DE102018123505A1 - Slewing ring and method for manufacturing a slewing ring - Google Patents

Abstract

The invention relates to a large roller bearing ring (1), namely an inner ring (1a) or an outer ring (1b) of a large roller bearing, with an outer diameter (2) of at least 0.5 m made of a steel alloy, comprising 0.45 to 0.55 wt % Carbon, 0.20 to 0.40% by weight silicon, 1.30 to 1.60% by weight manganese, 1.80 to 2.10% by weight chromium, 0.50 to 1, 20% by weight of nickel and 0.10 to 0.40% by weight of molybdenum. The invention further relates to a method for producing a large roller bearing ring (1) and the use of a steel alloy for producing a large roller bearing ring 1.

Description

The invention relates to a large roller bearing ring, namely an inner ring or an outer ring of a large roller bearing. Furthermore, the invention also relates to a method for producing a large roller bearing ring and the use of a steel alloy for producing a large roller bearing ring.

Large roller bearings have at least one outer ring, one inner ring and rolling elements arranged spatially between them and are well known from the prior art. Large roller bearings are usually heavily loaded and have a comparatively large diameter of at least 0.5 m up to 20 m. Areas of application for large roller bearings are, for example, cranes, excavators, shaft drilling systems and tunnel boring machines.

For example, the DE 20 2011 051 680 U1 a large roller bearing with an outer ring and an inner ring, wherein the outer ring and the inner ring are arranged rotatable relative to each other with the interposition of rolling elements.

As a rule, large roller bearing rings are made from the steel alloys 42CrMo4 and 50CrMo4 and then induction hardened at the surface.

The object of the present invention is to further develop a large roller bearing ring and a method for producing a large roller bearing ring, and in particular to reduce the production costs and to improve the material properties of the large roller bearing ring. The object is achieved by the subject matter of claims 1 and 8. Preferred embodiments can be found in the dependent claims.

A large roller bearing ring according to the invention, namely an inner ring or an outer ring of a large roller bearing, with an outer diameter of at least 0.5 m is made of a steel alloy comprising 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight. -% silicon, 1.30 to 1.60% by weight manganese, 1.80 to 2.10% by weight chromium, 0.50 to 1.20% by weight nickel, and 0.10 to 0, 40 wt .-% molybdenum produced.

The indication “% by weight” stands for percent by weight and serves as a content variable, ie as a physico-chemical variable for the quantitative description of the composition of the steel alloy.

The carbon content of the steel alloy of 0.45 to 0.55% by weight essentially serves to achieve the necessary hardness for the rolling resistance of the large roller bearing ring. In particular, the steel alloy has more than 0.46% by weight of carbon. The silicon content of the steel alloy from 0.20 to 0.40% by weight serves to increase the thermal stability of the slewing ring. The manganese content of the steel alloy of 1.30 to 1.60% by weight also serves to increase the hardenability and toughness of the large roller bearing ring. The chromium content of the steel alloy of 1.80 to 2.10% by weight serves to increase the hardenability of the slewing ring. The nickel content of the steel alloy from 0.50 to 1.20% by weight serves to increase the toughness of the slewing ring. The molybdenum content of the steel alloy of 0.10 to 0.40% by weight also serves to increase the hardenability and toughness.

The alloy composition of the steel alloy according to the invention adjusts the properties of the large roller bearing ring that are necessary in connection with a coordinated heat treatment and enables a reduction in the manufacturing costs in the entire manufacturing process. Manganese, chrome and molybdenum increase the hardenability of the steel alloy. Furthermore, the molybdenum content of the steel alloy lowers segregations in the steel alloy from 0.10 to 0.40% by weight and thus increases the homogeneity of the steel alloy. In addition to hardenability, silicon also increases the temper resistance of the steel alloy. Nickel increases the hardenability and basic strength of the steel alloy through mixed crystal hardening.

The large roller bearing ring preferably has an outer diameter of at least 0.7 m to at most 5 m. In particular, the outer diameter of the large roller bearing ring is 1 m to 3.5 m.

The large roller bearing ring preferably has a radial wall thickness of at least 0.1 m to at most 0.3 m. In particular, the radial wall thickness of the large roller bearing ring is 0.15 m to 0.25 m.

