JP2007034236A - Focal plane shutter for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focal plane shutter for cameras, which has a support constitution of a driving member superior in wear resistance. <P>SOLUTION: A shaft 1e stood on a shutter base plate 1 is manufactured by precipitating and hardening nickel plating on an iron material so that a surface hardness is a Vickers hardness of 700 to 900, and an annular thrust receiving part 1e-1 is formed on the top face side of the shutter base plate 1. A revolving shaft part 11a of a driving member 11 for a rear blade, which is tubular and is rotatably fitted to the shaft 1e is manufactured by plating an iron material with nickel so that a surface hardness is a Vickers hardness of 500 to 600Hv, and an annular slide part 11a-1 sliding on the annular thrust receiving part 1e-1 on a concentric circle is formed. Since this constitution is given to the shaft 1e and the revolving shaft part 11a, wear on a thrust slide face is suppressed to sufficiently improve durability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a focal plane shutter for a camera provided with one or two shutter blades having at least one blade.

  The focal plane shutter for a camera is provided with two shutter blades (a front blade (group) and a rear blade (group)), which are referred to as a shutter base plate, an intermediate plate, and an auxiliary base plate. Some are arranged separately in the two blade chambers formed between the plate members. The focal plane shutter having such a configuration is employed in both a film camera and a digital camera. Further, as a focal plane shutter dedicated to a digital camera, there is one provided with only one shutter blade, but in that case, it is arranged in the blade chamber constituted by the above two ground planes. In each case, each shutter blade is configured by applying a parallelogram link mechanism by pivotally supporting one or more blades with respect to two arms having one end pivotally attached to the shutter base plate. It is said.

  In addition, a support plate is attached to the shutter base plate at a predetermined interval in one side region of the exposure opening. Between the shutter base plate and the support plate, a drive member, a set member, and the like rotate. The member is arranged. Among them, the drive member reciprocates one of the two arms to cause the shutter blade to open and close the exposure opening. When the holding force at the exposure operation start position is released by the electromagnet, The shutter blades are rotated by the urging force of the drive spring so as to operate the shutter blades rapidly. Accordingly, in the case where two such shutter members are provided, two such drive members are provided. The set member is operated from the initial position by a member on the camera body side, and rotates the drive member to the set position against the biasing force of the drive spring.

Recently, parts are made of synthetic resin, and the number of drive members made of synthetic resin is increasing. However, there is still a strong demand for metal, and the following Patent Document 1 describes two typical examples where the drive member is made of metal. The main reason why such a configuration is required is that the drive member is rotated against the urging force of a powerful drive spring (torsion coil spring) by the set member, or by the urging force of the drive spring. A severe impact is generated when stopped when rotating, so that even if it is used for a long time, it will not cause deformation in the rotating shaft part, and at a predetermined speed even at high and low temperatures This is so that it can be suitably rotated.
Therefore, as in the above two typical examples, even if the entire drive member is not made of metal, at least only the rotating shaft portion is required to be made of metal. As described above, the present invention relates to a focal plane shutter for a camera provided with a drive member having at least a rotating shaft made of metal.

Japanese Utility Model Publication No. 5-42421

  As described above, Patent Document 1 describes two typical examples. Of these, the first typical example shown in FIG. 1 is such that one end of a metal rotating shaft unit integrated with a drive member is rotatably fitted in a hole of a support member attached to a shutter base plate. And the other end is configured to be rotatably fitted to the hole of the second support member provided on the support plate (may be fitted to the hole provided on the support plate itself). Yes. And the drive member comprised in this way is urged | biased in the rotation direction by the drive spring, Of course, the drive spring is a torsion coil spring, Comprising: One end by the side of a support plate is used as a support plate. Since one end on the shutter base plate side is directly attached to the drive member, the shutter base plate is also biased in the direction (thrust direction). . Therefore, in the case of the first typical example, an annular thrust receiving portion is formed at the edge of the hole of the support member attached to the shutter base plate, and the rotating shaft portion of the drive member is in sliding contact with the thrust receiving portion. An annular sliding contact portion is formed.

