Bearing cages and their uses

Abstract

To provide a oneway snap-in bearing cage which can avoid interference occurring between the oneway snap-in bearing cage and a roller at the application of an effect of an umbrella which is deformed by the expansion of a hang-down part to the outside by the application of a centrifugal force as a rotational speed is increased.SOLUTION: A oneway snap-in bearing cage 1 includes a substantially-annular backbone 10, and a hang-down part 20 extending from the backbone 1 to one axial direction side. The hang-down part comprises pockets arranged with intervals in a circumferential direction, and used for accommodating spherical rollers 21, and a pocket connecting part 24 connecting the adjacent pockets. The pocket employs expansion form design for achieving separation from a surface of the roller at least in the vicinity of a radial inner edge 28 at its opening side. When an umbrella effect is generated, an inner wall lower edge part of the pocket at the opening side hardly interferes with the roller, and various problems caused by a conventional umbrella effect can be eliminated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a one-way snap-in bearing cage and to a roller bearing using such a cage. [Background technology]

[0002] One-way snap-in cages are a conventional configuration in roller bearings due to their low cost and ease of installation. As shown in Figures 1 and 2, a typical one-way snap-in cage 1 is axially divided into a generally annular backbone 10 and a depending portion 20 extending from the backbone 10 on one side in the axial direction. The depending portion 20 includes circumferentially spaced pockets 22 for receiving spherical rollers 21 and pocket connections 24 connecting adjacent pockets. Conventional cages accommodate spherical rollers and employ spherical pockets that are slightly larger than the rollers, with the pockets and rollers having a covered clearance fit. This fit not only facilitates the fit of the rollers, but also helps to form a stable lubricating oil film between the pockets and the rollers. The pockets 22 form prongs 26 at their open sides, which protrude axially beyond the pocket connections 24. In other words, the pocket connections 24 are axially "set back" from the tip range of the prongs 26. This allows the mass of the hanging portion to be reduced, and the effect of centrifugal force to be reduced.

[0003] An inherent drawback of snap-in cages is that as the rotational speed increases, the pendant parts tend to deform by expanding outward under the action of centrifugal force, forming the so-called "umbrella effect". The umbrella effect can cause the pockets to lose their alignment with the rollers, resulting in pocket-roller interference, localized overheating of the cage, and localized melting. More seriously, interference can easily occur at the radially inner edge 28 of the cage's open-side inner wall, and the contact forces at this location can easily cause deformation of the entire cage. In severe cases, this can cause the cage to come off the rollers.

[0004] To solve the above technical problems, the existing solution is generally to enlarge the pocket diameter to increase the gap between the inner surface of the pocket and the roller, thereby avoiding the interference between the cage (especially the radial inner edge of the prong) and the roller. However, this type of solution has many negative effects, including: The cage easily comes off the roller due to the loose fit between the cage and the roller; When the axial space of the bearing is limited, the increase in the pocket diameter will "compress" the axial dimension of the backbone, weakening the overall stiffness of the backbone. Summary of the Invention [Means for solving the problem]

[0005] The present invention is directed to the technical problem of interference between a one-way snap-in bearing cage and a roller under the action of the umbrella effect. To solve the above problem, the present invention provides a one-way snap-in cage, including a substantially annular backbone and a hanging part extending from the backbone in one axial direction. The hanging part includes pockets for accommodating spherical rollers spaced apart in the circumferential direction, and pocket connections for connecting adjacent pockets. The pockets are designed to be separated from the roller surface at least near the radial inner edge of the opening side inner wall. When the umbrella effect occurs, this expansion structure can avoid interference between the lower edge of the opening side inner wall of the pocket and the roller to a certain extent, and various problems caused by the conventional umbrella effect can be avoided.

