JPH071409U - Lens drive - Google Patents

Abstract

(57) [Summary] [Purpose] To enable a drive system unit and a driven system unit to be easily connected in such a manner that the rotation of the nut is reliably prevented. [Structure] A nut 2 screwed into the lead screw 1 has a quadrangular outer shape, and the nut 2 is arranged close to a plate-shaped rubber damper 8 so that the nut accompanying the rotation of the lead screw 1 is rotated. The rotation of the lead screw 1 is prevented, and the rotational movement of the lead screw 1 is converted into the linear movement of the nut 2. Since the nut receiving pins 7a and 7b formed integrally with the lens frame 3 are pressed against the nut 2 by the action of the coil spring 6, the lens frame 3 has the nut 2
Moves in conjunction with.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lens driving device for driving a focusing lens, a zoom lens, etc. in a video camera, a still camera or the like.

[0002]

[Prior art]

 As a lens driving mechanism for video and still cameras, a screw-type lens driving device that moves a lens by screwing a nut to which a lens frame is connected to a lead screw and converting the rotational movement of the lead screw into a straight movement of the nut. However, in this lens driving device, the straight movement of the nut is realized by blocking the rotation of the nut that is screw-fitted. As this rotation blocking method, the lens disclosed in Japanese Patent Laid-Open No. 2-266311 is used. Drives are known.

In this lens driving device, as shown in FIG. 6, a nut 17 is screw-fitted to a lead screw 16 a connected to a motor shaft 16. Further, the nut receiver 22 formed integrally with the lens frame 12 is biased by the spring 19 in the direction of the arrow in FIG. 6 to press the nut 17. When the motor shaft 16 is rotated, the nut 17 also tries to rotate following the lead screw 16a due to the frictional force between the lead screw 16a and the nut 17, but the protrusion 17a formed on the nut 17 becomes the damper rubber 18. Since the nut 17 is inserted into the formed hole, the nut 17 is prevented from rotating and moves linearly while being screwed into the lead screw 16a. At this time, the driven lens frame 12 moves linearly in conjunction with the nut 17, and this lens driving device includes a drive system unit including the motor 14, the lead screw 16a, and the nut 17, and a driven lens frame 12 including a driven system. It is possible to make a system unit separately and assemble and adjust both at the final stage, and this has the advantage that the assembly and adjustment work becomes easier.

[0004]

[Problems to be Solved by the Invention] However, it is difficult to confirm whether or not the protrusion 17a of the nut 17 is inserted into the groove of the damper rubber 18 at the time of assembly. If the damper rubber 18 is mounted on the damper rubber 18 without entering, there is a problem that a large radial force is applied to the motor shaft 16 to cause malfunction.

An object of the present invention is to make it possible to easily connect a drive system unit and a driven system unit in a manner in which rotation of a nut is reliably prevented.

[0006]

[Means for Solving the Problems]

 A linear portion is formed on at least a part of the outer periphery of the female screw member in the screw type lens driving device and at least a portion of the lens frame body that supports the lens, and the linear portion of the lens frame body and the straight line of the female screw member are formed. The positional relationship is such that the strip-shaped portions face each other.

[0007]

[Action]

 When assembling the drive system unit including the female screw member to the lens frame body that is a part of the driven system unit, make sure that the linear portion of the female screw member and the linear portion of the lens frame body face each other. , The drive system unit is simply placed at a predetermined position next to the driven system unit. When the drive system unit is mounted in this way, when the male screw member rotates, the rotation of the female screw member due to the rotation is blocked by the contact between the two linear portions, so that the female screw member is rotated. Moves linearly, and the lens in the lens frame also moves in the optical axis direction in conjunction with the linear motion.

[0008]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings.

1 to 4 show an embodiment of a lens driving device according to the present invention.

This lens drive device includes a drive system unit including a motor M, a lead screw 1 and a nut 2, a lens frame 3, a lens frame support 4, upper and lower two guide pins 5a, a coil spring 6 and two. It is composed of a driven system unit having nut receiving pins 7a and 7b, a rubber damper 8 and the like. Each unit is manufactured separately, and the drive system unit is attached to the driven system unit at the final stage of assembly. .

The lead screw 1 of the drive system unit is threaded and attached to the shaft Ma of the motor M. The outer circumference of the nut 2 is a square (see FIG. 2) and is screwed onto the lead screw 1 in advance.

The lens frame 3 of the driven system unit is supported by the lens frame support portion 4. The lens frame support portion 4 is movable in the optical axis direction by two upper and lower round bar-shaped guide pins 5a and 5b. A coil spring 6 is attached to the upper guide pin 5a, and one end of the coil spring 6 is in contact with the motor M side of the lens frame support portion 4. Further, a plate-shaped rubber damper 8 is fixed to the upper side surface of the lens frame support portion 4, and two rotatable nut receiving pins 7a and 7b are attached so as to penetrate the rubber damper 8. There is. When the drive system unit is attached to the driven system unit, the nut receiving pins 7a and 7b are pressed against the nut 2 by the action of the coil spring 6, so that the lens frame 3 moves in conjunction with the nut 2. Become.

