SEALED BEARING ASSEMBLY

Abstract

Disclosed is a sealed bearing arrangement that provides at least a bearing with an outer ring and an inner ring, which are rotatable to each other and form a rolling chamber between each other, in which a set of rolling elements. A lubricant is encompassed in the rolling chamber and the rolling chamber is sealed off from an environment by at least one sealing element. The inner ring, the outer ring and/or the sealing element includes at least one opening for providing a fluid passage through the sealing element. The bearing is arranged in a housing that is adapted to seal off the bearing from an outside environment. A lubricant is encompassed inside the housing. The housing including the at least one opening for providing a fluid passage from the inside of the housing to the outside. The opening is fluid tightly connected to an oxygen removing element and/or to a gas tank, which provides an oxygen poor to free fluid flow to the rolling chamber.

Claims

1. A sealed bearing arrangement comprising: at least a bearing with an outer ring and an inner ring that are rotatable with respect to each other and form a rolling chamber between each other, in which a set of rolling elements is arranged, wherein a lubricant is encompassed in the rolling chamber and the rolling chamber is sealed off from an environment by at least one sealing element, wherein the inner ring, the outer ring and/or the sealing element further comprises at least one opening for providing a fluid passage through the sealing element, wherein the opening is fluid tightly connected to an oxygen removing element and/or to a gas tank, which provides an oxygen poor to free fluid flow to the rolling chamber.

2. A sealed bearing arrangement comprising: at least a bearing with an outer ring and an inner ring that are rotatable to each other and form a rolling chamber between each other, in which a set of rolling elements is arranged, wherein the bearing is arranged in a housing, which is adapted to seal off the bearing from an outside environment, and wherein a lubricant is encompassed inside the housing, wherein the housing further comprises at least one opening for providing a fluid passage from the inside of the housing to the outside, wherein the opening is fluid tightly connected to an oxygen removing element and/or to a gas tank, which provides an oxygen free fluid flow to the inside of the housing.

3. The sealed bearing arrangement according to claim 1, wherein the oxygen removing element comprises a material which is adapted to absorbs oxygen and releases absorbed oxygen based on a change of at least one physical parameter which im-pacts on the oxygen removing element.

4. The sealed bearing arrangement according to claim 1, wherein the physical parameter is temperature and/or pressure.

5. The sealed bearing arrangement according to claim 1, wherein the oxygen removing element comprises a honeycomb structure or similar structure or big surface generating structure.

6. The sealed bearing arrangement according to claim 1, wherein the oxygen removing element comprises zeolite and/or activated carbon and/or activated graphite.

7. The sealed bearing arrangement according to claim 1, wherein the gas tank comprises nitrogen.

8. The sealed bearing arrangement according to claim 1, wherein the lubricant is grease.

Description

[0020] The figures show:

[0021] FIG. 1: a schematic sectional view of a bearing assembly according to a first embodiment of the present invention;

[0022] FIG. 2: a schematic sectional view of an oxygen removing; and

[0023] FIG. 3: a schematic sectional view of a bearing assembly according to a second embodiment of the present invention.

[0024] In the following same or similar functioning elements are indicated with the same reference signs.

[0025] FIG. 1 shows a schematic sectional view of a bearing assembly 1. The bearing assembly 1 comprises a bearing 2 which is housed in a housing 4. The bearing 2 supports a shaft 6. As can be further seen in FIG. 1, the housing 4 seals off the bearing 2 from an outside environment 8. The in the space 10 of the housing 4, in which also the bearing 2 is accompanied, a lubricant, such as the grease, is provided.

[0026] For allowing a pressure equalization with the outside environment 8, the housing 4 is further equipped with openings 12, which allow an air flow from the inside of the housing to the outside and vice versa. Since such an airflow also provides fresh oxygen to the inner space 10, which in turn might oxidized the lubricant, at least one oxygen removing element 14 is arranged in the/at the opening 12. The oxygen removing element 14 is illustrated in FIG. 2 and preferably has a honeycomb structure. Such are oxygen removing element may be made from zeolite, activated carbon, activated graphite or any other oxygen absorbing/desorbing material with a surface increasing structure.

