JP2011196525A - Drive transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assemblability without disposing an elastic member between a main gear and a sub gear composing a scissors gear, not limited by a shape of a gear tooth face.SOLUTION: The drive transmission device has an energizing means for applying an energizing force from an outer face side of one of a first gear or a second gear toward the other gear. At least one of the connection parts of a first connection part or a second connection part is provided with an inclined face, and by contacting the other connection part by the inclined face, the second gear in a rotating direction of the second gear energizes a tooth face of a third gear interlocking with the first gear and the second gear.

Description

  The present invention relates to a drive transmission device using gears, and more particularly to a configuration for removing the influence of backlash.

  2. Description of the Related Art Conventionally, an image forming apparatus that forms an image on a recording material includes a drum rotating mechanism for rotating a photosensitive drum, and a sheet conveying mechanism for conveying a sheet to an image forming unit. The sheet conveying mechanism and the drum rotating mechanism of these image forming apparatuses include a gear (gear) pair that is rotated by a driving force from a driving unit such as a motor, and the driving force from the driving unit is supplied to the driven unit by the gear pair. Is provided with a gear device for transmission to the motor.

  In a gear device, it is necessary to always set an appropriate gap (backlash) between meshing gears for smooth rotation transmission by the gears. However, when such backlash is set, a phenomenon occurs in which the tooth surfaces strike each other when the gear is driven, resulting in vibration and noise.

  As a countermeasure, an auxiliary gear with the same number of teeth is provided on the side surface of the main body gear, and the auxiliary gear is connected to the main body gear with a torsional force in the rotational direction by a spring provided between the auxiliary gear and the main body gear. There is one using a scissors gear mechanism that is configured to do so (see Patent Documents 1 and 2). In the scissors gear mechanism configured as described above, when the counter gear rotates, the teeth of the counter gear are sandwiched between the teeth of the auxiliary gear and the teeth of the main body gear, thereby reducing rattling.

  FIG. 16 is a diagram illustrating a configuration including a scissor gear mechanism provided in such a conventional gear device. The scissors gear meshes with the main gear 122 shown in FIG. 16A, a sub gear 123 that rotates so as to follow the main gear 122 by a spring provided between the gears, and the two gears 122 and 123. A drive gear 121 shown in FIG. 16B is provided.

  Then, as shown in FIG. 16B, when the drive gear 121 is rotated in the direction of arrow a, first, the tooth 121a comes into contact with the tooth 122a of the main gear 122 at the application point p, and the main gear 122 is moved to the arrow b. Rotate in the direction. Thereafter, the tooth 123a of the subsequent sub-gear 123 is pressed into contact with the tooth 121a of the drive gear 121 from the rear side in the rotational direction at the applied force point q by the biasing force of the spring.

  As a result, the backlash generated after the teeth 121a of the drive gear 121 is removed, and even if torque fluctuation occurs, the applied force point p is not separated, and the tooth strike is reduced. By pinching the gear using an elastic member such as a spring in this way, it is possible to reduce tooth fluttering and to reduce noise during driving.

  FIG. 17 is also a diagram illustrating a configuration including a scissor gear mechanism. In the figure, 131 is a drive gear press-fitted into an output shaft such as a motor (not shown). Further, 132 is a main gear rotatably supported on a rotating shaft 135, 133 is a sub-gear that is rotatably engaged with the main gear 132, and 134 is a torsion that applies a biasing force between the main gear 132 and the sub-gear 133. It is a spring. In FIG. 17, the sub gear 133 is shown in a half section so that the torsion spring 134 can be seen. In this way, one end of the torsion spring 134 is hooked on the main gear 132 and the other end is hooked on the sub gear 133 using holes or the like provided on the respective gear hub surfaces, and the torsion springs exert a rotational force on each other. It is a mechanism. However, as the gear itself becomes smaller with the recent product miniaturization, it is difficult to incorporate the torsion spring.

  In view of this, a gear mechanism having a configuration as shown in FIG. 18 has been proposed as a configuration in which no elastic member is provided between the gears. In the figure, 141 is a drive gear, 142 is a main gear having main teeth meshing with the tooth grooves, 143 is a sub gear having sub teeth, and is arranged on the same rotation axis as the main gear 142 and together with the main gear 142, the drive gear 141 It meshes with the tooth gap. Further, the main gear 142 and the sub gear 143 are configured to apply a biasing force in a direction relatively approaching the rotation axis direction by a biasing means (not shown). Here, the main tooth of the main gear 142 is formed with an inclined surface 142 (a) inclined in the direction in which the thickness of the main tooth 142 becomes thinner toward the sub gear 143 side. On the other hand, an inclined surface 143 (a) that is inclined in the direction in which the thickness of the sub teeth 143 decreases toward the main gear 142 side is also formed on the sub teeth of the sub gear. At this time, the main teeth and the sub teeth mesh with the tooth grooves of the drive gear 141 in a state in which a part of the inclined surfaces face each other. The urging force in the direction of the rotational axis gives a rotational force due to the inclined surfaces, and the scissors gear configuration improves the assemblability and the engagement rate. (See Patent Document 3)

