JP2009058870A - Lens barrel rotation drive mechanism and lens barrel rotation type imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve smooth rotation drive and to reduce the space of a rotation drive mechanism, even in the case of a lens barrel to which an accessory lens is attached and a big heavy lens barrel. <P>SOLUTION: A lens barrel rotation drive mechanism includes a tilt motor 51 exerting driving force for rotating a lens barrel 40 and a first step pulley 54, a second step pulley 55 and a third step pulley 56, which are for transmitting the driving force in parallel, while reducing the rotation speed of the tilt motor 51. The first step pulley 54 and the third step pulley 56 being an odd-numbered step for speed reduction and the second step pulley 55 being an even-numbered step for speed reduction are rotated around different center axes of rotation (a rotating shaft 43 and a rotating shaft 44). The first step pulley 54 being the odd-numbered step for speed reduction and the third step pulley 56 being the odd-numbered step for speed reduction are rotated around the same center axis of rotation (the rotating shaft 43). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens barrel rotation driving mechanism and a lens barrel rotation type imaging device for rotating a lens barrel to which an imaging lens is attached in a horizontal direction or a vertical direction. More specifically, the present invention relates to a technology that can realize downsizing of the entire image pickup apparatus while enabling smooth rotation driving with respect to a lens barrel to which an accessory lens is attached or a large lens barrel.

  Examples of the lens barrel rotating type imaging device in which the lens barrel rotates include a video conference video camera and a surveillance video camera. These video cameras are arranged in a horizontal direction ( Hereinafter, it can be rotated in the “pan direction”) and in the vertical direction (hereinafter referred to as “tilt direction”). When shooting at conference halls, universities, churches, etc., an accessory lens (for example, a wide conversion lens) is attached to the lens barrel in order to capture the subject at an appropriate size, such as zooming on the stage or projecting the venue wide. And tele-conversion lenses).

  In addition, in order to capture a subject with high resolution, it is necessary to use a large lens barrel with a large lens attached thereto. In order to position the subject at the center of the photographed image, the lens barrel with the accessory lens or a large lens barrel must be finely rotated toward the subject. A mechanism is required. Furthermore, downsizing is required so that the installed video camera is not conspicuous.

  Here, conventionally, a direct method and a deceleration method are known as rotation drive mechanisms in the pan direction or the tilt direction. In the direct method, a drive motor (drive source) that exerts a rotational driving force is directly connected to a pedestal that can rotate while supporting a lens barrel, and does not have a speed reduction means such as a gear. Therefore, although it is advantageous for downsizing, the minimum driving angle cannot be reduced, and it is disadvantageous for rotating a large and heavy lens barrel (a lens barrel with an accessory lens or a large lens attached). It is a simple method.

On the other hand, there are mainly two types of deceleration methods, one-stage deceleration and two-stage deceleration. In the case of one-stage deceleration or two-stage deceleration, the reduction ratio can be increased compared to the direct method, so that not only the minimum drive angle is reduced, but also the attachment of the accessory lens is possible in terms of weight that can be rotated. It is also excellent against an increase in load due to the eccentric center of gravity caused by.
However, high image quality and high definition of imaging devices are a trend of the times, and recently, video cameras for video conferences and the like are required to be high-definition images. The lens barrel is further increased in size and weight so that an HD (High Definition) image quality can be taken. HD high-quality accessory lenses are also large and heavy.

Therefore, a speed reduction method of three or more speed reductions capable of realizing a larger speed reduction ratio than before is known. In other words, as a power transmission mechanism of the camera, a plurality of pulleys and a plurality of spur gears are combined to transmit the driving force in parallel while reducing the rotational speed of the driving motor to three or more stages (for example, Patent Document 1).
JP 2003-344917 A

  However, since the number of stages of deceleration becomes very large at three-stage deceleration or more, the rotational drive mechanism becomes larger than that of one-stage deceleration or two-stage deceleration. In particular, when the driving force is transmitted in parallel while reducing the rotational speed of the driving motor by combining three or more speed reducing members (pulleys and spur gears) as in the technique of Patent Document 1 above, A very large space is required. In addition, since the lens barrel is enlarged in order to obtain HD image quality, if the rotational drive mechanism is increased, the entire imaging apparatus must be much larger than the conventional one.

Therefore, in order to realize space saving while increasing the reduction ratio, instead of combining multiple spur gears to transmit the driving force in parallel, a worm wheel gear is adopted as the speed reduction means, and the driving force is set at a right angle. There is known a technique capable of decelerating while transmitting (see, for example, Patent Document 2 and Patent Document 3).
JP 2001-223919 A JP 2003-198883 A

  However, if the driving force is transmitted at a right angle while the rotational speed of the driving motor is reduced by the worm wheel gear as in the techniques of Patent Document 2 and Patent Document 3 described above, there is a problem that the transmission efficiency of the driving force is deteriorated. is there. That is, the worm wheel gear loses most of the driving force due to slipping of the gear portion and the like, and the transmission efficiency of the driving force is reduced to about 0.3. The heavy lens barrel cannot be rotated. Therefore, when rotating a lens barrel having an accessory lens or a high-performance large and heavy lens barrel capable of shooting with HD image quality, the techniques of Patent Document 2 and Patent Document 3 cannot be employed.

