JP2011107334A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve assembling workability when a cover member is fastened and fixed to a mounting frame with a screw. <P>SOLUTION: A mounting frame (62) that forms a housing (case) of a lens drive device is provided with a projection (86) having a female screw (87). A positioning recess (88) in which the projection (86) is fitted is formed in the rear face of the screw fastening portion of the cover member (79). In addition, a screw receiving recess (83) for receiving the head of a fixing screw (81) is formed in the opposite face of the positioning recess (88) of the cover member (79). A through-hole for the fixing screw (81) is formed through the screw receiving recess (83) and positioning recess (88), which is in the opposite direction to the recess (83). The fixing screw (81) is inserted from the screw receiving recess (83) and it is fastened to a male screw (87), thereby fixing the cover member (79) to a mounting frame (62). A hollow in the screw receiving recess (83) prevents the fixing screw (81) from falling during mounting of the cover member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lens driving device, and more particularly to a structure suitable for mounting a cover member in a driving device (drive unit) installed on a side portion of a lens barrel and a lens driving device to which the structure is applied.

  A television camera for broadcasting or business use includes a camera body on which an imaging device, a video processing circuit, and the like are mounted, and a lens device that includes an optical system that forms a subject image on an imaging surface of the imaging device. A lens device (for example, a product group called “portable lens”) for a portable television camera used for coverage or the like generally has a lens barrel and a drive unit installed on the side of the lens barrel. (See Patent Document 1).

  The lens barrel holds various lenses constituting the optical system inside, and a mount that is detachably attached to the camera body by, for example, a bayonet method is provided at the rear end portion. An operation ring such as a focus ring, zoom ring, and iris ring is rotatably provided on the outer periphery of the lens barrel. By rotating the operation ring, the optical system can be adjusted, for example, focus adjustment, zooming, iris adjustment. Is done.

  The drive unit incorporates a drive mechanism section for rotating the operation ring, a circuit board, and the like inside the housing (case), and operation sections such as a zoom seesaw switch and a recording switch are provided on the outer surface of the case. . The drive mechanism unit includes a motor that generates a driving force, a connection gear that meshes with a tooth row formed on the peripheral surface of the operation ring, a gear train that transmits the driving force of the motor to the connection gear, and the like. A part of the connecting gear is exposed through an opening (gear opening) formed on the side surface of the case, and meshes with a tooth row of the operation ring. On the circuit board disposed in the case, a drive control circuit for controlling the drive of the drive mechanism unit based on an operation signal from the operation unit, a control signal from the camera body, and the like are mounted.

JP 2007-298672 A

  This type of lens device is used in various environments, and may be used in situations where it is splashed with water such as outdoors in rainy weather. Water or dust can enter the case of the drive unit from the opening that exposes the connecting gear, and water droplets can be scattered inside the case by the rotation of the gears and adhere to the circuit board, causing short circuits and wiring deterioration. obtain. In addition, the motor of the drive mechanism unit becomes a source of electrical noise and may adversely affect the circuit on the circuit board.

  In response to this problem, the inventor of the present application devised a configuration in which a cover member having an effect of preventing water wetting of the circuit board and electromagnetic shielding is arranged in the case of the drive unit (Japanese Patent Application No. 2008-313971). In order to fix the screw to the case (mounting frame), the structure that facilitates the positioning and screwing work of the members was examined.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a cover member mounting structure capable of improving assembly workability, and to provide a lens driving device to which the mounting structure is applied. .

  In order to achieve the above object, the following invention modes are provided.

  (Invention 1): A lens driving device according to Invention 1 is attached to a side of a lens barrel holding an optical system, and rotates a rotatable operation ring provided on an outer periphery of the lens barrel to rotate the optical system. In a lens driving device for adjusting the system, a driving mechanism unit including a coupling gear that engages with the operation ring, a motor that rotates the coupling gear, a circuit board on which a circuit that controls the driving mechanism unit is mounted, A gear opening that exposes the connection gear on the side surface of the case on the lens barrel side, and a case in which the drive mechanism unit and the substrate are arranged in order from the lens barrel side; A cover member disposed between the drive mechanism portion and the circuit board, the case as a mounting frame, a female screw portion formed in the mounting frame, and a through hole formed in the cover member And A mounting structure for a cover member for fixing the cover member to the mounting frame by tightening a fixing screw inserted through the through hole and tightening the female screw portion, and the mounting frame includes the female screw portion. A first recess is formed on the surface of the cover member on the mounting frame side, and the first recess of the cover member is opposite to the first recess. A second recess for receiving the head of the fixing screw is formed, and the through hole is formed through the second recess and the first recess opposite to the second recess, and the protrusion includes the cover member. The mounting structure for fitting the first recess to align the positions of the female screw portion and the through hole, inserting the fixing screw from the second concave portion side, and tightening the fixing screw to the female screw portion Is adopted The features.

