JP2721408B2 - Lens barrel - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel capable of performing an operation of extending an optical system by both automatic and manual operations.

[Prior art] Conventionally, a lens barrel attached to an autofocus camera is composed of a normal motor, etc. to handle low-contrast subjects where AF is difficult or to focus on the desired position of the subject. In addition to the automatic focus adjustment means
In some cases, a manual focus adjustment unit that enables manual operation is provided.

In a camera capable of mounting a lens barrel having two functions of such an automatic focus adjustment unit and a manual focus adjustment unit, it is necessary to select whether to perform automatic focus adjustment or manual focus adjustment at the time of shooting. Conventionally, the automatic focus adjustment means and the manual focus adjustment means of the lens barrel are selectively used by switching with a clutch mechanism, or a motor provided for automatic focus adjustment is provided by a switch provided on the camera or lens side. A power focus that is manually controlled is generally used.

Also, as a lens barrel that does not need to be switched by an automatic focus adjusting means and a manual focus adjusting means by a clutch or the like, an automatic focus adjusting system including a motor and the like and an optical system for rotating and feeding the manual focus adjusting system as an input system. A device using a roller bearing type differential mechanism connected to an output system has been proposed.

FIG. 8 is a sectional view of a lens barrel using a radial ball bearing as a differential mechanism.

In the figure, reference numeral 61 denotes a fixed cylinder including a mount connected to a camera body (not shown), and holds a fixed lens 69.
Reference numeral 68 denotes a moving lens barrel, and a moving lens 78 for focusing.
, And a male helicoid screw 68a provided on the outer periphery is screwed with a female helicoid screw 61a provided on the inner periphery of the fixed cylinder 61. The moving lens barrel 68 is provided with a vertical groove 68b parallel to the optical axis.

84 is a cored motor driven by a signal from a camera body (not shown), 83 is a spur gear attached to the output shaft of the motor 84, 82 is a spur gear that meshes with the spur gear 83, and 80 is a spur gear . The spur gear 82 and the spur gear 80 rotate integrally with a shaft 81 that penetrates a shaft hole formed in the fixed cylinder 61. Spur gear 80
Engages with a large gear 79c provided on a cylindrical inner race 79 of a ball bearing to transmit rotation. Reference numeral 66 denotes a ball bearing ball, 67 denotes a ball retainer, and a key 67a is formed on the retainer 67 to enter the vertical groove 68b of the movable lens barrel 68 to regulate the rotation of the movable lens barrel 68. . The retainer 67 has a plurality of comb teeth portions 67b formed on the outer peripheral portion thereof at equal pitches along which the balls 66 are rolled and closely fitted along the circumferential direction.

Reference numeral 76 denotes a manually operated ring forming an outer ring of the ball bearing, and a track surface 76a of the ball bearing is provided on the inner periphery. The manual operation ring 76 is provided with a vertical groove 76b parallel to the optical axis. A circumferential groove 76c is formed in the inner periphery of the manual operation ring 76, and fits into a ring-shaped projection 61b provided on the outer periphery of the fixed cylinder 61, and the light of the manual operation ring 76 is formed. The movement in the axial direction is regulated, and fixed position rotation is possible.
77 is a disk-shaped outer ring of a ball bearing, with a ball
A track surface 77a is provided in contact with 66, and the outer periphery is a manually operated ring 76.
Is fitted on the inner circumference.

65 is a disc spring, 64 is a holding plate, and a key portion 64a is provided on the outer periphery of the holding plate 64 so as to enter the vertical groove 76b of the manual operation ring 76. The holding plate 64 is pressed against the ball 66 by the disc spring 65. Further, the ball 66 is pressed against the raceway surface 76a of the manually operated ring 76. The ball bearing is pressurized by the disc spring 65, and at the same time, the pressing force also serves as a force for pinching the fixed cylinder 61 between the holding plate 64 and the manual operation ring 76. Accordingly, slippage of the ball bearing, which is frictional transmission, is prevented, and a rotation locking force of the manually operated ring 76 is generated.

The automatic focus adjustment and the manual focus adjustment in the lens barrel configured as described above are performed as follows.

The motor is activated by a signal from the camera during auto focus adjustment.
When the 84 is driven, power is transmitted to the inner race 79 of the ball race via the gears 83, 82, 80, 79c, and the inner race 79 rotates. At this time, since the rotation locking force is given to the manual operation ring 76 as one outer ring by the disc spring 65 as described above,
76 does not rotate, the ball 66 as a rolling element revolves while rotating (self-rotating), and the retainer 67 is also pressed by the ball 66 and rotates,
Moving lens barrel 68 keyed to key portion 67a of retainer 67
Also rotates, and the movable lens barrel 68 moves in the optical axis direction along the lead of the helicoid, so that the focus adjustment operation can be performed.

