JPH09203845A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel which is increased in the use space on the outer periphery of its straight-moving guide cylinder and good in assembly. SOLUTION: This lens barrel is equipped with a 2-group lens chamber 11 which holds a 2-group lens 10 and is provided with a guide projecting part 11a on its outer peripheral surface, the straightmoving guide cylinder 6 which has an optical-axis directional guide groove 6c engaging the guide projecting part 11a and an optical-axis directional long hole 6d formed from the bottom surface to the outer peripheral surface of the guide groove 6c, a moving cylinder 3 which has a cam groove on its inner peripheral surface and is fitted onto the straight-moving guide cylinder 6, and a flange type seat 12a. Further, this lens barrel is equipped with a cam follower pin 12 which is implanted in the guide projecting part 11a and has its tip engaged with the cam groove of the moving cylinder 3 by penetrating the long hole 6d of the straight-moving guide cylinder 6d, and the width of the long hole 6d is made less than the diameter of the seat 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel of a camera.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing a conventional lens barrel. Reference numeral 2 is a fixed barrel attached to the camera body (not shown), and 2a and 2b are a female helicoid formed on the inner circumference of the fixed barrel 2 and a straight groove formed in the optical axis direction. Reference numeral 6 denotes a straight-moving guide cylinder, and a straight-moving key 6b that engages with the straight-moving groove 2b of the fixed barrel 2 is provided at an end of the straight-moving guide barrel 6 on the fixed barrel 2 side. The linear guide cylinder 6 has three notches 26c formed along the optical axis direction. Reference numeral 11 denotes a second lens group chamber in which the second lens group 10 is mounted,
After the cam follower pins 12 are planted in the holes 11c formed on the outer periphery of the second lens group chamber 11, the second lens group chamber 11 is moved so that the cam follower pins 12 and the notches 26c of the linear guide cylinder 6 engage with each other. It is stored in the straight guide cylinder 6.

Reference numeral 3 is a movable cylinder, and the fixed cylinder 2 is provided on the outer circumference thereof.
A male helicoid 3a that is screwed into the female helicoid 2a is formed, and a cam groove 3d (not shown) with which the tip of the cam follower pin 12 that is planted in the second lens group chamber 11 engages is formed on the inner circumference.
(See FIG. 5). The movable barrel 3 is rotatably attached to a linear guide barrel 6 in which the second group lens chamber 11 is housed. At that time, the cam follower pin 12 of the second group lens chamber 11 is attached so as to be engaged with the cam groove 3d of the movable barrel 3. In the movable barrel 3 to which the second group lens chamber 11 and the straight guide barrel 6 are attached, the straight key 6b of the straight guide barrel 6 is engaged with the straight groove 2b of the fixed barrel 2, and the male helicoid 3a is connected to the female helicoid 2a. It is attached to the fixed barrel 2 so as to be screwed. A female helicoid 3b is formed on the inner circumference of the moving barrel 3.
A first group cylinder (not shown) having a male helicoid screwed with b is attached to the movable cylinder 3.

When the movable barrel 3 is relatively rotated with respect to the fixed barrel 2 by a drive device (not shown), the movable barrel 3, the linear guide barrel 6 and the second group lens chamber 11 move integrally in the optical axis direction. At that time, the linear guide cylinder 6 and the second lens group chamber 11
Does not rotate relative to the fixed barrel 2, the cam follower pin 12 is guided by the cam groove 3d of the movable barrel 3, and the second group lens chamber 11 moves relative to the linear guide barrel 6 in the optical axis direction.

As described above, the cam follower pin 12 has a role of moving the second group lens chamber 11 in the optical axis direction, and as described below, the second group lens chamber 1 with respect to the optical axis.
It plays a role of accurately holding the position of 1 (that is, the second group lens 10). FIG. 5A is a view showing a cross section of the second lens group chamber 11, the moving barrel 3, and the linear guide barrel 6. The tip end of the cam follower pin 12 is engaged with the cam groove 3d of the moving barrel 3. At this time, the axis of the lens 10 tilts or shifts with respect to the optical axis as shown in FIG. 5B.
Need to be as small as possible. Therefore, it is necessary to manufacture the tip end of the cam follower pin 12 with high accuracy and closely contact with the cam groove 3d, and in order to suppress the play in the width direction between the cam follower pin 12 and the notch 26c, the diameter of the cam follower pin 12 is reduced. It was necessary to make the width dimension of the notch 26c accurate. Thus, the cam follower pin 1
Since 2 requires high dimensional accuracy, a metal cam follower pin is generally used, but there is a drawback that machining cost increases because it requires extremely high accuracy.

