JPH06167645A - Zoom lens barrel - Google Patents

Abstract

(57) [Summary] [Object] To obtain a zoom lens barrel for an infrared detection device, in which the accuracy of the radial position of the lens of the movable part is improved. [Structure] A roller bearing unit 22 is arranged on the first movable frame 3 and the second movable frame 4, and is engaged with the inner cylinder 12 of the fixed frame 7 by a roller bearing 23 of the roller bearing unit 22. The sliding movement of the movable frame 3 and the second movable frame 4 is made to be a rolling slide to reduce the clearance, and the roller bearing 23 is attached to the eccentric pin 2.
It became possible to adjust the clearance when assembling with 4.

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, for example, an infrared detector which detects infrared rays and generates a signal, and which is adapted to change the shortest shooting distance in association with zooming.

[0002]

2. Description of the Related Art FIG. 12 is a sectional view showing a conventional zoom lens barrel for an infrared detection 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 conven- tor and constitutes a focus lens group. Reference numeral 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 is a first cam pin attached to the first movable frame 3, and 6 is a second cam pin attached to the second movable frame 4. A fixing frame 7 is fixed to the main body 9 with screws 8. The fixed frame 7 has two grooves in the optical axis direction, and 10 is a first groove in which the first cam pin 5 is inserted.
Reference numeral 1 denotes a second groove into which the second cam pin 6 is inserted, and the first movable lens group 1 and the second movable lens group 2
The rotation direction of 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 and serves as a guide during movement. A cam ring 15 is a motor 1 via a gear 16.
Rotating motion is performed by 7. 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, the first cam pin 5 is inserted in the first cam groove 18, and the second cam pin 6 is inserted in the second cam groove 19. Has been inserted. FIG. 13 is an external view of the fixed frame 7 and the cam ring 15, and 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 groove in the cam ring 15 are shown.
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 with a screw 18.

A conventional zoom lens barrel for an infrared detection device is constructed as described above. Next, the operation will be described. When the motor 17 rotates according to the 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 the respective cam grooves also rotate. Since the first cam pin 5 is inserted in the first cam groove 18 and the second cam pin 6 is inserted in the second cam groove 19, the first cam pin 5 and the second cam pin 6 are inserted. Rotational force is applied. However, since the first cam pin 5 is also inserted in the first groove 10 of the fixed frame 7 and the second cam pin 6 is also inserted in the second groove 11 of the fixed frame 7, rotation is restricted. It does not rotate and receives a moving force along the respective cam grooves in the optical axis direction. This moving force causes the first movable frame 3 and the second movable frame 4 to move to a predetermined position with the inner cylinder 12 of the fixed frame 7 as a guide, thereby forming an optical system on the telephoto side and the wide-angle side.

[0004]

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

However, in the conventional zoom lens barrel for an infrared detection device, the first movable lens group and the second movable lens group 2 are moved by using the inner cylinder 12 of the fixed frame 7 as a guide. 3 and the second movable frame 4 move, the positional accuracy of the lens in the radial direction is the dimensional accuracy of the inner cylinder 12 of the fixed frame 7 and the outer cylinder 1 of the first movable frame 3.
3 and the dimensional accuracy of the outer cylinder 14 of the second movable frame 4 determine the clearance. Since this sliding portion is a sliding slide, if the clearance is made small, the frictional force becomes large and it becomes impossible to slide. Therefore, a large clearance is inevitably required 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 and the second cylinder
The outer cylinder 14 of the movable frame 4 could not be adjusted in the clearance only by assembling it after processing, and there was a problem that the clearance varied greatly.

The present invention has been made to solve such a problem, and by changing the sliding method by the conventional sliding, the inner cylinder 12 of the fixed frame 7 and the outer cylinder 13 of the first movable frame 3 and An object of the present invention is to obtain a zoom lens barrel for an infrared detection device in which the clearance of the outer cylinder 14 of the second movable frame 4 is made small and the positional accuracy of the lens in the radial direction is improved.

[0007]

In the zoom lens barrel for an infrared detecting device according to the present invention, a roller bearing is arranged in the sliding portion, and the clearance is reduced by changing from sliding sliding to rolling sliding. The position accuracy in the radial direction is improved.

According to the present invention, the position of the roller bearing can be adjusted by the eccentric pin at the time of assembly, and the variation in the clearance can be suppressed regardless of the processing accuracy.

Further, in the zoom lens barrel for an infrared detection device according to the present invention, a roller bearing is arranged in the sliding portion to change from sliding sliding to rolling sliding to reduce the frictional force, and the roller bearing is made of a coil spring. By pressing it against the inner cylinder of the fixed frame with force, the clearance is eliminated 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 the taper plate or the floating nut and the screw shaft when assembled.

