JP2000206396A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute manual focusing only by rotation of a manual focus operating ring by connecting a manual focus operating member and a driving mechanism to each other only at the time of operating the manual focus operating member. SOLUTION: When a manual focus operating ring 26 is manually rotated about an optical axis, the rear end 18d of a clamping lever 18 is driven in one of circumferential directions. As friction torque is generated in a space up to a cover cylinder 23 in a torque ring 21, a guide lever 19 is left behing at the beginning, so that the clamping lever 18 is turned around an eccentric pin 30 to strongly clamp a float ring 16 from front and back by the bending part 18a (18b) and a bent part 19a of a guide lever 19. Whereupon, according to the rotation of a manual focus operating ring 26, the torque ring 21 is rotated in the same direction resisting the friction torque, and further the rotary operation of the manual focus operating ring 26 is transmitted to a rotary cam cylinder 13 through a float ring 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a switching mechanism between a manual focus operation and an automatic focus operation.

[0002]

2. Description of the Related Art Conventionally, SLR (single-lens res
In an interchangeable lens of a flex camera (single-lens reflex camera), a lens barrel capable of performing both a manual focus operation and an automatic focus operation has become mainstream. In the past, in the past, a manual focus operation ring provided around the lens barrel and manually rotated around the optical axis in such a lens barrel automatically rotates in conjunction with the auto focus operation. Had a configuration.

[0003] For this reason, if the user grips the manual focus operation ring at that time, there has been a problem that the user takes his hand for the rotation operation or the autofocus operation is hindered. In order to prevent this, the manual focus operation ring is provided at a position where it is difficult to operate (a position where the hand is difficult to touch), or a cap etc. is put on the manual focus operation ring during auto focus operation so that the hand does not touch The design has been done.

[0004] However, such a design imposes a difficulty in operation on a user who frequently uses manual focus, and has been a factor of reducing the attractiveness of the product. Therefore, conventionally, switching between auto focus and manual focus is performed by moving a manual focus operation ring back and forth and switching a clutch incorporated in a part of gear interlocking,
There has been proposed a configuration in which a changeover switch separately provided on a lens barrel is slid and a clutch is switched in conjunction therewith.

Further, as described in Japanese Patent Application Laid-Open No. 2-253210, a manual operation member (manual focus operation ring) and a power transmission member are provided so as to sandwich a spherical rolling element fitted to the rotating ring member. A structure having a differential mechanism has been proposed. This is a configuration in which the manual operation member is manually rotated during the manual focus operation, the power transmission member is rotated by the motor during the auto focus operation, the rotating ring members are driven via the spherical rolling elements, and the optical system is extended. There is a mechanism in which manual focus and auto focus are switched naturally without being influenced by each other.

[0006]

However, in the configuration for switching the clutch as described above, the switching between the auto focus and the manual focus requires
Some sort of switching operation is eventually required on the lens barrel side separately from the camera body side. Also, as described in JP-A-2-25 / 1990
In the configuration described in Japanese Patent No. 3210, the manual operation member can be operated with approximately one-half of a general force, but the operation amount is approximately doubled, so that an extra rotation operation is performed accordingly. Alternatively, it is necessary to narrow the range of the photographing distance, and the operability deteriorates. In addition, if the lead of the cam that feeds out the optical system is increased to correct this, an excessive force is applied to the drive mechanism.

In view of these problems, the present invention does not require any switching operation between auto focus and manual focus on the lens barrel side, and does not rotate the manual focus operation ring during auto focus operation. It is an object of the present invention to provide a lens barrel with good operability, in which manual focusing can be performed only by rotating a manual focusing operation ring during operation.

[0008]

In order to achieve the above object, according to the present invention, there is provided a focusing optical system, a driving mechanism for driving the focusing optical system, and a predetermined driving mechanism for driving the auto focusing operation. A driving force transmitting mechanism for transmitting a driving force from a source, and a manual focus operating member for manually applying a driving force to the driving mechanism during a manual focus operation, wherein the manual focus operation is performed only when the manual focus operating member is operated. A configuration is provided in which a clutch member that connects the member and the drive mechanism is provided.

The clutch member is a friction clutch.

