WO2021148502A1

WO2021148502A1 - Spacer elements and large rolling bearing comprising such spacer elements

Info

Publication number: WO2021148502A1
Application number: PCT/EP2021/051268
Authority: WO
Inventors: Jens RAPPOLD; Yevgenij SHARYPKIN
Original assignee: thyssenkrupp rothe erde Germany GmbH; Thyssenkrupp Ag
Priority date: 2020-01-24
Filing date: 2021-01-21
Publication date: 2021-07-29
Also published as: DE102020200865A1

Abstract

The invention relates to a spacer element for spacing two balls of a row of balls in a slewing bearing, comprising ball receiving areas (5) which are adapted to the shape of the balls on both sides, point in opposite directions, and are arranged at a distance from each other, wherein the ball receiving areas (5) are equipped with vanes (6) which are distributed over the circumference when viewed from the end face and protrude in a star-shaped manner, said vanes comprising a vane inner face (7), which is adapted to the shape of the balls and which further develops the ball receiving areas (5), and a vane casing (8) pointing away from the ball receiving area (5). The invention also relates to a ball bearing, the balls of which are mutually spaced by such spacers.

Description

description

Spacer bodies and large roller bearings with such spacer bodies

The invention relates to spacer bodies for spacing two balls of a row of balls apart in a rotary ball joint, comprising ball receptacles which are adapted to the ball shape on both sides and point in opposite directions and are spaced apart from one another. The invention also relates to a ball bearing with two mutually rotatable bearing rings and with at least one row of balls that can roll between the bearing rings.

Such spacer bodies are known, for example, from DE 26 10 707 C2.

Spacer bodies are used in large roller bearings - also referred to as spacers - in order to space the roller body balls, in short: balls, arranged between the bearing rings, and to hold them in the bearing rings to reduce the wear and tear on the balls. For this purpose, the spacer bodies arranged between the balls form a rotary ball joint in that two balls are inserted into the two opposing rolling body receptacles, in short: receptacles, of the spacer body. To reduce bearing friction and increase the service life of the bearing, it is lubricated with lubricants, for example grease or oil. For this purpose, lubricant pockets, which are arranged in the roller body receptacle of the spacer body, are used. For efficient lubrication, it is particularly important not only to ensure that the lubricant is collected in the lubricant pockets, but also that there is a sufficient amount of lubricant exchange between the balls and the raceway of the bearing rings. In the case of lubricant pockets known from the prior art, there is a marked tendency towards pure lubricant accumulation in the lubricant pockets and consequently insufficient distribution of lubricant in the running system. In addition to ensuring a sufficient exchange of lubricant, a further requirement for a spacer body to be used in a large roller bearing is that it is designed to be as optimized as possible in terms of mass, load and resource consumption. The mass optimization is simply based on the fact that, due to the large number of spacers used, a lightweight construction of the spacers not only reduces the weight of the large roller bearings, but also their friction. In addition, there is a requirement for the spacer body that it is designed in a load-optimized manner, that is to say that only those parts of the spacer body are designed with a high material thickness that also experience a strong mechanical load. Resource consumption optimization is relevant simply for reasons of cost efficiency.

Spacer bodies for use in large roller bearings are usually made of plastic and manufactured using a plastic injection molding process. There is a risk of voids, that is, the formation of cavities in the walls of the spacer body as a result of inhomogeneous wall thicknesses of the plastic component. Such voids have proven to be problematic for the dimensional stability of the spacer body. As soon as a spacer body installed in the large roller bearing loses its dimensional stability, for example breaks, this makes expensive repairs necessary in addition to the costs associated with taking the bearing out of operation in order not to risk irreversible damage to the raceway or the balls. In order to avoid the formation of voids, a spacer body must therefore be designed so that its wall thicknesses are as homogeneous as possible.

No spacer bodies are currently known from the prior art which adequately meet the above-mentioned requirements.

The invention is therefore based on the object of providing a spacer body which overcomes the disadvantages mentioned above, in particular enables an improved exchange of lubricant, which is mass, load and Is designed to optimize the use of resources and in which the susceptibility to form instabilities is minimized.

This object is achieved according to the invention by a generic spacer body of the type mentioned at the outset, in which, viewed from the end face, star-shaped projecting wings are formed on the spherical receptacles, with a wing inner side adapted to the spherical shape that further develops the spherical receptacles and a wing jacket pointing away from the ball receptacle.

Such a spacer body comprises two ball seats pointing in opposite directions, each ball seat having a dome-like shape that is adapted to the balls and is suitable for receiving a ball. The two ball receptacles are spaced from one another, so that the balls inserted in a bearing ring of a ball bearing, in particular a large roller bearing, do not touch one another. This reduces the wear on the balls and thus increases both the service life and the maintenance intervals of the ball or large roller bearing.