  Accordingly, the problem to be solved by the present invention is to enable smooth rotation driving even with a lens barrel having an accessory lens attached or a large and heavy lens barrel. Another object of the present invention is to reduce the minimum drive angle of the lens barrel and to save the space of the rotation drive mechanism so that the entire imaging apparatus can be reduced in size.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 of the present invention is a lens barrel rotation driving mechanism for rotating a lens barrel to which an imaging lens is attached in a horizontal direction or a vertical direction, and rotates the lens barrel. A driving source that exerts a driving force to be driven, and three or more speed reducing members for transmitting the driving force in parallel while reducing the driving speed of the driving source. The odd speed reduction members and the even speed reduction members that are even stages of deceleration rotate around different rotation center axes, and each of the odd speed reduction members rotates around the same rotation center axis. To do.

  According to a sixth aspect of the present invention, there is provided a lens barrel to which an imaging lens is attached, and a lens barrel rotation driving mechanism for rotating the lens barrel in a horizontal direction or a vertical direction. The lens barrel rotation type imaging device includes: a lens barrel rotation driving mechanism; a driving source that exerts a driving force for rotating the lens barrel; and a driving force while decelerating the driving speed of the driving source. Three or more speed reduction members for transmitting in parallel, and among the speed reduction members, the odd speed reduction members that are odd speed stages and the even speed reduction members that are even speed stages are different rotation center axes. The odd number reduction members are all rotated about the same rotation center axis.

(Function)
According to the first and sixth aspects of the present invention, as the lens barrel rotation driving mechanism, a driving source that exerts a driving force for rotating the lens barrel, and a driving force while reducing the driving speed of the driving source. And three or more speed reduction members for transmitting in parallel. That is, the driving speed of the driving source is reduced by three or more stages by three or more speed reducing members (speed reducing members capable of transmitting driving force in parallel) with good transmission efficiency. Therefore, the transmission efficiency of the driving force is not deteriorated as in the case of decelerating by the worm wheel gear (deceleration means that transmits the driving force at a right angle), and a large reduction ratio can be realized.

  Also, among the deceleration members, the odd number reduction members that are odd-numbered stages of deceleration and the even-numbered speed reduction members that are even-numbered stages of deceleration rotate around different rotation center axes, and each odd-numbered speed reduction member has the same rotation. Rotate around the central axis. Therefore, even if there are three or more speed reduction members, each odd speed reduction member (for example, the first speed reduction member and the third speed reduction member) is installed so as to overlap the direction of the rotation center axis. Space can be reduced.

  According to the above invention, since the transmission efficiency of the driving force of the driving source that rotates the lens barrel does not deteriorate, the lens barrel with the accessory lens attached or the high-performance lens barrel capable of shooting with HD image quality can be used. Thus, even a large and heavy lens barrel can be rotated by a small drive source (such as a small drive motor). Even if three or more speed reducing members are used, the planar installation space of each speed reducing member can be narrowed, so that not only can it be rotationally driven at a small minimum driving angle, but also the entire imaging apparatus can be miniaturized.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the following embodiments, a video camera 10 for videoconferencing is given as an example of the lens barrel rotation type imaging device of the present invention. The video camera 10 according to the present embodiment can capture an HD (High Definition) image quality by rotating the lens barrel 40 in the pan direction or the tilt direction so that the lens 41 faces the subject. The lens barrel 40 can be attached with a high-quality accessory lens for HD (a wide conversion lens, a teleconversion lens).

FIG. 1 is a perspective view showing a video camera 10 of the present embodiment.
As shown in FIG. 1, the video camera 10 of the present embodiment is installed in a conference room or the like by a base pedestal 20 and can be used for a video conference or the like. That is, the base pedestal 20 supports the rotary pedestal 30 so as to be rotatable. The rotating pedestal 30 supports the lens barrel 40 rotatably. The lens barrel 40 is attached with an imaging lens 41 and the like. For this reason, if the rotating base 30 is rotated and the optical axis of the lens 41 is photographed toward the attendees of the conference, a video conference or the like can be performed.

  Here, if the base pedestal 20 is installed horizontally, the rotary pedestal 30 rotates in the pan direction with the vertical axis shown in FIG. 1 as the rotation center axis. Therefore, the lens 41 can be directed to each of the attendees and the like who are present in front of the conference table. In this case, since the vertical axis that is the rotation center axis of the rotating pedestal 30 intersects the optical axis of the lens 41, even if the lens barrel 40 rotates with the rotation of the rotating pedestal 30, The optical axis always passes through the vertical axis (the center axis of rotation in the pan direction).

