Insulated bearing and manufacturing method thereof

Abstract

The invention provides an insulating bearing which comprises an outer ring, an inner ring and a rolling body arranged between the outer ring and the inner ring, at least one of the outer ring and the inner ring is arranged as an insulating ferrule, the insulating ferrule comprises a body and an insulating layer overmolded on the surface of the body, the dielectric constant of the insulating layer is lower than 5at1 MHz, more preferably lower than 4at1 MHz, and the dielectric constant of the insulating layer is more preferably lower than 4at1 MHz. And more preferably, the frequency is lower than 3.5 at1 MHz. The invention further provides a manufacturing method of the insulating bearing. The manufacturing method comprises the step that a sprue of an injection molding machine for overmolding the insulating layer is arranged to enable a weld line of the overmolded insulating layer to avoid a main stress bearing area of the insulating ferrule and / or to be formed at the position, with the maximum thickness, of the insulating layer. The insulating layer is coated and molded on the surface of the insulating ferrule body, so that the insulating layer can provide enough insulativity even under the conditions of high voltage and high-frequency current, and the bearing is further prevented from being electrically corroded.

Description

Technical Field

[0001] The present invention relates to an insulated bearing and a manufacturing method thereof. Background Art

[0002] Bearings are widely used in various types of equipment. Different application fields often put forward various different requirements for bearings.

[0003] Taking an electrical equipment such as an electric vehicle as an example, since its drive motor shaft, transmission drive shaft, etc. need to use bearings, such bearings work in a charged environment. Moreover, since the charging of electric vehicles increasingly pursues increasing the charging voltage to shorten the charging time, the bearings on the motor shaft are also exposed to an increasingly high voltage environment. When there is current flowing through the bearing, it will cause electrical corrosion to the bearing.

[0004] Therefore, the prior art proposes to electrically insulate the bearing to prevent current from flowing through the bearing. Common insulation solutions include electrically insulating at least one of the outer ring, rolling elements, and inner ring of the bearing. For example, one solution is to apply an insulating coating to the outer ring, inner ring, or rolling elements, or even directly manufacture the rolling elements with an insulating material (such as ceramics).

[0005] There is also a solution to mold an insulating layer outside the outer ring / inner ring of the bearing, and this insulating layer is coated and molded onto the outer peripheral surface and axial end surface opposite to the raceway. However, since the bearing often moves at high speed and under high load, although the insulating layer is coated and molded on the outer ring / inner ring, after long-term operation, the insulating layer inevitably undergoes axial and / or circumferential movement, thereby causing damage to the insulating layer and affecting the insulation of the entire bearing.

[0006] In addition, in the prior art, whether using a ceramic coating or a coated and molded insulating layer, their insulation protection performance is not satisfactory when there is high voltage or high-frequency current.

[0007] Therefore, there is a need in the art for a technical solution that can effectively provide insulation and thus effectively prevent the movement of the insulating layer. Summary of the Invention

[0008] In view of the problems and needs mentioned above, the present disclosure proposes a novel technical solution, which solves the above problems and brings other technical effects due to the following technical features.

[0009] The present invention provides an insulated bearing, including an outer ring, an inner ring, and rolling elements disposed between the outer ring and the inner ring, wherein at least one of the outer ring and the inner ring is provided as an insulating ring, and the insulating ring includes a body and an insulating layer coated and molded on the surface of the body, and the dielectric constant of the insulating layer is less than 5 @1MHz, more preferably less than 4 @1MHz, and even more preferably less than 3.5 @1MHz.

[0010] The present invention also provides a method for manufacturing an insulating bearing as described above, including: setting the gate of an injection molding machine for overmolding the insulating layer so that the weld line of the overmolded insulating layer avoids the main stress-bearing area of the insulating ring and / or is formed at the position where the thickness of the insulating layer is the largest.

[0011] The present invention improves the insulation performance of bearings working in an electrical environment. In particular, for the case of high voltage and high-frequency current encountered by bearings, an insulating layer with a dielectric constant lower than 3.5 @ 1 MHz is overmolded on the ring (inner ring and / or outer ring). Preferably, the insulating layer is made of a polymer alloy, and preferably, the mechanical properties and thermal conductivity are further optimized by adding glass fiber / thermal conductive material. Therefore, the present invention provides an insulating bearing with good insulation and suitable for a harsh working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a cross-sectional view of an insulating ring according to a first preferred embodiment of the present invention;

[0013] Figure 2 is a partial perspective view of an insulating ring according to a first preferred embodiment of the present invention and an enlarged view of the knurling structure;

[0014] Figure 3 is a cross-sectional view of an insulating ring according to a second preferred embodiment of the present invention;

