JP3473773B2 - Zoom lens barrel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel for a camera.

[0002]

2. Description of the Related Art The zoom ratio of this type of zoom lens barrel has recently been increased, and the lens barrel has become complicated,
There are problems such as deterioration of assemblability, deterioration of optical performance, and difficulty in repairing when a failure occurs.

FIG. 12 is a schematic view of a conventional four-group zoom. In FIG. 12, the first-group lens 61 has a first-group support frame 65.
It is supported by -1. The second group lens 62 is supported by the second group support frame 65-2, and the second group pin 67 extending in the radial direction from the second group support frame 65-2 is fitted into the cam portion 69 of the 1-2 group cam ring 68. Moreover, the rotation is stopped by being guided by the straight-ahead key 611 (hereinafter, all the straight-ahead keys are shown by diagonal lines) of the fixed cylinder 610. Therefore, the second group support frame 65-2
The first-second group cam ring 68 rotates about the optical axis to move back and forth in the optical axis direction.

The first-second group cam ring 68 is a first-second group gear 6
8a is provided along the outer periphery at the front end thereof.
The pinion 612 meshing with the second group gear 68a is driven by a drive source (not shown) to rotate.

A first-group pin 613 extending in the radial direction is also provided at the rear end of the first-group support frame 65-1. The first-group pin 613 is formed on the cam surface 615 of the first-second group cam ring 68. Since the first-second group cam ring 68 is rotated, the first-second group cam ring 68 rotates in the optical axis direction as the second group supporting frame 65-2 is guided and is prevented from rotating by being guided by the straight-movement key 614 of the fixed barrel 610. Move back and forth.

Since the second group pin 67 and the first group support frame 65-1 are not restricted in the optical axis direction by the straight-movement key 616, they can be driven independently of each other in the optical axis direction.

A focus pin 617 is provided at the rear end of the first-second group cam ring 68. The tip 617a of the focus pin 617 is inserted into the circumferential groove 68d of the first-second group cam ring 68, and the first-second group cam ring 68 is restricted in movement in the optical axis direction but not restricted in rotation direction. .

The focus pin 617 is a fixed barrel 610.
Since it is guided by the straight-moving key 631 of No. 1, it does not rotate about the optical axis, but the groove 68d described above allows the first-second group cam ring 6
The rotation of 8 is not restricted. The focus pin 617 is fitted on the cam surface 620 of the focus cam ring 618,
When the focus cam ring 618 rotates, it moves back and forth in the optical axis direction, and accordingly, the 1-2 group cam ring 68 also moves back and forth in the optical axis direction, so that the first group lens 61 and the second group lens 62 are simultaneously moved. Adjust the focus by extending and retracting.

The focus cam ring 618 is the fixed barrel 61.
0 is fitted on the outer periphery of the fixed cylinder 610, and the movement in the thrust direction is restricted by the flange 610a of the fixed cylinder 610 and the thrust receiving ring 619 screwed to the fixed cylinder. The focus cam ring 618 is driven by a drive source (not shown) via a gear 618a provided at the rear end.

The pin 6 driven into the first-second group cam ring 68.
8c is fitted in the straight advance key 622 of the 3-4 group cam ring 621. Therefore, the 3-4 group cam ring 621 rotates together with the 1-2 group cam ring 68.

In this case, although the mutual movements in the optical axis direction are not restricted, the first-second group cam ring 68 is the focus cam ring 61.
Driven by 8. The third-fourth group cam ring 621 is a fixed cylinder 610.
The rear end portion 610b is bayonet-coupled and the rotation direction is not restricted, but the movement in the optical axis direction is restricted. The third group lens 63 is supported by the third group supporting frame 623, and the third group pin 624 extending in the radial direction from the third group supporting frame 623 is a 3-4 group cam ring 6.
21 is fitted into the cam surface 626, is engaged with the straight advance key 625 of the fixed barrel 610, and is guided in the optical axis direction.

The fourth group lens 64 is supported by the fourth group support frame 627, and the fourth group pin 628 extending radially from the fourth group support frame 627 is fitted into the cam surface 629 of the 3-4 group cam ring 621. The linearly moving key 625 of the fixed barrel 610 is engaged and guided in the optical axis direction. Therefore, the third-fourth group cam ring 621
When is rotated, the third lens group 63 and the fourth lens group 64 move back and forth in the optical axis direction.

[0013]

However, the conventional zoom lens barrel as described above has the following problems.

Assembling Problem The fixed barrel 610 is long in the optical axis direction, and the third group support plates 623, 4 are provided.
It is difficult to assemble the group support frame 627 into the inside, and it takes time to assemble.

The first group pin 613, the second group pin 67, the third group pin 624, the fourth group pin 628, and the focus pin 617.
All of the straight keys 614, 611, 616, 625, 6
It was a complicated task to match the phase of 31.

Problems of Optical Adjustment In a multi-group lens structure such as a zoom lens of four groups consisting of the first group lens 61 to the fourth group lens 64, lens tilt for optical adjustment and decentering adjustment are one of them. It is not necessary to use only one group lens, but it becomes necessary to adjust at least two group lenses.

However, if two group lenses are moved for adjustment while all the group lenses are assembled, it is difficult to understand the point of the adjustment vest. This is because the two group lenses for adjustment interfere with each other to change the optical characteristics, and after adjusting one of the group lenses to the best, it is desired to adjust the next group lens. However, if all the group lenses are assembled as shown in FIG. 12, it cannot be confirmed that “either group lens is adjusted to the best”.

Maintenance Problems When a problem occurs during assembly or after shipping, for example, when the diaphragm 630 in FIG. 12 fails, disassembling the lens barrel is difficult.

An object of the present invention is to obtain a zoom lens barrel which solves the above problems.

[0020]

According to another aspect of the present invention, there is provided a zoom lens barrel having a lens group of a first lens group, a second lens group, a third lens group, and a fourth lens group in order from a subject side. A first fixed barrel for holding the first group lens and the second group lens, and a cam for rotating the first group barrel and the second group lens while rotating with respect to the first fixed barrel. The first cam barrel having the above, the second fixed barrel for holding the third group lens and the fourth group lens, and the third fixed barrel for rotating with respect to the second fixed barrel.
A second cam barrel having a cam for moving the group lens and the fourth group lens, wherein the first fixed barrel is the second
It is characterized in that it is fixed to the fixed cylinder. This facilitates assembly, optical adjustment, and maintenance.

