Lens barrel, lens device and imaging device

Abstract

To provide, for example, a lens barrel advantageous in moving an optical element.SOLUTION: A lens barrel has: a linear guide member on which a linear guide extending along an optical axis is formed; a cam member in which a cam is formed; and a moving member that holds an optical element, includes an engaging member engaged with the linear guide and the cam, and moves along the optical axis through relative rotation between the linear guide member and the cam member. The engaging member includes a first engaging member that is engaged with the cam, and a second engaging member that is engaged with the linear guide and includes a flat surface in contact with the linear guide. The width of the first engaging member, the width of the cam, the width of the second engaging member, and the width W4 of the linear guide appropriately satisfy a relationship. A viscous member is arranged between the linear guide and the second engaging member.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a lens barrel, a lens device, and an imaging device. [Background technology]

[0002] In a mechanism (lens barrel) that moves a lens group in the optical axis direction by a cam and a cam follower, when an impact is applied, a dent caused by the cam follower may occur in the cam groove. In order to suppress such dents, a structure is known in which a flat portion is provided on the cam follower to increase the contact area between the cam follower and the cam groove and reduce the contact surface pressure. Also known is a structure in which a coil spring is provided between the cam groove and the cam follower to suppress rattle between the cam groove and the cam follower (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-53145 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Literature 1 In the structure disclosed in the above, vibrations caused by play between the cam follower and the groove may not be sufficiently reduced. For example, if the spring force is insufficient relative to the force acting on the cam follower, the lens group vibrates, causing the image formed through the lens group to shake.

[0005] An object of the present invention is to provide a lens barrel that is advantageous for moving optical elements, for example. [Means for solving the problem]

[0006] In order to solve the above problems, the lens barrel of the present invention includes a linear guide member having a linear guide extending along an optical axis, a cam member having a cam, and an optical element. Insideand a moving member including an engagement member that engages with the cam and that moves along the optical axis by relative rotation between the linear guide member and the cam member, the engagement member including a first engagement member that engages with the cam and a second engagement member that engages with the linear guide and has a flat surface that contacts the linear guide. a holding member that holds the second engagement member on the moving member so that a gap is formed between the linear guide and a flat surface of the second engagement member; between the first engagement member and the cam Gap Amount between the second engagement member and the linear guide Gap Amount The present invention is characterized in that the linear guide is smaller than the first engaging member and a viscous member is disposed between the linear guide and the second engaging member. Effect of the Invention

[0007] According to the present invention, for example, a lens barrel that is advantageous for moving an optical element can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of a lens barrel according to a first embodiment and a second embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 according to the first embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a detailed view B of FIG. 1 according to the first and second embodiments of the present invention. [Figure 4] FIG. 2 is a cross-sectional view taken along the line CC of FIG. 1 according to the first and second embodiments of the present invention. [Diagram 5] FIG. 10 is a diagram showing a detail B of FIG. 1 according to a second embodiment of the present invention. [Figure 6] FIG. 2 is a cross-sectional view taken along the line CC of FIG. 1 according to a second embodiment of the present invention. [Figure 7] FIG. 2 is a cross-sectional view taken along the line DD in FIG. 1 according to a second embodiment of the present invention. [Figure 8] FIG. 1 is a diagram showing an imaging device having a lens barrel of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. EXAMPLES

[0010] A lens barrel 1 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 4. Figure 1 shows an overall view of the lens barrel 1 in this embodiment.

[0011] The lens barrel 1 of this embodiment has a mechanism that allows the user to change the optical magnification by moving movable barrels (moving members) 2a and 2b having two zoom moving groups in the optical axis direction using a so-called cam mechanism. For convenience, the following describes a case where Example 1 is applied to the movable barrel 2a and Example 2 is applied to the movable barrel 2b.

[0012] 1, multiple lenses (optical elements) 3a and 3b are provided in lens barrel 1. Lens 3a has a convex shape and is fixed to movable barrel 2a by a lens holding structure such as a press ring or rivet (not shown). Similarly, lens 3b has a convex shape and is fixed to movable barrel 2b by a lens holding structure such as a press ring or rivet (not shown).

[0013] As shown in FIG. 1, lens barrel 1 is provided with a fixed barrel (linear guide member) 4, a cam ring (cam member) 5, three linear groove cam followers (second engagement members) 6 that displace movable barrel 2a in the optical axis direction, and three linear groove cam followers (second engagement members) 7 that displace movable barrel 2b in the optical axis direction.

[0014] 1, 2, and 4, the fixed barrel 4 has linear grooves (linear guides) 4a extending parallel to the optical axis direction, which are provided at three locations approximately equally spaced apart at 120 degree intervals around the optical axis. Orthogonal In the illustrated embodiment, the linear groove 4a is provided in a non-penetrating manner.

