CN112943797A - Rolling bearing - Google Patents

Abstract

The invention relates to a rolling bearing, comprising two rows of rolling bodies; an outer ring configured with an inner raceway for rolling bodies; an inner ring configured with an outer raceway for rolling elements; and two cages (2) which are arranged axially next to one another between the outer ring and the inner ring and are each used for two rows of rolling elements, wherein an axial end (21) of the cage (2) which is located axially inside the rolling bearing is coated with an anti-adhesive coating (5), wherein the anti-adhesive coating (5) is composed of a material which has a lower coefficient of friction with respect to a lubricant used for the rolling bearing than the material from which the cage (2) is made.

Description

Rolling bearing

Technical Field

The invention relates to the technical field of bearings. The invention relates in particular to a rolling bearing.

Background

The wheelset bearing can be used in the axle box of a train bogie.

For example, chinese patent document CN 102951170B discloses an axle box unit for a railway vehicle bogie. The axle housing mentioned comprises a rolling bearing and an axle housing accommodating the rolling bearing. In this solution, the rolling bearing is configured as a double row tapered roller bearing, which specifically comprises two rows of tapered rollers, an outer ring configured with inner raceways for the tapered rollers, and an inner ring configured with outer raceways for the tapered rollers. Each row of tapered rollers is held stably between the outer race and the inner race by a cage.

For another example, chinese patent document CN 105570290B also discloses an axle box bearing unit for a train wheel axle. The axle housing bearing unit also comprises, analogously to the above-described axle housing unit, a rolling bearing designed as a double-row tapered roller bearing and a housing enclosing the rolling bearing.

In the wheel-to-bearing solutions described above, the grease used for lubricating the bearing is usually injected through a through-hole formed in the axially intermediate region of the bearing outer ring. As the wheelset bearing operates, grease located in the axially intermediate region of the wheelset bearing will gradually migrate toward the axial sides of the wheelset bearing. Therefore, the grease in the axially central region of the wheel set bearing will often be more grease than in the other regions of the wheel set bearing.

At present, with the continuous improvement of the speed per hour of a train, when a wheel set bearing rotates at a high speed, the temperature of lubricating grease in the wheel set bearing, particularly in the axial middle area of the wheel set bearing, rises violently, and the service life of the bearing is adversely affected.

At the same time, the requirements for bearing maintenance intervals are also increasing. For example, it is desirable to perform wheel-to-wheel maintenance after a greater range of travel of the train. In this case, more grease needs to be injected and a longer service life of the wheel set bearing needs to be ensured. However, the more grease in the wheelset bearing, the faster the wheelset bearing heats up during operation, and the bearing life may decrease.

Disclosure of Invention

Therefore, the object of the present invention is to provide a rolling bearing which can be adapted to the operating conditions of high-speed rotation. Preferably, the solution of the rolling bearing allows to optimize the bearing service life and the bearing maintenance intervals.

The above object is achieved by a rolling bearing. The rolling bearing includes: two rows of rolling bodies; an outer ring configured with an inner raceway for rolling bodies; an inner ring configured with an outer raceway for rolling elements; and two cages which are arranged axially next to one another between the outer ring and the inner ring and are each used for one row of rolling elements of the two rows of rolling elements, wherein an axial end of the cage which is located axially on the inside of the rolling bearing is coated with an anti-adhesive coating, wherein the anti-adhesive coating is composed of a material which has a lower coefficient of friction with respect to a lubricant used for the rolling bearing than the material from which the cage is composed.

According to a preferred embodiment, the release coating comprises polytetrafluoroethylene.

The rolling bearing is designed as a double-row rolling bearing. The outer ring is arranged in a circumferential manner radially outside the two rows of rolling bodies and is designed with two inner raceways for the rolling bodies. Alternatively, the outer ring can be formed by a separate outer ring member, wherein the radially inner side of the outer ring member is configured with two inner raceways for two rows of rolling bodies. Alternatively, the outer ring can comprise two outer ring members arranged axially side by side, wherein the radially inner side of each outer ring member is configured with one inner raceway for one row of rolling bodies. The inner ring is arranged radially inside the two rows of rolling elements and is designed with two outer raceways for the rolling elements. Alternatively, the inner ring can comprise two inner ring members arranged axially next to one another, wherein the radially outer side of each inner ring member is configured with one outer raceway for a row of rolling bodies. Alternatively, the inner ring can be formed by a separate inner ring component, wherein the radially outer side of the inner ring component is configured with two outer raceways for two rows of rolling bodies.

In the context of the present text, the terms "axial", "radial" and "circumferential" refer to the central axis, i.e. the axis of rotation, of the rolling bearing, unless otherwise stated.

