Patent Publication Number: US-2010116597-A1

Title: Elevator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2008-287027, filed Nov. 7, 2008; and No. 2009-120311, filed May 18, 2009, the entire contents of both of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an elevator provided with a flow generation device. 
     2. Description of the Related Art 
     As buildings have been converted into high-rises, elevators built in such buildings have been developed to achieve higher speeds. However, as a rated speed of an elevator exceeds 400 m/min, aerodynamic noise caused by airflows around an elevator car becomes a problem (for example, see JSME journals (series B), Vol. 59, No. 564 (1993-8), Paper No. 92-1876). 
     The rated speed of an elevator is defined as “referring to a maximum speed when an elevator ascends with a live load acting on a car” under the Building Standards Law. Where elevators are classified depending on speeds, elevators having a rated speed of 45 m/min are classified into a category of “low speed”; elevators having a rated speed of 60 to 105 m/min are classified into a category of “middle speed”; elevators having a rated speed of 120 m/min or higher are classified into a category of “high speed”; and elevators having a rated speed of 360 m/min are classified into a category of “ultra high speed”. 
     Hereinafter, elevators classified into the category “ultra high speed” or “high speed” will be referred to as “high speed elevators”. 
     As a solution to reduce aerodynamic noise of high speed elevators, there is a method for mounting a wind rectification cover on a top end of a car (for example, see Jpn. Pat. Appln. KOKAI Publication No. 4-333486). Further in order to cope with higher speed elevators, a technique of attaching a rectification spoiler onto a rectification cover has been developed (for example, see Jpn. Pat. Appln. KOKAI Publication No. 2005-162496). The technique of the rectification spoiler has been introduced into the world&#39;s highest speed elevator (for example, see World&#39;s Highest Speed 1010 m/min Elevator, Toshiba review, vol. 57, No. 6 (2002)). 
     However, in case of elevators which run in narrow elevation paths, narrow parts such as hall sills exist, in elevation paths, respectively corresponding to floors to which the elevators ascend and descend. When a car passes such a narrow part, local aerodynamic noise (buff sound) is generated and gives rise to a problem that passengers who are in the car or are waiting on a platform feel uncomfortable. 
     As a result of observing such aerodynamic noise during running, it has been known that large noise is generated when a top end part of a rectification cover of a car is about to pass narrow parts in an elevation path (for example, see reduction of aerodynamic noise of ultra high speed elevators, JSME technical lecture meeting, No. 97-76 (1997)). 
     Usually, an elevator runs balanced between a car body and a counter weight having an equal weight to the car body. Therefore, when the counter weight and the car body pass each other at a high speed around an intermediate floor, loud aerodynamic noise is generated around the car as in the case where a car passes a narrow part. 
     For aerodynamic noise generated when passing a narrow part, attaching a rectification spoiler according to the foregoing Jpn. Pat. Appln. KOKAI Publication. No. 2005-162496 is effective. Particularly when a wedge-shaped rectification spoiler is attached, airflows from the rectification spoiler toward the front side of the car are rectified regardless of whether the car is passing a narrow part or not. Accordingly, it is considered that pressure fluctuation is suppressed and aerodynamic noise is reduced. 
     With respect to effect of interference with a counter weight, a nose shape of the counter weight is devised. The effect of interference is considered to be reduced by dividing the counter weight into plural pieces. 
     However, structural modifications as described above require increased costs and are sometimes inapplicable due to limitations of size of an elevation path. In the present circumstances in which elevators are getting higher speeds and comfortableness is required more and more, there is a case that aerodynamic noise can not effectively be reduced by only such structural modifications. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above problems and has as its object to provide an elevator capable of effectively reducing aerodynamic noise occurring when an elevator car passes a narrow part of an elevation path and/or when the elevator car and a counter weight pass each other. 
     According to an aspect of the present invention, there is provided an elevator comprising: a car that ascends and descends in an elevation path; and at least one airflow generation device that is set on a surface of a top end part of at least one of upper and lower end parts of the car, the surface facing a platform of the elevation path, and suppresses a separation flow generated at the top end of the car during running, thereby to generate an airflow for rectifying an airflow flowing into a front side of the car. 
     According to another aspect of the present invention, there is provided an elevator comprising: an elevator comprising: a car that ascends and descends in an elevation path; a counter weight that ascends and descends like a draw bucket in association with the car; and at least one airflow generation device that is set on a top end part of at least one of upper and lower end parts of the counter weight, in a side of the top end part facing the car, and suppresses a separation flow generated at the top end of the counter weight during running, thereby to generate an airflow for rectifying an airflow flowing into a front side of the counter weight. 
     According to another aspect of the present invention, there is provided an elevator comprising: an elevator comprising: a car that ascends and descends in an elevation path; a counter weight that ascends and descends like a draw bucket in association with the car; at least one first airflow generation device that is set on a surface of a top end part of at least one of upper and lower end parts of the car, the surface facing a platform of the elevation path, and suppresses a separation flow generated at the top end of the car during running, thereby to generate an airflow for rectifying an airflow flowing into a front side of the car; and at least one second airflow generation device that is set on a top end part of at least one of upper and lower end parts of the counter weight, in a side facing the car, and suppresses a separation flow generated at the top end part of the counter weight during running, thereby to generate an airflow for rectifying an airflow flowing into a front side of the counter weight. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a view illustrating an airflow generation device using discharge plasma; 
         FIG. 2  is a graph representing an example of change in speed of exciting flows generated by the airflow generation device in  FIG. 1 ; 
         FIG. 3  is a view illustrating an airflow generation device using discharge plasma; 
         FIG. 4  is a graph representing an example of change in speed of exciting flows generated by the airflow generation device in  FIG. 3 ; 
         FIG. 5  is also a graph representing an example of change in speed of exciting flows generated by the airflow generation device in  FIG. 3 ; 
         FIGS. 6A and 6B  are views illustrating a configuration of an elevator according to the first embodiment of the invention wherein  FIG. 6A  is a side view of a car running in an elevation path and  FIG. 6B  is a front view of the car observed in a direction A; 
         FIGS. 7A and 7B  are views illustrating states of airflows occurring at a top end part of a rectification cover wherein  FIG. 7A  illustrates a state of plasma OFF and  FIG. 7B  illustrates a state of plasma ON; 
         FIG. 8  represents a result of measuring pressure fluctuation in case where a car is made run at a predetermined speed in an elevation path in a scale model experiment according to the embodiment; 
         FIG. 9  is a block diagram illustrating a configuration of a control system for airflow generation devices in the embodiment; 
         FIG. 10  is a flowchart representing drive control of the airflow generation devices during running of the car of the elevator according to the embodiment; 
         FIG. 11  is a view illustrating a configuration of a car according to the second embodiment of the invention; 
         FIGS. 12A and 12B  are views illustrating a configuration of an elevator according to the third embodiment of the invention wherein  FIG. 12A  is a side view of a car running in an elevation path and  FIG. 12B  is a front view of the car observed in a direction A; 
         FIG. 13  illustrates a configuration of a car of an elevator according to the fourth embodiment of the invention; 
         FIG. 14  is a side view illustrating configurations of a car and a counter weight of an elevator according to the fifth embodiment of the invention; 
         FIG. 15  is a view illustrating a configuration of the counter weight of the elevator according to the embodiment; 
         FIG. 16  is a view illustrating a configuration of a counter weight of an elevator according to the sixth embodiment of the invention; 
         FIG. 17  is a view illustrating a configuration of a counter weight of an elevator according to the seventh embodiment of the invention; 
         FIG. 18  is a view illustrating a configuration of a counter weight of an elevator according to the eighth embodiment of the invention; 
         FIG. 19  is a side view illustrating configurations of a car and a counter weight of an elevator according to the ninth embodiment of the invention; 
         FIGS. 20A and 20B  are views illustrating a configuration of an elevator according to the tenth embodiment of the invention wherein  FIG. 20A  is a side view of a car running in an elevation path and  FIG. 20B  is a front view of the car observed in a direction A; 
         FIGS. 21A ,  21 B, and  21 C are views illustrating states of airflows occurring at a top end part of a fall guard plate of a car according to the embodiment wherein  FIG. 21A  illustrates a state of plasma OFF,  FIG. 21B  illustrates a state of plasma ON, and  FIG. 21C  illustrates a state of plasma ON on two sides; 
         FIG. 22  represents a result of measuring pressure fluctuation in case where the car is made run at a predetermined speed in an elevation path in a scale model experiment according to the embodiment; 
         FIG. 23  represents another result of measuring pressure fluctuation in case where the car is made run at a predetermined speed in an elevation path in a scale model experiment according to the embodiment; 
         FIG. 24  is a diagram illustrating a configuration of a synthetic jet device according to the eleventh embodiment of the invention; 
         FIGS. 25A and 25B  are views illustrating a configuration of an elevator in case where synthetic jet devices are used as airflow generation devices in the embodiment wherein  FIG. 25A  is a side view of a car running in an elevation path and  FIG. 25B  is a front view of the car from a direction A; 
         FIGS. 26A and 26B  are views illustrating a configuration of an elevator in case where a small fan is used as an airflow generation device according to the twelfth embodiment of the invention wherein  FIG. 26A  is a side view of a car running in an elevation path and  FIG. 26B  is a front view of the car observed in a direction A; 
         FIGS. 27A and 27B  are views illustrating a configuration of an elevator according to the thirteenth embodiment of the invention wherein  FIG. 27A  is a side view of a car running in an elevation path and  FIG. 27B  is a front view of the car observed in a direction A; 
         FIG. 28  represents a result of monitoring aerodynamic noise generated during running of an elevator; 
         FIGS. 29A and 29B  are diagrams in which airflows around a car during running of an elevator are graphically reproduced by Computational Fluid Dynamics wherein  FIG. 29A  graphically represents airflows when a top end part of a fall guard plate is about to pass a narrow part in an elevation path and  FIG. 29B  partially represents part of airflows in front of the car; 
         FIGS. 30A and 30B  graphically represent an analysis result in case where separation flows are suppressed by airflow generation devices wherein  FIG. 30A  graphically represents airflows when a top end part of a fall guard plate is about to pass a narrow part in an elevation path and  FIG. 30B  graphically represents part of flows in front of the car; 
         FIG. 31  is a graph representing a relationship between running speeds of elevators and noise generated when cars pass a narrow part; 
         FIGS. 32A and 32B  are views illustrating a configuration of an elevator according to the fourteenth embodiment of the invention wherein  FIG. 32A  is a side view of a car running in an elevation path and  FIG. 32B  is a front view of the car observed in a direction A; 
         FIGS. 33A and 33B  are views illustrating a configuration of an elevator according to the fifteenth embodiment of the invention wherein  FIG. 33A  is a side view of a car running in an elevation path and  FIG. 33B  is a front view of the car observed in a direction A; and 
         FIGS. 34A and 34B  are views illustrating a configuration of an elevator according to the sixteenth embodiment of the invention wherein  FIG. 34A  is a side view of a car running in an elevation path and  FIG. 34B  is a front view of the car observed in a direction A. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
     The invention is to reduce aerodynamic noise by controlling flows around a car with use of an airflow generation device during running. The airflow generation device is, for example, a device which emits a two-dimensional jet flow from a fan or a device using a synthetic jet. In view of downsizing and controllability of devices, an airflow generation device using discharge plasma is considered most suitable. 
