JPH05263879A - Driving force transmitter and lens mirror cylinder - Google Patents

Abstract

PURPOSE:To provide a driving force transmitter which can switch an input without performing any special operation and is suitable to employ an ultrasonic motor as a system of input by having two systems as input and one system as output. CONSTITUTION:A gear 17 gear-connected to a ultrasonic motor A side and a gear 21 meshed with a gear 35 are set as an input side and a retainer gear is set as an output side. A ball member 22 which is fit in a V-shaped groove formed by the inner circumferencial face of the gear 17 and an outer member 18 pressurized in the axial direction, is set so as to be pressed against the circumferencial face of the gear 21 by elastic force of a pressure member 19. And the gear 21 is brought in frictional contact with a shaft 16 by means of a friction spring 24. This frictional force is set larger than the frictional force with the ball member 22 pressed by the gear 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive force transmission mechanism having one output section for two input sections, and for two input sections such as autofocus and manual focus in a camera or the like. The focus lens (driven member) can be operated substantially continuously without any special switching operation, and a driving force transmission device and lens barrel particularly suitable for using a rod-shaped ultrasonic motor as a drive source It is about.

[0002]

2. Description of the Related Art Conventionally, for example, in a camera that can selectively perform an autofocus operation and a manual focus operation, switching from the autofocus operation to the manual focus operation or from the manual focus operation to the autofocus operation is performed. When the user of the camera intends to perform the above switching, it is necessary to operate a switching operation member provided outside the camera, for example, outside the lens barrel.

[0003]

However, in the above-described conventional example, for example, at the time of photographing, the camera user first selects the autofocus operation, and after tracking the subject, the manual focus operation is continuously performed after the autofocus operation. When attempting to do so, the camera user must rotate the manual operation member of the lens barrel of the camera after operating the switching member, which delays the start of the manual focus operation, resulting in a shooting opportunity. It had the drawback of missing it.

The object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to drive a driven member such as a focus lens substantially continuously without requiring a special switching operation for two systems of inputs. It is to provide a driving force transmission device and a lens barrel.

[0005]

The specific structures of the driving force transmission device and the lens barrel that achieve the object of the present invention are as set forth in the claims.

[0006]

1 is a sectional view showing a first embodiment of a driving force transmission device according to the present invention. 2 shows an embodiment in which the device of FIG. 1 is applied to a lens barrel.

Reference numeral 1 denotes a cylindrical vibrating elastic body made of a metallic material, 2 denotes a pressing body made of a metallic material having an outer diameter of the same shape as that of the vibrating elastic body 1, and 3a to 3d denote outer diameters of the vibrating elastic body 1. An annular piezoelectric element plate 4a having the same outer diameter as that of
4d are electrode plates of the piezoelectric element plates 3a to 3d, and the electrode plates 4a to 4d and the piezoelectric element plates 3a to 3d are arranged between the vibrating elastic body 1 and the pressing body 2, and the bolt 5 is pressed down. The stator (vibrator) of the ultrasonic motor A is configured by screwing the vibration elastic body 1 through the body 2 and fixing them integrally.

The ultrasonic motor A has a stator electrode plate 4a.
The piezoelectric element plates 3a to 3d form mechanical vibrations in the stator by applying alternating voltages having different phases to the stators 4d to 4d. The rotor 6 (described later) that excites the motion and makes frictional contact with the front end portion of the stator is frictionally driven. A rotor 6 has a rear end portion (friction contact portion) 6a abutting against the driving surface 1a of the vibrating elastic body 1 and obtains an appropriate frictional force by pressurization by a pressure spring 10 described later.

Reference numeral 7 is a rotation output member having a gear portion 7a,
The rotor 6 is coupled so as to rotate integrally therewith, and the rotation of the rotor 6 is transmitted to the outside.

A bearing 8 is provided in the inner diameter portion of the rotation output member 7, and a hollow shaft 9 is fitted in the inner diameter portion of the bearing 8 so that the rotor 6 and the rotation output member 7 can rotate.

The shaft 9 is fitted to a holding member 11 which will be described later so as to be aligned with the shaft center of the stator. Reference numeral 10 denotes a pressure spring, which presses the step portion 9a of the shaft 9 to press the bearing 8 by the flange portion 9b, and the pressing force causes a frictional force between the vibrating elastic body 1 and the rotor 6. Is configured.

