JPH115404A - Wheel supporting hub unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of a caulking part without complicating the shape of a uniform motion joint by providing a flat surface, which can freely contact with a stage difference surface, in an inner end surface of a caulking part of an abutment part of a stage part, which is formed in an inner end part of a driving shaft, and a stage difference part. SOLUTION: An inner end surface of a caulking part 9a formed at an inner end of a hub 13a is formed with at least one part (a part close to the periphery) of a circular flat surface 21, which is vertically formed in relation to the center shaft of the hub 13, by coining or cutting so as to be positioned outside in the radial direction than the inner peripheral surface of an inner wheel 3b fitted on a stage part 7 of the hub 13a. In the condition that the hub 13a and a driving shaft 16 are connected to each other, an inner end surface of the caulking part 9a and a step difference surface 19 of a stepped part 18, which is formed in a base end of the driving shaft 16, are brought into surface-contact with each other over the full circumference, and the surface pressure to be applied to the inner end surface of the caulking part 9a with the nut fastening force can be reduced. With this structure, in the case where a large axial load is applied to the caulking part 9a, plastic deformation of the caulking part 9a is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A wheel supporting hub unit according to the present invention rotates a driving wheel of an automobile (a front wheel of an FF vehicle, a rear wheel of an FR vehicle and an RR vehicle, and all wheels of a 4WD vehicle) with respect to a suspension system. Use to support freely.

[0002]

2. Description of the Related Art Wheels of a motor vehicle are supported on a suspension system by wheel supporting hub units. FIG. 4 shows US Pat.
No. 90732. 1 shows an example of a wheel supporting hub unit for supporting driven wheels of an automobile (rear wheels of an FF vehicle, front wheels of an FR vehicle and an RR vehicle) with respect to a suspension device. The hub unit 1 for supporting the wheel includes a hub 2
, A pair of inner races 3a, 3b, an outer race 4, and a plurality of rolling elements 5, 5. Of these, the outer end portion of the outer peripheral surface of the shaft member 2 (the “outside” refers to the side that is shifted outward in the width direction when assembled to an automobile, and is the left side in each of the drawings including FIG. 4. The side closer to the inner side is called the inner side, and is on the right side of each drawing.), A flange 6 for supporting the wheel is formed. A step 7 is formed at the base end of the flange 6 near the center of the shaft member 2.

The pair of inner races 3a and 3b are fitted over the shaft member 2 from the middle part to the inner end, and the outer end surface of the outer inner race 3a is fitted to the step surface of the step part 7. The outer end face of the inner inner ring 3b is abutted against the inner end face of the outer inner ring 3a. A cylindrical portion 8 is provided at the inner end of the shaft member 2.
And the inner half of the inner ring 3b is formed at the first half of the cylindrical portion 8.
The caulking portion 9 is formed by caulking and expanding a portion protruding inward from the inner end face in the radial direction outward. The pair of inner rings 3a and 3b are sandwiched between the caulking portion 9 and the step surface of the step portion 7.

A pair of (first and second) outer raceways 10 and 10 provided on the inner peripheral surface of the outer race 4 and each of the inner races 3 are provided.
(1st, 2nd) inner ring track 1 provided on the outer peripheral surface of a, 3b
A plurality of the rolling elements 5, 5 are provided between the rolling elements 1 and 11, respectively. Although balls are used as the rolling elements 5 and 5 in the illustrated example, tapered rollers may be used as these rolling elements in the case of a wheel supporting hub unit for a heavy automobile. In some cases, the (first) inner raceway near the flange 6 is formed directly on the outer peripheral surface of the shaft member 2 and the outer inner race 3a is omitted. In this case, the step 7 is formed at a position corresponding to the inside of the outer inner ring 3a shown in FIG. In order to assemble the wheel supporting hub unit 1 as described above to an automobile, an outward flange-shaped mounting portion 12 formed on the outer peripheral surface of the outer ring 4 is used.
The outer ring 4 is fixed to a suspension device, and the wheel is fixed to the flange 6. As a result, the wheels can be rotatably supported by the suspension device.

