JPS63152767A - Gear and transmission mechanism using it - Google Patents

Abstract

PURPOSE:To prevent occurrence of single-side contact phenomenon by furnishing a curvature like a convex lens in the direction of tooth trace at the flank and the tooth crest. CONSTITUTION:Tooth of this gear has a curvature like a convex lens in the direction of tooth trace (shown by arrow A in the attached illustration) at the flank 20 and tooth crest through rolling process at the time of tooth creation with hob by the use of a gear work created without moving the hob in the tooth trace direction of the gear work. Accordingly the flank 20 and the tooth crest 21 of this gear 22 have a curvature, so that there is no risk of occurrence of single-side contacting phenomenon even though the axis of gear 22 is inclined to either side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gear and a transmission system using the gear, and is designed to prevent the occurrence of so-called uneven contact phenomenon.

(Prior Art) Conventionally, various lens drive devices have been constructed with a separate transmission mechanism consisting of a plurality of gears, as shown in FIG.

That is, the first gear G1 rotationally driven by the motor 1
is meshed with a third gear G3 carved on the outer periphery of the lens barrel 3 in which the lens 2 is housed, via a second gear G2.
By rotating the motor 1, the above! i
The cylinder 3 is rotated.

Further, a male screw (not shown) is carved on the outer periphery of the lens barrel 3, and this male screw meshes with a female screw (not shown) carved on the inner periphery of the housing.

Thereby, by rotating the lens barrel 3 as described above, the lens barrel 3 is moved along with the lens 2 in the optical axis direction.

On the other hand, in the lens driving device as described above, the position of the lens 2 is detected by, for example, a rotary encoder 4, and various autofocus devices are configured to move the motor 1 to a certain position according to this detected position. By rotating the lens 2 by a fixed amount, the lens 2 is moved to the just-focus position.

The rotary encoder 4 rotates the #An3 by meshing the fifth gear Gs attached to the rotating shaft of the rotary encoder 4 with the third gear G3 via the fourth gear G4. A signal corresponding to the amount, that is, the position of the lens 2 is output.

By the way, in general, in a transmission mechanism consisting of multiple gears as described above, in order to obtain smooth rotation of each gear even when the distance between the shafts fluctuates due to temperature changes, for example, Backlash is provided between each gear.

For this reason, there is a problem in that, for example, when the motor 1 is started or reversed, the teeth of each gear collide with each other and generate loud mechanical noise.

Moreover, as shown in FIG. 11, each of the above gears G! ~ Gs tooth surface 5 and tooth tip surface 6 are generally in the direction of the tooth trace (6 directions of arrows in the figure)
is parallel to

For this reason, if the axes of the gears 01 to G5 are not parallel, a so-called uneven tooth contact phenomenon will occur, and the edge portions of the teeth will come into contact with each other, resulting in louder mechanical noise.

In particular, it is an object of the present invention to provide a gear that can eliminate the occurrence of the uneven contact phenomenon, and a transmission mechanism using this gear.

Invention・And this book-a- is the first to achieve this purpose.
As shown in the figure, when creating a bob, the tooth surface 20 and the tooth tip surface 21 are rolled by using the created work gear without moving the bob in the tooth trace direction of the work gear. The present invention provides a gear 22 characterized by having a convex lens-like curvature in the tooth trace direction (in the six directions of arrows in the figure).

(Function) In the gear 22 configured as described above, the tooth surface 220 has a curvature, and the tooth tip surface 2 of this gear 4'+
Since gear 1 has a curvature, even if the shaft of gear 22 is tilted in either direction as shown in FIG. 2 or 3, no uneven contact will occur.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail using FIGS. 1 to 9.

In this embodiment, a gear 22 according to the present invention and a transmission mechanism using this gear 22 are applied to a lens driving device a.

The lens driving device according to this embodiment is as shown in FIG.
A lens barrel 13 incorporating a focusing lens 11 is arranged so as to be slidable and rotatable in the optical axis direction within the housing 14, and a lens barrel 13 is screwed onto the outer peripheral surface of the lens barrel 13. A male thread 15 is screwed into a female thread 16 carved on the inner peripheral surface of the housing 14, and the lens barrel 13
By rotating this lens barrel 13, the above-mentioned lens 1
1 in the optical axis direction within the housing 14.

In addition, the housing 14 is provided with a bracket 1 as shown in FIG.
A pulse motor 10 is attached via 7, and the first gear G1 is rotated by this pulse motor 10.
is a third gear G9 carved on the outer peripheral surface of the lens barrel 13.
The second gear G2 meshes with the second gear G2 through the opening 18.