On the other hand, at the time of manual focus adjustment, the manual operation ring 76 is rotated. In this case, the inner race 79 of the ball bearing is
The motor 84 is connected to the motor 84 via the spur gear 83, and the rotation of the motor 84 is suppressed by the cogging force, so that the motor 66 does not rotate, so the ball 66 revolves while rotating, and at the same time, the retainer 67 and the moving lens system Can also be rotated to perform focus adjustment.

This lens barrel uses a differential mechanism as a mechanism for transmitting the rotational force associated with manual and automatic operations to the moving lens system, so the balance between the torques of each part is important and at least the following conditions must be met. Must be met.

T ₁ : Lens moving load torque T ₂ : Torque that can be transmitted from the inner and outer races of the ball race to cage 67 T ₃ : Rotation locking torque of manual operation ring 76 T ₄ : Rotation locking torque of inner race 79 η ₁ : Reduction ratio from outer ring 76, 77 to cage 67 (≒ 1/2) η ₂ : When reduction ratio from inner ring 79 to cage 67 (≒ 1/2), η ₁ T ₁ <T ₂ , η ₂ T ₁ <T ₂ η ₁ T ₁ <T ₃ , η ₂ T ₁ <T _{4 Further} , the reduction ratios η ₁ , η ₂ can be obtained as follows from FIG.

In FIG. 9, 87 is the ball, 86 is the trajectory of the contact point between the inner ring and the ball, and 85 is the trajectory of the contact point between the ball and the outer ring.
P ₁ and P ₂ indicate the diameter of the ball at the point where the ball contacts the outer ring and the inner ring, respectively, and S ₁ and S ₂ indicate the diameter at the point where the inner ring and the outer ring contact the ball. In FIG. 5, P ₁ = P ₂ .

FIG. 11 is a cross-sectional view showing a ball bearing portion forming the differential mechanism of FIG. 8 and showing the inner race 79 and the outer race of the ball bearing.
The raceway surfaces of 76 and 77 each form a 90 ° V-groove opposed to each other by inserting a ball as a rolling element. Arrow F ₃ in FIG. 11 shows the pressing force of the disc springs 65, the arrow F ₄
, The relationship between F ₄ under a pressure of the ball caused by the F ₃ is represented by the following equation.

The differential mechanism, since it is friction transfer mechanism, the force which can be transmitted is dependent on the pressure F _4.

FIG. 10 is a diagram showing the amount of change in the distance from the rotation axis of the ball when the contact angle between the ball as a rolling element and the raceway surface changes by a small amount. 87 is a ball as a rolling element, and 85 is a track. The plane 90 indicates the rotation axis of the rolling element 87. As can be seen from the figure, the smaller the angle (90−θa) formed between the rotation axis 90 and the raceway surface, that is, the direction of contact with the raceway surface farther from the rotation axis of the ball, such as 85a → 85, has the same radius r. With the same error
It can be seen that the change amount S of S ₂ and P ₁ when having Δθ becomes smaller as △ ₁ > △ ₂ .

[Problems to be Solved by the Invention] However, in a lens barrel using a conventional differential mechanism, the output from a motor for automatic focus adjustment and the manual focus adjustment means constantly move the lens barrel. Because it is connected to the differential mechanism, there is no problem with fine adjustment after AF, which is the normal use condition, but especially for beginner users etc. There was a problem that the operation resulted in a blurred photograph.

[Means for Solving the Problems (and Action)] According to the present invention, in a lens barrel using a differential mechanism and capable of performing automatic focus adjustment and manual focus adjustment without switching, a manual focus adjustment means is provided. Therefore, by providing the switching switch means for preventing the transmission of the force to the differential mechanism, the manual focus adjustment means is inadvertently moved at the time of shooting in an application where manual focus adjustment is completely unnecessary, and the out-of-focus photograph is taken. It is intended to prevent such a situation from being performed.

Specifically, the lens barrel according to the present invention includes a moving optical system configured to be movable along the optical axis direction and a moving optical system having an output unit connected to the moving optical system and having two input units. A moving mechanism, a manual operation member for moving the moving optical system by manual operation connected to one input portion of the differential mechanism, and an automatic operation connected to the other input side of the operation mechanism. A motor driving mechanism for moving a moving optical system, wherein the motor driving mechanism prevents transmission of force from the manual operation member to the differential mechanism, and enables transmission of force from the motor driving mechanism to the operating mechanism. A mode, an automatic / manual simultaneous mode in which force can be transmitted from the manual operation member to the differential mechanism, and a force can also be transmitted from the motor drive mechanism to the differential mechanism. Or Wherein it is from the manual operating member while not to transmit a force to the differential mechanism having a switching means for switching between manual mode to enable the transmission of force to the actuating mechanism.

Embodiment FIG. 1 is a cross-sectional view of an interchangeable lens barrel for an autofocus single-lens camera showing a first embodiment of the present invention.

