JP4056174B2 - Drive unit gear retaining structure, image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear retaining structure for a drive unit suitable for use in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, or a complex machine thereof.
[0002]
[Prior art]
In this type of conventional drive unit, a gear train composed of a plurality of gears rotatably mounted on a fixed shaft standing on a plate-like member (hereinafter referred to as a side plate) is provided, and an E-ring or the like is provided on the fixed shaft. Either a retaining ring was attached or another side plate was prepared, and the gear train was fixed between the two side plates. Examples of the latter include those disclosed in Japanese Patent Application Laid-Open No. 8-248717, which eliminates a retaining ring such as an E ring in order to improve recyclability (ease of disassembly), or a drive unit for cost reduction. One of the side plates forms the structure of the machine body and has a function of supporting one end of the fixed shaft.
[0003]
9 and 10 show a configuration similar to the drive unit disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-248717, and a plurality of fixed shafts 2... Are provided integrally with the housing 1 which is a resin side plate. Each of the fixed shafts 2 is mounted with a plurality of gears 3 constituting a gear train and attached to the machine body 4 in that state. On the machine body 4 side, a plurality of bosses 5... For immersing the tip of the fixed shaft 2 are provided.
[0004]
[Problems to be solved by the invention]
In such a drive unit, since the retaining ring such as the E-ring is eliminated as described above, when the fixed shaft 2 is leveled when the housing 1 to which the gear 3 is attached is assembled to the machine body 4, the gear 3 is The fixed shaft 2 may fall off. In order to prevent this, the assembling work must be performed while holding the gear 3 so that it does not fall off, so the workability is very poor.
[0005]
Therefore, providing a snap-fit groove on the fixed shaft 2 (see, for example, Japanese Patent Laid-Open No. 10-226439) increases the cost of the mold structure and increases the processing accuracy of the shaft. There is a defect, and it is necessary to take measures against wear against the thrust load.
[0006]
Accordingly, an object of the present invention is to provide a drive unit gear retaining structure that eliminates these conventional problems and is inexpensive and excellent in recyclability.
[0007]
[Means for Solving the Problems]
In the drive unit gear retaining structure according to the first aspect of the present invention, in order to achieve the above object, a gear for transmitting a driving force to a fixed shaft standing on a plate-like member is rotatable. attached to, with the gear retaining structure of the drive unit gears that該装dressed to retained from the fixed shaft, Rutotomoni provided claw-like projections on the plate-like member, said gear flange, the pawl on the collar A notch that can be inserted into the nail portion of the projection is provided, the size of the notch is larger than the area through which the nail portion passes, and the nail portion is inserted into the notch and passes therethrough. is allowed to rotate the gear after issuing the claw portion on said collar, said claw portion is characterized that you allow retained by pressing from above said flange.
[0008]
According to the second aspect of the present invention, there is provided a drive unit that rotatably mounts a gear for transmitting a driving force on a fixed shaft standing on a plate-like member and prevents the mounted gear from coming off from the fixed shaft. In the gear retaining structure, the plate-like member is provided with a claw-like protrusion, the gear is provided with a collar, and a notch into which the claw portion of the claw-like protrusion can be inserted is provided on the collar, and the size of the notch Is made larger than the region through which the claw portion passes .
[0009]
Those according to the third aspect, in the lack Ri upper SL switch of the one field, providing the stopper portion is elastically deformable protrusion, and by deforming the stopper portion by inserting the claw portion away the cut The stopper is restored after passing the claw and protruding the claw on the collar, so that it does not come out even if the notch of the collar matches the claw .
[0010]
Those according to the fourth aspect, the gear is a helical gear having a twist angle which can exert a thrust load to the plate-like member, constitutes a gear train meshed with seeing other gear to the helical gear, to the plate-like member side thrust load of the helical gear is characterized by being configured to act.
[0011]
The image forming apparatus according to claim 5 is characterized in that the drive unit gear retaining structure according to any one of claims 1 to 4 is used .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing a first embodiment of a drive unit gear retaining structure according to the present invention. In the figure, reference numeral 10 denotes a resin plate-like side plate. A fixed shaft 11 is erected on the side plate 10, and a space for inserting a gear 12 is provided around the fixed shaft 11 to form a claw-like projection. 13 is also erected. The fixed shaft 11 and the claw-like projection 13 are integrally formed with the side plate 10, and the claw-like projection 13 can be elastically deformed as indicated by a two-dot chain line in the figure.
[0013]
For this reason, when the gear 12 is to be attached to the fixed shaft 11, the claw-like projections 13 are elastically deformed as shown in the figure so as not to obstruct the attachment, and the claw portions 13a of the claw-like projections 13 are attached after the attachment. Is positioned so as to be positioned on the peripheral edge of the gear 12 so as to serve as a stopper against dropping of the gear 12.
