JPS60163014A - Lens barrel for zoom lens - Google Patents

Abstract

PURPOSE:To prevent generation of a looseness in the optical axis direction of a rod by forming a hole in at least one of a holding plate and an end plate side along the optical axis, placing an absorbing member of a dimensional error in this hole, and fixing the rod through this absorbing member. CONSTITUTION:An end plate 6 is placed on one end of a fixed cylinder 4, and also a holding plate 5 is placed on the other end. In this case, a hole is formed in at least one of the holding plate 5 and the end plate 6 side, and in this hole, for instance, a coil spring is placed as an absorbing member of a dimensional error, and a rod is fixed through this absorbing member 15. According to such a constitution, the rod can be pressed along the optical axis, therefore, even if a dimensional error is generated between the fixed cylinder and the rod, no looseness is generated in the optical axis direction, and this lens barrel is suitable for a mass production.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a zoom lens barrel suitable for video cameras and the like.

[Background of the invention]

In conventional zoom lens barrels, each part was machined with high precision to eliminate misalignment and wobbling of the rod in the optical axis direction. However, even if each part is machined with high precision, dimensional errors will occur when producing in large quantities, and it is impossible to eliminate even the slightest variation.In some cases, the rod is longer and presses against the presser plate. If the rod is too short, the gap between the rod and the cam ring becomes too large, causing play in the cam ring. Conversely, if the rod is too short, the rod becomes loose in the optical axis direction, reducing optical performance. I let it happen. In other words, if the backlash is large, the image forming plane will move because the variable magnification system movable frame and the correction system movable frame will move by the amount of backlash due to changes in posture during shooting, especially between upward and downward postures. This poses a major problem in that it degrades performance. Furthermore, in recent years, plastic lens barrels have been rapidly put into practical use in order to reduce manufacturing costs and weight. However, in the case of plastic molded products, it is difficult to control the above-mentioned play in the optical axis direction due to variations in molding conditions and unbalanced contraction of the tree fat due to the shape and pressure, which is an obstacle to its practical application. was.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens barrel that eliminates the drawbacks of the prior art described above and eliminates rattling of the rod in the optical axis direction.

[Summary of the invention]

To achieve this objective, the present invention forms a hole in the holding plate or fixed tube end plate that identifies the rod, and inserts dimensional error absorbing members such as pins, balls, springs, screws, etc. into the hole. The feature is that the rod is placed in place and the rod is fixed through the K, and the rod is pressed in the optical axis direction to absorb backlash.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a zoom lens barrel according to the present invention, in which 1 is a zoom ring, 2 is a zoom pin, 5 is a cam ring, 4 is a fixed barrel, 5 is a holding plate, and 6 is an end. plate, 7 is a variable power lens holding frame, 8 is a correction lens holding frame, 9 is a cam follower, 10 is a rod s LI I L! And, the lens is al.

An end plate 6 is integrally formed at one end of the fixed cylinder 4,
Further, a presser plate 5 is arranged at the other end. A cam ring 3 is rotatably housed between the end plate 6 and the holding plate 5. A zoom ring 1 and a cam ring 3 located on the outer periphery of a fixed barrel 4 are rotated together by a zoom pin 2. Also, the end plate 6 and the presser plate 5
A rod 10 is fixed to. A variable power lens holding frame 7 and a correction lens holding frame 8 are slidably fitted onto this rod 10. Since the rod 10 is arranged parallel to the optical axis, when both holding frames 7.8 move along the rod 10, it will move along the optical axis.

Each of the two retaining frames 7.8 has a cam follower 9, which is press-fitted into the groove of the cam ring 3. The groove of the cam R3 is formed in the circumferential direction with a component in the optical axis direction.

Because of this configuration, when the zoom ring 1 is rotated,
The cam ring 3 connected by the zoom pin 2 also rotates.

Since the cam follower 9 is fitted into the groove of the cam ring 6, the rotation of the cam ring 3 is achieved by guiding the variable power lens holding frame 7 and the variable power lens holding frame 8 onto the optical axis by the rod 10. The zooming operation is thereby achieved. The rod 10 is pressed against either the holding plate 5 or the end plate 6. Therefore, even if an error occurs in the lengths of the fixed cylinder 4 and the rod 10, the error can be absorbed.

