JP5375172B2 - Drip-proof structure of lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drip proof structure of a lens barrel, capable of having a moderate operational feeling when an annular member is rotated, exhibiting a drip proof effect, and facilitating manufacture. <P>SOLUTION: A lens barrel includes a plurality of annular members coaxial with each other and relatively rotatable. In the vicinity of the end in the optical axis direction of relatively rotating inner and outer annular members, a sealing member for stopping up an annular gap between the annular members is provided, and the inner annular member is provided with a drain groove formed along the sealing member outside the sealing member in the axial direction. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a drip-proof structure between annular members of a lens barrel.

The lens barrel generally includes a plurality of annular members that are concentric with each other and can be relatively moved along the optical axis or relatively rotated around the optical axis. When one of these annular members is used as a zoom operation ring or a manual focus ring, and the other annular member is advanced or retracted along the optical axis by manually rotating the zoom operation ring or the manual focus ring (adjacent to the radial direction) Conventionally, a photographer can feel an appropriate resistance when manually operating a zoom operation ring or a manual focus ring by intentionally generating a frictional resistance between the annular members. .
As an example of means for producing such a feeling of resistance, the other surface of the annular synthetic leather in which fine hairs are planted on one entire surface is fixed to the outer peripheral surface or inner peripheral surface of the annular member, and the synthetic leather One surface (flocked surface) of this is slidably brought into contact with the inner peripheral surface or outer peripheral surface of another adjacent annular member.

  However, when synthetic leather is used in this way, the photographer can feel an appropriate resistance, but water drops, dust, and the like can enter the lens barrel from the gap between adjacent annular members. It becomes difficult to prevent (provide a drip-proof effect).

For example, Patent Documents 1 and 2 disclose lens barrels that enable the photographer to feel resistance when manually operating the zoom operation ring or the manual focus ring while exhibiting a drip-proof effect.
In the lens barrel of Patent Document 1, the rear end portion of the outer peripheral surface of the front exterior ring and the position immediately after the front exterior ring are rotatable relative to the front exterior ring around the optical axis (relative movement in the optical axis direction). An annular washer made of plastic sheet or vinyl chloride sheet is inserted between the front end of the inner surface of the manual ring, and the manual ring is positioned at the rear end of the manual ring and immediately after the manual ring. An annular washer made of a plastic sheet or a vinyl chloride sheet is inserted between the front end of the inner peripheral surface of the rear exterior ring. Further, a water-repellent material is filled between the rear end portion of the outer peripheral surface of the front outer ring and the front end portion of the inner peripheral surface of the manual ring, and the rear end portion of the outer peripheral surface of the manual ring. The water repellent material is filled in a manner located immediately before the washer between the front end portion of the inner peripheral surface of the rear exterior ring.

  In the lens barrel of Patent Document 1 having such a structure, the washer and the front and rear water-repellent materials exhibit a drip-proof effect, so that water droplets and dust outside the lens barrel are prevented from entering the lens barrel. The In addition, since the washer is sandwiched between the front exterior ring and the manual ring and the washer is sandwiched between the manual ring and the rear exterior ring, the photographer resists when the photographer rotates the manual ring. You can feel the feeling.

  In the lens barrel described in Patent Document 2, a concentric groove is provided on the end surface in the optical axis direction of the focus operation ring, and the groove is filled with viscous grease (water repellent material or oil). A concentric convex ring portion that is loosely inserted into a groove portion provided in the focus operation ring is provided on the end surface of the ring facing the focus operation ring in the optical axis direction.

  In Patent Document 2, with this structure, the exterior ring and the focus operation ring are blocked by grease to prevent entry of water droplets and dust from the outside, and the type of grease is selected by viscosity By doing so, it is also possible to change the operating torque (resistance feeling) of the focus operation ring.

