JP4543969B2 - Gear mounting structure - Google Patents

Description

  The present invention relates to a gear mounting structure used for a drive transmission mechanism of equipment such as a copying machine, a printer, and a facsimile machine.

  In devices such as copiers, printers, and facsimile machines, the driving force from a driving device such as a motor is transmitted to each part by a transmission mechanism including mechanical elements such as gears and clutches. In such a transmission mechanism, many gears are used to perform a drive transmission operation and a deceleration operation. However, as the number of gears increases, the number of parts for the installation increases and the installation work time increases. Cost, which increases the cost.

Therefore, a snap fit is used in order to easily perform the gear mounting operation. For example, Patent Document 1 describes that in order to attach a drive gear to the rotation shaft of a pickup roller, a snap fit is formed by cutting a right end portion of the rotation shaft into four equal parts. As an example of using a snap fit for assembling a clutch, in Patent Document 2, based on a structure in which two annular bodies are integrated with each other by a snap fit, a rolling element of a rolling bearing and a sprag of a one-way clutch are used. A rolling bearing integrated one-way clutch provided with a cage for holding the roller is described.
JP 2003-104574 A JP 2000-304068 A

  In the above-described prior art, by using the snap fit, the increase in the number of parts can be suppressed and the mounting work can be facilitated, but there is a drawback that the strength of the snap fit portion is lowered when the gear is mounted on the rotating shaft. . In particular, when the gears mesh with each other, if a load is applied to the gears, the snap-fit portion is bent inward and the meshing between the gears is out of order, so that the driving force cannot be transmitted smoothly. When such a failure of the transmission mechanism occurs, in a device that requires high-precision operation such as a copying machine or a printer, it causes a malfunction.

  Accordingly, an object of the present invention is to provide a gear mounting structure that can be easily mounted without reducing the strength of the snap fit portion when the gear is mounted using the snap fit.

A gear mounting structure according to the present invention includes a cylindrical gear shaft having a snap-fit portion formed by cutting in an axial direction from a tip portion, and is inserted from the tip portion of the gear shaft and engages with the snap-fit portion. a gear member which is held in the gear axis ensures that components operate Do and at least a reinforcing member on which the snap-fit portion is inserted in the inner peripheral surface of the forming portion of the gear shaft, the reinforcing member includes a cylindrical It characterized that you have the snap-fit portion cuts in the axial direction to engage a notch to form the snap-fit portion of the gear shaft is formed from an end portion opposite to the tip end portion of the gear shaft is formed in a And

  With the above configuration, the reinforcing member is inserted into the inner peripheral surface of the cylindrical gear shaft, so that the reinforcing member abuts on the inner surface side of the snap fit portion and the snap fit portion bends to the inner surface side. Can be prevented. In other words, when the gear member is inserted into the gear shaft, the snap fit portion is bent so that the gear member can be easily attached, and after the gear member is attached, the reinforcing member is brought into contact with the inner surface of the snap fit portion. If inserted, even if a load is applied to the gear member, the snap fit portion does not bend and it is possible to prevent the gear member from being defective.

  Also, if the reinforcing member is formed in a cylindrical shape and cut into the axial direction from the end opposite to the tip of the gear shaft to form a snap fit portion, the reinforcing member is inserted into the inner peripheral surface of the gear shaft. By wearing, the snap-fit portion of the reinforcing member engages with the inner peripheral surface of the gear shaft to prevent the reinforcing member from coming off. Therefore, the reinforcing member can be easily attached, and the attaching operation can be made efficient. If the snap-fit part of the reinforcing member is set to engage with the notch of the snap-fit part of the gear shaft, the notch of the snap-fit part can also be used as a retaining member for the reinforcing member, simplifying the mounting structure It becomes possible to do.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is an exploded perspective view of an embodiment according to the present invention. The gear mounting structure includes a gear shaft 2 projecting laterally from the main body frame 1, a gear member 3 attached to the gear shaft 2, and a reinforcing member 4 inserted into the gear shaft 2. The gear shaft 2 is formed in a cylindrical shape, and a tip portion of the gear shaft 2 is formed with a small thickness and a mounting portion 20 to which the gear member 3 is mounted. From the mounting portion 20 to the root portion, the gear shaft 2 is formed. It is formed in the base 21 having a large thickness. The gear member 3 is provided with a gear portion 30 (a gear is omitted in FIG. 1) with a disc-shaped peripheral edge portion formed in a predetermined thickness, and is inserted into the gear shaft 2 at the center thereof. A mounting hole 31 is formed.

