Rolling bearing and method for manufacturing same

Abstract

Disclosed is a rolling bearing comprising at least one outer ring (1), at least one inner ring (2) and at least one rolling element (3) arranged between the at least one outer ring (1) and the at least one inner ring (2) wherein an outer surface of the at least one outer ring (1) is configured to fit into a first element and an outer surface of the at least one inner ring (2) is configured to fit into a second element. The inner surface of the inner ring (2) is configured to fit to a second element, and the first element and the second element are rotatable relative to each other, with a polymer composite sheet layer (6) bonded to at least one of the outer surface of the outer ring (1) and the inner surface of the inner ring (2) using a bonding agent.

Description

Technical Field

[0001] The invention relates to a rolling bearing. In addition, the invention relates to a method for producing a rolling bearing. Background Art

[0002] Many rotating mechanical devices may include rolling bearings that enable relative rotation between a first element and a second element. For example, the first element may be a housing and the second element may be a rotating shaft, wherein the outer ring of the rolling bearing is fitted into the housing and / or the inner ring of the rolling bearing is fitted onto the shaft. Depending on the specific application, it may happen that either due to a load that deforms the ring or due to design, one of these fits is a loose fit, which may cause the ring to creep.

[0003] In some cases, this ring creep may cause so-called ring creep wear damage. For example, if a steel outer ring is loosely fitted into an aluminum alloy housing, the ring creep of the outer ring has the opportunity to cause ring creep wear damage on the aluminum alloy housing due to the relative movement between the outer ring and the housing (ring creep movement). In other words, the outer diameter surface of the outer ring and the inner surface of the housing rub against each other, causing wear on the housing. When the wear of the housing increases, backlash may occur in the rotating support part, resulting in abnormal vibration and out of order of the rotating mechanical equipment. This may further lead to a loss of alignment, which may cause undesirable noise. In addition, creep wear may cause debris and / or contaminants, which may damage components of the bearing and / or mechanical equipment, such as gears, which may shorten the life of the bearing and / or mechanical equipment.

[0004] This ring creep movement can be prevented by interlocking or rubber O-rings. However, in practice, interlocking mechanisms and rubber O-rings are not an ideal solution because it is difficult to implement and / or unreliable. Polymer coatings of the friction surfaces ( / rubbing surfaces) consisting of solid lubricants and a manganese-phosphating (i.e. MnPh) pretreatment are another alternative to reduce creep wear. So far, the coatings consist of antimony (Sb), which is considered a material toxic to human health, and the necessary coating process ( / treatment) is very complicated because the entire bearing needs to be immersed in an acid liquid bath for the manganese-phosphating process ( / treatment) and the thermal curing of the polymer coating.

[0005] Therefore, the object of the present invention is to provide a measure for reducing creep wear damage, overcoming the above-mentioned disadvantages. Summary of the invention

[0006] This object is achieved by a rolling bearing according to claim 1 and a method for producing a rolling bearing according to claim 12 .

[0007] Hereinafter, a rolling bearing is provided, which includes at least one outer ring, at least one inner ring, and at least one rolling element arranged between the at least one outer ring and the at least one inner ring. The outer surface of the at least one outer ring is configured to be assembled into a first element (such as a housing), and the inner surface of the inner ring is configured to be assembled into a second element (such as a shaft), wherein the first element and the second element are rotatable relative to each other.

[0008] The outer surface of the at least one outer ring may be the outer surface of the ring in the radial direction of the bearing, such as the outer circumferential surface of the outer ring. The inner surface of the at least one inner ring may be the inner surface of the ring in the radial direction of the bearing, such as the inner hole of the inner ring. For example, the rolling bearing may be a ball bearing, a cylindrical roller bearing, a tapered roller bearing, etc. In addition, the outer ring and / or the inner ring may be made of a first material. The first material may be steel, in particular bearing steel. The first element and / or the second element may be made of a second material different from bearing steel. In particular, the second material may be softer than the first material. For example, the second material may be aluminum, an aluminum alloy, etc. In addition, the roller bearing may be used in an electric motor, such as an electric vehicle, or a pump.

