JP2003121726A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AF lens barrel having constitution that the rotational adjusting angle of an oscillatory wave motor or a manual adjusting angle can be freely set and giving optimum manual operational feeling. SOLUTION: In a full time manual mechanism having structure where the output ring of a progressive wave motor is meshed with the inside of one of planet gears divided into two in a thickness direction and each having frictional resistance, and a manual operating ring is meshed with the outside of the other, friction between two-divided planet gears is set smaller than the friction between the rotor and the stator of a motor, whereby driving force from the motor or manual operational force at the lens moving terminal of a lens moving ring is released by sliding rotation between the planet gears, and contact pressure between the rotor and the stator of the motor is independently adjusted in order to bring out maximum efficiency, and other driving systems are not influenced by such adjustment.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system camera, and more particularly to an interchangeable lens barrel of a single-lens reflex camera, and more particularly to an AF single-lens reflex camera capable of manually adjusting a distance ring. It relates to a lens barrel. 2. Description of the Related Art In a manual adjustment mechanism of a motor-in-body type or motor-in-lens type AF-only interchangeable lens, a method is generally used in which a clutch is installed to switch between an interlocking system of a driving motor and a manual interlocking system. However, there is a problem due to the inconvenience of the switching operation during use and the timing of shooting. As a remedy for this, the lens moving ring carries a rotatable roller centered on a radial line perpendicular to the optical axis as a method that can be manually adjusted at any time in conjunction with the vibration wave motor drive The roller is rotated from both the rotor and the manual operation ring to actuate the lens moving ring by pressing and holding the roller in the optical axis direction between the rotor and the manual operation ring.
253214, JP-A-2-253217. A large number of spherical rolling elements individually and rotatably fitted closely to the periphery of a rotating ring member for rotating a lens moving ring are pressed and held between a motor-side driving ring and a manual operating ring, and spherical rolling elements are pressed from both sides. JP-A-2-253210 in which a lens moving ring is operated by rotating a lens. Some manuals have been proposed, such as Japanese Patent Application Laid-Open No. 4-191806, in which the entire drive mechanism including the stator, rotor, and lens moving ring held by pressure is manually rotated. [0003] However, these methods have a pressure contact structure utilizing the pressurization required for the operation of the vibration wave motor. Since it relies on a pressure spring in the motor, it is difficult to adjust the frictional force of each of the sliding surfaces of these mechanisms, and there has been a problem in the reliability of power transmission.
Also, high working precision is required for the surfaces of the sliding member and the rollers, and there are also many restrictions on the material due to the friction coefficient, which has been a major design obstacle, including an increase in cost. Furthermore, in the conventional method, the rotation adjustment angle and the manual adjustment angle of the vibration wave motor are almost equal, and the rotation adjustment angle and the manual adjustment angle of the vibration wave motor can be freely selected depending on the problem on the motor torque and the feel at the time of manual adjustment. , Could not be set. [0004] In order to solve the above problems,
A guide ring rotatable around an optical axis interlocked with a focus adjustment lens moving ring and a planetary gear installed on the guide ring are divided into two gears having different numbers of teeth, and one of the two gears is driven by the vibration wave motor centering on the planetary gear. The ring and the other are connected to a manually operated ring, adopting an independent structure obtained by bearings received on the rotor side and springs from the stator side so that the optimum contact pressure of the vibration wave motor does not affect other interlocking systems, A highly reliable full-time manual mechanism was obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A full-time manual mechanism according to the present invention is divided into two parts in the thickness direction, and meshes with one of planetary gears having frictional resistance with an output ring of a traveling wave motor inside. If the friction between the two divided planetary gears is set to be smaller than the friction between the rotor and the stator of the motor,