     Airflow generation devices using discharge plasma are described in Jpn. Pat. Appln. KOKAI Publications. No. 2007-317656 and No. 2008-1354. Only a basic configuration thereof will be described below. 
       FIG. 1  is a diagram illustrating a configuration of an airflow generation device using discharge plasma. 
     As illustrated in  FIG. 1 , the airflow generation device  10  is constituted by first and second electrodes  21  and  22  embedded in a dielectric substance  20 , and a discharge power supply  24  which applies a voltage between the electrodes  21  and  22  through a cable  23 . The second electrode  22  and the first electrode  21  are equally distant from a surface of the dielectric substance  20 , and are positioned slightly apart from each other in directions horizontal to the surface of the dielectric substance  20 . 
     Electric insulative material such as glass, polyimide, or rubber is used as the dielectric substance  20 . By using popular copper plates for the electrodes  21  and  22 , the device can be configured to have a thickness of several hundred μm or less. 
     In a configuration as described above, a voltage is applied between the first and second electrodes  21  and  22  from the discharge power supply  24 . When a potential difference reaches a constant threshold or higher, discharge takes place between the first electrode  21  and the second electrode  22 , and exciting flows (airflow)  25  are generated near electrodes. The size and direction of the exciting flows  25  can be controlled by changing the voltage applied between the electrodes  21  and  22  and current-voltage characteristics such as a frequency, current waveform, and a duty ratio. 
     As represented in  FIG. 2 , the exciting flows  25  can be continuously generated by applying an alternating voltage or current between the electrodes  21  and  22 . The example of  FIG. 2  graphically represents a state that exciting flows toward the electrode  21  (e.g., exciting flows toward the left in  FIG. 1 ) and toward the electrode  22  (e.g., exciting flows toward the right) are generated symmetrically. Both exciting flows have substantially equal flow rates. 
     Alternatively, the airflow generation device  10  can be configured as illustrated in  FIG. 3 . 
     In  FIG. 3 , the airflow generation device  10  is constituted by a first electrode  21 , a second electrode  22 , and a discharge power supply  24  which applies a voltage between the electrodes  21  and  22  through a cable  23 . The first electrode  21  is exposed from the same plane as a surface of the dielectric substance  20 . The second electrode  22  and the first electrode  21  are differently distant from the surface of the dielectric substance  20 , and are embedded in the dielectric substance  20 , shifted slightly apart from each other in directions horizontal to the surface of the dielectric substance  20 . That is, the configuration of  FIG. 3  differs from that of  FIG. 1  in that the first electrode  21  is exposed from the same plane as the surface of the dielectric substance  20 . 
     If, in a configuration as described above, an alternating voltage or current having a frequency of a predetermined value or lower is applied between the electrodes  21  and  22 , exciting flows  25  can be generated, as graphed in  FIG. 4 , such that flowing directions of the exciting flows  25  are opposite to each other along the surface of the airflow generation device  10 , which is the surface of the dielectric substance  20 , and the exciting flows  25  oscillate at different flow rates in the respective flowing directions. 
     In the example of  FIG. 4 , directions of exciting flows  25  toward the electrode  22  (e.g., the exciting flow toward the right in  FIG. 3 ) are taken to be positive. In this case, exciting flows  25  toward the electrode  21  (e.g., exciting flows toward the left in  FIG. 3 ) and other exciting flows  25  toward the electrode  22  (e.g., exciting flows toward the right in  FIG. 3 ) are generated and flow at respectively different flow rates. 
     By adjusting a voltage value to be applied, the exciting flows  25  which flow in one direction on time average can be generated, as represented in  FIG. 5 . 
     Documents cited below describe that acceleration of flows on a wing surface can be controlled by such exciting flows as described above. In addition, it has been confirmed that control of flows around a wing can be more efficiently performed by unsteadily controlling discharge. 
     “JSME 85-th Period Fluids Engineering Division Meeting, No. 07-16, ISSN 1348-2882, (2007), OS5-1-503” 
     “JSME journals (series B), Vol. 74, No. 744 (2008-8), Paper No. 08-7006” 
     Described next will be a specific configuration in case of applying the airflow generation device  10  to an elevator. 
     First Embodiment 
       FIGS. 6A and 6B  illustrate a configuration of an elevator according to the first embodiment of the invention.  FIG. 6A  is a side view of a car running in an elevation path.  FIG. 6B  is a front view of the car from a direction A. 
     The elevator according to the present embodiment includes a car  31  having a streamlined shape, which is mainly used in high speed elevators. The car  31  ascends and descends in an elevation path  35  by a rope  34  which is driven by a winder not illustrated. 
     In the elevation path  35 , hall sills  36  are provided for platforms on respective floors. A hall door  38  is provided to be openable/closable on each hall sill  36 . A car door  33  is provided to be openable/closable on a front side of the car  31 . When the car  31  stops at a platform on each floor, the car door  33  opens/closes in engagement with the hall door  38 . 
     Reference symbol  37  in the figures denotes a narrow part formed of a protrusion of a hall sill  36 . When the car  31  passes the narrow part  37 , local aerodynamic noise (buff sound) is generated and results in a problem that passengers in the car  31  or waiting on a platform are made feel uncomfortable. 
     In order to reduce such aerodynamic noise, rectification covers  32   a  and  32   b  having gently curved surfaces covering upper and lower end parts of the car  31  are attached. The rectification covers  32   a  and  32   b  have flat surfaces which face a side of the elevation path  35  facing platforms, and also have opposite surfaces which are formed to be semi-spherical. Plural grooves  31   a  are formed in side surfaces of the car  31 . 
     Separately from such a structural noise reduction solution, airflow generation devices  10   a  and  10   b  using discharge plasma described above are used. The airflow generation devices  10   a  and  10   b  are attached to surfaces of top end parts of the rectification covers  32   a  and  32   b , which face the side of the elevation path  35  facing platforms. Since the airflow generation devices  10   a  and  10   b  each can be constructed as a module based on insulative material such as ceramics, parts of such modules can be easily fixed to the rectification covers  32   a  and  32   b  by screwing or an adhesive. 
     The airflow generation devices  10   a  and  10   b  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven by a drive device  11  at predetermined timings during running of the car  31 . 
     The predetermined timings are, specifically, when the upper end part of the car  31  passes each hall sill  36  during up elevation of the car  31  and when the lower end part of the car  31  passes each hall sill  36  during down elevation of the car  31 . 
     That is, the airflow generation device  10   a  provided on the rectification cover  32   a  is driven to generate exciting flows  25  in a descending direction of the car  31  when a top end part of the rectification cover  32   a  passes each hall sill  36  during an ascent of the car  31 . Meanwhile, the airflow generation device  10   b  provided on the rectification cover  32   b  is driven to generate exciting flows  25  in a ascending direction of the car  31  when a top end part of the rectification cover  32   b  passes each hall sill  36  during a descent of the car  31 . 
     Assuming that the car  31  is descending now, operation and effects of the airflow generation device  10   b  will be described below. 
       FIGS. 7A and 7B  are views illustrating states of airflows occurring at a top end part of a rectification cover.  FIG. 7A  illustrates a state of plasma OFF and  FIG. 7B  illustrates a state of plasma ON. 
     As illustrated in  FIG. 7A , when the top end part of the rectification cover  32   b  is just passing a narrow part  37  such as a hall sill of the elevation path  35  during a descent of the car  31 , air dammed by the top end part of the rectification cover  32   b  abruptly flows into the front side of the car  31 , and local accelerated flows occur in front of the car door  33 . The accelerated flows cause large pressure fluctuation, which results in occurrence of aerodynamic noise. 
     As illustrated in  FIG. 7B , if exciting flows  25  are generated in a direction (i.e., ascending direction) opposite to a moving direction of the car  31  from the airflow generation device  10   b  during a descent of the car  31 , a phenomenon of damming at the top end part of the rectification cover  32   b  is suppressed so that airflows flowing into the front side of the car  31  from the top end part can be rectified. Accordingly, pressure fluctuation is suppressed and aerodynamic noise can be suppressed as a result. 
