JP2004191434A - Reduction gear unit, camera using the unit and method of assembling the unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a very reliable reduction gear unit capable of eliminating adverse influence of grease or the like with which a gear is filled by improving the resolution for detecting pulses for counting the revolving speed of a motor with a simple structure, a reduction gear unit assembling method and a zoom device for camera using the reduction gear unit. <P>SOLUTION: Gears 30, 31, 32, 33 and 35 are assembled in a gear box 4. An impeller 21 and a pinion 23 are attached on the output shaft of a motor 2, and the pinion 23 on the output shaft is meshed with the input gear of the gear box, so that the motor 2 is fixed in the gear box. The impeller 21 is housed in space partitioned off from the pinion housing part of the gear box 4. A sensor 27 for detecting the rotation of the impeller 21 is attached and the gear box is hermetically sealed with a cover. Thus, a gear train is easily formed and the sensor can be prevented from being adversely influenced by the scattering of the grease. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reduction gear unit that reduces a motor output by a reduction gear train and transmits the reduced output to a subsequent stage, a camera using the reduction gear unit, and an assembling method of the reduction gear unit.
[0002]
[Prior art]
For example, as described in Patent Document 1, a zoom mechanism of a silver halide camera or a digital camera uses a drive mechanism for performing a zooming drive. This drive mechanism is configured such that the rotation of the motor is reduced by a reduction gear train and transmitted to the zoom mechanism, and some lenses move forward and backward.
In such a zooming operation, an impeller is attached to one of the rotating shafts of the drive mechanism to detect the number of rotations of the motor, but the number of rotations of the motor is accurately detected to bring the lens to the zoom position accurately. Need to be
In order to accurately detect the number of rotations of the motor, an impeller must be provided as close to the motor output shaft as possible to extract a large number of pulses per rotation of the motor.
[Patent Document 1]
JP-A-10-62852
[Problems to be solved by the invention]
However, in the conventional reduction gear train, since a motor in which a gear is attached to an output shaft is first arranged on a substrate and then the gear is assembled, it takes time and effort to replace the work, or only the motor can be replaced. There was a problem that could not be done.
In addition, since grease is applied to the input side (upstream side) of the reduction gear group for soundproofing and efficiency measures, there is a problem that the grease scatters on the impeller and the photosensor, and the performance is reduced. Therefore, if an impeller is provided on the output side of the reduction gear group to ensure reliability, a problem occurs in that the number of pulses is reduced and the resolution of the motor speed encoder is reduced. In order to solve this problem, an amplification system may be provided. However, there is a problem that the number of components newly increases.
[0004]
An object of the present invention is to facilitate the assembly of the reduction gear unit and to replace the motor, and to improve the resolution of the pulse count for detecting the motor rotation speed with a simple structure, and to reduce scattering of grease filling the gear. It is an object of the present invention to provide a highly reliable reduction gear unit capable of eliminating adverse effects, a method of assembling the reduction gear unit, and a camera using the reduction gear unit.
[0005]
[Means for Solving the Problems]
To achieve the above object, a first aspect of the present invention is a motor having a gear and a rotational speed detecting means formed on an output shaft, a first opening for coupling with the gear of the motor, and a deceleration driving force. A housing for accommodating a plurality of gears including an input gear near the first opening and an output gear near the second opening, and a housing in the first opening. A gear box having a dedicated space for accommodating the rotational speed detection means separated therefrom, wherein the output shaft is inserted from the first opening and the gear of the motor is connected to the input gear. At the time of engagement, the rotational speed detecting means is housed in the space.
According to a second aspect of the present invention, in the first aspect, a motor fixing member is provided extending from an outer shell of the motor, and the motor fixing member is fixed to the gear box.
According to a third aspect of the present invention, in the first aspect, the rotation speed detecting means has a light emitting unit and a light receiving unit, and the rotation of the impeller impeller rotates between the light emitting unit and the light receiving unit. The speed can be detected, and the speed is detected above the first opening.
A fourth aspect of the present invention is characterized in that, in the third aspect, the rotational speed detection means is configured to be disposed in the gear box.
A fifth aspect of the present invention is characterized in that the first opening is a substantially U-shaped notch, a step is provided in the motor, and the step is fixed by the notch.
In the zoom device for a camera according to the present invention, the output gear is connected to a zoom mechanism of the camera and the zoom operation is performed by the rotational driving force of the motor.
