JP2021185318A - Rolling bearing device - Google Patents

Abstract

To provide a rolling bearing device with a sensor which can satisfy both requirements of assembling performance and durability.SOLUTION: A rolling bearing device comprises: a rolling bearing having an outer ring having an outer ring raceway at an internal peripheral face, an inner ring having an inner ring raceway at an external peripheral face, and a plurality of rolling bodies interposed between the outer ring raceway and the inner ring raceway; and a sensor for detecting a state of the rolling bearing. At least one peripheral face of the external peripheral face of the outer ring or the internal peripheral face of the inner ring is provided with a groove for accommodating the sensor so as not to protrude from the peripheral face. The groove has a bottom face and a pair of sidewall regions which face each other in a prescribed direction including at least one of an axial direction and a peripheral direction of the rolling bearing. The sensor is fixed to a pair of the sidewall regions by welding with a clearance between the bottom face and the rolling bearing in a radial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rolling bearing device.

A technique of attaching a strain sensor to a rolling bearing to detect the state of the rolling bearing is known. For example, Patent Document 1 and Patent Document 2 disclose a bearing with a sensor in which a strain sensor is arranged in a groove provided on an outer peripheral surface of an outer ring. Further, Patent Document 3 discloses a bearing for a wheel with a sensor including a sensor mounting member attached to the outer member and a sensor unit having a strain sensor attached to the sensor mounting member. Patent Document 3 discloses an example in which the strain sensor is fixed to the sensor mounting member by adhesion and an example in which the strain sensor is formed by printing and firing on the surface of the sensor mounting member (paragraph 0050, FIG. 10, etc.).

Japanese Unexamined Patent Publication No. 2017-44312 Japanese Unexamined Patent Publication No. 2007-32705 Japanese Unexamined Patent Publication No. 2007-239848

Rolling bearings equipped with a contact-type sensor are required to have the same assembling property and durability as rolling bearings without a sensor. Assembling means the ease of assembling the rolling bearing to the housing or the rotating shaft. In order to improve the assembling property, for example, a groove is provided on the peripheral surface of the rolling bearing (the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring), and a sensor is mounted in the groove so as not to protrude from the groove. It is conceivable to do.

FIG. 10 is a cross-sectional view illustrating a problem according to the present invention. A contact type sensor 94 is mounted on the rolling bearing 9 according to FIG. 10. The rolling bearing 9 has an outer ring 91 made of metal, an inner ring 92, and a plurality of rolling elements 93, respectively. The outer ring 91 is an annular member, and an outer ring track 91a1 is formed on the inner peripheral surface 91a of the outer ring 91, and a groove portion 91c in which the sensor 94 is housed is formed on the outer peripheral surface 91b of the outer ring 91. Further, a housing 98 indicated by a two-dot chain line is attached to the outer peripheral surface 91b side of the outer ring 91.

The inner ring 92 is an annular member, and a rotation shaft (not shown) is attached to the inner peripheral surface 92a side of the inner ring 92, and an inner ring track 92b1 is formed on the outer peripheral surface 92b of the inner ring 92. The plurality of rolling elements 93 are housed in the space between the outer ring track 91a1 and the inner ring track 92b1 at a distance in the circumferential direction by a cage (not shown).

The sensor 94 is, for example, a sensor that detects distortion. The sensor 94 has an intermediate member 95 made of a thin metal plate, a strain gauge 96 for detecting strain, and a wiring 97 for taking out a detection signal of the strain gauge 96 to the outside. The intermediate member 95 is joined to the bottom surface of the groove portion 91c by welding. The intermediate member 95 has elasticity and elastically deforms according to the strain on the bottom surface of the groove portion 91c, thereby functioning as a "strain transmission member" that transmits the strain on the rolling bearing 9 side to the strain gauge 96.

Here, the depth of the groove 91c is set deeper than the height of the sensor 94. Therefore, the sensor 94 is completely housed in the groove portion 91c without protruding outward in the radial direction from the outer peripheral surface 91b. As a result, when the outer peripheral surface 91b of the outer ring 91 is attached to the housing 98, it is possible to prevent the sensor 94 from interfering with the housing 98, and it is possible to secure the same assembling property as the rolling bearing without the sensor.

Further, the sensor 94 is joined to the bottom surface of the groove portion 91c by welding. In particular, since the intermediate member 95 and the outer ring 91 are made of metal, the sensor 94 is attached to the rolling bearing 9 by directly joining the metal members by welding, as compared with the case of joining using an adhesive such as resin, for example. Can be firmly joined.

On the other hand, when joining by welding, it is necessary to melt a part of the outer ring 91 by heating, and the region R9 including the melted part of the outer ring 91 and its periphery is heated to a temperature higher than the quenching temperature of the outer ring 91. .. As a result, the strength of the region R9 is lower than that before welding.

In particular, the groove portion 91c is located at the center of the rolling bearing 9 in the axial direction (X direction in FIG. 10), and the outer ring track 91a1 is located inward in the radial direction of the groove portion 91c. Therefore, if the radial distance D9 from the position where the region R9 is formed to the outer ring track 91a1 is short, the rolling bearing 9 breaks between the bottom surface of the groove 91c and the outer ring track 91a1 when a large load is applied. May occur.

Therefore, in order to increase the durability of the rolling bearing 9, it is necessary to make the distance D9 longer. However, if the depth of the groove 91c is made shallower in order to lengthen the distance D9, the sensor 94 protrudes radially outward from the outer peripheral surface 91b, and the assembling property is deteriorated. As described above, the rolling bearing 9 equipped with the sensor 94 could not meet the requirements for both assembling property and durability.

Therefore, an object of the present invention is to provide a rolling bearing device with a sensor that can meet the requirements of both assembling property and durability.

(1) The rolling bearing device according to the present invention includes an outer ring having an outer ring track on the inner peripheral surface, an inner ring having an inner ring track on the outer peripheral surface, and a plurality of rolling elements interposed between the outer ring track and the inner ring track. A rolling bearing having a A groove is formed to accommodate the rolling bearing so as not to protrude, and the groove has a bottom surface and a pair of side wall regions facing in a predetermined direction including at least one of the axial direction and the circumferential direction of the rolling bearing, and the sensor is a sensor. , A rolling bearing device, each of which is fixed to a pair of side wall regions by welding with a gap between the bottom surface and the rolling bearing in the radial direction.

