JP2000028891A - Lens barrel - Google Patents

Abstract

(57) [Summary] [Object] To provide a lens barrel capable of driving an auto-focus mechanism and a manual focus mechanism without switching operation and providing a variable reduction ratio to drive from a motor. . [Structure] The step gear is a manual focus operation ring 2.
The large gear 12 interlocked with the inner gear portion 2a, the small gear 13 interlocked with the inner gear portion 11a of the focus connecting ring 11, the large gear 12 and the gear shaft 14 inserted in a rotatable state, The gear 12 includes a gear pressure spring 15 of a helical spring for pressing the small gear 13, and a spring retainer 16 press-fitted onto the gear shaft 14 to press the pressure spring 15, and is provided on the output ring 18. It is inserted into a rotating shaft 7 parallel to the shaft in a state where it can be easily rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lens barrel having a vibration wave motor, and more particularly, to a lens barrel having a transmission mechanism for driving a focus lens without switching between auto-focus driving and manual focusing driving. Things.

[0002]

2. Description of the Related Art Conventionally, a transmission mechanism for driving a focus lens without switching between auto focus drive and manual focus drive of a lens barrel having a vibration wave motor has been disclosed in Japanese Patent Application Laid-Open Nos. 2-253214 and 2-253214. Japanese Patent Application Laid-Open No. 2-253217 discloses a method of operating an autofocus mechanism and a manual focus mechanism without switching, with a rotation about a rotation axis in a radial direction orthogonal to an optical axis fixed to a focus lens moving ring. A roller capable of driving the vibration wave motor, and pressing the roller in a direction of the optical axis between the rotor and the manual focus operation ring. Even if driven, the roller is rotated to move the focus lens Transmission mechanism for actuating is disclosed.

Further, Japanese Patent Application Laid-Open No. Hei 2-253210 discloses that
By rolling a large number of freely rolling spherical rolling elements around a rotating ring member that rotates the focus lens moving ring between a rotor that is a driving unit of the vibration wave motor and a manual focus operation ring, A transmission mechanism that rotates the roller to operate the focus lens moving ring regardless of whether the rotor or the manual focus operation ring is driven is disclosed.

[0004] The transmission mechanism in which the rotor of the vibration wave motor drives the focus lens moving ring via a roller or a spherical rolling element as described above employs a manual focus operation ring when the focus lens moving ring is driven by the vibration wave motor. Since the roller or the spherical rolling element rotates in the circumferential direction, the reduction ratio between the rotor or the spherical rolling element and the focus lens moving ring is basically 2: 1.

[0005]

Problems to be Solved by the Invention
No. 4 and JP-A-2-253217 disclose a rotor and a manual focus operation ring using a stepped roller as a roller pressed and held by the rotor and the manual focus operation ring. The reduction ratio can be changed by holding the pressure contact part with a diameter difference and pressing and holding, but if the reduction ratio is to be increased, the diameter difference of the stepped roller must be widened, and as a result, the roller The size of the mechanism must be increased.

[0006] In the transmission mechanism disclosed in Japanese Patent Application Laid-Open No. 2-253210, since the spherical rolling element is pressed and held between the rotor and the manual focus operation ring, the reduction ratio cannot be changed.

As described above, in the transmission mechanism for driving the focus lens moving ring without switching between the auto focus drive and the manual focus drive of the lens barrel having the vibration wave motor, the vibration wave motor and the focus lens movement It was difficult to increase the reduction ratio with the ring, and the driving torque of the vibration wave motor was insufficient for a lens barrel with a large moving distance of the focus lens moving ring or a heavy lens barrel with a moving focus lens moving ring. Could not be remedied in case.

In order to solve this problem, a rotary shaft orthogonal to the optical axis is fixed to the rotor of the vibration wave motor, and a rotation transmission member with a gear that rotates about the rotary shaft is manually provided by the present applicant. A lens barrel (Japanese Patent Application No. 8-33311) having an interlocking portion that makes pressure contact with the operation ring and interlocks the rotation transmission member with gear and the focus lens moving ring.
4) has been filed.