[0014]
For example, the side plate 10 is made of metal and the claw-like projection 13 is made of SUS or resin, or the SUS-made claw-like projection 13 is formed on the resin side plate 10 without integrally forming the side plate 10 and the claw-like projection 13. It does not matter as a separate body such as assembling.
[0015]
FIG. 2 is a cross-sectional view showing a second embodiment of the present invention. The gear retaining structure of the present embodiment is basically the same as that of the first embodiment of the present invention shown in FIG. 1 except that a collar 12a is provided on the gear 12 and the claws are attached to the fixed shaft 11. The claw portion 13a of the projection 13 is returned so as to be positioned on the collar 12a of the gear 12 so as to serve as a stopper against dropping of the gear 12. The gear 12 and the collar 12a may be formed by integral molding of resin or the like. Other configurations, attachment operations, and the like are the same as those in the previous embodiment, and thus description thereof is omitted.
[0016]
FIG. 3 is a cross-sectional view showing a third embodiment of the present invention. The gear retaining structure of this embodiment is basically the same as that of the first embodiment of the present invention shown in FIG. 1, but is an example applied to a gear train including a two-stage gear. That is, the two-stage gears 14 and 14 are attached to the two fixed shafts 11 and 11 erected on the side plate 10 in the opposite directions as shown in the drawing, and the claw-like projections 13 are attached to the one two-stage gear 14. Is provided to prevent the claw portion 13a from coming off. Of course, claw-like protrusions may be provided for the remaining two-stage gear 14. Other configurations, attachment operations, and the like are the same as those in the previous embodiment, and thus description thereof is omitted.
[0017]
FIG. 4 is a cross-sectional view showing a fourth embodiment of the present invention, and FIG. 5 is a plan view thereof. The present embodiment takes into consideration that the gear tooth surfaces may be damaged when the gears 12 and 14 are inserted into the fixed shaft 11 in the structures of the first and third embodiments described above. . That is, in the present embodiment, a collar 16 is provided on the gear 15 and a notch 17 is formed in the collar 16 so that the notch 17 of the collar 16 and the claw portion 18a of the claw-shaped protrusion 18 are aligned as can be seen from FIG. The gear 15 is attached to the fixed shaft 11. After the insertion, the gear 15 is rotated so that the claw portion 18a of the claw-shaped projection 18 presses the collar 16 of the gear 15 from above to prevent it from coming off. In this way, the claw-shaped protrusion 18 does not damage the tooth surface of the gear 15. Other configurations, attachment operations, and the like are the same as those in the previous embodiment, and thus description thereof is omitted.
[0018]
FIG. 6 is a cross-sectional view showing a fifth embodiment of the present invention. The gear retaining structure of the present embodiment is basically the same as that of the third embodiment of the present invention shown in FIGS. 4 and 5, but is an example applied to a gear train including a two-stage gear. . That is, a two-stage gear 20a with a collar 19 and a two-stage gear 20b without a collar are attached to two fixed shafts 11 and 11 erected on the side plate 10 in the opposite directions as shown in the figure. A claw-like projection 21 is provided on the collar 19 of the step gear 20a, and the claw portion 21a prevents the claw-like projection 21 from coming off. Although not shown, the collar 19 is provided with a notch. Of course, it is also possible to form hooks on the remaining two-stage gear 20b and to provide claw-like projections. Other configurations, attachment operations, and the like are the same as those in the previous embodiment, and thus description thereof is omitted.
[0019]
In the fifth embodiment, if a helical gear is used for the two-stage gears 20a and 20b as in the device disclosed in Japanese Patent Laid-Open No. 10-226439, a thrust load is applied, and the thrust load is directed toward the claw portion 21a of the claw-shaped protrusion 21. When operated in the upward direction (in the figure), the gap between the claw-shaped projection 21 and the collar 19 (in the case of a gear without a collar, the peripheral edge of the upper surface of the gear) becomes small, so that the collar 19 and the claw 21a are moved when the gear rotates. There is a risk that it will come into constant contact. Therefore, when the helical gear is used, the flanged two-stage gear 20a may be a helical gear having a helix angle that applies a load in the direction of the side plate 10.
