JP2014231861A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the low torque of rotation by preventing the intrusion of dust into a bearing.SOLUTION: The rolling bearing has an inner ring and an outer ring, a plurality of rolling bodies which are rollably arranged between the inner ring and the outer ring, and a cage for holding the rolling bodies. The outer ring is used as a rotating ring. The rolling bearing also comprises a non-contact type sealing device which blocks a clearance between the inner ring and the outer ring at its both ends in an axial direction, and grease which is provided in a space surrounded with the inner ring, the outer ring, the rolling bodies and the sealing device. The grease is located in the vicinity of the sealing device at the external peripheral face of the inner ring.

Description

  The present invention relates to a rolling bearing in which grease is filled only in a partial internal space of the rolling bearing.

  Rolling bearings used in an environment where fine dust is present, when fine dust enters the inside of the rolling bearing, damages the rolling surface including the ball rolling surface, inner ring, outer ring raceway surface, etc. There is a risk of deteriorating the function of the bearing. In addition, if dust or wear powder is mixed in the lubricating grease filled in the bearing, the grease may be deteriorated. If the rolling surface is damaged or the grease deteriorates, abnormal noise may be generated and seizure may occur.

  In order to improve the dust resistance of the bearing, for example, in Patent Document 1, in a bearing that employs a shield plate, a groove is provided on the outer peripheral surface of the inner ring, and grease is accumulated in the groove by utilizing centrifugal force. There was a proposal to close the gap between the inner ring and the inner ring. In addition, since the present invention uses the centrifugal force generated by the inner ring rotation, it is specified as a bearing for inner ring rotation such as a cooling fan motor.

JP 2004-218789 A

  Recently, bearings used in office machines such as copying machines and printers and ATMs are strongly demanded for low torque and low cost, and rolling bearings used for paper feeding mechanisms (feeders) of office machines are required to have dustproof performance. In order to improve dustproof performance, rubber contact seals are usually used for bearings.

  However, if a contact seal is used, the rotational torque of the bearing due to contact increases, and paper or banknotes are twisted, causing a paper jam or the like. Further, if dust or the like generated from paper or banknotes enters the bearing, problems such as defective rotation occur.

Therefore, in order to solve the above-described problems, the present invention provides (1) an inner ring and an outer ring, a plurality of rolling elements arranged to roll between the inner ring and the outer ring, and a cage that holds the rolling elements. A rolling bearing in which the outer ring is used as a rotating ring, and is surrounded by a non-contact type sealing device that closes the inner ring and the outer ring at both axial ends, and an inner ring, an outer ring, a rolling element, and a sealing device. There is provided a rolling bearing including a grease disposed in a space, wherein the grease is located in the vicinity of the sealing device on the outer peripheral surface of the inner ring.
(2) The grease is characterized by being disposed at both axial ends of the outer peripheral surface of the inner ring.
(3) The volume of the grease is 25% to 30% by volume of the space volume.
(4) The grease has a miscibility of 220 to 250 at 25 ° C.
(5) The grease is located in the vicinity of the sealing device on the outer peripheral surface of the inner ring before the bearing rotation is started.
Since the rolling bearing of the present invention is a semi-solid grease, the position of the grease is not substantially changed before the operation is started, and when the shield plate is opened, it can be confirmed that the vicinity of the shield plate is filled.
Furthermore, if the grease having a blending consistency at 25 ° C. of (4) of 220 or more and 250 or less (that is, corresponding to NLGI consistency number No. 3) is used, the conventional consistency (NLGI consistency number No. 3) is used. .2) It is harder than grease and can exhibit lubricating performance and has higher dustproof performance, which is preferable.
In addition, when grease is filled in both axial ends of the bearing, the application volume on the cage 4 opening side is about 50 to 60% of the total volume, and the application volume on the opposite side of the cage 4 opening is It is preferable to be about 40 to 50% of the total volume.

