JP6788453B2 - Bearing device for wheels - Google Patents

Description

The present invention relates to a wheel bearing device.

Conventionally, a wheel bearing device that rotatably supports a wheel in a suspension device such as an automobile has been known. In the wheel bearing device, an outer member is fixed to a knuckle constituting the suspension device. Further, in the wheel bearing device, an inner member is arranged inside the outer member, and a rolling element is interposed between the outer member and the inner member. In this way, the wheel bearing device constitutes a rolling bearing structure and makes the wheels attached to the inner members rotatable.

By the way, in such a wheel bearing device, when muddy water or the like enters the annular space formed between the outer member and the inner member, the rolling element and its rolling surface are damaged and the bearing life is shortened. Further, even if the grease sealed in the annular space leaks, the rolling element and its rolling surface are damaged and the bearing life is shortened. Therefore, the wheel bearing device is provided with a sealing member that seals the annular space in order to prevent the intrusion of muddy water and the like and the leakage of grease. For example, as described in Patent Document 1 and Patent Document 2.

The wheel bearing device described in Patent Document 1 includes an outer member, an inner member, a rolling element interposed between the outer member and the inner member, and between the outer member and the inner member. It includes a sealing member that seals the formed annular space. However, in such a wheel bearing device, when muddy water travels through the outer member and reaches the seal member (see arrow F shown in FIG. 11A), the seal member is damaged by biting foreign matter contained in the muddy water. There was a concern that it would wear out. That is, there is a problem that the sealing property of the sealing member is lowered.

Therefore, the wheel bearing device described in Patent Document 2 includes a weir member that is externally fitted to the outer member so as to prevent muddy water from traveling through the outer member and reaching the seal member. However, in such a wheel bearing device, muddy water may get over the weir member and reach the seal member (see arrow F shown in FIG. 11B), and there is a concern that the seal member may be damaged or worn. was there. That is, there is a problem that the sealing property of the sealing member is lowered.

In addition, when the vehicle body is turning, a large load is applied to the wheels of the vehicle body outside the turning direction (the left wheel in the case of right turning and the right wheel in the case of left turning). Then, a large load is also applied to the wheel bearing device that supports the wheels on the outer side in the turning direction. Further, the outer member constituting the wheel bearing device has no choice but to have a thinner wall thickness on the outer side due to the shape (draft) of the forging mold, and an enlarged diameter portion is formed at the outer end side. .. Therefore, the rigidity of the outer member is lower on the outer side than on the inner side. Therefore, when a large load is applied to the wheel bearing device, the outer end of the outer member is deformed into a substantially elliptical shape, and the roundness of the rolling surface (outer rolling surface) deteriorates. there were.

Japanese Unexamined Patent Publication No. 2014-219100 Japanese Unexamined Patent Publication No. 2011-7272

An object of the present invention is to provide a wheel bearing device capable of preventing the problem of deterioration of the sealing property of the sealing member and suppressing deterioration of the roundness of the outer rolling surface. An object of the present invention is to provide a wheel bearing device capable of preventing damage to the rolling element and its rolling surface (outer rolling surface) and preventing a decrease in bearing life.

The first invention is
An outer member with a double row of outer rolling surfaces formed on the inner circumference,
A hub ring having a small-diameter step extending in the axial direction and at least one inner ring press-fitted into the small-diameter step of the hub ring. The inner member on which the inner rolling surface is formed and
In a wheel bearing device including a double-row rolling element rotatably interposed between the rolling surfaces of the outer member and the inner member.
A drainage groove having a substantially annular shape centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the outer side.
A substantially ring-shaped thick portion centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the outer side of the drainage groove.
The thick portion has a portion that becomes an oblique side in its axial cross section, and the oblique side is inclined so as to descend from the outer side to the inner side.

The second invention is the wheel bearing device according to the first invention.
The thick portion has an inclination of the hypotenuse of the inner member with respect to the rotation axis of 5 ° or more.

The third invention is the wheel bearing device according to the first or second invention.
The thick portion has a height of 3 mm or more from the lowest portion of the drainage groove to the upper side.

The fourth invention is the wheel bearing device according to any one of the first to third inventions.
The thick portion has a thickness of 6.5 mm or more from the outer rolling surface formed on the outer side of the outer member to the outer circumference.

The fifth invention is the wheel bearing device according to any one of the first to fourth inventions.
A thin portion having a substantially annular shape centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the inner side of the drainage groove.
The thin portion has a depth of 1 mm or more from the outer circumference of the outer rolling surface formed on the outer side of the outer member.

The sixth invention is the wheel bearing device according to any one of the first to fifth inventions.
The thick portion is provided to a range in which the upper side extends axially beyond the deepest groove bottom portion of the outer rolling surface formed from the outer side end portion of the outer member to the outer side. ..

