JPH08166529A - Lens barrel - Google Patents

Abstract

PURPOSE: To accurately track a remote object by applying elastic force to a cam ring fitted in a fixed frame and rotating in parallel with an optical axis and a cam ring slidably fitted in the former cam ring and coaxially rotating in the rotating direction. CONSTITUTION: For example, in the lens barrel of an optical system mounted in an airplane and tracking a target; the cam ring 15 is slidably fitted in the fixed frame 7 and rotates centering around an axis in parallel with the optical axis, and the cam ring 22 is slidably fitted in the cam ring 15 and rotates centering around the axis in parallel with the optical axis. A cam pin 5 is engaged in the spiral cam groove 18 of the cam ring 15 and the cam groove 24 of the cam ring 22, so that a movable frame 3 is moved in an optical axis direction as the cam ring 15 is turned. The elastic force is applied to the cam ring 22 in the rotating direction by an elastic member 29 and the cam pin 5 is interposed in contact with the cam grooves 18 and 24. Therefore, a gap between the cam grooves 18 and 29 and the cam pin 5 is made extremely small, the position of a lens is uniquely decided, and an image-formation position is not deviated, then the remote object is accurately tracked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system lens barrel such as an infrared imaging device mounted on an aircraft to search or track a target, and moves the lens group in the optical axis direction for zooming or focus adjustment. It is related to the mechanism.

[0002]

2. Description of the Related Art FIG. 15 is a sectional view showing a conventional zooming or focusing mechanism for a lens barrel. In the figure, 1 is a first movable lens group, and 2 is a second movable lens group. Generally, zooming or focus adjustment is performed by moving the first movable lens group and the second movable lens group in the optical axis direction. 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 5 is a first cam pin, which is the first movable frame 3
The second cam pin 6 is 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 10 and 11 in the optical axis direction, 10 is a first groove into which the first cam pin 5 is inserted, and 11 is a second groove and the second cam pin 6 Are inserted to regulate the first movable lens group 1 and the second rotation direction. Further, 12 is an inner cylinder of the fixed frame 7, and an outer cylinder 1 of the first movable frame 3.
3 and the outer cylinder 14 of the second movable frame 4 are engaged and serve as a guide when movable. 15 is a cam ring, which is a gear 1
Rotation is performed by a motor 17 via 6. However, the optical axis is positioned by the fixed frame 7 and the main body 9. The cam ring 15 has a first cam groove 18 and a second cam groove 18.
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. Reference numeral 20 denotes a mount that engages with the image pickup apparatus and is attached to the main body 9 with a screw 21. FIG. 8 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.

The conventional lens barrel is constructed as described above. Next, the operation will be described. When the motor 17 is rotated by the zooming signal, the rotational force is generated by the gear 16
It is transmitted to the cam ring 15 via and the cam ring 15 rotates. The cam ring 15 has a first cam groove 18 and a second cam groove 18.
There is a cam groove 19 of, and each cam groove also rotates. The first cam pin 5 is inserted into the first cam groove 18,
Since the second cam pin 6 is inserted in the cam groove 19 of, the rotational force is applied to the first cam pin 5 and the second cam pin 6. 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 but receives a moving force in the optical axis direction along each cam groove. This moving force causes the first movable frame 3 and the movable frame 4 to move to a predetermined position with the inner cylinder 12 of the fixed frame 7 as a guide, and constitutes an optical system in a desired zoom magnification or in a focused state.

[0004]

The conventional lens barrel as described above has the following problems. First of all, as a first problem, manufacturing tolerances are required in manufacturing both the cam groove and the cam pin, and it is necessary to provide a large gap to obtain smooth sliding characteristics. . However, since there is a gap between the cam groove and the cam pin, the position of the lens is not uniquely determined, and as a result, the position of the image slightly shifts, which makes it difficult to accurately track a distant object. There was a problem to say. In addition, there is a problem that the portion having such a gap is easily damaged by an external force such as vibration and impact, and the durability is insufficient.

The lens barrel according to the present invention has been made to solve the above problems, and the position of the lens can be reduced by mechanically suppressing and reducing the gap between the cam groove and the cam pin. Is substantially uniquely determined, and the durability against external force such as vibration and shock is to be improved.

As a second problem, in the case where the cam ring of the lens barrel is rotated by transmitting power from the outside with a gear, the cam ring is not removed even if the gap between the cam groove and the cam pin is eliminated as described above. There is backlash between the provided gear part and the gear that transmits power from the outside. Therefore, even when the gear that transmits power from the outside is fixed, the position of the lens cannot be uniquely determined because the cam ring rotates by the amount of backlash between the gears, and as a result, the position of the image slightly shifts. There is a problem that it is difficult to keep track of a distant object accurately.

The lens barrels according to the first and second embodiments of the present invention are designed to solve the above problems.
By eliminating the gap between the cam groove and the cam pin and, at the same time, reducing the backlash between the gear portion provided on the cam ring and the gear that transmits power from the outside, the lens position is made substantially unique. It is intended to be decided.

