JPH1152461A - Planet gear mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely switch the transmission of driving force by a planet gear mechanism. SOLUTION: A planet gear supporting arm 24 supporting first and second planet gears 22 and 23 meshed with a solar gear 21 and freely turnably fitted to the gear 21 is provided with an arm 56. A friction part 56a is formed at the tip of the arm 56. The arm 56 enters a groove 57 of the gear 21 to abut the friction part 56a on the outside wall surface 57a of the groove 57. Then, the friction part 56a and the wall surface 57a are slid when the gear 21 is rotated and thereby, the force in the same direction as the rotating direction of the gear 21 acts on the arm 24. By this force, the gears 22 and 23 revolve in the same direction as the rotating direction of the gear 21 together with the arm 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear mechanism used for a camera film feeder or the like.

[0002]

2. Description of the Related Art A planetary gear mechanism is used as a switching mechanism for switching a gear train to which rotation (driving force) from a motor or the like is transmitted. In this planetary gear mechanism, a sun gear,
The planetary gear includes a planetary gear meshed with the sun gear, and a planetary gear support arm that supports the planetary gear so as to revolve around the sun gear and also supports the planetary gear so as to rotate. When the rotation direction of the sun gear is switched by rotation transmitted from a motor or the like, the planetary gear revolves in the same direction as the sun gear, so that the gear to mesh with changes. The planetary gears stop rotating at the positions of the meshed gears and rotate, thereby transmitting rotation from a motor or the like to a gear train connected to the meshed gears.

By the way, in order to reliably switch the gear train for transmitting rotation by using a planetary gear mechanism, it is necessary to apply a load to the planetary gear so that the planetary gear is unlikely to rotate on its own. . If the load is not appropriate, for example, if the load is small, the planetary gears will only rotate on the spot and will not revolve around the sun gear, so switching will not be performed, and if the load is too large, switching will not be performed. Although the rotation is surely performed, the rotation of the planetary gear becomes heavy due to the load, and a large load is applied to a driving source such as a motor.

For this purpose, a pressing member for pressing a planetary gear made of a metal leaf spring, a resin spring, or the like is usually provided integrally or separately as a planetary gear supporting arm,
In some cases, an appropriate load is applied to the planetary gear to make it difficult to rotate. Further, there is known a planetary gear in which an elastic arm having a spring property is provided at a central portion to obtain a load (Japanese Utility Model Publication No. 7-45069). This real fairness 7-45
According to Japanese Patent No. 069, an elastic arm provided at the center of a planetary gear is pressed against the outer peripheral surface of a rotating shaft (supporting shaft) for rotating the planetary gear of the supporting arm, whereby the rotating shaft and the elastic arm are brought into contact with each other. Load on the planetary gear by the frictional force of
The rotation of the planetary gear is suppressed, and the planetary gear revolves in the same direction as the sun gear.

[0005]

When a load is applied to the planetary gear using a metal leaf spring or a resin spring as described above, the number of parts and the number of assembling steps increase. Was inconvenient. Further, in this case, when adjusting the load applied to the planetary gear, the thickness of the leaf spring and the degree of bending are changed. However, it is easy to remodel the press die with the change. There was a problem that it could not be performed.

On the other hand, if the elastic arm is provided integrally with the planetary gear, the above disadvantages such as an increase in the number of parts and the number of assembling steps can be solved. However, if the diameter of the planetary gear is reduced, the length of the elastic arm is reduced. However, there is a problem in that it is difficult to obtain an appropriate load because the length of the load cannot be sufficiently long. Conversely, if the length of the elastic arm is set to a sufficient length in order to obtain an appropriate load, the diameter of the planetary gear increases, and the size of the planetary gear mechanism increases. Therefore, when a planetary gear mechanism that applies an appropriate load to the planetary gear is incorporated in a camera or the like, a large space is required inside the camera or the like, and there is a problem that the camera becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a planetary gear mechanism capable of reducing the number of parts, facilitating assembly, and reliably switching the transmission of driving force. The purpose is to provide.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a sun gear is formed integrally with a sun gear, and a circumferential wall around the axis of the sun gear and a planetary gear. A friction member formed on the gear support arm and pressed against the wall surface, wherein the planetary gear and the planetary gear support arm are moved by the frictional force generated between the wall surface and the friction member when the sun gear rotates. It revolves.