  2 is a cross-sectional view taken along line AA (FIG. 2A) perpendicular to the axial direction of the gear shaft 2 in the mounting portion 20, and a cross-sectional view taken along line BB perpendicular to the axial direction of the gear shaft 2 in the base portion 21. (B)) is shown. As shown in FIGS. 1 and 2, a pair of cuts 22 a and 22 b are formed from the tip of the mounting portion along the axial direction of the gear shaft 2 over the top of the mounting portion 20 and the base portion 21. A narrow snap fit portion 23 is formed by the cuts 22a and 22b, and the thickness of the snap fit portion 23 is the same as that of the mounting portion 20 from the base portion 21 to the mounting portion 20, and the tip thereof. An engaging portion 24 having a predetermined width is formed in the portion. The engaging portion 24 has an inclined surface 24a that is inclined upward as it goes from the tip to the root portion.

  FIG. 3 shows a view of the gear shaft 2 as viewed from above in the CC cross section. The snap fit portion 23 is formed thinly by the cuts 22a and 22b that are deeply cut from the tip of the mounting portion 20 to the root portion, and is thinned, so that it can be easily bent in the vertical direction. Therefore, when the attachment hole 31 of the gear member 3 is inserted into the tip of the gear shaft 2, the inclined surface 24a of the engagement portion 24 comes into contact with the attachment hole 31 and can be easily pushed down. What is necessary is just to set suitably the width | variety and length of the snap fit part 23 so that it may have flexibility.

  FIG. 4 shows a cross-sectional view of the state in which the gear member 3 is mounted on the gear shaft 2, cut in the vertical direction along the central axis of the gear shaft 2. In the gear member 3, when the mounting hole 31 is inserted from the tip of the gear shaft 2, the engaging portion 24 is pushed down, and the mounting hole 31 is disengaged from the inclined surface 24 a of the engaging portion 24. Then, the snap fit portion 23 that has been bent returns to the upper side, and the state shown in FIG. 4 is obtained. The width between the engaging portion 24 and the base portion 21 is set to be substantially the same as or slightly wider than the thickness of the mounting hole portion 31 of the gear member 3, and the outer diameter of the mounting portion 20 is substantially the same as the inner diameter of the mounting hole portion 31. Therefore, the mounted gear member 3 is rotatable about the central axis of the gear shaft 2 between the engaging portion 24 and the base portion 21 and does not move in the axial direction of the central shaft and does not come off. Is mounted as follows.

  In the state of FIG. 4, since the load is not applied to the gear member 3, the gear member 3 is set to rotate about the central axis of the gear shaft 2. When a load is applied, the strength of the snap fit portion 23 is weak, so that it bends downward and the gear member 3 cannot rotate around the central axis of the gear shaft 2. Therefore, it is necessary to limit the load applied to the gear member 3, and the degree of freedom is reduced in designing the drive transmission mechanism.

  Therefore, in the present invention, the strength reduction due to the snap fit portion 23 is prevented by inserting the reinforcing member 4 that reinforces the strength of the snap fit portion 23 into the gear shaft 2. FIG. 5 shows a cross-sectional view of a range of 120 degrees cut along the central axis of the gear shaft 2 in a state where the gear member 3 is mounted on the gear shaft 2. The reinforcing member 4 is formed in a cylindrical shape, and its outer diameter is set to be substantially the same as the inner diameter of the gear shaft 2. A contact portion 25 is formed on the inner surface of the mounting portion 20 of the gear shaft 2 so as to cross the lower portion of the tip opening, and the reinforcing member 4 is inserted into the gear shaft 2 to be inserted into the front end portion (gear shaft). 2 until the abutting portion 25 abuts against the abutting portion 25.

  FIG. 6 shows a top view of the reinforcing member 4 shown in FIG. 5 as viewed from above. A notch 40 having a predetermined width is formed along the axial direction from the rear end at the rear end of the reinforcing member 4 (the end opposite to the tip of the gear shaft 2). Further, incisions 41a and 41b are formed in the axial direction. And the snap fit part 42 is formed in the narrow shape by the notches 41a and 41b, and the engaging part 43 is formed in the front-end | tip part (rear end side of the reinforcement member 4) of the snap fit part 42. FIG. The engaging portion 43 is formed with an inclined surface 43 a that is inclined upward as it goes from the front end to the rear end of the reinforcing member 4. What is necessary is just to set the width | variety and length of the snap fit part 42 so that it may have flexibility. The width of the engaging portion 43 is formed to be substantially the same as or smaller than the width of the notch 22a or 22b so that it can be fitted into the notch 22a or 22b formed in the gear shaft 2 as will be described later.

