JP2023137972A - Hub unit bearing and method for assembling the same - Google Patents

Abstract

To realize a third-generation hub unit bearing that can reduce costs and rotation torque.SOLUTION: A hub unit bearing 1 comprises an outer ring 2, a hub 3, rolling elements 4a, 4b, and an outside sealing member 5 that closes an axially outside opening part of an internal space 26. The hub 3 is composed of: a hub ring 13 having an axially outside inner ring raceway 15a on its outer peripheral surface and a rotating flange 16 in a portion located axially outward with respect to the outer ring 2; and an inner ring 15 having an axially inside inner ring raceway 15b on the outer peripheral surface. The outside sealing member 5 is a combined seal ring comprising: a circular ring-shaped outside first seal ring 29 arranged so as to face an external space 28 and supported by the hub ring 13; and a circular ring-shaped outside second seal ring 30 arranged so as to face the internal space 26 and supported by the outer ring 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hub unit bearing and a method for assembling the same.

In single-row deep groove ball bearings, as disclosed in Japanese Unexamined Patent Publication No. 2005-163900 (Patent Document 1), a so-called plate seal is used to seal the internal space in which the balls are arranged from the external space. A circular seal ring is used. The seal ring is made up of a core metal and an elastic material reinforced by the core metal, and an elastic locking part provided on the peripheral edge of one radial side of the elastic material is connected to the outer ring and the inner ring. The lip is fixed to the circumferential surface of one of the members of the outer ring and the inner ring, and a lip provided at the circumferential edge of the other radial side of the elastic material is slidably contacted with the circumferential surface of the other member of the outer ring and the inner ring. have.

Since the circular seal ring having the above-mentioned configuration has a small axial width dimension, the degree of machining of the core metal can be reduced, and the shape of the mold for vulcanizing and adhering the elastic material to the core metal can be reduced. Since the shape is simple, manufacturing costs can be reduced. Moreover, the circular seal ring can suppress sealing torque to a lower level than a sealing member consisting of a seal ring having a plurality of seal lips and a slinger. Under these circumstances, circular seal rings are widely used in bearings such as single-row deep groove ball bearings.

On the other hand, hub unit bearings, which rotatably support automobile wheels relative to suspension systems, are used in environments where they are directly splashed with muddy water, so they have a higher level of sealing performance than single-row deep groove ball bearings. is required. Therefore, it has been considered to seal the internal space from the external space using a combination seal ring configured by combining two circular seal rings in the hub unit bearing.

FIG. 13 shows a hub unit bearing 100 described in Japanese Patent Application Publication No. 2019-206990 (Patent Document 2).

The hub unit bearing 100 is a so-called first generation hub unit bearing, and includes an outer ring 101, a pair of inner rings 102, a plurality of balls 103, an outer sealing member 104, and an inner sealing member 105.

The outer ring 101 has a double row outer ring raceway 106 on its inner peripheral surface. Each of the pair of inner rings 102 has an inner ring raceway 107 on its outer peripheral surface. The pair of inner rings 102 are arranged radially inside the outer ring 101 and coaxially with the outer ring 101, with their small diameter side end surfaces abutting each other. A plurality of balls 103 are arranged in each row between a double-row outer ring raceway 106 and a double-row inner ring raceway 107 and spaced apart in the circumferential direction, and are rolled by a cage 108 in each row. freely held.

When assembled to a vehicle, the outer ring 101 is fitted and fixed to a knuckle constituting a suspension device (not shown). On the other hand, the pair of inner rings 102 are externally fitted and fixed to a hub axle (not shown) having a hub flange for supporting wheels, thereby forming a hub.

The outer sealing member 104 closes an axially outer opening of an internal space 109 that exists between the inner circumferential surface of the outer ring 101 and the outer circumferential surface of the inner ring 102 . In contrast, the inner sealing member 105 closes the axially inner opening of the inner space 109. Thus, each of the outer sealing member 104 and the inner sealing member 105 seals the interior space 109 from the exterior space 110.

The outer sealing member 104 includes a circular ring-shaped outer first seal ring 111 disposed facing the external space 110 and a circular ring-shaped outer second seal ring 112 disposed facing the inner space 109. This is a combination seal ring.

The inner sealing member 105 includes a circular first inner seal ring 113 disposed facing the external space 110 and a circular second inner seal ring 114 disposed facing the internal space 109. This is a combination seal ring.

Each of the outer sealing member 104 and the inner sealing member 105 is attached to the opening of the internal space 109 in a state in which the outer ring 101, the pair of inner rings 102, and the balls 103 are combined. Specifically, each of the first outer seal ring 111 and the second outer seal ring 112 elastically deforms the elastic locking portion provided at the peripheral edge of the elastic material, and closes the axially outer opening of the internal space 109. It is pushed into the section from the outside in the axial direction. Further, each of the first inner seal ring 113 and the second inner seal ring 114 elastically deforms the elastic locking portion provided at the peripheral edge of the elastic material, and the inner first seal ring 113 and the second inner seal ring 114 each have a shaft attached to the axially inner opening of the inner space 109. Pushed in from the inside.

Since the hub unit bearing 100 with the conventional structure uses a combination seal ring consisting of two seal rings each having a circular ring shape as the outer sealing member 104 and the inner sealing member 105, cost can be reduced and , the rotational torque can be reduced.

Japanese Patent Application Publication No. 2005-163900 JP2019-206990A

A combination seal ring consisting of two seal rings, each of which has a circular ring shape, is manufactured by assembling the outer ring, hub (inner ring), and rolling elements that make up the hub unit bearing, and then rotating each of the two seal rings in the axial direction. It is attached to the opening of the internal space by pushing it into the hole.

For this reason, it is considered that a combination seal ring consisting of two seal rings will be applied only to so-called first and second generation hub unit bearings that can employ the assembly method described above. Application to the outer sealing member of a so-called third generation hub unit bearing provided with a rotating flange has not been considered at all. That is, in the third generation hub unit bearing, since the rotating flange provided on the hub exists on the axially outer side of the axially outer opening of the internal space, the two pieces can be assembled using the above-mentioned assembly method. The sealing ring cannot be installed in the axially outer opening of the internal space.

For this reason, most of the outer sealing members of third-generation hub unit bearings support one seal ring with multiple lips on the outer ring, and each of the multiple lips slides into contact with the outer peripheral surface of the hub. The configuration is adopted. However, if such a configuration is adopted, the cost may increase and the rotational torque may increase compared to the case where a combination seal ring consisting of two seal rings each having a circular ring shape is used.

The present invention has been made to solve the above problems, and an object of the present invention is to realize a third generation hub unit bearing that can reduce costs and rotational torque.

A hub unit bearing according to one aspect of the present invention includes an outer ring, a hub, rolling elements, and an outer sealing member.
The outer ring has a double-row outer ring raceway on its inner peripheral surface and does not rotate during use.
The hub has a double-row inner raceway on its outer peripheral surface and rotates during use.
A plurality of the rolling elements are disposed between the double-row outer ring raceway and the double-row inner ring raceway in a rotatable manner for each row.
The outer sealing member closes an axially outer opening of an internal space that exists between an inner circumferential surface of the outer ring and an outer circumferential surface of the hub.
The hub includes a hub ring having an axially outer inner ring raceway of the double row inner ring raceway on an outer circumferential surface and a rotating flange at a portion located axially outer than the outer ring; and an inner ring having an axially inner inner ring raceway of the inner ring raceways of the row on its outer peripheral surface.
The outer sealing member includes a first outer seal ring having a circular ring shape, which is disposed facing the external space, and supported by the hub ring, and a first outer seal ring, which is disposed facing the inner space, and has a circular ring shape, and which is disposed facing the inner space, and which is supported by the hub ring. This is a combination seal ring consisting of a second outer seal ring having a circular ring shape and supported by a second outer seal ring.