The clutch member is rotated by a manual driving force from the manual focus operating member to generate a pinching member for pinching the driving mechanism, and generates a rotational moment for the pinching member to rotate. And a resistance member for adding a resistance force as a reaction of the manual driving force.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the lens barrel of the present invention, and FIG.
FIG. 2 is a side longitudinal sectional view showing the vicinity of the center, and FIG. 2B is a plan view of the friction clutch portion A according to the present invention shown in FIG. In FIG. 7A, illustration of a portion below the optical axis X of the lens is omitted. Also, the left and right sides of FIG.
That is, the front part and the rear part of the lens barrel are not shown.
However, the rear end portion B of the rear portion is illustrated as being drawn forward on the subject side. The lens barrel of the present invention is basically axially symmetric about the optical axis X.

1A, the first lens unit Gr1, the second lens unit Gr2, the third lens unit Gr3, and the fourth lens unit Gr4 with the optical axis X as a common axis in order from the left hand, that is, the front of the lens barrel. Are arranged. However, Gr1 and Gr4 are not shown. The first lens group Gr1 includes lenses G1, G
2 and G3, and the second lens group Gr2 is composed of lenses G4 and G4.
G5, and the third lens unit Gr3 includes lenses G6, G
7, G8, G9, and the fourth lens group Gr4 includes lenses G10, G11, G12, G13.

The lens G4 of the second lens group Gr2 is fitted and attached to the inner periphery of the substantially cylindrical ball frame 1 on the outer periphery. The ball frame 1 is screwed at the outer periphery thereof to the inner periphery of a long, substantially cylindrical fixed cylinder 10 with a screw portion a.
The lens G5 is attached to the rear surface of the lens G4 by bonding. At the rear end of the ball frame 1, a ring-shaped holding ring 3 is screwed to the inner periphery of the ball frame 1 at the outer periphery thereof with a screw portion b. At this time, by pressing the peripheral portion of the lens G5 forward by the pressing ring 3, the second lens group Gr2 is sandwiched and fixed between the lens frame 1 and the front and rear of the lens frame 1.

The lenses G6, G8,
The outer periphery of G9 is fitted and attached to the inner periphery of the substantially cylindrical ball frame 2 in which different diameters are combined. The outer periphery of the ball frame 2 is screwed to the inner periphery of the substantially cylindrical moving frame 5 with a screw c. Lens G7 is lens G6
It is attached to the back side by lamination. Lens G
8 and G9 are also bonded together. At the front end of the ball frame 2, a ring-shaped holding ring 4 is screwed around the outer circumference of the ball frame 2 to the inner circumference of the ball frame 2 with a screw portion d. At this time, the pressing ring 4 presses the peripheral portion of the lens G6 backward, so that the third lens unit Gr3
Is sandwiched and fixed between the ball frame 2 and the front and rear.

Further, at the rear end of the moving frame 5, a substantially cylindrical throttle inner cylinder 6 having a combination of different diameters is screwed to the inner periphery of the moving frame 5 at its outer periphery by a screw portion e. ing. At the rear end of the inner cylinder 6, a substantially cylindrical aperture holding cylinder 7 is fitted around the inner periphery of the inner cylinder 6 at the outer periphery thereof, and is fixed with screws f from the outside of the inner cylinder 6. I have. At this time, the ring-shaped diaphragm operation plate 8 is sandwiched and fixed between the diaphragm inner cylinder 6 and the diaphragm pressing cylinder 7 from front and rear. A ring-shaped fixed throttle portion 6a protrudes inward from the inner circumference of the throttle inner cylinder 6, and a throttle 9 is provided between this portion and the throttle operation plate 8. The aperture 9 is opened and closed by the operation of the aperture operation plate 8. The aperture holding cylinder 7 extends further rearward, but is omitted in the figure.

In the fixed cylinder 10, the second lens group Gr2
A pin 11 protrudes outward from the outer periphery in the vicinity. A roller 12 is provided rotatably around the axis of the pin 11. A long, substantially cylindrical rotary cam cylinder 13 is fitted on the outer periphery of the fixed cylinder 10, and a ring-shaped guide groove 13 provided on the inner peripheral surface thereof, which is axially symmetric about the optical axis X.
a, the roller 12 is rotatably slidably fitted to
The rotating cam barrel 13 is configured to be able to smoothly rotate around the fixed barrel 10.

