Damage detection system for hub unit bearing

Abstract

To provide a damage detection system for a hub unit bearing which is capable of detecting the generation of damage on a raceway surface and identifying the damaged raceway surface, without influence from variations in vehicle speed.SOLUTION: In a damage detection system for a hub unit bearing 10, rotation speed sensors 52A, 52B, and 52C are horizontally supported and fixed to an outer ring 20 or to a part that does not rotate together with the outer ring 20. A calculation unit detects damage generated on at least one surface of outer ring raceways 20a, 20b or inner ring raceways 31a, 31b by capturing phase advances or delays in signals from rotation speed sensors 52A, 52B, and 52C, occurring at a period calculated based on at least the pitch and orbital speed of rolling elements 40.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a damage detection system for a hub unit bearing.

Background Art

[0002] The outer ring and hub ring of the hub unit bearing are manufactured by hot forging medium carbon steel with a carbon content of 0.5 to 0.6% by mass and then heat-treating the raceway surface. The inner ring raceway surface portion of the hub ring is relatively thick, but the outer ring raceway surface portion is thin, so damage to the raceway surface such as flaking often occurs on the outer ring raceway surface. Since medium carbon steel has higher toughness than bearing steel (C: 1% by mass), cracks at the dynamic maximum shear stress position are difficult to extend toward the surface and proceed parallel to the raceway surface. In such a case of flaking, initially the surface does not peel off, and only the portion from the crack to the raceway surface is indented by the rolling elements, so there is little deterioration in vibration and sound. However, when the crack reaches the surface of the raceway as the crack progresses, the surface of the raceway peels off all at once and the flaking progresses. The failure mode in which flaking progresses suddenly from a certain point is an unfavorable failure mode in the case of a vehicle such as a large truck where the distance from the driver to the wheel bearing is long and it is difficult for the driver to detect small damage. Also, considering future driverless vehicles and platoon driving, it is desirable to detect damage at an early stage when the damage to the hub unit bearing is small.

[0003] As shown in FIG. 7, the hub unit bearing 100 of Patent Document 1 includes an outer ring 101 having a double row of outer ring raceways 101a, a hub 102 having a double row of inner ring raceways 102a, and a plurality of rolling elements 103 rotatably provided between the outer ring raceway 101a and the inner ring raceway 102a. The hub unit bearing 100 is provided with encoders 104 on both axial sides of the hub 102, and can detect the torque applied to the hub 102 based on the phase difference between the detection signals of sensors (not shown) facing each encoder 104.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2004-19934 Summary of the Invention Problems to be Solved by the Invention

[0005] Damage to the outer ring and hub of the hub unit bearing, particularly to the outer ring raceway surface, is a cause of deterioration in vibration and acoustics, and early detection is desirable.

[0006] However, the hub unit bearing 100 described in Patent Document 1 can detect the torque applied to the hub 102 based on the phase difference between the detection signals of two sensors, but it cannot detect damage occurring on the raceway surfaces 101a and 102a of the outer ring 101 and the hub 102.

[0007] The present invention has been made in view of the above-described problems, and an object thereof is to provide a damage detection system for a hub unit bearing that can identify the occurrence of damage to the raceway surface and the damaged raceway surface without being affected by changes in the vehicle speed. Means for Solving the Problems

[0008] Therefore, the above object of the present invention is achieved by the configuration of the following [1] related to the hub unit bearing. [1] An outer ring having a double row of outer ring raceways on its inner peripheral surface and not rotating while being supported and fixed to a suspension device during use, A mounting flange provided at the outer end portion of the outer peripheral surface, a hub having a double row of inner ring raceways at the intermediate portion and the inner end portion, and rotating together with a wheel during use, A plurality of rolling elements are respectively provided between each of the outer ring raceways and each of the inner ring raceways so as to be freely rotatable, and the outer ring raceway and the inner ring raceway of the outer row constitute the outer row bearing portion, and the outer ring raceway and the inner ring raceway of the inner row constitute the inner row bearing portion respectively, An encoder fixed near at least one of the outer row bearing portion and the inner row bearing portion, A rotational speed sensor that is disposed opposite to the encoder and detects the rotational speed of the hub, An arithmetic unit that processes the signal of the rotational speed sensor, A hub unit bearing damage detection system that includes the above and detects damage occurring on at least one surface of the outer ring raceway and the inner ring raceway, The rotational speed sensor is horizontally supported and fixed to a portion that does not rotate with the outer ring or together with the outer ring, The arithmetic unit detects the occurrence of the damage by capturing the advance or delay of the signal phase of the rotational speed sensor that occurs at a period calculated based on at least the pitch and the revolution speed of the rolling elements, A hub unit bearing damage detection system.