[0011]

In the present invention, the first movable frame 3 and the second movable frame 3
Since the roller bearing is attached to the movable frame 4 and is engaged with the inner cylinder 12 of the fixed frame 7 by the roller bearing, sliding sliding is changed to rolling sliding, and even if the clearance is reduced, the frictional force does not increase. It is possible to slide, and as a result, it is possible to obtain a zoom lens barrel for an infrared detection device in which the positional accuracy of the lens in the radial direction is improved.

In the present invention, the roller bearings are attached to the first movable frame 3 and the second movable frame 4 via the coil springs, and the inner cylinder 12 of the fixed frame 7 is engaged with the roller bearings so that the coil springs It is possible to obtain a zoom lens barrel for an infrared detection device in which the clearance of the sliding portion is eliminated by force and, as a result, the positional accuracy of the lens in the engagement direction is improved.

[0013]

【Example】

Example 1. FIG. 1 is a sectional view showing an embodiment of the present invention. In the figure, 1 to 21 are the same as the conventional device. Two
Reference numeral 2a denotes a roller bearing unit, and three or more sets are attached to the outer circumferences 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 drawing, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and the spherical portion of 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 optical axis pope of the lens from sagging. 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, in the eccentric pin 24, the engaging portion of the roller bearing 23 and the fitting portion of the bracket 25 are eccentric. Reference numeral 26 denotes a nut, which fixes the eccentric pin 24 to the bracket 25. 27 is a screw that attaches 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 constructed as described above, the inner barrel 12 of the fixed frame 7 is engaged with the spherical portion on the outer periphery of the roller bearing 23, and it 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, so the bracket 2
The engagement 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 adjusted nut 26 after adjustment, the clearance between the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 does not change thereafter. In this way, the clearance can be controlled to be constant regardless of the machining accuracy of the parts, and the variation in the clearance can be suppressed.

Example 2. Second Embodiment FIG. 4 is a sectional view showing a second embodiment of the present invention. In the figure, 1 to 21 are the same as the conventional device. Reference numeral 22b denotes a roller bearing unit, and three or more sets are attached to the outer circumferences of the first movable frame 3 and the second movable frame 4 at equal positions.

FIG. 5 shows a roller bearing unit 22b of the present invention.
FIG. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion of 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 sagging in the optical axis direction. Reference numeral 24 is a pin that engages the roller bearing 23 with the bracket 25. Two
A retaining ring 8 fixes the pin 24 to the bracket 25. 29 is a guide shaft, and the bracket 25
Supporting Reference numeral 30 denotes a guide hole, which engages with the guide shaft 29 and determines the position of the roller bearing unit 22b. 31 is a coil spring, and the force of the coil spring 31 causes the guide shaft 29 and the bracket 2 to
The roller bearing 23 is pressed against the inner cylinder 12 of the fixed frame 7 via 5.

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

The roller bearing 23 is a coil spring 31.
The force is applied to the inner cylinder 12 of the fixed frame 7 to eliminate the clearance of the sliding portion, so that the clearance can always be eliminated even if the machining accuracy of the inner cylinder 12 of the fixed frame 7 is poor. . Thus, the clearance can be eliminated regardless of the processing accuracy of the parts, and the positional accuracy of the lens in the radial direction can be improved.

Example 3. FIG. 6 is a sectional view showing a third embodiment of the present invention. In the figure, 1 to 21 are the same as the conventional device. Reference numeral 22c is a roller bearing unit, and three or more sets are attached to the outer circumferences of the first movable frame 3 and the second movable frame 4 at equal positions.

FIG. 7 shows a roller bearing unit 22c of the present invention.
FIG. In the figure, reference numeral 23 denotes a roller bearing having a spherical outer periphery, and a spherical portion of 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 sagging in the optical axis direction. Reference numeral 24 is a pin, and the roller bearing 23 is engaged with the bracket 25.
Reference numeral 28 denotes a retaining ring that 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 taper angle of the second taper plate 33 are the same,
The respective tapered surfaces are in contact with each other in opposite directions. Reference numeral 34 denotes a screw, which attaches the bracket 25, the first taper plate 32, and the second taper plate 33 to the first movable frame 3 and the second movable frame 4. Reference numeral 35 denotes an adjusting screw that pushes the outer peripheral portion of the first taper plate 32 in the direction perpendicular to the optical axis.

FIG. 8 shows a roller bearing unit 22c of the present invention.
FIG. As shown in FIGS. 7 and 8, the bracket 25 and the second taper plate 33 have four surfaces on the outer periphery of the first part.
The movable frame 3 and the second movable frame 4 are engaged with each other 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, and is prevented from shifting in the optical axis direction. An outer peripheral portion of the first taper plate 32 in a direction perpendicular to the optical axis has a clearance with respect to the first movable frame 3 and the second movable frame 4 and is movable.

