JP2000089081A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable manual operation and motor-driven operation to be performed without executing switching operation, to eliminate difference between actual manipulated variable and the manipulated variable of an index, and to reduce the remodeling of a lens barrel main body. SOLUTION: For example, the outer circumference of a zoom ring 18 driving a zoom lens is provided with an external tooth 27 and a motor 40 is coupled to the tooth 27 through a rotation transmission mechanism consisting of a differential gear. The rotation transmission mechanism is constituted so that the rotation of the motor 40 is transmitted to a rotary barrel 29 through a first large gear 32 and a small gear 34 and transmitted to the zoom ring from the output gear 28 of the barrel 29 through the tooth 27 at a motor-driven operation time. On the other hand, the rotation of the ring 18 is not transmitted to the motor 40 and it is relieved as the rotation of a second large gear 33. Thus, the index K is moved together with the ring 18 and the remodeling of the lens barrel main body is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel, and more particularly, to a lens barrel and an electric drive unit capable of performing both manual and electric operations in a lens unit of a camera.

[0002]

2. Description of the Related Art Conventionally, a lens barrel used for a camera, a television camera or the like is provided with a focus lens for focusing and a zoom lens for zooming. In some cases, switching between manual and automatic (electrically driven) can be performed. For example, a focus mechanism is driven by switching between rotation of a focus ring and rotation of an electric motor by a clutch mechanism.

That is, a coupling (intermediate) ring for driving the focus lens is provided. During manual operation, the focus ring is slid in a predetermined direction to be clutch-coupled to the coupling ring, and at the same time, the clutch coupling on the motor side is performed. Cancel. On the other hand, when auto focus is set, the focus ring is slid in the opposite direction to release the clutch connection to the connection ring, and at the same time, the motor side is clutch-connected to the connection ring. In this manner, by performing the predetermined engagement and disengagement of the clutch mechanism by the sliding operation of the focus ring in the front-rear direction, the manual operation and the electric operation (autofocus operation) are switched, and the focusing by the focus lens is performed by both operations. Will be

However, such manual switching and automatic switching by the clutch mechanism require a switching operation (front-back sliding operation) using a focus ring, which makes it impossible to quickly adjust conditions such as focusing on a subject.
There is a case where a shutter chance is missed. Therefore, conventionally, as a lens barrel whose operation has been simplified, for example, Japanese Patent No. 2597707, Japanese Patent Application Laid-Open No. H10-153
No. 730, which transmits a manual or electric driving force to the lens side via a member for holding a rolling element.

FIG. 6 shows an example of switching between automatic and manual using the above-mentioned rolling element holding member (Japanese Patent Laid-Open No. Hei 10-15373).
0). In FIG. 6, a holding frame 3 for holding a focus lens 2 is disposed in a lens barrel 1 so as to be movable back and forth at a helicoid portion H. A manually operated focus ring 4 is rotatably provided on the outer periphery of the lens barrel 1. It is attached. On the other hand, a motor for autofocus is arranged above the lens barrel 1 and the like, and the gear 5 is connected to this motor.

Further, on the outer peripheral portion of the lens barrel 1, an electric ring 6 in which the gear 5 meshes with the external teeth 6A,
And an intermediate ring 7 disposed between the focus ring 4 and the focus ring 4. That is, a plurality of balls (rolling members) 8 are rotatably arranged inside the intermediate ring 7, and the balls 8
And the side surface of the holding member 9 on the focus ring 4 side. The intermediate ring 7 is coupled to the extension 10 extending from the holding frame 3 of the focus lens 2 by a key groove, and serves as a driving member of the focus lens 2. Then, a focus index F (numerical value) is attached to the surface of the intermediate ring 7, and an instruction line is attached to the focus ring 4 side.

According to such a configuration, when the focus ring 4 is rotated, the electric ring 6 and the motor play a role of a load, and the electric ring 6 is fixed, and the intermediate ring 7 is reduced by a half amount. When the gear 5 is rotated in the same direction and the motor 5 is rotated by the motor, the focus ring 4 serves as a load, the ring 4 is fixed, and the intermediate ring 7 rotates via the electric ring 6. As a result, the focus lens 2 is moved in the optical axis direction. Such an operation state can be determined by an index F attached to the outer peripheral surface of the intermediate ring 7.