The driving force from the motor and the manual operation force at the lens moving end of the lens moving ring can be released by sliding rotation between the planetary gears, and the contact pressure between the rotor and the stator of the motor is independent to maximize the efficiency. The adjustment does not affect other drive systems. The best embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the construction of a lens barrel according to the present invention, FIG. 2 is an exploded perspective view of an annular type traveling wave motor, and FIG. 3 is a guide ring, a planetary gear installed there and an interlocking mechanism. It is a detailed perspective view. In the drawings, the same members are denoted by the same reference numerals. In FIG. 1, reference numeral 12 denotes a fixed barrel of a lens barrel to which a front ring 7 is connected and fixed, and a movable frame movable therein and a lens group held by the fixed frame are respectively L1 and L2 around the optical axis. The photographic lens barrel is configured by being positioned in parallel with L2, L3, and L4. Among the lens groups arranged in this manner, the lens barrel of the present embodiment employs a lens that can adjust the focal point of the image plane by moving and adjusting the lens group L1 in the optical axis direction for each distance. are doing. The lens group L1 is held by a lens barrel 1, and a roller shaft 2 in which a roller 27 is fitted is implanted in the lens barrel 1. The roller 27 penetrates a not-shown rectilinear long hole of the front ring 7 and a not-shown cam-shaped long hole of the lens moving ring 8 fitted to the upper side of the front ring 7. The lens barrel 1 moves along the lens group L1 together with the lens group L1 in accordance with the straight-moving component of the cam-shaped long hole because the rotation direction is blocked by the rectilinear long hole of the front ring 7 on the fixed side while trying to move along the long hole. 7 can be slid. There is a guide ring 11 capable of rotating the lens moving ring 8. The connecting portions 8a and 11a are connected to each other so that the lens moving ring 8 and the guide ring 11 can rotate integrally. Planetary gear 3 on guide ring 11
Is provided, and can rotate around the circumference according to the planetary movement of the planetary gear 3. As shown in the perspective view of the detail view of the planetary gear and the interlocking mechanism of FIG. 3, the planetary gear shaft 4 is erected at a plurality of balanced locations on the guide ring 11, and the upper portion is formed in a screw shape. The upper gear 3a, the lower gear 3b having a different number of teeth from the upper gear 3a, and the friction spring 5 for generating frictional resistance between the two planetary gears are inserted with the two bearing screws 15 as cores. A unit formed by screwing the spring adjusting nut 6 into the unit is inserted into the planetary gear shaft 4, and the unit is stopped at the top of the planetary gear shaft 4 by a holding ring 16 so that the unit does not come off. For this reason, the entire unit rotates around the planetary gear shaft 4, and the upper gear 3a and the lower gear 3b are held together by the friction adjusted by the spring adjusting nut 6 and rotate integrally, but the external force exceeding the mutual frictional force is applied. When they are applied separately, their relative positions can be changed. Next, the vibration wave motor serving as a drive source for the automatic focusing operation is closer to the focal point than the guide ring 11 (right side in the figure).
The motor base tube 13 fitted to the fixed tube 12 is positioned inside, and the flange 13a of the motor base tube 13 is
The disassembled parts as shown in (1) and (2) are sequentially overlapped and fixed between the flange portions 12a of the fixed cylinder 12. A plurality of pressure adjusting screws 28 are set on the circumference of the flange portion 13a of the motor base cylinder 13. A ring-shaped leaf spring 21 is placed from the inside thereof, and a stator holder 24 is placed thereon. The stator 18 is held across a vibration absorber 19 that absorbs the vibration of. A ceramic piezoelectric element 22 is attached to the bottom of the stator 18, and a small vibration distortion is caused by the applied vibration voltage to cause the entire stator 18 to vibrate. As shown in the figure, grooves are formed at regular intervals to form an effective progressive surface wave in which the vibration is effective to obtain rotational drive for the contact surface of the rotor 17, thereby forming a tooth shape. Further, the stator 18 is held by the motor base cylinder 13 and is prevented from rotating by a stator set screw 23 from the side.
