Cageless rolling bearing

Abstract

The present invention relates to a cageless rolling bearing (1) comprising a plurality of rolling elements (4) distributed in the circumferential direction between an inner ring (2) and an outer ring (3) arranged concentrically with the inner ring (2), and a pressing element (6) arranged in the shape of a ring segment along the circumferential direction, which is in at least temporary contact with at least two of the rolling elements (4) simultaneously and applies an axially directed force to each of the rolling elements (4) in contact with each other.

Description

[Technical field]

[0001] The present invention relates to a cageless rolling bearing. [Background technology]

[0002] Rolling bearings used in applications where relatively high rotational speeds (rpm n x dm > 10 000 mm / min) are expected are typically equipped with a bearing cage in which the rolling elements (balls, rollers) of the rolling bearing are received. This type of bearing cage allows an economical life and uniform concentric operation to be achieved. Furthermore, the bearing cage ensures that the rolling elements are kept equally spaced from one another and prevents tribologically unfavorable contact between the rolling elements during operation of the rolling bearing.

[0003] Rolling bearings without a bearing cage are also known. These are also called cage-free rolling bearings. The advantage of these cage-free rolling bearings is, for example, that by omitting the bearing cage, more rolling elements can be provided for the same size of the rolling bearing, which increases the load-bearing capacity of the rolling bearing. Rolling bearings of this kind are also called full rolling bearings. However, the above-mentioned advantages of rolling bearings with a bearing cage are not achieved at all in the known cage-free rolling bearings. The omission of the bearing cage creates problems, especially at high rotational speeds: the spacing between the individual rolling elements changes and contacts can occur between them. Unwanted contacts of this kind increase wear and reduce the service life of the rolling bearing. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to prevent contact between adjacent rolling elements during operation of a rolling bearing. As much as possible The present invention aims to provide a rolling bearing without a blocking cage. [Means for solving the problem]

[0005] This problem is solved by the features of claim 1. Advantageous embodiments are set forth in the dependent claims.

[0006] The cage-free rolling bearing according to the invention has a number of rolling elements distributed in the circumferential direction between an inner ring and an outer ring arranged concentrically with respect to the inner ring, and a pressing element arranged in the form of a ring segment along the circumferential direction, which is at least temporarily in contact with at least two of the rolling elements simultaneously and exerts an axially directed force on each of the rolling elements in contact with each other.

[0007] The term "axial" refers to the axial direction of the inner and outer rings of the concentrically arranged rolling bearing. Furthermore, the expression "axially directed force" should be understood in such a way that the direction acting on the rolling elements by the pressure elements has one directional component in the axial direction. Therefore, under this definition, there are not only strictly axial forces, but also forces that, in addition to the axial component, also have, for example, radial components.

[0008] During operation of the rolling bearing, the pressure element has a compensating effect on the spacing between adjacent rolling elements. For example, if the spacing between the leading and trailing rolling elements is smaller than the theoretical spacing that should result based on an equal distribution of the rolling elements, the braking action of the pressure element on the leading rolling element is small. The spacing between these rolling elements is correspondingly larger. On the other hand, if the spacing between the leading and trailing rolling elements is larger than the theoretical spacing, the braking action of the pressure element on the leading rolling element is large. The spacing between these rolling elements is correspondingly smaller.

[0009] In this way, the distance between the individual rolling elements is adjusted to the theoretical distance, so that contact between adjacent rolling elements during operation of the rolling bearing is largely prevented, which correspondingly increases the service life of the rolling bearing, making the cageless rolling bearing particularly suitable for applications involving high rotational speeds.