As a third problem, when the cam ring of the lens barrel is rotated by transmitting power from the outside by a gear, the gap between the cam groove and the cam pin and the cam ring as in the lens according to the second aspect. It is possible to reduce the backlash between the gear portion provided in the gear and the gear that transmits power from the outside. Strictly speaking, however, the gap amount between the cam groove and the cam pin and the backlash amount between the gears, which are caused by manufacturing tolerances in manufacturing, are different, and the amount corresponding to the difference remains as the gap amount. In addition, it is difficult to control the manufacturing tolerance in manufacturing in order to reduce this difference, and it is possible to measure the precision of each part after processing precisely and take measures such as selectively assembling the parts. However, there is a problem that it is disadvantageous in terms of cost.

The lens barrels according to the first and second embodiments of the present invention are designed to solve the above problems.
In the case where the cam ring of the lens barrel is rotated by transmitting power from the outside by a gear, the clearance amount between the cam groove and the cam pin is advantageous in terms of cost regardless of restrictions such as tolerances in machining parts. And a backlash between a gear portion provided on the cam ring and a gear that transmits power from the outside, as a result of eliminating a difference in the amount of backlash between the gear and the gear. It aims to virtually eliminate the rush.

As a fourth problem, in the case of a cam ring having a cam groove with a non-constant lead angle, as is usually seen in a lens having a variable magnification function, depending on the angle of the cam groove, the first cam ring and the movable lens group may have different shapes. There is a problem that the load torque for driving the movable frame fluctuates throughout the movable range. As a result, there is a problem that it is not possible to regulate within a specified torque determined by the output torque of the drive source.

The lens barrels according to the third and fourth embodiments of the present invention have been made to solve the above problems, and have the smallest gap and the output torque of the drive source throughout the movable range of the movable lens group. The torque is regulated within the specified torque determined by to eliminate blurring or blurring of the image and improve durability.

As a fifth problem, when the lens barrel is exposed to an external force such as vibration or impact, the stress applied to the cam pins, the first cam ring, and the cam grooves of the second cam ring is large, so that the cam pins and There is a problem in that the cam groove portions of the first cam ring and the second cam ring are deformed relatively easily and durability is weak.

The lens barrel according to the fifth embodiment of the present invention has been made to solve the above problem, and reduces the stress applied to the cam pins, the first cam ring, and the cam grooves of the second cam ring. The cam pins, the first cam ring, and the cam groove portions of the second cam ring are prevented from being easily deformed, and the durability is improved.

As a sixth problem, as is usually seen in a lens having a variable power function, in a cam ring having a cam groove with a non-constant lead angle, the elastic member is provided between the first cam ring and the second cam ring. In addition to the problem that the load torque for driving the movable frame fluctuates depending on the angle of the cam groove when the elastic force in the rotational direction is applied to, the sensitivity of the position of the movable frame to the rotational angle of the cam ring is High, the error factor is increased at an accelerating rate, and therefore it is necessary to match the allowable error of the control circuit with the level of the position having the largest error factor, which makes control design difficult and is sufficient for the required positioning accuracy of the movable frame. Reliability cannot be obtained. Alternatively, a complicated control circuit is required to increase the reliability, which causes an increase in manufacturing cost.

The lens according to the sixth embodiment of the present invention is made to solve such a problem, and the lens barrel in which the load torque for driving the movable frame does not vary depending on the position of the cam ring in the rotational direction. Is to be configured.

As a seventh problem, as is usually seen in a lens having a variable power function, a mirror in which two or more lens groups are guided to the cam groove and move in the optical axis direction as the cam ring rotates. When the elastic member exerts an elastic force in the rotational direction on the cylinder between the first cam ring and the second cam ring, the moving direction of the lens groups is in the middle of the stroke throughout the entire stroke of the two lens groups. May vary from In such a case, which of the left and right surfaces of the groove of the first movable frame and the second movable frame that regulates the cam pin applied to the movable frame at the position where the moving direction of the lens group changes makes contact with the cam pin. There is a problem that the lens position is not fixed because it is not uniquely determined, and the object at a distant position cannot be accurately tracked because the imaging position is displaced.

The lens barrels according to the seventh and eighth embodiments of the present invention have been made to solve such a problem, and the moving direction of the lens group is the same as that usually found in a lens having a variable power function. An object of the present invention is to provide a lens barrel that can uniquely determine the position of each lens unit even when changing from the middle of the stroke, and can accurately track a distant object without shifting the imaging position.

[0018]

A lens barrel according to a first embodiment of the present invention is slidably fitted to the fixed frame and rotates about a shaft parallel to an optical axis. A second cam ring that is slidably fitted to the first cam ring and that rotates about an axis parallel to the optical axis is provided, and the second cam ring is fixed to the first and second cam rings, and the first and second cam rings are fixed. The cam ring is provided with an elastic member that applies an elastic force in the rotational direction.

Gear portions are provided at the ends of the first cam ring and the second cam ring, and a rotational force transmitted from the outside is passed through gears meshing with the gear portions of the first and second cam rings. The first cam ring and the second cam ring are rotated about an axis parallel to the optical axis.

Further, by providing an eccentric member for adjusting the rotation center of the gear, the amount of backlash between the gear portion provided on the cam ring and the gear for transmitting power from the outside can be adjusted. is there.

The lens barrel according to the second embodiment of the present invention is provided with a position adjusting mechanism in the rotational direction on at least one of the gear portions.

