JP2004360923A - Method of application of reduction gear made of resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of application of a reduction gear made of resin with high transmitting precision of rotation. <P>SOLUTION: In this resin gear 1, the first and the second circumferential ribs 10 and 12 are constituted concentrically with a web 5 in a inner circumferential side of teeth 8. This web 5 is increased in its rigidity by a diametrical ribs 14, 12 and 15. the diametrical rib 14 is constituted to extend diagonally to a reverse direction of a rotational direction. This resin gear 1 is used to cause such a resistance as to stop a displacement in the diametric rib 11 to tend to cause slipping displacement to the rotational direction from a shaft support 4 by a torque fluctuation which works in case of transmitting the rotation. So this construction can effectively control the slipping displacement of the second circumferential rib 11 to the rotational direction from the shaft support 4 and control a deviation of rotational angular speed between the second circumferential rib 11 and the shaft support, and a deviation of rotational angular speed of the teeth 8 and the shaft support 4 as a result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of using a resin gear widely used for a power transmission mechanism of a copier, a printer, a facsimile, an automobile part, and the like.

  2. Description of the Related Art Conventionally, resin gears have been used in power transmission mechanisms of copying machines, automobile parts, and the like for the purpose of reducing the cost of parts, reducing the weight, and reducing operating noise. This resin gear is formed into a predetermined shape by injection molding, and the shape is devised so that the tooth profile accuracy and strength match the intended use.

  For example, in an image forming apparatus such as a color copying machine, a resin helical gear having a high meshing ratio is used as a resin gear for driving the photoconductor in order to create a clear high-quality color image. The shape of the resin helical gear is variously devised. The resin helical gear is connected to a photoconductor driving motor (driving means), and the rotational force of the photoconductor driving motor is smoothly transmitted to the photoconductor via the resin helical gear. By rotating the photoconductor smoothly and with high precision, printing defects such as color misregistration are effectively prevented (see Non-Patent Document 1).

  FIGS. 16 and 17 show a resin helical gear 100 used in such an image forming apparatus. The resin helical gear 100 shown in these figures has a shaft support portion 103 having a shaft hole 102 fitted so as to be able to rotate integrally with a photoconductor drive shaft 101, and a radial direction of the shaft support portion 103. It has a rim 105 with teeth 104 located on the outside and a thin web 106 connecting the shaft support 103 and the rim 105. The resin helical gear 100 has annular first and second circumferential ribs 107, 108 inside the rim 105 and on both side surfaces of the web 106 in order to prevent deformation of the web 106 due to a thrust load. Are formed, radial ribs 110 connected to the shaft support 103 and the second circumferential rib 108 are formed radially on both side surfaces of the web 106 between the shaft support 103 and the second circumferential rib 108, Radial ribs 111 connected to the first circumferential rib 107 and the second circumferential rib 108 are formed radially on both side surfaces of the web 106 between the first circumferential rib 107 and the second circumferential rib 108. Have been.

  In the resin helical gear 100 having such a configuration, since the radial ribs 110 and 111 are not connected to the rim 105, the rigidity of the web 106 is maintained without impairing the roundness of the rim 105 having the teeth 104. Can be increased. Since the resin helical gear 100 is formed into the shape shown in FIGS. 16 and 17 by injection molding, the thicker the resin, the longer the cooling in the cavity takes. The amount of shrinkage deformation increases. Therefore, in the resin helical gear 100 having such a shape, when the thickness of the web 106 is large, the thickness of the connecting portion between the web 106 and the rim 105 is large, and the radius of the connecting portion between the web 106 and the rim 105 is large. Since the amount of contraction deformation inward in the direction becomes larger than that of the other portion of the rim 105, the tooth profile accuracy is deteriorated. Also, as shown in FIG. 18, when the radial rib 112 is connected to the rim 113, the thickness of the connecting portion between the radial rib 112 and the rim 113 is increased, and the connection between the radial rib 112 and the rim 113 is increased. The amount of contraction deformation of the portion inward in the radial direction is larger than that of the other portion of the rim 113 (see the dotted line portion in the figure), and the roundness is reduced. Therefore, in the conventional resin helical gear 100 shown in FIGS. 16 and 17, the thickness of the web 106 is made as thin as possible so that the accuracy of the teeth 104 becomes a desired accuracy, and the rigidity of the web 106 is increased. Are compensated by the first and second circumferential ribs 107 and 108 and the radial ribs 110 and 111.

Japan Society of Precision Engineering, Plastic Plastic Gear Research Special Edition, “Molded Plastic Gear Handbook”, Sigma Publishing, April 20, 1995, pp. 477-478.

