JP2018204644A - Bearing and image formation device - Google Patents

Abstract

To provide a bearing having high accuracy and durability, and including stable seal performance.SOLUTION: A bearing 1 comprises a metal outer race 2, a metal inner race 3, a plurality of balls 4 arranged in a gap between the inner race and the outer race, wherein rolling the balls 4 makes one of the inner race 3 and outer race 2 relatively move to the other one. In at least one of the inner race 3 and outer race 2, guide walls 23, 24, 33, 34 made of elastomer are provided, wherein a projection is formed around slide parts 22, 32 between the ball 4 and the inner race 3 or outer race 2, to determine a position of the ball 4 with respect to the inner race 3 or outer race 2. The guide walls 23, 24, 33, 34 comprise seal parts 25, 35 extending to the other one of the inner race 3 and outer race 2 and configured to seal the interval.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bearing and an image forming apparatus such as an electrophotographic copying machine and an electrophotographic printer provided with the bearing.

  In an electrophotographic image forming apparatus, fine powder toner is used as a developer. This toner is stirred by a stirring member in order to suppress aggregation and is transported by a transport member. For this reason, when a bearing is used for the shaft support portion of the rotating shaft of the agitating member or the conveying member, toner exists in the vicinity of the bearing.

  Here, in the bearing, the gap between the outer race (outer ring) and the inner race (inner ring) where rolling elements such as balls are arranged is set as small as possible to avoid rattling. Therefore, if foreign matter such as toner enters the gap, rolling of the rolling element is hindered and smooth rotation of the bearing may be hindered, or the durable life of the bearing may be shortened by damaging these members. There is.

  Therefore, a configuration is known in which a seal member that covers the gap is attached in order to prevent foreign matter from entering the gap. The seal member is generally composed of a ring-shaped thin sheet metal, and the outer diameter portion is fitted into and supported by a groove formed in the outer race.

  Patent Document 1 proposes a bearing in which a seal member formed of elastic plastic is integrated with an outer race and an inner race, and the seal member rotates while abutting against a side surface of the opposite outer race or inner race. (FIG. 6B).

JP 2006-329286 A

  The manufacturing process of the bearing described in Patent Document 1 is considered as follows. That is, as shown in FIG. 5A, first, the outer race 102 and the inner race 103 in which the seal portions 125 and 135 are integrated are formed.

  Next, as shown in FIG. 5B, inside the inner diameter of the outer race 102, the inner race 103 is moved toward one side, and a plurality of balls 104 are inserted into the other side where the gap is increased.

  Next, as shown in FIG. 6A, the ball 104 is moved in the circumferential direction, and the retainer 105 is inserted when the diameter centers of the inner race 103 and the outer race 102 substantially coincide with each other. Fix it at regular intervals in the direction. Thereby, as shown in FIG.6 (b), the bearing 101 of patent document 1 is completed.

  Here, as shown in FIGS. 5B and 6A, when the ball 104 is inserted or when the retainer 105 is inserted, the seal portion 125 of the outer race 102 and the seal portion 135 of the inner race 103 are bent. At this time, if the bending becomes uneven, for example, the base end portions 128 and 138 of the seal portions 125 and 135 may be partly stressed and may be plastically deformed beyond the elastic region. . In this case, the contact pressure with respect to the contact surface of the seal part 125 and the contact pressure with respect to the contact surface of the seal part 135 and the contact state are not uniform, the sealing performance becomes insufficient, and foreign matter enters the gap. There is a risk of intrusion.

  Since the outer race 102 and the inner race 103 are made of plastic, they are easily worn during durable rotation, and the processing accuracy is lower than that of metal. For this reason, there is a concern that the play with the ball 104 becomes large and the rotation accuracy is lowered.

  Therefore, the present invention has been made in view of such a current situation, and an object thereof is to provide a bearing having high accuracy and high durability and having a stable sealing performance.

