JP5461002B2 - Camera aperture device - Google Patents

Description

  The present invention is for a camera in which a diaphragm driving ring that is rotated and rotated by a motor via a gear mechanism rotates a plurality of diaphragm blades simultaneously in the same direction to change the size of the aperture opening stepwise. The present invention relates to a diaphragm device.

  In the diaphragm device for a camera, when the diaphragm drive ring reciprocates within a predetermined rotation angle range around the optical axis, a plurality of diaphragm blades are rotated in the same direction at the same time. There is one in which the size of the aperture is changed continuously or stepwise. In this type of diaphragm device, the diaphragm drive ring was manually rotated in the old days, but now it is usually rotated by a motor. An example of such a configuration is disclosed in Patent Document 1 below. It is described in.

  Further, as described in Patent Document 1, in the case of this type of diaphragm device, the diaphragm drive ring includes a plurality of elongated cam grooves formed so as to be in a substantially equiangular range, and a predetermined angular range. And a plurality of aperture pins connected to the base plate are inserted into the plurality of cam grooves, and the partial gear portion includes: Normally, a gear rotated by a motor is engaged, but the present invention relates to an aperture device for a camera having such a configuration.

JP 2003-57715 A

  In the camera diaphragm device having the above-described configuration, an annular recess having the optical axis as the center is usually formed on the base plate, and the aperture drive ring is disposed in the recess. Therefore, if no measures are taken, the aperture drive ring can be moved slightly in the direction perpendicular to the optical axis due to processing tolerances. The moving direction is also constant depending on how the camera is held. I will not.

  Further, as described above, the diaphragm drive ring is rotated by the motor via the gear mechanism. Therefore, even if the motor rotor stops at a predetermined position, the aperture drive ring is slightly rotatable due to backlash, so the rotation stop position is constant depending on how the camera is held. I will not.

  If the stop position of the aperture drive ring is not determined due to these reasons, the rotation angles of the plurality of aperture blades rotated by the cam groove of the aperture drive ring gradually vary, and the variation state is not constant. Therefore, the size and shape of the aperture opening to be obtained becomes unstable. This is not a significant problem when the aperture is large, but is a major problem when controlling a small aperture.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a diaphragm drive ring that is reciprocally rotated by a motor via a gear mechanism to simultaneously support a plurality of diaphragm blades. In a camera diaphragm device that is rotated in the same direction to control the size of the diaphragm aperture, the diaphragm drive ring can always stop in a predetermined state corresponding to the size of the diaphragm aperture. Therefore, it is an object of the present invention to provide a diaphragm device for a camera that can stably control a diaphragm aperture.

In order to achieve the above object, the diaphragm device for a camera according to the present invention is made of a synthetic resin, each having an opening formed around the optical axis and constituting a blade chamber between the two. The base plate and the cover plate, a plurality of cam grooves formed at substantially equal angular intervals, and a partial gear portion formed only within a predetermined angular range, are formed on the base plate around the optical axis in the blade chamber. A diaphragm drive ring rotatably disposed in the annular recess, and is rotatably fitted to the base plate or the cover plate and meshed with the partial gear portion, and is rotated by a motor to rotate the diaphragm drive ring. The reciprocating gears and the connecting pins inserted into the cam grooves, respectively, are rotatably attached to the base plate or the cover plate at substantially equal angular positions around the optical axis in the blade chamber. Cage drive A plurality of diaphragm blades that are simultaneously rotated in the same direction by the rotation of the ring to change the size of the diaphragm aperture formed in cooperation, and at least one held member provided on the outer periphery of the diaphragm drive ring And at least one holding means provided so as to be close to the held means, and when either one of the held means and the holding means is a magnetic body, The other is a permanent magnet and at least one is provided with a plurality, and all of the held means and the holding means are in an area in an angular direction centered on the optical axis in a plane perpendicular to the optical axis. and is disposed only in a region within a predetermined angle each of the when and the holding means and the holding means to each other are disposed to be close in one-to-one, the rotation of the motor is stopped without energization, most contact So as to maintain to confirm the predetermined stop position of the diaphragm driving ring by a magnetic attractive force acting between at least one pair of said holding means are each other and the object holding means.

