Rolling bearing with integrated fiber optic sensor

Abstract

The present invention provides a rolling bearing, comprising a first ring (14), a second ring (12) and at least one row of rolling elements (16) arranged between the first ring and the second ring. Each of the first and second rings is provided with an inner hole (14a, 12a), an outer surface (14b, 12b) and at least one row of raceways (42, 32) for the at least one row of rolling elements formed on one of the inner hole and the outer surface. The first ring (14) comprises at least one partial ring (36) for defining the raceway and at least one sleeve (40) that can be reliably fixed on the partial ring. The sleeve (40) at least partially defines the other of the inner hole and the outer surface of the first ring. The rolling bearing further comprises at least one optical fiber sensor (24) mounted in at least one circumferential groove (46) formed on the first ring and passing through at least one optical fiber sensor channel (50) opened in the circumferential groove.

Description

Technical Field

[0001] The present invention relates to condition monitoring of rolling bearings, in particular to load sensing.

[0002] In particular, the present invention relates to a rolling bearing with an integrated optical fiber sensor. Background Art

[0003] In order to evaluate the loads carried by rolling bearings, it is known to integrate strain sensors on the fixed (stationary) ring of the bearing.

[0004] Another known method for measuring different parameters of rolling bearings and monitoring their condition in a reliable manner without any local power supply is to use optical fiber sensors. For example, see patent EP2507603B1 (SKF).

[0005] The optical fiber sensor can be arranged in circumferential grooves formed on the outer surface of the non-rotating outer ring. The outer ring is also provided with a channel for the optical fiber to enter and exit. Generally speaking, such a channel has a complex shape, for example, similar to a curve shape.

[0006] Conventionally, the grooves and fiber optic sensor channels are formed by machining on the heat-treated outer ring of the bearing.

[0007] The main disadvantage of this approach is its operating cost, as the tiny milling tool requires a long machining time. For example, the machining time for a single fiber optic sensor channel can take several hours. Summary of the invention

[0008] An object of the present invention is to overcome the above-mentioned disadvantages.

[0009] In one embodiment, the rolling bearing comprises a first ring, a second ring and at least one row of rolling elements arranged between the first and second rings.

[0010] Each of the first and second rings is provided with an inner hole, an outer surface, and at least one row of raceways for the at least one row of rolling elements formed on one of the inner hole and the outer surface.

[0011] According to a common feature, the first ring comprises at least one part ring defining the raceway formed on one of the inner hole and the outer surface. The first ring further comprises at least one sleeve capable of being securely fixed to the part ring, the sleeve at least partially defining the other of the inner hole and the outer surface of the first ring. The sleeve is made of a softer material than the part ring.

[0012] According to another general feature, the rolling bearing further comprises at least one optical fiber sensor, the sensor being mounted in at least one circumferential groove formed on the first ring and passing through at least one optical fiber sensor channel opening in the circumferential groove. At least the optical fiber sensor channel is formed on the sleeve of the first ring.

[0013] With such an arrangement, complex machining of the fiber optic sensor channel (e.g. with a curved shape) can be performed on the soft sleeve. If the soft sleeve can be made of, for example, a plastic material by molding, then the fiber optic sensor channel can also be obtained by molding. Additive manufacturing (commonly known as "3D printing") can also be used to obtain the sleeve.

[0014] Apart from the above, the performance of the bearing does not change compared to a conventional bearing, since the partial ring defining the raceway of the first ring is still made of hard material.

[0015] Advantageously, the sleeve and the partial ring of the first ring are mounted in radial contact with each other.

[0016] The optical fiber sensor is located between the sleeve and the partial ring of the first ring in the radial direction. Therefore, the optical fiber sensor is located in the first ring.

[0017] In one embodiment, the circumferential groove may be formed on an inner hole or an outer surface of the sleeve mounted in contact with the partial ring in a radial direction.

[0018] In another embodiment, the circumferential groove may be formed on the inner hole or outer surface of the sleeve which is not mounted in radial contact with the partial ring. In this embodiment, the circumferential groove may be filled with a potting resin.

[0019] In the above two embodiments, the optical fiber sensor channel and the circumferential groove are both arranged on the sleeve, which again promotes the convenience of production operations. The extension of the optical fiber sensor channel can originate from a positive surface of the sleeve (see the following description for details).

[0020] Alternatively, the circumferential groove may be formed on the inner bore or outer surface of the partial ring mounted in radial contact on the sleeve.

[0021] The fiber optic sensor can therefore be arranged deeper in the rolling bearing in areas of higher stress, which results in a higher sensitivity of the measurement result.