[0015] Figure 4 is an enlarged view of the knurling structure in an insulating ring according to a second preferred embodiment of the present invention;

[0016] Figure 5 is a cross-sectional view of an insulating ring according to a third preferred embodiment of the present invention;

[0017] Figure 6 is an enlarged view of the knurling structure in an insulating ring according to a third preferred embodiment of the present invention;

[0018] Figure 7 is a cross-sectional view of an insulating ring according to a fourth preferred embodiment of the present invention;

[0019] Figure 8A and Figure 8B is a cross-sectional view of an insulating ring according to a fifth preferred embodiment of the present invention;

[0020] Figure 9 is a cross-sectional view of an insulating ring according to a modification of the present invention;

[0021] Figure 10 is a schematic diagram for explaining the formation of the weld line of the insulating layer;

[0022] Figure 11 Schematic diagram of each gate position in the method for manufacturing an insulating bearing according to a preferred embodiment of the present invention. Detailed implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the technical solutions of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of specific embodiments of the present disclosure. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure.

[0024] Compared with the embodiments shown in the accompanying drawings, the feasible implementation solutions within the scope of protection of the present disclosure may have fewer components, have other components not shown in the accompanying drawings, different components, components arranged differently or components connected differently, etc. In addition, two or more components in the accompanying drawings may be implemented in a single component, or a single component shown in the accompanying drawings may be implemented as multiple separate components.

[0025] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art belonging to the field of the present disclosure. The "first", "second" and similar terms used in the specification and claims of the patent application of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. When the number of components is not specified, the number of components may be one or more; similarly, the similar terms such as "a", "the", "said" do not necessarily indicate a quantity limitation. The terms such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "mounted", "arranged", "connected" or "coupled" are not limited to physical or mechanical mounting, arrangement or connection, but may include electrical mounting, arrangement or connection, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent the relative orientation relationship during the use of the device or the orientation relationship shown in the accompanying drawings. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0026] For ease of description, in this article, the direction of the rotation axis of the bearing is referred to as the axial direction, and the direction perpendicular to the axial direction is referred to as the radial direction. The terms "inner / towards the inside" mean along the direction towards the inside of the bearing. Conversely, the terms "outer / towards the outside" mean towards the outside of the bearing. In addition, in different embodiments, the same reference numerals are used to refer to components having the same or similar structures and functions.

[0027] The insulating bearing according to the present invention will be described below with reference to the preferred embodiments shown in the accompanying drawings. The insulating bearing according to the present invention includes an outer ring, an inner ring (not shown), rolling elements (not shown) provided between the outer ring and the inner ring, etc. Generally, the outer ring and the inner ring are also collectively referred to as rings. As described above, in order to achieve the insulating performance of the bearing, at least one of the outer ring and the inner ring can be set as an insulating ring. Therefore, the insulating ring of the insulating bearing according to the present invention includes a body and an insulating layer coated and molded on the surface of the body. In addition, the body further includes: a raceway; an axial end face; a radial outer peripheral surface, which is arranged to face away from the raceway in the radial direction; wherein, a groove is included on the surface of the body, and the insulating layer is coated and molded on the body 1 and embedded in the groove, so that the groove can effectively hold the insulating layer to prevent the insulating layer from moving axially / circumferentially. It should be understood that the surface can be any suitable one or more surfaces on the insulating ring body (of course, this surface does not include the raceway surface), and the groove can be grooves of any form and quantity formed on this surface.

[0028] The insulating bearing according to the present invention will be further introduced below with reference to the preferred embodiments of the present invention.

[0029] Figure 1 and Figure 2 The first preferred embodiment according to the present invention is shown. This embodiment and other embodiments hereinafter will take the outer ring of the bearing as an example to introduce the characteristics of the insulating bearing and its insulating ring according to the present invention.

[0030] Specifically, in the first preferred embodiment, an insulating layer 6 is coated and molded on the surface of the body 1 of the insulating ring, wherein the dielectric constant of the insulating layer 6 is less than 5 @1 MHz, more preferably less than 4 @1 MHz, and more preferably less than 3.5 @1 MHz. It should be understood that the surface of the body 1 mentioned here can be any suitable surface, for example, including the axial end face 3; the radial outer peripheral surface 4, which is arranged to face away from the raceway 2 in the radial direction; the axial flange 5, which protrudes axially outward relative to the axial end face 3; and the radial inner peripheral surface 50 of the axial flange 5 facing the inner side of the bearing (see Figure 2 ). Therefore, the insulating layer 6 can be coated and molded on a part or all of these surfaces of the body 1 as needed.