Since the sensor according to the present invention is housed in the groove so as not to protrude from the peripheral surface, it is possible to prevent interference between the sensor and the housing, and to ensure the same level of assembling property as a rolling bearing without a sensor. can. Further, since the sensor is fixed to the side wall region by welding, the welding position can be set to the peripheral surface side with respect to the bottom surface. This makes it possible to increase the distance between the outer ring track and the region where the strength can be weakened by welding, as compared with the case where the sensor is fixed to the bottom surface by welding. As a result, it is possible to prevent the durability of the rolling bearing from being lowered due to welding of the sensor. As described above, according to the rolling bearing device according to the present invention, it is possible to secure the same level of assembling property and durability as a rolling bearing without a sensor, and both assembling property and durability are required. Can respond to.

(2) Preferably, the sensor has a strain gauge for detecting strain and an intermediate member for transmitting the strain of the rolling bearing to the strain gauge, and the intermediate member is provided in each of the pair of side wall regions. It is fixed by welding, and the strain gauge is fixed to the bottom surface side of the intermediate member.

With this configuration, even if it is difficult to directly join the strain gauge to the side wall region, an intermediate member that can be easily joined to both the strain gauge and the side wall region is used as a buffer. , The strain gauge can be indirectly joined to the sidewall region. Further, by arranging the intermediate member to be welded to the side wall region on the peripheral surface side as much as possible and fixing the strain gauge on the bottom surface side thereof, it is possible to secure a longer distance between the welded region and the outer ring track. can. As a result, it is possible to further suppress a decrease in the durability of the rolling bearing device.

(3) Preferably, the sensor has a fixing portion for fixing the strain gauge to the bottom surface side of the intermediate member, and the fixing portion has a central portion of the strain gauge and the bottom surface side of the intermediate member. At least two points of the strain gauge located across the central portion of the strain gauge are fixed to the bottom surface side of the intermediate member in a non-fixed state.

With this configuration, the stress generated in the fixed portion can be reduced as compared with the case where the strain gauge and the intermediate member are completely fixed. This makes it possible to increase the durability of the fixed portion. Further, when the intermediate member is distorted, the central portion of the strain gauge is pulled by the fixing portion located across the central portion. As a result, the strain gauge can follow and deform the intermediate member more accurately, and the strain gauge can detect the strain with high sensitivity.

(4) Preferably, a wiring for taking out the detection signal of the sensor to the outside of the rolling bearing is further provided, and the wiring is fixed to the bottom surface side of the sensor.

With this configuration, the wiring can be accommodated in the gap between the sensor and the bottom surface, so that more elements can be accommodated in the groove while the position where the sensor is welded is further away from the outer ring track. ..

(5) Preferably, the wiring for taking out the detection signal of the sensor to the outside of the rolling bearing is further provided, and the wiring is fixed to the peripheral surface side of the strain gauge so as not to protrude from the peripheral surface. ..

With such a configuration, the thickness of the sensor and the wiring in the radial direction can be further reduced. As a result, the depth of the groove required for accommodating the sensor and the wiring can be made shallow, and the deterioration of the durability of the rolling bearing can be suppressed more reliably.

(6) Preferably, the bottom surface intersects a virtual straight line passing through a first point where the rolling element is in contact with the outer ring track and a second point where the rolling element is in contact with the inner ring track, and the pair of side wall regions is formed. , A virtual intersection where the bottom surface and the virtual straight line intersect is sandwiched in the predetermined direction.

Here, the distortion of the portion of the outer ring including the virtual intersection tends to be larger than the distortion of the other portion of the outer ring. Therefore, according to the configuration of (6) above, the sensor fixed to the side wall region can be expanded or contracted more greatly. As a result, the sensor can generate a larger distortion, and the sensor can detect the distortion more sensitively.

(7) Preferably, the side wall region includes a stepped surface facing the radial direction including the outer side, and the sensor is fixed to the stepped surface by welding. With this configuration, the sensor can be placed still on the step surface. This makes it easier to aim, for example, when irradiating a laser for welding from the outside in the radial direction, so that the sensor can be more easily fixed to the side wall region.

(8) Preferably, the side wall region includes a side surface facing the predetermined direction, and the sensor is fixed to the side surface by welding. With this configuration, the region of the side wall region that is heated above the quenching temperature by welding can be further separated from the outer ring track. As a result, it is possible to more reliably suppress the deterioration of the durability of the rolling bearing.

According to the present invention, it is possible to provide a rolling bearing device with a sensor that can meet the requirements of both assembling property and durability.

It is a side view of the rolling bearing apparatus which concerns on embodiment. FIG. 3 is a cross-sectional view partially showing a cross section in a ZX plane in which a rolling bearing device is cut by the cutting line of arrow II in FIG. 1. It is a top view which partially shows the rolling bearing apparatus seen from the arrow III of FIG. It is sectional drawing which shows the detection part which concerns on the 1st modification. It is sectional drawing which shows the detection part which concerns on the 2nd modification. It is sectional drawing which shows the detection part which concerns on the 3rd modification. It is explanatory drawing of the detection part which concerns on 4th modification. It is explanatory drawing of the detection part which concerns on 4th modification. It is explanatory drawing of the detection part which concerns on 4th modification. It is sectional drawing explaining the subject which concerns on this invention.

<Embodiment>
Hereinafter, the rolling bearing device according to the embodiment of the present invention will be described with reference to the drawings. In each drawing, an XYZ Cartesian coordinate system is appropriately shown in order to clarify the positional relationship of the rolling bearing device.

<Structure of rolling bearing device>
FIG. 1 is a side view of the rolling bearing device 1 according to the embodiment. The rolling bearing device 1 includes a rolling bearing 2 and a detection unit 3. The rolling bearing 2 has an outer ring 21, an inner ring 22, a plurality of rolling elements 23, and a cage (not shown) for holding the rolling elements 23.

