JP2007032847A - Manufacturing method of wheel supporting hub unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of damage such as a crack to a caulking part 16 for pressing down an inner ring 3 to a shaft member 2. <P>SOLUTION: The caulking part 16 is formed by performing plastic deformation of a cylindrical part formed at the inner end of the shaft member 2 and reduced in wall thickness toward the tip, so as to be enlarged diametrically outward. Force required for forming the caulking part 16 is reduced to hardly cause the damage, and the bearing power of the inner ring 3 by the caulking part 16 is secured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The wheel support hub unit according to the present invention is used for rotatably supporting the wheel of an automobile with respect to a suspension device.

  The wheels of the automobile are supported on the suspension device by a wheel supporting hub unit. FIG. 8 shows an example of a wheel supporting hub unit that has been widely used in the past. The wheel support hub unit 1 includes a shaft member 2, an inner ring 3, an outer ring 4, and a plurality of rolling elements 5 and 5. Of these, the outer end of the outer peripheral surface of the shaft member 2 (outside means the side that is outside in the width direction when assembled to the automobile, and is the left side of each figure excluding FIG. 4. A flange (first flange) 6 for supporting a wheel is formed on the side closer to the inner side, which is the right side of each drawing except FIG. Further, a first inner ring raceway 7 is formed at an intermediate portion of the shaft member 2, and a step portion 8 having a smaller outer diameter is formed at the inner end portion. The first inner ring raceway 7 may be formed directly on the outer peripheral surface of the intermediate portion of the shaft member 2 or may be formed on the outer peripheral surface of the inner ring fitted on the intermediate portion of the shaft member 2 (the present invention). (Refer to the hatched portion by the chain line in FIGS. 1, 5, 6, and 7). In this case, the stepped portion 8 is a portion separated from the inner ring 3 at the end of the shaft member 2.

  In any case, an inner ring 3 having a second inner ring raceway 9 formed on the outer peripheral surface is externally fitted to the stepped portion 8. A male screw portion 10 is formed at the inner end portion of the shaft member 2, and the tip end portion of the male screw portion 10 protrudes inward from the inner end surface of the inner ring 3. Then, the inner ring 3 is clamped and fixed to a predetermined position of the shaft member 2 by sandwiching the inner ring 3 between the nut 11 screwed into the male threaded portion 10 and the stepped surface 12 of the stepped portion 8. Yes. A locking recess 17 is formed on the outer peripheral surface of the distal end portion of the male screw portion 10. Then, after tightening the nut 11 with a predetermined torque, a portion of the nut 11 that is aligned with the recess 17 is caulked inward in the diametrical direction to prevent the nut 11 from loosening.

  A first outer ring raceway 13 facing the first inner ring raceway 7 and a second outer ring raceway 14 facing the second inner ring raceway 9 are formed on the inner peripheral surface of the outer ring 4. . A plurality of rolling elements 5 and 5 are provided between the first and second inner ring raceways 7 and 9 and the first and second outer ring raceways 13 and 14, respectively. In the illustrated example, balls are used as the rolling elements 5 and 5. However, in the case of a heavy vehicle hub unit, tapered rollers may be used as these rolling elements.

  In order to assemble the wheel support hub unit 1 as described above to an automobile, the outer ring 4 is fixed to the suspension device by an outward flange-like mounting portion (second flange) 15 formed on the outer peripheral surface of the outer ring 4. The wheel is fixed to the flange 6. As a result, this wheel can be rotatably supported with respect to the suspension device.

  Patent Document 1 describes a wheel support hub unit 1 having a structure as shown in FIG. In the case of the second example of this conventional structure, a caulking portion 16 is formed by bending a portion protruding inward from the inner end surface of the inner ring 3 at the inner end portion of the shaft member 2 outward in the diameter direction. The inner ring 3 is sandwiched between the caulking portion 16 and the step surface 12 of the step portion 8. That is, the caulking portion 16 is formed by caulking the cylindrical portion formed at the inner end portion of the shaft member 2 at the portion protruding inward from the inner ring 3 in the diametrically outward direction. The inner ring 3 is pressed against the step surface 12 (outer end surface) of the step portion 8.

