JP6507408B2 - Zoom lens barrel and optical device - Google Patents

Description

  The present invention relates to a zoom lens barrel and an optical apparatus.

  2. Description of the Related Art Zoom lens barrels having a plurality of lens groups and performing zooming by receiving a predetermined zooming operation (for example, a user operation for rotating a zooming operation ring) have been widely used. Such a zoom lens barrel, in particular, a high magnification zoom lens barrel, is hung from a shoulder or a neck by a strap or the like attached to the camera body while the photographer mounts the zoom lens barrel on the camera body, for example When carrying the camera, the zoom mechanism may be driven by its own weight and the zoom lens barrel may be extended. If the zoom lens barrel is extended while the photographer is not aware of it, the lens barrel may be damaged due to collision with an obstacle or the like.

  In order to prevent the extension of the zoom lens barrel due to its own weight, for example, Patent Document 1 discloses a zoom lens barrel provided with a fixed barrel and a movable barrel movable in the optical axis direction with respect to the fixed barrel. Discloses a zoom lens barrel capable of locking movement of the movable barrel relative to the fixed barrel by providing a notch in the movable barrel and engaging a lock member provided in the fixed barrel with the notch. It is done.

JP 10-104495 A

  Here, in the invention described in Patent Document 1, the movement of the movable cylinder relative to the fixed cylinder is mechanically locked by engaging the lock member in the notch, and therefore, the lock member and the notch wear out. There was a problem that it would not be possible to lock the lock firmly when the etc. occurred.

  In the invention described in Patent Document 1, the movement of the movable barrel with respect to the fixed barrel can only be locked at the wide-angle end (that is, the state where the barrel is contracted the most). At the time of telephoto, the movement of the movable cylinder with respect to the fixed cylinder could not be locked.

  The present invention has been made in view of the above-described needs, and has an object of providing a zoom lens barrel capable of preventing a locking failure due to wear or the like in a mechanism for suppressing the drive of the zoom mechanism.

  The zoom lens barrel according to the present invention is a lock that switches between a zoom mechanism that performs zooming by receiving a predetermined zooming operation, a locked state that suppresses driving of the zoom mechanism by electromagnetic force, and an unlocked state that does not suppress driving of the zoom mechanism. And a switching mechanism.

  According to the present invention, since the lock switching mechanism can switch between the locked state and the unlocked state of the zoom mechanism by utilizing the electromagnetic force, there is no mechanical deterioration such as wear in the lock switching mechanism, and the lock can be locked. It is possible to prevent the failure and to prevent the zoom mechanism from being driven at a timing not intended by the user in the locked state. Further, according to the present invention, since the locked state and the unlocked state can be switched by the electromagnetic force, the zoom mechanism can be brought into the locked state in a desired telephoto state.

In the present invention, the lock switching mechanism preferably includes a coil and a magnet, and switches between the locked state and the unlocked state depending on whether the coil is in a short circuit state or an open state.
According to the present invention having such a configuration, the zoom mechanism can be switched between the locked state and the unlocked state by switching the coil between the short circuit state and the open state, and the zoom mechanism is locked without requiring power. can do.

In the present invention, it is preferable that the lock switching mechanism lock the zoom mechanism in the short circuit state.
According to the present invention having such a configuration, since the short brake state occurs when the coil is in the short circuit state, the zoom mechanism can be locked.

In the present invention, it is preferable that the lock switching mechanism lock the zoom mechanism by the back electromotive force generated in the coil in the short circuit state.
According to the present invention having such a configuration, by switching to the short circuit state, a back electromotive force is generated in the coil by the magnetic field of the coil, so that the lock state can be set to suppress the drive of the zoom mechanism. By switching to the above, no back electromotive force is generated, so it is possible to set the lock release state in which the drive of the zoom mechanism is not suppressed.

In the present invention, the lock switching mechanism is preferably a motor including a coil and a magnet.
According to the present invention having such a configuration, since the drive of the zoom mechanism can be suppressed by shorting the motor, a power supply or the like is not required.