According to a second aspect of the invention, in the first aspect of the invention, the first fixed barrel is fixed to the second fixed barrel by screwing.

A zoom lens barrel according to a third aspect of the present invention is a zoom lens barrel having a first group lens, a second group lens, a third group lens, and a fourth group lens in this order from the subject side, and the fourth group lens is supported. And a fourth group support frame having a fourth group pin extending in the radial direction and the outer diameter of the fourth group support frame,
A third group support frame having a third group pin that supports the group lens and extends in the radial direction, and is fitted to the outer diameter of the third group support frame to guide the fourth group pin and the third group pin only in the optical axis direction. The 3-4 group fixed barrel having a straight-moving key and the outer diameter of the 3-4 group fixed barrel fitted to the 3-4 group fixed barrel are restricted in movement in the optical axis direction and rotated around the optical axis. The 3-4 group cam ring having a cam surface for moving the 4 group pin and the 3 group in the optical axis direction, and the 2 group supporting frame having the 2 group pin for supporting the 2 group lens and extending in the radial direction A first group support frame fitted to the outer diameter of the second group support frame, supporting the first group lens and having a first group pin extending in the radial direction, and fitted to the outer diameter of the first group support frame. It has a cam surface that moves the second group pin and the first group pin in the optical axis direction by rotating around the optical axis, and extends in the optical axis direction with the 3-4 group cam ring. Keyway and key combined with the to 3-
The rotation around the optical axis of the fourth group cam ring is transmitted,
Movement is not restricted in the optical axis direction with respect to the group cam ring 1-2
A group cam ring, a first-second group ring having a focus pin that is restricted in movement in the optical axis direction with respect to the first-second group cam ring and extends in the radial direction, and the outside of the first-second group cam ring. A first-second group fixed barrel having a straight-movement key for fitting the second group pin, the first group pin, and the focus pin only in the optical axis direction, and the outer diameter of the first-second group fixed barrel And a focus cam ring having a cam surface for moving the focus pin in the optical axis direction by rotating around the optical axis. This makes assembly easy, optical adjustment,
Easy maintenance.

[0023]

[0024]

[0025]

[0026]

[0027]

Embodiments of the present invention will now be described with reference to the drawings. 3 to 5 are exploded perspective views showing the configuration of the fourth group zoom lens barrel unit.

Second-group unit (first barrel unit) The second-group supporting frame 48 is fitted into the inner diameter of the first-group supporting frame 43, and the first-group supporting frame 43 is fitted into the inner diameter of the first-second group cam ring 49. To fit. The first-second group cam ring 49 has first-group cams 425 (three places) and second-group cams 426 (three places) from wide to tele.
It is provided at an angle of 0 degree. Each of the cams has a taper cam configuration having an angle of 30 degrees with respect to the radial direction in relation to die cutting.

The first-second group cam ring 49 includes a first-second group ring 4
10 inner diameter protrusions 427 (3 places) are fitted with bayonet,
The first-second group ring 410 is supported by the first-second group cam ring 49 so as to be rotatable around the optical axis. To prevent the bayonet fitting from slipping off, each pin to be described later is fastened to the lens barrel through each cam groove. The first-second group cam ring 49
Is fitted to the inner diameter of the first-second group fixed barrel 413, and the first-group support frame 4
3 includes a first group cam 425, a first group linear movement key 428 (1 part under cam, 3 places), a first group roller 44 (taper roller, 3 pieces), and a first group roller spring 4 for suppressing the first group roller 44.
5 (necessary because of taper cam, 3) 1st group pin composed of 1st group roller shaft 46 is attached, and the 1st-2nd group fixed cylinder 41
3 is attached so as to be movable only in the optical axis direction.

Similarly, the second group support frame 48 has a second group cam 426,
The second group straight-moving key 4 formed on the first-second group fixed barrel 413
2nd group roller 44, 2nd group roller spring 4 through 29 (3 places)
It is fastened to the second group pin composed of the fifth and second group roller shafts 47 (3 places), and is attached to the first-second group fixed barrel 413 so as to be movable only in the optical axis direction. Further, the auto barrier ring 414 is adhesively fixed to the first-second lens group fixed cylinder 413, and the focus cam ring 415 is fitted to the outer diameter.

Then, the focus roller 411 (3) through the focus cam 431 (three positions having a retractable area and a cam in the focus area, which will be described later) formed on the focus cam ring 415 and the focus linear movement key 430 (three locations).
And the focus pin composed of the focus roller shafts 412 (three) are fastened to the first-second group ring 410, and the first-second group cam ring 49 moves in the optical axis direction with respect to the first-second group fixed barrel 413. It is movably movable and rotatable about the optical axis (because the first-second group cam ring 49 and the first-second group ring 410 rotate relative to each other).

FIG. 1 is a sectional view of the lens barrel unit in the assembled state. When the second-group cam ring 49 is extended to move from the retracted state (a) to the photographing state (e), the first group is moved. The lens and the second group lens are extended. Therefore, the focus cam 431 has the shape shown in FIG.

In FIG. 2, the focus cam 431 is composed of an area (standby) area A and a focus area B which are extended from the collapsed state, and when the camera main switch is turned on, the focus cam ring 415 rotates in the direction of arrow 432 and the first-second group ring. The first-second lens group cam ring 49 is extended in the direction of arrow 433 through the focus roller 411 attached to 410 to be a photographing possible area. After that, further focus cam ring 415
The first group lens 61 and the second group lens 62
Move the lens back and forth in the optical axis direction to adjust the focus.

3-4 group unit (second lens barrel unit) In FIG. 4, the 4th-group support frame 41 is sandwiched by the 3-4th group spring 418 on the 3rd group support frame 416 in which the 3rd group lens is thermally crimped.
9 fits inside. The 3-4 group cam ring 423 is fitted to the groove 434 of the 3-4 group fixed cylinder 424 by the inner projection 435 (three places) and the bayonet outer diameter, so that the 3-4 group cam ring 423 is the 3-4 group fixed cylinder. Only rotation about the optical axis is performed on 424. The groove 434a is a guide groove of the inner projection 423a for allowing the 3-4 group cam ring 423 to be bayonet-coupled to the 3-4 group fixed cylinder 424 in a certain phase. It is provided along the outer periphery of the fourth group fixed cylinder 424 (3 places).

