JP2575678Y2 - Lens barrel - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel used for a camera capable of automatic and manual focusing, and more particularly, to a lens barrel in which rotation of a manual ring and a rotary barrel is restricted.

[0002]

2. Description of the Related Art Conventionally, a camera capable of automatic and manual focusing has a mechanical switching mechanism such as a clutch for switching between automatic focusing (hereinafter, referred to as "AF") and manual focusing (hereinafter, referred to as "MF"). As described in Japanese Patent Application Laid-Open No. 58-208733, a method for performing the operation without rotating the motor in a direction in which a manual rotational force is applied to the focusing ring during MF is performed.
An electric signal of the same quality as that of the motor control during AF is generated in accordance with the rotation direction of the manual ring.

According to this method, the MF can be performed without difficulty, and since the operation of all the mechanisms in the AF and the MF is the same, the AF / MF can be switched regardless of the position of the focusing ring. .

[0004]

However, in the prior art, since the focusing operation is performed while rotating the motor even in the MF mode, the battery is consumed by the rotation of the motor during this time, and the life of the battery is shortened. A problem has arisen. In addition, there is a problem that when the battery runs out, neither MF nor AF can be performed.

The present invention has been made in view of the above-mentioned problems, and has been developed for AF / MF.
Can be switched without a mechanical switching mechanism, and when the rotation of the rotating ring for the manual ring and the AF is limited,
It is an object of the present invention to provide a lens barrel in which an unreasonable amount of force is not applied to each member and their engaging portions.

In order to solve the above-mentioned problem, a lens barrel according to the present invention is fixed to a camera body, and is held by the fixed barrel, and is rotated about an optical axis by a manual focusing operation. Excitation fixed to the manual ring and the fixed cylinder
And a stator that generates driving force
Automatic focusing drive means including a rotor that rotates by pressure contact,
Held in the fixed cylinder, the driving force from the automatic focusing drive means, a rotary cylinder which rotates about the optical axis, are connected by the engagement portion on the manual ring and the rotating cylinder, a focusing lens A holding cylinder for holding the group and moving the focusing lens group in the optical axis direction, and a driving force greater than the driving force of the automatic focusing driving means between the fixed cylinder and the manual ring; Frictional force applying means for applying a frictional force smaller than the stop maintaining force , and a cam provided between the manual ring and the rotary cylinder.
By the mechanism, the rotation of the manual ring or the rotating cylinder is
It is converted into the movement of the holding cylinder in the optical axis direction.
Using the manual ring as a source, stopping the automatic focusing drive means
Via a cam mechanism between the rotating cylinder stopped by holding force,
By moving the holding cylinder, the automatic focusing
With the cylinder as the original section, the cylinder is stopped by the frictional force of the frictional force applying means.
Via the cam mechanism between the holding cylinder and the manual ring.
A rotation-linear motion conversion unit to be moved, a groove provided on one side of the manual ring and the rotating cylinder, and a projection provided on the other side, between the manual ring and the rotating cylinder. And a rotation restricting unit that restricts a rotation range.

[0007]

According to the present invention, without the mechanical switching mechanism for switching between AF and MF, during AF, the manual ring is locked to the fixed ring by the frictional force applying means, and the rotation of the rotary cylinder is stopped. And focus is performed. At this time, the rotation restricting section causes the rotating cylinder to hit the manual ring, thereby restricting the rotation of the rotating cylinder.

Further, at the time of MF, the rotation of the rotating cylinder is prevented by the stop maintaining force of the automatic focusing driving means, and the rotation of the manual ring is transmitted to the holding cylinder to perform focusing. At this time, the rotation restricting portion causes the manual ring to hit the rotating ring, and the rotation of the manual ring is restricted.

As described above, since the rotation of the manual ring and the rotary cylinder is restricted, the rotation can be restricted at a predetermined position in both AF and MF. Further, it is possible to prevent an excessive force from being applied to the engaging portion between the holding cylinder, the manual ring, and the rotating cylinder.

