JP2025032928A - Wheel bearing device - Google Patents

Abstract

To provide a wheel bearing device which enables increase of the pole number of a magnetic encoder while maintaining the ability of a sensor to read the magnetic encoder.SOLUTION: An inner side sealing device 10 of a wheel bearing device 1 includes: a seal member 13 having a core grid 11 fixed to an outer ring 2 and an elastic member 12 joined to the core grid 11; a slinger 14 having an outer fitting part 141 fitted in an outer periphery of the inner ring 4 and an annular part 142 extending from the outer fitting part 141 to the outer diameter side; and a magnetic encoder 15 joined to the annular part 142 of the slinger 14. The annular part 142 faces an inner side end surface 2h of the outer ring 2 in an axial direction. An outer diameter end 151a of the magnetic encoder 15 is located at the outer diameter side relative to an opening part which is an inner periphery of the outer ring 2 and at the inner diameter side relative to an outer peripheral surface 2i of the outer ring 2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wheel bearing device.

Conventionally, wheel bearing devices that support the wheels rotatably in the suspension of vehicles such as automobiles, from light cars to large SUVs, are known. The wheel bearing device is provided with a sealing device that closes the open end of the annular space formed by the outer member and the inner member to prevent the intrusion of foreign matter such as muddy water. In this case, for example, a pack seal equipped with a magnetic encoder is used as the inner sealing device that closes the open end on the inner side of the annular space between the outer member and the inner member.

The magnetic encoder provided in the pack seal is constructed by mixing powder of a ferromagnetic material such as ferrite into rubber such as NBR and magnetizing it, as disclosed in Patent Document 1, for example. The magnetic encoder is magnetized so that the south and north poles are arranged alternately and at equal intervals in the direction of rotation.

When a pack seal equipped with such a magnetic encoder is used as an inner sealing device for a wheel bearing assembly, the maximum number of poles in the magnetic encoder is generally 48 south poles and 48 north poles, for a total of 96 poles.

For example, when a vehicle is driven autonomously, vehicle position information is calculated based on tire rotation information detected by a magnetic encoder, so increasing the number of poles in the magnetic encoder and shortening the vehicle's travel distance per pole is preferable for improving the accuracy of the calculated vehicle position information.

On the other hand, electric vehicles are increasingly being equipped with many batteries to extend driving distances, and are increasingly adopting dedicated platforms from the standpoint of battery arrangement, vehicle weight distribution, driving performance, energy regeneration during deceleration, and securing luggage space capacity. In addition, rear-wheel drive (RR) and four-wheel drive (4WD) are often used as drive systems for electric vehicles. Due to cost and maturity, wheel bearing devices similar to those traditionally used in internal combustion engine vehicles are often adopted for such electric vehicles.

Japanese Patent Application Publication No. 6-281018

However, the inner sealing device in the wheel bearing device is positioned between the outer member and the inner member, and the magnetic encoder provided in the inner sealing device is also located between the outer member and the inner member. Therefore, if the number of poles of the magnetic encoder is increased, the circumferential dimension per pole will become smaller, reducing the magnetic force of each pole, which may make it difficult for the sensor to read the magnetic encoder.

The present invention was made in consideration of the above situation, and provides a wheel bearing device that can increase the number of poles of the magnetic encoder while maintaining the magnetic encoder reading by the sensor by increasing the outer diameter of the magnetic encoder without changing the mounting space of the inner sealing device between the outer member and the inner member.

That is, the wheel bearing device is a wheel bearing device comprising an outer member having a double-row outer raceway surface on its inner circumference, an inner member having a double-row inner raceway surface on its outer circumference that faces the double-row outer raceway surface, double-row rolling elements accommodated in a rollable manner between the raceway surfaces of the outer member and the inner member, and a sealing device that closes an opening end on one axial side of an annular space formed by the outer member and the inner member, the sealing device being a core metal fixed to the outer member, The device is equipped with a seal member having an elastic member bonded to gold, a slinger having an outer fitting portion fitted to the outer periphery of the inner member and an annular portion extending from the outer fitting portion to the outer diameter side, and a magnetic encoder bonded to the annular portion of the slinger, the annular portion facing one axial end face of the outer member in the axial direction, and the outer diameter end of the magnetic encoder is located on the outer diameter side of the opening on one side, which is the inner circumference of the outer member, and on the inner diameter side of the outer diameter of the outer member.

According to the present invention, it is possible to increase the number of poles of a magnetic encoder while maintaining the ability of the sensor to read the magnetic encoder.

1 is a side cross-sectional view showing a wheel bearing device. 4 is a side cross-sectional view showing an inner sealing device fitted between an outer ring and an inner ring. FIG. FIG. 2 is a view of the magnetic encoder as seen from the axial direction. 10 is a side cross-sectional view showing an inner-side sealing device configured so that the axial position of an inner-side end face of a magnetic encoder is the same as the axial position of an inner-side end face of an inner ring. FIG. FIG. 6 is a side cross-sectional view showing a second embodiment of an outer ring and an inner sealing device. FIG. 11 is a side cross-sectional view showing a third embodiment of an outer ring and an inner sealing device. FIG. 11 is a side cross-sectional view showing a fourth embodiment of the outer ring. FIG. 4 is a side cross-sectional view showing a protective cover of the magnetic encoder. FIG. 11 is a side cross-sectional view showing a modified example of an inner sealing device when a protective cover is attached to an outer ring. 11 is a side cross-sectional view showing a second embodiment of a protective cover.