On a spacer body according to the invention, when viewed from the front, star-shaped projecting wings are formed on the spherical receptacles, distributed circumferentially. These wings have both a wing inner side designed in accordance with the spherical shape and further developing the ball receptacles and a wing jacket pointing away from the ball receptacle.

It is advantageous in the spacer body according to the invention that the wings are arranged in a star shape; therefore there is a distance between the individual wings. Compared to spacer bodies with a continuous outer contour, this allows not only a significant saving in weight, but also better lubrication of the balls or the bearing ring raceway, as the spaced-apart vanes result in better lubricant distribution on the balls and / or lubricant in the raceway. At the same time, the wings effectively prevent the spacer body from tilting in the track.

In the preferred case that lubricant pockets for receiving lubricant are integrated into the ball receptacles, the wings of the spacer body according to the invention cause a lubricating film to be formed at the interface between wing insides and ball, within which - driven by the rotation of the balls relative to the lubricant pockets - a flow of lubricant is maintained, by means of which a continuous exchange of lubricant between the lubricant pockets and the area of the balls coming into contact with the vanes is achieved.

In a preferred embodiment, the wings of the spacer body according to the invention run in the manner of a web on the outside of the spacer body and each open into a wing which is molded onto the opposite ball seat. Due to the spacing between the wings and the mutual support of the wings among one another in pairs, a spacer body that is particularly optimized in terms of mass, load and resource consumption is provided.

The wings preferably extend essentially in an axial direction which is defined by the center points of the two ball receptacles. Other designs of the wings are also possible, in particular those that enable the spacer body to rotate about its own axis. This can be achieved, for example, by extending the wings in a helical or oblique manner. This increases the service life of the roller bearing, since the formation of a track in the raceway of the bearing rings is effectively avoided by distributing any local concentrated mechanical action or friction of the spacer bodies on the raceway over the entire raceway due to the rotation of the spacer body. The wing jacket advantageously has a V-shaped notch. This enables use on smaller running circle diameters without the intermediate pieces colliding with the inner track of the ball bearing.

Particularly preferably, the vane casing is geometrically adapted to the raceway of a large roller bearing. This counteracts undesired tilting of the spacer body in the raceway of the bearing rings in a particularly effective manner.

In a preferred embodiment, the spacer body according to the invention is made of plastic. Such production takes place regularly by means of a plastic injection molding process using an injection molding tool. In the case of the spacer body according to the invention, a cored structure is realized by the provision of the wings according to the invention in comparison with the prior art in which a simple plastic dome is regularly used. This coring leads to more even cooling during the plastic injection molding process. Due to the more homogeneous wall thicknesses of the spacer body according to the invention, the risk of undesired formation of cavities, which negatively affects the dimensional stability, is significantly reduced.

An embodiment of the invention is particularly advantageous in which the spherical receptacles have a recess in the area of their bottom to provide a spherical zone-shaped contact surface adapted to the spherical shape. The recess together with the spherical zone-shaped contact surface produced in this way provides a structure that is lowered within the spherical shape. As a result, point contact between the bottom of the ball receptacle and the ball is effectively avoided, in that the ball rests linearly on the spherical zone-shaped contact surface when the load is low and flat under load. The level of stress in the contact area is significantly reduced by the surface contact. In addition, the provision of such a spherical zone-shaped contact surface creates the possibility of a slight geometric variation of the spherical zone-shaped contact surface, for example the Radius to be able to optimally distribute the occurring mechanical stress in the component, which has a positive effect on the service life of the spacer body. For the preferred case that the spacer body according to the invention is made of plastic, the lowered structure provides the advantageous option of placing the injection point centrally in the cavity of the injection molding tool, which further reduces the risk of blowholes.

The line contact at low loads preferably occurs at an edge of the sunken structure. This edge is particularly preferably designed with a bevel which has a selectable angle to the spherical zone-shaped contact surface. The distribution of the stresses in the spacer body can be adjusted via the angle of the bevel, thus further reducing the material requirement.

In a preferred embodiment of the spacer body according to the invention, the individual wings are arranged in wing groups, the distance between the wing groups being greater than the distance between the wings within a wing group. The formation of such wing groups pursues the goal of reducing the complexity of the injection molding tool and that of the manufacturing process, especially in the case of the production of the spacer body from plastic. This is achieved in that the spacer body with wing groups can be demolded on the basis of rectilinear movements.