  A typical configuration of a bearing according to the present invention for achieving the above object is that a plurality of rolling elements are arranged in a gap between a metal inner ring and a metal outer ring, and the rolling elements roll. In the bearing in which one of the inner ring and the outer ring moves relative to the other, at least one of the inner ring and the outer ring is provided, and a sliding portion between the rolling element and the inner ring or the outer ring is provided. A guide member formed of an elastomer that forms a convex portion around and determines a position of the rolling element with respect to the inner ring or the outer ring, and extends to one of the inner ring and the outer ring to seal the gap. It has a guide member provided with the seal part to do.

  According to the present invention, in a bearing, high accuracy and high durability can be achieved, and stable sealing performance can be provided.

1 is a schematic cross-sectional view of an image forming apparatus. It is the front view and sectional drawing of a bearing. It is a schematic cross section for demonstrating the manufacturing process of a bearing. It is a schematic cross section for demonstrating the manufacturing process of a bearing. It is a schematic cross section for demonstrating the manufacturing process of the conventional bearing. It is a schematic cross section for demonstrating the manufacturing process of the conventional bearing.

(First embodiment)
<Image forming apparatus>
Hereinafter, the overall configuration of the image forming apparatus A including the bearing according to the first embodiment of the present invention will be described with reference to the drawings together with the operation during image formation. Note that the dimensions, materials, shapes, relative arrangements, and the like of the described components are not intended to limit the scope of the present invention only to those unless otherwise specified.

  As shown in FIG. 1, the image forming apparatus A includes an image forming unit that forms an image by transferring a toner image onto a sheet that is a recording medium, a sheet feeding unit that supplies the sheet toward the image forming unit, A fixing unit for fixing the toner image on the sheet is provided.

  In forming an image, when a control unit (not shown) issues a print signal, the sheet S stacked and stored in the sheet stacking unit 60 is sent out to the image forming unit by the paper feed roller 59 and the transport roller 58.

  On the other hand, in the image forming unit, the surface of the photosensitive drum 51 (image carrier) is charged by applying a bias to the charging roller 52. Thereafter, the laser scanner unit 53 emits laser light from a light source (not shown), and irradiates the photosensitive drum 51 with the laser light according to image information. As a result, the potential of the photosensitive drum 51 is partially reduced, and an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 51.

  Thereafter, a bias is applied to the developing sleeve 56 provided in the developing device 54 (developing means), so that the toner is attached from the developing sleeve 56 to the electrostatic latent image formed on the surface of the photosensitive drum 51 to form a toner image. The

  The toner stored in the developing device 54 is agitated by rotating the agitating member 65 (rotating member) in the direction of arrow R in order to suppress aggregation. The rotating shaft 65a of the agitating member 65 is rotatably supported on the frame at both ends in the longitudinal direction via bearings 1 (see FIG. 2), and is rotated by a driving force transmitted from a motor (not shown). The configuration of the bearing 1 will be described later.

  Next, the toner image formed on the surface of the photosensitive drum 51 is sent to a transfer nip portion formed between the photosensitive drum 51 and the transfer roller 55. When the toner image arrives at the transfer nip portion, a bias having a polarity opposite to the toner charging polarity is applied to the transfer roller 55, and the toner image is transferred to the sheet S.

  Thereafter, the sheet S on which the toner image is transferred is sent to the fixing device 88, and the toner image is heated and pressurized by the fixing device 88 and fixed on the sheet S. Thereafter, the sheet S is conveyed by the discharge roller 62 and discharged to the discharge unit 63.

<Bearing>
Next, the bearing 1 will be described.

  2A is a front view of the bearing 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A. As shown in FIG. 2, the bearing 1 includes a metal annular outer race 2 (outer ring) and a metal annular inner race 3 (inner ring). A plurality of balls 4 (rolling elements), which are steel balls, are arranged in the gap between the outer race 2 and the inner race 3 in a state of being held at equal intervals in the circumferential direction by a metal retainer 5. .

