JP2011240831A - Wheel axle bearing for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel axle bearing for vehicle which suppresses heat transfer when braking, is excellent in durability and without deterioration of detection accuracy when a rotary sensor is included.SOLUTION: The wheel axle bearing for vehicle includes: an inward annular member; an outward annular member; and a rolling body; wherein a flange for attaching wheel is joined to inward annular member, a flange for attaching knuckle of a vehicle body is joined to the outward annular member and a wheel axle is fitted into the inward annular member. In the wheel axle bearing for vehicle, the inward annular member and the outward annular member are made of a metal, at least the flange for attaching wheel of the flange for attaching wheel and the flange for attaching knuckle is made of carbon fiber reinforced resin, is an annular member having a bolt insertion hole for inserting a bolt for attaching a wheel or a knuckle, and is joined to an annular vertical piece projecting to the outer peripheral plane of the inward annular member or to an annular vertical piece projecting to the outer peripheral plane of the outward annular member by fastening means at a plurality of points.

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, these conventional hub unit bearings do not consider heat conduction. Further, 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 increase 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. Loss of bearing function can be seen in severe endurance tests. In Patent Document 1, since there is a metal path between the brake rotor and the bearing portion, heat transfer is easy, and the bearing temperature is likely to rise, so that the bearing performance is reduced, and the brake is repeatedly repeated at short intervals. It can be seen in such a severe endurance test.

  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. Thus, the mounting position of the magnetic encoder may change slightly and affect 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) An inner annular member, an outer annular member, and a rolling element are provided, and a wheel mounting flange and a knuckle mounting flange of a vehicle body are joined to the inner annular member and the outer annular member, respectively. In a vehicle axle bearing in which an axle is fitted to a member,
The inner annular member and the outer annular member are made of metal,
At least the wheel mounting flange of the wheel mounting flange and the knuckle mounting flange is made of carbon fiber reinforced resin, and is an annular member having a bolt insertion hole for inserting a wheel or knuckle mounting bolt. An axle bearing for a vehicle, characterized in that it is joined to an annular standing piece projecting on the outer circumferential surface of the annular member or an annular standing piece projecting on the outer circumferential surface of the outer annular member by fastening means at a plurality of locations.
(2) At least the wheel mounting flange of the wheel mounting flange and the knuckle mounting flange and the annular upright piece each have a plurality of through holes for joining, and screws or The vehicle axle bearing according to (1), wherein the vehicle axle bearing is joined by a rivet.
(3) The vehicle axle bearing according to (1) or (2) above, wherein the bolt insertion hole and the joining through hole are arranged with a phase shifted.
(4) Carbon fiber reinforced resin laminates carbon fiber prepregs that are impregnated with resin by aligning the carbon fibers in a plane and in one direction so as to intersect between adjacent carbon fiber prepregs, and curing the resin The vehicle according to any one of (1) to (3) above, wherein the carbon fiber is oriented so as to be perpendicular to the bolt insertion hole. Axle bearing.
(5) The carbon fiber reinforced resin is obtained by laminating a carbon fiber prepreg obtained by braiding carbon fibers into a flat shape and impregnating the resin, and heat-curing the resin, and the carbon fibers are bolt insertion holes. The vehicle axle bearing according to any one of (1) to (3) above, wherein the vehicle axle bearing is oriented so as to be perpendicular to the vertical axis.
(6) The vehicle axle bearing according to any one of (1) to (5) above, wherein the carbon fiber content in the carbon fiber prepreg is 10 to 80% by mass.
(7) The tensile strength of the 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%. (1) to (6) above The vehicle axle bearing according to any one of the preceding claims.
(8) The vehicle axle according to any one of (1) to (7) above, wherein the resin used for the carbon fiber prepreg is an epoxy resin, a phenol resin, a polyamide resin, or a polypropylene resin. bearing.
(9) The vehicle axle bearing according to any one of (1) to (8) above, further comprising a sensor for detecting the rotational speed of the axle.