In the present invention, the motor is preferably a brushless motor.
According to the present invention having such a configuration, the brushless motor can change the resistance to the rotation of the rotation shaft of the motor to a desired value, so, for example, adjusting the resistance according to the operation of the zoom mechanism. By this, the resistance to the zoom operation can be made constant, and a better feeling of operation can be provided.

In the present invention, the lock switching mechanism preferably switches between the locked state and the unlocked state according to whether the lock switching mechanism is in the energized state or in the non-energized state.
According to the present invention having such a configuration, it is possible to switch electrically between the locked state and the unlocked state depending on whether the current is in the energized state or not.

In the present invention, it is preferable that the lock switching mechanism lock the zoom mechanism in the non-energized state.
In many cases, when the lock switching mechanism is in the locked state, the zoom lens barrel and an optical device such as a camera are not driven, for example, when moving. On the other hand, according to the present invention having such a configuration, when the lock switching mechanism is in the unlocked state, optical devices such as the zoom lens barrel and the camera are driven, and these power supplies are used. This eliminates the need for a new power supply. In addition, since the lock switching mechanism is energized only when the optical device is used, necessary power can be suppressed.

Further, in the present invention, the lock switching mechanism has a fluid whose viscosity changes between the energized state and the non-energized state, and changes the viscosity of the fluid between the energized state and the non-energized state to unlock and release the lock. It is preferable to switch between the states.
According to the present invention having such a configuration, since the locked state and the unlocked state are switched by changing the viscosity of the fluid between the energized state and the non-energized state, it is possible to avoid problems such as wear of members. .

Further, in the present invention, it is preferable that the fluid has a low viscosity in the energized state and a high viscosity in the non-energized state. Also, in the present invention, the fluid is preferably an MR fluid.
According to the present invention having such a configuration, the viscosity of the fluid can be increased in the non-energized state and the locked state can be established, so that the locked state can be established without the need for electric power. In addition, there is no need to provide a new power supply.

  An optical apparatus according to the present invention includes the zoom lens barrel described above.

  According to the present invention, it is possible to provide a zoom lens barrel capable of preventing a lock failure due to wear or the like in a mechanism for suppressing the drive of the zoom mechanism.

The structure of the single-lens reflex camera by 1st Embodiment of this invention is shown, and the state at the time of a wide angle is shown. The structure of the single-lens reflex camera by 1st Embodiment of this invention is shown, and the state at the time of a telephoto is shown. The structure of the lock switching mechanism of the zoom lens barrel by 1st Embodiment of this invention is shown, and a locked state is shown. The structure of the lock switching mechanism of the zoom lens barrel by 1st Embodiment of this invention is shown, and a lock release state is shown. The modification of the structure of the lock switching mechanism of the zoom lens barrel by 1st Embodiment of this invention is shown, and a lock release state is shown. The structure of the lock switching mechanism of the zoom lens barrel by 2nd Embodiment of this invention is shown, and a lock release state is shown. FIG. 10 is a view showing the configuration of a lock switching mechanism of a zoom lens barrel according to a third embodiment of the present invention, and shows a unlocked state.

First Embodiment
Hereinafter, a first embodiment of a zoom lens barrel and an optical apparatus according to the present invention will be described in detail with reference to the drawings. In the following description, the case where the present invention is applied to a single-lens reflex camera as an optical device will be described.

  1 and 2 show the configuration of the single-lens reflex camera 1 according to the present embodiment, and FIG. 1 shows the wide-angle state and FIG. 2 the telephoto state. As shown in FIGS. 1 and 2, the single-lens reflex camera 1 of the present embodiment is configured by mounting a zoom lens barrel 10 on a camera body 2 having an imaging element.

  The zoom lens barrel 10 is, for example, a high magnification telephoto lens having a focal length of 16 to 300 mm, and the first movable barrel housed in the fixed barrel 12 and the fixed barrel 12 connected to the camera body via a mount. And a second moving cylinder 16 accommodated in the first moving cylinder 14. One or more lens groups (not shown) are held inside the fixed barrel 12, the first movable barrel 14, and the second movable barrel 16 via mounting frames.

