JP3205031B2 - Lens barrel and motor drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel incorporating a motor and a motor driving device.

[0002]

2. Description of the Related Art Conventionally, in a known autofocus camera configured to selectively perform an autofocus operation and a manual focus operation, switching from an autofocus operation to a manual focus operation and a manual focus operation are performed. When the camera user attempts to switch to the autofocus operation, it is necessary to operate a switching operation member provided outside the camera.

[0003]

However, in the above-mentioned conventional example, when the automatic focusing mode is selected at the time of photographing, when the automatic focusing becomes impossible, or when it is desired to perform fine adjustment after the automatic focusing, the external operation member is required. It is necessary to switch to the manual focusing mode and perform the manual focusing operation by the above operation, and there is a disadvantage that the quick shooting performance is poor and a shooting opportunity is missed.

On the other hand, when an annular ultrasonic motor is used for a lens barrel as a drive source for autofocus, a rotational output can be directly applied to a focus lens without using a transmission mechanism such as a gear. It has been proposed to provide a differential mechanism between a focus lens and a motor in order to enable automatic driving and manual driving without performing any switching operation.

[0005] However, the annular type ultrasonic motor is disadvantageous in terms of manufacturing cost, and therefore, a type using a rod-shaped ultrasonic motor as a drive source for autofocus has been proposed.

Since the rod-shaped ultrasonic motor cannot be disposed so as to surround the lens like an annular ultrasonic motor, the rotational force of the output member is transmitted to the focus lens via the transmission mechanism. For such a lens barrel equipped with a rod-shaped ultrasonic motor, there has not been proposed any method capable of switching between auto-focusing and manual focusing without switching by the above-mentioned external operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens barrel capable of switching between auto and manual focus without operation by using a rod-shaped ultrasonic motor or the like as a drive source, and a motor drive device suitable for driving the lens barrel. is there.

[0008]

According to a first aspect of the present invention, there is provided a first gear for transmitting a torque from a motor, a second gear for transmitting a torque from a manual operating means, the first gear and the second gear. A plurality of rotating members sandwiched by gears, a third gear that supports the rotating members and is connected to the driven member, and the first gear, the second gear, and the third gear are coaxially arranged and geared. Having a pressurizing member for pressurizing the first gear and the second gear via the rotating member, by rotating the first gear or the second gear with the motor or the manual operation means. Driving the driven member by revolving the rotating member about the rotation center of the first gear, the second gear, and the third gear, and rotating the third gear following the rotation center. It is in the characteristic lens barrel. In a second aspect based on the first aspect, the motor is a rod-shaped ultrasonic motor driven to rotate by a frictional force between a stator and a rotor, and the first gear is driven to rotate by an output of the rod-shaped ultrasonic motor. When the second gear is rotated by the manual operation means, the frictional resistance of the manual operation means is determined so that the second gear does not rotate. The first gear is configured not to rotate due to frictional resistance between the stator and the rotor. In a third aspect based on the first aspect, the driven member is a member for moving the focus lens in the optical axis direction. According to a fourth aspect of the present invention, there is provided a first gear transmitting torque from a motor, a second gear transmitting torque from manual operation means, and a plurality of rotating members sandwiched by the first gear and the second gear. And a third gear that supports the rotating member and is connected to the driven member, and the first gear, the second gear, and the third gear are arranged coaxially, and the first gear and the second gear are A pressurizing member that pressurizes via the rotating member, and the first gear or the second gear is rotated by rotating the first gear or the second gear with the motor or the manual operation means. 2. The motor drive device according to claim 1, wherein the third gear is revolved with respect to the rotation center of the third gear and the third gear is driven to rotate with respect to the rotation center to drive the driven member.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 is a sectional view of a gear unit for transmitting the output of a rod-shaped ultrasonic motor. In the figure, B is a rod-shaped ultrasonic motor, and its internal structure will be described.

Reference numeral 51 denotes a cylindrical vibration elastic body made of a metal material; 52, a presser body made of a metal material having the same outer diameter as that of the vibration elastic body 51; An annular piezoelectric element plate having an outer diameter equal to the diameter is formed, and 54a to 54d are electrode plates of the piezoelectric element plates 53a to 53d. Plates 54a to 54d and piezoelectric element plates 53a to 53d are disposed, and a vibration elastic body 51 is
Are fixed together by screwing to the stator (vibrator) of the ultrasonic motor B.

The ultrasonic motor B is connected to the electrode plate 5 of the stator.
By applying AC voltages having different phases from a power supply circuit (not shown) to the piezoelectric element plates 53a to 53d.
Generates mechanical vibrations in the stator, and the combination of these vibrations excites a rope-like movement in the stator to frictionally drive the rotor 56 described below, which comes into frictional contact with the front end of the stator. 56 is a rotor, a rear end portion (friction contact portion)
a is brought into contact with the flat portion 51a of the vibration elastic body 51, and an appropriate frictional force is obtained by applying pressure by a pressure spring 60 described later.