However, this lens barrel (Japanese Patent Application No. 8-33)
In the configuration of 3114), when the user rotates the manual operation ring to a position beyond the operation range, a gap between the roller portion of the rotation transmission member with gear and the surface on which the roller portion of the manual operation ring rolls is provided. It is necessary to set the friction so that the rotation is not transmitted to the vibration wave motor by sliding.

In order to properly set the friction, the material of the surface on which the roller portion of the rotation transmission member with gears and the roller portion of the manual operation ring roll tends to be limited due to the friction coefficient, hardness and the like. In a typical lens configuration, the diameter of the friction surface of the manual focus operation ring was about φ50 to φ70, and a large area of a highly accurate surface required for rolling was necessary, which was expensive in terms of materials and processing.

Further, the rolling surface is normally exposed only when the roller portion of the rotation transmission member with gears passes because it is rolled or frictionally slid, so that dirt and the like easily adhere to the rolling surface. Had become.

This lens barrel (Japanese Patent Application No. 8-33311)
4) When dust or the like enters between the roller portion of the geared rotation transmitting member and the surface of the manual operation ring on which the roller portion rolls, the operation is caught, and in some cases, the rolling surface is bitten. Will happen.

[0013]

In order to solve the above-mentioned problems, a lens barrel according to the present invention comprises a driving member (output ring) having a fixed rotation axis parallel to the optical axis of the lens barrel; A step gear having two different numbers of teeth rotating about an axis, a focus lens moving ring and a manual operation ring rotatable about the optical axis, and the step lens is provided on the focus lens moving ring and the manual operation ring. A configuration is provided in which an interlocking section for interlocking the gears is provided.

With the above configuration, the purpose of driving the focus lens moving ring without switching between auto focus driving and manual focus driving and the reduction ratio of the vibration wave motor to the driving of the focus lens moving ring. In addition to the purpose of making it possible to change the gear, the two different teeth of the stepped gear are pressed against each other by an elastic member such as a spring, and the friction is provided, so that the friction surface is limited to the gear and the end face of the gear, so that a wide A structure that does not require a high-precision surface, does not easily adhere dust to the friction surface, and can easily adjust friction by a spring can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the lens barrel of the present invention, when a focus lens is moved by a vibration wave motor, a driving operation is first performed by a user by operating a focus operation switch, and a vibration circuit is operated by a control circuit. Rotor and output ring rotate about the optical axis.

Thus, a large gear of a stepped gear having two different numbers of teeth, which is fixed to the output ring and rotates about a rotation axis parallel to the optical axis of the lens barrel, is installed inside the manual focusing operation ring. The step gear rotates in conjunction with the internal gear. By the rotation of the step gear, the focus connecting ring and the focus cam cylinder rotate about the optical axis through the interlocking of the small gear of the step gear and the inner gear of the focus connecting ring. By this rotation, the lens mirror chamber is moved in the direction of the optical axis via rollers by the cam cut into the front ring and the focus cam barrel, thereby enabling a focusing operation.

The reduction ratio between the rotor and the focus cam cylinder at this time is the ratio of the number of teeth of the large gear to the number of teeth of the large gear minus the number of teeth of the small gear if the module of each gear is the same. Becomes Incidentally, if the difference between the number of teeth of the large gear and the number of teeth of the small gear is large, the gear ratio becomes small, and if the difference becomes small, the gear ratio becomes large. Therefore, a high gear ratio can be obtained in a direction in which the large gear is reduced.

In the case where the user manually rotates the manual focus operation ring to move the lens mirror chamber, the rotation of the manual focus operation ring causes the step gear to cause friction between the rotor and the stator of the vibration wave motor. It cannot rotate and rotates around a rotation axis parallel to the optical axis fixed to the output ring. Due to this rotation, the focus connecting ring and the focus cam barrel rotate about the optical axis through the interlocking of the small gear of the step gear and the inner gear of the focus connecting ring. By this rotation, the lens mirror chamber is moved in the direction of the optical axis via rollers by the cam cut into the front ring and the focus cam barrel, thereby enabling a focusing operation.

At this time, the reduction ratio between the manual focus operation ring and the focus cam cylinder is equal to the ratio between the number of teeth of the large gear and the number of teeth of the small gear of the step gear if the module of each gear is the same. Incidentally, when the difference between the number of teeth of the large gear and the number of teeth of the small gear is large, the gear ratio increases, and when the difference decreases, the gear ratio decreases.