JP-A-8-109961 JP-A-9-89082 JP-A-11-303974

  Although the proposal of the structure shown in FIG. 18 is also made and the problem of assemblability is reduced, in such a structure, the tooth is divided so that the gear tooth surface becomes very small and the tooth surface strength becomes weak. Rotational transmission errors are likely to occur. Since the gear tooth surface is very small, the gear circle pitch and the tooth thickness due to processing errors vary, so that the backlash amount is not always constant. This causes a change in the amount of backlash during rotation.

  Accordingly, the present invention provides a rotatable rotating shaft, a first gear attached to the rotating shaft and rotating integrally with the rotating shaft, a first gear attached to the rotating shaft and rotatable with respect to the rotating shaft. Two gears, a first gear and a second gear arranged so as to mesh with each other, a drive gear, a third gear, and an inner surface of the first gear facing the second gear, A first connecting portion for connecting the first gear and the second gear; and a second connecting portion provided on an inner surface of the second gear facing the first gear and connected to the first connecting portion. An urging means for applying an urging force from the outer surface side of at least one gear of the first gear or the second gear to the other gear, and At least one of the first connecting part or the second connecting part The coupling portion inclined surface are provided, wherein the second gear in the direction of rotation of the second gear by the inclined surface is in contact with the other connecting portion urges said three gears.

  According to the present invention, without being limited to the shape of the gear tooth surface, the ease of assembly can be improved by not disposing an elastic member between the main gear and the sub gear constituting the scissor gear.

The figure which shows the structure of the gear apparatus which concerns on the 1st Embodiment of this invention. Assembly drawing of the gear unit The perspective view which shows the structure of the 1st gearwheel provided in the said gear drive apparatus. The perspective view which shows the structure of the 2nd gearwheel provided in the said gear drive apparatus. Assembly drawing of the gear unit (half section) Perspective view of rotating shaft Illustration of balance of force on inclined surface Inclined perspective view Inclined perspective view The figure which shows the structure of the gear apparatus which concerns on the 2nd Embodiment of this invention. The perspective view which shows the structure of the 2nd gearwheel provided in the said gear drive apparatus. The side view which shows the structure of the gear apparatus which concerns on the 2nd Embodiment of this invention. The figure explaining the structure of the copying machine which concerns on 1st Example of this invention provided with the said gear apparatus. The perspective view which shows the structure of the drive part of the sheet conveyance part provided in the said copying machine. The figure explaining the structure of the electronic camera which concerns on 2nd Example of this invention provided with the said gear apparatus. The figure explaining the structure of the scissors gear mechanism provided in the said conventional gear apparatus. The figure explaining the other structure of the scissors gear mechanism provided in the said conventional gear apparatus. The figure explaining the other structure of the scissors gear mechanism provided in the said conventional gear apparatus.

(First embodiment)
A drive transmission mechanism to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a perspective view of a gear pair of a first embodiment to which the present invention is applied, FIG. 2 is an assembled view of the gear pair, FIG. 3 is a perspective view of the inner side of the first gear, and FIG. FIG. FIG. 5 is a view showing a state where the first gear and the second gear are connected, and the second gear is shown in a half section so that the connecting portion can be seen. FIG. 6 is a perspective view of the rotating shaft.

  First, the first gear will be described. Referring to FIG. 1, reference numeral 1 denotes a first gear. The first gear 1 has a tooth forming portion 1 (a) that transmits a driving force. The first gear 1 is fixed so that the first gear 1 does not move with respect to the rotating shaft 3. Therefore, as shown in FIG. 3, the portion supported by the rotating shaft 3 is a D-cut shape portion such as the engagement holes 1 (d) and 1 (e). In addition, the first gear 1 is in contact with and slides on a cylindrical portion 1 (b) that is rotatably engaged with a second connecting portion formed on the inner surface of the second gear and a part of the second connecting portion. It has an inclined surface 1 (c). The cylindrical portion 1 (b) is a cylindrical portion centered on the rotation center of the first gear 1, and the inclined surface 1 is configured to be perpendicular to the surface of the cylindrical portion. The cylindrical portion 1 (b) and the inclined surface 1 provided in the first gear 1 have a function as a first connecting portion that is connected to the second connecting portion.