With this configuration, when the drive system unit is mounted on the driven system unit, the lead screw 1 is simply located between the two nut receiving pins 7a and 7b, and the two nut receiving pins 7a and 7b The drive system unit is brought closer to the driven system unit so that the nut 2 is located on the right side of 7b, and it suffices to fix the drive system unit at a predetermined position, which simplifies the assembly work. The positional relationship between the drive system unit and the driven system unit is set such that a clearance is formed between the nut 2 and the rubber damper 8.

Next, the operation of this embodiment will be described.

When the lead screw 1 rotates in accordance with the rotation of the motor M, the nut 2 screwed to the lead screw 1 is subjected to a force to follow the lead screw 1 and rotate due to friction. And since there is the above clearance, the nut 2 rotates only slightly (see FIG. 4). However, when the corner of the nut 2 hits the rubber damper 8, the nut 2 is prevented from further rotating, and thereafter, the nut 2 starts to move in the axial direction of the lead screw 1 by the action of the screw. Since the kinetic energy is transmitted to the lens frame 3 via the nut receiving pins 7a and 7b, the lens frame 3 moves in conjunction with the nut 2.

The impact at the moment when the corner of the nut 2 hits the rubber damper 8 is absorbed by the elastic action of the rubber damper 8, so that no vibration or abnormal noise is generated and the lens frame 3 is smoothly moved. Start straight movement. Even if the lead screw 1 is slightly bent and shakes, a clearance is formed between the nut 2 and the rubber damper 8, so that the entire linear portion of the outer circumference of the nut 2 is covered with the rubber damper 8. Since the nut receiving pins 7a and 7b are not pressed and the nut receiving pins 7a and 7b are rotatable, no force is applied to the lead screw 1 in the radial direction, so that no malfunction occurs.

As described above, the connection work between the drive system unit and the driven system unit at the time of assembly can be easily performed without impairing the conventional advantages.

FIG. 5 shows another embodiment of the lens driving device according to the present invention.

In this embodiment, two rectangular nuts 2 a and 2 b are screwed into the lead screw 1 and a coil spring 6 is attached. The coil spring 6 is located between the nuts 2a and 2b, and biases the rotatable nut receiving pins 7a and 7b via the washer 9 in the arrow direction. By doing so, the coil spring 6 does not expand or contract at all when the lens is driven, and the biasing force on the nuts 2a and 2b is constant, so the load on the motor M is also constant and the lens can be driven more smoothly. become.

Besides, almost the same effect as that of the previous embodiment is obtained. That is, when the drive system unit having the motor M, the lead screw 1, the nuts 2a and 2b, the coil spring 6, and the washer 9 is attached to the driven system unit, the washer 9 is slightly pushed toward the motor M side to remove the washer 9. A gap is formed between the nuts 2b into which the nut receiving pins 7a and 7b of the driven system unit are inserted, and the driving system unit is brought closer to the driven system unit as in the first embodiment, and is fixed at a predetermined position. do it. If the tips of the nut receiving pins 7a and 7b are sharpened, the work for forming the above-mentioned gap becomes easy. Needless to say, the advantages of the past have not been impaired.

The present invention is not limited to the above-described embodiments, and the rubber damper 8 can be attached to the nuts 2, 2a, 2b, for example. Further, the outer peripheral shape of the nuts 2, 2a, 2b may be formed by forming a part of the linear state, and may be, for example, a triangular shape or a semicircular shape.

[0022]

[Effect of device]

 According to the present invention, the drive system unit and the driven system unit can be easily connected to each other in such a manner that the rotation of the nut can be surely prevented, and the production efficiency and reliability of the product can be improved.

[Brief description of drawings]

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

FIG. 2 is a front view of the lens driving device shown in FIG.

3 is a side view of the lens driving device shown in FIG. 1. FIG.

FIG. 4 is a front view of the lens driving device shown in FIG. 1 during driving.

FIG. 5 is a side view of another embodiment of the lens driving device according to the present invention.

FIG. 6 is a side view of a conventional lens driving device.

[Explanation of symbols]

 1 lead screw 2 nut 3 lens frame 4 lens frame support 8 rubber damper

Claims (3)

[Scope of utility model registration request] 1. A screw type lens driving device for converting the rotational movement of a male screw member into a rectilinear movement of a female screw member, and moving the lens in the optical axis direction in conjunction with the rectilinear movement of the female screw member. Linear portions are formed on at least a part of the outer periphery of the screw member and at least a portion of the lens frame body that supports the lens, and the linear portion of the female screw member and the linear portion of the lens frame body are formed. Are opposed to each other, and rotation of the female screw member due to rotation of the male screw member is prevented by contact between the linear portion of the female screw member and the linear portion of the lens frame body. A lens driving device characterized in that a screw member is configured to move linearly. 2. The lens driving device according to claim 1, wherein an elastic member is interposed between the linear portion of the female screw member and the lens frame body. 3. A linear portion of the female screw member and the lens frame body, or between the elastic member and the linear portion of the female screw member, or between the elastic member and the lens frame body. A gap is formed between the two.
Alternatively, the lens driving device according to claim 2.