1 is a mount for coupling to a camera body (not shown), 2 is a contact block for transmitting and receiving power, ground, electric signals, etc. to and from the camera body, 3 is a decorative ring coupled to the mount 1, and 4 is a screw on the mount 1. First joined at 5
The fixed barrel 6 is a third lens barrel connected to the first fixed barrel 4 with a screw 7, the second lens barrel 8 is connected to the third lens barrel 6 with a screw 9, and the 10 This is a second fixed barrel fixed to the two-lens barrel 8 with screws 11. Second fixed cylinder 10
A male helicoid screw 10a is provided on the outer circumference of
Female helicoid screw provided on the inner periphery of the first lens barrel 12
It is screwed with 12a. On the inner periphery of the first lens barrel 12, a first lens 13, which is a movable lens for performing focus adjustment, is held. The second lens barrel 8 holds a second lens 14 as a fixed lens. In the third lens barrel 6,
A third lens 15 which is a fixed lens is held, and an electromagnetically driven aperture unit 16 which is operated under the control of the camera is fixed by screws 17. Second fixed cylinder 10
, A cover cylinder 18 is fixed by screws 19. Second
A motor cover cylinder 20 is fixed to the lens barrel 8 with screws (not shown).

Reference numeral 21 denotes a manual operation ring to which a stopper ring 22 is integrally fixed with screws 23, and the stopper ring 22 is provided with a plurality of stopper grooves 22a parallel to the optical axis. The movement of the manual operation ring 21 in the optical axis direction is restricted by the second fixed cylinder 10 and the motor cover cylinder 20, and only the rotation around the optical axis is possible. On the inner periphery of the manual operation ring 21, a differential mechanism having a configuration described later is held.

An encoder unit 24 having a ball bearing therein is integrally fixed to the second fixed cylinder 10 with a screw 25. The second fixed cylinder 10 is provided with a notch 10b in the circumferential direction parallel to the optical axis, and a key 26 that passes through the notch 10b and is fixed to the encoder unit 24 with a screw is provided. Keyway 12b provided in one lens barrel 12 parallel to the optical axis
Mated. In this configuration, when the outer race of the ball race of the encoder unit 24 rotates, the key 26 also rotates integrally,
Since the first lens barrel 12 coupled to the key 26 and the key also moves linearly while rotating, the first lens 13 also moves, and focus adjustment can be performed.

Next, the configuration of the differential mechanism, which is a main part of the present embodiment, will be described.

28 is an inner ring of a rolling bearing, 30 is a ball as a rolling element,
29 is a retainer for taking out the rotation of the differential between the inner ring and the outer ring of the bearing.The retainer 29 is provided with a plurality of comb-shaped grooves 29a in the circumferential direction for holding the ball 30 without looseness. And a key 29b for transmitting rotation by being coupled to a key groove 24a provided on the outer shaft of the ball race of the encoder. Reference numeral 31 denotes a first outer ring of the bearing, which is fitted to the inner periphery of the manually operated ring 21. 32 is the second outer ring of the bearing, 33 is the second outer ring
Stopper pin 33
Is a groove 31a provided in the inner periphery of the first outer ring 31 in parallel with the optical axis.
As a result, the relative rotation of the first outer ring 31 and the second outer ring 32 is restricted. The first outer ring 31 has a screw 31c which is screwed into an inner periphery thereof with a screw 35a provided on the outer periphery of the first pressure ring 35.
Is provided. Numeral 34 denotes a coned disc spring for applying a pressure to the bearing in order to ensure the transmission of the differential mechanism by the rolling bearing.

Numeral 36 denotes a rotation-stop washer, which prevents a part of the bent portion 36a from entering the notch 31d provided in the first outer ring 31, and prevents the pressure ring 35 from rotating and changing the pressing force. Reference numerals 37 and 38 denote slip sheets, and 39 denotes a rotation preventing washer. A partially bent portion 39a enters a groove 21a provided on the inner periphery of the manual operation ring 21. 40 is a disc spring, 41 is a screw 41a on the outer circumference
, And is screwed with a screw 21b provided on the inner periphery of the manual operation ring 21 to set the pressing force of the disc spring 40 to a predetermined value.

The following relationship is established between the raceway surfaces 28a, 28b, 31b, and 32a that come into contact with the ball 30 that is the rolling element of the inner race 28 of the bearing, the first outer race 31, and the second outer race 32.

Inner ring side raceway surfaces 28a, 28b and outer ring side raceway surfaces 31b, 32a
The angle of each V-groove formed by (1) exceeds 90 °, and the raceway surface forming each V-groove is less than 0 ° with respect to the rotation axis of the ball.
Further, the angles formed by the raceways 28a and 28b on the inner ring side with the optical axis are equal, and the angles formed by the raceways 31b and 32a of the first and second outer races with the optical axis are also set to be equal. The contact angle is more than 0 ° and less than 45 °.