The third group support frame 416 is a third-fourth group fixed cylinder 424.
3-4 group cam 436 (3 places, straight cam), 3-4 group key groove 435 (3 places), 3rd group pin 417a and 4th group pin 417b are respectively 3rd group support frame 416, It is fastened to the fourth group support frame 419. Since the third group support frame 416 and the fourth group support frame 419 repel each other by the 3-4 group spring 418, the third group pin 417a attached to the third group support frame 416 is the front side 436a of the 3-4 group cam 436.
The fourth-group pin 417a attached to the fourth-group support frame 419 is pressed against the rear side 436b of the third-fourth group cam 436. This eliminates any play between the third and fourth lens groups and the cam.

When the third-fourth group cam 436 is rotated, the front side 436a and the rear side 43 of the third-fourth group cam 436 are rotated.
Following the cam shape of 6b, the third group support frame 416 and the fourth group support frame 419 are extended and retracted in the optical axis direction. The fourth group lens barrel 420 is attached to the fourth group supporting frame 419 with the fourth group lens barrel stop screw 422 through the fourth group lens barrel spring washer 421 (three pieces). Since the screw through hole is a fool hole, the fourth group lens barrel 420 can move in a plane perpendicular to the optical axis with respect to the fourth group support frame 419 when the fourth group lens barrel stop screw 422 is weakly tightened. Then, when the 3-4 group unit is completed, the 4th group lens barrel 420 is eccentrically adjusted with respect to the 3rd group lens, and the 4th group lens barrel stop screw 422 is tightened.

First-second group unit (first lens barrel unit)
And attachment of the 3-4 group unit (second lens barrel unit) 1st unit extending from the 2nd group lens barrel 48 in the 1-2 group unit state
Of the flexure 438 of FIG. 3 is soldered to the second flexure 440 attached to the shutter unit 439 with the comb teeth 438a, and the second flexure 440 is passed through the inner diameter hole of the third group support frame 416 so that the shutter unit 439 is supported by the third group support frame. Screw to 416 (3 places).

Next, the 3-4 group unit to which the shutter unit 439 is attached is put into the 1-2 group unit. Put the 3-4 group unit inside the 2nd lens barrel 48,
-1-2 in the keyway 441 (3 places) of the 4th group cam ring 423
The inner diameter protrusion 49a of the group cam ring 49 is fitted. As a result, the first-second group cam ring 49 rotates in accordance with the rotation of the third-fourth group cam ring 423.

To connect the 3-4 group unit and the 1-2 group unit, the 3-4 group fixed cylinder 424 is attached to the thick surface connection surface of the 1-2 group fixed cylinder 413 with the screw 442a (coupling means). Done in. Further, the first-second group fixed barrel is screwed together with the radial screw 442b integrally with the third-fourth group fixed barrel.

At this time, the optical axis direction projections 443 (4 places) of the 3-4 group fixed barrel 424 receive the focus cam ring 415, and the focus cam ring 415 is attached to the 1-2 group fixed barrel 41.
It is sandwiched between the flange portion 413a of No. 3 and the protrusion 443, and its movement in the optical axis direction is restricted, and it is movable only in the rotational direction.

Finally, the first group lens 61 is attached to the first group support frame 43.
The first group lens barrel, which has been heat-crimped, is fitted into the inner diameter, but when the first group lens barrel is rotated around the optical axis, the taper 44
3 (3 places) ride on the projections 444 (3 places) of the 1-group support frame, and the 1-group barrel tilts with respect to the optical axis. Then, the rotation around the optical axis of the first group lens barrel is adjusted to perform optical adjustment in the first group, and finally the first group holding ring 41 is screwed into the first group support frame 43 to complete the assembly of the lens barrel unit. To do.

The inner circumference of the first-second group cam ring 49 and the outer circumference of the third-fourth group cam ring 423 are not fitted but have a desired clearance, and the first-second group unit and the third-fourth group. It absorbs the mounting error when mounting the unit.

Description of the operation of the lens barrel unit Collapsed → Standby camera When the main switch is turned on, the first group lens 61,
The second group lens 62 is extended to enter a photographing ready state (standby). The operation at this time will be described.

When the camera main switch is turned on, the focus driving force of the gear chassis unit 35 shown in FIG. 3 is applied to the pinion 525 and the gear 4 of the focus cam ring 415 shown in FIG.
2 through the focus cam ring 415 through the arrow 4 in FIG.
Drive in 32 directions. And more than the area A section of FIG.
The first-second group cam ring 68 is extended to bring it into a standby state.

Focus drive focus is adjusted by moving the first lens group 61 and the second lens group 62 back and forth in the optical axis direction. The drive method is performed by rotating the focus cam ring 415 (section B in FIG. 2). The drive amount is controlled by reading the gear rotation amount with a pulse encoder (incremental type using the photo interrupter 511) attached to the gear chassis unit 35.

Focus drive control is shown in FIG.
The front end of the focus switch 36, which is attached to the flange portion of the fourth group fixed barrel 424 via the focus switch seat 36a, is in contact with the cam lift 415a of the focus cam ring 415.
At the 15th position, the focus switch 36 separates from the cam lift and is turned off. When the focus cam ring 415 is driven even a little from the retracted state, the focus switch 36 rides on the cam lift and turns on. Then, in the area A section, the focus switch 36 is separated from the cam lift and turned off again, and the area becomes the photographic possible area (stand).

At this point, counting of encoder pulses is started. After that, the focus cam ring 415 is driven by the amount of the lens extension pulse based on the distance measurement to perform the focus adjustment. In other words, one focus switch 36 can detect the collapse and the focus, and the size can be reduced.

Zoom drive Zoom is performed by moving all the groups back and forth in the optical axis direction. When a zoom switch on the exterior of the camera (not shown) is operated, the zoom driving force of the gear chassis unit 35 drives the 3-4 group cam ring 423 via the gear 446 of the 3-4 group cam ring from the pinion 526. Then, the third group lens 63 and the fourth group lens 64 are extended along the cam shape of the third-fourth group cam 436. Further, the rotational force is transmitted to the 1-2 group cam ring 49 via the key groove 441 of the 3-4 group cam ring 423, and the 1st group cam 4
25, the first group lens 6 along the cam shape of the second group cam 426.
The first and second group lenses 62 are extended.

Similarly to the focus drive, 3-in FIG.
The zoom switch seat 37 is attached to the flange of the fourth group fixed barrel 424.
The tip of the zoom switch 37 bonded via a is 3
The fourth-group cam ring 423 is in contact with the protrusion 446a, and when it is slightly retracted from the wide end, the protrusion comes into contact with the tip end of the zoom switch 37 to turn on the zoom switch 37.

