JPH0456931A - Zoom driving mechanism - Google Patents

Abstract

PURPOSE:To obtain a stably operating driving mechanism by providing the bearing of a transmission gear on a supporting member which supports a rotary cylinder so as to be rotated around an optical axis coming in slidably contact with the circumferential wall of the rotary cylinder. CONSTITUTION:The bearing of transmission gear 108 of a driving unit is provided at the supporting member 2 which supports the rotary cylinder 1 so as to be rotated coming in slidably contact with the circumferential wall of the rotary cylinder 1 of a lens-barrel unit. The relation of axes of two gears, the driving gear 1a of the rotary cylinder 1 and the transmission gear 108 engaged with it can be stably maintained by positioning and guiding with one member, and also, part of an external force applied by float-supporting the driving unit can be absorbed when it is applied. Thereby, the stably operating driving mechanism is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a zoom lens drive system for a camera with a built-in zoom lens.

(Prior Art) In recent years, compact cameras with a built-in zoom lens have been proposed, and such cameras have a motor and drive mechanism inside the camera to drive the zoom lens, and zoom using electric power. It has become.

In such a camera, as shown in FIG.
The driving force of the motor from 6 m is transmitted to the rotating tube of the lens barrel unit, and the photographic lens is zoomed by the rotational force of the rotating tube.

(Problem to be Solved by the Invention) However, in the configuration shown in FIG. 7, the gears on the rotary cylinder and the gears that mesh with each other in the drive unit move in the direction in which the distance between the shafts widens when driving. Power works.

On the other hand, the drive unit is usually 1720 mm in order to drive the lens barrel.
Since a deceleration of about 0 is applied and the force transmitted onto the rotating cylinder becomes quite large, the force acting in the direction of widening the distance between the axes of the gear on the rotating cylinder and the gear meshing with it also becomes large.

For this reason, the engagement ratio of the gears becomes small, and there is a risk that the gears may be damaged.

Furthermore, there is a similar danger if the lens barrel unit is pushed in from the outside.

The present invention aims to solve these problems and provide a drive mechanism that operates stably.

(Means for Solving the Problems) In order to solve the above problems, the zoom drive mechanism of the present invention includes:
The present invention is characterized in that a bearing for the transmission gear of the drive unit is provided on a support member that is in sliding contact with the peripheral wall of the rotating barrel of the lens barrel unit and rotatably supports the rotating barrel.

(Function) By positioning and guiding the drive gear of the rotary tube and the transmission gear that meshes with it using one member, the distance between the shafts of the two gears is maintained stably, and external forces are reduced by floatingly supporting the drive system unit. If it works, it will be able to absorb some of its power.

(Example) The present invention will be described in detail below with reference to the drawings.

The lens barrel unit has the following configuration.

As shown in Figure t52, the fixed part 4 is attached to the positioning pin 4a.
, b, and is positioned in the positioning holes 31+, i of the front frame 3 and then fixed. As shown in FIG.
is fitted into the fixing member 04 and rotatably held at the optical axis opening. The rotary barrel 1 has a gear portion 1a at the optical axis opening, receives a rotational force from the outside, and the rotation causes the forward barrel 5 to move back and forth by a mechanism (not shown), thereby zooming the photographic lens. Furthermore, the inner surface 1b of the rotating cylinder 1 is the bearing part 2 of the guide ring 2.
guided by f. Guide ring 2 has holes 2a-d
The mounting of the front frame 3 is fixed to the parts 3a-d via.

Next, the zoom drive unit will be explained.

As shown in FIGS. 1 and 5, the drive motor 101 is fixed to the base plate A51. motor binion 102
is connected to the rotor of the motor and the spring by a kick spring 110, and a constant torque is transmitted thereto.