Reference numeral 42 denotes a large bevel gear, which is integrally fixed to the inner ring 28 of the bearing with a screw 43. 44 is a small bevel gear meshing with the large bevel gear.

45 is a gear unit including at least one worm gear in the gear train, and 46 is a motor driven by a signal from the camera body.

FIG. 2 is a perspective view of the gear unit 45 of FIG. 1, and corresponding parts are denoted by the same reference numerals. In Fig. 2, 47 is a worm gear directly connected to the motor shaft, and 48 is a worm gear
Worm wheel that meshes with 47.

In this embodiment, the gear unit including the worm gear is composed of a worm gear 47 and a worm wheel 48.

The advance angle of the worm gear is usually set to 4 ° or less due to self-locking, but is not limited to 4 ° or less when there is a margin in torque balance of the differential mechanism.

FIG. 3 is an enlarged sectional view of a radial type ball bearing which is a differential mechanism portion of FIG. 1, and corresponding portions are denoted by the same reference numerals.

In Figure 3, F ₁ represents the pressure applied by the disc springs. As shown in FIG.
The orbital surfaces of the outer races 31 and 32 form an obtuse V-shaped groove facing each other by inserting a ball as a rolling element, and the contact angle is greater than 0 ° and less than 45 °.

Next, setting of the torque balance in this configuration will be described.

According to this configuration, the inner ring 28 on the automatic focus adjustment side automatically shuts off the force from the differential mechanism side, that is, the manual operation ring 21 by the worm gear. It is not necessary to consider the rotation suppressing force on the focus adjustment side.

In addition, the manual operation ring 21 is used for manual focus adjustment.
Grease is applied between 10c and 21c, and a rotation locking force is given to the yield value of the shear stress of the grease.

The torque balance according to this configuration is set as follows.

1/2 T ₅ <T ₆ <T ₇ <T ₈ T ₅ : Maximum lens moving load torque T ₆ : Rotation inhibiting torque of manual operation ring T ₇ : Friction torque T ₈ : From the inner and outer rings of the differential mechanism The maximum transmission torque of the friction torque T ₀ is set as a slip torque by which the manually operated ring 21 and the first outer ring 31 and the holding plate 36 on the outer ring side are integrally slipped by the disc spring 40. When the output side retainer 29 is locked by infinite butting against the one-lens barrel 12, excessive force is transmitted to the gear unit 45 and the ball bearing portion of the differential mechanism portion, and the device is damaged. This is provided to prevent

Further, since T ₆ that is smaller than T _7, T _8, at the time of manual operation it is necessary to make this sharp with time is desirable better not organoleptically T ₆ much larger, and infinitely abutment It is.

T ₆ is in the automatic focusing, the inner ring is transmitted from the motor
It must have the following relationship with the maximum torque T ₈ that turns 28:

T ₆ > T ₈ However, this condition is not provided in the present embodiment, but a switch for detecting infinity and the closest end of the lens is provided on the output side of the differential mechanism which is the ball bearing retainer 29. It is no longer necessary.

Next, the operation of the present embodiment will be described separately for automatic focus adjustment and manual focus adjustment.

At the time of automatic focus adjustment, when the motor 46 is rotated by a signal from the camera side, the worm gear 47, the worm wheel 48, the small bevel gear 44, and the large bevel gear 42 rotate, and when power is transmitted to the inner ring 28 and the inner ring 28 rotates. manual operation ring, the rotation by the rotation inhibiting torque T ₆ is suppressed, the outer ring
31 and 32 do not move, so that the ball 30 revolves while rotating, the holder 29 also rotates on the ball 30, the encoder unit 24 keyed to the holder 29 also rotates, and at the same time the key 26 also rotates. As a result, the driving force is transmitted to the first lens barrel 12,
Focus adjustment can be performed. At this time, the amount of movement of the first lens can be known from the output of the encoder unit 24.

At the time of manual focus adjustment, when the manual operation ring 21 is rotated,
Since the outer ring side of the ball bearing rotates and the inner ring side does not rotate because rotation is prevented by the worm gear in the gear unit 45, the inner ring does not rotate. Therefore, the ball 30, which is a rolling element, sandwiched between the inner ring and the outer ring, revolves while rotating, the holder 29 also rotates on the ball 30, and the first lens barrel is rotated in the same manner as during automatic focus adjustment. Power is transmitted to the camera and focus adjustment can be performed.

According to the present embodiment, the reduction ratio of the operating mechanism has a small fluctuation because θ forms an obtuse angle as shown in FIG. 3, and the pressing force on the ball is even when the same disc spring is used. It becomes larger than usual, and the maximum transmission force of friction transmission also increases.