The pressing force of the pressure spring 10 is fixed by inserting the pin portion 5a formed at the tip of the bolt 5 into the hole portion 11a of the flat plate-shaped holding member 11 and fixing it with an adhesive, for example. It is caused by that. The above is the configuration of the ultrasonic motor A.

This ultrasonic motor A has the above-mentioned holding member 1
1 is fixed to a metal base plate 14 described later by screwing with screws 12. When supporting the stator of the ultrasonic motor, it is necessary not to affect the vibration excited in the stator. The end of the stator is the antinode position of the vibration, and there is only a radial displacement. Moreover, since the displacement is actually very small, fixing it with the holding member 11 which is one end of the stator does not affect the vibration of the stator.

A gear base plate 13 is integrally formed with a gear shaft, a bearing and the like by molding. Reference numeral 14 denotes a metal base plate which fixes the ultrasonic motor A and holds each gear with the gear base plate 13. Reference numeral 15 is a connecting gear that transmits the rotation of the rotation output member 7 to the gear 17. 16 is a gear shaft,
Reference numeral 17 denotes a tapered surface 17 that contacts the ball member 22 on the inner circumference.
a is a gear that receives rotation from the gear 15, and 18 is an outer member for radially pressing and sandwiching between the gear 17 and the gear 21 by the inner peripheral tapered surface 18a via the ball member 22, Reference numeral 19 denotes a pressing member, which generates a frictional force between the outer member 18 and the gear 17, the ball member 22, and the gear 21 and the ball member. The pressure member 19 also applies pressure in the axial direction so that the outer member 18 and the gear 17 rotate integrally. 20 is an outer member 18,
This is a cap for integrally forming the gear 17 and the pressing member 19.

Reference numeral 21 denotes a gear that rotates in response to the rotation of the gear 35. Reference numeral 22 denotes a shaft portion 21b of the gear 21 and the outer member 18.
And the gear 17 presses it radially, and the shaft portion 21b
This is a ball member that rotates the retainer gear 23 in a driven manner by rotating around the gear shaft 16 by a frictional force, and at least three ball members 22 are concentrically arranged. 23 is the gear shaft 16 of the ball member 22.
The ball member 22 so as to transmit only the rotation about the
Is a retainer gear, and 24 is a friction spring that generates a frictional force between the gear shaft 16 and the gear 21. 25, 26, 27 are washers, and the washer 26
Is the friction spring 24, and the washer 27 is 17-
The members up to 23 are fixed in the axial direction. The driving force transmission mechanism unit B is constructed in this manner, and is fixed to the gear base plate 13 by the screw 28. Reference numerals 29 and 30 are gears that form an output member for transmitting rotation to a rotary cylinder 39, which will be described later, and reference numerals 31 and 32 are gears that transmit rotation to the pulse plate 33. A pulse plate 33 is fixed to the gear 32 and rotates integrally with the gear 32. 34 is an interrupter,
It is fixed to the interrupter fixing portion 13a of the gear base plate 13 and transmits a signal from the pulse plate to a lens drive control circuit (not shown). Reference numerals 35 and 36 denote input members, for example, gears that transmit the rotation of the manual operation member 41 to the gear 21, and 37 denotes screws for fixing the gear base plate 13 and the metal base plate 14.

Between the gear base plate 13 and the metal base plate 14, around the gear shaft 16, a gear 17, an outer member 18, a pressure member 19, a cap 20, a gear 21, a ball member 22, a retainer gear 23, and a friction spring 24. Are assembled into a unit. Therefore, variations in the rotational force of the retainer gear 23, which is an output member, can be managed in a unit state.

Next, in FIG. 2, reference numeral 39 denotes a rotary cylinder, which is adapted to rotate in a fixed position by meshing the gear 30 with a gear portion 39a provided for output driving, and a rotation angle by a stopper key 42. It is regulated. Further, the helicoid screw portion 40a of the rectilinear barrel 40 having the lens L is helicoidally coupled to the helicoid screw 39b provided on the rotary barrel 39. A straight key 43 for inhibiting rotation is fitted into the straight barrel 40. 41
Is a manual operation member, and the gear 36 meshes with a gear portion 41a provided on the manual operation member 41 for a manual focusing operation. Reference numeral 46 is a fixed cylinder, which includes a metal base plate 14 and a stopper key 4.
2. The straight key 43 is fixed with screws 38, 44 and 45, respectively.

The movements of the driving force transmission device and the lens barrel will be described in detail below with reference to FIGS.

