JP3288918B2 - 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 lens barrel having a function of supporting an impact from the front of the lens barrel.

[0002]

2. Description of the Related Art For example, in a zoom lens barrel, when an impact is applied to the lens barrel from the front with the lens barrel fitted with a helicoid fitted to the camera body side extended in the optical axis direction, a helicoid is formed. If the lead is small, the impact can be supported to some extent, but if the lead is large, the energy of the impact can be relatively easily converted into rotational motion. In a severe case, the mechanism may be damaged.

[0003]

SUMMARY OF THE INVENTION The present invention is based on the awareness of the above-mentioned problems in a zoom lens barrel, and reliably supports the impact applied to the lens barrel from the front even if the lead of a helicoid or the like in the mechanism for moving the lens barrel is large. It is another object of the present invention to provide a lens barrel having a function of protecting each part from damage.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cam cylinder having a cam groove penetrating a peripheral surface thereof and driven straight in the optical axis direction; an optical axis fitted on the outer periphery of the cam cylinder; And a follower tube having a cam groove and a follower that fits continuously into the linear guide groove, and a follower tube that fits on the inner periphery of the cam tube. The cam groove has a wide trapezoidal cross section on the optical axis center side and has a circumferential groove at a rear end thereof, and the cam cylinder extends along a surface of the cam groove on the rear side in the optical axis direction with respect to the circumferential groove. It has an impact receiving surface consisting of a flange surface orthogonal to the optical axis, and the follower of the follower cylinder is
A frustum-shaped conical follower that is integrally molded with the follower cylinder and that engages with the trapezoidal cross-section cam groove, and a roller follower that is screwed to the apex of the frustum-shaped conical follower and fits into the rectilinear guide groove of the rectilinear guide cylinder When a rearward force is applied to the cam cylinder in a state where the follower of the follower cylinder is engaged with the circumferential groove of the cam groove of the cam cylinder, the roller follower and the impact receiving surface come into contact with each other, It is characterized in that a relative movement between the cam cylinder and the follower cylinder in the optical axis direction is prevented.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. In this embodiment, the present invention is applied to the lens shutter type zoom lens camera shown in FIG. 17, and the concept of the zoom lens camera will be described first with reference to FIG. The lens configuration is the front group lens L
1 and a rear lens unit L2.

[0006] The camera body includes an overall movement motor control means 60, a rear group movement motor control means 61, and a zoom operation means 6.
2, shutter release means 63, distance measuring device 64, photometric device 65, and AE motor control means 66 are provided.

When the zoom operation means 62 such as a zoom lever provided on the camera body is operated, the whole moving motor control means 60 controls the whole moving motor 25 by a zoom lens comprising a front lens group L1 and a rear lens group L2. A command for moving the camera from the wide side to the tele side, or a command for moving the camera from the tele side to the wide side. The focal length is changed by the operation of the zoom operation unit 62 by the photographer, and is set to an arbitrary focal length. The image magnification of the finder field is changed in conjunction with the focal length change by the zoom operation means 62. Therefore, the photographer can know the change in the focal length due to the operation of the zoom operation unit 62 by observing the change in the image magnification of the finder field. The focal length set by the operation of the zoom operation unit 62 can be recognized by, for example, a numerical value displayed on an LCD display panel (not shown).

When the shutter release means 63 is operated, the whole-group moving motor control means 60 is driven by the rear-group moving motor control means 61.
At the same time, the overall movement motor 25 is driven to focus the zoom lens on the subject. The shutter release means 63
The shutter button is constituted by a release button. When the shutter button is depressed one step, a distance measurement command to the distance measurement device 64 and a photometry command to the photometry device 65 are given. Then, the shutter 27 of the AF / AE shutter unit 21 is operated. The shutter 27 receives the photometric output from the photometric device 65 and opens its shutter blade 27a for a predetermined time.