[0020]
FIG. 7 is a plan view showing a sixth embodiment of the present invention. In the present embodiment, in the structures of the fourth and fifth embodiments described above, the notches 17 provided on the collars 16 and 19 and the claw portions 18a and 21a of the claw-shaped projections 18 and 21 are very rarely coincident with each other. Therefore, the gears 15 and 20a may come off from the fixed shaft 11 when assembled. That is, in this embodiment, the notch 24 formed in the collar 23 of the gear 22 is provided with a cantilevered elastically deformable locking piece 25 as shown in the figure as a stopper, and the gear 22 is mounted on the fixed shaft 11. At this time, the locking piece portion 25 is deformed and assembled, and the locking piece portion 25 is restored after the mounting, so that the notch 24 of the collar 23 and the claw portion of the claw-shaped projection (not shown) do not come out. It is. In this case, if the gear 22 is made of metal, the collar 23 may be made of a leaf spring material such as SUS and attached to the metal gear by caulking. Further, the gear 22 and the collar 23 may be integrally formed with resin.
[0021]
FIG. 8 is a plan view showing a modification of the sixth embodiment of the present invention shown in FIG. In this embodiment, a leaf spring 26 is partially attached to the collar 23 of the gear 22 to form a locking side portion.
In other words, even if the plate member is tilted after the gear is mounted on the fixed shaft standing on the plate member, the gear does not fall off the fixed shaft, and an element part having a complicated shape and structure is required. Therefore, it is possible to realize an inexpensive and highly recyclable structure.
Further, by using the collar provided on the gear, the gear can be mounted on the fixed shaft of the plate member without damaging the tooth surface of the gear.
Furthermore, since the stopper part protruded to the gear notch is elastically deformed, the gear does not fall off the fixed shaft even if the notch of the gear and the claw part of the claw-shaped protrusion coincide after the gear is mounted.
Furthermore, since the thrust load of the gear is arranged on the plate-like member side, the gear tooth surface and the collar and the claw portion of the claw-like projection do not come into contact after the gear is assembled to the fixed shaft.
[0022]
【The invention's effect】
As described above , the drive unit gear retaining structure and the image forming apparatus using the same according to the present invention use the collar provided on the gear so that the gear does not fall off the fixed shaft and is complicated. shape, since it does not require an structural element parts, inexpensive can achieve excellent structural recyclability on to enable mounting the gear on the fixed shaft of without plate member damaging the tooth surface of the gear There is an effect of becoming.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a gear retaining structure of a drive unit according to the present invention.
FIG. 2 is a cross-sectional view showing a second embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a third embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a fourth embodiment of the present invention.
FIG. 5 is a plan view of the same.
FIG. 6 is a cross-sectional view showing a fifth embodiment of the present invention.
FIG. 7 is a plan view showing a sixth embodiment of the present invention.
FIG. 8 is a plan view showing a modification of the sixth embodiment of the present invention.
FIG. 9 is a perspective view showing an example of a gear retaining structure of a conventional drive unit.
FIG. 10 is an exploded perspective view showing attachment to the machine body.
[Explanation of symbols]
10 side plate 11 fixed shaft 12 gear 12a collar 13 claw-like projection 13a claw part 14 second gear 15 gear 16 collar 17 notch 18 claw-like projection 18a claw part 19 collar 20a, 20b two-stage gear 21 claw-like protrusion 21a claw part 22 Gear 23 collar 24 notch 25 locking piece 26 leaf spring

Claims (5)

  A drive unit gear retaining structure in which a gear for transmitting a driving force is rotatably mounted on a fixed shaft standing on a plate-shaped member, and the mounted gear is prevented from being detached from the fixed shaft. A claw-like projection is provided on the member, and the gear is provided with a collar. The collar is provided with a notch that can be inserted into the claw-like projection, and the claw-like projection is inserted into the collar. The claw portion is inserted into the notch and passed therethrough, the claw portion is put out on the collar, the gear is rotated, and the claw portion lifts the collar from above. A drive unit gear retaining structure characterized in that it can be retained by holding it down.   A drive unit gear retaining structure in which a gear for transmitting a driving force is rotatably mounted on a fixed shaft standing on a plate-shaped member, and the mounted gear is prevented from being detached from the fixed shaft. A claw-like protrusion is provided on the member, the gear is provided with a collar, a notch into which the claw part of the claw-like protrusion can be inserted is provided in the collar, and the size of the notch is determined from an area through which the claw part passes The structure of the drive unit that prevents the gear from coming off.   A stopper portion protruding in an elastically deformable manner is provided in the notch of the collar, the stopper portion is deformed and the claw portion is inserted and passed through the notch, and the claw portion is placed on the collar. 3. The drive unit gear retaining structure according to claim 1 or 2, wherein the stopper portion is restored after being released so that the collar notch does not come out even if the notch of the collar coincides with the claw portion. The gear is a helical gear having a twist angle which can exert a thrust load to the plate-like member, it constitutes a gear train meshed with seeing other gear to the helical gear, the helical gear to the plate-like member side The drive unit gear retaining structure according to any one of claims 1 to 3, wherein a thrust load is applied to the drive unit.   An image forming apparatus using the gear retaining structure of the drive unit according to claim 1.

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