JP 2000-227534 A JP 2003-202481 A

  However, the lens barrel of Patent Document 1 uses a relatively hard material such as a plastic sheet or a vinyl chloride sheet to form an annular washer. Difficult to put out. In particular, when the annular member rotates around the optical axis while sliding in the optical axis direction, synthetic leather is used compared to when the annular member only slides around the optical axis direction or only around the optical axis. It is even more difficult to feel resistance like time. Furthermore, since the washer is formed of a plastic sheet or a vinyl chloride sheet, if there are minute irregularities on the surface of the washer, the rotation of the manual ring may become unsmooth due to the influence of the irregularities. As described above, the washer needs to be accurately molded according to the design shape, but it is not easy to accurately form the washer using a plastic sheet or a vinyl chloride sheet.

  Since the lens barrel of Patent Document 2 is drip-proof by the outer ring and the convex ring formed on the end face in the optical axis direction of the focus operation ring and the grease filled in the groove, the diameter of the outer ring and the focus operation ring It was not applicable if they were not identical.

  Furthermore, since Patent Document 2 has a structure in which the resistance (operating torque) changes and the drip-proof effect changes depending on the strength of the pressure sandwiching the light shielding member between the two lens barrels, if the pressure is weakened to reduce the resistance, it is prevented. On the other hand, if the drip effect is too small, and if the drip-proof effect is increased by increasing the pressure, the resistance becomes too high, and there is a problem that it is difficult to adjust the drip-proof performance and resistance.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a drip-proof structure for a lens barrel that can feel an appropriate operational feeling when a circular member is rotated and can exhibit a drip-proof effect and is easy to manufacture.

In the lens barrel having a plurality of annular members that can rotate relative to each other while being coaxial with each other, the present invention that solves the above-described problems is provided with either the inner or outer annular member on either the inner or outer annular member that rotates relatively. by positioning in the vicinity of an end of the axial member, the provision securing the annular busy technique other gaps of the annular member and the sliding sealing member between the inner outside of the annular member, the inner annular member an outer peripheral surface, the sealing member providing the one or more drain grooves intends along the, and the gutter, the axial direction from the axial position of the sealing member without axial position overlap with the sealing member It is located on the end side.

  When the drainage grooves are provided at a plurality of locations, a difference may be provided in the depth of one or all of the drainage grooves. Preferably, it is deeper toward the subject side and shallower toward the camera body side. Since the front end of the lens barrel is more likely to be covered with water droplets or the like, or water droplets or the like are more likely to enter, an effective drip-proof performance can be obtained.

  It is practical that the drainage groove is formed between a plurality of bank portions protruding on the outer peripheral surface of the inner annular member. By forming a plurality of bank portions, it becomes difficult for water droplets to reach the sealing member through the inner annular member, and the drip-proof effect is improved.

It is preferable that the outer annular member is provided with a flange portion that extends to the upper side of the drainage groove. By providing the collar portion, it is difficult for water droplets to enter the drainage groove, it is difficult to reach the reeling member beyond the drainage groove, and the drip-proof effect is enhanced.
The collar portion may have a slight gap in the direction opposite to the sealing member as long as it can substantially cover the drainage groove, but it is preferable to completely cover the collar portion.
Furthermore, it is preferable that the flange portion is formed by inclining the surface facing the drainage groove in the direction in which the gap or gap between the drainage groove and the bottom of the drainage groove extends. Water droplets that have entered the drainage channel can easily come out of the drainage channel from the inclined portion, and the drainage capacity is increased.

  The depth of the drainage groove is preferably formed so that the upper part is deeper and the lower part is shallower at the normal position of the lens barrel. With this configuration, water droplets that have entered the drainage groove from the upper part of the lens barrel flow down along the drainage groove, and can easily drop out of the lens barrel from a shallow portion, thereby increasing the drainage capacity.

  In the present invention, since the water droplets dropped on the lens barrel first enter the drainage groove, the water droplets are unlikely to reach the sealing member through the inner annular member, and have a high drip-proof effect. In addition, the present invention is less dependent on the drip-proof effect of the sealing member, so that the resistance feeling by the sealing member can be easily set as desired.

