JP6448389B2 - SHUTTER DEVICE AND IMAGING DEVICE - Google Patents

Description

  The present invention relates to a shutter device used in an imaging device such as a digital camera, and an imaging device including the shutter device.

  As a focal plane shutter provided in an imaging device such as a digital camera, the imaging surface is continuously formed by a slit formed by a front blade group and a rear blade group that reciprocate between a position covering the opening of the shutter base plate and a retracted position. What is exposed to light is known.

  By the way, each blade group has a high traveling speed in order to improve exposure accuracy. Therefore, since the kinetic energy is large and the blade group tends to bounce, each blade group is decelerated using a friction brake at the end of traveling.

  For example, a shutter device that uses both a frictional force and a spring force of a return spring as a braking force of a driving unit of a blade group has been proposed (Patent Document 1). In this proposal, the elastic energy stored by the deformation of the return spring is released in conjunction with the charge of the blade group, thereby assisting the charge of the blade group and reusing part of the running energy for the charge of the blade group. Is possible.

JP 60-103333 A

  In Patent Document 1, the frictional force and the spring force of the return spring are used in combination as the braking force of the driving unit of the blade group. In this case, the higher the ratio of the spring force of the return spring, the higher the ratio of reusing travel energy, and the load on the motor can be reduced when charging the blade group. The brake may move from the original standby position. In particular, when the frictional force of the brake decreases with time, there is a concern that the spring force of the return spring exceeds the frictional force and moves the brake from the original standby position.

  When the brake moves from the original standby position, the braking start timing of the brake shifts, and what is supposed to be applied only at the end of traveling is operated at the traveling intermediate point.

  Therefore, an object of the present invention is to provide a shutter device that can apply a large braking force without affecting the operation of the blade group shielding or opening the exposure opening.

  In order to achieve the above object, the shutter device of the present invention travels from the first standby position to the first travel completion position so that the blade group shields or opens the exposure opening. A drive member that drives the drive member, a drive source that causes the drive member to travel toward the first travel completion position, and a contact before the drive member reaches the first travel completion position. A brake member that decelerates the travel of the drive member toward the first travel completion position by traveling from the standby position to the second travel completion position, and the brake member toward the second standby position Urging means for urging the blade group, and when the brake member is positioned at the second standby position, the urging means does not urge the brake member, and the blade member is moved by the driving member. To be driven , After the slit forming section of the blade group reaches outwardly from the exposure opening, the biasing means is characterized by that urges the brake member.

  According to the present invention, a large braking force can be applied without affecting the operation in which the blade group shields or opens the exposure opening.

1 is a block diagram illustrating a system configuration example of a digital camera that is an example of an embodiment of an imaging apparatus of the present invention. (A) is the figure which looked at the focal plane shutter from the image sensor side, (b) is the figure which looked at the focal plane shutter from the subject side. (A) is the disassembled perspective view which looked at the focal plane shutter from the image pick-up element side, (b) is the disassembled perspective view which looked at the focal plane shutter from the to-be-photographed object side. It is sectional drawing of a rear brake lever. It is a perspective view which shows the arrangement | positioning state of the main drive components of a brake. It is a figure which shows the standby state of a focal plane shutter. It is a figure which shows the state by which the tension | tensile_strength of the front drive lever was cancelled | released. It is a figure which shows the state which the front drive lever contact | abutted to the front brake lever. It is a figure which shows the charge start state of the front drive lever by a brake return spring. It is a figure which shows the driving | running | working completion state of a front blade. It is a figure which shows the state by which the tension | tensile_strength of the rear drive lever was cancelled | released. It is a figure which shows the state which the rear drive lever contact | abutted to the rear brake lever. It is a figure which shows the charge start state of the rear drive lever by a brake return spring. It is a figure which shows the driving | running | working completion state of a rear blade. It is a figure which shows the state which started charge of the front drive lever. The relationship between the rotation angle of the front brake lever, the spring force (torque) of the front brake lever, the spring force (torque) of the brake return spring, the spring force (torque) of the drive spring, and the frictional force (torque) of the brake seat is shown. FIG. It is a graph which shows the relationship between the rotation angle of a front brake lever, the spring force (torque) of a front brake lever, the spring force (torque) of a brake return spring, and the frictional force (torque) by a brake seat in a conventional structure. It is a figure which shows the state which started charge of the front brake lever. It is a figure which shows the state which started the charge of the rear drive lever. It is a figure which shows the state which charge of the front drive lever was completed. It is a figure which shows the state which started the charge of the rear brake lever. It is a figure which shows the state which charge of the rear drive lever was completed.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a system configuration example of a digital camera which is an example of an embodiment of an imaging apparatus of the present invention.