In this embodiment, three sets of the combination of the pin 11 and the roller 12 are provided around the optical axis X at substantially equal angular intervals on the outer periphery of the fixed cylinder 10. Note that such a configuration is also provided at the front and rear portions of the fixed cylinder 10, but is omitted in the drawing. 13b is pin 1
1 and a relief hole for attaching the roller 12 to the fixed cylinder 10.

On the other hand, a pin 14 projects outward from the outer periphery of the moving frame 5. A roller 15 is provided rotatably around the axis of the pin 14. The roller 15 is rotatably slidably fitted in a cam groove (not shown) having a predetermined lead in the optical axis X direction provided on the inner peripheral surface of the rotary cam cylinder 13 around the optical axis X. Further, a roller 15 is rotatably and slidably fitted in a not-shown rectilinear guide hole formed in the wall surface of the fixed cylinder 10 in the optical axis X direction. At this time, when the rotating cam barrel 13 rotates around the fixed barrel 10, the roller 15 and the pin 14 are driven by the action of the cam groove, and move along the straight guide hole of the fixed barrel 10, thereby moving. Frame 5 and ball frame 2
, The third lens group Gr3 is driven in focus in the optical axis X direction to perform focusing.

In this embodiment, three sets of the combination of the pin 14 and the roller 15 are provided around the optical axis X at substantially equal angular intervals on the outer periphery of the moving frame 5. Incidentally, 13
c is an escape hole for attaching the pin 14 and the roller 15 to the moving frame 5. A configuration similar to the above-described configuration for driving the third lens group Gr3 for focus driving is employed as a configuration for driving the first lens group Gr1 for focus driving, but is omitted in the figure.

A short cylindrical float ring 16 is fitted on the outer peripheral surface of the rotary cam barrel 13. The guide pin 17 attached to the outer peripheral surface of the rotary cam barrel 13 passes through the elongated hole 16a formed therein.
The float ring 16 is slidable with respect to the rotary cam barrel 13 in the optical axis X direction within the range defined by the above. The float ring 16 is bent by a plate-shaped sandwiching lever 18 and a guide lever 19 so that each of the bent portions 18a,
At 18b and 19a, the contact is lighter than before and after. As shown in FIG. 3B, the bent portions 18a, 18b
Are provided at both ends in the circumferential direction of the float ring 16 at the front end of the sandwiching lever 18. The bent portion 19a is provided at the rear end of the guide lever 19.

In the vicinity of the center of the upper surface of the guide lever 19, the pinching lever 18 is moved near the front end thereof by the eccentric pin 2.
0 so as to be freely rotatable. Eccentric pin 20
Is attached to the upper surface of the guide lever 19 by caulking,
By rotating the friction clutch section A during assembly, the pinch lever 18 is moved back and forth by using the eccentricity. Thereby, the play of the sandwiching lever 18 and the guide lever 19 with respect to the float ring 16 is finely adjusted.

On the other hand, on the inner peripheral surface of the rear end of a substantially cylindrical torque ring 21 provided around the outer periphery of the rotary cam barrel 13, a guide lever 19 is attached at its front end with a screw g. At this time, the mounting hole 21a on the torque ring 21 side is a long hole whose position can be adjusted in the circumferential direction as shown in FIG. In the present embodiment, three sets of the above-described friction clutch parts A are provided around the optical axis X at substantially equal angular intervals.

In the torque ring 21, a boss 22 attached with a screw h projects outward from the outer periphery of the front end. A substantially cylindrical cover cylinder 23 is disposed on the outer periphery of the front end of the torque ring 21 so as to overlap the rear end thereof, and a ring-shaped guide groove 23a provided on the inner peripheral surface thereof and axially symmetric about the optical axis X. The torque ring 21 is rotatable around the rotary cam barrel 13 by slidably fitting the boss 22 to the boss 22. Reference numeral 23b denotes an escape hole for attaching the boss 22 to the torque ring 21.

