JP2005291501A - Rolling bearing unit for wheel support - Google Patents

Abstract

To fix an inner ring 3 to a shaft member 2 by caulking and expanding a cylindrical portion 21 of the shaft member 2, the inner ring 3 and caulking and spreading portions are hardly damaged.
An inclined surface 19 is formed on an inner peripheral surface of an end portion of an inner ring 3, and the cylindrical portion 21 is caulked and spread toward the inclined surface 19. The amount of deformation of the cylindrical portion 21 is small, it is difficult to damage the caulking and spreading portion, and the amount of deformation of the inner ring 3 can be reduced.
[Selection] Figure 1

Description

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

  The wheels of the automobile are supported on the suspension device by a rolling bearing unit for supporting the wheels. As wheel support rolling bearing units used in such a case, those described in, for example, Patent Documents 1 to 8 have been known. FIG. 8 shows an example of a wheel bearing rolling bearing unit that has been widely used in the past. The wheel support rolling bearing unit 1 includes a shaft member 2, an inner ring 3, an outer ring 4, and a plurality of rolling elements 5 and 5. Outer end of the outer peripheral surface of the shaft member 2 (outside means the side that is outward in the width direction when assembled to the automobile, and is the left side of each figure. On the contrary, the side that is closer to the center in the width direction Is the right side of each figure), and a second flange 6 for supporting the wheel is formed in a portion protruding from the outer ring 4 in 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.

  And the said inner ring | wheel 3 which formed the 2nd inner ring raceway 9 in the outer peripheral surface at this step part 8 is externally fitted. 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 locking recess 17 is caulked inward in the diametrical direction to prevent the nut 11 from loosening. Yes. A structure in which a pair of inner rings are externally fitted to the shaft member 2 and first and second inner ring raceways 7 and 9 are provided on the outer peripheral surfaces of the pair of inner rings has been conventionally known.

  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. The outer end openings of the installation spaces of the rolling elements 5 and 5 are closed by the seal ring 22, and the inner end openings are closed by the lid 29. In the illustrated example, balls are used as the rolling elements 5 and 5. However, in the case of a rolling bearing unit for supporting a wheel for an automobile having a heavy weight, tapered rollers may be used as these rolling elements. .

  In order to assemble the wheel-supporting rolling bearing unit 1 as described above to an automobile, the outer ring 4 is fixed to a suspension device by a first flange 15 formed on a part of the outer peripheral surface thereof, and the second flange 6 is Secure the wheels to the As a result, this wheel is rotatably supported with respect to the suspension device.

  Patent Document 7 describes a wheel support rolling bearing unit 1 having a structure as shown in FIG. In the case of the second example of this conventional structure, a portion of the cylindrical portion formed at the inner end of the shaft member 2 that protrudes inward from the inner end surface of the inner ring 3 is bent radially outward. The caulking portion 16 is formed. The inner ring 3 is sandwiched between the caulking portion 16 and the step surface 12 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 bearing rolling bearing 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 formed on the inner peripheral surface of the adjacent inner ring 3. A force directed outward in the diameter direction is applied. For this reason, the diameter of the inner ring 3 changes although it is slight. And when this amount of change becomes large, not only the possibility of occurrence of damage such as cracks in the inner ring 3 arises, but the work of maintaining the preload applied to the rolling elements 5, 5 at an appropriate value becomes troublesome. It may be difficult to ensure the durability of the wheel bearing rolling bearing unit 1 including the inner ring 3. In particular, in order to prevent the inner ring 3 from rotating with respect to the shaft member 2 in order to sufficiently secure the caulking strength of the caulking portion 16, the amount of deformation tends to increase, and the inner ring 3 It becomes difficult to ensure durability.

  In view of such circumstances, in Japanese Patent Application No. 8-36800, a spacer ring is provided between the end face of the inner ring and the caulking portion, and the force directed outward in the diameter direction due to the caulking portion forming operation is A structure received by a spacer ring is disclosed. According to the structure according to the present invention, the spacer ring receives most of the force directed outward in the diametrical direction that is generated along with the forming operation of the caulking portion. Therefore, almost no force directed outward in the diameter direction is transmitted to the inner ring, and damage to the inner ring can be prevented. However, even in the case of such a structure provided with a spacer ring, the amount of processing from the caulking portion itself and the cylindrical portion is large, and cracks are likely to occur due to deformation accompanying caulking work, and it is difficult to ensure durability. .