When operated, the zoom operation means 62 drives the whole movement motor 25 to move the front lens group L1 and the rear lens group L2 integrally. At the same time as this movement, the rear group moving motor 30 may be operated via the rear group moving motor control means 61. However, the important point of this zoom lens camera is that the front group lens L1 and the rear group lens The movement of L2 is not performed by the conventional zooming concept of continuously changing the focal length without moving the focal point position. That is, when the zoom operation means 62 is operated, only the whole movement motor 25 is operated, and the front group lens L
1 and the rear group lens L2 are moved back and forth without changing the air gap between them, and the front group lens L1 and the rear group lens L2 are operated by operating both the overall movement motor 25 and the rear group movement motor 30. Is moved while changing the air gap between the two.

In the embodiment of the present invention, it is impossible that a subject at a specific distance is always in focus. However, in a lens shutter type camera such as this camera which does not observe an image obtained by a photographing optical system, focus is obtained at the time of shutter release. There is no problem at all if it fits. In the aspect, the front lens group L1 and the rear lens group L2 are moved while allowing the focal position to move, and both the entire moving motor 25 and the rear group moving motor 30 are operated during the shutter release to focus. .

After executing any one of the above-described control modes in response to the operation of the zoom operating means 62, the shutter release means 63 is operated in at least a part of the focal length range of the focal length set by the zoom operating means 62. When this is done, the whole moving motor 25 and the rear group moving motor 30
Are operated to focus on the subject. The amount of movement of the front group lens L1 and the rear group lens L2 by the entire movement motor 25 and the rear group movement motor 30 at this time is not limited to the amount of movement obtained by subject distance information by the distance measuring device 64,
It is determined in consideration of the amount of movement obtained by the focal length information set by the zoom operation means 62. As described above, when the shutter release means 63 is operated and both the overall movement motor 25 and the rear group movement motor 30 are operated to perform the focusing operation, the degree of freedom in controlling the lens position is increased, and the control thereof is performed. Becomes easier.

It should be noted that, theoretically, when the zoom operating means 62 is operated, the whole moving motor 25 and the rear group moving motor 30 are moved.
Without operating any of them, only the view magnification of the finder and the focal length information are changed, and the shutter release means 63
Is operated, the focal length information and the distance measuring device 64
, The front and rear group lenses L1 and L2 are moved to the positions uniquely determined by the focal length information and the subject distance information. It can also be done.

Next, an embodiment in which the zoom lens barrel having the above concept is concretely described mainly with reference to FIGS. First, the schematic configuration and operation of the zoom lens barrel 10 will be described.
A movable lens barrel 19, a third movable lens barrel 16, and a fixed lens barrel block 12 are provided. The third movable lens barrel 16 is screwed to the cylindrical portion of the fixed lens barrel block 12, and moves forward and backward in the optical axis direction with rotation. The third movable lens barrel 16 has a rectilinear guide cylinder 17 whose rotation is regulated and moves inward in the optical axis direction, and the second movable lens barrel 19 rotates relative to the rectilinear guide cylinder 17. While moving back and forth in the optical axis direction. First movable lens barrel 2
In the case of 0, the rotation is restricted, and moves in the optical axis direction by the relative rotation with respect to the second movable lens barrel 19. The entire moving motor 25 is fixed to the fixed lens barrel block 12 and has an AE motor 29 and a rear group moving motor 30 mounted thereon.
0 is fixed to the first movable lens barrel 20. The front group lens L1 is a lens having a positive power supported by the lens support cylinder 34, and the rear group lens L2 is a lens support cylinder 5
This is a lens having negative power supported by zero.

The fixed lens barrel block 12 fixed in front of the aperture plate 14 of the camera body has a female helicoid 12a, a plurality of rectilinear guide grooves 12b parallel to the optical axis O, on the inner peripheral surface of the cylindrical portion. have. A code plate 13a having a predetermined pattern is fixed to the bottom of one of the plurality of straight guide grooves 12b. This code plate 13
a is configured as a part of the flexible printed circuit board 13 located outside the fixed lens barrel block 12. The aperture plate 14 has an aperture 14a for determining an exposure area on the film.