Reference numeral 57 denotes a rotation output member having a gear 57a, which is integrated with the rotor 56. This gear 5
7a is for transmitting the rotation of the rotor 56 to the outside.

A bearing 58 is provided on the inner diameter of the rotation output member 57, and a hollow shaft 59 is fitted into the inner diameter of the bearing 58, so that the rotor 56 and the rotation output member 57 can rotate.

The shaft 59 is fitted to the sliding portion 55a of the bolt 55 so as to coincide with the axis of the stator. 60
Is a pressure spring, which presses a step portion 59a of the shaft 59 to press a bearing 58 by a flange portion 59b.
The pressing force generates a frictional force between the vibration elastic body 51 and the rotor 56.

The pressing force of the pressure spring 60 is applied by a well-known method such as inserting the hole 61a of the flat holding member 61 into the pin 55b formed at the tip of the bolt 55, and fixing it with, for example, an adhesive. It is generated by fixing.
The above is the configuration of the ultrasonic motor B.

The ultrasonic motor B is fixed by fixing the holding member 61 to a motor base plate 72 as a fixing member with screws 14 and 15. When supporting the stator of the ultrasonic motor, it is necessary not to affect the vibration excited by the stator, and the end of the stator becomes the antinode position of the vibration, and there is only displacement in the radial direction. Moreover, since the displacement is actually very small, fixing the pin portion 55b, which is one end of the stator, does not affect the vibration of the stator.

The frictional force of the frictional connection between the rotation output member 57 and the rotor 56 is generated by the pressure spring 60, and the force is smaller than the frictional force between the vibrating elastic body 51 and the rotor 56 (the friction coefficient becomes smaller). So) is set.

That is, even when a rotational force is applied to the rotation output member 57 from the outside, the rotor 56 does not rotate because the friction force on the stator is larger than the friction force on the output member 57, and only the rotation output member 57 is rotated. Will rotate.

In FIG. 1, reference numeral 76 denotes a gear for transmitting the rotation of the rotation output member 57 to an AF driving gear 77, reference numeral 77 denotes an AF driving gear for transmitting rotation from the gear 76 to a ball member 79 as a rotating member, and reference numeral 78 denotes a gear. A gear that transmits the rotation from the manual operation means to the ball member 79 by transmitting the rotation from the gear 83 to the gear 84. The gear 79 is sandwiched between the gear 77 and the gear 78, and the rotational force of the gear 77 and the gear 78 is frictional force with the gear 77. , A ball member that rolls around a gear shaft 82 by frictional force with the gear 78 to rotate the gear 81 in a driven manner, and 80 is a pressurizing member, and is a pressing member with the gear 77 and the ball member 79, and the gear 78 and the ball member 79. A friction force is generated between them. 81 has the ball member 79 in a hole on the circumference and is driven and rotated by the rolling revolution of the ball member 79;
Gear 86 → gear 87 → gear transmitting to lens moving means,
Reference numeral 82 denotes a gear shaft for coaxially disposing the gear 77, the gear 78, and the gear 81. The gear 77, the gear 78, and the gear 81 are fitted to each other and can rotate freely. The gear 83 is fixed to a fixed shaft of the gear 84, and transmits rotation from manual operation means. The gear 87, like the gear 83, is fixed to a fixed shaft of the gear 86, and transmits the rotation from the gear 81 to the lens moving means.

Next, in FIG. 2, reference numeral 85 denotes a manually operated cylinder, and the manually operated cylinder 8 is used for manual driving.
The gear 83 meshes with a gear portion 85 a provided on the fifth gear 5. Reference numeral 88 denotes a rotary cylinder, and the gear 87 meshes with a gear portion 88b provided for output driving, and rotates at a fixed position. Further, the rotation angle is regulated by the stopper key 91. Further, a helicoid screw portion 89a of a rectilinear barrel 89 having a lens L and performing focus zoom is helicoidally coupled to the helicoid screw portion 88a provided with the rotary cylinder 88. A rectilinear key 92 for inhibiting rotation is fitted in the rectilinear cylinder 89. Reference numeral 90 denotes a fixed cylinder to which the motor base plate 72 and the straight key 92 are fixed.

Hereinafter, the movements of the motor driving device and the lens barrel will be described in detail.

First, at the time of automatic focusing, when a lens drive signal is received by a drive circuit (not shown) provided in a camera (not shown), an AC voltage is applied to the electrode plates 54a to 54d of the motor B. That is, as described above, the rotor 5
6 rotates in a predetermined direction (the rotation direction is performed by reversing the phase advance of two applied AC voltages having different phases, for example). Due to the rotation of the rotor 56, the rotation output member 5 frictionally coupled to the rotor 56
7 also rotates, and its rotation output is transmitted from gear 76 to gear 77. At this time, the frictional resistance at the contact portion 77a between the gear 77 and the gear shaft 82 is set to be smaller than the frictional resistance of the rotary cylinder 88. The ball member 79 is sandwiched between the gears 77 and 78, and the pressing member 8
Since it is pressurized by 0, a frictional force acts between the gear 77 and the ball member 79 and between the ball member 79 and the gear 78. Here, the manually operated cylinder 85 that is linked with the gear 78 has a frictional resistance greater than the frictional resistance between the gear 78 and the ball member 79. Does not rotate. Therefore, the gear 78 does not rotate, and the rotation of the gear 77
The gear 81 is driven to rotate by the ball member 79 rolling around the gear shaft and revolving. Then, the rotation of gear 81 → gear 86 → gear 87 is output. The rotation output from the gear 87 causes the rotary cylinder 88 to rotate in a fixed position, and the rectilinear cylinder 89, which is helicoidally coupled to the rotary cylinder 88, is guided by the rectilinear key 92 to advance straight, and an automatic focusing operation is performed. . In this case, the straight key 92
Are fixed to the fixed cylinder 90 with screws 94.

