JP3569497B2 - Lens barrel - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a lens barrel.
[0002]
[Prior art and its problems]
As an example of the lens barrel, a cam ring that is driven to rotate and is moved in the optical axis direction, and a lens frame ring that is located outside the cam ring and forms the outer peripheral surface of the zoom lens barrel, is provided. In some cases, a follower pin provided on a lens frame ring is engaged with a cam groove to rotate the cam ring, thereby moving the lens frame ring together with the cam ring in the optical axis direction.
[0003]
However, since the lens frame ring is a member forming the outer peripheral surface of the lens barrel, an external force may be directly applied to the lens frame ring. In this case, the external force is transmitted to the cam ring through the follower pin, and the cam ring is deformed. The follower pin may come off or the cam ring may be damaged. Therefore, in order to increase the strength of the cam ring, it is conceivable to increase the thickness of the cam ring or to form the cam ring with a material having high rigidity. However, in the former case, the size and weight are increased, and in the latter case, the material is increased. There was a problem that cost and processing cost were required.
[0004]
[Object of the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrel in which even if an external force is applied to a lens frame ring forming an outer peripheral surface of the lens barrel, the external force does not cause deformation or the like of the cam ring.
[0005]
Summary of the Invention
The lens barrel of the present invention is a cam ring supported so as to move in the optical axis direction as it is rotated; a movement supported on the inner peripheral side of the cam ring so as to restrict rotation and allow linear movement in the optical axis direction. A lens group frame; a lens group cam groove formed on the inner peripheral surface of the cam ring; and a follower pin provided on the movable lens group frame that fits into the lens group cam groove. A lens group cam mechanism for moving the movable lens group frame in the optical axis direction; a lens frame ring supported on the outer peripheral side of the cam ring so as to restrict rotation and to be able to move linearly in the optical axis direction; A lens frame ring cam groove formed on the outer peripheral surface; and a follower pin provided on the lens frame ring to be fitted in the lens frame ring cam groove. The rotation of the cam ring causes the lens frame ring to move in the optical axis direction. A lens frame cam mechanism and a lens frame ring. The cam groove has substantially the same shape with different positions in the optical axis direction in a region where the movable lens group frame advances and retreats in the optical axis direction, and the follower pin of the movable lens group frame and the follower pin of the lens frame ring are: It is characterized by being located on substantially the same axis in a direction parallel to the optical axis.
[0006]
Further, there is provided a spring means for moving and biasing the movable lens group frame and the lens frame ring in a direction approaching or separating from each other in the optical axis direction.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
[Overall description of zoom lens barrel]
The illustrated embodiment is an embodiment in which the present invention is applied to a zoom lens barrel for a digital still camera. As is clear from FIGS. 5 to 7, the lens system of the present embodiment is a three-unit type having a first lens unit L1, a second lens unit L2, and a third lens unit L3 in order from the object side. The first lens unit L1 and the second lens unit L2 move on the optical axis while changing the air gap, so that zooming is performed, and focusing is performed by the third lens unit L3.
[0008]
In the present zoom lens barrel, elements fixed to the camera body (members that do not move linearly or rotate in the optical axis direction) are a housing 11, a shaft retainer 12, and a fixed ring 13 shown in FIGS. The housing 11 and the fixed ring 13 are formed with a fixed flange 13a (the fixed flange of the housing 11 is not shown) to be connected to each other. The housing 11 has an outer peripheral cylindrical portion 11b partially cut away and a filter holding portion 11c on the optical axis, and a low-pass filter 11d is fixed to the filter holding portion 11c. The low-pass filter 11d is located in front of the solid-state imaging device 10a on the substrate 10 fixed in the camera body.
[0009]
The fixed ring 13 is located inside the outer peripheral cylindrical portion 11 b of the housing 11. The rotating ring 14 is located on the outer peripheral side of the fixed ring 13 (between the stationary ring 13 and the outer cylindrical portion 11b), and the cam ring 15 is located on the inner peripheral side. A cam ring regulating cam groove 13b (three at equal angular intervals in the circumferential direction) is formed as a through groove in the fixed ring 13, and the thickness of the rear end portion of the cam ring 15 is formed in the cam ring regulating cam groove 13b. A follower pin 15b fixed radially outwardly is fitted into the meat portion 15a. On the other hand, a rotation transmitting groove 14a for fitting the follower pin 15b is formed on the inner peripheral surface of the rotating ring 14.
[0010]
FIG. 11 shows a developed shape of the rotation transmitting groove 14a and the cam ring regulating cam groove 13b. The rotation transmission groove 14a is formed of a linear groove 14a1 parallel to the optical axis except for the base (the end on the camera body side), and the rotation transmission groove 14a and the inclined groove 14a2 that follow the linear groove 14a1 in the circumferential direction. And a groove 14a3. The circumferential groove 14a3 is a section for assembly. On the other hand, the cam ring regulating cam groove 13b includes a linear section 13b1 in a direction parallel to the optical axis of the base, a shooting state transition groove section 13b2 including an optical axis direction component and a circumferential direction component, and a zoom section including only a circumferential direction component. And a groove 13b3. The groove 13b4 exceeding the zoom section groove 13b3 is an assembly section.
[0011]
The rotary ring 14 rotates between the storage position in FIG. 11 and the preparation section and the zoom section. That is, in FIG. 11, since the rotating ring 14 rotates with respect to the fixed ring 13 which is fixed, the follower pin 15b is fitted into the base of the inclined groove 14a2 and the linear groove 13b1 (the storage position, the cam ring 15). When the rotary ring 14 rotates in a state in which it is most retracted, the follower pin 15b (cam ring 15) is pushed by the inclined groove portion 14a2 and moves in the optical axis direction without rotating according to the linear groove portion 13b1. When the rotating ring 14 rotates in a state where the follower pin 15b is fitted in the linear groove portion 14a1 and the photographing state transition groove portion 13b2 (preparation section), the follower pin 15b (cam ring 15) moves in the optical axis direction according to the photographing state transition groove portion 13b2. It rotates with it. When the rotating ring 14 rotates in a state in which the follower pin 15b is fitted in the linear groove 14a1 and the zoom section groove 13b3 (zoom section), the follower pin 15b (cam ring 15) moves in the optical axis direction according to the zoom section groove 13b3. Rotate without.
[0012]
A gear 14b is formed on the outer peripheral surface of the rotating ring 14, and the gear 14b meshes with a pinion (not shown). The pinion is driven in the forward / reverse direction by a forward / reverse drive motor, and the cam ring 15 moves in the direction of the optical axis while rotating in the relationship shown in FIG. The operation of the cam ring 15 associated with the rotation of the rotary ring 14 described above is based on the state in which the cam ring 15 is most retracted, first only goes straight (straight groove portion 13b1), and moves in the optical axis direction with the rotation ( The shooting state transition groove 13b2, the preparation section), and finally only the rotation (zoom section groove 13b3, zoom section).
[0013]
In the zoom lens barrel according to the present embodiment, the rotating members are the rotating ring 14, the cam ring 15, and a barrier opening / closing ring 31, which will be described later, and the other members move straight only in the optical axis direction without rotating. (However, the second group moving frame 19 slightly rotates as described later). Next, these rectilinear members and their guide mechanisms will be described. An outer lens frame ring (straight guide ring) 16 and an inner lens frame ring (straight guide ring) 17 are located between the fixed ring 13 and the cam ring 15 in order from the outside. The thick portion 15a of the cam ring 15 secures an annular space between the cam ring 15 and the fixed ring 13 for sandwiching the thin outer lens frame ring 16 and the inner lens frame ring 17. 15a is rotatably engaged with the inner peripheral surface of the fixed ring 13 so as not to cause harmful fall.
