Abstract:
An image pickup apparatus comprise a camera unit for photographing a subject and a driving device for driving the camera unit in a circumferential angle direction and an elevation angle direction, wherein the driving device includes a motor which drives the camera unit in the circumferential angle direction, and a motor which drives the camera unit in the elevation angle direction, and each of the motor and the motor is constituted of a permanent magnet motor including a planetary reduction gear.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-109664, filed Apr. 9, 2001, the entire contents of which are incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an image pickup apparatus and driving apparatus in which two shafts substantially crossing at right angles to each other can be used to position objects such as a small-sized camera in a circumferential angle direction and elevation angle direction.  
           [0004]    2.Description of the Related Art  
           [0005]    In some of conventional driving apparatuses, as disclosed, for example, in Jpn. Pat. Appln. KOKAI Publication Nos. 1997-47003, 1995-77247, and 1999-18366, a planetary reduction gear is disposed inside a motor rotor.  
           [0006]    Moreover, as disclosed, for example, in Jpn. Pat. Appln. KOKOKU Publication No. 1994-3251 and Jpn. Pat. Appln. KOKAI Publication No. 1998-257358,a universal head is connected to an output shaft of a driving motor via the planetary reduction gear.  
           [0007]    These are known examples, but a concrete constitution for rotating the head in a circumferential angle direction and elevation angle direction is not disclosed, and the head can be rotated in only one direction. Moreover, the examples do not disclose a constitution for disposing a wiring so as to prevent the wiring from disturbing the rotation, for example, even when a small-sized camera is laid on the universal head. During the rotation, it is a very important matter that the wiring does not disturb the rotation.  
         BRIEF SUMMARY OF THE INVENTION  
         [0008]    An object of the present invention is to determine a rotation position of a body with respect to both a circumferential angle direction and an elevation angle direction, and another object is to prevent rotation from being disturbed by a wiring connected to the body during the rotation.  
           [0009]    According to the present invention, there is provided an image pickup apparatus comprising: an image pickup device for photographing a subject; and a driving device for driving the image pickup device in a circumferential angle direction and an elevation angle direction, wherein the driving device includes a first driving device which drives the image pickup device in the circumferential angle direction, and a second driving device which drives the image pickup device in the elevation angle direction, and each of the first driving device and the second driving device is constituted of a permanent magnet motor including a planetary reduction gear.  
           [0010]    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  
       [0011]    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.  
         [0012]    [0012]FIG. 1 is a partially cutaway side view of an image pickup apparatus of the present invention.  
         [0013]    [0013]FIG. 2 is a longitudinal sectional view showing a permanent magnet motor according to a first embodiment for use in the image pickup apparatus.  
         [0014]    [0014]FIG. 3 is a longitudinal sectional view showing the permanent magnet motor according to a second embodiment for use in the image pickup apparatus.  
         [0015]    [0015]FIG. 4 is a longitudinal sectional view showing the permanent magnet motor according to a third embodiment for use in the image pickup apparatus. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    A first embodiment in the present invention will be described hereinafter with reference to the drawings. FIG. 1 is a partially cutaway side view of an image pickup apparatus  1  of the present invention. The image pickup apparatus  1  includes a frame  2  having a circular plate shape and having an opening in the middle thereof, and a transparent cover  3  with which the upper surface of the frame  2  is covered. A motor (first driving device)  11  is attached to the opening of the frame  2 , while a rotation shaft  11   a  is disposed in a vertical direction. Moreover, a base  12  on which a camera unit  14  is laid as described later is attached to the tip end of the rotation shaft  11   a  so as to be freely rotatable along a circumferential angle direction C.  
         [0017]    A motor (second driving device)  13  is attached to the base  12 , while a rotation shaft  13   a  is disposed in a horizontal direction. Moreover, the camera unit  14  is attached to the tip end of the rotation shaft  13   a  so as to be freely rotatable along the elevation angle direction E.  
         [0018]    Each of the motors  11 ,  13  is constituted of a permanent magnet motor. When the motor  11  is driven, the base  12  is driven in the circumferential angle direction C. When the motor  13  is driven, the camera unit  14  is driven in an elevation angle direction E.  