[0031] By coating and molding such an insulating layer on the surface of the insulating ring body, even in the case of high voltage and high-frequency current, the insulating layer can provide sufficient insulation, thereby preventing the bearing from being electro-corroded.

[0032] In addition, it should be noted that although there are various known materials capable of achieving insulation performance and various measures capable of achieving insulation effects, not any insulating material or insulating means can meet the insulation performance requirements of bearings operating in an electrical environment, especially under high-frequency and high-voltage conditions. For example, although some materials themselves have good insulation performance, such materials cannot form insulating materials for bearings alone.

[0033] According to further research by the present inventor, the present inventor adopted a method of covering an insulating layer on the bearing ring and optimizing its dielectric constant by optimizing the material ratio of the insulating layer to achieve the object of the present invention.

[0034] Specifically, for blocking high-frequency current, if it is necessary to make it have a smaller capacitance, the dielectric constant can be reduced, and then the capacitance can be reduced.

[0035] If the inner and outer rings of the bearing can be regarded as a parallel plate capacitor, then according to the formula C = εS / d (where C is the capacitance value of the parallel plate capacitor, ε is the dielectric constant of the medium between the plates, S is the area of the plates, and d is the distance between the plates), a material with a lower dielectric constant will result in a smaller capacitance value of the bearing, and thus better impedance. Moreover, according to the research of the present inventor, when the dielectric constant of the insulating layer is lower than 5 @1MHz, more preferably lower than 4 @1MHz (more preferably lower than 3.5 @1MHz), the above object of the present invention can be better achieved.

[0036] According to a preferred embodiment of the present invention (as described later), the present invention provides an insulating layer formed, for example, by a polymer alloy, which includes a continuous phase as a matrix. Subsequently, two methods are adopted to further optimize its dielectric constant. First, a low-dielectric material is introduced as a dispersed phase (such as polyphenylene oxide (PPO) described later, whose dielectric constant is 2.7@1GHz); second, glass fiber is introduced (such as D glass fiber, ; or quartz glass fiber, whose dielectric constant is 3.7~3.8 @1MHz; or the commonly used E glass fiber (alkali-free glass fiber) with a dielectric constant of 6.5@ 1MHz).

[0037] In addition, in a more simplified embodiment, the insulating layer 6 can be formed, for example, by a polymer. The polymer is, for example, polyphenylene sulfide or aromatic nylon. Further, the electrical and insulation properties of the insulating layer can also be adjusted by adding glass fiber, etc.

[0038] The preferred embodiments of the present invention will be further described below based on the above concepts and principles.

[0039] As described above, according to a preferred embodiment of the present invention, the insulating layer 6 can be formed, for example, by a polymer alloy, and the polymer alloy includes a continuous phase and a dispersed phase.

[0040] Further preferably, when the insulating layer 6 is formed of a polymer alloy, for example, the continuous phase may be polyphenylene sulfide (PPS), or aromatic polyamide (PPA, such as (PA9T, PA10T)), or a mixture of PPS and PPA. The continuous phase not only provides good insulation performance, but also is suitable for providing sufficient load-bearing capacity, heat resistance, and corrosion resistance for bearings working in harsh and complex environments.

[0041] Further preferably, in the polymer alloy, the content of the continuous phase may be 20-70 wt% (weight percentage), more preferably 40-60 wt%.

[0042] Further preferably, when the continuous phase includes PPS, that is, when the polymer alloy is formed of PPS alone or formed by mixing PPS and PPA, the PPS may be linear PPS and / or crosslinked PPS.

[0043] However, for some more stringent insulation requirements, continuous phases such as PPS and PPA still face the problem of relatively high dielectric constants. Therefore, more preferably, the dispersed phase may be selected as polyphenylene oxide (PPO); preferably, in the polymer alloy, the content of the dispersed phase is 5-25 wt%, more preferably 10-20 wt%. Because PPO generally has a lower dielectric constant, by adding PPO, the dielectric constant of the polymer alloy can be further adjusted, for example, the dielectric constant of the entire polymer alloy can be further reduced. And PPO has a high glass transition temperature, which can improve the dimensional stability of the material.

[0044] According to another preferred embodiment of the present invention, the insulating layer 6 may further include glass fibers to adjust the mechanical properties of the entire insulating layer, such as increasing its mechanical strength, etc.

[0045] In addition, generally, glass fibers have a relatively high dielectric constant. Therefore, for the purpose of adapting to the present invention, as described above, the glass fibers are preferably E-glass fibers, D-glass fibers, and / or quartz glass fibers with a lower dielectric constant.

[0046] Further preferably, in the polymer alloy, the content of the glass fibers is 20-60 wt%, more preferably 40-60 wt%.