  In the case of the first example of the conventional structure shown in FIG. 8, it is necessary to perform an operation of forming the locking recess 17 at the tip of the male screw portion 10 and an operation of caulking a part of the nut 11 inward in the diameter direction. Become. For this reason, the parts manufacturing work and assembling work of the wheel supporting hub unit 1 become troublesome, and the cost increases.

  Further, in the case of the structure of the second example shown in FIG. 9, when the caulking portion 16 for fixing the inner ring 3 to the shaft member 2 is formed, the caulking portion 16 is easily damaged such as a crack. Instead, a force directed outward in the diameter direction is applied to the inner peripheral surface of the inner ring 3 adjacent to the caulking portion 16. That is, in the case of the conventional structure, in order to form the caulking portion 16, both the inner and outer peripheral surfaces of the cylindrical portion formed at the inner end portion of the shaft member 2 are simple cylindrical surfaces that are concentric with each other. The wall thickness was the same over the entire length. For this reason, a large force is required when the inner end portion of the cylindrical portion is caulked and expanded to form the caulking portion 16, and not only the caulking operation is troublesome, but also the leading edge of the caulking portion 16 is accompanied by caulking. The above-described damage is likely to occur due to a large tensile stress.

  In addition, the force applied to the inner peripheral surface of the inner ring 3 is increased by the amount of large force applied during the caulking work, and the diameter of the inner ring 3 changes, albeit slightly. When the amount of change increases, not only the inner ring 3 may be damaged such as cracks, but also the diameter and shape accuracy of the second inner ring raceway 9 formed on the outer peripheral surface of the inner ring 3 (roundness) Degree, cross-sectional shape) deteriorates. And the operation | work which maintains the preload provided to the rolling elements 5 and 5 to an appropriate value becomes troublesome, and it may become difficult to ensure durability.

US Pat. No. 5,226,738

  In view of the circumstances as described above, the wheel support hub unit of the present invention can omit the operation of forming a locking recess and the operation of caulking the nut to prevent the nut fixing the inner ring to the shaft member. The structure prevents the caulking portion 16 from being damaged such as cracks during the fixing operation of the inner ring 3, and the second inner ring raceway formed on the inner diameter of the inner ring 3 and the outer peripheral surface of the inner ring 3 along with the caulking operation. The diameter of 9 is not changed so as to cause a practical problem.

  As in the second example of the conventional wheel support hub unit shown in FIG. 9, the wheel support hub unit of the present invention includes a shaft member in which a first flange is formed on the outer peripheral surface of one end, A first inner ring raceway formed on the outer peripheral surface of the intermediate portion directly or via an inner ring separate from the shaft member and the first inner ring raceway formed on the other end of the shaft member were formed. A step portion having a smaller outer diameter than the portion, an inner ring formed on the outer peripheral surface of the second inner ring raceway and fitted on the stepped portion, and an inner peripheral surface facing the first inner ring raceway. A first outer ring raceway and a second outer ring raceway opposed to the second inner ring raceway, an outer ring formed with a second flange on the outer peripheral surface, the first and second inner ring raceways and the first And a plurality of rolling elements each provided between the second outer ring raceway and the second outer ring raceway. The cylindrical member formed at the other end of the shaft member at least in a portion projecting from the inner ring fitted on the stepped portion is squeezed outwardly in the diametrical direction, and is externally attached to the stepped portion. The fitted inner ring is pressed against the end surface of the stepped portion, and the inner ring fitted on the stepped portion is coupled and fixed to the shaft member.

  In particular, in the wheel support hub unit of the present invention, the thickness of the cylindrical portion is smaller toward the tip edge in a state before the cylindrical portion is caulked outward in the diameter direction, and The cylindrical portion is formed by caulking outward in the diametrical direction, and the thickness of the caulking portion that suppresses the end face of the inner ring that is externally fitted to the stepped portion decreases toward the tip.