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 4a-4d of the motor A, and As described above, the rotor 6 rotates in a predetermined direction.
This is done by reversing the phase lead of one AC voltage. ). Due to the rotation of the rotor 6, the rotation output member 7 coupled so as to rotate integrally with the rotor 6 also rotates, and the rotation is transmitted to the gear 17 by connecting the gear 15 and the gear 15. The assembled outer member 18 also rotates. At this time, a frictional force acts between the outer member 18 and the gear 17 and the ball member 22 due to the pressure of the pressure member 19.

A frictional force is generated between the gear 21 and the gear shaft 16 by the friction spring 24, which is a holding force larger than the frictional force between the shaft portion 21b of the gear 21 and the ball member 22. Therefore, the gear 21 does not rotate during the automatic focusing operation. Therefore, the rotation of the gear 17 and the outer member 18 causes the ball member 22 to move to the gear 21.
Since it rotates around the shaft portion 21b of the rotary shaft 21b about the gear shaft 16, the retainer gear 23 is driven to rotate by this, and the rotation is transmitted to the gear 29 and the gear 30. The straight-moving barrel 40, which is rotated by a value and is helicoidally coupled to the rotary barrel 39, is the straight-forward key 4.
The vehicle is guided by 3 and goes straight, and the automatic focusing operation is performed.

On the other hand, during the manual focusing operation, when a rotational force is applied to the manual operation member 41 from the outside, the manual operation member 4
The gear 36 meshing with the first gear portion 41a rotates, and in conjunction with this, the gear 35 and the gear 21 also rotate. At this time, between the shaft portion 21b of the gear 21 and the ball member 22,
Friction is exerted by the pressurization of the pressure member 19. Here, contrary to the case of automatic focusing, the frictional force between the rotor 6 and the stator 1 of the ultrasonic motor A is now greater than the frictional force between the gear 17 and the outer member 18 and the ball member 22. Since it is large, the gear 17 and the outer member 18 do not rotate.

Accordingly, the rotation of the gear 21 causes the ball member 22 to rotate around the shaft portion 21b of the gear 21 while rolling around the gear shaft 16, and the retainer gear 23 is driven to rotate similarly to the case of automatic focusing. , Gear 29 → gear 30
The rotary barrel 39 and the straight barrel 40 are operated to perform the manual focusing operation.

FIG. 3 is a sectional view showing the second embodiment.

The difference from the above-described first embodiment shown in FIG. 1 is a part of the driving force transmission mechanism B, and therefore the other parts are denoted by the same reference numerals and the description thereof will be omitted. Let C be the driving force transmission mechanism.

In FIG. 3, reference numeral 101 denotes a gear integrated with a shaft, which is fitted in the hole of the gear base plate 13 and the hole of the metal base plate 14 and is rotatable. Reference numeral 102 is a gear pressure member made of silicone rubber, and 103 is a friction sheet. A friction force is applied to the gear 101 by the gear pressure member 102 and the friction sheet 103, and the force is applied to the shaft portion 101a of the gear 101 and the ball member 2.
Since the holding force is larger than the frictional force between the gear 101 and the gear 2, the gear 101 does not rotate during the automatic focusing operation (the gear 17 rotates).

Next, the operation will be described. First, at the time of automatic focusing, the gear 17 is rotated by the rotation of the rotation output member 7 of the motor A as in the first embodiment, the rotation is transmitted to the ball member 22 → the retainer gear 23, and the gear 29 → gear 30 →
Rotation is transmitted to the lens drive mechanism and automatic focusing is performed. At this time, in this embodiment, as described above,
The gear 101 is held so as not to rotate.

Next, during manual focusing, when the manual operation member is rotated as in the first embodiment, the rotation is transmitted from the gear 36 to the gear 35 and the gear 101 is rotated. Then, the ball member 22 revolves around the peripheral surface of the portion 101a of the gear 101 while rotating, and the rotation is transmitted to the retainer gear and output. At that time, a suitable weight is added by the friction force of the gear pressure member 102 and the friction sheet 103, which applied the holding force to the gear 101 during automatic focusing, and the manual feeling is also good.

FIG. 4 is a sectional view showing the third embodiment.

The first embodiment shown in FIG. 1 and the second embodiment shown in FIG.
The difference from the embodiment is the part of the driving force transmission mechanism D in FIG. 4, so the other parts are denoted by the same reference numerals, and the description thereof will be omitted.