  Next, the second gear will be described. Referring to FIG. 1, reference numeral 2 has a tooth forming portion 2 (a) for performing drive transmission with a second gear. Further, as shown in FIG. 4, the second gear 2 is provided with a part 2 (b) of the cylindrical portion so as to be rotatable with respect to the rotation shaft 3, and this portion is attached to the rotation shaft 3. It is supported. Referring to FIG. 4, it has a second inclined surface 2 (c) that comes into contact with the inclined surface (c) of the first gear 1.

  Next, the rotating shaft 3 will be described with reference to FIG. The rotating shaft 3 is configured such that when the driving force is transmitted to the first gear 1 and the first gear 1 rotates, the rotating shaft 3 rotates. The rotating shaft 3 includes a flange portion 3 (a) for restricting the position of the gear pair in the rotating shaft direction of the rotating shaft 3, a D-cut portion 3 (b) for preventing rotation with the first gear, and an E-ring. Grooves 3 (c), 3 (d), and 3 (e) for attaching a retaining ring such as the like are formed. The rotating shaft 3 is rotatably supported by a sheet metal frame (not shown). Then, when the rotating shaft 3 rotates, the driving force is transmitted to the object to be rotated.

  In FIG. 6, reference numeral 4 denotes a retaining ring that fits into the grooves 3 (c), 3 (d), and 3 (e) of the rotating shaft 3. Reference numeral 5 denotes a compression coil spring, which is an elastic member as an urging means, and is applied to the rotary shaft 3 in a state compressed by the retaining ring 4 so as to press the second gear in the rotational axis thrust direction (the direction of the first gear). It has been incorporated. In this embodiment, the compression coil spring 5 has a configuration in which the second gear biases the second gear from the outer surface side opposite to the inner surface facing the first gear, but is not limited thereto. For example, if the position of the second gear, which is one of the gears, is restricted by the flange portion, even if it is configured to be urged by the compression coil spring from the outer surface side of the first gear, which is the other gear. Good. However, the elastic member that is the urging means is not arranged between the first gear and the second gear in order to improve assemblability. Reference numeral 6 denotes a thrust receiving plate made of a resin material having good sliding properties such as POM (polyacetal), which is in contact with the end face of the compression coil spring 5 so that the second gear rotates smoothly. In the present embodiment, the first gear 1 and the second gear 2 are resin gears, and of course, there is no problem even if they are metal gears.

  Next, a mechanism for generating the rotational force of the gear pair assembled in this configuration will be described with reference to FIGS.

  The cylindrical portion 1 (b) of the first gear 1 and the cylindrical portion 2 (b) of the second gear 2 are connected mechanisms that allow the second gear 2 to rotate relative to the first gear 1. It constitutes. Further, the inclined surface 1 (c) and the second inclined surface 2 (c) are brought into contact with each other by the compression coil spring 5, and the gears are urged toward each other. The inclined surface 1 (b) formed on the first gear 1 and the second inclined surface 2 (b) formed on the second gear 2 are formed at the same inclination angle θ (see FIG. 5). Thus, the ease of rotation of the second gear 2 is determined. In this embodiment, as a general configuration, the inclination angle is set in the range of θ of 35 to 55 deg shown in FIG. 5, but depending on the setting of the slidability and the backlash force of the gear, it is limited to this range. is not.

  FIG. 7 is a schematic diagram showing a state in which the inclined surfaces 1 (c) and 2 (c) of the first gear 1 (fixed side gear) and the second gear 2 (movable side gear) are in contact with each other.

  In this figure, one tooth surface 1 (a) of the first gear 1 and one tooth surface 2 (a) of the second gear 2 apply a driving force that meshes with both the first gear 1 and the second gear 2. The part of a connection mechanism in the state which is pinched | interposed and meshed | engaged between the tooth surfaces (dotted line part in a figure) of the drive gear (3rd gear) for this is shown.

Here, W is the force received by the tooth surface 2 (a) of the second gear 2 due to the backlash fluctuation caused by the tooth pitch error of the drive gear, N is the drag received by the second gear 2 from the first gear 1, and the inclined surface. the frictional force between F, the static friction coefficient mu, the inclination angle of the inclined surface theta (deg), when the force which the second gear 2 is going to move to the P _G, is obtained the following equation from the balance conditions.
N = W × COS (θ)
F = μN
P _G = W × SIN (θ) −F
Here, if W = 100 g, μ = 0.1, and θ = 45 deg, the force P _G is P _G = 100 × SIN (45) −0.1 × 100 × COS (45) = 63.64 (g )
Thus, the component force of this value P _G = 63.64 g becomes the force for rotating the second gear 2. As component force is large this P _G, but not even be an easy condition to rotate will be described here, P _{G =} 49.50g next When 0.3 the friction coefficient μ under the above conditions, the inclination It can be confirmed that if the coefficient of friction μ between the surfaces is reduced, it becomes easier to rotate.