A method of assembling a reduction gear unit according to the present invention includes a motor having a gear and a rotational speed detecting means attached to an output shaft, a first opening for coupling with the gear of the motor, and a second opening for outputting a reduction driving force. A gear box having a housing for accommodating a plurality of gears including two openings and an input gear near the first opening, and an output gear near the second opening; and a housing for the gear box. Attaching the gear to the input shaft, inserting the output shaft through the first opening to engage the gear of the motor with the input gear, attaching the motor fixing member to the gear box, and attaching the motor to the gear box. A fixing step; a step of disposing a rotational speed detecting means above the rotational speed detecting means and the first opening; and a step of covering the gear box with a cover. And wherein the door.
[0006]
[Action]
According to the first aspect, by assembling the motor last, the gear train can be easily assembled, and the motor can be replaced. Further, since the rotational speed detecting means is accommodated in the space formed exclusively, the resolution of the encoder is improved, and the grease scattering of the gear can be prevented.
According to the second aspect, the motor can be easily fixed.
According to the third aspect, the rotation speed detecting means can prevent the grease from being scattered, and can effectively use the dead space.
According to the fourth aspect, the rotation speed detecting means can be easily and reliably provided.
According to the fifth aspect, since the motor is fixed at three points, the accuracy of the motor fixing is increased.
According to the sixth aspect, the size of the camera can be reduced because the reduction gear unit can be reduced in size.
According to claim 7, since a complicated assembly process is not included, the efficiency of the assembly method can be improved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a camera using a reduction gear unit according to the present invention.
In this figure, a reduction gear unit 1 is connected to a photographic lens frame portion of a camera having a zoom function, and a lens portion that can be moved forward and backward by a moving frame is omitted.
The reduction gear unit 1 is configured by incorporating the motor 2 into the reduction gear mechanism 3, and the final gear 35 of the gear box 4 of the reduction gear mechanism 3 is meshed with a connecting gear 36 incorporated in the photographing lens frame 7. (See FIG. 5A).
[0008]
The taking lens frame 7 includes a fixed frame 8 and a moving frame 9 fixed to a camera body (not shown). When the rotational driving force is transmitted from the reduction gear unit 1 to the connecting gear 36 for the zoom operation, the moving frame 9 rotates inside the fixed frame 8.
A cam groove 9a is formed in the moving frame 9, and a pin 9b attached to a lens frame (not shown) is fitted in the cam groove 9a. The pin 9b is guided by the cam groove 9a by the rotation of the moving frame 9, and the lens moves forward and backward, thereby performing a zooming operation.
As will be described later, since the output gear of the downsized reduction gear unit 1 of the present invention is connected to the connecting gear 36 in the photographic lens frame 7 to constitute a photographic lens zooming mechanism, the camera can be further miniaturized. Can be realized.
[0009]
FIG. 2 is a view showing an embodiment of the gear box 4 of the reduction gear unit 1 according to the present invention. FIG. 2A is a front perspective view of the gear box, FIG. 2B is a rear view, and FIG. 2C is a rear perspective view. ing.
The gear box 4 is integrally formed of resin, and a ridge 4a is formed on a peripheral edge portion. Reduction gear housings 14, 15 and gear housings 17, 18 are provided inside the jetty 4a, and gear shafts 14a, 15a, 16a, 18a for rotatably mounting the gears are implanted respectively. ing.
The gear box 4 has a notch 11, which is a first opening for coupling the motor shaft, and a notch 10, which is a second opening for connecting the output gear.
An impeller accommodating portion 12 for accommodating an impeller is formed inside the notch 11 for coupling the motor shaft, and a motor pinion accommodating portion 13 for accommodating a gear of the motor shaft is formed inside the notch 11.
[0010]
The motor shaft coupling notch 11 has a U-shape, and motor fixing female screws 4b and 4c are provided so as to sandwich the U-shape. In addition, a positioning protrusion 4d for determining a fixed position of the motor is implanted beside the notch 11 for coupling the motor shaft.
The motor fixing plate 20 for fixing the motor is positioned (shown by a two-dot chain line) as shown in FIG.
