Ball bearing

Abstract

To provide a tapered roller bearing that can detect occurrence of skew of a tapered roller and notify a user of it.SOLUTION: A tapered roller bearing 10 includes: an outer ring 11 including an outer ring raceway surface 11a at an inner peripheral surface; an inner ring 12 including an inner ring raceway surface 12a at an outer peripheral surface; a tapered roller 13 provided between the outer ring raceway surface 11a and the inner ring raceway surface 12a so as to be capable of rolling; and a sensor 20 for detecting extension of an axial distance of a space dynamically occupied by the tapered roller 13 due to skew of the tapered roller.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tapered roller bearing.

Background Art

[0002] A bearing is a device that rotatably supports the axles of vehicles and the rotating shafts of other machines, and there are various types of bearings. In particular, a tapered roller bearing that uses tapered rollers has a higher load capacity compared to a ball bearing that uses spherical balls, while having a lower cross-sectional height of the bearing portion. Therefore, for example, it is used as a bearing for vehicles that are heavy and have a high axle load.

[0003] Patent Document 1 discloses a wheel bearing device using tapered rollers. In this device, a pair of inner rings are axially fixed to a hub ring by a caulking portion formed by plastically deforming the end portion of the small-diameter step portion of the hub ring radially outward. The small end faces of the pair of inner rings are formed to be inclined by an inclination angle set to 10° or less with respect to a plane orthogonal to the axis, and the respective small end faces are abutted and set in a surface contact state. Thereby, the small end faces of the pair of inner rings are engaged via a predetermined inclination angle, and creep is prevented from occurring on the fitting surface between the small-diameter step portion and the inner ring as long as the pair of inner rings do not simultaneously creep.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a tapered roller bearing, when the preload is low, due to inevitable machining errors, a tilting behavior called skew may occur with respect to the advancing direction of the tapered roller. This skew is more likely to occur as the length of the tapered roller increases and as the preload decreases. Also, the skew is more likely to occur as the load position of the tapered roller deviates from the axial center of the tapered roller. Furthermore, the skew is more likely to occur as the wear and surface roughness of the large flange surface of the bearing progress.

[0006] When the skew increases, the tail part on the small diameter side of the tapered roller comes into contact with the small flange, the torque of the bearing increases, and there is a risk of seizure or damage to the small flange of the inner ring. In particular, tapered roller bearings for wheels are more likely to have skew originally due to factors such as the following (1) to (4). Therefore, with the use of the bearing, the wear and surface roughness of the large flange surface progress, and the likelihood of further skew occurring increases.

[0007] (1) Since it is necessary to obtain a load capacity, a relatively long roller with a length 1.5 times or more the diameter is used. (2) Because a moment load based on the road surface reaction force is applied, the load is usually biased towards the large diameter side of the tapered roller. (3) Due to low torque requirements and seizure prevention, too much preload cannot be applied. (4) Due to the sliding friction between the curved surface of the head of the tapered roller and the large flange, the tapered roller is likely to tilt.

[0008] However, even if skew occurs once, it is possible to reduce the skew by reducing the load and rotational speed. By reducing the skew, seizure of the bearing and damage to the small flange of the inner ring can be suppressed. Therefore, after detecting the occurrence of skew, if deceleration or the like is performed to reduce the load and rotational speed, it is possible to continue using the bearing for a while.

[0009] The present invention provides a tapered roller bearing capable of detecting the skew of a tapered roller.

Means for Solving the Problem

[0010] The above object of the present invention is achieved by the following configuration. (1) An outer ring having an outer raceway surface on its inner peripheral surface, An inner ring having an inner raceway surface on its outer peripheral surface, A tapered roller rotatably provided between the outer raceway surface and the inner raceway surface, A sensor that detects that the axial distance of the space dynamically occupied by the tapered roller has increased due to the skew of the tapered roller, A tapered roller bearing comprising the above. (2) The tapered roller bearing according to (1), wherein the sensor detects contact between a member protruding radially from an extension line of the outer raceway surface or the inner raceway surface and the tail of the tapered roller. (3) The tapered roller bearing according to (1) or (2), wherein the sensor detects that a member protruding radially from an extension line of the outer raceway surface or the inner raceway surface has moved due to contact with the tail of the tapered roller.

Advantages of the Invention

[0011] According to the present invention, it is possible to detect and notify the occurrence of skew of the tapered roller.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0013] Hereinafter, each embodiment of the method for assembling a tapered roller bearing according to the present invention will be described in detail with reference to the drawings.

