JP2006316804A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which is installed in a light metal knuckle, and prevented from the axial movement and the creep of an outer ring owing to a decrease in interference allowance following temperature rise. <P>SOLUTION: In the bearing device for the wheel of the first generation structure, a bearing 3 for the wheel is fitted in a small-diameter step 5 between a knuckle 2 and a hub ring 1, which are made of a light metal, an inner flange 19 is formed in an end of the inner periphery of the knuckle 2, a stopper ring groove 20 is formed in the other end, a stopper ring 21 is installed in the stopper ring groove 20, and the bearing 3 for the wheel is positioned and locked in the axial direction by the stopper ring 21 and the inner flange 19. A tapered surface 20a narrowing toward the groove bottom is formed in the outside wall surface of the stopper ring groove 20, and a tapered surface 21a corresponding to the tapered surface 20a is formed in one side of the stopper ring 21, so that even when the knuckle 2 expands beyond the outer ring 12 owing to the temperature rise, the axial movement of the outer ring 12 can be restricted by the stopper ring 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like with respect to a knuckle constituting a suspension device, and more particularly, an improved mounting method for fixing a wheel bearing to a light alloy knuckle. It is about.

  As shown in FIG. 5, a conventional wheel bearing device 50 includes a hub wheel 51 that fixes a wheel (not shown) together with a brake rotor 57, and rotatably supports the hub wheel 51. A wheel bearing 54 having an inner ring 53, a knuckle 55 that supports the wheel bearing 54 on a vehicle body (suspension device), and a hub wheel 51 connected to drive power of a drive shaft (not shown) to the hub wheel 51. A constant velocity universal joint 56 for transmission is configured as a main part.

  Conventionally, ferrous metals such as malleable cast iron having the same linear expansion coefficient as that of the hub wheel 51 and the like have been employed for the components constituting the wheel bearing device 50, in particular, the knuckle 55. There is a tendency to adopt a light alloy such as an aluminum alloy or a magnesium alloy for the purpose of making it easier. However, when the knuckle 55 is formed of such a light alloy, the knuckle 55 expands beyond the outer ring 52 due to, for example, a rise in temperature during traveling due to the difference in the linear expansion coefficient between the knuckle 55 and the outer ring 52, and is fitted to the outer ring 52. There was a risk that the amount of shimeshiro would be reduced or released. As a result, a problem such as so-called preload loss occurred in which the bearing preload during assembly cannot be maintained.

  If such preload loss occurs, the outer ring 52 may move in the axial direction or cause creep due to a moment load applied to the apparatus, which may cause seizure or a short life. Here, creep is a phenomenon in which the bearing surface slightly moves in the circumferential direction due to lack of mating squeeze or poor mating surface processing accuracy, and the mating surface becomes mirrored and sometimes seizes or welds with galling. Say.

  In order to avoid such a problem, in the conventional wheel bearing device 50, the inner periphery of the knuckle 55 is provided with an inner collar 58 at the end on the inboard side, and an annular retaining ring at the end on the outboard side. A groove 59 is formed. A retaining ring 60 is attached to the retaining ring groove 59, and the outer ring 52 is positioned and fixed in the axial direction by the retaining ring 60 and the inner flange 58. In addition, the initial preload amount is set high in order to ensure the bearing preload when the temperature rises, and the initial shimeiro is set to be large in anticipation of the amount of shimeshilo fall when the temperature rises. Note that there is no prior art document information to be described because the prior art is not related to a known literature invention.

  However, as shown in an enlarged view in FIG. 6, it is inevitable that an axial clearance δ is generated between the retaining ring 60 and the retaining ring groove 59 in consideration of dimensional variations and mounting properties in processing. . Therefore, when the knuckle 55 expands beyond the outer ring 52 due to a temperature increase during traveling, the axial clearance δ may further increase, and the movement of the outer ring 52 increases, which adversely affects traveling stability. The durability of the bearing may be reduced.

  Further, if the initial preload amount of the wheel bearing 54 is set to be high in order to prevent the preload from being lost, as a matter of course, an extra load is always applied to the wheel bearing 54 and the bearing life is shortened. In addition, the bearing stiffness varies with a large change in the preload amount due to a temperature change, which adversely affects the running stability of the vehicle. Furthermore, if the initial squeeze is set large in order to prevent creep, the knuckle 55 may be squeezed when the wheel bearing 54 is press-fitted. Therefore, it is necessary to press-fit the wheel bearing 54 with the knuckle 55 heated in advance. There is. This increases the number of assembly steps and causes a cost increase.