In the present disclosure, the direction along the center line C1 of the rolling bearing 2 (hereinafter referred to as "bearing center line C1") is the axial direction of the rolling bearing 2, and is simply referred to as "axial direction". The axial direction also includes a direction parallel to the bearing center line C1 (X direction in FIG. 1). The paper side of FIG. 1 is defined as one side in the axial direction, and the depth side of FIG. 1 is defined as the other side in the axial direction. The direction orthogonal to the bearing center line C1 is the radial direction of the rolling bearing 2, and is simply referred to as the "diameter direction". The direction in which the rolling bearing 2 (inner ring 22 in the first embodiment) rotates about the bearing center line C1 is the circumferential direction of the rolling bearing 2, and is simply referred to as the "circumferential direction".

FIG. 2A is a cross-sectional view partially showing a cross section in a ZX plane in which the rolling bearing device 1 is cut by the cutting line of arrow II in FIG. FIG. 2B is an enlarged view showing only a portion of the groove portion 24 described later in FIG. 2A. FIG. 3 is a plan view partially showing the rolling bearing device 1 as seen from the arrow III of FIG. In FIGS. 2 and 3, the X direction corresponds to the axial direction, the Y direction corresponds to the circumferential direction, and the Z direction corresponds to the radial direction.

See FIG. 2 (a). The outer ring 21 is an annular fixed ring and has an inner peripheral surface 21a and an outer peripheral surface 21b. An outer ring track 21a1 recessed outward in the radial direction is formed on the inner peripheral surface 21a of the outer ring 21. The outer peripheral surface 21b side of the outer ring 21 is fixed to the housing 7 indicated by the alternate long and short dash line. Further, a groove portion 24 recessed on the outer ring track 21a1 side is formed on the outer peripheral surface 21b of the outer ring 21. A detection unit 3 is mounted in the groove portion 24.

Since the portion of the detection unit 3 located on the outermost side in the radial direction (intermediate member 41 described later) is located inward in the radial direction from the outer peripheral surface 21b, the detection unit 3 has a diameter from the groove portion 24 to the outer peripheral surface 21b. Does not protrude outward in the direction. This makes it possible to prevent the detection unit 3 from interfering with the housing 7 when the rolling bearing 2 is mounted on the housing 7. As a result, the assembling property of the rolling bearing 2 can be ensured to the same level as that of the rolling bearing in which the detection unit 3 is not provided.

The inner ring 22 is an annular rotating ring and has an inner peripheral surface 22a and an outer peripheral surface 22b. The inner peripheral surface 22a side of the inner ring 22 is fixed to a rotation shaft (not shown). An inner ring track 22b1 recessed inward in the radial direction is formed on the outer peripheral surface 22b of the inner ring 22.

The plurality of rolling elements 23 roll on the outer ring orbit 21a1 and the inner ring orbit 22b1 in a state where the outer ring orbit 21a1 of the outer ring 21 and the inner ring orbit 22b1 of the inner ring 22 are in point contact with each other. That is, the outer ring track 21a1 and the inner ring track 22b1 are runways on which a plurality of rolling elements 23 roll.

The shape of the inner ring 22 is not limited to an annular shape, and may be, for example, an inner shaft having a solid structure (for example, a hub shaft). Further, the outer ring 21 may be a rotating wheel and the inner ring 22 may be a fixed ring. The plurality of rolling elements 23 are balls in this embodiment. The plurality of rolling elements 23 may be "rollers". The rolling bearing 2 of the present embodiment is a single row type, but may be a double row type.

Further, although the groove portion 24 according to the present embodiment is formed on the outer peripheral surface 21b of the outer ring 21, it may be formed on the inner peripheral surface 22a of the inner ring 22. In this case, the detection unit 3 is mounted in the groove portion 24 on the inner ring 22 side. Of the outer peripheral surface 21b of the outer ring 21 or the inner peripheral surface 22a of the inner ring 22, the surface on which the groove portion 24 is formed is simply referred to as a “peripheral surface” as appropriate.

The point where one rolling element 23 touches the outer ring track 21a1 at a certain point in time is referred to as a "first point P1". Further, the point where the rolling element 23 touches the inner ring track 22b1 at that time point is referred to as a "second point P2". A virtual straight line passing through the first point P1 and the second point P2 is referred to as a "virtual straight line VL1". The virtual straight line VL1 passes through the center C2 of the rolling element 23.

See FIG. 2 (b). In FIG. 2B, the detection unit 3 and the hatching are not shown. The groove portion 24 has a bottom surface 25 and a pair of side wall regions 26. The bottom surface 25 is a surface of the groove 24 located closest to the outer ring track 21a1. The bottom surface 25 is orthogonal to the virtual straight line VL1. The intersection of the bottom surface 25 and the virtual straight line VL1 is referred to as a "virtual intersection P3". The pair of side wall regions 26 are located on the outer peripheral surface 21b (peripheral surface) side of the bottom surface 25, respectively, and are a pair of regions facing the rolling bearing 2 in the axial direction. Further, the pair of side wall regions 26 are located so as to sandwich the virtual intersection P3 in the axial direction.

The direction in which the pair of side wall regions 26 face each other is not limited to the axial direction. For example, the pair of side wall regions 26 may face the circumferential direction of the rolling bearing 2, or may have directions inclined with respect to the axial direction or the circumferential direction of the rolling bearing 2, respectively (both the axial component and the circumferential component). It may face in the direction including). That is, the pair of side wall regions 26 face each other in a predetermined direction including at least one of the axial direction and the circumferential direction of the rolling bearing 2.

The pair of side wall regions 26 have a first side surface 261 and a step surface 262 and a second side surface 263, respectively. The pair of first side surfaces 261 and the pair of second side surfaces 263 are side surfaces facing in the axial direction (predetermined direction), respectively. In other words, the direction in which the normals of the pair of first side surfaces 261 and the pair of second side surfaces 263 extend coincides with the axial direction. The first side surface 261 is connected to the bottom surface 25 inward in the radial direction. That is, the first side surface 261 is a side surface extending radially outward from both ends in the axial direction of the bottom surface 25. The pair of first side surfaces 261 face each other with a width W1 in the axial direction about the virtual intersection P3.

The second side surface 263 is connected to the outer peripheral surface 21b on the outer side in the radial direction. That is, the second side surface 263 is a side surface extending inward in the radial direction from the inner side in the axial direction of the outer peripheral surface 21b. The pair of second side surfaces 263 face each other with a width W2 larger than the width W1 in the axial direction around the virtual intersection P3.

