JP2000310810A - Driving mechanism for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To withstand the external force exerted on a lens barrel with miniaturized constitution. SOLUTION: When a lens is advanced, planet gears 10 and 11 are revolved counterclockwise and engaged with a gear to be driven 12 so as to transmit driving force to the lens barrel. When the lens is retreated, the gears 10 and 11 are revolved clockwise and engaged with the gear 12 to transmit the driving force to the lens barrel. At the standby time of photographing, the gears 10 and 11 are revolved clockwise and get in a state where they are engaged with the gear 12 or a state where they are not engaged with the gear 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera driving mechanism.

[0002]

2. Description of the Related Art Conventionally, in a zoom lens or the like, when the tip of the lens barrel is pushed or an impact is applied, the lens barrel and a transmission gear must be made strong or a transmission gear train has to be provided so as to withstand this. Was equipped with a shock absorbing slip clutch.

[0003] However, both the former and the latter lead to an increase in the size of the equipment. Particularly when a slip clutch is provided, the slip torque must be set to be larger than the maximum driving torque of the lens barrel.
In addition, since the impact force at which the clutch operates is increased, the impact strength of the lens barrel itself must be ensured after all.

[0004]

Accordingly, a technical problem to be solved by the present invention is to provide a drive mechanism for a camera which can withstand an external force applied to a lens barrel with a reduced size. is there.

[0005]

The present invention provides a camera driving mechanism having the following configuration in order to solve the above technical problems.

The drive mechanism of the camera includes a drive source, a transmission mechanism for transmitting the output of the drive source to the lens barrel for moving the lens in the lens barrel forward and backward, and a planetary gear provided in the transmission mechanism. Prepare. When the lens is advanced, the planetary gear revolves in the first direction and engages with the driven gear to transmit driving force to the lens barrel. When the lens is retracted, the planetary gear revolves in the second direction and engages with the driven gear to transmit a driving force to the lens barrel. At the time of shooting standby, the planetary gear is engaged with the driven gear in the second direction, or the planetary gear is not engaged with the driven gear.

In the above arrangement, the lens barrel is driven by the rotation of the driven gear. When you move the lens forward,
Regardless of the configuration in which the same planetary gear is engaged with the same driven gear and the configuration in which a different planetary gear is engaged with the same driven gear, , Or different planetary gears may engage different driven gears. At the time of shooting standby, the planetary gear is separated from the driven gear, or the planetary gear is engaged with the driven gear in the second direction.

In a state where the planetary gear is separated from the driven gear at the time of photographing standby, external force to the lens barrel is transmitted to the driven gear, but is transmitted to the front of the planetary gear (to the drive source side). Absent. Therefore, since the driving source side does not become a resistance, the external force can be absorbed by moving the lens barrel.

When the planetary gear is kept on standby in the second direction, that is, in the direction for retracting the lens, in a state of engaging with the driven gear, when the external force in the direction for retracting the lens acts, the planetary gear is disengaged. When the drive gear starts to rotate, tooth surface pressure acts on the driven gear in a direction to disengage with the planetary gear. The rotation is not transmitted to the source side. Thereby, it is possible to release the external force.

What is of concern in the direction of external force on the lens barrel is that
It is a direction to retract the lens, and it is expected that the frequency is relatively high, such as bumping when carrying, but external force in this direction can be released by, for example, rotation of the lens barrel,
Since no slip clutch is required for this purpose, there is no limitation on the magnitude of the acting impact force, and the design constraints of the lens barrel can be reduced, and the size can be reduced.

Therefore, it is possible to endure an external force applied to the lens barrel with a miniaturized configuration.

In the above configuration, a planetary mechanism is used, but it is also possible to use a clutch mechanism.

That is, the drive mechanism of the camera includes a drive source, a transmission mechanism for transmitting the output of the drive source to the lens barrel for moving the lens in the lens barrel back and forth, and a clutch mechanism provided in the transmission mechanism. Is provided. The clutch mechanism has a function of switching whether the output of the drive source is transmitted to the lens barrel or not, and when the photographing is in a standby state, the clutch is in a non-transmission state.