According to the second aspect of the present invention, the friction member is provided at the distal end of an elastic arm integrally formed with the planetary gear supporting arm, and is pressed against the wall surface by the elastic force of the arm. . According to the third aspect of the present invention, a plurality of friction members are provided, and a plurality of friction members are provided, and these friction members are pressed against a position at which the entire circumference of the wall surface of the sun gear is equally divided. Things.

According to the fourth aspect of the present invention, the planetary gear support arm is provided with a friction member which presses against the sun gear in a radial direction of the sun gear, and when the sun gear rotates, the diameter of the sun gear by the friction member is increased. A frictional force is generated between the friction member and the sun gear by a pressure contact force in a direction, and the planetary gear is revolved by the frictional force.

[0011]

FIG. 2 schematically shows a film feeder for a camera using the planetary gear mechanism of the present invention. At both ends of the camera, a cartridge loading chamber and a film loading chamber are arranged. In the cartridge loading chamber, a spool drive shaft 14 that engages with the spool 13 of the cartridge 12 is arranged, and in the film winding chamber, a winding shaft 15 around which rubber is wound is provided. A motor 16 for rotating the spool drive shaft 14 and the take-up shaft 15 is disposed in the take-up shaft 15. The motor 16 rotates forward (counterclockwise in the drawing) when the film is wound. ), And is reversed when the film is rewound.

The cartridge 12 is currently commercially available.
In the Advanced Photo System, the photo film 12a is completely stored in the cartridge 12 when not in use, and the spool 13 is rotated by the spool drive shaft 14 in the film feeding direction after being loaded into the camera. From 12, the leading end of the photographic film 12 a is sent out to a winding shaft 15 of the camera. Also,
After the photographing, the spool drive shaft 14 rotates the spool 13 in the film rewinding direction, whereby the front end of the photographic film 12a is rewound into the cartridge 12.

The spool drive shaft 14 and the take-up shaft 15
The motor 16 rotates by transmitting the driving force of the motor 16 via a gear train. In this gear train, a motor-side transmission system 17 that transmits the driving force of the motor 16 to another gear train, a spool-side transmission system 18 that transmits the driving force to the spool drive shaft 14,
Winding shaft side transmission system 19 for transmitting a driving force to winding shaft 15
And the planetary gear mechanism 20 of the present invention.

The planetary gear mechanism 20 is provided for switching the transmission system for transmitting the driving force. The planetary gear mechanism 20 includes a sun gear 21, a first planetary gear 22 and a second planetary gear 23 meshed with the sun gear 21, and a planetary gear support arm that supports the first and second planetary gears 22 and 23. 24, the first and second planetary gears 22 and 23 revolve around the sun gear 21 so that the driving force from the motor-side transmission system 17 can be wound up by the spool-side transmission system 18 and the winding shaft when the film is wound up. This is transmitted to both the transmission system 19 and the spool transmission system 18 when the film is rewound. The details of the planetary gear mechanism 20 will be described later.

The motor-side transmission system 17 includes drive gears 31, D1 to D6 gears 32 to 3 connected to the output shaft of the motor 16.
, And the driving force of the motor 16 is
Transmit to 1. D which is the output of the motor side transmission system 17
The six gears 37 mesh with the sun gear 21 to rotate the sun gear 21 counterclockwise when the motor 16 rotates forward, and to rotate the sun gear 21 clockwise when the motor 16 rotates reversely. And rotate. The D1 gear 32 and the D2 gear 33, the D3 gear 34 and the D4 gear 35,
The fifth gear 36 and the D6 gear 37 are two-stage gears integrally formed coaxially.

The spool-side transmission system 18 is a reduction gear train including a clutch built-in gear 38, S1 to S9 gears 39 to 47, and an S10 gear 14a integrally formed on the upper surface of the spool drive shaft 14. . The S5 gear 41 and S6 gear 42, and the S7 gear 43 and S8 gear 44 are two-stage gears, respectively. The motor-side transmission system 17, the winding shaft-side transmission system 19, the clutch built-in gear 38, the planetary gear mechanism 2
0, and S1 to S3 gears 39 to
41 is disposed on the bottom side of the camera body, and S4 to S10
The gears 42 to 47 and 14a are arranged on the upper surface side of the camera body, and the S3 gear 41 and the S4 gear 42 between them are
They are connected by a connecting shaft.