       FIG. 8  represents a result of measuring pressure fluctuation in case where a car is made run at a predetermined speed in an elevation path in a scale model experiment. The horizontal axis represents time and the vertical axis represents a fluctuation value relative to a pressure before the car passes. In the figure, a continuous line represents a characteristic of plasma OFF, and a broken line represents a characteristic of plasma ON. 
     Abrupt pressure fluctuation occurs when the top end part of the car  31  passes a narrow part  37  on the elevation path  35 . However, if exciting flows  25  are generated in advance in a direction opposite to the moving direction of the car  31  by setting plasma ON, pressure fluctuation thereof is suppressed and aerodynamic noise is reduced accordingly. 
     The above result also applies to an ascent of the car  31 . 
     That is, airflows flowing from the top end part of the rectification cover  32   a  can be rectified by generating exciting flows  25  in a direction (i.e., descending direction) opposite to the moving direction of the car  31  from the airflow generation device  10   a  attached to the top end part of the rectification cover  32   a  when the top end part of the rectification cover  32   a  is about to pass narrow parts  37  such as hall sills  36  on the elevation path  35 . Pressure fluctuation can be thereby suppressed, and aerodynamic noise can be suppressed as a result. 
     Next, a method for driving the airflow generation devices  10   a  and  10   b  will be described with reference to  FIGS. 9 and 10 . 
       FIG. 9  is a block diagram illustrating a configuration of a control system for the airflow generation devices. 
     A drive device  11  is set on the car  31  and includes a battery for supplying electric power required to drive the airflow generation devices  10   a  and  10   b . The drive device  11  supplies electric power to the airflow generation devices  10   a  and  10   b  to drive these devices, based on a drive signal output from a control device  12 . 
     The control device  12  is set in a machine room in a building. The control device  12  is constituted by a computer mounting a CPU, a ROM, a RAM, etc. The control device  12  performs operation control of the entire elevator by staring up a predetermined program. In this case, the control device  12  performs drive control of the airflow generation devices  10   a  and  10   b . The control device  12  and the drive device  11  on the car  31  are electrically connected by a tail code or wirelessly. 
     A car position detection device  13  detects a position of the car  31  running in the elevation path  35  on real time, based on a pulse signal which is output from a pulse encoder (not illustrated) in synchronism with rotation of a winder. 
       FIG. 10  is a flowchart expressing drive control of the airflow generation devices during running of the car. 
     The car  31  is assumed now to be moving at a predetermined speed in an ascending direction (Yes in a step S 11 ). The control device  12  detects a position of the car  31 , based on a position signal output from the car position detection device  13  (step S 12 ). Further, the control device  12  causes the drive device  11  to drive the airflow generation device  10   a  for a predetermined time period (step S 14 ) immediately before the top end part of the rectification cover  32   a  attached to the upper end part of the car  31  passes a hall sill  36  (Yes in a step S 13 ). 
     The foregoing predetermined time period refers to time required until the top end part of the car  31  passes throughout a hall sill  36 . The predetermined time period is about 0.3 to 0.5 seconds though this time period varies depends on speeds of the car  31 . 
     Otherwise, when the car  31  is moving at a predetermined speed in a descending direction (No in the step S 11 ), the control device  12  also detects the position of the car  31 , based on the position signal output from the car position detection device  13  (step S 16 ). Further, the control device  12  causes the drive device  11  to drive the airflow generation device  10   b  for the predetermined time period (step S 18 ) immediately before the top end part of the rectification cover  32   b  attached to the lower end part of the car  31  passes the hall sill  36  (Yes in a step S 17 ). 
     Thus, in the elevator, driving of the airflow generation device  10   a  is controlled at the timing when the top end part of the rectification cover  32   a  passes a hall sill  36  during an ascent. On the other side, driving of the airflow generation device  10   b  is controlled at the timing when the top end part of the rectification cover  32   a  passes a hall sill  36  during a descent. Pressure fluctuation caused when the car  31  passes a hall sill  36  is steadily suppressed by plasma airflows, and accordingly, aerodynamic noise can be reduced. 
     Meanwhile, developments have been started in use of airflow control utilizing discharge plasma in the field of aircrafts. However, this airflow control is usually used to reduce air resistance during movement. In general cases, plasma is always ON. 
     In contrast, in case of the present elevator, the car  31  moves at a high speed in a limited space of the elevation path  35 , unlike in case of moving objects such as aircrafts. At hall sills  35  in the middle of the elevation path  35 , aerodynamic noise occurs due to abrupt pressure fluctuation. Therefore, in order to reduce such aerodynamic noise, drive control particular to elevators is needed, e.g., plasma needs to be switched on at a predetermined timing while detecting the position of a car along an elevation path, as has been described referring to  FIG. 10 . Further, controlling plasma to be switched on/off is also recommended from a viewpoint of energy saving. 
     Only several watt of electric power is required to generate plasma exciting flows. Therefore, this drive power can be easily fed from the car  31 . Since the size of the drive device  11  may therefore be small, the drive device  11  can be easily set on the car  31 . 
     The first embodiment described above assumes a car  31  attached with rectification covers  32   a  and  32   b . If neither the rectification cover  32   a  nor  32   b  is attached, the airflow generation devices  10   a  and  10   b  may be set on a surface of the car  31  facing platforms at upper and lower end parts of the car  31 . Then, the same effects as described above can be obtained. 
     The airflow generation device  10   a  or  10   b  may be set on a surface of the car  31  facing platforms at least one of the upper and lower end parts of the car  31 . 
     Second Embodiment 
     Next, the second embodiment of the present invention will be described below. 
       FIG. 11  illustrates a configuration of a car of an elevator according to the second embodiment of the invention. As in the first embodiment, a rectification cover  32   a  is attached to an upper end part of a car  31 , and a rectification cover  32   b  is attached to a lower end part of the car  31 . 
     In the second embodiment, two airflow generation devices  10   a  and  10   b  are provided on a surface of a top end part of the rectification cover  32   a , which faces a side of an elevation path  35  facing platforms. Similarly, two airflow generation devices  10   c  and  10   d  are provided on a surface of a top end part of the rectification cover  32   b , which faces the side of the elevation path  35  facing platforms. 
     The airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when the top end part of the rectification cover  32   a  passes each hall sill  36  during an ascent of the car  31  and when the top end part of the rectification cover  32   b  passes each hall sill  36  during a descent of the car  31 . 
     The drive device  11  is set on the car  31 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . When the car  31  passes a predetermined position, the control device  12  controls driving of the airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  by the drive device  11 . 
     In the example of  FIG. 11 , the airflow generation devices  10   a  and  10   b  are simultaneously driven to generate exciting flows  25  in a descending direction of the car  31  when the top end part of the rectification cover  32   a  passes each hall sill  36  during an ascent of the car  31 . On the other side, the airflow generation devices  10   c  and  10   d  are simultaneously driven to generate exciting flows  25  in an ascending direction of the car  31  when the top end part of the rectification cover  32   b  passes each hall sill  36  during a descent of the car  31 . 
     Thus, in the car  31  with rectification covers, the airflow generation devices  10   a  and  10   b  are provided on the top end part of the rectification cover  32   a , and the airflow generation devices  10   c  and  10   d  are provided on the top end part of the rectification cover  32   b . In this manner, when the top end parts of the rectification covers  32   a  and  32   b  are about to pass narrow parts  37  such as hall sills  36 , airflows flowing into the front side of the car  31  can be rectified. As a result, pressure fluctuation caused by the narrow parts  37  during high speed running can be suppressed, and generation of aerodynamic noise can accordingly be suppressed. 
     The airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  may be arranged tandem in ascending and descending directions on the top end parts of the rectification covers  32   a  and  32   b , respectively. Alternatively, as illustrated in  FIG. 11 , the airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  may be tilted in a substantial inverted V-shape so that air around the top end parts of the rectification covers  32   a  and  32   b  smoothly flows toward sides. 
     The term of “arranged tandem” is intended to mean, in the example of airflow generation devices  10   a  and  10   b , a layout which causes the airflow generation devices  10   a  and  10   b  to generate exciting flows  25  in ascending and descending directions. 
     The term of “tilted in a substantial inverted V-shape” is intended to mean, in the example of airflow generation devices  10   a  and  10   b , a layout in which these devices are arranged tilted in opposite directions to each other with a predetermined angle maintained to the ascending and descending directions. In this case, exciting flows  25  are generated from the airflow generation devices  10   a  and  10   b , at a predetermined angle to the ascending and descending directions. At this time, the predetermined angle may be experimentally determined so that airflows from a top end part of the car  31  into the front side of the car  31  can be effectively rectified. 
     According to the layouts as described above, flows around the rectification covers can be more effectively rectified, and more reduction of aerodynamic noise can be expected accordingly. 
     Still alternatively, a greater number of airflow generation devices than described above may be used and arranged so as to rectify flows around the rectification covers, and may be driven at predetermined timings, respectively. 
     Third Embodiment 
     Next, the third embodiment of the present invention will be described. 
       FIGS. 12A and 12B  are views illustrating a configuration of an elevator according to the third embodiment of the invention.  FIG. 12A  is a side view of a car running in an elevation path.  FIG. 12B  is a front view of the car observed in a direction A. Components in  FIGS. 12A and 12B  which are common to the configuration in  FIGS. 6A and 6B  according to the first embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     A rectification cover  32   a  is attached to an upper end part of a car  31 , and a rectification cover  32   b  is attached to a lower end part of the car  31 . Further, rectification spoilers  39   a  and  39   b  each having a steep shape are provided on the rectification covers  32   a  and  32   b , protruded in ascending and descending directions. The rectification spoilers  39   a  and  39   b  are members for reducing aerodynamic noise during high speed running, and are fixed onto the rectification covers  32   a  and  32   b  by, for example, screwing so as to protrude in ascending and descending directions. 