The cylindrical portion of the fixed lens barrel block 12 has a gear housing portion 12c bulging radially outward and extending in the optical axis direction.
Are formed (see FIG. 13). This gear housing 12
A drive pinion 15 long in the optical axis direction is rotatably housed in c. The drive pinion 15 has both ends of the shaft 7 rotatably supported by a support hole 4 provided in the fixed lens barrel block 12 and a support hole 31 a provided in the gear support plate 31. The tooth surface of the drive pinion 15 projects from the inner peripheral surface of the fixed lens barrel block 12.

A third movable barrel 16 is screwed into the inner periphery of the fixed barrel block 12. This third movable lens barrel 16
Has a plurality of linear guide grooves 16 extending in the optical axis direction on the inner peripheral surface.
a male helicoid 16a meshing with the female helicoid 12a of the fixed lens barrel block 12 and an outer peripheral gear 16b meshing with the drive pinion 15 at the rear end outer circumference (see FIG. 12).
And The drive pinion 15 is connected to the third movable lens barrel 1.
6 in the entire moving range in the optical axis direction.
And has an axial length that meshes with it.

A linear guide tube 17 is supported on the inner periphery of the third movable lens barrel 16 so as to be integrally movable with the third movable lens barrel 16 in the optical axis direction and relatively rotatable about the optical axis. . The rectilinear guide cylinder 17 includes a rear end flange portion 17d having a plurality of engagement protrusions 17c protruding radially outward on the rear outer periphery,
A retaining flange 1 having a smaller diameter than the flange 17d, which is provided with a slight gap in front of the rear end flange 17d.
7e. A plurality of notches 17f are formed in the circumferential direction of the retaining flange 17e. The third movable lens barrel 16 has a plurality of engaging projections 16d (FIG. 15) protruding radially inward on the inner periphery of the rear end portion.
d is inserted through the notch 17f so that both flanges 17
It is located in the gap between d and 17e, and is connected to the rectilinear guide tube 17 by rotating relative to the rectilinear guide tube 17. An aperture plate 23 having an opening 23a having substantially the same shape as the aperture 14a is fixed to a rear end surface of the straight guide cylinder 17. The engagement protrusion 17c is slidably engaged with a straight guide groove 12b parallel to the optical axis O of the fixed lens barrel block 12, and its rotation is restricted. The contact terminal 9 for slidingly contacting the code plate 13a and generating a signal corresponding to the focal length during zooming is fixed to the engagement protrusion 17c ', which is one of the engagement protrusions 17c.

The straight guide cylinder 17 also has an inner peripheral surface
A plurality of linear guide grooves 17a parallel to the optical axis O and a plurality of lead grooves 17b penetrating the peripheral wall of the guide cylinder 17 are formed.

A second movable lens barrel 19 is fitted on the inner periphery of the straight guide cylinder 17. The second movable lens barrel 19 has a plurality of lead grooves 19 that are inclined on the inner peripheral surface in a direction opposite to the lead grooves 17b.
and a plurality of follower projections 19a protruding radially outward on the outer periphery of the rear end, and a follower pin 18 located on the follower projection 19a. The lead groove 19c
Are inclined at a constant angle with respect to the circumferential direction and the optical axis (direction).

A first movable lens barrel 20 is fitted on the inner periphery of the second movable lens barrel 19. The first movable lens barrel 20 engages a plurality of follower pins 24 provided on the outer periphery of a rear end portion with a corresponding inner peripheral lead groove 19c, and a linear guide member 22.
Is guided straight ahead. This straight guide member 22 is
As shown in FIGS. 7 and 8, an annular portion 22a, a pair of guide legs 22b extending from the annular portion 22a in the optical axis direction,
The linear guide groove 1 protrudes radially outward of the annular portion 22a.
A guide leg portion 22b is inserted between the inner peripheral surface of the first movable lens barrel 20 and the AF / AE shutter unit 21 so as to be capable of linearly guiding. are doing.