  In the vehicle axle bearing of the present invention, the wheel mounting flange is formed of carbon fiber reinforced resin and is integrally joined to the inner annular member, so that heat transfer through the wheel mounting flange is suppressed and the service life is extended. Further, since the inner annular member and the outer annular member are made of metal and the transfer surface is also made of metal, the rotation characteristics are not affected. Further, when the rotation sensor is provided, the detection accuracy is not lowered. 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 an AA arrow line view of FIG. 1, and is a figure which shows an example of arrangement | positioning with the through-hole for joining and a bolt penetration hole. It is an AA arrow line view of FIG. 1, and is a figure which shows the other example of arrangement | positioning with the through-hole for joining and a bolt penetration hole. 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 in a carbon fiber reinforced resin, and a bolt insertion hole. It is sectional drawing which shows an example of a bolt insertion hole. It is sectional drawing (A) and BB arrow line view (B) which show the other example of a bolt penetration hole. It is sectional drawing (A) and BB arrow line view (B) which show the other example of a bolt penetration hole.

  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 for a drive wheel, and rolls into an outer ring 1 that is an outer annular member, a hub 3 that is an inner annular member, and an annular space 13 between the outer ring 1 and the hub 3. A plurality of rolling elements 10 that are freely arranged, 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 are provided. An axle (not shown) is fitted into the axle insertion hole 200 at the center of the hub wheel 4. 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). The wheel mounting flange 7 extends radially outward. The wheel mounting flange 7 has bolt insertion holes 7a for inserting bolts 30 for mounting a wheel and a brake rotor (not shown) constituting the wheel on the side of the outboard side at substantially equal intervals in the circumferential direction. Several are planted.

  A small-diameter step portion 4A is formed on the inboard side end portion 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 knuckle mounting flange 2 extending radially outward is provided at the end of the outer ring 1 on the side away from the outer ring 7. Although not shown, the knuckle mounting flange 2 is formed with a bolt insertion hole 2a for inserting a knuckle mounting bolt (not shown).

  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 outer ring 1 and the hub ring 4 are made of steel used for normal bearings such as SUJ2, and the raceway surfaces 8 and 9 are made of metal, and the wheel mounting flange 7 and the knuckle mounting flange 2 ( In the figure, at least the wheel mounting flange 7 of the cross hatch) is formed of carbon fiber reinforced resin as will be described later, the knuckle mounting flange 2 is the outer ring 1, and the wheel mounting flange 7 is the hub wheel 4. Join. By forming the knuckle mounting flange 2 from carbon fiber reinforced fiber, the weight can be further reduced. In this embodiment, both the wheel mounting flange 7 and the knuckle mounting flange 2 are reinforced with carbon fiber. The example formed with resin is shown.

  When the hub wheel 4 and the wheel mounting flange 7 are joined, the hub wheel 4 is processed to provide an annular standing piece 4a on the outer peripheral surface, and a joining through hole 4b penetrating the standing piece 4a is formed. . On the other hand, the wheel mounting flange 7 is provided with a stepped portion 7b that engages with the upright piece 4a, and a joining through hole 7c that passes through the stepped portion 7b is formed. Then, a screw or a rivet (not shown) may be inserted and fastened through the joining through hole 4b of the upright piece 4a and the joining through hole 7c of the stepped portion 7b. In addition, joining strength can be improved more by attaching the standing piece 4a and the step part 7b with an adhesive agent, and fastening with a screw or a rivet. For bonding, an adhesive capable of bonding to metal is used in accordance with the resin used for the carbon fiber prepreg.

  At that time, as shown in FIG. 2 (viewed along arrow AA in FIG. 1), the through hole 4c for joining the vertical piece 4a of the hub wheel 4, the through hole 7c for joining the wheel mounting flange 7, and the wheel mounting flange 7 bolt insertion holes 7a may be arranged in phase with each other, that is, arranged on the same radius r, or, as shown in FIG. 3, joining through holes 4b and 7c and bolt insertion holes The holes 7a may be arranged so as to be out of phase, that is, not aligned on the same radius r. The joining through hole 7c and the bolt insertion hole 7a of the wheel mounting flange 7 are formed by opening these holes in the carbon fiber reinforced resin, and the carbon fibers are cut when the holes are formed. Therefore, by arranging the phases out of phase, the portion where the carbon fiber is cut is also separated, which is advantageous in terms of strength.

