JP6844128B2 - Hub unit - Google Patents

Description

The present invention relates to a hub unit for a vehicle that rotatably supports wheels with respect to a vehicle body.

Conventionally, a plurality of outer rings fixed to a knuckle attached to a suspension device, an inner ring member to which the wheels are attached, and an outer raceway surface formed on the outer ring and an inner raceway surface formed on the inner ring member. A hub unit with a rolling element is used to rotatably support the wheels against the vehicle body. In such a hub unit, for example, as shown in Patent Document 1, a plurality of rolling elements are incorporated by applying a preload between the outer raceway surface and the inner raceway surface. The support rigidity of the wheel is secured by this preload.

Japanese Unexamined Patent Publication No. 2014-206266

In recent years, automobiles are required to have high fuel efficiency. Since the rotational resistance of the wheel increases as the preload applied to the rolling element of the hub unit increases, it is conceivable to reduce the preload applied to the rolling element in order to improve fuel efficiency. However, if the inner diameter of the outer raceway surface is increased and the preload is decreased, the support rigidity of the wheel is lowered, which may cause rattling of the wheel and deterioration of running stability.

Therefore, an object of the present invention is to provide a hub unit capable of reducing the rotational resistance of a wheel while suppressing a decrease in the support rigidity of the wheel.

In order to achieve the above object, the present invention has a tubular portion having an outer raceway surface formed on the inner circumference, an outer ring having a fixed flange protruding outward from the tubular portion, and a wheel mounting flange on which wheels are mounted. An inner ring member having an inner raceway surface facing the outer raceway surface formed on the outer circumference, a plurality of rolling elements arranged between the outer raceway surface and the inner raceway surface, and the tubular portion of the outer ring. The fixed flange is provided so as to project outward from the tubular portion, and has a fastener for deforming the wheel so that the inner diameter in the vehicle front-rear direction becomes larger than the inner diameter in the vertical direction when mounted on the vehicle. It is composed of a plurality of projecting pieces, and bolt holes are formed in each of the plurality of projecting pieces at irregular intervals in the circumferential direction of the tubular portion, and the fastener is provided with protrusions protruding outward. The fastener has a ring shape whose inner peripheral surface is formed in an elliptical shape, and the tubular portion is press-fitted so that the protrusion faces a specific projecting piece among the plurality of projecting pieces in the axial direction. Provides a hub unit that is externally fitted to.

According to the hub unit according to the present invention, it is possible to reduce the rotational resistance of the wheel while suppressing the decrease in the support rigidity of the wheel.

It is sectional drawing which shows the state which the hub unit which concerns on 1st Embodiment of this invention is assembled to a vehicle. (A) is a figure which shows the outer ring seen from the axial direction by itself. (B) is a diagram showing a fastener. (C) is a diagram showing an outer ring to which a fastener is fitted. It is a perspective view which shows the outer ring and the fastener. It is a figure which shows the modification 1 of the fastener. It is a figure which shows the modification 2 of the fastener. It is a figure which shows the tightening tool which concerns on 2nd Embodiment.

[First Embodiment]
The first embodiment of the present invention will be described with reference to FIGS. 1 to 3. It should be noted that the embodiments described below are shown as suitable specific examples for carrying out the present invention, and there are some parts that specifically exemplify various technically preferable technical matters. , The technical scope of the present invention is not limited to this specific aspect.

(Overall configuration of hub unit)
FIG. 1 is a cross-sectional view showing a state in which the hub unit 1 according to the first embodiment of the present invention is assembled to a vehicle. In FIG. 1, a hub unit 1 mounted on a vehicle is shown together with its peripheral portion. In the present embodiment, a hub unit 1 that supports the rear wheels (driving wheels) of a front-wheel drive four-wheeled vehicle will be described as an example.

The hub unit 1 is used to rotatably support the wheels 11 together with the brake rotor 12 with respect to the knuckle 90 as a support member on the vehicle body side. The wheel 11 has a tire 112 mounted on the wheel 111. Hereinafter, in the hub unit 1, the wheel 11 side (left side in FIG. 1) is referred to as a vehicle outer side, and the opposite side (right side in FIG. 1) is referred to as a vehicle inner side.