[0008]

However, in the configuration of the lens barrel shown in FIG. 6, since the rotation is transmitted through the ball (rolling member) 8, the intermediate ring 7 having the index F as described above is used. Is half of the rotation of the focus ring 4, and there is a disadvantage that the actual operation amount and the movement amount on the index F are different. For this reason, the operation feeling is different from that of the related art, and it may be difficult to handle.

Further, in order to arrange the intermediate ring 7 having the ball 8 and the electric ring 6, it is necessary to largely remodel the lens barrel main body, which leads to an increase in cost, and further utilizes the rolling of the ball 8. Therefore, there has been a problem that the operation may be unstable due to intrusion of dust or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to enable manual and electric operation without switching operation, and to provide a difference between an actual operation amount and a movement amount on an index. With less modification on the lens barrel body side,
An object of the present invention is to provide a lens barrel that can ensure stable operation.

[0011]

In order to achieve the above object, a lens barrel according to the present invention comprises a lens barrel having a lens built therein so as to be movable in an optical axis direction, and a lens barrel rotatable around an outer peripheral portion of the lens barrel. An operation ring for freely moving the lens in the optical axis direction by hand, external teeth formed on the outer periphery of the operation ring, and a motor for electrically moving the lens in the optical axis direction. The rotational force of the motor is transmitted to the operating ring via the external teeth, and when the operating ring is manually rotated, the rotation is not transmitted to the motor side but escapes to another rotating portion. And a rotation transmission mechanism described above. According to a second aspect of the present invention, as the rotation transmitting mechanism, a first large gear (differential large gear) integrated with the input / output gear and a second large gear (difference gear) semi-fixed slidably by an urging means. A dynamic large gear), a plurality of small gears (differential small gears) arranged to rotate between the first and second large gears, and a rotating shaft of the small gears, and an input / output gear. And a differential gear (differential gear device) including:

[0012] According to the above configuration, at the time of electric power, the rotation of the motor is transmitted to the external teeth by the differential gear as a rotation transmitting mechanism, and the operating ring on which the external teeth are formed rotates. The lens is driven back and forth by the rotation of the operation ring. In other words, this differential gear has, for example, three small gears (bevel gears) sandwiched between opposed first and second large gears (bevel gears), and these three small gears are integrated with the main shaft. A motor is connected to an input gear fixed to the first large gear,
The second large gear is semi-fixed so as to be able to slip, and the external teeth mesh with an output gear provided on the main shaft.
Therefore, during electric operation, the second large gear semi-fixed by a spring acts as a load to rotate the main shaft, and the rotational force is transmitted from the output gear to the operation ring. Note that a lens driven by the operation ring includes a zoom lens or a focus lens.

On the other hand, when the operation ring is manually rotated, the rotation is transmitted to the differential gear. In this case, the motor side becomes a load, and the second large gear half-fixed by the spring slips and rotates. Here, the rotation of the operation ring to the motor side is escaped. At the same time, the rotation of the operation ring drives the lens in a predetermined direction. Thus, in the present invention, only providing external teeth on the lens barrel main body side,
In other configurations, the rotation transmission mechanism is disposed outside the lens barrel main body, so that modification of the lens barrel main body can be significantly reduced as compared with the related art.

[0014]

1 to 5 show the structure of a lens barrel according to an embodiment. FIG. 1 shows the structure of a motor and a differential gear shown in FIG.
Denotes a structure inside the lens barrel, and this example is applied to a zoom lens. As shown in FIG. 5, a front movable lens (magnifying lens) 16 and a rear movable lens (magnifying lens) 17 constituting a zoom lens are provided behind a front fixed lens 15 in a lens barrel (tube) 14. These lenses 16 and 17 are moved forward and backward by rotation of a zoom (operation) ring 18.