The large roller bearing ring also preferably has an inductively hardened edge layer. In other words, the slewing ring is at least partially or completely inductively hardened at the surface. Induction hardening enables the hardening of specific surface areas of the slewing ring. After the surface areas have been inductively heated, they can be quenched by oil or oil mist or water or water mist. Alternatively, the quenching takes place automatically by the heat flowing away into the rest of the unheated inner region of the large roller bearing ring.

In particular, the inductively hardened surface layer is at least 2 mm to at most 12 mm. The boundary layer can be measured by means of light microscopy or by electron microscopy.

The invention includes the technical teaching that the inductively hardened surface layer has a hardness of at least 650 HV. The hardness of the surface layer is therefore measured using the Vickers method. In particular, the hardness value of the Vickers hardness is at least 650 HV with a test force of 10 kilopond and a loading time 15 Seconds.

The steel alloy preferably has a notched bar impact bending work of at least 27 J at -40 ° C. The notched bar impact bending work of at least 27 joules at -40 ° C is essentially set by the alloy content of the nickel in the steel alloy. The notched bar impact bending work is determined in the notched bar impact test and serves as a measure of the resistance of a material to sudden dynamic stress.

According to a method according to the invention for producing a large roller bearing ring, namely an inner ring or an outer ring of a large roller bearing, with an outer diameter of at least 0.5 m, the large roller bearing ring is first made of a steel alloy comprising 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight silicon, 1.30 to 1.60% by weight manganese, 1.80 to 2.10% by weight chromium, 0.50 to 1.20% by weight Nickel, as well as 0.10 to 0.40 wt .-% molybdenum, formed and then at least hardened and tempered.

The hardening and tempering of the hardened steel material is a heat treatment that is used to adjust the properties of the slewing ring, in particular to adjust the slewing ring for downstream machining processes. The slewing ring is homogenized by the heat treatment.

The large roller bearing ring is preferably inductively hardened at the surface after tempering. The inductive surface hardening of the slewing ring lowers the manufacturing costs compared to case hardened slewing rings. However, workpieces that are intended for induction hardening must have a more homogeneous structure compared to workpieces that should be case hardened in order to form a homogeneous macroscopic stress state in the boundary layer zone and thereby reduce the risk of cracks due to inhomogeneities. The large roller bearing ring is further preferably mechanically reworked after the inductive surface hardening, in particular hard turned and / or hard ground and / or polished. At least one raceway, which is provided for receiving rolling elements on the slewing ring, is polished in order to increase the load-bearing capacity of the slewing bearing.

According to the invention, the use of a steel alloy comprising 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight of silicon, 1.30 to 1.60% by weight of manganese, 1.80 up to 2.10% by weight of chromium, 0.50 to 1.20% by weight of nickel and 0.10 to 0.40% by weight of molybdenum for the production of a large roller bearing ring with an outside diameter of at least 0.5 m . The steel alloy is preferably intended to be inductively hardened at the surface.

• 1 eine stark vereinfachte schematische Schnittdarstellung eines Großwälzlagerrings gemäß einer ersten Ausführungsform,
• 2 eine stark vereinfachte schematische Schnittdarstellung eines Großwälzlagerrings gemäß einer zweiten Ausführungsform, und
• 3 eine stark vereinfachte schematische Schnittdarstellung eines Großwälzlagerrings gemäß einer dritten Ausführungsform.

Further measures improving the invention are shown below together with the description of three preferred exemplary embodiments of the invention with reference to the figures. It shows

• 1 1 shows a greatly simplified schematic sectional illustration of a large roller bearing ring according to a first embodiment,
• 2nd a greatly simplified schematic sectional view of a slewing ring according to a second embodiment, and
• 3rd a greatly simplified schematic sectional view of a slewing ring according to a third embodiment.

The 1 , 2nd and 3rd show a respective large roller bearing ring according to the invention 1 a slewing bearing, the respective slewing ring 1 an outer diameter 2nd of over 0.5 m, namely 1 m. Furthermore, the respective large roller bearing ring 1 made of a steel alloy, the steel alloy having an alloy composition of 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight of silicon, 1.30 to 1.60% by weight of manganese, 1.80 to 2.10 wt .-% chromium, 0.50 to 1.20 wt .-% nickel, and 0.10 to 0.40 wt .-% molybdenum.