The hub unit 1 is arranged in a double row between the outer ring 2 attached to the knuckle 90 on the vehicle inner side, the inner ring member 3 to which the wheel 111 of the wheel 11 is attached together with the brake rotor 12, and the outer ring 2 and the inner ring member 3. It is provided with a plurality of rolling elements 4. A seal member 51 is attached to the end of the outer ring 2 on the vehicle outer side. The end portion of the outer ring 2 on the vehicle inner side is closed by the cover member 52.

Further, the hub unit 1 has a magnetic encoder 61 that rotates integrally with the inner ring member 3 and a magnetic field sensor 62 arranged so as to face the magnetic encoder 61 as members for detecting the rotation speed of the wheels 11. ing. The magnetic encoder 61 has an annular magnetic member 611 and a core metal 612 for fixing the magnetic member 611 to the inner ring member 3. In the magnetic member 611, a plurality of magnetic poles having different magnetisms are alternately magnetized in the circumferential direction. The magnetic field sensor 62 is fixed to the cover member 52.

Further, the hub unit 1 has a fastener 7 that deforms the tubular portion 21 of the outer ring 2 so that the inner diameter in the vehicle front-rear direction is larger than the inner diameter in the vertical direction when mounted on the vehicle. The configuration of the fastener 7 will be described later.

The rolling elements 4 are arranged in a plurality of rows between the outer ring 2 and the inner ring member 3. Of these, the one row composed of the plurality of rolling elements 4 on the vehicle outer side is referred to as the outer side rolling element row 4a, and the other row composed of the plurality of rolling elements 4 on the vehicle inner side is referred to as the inner side rolling element row 4b. The outer side rolling element row 4a is arranged on the side farther from the fixed flange 22 than the inner side rolling element row 4b. The rolling element 4 is spherical and constitutes a double row ball bearing together with the outer ring 2 and the inner ring member 3. As the material of the rolling element 4, for example, a high carbon chrome bearing steel material “SUJ2” is used.

The outer ring 2 integrally has a cylindrical tubular portion 21 and a fixed flange 22 that projects outward from the tubular portion 21 and is attached to the knuckle 90. On the inner circumference of the tubular portion 21, a first outer raceway surface 2a for rolling the rolling element 4 of the outer side rolling element row 4a and a second outer raceway surface for rolling the rolling element 4 of the inner side rolling element row 4b. 2b and 2b are formed. The first outer raceway surface 2a is formed at the axial end of the tubular portion 21 on the vehicle outer side of the fixed flange 22. A part of the second outer raceway surface 2b is formed inside the fixed flange 22 in the radial direction.

As the material of the outer ring 2, for example, high carbon steel "S55C" is used. The first outer raceway surface 2a and the second outer raceway surface 2b are formed by grinding with a grindstone.

In this embodiment, the fixing flange 22 of the outer ring 2 is attached to the knuckle 90 by four bolts 91. In FIG. 1, two of these bolts 91 are illustrated. The bolt 91 has a shaft portion 911 having a male screw formed at the tip portion and a head portion 912, and the shaft portion 911 is inserted into a bolt hole 900 formed in the knuckle 90 to form a screw hole formed in the fixed flange 22. It is screwed into 220.

The inner ring member 3 is rotatably arranged with respect to the outer ring 2 about the rotation axis O. The central axis of the outer ring 2 coincides with the rotation axis O. On the outer circumference of the inner ring member 3, a first inner raceway surface 3a for rolling the rolling element 4 of the outer side rolling element row 4a and a second inner raceway surface 3b for rolling the rolling element 4 of the inner side rolling element row 4b. And are formed. The first inner raceway surface 3a faces the first outer raceway surface 2a of the outer ring 2, and the second inner raceway surface 3b faces the second outer raceway surface 2b of the outer ring 2. The rolling element 4 of the outer side rolling element row 4a is arranged between the first inner raceway surface 3a and the first outer raceway surface 2a, and the rolling element 4 of the inner side rolling element row 4b is the second inner raceway surface 3b. It is arranged between and the second outer raceway surface 2b.

