JP4993342B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that achieves higher rigidity and longer bearing life.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are 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. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. On the other hand, double row tapered roller bearings are used in vehicles such as off-road cars and trucks that have a heavy vehicle body weight.

  Further, the 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. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. 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 speed universal joint.

  In such a wheel bearing device, conventionally, both rows of bearings have the same specification, so that they have sufficient rigidity when stationary, but the optimum rigidity is not always obtained when the vehicle turns. That is, the position of the vehicle weight when stationary is determined so that it acts on the approximate center of the double row rolling bearing, but when turning, the opposite side of the turning direction (when turning right, the vehicle A large radial load or axial load is applied to the left axle. Therefore, at the time of turning, it is effective to increase the rigidity of the outer bearing row rather than the inner bearing row. Then, what is shown in FIG. 6 is known as a wheel bearing apparatus which improved the rigidity at the time of turning, without enlarging an apparatus.

  This wheel bearing device 50 has a vehicle body mounting flange 51c integrally attached to a knuckle (not shown) on the outer periphery, and an outer side in which double row outer rolling surfaces 51a and 51b are formed on the inner periphery. A member 51 and a wheel mounting flange 53 for mounting a wheel (not shown) at one end are integrally formed, and one inner rolling surface 52a facing the double row outer rolling surfaces 51a and 51b on the outer periphery. The hub wheel 52 having a small-diameter step portion 52b extending in the axial direction from the inner rolling surface 52a and the small-diameter step portion 52b of the hub wheel 52 are externally fitted to the double-row outer rolling surfaces 51a and 51b. An inner member 55 composed of an inner ring 54 formed with the other inner rolling surface 54a facing each other, double rows of balls 56, 57 accommodated between both rolling surfaces, and these double rows of balls 56, 57 A retainer 58 for freely rolling It is composed of a double row angular contact ball bearing with a 9.

  The inner ring 54 is fixed in the axial direction by a caulking portion 52c formed by plastically deforming a small diameter step portion 52b of the hub wheel 52 radially outward. Seals 60 and 61 are attached to the opening of the annular space formed between the outer member 51 and the inner member 55, leakage of the lubricating grease sealed inside the bearing, and rainwater from the outside into the bearing. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the outer side ball 56 is set larger than the pitch circle diameter D2 of the inner side ball 57. Along with this, the inner rolling surface 52a of the hub wheel 52 is expanded in diameter than the inner rolling surface 54a of the inner ring 54, and the outer rolling surface 51a on the outer side of the outer member 51 is also rolled on the inner side. The diameter is larger than that of the surface 51b. The outer side balls 56 are accommodated more than the inner side balls 57. In this way, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device 50 can be extended. it can.
JP 2004-108449 A

  However, in the case of such a conventional wheel bearing device 50, the rigidity of the inner side bearing row is insufficient with respect to the rigidity of the outer side bearing row, and the outer side of the hub wheel 52 is formed with an enlarged diameter. However, an increase in weight at least for this expanded diameter cannot be avoided, and there has been a limit to reducing the weight of the apparatus. Further, in the assembly process of the apparatus, when the ball 56 is temporarily assembled to the outer side outer rolling surface 51a of the outer member 51 via the retainer 58, the ball 56 is formed on the inner diameter of the outer rolling surface 51a counter portion. Since the ball 56 is inserted while being rubbed, a minute flaw is generated on the ball 56, which not only deteriorates the acoustic characteristics of the bearing but also may cause a short life.

  The present invention has been made in view of such circumstances, and solves the conflicting problems of light weight, compactness and high rigidity of the device, prevents the occurrence of ball scratches during assembly, and the acoustic characteristics of the bearing. An object of the present invention is to provide a bearing device for a wheel that improves the service life and extends the service life.

