Rolling surface element of rolling element bearing assembly and method for repairing the same

Abstract

A rolling surface element of a rolling element bearing assembly includes a rolling raceway on which the rolling element is configured to roll and a cavity located in the area of ​​its rolling raceway, the opening surface of the cavity being less than 25% of the total raceway surface, wherein an insert that helps to form the rolling raceway is inserted into the cavity in a press-fit manner; and a method for repairing a rolling surface element of a rolling element bearing assembly, the rolling surface element includes a rolling raceway on which the rolling element is configured to roll, the method comprising the following steps: identifying at least one damaged or no longer flawless area of ​​the rolling raceway, machining a cavity including the identified area outwardly from the rolling raceway, inserting an insert suitable for the cavity into the cavity in a press-fit manner, wherein the insert is constructed so that it protrudes beyond the rolling raceway around the insert, and corroding the protruding area of ​​the insert to remanufacture the rolling raceway.

Description

Technical Field

[0001] The present invention relates to a rolled-on-surface element (rolled-on-surface element / surface element on which rollers roll) of a rolling element bearing assembly (rolling bearing assembly) and a method for repairing a rolling-on-surface element. Background Art

[0002] Depending on the loads actually occurring during operation of the rolling element bearing, a rolling element bearing ( / rolling bearing) reaches the end of its service life sooner or later. By monitoring the rolling element bearing with condition detection sensors, the impending end of life can be predicted in good time, for example due to impending damage. Alternatively, the rolling element bearing without such sensors is operated until damage occurs or until the calculated end of service life. In this case, the complete rolling element bearing is usually replaced by a new one. Summary of the Invention

[0003] The object of the present invention is to provide a rolling surface element of a rolling element bearing assembly and a method for repairing a rolling surface element to extend its service life.

[0004] This object is achieved by the solutions of claims 1 and 6. Advantageous embodiments are described in the dependent claims.

[0005] The present invention is based in particular on the recognition that replacing a rolling element bearing that needs to be replaced with a new, complete rolling element bearing is not very sustainable ( / not very rationally utilized), in particular for large and expensive rolling element bearings, and in many cases is absolutely unnecessary, but rather such a repair is feasible.

[0006] Rolling element bearings typically include an outer rolling-on-surface element, often configured as an outer ring of the bearing, an inner rolling-on-surface element, often configured as an inner ring of the bearing, and at least one row of rolling elements, arranged to roll on the rolling raceways (or roller raceways) of the inner and outer rolling-on-surface elements and disposed between the two elements. The rolling elements may be housed in a cage that prevents contact between the rolling elements. Furthermore, the space between the outer and inner rolling-on-surface elements housing the rolling elements may be sealed, for example, by a sealing disk or cover disk disposed on the outer rolling-on-surface element. A lubricant, such as a lubricating paste, may be present in this space. Typically, the outer and inner rolling-on-surface elements are made of steel, in particular, hardened rolling-element bearing steel; however, the steel may also be case-hardened steel. The same applies to the rolling elements, which may also be formed from a ceramic material. The cage is constructed in one piece or in multiple pieces and is usually made of steel, in particular steel or brass or plastic.

[0007] The method here comprises the following steps. First, a repairable rolling element bearing is removed from its mounting environment and disassembled at least enough to enable free access to the rolling tracks of the bearing inner ring and / or the bearing outer ring. Here, at least the rolling tracks, areas with contaminants and lubricant adhering to the rolling tracks, and areas adjacent to the rolling tracks are cleaned. Then, rolling areas that may be damaged or can no longer be used (or are no longer flawless) are identified. This can start with a simple visual inspection to find signs of damage (e.g., areas of the rolling tracks where crack formation or fissures occur), optionally using ultrasound, stray current and / or other suitable testing methods.

[0008] After the above-mentioned tests have been used to identify the area of ​​the bearing raceway showing signs of damage, repair is only considered if, in particular, one or several separate, spatially connected areas are present, forming only a portion of the bearing raceway. For example, repair is possible if the damaged area is demarcable on the bearing raceway by a single circular (or annular) area. For example, large crack networks cannot be repaired, and the bearing ring must be replaced with a new one.