  The rolling bearing of the present invention can close the gap between the sealing device and the outer peripheral surface of the inner ring by filling the vicinity of the non-contact type sealing device with grease, and suppresses the entry of external dust into the bearing. it can. Furthermore, since the grease is located on the inner ring side where it does not rotate, grease scattering to the outside of the bearing due to rotation of the outer ring of the bearing does not occur.

It is sectional drawing which shows the ball bearing which concerns on 1st Embodiment. It is a figure corresponding to the AA cross section of FIG. It is sectional drawing which shows the ball bearing which concerns on 2nd Embodiment. It is a figure corresponding to the AA cross section of FIG.

[First Embodiment]
FIG. 1 is a sectional view showing a ball bearing corresponding to the first embodiment of the present invention. FIG. 2 is a view corresponding to the AA cross section of FIG. The ball bearing includes an inner ring 1, an outer ring 2, a ball 3, a cage 4, a shield plate 50, and grease 6. The dimensions of this ball bearing are an outer diameter of 12 to 22 mm, an inner diameter of 5 to 8 mm, a width of 3.5 to 7 mm, and a ball diameter of 1.2 to 4 mm. A rolling groove 12 for the ball 3 is formed in the axially central portion of the outer peripheral surface 11 of the inner ring 1. A rolling groove 22 for the ball 3 is formed in the central portion in the axial direction of the inner peripheral surface 21 of the outer ring 2. Mounting grooves 23 for the shield plate 50 are formed at both axial ends of the inner peripheral surface 21 of the outer ring 2. The cage 4 is a crown-shaped cage made of a synthetic resin, and has a pocket 41 opened on one side in the axial direction.

  The shield plate 50 is made of metal, and the inner peripheral edge portion of the shield plate 50 is a proximity portion 501 that is close to the outer peripheral surface 11 of the inner ring 1 with a predetermined gap. The outer peripheral edge portion of the shield plate 50 is a fixing portion 52 that is fixed to the attachment groove 23 formed on the inner peripheral surface 21 of the outer ring 2.

  As shown in FIG. 1, the grease 6 is on the opening side of the cage 4 in the space (bearing space) surrounded by the inner ring 1, the outer ring 2, the balls 3, and the shield plate 50, and the outer circumferential surface of the inner ring 1. It is applied in the vicinity of the shield plate 50 of the (non-rotating wheel) 11. It is similarly applied to the space on the opposite side to the opening of the cage 4.

  As shown in FIG. 2, the grease 6 is applied to the outer peripheral surface 11 of the inner ring 1 and is not applied to the inner peripheral surface 21 of the outer ring 1. Before the shield plate 50 is attached, the grease 6 is applied from the end in the axial direction over the entire circumferential direction of the outer peripheral surface 11 of the inner ring 1 using, for example, a nozzle having a plurality of holes. Spherical grease 6 is disposed without gaps. Thereby, the grease is arranged in a bead shape in the circumferential direction. In this application method, since a conventional grease filling device can be used, new equipment is not required, and production costs are not increased. The blending degree of the grease 6 is 230, and the total volume of the grease 6 applied to both ends in the axial direction is 26% by volume of the bearing space. In addition, when preloading the bearing, the internal clearance of the bearing tends to be small, so that grease may be applied to the back surface of the pocket 41 of the cage. In this case, since the rotation of the bearing is increased, it is preferable to apply a relatively small amount of grease to the opposite side of the opening of the cage 4 in advance. The application volume at one end of the cage 4 opening side is approximately 60% of the total volume, and the application volume on the opposite side of the cage 4 opening is approximately 40% of the total volume.