The hub unit bearing according to one aspect of the present invention further includes an inner sealing member that closes an axially inner opening of the internal space, and the inner sealing member has a circular ring shape disposed facing the external space. The combination seal ring may be made up of a first inner seal ring having a circular ring shape and a second inner seal ring having a circular ring shape and disposed facing the inner space.

In the hub unit bearing according to one aspect of the present invention, the second outer seal ring may include a conductive elastic material that electrically connects the outer ring and the hub.
In the hub unit bearing according to one aspect of the present invention, when the inner sealing member includes the first inner seal ring and the second inner seal ring, the second inner seal ring is connected to the outer ring and the hub. It is also possible to include an elastic material with conductivity that provides electrical continuity between the two.

In the hub unit bearing according to one aspect of the present invention, conductive grease can be filled between the first outer seal ring and the second outer seal ring.
In the hub unit bearing according to one aspect of the present invention, when the inner sealing member includes the first inner seal ring and the second inner seal ring, the first inner seal ring and the second inner seal ring are provided. Conductive grease can also be filled between the two.

A method for assembling a hub unit bearing according to an aspect of the present invention is a method for assembling the hub unit bearing according to an aspect of the present invention, in which the rotary flange and the axially outer portion of the outer circumferential surface of the hub ring are a step of supporting the first outer seal ring between the outer ring raceway and the outer ring raceway; and a step of supporting the outer first seal ring between the outer ring raceway and the outer ring raceway; The method includes a step of supporting a seal ring, and a step of inserting the hub ring on which the first outer seal ring is supported into the radially inner side of the outer ring on which the second outer seal ring is supported.

According to the hub unit bearing according to one aspect of the present invention, although it has a so-called third generation structure, it is possible to reduce costs and reduce rotational torque.

FIG. 1 is a half sectional view showing a third generation hub unit bearing according to a first example of the embodiment. FIG. 2 is an enlarged view of section A in FIG. FIG. 3 is a cross-sectional view for explaining a method of assembling a hub unit bearing regarding the first example of the embodiment. FIG. 4 is a diagram corresponding to FIG. 2, showing a second example of the embodiment. FIG. 5 is a diagram corresponding to FIG. 2, showing a fourth example of the embodiment. FIG. 6 is a diagram corresponding to FIG. 2, showing a fifth example of the embodiment. FIG. 7 is a diagram corresponding to FIG. 2, showing a modification of the fifth example of the embodiment. FIG. 8 is a diagram corresponding to FIG. 1, showing a sixth example of the embodiment. FIG. 9 is an enlarged view of part B in FIG. 8. FIG. 10 is a diagram corresponding to FIG. 9, showing a first example of a modification of the sixth example of the embodiment. FIG. 11 is a diagram corresponding to FIG. 9, showing a fourth example of a modification of the sixth example of the embodiment. FIG. 12 is a diagram corresponding to FIG. 9, showing a fifth example of a modification of the sixth example of the embodiment. FIG. 13 is a half sectional view showing a first generation hub unit bearing with a conventional structure.

[First example of embodiment]
A first example of the embodiment will be described using FIGS. 1 to 3.

[Structure of hub unit bearing]
The hub unit bearing 1 is a so-called third generation hub unit bearing of an inner ring rotating type and for a driven wheel. The hub unit bearing 1 includes an outer ring 2, a hub 3, a plurality of rolling elements 4a and 4b, an outer sealing member 5, and an inner sealing member 6.
Regarding the hub unit bearing 1, the axially outer side is the left side in FIGS. 1 to 3, which is the outer side in the width direction of the vehicle when assembled to the vehicle, and the axially inner side is the outer side in the width direction of the vehicle when assembled to the vehicle. This is the right side of FIGS. 1 to 3, which is the center side in the direction. Further, the axial direction, radial direction, and circumferential direction refer to each direction regarding the hub 3 unless otherwise specified.

The outer ring 2 is made of hard metal such as medium carbon steel and has a substantially cylindrical shape. The outer ring 2 has double-row outer ring raceways 7a and 7b on its inner circumferential surface, and has a stationary flange 8 projecting radially outward at an axially intermediate portion of its outer circumferential surface. The stationary flange 8 has support holes 9 extending in the axial direction at a plurality of locations in the circumferential direction. The outer ring 2 is supported and fixed to a suspension device, which is a member on the vehicle body side, by bolts inserted into the support holes 9, and does not rotate during use.

As shown in FIG. 2, the outer ring 2 has a tapered outer ring seal sliding surface 10 at the axially outer end of the inner peripheral surface. The outer ring seal sliding surface 10 is inclined by several degrees in a direction in which the inner diameter becomes larger toward the outer side in the axial direction. Further, the outer ring 2 has an outer ring locking groove 11 between the outer ring seal sliding surface 10 and the axially outer outer ring raceway 7a on the inner peripheral surface. The outer ring locking groove 11 is provided on the inner peripheral surface of the outer ring 2 over the entire circumference, and has a substantially rectangular cross-sectional shape. A pair of groove inner surfaces 12a and 12b forming the inner surface of the outer ring locking groove 11 have the same radial depth dimension.

The hub 3 is arranged radially inside the outer ring 2 and coaxially with the outer ring 2. A wheel and a braking rotating body constituting the wheel are fixed to the hub 3, and rotate during use. The hub 3 is formed by combining a hub ring 13 made of hard metal such as medium carbon steel and an inner ring 14 made of hard metal such as high carbon chromium steel. The hub 3 has double-row inner ring raceways 15a, 15b on a portion of its outer peripheral surface that faces the double-row outer ring raceways 7a, 7b.

The hub ring 13 is a shaft member that externally fits and holds the inner ring 14 . Since the hub unit bearing 1 of this example is for a driven wheel, the hub wheel 13 is not connected to a constant velocity joint.

The hub ring 13 has an axially outer inner ring raceway 15a at an axially intermediate portion of the outer peripheral surface. Further, the hub ring 13 has a rotating flange 16 that protrudes radially outward on a portion of the outer circumferential surface that is located axially outer than the outer ring 2, and has a rotating flange 16 that protrudes radially outward than the inner ring raceway 15a that is axially outer. It has a stepped surface 17 facing inward in the axial direction at a portion located on the inner side in the axial direction. An axially outer end surface of the inner ring 14 abuts against the stepped surface 17 as described later.

As shown in FIG. 2, the hub ring 13 has a cylindrical hub ring seal sliding contact surface 18 and a hub ring locking surface between the rotating flange 16 and the axially outer inner raceway 15a on the outer peripheral surface. It has a groove 19. The hub ring seal sliding surface 18 is provided at a portion of the outer peripheral surface of the hub ring 13 that faces the outer ring locking groove 11 in the radial direction. The hub ring seal sliding surface 18 has a constant outer diameter in the axial direction. The hub ring locking groove 19 is provided in a portion of the outer peripheral surface of the hub ring 13 that faces the outer ring seal sliding surface 10 in the radial direction. For this reason, the hub ring locking groove 19 is provided between the rotating flange 16 and the hub ring seal sliding surface 18. The hub ring locking groove 19 is provided on the outer peripheral surface of the hub ring 13 over the entire circumference, and has a substantially rectangular cross-sectional shape. A pair of groove inner surfaces 20a and 20b forming the inner surface of the hub ring locking groove 19 have the same radial depth dimension.

The hub ring 13 has a pilot portion 21 at its axially outer end. The pilot part 21 is for externally fitting the wheel and the braking rotating body with a loose fit without rattling, and has a substantially cylindrical shape.

The hub ring 13 has a fitting cylindrical part 22, in which the inner ring 14 is externally fitted, which has a smaller outer diameter than the part adjacent to the outer side in the axial direction, in a part located inward in the axial direction of the inner ring raceway 15a on the outer side in the axial direction. have Further, the hub ring 13 has a caulking portion 23 that is bent radially outward from the axially inner end of the fitting cylinder portion 22 and presses against the axially inner end surface of the inner ring 14 .