In the present embodiment, the inner ring member 3 is composed of a hub ring 31 and an annular inner ring 32. The hub wheel 31 integrally has a wheel mounting flange 311 to which the wheel 11 is mounted, a body portion 313 arranged inside the outer ring 2, and a connecting portion 312 connecting the wheel mounting flange 311 and the body portion 313. ing. The wheel mounting flange 311 is formed with a plurality of press-fitting holes 310 into which hub bolts 33 for wheel mounting are press-fitted. As the material of the hub ring 31, for example, high carbon steel "S55C" is used. As the material of the inner ring 32, for example, a high carbon chrome bearing steel material “SUJ2” is used. The core metal 612 of the magnetic encoder 61 is fitted on the outer peripheral surface of the inner ring 32 on the vehicle inner side end.

The shaft portion 331 of the hub bolt 33 is press-fitted into the press-fitting hole 310, and the head portion 332 is in contact with the end surface of the wheel mounting flange 311 on the vehicle inner side. Further, the shaft portion 331 of the hub bolt 33 is inserted into the insertion hole 110 formed in the wheel 111 of the wheel 11 and the insertion hole 120 formed in the brake rotor 12. A wheel nut 13 is screwed into the tip of the shaft portion 331.

The body portion 313 has a large diameter portion 314 on the wheel mounting flange 311 side and a small diameter portion 315 on the side opposite to the wheel mounting flange 311 side. A first inner raceway surface 3a is formed on the outer peripheral surface of the large diameter portion 314. An inner ring 32 is fitted on the outer peripheral surface of the small diameter portion 315. The inner ring 32 is fixed to the hub ring 31 by a crimping portion 315a in which a part of the small diameter portion 315 is plastically deformed. A second inner raceway surface 3b is formed on the outer peripheral surface of the inner ring 32. Preload is applied to the rolling elements 4 of the outer cartwheel row 4a and the inner cartwheel row 4b by forming the crimping portion 315a.

The plurality of rolling elements 4 in the outer side rolling element row 4a are rotatably held by the first cage 43. The plurality of cartwheels 4 in the inner cartwheel row 4b are rotatably held by the second cage 44. The first cage 43 holds the plurality of cartwheels 4 of the outer cartwheel row 4a at equal intervals, and the second cage 44 holds the plurality of cartwheels 4 of the inner cartwheel train 4b at equal intervals. doing.

The rolling elements 4 in the outer side rolling element row 4a and the rolling elements 4 in the inner side rolling element row 4b may have the same diameter (ball diameter) or may be different. Further, the number of rolling elements 4 in the outer side rolling element row 4a and the number of rolling elements 4 in the inner side rolling element row 4b may be the same or different. Further, in the present embodiment, the inner ring member 3 has one inner ring 32, but the present invention is not limited to this, and the inner ring member 3 has two inner rings arranged in the axial direction, and one of the inner rings has a first inner ring. 1 The inner raceway surface 3a may be formed, and the second inner raceway surface 3b may be formed on the other inner ring.

FIG. 2A is a diagram showing the outer ring 2 as a single unit as viewed in the axial direction from the vehicle outer side. (B) is a diagram showing a state in which the fastener 7 is viewed from the axial direction. (C) is a diagram showing an outer ring 2 in which a fastener 7 is fitted onto a tubular portion 21. FIG. 3 is a perspective view showing the outer ring 2 and the fastener 7.

The fixed flange 22 of the outer ring 2 is composed of first to fourth projecting pieces 221 to 224 provided so as to project outward from the tubular portion 21. Bolt holes 220 are formed in the first to fourth projecting pieces 221 to 224, respectively. The distance between the bolt hole 220 of the first projecting piece 221 and the bolt hole 220 of the second projecting piece 222, and the bolt hole 220 of the third projecting piece 223 and the bolt hole of the fourth projecting piece 224. The distance from the 220 is the distance between the bolt hole 220 of the first projecting piece 221 and the bolt hole 220 of the third projecting piece 223, and the distance between the bolt hole 220 and the fourth projecting piece 222 of the second projecting piece 222. It is wider than the distance between the piece 224 and the bolt hole 220. That is, the four bolt holes 220 of the fixed flange 22 are provided at irregular intervals in the circumferential direction of the tubular portion 21.

