JPH0659323A - Film winding mechanism for camera - Google Patents

Abstract

PURPOSE:To provide the film winding mechanism for a camera which can be formed to a small size and be reduced in cost. CONSTITUTION:A spool 10 is freely rotatably supported on a blind cylindrical supporting part 13 of a reduction gear support 12 by fitting of this supporting part 13 thereto. The body of a driving motor 14 is screwed to the base of the supporting part 13 and is positioned within the spool 10. A revolving shaft 16 of the driving motor 14 is extended through a through-hole provided on the base of the supporting part into the supporting part 13 and a motor gear 17 made of a resin is fitted to the revolving shaft within the supporting part. A reduction gear unit is flatly disposed and meshed with two pieces of reduction spur gears 22, 24 made of resins and is disposed within the supporting part 13. An external transmission gear 25 or the reduction gear unit or sun gears 23, 30 of an oscillation gear unit are disposed across the end edge of the spool, by which the external transmission gear 25 and the sun gears are intermeshed. Two pieces of the reduction spur gears 22, 24 are constituted of two stages of gears and pinions and the transfer coefft. thereof is set large within the range where the shaft is not adversely affected, by which the respective pinions are constituted to 6 or 7 pieces in the number of teeth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera film winding mechanism which can be formed compactly and inexpensively.

[0002]

2. Description of the Related Art In a camera film winding mechanism, a spool is rotatably supported in a camera body, a drive motor is supported so that the body is located in the spool, and a motor gear is attached to a rotation shaft of the drive motor. A multi-stage reduction gear device is connected to the motor gear, and an external transmission gear of the reduction gear device is meshed with a sun gear of an oscillating gear device forming a clutch mechanism. This oscillating gear device is provided on a oscillating arm that is oscillated about an axis and is provided on a sun gear that rotates about the axis and on the tip of the oscillating arm, and meshes with the sun gear. A planetary gear that rotates, wherein the planetary gear of the oscillating gear device selectively meshes with the spool gear and the rewinding gear that transmits the driving force to the rewinding mechanism at the oscillating position of the oscillating arm. Has become. When the drive motor rotates in the normal direction, the driving force is transmitted to the sun gear through the external transmission gear, and the sun gear or the planet gear is configured to require a predetermined torque. When the drive motor is rotated in the opposite direction, the swing arm swings in the opposite direction and the planetary gear is used as the rewinding gear. Mesh to drive the rewinding mechanism to rewind the film.

[0003]

By the way, since the camera tends to be further miniaturized, there is a strong demand for miniaturization of the camera film winding mechanism incorporated therein. The miniaturization of the camera film winding mechanism largely depends on the miniaturization of the gear group of the reduction gear device. The downsizing of these gear groups can be achieved by using a metal gear having high strength, but there is a problem that the metal small gear with high accuracy has a high processing cost. To make gears at low cost, it is better to use resin ones, but with resin ones, the module must be set large in order to secure the necessary tooth strength, and the pitch circle inevitably becomes large. , Contrary to the demand for miniaturization.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a camera film winding mechanism which can be formed in a small size and can be reduced in cost. .

[0005]

The present invention has the following constitution in order to achieve the above object. That is, a spool rotatably supported in the camera body, a drive motor positioned and supported in the spool, a motor gear attached to the rotation shaft of the drive motor, and a motor gear connected to the motor gear. A reduction gear device, a sun gear that rotates about the shaft on a swing arm that is swingably provided around the shaft, and a planetary gear that meshes with the sun gear on the tip of the swing arm, The sun gear includes an oscillating gear device that meshes with an external transmission gear of the reduction gear device, and the planetary gear of the oscillating gear device is a oscillating position of an oscillating arm, and a driving force is applied to a spool gear or a spool gear. In a camera film winding mechanism that selectively meshes with a winding gear that transmits a drive force and a rewinding gear that transmits a driving force to a rewinding mechanism, the spool is fitted with a cylindrical support portion of a reduction gear support body. To do Is rotatably supported on the support portion, the main body of the drive motor is screwed to the bottom surface of the support portion and positioned in the spool, and the rotary shaft of the drive motor has a through hole provided on the bottom surface of the support portion. The resin gear motor gear is fitted to the rotary shaft in the support portion so as to extend through the support portion, and the reduction gear device has two resin reduction spur gears arranged and meshed in a plane. The external transmission gear of the reduction gear device or the sun gear of the oscillating gear device is disposed in the bottomed cylindrical support portion so as to straddle a spool edge, and the external transmission gear and the sun gear are meshed with each other. , The two reduction spur gears are composed of two stages of a large gear and a small gear, and the transfer coefficient is set large within a range where the shaft is not adversely affected, so that the number of teeth of each small gear is 6 Or it is composed of 7 sheets There. The motor gear has a boss portion that fits into the rotation shaft of the motor, a shaft portion that is provided on the boss portion coaxially with the rotation shaft of the motor, and has a tooth bottom circle on the shaft portion that has a smaller diameter than the motor output shaft. It is preferable to have a tooth portion provided so that the number of teeth of the tooth portion is set to 5 to 7.

