JP3438540B2 - Gear coupling mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear coupling mechanism which constitutes a drive transmission system such as a zoom lens feeding mechanism such as a still camera and a video camera, and other optical system driving mechanism.

[0002]

2. Description of the Related Art With the recent advances in downsizing and high functionality of cameras, for example, in a zoom camera equipped with a lens feeding mechanism using gears, it is possible to effectively use the internal space of the zoom lens barrel or camera body. This is important for downsizing, and for that reason, attempts have been made to reduce the number of gears in the gear arrangement in the gear coupling mechanism that constitutes the lens feeding mechanism and to save space by high-density arrangement.

That is, in the lens feeding mechanism in a zoom camera, a long gear having a small diameter but a large tooth width is provided in a part of a fixed barrel, and a gear is provided between the long gear and a driving motor provided inside the camera. It is known that they are connected in series and the rotation of a drive motor is transmitted to a rotary cylinder arranged in a fixed cylinder at a required reduction ratio.

FIG. 7 shows a conventional example of a gear coupling mechanism used in the zoom lens feeding mechanism as described above. The gear coupling mechanism shown in this figure is used for the fixed barrel 1 of the zoom lens barrel.
And the gear case 5 provided in the camera.

A gear base plate 6 forming the bottom of the gear case 5.
There are three gear support shafts 7, 8, 19 for convenience of the first to third gears.
Are erected integrally. Of these, the first gear support shaft 7 has an input gear 1 connected to a motor driving gear (not shown).
The first and second intermediate gears 13 are rotatably supported so as to have a common center of rotation. A first intermediate gear 12 and a third intermediate gear 14 are rotatably supported on the second gear support shaft 5 so as to have a common rotation center. Further, a connection gear 20 is rotatably supported on the third gear support shaft 19.

A large diameter lens feeding gear (not shown) for transmitting the motor driving force to the zoom lens feeding mechanism is provided on the outer circumference of the rotary barrel (not shown), while the fixed barrel 1 is provided. The opening 16 and the bracket 17 are provided, and the output gear 2 connected to the lens feeding gear is rotatably mounted on the bracket 17 so as to face the opening 16. The output gear 2 is formed of a long gear having a large tooth width because it is necessary to maintain the connected state at all times even if the rotary cylinder is extended in the optical axis direction.

Input gear 11 and first and second intermediate gears 1
2 and 13 are large gear portions 11a, 12a, 13a, respectively.
And small gear portions 11b, 12b, 13b are integrally formed coaxially, and are configured by gear parts having substantially the same size and shape. Also, the third intermediate gear 14 is the first intermediate gear 1
The second large gear portion 12a is composed of an idle gear having the same diameter.

The large gear portion 11a of the input gear 11 is linked to the driving gear of the motor directly or through a gear train, and the small gear portion 11b of the input gear 11 is connected to the large gear of the first intermediate gear 12. The first intermediate gear 1 connected to the portion 12a.
The second small gear portion 12b is the large gear portion 13 of the second intermediate gear 13.
a and the small gear portion 13b of the second intermediate gear 13 is the third
It is connected to each of the intermediate gears 14. Further, the third intermediate gear 14 is connected to the connection gear 20, and the connection gear 20 is connected to the output gear 2 on the fixed cylinder 1 side,
The required reduction ratio is achieved.

That is, the gear coupling mechanism of the above conventional example is
Three intermediate gears 12, 1 between the input gear 11 and the output gear 2
A gear reduction mechanism for reducing the speed in the order of motor driving gear → input gear 11 → first intermediate gear 12 → second intermediate gear 13 → third intermediate gear 14 is configured with 3, 14, 20 interposed.

[0010]

However, like the gear coupling mechanism of the above-mentioned conventional example, the first intermediate gear 12 and the third intermediate gear 12 are
The intermediate gear 14 is coaxial, and the tip gear circle diameters of the large gear portion 12a of the first intermediate gear 12 and the third intermediate gear 14 are approximately the same, and the output gear 2 is When the third intermediate gears 12 and 14 are configured by a long gear having a tooth width equal to or larger than the height in the rotation axis direction, even if the third intermediate gear 14 and the output gear 2 are directly connected, the first intermediate gear Direct coupling is impossible because the tooth tips of the large gear portion 12a of 12 interfere with the output gear 2.

For this reason, the connecting gear 20 which does not necessarily contribute to the achievement of the reduction ratio must be interposed between the both 14, 13, resulting in an increase in the number of gears and for accommodating the gear train. It also becomes impossible to reduce the space.