In order to achieve the object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member, and a wheel mounting flange for mounting a wheel at one end are integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and an axis from the inner rolling surface Hub wheel formed with a small-diameter step portion extending in the direction, and the other inner rolling surface that is press-fitted into the small-diameter step portion of the hub wheel through a predetermined shimoshiro and faces the outer rolling surface of the double row on the outer periphery In a wheel bearing device comprising: an inner member formed of an inner ring formed with an inner ring; and a double row rolling element that is slidably accommodated between both rolling surfaces of the inner member and the outer member. Out of the double row rolling elements, the outer side rolling element is a ball and the inner side rolling element. And a tapered roller, the pitch circle diameter of the tapered rollers on the inner side is set smaller in diameter than the pitch circle diameter of the outer side of the ball, Wataru from the groove bottom of the inner raceway surface of the hub wheel to the cylindrical portion A shaft-shaped portion extending in the axial direction is formed, a tapered step is formed between the shaft-shaped portion and a shoulder that is abutted against the inner ring, and the depth of the recess is The depth of the inner rolling surface extends beyond the groove bottom to the vicinity of the step portion, and the corner portion of the counter portion on the outer rolling surface on the outer side of the outer member is flattened to form a smooth arc shape. Thus, the surface roughness of the counter inner diameter is regulated to 3.2 Ra or less.

Thus, an outer member having a vehicle body mounting flange on the outer periphery, a hub wheel having a wheel mounting flange at one end, an inner member made of an inner ring press-fitted into the hub wheel, and the inner member and the outer member. In a third-generation wheel bearing device comprising a double row rolling element housed between members, the outer side rolling element of the double row rolling element is a ball and the inner side rolling element is a tapered roller. Yes, the pitch circle diameter of the inner side tapered roller is set smaller than the pitch circle diameter of the outer side ball, and extends in the axial direction from the groove bottom of the inner raceway surface of the hub wheel to the small diameter step. A shaft-shaped portion is formed, a tapered step is formed between the shaft-shaped portion and the shoulder that is abutted against the inner ring, and the depth of the recess exceeds the groove bottom of the inner rolling surface. is the depth to the vicinity of the step portion, and, outside the outer side of the outer member The corners of the counter section on the rolling surface are flattened to form a smooth arc shape, and the surface roughness of the counter inner diameter is regulated to 3.2 Ra or less, making the device lighter, more compact and more rigid. In addition to solving the conflicting problems, it is possible to provide a wheel bearing device that can suppress ball contact scratches and ball damage due to ball vibration during assembly, and improve the acoustic characteristics of the bearing.

  Preferably, as in the invention described in claim 2, if the counter part of each rolling surface and the corner part of the groove shoulder part in the outer side bearing row are flattened and formed into a smooth arc shape. In addition to preventing the occurrence of ball scratches during assembly, the acoustic characteristics of the bearings are improved, and even if contact ellipses due to contact between the rolling surfaces and the balls hit the groove shoulders, edge load is prevented from occurring. Thus, the life of the bearing can be extended.

  Further, as in the invention according to claim 3, the counter part, groove shoulder part and counter inner diameter of each rolling surface in the outer side bearing row are formed by simultaneous grinding with the rolling surface by a general-purpose grindstone after heat treatment. If so, the surface can be formed more smoothly.

According to a fourth aspect of the present invention, in the axial direction, the inner ring is applied with a predetermined preload by a crimped portion formed by plastically deforming an end portion of the small-diameter stepped portion radially outward. If it is fixed to, it is possible to further reduce the weight and size, and to maintain the preload set at the initial stage over a long period of time.