Below, the embodiment of the present invention will be explained with reference to the attached drawings.

[Wheel bearing device]
A wheel bearing device 1 shown in FIG. 1 is one embodiment of a wheel bearing device according to the present invention, which rotatably supports a wheel in a suspension system of a vehicle such as an automobile.

In the following description, the axial direction refers to the direction along the rotation axis X of the wheel bearing device 1. The inner side refers to one side in the axial direction, which is the side of the vehicle body of the wheel bearing device 1 when it is attached to the vehicle body, and the outer side refers to the other side in the axial direction, which is the side of the wheel of the wheel bearing device 1 when it is attached to the vehicle body.

The wheel bearing device 1 comprises an outer ring 2 as an outer member, a hub wheel 3 and an inner ring 4 as inner members, two rolling rows of inner ball rows 5 and outer ball rows 6, an outer seal member 9, an inner sealing device 10, and a constant velocity universal joint 20.

An inner side opening 2a is formed at the inner side end of the outer ring 2 into which the inner side sealing device 10 can be fitted. An outer side opening 2b is formed at the outer side end of the outer ring 2 into which the outer side seal member 9 can be fitted.

The inner side sealing device 10 is fitted into the inner side opening 2a to close the inner side opening end of the annular space S formed by the outer ring 2 and the inner member. The inner side sealing device 10 is an example of a sealing device that closes the opening end on one axial side of the annular space. The outer side seal member 9 is fitted into the outer side opening 2b to close the outer side opening end of the annular space S.

The inner peripheral surface of the outer ring 2 is formed with an inner outer raceway surface 2c and an outer outer raceway surface 2d. The outer peripheral surface of the outer ring 2 is integrally formed with a vehicle body mounting flange 2e for mounting the outer ring 2 to a knuckle 50, which is a vehicle body member. The vehicle body mounting flange 2e is provided with bolt holes 2f through which fastening members are inserted to fasten the vehicle body member and the outer ring 2.

The pilot portion 2g that fits into the knuckle 50 is located on the inner side of the vehicle body mounting flange 2e of the outer ring 2. The inner side opening 2a is formed by the inner peripheral surface of the pilot portion 2g.

The inner end of the outer circumferential surface of the hub wheel 3 is formed with a small diameter step 3a that is smaller in diameter than the outer end and extends in the axial direction. The outer end of the hub wheel 3 is integrally formed with a wheel mounting flange 3b for mounting a wheel.

The wheel mounting flange 3b has multiple bolt holes 3f. Hub bolts 3i are pressed into the bolt holes 3f to fasten the hub wheel 3 to the wheel or brake components.

The hub wheel 3 has an inner raceway surface 3c on the outer side that faces the outer raceway surface 2d on the outer side of the outer ring 2. The hub wheel 3 also has a lip sliding surface 3d on the base side of the wheel mounting flange 3b against which the outer seal member 9 slides.

A through hole 3e is formed in the inner diameter portion of the hub wheel 3 along the axial direction and is connected to the constant velocity universal joint 20. The through hole 3e passes through the hub wheel 3 in the axial direction.

The through hole 3e has a first hole 31 and a second hole 32. The second hole 32 is located on the outer side of the first hole 31. The inner diameter of the second hole 32 is larger than the inner diameter of the first hole 31, and a step surface 33 is formed between the first hole 31 and the second hole 32. The step surface 33 is a surface perpendicular to the rotation axis X, which is the axis of the first hole 31.

The inner ring 4 is provided on the small diameter step 3a of the hub wheel 3. The inner ring 4 is fixed to the small diameter step 3a of the hub wheel 3 by press fitting. The inner ring 4 has an inner side end face 4b at its inner side end.

The outer peripheral surface of the inner ring 4 is provided with an inner side inner raceway surface 4a that faces the outer raceway surface 2c on the inner side of the outer ring 2. In other words, the inner side of the inner member is formed by the inner ring 4, forming the inner raceway surface 4a.

The inner ball row 5 and outer ball row 6, which are rolling rows, are formed by a plurality of balls 7, which are rolling elements, held by a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway surface 4a of the inner ring 4 and the outer raceway surface 2c on the inner side of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer raceway surface 2d on the outer side of the outer ring 2.

In the wheel bearing device 1, a double row angular ball bearing is formed by the outer ring 2, the hub ring 3, the inner ring 4, the inner ball row 5, and the outer ball row 6. The wheel bearing device 1 may also be formed by a double row tapered roller bearing. In other words, the rolling elements accommodated between the raceway surfaces of the outer ring 2, the hub ring 3, and the inner ring 4 are not limited to balls 7, and may be rollers.

The constant velocity universal joint 20 is an inner member of the wheel bearing device 1 and has a shaft 21, a mouth portion 22, and a stem portion 23.

The shaft 21 is an axial member to which a driving force is input from a driving source such as an engine or a motor. The mouse section 22 supports the shaft 21 so that it can rotate about the rotation axis X. The shaft 21 is connected to the mouse section 22 so that torque can be transmitted.

The mouth portion 22 has an abutment portion 221 at its outer end that abuts against the inner end surface 4b of the inner ring 4. The outer end surface 221a of the abutment portion 221 abuts against the inner end surface 4b of the inner ring 4.

The stem portion 23 is formed integrally with the mouth portion 22 and extends from the abutment portion 221 of the mouth portion 22 toward the outer side in the axial direction. The stem portion 23 is spline-fitted with the first hole 31 in the through hole 3e of the hub wheel 3, so that the hub wheel 3 and the constant velocity universal joint 20 can rotate integrally.

