JP2019100505A - Hub unit bearing and manufacturing method of hub unit bearing - Google Patents

Abstract

To provide a hub bearing unit which suppresses the deformation of an inner ring accompanied by caulking processing, and can secure sufficient rigidity even in a small-sized caulking part.SOLUTION: A hub bearing unit has a caulking part which is bent to the outside of a radial direction at an end part of a cylinder part of a hub main body in an axial direction, and an inner ring is compressed by the caulking part at its end face in the axial direction in a state of being externally fit to the cylinder part by interference fitment. The caulking part is constituted of a caulking main body part, and a caulking flange part adjoining an outside-diameter side of the caulking main body part, and an inside face of the caulking flange part in the axial direction is inclined substantially in parallel with an inner end face of an inner ring in the axial direction, or to a direction approximating the inner ring as progressing toward the outside in the radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hub unit bearing for rotatably supporting a wheel of a vehicle with respect to a suspension system, and a method of manufacturing the hub unit bearing.

  FIG. 5 shows an example of a conventional structure of a hub unit bearing that rotatably supports the wheels of a vehicle relative to a suspension. The hub unit bearing 1 includes an outer ring 2 that is a stationary wheel, a hub 3 that is a rotating wheel, and a plurality of tapered rollers 4 that are rolling elements.

The outer ring 2 has a pair of outer ring raceways 6a and 6b on the inner peripheral surface, and a mounting flange 7 on the outer peripheral surface. The hub 3 has a pair of inner ring raceways 8a and 8b and a hub flange 12 on the outer peripheral surface. The hub flange 12 is for supporting and fixing the wheel and the rotating wheel for braking.
The term "outside" with respect to the axial direction means the side on the outer side in the width direction of the vehicle in an assembled state with the vehicle, and is the left side in FIG. On the other hand, on the right side of FIG. 5, the side on the center side in the width direction of the vehicle is referred to as “in” in the axial direction.

  The hub 3 is configured by combining a hub body 10 and a pair of inner rings 11 and 11. The hub body 10 has a cylindrical portion 13, a step portion 14 and a crimped portion 15. The hub flange 12 is formed on the hub body 10. The cylindrical portion 13 is provided at an axially intermediate portion of the outer peripheral surface of the hub body 10, and has a cylindrical surface shape. The stepped portion 14 is formed between the axially inner surface of the hub flange 12 and the cylindrical portion 13 so as to face inward in the axial direction. The crimped portion 15 is formed at the axially inner end portion of the hub body 10 in a state of being bent radially outward.

The pair of inner rings 11 and 11 are the same members, and are externally fitted and fixed (press-fit) to the cylindrical portion 13 by close fitting in a state where the respective small diameter side end faces are butted.
The tapered rollers 4 are rollably disposed between the outer ring raceway surface 6a and the inner ring raceway surface 8a and between the outer ring raceway surface 6b and the inner ring raceway surface 8b while being held by the cage 5 respectively. ing.

  The axially outer end surface of the axially outer inner ring 11 press-fitted into the cylindrical portion 13 is in contact with (but against) the step portion 14. A portion of the axially inner end portion of the hub body 10 that protrudes axially inward relative to the axially inner end surface of the axially inner inner ring 11 is plastically deformed radially outward to form the crimped portion 15 doing.

When such a hub unit bearing 1 forms the caulking portion 15, a force (a caulking load) directed axially outward to the axial inner end (large diameter side end) of the axially inner inner ring 11. Axial component) of the Due to this caulking load, the inner ring raceway surface 8b formed on the outer peripheral surface of the inner ring 11 disposed inward in the axial direction may be deformed so as to expand radially outward.
Patent Document 1 describes a technique for forming crowning on each inner ring raceway and forming the crowning amount smaller than the crowning amount of the inner ring raceway surface on the axially outer side of the inner ring raceway surface in the axial direction. . However, in the case of the technique described in Patent Document 1, the crowning applied to the inner ring raceway surface is different, so that the pair of inner rings can not be made the same part, which may increase the manufacturing cost. .