  2. Description of the Related Art In recent years, image forming apparatuses such as color printers and color copiers have been required to be able to perform more vivid color printing than conventional examples with the development of image processing technology. In order to meet such a demand, it is necessary to rotate the photoconductor more smoothly and with higher precision than before, and to improve the accuracy of image formation on the photoconductor. Here, it is the accuracy of the resin helical gear that greatly affects the rotation accuracy of the photoconductor, as described above.

  However, as shown in FIG. 19, the conventional resin helical gear 100 is deformed such that the rim 105 having the teeth 104 is displaced in the rotational direction with respect to the shaft support 103 by a torque acting upon power transmission. However, in particular, the deformation between the shaft support portion 103 and the second circumferential rib 108 is larger than that of the other portions, and the radial rib 110 formed on the outer peripheral side of the shaft support portion 103 is deformed as indicated by a dotted line. Therefore, there is a difference between the rotation transmitted from the photoconductor driving motor (not shown) to the resin helical gear 100 and the rotation transmitted from the resin helical gear 100 to the photoconductor driving shaft 101, and this rotation is generated. It has been found that such a shift causes a reduction in image quality such as a color shift.

  Therefore, an object of the present invention is to improve the dynamic accuracy (rotation transmission accuracy) of the resin gear by devising the shape of the resin gear and the method of using the same.

  According to the first aspect of the present invention, a substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to center on the rotation center of the tooth portion, and the shaft The present invention relates to a method of using a resin gear provided with a thin plate-shaped web for connecting a supporting portion and the tooth portion. In the present invention, the resin gear forms a circumferential rib on the web inside the tooth portion and at a position concentric with the tooth portion, and a plurality of the gears are formed obliquely outward from the outer periphery of the shaft support portion. The circumferential ribs and the shaft supporting portion are connected along the side surface of the web by the radial ribs, and the connecting portion between the radial ribs and the circumferential rib is the radial rib. With respect to a line connecting the connection portion of the shaft support portion and the rotation center, it is arranged so as to be located on the side opposite to the rotation direction side so that the radial rib receives a compressive force at the time of power transmission. Used.

  A second aspect of the present invention provides a substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to center on the rotation center of the tooth portion, The present invention relates to a method of using a resin gear provided with a thin plate-shaped web for connecting a supporting portion and the tooth portion. In the present invention, the resin gear connects the shaft support portion and the tooth portion along a side surface of the web by a plurality of radial ribs formed obliquely outward from the outer periphery of the shaft support portion. And the radial ribs are used to receive a compressive force during power transmission.

  As described above, according to the method of using the resin gear of the present invention, since the radial rib is used so as to receive a compressive force at the start of power transmission, the tooth portion is rotated by the torque fluctuation at the time of transmitting the rotation so that the shaft supporting portion is used. When the radial rib is displaced in the rotational direction, a resistive force is generated in the radial rib to prevent the displacement, and the tooth portion is displaced in the rotational direction with respect to the shaft support. And a variation in the rotational angular velocity between the tooth portion and the shaft support portion can be suppressed. Therefore, according to the method of using the resin gear of the present invention, smooth and highly accurate rotation transmission is possible.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(Resin helical gear)
[First Embodiment]
1 to 3 show a resin helical gear 1 as a resin gear according to a first embodiment of the present invention. FIG. 1 is a front view (left side view of FIG. 2) of the resin helical gear 1. FIG. 2 is a cross-sectional view of the resin helical gear 1 cut along the line AA in FIG. FIG. 3 is a rear view (a right side view of FIG. 2) of the resin helical gear 1.

  As shown in these figures, the resin helical gear 1 is injection-molded using a resin material such as polyacetal or fluorine-added polycarbonate, and has a shaft hole engaged with the photoconductor drive shaft 2. A shaft support 4 on which a shaft 3 is formed, a web 5 formed substantially at the center in the axial direction of the shaft support 4 and on the outer surface of the shaft support 4, and connected to the shaft support 4 by the web 5 And a substantially annular rim 6 to be formed. Further, teeth 7 are formed on the outer peripheral side of the rim 6 formed concentrically with the shaft support 4. The rim 6 and the teeth 7 form a substantially cylindrical tooth portion 8.