In order to eliminate such a defect, as shown in FIG. 6, a guide groove 6c formed along the optical axis direction on the inner circumference of the straight guide cylinder 6 and an outer circumference of the second lens group chamber 11 are formed. There is one that holds the position of the second group lens chamber 11 by engaging with the provided guide protrusion 21a. An elongated hole 26d is formed in the bottom surface of each guide groove 6c of the straight-travel guide cylinder 6 so as to penetrate in the outer peripheral direction of the straight-travel guide cylinder 6. The cam follower pin 12 has a guide projection 21.
a so that the guide groove 6c is engaged with the second lens group chamber 11a.
Is stored in the straight-travel guide cylinder 6 and then the straight-travel guide cylinder 6
Are planted in the holes 21c formed in the end surface 211a of the guide projection 21a from the outer peripheral side.

FIG. 7A is a sectional view showing in detail the planting portion of the cam follower pin 12, and FIG. 7B is a view showing the cam follower pin 12. The cam follower pin 12 is formed with a flange-shaped seat 12a.
Is supported by the end surface 211a of the guide projection 21a, so that the cam follower pin 12 is prevented from falling.
In the figure, d1 is the diameter of the cam follower pin 12, d2 is the diameter of the seat 12a, and d3 is the width of the slot 26d.

As described above, in the lens barrel shown in FIGS. 6 and 7, the guide projection 6a is accurately engaged with the guide groove 6c, so that the position of the second lens group chamber 11 and the guide are accurately maintained. Since the cam follower pin 12 is engaged with the cam groove 3b, the cam follower pin 12 only has to act to cam drive the second group lens chamber 11 in the optical axis direction. It does not matter if there is a gap (widthwise gap) between the two. Therefore, the dimensional accuracy of the cam follower pin 12 can be made looser as compared with the case of FIGS. 4 and 5, so that the cost can be reduced, and further, the cam follower pin 12 can be manufactured by plastic molding or the like. .

[0009]

By the way, in the space on the outer circumference of the straight guide cylinder 6, a flexible printed circuit board of a lens shutter provided in the lens barrel, a push rod for driving the lens barrier, etc. are arranged. ing. However, in the lens barrel of FIGS.
1 is housed in the linear guide cylinder 6, and then the cam follower pin 12 is inserted from the outside of the linear guide cylinder 6 into the guide projection 21a.
Since it is planted in the seat, it is necessary to make the width d3 of the slot 26d larger than the diameter d2 of the seat 12a. Therefore, there is a drawback that the usable space on the outer circumference of the straight-moving guide barrel 6 becomes small, and the outer shape of the lens barrel has to be made large in order to sufficiently secure this usable space. Further, when the linear guide cylinder 6 in which the second group lens chamber 11 is housed is attached to the movable cylinder 3, the cam follower pin 12 may fall out from the guide projection 21a, and the assembling property is not good.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrel which can increase the space available on the outer circumference of the linear guide barrel without increasing the outer diameter of the lens barrel and which is easy to assemble.

[0011]

To explain with reference to FIG. 1 showing an embodiment of the invention, the invention of claim 1 holds a lens 10 and is provided with a guide projection 11a on its outer peripheral surface. The lens chamber 11, the optical axis direction guide groove 6c formed on the inner peripheral surface and engaging with the guide projection 11a, and the optical axis direction elongated hole 6d formed from the bottom surface to the outer peripheral surface of the guide groove 6c. The straight guide cylinder 6 that is provided, and the cam cylinder 3 that has the cam groove 3d on the inner peripheral surface thereof and is externally inserted into the straight guide cylinder 6
And a flange-shaped seat 12a, the seat 12a is planted in the guide projection 11a so as to be supported by the mounting surface 111a of the guide projection 11a, and the tip thereof is long. The present invention is applied to a lens barrel that has a cam follower pin 12 that penetrates the hole 6d and is engaged with the cam groove 3d of the cam barrel 3 and that moves the lens chamber 11 in the optical axis direction in conjunction with the rotation of the cam barrel 3. , The width of the long hole 6d is the seat 12a
The above object is achieved by making the diameter smaller than.
In the lens barrel according to the invention of claim 2, the through hole 6e having a diameter larger than the diameter of the seat 12a is provided at either end of the elongated hole 6d.
Was formed.

In the lens barrel according to the first aspect of the invention, the usable space on the outer peripheral surface of the cam barrel 3 is increased by making the width of the elongated hole 6d smaller than the diameter of the seat 12a of the cam follower pin 12. In the lens barrel according to the second aspect of the present invention, the cam follower pin 12 is formed in the elongated hole 6d after the guide protrusion 11a of the lens chamber 11 is engaged with the guide groove 6c of the rectilinear guide barrel 6, and the through hole 6e is formed. It is planted in the guiding projection 11a of the lens chamber 11 through the through.

