JP2011178314A - Axle bearing for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axle bearing for a vehicle superior in durability, without reducing detection accuracy when having a rotation sensor, by restraining heat transfer of heating in braking. <P>SOLUTION: This axle bearing for the vehicle includes an inner ring, an outer ring and a rolling element, wherein a flange part is integrated with at least one of the outer ring and a wheel hub, and an axle is fitted to the inner ring. In the axle bearing for the vehicle, a flange part is formed of a laminated body of a carbon fiber prepreg formed by orienting carbon fibers in one direction in a plane shape and binding the carbon fibers by resin or the carbon fiber prepreg bound by the resin by braiding the carbon fibers in a plane shape, and a transfer surface is made of metal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle axle bearing represented by a hub unit bearing of an automobile, and more particularly to a technique for eliminating the influence of heat conduction.

  In automobile hub unit bearings, the inner and outer rings are made of metal such as bearing steel. However, they are heavy, disadvantageous in terms of fuel consumption, and expensive, so the transfer surfaces and flanges of the inner and outer rings are expensive. Is formed with a base portion made of a thin metal plate, and the base portion is further reinforced with a composite material in which a reinforcing fiber is blended with a synthetic resin (see Patent Document 1).

  However, since the brake rotor is fastened to the hub unit bearing via the flange portion, frictional heat generated during braking is transferred through the flange portion, and the temperature rise of the entire hub unit accompanying rotation is promoted. As the temperature rises, the sealed grease deteriorates, resulting in increased rotational torque, abnormal noise, vibration, etc., resulting in decreased bearing performance and eventually seizure. Bearing function is lost. In Patent Document 1, since the flange portion is made of metal, it is easy to conduct heat, and an increase in bearing temperature cannot be suppressed.

  Some hub unit bearings include a rotation sensor for detecting the rotational speed of the axle. A rotation sensor is generally configured by attaching a magnetic encoder to the outer peripheral surface of a metal slinger attached to an inner ring and arranging the magnetic sensor so as to face the magnetic encoder (see FIG. 1). Therefore, the accuracy of the magnetic encoder mounting position is required, but as described above, when frictional heat is applied during braking and the temperature of the inner ring and outer ring rises, the slinger attached to the inner ring undergoes thermal expansion. The magnetic encoder mounting position changes slightly, affecting the detection accuracy.

No. 7-54658

  The present invention has been made in view of the above circumstances, and provides a vehicle axle bearing for a vehicle that suppresses heat transfer during braking, has excellent durability, and has no deterioration in detection accuracy when a rotation sensor is provided. The purpose is to do.

In order to solve the above problems, the present invention provides the following vehicle axle bearings.
(1) In a vehicle axle bearing that includes an inner ring, an outer ring, and rolling elements, the flange portion is integrated with at least one of the outer ring and the wheel hub, and the axle is fitted to the inner ring, the transfer surface is made of metal, A vehicle axle bearing characterized in that the flange portion is formed of a laminate of carbon fiber prepregs.
(2) The carbon fiber prepreg is obtained by orienting carbon fibers in a flat direction in one direction and binding them with a resin, and the carbon fibers are screwed to the flange portion with respect to the axis of the mounting bolt. The vehicle axle bearing according to (1) above, wherein the vehicle axle bearings are stacked so as to intersect vertically between adjacent carbon fiber prepregs.
(3) The carbon fiber prepreg is formed by braiding carbon fibers into a flat shape and binding them with a resin, and the carbon fibers are perpendicular to the axis of the mounting bolt screwed into the flange portion. The vehicle axle bearing according to (1) above, wherein the vehicle axle bearing is laminated.
(4) The vehicle axle bearing according to any one of (1) to (3) above, wherein the carbon fiber content in the carbon fiber prepreg is 10 to 80% by mass.
(5) The tensile strength of carbon fiber is 3 to 8.5 GPa, the tensile modulus is 220 to 700 GPa, and the elongation is 0.5 to 2.2%. The vehicle axle bearing according to any one of the preceding claims.
(6) The vehicle axle bearing according to any one of (1) to (5) above, wherein the resin in the carbon fiber prepreg is an epoxy resin, a phenol resin, a polyamide resin, or a polypropylene resin.
(7) The vehicle axle bearing according to any one of (1) to (6) above, wherein a laminate of carbon fiber prepregs is fastened to an outer ring or a wheel hub with a center nut.
(8) The vehicle axle bearing according to any one of (1) to (6) above, further comprising a sensor for detecting the rotational speed of the axle.

