JP3080386B2 - Camera rotation drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotary driving device, more specifically, a planetary gear clutch using a planetary gear mechanism, which selectively switches at least two loads to transmit torque. The present invention relates to a rotary drive device that performs

[Prior Art] The rotational driving force of a drive source such as a motor that rotates reversibly is selectively switched and transmitted to at least two loads by a planetary gear clutch using a planetary gear mechanism (differential gear mechanism). Conventionally, various rotary drive devices have been provided.

For example, in an exposure / focus adjustment device for a camera disclosed in Japanese Patent Application Laid-Open No. 63-23138, an exposure control (AE) mechanism and a focus control (AF) mechanism are applied to a driving force from a motor via a planetary gear clutch. And selectively transmit the signals.

When this planetary gear mechanism (differential mechanism) is used as a clutch means, a driving force from a rotary drive source such as a reversible motor is transmitted to the sun gear S as shown in FIG. The rotation driving force is selectively switched and transmitted from the gear P to the carrier C side and the internal gear I side. The load on the carrier C side and the internal gear is set so that the magnitude of the load on the I side always increases on one side. That is, the side with the smaller load is normally driven, and the reaction force is held on the side with the larger load. To drive the side with the larger load, the side with the smaller load is locked so that the reaction force when the side with the larger load is driven is held.

In the exposure / focus adjustment device of the camera, when operating a focus control mechanism with a large load, a gear that drives the exposure control mechanism is locked by a cam, a lever, and a magnet.

Therefore, it can be considered that this clutch means is an electromagnetic clutch which can selectively switch the unidirectional rotation of the motor between two systems of loads.

Also, Japanese Patent Application Laid-Open No. 1-102439 discloses a rotary drive mechanism using a differential gear mechanism as a planetary gear clutch. This mechanism is a further development of the mechanism disclosed in JP-A-63-23138, in which a mechanism having a shape capable of locking rotation in both directions is provided on a mechanism for locking the side with a small load, and the side with a small load is provided. Is an electromagnetic clutch which is rotatable in one direction and rotatable in both directions on the side with a large load.

Also, although not using a planetary gear clutch,
Japanese Patent Application Laid-Open No. 61-255330 discloses that a driven member is driven and driven using a one-way clutch, then reversed by a positioning signal, and the driven member is separated and held by a one-way clutch. A shutter driving mechanism adapted to be driven is disclosed.

[Problems to be Solved by the Invention] By the way, in a conventional rotary drive device using a planetary gear clutch described in the above-mentioned Japanese Patent Application Laid-Open No. 63-23138, a cam and a lever are required to select a load system to be driven. And a complicated structure such as a magnet are required, which causes not only a problem in cost and space but also a problem that it takes a long time from shutter release to start of exposure due to charging of the magnet. Only rotation in the direction is illustrated.

The technical means described in Japanese Patent Application Laid-Open No. 1-102439 is capable of rotating one load in both directions, but also requires complicated locking means including a cam, a lever and a magnet. It has the same disadvantages as the -23138 device.

The driving mechanism disclosed in Japanese Patent Application Laid-Open No. 61-255330 does not require a magnet or the like as in the prior arts described above, and is an excellent mechanism. However, the driving mechanism repeats forward rotation, reverse rotation, normal rotation, and reverse rotation during operation. The operation from the release to the completion of the exposure is performed, so the control of the motor is complicated, and a constant stroke is always required before the shutter is driven, and even if the extension of the lens is controlled immediately by the auto focus operation, However, there is a disadvantage that it takes a long time to operate the shutter.

Accordingly, an object of the present invention is to provide a rotary drive device which eliminates the above-mentioned disadvantages of the related art, has a small number of parts, does not require a special magnet or the like, and does not require extra time for switching or the like. To be.

