JPS59164513A - Groove cam mechanism - Google Patents

Abstract

PURPOSE:To reduce load unevenness and friction, to reduce the clearance between a bearing and a groove, and to prevent an image flicker and an out- of-focus image by pressing the bearing against a groove surface by a member such as a spring. CONSTITUTION:One groove is provided with two bearings 2a and 2b coaxially with a bearing shaft 6, and the spring and another elastic member 8b, etc., are provided to the bearing shaft 6 so that one bearing 2b is prssed against the groove surface 3b. Consequently, only one surface of the bearing 2b contacts the groove surface 3b, so loading uneveness and frictional resistance in operation decrease and the clearance between the bearing 2b and groove surface 3b is held small. This groove cam mechanism is applied to the zooming mechanism of a zoom lens to prevent an image flicker and an out-of-focus image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a groove cam mechanism, and particularly to a groove cam mechanism used in a zoom mechanism or a focus mechanism of a zoom lens.

Although the performance of recent zoom lenses has improved, the cam mechanism is not sufficient, so the image may shake as the lens moves during zooming, and the image may become blurry. However, various problems remain, such as operational noise and uneven load required to move the lens during operation.

These problems are largely due to the structure of the conventional grooved cam mechanism. FIG. 1 is a schematic diagram of a groove cam mechanism used in a zoom mechanism of a zoom lens, and FIG. 2 is a sectional view of a typical groove cam mechanism of a zoom lens currently used.

In Figure 1, 1 prevents the bearing from being removed, 2 is a bearing, 5 is a movable ring, and 6 is a groove for passing the bearing through. is cut diagonally. The movable ring 6 is structured to rotate in the A or B direction. 4#- with the fixed ring groove 4 for bearing passage
．． is cut horizontally. This is a holding ring that holds a zoom lens group with seven moving objects. Now, when the movable ring 6 is rotated in the direction A or B, the retaining ring 7 will move into the groove 4 of the fixed ring 4. Move to the left or right depending on the weather.

As shown in Figure 2, if the clearance between the bearing 2 and the groove is small, the bearing 2 will come into contact with both groove surfaces of the groove during operation, hindering free rotation and increasing the friction resistance. The cis friction noise due to load unevenness is increasing.

Furthermore, if the clearance between the bearing 2 and the groove is large, play in the retaining ring 7 will cause large image shaking, image blurring, etc. Note that 5 is a spanner.

As described above, the grooved cam mechanism conventionally used has a problem in that the clearance between the bearing 2 and the groove is poor, and the surface precision of the groove surface must be improved.

The present invention eliminates q-heavy unevenness during operation and reduces friction to reduce operating noise, and by reducing the clearance between the bearing and the groove, it is possible to prevent image shaking and image blurring. The purpose is to provide a grooved cam mechanism.

The characteristics of the grooved cam mechanism for achieving the purpose of the present invention are that a plurality of bearings are inserted into one groove coaxially with the bearing shaft, each bearing contacts only one groove surface of the groove, and At least one bearing is brought into contact with two groove surfaces of the groove, and the bearing shaft is provided with a member that presses at least one bearing among the plurality of bearings in the direction of the groove surface of the groove. .

Next, embodiments of the present invention will be described using the respective figures.

Figures 5-a and 5-b to 7 are explanatory diagrams of an embodiment of the present invention.

In Figure 5-a, two bearings 2a and 2b are provided with a bearing in one groove and the shaft 6 is coaxial, and a member 8b is attached to the bearing 6 so that one bearing 2b is pressed against and comes into contact with the groove surface 3b. It was established. In this embodiment, a case is shown in which the second bearings 2a and 2b are used, but a bearing of Fi2 or higher may also be provided in the groove. Further, a plurality of members 8b may be provided on each bearing shaft for each bearing. It is preferable to use an elastic member such as a spring, a leaf spring, or a comb as the member 8b in this embodiment.

FIG. In the figure, the bearing 2b is in contact with the groove surface 5b.

In this embodiment, the flat bearing 2a is the left groove surface 3a.
The bearings 2b are in contact with the right groove surface 3b.

By adopting such a configuration, only one side of the bearing comes into contact with the groove surface, which can be maintained.

Although this embodiment shows an example in which two bearings are inserted into one groove, it goes without saying that there may be two or more bearings. However, even if two or more bearings are inserted, it is necessary to ensure that at least one bearing is in contact with each of the two sides of the groove.