[0010] In an advantageous embodiment, the pressure element is stationary or stationary. In the case of a rolling bearing, generally either the inner or outer ring is stationary, while the respective other ring rotates at the required speed depending on the application. The rolling elements roll on the respective running surfaces of the inner and outer rings during operation. Furthermore, other components of the rolling bearing, which are usually also stationary, for example a cover disk, may be provided. Being stationary or stationary means that the pressure element is connected to one of the stationary elements of the rolling bearing (for example a stationary ring, a cover disk or an adjacent component). As a result, a relative movement of the rolling elements with respect to the pressure element occurs. Thus, during the rotational movement of the rolling bearing, all the rolling elements come into contact with the pressure element in turn. The advantage of forming the pressure element as a stationary or stationary pressure element is that this is relatively easy to control from a technical point of view.

[0011] However, it is also possible for the pressure element to be formed as a rotating pressure element, which is then mounted on a rotating element of the rolling bearing, for example on a rotating ring. The pair of rolling elements typically rotates approximately at the average speed of the outer and inner rings, so that approximately the same relative movement is provided between the pair of rolling elements and the pressure element, and the principle of action of the pressure element is approximately the same.

[0012] In other words, the pressing element exerts a certain force on the rolling body, thereby locally influencing its rotational speed and thus controlling the spacing of the rolling body. This is achieved in that the pressing element is configured in terms of its elastic form and elastic adjustment such that a different force distribution occurs for the leading and trailing rolling body depending on whether the trailing rolling body is more or less spaced from the leading rolling body. For example, the contact force between the pressing element and the rolling body brakes the rotational speed of the rolling body by being directed in the axial direction away from the bearing shoulder of the inner ring of the rolling bearing or towards the bearing shoulder of the outer ring. This allows a separation effect to be achieved by a high contact force on the trailing rolling body, which is close to the critical distance.

[0013] The advantages of the cage-less rolling bearing according to the present invention are as follows: In bearings without assembly-related packing density limitations, a higher number of rolling elements allows for a higher load-bearing capacity, especially in bearings in which at least one retention flange is at least partially removed by eliminating the space for an intermediate strip of the cage separating the rolling elements (e.g. stepped ball bearings, spindle bearings, slotted bearings, etc.). Reduced friction due to elimination of friction points between the cage pockets and the rolling elements on the guideways of the rotating cage and hysteresis losses in the cage material caused by forcing forces. Elimination of non-recursive rotational deviations in the running characteristics of the bearing induced by the cage running and co-rotating within its own eccentric, rotational and elastic degrees of freedom. Compensating or reducing the contact angle between the rolling elements and the outer and inner bearing rings, resulting in a more favorable kinematic situation during rolling of the rolling elements with respect to the ball-to-roll ratio and the leading and trailing balls.

[0014] In a preferred embodiment, the pressure element has a pressure tongue which is supported in the first end region, the support of the pressure tongue being preferably effected via a projection which serves as a bearing stand, by means of which the pressure element is connected in a non-rotatable manner with the rolling bearing or with one of the surrounding stationary elements.

[0015] The second region of the pressure tongue, which is opposite the first end region of the pressure tongue, can advantageously be free end By being configured as a cantilevered tongue (like a cantilever), the pressure element acquires elasticity for exerting a variable axial force on each rolling element it comes into contact with. In this way, the spacing between adjacent rolling elements can be adjusted particularly precisely.

[0016] However, the second end region of the pressure tongue can also be flexibly fixed for stability reasons.

[0017] In an advantageous embodiment, the cross section of the pressure tongue tapers from the first end toward the second end. Correspondingly, the second end region has a smaller cross section than the first end region. In this way, the elastic distribution or the bending moment of the pressure element can be adjusted. This also allows a particularly precise adjustment of the distance between adjacent rolling elements. The taper of the cross section can be achieved by reducing the thickness and / or width of the pressure tongue.

[0018] Furthermore, in the first end region of the pressure tongue, a chamfered inlet region can be formed, which ensures that the axial force is gently introduced at the beginning of contact between the respective rolling body and the pressure element.

[0019] Furthermore, a chamfered outlet region can be formed in the second end region, which provides for a gentle termination of the force application at the end of contact between the respective rolling body and the pressure element.