1 is a cross-sectional view of an embodiment of a zoom lens barrel to which the present invention is applied, cut vertically along a plane passing through an optical axis. It is sectional drawing which showed the upper half from the optical axis by carrying out a longitudinal cut in the surface which passes along an optical axis in the state which adjusted the focus to the short distance of the zoom lens barrel. FIG. 4 is a cross-sectional view showing the upper half and the lower half of the zoom lens barrel in the tele end and wide end zoom states of the zoom lens barrel vertically cut by a plane passing through the optical axis. It is sectional drawing which expands and shows the drip-proof structure of the zoom lens barrel. It is sectional drawing which expands the upper half from an optical axis and shows the drip-proof structure of the zoom lens barrel. It is sectional drawing which expands the upper half from an optical axis and shows the drip-proof structure of the zoom lens barrel. FIG. 7 is a transverse cross-sectional view illustrating the shape of a drain groove of the zoom lens barrel crossing along the cutting line VII-VII in FIG. 1. In the drip-proof structure of the same zoom lens barrel, it is a diagram showing an embodiment in which the depth of the drainage groove is different between the lens front end portion and the mount portion side, (A) is the lens front end side, (B) (C) is sectional drawing which expands and shows the drip-proof structure by the side of a mount. In the drip-proof structure of the zoom lens barrel, FIG.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of an embodiment of a zoom lens barrel to which the present invention is applied, taken longitudinally along a plane passing through the optical axis.

  The lens barrel 10 is an interchangeable lens zoom lens barrel including two lens groups L1 and L2. At the rear end portion of the first fixed ring 11 that is a cylindrical body centered on the optical axis O of each lens group L1, L2, a mount portion 12 that is detachable from the mount portion of the camera body (not shown) is provided. ing. Further, a second fixed ring 13 which is a cylindrical body concentric with the first fixed ring 11 is disposed on the inner peripheral side of the first fixed ring 11, and the rear end portion of the second fixed ring 13 is A fixed ring 11 is fixed to the front surface of the rear wall.

The front end portion of the first fixing ring 11, the zoom operation ring 15 is a cylindrical member forming a first fixing ring 11 and the second fixing ring 13 concentrically, 17 can rotate around the optical axis O (optical axis O direction Is not possible). The zoom operation ring 15 includes a zoom operation ring 17 connected to the front end so as to rotate integrally. In other words, the zoom operation rings 15 and 17 are divided into front and rear, and the zoom operation ring 17 is connected to the front portion of the zoom operation ring 15 so as to rotate as a unit. A grip ring 16 is fixed to the outer peripheral surfaces of these zoom operation rings 15 and 17.

  On the outer peripheral surface of the front end portion of the first fixed ring 11, the rear end portion of the focus ring 19, which is a cylindrical body concentric with the first fixed ring 11, is in a state where movement in the optical axis O direction is restricted. It is provided so as to be rotatable around the axis O. The rear end of the focus ring 19 is located on the inner peripheral side of the zoom operation rings 15 and 17. Although not shown, a gear is formed at the rear end of the inner peripheral surface of the focus ring 19, and this gear is rotatably supported near the front end of the outer peripheral surface of the second fixed ring 13. Are engaged. When the lens barrel 10 is mounted on the camera body, the output gear is connected to a focusing motor built in the camera body via a gear mechanism built in the camera body.

  A cam ring 21 that is a cylindrical body concentric with the second fixed ring 13 is disposed on the outer peripheral side of the second fixed ring 13. The cam ring 21 is supported so as to freely rotate around the optical axis O without moving the optical axis O with respect to the second fixed ring 13, and is further connected to the zoom operation ring 15 via the zoom interlocking lever 18. Has been. Therefore, when the zoom operation ring 15 rotates, the cam ring 21 rotates around the optical axis O without moving in the optical axis O direction.

  The second fixed ring 13 supports a second group support frame 23 located on the inner peripheral side of the cam ring 21. The second group support frame 23 is a member that supports the second lens group L2 that is a variator lens group, and is linearly guided by a straight guide groove formed in the second fixed ring 13, and is formed on the inner peripheral surface of the cam ring 21. The cam is connected to the cam groove. Accordingly, when the cam ring 21 rotates through the zoom operation ring 15, the second group support frame 23 does not rotate around the optical axis O, but at a speed according to the cam groove lead of the cam ring 21. Move forward and backward along.