[0009] In order to reduce creep wear and manufacturing costs, a polymer composite sheet layer is bonded to at least one of the outer surface of the outer ring and the inner surface of the inner ring using a bonding agent. Such a polymer composite sheet layer can reduce the wear on the elements assembled to the outer ring and / or the inner ring, so that abnormal vibration and / or noise can be reduced. In addition, the polymer composite sheet layer or liner can be cut to a certain size before bonding the polymer composite sheet layer to the surface, which can reduce manufacturing costs. In particular, the coating process can be omitted. In addition, if the polymer composite sheet layer is worn, the polymer composite sheet can be replaced.

[0010] Preferably, the polymer composite sheet layer comprises polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyester (PET), polyurethane (TPU), polyethylene (PE), polypropylene (PP), polyimide (PI) and / or polyamideimide (PAI). In particular, these compounds ( / mixtures) can exhibit self-lubricity and can have high wear resistance. In addition, these compounds can be commercially available as sheet materials, which only need to be cut to a certain size, thereby omitting the expensive coating process.

[0011] According to a further preferred embodiment, the polymer composite sheet layer comprises 1-50 wt% (i.e., weight percentage, or weight %), preferably 5-20 wt% of at least one solid lubricant. Preferably, the solid lubricant is molybdenum disulfide (MoS2). Due to the solid lubricant, the amount of wear on the outer ring and / or inner ring surface and / or the first and / or second element can be reduced, which can also reduce the amount of debris. This can reduce damage to the bearing and / or parts of the mechanical device (such as gears), which can lead to a longer life of the bearing and / or the mechanical device.

[0012] The thickness of the polymer composite sheet layer can be between 2 and 200 μm, preferably between 5 and 30 μm. When the layer thickness is less than 2 μm, the polymer composite sheet layer may wear at an early stage and the creep wear resistance may not be maintained for a long time. On the other hand, when the film thickness exceeds 200 μm, the strength of the polymer composite sheet layer may be reduced, so that the polymer composite sheet layer may peel off. Therefore, a layer thickness between 2 and 200 μm allows effective reduction of creep wear and reduces the risk of peeling of the polymer composite sheet layer.

[0013] Preferably, the bonding agent is an adhesive epoxy or cyanoacrylate glue. For example, the epoxy glue may be air-hardening, UV-hardening and / or curing-hardening.

[0014] Furthermore, the bonding agent may be applied as a bonding layer with a thickness of less than 25 μm, preferably less than 5 μm. This allows for a strong bonding of the polymer composite sheet layer to the surface.

[0015] Additionally or alternatively, the polymer composite sheet layer may be provided with an adhesive on one side, wherein the adhesive is an acrylic adhesive or a silicone. Thus, the polymer composite sheet layer may be bonded to at least one of the outer surface of the outer ring and the inner surface of the inner ring without applying a bonding agent in an additional bonding layer. This may reduce manufacturing costs.

[0016] Preferably, before applying the polymer composite sheet layer, the surface roughness of the outer surface of the outer ring and / or the inner surface of the inner ring has a surface roughness Ra of 0.5 μm to 10 μm, preferably 1 μm to 3 μm. This allows improving the bonding of the polymer composite sheet layer on the outer surface of the outer ring and / or the inner surface of the inner ring. Preferably, the back side ( / backside) of the polymer composite sheet layer is pretreated using chemical etching and / or plasma etching. This can improve the bonding of the binder to the polymer composite sheet layer.

[0017] Preferably, the friction coefficient when in dry contact with aluminum alloy is between 0.05 and 0.4. In particular, a lower friction coefficient can indicate a lower amount of creep wear.

[0018] According to another preferred embodiment, the polymer composite sheet layer has a dielectric strength greater than 15 kV / mm and a dielectric constant or relative permittivity lower than 4.

[0019] In the case of rolling bearings used in electric motors (for example in electric vehicles), it may happen that current flows through the bearings and / or voltage is applied to the rolling bearings. Due to the leakage of current through the bearings, the lubricant in the bearings and / or the bearings, in particular the metal surfaces of the bearings, such as the raceways for rolling elements, may be damaged. The damage may include an increase in surface roughness and / or noise, and may impair the bearing function. By providing a polymer composite sheet layer for the outer surface of the outer ring and / or the inner surface of the inner ring, the composite coating can have a dielectric strength greater than 15 kV / mm and a dielectric constant less than 4, the current passing intensity can be significantly reduced, for example greater than 90%, and the service life of the bearing is extended. The relatively high dielectric strength and low dielectric constant of the coating can reduce the current intensity and bearing damage.