Each of the pair of stepped surfaces 262 is a stepped surface facing outward in the radial direction. The inside of the step surface 262 in the axial direction is connected to the first side surface 261. Further, the outer side of the step surface 262 in the axial direction is connected to the second side surface 263. In other words, the pair of second side surfaces 263 and the pair of stepped surfaces 262 form the first groove portion (first step groove), and the pair of first side surface 261 and the bottom surface 25 form the second groove portion deeper than the first groove portion. A groove (second-stage groove) is formed.

The step surface 262 may face in a direction including the radial outer direction. For example, the step surface 262 may face in a direction including both radial outer and axial inner components. However, in order to allow the intermediate member 41 described later to rest more accurately on the step surface 262, it is preferable that the step surface 262 faces only outward in the radial direction.

As shown in FIG. 1, the groove portion 24 according to the present embodiment is formed over the entire circumference of the outer peripheral surface 21b of the outer ring 21. With this configuration, the shape of the rolling bearing 2 becomes uniform in the circumferential direction, so that it is possible to reduce the bias of the load applied to the housing or the like when the rolling bearing 2 rotates. The groove portion 24 may not be formed over the entire circumference of the outer peripheral surface 21b, but may be formed only at a position where, for example, the detection portion 3 is provided.

See FIG. 2 (a). The detection unit 3 has a sensor 40 and a wiring 61. The sensor 40 is a sensor that detects the state of the rolling bearing 2 (that is, an element that converts the state into an electric signal), and in the present embodiment, detects the distortion of the rolling bearing 2. The sensor 40 may be a sensor (for example, a thermocouple) that detects the temperature of the rolling bearing 2. The sensor 40 is fixed to the pair of side wall regions 26 by welding with a gap between the bottom surface 25 and the rolling bearing 2 in the radial direction.

The sensor 40 has an intermediate member 41, a strain gauge 42, and a fixing portion 43. The intermediate member 41 is located on the outermost peripheral surface 21b side of the sensor 40. The strain gauge 42 is located on the bottom surface 25 side of the sensor 40 with a gap from the bottom surface 25. The wiring 61 is located in the gap. The fixing portion 43 is located between the intermediate member 41 and the strain gauge 42 in the radial direction.

The intermediate member 41 is a plate-shaped metal (for example, copper) that is thin in the radial direction and has a rectangular shape (for example, a rectangular shape) in the axial direction and the circumferential direction. The intermediate member 41 has elasticity in the axial direction and the circumferential direction, and elastically deforms according to the strain of the rolling bearing 2, thereby transmitting the strain of the rolling bearing 2 to the strain gauge 42. The intermediate member 41 is fixed to the pair of side wall regions 26 by welding. More specifically, the intermediate member 41 is fixed to the pair of stepped surfaces 262 by welding.

The axial width of the intermediate member 41 is larger than the width W1 and smaller than the width W2. When fixing the intermediate member 41 to the step surface 262, the intermediate member 41 is made to face each of the pair of step surfaces 262 in the radial direction, and the facing portion is irradiated with a laser from the outside in the radial direction. As a result, the intermediate member 41 and the step surface 262 are melted to form the weld bead 51, and the intermediate member 41 is fixed to the pair of step surfaces 262. As shown in FIG. 3, the weld bead 51 according to the present embodiment is formed so as to extend in the circumferential direction of the intermediate member 41. The weld bead 51 may be formed at each of the four corners of the intermediate member 41 when viewed in an XY plan view.

In addition to the intermediate member 41 and the stepped surface 262, the weld bead 51 may contain a metal material that is a base material of the weld bead 51. For example, in a state where the metal material to be the base material of the weld bead 51 is positioned between the intermediate member 41 and the step surface 262, laser irradiation is performed to melt the intermediate member 41, the step surface 262 and the base material. The weld bead 51 may be formed.

The strain gauge 42 is an element that detects strain as an electric signal by, for example, using a semiconductor (silicon) as a base material and converting strain (displacement amount) into a change in resistance value or the like. The strain gauge 42 detects displacement in at least one of the axial and circumferential directions. The strain gauge 42 includes a detection region for detecting strain and a terminal region for outputting the detection signal obtained in the detection region. A detection region is built in the central portion 42a of the strain gauge 42. Further, the strain gauge 42 is fixed to the bottom surface 25 side (that is, radially inward) of the intermediate member 41 by the fixing portion 43.

The fixed portion 43 is in a state where the central portion 42a of the strain gauge 42 and the bottom surface 25 side of the intermediate member 41 are not fixed, and at least two positions of the strain gauge 42 located across the central portion 42a are intermediate members. It is fixed to the bottom surface 25 side of 41. As shown in FIG. 3, the fixing portion 43 according to the present embodiment fixes the four corners of the strain gauge 42 to the bottom surface 25 side of the intermediate member 41. The fixing portion 43 is made of a metal material (for example, gold) and is formed by, for example, diffusion bonding.

Here, the "non-fixed state" means a state in which the central portion 42a is not directly fixed to the intermediate member 41 by the fixing portion 43. As shown in FIG. 2A, the state in which the central portion 42a and the intermediate member 41 have a radial gap is a non-fixed state. If the strain gauge 42 is fixed to the intermediate member 41 at a position avoiding the central portion 42a, the central portion 42a may be in contact with the intermediate member 41. In this case, when the outer ring 21 is distorted in at least one of the axial direction and the circumferential direction, the intermediate member 41 expands or contracts while sliding in contact with the radial outer surface of the central portion 42a. Such a state is also referred to as a "non-fixed state" with respect to the intermediate member 41. That is, in the "non-fixed state", the central portion 42a and the intermediate member 41 are separated from each other with a gap, and the central portion 42a and the intermediate member 41 are not joined even though there is no gap. And include.

When viewed in an XY plane as shown in FIG. 3, the virtual intersection P3 is located inside the central portion 42a. Further, the virtual intersection P3 is located on the intersection of the diagonal lines of the quadrangle formed by the four fixed portions 43.