As described above, the lens barrel according to the present invention can be freely selected and operated without any switching operation from both the manual focus operation ring and the vibration wave motor. By changing the number of teeth, the reduction ratio can be changed. Furthermore, the two different teeth of the stepped gear are pressed against each other by an elastic member such as a spring to provide friction, so that the friction surface can be limited to the end surface of the gear and the gear, and a wide high precision surface is not required. A structure that makes it difficult for dust to adhere to the surface and that can easily adjust friction by a spring can be obtained.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lens barrel according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of a lens barrel according to the present invention, and FIG. 2 is an enlarged detailed view of a stepped gear portion.

In FIG. 1, a lens barrel is an optical system L1,
It has L2, L3, L4, L5, and L6, and is attached to a camera (not shown) by a lens mount 39. Reference numeral 34 denotes a zoom ring for operating the movable lens groups L4 and L5 to change the focal length, and a manual focus operation ring 2 for moving the focus lens L2 and adjusting the focus by an operation during manual focusing.

In FIG. 2, reference numeral 9 denotes a fixed barrel of a lens barrel. A front ring 4 is screwed to the left end, and a motor base 10 is screwed to the outer diameter. The mirror chamber 6 slides the inner diameter of the front ring 4 via a roller 28 screwed along the front ring 4 and a cam groove (not shown) of the focus cam barrel 3 to attach a focusing lens L2. The focus cam cylinder 3 is fitted so as to rotate only within an angle range restricted by the outer diameter of the front ring 4, and a focus connecting ring 11 is connected to the right side so as to be rotatable only within the restricted angle range. .

The step gear is a large gear 12 interlocking with the inner gear 2a of the manual focus operation ring 2, a small gear 13 interlocking with the inner gear 11a of the focus connecting ring 11, and the large gear 12 and the small gear 13 are rotatable. The gear shaft 14 inserted in the state, the gear pressing spring 15 of a helical spring for pressing the large gear 12 and the small gear 13, and the gear shaft 14 for holding the pressing spring 15
, And is inserted into a rotation shaft 7 provided on the output ring 18 and parallel to the optical axis so as to be easily rotated.

The manual focus operation ring 2 has an operation rubber 5 at the outer diameter, and can be freely rotated by 360 ° by the outer diameter of the front cover 1 and the roller 47 shown in FIG. 1 attached to the outer diameter of the front cover 1. So that it is attached. An inner gear portion 2a is provided on the inner diameter, and is linked to the large gear 12 of the step gear. Further, a constant load is applied to the rotation by being pressed radially by a spring portion 1a provided on the front cover 1. Accordingly, when the operating torque of the focus cam barrel 3, the mirror chamber 6, and the focusing lens L2 is heavy, the output from the rotor 19 loses the weight of the focus cam barrel 3, the mirror chamber 6, and the focusing lens L2, and the step gear Is prevented from rotating with the focus connecting ring 11 as a floor and turning the manual focus operation ring 2.

A vibration wave motor serving as a drive source of the autofocus is one of a ring-shaped vibration absorber 21 made of a ring-shaped vibration member to which an electrostrictive element 27 is adhered, felt, rubber, and the like, and one of the vibration absorber 21. Annular stator guide 22 disposed in contact with an end face of the motor spring 2, and a motor spring 2 for pressing the stator guide 22 toward the stator 20.
3. A spring base 2 for holding down the motor spring 23
4. Stator stopper 2 to stop rotation of stator 20
6. The rotor 1 which rotates by the vibration of the stator 20
9, a cushion rubber 25, and an output ring 18 are constituted by various members such as a motor base 10 which engages the above members on the outer diameter side.

