JP2760243B2 - Zoom lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel which is used in an image pickup apparatus such as an infrared ray detection apparatus which detects infrared rays and generates a signal, and which changes a minimum photographing distance with zooming. is there.

[0002]

FIG. 12 is a sectional view showing a conventional zoom lens barrel for an infrared detecting device. In the figure, 1 is a first movable lens group, and 2 is a second movable lens group. Generally, the first movable lens group is a variator and constitutes a zoom lens group, and the second movable lens group is a convencator and constitutes a focus lens group. 3 is a first movable frame, 4 is a second movable frame, the first movable frame 3 holds the first movable lens group 1, and the second movable frame 4 is the second movable lens group 2 Holding. Reference numeral 5 denotes a first cam pin, which is attached to the first movable frame 3, and reference numeral 6 denotes a second cam pin, which is attached to the second movable frame 4. Reference numeral 7 denotes a fixed frame which is fixed to the main body 9 by screws 8. The fixed frame 7 has two grooves in the optical axis direction, 10 is a first groove, and the first cam pin 5 is inserted therein.
Reference numeral 1 denotes a second groove in which the second cam pin 6 is inserted, and a first movable lens group 1 and a second movable lens group 2
The direction of rotation is regulated. Reference numeral 12 denotes an inner cylinder of the fixed frame 7, which engages with the outer cylinder 13 of the first movable frame 3 and the outer cylinder 14 of the second movable frame 4 to serve as a guide when movable. Reference numeral 15 denotes a cam ring, which is a motor 1
7 performs a rotational movement. However, the optical axis is positioned by the fixed frame 7 and the main body 9. Cam ring 1
5 has a first cam groove 18 and a second cam groove 19, a first cam pin 5 is inserted into the first cam groove 18, and a second cam pin 6 is inserted into the second cam groove 19. Has been inserted. FIG. 13 is an external view of the fixed frame 7 and the cam ring 15. The shapes of the first groove 10 and the second groove 11 in the fixed frame 7 and the first cam groove 18 and the second
The shape of the cam groove 19 is shown in FIG. Reference numeral 20 denotes a mount that engages with the infrared detection device, and is attached to the main body 9 by screws 18.

[0003] A conventional zoom lens barrel for an infrared detector is constructed as described above. Next, the operation will be described. When the motor 17 rotates according to a zooming signal, the rotational force is transmitted to the cam ring 15 via the gear 16 and the cam ring 15 rotates. The cam ring 15 has a first cam groove 18 and a second cam groove 19, and each cam groove also rotates. Since the first cam pin 5 is inserted into the first cam groove 18 and the second cam pin 6 is inserted into the second cam groove 19, the first cam pin 5 and the second cam pin 6 Rotational force is applied. However, since the first cam pins 5 are also inserted into the first grooves 10 of the fixed frame 7 and the second cam pins 6 are also inserted into the second grooves 11 of the fixed frame 7, rotation is restricted. Therefore, it receives a moving force in the optical axis direction along each cam groove without rotating. With this moving force, the first movable frame 3 and the second movable frame 4 are moved to predetermined positions by using the inner cylinder 12 of the fixed frame 7 as a guide, and an optical system is formed on the telephoto side and the wide-angle side.

[0004]

The above-mentioned conventional zoom lens barrel for an infrared detecting device has the following problems to be solved. The wavelength band of the light normally used for the infrared detecting device is 3 to 5 μm or 8 to 12 μm. In order to detect the light with high accuracy, the positional accuracy in the radial direction of the lens must not be largely deviated from the wavelength dimension and must be strictly controlled. There is. Furthermore, in a system that uses an infrared detector to track a distant aircraft, etc., when a detected object is captured on the wide-angle side and zoomed to the telephoto side, the position of the detected object changes due to a radial displacement of the lens. Therefore, it is not possible to track the detected object, so that it does not function as a tracking system, and it is necessary to strictly control the radial positional accuracy of the lens on the wide-angle side and the telephoto side.

However, in the conventional zoom lens barrel for an infrared detecting device, the first movable lens group and the second movable lens group 2 are moved by the inner cylinder 12 of the fixed frame 7 as a guide. 3 and the second movable frame 4 are moved, the positional accuracy of the lens in the radial direction is determined by the dimensional accuracy of the inner cylinder 12 of the fixed frame 7 and the outer cylinder 1 of the first movable frame 3.
The clearance is determined by the dimensional accuracy of the outer cylinder 14 of the third and second movable frames 4. Since the sliding portion is a sliding slide, if the clearance is made small, the frictional force becomes large and the sliding becomes impossible. Therefore, a large clearance is absolutely necessary, and the positional accuracy of the lens in the radial direction is deteriorated. Further, the inner cylinder 12 of the fixed frame 7, the outer cylinder 13 of the first movable frame 3,
The clearance of the outer cylinder 14 of the movable frame 4 cannot be adjusted only by assembling after processing, and the clearance has a large variation.

