JP2015125312A - Power transmission mechanism and imaging lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components structured to transmit power having a slip gear.SOLUTION: The power transmission mechanism includes: a first gear 101 pivotally supported by a gear bottom board 11 and having a gear hole; and a second gear 102 having a gear shaft to be engaged and inserted into the gear hole. A first inclined tooth of the first gear and a second inclined tooth of the second gear are held so as to be brought into contact with each other. The first inclined tooth and the second inclined tooth are held by inserting an abutting shaft 102a of the second gear into a gear cover 108. Gear pressing means 104 is held on positioning means 108a on the gear cover. The first gear and the second gear are integrally rotated by pressing the abutting gear with the gear pressing means. The first inclined tooth and the second inclined tooth are separated from each other by power transmission of a predetermined torque or more so as to release the power transmission of the first gear and the second gear. The axial line between the gear pressing means of the gear cover and the abutting axis arranges optical system detection means 110 for detecting a rotation of the gear at a discontinuous position.

Description

  The present invention relates to a power transmission mechanism for driving a photographic lens barrel provided in a digital camera or the like, and a photographic lens barrel having a power transmission mechanism.

  Digital cameras are often used as tools for taking photographs. Digital cameras include a photographic lens barrel having an optical lens, and many photographic lens barrels have a zoom mechanism. The zoom lens moves the optical lens in the optical axis direction, and the image can be taken while changing the image from the wide angle to the telephoto region.

  When the photographic lens barrel is extended, the lens is greatly convex from the camera and often receives an external impact. When the photographing lens barrel is pushed from the front, there is a problem that the internal power transmission mechanism is easily destroyed. Various proposals have been made for such problems as follows.

  Patent Document 1 shows a part of a gear configuration provided in a power transmission mechanism. The photographing lens barrel is driven by a gear from a motor that is a power driving source, and a slip gear is provided in a part of the gear to prevent destruction of the gear train. As a structure of the gear slip mechanism, a coil spring is inserted into a metal shaft, the two gears are brought into close contact with each other, and fixed with a washer. When the photographing lens barrel receives pressure from the front, the close contact between the two gears causes the gears to slip, preventing the gear teeth themselves from being destroyed.

JP 2002-195313 JP

  In Patent Document 1, a slip gear is configured by using a coil spring, but the load increases in terms of work, for example, the number of parts is large and a nut is fitted. In addition, the coil spring must be placed inside the gear, and the diameter of the slip gear is increased accordingly.

  In recent years, miniaturization of cameras has progressed, and there is a need for a photographing lens barrel that is small, easy to assemble, and low in cost and strong against external impacts.

A gear base plate means (11), a first gear means (101) pivotally supported by the gear base plate means (11) and provided with a gear hole means (101a), and fitted and inserted into the gear hole means (101a). Second gear means (102) having gear shaft means (102b), the first gear means (101) has first inclined tooth means (101b), and the second gear means (102) has A second inclined tooth means (102c), the first inclined tooth means (101b) and the second inclined tooth means (102c) are held so as to be in contact with each other, and are provided in the second gear means (102). Holding the contact shaft (102a) by inserting it into the gear cover means (108),
The positioning means (108a) provided on the gear cover means (108) holds the gear pressing means (104) so as to be positionable, and the gear cover means (108) and the gear with respect to the gear base plate means (11). Both pressing means (104) are screw-fixed at the same time, and the gear pressing means (104) presses the contact shaft (102a) so that the first gear means (101) and the second gear means (102) are integrated. The first inclined tooth means (101b) and the second inclined tooth means (102c) are separated from each other and the first gear means (101) and the first Disengage the power transmission of the two gear means (102), the gear cover means (108) is provided with an optical detection means (110) for detecting the rotation of the gear, the gear pressing means (104) and the contact shaft The optical detection means (110) is disposed at a position discontinuous with the axis with (102a) so that the optical detection means (110) does not fall off the gear pressing means (104). The optical detection holding means (104a) for holding is integrally provided.

  According to the present invention, the power transmission mechanism can be configured with a small number of parts without increasing the size.

