JP3007736B2 - Rotary feeding mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary feeding mechanism that feeds one of a pair of annular bodies screwed via a multi-thread screw (helicoid) while rotating the same through a gear mechanism.

[0002]

2. Description of the Related Art In a lens barrel, for example, a movable (inner) annular body is screwed to a fixed (outer) annular body via a multi-thread screw, and the movable annular body is rotated to provide light. A number of mechanisms that extend in the axial direction are employed. In the zoom compact camera, a gear is provided on the outer periphery of the movable ring to drive the movable ring, and the gear is meshed with a pinion driven by a motor.

In this rotary feeding mechanism, it is necessary to provide both a multi-thread screw and a gear on the outer periphery of the movable annular body. Conventionally, in order to shorten the axial length of the movable annular body, this multi-thread screw and gear were cut off a part of the multi-thread screw, and a gear inclined in the same direction as the screw thread was provided in the cut part. Was formed. Thus, if the multi-thread screw and the gear are mixed at the same axial position, the axial length of the movable annular body can be reduced as compared with the case where both are provided at different axial positions.

However, in this rotary feeding mechanism, it has been found that the following problem arises when the moving amount of the movable annular body is further increased. In other words, to increase the feeding amount, increase the number of gear teeth or increase the gear width,
It is necessary to increase the axial length of the pinion that meshes with the pinion. However, increasing the number of teeth of the gear means that the gear extends obliquely in the direction of the multi-thread, that is, the axial length of the movable annular body is increased. In addition, when the width of the gear is increased, the ratio in the circumferential direction in which the multi-threaded screw is to be formed is reduced by that amount, and as a result, the movable annular body falls down and rattles.

In order to increase the zoom ratio in a zoom lens of a camera which is required to be as small as possible, it is necessary to provide a sufficient amount of extension without causing the movable annular body to fall. Can't respond to request.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary feeding mechanism which can increase a feeding amount of a movable annular body (an inner annular body) and is hard to fall down, based on the above awareness of the problem with the rotary feeding mechanism. With the goal.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an inner annular member and an outer annular member which are screwed through a multi-threaded male screw and a multi-threaded female screw; And a pinion that meshes with the gear and rotates the inner annular body relative to the outer annular body, wherein a plurality of the gears are formed on the outer periphery of the inner annular body. In addition, at least one external thread is formed between the plurality of gears, and an internal thread that is screwed with the external thread is formed on the inner periphery of the outer annular body, and the pinion is extended from the inner annular body. Irrespective of the position, meshed with at least one gear of the plurality of gears.

According to this configuration, a sufficient amount of feeding of the inner annular body can be ensured by the relationship between the plurality of gears and the pinion that meshes with any one of the plurality of gears. The internal thread can be prevented from falling down by the intermeshing multi-threaded screws that are also present between the and the escape groove.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
First, with reference to FIGS. 3 to 5, an example of a zoom lens barrel provided with a rotary feeding mechanism according to the present invention will be described.

Fixed lens barrel 11 integrated with camera body
, A helicoid ring (outer annular body) 12 is fixed, and a multi-threaded male screw 10 a formed on the outer peripheral surface of the cam ring (inner annular body) 10 is screwed to the multi-thread female screw 12 a of the helicoid ring 12. . Inside the cam ring 10, have multi-start internal thread 10b and inner cam groove 10c is formed, Tajomesu
The front lens barrel (male helicoid body) 13 is provided in the screw 10b.
Male thread 13a is screwed. A rectilinear guide plate 14 is located at the rear end of the cam ring 10, and a radial projection 14 a of the rectilinear guide plate 14 is fitted in a rectilinear guide groove 11 a formed in the fixed lens barrel 11. A rectilinear guide ring 15 is fixed to the rectilinear guide plate 14, and the cam ring 10 is rotatable with respect to the rectilinear guide ring 15.

A shutter holding frame 13b to which a rear end portion of an annular shutter unit 16 is fixed is fixed to the front lens barrel 13, and a helicoid ring 17 integrally provided on an inner peripheral portion of the shutter unit 16 is fixed. , The front group lens frame 18 holding the front group lens L1 is screwed. The shutter unit 16 has its drive pin 16a engaged with a driven pin 18a integrated with the front lens frame 18. Drive pin 1
As is well known, 6a is driven to rotate by an angle corresponding to the distance measurement signal from the distance measurement device, and this rotation is transmitted to the front group lens frame 18 via the driven pin 18a, and the front group lens frame 18 is rotated.
The (front lens L1) moves in the optical axis direction while rotating, and focusing is performed. Further, the shutter unit 16 opens and closes the shutter blade 16b according to the luminance signal of the subject.