  As shown in FIG. 1, the digital camera of this embodiment includes a photographic lens 401, a focal plane shutter 113, an image sensor 403, a mirror member 481, and a finder optical system 482.

  In the finder observation state, the mirror member 481 reflects a part of the subject luminous flux that has entered the imaging optical path and passed through the imaging lens 401 and guides it to the finder optical system 482. Thereby, the photographer can observe the subject image via the finder optical system 482. When the viewfinder observation state is shifted to the photographing state or the live view state, the mirror member 481 is retracted from the photographing optical path by a driving device (not shown), whereby the subject light flux that has passed through the photographing lens 401 forms an image on the image sensor 403. To do.

  The focal plane shutter 113 is a shutter device that is disposed on the subject side of the image sensor 403 and is driven by a shutter drive circuit 411. The release switch (SW1) 498 is turned on by a half-press operation of a release button (not shown), and the release switch (SW2) 499 is turned on by a full-press operation of the release button. When the release switch (SW1) 498 is turned on, a shooting preparation operation is performed, and when the release switch (SW2) 499 is turned on, shooting is started.

  The image sensor 403 is configured by a CMOS sensor or the like, photoelectrically converts a subject image formed through the photographing lens 401 to generate an analog image signal, and outputs the analog image signal to an AFE (Analog Front End) 404. The AFE 404 converts the analog image signal output from the image sensor 403 into a digital signal and outputs the digital signal to a DSP (Digital Signal Processor) 405. The DSP 405 performs various image processing, compression / decompression processing, and the like on the digital image signal output from the AFE 404.

  A recording medium 406 records image data processed by the DSP 405. The display unit 407 is configured by an LCD or the like, and displays captured images and various menu screens. The RAM 410 is connected to the DSP 405 and temporarily stores image data and the like. A TG 408 is a timing generator and drives and controls the image sensor 403.

  The temperature detection unit 492 detects the internal temperature of the camera, the posture detection unit 491 detects the posture of the camera, and the blade drive lever detection unit 493 detects the position of the blade drive lever of the focal plane shutter 113. The detection result of each detection unit is output to the CPU 409.

  The lens control unit 494 outputs lens information such as the focal length, the aperture diameter, the exit pupil diameter, and the distance between the exit pupil and the imaging element 403 of the photographing lens 401 to the CPU 409, and the aperture, the lens, and the like according to the control by the CPU 409. Drive.

  The CPU 409 controls the AFE 404, DSP 405, TG 408, shutter drive circuit 411, temperature detection unit 492, posture detection unit 491, blade drive lever detection unit 493, and lens control unit 494.

  Next, the focal plane shutter 113 will be described with reference to FIGS.

  2A is a view of the focal plane shutter 113 viewed from the image sensor 403 side (hereinafter referred to as an image plane side), and FIG. 2B is a view of the focal plane shutter 113 viewed from the subject side. 3A is an exploded perspective view of the focal plane shutter 113 as viewed from the image plane side, and FIG. 3B is an exploded perspective view of the focal plane shutter 113 as viewed from the subject side.

  As shown in FIG. 3B, an auxiliary base plate 52 is attached to the subject side of the shutter base plate 1, and a traveling space for blades is formed between the shutter base plate 1 and the auxiliary base plate 52. Yes. This traveling space is divided into two, a traveling space for the rear blade unit 51 is formed between the shutter base plate 1 and the intermediate plate 54, and between the auxiliary ground plate 52 and the intermediate plate 54, A traveling space for the leading blade unit 50 is formed. The rear blade unit 51 and the front blade unit 50 shield or open an exposure opening described later by a reciprocating operation.

  The spacer 53 a has a function of securing a space between the shaft portion forming the parallel link of the rear blade unit 51 and the shutter base plate 1. The spacer 53 b has a function of securing a space between the shaft portion forming the parallel link of the leading blade unit 50 and the auxiliary base plate 52. The spring 56 is a backlash removing spring for the leading blade unit 50, and the spring 57 is a backlash removing spring for the trailing blade unit 51.

  The shutter base plate 1 and the auxiliary base plate 52 have an aperture opening 1m and an aperture opening 52a having substantially the same shape, and a subject passing through a rectangular exposure opening in which the two aperture openings 1m and 52a are overlapped. Defines the luminous flux. The leading blade slit forming section 50a determines the subject light beam passage start timing at the exposure opening, and the trailing blade slit forming section 51a determines the subject light beam passage end timing at the exposure opening.