On the other hand, FIG. 5 shows a structure in which a caulking portion for holding the inner ring against the hub as described above is formed, and a wheel support for supporting the driving wheels of the automobile to the suspension system. This is applied to a hub unit for use. This figure 5
In the case of the wheel supporting hub unit 1a for driving wheels shown in FIG.
3, a female spline portion 14 is formed on the inner peripheral surface. A drive member is formed in the female spline portion 14 together with a constant velocity joint 15 described later, and a drive shaft 16 having a male spline portion formed on the outer peripheral surface is inserted. Then, the inner end surface of the nut 17 screwed to the distal end of the drive shaft 16 is provided on the outer end surface of the hub 13, and the step surface 19 of the step 18 formed on the base end of the drive shaft 16 is provided on the hub 13. The hub 13 and the drive shaft 16 are connected by tightening the nuts 17 in a state of being in contact with the inner end surfaces of the caulking portions 9 formed at the inner end portions.

The hub unit 1a for supporting wheels for driving wheels shown in FIG. 5 is different from the hub unit 1 for supporting wheels for driven wheels shown in FIG. Is omitted, and a pair of inner raceways 11, 1
The inner raceway 11 of the outer ring 1 is formed directly on the outer peripheral surface of the hub 13. Therefore, the step 7 is formed at the inner end of the hub 13. In order to connect the hub 13 and the drive shaft 16, when the drive shaft 16 is inserted inside the hub 13, the inner peripheral surface of the inner end of the hub 13 and the outer peripheral surface of the inner end of the drive shaft are In order not to interfere with each other, a gap is formed over the entire circumference between these two peripheral surfaces.
The wheel supporting hub unit 1a for driving wheels as described above is
Similar to the wheel supporting hub unit 1 for the driven wheel described above,
It is fixed to a suspension device by a mounting portion 12 provided on the outer race 4.
When the vehicle is running, the drive shaft 16 is rotationally driven via the constant velocity joint 15, and the wheel fixed to the flange 6 of the hub 13 is rotated by the rotational driving force.

[0007]

However, in the case of the wheel supporting hub unit 1a for driving wheels shown in FIG. 5, the hub 13 and the driving shaft 16 are screwed together with the nut 17 as described above.
When the connection is performed based on the tightening, the inner end surface of the caulked portion 9 and the step surface 19 of the step portion 18 formed at the base end portion of the drive shaft 16 are in line contact over the entire circumference. That is, as shown in detail in FIG.
The shape of the inner end surface of the caulked portion 9 is formed by bending the inner end of the cylindrical portion 8 formed at the inner end of the hub 13 radially outward to form the caulked portion 9. It has become. Therefore, when the nut 17 is screwed and tightened as described above, the top 20 of the convex curved surface formed on the inner end face of the caulking portion 9 and the step surface 19 abut on the entire circumference, and these caulking are performed. The inner end surface of the portion 9 and the step surface 19 are in line contact.

As described above, the inner end surface of the caulked portion 9 and the step surface 19
When a line contact is made, the surface pressure applied to the inner end surface of the caulked portion 9 based on the tightening force of the nut 17 becomes extremely large. Since the caulked portion 9 is not subjected to hardening treatment such as quenching due to the necessity of forming the caulked portion 9,
When a large surface pressure is applied as described above, the caulked portion 9 is easily plastically deformed. When the caulking portion 9 is plastically deformed in this manner, the nut 17 screwed and tightened to the tip of the drive shaft 16 may be loosened. In order to prevent plastic deformation of the caulked portion 9 due to the above-described causes, an annular concave groove into which the caulked portion 9 can enter is formed on the stepped surface 19 of the drive shaft 16, and the stepped surface 19 and the inner ring are formed. Although it is conceivable to directly contact the inner end surface of the constant velocity joint 3b, in this case, since the shape of the step portion 18 of the constant velocity joint 15 becomes complicated, the manufacturing cost of this constant velocity joint increases. Not preferred. In view of such circumstances, the wheel supporting hub unit of the present invention has been invented to prevent deformation of the caulked portion without complicating the shape of the constant velocity joint 15.