1 is a perspective view of a photographic lens barrel having a power transmission mechanism in one embodiment of the present invention. It is sectional drawing of the power transmission mechanism in one Example of this invention. It is sectional drawing of the power transmission mechanism in one Example of this invention. It is a disassembled perspective view of the power transmission mechanism in one Example of this invention. It is sectional drawing of the accommodation state of the imaging lens barrel in one Example of this invention. It is sectional drawing of the drawing-out state of the photographic lens barrel in one Example of this invention. 1 is a perspective view of the inside of a taking lens barrel in an embodiment of the present invention. It is a disassembled perspective view of the photographic lens barrel in one Example of this invention. 1 is a front perspective view of a photographing apparatus having a photographing lens barrel in one embodiment of the present invention. 1 is a rear view of a photographing apparatus having a photographing lens barrel in one embodiment of the present invention. 1 is a block diagram showing a configuration of a digital camera that is a photographing apparatus having a photographing lens barrel in one embodiment of the present invention.

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

[Example]
7a and 7b show a digital camera 23 as an image pickup apparatus having a photographing lens barrel according to this embodiment. The digital camera 23 shown in the present embodiment is a camera having a zoom mechanism that can change the photographing magnification.

  FIG. 7 a is a front perspective view of the digital camera 23. FIG. 7 b is a rear view of the digital camera 23. FIG. 8 shows a block diagram of the digital camera 23.

  A finder 21 that determines the composition of the subject, an auxiliary light 20 that assists the light source when performing photometric distance measurement, a strobe 22, and a photographic lens barrel 16 are configured in front of the digital camera 23 of this embodiment.

  A release button 17, a zoom changeover switch 18, and a power supply changeover button 19 are arranged on the upper surface.

  Operation buttons 26, 27, 28, 29, 30, and 31 are arranged on the back, and various functions can be switched. A display (liquid crystal means) 25 made of LCD and a viewfinder eyepiece 24 are arranged.

  The display 24 is an image display means, and displays the image data stored in the memory 39 and the image data read from the memory card on the screen.

  The control unit includes a CPU 45, a ROM 44, and a RAM 46, and various components such as a release button 17, operation buttons 26 to 31, a display 25, a memory 39, and a memory card drive 41 are connected via a bus 43.

  The drive circuit 42 connected to the control system via the bus 43 is connected to the zoom mechanism 32, the focus drive mechanism 7, the shutter drive mechanism 33, the aperture drive means 35, the image sensor 10 such as a CCD or CMOS, and the strobe 22. Each drive is controlled by a signal from the control system.

  The ROM 44 stores a program for controlling each functional component described above. The RAM 46 stores data necessary for each control program.

  The analog signal processing means 36 performs analog processing on the captured image data and outputs it to the A / D converter 37. The A / D converter 37 converts the captured analog data into digital data. This digital data is output to the digital signal processing means 38, where the digital data is processed. Finally, the digital data is stored in the memory 39.

  The image data stored in the memory 39 and the image data stored in the memory card drive 41 can be expanded by the compression / expansion means 40, and the image data can be displayed on the display 25 via the bus 43. When the user views the data on the display 25 and determines that the image is unnecessary, the user can delete the image by operating the operation button 26.

  Next, the configuration of the taking lens barrel 16 provided in the digital camera 23 according to this embodiment will be described.

  FIG. 4 a shows a sectional view of the photographic lens barrel 16 in the housed state. FIG. 4B shows a sectional view of the taking lens barrel 16 in the extended state. FIG. 5 is a perspective view of parts used inside the taking lens barrel 16. FIG. 6 is an exploded perspective view of the photographic lens barrel 16. The configuration of the taking lens barrel 16 is shown below.

  The first lens group 1b holds the first photographing lens means 1a. A barrier group 1 is disposed in front of the first lens group 1b. A second lens group 2 is disposed behind the first lens group 1b, and a third lens group 3 is disposed behind the second lens group 2. The second lens group 2 holds second photographic lens means 2b. The third lens group 3 is divided into a shutter portion and a lens holding portion. The third lens holding portion 13 holds the third photographing lens means 3a, and the shutter means is provided behind the third photographing lens means 3a.

  A fourth lens group 4, which is an anti-vibration lens group, is disposed behind the third lens group 3, and a fourth photographing lens unit 4 a is held in the fourth lens group 4. A sixth lens group 6 that is a focus unit is disposed behind the fourth lens group 4. The sixth lens group 6 is divided into a focus base means 6 and a focus lens 5 a, and the focus lens 5 a is held by the focus lens holding means 5.

  Here, for convenience, the focus lens means 5a and the lens means 5a, the focus lens holding means 5 and the lens holding means 5, and the focus motor means fixed to the focus base means 6 that treats the focus motor means 7 and the lens driving means 7 as the same. 7, the focus lens holding means 5 moves in the direction of the optical axis to focus the camera. A movable cam ring 8 is disposed on the outer periphery of the second lens group 2, the third lens group 3, and the fourth lens group 4.