A ring-shaped projection 21a protrudes outward from the outer peripheral surface of the torque ring 21, and a spring having a substantially ring shape and a wavy periphery is provided between the front surface and the rear end of the cover tube 23. 24 are sandwiched. Thereby, the torque ring 21 is urged rearward, and when the torque ring 21 rotates around the optical axis X, the cover cylinder 2
3, a friction torque is generated. This friction torque is
This prevents the torque ring 21 from idling unnecessarily and plays an important role in the function of the friction clutch portion A. Details will be described later. The cover tube 23 and the fixed tube 10 are
Each front end is connected and fixed to each other, but is not shown.

A substantially cylindrical fixing ring 2 is provided so as to extend between the torque ring 21 and the cover cylinder 23 from outside thereof.
5 is fitted, and is screwed and attached to the outer periphery of the rear end of the cover cylinder 23 with a screw portion i. The inner peripheral surface of the front end of the manual focus operation ring 26 is fitted to the outer peripheral surface of the rear end of the fixed ring 25. The manual focus operation ring 26 has a substantially cylindrical shape and is provided so as to cover the friction clutch portion A from the outside. A non-slip cover 27 made of a substantially cylindrical elastic member is fitted on the outer periphery of the manual focus operation ring 26.

On the inner periphery of the manual focus operation ring 26, there is provided a fitting portion 26a fitted to the rear end 18d of the sandwiching lever 18. A cylindrical elastic member j is fitted in a hole 18c near the center of the sandwiching lever 18, and the elastic member j is sandwiched between the manual focus operation ring 26 and the guide lever 19. The rattling of the eighteenth aspect is prevented, and a smooth operation is performed.

At the rear end B of the lens barrel of the present embodiment, a coupler 29 is provided on a mount 28, which is a portion for attaching the lens barrel to the camera body. During the autofocus operation, a rotational driving force from the camera body is transmitted to the coupler 29 and transmitted to the inner peripheral surface of the rotary cam barrel 13 via a transmission mechanism (not shown) in the lens barrel. Then, as the rotary cam barrel 13 rotates around the optical axis X, as described above, the first lens group Gr
The first and third lens groups Gr3 are driven in the optical axis X direction.
At this time, the float ring 16 provided on the outer peripheral surface of the rotary cam cylinder 13 only slides lightly with respect to the sandwiching lever 18 and the guide lever 19, and the friction clutch A
Is not affected. That is, the manual focus operation ring 26 does not rotate during the auto focus operation.

FIG. 2 shows the rear end surface of the lens barrel.
become that way. As shown in FIG.
The coupler 29 is in a state where the coupler 29 is looking into one of the upper peripheral portions. On the other hand, FIG. 3 shows the front of the camera body. As shown in the figure, the coupler 30 is in a state of being viewed at one location on the mount 31 on the camera body C side. At this time, when the mount 28 is attached to the mount 31 and the lens barrel is attached to the camera body C, the coupler 29 and the coupler 30 are automatically connected.

Here, the rotational driving force from the AF motor 32 built in the camera body is transmitted to a driving system (gear train) 33.
Through the coupler 30 and transmitted to the lens barrel via the coupler 29. The rest is as described above. Reference numeral 34 denotes an AF / MF switching button, which functions to switch between an auto focus operation and a manual focus operation each time the button is pressed. Reference numeral 35 denotes a lens attaching / detaching button for attaching / detaching the lens barrel to / from the camera body.

Returning to FIG. 1, at the time of manual focus operation, the manual focus operation ring 26 is manually rotated around the optical axis X. At this time, the fitting portion 26
The rear end 18d of the sandwiching lever 18 is driven in either the forward or reverse circumferential direction by a. On the other hand, since a friction torque is generated between the torque ring 21 and the cover cylinder 23, the guide lever 19 attached to the cover ring 23 is initially left, and at this time, the pinch lever 18 is pinched around the eccentric pin 20. Rotate. And the pinching lever 18
The float ring 16 is sandwiched between the bent portion 18a or 18b of the guide lever 19 and the bent portion 19a of the guide lever 19 more strongly.