  In the configuration of the first typical example, the driving member is made of metal (usually nickel-plated iron-based material, surface Vickers hardness is 500 to 600 Hv), and is attached to the shutter base plate. Since the supporting member is also made of metal (usually phosphor bronze and the surface has a Vickers hardness of 100 to 260 Hv), until now, the annular sliding contact portion of the driving member and the annular thrust receiving portion of the supporting member The sliding contact relationship completely cleared the durability of the focal plane shutter that had to endure approximately 50,000 shots. However, recent cameras have not only dramatically improved performance but also improved durability in general, so it is not uncommon for specialists and enthusiasts to shoot more than 50,000 times. In the case of a digital camera, since it is possible to easily erase photographed image data, it has become natural to shoot more than twice as much as a film camera. Therefore, even in the case of a focal plane shutter, the durability of 2 to 3 times or more of the conventional one has been required, but if the drive member and the support member are manufactured as before, Wearing powder is generated by sliding contact in the thrust direction, and it is necessary to take some measures.

  On the other hand, the second typical example described in FIG. 2 of Patent Document 1 is a shaft-like metal erected on the shutter base plate (usually nickel-plated iron-based material, The support member having a surface Vickers hardness of 500 to 600 Hv is made of a tubular metal integrated with the drive member (usually nickel-plated on an iron-based material, and the surface Vickers hardness is 500 ˜600 Hv) is configured to be rotatably fitted. And also in this structure, the drive member is urged | biased by the direction of a shutter base plate simultaneously with the urging | biasing direction by the drive spring. Therefore, in the case of this second typical example, a hook-shaped annular thrust receiving portion is formed at the end of the shaft-shaped support member on the shutter base plate side, and the tubular shaft of the drive member is formed. At the end, an annular sliding contact portion is formed that is in sliding contact with the annular thrust receiving portion. However, even in the case of the second typical example having such a configuration, it is impossible to obtain durability that is two to three times as high as that of the conventional example if manufactured as before.

  The present invention has been made in order to solve such problems. The object of the present invention is to provide a shutter blade that is rotated by an urging force of a drive spring at least when a rotating shaft portion is made of metal and is photographed. In a focal plane shutter having a drive member to be operated and a metal support member attached to a shutter base plate and rotatably supporting the drive member, the focal plane shutter is formed on a rotation shaft portion of the drive member. To provide a focal plane shutter for a camera in which sliding contact between an annular sliding contact portion and an annular thrust receiving portion formed on a support member is excellent in wear resistance.

  In order to achieve the above object, the present invention has at least one drive member that has a metal rotating shaft portion and is rotated by an urging force of a drive spring during shooting to operate a shutter blade, and is attached to a shutter base plate. And at least one metal support member that rotatably supports the rotation shaft portion, and is formed around the rotation center of the rotation shaft portion when the drive member rotates. In the focal plane shutter in which the annular sliding contact portion is brought into sliding contact with the annular thrust receiving portion formed on the support member, the rotating shaft portion is nickel-plated on an iron-based member, and its surface The Vickers hardness is 500 to 600 Hv, and the support member is nickel-plated on an iron-based material, and then the surface hardness of the support member is determined by the precipitation effect. So that it is higher than the surface hardness. In that case, it is more preferable that the surface hardness difference between the rotating shaft portion and the support member is 100 to 400 Hv in terms of Vickers hardness.

  In order to achieve the above object, the present invention has at least one drive member that has a metal rotating shaft portion and that is rotated by a biasing force of a drive spring to operate a shutter blade during photographing, and a shutter base plate. And at least one metal support member that rotatably supports the rotary shaft portion, and is formed around the rotation center of the rotary shaft portion when the drive member rotates. In the focal plane shutter in which the annular sliding contact portion is brought into sliding contact with the annular thrust receiving portion formed on the support member, the rotating shaft portion is nickel-plated on an iron-based material, The surface hardness is 500 to 600 Hv in terms of Vickers hardness, and the support member is obtained by applying palladium plating to an iron-based material, and the surface hardness of the rotating shaft portion is Lower than the surface hardness. In this case, it is more preferable that the surface hardness of the support member is in a range up to a Vickers hardness of 150 Hv than the surface hardness of the rotating shaft portion.

  The focal plane shutter for a camera according to the present invention is configured as described above, so that the wear resistance between the annular sliding contact portion of the rotating shaft portion and the annular thrust receiving portion of the support member is further improved. It is possible to withstand photography of up to 3 times or more.

  The embodiment of the present invention will be described with reference to two illustrated examples. Each of these embodiments is a focal plane shutter having two shutter blades, a front blade and a rear blade. However, the present invention is a focal plane shutter dedicated to a digital camera having one shutter blade. Can also be applied. FIG. 1 is a plan view showing the left half when viewed from the subject side in a state where the focal plane shutter of Example 1 is incorporated in a camera, and shows a state immediately after the end of the exposure operation. is there. 2 is a plan view of the first embodiment in the set state viewed in the same manner as FIG. 1, and FIG. 3 is a cross-sectional view of the main part of the first embodiment. Further, FIG. 4 is a cross-sectional view of an essential part of the second embodiment shown in the same manner as FIG.

