JPH0331930Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a lens barrel with a built-in motor.

[Prior art]

Many lens barrels are known that include a built-in motor for driving an aperture unit or a focus lens and a zoom lens.

Conventional motors built into lens barrels are pencil-type motors (solid motors) such as so-called iron core motors, coreless motors, or brushless motors.
There is a hollow type motor known from Utility Model Publication No. 51328 of 1982 and Japanese Patent Application Publication No. 147131 of 1982.

[Problems with conventional technology]

In the aforementioned conventional lens barrel with a built-in motor, in the case of the pencil-type motor, a protrusion is created on the exterior of the lens barrel to accommodate the motor, and the lens of the lens optical system is Special considerations have been made to the lens optical system, such as increasing the distance between lenses or reducing the light beam passage diameter, resulting in larger lens barrels and increased costs.

Furthermore, in the case of later solid type motors, the rotor unit and stator unit of the motor unit were disposed on the inner and outer peripheries of the lens barrel member constituting the lens barrel, resulting in a complicated lens barrel configuration.

[Problem to be solved by the invention]

The present invention has a motor for driving a focus lens or a variable magnification lens built into the lens barrel, and the motor can smoothly drive the lens without creating a protrusion on the exterior of the lens barrel. To provide a lens barrel suitable for incorporating a motor that avoids complication of structure.

[Means to solve]

This invention consists of a movable lens, a cylindrical fixed tube,
a cylindrical moving ring that is disposed at an inner diameter position of the fixed barrel and moves the movable lens in the optical axis direction as the movable lens moves in the optical axis direction; and a cylindrical moving ring that is disposed between the fixed barrel and the movable ring. a bearing in which a rotating ring that receives a bearing ball and rotates is provided at an outer diameter position of the movable ring, and a radial space between the fixed cylinder and the movable ring formed by the bearing; a driving force generating mechanism including a disposed motor, the rotary ring constituting a part of the bearing is rotated by the output of the driving force generating mechanism, and the inner diameter surface of the rotary ring and the movable ring are rotated. A lens barrel with a built-in motor is featured in which the movable ring is moved in the optical axis direction by rotation of the rotary ring by a helicoid mechanism formed on the outer diameter surface.

(Example of the present invention) FIG. 1 shows a sectional view of the lens barrel of the embodiment.

In the figure, reference numeral 1 denotes a fixed tube, and a bayonet mount 1A connected to a camera (not shown) is attached to one end of the fixed tube on the camera side.

2 indicates the first moving ring, 4 indicates the second moving ring,
Focusing lenses L ₄ to L ₆ and L ₁ to _{L 3} are respectively held. The outer circumferential surface of the second movable ring 4 has a fitting portion 4a that fits into the inner diameter portion 2a of the first movable ring 2, and a fixing means for fixing the second movable ring 4 to the movable ring 2. The fixing means engages a plurality of protrusions 4b, 4b, .

Reference numeral 6 denotes a motor held in the fixed cylinder 1, which consists of yokes 6a ₁ and 6a ₂ fixed to the fixed cylinder 1, a stator made of permanent magnets (not shown), etc., and a rotor made of a coil, a rotating shaft 6b, etc. . _G1 ～
G _o indicates a group of gears constituting a gear mechanism that increases and decreases the number of rotations in conjunction with the rotating shaft 6, and these gears are pivotally supported by a base plate 8 fixed to the fixed cylinder 1.

Reference numeral 10 denotes a rotating ring that rotates at a fixed position of the fixed cylinder 1. The rotating ring 10 is provided with a helicoid portion 10a on its inner diameter that screws into the helicoid portion 2c formed on the outer periphery of the first movable ring 2, and further rotates. A V-shaped ball race groove 10b for receiving the bearing ball 12 is formed on the outer periphery of the ring 10.

The bearing balls 12 are arranged in the ball race groove 10b of the rotating ring 10 by a ball spacer 14 so as to be continuous with each other or at regular intervals by the spacer 14, and are fitted into the inner periphery of the fixed cylinder 1 and have an inclined surface at one end. a first ball receiving ring 16 provided;
It is held by a second ball receiving ring 18 that is screwed into the threaded portion 1a on the inner surface of the fixed cylinder 1.

20 is the first and second ball receiving rings 16, 18
This is a plate-shaped spacer whose free end is bent along the inclined surface of the first ball receiving ring 16, and adjusts the pressing force of the ball 12 by the bent portion 20a. 22 is a position detector such as an encoder disposed within the aforementioned gear mechanism.

A part of the outer periphery of the rotary ring 10 has a small diameter, and a gear ring 24 is fixed to the outer periphery of the small diameter part 10c, and the gear ring 24 is threadedly engaged with the output gears of the gears G ₁ to G _o .