[0014]
The outer lens frame ring 16 located just inside the fixed ring 13 is composed of a lens frame ring body 16r made of synthetic resin and a metal reinforcing ring 16x, and has a thick rear end portion of the lens frame ring body 16r. The straight guide keys 16b (three at equal angular intervals in the circumferential direction) are formed on the portion 16a so as to protrude radially outward. On the inner surface of the fixed ring 13, there is formed a rectilinear guide groove 13c parallel to the optical axis for slidably fitting the rectilinear guide key 16b. The metal reinforcing annular body 16x is bonded and fixed to the front outer peripheral surface of the thick portion 16a at the rear end of the lens barrel ring body 16r, thereby reducing the thickness of the outer lens barrel ring 16 and, consequently, the overall thickness of the zoom lens barrel. (Reducing the diameter).
[0015]
Like the outer lens frame ring 16, the inner lens frame ring 17 includes a lens frame ring main body 17r made of synthetic resin and a metal reinforcing ring 17x. The metal reinforcing ring 17x is bonded and fixed to the front outer peripheral surface of the thick part 17a at the rear end of the lens barrel ring body 17r, so that the thickness of the inner lens barrel ring 17 and the thickness of the entire zoom lens barrel are reduced ( Diameter).
[0016]
On the inner surface of the outer lens frame ring 16 (the lens frame ring body 16r), straight guide grooves 16c (three at equal angular intervals in the circumferential direction) parallel to the optical axis are formed. A linear guide key 17b protruding from a thick portion 17a at the rear end of the lens frame ring body 17r is slidably fitted. A plurality of bayonet claws 16d projecting inward in the radial direction are formed at the rear end of the outer lens frame ring 16 (the lens frame ring main body 16r). In addition, an annular groove 15c is formed to hold the bayonet claw 16d rotatably at a specific angle position. Due to the relationship between the bayonet claw 16d and the annular groove 15c, the cam ring 15 and the outer lens frame ring 16 are coupled so that they can be freely rotated relative to each other and move together in the optical axis direction without being separated at the used rotation position. are doing.
[0017]
Further, an inner flange 17c is formed in front of the inner lens frame ring 17 (the lens frame ring main body 17r).17cWill be described laterBarrierThe block 40 and the barrier opening / closing ring 31 are fixed. On the back surface of the inner flange 17c, straight guide bosses 17d (three at equal angular intervals in the circumferential direction) are formed which are oriented in a direction parallel to the optical axis. On the other hand, this inner mirror frame ring 17WithinThe first group moving frame 18 is positioned on the side, and the straight guide boss 17d is slidably fitted in a portion of the inner flange 18b other than the lens opening and the female screw portion 18d (described later). Straight guide holes 18a (three at equal angular intervals in the circumferential direction) are formed (FIG. 6). The straight guide hole 18a is formed as an oval hole that is long in the radial direction. In the fitting gap between the rectilinear guide boss 17d and the rectilinear guide hole 18a, the first group moving frame 18 is fitted to the inner peripheral surface of the cam ring 15 (described later) even with a slight clearance (play). Therefore, it is possible to guide the vehicle straight ahead with sufficient accuracy. On the inner surface of the first group moving frame 18, straight guide grooves 18c (three at equal angular intervals in the circumferential direction) are formed in a direction parallel to the optical axis.
[0018]
A second group moving frame 19 is fitted on the inner surface of the first group moving frame 18. A linear guide key 19a that fits into the linear guide groove 18c of the first group moving frame 18 is formed on the outer periphery of the distal end portion of the second group moving frame 19.
[0019]
The above-mentioned fitting relationship and straight-movement guide relationship are as follows: the outer lens frame ring 16 is guided straight to the fixed ring 13, the inner lens frame ring 17 is guided straight to the outer lens frame ring 16, and the first-group moving frame in this order from the outer peripheral side. 18 can be regarded as being guided straight to the inner lens frame ring 17, and the second group moving frame 19 can be regarded as being linearly guided to the first group moving frame 18, and the inner lens frame ring 17 and the first group moving frame 18 Is carried out from the front by a relationship between a rectilinear guide boss 17d protruding rearward from the front of the inner lens frame ring 17 and a rectilinear guide hole 18a of the first group moving frame 18. For this reason, there is no need to interpose another linear guide member inside and outside the cam ring 15, and the annular space between the inner lens frame ring 17 and the first-group moving frame 18 can be reduced, and the diameter can be reduced.
[0020]
The first group moving frame 18 is formed with a female screw portion 18d for screwing the first group fixing frame 20 to which the first lens group L1 is fixed. The screwing position of the first group fixing frame 20 with respect to the female screw portion 18d is adjusted at the time of assembling, and after the adjustment, it is adhesively fixed. A shutter block 21 is inserted into the annular concave portion 19b of the second group moving frame 19, and the shutter block 21 is fixed to the second group moving frame 19 by screws (not shown). The light-shielding ring (sliding sheet holding ring) 19 c is fitted and fixed to the second group moving frame 19. The second lens unit L2 is located at the center of the shutter block 21, and is fixed to the second unit moving frame 19 via the lens pressing frame 19d. After adjusting the position of the second lens group L2 with respect to the second-group moving frame 19, the lens holding frame 19d is adhered and fixed. The shutter block 21 opens and closes the shutter blade 21a according to subject brightness information. As shown in FIG. 7, a flexible printed circuit board (FPC board) 21b that gives an operation signal to the shutter block 21 is guided backward from the block 21 and then folded forward, and furthermore, a part of the fixed ring 13. After being glued to the outer periphery of the fixed ring 13 from the guide portion 28 having a notch and folded back, it is guided to the outside of the housing 11. When the FPC board 21b is extended to the maximum, the front end of the FPC board 21b is folded forward by the elastic ring (rubber rubber) 29 whose front end is located behind the front end of the guide portion 28 and is locked by the hook 11f. The elastic ring 29 urges the FPC board 21b in a direction away from the optical axis, thereby preventing the FPC board 21b from sagging into the optical path in the photographing state.
[0021]
The third lens unit L3 is fixed to the third unit frame 22. As shown in FIG. 4, the third group frame 22 is movably held in the optical axis direction along a pair of linear guide rods 22 a having one end fixed to the shaft retainer 12 and the other end fixed to the housing 10. The movement is controlled in the optical axis direction according to the subject distance information by a feed screw 24 driven to rotate forward and backward by a stepping motor.
[0022]
Zooming is performed by the first lens unit L1 (the first unit moving frame 18).as well asThe second lens unit L2 (the second unit moving frame 19))It is performed by moving the air in the direction of the optical axis while changing the air gap between them. On the inner surface of the cam ring 15, there are formed lens group cam grooves C1 (three at the same angular interval in the circumferential direction). The first group moving frame 18 and the second group moving frame 19 whose rotation is restricted by the above-described straight guide relationship and can only move in the optical axis direction are moved by the lens group cam groove C1 with the rotation of the cam ring 15 along the optical axis. Move in the direction. 8 to 10 show the developed shape of the lens group cam groove C1. In FIG. 8, the lens group cam groove C1 on the inner surface of the cam ring 15 is drawn by a broken line as shown in FIGS. Are drawn with solid lines for clarity. The cam groove C1 for the lens group is formed by forming a cam profile for the first lens group L1 and a cam profile for the second lens group L2 in a continuous profile having a bottom, and a first lens group L1 and a second lens group. The storage position of L2 is characterized in that the first lens unit L1 and the second lens unit L2 are free, and can be stored close to the position where the lens frames come into contact with each other.
