JP2009068617A - Hub unit for driving wheel support - Google Patents

Abstract

An object of the present invention is to easily carry out an outer fitting of an inner ring 3b to a small-diameter step portion 10 of a hub 2b from the inside in the axial direction in a correct posture, and a cylindrical portion 13a (caulking) provided at an axially inner end of the hub 2b. This realizes a structure in which the thickness in the radial direction of the portion 14a is not reduced.
An axially outer end portion of the inner peripheral surface of the inner ring 3b is used as a gap fitting fitting portion 22 that fits into the small diameter step portion 10 with a gap fitting, and an axially intermediate portion is also used as the small diameter step portion. An interference fit fitting portion 23 that fits with the interference fit 10 is provided. As a result, as shown in (A), in the initial stage of fitting the inner ring 3b to the small diameter step portion 10 from the inner side in the axial direction, the gap fitting fit to the axial inner end portion of the small diameter step portion 10 is performed. By fitting the joint portion 22 with a clearance fit, the small diameter step portion 10 and the inner ring 3b can be aligned with each other, thereby solving the above problem.
[Selection] Figure 1

Description

  The present invention supports the driving wheels of an automobile (front wheels of FF vehicles, rear wheels of FR vehicles and RR vehicles, all wheels of 4WD vehicles) rotatably with respect to a suspension system, and rotationally drives the driving wheels. The present invention relates to an improvement of a hub unit for driving wheel support used in the above.

  The driving wheel of the automobile is supported on the suspension device by a driving wheel supporting hub unit. FIG. 2 shows the structure described in Patent Document 1 among such driving wheel supporting hub units. This drive wheel support hub unit rotatably supports a hub 2 and an inner ring 3 on the inner diameter side of an outer ring 1 via a plurality of rolling elements 4 and 4. Out of these, the outer ring 1 is coupled and fixed to a knuckle (not shown) constituting the suspension device, and does not rotate during use. Further, first and second outer ring raceways 5 and 6 are provided on the inner peripheral surface of the outer ring 1, and the hub 2 and the inner ring 3 are rotatable on the inner diameter side of the outer ring 1 so as to be concentric with the outer ring 1. I support it.

  The hub 2 is the outer end in the axial direction of the outer peripheral surface ("outer" with respect to the axial direction refers to the outer side in the width direction of the vehicle when assembled to the automobile, and the left side of each figure. The right side of each figure is referred to as “inside” with respect to the axial direction.This is the same throughout the present specification and claims.) The mounting flange 7 for supporting and fixing the wheel is attached to the portion closer to the shaft. A first inner ring raceway 8 is formed at an intermediate portion in the direction, and a small-diameter step portion 10 having an outer diameter smaller than that of the portion where the first inner ring raceway 8 is formed at an axially inner end portion. Each hole 11 is provided. And the said inner ring | wheel 3 which formed the 2nd inner ring raceway 9 in the outer peripheral surface at the said small diameter step part 10 is externally fitted by interference fitting.

  Further, a large-diameter step portion 12 having a larger inner diameter than the axial intermediate portion or outer end portion is provided at the inner end portion in the axial direction of the inner peripheral surface of the inner ring 3. Then, a caulking portion 14 is formed by plastically deforming the tip end portion of the cylindrical portion 13 provided at the inner end portion in the axial direction of the hub 2 outwardly in the radial direction, and the caulking portion 14 forms the caulking portion 14. 12 step surfaces 15 are held down. Thereby, the inner ring 3 is coupled and fixed to the hub 2. Note that, as described above, the operation of plastically deforming the tip end portion of the cylindrical portion 13 outward in the radial direction is performed by a rocking press. In this state, the inner end surface 16 in the axial direction of the inner ring 3 protrudes inward in the axial direction from the caulking portion 14. A plurality of each of the rolling elements 4, 4 are provided between the first and second outer ring raceways 5, 6 and the first and second inner ring raceways 8, 9 so as to be freely rollable. Yes.