In the above configuration, a space is formed between the movable ring 2 and the fixed cylinder 1 so that the motor 6 and the gear mechanisms G1 _to G _o can be accommodated, and this space is formed between the fixed cylinder and the movable ring 2. The bearing components 10, 16, 18 of the balls 12, 12, . . .

D is a diaphragm unit fixed to the inner peripheral surface of the movable ring 2 and the small diameter wall 2e, and EMD is a motor for driving the diaphragm unit D. The motor EMD is fixed to the inner peripheral surface of the movable ring 2.

(Operation of this lens barrel) This lens barrel is attached to a camera (not shown), and a motor drive circuit is activated to drive the motor 6 by a focusing control means provided on the camera side. motor 6
The rotational force passes through the gear mechanism G ₁ ~ _{G o} to the rotating ring 1
0, and the rotating ring 10 is rotated into position by bearing means. The rotation of the rotating ring 10 is transmitted to the movable ring 2 which is helicoid-coupled, and the key member 26 extending from the fixed cylinder 1 is engaged with the linear keyway 2d on the outer periphery of the movable ring 2. Therefore, the movable rings 2 and 4 move straight in a direction parallel to the optical axis O, and the lenses L ₁ to _{L 6} are moved.

In this embodiment, as described above, focusing lenses L ₁ to _{L 6} are used.
The movable rings 2 and 4 holding the movable rings 2 and 4 are movably held inside the fixed cylinder 1 by bearing means 10, 16, and 18, and the movable rings 2 and 4 are held between the movable ring and the fixed cylinder by the bearing means. , 4, and the gear mechanisms G 1 to _{G o} are formed to maintain the external cylindrical shape of the lens barrel structure, and the motor 6 in the gap where the gear mechanisms G ₁ to G o are not disposed. The structure can be simplified because the circuit parts that make up the motor drive circuit can be housed therein.

Furthermore, in the configuration of this embodiment, the entire lens barrel can be roughly divided into two units, and the assembly of the lens barrel can be streamlined. In other words, in the figure, the lens system and mechanical subsystem are separated into the first and second parts.
The movable rings 2 and 4 are assembled into one lens system unit, and the motor, gear mechanism, and bearing means are assembled into one mechanical system unit in the fixed cylinder 1, and the helicoid of the first movable ring 2 and the rotary ring 10 is rotated. Align the starting point and fit the tool rod shown by arrow A from the outside into the engagement hole (groove) 26a provided in the end surface in the direction parallel to the optical axis of the scale ring 26 fixed to the rotating ring 10, and move the tool rod A around the optical axis O. The rotating ring 10 is rotated by rotating the rotating ring 10.

By rotation of the rotary ring 10, the lens units 2, 4, _L1 to _L6 are fitted into the mechanical unit.

Reference numeral 28 denotes a cosmetic ring that is placed on the outside of the fixed cylinder, and the cosmetic ring 28 is placed on the lens system unit after it has been assembled into the mechanical system unit.

As described above, according to this embodiment, the lens system is mounted on the movable ring 2, the motor 6, the gears G ₁ to _{G o} , and the bearing means are mounted on the fixed barrel, and the lens barrel is divided into two units. This enabled us to streamline assembly.

[Effects of the invention] The present invention has a bearing between the fixed cylinder and the movable ring, and the motor is placed in the radial space formed by this bearing, thereby saving a dedicated motor space. It was possible to provide a cylindrical lens barrel with a built-in motor without increasing the size of the motor. In addition, the rotating ring that constitutes the bearing is used as a motor output transmission member,
Furthermore, the movable lens is moved by moving the movable ring in the optical axis direction using a helicoid mechanism formed on the inner diameter surface of the rotating ring and the outer diameter surface of the movable ring, which reduces the number of parts and makes it compact. We were able to provide a lens barrel with a built-in motor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. 1... Fixed tube, 2, 4... Moving ring, 6... Motor,
G ₁ ~ G _o ... Gear mechanism, 10... Rotating ring.

Claims (1)

[Claims for Utility Model Registration] A movable lens, a cylindrical fixed tube, and a cylinder that is disposed at an inner diameter position of the fixed tube and moves the movable lens in the optical axis direction as the movable lens moves in the optical axis direction. a moving ring disposed between the fixed cylinder and the moving ring, a bearing having a rotary ring provided at an outer diameter position of the moving ring, which rotates by receiving a bearing ball; and the bearing. a driving force generating mechanism including a motor disposed in a radial space between the fixed cylinder and the movable ring; The movable ring is rotated by the output of the generating mechanism, and the movable ring is moved in the optical axis direction by the rotation of the rotary ring by a helicoid mechanism formed on the inner diameter surface of the rotary ring and the outer diameter surface of the movable ring. A lens barrel with a built-in motor.