A lens barrel according to a third embodiment of the present invention is configured such that a wedge plate contacting both the first cam ring and the second cam ring in a rotational direction and a screw engagement with the first or second cam ring. The wedge plate is provided with a screw that functions as a push screw and can adjust the relative position in the rotational direction of the first cam ring and the second cam ring.

A lens barrel according to a fourth embodiment of the present invention includes a screw shaft attached to either the first cam ring or the second cam ring and having a shaft in the rotation direction of the first and second cam rings. Floating attached to either the first cam ring or the second cam ring and screw-engaged with the screw shaft to adjust the relative position of the first cam ring and the second cam ring in the rotational direction. It is equipped with a nut.

A lens barrel according to a fifth embodiment of the present invention is rotatably fixed to the movable frame and has an oval cross section that engages with the cam grooves of the fixed frame, the first cam ring, and the second cam ring. The cylindrical cam pin ring is provided.

The lens barrel according to the sixth embodiment of the present invention has a spiral cam groove having a constant lead angle, is slidably fitted in the fixed frame, and rotates about an axis parallel to the optical axis. A second cam ring having a spiral cam groove with a constant lead angle, slidably fitted to the first cam ring, and rotating about an axis parallel to the optical axis. A cam ring is provided.

The lens barrel according to the seventh embodiment of the present invention is slidably fitted to the fixed frame and is slidably mounted on the first cam ring which rotates about an axis parallel to the optical axis. A second cam ring that is movably fitted and that rotates about an axis parallel to the optical axis is provided, and is fixed to the first and second cam rings, and the first and second cam rings are arranged in the optical axis direction. An elastic member that gives an elastic force to is provided.

The lens barrel according to the eighth embodiment of the present invention is a lens barrel having at least two or more movable frames, slidably fitted to the fixed frame and rotated about an axis parallel to the optical axis. A first cam ring, a second and a third cam ring slidably fitted to the first cam ring and rotating about an axis parallel to the optical axis, and the first and second cam rings. An elastic member that is fixed and applies an elastic force to the first and second cam rings in the rotation direction and an elastic member that applies an elastic force to the first and third cam rings in the optical axis direction are provided.

[0028]

In the lens barrel according to the first embodiment of the present invention, the elastic member attracts the first cam ring and the second cam ring in the rotational direction, so that the cam groove of the first cam ring and the second cam ring. Both of the cam grooves of the cam ring come into contact with the cam pin from the opposite direction of the rotation direction, and the gap between the cam groove and the cam pin is eliminated.

Gear portions are provided at the ends of the first cam ring and the second cam ring, and a rotational force transmitted from the outside is passed through a gear meshing with the gear portions of the first and second cam rings. Then, the first cam ring and the second cam ring are rotated about an axis parallel to the optical axis. At this time, the elastic force in the rotational direction by the elastic member acts between the gear portion of the first cam ring end portion and the gear portion of the second cam ring end portion, so that the first and second cam ring end portions It also has the effect of reducing the backlash that occurs between the gear part of the gear and the gear that transmits the rotational force from the outside.

Further, an eccentric member for adjusting the rotation center of the gear is provided. Thereby, the eccentric member can be rotated around the eccentric portion of the eccentric member, and the center-to-center distance between the rotation shafts of the gear portions of the first and second cam rings and the rotation shaft of the gear can be adjusted. . This makes it possible to adjust the amount of backlash between the gear portion of the cam ring and the gear. Due to the above, regardless of restrictions such as tolerances in machining parts,
In addition, it is advantageous in terms of cost to eliminate the difference between the gap amount between the cam groove and the cam pin and the backlash amount between the gears, and as a result, the gap between the cam groove and the cam pin that remains finally and The backlash between the gear portion provided on the cam ring and the gear that transmits power from the outside can be made extremely small.

In the lens barrel according to the second embodiment of the present invention, the position adjustment mechanism in the rotational direction is provided in at least one of the gear portions, so that the cam grooves of the first cam ring and the second cam ring and The backlash amount between the gears can be adjusted to zero at the same time at the position where there is no gap between the engaging cam pins. This eliminates the difference in the gap amount between the cam groove and the cam pin and the backlash amount between the gears, which is advantageous in terms of cost, regardless of restrictions such as tolerances in machining parts, and as a result, It is possible to make extremely small a gap between the cam groove and the cam pin, which finally remains, and a backlash between a gear portion provided on the cam ring and a gear for transmitting power from the outside.

In the lens barrel according to the third embodiment of the present invention, the wedge plate is used to finely adjust the relative position of the first cam ring and the second cam ring in the rotational direction, so that the cam of the first cam ring can be adjusted. The gap between the groove and the cam groove of the second cam ring and the cam pin can be made extremely small.

In the lens barrel according to the fourth embodiment of the present invention, by providing the floating nut and the screw shaft, the relative positions of the first cam ring and the second cam ring in the rotational direction can be finely adjusted. . This makes it possible to make the gap between the cam groove of the first cam ring and the cam groove of the second cam ring and the cam pin extremely small.

In the lens barrel according to the fifth embodiment of the present invention, an oval shape rotatably fixed to the movable frame and engaged with the fixed frame, the first cam ring, and the cam grooves of the second cam ring. It has a ring of cam pins that are cylindrical in cross section.
As a result, the contact area between the cam pin, the first cam ring, and the cam groove of the second cam ring is increased, and the contact area between the cam pin, the first cam ring, and the cam groove of the second cam ring is increased. Such stress can be reduced.