  By following the plurality of cam grooves provided on the inner periphery of the movable cam ring 8, the second lens group 2, the third lens group 3, and the fourth lens group 4 can move in the optical axis direction. The first lens group 1b can be moved in the optical axis direction by a cam groove provided on the outer periphery of the movable cam ring 8.

  The barrier group 1 is disposed on the outer periphery of the first lens group 1b, and can follow a cam groove different from the cam groove that the first lens group 1b provided on the outer periphery of the movable cam ring 8 follows. Yes. The movement trajectories of the first lens group 1b and the barrier group 1 are different.

  A fixed cam ring 9 is arranged on the outer periphery of the moving cam ring 8, and the moving cam ring 8 can move in the optical axis direction by a cam groove provided on the inner periphery of the fixed cam ring 9. A drive ring 14 is disposed on the outer periphery of the fixed cam ring 9, and the outer periphery thereof is protected by the cover means 12. The sixth lens group 6 follows a cam groove provided on the inner periphery of the drive ring 14. The straight movement is restricted by the fixed cam means 9.

  When the drive ring 14 rotates the outer periphery of the fixed cam ring 9 by the zoom mechanism 32, the sixth lens group 6 moves back and forth in the optical axis direction along the cam groove. As the drive ring 14 rotates, the moving cam ring 8 itself also rotates on the inner periphery of the fixed cam ring 9, and the moving cam ring follower means 8 b provided on the moving cam ring 8 enters the fixed cam groove 9 a of the fixed cam ring 9. By following, it moves back and forth in the optical axis direction.

  As the moving cam ring 8 rotates, the barrier group 1, the first lens group 1b, the second lens group 2, the third lens group 3, the fourth lens group 4, and the sixth lens group 6 move in the optical axis direction. . The focus base of the sixth lens group 6 is integrally provided with a straight travel restricting means 6b, and holds the straight travel restricting means 3b integrally provided with the shutter means connected to the third lens group 3. It has become.

  The straight travel regulation means 3b has a sheath shape, and the straight travel regulation means 6b is inserted into the sheath. The straight travel regulation means 3b and the straight travel regulation means 6b are arranged in pairs.

  Next, a fourth lens group linear advancement restricting means 3c is provided on the outer peripheral portion of the sheath shape of the straight advancement restricting means 3b, and the fourth lens group linear advancement restricting means 4b provided in the fourth lens group 4 is linearly advanced. Be regulated.

  The second lens group rectilinear advance restricting means 2 c provided in the second lens group 2 is regulated by the second lens group rectilinear restricting means 13 a provided in the third lens group 3. The first lens group is linearly restricted by the first lens group linear advance restriction means 2 a provided in the second lens group 2. The outer cylinder means 8a can be fixed to the outer periphery of the moving cam ring 8 and further to the outer periphery of the first lens group 1b.

  The outer cylinder means 8a is fixed to the movable cam ring 8 by three snap fits.

  Next, description will be given in the order of assembly. First, the internal lens groups are assembled to the movable cam ring 8 alone. The movable cam ring 8 is assembled to the fixed cam ring 9.

  The moving cam ring 8 is incorporated into the fixed cam ring 9 from the back side of the fixed cam ring 8. The moving cam ring follower means 8 b provided in the moving cam ring 8 can be incorporated in a fixed cam groove 9 a provided in the fixed cam ring 9.

  The drive ring 14 is incorporated, and the cover cylinder 12 is used to cover the periphery, and the imaging unit holding means 11 is covered from behind and assembled to cover. In this state, the assembly is not yet completed, but the lens can be adjusted for alignment of the internal optical axis. There are cases in which the lens is tilted or decentered to improve optical performance.

  Thereafter, the movable cam ring 8 is rotated in the feeding direction to rotate to the feeding side assembly phase. Therefore, the first lens group 1b, which is a lens group outside the movable cam ring 8, is assembled, and further the barrier group 1 is assembled. Here, the moving cam ring 8 is once rotated in the storing direction and moved to the feeding side mechanical end.

  In this state, the outer cylinder means 8a is incorporated on the outer periphery of the first lens group 1b and the movable cam ring 8. The barrier means 1 is provided with a barrier blade 1d at the tip, and as shown in FIG. 1b, the barrier blade 1d is opened when the photographing is possible, and the barrier blade 1d is closed when stored in FIG. 1a. Yes.

  The image pickup device 10 held by the image pickup device holding means 15 is disposed on the rearmost surface of the photographing lens barrel 16. The taking lens barrel 16 is operated by a zoom mechanism 32 that is a power transmission mechanism. The zoom mechanism 32 of the present embodiment will be described in detail with reference to FIGS.