As the effect of the present invention, the following effects are exhibited.

In the wheel bearing device according to the present invention, a substantially annular drainage groove centered on the rotation axis of the inner member is provided on the outer circumference of the outer member on the outer side, and the outer member is on the outer side of the drainage groove of the outer member. A substantially ring-shaped thick portion centered on the rotation axis of the inner member is provided on the outer circumference of the inner member. The thick portion has a portion that becomes a hypotenuse in its axial cross section, and the hypotenuse is inclined so as to descend from the outer side to the inner side. According to such a wheel bearing device, since the thick portion blocks the muddy water and guides it to the drainage groove, the muddy water is prevented from reaching the seal member through the outer member, and the sealability of the seal member is lowered. Can be dispelled. Further, since a thick portion is provided on the outer peripheral surface of the outer member on the outer side, the amount of deformation of the outer side opening end of the outer member is reduced, and the roundness of the outer rolling surface can be suppressed from deteriorating. it can. As a result, damage to the rolling element and its outer rolling surface can be prevented, and the bearing life can be prevented from being shortened.

In the wheel bearing device according to the present invention, the thickness of the thick portion has an inclination of the hypotenuse of the inner member with respect to the rotation axis of 5 ° or more. According to such a bearing device for wheels, it becomes difficult for muddy water to get over the thick portion, so that it is possible to prevent the muddy water from reaching the seal member through the outer member, and it is possible to eliminate the concern that the sealability of the seal member is deteriorated. ..

In the wheel bearing device according to the present invention, the thick portion has a height of 3 mm or more from the lowest portion to the upper side of the drainage groove. According to such a bearing device for wheels, it becomes difficult for muddy water to get over the thick portion, so that it is possible to prevent the muddy water from reaching the seal member through the outer member, and it is possible to eliminate the concern that the sealability of the seal member is deteriorated. ..

In the wheel bearing device according to the present invention, the thick portion has a thickness of 6.5 mm or more from the outer rolling surface formed on the outer side of the outer member to the outer circumference. According to such a bearing device for wheels, the rigidity of the outer rolling surface formed on the outer side of the outer member is improved, so that deterioration of the roundness of the outer rolling surface can be suppressed.

In the wheel bearing device according to the present invention, the thin portion has a depth of 1 mm or more from the outer circumference of the outer rolling surface formed on the outer side of the outer member. According to such a wheel bearing device, it is possible to minimize the weight increase due to the provision of the thick portion while ensuring the rigidity of the outer member.

In the wheel bearing device according to the present invention, the thick portion is provided to a range in which the upper side exceeds the deepest groove bottom portion of the outer rolling surface formed on the outer side from the outer side end portion of the outer member in the axial direction. ing. According to such a bearing device for wheels, the rigidity from the outer side end portion of the outer member to the outer rolling surface formed on the outer side is improved, so that deterioration of the roundness of the outer rolling surface is suppressed. be able to.

The perspective view which shows the whole structure of the bearing device for a wheel. The cross-sectional view which shows the whole structure of the bearing device for a wheel. An enlarged cross-sectional view showing a partial structure of a wheel bearing device. An enlarged cross-sectional view showing a partial structure of a wheel bearing device. The enlarged sectional view which shows the main part structure of the wheel bearing apparatus which is 1st Embodiment. The figure which shows the replacement work of a hub bolt. The figure which shows the influence which the inclination angle has on the muddy water resistance performance. The figure which shows the influence which the height dimension has on the muddy water resistance performance. FIG. 3 is an enlarged cross-sectional view showing a main structure of a wheel bearing device according to a second embodiment. FIG. 5 is an enlarged cross-sectional view showing a main structure of a wheel bearing device according to a third embodiment. An enlarged cross-sectional view showing a partial structure of a conventional wheel bearing device.

Hereinafter, the wheel bearing device 1 according to the present invention will be described with reference to FIGS. 1 to 4. Note that FIG. 2 is a cross-sectional view taken along the line AA in FIG. 3 and 4 are enlarged views of a part of the region in FIG.

The wheel bearing device 1 rotatably supports wheels in a suspension device such as an automobile. The wheel bearing device 1 includes an outer member 2, an inner member 3 (hub wheel 4 and inner ring 5), a rolling element 6, a seal member 7 (hereinafter referred to as “inner side seal member 7”), and a seal. A member 10 (hereinafter referred to as "outer side seal member 10") is provided. Here, the inner side represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body, and the outer side represents the wheel side of the wheel bearing device 1 when attached to the vehicle body.