[0023]
That is, a first group follower pin 18f formed on the outer surface of the first group moving frame 18 (first lens group L1) and a second group follower pin 19f formed on the outer surface of the second group moving frame 19 (second lens group L2). Are fitted in the lens group cam groove C1. The lens group cam groove C1, which is one continuous groove, has a function of moving the first lens group L1 and the second lens group L2 along independent trajectories. In the conventional lens barrel, independent cam grooves are required by the number of lens groups to be moved along independent trajectories.
[0024]
The cam groove C1 for the lens group according to the present embodiment includes a zoom section C1Z1 for the first group, a zoom section C1Z2 for the second group, and a storage space for the first group in order from the insertion end C1e of the follower pin 18f for the first group and the follower pin 19f for the second group. C1A1, a second group storage plaza C1A2. Both ends of the first group zoom section C1Z1 are the first group tele position Z1T and the first group wide position Z1W, and both ends of the second group zoom section C1Z2 are the second group tele position Z2T and the second group wide position Z2W. is there. As shown, the first-group storage plaza C1A1 and the second-group storage plaza C1A2 are formed such that the groove width in a direction parallel to the optical axis (left-right direction in the drawing) is wider than grooves in other sections. The first group follower pin 18f has a space in which the second group follower pin 19f can freely move. That is, the first group storage plaza C1A1 has a shape that is long in the circumferential direction of the cam ring, and the first group follower pin 18f can move in the optical axis direction by a screwing adjustment dimension of the first group fixed frame 20 with respect to the first group moving frame 18. Has a good clearance. The second group storage space C1A2 has a substantially triangular shape, and has a clearance such that the follower pin 19f for the second group can largely move in the circumferential direction of the cam ring and in the optical axis direction.
[0025]
The first-group follower pin 18f of the first-group moving frame 18 and the second-group follower pin 19f of the second-group moving frame 19 are respectively located in the first-group storage plaza C1A1 and the second-group storage plaza C1A2 at the storage rotation position of the cam ring 15. So that the phase in the circumferential direction is determined. The first group storage plaza C1A1 and the second group storage plaza C1A2 do not restrain the first group follower pin 18f and the second group follower pin 19f. That is, the first group follower pin 18f and the second group follower pin 19f can move in the optical axis direction in the first group storage plaza C1A1 and the second group storage plaza C1A2, and the storage length can be minimized by this clearance. . The first group storage plaza C1A1 is provided with a clearance capable of sufficiently absorbing a change in position when the follower pin 18f is stored by adjusting the screwing position of the first group frame 20 with the female screw portion 18d.
[0026]
A spring center projection 17g (FIGS. 5 and 7) is formed on the inner flange 17c of the inner lens frame ring 17 at a circumferential position different from that of the rectilinear guide boss 17d. A spring housing recess 18g is formed in the side flange 18b so as to correspond to the spring center projection 17g. A compression spring 30 is inserted between the spring center protrusion 17g and the spring storage recess 18g to urge the first group moving frame 18 to move backward. For this reason, the first-group fixed frame 20 supported by the first-group moving frame 18 is moved by the clearance existing between the first-group follower pin 18f and the first-group storage plaza C1A1. ) Can be retracted to the mechanical position where it abuts. This mechanical contact position is indicated by the symbol P in FIGS. The second-group moving frame 19 can be retracted to a mechanical position in contact with the third-group frame 22 by the clearance existing between the second-group follower pin 19f and the second-group storage plaza C1A2. This mechanical contact position is indicated by the symbol Q in FIGS. For this reason, the storage length can be reduced as compared with the conventional device in which the storage positions of the first lens unit L1 and the second lens unit L2 are strictly defined by the cam grooves. Further, the third group frame 22 includes a feed screw24The spring 23 pressing against the nut attached to the housing can be retracted to a position where the spring 23 mechanically contacts the housing 11. This mechanical contact position is indicated by the symbol R in FIGS. The upper half of FIGS. 5, 6, and 7 shows the storage positions where the first group fixed frame 20, the second group moving frame 19 (light blocking ring 19c), the third group frame 22, and the housing 11 are in mechanical contact. I have. Note that the position of the first-group fixed frame 20 with respect to the first-group movable frame 18 fluctuates due to adjustment at the time of assembly, and the amount of rearward movement of the first-group fixed frame 20 depends on the position of the first-group fixed frame 20. At the time of storage, the adjustment amount is absorbed by the spring 30, and the lens barrel in which the contact position shown by PQR can be stored can be stored.
[0027]
When the cam ring 15 rotates from the storage rotation position to the photographing position, the first group follower pin 18f in the first group storage plaza C1A1 reaches the first group zoom section C1Z1 through the second group zoom section C1Z2. The second group follower pin 19f extends from the second group storage plaza C1A2 to the second group zoom section C1Z2 through the first group storage plaza C1A1. As described above, the follower pin 19f for the second group is used.(Second lens group L2)For the first group follower pin 18f (first lens group L1), the second group zoom section C1Z2 is merely a pass section from the storage position to the shooting position (zoom section). It is useful for reducing and facilitating placement and reducing the slope.
[0028]
The inner lens frame ring 17 moves in the optical axis direction independently of the first-group moving frame 18, but with a locus substantially similar to that of the first-group moving frame 18. Therefore, on the outer surface of the cam ring 15, there are provided lens frame ring cam grooves C2 (FIG. 8, three at equal angular intervals in the circumferential direction) for moving the inner lens frame ring 17 guided straight forward and backward in the optical axis direction. A follower pin 17f (FIG. 8) protruding from the inner surface of the inner lens frame ring 17 is formed in the lens frame ring cam groove C2.I'm stuck.The developed shape of the cam groove C2 is the same as that of the lens group cam groove C1.SimilarAs shown in FIG. 8, the first section has a zoom section corresponding section C2Z1, a second group zoom section corresponding section C2Z2, and a barrier opening / closing section C2B in order from the insertion end C2e of the follower pin 17f. The barrier opening / closing section C2B is a circumferential groove, and the cam ring 15 and the inner lens frame ring 17 rotate only relative to each other. As is apparent from FIG. 8, the lens group cam groove C1 and the lens frame ring cam groove C2 of the cam ring 15 are slightly displaced from each other in the optical axis direction and fit into the lens frame ring cam groove C2. The follower pin 17f of the inner lens frame ring 17 and the follower pin 18f of the first group moving frame 18 fitted in the lens group cam groove C1 are arranged in a direction parallel to the optical axis.
[0029]
In this way, the outer lens frame ring 17 exposed to the exterior is guided in the optical axis direction by a different cam mechanism as a member separate from the first group moving frame 18 so that the external force applied to the inner lens frame ring 17 moves by one group. Transmission from the frame 18 to the first lens unit L1 can be prevented, and deterioration of the optical performance of the zoom lens due to a shift of the optical axis of the first lens unit L1 can be prevented. Also, the shape of the cam ring 15 isResembleSince the cam groove C1 for the lens group and the cam groove C2 for the lens frame ring are slightly displaced in the optical axis direction, the thickness of the cam ring 15 does not increase and the diameter applied to the inner lens frame ring 17 is increased. A force inward in the direction can be received by the first group moving frame 18 via the first group follower pin 18f. Further, the follower pin 17f fitted in the lens frame ring cam groove C2 and the follower pin 18f fitted in the lens group cam groove C1 are arranged in a direction parallel to the optical axis. The first group moving frame 18 which is biased to moveInner mirror frame ring 17And the spring force that acts between them hardly changes depending on the relative rotational position of the cam ring 15.
