JPH0416808A - Zooming device for camera and support device for driving motor with power transmission system - Google Patents

Abstract

PURPOSE:To reduce zooming noise by transmitting power by the frictional contacting between a driving roller and a friction roller instead of initial-stage gear engagement. CONSTITUTION:The driving motor 32 is supported on one of a couple of support substrates 34 with a stepped screw 35, which is at an eccentric position to the driving roller 32a; and the driving motor 32 can turn around the stepped screw 35. Then the friction roller 36a which comes into frictional contact with the driving roller 32a of the driving motor 32 is supported on the support substrate 34 of a gear box 30. The friction roller 36a, therefore, comes into strong frictional contact with the driving roller 32a with rotary moment applied by a leaf spring 44 at all times. Consequently, the generation of noise at the dynamic power transmission part of an initial stage can be suppressed and the zooming noise is reducible to a low level.

Description

TECHNICAL FIELD The present invention relates to a camera zooming device, and particularly to a support structure for a drive motor thereof.

"Prior art and its problems" An electric zoom lens transmits the rotation of a drive motor to a zooming member, such as a cam ring, through a power transmission system, and uses a cam groove provided in the cam ring to move the variable magnification lens group along the optical axis. Perform zooming by moving in the direction. Conventionally, the power transmission system is
Gear trains are widely used, and in an electric zoom lens having a gear train, zooming noise (noise) due to meshing of the gear train is unavoidable during zooming.

"Object of the Invention" An object of the present invention is to reduce this zooming noise.

The present invention more broadly relates to a device for transmitting the rotation of a drive motor to a power transmission system, in which noise generated between the rotation shaft of the drive motor and the driven shaft of the first stage receiving the power transmission is further reduced. The purpose is to obtain a support structure for a drive motor that allows for

"Summary of the Invention" As a result of studying the location where zooming noise occurs in a conventional zooming device using a gear train, the present inventor found that the first stage gear meshing part that transmits the rotation of the drive motor, that is, the rotation shaft of the drive motor. It was discovered that the area where the pinion meshes with the gear that meshes with it generates a lot of noise, and a device that can reduce the noise at this initial stage meshing area was developed.

The present invention reduces noise by transmitting power through frictional contact between a drive roller and a friction roller, instead of gear meshing in the first stage, and also minimizes slippage between the two. The drive motor is rotatably attached to the support substrate of the motor so as to be rotatable around an eccentric shaft eccentric to the shaft, and the drive motor is biased to rotate around the eccentric shaft in a direction in which the drive roller approaches the friction roller. It is characterized by

According to this configuration, since the power transmission system includes a driving roller installed on the rotating shaft of the drive motor and a friction roller that makes frictional contact with this driving roller, the gear meshing of the first stage, which has the loudest noise, is No noise is generated. Since this drive motor rotates and is biased in the direction in which the drive roller approaches the friction roller, it is difficult for slippage to occur between the two, and even if both rollers are worn out, the drive motor is reliably powered. can be transmitted. The biasing force applied to the drive motor is determined within a range in which the rotation of the driving roller is smoothly transmitted to the friction roller and in such a manner that no harmful load is applied to the motor.

The drive motor support structure of the present invention is applicable not only to camera zooming devices but also to drive motor support structures in general that have a power transmission system.

Note that the "drive motor j" referred to in the present invention includes a drive motor having a speed reducer, and it is sufficient if the output shaft (rotation shaft) thereof is provided with a driving roller.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. 4 and 5 are general views showing an embodiment of a camera zooming device according to the present invention. The cam ring 11, which is rotatably supported around the optical axis, has a front group cam 1ll12, a rear group cam groove 13, and a strobe cam a14. Pins provided on the front group lens and the rear group lens (both not shown) are fitted into the front group cam groove 12 and the rear group cam groove 13, respectively, and as the cam ring 11 rotates, these lens groups zooming is performed by moving in the optical axis direction.

A pin 18 of a moving block 17 guided by an optical axis direction rod 16 is fitted into the strobe cam 14. This moving block 17 is interlocked with a strobe light emitting block 21 via an interlocking lever 20 pivotally mounted on a shaft 19, and moves this strobe light emitting block 21 to a position corresponding to the focal length.

A sector gear 22 is fixed to the outer periphery of this cam ring 11, and a final gear 31 of a gear box 30 meshes with this sector gear 22.

The present invention provides a drive motor 3 in this gear box 3o.
The main feature is the support structure of No. 2, and its details are shown in FIGS.

The gearbox 30 has a pair of support substrates 34 that are integrated by a connecting post 33 . The drive motor 32 is supported by a stepped screw 35 on one of the pair of support substrates 34 . This stepped screw 35 is located at an eccentric position (
In the illustrated example, the head portion 35a is located on the upper side), and has a step portion 35b and a male thread portion 35c following the head portion 35a. The stepped portion 35 b is rotatably fitted into a support hole provided in the support substrate 34 , and the male threaded portion 35 c is screwed and fixed to the drive motor 32 . It can be rotated. Further, the axial length of the stepped portion 35b is set to be thicker than the plate thickness of the support substrate 34, and
A cushioning material (not shown) such as rubber is inserted into the gap S (FIG. 3) formed between the two. By forming a gap between the drive motor 32 and the support substrate 34 in this way, it is possible to prevent the vibration noise of the drive motor 32 from being amplified by the support substrate 34.