  The zoom lens barrel 10 has an annular zoom ring 18 (zoom mechanism) attached to the outer periphery of the fixed barrel 12 and a cam mechanism linked to the zoom ring 18. When the photographer rotates the zoom ring 18 in a predetermined direction with respect to the fixed barrel 12, the first moving barrel 14 is extended in the optical axis direction relative to the fixed barrel 12 by the cam mechanism, and the second movement is performed. The barrel 16 is extended relative to the first movable barrel 14 to increase the overall length of the barrel. With the movement of the first movable barrel 14 and the second movable barrel 16, the positional relationship between the lens units is changed, and the wide-angle state is changed to the telephoto state.

  Further, by rotating the zoom ring 18 in the direction opposite to the predetermined direction with respect to the fixed barrel 12, the first moving barrel 14 is retracted toward the fixed barrel 12 by the cam mechanism, and the second movable barrel 16 retreats toward the first movable barrel 14 to shorten the overall length of the barrel. With the movement of the first movable barrel 14 and the second movable barrel 16, the positional relationship between the lens units is changed, and the telephoto state is changed to the wide-angle state. That is, the zoom lens barrel 10 of the present embodiment can perform zooming (optical zooming) by performing a predetermined zooming operation (rotation operation) on the zoom ring 18.

  As a cam mechanism for advancing and retracting the first movable cylinder 14 and the second movable cylinder 16 with respect to such a fixed cylinder 12, a conventionally known mechanism can be adopted. Further, in the present embodiment, a zoom lens barrel having two movable barrels will be described, but the present invention is not limited to this, and the present invention is also applied to a zoom lens barrel having one or three or more movable barrels. it can. Further, in the present embodiment, the configuration in which the total length of the lens barrel is increased when changing from the wide angle state to the telephoto state has been described as an example, but the present invention is not limited to this. For example, the entire length of the lens barrel may be shortened when changing from the wide-angle state to the telephoto state, or may not be changed when changing from the wide-angle state to the telephoto state. It may be

  Furthermore, the zoom lens barrel 10 of the present embodiment has the weight of the zoom lens barrel 10 (more specifically, the first movable barrel 14 and the lens group held by the first movable barrel 14, and the second A lock switching mechanism 20 for preventing expansion and contraction due to the movable barrel 16 and the lens group held by the first movable barrel 16 is provided. 3 and 4 are diagrams showing the configuration of the lock switching mechanism 20 in the zoom lens barrel 10 of the present embodiment, FIG. 3 shows a locked state, and FIG. 4 shows an unlocked state. As shown in FIGS. 3 and 4, the lock switching mechanism 20 includes a circuit 24 including a motor 22 and a switch 26, a first gear 30 attached to a rotation shaft 22 A of the motor 22, and a first gear 30. , And a third gear 36 connected via the second gear 32 and the shaft 34, and an internal gear attached to the inside of the zoom ring 18 and meshing with the third gear 36. And 38. The first gear 30 has a smaller number of teeth than the second gear 32, and the first gear 30 and the second gear 32 constitute a reduction gear 28. With this configuration, the rotational force of the zoom ring 18 is transmitted to the rotation shaft 22A of the motor 22 through the reduction gear 28, and the resistance against the rotational force generated on the rotation shaft 22A of the motor 22 is reduced through the reduction gear 28. And transmitted to the zoom ring 18.

  In the present embodiment, a small DC motor is used as the motor 22. The motor 22 has a coil 22C connected to the rotation shaft 22A and a magnet 22B disposed around the coil 22C. The circuit 24 includes a switch 26, and electric wires extending from both poles of the switch 26 are connected to a pair of brushes 22 D of the motor 22. The coil 22C is connected to the pair of commutators 22E, and when the coil 22C rotates, each commutator 22E alternately contacts each of the pair of brushes 22D.

