JP6051785B2 - Drip-proof structure of lens barrel - Google Patents

Description

  The present invention relates to a drip-proof structure for a lens barrel.

  In lens barrels, inner and outer annular members that are coaxial and relatively move are widely used. In order to prevent raindrops from entering through the annular gap between the inner and outer annular members and to provide appropriate operating resistance (operation feeling), an annular drip-proof strip (strip) is provided on one of the peripheral surfaces of the inner and outer annular members. ) And the other surface of the annular drip-proof band material are brought into contact with the other peripheral surface. Patent Document 1 proposes to use synthetic leather as the annular drip-proof material.

JP 2008-203773 A

  The drip-proof structure of the lens barrel of Patent Document 1 was able to provide drip-proof properties and appropriate operating resistance with a small lens barrel. However, a large-diameter lens barrel is a cosmetic coating (such as a chirimene coating) that can be formed on the surface of the annular member by the difference in roundness between the inner and outer annular members (a change in the circumferential direction of the radial gap) or on the surface of the annular member. Or, when drying, it is difficult to control the size of the gap between the inner and outer annular members that make up the drip-proof structure due to the coating that can be uneven by heat shrinkage, resulting in a large gap variation and suitable drip-proof performance and operation There was a problem that the feeling decreased. Even in the case of a small lens barrel, there is a similar problem in the case where the accuracy of the gap between the inner and outer annular members constituting the drip-proof structure is low, or when coating with unevenness is applied.

  In the present invention, on the basis of the above problem awareness, the radial gap and roundness difference (circumferential change in the radial gap) between the inner and outer annular members are relatively large, or there are relatively large irregularities on the surface. Even in such a case, an object is to obtain a drip-proof structure of a lens barrel that can provide suitable drip-proof properties and operational feeling.

The present invention focuses on providing an elastic deformation layer having a lower repulsion property than the drip-proof layer on the drip-proof layer so as to increase flexibility in moving the annular drip-proof band in the radial direction. It was made based on.

  That is, the drip-proof structure of the lens barrel of the present invention includes an inner and outer annular members that are coaxial and can be moved relative to each other. In the drip-proof structure of the lens barrel in which one surface is bonded and the other peripheral surface is in contact with the other surface inside and outside the annular drip-proof material, the annular drip-proof material includes a drip-proof layer, It has a laminated structure with an elastically deformable layer having a lower rebound than the drip-proof layer, the elastically deformable layer is bonded to one of the peripheral surfaces of the inner and outer annular members, and the drip-proof layer is a peripheral surface of the inner and outer annular members It touches the other of these.

  An annular groove for housing the annular drip-proof band material is formed in the annular member on the side to which the annular drip-proof band material is bonded, and the drip-proof layer protrudes radially outward from the annular groove, and other than the drip-proof layer The layer is preferably located in the annular groove.

  Specifically, the elastic deformation layer is preferably composed of any one of polyethylene resin, polyurethane resin, and poron resin.

  The drip-proof layer is preferably subjected to a raising treatment in advance on the contact surface with the annular member.

  The annular drip-proof band material may further include a thin expansion / contraction suppression layer that is positioned closer to the elastic deformation layer than the drip-proof layer and has a lower elasticity and a thinner wall than the elastic deformation layer.

  When the expansion / contraction suppression layer is arranged, it can be composed of any of PET resin, PC, polypropylene, a resin sheet material, and a resin film material, and PC and polypropylene are particularly preferable.

  The present invention relates to a drip-proof structure of a lens barrel in which an annular drip-proof band material is interposed in a gap between inner and outer annular members that are coaxial and relatively movable, and the drip-proof band material, the drip-proof layer, and the drip-proof layer. It has a laminated structure with an elastic deformation layer that is less repulsive than the droplet layer, the elastic deformation layer is bonded to one of the peripheral surfaces of the inner and outer annular members, and the drip-proof layer is in contact with the other peripheral surface of the inner and outer annular members As a result, due to the elastic deformation of the elastic deformation layer in the radial direction, the difference in the radial gap and roundness of the inner and outer annular members (change in the circumferential direction of the radial gap) is relatively large, or the surface is relatively Even when there are large irregularities, suitable drip-proof property and operational feeling can be obtained.