In addition, the binion 102 is a stepped gear, and the reduction gear 1
03 and a gear portion 102b that meshes with the wing $109. Furthermore, Binion 102
Because it rotates at high speeds, if the gear tooth shape or the accuracy between the shafts of the gears that mesh are poor, abnormal noise will be generated and the camera will look unsightly when the camera is in operation. Therefore, in this embodiment, a helical gear gear 102, which has a high meshing ratio and has a noise-reducing effect, and a reduction gear 103 meshing with the helical gear gear 102 are used.

The reduction gears 103 to 107 are rotatably held on shafts provided on the base plate A51 and the base plate C53, and transmit the driving force of the motor 101. Clutch 108 is clutch gear A10
8n, clutch gear BIO8b, spring 108C1 shaft 10
It is composed of four points of 8d. clutch gear A108
a and B108b have cam surfaces that engage with each other on a plane perpendicular to the rotating shaft, and are pressed by a spring 108C to rotate the shaft 1.
It is rotatably held at 08d. The shaft 108d is held on one side by the base plate ASI and on the other side in the shaft hole 2e provided on the guide ring 2. With the configuration described above, the driving force of the motor 101 is transmitted to the rotating cylinder.

Next, holding the zoom unit will be explained.

The zoom unit has three base plates A31=BS2. C53, as shown in Figure 5, 103 to 107
The reduction gear is held rotatably, and the three plywood sheets are connected to the output section (meshing position r!i of 107 and 108).
With the exception of Furthermore, the zoom unit is fixed to the front frame 3, but as shown in Figures tp and a, the holes 53a and 5 in the base plate C53
3b and the hole 51a of the base plate A51 through a rubber bush 111 made of an elastic material, the front frame is fixed at the position 3e yf +H with a floating support structure, thereby enhancing the sound deadening effect.

Next, the holding of the clutch 108 will be described. As shown in Fig. 1 and Fig. t56, the pongee 108b of the clutch 108 has a shaft hole 2e provided on the guide ring 2 at one end near the gear engagement position, and a hole 51 provided on the base plate A at the other end.
It is rotatably held at b. As mentioned earlier, the inner surface 1b of the rotary cylinder 1 is supported by the bearing part 2f of the guide ring 2, so the gear 1a of the rotary cylinder and the clutch gear 108a
The distance between the axes is compensated with high precision by the component precision of the guide ring 2, and the two gears can be stably held against the force acting in the direction of spreading the axes between the gears 1a and 108a during driving. At the same time, the meshing ratio of the gears becomes smaller due to the wider distance between the shafts, and the risk of gear breakage can be avoided.

(Effects of the Invention) As mentioned above, in the present invention, since the drive gear of the lens barrel unit and the gear of the drive unit are positioned with one member, not only can the center axis be accurately aligned, but also When an external force is applied to the lens barrel unit, the two gears can be held together against the force that acts in the direction of separating the shafts, which also helps prevent damage to the gears.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention.
Both Figure and @2 are exploded perspective views, Figure 3 is a vertical cross-sectional view when wide, Figure 4 is a vertical cross-sectional view when telephoto, Figure 5 is an exploded cross-sectional view of the drive mechanism, and Figure 6 (a). and (b) is a partial sectional view. Figures 7 to 10 show a conventional example, where Figure 7 is an exploded perspective view, Figure 8 is a rear view, Figure 9 is a vertical sectional view, and Figure 10 is a partial sectional view. ing. 1... Rotating tube, 1a... Drive gear 10
8...Transmission gear, 2...Supporting member patent applicant Minolta Camera Co., Ltd. (α) ('b) Fig.

Claims (2)

[Claims] (1) It has a zoom lens, a lens barrel unit that holds the zoom lens, and a drive unit that drives the lens barrel unit, and a drive gear provided on the peripheral wall of the rotating cylinder of the lens barrel unit, and In the camera, the transmission gear that transmits power to the drive gear meshes with the camera to drive the zoom lens, and the support member that slides on the peripheral wall of the rotary tube and supports the rotary tube so as to rotate around the optical axis. A zoom drive mechanism characterized in that a bearing for the transmission gear is provided. (2) The zoom drive mechanism according to claim 1, wherein the drive unit is supported in a floating manner.