JP2013067323A - Bearing device for axle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for an axle capable of suppressing judder in a brake by suppressing degradation in flatness of a wheel mounting surface of a hub flange due to press-fitting of a hub bolt.SOLUTION: A bearing device 1 for an axle has a wheel mounting surface 13h to which a wheel 17 and a brake disk 19 are fixed at the wheel side end of a hub flange 13b. In the bearing device 1, an axially recessing thin portion 13i is formed between each adjacent bolt holes 13l in a circumferential direction on a side surface axially opposite to the wheel mounting surface 13h of the hub flange 13b to form radial thick portions 13k in the periphery of the plurality of bolt holes 13l. The axial thickness of the thin portion 13i is 1/3 or less of the axial thickness of the thick portion 13k; and the axially inner edge 13j of the recess defining the thin portion 13i is formed in an arch that has a center of curvature radially outside the midpoint of the centers of the adjacent bolt holes 13l, and a radially minimum position of the arc is located at the midpoint of the bolt holes 13l.

Description

  The present invention relates to an axle bearing device that supports wheels of an automobile or the like.

  In an axle bearing device to which an automobile wheel is mounted, for example, an inner ring member is rotatably supported via two rows of rolling elements inside an outer ring member fixed to the vehicle body side. A hub flange is formed on the shaft end side of the inner ring member, and a wheel and a brake disc are attached thereto.

  The hub flange is provided with a plurality of hub bolts for fixing wheels and brake disks to the hub flange at equal intervals in the circumferential direction. The hub bolt is attached by press-fitting into a bolt hole formed in the hub flange. By press-fitting the hub bolt, the periphery of the bolt hole on the wheel mounting surface of the hub flange is deformed, and the flatness of the wheel mounting surface is impaired. Due to this deterioration in flatness, vibration may occur during rotation, and this vibration may cause brake vibration called judder.

Further, the press-fitting of the hub bolt may cause the outer periphery of the hub flange to fall in the opposite direction to the wheel or brake disc, and the flatness of the wheel mounting surface may deteriorate. At this time, even after the hub bolt is tightened, the clearance between the brake disc remains on the outer peripheral portion of the wheel mounting surface, the vibration of the brake disc cannot be suppressed, and the judder is promoted.
In view of this, a structure has been proposed in which a groove that passes through in the axial direction is provided in the inner diameter of the bolt hole to reduce deformation such as bulging of the mounting surface and to reduce deterioration of flatness. (See Patent Document 1.)

JP 2008-137428 A

However, in the proposed structure, there is a possibility that the fixing force between the bolt hole and the hub bolt is insufficient, and a member such as a key is required for the countermeasure, which may cause a production problem. Further, in the proposed structure, the deterioration of the flatness of the wheel mounting surface due to the collapse of the hub flange cannot be suppressed.
An object of the present invention is to provide an axle bearing device that can reduce the occurrence of brake judder by suppressing deterioration in flatness of a wheel mounting surface of a hub flange caused by hub bolt press-fitting.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that an outer ring member and an inner ring member are disposed so as to be relatively rotatable around a shaft center via a rolling element, and the outer ring member or the inner ring A hub flange having a diameter increased radially outward is formed on one of the members, and a plurality of bolt holes for inserting a plurality of hub bolts are formed at predetermined positions of the hub flange. In a bearing device for an axle having a wheel mounting surface to which a wheel and a brake disk are fixed by inserting a hub bolt that is press-fitted into the bolt hole of a portion, a side surface opposite to the wheel side in the axial direction of the hub flange A thin-walled portion that is recessed in the axial direction in the middle of the plurality of bolt holes in the circumferential direction, a radial thick-walled portion is formed around the plurality of bolt holes, and the axial thickness of the thin-walled portion Said thick And the inner circumferential portion of the recess forming the thin portion has a center of curvature radially outward of the midpoint between the adjacent bolt holes, and has a diameter of The minimum position in the direction is formed in an arch shape equal to the midpoint of the bolt hole.