[Means and Actions for Solving the Problems] A rotation driving device for a camera according to the present invention is a rotation driving device for a camera that transmits a rotational force by selectively switching at least two loads by using a planetary gear mechanism. , A rotary drive source, a sun gear driven by the rotary drive source,
A planetary gear meshing with the sun gear, a first rotating member pivotally supporting the planetary gear, a second rotating member having internal teeth meshing with the planetary gear, and moving in accordance with rotation of the first rotating member A first moving member, a second moving member that is moved in accordance with the rotation of the second rotating member, and that has a smaller load force than the first moving member, and a second moving member. An immovable stop member for stopping the movement in one direction at a predetermined position, and a means for determining the phase of the torque ripple of the rotary drive source at a predetermined position is provided on the first moving member side. It is characterized by the following.

Still further, a rotation drive device for a camera according to the present invention includes a rotation drive source, a differential mechanism driven by the rotation drive source and having a first drive output unit and a second drive output unit; A second moving member that is moved in accordance with the rotation of the drive output unit and is moved in two directions corresponding to the two directions of rotation of the second drive output unit; A shutter that operates in a predetermined position, an inactive stop member that restricts the movement of the second moving member at a predetermined position, and a first member that stops movement of the second moving member when the movement of the second moving member is restricted by the stop member. A first moving member that is rotated by the rotation output of the drive output unit;
And a lens that is moved in two directions.

Hereinafter, the present invention will be described with reference to the illustrated embodiments.

FIG. 1 shows a first embodiment of the present invention. In this embodiment, a rotary drive device including a planetary gear clutch 1 uses a shutter opening / closing mechanism 3 in a camera and a lens extension mechanism for autofocus. 2 and when the shutter opening / closing mechanism 3 is driven, the rotational driving force of the driving source in both directions is accurately transmitted.

The planetary gear clutch 1 is equally disposed around a sun gear 5 attached to an output shaft of a rotary drive source 4 composed of a reversible DC motor and meshing with the sun gear 5 while being engaged with the sun gear 5. Three planetary gears 6a, 6b, 6c
A plurality of planetary gears 6a to 6c are engaged with the internal teeth 7a, respectively, and are constituted by a second output gear 7 forming a second rotating member.

The second output gear 7 is formed of a ring-shaped gear having an internal tooth 7a and an external tooth 7b. The external tooth 7b includes a swing member 8 for transmitting a driving force to a shutter opening / closing mechanism 3 described later. It engages with sector gear 8a.

The planetary gears 6a to 6c are freely rotatably mounted on their support shafts 9a, 9b, 9c, respectively.
Each of the support shafts 9a to 9c has the same gear as the first output gear 10 which is disposed above the second output gear 7 and is a first rotating member.
The base ends are fixedly planted at equal intervals on the same circumference near the outer peripheral edge of the ten.

The first output gear 10 meshes with a focusing cam gear 11 that transmits a driving force to the lens feeding mechanism 2.

The lens feeding mechanism 2 includes a focusing cam gear.
An end face cam 11a having a ring shape in a plan view is integrally formed on the upper surface of 11, and a drive pin 12a as a cam follower is pressed against a cam surface of the end face cam 11a. The drive pin 12a is fixed to a lower end surface of a vertical arm 12b of the lens frame 12 movably fitted to a vertical support shaft 14 fixed to the camera body 20, and is wound around an upper portion of the support shaft 14. Armed vertical arm 12
Between the upper surface of b and the camera body 20, it is urged downward by a coil spring 13 exerting its extension elasticity, and presses against the cam surface.

The mirror frame 12 is formed by an inverted L-shaped frame, and a photographing lens 21 is attached to a tip of a horizontal arm 12c extending laterally from an upper portion of the vertical arm 12b. Further, the lens frame 12 is provided with a rotation stopping projection 12d projecting from the tip of the horizontal arm 12c, and the projection 12d is loosely sandwiched between the two vertical guide members 15a, 15b. The optical axis of the lens is held without rotating unnecessarily.

The focusing cam gear 11 and the lens frame 12 form a first moving member in the present invention.