The annular portion 22a of the linear guide member 22
The second movable lens barrel 19 is coupled to the rear end portion so as to be integrally movable in the optical axis direction and relatively rotatable around the optical axis. The rectilinear guide member 22 has a rear end flange portion 22d having a plurality of engagement protrusions 28 protruding radially outward on a rear outer periphery.
And a retaining flange portion 22c smaller in diameter than the flange portion 22d, provided with a slight gap in front of the rear end flange portion 22d, and a plurality of notches 22e in the circumferential direction of the retaining flange portion 22c. (See FIG. 7). The second movable lens barrel 19 has a plurality of engaging projections 19b (FIG. 15) protruding radially inward on the inner periphery of the rear end. The linear guide member 22 is positioned in the gap between the flange portions 22c and 22d.
Relative to the straight guide member 22. With the above configuration, when the second movable barrel 19 rotates in the forward and reverse directions, the first movable barrel 20 moves straight forward and backward with respect to the second movable barrel 19 in the optical axis direction while the rotation is restricted. I do.

At the front end of the first movable lens barrel 20, a barrier device 35 having barriers 48a and 48b is mounted.
An AF / AE shutter unit 21 having a shutter 27 including three shutter blades 27a (FIG. 11) is fitted and fixed to the inner peripheral surface. The AF / AE shutter unit 21 has a plurality of fixing holes 40a (FIG. 9) formed at equal angular intervals on the outer periphery of the shutter mount 40. The plurality of follower pins 24 also serve as fixing means for the AF / AE shutter unit 21, and include a pin hole 20 a formed in the first movable lens barrel 20 and a fixing hole 40 a
Further, the follower pin 24 is fitted and fixed, and the shutter unit 21 is fixed to the first movable lens barrel 20 (see FIG. 10). The follower pin 24 can be fixed by, for example, bonding, screwing, or the like. Reference numeral 41 denotes a decorative plate fixed to the front end of the first movable lens barrel 20.

The AF / AE shutter unit 21 corresponds to FIG.
As shown in FIG. 1 and FIG. 16, a shutter mounting base 40,
A shutter blade support ring 46 fixed to a rear portion of the shutter mount 40, and a lens support tube 50 (rear group lens L) supported to be relatively movable with respect to the shutter mount 40.
2). The front lens L1, the AE motor 29, and the rear group moving motor 30 are supported by the shutter mount 40. The shutter mount 40 has an annular portion having a shooting opening 40d through which the lens support tube 34 is inserted, and three legs 40b extending rearward from the annular portion. Two of the gaps between the three legs 40b are a pair of guide legs 2 of the straight guide member 22.
2b is configured as a rectilinear guide portion 40c which slidably engages and guides the movement.

The shutter mount 40 further includes an AE gear train 45 for transmitting the rotation of the AE motor 29 to the shutter 27.
And the rotation of the rear group moving motor 30 with the screw shaft 4
3 and the photo interrupters 56 and 57 connected to the flexible printed circuit board 6.
Rotating plates 58, 5 having a number of circumferential slits
9 are supported. The photointerrupter 57 and the rotating plate 59 constitute a rear group moving motor encoder for detecting the rotation of the rear group moving motor 30, and the AE motor 29 is formed by the photointerrupter 56 and the rotating plate 58.
An AE motor encoder that detects the rotation of the motor is configured.

Between the shutter mount 40 and the shutter blade support ring 46 fixed to the mount 40, the shutter 2
7, a support member 47 for pivotally supporting the three shutter blades 27a of the shutter 27, and an annular driving member 49 for applying a rotational power to the shutter blades 27a. The annular driving member 49 includes three operation protrusions 49a respectively engaging with the three shutter blades 27a at equal angular intervals. The shutter blade support ring 46 is provided at the front wall with the photographing opening 4.
6a and three support holes 46b provided at equal angular intervals around the photographing opening 46a.
A flexure restricting surface 46c exposed from Oc and slidably supports the inner peripheral surfaces of the pair of guide legs 22b.

A support member 47 located in front of the shutter blade support ring 46 includes a photographing opening 47a facing the photographing opening 46a, and three shaft portions 47b (see FIG. 11) facing the three support holes 46b, respectively. (Only parts are shown). Each of the three shutter blades 27a has, at one end, a shaft hole 27b through which the shaft 47b is inserted, and at the other end, a shielding portion that shields the imaging openings 46a, 47a.
An elongated hole 27c is provided between the one end and the other end to allow the operation projection 49a to pass therethrough. The support member 47 includes a shaft portion 47b supporting the shutter blade 27a.
The shutter blade support ring 46 is fixed to the shutter blade support ring 46 in a state of being fitted into the corresponding support hole 46b.