     In the third embodiment, two airflow generation devices  10   a  and  10   b  are provided on a surface of a top end part of the rectification spoiler  39   a , which faces a side of an elevation path  35  facing platforms. Similarly, two airflow generation devices  10   c  and  10   d  are provided on a surface of a top end part of the rectification spoiler  39   b , which faces the side of the elevation path  35  facing the platforms. 
     The airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when a top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31  and when a top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     The drive device  11  is set on the car  31 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . When the car  31  passes a predetermined position, the control device  12  controls driving of the airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  by the drive device  11 . 
     In the example of  FIGS. 12A and 12B , the airflow generation devices  10   a  and  10   b  are simultaneously driven to generate exciting flows  25  in a descending direction of the car  31  when the top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31 . On the other side, the airflow generation devices  10   c  and  10   d  are simultaneously driven to generate exciting flows  25  in an ascending direction of the car  31  when the top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     Thus, in the car  31  with rectification spoilers, the airflow generation devices  10   a  and  10   b  are provided on the top end part of the rectification spoiler  39   a , and the airflow generation devices  10   c  and  10   d  are provided on the top end part of the rectification spoiler  39   b . In this manner, when the top end parts of the rectification spoilers  39   a  and  39   b  are about to pass narrow parts  37  such as hall sills  36 , airflows flowing into the front side of the car  31  can be rectified. As a result, pressure fluctuation caused by the narrow parts  37  during high speed running can be suppressed, and generation of aerodynamic noise can accordingly be suppressed. 
     As in the example of  FIGS. 12A and 12B , the airflow generation devices  10   a  and  10   b  and the airflow generation devices  10   c  and  10   d  are arranged tandem in the ascending and descending directions respectively at the top end parts of the rectification spoilers  39   a  and  39   b . In this manner, flows around the rectification spoilers can be more effectively rectified, and more reduction of aerodynamic noise can accordingly be expected. 
     Fourth Embodiment 
     Next, the fourth embodiment of the present invention will be described. 
       FIG. 13  is a diagram illustrating a configuration of a car of an elevator according to the fourth embodiment of the invention. As in the third embodiment, a rectification cover  32   a  and a rectification spoiler  39   a  are attached to an upper end part of a car  31 , and a rectification cover  32   b  and a rectification spoiler  39   b  are attached to a lower end part of the car  31 . 
     In the fourth embodiment, airflow generation devices are provided at a top end part of the rectification cover  32   a , in addition to airflow generation devices attached to top end parts of the rectification spoilers  39   a  and  39   b . That is, in the example of  FIG. 13 , one airflow generation device  10   a  is provided at the top end part of the rectification spoiler  39   a , and two airflow generation devices  10   b  and  10   c  are provided tilted in a substantial inverted V-shape, at the top end part of the rectification cover  32   a . Similarly, one airflow generation device  10   d  is provided at the top end part of the rectification spoiler  39   b , and two airflow generation devices  10   e  and  10   f  are provided tilted in a substantial inverted V-shape, at the top end part of the rectification cover  32   b.    
     The airflow generation devices  10   a  to  10   c  and  10   d  to  10   f  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when a top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31  and when a top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     The drive device  11  is set on the car  31 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . When the car  31  passes a predetermined position, the control device  12  controls driving of the airflow generation devices  10   a  to  10   f  by the drive device  11 . 
     In the example of  FIG. 13 , the airflow generation devices  10   a ,  10   b , and  10   c  are simultaneously driven to generate exciting flows  25  in a descending direction of the car  31  when the top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31 . On the other side, the airflow generation devices  10   d ,  10   e , and  10   f  are simultaneously driven to generate exciting flows  25  in an ascending direction of the car  31  when the top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     Thus, in the car  31  with rectification covers and rectification spoilers, the airflow generation devices  10   a  to  10   c  and the airflow generation devices  10   d  to  10   f  are provided respectively on the top end parts of the rectification covers  32   a  and  32   b  and the rectification spoilers  39   a  and  39   b . In this manner, when the top end parts of the rectification spoilers  39   a  and  39   b  are about to pass narrow parts  37  such as hall sills  36 , airflows flowing into the front side of the car  31  can be rectified. As a result, pressure fluctuation caused by the narrow parts  37  during high speed running can be suppressed, and generation of aerodynamic noise can accordingly be suppressed. 
     Although the airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  are arranged tilted in a substantial inverted V-shape in the example of  FIG. 13 , the airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  may be arranged tandem in ascending and descending directions. 
     Alternatively, a greater number of airflow generation devices than described above may be used and arranged so as to rectify flows around the rectification covers, and may be driven at predetermined timings, respectively. 
     Fifth Embodiment 
     Next, the fifth embodiment of the present invention will be described. 
     In the fifth embodiment, aerodynamic noise and vibration which are generated when a counter weight and a car pass each other are reduced by providing airflow generation devices on a top end of a counter weight. 
       FIG. 14  is a side view illustrating configurations of a car and a counter weight in an elevator according to the fifth embodiment of the invention. Components in  FIG. 14  which are common to configurations in  FIGS. 6A and 6B  according to the foregoing first embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
       FIG. 14  illustrates a state where a car  31  and a counter weight  40  pass each other during a descent of the car  31 . The counter weight  40  is attached to another end of a rope  34 , and is moved in an elevation path  35  along with the car  31  in accordance with driving of a winder not illustrated. 
     When a top end part of the counter weight  40  is about to pass the car  31  in an intermediate floor along the elevation path  35 , there is a problem that local separated flows are generated at the top end part of the counter weight  40 , thereby generating large pressure fluctuation, which generates aerodynamic noise and causes the car  31  to vibrate. 
     In this case, as illustrated in  FIG. 14 , aerodynamic noise and vibration generated when the counter weight  40  and the car  31  pass each other can be reduced to some extent by wedge-shaping a top end of the counter weight  40  so that a side of the wedge-shape close to the back of the car  31  is parallel. However, as the moving speed of the elevator increases, such a structural modification is not enough to satisfactorily reduce aerodynamic noise and vibration. 
     Hence, as illustrated in  FIG. 15 , airflow generation devices  10   c  and  10   d  are provided respectively on surfaces of upper and lower end parts of the counter weight  40  facing the car  31 . As described previously, the airflow generation devices  10   c  and  10   d  each can be constructed as a module based on insulative material such as ceramics. Therefore, parts of such modules can be easily fixed to the counter weight  40  by screwing or an adhesive. 
     The airflow generation devices  10   a  and  10   b  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when a lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31  and when a top end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     The drive device  11  is set on the counter weight  40 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . At the timing when the car  31  and the counter weight  40  pass each other, the control device  12  controls driving of the airflow generation devices  10   a  and  10   b  by the drive device  11 . The control device  12  and the drive device  11  on the counter weight  40  are electrically connected by a cable not illustrated or wirelessly. 
     In the example of  FIG. 14 , the airflow generation device  10   b  is driven to generate exciting flows  25  in a direction (ascending direction) opposite to the moving direction of the counter weight  40  when the lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31 . On the other side, the airflow generation device  10   a  is driven to generate exciting flows  25  in a direction (descending direction) opposite to the moving direction of the counter weight  40  when the upper end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     Thus, the airflow generation devices  10   a  and  10   b  provided on the upper and lower end parts of the counter weight  40  are caused to generate exciting flows  25  in a direction opposite to the moving direction of the counter weight  40 . Then, from the same logic as in the case of the car  31  described referring to  FIGS. 7A and 7B , airflows flowing from the top end part of the counter weight  40  toward a surface of the counter weight  40  facing the car  31  can be smoothly rectified. In this manner, pressure fluctuation caused when the car  31  and the counter weight  40  pass each other can be suppressed, and aerodynamic noise and vibration can accordingly be suppressed. 
     Sixth Embodiment 
     Next, the sixth embodiment of the present invention will be described. 
       FIG. 16  illustrates a configuration of a counter weight according to the sixth embodiment of the invention. A car has the same configuration as that in  FIG. 14  according to the above fifth embodiment. 
     In the sixth embodiment, two airflow generation devices  10   a  and  10   b  are provided on a surface of an upper end part of the counter weight  40 , which faces the car  31 . Similarly, two airflow generation devices  10   c  and  10   d  are provided on the surface of a lower end part of the counter weight  40 , which faces the car  31 . 
     The airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are when a lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31  and when a top end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     The drive device  11  is set on the counter weight  40 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . At the timing when the car  31  and the counter weight  40  pass each other, the control device  12  controls driving of the airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  by the drive device  11 . The control device  12  and the drive device  11  on the counter weight  40  are electrically connected by a cable not illustrated or wirelessly. 
     In the example of  FIG. 16 , the airflow generation devices  10   c  and  10   d  are simultaneously driven to generate exciting flows  25  in a direction (ascending direction) opposite to the moving direction of the counter weight  40  when the lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31 . On the other side, the airflow generation devices  10   a  and  10   b  are driven to generate exciting flows  25  in a direction (descending direction) opposite to the moving direction of the counter weight  40  when the upper end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     Thus, the airflow generation devices  10   a  and  10   b  and the airflow generation devices  10   c  and  10   d  are provided respectively on the upper and lower end parts of the counter weight  40 . Then, airflows flowing from top end parts of the counter weight  40  toward a surface of the counter weight facing the car  31  can be effectively rectified. As a result, pressure fluctuation caused when the car  31  and the counter weight  40  pass each other can be suppressed, and aerodynamic noise and vibration can accordingly be suppressed. 
     The airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  may be arranged tandem in ascending and descending directions. Alternatively, as in the example of  FIG. 16 , the airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  may be tilted in a substantial inverted V-shape so that air around a top end part of the counter weight  40  smoothly flows toward sides. According to such layouts, flows around top end parts of the counter weight  40  can be more effectively rectified, and more reduction of aerodynamic noise can accordingly be expected. 