  According to the present invention, the portion for tightening the fixing screw (screw receiving portion) is configured in a concave shape (second concave portion), so that the fixing screw can be prevented from dropping during assembly. In addition, a reverse concave shape (first concave portion) is provided on the back surface of the concave shape (second concave portion), and a structure that is fitted with a protruding portion (boss having a female screw portion) protruding from the mounting frame, Positioning is performed when the cover member is attached.

  By using the screw tightening portion where the mounting frame and the cover member are in contact as positioning means at the time of mounting, it is not necessary to separately provide positioning means at other locations, and the configuration can be simplified.

  There are various types of components of the optical system included in the lens barrel. For example, in the case of a lens device for a television camera, a focus lens, a variable power lens, an iris (iris) mechanism, a master lens, and the like. Can be included. An object to be driven by the lens driving device (driving unit) is a lens movably supported in the lens barrel (for example, at least one of a focus lens, a variable power lens, and a master lens, preferably a plurality of lenses). A diaphragm can also be included.

  The cover member according to the first aspect of the present invention can have a protective cover function that prevents water and dust that have entered the case from the gear opening from adhering to the circuit board. Further, a mode in which the cover member has a function of shielding electrical noise is also possible.

  Further, the cover member can be formed into a shape such as a motor or a gear train along a complicated uneven shape exposed on the circuit board side of the drive mechanism unit. For example, a cover member having such a complicated shape and first and second recesses can be manufactured by integral molding of resin.

  (Invention 2): The lens driving device according to Invention 2 is characterized in that, in Invention 1, the depth of the second recess is not less than ½ of the total length of the fixing screw.

  By making the walls constituting the second recesses (walls standing around the through holes) somewhat high, it is possible to effectively prevent the fixing screws from falling. If the depth of the fixing screw is 1/2 or more of the total length (the length from the tip of the male screw to the tip of the head), the fixing screw that has fallen in the second recess is retained in the second recess. be able to.

  (Invention 3) In the lens driving device according to Invention 3, in the invention 1 or 2, the size of the screw receiving surface for receiving the head of the fixing screw inside the second recess is the female screw portion. It is equal to or larger than the size of the upper end surface of the protruding portion.

  An area that is sufficiently wider than the diameter of the head of the fixing screw is used as a screw receiving surface, and the screw receiving surface is surrounded by a wall to form the second recess, thereby fixing the fixing screw that has fallen in the second recess. Can be effectively prevented from falling.

  (Invention 4): In the lens driving device according to Invention 4, in any one of Inventions 1 to 3, the protrusion is cylindrical, and the female screw portion is formed on an upper end surface of the protrusion. It is characterized by.

  The shape of the protrusion provided on the mounting frame can be a prismatic shape, a cylindrical shape, or the like. Since the upper end surfaces of these protrusions (surfaces where the female screw portions are opened) serve as connecting surfaces for screwing the cover member, it is desirable that the periphery of the upper end surface be a flat surface.

  (Invention 5): A lens driving device according to Invention 5, in any one of Inventions 1 to 4, wherein the cover member has a shape covering at least a range facing the gear opening and the gear train of the driving mechanism section. It is characterized by having.

  According to this aspect, when gears such as the connecting gear rotate, it is possible to effectively prevent water scattering and dust scattering from the drive mechanism unit side to the circuit board.

  (Invention 6): A lens driving device according to Invention 6, according to any one of Inventions 1 to 5, wherein the case includes a first frame that forms a first side surface portion facing the lens barrel side, and And a second frame that is connected to the first frame and forms an outer second side surface far from the lens barrel opposite to the first side surface.

  According to this aspect, it is easy to attach the lens driving device to the lens barrel, and it is easy to attach an electric drive mechanism or the like housed in the case of the lens driving device.

  (Invention 7): The lens driving device according to Invention 7 is characterized in that, in Invention 6, the first frame is used as the attachment frame, and the cover member is fixed to the first frame by the fixing screw. And

  According to this aspect, after the drive mechanism is assembled to the first frame, the first frame is assembled to the side of the lens barrel, and the engagement state between the connecting gear and the operation ring of the lens barrel is confirmed. It is possible to attach the cover member afterwards.