[0015] As shown in FIG. 1, the cam ring 5 has a substantially cylindrical shape, and the sliding surface 5a and the sliding surface 5b on the outer circumferential surface slide against the inner circumferential surface of the fixed barrel 4. The movement of the cam ring 5 in the optical axis direction is restricted by the fixed barrel 4 and a press ring fixed to the fixed barrel 4 with a screw. This allows the cam ring 5 to rotate around the optical axis. In addition, in this embodiment, the cam ring 5 having a substantially cylindrical shape is exemplified as the cam follower, but the shape of the cam follower is not limited to a substantially cylindrical shape, and may be an elliptical shape or a shape having a flat surface portion in contact with the cam groove. However, since the extension direction of the cam groove 5c with respect to the optical axis direction at the engagement portion of the cam follower changes, if the shape of the cam follower in the cross section normalized to the direction perpendicular to the optical axis is not a circle, it is fixed rotatably around the screw (holding member) 8.

[0016] The cam ring 5 is provided with three cam grooves (cams) 5c of the same shape for moving the movable barrel 2a, and three cam grooves 5d of the same shape for moving the movable barrel 2b. The cam grooves 5c and cam grooves 5d are provided at three locations that are approximately equally spaced about the optical axis. The movable barrel that holds the optical element moves along the optical axis due to the relative rotation between the fixed barrel and the cam ring as the cam followers engage with the linear grooves and cam grooves. Next, the structure around the straight groove cam follower 6 will be described with reference to FIGS.

[0017] As shown in FIG. 4, the linear groove cam follower 6 has a D-cut portion 6a which is a flat surface including a portion in surface contact with the wall surface of the linear groove 4a, and slides in surface contact with the wall surface of the linear groove 4a.

[0018] 3, the straight groove cam follower 6 abuts against a seat 2c provided on the movable lens barrel 2a, and is fixed to the movable lens barrel 2a by a screw (holding member) 8. A curved groove cam follower (first engagement member) 9 is provided between the D-cut portion 6a of the straight groove cam follower 6 and the seat 2c.

[0019] 3, the curved groove cam follower 9 has a cylindrical shape, and its inner peripheral surface is fitted into the straight groove cam follower 6, and its outer peripheral surface is in sliding contact with the cam groove 5c. The curved groove cam follower 9, the fixed barrel 4, the cam ring 5, and the straight groove cam follower 6 are constructed from different materials. The material of the curved groove cam follower 9 is resin, rubber, etc., and has a larger deformation amount when compressed than the materials of the fixed barrel 4, the cam ring 5, and the straight groove cam follower 6. It is preferable that the member of the curved groove cam follower 9 that comes into contact with the cam groove 5c has a smaller rigidity than the members that constitute the fixed barrel 4, the cam ring 5 (cam groove), and the straight groove cam follower 6.

[0020] As shown in Figure 3, there is a clearance S (S = |W2-W1|) between the width (diameter) W1 of the curved groove cam follower 9 and the width W2 of the cam groove 5c. As shown in Figure 4, there is a clearance T (T = |W4-W3|) between the width W3 of the straight groove cam follower 6 and the width W4 of the straight groove 4a. The clearances S and T are S <T (すなわち、|W2-W1|<|W4-W3|) The following condition is satisfied. The curved groove cam follower 9 may be press-fitted into the cam groove 5c, but in that case, the gap amount S will be zero or a negative value. In the case of the configuration shown in FIG. 3, the gap amount is 0 mm. <S<Tとなる。

[0021] The cam groove 5c and the curved groove cam follower 9 engage with each other to determine the position of the moving barrel 2b in the optical axis direction. The linear groove cam follower 6 and the linear groove 4a engage with each other to ensure the linearity of the moving barrel 2b in the optical axis direction. Furthermore, the linear groove cam follower 6 has at least one D-cut portion 6a (flat portion) that slides in surface contact with the wall surface of the linear groove 4a, thereby suppressing surface tilt. Here, since it is required to position the moving barrel 2b in the optical axis direction with higher accuracy so as to control the optical characteristics with high precision, the play between the cam groove 5c and the curved groove cam follower 9 is designed to take priority over the play between the linear groove cam follower 6 and the linear groove 4a. The play between the linear groove cam follower 6 and the linear groove 4a is designed so that it can absorb manufacturing errors. Therefore, as described above, the S <Tとなる。

[0022] Grease or lubricant is applied to the sliding surface of the linear groove 4a with the linear groove cam follower 6 to form a viscous film (viscous member) 10.

[0023] 3, curved groove cam follower 9 is in sliding contact with cam groove 5c, and linear groove cam follower 6 is in sliding contact with linear groove 4a via viscous film 10. As a result, when cam ring 5 rotates, movable barrel 2a moves in the optical axis direction, and the optical state of lens barrel 1 changes.