The rolling bearing can be lubricated by a lubricant such as a lubricating oil or grease. Depending on the position of the lubricant duct, the lubricant is usually located in a large amount in the axial center region of the rolling bearing during the initial phase of the complete assembly or the complete maintenance, in particular between the rolling element raceway spaces each holding a row of rolling elements. In the rolling bearing provided herein, at least the respective axial end portions of the two cages close to the other cage are coated with an anti-sticking coating, for example, a coating containing polytetrafluoroethylene, the anti-sticking coating having a coefficient of friction against the lubricant that is smaller than the coefficient of friction of the material of which the cages are constructed against the lubricant, whereby friction between the lubricant and the above-mentioned axial end portions of the cages can be advantageously reduced. In particular in the case of a small distance of the axial ends of the cage from the inner ring and from the outer ring, the lubricant which accumulates in the axial middle region of the rolling bearing can therefore flow more easily through the respective axial ends of the two cages during operation of the rolling bearing by means of the anti-adhesive coating in a greater amount, so that a greater amount can enter the rolling body raceway space and flow further to both axial sides of the rolling bearing, thus better lubricating the raceways. In this case, the accumulation of the lubricant in the axially intermediate region of the rolling bearing can be reduced, whereby the temperature rise of the rolling bearing due to the accumulated lubricant and the large amount of friction during operation of the cage can be suppressed, and the service life of the rolling bearing can be extended. The rolling bearing provided can be adapted to the conditions of higher-speed rotation, for example, can meet the increasing requirements of high-speed trains. Still further, it is also possible to extend the maintenance interval of the rolling bearing by appropriately increasing the total amount of lubricant added in a single maintenance, while ensuring the required bearing service life and/or satisfying the actual rotational speed requirement.

In a preferred embodiment, the cage has two ring sections distributed in the axial direction and a plurality of beam sections connecting the two ring sections, wherein the ring sections of the cage which are located axially inside the rolling bearing are coated with an anti-adhesive coating. In the present embodiment, the cage is designed as a window cage, wherein two ring segments and two adjacent beam segments enclose pockets for retaining the rolling bodies. In this case, the anti-adhesive coating can be applied to the radially outer side, the radially inner side and/or the axial end side of the ring portion located on the axially inner side of the rolling bearing.

In alternative embodiments, the cage can also be designed as another type of cage. In this case, the cage can be coated with an anti-adhesive coating on the radial outer side, the radial inner side and/or the axial end side of the axial end of the rolling bearing which is located on the axial inner side.

According to a preferred embodiment, the axial end of the cage, which is located axially inside the rolling bearing, and/or the anti-sticking coating are configured such that the inner circumferential surface and/or the outer circumferential surface of the anti-sticking coating formed at the axial end extend in a direction oblique to the axial direction of the rolling bearing. In particular in rolling bearings in which the rotation axis of the individual rolling elements is not parallel to the revolution axis thereof, for example in tapered roller bearings, the raceway space for the rolling elements formed by the outer ring and the inner ring extends substantially along a plane formed by the rotation axis of the individual rolling elements, for example along a conical plane. In this case, by means of the structural design of the outer and/or inner circumferential surfaces of the axial ends of the cage and/or by means of the design of the anti-adhesive coating with respect to the thickness variation, the inner and/or outer circumferential surfaces of the anti-adhesive coating which are finally formed at the axial ends of the cage can be matched approximately to the raceway spaces of the rolling elements of the respective row, which facilitates the guiding of lubricant from the region between the two cages to the rolling element raceway spaces on both axial sides, so that the accumulation of lubricant in the axially central region of the rolling bearing is reduced.

Here, the rolling bearing is preferably configured as a double-row tapered roller bearing arranged in an O-ring configuration. In the O-configuration, the so-called "back-to-back" arrangement, the load center of action of each row of rolling elements lies outside the axial center line of the rolling bearing. Here, the inner circumferential surface of the anti-sticking coating layer finally formed at the axial end portion of the cage can have an inner diameter gradually increasing from the axially inner side toward the axially outer side of the rolling bearing. Alternatively or additionally, the outer circumferential surface of the anti-sticking coating layer finally formed at the axial end portion of the cage can have an outer diameter gradually increasing from the axially inner side toward the axially outer side of the rolling bearing.

