JPH03182709A - Lens barrel - Google Patents

Abstract

PURPOSE:To smoothly and surely drive the lens by receiving pressure force of automatic and manual operating force transfer members by a roller part and providing a gear part in which a gear part of a rotary member is engaged to the automatic and manual operating force transfer members. CONSTITUTION:A rotary member 17 for constituting a planetary mechanism receives pressure force of an automatic operating force transfer member 19 and a manual operating force transfer member 24 by its roller part 20a. Accord ingly, a gear part 24a of the automatic operating force transfer member 19 and the manual operating force transfer member 24 engaged to its gear part 20b can be set to a center distance for giving a suitable backlash, and the lens can be driven by frictional driving by the roller part 20a at the time when a load of the lens L is small, and by engagement of the gear part in the case the load of the lens L is large. In such a way, a manual focus operation and an auto focus operation can be switched by a non-converting operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lens barrel incorporating an annular vibration wave motor, and particularly to a lens barrel that can perform autofocus operation and manual focus operation without using a switching mechanism. This invention relates to a lens barrel with a built-in focusing motor.

[Conventional technology] Conventionally, an autofocus motor was built into the lens barrel body,
In an autofocus lens barrel configured to selectively perform an autofocus operation and a manual focus operation, a ring-shaped vibration wave motor is known as the autofocus motor. A device has been proposed in which an autofocus operation and a manual focus operation can be performed without using special switching means.

The mechanism in this lens barrel that allows autofocus operation and manual focus operation to be performed without using special switching means utilizes a differential mechanism using rollers in the planetary mechanism. The roller has a rotation axis in a radial direction perpendicular to the optical axis. Then, a differential mechanism is configured such that the roller of the planetary mechanism is sandwiched between the output end face from the manual ring for manual focus operation and the output end face of the vibration wave motor for autofocus operation, and the output The focusing lens is driven on the side, and the features of the vibration wave motor structure are fully utilized, especially during manual focusing operations.

As is well known, in a vibration wave motor, an annular rotor, which serves as an output member, is pressed against an annular metallic elastic body (corresponding to a stator) in which traveling waves are formed, using a pressure member such as a spring. The rotor is frictionally driven by a traveling wave formed in the elastic body, and the manual ring does not rotate even if the output member, which receives the pressing force of the pressing member along the optical axis direction, rotates. For example, when the pressing force of the pressure member acts to maintain the state, and when the manual ring is rotated to perform manual focusing, the rotor of the vibration wave motor is in pressure contact with the stator. The rotor is maintained non-rotating, and switching between autofocus operation and manual focus operation can be performed without using any switching mechanism.

[Problems to be Solved by the Invention] However, in the conventional lens barrel described above, a roller is used in the planetary mechanism in the differential mechanism for switching between manual focusing operation and autofocusing operation without conversion. The drive force was transmitted by bringing the output end faces of the vibration wave motors on both sides of the roller into frictional contact with the end faces of the focus ring, so when driving a focus lens with a large lens load, the frictional contact with the rollers could cause slippage. There is a possibility that the output from the vibration wave motor cannot be efficiently transmitted, and the lens cannot be driven sufficiently.

For this reason, such a configuration is disadvantageous for lenses with a large lens load, and as a countermeasure to this problem, it has been proposed to use gears in place of the rollers of the planetary mechanism. Similar to the case of the roller described above, a gear is rotatably attached to the rotating shaft in the direction perpendicular to the optical axis, and gears that mesh with the gear are attached to the output end face of the vibration wave motor and the end face of the output ring of the manual ring, respectively. The configuration is as follows.

In this case, since the drive source for autofocus is a vibration wave motor, the output end face of the vibration wave motor is subjected to the pressing force of a disc spring or the like to press the elastic body and the rotor, and the gear The gears arranged along the axis distance direction, that is, along the optical axis direction, rotate in a meshed state, resulting in extremely poor gear efficiency.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a lens that can switch between manual focus operation and autofocus operation without conversion, which can drive the lens efficiently even when the lens load is large. It provides a lens barrel.