  Further, the lens barrel 40 rotates in the tilt direction with respect to the rotating base 30 with the horizontal axis shown in FIG. Therefore, the lens 41 can be moved up and down according to the height of the attendees of the conference and the height of the presentation screen. The horizontal axis that is the rotation center axis of the lens barrel 40 intersects with the optical axis of the lens 41 and is orthogonal to the vertical axis that is the rotation center axis of the rotation base 30, so that the rotation base 30 and the lens barrel 40 are connected to each other. By appropriately rotating, the direction of the lens 41 is three-dimensionally maintained while maintaining the intersection of the optical axis, the vertical axis (rotation center axis in the pan direction), and the horizontal axis (rotation center axis in the tilt direction) at a fixed position. It is possible to control the lens 41 and to direct the lens 41 in the left, right, up and down directions.

Thus, the video camera 10 of the present embodiment can rotate the lens barrel 40 in the pan direction and the tilt direction. Even if the lens barrel 40 is a large and heavy lens barrel 40 that can shoot HD image quality, or the lens barrel 40 is large and heavy when an accessory lens (not shown) is attached, the minimum minimum due to sufficient driving force. Since it is rotationally driven at the drive angle, it is possible to capture a subject such as a conference attendee at an appropriate size and high resolution at the center of the captured image.
Then, next, the rotation drive mechanism of the lens barrel 40 in the video camera 10 of the present embodiment will be described.

FIG. 2 is a perspective view showing the internal structure of the video camera 10 of the present embodiment.
As shown in FIG. 2, the lens barrel 40 is supported by the lens chassis 42 so that the optical axis of the lens 41 is orthogonal to the horizontal axis (rotation center axis in the tilt direction). A rotation shaft 43 is provided for rotation in the direction. The rotation shaft 43 is rotatably supported by the tilt chassis 31 inside the rotation base 30 (see FIG. 1) so as to coincide with the horizontal axis that is the rotation center axis in the tilt direction. Therefore, the lens barrel 40 (lens 41) supported by the tilt chassis 31 via the rotation shaft 43 of the lens chassis 42 rotates in the tilt direction with respect to the tilt chassis 31 together with the lens chassis 42.

  Further, the tilt chassis 31 is supported so as to be rotatable with respect to the base pedestal 20 (see FIG. 1) about a vertical axis that is a rotation center axis in the pan direction. Therefore, in the lens barrel 40 (lens 41) supported by the tilt chassis 31 via the rotation shaft 43 of the lens chassis 42, the optical axis of the lens 41 is orthogonal to the vertical axis (rotation center axis in the pan direction). Together with the lens chassis 42 and the tilt chassis 31, it rotates in the pan direction with respect to the base pedestal 20.

  In this way, the lens barrel 40 (lens 41) can rotate in the tilt direction together with the lens chassis 42 with respect to the rotating base 30 (tilt chassis 31) shown in FIG. Yes. Further, the lens barrel 40 (lens 41) can rotate in the pan direction together with the lens chassis 42 and the tilt chassis 31 with respect to the base pedestal 20 shown in FIG. Although not shown, an imaging element such as a CCD (Charge Coupled Devices) device or a CMOS (Complementary Metal Oxide Semiconductor) device is attached to the rear end of the lens barrel 40, so that the lens barrel 40 ( If the lens 41) is rotated in the tilt direction or the pan direction, light incident on the lens 41 from that direction is imaged on the imaging surface of the imaging device. Then, the light and darkness of the image is photoelectrically converted into the amount of electric charge, which is sequentially read out and converted into an electric signal, so that the subject in that direction is photographed.

  Here, rotation of the lens barrel 40 in the tilt direction and pan direction (rotation of the lens chassis 42 and tilt chassis 31) is performed by a rotation drive mechanism (tilt rotation drive mechanism 50, pan rotation drive mechanism 70). That is, the video camera 10 of the present embodiment includes a tilt motor 51, a vibration damper 52, a timing belt 53, a first-stage pulley 54, a second-stage pulley 55, and a third-stage pulley 56 as a rotation driving mechanism in the tilt direction. And a tilt rotation drive mechanism 50 (corresponding to the lens barrel rotation drive mechanism in the present invention). The first-stage pulley 54, the second-stage pulley 55, and the third-stage pulley 56 correspond to the speed reducing member in the present invention.

  All such tilt rotation drive mechanisms 50 are arranged on the left side surface of the tilt chassis 31. That is, the tilt motor 51 is mounted via the vibration damper 52, between the tilt motor 51 and the first-stage pulley 54, between the first-stage pulley 54 and the second-stage pulley 55, and the second-stage pulley 55, Between the third-stage pulleys 56, timing belts 53 are respectively wound. The first-stage pulley 54 is rotatably attached to the rotation shaft 43 of the lens chassis 42, and the third-stage pulley 56 is fixedly attached to the rotation shaft 43. The pulley 54 and the third-stage pulley 56 rotate separately around the same rotation center axis (horizontal axis).