  As shown in FIG. 3, by closing the switch 26 (turning on the switch), the circuit 24 is shorted and the motor, ie, the coil 22C is shorted. At this time, when the zoom ring 18 tries to rotate, and the coil 22C of the motor 22 tries to rotate in the magnetic field generated by the magnet 22B, the magnetic flux changes in the coil 22C. When a change in magnetic flux occurs in the coil 22C in this manner, a back electromotive force is generated by electromagnetic induction. The counter electromotive force generates a force that prevents the rotation in the direction opposite to the direction in which the coil 22C is used for rotation, and acts as a braking force (hereinafter, such a brake is referred to as a short brake). As described above, when the switch 26 is closed, a braking force acts on the rotation shaft 22A of the motor 22, and the rotation shaft 22A can not rotate unless a force exceeding a predetermined rotation force acts. The braking force generated on the rotation shaft 22A of the motor 22 is transmitted to the zoom ring 18 via the reduction gear 28. Thus, the lock switching mechanism 20 switches to the locked state which suppresses the drive of the zoom mechanism by closing the switch 26, that is, setting the lock switching mechanism 20 to the short-circuited state. The driving of the zoom mechanism includes not only movement of the zoom mechanism by its own weight, but also movement of the zoom mechanism by zoom operation by the user and movement of the zoom mechanism by vibration.

  As shown in FIG. 4, when the switch 26 is opened (when the switch is turned off), the coil 22C also becomes an open state motor and the short brake is released. Thus, the rotary shaft 22A of the motor 22 can be rotated with almost no load applied. Thus, by opening the switch 26, the zoom ring 18 can be rotated (unlocked state) without being restricted in driving.

  In the present embodiment, the switching between the ON and OFF of the switch 26, that is, the switching between the locked state and the unlocked state of the lock switching mechanism 20, is specifically a zoom lock operation provided on the lens appearance. It is realized by a switch (hereinafter, also simply described as “operation switch”). For example, when the operation switch is turned on, the lock switching mechanism 20 is locked, and when the operation switch is turned off, the lock switching mechanism 20 is unlocked.

  Further, as described later, for example, when the single-lens reflex camera 1 is placed in a posture in which the zoom lens barrel 10 faces upward or downward, a rotational force acts on the zoom ring 18 by the weight of the movable barrels 14 and 16. . The gear ratio of the reduction gear 28 is amplified by the reduction gear 28 and transmitted to the zoom ring 18. The zoom ring 18 generates resistance due to the weight of the movable cylinders 14 and 16 that is generated on the rotation shaft 22 A of the motor 22 in the short brake state. It is set to be larger than the torque of.

  Hereinafter, in the single-lens reflex camera 1 described above, when carrying the single-lens reflex camera 1 in a state in which the zoom lens barrel 10 is zoomed to a desired telephoto state, a method of locking the expansion and contraction of the zoom lens barrel 10 will be described. .

  During normal use, the switch 26 is opened as described with reference to FIG. As described above, when the switch 26 is opened, the short brake of the motor 22 is released, and the rotation shaft 22A of the motor 22 can be rotated with almost no load applied. In this state, by rotating the zoom ring 18, the first movable barrel 14 and the second movable barrel 16 can be advanced or retracted with respect to the fixed barrel 12 to zoom to a desired telephoto state.

  Next, when locking in a zoom state to a desired telephoto state, the switch 26 is closed as described with reference to FIG. As described above, closing the switch 26 causes the motor 22 to be in the short brake state, and a resistance acts when trying to rotate the rotary shaft 22A. Then, the resistance is increased by the reduction gear 28 and transmitted to the zoom ring 18.

  Therefore, for example, the single-lens reflex camera 1 is in a state where the zoom lens barrel 10 faces downward, and a rotational force acts on the zoom ring 18 by the weight of the first movable barrel 14 and the second movable barrel 16. However, the zoom ring 18 is prevented from rotating by the above-described resistance. Thus, the zoom lens barrel 10 can be prevented from extending due to the weight of the first movable barrel 14 and the second movable barrel 16.

  In addition, even when the single-lens reflex camera 1 is in a state where the zoom lens barrel 10 faces upward, in the same manner, a resistance is transmitted to the zoom ring 18, so the zoom lens barrel 10 is It is possible to prevent the first moving cylinder 14 and the second moving cylinder 16 from being contracted by their own weights.

  Even when the switch 26 is closed as described above, the zooming operation can be performed by applying a rotational force larger than the resistance by the motor 22 to the zoom ring 18.