[0020] In a further advantageous embodiment, the pressure tongue is curved or arcuate, which also influences the elastic pretension (e.g. the elastic adjustment) of the pressure element, so that the distance between two adjacent rolling bodies can be adjusted particularly precisely.

[0021] In a further advantageous embodiment, the pressure element is configured as a seesaw-shaped pressure element, which is supported in the middle region and flexibly fixed in the end regions or is completely cantilevered, in this way the pressure element acts as a kind of elastic seesaw and can accelerate the leading rolling element more strongly when the trailing rolling element follows critically.

[0022] According to the invention, it is necessary to apply a force in the axial direction to at least two rolling bodies simultaneously by the pressing element for a short time. However, it is also possible to apply a force in the axial direction to more than two rolling bodies simultaneously by the pressing element. In this way, the spacing between the rolling bodies can be adjusted over a long period of time. This reduces the possibility of undesired contact between adjacent rolling bodies.

[0023] It is also possible to arrange several pressure elements distributed over the circumference, which also additionally reduces the possibility of undesired contact between adjacent rolling elements.

[0024] In an advantageous embodiment, the rolling bearing is configured as a stepped ball bearing, the rolling bodies being pressed by the pressure element in the direction of the outer ring shoulder of the stepped ball bearing, in which case a particularly constant force introduction is possible by the pressure element. [Brief description of the drawings]

[0025] The invention will be further explained on the basis of embodiments in the drawings. [Figure 1] FIG. 2 is a cross-sectional view of a rolling bearing without a cage. [Diagram 2] 2 is a front view of the rolling bearing of FIG. 1, with the cover disk omitted. [Diagram 3]FIG. 3 is a view showing one of the pressing elements of FIG. 2 in isolation; [Figure 4] FIG. 4 is a side view of the pressing element of FIG. 3; [Diagram 5] FIG. 2 is a principle diagram of a pressing element with two rolling bodies in contact with the pressing element. [Figure 6] FIG. 13 shows another embodiment of a pressure element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] FIG. 1 shows a cage-free rolling bearing 1 in a cross-section. The rolling bearing has an inner ring 2 and an outer ring 3 arranged concentrically relative to the inner ring 2. Between the inner ring 2 and the outer ring 3, a ring-shaped bearing interior space is formed. A number of rolling elements 4 are distributed in this bearing interior space at equal intervals in the circumferential direction. A ring-shaped cover disk 5 forms the axial end of the rolling bearing 1 on the right hand side in FIG. 1. Between this cover disk 5 and the inner ring 2 and / or the outer ring 3, sealing elements can be provided, which are not shown in detail in the figure.

[0027] 2 shows a front view of the rolling bearing 1 of FIG. 1, but for the sake of clarity, without showing the cover disc 5. In addition to the inner ring 2, the outer ring 3, the rolling elements 4 and the cover disc 5, the rolling bearing 1 has a total of three pressure elements 6.

[0028] The pressure elements 6 are fixed to the cover disk 5 and are equally spaced apart in the circumferential direction. Each pressure element 6 has the basic shape of a ring segment and covers a corresponding ring segment of the bearing interior space. The angular range covered by each pressure element 6 is such that at least two rolling elements 4 are temporarily contacted by the pressure element 6 at the same time. Each pressure element 6 then exerts an axially directed force on the rolling elements 4 in contact with each other. More precisely, the pressure element 6 exerts an axial force on the rolling elements 4 that is directed from the right to the left in FIG. 1. As a result, the rolling elements 4 are pressed by the pressure element 6 in the direction of the shoulder of the outer ring 3.

[0029] Figures 3 and 4 show the pressure element 6 of Figures 1 and 2 in isolation. Figure 4 shows the pressure element 6 from the same direction as in Figure 2. Figure 3 shows the pressure element 6 in a side view.

