JPH0277707A - Lens barrel incorporated with motor - Google Patents

Abstract

PURPOSE:To adjust the backlash of the focusing large gear of a rotary helicoid and an output gear properly by providing a roll member to the shaft of the output gear and making the roll member abut on the large-outer-diameter part of the rotary helicoid by a backlash adjusting means. CONSTITUTION:When the lens barrel which is assembled almost completely is viewed from in front of it, the bent part 19b of a cam ring 19 for adjustment is exposed partially to the internal surface of a fixed external cylinder, so when this part is moved in the circumferential direction with a screwdriver, etc., a tapered cam part 19b at the tip presses a collar 21 in the radial direction of the optical axis to displace the whole motor gear head unit inward by a small quantity. At such a time, the roll member 14a provided to the output gear abuts on the large-diameter part 10c of the rotary helicoid 10, so the output gear 14 accurately engages the large focusing gear 10b provided to the outer periphery of the rotary helicoid 10, so that a proper backlash quantity is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a backlash adjustment between a motor cache output cap of a lens barrel incorporating an uncircumcised drive motor and a large focusing gear.

[Prior art] Conventionally, this type of device was either unadjusted, or the output gear was mounted in the mounting hole of the motor gear head unit, and the unit was mounted by slightly shifting the mounting position.
I was adjusting the consistency with the large focusing gear.

In addition, as shown in Utility Model Application No. 62-704, an adjustment cam link having a tapered cam portion at the tip is provided on the inner periphery of the fixed lens barrel, so that the output gear and the large focus gear can be adjusted. A type that can continuously fine-tune the hair loss has also been proposed. This type has the advantage of being easier to adjust, since it can be adjusted from the outside after the lens barrel is assembled.

[Problem that the invention seeks to solve] However,
In any of the above conventional examples, the sharpness is not adjusted by directly looking at the engagement between the output gear and the large focusing gear, but as one of the adjustment methods, the automatic focusing drive At present, the current value is detected by detecting the magnitude of the current value of the motor when the motor is rotated, and adjusting the voltage so that the current value matches the standard value.

With this method, there will be error factors such as variations in the coil resistance of the motor itself, variations in the applied power, etc. Also, variations in the load torque of the lens barrel will be added, and the output current value will not be stable. It wasn't something I liked. Another method is to manage the amount of polishing by feeling it, instead of managing the amount of polishing based on the magnitude of the current value. However, with this method, the only way to judge the amount of backlash caused by the tweezers, the smoothness of the movement, etc. is by feel, and there is a risk that there will be considerable variation due to differences in the judge.

[Means for solving the problem] According to the present invention, when adjusting the hacklash caused by the engagement between the large focus gear on the rotating helicoid and the output gear from the motor side, when the hacklash is adjusted to an appropriate amount, the By providing a member that regulates the adjustment operation, the hacklash can be adjusted appropriately, with the apparent meshing of the gears being the same as when adjusting by directly looking at them, and the adjustment also being made in contact with the regulating member. It is simple and easy to manage the honeysuckle.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention, and FIG. 1 is a sectional view of a lens barrel to which the present invention is applied.

la is a fixed outer cylinder, which is fixed at its rear end with a mount fitting 2 or a screw 3 for coupling with a camera (not shown). A fixed inner cylinder 1b is connected to the fixed outer cylinder 1a via a flange portion. 4 is a zoom operation member, fixed inner cylinder 1
It is connected to a cam cylinder 5 rotatably fitted on the outside of b. Reference numeral 6 denotes a holding frame for the rear group lens L2, which is held movably in a straight line inside the fixed inner cylinder 1b. 7 is a front lens group L which is also held movably in a straight line inside the fixed inner cylinder lb.
It is a moving ring of □. There is a helicoid part 7 inside the moving ring 7.
a is provided and is screwed into the helicoid portion 8a of the front group lens holding frame 8. Reference numeral 9 denotes a rotation transmission pin implanted at the tip of the front group lens holding frame 8, which transmits the rotation of the rotating helical element 1O. A helicoid portion 10a is provided on the inner periphery of the rotating helicoid 10, and is threadedly engaged with a helicoid portion 1c provided on the outer periphery of the fixed inner cylinder 1b. lOb is a large focusing gear provided on the outer periphery of the rotating helicoid 10, and is engaged with an output gear 14 rotated from a focusing drive motor 11 via a reduction gear train 12 and a manual focusing/automatic focusing switching clutch 13. There is. Reference numeral 14a denotes a roller member which is pivotally fitted to the output gear 14 so as to be rotatable. The output gear 14 and the large focusing gear portion 10b are set to have proper gear meshing. In other words, the amount of backup becomes appropriate. The thrust removal of the roller member 14a is prevented by a well-known method such as a tightening washer.