[0014] (First Embodiment) As shown in FIG. 1, a tapered roller bearing 10 according to the first embodiment includes an outer ring 11 having an outer ring raceway surface 11a on its inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on its outer peripheral surface, a plurality of tapered rollers 13 rotatably provided between the outer ring raceway surface 11a and the inner ring raceway surface 12a, and a cage 14 made of metal or resin for holding the plurality of tapered rollers 13 at predetermined intervals in the circumferential direction.

[0015] The inner ring 12 has a small flange portion 15 provided at the small-diameter side end portion of the inner ring 12 and a large flange portion 16 provided at the large-diameter side end portion of the inner ring 12. The small flange surface 15a of the small flange portion 15 is a surface that is close to the tail portion 13a which is the small-diameter side end portion of the tapered roller 13. Also, the large flange surface 16a of the large flange portion 16 is a surface that contacts the head portion 13b which is the large-diameter side end portion of the tapered roller 13.

[0016] The cage 14 is formed, for example, by press working an iron plate or injection molding of resin, and includes a small-diameter side annular portion 14a, a large-diameter side annular portion 14b coaxially arranged with the small-diameter side annular portion 14a, and a plurality of column portions 14c arranged at predetermined intervals (for example, substantially equal intervals) in the circumferential direction to connect the small-diameter side annular portion 14a and the large-diameter side annular portion 14b. A pocket portion 14d for rotatably holding the tapered roller 13 is formed between each pair of adjacent column portions 14c in the circumferential direction.

[0017] For example, by using two such tapered roller bearings 10 with outer ring rotation, it is applied to a structure for supporting the wheels of a vehicle, but the specific examples of the application target of the tapered roller bearing 10 are not particularly limited.

[0018] Furthermore, the tapered roller bearing 10 includes a sensor 20 that detects an increase in the axial distance of the space dynamically occupied by the tapered roller 13 due to the skew of the tapered roller 13. During operation of the tapered roller bearing 10, the tapered roller 13 rotates, but the phenomenon in which the tapered roller 13 tilts from its original axis of rotation is called skew. Due to the occurrence of skew, the space occupied by the tapered roller 13 while it is moving, that is, the dynamically occupied space, changes, and a phenomenon may occur in which the axial distance of the space increases. The sensor 20 is a device that captures such a phenomenon.

[0019] In the present embodiment, the sensor 20 is provided at a position on the inner ring 12 that axially overlaps with the small flange portion 15 of the inner ring 12. In particular, in the present embodiment, a part of the inner ring raceway surface 12a and the inner diameter surface 12b on the opposite side in the radial direction are removed to form a concave portion 12c. The sensor 20 is disposed in this concave portion 12c.

[0020] The sensor 20 can detect the contact between the tail portion 13a of the tapered roller 13 and the small flange portion 15. That is, when the axial distance of the space dynamically occupied by the tapered roller 13 increases due to the occurrence of skew, the tail portion 13a contacts the small flange portion 15. The sensor 20 detects this contact. In particular, in the present embodiment, since the sensor 20 is provided at a position axially overlapping with the small flange portion 15 and adjacent in the radial direction, the sensor 20 is disposed adjacent to the small flange portion 15, and the contact between the tail portion 13a and the small flange portion 15 can be detected with high accuracy.

[0021] As the sensor 20, for example, a temperature sensor that detects a temperature change of the small flange portion 15 when contacting the tail portion 13a, a strain sensor that detects a strain of the small flange portion 15 when contacting the tail portion 13a, a vibration sensor that detects vibration of the small flange portion 15, an acoustic emission sensor that detects deformation of the small flange portion 15, or the like may be applied. Also, the sensor 20 may be formed, for example, in an annular shape or a plurality of sensors may be arranged at equal intervals in the circumferential direction according to its type.

[0022] Note that the outer diameter of the small flange portion 15 of the inner ring 12 is designed to be larger than the maximum value of the inner diameter of the inscribed circle on the tail portion 13a side of the tapered roller 13 assembled to the cage 14. With such a design, the assembly of the tapered roller 13 and the cage 14 is prevented from separating from the inner ring 12. In a normal use state, the tail portion 13a of the tapered roller 13 and the side surface on the raceway surface side of the small flange portion 15 do not contact each other.

[0023] The tapered roller bearing 10 of the present embodiment can detect the skew of the tapered roller 13 and notify the user of the bearing, such as the driver of the vehicle, of the occurrence of skew before a serious situation such as seizure or damage to the small flange portion 15 of the inner ring 12 occurs. By this notification, the user can be prompted to decelerate, stop, etc. the tapered roller bearing 10. Thereby, the life of the tapered roller bearing 10 can be extended. As a result, devices such as vehicles using the tapered roller bearing 10 can be maintained under an appropriate plan, preventing the device from suddenly becoming unusable and improving the operating rate of the device.