[0006]

According to the present invention, the support portion is formed into a cylindrical shape with a bottom and is fitted into the spool. The two reduction gear devices constituted by the spur gear group are housed in the support portion, and the driving force to the outside is accommodated. For transmission, the external transmission gear formed of spur gears or only the plate-shaped portion of the sun gear is arranged so as to straddle the spool edge, so that the size of the device can be reduced. Further, in the present invention, the number of teeth of the small gears of the two reduction spur gears is set to 6 or 7.
Generally, in an involute tooth profile, when the number of teeth is less than eight, an undercut portion is generated in the tooth profile, and particularly in a resin gear, the tooth strength becomes extremely poor. In this respect, in the present invention, the transfer coefficient of the reduction spur gear is set as large as possible within the range where the shaft is not adversely affected. As a result, even if the number of teeth is set to a small number of six or seven, undercut hardly occurs and the tooth strength can be sufficiently secured. 6 teeth
By setting the number to one or a small number of seven, the module has an appropriate size without increasing the pitch circle, and the tooth strength is secured. Therefore, a resin can be used to design a gear having a small diameter, and the device can be downsized as described above.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a development view of a gear group of the film winding mechanism, and FIG. 2 is a plan view. In the figure, 1
Reference numeral 0 denotes a cylindrical spool, and a spool gear 11 is formed on the outer periphery of one end of the spool, and is supported on a bottomed cylindrical support portion 13 of a reduction gear support 12 so as to be rotatable about an axis. Although not shown in the middle of the spool 10,
A feed pawl that fits into the feed hole of the film is provided.
Reference numeral 14 is a drive motor, and the support portion 13 is fixed by a screw 15.
Fixed to the bottom of the spool and the body is located within the spool 10.
The rotary shaft 16 of the motor penetrates through a through hole provided at the bottom of the support 13 and projects into the support 13.
Has a D-shaped cross section. Reference numeral 17 denotes a motor gear, which is integrally formed of synthetic resin and has a boss portion 18,
It is composed of a shaft portion 19 and a tooth portion 20. The motor gear 17 is fitted to the rotary shaft 16 with a predetermined clearance at the boss portion 18 and rotates together with the rotary shaft 16. Further, the motor gear 17 is supported at both ends by being axially supported by the head case 21 forming a lid at the tip of the shaft portion 19,
Shaft runout is prevented. The tooth portion 20 formed on the outer circumference of the shaft portion 19 is set so that the tooth bottom has a smaller diameter than the rotary shaft 17. The motor gear 17 has a small number of teeth of 5 to 7. The reduction gear support 12 is fixed together with the head case 21 and the camera body 26 by screws 39 as shown in FIG.

Reference numeral 22 is a reduction spur gear consisting of a large-diameter gear 22a meshing with the motor gear 17 and a small-diameter gear 22b, and 24 is a large-diameter gear 24a meshing with the gear 22b and a small-diameter gear 24b is two-stage. Is a reduction spur gear, and 25 is an external transmission gear that meshes with the gear 24b of the reduction spur gear 24. The external transmission gear 25 is set such that its plate-shaped gear body straddles the end edge portion of the spool 10 and a part of its tooth portion projects outside the spool 10. The reduction spur gear 22 and the reduction spur gear 24 are arranged in the bottomed cylindrical support portion 13. Each of the reduction spur gears 22 and 24 and the external transmission gear 25 is made of reinforced synthetic resin. And the small gear 22b of the reduction spur gears 22, 24,
The number of teeth of 24b is set to a small number of 6 to 7 in each case.