  Therefore, if the tilt motor 51 of the tilt rotation drive mechanism 50 is rotated, the driving force is transmitted to the first-stage pulley 54 by the timing belt 53. At this time, the rotational speed of the tilt motor 51 is decelerated (first stage), and the vibration damper 52 and the timing belt 53 prevent the generation of vibration and noise. Similarly, the rotational speed is decelerated (second stage) from the first-stage pulley 54 to the second-stage pulley 55 and transmitted to the third-stage pulley 56 from the second-stage pulley 55 (three-stage pulley). Eyes) and transmitted. Then, the lens chassis 42 and the lens barrel 40 (lens 41) rotate in the tilt direction around the rotation axis 43 (horizontal axis).

  In addition, the video camera 10 of the present embodiment includes a pan rotation driving mechanism 70 as a rotation driving mechanism in the pan direction. The pan rotation drive mechanism 70 includes a pan motor 71, a vibration damper 72, a timing belt 73, a geared pulley 74, a final spur gear 75, and a fixed plate 76. The pan rotation driving mechanism 70 shown in FIG. 2 does not correspond to the lens barrel rotation driving mechanism in the present invention.

  Here, all of the pan rotation drive mechanism 70 is disposed below the tilt chassis 31, and the pan motor 71 is attached to the fixed plate 76 via a vibration damper 72. A pulley 74 with gears is also attached to the fixed plate 76, and a timing belt 73 is wound around the pan motor 71 and the pulley 74 with gears. The pan motor 71, the timing belt 73, and the geared pulley 74 are fixed to the inside of the base pedestal 20 (see FIG. 1) by a fixing plate 76, and the final spur gear 75 is located between the base pedestal 20 and the tilt chassis 31. The spur gear 74a of the geared pulley 74 and the final spur gear 75 are engaged with each other.

  Therefore, when the pan motor 71 of the pan rotation driving mechanism 70 is rotated, the driving force is transmitted in parallel to the geared pulley 74 by the timing belt 73. At this time, the rotational speed of the pan motor 71 is decelerated (first stage), and the occurrence of vibration, noise, and the like is prevented by the damping damper 72 and the timing belt 73. Also, the rotational speed is reduced (second stage) from the pulley 74 with gears to the final spur gear 75 and transmitted in parallel to rotate the tilt chassis 31 in the pan direction, so that the lens barrel 40 (lens 41) is a lens. It rotates in the pan direction together with the tilt chassis 31 via the chassis 42.

  Thus, in the video camera 10 of the present embodiment, the lens barrel 40 (lens 41) is rotated in the tilt direction by the tilt rotation drive mechanism 50, and is also rotated in the pan direction by the pan rotation drive mechanism 70. In order to reduce the load when the lens barrel 40 is rotationally driven as much as possible, the horizontal axis that is the rotation center axis in the tilt direction and the vertical axis that is the rotation center axis in the pan direction are close to the center of gravity of the lens barrel 40. It is set to pass through the position. The horizontal axis may be separated from the center of gravity so that the height of the video camera 10 does not increase.

However, when an accessory lens (not shown) is attached to the lens barrel 40, the position of the center of gravity of the lens barrel 40 is greatly displaced in the direction of the lens 41, so that the load when rotating the lens barrel 40 in the tilt direction is increased. Increase. Therefore, the tilt rotation drive mechanism 50 must be able to exhibit a larger driving force than the pan rotation drive mechanism 70 so as to cope with an increase in load due to the eccentric center of gravity. Further, in order to realize the downsizing of the video camera 10, it is necessary to save the space for the tilt rotation driving mechanism 50.
Next, the tilt rotation drive mechanism 50 of the present invention that can obtain a large driving force and saves space will be described in detail.

FIG. 3 is a perspective view showing the tilt rotation drive mechanism 50 in the video camera 10 of the present embodiment.
As shown in FIG. 3, the tilt rotation drive mechanism 50 includes a tilt motor 51, a vibration damper 52, timing belts 53 a to 53 c, a first-stage pulley 54, a second-stage pulley 55, and a third-stage pulley 56. ing.

  Here, the tilt motor 51 includes a drive shaft 51 a and is fixed to the lower portion of the left side surface of the tilt chassis 31 with screws via a vibration damper 52. Therefore, the vibration generated as the tilt motor 51 rotates is attenuated by the action of the vibration damper 52 and is not transmitted to the tilt chassis 31.