A male threaded portion 23a is formed on the outer end of the stem portion 23, and a nut 41 is screwed onto the male threaded portion 23a, so that the hub wheel 3 and the constant velocity universal joint 20 are fastened together with the stem portion 23 fitted into the first hole 31 of the through hole 3e.

When the nut 41 is screwed onto the male threaded portion 23a of the stem portion 23, the abutment surface 221a of the abutment portion 221 in the mouth portion 22 abuts against the inner end surface 4b of the inner ring 4, and the nut 41 is engaged with the stepped surface 33 of the hub wheel 3. In this case, the stepped surface 33 that serves as the seat surface of the nut 41 is formed on a surface perpendicular to the axis of the first hole 31, so that the necessary axial force can be obtained when the nut 41 is screwed onto the male threaded portion 23a, and the fastened state between the hub wheel 3 and the constant velocity universal joint 20 can be stably maintained.

[Inner sealing device]
2, the inner sealing device 10 is fitted between the outer ring 2 and the inner ring 4. The inner sealing device 10 includes a seal member 13 having a core metal 11 fixed to the outer ring 2 and an elastic member 12 joined to the core metal 11, a slinger 14 fitted to the inner ring 4, and a magnetic encoder 15 joined to the slinger 14.

The core metal 11 is made of, for example, a steel plate, and is composed of a cylindrical inner fitting portion 111 that fits into the inner circumference of the inner side opening 2a of the outer ring 2, and an annular side plate portion 112 that extends from the outer side end of the inner fitting portion 111 toward the inner diameter side.

The elastic member 12 is made of, for example, synthetic rubber, and is integrally joined to the core metal 11 by vulcanization adhesion. The elastic member 12 has a base 121 that is vulcanization-adhered to the core metal 11, and a first side lip 122, a second side lip 123, and a grease lip 124 that extend from the base 121 and are each formed in an annular shape. The first side lip 122, the second side lip 123, and the grease lip 124 are seal lips that the elastic member 12 has.

The base 121 is joined to the inner peripheral surface, inner end face, and inner outer peripheral surface of the inner fitting portion 111, as well as to the inner side surface, which is one axial side surface of the side plate portion 112, the inner diameter side end face, and the inner diameter side portion of the outer side surface, which is the other axial side surface.

The first side lip 122 is located on the outermost side of the seal lips of the elastic member 12, and extends from the base 121 toward the outer diameter side and the inner side. The second side lip 123 is located on the inner diameter side of the first side lip 122, and extends from the base 121 toward the outer diameter side and the inner side. The grease lip 124 is located on the inner diameter side of the second side lip 123, and extends from the base 121 toward the inner diameter side and the outer side.

The slinger 14 is made of, for example, a steel plate, and has a cylindrical outer fitting portion 141 that fits onto the outer peripheral surface at the inner end of the inner ring 4, and an annular portion 142 that extends from the inner end of the outer fitting portion 141 to the outer diameter side.

The annular portion 142 of the slinger 14 is located axially inward of the side plate portion 112 of the core metal 11. The annular portion 142 has an inner diameter portion 142a that faces the side plate portion 112 of the core metal 11 in the axial direction, an outer diameter portion 142b that is located on the outer diameter side of the inner diameter portion 142a, and a step portion 142c that connects the inner diameter portion 142a and the outer diameter portion 142b.

The outer diameter portion 142b extends radially outward beyond the inner circumferential surface that forms the inner side opening 2a of the outer ring 2, and faces the inner side end face 2h of the pilot portion 2g of the outer ring 2 in the axial direction. The outer diameter portion 142b is located on the inner side of the inner diameter portion 142a in the axial direction. The inner diameter portion 142a and the outer diameter portion 142b extend radially perpendicular to the axial direction, and the step portion 142c is inclined relative to the radial direction.

In the slinger 14, the outer diameter portion 142b is located on the inner side of the inner diameter portion 142a, and the outer diameter portion 142b and the inner diameter portion 142a are connected by a step portion 142c, but it is also possible to position the outer diameter portion 142b and the inner diameter portion 142a in the same axial position and directly connect the outer diameter portion 142b and the inner diameter portion 142a.

The first side lip 122 of the elastic member 12 faces the inner diameter portion 142a of the annular portion 142 of the slinger 14 in the axial direction, and the tip of the first side lip 122 is in slidable contact with the inner diameter portion 142a. In other words, the first side lip 122 is a contact lip.

The lip portion 122a is the portion of the first side lip 122 that is closest to the inner diameter portion 142a and that is in contact with the inner diameter portion 142a. The lip portion 122a is located on the innermost side of the first side lip 122.

The second side lip 123 of the elastic member 12 faces the inner diameter portion 142a of the annular portion 142 of the slinger 14 in the axial direction, and the tip of the second side lip 123 is in sliding contact with the inner diameter portion 142a. In other words, the second side lip 123 is a contact lip.

The portion of the second side lip 123 that is closest to the inner diameter portion 142a and that comes into contact with the inner diameter portion 142a is the lip portion 123a. The lip portion 123a is located on the innermost side of the second side lip 123.

The grease lip 124 of the elastic member 12 faces the outer fitting portion 141 of the slinger 14 in the radial direction, and the tip of the grease lip 124 is in slidable contact with the outer fitting portion 141. In other words, the grease lip 124 is a contact lip.

