JP2002131617A - Driving mechanism for lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving mechanism for a lens barrel which is advantageous to miniaturization because it does not newly require installation space for a moving amount detection means, and which can accurately detect the moving amount of a lens barrel while restraining manufacturing cost to the minimum. SOLUTION: This driving mechanism for the lens barrel drives the lens barrel by a motor, and a nearly columnar battery chamber and a cartridge chamber are arranged adjacently in a camera body so that their axial lines may be parallel, and a part of a revolving speed detection means for detecting the revolving speed of the output shaft of the motor corresponding to the driving amount of the lens barrel is arranged in nearly triangular prism-shaped space formed between the battery chamber and the cartridge chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel driving mechanism for extending a lens barrel to drive, for example, a zooming mechanism.

[0002]

2. Description of the Related Art Various types of lens barrel driving mechanisms for moving a lens barrel in a camera back and forth in order to perform, for example, an auto-focusing operation or a zooming operation have been proposed and developed. As a driving mechanism of such a lens barrel, for example, a driving mechanism having a motor, a driving gear fixed to an output shaft of the motor, and a reduction gear train for reducing the rotation speed of the driving gear is used. Are known.

Further, in the lens barrel driving mechanism having such a configuration, in order to perform focus adjustment and zooming adjustment as accurately as possible, when the lens barrel is moved, the amount of movement of the lens barrel is accurately controlled. It is important to: Therefore, in a lens barrel driving mechanism having such a configuration, for example, a pulse plate that is provided in parallel with a first gear or an intermediate gear in a gear train, and rotates integrally with the gear, 2. Description of the Related Art There is known a lens barrel provided with a moving amount detecting means for a lens barrel composed of a photo interrupter provided with a plate sandwiched from both sides.

However, the moving amount detecting means having such a configuration is usually installed in a limited space in a narrow camera body, so that assembling work is difficult. In particular, as described above, the pulse plate is arranged in parallel with each gear constituting the gear train, so that the installation area is necessarily limited. Therefore, in order to secure a wide installation area for the pulse plate or the like, it is necessary to take measures such as extending the lower part of the camera body to secure a space there, which is inconvenient for downsizing the camera body. In addition, in order to increase the number of rotations of the pulse plate and perform highly accurate movement amount detection, a small gear is required, so that the installation space is further increased and the cost is increased accordingly. .

[0005]

SUMMARY OF THE INVENTION Accordingly, in view of the above circumstances, the present invention does not require a new installation space for the moving amount detecting means, is convenient for miniaturization, and has high precision while minimizing manufacturing costs. It is an object of the present invention to provide a lens barrel drive mechanism capable of detecting the amount of movement of a lens barrel.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a lens barrel driving mechanism for driving a lens barrel by a motor, wherein a substantially cylindrical battery chamber and a patrone chamber are arranged in a camera body with their axes parallel to each other. A rotation number detecting means for detecting the rotation number of the output shaft of the motor corresponding to the driving amount of the lens barrel in a substantially triangular prism-shaped space formed between the battery chamber and the patrone chamber; Is arranged.

The motor is disposed with its axis parallel to the axes of the battery chamber and the patrone chamber. The worm fixed to the output shaft of the motor and the worm wheel meshing with the worm are used to reduce the rotational force from the worm wheel. It is preferable that the lens barrel is driven by a train of gears transmitted to the lens barrel.

It is preferable that the rotation speed detecting means includes a pulse plate fixed to the output shaft, and a photo interrupter for detecting rotation of the pulse plate.

It is preferable that the output shaft is provided between the worm and the pulse plate, and an oil scattering prevention flange for preventing lubricating oil applied to the output shaft and the worm from adhering to the photointerrupter is provided. .

Further, it is preferable that the camera body is provided with an oil scattering prevention wall which is located between the worm and the pulse plate and prevents the lubricant applied to the output shaft and the worm from adhering to the photointerrupter. .

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a camera body 9 provided with a lens barrel driving mechanism according to the present invention.
Is shown. The driving mechanism of the lens barrel includes a zoom motor 1, a worm 2 fixed to an output shaft 1A of the motor 1, and a pulse plate (rotation speed detecting means) 3 provided on a rotation shaft 2A of the worm 2. A photo interrupter (rotation speed detecting means) 4 provided on both sides of the pulse plate 3, a flange (oil scattering prevention flange) 5 provided on a rotation shaft 2 </ b> A between the pulse plate 3 and the worm 2, And a gear train 6. Reference numeral 7 denotes a lens barrel.