[0010]

Next, with reference to the drawings and the like, an embodiment will be described.
This will be described in more detail. FIG. 1 is a sectional view including an optical axis of a first embodiment of the present invention. Hereinafter, the first embodiment will be described in the order of the optical system, the configuration, and the operation.

First, the optical system will be described. The fixed lens groups L1 and L3 are fixedly held by the fixed cylinder 1. The focusing lens unit L2 is held by the moving frame 8, and the moving frame 8
Is performed in the optical axis direction to perform a focusing operation.

Next, the configuration will be described. The fixed barrel 1 is a barrel for fixing a lens barrel to a camera body (not shown) via a lens mount 2. Lens mount 2
Denotes a mount portion on the lens side, which is fixed to the fixed cylinder 1,
This is a portion that engages with a camera body mount (not shown) on a camera body (not shown). The lens mount 2 is provided with a bearing hole 2a.

The coupling shaft 11 is engaged with a coupling (not shown) on the camera body side through the bearing hole 2a, and is rotated by a motor on the camera side. A gear 11a is provided at the end opposite to the lens mount 2 and meshes with the internal gear 4c of the rotary cylinder 4. The coupling shaft 11 is
It is pivotally supported on the gear side by the main plate 12.

The manually operated ring (hereinafter referred to as the MF ring) 3 is a fixed cylinder 1
Is rotatably fitted to. There is a gap between the MF ring 3 and the fixed cylinder 1 in the direction of the optical axis, and the wave washer 13 is inserted to provide an appropriate friction between the fixed cylinder 1 and the MF ring 3. The MF ring 3 is provided with an axial guide groove 3 a and a circumferential guide groove 3 b in a specific range in the circumferential direction of the MF ring 3. A rubber ring 9 is attached to the outer periphery of the MF ring 3 to cover the axial guide groove 3a and the circumferential guide groove 3b and improve the operability of the MF ring 3. A pattern (not shown) for the photoreflector 10 is provided at an end 3b of the MF ring 3 in the left optical axis direction in FIG. 1, and a pulse is generated by the photoreflector 10 when the MF ring 3 rotates.

The rotary cylinder 4 is rotatably fitted to the fixed cylinder 1 inside the MF ring 3. The rotary cylinder 4 is provided with a circumferential guide groove 4a, and a limiting projection 4b is provided corresponding to the circumferential guide groove 3b of the MF ring 3, and the rotary cylinder 4 is provided with a circumferential guide groove 3b. Can be relatively rotated only between the circumferential ends.

The intermediate cylinder 5 is fitted inside the rotary cylinder 4 so as to be rotatable with respect to the fixed cylinder 1 and movable in the axial direction. A circumferential guide groove 5a is provided on the inner periphery of the intermediate cylinder 5, and a pin 6 is implanted.

The pin 6 is implanted in the intermediate cylinder 5, penetrates the circumferential guide groove 4 a of the rotary cylinder 4, and fits in the axial guide groove 3 a of the MF ring 3. The moving frame 8 holds the focusing lens unit L2, is fitted so as to be movable in the optical axis direction on the inner periphery of the fixed barrel 1, and has a pin 7 implanted therein. The pin 7 penetrates the axial guide groove 1 a of the fixed cylinder 1 and fits into the circumferential groove 5 a of the intermediate cylinder 5.

The photoreflector 10 is fixed to the fixed cylinder 1 and generates a pulse when the MF ring 3 is manually rotated.
A signal is transmitted to the camera body via the electric circuit to stop the motor.

Next, the operation will be described. At the time of AF, the coupling shaft 11 is rotated by a rotational driving force from a motor provided on a camera body (not shown),
The rotary cylinder 4 rotates via the gear 11 and the gear 4c.