  First, the configuration of this embodiment will be described. In FIG. 1, the shutter base plate 1 is formed with an opening 1 a having a rectangular shape at a substantially central portion, but FIG. 1 shows only about half left when viewed from the subject side. Only a part of the portion 1a is shown. Further, as shown in FIG. 3, an intermediate plate 2 and an auxiliary base plate 3 are sequentially attached to the back side of the shutter base plate 1 with a predetermined interval, and between the shutter base plate 1 and the intermediate plate 2. The blade chamber of the leading blade is formed, and the blade chamber of the trailing blade is formed between the intermediate plate 2 and the auxiliary base plate 3, but the illustration of the leading blade and the trailing blade is omitted in FIG. . The intermediate plate 2 and the auxiliary base plate 3 are also formed with openings similar to the openings 1a, and usually the three openings are overlapped to restrict the exposure opening. In this embodiment, the description will be made assuming that the shape of the opening 1a regulates the exposure opening.

  In FIG. 1, two arc-shaped elongated holes 1b, 1c are formed on the left side of the opening 1a, and a well-known buffer member 4 having a substantially C-shaped planar shape is formed at the upper end thereof. , 5 are attached. The shafts 1d and 1e provided upright on the shutter base plate 1 are one embodiment of the support member of the present invention. After the iron-based material is plated with nickel, precipitation hardening is performed by heat treatment, It is manufactured so that the hardness is 700 to 900 Hv in terms of Vickers hardness. These shafts 1d and 1e are press-fitted and crimped into the shutter base plate 1, as can be seen from the shaft 1e shown in FIG. 3, and have a shaft portion on the back side of the shutter base plate 1. A portion formed in a bowl shape on the upper surface side of the shutter base plate 1 is a thrust receiving portion 1e-1 (a thrust receiving portion having a similar shape formed on the shaft 1d is not shown). Further, as shown in FIG. 1, a shaft 1f is erected on the surface side of the shutter base plate 1, and on the back side of the shutter base plate 1, as shown in FIG. 1g and 1h are erected.

  Further, as shown in FIG. 3, a support plate 6 and a printed wiring board 7 are attached to the shutter base plate 1 by means not shown in the drawing with a predetermined space between the shutter base plate 1 and the shutter base plate 1. It has been. However, in FIG. 1 and FIG. 2, the illustration thereof is omitted for easy understanding of the drawings. The support plate 6 is made of a relatively thin metal plate and has a plurality of bent portions on the side of the shutter base plate 1 as is well known. In accordance with the method described in Japanese Patent No. -133944, the leading blade electromagnet 8 and the trailing blade electromagnet 9 shown by the one-dot chain line in FIG. The leading blade electromagnet 8 and the trailing blade electromagnet 9 have exactly the same configuration, and each iron core is formed in a U shape and has two magnetic pole portions. Is fitted with a bobbin around which a coil is wound. Further, the support plate 6 is also formed with two claw portions that engage with a tooth portion of a ratchet member, which will be described later, one of which is shown in FIG. On the other hand, a circuit pattern is formed on the printed wiring board 7, to which the coils of the leading blade electromagnet 8 and the trailing blade electromagnet 9 are connected, and a flash tuning switch is connected. Yes.

  A front blade drive member 10 and a rear blade drive member 11 are rotatably attached to the shafts 1d and 1e of the shutter base plate 1 described above. These drive members 10 and 11 are made of metal only in the tubular rotary shaft portions 10a and 11a that are rotatably fitted to the shafts 1d and 1e, and the others are made of synthetic resin. And the rotating shaft parts 10a and 11a give nickel plating to the iron-type material, and are manufactured so that surface hardness may be 500-600Hv in Vickers hardness. These rotary shaft portions 10a and 11a have exactly the same shape, and as can be seen from the rotary shaft portion 11a shown in FIG. 3, the end on the shutter base plate 1 side is a sliding contact portion 11a-1 and rotates. Sometimes, the thrust receiving portion 1e-1 is slidably contacted in an annular shape (circular shape).