The operation of rotatably supporting the wheel with respect to the suspension device by the wheel supporting hub unit of the present invention configured as described above is the same as that of the conventional wheel supporting hub unit.
In particular, in the case of the wheel support hub unit of the present invention, since the thickness of the cylindrical portion for forming the caulking portion is reduced toward the leading edge, the force required to form the caulking portion is increased. It ’s never going to grow. For this reason, damage such as cracks occurs in the caulking part during caulking work, or the inner ring diameter is large enough to affect the durability such as preload and rolling fatigue life of the inner ring fixed by the caulking part. There is no power to change.
In this way, it is possible to prevent the caulking portion from being damaged, such as a crack, and to prevent the caulking portion from changing so that the diameter of the inner ring fixed to the shaft member becomes a practical problem. Further, it is possible to reduce the possibility that the inner ring is damaged based on the fixing operation and to maintain the preload at an appropriate value, and to reduce the cost by reducing the number of parts, parts processing, and assembly man-hours.

[First example of embodiment]
1 to 4 show a first example of an embodiment of the present invention. The feature of the present invention lies in the structure of the portion for fixing the inner ring 3 to the shaft member 2. Since the structure and operation of other parts are the same as those of the conventional structure shown in FIG. 9 described above, the overlapping description will be omitted or simplified, and the following description will focus on the characteristic parts of the present invention.

  The thickness of the cylindrical portion 18 for forming the caulking portion 16 for fixing the inner ring 3 formed on the inner end portion of the shaft member 2 is shown in FIG. It is in a state before it spreads toward the end, and it becomes smaller toward the tip edge. For this reason, in the illustrated example, a tapered hole 19 is formed on the inner end surface of the shaft member 2 so that the inner diameter gradually decreases toward the recess.

  In order to squeeze the tip of the cylindrical portion 18 as described above in order to fix the inner ring 3 to the inner end of the shaft member 2, the shaft member 2 is fixed so as not to move in the axial direction. As shown in FIG. 2, the pressing die 20 is strongly pressed against the tip of the cylindrical portion 18. A frustoconical convex portion 21 that can be pushed into the inside of the cylindrical portion 18 is formed at the center of the tip surface (left end surface in FIG. 2) of the pressing die 20, and a circular arc section is formed around the convex portion 21. The concave portion 22 is formed so as to surround the entire circumference of the convex portion 21.

The cross-sectional shape of the recess 22, the outer diameter R ₂₂ and the depth D ₂₂ are determined by the metal (steel) constituting the cylindrical portion 18 when the cylindrical portion 18 is plastically deformed to form the caulked portion 16. ) Is applied so as to form the caulking portion 16 having a predetermined shape and size. That is, the cross-sectional shape of the concave portion 22 is such that the cross-sectional shape of the caulking portion 16 obtained by plastically deforming the distal end portion of the cylindrical portion 18 by the concave portion 22 has a thickness dimension toward the distal end portion from the proximal end portion. The composite curved surface has a curvature radius that becomes smaller toward the outer diameter side, so that the thickness dimension is abruptly reduced especially at the tip portion so as to gradually become smaller. The outer diameter R ₂₂ are the same as the outer diameter R ₁₆ to be formed caulking portions 16, and the degree slightly smaller (R ₂₂ ≦ R ₁₆₎ than the outer diameter R ₁₆ of the crimped portion 16. Further, the depth D ₂₂ is the tip end of the pressing die 20 in a state where the end portion of the cylindrical portion 18 is sandwiched between the inner peripheral surface and the inner end surface of the inner end portion of the inner ring 3 to form the caulking portion 16. The gap 23 is restricted to remain between the surface and the inner end surface of the inner ring 3.

  If the pressing die 20 having the convex portion 21 and the concave portion 22 having the shape and dimensions as described above is pressed against the tip portion of the cylindrical portion 18, the tip portion of the cylindrical portion 18 is caulked outward in the diametrical direction, The caulking portion 16 can be formed. The inner ring 3 can be clamped between the caulking portion 16 and the step surface 12 of the step portion 8 formed at the inner end of the shaft member 2, and the inner ring 3 can be fixed to the shaft member 2. In the case of the illustrated example, in the final stage of forming the caulking portion 16 by plastically deforming the inner end surface of the cylindrical portion 18, the inner surface of the concave portion 22 extends from the inner surface of the caulking portion 16 in the diametrical direction. Inward compression force acts. Therefore, it is possible to effectively prevent the occurrence of damage such as cracks on the outer peripheral edge of the caulking portion 16. Further, a curved surface portion 24 having an arcuate cross section is formed at the peripheral edge of the inner end opening of the inner ring 3 where the outer diameter surface of the base end portion of the caulking portion 16 contacts. Therefore, the radius of curvature of the base end portion of the caulking portion 16 does not become small, and it is difficult to apply excessive stress to the base end portion.