  In the vehicle axle bearing of the present invention, the flange portion is formed of a laminated body of carbon fiber prepregs, and the transfer surface is made of metal, so that heat transfer through the flange portion is suppressed without affecting the rotation characteristics, and thus long. Life is reached. Moreover, when it is set as the structure provided with a rotation sensor, there is no fall of detection accuracy. Furthermore, the weight can be reduced.

1 is a cross-sectional view showing a hub unit with a rotation sensor, which is an example of a vehicle axle bearing according to the present invention. It is a schematic diagram which shows an example of the lamination | stacking mode of a carbon fiber prepreg. It is a schematic diagram for demonstrating the relative position of the carbon fiber and attachment bolt in the laminated body of a carbon fiber prepreg. It is a schematic diagram which shows the structure which fixed the flange part with the center nut.

  Hereinafter, a hub unit bearing with a rotation sensor will be described in detail with reference to the present invention.

  The hub unit bearing O of the present embodiment is used for a drive wheel, and is arranged to roll freely in an outer ring 1 that is a fixed wheel and a hub 3 that is a rotating wheel, and an annular space 13 between the outer ring 1 and the hub 3. A plurality of rolling elements 10, sealing devices 12 a and 12 b that seal the annular space 13, and a magnetic encoder 20 that rotates together with the hub 3. Further, a magnetic sensor (not shown) is disposed opposite to the magnetic encoder 20, and the magnetic encoder 20 is rotated together with the rotation of the wheel to detect a magnetic field change synchronized with the rotation of the wheel.

  The hub 3 includes a hollow hub wheel 4, and the hub wheel 4 is an end portion on the outboard side of the outer peripheral surface (an end portion on the outer side in the vehicle width direction in the assembled state in the automobile: the left end portion in FIG. 1). Has a wheel mounting flange 7 extending radially outward. A plurality of mounting bolts 7a for mounting a wheel, a brake rotor, and the like (not shown) constituting the wheel are implanted in the wheel mounting flange 7 at substantially equal intervals in the circumferential direction.

  A small-diameter step portion 4a is formed at an end portion on the inboard side of the hub wheel 4 (the end portion on the inner side in the vehicle width direction in the assembled state in the automobile: the right end portion in FIG. 1). 5 is fitted. An inner ring raceway surface 9 is formed on the outer circumferential surface of the inner ring 5, and an inner ring raceway surface 9 is also formed on the outer circumferential surface of the intermediate portion in the axial direction of the hub ring 4.

  An outer ring raceway surface 8 corresponding to the inner ring raceway surface 9 of the hub ring 4 and an outer ring raceway surface 8 corresponding to the inner ring raceway surface 9 of the inner ring 5 are formed on the inner peripheral surface of the outer ring 1. A suspension device mounting flange 2 extending radially outward is provided at the end of the outer ring 1 on the side away from the outer ring 1. Although illustration is omitted, a knuckle is attached to the suspension device mounting flange 2 with a mounting bolt.

  A plurality of rolling elements 10 are arranged between the double row inner ring raceway surface 9 and the double row outer ring raceway surface 8 so as to be able to roll in the circumferential direction via a cage 11. In the illustrated example, a ball is used as the rolling element 10, but in the case of a wheel supporting hub unit bearing that is heavy in weight, a tapered roller may be used as the rolling element 10.

  Sealing devices 12 a and 12 b are provided between the end portion on the outboard side of the outer ring 1 and the hub wheel 4, and between the end portion on the inboard side of the outer ring 1 and the inner ring 5, respectively. The sealing device 12 a includes a slinger 14 fitted to the inner peripheral surface of the end portion of the outer ring 1 on the outboard side, and a seal portion 15 that is bonded and fixed to the slinger 14 and slidably contacts the hub wheel 4.