  As shown in FIG. 3A, the shutter base plate 1 is provided with a plurality of shafts 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, and 1i. A front drive lever 3, a rear drive lever 4, and a front tension lever 5 are rotatably attached to the shafts 1a, 1b, and 1c, respectively, and a rear tension lever 6 and a front brake are respectively mounted on the shafts 1d, 1e, and 1f. A lever 7 and a rear brake lever 8 are rotatably attached. A charge cam gear 9, a reduction gear 10, and a phase gear 11 are rotatably attached to the shafts 1g, 1h, and 1i, respectively. The front brake lever 7 and the rear brake lever 8 correspond to an example of a brake member of the present invention. The front drive lever 3 and the rear drive lever 4 correspond to an example of the drive member of the present invention.

  A front rotor unit 15 and a rear rotor unit 16 are attached to the intermediate plate 20. The front rotor unit 15 has a function similar to a motor together with the magnetic circuit unit 13, and is an actuator that controls the operation timing of the front drive lever 3. Similarly, the rear rotor unit 16 has a function similar to a motor together with the magnetic circuit unit 14, and is an actuator that controls the operation timing of the rear drive lever 4.

  The electric circuit unit 21 supplies electricity to the magnetic circuit units 13 and 14. The charge motor 12 drives the reduction gear 10. The gear cover 22 is a cover that covers the reduction gear 10 and the phase gear 11 that meshes with the reduction gear 10. The photo interrupter 60 detects the phase of the phase gear 11.

  FIG. 4 is a cross-sectional view of the rear brake lever 8. Various parts constituting the rear brake are held so as to be fixed or rotatable with respect to the shaft 1f. The rear brake lever 8 is pressed by the brake fixing plate 31 while being sandwiched between the pair of brake seats 34. This pressing force is generated by pressing the leaf spring 38 by a predetermined amount with the brake force adjusting member 36. As a result, a frictional force as a drag force is applied to the rear brake lever 8 against the rotation of the rear brake lever 8 about the shaft 1f. The brake seat 34 corresponds to an example of the friction member of the present invention, and the brake fixing plate 31 corresponds to an example of the fixing member of the present invention.

  A brake return spring 33 is provided around the brake force adjusting member 36 so that the movable end of the brake return spring 33 is hooked to the rear brake lever 8 or the brake fixing plate 31 by a switching operation described later. It has become. The brake return spring 33 corresponds to an example of an urging unit of the present invention.

  In the state where the movable end of the brake return spring 33 is hooked on the rear brake lever 8, the spring force of the brake return spring 33 contributes as a brake force during blade travel. If the rear brake lever 8 is to be returned to the standby position (second standby position), the spring force of the brake return spring 33 contributes to assisting charging. Note that the front brake lever 7 has the same configuration as that of the rear brake lever 8, and therefore, in the following description, the same reference numerals are given to the corresponding portions.

  FIG. 5 is a perspective view showing an arrangement state of main drive components in the standby state of the brake. In FIG. 5, the blade driving pin 3 b of the leading drive lever 3 passes through the shutter base plate 1 and is connected to the leading blade unit 50. Further, the blade driving pin 3b abuts on the leading brake lever 7 at the end of blade traveling, and converts the kinetic energy of the leading driving lever 3 into heat energy by the brake seat 34, and at the same time, charges the brake return spring 33 to obtain elastic energy. Also convert to.

  The brake charge pin 3c is attached to the front drive lever 3, and the brake charge pin 3c is in the middle of returning the front drive lever 3 to the standby position (first standby position). Return to the second standby position). At this time, the brake return spring 33 is newly put in order to return the front brake lever 7 to the standby position (second standby position) by releasing the elastic energy accumulated as a brake during blade travel. Energy can be reduced.

  In particular, in the present embodiment, a hooked portion 30 a is formed on the brake fixing plate 30. The hooking portion of the movable end of the brake return spring 33 in the vicinity of the standby position of the front brake lever 7 is hooked on the hooked portion 30 a of the brake fixing plate 30 without being hooked by the front brake lever 7. . As a result, when the front brake lever 7 is positioned in the vicinity of the standby position, the brake return spring 33 does not bias the front brake lever 7.

  On the other hand, in the region excluding the vicinity of the standby position of the front brake lever 7, the movable end of the brake return spring 33 is hooked on the hook portion 7 a of the front brake lever 7. Is energized. Therefore, even if a brake return spring 33 having a strong spring force is used, the strong spring force does not overcome the frictional force and move the front brake lever 7 at the standby position of the front brake lever 7.

  That is, the front brake lever 7 remains in the standby position of the front brake lever 7 until it is driven by the blade driving pin 3b. As a result, the position at which the blade driving pin 3b contacts the leading brake lever 7 varies due to the rotation of the leading brake lever 7, and the possibility of changing the traveling characteristics of the blade can be minimized.