  Inside the rim 6 and on both side surfaces of the web 5, annular first circumferential ribs 10 concentric with the rim 6 are formed, respectively. Further, between the first circumferential rib 10 and the shaft supporting portion 4 and on both side surfaces of the web 5, annular second circumferential ribs 11 concentric with the first circumferential rib 10 are respectively provided. Is formed. A plurality of first circumferential ribs 10 and a plurality of second circumferential ribs 11 are formed radially on both side surfaces of the web 5 between the first circumferential rib 10 and the second circumferential rib 11. Are connected by the radial ribs 12 provided.

  The cylindrical outer cylindrical portion 13 of the second circumferential rib 11 and the shaft support 4 is formed on both sides of the web 5 between the second circumferential rib 11 and the outer cylindrical portion 13 of the shaft support 4. They are connected by a plurality of radial ribs 14 respectively formed on the surfaces. The radial rib 14 connecting the second circumferential rib 11 and the outer cylindrical portion 13 of the shaft support 4 is formed so as to be inclined in a direction opposite to the rotation direction of the resin helical gear 1. When a force in the clockwise direction in FIG. 1 acts on the teeth (at the start of power transmission), it receives a compressive force to prevent the relative rotation between the second circumferential rib 11 and the shaft support 4. Is caused.

  On both side surfaces of the web 5 between the first circumferential rib 10 and the rim 6, radial ribs 15 having a width and a height that do not adversely affect the tooth profile accuracy are provided. And a plurality of rims 6 are formed radially so as to connect the rim 6 to the rim 6. As a result, the rigidity of the web 5 between the first circumferential rib 10 and the rim 6 is increased by the plurality of radial ribs 15. The radial rib 15 has a smaller width W and a smaller height H than the other radial ribs 12 and 14.

  Here, the radial ribs 12, 14, 15 are formed so as to be shifted in the circumferential direction. That is, the outer peripheral end of the radial rib 14 is connected between the connecting portions of the second circumferential rib 11 and the radial ribs 12, 12, and the connection between the first circumferential rib 10 and the radial ribs 15, 15. The outer peripheral end of the radial rib 12 is connected between the portions. This is because, when the radial ribs 14, 12, 15 are located on the same straight line, the amount of contraction in the radial direction after the injection molding is increased, which may adversely affect the roundness of the tooth portion 8. Because. The circumferential ribs 10 and 11 and the radial ribs 12, 14 and 15 are formed at symmetrical positions on both side surfaces of the web 5. It is devised so as not to shift on the other side of the web 5 and to enable high-precision injection molding.

  The shaft support portion 4 includes an inner cylindrical portion 16 having a shaft hole 3 fitted to a photoconductor driving shaft 2 extending from a photoconductor (not shown), and an outer cylindrical portion formed concentrically with the inner cylindrical portion 16. The outer cylindrical portion 13 and the inner cylindrical portion 16 are connected by a web 17. On one side (left side in FIG. 2) of the web 17, a key groove 20 that engages with the rotation stop of the photoconductor drive shaft 2 is formed in a substantially cross shape. On one side surface of the web 5, a radial rib 21 for connecting the inner cylindrical portion 16 and the outer cylindrical portion 13 in the radial direction is formed between the respective key grooves 20 and 20. A circumferential rib 22 intersecting with the rib 21 is formed between each keyway 20. On the other hand, on the other side surface (the right side in FIG. 2) of the web 5 of the shaft support portion 4, a radial rib 23 connecting the inner cylindrical portion 16 and the outer cylindrical portion 13 in the radial direction is provided with a resin helical gear. 1 is formed so as to be inclined in a direction opposite to the rotation direction. A circumferential rib 24 intersecting with the plurality of radial ribs 23 is formed on the other side surface of the web 17 of the shaft support 4. Here, the outer peripheral end of the radial rib 23 is connected to the outer cylindrical portion 13 so as to be located between the inner peripheral ends of the radial ribs 14 on the radially outer side. This is because when the outer peripheral end position of the radial rib 23 and the inner peripheral end position of the radial rib 14 are formed so as to overlap with each other, the connection between the radial ribs 23 and 14 and the outer cylindrical portion 13 is larger than other portions. This is because the thickness becomes thick, and a difference occurs in the cooling rate after the injection molding, so that high-precision molding becomes difficult. As shown in FIG. 2, the web 17 of the shaft support 4 is formed at a position closer to one side surface where the key groove 20 is formed. This is because the rotation stopper 18 of the photoconductor drive shaft 2 is engaged with the key groove 20 of the shaft support portion 4 and a large torque acts on one side surface of the shaft support portion 4. This is because it is necessary to ensure the strength of one side surface of the portion 4.