  The present invention has been made in view of such circumstances, and is mounted on a light alloy knuckle that has been reduced in weight, and prevents the outer ring from moving in the axial direction and from causing creep due to a decrease in shimeshiro accompanying temperature rise. An object of the present invention is to provide a bearing device for a vehicle.

  In order to achieve such an object, the invention according to claim 1 of the present invention constitutes a suspension device, and has a knuckle made of a light alloy and a wheel mounting flange at one end integrally. A hub ring formed with a small-diameter step portion extending in the axial direction and a wheel bearing fitted between the small-diameter step portion of the hub ring and the knuckle. An outer ring formed with an outer rolling surface of the row, a pair of inner rings interpolated in the outer ring and formed with an inner rolling surface facing the outer rolling surface of the double row on the outer circumference, and the both rolling A double row rolling element housed between the running surfaces so as to roll freely, an inner collar is formed at one end of the inner periphery of the knuckle, and an annular retaining ring groove is formed at the other end. A retaining ring comprising a ring with a ring is attached to the retaining ring groove, and the retaining ring and the inner flange In the wheel bearing device in which the wheel bearing is positioned and fixed in the axial direction, a tapered surface that is narrower toward the groove bottom of the retaining ring groove is formed on the outer wall surface of the retaining ring groove. A configuration is adopted in which a tapered surface corresponding to the tapered surface is formed on one side surface of the retaining ring.

  Thus, the wheel bearing is fitted between the knuckle made of light alloy and the small-diameter step portion of the hub wheel, the inner collar is formed at one end portion of the inner periphery of the knuckle, and the annular retaining ring groove is formed at the other end. In the first-generation wheel bearing device of the first generation structure, a retaining ring comprising an end ring is mounted in the retaining ring groove, and the wheel bearing is axially positioned and fixed by the retaining ring and the inner flange. In addition, a tapered surface narrowing toward the groove bottom of the retaining ring groove is formed on the outer wall surface of the retaining ring groove, and a tapered surface corresponding to the tapered surface is formed on one side surface of the retaining ring. Therefore, even if the knuckle expands beyond the outer ring due to temperature rise, it is possible to prevent the axial clearance between the retaining ring groove and the retaining ring, and to regulate the axial movement of the outer ring. .

  Preferably, even if an axial load is applied to the retaining ring via the outer ring as long as the inclination angle of the tapered surface is set in a range of 10 to 30 ° as in the invention described in claim 2. The component force in the direction of reducing the diameter of the retaining ring is reduced, and a desired pull-out resistance can be ensured.

  Further, as in the invention according to claim 3, if an annular groove is formed on the outer periphery of the outer ring and a resin band made of a heat-resistant synthetic resin is filled in the annular groove by injection molding, the temperature rises. Even if the knuckle expands more than the outer ring, the resin band suppresses the decrease in mating squeezing with the outer ring, preventing the occurrence of bearing creep and preventing the initially set bearing preload from decreasing. Therefore, the desired durability can be ensured by suppressing fluctuations in bearing rigidity.

Further, as in the invention described in claim 4, if the resin band is made of a polyamide-based synthetic resin and the linear expansion coefficient is set to 8 to 16 × 10 ⁻⁵ / ° C., the linear expansion of the knuckle Even if the knuckle is larger than the coefficient and thermally expands more than the wheel bearing, the resin band can expand more than the thermal expansion of the knuckle and follow the change.

  In the invention according to claim 5, since the resin band is formed to have a predetermined outer diameter by grinding after molding, the squeezing with the knuckle is stabilized, and preload loss and bearing creep are more effective. In addition, at the time of press-fitting, there is no loss of the resin band due to excessive shishiro.

  The wheel bearing device according to the present invention constitutes a suspension device, and has a knuckle made of a light alloy and a wheel mounting flange integrally formed at one end, and a small-diameter step portion extending in the axial direction from the wheel mounting flange is formed. A hub wheel, and a wheel bearing fitted between the small diameter step portion of the hub wheel and the knuckle. The wheel bearing has a double row outer raceway formed on the inner periphery. An outer ring, a pair of inner rings that are inserted into the outer ring and formed on the outer periphery and facing the outer rolling surfaces of the double row, respectively, and a pair of inner rings that are freely rollable between the rolling surfaces. A double row rolling element, an inner collar is formed at one end of the inner periphery of the knuckle, an annular retaining ring groove is formed at the other end, and a retaining ring made of an end ring is formed in the retaining ring groove. A wheel is mounted, and the wheel bearing is axially positioned by the retaining ring and the inner flange. In the specified wheel bearing device, a tapered surface narrowing toward the groove bottom of the retaining ring groove is formed on the outer wall surface of the retaining ring groove, and a tapered surface corresponding to the tapered surface is formed. Since it is formed on one side of the retaining ring, even if the knuckle expands beyond the outer ring due to temperature rise, it prevents the axial clearance between the retaining ring groove and the retaining ring from occurring, Axial movement can be restricted by this retaining ring.