  FIG. 7 is a cross-sectional view similar to FIG. 5 showing a state where the reinforcing member 4 is inserted into the gear shaft 2. When the reinforcing member 4 is inserted into the gear shaft 2, the inclined surface 43 a of the engaging portion 43 of the snap fit portion 42 comes into contact with the inner surface of the gear shaft 2, and the snap fit portion 42 bends downward. . When the reinforcing member 4 is further inserted in this state, the engaging portion 43 is inserted while remaining in contact with the inner surface of the gear shaft 2, and when the engaging portion 43 reaches the notch 22b, the engaging portion 43 is inserted. Is fitted into the notch 22b. Then, the rear end surface of the engaging portion 43 comes into contact with the surface of the base portion of the cut 22b, and the reinforcing member 4 cannot move in the direction opposite to the insertion direction, and is prevented from coming off. In this state, the front end side of the reinforcing member 4 is in contact with the contact portion 25 and the rear end side is in contact with the surface of the root portion of the cut 22b at the engaging portion 43, so that the reinforcing member 4 does not move in the axial direction. It is held in the shaft 2. The front end portion of the reinforcing member 4 is in contact with the lower surface of the snap fit portion 23 of the gear shaft 2, and the snap fit portion 23 bends downward in order to reinforce the snap fit portion 23 from below. Therefore, even if a load is applied to the gear member 3, the drive transmission of the gear member 3 is not affected. Further, the reinforcing member 4 can be easily pulled out from the gear shaft 2 by pushing the engaging portion 43 of the snap-fit portion 42 downward and releasing the engagement with the notch 22b with the reinforcing member 4 inserted. The pulled-out reinforcing member 4 can be reused and has a mounting structure in which parts can be recycled.

  In FIG. 7, the engaging portion 43 of the reinforcing member 4 is fitted in the cut 22b, but may be fitted in the cut 22a. When inserting the reinforcing member 4, the reinforcing member 4 is inserted until the reinforcing member 4 abuts against the abutting portion 25, and then the reinforcing member 4 is appropriately rotated so that the engaging portion 43 is fitted with either of the notches 22 a or 22 b. It becomes like this.

  In the example described above, the snap fit portion 42 is formed to prevent the reinforcing member 4 from coming off. However, when the recycling of the reinforcing member 4 is not considered, the reinforcing member 4 is simply formed in a cylindrical shape or a columnar shape. Then, it may be inserted into the lower surface of the snap fit portion 23 and fixed with an adhesive. Moreover, the snap fit part formed in the gear shaft 2 may be formed in plural, and is not particularly limited.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a gear mounting structure used in a drive transmission mechanism of precision equipment such as a copying machine, a printer, and a facsimile machine, and in particular, in a gear train that transmits and transmits a developing roller and a photosensitive drum of a copying machine. However, by using the gear mounting structure of the present invention, a gear train having high accuracy, durability and easy mounting can be obtained.

It is a disassembled perspective view regarding embodiment which concerns on this invention. They are AA sectional drawing (FIG. 2 (a)) and BB sectional drawing (FIG.2 (b)) perpendicular | vertical to the axial direction of a gear shaft. It is the figure which looked at the gear shaft 2 from upper direction in CC cross section. It is sectional drawing cut | disconnected in the perpendicular direction along the central axis of a gear shaft. It is sectional drawing which cut out the range of 120 degree | times along the central axis of a gear shaft. It is the top view which looked at the reinforcement member from the upper part. It is sectional drawing which cut out the range of 120 degree | times along the central axis of a gear shaft in the state which inserted the reinforcement member.

Explanation of symbols

1 Body frame 2 Gear shaft
23 Snap fit part
24 Engagement part 3 Gear member
31 Mounting hole 4 Reinforcing member
42 Snap fit part
43 Engagement part

Claims (1)

A cylindrical gear shaft having a snap-fit portion formed by cutting in the axial direction from the tip portion, and being held by the gear shaft by being inserted from the tip portion of the gear shaft and engaging with the snap-fit portion. a gear member, Ri Do and at least a reinforcing member on which the snap-fit portion is inserted in the inner peripheral surface of the forming portion of the gear shaft, the reinforcing member of the gear shaft is formed in a cylindrical shape gear attachment structure characterized that you have snap-fit portion that engages the notch to form the snap-fit portion of the gear shaft cuts in the axial direction is formed from the end opposite to the tip.

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