At this time, the frictional force caused by the urging force acting in the axial direction by the wave washer 13 between the MF ring 3 and the fixed cylinder 1 is applied to the circumferential guide groove 4 provided in the rotary cylinder 4.
The pin 6 implanted in the intermediate cylinder 5 by the action of
Is larger than the force for rotating the MF ring 3 via the axial guide groove 3a installed in the MF ring.

Therefore, when the MF ring 3 does not rotate and the rotary cylinder 4 rotates, the pin 6 moves in the optical axis direction along the axial guide groove 3a, and the intermediate cylinder 5 also moves. The moving frame 8 in which the pins 7 are implanted moves integrally in the optical axis direction by the circumferential guide groove 5a installed in the intermediate cylinder 5, and the focusing lens L
2 moves and focuses.

During MF, the MF ring 3 is manually rotated. At this time, the manual torque for rotating the MF ring 3 is M
The MF ring 3 rotates because it is large enough to rotate against the frictional force due to the urging of the pressure acting in the axial direction by the wave washer 13 between the F ring 3 and the fixed cylinder 1.

When the MF ring 3 rotates, a pulse is generated in the photo reflector 10, a signal is transmitted to the camera body via an electric circuit (not shown), and the motor stops. When the motor stops, a large torque is required to rotate the rotary cylinder 4. Since the speed from the motor on the camera body side to the rotary cylinder 4 is reduced at a considerable gear ratio and the efficiency is not very good, conversely, if the rotary cylinder 4 is rotated to rotate the motor, the increase is not efficient. Since the high-speed gear train is rotated, a large amount of torque is required. Therefore, at the time of MF where the motor is stopped, the rotary cylinder 4 can be regarded as being fixed.

When the MF ring 3 is further rotated, the pins 6 implanted in the intermediate cylinder 5 are brought into contact with the axial guide grooves 3 installed in the MF ring 3.
a, the circumferential guide groove 4 installed in the rotary cylinder 4
Move along a. Therefore, the intermediate cylinder 5 moves in the optical axis direction while rotating. Then, the moving frame 8 in which the pins 7 are implanted moves in the optical axis direction along the circumferential guide groove 5a provided in the intermediate cylinder 5, and the focusing lens L2 moves to focus.

Next, the relationship between the axial guide groove 3a, the circumferential guide groove 4a and the pin 6 will be described with reference to FIG. FIG. 2 is a development view as viewed from the direction A in FIG. 1, and the rubber ring 9 is omitted.

At the time of AF, the MF ring 3 is stopped. When the rotary cylinder 4 moves in the X direction in FIG. 2, the pin 6 is guided by the circumferential guide groove 4a and moves in the Y axis direction. Therefore, the intermediate cylinder 5 on which the pins 6 are implanted moves in the Y direction.

At the time of MF, the rotary cylinder 4 is stopped. M
When the F ring 3 moves in the X direction, the pin 6
a and is moved in the Z direction along the circumferential guide groove 4a. Accordingly, the intermediate cylinder 5 moves in the Z direction, that is, in the optical axis direction while rotating. When the intermediate cylinder 5 moves along the optical axis or while rotating, the pin 7 is moved by the action of the circumferential groove 5a.
The moving frame 8 moves by the same amount as the amount of movement of the intermediate cylinder 5 in the Y direction, and the focusing lens L2 moves to focus.

The focusing range is limited by bringing the limiting projections 4b into contact with both end surfaces of the circumferential guide groove 3b. That is, during AF, the MF ring 3 has the wave washer 1
3, the rotating cylinder 4 rotates, and the rotation range is limited by the rotation of the rotating cylinder 4 and the limiting projections 4b abutting on both circumferential end surfaces of the circumferential guiding groove 3b. Is done. Further, at the time of MF, the rotary cylinder 4 is practically fixed by the motor and the reduction gear of the camera body, and the MF ring 3 is rotated so that both circumferential end surfaces of the circumferential guide groove 3b abut on the limiting protrusion 4b. The range of rotation is limited.