[0024] (Second Embodiment) As shown in FIG. 2, in the second embodiment, the tapered roller bearings 10 of the present invention are combined in a double row and applied to a wheel bearing device 100 in a back-to-back arrangement. In the present embodiment, the hub has a hub ring 31 and a pair of inner rings 12A and 12B press-fitted into the hub ring 31. The hub ring 31 integrally has a wheel mounting flange 33 for mounting a wheel (not shown) at an end on the outboard side, which is the left side in the axial direction in the drawing. Further, a cylindrical small-diameter step portion 31b extending in the axial direction is formed on the outer periphery of the hub ring 31 via a shoulder 31a. In addition, hub bolts 33a for fixing the wheel are implanted in the wheel mounting flange 33. Note that with respect to the axial direction, the "outboard side" refers to the left side in FIGS. 2 to 5, which is the outside of the vehicle body when the vehicle bearing device 100 is assembled to an automobile. Conversely, the right side in FIGS. 2 to 5, which is the central side of the vehicle body when the vehicle bearing device 100 is assembled to an automobile, is referred to as the "inboard side" with respect to the axial direction.

[0025] The double-row tapered roller bearing 10 includes an outer ring 11 having a pair of outer ring raceway surfaces 11a1 and 11a2 on its inner peripheral surface, a pair of inner rings 12A and 12B having inner ring raceway surfaces 12a1 and 12a2 on their outer peripheral surfaces, a plurality of tapered rollers 13A and 13B rotatably provided in a double row between the outer ring raceway surfaces 11a1 and 11a2 and the inner ring raceway surfaces 12a1 and 12a2, and resin or metal cages 14A and 14B for holding the plurality of tapered rollers 13A and 13B at predetermined intervals in the circumferential direction.

[0026] Further, the outer ring 11 integrally has a vehicle body mounting flange 11b for attachment to a knuckle (not shown) on its outer peripheral surface. The inner ring 12A has a small flange portion 15A provided at the small-diameter side end of the inner ring 12A and a large flange portion 16A provided at the large-diameter side end of the inner ring 12A. Similarly, the inner ring 12B has a small flange portion 15B provided at the small-diameter side end of the inner ring 12B and a large flange portion 16B provided at the large-diameter side end of the inner ring 12B.

[0027] The tapered roller bearing 10 is press-fitted into the small-diameter step portion 31b of the hub ring 31 with a predetermined interference so that the large end surface of the outboard inner ring 12B abuts against the shoulder 31a of the hub ring 31. Then, it is fixed in a state where a predetermined preload is applied by a caulking portion 38 formed by plastically deforming the end portion of the small-diameter step portion 31b radially outward.

[0028] Furthermore, the tapered roller bearing 10 includes a sensor 20 for detecting that the axial distance of the space dynamically occupied by the tapered rollers 13A and 13B is extended due to the skew of the tapered rollers 13A and 13B. In the present embodiment, the sensor 20 is provided at a position on the inner ring 12A that is axially opposite to the small flange portion 15A with respect to the inner ring raceway surface 12a1. In particular, in the present embodiment, a cylindrical portion 12d having a diameter smaller than that of the small flange portion 15A and extending axially a part of the inner ring 12A is formed on the inner ring 12A axially opposite to the small flange portion 15A with respect to the inner ring raceway surface 12a1. The pair of sensors 20 are arranged on the outer peripheral surface of the cylindrical portion 12d with a transmitting portion 23 having a transmitting electrode for transmitting a signal from the sensor 20 interposed therebetween.

[0029] Furthermore, in the present embodiment, a spring 22, which is an elastic member, is disposed between the transmission unit 23 and the sensor 20 for the tapered roller bearing 10 on the outboard side. With the pair of inner rings 12A and 12B assembled to the hub ring 31, the sensor 20 is pressed axially against the small flange portion 15B of the inner ring 12B by the biasing force of the spring 22. As a result, the sensor 20 is in close contact with the small flange portion 15B, and the contact between the tail portion 13a2 and the small flange portion 15B can be detected with high precision. The specific example of the elastic member is not limited to a spring.

