JP2000162488A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel for an AF single lens reflex camera to allow manual distance adjustment requiring no conversion of drive force once provided into a gear train even when applied to a hollow motor using an optical axis as a center, without requiring plural gear trains. SOLUTION: Balls 15a, 15b are contained into two wedge-shaped spaces formed with respect to sloped faces 14a, 14b of a cam plate 14 and an end face 12b of a clutch ring 12, the balls 15a, 15b are pressed in between the sloped faces 14a, 14b of the cam plate 14 and the end face 12b of the clutch ring 12 by springs 16a, 16b with respective one-ends abutting to end faces 14c, 14d of the cam plate 14, pressure is applied on an abutting face between an automatic adjusting cylinder 5, the clutch ring 12, the balls 15a, 15b and the cam plate 14, between an end face 5a of the cylinder 5, end faces 12d, 12c of the clutch ring 12 and the balls 15a, 15b, between the balls 15a, 15b and the sloped faces 14a, 14b of the cam plate 14, and between the an end face 14e of the cam plate 14 and the end face 12c of the clutch ring 12, and frictional forces are applied between the respective faces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system camera, particularly to a lens barrel of an interchangeable lens of a single-lens reflex camera. The present invention relates to a lens barrel of a single-lens reflex camera.

[0002]

2. Description of the Related Art In an AF single-lens reflex camera, a manual switch mechanism is provided in a manual distance adjustment mechanism of an in-body motor type and an in-lens motor type AF dedicated interchangeable lens, and a method of switching between an interlocking system of a driving motor and a manual interlocking system is known. General. However, at the time of use, there is a problem due to the inconvenience of the switching operation and the timing of shooting.
Also, from the viewpoint of protection of the drive motor, when the distance ring is turned by hand, the motor drive force is transmitted to the distance adjustment cylinder when the motor is driven so that the manual force is not transmitted back to the motor side, and the automatic distance adjustment by the motor is performed. On the other hand, when manual adjustment is performed from the manual distance adjustment barrel, a lens barrel having a power transmission mechanism having a structure in which power can be adjusted without switching operation and power from the manual side is not transmitted to the motor side Has been proposed by Japanese Patent Application No. 10-192328.

[0003]

However, according to this method, although the clutch mechanism itself is compactly arranged, depending on the configuration of the lens barrel, it is difficult to achieve a three-dimensional structure.
Three gear trains, one from the motor to the clutch, from the manual ring to the clutch, and from the clutch to the lens drive, are required, thus complicating the overall configuration. Furthermore, even when used in a hollow motor centered on the optical axis, the method requires conversion of the driving force once obtained into a gear train, thus complicating the structure and deteriorating efficiency. There were also problems. Therefore, there has been a demand for a method which is compact as a whole and does not reduce the degree of freedom of design, while following the above method in principle.

[0004]

According to the present invention, in order to solve such a problem, a clutch mechanism unit is provided around an optical axis along a ring near a manual adjustment ring and a distance adjustment ring. A compact lens barrel that can be applied to any type of motor, such as motors and hollow motors, has been developed.

More specifically, an automatic adjustment cylinder separated from a manual adjustment cylinder is provided for a distance adjustment cylinder that enables focus adjustment by moving a moving lens of a photographing optical system in the optical axis direction by driving a motor. In the focus adjustment by motor drive, the automatic adjustment cylinder and the manual adjustment cylinder rotate integrally, and the distance adjustment cylinder can be moved, but when a manual operation force is applied to the manual adjustment cylinder, At the first stage, the connection from the motor is cut off, and after that, a clutch mechanism that functions so that the automatic adjustment cylinder and the manual adjustment cylinder can move the distance adjustment cylinder integrally is unitized, installed around the lens barrel circumference, and the clutch mechanism unit is installed. A cylindrical driving interlocking member having a groove on the circumference connected to the driving side, a driven interlocking member connected to the driven side abutting on the driving interlocking member, and a cam member having a left-right symmetric inclined surface are connected to the driving interlocking member. Element A clutch holding plate to which the cam member is fixed so as to be located in the groove portion is provided around the driven interlocking member, and a wedge-shaped gap is formed between the end surface of the groove formed on the drive interlocking member and the cam member. A mechanism for connecting a drive side and a driven side by keeping a rolling state between the drive interlocking member and the cam member by pressing a rollable ball or roller under pressure of a spring, and the manual adjustment. A connection release mechanism is provided in which a release pin extending from the cylinder is inserted into the gap between the left and right balls or rollers at the apexes of both inclined surfaces of the cam member.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Normally, a drive side and a driven side are locked in a clutch mechanism. During an automatic focusing operation, a distance adjusting cylinder receives rotational power from a motor to automatically perform a focus adjusting operation. A connection system has been established. on the other hand,
When the manual operation power is applied to the manual adjustment cylinder, the manual force acts to release the lock in the clutch mechanism, and the driven side slides and runs idle to the motor side to cut off the connection system and to the motor side. It is not structured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment of the present invention will be described below with reference to the drawings and the like, using a lens barrel capable of performing a zoom operation.