In the embodiment shown in FIG. 1, the operation of the switch knob 88 slidably moving in the optical axis direction provided on the motor cover cylinder 20 further switches the operation mode to three modes of AF only mode, manual only mode, and AF manual simultaneous mode. Switching is possible, so that the user can arbitrarily select. The switch knob 88 is linked with the electric switch 89 to transmit the mode change to the camera. Also AF
When the switch 89 is set to the only mode, a signal is sent to the camera side, and at the same time, the rotation preventing key 88a formed integrally with the switch knob 88 enters the stopper groove 22a formed integrally with the manual operation ring 21. In addition, the rotation of the manual operation ring 21 is prevented, and it is possible to prevent a case where the manual operation ring 21 is inadvertently moved by a hand holding the lens during AF shooting and an out-of-focus photograph is taken.

Next, the mechanical mechanism, which is a main part of the present invention, will be described in detail with reference to FIGS.

FIGS. 4 to 7 show the above-mentioned mode switching mechanism by operating the switch knob 88. Corresponding portions in FIG. 1 are denoted by the same reference numerals.

In these figures, 88 is the above-mentioned switch knob, 89 is the above-mentioned electric switch, 91 is an interlocking lever, 92 is a holding pin formed integrally with the switch knob 88, 93 is a spring, and 95 is a rotation prevention key. It is the same as 88a. Reference numeral 20a denotes a guide groove provided on the inner diameter of the motor cover cylinder 20 so as to hold the rotation preventing key 95 in a fitted state in the optical axis direction (left-right direction in the drawing). This guide groove 20a allows the rotation prevention key 9
5 is held so as to be movable in the optical axis direction.

The anti-rotation key 95 has a holding pin hole 95a, and a retaining pin 92 that passes through the holding pin hole 95a is attached to the retaining ring 9a.
4 and held by the spring 93 in a state where the retaining ring 94 on the left side of the figure is turned away.

The interlocking lever 91 is formed integrally with the switch knob 88, transmits the movement of the switch knob 88 to the electric switch knob 89a of the electric switch 89, and switches the electric switch 89.

Further, reference numerals 22 and 22a denote stop rings 22a formed integrally with the manual operation ring 21 as described above.

4 to 7 are diagrams showing different modes of the lens, and FIG.
FIGS. 6 and 7 show the manual only mode, and FIGS. 6 and 7 show the AF only mode.

 Next, the operation of each mode will be described in order.

First, in the mode shown in FIG. 4 in which the AF and the manual can be simultaneously performed, the electric switch 89 transmits a signal indicating that the AF can be performed to a circuit (not shown), and performs the AF according to a command from the camera. be able to.

At this time, since the manual operation ring 21 can also be freely operated, both of the AF manuals can be performed without switching by the above-described differential mechanism.

FIG. 5 shows a manual only mode. When the switch knob 88 shown in FIG. 4 is slid to the right in the figure, the electric switch 89 is switched to this mode. In this mode, by switching the electric switch 89, it is transmitted to the circuit that the lens is in the manual mode, and only the manual focus adjustment is possible by turning off the automatic focus adjustment mechanism.

In this mode, the lens becomes a complete manual lens and can be used for applications where AF is unnecessary.

6 and 7 show only the AF mode. In FIG. 4, when the switch knob 88 is slid to the left in the figure, the electric switch is switched, and at the same time, the rotation preventing key 95 is moved. Enter the stopper groove 22a,
Regulate 1 rotation.

In order for the rotation prevention key 95 to enter the stopper groove 22a,
Since the phase of the stopper groove 22a and the rotation prevention key 95 must match, when the phase does not match, the state becomes as shown in FIG. 6. At this time, the manual operation ring 21 is rotated to match the phase. If they are aligned, the manual operation ring is locked as shown in FIG.

In this mode, the lens becomes a lens with only perfect AF, and when there is no need for delicate adjustments etc., there is no accidental rotation of the manual operation ring with the hand holding the lens, preventing erroneous operation A great effect can be obtained.

In addition, since the above-mentioned mechanical lock mechanism is interlocked with the electric switch, each mode can be easily switched only by switching one switch, and operability is also improved.

Another Embodiment Next, as a second embodiment, a case where the structure of the present invention is used for a lens barrel equipped with a vibration wave motor will be described.

FIG. 12 is a longitudinal sectional view of a main part of a lens barrel according to another embodiment, and FIG. 13 is a longitudinal sectional view of a driving force generating unit removably incorporated in the lens barrel of FIG. is there.