  When fixing the cover member in such an assembly process, if the fixing screw is dropped, it is difficult to handle the assembly target including the lens barrel, and the dropped fixing screw is taken out. This is a very troublesome task. In this regard, according to the present invention, it is possible to prevent the fixing screw from dropping by the second recess, and the assembly workability is improved.

  According to the present invention, positioning when attaching the cover member to the attachment frame is easy, and the fixing screw can be prevented from dropping at the time of attachment. This facilitates assembly work.

The perspective view which showed the whole lens apparatus which concerns on embodiment of this invention The figure which showed a mode that looked up at the lens apparatus of this example from back diagonally downward Exploded perspective view showing the internal structure of the drive unit A perspective view showing the inside of the housing with the protective cover assembled Partial enlarged view of FIG. Exploded perspective view of screw tightening part Sectional view of screw tightening part Perspective view of screw tightening part The perspective view of the drive unit in the state removed from the lens barrel

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

<Overall configuration of lens device>
FIG. 1 is a perspective view showing an entire lens apparatus according to an embodiment of the present invention. FIG. 1 shows a state in which the lens device is looked down obliquely from the upper front. FIG. 2 is a view showing a state in which the lens device is looked up obliquely from below and rearward. The lens apparatus 10 shown in these drawings is a lens apparatus that is mounted on a broadcast or commercial television camera (video camera) that is mainly carried by a news gathering or the like, and is a “portable lens” or “handy type lens”. ”,“ ENG lens ”and the like.

  As illustrated, the lens device 10 includes a lens barrel 12 and a drive unit 14 (corresponding to a “lens drive device”) installed on the side of the lens barrel 12. The lens barrel 12 has a bayonet-type mount portion 20 at the rear end, and the lens barrel 12 is attached to the camera body by engaging the mount portion 20 with a mount portion of a camera body (not shown). A TV camera is configured by being attached to the main body.

  As is well known, the lens barrel 12 houses a lens and a diaphragm that constitute an optical system for forming a subject image, and a mirror that supports various components of the lens barrel 12 as a lens. In addition to the lens fixed to the trunk body, a focus lens group, a variable power lens group, and a master lens group supported so as to be movable in the optical axis direction are arranged.

  Various forms are possible for the type and number of lenses constituting the optical system, the structure of the diaphragm, the order of arrangement, and the relative positional relationship. As an example, a rear focus type zoom lens apparatus will be described. In order from the objective side, five lens groups of a fixed lens, a variable power lens, a front master lens, a focus lens, and a rear master lens are arranged. An iris diaphragm is arranged immediately before.

  On the outer periphery of the lens barrel 12 (lens barrel main body), a plurality of operation rings (21 to 26) that can rotate with respect to the barrel main body are provided. In the case of this example, focus rings 21 and 22 from the front side (object side), a zoom ring 24 connected to the variable power lens group, and an iris ring 26 connected to the stop are arranged as operation rings. When the focus rings 21 and 22 are rotated, the focus lens group is moved in the optical axis direction in conjunction with the rotation, so that the focal position (the subject distance in focus) of the entire optical system is changed.

  When the zoom ring 24 is rotated, the zoom lens group is moved in the optical axis direction in conjunction with the zoom ring 24 to change the focal length of the entire optical system. When the iris ring 26 is rotated, the diaphragm is linked with this. The aperture value of the entire optical system is changed by opening and closing.

  Gear teeth 21A, 22A, 24A, and 26A are formed on the outer peripheral surfaces of the first focus ring 21, the second focus ring 22, the zoom ring 24, and the iris ring 26, respectively. The gear teeth 21 </ b> A, 22 </ b> A, 24 </ b> A, 26 </ b> A of these operation rings are meshed with corresponding connecting gears provided on the drive unit 14 (connecting gears of a driving mechanism provided corresponding to the driving target).

  The rotation range of the first focus ring 21 is not restricted, and the first focus ring 21 can be rotated endlessly and is slidable in the optical axis direction (front-rear direction). On the other hand, the rotation range of the second focus ring 22 is restricted by a stopper member (not shown). For example, the second focus ring 22 is restricted so that it can rotate within a range of about 120 degrees.

