JP2007293025A - Rotational load device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation load device capable of surely reducing the variation in the angular moment in the tilt direction and vibration caused by the backlash of a gear in the vicinity of changeover tilt angle, and surely making a unit part rotate by a driving source. <P>SOLUTION: A camera cradle is equipped with a part integrally rotating with shafts 15a and 15b as the center of rotation, when a camera 6 is mounted on a receiving part 15 (hereinafter, to be referred to as a unit part); a cam 28 press-fit in the shaft 15b; and a friction pad 30, made to press-contact with the outer circumferential surface of the lower part of the cam 28 by a spring 31. The cam 28 is fixed, at a position where a position vector (r) toward the center of gravity G of the unit part from the shaft 15b becomes substantially parallel to the center-of-gravity direction, when the vertex 28a of its projecting part comes into contact with the center of the friction pad 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary load device, and more particularly, to a rotary load device that controls rotation and stop when a center of gravity of a rotating object and a rotation center in a tilt direction are greatly deviated.

  2. Description of the Related Art Conventionally, there has been known a monitoring camera technique in which a camera is installed on a pan head attached to a wall surface and the pan head is rotated by a motor in a tilt direction (see, for example, Patent Documents 1 and 2). In addition, a technique for converting the camera into a digital camera is also known (see, for example, Patent Document 3).

  Here, when the digital camera is mounted on the pan head receiving portion, the portion that rotates together in the tilt direction (hereinafter referred to as “unit portion”) has a center of gravity above the center of rotation. Often, they are far apart.

  For this reason, the rotational moment when the unit portion is rotated in the tilt direction varies greatly depending on the load (hereinafter referred to as “self-weight load”) generated by the weight of the digital camera mounted on the pan head. At this time, there is a problem that vibration caused by gear backlash or the like is generated, and an image captured by the digital camera is blurred.

Therefore, conventionally, a constant friction load (hereinafter referred to as “friction”) around the rotation axis of the unit portion is used to reduce fluctuations in the rotational moment of the unit portion and to reduce vibration due to gear backlash and the like. Has been added.
No. 2-4319 JP 2002-40553 A JP 2003-60937 A

  However, the rotational moment of the unit part during tilt rotation is not constant. In addition, since the direction of the backlash of the gear is switched at the tilt angle (hereinafter referred to as “switching tilt angle”) when the magnitude of the self-weight load is switched from minus to plus or from plus to minus, the unit portion is Vibrates most.

  However, if a large amount of friction is applied to minimize the vibration caused by the gear backlash at the switching tilt angle, the motor torque of the drive source is increased when the rotational moment is large, for example, when the unit part is lifted from a large tilted state. It becomes impossible to rotate due to lack of. On the other hand, if friction is applied only to such an extent that rotation by the motor torque of the drive source can be surely performed, the image will be blurred due to fluctuations in rotational moment and vibration due to gear backlash, and the original effect cannot be obtained. .

  An object of the present invention is to provide a rotational load capable of reliably reducing vibrations caused by fluctuations in rotational moment in the tilt direction and gear backlash before and after the switching tilt angle, and capable of reliably rotating the unit portion by a drive source. To provide an apparatus.

  In order to achieve the above object, the rotary load device according to claim 1 is a rotary load device provided in a unit rotary device that uses a drive source to rotationally drive the unit portion around its rotation center in a tilt direction, In the rotary load device that applies a load to the unit unit that impedes the rotational drive, the load is maximized when the direction of the position vector from the rotation center of the unit unit toward the center of gravity is substantially parallel to the direction of gravity. It has the control mechanism which controls.

  According to the present invention, when the direction of the position vector from the rotation center of the unit portion toward the center of gravity is substantially parallel to the gravity direction, the unit portion is rotationally driven around the rotation center in the tilt direction using the drive source. Control to maximize the load applied to the unit part, vibrations due to rotational moment fluctuation in the tilt direction and gear backlash before and after the switching tilt angle can be reliably reduced, and the drive part can Can be reliably rotated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of a camera cradle head device (hereinafter referred to as “camera cradle”) equipped with a camera as a rotational load device according to a first embodiment of the present invention. When viewed from the left diagonal front, (b) shows the case viewed from the right diagonal rear. Here, in order to facilitate explanation of the structure of the camera cradle shown in FIG. 1, a part of the cover is removed.

  In FIG. 1, a camera cradle 10 is a device on which a digital camera 6 (hereinafter referred to as “camera 6”) is mounted so as to be capable of pan rotation and tilt rotation. The camera cradle 10 has a pedestal portion 1 covered with a pedestal cover 17 at the bottom of the apparatus, a card slot 7 having a memory card 2 insertion portion at the front of the pedestal portion 1, and a rear portion of the pedestal portion 1. And a card slot 8 having an insertion portion for the wireless run card 4. The camera cradle 10 includes a power connector 3, a USB connector 5, a pan cover 12 fixed to the chassis 16, an adapter 14 that mechanically and electrically connects the camera 6 at its side surface, and a camera. 6 and a receiving portion 15 that receives 6 at its bottom.