FIG. 1 is a schematic perspective view of a clutch mechanism unit employed in the lens barrel of the present invention, and FIG. 2 is an explanatory view of the operation of the clutch mechanism unit. FIG. 5 is a sectional view of a lens barrel of the present invention equipped with a clutch mechanism unit.
4 shows an embodiment of a motor type in a lens. In the drawings, the same members are denoted by the same reference numerals.

In the sectional view of the lens barrel shown in FIG.
In an optical system composed of lens groups L1, L2, and L3 centered at 0, focus adjustment is possible by moving lens group L2 straight with respect to other lens groups, and further, lens groups L1, L2, and L3. 2 shows an example of a lens barrel that can perform a zooming operation by performing relative displacement.

The lens group L2 is held by a holding frame 1, and the helicoid portion 2a of the distance adjusting cylinder 2 to which the holding frame 1 of the lens group L2 is fixed and the helicoid portion 3a of the moving cylinder 3 are fixed.
And the movable barrel 3 and the distance adjusting barrel 2 can move linearly integrally with the fixed barrel 4. Further, since the focusing lever 6 fixed to the holding frame 1 is fitted into the straight key groove 5a inside the automatic adjustment cylinder 5, the rotation of the automatic adjustment cylinder 5 can be transmitted to the distance adjustment cylinder 2 and the moving cylinder 3
Due to the change in the relative angle between the distance adjustment cylinder 2 and the distance adjustment cylinder 2, the straight-moving positions of the distance adjustment cylinder 2 and the lens group L2 of the holding frame 1 with respect to the moving cylinder 3 are changed, and the focus adjustment of this lens barrel is possible.

Further, a manual adjustment cylinder 7 rotatable with respect to the automatic adjustment cylinder 5 is fitted to the automatic adjustment cylinder 5, and is installed at the outermost peripheral position of the lens body so as to be manually operable.

On the other hand, the power from the motor 8 is connected to the internal tooth tube 10 through the speed reduction mechanism 9, and is linked with the automatic adjustment tube 5 via the clutch mechanism unit 11.

In the configuration of the lens barrel shown in FIG. 5, in the automatic focus adjustment operation when the motor is driven, the crutch mechanism unit 11 is used.
The automatic adjustment cylinder 5 which is a driven interlocking member engaged with the driving ring by the clutch ring 12 which is a driving interlocking member, and the light-weight manual adjustment cylinder 7 loosely fitted around the automatic adjustment cylinder 5 are integrally formed in the inside. The pin holding plate 1 in which the release pin 17 is implanted is turned to a motor driven automatic focus adjustment operation state in which the focus adjustment can be performed by rotating and moving the distance adjustment cylinder 2 straight.
When a manual operation force is applied to the manual adjusting cylinder 7 to which the fixing member 8 is fixed, the automatic adjusting cylinder 5 and the manual adjusting cylinder 7 are displaced by a relative angle, and the clutch ring 12 on the driving side and the automatic clutch on the driven side are shifted inside the clutch mechanism unit 11. The connection of the adjusting cylinder 5 is released, and the distance adjusting cylinder 2 can be moved by manually rotating the automatic adjusting cylinder 5.
1 will be described in detail below.

The driving force obtained from the motor is transmitted to a pinion 9a via a speed reduction mechanism 9, and the pinion 9a meshes with an internal tooth 10a of an internal tooth tube 10 on the driving side. The inner tooth tube 10 and the clutch ring 12 are connected, and FIG.
As shown in a schematic perspective view of the clutch mechanism unit, a groove 12 a is formed on the outer peripheral surface of the clutch ring 12. A cam plate 14, which is a cam member fixed to the automatic adjustment cylinder 5 via a cam holding plate 13, is disposed in the groove 12a so as to be relatively movable in the groove 12a. The cam plate 14 has inclined surfaces 14a and 14b which are symmetrical to each other so that a wedge-shaped gap is formed with respect to the end surface 12b of the clutch ring 12.

