JP4535394B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device composed of a double row tapered roller bearing that rotatably supports a wheel of an automobile or the like, and more particularly, a wheel that achieves a light weight, a compact size, and a long life by increasing a load capacity. The present invention relates to a bearing device.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like supports a hub wheel for mounting a wheel rotatably via a double row rolling bearing, and includes a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. This wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double-row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device, and is an outer member. 2nd generation structure with body mounting flange or wheel mounting flange formed directly on the outer periphery of the wheel, 3rd generation structure with one inner rolling surface formed directly on the outer periphery of the hub wheel, or constant speed with the hub wheel It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the universal joint.

  In vehicles with heavy vehicle body weight, such as off-road cars and trucks, in recent years, the horsepower and loading capacity of vehicles have increased, and with this, the wheel bearing device can withstand the temperature rise during high loads and high speeds. Is required. Furthermore, there is a growing demand for long-term maintenance-free operation. Tapered roller bearings that have a large load capacity and are suitable for carrying a radial load, a thrust load, and a combined load of these are generally used for bearing portions of wheel bearing devices in such vehicles.

  An example of such a tapered roller bearing is shown in FIG. The tapered roller bearing 50 includes an outer ring 51, an inner ring 52, a tapered roller 53 disposed between the outer ring 51 and the inner ring 52, and a cage 54 that holds the tapered roller 53. . The outer ring 51 has a tapered outer raceway surface 51a formed on the inner periphery. Further, the inner ring 52 has a tapered inner rolling surface 52a facing the outer rolling surface 51a on the outer periphery. On the large diameter side of the inner rolling surface 52a, a large flange 52b that contacts the large diameter end portion of the tapered roller 53 and guides the tapered roller 53, and on the small diameter side, a small flange 52c that prevents the tapered roller 53 from falling off. Are integrally formed.

  The cage 54 includes a small-diameter-side annular portion 54a, a large-diameter-side annular portion 54b, a plurality of column portions 54c that connect the small-diameter-side annular portion 54a and the large-diameter-side annular portion 54b in the axial direction, and a circumferential direction. A plurality of pockets 54d that are provided between the adjacent column portions 54c and accommodate the tapered rollers 53 in a rollable manner are provided.

Here, as shown in FIG. 5B, a protruding portion 54f that is convex toward the outer raceway surface 51a of the outer ring 51 is integrally formed on the outer diameter surface of the column portion 54c. The projecting portion 54f has a circular cross-sectional contour shape of the column portion 54c, and the arc-shaped curvature radius R2 is smaller than the curvature radius R1 of the outer rolling surface 51a. As a result, a good wedge-shaped oil film is formed between the protrusion 54f and the outer rolling surface 51a. Even when the PCD (pitch circle diameter) of the retainer 54 is increased and brought close to the outer ring 51, the tapered roller bearing 50 Can be rotated without causing large friction or torque loss, and the number of tapered rollers 53 can be increased without difficulty.
JP 2005-98316 A

  However, even if such a tapered roller bearing 50 is to be applied to a wheel bearing device, there are cases where the rolling life cannot satisfy the requirements although the rigidity required for the vehicle is satisfied due to the limitation of the specifications and size of the bearings. Thus, as a means for extending the rolling life, for example, it is conceivable to increase the length of the tapered roller 53. However, this is not preferable because the bearing width becomes larger and the design of bearing peripheral parts is changed.

  For example, when the tapered roller bearing 50 described above is applied to a wheel bearing 55 having a first generation structure as shown in FIG. 6A, double row outer raceway surfaces 51a and 51a of an outer ring 56 and a pair of inner rings. There is a limit in increasing the length of the double-row tapered rollers 53 and 53 accommodated between the inner rolling surface 52a of 52. That is, if the large diameter side of the tapered roller 53 is extended, the strength of the large collar 52b of the inner ring 52 is insufficient, and if the small diameter side is extended, a pair of retainers 54, 54 are enlarged as shown in FIG. It is not possible to secure an axial clearance e for preventing interference.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wheel bearing device that achieves a light weight and a compact size and increases a load capacity to extend a life.

