JP2011133067A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which reduces the weight of an outer member, and suppresses the vibration of the outer member accompanying the rolling of a rolling element. <P>SOLUTION: The bearing device 1 for the wheel includes an inner member 2 having an inner raceway surface 60a formed on an outer periphery and a wheel attachment surface 61d to which the wheel is attached, the outer member 3 arranged around the outer periphery of the inner member 2 and having an outer raceway surface 3a formed on an inner periphery and a connection surface 30d connected to a vehicle body side, and the plurality of rolling elements 4 arranged between the inner raceway surface 60a and the outer raceway surface 3a. In the outer member 3, a plurality of recesses having a circumferential opening width set to a dimension smaller than the circumferential pitch of a contact point in which the plurality of rolling elements 4 come into contact with the outer raceway surface 3a are formed on the outer peripheral surface on the wheel attachment surface 61d side of the inner member 2 compared with the connection surface 30d. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wheel bearing device, and more particularly to a wheel bearing device that rotatably supports a wheel of an automobile or the like with respect to a suspension device.

  As a conventional wheel bearing device, an inner member rotatable around a central axis, an outer member arranged around the inner member, and interposed between the outer member and the inner member There are some provided with a plurality of rolling elements (for example, Patent Document 1).

  The inner member includes a hub shaft and an inner ring, and is disposed rotatably on the central axis. The hub shaft has a wheel mounting flange on the outer peripheral surface, is connected to a constant velocity universal joint so as to be able to transmit torque, and is nut-fastened. Wheels are attached to the hub axle via wheel attachment flanges. The inner ring is attached to the end of the hub shaft on the vehicle body side.

  The outer member has a vehicle body mounting flange on the outer peripheral surface, and is attached to the vehicle body side via a knuckle of a suspension device. The outer member is formed with a plurality of cut portions (concave portions) arranged in parallel along the circumferential direction on the outer peripheral surface thereof for weight reduction.

  The plurality of rolling elements are made of steel balls, are arranged in two rows parallel to each other along the central axis, and are held by a cage along the circumferential direction of each row so as to be able to roll. Of these, the rolling elements in the wheel side row are between the inner peripheral surface of the outer member and the outer peripheral surface of the hub shaft, and the rolling members in the vehicle body side row are between the inner peripheral surface of the outer member and the outer peripheral surface of the inner ring. They are arranged between each other.

  With the above configuration, when torque is transmitted from the engine side of the vehicle to the hub shaft via a constant velocity universal joint or the like, the hub shaft rotates together with the inner ring. Since the wheel is attached to the hub axle, torque from the engine side is also transmitted to the wheel, and the wheel rotates together with the hub axle.

JP 2009-150490 A

  However, according to the wheel bearing device shown in Patent Document 1, since the two adjacent rolling elements of the plurality of rolling elements in the wheel side row are arranged in the region inside the same recess, the use is unexpected. Under the conditions, the outer member may vibrate as the rolling element rolls.

  This is because the thickness dimension of the outer member is different between the part where the concave part is formed and the part other than the part where the concave part is formed, and the rigidity of these parts is also different from each other. It is considered that the amount of deformation of the outer member changes due to the change in the relative positional relationship with the moving body, resulting in the generation of vibration.

  Accordingly, an object of the present invention is to provide a wheel bearing device capable of suppressing vibration of an outer member accompanying rolling of a rolling element.

  To achieve the above object, the present invention provides an inner member having an inner raceway surface formed on the outer periphery and a wheel mounting surface to which a wheel is attached, and an outer periphery of the inner member. An outer member having a formed outer raceway surface and a connecting surface coupled to the vehicle body side, and a plurality of rolling elements disposed between the inner raceway surface and the outer raceway surface, The direction member is set to a size smaller than the circumferential pitch of the contact point where the plurality of rolling elements are in contact with the outer raceway surface on the outer peripheral surface of the inner member on the wheel mounting surface side than the connection surface. Provided is a wheel bearing device in which a plurality of recesses having a circumferential opening width are formed.

  According to the present invention, the vibration of the outer member accompanying the rolling of the rolling elements can be suppressed.

Sectional drawing shown in order to demonstrate the whole wheel bearing apparatus which concerns on embodiment of this invention. The front view shown in order to demonstrate the formation position of the recessed part of the outer member in the wheel bearing apparatus which concerns on embodiment of this invention. (A) And (b) is the perspective view and sectional drawing shown in order to demonstrate the recessed part of the outward member in the bearing apparatus for wheels which concerns on embodiment of this invention. (A) is a perspective view, and (b) is a cross-sectional view. The top view shown in order to demonstrate the recessed part of the outward member in the wheel bearing apparatus which concerns on embodiment of this invention. The perspective view shown in order to demonstrate the modification (1) of the recessed part of the outer member in the wheel bearing apparatus which concerns on embodiment of this invention. The front view shown in order to demonstrate the modification (2) of the recessed part of the outer member in the wheel bearing apparatus which concerns on embodiment of this invention.