Here, the rolling bearing is alternatively configured as a double-row tapered roller bearing arranged in an X-configuration. In an X-configuration, the so-called "face-to-face" arrangement, the load center of action of each row of rolling elements lies within the axial center line of the rolling bearing. Here, the inner circumferential surface of the anti-sticking coating layer finally formed at the axial end portion of the cage can have an inner diameter gradually decreasing from the axially inner side toward the axially outer side of the rolling bearing. Alternatively or additionally, the outer circumferential surface of the anti-sticking coating layer finally formed at the axial end portion of the cage can have an outer diameter gradually decreasing from the axially inner side toward the axially outer side of the rolling bearing.

In a further preferred embodiment, the cage is coated over its entire surface with an anti-adhesive coating. In this embodiment, the anti-adhesion coating is applied not only at one axial end of the cage but also in other areas of the cage. Therefore, after the lubricant enters the rolling body raceway space from the axial middle area of the rolling bearing, the local accumulation of the lubricant can be avoided or inhibited by the anti-sticking coating, and the lubricant can flow towards the two axial sides.

According to a preferred embodiment, the inner ring comprises two inner ring members arranged axially side by side, wherein a spacer ring is arranged axially between the two inner ring members.

In this case, it is advantageous if each of the two inner ring members is formed with a rib which is adjacent to the other inner ring member and which is formed with a chamfer connecting the outer circumferential surface and the axial end face of the rib. By means of the ramp configured in this way, the lubricant can be guided directly into the raceway space and can be guided, for example reflected, to the anti-adhesive coating of the cage and guided again through the anti-adhesive coating into the raceway space.

In this case, it is advantageous if each of the two inner ring members is formed with a rib which is adjacent to the other inner ring member and which is formed with notches which are distributed in the circumferential direction. With a slot configured in this way, lubricant can be guided directly into the raceway space and can be guided, for example reflected, to the anti-adhesive coating of the cage and guided again through the anti-adhesive coating into the raceway space. Furthermore, the provision of the notches also enables the lubricant storage capacity of the rolling bearing to be increased.

In this case, the radially outer side of the intermediate ring is advantageously configured with an annular groove. This makes it possible to store more lubricant by means of the annular groove and facilitates the guidance of lubricant into the rolling element raceway space during the movement of the rolling bearing.

According to a preferred embodiment, the outer ring is formed by a separate outer ring component, wherein the recess is formed in an axially intermediate region of the radially inner side of the outer ring component. Advantageously, the groove is connected to a through-hole for injecting lubricant. Advantageously, the recess is configured as an annular groove in an axially intermediate region of the outer ring member. This enables more lubricant to be stored by means of the groove.

Drawings

Preferred embodiments of the present invention are schematically illustrated in the following with reference to the accompanying drawings. The attached drawings are as follows:

fig. 1 is a half sectional view of a rolling bearing according to a first preferred embodiment of the present invention;

fig. 2 is a perspective half sectional view of a rolling bearing according to a second preferred embodiment of the present invention;

fig. 3 is a three-dimensional half sectional view of a rolling bearing according to a third preferred embodiment of the present invention;

fig. 4 is a perspective view of an inner ring of a rolling bearing according to a third preferred embodiment of the present invention; and

fig. 5 is a partially enlarged view of fig. 4.

Detailed Description

Fig. 1 shows a half sectional view of a rolling bearing according to a first preferred embodiment of the present invention. The rolling bearing according to the first preferred embodiment is configured as a double row tapered roller bearing. The rolling bearing can be used, for example, as a wheel set bearing in a train.

As shown in fig. 1, the rolling bearing includes an outer ring and an inner ring, rolling bodies (not shown) in the form of two rows of tapered rollers arranged radially between the outer ring and the inner ring, and two cages 2 for respectively holding the rolling bodies of one row.

The outer ring is circumferentially arranged radially outside the two rows of tapered rollers. In the present embodiment, the outer ring is constituted by a single outer ring member 1, wherein the radially inner side of the outer ring member 1 is configured with two inner raceways for tapered rollers arranged at intervals in the axial direction. A through hole 11 penetrating the outer ring member 1 in the radial direction is formed in an axially intermediate region of the outer ring member 1.

The inner ring is disposed radially inward of the two rows of tapered rollers. In the present embodiment, the inner ring comprises two inner ring members 3a arranged side by side in the axial direction, wherein the radially outer side of each inner ring member 3a is configured with one outer raceway for one row of tapered rollers. Each inner ring member 3a is configured with a stopper for stopping the tapered rollers, i.e., a first rib 31a located on the axially inner side of the rolling bearing and a second rib 32a located on the axially outer side of the rolling bearing. A middle spacer 4 is arranged between the two inner ring members 2 in the axial direction.

The outer ring member 1, the cage 2, and the two inner ring members 3a are coaxially and radially nested in this order such that a row of tapered rollers held by one cage 2 can be arranged between the outer ring member 1 and each inner ring member 3 a.