In FIGS. 12 and 13, reference numeral 101 denotes an outer cylinder of the lens barrel, which has click grooves 101b, 101c, and 101d described later. 103 is an outer cylinder portion 103a arranged in front of the outer cylinder 101
And the inner cylinder part 103b and the outer cylinder part 1 arranged inside the outer cylinder 101
A fixed cylinder 105 having a helicoid forming part 103c arranged inside 03, a lens holder 105 screwed into a helicoid 103d formed on the inner peripheral surface of the helicoid forming part 103c of the fixed cylinder 103, L is The lens 104 fixed to the lens holder 105 is fitted in a circumferential groove formed on the outer circumferential surface of the outer tube portion 103a of the fixed tube 103 and a circumferential groove formed on the outer circumferential surface of the outer tube 101. The manual operation ring is rotatable about a central axis Z of L (that is, an optical axis). The lens holder 105 has a groove 1 extending in the radial direction with respect to the optical axis Z.
A lens holder driving arm 122 having a portion parallel to the optical axis Z is inserted into the groove 105a so as to be relatively slidable only in the optical axis direction of the lens L.

A cylindrical driving force generating unit 125 shown in FIG. 13 is inserted into an annular space between the outer tube 101 and the inner tube portion 103b of the fixed tube 103, and serves as a frame or a base plate of the unit 125. The cylindrical body 102 has an outward flange 1 at its front end.
In 02a, it is fastened to the flange portion 103e of the fixed cylinder 103 by a screw 123, and is fastened to the inward flange 101a of the outer cylinder 101 by a screw 128 in an inward flange 102c at the rear end.

On the outer peripheral surface of the cylindrical body 102, as shown in FIG. 13,
All components of the vibration wave motor 126 and the vibration wave motor 1
Motor bearing and output member 127 that contacts rotor part 26
And a manual operation input ring 117 for inputting the rotational torque of the manual operation ring 104. The manual operation force input ring 117 is provided with a large number of stop grooves 117a to be described later.

The components of the vibration wave motor 126 and the structure of the motor bearing / output member 127 will be described below.

The vibration wave motor 126 has an annular vibration member 106 having a trapezoidal cross-sectional shape, an electrostrictive element 107 physically bonded to one end surface of the vibration member 106, and a pressure contact with the surface of the electrostriction element 107. An annular vibration absorber 110 made of felt or the like, an annular spacer 109 arranged in contact with one end surface of the vibration absorber 110, an annular disc spring 108 for pushing the spacer 109 toward the annular vibration member, Screw portion 102b formed on the outer peripheral surface of body 102
Annular nut 112 screwed to the nut 112 and the disc spring 10
An annular washer 111 interposed therebetween, a rotating cylinder 113 which is a part of a rotor of the vibration wave motor 126, a rotating cylinder 113
In order not to transmit the axial vibration to the rubber ring 114, the annular circumferential moving member 115, and the cylindrical body 102, the outer peripheral projection 116a is inserted into the groove 106a of the vibrating member 106. And other members such as a vibration member rotation stopping member 116.

The rotating cylinder 113, the rubber ring 114, and the circumferential moving member 115 are integrally formed as a rotor of the motor 126, and the rotating cylinder 113 is driven by circumferential traveling wave vibration generated in the vibration member 106.
And a rotor composed of a rubber ring 114 and a circumferential moving member 115 rotate about the optical axis Z.

The nut 112 is a member for adjusting the contact pressure between the vibration member 106 and the circumferential direction moving member 115 by adjusting the resilient force of the disc spring 108, and includes a roller 118 and a manual operation force input ring 117 described later. It is also a means for adjusting the contact pressure between the rotary cylinder 113 and the rotary cylinder 113.

A motor bearing and output member 127 arranged adjacent to the end surface of the rotating cylinder 113 (ie, rotor) of the vibration wave motor 126
As shown in FIG. 13 and FIG. 14, a ring 120 fitted around the outer peripheral surface of the cylindrical body 102 so as to be rotatable only, and an axis Z of the ring 120 (the axis of the vibration wave motor) are orthogonal to each other. A roller support shaft 119 fixed so as to protrude from the outer peripheral surface of the ring 120 at at least three places on the circumference of the ring 120 on the radial axis to be rotated, and rotatably fitted to the roller support shaft 119. And a hollow stepped roller 118.

The ring 120 also serves as an output member of a driving force generating unit 125, and an L-shaped lens holder driving arm 122 for rotating the lens holder 105 is fastened to an end surface of the ring 120 by a screw 124. Has become.

The roller 118 is provided between the outer circumferential surface of the rotating cylinder 113 and the ring 117.
And a head flange 118a that engages with the outer peripheral surface of the head. The roller 118 prevents the rotational cylinder 113 and the ring 117 from rattling in the radial direction when rotating by the head flange 118a.
And the end face of the ring 117. The mutual contact pressure between the roller 118 and the end face of the rotary cylinder 113 is determined by the annular disc spring 108 and the annular nut 112 which are components of the vibration wave motor 126.