  In this case, the diaphragm drive ring is made of a magnetic material, and the holding plate made of a permanent magnet is attached to the base plate at a position where the held means can come close to the diaphragm drive ring. It is preferable that a plurality of protrusions that can be sequentially approached to the holding means are formed on the outer peripheral portion as a plurality of the held means over a predetermined angle range.

  In addition, the diaphragm drive ring is made of a synthetic resin, and one holding means made of a permanent magnet is attached to the base plate at a position where the held means can come close to the diaphragm drive ring. A plurality of magnetic members that can sequentially approach the holding means over a predetermined angle range may be attached to the outer peripheral portion as the plurality of held means.

  Further, the diaphragm drive ring is made of synthetic resin, and one held means made of a permanent magnet is attached to the outer periphery of the diaphragm drive ring, and the ground plate has the held means A plurality of magnetic members arranged so as to be close to each other may be attached as a plurality of the holding means.

  Further, the gear is made of a synthetic resin, the aperture drive ring is made of a magnetic material, and the gear has a plurality of holding means made of permanent magnets attached to the tooth bottom of the gear, Each tooth portion of the partial gear portion formed on the aperture driving ring may also serve as a plurality of the held means.

Further, the gear is made of synthetic resin, the diaphragm drive ring is also made of synthetic resin, and the gear has a plurality of holding means made of permanent magnets attached to the tooth bottom of the gear, A plurality of magnetic members may be attached as a plurality of the held means in the vicinity of each tooth portion of the partial gear portion formed on the aperture driving ring.

  Further, the gear is made of a synthetic resin and the aperture drive ring is made of a magnetic material, and a cylindrical permanent magnet as the holding means is integrally formed around the rotation shaft of the gear. In addition, each tooth portion of the partial gear portion formed on the aperture driving ring may also serve as a plurality of the held means.

  The present invention provides a diaphragm device for a camera in which a diaphragm drive ring that is reciprocally rotated by a motor via a gear mechanism rotates a plurality of diaphragm blades simultaneously in the same direction to control the size of the diaphragm opening. One of the holding means and the held means is provided in the diaphragm drive ring, and when the motor is stopped, the diaphragm drive ring is caused by the magnetic attractive force acting between the holding means and the held means. Since the movement in the direction perpendicular to the optical axis and the movement in the rotational direction are suppressed, the size and shape of all apertures are always stable without being affected by processing tolerances or backlash. There is an effect that it is obtained.

  Embodiments of the present invention will be described with reference to five illustrated examples. As is well known, the camera diaphragm device may be configured as a unit only with the diaphragm device, but may be configured as one unit together with the shutter device or the like. For this reason, each of the diaphragm devices of the embodiments described below is configured only with the diaphragm device as a unit. However, the camera diaphragm device of the present invention has a diaphragm unitized together with the shutter device. A device is also included. 1 to 4 are for explaining the first embodiment, and FIG. 5 is for explaining the second embodiment. 6 to 8 are for explaining the third embodiment, and FIG. 9 is for explaining the fourth embodiment. FIG. 10 is for explaining the fifth embodiment.

  Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a plan view showing a control state of a maximum aperture opening, and FIG. 2 is for explaining an overlapping state of components. FIG. FIG. 3 is a plan view showing a control state of the intermediate aperture, and FIG. 4 is a plan view showing a control state of the minimum aperture. 1, 3, and 4 are all viewed from the lower side of FIG. 2, that is, from the cover plate 2 side, in order to make it easy to see the blade chamber formed between the main plate 1 and the cover plate 2. FIG. 3 is a plan view showing the cover plate 2 removed.

  First, the configuration of the present embodiment will be described mainly with reference to FIGS. Both the base plate 1 and the cover plate 2 of the present embodiment are made of synthetic resin. The cover plate 2 shown in FIG. 2 but not shown in FIG. 1 has substantially the same planar outer shape as the base plate 1 shown in FIG. 1, and is attached to the base plate 1 by means not shown. The blade chamber is formed between the main plate 1 and the base plate 1.

  In addition, circular openings 1a and 2a centering on the optical axis are formed at substantially the center of the base plate 1 and the cover plate 2, but as can be seen from FIG. 2, the opening 1a is more than the opening 2a. Is much larger. Therefore, in the present embodiment, the opening 2a of the cover plate 2 regulates the maximum optical path of the subject light, that is, the size and shape of the maximum aperture opening. In FIGS. 1, 3 and 4, the shape of the opening 1a is omitted, but the shape of the opening 2a is indicated by a two-dot chain line.