That is, as shown in FIG. 2, the zoom ring 18 is rotatably arranged on the outer periphery of the lens barrel 14, and a cam cylinder 20 is connected to the zoom ring 18 via a pin 19. You. As shown in FIG. 3, the cam cylinder 20 has a cam groove 21A and a cam groove 21B. One cam groove 21A has a pin 23 on the front movable lens 16 side, and the other cam groove 21B has a rear cam groove 21B. The pin 24 on the side movable lens 17 is engaged and arranged. In addition, these pins 2
A rectilinear groove (restriction groove) 25 for moving the lenses 3 and 24 in the front-rear direction is formed in the lens barrel 14. When the cam barrel 20 rotates via the pin 19 when the zoom ring 18 rotates, the rectilinear groove is formed. 25 whose rotation is restricted by 25,
24 is driven linearly by the rotating cam grooves 21A and 21B. As a result, the lenses 16 and 17 move back and forth to change the image magnification.

On the outer periphery of the zoom ring 18,
An external gear 27 is formed, and an output gear 28 of a differential gear (rotation transmission mechanism) meshes with the external gear 27. The zoom ring 18 is a manually operated ring and also functions as an electric ring. Become. A zoom index (numerical value) K is attached to the outer periphery of the zoom ring 18.

As shown in FIG. 1 (A), the differential gear of this embodiment includes a rotary cylinder (support cylinder) 29 for integrally holding the output gear 28 and a main shaft for rotatably supporting the rotary cylinder 29. (Fixed shaft) 30 and the rotary cylinder 29
The input gear 31 is a bevel gear rotatably provided on the outer periphery of the
And a first gear 32 having the
A second bevel gear (bevel gear) 33 (facing the gears) provided opposite to the first and second gears 3 and 3
3 so as to be rotatable between 2 and 33 [FIG.
(B)] are arranged (the number is arbitrary) and small gears 34A to 34C made of bevel gears fixed to the rotary cylinder 29.
It is composed of The position of the small gear 34 in FIG. 1A is shifted.

The second large gear 33 is connected to the main shaft 3.
A spring (stopper spring) 37 and a holding plate 38 for pressing the side surface of the large gear 33 on the outer periphery of the shaft 36 to make it semi-fixed are provided.
Is provided. That is, as shown in FIG. 4, the shaft 36 has a portion 36 other than the portion that supports the second large gear 33.
At G, the left and right sides are cut, and a pressing plate 38 having a fitting hole 38H is fitted into the cut portion 36G, and a spring pressure is applied to the second large gear 33 via the pressing plate 38. Then, the input gear 31 of the first large gear 32,
The gear 41 supported by the motor 40 meshes.

According to the above configuration, when the motor 40 is electrically driven, the rotation is transmitted from the gear 41 and the input gear 31 to the first large gear 32, and the rotation of the first large gear 32 causes three small gears. While the gears 34 (A, B, C) rotate, the second large gear 33 meshing with the small gears 34 (A, B, C) at this time is pressed by a pressing plate 38 to which the urging force of the spring 37 is applied. Since the rotation is suppressed, the second large gear 33
Becomes a load, and the rotary cylinder 29 rotates. That is, the rotating cylinder 29 (and the output gear 2) is rotated at half the rotation speed of the first large gear 32.
8) rotates in the same direction (the number of rotations of the first large gear 32: the number of rotations of the output gear 28 = 2: 1).

The rotation of the rotary cylinder 29 is equivalent to the rotation of the output gear 28, and the external teeth 27 on the zoom ring 18 are rotated.
And the zoom ring 18 rotates. When the zoom ring 18 rotates, as described above,
, The cam cylinders 20 connected together rotate together.
The pins 23, 24 are moved along the rectilinear grooves 25 by the cam grooves 21A, 21B, and the movable lenses 16, 17 are moved back and forth, thereby performing a zoom operation.

On the other hand, when the zoom ring 18 is rotated at the time of manual operation, the motor 40 (gear 41) becomes a load, and the rotation given from the external teeth 27 to the rotary cylinder 29 via the output gear 28 is changed to a small gear. From 34 (A, B, C), the second large gear 3
3 is transmitted. That is, the first large gear 32 is the input gear 31
As a result, the second large gear 33 rotates at twice the rotational speed of the rotary cylinder 29 (output gear 28) against the urging force of the spring 37 (output). Number of rotations of gear 28: Number of rotations of second large gear 33 =
1: 2). Therefore, the second large gear 33 plays a role of releasing the rotational force (load) transmitted from the zoom ring 18 so as not to apply it to the motor 40.