Therefore, in order to realize a gear connecting mechanism in which the connecting gear 20 is omitted, for example, in the conventional gear connecting mechanism shown in FIG. 8, the input gear 11 and the second intermediate gear 13 are provided on the first gear support shaft 7, In addition, the first intermediate gear 12 and the third intermediate gear 1
4 is coaxially mounted on the second gear support shaft 8 without changing the configuration of the tip gear circle diameter of the large gear portion 12a of the first intermediate gear 12 to be smaller than the tooth bottom circle diameter of the third intermediate gear 14. Therefore, even if the third intermediate gear 14 is directly connected to the output gear 2, the large gear portion 1 of the first intermediate gear 12
2a is designed not to interfere with the output gear 2 which is a long gear.

However, as described above, the first intermediate gear 1
When the second and third intermediate gears 14 are coaxial, and the tip circle diameter of the large gear portion 12a of the first intermediate gear 12 is smaller than the root circle diameter of the third intermediate gear 14, the large gear of the first intermediate gear 12 Part 12a
The diameter of the small gear portion 11b of the input gear 11 must be increased by the amount corresponding to the reduction of the diameter of the input gear 11. As a result, the reduction gear ratio of the first stage cannot be sufficiently obtained, which in turn reduces the speed of the entire mechanism. However, there is a problem that the degree of freedom in design is greatly limited, such as being unable to sufficiently achieve the above.

The present invention has been made in view of the above problems, and, for example, in a gear coupling mechanism incorporated in a zoom lens feeding mechanism or the like, the number of gears constituting the mechanism is reduced, and the gear train can be installed in a small space. The purpose is to realize.

[0015]

To achieve the above object, in the gear coupling mechanism of the present invention, a first gear and a single or a plurality of second gears stacked in the direction of the rotation axis of the first gear are provided.
A gear, said first and said 1 has a rotational axis parallel to the rotation axis of the second gear, third gear having a rotational axis direction of the stack height above the tooth width of the second gear, the first Connected with 2 gears
In a gear coupling mechanism including a fourth gear, the center of rotation of the second gear is at least the tip of the second gear with respect to the center of rotation of the first gear. amount that does not interfere by simply set to a position displaced in a direction away from the third gear, in unconsolidated and the third gear is the second gear, and configured to connect only to the first gear, The first gear is the third gear and the fourth gear.
To function as an idle gear that is commonly connected to
I am.

In the above structure, the center of rotation of the second gear is the first
Since the gear is displaced toward the side away from the position of the third gear with respect to the rotation center of the gear, a gap is created between the tooth tips of the second gear and the third gear, and as a result, the conventionally required connection gear is required. It is possible to directly connect the first gear to the third gear, which is a long gear, without interposing the first gear and without reducing the diameter of the second gear.

In the above structure, the first gear connected to the third gear is rotatable in the rotation axis direction by the locking means provided adjacent to the rotation axes of the first gear and the second gear. May be coupled to the rotary shaft in a state in which the movement of the is restricted.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a gear coupling mechanism according to the present embodiment, and FIG. 1 shows the configuration of a gear train.
Figure 2 shows the combined state of the zoom lens barrel and the gear coupling mechanism.
FIG. 3 is a diagram showing an attachment state of an output gear as a third gear to a fixed cylinder, and FIG. 4 is a diagram showing an arrangement state of a first intermediate gear as a second gear, a third intermediate gear as a first gear, and an output gear. Reference numeral 5 shows a mounting structure of the third intermediate gear to the gear base plate, and FIG. 6 shows a main portion thereof. In these figures,
The same reference numerals are given to the portions having the same configurations and operations as those of the conventional example shown in FIGS. 7 and 8.

The gear connecting mechanism of the present embodiment constitutes a speed reducing means in the lens feeding mechanism of the zoom camera, and it is essential that a part of the fixed barrel 1 of the zoom lens barrel has a tooth width of a small diameter. Is provided with an output gear 2 formed of a long gear, and the output gear 2 and a drive motor 3 provided inside the camera.
Are connected by a gear train, and the rotation of the drive motor 3 is transmitted to the rotary cylinder 4 arranged in the fixed cylinder 1 at a required reduction ratio.

That is, in FIGS. 1 and 2, reference numeral 5 is a gear case provided in the camera, and a gear connecting mechanism is incorporated between the gear case 5 and the fixed barrel 1. A gear base plate 6 forming the bottom of the gear case 5 is integrally provided with first and second gear support shafts 7 and 8 as rotating shafts.