In FIGS. 2A to 2C, the left-right direction of the drawing corresponds to the vehicle front-rear direction (horizontal direction in the vehicle-mounted state), and the vertical direction of the drawing corresponds to the vertical direction (the upper part of the drawing corresponds to the upper side of the vertical direction). Further, in FIGS. 2A and 2C, the deepest portion (the portion having the largest inner diameter) 20 of the first outer raceway surface 2a is shown by a broken line. In the following description, the inner diameter of the first outer raceway surface 2a means the diameter of the deepest portion 20.

As shown in FIG. 2A, when the fastener 7 is not fitted on the outer peripheral surface of the outer ring 2, the first outer raceway surface 2a has an inner diameter Iv _{1 in the} vertical direction and an inner diameter Ih in the vehicle front-rear direction. ₁ is a perfect circle that is substantially equal to 1. _{Further, in the tubular portion 21, the outer diameter Ov 1 in the vertical direction and the outer diameter Oh 1 in the} vehicle front-rear direction in the portion corresponding to the outer peripheral side of the deepest portion 20 of the first outer track surface 2a are equal to each other.

The fastener 7 has a ring shape in which the inner peripheral surface 7a is formed in an elliptical shape, and is externally fitted to the tubular portion 21 by press fitting. Here, the "elliptical shape" is not limited to a regular ellipse consisting of a set of points at which the sum of the distances from the two focal points is constant, but a pseudo-ellipse having a long axis longer than the short axis and an overall convex shape. The purpose is to include the shape. It is desirable that the fastener 7 is made of metal and has a hardness higher (harder) than that of the outer ring 2. Further, as shown in FIG. 1, the fastener 7 is arranged on the outer peripheral side of the first outer raceway surface 2a. More specifically, the fastener 7 is arranged so as to cover at least a part of the outer peripheral surface of the tubular portion 21 in the range corresponding to the outer peripheral side of the first outer raceway surface 2a.

As shown in FIG. 2B, in the fastener 7, the inner diameter D ₁ of the inner peripheral surface 7a in the vertical direction is smaller than _{the inner diameter D 2 in the} vehicle front-rear direction. Further, the vertical direction of the inner diameter _{D 1} is smaller than the outer diameter Ov ₁ of the cylindrical portion 21, the inner diameter _{D 2} of the vehicle longitudinal direction is larger than the outer diameter Oh ₁ equal to or outer diameter Oh ₁ of the cylindrical portion 21. The difference between the inner diameter D _{1 of the fastener 7 in the vertical direction and the outer diameter Ov 1} of the tubular portion 21 before fitting the fastener 7 is, for example, 50 to 100 μm.

When the fastener 7 is press-fitted into the tubular portion 21 of the outer ring 2, as shown in FIG. 2C, the tubular portion 21 is compressed in the vertical direction and elastically deformed so as to extend in the front-rear direction of the vehicle. _{As a result, the inner diameter Iv 2 in} the vertical direction after deformation of the first outer track surface 2a is smaller than the inner diameter Iv _{1 in} the vertical direction before deformation, and the inner diameter Ih _{2 in} the vehicle front-rear direction after deformation is the front and rear of the vehicle before deformation. It becomes larger than the inner diameter Ih _{1 in the direction.} For the sake of clarity of explanation, in FIG. 2 (b), it exaggerated the difference between the inner diameter D ₁ and the vehicle longitudinal direction of the inner diameter D ₂ of the vertical direction. Similarly, in FIG. 2C, the difference between the _{inner diameter Iv 2} and the inner diameter Ih _{2 of the first outer raceway surface 2a is exaggerated.}

The deformation of the tubular portion 21 of the outer ring 2 suppresses a decrease in the support rigidity of the wheel 11 (the support rigidity of the inner ring member 3 with respect to the outer ring 2) while suppressing the rotation resistance of the wheel 11 (rotational resistance of the inner ring member 3 with respect to the outer ring 2). Is intended to reduce. That is, the support rigidity of the wheel 11 is mainly determined by the preload of the rolling element 4 in the vertical direction because the hub unit 1 supports the weight of the vehicle body, and the rotational resistance of the wheel 11 is the preload of the rolling element 4 in the entire circumferential direction. Determined by. Therefore, by deforming the outer ring 2 as described above, it is possible to reduce the rotational resistance of the wheel 11 while suppressing the decrease in the support rigidity of the wheel 11.