  In the resin helical gear 1 having the above structure, the rim 6, the webs 5, 17, the circumferential ribs 10, 11, the outer cylindrical portion 13, and the inner cylindrical portion 16 are formed to have substantially the same thickness. The thickness of the radial ribs 12, 14, 21, 23 is formed to be equal to or smaller than the thickness of the circumferential ribs 10, 11 so that the cooling rate after injection molding is substantially the same in each part. Due to the configuration, the shrinkage and deformation after injection molding are made uniform, and molding is performed with high precision. The circumferential ribs 22 and 24 are formed to have substantially the same dimensions as the width and height of the radial rib 15, so that rigidity can be increased without impairing the molding accuracy of the shaft support 4. It is devised as follows.

  Further, since the resin helical gear 1 of the present embodiment is sufficiently thinned as described above, it is possible to reduce the weight, reduce the amount of shrinkage deformation after injection molding, and reduce the tooth portion. 8 can be formed with high precision. However, in the resin helical gear 1 of the present embodiment, the circumferential ribs 10, 11 and the radial ribs 12, 14, 15 are formed on the side surfaces of the web 5 even if the thickness is reduced as described above. As a result, since the web 5 is configured to ensure a sufficient strength, the rotational power input to the teeth 8 can be reliably transmitted to the photoconductor drive shaft 2 engaged with the shaft support 4. it can.

  In addition, the resin helical gear 1 of the present embodiment is provided between the second circumferential rib 11 and the shaft support 4 where the deformation in the rotational direction during rotation transmission is greatest (see FIG. 19). A radial rib 14 inclined in a direction opposite to the rotation direction is formed, and the radial rib 14 prevents the second circumferential rib 11 and the shaft support 4 from being displaced in the rotational direction. Since a force is generated, the amount of shift deformation (rotation phase difference) between the tooth portion 8 and the shaft support portion 4 in the rotation direction can be reduced. Therefore, according to the resin helical gear 1 of the present embodiment, the rotation transmission accuracy (dynamic accuracy) is improved, and the photoconductor drive shaft 2 can be rotated smoothly and with high accuracy. .

  In the above-described embodiment, the shape of each connection portion corner, such as the shape of the connection portion corner between the radial ribs 12 and 14 and the circumferential rib 11 and the shape of the connection portion corner between the radial rib 14 and the outer cylindrical portion 13, is described. , An R-shaped surface to improve moldability and releasability, and to avoid stress concentration.

  Further, in the resin helical gear 1 according to the above-described embodiment, the radial rib 12 between the first circumferential rib 10 and the second circumferential rib 11 is replaced with the second circumferential rib 11 and the shaft. Similar to the radial ribs 14 between the support portions 4, the resin helical gear 1 may be inclined in a direction opposite to the rotation direction. The resin helical gear 1 configured as described above can further improve the rotation transmission accuracy as compared with the above embodiment.

  Further, in the resin helical gear 1 according to the above-described embodiment, all of the radial ribs 12 and 15 are made of resin like the radial rib 14 between the second circumferential rib 11 and the shaft support 4. The helical gear 1 may be inclined in a direction opposite to the direction of rotation. The resin helical gear 1 configured as described above can further improve the rotation transmission accuracy as compared with the above embodiment.

  In the case where the resin helical gear 1 according to the above embodiment is used as an idle gear, only the radial rib 12 is provided in a direction opposite to the rotation direction of the resin helical gear 1. You may make it tilt.

  In addition, the resin helical gear 1 according to the above-described embodiment has been exemplified to be engaged with the photoconductor drive shaft 2 so as to be able to rotate integrally with the photosensitive member drive shaft 2, but the present invention is not limited to this. However, it can also be used in a mode in which it is rotatably engaged.

Further, in the above embodiment, the resin helical gear 1 that outputs the power input from the tooth portion 8 from the shaft support portion 4 has been illustrated, but the power input from the shaft support portion 4 is output from the tooth portion 8. The output resin helical gear 1 is formed such that the radial ribs 14 are inclined in the opposite direction to the radial ribs 14 of the above embodiment. That is, the resin helical gear 1 that outputs the power input from the shaft support 4 from the teeth 8 has the radial ribs 14 extending obliquely from the outer periphery of the shaft support 4 in the same direction as the rotation direction. A plurality is formed. The resin helical gear 1 formed in this manner has a reaction force such that the radial rib 14 receives a compressive force at the start of power transmission and prevents the shaft support 4 and the tooth 8 from moving in the rotational direction. And the same effect as in the above embodiment can be obtained. In addition, as described above, the resin helical gear 1 that outputs the power input from the shaft support portion 4 from the tooth portion 8 is formed by inclining the radial ribs 12 and 15 in the same direction as the radial rib 14. You may make it.
[Second Embodiment]
FIGS. 4 to 6 show a resin helical gear 31 according to a second embodiment of the present invention. The resin helical gear 31a, 31b having two large and small helical gears 31a and 31b is integrally formed. This shows a helical gear 31. FIG. 4 is a front view (left side view) of the resin helical gear 31. FIG. 5 is a sectional view taken along line BB of FIG. FIG. 6 is a rear view (a right side view of FIG. 5) of the resin helical gear 31.