In order to achieve such an object, the invention according to claim 1 of the present invention comprises an outer member formed integrally with an outer rolling surface of a tapered double row that is outwardly opened on the inner periphery, and an outer periphery. An inner member formed with a tapered double-row inner rolling surface facing the outer row of the double row, and a cage disposed between the outer member and the inner member, In a wheel bearing device including a double row tapered roller that is rotatably accommodated between the rolling surfaces of the inner member and the outer member via the cage, the wheel bearing device includes: Each outer diameter is different, the outer diameter of at least the small diameter side of one cage is formed smaller than the inner diameter of the smaller diameter side of the other cage, and the smaller diameter side of the one cage is the smaller diameter of the other cage Partly interpolated on the side .

Thus, in the wheel bearing device of the first to fourth generation structure constituted by the back-to-back type double row tapered roller bearing in which the double row tapered rollers are accommodated so as to roll freely through the cage, The outer diameters of the cages in the double row are different, the outer diameter of at least the small diameter side of one of the cages is formed smaller than the inner diameter of the smaller diameter side of the other cage, and the smaller diameter side of one of the cages is Since it is partially inserted on the small diameter side of the cage, there is no interference between the cages even if the small diameter side of the tapered roller is extended and set long, and it is light and compact without changing the bearing width. In addition, it is possible to provide a wheel bearing device in which the load capacity is increased to extend the life.

Further, as in the invention described in claim 2 , the outer diameter of one of the double row cages is formed to be smaller than the pitch circle diameter of each row of the double row tapered rollers. If the outer diameter of the other cage is formed to be large, the strength of the cage column can be secured and a large number of tapered rollers can be accommodated, and the small diameter side of the tapered roller can be extended. Can be set longer.

Further, as in the invention described in claim 3 , one of the double row cages is configured as an inner holding type, and the inner diameter of the cage is arranged on the inner rolling surface via a radial clearance. And the other cage is configured as an outer holding type, and the outer diameter of the cage is opposed to the outer rolling surface via a radial clearance, the column of the cage The strength can be secured and a large number of tapered rollers can be accommodated, and the rolling life of the bearing can be increased.

According to a fourth aspect of the present invention, in at least one bearing row of the double row tapered roller bearings, a large hook that contacts the large end surface of the tapered roller and guides the tapered roller is provided on the inner side. If it is not formed on the member side and is integrally formed on the large diameter side of the outer rolling surface of the outer member, the tapered roller avoids the interference between the cages regardless of the specification of the tapered roller. Can be lengthened, and the degree of freedom in design is expanded.

The wheel bearing device according to the present invention includes an outer member formed integrally with a tapered double row outer rolling surface that opens outward on the inner periphery, and the outer rolling surface of the double row on the outer periphery. An inner member formed with a tapered double-row inner rolling surface opposed to the outer member, a cage disposed between the outer member and the inner member, and the inner member and the outer member. In a wheel bearing device including a double row tapered roller that is rotatably accommodated between the rolling surfaces via the cage, the outer diameters of the double row cages are different from each other. Since the outer diameter of at least the small diameter side of the cage is smaller than the inner diameter of the small diameter side of the other cage, the small diameter side of the one cage is partially inserted into the small diameter side of the other cage. Even if the small diameter side of the tapered roller is extended and set longer, there is no interference between the cages and the bearing width can be changed. Together reduce the weight and size without thereby increasing the load capacity it is possible to provide a wheel bearing apparatus which attained a long life.

A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, a small-diameter step portion extending in the axial direction from the wheel-mounting flange, and a small diameter step portion of the hub wheel via a predetermined shimiro A wheel bearing device having wheel bearings press-fitted in the above-mentioned manner, wherein the wheel bearing has a body mounting flange integrally attached to the suspension on the outer periphery and opens outwardly on the inner periphery. An outer member formed with a tapered double row outer rolling surface, a pair of inner rings formed with a tapered inner rolling surface facing the outer rolling surface of the double row on the outer periphery, In the wheel bearing device constituted by a back-to-back type double row tapered roller bearing provided with a double row tapered roller accommodated in a freely rolling manner between both rolling surfaces via a cage, the double row Of tapered roller bearings on the outer side But the contact with the large end faces of the tapered rollers is large rib for guiding the tapered rollers is not formed on the inner ring, with which is formed on the large diameter side of the outer raceway surfaces in the outer member, The cage of this bearing row is configured as an inner holding type, and the inner diameter of the holding unit is opposed to the inner raceway surface of the inner ring via a slight radial clearance, and the other holding unit is an outer holding type. The outer diameter of the cage is opposed to the outer rolling surface through a slight radial clearance, and the smaller diameter side of the outer cage is partially inserted into the smaller diameter side of the cage. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 (a) is a sectional view taken along the line AA of FIG. 1, and FIG. 1 (b) is a sectional view of FIG. BB arrow sectional drawing and FIG. 3 are the principal part enlarged views of FIG. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  This wheel bearing device has a second generation structure on the drive wheel side, and includes a hub wheel 1 and a wheel bearing 2 press-fitted into the hub wheel 1. The hub wheel 1 integrally has a wheel mounting flange 3 for attaching a wheel (not shown) to an end portion on the outer side, and a cylindrical small-diameter step portion 1b extending in the axial direction on the outer periphery via a shoulder portion 1a. And a serration (or spline) 1c for torque transmission is formed on the inner periphery. Further, hub bolts 3 a are implanted at circumferentially equidistant positions on the wheel mounting flange 3.