  On the other hand, the outer ring 1 and the knuckle mounting flange 2 are joined by processing the outer ring 1 and providing an annular standing piece 1a on the outer peripheral surface thereof, and also forming a joining through hole 1b penetrating the standing piece 1a. . The knuckle mounting flange 2 is provided with a stepped portion 2b that engages with the upright piece 1a, and is formed with a joining through hole 2c that passes through the stepped portion 2b. Then, a screw or rivet (not shown) is inserted and fastened through the joining through hole 1b of the upright piece 1a and the joining through hole 2c of the stepped portion 2b. In joining the outer ring 1 and the knuckle mounting flange 2 as well, it is preferable to dispose the joining through holes 1b and 2c and the bolt insertion hole 2a out of phase.

  The carbon fiber reinforced resin is obtained by laminating a sheet-like carbon fiber prepreg (unidirectional prepreg) in which carbon fibers are planarly oriented in one direction and impregnated with the resin, and the resin is cured. At that time, as schematically shown in FIG. 4, 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 °). In addition, hardening can be performed by a hot press or an autoclave.

  The carbon fiber prepreg may be a sheet (braided prepreg) in which carbon fibers are braided into a flat shape and impregnated with a resin.

  The carbon fiber is not limited, but considering the practical strength of the carbon fiber reinforced resin, the tensile strength is 3 to 8.5 GPa, the tensile modulus is 220 to 700 GPa, and the elongation is 0.5 to 2. What is 2% is preferable. The carbon fiber preferably has an average fiber diameter of 5 to 21 μm, and more preferably 7 to 15 μm. With carbon fibers having an average fiber diameter of less than 5 μm, the fibers are too thin and the strength per one is low, so that stable production becomes difficult and the cost is greatly increased, so the feasibility is low. On the other hand, carbon fibers having an average fiber diameter of more than 21 μm are not preferable because the strength per one fiber is increased, but the fibers become thick and difficult to cope with deformation during molding. Furthermore, the carbon fiber content in the carbon fiber prepreg is preferably 10 to 80% by mass. If the carbon fiber content is less than 10% by mass, the carbon fiber reinforced resin cannot exhibit the required strength. On the other hand, when the content of the carbon fiber exceeds 80% by mass, the amount of the resin is relatively decreased, and a resin non-impregnated portion (void) is generated, and there is a possibility that the destruction occurs from the inside. A preferable carbon fiber content is 60 to 75% by mass.

  In addition, there is no restriction | limiting in resin used for a carbon fiber prepreg, Thermosetting resins, such as an epoxy resin and a phenol resin, Thermoplastic resins, such as a polyamide resin and a polypropylene resin, can be used.

  Further, as schematically shown in FIG. 5, the carbon fiber prepreg is laminated so that the carbon fibers 100 are perpendicular to the bolt insertion holes 7a.

  Furthermore, as shown in FIG. 6, a screw groove 40 that is screwed with a screw portion of the bolt 30 is formed on the inner peripheral surface of the bolt insertion hole 7 a of the wheel mounting flange 7. In order to form the screw groove 40, a sleeve 45 made of metal and having the screw groove 40 formed on the inner peripheral surface is inserted into a through hole provided in the carbon fiber reinforced resin, and the metal made in the gap with the carbon fiber reinforced resin. The wedge 46 is inserted to fix the sleeve 45 in the carbon fiber reinforced resin. As the metal, aluminum or stainless steel is suitable.

  Further, as shown in FIG. 7, the end of the sleeve 45 is provided with an elliptical enlarged diameter stepped portion 47 having a long diameter in the circumferential direction of the flange 7, thereby increasing the strength of the sleeve itself and the entire flange. it can.

  Further, as shown in FIG. 8, it is also possible to project a part of the upright piece 4a outward and to form a bolt insertion hole 7a in the projecting portion 4c. Then, the sleeve 45 is inserted into the insertion hole that communicates the protruding portion 4 c and the carbon fiber reinforced resin, and the other end is fixed by the annular outer screw 48. Instead of the external screw 48, the wedge 46 may be used as described above. Such a protrusion 4c can also increase the strength of the sleeve itself and the entire flange.