[0030]
A barrier block 40 is inserted and fixed to the inner surface of the reinforcing annular body 17x of the inner lens frame ring 17, and the barrier opening / closing ring 31 rotates between the barrier block 40 and the inner flange 17c of the inner lens frame ring 17. It is freely supported. A notch 15k is formed in the cam ring 15, and when the cam ring 15 rotates in the barrier opening / closing section C2B, the end face of the notch 15k contacts the driven surface 31a of the barrier opening / closing ring 31 to rotate. And a rotation transmitting surface 15d in a direction parallel to the optical axis. As shown in FIG. 8, the notch 15k is formed in a region of the cam ring 15 except for the region where the cam grooves C1 and C2 are formed.
[0031]
As shown in FIGS. 2 and 14, the barrier block 40 is rotatably supported by a barrier support frame 41 having a photographing opening 41a in the center and a pair of rotation center bosses 41b formed in the barrier support frame 41. A pair of barrier plates 42, a barrier closing spring (torsion spring) 43 for urging the pair of barrier plates 42 in the closing direction, and a barrier mounting for supporting the barrier plate 42 and the barrier closing spring 43 between the barrier support frame 41. It is composed of a plate 44 and is sub-assembled as a separate unit in advance. Barrier bosses 42 a (FIG. 12, FIG. 13) provided on the pair of barrier plates 42 project toward the barrier opening / closing ring 31 from the escape grooves 44 a formed in the barrier mounting plate 44. The barrier opening / closing ring 31 is formed with a pair of opening / closing projections 31c that engage with the pair of barrier bosses 42a. FIG. 12 and FIG.Barrier plate 42To the virtual line (Chain line), Showing a state in which the barrier opening / closing ring 31 closes the barrier (FIG. 12) and a state in which the barrier opening / closing ring 31 is open (FIG. 13). FIG. 14 is a diagram when the barrier block is attached with the barrier support frame 41 removed.
[0032]
The barrier opening / closing ring 31 is extended in the barrier opening direction by a tension spring 45 that is stronger than the barrier closing spring 43 and is stretched between a spring hook projection 31 b formed on itself and a spring hook projection 17 h formed on the inner lens frame ring 17. It is biased to rotate. The opening / closing projection 31c of the barrier opening / closing ring 31 contacts the barrier boss 42a at the rotation biasing end of the tension spring 45 to open the barrier plate 42 (FIG. 13). On the other hand, when the barrier opening / closing ring 31 is rotated against the force of the tension spring 45, the opening / closing projection 31c separates from the barrier boss 42a, and the pair of barrier plates 42 are closed by the force of the barrier closing spring 43 (FIG. 12). ).
[0033]
It is the rotation transmitting surface 15d formed on the cam ring 15 that rotates the barrier opening / closing ring 31 against the force of the tension spring 45. An end face of the notch 31k formed in the barrier opening / closing ring 31 is a driven face 31a. When the cam ring 15 is in the retracted position, the rotation transmitting surface 15 d of the cam ring 15 passes through an opening (not shown) formed in the inner flange 17 c of the inner lens frame ring 17 and the driven surface 31 a of the barrier opening / closing ring 31. , The barrier opening / closing ring 31 is rotated against the force of the tension spring 45, the barrier plate 42 is closed, and the cam ring 15 is moved relative to the inner lens frame ring 17 in the barrier opening / closing section C2B (FIG. 8). During relative rotation, the rotation transmission surface 15d is not in contact, and the barrier opening / closing ring 31 is urged by the force of the tension spring 45 to open the barrier plate 42.
[0034]
FIG. 16 shows the movement of the rotation transmitting surface 15d when the cam ring 15 reaches the preparation section from the storage position. The cam ring 15 rotates while moving in the optical axis direction according to the relationship between the cam ring regulating cam groove 13b of the fixed ring 13, the follower pin 15b, and the rotation transmitting groove 14a of the rotating ring 14 (FIG. 16).1, 2, 3, 4Position), then rotate only (same position)4,5). The rotation transmitting surface 15d is located in this section4From5When moving, the barrier plate 42 is opened apart from the driven surface 31a of the barrier opening / closing ring 31. Conversely, when the cam ring 15 reaches the storage position from the preparation section, the section of the rotation transmission surface 15 d5From4The barrier plate 42 is closed.
[0035]
The pair of barrier plates 42 is basically a flat plate, and has an inner surface corresponding to the curvature of the convex surface L1r of the lens surface closest to the object in the first lens unit L1, as shown in FIGS. An escape recess 42b is formed. The escape recess 42b allows the inner lens frame ring 17 to be retracted to the limit during storage. The relief recess 42b is formed by a molding die for molding the barrier plate 42 with resin.
[0036]
The above barrier block 40 is provided inside the reinforcing annular body 17x.Mirror frame ring body 17rAre fitted and adhered to each other, and are fitted into the opening at the distal end of the reinforcing annular body 17x, and are engaged with a hook (not shown) provided on the inner lens frame ring 17 to prevent the reinforcing annular body 17x from coming off. Have been. A barrier opening / closing ring 31 is rotatably supported between the barrier block 40 and the inner flange 17c of the inner lens frame ring 17. A notch 17k (FIG. 14) into which the barrier plate 42 in an open state enters is formed in the inner lens frame ring body 17r made of synthetic resin corresponding to the position of the barrier plate 42, and the outside of the notch 17k is formed. The reinforcing annular body 17x covers. By providing a metal reinforcing ring 17x separate from the lens frame ring main body 17r made of synthetic resin, a notch 17k penetrating through the main body 17r can be formed. If the barrier plates 42 of the barrier block 40 are stacked in a four-sheet configuration during storage, the radial length required for storage when the barrier is opened can be shortened, but the axial length is large and one or two barrier plates are required. If so, the axial length can be shortened, but there is an unavoidable problem that the radial length requires a large amount. By forming a notch 17k for barrier escape in the inner lens frame ring 17 as in this embodiment, the axial length of the two-barrier configuration can be shortened, and the radial direction of the inner lens frame ring 17 can be reduced. The effect that the increase in length can be suppressed is obtained.
[0037]
As described above, the zoom section groove 13b3 of the fixed ring 13 is a circumferential groove having no optical axis direction component, and the photographing area (zoom area) in which the follower pin 15b of the cam ring 15 moves in the zoom section groove 13b3. Then, the cam ring 15 rotates only. In this photographing area, an urging ring 32 is fitted to the tip of the rotating ring 14 in order to take backlash (play) between the follower pin 15b of the cam ring 15 and the zoom section groove 13b3. A spring hook projection 32a and a spring hook projection 14c are formed on the urging ring 32 and the rotary ring 14, respectively. A tension coil spring 33 is stretched between the spring hook projection 32a and the spring hook projection 14c. And biases the biasing ring 32 rearward. As shown in FIGS. 1 and 4, three (equally spaced in the circumferential direction) projections 32 c are provided at the rear end of the inner peripheral surface of the biasing ring 32, and the projections 32 c The three through holes 14 d provided at the front end of the rotary ring 14 penetrate the rotary ring 14 from outside to inside. The through hole 14d is provided immediately before the rotation transmitting groove 14a, and the projection 32c is located in front of the follower pin 15b fitted in the rotation transmitting groove 14a. When the follower pin 15b of the cam ring 15 reaches the zoom section groove 13b3 of the fixed ring 13, the contact end face 32b forming the rear end face of the projection 32c comes into contact with the follower pin 15b to move the follower pin 15b backward. To bring the follower pin 15b into contact with the rear surface of the zoom section groove 13b3.
