JPH11141623A - Gear transmission mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a backlash in a narrow space. SOLUTION: A first gear 22 of a pinion 20 is engaged with the inner tooth 12 of a large gear 10. The end part 26 on the first gear 22 side of a rotation shaft 27 of the pinion 20 is inserted into a long hole 32, slenderly formed in a direction, orthogonal to the shaft, for nearly connecting the respective rotation centers of the large gear 10 and the pinion 20, and the first gear 22 side is made free in oscillation to pivotally support the rotation shaft 27. A spring member 40 is arranged along the rotation shaft 27 of the pinion 20, and the first gear 22 side of the rotation shaft 27 is energized to the engaging portion side between the inner tooth 12 and the first gear 22, thereby eliminating a backlash between the inner tooth 12 and the first gear 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gear transmission mechanism, and more particularly, to a gear transmission mechanism capable of transmitting rotation without backlash.

[0002]

2. Description of the Related Art Heretofore, the operational feeling has sometimes been a problem in the power focus of a photographing lens, and a major factor is a backlash of a gear train interlocking from an operation ring to a switch section. In order to eliminate such backlash, for example, one of the gears and its rotating shaft are independently supported by a base, and the base is biased or tilted, thereby biasing or tilting one gear toward the other gear. It is proposed to lean.

However, if one of the gears is moved integrally with the base as described above, the overall configuration becomes large, and thus cannot be adopted when there is only a narrow space.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a gear transmission mechanism which can eliminate backlash of a gear pair in a small space.

[0005]

In order to solve the above technical problems, the present invention provides a gear transmission mechanism having the following configuration.

The gear transmission mechanism includes a pair of gears that mesh with each other. One of the pair of gears is fixed to the other end of a rotating shaft having one end pivotally connected and the other end swingable in a direction perpendicular to an axis substantially connecting the rotation centers of the pair of gears. There is provided urging means for urging the other end of the rotating shaft to mesh the pair of gears.

In the above structure, the urging means urges the other end of the rotary shaft to which one of the gears is fixed, toward the meshing portion of the pair of gears. As a result, the teeth of one of the gears bite into the teeth of the other gear close to each other, so that backlash can be eliminated. Since the urging means only needs to urge the rotating shaft, it can be configured in a narrow space.

Therefore, the backlash of the gear pair can be eliminated in a narrow space.

Preferably, the other end of the rotating shaft is inserted into an elongated hole which is elongated in a direction substantially perpendicular to the axis connecting the rotation centers of the pair of gears.

According to the above construction, the other end of the rotating shaft to which one of the gears is fixed is guided by the elongated hole in a direction substantially perpendicular to the axis connecting the rotation centers of the pair of gears, and swings only in that direction. Move. Therefore, even with a simple urging means, the rotating shaft can be urged in an appropriate direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gear transmission mechanism according to each embodiment of the present invention shown in FIGS. 1 to 3 will be described below in detail.

First, the gear transmission mechanism of the first embodiment will be described. As shown in the main part perspective view of FIG. 1 and the main part sectional view of FIG. 2, the gear transmission mechanism includes a large gear 10 having internal teeth 12, a first gear 22 and a second gear 24 having external teeth. A pinion 20 fixed to the rotating shaft 27;
Fixing members 30, 6 for supporting the rotation shaft 27 of the pinion 20
0 and a spring member 40.

The internal teeth 12 of the large gear 10 mesh with the first gear 22 of the pinion 20. Second gear 24 of pinion 20
Meshes with a gear (not shown). The pinion 20 is configured such that both ends 26 and 28 of the rotating shaft 27 are elongated holes 32 of the fixing member 30.
And the round hole 62 of the fixing member 60, and the end 26 of the pinion 30 on the first gear 24 side is swingable.

More specifically, the elongated hole 32 of the fixing member 30 is provided on the first gear 22 side of the pinion 20, and the large gear 1
It is formed to be elongated in the direction perpendicular to the axis connecting the rotation center of the pinion 20 and the pinion 20. The width of the elongated hole 32 is substantially equal to the outer diameter of one end 26 of the rotation shaft 27 of the pinion 20 on the first gear 22 side. The end 26 of the rotation shaft 27 of the pinion 20 on the first gear 22 side is inserted into the elongated hole 32.