  Therefore, in the present embodiment, the shape of the inclined surface 1 (c) of the first gear 1 is configured as shown in FIGS. 8 to 9, thereby reducing the frictional force. In FIG. 8, a substantially semi-cylindrical ridge line portion 1 (f) is formed in the longitudinal direction on the first gear 1 inclined surface 1 (c). Here, the inclined surface 2 (c) arranged and slid opposite to the inclined surface 1 (c) may be a planar surface as shown in FIG. Under such a configuration, the urging force of the compression coil spring 5 causes the substantially semi-cylindrical ridge line portion 1 (f) and the inclined surface 2 (c) as the sliding surfaces to come into contact with each other and the rotational force between the gears. Will be given. At this time, the ridgeline portion 1 (f) having a substantially semi-cylindrical shape comes into contact with the inclined surface 2 (c), and the portion in contact with the ridgeline portion 1 (f) is reduced so that it can rotate with very little frictional resistance.

  FIG. 9 also shows a configuration for reducing the frictional resistance, and a plurality of substantially hemispherical protrusions 1 (g) are locally formed on the inclined surface 1 (c). As a result, the tip end portion of the sphere R of the substantially hemispherical projection 1 (g) comes into contact with the inclined surface 2 (c), and the state is rotatable with very little frictional resistance.

  The rotational force generated here is balanced by the compression coil spring 5 via the thrust receiving plate 6. However, in this embodiment, in order to be able to easily change the urging force by the compression coil spring 5, the rotation shaft is provided with a groove portion for attaching the retaining ring 4 at several places so that a desired urging force can be applied. ing.

With such a configuration, the scissors gear mechanism can be formed using the first gear and the second gear. That is, at least one tooth surface of the drive gear is sandwiched between the tooth surface at the position of the first gear and the tooth surface of the second gear, thereby eliminating backlash caused by the meshing of the gears. be able to.
In this embodiment, permanent magnets are provided on the inner surfaces of the first gear and the second gear, respectively, and the phase of the tooth surface of the second gear with respect to the tooth surface of the first gear in the rotational direction varies greatly. It has a difficult structure. However, even with a configuration in which a permanent magnet is provided, the position of the second gear relative to the first gear can vary depending on the positional relationship between the tooth surface of the drive gear, the tooth surface of the first gear, and the tooth surface of the second gear. It is said.

  Further, in this embodiment, the scissor gear mechanism has a configuration of a drive transmission path arranged on the side where the driving force is transmitted, but even if it has a configuration of a drive transmission path arranged on the side where the driving force is transmitted, The same effects as in the present embodiment can be obtained.

  In the present embodiment, the inclined surface is provided on each gear, but the inclined surface may be provided on at least one gear. That is, in the case where the inclined surface is provided only on one gear, the other gear only needs to have a contact portion that contacts the inclined surface, and the shape of the contact portion is not limited to the inclined surface. .

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the second embodiment, the configuration of the second gear is changed with respect to the first embodiment. The changed configuration will be described.

  FIG. 10 is a perspective view of the gear pair of the second embodiment, FIG. 11 is a perspective view of the second gear, and FIG. 12 is a side view of the gear pair.

  Next, the mechanism for generating the rotational force of the gear pair assembled in this configuration will be described with reference to FIGS.

  In FIG. 10, reference numeral 7 denotes a first gear similar to that of the first embodiment, and reference numeral 8 denotes a second gear in which a thrust leaf spring 10 is integrally provided on the side of the gear as shown in FIG. The second gear is provided with a plurality of protrusions 8 (b) for positioning a later-described thrust leaf spring and a tooth surface 8 (a) for driving transmission. Reference numeral 9 denotes a rotating shaft that is fitted into the first gear 7 by press-fitting and rotates integrally. Reference numeral 10 denotes a positioning hole 10 (a) by a thrust plate spring, and an arm portion 10 that has been deformed by a predetermined amount in order to apply an urging force. (B) is provided over a plurality of locations, and is integrally attached to the side surface of the second gear 8. A part of the arm 10 (b) has a protrusion 10 (c) for reducing sliding resistance, and this protrusion 10 (c) abuts against the side surface of the thrust receiving plate 11 to a predetermined amount. The urging force is applied to the second gear 8. The thrust receiving plate 11 is positioned by a component (not shown) and is configured not to move in the thrust direction (rotational axis direction) of the rotary shaft 9.