JP 63-106426 A Japanese Unexamined Patent Publication No. 63-184501 JP-A-62-214889 JP-A-3-31001 US Pat. No. 4,537,270 US Pat. No. 4,958,944 US Pat. No. 5,226,738 US Pat. No. 5,490,732

  In view of such circumstances, the wheel bearing rolling bearing unit of the present invention prevents the inner ring from changing its inner diameter based on the fixing operation of the inner ring, and makes it difficult to cause damage such as cracks in the caulking portion. The invention was invented for the purpose of reducing the cost by omitting the operation of forming the locking recesses and the caulking operation of the nuts for preventing the nuts from being loosened to fix the inner ring to the shaft member.

Each of the wheel support rolling bearing units of the present invention has a first flange on the outer peripheral surface and a double-row outer ring raceway on the inner peripheral surface, as in the conventional or the wheel support rolling bearing unit of the previous invention. Each including an outer ring, a shaft member provided with a second flange on the outer peripheral surface of the end, at least one inner ring having an inner ring raceway on the outer peripheral surface and externally fitted to the shaft member, and the inner ring And a plurality of rolling elements provided between the first and second inner ring raceways provided on the outer peripheral surface of the portion rotating together with the shaft member, and the double row outer ring raceways. Then, a part of the cylindrical portion formed at the end of the shaft member is caulked outward in the diametrical direction, and the inner ring is suppressed directly or via a spacer ring. By attaching, the inner ring is fixed to the shaft member.
In particular, in the rolling bearing unit for supporting a wheel according to the present invention, the outer periphery of the inner ring or a portion where the cylindrical portion is caulked and widened at the opening peripheral portion of the spacer ring that is fitted closer to the tip of the shaft member than the inner ring. The portion where the surface is pressed is a conical concave inclined surface whose inner diameter increases toward the opening end.

The operation of rotatably supporting the wheel with respect to the suspension device by the wheel supporting rolling bearing unit of the present invention configured as described above is the same as that of the conventional wheel supporting rolling bearing unit.
In particular, in the case of the rolling bearing unit for supporting a wheel according to the present invention, the inner diameter increases toward the opening end of the portion where the outer peripheral surface of the portion formed by caulking the cylindrical portion formed on the end portion of the shaft member is pressed. Since the conical concave surface is inclined, the amount of deformation of the caulking portion is small. For this reason, distortion generated in the caulking portion can be suppressed to be small, and damage such as cracking can be suppressed in the caulking portion. Further, in order to suppress the amount of deformation, the force applied to the members existing around the cylindrical portion on the outer side in the diameter direction can be reduced based on the formation of the caulking portion. As a result, even when the spacer ring is used, even when the spacer ring is not used, the force applied to the inner ring in the diametrically outward direction can be reduced to prevent damage to the inner ring.
Since the rolling bearing unit for supporting a wheel of the present invention is configured and operates as described above, the diameter of the inner ring is prevented from being changed, and the inner ring and the caulking and expanding portion for fixing the inner ring are provided with the inner ring. It is possible to reduce the possibility of damage based on the fixing work. In addition, the preload can be maintained at an appropriate value, and the cost can be reduced by reducing the number of parts, parts processing, and assembly man-hours.

More preferably, when implementing the present invention, the following constituents (1) to (6) are each independently, or a plurality of constituents selected from (1) to (6) are respectively: Implement in combination with the above essential requirements.
(1) The position of the tip of the circular recess formed at the end of the shaft member to constitute the cylindrical portion in the axial direction of the shaft member is the center of the rolling element that contacts the second inner ring raceway. It is located in the edge part side of the said shaft member rather than the position regarding the axial direction of the said shaft member.
(2) The distance in the axial direction of the shaft member between the center of the rolling element in contact with the second inner ring raceway and the end face of the inner ring or the shoulder end face of the inner ring is the outer diameter of the rolling element. It is 0.75 times or more.
(3) The outer diameter of the portion where the inclined surface is formed at the end of the inner ring is made smaller than the outer diameter of the shoulder of the inner ring.
(4) The outer diameter of the fitting portion of the inner ring or the portion protruding from the fitting portion of the inner ring and the spacer ring at the tip of the shaft member is made smaller than the outer diameter of the fitting portion, and the shaft A portion of the cylindrical portion formed at the end of the member with a reduced outer diameter is caulked outward in the diameter direction.
(5) A concave groove is formed in a part of the outer peripheral surface of the tip end portion of the shaft member and facing the small-diameter side end portion of the inclined surface over the entire circumference of the outer peripheral surface. A portion closer to the tip than the concave groove in the cylindrical portion formed at the end is caulked and spread outward in the diameter direction.
(6) The extended position of the line of action of the load applied to the inner ring from the rolling element is located closer to the center in the axial direction of the shaft member than the inclined surface, and the outer diameter of the shaft member does not change.