Of these, an input gear 11 connected to a first gear support shaft 7 via a drive gear 9 of a motor 3 and a gear train 10.
Also, the second intermediate gear 13 as the fourth gear has a common center of rotation, and is rotatably supported in a state of being vertically stacked in two stages in the rotation axis direction. On the other hand, the second gear support shaft 5
Is an eccentric shaft, and is a first intermediate gear 12 as a second gear.
Also, a third intermediate gear 14 as a first gear is rotatably supported in a state of being vertically stacked in two stages in the rotation axis direction.

As shown in FIG. 3, on the outer circumference of the rotary cylinder 4,
A large-diameter lens feeding gear 15 for transmitting the motor driving force is provided to the zoom lens feeding mechanism. Also,
The fixed cylinder 1 is provided with an opening 16, and brackets 17 are provided on both sides of the opening 16. The output gear 2 connected to the lens feeding gear 15 is rotatably mounted on the bracket 17.

Input gear 11 and first and second intermediate gears 1
Reference numerals 2 and 13 respectively have large gear portions 11a, 12a, 13a and small gear portions 11b, 12b, 13b integrally formed coaxially, and are gear parts. The third intermediate gear 14 is composed of an idle gear.

The large gear portion 11a of the input gear 11 is linked to the driving gear 9 of the motor 3 through the gear train 10, and the small gear portion 11b of the input gear 11 is larger than the first intermediate gear 12. The first intermediate gear 12 is connected to the gear portion 12a.
The small gear portion 12b of the second intermediate gear 13 is the large gear portion 13a of the second intermediate gear 13.
Similarly, the small gear portion 13b of the second intermediate gear 13 is connected to the third intermediate gear 14, respectively. Further, the third intermediate gear 14 is connected to the output gear 2 on the fixed cylinder 1 side, thereby achieving the required reduction ratio.

In such a structure, the output gear 2
Is formed by a long gear having a large tooth width because it is necessary to always maintain the connection state with the lens feeding gear 15 even when the rotary cylinder 4 is extended in the optical axis direction. Specifically, the output gear 2 is a rotary shaft 2a parallel to the first and second gear support shafts 7 and 8.
And has a tooth width equal to or larger than the stacking height of the first intermediate gear 12 and the third intermediate gear 14 in the axial direction.

Further, with respect to the rotation center of the third intermediate gear 14 which connects the output gear 2, the rotation center of the first intermediate gear 12
A tooth tip of at least the first intermediate gear 12 and the output gear 2
Is set to a position displaced in a direction away from the output gear 2 by an amount that does not interfere with the tooth tip of the output gear 2. As a result, the output gear 2 is not connected to the first intermediate gear 12 and the third intermediate gear 14
It is configured to connect only to.

In such a structure, three stages of intermediate gears 12, 13, and 14 are interposed between the input gear 11 and the output gear 2, and the motor driving gear 9 → gear train 10 → input gear 11 → first intermediate gear. 12 → second intermediate gear 13 → third intermediate gear 14
→ Works with output gear 2. At this time, as shown in FIG. 4, the center of rotation of the first intermediate gear 12 is
Since it is deviated to the opposite side to the output gear 2 with respect to the center of rotation of No. 1, a gap is formed between the tooth tips of the first intermediate gear 12 and the output gear 2, so that between the output gear 2 and the third intermediate gear 14. Directly without interposing the connecting gear 20 as in the conventional example,
The third intermediate gear 14 and the output gear 2 can be meshed with each other.

Further, as is apparent from the above structure, a plurality of gears stacked on a common support shaft as in this embodiment is regarded as one unit, and a plurality of these gears are arranged in parallel and alternately connected. In the gear train configuration of some forms, the third intermediate gear 1
4 functions as an idle gear commonly connected to the second intermediate gear 13 and the output gear 2.

That is, an idle gear is interposed between the gear at the end of the gear train and the long gear (output gear) which is the main power transmission destination, and the shaft center of this idle gear is longer than that of the coaxially stacked gears. By eccentricity to the side away from the gear side, the connection gear that was conventionally required is not required, and
It is possible to realize a small and compact reduction mechanism without limiting the reduction ratio between the other gears that form the gear train. Further, since the third intermediate gear 14 functions as an idle gear, there is an advantage that the gear support shaft 8 on the gear base plate 6 can be thickly secured.