[0009] However, if a repairable area exists, such as a circularly delimitable area, a cylindrical cavity several millimeters deep (e.g., down to 5 to 10 mm deep) is machined into the rolling track in this circular area. The open surface of the cavity can be less than 25% of the total rolling track surface. This machining can be accomplished, for example, using a mobile CNC-controlled milling and / or grinding machine. Alternatively, a spark erosion machine and / or any other material ablation method can be used. The cavity diameter is typically selected based on permanently fixed diameter grades (e.g., in 10 mm steps), which advantageously allows the use of corresponding prefabricated inserts, so to speak, standard inserts. Alternatively, the cavity geometry can be selected to enable the use of prefabricated, prefabricated inserts that are staggered according to size. The inserts are made of the same material as the bearing rings or a material exhibiting the same or similar properties. The diameters of the insert and the cavity are formed relative to one another at the same temperature with a definable fit, in particular a definable press fit. Alternatively, the cavity can be cylindrical, in particular cylindrical, and the insert can be correspondingly disc-shaped, in particular disc-shaped, and / or the insert can be inserted from the side on which the rolling track is to be fed.

[0010] The selected insert is then provided with a thermally conductive paste on the side of the selected insert that is intended to abut the base of the cavity. In particular, the thermally conductive paste improves the contact between the insert and the base of the cavity, thereby removing (dissipating) heat generated by rolling contact in the region of the insert in the bearing rings during subsequent operation of the rolling element bearing. In other embodiments, the thermally conductive paste can also be omitted.

[0011] The insert is then cooled significantly. For example, this cooling can be achieved with the aid of liquid nitrogen at a temperature of -196°C. Of course, cooling can also be achieved with the aid of other media and / or other suitable methods. Simultaneously, the bearing ring to be repaired is heated, at least in the region of the cavity. This can be achieved using an induction heater and / or any other suitable heating device and / or method. Ultimately, cooling and heating must be coordinated with one another so that the disc insert can be inserted into the circular, cylindrical cavity of the raceway ring, thanks to the press-fit diameter design of the insert and cavity relative to one another. Finally, the cooled insert is inserted into the heated cavity of the bearing ring and pressed against it under a defined pressure.

[0012] Since the insert is designed relative to its height in comparison with the area surrounding the insert for the rolling track, the used insert protrudes beyond the area surrounding the insert for the rolling track, after the temperature between the insert and the bearing ring has equalized, the original rolling track can be remanufactured by machining the insert in a corresponding material-ablating manner by milling, grinding and / or honing. For this purpose, a mobile CNC milling, grinding and / or honing machine can be used.

[0013] The bearing rings are then cleaned and the rolling element bearing is reassembled with the repaired bearing rings, optionally with fresh lubricant. The repaired rolling element bearing is then reinstalled in its installation environment. If the rolling element bearing is not provided with a condition detection sensor, the rolling element bearing or its installation environment will be equipped with such a condition detection sensor (only temporarily) to verify the flawless repair result in the installation environment at least during the test run. This can be achieved, for example, based on an assessment of vibrations, oscillations, temperature and / or the like captured by the condition detection sensor. Of course, alternatively and / or additionally, such a test run can also be carried out outside the intended installation environment of the rolling element bearing.

[0014] As an alternative, the cavity can also be formed as a through-hole through the rolling surface element, in particular with a frustoconical shape, wherein, of course, the insert is also correspondingly frustoconical in shape.

[0015] As an option, the cross-sectional surfaces of the insert and the cavity do not have to be circular, but can also be oval, polygonal, rectangular or square, wherein, of course, for rectangular and / or square designs, the side lines of the rectangle or square should not be oriented perpendicular to the rolling direction, especially for rolling bearings.

[0016] As an option, the rolling surface element can be the inner rolling surface element or the outer rolling surface element of a roller bearing, in particular, the rolling surface element can be the inner rolling surface element or the outer rolling surface element of a roller bearing with an inner diameter equal to 250 mm, in particular, the rolling surface element can be the inner rolling surface element or the outer rolling surface element of a roller bearing with an inner diameter greater than or equal to 400 mm.

[0017] As an option, the insert may be formed to be similar in nature at least to the area of ​​the rolling surface element surrounding the insert. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further advantages, features and details of the present invention result from the exemplary embodiments of the present invention described below with reference to the drawings.