[Means to solve the problem]

The structure of the lens barrel for achieving the purpose of the present invention is such that the output from an annular vibration wave motor placed concentrically with the optical axis of the lens is transmitted, and an automatic operating force is driven to rotate around the optical axis. a transmission member; a rotating member disposed at at least three force points on a circumference centered on the optical axis of the lens and rotatable about a radial axis perpendicular to the optical axis;
A driving member that rotatably supports these rotating members and drives the lens in conjunction with rotation about an optical axis together with these rotating members, and the automatic operation force transmission member is pressed against the outer peripheral surface of these rotating members. a pressurizing means rotatable about an optical axis, one end face of which is disposed opposite to the automatic operation force transmission member with the rotating member interposed therebetween;
A predetermined frictional resistance is applied to the manual operating force transmitting member that contacts the rotating member and the manual operating force transmitting member, and the end face of the manual operating force transmitting member is In a lens barrel equipped with a manual operation force input member that is brought into pressure contact with the outer circumferential surface of a rotating member, the rotating member has a roller portion and a gear portion, and the roller portion allows the automatic operation force transmission member and the manual operation force input member to be connected to each other. The present invention is characterized in that a gear portion is provided which receives the pressing force from the operating force transmitting member and meshes with the gear portion of the rotating member with the automatic operating force transmitting member and the manual operating force transmitting member.

[Function J] In the lens barrel configured as described above, the rotating member constituting the planetary mechanism receives the pressing force of the automatic operating force transmitting member and the manual operating force transmitting member at its roller portion. Since the distance between the axes of the automatic operation force transmission member meshing with the gear part and the gear part of the manual operation force transmission member can be set to provide an appropriate backlash, when the load on the lens is small, the roller part The lens can be driven by friction drive or, if the load on the lens is large, by meshing gears.

[Embodiment] Fig. 1 is a vertical cross-sectional view of a main part showing an embodiment of a lens barrel according to the present invention, and Fig. 2 shows a vibration wave motor detachably incorporated in the lens barrel of Fig. 1. FIG. 2 is a longitudinal cross-sectional view of the driving force generation unit.

In FIGS. 1 and 2, 1 is a fixed cylinder having an inward flange 1a, 2 is an outer cylinder having an inward flange 2a,
3 is a cam cylinder which is fastened to an inward flange 7a of a cylindrical body 7, which will be described later, with a screw 4, and has a cam groove 3a formed in the cylindrical part; 5 is a lens holder fitted into the inner diameter part of the cam cylinder 3; Reference numeral 6 denotes a cam screw that fits into the cam groove 3a of the cam cylinder 3 and is fixed onto the lens holder 5, and L indicates a lens fixed to the lens holder 5.

Reference numeral 7 denotes a cylindrical body serving as a frame or base plate of a driving force generating unit A to be described later, and the inward flange 2a of the outer cylinder 2 is connected to the outward flange 7b of the cylindrical body 7, and screws 8.
The driving force generation unit is configured in a state where the two are fastened together (see Fig. 2). Further, the inward flange la of the fixed cylinder 1 is attached to the inward flange 7a of the cylindrical body 7 with screws 9.
The structure is such that the fixing tube 1 is fixed by being fastened by the fixing tube 1. Reference numeral 10 is fitted into a circumferential groove formed on the outer circumferential surface of the fixed cylinder 1 and a circumferential groove formed on the outer circumferential surface of the cylindrical body 7, and is centered about the central axis 112 (that is, the optical axis) of the lens L. It is a manual operation ring that can be rotated as follows.

As shown in FIG. 2, on the outer peripheral surface of the cylindrical body 7, all the components of the vibration wave motor B, a motor bearing/output member C, etc. that come into contact with a part of the rotor of the vibration wave motor B are mounted. has been done.

The constituent members of the vibration wave motor B, the structure of the motor bearing/output member C, etc. will be described below.

The vibration wave motor B includes an annular vibration member 11 having a trapezoidal cross-sectional shape, an electrostrictive element 12 physically joined to one end surface of the vibration member 11, and a felt pressure-welded to the surface of the electrostrictive element 12. an annular vibration absorber 13 consisting of a vibration absorber 13, an annular disc spring 14 that pushes the vibration absorber 13 toward the vibration member 11, and an annular disc spring 14 that holds the pressing force of the disc spring 14 between it and the cylindrical body 7. A holding member 15, an annular circumferentially moving member 16 which is the rotor of the vibration wave motor B, a rotating cylinder 17 that can rotate integrally with the circumferentially moving member 16, and a connection between the rotating cylinder 17 and the circumferentially moving member 16. A rubber ring 18 is tightly sandwiched between the rubber ring 18 and prevents the axial movement (i.e., chatter vibration) of the circumferentially moving member 16 from being transmitted to the rotary cylinder 17, and the rubber ring 18 is provided on the cylindrical body 7 and is attached to the vibrating member. The vibrating member rotation stopping protrusion 7C1 is inserted into the groove 11a of the vibrating member 11 and prevents the vibrating member 11 from rotating.