A base portion of a leaf spring 44 is fixed to the support substrate 34, and a tip pressing portion 44a of the leaf spring 44 is connected to the drive motor 32.
is in contact with. This leaf spring 44 acts to give the drive motor 32 a rotational moment in the direction A in FIG. 1 about the stepped screw 35.

A friction roller 36 that makes frictional contact with the driving roller 32a of the drive motor 32 is provided on the support substrate 34 of the gear box 30.
a is supported. Therefore, the friction roller 36a is always in strong frictional contact with the driving roller 32a due to the rotational moment given by the selection spring 44.

The pair of support substrates 34 of the gear box 30 further include a first gear 36 coaxially integrated with the friction roller 36a.
b, a second gear 37a that meshes with this first gear 36b, a third gear 37b that is coaxial with this second gear 37a, a fourth gear 38a that meshes with this third gear 37b, and a coaxial body that is integral with this fourth gear 38a. Fifth gear 38b, this fifth gear 38
A sixth gear 39a that meshes with the sixth gear 39a, a seventh gear 39b coaxially integrated with the sixth gear 39a, and the final gear 31 that meshes with the seventh gear 39b and the sector gear 22 are supported. The rotation of the fourth gear 3 g' a is also transmitted to the slit disk 42 of the photo ink converter 41 via the branch gear 40 . Photo interrupter 4
1 detects passage of the slit 42a of the slit disk 42 to detect the rotational position of the sector gear 22, that is, the focal length.

This device having the above configuration has a friction roller 36a that comes into frictional contact with the driving roller 32a when the drive motor 32 is driven in the forward and reverse directions.
rotates. Then, the first gear 36b, second gear 37a, . . . seventh gear 39b, which are coaxially integrated with the friction roller 36a,
, the gear train of the final gear 31 rotates in forward and reverse directions, and the sector gear 2
The cam ring 11, which is integral with the cam ring 2, rotates in forward and reverse directions to perform zooming.

According to the present invention, since the first-stage power transmission system of the drive motor 32 uses a friction contact system of the driving roller 32a and the friction roller 36a, very little noise is generated. A rotational moment is applied to the drive motor 32 by a leaf spring 44, and this rotational moment causes
A tendency is provided for the drive roller 32a to approach the friction roller 36a. Therefore, there is no risk of slippage occurring between the driving roller 32a and the friction roller 36a, and furthermore, even if both rollers are worn out due to long-term use, power is reliably transmitted. and both rollers 32
Even if a wears out, the rotational position (focal length) of the cam ring 11 can be detected by the photo ink club 41, so there is no practical problem.

If the rotational moment given by the leaf spring 44 is too large, it will impose an excessive load on the drive motor 32 and prevent its smooth rotation, so it is set to an appropriate magnitude within a range that does not interfere with the smooth rotation of the drive motor 32.

Although the present invention is applied to a zooming device for a camera in the above embodiment, the present invention is applicable to devices in general that transmit the rotation of a drive motor to a driven member via a power transmission system.

"Effects of the Invention" As described above, according to the present invention, in a camera zooming device in which a zooming member is driven by rotation of a drive motor, a driving roller is provided on the rotating shaft of the driving motor, and this driving roller is brought into frictional contact with a friction roller. As a result, noise generation in the first stage power transmission section, which was noisy in conventional gear trains, can be suppressed and zooming noise can be reduced to a low level. Since the drive motor is biased to rotate in the direction in which the driving roller approaches the friction roller, it is possible to minimize the slippage that occurs between both rollers, and even if both rollers are worn out, power can be transmitted to.

Furthermore, according to the second aspect, it is possible to reduce not only the zooming noise but also the noise generated during power transmission of the first stage of the drive motor.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the main parts showing the support structure of the drive motor according to the present invention, Figure 2 is an enlarged front view of the gearbox, Figure 3 is a plan view of the same, Figures 4 and 5 are of the camera. FIG. 1 is a front view and a plan view of a zooming device to which the present invention is applied. 30... Gear box, 21... Final gear, 32...
... Drive motor, 32a... Drive roller, 34...
Support board, 35...Stepped screw (eccentric shaft), 35a...
・Head, 35b...Stepped part, 35c...Male thread part, 3
6a...@rubbing roller, 36b, 37a, 37b, 38
a, 38b, 39a, 39 b--gear, 40...
・Branch gear, 41... Photo interrupter, 42...
- Slit disk, 42a... slit, 44... leaf spring (rotation biasing means), 44a... tip pressing portion. Patent applicant: Asahi Optical Industry Co., Ltd. Agent: Kunio Miura

Claims (2)

[Claims] (1) In a camera zooming device that transmits the rotation of a drive motor to a zooming member of a camera via a power transmission system, the power transmission system includes a driving roller provided on the rotating shaft of the driving motor, and a driving roller provided on the rotating shaft of the driving motor. a friction roller that is in frictional contact with the drive motor, the drive motor is rotatably attached to the support substrate of the motor around an eccentric shaft that is eccentric with respect to the rotation axis of the drive motor; 1. A camera zooming device, comprising means for rotationally biasing the eccentric shaft in a direction approaching the friction roller. (2) A driving roller provided on the rotating shaft of the drive motor and a friction roller that makes frictional contact with the driving roller are interposed in the power transmission system, and the driving motor is connected to an eccentric shaft eccentric to the rotating shaft. A means for rotating the drive motor about the eccentric shaft in a direction in which the drive roller approaches the friction roller is provided, the drive motor being rotatably attached to the support substrate of the motor. A support device for a drive motor having a power transmission system.