  Increasing the spring force of the brake return spring 33 means increasing the amount of recovery of the kinetic energy used for blade travel as the elastic energy of the brake return spring 33. Then, when the front brake lever 7 is returned to the standby position of the front brake lever 7, the recovered energy is reused. Therefore, the energy newly input when the front brake lever 7 is returned to the standby position of the front brake lever 7 can be reduced, leading to a reduction in the driving load of the charging operation.

  The roller 3d is a cam follower that is operated by a later cam 9a (described later) of the charge cam gear 9 when the earlier drive lever 3 returns from the travel completion position to the standby position. The front brake lever 7 comes into contact with the stopper rubber 39 at the travel completion position of the front brake lever 7.

  The blade drive pin 4 b of the rear drive lever 4 passes through the shutter base plate 1 and is connected to the rear blade unit 51. The blade drive pin 4b contacts the rear brake lever 8 at the end of blade travel, and converts the kinetic energy of the rear drive lever 4 into heat energy by the brake seat 34, and at the same time, charges the brake return spring 33 for elasticity. It also converts to energy.

  A brake charge pin 4c is attached to the rear drive lever 4, and the brake charge pin 4c returns the rear brake lever 8 to the standby position in the course of returning the rear drive lever 4 to the standby position. At this time, the brake return spring 33 releases energy that is newly input to return the rear brake lever 8 to the standby position of the rear brake lever 8 by releasing the elastic energy that has been stored and contributed as a brake during blade travel. Can be small.

  In particular, in the present embodiment, a hooked portion 31 a is formed on the brake fixing plate 31. In the vicinity of the standby position of the rear brake lever 8, the hooking portion of the movable end of the brake return spring 33 is hooked on the hooked portion 31 a of the brake fixing plate 31 without being hooked on the rear brake lever 8. . Thus, when the rear brake lever 8 is positioned in the vicinity of the standby position, the brake return spring 33 does not urge the rear brake lever 8.

  On the other hand, in the region other than the vicinity of the standby position of the rear brake lever 8, the movable end of the brake return spring 33 is hooked on the hook portion 8 a of the rear brake lever 8, so that the brake return spring 33 is moved to the rear brake lever 8. Is energized. Therefore, even if the brake return spring 33 having a strong spring force is used, the strong spring force does not overcome the frictional force at the standby position of the rear brake lever 8 and the rear brake lever 8 is not moved.

  That is, the rear brake lever 8 remains in the standby position of the rear brake lever 8 until it is driven by the blade driving pin 4b. Thereby, the position where the blade driving pin 4b contacts the rear brake lever 8 varies due to the rotation of the rear brake lever 8, and the possibility of changing the traveling characteristics of the blade can be minimized.

  Increasing the spring force of the brake return spring 33 means increasing the amount of recovery of the kinetic energy used for blade travel as the elastic energy of the brake return spring 33. This energy is reused when the rear brake lever 8 is returned to the standby position of the rear brake lever 8. Therefore, when the rear brake lever 8 is returned to the standby position of the rear brake lever 8, a new energy is required to be small, which leads to a reduction in driving load during the charging operation.

  The roller 4d is a cam follower that is operated by a rear cam 9b of a charge cam gear 9 described later when the rear drive lever 4 returns from the travel completion position to the standby position. The rear brake lever 8 abuts against the stopper rubber 40 at the travel completion position of the rear brake lever 8.

  Next, the blade traveling operation of the focal plane shutter 113 will be described with reference to FIGS.

  FIG. 6 is a diagram illustrating a standby state of the focal plane shutter 113. In the state shown in FIG. 6, the leading drive lever 3 receives a driving force in the right turning direction from the driving spring 35, but the bent portion 3 a is locked to the locking portion 5 b of the first tightening lever 5. Stopped in a state. Similarly, the rear drive lever 4 receives a driving force in the right-turning direction from the drive spring 35, but stops in a state where the bent portion 4a is locked to the locking portion 6b of the rear tension lever 6. ing. The drive spring 35 corresponds to an example of a drive source of the present invention.

  The first tension lever 5 and the rear tension lever 6 are urged by a spring in the left-turning direction. The cam portion 15a of the front rotor unit 15 is turned to the left by the magnetic circuit unit 13, but in the standby state, the cam portion 15a is on standby in a state of being biased in the right turning direction by a backlash spring (not shown). The cam portion 16a of the rear rotor unit 16 is turned to the left by the magnetic circuit unit 14, but in a standby state, the cam portion 16a is on standby in a state of being biased in the right turning direction by a backlash spring (not shown).