This vibration wave motor B includes a circumferential moving member 16, a rotary cylinder 17, and a rubber ring 1, which are configured to be able to rotate integrally by the circumferential traveling wave vibration generated in the vibrating member 11.
8 rotates around the optical axis Z.

As shown in FIGS. 2 and 3, the motor shaft/output member C disposed adjacent to the end surface of the rotary tube 17 of the vibration wave motor B is rotatably attached to the outer peripheral surface of the cylindrical body 7. The fitted ring 19 and the outer peripheral surface of the ring 19 at at least three locations on the circumference of the ring 19 on the radial axis perpendicular to the axis Z of the ring 19 (the axis of the vibration wave motor, that is, the optical axis). A roller support shaft 19 provided to protrude from
a, a roller 20 that is rotatably fitted to the roller support shaft 19a, and a washer 21 that supports the roller 20 so that it does not come off the roller support shaft 19a.

The roller 20 is also provided with a roller portion 20a and a gear portion 20b, and the gear portion 20b includes a gear portion 17b (face gear, etc.) provided on the rotary cylinder 17, and a gear portion 17b (such as a face gear) provided on the manual operation force connection ring 24, which will be described later. The gear portions 24a (face gears, etc.) are connected by gears.

The ring 19 also serves as an output member of the driving force generating unit A, and serves as an L for rotationally driving the lens holder 5.
A shaped lens holder driving member 22 is fastened to the end surface of the ring by screws 23. The lens holder driving member 22 is provided with a notch 22a, and the cam screw 6 is fitted into the notch 22a, so that the lens holder 5 can be rotated by the operation of the lens holder driving member 22. can be done. Further, the roller 2
The outer circumferential surface 17a of the rotary cylinder 17 engages with the end surface of the rotary cylinder 17,
This prevents rattling in the radial direction when the rotary cylinder 17 rotates. Furthermore, in the roller portion 20a of the roller 20, the end surface 17c of the rotary cylinder 17 and the end surface 24b of the manual operation force coupling ring 24 are brought into contact with each other due to the rotation of the manual operation ring 10. the roller 2
The mutual contact pressure between the roller part 20b of 0, the end surface 17c of the rotary cylinder 17, and the end surface 24b of the manual operation force connection ring 24 is caused by the disc spring 1, which is a component of the vibration wave motor B.
It is determined by the pressing force of 4.

Note that the gear portion 20b of the roller 20 and the rotary cylinder 17 described above
The distance between the gear axes between the gear portion 17b of the roller 20 and the gear portion 24a of the manual operation force connection ring 24 is determined by the distance between the roller portion 20a of the roller 20 and the end surface 17c of the rotary cylinder 17 and the end surface 24b of the manual operation force connection ring 24. determined by

That is, it is determined by the outer diameter dimension of the roller portion 20a of the roller 20.

Reference numeral 25 denotes a manual operation force input ring which is a frictional force stabilizing member that is rotatably fitted into the cylindrical body 7, and is frictionally connected to the manual operation force connection ring 24, and normally both rings 24, 25 are constructed so that they can rotate as a unit. Only when the manual operation force coupling ring 24 is prevented from rotating, the manual operation force input ring 25 can rotate independently.

On the other hand, since the manual operation force input ring 25 rotates with one end surface in contact with the cylindrical body 7, the manual operation force input ring 25 is frictionally stabilized in order to make the rotation smooth (to improve the feeling of manual operation). It is used as a component. The configuration for rotating the manual operation force input ring 25 is such that the outer peripheral edge of the manual operation force input ring 25 engages with a recess in the inner peripheral surface of the manual operation ring 10, so that the manual operation force input ring 25 is rotated by the manual operation ring 10. It looks like this.

The manual operation force input ring 25 can rotate only when a driving torque larger than the frictional resistance with the cylindrical body 7 is transmitted from the manual operation ring 10, and does not rotate at other times. Therefore, the user of the lens barrel can apply the rotational torque that overcomes the frictional resistance between the manual operation force input ring 25 and the cylindrical body 7 to the manual operation ring 1.
The manual operation force connection ring 24 does not rotate unless the manual operation force connection ring 24 is rotated.