Advantages of the Invention

[0009] According to the hub unit bearing damage detection system of the present invention, it is possible to detect the occurrence of damage on the raceway surfaces of the outer ring and the inner ring and identify the damaged raceway surface without being affected by the speed change of the vehicle.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6A

Figure 6B

Figure 7

Mode for Carrying Out the Invention

[0011] Hereinafter, each embodiment and modification of the damage detection system for a hub unit bearing according to the present invention will be described in detail with reference to the drawings.

[0012] [First Embodiment] A damage detection system for a hub unit bearing according to a first embodiment of the present invention will be described in detail with reference to FIG. 1. Regarding the hub unit bearing, throughout this specification and the claims, "axially inner side" refers to the vehicle body side of the hub unit bearing when attached to the vehicle body, which is the right side in FIG. 1, and "axially outer side" refers to the wheel side of the hub unit bearing when attached to the vehicle body, which is the left side in FIG. 1. Therefore, for the bearing portion, outer raceway, and inner raceway arranged on the inner side, they are also referred to as the bearing portion of the inner row, the outer raceway of the inner row, and the inner raceway of the inner row, and for the bearing portion, outer raceway, and inner raceway arranged on the outer side, they are also referred to as the bearing portion of the outer row, the outer raceway of the outer row, and the inner raceway of the outer row.

[0013] As shown in FIG. 1, the hub unit bearing 10 of the present embodiment is a hub unit bearing for a driven wheel, and mainly includes an outer ring 20 as a fixed-side member, a hub 30 as a rotating-side member, a plurality of rolling elements 40, and a pair of detection devices 50A and 50B. Further, the damage detection system for the hub unit bearing 10 includes this hub unit bearing 10 and an arithmetic unit (not shown) that processes signals from rotation speed sensors 52A and 52B of the detection devices 50A and 50B of the hub unit bearing 10, which will be described later.

[0014] The outer ring 20 is provided with a stationary-side flange 21 on its outer peripheral surface, and has an outer ring raceway 20a for the outer row and an outer ring raceway 20b for the inner row on its inner peripheral surface respectively. During use, the outer ring 20 is coupled and fixed to the knuckle of the suspension device by connecting the stationary-side flange 21, and rotates without being supported by this suspension device.

[0015] The hub 30 is composed of a hub shaft 31 and an inner ring 32 that is fitted and caulked to the hub shaft 31, and is arranged coaxially (concentrically) with the outer ring 20 on the radially inner side of the outer ring 20.

[0016] On the hub shaft 31, at a portion protruding axially outward from the axially outer opening of the outer ring 20, a ring-shaped mounting flange 33 is provided that extends radially outward to support and fix a braking rotating member such as a wheel (driven wheel) and a disc rotor (none of which are shown).

[0017] The mounting flange 33 is provided with a plurality of insertion holes 33a, and hub bolts 34 are serration-fitted into the respective insertion holes 33a. Note that by using the plurality of insertion holes 33a of the mounting flange 33 as female screw holes and screwing in the hub bolts, it is also possible to support and fix a braking rotating member such as a wheel and a disc rotor.

[0018] On the outer peripheral surface of the hub shaft 31, at a portion facing the outer ring raceway 20a of the outer row, an inner ring raceway 31a of the outer row is provided. Also, on the axially inner end portion of the outer peripheral surface of the hub shaft 31 that faces the outer ring raceway 20b of the inner row, a small-diameter stepped portion 31c is provided. The hub shaft 31 partially constitutes the outer peripheral surface of the small-diameter stepped portion 31c, and has a caulking portion 35 in which the axially inner end portion is deformed radially outward to caulk and fix the inner ring 32.