FIG. 2 is an enlarged view showing a specific example of a method for suppressing part A of the end plate 6 in FIG. It is a set screw. By pressing the fixed cylinder 4 and the rod 10 by the difference in length, that is, by the amount of backlash, the rod backlash can be absorbed.

FIG. 3 is an enlarged view showing another specific example similar to FIG.
12 is a pressing pin, and 13 is an adhesive. Similar to the initial warp sealing screw 11, this is a method of pressing with a suppressing pin 12 by the length error between the fixed cylinder 4 and the rod 10 and bonding with an adhesive 13.

FIG. 4 shows another specific example similar to the above.

Components corresponding to those in Figure 1 are given the same reference numerals, and 14
is a pressed ball. Similar to the pressing bottle 12 in the previous example, the pressing ball 1
This is the method of pressing and adhering in Step 4.

FIG. 5 shows another specific example similar to the above, in which parts corresponding to those in FIG. 1 are given the same reference numerals, 15 is a coil spring, and 16 is a spring holder.

This is a method of pressing with a coil spring 15 and fixing the spring with a spring holder 16 in the same way as the pressing object.

FIG. 6 shows another specific example different from the previous example, and parts corresponding to those in FIG. 1 are given the same reference numerals, and 17 is a slotted countersunk screw. This is a method in which the rod is pulled in the opposite direction to the slotted countersunk screw 17 to absorb rod play. Similar effects can also be obtained with similar screws.

FIG. 7 shows another specific example similar to FIG. 6, and the same reference numerals are given to the same parts as in FIG. 1, and 18 is a leaf spring. This absorbs the rod by pressing the neck of the rod with a plate as shown in the figure. FIG. 8 is a perspective view of a specific example of the leaf spring 18 shown in FIG. It is bent like a box.

Since it is curved in a U-shape, it can be easily attached by, for example, fitting the presser plate 5 between them.

In this way, the rod is pressed against the presser plate 5 or the end plate 6 to absorb the looseness, so even if the fixed tube 4 is molded from plastic, it is possible to absorb the looseness due to variations in dimensional errors. I can do it.

〔Effect of the invention〕

As explained above, according to the present invention, the rod can be pressed along the optical axis, so even if there is a dimensional error between the fixed tube and the rod, rattling in the optical axis direction will not occur, and conventional It is possible to provide a zoom lens barrel with excellent functions and suitable for mass production, excluding the technical drawbacks.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a zoom lens barrel according to the present invention, and FIGS. 2, 3, and 4. 5, 6, and 7 are cross-sectional views showing specific examples of the rod pressing method shown in FIG. 1, and FIG. 8 is a sectional view of the leaf spring 1 shown in FIG.
FIG. 8 is a perspective view showing a specific example of No. 8; 1...Zoom ring, 2...Zoom pin, 5...Cam ring. 4... Fixed tube, 5... Holding plate, 6... End plate, 7...
... Variable power lens holding frame, 8... Correction system lens frame, 9
...Cam follower, 10...Rod, 11...
Slotted set screw, 12... Bottle, 14... Ball, 15
...Coil spring, 17...Screw, 18...Plate spring 10th 20th 3η 4″' 54th 60th District 7 Procedural amendment (voluntary) Case indication 1982 patent application Name of invention No. 17021 Relationship to the zoom lens barrel correction case Name of patent applicant (510) Co., Ltd.
Address Address: 1 [X1 Marunouchi-5-1, Chiyoda-ku, Tokyo]
No. 1, Hitachi, Ltd. Phone number: 212-1111
(Main representative) Target of correction Detailed explanation of the invention of Akira Tatami and the drawings (21 Doubou, page 8, line 7 "Correction system lens frame"
is corrected to "correction system lens holding frame". (Correct Figure 51, Figure 1fi, Figure 5 as shown in Attachment Sheet Figure 6.

Claims (1)

[Claims] A cam ring is rotatably housed between an end plate at one end of the fixed cylinder and a presser plate placed at the other end, a rod is fixed between the end plate and the presser plate, and light is emitted by the rotation of the cam ring. In a zoom lens barrel having a variable power lens holding frame and a correction system lens holding frame guided by the rod so as to move in the axial direction, the rod is moved along the optical axis to the holding plate and the end plate. A zoom lens barrel characterized in that a hole is formed in at least one of the sides, a dimensional error absorbing member is disposed in the hole, and the rod is fixed via the absorbing member.