[0009]

The hub unit for supporting a wheel according to the present invention comprises a driving shaft which forms a driving member together with a constant velocity joint, similarly to the conventional hub unit for supporting a wheel shown in FIG. A hub that is rotated when used,
A flange provided on the outer peripheral surface of the outer end portion of the hub for supporting and fixing wheels to the hub, and a second flange formed on the outer peripheral surface of the intermediate portion of the hub directly or through an inner ring separate from the hub. One inner raceway, a step formed at the inner end of the hub, the outer diameter of which is smaller than the portion forming the first inner raceway, and a second inner raceway on the outer peripheral surface An inner ring that is externally fitted to the step portion, and a first outer ring raceway facing the first inner raceway and a second outer raceway facing the second inner raceway on the inner peripheral surface, An outer ring that does not rotate during use, a mounting portion provided on the outer peripheral surface of the outer ring, and the first and second inner raceways and the first and second outer raceways to mount the outer race on a suspension device. A plurality of rolling elements are provided between them. The inner ring externally fitted to the step portion is formed by caulking and expanding a cylindrical portion formed at the inner end of the hub at a portion protruding from the inner ring externally fitted to the step portion in a radially outward direction. Thus, it is fixed to the hub in a state where it is pressed toward the step surface of the step portion. Further, the hub has an outer end face on an inner end face of a nut screwed to the tip end of the drive shaft, and an inner end face of the caulked portion on a step face of a step formed on the inner end of the drive shaft. The nut is tightened in the abutted state, so that the nut is connected and fixed to the drive shaft.

[0010] In particular, in the wheel supporting hub unit of the present invention, the drive end is provided on the inner end surface of the caulked portion which is in contact with the step surface of the step formed on the inner end of the drive shaft. A flat surface is provided on the inner end of the shaft, the surface being freely contactable with the step surface of the step portion. More preferably, at least a part of the flat surface (the portion closer to the outer periphery) is positioned diametrically outward from the inner peripheral surface of the inner race fitted to the step of the hub.

[0011]

The operation of the wheel supporting hub unit of the present invention configured as described above to rotatably support the wheel with respect to the suspension device itself is the same as the conventional wheel supporting hub shown in FIGS. Same as unit. In particular, according to the wheel supporting hub unit of the present invention, the hub constituting the wheel supporting hub unit and the driving shaft constituting the driving member are screwed and tightened with the nut provided at the tip of the driving shaft. In this case, the inner end surface of the caulked portion comes into surface contact with the step surface of the step formed at the base end of the drive shaft. Therefore, the surface pressure applied to the inner end surface of the caulked portion based on the tightening force of the nut can be reduced.

Further, at least a part of the flat surface formed on the inner end surface of the caulked portion (outer peripheral portion) is positioned diametrically outward of the inner peripheral surface of the inner race fitted to the step of the hub. In this case, the portion where the flat surface is formed at the portion closer to the outer periphery of the caulked portion by the axial load applied to the caulked portion based on the tightening of the nut is formed between the inner end surface of the inner race and the step surface. Between them in the axial direction. In this state, only the compressive load is applied to the outer peripheral portion of the caulked portion, so that the axial load can be effectively supported. Therefore, even when a large axial load is applied to the inner end surface of the caulked portion based on the tightening of the nut, the caulked portion hardly undergoes plastic deformation. Note that, as described above, a part of the flat surface formed on the inner end surface of the caulked portion is not positioned diametrically outward than the inner peripheral surface of the inner ring fitted to the step portion of the hub, and this flat surface is When the entirety is positioned diametrically inward from the inner peripheral surface of the inner race, bending stress is generated at the inner end of the hub due to the tightening of the nut. Then, based on the bending stress, the swaged portion formed at the inner end of the hub may be plastically deformed. For this reason, when practicing the present invention, it is preferable that at least a part of the flat surface has a diameter larger than the inner peripheral surface of the inner race (if the inner end opening of the inner race has a chamfer, the chamfer is further formed). The hub is located outward in the direction to prevent a bending stress from being generated at the inner end of the hub, so that only an axial compressive stress is applied to the inner end. If such a preferable structure is adopted, the holding strength of the inner ring by the caulked portion is reduced,
Alternatively, the nut that is screwed and tightened to the tip of the hub does not come loose. Therefore, a highly reliable wheel supporting hub unit can be provided.