  FIG. 7 is a view showing a state in which the tension of the front drive lever 3 is released. In the state shown in FIG. 7, the cam portion 15 a of the leading rotor unit 15 turns counterclockwise by the magnetic force generated by the magnetic circuit unit 13 and acts on the actuated portion 5 a of the leading tension lever 5. Turn right. As a result, the locking portion 5b of the first tightening lever 5 is retracted from the rotation trajectory of the bent portion 3a of the first driving lever 3, and the tightening of the first driving lever 3 is released. The right turn is started by the urging force of 35. At the same time, the leading blade unit 50 connected to the leading drive lever 3 starts to operate in the direction in which the leading blade is superimposed.

  FIG. 8 is a view showing a state in which the leading drive lever 3 is in contact with the leading brake lever 7. In the state shown in FIG. 8, the leading drive lever 3 turns right from the state shown in FIG. 7 by the biasing force of the driving spring 35, and the blade driving pin 3 b is in contact with the leading brake lever 7. The front brake lever 7 is in the standby position of FIG. 6, the movable end of the brake return spring 33 is hooked on the hooked portion 30 a of the brake fixing plate 30, and the front brake lever 7 is a spring of the brake return spring 33. Not receiving power.

  FIG. 9 is a diagram illustrating a state in which the leading drive lever 3 is started to be charged by the brake return spring 33. In the state shown in FIG. 9, the leading drive lever 3 further turns right from the state of FIG. 8, the slit forming portion 50a of the leading blade unit 50 is retracted from the exposure opening, and the leading brake lever 7 is It is in a state of turning slightly to the left from the state. Further, the latching portion 7 a of the front brake lever 7 reaches the movable end of the brake return spring 33.

  From FIG. 8 to FIG. 9, the leading drive lever 3 and the leading blade unit 50 are decelerated by the action of the leading brake lever 7, but it is mainly between the leading brake lever 7 and the brake seat 34 that contributes to the deceleration. It is only the friction force to do.

  When the front brake lever 7 further turns counterclockwise, the brake return spring 33 starts to store elastic energy. Increasing the spring force of the brake return spring 33 leads to an increase in the amount of elastic energy recovered.

  That is, the ratio that is converted from the urging force of the drive spring 35 and converted into kinetic energy is reduced to the heat energy that is difficult to recover by the brake seat 34, and the ratio that is converted to recoverable elastic energy is reduced. Can be increased.

  In the conventional configuration in which the brake return spring 33 is applied in the entire operating section of the front brake lever 7, the spring force of the brake return spring 33 exceeds the frictional force of the brake seat 34 so that the front brake lever 7 does not rotate at the standby position. There is no need to set it to such an extent.

  On the other hand, in the present embodiment, in the vicinity of the standby position of the front brake lever 7, as described above, the movable end of the brake return spring 33 is hooked on the hooked portion 30a of the brake fixing plate 30, and the brake is released. The return spring 33 does not act on the tip brake lever 7. As a result, the restriction of the spring force setting of the brake return spring 33 is eliminated, and the spring force can be increased as compared with the conventional case.

  In the present embodiment, the switching position between the action and non-action of the brake return spring 33 with respect to the tip brake lever 7 by the hooked portion 30a is provided at a position after the slit forming portion 50a is retracted from the exposure opening. Thereby, it is possible to make it difficult for re-exposure due to the bounce of the blade, which is a concern when the brake return spring 33 is strengthened.

  FIG. 10 is a diagram illustrating a traveling completion state of the leading blade. In the state shown in FIG. 10, the front brake lever 7 abuts against the stopper rubber 39 and stops turning left, and the front drive lever 3 also stops turning right as the front brake lever 7 stops. The brake return spring 33 is stopped in a state where the movable end is hooked on the hook portion 7a of the front brake lever 7 and is charged by the amount that the front brake lever 7 is turned from the state of FIG.

  The elastic energy charged in the brake return spring 33 is used as energy for returning the leading blade to the standby state, as will be described later. At this time, as described above, the slit forming portion 50a is located outside the exposure opening at a position where the hooked portion of the movable end of the brake return spring 33 is switched from the tip brake lever 7 to the brake fixing plate 30 by the hooked portion 30a. It is provided in the position. For this reason, before the slit forming part 50a reaches the exposure opening, the rear blade pushing by the elastic energy of the brake return spring 33 ends.