The clutch built-in gear 38 includes a first gear 38a.
, A second gear 38b, and a clutch mechanism (not shown) incorporated therebetween. This clutch mechanism has a rotational speed difference between the first gear 38a and the second gear 38b. When these occur, these connections are released so that each can rotate independently. In the clutch built-in gear 38, the first planetary gear 22 meshes with the first gear 38a when winding up the film, and the second planetary gear 23 meshes with the second gear 38b when winding up the film.

The take-up shaft side transmission system 19 includes an M1 gear 47 which meshes with the second planetary gear 23 when the film is wound up, and an M2 gear 15 integrally formed on the outer periphery below the take-up shaft 15.
a) is a reduction gear train composed of a.

FIGS. 1, 3, and 4 show the planetary gear mechanism 20. FIG. FIG. 1 is drawn upside down for convenience of explanation. As described above, the planetary gear mechanism 20 includes the sun gear 2
1, first and second planetary gears 22 and 23, and a planetary gear support arm 24. Planetary gear support arm 24
Is made of a resin and has a substantially U-shape. A sun gear support shaft 51 is provided at a bent portion 50a at the center, and a first planetary gear support shaft 52 is provided at both ends 24a and 24b. A second planetary gear support shaft 53 is formed.

The first and second planetary gears 22 and 23 are rotatably supported by first and second planetary gear support shafts 52 and 53 corresponding to the shaft holes 22a and 23a, respectively. 24. The first and second planetary gears 22 and 23 mesh with the sun gear 21, respectively, but the tooth width in the axial direction of the sun gear 21 is longer, and the second planetary gear 23 is larger than the first planetary gear 22. Meshes with the sun gear 21 at a position one step lower (higher in FIG. 1). The planetary gear support arm 24 includes the sun gear 21
The sun gear support shaft 51 is passed through the sun gear support shaft 51 so that the planet gear support arm 24 and the sun gear 21 are rotatable with respect to each other about a shaft 55 of the sun gear 21. ing.

At the bent portion 24a of the planetary gear support arm 24,
A pair of elastic resin arms 56 are provided. The pair of arms 56 are formed integrally with the planetary gear support arm 24 by molding, and are erected in a direction substantially parallel to the axis 55 of the sun gear 21, and are elastic in a direction along the diameter of the sun gear 21. Deformable. Further, a portion of the tip of each arm 56 facing outward with respect to the bent portion 24a is provided with a friction portion 56 as a friction member.
a is formed to slightly protrude outside the arm 56. Further, each arm 56 is provided at a position symmetrical with respect to the axis 55.

End face 2 of sun gear 21 facing bent portion 24a
A groove 57 into which the pair of arms 56 enters is formed in 1b. The groove 57 is formed in a circular shape around the shaft 55 of the sun gear 21, and an outer wall surface 57 a of the surface surrounding the groove 57 is an inner peripheral surface of a cylinder having the shaft 55 as an axis. It is shaped like a circle with the axis 55 as the center. The diameter of the wall surface 57 is smaller than the distance between the friction portions 56a of the pair of arms 56. In addition,
The other surface of the wall surface 56a only needs to have a shape that does not interfere with the arm 56 when the sun gear 21 rotates, but has a rotationally symmetric shape with the shaft 55a as a symmetric axis in consideration of the balance of rotation of the sun gear 21. Is good.

When the sun gear 21 is mounted on the sun gear support shaft 51, a pair of arms 56 reduce the distance between the friction portions 57a by the slope formed at the edge between the end surface 21b and the wall surface 57a. The friction portions 56a are pressed against the wall surface 56 with an appropriate pressure by the restoring force of the elastically deformed arm 56. At this time, since the pair of arms 56 are provided at positions symmetrical with respect to the shaft 55, this wall surface 57a
The frictional portion 56a presses the position at which the entire circumference is equally divided.