[Embodiment]
(Whole configuration of wheel bearing device)
FIG. 1 is an axial cross-sectional view showing the entire wheel bearing device. The wheel bearing device 1 includes an inner member 2 that can rotate around a central axis O, an outer member 3 that is disposed on the outer periphery of the inner member 2, and the outer member 3 and the inner member. 2 are provided between the vehicle body (not shown) and the wheels (not shown).

(Configuration of the inner member 2)
The inner member 2 includes a hub shaft 6 and an inner ring 7 and is disposed on the central axis O so as to be rotatable.

  The hub shaft 6 has a large-diameter barrel portion 6a and a small-diameter barrel portion 6b having different outer diameters. The hub shaft 6 is connected to a constant velocity universal joint (not shown) so as to be able to transmit torque and is fastened with a nut. The whole is formed of a cylindrical shaped body made of a metal such as medium carbon steel. The hub axle 6 is provided with a through hole 6c that opens in both directions along the central axis O. A serration 60c for connecting a stem (not shown) of a constant velocity universal joint is formed on the inner peripheral portion of the through hole 6c.

  The large-diameter trunk portion 6a is an inner side that rolls the plurality of rolling elements 4 in the first row arranged on the wheel side (left side in FIG. 1) among the plurality of rolling elements 4 and 5 arranged in double rows. A raceway surface 60a is provided on the outer periphery. The large-diameter trunk portion 6a is integrally provided with an annular wheel mounting flange 6d that protrudes to the outer peripheral side and has a wheel mounting surface 61d for mounting a wheel (not shown). The wheel mounting flange 6d is provided with a plurality of (for example, four) bolt insertion holes 60d (only two are shown) through which the hub bolts 8 are inserted in parallel in the circumferential direction.

  The small-diameter trunk portion 6 b has an attachment surface 60 b for attaching the inner ring 7 on the outer peripheral surface, and is disposed on the vehicle body side (right side in FIG. 1) than the large-diameter trunk portion 6 a of the hub axle 6.

  On the other hand, the inner ring 7 has an inner raceway surface 7a for rolling the second row rolling elements 5 on the vehicle body side among the plurality of rolling elements 4 and 5 arranged in a double row on the outer peripheral surface, and has a small diameter barrel. It is fixed to the mounting surface 60b of the part 6b, and the whole is formed of a cylindrical molded body made of bearing steel such as SUJ2, for example.

(Configuration of the outer member 3)
The outer member 3 has outer raceway surfaces 3a and 3b for rolling the plurality of rolling elements 4 and 5 in the first and second rows on the inner periphery, and connecting surfaces 3c and 30d connected to the vehicle body side. At one end in the axial direction. Further, the outer member 3 has a connecting surface 3c, 30d fixed to the vehicle body side via a knuckle 9 as a component of a suspension device (not shown), and opens in both directions of the central axis O, for example, bearing steel such as SUJ2. It is formed by the cylindrical molded object which consists of.

  The outer member 3 is integrally provided with an annular vehicle body mounting flange 3d that protrudes radially outward from an outer peripheral surface 30a including a portion corresponding to the outer periphery of the outer raceway surface 3a. A connecting surface 30d is formed on one side surface of the vehicle body mounting flange 3d facing the knuckle 9, and a cylindrical connecting surface 3c is formed so as to extend in a direction orthogonal to the connecting surface 30d. The vehicle body mounting flange 3d is provided with a plurality of (for example, four) bolt insertion holes (not shown) that are arranged in parallel in the circumferential direction and through which knuckle bolts (not shown) are inserted.

(Configuration of double row rolling elements 4 and 5)
The plurality of rolling elements 4 in the first row are made of steel balls, are disposed between the inner raceway surface 60a of the hub shaft 6 and the outer raceway surface 3a of the outer member 3, and are caged (not shown). )) So that it can roll. A wheel-side seal member 10 interposed between the outer peripheral surface of the hub shaft 6 and the inner peripheral surface of the outer member 3 is disposed on the wheel side of the rolling element 4. In the first row, for example, ten rolling elements 4 are arranged at equal intervals along the circumferential direction of the central axis O.

  The second row of rolling elements 5 is made of steel balls, and is disposed between the inner raceway surface 7a of the inner ring 7 and the outer raceway surface 3b of the outer member 3, and by a cage (not shown). It is held so that it can roll. On the vehicle body side of the rolling element 5, a vehicle body side seal member 11 interposed between the outer peripheral surface of the inner ring 7 and the inner peripheral surface of the outer member 3 is disposed. In the second row, the same number of rolling elements 5 as the rolling elements 4 in the first row are arranged at regular intervals along the circumferential direction of the central axis O.