(Actions and effects of the first embodiment)
According to the first embodiment described above, the fastener 7 is externally fitted to the tubular portion 21 of the outer ring 2, so that the first outer raceway surface 2a is in front of and behind the vehicle than _{the inner diameter Iv 2 in the vertical direction.} It has an elliptical shape with a large inner diameter Ih _{2 in the direction.} This makes it possible to reduce the rotational resistance of the wheel 11 while suppressing the decrease in the support rigidity of the wheel 11. Further, in the present embodiment, the outer ring 2 is elastically deformed by the fastener 7 to make the first outer raceway surface 2a elliptical. Therefore, for example, the outer ring 2 is moved relative to the grindstone axis in an elliptical shape to form the first outer ring 2. Compared with the case where the outer raceway surface 2a is processed into an elliptical shape, its production is easier.

[Modified example of the first embodiment]
4 and 5 show fasteners 7A and 7B according to a modified example of the fastener 7. The fasteners 7A and 7B are elliptical in view of the fact that it is difficult for the fasteners 7 according to the first embodiment to relatively align the fasteners 7 and the outer ring 2 when press-fitting into the tubular portion 21. This makes it easier for the operator to visually recognize the minor axis direction and the major axis direction of the shape.

In the fastener 7A according to the first modification shown in FIG. 4, both ends in the short axis direction are formed as thick portions 71 and 71, and both ends in the long axis direction are formed as thin wall portions 72 and 72, respectively. .. The radial thickness t ₁ of the thick portion 71 is thicker than the _{radial thickness t 2} of the thin portion 72.

The dimensions of these thicknesses t ₁ and t ₂ are set with a difference such that the operator can easily visually recognize the difference in thickness. When assembling the fastener 7A to the outer ring 2, for example, the thick portion 71 of the fastener 7A is aligned with the central portion of the portion where the distance between the four bolt holes 220 of the fixing flange 22 of the outer ring 2 is wide, and the fastener 7A is press-fitted. To do. As described above, since the four bolt holes 220 of the fixed flange 22 are provided at irregular intervals in the circumferential direction of the tubular portion 21, the outer ring 2 and the fastener 7A can be easily aligned. is there.

_{The thickness t 1} in the minor axis direction may be thinner than the thickness t _{2 in the major axis direction.} That is, it is sufficient that at least one portion in the circumferential direction has a portion having a thickness different from that of the other portion.

The fastener 7B according to the modified example 2 shown in FIG. 5 is provided with protrusions 73 and 73 protruding outward at two locations in the circumferential direction. In the illustrated example of FIG. 5, the protrusion 73 is triangular, but the shape of the protrusion 73 is not limited to this, and can be various shapes such as a quadrangular shape and a cylindrical shape. Further, the size of the protrusion 73 can be changed as appropriate.

When assembling the fastener 7B to the outer ring 2, for example, the first protruding piece 221 and one protrusion 73 of the fixed flange 22 of the outer ring 2 face each other in the axial direction, and the second protruding piece 222 and the other protrusion The relative positions of the fastener 7B and the outer ring 2 are aligned so that 73 faces in the axial direction. Thereby, the outer ring 2 and the fastener 7B can be easily aligned. Then, after this alignment, the fastener 7B is press-fitted.

[Second Embodiment]
Next, the fastener 8 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram showing a part of the fastener 8 according to the second embodiment broken. Similar to the fastener 7 according to the first embodiment, the fastener 8 is fitted onto the tubular portion 21 of the outer ring 2 and tightens the tubular portion 21 in the vertical direction (vertical direction) in the mounted state on the vehicle. ..

The fastener 8 is a pair of bolts that fasten the first and second divided bodies 81, 82 that sandwich the tubular portion 21 of the outer ring 2 in the vertical direction when mounted on the vehicle, and these divided bodies 81, 82. Has 83. In the outer ring 2, the tubular portion 21 is compressed in the vertical direction when the first and second divided bodies 81 and 82 approach each other by the tightening force of the bolt 83. In FIG. 6, the vertical direction of the drawing corresponds to the vertical direction in the vehicle-mounted state, and the left-right direction of the drawing corresponds to the vehicle front-rear direction in the vehicle-mounted state.