The present invention has been made to solve such a problem. By changing the conventional sliding method by sliding, the inner cylinder 12 of the fixed frame 7 and the outer cylinder 13 of the first movable frame 3 are removed. to reduce the gap between the second outer cylinder 14 of the movable frame 4, and an object thereof is to obtain's Murenzu barrel positional accuracy in the radial direction was improved lenses.

[0007]

The roller bearing arranged on the sliding part in the SUMMARY OF THE INVENTION The engagement Luz Murenzu barrel to the present invention, to reduce the gap by changing the sliding rolling from slipping sliding,
This is to improve the positional accuracy of the lens in the radial direction.

According to the present invention, the position of the roller bearing can be adjusted by the eccentric pin when assembling, so that variations in the clearance can be suppressed regardless of the processing accuracy.

Further, a roller bearing arranged on the sliding portion in engagement Luz Murenzu barrel to the present invention, to reduce the frictional forces changing the sliding rolling from slipping sliding and fixing the roller bearing by the force of the coil spring The gap is eliminated by pressing the lens against the inner cylinder of the frame, and the positional accuracy of the lens in the radial direction is improved.

Further, according to the present invention, the position of the roller bearing is adjusted by a tapered plate or a floating nut and a screw shaft at the time of assembly.

[0011]

In the present invention, the first movable frame 3 and the second movable frame 3
The roller bearing is attached to the movable frame 4 of the above, and the inner cylinder 12 of the fixed frame 7 is engaged by the roller bearing. Therefore, the sliding is changed from the sliding to the rolling. Even if the clearance is reduced, the frictional force does not increase. slidable, as a result's Murenzu barrel with improved positional accuracy in the radial direction of the lens is obtained.

In the present invention, a roller bearing is mounted on the first movable frame 3 and the second movable frame 4 via a coil spring, and is engaged with the inner cylinder 12 of the fixed frame 7 by a roller bearing. eliminating the gap between the sliding portion by the force, as a result's Murenzu barrel with improved positional accuracy in the radial direction of the lens is obtained.

[0013]

【Example】

Embodiment 1 FIG. FIG. 1 is a sectional view showing one embodiment of the present invention. In the figure, 1 to 21 are the same as those of the conventional apparatus. 2
Reference numeral 2a denotes a roller bearing unit, and three or more sets are mounted on the outer periphery of the first movable frame 3 and the second movable frame 4 at equal positions.

FIG. 2 is a sectional view of the roller bearing unit 22 of the present invention. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion on the outer periphery is engaged with the inner cylinder 12 of the fixed frame 7. The roller bearing unit 22a has two roller bearings 23, and the two roller bearings 23 are arranged in the optical axis direction to prevent the lens from tilting in the optical axis direction . An eccentric pin 24 engages the roller bearing 22 with the bracket 25.

FIG. 3 is a sectional view of the eccentric pin 24. As shown in this figure, the eccentric pin 24 is eccentric between the engaging portion of the roller bearing 23 and the fitting portion of the bracket 25. Reference numeral 26 denotes a nut, which fixes the eccentric pin 24 to the bracket 25. Reference numeral 27 denotes a screw which is used to hold the bracket 25 to the first movable frame 3.
And attached to the second movable frame 4.

In the zoom lens barrel for an infrared detecting device configured as described above, the inner cylinder 12 of the fixed frame 7 engages with the spherical portion on the outer periphery of the roller bearing 23, and rolls and slides when the lens moves. Therefore, even if the clearance of the sliding portion is reduced, the frictional force does not increase, and the positional accuracy of the lens in the radial direction can be improved.

When the eccentric pin 24 is rotated during assembly, the engaging portion of the roller bearing 23 of the eccentric pin 24 and the fitting portion of the bracket 25 are eccentric.
The engaging portion of the roller bearing 23 is eccentric with respect to the fitting portion 5 and is moved in the radial direction of the inner cylinder 12 of the fixed frame 7 of the roller bearing 23 to adjust the clearance between the roller bearing 23 and the inner cylinder of the fixed frame 7. be able to. If the eccentric pin 24 is fixed to the bracket 25 with the nut 26 after the adjustment, the clearance between the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 does not change thereafter. As described above, the gap can be controlled to be constant irrespective of the processing accuracy of the component, and the variation in the gap can be suppressed.