[0047] Based on a large number of research experiments conducted by the present inventors on various insulation layer materials, and the experiments show that for the bearing insulation application proposed in the present invention, when the dielectric constant of the insulation layer is lower than 5 @1MH, especially lower than 4 @1MHz, an insulated bearing that meets the electrical requirements can be obtained. At the same time, the insulation layer also has excellent mechanical properties to meet the operating requirements of the bearing. The comparison of some experiments is shown in the following table. Generally speaking, by adjusting the material composition of the insulation layer so that its dielectric constant is 4 @1MHz or lower while still taking into account its mechanical properties, an insulated bearing that is more suitable for high-frequency and high-voltage applications can be obtained.

[0048]

[0049] According to another preferred embodiment of the present invention, the insulation layer 6 may further include a thermal conductive material to adjust the thermal conductivity of the entire insulation layer. Especially for bearings, due to their working environment and their own rotation, a large amount of heat may be generated on the bearings. Therefore, improving the thermal conductivity of the insulation layer can better transfer the heat in the bearings.

[0050] Preferably, the thermal conductive material may be one or more of hexagonal boron nitride (h-BN), Al2O3, AlN, BeO, Si3N4, MgO, SiO2.

[0051] To take into account the performance requirements in all aspects above, according to a preferred embodiment, the polymer alloy used to form the insulation layer may include 20 - 70wt% of the continuous phase, 5 - 25wt% of the dispersed phase, 20 - 60wt% of glass fiber, and the rest is the thermal conductive material.

[0052] In addition, for the bearings commonly used in electric vehicle drive assemblies, in order to avoid electrocorrosion, the thickness of the insulation layer 6 needs to be set between 0.2mm and 2mm, preferably between 0.4mm and 1.2mm.

[0053] The present invention has improved the insulation performance of bearings working in an electrical environment. Especially for the situation of high voltage and high-frequency current encountered by bearings, it is proposed to coat and mold an insulation layer with a dielectric constant lower than 5 @1MHz on the raceway (inner ring and / or outer ring). And preferably, the insulation layer is made of a polymer alloy, and preferably, the mechanical properties and thermal conductivity are further optimized by adding glass fiber / thermal conductive material. Therefore, the present invention provides an insulated bearing with good insulation and suitable for a harsh working environment.

[0054] It should also be understood that although the insulation layer is introduced for the Figure 1-2 first preferred embodiment shown, this insulation layer can also be applied to all other preferred embodiments described later, so it will not be repeatedly described for each embodiment.

[0055] Continue to refer to Figure 1 and 2 In the preferred embodiment, the radially inner peripheral surface 50 includes an inner radial groove 51 (which is recessed substantially in the radial direction); wherein, the insulating layer 6 is overmolded on the radially outer peripheral surface 4 and the axial flange 5, and the insulating layer 6 is embedded in the inner radial groove 51.

[0056] Figure 1 The left figure of shows the state without overmolding the insulating layer 6, Figure 1 The right figure of shows the state after overmolding the insulating layer 6.

[0057] It should be understood that the inner radial groove 51 can be formed by any suitable means, such as by machining such as turning. The insulating layer 6 can also be formed by any suitable overmolding means. According to the present invention, by providing such an inner radial groove 51, the molded insulating layer 6 is embedded in the inner radial groove, so that the movement of the insulating layer 6 in the axial direction X can be effectively prevented.

[0058] Further refer to Figure 2 , which shows a partial perspective view of the insulating ferrule and an enlarged view of part A. Further preferably, the inner radial groove 51 further includes a knurling structure 80. The knurling structure 80 is processed by a knurling tool to form an uneven structure on the surface of the inner radial groove 51, that is, dozens or even hundreds of smaller grooves 81 are further processed in the inner radial groove 51. The knurling structure 80 can be, for example, straight knurling. In addition, as Figure 2 shown, the knurling structure 80 is formed on the side surface of the inner radial groove 51 that is farther from the raceway 2. However, according to actual needs, in a preferred embodiment not shown, such a knurling structure can also be formed on the other side surface and / or the bottom surface of the inner radial groove 51 that is closer to the raceway 2.

[0059] By processing such a knurling structure 80 in the inner radial groove 51, the insulating layer 6 will be further embedded in the grooves 81 of the knurling structure 80, thereby strengthening the connection strength between the insulating layer 6 and the inner radial groove 51. And since the knurling structure 80 is distributed in the circumferential direction of the ferrule body 1, the circumferential movement of the insulating layer 6 can be further prevented.