The outer member 2 constitutes an outer ring portion of the rolling bearing structure. The outer member 2 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C formed in a substantially cylindrical shape. A diameter-expanded portion 2a is formed at the inner end of the outer member 2. Further, a diameter-expanded portion 2b is formed at the outer side end portion of the outer member 2. Further, between the diameter-expanded portion 2a and the diameter-expanded portion 2b, the outer rolling surface 2c and the outer rolling surface 2d are formed in an annular shape so as to be parallel to each other. The outer rolling surface 2c and the outer rolling surface 2d are induction hardened and hardened so that the surface hardness is in the range of 58 to 64 HRC. A knuckle mounting flange 2e is integrally formed on the outer periphery of the outer member 2. The knuckle mounting flange 2e is provided with tap holes 2f arranged in the circumferential direction on a concentric circle centered on the rotation axis L of the inner member 3 (hub ring 4 and inner ring 5).

The inner member 3 constitutes an inner ring portion of the rolling bearing structure. The inner member 3 is composed of a hub ring 4 and an inner ring 5.

The hub ring 4 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C formed in a substantially cylindrical shape. A small diameter step portion 4a is formed at the inner end portion of the hub ring 4. The small diameter step portion 4a is formed with a caulking portion 4b that fixes the axial position of the inner ring 5 by bending its end portion outward in the radial direction. Further, an opening 4c is formed at the outer end of the hub ring 4. Further, an inner rolling surface 4d is formed in an annular shape on the outer circumference of the hub ring 4. The inner rolling surface 4d faces the outer rolling surface 2d of the outer member 2. The hub ring 4 is induction hardened from the small diameter step portion 4a through the inner rolling surface 4d to the seal land portion (composed of the shaft surface portion 4e, the curved surface portion 4f, and the side surface portion 4g, which will be described later), and the surface is hardened. It is hardened so that the value is in the range of 58 to 64 HRC. A wheel mounting flange 4h is integrally formed on the outer periphery of the hub wheel 4. The wheel mounting flange 4h is provided with bolt holes 4i arranged concentrically with respect to the rotation axis L of the inner members 3 (hub wheels 4 and inner rings 5) in the circumferential direction, and the hub bolts 40 are provided in the respective bolt holes 4i. Is press-fitted.

The inner ring 5 is made of high carbon chrome bearing steel such as SUJ2 formed in a substantially cylindrical shape. An inner rolling surface 5a is formed in an annular shape on the outer circumference of the inner ring 5. That is, the inner ring 5 is fitted to the small diameter step portion 4a of the hub ring 4, and forms an inner rolling surface 5a on the outer periphery of the small diameter step portion 4a. The inner rolling surface 5a faces the outer rolling surface 2c of the outer member 2. The inner ring 5 is so-called stub-quenched and hardened so as to have a core portion in the range of 58 to 64 HRC.

The rolling element 6 constitutes a rolling portion of the rolling bearing structure. The rolling element 6 is made of high carbon chrome bearing steel such as SUJ2. The ball row 6a is formed by holding a plurality of rolling elements 6 in an annular shape by a cage. The ball row 6a is rotatably accommodated between the inner rolling surface 5a formed on the inner ring 5 and the outer rolling surface 2c of the outer member 2 facing the inner rolling surface 5a. On the other hand, the ball train 6b also has a plurality of rolling elements 6 held in an annular shape by a cage. The ball row 6b is rotatably accommodated between the inner rolling surface 4d formed on the hub wheel 4 and the outer rolling surface 2d of the outer member 2 facing the inner rolling surface 4d. The rolling elements 6 of the ball row 6a and the ball row 6b are so-called stub-quenched and hardened so as to have a core portion in the range of 58 to 64 HRC.

The inner side sealing member 7 seals the inner side end portion of the annular space S formed between the outer member 2 and the inner member 3. The inner side sealing member 7 is composed of an annular slinger 8 and an annular sealing ring 9.

The slinger 8 is fitted (outerly fitted) to the outer circumference of the inner ring 5.

The slinger 8 is composed of a ferritic stainless steel sheet (JIS standard SUS430 series, etc.), an austenitic stainless steel sheet (JIS standard SUS304 series, etc.), or a rust-preventive cold-rolled steel sheet (JIS standard SPCC series, etc.). Has been done. The slinger 8 is formed in a shape in which a steel plate cut out in an annular shape is bent by press working and the axial cross section is bent at a right angle. As a result, the slinger 8 is formed with a cylindrical fitting portion 8a and a disc-shaped side plate portion 8b extending from the end portion thereof toward the outer member 2. The fitting portion 8a and the side plate portion 8b intersect each other perpendicularly, and the fitting portion 8a is press-fitted along the outer peripheral surface of the inner ring 5. Further, the side plate portion 8b extends toward the outer member 2 and faces the side plate portion 91b of the core metal 91 described later.

The seal ring 9 is fitted (innerly fitted) to the enlarged diameter portion 2a of the outer member 2. The seal ring 9 is composed of a core metal 91 and a seal rubber 92 which is an elastic member.