[0038]
In the above description, a straight guide groove 18c is formed on the inner surface of the first group moving frame 18 in a direction parallel to the optical axis, and fits into the straight guide groove 18c on the outer surface of the distal end portion of the second group moving frame 19. Although the rectilinear guide key 19a is formed, in addition to the above-described configuration, the tip of the rectilinear guide groove 18c has, as shown in FIG. 18h, the straight guide key 19a (the second group moving frame 19) can be rotated within the rotation permitting portion 18h. The rotation area of the second-group moving frame 19 is when the second-group moving frame 19 reaches the vicinity of the storage position. The reason for allowing such rotation is as follows. In addition, when the linear guide key 19a of the second group moving frame 19 is located inside the rotation permitting portion 18h (when the second lens L2 is near the storage position), the second group is located on the inner flange 18b of the first group moving frame 18. A circumferential opening 18j (FIGS. 3 and 6) provided at the front end of the moving frame 19 and protruding forward from a protruding piece 19e including a rectilinear guide key 19a is formed. By making the straight guide key 19a protrude forward from the inner flange 18b, the storage length can be reduced.
[0039]
If the cam ring 15 rotates in the lens extension direction (the direction indicated by the arrow x in FIG. 10) in a state where the lens is stored and the first group follower pin 18f is located in the first group storage plaza C1A1, the first group. Since the follower pin 18f enters the second group zoom section C1Z2, the first group moving frame 18 moves forward in the optical axis direction. The movement positions of the first group follower pins 18f are shown as reference positions 1, 2, 3, and 4 in FIG.
On the other hand, when the cam ring 15 rotates in the x direction, the second group follower pin 19f located in the second group storage plaza C1A2 is left behind with respect to the cam ring 15 and becomes 1 in the second group storage plaza C1A2. It moves to the position 2 on the inclined edge β and contacts the inclined surface xx.
When the cam ring 15 further rotates in the x direction, the following optical axis direction component and circumferential component are mixed in the follower pin 19f for the second group according to the slope xx of the oblique edge β of the second group storage plaza C1A2. Exercise occurs.
The first group moving frame 18 moves forward in the optical axis, the side wall of the rotation permitting portion 18h is in contact with the straight guide key 19a, and the first group moving frame 18 is moved forward in the optical axis direction by the force of the second group moving frame. 19 is pushed forward on the optical axis and rotates as the cam follower 19f moves from the position 2 to the position 3 along the slope XX. That is, the rectilinear guide key 19a moves toward the rectilinear guide groove 18c while sliding on the side wall of the rotation permitting portion 18h.
As described above, when the second-group moving frame 19 is relatively rotated with respect to the first-group moving frame 18, the first-group moving frame 18 can smoothly move forward without interfering with the second-group moving frame 19.
[0040]
Eventually,Straight ahead guide key 19aIs a straight guide groove18cThe rotation stops when it comes into contact with one wall of the first group, and it is ready to enter the straight guide groove 18c of the first group moving frame 18 that advances along the optical axis direction (position 3). As the vehicle advances, the straight guide key 19a enters the straight guide groove 18c. After the rectilinear guide key 19a enters the rectilinear guide groove 18c, the rotation of the second group moving frame 19 is restrained, and the second group follower pin 19f moves from the position of 3 to the position of 4 at the inclined edge β. The second group frame 19 moves straight on the slope xx in the direction opposite to the moving direction of the first group frame (position 4). When the cam ring 15 further rotates, the follower pin 19f for the second group enters the first-group storage space C1A1 in the end, and in the subsequent rotation of the cam ring 15 in the x direction, the first group moves according to each section of the cam groove C1 for the lens group. The frame 18 and the second group moving frame 19 move straight in the optical axis direction (the second group moving frame 19 is guided straight to the first group moving frame 18). In this manner, the substantially triangular second group storage plaza C1A2 not only secures a clearance for releasing the position regulation of the follower pin 19f in the optical axis direction during storage, but also forms an oblique edge β, The second-group moving frame 19 is rotated to guide the rectilinear guide key 19a to the rectilinear guide groove 18c to a position where it can be engaged, and to move the first-group frame 18 and the second-group frame 19 in opposite directions in the optical axis direction. It has a function of moving the two to ensure the engagement between them.
[0041]
On the other hand, when the cam ring 15 rotates in the storage direction (the direction opposite to the arrow x in FIG. 10) from the photographing state, the follower pin 18f and the follower pin 19f return to the first group storage square C1A1 and the second group storage square C1A2, respectively. Here, the movement of the follower pin 19f will be specifically described. After the follower pin 19f has passed through the first group storage plaza C1A1, along the bottom edge α shown in FIG. 9 of the second group storage plaza C1A2 in FIG.RightMove towards. Eventually, when the follower pin 19f comes to a position slightly before the end point α1 of the bottom edge portion α, the straight guide key 19a comes off the straight guide groove 18c and reaches the rotation permitting portion 18h, and the second group moving frame 19 is moved to the first group moving frame. 18 is in a state where it can be relatively rotated. Thereafter, the follower pin 19f reaches the end point α1, and rotates integrally with the cam ring 15 around the lens optical axis, that is, the second group moving frame 19 relatively rotates with the first group moving frame 18. Then, the follower pin 15b of the cam ring 15Straight grooveGuided by 13b1, the cam ring 15 retreats in the optical axis direction (moves rightward in FIG. 9), so that the follower pin 19f is finally located at the end point α2 in FIG. In this way, the first group moving frame 18 and the second group moving frame 19 move smoothly to the respective storage positions.
Assuming a configuration in which the second group moving frame 19 is moved to the storage position only by the straight guide just like the first group moving frame 18, the cam groove C1 is set in the circumferential direction of the cam ring 15 (that is, above the end point α1 in FIG. 9). Must be formed longer, but if it is left as it is, it will interfere with other formed cam grooves. In order to avoid interference, the diameter of the cam ring 15 must be increased. However, according to the above embodiment, the cam groove for storing the second group moving frame 19 can be set short in the circumferential direction of the cam ring as long as it does not interfere with the other cam grooves. it can.
[0042]
The two-group storage plaza C1A2 is formed in a substantially triangular shape as shown in the drawing, so that if it is formed in a straight line, the lens group cam groove C1, which is longer, can be made shorter. By shortening the cam groove C1 for the lens group, it is possible to form the three cam grooves C1 for the lens group on the cam ring 15 at a gentle inclination angle. Further, since the second group storage space C1A2 having such a shape is provided, when the first group follower pin 18f and the second group follower pin 19f move forward from the storage position in the optical axis direction, the second group follower pin 19f is stored in the second group. The inside of the square C1A2 moves in the order of 1, 2, 3, and 4 in FIG.Become.
[0043]
FIG. 15 shows the cam ring of the second group moving frame 19.Fifteen3 shows a state of rotation with respect to. The first group moving frame 18 is provided with a cam groove for the lens group.C1By cam ringFifteen15, the second group moving frame 19 is relatively rotated with respect to the cam ring in the section R of FIG.
[0044]
As described above, when the first group moving frame 18 and the second group moving frame 19 are relatively rotated at the storage position, the first group fixed frame 20 and the second group moving frame 19 (the light blocking ring 19c) supported by the first group moving frame 18 are moved. Is mechanically in contact with the contact position P at the storage position, so that frictional resistance is a problem. In particular, since the first-group fixed frame 20 is screwed to the female screw portion 18d of the first-group moving frame 18, there is a possibility that the first-group fixed frame 20 is rotated and the position in the optical axis direction is deviated. Therefore, a low friction sheet, for example, a sliding sheet 26 made of a tetrafluoroethylene resin is supported on the light-shielding ring 19c, and the rear end face of the first group fixing frame 20 is brought into contact with the sliding sheet 26 (FIG. 5, 6, 7).