The rotating flange 16 has a substantially circular ring shape, and has mounting holes 24 that penetrate in the axial direction at a plurality of locations in the circumferential direction at a radially intermediate portion. A stud 25 is press-fitted into each of the mounting holes 24. A nut (not shown) is screwed onto the tip of the stud 25. As a result, the wheel and the braking rotating body constituting the wheel are fixed to the outside of the rotating flange 16 in the axial direction. Since the hub unit bearing 1 of this example is a so-called third generation hub unit bearing, the base end of the rotating flange 16 is adjacent to the axially outer side of the axially outer opening of the internal space 26, which will be described later. It is located. When carrying out the present invention, a female threaded hole is formed in the rotating flange, and a hub bolt is directly screwed into the female threaded hole, thereby fixing the wheel and the braking rotating body to the axially outer side of the rotating flange. good.

The inner ring 14 has an annular shape and has an axially inner inner ring raceway 15b at the axially intermediate portion of the outer peripheral surface. The inner ring 14 is externally fitted into a fitting cylinder portion 22 provided on the hub ring 13 without play. Further, the axially outer end surface of the inner ring 14 is abutted against the stepped surface 17 , and the axially inner surface of the inner ring 14 is pressed down by the caulking portion 23 . Therefore, the inner ring 14 is held between the stepped surface 17 and the caulked portion 23 from both sides in the axial direction. Thereby, the hub ring 13 and the inner ring 14 are combined to form the hub 3. Further, appropriate preload is applied to the rolling elements 4a and 4b.

An internal space 26 having an annular shape is provided between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. Rolling elements 4a and 4b are arranged in the internal space 26, and a lubricant (grease) is sealed therein.

A plurality of rolling elements 4a and 4b are rolled between the double-row outer ring raceways 7a and 7b and the double-row inner ring raceways 15a and 15b in a state in which a plurality of rolling elements are held in each row by cages 27a and 27b. It is arranged so that it can move freely. In this example, balls (steel balls) are used as the rolling elements 4a and 4b, but tapered rollers may be used instead of the balls. Further, the pitch circle diameter of the rolling element 4a on the axially outer side and the pitch circle diameter of the rolling element 4b on the axially inner side are the same, but the pitch circle diameter of the rolling element on the axially outer side and the pitch circle diameter of the rolling element 4b on the axially inner side are the same. The pitch diameters of the rolling elements can also be made different from each other.

The hub unit bearing 1 of this example is designed to prevent foreign substances such as moisture and dust from entering the internal space 26 and to prevent grease sealed in the internal space 26 from leaking outside. The opening on the outer side in the direction is closed by an outer sealing member 5, and the opening on the inner side in the axial direction of the internal space 26 is closed by an inner sealing member 6. That is, each of the outer sealing member 5 and the inner sealing member 6 seals the internal space 26 from the external space 28. Note that the external space 28 refers to the space that exists around the hub unit bearing 1.

<Outer sealing member>
As shown in FIG. 2, the outer sealing member 5 includes a ring-shaped outer first seal ring 29 disposed facing the external space 28 and a ring-shaped outer first seal ring 29 disposed facing the inner space 26. This is a combination seal ring consisting of a second seal ring 30. That is, the outer sealing member 5 is composed of two seal rings, the first outer seal ring 29 and the second outer seal ring 30 which is disposed adjacent to the first outer seal ring 29 in the axial direction.

《Outer first seal ring》
The first outer seal ring 29 includes a first outer core metal 31 having a ring shape and a first outer elastic member 32 reinforced by the first outer core metal 31, and is supported on the outer peripheral surface of the hub ring 13. ing. Therefore, the first outer seal ring 29 rotates together with the hub ring 13. The outer first seal ring 29 has a sufficiently smaller axial width than its radial width. The first outer seal ring 29 is constructed by vulcanizing and adhering the first outer elastic material 32 to the first outer metal core 31 .

The outer first core bar 31 is made by pressing a metal plate such as a cold rolled steel plate. The outer first core metal 31 has a circular base plate portion 31a, an outer diameter side cylindrical portion 31b, an inner diameter side inclined portion 31c, and an inner diameter side circular ring portion 31d.

The circular base plate portion 31a extends in the radial direction and has a circular ring shape. The circular base plate portion 31a is provided from the radially outer portion to the radially intermediate portion of the outer first core metal 31. The outer diameter side cylindrical portion 31b is provided at the radially outer end of the outer first core bar 31. The outer diameter side cylindrical portion 31b is bent at a substantially right angle from the radially outer end of the annular base portion 31a toward the axially inner side. The radially inner inclined portion 31c is provided on the radially inner side of the outer first core bar 31. The inner diameter side inclined portion 31c extends obliquely from the radially inner end of the annular base portion 31a in a direction toward the axially inner side as it goes radially inward. The inner circular ring portion 31d is provided at the radially inner end of the outer first core metal 31. The inner diameter side circular ring part 31d is arranged substantially parallel to the circular ring base plate part 31a, and is offset inward in the axial direction with respect to the circular ring base plate part 31a.

The outer first elastic member 32 is made of rubber (seal rubber) such as nitrile rubber, acrylic rubber, silicone rubber, fluororubber, ethylene propylene rubber, or hydrogenated nitrile rubber. The first outer elastic material 32 covers a portion of the surface of the first outer metal core 31 except for the inner surface in the axial direction of the annular base portion 31a. The first outer elastic member 32 has an annular inner elastic locking portion 32a at its inner peripheral edge, and a partially conical cylindrical outer lip 32b at its outer peripheral edge.

The inner circumferential elastic locking portion 32a is arranged radially inward than the inner circular ring portion 31d of the outer first core metal 31. A radially outer end of the inner elastic locking portion 32a is connected to a portion of the first outer elastic member 32 that covers the inner ring portion 31d. The inner peripheral elastic locking portion 32a has a substantially rectangular cross-sectional shape.

The outer lip 32b is disposed radially outward from the outer cylindrical portion 31b of the first outer core metal 31. The radially inner end of the outer lip 32b is connected to a portion of the first outer elastic member 32 that covers the outer circumferential surface of the outer cylindrical portion 31b. The outer circumferential lip 32b extends obliquely toward the axially outer side as it goes radially outward.

The first outer seal ring 29 engages an inner elastic locking portion 32a provided on the inner peripheral edge of the first outer elastic member 32 with a hub ring locking groove 19 provided on the outer peripheral surface of the hub ring 13. By stopping, it is supported by the hub wheel 13. In addition, in a state in which the first outer seal ring 29 is locked to the hub ring 13, the outer circumferential lip 32b provided on the outer circumferential edge of the outer first elastic member 32 is connected to the taper provided on the inner circumferential surface of the outer ring 2. It is in sliding contact with the outer ring seal sliding surface 10 over the entire circumference.

《Outer 2nd seal ring》
The second outer seal ring 30 includes a second outer core metal 33 having a ring shape and a second outer elastic member 34 reinforced by the second outer core metal 33, and is supported on the inner peripheral surface of the outer ring 2. ing. Therefore, the second outer seal ring 30 does not rotate. The outer second seal ring 30 has a sufficiently smaller axial width than its radial width. The second outer seal ring 30 is constructed by vulcanizing and adhering the second outer elastic material 34 to the second outer metal core 33.

The outer second core bar 33 is made by pressing a metal plate such as a cold rolled steel plate. The outer second core metal 33 has a circular base plate portion 33a, an outer diameter side inclined portion 33b, an outer diameter side circular ring portion 33c, and an inner diameter side inclined portion 33d.