  Conventionally, it has been considered that the influence of the thickness of the thin-walled portion is small on the fluctuation of the wheel mounting surface caused by press-fitting the hub bolt into the bolt hole. However, as a result of various studies, the dimensional range of the present invention, that is, the axial thickness of the thin portion is 1/3 or less of the axial thickness of the thick portion, and the hollow circle forming the thin portion It has been found that if the circumferentially inner portion is formed in the arch shape, the deterioration of the flatness of the wheel mounting surface caused by the press-fitting of the hub bolt into the bolt hole is greatly improved as compared with the conventional product. This is because the thin-walled portion reduces the axial deformation of the wheel mounting surface around the thick-walled portion, and the thin-walled portion restricts the deformation of the adjacent thick-walled portion.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 2 is that a shaft between the plurality of bolt holes in the circumferential direction of the side surface of the hub flange opposite to the wheel mounting surface and the axial direction is provided. A thin-walled portion that is recessed in the direction is formed, a radial thick-walled portion is formed around the plurality of bolt holes, and a circumferential width on the PCD of the plurality of bolt-holes of the thick-walled portion is It is less than 2.5 times the inner diameter.

  Conventionally, it has been considered that the influence of the width in the circumferential direction of the thick wall portion is small against the deformation of the wheel mounting surface due to the press-fitting of the hub bolt into the bolt hole. However, as a result of various studies by the inventors, the dimension range of the present invention, that is, the circumferential width on the PCD of the plurality of bolt holes of the thick part is more than 2.5 times the inner diameter dimension of the bolt holes. In a small range, it has been found that the deterioration of the flatness of the wheel mounting surface due to the press-fitting of the hub bolt into the bolt hole is greatly reduced. This is because when the circumferential width of the thick wall portion is smaller than 2.5 times the inner diameter of the bolt hole, the expansion amount around the bolt hole due to the press-fitting of the hub bolt into the bolt hole is That is, it is larger in the circumferential direction, that is, in the thin portion direction than in the wheel mounting surface direction.

  In order to solve the above-described problem, the structural feature of the invention according to claim 3 is that a bolt press-fit portion having a smaller diameter than other portions of the inner diameter portion is formed in a part of the inner diameter portion of the plurality of bolt holes in the axial direction. Formed, the axial center of the bolt press-fit portion is biased toward the wheel mounting surface side from the axial center of the hub flange, and is the position where the runout of the wheel mounting surface due to hub bolt press-in is the smallest in calculation, The surface is a concave surface that is radially inward from the wheel and the brake disc in a state before press-fitting the hub bolt, and a concave inclination angle radially outward from the bolt hole PCD is inward from the bolt hole PCD. This is larger than the concave inclination angle.

  According to the axle bearing device of the present invention, the circumferential deformation of the wheel mounting surface caused by press-fitting the hub bolt into the bolt hole is minimized as compared with other press-fitting positions. Further, as a result of various studies by the present inventor, the wheel mounting surface of the hub flange falls in the direction in which the outer diameter side moves away from the wheel due to press-fitting of the hub bolt into the bolt hole, and the fall is outside the PCD of the bolt hole. It has been found that is larger than the inside of the bolt hole PCD. According to the axle bearing device of the present invention, the wheel mounting surface of the hub flange having a concave shape before press-fitting is deformed in a direction for correcting the concave shape by press-fitting the hub bolt into the hub flange. For this reason, the deterioration of the flatness of the wheel mounting surface due to the press-fitting of the hub bolt into the bolt hole is greatly improved.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 4 is that the outer ring member and the inner ring member are arranged so as to be relatively rotatable around the axis through the rolling elements, and the outer ring member or the inner ring One of the members is formed with a hub flange whose diameter is increased radially outward, and a plurality of bolt holes for press-fitting a plurality of hub bolts are formed at predetermined positions of the hub flange. In a bearing device for an axle having a wheel mounting surface in which a hub bolt inserted by press-fitting into the bolt hole is inserted into a part and a wheel and a brake disk are fixed, a part of the inner diameter part of the plurality of bolt holes in the axial direction A bolt press-fit portion having a smaller diameter than other parts of the inner diameter portion is formed, and the axial center of the bolt press-fit portion is biased toward the wheel mounting surface side from the axial center of the hub flange. The wheel mounting surface is a position where the runout of the wheel mounting surface due to the bolt press-in is reduced, and the wheel mounting surface is a concave surface that is radially inwardly separated from the wheel and the brake disc in the state before the hub bolt press-fitting, and the bolt hole The concave inclination angle radially outward from the PCD is larger than the concave inclination angle inward from the bolt hole PCD.