The rotor 19 rotates in the optical axis concentric direction by the circumferential traveling wave vibration generated by the stator 20. At this time, the stator guide 22, the vibration absorber 21, and the stator 2 sandwiched between the spring base 24 and the motor base 10.
The motor spring 23 presses and fixes the rotor 0, the rotor 19, the cushion rubber 25, the output ring 18, and the bearing 17. Therefore, the rotor 19 is pressed against the output ring 18 and the right end face of the bearing 17 and rotates together with a part of the bearing 17. At this time, the large gear 12 of the step gear rotating around the rotation axis parallel to the optical axis fixed to the output ring 18 and the inner gear 2 of the manual focus operation ring 2
In conjunction with a, the step gear is rotated about the optical axis. With this movement, the focus connecting ring 11 and the focus cam barrel, which are interlocked with the small gear 13 of the step gear, rotate around the optical axis to move the mirror chamber 6 and the focusing lens L2.

In operation from the manual operation ring 2, the manual focus operation ring 2 is manually rotated. At this time, the inner gear 2a cut into the manual focus operation ring 2 is interlocked with the large gear 12 to rotate the step gear. By this movement, the focus connecting ring 11 and the focus cam barrel 3 that are linked to the small gear 13 rotate around the optical axis, and move the mirror chamber 6 and the focusing lens L2.

At this time, if the friction between the rotor 19 and the stator 20 due to the pressurization is not sufficient, the manual focus operation ring 2 is manually rotated. There is a possibility that the rotor 19 and the stator 20 may slip out of rotation. Here, the step gear is divided into two parts, a large gear 12 and a small gear 13, and the spring pressure of the gear pressing spring 15 is adjusted so that the rotor 1
9. Set so that the divided large and small gears slip before the stator 20 slips. Thereby, even when the pressure holding force between the rotor 19 and the stator 20 is set to be weak, the slip between the rotor 19 and the stator 20 can be prevented.

[0031]

As described above, the lens barrel according to the present invention comprises a driving member having a fixed rotation axis parallel to the optical axis of the lens barrel, and two different numbers of teeth rotating about the rotation axis. A gear having a step gear, a focus lens moving ring rotatable around the optical axis, and a manual operation ring, and a structure in which the focus lens moving ring and the manual operation ring have an interlocking unit for interlocking the step gear. By doing so, the step gear is made differential. Thereby, the focus lens moving ring can be driven without switching operation between the auto focus drive and the manual focus drive, and the reduction ratio of the vibration wave motor to the drive of the focus cam cylinder 3 can be changed. Above, the two different teeth of the step gear are pressed against each other by an elastic member such as a spring, so that friction is provided, so that the friction surface is limited to the end surface of the gear and the gear, so that a wide high precision surface is not required. In addition, it is possible to obtain a structure in which dust easily adheres to the friction surface and the friction can be easily adjusted by the spring.

In the embodiment of the present invention, a winding spring is used as the elastic member to press the step gear, but elasticity of a disc spring, a wave washer, rubber or the like may be used. Although the spur gear is used for interlocking the step gear with the manual focus operation ring and the focus connecting ring, it goes without saying that a bevel gear or a helical gear can be used without any problem.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lens barrel according to the present invention.

FIG. 2 is an enlarged detailed view of a vibration wave motor and a step gear portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front cover 2 Manual focus operation ring 3 Focus cam cylinder 4 Front ring 5 Operation rubber 6 Mirror room 9 Fixed cylinder 10 Motor base 11 Focus connection ring 12 Large gear 13 Small gear 14 Gear shaft 15 Gear pressurizing spring 16 Spring retainer 17 Bearing 18 Output Ring 19 Rotor 20 Stator 21 Vibration Absorber 22 Stator Guide 23 Motor Spring 24 Spring Base 25 Buffer Rubber 26 Stator Stop 27 Electrostrictive Element 28 Roller 34 Zoom Ring 39 Lens Mount 47 Roller

Claims (2)

[Claims] 1. A lens barrel having an oscillating wave motor, comprising: a driving member having a fixed rotation axis parallel to the optical axis of the lens barrel; and two different numbers of teeth rotating about the rotation axis. A step gear, a focus lens moving ring rotatable around an optical axis, and a manual operation ring, wherein the focus lens moving ring and the manual operation ring are provided with an interlocking unit for interlocking the step gear. Lens barrel. 2. The step gear according to claim 1, wherein the step gear is divided into a large gear and a small gear, and the large gear and the small gear are pressed against each other by an elastic member so that the step gear has friction. Lens barrel.