CN110785571B

CN110785571B - Rolling bearing with lubricant

Info

Publication number: CN110785571B
Application number: CN201880041411.1A
Authority: CN
Inventors: 米歇尔·保施; 斯文·克劳斯; 沃尔特·霍尔韦格
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2017-06-21
Filing date: 2018-04-16
Publication date: 2021-07-20
Anticipated expiration: 2038-04-16
Also published as: JP2020528524A; DE102017113704A1; CN110785571A; JP6884236B2; WO2018233746A1; EP3642500A1

Abstract

The invention relates to a rolling bearing (1) having an inner ring (2) and an outer ring (3) which are formed from a ring material, wherein the inner ring (2) has raceways (4, 5) for guiding rolling bodies (6) on the outer circumferential surface and the outer ring (3) has raceways (4, 5) for guiding the rolling bodies (6) on the inner circumferential surface, wherein the rolling bodies (6) roll on the respective raceways (4, 5), and wherein a lubricant (7) is arranged spatially between the inner ring (2) and the outer ring (3), which lubricant at least contacts the inner ring (2) and/or the outer ring (3), wherein the ring material comprises at least the following alloy components: iron, carbon, chromium, molybdenum and vanadium. According to the invention, the ratio of the weight fractions of chromium, molybdenum and vanadium is 1 to at least 0.8 and at most 1.5 to at least 0.5 and at most 1.3.

Description

Rolling bearing with lubricant

Technical Field

The invention relates to a rolling bearing having an inner ring, an outer ring, rolling bodies spatially arranged between the inner ring and the outer ring, and a lubricant for lubricating and cooling the rolling contacts between the rolling bodies and the respective bearing rings.

Background

One of the important failure mechanisms, particularly for rolling bearings supporting fast rotating shafts, is the short service life of the lubricant. Insufficient lubrication in the rolling contact between the rolling bodies and the respective bearing ring is caused in particular by frictional overloading and high operating temperatures. The mechanism that promotes inadequate lubrication is, for example, a high spin-to-roll ratio, which leads in particular to a higher slip between the rolling elements and the respective bearing ring. Thereby altering the viscosity of the lubricant, particularly negatively. In addition, aging of the lubricant results in the lubricant becoming harder and harder. Since the lubricant in the rolling bearing is generally pressed into a region which is as undisturbed as possible by the rolling element groups, the output tendency of the base oil from the lubricant to the rolling contact decreases when the lubricant hardens. This results in insufficient lubrication depending on the oil output. These two causes of inadequate lubrication often occur simultaneously and often lead to rapid, self-reinforcing destruction processes of the lubricant or to a locking of the rolling bearing.

Fast rotation means a rotation speed of more than one million revolutions per minute, where n x dm is applicable, where n is the rotation speed and dm is the average bearing diameter. For example, when the average bearing diameter is 100mm, the rapid rotation is understood to be 10000 revolutions/minute.

Disclosure of Invention

The object of the present invention is to improve rolling bearings and in particular to increase the service life of the lubricant contained therein.

This object is achieved by the rolling bearing according to the invention. Preferred or advantageous embodiments of the invention result from the following description and the accompanying drawings.

The rolling bearing according to the invention comprises an inner ring and an outer ring which are formed from a ring material, wherein the inner ring has raceways for guiding the rolling elements on the outer circumferential surface and the outer ring has raceways for guiding the rolling elements on the inner circumferential surface, wherein the rolling elements roll on the respective raceways, and wherein a lubricant is arranged spatially between the inner ring and the outer ring, which lubricant at least contacts the inner ring and/or the outer ring, wherein the ring material comprises at least the following alloy components: iron, carbon, chromium, molybdenum and vanadium, and wherein the ratio of the weight fractions of chromium, molybdenum and vanadium is 1 to at least 0.8 up to 1.5 to at least 0.5 up to 1.3. The ratio of the molybdenum to the vanadium is in particular at least 1 to at most 3.

