JPH083571B2 - Lens barrel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lens barrel, and more particularly to a lens barrel for advancing and retracting a lens in an optical axis direction by fitting an inner helicoid ring and an outer helicoid ring. is there.

[Conventional technology]

A general lens barrel uses a helicoid screw to move a focus lens forward and backward in the optical axis direction to perform focus adjustment. The conventional lens barrel manufactures a helicoid ring suitable for the extended amount of the focus lens.

[Problems to be solved by the invention]

However, in the conventional lens barrel, when the lens barrel is the same and there is an inner helicoid ring and an outer helicoid ring with different shapes such as the lead, pitch, number of threads, and thread cutting direction of the helicoid screw portion of the helicoid ring, There is a case where a helicoid ring corresponding to the lens barrel is manufactured by molding or the like, and there is a problem in cost because each mold is manufactured.

In addition, since there are many similar parts, confusion in parts management may occur.

Therefore, an object of the present invention is to provide a lens barrel having a completely new helicoid ring, in which one kind of helicoid ring can be applied to a plurality of different lens barrels in order to eliminate the above-mentioned drawbacks of the conventional technique. is there.

[Means and Actions for Solving Problems]

In order to solve the above-mentioned problems, the present invention provides a lens barrel for advancing and retracting a lens in the optical axis direction by fitting an inner helicoid ring and an outer helicoid ring, wherein one of the inner helicoid ring and the outer helicoid ring is In order that the helicoid ring can guide a plurality of different helicoid rings as the other helicoid ring, the helicoid screw part has a mountain shape corresponding to the common part of the grooves of the helicoid screw parts of the different helicoid rings. The guide portion is formed, and one helicoid ring can be selectively fitted with a plurality of helicoid rings having different leads, pitches, numbers of threads, and thread cutting directions.

〔Example〕

Hereinafter, the present invention will be described with reference to the illustrated embodiments. In the embodiment of the present invention, the present invention is applied to the helicoid screw portion of the inner helicoid ring of the plurality of lenses.

1 to 6 show a first embodiment of the present invention. First
The figure is a cross-sectional view of the first lens barrel LA.

A fixed ring 2 is fixed to a lens mount 1 which is detachably attached to a camera mount (not shown). The outer ring 3 is fixed to the outer circumference of the fixed ring 2. A zoom ring 4 is fitted to the rear end portion of the outer peripheral surface of the outer ring 3 so as to be rotatable around the optical axis. The zoom ring 4 has a step portion 5 of the outer ring 3.
And the rear ring 6 fixed to the outer circumference of the lens mount 1 so as not to move in the optical axis direction. A rubber ring 7 is integrally provided on the outer periphery of the zoom ring 4 so as to prevent the photographer's finger from slipping during zooming.

A cam ring 8 is fitted on the outer peripheral surface of the fixed ring 2 so as to be rotatable around the optical axis. This cam ring 8 is regulated by a C ring 9 fixed to the tip of the outer peripheral portion of the fixed ring 2 and a collar portion 10 at the rear end of the outer peripheral portion of the fixed ring 2 so as not to move in the optical axis direction.

The cam ring 8 is connected to the zoom ring 4 by a zoom pin 11 so as to rotate together in the optical axis direction.

A gear ring 12 is fitted on the inner peripheral surface of the outer ring 3 so as to be rotatable around the optical axis. The gear ring 12 is restricted from moving in the optical axis direction by a stop ring 13 provided at the tip of the external appearance 3. A gear 14 is provided on the inner peripheral surface of the rear end of the gear ring 12. The gear 14 is interlocked with a gear mechanism (not shown) in the lens barrel, and is rotated by a coupler (not shown) provided on the camera body side and driven by a drive mechanism. A long groove 15 extending in the optical axis direction is formed on the inner front surface of the gear ring 12.

Further, an outer helicoid ring 16 having a large diameter on the front side is fitted to the inner peripheral surface of the fixed ring 2 so as to be movable in the optical axis direction at a small diameter portion on the rear side thereof. This outer helicoid ring 16
A helicoid screw portion 17 is provided on the inner peripheral surface of the front large diameter portion.