It is assumed that the focus range is limited in another portion, for example, the case where the focus is limited between the pin 7 and the fixed barrel 1 during MF. Pin 7 is axial guide groove 1a of fixed cylinder 1.
, The movement of the intermediate cylinder 5 and the pin 6 is also limited. At this time,
In FIG. 2, the rotary cylinder 4 is in a fixed state,
Are also restricted from moving in the Y direction. When an external force is applied to the MF ring 3, the circumferential guide groove 4a attempts to further move the pin 6 in the Y direction, so that the pin 6 and the axial guide groove 3a,
Sticking occurs between the circumferential guides 4a. Also, the force in the Y direction applied to the pin 6 is applied to the pin 7 and the axial guide groove 1a.
Therefore, a force is applied to the threaded portion for attaching the pins 6 and 7, and the threaded portion may be broken.

In the first embodiment, the MF ring 3 is provided with the axial guide groove 3a, and the rotary cylinder 4 is provided with the circumferential guide groove 4a. However, as shown in FIG. The axial guide groove 41a may be provided in the groove 31a and the rotary cylinder 4.

In FIG. 3, at the time of AF, the MF ring 3 is stopped as described above. When the rotary cylinder 4 moves in the X direction, the pin 6 is guided by the circumferential end face of the axial guide groove 41a and moves in the Z direction along the circumferential guide groove 31a. Therefore, the intermediate cylinder 5 moves in the Z direction, that is, in the optical axis direction while rotating.

At the time of MF, the rotary cylinder 4 is stopped. MF
When the ring 3 is manually moved in the X direction, the pin 6 is guided by the axial end face of the circumferential guide groove 31a and is guided by the axial guide groove 41.
It moves in the Y direction along a. Therefore, the intermediate cylinder 5 moves in the Z direction.

FIG. 4 is a sectional view including an optical axis of a second embodiment of the present invention. Hereinafter, the configuration and operation will be described separately. The optical system is the same as in the first embodiment, and a description thereof will not be repeated. In addition, the configuration and operation are also the first.
The following description focuses on differences from the embodiment.

First, the configuration will be described. The difference from the first embodiment lies in the AF drive connection. In the first embodiment,
A motor and a coupling are provided on the camera body side, a coupling and a gear are provided on the lens side for engaging with the body side, and the driving force of the camera body side motor is transmitted to the rotary cylinder 4. In the example, as shown in FIG.
An ultrasonic motor 21 is installed in the lens barrel, and a stator 21a of the ultrasonic motor 21 is fixed to the fixed cylinder 1, while a rotor 21b is connected to the rotary cylinder 4 so that both can rotate integrally. I have. Other configurations are substantially the same as those of the first embodiment.

Next, the operation will be described. In the first embodiment, the motor is provided on the camera body side, and the rotation is transmitted to the rotary barrel 4 by the engagement of the body-side coupling and the lens-side coupling. However, in the second embodiment, the lens barrel is provided. The ultrasonic motor 21 is installed in the
The first stator 21a is fixed to a fixed cylinder, and the rotor 21b
And the rotary cylinder 4 are connected so as to rotate integrally. For this reason, if the rotation of the MF ring 3 is detected during the MF and the motor is stopped, the rotor 21b and the stator 21a of the ultrasonic motor are pressed with a considerable pressure, so that the rotor 21b and the rotary cylinder 4 are securely rattled. It is fixed to the fixed cylinder 1. Other operations are substantially the same as those of the first embodiment.

In the above embodiment, the circumferential guide groove for restricting rotation is provided on the MF ring, and the rotation restricting projection is provided on the rotary cylinder. Conversely, the MF ring is provided with a projection and the rotary cylinder is provided with a groove. Alternatively, a notch may be provided in the end face of the cylinder instead of the groove.