As shown in FIGS. 1 and 2, the motor 1 is located at the lower right of the camera body 9 (lower left as viewed from the front).
It is disposed vertically near the battery chamber 91 and the patrone chamber 92, and as shown in FIG. 2, a substantially triangular dead space is formed between the battery chamber 91, the patrone chamber 92, and the gear train 6. (Hereinafter, referred to as a triangular space T).

The worm 2 reduces the speed of the high-speed rotation of the motor 1 on the output shaft 1A side and transmits the reduced speed to the gear train 6, and is installed directly below the motor 1 in a vertically installed state. The output shaft 1A of the motor 1 (which constitutes the rotation shaft 2A of the worm 2) is press-fitted into a shaft hole 23 provided in the center of the worm 2 from the base end surface 21 to the front end surface 22 so as to be integrated. , And is rotationally driven by the motor 1 in a cantilever state. In addition, this warm 2
Is configured to orthogonally convert a vertical rotation operation into a horizontal rotation operation orthogonal to the vertical rotation operation in the camera body 9, whereby a rotational force is transmitted to a gear train in which a rotation shaft is arranged in a horizontal direction. You. When power is transmitted from the worm 2 to the gear train 6, a camera body 9 (9A) described later is used to prevent the worm 2 from coming off from the tip of the output shaft 1A due to a reaction from the gear train 6 side. On the side, a pressing plate 81 is provided so as to approach and face the tip of the output shaft 1A. That is, the holding plate 81 prevents the worm 2 from coming off from the output shaft 1A.

The pulse plate 3 constitutes a part of the rotational speed detecting means, and as shown in FIG. 3, is formed of a disk having a diameter R1 and is integrally fixed to the output shaft 1A. In this embodiment, three through holes (rotational speed detecting means) 31 are formed at intervals of 120 degrees. Since the pulse plate 3 is directly connected to the output shaft 1A of the motor 1 rotating at a high speed, the pulse plate 3 is increased in speed through a small gear or the like, unlike the conventional type in which the pulse plate 3 is installed on the side of the reduction gear train. Without this, highly accurate position detection can be performed.

The photo-interrupter 4 located in the triangular space T constitutes a rotation speed detecting means together with the pulse plate 3, and optically detects and counts the number of passages of the pulse plate 3 through the through holes 31. The number of rotations of the pulse plate 3 that rotates integrally with the output shaft 1A is detected, and the amount of movement of the lens barrel can be calculated.

The flange 5 is for preventing lubricating oil such as grease applied to the vicinity of the output shaft 1 of the motor 1 or the worm 2 from scattering and adhering to the photointerrupter 4, and has a diameter R2 (however R1> R2). And this flange 5 is the tip surface 2 of the worm 2
2 and the pulse plate 3, particularly on the rotation shaft 2 </ b> A closer to the worm 2 than the phytointerrupter 4.

The gear train 6 is configured to further reduce the rotational operation decelerated by the worm 2 and transmit the rotational operation to the lens barrel side in order to obtain a torque required for performing the extending operation of the lens barrel. The gear train 6 according to this embodiment includes a worm 2
And a plurality of gears including a worm wheel 61 that meshes with a gear train mounting portion 9A of the camera body 9. In particular, as shown in FIGS. 4 and 5, the camera body 9 is provided with a projection 9B projecting laterally from the gear train attachment 9A in such a state as to wrap around the worm 2 from below. A U-shaped rib (oil scattering prevention wall) 82 is formed as a wall.

The rib 82 and the flange 5
To prevent scattering of lubricating oil applied to
The camera body 9 is provided between the flange 5 and the pulse plate 3 so as to surround the lower half of the outer periphery of the output shaft 1A. In addition to this, for example, another rib having an appropriate shape such as an inverted convex shape or an inverted U shape may be further provided integrally with the pressing plate 81 (or separately from the pressing plate 81). That is, since the rib 82 surrounds the lower half of the outer peripheral surface of the output shaft 1A, another rib is provided so as to complement the upper half of the outer peripheral surface of the open output shaft 1A. Just do it. This allows the ribs to substantially completely shut off the worm 2 and the pulse plate 3 and the photointerrupter 4, thereby making it possible to more reliably avoid scattering of the lubricating oil.

