WO2009033457A1 - Cage for accommodating a plurality of rolling elements of a rolling bearing and method for lubricating a rolling bearing - Google Patents

Abstract

The invention relates to a cage (1) for accommodating a plurality of rolling elements (4) of a rolling bearing (2), comprising a plurality of pockets (3) accommodating the rolling elements (4), the cage (1) comprising at least one reservoir (11) filled with a lubricant (15, 15') for delivering the lubricant (15, 15') during operation. The invention is characterized in that the reservoir (11) has at least two reservoir sections (14) in which different lubricants (15, 15') are arranged, every reservoir section (14) comprising at least one lubricant-permeable passage region (16, 27) for delivering the lubricant (15, 15').

Description

 Name of the invention

Cage for receiving a number of rolling elements of a rolling bearing and method for lubricating a rolling bearing

description

Field of the invention

The invention relates to a cage for receiving a number of rolling elements of a rolling bearing, with a number of the rolling elements receiving pockets, wherein the cage comprises at least one filled with a lubricant depot space to a discharge of the lubricant during operation. The invention further relates to a method for lubricating a rolling bearing.

A rolling bearing often comprises a so-called inner ring and an outer ring, wherein between the inner ring and the outer ring, a number of rolling elements is arranged. The rolling elements are usually arranged in a cage, so that the rolling elements are held by the cage at a defined distance from each other. During operation of such a roller bearing, the rolling elements received in the cage roll along a raceway on the inner ring and the outer ring. Lubrication by means of a lubricant is advantageous for the operation of the roller bearing. The amount of available between the rolling elements and the outer / inner ring lubricant often has a direct impact on the life and the functioning of a rolling bearing. If, for example, too little lubricant is present, this can lead to premature wear of the rolling bearing. Too much lubricant leads to an increase in the frictional resistance.

In US Pat. No. 7,114,852 B2, a cage with an internal depot space for lubricant is specified, the lubricant being conducted via channels to the rolling bodies.

OBJECT OF THE INVENTION The object of the invention is to provide a life-extending cage for a roller bearing which is as versatile as possible.

Solution of the task

The object is achieved by a cage for receiving a number of rolling elements of a rolling bearing, with a number of the rolling elements receiving pockets, wherein the cage comprises at least one filled with a lubricant depot space to a discharge of the lubricant during operation. It is provided that the depot space has at least two depot sections, in which different lubricants are arranged, and that each depot section comprises at least one lubricant-permeable passage area for dispensing the lubricant.

By providing at least two depot sections with different lubricants with different lubricating properties, it is possible, under different environmental conditions, to demand-optimized To achieve lubrication of the bearing with each adapted to the given environmental condition lubricant. Depot sections are generally understood to mean spatial areas in which the lubricants are located. The depot sections for the different lubricants here need not be separated or delimited locally. In principle, the depot sections can interlock, for example when the lubricants are immiscible lubricants which are arranged together in one space.

In particular, a targeted delivery of the lubricant from the corresponding deposit section to the area to be lubricated takes place via the respective pass-through area, for. B. to the rolling elements. This ensures a uniform lubrication between the rolling elements and, for example, the inner ring of the rolling bearing. The passage region is preferably arranged in such a way that delivery of the lubricant takes place into the pockets receiving the rolling bodies. In this case, the lubricant will, for example, deliver as a drop into the pocket such that the drop wets the surface of the rolling element in the pocket, so that the lubricant is evenly distributed along the raceway of the rolling elements by the rotation of the rolling element. Alternatively, it is also possible to orient the corresponding passage region in such a way that delivery of the lubricant takes place directly on the raceway of the rolling element. The delivery of a lubricant via the corresponding passage region then takes place, for example, from a single depot section or alternatively, for example, the delivery of a mixture of several lubricants from different depot sections is possible.