The manual operation force input ring 117 is rotatably fitted to the cylindrical body 102, and the ring 117 contacts the outer peripheral surface of the roller 118 at one end surface (the right end surface in FIGS. 12 and 13), The other end surface is in contact with the friction washer 121. The outer peripheral edge of the ring 117 is engaged with a concave portion on the inner peripheral surface of the manual operation ring 104, and the ring 117 is configured to be rotated by the manual operation ring 104. The ring 117 can rotate only when a driving torque greater than the frictional resistance between the friction washer 121 and the ring 117 is transmitted from the manual operation ring 104, and does not rotate otherwise. Therefore, the ring 117 does not rotate unless the user of the lens barrel rotates the manual operation ring 104 with a rotational torque that overcomes the frictional resistance between the ring 117 and the friction washer 121.

Reference numeral 122 denotes a lens holder driving arm fixed to the ring 120 by a screw 124, and the driving arm 122 is provided through a hole formed in the peripheral surface of the cylindrical body 102 and an inner cylindrical portion 103b of the fixed cylinder 103. And into the inner cylindrical portion 103b through the hole and inserted into the groove 105a of the lens holder 105. In addition,
The hole penetrating the peripheral surface of the cylindrical body 102 and the hole penetrating the inner cylindrical portion 103b of the fixed cylinder 103 are groove-shaped holes extending along the circumferential direction.

Reference numeral 131 denotes a switch knob, which is fitted and held on the outer cylinder 101 so as to be slidable in the optical axis direction. A click spring 132 is fixed to the switch knob 131. The click spring 132 is used for the click grooves 101b, 101c,
By engaging with any of 101d, the switch knob 13
It has a structure to hold 1 by clicking. A stop plate 133 has a hole 133a formed so as to be slidable in the optical axis direction with respect to the switch knob 131.
133b regulates the slide in the forward direction of the lens. A spring elastic portion 132a of the click spring 132 is engaged with the end portion 133c of the hole, and the end portion 133b of the stopper 133 is brought into contact with the switch knob 131 by its elastic force, so that the click spring 132,
The stopper plate 133 and the switch knob 131 can be integrally operated.

Next, the operation of the lens barrel according to the present embodiment having the above-described structure will be described.

When the user of the lens barrel tries to drive the lens holder 105 by the force of the vibration wave motor 126, a focusing switch (not shown) is operated. Then, a voltage is applied to the electrostrictive element 107 by an operation of a control circuit (not shown),
As a result, a vibration that progresses in the circumferential direction is generated in the vibration member 106, and the vibration of the vibration member 106 causes the rotation cylinder 113 and the rubber ring.
The rotor composed of 114 and the circumferential moving member 115 is rotated about the optical axis Z. The rotation of the rotor causes the hollow roller 118 to receive a rotational torque from the rotary cylinder 113. At this time, since the manual operation ring 104 is not rotated, the ring 117 is not rotated.
While rotating around the roller support shaft 119,
The roller 120 rolls along the end surface of the ring 17, and the ring 120 is rotated about the optical axis Z via a roller support shaft 119. Therefore, the lens holder driving arm 122 is also rotated about the optical axis Z together with the ring 120, so that the lens holder
The 105 is rotated about the optical axis Z and moved in the axial direction to perform auto focusing.

On the other hand, when the lens barrel user attempts to drive the lens holder 105 with the power of the fingers without driving the lens holder 105 with the force of the vibration wave motor 126, the manual operation ring 104 is operated without operating the focusing switch. The user rotates around Z with his finger. Then, the ring 117 is rotated about the optical axis Z by overcoming the frictional resistance with the friction washer 121. At this time, since the vibration wave motor 126 is not driven, the rotating cylinder 113 which is the rotor of the motor is not driven.
Is stationary, so the roller 118 is
And rolls along the end face of the rotary cylinder 113 while being rotated. As a result, the ring 1 is
20 is rotated about the optical axis Z, and the lens holder 105
Is axially moved while being rotated by the drive arm 122, so that manual focusing is performed.

Next, the operation of the mechanical mechanism, which is a main part of the present invention, will be described in detail.

FIGS. 15 to 18 are views showing different modes in the mode switching mechanism by operating the switch knob 131, and FIG. 15 is an AF manual simultaneous enabling mode, FIG.
The figure shows the manual only mode, and FIGS. 17 and 18 show the AF only mode.

First, in the simultaneous mode of AF and manual shown in FIG. 15, the mechanical lock mechanisms 131 to 133 are not mechanically connected to the driving force generating unit 125 of the vibration wave motor, but are not shown. Since the electric switch is switched to transmit an AF enable signal to a circuit (not shown), AF can be performed by a command from the camera. At this time, the manual operation ring 104 can also be freely operated, so that both the AF and the manual can be performed without switching.