When the sun gear 21 rotates, the friction portion 56a
And the wall surface 57a slide, and the frictional force generated therebetween acts as a force for rotating the planetary gear support arm 24 in the same direction as the rotation direction of the sun gear 21 (hereinafter referred to as a revolving force). In this example, the kinetic friction force generated while the friction portion 56a slides on the wall surface 57a is used as the revolving force. However, the friction portion 56a and the wall surface 57a are rotated only when the planetary gears 22 and 23 revolve. If they are not relatively rotated, the revolving force becomes a static friction force.

When the rotation direction of the motor 16, that is, the sun gear 21 is switched by the revolving force, the planetary gear support arm 24 is rotated in the rotation direction of the sun gear 21 and is supported by the planetary gear support arm 24. The first and second planetary gears 22 and 23 revolve in the rotation direction of the sun gear 21. In addition, the sun gear 22 is attached to each of the planetary gears 22 and 23.
By applying a revolving force in the direction of rotation 1 to reduce these revolving loads and make them smaller than the rotation loads,
It can also be said that the planetary gears 22 and 23 are surely revolved in the rotation direction of the sun gear 21.

As described above, the friction portion 56a and the wall surface 57a for revolving the planetary gears 22 and 23 to reliably switch the transmission of the driving force are integrally formed with the planetary gear support arm 24 and the sun gear 21, respectively. Therefore, the number of parts can be reduced, and the number of parts can be reduced, so that the number of assembly steps and the assembly time can be reduced. Also, for each planetary gear 22, 23,
Since it is not necessary to form a member for obtaining a load, there is no inconvenience even if the diameter of each planetary gear 22 is reduced. Of course, it is only necessary to form the sun gear 21 with the wall surface 56a and the planet gear supporting arm 24 with the arm 56 (friction portion 56a) integrally. Is also easy.

Further, the first and second planetary gears 22, 23
To revolve in the direction of rotation of sun gear 21
It is necessary to adjust the frictional force between 6a and wall surface 57a, and this adjustment can be performed as follows. First, the planetary gear support arm 24 is formed such that the amount of protrusion of the friction portion 56a is reduced so that the frictional force between the friction portion 56a and the wall surface 57a is weakened. Next, the amount of protrusion of the friction portion 56a is gradually increased so as to increase the frictional force. That is, adjustment is performed so that the amount of elastic deformation of the arm 57 when the friction portion 56a is in contact with the wall surface 57a gradually increases. The modification of the mold of the planetary gear support arm 24 corresponding to this adjustment is performed by using the first friction portion 5 having a small convexity.
In the portion corresponding to 6a, a mold that is easy to work may be engraved so as to increase the concave amount. Therefore,
Since the appropriate adjustment of the frictional force is facilitated, the development and design time and cost of the planetary gear mechanism can be reduced.

Next, the operation of the above configuration will be described. After the cartridge 12 is loaded in the cartridge loading chamber, the motor 16 is rotated forward to perform the initial film feeding. Normally, at the beginning of this initial film feed,
The second planetary gear 23 is the second gear 3 of the clutch built-in gear 38.
8b, and the first planetary gear 22 is not meshed with any gear other than the sun gear 21 (see FIG. 5). When the motor 16 rotates forward, the sun gear 21 is rotated counterclockwise via the motor-side transmission system 17 as indicated by arrows in FIG. Then, since the wall surface 57a of the sun gear 21 rotates counterclockwise while sliding on the friction portions 57a of the pair of arms 57 formed on the planetary gear support arm 24, the planetary gear support arm 24
6a, a counterclockwise revolving force is applied from the wall surface 56a via the arm 56.

By the revolving force, the planetary gear support arm 24
Starts rotating about the shaft 55 in the same direction as the sun gear 21. Then, the first and second planetary gears 22 and 23 supported by the planetary gear support arm 24 start revolving in the same direction as the rotation direction of the sun gear 21 together with the planetary gear support arm 34. With this revolution, the first planetary gear 22 becomes
It moves toward the first gear 38a of the clutch built-in gear 38. The second planetary gear 23 is a gear 3 with a built-in clutch.
8 is disengaged from the second gear 38b, and moves toward the M1 gear 48, which is the input of the winding shaft side transmission system 19. Then, when the first and second planetary gears 22 revolve at a certain angle, as shown in FIG. 2, the first planetary gears 22 become the first gears 38a and the second planetary gears 23 become the M1 gears 4.
8 respectively.

