JP2009270594A - Bearing device and image forming device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for keeping the rotation and sliding motion of a shaft smooth while effectively radiating friction heat between the shaft and the bearing device, and to provide an image forming device equipped therewith. <P>SOLUTION: The bearing device 5 for supporting the shaft 4a includes a bearing part 50 fitted to a bearing mounting hole 1a of a body frame 1, and a mounted part 51 mounted on the body frame 1. The bearing part 50 has a bearing hole 5b for supporting the shaft 4a, and at least three outer periphery ribs 5a provided on the outer periphery of the bearing hole 5b and protruded in the radial direction of the shaft 4a. The front ends of the outer periphery ribs 5a contact the inner periphery of the bearing mounting hole 1a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bearing device that supports a rotating shaft of a gear member that drives an apparatus main body and a sliding shaft, and an image forming apparatus such as a copying machine, a facsimile, a printer, and a multi-function machine including the same.

  2. Description of the Related Art Conventionally, a bearing device (Patent Document 1) that is fastened and held by forming a mounting hole in a support member and fitting into the mounting hole is known, and an image forming apparatus including the same is known.

  FIG. 8 shows a schematic configuration of a conventional bearing device. The bearing device 100 according to the conventional example includes an outer cylinder part 100a that is fitted into a mounting hole formed in the support member 110 and is held tightly, and an inner cylinder part 100b having a bearing hole. The cylindrical part 100b is connected by the rib part 100c.

Thus, by connecting the inner cylinder part 100b and the outer cylinder part 100a with the rib part 100c, a gap 120 is formed between the inner cylinder part 100b and the outer cylinder part 100a, and the friction generated between the bearing hole and the shaft. Heat can be radiated from the gap 120 to the outside.
JP-A-8-284959

  However, the bearing device according to the conventional example and the image forming apparatus including the same cause the following problems.

  In recent years, image forming apparatuses are required to have high image quality and high speed, and in order to achieve this purpose, there is a demand for a structure that keeps the gears rotating at high speed and stably without causing uneven rotation. ing.

  In other words, when the gear is rotated at a high speed, the frictional heat generated between the bearing hole and the shaft increases, so the problem is how to efficiently dissipate this frictional heat and suppress the shape change of the bearing device due to thermal expansion. It is mentioned as one.

  However, in the bearing device according to the conventional example, although the frictional heat generated between the bearing hole and the shaft can be radiated from the gap between the inner cylindrical portion and the outer cylindrical portion, the frictional heat is generated when the shaft rotates at high speed. The frictional heat cannot be released from the air gap.

  As a result, frictional heat is transmitted from the rib part to the outer cylinder part, and a difference in temperature and expansion occurs between the outer cylinder part and the support member, so that the shape of the inner cylinder part changes and shaft rotation unevenness may occur. There is. Moreover, there is a possibility that the torque increase and the component life may be affected.

  In addition, when the linear expansion coefficient differs between the shaft and the bearing device, even if the shaft and the bearing device are molded with high accuracy, the shaft diameter is larger than the diameter of the bearing hole due to frictional heat as the gear rotates. Can be bigger. As a result, the movement of the shaft is deteriorated, and there is a risk of causing uneven rotation of the shaft.

  Further, the frictional heat generated between the shaft and the bearing device may cause the bearing device and the shaft to melt, and the shaft may adhere to the bearing device.

  The present invention has been made in view of the above circumstances, and includes a bearing device that can effectively dissipate frictional heat between the shaft and the bearing device, and can keep the shaft rotating and sliding smoothly. An object is to provide an image forming apparatus.

In order to achieve the above object, the present invention provides:
A bearing portion that fits into a bearing mounting hole formed in the bearing mounting member;
An attachment portion attached to the bearing attachment member;
With
In the bearing device that supports the shaft,
In the bearing portion,
A bearing hole for supporting the shaft;
At least three outer peripheral ribs provided on the outer periphery of the bearing hole and projecting in the radial direction of the shaft;
Is provided,
The tip of the outer peripheral rib is
It is in contact with the inner periphery of the bearing mounting hole.

Also,
A bearing portion that fits into a bearing mounting hole formed in the bearing mounting member;
A mounting portion attached to the bearing mounting member;
With
In the bearing device that supports the shaft,
In the bearing portion,
A bearing inner cylinder that supports the shaft;
A bearing outer cylinder provided on the outer periphery of the bearing inner cylinder; and
At least three ribs connecting the bearing inner cylinder part and the bearing outer cylinder part;
At least three outer peripheral ribs provided on an outer periphery of the bearing outer cylinder portion and projecting in a radial direction of the shaft;
Is provided,
The tip of the outer peripheral rib is
Contacting the inner periphery of the bearing mounting hole,
The rib and the outer peripheral rib are provided so that their phases are different from each other.