[0030] Therefore, the pair of sensors 20 can detect the contact between the tail portion 13a1 of the tapered roller 13A and the small flange portion 15A, or between the tail portion 13a2 of the tapered roller 13B and the small flange portion 15B. That is, when the axial distance of the space dynamically occupied by the tapered roller 13A or 13B extends due to the occurrence of skew, the tail portion 13a1 or 13a2 comes into contact with the small flange portion 15A or 15B. The sensor 20 detects this contact. Particularly in the present embodiment, since the pair of sensors 20 are provided at positions adjacent to the small flange portions 15A and 15B in the axial direction, the contact between the tail portion 13a1 and the small flange portion 15A, or between the tail portion 13a2 and the small flange portion 15B can be detected with high precision. Therefore, in the present embodiment, the small flange portions 15A and 15B are members that project radially from the extension lines of the inner ring raceway surfaces 12a1 and 12a2 of the present invention, and the sensors 20 and 20 detect the contact with the tail portions 13a1 and 13a2 of the tapered rollers 13A and 13B.

[0031] Furthermore, in the present embodiment, a receiving unit 24 having a receiving electrode for receiving a signal from the sensor 20 is provided on the inner peripheral surface of the outer ring 11 at a position facing the sensor 20 in the radial direction. In particular, the receiving unit 24 is connected to an external device via an electric wire 26 wired to a through hole 25 provided in the outer ring 11. Thereby, the receiving unit 24 can smoothly receive the signal from the sensor 20, that is, the skew detection signal, and smoothly transmit it to the external device via the electric wire 26, and can smoothly notify the detection of skew.

[0032] (Third Embodiment) As shown in Fig. 3, in the third embodiment as well, the tapered roller bearings 10 of the present invention are combined in a double row and applied to the wheel bearing device 100 with a back-to-back arrangement. Note that, except for the sensor peripheral portions of the tapered roller bearings 10, the wheel bearing device 100 has the same configuration as that shown in Fig. 2.

[0033] In the present embodiment, the small flange portions 15A and 15B are provided separately from, for example, the main body portions having the inner ring raceway surfaces 12a1 and 12a2 of the inner rings 12A and 12B, and are press-fitted into the main body portions with an interference fit under a relatively light pressure. As a result, when skew occurs in the tapered rollers 13A and 13B and they come into contact with the tail portions 13a1 and 13a2 of the tapered rollers 13A and 13B, the small flange portions 15A and 15B are provided in a state where they can move in the axial direction.

[0034] Also, in the outer ring 11, a proximity sensor 20A is provided at an intermediate position in the axial direction, for example, between a pair of outer ring raceway surfaces 11a1 and 11a2. The proximity sensor 20A can detect the axial movement of the small flange portions 15A and 15B when they come into contact with the tail portion 13a1 of the small flange portion 15A or the tail portion 13a2 of the small flange portion 15B.

[0035] In the case of this structure, when the axial movement amount of the small flange portions 15A and 15B is small (a state where there are portions with a large movement amount and portions with a small movement amount over the entire circumference), the proximity sensor 20A reacts intermittently. When the movement amount increases, the proximity sensor 20A reacts continuously. Therefore, the damage level of the wheel bearing device 100 can also be grasped accordingly. Also, the axial movement of the small flange portions 15A and 15B can temporarily prevent the progress of skew seizure.

[0036] (Fourth Embodiment) As shown in Fig. 4, in the fourth embodiment as well, the tapered roller bearings 10 of the present invention are combined in a double row and applied to the wheel bearing device 100 with a back-to-back arrangement. Except for the sensor peripheral portions of the tapered roller bearings 10, the wheel bearing device 100 has the same configuration as that of the wheel bearing devices 100 shown in Figs. 2 and 3.

[0037] In this embodiment, a pair of protrusions 17A and 17B are provided on the outer ring 11, and further, a pair of sensors 20 and 20 are provided on the outer ring 11 at positions axially opposite to the protrusions 17A and 17B with respect to the outer ring raceway surfaces 11a1 and 11a2. Thereby, when skew occurs in the tapered rollers 13A and 13B, the protrusions 17A and 17B come into contact with the trailing ends 13a1 and 13a2 of the tapered rollers 13A and 13B. The sensors 20 and 20 detect this contact. Therefore, in this embodiment, the protrusions 17A and 17B are members that protrude radially from the extension lines of the outer ring raceway surfaces 11a1 and 11a2 of the present invention, and the sensors 20 and 20 detect contact with the trailing ends 13a1 and 13a2 of the tapered rollers 13A and 13B.

[0038] The protrusions 17A and 17B are provided at positions such that the distance between the trailing ends 13a1 and 13a2 and the protrusions 17A and 17B is smaller than the distance between the trailing ends 13a1 and 13a2 and the small flange portions 15A and 15B in the normal use state. Therefore, when skew occurs, the trailing ends 13a1 and 13a2 of the tapered rollers 13A and 13B come into contact with the protrusions 17A and 17B before coming into contact with the small flange portions 15A and 15B. Thereby, the sensors 20 and 20 can detect the skew promptly.