[0030] The pressure element 6 has a pressure tongue 7 and a projection 8. The projection 8 is formed in a first end region 7a of the pressure tongue 7 and serves to fasten the pressure element 6 to the cover disk 5. The pressure element 6 is thus supported at the first end region 7a. A second end region 7b of the pressure tongue 7, which faces the first end region 7a, is supported at the first end region 7b. free end 4, the pressure tongue 7 is formed with a bent or curved inlet region 7c. That is, the second end region 7b is not supported. The cross section of the pressure tongue 7 tapers from the first end region 7a in the direction of the second end region 7b. More precisely, the thickness of the pressure tongue 7 decreases, whereas the width of the pressure tongue 7 remains constant. In the first end region 7a, a chamfered inlet region 7c is formed. In the second end region 7b, a chamfered outlet region 7d is formed. As can be seen in particular in FIG. 4, the pressure tongue 7 is formed with a bent or curved inlet region 7c.

[0031] Figure 5 shows diagrammatically the functional principle of a cage-free rolling bearing 1. One pressure element 6 and, by way of example, two rolling bodies 4a, 4b are shown. The position shown in dashed lines is the position that the pressure element 6 would occupy in the absence of the rolling bodies 4a and 4b. The two rolling bodies 4a, 4b press the pressure element 6 into the position shown in solid lines. At the same time, the pressure element 6 exerts a corresponding reaction force on the two rolling bodies 4a and 4b. This reaction force corresponds to the axial force that the pressure element 6 exerts on the rolling bodies 4.

[0032] During operation (i.e. during rotation) of the rolling bearing 1, the rolling body 4a is the leading rolling body and the rolling body 4b is the trailing rolling body. That is to say, the rolling body 4a first comes into contact with the pressing element 6 in the inlet region 7c and then advances from the first end region 7a in the direction of the second end region 7b. The trailing rolling body 4b correspondingly comes into contact with the pressing element 6 later in the inlet region 7c and also advances from the first end region 7a in the direction of the second end region 7b. The leading rolling body 4a first reaches the second end region 7b and then loses contact with the pressing element 6 via the outlet region 7d. At the same time, the rolling body 4 following the rolling body 4b has already passed the inlet region 7c. The rolling body 4b is followed by this new trailing rolling body corresponding to the leading rolling body.

[0033] Now, if the interval between the leading rolling body 4a and the trailing rolling body 4b is smaller than the theoretical interval that should be generated based on the equal spacing of the rolling bodies 4, the braking action of the pressing element 6 on the leading rolling body is small. The interval between the rolling bodies 4a and 4b becomes correspondingly large. On the other hand, if the interval between the leading rolling body 4a and the trailing rolling body 4b is larger than the theoretical interval, the braking action of the pressing element 6 on the leading rolling body 4a is large. The interval between the rolling bodies 4a and 4b becomes correspondingly small.

[0034] Therefore, the distance between the rolling elements 4a and 4b is adjusted to a theoretical distance, thereby reliably preventing contact between the adjacent rolling elements 4a and 4b during operation of the rolling bearing 1.

[0035] FIG. 6 shows another embodiment of the pressure element. The pressure element 106 shown in FIG. 6 differs from the pressure element 6 shown in the previous figure in that the pressure tongue 107 is shaped differently. The pressure tongue 7 of the pressure element 6 has a constant width, whereas the pressure element 107 has a tapered width. More precisely, the width of the pressure element 107 narrows starting from the first end region 107a in the direction of the second end region 107b. The second end region 107b has a correspondingly smaller cross section than the first end region 107a. In this way, the pressure element 106 has a different elastic distribution or bending moment of resistance than the pressure element 6.

[0036] In the exemplary embodiments shown in the figures, the rolling elements 4 are embodied as spheres. Correspondingly, the rolling bearing 1 is embodied as a ball bearing, more precisely as a stepped ball bearing. However, it is also possible for the rolling elements 4 to be tubular, i.e. as rollers or cylinders.