  The leading blade driving member 10 and the trailing blade driving member 11 include drive pins 10b and 11b formed of synthetic resin, attachment portions 10c and 11c, in addition to the metal rotating shaft portions 10a and 11a. have. Among them, the drive pins 10b and 11b are provided on the back side and pass through the long holes 1b and 1c of the shutter base plate 1. The cross-sectional shape of the root portion is circular and the cross-sectional shape of the tip portion is oval. I am doing. The drive pins 10b and 11b are elongated holes in the intermediate plate 2 whose tip portions are formed in substantially the same shape as the elongated holes 1c, as shown only in the case of the drive pins 11b in FIG. 2a is penetrated and it inserts in the long groove | channel 3a of the auxiliary | assistant ground plane 3 formed in the substantially same shape as the long hole 1c.

  Further, in FIG. 2, a part of the attachment part 10c is broken, and in FIG. 1, a part of the attachment part 11c is broken so that the inside thereof can be easily understood. Iron piece members 12 and 13 are attached to 10c and 11c. These iron piece members 12 and 13 are in the form of flanges with iron piece portions 12a and 13a that are attracted and held by the iron cores of the electromagnets 8 and 9, shaft portions 12b and 13b that are slidable with respect to the attachment portions 10c and 11c. It is composed of heads 12c and 13c for retaining, and the iron pieces 12a and 13a are projected from the mounting portions 10c and 11c by the compression coil springs 14 and 15 disposed inside the mounting portions 10c and 11c. Is being energized. Further, shaft members 16 and 17 are attached to the drive members 10 and 11, and rollers 18 and 19 are rotatably attached to them.

  A well-known ratchet member is rotatably attached to the support plate 6 at positions corresponding to the shafts 1d and 1e. Their mounting configuration is substantially the same. Further, a leading blade driving spring for urging the leading blade driving member 10 counterclockwise in FIG. 1 is loosely fitted to the rotating shaft portion 10a of the leading blade driving member 10 to drive the trailing blade. A rear blade drive spring for biasing the rear blade drive member 11 counterclockwise in FIG. 1 is loosely fitted to the rotating shaft portion 11 a of the member 11. And the attachment structure of those drive springs is also substantially the same. 1 and 2, the ratchet members and the drive springs are not shown, but their mounting configuration will be described in the case of the ratchet member 20 and the trailing blade drive spring 21 shown in FIG. 3. .

  A cylindrical bearing member 22 is attached to the support plate 6, and the tip of the shaft 1e is inserted therein. The ratchet member 20 has ratchet teeth 20 a on the outer peripheral surface, and is rotatably attached to the outer peripheral surface of the bearing member 22. And the nail | claw part 6a which has the flexibility provided in the support plate 6 engages the front-end | tip part with the ratchet teeth 20a, and prevents the ratchet member 20 from rotating in one direction. In addition, the attachment structure of the ratchet member 20 is known besides this, for example, the attachment structure different from a present Example is shown also in FIG. 2 of patent document 1. FIG.

  The rear blade drive spring 21 is a torsion coil spring, one end of which is hung on the rear blade drive member 11 (the spring hook portion is omitted in FIG. 3), and the other end is a ratchet member 20. It is hung on a spring hooking portion 20b provided inside. Therefore, although the rear blade drive member 11 is urged in the rotational direction by the rear blade drive spring 21, it is also urged in the thrust direction, that is, the direction of the shutter base plate 1. When being rotated by the blade drive spring 21, the annular sliding contact portion 11a-1 of the rotating shaft portion 11a is brought into sliding contact with the annular thrust receiving portion 1e-1 of the shaft 1e. As is well known, when adjusting the biasing force of the trailing blade drive spring 21 during manufacture, the ratchet member 20 is rotated to change the engagement position between the claw portion 6a and the ratchet teeth 20a. However, a method of performing such adjustment without providing the ratchet member 20 is also known. As one of the methods, there is a method in which one end of the drive blade for the rear blade is changed over to a plurality of holes formed in the support plate 6, but when the ratchet member 20 is not provided in this way, Usually, the tip is inserted into the hole of the support plate 6.

  A set member 23 made of synthetic resin is rotatably attached to the shaft 1f of the shutter base plate 1 described above. The set member 23 has a rotating shaft portion 23a fitted to the shaft 1f, pushing portions 23b and 23c, and a pushed portion 23d, and is rotated clockwise by a spring (not shown). In FIG. 1, the rotation is blocked by a stopper (not shown). Hereinafter, for the set member 23, this position is referred to as an initial position.