In the lens barrel according to the sixth embodiment of the present invention, the lead angles of the spiral cam grooves of the first cam ring and the second cam ring are made constant, so that the angle of the cam groove causes Since the amount of deformation of the elastic body is constant, the elastic force does not change, and the load torque for driving the movable frame does not change. As a result, sufficient reliability can be obtained for the required positioning accuracy of the movable frame, and a lens barrel that does not require a complicated control circuit can be configured.

In the lens barrel according to the seventh embodiment of the present invention, the elastic member attracts the first cam ring and the second cam ring in the optical axis direction, whereby the cam groove of the first cam ring and the second cam ring are formed. Both of the cam grooves of the cam ring come into contact with the cam pin from opposite directions in the optical axis direction, and the gap between the cam groove and the cam pin is eliminated.

In the lens barrel according to Embodiment 8 of the present invention,
The second cam ring receives a force in the rotation direction by the elastic member, and acts so as to reduce a gap between the second cam ring and the first cam ring. Further, the third cam ring receives a force in the optical axis direction by the elastic member, and acts so as to reduce the gap between the third cam ring and the first cam ring.

[0038]

【Example】

Embodiment 1 FIG. 1 is a diagram showing an example of a lens barrel according to Embodiment 1 of the present invention. In this embodiment, the present invention is applied to a field moving lens movable part having two movable lens groups. In the figure, 1 to 14 and 16, 17, 20, 21
Is the same as the conventional device. 15 is the first cam ring,
22 is a second cam ring, 23 is a third cam ring, 2
Reference numeral 4 is a cam groove of the second cam ring 22, and 25 is a cam groove of the third cam ring 23. 26 is a gear portion of the first cam ring, 27 is a gear portion of the third cam ring, and 28 is an eccentric member.

FIG. 2 is a sectional view of the lens barrel according to the first embodiment of the present invention. In this embodiment, 3 in the circumferential direction.
One cam groove, a cam pin, and an elastic member are provided. In the figures, the same numbers indicate the same parts or portions having the same function. Reference numeral 29 denotes a first elastic member, which applies a contracting force in the rotational direction between the first cam ring 15 and the second cam ring 22.

FIG. 3 is a development view of the cam ring of the lens barrel according to the first embodiment of the present invention. Reference numeral 30 denotes a second elastic member, which includes the first cam ring 15 and the third cam ring 2
3 is given a contracting force in the direction of rotation.

FIGS. 4 (a) and 4 (b) are enlarged views of the eccentric member of the lens barrel according to the first embodiment of the present invention. 31 is a screw for fixing the motor to the eccentric member, 32 is a clamp for fixing the eccentric member to the main body of the lens barrel, 33 is a clamp fixing screw, 34 is an outer circumference of the eccentric member, 35 is an inner circumference of the eccentric member,
Reference numeral 36 denotes an eccentric member arm portion.

Next, the function of each part will be described. The first cam ring 15 has a spiral cam groove, is fitted into the fixed frame 7 slidably in the rotation direction, and rotates about an axis parallel to the optical axis. The second cam ring 22 is the first cam ring 15
It is slidably fitted in the direction of rotation and rotates about an axis parallel to the optical axis. The first cam pin 5 is the first cam ring 15
Cam groove 18 and second cam ring 22 cam groove 2
4, the first movable frame 3 can be moved in the optical axis direction with the rotation of the first cam ring 15. The third cam ring 23 is fitted to the first cam ring 15 so as to be slidable in the rotation direction, and rotates about an axis parallel to the optical axis.
The second cam pin 6 is the cam groove 1 of the first cam ring 15.
9 and the cam groove 25 of the third cam ring 23, the second movable frame 4 can be moved in the optical axis direction with the rotation of the first cam ring 15. Gear portion 26 of the first cam ring and gear portion 27 of the third cam ring
Is engaged with the gear 16, and the rotational driving force by the motor 17 is transmitted through the gear 16, the gear portion 26 of the first cam ring and the gear portion 27 of the third cam ring to the first cam ring 15 and the third cam ring. 23.

As shown in FIGS. 2 and 3, the second cam ring 22 receives an elastic force in the rotational direction by the first elastic member 29. Therefore, the cam pin 5 has a cam groove 18 of the first cam ring and a cam groove 2 of the second cam ring.
4 are in contact with each other so as to be sandwiched from the opposite direction. Similarly, the third cam ring 23 receives elastic force in the rotational direction by the second elastic member 36. Therefore, the cam pin 6 is in contact with the cam groove 19 of the second cam ring and the cam groove 25 of the second cam ring so as to be sandwiched from the opposite direction.

In FIGS. 4A and 4B, 28 is an eccentric member. The motor 17 is fixed to the eccentric member 28 with a screw 31, the eccentric member 28 is rotatably fitted to the main body 9 of the lens barrel, and is further fixed with a clamp 32 and a clamp screw 33. Eccentric member 2
The outer periphery 34 of 8 is eccentric with respect to the inner periphery 35, and by rotating the mounting direction of the eccentric member 28 around the center of the outer periphery 34 of the eccentric member 28 by the arm portion 36 of the eccentric member 28, the position of the rotating shaft of the motor 17 is Adjustable, motor 1
It is possible to adjust the distance between the rotary shaft 7 and the gear portion 26 of the first cam ring and the gear portion 27 of the third cam ring.