  On the other hand, the sealing device 12b includes a first slinger 16 fitted to the outer peripheral surface of the inner ring 5, a second slinger 17 fitted to the inner peripheral surface of the end portion of the outer ring 1 on the inboard side, It has a seal portion 18 that is adhered and fixed to the slinger 16 and is in sliding contact with the second slinger 17. The seal portion 18 is formed of a rubber material, and prevents leakage of the encapsulated grease and prevents entry of dust, water, muddy water, and the like from the outside into the annular space 13.

  In the present invention, the transfer surfaces, that is, the outer ring raceway surface 8 and the inner ring raceway surface 9 are made of steel used for normal bearings such as SUJ2, and the flange portions, that is, the wheel mounting flange 7 of the hub wheel 4 and the suspension of the outer ring 1 are made. The apparatus mounting flange 2 (the portion indicated by a cross hatch in the figure) is formed of a laminate of carbon fiber prepregs.

  The carbon fiber prepreg is obtained by laminating a sheet (unidirectional prepreg) in which carbon fibers are planarly oriented in one direction and bound with a resin. At that time, as schematically shown in FIG. 2, the carbon fibers 100 are (a) → (b) → (c) → (d) between adjacent carbon fiber prepregs (upper and lower in the example of the figure). In this way, the layers are laminated so as to intersect at a predetermined angle (for example, 45 °). The lamination can be performed by hot pressing or autoclave.

  The carbon fiber prepreg may be a laminate of sheet-like materials (braided prepreg) obtained by braiding carbon fibers in a flat shape and binding them with a resin.

  There are no restrictions on the type and diameter of the carbon fiber, but considering the practical strength of the laminate made of carbon fiber prepreg, the tensile strength is 3 to 8.5 GPa, the tensile modulus is 220 to 700 MPa, and the elongation is Is preferably 0.5 to 2.2%. Moreover, as for content of the carbon fiber in a carbon fiber prepreg, 10-80 mass% is preferable. When the carbon fiber content is less than 10% by mass, a laminate composed of carbon fiber prepreg does not have the required strength. On the other hand, when the carbon fiber content exceeds 80% by mass, the amount of the resin is relatively decreased, and the adhesiveness between the prepregs is lowered. A preferable carbon fiber content is 60 to 75% by mass.

  The resin for binding the carbon fibers is not limited, and a thermosetting resin such as an epoxy resin or a phenol resin, or a thermoplastic resin such as a polyamide resin or a polypropylene resin can be used.

  Further, as schematically shown in FIG. 3, the carbon fiber prepreg is laminated so that the carbon fiber 100 is perpendicular to the axis C of the mounting bolt 7a.

  And the laminated body of carbon fiber prepreg is made into a flange member corresponding to the wheel mounting flange 7 by opening a bolt hole through which the mounting bolt 7 a is inserted, and is fixed to the outer peripheral surface of the hub wheel 4. Similarly, a flange member corresponding to the suspension device mounting flange 2 can be formed of a laminate of carbon fiber prepregs. The fixing method of the flange member and the hub ring 4 or the outer ring 1 can be bonded using an adhesive capable of bonding to a metal in accordance with the resin used for the carbon fiber prepreg. Further, as shown in FIG. 4, the center nut 30 can be used to fix the hub wheel 4. Furthermore, you may use an adhesive agent and the center nut 30 together. Further, knurling serration processing may be applied to the fixing surface of the hub wheel 4.

  Since the hub unit bearing O has a transfer surface made of metal, the bearing rotation characteristics are maintained at the same level as the conventional one. In addition, since the suspension mounting flange 2 and the wheel mounting flange 7 are formed of carbon fiber prepreg, the strength and weight can be reduced, and the carbon fiber prepreg has significantly lower thermal conductivity than metal. Heat generated during braking is not transferred to the hub wheel 4 through the wheel mounting flange 7, and an increase in bearing temperature can be suppressed. Therefore, there is no thermal deterioration of the encapsulated grease, further no thermal expansion of the slinger 16, no positional deviation of the magnetic encoder 20, and a reduction in rotational accuracy can be prevented.