  As described above, in the case of the wheel supporting hub unit of the present invention, the thickness of the cylindrical portion 18 for forming the caulking portion 16 is reduced toward the distal end edge. The force required to form the caulking portion 16 by plastically deforming with the above-described pressing mold 20 does not increase. For this reason, damage such as cracks occurs in the caulking portion 16 during the caulking work, or the inner ring 3 is fixed to the inner ring 3 by the caulking portion 16, and the diameter of the inner ring 3 affects the durability such as preload and rolling fatigue life. The force which changes so much that it exerts does not act. In particular, in the illustrated example, compressive stress is applied to the distal end portion of the caulking portion 16 and the radius of curvature of the base end portion of the caulking portion 16 is increased, so that the caulking portion 16 can be more effectively prevented from being damaged. I can plan. In FIG. 1, reference numeral 25 denotes a seal ring for preventing dust from entering the space provided with the rolling elements 5, 5 or leakage of lubricating oil from this space, and 26 is an inner ring of the outer ring 4. It is a lid that closes the end opening.

Next, the appropriate values of the dimensions of each part in the case of realizing the structure as shown in FIGS. In the case of a wheel supporting hub unit incorporated in a general passenger car, this value is the inner diameter r ₃ of the inner ring 3 to be fixed to the shaft member 2 is about 20 to 60 mm, and the length dimension L ₃ is 15 to 15 mm. In the case of about 40 mm, the shaft member 2 is made of structural carbon steel of about S53C, and the inner ring 3 is made of bearing steel such as SUJ2.
First, the thickness t ₁₈ of the tip of the cylindrical portion 18 before the caulking portion 16 is processed is preferably in the range of 1.5 to 5 mm. The thickness T ₁₈ of the base end portion of the cylindrical portion 18 is preferably in the range of 5 to 10 mm. If the thickness dimensions t ₁₈ and T ₁₈ of the distal end portion and the proximal end portion are regulated within this range, the caulking portion 16 is prevented from being damaged such as cracks, and the inner ring 3 by the caulking portion 16 is prevented. Support rigidity can be secured.
That is, it is possible to effectively prevent the occurrence of the damage by reducing the thickness of the tip of the cylindrical portion 18 where the amount of deformation increases and making the tip easily plastically deformable. Also, the base end portion of the cylindrical portion 18 that is used to hold the inner ring 3 toward the stepped surface 12 can be made thick so that the support strength of the inner ring 3 can be sufficiently secured.

The length L ₁₈ of the cylindrical portion 18 is preferably about 8 to 20 mm. If the length L ₁₈ is too small (L ₁₈ <8 mm), the caulking portion 16 cannot be formed sufficiently, or damage such as cracks is likely to occur in a part of the caulking portion 16 during formation. On the other hand, if the length L ₁₈ is too large (L ₁₈ > 20 mm), the length of the hollow portion existing at the inner end of the shaft member 2 becomes too long, and the strength of the shaft member 2 is increased. And the inner end portion of the shaft member 2 is easily deformed based on the radial load applied to the inner ring 3. The operation of plastically deforming the cylindrical portion 18 restricted to the dimensions as described above to form the caulking portion 16 is preferably performed by forging or swing pressing.

  Further, the line of action of the load applied to the inner ring 3 from the plurality of rolling elements 5 (corresponding to the chain line α in FIG. 2 representing the contact angle of the rolling elements 5) is the inner peripheral surface of the inner ring 3 and the step portion 8. So that it does not pass through the crimping portion 16. The reason for this restriction is to prevent the caulking portion 16 from being damaged by preventing the load from acting as a force that directly deforms the caulking portion 16 inward in the diameter direction.

Next, in the inner ring 3, a cross-sectional area S ₃ of a portion closer to the outer side than the second inner ring raceway 9 (A-A line portion in FIG. 3) and a cross-sectional area S ₂ of the shaft member 2 in the portion. , S ₃ <S ₂ , more preferably S ₃ ≦ 0.94 S ₂ . The reason for restricting the cross-sectional areas of these parts in this way is to ensure the support strength of the inner ring 3 with respect to the shaft member 2.