  The zoom motor means 103 is fixed to the gear base plate means 11. The gear base plate means 11 also serves as the imaging unit holding means 11. By supplying electric power to the zoom motor means 103, the gear means 105 rotates, and the gear means 106 connected to the gear means 105 rotates. The second gear means 102 and the first gear means 101 to be connected next rotate integrally, and then the gear means 107 rotates to rotate the drive ring 14 to drive the entire taking lens barrel 16.

  Each gear is enclosed between the gear base plate means 11 and the gear cover means 108. The gear means 105 is provided with position detecting blade means 105a, and the gear cover means 108 is provided with position detecting means 110. The position detection means 110 is a so-called photointerrupter that is provided with a slit therebetween to detect an optical passage between the slits. When the gear means 105 rotates and the position detecting blade means 105a passes through the slit portion of the position detecting means 110, the rotation speed and the number of rotations of the zoom motor means 103 are detected and the operation of the photographing lens barrel 16 is controlled. .

  Next, the clutch mechanism provided in the zoom mechanism 32 will be described. FIG. 3 is an exploded perspective view of the clutch mechanism. In this embodiment, the clutch mechanism is composed of first gear means 101 and second gear means 102. The first gear means 101 is incorporated in the gear base plate means 11 and has a gear hole means 101a therein. The second gear means 102 is provided with a gear shaft means 102b, and the first gear means 101 and the second gear means 102 are integrally coupled by inserting the gear shaft means 102b into the gear hole means 101a.

  2 and 3, the first gear means 101 is integrally provided with a trapezoidal first inclined tooth means 101b, and the second gear means 102 is similarly provided with a trapezoidal second inclined tooth means 102c. Accordingly, the first gear means 101 and the second gear means 102 rotate integrally as a result of the engagement of the first inclined tooth means 101b and the second inclined tooth means 102c.

  The second gear means 102 is provided with an abutting shaft 102 a and is pivotally supported by the gear cover means 108. The gear pressing means 104 is positioned and held by the two positioning means 108 a provided in the gear cover means 108, and the contact shaft 102 a is held in the direction of the zoom base plate 11. The gear pressing means 104 is fixed to the gear base plate by the screw fixing means 109 together with the gear cover means 108 and the gear pressing means 104.

  The first gear means 101 and the second gear means 102 can be integrated with each other while being held down against the gear base plate means 11 by the gear pressing means 104, so that the power of the zoom motor means 103 can be transmitted. . At this time, the first inclined tooth means 101b and the second inclined tooth means 102c mesh with each other in the rotation direction, and the first gear means 101 and the second gear means 102 rotate integrally.

  The gear pressing means 104 is integrally provided with a lid-shaped optical detection holding means 104a for preventing the optical detection means 110 from coming off the gear cover means 108. The optical detection holding means 104a is arranged at a position separated from the portion of the gear pressing means 104 that presses the gear, and the screw fixing means 109 is arranged at the branch point. It is designed not to affect.

  Normally, power is transmitted as described above. However, when an impact is applied in front of the taking lens barrel 16 when the camera is used, the clutch mechanism is operated so that the zoom mechanism 32 is not destroyed. When an impact is applied from the front of the taking lens barrel 16, the drive ring 14 rotates in the storage direction, and a rotational force is applied to the gear unit 17. Since the gear unit 17 is rapidly rotated with a large torque, the first gear unit 101 is also rotated with a large torque. When this rotational force becomes somewhat larger than the pressing force of the gear pressing means 104, the second gear means 102 resists the spring force of the gear pressing means 104 by the meshing of the first inclined tooth means 101b and the second inclined tooth means 102c. It floats in the direction of the cover means 108, the first gear means 101 and the second gear means 102 are disconnected, and the first gear means 101 idles.

  By doing so, power is not transmitted to the gear means 106 and the gear means 105, and damage to the gear tooth surface due to impact can be prevented. At this time, it is necessary to lengthen the positioning means 108a so that the positioning hole 104b provided in the gear pressing means 104 does not fall off from the positioning means 108a of the gear cover means 108, and the positioning hole so that the shaft and the hole do not interfere with each other. 104b also needs to be lengthened.

  In the above, the first gear means 101 is provided with the gear hole means 101a, and the second gear means 102 is provided with the gear shaft means 102b. Even if the gear hole means is provided, the same effect can be obtained.