  The camera 6 includes a liquid crystal screen 6-a that displays image data, and a lens unit 6b that images a subject. The adapter 14 is electrically connected to a connector (not shown) provided on the receiving portion 15 at the bottom. With such a configuration, the data photographed by the camera 6 can be stored in the memory card 2 inserted in the card slot 7, and conversely, the data in the memory card 2 is transferred to the digital camera 6 and the liquid crystal screen 6 of the digital camera. -A can also be displayed.

  When the wireless run card 4 is inserted in the card slot 8, the camera cradle 10 is connected to the network via an access point (not shown).

  2 is a perspective view of the camera cradle 10 of FIG. 1 with the exterior cover removed, wherein (a) is a front view, (b) is a left side view, and (c) is a plan view viewed from directly above. Indicates. Here, in the camera cradle shown in FIG. 2, in order to facilitate the explanation of the pan rotation operation, electric parts such as a printed circuit board are omitted and the mechanical part is mainly shown.

  In FIG. 2, the camera cradle 10 includes a motor support plate 33 fixed to a base plate 34 with screws via a plurality of rubber bushes 35, and a pan motor 37 for driving a pan mechanism section fixed to the motor support plate 33. With. The camera cradle 10 includes a bevel gear 38 that is press-fitted into the pan motor 37, a bevel gear 40 that meshes with the bevel gear 38, and a chassis 16 that fixes the pan shaft 41 that is coaxial with the bevel gear 40. Is provided.

  The pan shaft 41 is rotatably inserted into a pan bearing 36 fixed to the motor support plate 33, and is restricted in the thrust direction by an E ring 39.

  The chassis 16 has side plates 16a and 16b on both sides thereof, and bearings 20a and 20b are press-fitted therein. As a result, the chassis 16 rotates around the pan shaft 41 in synchronization with the rotation of the pan motor 37. In the present embodiment, the chassis 16 can be rotated 160 ° clockwise and counterclockwise from the state shown in FIG.

  The receiving portion 15 has shafts 15a and 15b coaxially provided on both left and right side surfaces thereof, and the shafts 15a and 15b are rotatably inserted into the bearings 20a and 20b.

  A tilt motor 21 (hereinafter referred to as “motor 21”) for driving the tilt mechanism section is fixed to the side plate 16a.

  As shown in FIG. 2C, the tilt motor 21 has an output shaft 21a into which a gear 22 is press-fitted. Further, the side plate 16a fixes the shaft 23 into which the gear 25 that receives the restriction in the thrust direction by the E-ring 24 (see FIG. 1B) is inserted.

  The gear 25 (FIG. 2C) is composed of large and small gears 25a and 25b which are coaxially formed integrally. Here, the gear 25a meshes with the gear 22, and the gear 25b meshes with the partial gear 26 press-fitted into the shaft 15a. As a result, the receiving portion 15 rotates around the shafts 15a and 15b in synchronization with the rotation of the motor 21. In the present embodiment, the camera cradle 10 can be rotated 40 ° clockwise as shown in FIG. 3A from the state of FIG. Can rotate 40 ° clockwise.

  The shaft 15b (FIG. 2B) is press-fitted with a cam 28, and a friction pad 30 is in contact with the lower outer peripheral surface of the cam 28. A plate spring 31 is bonded to the bottom of the friction pad 30, and the plate spring 31 is fixed to the chassis 16.

  The friction pad 30 receives a force in the direction of the arrow Z (FIG. 2A) by the leaf spring 31, whereby the friction pad 30 is pressed against the outer peripheral surface of the cam 28. Here, conventionally, when the camera 6 is mounted on the receiving portion 15, the fluctuation of the rotational moment of the portion (hereinafter referred to as “unit portion”) that rotates integrally with the shafts 15 a and 15 b as the rotation center is: It is known that the load caused by the weight of the camera 6 varies most greatly in the tilt angle (hereinafter referred to as “switching tilt angle”) when switching from minus to plus or from plus to minus. That is, when the direction of the position vector r from the shaft 15b toward the center of gravity G of the unit portion and the direction of gravity (one-dot chain line) are substantially parallel, the fluctuation of the rotational moment of the unit portion is the largest. Further, the vibration due to the gear backlash increases before and after the switching tilt angle.