That is, in a state where the inner ring 3 is sandwiched between the caulking portion 16 and the stepped surface 12, the force (axial force) for preventing the inner ring 3 from rotating by pressing the inner ring 3 in the axial direction is It is determined by the difference in distortion amount in the axial direction of the shaft member 2 and the inner ring 3. That is, during the caulking process, the elastic deformation amount of the inner ring 3 is larger than the elastic deformation amount of the shaft member 2. After the caulking process is completed, the inner ring 3 and the shaft member 2 are elastically restored, and an axial force (axial force) is applied to the inner ring 3. The material constituting the inner ring 3 and the material constituting the shaft member 2 have substantially the same elastic modulus. Therefore, if S ₃ <S _{2 as} described above, the amount of elastic deformation during the caulking process is as follows. The inner ring 3 is larger than the inner ring 3. Therefore, if the cross-sectional areas of the respective parts are regulated in this way, it is possible to effectively prevent the occurrence of so-called creep in which the inner ring 3 continues to be applied to the inner ring 3 and the inner ring 3 rotates with respect to the shaft member 2. .

Next, when the plurality of rolling elements 5 arranged around the inner ring 3 are balls, the distance L _O3 from the center O of the rolling element 5 to the inner end face of the inner ring 3 is the diameter D ₅ of the rolling element 5. 0.75 times or more (L _O3 ≧ 0.75D ₅ ) is preferable. The reason why the distance L _O3 is ensured to some extent is that the diameter of the second inner ring raceway 9 portion with which the rolling surface of the rolling element 5 abuts increases as the caulking portion 16 is formed. This is to prevent the accuracy (roundness, cross-sectional shape) from deteriorating. That is, if the distance L _O3 is too small, the base end portion of the caulking portion 16 is present on the inner diameter side portion of the second inner ring raceway 9, and the above-described caulking portion 16 is formed. There is a possibility that the diameter of the second inner ring raceway 9 portion becomes so large that it cannot be ignored or the accuracy is deteriorated.

Next, the outer diameter R ₁₆ of the crimped portion 16 described above, the relationship between the inner diameter r ₃ of the inner ring 3, an outer diameter R ₃ of the portion deviated from the second inner ring raceway 9 to the outer ends of the inner ring 3 Therefore, it is preferable to regulate to the following range.
r ₃ +0.7 (R ₃ −r ₃ ) ≦ R ₁₆ ≦ r ₃ +1.3 (R ₃ −r ₃ )
By regulating the outer diameter R ₁₆ of the crimped portion 16 in this range, and prevent the damage such as cracks to the caulking portion 16 is generated, and, ensuring support strength of the inner ring 3 with respect to the shaft member 2 it can.
When the outer diameter R ₁₆ is shifted in a direction larger than the above range, the damage is likely to occur. On the other hand, if the outer diameter R ₁₆ is shifted in a direction smaller than the above range, it is difficult to ensure the support strength.

Furthermore, the cross-sectional shape of the curved surface portion 24 is preferably regulated as follows. First, an inclined surface portion is provided near the starting point of the curved surface portion 24, and an angle θ _{24 at} which the inclined surface portion is inclined with respect to the central axis of the inner ring 3 is set to 10 to 45 degrees. The curvature radius r ₂₄ of the portion where the inner peripheral surface of the inner ring 3 and the inclined surface portion are continuous is set to 2 to 8 mm. Further, the curvature radius R ₂₄ of the portion where the inclined surface portion and the end surface of the inner ring 3 are continuous is set to 3 to 10 mm.

  By regulating the cross-sectional shape of the curved surface portion 24 in this manner, excessive stress is generated at the proximal end portion of the caulking portion 16 when the cylindrical portion 18 is plastically deformed to form the caulking portion 16. This prevents the damage to the base end portion.