Further, the inner ring 11 constituting the tapered roller bearing supports the tapered roller 4 at two points, the inner ring raceway surface 8 b and the large collar portion 32. For this reason, high rigidity is required for the nodular portions of the inner ring raceway surface 8b and the large heel portion 32. From the viewpoint of securing the thickness, the main chamfer 34 of the inner ring 11 is enlarged (the radius of curvature of the main chamfer 34 is It is not preferable to make it bigger.
However, when the caulking portion 15 is formed by a processing method of forming a caulking portion with a caulking die that has been rocked as described in Patent Document 2 with respect to the main chamfer in which the radius of curvature is reduced, During the caulking process, the internal stress of the axially inner end portion (the caulked portion) of the hub body 10 may be insufficient. In addition, since the caulking portion is caulked and expanded with a small radius of curvature, it is necessary to reduce the size (volume) of the caulking portion, and it has been difficult to provide the caulking portion 15 with sufficient strength.

Japanese Patent Application Publication No. 2003-97567 JP, 2009-19706, A

  In view of the above-described circumstances, the present invention provides a hub unit bearing and a method of manufacturing a hub unit bearing that can suppress the deformation of the inner ring accompanying caulking processing and secure sufficient strength even with a small-sized caulking portion. Task is to

  The hub unit bearing according to the present invention comprises an outer ring, a hub, and a plurality of tapered rollers, the outer ring having a double row outer ring raceway surface on the inner circumferential surface, and the hub on the outer circumferential surface It has a double-row inner ring raceway surface and is composed of a hub body and an inner ring, and the hub body has a cylindrical portion on the outer peripheral surface, and radially outward at the axially inner end of the cylindrical portion The inner ring has the inner ring raceway surface on the outer peripheral surface, and in the state of being externally fitted and fixed to the cylindrical portion, the inner end face in the axial direction is held down by the crimped portion. The tapered roller is disposed so as to be able to roll between the outer ring raceway surface and the inner ring raceway surface.

In particular, in the hub unit bearing according to the present invention, the caulking portion is constituted by a caulking main body portion and a caulking collar portion adjacent to the outer diameter side of the caulking main body portion. The axially inner side surface is inclined in a direction approaching the inner ring as it extends substantially parallel to the axially inner end surface of the inner ring or radially outward.
Furthermore, in the hub unit bearing according to the present invention, the boundary between the caulking flange and the caulking main body is located more radially inward than the inner diameter end of the small collar of the inner ring.
Further, in the case of manufacturing the hub unit bearing of the present invention, the caulking portion is formed by a swing pressing process in which a caulking die is pressed against the axial inner end portion of the hub body, and the caulking die is It has a concave surface portion for forming the caulking body portion, and an inclined surface portion provided adjacent to the outer diameter side of the concave surface portion to form the caulking flange portion, and the inclined surface portion The tilt angle is the same as or slightly smaller than the swing angle of the clamping die.

  According to the hub unit bearing according to the present invention, it is possible to suppress the deformation of the inner ring caused by the caulking process and to secure sufficient strength even with a caulking portion of a small size.

FIG. 3 is a cross-sectional view of a hub unit bearing showing an embodiment of the present invention. The fragmentary sectional view which takes out and shows the inner ring peripheral part of FIG. Explanatory drawing which shows the manufacturing method of the crimp part of FIG. Sectional drawing of a hub unit bearing which shows the modification of embodiment. Sectional drawing of a hub unit bearing which shows one example of conventional structure.

  1 and 2 show a hub unit bearing according to an embodiment of the present invention. The hub unit bearing 1a according to the present embodiment is used to rotatably support the driven wheel with respect to the suspension device (knuckle), and includes an outer ring 2 which is a stationary ring, a hub 3a which is a rotating ring, A plurality of tapered rollers 4 which are moving bodies are provided.