  A suspension wheel, a knuckle made of a light alloy, a hub wheel integrally formed with a wheel mounting flange at one end and a small-diameter step portion extending in the axial direction from the wheel mounting flange, and a small diameter of the hub wheel A wheel bearing fitted between the stepped portion and the knuckle, and the wheel bearing is inserted into the outer ring having a double row outer raceway formed on the inner periphery, A pair of inner rings each formed with an inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a double row rolling element accommodated so as to roll between the rolling surfaces; An inner collar is formed at one end of the inner periphery of the knuckle, an annular retaining ring groove is formed at the other end, and a retaining ring made of an end ring is attached to the retaining ring groove. In a wheel bearing device in which the wheel bearing is axially positioned and fixed by an inner shaft. A tapered surface that is narrower toward the groove bottom of the retaining ring groove is formed on the outer wall surface of the retaining ring groove, and a tapered surface corresponding to the tapered surface is formed on one side surface of the retaining ring. In addition, the inclination angle of the tapered surface is set in a range of 10 to 30 °.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is a longitudinal sectional view showing an embodiment of a wheel bearing according to the present invention, and FIG. FIG. 4A is a front view showing a retaining ring according to the present invention, and FIG. 4B is a longitudinal sectional view thereof. In the following description, the side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing).

  The wheel bearing device shown in FIG. 1 mainly includes a hub wheel 1 and a wheel bearing 3 that is press-fitted into the hub wheel 1 and rotatably supports the hub wheel 1 with respect to the knuckle 2. The hub wheel 1 is formed of medium carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and the wheel mounting flange 4 for mounting the wheel W and the brake rotor B to the end on the outboard side, and the wheel A cylindrical small diameter step portion 5 extending in the axial direction from the mounting flange 4 is formed. Hub bolts 4 a that fasten the wheels W and the brake rotor B are planted on the wheel mounting flange 4 at equal intervals in the circumferential direction. Further, a serration (or spline) 6 for torque transmission is formed on the inner peripheral surface of the hub wheel 1, and a wheel bearing 3 described later is press-fitted on the outer peripheral surface of the small diameter step portion 5.

  The wheel bearing 3 press-fitted into the small-diameter step portion 5 of the hub wheel 1 is fixed in a state of being sandwiched between the shoulder portion 9 of the outer joint member 8 constituting the constant velocity universal joint 7 and the hub wheel 1. The outer joint member 8 is integrally formed with a stem portion 10 extending in the axial direction from the shoulder portion 9. A serration (or spline) 10 a that engages the serration 6 of the hub wheel 1 and a screw portion 10 b are formed on the outer periphery of the stem portion 10. Torque from the engine is transmitted to the hub wheel 1 via a drive shaft and a constant velocity universal joint 7 (not shown) and a serration 10 a of the stem portion 10.

  Here, the serration 10a of the stem portion 10 is provided with a torsion angle inclined at a predetermined angle with respect to the axis, and the shoulder portion 9 of the outer joint member 8 abuts against the wheel bearing 3 (the large end surface of the inner ring 13). The stem portion 10 is press-fitted and fitted to the hub wheel 1. Thereby, preload is given to the fitting part of serrations 6 and 10a, and the play of the peripheral direction is killed. Further, the fixing nut 11 is fastened with a predetermined tightening torque to the screw portion 10b formed at the end portion of the stem portion 10, so that a desired bearing preload can be obtained. That is, the wheel bearing 3 is press-fitted with a predetermined squeezing force so as to prevent occurrence of bearing creep and achieve a desired preload amount. On the other hand, the knuckle 2 is formed of a light alloy such as an aluminum alloy. Thereby, compared with conventional cast iron etc., even if each part is designed to be thick in order to make up for lack of rigidity, the weight is reduced by half, and weight reduction can be achieved. A wheel bearing 3 is press-fitted into the knuckle 2 with a predetermined scissors.