  Next, the structure of the front blade | wing and rear blade | wing arrange | positioned at the back side of the shutter base plate 1 is demonstrated. First, the leading blade is disposed between the shutter base plate 1 and the intermediate plate 2, and is composed of two arms 24 and 25 and four blades pivotally supported in order in the length direction thereof. Since these configurations are well known, only the slit forming blade 26 pivotally supported at the forefront of the arms 24 and 25 is shown in order to make the drawing easy to see. The arm 24 is rotatably attached to the shaft 1d, and the distal end portion of the drive pin 10b of the leading blade drive member 10 is fitted into the elongated hole 24a. The other arm 25 is rotatably attached to the shaft 1g.

  On the other hand, the rear blade is disposed between the intermediate plate 2 and the auxiliary base plate 3, and is composed of two arms 27 and 28 and four blades pivotally supported in order in the length direction thereof. As in the case of the leading blade, only the slit forming blade 29 pivotally supported at the forefront of the arms 27 and 28 is shown. The arm 27 is rotatably attached to the shaft 1e, and the distal end portion of the drive pin 11b of the rear blade drive member 11 is fitted into the elongated hole 27a. The other arm 28 is rotatably attached to the shaft 1h.

  Next, the operation of this embodiment will be described. FIG. 1 shows a state immediately after the exposure operation is completed. Therefore, the leading blade driving member 10 is biased to rotate counterclockwise by a leading blade driving spring (not shown), but the driving pin 10b is attached to the upper end of the long hole 1b. This stop state is maintained by contacting the buffer member 4. Then, the four blades of the leading blade are overlapped and stored at a position above the opening 1a. On the other hand, the rear blade drive member 11 is also urged to rotate counterclockwise by the rear blade drive spring 21, but the buffer pin 5 is attached to the upper end of the long hole 1 c. This stop state is maintained in contact with. Then, the four blades of the rear blade are developed and cover the opening 1a, but as described above, only the slit forming blade 29 is shown in FIG.

  The setting operation of this embodiment is performed by rotating a setting member 23 counterclockwise by a member on the camera main body (not shown). That is, when the member on the camera body side pushes the driven portion 23d of the set member 23 and rotates the set member 23 counterclockwise against the urging force of a spring (not shown), first, The pushing portion 23b pushes the roller 18 while rotating it, and rotates the leading blade driving member 10 in the clockwise direction against the urging force of a leading blade driving spring (not shown). Further, by this rotation, the driving pin 10b of the leading blade driving member 10 rotates the arm 24 in the clockwise direction, and moves the four blades of the leading blade downward while developing them.

  Thereafter, when the amount of overlap between the slit forming blade 26 of the leading blade and the slit forming blade 29 of the trailing blade reaches a predetermined amount, the pushing portion 23c of the set member 23 pushes while rotating the roller 19 to drive the trailing blade. The rear blade drive member 11 is rotated clockwise against the biasing force of the spring 21, whereby the drive pin 11 b rotates the arm 27 clockwise, and the four blades of the rear blade are moved. Start to move downward while superimposing. Therefore, thereafter, the four blades of the leading blade and the four blades of the rear blade both move downward while suitably maintaining the overlapping amount of the slit forming blades 26 and 29.

  In this way, when the set operation proceeds and only the four blades of the leading blade cover the opening 1a, immediately after that, the iron piece members 12, 13 attached to the drive members 10, 11 are used. However, the iron piece portions 12a and 13a are successively brought into contact with the iron cores of the electromagnets 8 and 9, but the set member 23 is stopped even after the movement of the iron piece members 12 and 13 is stopped by the contact. While the compression springs 14 and 15 are being compressed, the drive members 10 and 11 are stopped when they are slightly rotated. The stopped state is the set state shown in FIG. 2, and at this time, the head portions 12c and 13c of the iron piece members 12 and 13 are all separated from the attachment portions 10c and 11c.

  Next, the exposure operation of this embodiment will be described. When the release button of the camera is pressed in the state of FIG. 2, first, the coils of the electromagnets 8 and 9 are energized, and their iron cores attract and hold the iron piece members 12 and 13. Thereafter, the member on the camera body side (not shown) releases the pressing force of the set member 23 against the driven portion 23d, so that the set member 23 is rotated clockwise by a biasing force of a spring (not shown). Return to the initial position. Further, when the set member 23 returns to the initial position in this way, the iron piece members 12 and 13 do not operate, but each drive member 10 and 11 is attached to the mounting portion by the biasing force of each overcharged drive spring. 10c and 11c are operated until they come into contact with the heads 12c and 13c of the iron piece members 12 and 13. The stop position is the exposure operation start position for the drive members 10 and 11. At this time, both the leading and trailing blades are operated slightly, but the opening 1a is still covered with only the four leading blades.