The circular base plate portion 33a extends in the radial direction and has a circular ring shape. The circular base plate portion 33a is provided at a radially intermediate portion of the outer second core bar 33. The outer diameter side inclined portion 33b is provided on the radially outer side of the outer second core bar 33. The outer diameter side inclined portion 33b extends obliquely from the radially outer end of the annular base plate portion 33a in a direction toward the axially inner side as it goes radially outward. The outer diameter circular ring portion 33c is provided at the radially outer end of the outer second core metal 33. The outer diameter side circular ring part 33c is arranged substantially parallel to the circular ring base plate part 33a, and is offset inward in the axial direction with respect to the circular ring base plate part 33a. The inner diameter side inclined portion 33d is provided at the radially inner end of the outer second core bar 33. The radially inner inclined portion 33d extends obliquely from the radially inner end of the annular base plate portion 33a toward the axially inner side toward the radially inner side.

The outer second elastic material 34 is made of rubber (seal rubber) such as nitrile rubber, acrylic rubber, silicone rubber, fluororubber, ethylene propylene rubber, or hydrogenated nitrile rubber. The second outer elastic material 34 covers the surface of the second outer metal core 33 except for the inner surface in the axial direction of the annular base portion 33a. The second outer elastic member 34 has an annular outer elastic locking portion 34a on the outer periphery and a partially conical inner lip 34b on the inner periphery.

The outer circumferential elastic locking portion 34a is arranged radially outward from the outer circular ring portion 33c of the outer second core metal 33. A radially inner end portion of the outer circumferential elastic locking portion 34a is connected to a portion of the outer second elastic member 34 that covers the outer circumferential ring portion 33c. The outer peripheral elastic locking portion 34a has a substantially rectangular cross-sectional shape.

The inner circumferential lip 34b is arranged radially inward of the inner radially inclined portion 33d of the outer second core metal 33. The radially outer end of the inner lip 34b is connected to a portion of the second outer elastic member 34 that covers the inner radially inclined portion 33d. The inner circumferential lip 34b extends obliquely toward the axially outer side as it goes radially inward.

The second outer seal ring 30 locks the outer elastic locking portion 34a provided on the outer peripheral edge of the second outer elastic member 34 in the outer ring locking groove 11 provided on the inner peripheral surface of the outer ring 2. Thus, it is supported by the outer ring 2. In addition, while the second outer seal ring 30 is locked to the outer ring 2, the inner lip 34b provided on the inner peripheral edge of the second outer elastic member 34 is connected to the inner lip 34b provided on the outer peripheral surface of the hub ring 13. It is brought into sliding contact with a planar hub ring seal sliding surface 18 over the entire circumference. In this example, such an outer sealing member 5 closes the axially outer opening of the internal space 26 .

<Inner sealing member>
The inner sealing member 6 is constituted by a cylindrical metal cover with a bottom. The inner sealing member 6 has a fitting cylinder part 35 and a bottom plate part 36.

The fitting cylindrical portion 35 has a cylindrical shape, and is internally fitted into the axially inner portion of the outer ring 2 with tight fit. The bottom plate portion 36 has a disk shape. A radially outer end of the bottom plate portion 36 is connected to an axially inner end of the fitting cylinder portion 35 . Therefore, the bottom plate portion 36 closes the axially inner end opening of the fitting cylinder portion 35. The outer peripheral edge of the bottom plate portion 36 has an abutting portion 36a formed of a folded portion.

The inner sealing member 6 is attached to the outer ring 2 by fitting the fitting cylinder part 35 into the inner part of the outer ring 2 in the axial direction by tight fitting. In this example, such an inner sealing member 6 closes the axially inner opening of the inner space 26 . The inner sealing member 6 is positioned with respect to the outer ring 2 in the axial direction by abutting the abutting portion 36a against the axially inner end surface of the outer ring 2.

[Manufacturing method of hub unit bearing]
Next, a method for assembling the hub unit bearing 1 of this example will be described with reference to FIG. 3.

In the hub unit bearing 1 of this example, since the rotating flange 16 exists on the axially outer side of the axially outer opening of the internal space 26, after the outer ring 2, the hub 3, and the rolling elements 4a, 4b are assembled, The outer sealing member 5 cannot be fitted into the axially outer opening of the internal space 26 by pushing it axially. Therefore, in this example, in order to attach the outer sealing member 5 to the axially outer opening of the internal space 26, the following steps are provided.

<Outer first seal ring installation process>
In this example, as shown in FIG. 3A, before the hub ring 13 is inserted into the radially inner side of the outer ring 2, the outer first seal ring 29 is supported against the outer peripheral surface of the hub ring 13. put. That is, while elastically deforming the inner circumferential side elastic locking portion 32a provided on the inner circumferential edge, the outer first seal ring 29 is attached to the fitting cylinder of the hub ring 13 with respect to the hub ring 13 before being combined with the inner ring 14. Push in in the axial direction from the part 22 side. Then, the inner peripheral side elastic locking portion 32a is locked in the hub wheel locking groove 19 provided on the outer peripheral surface of the hub wheel 13. Thereby, the first outer seal ring 29 is supported against the outer peripheral surface of the hub ring 13.

<Outer second seal ring installation process>
Further, as shown in FIG. 3B, before the hub ring 13 is inserted radially inside the outer ring 2, the outer second seal ring 30 is supported against the inner peripheral surface of the outer ring 2. That is, the rolling elements 4a, 4b are held in the retainers 27a, 27b, and are arranged radially inward of the double-row outer ring raceways 7a, 7b of the outer ring 2, and the second outer seal ring 30 is attached to the outer peripheral edge. While elastically deforming the outer circumferential elastic locking portion 34a provided at the outer ring seal, the outer ring 2 is pushed into the outer ring 2 from the outer ring seal sliding surface 10 side in the axial direction. Then, the outer peripheral side elastic locking portion 34a is locked in the outer ring locking groove 11 provided on the inner peripheral surface of the outer ring 2. Thereby, the second outer seal ring 30 is supported against the inner circumferential surface of the outer ring 2.
Note that the order of the steps for attaching the first outer seal ring 29 and the second outer seal ring 30 is not particularly limited, and the order may be changed or the steps may be performed at the same time unless a contradiction occurs. can.

<Assembling process of outer ring and hub ring>
In this example, after the above-described first outer seal ring attachment step and second outer seal ring attachment step, as shown in FIG. 3C, the hub wheel 13 with the first outer seal ring 29 supported is A step of inserting the second outer seal ring 30 into the radially inner side of the supported outer ring 2 is performed. Specifically, it is inserted into the radially inner side of the outer ring 2 from the axially outer opening of the outer ring 2 with the axially inner end of the hub ring 13 leading. Then, the outer lip 32b provided on the outer peripheral edge of the first outer seal ring 29 is brought into sliding contact with the outer ring seal sliding surface 10 provided on the inner peripheral surface of the outer ring 2, and the second outer seal ring An inner peripheral lip 34b provided on the inner peripheral edge of the hub ring 13 is brought into sliding contact with a hub ring seal sliding surface 18 provided on the outer peripheral surface of the hub ring 13.

In this example, as shown in FIG. 2, the axially outer surface of the tip of the inner circumferential lip 34b provided on the outer second seal ring 30 is inclined in the direction axially inward as it goes radially inward. A tapered surface 34b1 is formed. Therefore, when inserting the hub ring 13 inside the outer ring 2 in the radial direction, the axially outer surface of the tip of the inner lip 34b is located on the axially outer inner ring track of the outer circumferential surface of the hub ring 13. Even if the inner circumferential lip 34b is caught in the groove shoulder 37 connecting the hub ring seal sliding surface 15a and the hub ring seal sliding surface 18, the inner circumferential lip 34b can be prevented from being reversed in the axial direction.

After inserting the hub ring 13 inside the outer ring 2 in the radial direction as described above, the inner ring 14 is externally fitted into the fitting cylinder part 22 provided on the axially inner side of the hub ring 13, and then the fitting is performed. A caulking portion 23 is formed at the axially inner end of the joint tube portion 22 . Thereafter, the inner sealing member 6 is attached to the axially inner side of the outer ring 2 to close the axially inner opening of the internal space 26.

