Axial rolling bearing unit with rolling elements arranged between annular axial bearing discs and an internal lubricant guide

Abstract

Axial rolling bearing unit with rolling elements (4) arranged between two annular axial bearing discs (1, 2), which are guided by a bearing cage (3) formed from a sheet metal material, which has an inner and outer radially extending edge rim (5, 6) for radially guiding the rolling elements (4), wherein the two inner and outer radial axially directed edge rims (5, 6) extend from one of the two axial bearing discs (1) to the other axial bearing disc (2), wherein the one inner radial edge rim (5) is designed as a double rim with an end bend (7) in the opposite direction and the outer radial edge rim (6) is provided with lubricant openings (10) arranged spaced apart from one another in the circumferential direction, characterized in that - the edge rims (5, 6) are each designed with a curved distal end section (8, 9) as positive-locking holding means of the bearing cage (3) for each associated axial bearing disc; - the axial bearing discs (1, 2) are designed as identical parts and are provided with inner and outer radial edge shoulders (11, 12) for positive engagement with the associated curved distal end sections (8, 9), - the distal end sections (8, 9) are bent at right angles in the direction of the bearing interior and occupy a free space created by the edge shoulders (11, 12), - the distal end portion (8) is formed on the end bend (7) of the inner radial edge rim (5), - the inner radial edge rim (5) forms a lubricant inlet in the area between the bend (7) and the axial bearing disc (2) adjacent to it, the gap width of which can be defined, the lubricant openings (10) being arranged at equidistant intervals from one another along the outer radial edge rim (6) and in alignment with the longitudinal axes of the rolling elements (4).

Description

[0001] The present invention relates to an axial rolling bearing unit with rolling elements, preferably needle or roller elements, arranged between two annular axial bearing disks, which are guided by means of a bearing cage formed from a sheet metal material, which has an inner and outer radial edge rim extending in the axial direction for radial guidance of the rolling elements, wherein the inner radial edge rim is designed as a double rim with an end bend in the opposite direction and the outer radial edge rim is provided with lubricant openings arranged spaced apart from one another in the circumferential direction.

[0002] The field of application of the present invention extends primarily to automotive applications in which, for example, a shaft equipped with helical gears is subjected to an axial force, which must be absorbed by a suitable axial bearing relative to a transmission housing or the like. The solution according to the invention is particularly dedicated to the largely metal-forming production of the bearing components, in particular the bearing cage and the axial bearing washers. State of the art

[0003] From DE 20 57 620 A it is generally known to provide the outboard of a bearing cage of axial bearing units with radial openings to improve the lubricant flow.

[0004] EP 1 744 070 A2 discloses an axial rolling bearing unit of the type of interest here, whose cage-guided rolling elements are arranged between two axial bearing discs with a Z-profile. The axially outwardly projecting inner collars of the axial bearing discs correspond to an annular groove of a transmission shaft or the like to position the axial rolling bearing unit. The axially inwardly projecting outer collars of the axial bearing discs, in contrast, come into contact with one another, thus creating the greatest possible encapsulation of the axial rolling bearing unit, preventing lubricant penetration.

[0005] This previously known technical solution creates a largely closed, encapsulated bearing, which prevents undefined passage of lubricant through the interior of the bearing.

[0006] In applications with higher bearing loads, however, a continuous flow of lubricant must be ensured to prevent overheating of the bearing point and bearing wear.

[0007] According to the generally known prior art, axial rolling bearing units with angled thrust bearing washers encapsulating the bearing interior are usually supplied with the required amount of lubricant through oil grooves or the like incorporated therein. This requires a corresponding design modification of the thrust bearing washers.

[0008] JP 2006–22 846 A discloses various designs of double rims.

[0009] DE 10 2008 018 291 A1 and JP 2015–31 390 A disclose an axial rolling bearing unit in which the inner radial rim of the bearing cage is designed as a double rim, and the outer rim is provided with lubricant openings arranged circumferentially relative to one another for lubrication purposes. The two axial bearing discs are designed differently, and at least one is designed with an rim extending in the axial direction.

[0010] In DE 196 18 216 A1 and JP 2016–128 713 A, circular lubricant penetrations are provided inside the bearing cage. These are axially aligned.

[0011] US 10 941 811 B1 and JP 2008– 151 216 A disclose snap lugs formed on the axial bearing shells, which engage in the bearing cage and thus ensure the cohesion of the components of the axial bearing unit in the unassembled state.

[0012] As an alternative, JP 2014–5 919 A ​​shows the design of the retaining elements on the bearing cage, which engage in correspondingly designed grooves in the axial bearing washers. The two axial bearing washers are designed differently.

[0013] It is the object of the present invention to further improve an axial rolling bearing unit with annular, non-angled axial bearing discs and an inner and outer radial edge of the bearing cage extending in the axial direction in such a way that sufficient flow lubrication is made possible with simple technical means at higher bearing loads. Disclosure of the invention

[0014] The object is achieved by an axial rolling bearing unit according to claim 1. The following dependent claims reflect advantageous developments of the invention.