[0020] According to another aspect of the present invention, a method for manufacturing a rolling bearing as described above is provided. The method comprises the following steps:

[0021] providing ( / arranging) a polymer composite sheet layer comprising at least a polymer,

[0022] applying a bonding agent on at least one of the outer surface of the outer ring and the inner surface of the inner ring and / or the polymer composite sheet layer, and

[0023] The polymer composite sheet layer is bonded to at least one of the outer surface of the outer ring and the inner surface of the inner ring.

[0024] According to another embodiment, the method further comprises, before applying the polymer composite sheet layer, preparing at least one (or one) of the outer surface of the outer ring and the inner surface of the inner ring to have a surface roughness Ra of 0.5 to 10 μm, preferably Ra of 1 to 3 μm. This allows to improve the bonding of the polymer composite sheet layer on the outer surface of the outer ring and / or the inner surface of the inner ring. Preferably, the back side of the polymer composite sheet layer is pretreated using chemical etching and / or plasma etching. This can improve the bonding of the binder to the polymer composite sheet layer.

[0025] Further preferred embodiments are defined in the dependent claims as well as in the description and the drawings.Therefore, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the following, preferred embodiments of the present invention are described in conjunction with the accompanying drawings, wherein the accompanying drawings are only exemplary and are not intended to limit the scope of protection. The scope of protection is limited only by the accompanying claims.

[0027] These figures show:

[0028] Figure 1 : depicts a cross-sectional view of an example of a rolling bearing according to an embodiment of the present invention,

[0029] Figure 2 : Figure obtained in the experiment, depicting the aluminum wear depth of the polymer composite sheet layer and the reference example, and

[0030] Figure 3 : Diagram obtained during the experiment depicting the wear depth of the polymer composite sheet layer.

[0031] Description of Reference Numerals

[0032] 1 Outer ring

[0033] 1a Outer raceway

[0034] 1b Outer surface

[0035] 2Inner ring

[0036] 2a Inner raceway

[0037] 3 Rolling elements

[0038] 5. Binding layer

[0039] 6 polymer composite sheet layers DETAILED DESCRIPTION

[0040] In the following, identical or similar functional elements are denoted by the same reference numerals.

[0041] In the present invention, the type of rolling bearing 10 is not limited. Figure 1 The ball bearing shown is exemplified. The ball bearing includes: an outer ring 1 having an outer ring raceway 1a, an inner ring 2 having an inner ring raceway 2a, and a plurality of balls 3 arranged between the two raceways 1a, 2a. In addition, the outer diameter surface ( / outer diameter surface) 1b of the outer ring 1 of the ball bearing is assembled to a housing ( / seat) (housing) (not shown), and the inner peripheral surface (inner peripheral surface) of the inner ring 2 is assembled to a shaft member (not shown).

[0042] The outer ring 1 and the inner ring 2 are made of metal, such as bearing steel. In addition, the outer diameter surface 1b of the outer ring 1 is provided with a bonding layer 5 including a bonding agent, which bonds the polymer composite sheet layer 6 to the outer diameter surface 1b of the outer ring 1. In many cases, the housing is made of aluminum or an aluminum alloy (e.g., an aluminum die-cast material) to reduce weight. Since the polymer composite sheet layer 6 of the present invention is softer than aluminum or an aluminum alloy (e.g., an aluminum die-cast material), even if the outer diameter surface 1b of the outer ring and the housing can move relative to each other, the housing will not be damaged.

[0043] The polymer composite sheet layer 6 includes a polymer such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyester (PET), polyurethane (TPU), polyethylene (PE), polypropylene (PP), polyimide (PI) and / or polyamideimide (PAI). In addition, the polymer composite sheet layer 6 may also include at least one solid lubricant. However, the above polymers may also include self-lubricating properties, so that an additional solid lubricant may be omitted.