Embodiment 2 FIG. FIG. 4 is a sectional view showing Embodiment 2 of the present invention. In the figure, 1 to 21 are the same as those of the conventional apparatus. Reference numeral 22b denotes a roller bearing unit, which is mounted on the outer periphery of the first movable frame 3 and the second movable frame 4 at three or more equal positions.

FIG. 5 shows a roller bearing unit 22b according to the present invention.
FIG. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion on the outer periphery is engaged with the inner cylinder 12 of the fixed frame 7. The roller bearing unit 22b has two roller bearings 23, and the two roller bearings 23 are arranged in the optical axis direction to prevent the lens from tilting in the optical axis direction. Reference numeral 24 denotes a pin which engages the roller bearing 23 with the bracket 25. 2
Reference numeral 8 denotes a retaining ring, which fixes the pin 24 to the bracket 25. 29 is a guide shaft, and the bracket 25
Is supported. Reference numeral 30 denotes a guide hole which engages with the guide shaft 29 to determine the position of the roller bearing unit 22b. Reference numeral 31 denotes a coil spring, and the guide shaft 29 and the bracket 2 are driven by the force of the coil spring 31.
5, the roller bearing 23 is pressed against the inner cylinder 12 of the fixed frame 7.

In the zoom lens barrel of the infrared detecting device constructed as described above, the inner cylinder 12 of the fixed frame 7 engages with the spherical portion on the outer periphery of the roller bearing 23, and the force of the coil spring 31 causes the roller bearing 23. Are pressed against the inner cylinder 12 of the fixed frame 7 to eliminate the clearance of the sliding portion. When the lens moves, the roller slides, so that even if there is no clearance in the sliding portion, the frictional force does not increase, and the positional accuracy of the lens in the radial direction can be improved.

The roller bearing 23 includes a coil spring 31.
Is pressed against the inner cylinder 12 of the fixed frame 7 by the force of the above, so that the clearance of the sliding portion is eliminated. Therefore, even if the processing accuracy of the inner cylinder 12 of the fixed frame 7 is poor, the clearance can always be eliminated. . As described above, the clearance can be eliminated regardless of the processing accuracy of the component, and the positional accuracy of the lens in the radial direction can be improved.

Embodiment 3 FIG. FIG. 6 is a sectional view showing Embodiment 3 of the present invention. In the figure, 1 to 21 are the same as those of the conventional apparatus. Reference numeral 22c denotes a roller bearing unit, which is mounted on the outer periphery of the first movable frame 3 and the second movable frame 4 at three or more equal positions.

FIG. 7 shows a roller bearing unit 22c according to the present invention.
FIG. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion on the outer periphery is engaged with the inner cylinder 12 of the fixed frame 7. The roller bearing unit 22c has two roller bearings 23, and the two roller bearings 23 are arranged in the optical axis direction to prevent the lens from tilting in the optical axis direction. Reference numeral 24 denotes a pin, which engages the roller bearing 23 with the bracket 25.
A retaining ring 28 fixes the pin 24 to the bracket 25. 32 is a first taper plate, and 33 is a second taper plate. First taper plate 32
And the second taper plate 33 have the same taper angle,
The respective tapered surfaces are in contact in opposite directions. Reference numeral 34 denotes a screw, which attaches the bracket 25, the first tapered plate 32, and the second tapered plate 33 to the first movable frame 3 and the second movable frame 4. An adjustment screw 35 presses the outer peripheral portion of the first taper plate 32 in a direction perpendicular to the optical axis.

FIG. 8 shows a roller bearing unit 22c of the present invention.
FIG. As shown in FIG. 7 and FIG. 8, the four outer peripheral portions of the bracket 25 and the second tapered plate 33
With the movable frame 3 and the second movable frame 4 so as not to shift in the optical axis direction and the direction perpendicular to the optical axis. The first taper plate 32 is engaged with the first movable frame 3 and the second movable frame 4 only at the outer peripheral portion in the optical axis direction, so that the first taper plate 32 does not shift in the optical axis direction. The outer peripheral portion of the first tapered plate 32 in a direction perpendicular to the optical axis has a clearance with the first movable frame 3 and the second movable frame 4 so that the first tapered plate 32 can be moved.