  In the present embodiment, the opening 1a is also circular, but the opening 2a is not necessarily circular because the opening 2a regulates the maximum aperture. Further, in this embodiment, the opening 2a regulates the maximum diaphragm opening, but the present invention is not limited to such a configuration, and the diameter of the opening 1a is made smaller to regulate the maximum diaphragm opening. Alternatively, the inner diameter of a diaphragm drive ring 6 to be described later may be made smaller than the diameter of the openings 1a and 2a to restrict the maximum diaphragm opening. This is also true for the following embodiments.

  Next, the shape on the blade chamber side of the main plate 1 will be described. A large annular recess 1b centered on the optical axis is formed on the surface of the main plate 1 on the blade chamber side, and as shown in FIG. 1, adjacent to the outside thereof, it is shallower than the annular recess 1b. Seven steps 1c are formed radially. Each of the stepped portions 1c is formed with one blade attachment hole 1e. Three projecting portions 1d are formed on the inner peripheral wall of the annular recess 1b toward the optical axis.

  Further, three pressing portions 1f are formed adjacent to the inner peripheral wall of the annular recess 1b. These pressing portions 1f protrude toward the cover plate 2 and have a hook shape that partially covers the annular recess 1b toward the optical axis. For this reason, although not shown in the drawings, the blade plate side surface of the cover plate 2 is formed with three recesses for receiving the pressing portions 1f. Furthermore, a mounting hole 1g is formed in the vicinity of the inner peripheral wall of the annular recess 1b, and a permanent magnet bar 3 corresponding to the holding means of the present invention is press-fitted into the mounting hole 1g.

  In the right position of FIG. 1, a gear housing portion 1h deeper than the annular recess 1c is formed adjacent to the annular recess 1b, and a shaft 1i is erected on the bottom surface thereof. Further, a rotor accommodating portion 1j is formed adjacent to the gear accommodating portion 1h. The rotor accommodating portion 1j has a substantially cup shape, and as shown in FIG. It is formed so as to protrude from the opposite surface of 1. A shaft 1k is erected on the bottom surface of the rotor accommodating portion 1j, but it is also known that a metal shaft member is erected by caulking or the like instead of the shaft portion 1k. It has been.

  Next, the structure of the member arrange | positioned at the blade chamber side is demonstrated. First, in the rotor accommodating portion 1j, the rotor 4 is rotatably attached to the shaft 1k. The rotor 4 is a rotor of a known stepping motor, and as can be seen from FIG. 2, a gear portion 4b is formed on one end side of a hollow shaft portion 4a made of synthetic resin, and a circular portion is formed on the other end side. A permanent magnet 4c magnetized so that its peripheral surface has four poles is integrally formed, and the hollow portion of the shaft portion 4a is fitted to the shaft 1k. Further, a parent gear (two-stage gear) 5 is rotatably attached to the shaft 1i provided upright in the gear housing portion 1h, and the parent gear 5a is connected to the gear portion 4b of the rotor 4. Meshed.

  An aperture driving ring 6 made of a magnetic metal is disposed in the annular recess 1b. The diaphragm drive ring 6 has seven cam grooves 6a having the same shape so as to be substantially equiangularly spaced about the optical axis (in FIG. 1, FIG. 3, FIG. 4, only one is labeled). The outer peripheral portion corresponds to the three escape portions 6b, the partial gear portion 6c formed of a plurality of tooth portions formed over a predetermined angular range, and the plurality of held portions of the present invention. Five projecting portions 6d are formed. In addition, the inner diameter of the diaphragm drive ring 6 is smaller than the opening 1a but larger than the opening 2a.

  The diaphragm drive ring 6 has the three relief portions 6b aligned with the positions of the three pressing portions 1f, and the teeth of the partial gear 6c mesh with the child gear 5b of the parent-child gear 5. Thus, the state shown in FIG. 1 is obtained by being dropped into the annular recess 1b and rotated counterclockwise. As will be understood from the following description of the operation, the diaphragm drive ring 6 is rotated clockwise from the state shown in FIG. 1 during the operation, but the three escape portions 6b have the three pressing portions described above. It cannot be rotated until it reaches the position of 1f.