         [0019]    [0019]FIG. 2 is a longitudinal sectional view showing the motor  11 . Additionally, since the motor  11  is the same as the motor  13 , the motors can be used in common, and this results in cost reduction of the image pickup apparatus  1 . The structure of the motor  11  will representatively be described hereinafter.  
         [0020]    For example, six stator coils  16  are arranged inside a motor housing  17  formed of a magnetic material. A rotor  18  is constituted of a permanent magnet and, for example, eight poles are magnetized. Moreover, the rotor  18  is supported by a rotation shaft  19 , and can rotate around the rotation shaft  19  via a bearing  20 . Here, for the rotation of the rotation shaft  19 , when a general three-phases (six coils) motor is assumed, the motor can be driven by successively supplying power to the coils inside the motor housing  17 .  
         [0021]    Furthermore, a speed reduction mechanism by a wonder planetary gear is incorporated in the motor  11 . That is, inside the rotor  18 , a pinion gear  21  is coaxially fixed to the rotation shaft  19 . Moreover, in the outer periphery of the pinion gear  21 , three planetary gears  23  are disposed so as to be rotatable around the rotation shaft  19  or on their own axes, while mutual relative positions are maintained by a carrier  22 . The planetary gear  23  meshes with the pinion gear  21  and fixed internal gear  24 . Additionally, the fixed internal gear  24  is disposed coaxially with the rotation shaft  19  and fixed onto the motor housing  17 .  
         [0022]    On the other hand, the planetary gear  23  also meshes with a rotary internal gear  25  (having the number of teeth different from the number of teeth of the fixed internal gear  24 ) disposed coaxially with the rotation shaft  19 . The rotary internal gear  25  is disposed so as to be rotatable on its own axis, and is connected to a driving shaft  26 . That is, with the rotation of the rotary internal gear  25  on its own axis, the driving shaft  26  is supported by a bearing  27  and rotated.  
         [0023]    With this constitution, the wonder planetary gear is formed. Here, particularly when the wonder planetary gear is used, a holding torque is large even with a small size, and the motor can be stopped in an optional position. When the wonder planetary gear is formed inside the motor housing  17  as described above, a reduction ratio of the driving shaft  26  to the rotation shaft  19  can be enlarged, and a large torque can be obtained.  
         [0024]    Concretely, assuming that the number of teeth of the pinion gear  21  is 15, the number of teeth of the planetary gear  23  is 20, the number of teeth of the fixed internal gear  24  is 54, the number of teeth of the rotary internal gear  25  is 57, and a module is 0.1, the reduction ratio is 87.4.  
         [0025]    Moreover, the driving device of the circumferential angle direction C and elevation angle direction E can be small-sized. Furthermore, since the gear mechanism is used, the holding torque is applied, and the rotation can be held in the optional position.  
         [0026]    Furthermore, according to the present invention, in the driving apparatus in which the similar motors are used to drive two shafts, a unit with various gear mechanisms integrally formed therein as described above can be manufactured by attaching a driving object (here, camera unit  14 ) to the driving shaft  26 . As a result, a manufacturing process can be simplified.  
         [0027]    [0027]FIG. 3 is a longitudinal sectional view showing a motor  11 A according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that a rotation shaft  48  and driving shaft  49  have a hollow pipe structure in the motor  11 A for driving the apparatus in the circumferential angle direction C. Other constitutions are substantially similar to those of the first embodiment.  
         [0028]    For example, six stator coils  36  are disposed inside a motor housing  37  formed of the magnetic material. Moreover, a rotor  38  is constituted of the permanent magnet and, for example, eight poles are magnetized. Furthermore, the rotor  38  is supported on a rotation shaft  48 , and can rotate around the rotation shaft  48  via a bearing  47 . Here, for the rotation of the rotation shaft  48 , when the general three-phases (six coils) motor is assumed, the apparatus can be driven by successively supplying power to the coils in the motor housing  37 .  
         [0029]    Moreover, the speed reduction mechanism by the wonder planetary gear is incorporated in the motor  11 A. That is, inside the rotor  38 , a pinion gear  41  is coaxially fixed to the rotation shaft  49 . Moreover, in the outer periphery of the pinion gear  41 , three planetary gears  43  are disposed so as to be rotatable around the rotation shaft  49  or on their own axes, while the mutual relative positions are maintained by a carrier  42 . The planetary gear  43  meshes with the pinion gear  41  and fixed internal gear  44 . Additionally, the fixed internal gear  44  is disposed coaxially with the rotation shaft  49  and fixed onto the motor housing  37 .  