  The resin helical gear 31 of the present embodiment has a first rim 33 having teeth 32 formed on the outer periphery, and a circle formed concentrically with the first rim 33 inside the first rim 33. An annular first circumferential rib 34, a second circumferential rib 35 formed concentrically with the first rim 33 inside the first circumferential rib 34, and a second circumferential rib 35 A rim 33, a first circumferential rib 34, and a second circumferential rib 35 are connected by a thin first web 37, The second circumferential rib 35 and the shaft support 36 are connected by a second thin plate-shaped web 38. The first circumferential rib 34 and the second circumferential rib 35 are formed to have the same dimensions (L1 = L2 = L3) as the tooth width (L1). The first web 37 is formed substantially at the center in the face width direction, and is formed so as to be orthogonal to the first rim 33, the first circumferential rib 34, and the second circumferential rib 35. I have. Also, the second web 38 has an outer peripheral end connected to the back side end (the right end in FIG. 5) of the second circumferential rib 35, and an inner peripheral end connected to the outer periphery of the shaft support 36. And is orthogonal to the second circumferential rib 35 and the shaft support portion 36. A second rim 41 having teeth 40 on the outer periphery is formed concentrically with the shaft support 36 on the back side surface of the second web 38. The first teeth 42 are formed by the teeth 32 and the first rim 33, and the second teeth 43 are formed by the teeth 40 and the second rim 41.

  On both sides of the first web 37 between the first rim 33 and the first circumferential rib 34, a radial direction connecting the first rim 33 and the first circumferential rib 34 in the radial direction is provided. A plurality of ribs 44 are formed in the circumferential direction. The first circumferential rib 34 and the second circumferential rib 35 are provided on both sides of the first web 37 between the first circumferential rib 34 and the second circumferential rib 35. A plurality of radial ribs 45 connected in the direction are formed in the circumferential direction. A radial rib connecting the second circumferential rib 35 and the shaft support 36 in the radial direction is provided on a side surface of the second web 38 between the second circumferential rib 35 and the shaft support 36. 46 are formed. Further, on a side surface of the second web 38 between the second rim 41 and the shaft support portion 36, a radial rib 47 for connecting the second rim 41 and the shaft support portion 36 in a radial direction is formed. ing. The shaft 50 is fitted into the shaft hole 48 of the shaft support 36 so that the shaft 50 can rotate integrally, or the shaft 50 is engaged so that the shaft 50 can rotate relatively.

  As shown in FIG. 4, the resin helical gear 31 of the present embodiment has radial ribs 44, 45, 46 formed on the surface side of the first and second webs 37, 38. The helical gear 31 is formed to be inclined in a direction opposite to the rotation direction of the gear 31. As a result, such a resin helical gear 31 causes the radial rib 44 to move when the first rim 33 side is displaced in the rotational direction with respect to the shaft support part 36 side by the torque acting during the transmission of the rotational power. , 45, and 46 are compressed toward the shaft support portion 36, and a reaction force for preventing the deformation is applied from the radial ribs 44, 45, and 46 to the first rim 33, the first circumferential rib 34, and the second It acts on the circumferential rib 35. Thereby, the resin helical gear 31 of the present embodiment prevents a phase difference from occurring between the rotation on the inner peripheral side (the shaft support portion 36 side) and the rotation on the outer peripheral side (the first rim 33 side). The rotation transmission accuracy (dynamic accuracy) can be improved.

  As shown in FIG. 6, the resin helical gear 31 of the present embodiment is configured such that the radial rib 47 connecting the second rim 41 and the shaft support 36 is inclined in the rotation direction. Is formed. As a result, in such a resin helical gear, the small-diameter helical gear 31b is meshed with another resin helical gear (not shown), and the small-diameter helical gear 31b is separated from the other resin helical gear. When the rotation is transmitted to the helical gear, torque acts on the second rim 41 in a direction opposite to the rotation direction, and the second rim 41 acts on the shaft support 36 in a direction opposite to the rotation direction. Even if the second rim 41 is to be displaced (displaced), a reaction force acting on the second rim 41 from the radial rib 47 to prevent the circumferential deformation of the second rim 41 is applied. As a result, the resin helical gear 31 of the present embodiment can suppress the occurrence of a phase difference between the rotation of the second rim 41 and the rotation of the shaft support portion 36, and the rotation transmission accuracy (dynamic accuracy) ) Can be improved.