Then, when the zoom switch 37 is driven to the wide end and turned off, counting of encoder pulses for zooming is started in the same manner as in focus driving, and the amount of rotation of the zoom gear is monitored. The current zoom position is read according to the amount of the encoder pulse, and the focus dull sensitivity at that zoom position is extracted and used for focus control.

In this embodiment, as described above, firstly, 1-2
The group unit (first barrel unit) and the 3-4 group unit (second barrel unit) can be easily attached and detached by turning the screws 442a and 442b. As a result, i) Assembling property is improved: 1 by assembling the first and second lens groups
Since the second-group unit and the third-fourth unit including the third-group and fourth-group lenses can be separately assembled, workability is good, and the construction of each unit is not so complicated, so that no skill is required for the work. ii) Optical adjustment is simple and easy.

In the 3-4 group unit state, the eccentricity of the 4 group lens 64 is accurately adjusted by a known method using a projector or the like, and the screw 422 is tightened to fix the 4 group lens 64. Is absorbed by adjusting the inclination of the first group lens 61, and the first group holding ring is tightened. 2 like this
When the optical adjustment is performed using one lens, the four-group lens can be adjusted individually, so that there is no adjustment interference between the two lenses as described above, and the adjustment is easy. iii) Maintenance is easy.

Even if a problem occurs in the lens barrel, it can be easily disassembled and readjusted because each unit has a separate unit.

Conventionally, there has been a situation in which all the lens barrels are replaced, but it is sufficient to replace each unit.

Even if a problem occurs in the shutter unit 439, the shutter unit 439 is exposed only by removing the first-second group unit, so that adjustment and replacement are easy. Note that this configuration is effective not only when the shutter unit is attached to the third group, but also when other means such as a diaphragm means is attached.

In the zoom lens barrel of the present invention, the second group lens is independently driven and controlled in two directions perpendicular to the optical axis. This is to drive the second group in that direction to decenter the optical axis, and to base the amount of decentering on the amount of camera shake (detected by the camera shake detection sensor) applied to the camera for image stabilization.

For that purpose, a two-group lens drive and control structure is provided, but with the configuration of FIG. 1, the second-group unit is removed when the second-group failure occurs, and the third-fourth group unit is left as it is. Can be replaced, and the first lens group is removed (1
The two groups can be adjusted and checked only by loosening the group pressing ring 41, and the maintenance is easy.

In the zoom lens barrel of the present invention, the hole 424a in the rear end flange portion of the 3-4 group fixed barrel 424, which is the core of the 3-4 group unit (second barrel unit), is smooth around the rear hole. It has a coupling surface. It can be coupled to a camera body (not shown) having a film aperture surface by utilizing 4 places and 1 place invisible in FIG. 1. Here, the second lens barrel unit is attached to the camera body. Describe the reason for fixing.

In the case of a multi-group zoom lens, mounting accuracy is often strictly required for the rear lens group. Also in the zoom lens barrel of the present invention, the tilt of the first group lens can be adjusted, and the second group lens is designed to prevent deterioration of optical performance even if moved in the optical axis direction for vibration isolation. Both the group lens and the second group lens move in the optical axis direction by focusing. Therefore, the mounting accuracy is not so severe as compared with the third group lens and the fourth group lens.

First-second group unit (first lens barrel unit)
If the 3-4 group unit is attached to the camera and the 1-2 group unit is fixed to the camera body, the camera body and 1-2
Mounting error of group unit, 1-2 group unit and 3-
Both of the mounting errors of the 4th group unit occur as mounting errors of the 3rd group lens and the 4th group lens which are severe in accuracy from the film surface. Therefore, the 3-4 group unit is directly fixed to the camera body to reduce the mounting error of the 3 group lens and the 4 group lens.

The gear chassis unit 35 shown in FIG.
It is screwed to the flange portion of the group fixing cylinder 424 with a screw 35a. This is because when the gear chassis unit 35 is fixed to the camera body and the driving force is transmitted to the third-fourth group cam ring 423 and the focus cam ring 415, each pinion 525, 5
The reaction force between the gear 26 and the teeth 446 and 445 (generated by the relationship between the driving force and the lens barrel load) causes the gear chassis unit 35 to move.
And the third-fourth group cam ring 423 is lifted.
That is, backlash occurs between the camera body and the 3-4 group unit, and the optical performance is deteriorated.

However, if the 3-4 group unit and the gear chassis unit 35 are screwed and the 3-4 group unit is fixed to the camera body, there is no play between the 3-4 group unit and the gear chassis unit 35 (screw). Since it is screwed by 35a), a reaction force due to the driving force does not occur between the camera body and the 3-4 group unit, so that there is no play and the optical performance is not deteriorated.

In the zoom driving, when the zoom load becomes extremely heavy (for example, the zoom driving is performed while suppressing the lens barrel in the optical axis direction), the driving force of the motor causes distortion of each lens. This can be easily understood because each cam surface cannot push out the pins of each group even if each cam ring rotates.

Even if the distortion is slight, the optical performance is affected by a lens having severe mounting accuracy such as a third group lens and a fourth group lens. Therefore, in the zoom lens barrel of the present invention, when the zoom load becomes large,
The driving force does not slip and is not transmitted to the lens barrel.

Next, the slip structure will be described as a structure of the gear chassis unit 35. In the gear chassis unit configuration diagram of FIG. 5, when the unit is further subdivided, it is divided into i) a planetary operation speed reduction unit, ii) a slip unit, and each gear.

Planetary operation deceleration unit The planetary unit holder 57 and the planetary unit pulse shaft 56 sandwich (fit) a pair of planetary unit planetary gears 58,
Push it into the planetary unit case 51 or the unit case 52. Next, the planetary unit output gear 55 is put on and the planetary unit lid 53 or the planetary unit lid 54 is attached.

The planetary unit pinion gear 59 is press-fitted into the shaft of the planetary unit motor 512, and the claws 51b and 52b of the planetary unit case 51 or the planetary unit case 52 are engaged and fixed to the recess 512a of the terminal portion of the planetary unit motor 512.

The completed unit is attached to the rear part of the gear chassis 51.
Then, the planetary unit pulse sheet is press-fitted and bonded to the planetary unit pulse shaft 56, and the planetary unit photo interrupter 51 is bonded to the gear chassis rear portion 518.
(Note that the circumferential projections 53a of the planet unit lids 53, 54,
54a is a paralleling guide for adhering the planetary unit pulse sheet 510 to the planetary unit pulse shaft 56,
It faces the planetary unit pulse sheet 510 at a slight interval. The convex portions 53a and 54a also serve as adhesive guides for the photo interrupter 511. The slip unit output shaft 515 has a slip spring 516 and a slip gear 51.
3, and slip collar 514 is D-cut fitted,
Stop with E-ring.

