JP7528493B2 - Rolling bearing and bearing device - Google Patents

Description

The present invention relates to rolling bearings and bearing devices.

The photosensitive drum of a general information device, for example a copying machine, is repeatedly charged and de-charged to produce an image. Specifically, the surface of the photosensitive drum is first charged with static electricity by a charging electrode, and then the image of the original is exposed to the surface of the photosensitive drum by a lamp and optical system. As a result, the static electricity in the exposed area (white area of the original) is de-charged by the light, and the image area remains charged. Next, when toner is supplied to the surface of the photosensitive drum, the toner adheres to the charged area of the surface of the photosensitive drum and the image appears. The toner adhered to the surface of the photosensitive drum is transferred to the copy paper by a transfer electrode, and the toner (image) transferred to the copy paper is fixed to the copy paper by heat and pressure and discharged. Meanwhile, the static electricity on the surface of the photosensitive drum is de-charged by a de-charging electrode in preparation for the next copy.

As this charging and de-charging is repeated, the photosensitive drum becomes statically charged. A rolling bearing is directly connected to the photosensitive drum, and it is known that when current flows through the contact area between the raceway and the rolling element, sparks occur through the thin lubricating oil film, causing the surface to melt locally and become uneven, i.e., electrolytic corrosion. As a countermeasure to this, it is widely practiced to pass electricity between the inner and outer rings using a conductive member such as a metal brush, as shown in Patent Document 1, for example.

Microfilm of Utility Model Application No. 02-50355 (Utility Model Application No. 04-8820)

One end of a conductive member such as a metal brush is attached to the inner surface of the outer ring and hangs down toward the inner ring, with the other end attached so that it slides against the outer surface of the inner ring. As a result, the distance between the conductive member and the raceway surface is short, which can cause contamination from the conductive member to get into the bearing and degrade the lubrication performance.

The present invention was made in consideration of these circumstances, and aims to prevent contamination from conductive members such as metal brushes from entering the inside of a rolling bearing equipped with such conductive members.

The above problems are solved by the following rolling bearing and bearing device according to the present invention.
(1) A rolling bearing comprising an inner ring having an inner ring raceway surface on its outer peripheral surface, an outer ring having an inner peripheral surface, an outer peripheral surface and a side end surface and having an outer ring raceway surface on the inner peripheral surface, and a plurality of rolling elements held between the inner ring raceway surface and the outer ring raceway surface so as to be able to roll freely, the rolling bearing being assembled into a bearing device,
a rolling bearing comprising a conductive member extending from at least one of the inner circumferential surface, the outer circumferential surface, and the side end surface of the outer ring to the outer circumferential surface of a shaft of the bearing device that is electrically conductive with the inner ring, thereby providing electrical conductivity between the outer ring and the shaft.
(2) The rolling bearing according to (1) above;
The shaft that is fitted onto the inner ring of the rolling bearing;
a housing that is fitted onto the outer ring of the rolling bearing;
A bearing device comprising:
(3) A rolling bearing having an inner peripheral surface, an outer peripheral surface and a side end surface, the inner ring having an inner ring raceway surface on the outer peripheral surface, an outer ring having an outer ring raceway surface on the inner peripheral surface, and a plurality of rolling elements held between the inner ring raceway surface and the outer ring raceway surface so as to be able to roll freely, the rolling bearing being assembled into a bearing device,
a rolling bearing comprising a conductive member extending from at least one of the inner circumferential surface, the outer circumferential surface, and the side end surface of the inner ring to an inner circumferential surface of a housing of the bearing device that is electrically conductive between the inner ring and the outer ring, thereby providing electrical conductivity between the inner ring and the housing.
(4) The rolling bearing according to (3) above,
a shaft that fits into the inner ring of the rolling bearing;
The housing is fitted onto the outer ring of the rolling bearing;
A bearing device comprising:

According to the present invention, in a rolling bearing equipped with a conductive member such as a metal brush, it is possible to prevent contamination from the conductive member from entering the inside of the bearing.

FIG. 1 is a cross-sectional view showing a first embodiment of a rolling bearing according to the present invention. FIG. 2 is a cross-sectional view showing a rolling bearing according to a second embodiment of the present invention.

The present invention will now be described in detail with reference to the drawings.