  In addition, the resin helical gear 31 of the present embodiment includes a first rim 33, a first circumferential rib 34, a second circumferential rib 35, a shaft support 36, a second rim 41, and a second rim 41. The first and second webs 37 and 38 are formed so that the thicknesses thereof are substantially the same or approximately the same, and the thickness of the radial ribs 44, 45 and 46 is equal to the first and second circumferential ribs 34. , 35 and the first and second webs 37, 38 are formed thinner. The thickness of the radial rib 47 is smaller than the thickness of the second rim 41 and the shaft support 36. In addition, the radial ribs 44 connected to the first rim 33 are formed to have a height H and a thickness (width W) smaller than those of the other radial ribs 45 and 46, and the first tooth portion. The stiffness of the first web 37 is reinforced without adversely affecting the molding accuracy of the first web 37. Therefore, in the resin helical gear 31 of the present embodiment, the cooling rate after the injection molding is substantially the same in each part, the shrinkage deformation after the injection molding is uniform, and the molding is performed with high precision. Further, since the resin helical gear 31 of the present embodiment is sufficiently thinned as described above, the weight is reduced, and the amount of shrinkage deformation after injection molding is reduced. The whole shape including the second tooth portions 42 and 43 can be formed with high accuracy.

  As described above, the resin helical gear 31 of the present embodiment has excellent static accuracy (tooth profile accuracy) and dynamic accuracy (rotation transmission accuracy) similarly to the first embodiment. Since it is excellent, smooth and high-precision rotation transmission becomes possible.

In the resin helical gear 31 of the present embodiment, the thicknesses of the first web 37, the second circumferential rib 35, and the second web 38 are adjusted by the first rim 33 and the second rim 41. If the first web 37, the second circumferential rib 35 and the second web 38 are cooled faster than the first rim 33 and the second rim 41, Even if the cooling of the first rim 33 and the second rim 41 is delayed, the outer diameter of the large-diameter helical gear 31a and the small-diameter helical gear 31b due to the cooling after injection molding is reduced by the diameter reduction. It is possible to reduce the number, and to mold with higher precision.
[Third Embodiment]
7 and 8 show a resin helical gear 51 according to a third embodiment of the present invention. 7 is a front view of the resin helical gear 51, and FIG. 8 is a cross-sectional view cut along the line CC of FIG.

  The resin helical gear 51 shown in these figures has a smaller diameter than the resin helical gears 1 and 31 according to the first and second embodiments. As shown in FIG. 8, the resin helical gear 51 is formed in a symmetrical shape with respect to the central portion in the tooth width direction, and a shaft-supporting portion 52 and a rim 54 having teeth 53 are formed in a thin plate shape. Web 55. An annular circumferential rib 56 is formed inside the rim 54 concentrically with the rim 54, and radial ribs 57 are formed on both side surfaces of the web 55 between the circumferential rib 56 and the shaft support 52. I have. The radial rib 57 is formed so as to be inclined in a direction opposite to the rotational direction of the resin helical gear 51, and has an upper end connected to the circumferential rib 56 and a lower end connected to the shaft support 57. It is connected. The teeth 53 and the rim 54 form a tooth portion 58.

  Here, the rim 54, the circumferential rib 56, and the web 55 are formed with substantially the same thickness, and the thickness of the radial rib 57 is formed smaller than the thickness of the rim 54 and the like. Molded with high precision.

In the resin helical gear 51 having such a structure, the shaft hole 60 of the shaft supporting portion 52 is fitted to the shaft 59 so as to be integrally rotatable, and when transmitting the rotation to the shaft 59, the torque is applied from the outside. Although the rim 54 tends to move in the rotational direction with respect to the shaft support 52, the radial rib 57 stretches and resists, so that a phase difference occurs between the rotation of the rim 54 and the rotation of the shaft support 52. Can be suppressed. Therefore, the resin helical gear 51 of the present embodiment can transmit the rotation to the shaft 59 smoothly and with high precision.
[Fourth Embodiment]
9 and 10 show a resin helical gear 61 according to a fourth embodiment of the present invention. 9 is a front view of the resin helical gear 61, and FIG. 10 is a cross-sectional view taken along a line DD of FIG. Further, the resin helical gear 61 according to the present embodiment has a common configuration other than the resin helical gear 51 of the third embodiment, except for the radial rib 62, since the helical gear 61 has the same configuration. , The same components are denoted by the same reference numerals, and redundant description will be omitted.