In other words, the weight ratio of Cr to Mo to V is 1:0.8 to 1.5:0.5 to 1.3. Further, the weight fraction of Mo: the weight fraction of V was 1: 3. The service life of the lubricant in the rolling bearing, in particular in the rapidly rotating spindle bearing, can thus be increased by controlling the oxidation of the lubricant by means of the weight proportion of chromium, molybdenum or vanadium, so that the oil flow from the lubricant to the raceways on the inner ring or outer ring is controlled in order to lubricate the rolling contact.

Oxidation is understood to increase the flowability of the lubricant or the base oil contained therein. Oxidation of the lubricant is generally an undesirable process because oxidation of the lubricant results in more rapid oil evolution of the lubricant. By oil bleeding is understood that the base oil escapes from the lubricant. The oxidation of the lubricant is controlled by a suitable proportioning of the chromium, vanadium and molybdenum in the ring material, wherein hardening is avoided and at the same time a slow and targeted oil bleeding of the lubricant is achieved. To this end, the lubricant contacts the ring material.

Preferably, the ratio of the weight fractions of chromium, molybdenum and vanadium is 1 to at least 1.1 and at most 1.3 to at least 0.65 and at most 0.85. In other words, the weight ratio of Cr to Mo to V is 1:1.1 to 1.3:0.65 to 0.85. The preferred ratio of the weight fractions of chromium, molybdenum and vanadium further increases the service life of the lubricant.

Preferably, the ratio of the weight fractions of molybdenum and vanadium is at least 1.25 and at most 1.8. Thus, the weight fraction of Mo: the weight fraction of V is 1.25: 1.8. The preferred weight ratio of molybdenum to vanadium further increases the service life of the lubricant.

Furthermore, the rolling bearing is preferably made of a ceramic material or a ring material. By combining the inner ring and the outer ring formed from the ring material according to the invention with the rolling elements made from a ceramic material, the need for lubricants is reduced, since the metal-ceramic pairing forms a smaller contact surface in the same geometry and load than the metal-metal pairing. Furthermore, the viscous and abrasive wear processes are suppressed by the metal-ceramic material pairing.

The present invention includes the technical teaching that the lubricant includes a polyalphaolefin or ester oil as a base oil. Preferably, the lubricant comprises polyaryl urea, lithium complex soap or barium complex soap as a thickener.

According to a preferred embodiment, the lubricant is a spindle bearing grease with specification KEHC3K-50 according to DIN 51825. The temperature range used is from-50 ℃ to 120 ℃ in accordance with DIN 51825. The viscosity of the base oil at 40 ℃ is 22mm according to DIN 51562-1²And s. Furthermore, the working penetration (1/10mm) is 220 to 250 according to DIN ISO 2137. The NLGI scale to DIN 51818 is 3. The dropping point according to DIN ISO 2176 is above 250 ℃.

According to a further preferred embodiment, the lubricant is a spindle bearing grease with the specification KPHC2/3K-40 according to DIN 51825. The temperature range used is from-40 ℃ to 120 ℃ in accordance with DIN 51825. The viscosity of the base oil at 40 ℃ is 25mm according to DIN 51562-1²And s. Furthermore, the working penetration (1/10mm) is 220 to 250 according to DIN ISO 2137. The NLGI scale to DIN 51818 is 2 or 3. The dropping point according to DIN ISO 2176 is above 220 ℃.

Drawings

The further measures improving the invention are subsequently shown in detail together with the description of the preferred embodiments of the invention with the aid of the drawing. Here:

fig. 1 shows a schematic perspective view of a rolling bearing according to the invention; and

fig. 2 shows a schematic partial sectional view of a bearing arrangement with a rolling bearing according to fig. 1 and with a shaft.