[Second Example of Embodiment]
Next, FIG. 5 shows a second example of the embodiment of the present invention. In this example, the present invention is applied to a wheel support hub unit with a rotation speed detection device for detecting the rotation speed of a wheel. For this reason, in the case of this example, a step portion 31 having a smaller diameter than the shoulder portion 27 of the inner ring 3 and projecting inward from the shoulder portion 27 is formed at the inner end portion of the inner ring 3. And the base end part (left end part of FIG. 5) of the tone wheel 28 which comprises a rotational speed detection apparatus is externally fixed to this shoulder part 27. A part of the tone wheel 28 abuts on the outer end surface of the shoulder 27 against the peripheral portion of the base end portion of the stepped portion 31 to achieve positioning in the axial direction (left-right direction in FIG. 5). Further, a synthetic resin cover 29 is fitted and fixed to the inner end opening of the outer ring 4, and a sensor 30 embedded in the cover 29 is opposed to the tone wheel 28 to constitute a rotational speed detection device. ing.

In the case of this example, the step portion 31 is formed at the inner end portion of the inner ring 3 as described above, and the step portion 31 is suppressed by the caulking portion 16 formed at the inner end portion of the shaft member 2. The axial distance between the caulking portion 16 and the second inner ring raceway 9 formed on the outer peripheral surface of the inner ring 3 is increased by the amount of the step portion 31 formed. As a result, the dimensional change of the second inner ring raceway 9 due to the formation of the caulking portion 16 can be further suppressed. Furthermore, it is possible to prevent an increase in the outer diameter of the shoulder portion 27 as well as the second inner ring raceway 9 portion. Therefore, it is possible to prevent the function of the seal ring and tone wheel from being impaired when a seal ring or tone wheel is fitted on the shoulder portion 27 or when the seal lip is slidably contacted with the outer peripheral surface of the shoulder portion 27. it can. Also in this example, when the plurality of rolling elements 5 arranged around the inner ring 3 are balls, the distance L _O3 from the center O of the rolling element 5 to the inner end face of the inner ring 3 is the rolling element 5. The diameter D ₅ is preferably 0.75 times or more (L _O3 ≧ 0.75D ₅ ). Since the configuration and operation of the other parts are the same as in the case of the first example described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Third example of embodiment]
Next, FIG. 6 shows a third example of the embodiment of the present invention. In the first example and the second example described above, the shaft member 2 is rotatably provided inside the non-rotating outer ring 4, whereas in this example, the outer ring 4 side rotates. I try to do it. That is, in the case of this example, this outer ring 4 becomes a hub that rotates together with the wheels. Since the rotation side and the stationary side are inward and outward in the diametrical direction, and the configuration and action other than that in which the inner and outer sides in the axial direction are partially reversed are the same as in the case of the first example described above. Equivalent parts are denoted by the same reference numerals, and redundant description is omitted.

[Fourth Example of Embodiment]
Next, FIG. 7 shows a fourth example of the embodiment of the present invention. The above-described first and second examples and the above-described third example are both wheel support hub units for rotatably supporting driven wheels that are not rotationally driven (the front wheels of FR vehicles and the rear wheels of FF vehicles). Whereas the invention is applied, in the case of this example, a wheel support hub for rotatably supporting drive wheels (the rear wheel of the FR vehicle, the front wheel of the FF vehicle, and all the wheels of the 4WD vehicle). The present invention is applied to a unit.

  Therefore, in the case of this example, the hub 32 corresponding to the shaft member is formed in a cylindrical shape, and the female spline portion 33 is formed on the inner peripheral surface of the hub 32. And the drive shaft 35 which attached to the constant velocity joint 34 and formed the male spline part in the outer peripheral surface is inserted in this female spline part 33. On the other hand, the inner ring 3 is fitted on the step 8 formed on the outer peripheral surface of the inner end of the hub 32, and a step 36 is formed near the inner end surface of the inner ring 3. The caulking portion 16 formed at the inner end portion of the hub 32 is caulked toward the step portion 36. In this state, the caulking portion 16 does not protrude inward from the inner end surface of the inner ring 3. Accordingly, the outer end surface of the main body portion 37 of the constant velocity joint 34 is in contact with the inner end surface of the inner ring 3. In this manner, with the outer end surface of the main body portion 37 in contact with the inner end surface of the inner ring 3, the nut 38 is screwed into a portion protruding from the outer end surface of the hub 32 at the distal end portion of the drive shaft 35. By further tightening, the inner ring 3 and the hub 32 are tightly held in the axial direction.