In the infrared lens zoom lens barrel constructed as described above, the inner barrel 12 of the fixed frame 7 is engaged with the spherical portion on the outer periphery of the roller bearing 23, and is rolled and slid when the lens is moved. 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.

During assembly, when the adjusting screw 35 pushes the outer peripheral portion of the first taper plate 32 in the direction perpendicular to the optical axis, the first taper plate 32 moves on the taper surface of the second taper plate 33. And move in the direction at a right angle. When the first taper plate 32 moves in the 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 screw 34, the clearance between the roller bearing 23 and the inner cylinder 12 of the fixed frame 7 does not change thereafter. In this way, the clearance can be controlled to be constant regardless of the machining accuracy of the parts, and the variation in the clearance can be suppressed.

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

FIG. 10 shows a 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 of 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 sagging in the optical axis direction. Reference numeral 24 is a pin that engages the roller bearing 23 with the bracket 25. Two
A retaining ring 8 fixes the pin 24 to the bracket 25. A screw shaft 36 is fixed to the bracket 25. A floating nut 37 is meshed 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. A fixed nut 39 has a double nut effect with the floating nut 37 by tightening the fixed nut, and acts as a loosening stopper for the floating nut 37. Numeral 40 is a retaining ring insertion hole, which is provided in the first movable frame 3 and the second movable frame 4, and is inserted by using this hole 40 when the retaining ring 38 is assembled in the floating nut 37.

FIG. 11 shows a roller bearing unit 22 of 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 be displaced in the optical axis direction and the direction orthogonal to the optical axis. Has become.

In the infrared lens zoom lens barrel constructed as described above, the inner barrel 12 of the fixed frame 7 is engaged with the spherical portion on the outer periphery of the roller bearing 23, and is rolled and slid when the lens is moved. 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.

During assembly, the floating nut 37
When you rotate, the floating nut 37
Since it does not move in the axial direction, 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, 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. The clearance 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 have an effect so that the floating nut 37 does not loosen, and thereafter the roller bearing 23 and the inner cylinder 12 of the fixed frame 7
The clearance does not change. In this way, the clearance can be controlled to be constant regardless of the machining accuracy of the parts, and the variation in the clearance can be suppressed.

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

[0033]

According to the present invention, the roller bearing 23 fixes the fixed frame 7
By engaging with the inner cylinder 12 and making the roller slide when the lens moves, the clearance of the sliding portion can be reduced and the positional accuracy of the lens in the radial direction can be improved. Also, since the roller bearing 23 can be adjusted in position by an adjusting member during assembly,
Regardless of the processing accuracy of the parts, the clearance can be controlled to be constant and the variations in the clearance can be suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment 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 an eccentric pin of the present invention.

FIG. 4 is a sectional view showing Embodiment 2 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 Embodiment 3 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 a third embodiment of the present invention.

FIG. 9 is a sectional view showing Embodiment 4 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 a fourth embodiment 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]

 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 Outer cylinder of first movable frame 3 Outer cylinder of second movable frame 4 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 Fixing nut 40 Retaining ring insertion hole

Claims (5)

[Claims] 1. A fixing 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 first and second cam rings. First and second movable lens groups provided in the movable frame in such a manner as to be movable in the optical axis direction, and grooves and cam rings in the optical axis direction of the fixed frame which are attached to the first and second movable frames. In a groove of the zoom ring, and a cam pin that moves along the groove of the fixed frame in the optical axis direction by receiving the rotational force of the cam ring. A roller bearing arranged between the fixed frames, and a roller bearing having the roller bearings mounted on the first and second movable frames and capable of adjusting a clearance between the roller bearings and the fixed frame. Zoom lens with unit Lens barrel. 2. The zoom lens mirror according to claim 1, wherein an eccentric pin having an eccentricity in an engaging portion with a roller bearing and an engaging portion with a bracket attached to the first and second movable frames is eccentric. Cylinder. 3. The zoom lens barrel according to claim 1, wherein a coil spring for pressing the roller bearing against the fixed frame to eliminate a clearance between the roller bearing and the fixed frame is used as an adjusting member. 4. A roller bearing engaged with a bracket, and a taper surface contacting the taper surface of the second taper plate in the opposite direction, and the taper surface of the second taper plate is perpendicular to the optical axis. A first taper plate movably provided in a 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 the radial direction of the inner cylinder of the fixed frame. 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 the first and second taper plates to the first and second movable frames. 5. The 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 moves 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 a movement of the floating nut in the axial direction of the floating nut, and Roller bearing with a retaining ring engaged with the first and second movable frames so as to be rotatable about an axis and a fixed nut for engaging with the screw shaft and fixing the floating nut The zoom lens barrel according to claim 1, which constitutes a unit.