Rear lens group frame 1 supporting rear lens group L2
9 has a cam pin 19a projecting in the radial direction, and this cam pin 19a is fitted in the cam groove 10c formed on the inner surface of the cam ring 10. The rear group lens frame 19 and the shutter holding frame 13b are connected to the straight guide ring 15
The straight guide is formed by the straight guide surface formed at the center. FIG. 5 shows a rectilinear guide surface 15a of the rectilinear guide ring 15 and a rectilinear guide surface 19b of the rear lens group frame 19, which are engaged with each other.

The cam pin 19a of the rear lens group frame 19 is provided with a recess 13 formed in the rear end face of the front lens barrel 13 during assembly.
b. This is a multi-line on the outer circumference of the front lens barrel 13.
When the male screw 13a is screwed into the multi-thread female screw 10b of the cam ring 10, the cam pin 19a is simultaneously engaged with the inner cam groove 10c.
It is a structure for fitting in. After assembly, the front lens barrel 13 is turned by the rotation of the cam ring 10 so that the multi-threaded screws 10b and 13a
, The rear lens frame 19 follows the cam groove 10c and moves independently in the optical axis direction.

That is, the zoom lens barrel having the above structure is
When the cam ring 10 is rotationally driven, the multi-start male screw 10a and the multi-start
The cam ring 10 itself moves in the optical axis direction according to the relationship of the female screw 12a. At the same time, the multi-start female screw 10b and the multi-start male screw 1
3a and the linear guide mechanism of the shutter holding frame 13b and the linear guide ring 15, the front lens barrel 13
The (front lens L1) moves straight in the optical axis direction. When the cam ring 10 rotates, the rear group lens is formed by the relationship between the cam groove 10c on the inner surface of the cam ring 10 and the cam pin 19a provided on the rear group lens frame 19, and the rectilinear guide mechanism of the rear group lens frame 19 and the rectilinear guide ring 15. The frame 19 (the rear lens group L2) moves in the optical axis direction, and zooming is performed.

The present invention relates to, for example, a helicoid ring (outer ring) 12 in a zoom lens barrel having the above-described structure.
And a cam ring (inside annular body) 10 and a rotation drive mechanism of the cam ring 10. Cam ring 1
In FIG. 0, as shown in the developed view of FIG. 1 and FIG. 5, a multi- threaded external thread 10a and a plurality of (three in this embodiment) mutually parallel gears 10d are formed at the rear portion. I have. The gear 10d is formed of a spur gear whose teeth are parallel to the axis of the cam ring 10, and is inclined in the same direction as the direction of the ridge of the multi- threaded external thread 10a.
A single thread 10a ' of the external thread 10a is formed. In other words, the multi- threaded external thread 10a has one or more threads 10a 'cut off at a part in the circumferential direction.
Is, the gear 10d is provided in the cutting portion. In this embodiment, the thread of the multi-threaded external thread 10a is formed every other thread.
Three cuts are made, and a gear 10d is provided in those cut portions . These multi-threaded male screw 10a and thread 10a '
And the formed length s of the gear 10d in the axial direction is the same.

On the other hand, as shown in FIG. 2, the helicoid ring 12 has a multi-threaded male screw 10 of the cam ring 10 on its inner surface.
a, the multi-threaded female screw 12a and the single thread 12 corresponding to the single thread 10a 'and the three gears 10d, respectively.
a 'and the escape groove 12c are formed. That is, threads 10a 'with the thread 12a' is interdigitate gear 10d is multi-start external thread 10a and the multiple-start internal thread 12
When the cam ring 10 rotates in accordance with the screw thread a and the thread 10a 'and the thread 12a', the cam ring 10 moves in the clearance groove 12c in a non-contact manner.

A notch 12d is formed in the helicoid ring 12, and a pinion 20 located in the notch 12d is formed.
Are engaged with the gear 10d. This pinion 20
Has an axial length capable of meshing with the three gears 10d at the same time, but at the forward moving end and the rearward moving end of the cam ring 10, it meshes only with the rearmost and front gears 10d, respectively. The pinion 20 is rotatably supported by a fixed portion (not shown), is located at a fixed position in the notch 12 d, and is rotationally driven by a motor 21.

In FIG. 1, two pinions 20 are drawn at different positions to show the meshing relationship between the pinion 20 and the gear 10d at the forward end and the backward end of the cam ring 10. Actually, the pinion 20 does not move, and the cam ring 10 moves in the optical axis direction.