In the case of this example, when the plurality of rolling elements 5 arranged around the inner ring 3 are balls, preferably, the distance L ₃₆ from the center O of the rolling element 5 to the step surface of the step portion 36 is rolling the diameter D ₅ of the body 5 (see FIG. 3) 0.75 or more (L ₃₆ ≧ 0.75 D _5). Since the configuration and operation of the other parts are the same as in the case of the first example described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  In the case of this example, since a hollow cylindrical member is used as the hub 32, it may be difficult to make the cross-sectional area of the hub 32 larger than the cross-sectional area of the inner ring 3. However, in the structure of this example, since the inner ring 3 is strongly pressed against the stepped surface 12 of the hub 32 by the axial force based on the tightening of the nut 38 in the used state, the caulking portion is pressed from the inner ring 3 to the caulking portion 16. The force acting in the direction of loosening 16 is limited. Therefore, even if the relationship of the cross-sectional areas cannot be satisfied, the durability of the caulking portion 16 is not impaired.

FIG. 2 is a half sectional view showing a first example of an embodiment of the present invention. The partial expanded sectional view which shows the state which crimps the inner end part of a shaft member in order to fix an inner ring | wheel at the time of manufacture of the structure of a 1st example. Similarly, the partial expanded sectional view shown in the state before caulking the inner end part of a shaft member. AA sectional drawing of FIG. The half part sectional view showing the 2nd example of an embodiment of the invention. Sectional sectional drawing which shows the 3rd example. Sectional sectional drawing which shows the 4th example. The half part sectional view showing the 1st example of conventional structure. Sectional sectional drawing which shows the 2nd example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel support hub unit 2 Shaft member 3 Inner ring 4 Outer ring 5 Rolling element 6 Flange 7 First inner ring raceway 8 Step part 9 Second inner ring raceway 10 Male thread part 11 Nut 12 Step surface 13 First outer ring raceway 14 Second Outer ring raceway 15 mounting portion 16 caulking portion 17 locking concave portion 18 cylindrical portion 19 taper hole 20 pressing die 21 convex portion 22 concave portion 23 gap 24 curved surface portion 25 seal ring 26 lid body 27 shoulder portion 28 tone wheel 29 cover 30 sensor 31 step portion 32 Hub 33 Female spline part 34 Constant velocity joint 35 Drive shaft 36 Step part 37 Body part 38 Nut

Claims (2)

  A shaft member in which a first flange is formed on the outer peripheral surface of the one end, a first inner ring raceway formed directly or through an inner ring separate from the shaft member on the outer peripheral surface of the shaft member; A step portion formed on the other end portion of the shaft member and having a smaller outer diameter than a portion where the first inner ring raceway is formed, and a second inner ring raceway is formed on the outer peripheral surface and the step portion is formed. An inner ring fitted externally, a first outer ring raceway facing the first inner ring raceway and a second outer ring raceway facing the second inner ring raceway on the inner peripheral surface, and a second flange on the outer peripheral surface. Each of the outer rings, and a plurality of rolling elements provided between the first and second inner ring raceways and the first and second outer ring raceways, respectively, and the other end of the shaft member. The cylindrical part formed at the part protruding from the inner ring that is externally fitted to at least the step part is caulked outward in the diametrical direction. A wheel support hub unit in which an inner ring that is externally fitted to the stepped portion is pressed against an end surface of the stepped portion by a caulking portion that is formed by connecting the inner ring that is externally fitted to the stepped portion to the shaft member. In this case, the thickness of the cylindrical portion is reduced toward the leading edge in a state before the cylindrical portion is squeezed outward in the diametrical direction, and the cylindrical portion is squeezed outward in the diametrical direction. A hub unit for supporting a wheel, characterized in that the wall thickness of a caulking portion configured to suppress the end face of the inner ring that is externally fitted to the stepped portion decreases toward the tip.   The shaft member is a hollow cylindrical hub, and another step portion is provided on the inner circumferential surface of the inner ring at the end opposite to the step portion. The caulking portion suppresses the step surface of this other step portion. The wheel support hub unit according to claim 1, wherein a part of the constant velocity joint coupled to the hub is positioned so as to abut against an end face of the inner ring.

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