     Still alternatively, a greater number of airflow generation devices than described above may be used and arranged so as to rectify flows around the rectification covers, and may be driven at predetermined timings, respectively. 
     Seventh Embodiment 
     Next, the Seventh embodiment of the present invention will be described. 
       FIG. 17  illustrates a configuration of a counter weight in an elevator according to the seventh embodiment of the invention. A car has the same configuration as that in  FIG. 14  according to the above fifth embodiment. 
     The seventh embodiment uses a counter weight  41  having a shape divided into two of left and right pieces to reduce aerodynamic noise generated when passing a car  31 . The counter weight  41  is constituted by two columnar weight members  42   a  and  42   b  extended in ascending and descending directions, and a link part  43  which links the weight members  42   a  and  42   b.    
     Airflow generation devices  10   c  and  10   d  are respectively provided on upper end parts of the counter weight  41 , as well as airflow generation devices  10   c  and  10   d  are respectively provided on lower end parts of counter weight  41 . 
     The airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are when a lower end part of the counter weight  41  passes the car  31  during an ascent of the car  31  and when a top end part of the counter weight  41  passes the car  31  during a descent of the car  31 . 
     The drive device  11  is set between the weight members  42   a  and  42   b  of the counter weight  41 . A control device  12  illustrated in  FIG. 9  detects a position of the car  31 , based on a position signal output from a car position detection device  13 . At the timing when the car  31  and the counter weight  41  pass each other, the control device  12  controls driving of the airflow generation devices  10   a ,  10   b ,  10   c , and  10   d  by the drive device  11 . The control device  12  and the drive device  11  on the counter weight  41  are electrically connected by a cable not illustrated or wirelessly. 
     In the example of  FIG. 17 , the airflow generation devices  10   c  and  10   d  are simultaneously driven to generate exciting flows  25  in a direction (ascending direction) opposite to the moving direction of the counter weight  41  when the lower end part of the counter weight  41  passes the car  31  during an ascent of the car  31 . On the other side, the airflow generation devices  10   a  and  10   b  are driven to generate exciting flows  25  in a direction (descending direction) opposite to the moving direction of the counter weight  41  when the upper end part of the counter weight  41  passes the car  31  during a descent of the car  31 . 
     Thus, in the counter weight  41  of a two-piece type, the airflow generation devices  10   a  and  10   b  and the airflow generation devices  10   c  and  10   d  are provided on upper end parts of the weight members  42   a  and  42   b  and on the lower end parts thereof, respectively. In this manner, airflows flowing from top end parts of the counter weight  41  toward a surface of the counter weight  41  facing the car  31  can be rectified. As a result, pressure fluctuation caused when the car  31  and the counter weight  41  pass each other can be suppressed, and aerodynamic noise and vibration can accordingly be suppressed. 
     Eighth Embodiment 
     Next, the eighth embodiment of the present invention will be described. 
       FIG. 18  illustrates a configuration of a counter weight of an elevator according to the eighth embodiment of the invention. A car has the same configuration as that in  FIG. 14  according to the above fifth embodiment. 
     The eighth embodiment uses a counter weight  44  of a three-piece type to reduce aerodynamic noise generated when passing a car  31 . The counter weight  44  is constituted by three columnar weight members  45   a ,  45   b , and  45   c  extended in elevation directions, and link parts  46   a  and  46   b  which link the weight members  45   a ,  45   b , and  45   c.    
     Airflow generation devices  10   a ,  10   b , and  10   c  are provided respectively on upper end parts of weight members  45   a ,  45   b , and  45   c  of the counter weight  44 , and airflow generation devices  10   d ,  10   e , and  10   f  are provided respectively on lower end parts of the weight members  45   a ,  45   b , and  45   c  of the counter weight  44 . 
     A method for driving the airflow generation devices  10   a  to  10   f  is the same as that in the above seventh embodiment. That is, the airflow generation devices  10   d  to  10   f  are simultaneously driven to generate exciting flows  25  in a direction (ascending direction) opposite to the moving direction of the counter weight  44  when the lower end parts of the counter weight  44  pass the car  31  during an ascent of the car  31 . 
     On the other side, the airflow generation devices  10   a  to  10   c  are simultaneously driven to generate exciting flows  25  in a direction (descending direction) opposite to the moving direction of the counter weight  44  when the upper end parts of the counter weight  44  pass the car  31  during a descent of the car  31 . 
     Thus, in the counter weight  44  of a three-piece type, the airflow generation devices  10   a ,  10   b , and  10   c  and the airflow generation devices  10   d ,  10   e , and  10   d  are provided respectively on the upper and lower end parts of the weight members  45   a ,  45   b , and  45   c . In this manner, airflows flowing from the top end parts of the counter weight  44  toward surfaces of the top end parts facing the car  31  can be rectified. As a result, pressure fluctuation caused when the car  31  and the counter weight  44  pass each other can be suppressed, and aerodynamic noise and vibration can accordingly be suppressed. 
     Furthermore, the same description as made above also applies to a counter weight divided into a greater number of pieces than described above. The same effects as described above can be obtained by simply providing airflow generation devices respectively at upper and lower end parts of weight members extended in ascending and descending directions. 
     Ninth Embodiment 
     Next, the ninth embodiment of the present invention will be described. 
       FIG. 19  is a side view illustrating configurations of a car and a counter weight of an elevator according to the ninth embodiment of the invention. Components in  FIG. 19  which are common to configurations in  FIG. 14  according to the fifth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     In the ninth embodiment, both of a car  31  and a counter weight  40  are provided with airflow generation devices. That is, for the car  31 , airflow generation devices  10   a  and  10   b  are provided on surfaces of top end parts of rectification spoilers  39   a  and  39   b , which face a side of an elevation path  35  facing platforms. For the counter weight  40 , airflow generation devices  10   c  and  10   d  are provided on surfaces of upper and lower end parts of the counter weight  40 , which face the car  31 . 
     The airflow generation devices  10   a  and  10   b  provided on the car  31  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a first drive device  11   a  during running of the car  31 . 
     The predetermined timings are, specifically, when a top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31  and when a top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     The first drive device  11   a  is set on the car  31 . A control device  12  illustrated in  FIG. 9 , as a first control unit, detects a position of the car  31 , based on a position signal output from a car position detection device  13 . When the car  31  passes a predetermined position, the control device  12  controls driving of the airflow generation devices  10   a  and  10   b  by the first drive device  11   a.    
     In the example of  FIG. 19 , the airflow generation device  10   a  is driven to generate exciting flows  25  in a descending direction of the car  31  when the top end part of the rectification spoiler  39   a  passes each hall sill  36  during an ascent of the car  31 . On the other side, the airflow generation device  10   b  is driven to generate exciting flows  25  in an ascending direction of the car  31  when the top end part of the rectification spoiler  39   b  passes each hall sill  36  during a descent of the car  31 . 
     The airflow generation devices  10   c  and  10   d  provided on the counter weight  40  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a second drive device  11   b  during running of the car  31 . 
     The predetermined timings are, specifically, when a lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31  and when a top end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     The second drive device  11   b  is set on the counter weight  40 . A control device  12  illustrated in  FIG. 9 , as a second control unit, detects a position of the car  31 , based on a position signal output from a car position detection device  13 . At the timing when the car  31  and the counter weight  40  pass each other, the control device  12  controls driving of the airflow generation devices  10   c  and  10   d  by the drive device  11 . The control device  12  and the drive device  11   b  on the counter weight  40  are electrically connected by a cable not illustrated or wirelessly. 
     In the example of  FIG. 19 , the airflow generation device  10   c  is driven to generate exciting flows  25  in a direction (ascending direction) opposite to the moving direction of the counter weight  40  when the lower end part of the counter weight  40  passes the car  31  during an ascent of the car  31 . 
     On the other side, the airflow generation device  10   d  is driven to generate exciting flows  25  in a direction (descending direction) opposite to the moving direction of the counter weight  40  when the upper end part of the counter weight  40  passes the car  31  during a descent of the car  31 . 
     Thus, the airflow generation devices  10   a  and  10   b  and the airflow generation devices  10   c  and  10   d  are provided on both of the car  31  and the counter weight  40 , and are driven to generate exciting flows  25  at respectively proper timings. In this manner, pressure fluctuation caused when the car  31  passes narrow parts  37  such as hall sills  36  can be suppressed, and aerodynamic noise caused when the car  31  and the counter weight  40  pass each other can be suppressed as well. As a result, an elevator which is felt always comfortable even during high speed running can be provided. 
     The configuration of the car  31  is not limited to the example of  FIG. 19  but may alternatively be arranged such that only rectification covers  32   a  and  32   b  are attached to the upper and lower end parts of the car  31 . Also, the configuration of the counter weight  40  may be of a divided type as illustrated in  FIG. 17  or  18 . 
     Tenth Embodiment 
     Next, the tenth embodiment of the invention will be described. 
     Above descriptions have been made assuming a high speed elevator including a car with rectification covers. However, the invention is not limited to such a high speed elevator but is also effective for an ordinary low speed elevator including a box-shaped car. The term “low speed elevator” herein refers to elevators which run at a “low speed” or “middle speed” according to speed classification under the Building Standards Law described previously. 
     Recently, in order to reduce as much as possible a gap between a platform and a car from a viewpoint of barrier-free, a great number of low speed elevators are designed so that narrow parts of an elevation path are 30 mm or less. In such low speed elevators, loud aerodynamic noise is sometimes generated when a car passes narrow parts of an elevation path even if the car moves at a low speed. 
     A configuration for reducing aerodynamic noise will now be described below assuming such a low speed elevator. 