See FIG. 2 (a). The wiring 61 is a wiring that takes out the detection signal of the sensor 40 (specifically, the strain gauge 42) to the outside of the rolling bearing 2. The wiring 61 is, for example, a flat cable in which a plurality of cables are bundled in a band shape. The wiring 61 is fixed to the surface of the bottom surface 25 side of the sensor 40 (specifically, the bottom surface 25 side of the strain gauge 42).

See FIG. One end 61a of the wiring 61 is electrically connected to the terminal region of the strain gauge 42. Further, the end portion of the wiring 61 including one end 61a is fixed to the bottom surface 25 side of the strain gauge 42. The other end 61b on the side opposite to one end 61a of the wiring 61 is the other side in the axial direction of the rolling bearing 2 via a portion of the groove portion 24 provided from the central portion in the axial direction to the other side in the axial direction of the outer peripheral surface 21b. Connect with the end of. The detection signal of the sensor 40 is taken out from one end 61a and output to the outside of the rolling bearing 2 (for example, the housing 7) via the other end 61b.

As described above, in the rolling bearing device 1 according to the present embodiment, the outer ring 21 having the outer ring raceway 21a1 on the inner peripheral surface 21a, the inner ring 22 having the inner ring raceway 22b1 on the outer peripheral surface 22b, and the outer ring raceway 21a1 and the inner ring raceway 22b1. A rolling bearing 2 having a plurality of rolling elements 23 interposed between the two, and a sensor 40 for detecting the state of the rolling bearing 2 are provided, and the outer peripheral surface 21b of the outer ring 21 or the inner peripheral surface 22a of the inner ring 22 is provided. A groove 24 for accommodating the sensor 40 so as not to protrude from the peripheral surface is formed on at least one peripheral surface, and the groove portion 24 includes a bottom surface 25 and at least one of the axial direction and the circumferential direction of the rolling bearing 2. It has a pair of side wall regions 26 facing in the direction, and the sensor 40 is fixed to each of the pair of side wall regions 26 by welding with a radial gap between the bottom surface 25 and the rolling bearing 2.

<Action and effect of rolling bearing device>
In the rolling bearing device 1 according to the present embodiment, the detection unit 3 is completely housed in the groove portion 24 and does not project radially outward from the outer peripheral surface 21b. With such a configuration, the rolling bearing device 1 can prevent the detection unit 3 and the housing 7 from interfering with each other, and can secure the same degree of assembling property as the rolling bearing in which the detection unit 3 is not provided.

Further, the sensor 40 according to the present embodiment is fixed to the side wall region 26 of the groove portion 24 by welding. With such a configuration, the position where the sensor 40 is welded can be located closer to the outer peripheral surface 21b than the bottom surface 25. Here, a part of the side wall region 26 is melted by heating at the time of welding. Therefore, the region R1 including the melted portion and its surroundings in the side wall region 26 is heated to the quenching temperature or higher. As a result, the strength of the region R1 may be lower than that before welding.

However, in the present embodiment, the side wall region 26 is located closer to the outer peripheral surface 21b of the outer ring 21 than the bottom surface 25. Therefore, the radial distance D1 from the position where the region R1 is formed to the outer ring track 21a1 is longer than the radial distance from the bottom surface 25 to the outer ring track 21a1. That is, according to the rolling bearing device 1 according to the present embodiment, the distance between the region R1 where the strength can be weakened by welding and the outer ring track 21a1 can be made longer than when the sensor 40 is fixed to the bottom surface 25 by welding. can. As a result, it is possible to prevent the durability of the rolling bearing 2 from being lowered due to welding of the sensor 40.

As described above, according to the rolling bearing device 1 according to the present embodiment, it is possible to secure the same level of assembling property and durability as the rolling bearing not provided with the detection unit 3, and the assembling property and durability can be ensured. It is possible to meet both demands.

Further, the sensor 40 according to the present embodiment has a strain gauge 42 for detecting strain and an intermediate member 41 for transmitting the strain of the rolling bearing 2 to the strain gauge 42, and the intermediate member 41 has a pair of side wall regions. Each of them is fixed to 26 by welding, and the strain gauge 42 is fixed to the bottom surface 25 side of the intermediate member 41.

With this configuration, even if it is difficult to directly join the strain gauge 42 to the side wall region 26, the intermediate member 41 that can be easily joined to both the strain gauge 42 and the side wall region 26 is provided. By using it as a buffer, the strain gauge 42 can be indirectly joined to the side wall region 26. Further, by arranging the intermediate member 41 welded to the side wall region 26 on the outer peripheral surface 21b side as much as possible and fixing the strain gauge 42 on the bottom surface 25 side thereof, the distance D1 between the region R1 and the outer ring track 21a1 is made longer. Can be secured. As a result, it is possible to further suppress a decrease in the durability of the rolling bearing device 1.

Here, when a load is applied to the rolling bearing 2 from the rotating shaft, the inner ring 22 and the outer ring 21 partially extend (that is, distort) in at least one of the axial direction and the circumferential direction. Here, the "load" includes at least one of a load acting in the radial direction (radial load) and a load acting in the axial direction (thrust load or axial load).

The pair of side wall regions 26 according to the present embodiment face each other in the axial direction. Further, the pair of weld beads 51 fixing the intermediate member 41 and the pair of side wall regions 26 are positioned in parallel with each other with a gap in the axial direction. Therefore, when the outer ring 21 is distorted in the axial direction, the pair of side wall regions 26 are separated (or approached) in the axial direction, so that the intermediate member 41 is also elastically deformed more greatly. As a result, the strain gauge 42 can preferentially detect the strain in the axial direction. Further, by aligning the strain detection direction of the strain gauge 42 in the axial direction, the strain gauge 42 can detect the strain with higher sensitivity.

When the pair of side wall regions 26 are opposed to each other in the circumferential direction and the pair of weld beads 51 are also positioned in parallel with each other in the circumferential direction, the strain gauge 42 may preferentially detect the strain in the circumferential direction. can. In this way, it is possible to select a direction in which strain can be preferentially detected depending on the direction in which the pair of side wall regions 26 face each other and the direction in which the weld bead 51 is formed.