A roller 18 is planted on the outer peripheral surface of the outer helicoid ring 16, and the roller 18 is fitted in a cam groove provided in the cam ring 8 and a long groove provided in the fixed ring 2 and extending in the optical axis direction.

The rotation of the cam ring 8 is transmitted to the outer helicoid ring 16 as a back-and-forth movement by the roller 18.

The outer helicoid screw portion 17 is formed by the first lens group A1.
Is screwed with the helicoid screw portion 21 of the inner helicoid ring 20 that holds the lens ring 19 together with the lens ring 19. In this helicoid ring 20
Is a protrusion 22 that fits into the long groove 15 provided in the gear ring 12.
Is integrated with a drive ring 23 having a screw 24. A hood ring 25 is provided at the front end of the drive ring 23. That is, the inner helicoid ring 20 and the lens ring 19 holding the first lens group A1 can be moved forward and backward together with the drive ring 23 in the optical axis direction.

On the other hand, a lens ring is formed on the inner peripheral surface of the outer helicoid ring 16.
The second lens group A2 through the lens 26, and the fourth lens group A2 through the lens ring 27.
Second and fourth lens group moving rings 28 that hold the lens group A4 are fitted. A roller 29 is planted in the second / fourth lens group moving ring 28, and the roller 29 is provided in the outer helicoid ring 16 and is an escape groove provided so as not to interfere with the movement of the roller 29. It is fitted into a cam groove provided in the cam ring 8 and a long groove provided in the fixed ring 2 and extending in the optical axis direction.

This roller 29 causes the cam ring 8 to rotate in the second and fourth directions.
It is transmitted to the lens group moving ring 28 as back and forth movement.

A third lens group moving ring 30 is fitted on the inner circumference of the second and fourth lens group moving ring 28. The third lens group moving ring 30 holds the third lens ring A3 via the lens ring 31. A roller 32 is planted in the third lens group moving ring 30. The roller 32 is provided in the outer helicoid ring 16 and the second and fourth lens group moving rings 28, and a cam groove provided in the cam ring 8 through an escape groove which does not interfere with the movement of the roller 32. And is fitted in a long groove provided in the fixed ring 2 and extending in the optical axis direction. The rotation of the cam ring 8 is transmitted to the third lens group moving ring 30 as a back-and-forth movement by the roller 32. The third lens group moving ring 30 holds aperture blades, cornflowers, and cornflower stoppers.

 Next, the operation of the first lens barrel LA will be described.

When the zoom ring 4 is rotated around the optical axis, the zoom pin
The rotation is transmitted to the cam ring 8 by 11. The cam ring 8 rotates, and the cam groove provided in the cam ring 8 and the long groove extending in the optical axis direction provided in the fixed ring 2 cause the rollers 18, 2 to move.
9, 32 move back and forth, and the outer helicoid ring 16 moves in the optical axis direction to move the first lens group A1, and the second and fourth lens group moving rings 28 move in the optical axis direction to move the second and fourth lenses. group
The movement of A2, A4 and the third lens group moving ring 30 in the optical axis direction causes the third lens group A3 to move back and forth in the optical axis direction.

Next, during focusing, the rotation is transmitted to the gear 14 of the gear ring 12 by a coupler (not shown). This rotation is transmitted from the long groove 15 of the gear ring 12 to the projection 22 of the drive ring 23,
Since the drive ring 23 rotates integrally with the inner helicoid ring 20 and moves back and forth due to the helicoid coupling with the outer helicoid ring 16, a focusing operation is performed.

The movements of the respective lens groups A1 to A4 of the first lens barrel LA due to these operations are as shown in FIG. The state of the first lens barrel LA shown in FIG. 1 is on the telephoto side (symbol T in FIG. 2), and the zoom ring 4 (see FIG. 1) should be rotated around the optical axis. Thus, the state changes to the wide-angle side (symbol W in FIG. 2).