[0022] Advantageously, the axial position of the circumferential groove on the sleeve or partial ring is such that it is located exactly on the line connecting the contact points between the rolling element row and the raceways of the first and second rings, considering a radial plane of the bearing (see below for details).

[0023] Thus, the fiber optic sensor can be located along the line where the combined load is transferred from one raceway to another.

[0024] In one embodiment, the first ring comprises at least two partial rings mounted in contact with each other in the axial direction. In this case, the partial rings are split into juxtaposed ring segments.

[0025] Advantageously, in such an embodiment, the sleeve holds the partial turns of the first turn together. Thus, the sleeve is used to lock the partial turns together without the need for additional drilling and bolting.

[0026] The rolling bearing may comprise at least two rows of rolling elements arranged between the first and second rings, the partial rings of the first ring defining a raceway for each of the two rows of rolling elements.

[0027] In a specific embodiment, the sleeve of the first ring is provided with at least one protrusion protruding radially toward the second ring, and the circumferential groove is formed on the protrusion. Therefore, the optical fiber sensor can also be placed deeper in the rolling bearing in an area with higher stress.

[0028] When the inner ring is a rotating ring, the first ring of the rolling bearing is the outer ring; or when the outer ring is a rotating ring, the first ring of the rolling bearing is the inner ring.

[0029] The invention and its advantages will be better understood by reading the following detailed description of specific embodiments illustrated by way of non-limiting example and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of a rolling bearing according to a first embodiment of the present invention;

[0031] Figure 2 yes Figure 1 A front view of the rolling bearing shown;

[0032] Figure 3 yes Figure 2 A cross-sectional view along III-III;

[0033] Figure 4 yes Figure 3 A partial enlarged view of

[0034] Figure 5 yes Figure 2 Sectional view along VV;

[0035] Figure 6 is a cross-sectional view of a rolling bearing according to a second embodiment of the present invention;

[0036] Figure 7 yes Figure 6 A partial enlarged view of

[0037] Figure 8 is a cross-sectional view of a rolling bearing according to a third embodiment of the present invention;

[0038] Fig. 9 yes Figure 8 A partial enlarged view of

[0039] Fig.10 is a cross-sectional view of a rolling bearing according to a fourth embodiment of the present invention; and

[0040] Fig.11 yes Fig.10 A partial enlarged view of . DETAILED DESCRIPTION

[0041] Figure 1 and Figure 2 The rolling bearing 10 shown in the figure comprises an inner ring 12 and an outer ring 14, wherein the inner and outer rings 12 and 14 are coaxial and extend along the rotation axis XX' ( Figure 3 ) extends in the axial direction.

[0042] Figure 3 It is more clearly shown that the rolling bearing 10 also includes two rows of rolling elements 16 and 18, both provided in the form of balls, arranged between the inner ring 12 and the outer ring 14. The rolling bearing 10 also includes cages 20, 22 for keeping the rolling elements 16, 18 in each row at regular circumferential spacing.

[0043] As will be described later, the rolling bearing 10 further includes two optical fiber sensors 24 , 26 disposed on the outer ring 14 .

[0044] In the above embodiment, the inner ring 12 is formed as a split ring, which is composed of two annular partial rings 28 and 30 mounted in contact with each other in the axial direction. In other words, the inner ring 12 is subdivided into two partial rings 28 and 30 in the axial direction, and the two partial rings 28 and 30 are identical to each other and symmetrical with respect to the radial section passing through the center of the rolling bearing.

[0045] The inner ring 12 includes a cylindrical inner hole 12a and a cylindrical outer surface 12b disposed opposite to the inner hole. The cylindrical outer surface 12b is formed with toroidal circumferential raceways 32, 34 for the rolling elements 16, 18, and the raceways 32, 34 face radially outward. The inner ring 12 further includes two (axially) oppositely disposed positive radially extending positive (the positive direction is Figure 2 (in the viewing direction, the same below) side surfaces 12c and 12d, which define the inner hole 12a and the outer surface 12b of the inner ring in the axial direction.

[0046] In the above embodiment, the outer ring 14 also includes two annular partial rings 36 and 38. The two partial rings 36 and 38 are mounted in contact with each other in the axial direction. The two partial rings 36 and 38 are identical and symmetrical with respect to the radial section passing through the center of the rolling bearing 10. The partial rings 28, 30 and 36, 38 of the inner and outer rings are made of metal, such as hardened steel. Alternatively, only the raceways provided on the partial rings are hardened.