On the other hand, the shutter opening / closing mechanism 3 is
A shutter composed of two sector blades 17a and 17b disposed on the optical axis O of the first and second movable members formed by the swing member 8 for driving the sector blades 17a and 17b to open and close; The main part is constituted by a stop member 16 which is a stopper for stopping the moving member 8 at the initial position.

The sector blades 17a, 17b are formed of thin plates having a wide sickle shape and are arranged so as to face each other, and their bases are rotatably supported by support shafts 18a, 18b. The sector drive pins 8b are made to pass through the common through holes of the sector opening / closing slit holes 17a 'and 17b' formed near each base. The sector drive pin 8b is fixedly planted on one arm of the swing member 8.

The oscillating member 8 is a portion that is closer to the right from the center and is swingably supported at the center of the sector gear 8a by a support shaft 19, and extends downward from the slit holes 17a 'and 17b'. The sector drive pins 8b are erected on one arm. On the opposite side of this one arm, the sector gear 8a centering on the support shaft 19 is formed, and the external gear 7b of the second output gear 7 meshes with the sector gear 8a. . Further, a contact portion 8c to the stop member 16 is formed at a portion of the one arm near the support shaft 19, and the swing member is moved to an initial position where the contact portion 8c contacts the stop member 16 in flat. 8 is stopped.

In this initial position, the sector drive pin 8b holds the shutter in a shutter closed state in which two sector blades 17a and 17b are overlapped.

In the thus configured rotary drive device of the present embodiment, when the motor as the rotary drive source 4 is driven to rotate clockwise, the sun gear 5 also rotates clockwise. Then, the rotational force of the sun gear 5 is transmitted to the planetary gears 6a, 6b, 6c,
The output gear 7 tries to rotate in the counterclockwise direction, and the sector gear 8a of the swing member 8 meshing with the external teeth 7b of the second output gear 7 tries to rotate in the clockwise direction. 8c abuts against the stop member 16 to prevent the swinging member 8 from rotating clockwise, so that the rotation of the second output gear 7 is also prevented. Further, when the sun gear 5 rotates clockwise, the planetary gears 6a, 6b, 6c revolve clockwise while rotating. When the planetary gears 6a, 6b, 6c revolve in this way, their respective shafts 9
Since a, 9b, and 9c also rotate together with the planetary gears 6a, 6b, and 6c, all the rotational force of the motor 4 is transmitted to the first output gear 10, whereby the focusing cam gear 11 rotates counterclockwise.