       FIGS. 20A and 20B  are views illustrating a configuration of an elevator according to the tenth embodiment of the invention.  FIG. 20A  is a side view of a car running in an elevation path.  FIG. 20B  is a front view of the car observed in a direction A. 
     The elevator according to the present embodiment includes a box-shaped car  51  which is mainly used in low speed elevators. The car  51  ascends and descends in an elevation path  35 , by a rope  54  which is driven by a winder not illustrated. 
     A fall guard plate  52  which is commonly known as an “apron” is attached to a lower end part of the car  51  on a side thereof facing platforms. The fall guard plate  52  is a plate member which prevents things from falling through a gap between hall sills  36  of platforms and a car door  53 . The fall guard plate  52  is extended by a predetermined length from an edge of the car door  53  in a descending direction. 
     The elevation path  35  has the same configuration as that illustrated in  FIGS. 6A and 6B . 
     That is, the elevation path  35  is provided with hall sills  36  at platforms on respective floors. A hall door  38  is provided to be openable/closable on each hall sill  36 . In front of the car  51 , the car door  53  is provided to be openable/closable. When the car  51  stops at the platform on each floor, the car door  53  opens/closes in engagement with the hall door  38 . Reference symbol  37  in the figures denotes a narrow part formed by a hall sill  36  in the elevation path  35 . 
     An airflow generation device  10   a  is provided on a surface of a top end part of the car  51 , which faces a side of the elevation path  35  facing platforms. An airflow generation device  10   b  is provided on a surface of a top end part of the fall guard plate  52  attached to a lower end of the car  51 , the surface facing the side of the elevation path  35  facing the platforms. As has been described above, the airflow generation devices  10   a  and  10   b  each can be constructed as a module based on insulative material such as ceramics. Therefore, parts of such modules can be easily fixed to the car  51  and the fall guard plate  52  by screwing or an adhesive. 
     The airflow generation devices  10   a  and  10   b  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  51 . 
     The predetermined timings are, specifically, when the upper end part of the car  51  passes each hall sill  36  during an ascent of the car  51  and when the lower end part of the car  51  passes each hall sill  36  during a descent of the car  31 . 
     The drive device  11  is set on the car  51 . A control device  12  illustrated in  FIG. 9  detects a position of the car  51 , based on a position signal output from a car position detection device  13 . When the car  51  passes a predetermined position, the control device  12  controls driving of the airflow generation devices  10   a  and  10   b  by the drive device  11 . 
     In the example of  FIGS. 20A and 20B , the airflow generation device  10   a  is driven to generate exciting flows  25  in a descending direction of the car  51  when the top end part of the car  51  passes each hall sill  36  during an ascent of the car  31 . On the other side, the airflow generation device  10   b  is driven to generate exciting flows  25  in an ascending direction of the car  51  when the top end part of the fall guard plate  52  passes each hall sill  36  during a descent of the car  51 . 
     Assuming that the car  51  is now descending, operation and effects of the airflow generation device  10   b  will be described below. 
       FIGS. 21A ,  21 B, and  21 C are views illustrating states of airflows occurring at a top end part of a fall guard plate of a car.  FIG. 21A  illustrates a state of plasma OFF.  FIG. 21B  illustrates a state of plasma ON.  FIG. 21C  illustrates a state of plasma ON on two sides. 
     As illustrated in  FIG. 21A , when the top end part of the fall guard plate  52  of the car  51  is about to pass narrow parts  37  such as hall sills  36  on the elevation path  35  during a descent of the car  51 , air dammed by the top end part of the fall guard plate  52  abruptly flows into the front side of the car  51 , and local accelerated flows occur in front of the car door  53 . Further, longitudinal vortices  55  are generated at an end part of the fall guard plate  52 . The longitudinal vortices  55  further accelerate the accelerated flows in front of the car door  53 . Such accelerated flows cause large pressure fluctuation, which results in generation of aerodynamic noise. 
     As illustrated in  FIG. 21B , if exciting flows  25  are generated in a direction (i.e., ascending direction) opposite to the moving direction of the car  51  from the airflow generation device  10   b  during a descent of the car  51 , a phenomenon of damming at the top end part of the fall guard plate  52  is eliminated. Airflows flowing into the front side of the car  51  from the top end part can be thereby smoothly rectified around the car. Accordingly, pressure fluctuation is suppressed, and aerodynamic noise can be suppressed as a result. 
       FIG. 22  represents a result of measuring pressure fluctuation in case where a car is made run at a predetermined speed in an elevation path in a scale model experiment. The horizontal axis represents time and the vertical axis represents a fluctuation value relative to a pressure before the car passes. In the figure, a continuous line represents a characteristic of plasma OFF, and a broken line represents a characteristic of plasma ON. 
     Abrupt pressure fluctuation occurs when the top end part of the car  51  passes a narrow part  37  on the elevation path  35 . However, if exciting flows  25  are generated in advance in a direction opposite to the moving direction of the car  51  by setting plasma ON, pressure fluctuation thereof is obviously suppressed and aerodynamic noise is accordingly reduced. 
     The same result as described above also applies to when the car  31  ascends. 
     That is, airflows flowing from the top end part of the car  51  into the front side thereof can be rectified by generating exciting flows  25  in a direction (i.e., descending direction) opposite to the moving direction of the car  51  from the airflow generation device  10   a  attached to the top end part of the car  51  when the top end part of the car  51  is about to pass the narrow part  37  such as a hall sill  37  on the elevation path  35 . In this manner, pressure fluctuation can be suppressed, and aerodynamic noise can be suppressed as a result. 
     In general, pressure fluctuation during a descent is larger than that during an ascent. This is because, usually, air blows up from downside in the elevation path  35 , although depending on structures of buildings. If the car  51  descends in such an elevation path  35 , longitudinal vortices  55  rapidly grow up and come round into side end parts of the fall guard plate  52  at the narrow parts  37  such as hall sills  36 . 
     Hence, as indicated by broken lines in  FIGS. 20A and 20B , an airflow generation device  10   c  may be added to a back surface (which is opposite to platforms) of the fall guard plate  52 , and the airflow generation devices  10   b  and  10   c  may be simultaneously driven during a descent of the car  51 . In this configuration, action of the longitudinal vortices  55  generated at side end pars of the fall guard plate  52  can be weakened. Accordingly, as illustrated in  FIG. 21C , airflows flowing from the top end part into the front side of the car  51  can be more smoothly rectified, thereby suppressing pressure fluctuation, and generation of aerodynamic noise can accordingly be suppressed. 
       FIG. 23  represents a result of measuring pressure fluctuation in case where the airflow generation devices  10   b  and  10   c  are provided on both surfaces of the fall guard plate  52 . Obviously, pressure fluctuation is suppressed compared with a configuration of providing the airflow generation device  10   b  only on one surface of the fall guard plate  52 . This is because, in the configuration of providing the airflow generation device  10   b  only on one surface of the fall guard plate  52 , the longitudinal vortices  55  cannot be effectively suppressed although accelerated flows are suppressed. 
     Eleventh Embodiment 
     Next, the eleventh embodiment of the present invention will be described. 
     The above first to tenth embodiments have been described assuming that airflow generation devices using discharge plasma are applied to an elevator. Alternatively, however, a synthetic jet device using a small-size vibration film can be used in place of an airflow generation device. 
       FIG. 24  is a diagram illustrating a configuration of a synthetic jet device according to the eleventh embodiment of the invention. 
     The synthetic jet device  60  includes a vibration film  61 . A blow jet flow  62  is generated by vibrating the vibration film  61  by a drive device  63 . Since the synthetic jet device is well known to public, a specific description of a configuration thereof will be omitted herefrom. 
       FIGS. 25A and 25B  are views illustrating a configuration of an elevator in case where synthetic jet devices are used as airflow generation devices.  FIG. 25A  is a side view of a car running in an elevation path.  FIG. 25B  is a front view of the car from a direction A. Components in  FIGS. 25A and 25B  which are common to  FIGS. 20A and 20B  in the above tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     Two synthetic jet devices  60   a  and  60   b  are provided on a surface of a top end part of a box-shaped car  51 , which faces a side of an elevation path  35  facing platforms. A fall guard plate  52  is attached to a lower end part of the car  51 , and two synthetic jet devices  60   c  and  60   d  are provided on a surface of a top end part of the fall guard plate  52 , which faces a side of the elevation path  35  facing platforms. 
     In a configuration as described above, jet flows  62  are generated in a direction (i.e., ascending direction) opposite to the moving direction of the car  51  by driving the synthetic jet devices  60   c  and  60   d  when the top end part of the fall guard plate  52  is about to pass narrow parts  37  such as hall sills  36  during a descent of the car  51 . Then, influence of local accelerated flows around the car can be suppressed, and aerodynamic noise can be thereby suppressed. 
     On the other side, jet flows  62  are generated in a direction (i.e., descending direction) opposite to the moving direction of the car  51  by driving the synthetic jet devices  60   a  and  60   b  when the top end part of the car  51  is about to pass narrow parts  37  such as hall sills  36  during an ascent of the car  51 . Then, influence of local accelerated flows around the car can be suppressed, and aerodynamic noise can be thereby suppressed. 
     The synthetic jet devices  60   a  and  60   b  as well as the synthetic jet devices  60   c  and  60   d  may be arranged tandem in ascending and descending directions. Alternatively, as illustrated in  FIGS. 25A and 25B , the synthetic jet devices  60   a  and  60   b  as well as the synthetic jet devices  60   c  and  60   d  may be tilted in a substantial inverted V-shape. 
     Twelfth Embodiment 
     Next, the twelfth embodiment of the present invention will be described. 
     In the twelfth embodiment, a small fan is used as an airflow generation device. 