The transmission gear 521 and the transmission gear 522 are fitted to the shafts 518F and 518Z of the rear part 518 of the gear chassis to which the planetary speed reduction unit is attached, and the completed slip unit is also fitted. The output gear 52 is attached to the output shaft 524.
3 is D-cut fitted and fitted into the rear portion 518 of the gear chassis.

The front F519 of the gear chassis is fitted to the output shaft 524, and is attached to the rear portion 518 of the gear chassis (press-fitting of the mounting shaft).

The wide-end slip switch 37 is adhered to the front Z520 of the gear chassis and attached to the rear 518 of the gear chassis (each shaft is press-fitted).

The pinion gear 525 is D-cut fitted to the output shaft 524, and similarly, the pinion gear 52 is attached to the output shaft 515.
6 is D-cut fitted.

An ST gear parent 527 and an ST gear element 528 used for a flashing means described later are fitted into the shafts 518a and 518b of the gear chassis rear portion 518 (3-4 group fixed barrel 4).
24 will not come off.)

In FIG. 5, when slipping, the slip gear 513 rides on the cam of the slip collar 514 and pushes forward against the slip spring 516, the slip switch 37 is pushed when the slip gear 513 pushes out, and the switch is turned on. To turn on.

When the slip occurs, the relationship between the zoom-out amount and the pulse is changed, so that the entire lens barrel system is reset (collapsed) when the slip switch is turned on.

That is, when the load on the lens barrel becomes heavy and distortion is likely to occur in the mounting of each lens, slippage will not occur and distortion will not occur, and the slip switch 37 prohibits relieving, causing a failure in photographing due to an optical abnormality. In addition to preventing, the entire system is reset to eliminate accumulated errors due to slip.

A coil spring 451 is provided between the first-group support frame 43 and the second-group support frame 48 to generate a repulsive force in the optical axis direction.
Is included (as shown in FIG. 1, the first group support frame 43
It is sandwiched between the flange 43a of the above and the front end of the second group support frame 48). By the force of this coil spring 451, the first group lens 61, 2
Although the looseness of the group lens 62 is eliminated, another advantage is generated here.

The lead of the first-group cam 425 for zooming the first-second group cam ring 49 in FIG. 3 stands (1-2).
By the rotation of the group cam ring 49, the first group support frame 43 is largely moved in the optical axis direction), but the lead of the second group cam 426 is not standing. Therefore, if the coil spring 451 is inserted between them,
The same thing as when the first group support frame 43 is spring-biased to the fixed point (because the amount of zoom movement of the second group support frame 48 is small).
Then, the spring force becomes the rotational force of the first-second group cam ring 49 and the third-fourth group cam ring via the first group cam 425. Therefore 3-
The coil spring 451 makes it possible to eliminate backlash between the teeth 446 of the fourth group cam ring 423 and the pinion 526 during zooming.

Although not shown in FIG. 3, the first-second group ring 410 is also spring-biased in the optical axis direction with respect to the first-second group fixed barrel 413. This is because the first-second group ring 41 is moved by the cam 431 of the focus cam ring 415 during focusing.
0 is driven in the optical axis direction, and accordingly, the first-second group cam ring 4
9 is driven in the optical axis direction, the first-group support frame 43 and the second-group support frame 48 move in the optical axis direction at the same time, and focus adjustment is performed. However, the play between the focus roller 411 and the focus cam 431 is also in focus accuracy. Since it leads to deterioration, the first-second group ring 410 (correctly, the focus roller 411) is spring-biased from the first-second group fixed barrel 413 in the optical axis direction to absorb the play.

FIG. 6 is a perspective view showing an assembled state of this play absorbing spring, and FIG. 7 is a sectional view taken along the line VII-VII of FIG. As shown in FIGS. 6 and 7, the first-second group fixed cylinder 413
Of the coil spring 44 to the extension cavity 447 of the straight advance key 430 of
6 is precharged and inserted, and a U-shaped plate (precharge member) 445 is pressed at one end, so a spring, 4
The addition of 46 will not increase the space.

The coil spring 446, when precharged, generates a force that causes bending and bending, but the cavity 447.
Since the thin plate 452 is surrounded on three sides by the thin plate 452 that is patched to the cavity 447, the remaining one is blocked, so that it does not bend. Further, since the first-second group cam ring 49 is provided, the thin plate 4
It doesn't bend without 52. Straight key 4
The position of the coil spring 446 is regulated by 30 except in the compression direction (optical axis direction).

The other end of the pre-charge member 445 comes into contact with the focus roller 411 when the focus roller 411 moves in the direction of the arrow to reach the end of the area A (from the retractable state to the image-capable state), and then to the area B of the focus roller 411. When moving, play is absorbed by the spring force. Since there are three focus rollers 411, the play absorbing spring mechanism is provided at three locations in the circumferential direction of the first-second lens group fixing cylinder 410.

With the above arrangement, since the spring force of the coil spring 446 does not work when the lens is extended from the retractable state to the image-capturing state, the extension load is extremely small and the image-capturing state is instantly achieved. Is performed. That is, the lens movable in the optical axis direction is configured to exert a biasing force in the optical axis direction when the amount of movement of the lens becomes equal to or larger than a desired amount.

The biasing force of the focus roller by the coil spring 446 also becomes the rotational force of the focus cam ring 415 via the focus cam 431. The rotational biasing force is also used for absorbing backlash between the teeth 445 of the focus cam ring 415 and the pinion 525.

As described above, the first group lens 61 and the second group lens 62 of the first lens barrel unit are fixed by elastic means (1-2).
The group fixed cylinder 410 or the second to which the 1-2 group fixed cylinder is fixed
The lens barrel unit) guarantees the optical accuracy.

Next, the strobe (flashing means) mounted on the zoom lens barrel will be described with reference to FIG. Auto Barrier Drive Unit The lens barrier of this zoom lens has a structure in which a flash unit having a xenon tube is incorporated and a strobe inner 83 is screwed to a strobe case 82.