It is a vertical side view of the upper half part which shows one Embodiment of the lens-barrel to which the drip-proof structure of this invention is applied. It is the II section expanded sectional view of FIG. It is a perspective view of the cyclic | annular state of the cyclic | annular drip-proof band material simple substance of FIG. It is sectional drawing corresponding to FIG. 2 which shows other embodiment of the drip-proof structure of this invention. It is sectional drawing of the cyclic | annular drip-proof band material single-piece | unit which shows other embodiment of this invention. It is the elements on larger scale of the modification of an annular drip-proof belt material. It is the elements on larger scale similar to FIG. 6 of another modification of an annular drip-proof band material. It is the elements on larger scale similar to FIG. 6 of another modification of an annular drip-proof band material. It is the elements on larger scale similar to FIG. 6 of another modification of an annular drip-proof band material. It is the elements on larger scale similar to FIG. 6 of another modification of an annular drip-proof band material.

  FIG. 1 shows a lens barrel 10 to which the drip-proof structure of the present invention is applied. The lens barrel 10 includes a coaxial inner annular member 11 and an outer annular member 12 centering on the optical axis O. The inner annular member 11 is a member that fixes the first lens unit L1 and moves linearly in the optical axis direction, and the outer annular member 12 is a rotating member that can rotate the outer periphery of the inner annular member 11 (for example, a focus ring). It is. As apparent from FIG. 2, the coating on the outer peripheral surface of the inner annular member 11 is damaged if they are in contact between the outer peripheral surface of the inner annular member 11 and the inner peripheral surface of the outer annular member 12. Therefore, an annular space (gap) 13 is present. The drip-proof structure of the present embodiment is provided between the outer peripheral surface of the inner annular member 11 and the inner peripheral surface of the outer annular member 12. The present embodiment is intended for a large (large diameter) lens barrel having an outer diameter of the inner annular member 11 of about 65 mm (a gap between the annular spaces 13 is 0.15 to 0.3 mm). The present invention can also be applied to a smaller (small diameter) lens barrel.

  On the inner peripheral surface of the outer annular member 12, an annular groove (inwardly open annular groove) 14 located in the plane orthogonal to the optical axis is formed, and in this annular groove 14, an annular drip-proof band material (strip). 20 is located. The annular drip-proof band member 20 is formed on the drip-proof layer 21 made of a light-transmitting synthetic leather that contacts the outer circumferential surface of the inner annular member 11 and the bottom surface of the annular groove 14 (the inner circumferential surface of the outer annular member 12). It has an elastically deformable layer (film) 22 to be bonded. The drip-proof layer 21 and the elastic deformation layer 22 are also bonded by an adhesive layer (not shown), and the elastic deformation layer 22 is bonded to the bottom surface of the annular groove 14 by the adhesive layer 23. The elastic deformation layer 22 is formed of a material having a lower resilience than the drip-proof layer 21, that is, a material having a restoring force weaker than that of the drip-proof layer 21 when a compression force is applied. ), The drip-proof layer 21 is brought into contact (elastic contact) with the outer peripheral surface of the inner annular member 11 in accordance with the size of the gap of the annular space 13 or the variation in the circumferential direction.

  Specifically, the drip-proof layer 21 is made of cloth-like synthetic leather (woven fabric, knitted fabric, nonwoven fabric impregnated with a resin material), and the inner peripheral surface thereof is subjected to raising treatment ( The inner peripheral surface constitutes a raised surface 21a). Synthetic leather subjected to raising treatment is well known, and the entire thickness including the raising portion is thicker than the gap of the annular space 13. The drip-proof layer 21 is dipped in a water repellent (water repellent) and subjected to a water repellent treatment. The drip-proof layer 21 can be formed of a raised cloth, a flocked cloth or the like instead of the synthetic leather.

The elastic deformation layer 22 is made of polyethylene resin. The thickness of the elastic deformation layer 22 is important for bringing the drip-proof layer 21 into contact (elastic contact) with the outer peripheral surface of the inner annular member 11 in accordance with the size of the gap in the annular space 13 or the variation in the circumferential direction. is there. The thickness of the elastic deformation layer 22 may be a thickness that can obtain a necessary elastic deformation amount. When the elastic deformation layer 22 is made of polyethylene resin, it is difficult to obtain a necessary elastic deformation amount when the thickness is less than 0.3 mm.
The thickness of the drip-proof layer 21 is set according to the gap of the annular space 13, and the thickness of the elastic deformation layer 22 and the entire thickness of the annular drip-proof band material 20 are the depth of the annular space 13 and the depth of the annular groove 14. It is set according to.