  The outer race 2 is a guide member formed of an elastomer that forms a protrusion around the sliding portion 22 between the ball 4 and the outer race 2 to determine the position of the ball 4 in the thrust direction with respect to the outer race 2. The guide wall 23 and the guide wall 24 are provided. The guide wall 23 and the guide wall 24 are integrally formed on the inner peripheral surface of the outer race 2 and restrict movement of the ball 4 in the thrust direction.

  Further, the guide wall 24 extends toward the inner race 3, thereby forming a seal portion 25 that seals a gap between the outer race 2 and the inner race 3. The tip of the seal portion 25 is provided with a lip portion 26 that abuts with a predetermined contact pressure on a lip contact surface 37 (groove portion) whose surface is lowered circumferentially in the thrust direction on the side surface of the inner race 3. ing. The lip portion 26 is formed by press working.

  The inner race 3 is a guide member formed of an elastomer that forms a convex portion around the sliding portion 32 between the ball 4 and the inner race 3 to determine the position of the ball 4 in the thrust direction with respect to the inner race 3. The guide wall 33 and the guide wall 34 are provided. The guide wall 33 and the guide wall 34 are integrally formed on the outer peripheral surface of the inner race 3 and restrict the movement of the ball 4 in the thrust direction.

  Further, the guide wall 34 extends toward the outer race 2, thereby forming a seal portion 35 that seals a gap between the outer race 2 and the inner race 3. At the tip of the seal portion 35, a lip portion 36 that abuts with a predetermined contact pressure on a lip contact surface 27 (groove portion) whose surface is lowered in the circumferential direction on the side surface of the outer race 2 is provided. ing. The lip portion 36 is formed by press working.

  The ball 4 slides on the inner circumferential surface of the outer race 2 and the outer circumferential surface of the inner race 3 while being held by the retainer 5 along the guide walls 23 and 24 and the guide walls 33 and 34 in the circumferential direction. Roll to. As a result, one of the inner race 3 and the outer race 2 moves relative to the other (rotates).

  Further, when the inner race 3 and the outer race 2 move relative to each other, the lip portion 26 and the lip contact surface 37 and the lip portion 36 and the lip contact surface 27 rotate while sliding. Thereby, the sealing property of the clearance gap between the inner race 3 and the outer race 2 is maintained, and it is suppressed that a foreign material mixes in a clearance gap.

<Production method of bearing>
Next, a method for manufacturing the bearing 1 will be described.

  3 and 4 are schematic cross-sectional views for explaining a method for manufacturing the bearing 1. When manufacturing the bearing 1, first, as shown to Fig.3 (a), the outer race 2 and the inner race 3 are each shape | molded by press work.

  Next, as shown in FIG. 3B, the guide wall 23 and the guide wall 24 are integrally formed on the inner peripheral surface of the outer race 2. A guide wall 33 and a guide wall 34 are integrally formed on the outer peripheral surface of the inner race 3.

  Next, as shown in FIG. 4A, the inner side of the outer race 2, the inner race 3 is moved toward one side, and the other side where the gap between the inner race 3 and the outer race 2 is increased. A plurality of balls 4 are inserted into. At this time, the seal portion 25 of the outer race 2 and the seal portion 35 of the inner race 3 are deformed.

  Next, as shown in FIG. 4B, the ball 4 is moved in the circumferential direction of the bearing 1, and the retainer 5 is inserted when the centers of the diameters of the inner race 3 and the outer race 2 substantially coincide with each other. Are fixed at equal intervals in the circumferential direction. Note that when the retainer 5 is inserted, the seal portion 25 of the outer race 2 and the seal portion 35 of the inner race 3 are deformed. The bearing 1 is manufactured by the above process.

  In the above manufacturing process, when the seal portion 25 of the outer race 2 and the seal portion 35 of the inner race 3 are deformed, the elasticity of the elastomer of the seal portions 25 and 35 is used, so that the seal portions 25 and 35 are not plastically deformed. . Therefore, the contact pressure and contact state of the lip portion 26 and the lip contact surface 37 and the lip portion 36 and the lip contact surface 27 are uniform, and stable sealing performance is maintained.

