JP4522508B2 - Gear device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear device suitable for use in a recording apparatus such as a printer, a facsimile machine, and a copying machine, and more particularly to a resin gear apparatus.
[0002]
[Prior art]
Conventionally, a large number of gears are used in a recording apparatus such as a printer, and a resin gear held rotatably on a gear pin is also known. The gear pin for holding the gear is made of metal, and is fixed to the chassis in the recording apparatus by screwing or the like.
[0003]
[Problems to be solved by the invention]
However, metal gear pins are expensive and require attachment work to the chassis, leading to increased costs.
[0004]
Therefore, in order to reduce the cost of the gear pin, it is conceivable to make the gear pin integrally with the chassis by molding resin, and when this is carried out, it has been found that the following problems arise.
[0005]
In other words, when a gear pin is manufactured by molding a resin, the gear pin is made by removing it from the mold, so it is difficult to make the gear pin to have a constant diameter in the axial direction. 2A, the gear pin 2 formed integrally with the chassis 1 has a taper with a small diameter on the tip side. Similarly, the resin gear 3 has a taper in the pin insertion hole 4 for inserting a pin. The direction of the taper formed in the pin insertion hole 4 is set to coincide with the direction of the taper of the gear pin 2, and when the gear 3 is correctly attached to the gear pin 2, the taper of the hole of the gear pin 2 and the gear 3 is the same. The gear 3 is held on the gear pin 2 in a stable and rotatable manner. However, when the gear 3 is attached to the gear pin 2, the direction of the gear 3 may be reversed by mistake. In this case, too, the taper is small, so that the gear 3 is forcibly pushed as shown in FIG. As a result, the gear 3 is inserted to the base of the gear pin 2 and appears to be normally attached. However, in this case, the small diameter portion of the pin insertion hole 4 of the gear 3 enters the state where the gear pin 2 has a large diameter, so that when the gear 3 rotates, the gear 3 is rotated as indicated by an arrow. There has been a problem that the center shaft may rattle, and this may cause a load to lock the rotation of the gear.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and a gear device including a gear pin and a gear that does not cause a trouble due to an incorrect mounting direction when the resin gear is attached to the resin gear pin. The purpose is to provide.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is formed of a resin, a gear pin formed by combining a plurality of taper portions having different diameters and having a diameter that decreases toward the tip, and inserted into the gear pin. And a gear provided with a pin insertion hole having a plurality of taper portions corresponding to the formed taper portion of the gear pin, and the gear pin has a taper having a minimum outer diameter larger than a minimum inner diameter of the pin insertion hole. It has a part. If the taper of the pin insertion hole of the gear and the taper direction of the gear pin do not match with this configuration, even if the gear pin is inserted into the pin insertion hole of the gear, the gear stops halfway and is not inserted to the root. It can be seen that the direction is reversed, thus preventing reverse insertion of the gear and avoiding a situation where the gear locks during use.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment of the present invention, a gear pin formed of resin and formed by combining a plurality of taper portions having different diameters so that the diameter decreases toward the tip, and inserted into the gear pin and formed of resin. Provided with a pin insertion hole having a plurality of taper portions corresponding to the taper portion of the gear pin, and the gear pin has a taper portion having a minimum outer diameter larger than a minimum inner diameter of the pin insertion hole. It is equipped with. As described above, when the gear pin is provided with a tapered portion having a minimum outer diameter larger than the minimum inner diameter of the pin insertion hole, when the gear mounting direction with respect to the gear pin is reversed, the gear pin is moved to a predetermined position of the gear pin. Therefore, reverse insertion can be prevented, and the cost can be reduced by using a resin gear pin without any trouble.
[0009]
In another embodiment of the present invention, the gear pin is formed integrally with a chassis for a recording apparatus formed by resin molding. With this configuration, it is not necessary to attach the gear pins to the chassis, and the cost can be further reduced.
[0010]