According to the above arrangement, the clutch is set to the non-transmission state during the standby for photographing, so that even if an external force is applied from the lens barrel, the transmission to the drive source side is cut off by the clutch. Can be released by rotating.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A camera driving mechanism according to an embodiment of the present invention will be described below with reference to the drawings.

First, the basic configuration of the camera 100 will be described.
This will be described with reference to the front view of FIG.

At the approximate center of the camera 100, there is provided a so-called zoom focus type lens barrel 101 constituted by a plurality of lens groups. In the figure, 102 is a finder objective lens, 103 is a finder eyepiece, 1
04 is a projection lens for distance measurement, 105 is a light-receiving lens for distance measurement,
Reference numeral 106 denotes a flash light emitting unit, 107 denotes a main condenser, 108 denotes a cartridge chamber, 109 denotes a cartridge chamber cover, 110 denotes a spool chamber, 111 denotes a hatched portion for deceleration and switching of a driving system, 112 denotes a battery, and 13 denotes a lens barrel driving gear. It is. Drive source motor (not shown in this figure)
Is disposed in the spool chamber 110, and the output from the motor is transmitted to each mechanism using the deceleration and switching space 111 of the drive system.

The camera driving mechanism is located in the space 111,
It is configured as shown in the main part plan view of FIG. 2 and the main part plan view of FIG.

That is, the motor 1 is disposed inside the spool 20. 2 is a motor pinion. A friction mechanism is formed by the gears 3 and 4 and the spring 5 to prevent an excessive load on the gear train. Normally, the gears are transmitted to gears 3, 4, and 6, and when an excessive load is applied, transmission to gears 4 and thereafter is not performed by the action of friction. Reference numerals 6 and 7 denote step gears, 8 denotes an idle gear, 9 denotes a sun gear, 10 and 11 denote planetary gears, and 12 denotes a lens barrel input gear. The output of the motor is reduced and input to the sun gear 9. The planet gears 10 and 11 are held by a carrier 23.

FIG. 2 shows that the motor 1 is turned clockwise (hereinafter referred to as "clockwise").
"CW". ), The planetary gear revolves in a counterclockwise direction (hereinafter, referred to as “CCW”), and transmission is performed to 12. Planet 11 is not in engagement with the driven gear. A bevel gear 12 is provided at the upper part of the gear 12, and the rotation of the rotating shaft is changed to a right angle to rotate the lens barrel gear 13, and the rotation is transmitted to the lens barrel 101. Inside 101, the rotational movement is converted into the linear movement of the lens by the cam means, and the lens moves forward and backward. In this state, the lens moves in the telephoto direction.
The cam inside 1 is set.

The cam 12a, 12b is provided integrally with the cam 12, and the follower portion 24a of the swing lever 24 is pressed against the cams 12a, 12b by the urging force of a spring 28. Since this cam rotates while the lens barrel 101 is being driven, 24 repeatedly swings. The locking lever 30 is configured to rotate integrally with the rocking lever 24 by means of the swing lever claws 24b and 24c. Reference numeral 25 denotes a contact piece attached to 24, so that a state in which 24 rides on the cam 12a (the cam switch 1 is ON) and a state in which the 24 drops on the cam 12b (cam switch 2 is ON) can be detected by the pattern of the substrate 26. Has become. When the cam 24a rides on the cam 12a, the locking surfaces 30a and 30b of the claw portions of the locking lever 30 are
The vehicle enters the revolution trajectory to lock one rotation shaft. Reference numeral 21 denotes a pulse plate, and the amount of rotation of the motor 1 can be known by the photo interrupter 22.