Then, the drive pin 12a pressed against the cam surface of the end cam 11a is pushed up, so that the photographing lens 21 attached to the lens frame 12 starts to be extended. When the lens is extended to a lens position calculated in advance based on the distance measurement data measured by the distance measuring means (not shown) while monitoring the position of the lens frame by means of the lens frame position detecting means (not shown), the motor 4 Rotation switches from clockwise to counterclockwise. When the motor 4 rotates in the counterclockwise direction, the rotational driving force tries to drive the cam gear 11 through the planetary gear clutch 1 in the clockwise direction. However, due to the clockwise driving load of the cam gear 11, the swing member 8
Since the driving load of the sector gear 8a in the counterclockwise direction is sufficiently light, the cam gear 11 does not rotate. Therefore, the rotation of the support shafts 9a, 9b, 9c of the planetary gears 6a, 6b, 6c fixed to the output gear 10 also stops. Then, the revolution of the planetary gears 6a, 6b, 6c stops, and the respective gears 6a, 6b, 6c rotate clockwise.
The output gear 7 is rotated clockwise. This rotational driving force is transmitted to the swing member 8 via the gear 8a, and the swing member 8 rotates counterclockwise. That is, it rotates in a direction away from the stop member 16. By this rotation, the slit holes 17a ', 17
The sector drive pin 8b fitted to b 'moves in the counterclockwise direction, the sector blades 17a and 17b rotate around the support shafts 18a and 18b, the photographing optical path opens, and exposure starts. Then, based on the data measured by the photometry means (not shown), the time for the proper exposure calculated in advance (the time from the start of the rotation of the motor 4 in the counterclockwise direction at the end of the lens extension) is calculated. Change the rotation from counterclockwise to clockwise. Then, the swing member 8 attempts to rotate clockwise, and the cam gear 11 attempts to rotate counterclockwise (lens extension direction). In this state, the load driving torque of the motor 4 for driving the rocking member 8 clockwise is sufficiently smaller than the load driving torque of the motor 4 for driving the cam gear 11 counterclockwise.
The first output gear 10 does not rotate due to the planetary gear clutch 1, the second output gear 7 rotates counterclockwise, and the swinging member 8 rotates clockwise. With this rotation, the sector drive pin 8b
Also returns clockwise, the sector blades 17a and 17b start closing, and when further rotated, the sector blades are completely closed. Further, the swing member 8 further rotates clockwise, and the contact portion 8c abuts on the stop member 16 so that the swing member 8 stops rotating. When the rotation of the swinging member 8 is stopped while the motor is driven, the driving force of the motor is entirely transmitted to the first output gear 10 by the clutch 1, and the cam gear 11 meshing with the first output gear 10 rotates counterclockwise. Then, the lens frame 12 is further extended, and after the vertex of the cam 11a, the lens frame 12 starts to be retracted. The motor 4 is stopped when the lens frame 2 comes to the reset position (the lowest position of the cam) while monitoring the lens frame position by the lens frame position detecting means (not shown). The load diagram of this series of operation sequences is shown in FIG.
It is shown in the figure. That is, the motor torque required to drive the first load of the lens feeding mechanism 2 is indicated by a solid line A,
The dotted line B indicates the motor torque required to drive the second load of the shutter opening / closing mechanism 3, and the second load is a stop member.
Becomes ∞ when locked by 16.

In the above-described embodiment, the terminal portions of the slit holes 17a 'and 17b' may be used as a stopper instead of the stop member 16.

By using the rotary drive in this manner, the lens can be extended and the sector can be opened and closed by one motor, the number of parts is small, and a shutter with a short time lag until the sector is opened after the lens is extended regardless of the amount of lens extension. Can be.

By the way, in the shutter of the type in which the sector blades are opened and closed by the reciprocating rotation of the motor as in the first embodiment, when the motor is rotated in a normal direction and then reversed, the kinetic energy of the rotary drive system increases, There is a delay in reversing. This is a major factor that makes it difficult to obtain high-speed time in a shutter of the type in which the sector blades are opened and closed by forward and reverse rotation of the motor.

To solve this problem, as shown in the rise characteristics of the DC motor in FIG. 2, if the motor is controlled in the initial range of the rise of the motor, that is, in the range of T shown in FIG. Since the kinetic energy of the camera is small, high-speed shutter time can be output. However, a new problem arises here.

As is well known, a DC motor rotates by repetition of attraction and repulsion of both an exciting coil and a magnetic pole. For example, the starting torque of a two-pole three-phase DC motor is shown in FIG. As shown in (B), the torque ripple which becomes six peaks by one rotation of the rotor is exhibited depending on the rotor position at the start of the start. Therefore, if it is attempted to control the motor at the beginning of the rise of the motor, the rise characteristics are not stable due to the rotor position at the start of the motor start. This variation causes variation in the exposure aperture due to the sector blade, and the EE
It is difficult to ensure accuracy.

Thus, the present invention solves this problem as follows. That is, this countermeasure is solved by engaging the check pawl lever 23 with the focusing cam gear 11 of the first embodiment as shown in FIG.