The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange to be attached to the knuckle on the outer periphery, a double row outer rolling surface formed on the inner periphery, and a wheel at one end. A wheel mounting flange is integrally formed, and one inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery, and a small diameter step portion extending in the axial direction from the inner rolling surface is formed. And an inner ring formed by press-fitting the hub wheel into a small-diameter step portion of the hub ring via a predetermined scissors and having the other inner rolling surface facing the outer rolling surface of the double row formed on the outer periphery. In a wheel bearing device comprising a member and a double row rolling element that is rotatably accommodated between both rolling surfaces of the inner member and the outer member, an outer of the double row rolling elements is provided. The rolling elements on the side are balls, and the rolling elements on the inner side are tapered rollers. Pitch circle diameter of the tapered roller in the over side is set smaller in diameter than the pitch circle diameter of the outer side of the ball, extending axially over the cylindrical portion from the groove bottom of the inner raceway surface of the hub wheel A shaft-shaped portion is formed, a tapered step portion is formed between the shaft-shaped portion and a shoulder portion that is abutted against the inner ring, and the depth of the recess is a groove on the inner rolling surface. The depth is close to the stepped portion beyond the bottom, and the corner of the counter portion on the outer rolling surface on the outer side of the outer member is flattened to form a smooth arc, Since the surface roughness is regulated to 3.2Ra or less, it solves the conflicting issues of lighter, more compact and higher rigidity of the device, and suppresses ball contact scratches during assembly and ball damage caused by ball vibration. To improve the acoustic characteristics of the bearing. It is possible to provide a wheel bearing device.

A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member consisting of an inner ring that is press-fitted into a stepped portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member A plurality of balls that are rotatably accommodated between the surfaces, and the inner ring is pivoted with respect to the hub ring by a caulking portion formed by plastically deforming an end of the small diameter step portion radially outward. In the wheel bearing device fixed in the direction, the outer side rolling of the double row rolling elements But the ball, and the rolling elements of the inner side tapered rollers, the pitch circle diameter of the tapered rollers on the inner side is set smaller in diameter than the pitch circle diameter of the outer side of the ball, the inner raceway surface of the hub wheel A shaft-like portion extending in the axial direction from the groove bottom portion to the small-diameter step portion is formed, and a tapered step portion is formed between the shaft-like portion and a shoulder portion that abuts against the inner ring, The depth of the recess is the depth from the groove bottom of the inner rolling surface to the vicinity of the stepped portion, and the corners of the counter portion and the counter on the outer rolling surface on the outer side of the outer member The inner diameter is processed by simultaneous grinding with the rolling surface by a grinding wheel after heat treatment, the corners are flattened to form a smooth arc shape, and the surface roughness of the counter inner diameter is regulated to 3.2 Ra or less. Has been.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged view of a main part showing a bearing row on the outer side of FIG. 1, and FIG. 3 is an explanation showing an assembled state. FIG. 4 (a) is an explanatory view showing grinding of the inner rolling surface on the outer side of the hub wheel, and FIG. 4 (b) is an explanatory view showing grinding of the outer rolling surface of the outer member, FIG. These are explanatory drawings which show the ball temporary assembly to an outward member. 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 is for a driven wheel called the third generation, and includes an inner member 1 and an outer member 2, and a plurality of balls 3 accommodated so as to roll between both members 1 and 2. A tapered roller 4 is provided. The inner member 1 includes a hub ring 5 and an inner ring 6 press-fitted into the hub ring 5 through a predetermined shimiro.

  The hub wheel 5 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at one end portion, one (outer side) arcuate inner rolling surface 5a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 5a. Hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially uniform manner, and circular holes 7b are formed between the hub bolts 7a. The circular hole 7b not only contributes to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 7b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 6 is formed with the other (inner side) tapered inner rolling surface 6a on the outer periphery, a large collar 6b for guiding the tapered roller 4 to the large diameter side of the inner rolling surface 6a, and a small diameter side In addition, a small scissors 6c for preventing the tapered roller 4 from falling off is formed. The inner ring 6 is press-fitted into the small-diameter step portion 5b of the hub wheel 5 through a predetermined shimiro, and a predetermined preload is applied by a crimping portion 9 formed by plastically deforming an end portion of the small-diameter step portion 5b. In the applied state, it is fixed in the axial direction. As a result, it is possible to reduce the weight and size, and to maintain the initially set preload over a long period of time.

