JPS61167284A - Vibration proofing structure of lens driving motor for video camera - Google Patents

Abstract

PURPOSE:To absorb surely the vibration of a motor by providing a vibration proof elastic member interposed between a video camera lens driving motor and a motor carrier with plural projections different in position on the motor side and on the carrier side. CONSTITUTION:An vibration proof elastic member 40 interposed between the video camera lens driving motor 26 and the motor carrier 29 is provided with plural projections on the front and back sides of a discoid part 40a. The projections 40b and 40c are set in their positions so that they are differently located on the motor side 26 and on the carrier side 29. An antivibrational bushing 41 of resilient material is fitted in a motor mounting aperture 29a of the carrier 29, a set screw 43 is passed through the bushing 41 and fitted with a resilient tube 42, the tube 42 and the screws 43 are passed through a stationary opening 40d of the resilient member 40 and screwed in a female thread 26a of the motor 26. Vibrations of the motor 26 are damped while passing through the projections 40b, discoid part 40a, an projections 40c to be transmitted to the carrier 29. The vibrations of the motor 26 that may be transmitted via screw 43 are absorbed by the vibration proof bushing 41.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a support structure for a motor that drives a lens for a video camera, and particularly to an anti-vibration structure thereof.

"Prior Art and its Problems" A video camera lens usually uses a motor for its zooming drive or focusing drive. FIG. 6 shows an example of a structure in which zooming is performed by a motor.
It rotates together with the cam ring 13 inside 2. Fixed lens barrel 12
A variator (variable magnification) lens frame 15 and a compensator (
Compensation) The lens frame 16 is supported, and the interlocking pin 17.18 provided integrally on the variator lens frame 15 and the compensator lens frame 16 connects to the cam groove 19.2 formed in the cam ring 13.
It's stuck at 0.

Reference numeral 21 indicates a focusing lens frame that is movably provided at the tip of the fixed lens barrel 12, and 22 indicates this focusing lens frame 2.
This is a focusing ring that moves the lens 1 forward and backward in the optical axis direction. Further, a master lens frame 23 is fixed to the rear end of the fixed lens barrel 12.

The zoom ring 11 has a zoom gear 2 on the outer periphery of its rear end.
5 is formed. This zoom gear 25 meshes with a pinion 28 provided on an output shaft 27 of a drive motor 26. Therefore, when the drive motor 26 is driven, the output shaft 2
7. The zooming ring 11 rotates via the pinion 28 and the zoom gear 25, and the cam ring 13 rotates in tandem with the zooming ring 11.

Then, the variator lens frame 15 and the compensator lens frame 16 move in the optical axis direction according to the relationship between the cam grooves 19 and 20, and the focal length of the entire lens system changes.

During zooming using the drive motor 26, when the vibrations of the drive motor 26 are transmitted to the lens side, it resonates with the lens barrel and produces unnecessary sound (noise), which may be recorded on the VTR or may be difficult to focus on. To avoid this, an elastic body 3 for vibration isolation is installed between the motor support plate 29 and the drive motor 26, which were conventionally provided integrally with the fixed lens barrel 12, to avoid misalignment and vibration of the screen.
0 is used to intervene.

FIG. 7 shows the details of the vicinity of this vibration isolating elastic body 30, and the motor support plate 29 has female screws 26 of the drive motor
A motor mounting hole 29a is drilled in accordance with the position a, and a cylindrical portion 30a that fits into the motor mounting hole 29a is provided in a protruding manner on the plate-shaped vibration isolating elastic body 30. This cylindrical part 30a
At the tip of the seat part 30b, the head of the fixing screw 31 comes into contact.
is formed, and a through hole 30c is bored at the end of this cylindrical portion 30a. The fixing screws 311± are inserted into the through holes 30c and screwed into the female threads 26a of the drive motor 26 in a state where the cylindrical portion 30a of the vibration isolating elastic body 30 is fitted into the motor mounting hole 29a of the motor support plate 29. , the drive motor 26 is attached and fixed to the motor support plate 29.

However, in this conventional vibration isolation structure, the plate-shaped vibration isolation elastic body 30 is sandwiched between the drive motor 26 and the motor support plate 29, and is tightened and compressed evenly by the fixing screws 31, so that sufficient vibration isolation is not achieved. It was not possible to obtain a vibration effect. That is, in the attached state shown in FIG. 6, the vibration isolating elastic body 30 is thinner overall than in the free state.
Hardness also increases. Therefore, the vibration absorption effect becomes smaller,
Vibrations generated by the drive motor 26 are not absorbed sufficiently and are transmitted from the motor support plate 29 to the lens side.

``Object of the Invention'' Based on the discovery of problems with the conventional vibration-proof structure, the present invention aims to provide a vibration-proof structure that more reliably absorbs the vibration of the drive motor and does not transmit it to the lens side. purpose.