The impeller accommodating portion 12 and the motor pinion accommodating portion 13 are separated by half by a wall 12a. The impeller accommodating portion 12 has a U-shape with a semicircular bottom so that the impeller does not contact the surrounding wall when the impeller is accommodated. It has a groove shape. Further, the motor pinion accommodating portion 13 has a space for accommodating the pinion rotatably.
[0011]
FIG. 3 is a perspective view showing a state where a motor is mounted on the gear box, and FIG. 4 is a perspective view showing a state where each gear and a sensor are mounted on the gear box.
As a procedure, each gear is assembled into the gear box 4, and then the motor pinion 23 and the impeller 22 attached to the output shaft 24 of the motor 2 are inserted into the motor pinion accommodating section 13 and the impeller accommodating section 12, and the motor pinion 23 And the motor 2 is attached to the gear box 4. A motor fixing plate 20 is fixed to the front surface of the motor outer shell 21. The motor fixing plate 20 is positioned by the positioning protrusion 4d as described above, and screws are screwed into the motor fixing screws 4a and 4b. Fix it. Reference numeral 24 denotes an output shaft of the motor 2.
As described above, since the motor 2 is assembled after the gears in the gear box 4 are first assembled, the gear box 4 can be easily assembled, the motor 2 can be replaced, and a complicated gear arrangement is possible. It can be reduced in size.
Moreover, by forming the impeller housing portion 12 and forming the impeller housing portion 12 separately from the gear housing portion and the wall 12a, it is possible to prevent the grease of the gear from scattering to the impeller 22.
In this embodiment, the rotating speed detecting means is a propeller-shaped impeller 22 in consideration of the easiness of manufacturing and the reliability of the detection. However, the rotating speed detecting means can be inserted into a motor shaft to be described later to detect the rotating speed. Any shape may be used.
[0012]
In the present embodiment, a step 2a (see FIG. 6) is provided on the distal end side of the motor 2, and the step 2a is supported in a state in which it contacts the three points 11a, 11b, and 11c of the notch 11. The fixed position accuracy of the motor 22 can be improved. The three-point support may be performed on either the notch 11 or the motor fixing plate 20, or may be performed on both.
As shown in the developed view of FIG. 6, the reduction gear group includes a first reduction gear 28 and a third reduction gear 30 rotatably mounted on the shaft 14a, and a second reduction gear 29 and a fourth reduction gear 31 on the shaft 15a. It is mounted to be rotatable. The gear 28a of the first reduction gear 28 is an input gear, and the gear 28b integral with the gear 28a meshes with the gear 29a of the second reduction gear 29. The gear 29 b integral with the gear 29 a meshes with the gear 30 a of the third reduction gear 30. The gear 30 b integral with the gear 30 a meshes with the gear 31 a of the fourth reduction gear 31.
Further, the gear 31b integral with the gear 31a meshes with the gear 32, the gear 32 meshes with the gear 33, and the gear 34 integral with the gear 33 meshes with the gear 35 which is the final gear.
When the gear 35 is incorporated in a camera or the like, the gear 35 meshes with a connecting gear 36 in the photographic lens frame.
After the gears are assembled in the gear box 4, the motor is attached to the gear box 4, so that the gear assembling process is facilitated.
[0013]
Next, the sensor 27 is attached to the gear box 4.
5A and 5B are perspective views showing a mounting structure of the sensor 27 in which the gear box 4 is omitted.
The sensor 27 includes a light emitting unit 27a and a light receiving unit 27b, and is attached to the gear box 4 so that the blades of the impeller 22 are positioned between the light emitting unit 27a and the light receiving unit 27b. Thereafter, the gear box cover 5 is attached to the gear box 4 as shown in FIG. 1, and the inside of the gear box 4 is sealed.
Since the encoder including the sensor 27 and the impeller 22 is housed in a different housing from the gear group in the gear box 4, the grease used for the gear group does not scatter and adhere to the sensor or the impeller. The dead space of the gear box can be used effectively. In particular, since the sensor 27 is provided above, it is hardly affected by grease. In addition, since the sensor 27 is disposed at a position that normally serves as a dead space, it contributes to downsizing. Further, since the encoder is provided on the output shaft of the motor, the number of pulses of the encoder with respect to the motor rotation speed can be increased, and the resolution of the count can be improved.
