Needle roller bearing

Abstract

Disclosed is a needle roller bearing, in particular for use in supporting a bottom roller in a spinning machine. The needle roller bearing includes an inner ring and an outer ring which are arranged such that the inner ring and the outer ring are rotatable relatively to each other around a bearing rotation axis. A rolling chamber is defined between the inner ring and the outer ring, in which a plurality of needle rollers are arranged. A solid lubricant is disposed in the rolling chamber of the needle roller bearing.

Claims

1. A needle roller bearing for use in supporting a bottom roller in a spinning machine, the needle roller bearing comprising: an inner ring and an outer ring configured such that the inner ring and the outer ring are rotatable relatively to each other around a bearing rotation axis, wherein a rolling chamber is defined between the inner ring and the outer ring, in which a plurality of needle rollers is arranged, and a solid lubricant is disposed in the rolling chamber of the needle roller bearing, the solid lubricant comprising a porous structure, the porous structure comprising pores having a pore size ranging from 1-10 μm, the inner ring further comprises an outermost lateral face and the solid lubricant contacts the outermost lateral face.

2. The needle roller bearing according to claim 1, wherein the solid lubricant is configured to fill the rolling chamber in such a way that the needle rollers can rotate freely in the rolling chamber.

3. The needle roller bearing according to claim 1, wherein the solid lubricant comprises a support material, the support material comprising the porous structure.

4. The needle roller bearing according to claim 3, wherein the porous structure is saturated with a lubricant oil.

5. The needle roller bearing according to claim 4, wherein the solid lubricant is configured to release the retained lubricant oil during an operation of the needle roller bearing.

6. The needle roller bearing according to claim 3, wherein the support material is made from a polymer material.

7. The needle roller bearing according to claim 1, wherein each of the plurality of needle rollers are space apart from each other by a cage.

8. A bottom roller bearing for supporting a bottom roller in a spinning machine, the bottom roller bearing comprising: at least one needle roller bearing including an inner ring and an outer ring configured such that the inner ring and the outer ring are rotatable relatively to each other around a bearing rotation axis, the inner ring comprising a first lateral side and a second lateral side, wherein a rolling chamber is defined between the inner ring and the outer ring, in which a plurality of needle rollers is arranged, and a solid lubricant is disposed in the rolling chamber of the needle roller bearing, the solid lubricant extending over the first lateral side and the second lateral side, the inner ring further comprises an outermost lateral face and the solid lubricant contacts the outermost lateral face.

9. A needle roller bearing for use in supporting a bottom roller in a spinning machine, the needle roller bearing comprising: an inner ring and an outer ring configured such that the inner ring and the outer ring are rotatable relatively to each other around a bearing rotation axis, the inner ring having an inner axial length, the outer ring having an outer axial length, the inner axial length being shorter than the outer axial length, wherein a rolling chamber is defined between the inner ring and the outer ring, in which a plurality of needle rollers is arranged, and a solid lubricant is disposed in the rolling chamber of the needle roller bearing, the solid lubricant comprising a porous structure, the porous structure comprising pores having a pore size ranging from 1-10 μm, the inner ring further comprises an outermost lateral face and the solid lubricant contacts the outermost lateral face.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, preferred embodiments of the invention are described in relation to the drawings, wherein the drawings are exemplarily only, and are not intended to limit the scope of protection. The scope of protection is defined by the accompanied claims, only.

(2) The figures show:

(3) FIG. 1: a cross-section of a needle roller bearing according to an embodiment, and

(4) FIG. 2: a schematic view of a bottom roller bearing according to another embodiment.

(5) In the following same or similar functioning elements are indicated with the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows a cross section of a needle roller bearing 1. The needle roller bearing 1 comprises an inner ring 2 and an outer ring 4. The inner ring 2 and the outer ring 4 are arranged concentrically to each other and in such a way that the inner ring 2 and the outer ring 4 are rotatable relatively to each other around a bearing rotation axis 6. In FIG. 1, the inner ring 2 is mounted as a rotatable inner ring onto a shaft, for example a bottom roller 22 (FIG. 2), whereas the outer ring 4 is fixed. Furthermore, the inner ring 2 has a flange 3 at each axial side. The flange 3 of the inner ring 2 may have a first lateral side and second lateral side. The inner ring may further comprise at least one outermost lateral face.

(7) The needle roller bearing 1 includes a plurality of needle rollers 8, which are disposed in a rolling chamber being defined between the inner ring 2 and the outer ring 4. The needle rollers 8 are configured to roll on raceways (not referenced) that are provided on both the inner ring 2 and the outer ring 4. Additionally, the needle rollers 8 of the needle roller bearing are held by a cage 10. The cage 10 is configured as a split cage so that the cage 10 can be mounted over the inner ring flanges 3. Furthermore, a fixation plate 12 is provided at the outer ring 4 which allows for an axial fixation of the bearing.

(8) To prevent particles, particularly fiber particles, from entering the needle roller bearing 1, a solid lubricant 14 is disposed in the rolling chamber of the needle roller bearing 1. The solid lubricant 14 fills the whole rolling chamber in such a way that it essentially covers the needle rollers 8 and the cage 10. The solid lubricant 14 may extend over the first lateral side and the second lateral side of the inner ring 2. In some embodiments, the solid lubricant 14 may contact at least one outmost lateral face of the inner ring 2. For allowing a free rotation of the needle roller bearing 1, very narrow openings or gaps are left between the needle rollers 8 and raceways on which the needle rollers 8 are rolling.

(9) The solid lubricant 14 according to the embodiment shown in FIG. 1 is made from a polymer material which acts as a support material and has a porous structure, which is saturated with a lubricant oil. The lubricant oil is retained by surface tension in the porous structure of the solid lubricant 14. Due to the rotation of the needle roller bearing 1 during operation, the contained lubricant is released and can provide an effective minimum quantity lubrication for the needle roller bearing 1.

(10) In FIG. 2, a bottom roller bearing 20 is shown that is supporting a bottom roller 22 that is for example arranged in a spinning machine. The bottom roller bearing 20 includes a needle roller bearing 1 as shown in FIG. 1. The bottom roller 22 is mounted on the inner ring 2 of the needle roller bearing 1, which is configured as a rotating ring. Furthermore, the inner ring 2 has flanges 3 on both axial sides of the bearing 1 in order to prevent entry of fibers in the bearing and protect it from damage.

(11) The outer ring 4 of the needle roller bearing 1 is configured as a stationary ring. A bottom part of the outer ring 4 seated in a holding fixture 24 of the spinning machine. The holding fixture 24 of FIG. 2 covers the bottom part (approx. 180°) of the outer ring 4 and retains the bearing radially. Since the bottom rollers 22 are pressed down by a top roller 28 during operation of the spinning machine, an upward fixation of the bottom roller bearing 20 is not needed.

(12) The fixation plate 12, which also covers only a part of the outer ring 4 provides an axial fixation. In the embodiment shown in FIG. 2, this is achieved with noses 26 (only one is shown) that extend radially over the axial side of the bearing and abut on an axial outer side of the holding fixture 24.

(13) In summary a close osculation between the solid lubricant 14 and the needle rollers 8 and the raceways can significantly reduce the amount of contaminants that are accumulated in the needle roller bearing 1 as the solid lubricant also acts as a seal. Furthermore, lubricant oil that is retained in the solid lubricant 14 may make a relubrication of the needle roller bearing 1 unnecessary. This further reduces the effort and material cost for the maintenance of the needle roller bearing and allows for almost maintenance free needle roller bearing 1.