  In the present embodiment, a flexible material such as POM is used for the material of the second gear 8, while the thrust leaf spring 10 is phosphor bronze having a plate thickness of 0.1 to 0.3 mm suitable as a leaf spring material. Plates and spring stainless plates are used. For this reason, it is possible to integrally form the thrust leaf spring by insert molding at the time of gear molding. Further, if the second gear 8 is made of a flexible material having better spring properties, the thrust leaf spring 10 is not required, and it is possible to integrally form an arm portion as a spring for generating a biasing force. Needless to say.

  As described above, in the second embodiment, the second gear is offset by using the leaf spring, so that the space for the spring of the rotating shaft is reduced, and a smaller scissor gear mechanism can be provided. And it can be set as the form suitable also for the drive mechanism of not only an image forming apparatus but a small electronic device.

  FIG. 13 is a diagram illustrating the configuration of the image forming apparatus according to the first example that includes the drive transmission device according to the present embodiment. In this embodiment, the drive transmission device according to the present embodiment is used for the sheet conveyance system.

  In FIG. 13, 20 is an image forming apparatus, and 21 is an image forming apparatus main body. An image reading unit 22 that reads a document 30 placed on a platen glass 31 as a document placement table is provided on the upper portion of the image forming apparatus main body 21.

  The image reading unit 22 includes a light source 32 such as a halogen lamp or a fluorescent lamp that illuminates the original, and a CCD 34 that forms an image of light from the light source 32 with a lens 33 and obtains a color separation image signal. The color-separated image signal obtained by the CCD 34 is processed by a video processing unit through an amplification circuit (not shown) and transmitted to a laser exposure optical system 38 to be described later.

  On the other hand, the image forming apparatus main body 21 has an image forming unit 23, a sheet feeding unit 24 that feeds the sheet S stored in the paper feeding cassette 43, and a sheet conveyance that transports the sheet fed from the sheet feeding unit 24. A sheet conveying unit 25, a fixing unit 44, and the like constituting the system are provided. The image forming unit 23 includes a photosensitive drum 35 that is an image carrier that is rotatable in the arrow direction. Further, a pre-exposure lamp 36 for discharging the photosensitive drum 35 and a corona charger 37 for charging the photosensitive drum 35 are provided. A transfer device 41 for transferring the toner on the photosensitive drum to the recording material, a cleaning device 42 for removing the toner on the photosensitive drum, and a potential sensor 39 for detecting the potential on the photosensitive drum are provided. The image forming unit 23 develops an electrostatic latent image formed on the photosensitive drum 4 using yellow, cyan, magenta, and black toners based on a resin and a pigment as described later. The developing devices 40y, 40c, 40m, and 40Bk are provided. The transfer device 41 includes a transfer drum, a transfer charger, an adsorption roller that is opposed to an adsorption charger for electrostatically adsorbing a recording material, an inner charger, and an outer charger. A recording material-carrying sheet made of a dielectric material is integrally stretched in a cylindrical shape in a peripheral opening area of the transfer drum that is axially supported so as to be rotationally driven. The recording material-carrying sheet uses a dielectric sheet such as a polycarbonate film in the apparatus of this embodiment.

  In FIG. 13, reference numeral 38 denotes a laser exposure optical system. The laser exposure optical system 38 includes a laser driver (not shown), a polygon mirror that horizontally scans laser light from the laser driver, and the like.

  Next, an image forming operation of the copying machine 20 having such a configuration will be described.

  When a document image is read by the image reading unit 22, a color color separation image signal of yellow, cyan, magenta or black is sent from the image reading unit 22 to the laser exposure optical system 38. Based on this image signal, laser light is output from the laser exposure optical system 38 for each separated color, and this laser light scans the photosensitive drum 35.

  At this time, the photosensitive drum 35 is charged in advance with a predetermined polarity and a predetermined voltage by a corona charger 37, and an electrostatic latent image is formed on the surface by irradiation with laser light. Next, a toner image of the selected color is formed by the plurality of developing devices 40y, 40c, 40m, and 40Bk.

  Here, in the full color mode, for example, a yellow developing device 40y is disposed at a position facing the photosensitive drum 35 in order to develop a yellow electrostatic latent image as the first color. A colored yellow toner image is formed on the photosensitive drum. Thereafter, the photosensitive drum 35 to which the yellow toner image has been transferred rotates so that the next toner image is formed and transferred. During this time, the next designated color developing device moves to a position facing the photoconductive drum 35 to prepare for developing the next electrostatic latent image. Thus, in the full color mode, electrostatic latent image formation, development, and transfer are repeated until a predetermined number of toner images have been transferred.