  The hub wheel 1 is formed of medium carbon steel (carbon steel for SC system mechanical structure of JIS standard) containing 0.40 to 0.80 wt% of carbon such as S53C, and has a small diameter from the shoulder portion 1a which is the base of the wheel mounting flange 3. The surface is hardened in the range of 50 to 64 HRC by induction hardening over the stepped portion 1b. In addition, the crimping part 10 mentioned later is left raw with a surface hardness of 25 HRC or less after forging. As a result, the strength of the hub wheel 1 is improved, and fretting wear on the fitting surface of the wheel bearing 2 is suppressed, thereby improving durability. Moreover, the workability of the caulking portion 10 can be improved and the occurrence of cracks and the like due to plastic deformation can be prevented.

  The wheel bearing 2 has a vehicle body mounting flange 4c integrally attached to a knuckle (not shown) on the outer periphery, and has a tapered double row outer rolling surface 4a that opens outward on the inner periphery. An outer member 4 formed with 4b, inner rings 5 and 6 formed with tapered inner rolling surfaces 5a and 6a on the outer periphery facing the double-row outer rolling surfaces 4a and 4b, and both rolling surfaces Double-row tapered rollers 9 and 9 are accommodated so as to be freely rollable via cages 7 and 8 therebetween. And the back-to-back type double row tapered roller bearing set in a state in which the end surfaces (front end surfaces) on the small diameter side of the inner rings 5 and 6 are abutted is configured.

  The outer member 4, the inner rings 5, 6 and the tapered roller 9 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching. The outer member 4 is not limited to the high carbon chrome steel, but is formed of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, as in the case of the hub wheel 1, and at least double row outer rolling surfaces. 4a and 4b may be hardened by induction hardening in the range of 58 to 64 HRC.

  The wheel bearing 2 is press-fitted into the small-diameter step portion 1b through a predetermined squeeze in a state where the outer ring 5 is in contact with the shoulder 1a of the hub wheel 1. And it fixes in the state to which the predetermined bearing preload was provided by the crimping part 10 formed by carrying out the plastic deformation of the edge part of the small diameter step part 1b to radial direction outward. As a result, the self-retained structure that can maintain a stable preload over a long period of time without adjusting the preload by adjusting the tightening torque of the nut and the like as well as reducing the weight and downsizing is provided. be able to.

  In addition, seals 11 and 12 are attached to openings of an annular space formed between the outer member 4 and the inner rings 5 and 6. These seals 11 and 12 constitute a so-called pack seal composed of an annular seal plate and a slinger that have a substantially L-shaped cross section and are arranged to face each other. These seals 11 and 12 prevent leakage of the lubricating grease sealed inside the bearing and intrusion of rainwater, dust and the like from the outside into the bearing.

  Here, in the present embodiment, in the inner bearing row, a large flange 6b is formed on the large diameter side of the inner raceway surface 6a of the inner ring 6, and the tapered roller 9 is brought into contact with the large end surface of the tapered roller 9. I am guiding you. On the other hand, in the outer side bearing row, a large flange for guiding the tapered roller 9 is not formed on the large diameter side of the inner rolling surface 5a of the inner ring 5, and the outer rolling surface 4a of the outer member 4 is large. A large collar 4d is integrally formed on the radial side. Thereby, irrespective of the specification of the tapered roller 9, interference between cages 7 and 8 described later can be avoided, the length of the tapered roller 9 can be increased, and the degree of freedom in design is expanded.