The annular driving member 49 has a gear train 4
5 has a gear portion 49b for receiving rotation from. The support member 47 has three arc grooves 47c in the circumferential direction at positions close to the three shaft portions 47b. The three operation projections 49a of the annular driving member 49 penetrate through the three arc grooves 47c, and the long holes 27 of the respective shutter blades 27a.
c. The shutter blade support ring 46 is inserted from the rear side of the shutter mount 40 while supporting the annular driving member 49, the support member 47, and the shutter 27, and is screwed to the shutter mount 40.

Behind the shutter blade support ring 46, there is disposed a lens support cylinder 50 supported on the shutter mount 40 via slide shafts 51 and 52 so as to be relatively movable. The shutter mount 40 and the lens support cylinder 50 are urged to move in the direction away from each other by the coil spring 3 fitted to the slide shaft 51, thereby eliminating play between them. The drive gear 42a provided in the gear train 42 is restricted from moving in the axial direction, and a female screw is formed on the inner periphery thereof. A screw shaft 43 having one end fixed to the lens support cylinder 50 is screwed to the female screw.
And the screw shaft 43 constitute a feed screw mechanism. Therefore, when the rear group moving motor 30 is driven to rotate and the drive gear 42a rotates forward or backward, the screw shaft 43 advances and retreats with respect to the drive gear 42a, and is supported by the lens support tube 50, that is, the support tube 50. The rear lens group L2 moves relative to the front lens group L1.

At the front of the shutter mount 40, holding members 53, 55 for holding the motors 29, 30 and the like supported by the shutter mount 40 are screwed. The motors 29 and 30 and the photo interrupters 56 and 57 are connected to the flexible printed circuit board 6 having one end fixed to the shutter mount 40. In a state where the first to third movable lens barrels 20, 19, 16 and the AF / AE shutter unit 21 and the like are assembled, an aperture plate 23 is fixed to the rear end face of the straight guide cylinder 17, and the front end of the fixed lens barrel block 12. An annular retaining member 33 is fitted to the portion.

Here, a structure provided in the zoom lens barrel 10 for supporting an impact applied to the barrel from the front will be described with reference to FIGS.

That is, the impact support structure has a lead groove (cam groove) 17b penetrating the peripheral surface thereof, and the linear guide cylinder (cam cylinder) 17 driven linearly in the optical axis direction. A third movable lens barrel (straight guide cylinder) 16 having a straight guide groove 12c parallel to the optical axis O and fitted on the outer periphery of the lens;
A follower pin 18 and a follower projection 19 which form a follower and are fitted in the lead groove 17b and the linear guide groove 12c continuously.
and a second movable lens barrel (follower cylinder) 19 having an a. Follower protrusion 1
9a is formed at the rear end of the second movable barrel 19, so that the impact of the rear end of the straight guide tube 17 at the wide end position of the zoom lens barrel 10 and the lens storage position (see FIG. 15). Approaches the receiving surface 17m.

The ring member 18a of the follower pin 18
As shown in FIG. 3, at the center thereof, there is provided a shaft hole 81a for inserting the screw portion 80b of the center fixing screw 18b, and a receiving portion 81b for accommodating the head portion 80a of the center fixing screw 18b. On the lower outer peripheral edge of the ring member 18a,
An inclined surface 81c whose diameter gradually decreases downward is formed. The lead groove 17b of the rectilinear guide cylinder 17 has a trapezoidal cross section with a large width on the center side (inner diameter side). The lead groove 17b has an inclined guide surface formed at substantially the same angle as the inclined guide surface 81c, in which the inclined surface 81c provided on the ring member 18a is brought into sliding contact with the outer peripheral end surface of the narrow portion on the outer diameter side. 17n are provided.