During such a revolution, the second planetary gear 23
At the point in time when the meshing between the gears and the second gear 38b is released, the respective planetary gears 22 and 23 are not meshed with any gear other than the sun gear 21, so that the load on the rotation of the planetary gears 22 and 23 is almost eliminated, and the planetary gears 22 and 23 revolve. Is stopped, and the planetary gear support arm 24 is given a revolving force in the counterclockwise direction from the wall surface 56a as described above. Since the revolving force in the same direction as the rotation direction is applied, the revolving motion does not stop halfway, and the transmission of the driving force is reliably switched.

When the first planetary gear 22 meshes with the first gear 38a, the driving force of the motor 16 is transmitted to the first gear 38 via the motor-side transmission system 17, the sun gear 21, and the first planetary gear 22.
a, which is transmitted to the second gear 38b, and is transmitted from the second gear 38b through the respective gears 39 to 47 of the spool-side transmission system 18.
The power is transmitted to the ten gears 14a. As a result, the spool driving shaft 14 is rotated clockwise, and the spool 13 is rotated in the film feeding direction, so that the leading end of the photographic film 12a is sent out from the cartridge 12 toward the winding shaft 15 of the film winding chamber. It is. On the other hand, when the second planetary gear 23 meshes with the M1 gear 48, the motor 1
6 is transmitted through the M1 gear 48 to the M2 gear 15a.
And the winding shaft 15 is rotated clockwise.

When the leading end of the photographic film 12a reaches the rotating take-up shaft 15, the photographic film 12a is fed as described above by the action of a film suppressing roller provided around the take-up shaft 15. The leading end of the film 12a is wound on a winding shaft 15. In this way, the film is wound up by the rotation of the winding shaft 15 after the initial film feed is performed. During the film winding, the perforation of the first frame provided on the photographic film 12a is detected by a photo sensor or the like. When it is detected, the normal rotation of the motor 16 is stopped, and the first frame is set in the aperture. Thereafter, each time a photograph is taken, the photographic film 12a is wound up one frame at a time.

If the winding diameter of the winding shaft 15 increases during such initial film feeding or during film winding by one frame, the winding and winding shaft 1
The photo film 12a is pulled between the spool 5 and the spool 13, causing a difference in rotation speed between the first and second gears 38a and 38b of the clutch built-in gear 38. The first gear 38a and the second gear 38b are independently rotatable. Thereby, the spool side transmission system 18 is connected to the motor side transmission system 1.
7, the rotation is driven by the film feeding by the winding of the winding shaft 15.

When the photographing for all the frames is completed, the motor 16 is rotated in the reverse direction, and the film is rewound. When the motor 16 rotates in the reverse direction, the sun gear 21 rotates clockwise by the D6 gear 36 of the motor-side transmission system 17 as indicated by the arrow in FIG. When the sun gear 21 rotates clockwise, the wall surface 57a rotates clockwise while slidably contacting the friction portions 57a of the pair of arms 57. Therefore, the planetary gear support arm 24 moves the wall surface 56a through the friction portion 56a and the arm 56.
Gives a clockwise revolving force. Thereby, the first
The second planetary gears 22 and 23 start revolving together with the planetary gear support arm 24 in the same direction as the sun gear 21 about the shaft 55.

The first planetary gear 22 is a gear 3 with a built-in clutch.
8 is disengaged from the first gear 38a and moves counterclockwise. Further, the second planetary gear 23 is disengaged from the M1 gear 48 of the winding shaft side transmission system 19 and moves toward the second gear 38b of the clutch built-in gear 38. Then, when the first and second planetary gears 22 and 23 revolve at a certain angle, the first planetary gear 22 is not meshed with any gear other than the sun gear 21 as shown in FIG. The second planetary gear 23 meshes with the second gear 38b. Of course, even during this revolution, a revolving force in the clockwise direction is applied to the planetary gear supporting arm 24 from the wall surface 56a, and the revolving force in the same direction as the rotation direction of the sun gear 21 is applied via the planetary gear supporting arm 24 to each planetary gear. Since the rotation is given to 22, 23, the revolution does not stop halfway.