In FIG. 16, when the switch 131 of FIG. 15 is slid rightward in the manual only mode, an electric switch (not shown) is switched to enter this mode. The manual mode is transmitted to the circuit by switching an electric switch (not shown) to the manual mode, and only manual adjustment can be performed by turning off the AF mechanism. Note that the mechanical lock mechanisms 131 to 133 are not mechanically connected to the driving force generating unit 125 similarly to the AF manual simultaneous mode in FIG. In this state, the lens becomes a complete manual lens, and can be used for applications where AF is unnecessary.

FIGS. 17 and 18 show an AF-only mode, and when the switch 131 of FIG. 15 is slid to the left in the figure, an electric switch (not shown) is switched to an AF-enabled state, and at the same time, a part of the mechanical lock mechanism is operated. The stop 133d of the stop plate 133 enters the stop groove 117a of the manual operation force input ring 117 to restrict the rotation of the manual operation ring 104 (the state in FIG. 18). In order for the tip 133d of the stopper plate 133 to enter the stopper groove 117a, the phase of the stopper groove 117a and the tip 133d of the stopper plate 133 must be matched. As shown, the tip 133d of the stopper plate 133 is the manual operation force input ring 1
The spring elastic portion 132a of the click spring 132
Absorbs the difference in stroke of the stopper plate 133 due to its elasticity. In such a state, the manual operation ring 104 is rotated, and the phase of the stopper groove 117a of the manual operation force input ring 117 and the tip 133d of the stopper plate 133 are matched, whereby the elastic force of the spring elastic portion 132a of the click spring 132 is adjusted. The tip 133d enters the stopper groove 117a, and the
As shown in the figure, the rotation of the manual operation ring 104 is restricted.
In this mode, the lens becomes a lens with only perfect AF, and when there is no need for fine adjustment etc., it is possible to prevent accidental rotation of the manual operation ring with the hand holding the lens, which can prevent erroneous operation .

In each state of FIGS.
As a method of retaining the click grooves, the click portions of the click springs 132 are formed by the click grooves 101b, 101c,
The click is held by engaging with d.

[Effects of the Invention] As described above, in a lens barrel that uses a differential mechanism and can perform automatic focus adjustment and manual focus adjustment without switching, the force from the manual focus adjustment means to the differential mechanism Transmission (AF) to prevent transmission of
If only one mode (AF only mode) is newly added, that is, by adding one position (AF only mode) in addition to the two positions of AF manual simultaneous mode and manual only mode, manual focus adjustment can be performed. This eliminates the need for the user to inadvertently move the manual focus adjustment unit when taking a picture for completely unnecessary use, and has the effect of preventing the out-of-focus picture from being taken.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a lens barrel according to the present invention. FIG. 2 is a perspective view of a worm gear portion of FIG. FIG. 3 is a sectional view of a differential mechanism. FIG. 4 to FIG. 7 are cross-sectional views of essential parts showing respective switching positions of the mechanical lock mechanism according to the first embodiment of the present invention. FIG. 8 is a sectional view showing a conventional example. FIG. 9 is an explanatory diagram of a reduction ratio of a differential mechanism. FIG. 10 is a diagram showing a change in a contact radius due to a manufacturing error. FIG. 11 is a cross-sectional view of a conventional differential mechanism. FIG. 12 is a sectional view of a second embodiment of the lens barrel according to the present invention. FIG. 13 is a sectional view of a driving force generating unit according to the second embodiment. FIG. 14 is a front view of a motor bearing / output member 127 according to the second embodiment. FIG. 15 to FIG. 18 are cross-sectional views of main parts showing respective switching positions of the mechanical lock mechanism of the second embodiment. 20a Guide groove 22 Stopper ring 22a Stopper groove 88 Switch knob 89 Electric switch 89a Electric switch knob 91 Interlocking lever 92 Holding pin 93 Spring 94 Stop Wheel 95 Rotation prevention key 95a Holding pin hole 104 Manual operation ring 117 Manual input force input ring 117a Stopper groove 125 Drive force generating unit for vibration wave motor 131 Switch knob 132 … Click spring 133 …… stopper plate 133d …… the tip of the stopper plate

Claims (1)

(57) [Claims] 1. A moving optical system configured to be movable along an optical axis direction, a differential mechanism having an output section connected to the moving optical system side and having two input sections, and the differential mechanism. A manual operation member connected to one input unit for moving the moving optical system by manual operation, and an automatic operation unit connected to the other input side of the operating mechanism for moving the moving optical system. An auto mode in which a lens barrel having a motor drive mechanism prevents transmission of force from the manual operation member to the differential mechanism, while allowing transmission of force from the motor drive mechanism to the operation mechanism; An auto / manual simultaneous mode for enabling transmission of force from the operating mechanism to the differential mechanism, while also enabling transmission of force from the motor drive mechanism to the operating mechanism; A lens barrel and having a switching means for switching between manual mode to enable the transmission of force to the differential mechanism force from said manual operating member while not transmitting the differential mechanism from.