First Embodiment
FIG. 1 is a cross-sectional view showing a first embodiment of a rolling bearing according to the present invention. As shown in the figure, the rolling bearing 1 includes an inner ring 7 having an inner ring raceway 6 on its outer peripheral surface 5, and an outer ring 4 having an inner peripheral surface 2, an outer peripheral surface 41, and a side end surface 40, and having an outer ring raceway 3 on its inner peripheral surface 2. A plurality of rolling elements 8 are held by a cage 9 so as to be freely rollable between the inner ring raceway 6 and the outer ring raceway 3. In addition, the gaps at both ends between the inner ring 7 and the outer ring 4 are sealed by a pair of seals 10, 10, and grease or lubricating oil (not shown) is sealed in the bearing space formed by the seals 10, 10 and the rolling elements 8. Note that, in FIG. 1, the pair of seals 10, 10 are of a contact type having substantially no gap between the inner ring 7 or the outer ring 4 and the seal 10, but may be of a non-contact type having a predetermined gap between the inner ring 7 or the outer ring 4 and the seal 10.

The inner ring 7 is fitted with the shaft 20 of the bearing device, and in this embodiment, the inner ring 7 rotates as the shaft 20 rotates. The outer ring 4 is fitted with the housing 30 of the bearing device. In this way, the rolling bearing 1 is assembled in a fitted state between the shaft 20 and the housing 30 of the bearing device. Furthermore, by fitting the inner ring 7 with the shaft 20, the inner ring 7 and the shaft 20 are electrically connected.

In this embodiment, as an example, a conductive member 50 is attached to one side end surface 40 of the outer ring 4 (the right side in the example of FIG. 1). As shown in the figure, the conductive member 50 is a member with a substantially L-shaped cross section, which includes a cylindrical protruding portion 51 that extends from the side end surface 40 of the outer ring 4 and protrudes outside the bearing, and a disk-shaped standing portion 52 that bends from the protruding portion 51 and faces the shaft 20, and an end portion 53 of the standing portion 52 abuts against the outer peripheral surface 21 of the shaft 20. Therefore, for example, when static electricity (leakage current) generated in the housing 30 flows to the contact portion between the outer ring raceway surface 3 and the rolling element 8 in the rolling bearing 1, the static electricity is discharged by being conducted from the outer ring 4 to the shaft 20 through the conductive member 50. Note that the conductive member 50 can be a metal brush similar to that used in the past, but may also be, for example, a seal using conductive rubber. The conductive member 50 may be attached to the side end surface 40 by a method such as gluing or screwing.

In addition, there is a concern that wear powder will be generated from the end 53 of the conductive member 50 and the outer circumferential surface 21 of the shaft 20 as the shaft 20 rotates, and this will become contaminants and enter the inside of the bearing through the pair of seals 10, 10. However, in this embodiment, since the conductive member 50 has the protruding portion 51, the end 53 is separated from the outer ring 4 and the inner ring 7, and there is a sufficient distance between the rolling bearing 1 and the end 53 of the conductive member 50 where wear powder may be generated, so that it is possible to prevent wear powder from entering the inside of the bearing. The longer the protruding length L of the protruding portion 51, the better, and is appropriately determined taking into consideration the strength of the conductive member 50, the width of the entire bearing, and the like.
Furthermore, the radial thickness (the vertical direction in FIG. 1 ) of the protrusion 51 is not particularly limited, and may be approximately the same as the radial thickness of the outer ring 4, or may be thinner than that as long as the strength of the protrusion 51 is sufficiently ensured.

When the conductive member 50 is a seal made of the conductive rubber described above, the rolling bearing 1 can be combined with the seals 10, 10 to form a double seal structure, and the conductive member 50 can prevent contamination from entering the inside of the bearing while ensuring sealing inside the bearing.

Furthermore, although not shown, the conductive member 50 can start from the outer peripheral surface 41 of the outer ring 4, in addition to the side end surface 40 of the outer ring 4 described above. In that case, the protruding length L of the protruding portion 51 is made longer, and a part of it is attached to the outer peripheral surface 41 of the outer ring 4. Alternatively, as long as the outer ring 4 and the housing 30 are electrically conductive, a recess capable of accommodating the protruding portion 51 of the conductive member 50 may be formed in the housing 30. Furthermore, the conductive member 50 can also start from the inner peripheral surface 2 of the outer ring 4.
Furthermore, although not shown in the figures, the protrusion 51 of the conductive member 50 may be formed to span at least two of the inner surface 2, the outer surface 41, and the side end surface 40 of the outer ring 4.

Second Embodiment
In the first embodiment described above, the conductive member 50 is attached to the outer ring 4, but it is also possible to attach it to the inner ring 7. As shown in Fig. 2, the housing 30 of the bearing device is fitted to the outer ring 4, and this embodiment is an outer ring rotating type in which the outer ring 4 rotates together with the rotation of the housing 30. The inner ring 7 is fitted to the shaft 20 of the bearing device. In this manner, the rolling bearing 1 is assembled in a state of being fitted between the shaft 20 of the bearing device and the housing 30. Furthermore, by fitting the outer ring 4 into the housing 30, the outer ring 4 and the housing 30 are electrically connected.