The rectilinear guide cylinder 17 has a solid impact receiving surface 17m at the rear end (on the rear side of the optical axis) of the lead groove 17b for engaging with a follower. This follower is formed of resin integrally with the second movable lens barrel 19 and has a frustum-shaped (frustum-shaped follower) 19a that engages with the trapezoidal cam groove. The ring member (roller follower) 18a fixed to the apex with a center fixing screw 18b and fitted in the straight guide groove 16c of the third movable lens barrel 16, the ring member 18a
Engages with the impact receiving surface 17m. Follower projection 19a
Is formed with a screw hole 19d penetrating from the top to the inner diameter side. At the rear end of the lead groove 17b, the lead groove 1 is provided.
A circumferential groove 17b 'connected to 7b is provided. The impact receiving surface 17m is a flange surface along the circumferential groove 17b 'in the retaining flange portion 17e.

On the inner peripheral side of the retaining flange portion 17e and the rear end flange portion 17d which are the rear end surfaces of the straight guide cylinder 17,
An inlet groove 17p is formed to guide the frustoconical follower projection 19a to the lead groove 17b having a trapezoidal cross section. The impact receiving surface 17m provided on the retaining flange portion 17e of the rectilinear guide cylinder 17 guides the follower projection 19a to the trapezoidal cross-sectional lead groove 17 and then screws the apex of the follower projection 19a to the top of the follower projection 19a. A ring member 18a protruding from the groove 17b to the outside of the rectilinear guide tube 17 is engaged to constitute a retaining wall for restricting the second movable lens barrel 19 from coming off from the rectilinear guide tube 17. Ring member 1 which is a roller follower screwed to the vertex of a frustum-shaped follower protrusion 19a
8a is slidably fitted in the rectilinear guide groove 16c of the third movable lens barrel 16 on the outer peripheral side of the rectilinear guide cylinder 17. As described above, since the follower projection 19a is slidably fitted in the lead groove 17b of the rectilinear guide cylinder 17, the second movable barrel 1
9 moves straight while rotating in the optical axis direction when the third movable lens barrel 16 rotates.

The lead groove 17b is formed in a linear shape inclined at a constant angle with respect to the circumferential direction and the optical axis (direction). When the third movable lens barrel 16 rotates at a constant speed, the follower groove 17b moves. It is moved at a constant speed in the direction of the optical axis. In other words, the lead groove 17b is a form in which the second moving barrel 19 is moved at a constant speed in the optical axis direction via the follower when the movement speed change in the cam groove is O, and is naturally included in the cam groove. It is.

In general, in a zoom lens barrel, when an impact is applied from the front to the lens barrel in a state where the lens barrel fitted with a helicoid on the camera body is extended in the optical axis direction, the lead of the helicoid is small. The impact can be supported to some extent. However, when the lead of the helicoid becomes large, the energy of the impact from the front of the lens barrel is relatively easily converted into rotational motion, and the forward / backward drive mechanism of the lens barrel is forcibly rotated in the reverse direction. There is a fear that the mechanism may be damaged.

When such a phenomenon occurs with the lens barrel extended to a certain extent, the energy of the impact (see arrow A in FIG. 6) is converted into a rotational motion, and a clutch is interposed in the advance / retreat drive mechanism. If it is, damage can be avoided by the function of the clutch. However, when the lens barrel is retracted toward the wide end and is at the position of the lead 0 (for example, as shown in FIG.
b '), the impact from the front acts directly on the circumferential groove 17b' without being converted into a rotational movement (see arrow B in FIG. 6).

When the zoom lens barrel 10 is in the lead 0 position where the clutch cannot function, the lead groove 17
Since the ring member 18a protruding outward from the b is configured to approach the impact receiving surface 17m of the linear guide tube 17, even if an impact is received in this state, the ring member 1a
8a comes into contact with the solid impact receiving surface 17m.
Since m reliably supports the impact in the direction of arrow B in FIG. 6, no damage occurs to each part.

In the present embodiment, the front lens group L1 and the rear lens group L2 are respectively connected to the AF / AE shutter unit 21.
The AE motor 29 and the rear group moving motor 30 are mounted on the unit 21. According to this configuration, there is an advantage that the supporting structure and the driving structure of the front lens unit L1 and the rear lens unit L2 can be simplified, but at least one of the front lens unit L1 and the rear lens unit L2 is
Shutter mount 40, annular drive member 49, support member 4
7, the zoom lens is realized even if the AF / AE shutter unit 21 including the shutter 27 and the shutter blade holding ring 46 is provided as a separate member and is supported by a support member different from the unit.