  The outer ring 2 has double rows of outer ring raceways 6a and 6b provided on the inner peripheral surface, and a mounting flange 7 provided on the outer peripheral surface. The double-row outer ring raceway surfaces 6a and 6b have a conical concave shape inclined in a direction in which the diameter (inner diameter) becomes larger as it goes away from each other in the axial direction. The mounting flange 7 is for coupling and fixing the hub unit bearing 1a to the suspension system.

  The hub 3a has double-row inner ring raceways 8a and 8b provided on the outer peripheral surface, and a hub flange 12 provided on the axially outer portion. The double-row inner ring raceway surfaces 8a and 8b have a conical convex shape which is inclined in a direction in which the diameter (outer diameter) becomes larger as it goes away from each other in the axial direction. The hub flange 12 is for supporting and fixing the wheel and the braking rotating body, and is provided on the axially outer portion of the outer peripheral surface of the hub 3a.

The hub 3a is configured by combining a hub body 10a and a pair of inner rings 11a and 11b.
The hub body 10 a includes the hub flange 12, the cylindrical portion 13, the step portion 14, and the crimped portion 15 a described above. The cylindrical portion 13 is provided at an axially intermediate portion of the outer peripheral surface of the hub body 10a, and except for both axial end portions (connections with the step portion 14 and the caulking portion 15a), the diameter changes in the axial direction. Not a single cylindrical surface. The stepped portion 14 is provided between the axially inner surface of the hub flange 12 and the cylindrical portion 13 so as to face inward in the axial direction. The outer diameter of the step portion 14 is equal to or less than the outer diameter of the axially outer end surface of the axially outer inner ring 11a described later, thereby avoiding interference with the seal ring 21 described later. The crimped portion 15a is provided at the axially inner end portion of the hub body 10a in a state of being bent radially outward.

The pair of inner rings 11a and 11b are identical members, and are externally fitted and fixed (press-fit) to the cylindrical portion 13 by close fitting in a state in which the small diameter side end faces are in contact with each other. A single row inner ring raceway surface 8a is provided on the outer circumferential surface of the inner ring 11a disposed axially outside, and a single row inner ring raceway surface 8b is disposed on the outer circumferential surface of the inner ring 11b disposed axially inside It is done.
As shown in FIG. 2, a large rib 32 is provided at each end of the inner ring raceway surface 8b (8a) at the large diameter end and a small rib 33 is provided at the small diameter end. There is. In addition, at the inner diameter side end portions of the large collar portion 32 and the small collar portion 33, relief portions recessed inward in the radial direction are respectively formed.

  The tapered rollers 4, which are rolling elements, can be rolled between the outer ring raceway surface 6a and the inner ring raceway surface 8a and between the outer ring raceway surface 6b and the inner ring raceway surface 8b while being held by the cage 5 respectively. Is located in

  A seal ring 21 is provided between the axially outer end portion inner circumferential surface of the outer ring 2 and the axially outer end portion (large diameter side end portion) outer circumferential surface of the inner ring 11a. Further, a cylindrical cover 20 with a bottom is attached (internally fixed) to the axially inner end portion of the outer ring 2. Thereby, the axial direction both end opening part of internal space 22 which installed tapered roller 4 is closed, the grease enclosed in internal space 22 leaks outside, or the foreign substance which exists in external space penetrates into internal space 22 It is preventing doing. Further, an encoder 23 is externally fitted and fixed to the axially inner end (large diameter side end) of the axially inner inner ring 11b. The detection speed of the hub 3a (wheel) can be detected by causing a detection unit of a sensor (not shown) to face the encoder 23 via the cover 20.