In this embodiment, a conductive member 50 is attached to one side end surface 70 of the inner ring 7 (the right side in the example of FIG. 2). As shown in the figure, the conductive member 50 is a member with a generally L-shaped cross section, including a protruding portion 51 that protrudes from the side end surface 70 of the inner ring 7 to the outside of the bearing, and a standing portion 52 that bends from the protruding portion 51 toward the housing 30, and an end portion 53 of the standing portion 52 abuts against the inner peripheral surface 31 of the housing 30. Therefore, for example, when static electricity (leakage current) generated on the shaft 20 flows to the contact portion between the inner ring raceway surface 6 and the rolling element 8 in the rolling bearing 1, it is conducted from the inner ring 7 through the conductive member 50 to the housing 30 and is discharged.

In addition, there is a concern that wear powder will be generated from the end 53 of the conductive member 50 and the inner circumferential surface 31 of the housing 30 as the housing 30 rotates, and that this will become contaminants and enter the inside of the bearing via the pair of seals 10, 10. However, in this embodiment, since the conductive member 50 has the protrusion 51, the end 53 is separated from the outer ring 4 and the inner ring 7, and there is a sufficient distance between the rolling bearing 1 and the end 53 of the conductive member 50 where wear powder may be generated, it is possible to prevent wear powder from entering the inside of the bearing.
As in the first embodiment, the radial thickness (vertical direction in FIG. 1) of the protrusion 51 is not particularly limited, and may be approximately the same as the radial thickness of the inner ring 7, or may be thinner than that as long as the strength of the protrusion 51 is sufficiently ensured.

Also, as in the first embodiment, although not shown in the figures, the conductive member 50 can also start from the outer peripheral surface 5 or the inner peripheral surface 71 of the inner ring 7 in addition to the side end surface 70 of the inner ring 7 described above.
Furthermore, although not shown in the figures, the protrusion 51 of the conductive member 50 may be formed to span at least two of the inner surface 71, the outer surface 5, and the side end surface 70 of the inner ring 7.

In the present invention, there is no restriction on the type of rolling bearing 1, and the present invention can be applied to cylindrical bearings, etc., in which the rolling elements 8 are rollers other than the balls shown in the above embodiment. The present invention also includes a bearing device that includes the above-mentioned various rolling bearings 1, a shaft 20 that fits into the inner ring 7 of the rolling bearing 1, and a housing 30 that fits into the outer ring 4 of the rolling bearing 1.

1 Rolling bearing 2 Inner peripheral surface (of outer ring) 3 Outer ring raceway surface 4 Outer ring 5 Outer peripheral surface (of inner ring) 6 Inner ring raceway surface 7 Inner ring 8 Rolling element 9 Cage 10 Seal 20 Shaft 21 Outer peripheral surface of shaft 30 Housing 31 Inner peripheral surface of housing 40 Side end surface (outer ring side)
41 (Outer ring) outer peripheral surface 50 Conductive member 51 Protruding portion 52 Standing portion 53 End portion 70 Side end surface (inner ring side)
71 (of the inner ring) inner peripheral surface L: protruding length of the protruding part

Claims (2)

A rolling bearing comprising an inner ring having an inner ring raceway surface on its outer peripheral surface, an outer ring having an inner peripheral surface, an outer peripheral surface and a side end surface and having an outer ring raceway surface on the inner peripheral surface, a plurality of rolling elements held for free rollability between the inner ring raceway surface and the outer ring raceway surface, and a pair of seals provided in gaps formed at both ends of the inner ring and the outer ring, the rolling bearing being assembled into a bearing device,
a conductive member extending from at least one of the inner peripheral surface, the outer peripheral surface, and the side end surface of the outer ring to an outer peripheral surface of a shaft of the bearing device that is electrically conductive between the outer ring and the shaft, thereby electrically conducting the outer ring and the shaft;
the conductive member is attached to at least one of the inner circumferential surface, the outer circumferential surface, and the side end surface of the outer ring, and has a cylindrical protruding portion protruding axially outwardly of the outer ring, and a disk-shaped upright portion bent from the protruding portion and extending toward the axis,
an end of the standing portion, which is in sliding contact with the outer circumferential surface of the shaft and generates wear powder, and the seal, which is close to the conductive member, are separated in the axial direction ;
The conductive member is made of conductive rubber,
A rolling bearing comprising a double seal structure formed by combining the conductive member and the seal . A rolling bearing according to claim 1 ;
The shaft that is fitted onto the inner ring of the rolling bearing;
a housing that is fitted onto the outer ring of the rolling bearing;
A bearing device comprising:

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