JP2001264613A - Lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device capable of preventing a nick from being caused in a groove for guiding a roller by supporting the roller in a moving barrel through an elastic member and forming the outer peripheral surface of the roller so that its cross section may be circular-arc-shaped. SOLUTION: The 2nd and the 3rd rollers 16b and 16c of a roller train 16 are supported in the moving barrel 14 through the elastic members 50 and 56. The outer peripheral surfaces of the rollers 16a to 16b are formed to be circular-arc-shaped. Even when the rollers 16b and 16c give impact to the inner wall surface of a straight advance groove 20, the elastic members supporting the rollers 16b and 16c are elastically deformed to absorb the impact force. In such a case, the rollers 16b and 16c come into contact with the inner wall surface of the groove 20 along an outer peripheral surface formed to be circular- arc-shaped, so that they do not exert unnatural force on the inner wall surface of the groove 20 and the nick is not caused on the inner wall surface of the groove 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens device,
In particular, the present invention relates to a lens device for a television camera having a zoom function.

[0002]

2. Description of the Related Art In a lens apparatus for a television camera having a zoom function, a variable magnification operation is performed by moving two lens groups, a variator lens and a compensator lens, disposed in a lens barrel along an optical axis. Done.

[0003] These zoom lens groups are generally guided in the optical axis direction using a row of rollers. That is, a roller row is formed by arranging a plurality of rollers along the optical axis at an outer peripheral three-part position of the moving cylinder, and this roller row is formed along the optical axis at an inner peripheral part of the fixed cylinder at the three-part position. The movable cylinder is linearly guided along the optical axis by engaging with the rectilinear groove.

However, in the case of a guide using rollers, when the zoom operation is performed at a high speed, a large inertial force is generated in the moving cylinder at the time of a stop, and the rollers give a strong impact to the inner wall surface of the rectilinear groove. Disadvantageously occurs. Then, if a dent is formed on the inner wall surface of the groove in this way, there is a disadvantage that the movement of the lens group is not performed smoothly and the image shakes during the zoom operation.

[0005] To solve this drawback, Japanese Patent Laid-Open Publication No.
Japanese Patent Application Laid-Open No. 60277 proposes a moving cylinder in which a roller is attached via an elastic member.

[0006]

However, in the case of JP-A-8-160277, since the inner wall surface of the straight groove and the roller surface that comes into contact with the straight wall are formed in parallel,
When the roller bends via the elastic member due to the impact,
The roller surface is not parallel to the inner wall surface of the rectilinear groove, and an excessive force is applied. As a result, there still remains a problem that a dent is formed on the inner wall surface of the straight groove.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lens device capable of preventing a dent from being formed in a groove for guiding a roller.

[0008]

According to the present invention, in order to achieve the above object, a roller provided on an outer peripheral portion of a movable barrel for holding a lens is engaged with a groove formed on an inner peripheral surface of a fixed barrel. In the lens device for moving the moving cylinder in the optical axis direction, the roller has a shaft portion supported by the moving cylinder via an elastic member, and an outer peripheral surface thereof is formed in an arc-shaped cross section. A lens device is provided.

In order to achieve the above object, according to the present invention, a plurality of rollers are provided along the optical axis on an outer peripheral portion of the movable cylinder, and at least one of the rollers is an elastic member. 2. The lens device according to claim 1, wherein the lens device is supported by the moving cylinder via a lens.

According to the present invention, even when the moving cylinder suddenly stops and the roller gives an impact to the groove, the elastic member supporting the roller elastically deforms and absorbs it. By making the outer peripheral surface into an arc shape, even if the roller shaft is bent by an impact, it does not apply an excessive force because it comes into contact with the inner wall surface of the rectilinear groove along this arc surface.
There is no dent. In addition, by making the outer peripheral surface of the roller have an arc-shaped cross section, the roller comes into contact with the groove and rolls at a point, thereby providing a further effect that a smooth guide with little operating noise is possible.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the lens device according to the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 and 2 are a side sectional view and a front sectional view, respectively, showing the structure of a main part of a zoom lens apparatus to which the present invention is applied.

In FIG. 1, reference numeral 12 denotes a variator lens constituting a zoom lens, which is held by a movable barrel 14. At the position of the outer periphery of the movable cylinder 14 divided into three parts,
Each of the roller rows 16 is provided.
6 is engaged with a rectilinear groove 20 formed at an inner peripheral portion of the fixed cylinder 18 divided into three parts. The rectilinear groove 20 is formed along the optical axis. When the roller row 16 rolls in the rectilinear groove 20, the moving cylinder 14 is linearly guided along the optical axis.