Here, when the focal length of the first lens barrel LA changes from the longest (telephoto state) to the shortest (wide-angle state), the moving amounts of the respective lens groups A1 to A4 are ΔA1, ΔA2, Δ
Assuming A3 and △ A4, △ A1 = 24.5mm △ A2 (△ A4) = -10.7mm △ A3 = 6.6mm (However, move from the position of each lens group on the telephoto side to the subject along the optical axis. If you want to be positive). Further, the amount ΔX of the movement of the first lens unit A1 for the focusing operation is ΔX = 1.8 mm from the infinite distance position to the closest distance position.

Next, FIG. 3 shows a sectional view of the second lens barrel LB.
Hereinafter, the second lens barrel LB will be described. However, the same parts as those of the first lens barrel LA are given the same reference numerals, and detailed description thereof will be omitted.

The small diameter portion of the outer helicoid ring 16 is fitted to the inner circumference of the fixed ring 2. A roller 33 is planted at the rear portion of the outer helicoid ring 16, and the roller 33 is provided with an optical axis provided on the cam ring 34 through a long groove provided on the fixed ring 2 and extending in the optical axis direction. It is fitted in a groove having an oblique angle with respect to.

The second lens group moving ring 35 is fitted in front of the inner circumference of the outer helicoid ring 16. This second lens group moving ring 35
Fixes the roller receiver 36. This roller receiver 36
Is fitted in a groove provided in the outer helicoid ring 16 and having an angle oblique to the optical axis. A roller 38 is integrally fitted to the roller receiver 36 via a spring 37, and a tip 39 of the roller 38 is pressed against a cam groove 40 provided on the inner peripheral surface of the fixed ring 2. , Is biased by a spring 37.
Further, the second lens group moving ring 35 holds the second lens group B2 via the lens ring 41.

A third lens group moving ring 42 is fitted behind the inner surface of the outer helicoid ring 16. In the third lens group moving ring 42,
A roller 43 is planted, and this roller 43 is provided with a cam groove provided in the cam ring 34 and a long groove extending in the optical axis direction provided in the fixed ring 2 via an escape groove provided in the outer helicoid ring. Has been inserted into. The third lens group moving ring 42 holds the third lens group B3 via the lens ring 44.

On the inner peripheral surface of the rear end of the fixed ring 2, a fourth lens ring 45 is provided.
The lens group B4 is held.

 Next, the operation of the second lens barrel LB will be described.

When the zoom ring 4 is rotated around the optical axis, the zoom pin
The rotation is transmitted to the cam ring 34 by 11. This cam ring
34 rotates, and first, the outer helicoid ring 16 and the third lens group moving ring 42 move back and forth by the cam groove and the roller. When the outer helicoid ring 16 moves back and forth, the second lens group moving ring
The roller 35 moves back and forth by the roller 38 and the cam groove 40.

Next, the rotation is transmitted to the gear 14 of the gear ring 12 by a coupler (not shown). This rotation is transmitted from the long groove 15 of the gear ring 12 to the projection 22 of the drive ring 23, and the drive ring 23 rotates integrally with the inner helicoid ring 20 and moves back and forth by the helicoid coupling with the outer helicoid ring 16. Therefore, the focusing operation is performed.

The movements of the respective lens groups B1 to B4 of the second lens barrel LB configured as described above are as shown in FIG. The state of the second lens LB shown in FIG. 3 is the state on the wide angle side (symbol W in FIG. 4). By rotating the zoom ring 4 (see FIG. 3), a state on the telephoto side (symbol T in FIG. 4) not shown in FIG. 3 is obtained.

Here, when the focal length of the second lens barrel LB changes from the shortest (wide-angle) to the longest (telephoto), the moving amount of each lens group B1 to B4 is calculated by ΔB1, ΔB2, ΔB3, Δ B4
Then, △ B1 = 25.4mm △ B2 = 4.1mm △ B3 = 20.3mm △ B4 = 0mm (However, when moving from the individual positions on the wide-angle side to the subject along the optical axis direction, it is positive) Becomes
Also, the amount of movement of the first lens unit B1 due to the focusing operation Δy
Is Δy = 5.5 mm from the infinite distance position to the very close position.