The balls 15a and 15b are respectively inserted into two wedge-shaped spaces formed with respect to the inclined surfaces 14a and 14b of the cam plate 14 and the end surface 12b of the clutch ring 12, and one end is formed on the concave end surfaces 14c and 14d of the cam plate 14. Pressure is applied by springs 16a and 16b to which the balls 15a and 15b are pushed between the inclined surfaces 14a and 14b of the cam plate 14 and the end surface 12b of the clutch ring 12, respectively. As a result, the automatic adjustment cylinder 5, the clutch ring 12, the balls 15a and 15b, the cam plate 14
, The end face 5a of the automatic adjustment cylinder 5, the end faces 12d and 12c of the clutch ring 12, and the balls 15a and 1
5b, a pressing force acts between the balls 15a, 15b, the inclined surfaces 14a, 14b of the cam plate 14, and the end surface 14e of the cam plate 14 and the end surface 12c of the clutch ring 12, so that friction between the respective surfaces. Power works.

A pin holding plate 18 having a release pin 17 planted thereon is fixed to the manual adjustment cylinder 7, and the release pin 17 is inserted into a gap between the balls 15a and 15b.
The relative rotational displacement between the distance adjusting cylinder 2 and the manual adjusting cylinder 7 is defined by the release pin 17 being restricted by the elongated hole 13a. Then, the release pin 17 and the ball 15a,
The play amounts 13b and 13c with respect to 15b are set to be smaller than the restriction amounts 13d and 13e by the elongated holes 13a.

Next, the operation of the clutch mechanism unit 11 will be described in detail with reference to FIG. Now, let us consider a case where the drive rotation from the motor is transmitted to the clutch ring 12 in the clockwise direction about the center in the optical axis direction. 2, 3 and 4 are explanatory diagrams of the operation of the clutch mechanism unit. In FIG. 2, when the motor is driven,
The manual adjustment cylinder 7 is fitted to the automatic adjustment cylinder 5 so that the release pin 17 has very little play 13b, 13c between the two balls 15a, 15b. For the reasons described above, the automatic adjustment cylinder 5, the clutch ring 12, the balls 15a, 15b, and the springs 16a, 16b are used.
The contact surface between the cam plates 14, the end surface 5a of the automatic adjustment cylinder 5.
And the end faces 12d and 12c of the clutch ring 12 and the balls 15a and 15b, the balls 15a and 15b and the inclined faces 14a and 14b of the cam plate 14, and the end face 14 of the cam plate 14.
When a pressing force acts between e and the end face 12b of the clutch ring 12, a frictional force acts between the respective faces. as a result,
By rotating the clutch ring 12 about the optical axis,
The ball 15b is rotationally urged to bite into the wedge. As a result, the pressing force becomes excessively large as compared with that of the spring, and a lock state occurs due to the frictional force at each contact surface, so that the automatic adjustment cylinder 5 and the clutch ring 12 further engage with the fitting portion of the automatic adjustment cylinder 5. The rotation urging or release pin 17 is rotationally urged via the ball 15b due to the friction of the manual adjustment cylinder 7 to rotate integrally.

Next, consider the case of manual operation. As shown in FIG. 3, the release pin 17 is arranged in the gap between the balls 15a and 15b, and the manual adjustment cylinder 7 is loosely fitted to the automatic adjustment cylinder 5, so that the inertia resistance of the distance adjustment cylinder 2 and the Due to the motor stoppage resistance and the coupling force of the clutch, only the manual adjustment cylinder 7 moves until the release pin 17 contacts the ball 15a.

When the release pin 17 is further moved,
In order to move the ball away from the wedge, the locked state of the automatic adjustment cylinder 5 and the manual adjustment cylinder 7 is released. Then, the springs 16a, 16a affecting the operation feeling of the manual adjustment cylinder 7 are provided.
When the elastic force of the spring 16a is strong, the rotational force is transmitted to the cam plate 14 through the end face 14c, and when the elastic force of the spring 16a is weak, as shown in FIG. Is restricted by the elongated hole 13a, so that a rotational force acts on the ball 15a and the elongated hole 13a, and the cam plate 1
The automatic adjustment cylinder 5 is driven through the cam holder 4 and the cam holding plate 13. Then, when the driving force from the manual adjustment cylinder 7 is released, the manual adjustment cylinder 7 is pushed back until the ball 15a contacts the surfaces 12b and 14a under the elastic force from the spring 16a, and the clutch ring 12 The lock state is established, and manual adjustment or motor drive becomes possible. The same applies to the case where the motor drive and the manual operation are reversed.