A driving roller 22 is provided on the outer periphery of the movable cylinder 14. The driving roller 22 is engaged with a cam groove 26 formed in the cam cylinder 24.
The cam barrel 24 is driven and rotated by driving means (not shown), and the cam barrel 24 is rotated, whereby the moving barrel 14 is rotated.
Move along the optical axis. A stopper 28 is mounted on the outer peripheral surface of the cam cylinder 24, and the stopper 28 is provided on an arm 30 provided on the outer peripheral portion of the fixed cylinder 18.
And restricts the rotation range of the cam cylinder 24.

FIG. 3 is a plan view showing the structure of the engaging portion between the roller row and the rectilinear groove. As shown in FIG.
6 are four rollers 16a, 16 arranged along the optical axis.
b, 16c and 16d. And
The first roller 16a and the fourth roller 16d are in contact with the inner wall surface 20a on one side of the rectilinear groove 20, respectively. The second roller 16b and the third roller 16c are on the other side of the rectilinear groove 20, respectively. It is in contact with the inner wall surface 20b.

FIG. 4 shows the first roller 16a and the second roller 1
FIG. 6B is a side cross-sectional view illustrating the structure of the support portion of FIG.

First, the support structure of the first roller 16a will be described. The first roller 16a is a ball bearing 3
The outer ring 32a is covered with a roller 34 made of resin. The inner ring 32b of the ball bearing 32 is fixed to a tip end portion 36a of the support shaft 36 with a screw 38, so that the outer ring 32a is rotatably supported on the support shaft 36. The support shaft 36 has a screw portion 36b at its base end.
The first roller 16 a is attached to the movable cylinder 14 by screwing the screw portion 36 b into a screw hole 40 formed in the movable cylinder 14.

The outer ring 32a of the ball bearing 32
The outer surface of the roller 34 is formed in an arc-shaped cross section. As described above, the outer peripheral surface is formed in an arc-shaped cross section, so that the first roller 16a
In this case, the inner wall surface 20a is brought into contact with the inner wall surface 20a at a point, and the operating noise during rolling is reduced.

Next, the support structure of the second roller 16b will be described. The second roller 16b is connected to the first roller 16
As in the case of a, the outer ring 42a of the ball bearing 42 is covered with a roller 44 made of resin. The inner ring 42b of the ball bearing 42 is fixed to the tip end 46a of the support shaft 46 with a screw 48, so that the outer ring 42a
Is rotatably supported with respect to.

The support shaft 46 has a rubber support ring 50 attached to the outer periphery of an intermediate portion 46b. The support ring 50 is fitted into a mounting hole 52 formed in the moving cylinder 14. The support shaft 46 has a threaded portion 46c formed at the base end thereof, and the threaded portion 46c is inserted into a hole 54 formed in the movable cylinder 14 to form a ring-shaped rubber seat. The second roller 16b is attached to the movable cylinder 14 by screwing the nut 58 through 56.

Incidentally, as described above, the second roller 16b
The support shaft 46 is supported by the movable cylinder 14 via a rubber support ring 50 and a rubber seat 56. In this way, by supporting the support shaft 46 via the elastic member, even if the second roller 16b receives a strong load in the lateral direction, the load can be absorbed by the elastic member. Become. Accordingly, even when the second roller 16b presses the inner wall surface 20b of the rectilinear groove 20 with a strong force, a dent is suppressed on the inner wall surface 20b of the rectilinear groove 20.

The outer ring 42a of the ball bearing 42
The roller 44 coated on the first roller 16a
Similarly to the above, the cross-sectional shape of the outer periphery is formed in an arc shape. Thereby, the operating noise during rolling is reduced as in the case of the first roller 16a.

Further, by forming the outer peripheral surface in an arc shape in this manner, when the support shaft 46 is bent, the second roller 16b moves along the outer peripheral arc surface of the inner wall surface 20b of the rectilinear groove 20. Therefore, no excessive force is applied to the inner wall surface 20b of the rectilinear groove 20. Thereby, the second roller 16
Even if b presses the inner wall surface 20b of the rectilinear groove 20 with a strong load, no dent is formed on the inner wall surface 20b of the rectilinear groove 20.

The first roller 16a and the second roller 16b
The configuration is as described above. The third roller 16c has the same configuration as the second roller 16b.
6d has the same configuration as the first roller 16a. Therefore, for the third roller 16c and the fourth roller 16d,
The same components as those of the first roller 16a or the second roller 16b are denoted by the same reference numerals, and description thereof will be omitted.

The operation of the zoom lens apparatus according to the present embodiment having the above-described structure is as follows.