  FIG. 2 shows the external appearance of the outer member 3. The outer member 3 is on the outer peripheral side, and is on the side where the wheel mounting surface 61d (see FIG. 1) of the inner member 2 is formed with respect to portions excluding the connecting surfaces 3c and 30d, that is, the connecting surfaces 3c and 30d. A plurality of recesses 3e are formed on the outer peripheral surface 30a. The recess 3e is also formed on the outer peripheral flange surface 31d of the vehicle body mounting flange 3d and the wheel side flange end surface 32d on the side surface opposite to the connecting surface 30d of the vehicle body mounting flange 3d. Between the two recessed parts 3e and 3e adjacent to each other among the plurality of recessed parts 3e, a ridge 3f thicker than the recessed part 3e is provided. The protrusion 3f formed on the outer peripheral surface 30a is formed to extend in a direction parallel to the central axis O and a direction inclined with respect to the circumferential direction.

Fig.3 (a) is a perspective view which shows the shape of the some recessed part 3e. The plurality of recesses 3e are formed in a square shape, and are provided adjacent to each other via a plurality of protrusions 3f formed in a lattice shape between the recesses 3e. Circumferential opening width of the recess 3e in (vertical direction in FIG. 3 (a)) of the outer member is set to P _1.

FIG. 3B shows the outer member 3 and the hub shaft 6 of the inner member 2 in a cross section orthogonal to the central axis O, and a plurality of rolling elements 4 arranged between these members. Circumferential opening widths of the plurality of recesses 3e _{P 1} is smaller than the circumferential pitch _{P 2} between the contact points _O 1, _{O 2} with the outer raceway surface 3a of the rolling elements 4 of the wheel-side rows _(P 1 _{<P 2} ) The dimensions are set. More specifically, the size of the circumferential opening width P _1, less than one dimension of half of the circumferential pitch P _2, further than one dimension of the third circumferential pitch P ₂ Is also small.

Further, the circumferential angle of the circumferential opening width of the recess 3e with respect to the central axis O is smaller than the size of one half of the angle between the circumferential contacts O ₁ and O _{2 with} respect to the central axis O. And even smaller than one-third of the size. In the present embodiment, the circumferential angle with respect to the central axis O of the circumferential opening width of the recess 3e is 8 °, and the circumferential angle with respect to the central axis O between the contacts O ₁ and O _{2 in the} circumferential direction. Is set to 36 °.

  FIG. 4 shows in detail the shape of the plurality of recesses 3e formed on the outer peripheral surface 30a, and the vertical direction in the figure corresponds to the circumferential direction. In the plurality of recesses 3e, circumferential corners 30e are formed by curved surfaces by R chamfering so as to suppress the occurrence of damage due to stress concentration.

(Manufacturing method of the outer member 3)
The formation of the plurality of recesses 3e is performed while leaving the forged surface when the outer member 3 is formed by forging. That is, a forging die for molding the outer member 3 formed with a shape corresponding to the shape of the recess 3e is pressed against the outer peripheral surface of the material to be the outer member 3 to apply pressure. The recess 3e is molded simultaneously with the molding of the entire shape of the member 3.

  The plurality of protrusions 3f are formed so as to constitute a lattice-shaped molded body. The outer peripheral surface of the protrusion 3f may be subjected to cutting after forging. The connecting surfaces 3c and 30d (shown in FIG. 2) are subjected to cutting after forging.

(Operation of the wheel bearing device 1)
The operation of the wheel bearing device 1 shown in the present embodiment is performed similarly to the operation of the conventional wheel bearing device. That is, when torque is transmitted from the engine side of the vehicle to the hub shaft 6 through a constant velocity universal joint or the like, the hub shaft 6 rotates together with the inner ring 7. Since the wheel is attached to the hub shaft 6, torque from the engine side is also transmitted to the wheel, and the wheel rotates together with the hub shaft 6. At this time, the plurality of rolling elements 4 in the first row are on the outer raceway surface 3 a of the outer member 3 and the inner raceway surface 60 a of the inner member 2, and the plurality of rolling elements 5 in the second row are on the outer side of the outer member 3. The raceway surface 3b and the inner raceway surface 7a of the inner ring 7 are rolled.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) Since the plurality of recesses 3e are formed on the outer peripheral surface 30a of the outer member 3, the flange peripheral surface 31d on the outer periphery of the vehicle body mounting flange 3d, and the wheel side flange end surface 32d, the recess 3e is not formed (protrusion). Compared to the case where the outer member 3 is formed with the thickness of the portion where the strip 3f is formed), the amount of forging material input can be reduced and the weight can be reduced. Moreover, since the protrusion 3f is formed compared with the case where the outer member 3 is formed with the thickness of the part in which the recessed part 3e was formed, intensity | strength becomes high. That is, according to the present embodiment, the strength of the outer member 3 with respect to the weight can be increased.