That is, a non-return claw 23 having a swinging fulcrum pivotally attached to a fixed shaft 24 is provided, and the non-return claw 23a at one arm end is connected to the cam gear 1
It is arranged so as to be disengaged from a part of one tooth 11b. Then, by applying a contractile coil spring 25 between the other arm 23b of the lever 23 and the immovable member, the check claw 23a is always locked to a part of the teeth 11b of the cam gear 11, and the focusing cam gear 11 Can rotate in the counterclockwise direction in which the lens frame 12 is extended, but cannot rotate in the opposite direction to the clockwise direction. Also, the interval A between the cam gear 11 and the non-return claw 23a is set, and the rotation amount of the motor required to drive (in this embodiment, one tooth of the cam gear 11) is m / 6 rotations (n is (Integer) is set.

With this configuration, after the extension of the lens frame 12 is completed,
The focusing cam gear 11 that rotates clockwise is a check pawl 23
The starting torque at the position where the rotation is blocked by a is
It will always be the same, regardless of the amount of feeding of 2. As a result, the same starting torque of the torque ripple in FIG. 3 can be used as the rising characteristic at the start of the rotation of the swinging member 8, so that the stable rising characteristic of the motor can be always obtained.

Therefore, in a shutter in which the lens frame 12 is extended and the shutter operation is performed by one motor, and the opening and closing operation of the sector blade is performed by the forward and reverse rotations of the motor, the motor is stabilized before the steady rotation, that is, in the initial rise. The shutter speed can be obtained at high speed.

The driving torque of the focusing cam gear 11 can be changed by setting the amount of force of the coil spring 25 in FIG. For example, if the coil spring 25 is strengthened,
Since the force by which the shutter 11 pushes the non-return claw 23a is increased, the relationship between the first load of the lens feeding mechanism 21 and the second load of the shutter opening / closing mechanism 3 is set as follows: first load> second load.
It is possible to set the load.

6 to 8 show an example of means for increasing the load of the lens feeding mechanism 2. FIG. That is, the end face cam 11a of the focusing cam gear 11, as shown in Figure 6, higher stepwise in a direction height of the cam surface is increased, the boundary of the stepped cam face 11a _1, 11a ₂ ...... Each of the sections is provided with a sawtooth-shaped inclined projection 11c which is inclined toward the lower side of the cam surface. On the other hand, the driving pin 12a ₁ for pressing the cam surface 11a _1, 11a ₂ ......, the shape of the tip corner portion at one side towards as shown in 7,8 Figure, the other side towards the round portion Formed so that
When it engages with the above-mentioned inclined projection 11c, it shifts to a high cam surface, but it is configured such that a corner cannot abut on a vertical wall of the inclined projection 11c to move to a low cam surface.

According to this structure, in the state where the cam 11 as shown in FIG. 8 is moved in the direction of the arrow, the driving pin 12a ₁ and the projection 11c
Is increased, and the driving torque of the focusing cam gear 11 for lifting the lens frame 12 is increased, so that the first load> the second load can be set, and the arrow in FIG. In the state where the cam 11 moves in the direction, the inclined projection 11c abuts on the driving pin 12a ₁ as described above, so that the focusing cam gear 11 cannot be reversed by the lens frame 12, and the second load is driven. become able to.

Moreover, in this configuration, the cam surface 11 shown in FIG.
a ₁ , 11a ₂ …… the motor rotation amount required for one pitch drive is n / 6
By setting the reduction ratio to be the rotation (n is an integer),
The torque ripple problem described above can also be solved.

FIG. 9 shows a rotary drive device according to a second embodiment of the present invention. In the second embodiment, the lens extension mechanism 2 in the first embodiment is replaced with a mechanism 30 for taking in and out a zoom lens in a tele-wide switching camera.

That is, the driving force of the first output gear 10, which is the first rotating member, is transmitted to the T / W switching gear 31, and a driving pin is provided on a part of the gear 31 near the outer peripheral edge. 31a has been planted. The drive pin 31a is fitted into a T / W switching long hole 32c of the support plate 32 holding the zoom lens 33. The support plate 32 holds the zoom lens 33 at the end near the optical axis O of the photographing lens, and guide holes 32a, 32b for moving the lens 33 on the optical axis O, and the above-described direction perpendicular to the holes. It has a long hole 32c, and the guide holes 32a, 32b are fitted to guide shafts 34a, 34b fixedly implanted in an immobile member.