Embodiment 2 FIG. 5 is a diagram showing an example of a lens barrel according to Embodiment 2 of the present invention. In the figure, 1 to 26 are the same as in the first embodiment. Three
Reference numeral 7 is a gear wheel associated with the third cam ring 23, and 38 is a fixing screw for the third cam ring 23. It is rotatably fitted to the cam ring 23. The fixing screw 38 of the gear associated with the third cam ring 23 is attached to the gear 3 associated with the third cam ring 23.
9 is fixed to the third cam ring 23. According to the present invention, at the position where there is no gap between the cam groove 19 of the first cam ring 15 and the cam groove 25 of the third cam ring 23 and the cam pin 5 engaging with them, the gear portion 26 of the first cam ring is formed. , The third cam ring 23 at a position where there is no backlash between the gear portion 27 of the third cam ring and the gear 37 associated with the third cam ring 23.
The accompanying gear 37 is fixed to the third cam ring 23.

Embodiment 3 FIGS. 6 and 7 are views showing an example of a lens barrel according to Embodiment 3 of the present invention. In the figure, 1 to 26 are the same as in the first embodiment. 39 is a first wedge plate, 40 is a second wedge plate, 41 and 4
2 is a screw for adjusting the height of the wedge plate. The first wedge plate 39 is sandwiched between the convex portion of the second cam ring 22 and the hole portion of the first cam ring 15, and the second wedge plate 40 is formed between the convex portion of the third cam ring 23 and the convex portion of the third cam ring 23. It is sandwiched between the holes of one cam ring 15 and receives the elastic force of the elastic members 29 and 30, respectively. The screw 41 for adjusting the height of the wedge plate is used for the second cam ring 2.
The first wedge plate 39 is pushed from the upper side by being screwed to the second wedge plate 39. Further, 42 is screwed to the third cam ring 23 to push the first wedge plate 40 from above.

Next, the function of each part will be described. Wedge plate 3
By rotating the height adjusting screw 41 of 9, it is possible to adjust the height of the first wedge plate 35 by a pushing screw effect, and as a result,
The position of the second cam ring 22 with respect to the first cam ring 15 in the rotational direction can be adjusted. Similarly, the rotation of the wedge plate height adjusting screw 42 causes the first wedge plate 39 to rotate.
Can be adjusted by the push screw effect, and as a result, the position of the third cam ring 23 with respect to the first cam ring 15 in the rotational direction can be adjusted.

Embodiment 4 FIGS. 8 and 9 are views showing an example of a lens barrel according to Embodiment 4 of the present invention. In the figure, 1 to 26 are the same as in the first embodiment. 43 is a first screw shaft, 44 is a second screw shaft, 45 and 46 are floating nuts, 47 and 48 are plate portions of second and third cam rings, and 49 and 5.
Reference numeral 0 is a first and second fixing nut, and 51 and 52 are first and second retaining rings.

Since each of these parts has the same structure and function, only one of them will be described below as an example.
The first screw shaft 43 is fixed to the second cam ring 22, and meshes with the floating nut 45. The retaining ring 51 is engaged with the plate portion of the second cam ring so as not to move in the axial direction. However, rotation around the axis is possible. By tightening the fixing nut 49, a floating nut 45 and a double nut effect are obtained, and the floating nut 45 works as a loosening prevention.

Embodiment 5 FIG. 10 is a diagram showing an example of a lens barrel according to Embodiment 5 of the present invention. In the figure, 1 to 14 and 16 to 21 are exactly the same as in the first embodiment. 53 and 54 are first and second cam followers, 55 and 56 are first and second bushes, 5
Reference numerals 7 and 58 are first and second bush fixing screws. Since each of these parts has the same structure and function, only one of them will be described below as an example.

Since each of these parts has the same structure and function, only one of them will be described below as an example.
FIG. 11 is a detailed view showing one of the pair of lens barrels according to the present invention. In the figure, 4, 7, 15, and 23 are exactly the same as in the first embodiment. The cam follower 54 is composed of an oval cross section and a circular cross section. The oval cross section is slidably fitted in the cam groove 19 of the first cam ring 15 and the cam groove 25 of the third cam ring 23. There is. The portion having a circular cross section is slidably fitted in the guide groove 11 of the cam ring 7. The bush 56 is rotatably fitted to the cam follower 54, and is fixed to the movable frame 4 by a bush fixing screw 58.

With the rotation of the first cam ring 15 and the third cam ring 23, the cam follower 54 moves the second cam groove 19 of the first cam ring 15 and the third cam ring 2 together.
While moving relative to the bush 56 following the cam groove 25 of No. 3, the movable frame 4 is moved in the optical axis direction by moving in the guide groove 11 of the cam ring 7 in the optical axis direction.