The strobe case 82 is attached to the ears 81a and 81b of the auto barrier hinge 81, and the strobe shaft 84 is attached.
Is screwed into the arm portion 82a of the strobe case via the ear portion 81a. Further, the automatic barrier hinge receiver 85 is attached to the ear portion 81b.
It is screwed to the arm 82b to prevent it from coming off. Incidentally, the wiring of the flash unit passes through the inside of the arm portion 82b and comes out downward.

With this structure, the strobe case is about 18 around the auto barrier rotation axis 8 with respect to the auto barrier hinge 81.
It can be rotated 0 degrees. In the open state of the auto barrier shown in FIG. 8, the arms 82a and 82b of the strobe case 82 come into contact with the stopper 81c of the auto barrier hinge 81 and do not rotate further.

The arm 82a is provided with a transmission claw 82c,
In the automatic barrier large bevel gear 89, the receiving claw 89a provided on the automatic barrier large bevel gear 89 has the automatic barrier opening spring 8.
14 (both ends are fitted into holes (not shown) in the concave portion 82d of the arm portion 82a and holes (not shown) on the bottom surface of the auto-barrier large bevel gear 89, and are precharged in the direction of arrow 833). It is inserted into the recess 82d while being pressed against 82c. Therefore, the auto-barrier large bevel gear 89 can rotate in the arm 82a in the direction of the arrow 833 relative to the arm 82a against the spring force.
Since the transmission claw 82c and the receiving claw 89a are in contact with each other in the opposite direction, the relative rotation of each other is suppressed.

The automatic barrier small bevel gear 810 is coaxially fitted to the shaft portion 88a of the automatic barrier shaft 88 together with the automatic barrier transmission gear 811.
The transmission pawl 810a provided at 0 is the automatic barrier closing spring 8
The pre-clamping force of 15 (both ends are fitted into the hole 810b of the auto-barrier bevel tooth 810 and the hole 811b of the auto-barrier transmission gear 811 and pre-charged in the direction of the arrow 835) is received by the auto-barrier transmission gear 811. 81
It is pressed against 1a. Therefore, the auto-barrier bevel gear 810 is moved by the arrow 8 with respect to the auto-barrier transmission gear 811.
In the 34 direction, it is possible to rotate relative to the spring force,
In the opposite direction, the transmission claw 810a and the receiving claw 811a come into contact with each other, so that relative rotation between them is suppressed.

The auto-barrier large bevel gear 89 and the auto-barrier small bevel gear 810 mesh with each other by screwing the auto-barrier shaft 88 to the auto-barrier hinge 81, and the auto-barrier transmission gear 811 and the auto-barrier pinion gear 8 are engaged.
12 (which penetrates the auto barrier shaft) is also meshed. Further, the auto barrier disc gear 813 is press-fitted into the auto barrier pinion gear 812 by a D-cut pressure, and the auto barrier disc gear 813 meshes with the gear 445 of the focus cam ring 415.

The shaft portion 812a of the auto barrier pinion gear 812 is formed in the recess 414 of the auto barrier ring 414.
A, and the auto barrier ring receiver 87 is screwed to the auto barrier ring 414 to prevent it from coming off (the auto barrier ring 414 is assembled in the lens barrel, and the auto barrier hinge 81 is fixed to the first-second group). The shaft portion 812a of the auto-barrier pinion gear 812 is attached to the auto-barrier ring 414 when it is fitted to the outer diameter of the tip of the cylinder 413).

A focus output shaft 524, into which a focus pinion gear 525 is press-fitted, passes through the hole 414b of the auto barrier ring 414 (the focus output shaft 524 is supported by the rear portion 518 of the gear chassis and the auto barrier ring 414). Cage, focus pinion gear 525
Also meshes with the gear 445 of the focus cam ring 415.

FIG. 9 is a developed view of the focus cam ring 415. The focus cam 431 has the areas A and B as described above. In the area A from the retracted state to the standby state, the retracted state (focus cam 431 'focus When the focus cam ring 415 is rotated in the direction of arrow 836 by driving the focus pinion gear 525 from the roller 411 '), the auto barrier disc gear 8
The auto barrier pinion gear 812 is indicated by the arrow 8
It rotates in the 35 direction, and the automatic barrier transmission gear is indicated by the arrow 834.
And rotate in the opposite direction.

The receiving claw 8 of the automatic barrier transmission gear 811
11a rotates in a direction away from the transmission pawl 810a being pressed, but since the auto barrier closing spring 815 is precharged, the auto barrier small bevel gear 810 rotates in the same manner as the rotation of the auto barrier transmission gear 811. Therefore, the auto-barrier large bevel gear 89 rotates in the direction opposite to the arrow 833, and the receiving claw 89a pushes the transmission claw 82c to rotate the strobe case 82 in the direction of arrow 837.

Then, the strobe case 82 opens as the arrow 836 of the focus cam ring 415 rotates.
When the arms 82a and 82b are opened approximately 180 degrees, the rear surfaces of the arms 82a and 82b come into contact with the stopper 81c provided on the automatic barrier hinge 81 and the rotation thereof is restricted.

From the closing of the strobe case 82 to the rotation restriction, the gear ratios of the respective gears are set so that they are contained within the area A of the focus cam ring 415.

In the area B of the focus cam ring 415, even if the focus cam ring 415 rotates in the direction of the arrow 836, the rotation of the strobe case 82 is restricted by the stopper 81c, so that the automatic barrier bevel gear 810 rotates. However, the automatic barrier transmission gear 811 rotates relative to the automatic barrier small bevel gear 810 in the direction in which the receiving pawl 811a moves away from the transmission pawl 810a against the precharge force of the automatic barrier closing spring 815. Therefore, with respect to the rotation of the focus cam ring 415 in the area B in the direction of the arrow 836, there is only an operation for increasing the precharge amount of the auto barrier closing spring 815.

However, because of this precharging, the auto barrier disc gear 813 always urges the focus cam ring 415 to rotate in the direction opposite to the arrow 836, so that there is an inherent difference between the gears (focus drive transmission gear). Backlash is absorbed.

In an auto barrier of this type,
Since the barrier (strobe) is large, there is a possibility that the barrier may be accidentally closed by hand, or a closed barrier may be opened by hand.

When the barrier is closed by hand when the barrier is in the open state, the automatic barrier large bevel gear 89 similarly rotates in the direction of arrow 833 as the strobe case 82 closes. This is because the transmission claw 82c pushes the receiving claw 89a around. Therefore, the auto-barrier bevel gear 81
0 rotates in the direction of arrow 834.