In the zoom lens barrel for an infrared detecting device constructed as described above, the inner cylinder 12 of the fixed frame 7 engages with the spherical portion on the outer periphery of the roller bearing 23, and rolls when the lens moves. Therefore, even if the clearance of the sliding portion is reduced, the frictional force does not increase, and the positional accuracy of the lens in the radial direction can be improved.

When the outer peripheral portion of the first tapered plate 32 in the direction perpendicular to the optical axis is pushed by the adjusting screw 35 at the time of assembly, the first tapered plate 32 moves on the optical axis of the second tapered plate 33. And move at right angles. When the first taper plate 32 moves in a direction perpendicular to the optical axis, the bracket 25 is pushed up in the radial direction of the inner cylinder 12 of the fixed frame 7, and the roller bearing 23 is moved in the radial direction of the inner cylinder 12 of the fixed frame 7, The clearance between the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 can be adjusted. If the bracket 25, the first taper plate 32, and the second taper plate 33 are fixed by the adjusted screws 34, the clearance between the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 does not change thereafter. As described above, the gap can be controlled to be constant irrespective of the processing accuracy of the component, and the variation in the gap can be suppressed.

Embodiment 4 FIG. FIG. 9 is a sectional view showing Embodiment 4 of the present invention. In the figure, 1 to 21 are the same as those of the conventional apparatus. Reference numeral 22d denotes a roller bearing unit, which is mounted on the outer periphery of the first movable frame 3 and the second movable frame 4 at three or more equal positions.

FIG. 10 shows the roller bearing unit 22 of the present invention.
It is sectional drawing of d. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion on the outer periphery is engaged with the inner cylinder 12 of the fixed frame 7. The roller bearing unit 22 has two roller bearings 23, and the two roller bearings 23 are arranged in the optical axis direction to prevent the lens from tilting in the optical axis direction. Reference numeral 24 denotes a pin which engages the roller bearing 23 with the bracket 25. 2
A retaining ring 8 fixes the pin 24 to the bracket 25. A screw shaft 36 is fixed to the bracket 25. Reference numeral 37 denotes a floating nut which meshes with the screw shaft 36 and is engaged with the first movable frame 3 and the second movable frame 4 by a retaining ring 38 so as not to move in the axial direction. However, rotation around the axis is possible. Reference numeral 39 denotes a fixed nut. By tightening the fixed nut, a double nut effect is obtained with the floating nut 37, and the nut acts as a loosening stop of the floating nut 37. Reference numeral 40 denotes a retaining ring insertion hole, which is provided in the first movable frame 3 and the second movable frame 4, and is inserted using the hole 40 when the retaining ring 38 is assembled into the floating nut 37.

FIG. 11 shows a roller bearing unit 22 according to the present invention.
It is a side view of d. As shown in FIGS. 10 and 11, the four surfaces of the outer peripheral portion of the bracket 25 are engaged with the first movable frame 3 and the second movable frame 4 so as not to shift in the optical axis direction and the direction perpendicular to the optical axis. Has become.

In the zoom lens barrel for an infrared detecting device configured as described above, the inner cylinder 12 of the fixed frame 7 engages with the spherical portion on the outer periphery of the roller bearing 23, and rolls and slides when the lens moves. Therefore, even if the clearance of the sliding portion is reduced, the frictional force does not increase, and the positional accuracy of the lens in the radial direction can be improved.

At the time of assembly, the floating nut 37
, The floating nut 37 becomes a retaining ring 38
As a result, the screw shaft 36 meshing with the floating nut 37 is moved in the axial direction. When the screw shaft 36 moves in the axial direction, the bracket 25 is pushed up in the radial direction of the inner cylinder 12 of the fixed frame 7, and the roller bearing 23 is moved in the radial direction of the inner cylinder 12 of the fixed frame 7, and the roller bearing 23 and the fixed frame 7 are moved. Of the inner cylinder 12 can be adjusted. By tightening the fixed nut 39 after the adjustment, the floating nut 37 and the double nut effect are obtained, the floating nut 37 is not loosened, and then the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 are adjusted.
The gap does not change. As described above, the gap can be controlled to be constant irrespective of the processing accuracy of the component, and the variation in the gap can be suppressed.

In the above embodiment, the zoom lens barrel for the infrared detecting device has been described, but the present invention is not limited to the infrared detecting device.