  FIG. 11 is a view showing a state where the tension of the rear drive lever 4 is released. In the state shown in FIG. 11, the cam portion 16 a of the rear rotor unit 16 turns left by the magnetic force generated by the magnetic circuit unit 14 and acts on the actuated portion 6 a of the rear tightening lever 6. Turn right. As a result, the locking portion 6b of the rear tightening lever 6 is retracted from the rotation locus of the bent portion 4a of the rear drive lever 4, and the tightening of the rear drive lever 4 is released. The rear drive lever 4 is driven by the drive spring 35. Turn right with the urging force of. At the same time, the rear blade unit 51 connected to the rear drive lever 4 starts to operate in the direction of expanding the rear blade.

  FIG. 12 is a view showing a state in which the rear drive lever 4 is in contact with the rear brake lever 8. In the state shown in FIG. 12, the rear drive lever 4 further turns right from the state shown in FIG. 10 by the urging force of the drive spring 35, and the blade drive pin 4 b is in contact with the rear brake lever 8. The rear brake lever 8 is in the standby position of FIG. 6, the movable end of the brake return spring 33 is hooked on the hooked portion 31 a of the brake fixing plate 31, and the rear brake lever 8 is a spring of the brake return spring 33. Not receiving power.

  FIG. 13 is a diagram showing a state where the rear drive lever 4 starts to be charged by the brake return spring 33. In the state shown in FIG. 13, the rear drive lever 4 further turns right from the state shown in FIG. 12, the slit forming portion 51a of the rear blade unit 51 is retracted from the exposure opening, and the rear brake lever 8 is It is in a state of turning slightly to the left from the state. Further, the latching portion 8 a of the rear brake lever 8 reaches the movable end of the brake return spring 33.

  From FIG. 12 to FIG. 13, the rear drive lever 4 and the rear blade unit 51 are decelerated by the action of the rear brake lever 8, but the contribution to the deceleration occurs mainly between the rear brake lever 8 and the brake seat 34. It is only the friction force to do.

  When the rear brake lever 8 further turns counterclockwise, the brake return spring 33 starts to store elastic energy. Increasing the spring force of the brake return spring 33 leads to an increase in the amount of elastic energy recovered.

  That is, the ratio that is converted from the urging force of the drive spring 35 and converted into kinetic energy is reduced to the heat energy that is difficult to recover by the brake seat 34, and the ratio that is converted to recoverable elastic energy is reduced. Can be increased.

  In the conventional configuration in which the brake return spring 33 is applied over the entire operating section of the rear brake lever 8, the spring force of the brake return spring 33 strikes the frictional force of the brake seat 34 so that the rear brake lever 8 does not rotate at the standby position. It is necessary to set it not to win.

  On the other hand, in the present embodiment, in the vicinity of the standby position, as described above, the movable end of the brake return spring 33 is hooked on the hooked portion 31a of the brake fixing plate 31, and the brake return spring 33 is moved backward. The brake lever 8 is not acted on. As a result, the restriction of the spring force setting of the brake return spring 33 is eliminated, and the spring force can be increased as compared with the conventional case.

  Further, in the present embodiment, the switching position between the action and non-action of the brake return spring 33 with respect to the rear brake lever 8 by the hooked portion 30a is provided at the position after the slit forming portion 51a is retracted from the exposure opening. Thereby, it is possible to make it difficult for re-exposure due to the bounce of the blade, which is a concern when the brake return spring 33 is strengthened.

  FIG. 14 is a diagram illustrating a travel completion state of the rear blade. In the state shown in FIG. 14, the rear brake lever 8 contacts the stopper rubber 40 and stops turning left, and the rear drive lever 4 also stops turning right as the rear brake lever 8 stops. The brake return spring 33 is stopped in a state in which the movable end is hooked to the hooking portion 8a of the rear brake lever 8, and the rear brake lever 8 is charged by the amount of rotation from the state of FIG.

  The elastic energy charged in the brake return spring 33 is used as energy for returning the rear blade to the standby state, as will be described later. At this time, as described above, the position where the hooked portion of the movable end of the brake return spring 33 is switched from the rear brake lever 8 to the brake fixing plate 31 by the hooked portion 31a is such that the slit forming portion 51a is outside the exposure opening. It is provided in the position. For this reason, before the slit forming portion 51a reaches the exposure opening, the rear blade boosting by the elastic energy of the brake return spring 33 is completed.

  Next, with reference to FIG. 15 to FIG. 20, the charging operation of the front drive lever 3 and the rear drive lever 4 from the travel completion state of FIG. 14 to the return to the standby state of FIG. 6 will be described.

  In the state shown in FIG. 14, the traveling completion states of the leading drive lever 3 (leading blade) and the trailing drive lever 4 (rear blade) are detected by the blade driving lever detector 493, respectively. A detection signal from the blade drive lever detection unit 493 is output to the CPU 409, and the CPU 409 starts energizing the charge motor 12 via the shutter drive circuit 411 after a predetermined time has elapsed. As a result, the charge cam gear 9 starts to turn right.