[0024] The movement of the movable lens barrel 2a in the optical axis direction is via the viscous resistance of the viscous film 10 between the straight groove cam follower 6 and the straight groove 4a, so even though there is play between the curved groove cam follower 9 and the cam groove 5c, free movement is restricted. Therefore, hunting of the control can be suppressed. In addition, even if the sliding area between the straight groove cam follower 6 and the straight groove 4a is large, it is possible to suppress an increase in sliding resistance and also to suppress wear of the sliding surface.

[0025] With the above configuration, the effect of the first embodiment is that the backlash is suppressed by providing the viscous film 10 between the straight groove cam follower 6 and the straight groove 4a. Also, by designing the play between the curved groove cam follower 9 and the cam groove 5c to be minimal, the behavior of the movable lens barrel 2a during movement is stabilized, making it possible to reduce shaking of the image.

[0026] In addition, compared to conventional technology, there is no need to configure a spring in the cam follower section, and it is only necessary to apply lubricant such as grease or lubricating oil to the linear groove, which makes assembly easier and reduces the number of parts. Also, when the mass of the moving group becomes heavier, it is possible to respond with a high degree of freedom by simply reducing the amount of backlash or changing the viscosity of the lubricant that forms the viscous film. EXAMPLES

[0027] Second Embodiment A lens barrel 1 according to a second embodiment of the present invention will now be described with reference to Figures 1 and 5 to 7. The structure of the cam follower portion differs from that of the first embodiment described above.

[0028] The structure around the linear groove cam follower 7 will be described with reference to FIGS. As shown in FIG. 6, the straight groove cam follower 7 has a D-cut portion 7a substantially parallel to the straight groove 4a, and slides against the straight groove 4a in surface contact.

[0029] 5, the straight groove cam follower 7 abuts against a seat 2d provided on the movable lens barrel 2b, and is fixed by a screw (holding member) 11. An intermediate member 12 and a curved groove cam follower 13 are provided between the D-cut portion 7a of the straight groove cam follower 7 and the seat 2d. The intermediate member 12 is cylindrical, with its inner peripheral surface being fitted with the straight groove cam follower 7, and its outer peripheral surface being fitted with or press-fitted into the curved groove cam follower 13. The curved groove cam follower 13 is cylindrical, with its outer peripheral surface being in sliding contact with the cam groove 5d.

[0030] The curved groove cam follower 13 is made of a material such as resin or rubber, and has a larger deformation amount during compression than the above-mentioned fixed barrel 4, cam ring 5, and straight groove cam follower 7. In other words, the curved groove cam follower 13 has a smaller rigidity than the fixed barrel 4, cam ring 5, and straight groove cam follower 7. The intermediate member 12 and cam groove 5d are made of a metal material having a similar linear expansion coefficient, such as aluminum, magnesium, or brass.

[0031] There is a clearance with a clearance amount Q (|W6 - W5|) between the width (diameter) W5 of the curved groove cam follower 13 and the width W6 of the cam groove 5d. There is a clearance with a clearance amount R (|W8 - W7|) between the width W7 of the straight groove cam follower 7 shown in FIG. 6 and the width W8 of the straight groove 4a. The magnitude relationship between the clearance amounts Q and R is Q < R. Note that the curved groove cam follower 13 may be press-fitted into the cam groove 5d. In that case, the clearance amount Q becomes zero. Note that in FIG. 5, for ease of understanding, the width (diameter) W5 of the curved groove cam follower 13 is described as the diameter of the component before being press-fitted into the cam groove 5d, so it should be noted that it does not represent the shape of the curved groove cam follower 13 in the actual assembled state. In the present embodiment, since the curved groove cam follower 13 is press-fitted and assembled into the cam groove 5d, the width (diameter) W5 of the curved groove cam follower 13 is equal to the width W6 of the cam groove 5d. The clearance amounts are Q = 0 mm, 0 mm < R (|W6 - W5| = 0 mm, 0 mm < |W8 - W7|).

[0032] Grease or lubricating oil is applied to the sliding surface of the straight groove 4a with the straight groove cam follower 7 to form a viscous film 10. Even if the sliding area between the straight groove cam follower 7 and the straight groove 4a is large, it is possible to suppress an increase in sliding resistance and also suppress wear of the sliding surface.

[0033] From FIGS. 5 and 7, the curved groove cam follower 13 is in sliding contact with the cam groove 5d, and the straight groove cam follower 7 is in sliding contact with the straight groove 4a via the viscous film 10. From this, when the cam ring 5 rotates, the moving lens barrel 2b moves in the optical axis direction, and the optical state of the lens barrel 1 changes.