  When the first focus ring 21 is set to the rear specified position in the optical axis direction, the first focus ring 21 and the second focus ring 22 are connected, and the first focus ring 21 and the second focus ring 22 are integrated. To turn. When the first focus ring 21 is rotated in this state, the first focus ring 21 can be rotated only within the rotatable range of the second focus ring 22.

  On the other hand, when the first focus ring 21 is set to the front specified position, the connection between the first focus ring 21 and the second focus ring 22 is released. As a result, the first focus ring 21 can be rotated endlessly.

  Such a configuration of the focus rings (21, 22) is to switch between a focus operation of the relative position instruction method and a focus operation of the absolute position instruction method by the slide movement (position in the optical axis direction) of the first focus ring 21. This is a means disclosed in Japanese Patent Application Laid-Open No. 2007-178633. When the first focus ring 21 is set at the front specified position, the focus operation is a relative position indicating method. When the first focus ring 21 is set at the rear specified position, the rotation range is restricted. Focus operation.

  A first fixed ring 28 and a second fixed ring 30 that are fixed to the lens barrel body are provided on the outer peripheral portion of the lens barrel 12. The first fixed ring 28 is disposed between the focus ring 22 and the zoom ring 24 and is integrally formed with the lens barrel body. The second fixed ring 30 is disposed between the zoom ring 24 and the iris ring 26 and is formed of a member separate from the lens barrel body. Although not shown in the drawing, the iris ring 26 has a scale relating to the aperture value, and the second fixed ring 30 has an index (index mark) indicating a reading position with respect to the scale of the iris ring 26. Is marked.

  The “lens barrel main body” herein refers to a member that supports various components of the lens barrel 12 and serves as a skeleton of the lens barrel 12. The first fixed ring 28 and the second fixed ring 30 that are integrally formed with the lens barrel body can be configured as a “fixed lens barrel” or a “fixed ring”. The drive unit 14 is fixed to the first fixed ring 28 and the second fixed ring 30 of the lens barrel 12 via screws 34, 35, and 36.

  Various operation units (reference numerals 40 to 48) are provided on the upper surface portion, the rear end surface, and the bottom surface portion of the drive unit 14. That is, a zoom seesaw switch 40, an iris mode changeover switch 41, an auto switch 42, and a return switch 43 are provided on the upper surface of the drive unit 14 as operation members (see FIG. 1), and on the rear end surface of the drive unit 14 A recording switch 44 is provided (see FIG. 2).

  The zoom seesaw switch 40 is an operation member for changing the focal length of the lens barrel 12. The zoom seesaw switch 40 is swingable back and forth about an axis substantially orthogonal to the optical axis. When the front tele convex portion is pressed, the zoom lens in the lens barrel 12 moves toward the telephoto side. Conversely, when the rear wide convex portion is pressed, it moves toward the wide angle side. In both tele / wide pressing operations, the zooming speed can be adjusted by the amount of pressing (the amount of operation) of the zoom seesaw switch 40. The larger the amount of pressing, the higher the speed. The zoom seesaw switch 40 returns to the neutral position by releasing the press.

  The iris mode changeover switch 41 is means for switching between an auto mode in which iris adjustment is automatically performed and a manual mode in which manual adjustment is performed manually. By sliding the knob of the changeover switch 41 back and forth along the direction substantially parallel to the optical axis, either one of the auto / manual modes can be selectively set.

  The auto switch 42 is a switch for temporarily setting the auto mode when the iris adjustment is set to the manual mode. The iris adjustment is in the auto mode only while the auto switch is pressed.

  The return switch 43 is a switch for switching whether or not to display another screen such as an on-air screen or a screen shot by another camera on a camera viewfinder (an image display device provided in a camera body (not shown)). is there. Each time the return switch 43 is pressed, whether or not to display the other screen in the viewfinder is switched.

  The recording switch 44 is a switch for instructing start and end of recording (recording) of a captured image. Each time the recording switch 44 is pressed, a recording start / end instruction is switched. When recording is started, the video being shot is recorded (recorded) on a recording medium such as a video tape or a memory.

  Reference numeral 50 in FIG. 2 indicates a part of a cable (referred to as “camera connection cable”) for connection with a camera body (not shown). A camera body (not shown) connected to the mount 20 of the lens barrel 12 and the drive unit 14 are electrically connected by the cable 50, and supply of power and transmission / reception of various signals are performed therebetween. Done. Reference numeral 52 denotes a connector for connecting to a remote control system. Reference numeral 54 denotes a belt through hole for attaching a grip belt (not shown). As indicated by reference numeral 55 in FIG. 1, a belt through hole is also formed at the front end portion of the drive unit 14, and the grip belt is attached to the front and rear belt through holes 54 and 55 through the grip belt.