[0047] The outer ring 14 further comprises an annular sleeve 40 which is independent of the partial rings 36, 38 but is reliably fixed to the latter. The sleeve 40 can be fixed to the partial rings 36, 38 in any suitable manner, for example, by adhesion, ablation, welding, etc.

[0048] The sleeve 40 is mounted around the partial rings 36, 38 in the radial direction and contacts the partial rings 36, 38 in the radial direction. The sleeve 40 covers the partial rings 36, 38 in the radial direction and is mounted on the outer surface of the partial rings 36, 38.

[0049] The outer ring 14 includes a cylindrical inner hole 14a in which two toroidal circumferential raceways 42, 44 for rolling elements 16, 18 are formed, the raceways facing radially inward. The outer ring 14 also includes a cylindrical outer surface 14b disposed radially opposite to the inner hole 14a.

[0050] The outer ring 14 further includes two (in the axial direction) oppositely arranged positive side surfaces 14c and 14d extending in the radial direction, which define the inner hole 14a and the outer surface 14b of the outer ring in the axial direction. The side surface 14d of the outer ring is in the same plane (coplanar) with the side surface 12d of the inner ring, and the side surface 14c of the outer ring is in the same plane (coplanar) with the side surface 12c of the inner ring.

[0051] The inner bore 14a and raceways 42, 44 of the outer ring are formed by the partial rings 36, 38. The outer surface 14b of the outer ring is formed by the sleeve 40. The side surface 14c of the outer ring is formed by the partial ring 36 and the sleeve 40. Similarly, the side surface 14d of the outer ring is formed by the partial ring 38 and the sleeve 40.

[0052] The sleeve 40 comprises a cylindrical inner hole and a cylindrical outer surface arranged opposite to the inner hole. The inner hole of the sleeve is mounted in contact with the outer surfaces of the partial rings 36 and 38 in the radial direction, and the outer surface of the sleeve forms the outer surface 14b of the outer ring. The sleeve 40 also comprises two oppositely arranged positive side surfaces extending in the radial direction, which define the inner hole and the outer surface of the sleeve in the axial direction. The side surfaces 14c, 14d of the outer ring are respectively partially formed by these side surfaces of the sleeve.

[0053] As mentioned above, two optical fiber sensors 24 and 26 are disposed on the outer ring 14 . Figure 4 It is more clearly shown that two circumferential grooves 46, 48 are formed on the inner hole of the sleeve 40, and the optical fiber sensors 24, 26 are respectively installed in the circumferential grooves 46, 48.

[0054] In the above-mentioned embodiment, the circumferential grooves 46 and 48 have an annular shape. Alternatively, the circumferential grooves 46 and 48 may not be annular. For example, the circumferential grooves 46 and 48 may extend within an angular sector of no more than 340 degrees.

[0055] The groove 46 radially surrounds the partial ring 36, and the groove 48 radially surrounds the partial ring 38. The grooves 46 and 48 are covered by the partial rings 36 and 38. The axial position of the groove 46 in the inner hole of the sleeve 40 is located just on the line (not shown) of the contact points between the rolling element 16 and the inner and outer ring raceways 32 and 42 in a radial plane of the bearing, so that the load of the bearing can be transferred from one raceway to another along the line (the radial plane is an imaginary radial plane of the bearing, and the contact point line is just located in this plane).

[0056] Similarly, the axial position of the groove 48 in the inner hole of the sleeve 40 is such that it is located just on the line connecting the contact points between the rolling element 18 and the inner and outer ring raceways 34 and 44 in the radial plane.

[0057] The thickness of the sleeve 40 is defined to enable the fiber optic sensors 24 and 26 to be located at an ideal depth, thereby optimizing the measurement performance. For example, the thickness of the sleeve 40 may be equivalent to 20% to 50% of the overall thickness of the outer ring 14 .

[0058] See again Figure 1The sleeve 40 is also provided with channels 50, 52 for the optical fiber sensor to enter and exit. In the illustrated embodiment, each channel 50, 52 first enters the material layer of the sleeve 40 along the axial direction from one of the positive surfaces, and then opens (exposes) to the outer surface of the sleeve. Figure 5 The channel 50 shown can also be seen.

[0059] On the outer surface of the sleeve 40, the channels 50, 52 each comprise an axial portion followed by a curved portion which in turn is continued by a circumferential portion. The ends of the circumferential portions of the channels 50, 52 radially penetrate into the material layer of the sleeve and open into the corresponding grooves 46, 48.

[0060] The sleeve 40 is made of a softer material than the partial rings 36, 38. For example, the hardness of the sleeve 40 may be lower than 38 Vickers, while the hardness of the partial rings 36, 38 may be at least above 58 Vickers.