Then, in response to the rotation of the manual focus operation ring 26, the torque ring 21 overcomes the friction torque and rotates in the same direction, and the rotation operation of the manual focus operation ring 26 is further performed via the float ring 16 by the rotating cam barrel. 13 is transmitted. As a result, the rotary cam barrel 13 rotates around the optical axis X, and the first lens unit Gr1 and the third lens unit Gr3 are driven in the optical axis X direction. FIG. 4 is a plan view showing the state of the friction clutch unit A at this time.
It is.

In FIG. 2, when the manual focus operation ring 26 is manually rotated in the circumferential direction shown by the arrow D, the rear end 1 of the pinching lever 18 is held by the fitting portion 26a.
8d is driven in the same direction. On the other hand, since a friction torque is generated in the torque ring 21, the guide lever 19 attached thereto is initially left behind, and at this time, the pinching lever 18 is rotated around the eccentric pin 20 counterclockwise in the figure. I do.

The bending portion 18 of the pinching lever 18
b and the bent portion 19a of the guide lever 19, the float ring 16 is sandwiched more strongly than before and after. Then
In response to the rotation of the manual focus operation ring 26 shown by the arrow D, the torque ring 21 overcomes the friction torque and rotates in the same direction, and the rotation operation of the manual focus operation ring 26 is not shown here via the float ring 16. The power is transmitted to the rotating cam barrel 13.

FIG. 5 is a perspective view showing the structure of the friction clutch section A. The clutch function will now be described again.
When a moves manually in the direction indicated by arrow D, the rear end 18d of the sandwiching lever 18 is driven in the same direction. On the other hand, since the guide lever 19 is regulated by the friction torque, at this time, the guide lever 19 is initially left behind by the resistance force, and a reaction occurs, and the pinching lever 18 is rotated around the eccentric pin 20 counterclockwise by the rotational moment. Rotate.

The bending portion 18 of the pinching lever 18
The force indicated by the arrow P, which presses the float ring 16 by b, is generated, and the float ring 16 is more strongly sandwiched between the bent portion 19a of the guide lever 19 and the front and rear. Then, the fitting portion 26 of the manual focus operation ring 26
In response to the operation indicated by the arrow D in FIG. 3A, the guide lever 19 overcomes the regulation by the friction torque and operates in the same direction, and the operation of the fitting portion 26a is further performed via the float ring 16 by the rotating cam cylinder 13 is transmitted. The arrow X indicates the direction of the optical axis.

FIG. 6 is a schematic view showing another example of the friction clutch unit according to the lens barrel of the present invention. FIG. 2B is a side longitudinal sectional view, and FIG. 2A is a plan view showing a main part. In FIG. 2B, a substantially cylindrical rotary cam cylinder 41 is disposed around the optical axis X, and a ring portion 41a provided on the outer periphery of the front end portion of the rotary cam tube 41 is provided with a sandwiching piece 42 provided on the outside thereof. It is fitted from the front and back. Specifically, as shown in FIG.
a, 42b and 42c, 42d sandwich the ring portion 41a from the four corners at the front and rear.

As shown in FIG. 4B, a substantially cylindrical manual focus operation ring 43 is disposed further around the optical axis X, and a bearing 43a provided on the inner periphery of the front end thereof has A shaft portion 42e protruding from the upper surface of the sandwiching piece 42 is rotatably fitted. Here, it is also slidable to some extent in the front-rear direction. A torque ring 44 is provided around the optical axis X between the rotary cam barrel 41 and the manual focus operation ring 43.
A projection 42f projecting more backward is fitted.

Further, the front end of a substantially cylindrical fixed cylinder 46 provided around the optical axis X between the rotary cam cylinder 41 and the manual focus operation ring 43 and the torque ring 4
A substantially ring-shaped friction member 45 is sandwiched between the rear end 4 and the rear end. Thereby, when the torque ring 44 rotates around the optical axis X, a friction torque is generated between the torque ring 44 and the fixed cylinder 46. In FIG. 6B, the right side of the rotary cam cylinder 41 and the fixed cylinder 46 are not shown. Also, the optical axis X
The lower part is not shown. This optical axis X is actually located further below in the figure.