  In this way, after the set member 23 returns to the initial position, the current to the coil of the leading blade electromagnet 8 is first cut off, and the power to the coil of the trailing blade electromagnet 9 is cut off after a predetermined time. Therefore, first, when the energization to the coil of the leading blade driving member 8 is cut off, the suction holding force to the iron piece member 12 is lost, and the leading blade driving member 10 is caused by the biasing force of the leading blade driving spring (not shown). The arm 24 is rotated counterclockwise by the drive pin 10b. As a result, the four blades of the leading blade are actuated upward while increasing the amount of overlap between the blades, and the slit forming blade 26 opens the opening 1a.

  Thereafter, when the energization to the coil of the rear blade electromagnet 9 is cut off, the suction holding force to the iron piece member 13 is lost, and the rear blade drive member 11 is rotated counterclockwise by the urging force of the rear blade drive spring 21. Then, the arm 27 is rotated counterclockwise by the drive pin 11b. Accordingly, the four blades of the rear blades are operated upward while reducing the amount of overlap between the blades, and the opening 1 a is covered with the slit forming blades 29. Therefore, thereafter, the image plane is exposed by the slit formed by the slit forming blade 26 of the leading blade and the slit forming blade 29 of the trailing blade.

  The leading blade drive member 10 that has started the exposure operation is stopped at the end of the operation, with the drive pin 10b coming into contact with the buffer member 4 attached to the upper end of the long hole 1b, Subsequently, when the operation of the rear blade driving member 11 is completed, the driving pin 11b comes into contact with the buffer member 5 attached to the upper end of the long hole 1c and is stopped. Therefore, in the stopped state, the four blades of the leading blade are overlapped and stored in the upper position of the opening 1a, and the four blades of the rear blade are deployed to cover the opening 1a. The state immediately after the end of the exposure operation is the state shown in FIG.

  By the way, as described above, when performing the exposure operation, the leading blade driving member 10 and the trailing blade driving member 11 are rapidly rotated by the strong biasing force of each driving spring. Therefore, friction is generated between the drive members 10 and 11 and the shafts 1d and 1e, which affects the rotational speed of the drive members 10 and 11 and the durability of the shutter. Therefore, although well known, this point will be described in detail with reference to FIG. First, as described above, the rear blade drive member 11 is subjected to a rotating force and a thrust force toward the shutter base plate 1 by the rear blade drive spring 21. 11, the inner peripheral surface of the rotating shaft portion 11a and the end surface on the shutter base plate 1 side are slidable contact surfaces with respect to the shaft 1e.

  For this reason, conventionally, in the case of a shutter for a high-end camera, as in this embodiment, at least the rotating shaft portion 11a and the shaft 1e are made of an iron-based material, and the surface thereof is plated with nickel, thereby surface hardness. Is made to have a Vickers hardness of 500 to 600 Hv, and during assembly, oil is applied to the outer peripheral surface of the shaft 1e and around the sliding contact surface between the sliding contact portion 11a-1 and the thrust receiving portion 1e-1. I was trying to apply oil. And it goes without saying that the reason for applying the oil is to improve the lubricity and wear resistance, but the sliding contact between the sliding contact portion 11a-1 and the thrust receiving portion 1e-1 is not limited. In the case of surfaces, it was rather important to improve wear resistance.

  However, in the case of a focal plane shutter, until now it has been required to withstand about 50,000 shots, but recently, it has been required to be about 2-3 times more durable. I came. However, it has been found that the above-described configuration may not meet such a requirement. That is, when the number of times of photographing greatly exceeds 50,000 times, the sliding contact surface between the sliding contact portion 11a-1 of the rotating shaft portion 11a and the thrust receiving portion 1e-1 of the shaft 1e becomes the inner periphery of the rotating shaft portion 11a. Since the surface is more easily exposed to the air than the sliding surface between the surface and the outer peripheral surface of the shaft 1e, the oil is spattered or evaporated little by little during sliding, resulting in early oil shortage and wear of the sliding surface. It has been found that the rotational speed of the drive member 11 and the stabilization of the operation are affected. And in that case, it turned out that the thrust receiving part 1e-1 which is a fixed surface is easy to wear.

  The first conceivable method for solving such problems is to increase the amount of oil to be applied. However, when a large amount of oil is applied, the amount of oil splashed with each image capture increases as described above, so that a large amount of oil adheres to the constituent members of the shutter and dust adheres thereon. As a result, there is a risk of causing an undesirable situation in terms of the shutter function. In particular, when employed in a digital camera, scattered fine oil particles accumulate on the front surface of the image sensor, and an image with good image quality cannot be obtained. For this reason, when increasing the amount of oil applied, it is necessary to take another measure to prevent such a situation from occurring.