  As described above, according to the single-lens reflex camera 1 of this embodiment, when the coil 22C of the motor 22 is opened by opening the switch 26, the short brake of the motor 22 is released. The zoom ring 18 has no resistance, but when the coil 22C of the motor 22 is short-circuited by closing the switch 26, a resistance to the rotation acts on the zoom ring 18 due to the short brake. Do. For this reason, even when the zoom lens barrel 10 is in a desired telephoto state, the single-lens reflex camera 1 is directed upward or downward to zoom by the weight of the first movable cylinder 14 and the second movable cylinder 16. Even if a rotational force acts on the ring 18, closing the switch 26 prevents the zoom ring 18 from being resisted and rotated. Thus, it is possible to prevent the movement of the first movable barrel 14 and the second movable barrel 16 with respect to the fixed barrel 12 in a desired telephoto state of the zoom lens barrel 10.

  In the present embodiment, the coil 22C of the motor 22 is short-circuited to apply a load to the zoom ring 18 by electromagnetic force. For this reason, mechanical deterioration such as wear does not occur in the lock switching mechanism, and it is possible to prevent the locking failure and to prevent the zoom ring 18 from being driven at a timing not intended by the user in the locked state.

  Further, in the present embodiment, since the load is applied to the zoom ring 18 by putting the motor 22 in the short brake state, the drive of the zoom ring 18 can be suppressed without requiring power.

  Furthermore, in the present embodiment, the rotation of the zoom ring 18 is not mechanically fixed, and a resistance is applied by the short brake of the motor 22. Therefore, even by the locked state, a large force is applied to the zoom ring 18 A zoom operation is possible. This is due to the weight of the zoom lens barrel 10, even when shooting with a camera such as astronomical shooting facing upward or when shooting with a camera pointing downward, such as when shooting from below a high place, etc. This is effective because the telephoto state does not change.

  The single-lens reflex camera of the present invention is not limited to the above embodiment. For example, a brushless motor can be used as the motor. As described above, by using a brushless motor as the motor 22, the resistance to the rotation of the rotation shaft 22A of the motor 22 can be changed to a desired value.

  Usually, in a zoom lens barrel provided with a plurality of lens groups, a plurality of movable barrels are driven with respect to a fixed barrel so that the rotation of the zoom ring 18 and the magnification become substantially proportional. However, the magnification and the positional relationship between the plurality of fixed cylinders do not necessarily have a proportional relationship, and the relationship between the rotation angle of the zoom ring and the moving distance of the movable cylinder differs between the telephoto state and the wide angle state. Therefore, in the conventional zoom lens barrel, there is a problem that the resistance to the rotation operation when rotating the zoom ring is different in the telephoto state and the wide angle state.

  On the other hand, if a brushless motor is used as the motor 22, the resistance to the rotation of the rotary shaft 22A of the motor 22 can be changed to a desired value, so that the resistance is adjusted according to the rotation of the zoom ring. Thus, for example, the resistance to the rotation operation applied to the zoom ring 18 can be made constant, and a better operation feeling can be provided.

  Further, in the present embodiment, in the unlocked state, the switch 26 is opened and only the short brake of the motor 22 is released. For example, as shown in FIG. 5, the first gear 30 and the second gear The gear 32 may be disengaged. In this case, the switch 26 need not be opened.

  In the first embodiment described above, the motor and the coil are incorporated. However, regardless of this, the coil and the magnet are disposed at appropriate positions, and the magnet is shorted. It is sufficient that the back electromotive force is generated in the circuit connected to the coil by the magnetic field of.

Second Embodiment
Further, the mechanism for switching between the locked state and the unlocked state of the zoom mechanism is not limited to the motor, and it suffices to be able to switch between the state in which the drive of the zoom mechanism is suppressed and the state in which the drive of the zoom mechanism is not suppressed. It is possible to use a fluid such as MR fluid whose viscosity changes between the energized state and the non-energized state. Hereinafter, a second embodiment in which an MR fluid is used as a mechanism for suppressing the drive of the zoom mechanism will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

  FIG. 6 shows the configuration of the lock switching mechanism of the zoom lens barrel 110 of the second embodiment, and shows the unlocked state. As shown in FIG. 6, the lock switching mechanism 24 included in the zoom lens barrel 110 of the second embodiment is provided with a load applying device 122 instead of the motor 22 of the first embodiment, and the circuit 124 is added to the switch 126. The second embodiment differs from the first embodiment in that a power supply 127 is provided. The power source 127 can also be used as a power source for driving a motor or the like for focusing the lens.