[0061] The sleeve 40 can be made of metal, for example, steel or an alloy. Since the sleeve 40 is made of a softer material than the partial rings 36, 38, the machining of the channels 50, 52 with the curved portions becomes easier. This also results in a reduction in the machining time of the grooves 46, 48. Alternatively, the sleeve 40 can also be made of a plastic material. In this case, the channels 50, 52 and the grooves 46, 48 are formed on the sleeve during the molding process of the plastic.

[0062] As described above, each fiber optic sensor 24, 26 is mounted in a corresponding groove 46, 48 formed in the inner hole of the sleeve 40. Each fiber optic sensor 24, 26 is also mounted in a channel 50, 52 formed in the sleeve 40 and opening into the corresponding groove 46, 48.

[0063] Each channel 50, 52 allows the optical fiber sensor 24, 26 to be manually guided when it enters the material layer of the sleeve axially and then tangentially introduced into the corresponding groove 46, 48. After turning a bend and entering the corresponding groove 46, 48, the corresponding optical fiber sensor 24, 26 leaves the groove and is securely fixed in the channel 50, 52.

[0064] Each fiber optic sensor 24, 26 is provided with a plurality of light distorting structures, such as fiber Bragg gratings. For more details on fiber optic sensors, for example, reference can also be made to patent EP2802796B1 (SKF). The fiber optic sensors 24, 26 can be used to measure different parameters of the rolling bearing 10, such as load, temperature, pressure, vibration, etc.

[0065] exist Figure 6 and 7 In the illustrated embodiment, the same components are given the same reference numerals. Unlike the previous embodiment, the inner hole of the sleeve 40 is provided with an annular protrusion 54 extending radially toward a recess (not shown) formed on the outer surface of the partial rings 36, 38, and the circumferential grooves 46, 48 are formed on the inner hole of the protrusion 54. With such a structure, the optical fiber sensors 24, 26 can be placed deeper in the rolling bearing.

[0066] In the foregoing embodiment, the partial rings 28, 36 and 30, 38 are arranged in a back-to-back bearing arrangement; alternatively, the partial rings 28, 36 and 30, 38 may also be arranged in a back-to-back bearing arrangement. Figure 8 and 9 The bearings are arranged in a face-to-face bearing arrangement or in a tandem arrangement as in the embodiment shown in FIG.

[0067] It is conceivable that, with such a face-to-face bearing arrangement, the sleeve 40 may also be provided with two projections extending radially towards the recesses formed on the outer surfaces of the partial rings 36, 38 and having circumferential grooves 46, 48 formed on said projections.

[0068] In the aforementioned embodiments, the outer ring 14 is provided with a sleeve, since the inner ring 12 is the ring intended to be used for rotation.

[0069] Alternatively, when the outer ring 14 is a ring intended for rotation, the inner ring 12 may be provided with a sleeve 40, such as Fig.10 and 11 Detailed description of the invention The same embodiments are shown in FIG. 2 , wherein the same components are given the same reference numerals.

[0070] In this embodiment, the sleeve 40 is installed in the inner holes of the partial rings 28 and 30. The outer surface of the sleeve 40 is installed in contact with the inner holes of the partial rings 28 and 30 in the radial direction. Circumferential grooves 46 and 48 are formed on the outer surface of the sleeve 40. Channels 50 and 52 for the optical fiber sensor to enter and exit the sleeve 40 axially from a positive surface of the sleeve 40 into the material layer of the sleeve and are open (exposed) on the inner hole of the sleeve. Each channel 50 and 52 extends along the inner hole of the sleeve 40 in the axial and circumferential directions, is immersed in the material layer of the sleeve in the radial direction, and opens to the corresponding groove 46 and 48.

[0071] In this embodiment, the partial rings 28, 36 and 30, 38 are arranged in a face-to-face bearing arrangement. Alternatively, the partial rings 28, 36 and 30, 38 can also be arranged in a back-to-back bearing arrangement or a tandem arrangement. The outer surface of the sleeve 40 can also be provided with one or two protrusions, which protrude radially outward and enter the recess formed on the inner hole of the partial rings 28, 30, and the circumferential grooves 46, 48 are formed on the protrusions.

[0072] In the above-described embodiment, the sleeve 40 extends over the entire length of the corresponding partial coil. Alternatively, the sleeve 40 may also have only a shortened length.