[0033]

According to the present invention, the fixed frame 7 is provided by the roller bearing 23.
By engaging with the inner cylinder 12 and rolling and sliding when moving the lens, the clearance of the sliding portion can be reduced, and the positional accuracy of the lens in the radial direction can be improved. In addition, since the position of the roller bearing 23 can be adjusted at the time of assembly by the adjusting member,
The gap can be maintained constant regardless of the processing accuracy of the parts, and the variation in the gap can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a roller bearing unit according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing the eccentric pin of the present invention.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a roller bearing unit according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a sectional view showing a roller bearing unit according to a third embodiment of the present invention.

FIG. 8 is a side view showing a roller bearing unit according to Embodiment 3 of the present invention.

FIG. 9 is a sectional view showing a fourth embodiment of the present invention.

FIG. 10 is a sectional view showing a roller bearing unit according to a fourth embodiment of the present invention.

FIG. 11 is a side view showing a roller bearing unit according to Embodiment 4 of the present invention.

FIG. 12 is a sectional view showing a conventional zoom lens barrel for an infrared detection device.

FIG. 13 is an external view showing a fixed frame and a cam ring of a conventional zoom lens barrel for an infrared detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st movable lens group 2 2nd movable lens group 3 1st movable frame 4 2nd movable frame 5 1st cam pin 6 2nd cam pin 7 Fixed frame 8 Screw 9 Main body 10 1st groove 11 Second groove 12 Inner cylinder of fixed frame 7 13 Outer cylinder of first movable frame 3 14 Outer cylinder of second movable frame 4 15 Cam ring 16 Gear 17 Motor 18 First cam groove 19 Second cam groove 20 Mount 21 Screw 22 Roller bearing unit 23 Roller bearing 24 Eccentric pin 25 Bracket 26 Nut 27 Screw 28 Retaining ring 29 Guide shaft 30 Guide hole 31 Coil spring 32 First taper plate 33 Second taper plate 34 Screw 35 Adjustment screw 36 Screw Shaft 37 Floating nut 38 Retaining ring 39 Fixed nut 40 Retaining ring insertion hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-113214 (JP, A) JP-A-4-107405 (JP, A) JP-A-3-158809 (JP, A) 9042 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02B 7/04

Claims (5)

(57) [Claims] 1. A fixed frame fixed to a main body of a lens barrel and having a groove in an optical axis direction , a cam ring having a cam groove and rotating about an axis parallel to the optical axis, and moving in the optical axis direction. Yes
First and second movable frame provided on the ability, the first,
First and second movable lens groups attached to the second movable frame, and attached to the first and second movable frames,
And a cam pin which is inserted into the groove in the optical axis direction of the fixed frame and the groove in the cam ring, and moves along the groove in the optical axis direction of the fixed frame by receiving the rotational force of the cam ring. , A roller bearing disposed between the first and second movable frames and the fixed frame, the roller bearing mounted on the first and second movable frames, and between the roller bearing and the fixed frame. A zoom lens barrel including a roller bearing unit having an adjustment member capable of adjusting the clearance of the zoom lens. 2. The zoom lens mirror according to claim 1, wherein an eccentric pin having an eccentric portion having an eccentric portion with an engagement portion with a roller bearing and a fitting portion with a bracket attached to the first and second movable frames is used. Tube. 3. The zoom lens barrel according to claim 1, wherein a coil spring for pressing said roller bearing against said fixed frame and eliminating a clearance between said roller bearing and said fixed frame is used as an adjusting member. 4. A roller bearing engaged with a bracket, and a tapered surface that is in reverse contact with a tapered surface of a second tapered plate, and the tapered surface of the second tapered plate is perpendicular to the optical axis. A first taper plate movably provided in the first direction, and an adjusting screw for moving the first taper plate in a direction perpendicular to the optical axis to move the roller bearing in a radial direction of the inner cylinder of the fixed frame. 2. The zoom lens barrel according to claim 1, wherein a roller bearing unit is constituted by a bracket that engages with the roller bearing, and a fastener that attaches first and second tapered plates to the first and second movable frames. 5. A roller bearing engaged with a bracket, a screw shaft fixed to the bracket and moving in an axial direction, and rotatably provided on the screw shaft.
A floating nut that rotates the screw shaft in the axial direction by rotation to move the roller bearing in the radial direction of the inner cylinder of the fixed frame, and suppresses movement of the floating nut in the axial direction of the screw shaft, and A roller bearing includes a retaining ring engaged with the first and second movable frames so as to be rotatable around an axis, and a fixing nut engaged with the screw shaft and fixing the floating nut. The zoom lens barrel according to claim 1, wherein the zoom lens barrel comprises a unit.