  According to the axle bearing device of the present invention, the circumferential deformation of the wheel mounting surface caused by press-fitting the hub bolt into the bolt hole is minimized as compared with other press-fitting positions. Further, as a result of various studies by the present inventor, the wheel mounting surface of the hub flange falls in the direction in which the outer diameter side moves away from the wheel due to press-fitting of the hub bolt into the bolt hole, and the fall is outside the PCD of the bolt hole. It has been found that is larger than the inside of the bolt hole PCD. According to the axle bearing device of the present invention, the wheel mounting surface of the hub flange that is concave before press-fitting is deformed in a direction to correct the concave shape by press-fitting the hub bolt into the hub flange, and the flatness Deterioration of is greatly improved.

  ADVANTAGE OF THE INVENTION According to this invention, the axle bearing apparatus which can suppress the judder generation | occurrence | production of a brake by suppressing the deterioration of the flatness of the wheel mounting surface of a hub flange by hub bolt press injection can be provided.

It is sectional drawing of the axial direction of the bearing apparatus for axles of the 1st Embodiment of this invention. It is a top view of the hub flange of the bearing device for axles of a 1st embodiment of the present invention. It is explanatory drawing explaining the effect of the bearing apparatus for axles of the 1st Embodiment of this invention. It is explanatory drawing explaining the effect of the bearing apparatus for axles of the 1st Embodiment of this invention. It is sectional drawing of the axial direction of the axle bearing apparatus of the 2nd Embodiment of this invention. It is an enlarged view of the bolt hole of the hub flange of the axle bearing device of the 2nd Embodiment of this invention. It is a virtual sectional view of hub flange 23b of an axle bearing device of a 2nd embodiment of the present invention. It is explanatory drawing explaining an effect | action and effect of the axle bearing apparatus of the 2nd Embodiment of this invention. It is explanatory drawing explaining an effect | action and effect of the axle bearing apparatus of the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, FIG. 5, FIG. 6, FIG. 7, the left side shows the inboard side, and the right side shows the outboard side.

(First embodiment)
FIG. 1 is an axial sectional view of an axle bearing device according to a first embodiment of the present invention.
1 includes an outer ring 11 as an outer ring member, a hub shaft 13 as an inner ring member, an inner ring 12 as an inner ring member, a plurality of balls 14 as rolling elements, and two cages. 15 and a plurality of hub bolts.

  The outer ring 11 is annular and has a radially outwardly expanding diameter at the inboard side end portion, and has a fixing flange 11c for mounting the axle bearing device 1 to the vehicle body 18, and the fixing flange 11c has a fixing bolt 18a. A plurality of through-holes 11d are provided. An inboard side outer ring raceway 11a is formed on the inner peripheral part of the outer ring 11 on the inboard side, and an outboard side outer ring raceway 11b is formed on the inner peripheral part on the outboard side.

  The hub shaft 13 has an outboard side inner ring raceway 13a on the outer peripheral portion at the center in the axial direction, and a hub flange 13b that expands radially outward on the outer peripheral surface of the end portion on the outboard side. The end surface on the outboard side of the hub flange 13b is a wheel mounting surface 13h to which the wheel 17 and the brake disc 19 are mounted. The hub flange 13b is formed with a plurality of bolt holes 13l penetrating at predetermined positions at equal intervals on the circumference. Bolt press-fitting portions 13m having a smaller diameter than both end portions are provided in the inner diameter portions of the plurality of bolt holes 13l.

  A hub shaft outer diameter surface 13e is formed on the outer surface of the hub shaft 13 from the outboard side inner ring raceway 13a to the inboard side. Inner ring fitting portion side surface 13f that radially decreases from the end on the inboard side of hub shaft outer diameter surface 13e, and inner ring fitting portion that extends from inner diameter corner portion 13g of inner ring fitting portion side surface 13f to the inboard side. 13c is formed.

  The inner ring 12 is annular, and an inboard side inner ring raceway 12a is formed on the outer peripheral part in the axial center, a large outer diameter part 12c is formed on the outer peripheral part on the inboard side, and a small outer diameter part 12d is formed on the outer peripheral part on the outboard side. It has an inner diameter surface 12b concentric with the inner ring raceway 12a on the periphery. Further, a small end surface 12e extends inward in the diameter direction from the end portion on the outboard side of the small outer diameter portion 12d. Furthermore, a large end surface 12f extends from the end on the inboard side of the large outer diameter portion 12c toward the inner diameter surface 12b inward in the diameter direction.