[0073] In the above-described embodiment, the grooves 46, 48 and the channels 50, 52 are all provided on the sleeve 40. Alternatively, only the channels 50, 52 (having the curved portion) are provided on the sleeve 40. In this case, the grooves 46, 48 are formed on the partial ring of the outer ring 14 or the inner ring 12. Thus, the corresponding optical fiber sensors 24, 26 can be placed deeper in the region with higher stress in the rolling bearing.

[0074] The invention is described on the basis of a rolling bearing in which the inner and outer rings are arranged to have two annular partial rings mounted in contact with each other in the axial direction. Alternatively, the inner and / or outer rings may comprise only one partial ring, or three or more partial rings.

[0075] In the illustrated embodiment, the rolling bearing comprises two rows of rolling elements. Alternatively, the rolling bearing may also comprise only one row of rolling elements, or may comprise three or more rows of rolling elements. In the illustrated embodiment, the rolling elements are spheres (balls). Alternatively, the rolling bearing may also comprise other types of rolling elements, such as rollers. In the disclosed embodiment, the rolling bearing is suitable for carrying both axial loads and radial loads. Alternatively, the rolling bearing may also be suitable for carrying only axial loads or radial loads.

Claims

1. A rolling bearing, comprising a first ring (14), a second ring (12) and at least one row of rolling elements (16) arranged between the first ring and the second ring, wherein the first ring (14) is provided with a first inner hole (14a), a first outer surface (14b) and at least one row of raceways (42) formed on one of the first inner hole and the first outer surface for the at least one row of rolling elements, and the second ring (12) is provided with a second inner hole (12a), a second outer surface (12b) and at least one row of raceways (32) formed on one of the second inner hole and the second outer surface for the at least one row of rolling elements, characterized in that: The first ring (14) comprises at least one partial ring (36, 38) for defining the raceway and at least one sleeve (40) that can be reliably fixed on the partial ring, the sleeve (40) at least partially defining the other of the first inner hole and the first outer surface, and the sleeve (40) is made of a material softer than the partial ring (36, 38); The rolling bearing further comprises at least one optical fiber sensor (24), which is installed in at least one circumferential groove (46) formed on the first ring and passes through at least one optical fiber sensor channel (50) opened in the circumferential groove. At least the optical fiber sensor channel (50) is formed on the sleeve of the first ring and includes an axial portion connected to each other, a curved portion, and a circumferential portion whose end is opened in the circumferential groove (46) to allow the optical fiber sensor (24) to enter and exit.

2. The rolling bearing according to claim 1, characterized in that: The sleeve (40) and the partial rings (36, 38) of the first ring are mounted in radial contact with each other.

3. The rolling bearing according to claim 2, characterized in that: The optical fiber sensor (24) is arranged radially between the sleeve (40) of the first ring and the partial rings (36, 38).

4. The rolling bearing according to claim 2 or 3, characterized in that: The circumferential groove (46) is formed on the inner hole or outer surface of the sleeve (40) mounted in contact with the partial rings (36, 38) in the radial direction.

5. The rolling bearing according to claim 2 or 3, characterized in that: The circumferential groove (46) is formed on the inner hole or outer surface of the partial ring (36, 38) mounted on the sleeve (40) in radial contact.

6. The rolling bearing according to claim 1 or 2, characterized in that: The circumferential groove (46) is formed on the inner hole or outer surface of the sleeve (40) which is mounted without contacting the partial rings (36, 38) in the radial direction.

7. The rolling bearing according to any one of claims 1 to 3, characterized in that: Considering a radial plane of the bearing, the axial position of the circumferential groove (46) on the sleeve (40) or the partial ring (36, 38) is such that it is located exactly on the line connecting the contact points between the row of rolling elements (16) and the raceway (42) of the first ring and the raceway (32) of the second ring.

8. The rolling bearing according to any one of claims 1 to 3, characterized in that: The first ring (14) comprises at least two partial rings (36, 38) mounted in contact with each other in the axial direction, and the sleeve (40) holds the partial rings (36, 38) together; The rolling bearing further comprises at least two rows of rolling elements (16, 18) arranged between the first ring (14) and the second ring (12), and the partial rings (36, 38) of the first ring respectively define a raceway (42, 44) for each row of rolling elements in the at least two rows of rolling elements.

9. The rolling bearing according to any one of claims 1 to 3, characterized in that: The sleeve (40) of the first ring (14) is provided with at least one protrusion (54) protruding radially toward the second ring (12), and the circumferential groove (46) is formed on the protrusion (54).

10. The rolling bearing according to any one of claims 1 to 3, characterized in that: An axial portion of the fiber optic sensor channel (50) extends from the forward surface of the sleeve.

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