The first divided body 81 has a semicircular arc portion 810 and fastening portions 811 and 811 provided at both ends of the arc portion 810, respectively. Each fastening portion 811 is formed with a bolt insertion hole 811a through which the shaft portion 831 of the bolt 83 is inserted. The second divided body 82 has a semicircular arc portion 820 and fastening portions 821 and 821 provided at both ends of the arc portion 820, respectively. Each fastening portion 821 is formed with a screw hole 812a into which a male screw formed in the shaft portion 831 of the bolt 83 is screwed.

The fastener 8 has an annular shape as a whole when the first divided body 81 and the second divided body 82 are fastened by the bolt 83. And the central portion 810a of the arc portion 810 of the first split body 81, spacing _{D 3} between the central portion 820a of the arc portion 820 of the second split body 82, a state where the bolt 83 is not tightened (Figure 6 _{In the state shown), it is larger than the vertical outer diameter Ov 1} (see FIG. 2A) of the cylinder 21 of the outer ring 2, and smaller than _{the outer diameter Ov 1} of the cylinder 21 when the bolt 83 is tightened. Become.

When the bolt 83 is not tightened, a gap S is formed between the fastening portions 811 and 811 of the first split body 81 and the fastening portions 821 and 821 of the second split body 82, and the bolt 83 is tightened. When it is inserted, the gap S is closed and the fastening portions 811 and 811 of the first split body 81 and the fastening portions 821 and 821 of the second split body 82 come into contact with each other.

When assembling the fastener 8 to the outer ring 2, the fastener 8 is arranged on the outer circumference of the tubular portion 21 in a state where the bolt 83 is not tightened, and then the bolt 83 is tightened. As a result, the tubular portion 21 is compressed in the vertical direction and deformed so as to extend in the front-rear direction of the vehicle. Therefore, as in the first embodiment, it is possible to reduce the rotational resistance of the wheel 11 while suppressing the decrease in the support rigidity of the wheel 11.

(Additional note)
Although the present invention has been described above based on the first and second embodiments, the embodiments described above do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

In addition, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention. For example, in each of the above embodiments, the case where the present invention is applied to a hub unit that supports a driven wheel to which the driving force of the driving source is not transmitted has been described as an example, but the driving force of the driving source is transmitted via the drive shaft. It is also possible to apply the present invention to a hub unit that supports the drive wheels.

1 ... Hub unit 11 ... Wheel 2 ... Outer ring 21 ... Cylinder 22 ... Fixed flange 2a ... First outer raceway surface 2b ... Second outer raceway surface 3 ... Inner ring member 3a ... First inner raceway surface 3b ... Second inner raceway surface 311 ... Wheel mounting flange 4 ... Rolling body 4a ... Outer side rolling body row 4b ... Inner side rolling body row 7, 7A, 7B, 8 ... Fastener

Claims (2)

A tubular portion having an outer raceway surface formed on the inner circumference, and an outer ring having a fixed flange protruding outward from the tubular portion.
An inner ring member having a wheel mounting flange on which wheels are mounted and having an inner raceway surface facing the outer raceway surface formed on the outer circumference.
A plurality of rolling elements arranged between the outer raceway surface and the inner raceway surface,
It has a fastener that deforms the tubular portion of the outer ring so that the inner diameter in the vehicle front-rear direction is larger than the inner diameter in the vertical direction when mounted on the vehicle.
The fixed flange is composed of a plurality of projecting pieces provided so as to project outward from the tubular portion, and bolt holes are formed in each of the plurality of projecting pieces at irregular intervals in the circumferential direction of the tubular portion. ,
The fastener is provided with a protrusion protruding outward.
The fastener has a ring shape whose inner peripheral surface is formed in an elliptical shape, and the protrusion is press-fitted into the tubular portion so as to face a specific projecting piece among the plurality of projecting pieces in the axial direction. Fitted,
Hub unit. The plurality of rolling elements are arranged in a double row between the outer ring and the inner ring member.
A pair of outer raceway surfaces for rolling the plurality of rolling elements in one row and the other row of the double row are formed on the inner circumference of the tubular portion of the outer ring.
The fastener is arranged on the outer peripheral side of the outer raceway surface that rolls the plurality of rolling elements in the row far from the fixed flange in the one row and the other row.
The hub unit according to claim 1.

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