[0060] Figure 3 shows the second preferred embodiment of the present invention. In this preferred embodiment, the axial flange 5 of the body 1 of the insulating ferrule may include an axial groove 53 (which is recessed substantially in the axial direction) on its axially outer end surface 52, and the insulating layer 6 is further embedded in the axial groove 53, as Figure 3 shown in the right figure of

[0061] Further preferably, asFigure 4 As shown, the axial groove 53 may also include a knurling structure 80, and the insulating layer 6 is further embedded into the groove 81 of the knurling structure 80 to further strengthen the connection between the insulating layer 60 and the axial groove 53, thereby preventing the circumferential movement of the insulating layer 6. The knurling structure 80 is formed, for example, in the bottom surface of the axial groove 53. According to an embodiment not shown, the knurling structure may also be formed in the side surface of the axial groove 53.

[0062] Figure 5 The third preferred embodiment of the present invention is shown, which is a further improvement of the first and / or second preferred embodiments. In this third preferred embodiment, the body 1 of the insulating ferrule further includes corner grooves 7 provided at the intersection between the radially outer peripheral surface 4 and the axial flange 5. The corner grooves 7 are preferably provided in two numbers, and the insulating layer 6 is further embedded into the corner grooves 7, as Figure 5 shown in the right figure of. By providing such corner grooves 7, the axial movement of the insulating layer 6 can also be effectively prevented.

[0063] Further preferably, referring to Figure 6 , the corner groove 7 may also include a knurling structure 80, and the insulating layer 6 is further embedded into the groove 81 of the knurling structure 80 to further strengthen the connection between the insulating layer 60 and the axial groove 53. As Figure 6 shown, the knurling structure 80 is provided on the bottom surface of the corner groove 7. According to an embodiment not shown, the knurling structure 80 may also be provided on the side surface of the corner groove 7.

[0064] Figure 7 The fourth preferred embodiment of the present invention is shown. Although Figure 7 shown with reference to the cross-sectional view of the third embodiment of Figure 5 , it should be understood that it may be a variant of any of the foregoing preferred embodiments, or may also be implemented independently.

[0065] Specifically, in this fourth preferred embodiment, the radially outer peripheral surface 4 of the body 1 of the insulating ferrule may include outer radial grooves 41 (shown in dotted lines, recessed substantially in the radial direction). The outer radial grooves 41 are preferably provided in two numbers, and the insulating layer 6 is further embedded into the outer radial grooves 41.

[0066] Further preferably, the outer radial groove 41 may also include a knurling structure (not shown), for example, provided on the bottom surface and / or side surface of the outer radial groove 41, and the insulating layer 6 is further embedded into the groove of the knurling structure.

[0067] It should be understood that when such an outer radial groove 41 is formed only on the radial outer peripheral surface 4, it exists independently of the other grooves described above, and can also prevent the axial / circumferential movement of the insulating ring, so the axial flange 5 and its related grooves in the foregoing preferred embodiment can also be omitted. Therefore, the position of the outer radial groove 41 can be set flexibly. For example, it can also be like the corner groove 7 in the Figure 5 third preferred embodiment, and is provided at the intersection between the radial outer peripheral surface 4 and the axial end face 3.

[0068] In addition, since the insulating ring often has to bear a certain radial force and this radial force mainly acts on the main stress-bearing area in the middle of the insulating ring (as shown by the dashed ellipse in Figure 7 ), if the outer radial groove 41 is provided in the middle of the insulating ring, it will cause a large stress concentration. Therefore, further preferably, the outer radial groove 41 is provided to be offset in the axial direction relative to the raceway symmetry plane P (the raceway symmetry plane P is perpendicular to the axial direction X and the raceway 2 is approximately symmetric about the raceway symmetry plane P), so that the outer radial groove 41 is away from the main stress-bearing area of the insulating ring, thereby avoiding adverse effects of the outer radial groove 41 on the stress condition of the bearing.

[0069] In addition, since Figure 6 in the embodiment, the groove is provided at the corner, so there is no groove on its radial outer peripheral surface 4. Therefore, its stress condition is relatively better than that of the Figure 7 embodiment, and it is more suitable for bearings that need to bear a large radial force.

[0070] According to a further preferred modification of the present invention, any one of the inner radial groove 51, the axial groove 53, the corner groove 7, and the outer radial groove 41 described above can be provided as a continuous groove or discontinuous multiple grooves in the circumferential direction. When forming discontinuous multiple grooves (not shown), the multiple grooves can be spaced evenly or unevenly in the circumferential direction and their number can also be set and adjusted according to actual needs, so the circumferential movement of the insulating layer can also be effectively prevented.

[0071] According to a further preferred modification of the present invention, in addition to providing a knurled structure in the various grooves as described above, a knurled structure (not shown) can also be provided on at least one of the radial outer peripheral surface 4 and the axial outer end face 52 of the axial flange 5, such as a diamond knurl, and the insulating layer 6 is further embedded in the grooves of the knurled structure.