  FIGS. 1-2 has shown Example 1 of this invention incorporating the structural requirements of said (1) (2). 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. 8 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 inner diameter increases toward the inner end opening on the inner peripheral surface of the inner ring 3 of the inner ring 3 that is externally fitted to the step portion 8 at a portion near the inner end of the step portion 8 formed at the inner end portion of the shaft member 2. A conical concave surface 19 is formed. The inclination angle θ at which the inclined surface 19 is inclined with respect to the central axis of the shaft member 2 is about 20 to 60 degrees. Further, a cylindrical recess 21 is formed at the inner end of the shaft member 2 by forming a circular recess 20 on the inner end surface of the shaft member 2. In the case of the present embodiment, the cylindrical portion 21 is present at the inner end portion of the shaft member 2 and substantially at the inner portion of the shoulder portion 23 of the inner ring 3.

  The inner ring 3 having the inclined surface 19 as described above is fixed to the shaft member 2 by caulking and expanding the cylindrical portion 21 provided at the inner end portion of the shaft member 2, and the wheel bearing rolling bearing unit of the present invention. In this case, the amount of deformation of the caulking portion can be reduced as compared with the conventional structure shown in FIG. That is, in the case of the above-described conventional structure, in order to form the caulking portion 16, the cylindrical portion formed at the inner end portion of the shaft member 2 is bent 90 degrees outward in the diameter direction, whereas the wheel support of the present invention is When the cylindrical portion 21 is caulked and spread to form a rolling bearing unit, the cylindrical portion 21 may be deformed by the inclination angle θ (= 20 to 60 degrees). For this reason, distortion generated in the caulking portion can be suppressed to be small, and damage such as cracking can be suppressed in the caulking portion. Further, in order to suppress the deformation amount, the force applied to the inner ring 3 that is a member around the cylindrical portion 21 in the outer diameter direction of the inner ring 3 is reduced based on the formation of the caulking portion. Thus, damage to the inner ring 3 can be prevented.

  The operation of caulking the cylindrical portion 21 outward in the diametrical direction is performed by forging or swing pressing. Regardless of which processing method is employed, as shown in FIG. 2, a press die 25 is pushed into the inner diameter side of the cylindrical portion 21, and the cylindrical portion 21 is caulked outward in the diameter direction. In particular, the use of oscillating press working in the caulking work has the advantage that the load during molding can be reduced, the influence on the inside of the bearing can be eliminated, and the preload management after molding can be properly performed. Further, the distance L between the rear end edge of the cylindrical portion 21 (the rear end of the portion where the inner diameter of the cylindrical portion 21 does not change) and the end surface 24 of the inner ring 3 depends on the size of the wheel bearing rolling bearing unit. However, it is preferably about 5 to 15 mm in the case of a general rolling bearing unit for supporting a wheel for passenger cars.

  Further, in order to form the cylindrical portion 21, the tip position of the circular recess 20 formed at the end of the shaft member 2 is the rolling element constituting the inner row of the rolling elements 5 and 5 arranged in double rows. It is located inside the center of the moving body 5. That is, the position of the tip of the recess 20 in the axial direction of the shaft member 2 indicated by the point X in FIG. 1 is the second inner ring provided on the outer peripheral surface of the inner ring 3 which is the second inner ring raceway. The center of the rolling element 5 in contact with the track 9 is positioned closer to the inner end of the shaft member 2 than the position in the axial direction of the shaft member 2. Therefore, even when a radial load is applied between the shaft member 2 constituting the wheel supporting rolling bearing unit and the outer ring 4 and a radial load is applied from the rolling element 5 to the second inner ring raceway 9, the shaft member Since the part which receives this radial load in a part of 2 is a solid body, the durability of the shaft member 2 can be sufficiently secured.

  Further, the distance M in the axial direction of the shaft member 2 between the center of the rolling element 5 contacting the second inner ring raceway 9 and the end surface 24 of the inner ring 3 is defined as the outer diameter of each rolling element 5, 5. 0.75 times or more of D (M ≧ 0.75D). As described above, since the distance M between the center of the rolling element 5 and the end face 24 is secured, it is possible to prevent deterioration of the dimensional accuracy and shape accuracy of the shoulder portion 23 of the inner ring 3 and the second inner ring raceway 9 portion. Thus, the function of the wheel bearing rolling bearing unit can be secured. That is, since the dimensional accuracy and shape accuracy of each of these portions can be ensured satisfactorily, vibration and the like are prevented during operation of the wheel support rolling bearing unit, and the rolling surface of the rolling element 5 and the second inner ring are prevented. The rolling fatigue life of the track 9 can be secured. In the illustrated example, the first inner ring raceway 7 is formed directly on the outer peripheral surface of the intermediate portion of the shaft member 2, but the first inner ring raceway 7 is formed on the inner ring separate from the shaft member 2. The inner ring may be externally fitted and fixed to the shaft member 2.