  That is, the resin helical gear 61 shown in FIGS. 9 and 10 is used for transmitting rotation in both forward and reverse directions, and a substantially V-shaped radial rib 62 is formed as a circumferential rib 56. Formed on the side of the web 55 between the shaft support 52 and the ends of the substantially V-shaped radial ribs 62 are connected to the shaft support 55 and the circumferential rib 56, respectively, to increase the rigidity of the web 55. It has been improved. That is, the radial rib 62 includes a first radial rib 62 a formed so as to extend obliquely in a direction opposite to the normal rotation direction of the resin helical gear 61, and the reverse of the resin helical gear 61. The second radial rib 62b is formed to extend obliquely in the direction opposite to the rotation direction.

  The resin helical gear 61 having such a configuration transmits the rotation in both the forward and reverse directions to the shaft 59 fitted to the shaft hole 60 of the shaft support portion 52 so as to be integrally rotatable smoothly and with high precision. It becomes possible to do.

  As shown in FIGS. 11 to 12, the resin helical gear 61 has a substantially V-shaped radial rib 62 arranged more densely than in the embodiment shown in FIG. 9 to further increase the rigidity of the web 55. By increasing the rotation, smoother and more accurate rotation transmission can be achieved.

(Image forming device)
[Fifth Embodiment]
FIG. 13 shows a color copying machine (image forming apparatus) 70 in which the resin helical gears 1, 31, 51, 61 of the present invention are used.

  The image forming apparatus 70 shown in FIG. 1 feeds a sheet material 72 sent from a sheet feeding unit 71 between a photosensitive member 74 and a transfer roller 75 by a sheet conveying unit 73, and converts a color image formed on the photosensitive member 74 into a sheet. After the transfer to the sheet material 72, the sheet material 72 is fed between the fixing rollers 77a and 77b of the fixing unit 76 to fix the color image formed on the surface of the sheet material 72, and the sheet material 72 after the fixing operation is completed is discharged. The paper is discharged onto a paper discharge tray 80 by a pair of paper rollers.

  The photoreceptor 74 is configured to be rotated clockwise (in the direction of the arrow) in FIG. 13, and a cleaning unit 81, a discharging lamp 82, a charger 83, an exposure unit 84, and a color developing unit 85 are arranged around the photoreceptor 74. Have been. As shown in FIG. 14, for example, as shown in FIG. 14, the photoconductor drive shaft 2 fixed to the rotation center of the photoconductor drum 86 has the resin helical gears 1, 31, and A motor 87 as driving means connected to the shaft support portions 4, 36, 52 of the first and the second helical gears 1 (31, 51, 61) so as to be integrally rotatable. So that four color images of yellow (Y), magenta (M), cyan (C), and black (BK) of the color developing unit 85 are formed on the surface thereof in a superimposed manner. I have.

  In the image forming apparatus 70 having such a configuration, the rotation of the motor 87 is smoothly and accurately transmitted to the photoconductor 74 via the resin helical gear 1 (31, 51, 61). The fluctuation of the rotational angular velocity of the photoreceptor 74 is suppressed, the displacement of the color image of each color created on the photoreceptor 74 is suppressed, and a clear color image can be printed.

  In the above-described embodiment, the photosensitive drum 86 is exemplified as the photosensitive member 74. However, the present invention is not limited to this, and a photosensitive belt may be used as the photosensitive member 74. That is, as shown in FIG. 15, the resin helical gear 1 (31, 51, 61) according to each of the above embodiments is connected to the driving roller 90 of the photoreceptor belt 88 so as to be integrally rotatable. The gear (resin helical gear) 91 of the motor 87 meshes with the resin helical gear 1 (31, 51, 61), and the rotation of the motor 87 is controlled by the gear 91 and the resin helical gear 1 (31). , 51, 61) to the driving roller 90 to rotate the photosensitive belt 88 smoothly and with high precision. With such a configuration, the same effect as in the above embodiment can be obtained.