"Summary of the Invention" The present invention achieves this object by providing a vibration-isolating elastic body interposed between a drive motor and its support body with a special shape structure. The present invention is characterized in that a plurality of protrusions are provided on the drive motor side and the support body side, respectively, to protrude and come into contact with these, and the positions of these protrusions are made different on the drive motor side and the support body side. According to this anti-vibration structure, the vibration generated by the drive motor is first transmitted to the protrusion of the elastic body, but since there is no protrusion on the opposite side of the elastic body that comes into contact with the support, the vibration is not supported. Vibration is not directly transmitted to the body and always undergoes the absorption action of an elastic body. Therefore, a reliable vibration-proofing effect can be obtained.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. 1 to 5 show embodiments of the present invention, and FIGS. 6 and 7 show embodiments of the present invention.
Elements that are the same as those in the figures are given the same reference numerals. As shown in FIGS. 3 and 4, the vibration isolating elastic body 40 has a single unit shape.
A plurality of protrusions 40b and 40c are provided on the front and back sides of the disc-shaped portion 40a, that is, on the drive motor 26 side and the motor support plate 29 side. The protrusion 40b and the protrusion 40c are arranged so that they are not positioned in a straight line, that is, the drive motor 26
The positions are set so that the positions are different between the side and the motor support plate 29 side. The protrusion 40b is connected to the drive motor 26.
The protrusion 40c abuts on the motor support plate 29.

A vibration-proof bushing 41 made of an elastic material is fitted into the motor mounting hole 29a of the motor support plate 29, and a fixing screw 43 covered with a heat-shrinkable elastic tube 42 is inserted into the vibration-proof bushing 41. Ru. The elastic tube 42 and the fixing screw 43 are further inserted into the fixing hole 40d of the vibration isolating elastic body 40, and the tip of the fixing screw 43 is electrically connected to the internal thread 26a of the drive motor 26.

The amount of compression of the vibration isolating elastic body 40 by the fixing screw 43 is the fifth
As shown in the figure, the disk-shaped portion 40a is restricted so that it does not come into contact with the drive motor 26 and the motor support plate 29. That is, when the fixing screw 43 is tightened, the vibration isolating elastic body 40
The protrusions 40b and 40c are the drive motors 26 and 40c, respectively.
The disk-shaped portion 40a is deformed by coming into contact with the motor support plate 29, but even if the disk-shaped portion 40a is deformed, the drive motor 2
The tightening force of the fixing screw 43 is set so that it does not come into contact with the fixing screw 6 and the motor support plate 29. Elastic tube 42
can also have the role of a spacer tube that regulates the amount of tightening of the fixing screw 43.

According to the above vibration-proof structure, the vibration generated by the drive motor 26 is first transmitted to the protrusion 40b, but since the position of the protrusion 40b and the position of the protrusion 40c do not match, this vibration is directly transmitted. It is not transmitted to the motor support plate 29. In other words, the vibration of the drive motor 26 is always caused by the protrusion 40b.
The vibrations reach the motor support plate 29 while passing through the disc-shaped portion 40a and the protrusion 40c, and are attenuated while passing through these, so the vibrations transmitted to the motor support plate 29 are much smaller than in conventional devices. Become. Furthermore, vibrations of the drive motor 26 that may be transmitted via the fixing screw 43 are absorbed by the anti-vibration bushing 41.

``Effects of the Invention'' As described above, according to the present invention, special positions are set on the front and back sides of the vibration-proof bony body interposed between the focusing or zooming drive motor and its support. The simple structure of providing the protrusion can effectively absorb the vibrations of the motor and prevent the vibrations from being transmitted from the motor support to the lens side. Therefore, it is possible to obtain a video image without lens out-of-focus or screen vibration caused by vibration of the drive motor, and without unpleasant vibration sounds recorded.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the main parts showing an embodiment of the vibration isolation structure of a lens drive motor for a video camera according to the present invention, Fig. 2 is a cross-sectional view of the same in an assembled state, and Fig. 3 is an elastic body for vibration isolation. 4 is a side view of the unit, FIG. 5 is a side view of the same deformed state, and FIG. 6 is a vertical cross-sectional view showing an example of the vibration isolation structure of a conventional video camera lens and its drive motor. FIG. 7 is an exploded perspective view of the main parts. 11... Zooming ring, 25... Zoom gear, 26
... Drive motor, 28 ... Binion, 29 ... Motor support plate (body), 40 ... Vibration-proofing elastic body, 40a.
...Disk-shaped portion, 40b, 40c...Protrusion, 41...
Anti-vibration bushing, 42...Elastic tube, 43...Fixing screw. Patent applicant: Asahi Optical Industry Co., Ltd. Agents: Kunio Miura and Shigeru Matsui

Claims (1)

[Claims] (1) In a motor vibration isolation structure in which an elastic body for vibration isolation is interposed between a drive motor for zooming or forcing a video camera lens and a support for this drive motor, A video camera characterized in that the elastic body is provided with a plurality of protrusions that protrude from the drive motor side and the support body side and come into contact with these, and the positions of these protrusions are different between the drive motor side and the support body side. Anti-vibration structure for lens drive motor.