The first side lip 122 and the second side lip 123 are seal lips that extend from the base 121 of the elastic member 12 toward the annular portion 142 of the slinger 14 in the axial direction. The grease lip 124 is a seal lip that extends from the base 121 of the elastic member 12 toward the outer fitting portion 141 of the slinger 14 in the radial direction.

The magnetic encoder 15 is bonded to the inner side of the annular portion 142 of the slinger 14. The magnetic encoder 15 is formed from synthetic rubber mixed with magnetic powder such as ferrite, and is bonded integrally to the annular portion 142 of the slinger 14 by vulcanization adhesion. The magnetic encoder 15 is bonded to the slinger 14 by, for example, insert molding together with the slinger 14.

The magnetic encoder 15 has a magnetized portion 151 and a non-magnetized portion 152 that is not magnetized and is located on the inner diameter side of the magnetized portion 151. The magnetized portion 151 has a thickness in the axial direction that is greater than that of the non-magnetized portion 152.

In this embodiment, the magnetized portion 151 is joined to the outer diameter portion 142b and the step portion 142c of the annular portion 142, and the non-magnetized portion 152 is joined to the inner diameter portion 142a of the annular portion 142.

However, the magnetized portion 151 only needs to be formed on at least the outer diameter portion 142b. In addition, the inner diameter side end portion 152a of the non-magnetized portion 152 is in contact with the outer peripheral surface of the inner ring 4, preventing foreign matter such as muddy water from penetrating into the annular space S between the outer peripheral surface of the inner ring 4 and the outer fitting portion 141 of the slinger 14.

As shown in FIG. 3, in the magnetized portion 151, N magnetic poles and S magnetic poles are magnetized alternately at equal pitch in the circumferential direction. In this embodiment, 60 N magnetic poles and 60 S magnetic poles are formed in the magnetized portion 151. In other words, 60 pairs of N magnetic poles and S magnetic poles are formed.

In the magnetized portion 151, the number of pairs of magnetic poles N and S can be 49 pole pairs or more and 70 pole pairs or less. If the number of pairs of magnetic poles N and S is 49 pole pairs, the total number of poles of magnetic poles N and S is 98 poles, and if the number of pairs of magnetic poles N and S is 70 pole pairs, the total number of poles of magnetic poles N and S is 140 poles.

As shown in Figures 1 and 2, a rotational speed sensor 51 that protrudes from the knuckle 50 toward the inner diameter side is attached to the knuckle 50 into which the outer peripheral surface 2i of the pilot portion 2g is fitted. The rotational speed sensor 51 is an example of a sensor. The rotational speed sensor 51 faces the magnetized portion 151 of the magnetic encoder 15 in the axial direction. The rotational speed sensor 51 detects changes in the magnetic flux density of the magnetized portion 151 in the magnetic encoder 15, making it possible to detect the rotational speed of the inner ring 4.

A labyrinth LB1 is formed between the knuckle 50 in which the pilot portion 2g is fitted and the outer diameter end 151a of the magnetized portion 151 of the magnetic encoder 15. The labyrinth LB1 prevents foreign matter such as muddy water from entering the inside of the inner sealing device 10 from the outside.

The inner sealing device 10 is fitted between the inner opening 2a of the outer ring 2 and the outer peripheral surface of the inner ring 4, and the radial length between the inner opening 2a of the outer ring 2 and the outer peripheral surface of the inner ring 4 can be set to, for example, 6 mm to 10 mm.

[Magnetic Encoder Position]
As shown in FIG. 2 , an outer ring pilot outer diameter, which is the radial length from the rotation axis X to the outer peripheral surface 2i of the pilot portion 2g of the outer ring 2, is Ra, a magnetic encoder outer diameter, which is the radial length from the rotation axis X to the outer diameter side end 151a of the magnetized portion 151 in the magnetic encoder 15, is Rb, and an outer ring pilot inner diameter, which is the radial length from the rotation axis X to the inner side opening 2a of the pilot portion 2g of the outer ring 2, is Rc.

The outer race pilot outer diameter Ra, the magnetic encoder outer diameter Rb, and the outer race pilot inner diameter Rc have a relationship of Rc<Rb<Ra. In other words, the outer diameter end 151a of the magnetized portion 151, which is the outer diameter end of the magnetic encoder 15, is located on the outer diameter side of the inner side opening 2a of the pilot portion 2g, which is the inner circumference of the outer race 2, and is located on the inner diameter side of the outer peripheral surface 2i of the pilot portion 2g, which is the outer diameter of the outer race 2. The inner side opening 2a is an example of an opening on one side, which is the inner circumference of the outer member. The inner diameter side end 151b of the magnetized portion 151 is located on the inner diameter side of the lip portion 122a of the first side lip 122, which is the seal lip located on the outermost diameter side.

In this way, because the magnetic encoder outer diameter Rb is formed larger than the outer ring pilot inner diameter Rc, it is possible to increase the circumferential length of the magnetized portion 151 compared to when the magnetic encoder 15 is disposed only between the inner side opening 2a of the pilot portion 2g and the outer peripheral surface of the inner ring 4.

By increasing the circumferential length of the magnetized portion 151, the number of magnetic poles (N poles and S poles) in the magnetized portion 151 can be increased, and by increasing the number of poles in the magnetic encoder 15, the vehicle's travel distance per pole can be shortened, thereby improving the accuracy of the calculated vehicle position information.