  The inner ring 12 is externally fitted to the inner ring fitting portion 13 c of the hub shaft 13 with the small end surface 12 e abutting against the fitting portion side surface 13 f of the hub shaft 13. Further, the end portion of the hub shaft 13 is formed with a caulking portion 13d that prevents the inner ring 12 from coming off by bending and deforming the cylindrical end portion radially outward and pressing the large end surface 12f of the inner ring 12.

  The balls 14 as a plurality of rolling elements in two rows are respectively held by the cage 15 at a predetermined interval in the circumferential direction, and the inboard side outer ring raceway 11a of the outer ring 11 and the inboard side inner ring raceway 12a of the inner ring 12 are arranged. And between the outboard side outer ring raceway 11b of the outer ring 11 and the outboard side inner ring raceway 13a of the hub axle 13.

  The plurality of hub bolts 16 have a disc-shaped bolt head 16a at the end of the inboard side, and a serration 16b having an interference with the press-fit portion 13m of the bolt hole 13l of the hub flange 13b from the base portion of the bolt head 16a to the outboard side. Is formed. A threaded portion 16c for screwing the hub nut 17a and fixing the wheel 17 and the brake disc 19 to the wheel mounting surface 13h is formed at the end portion on the outboard side. In the plurality of hub bolts 16, serrations 16b are press-fitted into press-fitting portions 23m of bolt holes 23l of the hub flange 23b, and are fitted into bolt holes 13l of the hub flange 13b.

  FIG. 2 is a plan view of the hub flange 13b of the axle bearing device 1 according to the first embodiment of the present invention viewed from the inboard side. An inboard side end face of the hub flange 13b is formed with a thin portion 13i that is recessed in the axial direction between the plurality of bolt holes 13l in the circumferential direction, and a radially thick portion 13k is formed around the plurality of bolt holes. The circumferential width B of the thick portion 13k on the bolt PCD is not more than 2.5 times the diameter d of the bolt hole 13l, and the axial thickness of the thin portion 13i is the axial thickness of the thick portion 13k. The inner radial edge 13j of the recess forming the thin portion 13i has a center of curvature radially outward at the midpoint of the adjacent bolt hole 13l, and is the smallest in the radial direction. The position is formed in an arch shape having a radius of curvature R equal to the midpoint of the bolt hole 13l.

  FIG. 3 is an explanatory diagram for explaining the operation of the axle bearing device. The graph of FIG. 3 shows the result of the relationship between the width of the thick part of the hub flange and the runout of the wheel mounting surface obtained by FEM when the hub bolt is press-fitted into the bolt hole. From this graph, it can be seen that if the width of the thick portion of the hub flange is less than 36 mm, the runout of the mounting surface will rapidly decrease. The bolt hole diameter at this time is 14.4 mm, and the width of the thick part of the hub flange is 36 mm, which is 2.5 times the bolt hole diameter.

  The width B of the thick portion 13k of the hub flange 13b of the axle bearing device 1 of the first embodiment is formed to be 2.5 times or less the diameter d of the bolt hole 13l. For example, if the width B of the thick portion 13k of the hub flange 13b is twice the diameter d of the bolt hole 13l, this corresponds to the width of 28.8 mm of the thick portion of the hub flange in FIG. The runout of the wheel mounting surface at this time is about 0.025 mm, and the runout of the wheel mounting surface 13 h when the width of the thick part of the hub flange is 36 mm, that is, 2.5 times the bolt hole diameter or more is about 0.032 mm. It can be seen that it is reduced by about 25%.

  FIG. 4 is an explanatory view for explaining the operation of the axle bearing device. The graph of FIG. 4 shows the result of FEM determining the relationship between the circumferential position of the outer periphery of the hub flange and the axial displacement of the wheel mounting surface when a hub bolt is press-fitted into the bolt hole. A dotted line indicates a conventional product, and a solid line indicates a shape product of the present invention. The scale on the horizontal axis represents the position in the circumferential direction as an angle, and 36 ° corresponds to an intermediate position between adjacent bolt holes.

  In the graph of FIG. 4, in the case of the conventional product, the bolt hole position is displaced by about 0.005 mm toward the inner side, and the displacement at the intermediate position between adjacent bolt holes is 0.035 mm at the maximum. That is, when the hub flange rotates, the runout of the wheel mounting surface becomes 0.040 mm.