27 is a head case 21 and a camera body 2.
6 is an oscillating gear device installed between 28 is a swing arm of the swing arm, which is located near the outside of the spool 10 and is attached to a shaft 29 supported by the head case 21 and the camera body 26 with a predetermined frictional force so as to be swingable about the shaft 29. It is provided. Reference numeral 30 is a driven gear, which is fitted on the shaft 29 and meshes with the external transmission gear 25. Reference numeral 23 is a sun gear formed on the outer circumference of a shaft 29 on the opposite side of the driven gear 30 with the swing arm 28 interposed therebetween. Reference numeral 36 denotes a sliding plate provided at the end of the swing arm 28, which prevents the shaft 29 from swinging by being brought into contact with and guided by an arc-shaped guide 36 provided upright on the camera body 26. 31 is a shaft 32 provided on the tip of the swing arm 28
Is a planetary gear rotatably provided on the swing arm 28 and meshes with the sun gear 23. Planetary gear 3
1 is pressed against the swing arm 28 by the disc spring 33, and rotates with a predetermined frictional resistance with respect to the swing arm 28. The planetary gear 31 meshes with the spool shaft 11 when the swing arm 28 swings toward the spool 10 (FIG. 3). Further, the planetary gear 31 meshes with the rewinding gear 35 when it is swung in the direction opposite to the spool 10. The planet gear 31 may be meshed with the spool shaft 11 via an appropriate hoisting gear (not shown). The oscillating gear device 27, the rewinding gear 35 and the like are also made of synthetic resin.

With the above construction, when the drive motor 14 rotates in the forward direction, the external transmission gear 25 is rotated in a predetermined direction via the motor gear 17, the reduction spur gear 22, and the reduction spur gear 24. As a result, the sun gear 23 is rotated via the driven gear 30, but since the sun gear 23 meshes with the planetary gear 31 that requires a predetermined rotation torque, the rotation of the sun gear 23 also requires a predetermined rotation torque. Therefore, the swing arm 28 swings due to the resistance, the planetary gear 31 meshes with the spool gear 11, and the spool 10 rotates in the film winding direction to wind up the film. When the drive motor 14 is rotated in the opposite direction, the swing arm 28 is swung in the opposite direction, the planetary gear 31 rotates the rewinding gear 35, and the film is rewound into the cartridge by a known mechanism. is there.

As described above, the support portion 13 is formed into a cylindrical shape with a bottom and is fitted into the spool 10. The reduction gear device constituted by the spur gear group is housed in the support portion 13 and is connected to the outside. For transmission of the driving force, only the plate-shaped portion of the external transmission gear 25, which is a spur gear, is arranged so as to straddle the spool edge, so that the substantial thickness of these reduction gear groups can be reduced, and Can be miniaturized. Further, as described above, the tooth portion 20 of the motor gear 17 is set so that its tooth bottom has a diameter smaller than that of the rotating shaft 16. Moreover, by setting the diameter of the shaft portion 19 to be small in the tooth portion 20, the root diameter can be freely set to be small. Therefore, the number of teeth of the tooth portion 20 is small, for example, conventionally, only about 8 to 9 can be set, but in the present embodiment, it can be set to about 5 to 7, and the reduction ratio can be increased. Incidentally, in the present invention, the number of teeth of the small gears 22b and 24b of the reduction spur gears 22 and 24 is also set to a small number of 6 to 7. It is extremely difficult to reduce the number of teeth in a small diameter gear. Generally, the pressure resistance tooth strength P is represented by P = σmbY. σ is material stress, m is module, b is tooth thickness, and Y is tooth profile coefficient.
In the case of metal, the material stress σ is large, so module m
Is small, therefore the pitch circle is small, and even if the number of teeth is large, a large pressure resistant tooth strength can be obtained. That is, a gear with a small diameter can be made. However, when the material is synthetic resin, the material stress σ is small, so in order to secure the pressure resistant tooth strength to the required size, the module must be made large, so the pitch circle becomes large and the large diameter I could only make gears. As described above, such a large-diameter gear runs counter to the demand for miniaturization of the camera. On the other hand, in order to keep the pitch circle small and increase the module size, it is conceivable to reduce the number of teeth, but in the case of an involute tooth profile, undercutting occurs when the number of teeth is 13 or less, especially in the case of metal. Due to the cutting process, the number of teeth is limited to eight. When the material is synthetic resin, molding is possible even if an undercut portion occurs, but as shown in Fig. 4, the tooth root is largely undercut, and therefore the synthetic resin has extremely strong tooth strength. It becomes bad and cannot be adopted. In the involute tooth profile, the undercut of the tooth profile is the tooth profile coefficient Y, and thus the module m and the transfer coefficient X.
Related to. The inventor has conceived that by increasing the transfer coefficient X, the undercut shape of the tooth profile can be eliminated even when the number of teeth is reduced. That is,
Even if the number of teeth was 6 to 7, the undercut of the tooth profile was almost eliminated, and the required tooth strength could be obtained. Table 1 shows data of each gear in the embodiment shown in the drawing.