[0006] Based on the above cage, the present invention further provides a roller bearing, including an inner race, an outer race, and at least one row of rollers disposed between the inner race and the outer race. The cage is disposed on the at least one row of rollers. The roller bearing using the above cage can rotate at high speed and greatly reduce the temperature rise effect under the same rotation speed condition, so that it has a high rotation speed advantage and good application prospects.

[0007] Various embodiments and beneficial effects of the present invention are described in detail below in conjunction with the drawings. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a three-dimensional perspective view of a conventional spherical pocket cage. [Diagram 2] FIG. 2 is a partial enlarged view of region A in FIG. [Figure 3a] FIG. 1 is a geometrical schematic illustrating the mechanism of formation of a toroidal surface. [Figure 3b] FIG. 1 is a geometrical schematic illustrating the mechanism of formation of a toroidal surface. [Figure 4] FIG. 2 is a radial perspective view of the toroidal surface pocket cage of the present invention; [Diagram 5] FIG. 2 is a radial cross-sectional view of the toroidal surface pocket cage of the present invention. [Figure 6] FIG. 6 is a partial enlarged view of region B in FIG. 5. [Figure 7] FIG. 6 is a partial enlarged view of region C in FIG. 5. [Figure 8] FIG. 1 is a cross-sectional view of a plane determined by the geometric centers of all the pockets of the cage. [Figure 9] FIG. 9 is a partial enlarged view of region B in FIG. 8. [Figure 10] FIG. 9 is a partial enlarged view of region C in FIG. 8. [Figure 11] FIG. 5 is a cross-sectional view of the cage taken along the FF direction in FIG. 4. [Figure 12] FIG. 12 is a partial enlarged view of region B in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] For convenience of explanation, the direction indicated by the axis of the bearing in the present invention (dotted lines in Fig. 1 and Fig. 4) is defined as "axial direction", and the direction perpendicular to the axis is defined as "radial direction". Furthermore, in the drawings, the ball center of the roller is shown to be in the geometric center of the pocket. This is done to facilitate observation of the present invention, and does not intentionally indicate that the roller is always located in the geometric center of the pocket when the bearing in the present invention is in an operating state. Various embodiments of the present invention are described in detail below in conjunction with the drawings, and all identical or similar components are given the same reference label.

[0010] As mentioned above, the location where the cage and roller interference is most likely to occur is near the radial inner edge of the opening side inner wall of the pocket. This is marked with label 28 in the drawings, and is also referred to as the "inner wall lower edge" below. This is because, constrained by the backbone, the opening side of the pocket has a larger deformation due to the outward expansion of the cage's drooping part than the vicinity of the backbone, so the interference positions of the pocket and the roller are relatively concentrated near the opening side inner wall lower edge of the pocket. Theoretically, the inner wall lower edge covers a certain range in both the axial and radial directions of the bearing. This is because the umbrella effect is positively correlated with the rotation speed of the bearing. When the rotation speed is different, the contact positions of the roller and the opening side inner wall of the pocket do not completely match. Therefore, the interference area needs to be a set of positions where the inner wall of the pocket actually interferes with the roller under the umbrella effect, and these positions are relatively concentrated near the position of the opening side inner wall lower edge of the pocket.

[0011] In order to eliminate the adverse effect of interference between the radial inner edge of the pocket inner wall and the roller, the design of the present invention uses a toroidal surface pocket cage. A toroidal surface is a geometric concept, specifically, a curved surface in space obtained by rotating a circle on a plane once around a chord on the circumference. Figures 3a and 3b are geometric schematic diagrams showing the mechanism of the formation of a toroidal surface. As can be seen from the figures, the formed toroidal surface can be divided into two parts. One is formed by the rotation of a minor arc a1 with an arc length shorter than a semicircle around the chord L, and has a shape similar to a rugby ball. The other part is formed by the rotation of a major arc a2 with an arc length larger than a semicircle around the chord L, and has a shape similar to a pumpkin. The toroidal surface pocket of the present invention uses a toroidal surface of the former shape. The circle forming the toroidal surface is defined as the "section circle" in the present invention, and the chord L is defined as the "rotation axis" in the present invention.