[0027] The oxygen removing feature of such bearing assembly 1 works as follows:

[0028] During operation the bearing 2 heats up, which in turn increases also the temperature inside of the housing 4. Consequently, also the air and/or the lubricant present inner space 10 of the housing 4 heats up which results in an expansion and a pressure increase. Due to the pressure increase air is pressed through the opening 12 and thereby through the oxygen removing element 14. Preferably, the oxygen removing element has an oxygen desorbing property with increased temperature so that oxygen is transported from the inner space 10 of the housing 10 as well as from the oxygen removing element 14 to the outside environment 8.

[0029] As soon the operation of the bearing 2 is terminated, the temperature decreases and the bearing assembly 1 cools down. This in turn results in a pressure decrease in the inner space 10 of the housing 4 which reverses the gas flow through the opening 12 and the oxygen removing element 14. In case the oxygen removing element is made e.g. from a material with oxygen removing properties at lower temperatures, then the oxygen is removed from the air streaming through the gas removing element 14 and the opening 12. Consequently, the oxygen amount in the inner space 10 of the housing 4 is reduced, which in turn reduces the oxidation of the lubricant inside the housing and increases the service life of the lubricant and/or of the bearing.

[0030] FIG. 3 shows a sectional view of a further embodiment of a bearing assembly of the present invention. A bearing assembly 1 is illustrated having an outer ring 16 and an inner ring 18 which define a rolling chamber 20 between each other. In the rolling chamber 20 rolling elements 22 are arranged. As can be further seen from FIG. 3, the rolling elements 22 are maintained by a cage 24 in a regularly spaced apart condition and the rolling chamber 20 is sealed off from the environment 8 by a sealing element 26. In the illustrated embodiment, the sealing element 26 is fixed to the outer ring 16 and in gliding contact to the inner ring 18 with lip 28.

[0031] During operation of the bearing 1, the temperature in the rolling chamber 20 increases which results in a pressure increase inside of the rolling chamber 20. In known bearings such a pressure increase triggers a lifting off of the lip 28 of the sealing element 26 from the gliding surface of the inner ring 18 for balancing the pressure difference and releasing air from the rolling chamber 20. After the operation of the bearing has been stopped the bearing cools down, which results in low pressure in the rolling chamber 20, which is also balanced by air being transported over the sealing lip 28.

[0032] For avoiding the lifting motion of the sealing lip 28 triggered by the pressure differences, it is proposed to provide an opening in the sealing element 26 in which at oxygen removing element 14 is arranged and/or with which a gas tank 30 is connected. This allows for an air exchange over the oxygen removing element, which reduces the overall oxygen the amount in the rolling chamber, as explained above. Instead of providing the opening in the sealing element, it is also possible to provide the opening in the inner and/or altering.

[0033] In case a gas tank is fluid tightly connected to the opening of the sealing element, the air is not equipped with fresh oxygen from the outside environment 8, but with an oxygen free gas, such as nitrogen, which also reduces the oxidation of the lubricant in the rolling chamber. The size of the gas tank may be adapted to the expected pressure differences and the expected air exchange through the sealing element. Of course, such a gas tank may also be provided to the housing illustrated in FIG. 1 and in addition to any oxygen removing element.

[0034] This embodiment has a further benefit as the extensive wear due to the lifting off motion of the sealing lip is avoided. This in turn allows for an increase service life of the sealing element and therefore of the bearing.

[0035] As can be further seen in the FIG. 1 and FIG. 3, the bearing is not restricted to a certain embodiment of the bearing so that any bearing, e.g. a roller bearing, such as a tapered roller bearing or any kind of ball bearing, may be used with this invention.

[0036] In summary the oxygen removing element as well as the gas tank allows for an air exchange in the bearing without adding fresh oxygen to the inside of the bearing or the housing. This in turn, allows for the reduced oxidation of the lubricant and thereby for an increased service life of the grease/the bearing.