[0045]
The entire operation from the storage position of the present zoom lens barrel having the above configuration to the photographing position (zoom position) is as follows. In the storage position, the first-group moving frame 18 urged to move rearward by the force of the compression spring 30 is moved.The first group fixed frame 20 to supportMechanical position abutting on the second-group moving frame 19 (light-shielding ring 19c) due to the clearance existing between the first-group follower pin 18f and the first-group storage plaza C1A1.PThe second-group moving frame 19 is retracted to the mechanical position where the second-group moving frame 19 comes into contact with the third-group frame 22 by the clearance existing between the second-group follower pin 19f and the second-group storage plaza C1A2.QThe third group frame 22 is located at a position where the spring 23 pressing against the nut attached to the feed screw contracts and mechanically contacts the housing 11.RHas receded until. Due to these mechanical contacts, the storage length is reduced. In this storage position, the rotation transmitting surface 15d of the cam ring 15 pushes the driven surface 31a to rotate the barrier opening / closing ring 31 in the barrier closing direction against the force of the tension spring 45, and the opening / closing projection 31c is moved from the barrier boss 42a. Since they are separated, the barrier plate 42 closes the photographing opening 41a (FIG. 12).
[0046]
The rotating ring 14 extends the lens from this stored state.In the directionWhen rotated, the cam ring 15 having the follower pin 15b moves only linearly by the straight groove portion 13b1 of the fixed ring 13 and the inclined groove portion 14a2 of the rotating ring 14. Then, the followers 18f and 19f located in the storage plazas C1A1 and C1A2 of the lens group cam groove C1 are moved by the cam grooves.C1ofRimMoved forward by being pushed by, resulting in mechanical contact1 group fixed frame 20And the second-group moving frame 19 (light-shielding ring 19c) move straight and release mechanical contact with each other, and the mechanical contact between the second-group moving frame 19 and the third-group frame 22 is released.
[0047]
When the rotating ring 14 further rotates in the lens extension direction, the cam ring 15 moves in the optical axis direction with the rotation by the shooting state transition groove 13b2 of the fixed ring 13, and eventually reaches the zoom section groove 13b3. At the initial stage of rotation of the cam ring 15 by the photographing state transition groove 13b2, the rotation transmitting surface 15d of the cam ring 15 separates from the driven surface 31a of the barrier opening / closing ring 31, and the barrier opening / closing ring 31 is moved by the force of the tension spring 45. It turns in the opening direction and opens the barrier plate 42 against the force of the barrier closing spring 43. Before and after the barrier opening operation,Second group moving frame 19ButFirst group moving frame 18, The first-group fixed frame 20 slides on the sliding sheet 26.
[0048]
Next, when the follower pin 15b of the cam ring 15 reaches the zoom section groove 13b3 by the rotation of the rotating ring 14 in the same direction, the urging ring 32Of each projection 32cThe contact end face 32b at the rear end contacts the follower pin 15b. The urging ring 32 is a tension spring33Therefore, the follower pin 15b is brought into contact with the rear surface of the zoom section groove 13b3 via the contact end surface 32b. This relationship is maintained while the follower pin 15b is located in the zoom section groove 13b3. As long as the cam ring 15 is rotated in the zoom section of FIG. Backlash for the ring 13 is eliminated.
[0049]
When the cam ring 15 rotates from the storage rotation position to the zoom section via the preparation section as described above, the first group follower pin 18f in the first group storage plaza C1A1 of the cam ring 15 moves the second group zoom section C1Z2. Thus, the first group zoom section C1Z1 is reached, and the second group follower pin 19f reaches the second group zoom section C1Z2. When the cam ring 15 rotates within the zoom sections C1Z1 and C2Z2, the first group moving frame 18 (first lens group L1) and the second group moving frame 19 (second lens group L2) move to predetermined positions in the optical axis direction according to the cam profile. And the combined focal length with the third lens unit L3 changes. This zooming is performed by a well-known zoom switch (not shown). When the shutter release button is pressed, the stepping motor rotates by an angle (number of rotations) corresponding to the subject distance information, and moves the third lens unit L3 (third group frame 22) as the focus lens unit in the optical axis direction. And focus on the subject. Further, the shutter block 21 opens and closes the shutter blade 21a according to the subject luminance information.
[0050]
When the first-group moving frame 18 moves straight, the inner lens frame ring 17 is connected to the first-group moving frame 18 by a cam groove C2 having a shape similar to the cam groove C1 that regulates the position of the first-group moving frame 18. Move in the optical axis direction without changing the relative position of. The outer lens frame ring 16 always moves together with the cam ring 15 in the optical axis direction due to the relationship between the bayonet claw 16d and the annular groove 15c. Both the frame rings 17 move straight in the optical axis direction.
[0051]
When the cam ring 15 rotates from the zoom section in the direction of the storage position, the outer lens frame ring 16 and the inner lens frame ring 17 both move rearward in the optical axis direction by the reverse operation, and the first-group moving frame 18 ( The first lens unit L1) is1st group fixed frame 20 to supportAnd the second group moving frame 19 (the second lens group L2) are located at the retracted ends of the compression springs 30 and are in contact with each other, and the second group moving frame 19 is in mechanical contact with the third group frame 22 and has a feed screw.24By the spring 23 pressing against the nut attached to3rd group frame 22It retreats until it hits filter holding part 11c. Further, the rotation transmitting surface 15d of the cam ring 15 pushes the driven surface 31a to rotate the barrier opening / closing ring 31 in the barrier closing direction against the force of the tension spring 45, and the barrier plate 42 closes the photographing opening 41a.
[0052]
[Description of features of the present invention]
A characteristic part of the present invention is a cam ring supported so as to cause movement in the optical axis direction with rotation, and a movement supported on the inner peripheral side of the cam ring so as to restrict rotation and allow linear movement in the optical axis direction. A lens group frame, a lens group cam groove formed on the inner peripheral surface of the cam ring, and a follower pin provided on the movable lens group frame that fits into the lens group cam groove. A lens group cam mechanism for moving the movable lens group frame in the optical axis direction, a lens frame ring supported on the outer peripheral side of the cam ring so as to restrict rotation and allow linear movement in the optical axis direction, and the cam A lens frame ring cam groove formed on the outer peripheral surface of the ring; and a follower pin provided on the lens frame ring to be fitted into the lens frame ring cam groove. A lens frame cam mechanism for moving the lens group in the axial direction; The ring cam groove has substantially the same shape with different positions in the optical axis direction in a region where the movable lens group frame advances and retreats in the optical axis direction, and has a follower pin of the movable lens group frame and a follower pin of the lens frame ring. Are located on substantially the same axis in a direction parallel to the optical axis, and further, spring means for urging the movable lens group frame and the lens frame ring toward or away from each other in the optical axis direction. In that it has
Hereinafter, this characteristic portion will be described.
The lens group cam mechanism of the present embodiment includes a lens group cam groove C1, a follower pin 18f, a rectilinear guide boss 17d, and a rectilinear guide hole 18a. It is composed of a cam groove C2, a follower pin 17f, a straight guide key 17b, and a straight guide groove 16c.
[0053]
The fixed ring 13 is located inside the outer peripheral cylindrical portion 11 b of the housing 11. The rotating ring 14 is located on the outer peripheral side of the fixed ring 13 (between the stationary ring 13 and the outer cylindrical portion 11b), and the cam ring 15 is located on the inner peripheral side. The stationary ring 13 is formed with a rotating ring regulating cam groove 13b (three at equal angular intervals in the circumferential direction) as a through groove, and the rotating ring regulating cam groove 13b is formed on the outer circumferential surface of the cam ring 15 in the radial direction. A follower pin 15a fixed outward is fitted. On the other hand, a rotation transmitting groove 14a for fitting the follower pin 15a is formed on the inner peripheral surface of the rotating ring 14.