  The photographer can hold the lens barrel 12 together with the drive unit 14 by inserting the right hand (four fingers other than the thumb) between the housing (case) 60 of the drive unit 14 and the grip belt. Further, when the photographer (cameraman) grips the drive unit 14 with the right hand in this way, the recording switch 44 is arranged at a position where the thumb of the right hand is naturally applied (see FIG. 2).

<Structure of drive unit 14>
The drive unit 14 attached to the side surface of the lens barrel 12 is entirely covered with a metal casing (corresponding to a “case”) 60. The housing 60 has a substantially egg-shaped shape (a surface shape in which an egg is laid sideways along the optical axis of the lens barrel 12) so that the cameraman fits in the palm of the hand when gripped with the right hand. The housing 60 is composed of two frame parts (frame parts) having a plane substantially along the optical axis direction of the lens barrel 12 as a split surface. That is, the housing 60 includes a first frame body (corresponding to an “attachment frame”) 62 that forms a side surface on the lens barrel 12 side, and a second frame body 64 that forms an outer side surface that touches the palm of the photographer. It has a structure (two-divided shell structure) that is connected face to face.

  The first frame 62 is fixed to the lens barrel 12 and has a first fixing portion 66 and a first fixing portion 66 that extend to positions facing the respective portions of the first fixed ring 28 and the second fixed ring 30 of the lens barrel 12. 2 fixing portions 68 are formed. The first fixing portion 66 and the second fixing portion 68 have a concave connection surface based on an R shape substantially along the outer peripheral surface (cylindrical surface) of each of the first fixing ring 28 and the second fixing ring 30. The first fixing portion 66 is fixed to the first fixing ring 28 with the screw 34, and the second fixing portion 68 is fixed with the screw 35. A second fixing portion 68 is also provided below the lens barrel 12 (see FIG. 2), and the lower second fixing portion 68 is fixed with a screw 36. With this structure, the first frame body 62 of the drive unit 14 is fixed to the side peripheral surface of the lens barrel 12.

  The second frame body 64, which is configured separately from the first frame body 62, is aligned with the position of a connecting portion (not shown) formed on the periphery of each of the first frame bodies 62. Connected with Thus, the housing 60 of the drive unit 14 is configured by connecting the first frame body 62 and the second frame body 64.

  FIG. 3 is an exploded perspective view showing the internal structure of the drive unit 14. The housing 60 accommodates drive mechanism members related to power transmission such as a motor, a potentiometer, and a gear train that constitute each drive mechanism of the focus drive mechanism, zoom drive mechanism, and iris drive mechanism.

  Reference numeral 70 is an iris motor, and 71 is a zoom motor. As shown in FIG. 3, the iris motor 70, the zoom motor 71, and the gear train 73 that transmits the power of these motors are assembled to the first frame 62. In addition, a circuit board (hereinafter referred to as a “main board”) 77 on which a motor control circuit for each driving mechanism, a control circuit for exchanging signals with the camera, and the like are mounted inside the housing 60. In addition, a protective cover 79 (corresponding to a “cover member”) that partitions the drive mechanism member and the main board 77 is disposed.

  It is desirable that at least the surface of the protective cover 79 has an insulating property. In addition, the surface of the shield layer made of a metal thin film or the like may be covered with an insulating plastic resin so as to have both a surface insulation property and a shielding function for electrical noise generated by a motor or the like. .

  As described above, the members (drive mechanism members) constituting each drive mechanism are attached to the first frame body 62. Further, a protective cover 79 that covers these drive mechanism members is also fixed to the first frame body 62 via fixing screws 81. The first frame 62 may be referred to as an “attachment frame”.

  On the other hand, as described with reference to FIG. 1, various operation members (40 to 43) such as the zoom seesaw switch 40 are attached to the second frame body 64, so that signals from these operation members can be input and A main board (reference numeral 77 in FIG. 3) on which main electronic circuits that perform motor control and the like are mounted is supported on the second frame body 64 side. With such a configuration of the drive unit 14, each member can be efficiently accommodated in the housing 60.