  Although seven diaphragm blades 7 made of synthetic resin having exactly the same shape are arranged in the blade chamber, only one of them is labeled in FIGS. . Each of these diaphragm blades 7 has a blade shaft 7a and a connecting pin 7b on the same surface, and the blade shaft 7a is rotatably fitted in the blade mounting hole 1e of the base plate 1 so that the connecting pin 7b is attached. It is inserted into the cam groove 6 a of the aperture drive ring 6. In this embodiment, seven diaphragm blades are provided, but any number of three or more blades may be used. In such a case, the number of blade mounting holes 1e and cam grooves 6a is the same. Needless to say.

  Finally, the structure of the stator of the stepping motor attached to the surface outside the blade chamber of the main plate 1 will be described. The structure is well known, for example, in Japanese Patent Application Laid-Open No. 2002-131802. Further, the configuration of the stepping motor itself is not directly related to the present invention. Therefore, the configuration of the stator will be briefly described with reference to FIG.

  The stator according to this embodiment includes yokes 8 and 9, hollow bobbins 10 and 11, and coils 12 and 13 wound around the bobbins 10 and 11. Among them, the yokes 8 and 9 are substantially U-shaped with two leg portions and a base portion connecting one end thereof, and are attached to the base plate 1 by appropriate means. The bobbins 10 and 11 are passed through the hollow portions. Moreover, the yokes 8 and 9 are inserted into four holes formed in the rotor accommodating portion 1j with the tips of the two leg portions as magnetic pole portions, and the permanent magnets 4c provided on the rotor 4 are inserted. Although facing the circumferential surface, in FIG. 2, the tip of the leg portion passing through the hollow portion of the bobbins 10 and 11 is inserted into the two holes 1m and 1n among the above four holes. The inserted state is shown.

  Next, the operation of this embodiment will be described mainly with reference to FIGS. FIG. 1 shows a state in which the seven diaphragm blades 7 fully open the opening 2a, that is, a state in which the maximum diaphragm opening is regulated by the opening 2a. In the case of the present embodiment, it is configured such that five stages of aperture openings can be controlled including this state. First, the case of shooting with the maximum aperture will be described.

  In that case, the rotor 4 is stopped in the state shown in FIG. Normally, in this state, the aperture drive ring 6 is in a state where it can move in a direction perpendicular to the optical axis due to processing tolerances. Further, there is backlash between the gear portion 4b of the rotor 4 and the parent gear 5a of the parent gear 5, and between the child gear 5b of the parent gear 5 and the partial gear portion 6c of the aperture drive ring 6, The aperture drive ring 6 can be moved in the rotational direction. For this reason, the position of the aperture drive ring 6 fluctuates depending on how the camera is held and the like due to the combined action thereof.

  However, in the case of the present embodiment, five projecting portions 6d are formed on the outer peripheral portion of the aperture drive ring 6, and the permanent magnet rod 3 is press-fitted into the mounting hole 1g of the base plate 1. In the state 1, the diaphragm drive ring 6 has a magnetic attraction force acting between the protrusion 6d formed on the rightmost side of the five protrusions 6d and the permanent magnet rod 3. A force for displacing in the direction of the permanent magnet bar 3 is acting. Therefore, the backlash is not completely eliminated, and even if a force for rotating the aperture drive ring 6 from the parent gear 5 is applied, the aperture drive ring 6 is moved by the above suction force acting as a holding force. There is no such thing. Therefore, photographing is always performed with the aperture drive ring 6 in the state shown in FIG.

  Next, the case of shooting with an intermediate aperture, that is, the case of shooting with the third aperture, will be described if the state of FIG. 1 is the first level. In this case, at the time of shooting, the rotor 4 is rotated clockwise from the state of FIG. 1 to rotate the aperture drive ring 6 clockwise to the state of FIG. Therefore, the seven diaphragm blades 7 are simultaneously rotated in the clockwise direction, and form a diaphragm aperture by their cooperation. That is, the size and shape of the first stage aperture are regulated by the shape of the opening 2a, but from the second stage to the fifth stage are regulated by seven diaphragm blades 7. Become.