  Hereinafter, although an Example and a comparative example are given and demonstrated further, this invention is not restrict | limited at all by this.

Example 1
Carbon fibers (tensile strength 5000 MPa, tensile elastic modulus 235 GPa, elongation 1.9%) were arranged in a plane and bound with an epoxy resin to produce a unidirectional prepreg. The unidirectional prepreg has a carbon fiber content of 75 mass% and an epoxy resin content of 25 mass%. And as shown in FIG. 2, this carbon fiber prepreg was laminated | stacked so that carbon fiber might cross at 45 degrees, and it hot-pressed, and produced the laminated body.

  A rolling bearing for wheel support “No. 28BWK19” manufactured by Nippon Seiko Co., Ltd. was improved, and the flange member made of the above laminate was fixed to the hub wheel as a wheel mounting flange using an adhesive and a center nut. The inner ring and ball are made of SUJ2, and the outer ring is made of S53CG (carbon steel).

  And the brake rotor of a brake system was bolted to the flange member, and it was set as the test bearing A. In addition, when tightening the bolt, the fixing force was increased by bonding with an epoxy adhesive.

(Comparative Example 1)
A rolling bearing for wheel support “Nippon No. 28BWK19” manufactured by NSK Ltd. was used as it was, and a brake rotor was fastened to the wheel mounting flange to obtain a test bearing B.

(Life test)
Insert the axle into test bearing A and test bearing B, adjust the brake disc temperature to 130 ° C, apply axial load 8820N, rotate the axle at 100 rpm, and constantly measure vibration during rotation with a vibrometer. and regards the rotation time until the measured value exceeds a predetermined value and the rotation life was determined L ₁₀ life based on Weibull distribution function. The results are shown in Table 1.

  In addition, the inner ring surface temperature was measured during rotation. The results are also shown in Table 1.

  As shown in Table 1, by forming the flange portion with a laminate of carbon fiber prepregs, heat transfer through the brake rotor is suppressed, and the life is prolonged.

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Suspension apparatus attachment flange 3 Hub 4 Hub ring 5 Inner ring 7 Wheel attachment flange 10 Rolling elements 12a and 12b Sealing device 16 First slinger 17 Second slinger 18 Seal part 20 Magnetic encoder 30 Center nut 100 Carbon fiber

Claims (8)

In a vehicle axle bearing that includes an inner ring, an outer ring, and rolling elements, the flange portion is integrated with at least one of the outer ring and the wheel hub, and the axle is fitted to the inner ring.
A vehicle axle bearing having a transfer surface made of metal and a flange portion formed of a laminate of carbon fiber prepregs.   A carbon fiber prepreg is a carbon fiber that is oriented in one direction in a plane and bound with a resin, and the carbon fiber is adjacent to the axis of the mounting bolt that is screwed to the flange portion. The vehicular axle bearing according to claim 1, wherein the vehicular axle bearings are laminated so as to intersect with each other.   The carbon fiber prepreg is obtained by braiding carbon fibers in a flat shape and binding them with a resin, and the carbon fibers are laminated so as to be perpendicular to the axis of the mounting bolt screwed into the flange portion. The vehicle axle bearing according to claim 1, wherein the vehicle axle bearing is provided.   The vehicle axle bearing according to any one of claims 1 to 3, wherein the carbon fiber prepreg has a carbon fiber content of 10 to 80 mass%.   The tensile strength of carbon fiber is 3 to 8.5 GPa, the tensile elastic modulus is 220 to 700 GPa, and the elongation is 0.5 to 2.2%. 5. Vehicle axle bearings.   6. The vehicle axle bearing according to claim 1, wherein the resin in the carbon fiber prepreg is an epoxy resin, a phenol resin, a polyamide resin, or a polypropylene resin.   The vehicle axle bearing according to any one of claims 1 to 6, wherein a laminate of carbon fiber prepregs is fastened to an outer ring or a wheel hub by a center nut.   The vehicle axle bearing according to any one of claims 1 to 6, further comprising a sensor for detecting the rotational speed of the axle.

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