  On the other hand, a control device (not shown) drives the sheet feeding unit 24 at a predetermined timing and feeds the sheet S from the sheet feeding cassette 43. Thereafter, the fed sheet S is conveyed to the registration roller 46 by the sheet conveyance unit 25, and then the skew is corrected by the registration roller 46. Further, the photosensitive drum 35 and the transfer device 41 are timed to match each other. Sent to the configured transfer section.

  Next, the full color toner image on the photosensitive drum is transferred to the sheet S sent to the transfer unit. When the transfer of the four color toner images is completed in this way, the sheet S is separated from the transfer device 41 by the actions of a separation claw, a separation push-up roller, and a separation charger (not shown) and conveyed to the fixing device 44. Thereafter, the unfixed transfer image is permanently fixed on the sheet S by being heated and pressurized by the fixing device 44, and the sheet S on which the image is fixed in this manner is discharged to the paper discharge tray 45.

  The toner remaining on the photosensitive drum after being transferred to the sheet S is cleaned by the cleaning device 42, and after the residual toner is cleaned by the cleaning device 42 in this manner, the photosensitive drum 35 is formed again. Provided to the process.

  Here, in the copying machine 20 according to the present embodiment, in order to shorten the first copy time and to narrow the sheet interval during image formation, the sheet conveyance speed to the registration roller 46 by the sheet conveyance unit 25 is the image formation speed (registration roller). Speed of 2 times or more).

  For this reason, the sheet conveying unit 25 constituting the sheet conveying system is provided with first and second drive motors 47 and 48 which are driving units corresponding to the sheet cassette 43. The first and second drive motors 47 and 48 are driven at a high speed until the sheet S is conveyed to the registration roller 46, and after the sheet S reaches the registration roller 46, the image forming speed (low rotation). It is driven to be driven by.

  As in this embodiment, in the sheet conveying unit 25 in which two (plural) drive motors 47 and 48 are arranged, the rotation speed on the high rotation side has a value that is twice or more the rotation speed on the low rotation side. In this case, the torque of the motor at the time of low rotation becomes a value several times the required torque.

  In the case of motor driving with such a surplus torque, when backlash is present in the gear train, vibration during driving of the motor and the sound of the tooth surfaces of the gears striking increase. In particular, when the first and second drive motors 47 and 48 are close to the image forming unit 23, there is a case where not only sound but also vibration causes an adverse effect on pitch unevenness in image formation.

  However, such a problem can be improved in the sheet conveying unit 25 by using the drive transmission device of the present invention.

  FIG. 14 is a perspective view showing the configuration of the drive unit of the sheet conveying unit 25 using the drive transmission device of the present invention.

  In FIG. 14, reference numeral 49 denotes a first paper feed roller pair for transporting a sheet transported from the paper feed cassette 43 (upper stage) to the registration roller 46, and includes a drive roller 49a and a pressure roller 49b. Reference numeral 50 denotes a second paper feed roller pair that is disposed below the first paper feed roller pair 49 and transports the sheet transported from the paper feed cassette 43 (lower stage) to the registration roller 46, and includes a driving roller 50a and a pressure roller. 50b. Reference numerals 51 to 54 and 54a denote conveyance guides for guiding the sheet conveyed from the sheet feeding cassette 43 and for restricting movement.

  55 and 56 are pinion gears which are drive gears (third gears) press-fitted into the rotation shaft portions of the first and second drive motors 47 and 48, and 57 and 58 are fixed to the shaft portions of the drive roller 49a and the drive roller 50a. And a drive gear that is a first gear that rotates integrally. A permanent magnet is fixed to the inner peripheral surfaces of the drive gears 57 and 58.

  59 and 60 are backlash removing gears which are second gears rotatably attached to the drive gears 57 and 58 in order to remove backlash. In this embodiment, the drive gears 57 and 58 and the backlash removal gears 59 and 60 are made of a polyacetal resin having good sliding properties, and the pinion gears 55 and 56 are engineering plastics represented by PPS or the like. It is made of resin.

  And the permanent magnet is being fixed to the internal peripheral surface of this backlash removal gear 59,60, and the phase is shifted and arrange | positioned with the permanent magnet provided in the drive gears 57,58. As a result, an urging force acts between the drive gears 57 and 58 and the backlash removal gears 59 and 60 in the rotational direction. Thereby, the rotation transmission error of the gears and the vibrations of the drive motors 47 and 48 transmitted directly to the pinion gears 55 and 56 can be reduced, and the vibrations of the gears or the transmission of noise can be reduced.