  The hub wheel 5 is formed of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and includes an inner rolling surface 5a and an inner side of a wheel mounting flange 7 on which an outer seal 12 described later is in sliding contact. The surface hardness is hardened in the range of 58 to 64 HRC by induction hardening from the base 7c to the small diameter step 5b. The caulking portion 9 is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 7, and the fretting resistance of the small-diameter step portion 5 b serving as the fitting portion of the inner ring 6 is improved, and caulking is performed. There is no generation of minute cracks or the like during processing, and the plastic processing of the crimped portion 9 can be performed smoothly. The inner ring 6, the ball 3 and the tapered roller 4 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64HRC to the core by quenching.

  The outer member 2 integrally has a vehicle body mounting flange 2c to be attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and an outer member facing the inner rolling surface 4a of the hub wheel 4 on the inner periphery. An arcuate outer rolling surface 2a on the side and an inner tapered outer rolling surface 2b facing the inner rolling surface 5a of the inner ring 5 are integrally formed. This outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured. And the some ball | bowl 3 and the tapered roller 4 are accommodated rotatably via the holder | retainer 10 and 11 between both rolling surface 2a, 4a and 2b, 5a. In addition, a seal 12 and a magnetic encoder 13 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing to the outside Prevents rainwater and dust from entering the bearing.

  In the present embodiment, the pitch circle diameter PCDi of the four rows of inner side tapered rollers is set to be smaller than the pitch circle diameter PCDo of the three rows of balls on the outer side. As a result, the outer diameter D on the inner side of the outer member 2 can be set to a small diameter. By using the tapered rollers 4, the knuckle size can be reduced without reducing the basic load rating of the inner rolling element row. The rigidity of the rolling element row portion on the inner side is increased while reducing the size and weight of the device.

  A mortar-shaped recess 14 is formed at the outer end of the hub wheel 5 in the forging process in order to reduce the weight (indicated by a two-dot chain line), and is formed deeper in the axial direction than the recess 14. A recess 15 is formed. The depth of the recess 15 is set to a depth from the inner rolling surface 5a to the vicinity of the stepped portion 21 beyond the groove bottom. The outer shape of the hub wheel 5 is a small diameter step through a shaft portion 8 extending in the axial direction from the groove bottom portion of the inner rolling surface 5a, a tapered step portion 8a, and a shoulder portion 8b against which the inner ring 6 is abutted. Following the portion 5 b, the thickness is formed to be uniform corresponding to the recess 15.

  On the other hand, in the outer member 2, with the difference in pitch circle diameters PCDo and PCDi, the outer-side outer rolling surface 2a has a diameter larger than the inner-side outer rolling surface 2b, and the outer-side outer rolling surface 2a. From the shoulder 17 on the small diameter side through the cylindrical shoulder 16 and the stepped portion 16a to the outer rolling surface 2b on the inner side.

  Here, the corner portions of the counter portions A and B and the groove shoulder portions C and D of the rolling surfaces 5a and 2a in the three rows of balls on the outer side are flattened to form a smooth arc shape. Specifically, as shown in an enlarged view in FIG. 2, a counter portion A having a larger diameter than the groove bottom diameter and a predetermined width is formed in the vicinity of the groove bottom portion of the inner rolling surface 5a. The counter portion A is formed in a smooth arc shape having an angular radius R of 1.0 to 5R. Further, the chamfered axial dimension La at the corners of the counter part B and the groove shoulder parts C and D is 0.15 to 0.8 mm, preferably 0.15 to 0.3 mm, and the radial dimension Lr is 0.15. -0.8 mm, preferably 0.15 to 0.3 mm, and the corner radius R is set to 0.15 to 2.0 R, preferably 0.45 to 0.7 R. Each connecting portion is formed smoothly. If the corner radius R is less than 0.15R, the ball 3 is easily scratched. On the other hand, if the corner radius R exceeds 2.0R, the contact ellipse of the ball 3 is formed at the groove shoulders C and D. Is undesirably easy to get on and disengage from the inner rolling surface 4a.