  Moreover, although the said embodiment illustrated the aspect which uses the resin helical gears 1 (31, 51, 61) based on each said embodiment for the drive of the photoreceptor 74, it is not restricted to this, As the driving gear or the idle gear for rotation transmission of the paper feeding roller 71a of the paper feeding unit 71, the registration roller 73a of the sheet conveying unit 73, the developing rollers 85a to 85d of the color developing unit 85, the fixing rollers 77a and 77b, etc. The resin helical gears 1, 31, 51, 61 according to the respective embodiments can be used as appropriate. Further, the present invention is not limited to the above-described embodiment, and in the case of an image forming apparatus (not shown) having a configuration using an intermediate transfer member, the resin-made thin film according to each of the above-described embodiments is used for driving the intermediate transfer member. Gears 1, 31, 51, 61 can be used.

  In addition, although the resin helical gears 1, 31, 51, and 61 according to the above embodiments are used in the image forming apparatus 70 such as a copying machine, a printer, and a facsimile as described above, The present invention is not limited to this, and can be widely applied to ink jet printers, automobile parts, other precision machines, and the like, and enables smooth and high-precision rotation transmission.

  Further, in each of the above embodiments, the resin helical gears 1, 31, 51, and 61 are exemplified as the resin gears. However, the present invention is not limited to this, and spur gears, bevel gears, worm gears, internal gears, and the like may be used. Can be widely applied to gears.

  Further, the present invention is not limited to gears, but can be applied to a resin pulley as a rotation transmission unit having teeth that mesh with the timing belt.

  Further, the resin helical gears 1, 31, 51, 61 according to the above embodiments are engaged with the shaft so as to be relatively rotatable, and transmit the rotation to other resin helical gears. Can be used for

It is a front view of the resin gear concerning a 1st embodiment of the present invention. It is sectional drawing which cut | disconnects and shows along the AA of the resin gear of FIG. FIG. 2 is a rear view of the resin gear according to the first embodiment of the present invention. It is a front view of the resin gear concerning a 2nd embodiment of the present invention. FIG. 5 is a cross-sectional view of the resin gear of FIG. 4 taken along line BB. It is a rear view of the resin gear concerning a 2nd embodiment of the present invention. It is a front view of the resin gear concerning a 3rd embodiment of the present invention. FIG. 8 is a cross-sectional view of the resin gear of FIG. 7 cut along line CC. It is a front view of the resin gear concerning a 4th embodiment of the present invention. It is sectional drawing which cut | disconnects and shows along the DD line of the resin gear of FIG. It is a figure of the resin gear which shows the example of application of 4th Embodiment. FIG. 11 (a) is a front view of the resin gear, and FIG. 11 (b) is a partially enlarged view of FIG. 11 (a). It is sectional drawing which cut | disconnects and shows along the EE line | wire of the resin gear of FIG. 11 (a). 1 is a schematic configuration diagram of an image forming apparatus. FIG. 3 is a diagram illustrating a drive mechanism of a photosensitive drum. FIG. 3 is a diagram illustrating a drive mechanism of a photoconductor belt. It is a front view of the conventional resin gear. FIG. 17 is a cross-sectional view of the resin gear of FIG. 16 cut along line FF. It is a front view of the resin gear which shows another conventional example. It is a deformation | transformation state figure which expands and shows a part of resin gear shown in FIG.

Explanation of symbols

  1,31,51,61 …… Resin helical gear (resin gear), 4,36,52 …… Shaft support, 5,37,38,55 …… Web, 8,42,43,58 ... tooth part, 10, 34 ... first circumferential rib, 11, 34 ... second circumferential rib, 12, 15, 45, 46, 57 ... radial rib, 56 ... circumferential rib 62 ... radial ribs, 62 a ... first radial ribs, 62 b ... second radial ribs

Claims (2)

A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to center on the rotation center of the tooth portion, and the shaft support portion and the tooth portion. In the method of using a resin gear comprising:
The resin gear,
A circumferential rib is formed on the web inside the tooth portion and concentric with the tooth portion, and the circumferential rib is formed by a plurality of radial ribs extending obliquely outward from the outer periphery of the shaft support portion. The shaft support is connected along the side of the web,
The connecting portion between the radial rib and the circumferential rib is located on a side opposite to the rotating direction side with respect to a line connecting the connecting portion between the radial rib and the shaft supporting portion and the rotation center. And the radial ribs are used to receive a compressive force during power transmission,
A method of using a resin gear, comprising: A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to center on the rotation center of the tooth portion, and the shaft support portion and the tooth portion. In the method of using a resin gear comprising:
The resin gear connects the shaft support portion and the tooth portion along a side surface of the web by a plurality of radial ribs formed obliquely outward from the outer periphery of the shaft support portion. Wherein the radial ribs are used to receive a compressive force during power transmission.
A method of using a resin gear, comprising:

Images