8 is stopped. Rotor 1 on vibrating surface of stator 18
A rotational driving force is obtained on the rotor 17 by pressing the rotor 7 against the rotor 7. A sliding member 25 having wear resistance is attached to the rotor 17 to prevent the surface of the stator 18 and the rotor surface from being worn. A holding plate 26 made of a material having no influence on the vibration system of the rotor and having no rotational slip is placed on the rotor 17,
Output ring 2 that takes out the rotation output of the rotor from above
0 is set so that the driving force of the motor can be transmitted to the outside from the gear portion 20a. The output ring 20 is inserted into the groove of the rotating ring 14c and the base 14a by the ball 14b.
Are received by an annular bearing 14 arranged and sandwiched. The annular bearing 14 is attached to the flange 12a of the fixed cylinder 12 through an attachment hole 14d, and the rotor 17 is brought into contact with the annular bearing 14 to form an integral body. As described above, the contact pressure between the rotor 17 and the stator 18 which determines the output characteristics of the vibration wave motor is provided between the fixed portions 12a and 13a of the motor base tube 13 on the fixed side. The adjustment can be arbitrarily performed by a pressure adjusting screw 28 provided on the flange portion 13a of the right motor base cylinder 13. The upper gear 3a of the planetary gear 3 installed on the guide ring 11 meshes with the output gear 20a of the output ring 20 for taking out the rotation output of the motor, and the planetary gear 3
The lower gear 3b meshes with the manual gear 10a of the manual operation ring 10 in which focus adjustment can be manually operated, and an automatic or manual drive system is connected to the planetary gear 3 through the guide ring 11 by both driving forces. It has an adjustable configuration. Next, the operation in such a configuration will be described. First, in the case of the auto-focus operation, the direction to approach the best focus and the high-frequency voltage signal for the rotational drive are applied to the ceramic piezoelectric element 2 according to the defocus amount detection on the camera side.
2 and a traveling wave vibration is generated on the surface of the stator 18 in accordance therewith. In accordance with the direction of the traveling wave, a rotational driving force is generated in the rotor 17 that is in pressure contact with the stator 18. This causes the output ring 20 to rotate while rolling on the rotating ring 14c of the annular bearing 14 on the upper side together with the push plate 26. The planetary gear 3a meshing with the output gear 20a is rotated together with the rotation of the output ring 20, but is rotated integrally with the other planetary gear 3b held by the frictional force.
Since 0 is in a stopped state, the planetary gear 3 moves in the same direction while rolling on the internal teeth of the manual gear 10a with which 3b is engaged. Accordingly, the guide ring 11 rotates, and the lens moving ring 8 can be rotated in conjunction with the rotation. As described above, the lens barrel 1 and the lens unit L1 are moved in parallel with the optical axis, and approach the in-focus position. In this case, the motor output ring 2
Planetary gear 3 meshing with output gear 20a integral with
When the gear ratio of the upper gear 3a with respect to the lower gear 3b is increased, the focus adjustment angle with respect to the motor rotation decreases, and the torque increases. Conversely, when the gear ratio is reduced, the focal adjustment angle with respect to the motor rotation increases, Since the torque is reduced, the gear ratio between the upper gear 3a and the lower gear 3b of the planetary gear 3 can be optimally set according to the characteristics of the vibration wave motor to be mounted. In the case of manual adjustment, when a rotational force greater than the rotation stopping force of the friction ring 30 against the fixed ring 29 is manually applied to the operation ring 10b, the manual operation ring 10 rotates and the upper gear 3a can rotate. , The lower gear 3b meshing with the upper gear 3a is rotated. However, since the motor side is stopped, the planetary gear 3a is also rotated.
, And rolls outward while meshing with the output gear 20a of the motor. Since this also rotates the guide ring 11 in the same manner as the motor operation, the lens group L1 is moved in parallel with the optical axis in accordance with this.
Focus adjustment is manual. In this case, the operation ring 10b receives a load from the friction ring 30 and a load from the lens moving ring 8,
This is adjusted to the feel of manual operation, and the upper gear 3a of the planetary gear 3 is adjusted.