As described above in detail, in the first lens barrel LA and the second lens barrel LB, the lens mount 1, the fixed ring 2, the outer ring 3,
Zoom ring 4, rear ring 6, rubber ring 7, C ring 9, zoom pin 11,
Gear ring 12, retaining ring 13, outer helicoid ring 16, inner helicoid ring 2
The 0, drive ring 23, screw 24, hood ring 25, and other rollers can be commonly used.

However, the first lens barrel LA and the second lens barrel LB
And, since the amount of each first lens unit A1 and B1 to be extended, Δx and Δy from the infinite distance position to the close-up position are significantly different, the outer helicoid ring 16 and the inner helicoid ring 20
The helicoid screw parts 17 and 21 respectively provided on the common lead (the lead is temporarily aligned with the second lens barrel LB
24), the rotation of the gear ring 12 for extending the respective first lens groups A1 and B1 from the infinite distance position to the close distance position of the first lens barrel LA and the second lens barrel LB. The moving angle is 27 ° in the case of the first lens barrel LA and 82.5 ° in the case of the second lens barrel LB, and the backlash of the gear series of the coupler drive mechanism gives to the first lens barrel LA. The influence is about three times as much as the influence on the second lens barrel LB.

In order to eliminate this difference in influence, the shape of the inner helicoid ring 20 is set as shown in FIGS. 5 and 6. This will be described in detail below with reference to FIGS. 5 and 6.

FIG. 5 is a diagram in which the helicoid screw portion 21 provided on the outer peripheral surface of the inner helicoid ring 20 is developed on a plane. Sixth
The drawing is a cross-sectional view taken along the line AA in FIG.

The helicoid screw portion 21 of the inner helicoid ring 1 is provided with a helicoid screw 46 for the first lens barrel LA and a helicoid screw 47 for the second lens barrel LB in a superposed manner. Here, the LB helicoid screw 47 is the lead 2
4, if the LA helicoid screw 46 is the lead 8,
The rotation angle of the gear ring 12 for the full extension of the first lens barrel LA is 1.8 ÷ 8 × 360 = 81 °, and the rotation angle of the gear ring 12 for the full extension of the second lens barrel LB. Is 5.5 ÷ 24 × 360 = 82.5 °, and the influence of the gear backlash on the first lens barrel LA and the second lens barrel LB can be made almost the same.

With the above configuration, not only can one type of inner helicoid ring be shared by the first and second lens barrels LA and LB, but also the rotation resistance of the helicoid ring can be reduced. Becomes

Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8.

In the second embodiment, the configuration other than the helicoid screw portion 21 of the inner helicoid ring 20 of the first embodiment described above is completely the same, so a detailed description of the same portions will be omitted.

FIG. 7 shows the helicoid ring in the second embodiment of the present invention.
20 helicoid screw parts 48 are developed on a plane. Further, FIG. 8 is a sectional view of the helicoid screw portion 48, taken along the line BB.

49 is a helicoid screw for the first lens barrel LA, and 50 is a helicoid screw for the second lens barrel LB. The guide portion 51 surrounded by the LA helicoid screw 49 and the LB helicoid screw 50 is a guide portion surrounded by the helicoid screws 46 and 47 of the first embodiment, in which an acute angle portion is deleted. . With this configuration, the same action and effect as those of the first embodiment described above can be obtained, and since there is no acute angle portion, the helicoid screw when the outer helicoid ring and the inner helicoid ring are fitted It is possible to reduce the catch between the parts.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 and 10.

This third embodiment is similar to the second embodiment described above except that the configuration other than the helicoid screw portion 21 of the inner helicoid ring 20 is the first.
Since this is exactly the same as the embodiment, detailed description of the same parts will be omitted.

FIG. 9 shows the helicoid ring in the third embodiment of the present invention.
The helicoid screw portion 52 of 20 is developed on a plane. Further, FIG. 10 is a partially enlarged perspective view of the helicoid screw portion 52.

In FIGS. 9 and 10, 53 is a helicoid screw for the first lens barrel LA and 54 is a helicoid screw for the second lens barrel LB. The guide portion 55 surrounded by the LA helicoid screw 53 and the LB helicoid screw 54 has a substantially truncated cone shape as shown in FIG. With such a shape, the same operation and effect as those of the second embodiment described above can be obtained, and since the corner portions are reduced, the die cutting at the time of molding becomes very easy, Further, it becomes easy to process the die.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 11 and 12.