  A rectilinear ring 25, which is a cylindrical body concentric with the cam ring 21, is fitted to the outer peripheral surface of the distal end portion of the cam ring 21. Although not described in detail, the rectilinear ring 25 is supported so as to advance and retract along the optical axis O without rotating to the second fixed ring 13 and rotates when the cam ring 21 is rotated by the cam mechanism between the cam ring 21 and the cam ring 21. Instead, they are connected so as to advance and retract along the optical axis O.

Between the rectilinear ring 25 and the focus ring 19, a rotation feeding ring 27 which is a cylindrical body concentric with these is disposed. Although not described in detail, the rotary payout ring 27 is connected to the rectilinear ring 25 by a cam mechanism , and can move forward and backward in the direction of the optical axis O with respect to the focus ring 19 and rotate integrally around the optical axis O. It is connected. Therefore, when the cam ring 21 rotates, the rotation feeding ring 27 moves forward and backward without rotating together with the rectilinear ring 25 that moves forward and backward along the optical axis O by the cam mechanism between the cam ring 21 and the cam ring 21. On the other hand, when the focus ring 19 rotates, the rotation extension ring 27 moves forward and backward along the optical axis O by a cam mechanism between the rotation ring 25 and the rectilinear ring 25 while rotating integrally with the focus ring 19.

  In the front end portion of the second fixed ring 13, the rear end portion of the first group support frame 29, which is a cylindrical body that supports the first lens group L1, is connected so as to be linearly movable in the direction of the optical axis O without rotating. Yes. The first lens unit L1 functions as a compensator lens and a focusing lens. The outer periphery of the front end portion of the first group support frame 29 is connected so as to be relatively rotatable with respect to the rotation feeding ring 27 and to move together in the optical axis O direction. Accordingly, when the focus ring 19 is rotated, the rotation feeding ring 27 moves forward and backward, and the first group support frame 29 supports the first lens group L1 by this forward and backward movement, so that the optical axis O does not rotate. Move forward and backward along. On the other hand, when the zoom operation ring 15 is rotated, the first group support frame 29 is lighted with respect to the second fixed barrel 13 and the focus ring 19 by the rectilinear ring 25 and the rotation extension ring 27 in a state where the rotation is restricted. Move back and forth in the direction of axis O. FIG. 2 shows a state in which the focus ring 19 is rotated so that the rotation feeding ring 27, the first group support frame 29, and the first lens group L1 are moved forward most.

  Here, when the cam ring 21 rotates and the rectilinear ring 25 advances, the rotation feeding ring 27 advances and retreats without rotating, and when the focus ring 19 rotates, the rotation feeding ring 27 advances and retreats while rotating. It is formed as follows.

When the cam ring 21 rotates, the second group support frame 23 holds the second lens group L2 by the cam mechanism lead between the cam ring 21 and the second group support frame 23. The first group support frame 29 holds the first lens group L1 without rotating along the straight guide groove, and the cam mechanism between the straight ring 25 and the cam ring 21 holds the first lens group L1. It moves forward and backward without rotating and is zoomed (Fig. 3) .

  Next, a drip-proof structure provided between the rotation feeding ring 27 and the first group support frame 29, between the front zoom operation ring 17 and the focus ring 19, and between the rear zoom operation ring 15 and the first fixed ring 11. Will be further described with reference to FIGS.

  FIG. 4 is an enlarged cross-sectional view showing a drip-proof structure between the rotary feeding ring 27 and the first group support frame 29. A lasha 31 as a sealing member is bonded between the front inner peripheral surface of the rotary feeding ring 27 and the outer peripheral surface of the first group support frame 29. The lashers 31 are formed in an annular shape, are adhered to the outer peripheral surface of the first group support frame 29, and are in slidable contact with the rotary feeding ring 27, but the reverse is also possible. In addition, the sealing member is not limited to the rasha, such as an annular synthetic leather in which fine hairs are planted on the entire surface.