A pulse plate holder 26 is sandwiched between the cylindrical body 7 and the outer cylinder 2 and is rotatable around the optical axis Z. A pulse plate 27, which will be described later, is fixed to the left end, and a pulse plate holder 26 is fixed to the right end. It has a projection 26a, and the projection 26a passes through the hole in the cylindrical body 7 and engages with the groove 19b of the ring 19, so that it can rotate integrally with the ring 19. There is. 27 is a pulse plate formed with a large number of slits. Reference numeral 28 is a photoelectric transmission type for detecting the rotation of the pulse plate 27 about the optical axis Z using a slit portion of the pulse plate 27, and sending a signal to a control circuit (not shown) to control and drive the vibration wave motor B. switch. 29 is the photoelectric transmission type switch 28
The switch holding plate is fixed to the cylindrical body 7 by a well-known method.

30 is a contact brush fixed to the ring 19;
The ring 19 is rotated to slide on a flexible printed board 31 provided on the outer periphery of the cylindrical body 7 . The role of this contact brush 30 is to transmit information on the distance between (1) and the closest point in focus, and information on the (2) end and the closest end to a circuit (not shown).

Next, the operation of the above structure will be explained.

When a lens barrel user wants to drive the lens holder 5 with the force of his fingers, he moves the manual operation ring 10 along the optical axis Z.
Rotate with your finger around . Then, the manual operation force input ring 25 overcomes the frictional resistance with the cylindrical body 7 and rotates together with the manual operation force connection ring 24 about the optical axis 2, but at this time the vibration wave motor B is not driven. Therefore, the rotating cylinder 17 of the vibration wave motor B
is stationary due to the frictional force between the vibrating member 11 and the circumferentially moving member 16, and therefore, the roller 20 is rotated by the manual operation force coupling ring 24 and transferred along the end surface of the rotary cylinder 17. As a result, the roller support shaft 19
The ring 19 is rotated about the optical axis Z through the lens a, and the lens holder 5 is rotated by the engagement between the lens holder driving member 22 and the cam screw 6, and the lens holder 5 is rotated along the cam groove 3a of the cam barrel 3. Manual focusing is performed by moving in the direction.

On the other hand, when the lens barrel user wants to drive the lens holder 5 with the force of the vibration wave motor B, he operates a focusing switch (not shown). Then, a voltage is applied to the electrostrictive element 12 by the operation of a control circuit (not shown), and as a result, vibrations that proceed in the circumferential direction are generated in the vibrating member 11, and the vibrations of the vibrating member 11 cause the circumferentially moving member 16 and The rubber ring 18 and the rotary tube 17 are rotated around the optical axis Z. Due to this rotation, the roller 20 receives rotational torque from the rotary tube 17, but at this time, the manual operation ring 10 is not rotated, so the manual operation force input ring 25, the manual operation force connection ring 24
Since the roller 20 is not rotating, the roller 20 rolls along the end surface of the manual operation force input ring 24 while rotating around the roller support shaft 19a.
The ring 19 is rotated around the optical axis Z via a. Therefore, the lens holder 5 is rotated by the engagement between the lens holder driving member 22 and the cam screw 6, and moves in the axial direction along the cam groove 3a of the cam cylinder 3, thereby performing autofocusing.

As for the configuration during manual focusing and autofocusing, when the load on the lens L is small, the roller portion 20a1 of the roller 20, the end portion 17c of the rotating barrel 17,
, the manual operation force is frictionally driven by contact with the end surface 24b of the coupling ring 24, and when the load on the lens L is large, the gear portion 20b of the roller 20 and the gear portion 17b of the rotating barrel 17 are driven by friction.
, and the gear portion 24a of the manual operation force connection ring 24 to be gear-driven.

By the way, one of the conditions for stabilizing the friction drive and gear drive mentioned above in the case of manual focusing and autofocusing is to stabilize the pressing force value of the disc spring 14, so in this embodiment, the following disc The pressing force of the spring 14 is adjusted. This state is the fourth
This is shown in Fig. 5. The symbols are the same as in FIGS. 1 to 3.

The cylindrical body 7 has a tapered cam groove 70 and a straight groove 7d.
Bayonet grooves (bayonet grooves) are provided at three equal locations. The holding member 15 is provided with three protrusions 15a corresponding to the three grooves. Further, the holding member 15 is provided with three holes 15b that engage with three bottles provided in a weight (not shown).

In this structure, one embodiment of the pressurizing force adjustment method will be described.