[0039] The sensor 20 is connected to an external device via an electric wire 26 wired in a through hole 25 provided in the outer ring 11. Thereby, the sensor 20 can smoothly receive a signal, that is, a skew detection signal, and smoothly transmit it to the external device via the electric wire 26, and can smoothly notify the detection of the skew. In this case, the transmission unit 23 and the reception unit 24 in FIG. 2 are unnecessary, the configuration can be simplified, and the cost can be reduced.

[0040] (Fifth Embodiment) As shown in FIG. 5, the third embodiment is also an application in which the tapered roller bearings 10 of the present invention are combined in a double row and applied to the wheel bearing device 100. Except for the sensor peripheral portion of the tapered roller bearing 10, it has the same configuration as the wheel bearing device 100 in FIGS. 2 to 4.

[0041] In this embodiment, the projections 17A and 17B are provided separately from, for example, a main body portion having outer raceway surfaces 11a1 and 11a2 of the outer race 11, and are press-fitted into the main body portion with an interference fit under a relatively light pressure. As a result, when skews occur in the tapered rollers 13A and 13B and the projections 17A and 17B come into contact with the tail portions 13a1 and 13a2 of the tapered rollers 13A and 13B, the projections 17A and 17B are provided in a state where they are axially movable.

[0042] Also, in the outer race 11, a proximity sensor 20A is provided at an intermediate position in the axial direction, for example, between the inner raceway surface 12a1 and the inner raceway surface 12a2. The proximity sensor 20A can detect the axial movement of the projections 17A and 17B when they come into contact with the tail portions 13a1 and 13a2.

[0043] In the case of this structure, while the axial movement amount of the projections 17A and 17B is small (a state where there are areas with a large movement amount and areas with a small movement amount over the entire circumference), the proximity sensor 20A reacts intermittently. When the movement amount increases, the proximity sensor 20A reacts continuously. Therefore, the level of damage to the wheel bearing device 100 can also be grasped. Also, with a simple configuration, the sensor 20 can smoothly receive a signal, that is, a skew detection signal, and smoothly transmit it to an external device via the electric wire 26, and can smoothly notify the detection of skew. In this case, the transmission unit 23 and the reception unit 24 in FIG. 2 are unnecessary, and the configuration can be simplified and the cost can be reduced.

[0044] Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, etc. In addition, the material, shape, dimensions, numerical values, form, number, arrangement location, etc. of each component in the above-described embodiment are arbitrary as long as the present invention can be achieved, and are not limited.

[0045] In the embodiments of FIGS. 2 to 5, the hub is composed of a hub ring 31 and a pair of inner rings 12A and 12B. However, in the present invention, the hub ring may be integrally formed with the outboard inner ring, and the hub may be composed of the hub ring and the inboard inner ring.

[0046] In the above embodiment, as a member that protrudes radially from the extension line of the outer ring raceway surface or the inner ring raceway surface and the sensor detects contact with the tail of the tapered roller, a small flange portion provided integrally or separately with the inner ring, or a protrusion provided integrally or separately with the outer ring is described. However, in the present invention, the member that protrudes radially from the extension line of the outer ring raceway surface or the inner ring raceway surface is not limited to this, as long as the sensor is configured to detect contact with the tail of the tapered roller.

Explanation of Reference Numerals

[0047] 10 Tapered roller bearing 11 Outer ring 11a, 11a1, 11a2 Outer ring raceway surface 12, 12A, 12B Inner ring 12a, 12a1, 12a2 Inner ring raceway surface 13, 13A, 13B Tapered roller 13a, 13a1, 13a2 Tail 13b Head 14 Cage 15, 15A, 15B Small flange portion 16, 16A, 16B Large flange portion 17A, 17B Protrusion 20 Sensor 20A Proximity sensor 22 Spring (elastic member) 23 Transmitter 24 Receiver 25 Through hole 26 Electric wire

Claims

Claim 1 an outer ring having an outer raceway surface on its inner peripheral surface, an inner ring having an inner raceway surface on its outer peripheral surface, a tapered roller rotatably provided between the outer raceway surface and the inner raceway surface, a sensor that detects that the axial distance of the space dynamically occupied by the tapered roller has increased due to the skew of the tapered roller, comprising: wherein the sensor detects contact between a member that projects radially from a line extending the outer raceway surface or the inner raceway surface and the tail of the tapered roller, a tapered roller bearing

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