       FIGS. 26A and 26B  are views illustrating a configuration of an elevator in case where a small fan is used as an airflow generation device according to the twelfth embodiment of the invention.  FIG. 26A  is a side view of a car running in an elevation path.  FIG. 26B  is a front view of the car observed in a direction A. Components in  FIGS. 26A and 26B  which are common to  FIGS. 20A and 20B  in the above tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     Thin nozzles  70   a  and  70   b  including slit-type nozzle parts are provided on a surface of a top end part of a box-shaped car  51 , which faces a side of an elevation path  35  facing platforms. A fall guard plate  52  is attached to a lower end part of the car  51 . Thin nozzles  70   c  and  70   d  including slit-type nozzle parts are provided on a surface of a top end part of the fall guard plate  52 , which faces a side of the elevation path  35  facing platforms. On the car  51 , there are provided a small fan  72  for feeding winds to the nozzles  70   a ,  70   b ,  70   c , and  70   d , and a drive device  73  for driving the fan  72  to rotate. 
     In a configuration as described above, jet flows  71  are generated in a direction (i.e., ascending direction) opposite to the moving direction of the car  51  from the nozzles  70   c  and  70   d  by driving the fan  72  when the top end part of the fall guard plate  52  is about to pass narrow parts  37  such as hall sills  36  during a descent of the car  51 . Then, influence of local accelerated flows around the car can be suppressed, and aerodynamic noise can be thereby suppressed. 
     On the other side, jet flows  72  are generated in a direction (i.e., descending direction) opposite to the moving direction of the car  51  from the nozzles  70   a  and  70   b  by driving the fan  72  when the top end part of the car  51  is about to pass narrow parts  37  such as hall sills  36  during an ascent of the car  51 . Then, influence of local accelerated flows around the car can be suppressed, and aerodynamic noise can be thereby suppressed. 
     The nozzles  70   a  and  70   b  as well as the nozzles  70   c  and  70   d  may be arranged tandem in ascending and descending directions. Alternatively, as illustrated in  FIGS. 26A and 26B , the nozzles  70   a  and  70   b  as well as the nozzles  70   c  and  70   d  may be tilted in a substantial inverted V-shape. 
     Thirteenth Embodiment 
     Next, the thirteenth embodiment of the present invention will be described. 
     In case of a box-shaped car used in a low speed elevator as described in the foregoing tenth embodiment, noise reduction effect may sometimes be unsatisfactorily obtained due to a relationship with the shape of the car during an ascent even if an airflow generation device is provided on an upper end part of the car. The thirteenth embodiment is to eliminate such a problem. 
       FIGS. 27A and 27B  are views illustrating a configuration of an elevator according to the thirteenth embodiment of the invention.  FIG. 27A  is a side view of a car running in an elevation path. 
       FIG. 27B  is a front view of the car observed in a direction A. Components which are common to  FIGS. 20A and 20B  in the foregoing tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     The present embodiment differs from the tenth embodiment in that a plate-type support member  56  is attached to an edge of an upper end part of the car  51  in a side facing platforms. The plate-type support member  56  is extended in an ascending direction by a predetermined length from the edge of the upper end part of the car  51  in the side facing platforms. An airflow generation device  10   a  is provided on a surface of a top end part of the support member  56 , which faces a side of an elevation path  35  facing platforms. 
     Thus, the airflow generation device  10   a  is provided at an upper end part of the car  51  by the support member  56 . Therefore, pressure fluctuation caused at narrow parts  37  such as hall sills  36  can be suppressed thereby effectively reducing aerodynamic noise, according to the same logics applied to the foregoing case of providing an airflow generation device  10   a  on a fall guard plate  52  as described with reference to  FIGS. 21A ,  21 B, and  21 C. 
     Further, if another airflow generation device  10   d  is set on a back surface of the support member  56  and is driven in the same manner as the airflow generation device  10   a , noise reduction effect can be improved more. 
     A configuration as described above is applicable not only to airflow generation devices using plasma but also to synthetic jet devices (see  FIG. 24 ) described in the foregoing eleventh embodiment and a fan (see  FIGS. 26A and 26B ) described in the foregoing twelfth embodiment. Noise reduction effect during an ascent can be attained by providing such a synthetic jet device or a fun on an upper end part of a box-shaped car for a low speed. 
     Further, in each of the above embodiments, airflows generated during running can be controlled by providing airflow generation devices on a car or counter weight. Positions and a method to attach airflow generation devices, and a method for generating airflows can be appropriately modified in practice. 
     The above embodiments have been described assuming that a control device of an elevator controls driving of airflow generation devices. However, a control device for controlling driving of airflow generation devices may be configured to be provided separately and set on a car or a counter weight, together with a drive device. 
     A method for detecting a position of a car is not limited to a method using a pulse encoder. For example, plural position sensors may be provided in an elevation path, and the position of a car may be detected based on signals output from the position sensors. 
     (Aerodynamic Noise Generation Mechanism) 
     As a supplementary description of airflow generation devices described above, a mechanism of generating aerodynamic noise (buff sound) during running of an elevator will be described in details below, referring to examples of low to high speed elevators. 
     In accordance with recent popularization of barrier-free, a gap between hall sills and a car is demanded to be narrower and narrower so that wheels of wheelchairs and baby buggies may not run off. Therefore, narrow parts in an elevation path are so narrowed that even low to high speed elevators which have not ever caused troubles come to cause local aerodynamic noise (buff sound) when cars pass such narrow parts. 
     In low to high speed elevators, a fall guard plate  52  which is commonly known as an “apron” is attached to a lower end part of a car  51  on a side facing platforms, as has been described referring to  FIGS. 20A and 20B . The fall guard plate  52  is extended by a predetermined length from an edge of a car door  53  in a descending direction. 
       FIG. 28  represents a result of monitoring aerodynamic noise generated during running while measuring car positions, with respect to low to high speed elevators having a shape as described above. 
     In  FIG. 28 , the horizontal axis represents time, and the vertical axis represents noise loudness. When a car  51  is made descend at a predetermined speed, large pressure fluctuation is caused and aerodynamic noise is generated, at an instance when a top end part of a fall guard plate  52  is about to pass a narrow part  37  (see an arrow in the figure). 
     Hence, airflows around a car during running of an elevator were reproduced by Computational Fluid Dynamics (CFD), and causes of generating aerodynamic noise were specified and represented graphically in  FIGS. 29A and 29B . 
       FIG. 29A  represents airflows when a top end part of the fall guard plate  52  provided on a lower end part of the car  51  was about to pass a narrow part  37  in an elevation path.  FIG. 29B  is a front view of partially extracted airflows within a frame of a broken line in  FIG. 29A . 
     When the top end part of the fall guard plate  52  is about to pass narrow parts  37 , airflows are dammed by the top end part of the fall guard plate  52  and cause large pressure fluctuation, thereby generating aerodynamic noise. 
     Particularly, as represented in  FIG. 29B , Computational Fluid Dynamics have revealed that separation bubbles  56  exist at the top end part of the fall guard plate  52  and promote pressure fluctuation. 
     That is, pressure loss at a gap between a car  51  and narrow parts  37  increases due to the separation bubbles  56  occurring at the top end part of the fall guard plate  52 , and damming effect is promoted. As a result, longitudinal vortices  55  abruptly grow and enter from two sides of the fall guard plate  52 . Airflows from the top end part of the longitudinal vortices  55  are converged at a center part in front of the car  51 , and accelerate as contracted accelerating flows  57 . The longitudinal vortices  55  and the contracted accelerating flows  57  abruptly reduce pressure in front of the car, according to Bernoulli&#39;s Theorem, and causes large pressure fluctuation. 
     As expressed in  FIGS. 20A and 20B , if exciting flows  25  are now generated at the top end part of the fall guard plate  52  by the airflow generation device  10   b , separation flows at the top end part of the fall guard plate  52  are suppressed by the exciting flows  25 , and generation of the longitudinal vortices  55  are weakened. In this manner, convergence of streamlines of flows in front of the car  51  is suppressed. 
       FIGS. 30A and 30B  express analysis results in case where suppressing separation flows by generating exciting flows  25  at the top end part of the fall guard plate  52 . Obviously, the separation bubbles  56  at the top end part of the fall guard plate  52  are contracted by generation of the exciting flows  25 , and the longitudinal vortices  55  and the contracted accelerating flows  57  are accordingly suppressed and rectified. 
     Thus, pressure fluctuation can be suppressed and aerodynamic noise can accordingly be reduced by rectifying disturbance of airflows which is caused when the top end part of the fall guard plate  52  is about to pass narrow parts  37 . 
     Meanwhile, aerodynamic noise generated during running of an elevator or an automobile is caused by nonsteady motion of vortices existing in airflows disturbed by the running. Such aerodynamic noise can be calculated from a wave equation (Lighthill&#39;s equation) which is obtained by transforming Navier-Stokes equations as fundamental hydrodynamic equations. The wave equation is cited below as equation 1. 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           
                             
                               
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     The above equation 1 is further transformed and subjected to dimensional analysis to evaluate orders of respective terms. Accordingly, sound radiation from an aerodynamic noise source can be expressed as follows. 
     
       
         
           
             
               
                 
                   
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     In the above equation 2, sound pressure p=c 2 ρ, ρ 0  is an average value of concentrations; r denotes a distance from a sound source;  1  denotes a scale of a vortex; and u is a speed. 
     The first term in the above equation 2 indicates that aerodynamic noise accompanied by volume change of airflows, such as upwelling and suctioning flows, is generated in proportion to the fourth power of a speed. The second term indicates that noise generated by change in quantity of motion, such as noise from an automobile or Shinkansen (Bullet Train) running at a high speed, is proportional to the sixth power of a speed. The third term indicates that noise caused by nonsteady motion of disturbance, such as jet sound of a jet engine, is generated in proportion to the eighth power of a speed. 