According to the hub unit bearing 1 of this example as described above, although it has a so-called third generation structure, it is possible to reduce the cost and to reduce the rotational torque.
That is, in this example, an assembly method is adopted in which the hub ring 13 supporting the first outer seal ring 29 is inserted radially inside the outer ring 2 supporting the second outer seal ring 30. Therefore, although the hub unit bearing 1 of this example has a so-called third generation structure, the outer sealing members 5 that close the axially outer opening of the internal space 26 are provided with outer first outer sealing members each having a circular ring shape. A combination seal ring consisting of seal ring 29 and outer second seal ring 30 can be used. Here, since each of the first outer seal ring 29 and the second outer seal ring 30 has a sufficiently smaller axial width dimension than the radial width dimension, the outer first cored metal 31 and the outer second cored metal 33, and the shape of the mold for vulcanizing and adhering the first outer elastic member 32 and the second outer elastic member 34 can be of a simple shape, so manufacturing costs can be kept low. Further, since each of the first outer seal ring 29 and the second outer seal ring 30 includes only one lip 32b and one lip 34b, the sealing torque can be kept low. Therefore, according to the hub unit bearing 1 of this example, it is possible to reduce the cost and reduce the rotational torque compared to the case where one seal ring with a plurality of lips is used as the outer sealing member. It is possible to reduce the

[Second example of embodiment]
A second example of the embodiment will be described using FIG. 4.

In this example, only the structure of the outer sealing member 5a is changed from the structure of the first example of the embodiment.

Specifically, as the second outer seal ring 30a constituting the outer seal member 5a, one having two lips is used. That is, the second outer seal ring 30a includes a side lip 34c in addition to the inner lip 34b. The side lip 34c is provided on the axially outer surface of the radially inner portion of the second outer elastic member 34. The front half of the side lip 34c has a partially conical cylindrical shape, and extends obliquely toward the outside in the radial direction as it goes toward the outside in the axial direction. The tip of the side lip 34c is in sliding contact over the entire circumference with the inner surface in the axial direction of the annular base portion 31a of the outer first metal core 31 constituting the outer first seal ring 29.

In this example as described above, since the second outer seal ring 30a includes the side lip 34c in addition to the inner lip 34b, it is possible to improve the sealing performance of the outer sealing member 5a. .
Other configurations and effects are the same as in the first example of the embodiment.

[Third example of embodiment]
A third example of the embodiment will be described using FIG. 2 used in the first example of the embodiment. In this example, only the material of the second outer elastic member 34 constituting the second outer seal ring 30 is changed from the structure of the first example of the embodiment. The material of the first outer elastic member 32 constituting the first outer seal ring 29 is the same as the structure of the first example of the embodiment.

In this example, the outer second elastic member 34 is made of conductive rubber. Specifically, the conductive rubber used is a rubber material in which conductive additives such as conductive particles and conductive fibers are kneaded. As the rubber material, in addition to nitrile rubber, acrylic rubber, fluororubber, silicone rubber, etc. can be used. As the conductive particles, in addition to carbon black, conductive metal oxides such as graphite, indium tin oxide, and antimony tin oxide can be used. Further, as the conductive fiber, carbon fiber (carbon fiber, carbon nanotube), etc. can be used.

In this example as described above, the outer ring 2 and the hub ring 13 are electrically connected through the outer second elastic member 34 that is in direct contact with the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub ring 13. be able to. Specifically, current can be intermittently passed between the outer ring 2 and the hub ring 13 by repeating charging and discharging due to dielectric breakdown. In this example, unlike the structure in which the outer ring and the hub ring are electrically connected through a metal core, there is no need to pass electricity through the vulcanized adhesive, which is an insulator, so that the conductivity can be improved. Therefore, static electricity charged on the vehicle body can be efficiently released to the tire side through the hub unit bearing 1 (see FIG. 1). Furthermore, in this example, the first outer elastic material 32 of the first outer seal ring 29, which is subjected to more severe muddy water conditions than the second outer seal ring 30, is made of normal nitrile rubber, acrylic rubber, etc., rather than conductive rubber. Since seal rubber is used, it is possible to achieve both muddy water durability and conductivity.
Other configurations and effects are the same as in the first example of the embodiment.

[Fourth example of embodiment]
A fourth example of the embodiment will be described using FIG. 5.

In this example, only the structure of the outer sealing member 5b is changed from the structure of the first example of the embodiment.

In this example, conductive grease 38 is filled between the first outer seal ring 29 and the second outer seal ring 30 that constitute the outer sealing member 5b. In addition, in FIG. 5, the conductive grease 38 is shown in a pear pattern.

As the conductive grease 38, a mixture of base oil and a thickener with a conductive material for imparting conductivity can be used.

As the base oil, those commonly used as base oils for lubricating oils can be used. For example, mineral oil-based, synthetic oil-based, or natural oil-based lubricating base oils, or mixtures thereof may be used. In addition, as the thickener, metal soaps such as metal soaps made of Li and Na, composite metal soaps selected from Li, Na, Ba, Ca, etc., and urea compounds such as diurea and polyurea are used. can. Further, as the conductive material, for example, graphite, carbon black, carbon nanotubes, fullerene, etc. can be used.

In this example as described above, the outer ring 2 and the hub ring 13 can be electrically connected through the conductive grease 38 filled between the first outer seal ring 29 and the second outer seal ring 30. Therefore, in this example, static electricity charged on the vehicle body can be efficiently released to the tire side through the hub unit bearing 1 (see FIG. 1). Note that it is also possible to establish electrical continuity between the outer ring 2 and the hub ring 13 by sealing conductive grease containing a conductive material in the internal space 26, but in this case, the aggregates of the conductive material may form on the rolling elements. Being caught between 4a and 4b and the raceway surface may cause a sudden change in rolling resistance (gritty feeling), and may also cause problems such as a tendency for conductivity to decrease with long-term use. . In this example, the outer ring 2 and the hub ring 13 can be electrically connected via the conductive grease 38 filled between the first outer seal ring 29 and the second outer seal ring 30, so that the above-mentioned problem does not occur. Nor.
Other configurations and effects are the same as in the first example of the embodiment.

[Fifth example of embodiment]
A fifth example of the embodiment will be described using FIG. 6.

In this example, the structure of the inner peripheral surface of the outer ring 2 that includes the outer ring locking groove 11a for locking the second outer seal ring 30, and the structure of the portion of the outer peripheral surface of the hub ring 13 that includes the outer ring locking groove 11a for locking the second outer seal ring 30, and Only the structure of the portion including the hub ring locking groove 19a for locking the first seal ring 29 is changed from the structure of the first example of the embodiment.

In this example, the radial depth dimensions of a pair of groove inner surfaces 12c and 12d constituting the inner surface of the outer ring locking groove 11a are made different from each other. In this example, when attaching the outer second seal ring 30 to the outer ring 2, the radial depth dimension of the axially inner groove inner surface 12d located on the front side with respect to the pushing direction of the outer second seal ring 30 is as follows: It is made larger than the radial depth dimension of the axially outer groove inner surface 12c located on the rear side with respect to the pushing direction of the outer second seal ring 30.

Further, in this example, the inner diameter of the groove inner surface 12c on the axially outer side of the outer ring locking groove 11a is made larger than the outer diameter of the outer second core bar 33 constituting the outer second seal ring 30, and the outer ring The inner diameter of the groove inner surface 12d on the axially inner side of the locking groove 11a is made smaller than the outer diameter of the outer second core metal 33 constituting the outer second seal ring 30.

Furthermore, the radial depth dimensions of the pair of groove inner surfaces 20c and 20d that constitute the inner surface of the hub wheel locking groove 19a are made different from each other. In this example, when attaching the first outer seal ring 29 to the hub ring 13, the radial depth dimension of the axially outer groove inner surface 20c located on the front side with respect to the pushing direction of the outer first seal ring 29 is determined. , is larger than the radial depth dimension of the axially inner groove inner surface 20d located on the rear side with respect to the pushing direction of the outer first seal ring 29.