  Therefore, in consideration of the cost and not depending on such a method, it was studied to improve the wear resistance from the material processing surface of the rotating shaft portion 11a and the shaft 1e. As a result, as described above, when the material of the rotating shaft portion 11a and the conditions of the surface treatment applied thereto are the same as before, the surface hardness of the shaft 1e is only made harder than the surface hardness of the rotating shaft portion 11a. However, it has been found that the effect can be obtained, but it has been found that when a hardness difference of about 100 to 400 Hv is obtained in terms of Vickers hardness, sufficient practical reliability can be obtained. Therefore, in the case of the present embodiment, as described above, the surface hardness of the shaft 1e is nickel-plated and then precipitation-hardened by heat treatment to obtain a Vickers hardness of 700 to 900 Hv, and a desired wear resistance at low cost. Is optimally obtained.

  Also, from the same point of view, it was examined that the shaft 1e was made of an iron-based material and plated with palladium. As a result, it was found that the surface hardness of the shaft 1e was sufficiently obtained when the surface hardness of the rotating shaft portion 11a (Vickers hardness 500 to 600 Hv) was lowered in the range up to about 150 Hv in terms of Vickers hardness. However, in particular, when the surface hardness of the rotating shaft portion 11a is made to be Vickers hardness 500 to 600 Hv by nickel plating, the surface hardness of the shaft 1e is optimized to be Vickers hardness 450 to 550 Hv by applying palladium plating. It was found that abrasion was obtained. Therefore, when the shafts 1d and 1e are manufactured by applying palladium plating to an iron-based material as described above, it is an embodiment of the present invention.

  Next, Example 2 will be described with reference to FIG. The present embodiment has almost the same configuration as the first embodiment. The difference is in the shape of the leading blade driving member and the trailing blade driving member, and their supporting structure. Further, the front blade drive member and the rear blade drive member have the same configuration of the rotation shaft portion, and their support configuration is exactly the same. Therefore, differences from the configuration of the first embodiment will be described with reference to FIG. 4 in the case of the trailing blade driving member and its supporting configuration. In FIG. 4, the same reference numerals are used for the same members and portions as in the first embodiment, and the rear blade drive member 11 also uses the same reference numerals for portions other than the rotating shaft portion. Therefore, the description about them is omitted. Further, when the present embodiment is shown in a plan view in the same manner as the first embodiment, it is substantially the same as FIG. 1 and FIG. For this reason, the operation description of the first embodiment is referred to the operation description of the first embodiment.

  Therefore, the configuration of this embodiment will be described. In the case of the present embodiment, a cylindrical bearing member 30 is caulked to the shutter base plate 1. This bearing member 30 is one embodiment of the support member of the present invention, and after nickel plating is applied to an iron-based material, precipitation hardening is performed by heat treatment so that the surface hardness is 700 to 900 Hv in terms of Vickers hardness. It is made in. The bearing member 30 forms an annular thrust receiving portion 30 a on the upper surface side of the shutter base plate 1. The bearing member 30 is for bearing the rear blade drive member 11, but a bearing member (not shown) for bearing the front blade drive member 10 has the same shape and is the same. In this way, it is attached to the shutter base plate 1.

  Further, in the rear blade drive member 11 of this embodiment, only the columnar rotary shaft portion 11a 'is made of metal, and the others are made of synthetic resin. The rotating shaft portion 11 a ′ has one end rotatably inserted into the hollow portion of the bearing member 22 and the other end inserted rotatably into the hollow portion of the bearing member 30. Further, on the shutter base plate 1 side of the rotating shaft portion 11a ', a sliding contact portion 11a'-1 is formed in an annular shape so as to be in sliding contact with the annular thrust receiving portion 30a of the bearing member 30. The leading blade drive member 10 also has the same rotational shaft portion and is rotatably supported by two bearing members corresponding to the bearing members 22 and 30.

  In this embodiment having such a configuration, the rotating shaft portion 11a ′ is manufactured by applying nickel plating to an iron-based material so that the surface hardness is 500 to 600 Hv in Vickers hardness, and the bearing member 30 is made of an iron-based material. The reason why the material is nickel plated and then subjected to precipitation hardening by heat treatment so that the surface hardness is 700 to 900 Hv in terms of Vickers hardness is the same as the reason described in the first embodiment. When the bearing member 30 is manufactured by applying palladium plating to an iron-based material, the surface hardness is about 150 Hv in terms of Vickers hardness than the surface hardness of the rotating shaft portion 11 a ′ (Vickers hardness 500 to 600 Hv). If the Vickers hardness is set to 450 to 550 Hv, the optimum wear resistance equivalent to that of this example can be obtained. Therefore, as described in the description of the first embodiment, the case where the bearing member 30 is manufactured by performing palladium plating under the above conditions is also an embodiment of the present invention.