First, in a state where the vibration member 11, electrostrictive element 12, vibration absorber 13, etc. of the vibration wave motor are assembled into the cylindrical body 7,
The disc spring 14 is inserted into the cylindrical body 7 and placed on the vibration absorber 13. Then, from above, the three protrusions 1 of the holding member 15
5a is inserted into the straight groove 7d of the cylindrical body 7. In this state, a weight (not shown) corresponding to the set pressing force value is placed on the holding member 15 by aligning the three bottles of the weight with the three holes 15b of the holding member 15. If this state is maintained, the applied pressure value will be adjusted to the set pressure value. That is, as a holding method, the holding member 15 on which the weight is mounted is rotated clockwise until it comes into contact with any point of the tapered cam portion of the tapered cam groove 7c of the cylindrical body 7 (see FIG. 5), and the holding member 15 is held in this state. If the protrusion 15a of the holding member 15 is bonded to the tapered cam groove 7C, the pressing force can be maintained even if the weight is removed. Hole 15b
The reason for this is that when the holding member 15 is rotated until it comes into contact with any point on the tapered cam portion of the tapered cam groove 70 of the cylindrical body 7, even if the weight itself is rotated, the bottle cannot be engaged. Holding member 1
This is because 5 is made rotatable.

〔Effect of the invention〕

As explained above, according to the present invention, the rotating member constituting the planetary mechanism receives the pressing force of the pressing means at the roller portion, thereby connecting the gear portion and the gear portion of the manual and automatic operation force transmitting member. Appropriate backlash can be given to the gear train of the lens, and when the lens load is small, the roller part can be used as a friction drive, and when the lens load is large, the gear can be driven by the gear part. The lens can be driven smoothly and reliably.

Furthermore, since the distance between the gear axes of the gear section is determined only by the accuracy of the outer diameter dimension of the roller section, there is little variation in gear backlash from product to product, and highly accurate lens position control can be performed.

Furthermore, since there is almost no difference in structure compared to a conventional differential drive configuration using only friction drive using rollers, the above effects can be obtained with almost no impact in terms of space and cost.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a lens barrel according to the present invention, FIG. 2 is a longitudinal sectional view of a driving force generating unit A thereof,
FIG. 3 is a front view of the motor bearing/output member C, FIG. 4 is a perspective view showing an embodiment of the pressure adjustment mechanism of the vibration wave motor, and FIG. 5 is a view of the pressure adjustment mechanism in FIG. It is a partial diagram. 7... Cylindrical body (fixed support member) 7c... Tapered cam groove 7d... Straight groove 11... Vibration member 12... Electrostrictive element 13.
... Vibration absorber 14 ... Belleville spring (pressurizing means) 15 ... Holding member 15a ... Protrusion 16 ...
- Circumferential moving member 17...Rotating cylinder 17, b...Gear portion 17c...End portion 18...Rubber ring
19...Ring 20...Roller 2
0a...Roller portion 20b...Gear portion 24...Manual operation force connection ring 24a...Gear portion 24b...End portion 25...Manual operation force input ring. 4 other people

Claims (1)

[Scope of Claims] 1. An automatic operation force transmission member to which an output from an annular vibration wave motor disposed concentrically with the optical axis of the lens is transmitted, and which is rotationally driven around the optical axis; Rotating members arranged at at least three locations on the circumference of the center and rotatable around a radial axis perpendicular to the optical axis;
A driving member that drives the lens in conjunction with rotation about the optical axis together with these rotating members, a pressing means that presses the automatic operation force transmission member against the outer peripheral surface of these rotating members, and a driving member that rotates about the optical axis. a manual operating force transmitting member in contact with the rotating member; Along with providing frictional resistance,
A lens barrel including a manual operation force input member that presses an end face of the manual operation force transmission member against an outer circumferential surface of each of the rotating members by a reaction force of the pressurizing force by the pressurizing means, wherein the rotating member is a roller. and a gear part, the roller part receives the pressing force of the automatic operation force transmission member and the manual operation force transmission member, and the automatic operation force transmission member and the manual operation force transmission member receive the rotational force. A lens barrel characterized in that a gear portion is provided with which the gear portion of the member meshes. 2. Preventing the manual operating force transmitting member from rotating in response to the rotational drive of the automatic operating force transmitting member, and preventing the automatic operating force transmitting member from rotating in response to the rotational drive of the manual operating force transmitting member. Claim 1, wherein the static frictional resistance of the manual operation force transmission member is determined in accordance with the present invention.
The lens barrel described in.