Further, in this example, the outer diameter of the groove inner surface 20c on the axially outer side of the hub ring locking groove 19a is made larger than the inner diameter of the outer first core metal 31 constituting the outer first seal ring 29, and The outer diameter of the inner groove surface 20d on the axially inner side of the hub wheel locking groove 19a is made smaller than the inner diameter of the outer first core metal 31 constituting the outer first seal ring 29.

In this example as described above, the positioning of the first outer seal ring 29 and the second outer seal ring 30 can be performed without reducing the installation workability (insertion efficiency) of the first outer seal ring 29 and the second outer seal ring 30. can improve sexual performance.
Other configurations and effects are the same as in the first example of the embodiment.

As a modification of this example, as shown in FIG. 7, it is also possible to use a ring provided with a side lip 34c as the second outer seal ring 30a, similar to the structure of the second example of the embodiment. Even in the case of such a structure, the positioning efficiency of the first outer seal ring 29 and the second outer seal ring 30a is improved without reducing the workability of attaching the first outer seal ring 29 and the second outer seal ring 30a. can do.

[Sixth example of embodiment]
A sixth example of the embodiment will be described using FIGS. 8 and 9.

This example shows a case where the present invention is applied to an inner ring rotation type hub unit bearing for a drive wheel. The hub unit bearing 1a of this example includes an outer ring 2a, a hub 3a, a plurality of rolling elements 4a and 4b, an outer sealing member 5, and an inner sealing member 6a.

The outer ring 2a of this example has a tapered outer ring seal sliding surface 39 at the axially inner end of the inner peripheral surface. The outer ring seal sliding surface 39 is inclined by several degrees in a direction in which the inner diameter becomes larger toward the inner side in the axial direction. The outer ring 2a also has an outer ring locking groove 40 between the outer ring seal sliding surface 39 and the axially inner outer ring raceway 7b on the inner peripheral surface. The outer ring locking groove 40 is provided on the inner peripheral surface of the outer ring 2a over the entire circumference, and has a substantially rectangular cross-sectional shape. The radial depth dimensions of the pair of groove inner surfaces 41a and 41b that constitute the inner surface of the outer ring locking groove 40 are the same.

Since the hub unit bearing 1a of this example is for a driving wheel, the hub wheel 13a that constitutes the hub 3a is connected to a constant velocity joint. For this reason, the hub ring 13a has a spline hole 42 in the center thereof that penetrates in the axial direction. A drive shaft forming a constant velocity joint is engaged with the spline hole 42 through a spline. The inner ring 14a, which is externally fitted into the fitting cylinder part 22 provided on the axially inner side of the hub ring 13a, is held between the step surface 17 and the joint outer ring constituting the constant velocity joint from both sides in the axial direction. Ru. The drive shaft is rotationally driven directly by a drive source such as an engine or an electric motor, or is rotationally driven via a transmission. When the automobile is running, the hub 3a is rotationally driven by the drive shaft, thereby rotationally driving the wheels and the braking rotary body that are fixedly connected to the rotating flange 16 of the hub 3a.

The inner ring 14a has a cylindrical inner ring seal sliding contact surface 43 and an inner ring locking groove 44 on a portion (shoulder) of the outer peripheral surface that is axially inwardly removed from the inner ring raceway 15b on the axially inner side. The inner ring seal sliding surface 43 is provided at a portion of the outer circumferential surface of the inner ring 14a that radially faces the outer ring locking groove 40 on the axially inner side. The inner ring seal sliding surface 43 has a constant outer diameter in the axial direction. The inner ring locking groove 44 is provided in a portion of the outer circumferential surface of the inner ring 14a that radially faces the outer ring seal sliding surface 39 on the axially inner side. The inner ring locking groove 44 is provided all around the outer peripheral surface of the inner ring 14a, and has a substantially rectangular cross-sectional shape. A pair of groove inner surfaces 45a and 45b forming the inner surface of the inner ring locking groove 44 have the same radial depth dimension.

The hub unit bearing 1a of this example uses a combination seal ring consisting of two seal rings as the inner seal member 6a, similar to the outer seal member 5.

The inner sealing member 6a includes a circular first inner seal ring 46 disposed facing the external space 28 and a circular second inner seal ring 47 disposed facing the internal space 26. This is a combination seal ring. That is, the inner sealing member 6a is composed of two seal rings: a first inner seal ring 46 and a second inner seal ring 47 disposed adjacent to the axially outer side of the first inner seal ring 46. In this example, parts common to the outer sealing member 5 are used as the inner sealing member 6a. That is, the inner sealing member 6a has the same structure as the outer sealing member 5, and only the assembly direction with respect to the axial direction is opposite to that of the outer sealing member 5.

《Inner first seal ring》
The first inner seal ring 46 includes a first inner core bar 48 having a circular ring shape and a first inner elastic member 49 reinforced by the first inner core bar 48, and is supported on the outer peripheral surface of the inner ring 14a. There is. Therefore, the first inner seal ring 46 rotates together with the inner ring 14a. The inner first seal ring 46 has a sufficiently smaller axial width than its radial width. The first inner seal ring 46 is constructed by vulcanizing and bonding the first inner elastic material 49 to the first inner metal core 48 . Note that the inner first seal ring 46 has the same structure as the outer first seal ring 29, and only the assembly direction with respect to the axial direction is opposite to that of the outer first seal ring 29.

The inner first core bar 48 is made by pressing a metal plate such as a cold rolled steel plate. The inner first core metal 48 has a circular base plate portion 48a, an outer diameter cylindrical portion 48b, an inner diameter inclined portion 48c, and an inner diameter circular portion 48d.

The circular base plate portion 48a extends in the radial direction and has a circular ring shape. The annular base plate portion 48a is provided from the radially outer portion to the radially intermediate portion of the inner first core bar 48. The outer diameter side cylindrical portion 48b is provided at the radially outer end of the inner first core metal 48. The outer diameter side cylindrical portion 48b is bent from the radially outer end of the annular base portion 48a toward the axially outer side at a substantially right angle. The inner diameter side inclined portion 48c is provided on the radially inner side of the inner first core bar 48. The inner diameter side inclined portion 48c extends obliquely from the radially inner end of the annular base plate portion 48a in a direction toward the axially outer side as it goes radially inward. The inner circular ring portion 48d is provided at the radially inner end of the inner first core bar 48. The inner diameter side circular ring part 48d is arranged substantially parallel to the circular ring base plate part 48a, and is offset outward in the axial direction with respect to the circular ring base plate part 48a.

The inner first elastic member 49 is made of rubber (seal rubber) such as nitrile rubber, acrylic rubber, silicone rubber, fluororubber, ethylene propylene rubber, or hydrogenated nitrile rubber. The first inner elastic member 49 covers a portion of the surface of the first inner metal core 48 except for the outer surface in the axial direction of the annular base portion 48a. The first inner elastic member 49 has an annular inner elastic locking portion 49a at its inner peripheral edge, and a partially conical cylindrical outer lip 49b at its outer peripheral edge.

The inner circumferential elastic locking portion 49a is arranged radially inward than the inner circular ring portion 48d of the inner first core metal 48. A radially outer end of the inner elastic locking portion 49a is connected to a portion of the first inner elastic member 49 that covers the inner ring portion 48d. The inner peripheral elastic locking portion 49a has a substantially rectangular cross-sectional shape.

The outer circumferential lip 49b is disposed radially outward from the outer cylindrical portion 48b of the inner first core metal 48. The radially inner end of the outer lip 49b is connected to a portion of the first inner elastic member 49 that covers the outer circumferential surface of the outer cylindrical portion 48b. The outer circumferential lip 49b extends obliquely toward the axially inner side as it goes radially outward.