The present zoom lens camera operates as follows. FIG. 15 in which the zoom lens barrel 10 is most retracted
When the power switch (not shown) is turned on in the lens retracted state, the overall movement motor 25 is driven to rotate slightly in the forward direction. Then, this rotation is transmitted to the drive pinion 15 via the gear train 26 supported by the support portion 32, and the third movable barrel 16 is rotated in the extending direction.
The movable barrel 19 and the first movable barrel 20 are connected to the third movable barrel 16.
The camera is slightly extended in the optical axis direction, and the camera is in a photographable state in which the zoom lens is positioned at the wide end.

In this photographing enabled state, when the zoom operation means 62 is operated to the telephoto side, the whole movement motor 25 is driven to rotate in the forward direction via the whole movement motor control means 60, and is driven via the drive pinion 15 and the outer peripheral gear 16b. To rotate the third movable barrel 16 in the extending direction. Therefore,
The third movable lens barrel 16 is extended from the fixed lens barrel block 12 due to the relationship between the female helicoid 12a and the male helicoid 16a, and at the same time, the straight guide tube 17 is fixed by the relationship between the engagement projection 17c and the straight guide groove 12b. Block 12
With the third movable lens barrel 16 in a state of not rotating relative to the optical axis, it advances forward of the optical axis. At this time, the second movable lens barrel 19
The follower pin 18 is connected to the lead groove 17b and the linear guide groove 1
By simultaneously engaging with the third movable lens barrel 6c, the second movable lens barrel 6 relatively moves in the same direction as the third movable lens barrel 16 and moves forward in the optical axis with respect to the third movable lens barrel 16. The first movable lens barrel 20 is
Since the linear movement guide member 22 guides the linear movement and the follower pin 24 is moved and guided by the lead groove 19 c, the second movable lens barrel 19 and the AF / AE shutter unit 21 are not rotated relative to the fixed lens barrel block 12. Advances ahead of the optical axis.

While the zoom lens barrel 10 is driven in this manner, the rear group moving motor 30 is not driven, so that the front group lens L1 and the rear group lens L2 are integrated with the optical axis while maintaining a constant distance from each other. (See FIG. 14). The focal length set by the zoom operation unit 62 is displayed by a display unit (not shown).

When the release button is depressed one step at an arbitrary focal length set by the zoom operating means 62, a distance measuring command is given to the distance measuring device 64 and a light measuring command is given to the light measuring device 65, so that the distance measuring and measuring operations are performed. Photometry is started. Thereafter, when the release button is depressed two steps, both the whole moving motor 25 and the rear group moving motor 30 move the moving amount obtained from the subject distance information by the distance measuring device 64 and the focus set by the zoom operating means 62. The AE motor control means 6 moves the front lens group L1 and the rear lens group L2 by a movement amount determined in consideration of the movement amount obtained from the distance information to set the focal length and focus on the subject.
The AE motor 29 rotationally drives the annular driving member 49 in accordance with the subject luminance information from the photometric device 65 via 6 to drive the shutter 27 so as to satisfy a predetermined exposure. After the end of the shutter release, both the overall movement motor 25 and the rear group movement motor 30 are immediately driven, and the front lens group L1 and the rear lens group L2 are returned to the state before the shutter release.

When the zoom operation means 62 is operated to the wide side, the whole moving motor 25 is driven to rotate in the reverse direction, and
The movable lens barrel 16 is rotated in the retracting direction, and is retracted into the fixed lens barrel block 12 together with the rectilinear guide cylinder 17. At the same time, the second movable lens barrel 19 is retracted into the movable lens barrel 16 while rotating in the same direction as the third movable lens barrel 16, and
The movable lens barrel 20 is moved by A with respect to the rotating second movable lens barrel 19.
It is moved together with the F / AE shutter unit 21.
Also during this retraction drive, the rear group moving motor 30 is not driven, as in the above-described retraction drive. When the power switch is turned off after the zoom lens moves to the wide end position, the zoom lens barrel 10 is moved into the lens storage position shown in FIG.