[0044] If a solid lubricant is added to the polymer composite sheet layer 6, the solid lubricant needs to have lubricating properties and needs to be softer than aluminum or an aluminum alloy which is a representative material of the housing. As the solid lubricant, molybdenum disulfide (MoS2) can be used. The content of the solid lubricant in the polymer composite sheet layer 6 may be between 1 and 50 wt% (i.e., weight percentage, also referred to as weight %), preferably between 5 and 20 wt%.

[0045] The polymer composite sheet layer 6 can be formed by an extrusion method. For example, the raw materials for polymer composite (such as the polymer or polymer mixture used) are dissolved and then flow cast ( / flowcasted), for example, using drum casting (drum cast). The obtained cast material is then stretched forward and / or laterally to a predetermined size, and finally rolled (rolled) to obtain a roll of polymer composite sheet material. This material can then be cut into the desired size. Additives (such as solid lubricants) can be added at the beginning of the extrusion method when the raw materials are dissolved and mixed and / or the additives are coated ( / coated) on the sheet by using a coating method (coating method).

[0046] As a bonding agent, an adhesive epoxy or cyanoacrylate glue can be used. The thickness of the bonding layer 5 is less than 25 μm, preferably less than 5 μm, and can be directly applied to the outer diameter surface 1b of the outer ring. As another option, the polymer composite sheet layer 6 is provided with an adhesive on one side, wherein the adhesive is an acrylic adhesive or silicone.

[0047] Before the polymer composite sheet layer 6 is applied to the outer ring 1, the surface roughness of the outer ring 1 is machined to have a surface roughness Ra of 0.5 to 10 μm, preferably 1 to 3 μm. This allows for improved bonding of the bonding layer 5 on the surface. Then, the polymer composite sheet layer 6 is applied to the bonding layer 5. Preferably, the polymer composite sheet layer 6 can be cut to a certain size before it is bonded to the outer ring 1.

[0048] The thickness of the polymer composite sheet layer 6 is between 2 and 200 μm. When the thickness of the polymer composite sheet layer 6 is less than 2 μm, the polymer composite sheet layer 6 wears at an early stage and cannot maintain creep wear resistance for a long time. On the other hand, when the thickness of the polymer composite sheet layer 6 exceeds 200 μm, the strength of the polymer composite sheet layer 6 decreases, so that the polymer composite sheet layer 6 may peel ( / peel off). The thickness of the polymer composite sheet layer 6 is more preferably 5 μm to 30 μm.

[0049] As another alternative, the polymer composite sheet layer 6 may be bonded to the inner surface of the inner ring 2 when creep occurs in the inner ring and the shaft.

[0050] The present invention will be further described with reference to experimental examples. However, it should be noted that the present invention is not limited thereto.

[0051] In this experiment, the desired effect of the binding membrane of the present invention was verified.

[0052] For the test, a pin on disk test was performed, in which a pin was moved on a disk for a predetermined amount of time with a defined load and a defined contact pressure. This allowed the wear depth and the average friction coefficient to be determined. Two groups of tests were performed, in which in the first group a steel pin was moved on an aluminum disk and in the second group an aluminum pin was moved on a steel disk. In both groups, the steel components, i.e. the pins in the first group and the disks in the second group, were provided with a polymer composite sheet layer made of PEEK, which was cut to size. In addition, an uncoated reference sample was prepared. The polymer composite sheet layer was bonded to the workpiece with an epoxy resin or a cyanoacrylate. As a reference sample, a coating containing a binder, molybdenum disulfide (MoS2) as a solid lubricant and antimony according to the prior art as described, for example, in EP3505783A1 was used.

[0053] The diameter of the steel pin is 82 mm and the diameter of the aluminum pin is 64 mm. The defined load for the steel pin is 20 N and the defined load for the aluminum pin is 10 N, where the average contact pressure for the steel pin is 130 MPa and for the aluminum pin is 124 MPa. The wear depth results for the aluminum (Al) and polymer composite sheet layers are Figure 2 and Figure 3 Shown in.

[0054] Example No. polymer 1 PEEK Reference (ref.) <![CDATA[MoS2,Sb2O3]]> - Uncoated - -

[0055] from Figure 2 and Figure 3 As can be seen in FIG. 5 , the wear on the aluminum and polymer composite sheet layer 6 can be significantly reduced and is significantly less than the reference coating.