  The cages 7 and 8 are based on PA (polyamide resin) 46 and are formed by injection molding from a thermoplastic synthetic resin containing a reinforcing material such as CF (carbon fiber) or GF (glass fiber). The outer-side cage 7 is constituted by an inner-cage-type cage, and the inner-side cage 8 is constituted by an outer-cage-type cage. That is, as shown in an enlarged view in FIG. 2A, the outer cage 7 holds the tapered roller 9 on the inner diameter side with respect to the PCD (pitch circle diameter) of the tapered roller 9, and the inner diameter of the cage 7. Is configured to face the inner rolling surface 5a through a slight radial clearance. On the other hand, the retainer 8 on the inner side holds the tapered roller 9 on the outer diameter side with respect to the PCD of the tapered roller 9, as shown in an enlarged view in FIG. It is comprised so that the outer side rolling surface 4b may be opposed through a radial clearance. Thereby, the strength of the column portions 7a and 8a of the cages 7 and 8 can be ensured to accommodate as many tapered rollers 9 as possible, and the rolling life of the bearing can be increased.

  Furthermore, in this embodiment, as shown in FIG. 3, since the small diameter side of the outer cage 7 is partially inserted into the small diameter side of the inner cage 8, the interference between the cages 7 and 8 is prevented. Without consideration, the tapered rollers 9 and 9 can be set longer by extending the small diameter side, reducing the bearing weight without changing the bearing width, and increasing the load capacity for longer life. A wheel bearing device can be provided.

  Further, here, the cages 7 and 8 are made of synthetic resin formed by injection molding, but the wheel bearing device of the present invention is not limited to this. A steel plate cage may be used. If the cages 7 and 8 are made of synthetic resin formed by injection molding, the cost can be reduced, and the weight is lighter and the coefficient of friction is smaller than the cage made of steel plate press. It is suitable for reducing torque loss and cage wear.

  FIG. 4 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. In addition, the same code | symbol is attached | subjected to the site | part which has the same components same part as embodiment mentioned above, or the same function, and the detailed description is abbreviate | omitted.

  This wheel bearing device has a first generation structure and is mounted on an axle or hub wheel (not shown) to rotatably support the wheel. The wheel bearing 13 constituting the wheel bearing device is composed of a double-row tapered roller bearing, and is formed with an outer circumferential surface formed with tapered double-row outer rolling surfaces 14a, 14a opened outwardly on the inner circumference. A pair of inner races 15 and 15 having a side member 14 and a tapered inner rolling surface 15a facing the outer circumferential rolling surfaces 14a and 14a in a double row on the outer periphery, and a cage 16 between both rolling surfaces, And double-row tapered rollers 9, 9 which are accommodated so as to be rollable via 8. A back-to-back type double-row tapered roller bearing is set in a state in which the end faces on the small diameter side of the inner rings 15 and 15 are butted. In addition, a shield plate 17 and a seal 12 are attached to the opening of the annular space formed between the outer member 14 and the inner rings 15, 15, respectively. It prevents rainwater and dust from entering the bearing.

  A large flange 15b is integrally formed on the large diameter side of the inner raceway 15a of the inner ring 15, and abuts against the large end surface of the tapered roller 9 to guide the tapered roller 9. An annular groove 18 is formed in the inner periphery of the end portion on the small diameter side, which is a butting portion between the pair of inner rings 15, 15, and a connecting ring 19 having a substantially U-shaped cross section is attached to the annular grooves 18, 18. . The connecting ring 19 is formed by pressing a steel plate and its surface is hardened. Examples of the steel plate include a carbon tool steel plate such as SK5, a stainless steel plate such as SUS304, a cold rolled steel plate such as SPCC, and the like. Then, the connecting ring 19 is elastically deformed and mounted in the annular groove 18, whereby the pair of inner rings 15, 15 are firmly connected in the axial direction without play, and the workability of disassembling / assembling the wheel bearing 13 is simplified. Can be Further, since the pair of inner rings 15, 15 press-fitted and fixed to the axle or the like can be removed integrally during repair or the like, there is no problem that only the inner-side inner ring 15 remains on the axle.