[0012]

[Table 1]

As is clear from Table 1, the small gear 22b,
The transfer coefficients of 24b are set to 0.599 and 0.693, respectively. The conventional normal transfer coefficient is about 0.5.
If the transition coefficient is increased in the involute tooth profile, the so-called meshing pressure angle increases and the bearing loss increases. In the above-described embodiment, the transition coefficient is set as large as possible within the range where the shaft is not adversely affected so that the tooth profile is not undercut and the necessary tooth strength is secured. And this
Even if the gear diameter is small by setting the pitch circle relatively small,
The module can be enlarged and the required tooth strength can be increased. Further, the reduction spur gears 22 and 24 have a small diameter and can be arranged in a cylindrical support portion having a bottom, and the reduction gear mechanism can be downsized. Although the plate-shaped portion of the external transmission gear 25 straddles the end edge of the spool 10 in the above embodiment, the driven gear 3
You may make it the plate-shaped part of 0 straddle the spool edge. Further, in the above embodiment, the sun gear 23 and the driven gear 30
Although and are provided separately, they may be integrated into one.

[0014]

According to the present invention, as described above, the support portion is formed into a cylindrical shape with a bottom and is fitted in the spool, and the reduction gear device constituted by the spur gear group is housed in the support portion. For the transmission of driving force to the outside, only the external transmission gear consisting of spur gears or the plate-shaped part of the sun gear is arranged so as to straddle the spool edge, so reduce the substantial thickness of these reduction gear groups. Therefore, the device can be downsized. Further, in the present invention, the number of teeth of the small gears of the two reduction spur gears is set to 6 or 7. Generally, in an involute tooth profile, when the number of teeth is less than eight, an undercut portion is generated in the tooth profile, and particularly in a resin gear, the tooth strength becomes extremely poor. In this respect, in the present invention, the transfer coefficient of the reduction spur gear is set as large as possible within the range where the shaft is not adversely affected. As a result, even if the number of teeth is set to a small number of six or seven, undercut hardly occurs and the tooth strength can be sufficiently secured. By setting the number of teeth to a small number such as 6 or 7, the module can have an appropriate size and the tooth strength can be secured without increasing the pitch circle. Therefore, a resin can be used to design a gear having a small diameter, and the device can be downsized as described above. Further, in the present invention, the number of teeth of the motor gear can be set to a small number of 5 to 7, and the reduction ratio can be increased.

[Brief description of drawings]

FIG. 1 is a development view of a gear group of a film winding mechanism.

FIG. 2 is a development view of a gear group of a film winding mechanism.

FIG. 3 is a plan view of a gear group of a film winding mechanism.

FIG. 4 is an explanatory diagram of an undercut shape of a tooth profile.

[Explanation of symbols]

 10 spool 12 reduction gear support 13 support portion 14 drive motor 16 rotary shaft 18 boss portion 19 shaft portion 20 tooth portion 22, 24 reduction spur gear 23 sun gear 25 external transmission gear 27 swing gear device 29, 32 shaft 31 planetary gear 35 rewinding gear

Claims (2)

[Claims] 1. A spool rotatably supported in a camera body, a drive motor positioned and supported in the spool, a motor gear attached to a rotation shaft of the drive motor, and a motor gear. A reduction gear device connected to the sun gear, a sun gear that rotates on the swing arm that is swingably provided around the shaft, and a planetary gear that meshes with the sun gear on the tip of the swing arm. A planetary gear of the oscillating gear device, wherein the sun gear is in mesh with an external transmission gear of the reduction gear device, and the planet gear of the oscillating gear device is in a oscillating position of an oscillating arm. In a camera film winding mechanism that selectively meshes with a hoisting gear that transmits a driving force to a rewinding mechanism and a rewinding gear that transmits a driving force to a rewinding mechanism, the spool has a bottomed cylindrical support of a reduction gear support. Part fits in Is rotatably supported on the support portion, the main body of the drive motor is screwed to the bottom surface of the support portion and positioned in the spool, and the rotation shaft of the drive motor is a through hole provided on the bottom surface of the support portion. And extends into the support portion, the motor gear made of resin is fitted to the rotary shaft in the support portion, and the reduction gear device has two reduction spur gears made of resin arranged in a plane and meshed with each other. Is arranged in the bottomed cylindrical support portion, the external transmission gear of the reduction gear device or the sun gear of the oscillating gear device is arranged straddling the spool edge,
The external transmission gear and the sun gear are meshed with each other, and the two reduction spur gears are composed of two stages of a large gear and a small gear, and
A film winding mechanism for a camera film, wherein the transfer coefficient is set to a large value within a range that does not adversely affect the shaft, and the number of teeth of each of the small gears is 6 or 7. 2. The motor gear has a boss portion fitted to a rotation shaft of the motor, a shaft portion provided on the boss portion coaxially with the rotation shaft of the motor, and a bottom tooth circle on the shaft portion having a motor output. The camera film winding mechanism according to claim 1, further comprising a tooth portion having a diameter smaller than that of the shaft, wherein the number of teeth of the tooth portion is set to 5 to 7.