  In the case of the axle bearing device 1 of the first embodiment, the bolt hole position is displaced about 0.001 mm toward the inner side, and the intermediate position between adjacent bolt holes is displaced 0.030 mm toward the outer side. The maximum displacement is a displacement in the outer direction of 0.032 mm at a position of about 22 ° from the bolt hole. From the above, it can be seen that the runout of the wheel mounting surface 13h in the axle bearing device 1 of the first embodiment is 0.033 mm, which is about 18% less than the conventional product. That is, the product of the present invention can suppress the occurrence of brake judder by suppressing the deterioration of the flatness of the wheel mounting surface of the hub flange due to the hub bolt press-fitting.

(Second Embodiment)
FIG. 5 is a sectional view in the axial direction of the axle bearing device 20 according to the second embodiment of the present invention.
The axle bearing device 20 of the second embodiment is different from the first embodiment in the shape and configuration of the hub axle.
In the axle bearing device 20 of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted. Further, the description of the configuration and the effect common to those of the first embodiment will be omitted, and only the configuration and the effect different from the axle bearing device of the first embodiment will be described.

  The hub shaft 23 has an outboard side inner ring raceway 23a on the outer peripheral portion at the center in the axial direction, and a hub flange 23b that expands radially outward on the outer peripheral surface of the end portion on the outboard side. The end surface on the outboard side of the hub flange 23b is a wheel mounting surface 23h to which the wheel 17 and the brake disc 19 are mounted. A plurality of bolt holes 23l are formed through the hub flange 23b at predetermined positions at equal intervals on the circumference. The inner diameter portion of the bolt hole 23l has a bolt press-fit portion 23m having a smaller diameter than both ends.

  A hub shaft outer diameter surface 23e is formed on the outer surface on the inboard side from the outboard side inner ring raceway 23a of the hub shaft 23. Inner ring fitting portion side surface 23f radially reducing from the end portion on the inboard side of hub shaft outer diameter surface 23e, and inner ring fitting portion extending from the inner diameter corner portion 23g of inner ring fitting portion side surface 23f to the inboard side. 23c is formed.

  The inner ring 12 is externally fitted to the inner ring fitting portion 23c of the hub shaft 23 with the small end surface 12e coming into contact with the fitting portion side surface 23f of the hub shaft 23. Further, the end portion of the hub shaft 23 is formed with a caulking portion 23d that prevents the inner ring 12 from coming off by bending and deforming the cylindrical end portion outward in the diametrical direction and pressing it against the large end surface 12f of the inner ring 12.

  The balls 14 as a plurality of rolling elements in two rows are respectively held by the cage 15 at a predetermined interval in the circumferential direction, and the inboard side outer ring raceway 11a of the outer ring 11 and the inboard side inner ring raceway 12a of the inner ring 12 are arranged. And between the outboard side outer ring raceway 11b of the outer ring 11 and the outboard side inner ring raceway 23a of the hub axle 23.

  The plurality of hub bolts 16 have a disc-shaped bolt head 16a at the end of the inboard side, and a serration 16b having an interference with the press-fit portion 13m of the bolt hole 13l of the hub flange 13b from the base portion of the bolt head 16a to the outboard side. Is formed. A threaded portion 16c for screwing the hub nut 17a and fixing the wheel 17 and the brake disc 19 to the wheel mounting surface 23h of the hub flange 23b is formed at the end portion on the outboard side. In the plurality of hub bolts 16, serrations 16b are press-fitted into press-fitting portions 23m of bolt holes 23l of the hub flange 23b, and are fitted into the bolt holes 23l of the hub flange 23b.

FIG. 6 is an enlarged cross-sectional view of the bolt hole 23l of the hub flange 23b of the axle bearing device 20 according to the second embodiment of the present invention. A bolt press-fit portion having a smaller diameter than both ends is provided in the inner diameter portion of the bolt hole 23l. The axial center position CLm of the bolt press-fit portion 23m is biased by Δ from the axial center position CLb of the hub flange 23 toward the outboard side.

FIG. 7 is a virtual cross-sectional view of the hub flange 23b of the axle bearing device 20 according to the second embodiment of the present invention. In FIG. 6, for easy explanation, the angle of the hub flange with respect to the axis center is exaggerated, and portions that do not directly affect the operation are omitted.
The wheel mounting surface 23h of the hub flange 23b before the hub bolt 16 is inserted is inclined outwardly at an angle α1 from the wheel mounting surface root 23n to the PCD of the bolt hole 23l radially outward, and from the PCD of the bolt hole 23l. The radially outer side is formed as a concave surface inclined to the outer side at an angle α2.