In addition, even if the number of poles, N poles and S poles, in the magnetized portion 151 is increased, the circumferential dimensions per pole of the N pole and the S pole can be prevented from becoming excessively small, and it is possible to maintain the reading of the magnetic encoder 15 by the rotation speed sensor 51. In other words, it is possible to increase the number of poles of the magnetic encoder 15 while maintaining the reading of the magnetic encoder 15 by the rotation speed sensor 51.

The outermost lip diameter, which is the radial length from the rotation axis X to the lip portion 122a of the first side lip 122, is Rd, and the sensing diameter, which is the radial length from the rotation axis X to the reading position 151c of the rotation speed sensor 51 of the magnetized portion 151, is Re.

The outermost lip diameter Rd and the sensing diameter Re have a relationship of Rd < Re. In other words, the reading position 151c by the rotational speed sensor 51 of the magnetic encoder 15 is located on the outer diameter side of the lip portion 122a of the first side lip 122, which is the seal lip located on the outermost diameter side.

In this way, since the sensing diameter Re is formed larger than the lip outermost diameter Rd, the circumferential length of the magnetized portion 151 at the reading position 151c can be increased, and even if the number of magnetic poles N and S is increased, it is possible to maintain the reading of the magnetic encoder 15 by the rotation speed sensor 51.

The outer ring pilot inner diameter Rc, the lip outermost diameter Rd, and the sensing diameter Re have a relationship of Rd<Rc<Re. In other words, the inner side opening 2a of the pilot portion 2g, which is the inner circumference of the outer ring 2, is located on the inner diameter side of the reading position 151c of the magnetic encoder 15, and is located on the outer diameter side of the lip portion 122a of the first side lip 122. The reading position 151c of the magnetic encoder 15 is also located on the outer diameter side of the inner side opening 2a.

As a result, the reading position 151c of the magnetic encoder 15 is located on the outer diameter side of the inner side opening 2a of the outer ring 2, and even if the circumferential length at the reading position 151c is increased and the number of magnetic poles N and S is increased, it is possible to maintain reading of the magnetic encoder 15 by the rotation speed sensor 51.

In addition, in the wheel bearing device 1 shown in FIG. 2, the inner end face of the magnetized portion 151 in the magnetic encoder 15 is located slightly more inward than the inner end face 4b of the inner ring 4, but as shown in FIG. 4, it is also possible to configure the axial position of the inner end face of the magnetized portion 151 in the magnetic encoder 15 and the axial position of the inner end face 4b of the inner ring 4 to be in the same position.

In other words, the inner end surface of the magnetized portion 151 of the magnetic encoder 15 and the inner end surface 4b of the inner ring 4 can be configured to be on the same plane in a plane perpendicular to the axial direction. By configuring it in this way, the magnetized portion 151 of the magnetic encoder 15 does not protrude further to the inner side than the inner ring 4, and the wheel bearing device 1 can be prevented from becoming larger in the axial direction.

The inner end face of the magnetized portion 151 in the magnetic encoder 15 and the inner end face 4b of the inner ring 4 are not necessarily on the same plane. However, by configuring the difference between the axial position of the inner end face of the magnetized portion 151 and the axial position of the inner end face 4b of the inner ring 4 to be within ±1 mm, it is possible to prevent the wheel bearing device 1 from becoming large in the axial direction.

In addition, in the wheel bearing device 1, the magnetic encoder 15 is joined to the slinger 14 of the inner sealing device 10 and is formed integrally with the inner sealing device 10, making it possible to reduce the number of parts in the wheel bearing device 1 compared to when the magnetic encoder 15 and the inner sealing device 10 are formed separately.

[Second embodiment of outer ring and inner sealing device]
The outer ring 2 and the inner sealing device 10 may also be configured as an outer ring 2A and an inner sealing device 10A shown in FIG.

The outer ring 2A differs from the outer ring 2 in that the inner end of the pilot portion 2g is cut out on the outer diameter side. The inner end of the pilot portion 2g of the outer ring 2A has a cutout outer peripheral surface 2j that is located on the inner diameter side of the outer peripheral surface 2i.

The outer peripheral surface 2j of the cutout portion is located on the inner side of the outer peripheral surface 2i in the axial direction, and the outer peripheral surface 2j of the cutout portion and the outer peripheral surface 2i are connected by a connection surface 2k. In the outer ring 2A, the connection surface 2k is formed as an inclined surface that slopes toward the inner diameter side as it approaches the inner side.

The inner sealing device 10A differs from the inner sealing device 10 in that it has a slinger 14A instead of the slinger 14. The slinger 14A has a reinforcing portion 143 in addition to an outer fitting portion 141 and an annular portion 142.

The reinforcing portion 143 is a cylindrical portion that extends from the outer diameter end of the outer diameter portion 142b of the annular portion 142 toward the outer side. When viewed from the radial direction, the reinforcing portion 143 faces the outer peripheral surface 2j of the notch portion of the pilot portion 2g of the outer ring 2A. In other words, when viewed from the radial direction, the reinforcing portion 143 overlaps with the outer ring 2A. In the radial direction, the reinforcing portion 143 is located between the outer peripheral surface 2i of the outer ring 2A and the outer peripheral surface 2j of the notch portion.

The reinforcing portion 143 can be formed, for example, by bending the outer diameter end of the outer diameter portion 142b toward the outer side. In this way, the slinger 14A has the reinforcing portion 143 that extends toward the outer side at the outer diameter end of the annular portion 142 and overlaps with the outer ring 2A when viewed from the radial direction.