  The drip-proof layer 21 and the elastic deformation layer 22 are bonded to each other with an adhesive to form a cloth, and are cut into a strip shape having the same length as the circumferential length of the bottom surface of the annular groove 14. And the both ends 33 and 37 of the cut-out annular drip-proof material 20 are made to oppose as shown in FIG. FIG. 3 shows a single shape of the annular drip-proof band member 20 made into a ring.

  The structure (shape) of the butted end portion 33 and the butted end portion 37 of the annular drip-proof material 20 is proposed in Patent Document 1. That is, both the circumferential butting ends 33 and 37 of the annular drip-proof material 20 are linearly extending in the optical axis direction (first end portions) 34 and 38 linearly extending rearward from the front surface of the annular drip-proof material 20. And optical axis direction linear portions (second end portions) 35 and 39 extending linearly forward from the rear surface of the annular drip-proof material 20 (the front end positions thereof are the optical axis direction linear portion 34 and the optical axis direction linear portion 38). The same as the rear end position), the rear end of the optical axis direction linear portion 34 and the front end of the optical axis direction linear portion 35, and the rear end of the optical axis direction linear portion 38 and the front end of the optical axis direction linear portion 39, respectively. Circumferential linear portions (connecting portions) 36 and 40 extending linearly in the circumferential direction are provided. Thus, the optical axis direction linear part 34 (optical axis direction linear part 38) and the optical axis direction linear part 35 (optical axis direction linear part 39) are different from each other in the circumferential direction position. 40), the butt end portions 33 and 37 have a larger cutting area than the case where the butt end portions 33 and 37 are simply cut surfaces perpendicular to the longitudinal direction of the annular drip-proof band member 20. (The cutting distance is long).

  In the state where the annular drip-proof band 20 is bonded and fixed to the bottom of the annular groove 14, the drip-proof layer 21 protrudes from the annular groove 14 and faces the annular space 13, and the elastic deformation layer 22 is in the annular groove 14. Is located. The drip-proof layer 21 overlaps the boundary between the annular groove 14 and the annular space 13 when viewed from the optical axis direction. In this way, when the drip-proof layer 21 straddles the boundary between the annular groove 14 and the annular space 13, good drip-proof performance can be obtained.

  A clearance space 14 a exists between the rear end face of the annular drip-proof material 20 and the annular groove 14. The annular drip-proof band material 20 may have a width equal to the groove width of the annular groove 14 (length in the optical axis direction), but when the width becomes wider than the groove width of the annular groove 14 due to a manufacturing error or the like, It will be pushed into the annular groove 14 while being compressed in the direction of the optical axis, which may cause problems such as deformation and distorted irregularities that impair drip-proof properties and operational feeling. Therefore, in the embodiment of FIG. 2, the groove width of the annular groove 14 is formed wider than the width of the annular drip-proof material 20, and the escape space 14a is present to prevent the above problem. The escape space 14a may exist on the annular space 13 side.

According to the above drip-proof structure, even if there is a slight variation in the circumferential gap of the annular space 13, the raised surface 21 a of the drip-proof layer 21 is elastically applied to the outer peripheral surface of the inner annular member 11 by the elastic deformation layer 22. Pressed against. Since the drip-proof layer 21 faces the annular space 13 and is water-repellent, even if the outer annular member 12 is moved relative to the inner annular member 11 by the focusing operation (rotation and axial movement), the annular space The raindrop does not enter through the inner ring member 11 and the outer ring member 12 through the inner ring member 13, and appropriate rotation resistance is given to the outer ring member 12. Moreover, since the elastic deformation layer 22 is located in the annular groove 14, there is little possibility of being affected by raindrops. Further, since the entire water-repellent material 20 is impregnated with the water repellent, the water repellent prevents the water droplets and dust from entering the lens barrel 10 from the annular space 13. Has been. Moreover, since the drip-proof layer 21 is opaque, it is possible to prevent stray light from entering.
In this drip-proof structure, since the annular groove 14 is formed in the outer annular member 12, water droplets and the like attached to the inner annular member 11 are transmitted to the lower side of the inner annular member 11 by its own weight (gravity). The lower annular groove 14 has an upside-down relationship with the upper annular groove 14, and the bottom is positioned below the gravitational direction (on the ground side) and the upper gravitational direction is open. Therefore, according to this drip-proof structure, even if water drops transmitted to the lower side of the inner annular member 11 exceed the drip-proof layer 21, they flow into the lower annular groove 14 (relief space 14a) on the lower side of the outer annular member 12. Are retained (water storage) and are not transmitted to the inside of the lens barrel, so the drip-proof effect is enhanced.