  As described above, the counter portions A and B and the shoulder portions C and D of the rolling surfaces 5a and 2a in the three rows of balls on the outer side are formed in a smooth arc shape having a predetermined angle R. In the assembly of the bearing as shown in FIG. 3, it is possible to prevent the ball 3 from being damaged even if the outer ball 3 comes into contact with the counter parts A and B and the shoulder parts C and D. In addition to improving the characteristics, when the seal 12 is mounted, it is possible to prevent the lip from being damaged even if it is extrapolated in contact with the corner portion C, and to improve the reliability of the quality and the sealing performance. Can do. In addition, when a large moment load is applied to the apparatus, it is possible to prevent the occurrence of edge load even if the contact ellipse due to the contact between the inner rolling surface 5a and the ball 3 hits the shoulders C and D, The life of the bearing can be extended.

  As shown in FIG. 4, these counter portions A and B and shoulder portions C and D are ground simultaneously with the rolling surfaces 5a and 2a by a general-purpose grindstone after heat treatment. That is, as shown in FIG. 4A, the base portion 7c and the inner rolling surface 5a of the wheel mounting flange 7 serving as the seal land portion are formed by being integrally ground by the general-purpose grindstone 18, The counter part A and the groove shoulder C are also ground simultaneously by the total-type grindstone 18. By simultaneously grinding the counter part A with the inner rolling surface 5a, it is possible to prevent the occurrence of burrs and the like, and it is possible to form the outer diameter of the counter part A with high accuracy without variation.

  Further, as shown in FIG. 4 (b), the double row outer rolling surfaces 2a, 2b of the outer member 2 are formed by being integrally ground by a general-purpose grindstone 19, but at this time, the groove shoulder portion D and the counter part B are also simultaneously ground by this general-purpose grindstone 19. Here, the counter inner diameter 20 and the seal fitting surface 21 to which the seal 12 is mounted are also ground and the surface roughness is regulated to 3.2 Ra or less. Ra is one of JIS roughness shape parameters (JIS B0601-1994), and is an arithmetic average roughness, that is, an average value of absolute value deviation from an average line. By regulating the surface roughness of the counter inner diameter 20 in this manner, as shown in FIG. 5, when the ball 3 is temporarily assembled on the outer rolling surface 2a on the outer side, the ball 3 is counter of the outer rolling surface 2a. Even if it is inserted while being rubbed against the inner diameter 20, it is not transferred and scratched on the surface of the ball 3, and even if the ball 3 comes into contact with the corner of the counter portion B, it can be prevented from being scratched. .

  Here, the counter inner diameter 20 is illustrated as being simultaneously ground by the outer rolling surface 2a and the total-type grindstone. However, the invention is not limited to this, and the counter inner diameter 20 may be formed by turning in advance. In this case, if the turning line is a lead line or a crossing line, there is a possibility that the turning line is transferred to the ball 3. Therefore, turning by plunge cutting is preferable instead of traverse processing. Table 1 shows the relationship between the surface roughness of the counter inner diameter 20 and the flaw depth in the ball 3 with respect to the bite feed speed. As is apparent from this table, even when traversing, Feed is 0.2 mm / rev. By processing at a slower rate below, the surface roughness of the counter inner diameter 20 can be improved to 3.3 Ra or less, and the occurrence of scratches on the ball 3 can be prevented.

  As described above, in this embodiment, the counter parts A and B and the groove shoulders C and D of the rolling surfaces in the outer side bearing row are simultaneously ground by the grinding wheels 18 and 19 together with the rolling surfaces 5a and 2a. In addition, the corners are flattened and formed into a smooth arc shape, and the counter inner diameter 20 is regulated to a predetermined surface roughness or less, so that the contact between the rolling surfaces 5a and 2a and the balls 3 Even if the contact ellipse is applied to the groove shoulders C and D, it is possible to suppress the occurrence of edge load, and it is possible not only to extend the life of the bearing, but also due to ball contact damage or ball damage during assembly. Etc. can be prevented, and the acoustic characteristics of the bearing can be improved.