  In the state of FIG. 3, among the five projecting portions 6 d formed on the aperture drive ring 6, the projecting portion 6 d formed in the middle is at a position closest to the permanent magnet rod 3. Therefore, the diaphragm drive ring 6 is displaced in the direction of the permanent magnet bar 3 by the magnetic attractive force acting between the protruding portion 6d and the permanent magnet bar 3 as in the state of FIG. The power to work is working. Thereby, the diaphragm drive ring 6 is not moved by the force received from the parent-child gear 5. Therefore, photographing with this aperture opening is always performed with the aperture drive ring 6 in the state of FIG. 3, so that the aperture formed by the seven aperture blades 7 due to fluctuations in the position of the aperture drive ring 6 as in the prior art. The size and shape of the opening will not change.

  Next, when shooting with the minimum aperture, that is, when shooting with the fifth aperture stop, the rotor 4 is rotated clockwise from the state shown in FIG. The aperture blade 7 is rotated clockwise until the state shown in FIG. Then, in the state of FIG. 4, among the five protrusions 6 d formed on the aperture drive ring 6, the protrusion 6 d formed on the leftmost side is closest to the permanent magnet rod 3. At this time, the diaphragm driving ring 6 is also subjected to a force that is displaced in the direction of the permanent magnet bar 3 in the same manner as in the state of FIGS.

  Accordingly, even in this state, the diaphragm drive ring 6 is not moved by the way the camera is held. Therefore, the size and shape of the aperture opening formed by the seven aperture blades 7 do not change due to the variation in the position of the aperture drive ring 6. When the photographing is completed in the state of FIG. 3 or the state of FIG. 4, the rotor 4 rotates counterclockwise, and the diaphragm drive ring 6 and the seven diaphragm blades 7 are returned to the state of FIG.

  The first, third, and fifth stages have been described so far, but the second and fourth stages are controlled in the same manner as the third and fifth stages. In addition, the diaphragm device of the present embodiment is controlled in five stages, but the diaphragm device of the present invention may have any number of stages as long as it is plural. Moreover, although the above description of the operation has been made on the assumption that the aperture device of the present embodiment is employed in a still camera, it may be employed in a movie camera. In that case, after the rotor 4 is rotated from the state of FIG. 1, the rotor 4 is rotated counterclockwise in response to a change in the light of the subject being photographed, It will be rotated in the direction. These also apply to the following embodiments.

  Next, Embodiment 2 will be described with reference to FIG. 5. FIG. 5 shows a cover plate in order to make the control state of the maximum aperture opening of this embodiment easier to see in the blade chamber, as in FIG. It is the top view which removed 2 and showed. In the present embodiment, the constituent members other than the diaphragm drive ring 6 are the same as those in the first embodiment. Therefore, the same reference numerals are used for the same constituent members and the description thereof is omitted, and only the configuration of the diaphragm drive ring 16 unique to the present embodiment will be described.

  Unlike the diaphragm drive ring 6 of the first embodiment, the diaphragm drive ring 16 of the present embodiment is made of synthetic resin. The shape is similar to that of the diaphragm drive ring 6 of the first embodiment. The seven cam grooves 16a (only one is labeled), the three escape portions 16b, and the partial gear portion 16c are These are formed in the same manner as in the case of the cam groove 6a, the relief portion 6b, and the partial gear portion 6c in the diaphragm drive ring 6 described above.

  However, the diaphragm driving ring 16 of the present embodiment is not formed with the five protrusions 6d formed in the diaphragm driving ring 6 described above. Instead, five magnetic members 17 are attached to the outer peripheral portion of the diaphragm drive ring 16 of the present embodiment, and these are the held means of the present invention. In the case of the present embodiment, these magnetic members 17 have a cylindrical shape and are press-fitted into five holes formed in the aperture driving ring 16. There is no problem. In addition, the shape of the magnetic body member 17 does not need to be cylindrical.

  Also in the case of the present embodiment configured as described above, the control operation of the aperture opening is substantially the same as that of the first embodiment. Therefore, the description is omitted. Also in the case of the present embodiment, the rotation stop state of the aperture drive ring 16 is preferably maintained by the magnetic attractive force acting between the permanent magnet rod 3 and the magnetic member 17 closest to it. Therefore, even if the way of holding the camera is changed, the size and shape of the aperture opening will not change due to the displacement of the aperture drive ring 16.