In the slinger 14A, the outer diameter portion 142b of the annular portion 142 extends outward beyond the inner opening 2a of the outer ring 2A, making the annular portion 142 larger in diameter. However, since the slinger 14A has the reinforcing portion 143, the rigidity of the slinger 14A is increased, making it possible to prevent deformation of the slinger 14A.

A labyrinth LB2 is formed between the knuckle 50 to which the pilot portion 2g is fitted and the reinforcing portion 143 of the slinger 14A, and the labyrinth LB2 prevents foreign matter such as muddy water from entering the inside of the inner sealing device 10 from the outside.

[Third embodiment of outer ring and inner sealing device]
The outer ring 2 and the inner sealing device 10 may also be configured as an outer ring 2B and an inner sealing device 10B shown in FIG.

The outer ring 2B differs from the outer ring 2 in that the inner end of the pilot portion 2g is cut out on the outer diameter side. The inner end of the pilot portion 2g in the outer ring 2B has a cutout outer peripheral surface 2j that is located on the inner diameter side of the outer peripheral surface 2i.

The cutout outer peripheral surface 2j is located on the inner side of the outer peripheral surface 2i in the axial direction, and the cutout outer peripheral surface 2j and the outer peripheral surface 2i are connected by a connection surface 2k. In the outer ring 2B, the connection surface 2k faces the inner side in the axial direction and is formed as a surface that extends in a direction perpendicular to the axial direction.

The inner sealing device 10B differs from the inner sealing device 10 in that it is equipped with a slinger 14B and a magnetic encoder 15B instead of the slinger 14 and the magnetic encoder 15.

The slinger 14B has an outer peripheral portion 144 in addition to the outer fitting portion 141 and the annular portion 142. The outer peripheral portion 144 is a cylindrical portion that extends from the outer diameter end of the outer diameter portion 142b of the annular portion 142 toward the outer side.

The outer peripheral portion 144 faces the outer peripheral surface 2j of the notch portion of the pilot portion 2g in the outer ring 2B when viewed from the radial direction. In other words, the outer peripheral portion 144 overlaps with the outer ring 2B when viewed from the radial direction. The outer peripheral portion 144 is located between the outer peripheral surface 2i of the outer ring 2B and the outer peripheral surface 2j of the notch portion in the radial direction.

The outer peripheral portion 144 of the slinger 14B extends further outward than the reinforcing portion 143 of the slinger 14A, and the axial length of the outer peripheral portion 144 is greater than the axial length of the reinforcing portion 143.

The magnetic encoder 15B has a magnetized portion 151 and a non-magnetized portion 152. The magnetized portion 151 is joined to the outer peripheral surface of the outer peripheral portion 144 of the slinger 14B. The non-magnetized portion 152 is joined to the inner diameter portion 142a, the outer diameter portion 142b, and the inner side surface of the stepped portion 142c of the annular portion 142.

When the magnetized portion 151 of the magnetic encoder 15B is joined to the outer peripheral surface of the outer peripheral portion 144 of the slinger 14B, as in the inner sealing device 10B, it is possible to read the magnetized portion 151 by placing the rotational speed sensor 51 on the outer diameter side of the outer peripheral portion 144.

In this case, since the outer peripheral portion 144 of the slinger 14B is located on the outer diameter side of the inner side opening 2a of the pilot portion 2g, which is the inner circumference of the outer ring 2B, it is possible to increase the circumferential length of the magnetized portion 151. As a result, even if the number of magnetic poles N and S in the magnetized portion 151 is increased, the circumferential dimension per pole of the magnetic poles N and S can be prevented from becoming excessively small, and it is possible to maintain the reading of the magnetic encoder 15B by the rotation speed sensor 51.

A labyrinth LB3 is formed between the knuckle 50, to which the pilot portion 2g is fitted, and the magnetized portion 151 of the magnetic encoder 15B. The labyrinth LB3 prevents foreign matter such as muddy water from entering the inside of the inner sealing device 10 from the outside.

[Fourth embodiment of outer ring]
The outer ring 2 can also be configured as an outer ring 2C shown in Fig. 7. The outer ring 2C differs from the outer ring 2 in that it has a covering portion 2m that protrudes toward the inner side from the outer diameter side end portion of the inner side end face 2h of the pilot portion 2g.

The covering portion 2m is located on the outer diameter side of the outer diameter end of the magnetized portion 151 of the magnetic encoder 15, and overlaps with the magnetized portion 151 of the magnetic encoder 15 when viewed from the radial direction. In other words, the covering portion 2m covers the outer diameter side of the magnetic encoder 15.

When the pilot portion 2g of the outer ring 2, which does not have a coating portion 2m, is fitted into the knuckle 50, the outer peripheral surface 2i of the pilot portion 2g and the outer diameter end of the magnetic encoder 15 are located close to each other, so there is a risk that the magnetic encoder 15 will come into contact with the knuckle 50 and cause deformation of the magnetic encoder 15.

However, as in the outer ring 2C, the pilot portion 2g has a coating portion 2m that covers the outer diameter side of the magnetic encoder 15, so that when the pilot portion 2g of the outer ring 2 is fitted into the knuckle 50, the magnetic encoder 15 is protected by the coating portion 2m and does not come into contact with the knuckle 50, thereby preventing deformation of the magnetic encoder 15.