On the other hand, during manual focusing, when a rotational force is applied to the manual operation cylinder 85 from the outside, the manual operation cylinder 85 is rotated by the gear 83 meshing with the gear portion 85a of the manual operation cylinder 85, and the gear 84 → It is transmitted to the gear 78. Then, contrary to the case of automatic focusing, since the frictional resistance between the rotor and the stator of the ultrasonic motor B is larger than the frictional resistance between the gear 77 and the ball member 79, the gear 77 does not rotate. The rotation of the gear 78 is transmitted to the ball member 79 by the frictional force between the ball member 79 and the ball member 79, and the ball member 79 rolls and revolves around the gear shaft, so that the gear 81 is rotated.
Is driven to rotate. Then, similarly to the case of the automatic focusing, the transmission is performed from the gear 86 to the gear 87, the rotating cylinder 88 rotates at a fixed position, the rectilinear cylinder 89 moves straight, and the manual focusing operation is performed.

In this embodiment, the gear 77 and the gear 81 are used.
And the rotation ratio between the gear 78 and the gear 81 are designed to be 2: 1.

[0026]

According to the present invention, three gears are arranged coaxially and a plurality of rotating members are arranged in the middle gear, so that switching between the motor drive and the manual drive of a driven member such as a focus lens can be performed. This can be performed without the need to operate the automatic-manual switching operation member. Particularly when a rod-shaped ultrasonic motor is used as the motor, the configuration for switching between motor driving and manual driving can be simplified, and the lens mirror can be used. The size of the cylinder can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a motor unit showing an embodiment of the present invention.

FIG. 2 is a sectional view of a lens barrel incorporating the motor unit of FIG. 1;

[Explanation of symbols]

 B: Bar-shaped ultrasonic motor 51: Vibration elastic body (stator) 53: Piezoelectric element plate 56: Rotor 57: Rotary output member 60: Pressurizing spring 65 to 67: Gears 76, 77, 78: Gear 79: Ball member 81: Gears 83, 84, 86, 87 Gear 85 Manual operation cylinder 88 Rotary cylinder

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-182709 (JP, A) JP-A-1-124808 (JP, A) JP-A-2-253214 (JP, A) JP-A-63-1988 311221 (JP, A) JP-A-63-226610 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B ^7/ 04-7/ ¹⁰

Claims (4)

(57) [Claims] A first gear transmitting torque from a motor; a second gear transmitting torque from a manual operating means; and a plurality of rotating members sandwiched by the first gear and the second gear. a third gear that is connected to the driven member to support the said rotary member, said first gear, Ru is arranged a second gear, a third gear coaxially
And a pressurizing member for pressurizing the first gear and the second gear via the rotating member, wherein the motor or the manual operating means rotates the first gear or the second gear. Thereby, the rotating member is moved with respect to the rotation center of the first gear, the second gear, and the third gear.
A lens barrel of the third gear by revolving was characterized by is driven to rotate with respect to the rotation center, to drive the driven member Te. 2. The motor according to claim 1 , wherein the motor is a rod-shaped ultrasonic motor driven to rotate by a frictional force between a stator and a rotor, and the first gear is driven to rotate by an output of the rod-shaped ultrasonic motor. The frictional resistance of the manual operation means is determined so that the second gear does not rotate, and when the second gear is rotated by the manual operation means, the stator and the rotor of the rod-shaped ultrasonic motor are rotated. A lens barrel characterized in that the first gear does not rotate due to frictional resistance therebetween. 3. The driving member controls a focus lens to emit light.
It is a member for moving in the axial direction
The lens barrel according to claim 1. 4. A first gear for transmitting torque from a motor.
Ya and, a second gear for transmitting rotational force from a manual operation means, said first gear, a plurality of rotating portions sandwiched by the second gear
Material and supports the rotating member and is connected to the driven member
A third gear and the first gear, the second gear, and the third gear are coaxially arranged.
In addition, the first gear and the second gear are connected to the rotating member.
And a pressurizing member for pressurizing through the first gear or the manual operation means by the motor or the manual operation means.
Rotates the second gear so that the rotating portion
Material with respect to the rotation center of the first gear, the second gear and the third gear
Revolve and rotate the third gear with respect to the rotation center.
And driving the driven member.
Motor drive.