According to the embodiment of the present invention, the following effects can be obtained in addition to the reduction in battery consumption. That is, MF
Although the ring 3 and the rotary cylinder 4 are configured to rotate 360 °, the position of the focusing lens unit L2 is determined by the relative rotation position between the MF ring 3 and the rotary cylinder 4, and Since the rotation is restricted between the MF rings and the rotating cylinder, the focusing operation of the focusing lens unit L2 can be performed regardless of the rotational positions of the MF ring and the rotary cylinder.

Further, since the rotation between the MF ring 3 and the rotary cylinder 4 is restricted, even if a further force is applied after the restricting member abuts, the force is transmitted to the restricting portion and transmitted to the mating part. Is transmitted from the rotary cylinder 4 to the MF ring 3 at the time of AF, and to the MF ring 3 at the time of MF.
Since no force is transmitted to the pin 6 and the pin 7), the pin 6 and the pin 7 do not enter into the groove or the implanted portion such as the screw is destroyed, resulting in malfunction.

[0039]

As described in detail above, according to the present invention, a manual ring that rotates during MF and is fixed during AF,
The position of the focusing lens group is determined by the relative rotation position of the rotating barrel that rotates during AF and becomes fixed during MF, and the rotation of the focusing lens group is limited between the manual ring and the rotating barrel. Is going.

Therefore, switching between AF and MF can be performed without a mechanical switching mechanism, and MF can be easily performed without rotating the motor during MF.
-Low battery consumption compared to MF switchable cameras. Further, the position of the focusing lens group at the rotation restricted position does not change regardless of the rotational position of the manual ring and the rotary cylinder with respect to the fixed cylinder. Further, since the rotation is restricted between the manual ring and the rotary cylinder, no excessive force is applied to the members in the inside and the focusing lens group that engage with both.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a mechanical relationship between the MF ring and the rotary cylinder in the first embodiment of the present invention.

FIG. 3 is a diagram showing another mechanical relationship between the MF ring and the rotary cylinder applied to the present invention.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 L1 Fixed lens group L2 Focusing lens group L3 Fixed lens group 1 Fixed cylinder 2 Lens mount 3 MF ring 3a Axial guide groove 3b Rotation restriction groove 4 Rotation cylinder 4a Circumferential guide groove 4b Rotation restriction protrusion 5 Intermediate cylinder 6 Pin 7 Pin 8 moving frame

Claims (1)

(57) [Scope of request for utility model registration] 1. A fixed barrel mounted and fixed to a camera body, a manual ring held by the fixed barrel and rotated around an optical axis by a manual focusing operation, and a driving force fixed to the fixed barrel and excited by excitation Generate
The rotor that rotates by pressurizing
An automatic focusing drive means including, held in the fixed cylinder, the driving force from the automatic focusing drive means, a rotary cylinder which rotates about the optical axis, at the engaging portion in the manual ring and the rotating cylinder A holding cylinder, which is connected and holds the focusing lens group and moves the focusing lens group in the optical axis direction, between the fixed cylinder and the manual ring, a driving force of the automatic focusing driving means, A frictional force applying means for applying a frictional force which is large and smaller than a stop maintaining force of the automatic focusing drive means, and a cam mechanism provided between the manual ring and the rotary cylinder.
The rotation of the manual ring or the rotating cylinder is
To the movement in the direction of the optical axis.
With the ring as the original clause, stop by the stop maintaining force of the automatic focusing drive means.
The holding mechanism is provided via a cam mechanism between the rotating cylinder and the stationary cylinder.
Move the cylinder, and during autofocus driving,
The hand stopped by the frictional force of the frictional force applying means.
The holding cylinder is moved via a cam mechanism between the
Rotation between the manual ring and the rotary cylinder by a rotation-linear motion conversion unit, a groove provided on one of the manual ring and the rotary cylinder, and a projection provided on the other side. A lens barrel comprising: a rotation restricting unit that restricts a range.