       FIG. 31  represents a result of measuring noise when a car passes a narrow part while changing a running speed, with respect to low to high speed elevators. The horizontal axis represents moving speeds of cars, and the vertical axis represents noise loudness. 
     Obviously, noise generated when passing a narrow part increases in proportion to the fourth power of a running speed. This implies that noise generated when passing a narrow part is caused by change in volume of airflows due to abrupt influx of air when a top end part of the car is about to pass a narrow part. Therefore, in order to reduce aerodynamic noise at the time when a narrow part is passed, it is considered effective to suppress change in volume of airflows at this time, i.e., to suppress pressure fluctuation. 
     Even from high speed elevators having a car  31  having a streamlined shape as illustrated in  FIGS. 6A and 6B , aerodynamic noise is generated on the same principles as described above. 
     In a high speed elevator, as has been described referring to  FIGS. 7A and 7B , air dammed at a top end part of a rectification cover  32   b  abruptly flows into the front side of a car  31 , thereby generating local accelerated flows. Large pressure fluctuation is caused by the accelerated flows, and aerodynamic noise is generated as a result. 
     In this case, exciting flows  25  are generated in an ascending direction (during a descent) from an airflow generation device  10   b  illustrated in  FIGS. 6A and 6B , and separation flows formed at the top end part of the rectification cover  32   b  are thereby suppressed. Accordingly, airflows in front of the car are rectified, and pressure fluctuation can be thereby suppressed. 
     Fourteenth Embodiment 
     Next, the fourteenth embodiment of the present invention will be described. 
       FIGS. 32A and 32B  are views illustrating a configuration of an elevator according to the fourteenth embodiment of the invention.  FIG. 32A  is a side view of a car running in an elevation path.  FIG. 32B  is a front view of the car observed in a direction A. Components which are common to  FIGS. 20A and 20B  in the foregoing tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     The present embodiment differs from the tenth embodiment in areas where airflow generation devices are provided. That is, according to the fourteenth embodiment, an airflow generation device  10   a  is set on a top end part of a box-shaped car  51 , so as to lie laterally and cover the top end part entirely in widthwise directions thereof. Similarly, an airflow generation device  10   b  is set on a top end part of a fall guard plate  52  attached to a lower end part of the car  51 , so as to lie laterally and cover the top end part entirely in widthwise directions thereof. 
     The term of “lie laterally” is intended to mean a state that, where the airflow generation devices  10   a  and  10   b  each have a rectangular parallelepiped shape, a lengthwise direction of each of bodies of the devices is arranged in a direction perpendicular to ascending and descending directions, and a generation direction of airflows is oriented in the ascending and descending directions. 
     The airflow generation devices  10   a  and  10   b  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when the upper end part of the car  51  passes each hall sill  36  during an ascent of the car  51  and when the top end part of the fall guard plate  52  passes each hall sill  36  during a descent of the car  51 . In this case, the airflow generation device  10   a  is a target to be driven during an ascent of the car  51 , and the airflow generation device  10   b  is a target to be driven during a descent of the car  51 . 
     Jet ranges of exciting flows  25  spread by thus providing the airflow generation devices  10   a  and  10   b  so as to cover the car  51  and the fall guard plate  52  entirely in the widthwise directions, respectively. Accordingly, airflows flowing into the front side of the car can be rectified more effectively, and aerodynamic noise can be thereby reduced. 
     Fifteenth Embodiment 
       FIGS. 33A and 33B  are views illustrating a configuration of an elevator according to the fifteenth embodiment of the invention.  FIG. 33A  is a side view of a car running in an elevation path.  FIG. 33B  is a front view of the car observed in a direction A. Components which are common to  FIGS. 20A and 20B  in the foregoing tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     The present embodiment differs from the tenth embodiment in locations where airflow generation devices are provided. That is, according to the fifteenth embodiment, airflow generation devices  10   a  and  10   b  are respectively provided on two sides of an upper end part of a box-shaped car  51 , in a manner that the airflow generation devices  10   a  and  10   b  stand longitudinally so as to jet exciting flows  25  toward outside of the car  51 . 
     Similarly, airflow generation devices  10   c  and  10   d  are respectively provided on two sides of a lower end part of a fall guard plate  52  attached to the car  51 , in a manner that the airflow generation devices  10   a  and  10   b  longitudinally stand so as to jet exciting flows  25  toward outside of the car  51 . 
     The term of “longitudinally stand” is intended to mean a state that, where the airflow generation devices  10   a  and  10   b  as well as the airflow generation devices  10   c  and  10   d  each have a rectangular parallelepiped shape, lengthwise directions of each of bodies of these devices are arranged in ascending and descending directions, and generation of airflows is oriented in a direction perpendicular to the ascending and descending directions. 
     The airflow generation devices  10   a  to  10   d  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings during running of the car  51 . 
     The predetermined timings are, specifically, when a top end part of the car  51  passes each hall sill  36  during an ascent of the car  51  and when a top end part of the fall guard plate  52  passes each hall sill  36  during a descent of the car  51 . In this case, the airflow generation devices  10   a  and  10   b  are targets to be driven during an ascent of the car  51 , and the airflow generation devices  10   b  and  10   d  are targets to be driven during a descent. 
     Thus, if the airflow generation devices  10   a  to  10   d  are provided on two sides of each of the car  51  and the fall guard plate  52  and are each caused to generate outward exciting flows  25 , influence of influx from two sides of each of the car  51  and the fall guard plate  52  can be reduced when passing narrow parts  37 , and airflows can be thereby rectified in front of the car. As a result, abrupt pressure fluctuation is suppressed, and aerodynamic noise can be suppressed accordingly. 
     Sixteenth Embodiment 
       FIGS. 34A and 34B  are views illustrating a configuration of an elevator according to the sixteenth embodiment of the invention.  FIG. 34A  is a side view of a car running in an elevation path.  FIG. 34B  is a front view of the car from a direction A. Components which are common to  FIGS. 20A and 20B  in the foregoing tenth embodiment will be denoted at common reference symbols, and descriptions thereof will be omitted herefrom. 
     The present embodiment differs from the tenth embodiment in locations where airflow generation devices are provided. That is, according to the sixteenth embodiment, airflow generation devices  10   a  and  10   b  as well as airflow generation devices  10   e  and  10   f  are respectively provided on two sides of a box-shaped car  51  in a manner that the airflow generation devices  10   a  and  10   b  as well as  10   e  and  10   f  stand longitudinally so as to jet exciting flows  25  toward outside of the car  51 . 
     Similarly, airflow generation devices  10   c  and  10   d  are respectively provided on two sides of a lower end part of a fall guard plate  52  attached to the car  51 , so that the airflow generation devices  10   a  and  10   b  longitudinally stand so as to jet exciting flows  25  toward outside of the car  51 . 
     The term of “longitudinally stand” is intended to mean a state that, where the airflow generation devices  10   a  and  10   b ,  10   c  and  10   d , as well as  10   e  and  10   f  each have a rectangular parallelepiped shape, lengthwise directions of each of bodies of these devices are arranged in ascending and descending directions, and generation of airflows is oriented in a direction perpendicular to the ascending and descending directions. 
     The airflow generation devices  10   a  to  10   f  each have a configuration as illustrated in  FIG. 1  or  3 , and are driven at predetermined timings by a drive device  11  during running of the car  31 . 
     The predetermined timings are, specifically, when a top end part of the car  51  passes each hall sill  36  during an ascent of the car  51  and when a top end part of the fall guard plate  52  passes each hall sill  36  during a descent of the car  51 . In this case, the airflow generation devices  10   a  and  10   b  are targets to be driven during an ascent of the car  51 , and the airflow generation devices  10   b  and  10   d  are targets to be driven during a descent. 
     The airflow generation devices  10   e  and  10   f  are used during both an ascent and a descent. Accordingly, the airflow generation devices  10   a  and  10   b  and the airflow generation devices  10   e  and  10   f  are driven during an ascent. The airflow generation devices  10   c  and  10   d  and the airflow generation devices  10   e  and  10   f  are driven during a descent. 
     Thus, if the airflow generation devices  10   a  to  10   f  are provided along ascending and descending directions on two sides of each of the car  51  and the fall guard plate  52  and are each caused to generate outward exciting flows  25 , influence of influx from two sides of each of the car  51  and the fall guard plate  52  can be reduced when passing narrow parts  37 , and airflows can be thereby rectified in front of the car. As a result, abrupt pressure fluctuation is suppressed, and aerodynamic noise can be suppressed accordingly. 
     Further, if the airflow generation devices  10   e  and  10   f  provided at intermediate positions are used during both an ascent and a descent, influx from two sides of each of the car  51  and the fall guard plate  52  can be effectively prevented. Therefore, effect of reducing aerodynamic noise can be improved. 
     Alternatively, the configurations illustrated in  FIGS. 32B and 33B  may be combined so as to arrange airflow generation devices in a rectangular U-shaped layout on each of top ends of the car  51  and the fall guard plate  52 . Exciting flows  25  may then be generated in two directions, i.e., an ascending or descending direction and a direction perpendicular to the ascending or descending direction. 
     Still alternatively, airflow generation devices may be provided on a counter weight not illustrated. 
     Still alternatively, airflow generation devices may be provided on a car  31  having a streamlined shape as illustrated in  FIGS. 6A and 6B . 
     The foregoing fourteenth to sixteenth embodiments have been described assuming airflow generation devices using discharge plasma. However, synthetic jet devices described in the foregoing eleventh embodiment and a fan described in the foregoing twelfth embodiment are applicable, as airflow generation devices, to these embodiments in the same manner as described above. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.