The wings are preferably designed as plates protruding in the shape of a star, which extend axially with respect to an axis of the spacer body defined by the spherical receptacles. A simple, plate-shaped geometry of the wings combines the advantages of a reliable support of the spacer body on the boundaries of the track system with a simplified demoldability in the manufacturing process.

The spacer body preferably has at least 8 star-shaped projecting wings. In particular, when the wings are plate-shaped, there is a higher number of wings, for example in the range of 8 to 16 wings, in particular 12 wings, advantageous. As a result, stable contact between the spacer body and the walls of the track system can be achieved.

In a preferred embodiment, the wings are at least partially connected by at least one transverse web, which is formed on the outside of the ball seats. The transverse web runs transversely to the direction in which the wings extend. The transverse web provides an additional support effect for the wings, which in particular reduces plastic deformations of the wings in the area of the outer diameter of the spacer body. As a result, the spacer body can absorb significantly greater circumferential stresses. The result is greater resistance to material deformation, both radially and axially. The support effect of the transverse web increases the compressive strength of the spacer body, to be precise disproportionately to the additional use of material compared to a spacer body that is not reinforced by a transverse web.

At the same time, the transverse web advantageously increases the flow resistance of the spacer body compared to the lubricant provided in the track system, with only minimal use of material. It may be desirable to increase the flow resistance of the spacer body so that the spacer body is pushed forward not only by contact with the balls of the rolling bearing, but also by the lubricant transported by these in the raceway system. As a result, the loads occurring on the spacer body are reduced.

The transverse web is preferably arranged centrally in the area of a plane of symmetry of the spacer body which extends transversely to the axis of the spacer body.

The transverse web is preferably designed to be circumferential and connects all the wings of the spacer body to one another. Through a circumferential crossbar Circumferential stresses are removed particularly effectively and the flow resistance is significantly increased.

In preferred embodiments, the transverse web terminates flush with the wing shells of the wings connected by the transverse web, simulating their outer contour. In this case, the transverse web supports the wings up to their outer circumference, as a result of which a spacer body with particularly high dimensional stability and particularly high flow resistance is created. At the same time, the outer contour of the wing, which is simulated by the transverse web, forms a further support surface in relation to the track system, so that the stability of the spacer body in the track system is improved.

The transverse web can have a web width in the range of 3% to 30% of the axial extent of the spacer body on the radially outer side. With web widths of just a few percent of the spacer body, considerable advantages in terms of dimensional stability and flow resistance can be achieved. With increasing web width, the dimensional stability of the spacer body increases further.

It can be provided that the web width of the transverse web increases in the radial direction from the inside to the outside. As a result, the use of material can be optimized with high web widths of the crossbar, since a wider crossbar stabilizes the wings particularly effectively at their outer diameter.

The present invention also relates to a large roller bearing with two mutually rotatable bearing rings and a multiplicity of balls installed between the bearing rings, the balls being held at a distance in the large roller bearing by the above-described spacer bodies according to the invention. The bearing rings can also be constructed in several parts from several partial rings and / or ring segments fixed to one another. Advantageous further developments result from the subclaims, the following description and the figures.

The invention is described below on the basis of exemplary embodiments with reference to the accompanying figures. Show it:

1: A perspective illustration of a spacer body known from the prior art,

FIG. 2: a side view of the spacer body shown in FIG. 1 in a partially sectioned illustration.

3: a perspective illustration of a spacer body according to the invention,

FIG. 4: a side view of the spacer body according to the invention shown in FIG. 3 in a partially sectioned illustration;

FIGS. 5A and 5B show, in a perspective illustration and a side view, a second exemplary embodiment of the invention

Spacer body with a circumferential transverse web connecting the wings and

FIGS. 6A and 6B show, in a partially sectioned illustration and a side view, a third exemplary embodiment of the invention

Spacer body with a circumferential transverse web connecting the wings with a web width increasing radially outward.

In the various figures, the same parts are always provided with the same reference numerals and are therefore usually only named or mentioned once. 1 and 2 show a spacer body known from the prior art. Such a previously known spacer body has two spaced apart ball receptacles 1 into which the balls of a ball bearing are inserted in order to space the two balls from one another in order to reduce the wear of the balls. The distance between the two balls is given by the distance between the two contact points 2 in the area of the bottoms 3 of the ball receptacles 1 (see FIG. 2). In order to reduce the bearing friction and increase the service life of the bearing, the bearing is lubricated by providing lubricant pockets 4, which are arranged in the ball seat 1 of the spacer body, with the tendency of pure lubricant to accumulate in the lubricant pockets and thus of insufficient distribution of lubricant. The outer contour of such a previously known, typically made of plastic, spacer body is designed to be closed. This promotes the risk of cavities forming in the walls of the spacer body as a result of inhomogeneous wall thicknesses of the plastic component. This is associated with a not inconsiderable impairment of the required dimensional stability. Therefore, such a spacer body is made massive in order to counter the increased risk of form instability. This results in a high consumption of resources and mass, which increases both the production costs and the frictional resistance caused by such a spacer body.