[0072] On the other hand, in each of the foregoing preferred embodiments, the molded insulating layer 6 is formed as the outermost layer of the insulating ferrule. Considering the application environment of the bearing, especially when the outer ring is manufactured as an insulating ferrule, since the outer ring usually also contacts other components (such as the housing), and sometimes there may also be a mating and / or moving relationship with other components, the insulating layer 6 formed by injection molding is not conducive to forming an accurate fit with other components due to its poor dimensional accuracy. Moreover, during the transportation of the bearing, the insulating layer 6 is also prone to being bumped and worn, which may seriously reduce the insulating performance when severe.

[0073] Therefore, according to the fifth preferred embodiment of the present invention as shown in Figure 8A and 8B the present invention further proposes to provide an outer metal ring 9 on the outer side of the insulating layer 6. The outer metal ring 9 at least covers the radial outer surface of the insulating layer 6. Preferably, the axial width of the outer metal ring 9 may be slightly larger than the axial width of the insulating layer 6.

[0074] During the manufacturing process of such an insulating ferrule, for example, the outer metal ring 9 and the body 1 of the ferrule can be first placed in an injection mold, and then the material of the liquid insulating layer 6 is injected into the mold from an appropriate position. After the insulating layer 6 is molded, the outer metal ring 9 can be connected and cover the radial outer surface of the insulating layer 6, thereby forming an insulating ferrule with the outer metal ring 9. Of course, the outer metal ring 9 can also be connected and cover the radial outer surface of the insulating layer 6 by any other suitable means.

[0075] Since the outer metal ring 9 is a relatively rigid component, it is easier to control the dimensional accuracy, making it easier for the entire ferrule and even the entire bearing to meet the mating requirements with other components. Moreover, the outer metal ring 9 also provides good wear resistance and impact resistance.

[0076] Preferably, the inner surface (such as the radial inner circumferential surface) of the outer metal ring 9 may also include a knurled structure 90, and the insulating layer 6 is further embedded into the grooves (not marked) of the knurled structure 90 of the outer metal ring 9. Figure 8B Further shows the outer metal ring 9 removed after the insulating layer 6 has been molded to show the morphology of the part of the insulating layer 6 embedded in the knurled structure 90. This embedded connection between the knurled structure 90 and the insulating layer 6 can effectively prevent the radial relative movement between the outer metal ring 9 and the insulating layer 6.

[0077] Preferably, the outer metal ring 9 includes a flange 91 extending radially from its outer periphery, and the flange is embedded into the corner groove 61 of the insulating layer 6. By this setting, the axial relative movement between the outer metal ring 9 and the insulating layer 6 can be further prevented.

[0078] Although Figure 8A and Figure 8B are shown as being inFigure 5 On the basis of the third preferred embodiment shown, the outer metal ring 9 is added. However, it should be understood that according to other preferred embodiments not shown, the outer metal ring 9 can be applied to Figure 1 、 3 and other preferred embodiments shown in FIGS. 7, which will not be elaborated and shown herein.

[0079] According to the above preferred embodiments of the present invention, by providing a "groove" on the body of the ferrule, the axial movement and / or circumferential movement of the insulating layer is restricted, and the specific form and number of the grooves are not limited by any means. In other words, those skilled in the art can understand that the principle of the present invention is to remove some materials on the body of the ferrule and make the molded insulating layer enter the material removal part, thereby increasing the resistance to the axial movement and / or circumferential movement of the insulating layer.

[0080] Therefore, according to another variant of the present invention, as Figure 9 shown, a chamfered portion 54 is provided at the intersection between the outer peripheral surface 4 in the radial direction and the axial flange 5, and the insulating layer 6 can be molded in the chamfered portion 54. Thus, since the chamfered portion 54 is inclined with respect to the axial direction and the radial direction, it can also provide resistance to the axial movement of the insulating layer 6. This resistance effect is the same as that of the "groove" (such as the corner groove 7) in the foregoing preferred embodiments (although the specific form of the chamfered portion 54 is different from that of the foregoing groove, both belong to the material removal part). Preferably, the knurling structure 80 as described above is further provided on the surface of the chamfered portion 54 to further provide restriction to the circumferential movement of the insulating layer 6.

[0081] In addition, Figure 9 the variant shown can also be combined with any of the foregoing preferred embodiments as required. For example, the chamfered portion 54 can be provided in the Figure 1-2 preferred embodiment shown, that is, the ferrule can include both the groove 51 and the chamfered portion 54 to provide a better effect of preventing the axial and circumferential movement of the insulating layer 6. Further preferably, the chamfered portion 54 can be provided as a continuous chamfered portion in the circumferential direction or a plurality of discontinuous chamfered portions.