  When assembling the hub unit bearing 1a of the present embodiment, the tapered rollers 4 and the pair of inner rings 11a and 11b into which the cage 5 is incorporated are disposed on the inner side in the radial direction of the outer ring 2, and the seal ring 21 is mounted. Assemble the assembled outer ring assembly (intermediate assembly). The outer ring assembly is press-fit into the cylindrical portion 13 of the hub body 10a in a state where the small diameter side end faces of the pair of inner rings 11a and 11b are butted, and the axially outer end face of the inner ring 11a is brought into contact with the step portion 14 (Strike). Then, a portion of the axially inner end portion of the hub body 10a that protrudes inward in the axial direction with respect to the axially inner end surface of the inner ring 11b is plastically deformed radially outward to form a crimped portion 15a. The caulking portion 15a presses the pair of inner rings 11a and 11b axially outward toward the step portion 14 to apply a preload to the tapered rollers 4 arranged in multiple rows by the contact angle of the back combination type. ing.

  The caulking portion 15a is, as shown in FIG. 2, a caulking main body portion 30 that abuts on an inner diameter side of an axial inner end surface (upper side surface in FIG. 2) of the inner ring 11b; A caulking flange portion 31 continuously extends from the portion to the outer diameter side and abuts on a radially intermediate portion of the axially inner end surface of the inner ring 11b. The caulking main body portion 30 is formed such that the inner surface in the axial direction is arc-shaped in cross section, the axial thickness is increased, and the inner ring 11b is pressed outward in the axial direction by a large pressing force. The caulking flange portion 31 is formed in an annular shape as a whole, and is formed in a plane in which the axially inner side surface is substantially parallel to the axially inner end surface of the inner ring 11 b. The axial thickness T31 of the caulking flange 31 is substantially constant in the radial direction, and the maximum thickness T30 of the caulking main body 30 (the axial inner end surface of the inner ring 11b and the axial inner direction of the caulking main body 30 30-40% of the distance between the end portion).

The radial dimension D30 of the boundary between the caulking main body 30 and the caulking flange 31 is smaller than the inner diameter D33 of the small ridge 33 (including the above-mentioned relief) of the inner ring 11b (D30 <D33). That is, the boundary is located more radially inward than the small rib portion 33. With this configuration, the large pressing force of the caulking main body portion 30 suppresses the influence on the shape of the inner ring raceway surface 8 b.
Further, the outer diameter D31 of the contact surface where the caulking flange portion 31 contacts the inner ring 11b is smaller than the inner diameter D32 of the large collar portion 32 (including the relief portion) of the inner ring 11b (D31 <D32). That is, the outer diameter of the contact surface is located on the inner diameter side of the large flange portion 32. This configuration prevents the crimped portion 15a from displacing (tilting) the large rib portion 32 outward in the axial direction.

  The processing step (oscillating press processing) for forming the caulking portion 15a using the caulking die 35 will be described with reference to FIG. Before the caulking process, the axially inner end of the hub body 10a has a hollow cylindrical shape (not shown). With the outer ring 2 rotated, the axially inner end of the cylindrical portion is axially inward. And press the concave surface portion 36 of the caulking die 35. Then, a force is applied in the axially outward direction (downward direction in FIG. 3) to the caulking die 35 rocked and moved in a state of being inclined by the rocking angle α with respect to the central axis of the hub body 10a. The entire axially inner end portion of the hub body 10a is pressed axially outward as well as to the diameter expansion side, and the axial dimension is reduced and the radial dimension is expanded along the main chamfer 34a of the inner ring 11b. Plastic deformation gradually.

  A predetermined tightening force acts on the inner ring 11b until the caulking portion 15a is formed by plastic deformation, and a compressive stress is applied to the axially inner end portion (the caulked portion) of the hub body 10a. Occur. The main chamfer 34a of the inner ring 11b has a relatively small radius of curvature (the hollow cylindrical caulked portion of the hub body 10a before caulking) in order to secure the strength between the inner ring raceway surface 8b and the large rib portion 32. Is 70 to 75% of the thickness of the wall thickness, but the size of the caulking main body 30 constituting the caulking portion 15a is reduced, and the caulked portion is formed during caulking Enough compressive stress to enable stable caulking processing.