[0019] On the outer peripheral surface of the inner ring 32, at a portion facing the outer ring raceway 20b of the inner row, an inner ring raceway 31b of the inner row is provided. The inner ring 32 is externally fitted onto the small-diameter stepped portion 31c of the hub shaft 31 with its axially outer end face abutting against the stepped surface of the small-diameter stepped portion 31c, and is clamped and fixed to the hub shaft 31 by a clamping portion 35 in which the axially inner end of the small-diameter stepped portion 31c is deformed radially outward.

[0020] The rolling elements 40 are provided between the outer ring raceway 20a of the outer row and the inner ring raceway 31a of the outer row, and between the outer ring raceway 20b of the inner row and the inner ring raceway 31b of the inner row, and are rotatably held by the respective cages 41.

[0021] Note that the outer row bearing portion 36A is formed by the outer ring raceway 20a of the outer row, the inner ring raceway 31a of the outer row, and the rolling elements 40, and the inner row bearing portion 36B is formed by the outer ring raceway 20b of the inner row, the inner ring raceway 31b of the inner row, and the rolling elements 40.

[0022] A seal ring 42 is supported and fixed to the axially outer end of the inner peripheral surface of the outer ring 20. The seal ring 42 closes the axially outer end opening of the internal space 44 in which a plurality of rolling elements 40 are provided, which exists between the inner peripheral surface of the outer ring 20 and the outer peripheral surface of the hub shaft 31. The seal ring 42 is in sliding contact with the large-diameter stepped portion on the axially outer side of the inner ring raceway 31a of the outer row on the outer peripheral surface of the hub shaft 31.

[0023] The detection device 50A is a radial sensor disposed near the outer row bearing portion 36A, that is, at the axially intermediate portion of the hub unit bearing 10, for detecting the rotational speed of the hub 30, and includes a magnetic encoder 51A and a rotational speed sensor 52A.

[0024] The magnetic encoder 51A is composed of a support ring 53A externally fitted and fixed to the shoulder of the inner ring raceway 31a of the hub shaft 31, and an encoder body 54A supported and fixed to the support ring 53A. The support ring 53A is formed in an annular shape by performing press working on a magnetic metal plate such as a ferrite stainless steel plate like SUS430 or a rolled steel plate like SPCC.

[0025] The encoder body 54A is formed into an annular shape as a whole by a permanent magnet obtained by mixing a magnetic material such as ferrite powder into rubber or a thermoplastic resin, and is attached and fixed to the outer peripheral surface of the support ring 53A. On the outer peripheral surface of the encoder body 54A, S poles and N poles are magnetized alternately and at equal pitches in the circumferential direction to form the surface to be inspected 56a.

[0026] The rotational speed sensor 52A is for detecting the rotational speed of the hub 30, particularly the rotational speed of the outer portion of the hub 30. The rotational speed sensor 52A is arranged with the detection surface 55a facing the surface to be inspected 56a of the magnetic encoder 51A, and is inserted into the radial hole 20d of the outer ring 20 which is a fixed-side member and fixed horizontally.

[0027] The detection device 50B is an axial sensor arranged near the inner row of bearing portions 36B, that is, at the axially inner end portion of the hub unit bearing 10, for detecting the rotational speed of the hub 30, and includes a magnetic encoder 51B and a rotational speed sensor 52B.

[0028] The magnetic encoder 51B is composed of a support ring 53B and an encoder body 54B. The support ring 53B is formed into an annular shape as a whole with an L-shaped cross section by performing press working on a magnetic metal plate such as a ferrite-based stainless steel plate like SUS430 or a rolled steel plate like SPCC. The axially outer portion of the support ring 53B is externally fitted and fixed to the inner ring 32.

[0029] The encoder body 54B is formed into an annular shape as a whole by a permanent magnet obtained by mixing a magnetic material such as ferrite powder into rubber or a thermoplastic resin, and is attached and fixed to the inner surface of the annular portion of the support ring 53B bent radially inward. On the inner side surface of the encoder body 54B, S poles and N poles are magnetized alternately and at equal pitches in the circumferential direction to form the surface to be inspected 56b.