<Mounting structure of cover member>
FIG. 4 is a perspective view showing the inside of the housing with the protective cover 79 assembled thereto. The protective cover 79 is fastened and fixed to the first frame 62 (mounting frame) with four screws (“fixing screws”) 81. FIG. 5 shows an enlarged view of one of the four screwing portions (screw fastening portions) in the protective cover 79 (the portion drawn on the leftmost in FIG. 4). 6 is an exploded perspective view, FIG. 7 is a cross-sectional view, and FIG. 8 is a perspective view drawn through a part.

  As shown in these drawings, the protective cover 79 has a concave shape (corresponding to a “second concave portion”, hereinafter referred to as a “screw receiving concave portion”, denoted by reference numeral 83) in a screw tightened portion by the fixing screw 81. Has been. The screw receiving recess 83 has a screw receiving surface 83A that receives the lower surface of the head 81A of the fixing screw 81 as a bottom, and a wall 84 that covers the periphery of the screw receiving surface 83A (see FIGS. 4 and 5). The protective cover 79 has a through hole 85 (corresponding to a “through hole”) through which the male screw portion 81B of the fixing screw 81 passes through the bottom (screw receiving surface 83A) of each screw receiving recess 83. It is formed (see FIGS. 6 and 7). The screw receiving surface 83 </ b> A formed inside the screw receiving recess 83 is a flat surface having no step from the edge of the through hole 85 to the wall 84.

  On the other hand, the first frame 62 is provided with a boss 86 (corresponding to a “projection”) 86 at a position where the protective cover 79 is screwed and fixed. The boss 86 has a substantially cylindrical shape and has an internal thread portion 87 that opens to the upper end surface 86A thereof.

  On the back surface of each screw receiving recess 83 in the protective cover 79, a concave shape opposite to the screw receiving recess 83 (corresponding to “first recess”, hereinafter referred to as “positioning recess”, indicated by reference numeral 88) is formed. ing. The positioning recess 88 is fitted with the boss 86 of the first frame body 62 to define the mounting position of the protective cover 79. The positioning recess 88 has a connecting surface 88A in contact with the upper end surface 86A of the boss 86, and a wall 89 protrudes around the connecting surface 88A. The connecting surface 88 </ b> A formed inside the positioning recess 88 is a flat surface having no step from the edge of the through hole 85 to the wall 89.

  In this way, the screw receiving surface 83A and the connecting surface 88A are in a front-back relationship (see FIG. 7), and by fitting the boss 86 into the positioning recess 88, the positions of the through hole 85 and the female screw portion 87 coincide. Thus, the protective cover 79 is positioned.

  The protective cover 79 is fixed to the first frame 62 by inserting the screw 81 for fixing the screw receiving recess 83 of the protective cover 79 thus positioned and tightening the fixing screw 81 into the female screw portion 87 (see FIG. 8).

  According to the above structure, since the periphery of the through hole 85 is surrounded by the wall 84 due to the configuration of the screw receiving recess 83, the screw can be prevented from falling off when the fixing screw 81 is tightened. Further, since the fitting structure by the positioning recess 88 is adopted below the portion to be screwed, the positioning of the protective cover 79 at the time of attachment is easy.

<About the depth of the screw receiving recess 83>
The depth D of the screw receiving recess 83 (height of the wall 84) D (see FIG. 7) is appropriately designed from the viewpoint of the effect of preventing the screw from dropping and the restriction on the arrangement space. As the depth of the screw receiving recess 83 is deeper, it is possible to effectively prevent the fixing screw from dropping. However, if the depth of the screw receiving recess 83 is excessively deeper than necessary, it is expected that the screw tightening operation may be obstructed. When the fixing screw 81 inserted into the through hole 85 falls during the screw tightening operation, the fallen fixing screw 81 remains in the screw receiving recess 83 (does not fall from the protective cover 79). Therefore, it is preferable to design the depth D (see FIG. 7) of the screw receiving recess 83 from the following viewpoint according to the length of the fixing screw 81 to be used.

  (1) The wall 84 is raised as the fixing screw 81 to be used is longer.

  (2) The depth D of the screw receiving recess 83 is within the screw receiving recess 83 as long as it has a depth of 1/2 or more of the total length of the fixing screw (the length from the tip of the male screw portion to the tip of the head) L. The fixing screw 81 that has fallen down can be retained in the recess.

  (3) The wall 84 can be designed to be lower as the width of the inner bottom surface (screw receiving surface 83A) of the screw receiving recess 83 is larger. In the present embodiment, the size of the screw receiving surface 83A inside the screw receiving recess 83 is equal to or larger than the size of the upper end surface 86A of the projection 86 on which the female screw portion 87 is formed ( 4 to 8).