In this embodiment, the spacers 5a and 5b are arranged between the bearings 2a and 2b and between the bearings 2b and 2c to reduce the M frictional resistance of both bearings. Furthermore, if a groove cam mechanism is constructed using a plurality of grooves, such as a zoom mechanism of a zoom lens, the structure of the present invention can be adopted for each groove.

FIG. 4 shows two bearings 2a, 2b and 2c in each groove when two grooves are used.

2d is provided coaxially with the bearing shaft 6. The pot numbers assigned to each element in the figure are the same as those used in FIG. 3. Bearing arrangement F;i in the valley groove in the same figure
W. This is the same as in the embodiment shown in FIG. If such a configuration is adopted, the object of the present invention can be achieved better than the embodiment shown in FIG.

FIG. 5 shows the members 8a and 8b in FIG. 4 with a core rod 9a.

9b is an explanatory diagram of an embodiment in which 8 rods 9a and 9b are provided, and in this embodiment, members 8a and 8b are provided.
This is preferable because it prevents bowing and makes it easier to maintain normal function.

FIG. 6 is an explanatory diagram of an embodiment in which plate springs 8a' and 8b' are used as spring margins 9 of members 8a and 8b in FIG. 4.

In FIG. 7, two bearings are used in each of the two grooves, and members 8a and 8b are used for each bearing.

Using bearings 8c and 8d, bearings 2a, 2b, 2c,
2d is an explanatory diagram of an example in the case of pressing against the valley groove surface 3a or the groove surface 5b.

FIGS. 8 and 9 are explanatory diagrams of an embodiment in which the member 8 is provided with adjusting means for adjusting the force that presses the bearing, for example, on the groove surface side of the groove. As shown in FIG. 8, the structure is such that the force with which this bearing 2b is pressed against the groove surface can be adjusted freely by 1s14 using a push screw 10. In FIG. 9, a wedge 11 is inserted between the push screw 10 and the member 8 to obtain the same effect as in FIG. 8.

In these embodiments, a bearing is used in the groove cam portion of the zoom lens, and the bearing rotates during zoom operation to reduce frictional resistance, and each pull spring built into the shaft of the bearing prevents play between the groove and the bearing. With a mechanism that eliminates the need to operate, the operating force is stable and small, and high precision can be expected. Furthermore, in the present invention, depending on the quality of the spring and changes over time in the sliding ring, the force that presses the bearing against the groove part of the grooved cam fluctuates, and if it becomes impossible to absorb changes in the zoom operation force or play between the groove part and the bearing, By making it possible to freely adjust the strength of the spring, the force that presses the bearing against the groove can be adjusted to the optimum condition at all times, providing stable zoom operation, and even if the sagging becomes weaker over time, it can be reused. It has the effect of being able to return to its proper state through adjustment.

As described above, according to the present invention, since the bearing is pressed against the groove surface by a member such as a spring, (a) uneven load during zoom operation can be eliminated.

(b) Reduction of noise during zoom operation.

(c) Since the clearance between the groove and the bearing can be kept small, image blurring and image blurring can be prevented during zoom operations.

2) Since the surface precision of the groove and the groove can be relaxed, manufacturing becomes easier.

There are other effects.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the groove cam portion of the zoom lens. An explanatory diagram of the flow side. 1...Do not remove the bearing 2...Bearing 3...Moving ring 4...Fixed ring 5... spanner 6...Bearing shaft 7...Moved object 8--Materials 9...8 sticks 10...Push screw 11... Wedge Applicant: Canon Co., Ltd. Sorting map

Claims (1)

[Claims] (0) A plurality of bearings are inserted into one groove coaxially with the bearing shaft, and each bearing contacts only one side of the groove, and the bearings are in contact with only one side of the groove, and each bearing is in contact with only one side of the groove. The grooved cam mechanism is characterized in that the bearing shaft is provided with a member that contacts at least one bearing and presses at least one bearing among the plurality of bearings in the direction of the groove surface of the groove. 2) The grooved cam mechanism according to claim 1, wherein the member is constituted by a spring, a plate spring, or an elastic member. (3) A force that presses the member in the direction of the groove surface of the groove is applied. Claim 1 characterized in that an adjusting means for adjusting is provided.
Groove cam mechanism described in section.