  Next, FIG. 3 shows Embodiment 2 of the present invention that incorporates the structural requirements (1), (2), and (6). In the case of the present embodiment, the spacer ring 18 is fitted on the inner end portion of the shaft member 2 at a portion protruding inward from the end face 24 of the inner ring 3 fitted on the shaft member 2. On the inner peripheral surface of the inner half of the spacer ring 18, an inclined surface 19 having a conical concave shape is formed, the inner diameter of which increases toward the inner end opening. Then, the cylindrical portion 21 existing inside the spacer ring 18 is caulked and spread outward in the diametrical direction at the inner end portion of the shaft member 2, thereby pressing the spacer ring 18 toward the end surface 24 of the inner ring 3. The inner ring 3 is coupled and fixed to the shaft member 2. Further, the extension position of the line of action of the load applied to the inner ring 3 from the rolling elements 5 provided between the second inner ring raceway 9 and the second outer ring raceway 14 (corresponding to the chain line α representing the contact angle) is as described above. It exists in the part where an outer diameter does not change near the axial center of the step part 8 rather than the inclined surface 19.

  In the case of the present embodiment, by providing such a spacer ring 18, even when the caulking strength when caulking and expanding the cylindrical portion 21 is sufficiently increased, the inner ring 3 is reliably deformed elastically in the diameter direction. Can be prevented. That is, in the case of the present embodiment, the force directed outward in the diametrical direction, which is applied when the cylindrical portion 21 is caulked and spread, is received by the spacer ring 18 fitted on the shaft member 2. Therefore, the diameter of the inner ring 3 changes with the work of caulking the cylindrical portion 21 less than in the case of the first example described above (almost no change). Even if the dimensional accuracy and shape accuracy of the spacer ring 18 are deteriorated, the performance of the wheel bearing rolling bearing unit is not adversely affected. In the case of this embodiment, since the extension position of the line of action of the load is restricted, it is possible to prevent this load from acting on the part where the cylindrical part 21 is caulked and spread, Durability can be secured. The configuration and operation other than the point of providing the spacer ring 18 and the point of restricting the extended position of the action line are the same as in the case of the first embodiment.

  Next, FIG. 4 shows Embodiment 3 of the present invention in which the constituent features (1), (2), (3), and (6) are incorporated. In the case of the present embodiment, the outer diameter of the portion where the inclined surface 19 is formed at the inner end portion of the inner ring 3a fitted on the inner end portion of the shaft member 2 is made larger than the outer diameter of the shoulder portion 23 of the inner ring 3a. The inner ring cylindrical portion 26 is made smaller. In the case of this embodiment, the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is caulked outward in the diametrical direction toward the inclined surface 19, and the inner ring 3 is fixed to the shaft member 2. In this case, the inner ring cylindrical portion 26 receives most of the stress accompanying caulking and spreading. Accordingly, although the deformation amount of the thin inner ring cylindrical portion 26 is larger than that of the shoulder portion 23, the deformation amount of the shoulder portion 23 of the inner ring 3a and the second inner ring raceway 9 can be reduced. As a result, the rotational accuracy of the wheel supporting rolling bearing unit can be maintained in a sufficiently good state. In the case of this embodiment, the distance M in the axial direction of the shaft member 2 between the center of the rolling element 5 contacting the second inner ring raceway 9 and the end surface 24a of the shoulder 23 of the inner ring 3a. Is 0.75 times or more the outer diameter D of each of the rolling elements 5 and 5 (M ≧ 0.75D). Also in the present embodiment, the extension position of the load action line is regulated to ensure the durability of the caulking fixed portion. Other configurations and operations are the same as those of the first embodiment.

  Next, FIG. 5 shows Embodiment 4 of the present invention, which incorporates the structural requirements (1) and (2). In the first to third embodiments, the outer ring 4 is a stationary ring that does not rotate and the shaft member 2 is rotated. In the present embodiment, the shaft member 2 is a suspension device. The outer ring 4 is a rotating wheel that rotates together with the wheels without being supported and rotated. Except for the fact that the rotating side and the stationary side are reversed, the configuration and operation are the same as in the case of the first embodiment.