The first inner seal ring 46 locks an inner elastic locking portion 49a provided on the inner peripheral edge of the first inner elastic member 49 into an inner ring locking groove 44 provided on the outer peripheral surface of the inner ring 14a. Thus, it is supported by the inner ring 14a. In addition, while the first inner seal ring 46 is locked to the inner ring 14a, the outer lip 49b provided on the outer peripheral edge of the first inner elastic member 49 is connected to the tapered lip 49b provided on the inner peripheral surface of the outer ring 2a. It is brought into sliding contact with the outer ring seal sliding surface 39 over the entire circumference.

《Inner 2nd seal ring》
The second inner seal ring 47 includes a second inner metal core 50 having a ring shape and a second inner elastic member 51 reinforced by the second inner metal core 50, and is supported on the inner circumferential surface of the outer ring 2a. ing. Therefore, the inner second seal ring 47 does not rotate. The inner second seal ring 47 has a sufficiently smaller axial width than its radial width. The second inner seal ring 47 is constructed by vulcanizing and adhering the second inner elastic material 51 to the second inner metal core 50 . Note that the inner second seal ring 47 has the same structure as the outer second seal ring 30, and only the assembly direction with respect to the axial direction is opposite to that of the outer second seal ring 30.

The inner second core bar 50 is made by pressing a metal plate such as a cold rolled steel plate. The inner second core metal 50 has a circular base plate portion 50a, an outer diameter side inclined portion 50b, an outer diameter side circular ring portion 50c, and an inner diameter side inclined portion 50d.

The circular substrate portion 50a extends in the radial direction and has a circular ring shape. The circular base plate portion 50a is provided at a radially intermediate portion of the inner second core metal 50. The outer diameter side inclined portion 50b is provided on the radially outer side of the inner second core bar 50. The outer diameter side inclined portion 50b extends obliquely from the radially outer end of the annular base portion 50a toward the axially outer side as it goes radially outward. The outer diameter side circular ring portion 50c is provided at the radially outer end of the inner second core metal 50. The outer diameter side circular ring part 50c is arranged substantially parallel to the circular ring base plate part 50a, and is offset outward in the axial direction with respect to the circular ring base plate part 50a. The inner diameter side inclined portion 50d is provided at the radially inner end of the inner second core metal 50. The radially inner inclined portion 50d extends obliquely from the radially inner end of the annular base plate portion 50a toward the axially outer side as it goes radially inward.

The inner second elastic material 51 is made of rubber (seal rubber) such as nitrile rubber, acrylic rubber, silicone rubber, fluororubber, ethylene propylene rubber, or hydrogenated nitrile rubber. The inner second elastic material 51 covers a portion of the surface of the inner second core metal 50 except for the axially outer surface of the annular base portion 50a. The inner second elastic member 51 has an annular outer elastic locking portion 51a on the outer periphery, and has a partially conical cylindrical inner lip 51b on the inner periphery.

The outer circumferential elastic locking portion 51a is arranged radially outward from the outer circular ring portion 50c of the inner second core metal 50. A radially inner end portion of the outer circumferential elastic locking portion 51a is connected to a portion of the inner second elastic member 51 that covers the outer circumferential ring portion 50c. The outer peripheral elastic locking portion 51a has a substantially rectangular cross-sectional shape.

The inner circumferential lip 51b is arranged radially inward from the inner radially inclined portion 50d of the inner second core metal 50. The radially outer end of the inner lip 51b is connected to a portion of the second inner elastic member 51 that covers the inner radially inclined portion 50d. The inner circumferential lip 51b extends obliquely toward the axially inner side as it goes radially outward.

The inner second seal ring 47 has an outer circumferential elastic locking portion 51a provided on the outer peripheral edge of the inner second elastic member 51, and an outer ring locking groove provided on the inner circumferential surface of the outer ring 2a on the axially inner side. 40, it is supported by the outer ring 2a. In addition, while the second inner seal ring 47 is locked to the outer ring 2a, the inner lip 51b provided on the inner peripheral edge of the second inner elastic member 51 is connected to the cylindrical surface provided on the outer peripheral surface of the inner ring 14a. It is brought into sliding contact with the inner ring seal sliding surface 43 over the entire circumference. In this example, the inner opening of the internal space 26 in the axial direction is closed by such an inner sealing member 6a.

The inner sealing member 6a of this example is attached to the axially inner opening of the internal space 26 in the following manner.

That is, in this example, similarly to the assembly method of the first example of the embodiment, the process of inserting the hub ring 13a into the radially inner side of the outer ring 2a is performed, and the outer sealing member 5 is attached. Thereafter, the inner ring 14a is externally fitted into the fitting cylinder portion 22 provided on the axially inner side of the hub ring 13a, and then the inner sealing member 6a is inserted into the axially inner opening of the inner space 26 from the axially inner side. Push in the axial direction. Therefore, the inner sealing member 6a is installed between the outer ring 2a and the inner ring 14a after the outer sealing member 5a is attached.

Specifically, the inner second seal ring 47 is pushed axially into the outer ring 2a from the axially inner side while elastically deforming the outer circumferential elastic locking portion 51a provided on the outer circumferential edge. Then, the outer peripheral elastic locking portion 51a is locked in the outer ring locking groove 40 provided on the inner peripheral surface of the outer ring 2a. Thereby, the inner second seal ring 47 is supported against the inner circumferential surface of the outer ring 2a.

In this example, the inner circumferential lip 51b provided on the inner second seal ring 47 becomes axially inner, which corresponds to the rear side with respect to the pushing direction of the inner second seal ring 47, as it goes radially inward. Since it is inclined, the inner circumferential lip 51b will not be reversed during the installation work. However, in this example, since the second inner seal ring 47 uses a common part with the second outer seal ring 30 constituting the outer sealing member 5, the axially inner surface of the tip of the inner lip 51b It is provided with a tapered surface 51b1.

Thereafter, the first inner seal ring 46 is pushed axially into the inner ring 14a from the axially inner side while elastically deforming the inner elastic locking portion 49a provided on the inner circumferential edge. Then, the inner peripheral side elastic locking portion 49a is locked in the inner ring locking groove 44 provided on the outer peripheral surface of the inner ring 14a. This supports the inner first seal ring 46 against the outer peripheral surface of the inner ring 14a.

In the hub unit bearing 1a of the present example as described above, a combination seal ring consisting of a first inner seal ring 46 and a second inner seal ring 47, each of which has a circular ring shape, is used as the inner seal member 6a. Therefore, with respect to the hub unit bearing 1a for the driving wheels, it is possible to reduce the cost and to reduce the rotational torque.

Furthermore, in this example, the outer sealing member 5 and the inner sealing member 6a can use common parts, so that costs can be reduced.
Other configurations and effects are the same as in the first example of the embodiment.

As a first example of a modification of the present example, as shown in FIG. 10, a side lip 51c is used as the second inner seal ring 47a constituting the inner sealing member 6b, as in the structure of the second example of the embodiment. You can use what you have. Then, the tip of the side lip 51c can be brought into sliding contact over the entire circumference of the axially outer surface of the circular base plate portion 48a of the inner first metal core 48 constituting the inner first seal ring 46. If such a configuration is adopted, the sealing performance of the inner sealing member 6b can be improved.

Further, as a second example of a modification of the present example, like the structure of the third example of the embodiment, the outer second elastic member 34 constituting the outer sealing member 5 is made of conductive rubber, and the inner second elastic member 34 is made of conductive rubber. The inner second elastic member 51 constituting the second seal ring 47 can be made of conductive rubber. When such a configuration is adopted, it is possible to electrically conduct the outer ring 2a and the hub 3a by using elastic materials made of conductive rubber in each of the outer sealing member 5 and the inner sealing member 6a. Therefore, it becomes possible to parallelize the conductive circuits, and the conductivity can be improved.