Similar to the second and third embodiments described above, this fourth embodiment is exactly the same as the first embodiment except for the helicoid screw portion 21 of the inner helicoid ring 20, so that the detailed description of the same portions will be omitted. The description is omitted.

FIG. 11 is a partially enlarged view of the helicoid screw portion 56 of the inner helicoid ring 20 according to the fourth embodiment of the present invention developed on a plane.

FIG. 12 is a partially enlarged perspective view of the helicoid screw portion 56.

Three types of helicoids 57,58,59 in Figs. 11 and 12
Have different leads and pitches. Thus, the guide portion 60 surrounded by the three types of helicoids 57, 58, 59 has the shape shown in the partially enlarged perspective view of FIG.

With such a shape, not only two kinds of different helicoid rings as described in the first to third embodiments but also three kinds of different helicoid rings are screwed to one inner helicoid ring. be able to. Of course, the guide part 60
Even if the same shape is changed as in the second and third embodiments with respect to the first embodiment, the second and third embodiments with respect to the first embodiment are performed. How the example works
The same action and effect as the effect can be obtained.

[Effects of the Invention] As described in detail above, according to the present invention, a plurality of helicoid screws having different lead, pitch, number of threads, thread cutting direction, etc. are respectively provided in one of the helicoid rings fitted to each other. By arranging so that they overlap each other on one surface, it is possible to selectively fit a helicoid ring having multiple helicoid threads with different leads, pitch, number of threads, thread cutting direction, etc. to one helicoid ring. (I) When manufacturing a helicoid ring by molding or the like,
Since the number of molds can be reduced, the cost of making molds can be reduced.

(Ii) Since similar parts are reduced, rationalization can be achieved in parts management.

(Iii) Since the shape of the helicoid screw portion of the one helicoid ring is intermittent, the rotational resistance at the time of fitting the helicoid ring is reduced.

 And so on.

[Brief description of drawings]

FIG. 1 is a sectional view of the first lens barrel LA in the first embodiment of the present invention, and FIG. 2 is the first lens group A1 to A1 of the first lens barrel LA.
4A and 4B are diagrams showing respective movements of the fourth lens unit A4 during zooming operation and focusing operation; FIG. 3 is a sectional view of a second lens barrel LB in the first embodiment of the present invention; Is the first lens group B1 to the second lens barrel LB
The figure which shows each movement of the 4th group lens B4 at the time of a zoom operation and a focus operation, FIG. 5 is a plane development view of the helicoid screw part of the inner helicoid ring in 1st Example, FIG. 6 is, Sectional drawing in the AA cross section in FIG. 5, FIG. 7 is a plane development view of the helicoid screw part of the inner helicoid ring in the 2nd Example of this invention, FIG. 8 is BB in FIG. Sectional drawing in section, FIG. 9 is a plane development view of the helicoid screw portion of the inner helicoid ring in the third embodiment of the present invention, FIG. 10 is a partially enlarged perspective view of FIG. 9, and FIG. FIG. 12 is a plan development view of the helicoid screw portion of the inner helicoid ring in the fourth embodiment, and FIG. 12 is a partially enlarged perspective view of FIG. 11. LA …… first lens barrel, LB …… second lens barrel, 16 …… outer helicoid ring, 20 …… inner helicoid ring, 21a …… guide part

Claims (1)

[Claims] 1. An inner helicoid ring and an outer helicoid ring provided so as to be screwed to each other, and holding means formed on the inner surface of the inner helicoid ring for selectively holding a plurality of lens systems. One of a helicoid thread or a helicoid thread groove formed by having a plurality of types of leads respectively corresponding to a plurality of lens systems on one of the circumferential surfaces of the inner helicoid ring and the outer helicoid ring facing each other, and the inner helicoid On the other of the peripheral surfaces of the ring and the outer helicoid ring facing each other, the other of the helicoid thread or the helicoid thread formed selectively corresponding to one of the plurality of types of leads, and A lens barrel characterized by that.