  FIG. 4 shows an annular drip-proof band material in which an annular groove (outwardly open annular groove) 15 is formed on the outer peripheral surface of the inner annular member 11, and the inside and outside of the annular groove 15 are opposite to the embodiment of FIG. An embodiment in which 20 is bonded and fixed is shown. That is, in this embodiment, the drip-proof layer 21 is positioned on the outer peripheral side and the elastic deformation layer 22 is positioned on the inner peripheral side, and the drip-proof layer 21 contacts the inner peripheral surface of the outer annular member 12. In this embodiment, an escape space 15 a exists between the rear end surface of the annular drip-proof band member 20 and the annular groove 15, and the drip-proof layer 21 is a boundary between the annular groove 15 and the annular space 13 when viewed from the optical axis direction. And overlap. According to this embodiment, since the annular groove 15 is formed in the inner annular member 11, the elastic deformation layer 22 is difficult to come out of the annular space 13.

  FIG. 5 shows another embodiment of the annular drip-proof band member 20A used in the drip-proof structure of the lens barrel of the present invention. This embodiment includes a thin expansion / contraction suppression layer (film) 24 that is lower in elasticity (difficult to stretch) than the elastic deformation layer 22 between the drip-proof layer 21 and the elastic deformation layer 22 of the annular drip-proof band material 20A. This is an embodiment. The expansion / contraction suppression layer 24 may be included between the elastic deformation layer 22 and the adhesive layer 23. Alternatively, the adhesive layer 23 may be formed of an adhesive having lower stretchability (difficult to stretch) than the elastic deformation layer 22. The expansion / contraction suppression layer 24 can be composed of any of PET resin, PC, polypropylene, resin sheet material, and resin film material, and PC and polypropylene are particularly preferable. The thickness can be made thinner as the stretchability of the material of the stretch suppressing layer 24 is lower. When this expansion / contraction suppression layer 24 is added, the expansion / contraction of the entire annular drip-proof band material 20A is suppressed, so that it becomes easy to put the cyclic drip-proof band material 20A into the annular groove 14 or the annular groove 15 to form an annular shape, Moreover, there is little possibility that the butt end portion is separated due to secular change. The expansion / contraction suppression layer 24 may be provided closer to the adhesive layer 23 than the elastic deformation layer 22.

  In the above embodiment, the elastic deformation layer 22 is made of polyethylene resin, but it can also be made of polyurethane resin or poron resin. The thickness may be the same as when polyethylene resin is used.

  6 to 10 show other examples of connection shapes at both ends of the annular drip-proof band member 20 (20A). These examples are also proposed in Patent Document 1. In the example of FIG. 6, the butted end portion 48 and the butted end portion 52 of the annular drip-proof band member 20 (20 </ b> A) are the optical axis direction linear portion 49 corresponding to the optical axis direction linear portion 34 (optical axis direction linear portion 38). The optical axis direction linear part 53, the optical axis direction linear part 50 corresponding to the optical axis direction linear part 35 (optical axis direction linear part 39), the optical axis direction linear part 54, and the circumferential direction linear part 36 (circumferential direction straight line). A straight portion 51 and a straight portion 55 corresponding to the portion 40). Since the rear end position of the optical axis direction linear portion 49 (optical axis direction linear portion 53) and the front end position of the optical axis direction linear portion 50 (optical axis direction linear portion 54) are shifted back and forth, the linear portion 51 and the linear portion 55 inclines with respect to the circumferential direction. Since the butt end 48 and the butt end 52 having such a shape have a longer cutting distance than the butt end 33 and the butt end 37, the drip-proof effect is greater.

  The butt end portion 58 and the butt end portion 62 in FIG. 7 are an optical axis direction linear portion 59, an optical axis direction linear portion 63, and an optical axis direction straight line corresponding to the optical axis direction linear portion 34 (optical axis direction linear portion 38). Optical axis direction straight line portion 60, optical axis direction straight line portion 64 corresponding to portion 35 (optical axis direction straight line portion 39), circumferential curve portion 61 corresponding to circumferential direction straight line portion 36 (circumferential straight line portion 40), circumference A direction curve portion 65 is provided. The rear end position of the optical axis direction linear portion 59 (optical axis direction linear portion 63) and the front end position of the optical axis direction linear portion 60 (optical axis direction linear portion 64) are the same, and the circumferential curve portion 61 and the circumferential direction curve are the same. The part 65 is not a straight line but a curved line. The butt end portion 58 and the butt end portion 62 having such a shape have a longer cutting distance than the butt end portion 33 and the butt end portion 37 because the circumferential curve portion 61 and the circumferential curve portion 65 are curved. Accordingly, the drip-proof effect is larger as in the case of FIG.