  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 knuckle mounting flange 2 and the wheel mounting flange 7 are formed of carbon fiber reinforced resin, it is possible to achieve high strength and light weight, and the carbon fiber reinforced resin has a greater thermal conductivity than metal. Therefore, heat generated during braking does not transfer 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 there is no thermal expansion of the first 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 5 GPa, tensile 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 this carbon fiber prepreg was laminated | stacked so that carbon fiber might cross at 45 degrees, as shown in FIG. 4, and it hot-pressed, and produced carbon fiber reinforced resin. Then, as shown in FIG. 3, a step portion is formed in the carbon fiber reinforced resin, and a through hole for joining and a bolt insertion hole are formed so that the phases are shifted, and a wheel mounting flange and a knuckle mounting flange are prepared. did.

  In addition, the wheel bearing rolling bearing "Nominal number 28BWK19" manufactured by NSK Ltd. has been improved. Formed. The inner ring and ball are made of SUJ2, and the outer ring is made of S53CG (carbon steel).

  Then, the wheel mounting flange was engaged with the vertical piece of the hub wheel, the knuckle mounting flange was engaged with the vertical piece of the outer ring, and a screw was inserted into the through hole for joining and fastened. Further, the brake rotor of the brake system was bolted to the wheel mounting flange to obtain a 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 “No. 28BWK19” manufactured by NSK Ltd. was used as it was, and a brake rotor was fastened to a 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 to 130 ° C, apply axial load 8820N, rotate the axle at 1000 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 wheel mounting flange with a carbon fiber reinforced resin, heat transfer through the brake rotor is suppressed, and the service life is extended.

DESCRIPTION OF SYMBOLS 1 Outer ring 1a Standing piece 1b Joining through hole 2 Knuckle mounting flange 2a Bolt insertion hole 2b Step part 2c Joining through hole 3 Hub 4 Hub wheel 4a Standing piece 4b Joining through hole 5 Inner ring 7 Wheel mounting flange 7a Bolt insertion Hole 7b Stepped portion 7c Joining through hole 10 Rolling elements 12a, 12b Sealing device 16 First slinger 17 Second slinger 18 Seal portion 20 Magnetic encoder 30 Bolt 100 Carbon fiber

Claims (9)

An inner annular member, an outer annular member, and a rolling element are provided, a wheel mounting flange and a knuckle mounting flange of a vehicle body are joined to the inner annular member, and an axle is connected to the inner annular member. In a vehicle axle bearing to which is fitted,
The inner annular member and the outer annular member are made of metal,
At least the wheel mounting flange of the wheel mounting flange and the knuckle mounting flange is made of carbon fiber reinforced resin, and is an annular member having a bolt insertion hole for inserting a wheel or knuckle mounting bolt. An axle bearing for a vehicle, characterized in that it is joined to an annular standing piece projecting on the outer circumferential surface of the annular member or an annular standing piece projecting on the outer circumferential surface of the outer annular member by fastening means at a plurality of locations.   At least the wheel mounting flange of the wheel mounting flange and the knuckle mounting flange and the annular upright piece each have a plurality of through holes for bonding, and are joined by screws or rivets through the bonding through holes. 2. The vehicle axle bearing according to claim 1, wherein the vehicle axle bearing is provided.   The vehicular axle bearing according to claim 1 or 2, wherein the bolt insertion hole and the joining through hole are arranged with a phase shift.   Carbon fiber reinforced resin is obtained by laminating carbon fiber prepregs in which carbon fibers are planarly oriented in one direction and impregnated with resin so as to intersect between adjacent carbon fiber prepregs, and the resin is cured. The vehicle axle bearing according to any one of claims 1 to 3, wherein the carbon fiber is oriented so as to be perpendicular to the bolt insertion hole.   The carbon fiber reinforced resin is obtained by laminating carbon fiber prepregs obtained by braiding carbon fibers in a flat shape and impregnating the resin, and heat-curing the resin, and the carbon fibers are in the bolt insertion holes. The vehicle axle bearing according to any one of claims 1 to 3, wherein the vehicle axle bearing is oriented so as to be vertical.   The vehicle axle bearing according to any one of claims 1 to 5, wherein the carbon fiber prepreg has a carbon fiber content of 10 to 80 mass%.   Carbon fiber has a tensile strength of 3 to 8.5 GPa, a tensile modulus of 220 to 700 GPa, and an elongation of 0.5 to 2.2%. Vehicle axle bearings.   The vehicle axle bearing according to any one of claims 1 to 7, wherein the resin used for 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 8, further comprising a sensor for detecting a rotation speed of the axle.

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