Embodiment 6 FIG. 12 is a diagram showing an example of a lens barrel according to Embodiment 6 of the present invention, in which the fixed frame 7 and the first cam ring 1 in Embodiment 1 are shown.
FIG. 5 is a developed view of a part of the second cam ring 22, the third cam ring 22, and the third cam ring 23. In the figure, 5, 6, 7, 1
0, 11, 15, 28 and 29 are the same as those shown in the first embodiment. Here, the first cam groove 18 and the second cam groove 19 of the first cam ring 15, the second cam ring cam groove 24, and the third cam ring cam groove 25.
Has a constant lead angle. Therefore, the torque transmitted from the rotary drive source always acts as a thrust on the cam pin at a constant rate, and the torque for driving the lens is also always constant.

Embodiment 7 FIG. 13 is a view showing an example of a lens barrel according to Embodiment 7 of the present invention, in which one of the fixed frame 7, the first cam ring 15, the second cam ring 22, and the third cam ring 23 is shown. This is an expanded version of the section. In the figure, 5, 6, 7, 10, 11, 15,
28 and 29 are the same as those shown in the first embodiment. Reference numeral 59 is a first elastic member, and 60 is a second elastic member.

The second cam ring 22 receives a contracting force in the optical axis direction by the first elastic member 59. Therefore, the cam pin 5 is in contact with the cam groove 18 of the first cam ring and the cam groove 24 of the second cam ring so as to be sandwiched from the opposite direction. Similarly, the third cam ring 23 receives elastic force in the optical axis direction by the second elastic member 60. Therefore, the cam pin 6 is in contact with the cam groove 19 of the second cam ring and the cam groove 25 of the second cam ring so as to be sandwiched from the opposite direction.

As described above, in the first to seventh embodiments of the present invention, the case where the present invention is applied to the lens movable portion for switching the field of view having two movable lens groups has been described or illustrated. In the case of only one group, a series of parts relating to the third cam barrel is not necessary, and the lens barrel can be constructed with the same mechanism in other cases. Therefore, the mechanism according to the present invention can be applied regardless of the number of the movable lens groups or the number of the movable lens groups as in the case of the first embodiment.

Embodiment 8 FIG. 14 is a view showing an example of a lens barrel according to Embodiment 8 of the present invention, in which one of a fixed frame 7, a first cam ring 15, a second cam ring 22 and a third cam ring 23 is shown. This is an expanded version of the section. In the figure, 5, 6, 7, 10, 11, 15,
28 and 29 are the same as those shown in the first embodiment. Reference numeral 61 is a first elastic member, and 62 is a second elastic member.

The second cam ring 22 receives a contracting force in the rotational direction by the first elastic member 61. Therefore, the cam pin 5 is in contact with the cam groove 18 of the first cam ring and the cam groove 24 of the second cam ring so as to be sandwiched from the opposite direction. Similarly, the third cam ring 23 receives elastic force in the optical axis direction by the second elastic member 62. Therefore, the cam pin 6 is in contact with the cam groove 19 of the first cam ring and the cam groove 25 of the second cam ring so as to be sandwiched from the opposite direction.

[0059]

The lens barrel according to the first embodiment of the present invention is slidably fitted to the fixed frame and rotates about an axis parallel to the optical axis, and the first cam ring. A second cam ring that is slidably fitted to the optical axis and rotates about an axis parallel to the optical axis, and is fixed to the first and second cam rings to rotate the first and second cam rings. By having an elastic member that gives elastic force in the direction,
The gap between the cam groove and the cam pin is extremely small, which allows the position of the lens to be determined substantially uniquely. As a result, the position of the image does not shift, and distant objects can continue to be tracked accurately.

Further, gear portions are provided at the ends of the first cam ring and the second cam ring, and gears for transmitting a rotational force from the outside are meshed with the gear portions of the first and second cam rings to form an optical axis. The first cam ring and the second cam ring are rotated about an axis parallel to. At this time, the elastic force in the rotational direction by the elastic member acts between the gear portion of the first cam ring end portion and the gear portion of the second cam ring end portion, so that the first and second cam ring end portions It also has the effect of reducing the backlash that occurs between the gear part of the gear and the gear that transmits the rotational force from the outside. As a result, the position of the lens can be determined substantially uniquely, and as a result, the position of the image does not shift and an object at a distance can be accurately tracked.

Further, by providing an eccentric member comprising a shaft portion rotatably fitted to the gear and a flange portion eccentric to the shaft portion, the eccentric member is rotated about the collar portion. The center distance between the rotating shafts of the gear parts of the first and second cam rings and the rotating shaft of the gear can be adjusted, and as a result, the back gap between the gear parts of the cam ring and the gear can be adjusted. It is possible to adjust the amount of lash. Therefore, at the position where there is no gap between the cam grooves of the first cam ring and the second cam ring and the cam pins engaged with these,
The center-to-center distance can be adjusted so that the amount of backlash between the gears is also zero at the same time, and as a result, the gap between the cam groove and the cam pin that remains finally and the gear portion provided on the cam ring The backlash between the gear that transmits power from the outside and the gear that transmits power from the outside can be made extremely small, and as a result, the position of the image does not shift and distant objects can continue to be accurately tracked.

In the lens barrel according to the second embodiment of the present invention, since the position adjusting mechanism in the rotational direction is provided on at least one of the gear parts, the cam grooves of the first cam ring and the second cam ring, and these The backlash amount between the gears can be adjusted to zero at the same time at the position where there is no gap between the cam pins that engage with. This eliminates the difference in the gap amount between the cam groove and the cam pin and the backlash amount between the gears, which is advantageous in terms of cost, regardless of restrictions such as tolerances in machining parts, and as a result, It is possible to make extremely small a gap between the cam groove and the cam pin, which finally remains, and a backlash between a gear portion provided on the cam ring and a gear for transmitting power from the outside.