  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 third generation structure regardless of whether it is for driving wheels or driven wheels.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a principal part enlarged view which shows the outer side bearing row | line | column of FIG. It is explanatory drawing which shows an assembly state same as the above. (A) is explanatory drawing which shows the grinding process of a hub ring. (B) is explanatory drawing which shows the grinding process of an outer member. It is explanatory drawing which shows the ball | bowl temporary assembly to an outward member. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1 ... Inner member 2 ... Outer member 3 ... ·········· Ball 4 ····································································・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 5b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 6 ・ ・ ・ ・ ・ ・ ・ ・・ Inner ring 6b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Omine 6c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Kominato 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Wheel mounting flange 7a ... Hub bolt 7b ... Round hole 7c ... ············································· Shaft-shaped portion 8a, 16a ...・····················· 9・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Seal 13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Magnetic encoder 14, 15 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Concave Locations 16, 17, C, D ... Groove shoulders 18, 19 ... Total grinding wheel 20 ... ... Counter inner diameter 21 ... Seal fitting surface 50 ... Wheel bearing device 51 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer member 51a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51b on the outer side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Outer rolling surface 51c on the inner side ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 52 ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheels 52a, 54a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 52b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 52c ············································… .... Inner ring 55 ... Inner members 56, 57 ... Balls 58, 59 ... ... Retainer 60, 61 ... Seal A, B ... Counter D1 ...・ ・ ・ ・ ・ ・ Pitch circle diameter D2 of outer side ball ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter La of inner side ball ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Chamfer axial dimension Lr ...・ Chamfer radial dimension PCDo ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of outer side ball PCDi ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of inner side ball R ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Square Earl

Claims (4)

An outer member integrally having a vehicle body mounting flange to be attached to the knuckle on the outer periphery, and a double row outer rolling surface formed on the inner periphery;
A wheel mounting flange for mounting a wheel at one end is integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface A hub ring formed with a portion, and an inner ring that is press-fitted into a small-diameter step portion of the hub ring through a predetermined squeeze and has the other inner rolling surface opposed to the double-row outer rolling surface on the outer periphery. An inner member comprising:
In the wheel bearing device including the inner member and a double-row rolling element that is accommodated in a freely rolling manner between both rolling surfaces of the outer member,
Out of the double row rolling elements, the outer side rolling element is a ball and the inner side rolling element is a tapered roller, and the pitch circle diameter of the inner side tapered roller is smaller than the pitch circle diameter of the outer side ball. A shaft-shaped portion extending in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small-diameter step portion is formed, and the shaft-shaped portion and a shoulder portion that abuts against the inner ring A tapered step is formed between the recesses, and the depth of the recess extends beyond the groove bottom of the inner rolling surface to the vicinity of the step, and the outer side of the outer member The wheel bearing device is characterized in that the corner of the counter portion on the outer rolling surface of the wheel is flattened to form a smooth arc shape, and the surface roughness of the counter inner diameter is regulated to 3.2 Ra or less. .   2. The wheel bearing device according to claim 1, wherein the counter portion of each rolling surface and the corner portion of the groove shoulder portion in the outer side bearing row are flattened to form a smooth arc shape.   3. The wheel according to claim 1, wherein the counter part, the groove shoulder part, and the counter inner diameter of each rolling surface in the outer side bearing row are formed by simultaneous grinding with the rolling surface by a general-purpose grindstone after heat treatment. Bearing device. The wheel according to claim 1, wherein the inner ring is fixed in the axial direction in a state where a predetermined preload is applied by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward. Bearing device.

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