In this embodiment, as shown in FIGS. 2A, 2C, 3 and 4, it is preferable to form a sensor mounting portion 4e on which the sensor 27 can be arranged above the vicinity of the notch 11 of the gear box 4. By forming the sensor mounting portion 4e, the sensor 27 can be easily and reliably provided. Further, by attaching the gear box cover 5, the sensor 27 is fixed between the sensor mounting portion 4e and the gear box cover 5, and the positional accuracy of the arrangement is improved.
Further, as in the present embodiment, the steps of attaching the gears to the gear box 4, incorporating and fixing the motor 2 and attaching the gear box cover 5 after disposing the sensor 27 make the assembly process simple and efficient. Can be done.
[0014]
【The invention's effect】
As described above, according to the present invention, a pulse for detecting the number of revolutions can be output from the pinion with a simple structure, and the resolution of the encoder can be improved. It is possible to realize a structure that is not affected by the grease applied to the gear. The gear train can be easily assembled, and the motor can be replaced. Also, the assembling process of the reduction gear unit is facilitated.
Furthermore, the motor output shaft with the pulse number counting propeller is fitted into the gear box, and the fixing member of the motor is fixed across the U-shaped notch, so that three-point support can be performed, and the accuracy of the motor fixing position can be secured.
If the speed reduction unit according to the present invention is used for a zoom device of a camera, it can contribute to downsizing of the camera.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a camera zoom device using a reduction gear unit according to the present invention.
FIG. 2A is a perspective view showing an embodiment of a gear box.
FIG. 2B is a rear view of FIG. 2A.
FIG. 2C is a rear perspective view of FIG. 2A.
FIG. 3 is a perspective view showing a state where a motor is attached to a gear box.
FIG. 4 is a perspective view showing a state where each gear and a sensor are attached to a gear box.
FIG. 5A is a perspective view for explaining a sensor mounting structure with a gear box omitted.
FIG. 5B is a perspective view of FIG. 5A as viewed from the back.
FIG. 6 is a sectional view in which a gear is developed.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 reduction gear unit 2 motor 3 reduction mechanism 4 gear box 5 gear box cover 6 connecting gear 7 photographing lens frame 8 fixed frame 9 moving frame 11 notch for coupling motor shaft 12 impeller housing 13 motor pinion housing 14, 15 reduction gear Housings 17, 18 Gear housing 20 Motor fixing plate 22 Impeller 23 Motor pinion 24 Motor output shaft 27 Sensors 28, 29, 30, 31 Reduction gears 32, 33, 34, 35, 36 Gears

Claims (7)

A motor having a gear and a rotational speed detecting means formed on the output shaft,
A plurality of openings including a first opening for coupling with a gear of the motor, a second opening for outputting a reduced driving force, an input gear near the first opening, and an output gear near the second opening. A gear box having a housing portion for housing a gear, and a dedicated space portion for housing the rotational speed detection means separated from the housing portion in the first opening,
When the output shaft is inserted from the first opening and the gear of the motor meshes with the input gear, the rotation speed detecting means is accommodated in the space. The reduction gear unit according to claim 1, wherein a motor fixing member is provided extending from an outer shell of the motor, and the motor fixing member is fixed to the gear box. The rotation speed detecting means has a light emitting unit and a light receiving unit, and the rotation speed can be detected by passing a blade portion of the impeller between the light emitting unit and the light receiving unit, and is provided above the first opening. The reduction gear unit according to claim 1, wherein the reduction gear unit is arranged. 4. The reduction gear unit according to claim 3, wherein said rotational speed detecting means can be arranged in said gear box. The reduction gear unit according to claim 1, wherein the first opening is a substantially U-shaped notch, and a step is provided in the motor, and the step is fixed by the notch. 6. The camera according to claim 1, wherein the output gear is connected to a zoom mechanism of the camera, and a zoom operation is performed by a rotational driving force of the motor. A motor having a gear and a rotational speed detection means attached to an output shaft,
A first opening for coupling with a gear of the motor, a second opening for outputting a reduced driving force, an input gear near the first opening, and an output gear near the second opening; A gear box having an accommodating portion for accommodating a plurality of gears,
Attaching a gear to the housing of the gear box;
Inserting the output shaft from the first opening to mesh the gear of the motor with the input gear;
Attaching the motor fixing member to the gear box and fixing the motor to the gear box;
Disposing a rotational speed detecting means above the rotational speed detecting means and the first opening;
Covering the gear box with a cover,
And a method of assembling the reduction gear unit.

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