The advantage of this alloy composition is that the critical quenching rate to achieve the necessary hardness in the heat treatment is reduced, which leads to a better tempering result. This results in better structural homogeneity and less warpage, since quenching can be carried out more mildly. This also reduces other straightening processes and machining allowances.

A radial wall thickness 3rd of the respective slewing ring 1 is 0.2 m. All embodiments of the slewing ring 1 have an induction hardened surface layer 4th on. The induction hardened surface layer 4th is 8 mm and has a hardness of at least 650 HV.

According to 1 is the boundary layer 4th on the entire surface of the slewing ring 1 educated. The slewing ring 1 is an inner ring in the present case 1a of the large roller bearing, with - not shown here - rolling elements of the large roller bearing are provided on an outer peripheral surface of the inner ring 1a come to rest and radially between the inner ring 1a and roll - an outer ring - not shown here.

To 2nd is the boundary layer 4th on an outer peripheral surface of the slewing ring 1 educated. The slewing ring 1 is an inner ring in the present case 1a of the large roller bearing, wherein - not shown here - rolling elements of the large roller bearing are provided on an outer peripheral surface of the inner ring 1a come to rest and radially between the inner ring 1a and roll - an outer ring - not shown here.

In 3rd is the boundary layer 4th on an inner peripheral surface of the slewing ring 1 educated. The slewing ring 1 is an outer ring in the present case 1b of the large roller bearing, wherein - not shown here - rolling elements of the large roller bearing are provided on an inner peripheral surface of the outer ring 1b come to rest and radially between the outer ring 1b and to roll off an inner ring (not shown here).

Reference list

1

Slewing ring

1a

Inner ring

1b

Outer ring

2nd

outer diameter

3rd

Wall thickness

4th

Boundary layer

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202011051680 U1 [0003]

Claims (10)

Large roller bearing ring (1), namely an inner ring (1a) or an outer ring (1b) of a large roller bearing, with an outer diameter (2) of at least 0.5 m made of a steel alloy, comprising 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight of silicon, 1.30 to 1.60% by weight of manganese, 1.80 to 2.10% by weight of chromium, 0.50 to 1.20 wt .-% nickel, and 0.10 to 0.40 wt% molybdenum. Slewing ring (1) after Claim 1 , characterized by an outer diameter (2) of at least 0.7 m to at most 5 m. Large roller bearing ring (1) according to one of the preceding claims, characterized by a radial wall thickness (3) of at least 0.1 m to at most 0.3 m. Large roller bearing ring (1) according to one of the preceding claims, characterized by an inductively hardened edge layer (4). Slewing ring (1) after Claim 4 , characterized in that the inductively hardened edge layer (4) is at least 2 mm to at most 12 mm. Slewing ring (1) according to one of the Claims 4 or 5 , characterized in that the inductively hardened edge layer (4) has a hardness of at least 650 HV. Large roller bearing ring (1) according to one of the preceding claims, characterized in that the steel alloy has a notched bar impact bending work of at least 27 J at -40 ° C. Method for producing a large roller bearing ring (1), namely an inner ring (1a) or an outer ring (1b) of a large roller bearing, with an outer diameter (2) of at least 0.5 m, first comprising the large roller bearing ring (1) made of a steel alloy 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight of silicon, 1.30 to 1.60% by weight of manganese, 1.80 to 2.10% by weight of chromium, 0.50 to 1.20 wt .-% nickel, and 0.10 to 0.40% by weight of molybdenum, trained and then at least hardened and tempered. Procedure according to Claim 8 , characterized in that the large roller bearing ring (1) is inductively hardened at the surface after tempering and then mechanically refinished. Use of a steel alloy comprising 0.45 to 0.55% by weight of carbon, 0.20 to 0.40% by weight of silicon, 1.30 to 1.60% by weight of manganese, 1.80 to 2.10% by weight of chromium, 0.50 to 1.20 wt .-% nickel, and 0.10 to 0.40% by weight of molybdenum for producing a large roller bearing ring (1) with an outer diameter of at least 0.5 m.

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