  The first-stage pulley 54 includes a large pulley 54 a that receives a driving force transmitted from a timing belt 53 a wound around the drive shaft 51 a of the tilt motor 51, and a second-stage pulley that is one stage after the first-stage pulley 54. And a small pulley 54b that transmits a driving force to the timing belt 53b wound around the pulley 55. Furthermore, the second-stage pulley 54 includes a large pulley 55a that receives the driving force transmitted from the timing belt 53b that is wound around the first-stage pulley 54 that is one stage before, and a third-stage pulley that is one stage after the pulley. 56 is provided with a small pulley 55b that transmits a driving force to a timing belt 53c wound around 56. Further, the third-stage pulley 56 (corresponding to the final reduction member in the present invention) is a large pulley 56a that receives the driving force transmitted from the timing belt 53c that is wound around the second-stage pulley 54 that is the preceding stage. It has.

  Such a tilt rotation drive mechanism 50 is disposed on the left side surface of the tilt chassis 31. That is, the tilt chassis 31 rotatably supports the rotation shaft 43 of the lens chassis 42 to which the lens barrel 40 is fixed, and the first-stage pulley is mounted on the rotation shaft 43 protruding from the upper part of the left side surface of the tilt chassis 31. 54 is inserted. Therefore, the first-stage pulley 54 is rotatable with respect to the rotation shaft 43 on the left side surface of the tilt chassis 31. The driving force of the tilt motor 51 is reduced by noise such as meshing of spur gears by the timing belt 53a wound between the drive shaft 51a of the tilt motor 51 and the large pulley 54a of the first-stage pulley 54. The vibration is transmitted in parallel to the first stage pulley 54 without generating vibration. Moreover, since the diameter of the large pulley 54a of the first-stage pulley 54 is set to be very large compared to the diameter of the drive shaft 51a of the tilt motor 51, the rotational speed of the tilt motor 51 is such that the rotational speed of the tilt motor 51 is the same as that of the drive shaft 51a and the large pulley 54a. And is transmitted to the first-stage pulley 54.

  A rotation shaft 44 projects from the center of the left side surface of the tilt chassis 31, and a second-stage pulley 55 is inserted into the rotation shaft 44 so as to be rotatable. The timing belt 53b wound between the small pulley 54b of the first-stage pulley 54 and the large pulley 55a of the second-stage pulley 55 allows the second-stage pulley 54 to move from the first-stage pulley 54 without generating noise or vibration. Driving force is transmitted to the eye pulley 55 in parallel. Moreover, since the diameter of the large pulley 55a of the second-stage pulley 55 is set to be very large compared to the diameter of the small pulley 54b of the first-stage pulley 54, the rotational speed of the first-stage pulley 54 is small pulley 54b. And the large pulley 55a are decelerated in accordance with the ratio of the diameters and transmitted to the second-stage pulley 55.

  Furthermore, a third-stage pulley 56 is fixed to the root portion of the rotating shaft 43 in which the first-stage pulley 54 is inserted. The timing belt 53c wound between the small pulley 55b of the second-stage pulley 55 and the large pulley 56a of the third-stage pulley 56 causes the third-stage pulley 55 to move from the third-stage pulley 55 without generating noise or vibration. A driving force is transmitted to the eye pulley 56 in parallel. Moreover, since the diameter of the large pulley 56a of the third-stage pulley 56 is set to be very large compared to the diameter of the small pulley 55b of the second-stage pulley 55, the rotational speed of the second-stage pulley 55 is small pulley 55b. Is further decelerated in accordance with the ratio of the diameters of the pulley and the large pulley 56 a and is transmitted to the third-stage pulley 56.

  Accordingly, the driving force of the tilt motor 51 is efficiently transmitted in parallel by the first-stage pulley 54, the second-stage pulley 55, and the third-stage pulley 56 at the third-stage deceleration, and the third-stage pulley 56 is fixedly attached. A large driving force can be obtained with respect to the rotating shaft 43. As a result, an accessory lens (not shown) is attached to the lens barrel 40 even if it is a high-performance large and heavy lens barrel 40 capable of shooting with HD image quality, resulting in increased load due to the eccentric center of gravity. However, a driving force sufficient to rotate the lens chassis 42 is exhibited, and the lens barrel 40 (lens 41) can be rotationally driven with a minimum driving angle in the tilt direction.

  Moreover, the first-stage pulley 54 and the third-stage pulley 56 (corresponding to the odd-number reduction members in the present invention) that are odd-numbered stages of deceleration are relative to the rotation shaft 43 of the lens chassis 42 that rotates the lens barrel 40. Since it is attached to be freely rotatable (first-stage pulley 54) or fixedly (third-stage pulley 56), the second-stage pulley 55 (corresponding to the even-number reduction member in the present invention), which is an even-numbered stage of deceleration. Although different from the rotation center axis (rotation axis 44), the first-stage pulley 54 and the third-stage pulley 56 rotate around the same rotation center axis (rotation axis 43). Therefore, even if the third-stage pulley 56 is added and the three-stage reduction method is adopted, a planar installation space for the third-stage pulley 56 is not required, and the three-stage reduction is performed with the same installation space as in the case of the two-stage reduction. Can be. As a result, space saving of the tilt rotation drive mechanism 50 can be achieved, and the video camera 10 can be downsized.