[0015] In an axial rolling bearing unit with rolling elements arranged between two annular axial bearing discs, which are guided by a bearing cage formed from sheet metal, each having an axially extending rim on the inner and outer radial sides, the inner radial rim is designed as a double rim, which is provided with an end bend in the opposite direction, and the other, outer radial rim is provided with lubricant passages spaced apart from one another in the circumferential direction and also with an end bend. The end bends of the two rims engage with edge shoulders on the similarly designed axial bearing discs.

[0016] The advantage of the inventive solution lies in the fact that the inner-radially doubled rim forms a lubricant inlet with a defined gap width in the area between the bend and the adjacent axial bearing disk. Due to the centrifugal forces occurring during operation, the lubricant is drawn into the bearing interior and thus to the rolling elements. To ensure further lubricant flow, the radially outer rim of the bearing cage is provided with lubricant openings arranged equidistantly and in alignment with the rolling element axis. These lubricant openings are thus located directly next to the rolling elements and ensure direct lubricant drainage to the outside.Since the axial bearing washers of the axial rolling bearing unit according to the invention are flat, they do not require any passage geometries for internal lubricant guidance, but instead direct the lubricant radially outward within the bearing. In other words, in the solution according to the invention, the bearing cage, instead of the axial bearing washers, takes over the formation of the oil inlet and outlet geometries.

[0017] Not every lubricant hole needs to correspond to the longitudinal axis of each rolling element. However, the aligned arrangement allows for optimal exit of the rolling elements surrounded by lubricant. In this regard, it is sufficient if the roller axes of the rolling elements, located on the pitch circle, are aligned such that they penetrate the area of ​​the lubrication holes.

[0018] In the solution according to the invention, the two rims, each with a curved distal end section, advantageously serve as positive-locking holding means of the bearing cage for each associated axial bearing disk. In functional integration, the bearing cage according to the invention, in addition to its guiding function for the rolling elements and an internal lubricant guide, is also intended to captively hold the axial rolling bearing unit together. In particular, the free end opposite the end bend of the preferably inner radial rim can be used to enclose the adjacent axial bearing disk. Similarly, the distal end section of the outer radial rim encompasses the other axial bearing disk, creating a positive-locking connection between the components.

[0019] To create the component connection, the axial bearing washers are provided with inner and outer radial edge shoulders, which serve to ensure a positive engagement with the corresponding distal end section of the bearing cage. The distal end sections are bent approximately at a right angle toward the inside of the bearing to occupy the free space created by the edge shoulders, thus creating outwardly flat end surfaces of the axial bearing unit.

[0020] According to the invention, the two axial bearing discs are designed as identical parts, i.e. they are provided with edge shoulders or edge bevels of the type explained above on both the inner and outer radial sides in order to minimize the number of individual parts required for the axial rolling bearing unit according to the invention.

[0021] Preferably, the lubricant apertures should each have a circular cross-section that is smaller than the diameter of the rolling elements. This creates a sufficient outlet cross-section for the lubricant, while also preventing the peripheral rim provided with the lubricant apertures from being weakened to such an extent that it could lose its dimensional stability, even under high bearing loads. The lubricant apertures can also have a slot-shaped, polygonal, oval, or similar cross-section, as well as combinations of these, if this allows sufficiently large outlet cross-sections to be created depending on the application.

[0022] Alternatively, the axial bearing washers can also be provided with inner and outer radial edge chamfers, for example, between 40° and 50°, against which the distal end sections of the bearing cage, which are bent inward in approximately the same way, rest. The smaller bending angle avoids the risk of material cracking at the bending point.

[0023] To achieve a less complex manufacturing process, it is proposed that the annular axial bearing washers be manufactured as stamped and embossed parts from sheet metal. Similarly, the bearing cage is preferably manufactured as a stamped and bent part, with its axially extending rims being created in a single deep-drawing step.

[0024] According to a preferred embodiment, the bearing cage manufactured in this way from sheet metal material has bearing webs spaced apart from one another in the circumferential direction, which guide a rolling element in pairs in the circumferential direction and are each designed in the form of a so-called sigma profile. The generally known sigma profile starts from an axial side of the bearing cage with initially short, mutually facing radial sections, followed by mutually facing inclined flank sections that culminate in a radially extending crest section, the profile of which roughly resembles the capital Greek letter sigma. This provides the prerequisite for the two inner and outer radially directed edge ribs to extend from one of the two bearing disks to the other bearing disk, which in turn is the prerequisite for forming the lubricant guide according to the invention. Description based on the drawing

[0025] Further measures improving the invention are described in more detail below, together with the description of a preferred embodiment of the invention, with reference to the figures. It shows: Fig. 1 a partial longitudinal section through an axial rolling bearing unit, and Fig. 2 a perspective sectional view of the axial rolling bearing unit according to Fig. 1, but without axial bearing washers.