In contrast to the previously known spacer body, the spacer body according to the invention, shown in a perspective view in Fig. 3, does not have a closed outer contour, but rather a plurality of wings 6 projecting circumferentially in a star shape when viewed from the end face of the spherical receptacles 5 and with wing inner sides adapted to the spherical shape and further developing the spherical receptacles 5 7 and a wing jacket 8 pointing away from the ball receptacle 5. This configuration allows both a low consumption of resources and mass as well as an extremely high degree of dimensional stability. In particular for the production of the spacer bodies by means of a plastic injection molding process, the configuration according to the invention with wings 6 protruding in a star shape from the ball seats 5 has an advantageously cored design, which promotes the formation of homogeneous wall thicknesses and effectively reduces the risk of voids and the associated form instability.

Furthermore, the wings 6 of such a spacer body enable the lubrication of the balls or the raceway to be improved in that the spaced apart wings 6 contribute to a better lubricant distribution of the lubricants located on the balls or the raceway.

The case shown in FIGS. 3 and 4 is particularly advantageous in which lubricant pockets 9 for receiving lubricants are integrated into the ball receptacles 5. Then, in interaction with the wings 6 of the spacer body according to the invention, a lubricating film is formed at the interface between the wing insides 7 and the ball, within which a lubricant flow is generated, through which an effective exchange of lubricant between the lubricant pockets 9 and the area that comes into contact with the wings 6 Balls is reached. As a result, the transportation of lubricant collected in the lubricant pockets 9 is promoted to the outside. This significantly reduces the friction of the entire ball bearing.

The spacer body shown in FIGS. 3 and 4 is also characterized in that each wing 6 opens into a wing 6 in the manner of a web on the outside of the spacer body, which is formed in the circumferential direction at a corresponding point on the opposite ball seat 5. This creates a special level of mass, load and

Resource consumption optimization achieved.

In addition, the wing jacket of such a spacer body has a V-shaped notch 10. This makes a bet on smaller ones Running circle diameters made possible without the spacers colliding with the raceway.

An excellent load optimization of the spacer body according to the invention shown in FIGS. 3 and 4 is achieved in that the spherical receptacles 5 have a recess in the area of their bottom 11 to provide a spherical zone-shaped contact surface 12 adapted to the spherical shape. This provides a structure that is lowered within the ball seat 5, effectively avoiding point contact between the bottom 11 of the ball seat 5 and the ball, in that the ball rests linearly on the ball zone-shaped contact surface 12 when the load is low and flat under load. As a result, the load level in the contact area between the ball seat 5 and the ball is also significantly reduced. The recess can be designed, for example, in the shape of a spherical disk.

The described spacer body according to the invention also has an arrangement of the individual wings 6 in wing groups 13, the distance between the wing groups 13 from one another being greater than the distance between the wings 6 within a wing group 13. The wings 6 of each wing group 13 are preferably arranged essentially parallel to one another. This simplifies the complexity of the injection molding tool to be used and the production process, in that the spacer body with wing groups 13 can be demolded on the basis of movements directed in a straight line.

As shown in FIGS. 3 and 4, the wings 6 can be designed as star-shaped protruding plates which extend axially with respect to an axis of the spacer body defined by the ball receptacles, and in particular their center points.

A second exemplary embodiment of a spacer body according to the invention is shown in FIGS. 5A and 5B. In the spacer body of the second embodiment, the wings 6 are connected by a transverse web 14, the is formed on the outside of the ball seats 5. The transverse web 14 is formed circumferentially and connects all the wings 6 of the spacer body with one another. However, embodiments in which only selected wings are connected by one or more transverse webs are also conceivable. For example, each wing 6 of a wing group 13 could be connected to a transverse web that is interrupted in the area between the wing groups 13.

As can be seen in particular in FIG. 5B, the transverse web 14 preferably ends flush with the wing casings 8 of the wings 6 connected by the transverse web 14, simulating their outer contour. In particular, a V-shaped notch in the wings 6 can be reproduced as an outer contour by the transverse web 14. The transverse web 14 thus forms a high flow resistance without protruding beyond the outer contour of the wing. The advantage of the V-shaped notch in the case of narrow radii of curvature of the raceway system is retained even when a flush crosspiece is used.