  FIG. 15 is a diagram illustrating a state where charging of the first drive lever 3 is started. In the state shown in FIG. 15, the leading cam 9 a of the charge cam gear 9 is in contact with the roller 3 d attached to the leading drive lever 3. Thereafter, the drive spring 35 is charged by the left turn of the first drive lever 3.

  Further, at the travel completion position, the front drive lever 3 is pushed forward in the left turning direction by the front brake lever 7, but the front drive lever 3 starts the left turn ahead of the front brake lever 7. A gap is generated between the drive lever 3 and the tip brake lever 7. For this reason, the force with which the front drive lever 3 presses the front brake lever 7 is lost. Thus, the front brake lever 7 can release the elastic energy stored in the brake return spring 33.

  FIG. 16 shows the rotation angle of the front brake lever 7, the spring force (torque) of the front brake lever 7, the spring force (torque) of the brake return spring 33, the spring force (torque) of the drive spring 35, and the friction caused by the brake seat 34. It is a graph which shows the relationship with force (torque).

  In the present embodiment, as shown in FIG. 16, the spring force of the brake return spring 33 is set to exceed the frictional force generated by the brake seat 34 at the travel completion position. In addition, the sum of the frictional force generated in the brake seat 34 and the spring force with which the drive spring 35 presses the front brake lever 7 via the drive pin 3b at the travel completion position exceeds the spring force of the brake return spring 33. It is set. For this reason, the brake return spring 33 starts to push back the front brake lever 7 after charging of the front drive lever 3 is started.

  FIG. 17 shows the rotation angle of the front brake lever 7, the spring force (torque) of the front brake lever 7, the spring force (torque) of the brake return spring 33, and the frictional force (torque) of the brake seat 34 in the conventional configuration. It is a graph which shows a relationship.

  Comparing the example of the present invention shown in FIG. 16 with the conventional example shown in FIG. 17, it can be seen that the example of the present invention has a larger elastic energy that can be stored by the brake return spring 33 and released during charging. The rear brake lever 8 is the same as the front brake lever 7.

  FIG. 18 is a diagram illustrating a state in which charging of the first brake lever 7 is started. In the state shown in FIG. 18, the charge cam gear 9 continues to make a right turn from FIG. 15, and the front drive lever 3 further turns to the left by the rear push of the front cam 9 a, and the brake charge pin 3 c catches up with the front brake lever 7. Prior to this, as the front drive lever 3 turns to the left, the front brake lever 7 continues to turn right toward the standby position, but the boosting by the spring force of the brake return spring 33 is also continued.

  Referring to FIG. 16, in the present embodiment, the brake return spring 33 has a spring force less than the frictional force generated by the brake seat 34 immediately before the movable end comes into contact with the hooked portion 30 a of the brake fixing plate 30. It is set as follows. Thereby, further safety can be secured against re-exposure by the leading blade. It is possible to increase the spring force of the brake return spring 33, and it is also possible to set so that the front brake lever 7 is returned to the standby position only by the spring force. In that case, the load applied to the charge motor 12 can be further reduced.

  FIG. 19 is a diagram illustrating a state where charging of the rear drive lever 4 is started. In the state shown in FIG. 19, the charge cam gear 9 further turns right from the state shown in FIG. 18, and the rear cam 9b of the charge cam gear 9 abuts on the roller 4d. Thereafter, the drive spring 35 is charged by the left turn of the rear drive lever 4.

  Further, at the travel completion position, the rear drive lever 4 is pushing in the direction in which the rear brake lever 8 turns left, but the rear drive lever 4 starts turning left before the rear brake lever 8, A gap is generated between the rear drive lever 4 and the rear brake lever 8. For this reason, the force with which the rear drive lever 4 presses the rear brake lever 8 is lost. As a result, the rear brake lever 8 can release the elastic energy stored in the brake return spring 33.

  Further, since the spring force of the brake return spring 33 is set so as to exceed the frictional force generated by the brake seat 34 at the travel complete position, the brake return spring 33 starts to push the rear brake lever 8 back.

  On the other hand, the front drive lever 3 has returned to the vicinity of the standby position, and the front brake lever 7 has also returned to the vicinity of the standby position. The movable end of the brake return spring 33 that has released the elastic energy is switched in position from the hook portion 7a of the brake lever 7 to the hook portion 30a of the brake fixing plate 30, and thereafter, the spring force of the brake return spring 33 is changed. Therefore, the tip brake lever 7 does not move. At this time, the slit forming portion 50a of the leading blade unit 50 does not enter the opening 1m of the shutter base plate 1 (see FIG. 10).