  Further, the first-stage pulley 54 has a higher rotational speed than the second-stage pulley 55 and the third-stage pulley 56, but the rotation shaft 43 rotates in the same direction as the first-stage pulley 54 by the third-stage pulley 56. The relative speed between the first-stage pulley 54 inserted into the rotation shaft 43 and the rotation shaft 43 is slower than that when the first-stage pulley 54 is rotated by another rotation center axis. As a result, wear of the sliding portion of the first-stage pulley 54 is reduced, and durability is improved.

By the way, the video camera 10 requires a large driving force not only for rotation in the tilt direction but also for rotation in the pan direction. That is, the rotation in the pan direction has a larger rotation angle and a higher rotation frequency than the tilt direction. In addition, the tilt rotation drive mechanism 50 only needs to rotate the lens barrel 40 and the lens chassis 42, whereas in the pan direction, the tilt chassis 31 and the tilt rotation drive mechanism 50 are added in addition to the lens barrel 40 and the lens chassis 42. Need to be rotated together. Furthermore, even if the rotation angle is large, the minimum drive angle must be small.
Therefore, the pan rotation driving mechanisms 60a and 60b (corresponding to the lens barrel rotation driving mechanism in the present invention) capable of obtaining a large driving force and a small minimum driving angle will be described in detail.

FIG. 4 is a perspective view showing one pan rotation drive mechanism 60a applicable to the video camera 10 of the present embodiment.
A pan rotation drive mechanism 60a shown in FIG. 4 can be disposed below the tilt chassis 31 in place of the pan rotation drive mechanism 70 (not equivalent to the lens barrel rotation drive mechanism in the present invention) shown in FIG. .

  As shown in FIG. 4, the pan rotation drive mechanism 60 a includes a pan motor 61, timing belts 63 a to 63 c, a first-stage pulley 64, a second-stage pulley 65, and a third-stage pulley 66. The pan motor 61 includes a drive shaft 61a, the first-stage pulley 64 includes a large pulley 64a and a small pulley 64b, and the second-stage pulley 65 includes a large pulley 65a and a small pulley 65b. The third-stage pulley 66 includes a large pulley 66a. The first-stage pulley 64, the second-stage pulley 65, and the third-stage pulley 66 correspond to the speed reducing member in the present invention.

  Here, the pan rotation drive mechanism 60a is installed so that the rotation center axes of the first-stage pulley 64 and the third-stage pulley 66 coincide with the vertical axis shown in FIG. Then, the timing belt 63 a is wound between the drive shaft 61 a of the pan motor 61 and the large pulley 64 a of the first-stage pulley 64. Therefore, the driving force of the pan motor 61 is transmitted in parallel to the first-stage pulley 64 without generating noise or vibration by the timing belt 63a. Moreover, since the diameter of the large pulley 64a of the first-stage pulley 64 is set to be very large compared to the diameter of the drive shaft 61a of the pan motor 61, the rotational speed of the pan motor 61 is between the drive shaft 61a and the large pulley 64a. It is decelerated according to the ratio of diameters and transmitted to the first stage pulley 64.

  Further, the large pulley 65a of the second-stage pulley 65 is installed as indicated by an arrow so as to hang the timing belt 63b that is wound around the small pulley 64b of the first-stage pulley 64. For this reason, the driving force is transmitted in parallel from the first-stage pulley 64 to the second-stage pulley 65 without generating noise or vibration by the timing belt 63b. Moreover, since the diameter of the large pulley 65a of the second-stage pulley 65 is set to be very large compared to the diameter of the small pulley 64b of the first-stage pulley 64, the rotational speed of the first-stage pulley 64 is small pulley 64b. And the large pulley 65a are decelerated in accordance with the ratio of the diameter to the second pulley 65a.

  Furthermore, a timing belt 63c is wound around the small pulley 65b of the second-stage pulley 65 and the large pulley 66a of the third-stage pulley 66 (corresponding to the final reduction member in the present invention). Therefore, the driving force is transmitted in parallel from the second-stage pulley 65 to the third-stage pulley 66 without generating noise or vibration by the timing belt 63c. In addition, since the diameter of the large pulley 66a of the third-stage pulley 66 is set to be very large compared to the diameter of the small pulley 65b of the second-stage pulley 65, the rotational speed of the second-stage pulley 65 is small pulley 65b. Is further decelerated according to the ratio of the diameters of the large pulley 66a and the large pulley 66a and is transmitted to the third-stage pulley 66.