[0045]

As described above, according to the present invention, even when a lead such as a helicoid in the lens barrel advancing / retracting mechanism is large, the shock applied to the lens barrel from the front can be reliably supported.
A lens barrel having a function of protecting each part from damage can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of a zoom lens barrel according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a straight guide tube of the zoom lens barrel alone;

FIG. 3 is a side sectional view for explaining an impact support structure of the zoom lens barrel.

FIG. 4 is a side sectional view for explaining an impact support structure of the zoom lens barrel.

FIG. 5 is an exploded view of a rectilinear guide tube for explaining an impact support structure of the zoom lens barrel.

FIG. 6 is an enlarged view of a part of FIG. 5 for explaining an impact support structure of the zoom lens barrel.

FIG. 7 is a perspective view showing a main part of a linear guide mechanism of the zoom lens barrel.

FIG. 8 is a perspective view showing a state different from FIG. 7 of a main part of the straight traveling guide mechanism.

FIG. 9 is an exploded perspective view showing a main part of the zoom lens barrel.

FIG. 10 is a perspective view showing a state in which an AF / AE shutter unit of the zoom lens barrel is assembled to a first movable barrel.

FIG. 11 is an exploded perspective view showing main members of an AF / AE shutter unit of the zoom lens barrel.

FIG. 12 is a perspective external view showing a third movable lens barrel of the zoom lens barrel.

FIG. 13 is a front view showing a fixed lens barrel block of the zoom lens barrel.

FIG. 14 is an upper half sectional view showing a maximum extended state of the zoom lens barrel.

FIG. 15 is an upper half sectional view showing a main part of the zoom lens barrel in a lens housed state.

FIG. 16 is an exploded perspective view showing the entire zoom lens barrel.

FIG. 17 is a block diagram showing a control system for controlling the operation of the zoom lens barrel.

[Explanation of symbols]

 Reference Signs List 10 zoom lens barrel 12b straight guide groove 16 third movable barrel (straight guide tube) 16c straight guide groove 17 straight guide tube (cam barrel) 17b lead groove (cam groove) 17b 'circumferential groove 17d rear end flange portion 17e Retaining flange part 17m Impact receiving surface 17p Inlet groove 18 Follower pin 18a Ring member (roller follower) 18b Center fixing screw 19 Second movable lens barrel (follower cylinder) 19a Follower projection (frustum of conical follower) O Optical axis

Continuation of front page (56) References JP-A-1-306808 (JP, A) JP-A-2-201308 (JP, A) JP-A-54-118240 (JP, A) JP-A-9-230193 (JP, A) JP-A-7-43584 (JP, A) JP-A-4-37915 (JP, U) JP-A-62-141114 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) G02B 7/02-7/105

Claims (1)

(57) [Claims] 1. A cam barrel having a cam groove penetrating in a peripheral surface thereof and driven in a straight line in the optical axis direction; and a rectilinear guide cylinder fitted in an outer periphery of the cam cylinder and having a straight guide groove parallel to the optical axis. And a follower tube having a follower fitted continuously to the cam groove and the straight guide groove, and a follower tube fitted to the inner periphery of the cam tube. It has a wide trapezoidal cross section and has a circumferential groove at its rear end, and the cam cylinder extends from a flange surface orthogonal to the optical axis along a surface behind the circumferential groove of the cam groove in the optical axis direction. The follower of the follower cylinder is formed by resin-integral molding of the follower cylinder, and the truncated conical follower engaging with the trapezoidal section cam groove is screwed to the apex of the truncated conical follower. ,
A roller follower that fits into the rectilinear guide groove of the rectilinear guide cylinder, and a rearward force is applied to the cam cylinder in a state where the follower of the follower cylinder is engaged with the circumferential groove of the cam groove of the cam cylinder. At this time, the roller follower and the impact receiving surface come into contact with each other to prevent relative movement of the cam barrel and the follower barrel in the optical axis direction.