[0082] Furthermore, Figure 8A and 8B the outer metal ring 9 shown can be applied to the insulating layer 6 in the variant shown in Figure 9 as well, which will not be elaborated herein.

[0083] Finally, it should be understood that, depending on the bearing structure, there is also a case where the axial end face 3 coincides with the axial outer end face 52 of the axial flange 5, or in other words, the ferrule may not include the axial flange 5 protruding axially outward, and both sides of the body 1 only include the axial end face 3. In this case, the groove 51 in the first preferred embodiment may not exist, so that even if only Figure 3 , Figure 5 , Figure 7 , Figure 9 The material removal portion (e.g., grooves 53, 7, 41 or chamfered portion 54) in the embodiment can also prevent the axial / circumferential movement of the insulating layer 6. For example, in an embodiment not shown in which the axial flange 5 does not exist, a groove such as groove 53 can be provided on the axial end surface 3; a corner groove such as corner groove 7 can be provided at the intersection between the axial end surface 3 and the radial outer peripheral surface 4; and a chamfered portion such as chamfered portion 54 can be provided at the intersection between the axial end surface 3 and the radial outer peripheral surface 4.

[0084] In summary, the present invention proposes to provide a material removal portion (such as various grooves or chamfered portions) on the surface of the insulating ferrule body (i.e., any suitable surface), as long as it can provide an obstruction to the axial movement / circumferential movement of the insulating layer. Further, according to the principles of the present invention, the knurling structure can also be understood as a form of the material removal portion.

[0085] As mentioned above, in the insulated bearing of the present invention, the insulating layer is applied to the insulating ring by overmolding, which is usually done by an injection molding machine. Figure 10 Generally speaking, if the gate used for the injection molding machine is set to inject the insulating layer material from position A in the axial direction, the liquid insulating layer material will flow in the mold along all possible flow directions of the ferrule 1. From the circumferential direction, the liquid insulating layer material will converge at the dotted line position on the opposite side of the gate position A (i.e., the position symmetrical about 180° relative to position A) and form a weld line, that is, the weld line will be formed in the main load-bearing area of the ferrule. However, in general, the strength of the weld line is poor, so when the weld line is formed in this main load-bearing area, it will have an adverse effect on the force and operation of the bearing, and may cause premature damage to the insulating layer itself.

[0086] Therefore, according to another aspect of the present invention, the present invention also provides a method for manufacturing an insulating bearing. The method mainly optimizes the gate position of the injection molding machine used for overmolding the insulating layer, so that the weld line of the insulating layer 6 after overmolding avoids the main force bearing area of the insulating ring and / or is formed at the position where the thickness of the insulating layer 6 is the largest.

[0087] For example, see Figure 11 (Refer to the cross-sectional view of the third preferred embodiment) andFigure 1 , 3 5, 7, 9. According to the method of the present invention, the gate of the injection molding machine can be set at multiple positions: for example, the gate can be set to be approximately opposite to the inner peripheral surface 50 of the axial flange 5, as shown by arrow A. This setting is more suitable for Figure 1 the first preferred embodiment; the gate can be set to be opposite to the axial outer end surface 52 of the axial flange 5, as shown by arrow B. This setting is more suitable for Figure 3 the second preferred embodiment and Figure 8A , Figure 8B the fifth preferred embodiment; the gate can be set to be opposite to the intersection between the radial outer peripheral surface 4 and the axial flange 5, as shown by arrow C. This setting is more suitable for Figure 5 the third preferred embodiment and Figure 7 the fourth preferred embodiment and Figure 9 the modification of

[0088] Of course, it should be understood that although the preferred gate positions are proposed for different preferred embodiments above, this is not a limitation. According to actual needs, the above-mentioned gate positions can also be used for other preferred embodiments; even according to actual needs, for a certain preferred embodiment, multiple gates can be set at multiple positions selected from the above positions.

[0089] Finally, although not shown, those skilled in the art can understand that the inner ring and the outer ring of the bearing are arranged on both sides of the rolling elements, and the inner ring has a structure substantially symmetrical to the outer ring. For example, the inner ring also includes raceways, axial end faces, radial outer peripheral surfaces (which are opposite to the inner ring raceways and usually face the rotating shaft), etc. Therefore, the inner ring can similarly include various grooves in the above-mentioned preferred embodiments for holding the insulating layer, and / or an outer metal ring that connects and covers the insulating layer of the inner ring (which can contact the rotating shaft), which will not be elaborated here. That is to say, the "insulating ring" of the present invention can be the outer ring of the bearing or the inner ring of the bearing, as long as the principle of the present invention is implemented.