FIG. 8 is an explanatory view for explaining the operation of the axle bearing device. The graph of FIG. 8 shows the relationship between the axial press-fitting position when the hub bolt is fitted into the bolt hole and the deflection of the wheel mounting surface, and the axial press-fitting position and the tilt of the wheel mounting surface. The tilt of the wheel mounting surface is the average value of all the circumferences in the axial distance between the root of the wheel mounting surface and the outermost periphery of the wheel mounting surface, and the runout of the wheel mounting surface is in the circumferential direction of the entire wheel mounting surface. It is the maximum value of the unevenness in the axial direction.
In the graph, the wheel mounting surface collapse and the wheel mounting surface deflection at each distance are values obtained by FEM.

The horizontal axis is the distance from the axial center position of the press-fit portion formed in the bolt hole to the axial center position of the hub flange, the right direction is the inner side and the left direction is the outer side.
In the vertical axis, the right scale is the tilt of the wheel mounting surface corresponding to the line graph, the upper direction is the inner side, and the lower direction is the outer side. The left scale is the runout of the wheel mounting surface corresponding to the bar graph.

From FIG. 8, it can be seen that when the distance from the axial center position of the press-fit portion to the axial center position of the hub flange is 1.5 mm on the outer side, the runout of the wheel mounting surface is minimized. From the above examination results, the deviation Δ of the axial center position CLm of the press-fit portion 23m of the bolt hole 23l of the axle bearing device 20 of the second embodiment of the present invention in FIG. 6 with respect to the axial center position CLb of the hub flange 23b is Δ. Is 1.5 mm on the outer side where the runout of the wheel mounting surface 13h is minimized.
Further, it can be seen from FIG. 8 that the tilting of the wheel mounting surface 23h when the hub bolt 16 is fitted into the bolt hole 23l of the axle bearing device 20 is about 0.1 mm on the inner side.

  FIG. 9 is an explanatory view for explaining the operation of the axle bearing device 20 according to the second embodiment of the present invention. The graph of FIG. 9 shows the axial shape of the wheel mounting surface 23h and the axial displacement of the wheel mounting surface 23h when the hub bolt 16 is fitted into the bolt hole 23l. The horizontal axis indicates the distance in the radial direction from the base of the wheel mounting surface 23h to the outermost periphery.

  Line A is an average value of the entire circumference of the axial displacement amount of the wheel mounting surface 23h at each radial position when the hub bolt 16 is inserted into the bolt hole 23l obtained by the FEM described above. It can be seen that the wheel mounting surface 23h has a smaller displacement inward than the bolt hole position in the radial direction, and the outer side is larger than the bolt hole position, and a collapse that deforms toward the inner side occurs.

  Line B is the shape of the wheel mounting surface 23h of the axle bearing device 20 before the bolt 16 is inserted, which is determined based on the amount of axial displacement of the wheel mounting surface 23h at each radial position described above. From the root of the wheel mounting surface to the outer side in the radial direction to the bolt hole, the outer side is inclined at an angle α1, and the outer side in the radial direction from the bolt hole is formed as a concave surface inclined at the outer side at an angle α2. α1 is 0.1 ° to 0.2 °, and α2 is about 3 times α1 and is 0.3 ° to 0.6 °.

  Line C is the shape of the wheel mounting surface 23h of the axle bearing device 20 after the hub bolt 16 is fitted in each radial position described above, and the outermost peripheral portion is inclined to the outer side by about 0.05 mm. . As shown in FIG. 5, when the inserted hub bolt 16 is inserted and the hub nut 17a is tightened and the brake disc 19 and the wheel 17 are fixed to the wheel mounting surface 23h, the wheel mounting surface 23h and the brake disc 19 are fully exposed. It has been found that it is the best shape that can adhere to the surface.

  That is, the axle bearing device 20 according to the second embodiment of the present invention suppresses the deterioration of the flatness of the wheel mounting surface of the hub flange due to the hub bolt insertion, and further, the wheel of the hub flange after the wheel and the brake disk are fixed. By eliminating the clearance between the mounting surface and the brake disc, the occurrence of brake judder can be suppressed.