A labyrinth LB4 is formed between the knuckle 50, to which the pilot portion 2g is fitted, and the covering portion 2m, and the labyrinth LB4 prevents foreign matter such as muddy water from entering the inside of the inner sealing device 10 from the outside.

[Magnetic encoder protective cover]
8, a protective cover 60 for protecting the magnetic encoder 15 can be attached to the pilot portion 2g of the outer ring 2 into which the inner-side sealing device 10 is fitted. The protective cover 60 has a fitting portion 61 that is fitted into the outer peripheral surface 2i of the pilot portion 2g, and a protective plate portion 62 that extends from the inner end portion of the fitting portion 61 to the inner diameter side.

The fitting portion 61 protrudes further inward than the inner end face 2h in the axial direction, and covers the outer diameter side of the magnetic encoder 15. The protective plate portion 62 is located on the inner side of the magnetic encoder 15, and covers the inner side of the magnetic encoder 15. The protective plate portion 62 and the magnetic encoder 15 face each other with a gap in the axial direction. The protective plate portion 62 is located between the magnetic encoder 15 and the rotational speed sensor 51 arranged opposite the magnetic encoder 15.

The protective cover 60 is made of a non-magnetic material such as SUS, and even if the protective plate portion 62 is interposed between the magnetic encoder 15 and the rotation speed sensor 51, it does not affect the reading of the magnetic encoder 15 by the rotation speed sensor 51. The pilot portion 2g of the outer ring 2 is fitted into the knuckle 50 via the fitting portion 61 of the protective cover 60.

By attaching a protective cover 60 that covers the outer diameter side and inner side of the magnetic encoder 15 to the pilot portion 2g of the outer ring 2, when the pilot portion 2g of the outer ring 2 is fitted into the knuckle 50, the magnetic encoder 15 is protected by the protective cover 60 and does not come into contact with the knuckle 50, thereby preventing deformation of the magnetic encoder 15.

The gap between the magnetized portion 151 of the magnetic encoder 15 and the protective plate portion 62 of the protective cover 60 is set to a size of approximately 0.1 mm to 0.8 mm. This forms a labyrinth LB5 between the magnetic encoder 15 and the protective cover 60, which prevents foreign matter such as muddy water from entering the inside of the inner sealing device 10 from the outside.

In addition, when the wheel bearing device 1 is attached to the vehicle body, a drain hole can be formed in the portion of the protective cover 60 that faces the road surface to drain muddy water that has entered the protective cover 60. The drain hole can be formed, for example, in the lower end of the portion of the protective cover 60 that protrudes further toward the inner side than the inner end surface 2h in the fitting portion 61.

(Modification of the inner sealing device when a protective cover is attached)
9, when a protective cover 60 is attached to the pilot portion 2g of the outer ring 2, the inner-side sealing device 10 can be configured as an inner-side sealing device 10C. The inner-side sealing device 10C differs from the inner-side sealing device 10 in that it has an elastic member 12C instead of the elastic member 12.

The elastic member 12C does not have a first side lip 122 as a seal lip, but only has a second side lip 123 and a grease lip 124. In other words, while the elastic member 12 of the inner sealing device 10 has three seal lips, the elastic member 12C of the inner sealing device 10C has two seal lips.

Furthermore, while the elastic member 12 of the inner sealing device 10 has a first side lip 122 and a second side lip 123 as seal lips extending from the core metal 11 toward the annular portion 142 of the slinger 14, the elastic member 12C of the inner sealing device 10C has only one second side lip 123 as a seal lip extending from the core metal 11 toward the annular portion 142 of the slinger 14.

When the protective cover 60 is attached to the pilot portion 2g of the outer ring 2, a labyrinth LB5 is formed between the magnetic encoder 15 and the protective cover 60, improving the muddy water resistance. Therefore, even if the number of seal lips is reduced, as in the elastic member 12C of the inner sealing device 10C, the muddy water resistance of the wheel bearing device 1 can be maintained overall. In addition, by reducing the number of seal lips, as in the elastic member 12C of the inner sealing device 10C, it is possible to reduce the rotational torque of the wheel bearing device 1.

Even if the protective cover 60 is not attached to the pilot portion 2g of the outer ring 2 as shown in FIG. 2, a labyrinth LB1 is formed between the knuckle 50 and the outer diameter side end 151a of the magnetic encoder 15, improving muddy water resistance. Therefore, by using the inner sealing device 10C instead of the inner sealing device 10, it is possible to reduce the rotational torque of the wheel bearing device 1 while maintaining muddy water resistance.

[Second embodiment of protective cover for magnetic encoder]
The protective cover 60 may be configured as a protective cover 60A shown in Fig. 10. The protective cover 60A has a flange portion 63 in addition to a fitting portion 61 and a protective plate portion 62.

The flange 63 extends from the inner diameter end of the protective plate 62 toward the inner side, and faces the outer circumferential surface 221b of the abutment portion 221 of the constant velocity universal joint 20 with a gap in the radial direction. The flange 63 can be formed, for example, by bending the inner diameter end of the protective plate 62 toward the inner side.

A labyrinth LB6 is formed between the outer peripheral surface 221b of the abutment portion 221 of the constant velocity universal joint 20 and the flange portion 63 of the protective cover 60A. By forming the labyrinth LB6 between the outer peripheral surface 221b of the abutment portion 221 and the flange portion 63, the labyrinth LB6 can prevent foreign matter such as muddy water from entering between the magnetic encoder 15 and the protective plate portion 62 of the protective cover 60A from the outside. This can further prevent foreign matter such as muddy water from entering the inside of the inner sealing device 10.