The transverse web 14 has, radially on the outside, a web width 15 in the range from 3% to 30% of the axial extent of the spacer body. In the exemplary embodiment according to FIGS. 5A and 5B, a comparatively narrow transverse web of approximately 5% of the axial extent of the spacer body is provided.

Otherwise, the description of the first exemplary embodiment applies correspondingly to the second exemplary embodiment.

The third exemplary embodiment shown in FIGS. 6A and 6B differs from the second exemplary embodiment according to FIGS. 5A and 5B in the design of the transverse web 14. The transverse web 14 of the third exemplary embodiment has a larger web width 15 radially on the outside, for example about 25% of the axial extent of the spacer body. In order to increase the dimensional stability of the spacer body as much as possible with as little material as possible, the web width 15 of the transverse web 14 increases in the radial direction from the inside to the outside, as can be seen in particular in the sectional view according to FIG. 6A. The web width 15 and in particular its increase in the radial direction can be optimized to the effect that the required compressive strength of the spacer body is achieved with the least possible use of material.

For example, by increasing the maximum web width 15, the spacer body can withstand a higher compressive force from the balls without being pierced. At the same time, the savings in material compared to a non-reinforced spacer body are less due to the increase in the web width 15, which leads to a reduced saving in resources and costs. For this reason, the maximum web width 15 should be increased to such an extent that the spacer body is not pierced by the compressive force to be withstood by the requirements of the large roller bearing application (optimum).

Otherwise, the explanations relating to the first and second exemplary embodiments apply accordingly.

List of reference symbols

1 ball seat (state of the art)

2 contact points (state of the art)

3 floor (state of the art)

4 lubricant pocket (state of the art)

5 ball seats

6 wings

7 wing inside

8 wing mantle

9 lubricant pockets

10 V-shaped notch

11 floor

12 spherical zone-shaped contact surfaces

13 wing group

14 crossbar

15 bar width

A axis of the spacer body

Claims

1. Spacer body for spacing two balls of a row of balls in a spherical rotary joint, comprising ball mountings (5) that are adapted to the spherical shape on both sides, pointing in opposite directions and spaced apart from one another, characterized in that, viewed from the front, circumferentially distributed, star-shaped projecting wings on the ball mounts (5) (6) are integrally formed with a wing inside (7) adapted to the spherical shape and further developing the ball seats (5) and with a wing jacket (8) pointing away from the ball seat (5).

2. Spacer body according to claim 1, characterized in that the wings (6) extend in the manner of a web on the outside of the spacer body and each open into a wing (6) which is integrally formed on the opposite ball seat (5).

3. Spacer body according to claim 2, characterized in that the wing jacket has a V-shaped notch (10).

4. Spacer body according to one of claims 1 to 3, characterized in that in the ball seats (5) lubricant pockets (9) for receiving lubricant are integrated.

5. Spacer body according to one of claims 1 to 4, characterized in that the wing jacket (8) is geometrically adapted to the raceway of the rotary ball joint.

6. spacer body according to one of claims 1 to 5, characterized in that the spacer body is made of plastic.

7. Spacer body according to one of claims 1 to 6, characterized in that the ball receptacles (5) in the region of their bottom (11) have a recess for providing a spherical zone-shaped contact surface (12) adapted to the spherical shape.

8. Spacer body according to one of claims 1 to 7, characterized in that the individual wings (6) are arranged in wing groups (13), the spacing of the wing groups (13) from one another greater than the spacing of the wings (6) within each of the Groups (13) is.

9. Spacer body according to one of claims 1 to 8, characterized in that the wings (6) are designed as star-shaped protruding plates which extend axially with respect to an axis (A) of the spacer body defined by the ball seats.

10. Spacer body according to one of claims 1 to 9, characterized in that the wings (6) are at least partially connected by at least one transverse web (14) which is formed on the outside of the ball seats (5).

11.Abstandshalterkörper according to claim 10, characterized in that the transverse web (14) is formed circumferentially and connects all the wings (6) with one another.

12. Spacer body according to claim 10 or 11, characterized in that the transverse web (14) is flush with the wing shells (8) of the wings (6) connected by the transverse web (14), simulating their outer contour.

13. Spacer body according to one of claims 10 to 12, characterized in that the transverse web (14) radially on the outside has a web width (15) in the range of 3% to 30% of the axial extent of the spacer body.

14. Spacer body according to claim 13, characterized in that the web width (15) of the transverse web (14) increases in the radial direction from the inside to the outside.

15. Ball bearings with two mutually rotatable bearing rings and with at least one row of balls arranged so that they can roll between the bearing rings, characterized in that the balls are held at a distance from one another in the ball bearing by spacer bodies according to one of claims 1 to 14.