  When the hub unit for driving wheel support as described above is assembled to an automobile, a spline shaft 19 (drive shaft) fixed at the center of the axial outer end surface 18 of the outer ring 17 for a constant velocity joint is mounted as shown in the figure. The spline is engaged with the spline hole 11 of the hub 2. At the same time, the radially outer end portion of the axial outer end surface 18 of the constant velocity joint outer ring 17 is brought into contact with the axial inner end surface 16 of the inner ring 3. In this state, the hub 20 and the inner ring 3 are coupled to the spline shaft 19 by screwing the nut 20 into the tip of the spline shaft 19 and further tightening. In the case of such a conventional structure, the inner end surface in the axial direction of the caulking portion 14 is not brought into contact with the outer end surface 18 in the axial direction of the outer ring 17 for the constant velocity joint. For this reason, it is not necessary to finish the axial inner end face of the caulking portion 14 to a plane perpendicular to the central axis, and the manufacturing cost of the drive wheel supporting hub unit can be reduced.

  Next, FIG. 3 shows an example of the structure of the prior invention relating to a hub unit for driving wheel support, which has been developed in recent years. In the structure of the prior invention, the thickness of the caulking portion 14a formed at the inner end in the axial direction of the hub 2a is made smaller than in the case of the conventional structure described above. For this reason, the radial thickness of the cylindrical portion 13a provided at the inner end in the axial direction of the hub 2a, which is the element of the caulking portion 14a, is reduced. Specifically, the radial thickness of the cylindrical portion 13a is reduced by making the inner diameter size of the cylindrical portion 13a larger than the inner diameter size of the portion near the inner end in the axial direction of the hub 2a. Yes. In accordance with this, the size of the large-diameter step portion 12a provided at the inner end in the axial direction of the inner ring 3a is also reduced. In the case of such a structure of the prior invention, since the cylindrical portion 13a has a small thickness in the radial direction, the tip portion of the cylindrical portion 13a is plastically directed outward in the radial direction so as to form the caulking portion 14a. The force required to deform can be reduced. Since the structure and operation of the other parts are the same as in the case of the above-described conventional structure, the same parts are denoted by the same or similar reference numerals, and duplicate descriptions are omitted.

  By the way, in the case of a structure in which the inner ring 3 (3a) is externally fitted to the small-diameter step portion 10 formed at the axially inner end portion of the hub 2 (2a) as in the conventional structure or the structure of the previous invention described above. It is desirable that this outer fitting work, that is, the work of fitting the inner ring 3 (3a) to the small diameter step portion 10 from the inner side in the axial direction can be easily performed. In view of such circumstances, in the case of the conventional structure shown in FIG. 2 described above, conventionally, as shown in FIG. 4, the axially inner end of the outer peripheral surface of the small-diameter step portion 10a of the hub 2 is A guide surface portion 21 having an outer diameter slightly smaller than that of the outer peripheral end portion or the intermediate portion of the outer peripheral surface is provided. If such a guide surface portion 21 is provided, a gap is formed between the guide surface portion 21 and the outer end portion in the axial direction of the inner ring 3 in the initial stage of fitting the inner ring 3 to the small diameter step portion 10a from the inner side in the axial direction. The small diameter step portion 10a and the inner ring 3 can be aligned with each other by externally fitting. For this reason, the operation | work which externally fits this inner ring | wheel 3 to this small diameter step part 10a from the axial direction inner side with a correct attitude | position can be performed easily.

  Further, in the case of the structure of the prior invention shown in FIG. 3 as described above, as shown in FIG. 5, the axial outer end of the outer peripheral surface is arranged at the inner end of the outer peripheral surface of the small diameter step portion 10a of the hub 2a. If the guide surface portion 21 whose outer diameter dimension is slightly smaller than the intermediate portion or the intermediate portion is provided, the inner ring 3a is axially disposed on the small-diameter step portion 10a by the same action as the structure shown in FIG. It is possible to easily carry out external fitting with a correct posture from the inside. However, in the case of the structure of the previous invention, the cylindrical portion 13a having a small radial thickness is formed at the axially inner end portion of the hub 2a, so that the outer peripheral edge portion of the cylindrical portion 13a is as described above. If the guide surface portion 21 having a smaller outer diameter is provided, it may be difficult to secure a necessary amount of the radial thickness of the cylindrical portion 13a.