  In this embodiment, the permanent magnet rod 3 is attached to the base plate 1 and the five magnetic members 17 are attached to the diaphragm drive ring 16. However, in the present invention, the five magnetic members 17 are attached to the base plate 1. And the permanent magnet rod 3 may be attached to the aperture drive ring 16. However, in such a configuration, the operating angle of the suction force with respect to the diaphragm drive ring 16 changes little by little depending on the rotation stop position. Further, the permanent magnet rod 3 of this embodiment may be a magnetic member, and the five magnetic members 17 may be permanent magnets. However, in that case, it is preferable that the distance between the permanent magnet and the magnetic member is narrower than the distance between the permanent magnets.

  Next, Embodiment 3 will be described with reference to FIGS. 6 to 8. FIG. 6 is a plan view showing a control state of the maximum aperture opening in the present embodiment in the same manner as FIG. FIG. 7 is a cross-sectional view for explaining the overlapping state of the constituent members of the present embodiment in the same manner as FIG. Further, FIG. 8 is a plan view showing a control state of the minimum aperture opening in the present embodiment in the same manner as FIG. 4 described above.

  The present embodiment differs from the first embodiment only in a part of the configuration of the main plate 1, the parent-child gear 5, and the aperture drive ring 6. Therefore, the same reference numerals as those in the first embodiment are used for these members, and only different points will be described in detail. In addition, since the other members are exactly the same as those in the first embodiment, the same reference numerals as those in the first embodiment are given to the members and the description thereof is omitted.

  First, the base plate 1 of the present embodiment does not have the permanent magnet rod 3 attached as in the first embodiment. Therefore, the mounting hole 1g is not formed. Further, two projecting portions 1d formed on the inner peripheral wall of the annular recess 1b are added to the upper region of FIG. Furthermore, the position of the pressing portion 1d formed in the upper region of FIG. 6 has moved to the left than in the case of the first embodiment. Other shapes of the main plate 1 are the same as those in the first embodiment.

  Further, in the master gear 5 of this embodiment, each tooth bottom of the slave gear 5b is deeply formed so as to have a substantially C-shaped planar shape, and a total of eight permanent magnet rods 18 are press-fitted into the parts. Has been. These permanent magnet rods 18 may be formed integrally with the parent-child gear 5 or may be bonded to the parent-child gear 5 with an adhesive. In this embodiment, since the permanent magnet rod 3 is not attached to the main plate 1 as in the first embodiment, these permanent magnet rods 18 are the holding means of the present invention. Other shapes of the parent-child gear 5 are the same as those in the first embodiment. In the case of this embodiment, the permanent magnet rod 18 is press-fitted so that a part of the peripheral surface can be seen as a surface when viewed from the tip of the tooth portion of the partial gear portion 6c of the aperture drive ring 6. However, it may be visible as a line or may be press-fitted so as not to be seen at all. Moreover, even if it is a case where a part of peripheral surface is made visible as a surface like a present Example, it may be made to leave a part of tooth base by it.

  Further, the aperture drive ring 6 of the present embodiment is made of a magnetic material as in the case of the first embodiment. However, the five protruding portions 6d are not formed on the outer peripheral portion as in the first embodiment. Instead, in the present embodiment, the plurality of tooth portions of the partial gear portion 6c also serve as the held means of the present invention. Further, as described above, since the position of the pressing portion 1f formed in the upper region of FIG. 6 is different from that of the first embodiment as the number of the protruding portions 1d is increased, the pressing portion 1f. The formation position of the relief portion 6b corresponding to is also changed. Other shapes of the aperture drive ring 6 are the same as those in the first embodiment.

  Also in the case of the present embodiment having such a configuration, the aperture opening control operation is performed in the same manner as in the first embodiment. Therefore, the control state of the minimum aperture is shown in FIG. Also in the case of the present embodiment, the rotation stop state of the aperture driving ring 6 acts between one of the permanent magnet rods 18 and one of the teeth of the partial gear portion 6c that are closest to each other. Since it is suitably maintained by the suction force, the size and shape of the aperture opening will not change due to the displacement of the aperture drive ring 6 even if the way of holding the camera is changed.

  Particularly in the case of the present embodiment, when the rotor 4 is stopped, the diaphragm drive ring 6 is attracted to the permanent magnet rod 18 so that one tooth portion of the partial gear portion 6c is replaced by two teeth of the sub gear 5b. Since the teeth are completely in contact with each other and the suction force acts toward the shaft 1i, the backlash between the child gear 5b and the partial gear portion 6c is eliminated, and at the same time, the rotor 4 There is a feature that it is difficult to rotate in either direction due to the influence of backlash between the gear portion 4b and the parent gear 5a. This also applies to the following Examples 4 and 5.