Therefore, according to this embodiment, the photo interrupter 4, which is a part of the rotation speed detecting means, can be installed in the triangular space T, which is a dead space, without making the camera body 9 extra large. Become.

In addition, according to this embodiment, even if the output shaft 1A rotates at a high speed, lubricating oil such as grease applied to the output shaft 1A or the worm 2 scatters to various places, the rib 82 and the flange 5 prevents the lubricating oil from adhering to the photointerrupter 4. Therefore, since the number of the through holes 31 of the pulse plate 3 can be accurately counted by the photo interrupter 4, when detecting the movement amount of the lens barrel,
An error can be prevented from occurring, and the reliability increases.

[0021]

According to the present invention, since a part of the rotation speed detecting means is arranged in a substantially triangular prism-shaped space between the battery chamber and the patrone chamber in the camera body which has not been conventionally used, the rotation speed is reduced. There is no need to provide a separate installation space for the number detection means, and the size of the camera body can be reduced.

Further, according to the present invention, since the photo interrupter which is directly connected to the output shaft side of the motor capable of high-speed rotation and forms a part of the rotation speed detecting means is provided, the small gears and the like can be used as in the prior art. It is possible to accurately detect the amount of movement of the lens barrel without separately providing a speed increasing means such as intervening, and to drive a small and highly accurate lens barrel while suppressing an increase in manufacturing cost. A mechanism can be realized.

[Brief description of the drawings]

FIG. 1 is a front view showing the inside of a camera body provided with a lens barrel driving mechanism according to the present invention.

FIG. 2 is a bottom view of a main part showing a main part of the drive mechanism.

FIG. 3 is a schematic perspective view showing the driving mechanism.

FIG. 4 is an enlarged front view of a main part of the drive mechanism.

FIG. 5 is an enlarged bottom view of the driving mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 zoom motor 1A output shaft 2 worm 2A rotating shaft 3 pulse plate (revolution detecting means) 31 through hole (revolution detecting means) 4 photo interrupter (revolution detecting means) 5 flange (oil scattering prevention flange) 6 gear Row 61 Warm wheel 7 Lens barrel 81 Holding plate 82 U-shaped rib (oil scattering prevention wall) 9 Camera body 91 Battery room 92 Patrone room T Triangular space

Claims (5)

[Claims] 1. A lens barrel drive mechanism for driving a lens barrel by a motor, wherein a substantially cylindrical battery chamber and a patrone chamber are arranged adjacent to each other in a camera body with their axes parallel to each other. In a substantially triangular prism-shaped space formed between the battery chamber and the patrone chamber, a part of rotation number detecting means for detecting the rotation number of the output shaft of the motor corresponding to the driving amount of the lens barrel is provided. A driving mechanism for the lens barrel, which is disposed. 2. A driving mechanism for a lens barrel according to claim 1, wherein said motor is disposed with its axis parallel to the axes of said battery chamber and said patrone chamber, and is fixed to an output shaft of said motor. A lens barrel driving mechanism, wherein the lens barrel is driven by a worm and a gear train that transmits a rotational force from a worm wheel meshing with the worm to the lens barrel. 3. The driving mechanism for a lens barrel according to claim 1, wherein said rotation number detecting means includes a pulse plate fixed to said output shaft and a photo interrupter for detecting rotation of said pulse plate. A driving mechanism for the lens barrel, wherein the photo interrupter is provided in the substantially triangular prism-shaped space. 4. A driving mechanism for a lens barrel according to claim 3, wherein the lubricating oil applied to the output shaft and the worm adheres to the photo-interrupter by being positioned between the worm and the pulse plate on the output shaft. A driving mechanism for a lens barrel provided with an oil scattering prevention flange for preventing the occurrence of oil. 5. The drive mechanism for a lens barrel according to claim 4, wherein the lubricating oil applied to the output shaft and the worm adheres to the photointerrupter in the camera body, between the worm and the pulse plate. A lens barrel drive mechanism provided with an oil splash prevention wall for preventing oil scattering.