  On the outer peripheral surface of the first group support frame 29, a drainage groove 29 a regulated by the bank portions 29 b and 29 c is formed on the outer side of the lens barrel from the rasha 31, here at a position slightly separated from the front end surface of the rasha 31. Has been. The bank portions 29 b and 29 c, that is, the drainage grooves 29 a are formed over the entire circumference of the first group support frame 29. The bank portions 29b and 29c are formed higher in the front bank portion 29b.

  At the front end portion of the rotary feeding ring 27, a flange portion 27a that covers the drainage groove 29a is formed. The eaves part 27a extends beyond the outer peripheral surface of the rear bank part 29c to a position where it covers the drainage groove 29a and leaves a slight gap with the front bank part 29b. Further, the flange portion 27a is formed with a tapered portion 27a1 which is inclined on the surface facing the drainage groove 29a in a direction in which a gap or a gap with the bottom of the drainage groove 29a increases toward the tip.

  Since the drainage groove 29a having such a flange portion 27a is provided outside the rasha 31, first, water droplets that have fallen on the lens barrel enter the drainage groove 29a from the gap between the flange portion 27a and the bank portion 29b. Although entering, the water droplets that have entered the drainage groove 29a flow downward in the direction of gravity along the drainage groove 29a, and fall out of the drainage groove 29a through the gap between the lower flange portion 27a and the bank portion 29b. That is, when a water droplet starts falling with the camera held in the normal position, the water droplet travels through the drainage groove 19a and falls outside the lens barrel. Furthermore, in this embodiment, since the lower flange portion 27a is inclined in a direction in which the tapered portion 27a1 is lowered toward the gap with the drainage groove 29a, the drainage capacity is increased.

  FIG. 5 is an enlarged cross-sectional view showing a drip-proof structure between the front zoom ring 17 and the focus ring 19. Between a front end inner peripheral surface of the front zoom ring 17 and an outer peripheral surface of the focus ring 19, a lasha 33 as a sealing member is bonded. The lasher 33 is adhered to the outer peripheral surface of the focus ring 19 and is in slidable contact with the inner peripheral surface of the front zoom ring 17, but the reverse is also possible.

The outer peripheral surface of the focus ring 19 is regulated by the bank portions 19b and 19c on the outer side of the lens barrel of the zoom ring 17 in front of the rasha 33, here at a position slightly separated from the front end surface of the rasha 33. A drainage groove 19a is formed. The bank portions 19b and 19c, that is, the drainage grooves 19a are formed over the entire circumference of the focus ring 19. The bank portions 19b and 19c are formed higher in the front bank portion 19b.
At the front end portion of the front zoom ring 17, a flange portion 17a that covers the drainage groove 19a is formed. The flange portion 17a extends beyond the outer peripheral surface of the rear bank portion 19c to a position where it covers the drainage groove 19a and leaves a slight gap with the upper surface of the front bank portion 19b.

  Since the drainage groove 19a having such a flange portion 17a is provided on the outer side of the rasha 33, the water droplets that have fallen on the lens barrel first enter the drainage groove 19a from the gap between the flange portion 17a and the bank portion 19b. Although entering, the water droplets that have entered the drainage groove 19a flow downward in the direction of gravity along the drainage groove 19a, and flow out of the drainage groove 19a through the gap between the lower flange portion 17a and the bank portion 19b. That is, when a water droplet starts falling with the camera held in the normal position, the water droplet travels through the drainage groove 19a and falls out of the lens barrel from the bottom.

  In addition, between the front end part of the focus ring 19 and the rotation feeding ring 27, drip-proofing is performed by a lasha 37 as a sealing member. The outer surface of the lasher 37 is bonded to the inner peripheral surface of the focus ring 19, and the inner peripheral surface is in slidable contact with the rotary feeding ring 27.