  As described above, according to the present invention, the bearing device capable of effectively radiating the frictional heat between the shaft and the bearing device, keeping the shaft rotating or sliding smoothly, and extending the service life. And an image forming apparatus including the same can be provided.

  The best mode for carrying out the present invention will be exemplarily described in detail below based on the embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

[First Embodiment]
With reference to FIGS. 1-4, the bearing apparatus which concerns on the 1st Embodiment of this invention, and an image forming apparatus provided with the same are demonstrated.

  FIG. 1 is a schematic configuration diagram of a bearing device 5 according to the present embodiment. As shown in FIG. 1, the bearing device 5 according to the present embodiment includes a bearing portion 50 that supports a shaft, and an attachment portion 51 in which the bearing portion 50 is formed. A bearing hole 5b for supporting the shaft of the main body gear is formed in the bearing portion 50, and six outer peripheral ribs 5a protruding in the radial direction of the shaft are formed on the outer periphery of the bearing hole 5b. Further, the virtual circle formed by connecting the tips of the outer peripheral ribs 5a and the bearing hole 5b are formed concentrically.

  Further, the mounting portion 51 of the bearing device 5 is fitted into a holding portion 5c for mounting the bearing device 5 to the main body frame (bearing mounting member) 1 and a hole formed in the main body frame. A boss 5e for preventing rotation with the shaft is formed. In addition, the bearing device 5 having such a configuration is integrally formed of synthetic resin. Thereby, the bearing device 5 can be manufactured without increasing the number of parts.

  FIG. 2 shows a front view when the bearing device 5 according to the present embodiment is attached to the main body frame 1 of the image forming apparatus. As shown in FIG. 2, the main body frame 1 is formed with a hole portion into which the holding portion 5c and the boss 5e are fitted. Thereby, the bearing device 5 can be reliably attached to the main body frame 1.

  A bearing mounting hole 1a is formed in the main body frame 1, and the bearing portion 50 of the bearing device 5 is provided with a bearing so that the tip of the outer peripheral rib 5a of the bearing device 5 is in contact with the inner periphery of the bearing mounting hole 1a. It fits into the mounting hole 1a.

  Thereby, a plurality of gaps 7 partitioned by the outer peripheral rib 5a are formed between the bearing device 5 and the bearing mounting hole 1a. The bearing mounting hole 1a and the bearing hole 5b are positioned by the outer peripheral rib 5a so as to be concentric.

  3 and 4 are schematic configuration diagrams when the bearing device 5 is mounted on the image forming apparatus. FIG. 3 shows a schematic configuration when the bearing device 5 is mounted on the drive transmission portion of the laser beam printer, and FIG. 4 shows an exploded view of the bearing device 5 and the image forming apparatus.

  The image forming apparatus is provided with a body gear 4 to which a driving force is transmitted from a drive motor 3 as a drive source. The body gear 4 includes a shaft 4a on the body frame 1 side and a shaft 4b on the sheet metal side plate 2 side. , Is formed. The shaft 4 b on the sheet metal side plate 2 side is engaged with a hole formed in the sheet metal side plate 2. The sheet metal side plate 2 is positioned and fixed to the main body frame 1 with screws or the like.

  A bearing device 6 is provided on the shaft 4 a of the main body gear 4, and the bearing device 5 according to the present embodiment is provided on the shaft 4 b of the main body gear 4. However, the bearing device 6 may have the same configuration as the bearing device 5 according to the present embodiment.

  According to the above configuration, the frictional heat generated between the shaft 4 a of the main body gear 4 and the bearing device 5 is effective from the gap 7 between the outer peripheral rib 5 a and the bearing mounting hole 1 a formed in the main body frame 1. Heat can be released.

  Thereby, the temperature rise of the bearing apparatus 5 can be reduced, and it becomes possible to suppress the shape change accompanying a temperature rise. As a result, it is possible to provide an image forming apparatus that can maintain smooth rotation without causing uneven rotation of the main body gear 4 and achieve high image quality and high speed. Further, it is possible to prevent the main body gear 4 and the bearing device 5 from being melted and fixed due to frictional heat.