         [0030]    On the other hand, the planetary gear  43  also meshes with a rotary internal gear  45  (having the number of teeth different from the number of teeth of the fixed internal gear  44 ) disposed coaxially with the rotation shaft  49 . The rotary internal gear  45  is disposed so as to be rotatable on its own axis, and is connected to a driving shaft  46 . That is, with the rotation of the rotary internal gear  45  on its own axis, the driving shaft  46  is supported by the bearing  47  and rotated.  
         [0031]    Different from the first embodiment, since the rotation shaft  48  and driving shaft  49  have the hollow pipe structure, a space for passing a wiring is produced. That is, with the hollow pipe structure, in addition to advantages of the first embodiment, a wiring for supplying power to the motor  13  and camera unit  14  which rotate in the elevation angle direction E can be disposed without hindering the rotation.  
         [0032]    [0032]FIG. 4 is a longitudinal sectional view showing a motor  11 B according to a third embodiment of the present invention. The third embodiment is different from the second embodiment in that a rotation shaft  60  and driving shaft  71  have a hollow pipe structure, and a slip ring  73  (conductive member) is attached to the driving shaft  71  in the motor  11 A for driving the apparatus in the circumferential angle direction C. Moreover, a brush  74  electrically connected to the slip ring  73  is disposed outside the driving shaft  71 . With this constitution, the wiring for supplying power to the motor  13  and camera unit  14  which rotate further in the elevation angle direction E can be disposed without hindering the rotation as compared with the second embodiment. Other constitutions are similar to those of the first embodiment. That is, the speed reduction mechanism by the wonder planetary gear is incorporated in a motor  11 B.  
         [0033]    For example, six stator coils  36  are disposed inside a motor housing  57  formed of the magnetic material. Moreover, a rotor  58  is constituted of the permanent magnet and, for example, eight poles are magnetized. Furthermore, the rotor  58  is supported on a rotation shaft  59 , and can rotate around the rotation shaft  60  via a bearing  55 . Here, for the rotation of the rotation shaft  60 , when the general three-phases (six coils) motor is assumed, the apparatus can be driven by successively supplying power to the coils in the motor housing  57 . Additionally, the rotation shaft  60  is rotatably supported by the motor housing  57  via bearings  60   a,    60   b.    
         [0034]    Furthermore, inside the rotor  58 , a pinion gear  61  is coaxially fixed to the rotation shaft  60 . Moreover, in the outer periphery of the pinion gear  61 , three planetary gears  63  are disposed so as to be rotatable around the rotation shaft  60  or on their own axes, while the mutual relative positions are maintained by a carrier  62 . The planetary gear  63  meshes with the pinion gear  21  and fixed internal gear  64 . Additionally, the fixed internal gear  64  is disposed coaxially with the rotation shaft  60  and fixed onto the motor housing  57 .  
         [0035]    On the other hand, the planetary gear  63  also meshes with a rotary internal gear  65  (having the number of teeth different from the number of teeth of the fixed internal gear  64 ) disposed coaxially with the rotation shaft  60 . The rotary internal gear  65  is disposed so as to be rotatable on its own axis, and is connected to the driving shaft  71 . That is, with the rotation of the rotary internal gear  65  on its own axis, the driving shaft  71  is supported by the bearings  60   a,    60   b  and rotated. This constitution forms the wonder planetary gear.  
         [0036]    Different from the second embodiment, since the rotation shaft  60  and driving shaft  71  have the hollow pipe structure, the space for passing the wiring is produced. That is, with the hollow pipe structure, in addition to the advantages of the first embodiment, a wiring for supplying power to the motor  13  and camera unit  14  which rotate in the elevation angle direction E can be disposed without hindering the rotation.  
         [0037]    Additionally, the camera unit  14  is used here, but this is not limited as long as the object requires the wiring, and the number of poles of the motor is not limited. Moreover, the present invention can be applied both to the inner rotor type permanent magnet motor and the outer rotor type permanent magnet motor.  
         [0038]    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 invention concept as defined by the appended claims and their equivalents.