  As shown in an enlarged view in FIG. 2, the wheel bearing 3 is composed of an outer ring 12, a pair of inner rings 13 and 13 inserted in the outer ring 12, and a double-row rolling accommodated between the inner and outer rings 13 and 12. It consists of a double row angular contact ball bearing provided with moving bodies (balls) 14 and 14. The outer ring 12 is made of high carbon chrome bearing steel such as SUJ2, and double row outer rolling surfaces 12a and 12a are integrally formed on the inner periphery. The inner ring 13 is made of high carbon chrome bearing steel such as SUJ2, and inner rolling surfaces 13a and 13a facing the double row outer rolling surfaces 12a and 12a are formed on the outer periphery thereof. And the double row rolling elements 14 and 14 are accommodated between these rolling surfaces 12a and 13a, respectively, and are hold | maintained by the holder | retainers 15 and 15 so that rolling is possible. Further, seals 16 and 16 are attached to the end portion of the wheel bearing 3 to prevent leakage of the lubricating grease sealed inside the bearing and intrusion of rainwater, dust and the like from the outside into the bearing. In addition, although the double row angular contact ball bearing which used the ball for the rolling element 14 was illustrated here, the wheel bearing 3 which concerns on this invention is not restricted to this, The double row cone which used the tapered roller for the rolling element 14 It may be a bearing.

  A pair of annular grooves 17 and 17 are formed on the outer periphery of the outer ring 12. These annular grooves 17 and 17 are respectively set at positions approximately in the center of the projected width of the rolling element 14, that is, at the groove bottom positions of the double row outer rolling surfaces 12a and 12a. Thereby, expansion of the groove bottom region which becomes the minimum thickness portion can be suppressed, and preload loss and bearing creep can be effectively prevented. The annular grooves 17 and 17 are filled with a heat-resistant thermoplastic synthetic resin based on PA (polyamide) 11 by injection molding to form a resin band 18.

The material of the resin band 18 is not limited to the PA 11, but is larger than the linear expansion coefficient (2 to 2.3 × 10 ⁻⁵ / ° C.) of the knuckle 2 made of a light alloy such as an aluminum alloy, and the linear expansion coefficient is 8 to 16 It may be a synthetic resin in the range of × 10 ⁻⁵ / ° C., for example, PA66, PA6, etc., and those in which reinforcing fibers such as GF (glass fiber) are contained in the range of 10-30 wt% in these thermoplastic synthetic resins It can be illustrated.

  In the wheel bearing according to the present embodiment, since the resin band 18 is formed on the outer periphery of the outer ring 12, even if the knuckle 2 expands beyond the outer ring 12 due to a temperature rise, a decrease in fitting squealing with the outer ring 12 is reduced. Can be suppressed by the resin band 18 and the occurrence of bearing creep can be prevented, and the initial bearing preload can be prevented from being lowered, thereby suppressing the fluctuation of the bearing rigidity and improving the running stability of the vehicle. Can be surely kept.

  In addition, after the resin band 18 is injection-molded in the annular groove 17 of the outer ring 12, the outer peripheral surface of the resin band 18 is ground by a centerless grinding machine or the like, so that a predetermined outer diameter is formed. As a result, the squeezing with the knuckle 2 can be stabilized, preload loss and bearing creep can be more effectively prevented, and the resin band 18 is not lost due to excessive squeezing during press-fitting. Note that, after the resin band 18 is molded, the outer peripheral surface of the outer ring 12 and the resin band 18 may be ground integrally.

  As shown in FIG. 1, the wheel bearing 3 is provided with an inner collar 19 at the end on the inboard side and an annular stopper at the end on the outboard side, as in the prior art. A ring groove 20 is formed, and a retaining ring 21 is attached to the retaining ring groove 20, and the outer ring 12 is positioned and fixed in the axial direction by the retaining ring 21 and the inner collar 19.

  Here, as shown in an enlarged view in FIG. 3, the retaining ring 21 is elastically attached to the retaining ring groove 20 in a reduced diameter, but the retaining ring groove 20 is on the outboard side (the bearing outer side). The taper surface 20a which becomes narrow toward the groove bottom is formed on the wall surface. A tapered surface 21 a having an inclination angle corresponding to the tapered surface 20 a of the retaining ring groove 20 is formed on one side surface of the retaining ring 21. By engaging both the tapered surfaces 20a and 21a, the axial clearance between the retaining ring groove 20 and the retaining ring 21 is kept substantially zero.