(Other embodiments)
The axle bearing device according to the first embodiment and the second embodiment is configured such that the rolling element is constituted by a ball, but in the present invention, the rolling element is an axle bearing device constituted by a roller such as a tapered roller. There may be.

  The axle bearing device in the first embodiment and the second embodiment is an axle bearing device for a driven wheel, but may be an axle bearing device for a drive wheel in the present invention.

  The axle bearing device in the first and second embodiments is an axle bearing device in which the hub shaft is integrated with one inner ring. However, in the present invention, the hub shaft and the inner ring are separate axle bearings. It may be a device.

  The axle bearing device in the first and second embodiments is an axle bearing device in which the hub shaft is integrated with one inner ring. However, in the present invention, the hub shaft and the inner ring are separate axle bearings. It may be a device.

  In the present invention, the axle bearing device may be an axle bearing device having the characteristics of both the first embodiment and the second embodiment.

1, 20 ... Axle bearing device 11 ... Outer ring (outer ring member)
12 ... Inner ring (inner ring member)
13, 23 ... Hub axle (inner ring member)
13b, 23b · Hub flange 13h, 23h · Wheel mounting surface 13i · Thin wall portion 13j · Inner edge portion 13k · Thick wall portion 13l and 23l · Bolt holes 13m and 23m · Press fit portion 14 · Ball (rolling element)
16 ... Hub bolt 17 ... Wheel 19 ... Brake disc

Claims (4)

The outer ring member and the inner ring member are disposed so as to be relatively rotatable around a shaft center via a rolling element, and a hub flange having a radially increased diameter is formed on one of the outer ring member and the inner ring member. A plurality of bolt holes for inserting a plurality of hub bolts are formed at predetermined positions of the flange, and a hub bolt inserted into the bolt hole by press-fitting into the wheel side end portion of the hub flange is inserted into the wheel and the brake disc. In an axle bearing device having a wheel mounting surface to which is fixed,
A thin-walled portion recessed in the axial direction is formed between the plurality of bolt holes in a circumferential direction on a side surface opposite to the wheel mounting surface of the hub flange, and a radial thickness is formed around the plurality of bolt holes. A thin portion is formed, an axial thickness of the thin portion is formed to be 1/3 or less of an axial thickness of the thick portion, and a radially inner edge of the recess forming the thin portion is An axle bearing device having a center of curvature radially outward of an intermediate point between adjacent bolt holes and having an arcuate shape having a minimum radial position equal to the intermediate point of the bolt hole.   2. The axle bearing device according to claim 1, wherein a circumferential width of the thick portion on the PCD of the plurality of bolt holes is smaller than 2.5 times an inner diameter dimension of the bolt holes. A bolt press-fit portion having a smaller diameter than other portions is formed in a part of the inner diameter portion of the plurality of bolt holes in the axial direction, and the axial center of the bolt press-fit portion is closer to the wheel mounting surface than the axial center of the hub flange. It is a position where the runout of the wheel mounting surface due to hub bolt press-in is the smallest in the calculation,
The wheel mounting surface is a concave surface that is radially inwardly separated from the wheel and the brake disc in a state before the hub bolt press-fitting, and a concave slope angle radially outward from the bolt hole PCD is the bolt hole PCD. 3. Axle bearing device according to claim 1 or 2, characterized in that it is larger than the inward concave inclination angle. The outer ring member and the inner ring member are disposed so as to be relatively rotatable around a shaft center via a rolling element, and a hub flange having a radially increased diameter is formed on one of the outer ring member and the inner ring member. A plurality of bolt holes for press-fitting a plurality of hub bolts at predetermined positions of the flange are formed, and a hub bolt inserted into the bolt hole by press-fitting is inserted into a wheel side end portion of the hub flange so that the wheel and the brake disc are inserted. In an axle bearing device having a wheel mounting surface on which
A bolt press-fit portion having a smaller diameter than other portions is formed in a part of the inner diameter portion of the plurality of bolt holes in the axial direction, and the axial center of the bolt press-fit portion is closer to the wheel mounting surface than the axial center of the hub flange. It is a position where the runout of the wheel mounting surface due to hub bolt press-in is the smallest in the calculation,
The wheel mounting surface is a concave surface that is radially inwardly separated from the wheel and the brake disc in a state before the hub bolt press-fitting, and a concave slope angle radially outward from the bolt hole PCD is the bolt hole PCD. A bearing device for an axle characterized by being larger than the inward concave inclination angle.

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