In the above-described zoom operation, the index K is provided on the outer periphery of the zoom ring 18 and moves with respect to the fixed portion (pointing line) of the lens barrel 14, so that, as in the conventional example of FIG.
There is no difference between the actual operation amount and the movement amount of the index K, and the inconsistency in operation feeling as in this example is also eliminated.

In the above embodiment, the driving of the zoom lens has been described. However, the present invention can be similarly applied to the driving of a focus lens and the like. In the differential gear, the input gear 31 may be reversely disposed as an output gear and the output gear 28 may be reversely disposed as an input gear, or another configuration may be used.

[0024]

As described above, according to the present invention,
External teeth are formed on an operation ring for moving a zoom lens, a focus lens, and the like in the optical axis direction, and a rotational transmission mechanism including, for example, a differential gear is meshed with the external teeth, and a motor is transmitted through the rotational transmission mechanism. Is transmitted to the operation ring, and when the operation ring is manually rotated, the rotation is not transmitted to the motor but escapes to the rotating portion in the rotation transmission mechanism. Both manual operation and electric operation can be performed without switching operation by a clutch or the like, and there is no difference between the actual operation amount and the movement amount of the index. Moreover, it is possible to reduce the cost of the lens barrel main body by merely forming the external teeth on the operation ring, to reduce the cost, and to ensure a stable operation as compared with the case where the rolling element is used. There are advantages.

[Brief description of the drawings]

1A and 1B show the structure of a lens barrel according to an embodiment of the present invention, wherein FIG. 1A is a sectional view of a motor and a rotation transmitting mechanism, and FIG.

FIG. 2 is a cross-sectional view illustrating a drive mechanism of a zoom lens of the lens barrel according to the embodiment.

FIG. 3 is a diagram showing an arrangement configuration of a cam groove and a rectilinear groove of the lens driving mechanism of FIG. 2;

FIG. 4 is a diagram showing a configuration of a holding plate portion arranged on a side surface of a second large gear of FIG. 1;

FIG. 5 is a partial cross-sectional view showing the entire configuration of the lens barrel of the embodiment.

FIG. 6 is a diagram showing a configuration example of a conventional lens barrel.

[Explanation of symbols]

1,14 ... lens barrel, 4 ... focus ring, 8
… Ball (rolling element), 16, 17… Movable lens (for zoom), 7, 15… Nozzle, 18… Zoom ring (operation ring), 19, 23, 24… Pin, 20… Cam cylinder, 21A, 21B… Cam groove, 25 ... Straight running groove, 27 ... External teeth, 28 ...
Output gear, 29 ... rotating cylinder, 30 ... spindle, 3
1 ... input gear, 32 ... first large gear (bevel gear),
33 ... second large gear (bevel gear), 34 (A, B,
C) ... small gear (bevel gear), 37 ... spring, 38
... Holding plate, 40 ... Motor.

Claims (2)

[Claims] A lens barrel having a lens built therein so as to be movable in the optical axis direction; and an operation ring rotatably disposed on an outer peripheral portion of the lens barrel, for manually moving the lens in the optical axis direction. An external tooth formed on the outer periphery of the operation ring; a motor for electrically moving the lens in the optical axis direction; and transmitting a rotational force of the motor to the operation ring via the external tooth. A rotation transmission mechanism that, when the operation ring is manually rotated, does not transmit the rotation to the motor side but allows the rotation to escape to another rotating portion. 2. The rotation transmitting mechanism includes a first large gear integrated with an input / output gear, a second large gear semi-fixed to be slidable by an urging means, and a first and second large gear. A differential gear comprising: a plurality of small gears arranged so as to rotate between the plurality of small gears; and a main shaft having an input / output gear while fixing a rotating shaft of the small gears. Item 2. The lens barrel according to Item 1.