[0026] According to Fig. 1, the axial rolling bearing unit consists of rolling elements 4 arranged between two annular axial bearing discs 1 and 2 and guided by a bearing cage 3. The rolling elements 4 are designed here as roller or needle bodies.

[0027] The bearing cage 3, formed from sheet metal, has an inner radial rim 5 extending in the axial direction and an outer radial rim 6 extending in the axial direction for radial guidance of the rolling elements 4. The inner radial rim 5 is designed as a double rim and is provided with a bent end 7 in the opposite direction. In contrast, the other rim 6 has lubricant openings 10 arranged at a distance from one another in the circumferential direction.

[0028] The two edge rims 5 and 6, together with the respective distal end sections 8 and 9, serve as a positive-locking holding means of the bearing cage 3 for an associated axial bearing disk 1 and 2, respectively, so that a self-contained structural unit is thereby produced.

[0029] The axial bearing discs 1 and 2 are provided with inner and outer radial edge shoulders 11 and 12, respectively, which serve for the positive interaction with the associated right-angled bent distal end sections 8 and 9, respectively.

[0030] For internal bearing lubricant guidance, an oil inlet gap, marked here by an arrow, is formed between the bend 7 of the double-ribbed inner radial rim 5 and the adjacent axial bearing disk 2. An oil outlet, also marked by an arrow, is formed by the lubricant openings 10 of the outer radial rim 6.

[0031] According to Fig.2, the lubricant apertures 10 of the outer radial rim 6 are arranged at equidistant intervals from one another and aligned with the longitudinal axes of each rolling element 4. The lubricant apertures 10 have a circular cross-section whose diameter is smaller than the diameter of the rolling elements 4 located behind them in the inner direction of the bearing.

[0032] The bearing cage 3, formed from sheet metal, has circumferentially spaced bearing webs 13, whose profile contours are indicated by the dashed line. Due to their sigma profile, the adjacent bearing webs 13 form a frame for each of the rolling elements 4. List of reference symbols 1 first axial bearing disc 2 second axial bearing disc 3 bearing cage 4 rolling elements 5 inner radial edge rim 6 outer radial edge rim 7 Bend 8 first distal end section 9 second distal end section 10 Lubricant breakthrough 11 inner radial edge shoulder 12 outer radial edge shoulder 13 Bearing bridge

Claims

[1] Axial rolling bearing unit with rolling elements (4) arranged between two annular axial bearing discs (1, 2), which are guided by a bearing cage (3) formed from a sheet metal material, which has an inner and outer radially extending edge rim (5, 6) for radially guiding the rolling elements (4), wherein the two inner and outer radial axially directed edge rims (5, 6) extend from one of the two axial bearing discs (1) to the other axial bearing disc (2), wherein one inner radial edge rim (5) is designed as a double rim with an end bend (7) in the opposite direction and the outer radial edge rim (6) is provided with lubricant openings (10) arranged spaced apart from one another in the circumferential direction, characterized by , that - the edge rims (5, 6) are each designed with a curved distal end section (8, 9) as positive-locking holding means of the bearing cage (3) for each associated axial bearing disc; - the axial bearing discs (1, 2) are designed as identical parts and are provided with inner and outer radial edge shoulders (11, 12) for positive engagement with the associated curved distal end sections (8, 9), - the distal end sections (8, 9) are bent at right angles in the direction of the bearing interior and occupy a free space created by the edge shoulders (11, 12), - the distal end portion (8) is formed on the end bend (7) of the inner radial edge rim (5), - the inner radial edge rim (5) forms a lubricant inlet in the area between the bend (7) and the axial bearing disc (2) adjacent to it, the gap width of which can be defined, the lubricant openings (10) being arranged at equidistant intervals from one another along the outer radial edge rim (6) and in alignment with the longitudinal axes of the rolling elements (4). [2] Axial rolling bearing unit according to claim 1, characterized by that the lubricant openings (10) each have a circular cross-section which is smaller than the diameter of the rolling elements (4). [3] Axial rolling bearing unit according to claim 1, characterized by that the lubricant openings (10) each have a slot-shaped, polygonal or oval cross-section. [4] Axial rolling bearing unit according to one of the preceding claims, characterized bythat the annular axial bearing discs (1, 2) are also produced as stamped and embossed parts from a sheet material by forming. [5] Axial rolling bearing unit according to one of the preceding claims, characterized by that the bearing cage (3) has bearing webs (13) which are each designed in the form of a sigma profile. [6] Axial rolling bearing unit according to one of the preceding claims, characterized by that for the internal bearing lubricant guidance between the bend (7) of the inner radial edge rim (5) and the axial bearing disc (2) adjacent to it, an oil inlet gap is formed, from which the lubricant flows centrifugally driven in the radial direction past the rolling elements (4) in order to exit again from the lubricant openings (10) of the outer radial edge rim (6).

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