[0054]
A gear 14b is formed on the outer peripheral surface of the rotating ring 14, and the gear 14b meshes with a pinion (not shown). The pinion is driven in the forward / reverse direction by a forward / reverse drive motor, and the cam ring 15 moves in the direction of the optical axis while rotating in the relationship shown in FIG.
[0055]
The outer lens frame ring 16 located just inside the fixed ring 13 is composed of a lens frame ring body 16r made of synthetic resin and a metal reinforcing ring 16x, and has a thick rear end portion of the lens frame ring body 16r. The straight guide keys 16b (three at equal angular intervals in the circumferential direction) are formed on the portion 16a so as to protrude radially outward. On the inner surface of the fixed ring 13, there is formed a rectilinear guide groove 13c parallel to the optical axis for slidably fitting the rectilinear guide key 16b.
[0056]
The inner lens frame ring 17 (mirror frame ring), like the outer lens frame ring 16, includes a lens frame ring main body 17r made of synthetic resin and a metal reinforcing ring 17x.
[0057]
On the inner surface of the outer lens frame ring 16 (the lens frame ring body 16r), straight guide grooves 16c (three at equal angular intervals in the circumferential direction) parallel to the optical axis are formed. A linear guide key 17b protruding from a thick portion 17a at the rear end of the lens frame ring body 17r is slidably fitted. A plurality of bayonet claws 16d projecting inward in the radial direction are formed at the rear end of the outer lens frame ring 16 (the lens frame ring main body 16r). Further, an annular groove 15b is formed to hold the bayonet claw 16d rotatably at a specific angle position. Due to the relationship between the bayonet claw 16d and the annular groove 15b, the cam ring 15 and the outer lens frame ring 16 are coupled so that they can be freely rotated relative to each other and move together in the optical axis direction without being separated at the use rotation position. are doing.
[0058]
Further, an inner flange 17c is formed in front of the inner lens frame ring 17 (mirror frame ring main body 17r), and a rectilinear guide boss facing a direction parallel to the optical axis is provided on the back surface of the inner flange 17c. 17d (three at equal angular intervals in the circumferential direction) are formed. On the other hand, this inner mirror frame ring 17InsideIs provided with a first group moving frame 18 and straight guide holes 18a (three at equal angular intervals in the circumferential direction) into which the straight guide boss 17d is slidably fitted are formed in the inner flange 18b. (FIG. 6).
On the inner surface of the first group moving frame 18, straight guide grooves 18c (three at equal angular intervals in the circumferential direction) are formed in a direction parallel to the optical axis.
[0059]
A second group moving frame 19 is fitted on the inner surface of the first group moving frame 18. A linear guide key 19a that fits into the linear guide groove 18c of the first group moving frame 18 is formed on the outer periphery of the distal end portion of the second group moving frame 19.
[0060]
Zooming is performed by the first lens unit L1 (the first unit moving frame 18).as well asThis is performed by moving the second lens unit L2 (the second unit moving frame 19) forward and backward in the optical axis direction while changing the air gap between each other. On the inner surface of the cam ring 15, there are formed lens group cam grooves C1 (three at the same angular interval in the circumferential direction). The first group moving frame (moving lens group frame) 18 and the second group moving frame 19, whose rotation is restricted by the above-described straight guide relationship and can be moved only in the optical axis direction, are formed by the lens group cam groove C1 so that the cam ring 15 is moved. It moves in the optical axis direction as it rotates. The cam groove C1 for the lens group forms a cam profile for the first lens group L1 and a cam profile for the second lens group L2 in a continuous profile.
[0061]
That is, a first group follower pin 18f formed on the outer surface of the first group moving frame 18 (first lens group L1) and a second group follower pin 19f formed on the outer surface of the second group moving frame 19 (second lens group L2). Are fitted in the lens group cam groove C1. The lens group cam groove C1, which is one continuous groove, has a function of moving the first lens group L1 and the second lens group L2 along independent trajectories.
[0062]
A compression spring 30 is inserted between the spring center projection 17g (FIGS. 5 and 7) of the inner flange 17c of the inner lens frame ring 17 and the spring storage recess 18g of the first group moving frame 18, and the first group The moving frame 18 and the inner lens frame ring 17 are urged away from each other.
[0063]
The inner lens frame ring 17 moves in the optical axis direction independently of the first-group moving frame 18, but with a locus substantially similar to that of the first-group moving frame 18. Therefore, on the outer surface of the cam ring 15, there are provided lens frame ring cam grooves C2 (FIG. 8, three at equal angular intervals in the circumferential direction) for moving the inner lens frame ring 17 guided straight forward and backward in the optical axis direction. A follower pin 17f (FIG. 8) projecting from the inner surface of the inner lens frame ring 17 is fitted into the lens frame ring cam groove C2.
[0064]
The developed shape of the lens frame ring cam groove C2 is the same as the lens group cam groove C1.SimilarAs is clear from FIG. 8, the lens group cam groove C1 and the lens frame ring cam groove C2 of the cam ring 15 are slightly displaced in the optical axis direction, and fit into the lens frame ring cam groove C2. The follower pin 17f of the group moving frame 17 and the follower pin 18f of the second group moving frame 18 fitted in the lens group cam groove C1 are arranged in a direction parallel to the optical axis.
[0065]
When the rotary ring 14 rotates, the cam ring 15 rotates, and the follower pins 17f, 18f, and 19f engaged with the lens group cam groove C1 and the lens frame ring cam groove C2 of the cam ring 15 move in the optical axis direction. The inner lens frame ring 17, the first lens unit L1, and the second lens unit L2 move in the optical axis direction.
[0066]
According to this embodiment, the shape of the cam ring 15 isResembleThe cam groove C1 for the lens group and the cam groove C2 for the lens frame ring are provided on the cam ring 15 with their positions slightly shifted in the optical axis direction, and a follower pin 17f fitted into the cam groove C2 for the lens frame ring and a lens group cam groove C2. The follower pin 18f fitted in the cam groove C1 is aligned on a straight line parallel to the optical axis.1It moves in the optical axis direction while being lined up.
Here, when an external force is applied to the inner lens frame ring 17 inward in the radial direction, the external force is transmitted to the cam ring 15 via the follower pin 17f and is engaged with the lens group cam groove C1. It is received by the follower pin 18f of the one lens unit L1. That is, via the cam follower pin 18f1The group moving frame 18 supports the cam ring 15, and the external force applied to the inner lens frame 17 is applied to the cam ring 15 from opposite directions by the follower pin 17f and the follower pin 18f without being applied to the cam ring 15 from one direction. Since the force is replaced by the pinching force, the cam ring 15 is not deformed and the follower pin 17f does not come off, thereby improving the impact resistance of the cam ring.
[0067]
Further, since the inner lens frame ring 17 and the first group moving frame 18 are always urged in the direction in which the inner lens frame ring 17 and the first group moving frame 18 are separated from each other, the follower pin 17f and the follower pin 18f are always fixed to the lens frame ring cam groove C2 and the lens group. Backlash does not occur when the inner lens frame ring 17 and the first group moving frame 18 move in the optical axis direction and stop due to the rotation of the cam ring 15 due to contact with the side surface of the cam groove C1.