Incidentally, in the section of means for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments of the invention are used for the sake of easy understanding of the present invention. However, the present invention is not limited to the embodiment.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing a lens barrel of the present invention, and FIG. 2 is a sectional view of the lens barrel seen from the side. Reference numeral 4 denotes an optical axis. The upper side of the optical axis 4 is a diagram showing a case where the lens barrel is in a retracted state, while the lower side diagram of the optical axis 4 is a case where it is in a tele state. It is a figure. The same parts as those in FIGS. 4 to 7 are designated by the same reference numerals, and the duplicated description will be omitted.

Recesses 11b are formed on the end surfaces 111a of the guide projections 11a provided in the second group lens chamber 11, and holes 111c into which the cam follower pins 12 are planted are provided on the bottom surface 111b of each recess 11b. There is. An elongated hole 6d penetrating in the outer peripheral direction of the straight guide cylinder 6 is formed on the bottom surface of each guide groove 6c of the straight guide cylinder 6, and a through hole 6e is formed at the end of each elongated hole 6d on the moving cylinder 3 side. Are formed respectively. The width of the long hole 6d is 12 for the cam follower pin.
Is smaller than the outer diameter of the seat 12a, while the diameter of the through hole 6e is larger than the outer diameter of the seat 12a.
In the second group lens chamber 11, the guide projection 11a has the guide groove 6
After being attached to the straight guide cylinder 6 so as to be engaged with c, the hole 111c of the guide protrusion 11a is aligned with the position of the through hole 6e of the elongated hole 6d, and the cam follower pin 12 is attached to the outer peripheral side of the straight guide cylinder 6. Through hole 6e through hole 111
plant in c. In the normal operation after the lens barrel is assembled, the cam follower pin 12 does not come to the position of the through hole 6e, and the cam follower pin 12 does not fall out.

As shown in FIG. 2, a claw 3c is formed at the rear end of the moving barrel 3, and the claw hooking portion 6 of the linear guide cylinder 6 is provided.
a is rotatably engaged with respect to the optical axis 4. As a result, the straight guide cylinder 6 is rotatable relative to the movable cylinder 3, but its movement in the optical axis direction is restricted by the claw 3c.

In FIG. 2, reference numeral 5 denotes a first group cylinder attached to the left side of the movable cylinder 3 in the drawing, and a male helicoid 5a screwed with a female helicoid 3b of the movable cylinder 3 is formed on the outer periphery of the first group cylinder 5. There is. By rotating the movable barrel 3 relative to the fixed barrel 2, the first group barrel 5 moves in the optical axis direction, but since a rotation prevention mechanism (not shown) is provided between the first barrel 5 and the straight guide barrel 6, the straight guide is not provided. It does not rotate relative to the cylinder 6.
Reference numeral 7 denotes a shutter housed in the first group cylinder 5, and the shutter 7 has a first group lens 8 attached thereto. The shutter 7 is attached to the shutter stop portion 5b of the first group cylinder 5 with a screw 9. Reference numeral 1 is a part of the camera body.

In the retracted state, when the movable barrel 3 is rotated relative to the fixed barrel 2 by a predetermined value in a predetermined direction by a driving device (not shown), the movable barrel 3 is extended to the left side by the helicoids 3a and 2a. At this time, the cam follower pin 12 of the second group lens chamber 11 and the cam groove 3d of the movable barrel 3
And the male helicoid 5a of the first group barrel 5 and the female helicoid 3b of the movable barrel 3 are screwed together, and they are respectively extended to the left side in the figure and telescopic as shown below the optical axis 4. Becomes

FIG. 3 is an enlarged view of a planting portion of the cam follower 12 shown in FIG. 2, and FIG. 3B is a sectional view taken along line AA of FIG. The guide projection 11a of the second group lens chamber 11 engages with the guide groove 6c of the linear guide cylinder 6, while the cam follower pin 12 penetrates the elongated hole 6d and engages with the cam groove 3d of the movable cylinder 3. There is. The cam follower pin 12 is planted in the guide projection 11a so that the seat 12a is supported by the bottom surface 111b of the recess 11b. In the figure, since the depth dimension of the recess 11b is set to be larger than the thickness dimension of the seat 12a, the seat 12a does not protrude in the outer peripheral direction from the end surface 111a of the guide projection 11a. Further, the width dimension d3 of the elongated hole 6d is slightly larger than the diameter d1 of the cam follower pin 12, and the diameter d of the seat 12a of the cam follower pin 12 is large.
It is set smaller than 2.