  Therefore, the driving force of the pan motor 61 is efficiently transmitted by the first-stage pulley 64, the second-stage pulley 65, and the third-stage pulley 66 in parallel with a three-stage deceleration, and the third-stage pulley 66 has a sufficient driving force. The tilt chassis 31 shown in FIG. 2 is rotated in the pan direction. That is, the tilt chassis 31, the tilt rotation drive mechanism 50, the lens chassis 42, and the large and heavy lens barrel 40 can be rotationally driven in the pan direction at a small minimum drive angle.

  In addition, the first-stage pulley 64 and the third-stage pulley 66 (corresponding to the odd-number reduction members in the present invention) that are odd-numbered stages of deceleration rotate about the same rotation center axis. Therefore, even if the third-stage pulley 66 is added and the three-stage reduction method is adopted, a plane installation space for the third-stage pulley 66 is not required, and the three-stage reduction is performed with the same installation space as in the case of the two-stage reduction. Can be. As a result, space saving of the pan rotation drive mechanism 60a can be achieved, and the video camera 10 can be downsized.

FIG. 5 is a perspective view showing another pan rotation driving mechanism 60b applicable to the video camera 10 of the present embodiment.
The pan rotation drive mechanism 60b shown in FIG. 5 is replaced with the pan rotation drive mechanism 70 (not corresponding to the lens barrel rotation drive mechanism in the present invention) shown in FIG. 2 in the same manner as the pan rotation drive mechanism 60a shown in FIG. Thus, although it can be arranged at the lower part of the tilt chassis 31, the number of decelerating steps is increased as compared with the rotational drive mechanism 60a.

  As shown in FIG. 5, the pan rotation drive mechanism 60 b includes a pan motor 61, timing belts 63 a to 63 d, a first-stage pulley 64, a second-stage pulley 65, a third-stage pulley 66, and a fourth-stage pulley 67. ing. The pan motor 61 includes a drive shaft 61a, the first-stage pulley 64 includes a large pulley 64a and a small pulley 64b, and the second-stage pulley 65 includes a large pulley 65a and a small pulley 65b. The third-stage pulley 66 includes a large pulley 66a and a small pulley 66b, and the fourth-stage pulley 67 includes a large pulley 67a. The first-stage pulley 64, the second-stage pulley 65, the third-stage pulley 66, and the fourth-stage pulley 67 correspond to the reduction member in the present invention.

  Here, in the pan rotation drive mechanism 60b, the rotation center axes of the first-stage pulley 64 and the third-stage pulley 66 are the same, and the rotation center axes of the second-stage pulley 65 and the fourth-stage pulley 67 are shown in FIG. Installed to coincide with the vertical axis. A timing belt 63 a is wound around the drive shaft 61 a of the pan motor 61 and the large pulley 64 a of the first-stage pulley 64, and the large pulley 65 a of the second-stage pulley 65 is smaller than the first-stage pulley 64. It is installed as shown by the arrow so as to hang the timing belt 63b laid around the pulley 64b. A timing belt 63c is wound around the small pulley 65b of the second-stage pulley 65 and the large pulley 66a of the third-stage pulley 66, and the fourth-stage pulley 67 (corresponding to the final reduction member in the present invention). The large pulley 67a is installed as shown by an arrow so as to hang a timing belt 63d that is wound around the small pulley 66b of the third-stage pulley 66.

  Accordingly, the driving force of the pan motor 61 is paralleled by the first-stage pulley 64, the second-stage pulley 65, the third-stage pulley 66, and the fourth-stage pulley 67 without generating noise or vibration by the timing belts 63a to 63d. 2 is efficiently transmitted by the four-speed reduction, and the fourth-stage pulley 67 smoothly rotates the tilt chassis 31 and the like shown in FIG. 2 in the pan direction with a sufficient driving force. That is, the pan rotation drive mechanism 60b shown in FIG. 5 has one more reduction stage than the rotation drive mechanism 60a shown in FIG. 4, so that the lens barrel 40 can be smoothly moved in the pan direction with a smaller minimum drive angle. It can be rotated.

  In addition, the first-stage pulley 64 and the third-stage pulley 66 (corresponding to the odd-number reduction members in the present invention), which are odd-numbered stages of deceleration, rotate around the same rotation center axis, and the second-stage pulley 65 and the fourth-stage pulley 65 The eye pulley 67 (corresponding to the even speed reducing member in the present invention) rotates about the same rotation center axis. Therefore, even if the four-stage reduction method is used, the planar installation space is the same as in the case of the two-stage reduction. As a result, space saving of the pan rotation drive mechanism 60b can be achieved, and the video camera 10 can be downsized.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to embodiment mentioned above, For example, the following various deformation | transformation is possible.
(1) In the present embodiment, the conference room video camera 10 is taken as an example of a lens barrel rotation type imaging device. However, the imaging device is limited to the video camera 10 as long as the lens barrel 40 rotates. Absent. In addition, the video camera 10 of the present embodiment can rotate in both the tilt direction and the pan direction. However, if the video camera 10 can rotate in either the tilt direction or the pan direction, the tilt rotation drive mechanism 50 or the pan rotation drive is possible. Mechanisms 60a and 60b can be applied.