  FIG. 6 is an enlarged cross-sectional view showing a drip-proof structure between the rear zoom operation ring 15 and the first fixed ring 11. Between a rear end inner peripheral surface of the rear zoom operation ring 15 and an outer peripheral surface of the first fixed ring 11, a lasha 35 as a sealing member is bonded. The lasher 35 is bonded to the outer peripheral surface of the first fixed ring 11 and is in slidable contact with the inner peripheral surface of the zoom operation ring 15 at the rear, but the reverse may be possible.

  The outer peripheral surface of the first fixed ring 11 is restricted by the bank portions 11b and 11c on the outer side of the lens barrel of the zoom operation ring 15 at the rear part of the rear part 35, here slightly away from the rear end face of the rear part 35. A drainage groove 11a is formed. The bank portions 11 b and 11 c, that is, the drainage grooves 11 a are formed over the entire circumference of the first fixed ring 11. The bank portions 11b and 11c are formed higher in the front bank portion 11b. The rear bank portion 11 c is formed by the outer peripheral surface of the first fixed ring 11.

  At the rear end portion of the rear zoom operation ring 15, a flange portion 15a that covers the drainage groove 11a is formed. The flange portion 15a extends beyond the outer peripheral surface of the front bank portion 11b to a position where it covers the drainage groove 11a and leaves a slight gap with the rear bank portion 11c. Further, the flange portion 15a is formed with a tapered portion 15a1 whose surface facing the drainage groove 11a is inclined in a direction in which a gap or a gap with the bottom of the drainage groove 11a increases toward the tip.

  Since the drainage groove 11a having such a collar portion 15a is provided outside the lens barrel from the Rasha 35, the water droplets that have fallen on the lens barrel are first drained from the gap between the collar portion 15a and the bank portion 11c. Although entering the groove 11a, the water droplets that have entered the drainage groove 11a flow downward along the drainage groove 11a in the direction of gravity, and then flow down to the outside of the drainage groove 11a through the gap between the lower flange portion 15a and the bank portion 11c. That is, when a water droplet starts falling with the camera held in the normal position, the water droplet travels through the drainage groove 11a and falls out of the lens barrel from the bottom. Here, the drainage groove 11a becomes shallower in the downward direction, and the taper portion 15a1 of the flange portion 15a is inclined in the direction in which the drainage groove 11a falls outside the drainage groove 11a (the gap is widened). It becomes easy to flow out of the drainage groove 11a along, and drainage capacity becomes high.

  Further, the drainage groove 11a is formed so that the upper part is deeper and the lower part is shallower with the lens placed in the normal position (FIG. 7). By changing the depth of the drainage groove 11a in this way, water droplets that have fallen on the lens barrel while being held at the normal position enter the upper drainage groove 11a and from the lower drainage groove 11a to the lens mirror. It becomes easy to fall out of the cylinder.

  As described above, according to the drip-proof structure of the embodiment, the drain grooves 29a, 19a, and 11a are provided at positions outside the lens barrel relative to the rasha 31, 33, and 35 that are sealing members that seal between the relatively rotating lens barrels. The water droplets first enter the drainage grooves 29a, 19a, 11a, flow along the drainage grooves 29a, 19a, 11a, and fall out of the lens barrel from the bottom, so that the drip-proof waterproof effect is higher than with the sealing member alone. .

According to the drip-proof structure provided with the flanges 27a, 17a, and 15a covering the drainage grooves 29a, 19a, and 11a, water droplets are blocked by the flanges 27a, 17a, and 15a, and are difficult to enter the drainage grooves 29a, 19a, and 11a. Since it flows down the lens barrel through the outer surfaces of the collar portions 27a, 17a, 15a, the drip-proof waterproof effect is further enhanced.
The collar part may be either a shape that completely covers the drainage groove (the collar part 17a) or a shape that substantially covers the drainage groove (the collar parts 27a and 15a).
Although the taper portions 27a1 and 15a1 are formed on the flange portions 27a and 15a, it is preferable to provide a similar taper portion on the other flange portion 17a.