The depot space is formed for example as a cavity within the cage, wherein the individual depot sections are separated from each other, for example by walls. The respective lubricants are introduced, for example, as a lubricating oil or as a grease in the depot section. Additionally or alternatively, the depot space has a porous This material on, for example, a sponge or a porous cage section, wherein the corresponding lubricant, for example, impregnates the porous material. In the individual depot sections, in each case a lubricant in particular is arranged in the quantity intended for the service life of the rolling bearing, so that no subsequent filling of the depot sections becomes necessary.

The passage region and / or the lubricants are preferably designed such that the delivery of the respective lubricant takes place as a function of a current operating state. The lubrication with a lubricant adapted to the respective operating condition ensures the functionality and increases the service life of the rolling bearing.

The delivery of the corresponding lubricant is thereby preferably automatically, for example via a speed-dependent force, for. B. via a centrifugal force regulated. It is also possible that a regulation of the delivery of the corresponding lubricant is provided via the action of a chemical reaction, for example via a variable by a chemical reaction control element.

Advantageously, the lubricants have different viscosities. In this embodiment, for example, it is possible in a simple manner to use the different flow properties of the lubricants for automatic metering of the respectively delivered lubricant quantity. The delivery of a lubricant with a high viscosity over the corresponding passage area, for example, takes place only under the action of a magnitude larger force acting in the radial direction, for. As a centrifugal force, as the delivery of a lubricant with a lower viscosity. Thus, it is possible, for example, that the lubrication of the bearing takes place with a mixture of lubricants of different viscosities, wherein z. B. increases in a growing centrifugal force, the proportion of a highly viscous lubricant. In a preferred embodiment of the invention, the passage region is oriented in the radial direction. Accordingly, the passage region is oriented substantially in the direction of the axis of rotation about which the cage moves during operation, so that the delivery of the lubricant takes place directly into the raceway of the rolling element. As a result, in particular a minimal quantity lubrication is made possible. In addition, it is advantageously possible in this embodiment, the delivered amount of lubricant via the action of a force acting in the radial direction, for. As a centrifugal force that acts on the cage during operation to dose in a simple manner as needed. The lubricant quantity required for the current operating state is thus "automatically" metered into the raceway of the rolling element.

Conveniently, the cage comprises at least one porous portion forming the passage area, the porous portion being provided for discharging the lubricant. This embodiment is particularly simple and inexpensive to implement by the existing example of plastic or metal cage is designed to be porous overall. As a result of the effect of a centrifugal force, for example, the lubricant is then "automatically" forced out of the depot section in the radial direction through the passage area, so that the lubricant is discharged directly into the raceway of the rolling element. Preferably, the porosity varies within a passband or between different passbands to achieve control of the amount of lubricant dispensed.

In a further advantageous embodiment of the invention, the passage region comprises a channel for dispensing the lubricant. In this embodiment, it is z. B. on the choice of an opening cross-section of the channel possible, in particular to selectively influence the discharge amount of the corresponding lubricant. W

By an accurate positioning of the channel opening on the known track of the rolling element, it is also possible to realize a needs-based lubrication of the rolling element in its career. Overall, in this embodiment, the delivered amount of lubricant will be reduced to a necessary 5 maneuverable minimum.

Preferably, the channels for the depot sections have different opening cross-sections. As a result, a lubricant-specific optimal delivery quantity from the corresponding depot section is controlled via the choice of the corresponding opening cross-section.

Conveniently, the opening cross section of the channel is variable, i. it can be varied during operation. In this case, provision is made in particular for the opening cross section to change in a temperature-dependent manner, for example via a temperature-dependent expansion of the cage material surrounding the channel. This makes it possible that, for example, the opening of the channel is opened depending on the temperature, or is closed and thus a release of the lubricant takes place, or is prevented. By a suitable choice of material, the various depot sections are preferably assigned different types of channels whose respective openings change at a different temperature, so that the delivery of a lubricant from the corresponding depot section can be controlled in a temperature-dependent manner.