By changing the ratio of the number of teeth of the lower gear 3b to that of the lower gear 3b, an optimum gear ratio can be set. That is, if the ratio of the number of teeth of the lower gear 3b to the upper gear 3a of the planetary gear 3 meshing with the manual gear 10a of the manual operation ring 10 is increased, the focus adjustment angle by manual operation increases, the operation torque decreases, and conversely, the teeth decrease. Reducing the ratio reduces the focus adjustment angle and increases the operating torque. From this, an optimum manual operation feeling can be obtained by appropriately setting the gear ratio of the lower gear 3b and the upper gear 3a according to the type of the lens. In the above description of the automatic operation and the manual operation, the case where one of them is stopped or not operated has been described. However, there is no problem even if the manual operation ring is operated while the motor is operating. For example, when the guide ring 11 is rotated clockwise by the rotation of the motor, when the guide ring is manually operated to rotate in the same direction, when the lens movement is superimposed, the lens is accelerated and moved, and when operated in the opposite direction. Slip acts between the upper gear 3a and the lower gear 3b of both planetary gears held by friction, and the lens moves by the differential of the two gears. On the other hand, the upper gear 3
The slip operation between the planet gears of the lower gear 3a and the lower gear 3b also occurs at the end position beyond the movable range of the lens, and plays a role of releasing extra operating force by this slip. For example, when the operating ring is manually turned beyond the movable range of the lens (from close to infinity), slipping occurs between the two planetary gears, so that no other adverse effects occur. The upper gear 3a and the lower gear 3b
The friction couple between them affects the stopping friction of the operating ring and the operating feeling,
Also, since the relationship between the friction between the stator 18 and the rotor 17 of the motor is large, the present invention is characterized in that the optimum friction adjustment can be performed independently of each other. As described above, the annular vibration wave motor and the automatic and manual differential mechanism systems have independent structures, and the planetary gears of the differential mechanism system adapted to the mechanical characteristics of the lens have teeth. By dividing into two gears of different numbers and meshing with each other, characteristics satisfying the optimum conditions of various lenses can be obtained, and in the manual adjustment of the AF lens, the adjustment can be performed at all times without providing any special switching means. And a highly reliable AF lens barrel can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration sectional view of a lens barrel according to an embodiment. FIG. 2 is an exploded perspective view of the annular vibration wave motor of the embodiment. FIG. 3 is a detailed perspective view of a planetary gear and an interlocking mechanism of the embodiment. [Description of Signs] 1 Lens frame 2 Roller shaft 3 Planetary gear 4 Planetary gear shaft 5 Friction spring 6 Spring adjustment nut 7 Front ring 8 Lens moving ring 10 Manual operation ring 11 Guide ring 12 Fixed cylinder 13 Motor base cylinder 14 Ring bearing 15 Bearing Screw 16 Press Ring 17 Rotor 18 Stator 19 Vibration Absorber 20 Output Ring 21 Leaf Spring 22 Ceramic Piezo Element 23 Stator Set Screw 24 Stator Holder 25 Sliding Material 26 Press Plate 27 Roller 28 Pressure Adjusting Screw L1 Lens Group L2 Lens Group L3 lens group L4 lens group

Claims (1)

Claims: 1. An annular ring comprising a stator held by a spring capable of adjusting a contact pressure between a rotor and a stator, and a rotor connected to a gear held by an annular bearing on a fixed side. The vibration wave motor is provided independently around the optical axis of the lens, and the focus is automatically adjusted by the rotation of the motor and manually operated by the operation of the manually operated ring which is located at the outer ring and is normally stopped by friction with respect to the fixed ring. In a lens barrel that enables focus adjustment, a rotatable guide ring directly connected to a focus adjustment lens moving ring and a planetary gear installed on the ring have two shafts with a common shaft and different numbers of teeth. Are held in pressure contact with each other so as to have frictional resistance with each other, one of the planetary gears is connected to the rotor holding gear of the motor on the inside, and the other of the planetary gears is the teeth of the manually operated ring on the outside. The lens barrel being characterized in that the automatic focusing angle and manual operation can be changed depending on the type of lens manual focus adjustment angle optimum ratio by the structure according to the motor drive by the structure for connecting the parts.