Thereby, the lens barrel 13 is rotated by rotationally driving the pulse motor 10.

Further, the fourth gear G4 provided coaxially with the second gear G2 is connected to the rotary encoder via a fifth gear G5 and a sixth gear G6 provided coaxially with the fifth gear G5. 7th gear G7 provided coaxially with the rotation shaft of No. 12
It meshes with the

Thereby, an encoder output corresponding to the amount of rotation of the lens barrel 13 is outputted as position information of the lens 11.

Further, each tooth of the first to seventh gears 01 to G7 in the lens driving device as described above has a shape as shown in FIG.

That is, the teeth 23 of the gear 22 shown in FIG. 1 have a tooth surface 20 having a convex lens-like curvature in the tooth trace direction, and
The tooth tip surface 21 also has a convex lens-like curvature in the direction of the tooth trace.

Since it has such a shape, each gear 22
Even if the teeth 23 mesh with each other in a state of being inclined to some extent as shown in FIG. 2 or FIG. 3, the uneven contact phenomenon does not occur because they always make point contact with each other midway in the tooth trace direction.

Further, the gear 22 having the above-mentioned shape is shown in FIGS. 6 to 9.
It is manufactured as shown in the figure.

That is, first, as shown in FIGS. 6 and 7, the cut gear 24 used when rolling the gear 22 is in a state where the cut gear 24 and the bob 25 are meshed together when cutting the bob. These gear 24 and bob 25 are rotated in the direction of the arrow in the figure.

As a result, the tooth tip surface 26 of the gear to be cut 24 is formed to have a concave lens-like curvature in the direction of the tooth trace, as shown in FIG.

Next, with the gear 24 to be cut and the raw material 22- of the gear 22 brought into pressure contact as shown in FIGS. 8 and 9, the gear 24 and the raw material 22' are rotated in the direction of the arrow in the figure. let

As a result, the gear 22 having the teeth 23 shaped as shown in FIG. 1 is rolled.

Here, conventionally, when the tooth surface 21 was to have a curvature, each tooth 23 was processed into a predetermined shape by grinding with a special machine.

For this reason, it has conventionally taken an extremely long time to manufacture this type of gear, and precision machining of small gears has been inappropriate.

On the other hand, when manufacturing as described above, a sophisticated gear can be manufactured in an extremely short time regardless of the size of the gear.

By using the gear 22 shown in FIG. 1, which has such high processing precision, it is possible to reduce the precision with respect to the parallelism of the shafts, especially in small precision instruments such as lens drive devices.

Note that the transmission mechanism according to the present invention is of course not limited to that used in the lens drive V device as described above, and the gear according to the present invention may mesh with a normal gear.

(Kinuta Effect) As is clear from the above explanation, the present invention prevents the occurrence of so-called uneven contact phenomenon by providing a convex lens-like curvature in the tooth trace direction of the tooth surface and tooth tip surface of the gear teeth. can do.

In addition, the above-mentioned gear according to the present invention is particularly advantageous because it is made by rolling using the created work gear without moving the hob in the direction of the teeth of the work gear during hob cutting. It can be easily manufactured and
Even small gears can be manufactured with precision.

Therefore, by using such a gear in various transmission mechanisms, especially in small precision equipment, it is possible to reduce the machining accuracy of shaft installation of this transmission mechanism, improve productivity,
Cost reduction can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of essential parts showing an embodiment of a gear according to the present invention;
2 and 3 are diagrams each showing the meshing state of the gear teeth shown in FIG. 1, FIG. 4 is a partially cutaway vertical side view showing an embodiment of the transmission mechanism according to the present invention, and FIG. 6 and 7 are diagrams schematically showing the manufacturing process of the gear shown in FIG. 1, respectively showing the relationship between the hob and the gear to be cut, and FIG. and FIG. 9 are diagrams showing the relationship between the gear to be cut and the gear according to the present invention, FIG. 10 is a diagram schematically showing a transmission mechanism in a conventional lens drive device, and FIG. 11 is a diagram showing a conventional general transmission mechanism. It is a figure which shows the meshing state of the teeth of a gear. 20... Tooth surface, 21... Tooth tip surface, 22... Gear,
24...Work gear, 25...Hob. Leaf lΔ Kayayo Figure 1 Evening view

Claims (2)

[Claims] (1) When creating a bob, rolling is performed using the created work gear without moving this bob in the direction of the tooth trace of the tooth surface and tooth tip. A gear having a convex lens-like curvature. (2) A transmission mechanism characterized by comprising a plurality of gears having convex lens-like curvatures in the direction of tooth traces on tooth surfaces and tooth tips.