  The caulking die 35 is provided with an inclined surface portion 37 adjacent to the outer diameter side of the concave surface portion 36 for forming the caulking body portion 30. The inclined surface portion 37 is an annular flat surface, and has an inclination angle β (an angle obtained by subtracting the half-angle opening angle from 90 degrees) with respect to the central axis of the caulking die 35 substantially the same as the swing angle α. With this configuration, the axially inner surface of the caulking flange 31 is substantially parallel to the axial inner end surface of the inner ring 11 b (the axial thickness of the caulking flange 31 is substantially constant).

According to the hub unit bearing 1a of the present embodiment as described above, the amount of deformation of the pair of inner rings 11a and 11b associated with the assembly (cladding) of the hub unit bearing 1a is suppressed to a small amount, and the small size is crimped. Sufficient strength can be secured in the department.
That is, in the case of the present embodiment, the meat protruding to the outer diameter side from the caulking main body 30 molded by the concave surface portion 36 of the caulking die 35 is molded into a thin flange shape by the inclined surface 37 and caulked The portion 31 is formed. Further, since the size of the crimped portion 15a is reduced, the axially inner end surface of the inner ring 11b and the crimped die 35 are axially close to each other. The meat protruding from the concave surface portion 36 to the outer diameter side becomes a thin flange-like caulking flange portion 31, so the flowability is poor and the meat tends to stay in the concave surface portion 36. For this reason, since compressive stress is easily applied to the entire portion to be crimped, large caulking deformation is given while enabling stable caulking and most of the meat of the portion to be crimped before caulking is added. It can be deformed to the fastening main body 30. Therefore, the shape (the maximum thickness T30 in the axial direction) of the caulking body portion 30 can be processed into a constant shape in the circumferential direction, and the strength of the caulking portion 15a can be made constant without variation in the circumferential direction.

  If there is a variation in circumferential thickness at the axially inner end (clamped portion) of the hub body 10a before caulking, the caulking body 30 is formed into a stable shape, The outer diameter of the caulking flange 31 protruding from the concave surface portion 36 of the caulking die 35 changes. Accordingly, the shape of the caulking body 30 of the caulking portion 15a becomes constant in the circumferential direction, and the volume of the caulking body 30 is prevented from being dispersed in the circumferential direction, and the required caulking strength is stably obtained. I can do things. Although the outer diameter of the caulking flange 31 varies, the shape of the caulking main body 30 is stable, so there is almost no influence on the strength of the caulking portion 15a.

  Further, since the boundary between the caulking main body 30 and the caulking flange 31 is located on the inner diameter side of the inner diameter D33 of the small collar 33 of the inner ring 11b, the axial force applied by the caulking main body 30 ( The caulking load suppresses deformation of the inner ring raceway surface 8b (change of the angle of the inner ring raceway surface 8b) or change of the angle formed by the large rib portion 32 and the inner ring raceway surface 8b. Therefore, since the contact position between the head of the tapered roller 4 and the large flange portion 32 is more stable, a low torque design can be achieved by further bringing this contact position closer to the relief groove.

  Further, the outer diameter side of the caulking portion 15a is formed as a thin flange-like caulking collar portion 31, and the outer diameter D31 of the contact surface where the caulking collar portion 31 contacts the axial inner end surface of the inner ring 11b is , And the inner diameter side of the inner diameter D32 of the large collar portion 32. For this reason, axial force due to caulking is less likely to be transmitted to the girth 32, and deformation of the girth 32 (angle change of the girth 32) is suppressed. The contact position with the girdle portion 32 is further stabilized.

  As described above, according to the hub unit bearing 1a of this embodiment, even when the pair of inner rings 11a and 11b are pressed axially outward toward the step portion 14 by the caulking portion 15a, the pair of inner rings is The amount of deformation of 11a and 11b can be kept small. Therefore, the same thing can be used as a pair of inner rings 11a and 11b (parts can be made common), parts management can be made easy, and the manufacturing cost of hub unit bearing 1a can be reduced.