Furthermore, the bearing device 5 is tightened by the temperature difference and the expansion difference between the bearing mounting hole 1a formed in the main body frame 1, and the shape change of the bearing device 5 can be suppressed.

  In the present embodiment, six outer peripheral ribs 5a are provided. However, the number of outer peripheral ribs 5a is not limited to this and may be at least three. If there are three or more outer peripheral ribs 5 a, the bearing hole 5 b of the bearing device 5 can be positioned with respect to the bearing mounting hole 1 a of the main body frame 1.

  That is, the bearing device 5 according to the present embodiment is configured such that the tips of the outer peripheral ribs 5a are in contact with the bearing mounting holes 1a of the main body frame 1, so that frictional heat is hardly transmitted to the main body frame 1 side, and the shape of the bearing device 5 is reduced. It becomes possible to suppress changes and the like.

  Further, the image forming apparatus including the bearing device 5 can also effectively dissipate frictional heat without causing a change in shape even when the main body gear 4 rotates at high speed. Can be achieved.

  Further, by using the bearing device 5 according to the present embodiment for a drive gear train that drives an image forming means (photosensitive drum) that forms an image on a sheet material, each gear can be smoothly rotated. , Image defects due to rotation unevenness can be reduced. Further, by using this bearing device 5 for the sliding portion of the image forming apparatus, it is possible to provide an image forming apparatus in which an increase in torque is suppressed.

  As described above, the present embodiment provides a bearing device that can effectively dissipate frictional heat between the shaft and the bearing device and can keep the shaft rotating and sliding smoothly, and an image forming apparatus including the bearing device. It becomes possible to do.

[Second Embodiment]
With reference to FIG. 5, a bearing device 5 according to a second embodiment of the present invention and an image forming apparatus including the same will be described. FIG. 5 is a front view when the bearing device 5 according to the present embodiment is attached to the main body frame 1.

  As shown in FIG. 5, the bearing device 5 according to the present embodiment is different from the first embodiment in the shape of the outer peripheral rib 5a. Since other configurations are the same as those in the first embodiment, description thereof will be omitted, and only the configuration of the outer peripheral rib 5a will be described here.

  In the present embodiment, six outer peripheral ribs 5a are formed on the outer periphery of the bearing hole 5b, and the virtual circle formed by connecting the tips of the outer peripheral ribs 5a and the bearing hole 5b are formed concentrically. Further, the outer peripheral rib 5a has a shape having elasticity in the radial direction of the shaft.

  According to this configuration, even when the shaft of the body gear 4 vibrates, the bearing device 5 can follow the shaft, so that the rotation (or sliding) of the body gear 4 can be kept smooth. Further, deformation of the bearing device 5 due to thermal expansion can be absorbed by elastic deformation of the outer peripheral rib 5a.

  Further, as in the first embodiment, since the gap 7 is formed between the outer peripheral rib 5a and the bearing mounting hole 1a, the frictional heat generated between the shaft and the bearing device 5 is effectively used. Can dissipate heat.

In addition, by using the bearing device 5 according to the present embodiment for a drive gear train that drives an image forming unit (photosensitive drum or the like) that forms an image on a sheet material, each gear can be rotated smoothly. Image defects due to rotation unevenness can be reduced. Further, by using this bearing device 5 for the sliding portion of the image forming apparatus, it is possible to provide an image forming apparatus in which an increase in torque is suppressed.

  That is, according to the present embodiment, since the outer peripheral rib 5a has elasticity in the radial direction, even if the difference in linear expansion coefficient between the bearing device 5 and the main body frame 1 is large, the shape change of the bearing device 5 due to thermal expansion is caused. It can be absorbed by elastic deformation of the outer peripheral rib 5a.

  As a result, it is possible to provide a bearing device that can effectively dissipate frictional heat between the shaft and the bearing device and keep the shaft rotating and sliding smoothly, and an image forming apparatus including the bearing device. .

[Third Embodiment]
With reference to FIGS. 6 and 7, a bearing device 5 according to a third embodiment of the present invention and an image forming apparatus including the same will be described. FIG. 6 is a front view when the bearing device 5 according to the present embodiment is attached to the main body frame 1. FIG. 7 is a schematic configuration diagram when the bearing device 5 according to the present embodiment is viewed from the side.