Embodiments shown in the drawings will be described below. 1A is a schematic cross-sectional view showing a gear device according to an embodiment of the present invention in a state before assembly, and FIG. 1B is a schematic cross-sectional view showing the gear device in a state where a gear is correctly attached to a gear pin. FIG. 1 (c) is a schematic cross-sectional view showing the gear device in a state where the gear device is to be inserted in reverse on the gear pin. Reference numeral 11 denotes a chassis used in a recording apparatus such as a facsimile machine, and 12 denotes a gear pin formed integrally with the chassis 11. The chassis 11 and the gear pin 12 are integrally formed by resin molding, thereby reducing the cost. The gear pin 12 is formed with two-step tapered portions 12a and 12b whose diameter decreases toward the tip, and a step portion 12c is formed at the boundary between the two. The taper formed in each taper part 12a, 12b is provided so that the die-cutting at the time of shaping | molding can be performed easily, and about 1-3 degrees may be sufficient normally. A resin gear 13 is provided with a pin insertion hole 14 for inserting the gear pin 12. The pin insertion hole 14 is also formed with two-step tapered portions 14a and 14b corresponding to the two-step tapered portions 12a and 12b of the gear pin 12. Here, the minimum outer diameter of the tapered portion 12a on the larger diameter side of the gear pin 12 is set to be larger than the minimum inner diameter of the pin insertion hole 14 even if there is a manufacturing error.
[0011]
In the gear device having the above configuration, as shown in FIG. 1B, the gear 13 and the tapered portion 14 a on the large diameter side of the pin insertion hole 14 are changed to the tapered portion 12 a on the large diameter side of the gear pin 12 as shown in FIG. It is attached so that it may be fitted, so that the gear 13 can be stably and rotatably held by the gear pin 12. By the way, when an operator attaches the gear 13 to the gear pin 12, the attaching direction of the gear 13 may be reversed by mistake. In this case, as shown in FIG. 1 (c), the gear insertion hole 14 is inserted into the gear pin 12 through the portion with the smallest inner diameter, so that the portion with the smallest inner diameter hits the step 12c of the gear pin 12 and beyond. Therefore, the gear 13 is not inserted to the gear pin 12 to the root. Thereby, the operator can immediately know that the gear 13 is not correctly inserted, and can correct the mounting direction correctly. Thus, the gear 13 is always attached in the correct direction with respect to the gear pin 12, and the gear 12 rotates smoothly during use and does not cause troubles such as locking.
[0012]
In the above embodiment, the pin 12 and the pin insertion hole 14 are formed with two stages of taper portions, but it goes without saying that the taper portions may have three or more stages.
[0013]
【The invention's effect】
As is clear from the above description, the present invention is formed of a resin, a gear pin formed by combining a plurality of taper portions having different diameters and having a diameter that decreases toward the tip, and inserted into the gear pin. A gear having a pin insertion hole having a plurality of taper portions corresponding to the taper portion of the gear pin made of resin, and the gear pin has a minimum outer diameter larger than a minimum inner diameter of the pin insertion hole. When the gear is attached to the gear pin, the insertion direction is reversed because the gear stops in the middle of the gear pin and is not inserted to the root. For this reason, it is possible to prevent reverse gear insertion and avoid a situation where the gear locks during use, and the resin gear pin and gear can be used stably. It can have an effect that costs can be reduced.
[0014]
Here, if the gear pin is formed integrally with a recording device chassis formed by resin molding, there is no need to attach the gear pin to the chassis, and the cost can be further reduced. It is done.
[Brief description of the drawings]
FIG. 1A is a schematic sectional view showing a gear device according to an embodiment of the present invention in a state before assembling; FIG. 1B is a schematic sectional view showing the gear device in a state where a gear is correctly attached to a gear pin; ) Is a schematic cross-sectional view showing the gear device in a state where the gear is reversely inserted into the gear pin. FIG. 2A is a schematic cross-sectional view showing a state where the gear is correctly assembled to the resin gear pin. b) Schematic sectional view showing the state when the gear is inserted in reverse on the gear pin.
11 Chassis 12 Gear pins 12a, 12b Tapered portion 12c Stepped portion 13 Gear 14 Pin insertion holes 14a, 14b Tapered portion

Claims (2)

Corresponding to a gear pin formed of resin and formed by combining a plurality of taper portions having different diameters so that the diameter becomes smaller toward the tip, and the taper portion of the gear pin inserted into the gear pin and formed of resin. A gear device provided with a pin insertion hole having a plurality of taper portions, wherein the gear pin includes a taper portion having a minimum outer diameter larger than a minimum inner diameter of the pin insertion hole. .   2. The gear device according to claim 1, wherein the gear pin is integrally formed with a chassis for a recording device formed by resin molding.

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