[0019] Figure 1 shows the upper region of a longitudinal section of a repaired cylindrical roller bearing outer ring according to a first embodiment, and

[0020] Figure 2 The upper region of a longitudinal section through a repaired cylindrical roller bearing outer ring according to a second embodiment is shown. DETAILED DESCRIPTION

[0021] Figure 1 The upper region of a longitudinal cross-section of a repaired cylindrical roller bearing outer ring 10, according to a first exemplary embodiment of the present invention, is shown. Here, after at least a suspicion of damage exists (e.g., as indicated by a corresponding status detection sensor), the cylindrical roller bearing associated with the unrepaired cylindrical roller bearing outer ring 10 is removed from its operating environment, disassembled, and at least the outer ring 10 is cleaned. This is a large cylindrical roller bearing with an inner diameter of 450 mm. Large rolling element bearings, in particular, represent a significant investment; therefore, the larger the size of the rolling element bearing, and therefore the higher the cost, the more worthwhile the repair is. Here, the outer ring 10 of the cylindrical roller bearing is formed from through-hardened 100Cr6 rolling bearing steel.

[0022] Afterwards, ultrasonic inspection of the rolled-on race 50 of the removed and cleaned cylindrical roller bearing outer ring 10 revealed cracks at a single, limited circumferential location. A cylindrical cavity was then ground into this area using a mobile grinding machine. The depth of the cavity was chosen to encompass the cracked area and was 7 mm. The diameter of the cavity encompassing the entire crack network was selected to the next full centimeter, in this case 12 cm, allowing the use of an insert 20 selected from prefabricated inserts with a diameter of a whole centimeter and a height in 1 mm steps, formed from through-hardened 100Cr6 rolling bearing steel. Here, the cavity and the insert 20 are adapted to each other diametrically in a press-fit manner. Here, the height of the insert 20 is selected such that after insertion, the insert 20 initially protrudes beyond the rolling track 50 surrounding the insert 20 .

[0023] The selected insert 20 is then coated with thermally conductive paste on its end surface, which is intended to contact the base of the cavity, and cooled using liquid nitrogen, while the cylindrical roller bearing outer ring 10 is simultaneously heated using an inductor. This allows the cooled insert 20 to be inserted into the heated cavity with minimal force. Only after the temperatures between the insert 20 and the cylindrical roller bearing outer ring 10 have equalized is the desired press-fit-type fixation of the insert 20 in the cavity established.

[0024] Thereafter, in order to remanufacture the original rolling track 50, the protruding areas of the insert 20 are ground and honed using a movable grinding and honing machine. Figure 1 The repaired cylindrical roller bearing outer ring 10 shown in FIG. It can then be reinstalled with the remaining bearing components of the cylindrical roller bearing and relubricated. Optionally, the repair result can then be subjected to further inspections as described above.

[0025] Figure 2 The upper region of a longitudinal cross section of a repaired cylindrical roller bearing outer ring 10 ′ is shown as a second exemplary embodiment of the present invention. Figure 2 The outer ring of the cylindrical roller bearing 10' and Figure 1 The outer ring of Figure 2In the embodiment, the cavity is constructed as a truncated conical cavity, radially passing through the cylindrical roller bearing outer ring 10', and the insert 20' is also constructed in a corresponding truncated conical manner. Figure 2 The method for repairing the outer ring 10' of the cylindrical roller bearing has no thermal conductive coating on the end side of the insert 20', and optionally, it is also necessary to post-process the end side of the insert 20' that contributes to forming the outer surface of the cylindrical roller bearing outer ring 10'. Figure 1 The above description of Figure 2 Therefore, Figure 2 In the Figure 1 The same reference numerals are indicated with a prime.

[0026] As another option, in Figure 2 In the embodiment, the cavity and the insert can also be configured to rotate, so to speak, by 180° about their horizontal center axis, so that the large diameter end of the truncated cone abuts radially outwards, i.e. against the outer surface of the cylindrical roller bearing outer ring, and the small diameter end abuts radially inwards against the rolling raceway. It is therefore particularly advantageous that the insert cannot fall out of the cavity radially inwards; wherein, after the cylindrical roller bearing outer ring has been completely installed in its installation environment, the insert is finally fixed in the opposite direction.

[0027] Of course, the preceding description can be used in the same way with other roller bearings, ie for example with tapered roller bearings and spherical roller bearings, and of course also with ball bearings.