  By adopting the above configuration, it is possible to prevent the zoom mechanism, which is a power transmission mechanism, from being destroyed by an impact with a small number of parts, and to hold the optical detection means.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Barrier group 1b 1st lens group 1c Lens group opening part 1d Barrier blade | wing 2 2nd lens group 3 3rd lens group 3b Straight travel regulation means 3c 4th lens group rectilinear regulation means 4 4th lens group 5 Lens holding means, 1st Five lens groups 5a Lens means
5b Rotation restricted means 6 Focus base means, sixth lens group 6b Lens rotation restriction means 6c Drop-off prevention projection 6d Straight guide means 8 Moving cam ring 8a Outer cylinder means 8b Moving cam ring follower means 8c Cam protrusion 8d Second group cam Groove 8e Cam recess 9 Fixed cam ring 10 Imaging element 11 Imaging unit holding means 15 Imaging element holding means 101 First gear means 101a Gear hole means 101b First inclined tooth means 102 Second gear means 102a Contact shaft 102c Second inclined tooth Means 102b Gear shaft means 104 Gear pressing means 104a Optical detection holding means 110 Optical detection means

Claims (5)

A gear base plate means (11), a first gear means (101) pivotally supported by the gear base plate means (11) and provided with a gear hole means (101a), and fitted and inserted into the gear hole means (101a). Second gear means (102) having gear shaft means (102b), the first gear means (101) has first inclined tooth means (101b), and the second gear means (102) has A second inclined tooth means (102c), the first inclined tooth means (101b) and the second inclined tooth means (102c) are held so as to be in contact with each other, and are provided in the second gear means (102). Holding the contact shaft (102a) by inserting it into the gear cover means (108),
The positioning means (108a) provided on the gear cover means (108) holds the gear pressing means (104) so as to be positionable, and the gear cover means (108) and the gear with respect to the gear base plate means (11). Both pressing means (104) are screw-fixed at the same time, and the gear pressing means (104) presses the contact shaft (102a) so that the first gear means (101) and the second gear means (102) are integrated. The first inclined tooth means (101b) and the second inclined tooth means (102c) are separated from each other and the first gear means (101) and the first Disengage the power transmission of the two gear means (102), the gear cover means (108) is provided with an optical detection means (110) for detecting the rotation of the gear, the gear pressing means (104) and the contact shaft The optical detection means (110) is disposed at a position discontinuous with the axis with (102a) so that the optical detection means (110) does not fall off the gear pressing means (104). A power transmission mechanism characterized in that the optical detection holding means (104a) for holding is integrally provided. A gear base plate means (11), a first gear means (101) pivotally supported by the gear base plate means (11) and provided with a gear shaft means, and a gear hole means into which the gear shaft means is fitted and inserted. The second gear means (102) and the first gear means (101) have first inclined tooth means (101b), and the second gear means (102) has second inclined tooth means (102c). The first inclined tooth means (101b) and the second inclined tooth means (102c) are held so as to be able to contact each other, and the contact shaft (102a) provided in the second gear means (102) is geared. Hold by inserting into the cover means (108),
The positioning means (108a) provided on the gear cover means (108) holds the gear pressing means (104) so as to be positionable, and the gear cover means (108) and the gear with respect to the gear base plate means (11). Both pressing means (104) are screw-fixed at the same time, and the gear pressing means (104) presses the contact shaft (102a) so that the first gear means (101) and the second gear means (102) are integrated. The first inclined tooth means (101b) and the second inclined tooth means (102c) are separated from each other and the first gear means (101) and the first Disengage the power transmission of the two gear means (102), the gear cover means (108) is provided with an optical detection means (110) for detecting the rotation of the gear, the gear pressing means (104) and the contact shaft The optical detection means (110) is disposed at a position discontinuous with the axis with (102a) so that the optical detection means (110) does not fall off the gear pressing means (104). A power transmission mechanism characterized in that the optical detection holding means (104a) for holding is integrally provided. The screw fixing means (109) for fastening the gear base plate means (11) and the gear pressing means (104) is disposed in the vicinity of the optical detection holding means (104a). The power transmission mechanism described. One of the positioning means (108a) is disposed in the vicinity of the contact shaft (102a), the gear pressing means (104) is provided with a slot means (104b) into which the positioning means (108a) is inserted, The elongated hole means (104b) is held so as not to drop off from the positioning means (108a) even when the first inclined tooth means (101b) and the second inclined tooth means (102c) are separated from each other. The power transmission mechanism according to claim 1 or 2. A photographic lens barrel comprising the power transmission mechanism according to any one of claims 1 to 4.