JP-A-9-164803

  In view of the circumstances as described above, the hub unit for driving wheel support according to the present invention can easily perform the work of externally fitting the inner ring from the inside in the axial direction to the small diameter step portion formed at the inner end of the hub in the axial direction. In addition, the invention has been invented to realize a structure in which the thickness in the radial direction of the cylindrical portion provided at the inner end portion in the axial direction of the hub does not decrease.

The hub unit for driving wheel support of the present invention includes a hub, an inner ring, an outer ring, and a plurality of rolling elements.
Of these, the hub has a flange for supporting the wheel on the outer peripheral portion of the outer peripheral surface in the axial direction, the first inner ring raceway in the middle in the axial direction, and the first inner ring in the inner end in the axial direction. Small-diameter steps each having a smaller outer diameter than the portion where the track is formed are formed.
The inner ring is externally fitted to the small-diameter step, and forms a second inner ring raceway on the outer peripheral surface.
Further, the outer ring forms a first outer ring track facing the first inner ring track and a second outer ring track facing the second inner ring track on the inner peripheral surface.
Each of the rolling elements is provided in plural between the first and second inner ring raceways and the first and second outer ring raceways.
Furthermore, the inner diameter of the inner ring is increased at the inner end of the inner ring in the axial direction at the inner end of the inner ring. An inclined surface portion inclined in the direction is provided. The stepped surface or the inclined surface portion existing between the axial intermediate portion and the large-diameter step portion is plastically deformed with the cylindrical portion provided at the axially inner end portion of the hub directed radially outward. The inner ring is coupled and fixed to the hub by being restrained by a caulking portion formed in this way. Further, the inner end surface in the axial direction of the inner ring protrudes inward in the axial direction from the inner end surface in the axial direction of the caulking portion.
In particular, in the hub unit for driving wheel support according to the present invention, the gap fitting fitting portion for fitting the axial outer end portion of the inner circumferential surface of the inner ring to the outer circumferential surface of the small diameter step portion by gap fitting. In the same manner, the intermediate portion in the axial direction is an interference fit fitting portion that fits into the outer peripheral surface of the small diameter step portion by interference fit.

  In the case of the hub unit for driving wheel support of the present invention configured as described above, at the initial stage of the work of externally fitting the inner ring to the small diameter step portion of the hub from the inner side in the axial direction, The small diameter step portion and the inner ring can be aligned with each other by fitting the gap fitting fitting portion provided at the outer end in the axial direction of the inner peripheral surface of the inner ring with the gap fitting. For this reason, the operation | work which externally fits this inner ring | wheel with this small diameter step part in the correct attitude | position from the axial direction inner side can be performed easily. Further, in the case of the present invention, a guide surface portion having a smaller outer diameter than the axially outer end portion or intermediate portion of the outer peripheral surface is formed at the inner end portion in the axial direction of the outer peripheral surface of the small diameter step portion. There is no need. And if such a guide surface part is not formed, the radial thickness of the cylindrical part (part which becomes the element of a caulking part) formed in the axial direction inner end part of the hub will not decrease. Therefore, it is possible to prevent the occurrence of inconvenience that it is difficult to ensure the thickness of the cylindrical portion in the radial direction.

  FIG. 1 shows an example of an embodiment of the present invention. The feature of this example is the structure of the inner peripheral surface of the inner ring 3b. Since the structure and operation of other parts are the same as the structure of the prior invention shown in FIG. 3 described above, overlapping illustrations and explanations are omitted or simplified, and the following description will focus on the characteristic parts of this example.