  The ball bearing of the present embodiment can close the gap between the shield plate 50 and the outer peripheral surface 11 of the inner ring 1 by applying the grease 6 closer to the shield plate 50, and the dust intrusion from the outside is suppressed. The

  The ball bearing of this embodiment is a miniature ball bearing with a narrow bearing space, and the internal clearance is MC3 (5 to 10 μm) conforming to the JIS standard, but the outer peripheral surface of the inner ring 2 (non-rotating ring). 11 is not affected by centrifugal force due to rotation, and the grease is not easily crushed. Further, since the grease 6 is applied in the vicinity of the shield plate 50, even when a preload is applied and an axial displacement occurs in the inner and outer rings, the grease 6 is difficult to contact the ball 3. Therefore, the grease 6 is not easily crushed even when a preload is applied to the ball bearing. Therefore, according to the ball bearing of this embodiment, the amount of grease 6 entering the raceway grooves 12 and 13 of the inner and outer rings is reduced even in a state where a preload is applied, so that an increase in rotational torque is suppressed.

[Second Embodiment]
FIG. 3 is a cross-sectional view showing a ball bearing according to a second embodiment of the present invention. FIG. 4 is a view corresponding to the AA cross section of FIG. This ball bearing is different from the ball bearing of the first embodiment in the following points, but the other points are the same as the ball bearing of the first embodiment.

  The internal clearance of the ball bearing employs an MC2 (3 to 8 μm) clearance that conforms to JIS standards. In the present embodiment, an annular grease 6 is disposed on the outer peripheral surface 11 of the inner ring 1. The outer peripheral surface of the annular grease 6 is in contact with the outer peripheral surface 11 of the inner ring 1. The total application volume of grease 6 at both ends in the axial direction is 29% by volume of the bearing space, and the application volume at each of both ends is about 50% of the total volume.

  Before the shield plate 50 is attached, the grease 6 is applied from the opening side of the cage 4 by using, for example, a nozzle having one hole, and rotating the inner ring 1 of the nozzle or ball bearing while rotating the outer ring 1 of the inner ring 1. It is performed by discharging grease from the nozzle over the entire circumferential direction of the surface 11. As a result, the grease 6 is applied in an annular shape without a break across the entire circumferential direction of the outer peripheral surface 11 of the inner ring 1. Thereby, the grease is arranged in an annular shape in the circumferential direction.

  Therefore, according to the ball bearing of this embodiment, like the ball bearing of the first embodiment, the grease 6 is applied closer to the shield plate 50 so that the gap between the shield plate 50 and the outer peripheral surface 11 of the inner ring 1 is increased. The gap can be closed, and dust intrusion from the outside is suppressed. Even in the state where the preload is applied, the amount of the thickener contained in the grease 6 enters the raceway grooves 12 and 13 of the inner and outer rings is reduced, so that an increase in rotational torque is suppressed.

DESCRIPTION OF SYMBOLS 1 Inner ring 11 Outer ring surface of inner ring 12 Rolling groove 2 Outer ring 21 Inner ring surface of outer ring 22 Rolling groove 23 Mounting groove of shield plate 3 Ball 4 Cage 41 Pocket 5 Shield plate 6 Grease

Claims (5)

A rolling bearing that includes an inner ring and an outer ring, a plurality of rolling elements that are rotatably arranged between the inner ring and the outer ring, and a cage that holds the rolling element, and the outer ring is used as a rotating ring. Because
A non-contact type sealing device that seals between the inner ring and the outer ring at both axial ends, and grease disposed in a space surrounded by the inner ring, the outer ring, the rolling element, and the sealing device, Is located in the vicinity of the sealing device on the outer peripheral surface of the inner ring.   The rolling bearing according to claim 1, wherein the grease is disposed at both axial ends of the outer peripheral surface of the inner ring.   The rolling bearing according to claim 1, wherein a volume of the grease is 25% to 30% by volume of the space volume.   The rolling bearing according to any one of claims 1 to 3, wherein the grease has a penetration degree of 220 to 250 at 25 ° C.   The rolling bearing according to any one of claims 1 to 4, wherein the grease is positioned in the vicinity of the sealing device on the outer peripheral surface of the inner ring before the bearing starts rotating.

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