In this embodiment, the wheel bearing device 1 is configured as a wheel bearing device 1 of a third generation structure in which the inner raceway surface 3c is formed directly on the outer periphery of the hub wheel 3, but this is not limited to this, and it may be a second generation structure in which a pair of inner rings 4 are press-fitted and fixed to the hub wheel 3. Also, the wheel bearing device 1 can be configured as a fourth generation structure in which, instead of forming an inner raceway surface facing the outer raceway surface 2c of the outer ring 2 on the inner ring 4, it is formed as a constant velocity universal joint as an inner member that fits into the through hole 3i of the hub wheel 3, and does not have an inner ring 4.

Although the embodiments of the present invention have been described above, the present invention is in no way limited to these embodiments, which are merely examples, and it goes without saying that the present invention can be embodied in various other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims.

LIST OF SYMBOLS 1 Wheel bearing device 2, 2A, 2B, 2C Outer ring 2a Inner opening 2c (inner) outer raceway surface 2d (outer) outer raceway surface 2g Pilot portion 2h Inner end face 2i Outer peripheral surface 2m Covering portion 3 Hub ring 3a Small diameter step portion 3c Inner raceway surface 3e Through hole 4 Inner ring 4a Inner raceway surface 4b Inner end face 5 Inner ball row 6 Outer ball row 7 Ball 8 Cage 10, 10A, 10B, 10C Inner sealing device 11 Core 12, 12C Elastic member 13 Seal member 14, 14A, 14B Slinger 15, 15B Magnetic encoder 20 Constant velocity universal joint 23 Stem portion 60, 60A Protective cover 61 Fitting portion 62 Protective plate portion 63 Flange portion 111 Internal fitting portion 112 Side plate portion 122 First side lip 122a Lip portion 123 Second side lip 123a Lip portion 124 Grease lip 141 External fitting portion 142 Annular portion 143 Reinforcement portion 144 Outer periphery 151 Magnetized portion 151c Reading position 152 Non-magnetized portion 221 Contact portion 221b Outer periphery

Claims (11)

an outer member having a double row outer raceway surface on an inner periphery thereof;
an inner member having a double row inner raceway surface on an outer periphery thereof facing the double row outer raceway surface;
a double row of rolling elements rollably accommodated between the raceway surfaces of the outer member and the inner member;
a sealing device that closes an open end on one axial side of an annular space formed by the outer member and the inner member,
The sealing device includes:
a seal member having a core metal fixed to the outer member and an elastic member joined to the core metal;
a slinger having an outer fitting portion that is fitted onto an outer periphery of the inner member and an annular portion that extends radially outward from the outer fitting portion;
a magnetic encoder joined to the annular portion of the slinger,
the annular portion faces one axial end surface of the outer member in the axial direction,
The wheel bearing device has an outer diameter end of the magnetic encoder located on the outer diameter side of an opening on one side which is the inner circumference of the outer member and on the inner diameter side of the outer diameter of the outer member. the elastic member has a seal lip extending from the core metal toward the annular portion,
The seal lip has a lip portion located closest to the annular portion in the axial direction,
2. The wheel bearing device according to claim 1, wherein a reading position by the sensor of the magnetic encoder is located on the outer diameter side of the lip portion of the seal lip that is located on the outermost diameter side. The wheel bearing device according to claim 2, wherein the reading position is located on the outer diameter side of the opening on one side, which is the inner circumference of the outer member. The wheel bearing device according to claim 2 or 3, wherein the elastic member has a single seal lip extending from the core metal toward the annular portion. The wheel bearing device according to any one of claims 1 to 3, wherein the slinger has a reinforcing portion that extends from the outer diameter end of the annular portion to the other axial direction and overlaps with the outer ring when viewed from the radial direction. the slinger has an outer circumferential portion that extends from an outer diameter side end of the annular portion toward the other side in the axial direction and overlaps with the outer ring when viewed in the radial direction,
The wheel bearing device according to any one of claims 1 to 3, wherein the magnetic encoder is joined to an outer circumferential surface of the outer circumferential portion of the slinger. The wheel bearing device according to any one of claims 1 to 3, wherein the outer ring has a covering portion that extends axially further than the axial end face on the outer diameter side of the outer diameter end of the magnetic encoder and overlaps with the magnetic encoder when viewed from the radial direction. The wheel bearing device according to any one of claims 1 to 3, further comprising a protective cover having a fitting portion that fits onto the outer periphery of the outer ring, and a protective plate portion that extends from the outer fitting portion to the inner diameter side on one axial side of the magnetic encoder and covers the magnetic encoder. The wheel bearing device according to claim 8, wherein the gap in the axial direction between the magnetic encoder and the protective plate is 0.1 mm to 0.8 mm. The hub wheel has a through hole passing therethrough in an axial direction,
a constant velocity universal joint having a stem portion that can be fitted into the through hole of the hub wheel and an abutment portion that abuts against the inner member from one axial side,
9. The wheel bearing device according to claim 8, wherein the protective cover has a flange portion that extends from an inner diameter side end portion of the protective plate portion to one side in the axial direction and faces an outer circumferential surface of the abutment portion with a gap therebetween. The wheel bearing device according to any one of claims 1 to 3, wherein the axial end face of the magnetic encoder and the axial end face of the inner ring are flush with each other in a plane perpendicular to the axial direction.

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