The round hole 62 of the fixing member 60 is
Of the pinion 2
0 is substantially equal to the outer diameter of the end 28 of the rotating shaft 27 on the second gear 24 side. The end 27 of the rotation shaft 27 of the pinion 20 on the second gear 24 side is inserted into the round hole 62.

The spring member 40 is connected to the rotation shaft 2 of the pinion 20.
7, the portion of the rotary shaft 27 near the first gear 22 is connected to the internal gear 12 of the large gear 10 and the first gear 22 of the pinion 20.
It is urged toward the meshing portion with the gear 22. Thereby, the rotation shaft 27 of the pinion 20 is moved to the end 26 on the first gear 22 side.
Moves along the long hole 32 of the fixing member 30 in a direction in which the first gear 22 approaches the internal teeth 12 of the large gear 10. As a result, the first gear 22 bites into the internal teeth 12 of the large gear 10 and the backlash between the first gear 22 and the internal teeth 12 is eliminated. The spring member 40 need only urge the rotation shaft 27 of the pinion 20 instead of urge the entire gear support unit including the base, and therefore can be arranged in a narrow space.

Therefore, the gear transmission mechanism can eliminate backlash in a narrow space. Also,
With a simple configuration, backlash can be eliminated.

Preferably, the elongated hole 32 is formed such that the first gear 22 and the internal teeth 12 mesh with each other even when the first gear 22 is farthest from the internal teeth 12, so that gear jumping occurs. Not to be.

Next, a gear transmission mechanism according to a second embodiment will be described with reference to a sectional view of a main part of FIG. This gear transmission mechanism is configured substantially similarly to the first embodiment.
The same reference numerals are given to the same components with the suffix “a” added thereto.

The gear transmission mechanism includes a transmission gear 50 in addition to the large gear 10a, the pinion 20a, and the fixing members 30a and 60a.

The transmission gear 50 has a third gear 5
2 is fixed. The third gear 52 includes a pinion 20a.
With the second gear 24a. The rotation shaft 54 is supported by a long hole 64 provided in the fixed member 60a. The elongated hole 64 is formed to be elongated along a direction substantially perpendicular to the axis connecting the rotation centers of the pinion 20a and the transmission gear 50.

As shown by an arrow 82, the third gear 52
It is configured to be urged toward the second gear 24 by a spring force. The rotation shaft 27a of the pinion 20a is biased toward the internal teeth 12a as shown by an arrow 80.

Therefore, for a plurality of gear pairs, a mechanism for reducing the distance between the shafts by the elongated hole and the spring force can be applied to eliminate backlash between the respective gears.

It should be noted that the present invention is not limited to the above embodiment, but can be implemented in various other modes.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a gear transmission mechanism according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the gear transmission mechanism of FIG. 1;

FIG. 3 is a sectional view of a main part of a gear transmission mechanism according to a second embodiment of the present invention.

[Explanation of symbols]

 10, 10a Large gear 12, 12a Internal teeth 20, 20a Pinion 22, 22a First gear 24, 24a Second gear 26, 26a End 27, 27a Rotating shaft 28, 28a End 30, 30a Fixing member 32, 32a Long Hole 40 Spring seat 50 Transmission gear 52 Third gear 54 Rotating shaft 60, 60a Fixing member 62, 62a Round hole 64 Long hole 80, 82 Arrow

Claims (2)

[Claims] 1. A gear transmission mechanism in which a pair of gears mesh with each other, wherein one of said pair of gears is swingable in a direction perpendicular to an axis connecting one end of the pair of gears and the other end substantially connecting the rotation centers of said pair of gears. A gear transmission mechanism, comprising: urging means fixed to the other end of the rotating shaft to urge the other end of the rotating shaft to mesh the pair of gears. 2. The device according to claim 1, wherein the other end of the rotating shaft is inserted into an elongated hole formed substantially in a direction perpendicular to the axis connecting the rotation centers of the pair of gears. Gear transmission mechanism.