  Therefore, as shown in FIG. 2B, the cam 28 has a position of the convex portion 28a (surface with the largest radius of the cam 28) in contact with the center of the friction pad 30 and the position vector r. Are fixed at positions where they are substantially parallel. As a result, when the tilt angle becomes the switching tilt angle, the magnitude of the friction that the cam 28 receives from the friction pad 30 is maximized, and the fluctuation of the rotational moment in the tilt direction can be reliably reduced. Vibration due to gear backlash can also be reduced. Further, when the tilt angle deviates from the switching tilt angle, the magnitude of the friction becomes small, so that the unit portion can be reliably rotated by the motor 21.

  On the other hand, as shown in FIGS. 3A and 3B, the friction pad 30 is in contact with the surfaces 28b and 28c having the smallest radius of the cam 28 in a state where the unit portion is at the most inclined position in the tilt direction. It has become. With such a configuration, the friction that the cam 28 receives from the friction pad 30 in the state shown in FIGS. 3A and 3B can be minimized. Thereby, it is possible to prevent the motor unit 21 from rotating and stopping due to insufficient motor torque of the motor 21 in the state shown in FIGS.

  Further, the radius of the cam 28 gradually contacts the center of the friction pad 30 from the state shown in FIG. 2B to the state shown in FIG. 3A or 3B gradually decreases. It has a shape. Thereby, as the angle formed by the position vector r and the direction of gravity increases, the friction that the cam 28 receives from the friction pad 30 can be reduced, and the tilt rotation can be performed smoothly.

  Further, if the user can rotate the cam 28 about the shaft 15b and can be fixed at an arbitrary fixing position, a camera (camera 61) other than the camera 6 can be mounted on the receiving portion 15 in a replaceable manner. it can.

  In this case, the fixed portion is determined according to the center of gravity of the unit portion when a camera that can be mounted on the camera cradle 10 is mounted on the cam 28 and the shaft 15b.

  Hereinafter, a case where a camera 61 whose lens portion 61a is larger than the lens portion 6b is mounted on the receiving portion 15 in place of the camera 6 with the cam 28 fixed in the state of FIG. .

  In the unit part with the camera 61 mounted, the center of gravity G of the unit part shifts in the direction of the lens part 61a as shown in FIG. 4 due to the weight of the lens part 61a. For this reason, the direction of the position vector r from the shaft 15b toward the center of gravity G of the unit portion is inclined by about 5 ° counterclockwise with respect to the direction of gravity (dashed line).

  Therefore, the cam 28 is fixed in a state rotated clockwise by 5 ° from the state shown in FIG. Thereby, even when the camera 61 is mounted on the receiving portion 15, the effects of the present invention can be achieved.

  Further, the cam 28 and the shaft 15b are preliminarily attached to each camera on which the mark indicating the fixed portion is mounted. Thus, the present invention can be reliably achieved by simply aligning the cam 28 and the shaft 15b with one of the marks attached to the cam 28 and the shaft 15b in accordance with the camera mounted on the receiving portion 15 and fixing the cam 28. The effect of can be produced.

  FIG. 5 is a view showing another modification of the camera cradle 10 shown in FIG.

  The camera cradle 10a in FIG. 5 is basically the same in configuration as the camera cradle 10, and the same components are denoted by the same reference numerals and redundant description is omitted, and different components will be described below. .

  In the camera cradle 10a of FIG. 5, a disc-shaped friction plate 51 is press-fitted into the shaft 15b at the center of the circle instead of the cam 28. The friction pad 30 is pressed against the lower outer peripheral surface of the friction plate 51 by a spring 31 and applies friction to the rotation of the receiving portion 15 around the shaft 15b.

  Since the friction plate 15 has a concentric shape with the shaft 15b, even if the digital camera 6 is tilted in the tilt direction, the force of the spring 31 pressing against the friction plate 51 of the friction pad 30 is constant.

  6A and 6B are diagrams used to explain the friction plate 51 in FIG. 5, where FIG. 6A is a plan view viewed from below, and FIG. 6B is a perspective view viewed obliquely from below.

  In FIG. 6, the surface state of the outer peripheral surface that contacts the friction pad 30 of the friction plate 51 is not uniform, and the high friction region 51b has a higher friction coefficient than the low friction region 51a. Further, as shown in FIG. 5, the friction plate 51 has a position vector r from the shaft 15b toward the center of gravity G of the unit portion when the portion 51c having the highest ratio of the high friction region 51b contacts the center of the friction pad 30. It is fixed at a position where the direction of gravity is almost parallel. Thereby, when the tilt angle becomes the switching tilt angle, the friction plate 51 receives the maximum amount of friction from the friction pad 30, and the fluctuation of the rotational moment in the tilt direction can be surely reduced. Vibration caused by backlash of the front and rear gears can be reduced. Further, when the tilt angle deviates from the switching tilt angle, the magnitude of the friction becomes small, so that the unit portion can be reliably rotated by the motor 21.