  (2) In this embodiment, the tilt rotation drive mechanism 50 and the pan rotation drive mechanism 60a are set to three-stage deceleration, and the pan rotation drive mechanism 60b is set to four-stage deceleration. it can. Further, instead of transmitting the driving force in parallel by the timing belt 53 or the like, a spur gear may be combined.

It is a perspective view which shows the video camera of this embodiment. It is a perspective view which shows the internal structure of the video camera of this embodiment. It is a perspective view which shows the tilt rotation drive mechanism in the video camera of this embodiment. It is a perspective view which shows one pan rotation drive mechanism applicable to the video camera of this embodiment. It is a perspective view which shows the other pan rotation drive mechanism applicable to the video camera of this embodiment.

Explanation of symbols

10. Video camera (Lens barrel rotating imaging device)
31 Tilt chassis 40 Lens barrel 41 Lens 43 Rotation axis (Rotation center axis)
44 Rotation axis (Rotation center axis)
50 Tilt rotation drive mechanism (lens barrel rotation drive mechanism)
51 Tilt motor (drive source)
53, 53a, 53b, 53c Timing belt 54 First stage pulley (deceleration member)
54a Large pulley 54b Small pulley 55 Second-stage pulley (reduction member)
55a Large pulley 55b Small pulley 56 3rd stage pulley (reduction member)
56a Large pulleys 60a, 60b Pan rotation drive mechanism (lens barrel rotation drive mechanism)
61 Pan motor (drive source)
63a, 63b, 63c, 63d Timing belt 64 First stage pulley (deceleration member)
64a Large pulley 64b Small pulley 65 Second stage pulley (reduction member)
65a Large pulley 65b Small pulley 66 3rd stage pulley (reduction member)
66a Large pulley 66b Small pulley 67 Fourth-stage pulley (reduction member)
67a Large pulley

Claims (6)

A lens barrel rotation drive mechanism for rotating a lens barrel to which an imaging lens is attached in a horizontal direction or a vertical direction,
A driving source that exerts a driving force to rotate the lens barrel;
Three or more speed reducing members for transmitting the driving force in parallel while reducing the driving speed of the driving source,
An odd speed reduction member that is an odd speed reduction stage and an even speed reduction speed reduction member that is an even speed reduction speed in each of the speed reduction members rotate around different rotation center axes,
Each of the odd-number reduction members rotates around the same rotation center axis. In the lens barrel rotation driving mechanism according to claim 1,
Comprising four or more deceleration members,
Each of the even speed reducing members rotates around the same rotation center axis. In the lens barrel rotation driving mechanism according to claim 1,
A plurality of timing belts for transmitting the driving force of the driving source;
The final deceleration member, which is the final stage of deceleration among each of the deceleration members, includes a large pulley that receives the driving force transmitted from the timing belt that is wound around the deceleration member of the preceding stage,
The other deceleration members other than the final deceleration member include a large pulley that receives a driving force transmitted from the timing belt that is wound around the deceleration member or the drive source in the immediately preceding stage, and a downstream element in the downstream. A lens barrel rotation driving mechanism, comprising: a small pulley that transmits a driving force to the timing belt that is wound around the deceleration member. In the lens barrel rotation driving mechanism according to claim 1,
One of each of the odd speed reducing members or each of the even speed reducing members rotates about the same rotation center axis as the rotation axis for rotating the lens barrel. In the lens barrel rotation driving mechanism according to claim 1,
One of the odd speed reducing members or each of the even speed reducing members including the final speed reducing member rotates around the same rotation center axis as the rotation axis for rotating the lens barrel,
The final deceleration member is fixedly attached to the rotating shaft;
The speed reduction member that rotates about the same rotation center axis as the rotation shaft among the speed reduction members other than the final speed reduction member is rotatably attached to the rotation shaft. Lens barrel rotation drive mechanism. A lens barrel to which an imaging lens is attached;
A lens barrel rotation type imaging device comprising: a lens barrel rotation drive mechanism for rotating the lens barrel in a horizontal direction or a vertical direction;
The lens barrel rotation drive mechanism is
A driving source that exerts a driving force to rotate the lens barrel;
Three or more speed reducing members for transmitting the driving force in parallel while reducing the driving speed of the driving source,
An odd speed reduction member that is an odd speed reduction stage and an even speed reduction speed reduction member that is an even speed reduction speed in each of the speed reduction members rotate around different rotation center axes,
Each of the odd speed reducing members rotates around the same rotation center axis.

Images