In the embodiment of the invention described above, the width dimension d3 of the elongated hole 6d of the straight guide cylinder 6 is set to the cam follower pin 12.
Since the diameter is reduced to about d1, the straight guide tube 6
The available space on the outer periphery of the flexible printed circuit board is increased, and the flexible printed circuit board and the like can be arranged more easily than in the conventional case. Further, since the recess 11b is formed in the end surface 111a of the guide projection 11a and the cam follower pin 12 is implanted, the recess 11b is formed.
As compared with the case where the cam follower pin 12 is implanted in the end surface 111a without forming the groove, the wall thickness t of the bottom surface portion of the guide groove 6c is increased.
1 (see FIG. 3) can be enlarged, and the guide groove 6c
Further, it is possible to prevent the strength of the tubular portion of the linear guide tube 6 from decreasing due to the formation of the elongated hole 6d. In addition, since the diameter of the seat 12a of the cam follower pin 12 is larger than the width of the elongated hole 6d, there is no possibility that the cam follower pin 12 will fall out during the lens barrel assembly, and the assemblability is improved.

Further, as shown in FIG. 4, when the notch 26c is formed in the rectilinear guide cylinder 6, the strength of the cylinder portion of the rectilinear guide cylinder 6 decreases, but in the embodiment of the present invention, it is used for guiding. Since the cam follower pin 12 is planted in the guide projection 11a of the lens chamber 11 through the through hole 6e formed at the end of the elongated hole 6d after the projection 11a is engaged with the guide groove 6c, it is described above. Such drawbacks can be eliminated.

In the correspondence between the above-described embodiment of the invention and the scope of the claims, the second group lens 10 is a lens, the second group lens chamber 11 is a lens chamber, the moving barrel 3 is a cam barrel, and the end face 111a is attached. Configure each face.

[0023]

As described above, according to the present invention,
Since the width of the long hole of the straight guide tube through which the cam follower pin passes is smaller than the diameter of the seat of the cam follower pin, the width of the long hole can be reduced to about the diameter of the cam follower pin, and the outer diameter of the lens barrel can be increased. It is possible to increase the usable space on the outer circumference of the straight-ahead guide cylinder without any increase.
Further, there is no possibility that the cam follower pin will fall out when the lens barrel is assembled, and the assemblability is improved. Particularly, in the lens barrel of the invention of claim 2, since the cam follower pin is planted in the guide protrusion through the through hole formed at the end of the elongated hole, the cam follower pin planted in the guide protrusion is It is not necessary to form the through hole to the end of the straight guide cylinder, and it is possible to avoid a decrease in strength of the straight guide cylinder.

[Brief description of drawings]

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

FIG. 2 is a sectional view of the lens barrel shown in FIG.

3 is an enlarged view of a planting portion of the cam follower pin 12 shown in FIG. 2, and FIG. 3B is a sectional view taken along line AA of FIG.

FIG. 4 is a diagram showing a first example of a conventional lens barrel.

FIG. 5 is a diagram illustrating a cam follower pin, (a)
Is a sectional view, (b) and (c) are optical axes and the second group lens 10
FIG. 5 is a diagram showing the relationship with the axis of.

FIG. 6 is a diagram showing a second example of a conventional lens barrel.

7 is an enlarged view of a planting portion of the cam follower pin 12 in FIG. 6, and FIG. 7B is a view showing the cam follower pin 12.

[Explanation of symbols]

 2 fixed tube 3 moving tube 3d cam groove 6 straight guide tube 6c guide groove 6d long hole 6e through hole 10 second group lens 11 second group lens chamber 11a guide projection 11b recess 12 cam follower pin 12a seat 111a end surface 111b bottom surface

Claims (2)

[Claims] 1. A lens chamber for holding a lens, wherein a guide protrusion is provided on an outer peripheral surface, an optical axis guide groove formed on an inner peripheral surface and engaging with the guide protrusion, and A straight guide cylinder having an elongated hole in the optical axis direction formed from the bottom surface of the guide groove to the outer peripheral surface, a cam cylinder having a cam groove on the inner peripheral surface and externally inserted in the straight guide cylinder, and a flange-shaped seat. And the seat is planted in the guide projection so as to be supported by the mounting surface of the guide projection, and the tip of the seat penetrates the elongated hole of the straight guide cylinder to allow the cam to move. In a lens barrel having a cam follower pin engaged with a cam groove of a cylinder and moving the lens chamber in the optical axis direction in conjunction with rotation of the cam cylinder, a width of the slot is smaller than a diameter of the seat. A lens barrel characterized by the above. 2. The lens barrel according to claim 1, wherein a through hole having a diameter larger than the diameter of the seat is formed at one end of the elongated hole.