[0013]

1 and 2 show a first embodiment of the present invention. The feature of the present invention is that the hub 13
The caulking portion 9a for holding down the inner ring 3b with respect to a
Nut 1 screwed into the male thread at the tip of hub 13a
The point is that the shape of the caulking portion 9a is devised so as not to be plastically deformed based on the axial load based on the tightening of the step 7. The structure and operation of the other parts are the same as those of the conventional structure shown in FIG. 5 described above. Therefore, duplicate description will be omitted or simplified, and the following description will focus on features of the present invention.

In order to couple and fix the inner race 3b to the inner end of the hub 13a, the inner end face of the caulking portion 9a formed at the inner end of the hub 13a is subjected to coining or turning. An annular flat surface 21 perpendicular to the center axis of the hub 13a is formed. Such an annular flat surface 21 has at least a part (a portion closer to the outer periphery) of the flat surface 21 diametrically outer than the inner peripheral surface of the inner ring 3b fitted to the step portion 7 of the hub 13a. It is formed in the state where it is located at. More preferably, the flat surface 21
And a flat surface 23 formed on the inner end surface of the inner ring 3b,
They overlap one another in the axial direction. In addition, these two flat surfaces 2
1, 23 are parallel to each other. And the hub 13
a and a drive shaft 16 that constitutes a drive member together with the constant velocity joint 15, the base end of the drive shaft 16 is attached to a flat annular surface 21 that is the inner end surface of the caulking portion 9 a. In other words, the stepped surface 19 of the step 18 formed on the shoulder of the constant velocity John Int 15 is abutted. And
In this state, the nut 17 screwed to the male screw portion at the tip end of the drive shaft 16 is tightened, so that the nut 17
The hub 13a is sandwiched between the step 13 and the step portion 18.

The function of supporting the wheel rotatably with respect to the suspension device by the wheel supporting hub unit of the present embodiment configured as described above is the same as the conventional wheel supporting hub unit shown in FIG. Same as 1a. Particularly, in the case of the wheel supporting hub unit of the present embodiment, when the hub 13a and the drive shaft 16 are coupled as described above, the step formed on the inner end surface of the caulking portion 9a and the base end of the drive shaft 16 is performed. The stepped surface 19 of 18 comes into surface contact over the entire circumference. Therefore, the nut 1
7, the surface pressure applied to the inner end face of the caulked portion 9a can be reduced. Further, the axial load applied to the caulked portion 9a based on the tightening of the nut 17 is applied to the portion of the annular flat surface 21 that is located diametrically outward from the inner peripheral surface of the inner ring 3b. By sandwiching between the flat surface 23 formed on the inner end surface of the inner ring 3b that has been subjected to hardening treatment such as quenching and the step surface 19, the bearing can be effectively supported. For this reason, the caulking portion 9a
Even when a large axial load is applied due to the tightening of the nut 17, the caulked portion 9a hardly undergoes plastic deformation. Therefore, the inner ring 3b by the caulking portion 9a
Of the hub 13a, and the nut 17 screwed and tightened to the tip of the hub 13a is not loosened. As a result, a highly reliable wheel supporting hub unit can be provided.

The portion of the above-mentioned annular flat surface 21 that is located diametrically outward from the inner peripheral surface of the inner ring 3b (the portion of the annular flat surface 21 closer to the outer periphery) is the nut 17 In order to more effectively support the axial load applied to the caulked portion 9a based on the tightening of the above, it is preferable to form as large as possible. For this reason, in the case of this example, most of the above-mentioned annular flat surface 21 except for a part close to the inner periphery is located radially outward of the inner peripheral surface of the inner ring 3b. . Also, in the case of the wheel supporting hub unit of the present embodiment, similarly to the case of the conventional wheel supporting hub unit 1 shown in FIG. 4, the outer inner raceway 11 (the first inner raceway 11) provided on the outer peripheral surface of the hub 13a. Inner ring track) of the hub 13
Instead of being formed directly on the outer peripheral surface of the intermediate portion of a, it may be formed via a separate inner ring 3a (see FIG. 3).