  (4) If the height (D) of the wall 84 of the screw receiving recess 83 exceeds the total length L of the fixing screw, screwing and tightening operations become difficult. Therefore, the height of the wall 84 is set to the total length of the fixing screw. L or less is preferable.

  In the present embodiment, from the above viewpoint, the size of the screw receiving surface 83A inside the screw receiving recess 83 is equal to or larger than the size of the upper end surface 86A of the protrusion 86 on which the female screw portion 87 is formed. The depth D of the screw receiving recess 83 is designed to be about ½ of the total length L of the fixing screw 81.

  Further, the wall 84 of the screw receiving recess 83 and the wall 89 of the positioning recess 88 are integrally connected, and the outer surfaces of these walls 84 and 89 are substantially parallel to the outer peripheral surface of the boss 86 and are perpendicular in FIG. It is a single curved surface connected straight along.

<About the connection between the drive unit and the lens barrel>
FIG. 9 is a perspective view of the drive unit 14 drawn from the first frame 62 side with the drive unit 14 removed from the lens barrel 12.

  As shown in the figure, the connecting portion 90 of the drive unit 14 with the lens barrel 12 has a concave curved connecting surface 92 along the cylindrical surface corresponding to the outer peripheral shape of the lens barrel 12. Each of the operation rings (21 to 26) and the fixed rings (28, 30) provided on the outer periphery of the lens barrel 12 is a cylindrical surface having the optical axis of the optical system (the central axis of the lens barrel 12) as a central axis. The connecting surface 92 of the drive unit 14 installed on the side surface of the lens barrel 12 is shaped along (a part of) the cylindrical surface with the optical axis as the central axis. And has a shape along a cylindrical surface (not limited to the same diameter) having a large diameter that does not contact any member of the lens barrel 12 with a predetermined gap.

  Openings 92A, 92B, and 92C are formed in the connection surface 92 of the first frame 62 at portions facing the operation ring, and one of the connection gears 94, 95, and 96 is formed from these openings 92A, 92B, and 92C. The part is exposed in a state of protruding outward from the connecting surface 92.

  In a state where the drive unit 14 is installed on the lens barrel 12, the connecting gears 94 to 96 mesh with the gear teeth 21A to 26A corresponding to the operation ring.

  Although not shown in the drawing, in the housing 60 of the drive unit 14, the connection gears 94 to 96 are connected to corresponding motors, potentiometers, and the like.

  Therefore, the current setting positions of the focus lens group, the zoom (magnification) lens group, and the diaphragm in the lens barrel 12 are detected by the potentiometer in the drive unit 14, and the focus lens group, zoom (magnification). ) The lens group and the diaphragm can be driven by a motor in the housing 60 of the drive unit 14.

  In the present embodiment, all of the focus lens group, the zoom (magnification / magnification) lens group, and the diaphragm can be electrically driven by the drive unit 14. However, in implementing the present invention, all of these movable elements are not necessarily used. It is not required to be driven by the drive unit 14. Any drive unit that can drive at least one movable element may be used. However, in the case of a lens device used in a television camera, it is desirable that the driving unit be capable of driving at least the variable power lens group.

<Assembly procedure>
The assembly procedure for installing the drive unit 14 on the side of the lens barrel 12 is as follows.

  (Procedure 1) First, the first frame 62 is assembled with drive gears such as connecting gears 94 to 96 and other gears and motors (70, 71).

  (Procedure 2) Next, the assembly of the first frame 62 assembled in Procedure 1 is assembled to the side of the lens barrel 12 with screws 34 to 36 (see FIGS. 1 and 2). At this time, the coupling gears 94 to 96 on the first frame body 62 side and the tooth row of the operation ring (21 to 26) on the lens barrel 12 side are checked and assembled in an optimum state. Can do.

  (Procedure 3) Then, the protective cover 79 is attached with the fixing screw 81. After the first frame 62 incorporating gears and motors is fixed to the lens barrel 12, the protective cover 79 is assembled. For this reason, if the fixing screw 81 is dropped at the stage of the assembling operation, the fixed fixing unit is dropped. Although it becomes difficult to pick up the screw 81, etc., according to the present embodiment, the depression of the screw receiving recess 83 can prevent the screw from dropping.