  In the bearing device 5 according to the present embodiment, a bearing inner cylinder portion 5g that supports the shaft of the main body gear 4 and a bearing outer cylinder portion 5f formed on the outer peripheral side thereof are formed, and the bearing inner cylinder portion 5g is formed. And the bearing outer cylinder part 5f are connected by a rib 5h, and an outer peripheral rib 5a is provided on the outer periphery of the bearing outer cylinder part 5f. Further, the phases of the rib 5h and the outer peripheral rib 5a are made different from each other. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  According to this configuration, the gap 8 is formed between the bearing inner cylinder part 5g and the bearing outer cylinder part 5f, and further, the gap 7 is formed between the main body frame 1 and the bearing outer cylinder part 5f. Therefore, the frictional heat generated between the shaft and the bearing inner cylinder portion 5g can be radiated through the gap 8 and the gap 7, and the frictional heat can be radiated more effectively.

  Moreover, the stress which generate | occur | produces in the bearing apparatus 5 accompanying a thermal expansion can be disperse | distributed by making the phase of the rib 5h and the outer periphery rib 5a mutually differ. Therefore, it becomes possible to suppress the shape change of the bearing device 5 due to thermal expansion.

  Note that the gap 8 may have a hole shape as long as it has a shape that dissipates frictional heat. Further, the number of ribs 5h and outer peripheral ribs 5a is not limited to the number shown in FIG. Further, the outer peripheral rib 5a in the present embodiment may have a shape having elasticity as in the second embodiment.

  In addition, by using the bearing device 5 according to the present embodiment for a drive gear train that drives an image forming unit (photosensitive drum or the like) that forms an image on a sheet material, each gear can be rotated smoothly. Image defects due to rotation unevenness can be reduced. Further, by using this bearing device 5 for the sliding portion of the image forming apparatus, it is possible to provide an image forming apparatus in which an increase in torque is suppressed.

  As described above, the present embodiment provides a bearing device that can effectively dissipate frictional heat between the shaft and the bearing device and can keep the shaft rotating and sliding smoothly, and an image forming apparatus including the bearing device. It becomes possible to do.

Schematic configuration diagram of a bearing device according to the first embodiment The front view at the time of attaching the bearing apparatus which concerns on 1st Embodiment to a main body frame Schematic configuration diagram when the bearing device according to the first embodiment is attached to an image forming apparatus 1 is an exploded view of a bearing device and an image forming apparatus according to a first embodiment. The front view at the time of attaching the bearing apparatus which concerns on 2nd Embodiment to a main body frame The front view at the time of attaching the bearing apparatus which concerns on 3rd Embodiment to a main body frame The schematic block diagram at the time of attaching the bearing device which concerns on 3rd Embodiment to a main body frame Schematic configuration diagram of a conventional bearing device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body frame 1a Bearing mounting hole 4 Body gear 5 Bearing device 5a Outer peripheral rib 5b Bearing hole 5c Holding part 5e Boss 5g Bearing inner cylinder part 5f Bearing outer cylinder part 5h rib 7 Gap 8 Gap

Claims (5)

A bearing portion that fits into a bearing mounting hole formed in the bearing mounting member;
An attachment portion attached to the bearing attachment member;
With
In the bearing device that supports the shaft,
In the bearing portion,
A bearing hole for supporting the shaft;
At least three outer peripheral ribs provided on the outer periphery of the bearing hole and projecting in the radial direction of the shaft;
Is provided,
The tip of the outer peripheral rib is
A bearing device that is in contact with an inner periphery of the bearing mounting hole. A bearing portion that fits into a bearing mounting hole formed in the bearing mounting member;
A mounting portion attached to the bearing mounting member;
With
In the bearing device that supports the shaft,
In the bearing portion,
A bearing inner cylinder that supports the shaft;
A bearing outer cylinder provided on the outer periphery of the bearing inner cylinder; and
At least three ribs connecting the bearing inner cylinder part and the bearing outer cylinder part;
At least three outer peripheral ribs provided on an outer periphery of the bearing outer cylinder portion and projecting in a radial direction of the shaft;
Is provided,
The tip of the outer peripheral rib is
Contacting the inner periphery of the bearing mounting hole,
The said rib and the said outer periphery rib are provided so that a mutual phase may differ, The bearing apparatus characterized by the above-mentioned. The outer peripheral rib is
The bearing device according to claim 1, wherein the bearing device has a shape having elasticity in a radial direction of the shaft. The device body is
The bearing device according to any one of claims 1 to 3, wherein the bearing device is integrally formed of a synthetic resin. A bearing device according to any one of claims 1 to 4,
Image forming means for forming an image on a sheet material,
An image forming apparatus, wherein the bearing device is attached to a shaft of a driving gear for transmitting a driving force to the image forming means.

Images