(2) circumferential opening width P ₁ of the plurality of recesses 3e is set to a dimension smaller than the circumferential pitch P ₂ between the contact points O _1, O ₂ with the outer raceway surface 3a of the rolling elements 4 of the wheel-side column Therefore, a plurality of contacts between the rolling element 4 and the outer raceway surface 3a are not positioned in the circumferential opening width of the single recess 3e. For this reason, compared with the case where the circumferential opening width of the recess is larger than the circumferential pitch of the contact point between the rolling element and the outer raceway surface, the vibration of the outer member 3 accompanying the rolling of the rolling element 4 is suppressed. can do.

  Although the wheel bearing device of the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the above-described embodiment, the case where the protrusion 3f is configured to form a lattice-shaped molded body has been described. However, the present invention is not limited to this, for example, as shown in FIG. You may comprise so that the some protrusion 51 may form a honeycomb-shaped molded object. In this case, the plurality of protrusions 51 have a plurality of recesses 52 each having a substantially regular hexagonal opening surface on a predetermined portion of the outer member 3 (in the same manner as in the above embodiment, on the outer peripheral side of the outer member). And formed on the portion excluding the connecting surface. Further, the circumferential opening width P ₁ of the plurality of recesses 52 (the interval between the circumferential central portions of the protrusions 51 adjacent in the circumferential direction) is relative to the outer raceway surface 3a of the rolling elements 4 in the wheel side row. It is set circumferentially smaller than the direction pitch _{P 2 (P 1 <P 2} ) dimension between the contacts _O 1, _{O 2.} In addition, the shape of the opening of the recess may be a polygon such as a triangle or a pentagon, or a circle other than a quadrangle and a hexagon.

(2) Also, for example, as shown in FIG. 6, a plurality of protrusions 61 extending in the axial direction are formed on the outer peripheral surface 30 a of the outer member 3, and the concave grooves 62 are respectively formed between the adjacent protrusions 61. It is good also as a formed structure. In this case, the plurality of concave grooves 62 extend in the axial direction of the outer member 3 and are arranged in parallel in the circumferential direction thereof.

(3) In the above embodiment, the plurality of recesses 3e are on the outer peripheral side of the outer member 3 and include the peripheral surface 31d of the vehicle body mounting flange 3d and the wheel side end surface 32d except for the connecting surfaces 3c and 30d. However, the present invention is not limited to this, and the plurality of recesses are formed on the outer peripheral side of the outer member and at least part of the portion excluding the connection surface connected to the vehicle body. It only has to be done. For example, the recess may be provided only in a region corresponding to the outer peripheral side of the outer raceway surface 3a of the outer member 3, or may be provided only in a region between the region and the wheel side flange end surface. Good.

(4) Although the case where the rolling elements 4 and 5 are made of steel balls has been described in the above embodiment, the present invention is not limited to this and may be a tapered roller.

DESCRIPTION OF SYMBOLS 1 ... Wheel bearing apparatus, 2 ... Inner member, 3 ... Outer member, 3a, 3b ... Outer raceway surface, 3c ... Connection surface, 3d ... Body mounting flange, 3f ... Projection, 30a ... Outer surface, 30d ... Connection surface, 31d ... Flange peripheral surface, 32d ... Wheel side flange end face, 4, 5 ... Rolling element, 51 ... Projection, 52 ... Recess, 6 ... Hub shaft, 6a ... Large diameter body, 6b ... Small diameter Body, 6c ... through hole, 6d ... wheel mounting flange, 60a ... inner raceway surface, 60b ... mounting surface, 60c ... serration, 60d ... bolt insertion hole, 61 ... projection, 61d ... wheel mounting surface, 62 ... concave , 7 ... inner ring, 7a ... inner raceway surface, 8 ... hub bolts, 9 ... knuckle, 10, 11 ... sealing member, O ... center axis, _{O 1,} O 2 _... contact, P 1 _... circumferential opening width, _{P 2} ... Circumferential pitch

Claims (2)

An inner member having an inner raceway surface formed on the outer periphery and a wheel mounting surface to which the wheel is mounted;
An outer member disposed on the outer periphery of the inner member and having an outer raceway surface formed on the inner periphery and a connecting surface connected to the vehicle body side;
A plurality of rolling elements disposed between the inner raceway surface and the outer raceway surface;
The outer member is set to a dimension smaller than the circumferential pitch of the contact points where the plurality of rolling elements are in contact with the outer raceway surface on the outer peripheral surface of the inner member closer to the wheel mounting surface than the connecting surface. A wheel bearing device in which a plurality of recesses having a circumferential opening width are formed.   The wheel bearing device according to claim 1, wherein the outer member is formed of a molded body formed together with the plurality of recesses by forging.

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