Reference numeral 101 denotes a gear integrated with a shaft, which has a taper portion 201a for pressing the ball member 22, and is fitted in the hole portion of the gear base plate 13 and the hole portion of the metal base plate 14. , Can be rotated. 202 is a gear, 2
03 is pressed by the pressing member 19, presses the ball member 22 with the taper portion of the peripheral surface thereof, and presses the gear 202 in the radial direction with the gear 201 via the ball member 22. Further, the pressing member 203 is adapted to rotate integrally with the gear 201 due to the frictional force between the pressing member 203 and the pressing member 19. 204 is a washer for fixing the pressing member 19 in the axial direction.

In this embodiment, the V-shaped groove of the first embodiment is provided on the outer peripheral side of the ball member 22, and, contrary to the case where the ball member 22 is sandwiched under pressure, the V-shaped groove is provided on the shaft side and the inner peripheral surface of the ball member 22 is sandwiched. The operation is similar to that of the first embodiment because it is of a type in which pressure is applied from the side.

[0032]

As described above, according to the present invention, the rotation output member can be switched by switching between, for example, an input from a motor and two external inputs such as a manual operation without any special switching operation. Can be transmitted to.

Particularly, since the first external input member, the second external input member, the rotation output member and the like are coaxially unitized,
It can be easily installed in any mechanical sequence (gear train).

By incorporating the lens barrel,
If you want to perform the manual focus operation immediately after the automatic focus operation, simply rotate the manual operation member without any other operation (automatic means switching as in conventional cameras). Since it is possible to switch from the automatic focusing operation to the manual focusing operation without having to operate the operation member), it is possible to take a photograph intended by the photographer without missing a photo opportunity.

Further, the shaft input member is frictionally rotated by the rotation of the external input member, and the rotational force thereof varies individually. However, since the friction force for preventing the frictional rotation can be managed in the unit state, The friction force can be adjusted, and the adjustment is easy and the variation in friction torque can be reduced. Further, the manual operation member side does not need to be provided with a friction structure for particularly preventing rotation.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a driving force transmission device according to the present invention.

2 is a cross-sectional view showing a state in which the device of FIG. 1 is incorporated in a lens barrel.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

A ... Ultrasonic motor B ... Driving force transmission mechanism unit 1 ... Elastic vibrating body 2 ... Rotor 16 ... Gear shaft 17 ... Gear 18 ... Outer member 19 ... Pressing member 20 ... Cap 22 ... Ball member 23 ... Retainer gear 24 ... Friction Spring 39 ... Rotating cylinder 40 ... Straight advance cylinder 41 ... Manual operation member 43 ... Straight advance key 46 ... Fixed cylinder

Claims (6)

[Claims] 1. A first external input member, which has a ball member contact surface on its peripheral surface and rotates by transmitting rotation from the outside,
At least three ball members arranged so as to abut the ball member abutting surface of the first external input member, and a taper surface facing the ball member abutting surface and abutting the ball member, A second external input member that is arranged coaxially with the first external input member and is rotatable, and a second external input member that is axially movable with respect to the second external input member, and a taper of the second external input member. A pressing member having a tapered surface that forms a V-shaped circumferential groove with the surface and is in contact with the ball member; and a ball member of the first external input member by axially pressing the pressing member. A pressure member for pressing against the contact surface, and the first external input to which the revolution force that revolves while the ball member rotates and contacts the ball member contact surface of the first external input member is transmitted. A rotation output member arranged coaxially with the member, Each of the first external input member and the second external input member has a rotation prevention holding means for preventing friction rotation of the other through the ball member when one is driven. A driving force transmission device characterized by: 2. The driving force transmission device according to claim 1, wherein the first external input member and the second external input member are transmitted with rotational force by transmission means on separate shafts. 3. The driving force transmission according to claim 1, wherein the first external input member, the second external input member, the pressing member, the pressing member and the rotation output member are unitized. apparatus. 4. The source of the rotational force transmitted to the first external input member or the second external input member according to claim 1, 2, or 3, is a rod-shaped ultrasonic motor that also serves as rotation prevention holding means. A driving force transmission device characterized by the above. 5. The method according to claim 1, 2, 3 or 4,
The rotation preventing member of any one of the external input member and the second external input member of claim 1 generates a frictional force by pressing the external input member against a friction surface by a spring member. 6. The rotation output member of the driving force transmission device according to claim 1, 2, 3, 4 or 5, is connected to a lens moving means, and is either a first external input member or a second external input member. Is connected to a manual operation member for moving the lens by manual operation, and the other one of the first external input member and the second external input member is connected to a motor.