Further, when the third intermediate gear 14 connected to the output gear 2 is mounted on the second gear support shaft 8, the assembling workability is improved by using the locking means as shown in FIGS. 5 and 6. be able to. That is, the elastic force is applied to a position adjacent to the second gear support shaft 8 on the gear base plate 6, specifically, a position facing the notches 8b provided at two positions of the eccentric fitting portion 8a of the second gear support shaft 8. By hooking the hook-shaped engaging claws 18 having a restoring force and fitting the third intermediate gear 14 into the eccentric fitting portion 8a, the third intermediate gear 14 is rotatable by the engaging claws 18 and It is coupled to the second gear support shaft 8 in a state in which the movement in the rotation axis direction is restricted.

In the above embodiment, the third intermediate gear 1
Although the first intermediate gear 12 is the only gear that can be stacked coaxially with the gear 4, the present invention can also be applied to a gear train having a configuration in which a plurality of gears are stacked in multiple stages as needed. The present invention can also be applied to a gear coupling mechanism used for various purposes other than the reduction mechanism of the zoom lens feeding mechanism shown in the above embodiment.

[0032]

As described above, according to the present invention, the third gear is such that the center of rotation of the second gear is at least the tip of the second gear is a long gear with respect to the center of rotation of the first gear. Set it to a position displaced in the direction away from the third gear by the amount that it does not interfere with the tooth tips of the third gear and the fourth gear.
To function as an idle gear that is commonly connected to
Since it has to become a generation of a gap between the tooth tip of the second gear and third gear, as a result, without an intervening conventionally required the connection gear, and without reducing the diameter of the second gear The first gear can be directly connected to the third gear, which is a long gear, so that the space can be used as effectively as possible to secure a large reduction ratio in a small space. In addition, reducing the number of gears reduces the number of parts, which has a great advantage in cost reduction. Furthermore, Gi
The thicker gear shaft of the base plate ensures a higher precision and robustness.
A high gear coupling mechanism can be realized.

According to a second aspect of the present invention, the first gear connected to the third gear is rotatable and rotatable by the locking means provided adjacent to the rotating shafts of the first gear and the second gear. Since it is coupled to the rotary shaft in a state in which the movement in the direction is restricted, the assembling workability can be improved when the first gear is mounted on the rotary shaft.

[0034]

[Brief description of drawings]

FIG. 1 is a sectional view showing a gear coupling mechanism according to an embodiment of the present invention.

FIG. 2 is a plan view showing a coupled state of a zoom lens barrel and a gear coupling mechanism.

FIG. 3 is a perspective view showing a mounting state of a third gear to a fixed barrel.

FIG. 4 is a plan view showing an arrangement state of first to third gears.

FIG. 5 is a plan view showing a modification of the mounting structure of the first gear to the gear base plate.

FIG. 6 is an enlarged perspective view showing a main part thereof.

FIG. 7 is a sectional view showing a conventional example.

FIG. 8 is a sectional view showing a conventional improvement example.

[Explanation of symbols]

2 output gear (3rd gear) 2a rotating shaft 6 gear base plate 7 1st gear support shaft (rotating shaft) 8 2nd gear support shaft (rotating shaft) 8a Eccentric fitting part 11 input gear 12 1st intermediate gear (2nd gear) 13 2nd intermediate gear (4th gear) 14 3rd intermediate gear (1st gear) 18 Engaging claw (locking means)

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B ⁷ /02-7/16 G03B 17/00-17/02 G03B 17/26-17/34 G03B 17/38-17 / 46 F16H 1/00-1/26 F16H 19/00-37 / 16,49 / 00

Claims (2)

(57) [Claims] 1. A first gear, a single or a plurality of second gears stacked in the rotation axis direction of the first gear, and a rotation axis parallel to the rotation axes of the first and second gears. A third gear having a tooth width equal to or larger than the stacking height of the first and second gears in the rotation axis direction, and a fourth gear connected to the second gear.
In the gear coupling mechanism including a gear, the rotation center of the second gear is such that at least the tooth tip of the second gear does not interfere with the tooth tip of the third gear with respect to the rotation center of the first gear. by setting only displaced in a direction away from the third gear position, in a non-consolidated and the third gear is the second gear, and configured to connect only to the first gear, before
The first gear is commonly connected to the third gear and the fourth gear.
A gear coupling mechanism that functions as a coupled idle gear . 2. A first gear connected to a third gear is rotatable and movable in the direction of the rotation axis by a locking means provided adjacent to the rotation axes of the first gear and the second gear. The gear coupling mechanism according to claim 1, wherein the gear coupling mechanism is coupled to a base plate integral with the rotary shaft in a regulated state.