FIG. 4 shows the relationship between the rotation angle of the lens barrel 101 rotated by 13 and each position. The lens barrel 101 has a known so-called zoom focus type configuration,
While the lens 1 is driven from the wide end to the tele end, a focus section and a zoom section are sequentially provided. In this example, there are four standby positions at which photographing is possible, and W, M1, M
2, referred to as T (the thick line in the figure). At each standby position,
When the release operation is performed, the lens barrel 101 is moved forward to the telephoto side by an extension amount corresponding to the output of the distance measurement. At this time, at a position slightly advanced from the standby position, a signal of a reference position is obtained by an encoder provided inside the lens barrel 101 (broken line portion in the figure), and pulse counting is started by 22 and a predetermined position is reached. Stop.

FIG. 5 shows an example of the encoder. Along with the movement of the lens, a contact piece (not shown) straddling pattern 1 and pattern 2 moves in the horizontal direction in the figure. The portion where the pattern 1 is embedded in the comb shape is the reference switch section, and when the signal of the pattern 1 changes from H to L by the contact piece, the pulse counting is started. The hatched portion (downward right) in FIG. 4 indicates the range in which the cam switch 1 is turned ON, and the cam surface for driving the swing lever 24 is the lens barrel input gear 1
2, the lens barrel 101 is periodically turned on while the lens barrel 101 is driven from the retracted position to the telephoto end. The shaded area rising to the right is the section in the middle of pushing up the swing lever,
During this time, neither the cam switch 1 nor the cam switch 2 is turned on. In other sections, the swing lever is in a depressed state, and the cam switch 2 is ON.

As shown in FIG. 4, each of the standby positions, the retracted end, and the telephoto end are in a state where the swinging lever is lowered, and the locking surfaces 30a and 30b of the claw portions of the locking lever 30 are the orbits of the planetary gear. It is in a more retracted position. Further, since the position of the lens barrel 101 and the cam switch correspond one-to-one, if space allows, the cam switch pattern and the encoder pattern can be formed on the same substrate.

Reference numerals 14, 16, and 18 denote gears that are transmitted when the revolution of the planetary gears is regulated. When the rotation of the gear 14 is performed, the rotation is transmitted to the fork portion in the upper portion of the cartridge chamber via the rotation 15. When 16 is rotated, it is similarly transmitted to the fork via 15. When 18 is rotated, 19
The spool 20 is rotated via.

Next, the operation will be described.

When a main switch (not shown) is turned on in the collapsed state, the motor rotates to CW, and the planetary gears 10 and 11 revolve to CCW.
Are transmitted to the lens barrel 101 and the lens barrel 101 moves forward. The planetary gear 11 rotates without meshing with the transmitted gear. As shown in FIG. 5, the area near the collapsed portion has a large pattern 1 area, and since the ON time is longer than the ON time of the reference switch, it can be identified that the lens is in the collapsed area. Since the signal changes from L to H when approaching the wide end, pulse counting is started, and the motor is stopped at the standby position at the wide end. With this, the lens barrel 101 is set to the wide state. After that, the motor is rotated by a small amount to CCW. Then, the planetary gears 10, 11 are C
W slightly revolves to the state shown in FIG.
Until 0, only the main part of the switching mechanism is displayed). Gears 10 and 1
Although the teeth of No. 4 make contact, the film is not driven because the load of the film is sufficiently heavy compared to the rotational torque of the planetary gear. Hereinafter, this position is set in the photographing standby state. This effect will be described later.

During driving from the retracted position to the wide end, the cam switch 1 is once turned on, but is turned off again at the wide position, and the locking lever 30 is in the retracted position.

When the zoom operation lever (not shown) is operated to the telephoto side, the motor rotates to CW, and the planet 10 revolves and starts transmitting to the planet 12 again. When you release your hand from the zoom control lever, the motor stops at the nearest tele side standby position. When the zoom operation lever is operated to the W side, the motor revolves to CCW, the planets 10 and 11 rotate to CW, and 11 engages with 12 to move the lens barrel 101 to the retreating side (FIG. 7). The planetary gear 10 rotates without meshing with the transmitted gear. When you release your hand from the zoom control lever, the motor stops at the closest wide-side standby position. Then, to move to the standby position (FIG. 6), the motor is slightly rotated to CCW. Alternatively, after driving in the W direction, it may be possible to stand by for photographing in the state of FIG. As described above, since the locking lever 30 is in the standby position in the standby position, the planets 10 and 11 are not restricted from revolving, and can be driven to tele or wide only by switching the rotation direction of the motor according to the zoom operation. Can be performed.