Reference numeral 15 denotes a manual focus operation member disposed outside the fixed outer cylinder 1a, and has a gear portion 15a on the inner periphery that meshes with a part of the reduction gear train 12. Reference numeral 16 denotes a signal contact, which supplies power to the autofocus drive motor 11 and the electromagnetically driven aperture unit 18 from the camera body via a flexible printed board 17. When this lens is attached to a camera (not shown) and the zoom operation □ member 4 is rotated, the cam cylinder 5 rotates, and a known mechanism causes the holding frame 6 of the rear group lens L2 to move backward, and at the same time, the moving ring 7 moves forward. The front group lens holding frame 8 screwed thereto also moves forward, and the telephoto shooting state shown in the upper half of FIG. 1 shifts to the wide-angle shooting state shown in the lower half. Therefore,
When the release button is lightly pressed one step, a focus drive signal is applied to the automatic focus drive motor 11 from the distance measuring circuit built into the camera body via the signal contact 16 and the flexible printed board 17. The rotation of the motor 11 is transmitted to the output gear 14 via a reduction gear train 12 and a switching clutch 13. The rotation of the output gear 14 is transmitted to the gear portion 10b of the rotating helicoid 10 that meshes with the output gear 14, and the rotating helicoid lO is paid out by the lead of the helicoid 10a.

The rotation of the rotating helicoid 10 is transmitted to the front group lens holding frame 8 by the rotation transmission pin 9, and the front group lens holding frame 8 is extended by the lead of the helicoid 8a. Front group lens L
, when the focus position is reached, a focus drive stop signal is issued from the camera side, and the automatic focus drive motor 1 is stopped. At the same time, the light inside the viewfinder lights up to indicate that the focus is complete. Now, when the release button is pressed deeper, a pre-calculated aperture drive signal is generated from the camera side, transmitted to the electromagnetic drive aperture unit 18 via the signal contact 16 and the flexible printed board 17, and the aperture is narrowed down to a predetermined value. At the same time, the mirror also begins to rise. When the mirror rises one level, the shutter film moves and the exposure is completed.

FIG. 2 is a perspective view of the essential parts of the hack rack adjustment mechanism, and 19 is a cam link for adjusting the hack rack. The adjustment cam link 19 has a C-shaped main body and a tapered cam portion 19a at the tip.
and a bent portion 19b, and is rotatably held in a circumferential groove provided on the inner periphery of the fixed outer cylinder 1a.

Reference numeral 20 denotes the base plate of the motor gear head unit, and the above-mentioned automatic focus drive motor 11° reduction gear train 12.
The switching clutch 13 and the output gear 14 are integrally assembled. Reference numeral 21 denotes a collar fitted with the rotating shaft of the output gear 14, the base of which is caulked to the motor gear head unit base plate 20. The entire motor gear head unit is bolted to the lens barrel body via a rubber lash, so it can be moved by minute amounts. If you look at the lens barrel that has almost been assembled from the front, you will see that part of the bent part 19b of the adjustment cam link 19 is exposed on the inner surface of the fixed outer barrel 1a. Move this part in the circumferential direction with a screwdriver or the like. The tapered cam portion 19a at the tip or the collar 21 is pressed in the radial direction of the optical axis, and the entire motor gear head unit is displaced inward by a minute amount. Then, by bringing the roller member 14a provided on the output gear 14 into contact with the large outer diameter portion 10c of the rotating helicoid 10 (see FIG. 3), the roller members 14a provided on the output gear 14 and the rotating helicoid 10 are The large focusing gear 10b is configured to have proper gear meshing, that is, to provide an appropriate amount of sharpening. By the way, when the roller member 14a comes into contact with the large outer diameter portion 10c of the rotating helicoid 10, the output gear 14 is gear-coupled with the large focus gear 10b of the rotating helicoid 10. When the output gear 14 rotates, the roller member also rotates about the axis of the output gear 14 since it is in contact with the large outer diameter portion 10c.

[Effects of the Invention] As explained above, when the roller member is provided on the shaft of the output gear from the motor and the roller member is brought into contact with the large outer diameter portion of the rotating helicoid, the focusing large diameter of the rotating helicoid 1~ By configuring the gear to have an appropriate amount of backlash between the output gear and the output gear, when adjusting the backlash, it is possible to adjust the backlash with the same accuracy as the method of adjusting by directly looking at the apparent gear engagement, and the current value can be adjusted as accurately as the conventional method. The adjustment accuracy is significantly improved compared to the comparative sense. Further, there is no need for fine adjustment of the backup ratio. In addition, since the amount of adjustment is restricted by the roller member and the large outer diameter of the rotating helical coil 1~, there is a risk that the backlash between the large focus gear and the output gear will become too small, causing the gears to bite together. It disappears. Since this method adjusts the thickness by bringing the roller member into contact with the large outer diameter of the rotating helicoid, it is easy to adjust, and it is easy to assemble and manage the thickness, and the effect is tremendous. It is something.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an interchangeable lens barrel according to the present invention, Fig. 2 is a perspective view of the main parts of the backlash adjustment mechanism according to the present invention, and Fig. 3 is a focus magnification of a rotating helicoid portion according to the present invention. 14 is an output gear, 14a is a roller member 19, and 19a is an adjustment cam ring (backlash adjustment means). The taper cam part 20 is a motor gear head unit base plate 21 is a collar.

Claims (1)

[Claims] (1) A large focusing gear that rotates during a focusing operation; an output gear that receives rotation from an automatic focusing drive motor and transmits the rotation to the large focusing gear; and the output gear and the large focusing gear. and a lens barrel with a built-in motor, the roller member being configured to be rotatable on the rotational axis of the output gear, while the large focusing gear or A member that rotates coaxially with the large focusing gear is provided with a large diameter portion that can come into contact with the roller member, and when the large diameter portion and the roller member come into contact, the output gear and the large focusing gear are connected. A lens barrel with a built-in motor, characterized by a gear connection with a predetermined backlash.