The lens barrel according to the third embodiment of the present invention is slidably fitted to the fixed frame and slides on the first cam ring which rotates about an axis parallel to the optical axis and the first cam ring. A second cam ring that is movably fitted and that rotates about an axis parallel to the optical axis is provided, and a wedge plate that can adjust the relative position of the first and second cam rings in the rotational direction is provided. By doing so, the gap between the cam groove and the cam pin can be made extremely small, whereby the position of the lens can be substantially uniquely determined. As a result, the position of the image does not shift, and distant objects can continue to be tracked accurately.

The lens barrel according to the fourth embodiment of the present invention is slidably fitted to the fixed frame and is slidably mounted on the first cam ring which rotates about an axis parallel to the optical axis. A floating nut and a screw that are movably fitted and that are provided with a second cam ring that rotates about an axis parallel to the optical axis and that can adjust the relative position of the first and second cam rings in the rotational direction. By having a shaft,
The gap between the cam groove and the cam pin is extremely small, which allows the position of the lens to be determined substantially uniquely. As a result, the position of the image does not shift, and distant objects can continue to be tracked accurately.

The lens barrel according to the fifth embodiment of the present invention is rotatably fixed to the movable frame, and has an oval cross section that engages with the cam grooves of the fixed frame, the first cam ring, and the second cam ring. By providing the cylindrical cam pin ring, the contact area between the cam pin and the cam grooves of the first cam ring and the second cam ring is increased. Therefore, the stress applied between the cam pin, the first cam ring, and the cam groove of the second cam ring becomes small, and the cam pin, the ring, the first cam ring, and the cam groove portion of the second cam ring. Can be prevented from being easily deformed, and as a result, it is possible to improve the durability under a use environment in which it is subjected to vibrations and shocks.

In the lens according to the sixth embodiment of the present invention, the lead angle of the spiral cam groove of the first cam ring and the second cam ring is made constant, so that the elastic body is adjusted according to the angle of the cam groove. Since the amount of deformation is constant, the elastic force does not change, and the load torque for driving the movable frame does not change. As a result, sufficient reliability can be obtained for the required positioning accuracy of the movable frame, and a lens barrel that does not require a complicated control circuit can be configured.

The lens barrel according to the seventh embodiment of the present invention is slidably fitted to the fixed frame and slidably attached to the first cam ring which rotates about an axis parallel to the optical axis and the first cam ring. A second cam ring that is movably fitted and that rotates about an axis parallel to the optical axis is provided, and is fixed to the first and second cam rings, and the first and second cam rings are arranged in the optical axis direction. By including an elastic member that gives an elastic force to the, the gap between the cam groove and the cam pin is made extremely small,
This allows the position of the lens to be determined substantially uniquely. As a result, the position of the image does not shift, and distant objects can continue to be tracked accurately.

The lens barrel according to Embodiment 8 of the present invention includes a first cam ring which is slidably fitted to the fixed frame and which rotates about an axis parallel to the optical axis, and the first cam ring. Second and third cam rings that are slidably fitted and that rotate about an axis parallel to the optical axis, and that are fixed to the first and second cam rings and that rotate the first and second cam rings The second cam ring receives a force in the rotational direction by the elastic member by having an elastic member that applies an elastic force in the optical axis direction and an elastic member that applies an elastic force in the optical axis direction to the first and third cam rings. By reducing the gap between the first cam ring and the first cam ring, and by reducing the gap between the third cam ring and the first cam ring in the optical axis direction by the elastic member. Uniquely determines the position of each lens group It can not shift imaging position, also the vibration can be improved durability against an external force such as an impact.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a cross section of Embodiment 1 of the present invention.

FIG. 3 is a diagram showing a developed view of the cam ring according to the first embodiment of the present invention.

FIG. 4 is a diagram showing details of an eccentric portion in Embodiment 1 of the present invention.

FIG. 5 is a diagram showing details of a gear portion in Embodiment 2 of the present invention.

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

FIG. 7 is a diagram showing details of a wedge plate in Embodiment 3 of the present invention.

FIG. 8 is a diagram showing Embodiment 4 of the present invention.

FIG. 9 is a diagram showing details of a floating nut in Embodiment 4 of the present invention.

FIG. 10 is a diagram showing Embodiment 5 of the present invention.

FIG. 11 is a diagram showing details of a cam follower in Embodiment 5 of the present invention.

FIG. 12 is a diagram showing an example of a lens barrel in Embodiment 6 of the present invention.

FIG. 13 is a development view of the cam ring according to the seventh embodiment of the present invention.

FIG. 14 is a development view of a cam ring according to an eighth embodiment of the present invention.

FIG. 15 is a view showing a conventional lens barrel.