[0030] The rotational speed sensor 52B is for detecting the rotational speed of the hub 30, particularly the rotational speed of the inner part of the hub 30. The rotational speed sensor 52B has its detection surface 55b facing the surface to be detected 56b of the magnetic encoder 51B and is horizontally fixed to the side cover 60 that closes the inner opening of the outer ring 20.

[0031] In the damage detection system of the hub unit bearing 10 of the present embodiment configured as described above, the arithmetic unit can determine the presence or absence of damage to the outer ring raceway or the inner ring raceway and identify the location where the damage has occurred based on the phase difference of the rotational speed signals detected by the detection devices 50A and 50B without being affected by changes in the rotational speed.

[0032] Specifically, as shown in FIG. 2(a), in the hub unit bearing 10 where no damage has occurred in the raceways of either of the two bearing parts 36A and 36B, the central axis CL of the hub 30 does not move up and down. However, as shown in FIG. 2(b), for example, when damage has occurred in the bearing part 36A of the outer row, the central axis CL of the hub 30 vibrates up and down at the timing when the rolling element 40 enters and exits the concave part (damaged part) of the outer ring raceway 20a of the outer row. Generally, in both bearing parts 36A and 36B, the upper part is the load zone, and a radial load acts between the upper part of the outer ring raceway 20a and the inner ring raceway 31a, so damage is likely to occur in the upper part of the outer ring raceway 20a. In FIG. 2(b), the damaged bearing part 36A is shown by a dashed line.

[0033] FIGS. 3(a) and (b) are schematic cross-sectional views taken along the line A-A of FIG. 1. As shown in FIG. 3(a), from the state where the central axis CL of the hub 30 (encoder main body 54A) rotates clockwise without vibrating up and down (a state without damage), when the rolling element 40 falls into the concave parts (damaged parts) of the outer ring raceways 20a and 20b, as shown in FIG. 3(b), the hub 30 is displaced upward in the vertical direction with respect to the outer ring 20. Then, when passing through the concave part (damaged part), the hub 30 is displaced downward in the vertical direction with respect to the outer ring 20 and returns to the original state (the state of FIG. 3(a)).

[0034] When the hub 30 (encoder body 54A) is displaced upward in the vertical direction, the encoder body 54A is displaced in the direction opposite to the rotation direction, so a phase delay occurs in the output signal of the rotational speed sensor 52A. Also, when the hub 30 is displaced downward in the vertical direction (return), the encoder body 54A is displaced on the same side as the rotation direction, so a phase advance occurs in the output signal of the rotational speed sensor 52A.

[0035] This phenomenon of phase delay and advance also occurs similarly in the encoder body 54B and the rotational speed sensor 52B in the detection device 50B.

[0036] That is, phase delay and advance occur in the output signals from the rotational speed sensors 52A and 52B arranged near the damaged bearing parts 36A and 36B. Therefore, it can be understood that there is a high possibility that the bearing parts 36A and 36B near the rotational speed sensors 52A and 52B where phase delay and advance are detected are damaged in the arithmetic unit.

[0037] This delay and advance of the output signal occur regularly in pairs of phase delay and advance, so it is easy to grasp the generation of the signal. Note that for each encoder 51A and 51B, two rotational speed sensors 52A and 52B can be arranged at the 3 o'clock and 9 o'clock phases of the clock when viewed from the inner side in the axial direction of the hub 30 to improve the detection accuracy.

[0038] The timing at which delay and advance occur in the signal is generated at a period calculated from an equation using the pitch of the rolling elements 40 and the revolution speed of the rolling elements 40 as parameters when the outer raceways 20a and 20b are damaged. Also, when the inner raceways 31a and 31b are damaged, it is generated at a period calculated from an equation using the pitch of the rolling elements 40, the revolution speed of the rolling elements 40, and the rotation speed of the hub 30 as parameters. Note that a specific equation can be obtained by referring to, for example, "Other General 12.3 Rotation and Revolution Speeds of Rolling Elements" described on page 248 of NSK Technical Report CAT.No.728i 2020 C-4.