  The load applying device 122 includes a housing 122D, an MR fluid 122E filled in the housing 122D, a rotating shaft 122A, a plurality of blade members 122B attached to the rotating shaft 122A, and a pair provided in the housing 122D. And an electrode 122C of

  An opening is formed in the housing 122D, and one end of the rotation shaft 122A protrudes outward of the housing 122D through the opening. A first gear 30 is attached to an end of the rotation shaft 122A that protrudes to the outside.

  The plurality of blade members 122B are plate-like members, and are attached to the outer circumference of the portion of the rotary shaft 122A in the housing 122D at predetermined angular intervals. The number and size of the blade members 122B may be set according to the load required to lock the zooming operation, and is not particularly limited.

  A wire extending from the switch 126 is connected to one electrode 122C of the load application device 122, and an electrode extending from the power source 127 is connected to the other electrode 122C. By closing the switch 126, a potential difference is generated between the pair of electrodes 122C to generate a magnetic field.

  The MR fluid 122E is a fluid containing magnetic particles. In the MR fluid 122 E, the magnetic particles are attracted to each other in a state where no magnetic force is applied, and the viscosity is high due to random bonding, but when the magnetic force is applied, the magnetic particles are aligned in a predetermined direction. It is a fluid that has low resistance (viscosity).

  To lock the loading device 122, the switch 126 of the circuit 124 is opened. As a result, the load application device 122 is de-energized, and no magnetic force acts in the housing 122D. Therefore, when it is attempted to rotate the rotation shaft 122A of the load application device 122, a resistance force acts on the blade-like member 122B due to the viscosity of the MR fluid 122E. Thus, in the state where the switch 126 is opened, the rotation shaft 122A of the load application device 122 can not be rotated unless a force equal to or greater than a predetermined rotational force acts. The resistance generated on the rotation shaft 122A of the load application device 122 is transmitted to the zoom ring 18 via the reduction gear 28. As described above, when the switch 126 is in the closed state, that is, when the lock switching mechanism 24 is in the energized state, the lock switching mechanism 24 is in the locked state in which the driving of the zoom mechanism is suppressed.

  On the other hand, in order to bring the load applying device 122 into the unlocked state, the switch of the circuit 124 is closed. As a result, the load applying device 122 is de-energized, and a magnetic field is generated in the housing 122D. As described above, when the magnetic field is generated in the housing 122D, even if the blade-like member 122B rotates around the rotation shaft 122A, almost no resistance by the MR fluid 122E acts on the blade-like member 122B. Thereby, the rotating shaft 122A of the load application device 122 can be rotated with almost no load applied. As described above, when the switch 126 is in the open state, that is, when the lock switching mechanism 24 is in the non-energized state, the lock switching mechanism 24 is in the unlocked state in which the driving of the zoom mechanism is not suppressed.

  In addition, although the case where MR fluid was used was described in the present embodiment, the fluid is not limited to this, and any fluid may be used as long as the viscosity changes between the energized state and the non-energized state.

Also in the second embodiment, the same effect as that of the first embodiment can be obtained.
Further, the lock switching mechanism of the second embodiment is also in the locked state at the time of non-energization, so that a power source such as a motor for focusing the lens can be shared as a power source for unlocking. There is no need to provide a power supply.
Further, in the second embodiment, by changing the viscosity of the MR fluid 122E between the energized state and the non-energized state, the locked state and the unlocked state are switched, so that problems such as wear of members can be avoided.

Embodiment 3
In the first and second embodiments described above, the case where zooming is performed by rotating the zoom ring 18 has been described, but the present invention is not limited to such an embodiment.