When the release operation is performed, the motor is rotated to CW, the lens is extended by the engagement of the planets 10 and 12, the lens is stopped at a predetermined position corresponding to the distance measurement output, and the shutter is operated. Depending on the stop position, the cam switch 2 may be OFF or ON. When the cam switch 2 is OFF, after the shutter operation, the motor is rotated to CW and the cam switch 2 is turned OFF.
The lens barrel 101 is extended until N is reached. Here, the motor is reversed and the cam switch 1 is turned on (the locking lever 30 enters).
Until the lens barrel 101 is retracted. When the motor is reversed again at this position and rotated to CW, the planetary gears 10, 11
Revolves in CCW, but the rotation shaft of the gear 31 comes into contact with the locking surface 30b of the locking lever 30 to restrict the revolution (FIG. 9). 9, 10, 16 and 9, 11, 18 are arranged in a straight line, and when the rotation of the motor is continued, the rotation is transmitted to 16, 18. Spools 20 are transmitted from 18 to 19 and 20, and the film is wound up. 16
, And transmitted to the fork, but the peripheral speed on the spool is set to be faster than the film feeding speed, and this difference in peripheral speed is absorbed by a one-way clutch or the like.

After sending one frame, the motor is stopped and CCW
To rotate. The planets 10 and 11 revolve in CW, and the rotation axis of the gear 31 is separated from the locking surface 30b. 11 engages with 12, and the lens barrel 101 is driven in the retracting direction. Stop the motor when it reaches the standby position.

When the cartridge is loaded and the initial loading is started, the lens barrel 101 is extended and stopped when the cam switch 1 is turned on. Here, when the motor is reversed, the rotation shaft of the gear 31 comes into contact with the locking surface 30a, and the revolution is restricted. At this position, the positions 9, 10, and 14 are arranged in a straight line, and when the rotation of the motor is continued, the rotation is transmitted to 14, 15, and the fork. Since 15 rotates in a direction opposite to the rotation direction of 15 during the above-described winding, the fork rotates to the rewind side (FIG. 10). During this time, information on the data disk on the cartridge is read and the motor is inverted.
The rotation shaft of the gear 31 is separated from the locking surface 30a, and the gear 10
Are engaged with each other, and the lens barrel 101 is extended. When the cam switch 2 is turned on, the motor 1 is reversed and the lens barrel 101 is retracted until the cam switch 1 is turned on. Here, when the motor 1 is reversed, a thrust state is obtained (same as FIG. 9). The fork and the spool rotate simultaneously, and the film is fed out of the cartridge. When the film is wound around the spool, the peripheral speed of the spool becomes faster than the feeding speed, and the peripheral speed is absorbed by means such as the one-way clutch. After the thrust, the motor is reversed and the lens barrel 10
Step 1 is repeated, and stops at the standby position.

The rewinding operation is the same as the operation for reading a data disk at the time of initial loading. The motor may be reversed after the lens barrel 101 is once pulled out from the cam switch 2 ON until the cam switch 1 is turned ON.

Next, measures against vibration and impact will be described.

When a load such as an impact is applied to the tip of the lens barrel 101 in a state where the lens barrel 101 protrudes from the body, the load in the optical axis direction is converted into a rotational force via an internal cam and turns the gear of the drive system. Force is generated. This often leads to gear breakage, and in the conventional zoom lens barrel, sufficient gear strength has been ensured or a clutch for absorbing shock has been provided. All of these lead to increased costs and space.