Further, as a third example of a modification of the present example, as in the structure of the fourth example of the embodiment, there is a gap between the first outer seal ring 29 and the second outer seal ring 30 that constitute the outer sealing member 5b. , the conductive grease 38 can be filled, and the conductive grease can also be filled between the first inner seal ring 46 and the second inner seal ring 47 that constitute the inner sealing member 6a. In this case, conductive grease can be used in each of the outer sealing member 5b and the inner sealing member 6a to establish electrical continuity between the outer ring 2a and the hub 3a, thereby improving electrical conductivity.

Further, as a fourth example and a fifth example of a modification of the present example, as shown in FIGS. 11 and 12, the inner surface of the outer ring locking groove 40a is configured similarly to the structure of the fifth example of the embodiment. The radial depth dimensions of the pair of inner groove surfaces 41c and 41d can be made different from each other. Specifically, when attaching the second inner seal ring 47 to the outer ring 2a, the radial depth dimension of the axially outer groove inner surface 41c located on the front side with respect to the pushing direction of the inner second seal ring 47 is determined. can be made larger than the radial depth dimension of the axially inner groove inner surface 41d located on the rear side with respect to the pushing direction of the inner second seal ring 47.

Further, in this example, the inner diameter of the groove inner surface 41d on the axially inner side of the outer ring locking groove 40a is made larger than the outer diameter of the inner second core bar 50 constituting the inner second seal ring 47, and the outer ring The inner diameter of the groove inner surface 41c on the axially outer side of the locking groove 40a is made smaller than the outer diameter of the inner second core metal 50 that constitutes the inner second seal ring 47.

Further, the radial depth dimensions of the pair of groove inner surfaces 45c and 45d that constitute the inner surface of the inner ring locking groove 44a can be made different from each other. Specifically, when attaching the first inner seal ring 46 to the inner ring 14a, the radial depth dimension of the axially outer groove inner surface 45c located on the front side with respect to the pushing direction of the inner first seal ring 46 is determined. can be made larger than the radial depth dimension of the axially inner groove inner surface 45d located on the rear side with respect to the pushing direction of the inner first seal ring 46.

Further, in this example, the outer diameter of the groove inner surface 45c on the axially outer side of the inner ring locking groove 44a is made larger than the inner diameter of the inner first core metal 48 constituting the inner first seal ring 46, and the inner ring The outer diameter of the groove inner surface 45d on the axially inner side of the locking groove 44a is made smaller than the inner diameter of the inner first core bar 48 forming the inner first seal ring 46.

When such a configuration is adopted, the first inner seal ring 46 and the second inner seal ring 47 can be easily installed without reducing the installation workability (insertability) of the first inner seal ring 46 and the second inner seal ring 47. 47 can be improved.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be modified as appropriate without departing from the technical idea of the invention. In addition, the structures of the embodiments can be combined as appropriate as long as no contradiction occurs.

When carrying out the present invention, the structure of each part of the first outer seal ring and the second outer seal ring constituting the outer sealing member, as well as the structure of each part of the first outer seal ring and the second inner seal ring constituting the inner sealing member. The structure of each part is not limited to the structure shown in each example of the embodiment, and can be changed as appropriate.

1, 1a Hub unit bearing 2 Outer ring 3, 3a Hub 4a, 4b Rolling element 5, 5a, 5b Outer sealing member 6, 6a, 6b Inner sealing member 7a, 7b Outer ring raceway 8 Stationary flange 9 Support hole 10 Outer ring seal sliding surface 11, 11a Outer ring locking groove 12a-12d Groove inner surface 13, 13a Hub ring 14, 14a Inner ring 15a, 15b Inner ring raceway 16 Rotating flange 17 Step surface 18 Hub ring seal sliding contact surface 19, 19a Hub ring locking groove 20a~ 20d Groove inner surface 21 Pilot part 22 Fitting tube part 23 Caulking part 24 Mounting hole 25 Stud 26 Internal space 27a, 27b Retainer 28 External space 29 First outer seal ring 30, 30a Second outer seal ring 31 First outer core Gold 31a Circular substrate portion 31b Outer diameter cylindrical portion 31c Inner diameter side inclined portion 31d Inner diameter side circular portion 32 Outer first elastic member 32a Inner circumference elastic locking portion 32b Outer circumference lip 33 Outer second core bar 33a Circular ring Substrate part 33b Outer diameter side inclined part 33c Outer diameter side circular ring part 33d Inner diameter side inclined part 34 Outer second elastic member 34a Outer circumference side elastic locking part 34b Inner circumference side lip 34b1 Tapered surface 34c Side lip 35 Fitting cylinder part 36 Bottom plate part 36a Abutting part 37 Groove shoulder part 38 Conductive grease 39 Outer ring seal sliding surface 40, 40a Outer ring locking groove 41a to 41d Groove inner surface 42 Spline hole 43 Inner ring seal sliding surface 44, 44a Inner ring locking groove 45a ~45d Groove inner surface 46 Inner first seal ring 47, 47a Inner second seal ring 48 Inner first core metal 48a Circular base plate portion 48b Outer diameter side cylindrical portion 48c Inner diameter side inclined portion 48d Inner diameter side circular portion 49 Inner side first 1 Elastic material 49a Inner circumference side elastic locking part 49b Outer circumference side lip 50 Inner second core metal 50a Circular base plate part 50b Outer diameter side inclined part 50c Outer diameter side circular part 50d Inner diameter side inclined part 51 Inner second elastic member 51a Outer elastic locking portion 51b Inner lip 51c Side lip 100 Hub unit bearing 101 Outer ring 102 Inner ring 103 Balls 104 Outer sealing member 105 Inner sealing member 106 Outer raceway 107 Inner raceway 108 Retainer 109 Internal space 110 External space 111 Outside First seal ring 112 Second outer seal ring 113 First inner seal ring 114 Second inner seal ring

Claims (5)

The outer ring has a double-row outer ring raceway on the inner peripheral surface and does not rotate during use.
A hub that has a double-row inner raceway on its outer circumferential surface and rotates during use;
a plurality of rolling elements arranged in each row between the double-row outer ring raceway and the double-row inner ring raceway;
an outer sealing member that closes an axially outer opening of an internal space existing between the inner circumferential surface of the outer ring and the outer circumferential surface of the hub;
The hub includes a hub ring having an axially outer inner ring raceway of the double row inner ring raceway on an outer circumferential surface and a rotating flange at a portion located axially outer than the outer ring; an inner ring having an axially inner inner ring raceway of the inner ring raceways of the row on the outer peripheral surface;
The outer sealing member includes a first outer seal ring having a circular ring shape, which is disposed facing the external space, and supported by the hub ring, and a first outer seal ring, which is disposed facing the inner space, and has a circular ring shape, and which is disposed facing the inner space, and which is supported by the hub ring. and a second outer seal ring having an annular shape supported by a combination seal ring,
hub unit bearing. an inner sealing member that closes an axially inner opening of the internal space;
The inner sealing member includes a first inner seal ring having a circular ring shape and disposed facing the external space, and a second inner seal ring having a circular ring shape disposed facing the inner space. It is a combination seal ring,
The hub unit bearing according to claim 1. The hub unit bearing according to claim 1, wherein the second outer seal ring includes a conductive elastic material that electrically connects the outer ring and the hub. The hub unit bearing according to claim 1, wherein conductive grease is filled between the first outer seal ring and the second outer seal ring. A method for assembling a hub unit bearing according to any one of claims 1 to 4, comprising:
supporting the first outer seal ring between the rotating flange and the axially outer inner ring raceway on the outer peripheral surface of the hub ring;
supporting the outer second seal ring on a portion of the inner circumferential surface of the outer ring that is located axially outer than the axially outer outer ring raceway;
inserting the hub ring on which the first outer seal ring is supported into the radially inner side of the outer ring on which the second outer seal ring is supported;
How to assemble hub unit bearings.

Images