  Further, as shown in FIG. 4, the retaining ring 21 is a ring that is divided in one place in the circumferential direction, so that the retaining ring 21 can be attached to the retaining ring groove 20 in a reduced diameter state. It can be elastically deformed and restored, and can be engaged with the retaining ring groove 20 without gaps. Further, even if the knuckle 2 expands beyond the outer ring 12 due to temperature rise, the retaining ring 21 follows in a state of being in close contact with the retaining ring groove 20, so that an axial clearance is generated between the retaining ring 21 and the retaining ring groove 20. Can be prevented. When the axial load is applied to the retaining ring 21 via the outer ring 12, the inclination angle α of the tapered surface 21a is α ≦ 45 ° so that the component force in the direction of reducing the diameter of the retaining ring 21 does not increase. Preferably, α is set in a range of 10 to 30 °.

  In the present embodiment, the retaining ring 21 in which the tapered surface 20a is formed on the wall surface on the outboard side of the retaining ring groove 20 and the tapered surface 21a having the inclination angle α corresponding to the tapered surface 20a is thus formed. Since it is elastically attached, even if the knuckle 2 expands beyond the outer ring 12 due to a temperature rise, an axial clearance δ is prevented from being generated between the retaining ring groove 20 and the retaining ring 21, and the outer ring 12 Axial movement can be restricted.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a first generation structure in which a knuckle constituting a suspension device is made of a light alloy such as an aluminum alloy having a larger linear expansion coefficient than steel.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a longitudinal cross-sectional view which shows a wheel bearing same as the above. It is a principal part enlarged view of FIG. (A) is a front view which shows the retaining ring which concerns on this invention. (B) is a longitudinal cross-sectional view same as the above. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is a principal part enlarged view of FIG.

Explanation of symbols

1 ... hub wheel 2 ... knuckle 3 ... wheel bearing 4 ... wheel mounting flange 4a ... ... Hub rolling element 5 ......... Small diameter step 6, 10a ... Serration 7 ... Constant velocity universal joint 8 ... Outside Joint member 9 ... shoulder 10 ... stem 10b ... screw 11 ... fixing nut 12 ... Outer ring 12a ... Outer rolling surface 13 ... Inner ring 13a ... Inner rolling surface 14 ... Rolling element 15 ... Cage 16 ······ Seal 17 ··············································································· Ring grooves 20a, 21a ... Tapered surface 21 ... ... Retaining ring 50 ········· Wheel bearing device 51 ··········································· Outer ring 53 ... Wheel bearings 55 ... Knuckle 56 ... Constant velocity universal joint 57 ... Brake rotor 58 ... Inner flange 59 ... ...... Retaining ring groove 60 ... Retaining ring B ... Brake rotor W ... Wheel δ ... Axial direction Clearance α ・ ・ ・ Inclination angle

Claims (5)

The suspension system is composed of a knuckle made of light alloy,
A hub wheel integrally having a wheel mounting flange at one end, and a small-diameter step portion extending in the axial direction from the wheel mounting flange;
It consists of a wheel bearing fitted between the small diameter step of the hub wheel and the knuckle,
This wheel bearing comprises an outer ring having a double row outer raceway formed on the inner periphery,
A pair of inner rings that are inserted into the outer ring and formed with inner rolling surfaces facing the outer rolling surfaces of the double row on the outer circumference;
A double row rolling element housed between the rolling surfaces so as to roll freely,
An inner collar is formed at one end of the inner periphery of the knuckle, an annular retaining ring groove is formed at the other end, and a retaining ring made of an end ring is attached to the retaining ring groove. In the wheel bearing device in which the wheel bearing is positioned and fixed in the axial direction by an inner shaft,
A tapered surface having a narrow width toward the groove bottom of the retaining ring groove is formed on the outer wall surface of the retaining ring groove, and a tapered surface corresponding to the tapered surface is formed on one side surface of the retaining ring. A bearing device for a wheel.   The wheel bearing device according to claim 1, wherein an inclination angle of the tapered surface is set in a range of 10 to 30 °.   The wheel bearing device according to claim 1 or 2, wherein an annular groove is formed on an outer periphery of the outer ring, and a resin band made of heat-resistant synthetic resin is filled in the annular groove by injection molding. 4. The wheel bearing device according to claim 1, wherein the resin band is made of a polyamide-based synthetic resin, and a linear expansion coefficient thereof is set to 8 to 16 × 10 ⁻⁵ / ° C. 4.   The wheel bearing device according to any one of claims 1 to 4, wherein the resin band is formed to have a predetermined outer diameter by grinding after molding.

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