[0039] Therefore, at least one side of the signals from the rotational speed sensors 52A and 52B is averaged to obtain the rotational speed (vehicle speed) of the bearings, and if a delay or advance of the phase above the threshold value at the period calculated therefrom occurs in the signals before averaging in the bearing parts 36A and 36B, it is determined that the bearing parts 36A and 36B are damaged (extracted by a filter or the like). As a result, among the bearing parts 36A in the outer row and the bearing parts 36B in the inner row, the damaged bearing parts 36A and 36B can be discriminated without being affected by the change in the vehicle speed.

[0040] Furthermore, when the period of the phase delay or advance occurs at a period calculated from the pitch of the rolling elements 40 and the revolution speed of the rolling elements 40, it is discriminated as damage to the outer ring raceways 20a and 20b, and when it occurs at a period calculated from the pitch of the rolling elements 40, the revolution speed of the rolling elements 40, and the rotational speed of the hub 30, it can be discriminated as damage to the inner ring raceways 31a and 31b.

[0041] [First Modification of the First Embodiment] As shown in FIG. 4A, the hub unit bearing 10 of the first modification of the first embodiment does not have the detection device 50B provided in the hub unit bearing 10 of the first embodiment, and includes only the detection device 50A, and is disposed in the vicinity of the bearing part 36A in the outer row.

[0042] As can be seen from FIG. 2, the farther the measurement position is from the bearing part without damage (the bearing part 36B in the inner row in FIG. 2), the greater the phase delay or advance becomes. Therefore, if it is known in advance which bearing part is likely to be damaged (for example, the bearing part 36A in the outer row), by mounting the detection device in the vicinity of the bearing part that is likely to be damaged (for example, the bearing part 36A in the outer row), the detection device can be reduced and the cost can be reduced.

[0043] In this case, the signal of the rotational speed sensor 52A is averaged, and compared with the signal before averaging. If the deviation from the averaged signal is equal to or greater than the threshold value, it is determined as damage. In this modified example, since there is only one detection device 50A, it is difficult to identify the row of the damaged bearing unit. However, since the hub unit bearing 10 requires replacement of the whole even when one row of bearing units is damaged, there is no practical problem as long as the occurrence of damage can be detected even if the damaged bearing unit cannot be identified.

[0044] [Second Modified Example of the First Embodiment] As shown in FIG. 4B, the hub unit bearing 10 of the second modified example of the first embodiment does not have the detection device 50A included in the hub unit bearing 10 of the first embodiment, but only includes the detection device 50B, and is arranged near the bearing unit 36B of the inner row. This modified example is also preferably applied when it is known in advance which bearing unit (for example, the bearing unit 36B of the inner row) is likely to be damaged. Since the other configurations and operations are the same as those of the hub unit bearing 10 of the first modified example, detailed description thereof will be omitted.

[0045] [Second Embodiment] In the hub unit bearing 10 (see FIG. 1) of the first embodiment, since the detection device 50A is arranged at the shoulder of the inner ring raceway 31a of the outer row, when damage occurs in the bearing unit 36A of the outer row, the phase delay / advance on the side of the bearing unit 36A of the outer row is small (see FIG. 2), and it is difficult to detect with the detection device 50A.

[0046] Therefore, as shown in FIG. 5, in the hub unit bearing 10 of the present embodiment, instead of the detection device 50A of the hub unit bearing 10 of the first embodiment, a detection device 50C which is an axial sensor is provided between the mounting flange 33 and the outer ring 20. That is, the magnetic encoder 51C is provided on the inner side surface 33b of the mounting flange 33 and on the inner diameter side of the PCD of the insertion hole 33a of the hub bolt 34, and the rotational speed sensor 52C is arranged on the outer diameter portion 20c of the outer ring 20 which is a fixed side member with the detection surface 55c facing the detected surface 56c of the magnetic encoder 51C from the axial direction.

[0047] As a result, the axial distance between the bearing portion 36A of the outer row and the measurement position can be extended, increasing the amount of advance or delay of the signal phase when damage occurs to the bearing portion 36A of the outer row, and making it easier to detect damage to the bearing portion 36A of the outer row.

[0048] The hub unit bearing 10 of the present embodiment is suitable for application to a hub unit bearing 10 in which damage is likely to occur to the bearing portion 36A of the outer row due to vehicle specifications (for example, the axial position relationship between the tire center and the hub unit bearing, etc.).