[0012] FIG. 4 is a three-dimensional perspective view of the toroidal surface pocket cage of the present invention from a radial direction. FIG. 5-FIG. 7 are radial cross-sectional views of the cage of the present invention and their respective enlarged partial views. In order to show the difference between the toroidal surface pocket and the spherical pocket, the (virtual) profiles or surfaces Pw, Ps, Pt of the roller, the spherical pocket, and the toroidal surface pocket are simultaneously displayed in FIG. 6 and FIG. 7. From the figures, it can be seen that the surface profile Pt of the toroidal surface pocket is formed by rotating a cross-sectional circle S of a larger radius than the spherical pocket surface profile Ps around the rotation axis L. The rotation axis L passes radially through the geometric center c1 of the pocket (shown in the figure to coincide with the ball center of the roller), but does not pass through the circle center c2 of the cross-sectional circle. As can be seen from FIG. 7, the distance d1 between the surface profile Pt of the toroidal surface pocket and the roller surface Pw of the radial inner edge 28 on the backbone side is larger than the distance d2 between the roller surface Pw at the same position as the surface profile Ps of the conventional spherical pocket.

[0013] The same situation exists at other radially inner edge positions of the pocket inner wall around the roller. Figures 8 to 10 are cross-sectional and partially enlarged views of the toroidal surface pockets seen from the axial direction. The cross-section is determined jointly by the geometric centers of all pockets. It can be seen from the figures that the distance d1 between the radially inner edge of the pocket and the roller surface is much larger than the gap d2 between the conventional spherical pocket and the roller. Figures 11 and 12 are cross-sectional and partially enlarged views of the cage of the FF of Figure 4. Similarly, it can be seen that the distance between the roller surface and the toroidal surface pocket at its opening side radially inner edge is much larger than the distance between the conventional spherical pocket and the roller (not marked in the figures).

[0014] 4 to 12 show, from different angles and positions, how the inner wall of the pocket, at least the radial inner edge, forms an expansion structure to achieve separation from the roller surface, thereby increasing the gap between itself and the roller surface, and the gap is at least larger than the distance between the conventional spherical pocket and the roller. It is not difficult to imagine that when the umbrella effect occurs, the lower edge of the inner wall of the pocket moves radially upward and approaches the surface of the roller, and further, when it approaches the opening side of the pocket, the pushing effect becomes more pronounced (not shown). The toroidal pocket has a shape that spreads outward overall compared to the spherical pocket, and is designed to have a larger and larger distance from the roller surface, so that when the umbrella effect occurs, its radial inner edge is less likely to contact the roller surface than the conventional spherical pocket. In this way, the toroidal pocket design can effectively avoid the interference problem that occurs between the conventional spherical pocket and the roller under the umbrella effect, and various adverse effects resulting therefrom.

[0015] As can be seen from Figures 6 and 9, the larger the cross-sectional circle S forming the toroidal surface pocket, the larger the gap d1 between the radial inner edge of the pocket and the roller, and the less likely the interference problem caused by the umbrella effect will occur. Nevertheless, the larger the cross-sectional circle forming the toroidal surface pocket is, the better it is. This is because, as the diameter of the cross-sectional circle increases, the degree of fit between the toroidal surface pocket and the shape of the roller gradually decreases, making it easier to impair the lubrication effect and increase vibration noise. Therefore, the cross-sectional circle forming the toroidal surface pocket must have an appropriate range. Within this range, it is possible to effectively overcome many problems caused by the umbrella effect without impairing the fit between the pocket and the roller due to the cross-sectional circle being too large.