[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 13 Outer cylinder of movable frame 3 Outer cylinder of movable frame 4 15 First cam ring 16 Gear 17 Motor 18 First cam groove 19 Second cam groove 20 Mount 21 Screw 22 Second Cam ring 23 Third cam ring 24 Cam groove of second cam ring 25 Cam groove of third cam ring 26 Gear portion of first cam ring 27 Third gear portion of cam ring 28 Eccentric member 29 First elastic member 30 Second Elastic member 31 Motor fixing screw 32 Clamp 33 Clamp fixing screw 34 Eccentric member outer circumference 35 Eccentric member inner circumference 36 Eccentric member arm portion 37 Third tooth associated with cam ring Car 38 Fixing screw 39 First wedge plate 40 Second wedge plate 41 First wedge plate height adjusting screw 42 Second wedge plate height adjusting screw 43 First screw shaft 44 Second Screw shaft 45 First floating nut 46 Second floating nut 47 Plate portion of second cam ring 48 Plate portion of third cam ring 49 First fixing nut 50 Second fixing nut 51 First snap ring 52 Second Second snap ring 53 First cam follower 54 Second cam follower 55 First bush 56 Second bush 57 First bush fixing screw 58 Second bush fixing screw 59 First elastic member 60 Second elastic member 61 First elastic member 62 Second elastic member

Claims (10)

[Claims] 1. A lens barrel having a field switching or focus adjusting function, wherein the lens barrel is fixed to the main body of the lens barrel and has a straight or spiral cam groove in the optical axis direction, and a spiral frame. A first cam ring, which has a cam groove and is slidably fitted to the fixed frame in a rotation direction around the optical axis direction, and a spiral cam groove, are provided in the first cam ring. A second cam ring that slidably fits in a rotation direction around the axis, a lens movable frame that houses one or more lenses inside, and can move in the optical axis direction, and the lens movable A pin fixed to the frame and slidably engaged with the cam grooves of the fixed frame, the first cam ring and the second cam ring; and fixed to the first and second cam rings, the first and second The cam ring of this model has an elastic member that applies elastic force in the rotational direction. A lens barrel characterized by having a mechanism for moving parts. 2. The first cam ring and the second cam ring have gear portions respectively, and gears meshing with the gear portions of the first and second cam rings are provided. Lens barrel. 3. The lens barrel according to claim 2, further comprising a gear that meshes with gear portions of the first and second cam rings, and an eccentric member that adjusts a rotation center of the gear. 4. The lens according to claim 2, wherein each of the first cam ring and the second cam ring has a gear portion, and at least one of the gear portions has a position adjusting mechanism in a rotational direction. Lens barrel. 5. A wedge plate rotationally contacting both the first cam ring and the second cam ring, and a screw engagement with the first or second cam ring, which acts as a push screw on the wedge plate, The lens barrel according to claim 1, further comprising a screw capable of adjusting a relative position of the first cam ring and the second cam ring in a rotational direction. 6. A screw shaft attached to either the first cam ring or the second cam ring and having a shaft in the rotation direction of the first and second cam rings, the first cam ring and the second cam ring. A floating nut attached to any one of the cam rings, which is screw-engaged with the screw shaft and is capable of adjusting a relative position of the first cam ring and the second cam ring in a rotational direction. Item 1. The lens barrel according to item 1. 7. A tubular cam follower having an oval cross section, which is rotatably fixed to the movable frame and engages with the cam grooves of the fixed frame, the first cam ring, and the second cam ring. The lens barrel according to claim 1, wherein the lens barrel is a lens barrel. 8. A spiral cam groove having a constant lead angle,
A first cam ring slidably fitted to the fixed frame and slidably fitted in a rotation direction around the optical axis direction; and a spiral cam groove having a constant lead angle, 2. The lens barrel according to claim 1, further comprising a second cam ring slidably fitted in the first cam ring in a rotation direction about the optical axis. 9. A lens barrel having a field switching or focus adjusting function, wherein the lens barrel is fixed to the main body of the lens barrel and has a straight or spiral cam groove in the optical axis direction, and a spiral frame. A first cam ring, which has a cam groove and is slidably fitted to the fixed frame in a rotation direction around the optical axis direction, and a spiral cam groove, are provided in the first cam ring. A second cam ring that slidably fits in a rotation direction around the axis, a lens movable frame that houses one or more lenses inside, and can move in the optical axis direction, and the lens movable A pin fixed to the frame and slidably engaged with the cam grooves of the fixed frame, the first cam ring and the second cam ring; and fixed to the first and second cam rings, the first and second The cam ring of this model has an elastic member that applies elastic force in the optical axis direction. A lens barrel characterized by having a mechanism for moving parts. 10. A lens barrel having at least two or more lens movable frames having a field-of-view switching or focus adjusting function, which is fixed to a main body of the lens barrel and has a linear or spiral cam groove in the optical axis direction. A fixed cam frame having a spiral cam groove, a first cam ring slidably fitted in the fixed frame in a rotational direction around the optical axis direction, and a spiral cam groove. A second cam ring slidably fitted to the first cam ring in a rotation direction about the optical axis direction,
A lens movable frame that houses one or more lenses inside and can move in the optical axis direction, and a cam groove of the fixed frame, the first cam ring, and the second cam ring that is fixed to the lens movable frame. A pin slidably engaged with the elastic member, and an elastic member fixed to the first and second cam rings to apply an elastic force to the first and second cam rings in a rotational direction.
A lens barrel, comprising a mechanism of a lens movable portion fixed to the first and third cam rings and having an elastic member that applies an elastic force to the first and third cam rings in the optical axis direction.