[0049] [First Modification Example of the Second Embodiment] As shown in FIG. 6A, the hub unit bearing 10 of this modification does not have the detection device 50B provided in the hub unit bearing 10 of the second embodiment, and a detection device 50C is provided between the mounting flange 33 and the outer ring 20. The magnetic encoder 51C is provided on the inner side surface 33b of the mounting flange 33 and on the inner diameter side of the PCD of the insertion hole 33a, and the rotational speed sensor 52C is arranged on the outer diameter portion 20c of the outer ring 20, which is a fixed side member, with the detection surface 55c facing the detected surface 56c of the magnetic encoder 51C from the axial direction.

[0050] The hub unit bearing 10 of this modification detects damage to the bearing portion 36A of the outer row and the bearing portion 36B of the inner row with one magnetic encoder 51C. Although it is difficult to identify the row of the damaged bearing portion, cost reduction is possible.

[0051] Other configurations and operations are the same as those of the hub unit bearing 10 of the second embodiment, and it can be suitably used for a hub unit bearing 10 in which damage is likely to occur to the bearing portion 36A of the outer row.

[0052] [Second Modification Example of the Second Embodiment] As shown in FIG. 6B, in the hub unit bearing 10 of this modification, one detection device 50C has a magnetic encoder 51C provided on the outer diameter side of the inner side surface 33b of the mounting flange 33 and the PCD of the insertion hole 33a, and a rotational speed sensor 52C has a detection surface 55c facing the surface to be detected 56c of the magnetic encoder 51C from the axial direction and is arranged on a knuckle (not shown) which is a fixed side member.

[0053] Compared with the hub unit bearing 10 of the first modification of the second embodiment, the hub unit bearing 10 of this modification can further extend the axial distance between the bearing portion 36A of the outer row and the measurement position. Thereby, when damage occurs in the bearing portion 36A of the outer row, the amount of advance and delay of the signal phase increases, making it easier to detect damage to the bearing portion 36A of the outer row. Also, since there is one detection device 50C, it is difficult to specify the row of the damaged bearing portion, but cost reduction is possible.

[0054] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified, improved, etc. For example, in the above embodiment, the hub unit bearing for a driven wheel has been described, but it can also be applied to a hub unit bearing for a driving wheel, and the same effects can be obtained. Also, in this embodiment, balls are used as rolling elements, but tapered rollers may also be used. Furthermore, in the damage detection system of this embodiment, a third-generation hub unit bearing in which the hub is composed of a hub shaft (hub ring) and an inner ring has been described, but the present invention can also be applied to other-generation hub unit bearings such as a hub unit bearing in which the hub is composed of a pair of inner rings and a hub shaft.

[0055] As described above, the following matters are disclosed in this specification. (1) An outer ring having double-row outer ring raceways on the inner peripheral surface and not rotating in a state of being supported and fixed by a suspension device during use, a mounting flange provided at the outer end of the outer peripheral surface, a hub having double-row inner ring raceways at the intermediate portion and the inner end portion, and rotating together with a wheel during use, A plurality of rolling elements are respectively provided between each of the outer raceways and each of the inner raceways so as to be rotatable, and the outer raceway and the inner raceway of the outer row constitute the bearing portion of the outer row, and the outer raceway and the inner raceway of the inner row constitute the bearing portion of the inner row respectively, and an encoder fixed in the vicinity of at least one of the bearing portion of the outer row and the bearing portion of the inner row; a rotational speed sensor arranged opposite to the encoder for detecting the rotational speed of the hub; an arithmetic unit for processing the signal of the rotational speed sensor; A damage detection system for a hub unit bearing, comprising the above components, for detecting damage occurring on the surface of at least one of the outer raceway and the inner raceway, the rotational speed sensor is horizontally supported and fixed to a portion that does not rotate with the outer ring or together with the outer ring, the arithmetic unit detects the occurrence of the damage by capturing the advance or delay of the signal phase of the rotational speed sensor that occurs at a period calculated based on at least the pitch and the revolution speed of the rolling elements, A damage detection system for a hub unit bearing. According to this configuration, it is possible to identify the occurrence of damage on the raceway surfaces of the outer ring and the inner ring and the damaged raceway surface without being affected by the speed change of the vehicle.