 Other configurations are the same as in the first embodiment.

In the rotary drive device of the second embodiment configured as described above, when the first output gear 10 is driven and the T / W switching gear 31 rotates, the drive pin 31a also rotates. This pin 31a
Is rotated, the support plate 32 is linearly moved by the guide holes 32a and 32b by the T / W switching long hole 32c, and moves the magnification lens 33 onto the photographing lens optical axis O. When the zooming lens 33 aligns its optical axis with the projection lens optical axis O, the projection optical system enters the telephoto state. When the support plate 32 moves to the telephoto position, a teleposition detection switch (not shown) switches the support plate to the telephoto position. 32
Is detected, and at that time, the drive of the motor 4 is reversed.

Then, the driving force is transmitted to the shutter opening / closing mechanism 3, and thereafter, the same operation as that described in the first embodiment is performed.

Thus, the present invention can be applied to a rear converter.

[Effects of the Invention] As described above, according to the present invention, special electromagnetic components are not used unlike conventional devices, the number of parts is reduced, the cost is low, and no extra time is required for power switching. A camera rotational drive can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a rotary drive device according to a first embodiment of the present invention, FIG. 2 is a diagram showing a rising characteristic of a DC motor as a rotary drive source used in the rotary drive device, 4A and 4B are diagrams showing the torque ripple and the rotor position of the DC motor, respectively. FIG. 4 is a plan view of a main part of a means for setting the phase of the torque ripple of the rotary drive source to a predetermined position. FIG. 5 is a load diagram showing a series of operation sequences of the driving device of the first embodiment, and FIG. 6 is an essential part showing an example of means for increasing the load of the lens extension mechanism in the first embodiment. FIGS. 7 and 8 are enlarged views of the essential parts showing the operation of the means shown in FIG. 6, respectively. FIG. 9 is a perspective view of a rotary drive device showing a second embodiment of the present invention. FIG. 10 is a line showing a configuration when the planetary gear mechanism is used as a clutch. It is. DESCRIPTION OF SYMBOLS 1 ... Planetary gear clutch 2 ... Lens extension mechanism (1st load) 3 ... Shutter opening / closing mechanism (2nd load) 4 ... DC motor (Rotation drive source) 5 ... Sun gear 6a-6c ... Planet gear 7 second output gear (second rotating member) 8 swing member (second moving member) 8a sector gear (second moving member) 10 first output gear (first rotating member) 11 … Focus cam gear (first moving member) 16 …… Stop member

Claims (3)

(57) [Claims] 1. A rotary drive device for a camera for transmitting a rotary force by selectively switching at least two loads using a planetary gear mechanism, comprising: a rotary drive source; and a sun driven by the rotary drive source. A gear, a planetary gear meshing with the sun gear, a first rotating member pivotally supporting the planetary gear, a second rotating member having internal teeth meshing with the planetary gear, and a rotation of the first rotating member. A first moving member that is moved according to the first moving member, and a first moving member that is moved according to the rotation of the second rotating member.
A second moving member to which a load force smaller than the load force applied to the moving member is applied; and an immovable stop member for stopping the movement of the second moving member in one direction at a predetermined position. Camera rotation drive. 2. A camera rotation driving device according to claim 1, wherein means for setting the phase of the torque ripple of the rotation driving source at a predetermined position is provided on the first moving member side. 3. A rotary drive source, a differential mechanism driven by the rotary drive source and having a first drive output section and a second drive output section, and according to the rotation of the second drive output section. A second moving member that is moved and moved in two directions corresponding to the two directions of rotation of the second drive output unit; a shutter that operates in conjunction with the operation of the second moving member; An immovable stop member for restricting the movement of the second moving member at a predetermined position; and a rotation output by the rotation output of the first drive output portion when the movement of the second moving member is restricted by the stop member. And a lens that is moved in two directions by rotation of the first moving member in one direction.