition, an angular encoder is preferably present which employs a magnetic principle and is embodied in particular as a magnetic absolute encoder.
The magnetic absolute encoder or rotary encoder employs in particular the GMR effect. The GMR (giant magneto resistance) effect is a quantum mechanics effect observed in thin film structures made of alternating ferromagnetic and nonmagnetic layers.
Processing is preferably performed in a Wheatstone resistance bridge. This can produce a sine/cosine signal in the two legs of the bridge, thereby enabling each position to be identified through 360°.
The magnetic absolute encoder or angular encoder is alternatively formed by interconnecting a plurality of Hall effect sensors, preferably 3 or 6 Hall sensors. Intelligent processing electronics, e.g. DSP-based, allows unambiguous detection of the entire 360°.
Although using a magnetic absolute encoder for position determination for an automatic door and/or for commutating the motor is particularly advantageous if the driving pinion or belt pulley is mounted directly to the motor shaft, the use of a magnetic absolute encoder for operating or controlling an automatic door is also important independently thereof and must be regarded as an independent solution, as only thus can significant advantages for the door operating mechanism be achieved.
The rotor position is known at each instant i.e. even immediately after application of voltage or current, thereby obviating the need for synchronization of the rotor angle.
Specifically, the high angular resolution produces a high time resolution even at low rotational speeds, so that even very slow door speeds can be adjusted down to a standstill.
Sinusoidal motor control produces virtually harmonics-free torque development which is characterized by very good concentricity with minimal noise.
Low costs.
Low overall height.
An exemplary embodiment of a door operating mechanism according to the invention will now be explained in greater detail with reference to FIGS. 1 to 5 in which:
Mounted coaxially to the motor shaft 11, i.e. on the illustrated axis of rotation A of the motor 10, is a magnetic absolute angular encoder 20. This is explained in greater detail in
Depth L2 of the angular encoder 20: approx. 30 mm.
Depth L1 of the motor 10 and driving pulley 12 together: approx. 80 mm.
Overall depth or overall length L: less than 110 mm.
The angular encoder 20 is located on the side of the motor 10 facing away from the driving pulley 12 and is mounted centrally with respect to the axis A of the motor 10. The angle of rotation (p is indicated in the Figure. The control unit 24 supplies the motor 10 with power in a controlled and regulated manner from a power source 26 such as the public AC supply via a line 28. The angular encoder 20 communicates an analog or coded numerical angle value to the control device 24 via a line 22. The resolution of the combination of angular encoder 20 and control unit 24 is 12 bits, producing an angular resolution of 360°/4096=0.09° for 360°.
The control device 24 of the door operating mechanism has a commutation circuit 32 for electronically commutating and/or sinusoidally modulating the motor 10 embodied as a synchronous or an asynchronous motor. The angle signal 22 is fed to the commutation circuit 32. The high resolution of the angular encoder 20 is fully required for this purpose. This arrangement is particularly advantageous for an electronically commutated (EC) and brushless permanent field synchronous motor 10, preferably gearless, because there is a considerable price advantage compared to rotary resolvers (synchros) used for commutation with identical functionality. In the case of an EC motor the commutation circuit 32 can be termed a BL controller.
The control device 24 of the door operating mechanism additionally has, as a functional unit a door positioning device 34 to which the angle signal 22 is likewise fed. The door positioning device 34 controls the door status and/or the door position. With the numerical angle value, the position of the door leaves 2 and 3 is known via the diameter of the driving pinion 12 used, so that the control unit 24 or the door positioning device 34 can perform service runs to the open or closed position or service test runs in the known manner to determine such end positions. A low and not the full resolution of the angular encoder 20 is required for this purpose.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 040 231.6 | Aug 2006 | DE | national |