In an advantageous further development, the passage region comprises a closing component, wherein the closure component is provided in FIG

Depending on an environmental condition, the pass band for the

Release of the lubricant. Such a closure component is for example a plug which closes the corresponding channel and which is dissolved, for example, in the presence of an acid or a basic fluid, so that the corresponding channel is opened for the delivery of a lubricant adapted to an acidic or basic ambient condition , Alternatively, such a closure component is for example one Component that z. B. in the manufacture of the porous portion of the cage, which forms the passage area, is added and depending on the ambient conditions, for example due to chemical or physical processes changed their volume. By way of example, the component is selected such that it reduces its volume over a certain temperature interval and thus releases the pores of the passage region for the delivery of a lubricant which has been adapted to this temperature interval. Alternatively, the component responds to the ph value of the medium surrounding the cage. In a further alternative, the closure component is an active closure component, e.g. B. as a piezoelectric element formed.

Appropriately, it is additionally provided to close the closure component depending on an environmental condition, the passage area for the delivery of the lubricant. As a result, overall the functionality and the service life of the rolling elements and the entire rolling bearing is considerably increased, since the lubricant is adjusted to changing environmental conditions.

According to an expedient development, the closure component is designed such that it acts only once and in particular under certain extraordinary environmental conditions, in particular opens. As a result, depending on the environmental conditions, the suitable lubricant can be selected once. In particular, this measure serves to ensure unique emergency running properties in exceptional conditions, for example when the bearing is exposed to aggressive chemicals.

Preferably, the closure component is temperature-dependent, for which purpose a material pairing with different thermal expansion coefficients is provided. By means of a suitable combination of the material of the closure component and the material of the passage region comprising the closure component, a temperature-dependent volume Modification of the closure component of the passage region temperature-dependent for a delivery of the lubricant from the passage section associated depot automatically opened or closed. In this embodiment, it is easily possible to automatically ensure the lubrication of, for example, the rolling elements with a lubricant suitable for the given temperature.

In a preferred embodiment, the temperature-dependent controllable closure component is formed as a tube inserted into the respective channels, wherein the thermal expansion coefficients of the tube and of the material surrounding the channel are different. In this variant, for example, a plastic tube is simply inserted into a channel assigned to a depot section, so that, for example, the delivery of the lubricant located in the depot section is possible at a low temperature. When the temperature rises, the plastic tube expands faster than the opening cross-section of the channel, so that from a certain temperature limit, the tube clogged the channel, so to speak, so that the lubricant can no longer flow through the channel. In particular, it is therefore also easily possible, for example, to insert tubes with different material compositions into the respective channel of different depot sections. Depending on the different coefficients of thermal expansion of the respective tubes, the temperature-dependent expansion behavior of the tubes is predetermined in order to regulate temperature-dependent opening or closing of the channel for dispensing the corresponding lubricant.

The object is further achieved according to the invention by a method having the features of claim 15. The advantages and preferred embodiments cited with regard to the cage can also be transferred analogously to the method. With such a method, the advantage of a needs-based, in particular dependent on the ambient conditions lubricant dosage can be achieved. Of particular advantage is further that the lubricant is integrated directly in the cage, so that no complex lubricant supply is required.

Short description of the drawing

Embodiments of the invention will be explained in more detail with reference to a drawing. In each case show very schematically:

Fig. 1: in a cross section of a detail of a detail

Cage in a first embodiment,

2 shows a detail of a detail in a cross section

Cage in a second embodiment,

3 shows in a cross section a detail of a detail of a cage in a third embodiment.

Equivalent parts are provided in the figures with the same reference numerals.

Detailed description of the drawing

According to the figures, a cage 1 of a rolling bearing 2 shown in fragmentary form in the circumferential direction evenly distributed several pockets 3, in each of which a rolling element 4 is received. In the sectional representations of the figures, only one pocket 3 and a rolling element 4 is shown in each case. The cage 1 with the rolling element 4 is between an inner ring. 5 and an outer ring 6 is arranged. The rolling elements 4 protrude out of the pockets 3 and roll in operation on a respective raceway 7 of the inner ring 5 and of the outer ring 6. In use, one of the rings 5, 6 is stationary and the other ring 6, 5 rotates about a central axis of rotation of the roller bearing 2, for example in the direction of movement 10.