  (Procedure 4) On the other hand, an operation member such as the zoom seesaw switch 40 and the main board 77 are assembled to a second frame 64 that is separate from the first frame 62.

  (Procedure 5) Then, after attaching the protective cover 79 in Procedure 3, the assembly of the second frame body 64 is assembled to the first frame body 62.

  Thus, the lens device 10 described with reference to FIGS.

<About the shape of the protective cover 79>
As shown in FIGS. 3 and 4, the protective cover 79 of this example follows a complicated uneven shape exposed on the main board 77 side of the drive mechanism such as gears and a motor assembled to the first frame 62. Configured to form. In particular, the protective cover 79 of this example has a shape that covers the gear openings 92A, 92B, and 92C (see FIG. 9) of the first frame body 62 and the range that faces the gear train of the drive mechanism section.

  With such a shape, when the gears such as the connection gear rotate, it is possible to effectively prevent the scattering of water and dust from the drive mechanism side to the main board 77.

  Further, the protective cover 79 having such a complicated shape and the screw receiving recess 83 and the positioning recess 88 can be manufactured, for example, by integral molding of resin.

  DESCRIPTION OF SYMBOLS 10 ... Lens apparatus, 12 ... Lens barrel, 14 ... Drive unit (lens drive apparatus), 20 ... Mount part, 21 ... 1st focus ring, 22 ... 2nd focus ring, 24 ... Zoom ring, 26 ... Iris ring, DESCRIPTION OF SYMBOLS 50 ... Cable, 60 ... Housing | casing (case), 62 ... 1st frame (attachment frame), 64 ... 2nd frame, 70 ... Iris motor, 71 ... Zoom motor, 79 ... Protective cover (cover member), 81 ... Fixing screw, 83 ... Screw receiving recess (second recess), 83A ... Screw receiving surface, 84 ... Wall, 86 ... Projection, 87 ... Female thread, 88 ... Positioning recess (first recess), 92A, 92B, 92C ... Opening (gear opening), 94, 95, 96 ... Connecting gear

Claims (7)

In a lens driving device that is attached to a side of a lens barrel that holds an optical system and adjusts the optical system by rotating a rotatable operation ring provided on an outer periphery of the lens barrel.
A drive mechanism including a connection gear that engages with the operation ring and a motor that rotates the connection gear;
A circuit board on which a circuit for controlling the drive mechanism is mounted;
A case in which a gear opening that exposes the connection gear is exposed on a side surface of the case on the lens barrel side, and the drive mechanism portion and the substrate are arranged in order from the lens barrel side;
A cover member disposed between the drive mechanism unit and the circuit board in the case;
With
Using the case as a mounting frame, aligning a female screw portion formed in the mounting frame and a through hole formed in the cover member, and tightening a fixing screw inserted through the through hole to the female screw portion By providing a cover member mounting structure for fixing the cover member to the mounting frame,
The mounting frame is provided with a protrusion having the female screw portion,
A first recess into which the protrusion is fitted is formed on the surface of the cover member on the mounting frame side, and the head of the fixing screw is formed on the surface of the cover member opposite to the first recess. A second recess is formed, and the through hole is formed through the second recess and the first recess opposite to the second recess.
The first recess of the cover member is fitted to the protrusion to match the positions of the female screw portion and the through hole, the fixing screw is inserted from the second recess side, and the fixing screw is A lens driving device characterized in that the mounting structure for fastening to the female screw portion is employed.   2. The lens driving device according to claim 1, wherein a depth of the second recess is not less than ½ of a total length of the fixing screw.   The size of the screw receiving surface for receiving the head portion of the fixing screw inside the second recess is equal to or larger than the size of the upper end surface of the protruding portion on which the female screw portion is formed. The lens driving device according to claim 1 or 2.   4. The lens driving device according to claim 1, wherein the protruding portion has a cylindrical shape, and the female screw portion is formed on an upper end surface of the protruding portion. 5.   5. The lens driving device according to claim 1, wherein the cover member has a shape that covers at least a range facing the gear opening and a gear train of the driving mechanism unit. 6. The case is
A first frame that forms a first side surface facing the lens barrel;
2. A second frame body connected to the first frame body and constituting a second side surface portion outside the lens barrel opposite to the first side surface portion, and constituting a second side surface portion. The lens driving device according to any one of 5.   The lens driving device according to claim 6, wherein the first frame is used as the attachment frame, and the cover member is fixed to the first frame by the fixing screw.

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