FIG. 4 shows a modification of this embodiment. The hub unit bearing 1b of this modification is a so-called third generation hub unit bearing, and the inner ring raceway surface 8a on the outer side in the axial direction is formed on the outer peripheral surface of the hub main body 10b, thereby eliminating the inner ring 11a. Therefore, the inner race 11b is held between the stepped portion 14a and the caulking portion 15b in a state of being externally fitted to the cylindrical portion 13a formed on the inner side in the axial direction of the hub main body 10b.
The hub unit bearing 1b is a hub unit bearing for a drive wheel, and a spline hole 25 for coupling and fixing the drive shaft is provided so as to penetrate the central portion of the hub body 10b in the axial direction. The axially inner end of the inner space 22 is sealed by a combination seal ring 24 instead of the cover.

  In the case of this modification, the caulking portion 15b inclines in the direction approaching the axial inner end surface of the inner ring 11b as the axially inner side surface of the caulking flange portion 31a goes radially outward (radially outward The inclined surface is inclined in the direction in which the thickness in the axial direction decreases in the direction of the arrow, and the effect of holding the meat of the caulking body 30 is enhanced. Such a crimped portion 15b is formed by making the inclination angle β of the inclined surface portion 37 of the crimping die 35 (see FIG. 3) slightly smaller than the swing angle α.

  The present invention is preferably applied to a hub unit bearing using a tapered roller as a rolling element as in the embodiment described above. However, the present invention can also be applied to a hub unit bearing using a ball as a rolling element. In this case, it is possible to suppress the variation in the radius of curvature with respect to the cross-sectional shape of the inner ring track of the inner ring.

1, 1a, 1b Hub unit bearing 2 Outer ring 3, 3a, 3b Hub 4 tapered roller (rolling element)
Reference Signs List 5 cage 6a, 6b outer ring raceway surface 7 mounting flange 8a, 8b inner ring raceway surface 10, 10a, 10b hub body 11, 11a, 11b inner ring 12 hub flange 13, 13a cylindrical portion 14, 14a step portion 15, 15a, 15b Tightening part 20 cover 21 seal ring 22 internal space 23 encoder 24 combination seal ring 25 spline hole 30 caulking main body 31, 31a caulking flange 32 large collar 33 small collar 34, 34a main chamfer 35 caulking type 36 concave Curved surface 37 sloped surface

Claims (3)

It has an outer ring, a hub, and several tapered rollers,
The outer ring has a double row outer ring raceway surface on the inner circumferential surface,
The hub has a plurality of inner ring raceways on the outer peripheral surface, and is composed of a hub body and an inner ring,
The hub body has a cylindrical portion on an outer peripheral surface, and has a crimped portion bent radially outward at an axially inner end portion of the cylindrical portion.
The inner ring has the inner ring raceway surface on the outer peripheral surface, and in a state of being externally fitted and fixed to the cylindrical portion, the axially inner end surface is pressed by the caulking portion,
The tapered roller is a hub unit bearing, which is rotatably disposed between the outer ring raceway surface and the inner ring raceway surface,
The caulking portion is constituted by a caulking body portion and a caulking flange portion adjacent to the outer diameter side of the caulking body portion,
A hub unit bearing characterized in that an axially inner surface of the caulking flange portion is substantially parallel to the axially inner end surface of the inner ring, or is inclined in a direction approaching the inner ring as it goes radially outward. .   The hub unit bearing according to claim 1, wherein a boundary between the caulking flange portion and the caulking main body portion is positioned on the inner diameter side of the inner diameter end of the small collar portion of the inner ring. A method of manufacturing a hub unit bearing according to claim 1 or 2,
The caulking portion is formed by swing press processing for pressing a caulking die against the axial inner end of the hub body, and the caulking die includes a concave surface portion for forming the caulking body portion, and the concave portion. And an inclined surface portion provided adjacent to the outer diameter side of the curved surface portion to form the caulking flange portion,
A method of manufacturing a hub unit bearing, characterized in that the inclination angle of the inclined surface portion is the same as or slightly smaller than the rocking angle of the caulking die.

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