Further, the sensor 40 according to the present embodiment has a fixing portion 43 for fixing the strain gauge 42 to the bottom surface 25 side of the intermediate member 41, and the fixing portion 43 includes the central portion 42a of the strain gauge 42 and the intermediate member 41. At least two positions of the strain gauge 42 sandwiching the central portion 42a are fixed to the bottom surface 25 side of the intermediate member 41 in a non-fixed state between the bottom surface 25 side and the bottom surface 25 side.

When the central portion 42a of the strain gauge 42 faces the portion of the intermediate member 41 where the strain is more strongly generated (for example, the portion of the intermediate member 41 through which the virtual straight line VL1 passes), the strain can be detected more sensitively. .. The fixing portion 43 fixes the strain gauge 42 and the intermediate member 41 so that the central portion 42a of the strain gauge 42 faces the intermediate member 41 at a position avoiding the portion. Therefore, the stress generated in the fixing portion 43 can be reduced as compared with the case where the strain gauge 42 and the intermediate member 41 are completely fixed. Thereby, the durability of the fixing portion 43 can be further increased.

Further, since the fixing portion 43 fixes at least two positions of the strain gauge 42 sandwiching the central portion 42a, when the intermediate member 41 is distorted, the central portion 42a of the strain gauge 42 sets the central portion 42a. It is pulled by the fixing portion 43 located sandwiched between them. As a result, the strain gauge 42 can follow and deform the intermediate member 41 more accurately, and the strain gauge 42 can detect the strain with high sensitivity.

Further, the detection unit 3 according to the present embodiment further includes a wiring 61 that takes out the detection signal of the sensor 40 to the outside of the rolling bearing 2. The wiring 61 is fixed to the bottom surface 25 side of the sensor 40. With this configuration, the wiring 61 can be accommodated in the gap between the sensor 40 and the bottom surface 25, so that the position where the sensor 40 is welded is further away from the outer ring track 21a1 and more elements are contained in the groove portion 24. Can be accommodated.

Here, in the rolling bearing 2, the strain caused by the load from the rotating shaft extends toward both ends in the axial direction around the virtual straight line VL1 or contracts in the direction toward the virtual straight line VL1 from both ends in the axial direction. Tends to occur in. That is, the distortion of the portion of the outer ring 21 including the virtual intersection P3 tends to be larger than the distortion of the other portion of the outer ring 21.

Since the pair of side wall regions 26 according to the present embodiment are located so as to sandwich the virtual intersection P3 where the bottom surface 25 and the virtual straight line VL1 intersect in the axial direction (predetermined direction), the sensor 40 fixed to the side wall region 26 is used. It can be expanded or contracted more greatly. As a result, the sensor 40 can generate a larger distortion, and the sensor 40 can detect the distortion more sensitively.

Further, the side wall region 26 according to the present embodiment includes a stepped surface 262 facing in a direction including the radial outer direction, and the sensor 40 is fixed to the stepped surface 262 by welding. With this configuration, the sensor 40 can be stationary on the step surface 262. This makes it easier to aim, for example, when irradiating a laser for welding from the outside in the radial direction, so that the sensor 40 can be more easily fixed to the side wall region 26. Further, by allowing the sensor 40 to stand still on the step surface 262, the mounting position of the sensor 40 in the radial direction can be determined, and the sensor 40 can be mounted more reliably on the outer peripheral surface 21b side than the bottom surface 25. Further, by providing the stepped surface 262, the area where the sensor 40 and the side wall region 26 face each other can be increased, and the weld bead 51 can be increased. As a result, the sensor 40 can be more firmly attached to the side wall region 26.

<Modification example>
The rolling bearing device 1 according to the embodiment of the present invention has been described above. However, the implementation of the present invention is not limited to this, and various modifications can be made. Hereinafter, a modified example according to the embodiment of the present invention will be described. In the following description, the same reference numerals will be given to the parts that are not changed from the embodiments, and the description thereof will be omitted.

<First modification>
The sensor 40 according to the embodiment has an intermediate member 41 that transmits strain from the rolling bearing 2 to the strain gauge 42. However, the sensor 40 does not have to have the intermediate member 41. In this case, the strain gauge may be directly fixed to the side wall region 26 by welding as it is.

FIG. 4 is a cross-sectional view showing the detection unit 3a according to the first modification. FIG. 4 shows a cross section in the same XZ plane as in FIG. 2 (a). The detection unit 3a has a sensor 40a and a wiring 62. The sensor 40a includes a strain gauge. Both ends of the sensor 40a in the axial direction are fixed to the stepped surface 262 by forming a weld bead 51 by welding.

The wiring 62 includes a flat cable 63 and a wiring fixing portion 64 for fixing the flat cable 63 to the surface of the sensor 40a on the bottom surface 25 side. The wiring fixing portion 64 connects the flat cable 63 to the sensor 40a in a non-fixed state between the position P4 of the sensor 40a that intersects the virtual straight line VL1 and the position P5 of the flat cable 63 that intersects the virtual straight line VL1. It is fixed. The wiring fixing portion 64 is made of a metal material (for example, gold) and is formed by, for example, diffusion bonding.

The sensor 40a tends to be more distorted at position P4 on the virtual straight line VL1. Since the wiring fixing portion 64 according to this modification fixes the flat cable 63 at a position avoiding the position P4, the wiring fixing portion 64 is compared with the case where the flat cable 63 is entirely fixed to the sensor 40a. The stress generated in the wiring can be reduced, and the durability of the wiring fixing portion 64 can be further increased.

Since the sensor 40a according to the present embodiment does not have the intermediate member 41, the thickness in the radial direction can be mainly reduced as compared with the sensor 40 according to the above embodiment. Thereby, the depth of the groove portion 24 required for accommodating the sensor 40 can be made shallow. As a result, it is possible to suppress a decrease in the thickness of the outer ring 21 due to the formation of the groove portion 24, and it is possible to suppress a decrease in the strength of the rolling bearing 2.

<Second modification>
The side wall region 26 according to the embodiment has a step surface 262, and the sensor 40 is fixed to the step surface 262. However, the side wall region 26 does not have to have a step surface 262. In this case, the sensor 40 is fixed to the side surface 27 described later.