However, since the transmission pawl 810a of the automatic barrier small bevel gear 810 moves away from the receiving pawl 811a, the automatic barrier small bevel gear 810 opposes the precharge force of the auto barrier closing spring 815. 811 absorbs the rotational displacement of the strobe case 82 in the direction opposite to the arrow 829 by rotating relative to 811 (the focus cam ring 415 does not rotate due to the holding force of the focus pinion gear 525, so the automatic barrier transmission gear 811). Will not be able to rotate).

When the barrier is opened by hand when the barrier is in the closed state, the transmission claw 82c causes the automatic barrier large bevel gear 8 to move.
Since it moves away from the receiving pawl 89a of No. 9 against the precharge force of the automatic barrier opening spring 814, the rotational displacement is similarly absorbed. Fresnel drive unit In FIG. 10, Fresnel 816 has Fresnel collar 817.
And attach Fresnel spring 822 to one end of Fresnel spring 822.
Insert into the groove of 16 and push in.

The arm 816c of the Fresnel plate 816 is inserted into the opening of the Fresnel hosi 819, the other end of the Fresnel spring 822 is inserted into a hole (not shown) of the Fresnel shaft 818, and the arrow 837 is inserted.
The Fresnel spring 822 is precharged by shaking in the direction and screwed to the Fresnel hosi 819.

With the above structure, the Fresnel plate 816 receives a rotational force in the direction of the arrow 837 with respect to the Fresnel hodge 819, but the projection 818a of the Fresnel shaft 818 and the step 816b of the Fresnel plate 816 come into contact with each other to regulate the position.

FIG. 11 is an exploded view of the Fresnel helicoid. The Fresnel helicoid (second driven member) 821 is provided with a cam contact surface 821a, and the Fresnel helicoid shaft 838 (first driven member) is a gear. 839 is fixed with a grub screw (for phase adjustment).

The Fresnel helicoid 821 is biased forward by the spring 840 on the Fresnel helicoid shaft 838. Groove 8 of Fresnel helicoid shaft 838
The screw 843 is inserted in the 38a, and the Fresnel helicoid 821 can move in the front-rear direction, but cannot rotate in the rotation direction relative to the Fresnel helicoid shaft 838.

The Fresnel cam 841 is attached to the focus cam ring 415, and when the focus cam ring 415 rotates (close to the focus side) in the focus area B, the Fresnel cam 841 pushes the cam contact surface 821a, so that the Fresnel helicoid 821 is pressed. Retreats.

Since the Fresnel hosi table 820 is mounted on the Fresnel helicoid 821, the Fresnel retracts as the focus moves closer to the near side, and the interval with the strobe case 82 is shortened.

The Fresnel helicoid 821 is passed through the Fresnel hodge table 820, and both ends are connected to the auto barrier hinges 81 and 3-4.
Both ends are supported by the flange portion of the group fixed cylinder 424 (FIG. 4).

The rotation of the third-fourth group cam ring 423 during zooming is transmitted from the gear 446 to the gear 821a of the Fresnel helicoid 821 via the ST gear parent 527 and the ST gear element 528 to drive the Fresnel helicoid.

The Fresnel hosi base 820 is mounted with the Fresnel helicoid 821 at the same time when the auto barrier drive unit is mounted on the first-second group fixed barrel 413, but the Fresnel hosi 819 is assembled from the entire surface of the lens barrel and screwed to the Fresnel hosi base 820.

This screwing is provided with play in the front-rear direction, and the screwing is performed while adjusting the distance between the strobe case 82 and the Fresnel plate 816.

The Fresnel plate 816 rotates in the direction opposite to the arrow 837 against the Fresnel spring 822 due to the closing operation of the strobe case 82 when the lens barrel is retracted, and at the time of standby, the Fresnel spring force is generated by the Fresnel spring force accompanying the opening operation of the strobe case 82.
Rotate in 37 directions.

As described above, Fresnel helicoid 821
Rotation of the third-fourth group cam ring 423 from the tooth 446 to S
It is transmitted via the T gear parent 527 and the ST gear child 528. Here, the transmission of the ST gear parent 527 from the tooth 446 is not deceleration but acceleration. This is because when the Fresnel helicoid 821 becomes heavy to some extent, the rotational load of the third-fourth group cam ring becomes excessive, and 3-
The gear 446 of the fourth group cam ring 423 is in a decelerated state, so that the Fresnel helicoid load increases and the rotation of the third to fourth group cam ring stops (the slip unit of the gear chassis unit 35 slips).

If this structure is not adopted (if the transmission from the tooth 446 to the Fresnel helicoid is not accelerated), the Fresnel helicoid 821 is further driven by zooming against the load of the Fresnel helicoid 821. This is because it will damage the helicoid mountain.

Further, since the driving force to the Fresnel helicoid 821 is transmitted from the zoom pinion 526 through the 3-4 group cam ring 423, even if the slip unit slips, for example, the 3-4 group cam ring 423 and The phase of the Fresnel helicoid 821 does not change.

Hereinafter, it will be described that the Fresnel helicoid has a structure in which the Fresnel helicoid is rotated by the zoom and moved forward and backward by the focus as shown in FIG. A Fresnel hosi mount 820 having a female helicoid is screwed into the Fresnel helicoid 821 of FIG. 11, and when the Fresnel helicoid 821 rotates, the Fresnel hosi mount 820 moves back and forth in the optical axis direction.

That is, the strobe case 8 including the xenon tube
On the other hand, the Fresnel plate 816 moves away when the zoom becomes tele.

The Fresnel helicoid is attached to the focus cam ring 415, and the Fresnel cam 841 moves back and forth in the optical axis direction at the time of focusing, and when the focus is close (the first lens group and the second lens group are extended), the Fresnel plate 816 strobes. It approaches the case 82. This is a varifocal type configuration in which the focal distance becomes shorter as the focus becomes closer, so the shooting angle of view changes when the focus is close and when the focus is infinite, and This is so that the strobe light can be effectively distributed even when there is a change.

[0121]

As described above, according to the present invention, the following effects can be obtained.

(1) Since the group zoom lens is divided into the first and second lens barrel units and combined with each other, the assembly is facilitated, and the optical adjustment and maintenance are facilitated.

(2) Since the second lens barrel unit having severe optical precision is directly attached to the camera body, the optical precision can be secured.

[0124]

[0125]

[0126]

[0127]

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of each state in which a zoom lens barrel of the present invention shifts from a collapsed state to a shooting state.

FIG. 2 is a development view of a focus cam.

FIG. 3 is an exploded perspective view showing the overall configuration of the zoom lens barrel of the present invention.