  In the case of this example, the inner diameter of the inner peripheral surface of the inner ring 3b is slightly larger than the inner diameter of the intermediate portion of the inner peripheral surface in the axial direction. The outer end portion in the direction is a gap fitting fitting portion 22 that is fitted to the small-diameter step portion 10 of the hub 2b with a gap fitting, and the axially intermediate portion of the inner peripheral surface is fitted to the small-diameter step portion 10 by an interference fit. The interference fit fitting portion 23 is used. In the case of this example, when the inner ring 3b is externally fitted to the small diameter step portion 10 from the inner side in the axial direction, first, as shown in FIG. The gap fitting fitting portion 22 provided at the axially outer end portion of the inner circumferential surface of the inner ring 3b is fitted with the gap fitting. Thereby, the said small diameter step part 10 and the said inner ring | wheel 3b are aligned.

  Next, as shown in (A) → (B), the inner ring 3 b is axially moved to the small diameter step portion 10 until the axially outer end surface of the inner ring 3 b comes into contact with the step surface 24 of the small diameter step portion 10. Push in. As a result, the interference fitting portion 23 provided at the intermediate portion in the axial direction of the inner peripheral surface of the inner ring 3b is fitted to the small diameter step portion 10 by interference fitting. In the case of this example, in this state {the state shown in Fig. 1B}, the tip of the cylindrical portion 13b provided at the axially inner end of the hub 2b is in the axial direction of the inner ring 3b. The dimensions of each part, including the inner diameter of the large-diameter stepped part 12a, are regulated so that it protrudes clearly (for example, 2 mm or more) inward in the axial direction from the inner end face 16. However, when the present invention is carried out, in the state of FIG. 1B, dimensional restriction is performed so that the tip of the cylindrical portion 13b does not protrude inward in the axial direction from the axial inner end surface 16. You can also. In any case, in the case of this example, as shown in (B) → (C), the caulking portion 14a is formed by plastically deforming the distal end portion of the cylindrical portion 13b outward in the radial direction. To do. Then, by this caulking portion 14a, the inner ring 3b is coupled and fixed to the hub 2b by suppressing the step surface 15a of the large-diameter step portion 12a provided at the inner end in the axial direction of the inner circumferential surface of the inner ring 3b. .

  As described above, in the case of the hub unit for driving wheel support of this example, the shaft of the small diameter step portion 10 is in the initial stage of the work of fitting the inner ring 3b from the inner side in the axial direction to the small diameter step portion 10 of the hub 2b. The center of the small-diameter step portion 10 and the inner ring 3b is formed by fitting a gap fitting fitting portion 22 provided at the outer end in the axial direction of the inner peripheral surface of the inner ring 3b at the inner end in the direction. Can be combined. For this reason, the operation | work which externally fits this inner ring | wheel 3b to this small diameter step part 10 in the correct attitude | position from the axial direction inner side can be performed easily. In the case of this example, a guide surface portion having a smaller outer diameter than the axially outer end portion or intermediate portion of the outer peripheral surface is formed at the inner end portion in the axial direction of the outer peripheral surface of the small diameter step portion 10. Not done. For this reason, the thickness in the radial direction of the cylindrical portion 13b (a portion serving as a base of the caulking portion 14a) formed at the inner end in the axial direction of the hub 2b does not decrease. Accordingly, it is possible to prevent the occurrence of inconvenience that it is difficult to secure the radial thickness of the cylindrical portion 13b and it is difficult to secure the coupling strength between the hub 2b and the inner ring 3b.

  Further, in the case of this example, as shown in (B), after the inner ring 3b is externally fitted to the small-diameter step portion 10 by the interference fit, the cylindrical portion is in a state before the caulking portion 14a is formed. The tip end of 13b protrudes inward in the axial direction from the axial inner end face 16 of the inner ring 3b. On the other hand, as shown in (C), in the state after the caulking portion 14a is formed, the caulking portion 14a does not protrude beyond the axial inner end surface 16 of the inner ring 3b. For this reason, on the basis of the presence of the tip of the cylindrical portion 13b protruding inward in the axial direction in this way, an unswaged product (a product in a state where the crimped portion 14a is not formed) and a crimped product This can be easily distinguished from the product (the product in which the caulking portion 14a is formed). That is, in the case of the drive wheel support bearing unit that is the object of the present example, since the caulking portion 14a is small, the tip portion of the cylindrical portion 13b before the caulking portion 14a is formed is the shaft of the inner ring 3b. If the inner end face 16 does not protrude inward in the axial direction, there is a case where it is difficult to distinguish the unswaged product from the crimped product. On the other hand, in the case of this example, as described above, such inconvenience can be solved. In the case of this example, the shaft of the inner ring 3b is formed by a horizontal obstacle (when the cylindrical portion 13b is positioned at the upper end) provided on the transfer line of the manufacturing plant, a photoelectric sensor, or the like. By checking whether or not the tip of the cylindrical portion 13b protrudes from the inner end surface in the direction, it is possible to automatically detect whether the product is the unswaged product or the crimped product.