When there are a plurality of clutch mechanism units,
In order to lock and release the clutch, the clearance between the release pin and the ball should be equal in the clockwise and counterclockwise directions when the manually operated cylinder is turned, or the elastic force of the spring should be weak enough to release the locked state.

Next, another embodiment of the clutch mechanism unit will be described with reference to FIG. FIG. 6 is a development view showing the clutch mechanism unit. In the figure, release pin 1
A pin holding plate 18b in which 7b is implanted is provided around the automatic adjustment cylinder 5 so as to be rotatable around a point O. The pin holding plate 18b is sandwiched by the manual adjustment cylinder 7 with a small gap so as to be rotatable. And the pin holding plate 1 when the manual adjustment cylinder 7 is turned clockwise.
Assuming that the contact point with 8b is t and the contact point when turned counterclockwise is t ′, the distance from O to t and t ′ is 1 and the distance from O to the release pin 17b is p, Depending on the distance,
The rotation angle of the manual adjustment cylinder and the release pin 17b around the optical axis for the automatic adjustment cylinder for locking and releasing can be set arbitrarily.

Similar effects can be obtained by making the following changes. For example, as for the cam member, in the embodiment, the cam plate and the cam holding plate are shown in a plane with respect to the optical axis direction, but may be formed in an arc shape with respect to the optical axis direction. Further, the cam shape may not be a straight line but may be a curve or the like. Further, it is possible to reverse the unevenness of the cam shape.
It is also possible to separate the clutch on the left and right. further,
The direction of the cam can be reversed even in the optical axis direction. Further, the ball may be a cylindrical roller, and the release pin may not be circular but may be rectangular or any other shape.

Further, the clutch mechanism unit can be driven by a hollow motor such as an annular vibration wave motor.

[0024]

As described above, according to the structure of the present invention, it is possible to provide an inexpensive and high-quality AF lens barrel that can be adjusted at all times without providing any special switching means in the manual adjustment of the AF lens. .

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a clutch mechanism unit employed in a lens barrel of the present invention.

FIG. 2 is an operation explanatory view of a clutch mechanism unit.

FIG. 3 is an operation explanatory view of a clutch mechanism unit.

FIG. 4 is an operation explanatory view of a clutch mechanism unit.

FIG. 5 is a sectional view of a lens barrel of the present invention equipped with a clutch mechanism unit.

FIG. 6 is a development view showing a clutch mechanism unit of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holding frame 2 Distance adjustment cylinder 3 Moving cylinder 4 Fixed cylinder 5 Automatic adjustment cylinder 6 Focusing lever 7 Manual adjustment cylinder 8 Motor 9 Reduction mechanism 10 Internal teeth 11 Clutch mechanism unit 12 Clutch ring 13 Cam holding plate 14 Cam plate 17 Release Pin 17b Release pin 18 Pin holding plate 18b Pin holding plate

Claims (2)

[Claims] 1. An automatic adjustment in which a motor is driven to move at least a part of a moving lens of an imaging optical system in an optical axis direction and a distance adjustment cylinder that enables focus adjustment is moved by a motor in a circumferential direction of the optical axis. A manual adjustment cylinder that is biased from the left and right to maintain a relative fixed position while having a small play angle to the left and right with respect to the cylinder and the automatic adjustment cylinder, and has a manual adjustment cylinder that is moved by manual rotation; In the middle of the drive connection system up to the adjustment cylinder, the drive connection system from the motor to the automatic adjustment tube is normally in a connected state, and the automatic focus adjustment operation can be performed. When a manual operation force is applied to the adjusting cylinder, the motor driving system is disengaged by the operating force, and in a lens barrel provided with a clutch mechanism capable of manually adjusting the movement of the distance adjusting cylinder, A lens barrel characterized in that a clutch mechanism having a pair of movements in the left and right directions is unitized and one or more clutch mechanisms are provided in the circumferential direction of the optical axis. 2. A cam having a cylindrical driving interlocking member connected to the driving side and having a groove on the circumference, a driven interlocking member connected to the driven side abutting on the driving interlocking member, and a symmetrical inclined surface. A clutch holding plate to which the cam member is fixed is provided around the driven interlocking member so that the member is located in the groove of the drive interlocking member, and an end face of the groove formed on the drive interlocking member and the cam member are formed. Rollable balls or rollers are pressed against the wedge-shaped gap formed between them by the bias of a spring, and the drive interlocking member and the cam member are always kept in a locked state to connect the drive side and the driven side. And a connection releasing mechanism in which a release pin extending from the manual adjustment cylinder is inserted into a gap between the left and right balls or rollers at the apexes of both inclined surfaces of the cam member. 2. The lens barrel according to 1.