  In the present embodiment, since the inner race 3 and the outer race 2 are made of metal, the sliding portions 22 and 32 between the inner race 3 and the outer race 2 and the ball 4 when the ball 4 rolls are made of metal. Therefore, higher accuracy and higher durability can be achieved as compared with the resin one, and the rotation accuracy of the ball 4 is also improved.

  Further, the guide walls 23 and 24 and the guide walls 33 and 34 for determining the position of the ball 4 in the thrust direction are formed by an elastomer, so that a disturbance or the like is applied to the rotating shaft supported by the bearing 1 so that the ball 4 is moved in the thrust direction These members function as cushioning materials when moved slightly. Therefore, the generation of noise during rotation is suppressed, leading to noise reduction.

  The general manufacturing process of a sealed bearing is a process of pressing, turning, ball insertion, retainer insertion, and seal insertion. On the other hand, in the bearing 1 of this embodiment, the sealing portions 25 and 35 are integrally formed with the outer race 2 and the inner race 3, so that the insertion process of the sealing portions 25 and 35 can be omitted, and the number of manufacturing steps is reduced. ing. Therefore, it is advantageous in terms of the number of processes as compared with a general sealed bearing manufacturing process.

  As described above, according to the configuration of the present embodiment, it is possible to provide the bearing 1 with a simple configuration and high accuracy and high durability, and having a stable sealing performance.

  In addition, in this embodiment, although the seal parts 25 and 35 are mutually extended | stretched from the both sides of the outer race 2 and the inner race 3, this invention is not restricted to this, It is the structure extended from any one at least. If there is, the same effect as described above can be obtained.

  In this embodiment, although the bearing 1 is used as the bearing portion of the rotating shaft 65a of the stirring member 65 provided in the electrophotographic image forming apparatus A, a drive transmission system other than the image forming apparatus and other rotating members are pivotally supported. Can also be used.

  In the present embodiment, a ball bearing is exemplified as the bearing 1, but the bearing 1 according to the present invention does not need to limit the rolling element to the ball 4, and may be composed of other members such as a roller.

1 ... Bearing 2 ... Outer race (outer ring)
3 ... Inner race (inner ring)
4 ... Ball (rolling element)
22 ... sliding part 23 ... guide wall (guide member)
24 ... Guide wall (guide member)
25 ... Seal part 27 ... Lip contact surface (groove part)
32 ... sliding part 33 ... guide wall (guide member)
34 ... Guide wall (guide member)
35 ... seal part 37 ... lip contact surface (groove part)
51 ... Photosensitive drum (image carrier)
54. Developing device (developing means)
65. Stirring member (rotating member)
A: Image forming apparatus S: Sheet (recording medium)

Claims (6)

In a bearing in which a plurality of rolling elements are arranged in a gap between a metal inner ring and a metal outer ring, and one of the inner ring and the outer ring moves relative to the other by rolling the rolling element.
Position of the rolling element with respect to the inner ring or the outer ring by forming a convex portion around a sliding portion between the rolling element and the inner ring or the outer ring, which is provided on at least one of the inner ring and the outer ring. A bearing member comprising: a guide member formed of an elastomer that includes a seal portion that extends to one of the inner ring and the outer ring and seals the gap.   The bearing according to claim 1, wherein the guide member determines a position in a thrust direction of the rolling element with respect to the inner ring or the outer ring.   The bearing according to claim 1, wherein the seal portion is in contact with a groove portion provided in the inner ring or the outer ring with a predetermined contact pressure.   The bearing according to claim 3, wherein the groove is disposed on a side surface of the inner ring or the outer ring. In an image forming apparatus for forming an image on a recording medium,
An image forming apparatus using the bearing according to claim 1 for a shaft support portion of a rotating member included in the image forming apparatus. An image carrier;
Developing means for supplying a developer to the image carrier and performing development,
The image forming apparatus according to claim 5, wherein the rotating member is a stirring member that stirs a developer used for development of the developing unit.

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