The two holders 2 according to the present embodiment are configured as window holders. The cage 2 has two annular portions distributed in the axial direction, namely a first annular portion 21 located axially inside the rolling bearing and a second annular portion 23 located axially outside the rolling bearing. The cage 2 also has a plurality of beam portions 22 connecting the first annular portion 21 and the second annular portion 23. The plurality of beam portions 22 are evenly distributed in the circumferential direction so that the first annular portion 21 and the second annular portion 23 cooperate with two adjacent beam portions 22 to define a pocket for holding the tapered roller. The cage 2 is here, for example, a metal cage.

In the present embodiment, the rolling bearing is arranged in two rows of the tapered rollers in an O-ring configuration such that the load action center of each row of the tapered rollers is located outside the axial center line of the rolling bearing. Here, the raceway space formed by the outer ring member 1 and each inner ring member 3a for accommodating one row of tapered rollers extends substantially along the tapered surface formed by the rotation axis of each tapered roller in the corresponding row.

The rolling bearing is lubricated by grease in this embodiment. The grease is injected through the through hole 11 of the outer ring member 1, so that the grease is located in the axially intermediate region of the rolling bearing, particularly between the two cages 2, at the initial stage of completion of assembly or completion of maintenance.

As shown in fig. 1, the anti-adhesion coating 5 is applied at the first annular portion 21 of each cage 2. In the present embodiment, the anti-adhesion coating 5 is applied to the radially outer side, the radially inner side, and the axial end side toward the other cage 2 of the first annular portion 21. Here, the release coating 5 is composed of a material containing polytetrafluoroethylene. The material comprising polytetrafluoroethylene has a lower coefficient of friction against grease than the material from which the cage 2 is constructed (e.g., metal in this embodiment or plastic in other embodiments). Friction between the grease and the first annular portion 21 of the cage 2 can thereby be advantageously reduced. In particular, in the case of a small distance between the first annular portion 21 of the cage 2 with respect to the first rib 31a of the inner ring member 3a and the outer ring member 1, the grease accumulated in the axially intermediate region of the rolling bearing can more easily flow through the first annular portions 21 of the two cages 2 in a larger amount by means of the anti-stick coating 5 during the operation of the rolling bearing, so that more of the grease enters the raceway spaces of the tapered rollers and the raceways are better lubricated

In the present embodiment, the inner peripheral surface of the first annular portion 21 extends substantially in the axial direction of the rolling bearing, and the anti-sticking coating 5 has a varying thickness at the inner peripheral surface of the first annular portion 21, so that the inner peripheral surface of the anti-sticking coating 5 finally formed at the first annular portion 21 can have an inner diameter that gradually increases from the axially inner side toward the axially outer side of the rolling bearing, so that this inclined design matches the raceway space where the tapered rollers are arranged in an O-type configuration.

In the present embodiment, the outer peripheral surface of the first annular portion 21 is inclined to the axial configuration of the rolling bearing, and the anti-sticking coating 5 has substantially the same thickness at the outer peripheral surface of the first annular portion 21, so that the outer peripheral surface of the anti-sticking coating 5 finally formed at the first annular portion 21 can have an outer diameter gradually increasing from the axially inner side toward the axially outer side of the rolling bearing, so that this inclined design matches the raceway space where the tapered rollers are arranged in the O-type configuration.

By the arrangement of the anti-sticking coating 5, particularly the configuration matching the raceway space of the tapered rollers at the first annular portion 21, the accumulation of grease in the axially intermediate region of the rolling bearing can be effectively reduced, whereby the temperature rise of the rolling bearing due to the accumulated grease and the large friction of the cage 2 during operation can be suppressed, and the service life of the rolling bearing can be extended. The rolling bearing can be adapted to the operating conditions of higher-speed rotation, and can particularly meet the increasing requirements of high-speed trains. In addition, the maintenance interval time of the rolling bearing can be prolonged by properly increasing the total amount of grease added in a single maintenance on the premise of ensuring the required service life of the bearing and/or meeting the actual rotating speed requirement.

Furthermore, an annular groove 12 is formed in the radially inner axial center region of the outer ring member 1. The annular groove 12 is connected to the through-hole 11 for injecting the lubricant. This enables more lubricant to be stored by means of the annular groove 12.

Furthermore, the radially outer side of the intermediate collar 4 is configured with an annular groove 41. This makes it possible to store more lubricant by means of the annular groove 41 and facilitates the introduction of more grease into the raceway space of the tapered rollers during the movement of the rolling bearing.