The cage 1 comprises a number of depot spaces 11. Two depot spaces 11 can be seen in each of the sectional representations of the figures. Each depot space 11 in turn comprises two depot sections 14. Each depot section 14 is filled with a lubricant 15, 15 '. The lubricating properties of the respective lubricants 15, 15 'differ from one another. The dimensions and the volume of the respective depot section 14 are selected so that the amount of lubricant 15, 15 'is sufficient for the service life of the rolling bearing 2.

The cage 1 is made in the embodiment of FIG. 1 from a material having porous properties, so that a delivery of the respective lubricant 15,15 'from the corresponding depot section 14 via a porous section 16 of the cage 1 takes place. The depot sections are separated from each other by an inner wall 17. During operation of the rolling bearing 2, the lubricant 15,15 'under the action of a force acting in the radial direction 19, z. B. under the action of a centrifugal force, pushed out of the respective depot section 14 and metered directly onto the raceway 7 of the rolling element 4. As a result of the movement of the rolling body 4, the lubricant 15, 15 'is then uniformly distributed on the track 7. The higher the speed of the cage 1 and, correspondingly, of the rolling element 4, the greater the radial force acting in the radial direction 19, and the greater the amount of lubricant 15, 15 'discharged from the depot section 14 onto the inner ring 5 that a speed-dependent release of lubricant takes place automatically. The porosity of the porous sections 16 differs with each other, depending on which depot section 14 of the porous section 16 is assigned. As a result, it is achieved that the different lubricants 15, 15 'are automatically metered onto the track 7 in a different mixing ratio as a function of the speed. For example, the lubricant 15 'have a higher viscosity, such that z. B. only under the action of a higher force acting in the radial direction 19, a delivery from the corresponding depot section 14 through the porous portion 16 is possible. Since the porous section 16, which is assigned to the corresponding depot section 14, has a higher porosity, ie a greater pore density, the proportion of the lubricant 15 'discharged at a higher speed increases relatively faster than the proportion of the lubricant 15 delivered For example, by selecting the lubricating properties of the lubricants 15, 15 'and the porosity of the corresponding porous section 16, it is possible to set the suitable mixing ratio of the lubricants 15, 15' for the respective speed range.

In the embodiment of FIG. 2, the lubricants 15,15 'in each case by means of a sponge 26, which is each impregnated by the corresponding lubricant 15,15', stored in the respective depot section 14. Due to this, the respective depot sections 14 of the depot space 11 do not have to be separated from one another by a partition 17, as shown in FIG.

The delivery of the respective lubricant 15,15 'from the corresponding depot section 14 via a number of channels 27, which are oriented in the radial direction 19. During operation of the rolling bearing 2, the lubricant 15,15 'is forced out of the respective depot section 14 under the action of a force acting in the radial direction 19 and metered onto the raceway 7 of the rolling element 4, whereby the lubricant 15,15' uniformly on the track 7 is distributed. The individual channels 27 have a different diameter 30 and thus a different opening cross-section. This lubricant-specific optimal release amount from the respective depot section 14 can be controlled.

In the individual depot sections 14 lubricants 15,15 'are preferably filled with different viscosities. In particular, a lubricant 15 'is provided for lubrication at a low temperature up to a limit T1. The other lubricant 15 is provided for lubrication at a higher temperature from a limit T2. Each depot section 14 is assigned in each case a channel 27, via which the respective lubricant 15, 15 'is released under the action of a force acting in the radial direction 19 from the respective depot section 14 and is metered directly onto the track 7.