Detailed Description

According to fig. 1, a rolling bearing 1 according to the invention for a machine tool not shown here comprises an inner ring 2 and an outer ring 3 and balls as rolling bodies 6 arranged radially between the inner ring 2 and the outer ring 3. The rolling bodies 6 are guided by a cage 8. The rolling bearing 1 is designed as a deep groove ball bearing.

In fig. 2, the rolling bearing 1 of fig. 1 supports a shaft 9. The shaft 9 is currently configured as a spindle of a machine tool. The inner ring 2 has a raceway 4 for guiding rolling elements 6 on the outer circumferential surface. The outer ring 3 also has a raceway 5 for guiding the rolling elements 6 on the inner peripheral surface. Rolling bodies 6 roll between the inner ring 2 and the outer ring 3 on the respective raceways 4, 5, wherein the rolling bodies 6 are constructed from a ceramic material. Furthermore, a lubricant 7 is spatially arranged between the inner ring 2 and the outer ring 3 for lubricating and cooling the rolling contacts between the inner ring 2 and the rolling bodies 6 and between the outer ring 3 and the rolling bodies 6. The lubricant 7 contacts not only the inner ring 2 and the outer ring 3 but also the rolling elements 6.

The inner ring 2 and the outer ring 3 are constructed from a ring material, wherein the ring material comprises at least the following alloy constituents: iron, carbon, chromium, molybdenum and vanadium. The ratio of the weight portions of chromium, molybdenum and vanadium is 1 to at least 0.8 and at most 1.5 to at least 0.5 and at most 1.3. The weight ratio of the molybdenum to the vanadium is at least 1 to at most 3. The lubricant 7 includes polyalphaolefin as a base oil and polyaryl urea as a thickener. The oxidation of the lubricant 7 is controlled by a suitable proportioning of the weight proportions of chromium, vanadium and molybdenum in the ring material, hardening being avoided and at the same time a suitable flow of the base oil from the lubricant 7 being achieved. This prolongs the service life of the lubricant 7 in the rolling bearing 1.

List of reference numerals

1 rolling bearing

2 inner ring

3 outer ring

4 raceway

5 raceway

6 ball

7 lubricating agent

8 holding rack

9 shaft

Claims

1. Rolling bearing (1) having an inner ring (2) and an outer ring (3) which are formed from a ring material, wherein the inner ring (2) has raceways (4, 5) for guiding rolling bodies (6) on the outer circumferential surface and the outer ring (3) has raceways (4, 5) for guiding the rolling bodies (6) on the inner circumferential surface, wherein the rolling bodies (6) roll on the respective raceways (4, 5), and wherein a lubricant (7) is arranged spatially between the inner ring (2) and the outer ring (3), which lubricant at least contacts the inner ring (2) and/or the outer ring (3), wherein the ring material comprises at least the following alloy components: iron, carbon, chromium, molybdenum and vanadium, characterized in that the ratio of the weight fractions of chromium, molybdenum and vanadium is 1 to at least 1.1 and at most 1.3 and at least 0.65 and at most 0.85.

2. Rolling bearing (1) according to claim 1, characterized in that the ratio of the weight fractions of molybdenum, vanadium is at least 1 and at most 3.

3. Rolling bearing (1) according to claim 1 or 2, characterized in that the ratio of the weight fractions of molybdenum, vanadium is at least 1.25 and at most 1.8.

4. Rolling bearing (1) according to claim 1 or 2, characterized in that the rolling bodies (6) are constructed from a ceramic material or the ring material.

5. Rolling bearing (1) according to claim 1 or 2, wherein the lubricant (7) comprises a polyalphaolefin or an ester oil as a base oil.

6. Rolling bearing (1) according to claim 1 or 2, characterized in that the lubricant (7) comprises polyaryl urea, lithium complex soap or barium complex soap as thickener.

7. Use of a rolling bearing (1) according to any of claims 1 to 6 for supporting a main shaft or for supporting a compressor shaft or for supporting a rotor shaft.