Fig. 2 shows a perspective half-sectional view of a rolling bearing according to a second preferred embodiment of the invention. The rolling bearing according to the present embodiment is similar to the rolling bearing according to the first preferred embodiment, and differs therefrom mainly in the structure of the first rib of the inner ring member.

As shown in fig. 2, in the second preferred embodiment, the first ribs 31b of the two inner race members 3b are configured with inclined surfaces that connect the outer peripheral surfaces and the axial end surfaces of the ribs. The ramp surface thus constructed is capable of guiding the grease directly into the raceway space of the tapered roller on the one hand, and is capable of guiding the grease to the anti-stick coating 5 of the cage 2 and then into the tapered roller raceway space through the anti-stick coating 5 on the other hand.

Fig. 3 shows a three-dimensional, half-sectional view of a rolling bearing according to a third preferred embodiment of the invention. The rolling bearing according to the present embodiment is similar to the rolling bearing according to the first preferred embodiment, and differs therefrom mainly in the structure of the first rib of the inner ring member.

Fig. 4 shows a perspective view of an inner ring of a rolling bearing according to a third preferred embodiment of the invention. Fig. 5 is a partially enlarged view of fig. 4. As can be seen in connection with fig. 3 to 5, the first ribs 31c of the two inner ring members 3c are configured with notches 33c distributed in the circumferential direction. Each notch 33c opens toward the axial end side facing away from the second bead 32c and opens toward the radial outside. The thus configured groove 33c is capable of guiding grease directly into the raceway space of the tapered roller on the one hand, and is capable of guiding grease to the anti-stick coating 5 of the cage 2 on the other hand, and then is guided into the tapered roller raceway space through the anti-stick coating 5. Further, the provision of the notch 33c also enables an increase in the grease storage capacity of the rolling bearing.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

1 outer ring component

11 oil filler hole

12 grooves

2 holding rack

21 first annular portion

22 Beam section

23 second annular portion

3a inner ring member

31a rib, first rib

32a flange, second flange

3b inner ring component

31b flange, first flange

3c inner ring component

31c rib, first rib

32c flange, second flange

33c notch

4 middle partition ring

41 annular groove

5 anti-adhesive coating

Claims (10)

1. Rolling bearing, comprising:

two rows of rolling bodies;

an outer ring configured with inner races for the rolling bodies;

an inner ring configured with an outer raceway for the rolling elements; and

two cages (2), which two cages (2) are arranged axially side by side between the outer ring and the inner ring and are each used for one of the two rows of rolling bodies,

characterized in that an axial end (21) of the cage (2) which is located axially inside the rolling bearing is coated with an anti-adhesive coating (5), wherein the anti-adhesive coating (5) consists of a material which has a lower coefficient of friction with respect to a lubricant used for the rolling bearing than the material from which the cage (2) is made.

2. Rolling bearing according to claim 1, wherein the anti-sticking coating (5) comprises polytetrafluoroethylene.

3. Rolling bearing according to claim 1, wherein the cage (2) has two annular portions (21, 23) distributed in the axial direction and a plurality of beam portions (22) connecting the two annular portions (21, 23), wherein the annular portion (21) of the cage (2) located axially inside the rolling bearing is coated with the anti-sticking coating (5).

4. Rolling bearing according to claim 1, wherein the axial end (21) and/or the anti-sticking coating (5) is configured such that an inner circumferential surface and/or an outer circumferential surface of the anti-sticking coating (5) formed at the axial end (21) extends in a direction oblique to an axial direction of the rolling bearing.

5. Rolling bearing according to claim 1, wherein the cage (2) is coated on all sides with said anti-sticking coating.

6. Rolling bearing according to claim 1, wherein the inner ring comprises two inner ring members (3a, 3b, 3c) arranged axially side by side, wherein a middle spacer ring (4) is arranged axially between the two inner ring members (3a, 3b, 3 c).

7. Rolling bearing according to claim 6, wherein each of the two inner ring members (3b) is configured with a rib (31b) adjacent to the other inner ring member (3b), the rib (31b) being configured with a slope connecting an outer circumferential surface and an axial end surface of the rib (31 b).

8. Rolling bearing according to claim 6, wherein each inner ring member (3c) of the two inner ring members (3c) is configured with a rib (31c) close to the other inner ring member (3c), said rib (31c) being configured with notches (33c) distributed in the circumferential direction.

9. Rolling bearing according to claim 6, wherein the radially outer side of the intermediate ring (4) is configured with an annular groove (41).

10. Rolling bearing according to claim 1, wherein the outer ring (1) consists of a separate outer ring member (1), wherein a groove (12) is formed in a radially inner, axially intermediate region of the outer ring member (1).

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