  In each of the above-described embodiments, each drive member has been described in the case where only the rotating shaft portion is made of metal. However, in the present invention, all or most of the drive members may be made of metal. Further, each of the above embodiments has been described in the case of a focal plane shutter having two shutter blades, a front blade and a rear blade, and two drive members for driving them. The present invention can also be applied to a focal plane shutter dedicated to a digital camera having only a blade and one drive member. Further, in each of the above embodiments, one shutter blade has four blades, but this kind of focal plane shutter includes one or more than four. There are also known ones, and the present invention is not limited by the number of sheets. Further, in this kind of focal plane shutter, there are the so-called direct type and the latching type as the configuration for holding the shutter blade at the exposure operation start position. Although the example has the former configuration, the present invention can also be applied to the latter configuration.

FIG. 2 is a plan view of the first embodiment viewed from the subject side in a state where the camera is incorporated in a camera, and shows a state immediately after the end of an exposure operation. It is a top view of Example 1 in the set state seen similarly to FIG. 1 is a cross-sectional view of a main part of Example 1. FIG. 10 is a cross-sectional view of a main part of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a Opening part 1b, 1c, 2a, 24a, 27a Long hole 1d, 1e, 1f, 1g, 1h Shaft 1e-1, 30a Thrust receiving part 2 Intermediate | middle board 3 Auxiliary base plate 3a Long groove 4, 5 Buffer member 6 Support Plate 6a Claw portion 7 Printed wiring board 8 Lead blade electromagnet 9 Rear blade electromagnet 10 Lead blade drive member 10a, 11a, 23a, 11a ′ Rotating shaft portion 11a-1, 11a′-1 Sliding contact portion 10b, 11b Drive Pins 10c, 11c Mounting portion 11 Rear blade drive member 12, 13 Iron piece member 12a, 13a Iron piece portion 12b, 13b Shaft portion 12c, 13c Head portion 14, 15 Compression spring 16, 17 Shaft member 18, 19 Roller 20 Ratchet member 20a Ratchet teeth 20b Spring hook portion 21 Rear blade drive spring 22, 30 Bearing member 23 Set member 23b, 23c Pushing 23d the pushing portion 24,25,27,28 arms 26 and 29 slit-forming blade

Claims (4)

  At least one drive member that has a metal rotation shaft portion and rotates by the biasing force of the drive spring to operate the shutter blades at the time of photographing, and is attached to the shutter base plate and rotatably supports the rotation shaft portion. At least one metal support member, and when the drive member rotates, an annular sliding contact portion formed around the rotation center of the rotation shaft portion is formed on the support member. In the focal plane shutter that is in sliding contact with the annular thrust receiving portion, the rotating shaft portion is nickel-plated on an iron-based member, and the surface hardness is 500 to 600 Hv in Vickers hardness, The support member is characterized in that after the nickel plating is applied to the iron-based material, the surface hardness of the support member is higher than the surface hardness of the rotating shaft portion due to the precipitation effect. Camera focal plane shutter that.   2. The focal plane shutter for a camera according to claim 1, wherein a difference in surface hardness between the rotating shaft portion and the support member is 100 to 400 Hv in terms of Vickers hardness.   At least one drive member that has a metal rotation shaft portion and rotates by the biasing force of the drive spring to operate the shutter blades at the time of photographing, and is attached to the shutter base plate and rotatably supports the rotation shaft portion. At least one metal support member, and when the drive member rotates, an annular sliding contact portion formed around the rotation center of the rotation shaft portion is formed on the support member. In the focal plane shutter that is in sliding contact with the annular thrust receiving portion, the rotary shaft portion is nickel-plated on an iron-based material, and the surface hardness is 500 to 600 Hv in Vickers hardness, The support member is a camera in which an iron-based material is plated with palladium, and the surface hardness of the support member is lower than the surface hardness of the rotating shaft portion. Use focal-plane shutter.   4. The focal plane shutter for a camera according to claim 3, wherein the surface hardness of the support member is in a range up to a Vickers hardness of 150 Hv than the surface hardness of the rotating shaft portion.