  As described above, in the present embodiment, by using the gear device of the present invention for the sheet conveying portion 25, vibration during gear driving can be reduced without impairing assembly workability, and a single gear component is also inexpensive. It is possible to provide a low-cost copying machine. In this embodiment, for the purpose of improving the sheet conveyance accuracy, the drive motors 47 and 48 are disposed independently of the pair of feed rollers 49 and 50, respectively, but a gear train is formed. Needless to say, the same drive motor can be used.

  In the present embodiment, the drive transmission device of the present invention is used for the sheet conveyance unit. However, the configuration of the present invention is adopted for the drive transmission device that transmits the driving force to the photosensitive drum that is the image carrier. However, the effect of the present invention can be exhibited.

  FIG. 15 is a diagram illustrating a configuration of an electronic camera including an image pickup device that is an image pickup device serving as a device according to a second example including the drive transmission device according to the present embodiment. In the present embodiment, the drive transmission device according to the present embodiment is used for the zoom drive unit of the camera barrel. 15A is a lens barrel sectional view at a so-called retracted position when not in use, and FIG. 15B is a lens barrel sectional view in an operating state.

  In FIG. 15, reference numeral 61 denotes a base that is a base portion of the lens barrel unit, which is fixed together with a fixed cylinder 62 and a cover 63 by screws or the like to form a structure of the lens barrel unit. Reference numeral 64 denotes a first lens barrel that holds the first lens 65, and a follower portion 64 a having a tapered portion at the tip is projected and formed on the outer peripheral side surface of the first lens barrel 64. An annular cap 66 is fixed to the front surface of the first lens barrel 64 by adhesion or the like.

  Reference numeral 67 denotes a second lens barrel that holds the second lens 68, and a follower portion 67 a having a tapered portion at the tip is projected from the outer peripheral side surface of the second lens barrel 67. Reference numeral 69 denotes a third lens barrel that holds the third lens 70, and is guided by the guide bar 71 so as to be movable in the optical axis direction. The axial position is provided on the arm portion 69 a, and the screw 72. It is regulated by a nut (not shown) that is rotatably engaged.

  The screw 72 is provided integrally with the magnet 73 and has a male screw portion that is screwed with a female screw portion of a nut (not shown) of the third barrel 69. One end of the screw 72 is rotatably fitted to the bearing 61 a of the base 61, and the other end is rotatably fitted to a cap 74 fixed to the base 61.

  A yoke 75 is disposed at a position facing the magnet 73, and generates a rotational driving force by energizing a coil (not shown). Reference numeral 76 denotes an LPF (low-pass filter) fixed to the base 61 by bonding or the like. Reference numeral 77 denotes an image sensor, which is fixed and held by a bonding or the like on a holding plate 78 fixed to the base 61 with screws. Reference numeral 79 denotes a PCB flex, which supplies an image signal photoelectrically converted by the image sensor 77 to a signal processing circuit (not shown).

  A drive ring 80 is rotatably fitted to the outer peripheral portion of the fixed cylinder 62, and a gear portion 80 a is formed in part on the outer peripheral portion of the drive ring 80. It is rotationally driven via 81 and a reduction gear 83. Further, in the gear portion 80 a of the drive ring 80, the moving cam ring 84 is fitted to the inner peripheral portion of the fixed cylinder 62, and the rectilinear guide cylinder 85 is further fitted to the inner circumference. A drive pin 86 is press-fitted and fixed to the outer peripheral portion of the moving cam ring 84, and a follower pin 87 having a taper portion protrudes from the outer peripheral portion of the moving cam ring 84.

  The drive pin 86 is fitted in a groove portion 80 b provided on the inner peripheral side of the drive ring 80 through the hole portion 62 a of the fixed cylinder 62. Further, the follower pin 87 is in sliding contact with a tapered cam groove 62 b provided on the inner periphery of the fixed cylinder 62 at the tip tapered portion.

  In such a configuration, when the drive ring 80 is rotationally driven, the moving cam ring 84 also moves in the optical axis direction while rotating along the tapered cam groove 62 b of the fixed cylinder 62 via the drive pin 86. At this time, the rectilinear guide cylinder 85 moves only in the optical axis direction following the movement of the movable cam ring 84 in the optical axis direction.

  The first lens barrel 64 and the second lens barrel 67 move in the optical axis direction with the relative movement of the moving cam ring 84 and the rectilinear guide tube 85 via the respective follower portions 64a and 67a. Along with this cam trajectory, it is configured to carry out a use state and a zooming operation.