  Here, in the present embodiment, the outer retainer 16 is configured as an outer holding type whose outer diameter is larger than that of the PCD of the tapered roller 9, similar to the inner retainer 8. However, the outer cage 16 is formed to have a smaller diameter than the inner cage 8. As described above, regardless of the type of the outer holding type and the inner holding type, the outer diameters of the cages 16 and 8 that hold the double-row tapered rollers 9 and 9 are different, and at least the small-diameter side of one of the cages 16 is provided. If the outer diameter is smaller than the inner diameter of the other cage 8 on the smaller diameter side, the outer cage 16 can be partially inserted into the inner cage 8 as in the above-described embodiment. Even if the small diameter side of the tapered rollers 9 and 9 is extended and set long, the cages 16 and 8 do not interfere with each other, and the weight and size are reduced without changing the bearing width, and the load capacity is increased. To extend the service life.

  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 comprises a back-to-back type double-row tapered roller bearing regardless of inner ring rotation or outer ring rotation type, and supports the first to fourth generations for rotatably supporting the wheel with respect to the vehicle body. The present invention can be applied to a wheel bearing device having a structure.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. (A) is AA arrow sectional drawing of FIG. (B) is BB arrow sectional drawing of FIG. It is a principal part enlarged view of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. (A) is a longitudinal cross-sectional view which shows the conventional tapered roller bearing. (B) is a fragmentary sectional view of (a). (A) is a longitudinal cross-sectional view which shows the wheel bearing apparatus to which the tapered roller bearing of FIG. 5 is applied. (B) is the principal part enlarged view of (a).

Explanation of symbols

1 ... hub wheel 1a ... shoulder 1b ... small diameter step 1c ... ... Serrations 2, 13 ... Wheel bearings 3 ... Wheel mounting flanges 3a ... ····································· Hub bolts 4 and 14 ··· Outer members 4a, 4b and 14a ··· Outer rolling surface 4c ·······・ Vehicle mounting flanges 4d, 6b, 15b... Large cage 5, 6, 15... Inner rings 5a, 6a, 15a. ··········· Retainer 7a, 8a ···································································· .... Clamping parts 11, 12 ... Seal 17 ... ············································································ .... Tapered roller bearings 51, 56 ... Outer ring 51a ... Outer rolling surface 52 ... Inner ring 52a・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 52b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Omine 52c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Kominato 53 ・ ・ ・ ・ ・ ・·······································································. Large-diameter annular part 54c ... pillar part 54d ... pocket 54f ... projection part 55 ...・ ・ ・ ・ ・ ・ ・ ・ Wheel bearing e ・ ・ ・ ・ ・ ・ ・ ・ Axial shaft Or R1 ············ arcuate curvature radius of curvature of the outer raceway surfaces radius R2 ············ cage

Claims (4)

An outer member formed integrally with a tapered double-row outer rolling surface that opens outward on the inner circumference;
An inner member having a tapered double-row inner rolling surface formed on the outer periphery, facing the double-row outer rolling surface;
A cage disposed between the outer member and the inner member;
In a wheel bearing device comprising a double row tapered roller accommodated so as to be able to roll between the rolling surfaces of the inner member and the outer member via the cage,
The outer diameters of the double row cages are different, the outer diameter of at least the small diameter side of one cage is formed smaller than the inner diameter of the smaller diameter side of the other cage, and the smaller diameter side of the one cage is A bearing device for a wheel, wherein the wheel bearing device is partially inserted on the small diameter side of the other cage . The outer diameter of one of the double row cages is formed to be small with respect to the pitch circle diameter of each row of the double row tapered rollers, and the outside diameter of the other cage is formed to be large. The wheel bearing device according to claim 1, wherein One of the double row cages is an inner holding type, and the inner diameter of the cage is opposed to the inner rolling surface via a radial clearance, and the other cage is an outer cage. The wheel bearing device according to claim 1, wherein the wheel bearing device is configured as a hugging shape, and an outer diameter of the cage is opposed to the outer rolling surface via a radial clearance. In at least one of the double row tapered roller bearings, the outer member is not formed with a large collar on the inner member side that contacts the large end surface of the tapered roller and guides the tapered roller. The wheel bearing device according to any one of claims 1 to 3, wherein the wheel bearing device is integrally formed on a large-diameter side of the outer rolling surface.

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