At the time of manual focus operation, the manual focus operation ring 43 is manually rotated around the optical axis X. At this time, the sandwiching piece 42 is driven in either the forward or reverse circumferential direction together with the bearing 43a. On the other hand, since a friction torque is generated between the torque ring 44 and the fixed cylinder 46, the torque ring 44 has
The projection 42f fitted to the fitting portion 44a is left at the beginning, and a reaction occurs.
, The pinching piece 42 is rotated by the rotational moment. Then, the bent portions 42a and 4
2d, or by the bent portions 42b and 42c,
The ring portion 41a of the rotary cam cylinder 41 is sandwiched more strongly than the front and rear.

Then, the rotation operation of the manual focus operation ring 43 is transmitted to the rotary cam barrel 41 via the sandwiching piece 42. Thereby, the rotary cam barrel 41 rotates around the optical axis X in the same direction as the manual focus operation ring 43, and a lens group (not shown) is driven in the optical axis X direction in the same manner as in FIG. Will be At this time, the torque ring 21 also overcomes the friction torque and rotates in the same direction.

At the time of the autofocus operation, the lens group (not shown) is similarly driven in the direction of the optical axis X by rotating the rotary cam barrel 41 around the optical axis X by a driving mechanism (not shown). At this time, the ring portion 4 of the rotary cam cylinder 41
1a only slides lightly with respect to the sandwiching piece 42, and is not affected by this. That is, the manual focus operation ring 43 does not rotate during the auto focus operation.

The driving mechanism described in the claims corresponds to the rotary cam barrels 13, 41, the pins 14, the rollers 15, the moving frame 5, and the like in the embodiment. Ring 2
6,43. The driving force transmission mechanism described in claim 1 corresponds to the coupler 29 and the transmission mechanism (not shown) in the embodiment. Further, the sandwiching member referred to in claim 3 is the sandwiching lever 18 in the embodiment,
The resistance member corresponds to the clamping rings 42 and the resistance members correspond to the torque rings 21 and 44.

[0043]

As described above, according to the present invention,
There is no need to switch between auto focus and manual focus on the lens barrel side, and the manual focus operation ring does not rotate during auto focus operation. A lens barrel with good operability that can be performed can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a lens barrel of the present invention.

FIG. 2 is a diagram showing a rear end surface of a lens barrel.

FIG. 3 is a view showing the front of the camera body.

FIG. 4 is a plan view illustrating a state during operation of the friction clutch unit.

FIG. 5 is a perspective view showing a configuration of a friction clutch unit.

FIG. 6 is a schematic view showing another example of the friction clutch unit.

[Explanation of symbols]

 1, frame frame 3, 4 holding ring 5 moving frame 6 inner squeezing cylinder 7 squeezing holding cylinder 8 squeezing operation plate 9 squeezing 10 fixed cylinder 11, 14 pins 12, 15 roller 13 rotating cam cylinder 16 float ring 17 guide pin 18 pinching Lever 19 Guide lever 20 Eccentric pin 21 Torque ring 22 Boss 23 Cover cylinder 24 Spring 25 Fixing ring 26 Manual focus operation ring 27 Non-slip cover 28, 31 Mount 29, 30 Coupler 32 AF motor 33 Drive system 34 AF / MF switching button 35 Lens attachment / detachment button 41 Rotating cam cylinder 42 Pinching piece 43 Manual focus operation ring 44 Torque ring 45 Friction member 46 Fixed cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H044 BA04 BD06 BD16 BD18 BF03 DA01 DB01 DB02 DD03 DD12 DD19

Claims (3)

[Claims] 1. A focusing optical system, a driving mechanism for driving the focusing optical system, a driving force transmitting mechanism for transmitting a driving force from a predetermined driving source to the driving mechanism during an autofocus operation, and a manual focus A manual focus operation member for manually applying a driving force to the drive mechanism during operation; and a clutch member for connecting the manual focus operation member and the drive mechanism only when the manual focus operation member is operated. Characteristic lens barrel. 2. The lens barrel according to claim 1, wherein the clutch member is a friction clutch. 3. The clutch member is rotated by a manual driving force from the manual focus operating member to generate a pinching member for pinching the driving mechanism, and generates a rotational moment for the pinching member to rotate. 3. The lens barrel according to claim 1, further comprising a resistance member that adds a resistance force as a reaction of the manual driving force.