In this embodiment, in the photographing standby state, the planetary gears are separated from each other (FIG. 6), or they are kept in a position to be driven wide. If you want to keep it apart,
The external force to 01 is not transmitted beyond 12 and the external force can be absorbed by moving the lens barrel 101. The concern in the direction of the external force with respect to the lens barrel is the collapsible side direction, which is expected to be relatively frequent such as hitting when carrying. If the planet is kept on standby on the wide side, when external force acts on the retracted side, when 12 starts to rotate, the tooth surface pressure acts in the direction to disengage 11 from 12 and eventually the load is applied to the gears after 12 Is not transmitted. Thereby, it is possible to release the external force.

However, if the lens barrel 101 moves too easily, there is a problem in practical use. Therefore, the friction spring 29 is applied to the gear 12. The amount of force of this friction may be a very small amount such that the lens barrel 101 does not inadvertently move.

If the lens barrel 101 is pushed in or pulled out from the standby position, the above-mentioned reference switch and cam switch are monitored and detected. For example, when the lens barrel 101 is pulled out, FIG.
As can be seen from the above, the reference switch is turned on. When pushed, the cam switch 1 is turned on. That is, the moving direction of the lens barrel 101 is determined based on which switch is turned on first, and the number of times the switch is turned on is counted.
The position after the movement can be determined. Therefore, it is possible to return to the original position or to perform predetermined error processing. With a small displacement, the switch does not change and detection cannot be performed, but at the time of focus, after detecting the reference switch,
Since the pulse count starts, after focusing ends,
The position where the lens barrel 101 stops does not change, and there is no problem in shooting.

As described above, the external load on the lens barrel can be released.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

[Brief description of the drawings]

FIG. 1 is a front view of a camera according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part of a driving mechanism of the camera according to the embodiment of the present invention.

FIG. 3 is a front view of a main part of the drive mechanism of FIG. 2;

4 is an explanatory diagram of a relationship between driving of a driving mechanism in FIG. 2 and a lens barrel rotation angle.

FIG. 5 is a plan view of an encoder of the drive mechanism of FIG.

FIG. 6 is a plan view of a main part of the drive mechanism of FIG. 2;

FIG. 7 is a plan view of a main part of the drive mechanism of FIG. 2;

FIG. 8 is a plan view of a main part of the drive mechanism of FIG. 2;

FIG. 9 is a plan view of a main part of the drive mechanism of FIG. 2;

FIG. 10 is a plan view of a main part of the drive mechanism of FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 motor 2 motor pinion 3,4 gear 6,7 step gear 8 idle gear 9 sun gear 10,11 planetary gear 12 lens barrel input gear 12a, 12b cam 13 lens barrel drive gear 14-19 gear 20 spool 21 pulse plate 22 photo Interrupter 23 Carrier 24 Swing lever 24a Follower portion 24b, 24c Claw 25 Contact piece 26 Substrate 28 Spring 29 Friction spring 30 Locking lever 30a, 30b Locking surface 31 Planetary gear 100 Camera 101 Lens barrel 102 Finder objective lens 103 Finder eyepiece 104 Distance-measuring projection lens 105 Distance-measuring light-receiving lens 106 Flash light emitting section 107 Main condenser 108 Cartridge chamber 109 Cartridge chamber lid 110 Spool chamber 111 (shaded area) Drive system space 11 Battery

Claims (2)

[Claims] 1. A drive source, and a transmission mechanism for transmitting an output of the drive source to the lens barrel for moving the lens in the lens barrel forward and backward;
A planetary gear provided in the transmission mechanism, and when the lens is advanced, the planetary gear revolves in a first direction and engages with a driven gear to transmit driving force to the lens barrel; When retracting, the planetary gear revolves in the second direction and engages with the driven gear to transmit driving force to the lens barrel. At the time of standby for photographing, the planetary gear rotates with the driven gear in the second direction. Engaged state, or characterized in that the planetary gear is in a state not engaged with the driven gear,
Camera drive mechanism. A driving mechanism for transmitting an output of the driving source to the lens barrel for moving the lens in the lens barrel forward and backward; and a clutch mechanism provided in the transmission mechanism. Has a function of switching whether or not to transmit the output of the drive source to the lens barrel.
A drive mechanism for a camera, wherein the clutch is set in a non-transmission state.