  As shown in FIG. 6, according to the drip-proof structure in which the depth of the drainage groove 19a is deeper in the upper part at the upper position and shallower in the lower part, the water droplets entering the drainage groove 19a are gravity along the drainage groove 19a. When flowing downward, since the bottom is shallow in the downstream region, it easily overflows from the drainage groove 19a and drops outside the lens barrel, and the drip-proof waterproof effect is further enhanced.

  In other embodiments, the depth of each drainage groove 129a, 119a, 111a may be different. FIGS. 4A, 4B, and 5C show structures of an example in which the subject side (lens front end side) and the camera body side (mount side) of the lens barrel are different from each other. This is shown in the same longitudinal sectional view as in FIG. In addition, the same code | symbol is attached | subjected to the same member. In this embodiment, the depths of the drain grooves 129a, 119a, and 111a are deeper as the drain grooves on the subject side (the front end side of the lens barrel) and shallower toward the mount side. Since the water droplets easily enter the tip of the lens barrel, the drain groove is formed deeper at the tip of the lens barrel to enhance the drip-proof effect.

  In yet another embodiment, the number of drain grooves is plural. FIG. 9 shows an embodiment in which there are two drain grooves 29a on the front end side of the lens barrel. In this embodiment, a third bank portion 29d is projected between the bank portions 29b and 29c to form two drain grooves 29a1 and 29a2. The drip-proof effect is further enhanced by forming the plurality of drain grooves 29a1 and 29a2. The number of drainage grooves may be three or more.

  The embodiment in which the drip-proof structure of the present invention is applied to the two-group zoom lens barrel has been described above, but the present invention is not limited to this embodiment and can be applied to other lens barrels.

11 first fixed ring 11a drainage groove 11b bank 11c bank 12 mount part 13 second fixed ring 15 zoom operation ring 15a flange 15a1 taper 17 front zoom operation ring 17a flange 19 focus ring 19a drain groove 19b bank Portion 19b bank portion 23 second group support frame 25 rectilinear ring 27 rotation feeding ring 27a flange portion 27a1 taper portion 29 first group support frame 29a drainage groove 29b bank portion 29c bank portion 29d bank portion 31 Rasha (sealing member)
33 Rasha (sealing member)
35 Rasha (sealing member)

Claims (7)

In a lens barrel having a plurality of annular members that can rotate relative to each other while being coaxial with each other,
On one of the inner and outer ring to rotate relative to the inner outside by positioning in the vicinity of an end of the axial direction of the annular member, the inner outside of the fort technique other annular member an annular gap between the annular member A fixed sealing member that is in sliding contact with
The outer peripheral surface of the inner annular member, the provision of the one or more drain grooves intends along the sealing member, and
The drainage groove is located on the axial end side of the sealing member without overlapping the axial position of the sealing member,
A drip-proof structure for lens barrels.   2. The drip-proof structure for a lens barrel according to claim 1, wherein the drain grooves are provided at a plurality of locations, and the depth of one or all of the drain grooves is different.   3. The drip-proof structure for a lens barrel according to claim 1 or 2, wherein the drainage groove is formed between a plurality of bank portions protruding from the outer peripheral surface of the inner annular member. .   4. The drip-proof structure of the lens barrel according to claim 1, wherein the outer annular member includes a flange that extends to the upper side of the drainage groove and covers the drainage groove. Drip-proof structure of the cylinder.   5. The drip-proof structure for a lens barrel according to claim 4, wherein the flange portion has a surface facing the drainage groove inclined in a direction in which a gap or a gap with the bottom of the drainage groove extends toward the tip. Drip-proof structure of lens barrel.   6. The drip-proof structure for a lens barrel according to claim 1, wherein the drainage groove is formed so that the upper portion is deeper and the lower portion is shallower at the normal position of the lens barrel. Drip-proof structure of lens barrel.   7. The drip-proof structure of the lens barrel according to claim 1, wherein the sealing member is fixed to the outer peripheral surface of the inner annular member and is in sliding contact with the inner peripheral surface of the outer annular member. Drip-proof structure of formed lens barrel.

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