BRIEF DESCRIPTION OF THE DRAWINGS It is principal part sectional drawing which shows an example of embodiment of this invention, (A) is the initial stage of the operation | work which externally fits an inner ring | wheel to the small diameter step part of a hub, (B) completes this external fitting operation | work. (C) shows the state after which the crimping part was formed in the axial direction inner end part of a hub after that, respectively. The half part sectional view which shows the state which connected the spline shaft of the constant velocity joint to one example of the conventional structure regarding the hub unit for driving wheel support. The half part sectional view which shows one example of the structure of the prior invention regarding the hub unit for driving wheel support. The principal part expanded sectional view which shows the structural example in which the small diameter guide surface part was formed in the axial direction inner end part of the small diameter step part of a hub in the said conventional structure in the state before forming a crimping part. The principal part expanded sectional view which shows the structural example which formed the small diameter guide surface part in the axial direction inner end part of the small diameter step part of a hub in the structure of the said invention in the state before forming a crimping part.

Explanation of symbols

1 outer ring 2, 2a, 2b hub 3, 3a, 3b inner ring 4 rolling element 5 first outer ring raceway 6 second outer ring raceway 7 mounting flange 8 first inner ring raceway 9 second inner ring raceway 10, 10a small diameter step 11 Spline hole 12, 12a Large diameter step portion 13, 13a, 13b Cylindrical portion 14, 14a Caulking portion 15, 15a Step surface 16 Axial inner end surface 17 Outer ring for constant velocity joint 18 Axial outer end surface 19 Spline shaft 20 Nut 21 Guide Surface part 22 Clearance fitting part 23 Interference fitting part 24 Step surface

Claims (1)

  A flange for supporting the wheel on the outer circumferential surface of the outer peripheral surface near the outer end in the axial direction, the first inner ring raceway in the middle in the axial direction, and the first inner ring raceway in the inner end in the axial direction. A small diameter step portion having a smaller outer diameter dimension, a hub formed on each of the small diameter step portions, an inner ring formed with a second inner ring raceway on the outer peripheral surface, and an inner ring formed on the outer peripheral surface by an interference fit. An outer ring forming a first outer ring raceway facing the first inner ring raceway and a second outer ring raceway facing the second inner ring raceway, the first and second inner ring raceways, and the first, first A plurality of rolling elements provided between each of the two outer ring raceways, and the inner diameter of the inner circumferential surface of the inner ring is larger than that of the inner circumferential surface of the inner circumferential surface. Provide a large diameter stepped part that has become larger or an inclined surface part that has a larger inner diameter as it goes inward in the axial direction. The step surface or the inclined surface portion existing between the axially intermediate portion and the large-diameter step portion is formed by plastically deforming the cylindrical portion provided at the axially inner end portion of the hub outward in the radial direction. The inner ring is coupled and fixed to the hub by being suppressed by a caulking portion, and the axial inner end surface of the inner ring protrudes inward in the axial direction from the axial inner end surface of the caulking portion. In the wheel support hub unit, the axially outer end portion of the inner peripheral surface of the inner ring is a gap-fitting fitting portion that is fitted to the outer peripheral surface of the small-diameter stepped portion by a clearance fit, and is also an axially intermediate portion. A hub unit for supporting a driving wheel, characterized in that an interference fitting portion that fits the outer peripheral surface of the small-diameter step portion with an interference fit.

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