[0034] In the second embodiment, by providing the intermediate member 12 with respect to the first embodiment, the thickness in the radial direction of the curved groove cam follower 13 is reduced. Since the curved groove cam follower 13 is made of a material different from that of the cam ring 5 and the straight groove cam follower 7, the linear expansion rate is different. In that case, by reducing the thickness in the radial direction of the curved groove cam follower 13, it is possible to reduce the amount of variation in the clearance amount Q between the curved groove cam follower 13 and the cam groove 5d during temperature change due to the different linear expansion rates.

[0035] As described above, in addition to the effects of the first embodiment, the second embodiment can stabilize the behavior of the movable lens barrel 2a during movement, including when the temperature changes, thereby making it possible to reduce shaking of the image.

[0036] In the above description, the lens barrel 1 is described as a zoom moving group, but the lens barrel 1 may be applied to any cam structure configured as a focus moving group, a relay group, or the like. In the embodiment, the relationship between the cam groove (cam) of the cam ring and the curved groove cam follower (engagement member) fixed to the moving lens barrel is exemplified as a configuration in which a cam having a concave structure engages with an engagement member having a convex structure. In addition, the relationship between the linear groove (linear guide) of the fixed barrel and the linear groove cam follower (engagement member) fixed to the moving lens barrel is exemplified as a configuration in which a linear guide having a concave structure engages with a linear groove cam follower (engagement member) having a convex structure. However, the present invention is not limited to these configurations. A cam having a convex structure such as a rail may be configured to engage with an engagement member having a concave structure. A linear guide having a convex structure may be configured to engage with a linear groove cam follower (engagement member) having a concave structure. In such a configuration, the widths of the cam, engagement member, and linear guide are defined as the widths of the engagement parts in both the case of the convex structure and the concave structure.

[0037] In the above description, the application of grease or lubricant between the cam groove 5c and the curved groove cam follower 9 and between the cam groove 5d and the curved groove cam follower 13 was not specified, but grease or lubricant may be applied to slide through a viscous film (viscous member). In this case, a different type of grease or lubricant may be applied to the cam groove than to the linear groove. In particular, it is preferable that the viscosity of the lubricant in the linear groove is higher than that of the lubricant used in the cam groove. This makes it possible to suppress hunting during drive control between the linear groove and the linear groove cam follower with a large gap, reduce wear between the cam groove and the cam groove cam follower with a small gap, and suppress an increase in sliding resistance, thereby realizing suitable drive control.

[0038] A lens device that enjoys the effects of the present invention can be realized by using the lens barrel of the embodiment. An imaging device that enjoys the effects of the present invention can be realized by using an imaging device 300 (FIG. 8) that has a lens device 100 that uses the lens barrel 101 of the embodiment and a camera device 200 that has an imaging element 201 that captures an image formed by the lens device 100.

[0039] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0040] 2: Moving telescope (moving part) 3: Lens (optical element) 4: Fixed tube (linear guide member) 4a: Straight groove (straight plan) Inside ) 5: Cam ring (cam component) 5c: Cam groove (cam) 6: Straight groove cam follower (second engagement member) 6a: D-cut section 9: Curved groove cam follower (first engagement member) 10: Viscous film (viscous material)

Claims

1. A linear guide member having a linear guide extending along the optical axis; A cam member having a cam formed thereon; a moving member that holds an optical element, includes an engaging member that engages with the linear guide and the cam, and moves along the optical axis by relative rotation between the linear guide member and the cam member; The engaging member includes a first engaging member that engages with the cam, and a second engaging member that engages with the linear guide and has a flat surface that contacts the linear guide; a holding member that holds the second engagement member on the moving member so that a gap is formed between the linear guide and a flat surface of the second engagement member, a gap between the first engaging member and the width of the cam is smaller than a gap between the second engaging member and the linear guide; A lens barrel, comprising: a viscous member disposed between the linear guide and the second engagement member.

2. 2. The lens barrel according to claim 1, wherein a portion of the first engagement member that comes into contact with the cam has a rigidity lower than a portion of the cam that comes into contact with the first engagement member.

3. 3. The lens barrel according to claim 2, wherein a portion of the first engagement member that comes into contact with the cam includes a resin.

4. 4. The lens barrel according to claim 1, wherein a gap between the second engagement member and the linear guide is greater than zero, and a gap between the first engagement member and the cam is zero.

5. 5. The lens barrel according to claim 1, wherein the viscous material contains a lubricant or a grease.

6. the moving member includes a holding member that holds the first engaging member and the second engaging member, 6. The lens barrel according to claim 1, wherein the first engaging member and the second engaging member are made of different materials.

7. A viscous member is disposed between the cam and the first engagement member, The telescope barrel according to any one of claims 1 to 6, characterized in that the viscous material disposed between the linear guide and the second engagement member has a higher viscosity than the viscous material disposed between the cam and the first engagement member.

8. An optical element; A lens device comprising: a lens barrel according to claim 1 that holds the optical element.

9. 9. An imaging device comprising: a lens device according to claim 8; and an imaging element for capturing an image formed by the lens device.

Images