  Next, Embodiment 4 will be described with reference to FIG. 9. FIG. 9 is a plan view showing a control state of the maximum aperture opening in this embodiment, as in FIG. The present embodiment has the same configuration as that of the third embodiment except for the diaphragm drive ring 6. Therefore, the same reference numerals are given to the same components as those in the third embodiment, and description thereof will be omitted.

  Unlike the diaphragm drive ring 6 of the third embodiment, the diaphragm drive ring 26 of the present embodiment is made of synthetic resin. The shape is similar to that of the diaphragm drive ring 6 of the third embodiment, and the seven cam grooves 26a, the three escape portions 26b, and the partial gear portion 26c are cams in the diaphragm drive ring 6 of the third embodiment. The groove 6a, the relief portion 6b, and the partial gear portion 6c are formed in exactly the same manner.

  However, in the diaphragm drive ring 26 of the present embodiment, five magnetic members 27 are attached to the roots of the five tooth portions of the plurality of tooth portions of the partial gear portion 26c as the held means of the present invention. Yes. In the case of the present embodiment, these magnetic members 27 have a cylindrical shape like the magnetic member 17 in the second embodiment, and are press-fitted into five holes formed in the diaphragm drive ring 26. The diaphragm drive ring 26 may be integrally formed. Also in the case of the present embodiment, the shape of the magnetic member 17 does not need to be cylindrical.

  Also in the case of the present embodiment having such a configuration, the control operation of the aperture opening is substantially the same as that in the third embodiment. Therefore, the description is omitted. Also in the case of the present embodiment, the rotation stop state of the aperture driving ring 26 is preferably maintained by the magnetic attractive force acting between the permanent magnet rod 18 and the magnetic member 27 closest to the permanent magnet rod 18. Therefore, even if the way of holding the camera is changed, the size and shape of the aperture opening does not change due to the displacement of the aperture drive ring 26.

  Next, Embodiment 5 will be described with reference to FIG. 10. FIG. 10 is a plan view showing a control state of the maximum aperture opening in this embodiment, as in FIG. The present embodiment has the same configuration as that of the third embodiment except for the parent-child gear 5. Therefore, the same reference numerals are given to the same components as those in the third embodiment, and description thereof will be omitted.

In the present embodiment, unlike the third and fourth embodiments, the master gear 15a and the slave gear 15b of the master-slave gear 15 are made of synthetic resin so that the master gear 5a and the slave gear of the master-slave gear 5 in Example 1 are made of synthetic resin. The outer shape is the same as that of 5b. However, in the master-slave gear 15 of this embodiment, the permanent magnet cylinder 28 is attached by integral molding so as not to be exposed at the tooth bottom of the slave gear 15b. Therefore, in the case of this embodiment, the permanent magnet tube 28, and it is retained means of the present invention.

  Also in the case of the present embodiment having such a configuration, the control operation of the aperture opening is substantially the same as that in the third embodiment. Therefore, the description is omitted. Also in the case of the present embodiment, the rotation stop state of the aperture drive ring 6 is the attraction force acting between the permanent magnet cylinder 28 and one of the tooth portions of the partial gear portion 6c closest thereto. Therefore, even if the way of holding the camera is changed, the size and shape of the aperture opening will not change due to the displacement of the aperture drive ring 6.

It is the top view of Example 1 which showed the control state of the largest aperture opening. It is sectional drawing for demonstrating the overlapping state of the member which comprises Example 1. FIG. FIG. 3 is a plan view of the first embodiment showing a control state of an intermediate aperture opening. It is the top view of Example 1 which showed the control state of the minimum aperture stop. It is the top view of Example 2 which showed the control state of the largest aperture opening. It is the top view of Example 3 which showed the control state of the largest aperture opening. FIG. 10 is a cross-sectional view for explaining an overlapping state of members constituting Example 3. It is the top view of Example 3 which showed the control state of the minimum aperture stop. It is the top view of Example 4 which showed the control state of the largest aperture opening. It is the top view of Example 5 which showed the control state of the largest aperture opening.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground plate 1a, 2a Opening part 1b Annular recessed part 1c Step part 1d, 6d Protruding part 1e Blade attachment hole 1f Holding part 1g Attachment hole 1h Gear accommodation part 1i, 1k Shaft 1j Rotor accommodation part 1m, 1n hole 2 Cover plate 3 , 18 Permanent magnet rod 4 Rotor 4a Shaft portion 4b Gear portion 4c Permanent magnet 5, 15 Parent-child gear 5a, 15a Parent gear 5b, 15b Child gear 6, 16, 26 Throttle drive ring 6a, 16a, 26a Cam groove 6b, 16b , 26b Escape part 6c, 16c, 26c Partial gear part 7 Diaphragm blade 7a Blade shaft 7b Connection pin 8, 9 Yoke 10, 11 Bobbin 12, 13 Coil 17, 27 Magnetic member 28 Permanent magnet cylinder