FIG. 3 shows a second embodiment of the present invention.
An example is shown. In the case of this example, the spacer ring 22 is externally fitted to a portion of the inner end of the hub 13a projecting inward from the inner end surface of the inner ring 3b externally fitted to the hub 13a. Then, the cylindrical portion 8 existing inside the spacer ring 22 at the inner end portion of the hub 13a is diametrically outwardly expanded to hold the spacer ring 22 toward the inner end surface of the inner ring 3b. The inner ring 3b is fixedly connected to the hub 13a. In the case of this example, by providing such a spacer ring 22, even when the caulking strength when caulking and expanding the cylindrical portion 8 is sufficiently increased, the inner ring 3 b is elastically deformed radially outward. Preventing.

That is, in the case of this embodiment, the radially outward force applied when the cylindrical portion 8 is swaged is received by the spacer ring 22 fitted to the hub 13a. Therefore, it is possible to prevent the diameter of the inner ring 3b from changing with the work of caulking and widening the cylindrical portion 8. In the case of this example, the swaged portion 9a is formed based on the tightening of the nut 17 (FIG. 1).
Of the annular flat surface 21 formed on the inner end surface of the caulked portion 9a, the portion existing diametrically outward from the inner peripheral surface of the inner ring 3b, and hardening due to quenching or the like. The spacer is effectively supported at a portion between the spacer and the inner end surface of the treated spacer 22. Spacer 2
The configuration and operation other than the provision of 2 are the same as those of the first example described above.

[0019]

Since the wheel supporting hub unit of the present invention is constructed and operates as described above, the caulking portion for holding down the inner ring against the hub is plastically deformed based on the tightening of the nut. To prevent the nut from loosening. Therefore, a highly reliable wheel supporting hub unit can be provided.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a view similar to FIG. 2, showing a second example of the embodiment of the present invention;

FIG. 4 is a sectional view showing a wheel supporting hub unit for a driven wheel as a first example of a conventional structure.

FIG. 5 is a cross-sectional view showing a wheel supporting hub unit for driving wheels according to a second embodiment of the present invention.

FIG. 6 is an enlarged view of a portion A in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Wheel support hub unit 2 Hub 3a, 3b Inner ring 4 Outer ring 5 Rolling element 6 Flange 7 Step 8 Cylindrical part 9, 9a Caulking part 10 Outer ring raceway 11 Inner ring raceway 12 Mounting part 13, 13a Hub 14 Female spline part 15 Constant velocity joint 16 Drive shaft 17 Nut 18 Step 19 Step surface 20 Top 21 Flat surface 22 Spacer 23 Flat surface

Claims (1)

[Claims] A hub which is rotatably driven by a driving member during use; a flange provided on an outer peripheral surface of the outer end of the hub for supporting and fixing a wheel to the shaft member; and an outer peripheral surface of an intermediate portion of the hub. A first inner raceway formed directly or through an inner race separate from the hub, and an outer diameter dimension formed at an inner end portion of the hub, which is larger than a portion forming the first inner raceway. Is reduced, the inner ring is formed on the outer peripheral surface to form a second inner raceway, and the inner race is externally fitted to the step, and the first outer raceway facing the first inner raceway on the inner peripheral surface and An outer ring having a second outer ring raceway opposed to the second inner raceway and not rotating during use; an attaching portion provided on an outer peripheral surface of the outer ring to attach the outer ring to a suspension; Between the second inner raceway and the first and second outer raceways, respectively. Provided with a rolling element provided, wherein the inner ring externally fitted to the step portion has a cylindrical portion formed in a portion protruding inward from the inner ring externally fitted to the step portion at the inner end of the hub in a diametrical direction. A nut which is screwed and fixed to the hub in a state where it is pressed down toward the step surface of the step portion by a caulking portion formed by caulking and spreading outward, and the hub has an outer end surface screwed to a tip portion of the drive member. And the inner end surface of the caulked portion is in contact with the stepped surface of the step formed at the inner end portion of the drive member, and the nut is tightened in a state of being in contact with the drive member, thereby being fixedly connected to the drive member. In the wheel supporting hub unit, a step formed at the inner end of the driving member is provided at an inner end surface of the caulking portion, which is a portion that contacts a step surface of a step formed at the inner end of the driving member. It is characterized by providing a flat surface that can make surface contact with the step surface of the part For supporting the wheel hub unit.