[0056] In summary, the polymer composite sheet layer 6 described can reduce wear on an element (such as an aluminum housing) assembled to an outer ring and / or an inner ring, so that abnormal vibration and / or noise can be reduced. The polymer composite sheet layer 6 described has a low coefficient of friction, which can allow the amount of debris to be reduced, resulting in a longer life of the bearing and / or mechanical equipment.

[0057] In addition, the polymer composite sheet layer 6 can be cut to size before being bonded to the metal surface of the outer ring and / or the inner ring. The bonding agent can be applied as a bonding layer and / or applied to one side of the polymer composite sheet layer 6.

Claims

1. A rolling bearing (10), comprising at least one outer ring (1), at least one inner ring (2) and at least one rolling element (3) arranged between the at least one outer ring (1) and the at least one inner ring (2), wherein: The outer surface of at least one outer ring (1) is configured to be assembled into a first element, the inner surface of the inner ring (2) is configured to be assembled into a second element, and the first element and the second element are capable of rotating relative to each other, wherein the polymer composite sheet layer (6) is bonded to at least one of the outer surface of the outer ring (1) and the inner surface of the inner ring (2) using a bonding agent.

2. The rolling bearing (10) according to claim 1, characterized in that: The thickness of the polymer composite sheet layer (6) is between 2 μm and 200 μm, preferably between 5 μm and 30 μm.

3. The rolling bearing (10) according to claim 1 or 2, characterized in that: The polymer composite sheet layer (6) includes polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyester (PET), polyurethane (TPU), polyethylene (PE), polypropylene (PP), polyimide (PI) and / or polyamideimide (PAI).

4. The rolling bearing (10) according to any one of the preceding claims, characterized in that The polymer composite sheet layer (6) comprises 1-50 wt%, preferably 5-20 wt% of at least one solid lubricant.

5. The rolling bearing (10) according to claim 4, characterized in that The solid lubricant is molybdenum disulfide (MoS2).

6. Rolling bearing (10) according to any one of the preceding claims, characterized in that The bonding agent is a viscous epoxy or cyanoacrylate glue.

7. Rolling bearing (10) according to any one of the preceding claims, characterized in that The bonding agent is applied as a bonding layer (5) with a thickness of less than 25 μm, preferably less than 5 μm.

8. Rolling bearing (10) according to any one of the preceding claims, characterized in that The polymer composite sheet layer (6) is provided with an adhesive on one side, wherein the adhesive is an acrylic adhesive or silicone.

9. Rolling bearing (10) according to any one of the preceding claims, characterized in that Before applying the binder on the polymer composite sheet layer, the back side of the polymer composite sheet layer is pre-treated using chemical etching and / or plasma etching.

10. Rolling bearing (10) according to any one of the preceding claims, characterized in that The friction coefficient for dry contact with aluminum alloy is between 0.05 and 0.

4.

11. Rolling bearing according to any one of the preceding claims, characterized in that The polymer composite sheet layer (6) has a dielectric strength greater than 15 kV / mm and a dielectric constant lower than 4.

12. A method for producing a rolling bearing (10) according to any one of the preceding claims, wherein: The rolling bearing (10) comprises at least one outer ring (1), at least one inner ring (2) and at least one rolling element (3) arranged between the at least one outer ring (1) and the at least one inner ring (2), wherein the outer surface of the at least one outer ring (1) is configured to be fitted into a first element, the inner surface of the inner ring (2) is configured to be fitted into a second element, and the first element and the second element are rotatable relative to each other, wherein the method comprises the following steps: providing a polymer composite sheet layer (6) comprising at least a polymer, and applying a bonding agent to at least one of the outer surface of the outer ring (1) and the inner surface of the inner ring (2) and / or the polymer composite sheet layer (6), and The polymer composite sheet layer (6) is bonded to at least one of the outer surface of the outer ring (1) and the inner surface of the inner ring (2).

13. The method for manufacturing a rolling bearing according to claim 12, characterized in that The method further comprises, before applying the polymer composite sheet layer (6), pre-treating the back side of the polymer composite sheet layer using chemical etching and / or plasma etching.

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