The second planetary gear 22 has a second gear 38.
b, the driving force of the motor 16 is transmitted through the motor-side transmission system 17, the sun gear 21, and the second planetary gear 23 to the second
The power is transmitted to the gear 38b and transmitted from the second gear 38b to the S10 gear 14a via the gears 39 to 47 of the spool-side transmission system 18. Thereby, the spool drive shaft 14
Is rotated in the counterclockwise direction, the spool 13 is rotated in the film rewinding direction, and the photographic film 12a wound on the winding shaft 15 is rewound on the spool 13 and stored in the cartridge 12. At this time, winding shaft 1
5 is an M1 gear 48 which is an input of the winding shaft side transmission system 19
Since the engagement between the photographic film 12a and the second planetary gear 23 is released, the photographic film 12a is driven to rotate in response to the feeding of the photographic film 12a toward the spool 13.

In the above embodiment, the frictional portion 56 of the arm 56 is provided on the outer wall surface 57a of the groove 57 formed in the sun gear 21.
a is pressed against the frictional portion 56a while the sun gear 21 is rotating, that is, a circumferential wall around the friction portion 56a and the shaft 55 of the sun gear 21. If so, a wall surface parallel to the axis 55, a vertical wall surface,
An inclined wall surface may be used. For example, the shaft 55 of the sun gear 21
In the case of the sun gear 21 shown in FIG. 1, in addition to the wall surface 57a, the inner wall surface 57b of the groove 57 formed so as to have a cylindrical outer peripheral surface, , Bottom surface 57c of groove 57 orthogonal to shaft 55, end surface 2 of sun gear
1b can be used. Further, since the wall surface of the conical surface formed around the axis of the sun gear also has a circular shape centered on the axis of the sun gear, it can also be used.

However, when the bottom surface 57c of the groove or the wall surface of the conical peripheral shape is used, the sun gear 21 does not act on the force in the direction along its axis 55, that is, does not act on the revolution of each planetary gear, but the sun gear 21 Since the frictional portion 56a receives a force that increases the rotation of the sun gear 21, the surface parallel to the shaft 55 of the sun gear 21, that is, the wall surfaces 57a and 57b of the groove 57 is used as described above. The friction part 56a is pressed against the sun gear 21 in the radial direction of the sun gear 21 so that the sun gear 2
It is preferable that a frictional force for revolving the planetary gears 22 and 23 between the sun gear 21 and the friction member 56a be generated by the radial pressure contact force.

FIG. 6 shows a case in which a groove is not formed in the sun gear 31 and a peripheral wall 60 having a shaft 55 as an axis is provided. The portion 56a is slid. Since other configurations are the same as those of the above embodiment, the same reference numerals are given to the same components in FIG.

FIGS. 7 to 9 show an example in which an arm having a friction portion with respect to the axis of the sun gear is extended substantially vertically. Note that portions other than those described below are the same as those of the first embodiment, and substantially the same components are denoted by the same reference numerals, and description thereof will be omitted. One end of the planetary gear support arm 24 on the side of the sun gear support shaft 51 is provided with a shaft 5.
A pair of arms 65 are formed extending substantially in the direction of rotation of the sun gear 21 along the direction of rotation of the sun gear 21. A friction portion 65a is formed at a distal end portion of the arm 65, and the friction portions 65a are arranged at symmetrical positions with respect to the axis 55. Then, the arm 65 enters the groove 57 formed in the sun gear 21, and
5a and the wall surface 57a are configured to slide.

With this configuration, the depth of the groove 57 can be reduced, so that the thickness of the sun gear 21 can be reduced, and the planetary gear mechanism 20 can be reduced in thickness. Note that the wall surface that slides on the friction portion 65a may be a surface inside the groove 57.