  Further, as shown in FIG. 6B, the friction plate 51 has a shape in which the ratio of the high friction region 51 b in the portion in contact with the center of the friction pad 30 is reduced. Thereby, as the angle formed by the position vector r and the direction of gravity increases, the friction received by the friction plate 51 from the friction pad 30 can be reduced, and the tilt rotation can be performed smoothly.

  In the present embodiment, the friction pad 30 is in contact with the outer peripheral surface of the friction plate 51 to obtain friction. However, the present invention is not limited to this as long as the friction that the friction plate 51 receives from the friction pad 30 decreases as the angle between the position vector r and the direction of gravity increases. For example, the friction pad 30 may have a shape in contact with the flat surface portion 51d of the friction plate 51, and the friction may be obtained by changing the friction coefficient of the flat surface portion 51d.

  Further, similarly to the camera cradle 10, if the user can rotate the friction plate 51 around the shaft 15b and can be fixed at an arbitrary fixing position, the camera (camera 61) other than the camera 6 is replaced with the receiving portion 15. It can be mounted as possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a camera cradle-type pan head device (hereinafter referred to as “camera cradle”) equipped with a camera as a rotational load device according to a first embodiment of the present invention. When viewed, (b) shows the case viewed from the right rear side. It is a perspective view in the state where the exterior cover of the camera cradle of Drawing 1 was removed, (a) is a front view, (b) is a left view, (c) shows a top view seen from right above. It is a figure which shows the state which tilted the camera cradle, (a) shows the state rotated 40 degrees clockwise from the state of FIG.2 (b), (b) shows the timepiece from the state of FIG.2 (b). The state rotated 40 degrees in the direction is shown. It is a figure which shows the modification of the camera cradle of FIG.2 (b). It is a figure which shows the other modification of the camera cradle shown in FIG.2 (b). It is a figure used for demonstrating the friction board in FIG. 5, (a) is the top view seen from the bottom, (b) is the perspective view seen from diagonally downward.

Explanation of symbols

6 Camera 10 Camera cradle 15 Receiving part 15a, 15b Shaft 21 Motor 28 Cam 30 Friction pad 31 Leaf spring 51 Friction plate

Claims (11)

A rotary load device provided in a unit rotation device that drives a unit portion to rotate in a tilt direction around a rotation center using a drive source, wherein the load unit that impedes the rotation drive is applied to the unit portion.
The rotary load device having a control mechanism for controlling the load to become maximum when the direction of a position vector from the rotation center of the unit portion toward the center of gravity is substantially parallel to the direction of gravity.   The rotary load device according to claim 1, wherein the control mechanism controls the load to decrease as the angle formed by the direction of the position vector and the direction of gravity increases.   The control mechanism includes a cam provided coaxially with the rotation center of the unit portion, and a friction pad pressed against the lower outer peripheral surface of the cam, and a portion where the radius of the cam is pressed by the friction pad The rotational load device according to claim 1, wherein the load is increased by making the maximum value of the rotation load. The unit portion includes a first unit including the rotation center, and a second unit attached to the first unit,
4. The rotary load device according to claim 3, wherein the control mechanism rotates and fixes the cam in the tilt direction according to the position of the center of gravity when the second unit is mounted.   The rotary load device according to claim 5, wherein the second unit is any one of a plurality of devices that are replaceably attached to the first unit.   The rotary load device according to claim 4 or 5, wherein the first unit is a cradle, and the second unit is an imaging device.   The control mechanism includes a disk-shaped rotating plate provided coaxially with the rotation center of the unit portion, and a friction pad pressed against the lower outer peripheral surface of the rotating plate, and a portion pressed by the friction pad The rotary load device according to claim 1, wherein the load is increased by increasing a friction coefficient of the rotary plate.   The control mechanism includes a disc-shaped rotary plate provided coaxially with the rotation center of the unit portion, and a pressure contact portion that presses a friction pad against a part of a flat portion of the rotary plate, and the friction pad The rotary load device according to claim 1, wherein the load is increased by increasing a friction coefficient of the rotary plate in a portion to be pressed. The unit portion includes a first unit including the rotation center, and a second unit attached to the first unit,
The rotational load according to claim 7 or 8, wherein the control mechanism rotates and fixes the rotary plate in the tilt direction according to the position of the center of gravity when the second unit is mounted. apparatus.   The rotary load device according to claim 9, wherein the second unit is any one of a plurality of devices that are replaceably attached to the first unit.   The rotary load device according to claim 9 or 10, wherein the first unit is a cradle, and the second unit is an imaging device.

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