Claims (7)

A synthetic resin base plate and cover plate, each having an opening formed around the optical axis and forming a blade chamber between them, and a plurality of cam grooves formed at substantially equal angular intervals And a partial gear portion formed only within a predetermined angle range, and a diaphragm drive ring that is rotatably arranged in an annular recess formed in the base plate around the optical axis in the blade chamber, Gears meshed with the partial gear portion and rotatably attached to the base plate or cover plate, rotated by a motor and reciprocally rotated the diaphragm drive ring, and connecting pins inserted into the cam grooves, respectively. And is rotatably attached to the main plate or the cover plate at substantially equiangular intervals around the optical axis in the blade chamber, and is simultaneously rotated in the same direction by the rotation of the diaphragm drive ring. The A plurality of diaphragm blades that change the size of the aperture opening formed, at least one held means provided on the outer periphery of the diaphragm drive ring, and provided so as to be close to the held means At least one holding means, and when one of the held means and the holding means is a magnetic body, the other is a permanent magnet and at least one of the holding means is provided in plural. and has all of the object holding means and the holding means, predetermined disposed only in the region of the angle and each of the object of the angular direction around the optical axis in a plane orthogonal to the optical axis region The holding means and the holding means are arranged so as to be close to each other in a one-to-one relationship , and when the rotation of the motor is stopped without energization, at least one pair of the holding means and the held object that are closest to each other hand Aperture camera device is characterized in that in order to maintain to confirm the predetermined stop position of the diaphragm driving ring by a magnetic attractive force acting between.   The diaphragm drive ring is made of a magnetic material, and the holding plate is attached to the base plate at a position where the holding means can be brought close to the outer periphery of the diaphragm drive ring. 2. The camera diaphragm device according to claim 1, wherein a plurality of protrusions that can approach the holding unit in order over a predetermined angle range are formed as the plurality of held units.   The diaphragm drive ring is made of a synthetic resin, and the holding plate made of a permanent magnet is attached to the base plate at a position where the held means can approach, and the outer periphery of the diaphragm drive ring The camera diaphragm device according to claim 1, wherein a plurality of magnetic members that can sequentially approach the holding unit over a predetermined angle range are attached as the plurality of held units.   The aperture drive ring is made of a synthetic resin, and one held means made of a permanent magnet is attached to the outer periphery of the aperture drive ring, and the held means is close to the base plate. The camera diaphragm device according to claim 1, wherein a plurality of magnetic members arranged in such a manner are attached as a plurality of the holding means.   The gear is made of a synthetic resin, the diaphragm drive ring is made of a magnetic material, and the gear has a plurality of holding means made of permanent magnets attached to the tooth bottom of the gear. 2. The aperture device for a camera according to claim 1, wherein each tooth portion of the partial gear portion formed on the drive ring also serves as a plurality of the held means.   The gear is made of synthetic resin, the diaphragm drive ring is also made of synthetic resin, and the gear has a plurality of holding means made of permanent magnets attached to the tooth bottom of the gear. 2. The camera diaphragm according to claim 1, wherein a plurality of magnetic members are attached as a plurality of the held means in the vicinity of each tooth portion of the partial gear portion formed in the drive ring. apparatus.   The gear is made of a synthetic resin, the diaphragm drive ring is made of a magnetic material, and a cylindrical permanent magnet as the holding means is integrally formed around the rotation shaft of the gear. The camera diaphragm device according to claim 1, wherein each tooth portion of the partial gear portion formed on the diaphragm drive ring also serves as a plurality of the held means.

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