FIG. 5 is a cross-sectional view showing the detection unit 3b according to the second modification. FIG. 5 shows a cross section in the same XZ plane as in FIG. 2 (a). Each of the pair of side wall regions 26 according to this modification has a side surface 27. The pair of side surfaces 27 face each other in the axial direction and face each other. The side surface 27 is connected to the bottom surface 25 in the radial direction and is connected to the outer peripheral surface 21b in the radial direction.

The detection unit 3b has a sensor 40 and a wiring 61. The sensor 40 has an intermediate member 41, a strain gauge 42, and a fixing portion 43, each of which has the same configuration as that of the above embodiment. The intermediate member 41 is fixed to the pair of side surfaces 27 by welding. When fixing the intermediate member 41 to the side surface 27, the end faces 411 located on both ends in the axial direction of the intermediate member 41 face each other in the axial direction with the pair of side surfaces 27 in the radial direction. Irradiate the laser from the outside. As a result, the intermediate member 41 and the side surface 27 are melted to form the weld bead 52, and the intermediate member 41 is fixed to the pair of side surfaces 27.

In addition to the intermediate member 41 and the side surface 27, the weld bead 52 may contain a metal material that is a base material of the weld bead 52. For example, in a state where the metal material to be the base material of the welding bead 52 is positioned between the end face 411 and the side surface 27, laser irradiation is performed to melt the intermediate member 41, the side surface 27 and the base material, and the welding bead. 52 may be formed.

By fixing the sensor 40 to the side surface 27 by welding, the region R2 of the side wall region 26, which is heated to the quenching temperature or higher by welding, can be further separated from the outer ring track 21a1. In particular, the region R2 is formed on the lateral side of the side surface 27 in the axial direction. The radial thickness on both outer sides of the outer ring 21 tends to be thicker than the radial thickness on the inner side in the axial direction (for example, the position where the virtual straight line VL1 passes) because the outer ring track 21a1 is not formed. In this modification, by locating the region R2 on the outer side in the axial direction, which is thicker in the radial direction, it is possible to more reliably suppress the deterioration of the durability of the outer ring 21.

<Third modification example>
FIG. 6 is a cross-sectional view showing the detection unit 3c according to the third modification. FIG. 6 shows a cross section in the same XZ plane as in FIG. 2 (a). The detection unit 3c has a sensor 40 and a wiring 61. The detection unit 3c according to the present modification is different from the detection unit 3 according to the above embodiment in the position where the weld bead is formed, and is common in other points.

The weld bead 51 according to the embodiment is formed so as to be sandwiched in the radial direction between the step surface 262 and the intermediate member 41. However, the position where the weld bead is formed is not limited to this. The weld bead 53 according to the third modification is formed by melting a region including end faces 411 located on both ends in the axial direction of the intermediate member 41 and a step surface 262. As in the above embodiment, the weld bead 53 may contain a metal material as a base material in addition to the metal constituting the intermediate member 41 and the stepped surface 262.

In this modification, the intermediate member 41 is in direct contact with the step surface 262 in the radial direction. Therefore, in the detection unit 3c according to the present modification, the thickness in the radial direction of the weld bead 51 minutes of the above embodiment can be reduced, and the detection unit 3c can be made more compact. As a result, the depth of the groove portion 24 required for accommodating the detection portion 3c can be made shallow, and the deterioration of the durability of the rolling bearing 2 can be further suppressed.

Further, in this modification, the region R3 of the side wall region 26, which is heated to a temperature equal to or higher than the quenching temperature of the metal constituting the side wall region 26 by welding, is formed on the outer side in the axial direction of the intermediate member 41. It can be further away from 21a1. As a result, it is possible to more reliably suppress the decrease in durability of the outer ring 21.

<Fourth modification>
7 to 9 are explanatory views of the detection unit 3d according to the fourth modification. FIG. 7 is a cross-sectional view of the detection unit 3d in the same XZ plane as in FIG. 2A. FIG. 8 is a plan view of the detection unit 3d in the same XY plane as in FIG. FIG. 9 is a cross-sectional view of the detection unit 3d in the YZ plane cut by the cutting line indicated by the arrow IX of FIG.

See FIG. 7. The detection unit 3d has a sensor 40b and a wiring 65. The sensor 40b has an intermediate member 41, a strain gauge 420, and a fixing portion 43. The detection unit 3d according to this modification is different from the detection unit 3 according to the above embodiment in the arrangement of the strain gauge 420 and the wiring 65, and is common in other points. Further, in this modification, the groove portion 24 is provided only at the position where the detection portion 3d is attached and around the outer peripheral surface 21b as shown in FIG. The groove portion 24 may be provided over the entire circumference of the outer peripheral surface 21b as in the above embodiment.

See FIG. A part of the strain gauge 420 faces the intermediate member 41 in the radial direction as in the above embodiment (hereinafter, the region is referred to as a “first region”). On the other hand, the other partial region of the strain gauge 420 does not face the intermediate member 41 in the radial direction (hereinafter, the region is referred to as a "second region"). The second region is a region that protrudes from the intermediate member 41 in the circumferential direction (direction intersecting the predetermined direction).

The strain gauge 420 has a detection region 420a for detecting strain and a terminal region 420b for extracting a detection signal detected in the detection region 420a to the outside. The detection region 420a is provided in the first region of the strain gauge 420. The terminal region 420b is provided in the second region of the strain gauge 420.

The fixing portion 43 has at least two locations (four locations in this modification) of the strain gauge 420 located across the detection region 420a in a state where the detection region 420a and the intermediate member 41 are not fixed, and the intermediate member 41 is provided. It is fixed to the bottom surface 25 side of.

The wiring 65 is a wiring for taking out the detection signal of the strain gauge 420 to the outside, and is, for example, a flat cable. One end 65a of the wiring 65 is fixed to the outer peripheral surface 21b side (that is, the side opposite to the bottom surface 25) of the terminal region 420b in the strain gauge 420. Since the terminal region 420b does not face the intermediate member 41 in the radial direction, the intermediate member 41 and the wiring 65 interfere with each other even when one end 65a of the wiring 65 is fixed to the outer peripheral surface 21b side of the terminal region 420b. do not do. When the radial thickness of the wiring 65 is thinner than the radial gap between the intermediate member 41 and the strain gauge 420, one end 65a of the wiring 65 is fixed to the outer peripheral surface 21b side of the first region of the strain gauge 420. It may have been done.