[0090] In summary, the present invention proposes an insulating bearing and its manufacturing method for the problem of electrical corrosion of bearings used in high-pressure environments. The present invention not only realizes good electrical insulation of the bearing, but also can further prevent the movement of the insulating layer along the axial direction and / or the circumferential direction, greatly improving the electrical performance and service life of the insulating layer and the entire bearing.

[0091] In the above, the exemplary embodiments of the present disclosure have been described in detail with reference to the preferred embodiments. However, those skilled in the art can understand that without departing from the concept of the present disclosure, various modifications and variations can be made to the above specific embodiments, and various combinations of the technical features and structures proposed by the present disclosure can be made without exceeding the protection scope of the present disclosure. The protection scope of the present disclosure is determined by the appended claims.

Claims

1. An insulating bearing, comprising an outer ring, an inner ring, and rolling elements disposed between the outer ring and the inner ring, wherein, At least one of the outer ring and the inner ring is provided as an insulating ring, and the insulating ring includes a body (1) and an insulating layer (6) coated and molded on the surface of the body (1), wherein the dielectric constant of the insulating layer (6) is less than 5 @ 1 MHz, more preferably less than 4 @ 1 MHz, and more preferably less than 3.5 @ 1 MHz.

2. The insulated bearing according to claim 1, wherein, The insulating layer (6) is formed by a polymer, and the polymer is polyphenylene sulfide or aromatic nylon.

3. The insulating bearing according to claim 1, wherein, The insulating layer (6) is formed by a polymer alloy, and the polymer alloy includes a continuous phase and a dispersed phase. Preferably, the continuous phase of the polymer alloy is polyphenylene sulfide, or aromatic nylon, or a mixture of polyphenylene sulfide and aromatic nylon; preferably, in the polymer alloy, the content of the continuous phase is 20 - 70 wt%.

4. The insulating bearing according to claim 3, wherein, When the continuous phase includes polyphenylene sulfide, the polyphenylene sulfide is linear polyphenylene sulfide and / or crosslinked polyphenylene sulfide.

5. The insulated bearing according to claim 3, wherein, The dispersed phase is polyphenylene ether; preferably, in the polymer alloy, the content of the dispersed phase is 5 - 25 wt%.

6. The insulated bearing according to claim 2 or 3, wherein The insulating layer (6) further includes glass fiber, and preferably, the glass fiber is E-glass fiber, D-glass fiber, and / or quartz glass fiber; more preferably, in the insulating layer (6), the content of the glass fiber is 20 - 60 wt%.

7. The insulated bearing according to claim 2 or 3, wherein, The insulating layer (6) further includes a heat-conducting material, and preferably, the heat-conducting material is one or more of hexagonal boron nitride, Al2O3, AlN, BeO, Si3N4, MgO, and SiO2; more preferably, in the insulating layer (6), the content of the heat-conducting material is 20 - 60 wt%.

8. The insulated bearing according to claim 1, wherein, The insulating layer is formed by a polymer alloy, and the polymer alloy includes 20 - 70 wt% of a continuous phase, 5 - 25 wt% of a dispersed phase, 20 - 60 wt% of glass fiber, and the balance is a heat-conducting material; Preferably, the continuous phase is polyphenylene sulfide, or aromatic nylon, or a mixture of polyphenylene sulfide and aromatic nylon; Preferably, the dispersed phase is polyphenylene ether; Preferably, the glass fiber is E-glass fiber, D-glass fiber, and / or quartz glass fiber; Preferably, the heat-conducting material is one or more of hexagonal boron nitride, Al2O3, AlN, BeO, Si3N4, MgO, and SiO2.

9. The insulated bearing according to any one of claims 1-8, wherein, The body (1) further includes: A raceway (2); An axial end face (3); A radial outer peripheral face (4), which is arranged to face away from the raceway (2) in the radial direction; Wherein, a material removal part is included on the surface of the body (1), and the insulating layer (6) is coated and molded on the body (1) and molded into the material removal part; Preferably: The body (1) includes an axial flange (5), which protrudes axially outward relative to the axial end face (3), and a chamfered part (54) as the material removal part at the intersection between the radial outer peripheral face (4) and the axial flange (5); or The body (1) further includes a chamfered part as the material removal part provided at the intersection between the radial outer peripheral face (4) and the axial end face (3).

10. A manufacturing method of an insulating bearing according to any one of claims 1 - 9, including: Set the gate of the injection molding machine used for overmolding the insulating layer so that the weld line of the insulating layer (6) after overmolding avoids the main stress-bearing area of the insulating ferrule and / or is formed at the position where the thickness of the insulating layer (6) is the largest.

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