  In the example of FIG. 8, the butted end portion 71 of the annular drip-proof band member 20 (20 </ b> A) has a linear shape that is inclined with respect to a direction parallel to the optical axis O. The butt end portion 70 and the butt end portion 71 having such a shape also have a cutting distance compared to a case where both ends of the annular drip-proof band member 20 (20A) are linearly cut in a direction perpendicular to the longitudinal direction. Since it is long, a large drip-proof effect can be obtained.

  In the example of FIG. 9, the cut surface shape of both butted ends 73 and 74 of the annular drip-proof band member 20 (20A) is a linear shape extending in a direction orthogonal to the longitudinal direction of the annular drip-proof band member 20 (20A). This is an example.

  In the example of FIG. 10, a liquid reservoir 66 is formed at an intermediate portion between the butted end portion 33 and the butted end portion 37 of the annular drip-proof band member 20 (20A). In this way, water droplets that have entered the gap between the butted end portion 33 and the butted end portion 37 from the front end of the optical axis direction linear portion 34 (optical axis direction linear portion 38) are optical axis direction linear portions 35 (optical axis direction). Reaching the rear end of the straight portion 39) can be more effectively prevented. It is of course possible to form the liquid reservoir 66 at the intermediate portion between the butt end portion 48 and the butt end portion 52 in FIG. 6 or the intermediate portion between the butt end portion 58 and the butt end portion 62 in FIG.

  In the present embodiment, the annular drip-proof band member 20 (20A) is provided between the inner annular member 11 and the outer annular member 12 that move relative to each other and move in the optical axis direction, but the lens barrel of the present invention. Of course, the drip-proof structure can be applied between the inner and outer annular members that perform only the relative rotational motion or only the relative linear motion.

10 lens barrel 11 inner annular member 12 outer annular member 13 annular space (annular gap)
14 annular groove (inwardly open annular groove)
15 annular groove (outwardly open annular groove)
20 20A Ring drip-proof material (strip)
21 Drip-proof layer (synthetic leather layer)
21a Raised surface 22 Elastic deformation layer 23 Adhesive layer 24 Stretch suppression layer O Optical axis

Claims (6)

An inner and outer annular member that is coaxial and relatively movable is provided, and one of the inner and outer annular members is bonded to one of the inner and outer surfaces of the annular drip-proof material, and the other circumferential surface is annular. In the drip-proof structure of the lens barrel in which the other surface inside and outside of the drip-proof band is in contact,
The annular drip-proof band material has a laminated structure of a drip-proof layer and an elastically deformable layer having a lower resilience than the drip-proof layer. The drip-proof structure of the lens barrel, wherein the drip-proof layer is in contact with the other peripheral surface of the inner and outer annular members. 2. The drip-proof structure for a lens barrel according to claim 1, wherein an annular groove for housing the annular drip-proof band material is formed in the annular member on the side to which the annular drip-proof band material is bonded, A layer protrudes radially outward from the annular groove, and a layer other than the drip-proof layer is a drip-proof structure of the lens barrel located in the annular groove. In water-resistant according to claim 1 or 2 lens barrel, wherein the elastic deformation layer is, polyethylene resin, polyurethane resin, drip-proof structure of the lens barrel that consists of either a Poron resin. The drip-proof structure for a lens barrel according to any one of claims 1 to 3, wherein the drip-proof layer is a drip-proof structure for a lens barrel in which a brushed surface is applied to the contact surface with the annular member. 5. The drip-proof structure of the lens barrel according to claim 1, wherein the annular drip-proof band material is further positioned on the elastic deformation layer side than the drip-proof layer, and is formed from the elastic deformation layer. A lens barrel drip-proof structure that includes a low-stretch, thin-walled stretch-reducing layer. In drip-proof structure of the lens barrel according to claim 5, wherein the expansion suppressing layer, PET resin, PC, polypropylene, resin sheet, drip-proof structure of the lens barrel that consists of either a resin film material.

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