[0056] (2) The encoder provided in the vicinity of the bearing portion of the outer row is an axial encoder provided on the inner side surface of the mounting flange, the rotational speed sensor is arranged axially opposite to the axial encoder, The damage detection system for a hub unit bearing according to (1). According to this configuration, the measurement position can be separated from the damaged bearing portion, and the presence or absence of damage to the bearing portion of the outer row can be effectively detected.

[0057] (3) The hub has a hub shaft and an inner ring that is fitted to the hub shaft and fastened and fixed, The encoder provided near the bearing portion of the inner row is an axial encoder attached to the large end face of the inner ring and provided on a support ring that bends radially inward. The rotational speed sensor is arranged axially opposite to the axial encoder. The damage detection system for the hub unit bearing according to (1). According to this configuration, the detection device can be configured compactly, and the hub unit bearing can be made smaller in diameter.

[0058] (4) The encoder is fixed near the bearing portion of the outer row and the bearing portion of the inner row. The rotational speed sensor is arranged opposite to each encoder. The hub unit bearing according to any one of (1) to (3). According to this configuration, the rotational speed can be detected near the bearing portions of the outer row and the inner row, and the detection accuracy is improved.

Explanation of Signs

[0059] 10 Hub unit bearing 20 Outer ring 20a Outer ring raceway of the outer row 20b Outer ring raceway of the inner row 30 Hub 31 Hub shaft 31a Inner ring raceway of the outer row 31b Inner ring raceway of the inner row 32 Inner ring 33 Mounting flange 33b Inner side surface 36A Bearing portion of the outer row 36B Bearing portion of the inner row 40 Rolling element 50A, 50B, 50C Detection device 51A, 51B, 51C Magnetic encoder (encoder) 52A, 52B, 52C Rotational speed sensor 53A, 53B, 53C Support ring 54A, 54B, 54C Encoder body 55a, 55b, 55c inspection surfaces 56a, 56b, 56c surfaces to be inspected

Claims

1. an outer ring having a double row outer ring raceway on its inner circumferential surface and being supported and fixed to a suspension device during use so as not to rotate; a hub having a mounting flange provided on an outer end of an outer peripheral surface and a double row inner ring raceway on an intermediate portion and an inner end portion, the hub rotating together with a wheel during use; a plurality of rolling elements are provided between each of the outer ring raceways and each of the inner ring raceways so as to be able to roll freely, the outer ring raceway and the inner ring raceway of an outer row forming an outer row bearing portion, and the outer ring raceway and the inner ring raceway of an inner row forming an inner row bearing portion; an encoder fixed near at least one of the outer row of bearings and the inner row of bearings; a rotation speed sensor disposed opposite the encoder for detecting a rotation speed of the hub; A calculation unit for processing a signal from the rotation speed sensor; A damage detection system for a hub unit bearing for detecting damage occurring on a surface of at least one of the outer ring raceway and the inner ring raceway, The rotation speed sensor is horizontally supported and fixed to the outer ring or a portion that does not rotate together with the outer ring, The calculation unit detects the occurrence of the damage by capturing an occurrence of an advance or delay in the signal phase of the rotation speed sensor, which occurs at a period calculated based on at least the pitch and revolution speed of the rolling element. Hub unit bearing damage detection system.

2. the encoder provided near the bearing portion of the outer row is an axial encoder provided on an inner side surface of the mounting flange, The rotation speed sensor is disposed to face the axial encoder in the axial direction. The hub unit bearing damage detection system according to claim 1 .

3. The hub has a hub axle and an inner ring that is fitted onto the hub axle and fixed by crimping, the encoder provided near the bearing portion of the inner row is an axial encoder provided on a support ring attached to a large end surface of the inner ring and bent radially inward, The rotation speed sensor is disposed to face the axial encoder in the axial direction. The hub unit bearing damage detection system according to claim 1 .

4. the encoder is fixed near the outer row of bearings and the inner row of bearings; The rotation speed sensors are disposed opposite to the encoders. The damage detection system for a hub unit bearing according to any one of claims 1 to 3.

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