  FIG. 7 is a view showing the configuration of the lock switching mechanism of the zoom lens barrel 210 according to the third embodiment of the present invention, and shows the unlocked state. In the zoom lens barrel 210 according to the third embodiment, the positional relationship between the lens units is changed by an operation of pulling out the movable barrel 214 toward the subject or pushing the movable barrel 214 toward the imaging side while holding the fixed barrel 212. The wide-angle state is changed to the telephoto state. That is, the zoom lens barrel 210 of the present embodiment can perform zooming (optical zooming) by expanding and contracting the movable barrel 214 in the optical axis direction.

  As in the first embodiment, the lock switching mechanism 220 of the zoom lens barrel 210 of the present embodiment includes the circuit 24 including the motor 22, the first gear 30 attached to the rotation shaft 22A of the motor 22, and And a third gear 36 connected via the second gear 32 and the shaft 34. Further, in the lock switching mechanism 220 of the zoom lens barrel 210 of the third embodiment, the pinion 238 is provided on the outer peripheral surface of the movable barrel 214, and the third gear 36 meshes with the pinion 238. Also in the present embodiment, the first gear 30 has a smaller number of teeth than the second gear 32, and the first gear 30 and the second gear 32 constitute a reduction gear 28.

  Also in the present embodiment, closing the switch 26 brings the motor 22 into an energized state, and brings the rotating shaft 22A into a short brake state in which a resistance against rotational force acting from the outside is generated. The resistance is amplified by the reduction gear 28 and transmitted from the third gear 36 to the pinion 238. Therefore, even if it is attempted to move the movable cylinder 214 to the object side or the image forming side with respect to the fixed cylinder 212 by closing the switch 26, the movable cylinder 214 is moved unless a force larger than a predetermined magnitude is applied. In other words, the zoom mechanism is in a locked state in which the drive of the zoom mechanism is suppressed.

  Further, by opening the switch 26, the motor 22 is de-energized, and the short brake is released. Therefore, by opening the switch 26, the movable barrel 214 can be easily moved to the object side or the imaging side with respect to the fixed barrel 212, that is, the unlocking state in which the driving of the zoom mechanism is not suppressed. It can be done.

  In the present embodiment, the present invention is applied to a single-lens reflex camera. However, the present invention is not limited to this. The present invention is applicable to an optical apparatus provided with a zoom lens barrel such as a mirrorless camera or a video camera. Can be applied.

1 single lens reflex camera 2 camera body 10, 110, 210 zoom lens barrel 12, 212 fixed barrel 14 first movable barrel 16 second movable barrel 18 zoom ring 20, 220 lock switching mechanism 22 motor 22A rotary shaft 22B magnet 22C Coil 22D Brush 22E Commutator 24, 124 Circuit 26, 126 Switch 28 Reducer 30 First gear 32 Second gear 34 Shaft 36 Third gear 38 Internal gear 122 Load application device 122A Rotation shaft 122B Blade member 122C Electrode 122D housing 122E MR fluid 127 power supply 214 moving cylinder 238 pinion

Claims (4)

A zoom mechanism that receives a predetermined zooming operation and performs zooming;
A lock switching mechanism that switches between a locked state in which the driving of the zoom mechanism is suppressed by electromagnetic force and a unlocked state in which the driving of the zoom mechanism is not suppressed;
Equipped with
The lock switching mechanism is
Switching between the locked state and the unlocked state according to whether the lock switching mechanism is in the energized state or the non-energized state;
A zoom lens barrel characterized in that the zoom mechanism is in the locked state in a non-energized state . A zoom mechanism that receives a predetermined zooming operation and performs zooming;
A lock switching mechanism that switches between a locked state in which the driving of the zoom mechanism is suppressed by electromagnetic force and a unlocked state in which the driving of the zoom mechanism is not suppressed;
Equipped with
The lock switching mechanism is
It has a fluid whose viscosity changes between energized and de-energized states,
Switching the locked state and the unlocked state by changing the viscosity of the fluid between the energized state and the de-energized state ;
The fluid is
The viscosity decreases in the energized state,
The viscosity increases in the non-energized state,
A zoom lens barrel characterized by The fluid is an MR fluid,
The zoom lens barrel according to claim 2 . An optical apparatus comprising the zoom lens barrel according to any one of claims 1 to 3 .

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