Claims

1. A rolling surface element of a rolling element bearing assembly, the rolling surface element comprising a rolling raceway on which the rolling element is arranged to roll and a cavity located in the region of the rolling raceway, the opening surface of the cavity being less than 25% of the total rolling raceway surface, for repairing the rolling surface element of the rolling element bearing assembly, wherein: An insert that helps form the rolling track is inserted into the cavity in a press-fit manner.

2. The rolling surface element according to claim 1, characterized in that The cavity is cylindrically configured and the insert is correspondingly disk-shaped and / or the insert is inserted from the side on which the rolling track is provided.

3. The rolling surface element according to claim 1, characterized in that The cavity is configured as a through-portion penetrating the rolling surface element.

4. The rolling surface element according to any one of claims 1 to 3, characterized in that The rolling surface element is an inner rolling surface element or an outer rolling surface element of a roller bearing.

5. The rolling surface element according to any one of claims 1 to 3, characterized in that The insert is formed at least in a similar manner to the area of ​​the rolling surface element around the insert.

6. The rolling surface element according to claim 2, characterized in that The cavity is designed to be cylindrical.

7. The rolling surface element according to claim 2, characterized in that: The insert is accordingly designed in the form of a disk.

8. The rolling surface element according to claim 3, characterized in that The penetration portion and the insert are configured in a frustoconical shape.

9. The rolling surface element according to claim 4, characterized in that The rolling surface element is an inner rolling surface element or an outer rolling surface element of a roller bearing having an inner diameter equal to 250 mm.

10. The rolling surface element according to claim 4, characterized in that The rolling surface element is an inner rolling surface element or an outer rolling surface element of a roller bearing having an inner diameter greater than or equal to 400 mm.

11. A method for repairing a rolling surface element of a rolling element bearing assembly, the rolling surface element comprising a rolling raceway on which a rolling element is arranged to roll, the method comprising the following steps: - identifying at least one region of the rolling path which is no longer flawless, - machining a cavity including the identified area, - inserting an insert adapted to the cavity into the cavity in a press-fit manner, wherein the insert is configured such that it protrudes beyond a rolling surface around the insert, - Erosion of the protruding areas of the insert to remanufacture the rolling track.

12. The method according to claim 11, characterized in that For the inserting step, the insert is cooled and at least the region of the rolling surface element around the cavity is heated.

13. The method according to claim 11 or 12, characterized in that: Prior to the inserting step, the insert is provided with a thermally conductive paste on a side of the insert opposite to the base of the cavity.

14. The method according to claim 11 or 12, characterized in that: The geometry of the cavity is selected so that inserts which are staggered in size, predetermined and prefabricated can be used.

15. The method according to claim 11 or 12, characterized in that: - before the identification step, the rolling element bearing comprising the supply rolling surface element is removed from its mounting environment and disassembled at least sufficiently to enable free access to the supply rolling raceway and to clean at least the supply rolling raceway of contaminants and lubricants adhering thereto, - Identification steps include visual inspection, ultrasound and / or stray current, - machining using a mobile CNC milling machine and / or grinding machine and / or spark erosion machine, - ablation of the protruding areas of the insert by milling, grinding and / or honing using a mobile CNC milling, grinding and / or honing machine, and / or - Reassembling the rolling element bearing including the repaired rolling surface element and reinstalling the rolling element bearing including the repaired rolling surface element in its installation environment, wherein the rolling element bearing or its installation environment that is not yet equipped with a condition detection sensor is provided with such a condition detection sensor in order to verify a flawless repair result in its installation environment or outside at least during a test run.

16. The method according to claim 12, characterized in that The cooling is achieved using liquid nitrogen.

17. The method according to claim 12, characterized in that The heating is achieved using an induction method.

18. The method according to claim 13, characterized in that Before being inserted into the cavity of a few millimeters in depth, the insert is provided with thermally conductive paste on its side opposite to the base of the cavity.

19. The method according to claim 15, characterized in that Verify flawless repair results based on evaluation of captured vibrations and / or temperature.

20. The method according to claim 15, characterized in that Flawless restoration results are verified based on the evaluation of captured oscillations.

21. The method according to claim 15, characterized in that Fresh lubricant is provided to the rolling element bearing including the repaired rolling surface element.

22. The method according to claim 11, characterized in that The no longer flawless areas include damaged areas.

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