[0037] In the embodiment shown in the figures, three pressure elements 6 are arranged at equal intervals. However, it is also possible to provide another quantity of pressure elements or even just one pressure element 6.

[0038] In the embodiment shown in the figures, the rolling bearing 1 is configured as a full rolling bearing. A high load-bearing capacity is achieved by almost completely filling the bearing interior space with rolling elements 4. However, it is also possible to pack the rolling elements 4 less densely.

[0039] In the embodiment shown in the figures, the pressure element 6 is connected to the cover disk 5. However, it is also possible for the pressure element 6 to be connected to other stationary or stationary components of the rolling bearing or to a retaining element arranged adjacent to the rolling bearing. Furthermore, it is also possible for the pressure element 6 to be arranged on a rotating element of the rolling bearing 1, for example on the rotating inner ring 2 or outer ring 3.

[0040] In the exemplary embodiments shown in the figures, the pressure element 6, 106 is formed as a pressure element with a pressure tongue 7 or 107, respectively. In this case, the second end region 7b or 107b, respectively, is formed completely cantilevered. However, it is also possible to fix the second end region 7b or 107b in a flexible manner.

[0041] It is also possible to provide one or more pressure elements which are configured as seesaw-shaped pressure elements, which are supported in a central region and either flexibly fixed or cantilevered in the end regions, such an arrangement of the pressure elements is particularly advantageous for alternating axial orientation of the pressure forces. [Explanation of symbols]

[0042] 1. Rolling bearings without cages 2. Inner Circle 3 Outer ring 4, 4a, 4b Rolling elements 5 Cover Disc 6,106 Pressing elements 7,107 Pressing tongue 7a, 107a First end region 7b, 107b Second end region 7c entrance area 7d exit area 8 Protrusion

Claims

1. a plurality of rolling elements (4) disposed in a circumferential direction between an inner ring (2) and an outer ring (3) disposed concentrically with the inner ring (2); a pressing element (6) arranged in a ring segment along the circumferential direction, which is in at least temporary contact with two of the rolling bodies (4) simultaneously and exerts an axially directed force on each of the rolling bodies (4); Equipped with In a cage-free rolling bearing (1), the pressure element (6) has a pressure tongue (7) which is cantilevered at its first end region (7a) and whose second end region (7b) is formed as a free end, A chamfered inlet region (7c) is formed in said first end region (7a), A chamfered outlet area (7d) is formed in said second end area (7b), a pressing element (6) having an elastic pretensioning force or an elastic adjustment amount set so that if the interval between a leading rolling element (4a) and a trailing rolling element (4b) is smaller than a theoretical interval that should result based on an equal spacing distribution of the rolling elements (4), the braking action of the pressing element (6) on the leading rolling element (4a) is small, and if the interval between the leading rolling element (4a) and the trailing rolling element (4b) is larger than the theoretical interval, the braking action of the pressing element (6) on the leading rolling element (4a) is large.

2. 2. The cage-less rolling bearing (1) according to claim 1, wherein the cross section of the pressure tongue (7) tapers starting from the first end (7a) to the second end region (7b).

3. 3. The cage-less rolling bearing (1) according to claim 1 or 2, wherein the pressure tongues (7) are curved in the axial direction.

4. 4. The cage-free rolling bearing (1) according to claim 1, wherein the rolling bearing (1) is closed in the axial direction by a ring-shaped cover disk (5), on which the pressure element (6) is attached.

5. 5. The cage-less rolling bearing (1) according to claim 1, wherein the pressure element (6) is in contact with at most two of the rolling bodies (4) simultaneously.

6. 6. The cage-less rolling bearing (1) according to claim 1, wherein the pressure elements (6) are equally spaced and distributed over the circumferential direction.

7. 7. The cageless rolling bearing (1) according to claim 1, wherein the rolling bearing (1) is a stepped ball bearing.

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