In order to control a temperature-dependent release of one of the lubricants 15, 15 'from the respective depot section 14, a tube 31 made of a plastic is inserted in one of the channels 27 as a closure component in the exemplary embodiment of FIG. The figure shows the state of the cage 1, as it appears at a high operating temperature, which is above T1:

The tube 31 is inserted into the channel 27 associated with the depot section 14 with the low temperature lubricant 15 '. In the illustrated state, ie at a high operating temperature above a value T1, the inserted tube 31 closes the channel 27 and thus prevents the delivery of the corresponding lubricant 15 '. If in this case the temperature drops below a value T1, then the expansion of the tube 31 "shrinks" so that a flow of the lubricant 15 'is made possible. It is different in the channel 27, which is associated with the depot section 14 with the lubricant 15 for a lubrication at a high temperature. The diameter 30 of this channel 27 is chosen such that at a high temperature, which is above a value T2, a delivery of the corresponding lubricant 15 is possible. If in this case the temperature falls below the given limit value T2, the viscosity of the lubricant 15 increases on the one hand, with which the lubricant 15 becomes more viscous. On the other hand, the diameter 30 of the channel 27 "shrinks". Overall, therefore, the lubricant 15 can no longer flow through the channel 27. This ensures automatically adapted to the given temperature condition lubrication of the bearing 2.

List of reference numbers

1 cage

2 rolling bearings

3 bag

4 rolling elements

5 inner ring

6 outer ring

7 career

10 direction of movement

11 depot room

14 depot section

15.15 'lubricant

16 porous section

17 partition

19 radial direction

26 sponge

27 channel

30 diameters

31 tubes

Claims

claims A cage (1) for receiving a number of rolling elements (4) of a roller bearing (2), comprising a number of pockets (3) accommodating the rolling bodies (4), the cage (1) being provided with at least one lubricant (15, 15). 15 ') filled depot space (11) for delivery of the lubricant (15,15') during operation, characterized in that the depot space (11) has at least two depot sections (14) in which different lubricants (15,15 ') and that each depot section (14) comprises at least one lubricant-permeable passage region (16, 27) for dispensing the lubricant (15, 15 '). 2. Cage (1) according to claim 1, characterized in that the passage region (16, 27) and / or the lubricants (15,15 ') are formed such that the delivery of the respective lubricant (15,15') in dependence from a current operating state. 3. cage (1) according to any one of the preceding claims, characterized the lubricants (15, 15 ') have different viscosities. 4. Cage (1) according to one of the preceding claims, characterized in that the passage region (16, 27) in the radial direction (19) is oriented. 5. cage (1) according to any one of the preceding claims, characterized in that it comprises at least one porous portion (16) which forms the passage area, wherein the porous portion (16) for discharging the Lubricant (15,15 ') is provided. 6. Cage (1) according to one of the preceding claims, characterized in that the passage region comprises a channel (27) for discharging the lubricant (15,15 '). 7. Cage (1) according to claim 6, characterized in that the channels (27) for the depot sections (14) have different opening cross-sections. 8. Cage (1) according to claim 7, characterized in that the opening cross-section of the channel (27) is variable. 9. Cage (1) according to any one of the preceding claims, characterized in that the passage region (16,27) comprises a closure component (31), wherein the closure component (31) is provided, depending on an environmental condition, the passage region (16,27) to open the lubricant (15,15 '). 10. Cage (1) according to claim 9, characterized in that the closure component (31) is provided, depending on an environmental condition, the passage area (16,27) for the delivery of the lubricant (15,15 ') shut down. 11. Cage (1) according to any one of claims 9 to 10, characterized in that the closure component (31) acts only once in response to an extraordinary environmental condition. 12. Cage (1) according to any one of claims 9 to 11, characterized in that the closure component (31) acts temperature-dependent, for which purpose a material pairing with different coefficients of thermal expansion is provided. 13. Cage (1) according to claim 12, characterized in that for the formation of the temperature-dependent closure component in the channel (27) a tube (31) is inserted, wherein the thermal expansion coefficient of the tube (31) and surrounding the channel (27) Materials are different. 14. A method for lubricating a rolling bearing (2) having a cage (1) in which a number of rolling elements (4) in pockets (3) are accommodated, wherein for lubricating the rolling bearing (2)) from a with a lubricant (15 , 15 ') filled depot space (11) of the cage (1) in the operation lubricating substance (15,15') is characterized in that in the cage at least two different lubricants (15,15 ') are stocked and that the roller bearing (2) is lubricated depending on demand, at least with one of the two lubricants.