[0016] Experiments have shown that the radius Rs of the cross-sectional circle forming the toroidal surface pocket (see Figs. 6 and 9) must be within the range of 1.08 to 10 times the roller radius Rw. In a preferred embodiment, the radius Rs of the cross-sectional circle must be within the range of 1.15 to 5 times the roller radius Rw. In a more preferred embodiment, the radius Rs of the cross-sectional circle must be within the range of 1.25 to 1.6 times the roller radius Rw. The toroidal surface pocket in the above size range can accommodate different degrees of umbrella effect, has good heat dissipation, and is particularly suitable for roller bearings rotating at medium to high speeds.

[0017] The inner surface of the cage pocket described above adopts a toroidal surface design as a whole, the core idea of ​​which is to move the radial inner edge of the pocket away from the roller surface compared to the conventional spherical pocket, thereby overcoming the interference problem caused by the umbrella effect. It is not difficult to understand that other different technical solutions can be derived from the same idea, without being limited to the embodiment in which the toroidal pocket is used as a whole. For example, the pockets of various shapes, including spherical and toroidal, can be locally modified to form a structure with a locally flared shape near the radial inner edge, thereby achieving the technical effect of being locally away from the roller surface in each case. In summary, the shape of the pocket curved surface can achieve the object of the present invention as long as the area close to the radial inner edge is farther away from the roller surface than the other parts of the pocket curved surface.

[0018] Specifically, the radially inner edge of the pocket can locally adopt a design characterized by a conical surface, a toroidal surface, or a spherical surface of an expanding shape, or any other shape of curved surface, as long as this part of the curved surface is further from the roller surface than the other parts of the pocket surface and forms an effective continuation of the other parts of the surface. Taking a spherical shape as an example, the pocket comprises a spherical pocket lower edge with a large radius of curvature, forming a forward continuation of the remaining pocket surface with a small radius of curvature (the cross section is usually shown as two internal tangent circles), and further comprises a spherical pocket lower edge with any radius of curvature, forming a reverse continuation of the remaining part of the pocket surface (the cross section is usually shown as two external tangent circles). The above method not only forms a shape of the radially inner edge of the pocket locally expanding outwards, but also achieves a smooth transition between different curved surfaces, which is particularly useful for eliminating stress concentrations, thereby preventing material wear.

[0019] Those skilled in the art should understand that the various technical features of the present invention described above can be implemented independently or used in combination, without being limited to a specific embodiment. Any modification or improvement of the cage and roller bearing using the cage described above shall fall within the protection scope of the present invention as long as it complies with the definition of the attached claims. [Explanation of symbols]

[0020] 1 One-way snap-in bearing cage 10. Backbone 20 Drooping part 21 Spherical Roller 22 Pocket 28 Radial inner edge

Claims

1. A one-way snap-in bearing cage (1) comprising a generally annular backbone (10) and a depending portion (20) extending from said backbone (10) on one axial side, said depending portion (20) comprising pockets (22) spaced apart in the circumferential direction and used to receive spherical rollers (21), and pocket connections (24) connecting adjacent pockets (22); The one-way snap-in bearing cage (1) is characterized in that the pocket (22) has a toroidal surface shape, and the radius Rt of the cross-sectional circle of the toroidal surface is 1.08 to 10 times the radius Rw of the roller (21).

2. The one-way snap-in bearing cage (1) according to claim 1, characterized in that the radius Rt of the cross-sectional circle of the toroidal surface is 1.15 to 5 times the radius Rw of the rollers.

3. The one-way snap-in bearing cage (1) according to claim 2, characterized in that the radius Rt of the cross-sectional circle of the toroidal surface is 1.25 to 1.6 times the radius Rw of the rollers.

4. The one-way snap-in bearing cage (1) according to any one of claims 1 to 3, characterized in that the opening side inner wall of the pocket near its radially inner edge forms, together with other parts of the pocket, an arcuate transition between different curved surfaces.

5. A roller bearing comprising an inner race, an outer race, and at least one row of rollers disposed between the inner race and the outer race, A roller bearing, characterized in that a one-way snap-in bearing cage (1) according to any one of claims 1 to 4 is arranged on said at least one row of rollers.

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