FIG. 4 is an exploded perspective view showing the configuration of the lens barrel unit shown in FIG.

5 is an exploded perspective view showing the configuration of the gear chassis unit shown in FIG.

FIG. 6 is a perspective view showing an assembled state of a play absorbing spring.

7 is a vertical cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is an exploded perspective view showing the configuration of the auto barrier unit.

FIG. 9 is an explanatory diagram for driving an automatic barrier.

FIG. 10 is an exploded perspective view showing a configuration of a Fresnel drive unit.

FIG. 11 is an exploded perspective view of a Fresnel helicoid.

FIG. 12 is a vertical sectional view of a conventional zoom lens barrel.

[Explanation of symbols]

43 1st group support frame 48 2nd group support frame 49 1-2 group cam ring 61 1st group lens 62 Second group lens 63 3rd group lens 64 4 group lens 410 1-2 group ring 413 1-2 group fixed cylinder 415 Focus cam ring 416 3rd group support frame 419 4th group support frame 423 3-4 group cam ring 424 3-4 group fixed cylinder 430 Straight key 446 Coil spring (elastic means) 816 Fresnel plate

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-287834 (JP, A) JP-A-57-116309 (JP, A) Actually open 62-146116 (JP, U) Actual-open Sho 62- 140510 (JP, U) Actual development Sho 56-7910 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 7/02 G02B 7/10

Claims (17)

(57) [Claims] 1. A first lens group, a second lens group,
In a zoom lens barrel having a third group lens and a fourth group lens in this order, a first fixed barrel for holding the first group lens and the second group lens and rotating with respect to the first fixed barrel A first cam barrel having a cam for moving the first group lens and the second group lens, and a second fixed barrel for holding the third group lens and the fourth group lens,
A second cam barrel that rotates with respect to the second fixed barrel and has a cam for moving the third group lens and the fourth group lens, and the first fixed barrel is the second fixed barrel; A zoom lens barrel characterized by being fixed to a fixed barrel of. 2. The zoom lens barrel according to claim 1, wherein the first fixed barrel is fixed to the second fixed barrel by screwing. 3. A first group lens, a second group lens from the subject side,
In a zoom lens barrel having a third group lens and a fourth group lens in this order, a fourth group support frame having a fourth group pin that supports the fourth group lens and extends in a radial direction, and an outer diameter of the fourth group support frame. And a third group support frame having a third group pin that supports the third group lens and extends in the radial direction, and the fourth group pin and the third group pin fitted to the outer diameter of the third group support frame. A 3-4 group fixed barrel having a straight-moving key for guiding only in the optical axis direction, and this 3-
The fourth group pin and the third group are moved in the optical axis direction by being fitted to the outer diameter of the fourth group fixed tube and being restricted in movement in the optical axis direction with the 3-4 group fixed tube to rotate around the optical axis. The 3-4 group cam ring having a cam surface, the 2 group supporting frame having the 2 group pins for supporting the 2 group lens and extending in the radial direction, and the 1 group fitted to the outer diameter of the 2 group supporting frame A first-group support frame having a first-group pin that supports a group lens and extends in the radial direction, and the second-group pin and the first group by fitting around the optical axis of the first-group support frame and rotating around the optical axis. It has a cam surface for moving the pin in the optical axis direction, and is key-connected to the key groove extending in the optical axis direction with the 3-4 group cam ring to rotate the 3-4 group cam ring around the optical axis. Is transmitted but the movement is not restricted in the optical axis direction with respect to the 3-4 group cam ring, and the 1-2 group cam ring is moved in the optical axis direction with respect to the 1-2 group cam ring. A first-second group ring that is regulated and has a focus pin that extends in the radial direction, and is fitted to the outer diameter of the first-second group cam ring so that the second-group pin, the first-group pin, and the focus pin are in the optical axis direction. A first-second group fixed barrel having a straight-moving key for guiding only, and a cam surface for fitting the outer diameter of the first-second group fixed barrel and moving the focus pin in the optical axis direction by rotating around the optical axis. And a focus cam ring having a zoom lens barrel. 4. The zoom lens barrel according to claim 3, wherein the 3-4 group fixed barrel and the 1-2 group fixed barrel each have a coupling surface and coupling means for coupling with each other. 5. The zoom lens barrel according to claim 3, wherein the third-fourth group fixed barrel has a coupling surface coupled to a camera body having a film aperture surface and a coupling means. 6. The zoom lens mirror according to claim 3, wherein the focus cam ring is sandwiched between the 3-4 group fixed barrel and the 1-2 group fixed barrel and is restricted in movement in the optical axis direction. Cylinder. 7. The focus cam ring is sandwiched between a second flange portion provided on the outer periphery of the third-fourth group fixed barrel and a first flange portion provided on the outer periphery of the first-second group fixed barrel, and is arranged in the optical axis direction. 4. The zoom lens barrel according to claim 3, wherein the movement of the zoom lens barrel is restricted. 8. The zoom lens barrel according to claim 3, wherein elastic force is applied between the fourth group support frame and the third group support frame in the optical axis direction. 9. The zoom lens barrel according to claim 3, wherein the first-second group ring is biased in the optical axis direction with respect to the first-second group fixed barrel by elastic means. 10. The zoom lens barrel according to claim 3, wherein the fourth group lens is supported by the fourth group support frame so as to be eccentrically adjustable. 11. The zoom lens barrel according to claim 3, wherein the second group lens is drivably supported on the second group support frame in a plane perpendicular to the optical axis. 12. The zoom lens barrel according to claim 3, wherein the first group lens is supported so as to be tiltable with respect to the first group support frame. 13. The zoom lens barrel according to claim 3, wherein the first group lens is detachably supported by the first group support frame. 14. The zoom lens barrel according to claim 3, wherein diaphragm means is coupled to the third group support frame on the object side of the third group lens. 15. The zoom lens barrel according to claim 3, wherein a lens shutter is coupled to the third group support frame on the subject side of the third group lens. 16. The zoom lens barrel according to claim 3, wherein the third-fourth group fixed barrel has a motor for driving the lens barrel and a drive transmission means mounting base plate including a drive transmission gear of the motor. 17. The third-fourth group cam ring has a portion internally contained in the first-second group cam ring, and the inner periphery portion of the outer circumference of the third-fourth group cam ring and the first-second group cam ring. The zoom lens barrel according to claim 3, wherein a desired gap is provided between the inner circumferences of the zoom lens barrel.