[0068]
Further, the developed shapes of the lens group cam groove C1 and the lens frame ring cam groove C2 areSimilarSince both are provided on the cam ring 15 with their positions slightly shifted in the optical axis direction, the follower pin 18f and the follower pin 17f are always kept close to each other. Therefore, a spring having a short overall length and a small urging force can be used as the compression spring 30, so that the follower pin 18f and the follower pin 17f come into contact with the side surfaces of the lens group cam groove C1 and the lens frame ring cam groove C2 with a strong force. Therefore, the movement of the first group moving frame 18 and the inner lens frame ring 17 does not become smooth.
Further, since a spring having a short overall length can be used, it is possible to change the design of the spring force by changing the wire diameter of the spring.
[0069]
In the present embodiment, since the compression spring 30 is provided between the center projection 17g and the spring accommodating recess 18g, the effect that the zoom lens barrel can be contracted to the shortest state is obtained. Even if a tension spring (not shown) is provided, the effect of backlash between the inner lens frame ring 17 and the first lens unit L1 can be obtained.
[0070]
The rectilinear guide mechanism of the first group moving frame 18, the second group moving frame 19, and the inner lens frame ring 17 of the illustrated embodiment is an example, and the present invention uses the lens group cam groove C1 and the lens frame ring cam groove C2. It does not matter whether the lens group to be guided or the linear guide mechanism of the inner lens frame ring 17 is used. Further, the cam groove C1 for the lens group and the cam groove C2 for the lens frame ring are formed three in the circumferential direction in the illustrated example, but theoretically one or more are sufficient.
[0071]
In addition, the outer lens frame ring 16 and the inner lens frame ring 17 need not be made of synthetic resin and metal, but may be made of only synthetic resin or metal only.
[0072]
Further, in the illustrated embodiment, the zoom lens barrel is described as the best mode, but the present invention may be applied to a single focus collapsible lens barrel including a plurality of lens groups.
[0073]
【The invention's effect】
According to the present invention, even when an external force is applied to the lens frame ring forming the outer peripheral surface of the lens barrel, the cam ring is deformed by the external force.Never.
[Brief description of the drawings]
FIG. 1 is an overall exploded perspective view showing an embodiment of a zoom lens barrel according to the present invention.
FIG. 2FIG. 2 is an enlarged perspective view of a portion shown in an upper part of FIG. 1 of the zoom lens barrel.
FIG. 3FIG. 2 is an enlarged perspective view of a portion shown in a middle part of FIG. 1 of the zoom lens barrel.
FIG. 4FIG. 2 is an enlarged perspective view of a portion shown in a lower part of FIG. 1 of the zoom lens barrel.
FIG. 5 is a longitudinal sectional view of the zoom lens barrel of the present invention in a housed state.
FIG. 6 is a longitudinal sectional view of the zoom lens barrel of the present invention in a housed state at a sectional position different from that in FIG. 5;
FIG. 7 is a longitudinal sectional view showing an upper half of a zoom lens barrel according to the present invention in a housed state and a lower half in a photographing state.
FIG. 8 is a development view of a cam ring.
FIG. 9 is a developed view showing a shape of a lens group cam groove of the cam ring.
FIG. 10 is a developed view showing the relationship between the lens group cam groove of the cam ring and the first group moving frame follower pin and the second group moving frame follower pin.
FIG. 11 is a development view of a cam ring regulating cam groove of a fixed ring and a rotation transmission groove of a rotating ring in which a follower pin of the cam ring is fitted.
FIG.FIG. 7 is a front view of the lens barrel with the barrier mounting plate removed, in a barrier closed state.
FIG. 13SameBarrier openFront viewIt is.
FIG. 14SameWith barrier of barrier blockInner mirror frame ringShow the relationshipFront viewIt is.
FIG. 15 is a graph showing optical axis positions in a zoom section and a storage section of a first lens group (first group moving frame) and a second lens group (second group moving frame).
FIG. 16 is a developed view showing a positional relationship between a cam ring and a barrier opening / closing ring.
FIG. 17 is an enlarged perspective view of a barrier plate.
[Explanation of symbols]
L1 First lens group
L2 Second lens group
L3 Third lens group
10 Substrate
10a solid-state image sensor
11 Housing
11b Outer cylindrical part
11c Filter holder
11d low pass filter
12 Shaft holding
13 Fixed ring
13a Fixed flange
13b Cam ring regulating cam groove
13b1 Straight groove
13b2 Shooting state transition groove
13b3 Zoom section groove
13b4 Assembly groove
13c Straight guide groove
14 Rotating ring
14a Rotation transmission groove
14a1 Straight groove
14a2 Inclined groove
14a3 Circumferential groove
14b gear
14c Spring hook projection
14d through hole
15 Cam ring
15a Thick part
15b Follower pin
15c annular groove
15d rotation transmission surface
15k cutout
16 Outer mirror frame ring
16r mirror frame ring body
16a thick part
16b Straight guide key
16c Straight guide groove
16d bayonet claw
16f relief groove
16x reinforced ring
17 Inner mirror frame ring
17r mirror frame ring body
17a Thick part
17b Straight guide key
17c Inner flange
17d Straight guide boss
17f Follower pin
17g Spring center protrusion
17h Spring hook projection
17j Follower constellation
17k notch
17j Follower constellation
17x Reinforced ring
18 Group Movement Frame
18a Straight guide hole
18b Inner flange
18c Straight guide groove
18d female thread
18f Follower pin for 1 group
18g Spring storage recess
18h rotation permissible part
18j opening
19 2nd group movement frame
19a Straight ahead key
19b annular recess
19c Shade ring
19f Follower pin for 2nd group
20 1 group fixed frame
21 Shutter block
21a Shutter blade
21b FPC board
22 3rd group frame
22a Straight guide rod
23 spring
24 Lead screw
26 slip sheet
28 Information board
29 Elastic ring (rubber band)
30 compression spring
31 Barrier ring
31a Driven surface
31b Spring hook projection
31c Open / close projection
31k cutout
32 Energizing ring
32a Spring hook projection
32b contact end face
32c protrusion
33 Tension spring
40 barrier block
41 Barrier support frame
41a shooting aperture
41b Rotation center boss
42 barrier plate
43 Barrier closed spring
44 Barrier mounting plate
45 Tension spring
Cam groove for C1 lens group
C1Z1 1 group zoom section
C1Z2 2nd group zoom section
C1A1 1st group storage space
Storage space for C1A2 2nd group
Z1T 1st group tele position
Z1W 1 group wide position
Tele position for Z2T 2nd group
Z2W 2nd group wide position
C2 Cam groove for mirror frame ring
C2Z1 1 group zoom section
C2Z2 zoom section for 2nd group
C2B barrier opening / closing section

Claims (2)

A cam ring supported so as to move in the optical axis direction as it rotates; a movable lens group frame supported on the inner peripheral side of the cam ring so as to restrict rotation and allow linear movement in the optical axis direction;
A lens group cam groove formed on the inner peripheral surface of the cam ring; and a follower pin provided on the moving lens group frame which fits into the lens group cam groove. Lens group cam mechanism for moving the frame in the optical axis direction;
A lens frame ring supported on the outer peripheral side of the cam ring so as to be able to regulate rotation and move in a straight line in the optical axis direction; A follower pin provided on the lens frame ring which fits into the cam groove, and a lens frame ring cam mechanism for moving the lens frame ring in the optical axis direction by rotation of the cam ring;
With
The lens group cam groove and the lens frame ring cam groove have substantially the same shape with different positions in the optical axis direction in a region where the movable lens group frame advances and retreats in the optical axis direction.
The follower pin of the movable lens group frame and the follower pin of the lens frame ring are located on substantially the same axis in a direction parallel to the optical axis. 2. The lens barrel according to claim 1, further comprising: spring means for urging the movable lens group frame and the lens barrel ring in a direction approaching or away from each other in an optical axis direction.

Images