Also, in the above embodiment, Tajo Yune
The maximum outer diameter (height from the axis center to the peak) of 10a is D
1. The tooth height of the multi-threaded male screw 10a (the height from the valley bottom to the peak)
D) from the cylindrical surface connecting the peaks of the multi-threaded male screw 10a
The tooth height of the gear 10d up to the tooth tip is d2, and the clearance groove 12c is
Assuming that the thickness of the bottom is t, the thickness T1 of the helicoid 12
Is a T1 = d1 + d2 + t.

Accordingly, when the pinion 20 is rotationally driven via the motor 21, the rotation is transmitted to the cam ring 10 via the gear 10d. Then, according to the meshing of the multi-start male screw 10a (thread 10a ') and the multi-start female screw 12a (thread 12a'), the cam ring 1
0 rotates in the optical axis direction while rotating, and zooming is performed.

When rotating the cam ring 10, the pinion 20 always meshes with any one of the three gears 10d, and the thread 10a 'and the thread 12a.
The meshing of a 'is maintained. Of course, multi-threaded male screw 10a and multi- threaded
Since the meshing of the female screw 12a is also maintained, the helicoid ring 1
2, the cam ring 10 does not fall.

FIGS. 6 and 7 show two comparative examples for obtaining the same feed amount of the cam ring 10 as in the embodiment of the present invention without forming three gears 10d. FIG. 6 shows an example in which a gear 10d 'having the same width as the gear 10d of the embodiment of the present invention is formed as a single line, and FIG. 7 shows a wide gear having the same axial length s as the gear 10d of the embodiment of the present invention. 10d ″ is formed. In the comparative example of FIG. 6, the installation length of the gear 10d ′ in the axial direction, that is, the cam ring 1 is formed.
0 becomes longer, and in the comparative example of FIG. 7, the installation length of the multi-threaded male screw 10 a in the circumferential direction becomes shorter, and the cam ring 10 easily falls down.

The zoom lens barrel shown in FIGS. 3 to 5 is an example of a device to which the rotary feeding mechanism of the present invention can be applied. INDUSTRIAL APPLICABILITY The present invention can be widely applied to a rotation / extension mechanism of another zoom lens barrel or a rotation / extension mechanism other than the zoom lens barrel.

[0024]

As described above, according to the rotary feeding mechanism of the present invention, the feeding of the inner annular body which is screwed to the outer annular body via the multi-threaded screw and driven to rotate via the gear formed on the outer peripheral surface. The amount can be increased, and the fall can be prevented.

[Brief description of the drawings]

FIG. 1 is a development view of an inner annular body (cam ring) showing an embodiment of a rotary feeding mechanism according to the present invention.

FIG. 2 is a cross-sectional view of a state where the inner annular member and the outer annular member are engaged with each other.

FIG. 3 is a cross-sectional view showing an example of a zoom lens barrel to which the rotary feeding mechanism according to the present invention can be applied.

FIG. 4 is a sectional view of a main part of the zoom lens barrel of FIG. 3;

FIG. 5 is an exploded perspective view of a main part of the zoom lens barrel in FIG. 3;

FIG. 6 is a development view corresponding to FIG. 1 and shown as a comparative example.

FIG. 7 is a development view corresponding to FIG. 1 and shown as another comparative example.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 cam ring (inner ring) 10 a multi-threaded external thread 10 a ′ thread 10 d gear 12 helicoid ring (outer ring) 12 a multi-threaded internal thread 12 a ′ thread 12 c relief groove 12 d notch 20 pinion

Claims (3)

(57) [Claims] 1. An inner annular body and an outer annular body screwed via a multi-threaded male screw and a multi-threaded female screw; a gear formed on the outer periphery of the inner annular body so as to be inclined in the same direction as the multi-threaded male screw ; And a pinion that meshes with the gear and rotates the inner annular body relative to the outer annular body; a plurality of the gears are formed on the outer circumference of the inner annular body, At least one gear between multiple gears
Female screw which is screwed with the male screw on the inner circumference of the outer annular body
And the pinion, regardless of the extended position of the inner annular body,
Rotating feeding mechanism, characterized in that, that engage in at least one strip of a gear of said plural rows of gears. 2. The method according to claim 1, wherein the pinion is
To prevent interference with the external thread formed between the gears,
The gear tip circle diameter is larger than the outer diameter of the male screw.
Rotating feed mechanism. 3. The outer annular member according to claim 1, wherein
An escape groove is formed around the circumference to allow the gear to pass through.
A female screw is formed in the groove to engage with the male screw of the inner ring.
A rotary feeding mechanism.