Moving cylinder 1 holding variator lens 12
When the cam barrel 24 is rotated, the cam 4 linearly moves by an amount of displacement of a cam groove 26 formed in the cam barrel 24 in the optical axis direction. At this time, the movable cylinder 14 is guided so as to move linearly by the roller row 16 provided on the outer peripheral part rolling in a straight groove 20 formed on the inner peripheral surface of the fixed cylinder 18. . Further, at this time, the rollers 16a to 16d constituting the roller row 16 each have an outer peripheral surface formed in an arc shape, and thus come into contact with the inner wall surface of the rectilinear groove 20 at a point. As a result, a smooth guide with little operating noise can be provided.

By the way, in order to perform a zoom operation at high speed,
When the cam cylinder 24 is rotated at a high speed, a large inertia force acts on the movable cylinder 14 when stopped. As a result, when the movable cylinder 14 stops, the roller row 16 gives a large impact to the inner wall surface of the rectilinear groove 20.

However, in the zoom lens device according to the present embodiment, the second roller 16b
And the third roller 16 c are supported by the movable cylinder 14 via elastic members (the support ring 50 and the seat 56), so that these rollers 16 b and 16 c
Even if it is pressed by b, the impact force can be absorbed by the elastic deformation of the elastic member.

At this time, the rollers 16b, 16c
Absorbs the impact force due to the bending of the support shaft 46. However, when the support shaft 46 is bent, the rollers 16b and 16c come into contact with the inner wall surface 20b of the rectilinear groove 20 along the circular arc surface on the outer periphery thereof. In addition, an excessive force is not applied to the inner wall surface 20b of the rectilinear groove 20, thereby preventing a dent from being formed on the inner wall surface of the rectilinear groove 20.

As described above, according to the zoom lens apparatus of the present embodiment, the elastic members supporting the rollers 16b and 16c are elastically deformed even when the roller row 16 gives an impact to the rectilinear groove 20. This can be absorbed. Further, since the outer peripheral surfaces of the rollers 16b and 16c are formed in an arc shape, even if the support shaft 46 is bent by an impact, the rollers 16b and 16c keep the inner wall surface of the rectilinear groove 20 along the arc surface. Due to the contact, no excessive force is applied to the inner wall surface of the rectilinear groove 20. Thus, the straight groove 2
It is possible to effectively prevent a dent from being formed on the inner wall surface of the zero.

In this embodiment, the second roller 16
Although b and the third roller 16c are configured to be supported by an elastic member, the first roller 16a and the fourth roller 16d may be supported by an elastic member. Further, all the rollers 16a to 16d may be supported by elastic members.

Also, in the present embodiment, an example has been described in which the present invention is applied to the moving mechanism of the variator lens 12 constituting the zoom lens. However, a lens using all the roller rows and the rectilinear grooves including the compensator is used. It can be applied to a moving mechanism.

[0033]

As described above, according to the present invention,
Even if the moving cylinder is suddenly stopped and the roller gives an impact to the groove, the elastic member supporting the roller is elastically deformed and absorbs it, and the outer peripheral surface of the roller is formed in an arc shape. Therefore, even if the roller shaft is bent by an impact, the roller contacts the inner wall surface of the rectilinear groove along this arc surface, so that no excessive force is applied and no dent is formed. In addition, by making the outer peripheral surface of the roller an arc-shaped cross section, the roller comes into contact with the groove at a point and rolls,
An additional effect that a smooth guide with less operation noise is enabled is also provided.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a main part of a zoom lens device to which the present invention is applied.

FIG. 2 is a front sectional view showing a configuration of a main part of a zoom lens device to which the present invention is applied.

FIG. 3 is a plan view showing a structure of an engaging portion between a roller row and a rectilinear groove.

FIG. 4 is a cross-sectional side view showing a configuration of a first roller and a second roller.

[Explanation of symbols]

12: Variator lens, 14: Moving cylinder, 16: Roller row, 16a, 16b, 16c, 16d: Roller, 18
... Fixed cylinder, 20 ... Straight groove, 20a, 20b ... Inner wall surface, 2
2 ... Drive roller, 24 ... Cam cylinder, 26 ... Cam groove, 28
... stopper, 30 ... arm, 32 ... ball bearing,
34 roller, 36 shaft, 38 screw, 40 screw hole, 42 ball bearing, 44 roller, 46 shaft, 48 screw, 50 support ring, 52 mounting hole, 5
4 hole, 56 seat, 58 nut

Claims (2)

[Claims] 1. A lens for moving a movable barrel in an optical axis direction by engaging a roller provided on an outer peripheral portion of a movable barrel holding a lens with a groove formed on an inner peripheral surface of a fixed barrel. In the apparatus, the roller has a shaft portion supported by the moving cylinder via an elastic member, and an outer peripheral surface thereof is formed in an arc-shaped cross section. 2. A plurality of rollers are provided along an optical axis on an outer peripheral portion of the moving cylinder, and at least one of the rollers is provided.
2. The lens device according to claim 1, wherein the two rollers are supported by the movable cylinder via an elastic member.