As described above, the sensor 40b according to the present modification has a strain gauge 420 for detecting strain and an intermediate member 41 for transmitting the strain of the rolling bearing to the strain gauge 420, and the intermediate member 41 has a bottom surface 25. The strain gauge 420 is fixed to the bottom surface 25 side of the intermediate member 41 by welding to each of the pair of side wall regions 26 with a gap in the radial direction of the rolling bearing. With this configuration, the position where the intermediate member 41 is welded can be set closer to the outer peripheral surface 21b than the bottom surface 25.

Further, in this modification, a wiring 65 for taking out the detection signal of the sensor 40b to the outside of the rolling bearing is further provided, and the wiring 65 is fixed to the outer peripheral surface 21b (peripheral surface) side of the strain gauge 420. With this configuration, the thickness of the sensor 40b and the wiring 65 in the radial direction can be further reduced. As a result, the depth of the groove portion 24 required for accommodating the detection portion 3d can be made shallow, and the deterioration of the durability of the outer ring 21 can be more reliably suppressed.

Further, since the wiring 65 according to this modification is fixed to the region of the strain gauge 420 that does not face the intermediate member 41 in the radial direction, the wiring 65 and the wiring 65 are made thinner in the radial direction of the detection unit 3d. Interference with the intermediate member 41 can be prevented. As a result, the detection unit 3d can be made more compact.

<Others>
As shown in FIG. 1, in the present embodiment, the rolling bearing device 1 includes only one detection unit 3, but the present invention is not limited to this, and even if a plurality of detection units 3 are provided. good.

In the above-described embodiment and modification, the case where the rolling bearing 2 is a ball bearing of radial contact has been described. However, the rolling bearing 2 may be an axial contact ball bearing, an angular contact radial ball bearing, or an angular contact thrust ball bearing. In any rolling bearing, the virtual intersection P3 is determined by the same method as in the above embodiment (radial contact ball bearing).

The embodiments disclosed as described above are exemplary in all respects and are not restrictive. That is, the rolling bearing device of the present invention is not limited to the illustrated form, and may be another form within the scope of the present invention.

1: Bearing device, 2: Bearing, 21: Outer ring, 21a: Inner peripheral surface, 21a1: Outer ring track,
21b: outer peripheral surface, 22: inner ring, 22a: inner peripheral surface, 22b: outer peripheral surface,
22b1: Inner ring track, 23: Rolling element, 24: Groove, 25: Bottom,
26: Side wall area, 261: 1st side surface, 262: Step surface, 263: 2nd side surface,
27: Side surface, 3: Detection unit, 3a: Detection unit, 3b: Detection unit, 3c: Detection unit,
3d: detector, 40: sensor, 40a: sensor, 40b: sensor,
41: Intermediate member, 411: End face, 42: Strain gauge, 42a: Central part,
420: Strain gauge, 420a: Detection area, 420b: Terminal area,
43: Fixed part, 51: Welded bead, 52: Welded bead, 53: Welded bead,
61: Wiring, 61a: One end, 61b: The other end, 62: Wiring,
63: Flat cable, 64: Wiring fixing part, 65: Wiring, 65a: One end,
7: Housing, 9: Bearing, 91: Outer ring, 91a: Inner peripheral surface,
91a1: Outer ring track, 91b: Outer peripheral surface, 91c: Groove, 92: Inner ring,
93: Rolling element, 94: Sensor, 92b: Outer peripheral surface, 92b1: Inner ring track,
95: Intermediate member, 96: Strain gauge, 97: Wiring, 98: Housing,
C1: Center line, P1: 1st point, P2: 2nd point, VL1: Virtual straight line,
P3: Virtual intersection, W1: Width, W2: Width, P4: Position, P5: Position,
R1: region, R2: region, R3: region, R9: region, D1: distance,
D9: Distance

Claims (8)

A rolling bearing having an outer ring having an outer ring track on the inner peripheral surface, an inner ring having an inner ring track on the outer peripheral surface, and a plurality of rolling elements interposed between the outer ring track and the inner ring track.
A sensor that detects the state of the rolling bearing and
Equipped with
A groove for accommodating the sensor so as not to protrude from the peripheral surface is formed on at least one peripheral surface of the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring.
The groove has a bottom surface and a pair of side wall regions facing in a predetermined direction including at least one of the axial direction and the circumferential direction of the rolling bearing.
The sensor is fixed to the pair of side wall regions by welding with a gap between the bottom surface and the rolling bearing in the radial direction.
Rolling bearing device. The sensor has a strain gauge for detecting strain and an intermediate member for transmitting the strain of the rolling bearing to the strain gauge.
The intermediate member is fixed to the pair of side wall regions by welding, respectively.
The strain gauge is fixed to the bottom surface side of the intermediate member.
The rolling bearing device according to claim 1. The sensor has a fixing portion for fixing the strain gauge to the bottom surface side of the intermediate member.
The fixed portion is in a state where the central portion of the strain gauge and the bottom surface side of the intermediate member are not fixed, and at least two locations of the strain gauge located across the central portion are located in the middle. Fixed to the bottom side of the member,
The rolling bearing device according to claim 2. Further provided with wiring for taking out the detection signal of the sensor to the outside of the rolling bearing.
The wiring is fixed to the bottom surface side of the sensor.
The rolling bearing device according to any one of claims 1 to 3. Further provided with wiring for taking out the detection signal of the sensor to the outside of the rolling bearing.
The wiring is fixed to the peripheral surface side of the strain gauge so as not to protrude from the peripheral surface.
The rolling bearing device according to claim 2 or 3. The bottom surface intersects a virtual straight line passing through a first point where the rolling element contacts the outer ring track and a second point where the rolling element contacts the inner ring track.
The pair of side wall regions are located so as to sandwich a virtual intersection where the bottom surface and the virtual straight line intersect in the predetermined direction.
The rolling bearing device according to any one of claims 1 to 5. The side wall region includes a stepped surface facing in a direction including the radial outer side.
The sensor is fixed to the step surface by welding.
The rolling bearing device according to any one of claims 1 to 6. The side wall region includes the side surface facing in the predetermined direction.
The sensor is fixed to the side surface by welding.
The rolling bearing device according to any one of claims 1 to 6.

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