  Here, in the present embodiment, the drive transmission device of the present invention is used for a gear device including a gear portion 80a that is a drive gear and a reduction gear 83 that is rotated by the gear portion 80a. That is, in this embodiment, the speed reduction gear 83 is composed of two gears as shown in FIGS. 1 and 10 and the like, so that backlash at the time of meshing with the gears is eliminated, and at the time of driving. The generated vibration is reduced.

  In this embodiment, as for the gear material, the material of the gear portion 80a is formed of a polyacetal resin having a good slidability as in the first embodiment. Further, the material of the reduction gear 83 (drive side gear and backlash removal gear) on the motor shaft side is formed of engineering plastics resin represented by PPS or the like. Thereby, the rotation transmission error of the gear and the motor vibration transmitted directly to the reduction gear 83 of the motor shaft are reduced, and the transmission of gear vibration or noise is reduced.

  With the above configuration, the biasing force from the rotation axis direction by the spring as the biasing means can be efficiently converted into the rotation force of the movable gear, and the force received from the tooth surface can be uniformly distributed as a rotation force over the entire gear. Therefore, it is possible to smoothly follow the backlash fluctuation of the meshing gear. As a result, play due to gear machining errors can be absorbed, tooth surface irregularities can be reduced, and highly accurate rotation transmission and noise reduction can be achieved.

  Further, in the conventional example (FIG. 18), since the contact surface (sliding surface) according to the number of teeth is provided, the friction during the rotation of the movable gear increases. However, in the present invention, it is possible to reduce the frictional force by providing a substantially semi-cylindrical or substantially hemispherical projection on the contact area on at least one of the inclined surfaces provided on the fixed gear or the movable gear. The degree of freedom is also widened.

  Furthermore, by setting the angle of the inclined surfaces provided on the fixed side gear and the movable side gear within the range of 35 to 55 deg, it is possible to efficiently convert the urging force in the rotational axis direction by the spring to the rotational force of the movable side gear. it can. Furthermore, by forming the material of the movable gear from a flexible resin, it is possible to integrally form an elastically deformable arm on the side surface of the movable gear or insert-mold a metal leaf spring or the like. As a result, the backlash between the gears can be reduced with a simple configuration without requiring a spring member as a separate part.

  Furthermore, according to the present invention, since the number of parts of the drive motor and the gear train can be increased and the assembly can be performed with simpler work than before even during assembly, a stable device can be supplied.

1, 7 First gear 2, 8 Second gear 1 (a), 2 (a) Gear tooth surface 1 (b), 2 (b) Cylindrical portion 1 (c), 2 (c) Inclined surface 1 (f ) Roughly semi-cylindrical ridge 1 (g) Roughly hemispherical protrusion 3, 9 Rotating shaft 4 Retaining ring 5 Compression coil spring 6, 11 Thrust receiving plate 10 Thrust leaf spring 10 (a) Positioning hole 10 (b) Arm Part 10 (c) Projection part 20 Copying machine 25 Sheet conveying part 47, 48 First and second drive motor 55, 56 Pinion gear 57, 58 Drive gear 59, 60 Backlash removal gear 80 (a) Gear part 83 Reduction gear

Claims (4)

A rotatable rotating shaft, a first gear attached to the rotating shaft and rotating integrally with the rotating shaft, a second gear attached to the rotating shaft and rotatable with respect to the rotating shaft; A third gear disposed to mesh with one gear and the second gear and forming a drive transmission path; and provided on an inner surface of the first gear facing the second gear; A coupling mechanism provided with a first coupling portion and an inner surface of the second gear facing the first gear for coupling the two gears, and a second coupling portion coupled with the first coupling portion; A drive transmission mechanism having
Biasing means for applying a biasing force from the outer surface side of at least one gear of the first gear or the second gear toward the other gear, and at least of the first coupling part or the second coupling part One connecting portion is provided with an inclined surface, and the second gear biases the three gears in the rotation direction of the second gear by contacting the inclined surface with the other connecting portion. Transmission mechanism.   The drive transmission mechanism according to claim 1, wherein a second inclined surface is provided on the other connecting portion that contacts the inclined surface.   The drive transmission mechanism according to claim 1, wherein a plurality of the inclined surfaces are provided in a rotation direction of the rotation shaft.   The said 1st connection part has a cylindrical part, The said inclined surface is formed so that it may become perpendicular | vertical with respect to the surface of a cylindrical part, The Claim 1 characterized by the above-mentioned. Drive transmission mechanism.

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