  FIG. 20 is a diagram illustrating a state in which the charge of the first drive lever 3 is completed. In the state shown in FIG. 20, the leading drive lever 3 reaches the position most rotated in the left-handed direction, and the locking portion 5 b of the leading tightening lever 5 is within the rotation locus of the bent portion 3 a of the leading drive lever 3. And it has entered a position that hinders driving.

  FIG. 21 is a diagram showing a state in which charging of the rear brake lever 8 is started. In the state shown in FIG. 21, the charge cam gear 9 continues to make a right turn from the state of FIG. 20, and the rear drive lever 4 further turns to the left by the rear push of the rear cam 9 b, so that the brake charge pin 4 c moves to the rear brake lever 8. catch up. Before this, as the rear drive lever 4 turns left, the rear brake lever 8 continues to turn right toward the standby position, but the back-pushing by the spring force of the brake return spring 33 is also continued.

  In the present embodiment, the brake return spring 33 is set so that the spring force is less than the frictional force generated by the brake seat 34 before the movable end comes into contact with the hooked portion 31 a of the brake fixing plate 31. Thereby, further safety can be secured against re-exposure by the rear blade. However, the spring force of the brake return spring 33 can be increased, and the rear brake lever 8 can be set to return to the standby position with only the spring force. In that case, the load applied to the charge motor 12 can be further reduced.

  FIG. 22 is a diagram illustrating a state in which charging of the rear drive lever 4 is completed. The rear drive lever 4 reaches the most rotated position in the counterclockwise direction, and the latching portion 6b of the rear tightening lever 6 enters the rotation trajectory of the bent portion 4a of the rear drive lever 4 and enters a position that hinders traveling. ing. At this time, the charge cam gear 9 does not hold the rear drive lever 4, and the locking portion 6 b of the rear tightening lever 6 locks the rear drive lever 4.

  When the charge cam gear 9 continues to rotate by energization of the charge motor 12 and the photo interrupter 60 detects the switching of the light shielding state by the phase of the phase gear 11, the CPU 409 passes through the shutter drive circuit 411 to the charge motor 12. Stop energization. Thereby, it will be in the standby state of FIG. At this time, the charge cam gear 9 does not hold the rear drive lever 4, and the locking portion 6 b of the rear tightening lever 6 locks the rear drive lever 4.

  As described above, in the present embodiment, even when the spring force of the brake return spring 33 exceeds the frictional force of the brake seat 34 as the braking force of the driving unit of the blade group, the braking start timing of the brake is stabilized, It is possible to reduce the load when charging the blade group.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

DESCRIPTION OF SYMBOLS 1 Shutter base plate 3 Front drive lever 4 Rear drive lever 5 First tightening lever 6 Rear tightening lever 7 Rear brake lever 8 Rear brake lever 30a, 31a Engagement part 30, 31 Brake fixing plate 33 Brake return spring 34 Brake seat 35 Drive spring 50 Leading blade unit 50a, 51a Slit forming portion 51 Rear blade unit 113 Focal plane shutter

Claims (5)

A driving member that drives the blade group in a direction in which the blade group shields or opens the exposure opening by traveling from the first standby position to the first travel completion position;
A drive source for causing the drive member to travel toward the first travel completion position;
When the drive member contacts before reaching the first travel completion position, the drive member travels from the second standby position to the second travel completion position, so that the drive member moves to the first travel completion position. A brake member that decelerates traveling toward the vehicle,
Urging means for urging the brake member toward the second standby position,
When the brake member is positioned at the second standby position, the urging means does not urge the brake member, and the blade group is driven by the driving member, thereby forming slits in the blade group. The shutter device is characterized in that the urging means urges the brake member after the portion reaches the outside of the exposure opening. A friction member that applies a frictional force to the brake member when the brake member travels toward the second travel completion position;
A fixing member for fixing the friction member,
2. The shutter device according to claim 1, wherein when the brake member is positioned at the second standby position, the biasing unit biases the fixing member without biasing the brake member. .   When the brake member is located at the second standby position, the friction force exceeds the urging force of the urging means, and when the brake member is located at the second travel completion position, the urging means. The shutter device according to claim 2, wherein an urging force of the shutter exceeds the frictional force.   When the brake member is located at the second travel completion position, the urging force of the urging means is such that the drive source drives the drive member to the first travel completion position and the frictional force. The shutter device according to claim 2, wherein the shutter device is less than a total of the shutter device.   An imaging apparatus comprising the shutter device according to claim 1.