In each of the above embodiments, one or two planetary gears are used. However, two or more planetary gears may be used. In each embodiment, the two friction portions are in contact with the wall surface of the sun gear, but the number of the friction portions may be one or more. However, considering the balance of the rotation of the sun gear, it is preferable to use two or more pieces, and press the friction members at positions where the entire circumference of the wall surface to be pressed is equally divided. Further, in each of the above embodiments, none of the angles regulates the revolving angle of the planetary gear, but when regulating this,
A rotation restricting portion may be provided on a substrate, a camera body, or the like on which the planetary gear mechanism is mounted, and the planetary gear support arm may be locked by this.

[0043]

As described above, according to the planetary gear mechanism of the present invention, the planetary gear is supported by the wall formed integrally with the sun gear in a circular shape around the axis of the sun gear. By pressing with a friction member formed on the planet gear support arm, a friction force is generated between the wall surface and the friction member when the sun gear rotates, and a force in the same direction as the rotation direction of the sun gear is supported by the planet gear support. By giving it to the arm, the planetary gear and the planetary gear support arm revolve in the same direction as the rotation direction of the sun gear, so that the planetary gear revolves and the transmission of the driving force is reliably switched. Of course, the number of parts of the planetary gear mechanism can be reduced,
Also, the number of assembly steps and the assembly time can be reduced. As a result, manufacturing costs can be reduced.

The friction member provided on the planetary gear support arm is pressed against the sun gear in the radial direction of the sun gear, and the planetary gear is placed between the friction member and the sun gear by the radial pressing force of the sun gear. By generating a frictional force that causes the sun gear to revolve, it is possible to make the sun gear hardly apply a force that increases the rotation of the sun gear without acting on the revolution of the planetary gear.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an exploded planetary gear mechanism embodying the present invention.

FIG. 2 is a schematic diagram showing a state in which a film feeding device using a planetary gear mechanism winds up the film.

FIG. 3 is a plan view of the planetary gear mechanism.

FIG. 4 is a cross-sectional view showing a cross section of a sun gear and a first planetary gear of the planetary gear mechanism.

FIG. 5 is a schematic diagram showing a state in which the film feeding device using the planetary gear mechanism is rewinding the film.

FIG. 6 is an exploded perspective view showing a planetary gear mechanism in which a friction portion is directed inward.

FIG. 7 is an exploded perspective view showing a planetary gear mechanism in which an arm is extended along a circumferential direction of a sun gear in an exploded manner.

FIG. 8 is a plan view of the planetary gear mechanism of FIG. 7;

FIG. 9 is a sectional view showing a section of the planetary gear mechanism of FIG. 7;

[Explanation of symbols]

 Reference Signs List 21 sun gear 22, 23 planetary gear 24 planetary gear support arm 55 shaft 56 arm 56a friction portion 57 groove 57a wall surface

Claims (4)

[Claims] 1. A sun gear, a planet gear meshed with the sun gear, and a planet gear supporting arm rotatably mounted coaxially with an axis of the sun gear while rotatably supporting the planet gear. A planetary gear mechanism having: a sun gear formed on the sun gear, a circumferential wall concentric with the axis of the sun gear, and a friction member formed on the planet gear support arm and pressed against the wall, A planetary gear mechanism, wherein the planetary gear revolves by a frictional force generated between the friction member and the wall surface when the sun gear rotates. 2. The device according to claim 1, wherein the friction member is provided at a distal end of an elastic arm integrally formed with the planetary gear support arm, and is pressed against the wall surface by an elastic force of the arm. Item 3. The planetary gear mechanism according to Item 1. 3. The friction member according to claim 1, wherein a plurality of the friction members are provided, and the friction members are pressed into positions at which the entire circumference of the wall surface of the sun gear is equally divided. Planetary gear mechanism. 4. A sun gear, a planet gear meshed with the sun gear, and a planet gear supporting arm rotatably mounted coaxially with an axis of the sun gear while rotatably supporting the planet gear. In the planetary gear mechanism having the above, a friction member that is pressed against the sun gear in a radial direction of the sun gear is provided on the planetary gear support arm, and when the sun gear rotates, a friction member in a radial direction of the sun gear by the friction member is provided. A planetary gear mechanism, wherein a frictional force is generated between the friction member and the sun gear by a pressing force, and the planetary gear revolves with the frictional force.