  Next, FIG. 6 shows Embodiment 5 of the present invention in which the constituent features (1), (2) and (4) are incorporated. In the case of the present embodiment, the outer diameter of the portion protruding from the fitting portion of the inner ring 3 at the inner end portion of the shaft member 2 is made smaller than the outer diameter of the fitting portion. That is, the outer peripheral surface of the base end portion of the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is slightly closer to the second inner ring raceway 9 than the inclined surface 19 formed at the inner end opening portion of the inner ring 3. A stepped portion 27 having a slight step H of about 0.02 to 1 mm is formed in the portion. And the part where the outer diameter became small among the said cylindrical parts 21 is caulked and spread outward in the diameter direction, and the said inclined surface 19 is suppressed. In this way, when the cylindrical portion 21 is caulked and spread outward in the diameter direction, the stepped portion 27 becomes a starting point of a portion that is bent along with caulking and spreading work. For this reason, it becomes difficult to apply an excessive force to the cylindrical portion 21 with the caulking and spreading work, and damage such as cracks is less likely to occur in the caulking and spreading portion. Other configurations and operations are the same as those of the first embodiment. When the structure of this embodiment is applied to the above-described embodiment 4, the inner and outer directions with respect to the axial direction are reversed.

  Next, FIG. 7 shows Embodiment 6 of the present invention in which the constituent features (1), (2) and (5) are incorporated. In the case of the present embodiment, a part of the outer peripheral surface of the inner end portion of the shaft member 2 is about 0.1 to 2 mm at a portion facing the small diameter side end portion of the inclined surface 19 formed at the inner end portion of the inner ring 3. A concave groove 28 having a depth K is formed over the entire circumference of the outer peripheral surface. A portion closer to the inner end than the concave groove 28 in the cylindrical portion 21 formed at the inner end portion of the shaft member 2 is caulked outward in the diametrical direction to suppress the inclined surface 19. . Thus, when the cylindrical portion 21 is caulked outward in the diametrical direction, the concave groove 28 becomes a starting point of a portion that is bent along with caulking and spreading work. For this reason, it becomes difficult to apply an excessive force to the cylindrical portion 21 with the caulking and spreading work, and damage such as cracks is less likely to occur in the caulking and spreading portion. Other configurations and operations are the same as those of the first embodiment. In addition, also when applying the structure of a present Example to Example 4 mentioned above, the inner / outer direction regarding an axial direction becomes reverse.

FIG. 2 is a half sectional view showing Example 1 of the present invention. The principal part expanded sectional view which shows the state which crimps and spreads the cylindrical part formed in the inner end part of a shaft member. Sectional drawing which shows the half part which shows Example 2 of this invention. Sectional sectional drawing which shows the Example 3. FIG. Sectional sectional drawing which shows the Example 4. FIG. The principal part expanded sectional view which shows the same Example 5. FIG. The principal part expanded sectional view which shows the Example 6. FIG. 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 Rolling bearing unit for wheel support 2 Shaft member 3, 3a Inner ring 4 Outer ring 5 Rolling element 6 Second 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 first flange 16 caulking portion 17 locking recess portion 18 spacer ring 19 inclined surface 20 recess portion 21 cylindrical portion 22 seal ring 23 shoulder portion 24, 24a end surface 25 press die 26 inner ring cylindrical portion 27 Stepped portion 28 Concave groove 29 Lid

Claims (1)

  A first flange on the outer peripheral surface, a double row outer ring raceway on the inner peripheral surface, an outer ring provided with each, a shaft member provided with a second flange on the outer peripheral surface of the end, and an inner ring raceway on the outer peripheral surface At least one inner ring externally fitted to the shaft member, and first and second inner ring raceways provided on an outer peripheral surface of a portion including the inner ring and rotating together with the shaft member, and the double row outer ring raceway In between, a plurality of rolling elements are provided, and a portion of the cylindrical portion formed at the end portion of the shaft member is squeezed outward from the inner ring in the diametrically outward direction. In a rolling bearing unit for supporting a wheel that fixes the inner ring to the shaft member by holding the inner ring directly or through a spacer ring by a portion, the tip of the shaft member rather than the inner ring or the inner ring The outer peripheral surface of the portion where the cylindrical portion is caulked and widened at the periphery of the opening of the spacer ring that is externally fitted is a conical concave inclined surface whose inner diameter increases toward the opening end. Rolling bearing unit for wheel support.

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