The core metal 91 is a ferritic stainless steel plate (JIS standard SUS430 series, etc.), an austenitic stainless steel plate (JIS standard SUS304 series, etc.), or a rust-preventive cold-rolled steel plate (JIS standard SPCC series, etc.). It is configured. The core metal 91 is formed in a shape in which a steel plate cut out in an annular shape is bent by press working and the axial cross section is bent at a right angle. As a result, the core metal 91 is formed with a cylindrical fitting portion 91a and a disc-shaped side plate portion 91b extending from the end portion toward the inner member 3 (inner ring 5). The fitting portion 91a and the side plate portion 91b intersect with each other substantially vertically, and the fitting portion 91a is press-fitted along the inner peripheral surface of the diameter-expanded portion 2a. Further, the side plate portion 91b extends toward the inner member 3 (inner ring 5) and faces the side plate portion 8b of the slinger 8 described above. A seal rubber 92, which is an elastic member, is vulcanized and adhered to the fitting portion 91a and the side plate portion 91b.

The seal rubber 92 includes NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile / butadiene rubber) with excellent heat resistance, EPDM (ethylene propylene rubber), ACM (polyacrylic rubber) with excellent heat resistance and chemical resistance, and It is composed of synthetic rubber such as FKM (fluororubber) or silicon rubber. The seal rubber 92 is formed with a radial lip 92a, an inner axial lip 92b, and an outer axial lip 92c, which are seal lips. Further, the seal rubber 92 is formed with an edge seal portion 92d so as to wrap around the fitting portion 91a of the core metal 91.

In this way, the inner side seal member 7 is arranged so that the slinger 8 and the seal ring 9 face each other. At this time, the radial lip 92a comes into contact with the fitting portion 8a of the slinger 8 via the oil film. Further, the inner axial lip 92b contacts the side plate portion 8b of the slinger 8 via the oil film. Then, the outer axial lip 92c also comes into contact with the side plate portion 8b of the slinger 8 via the oil film. In this way, the inner side sealing member 7 prevents the intrusion of muddy water and the like and prevents the leakage of grease. It should be noted that the edge seal portion 92d is formed by water entering the fitting portion between the outer member 2 and the core metal 91 (pointing to the portion where the outer member 2 and the core metal 91 are in contact with each other: the same applies hereinafter). It is designed so that it will not corrode.

The outer side sealing member 10 seals the outer side end portion of the annular space S formed between the outer member 2 and the inner member 3. The outer side seal member 10 is composed of an annular seal ring 11.

The seal ring 11 is fitted (innerly fitted) to the enlarged diameter portion 2b of the outer member 2. The seal ring 11 is composed of a core metal 111 and a seal rubber 112 which is an elastic member.

The core metal 111 is a ferritic stainless steel plate (JIS standard SUS430 series, etc.), an austenitic stainless steel plate (JIS standard SUS304 series, etc.), or a rust-preventive cold-rolled steel plate (JIS standard SPCC series, etc.). It is configured. The core metal 111 is formed in a shape in which a steel plate cut out in an annular shape is bent by press working and the axial cross section is complicatedly bent. As a result, the core metal 111 is formed with a cylindrical fitting portion 111a and a disc-shaped side plate portion 111b extending from one end thereof toward the inner member 3 (hub ring 4). The fitting portion 111a and the side plate portion 111b intersect with each other while being curved, and the fitting portion 111a is press-fitted along the inner peripheral surface of the enlarged diameter portion 2b. Further, the side plate portion 111b extends toward the inner member 3 (hub ring 4) and faces the curved surface portion 4f and the side surface portion 4g of the hub ring 4. A seal rubber 112, which is an elastic member, is vulcanized and adhered to the fitting portion 111a and the side plate portion 111b.

The seal rubber 112 includes NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber) with excellent heat resistance, EPDM (ethylene propylene rubber), ACM (polyacrylic rubber) with excellent heat resistance and chemical resistance, and It is composed of synthetic rubber such as FKM (fluororubber) or silicon rubber. The seal rubber 112 is formed with a radial lip 112a, an inner axial lip 112b, and an outer axial lip 112c, which are seal lips. Further, the seal rubber 112 is formed with an edge seal portion 112d so as to be in contact with the inner circumference of the enlarged diameter portion 2b.

In this way, the outer side seal member 10 is arranged so that the seal ring 11 and the hub ring 4 face each other. At this time, the radial lip 112a comes into contact with the shaft surface portion 4e of the hub ring 4 via the oil film. Further, the axial lip 112b comes into contact with the curved surface portion 4f of the hub ring 4 via the oil film. Then, the outer axial lip 112c also comes into contact with the side surface portion 4g of the hub ring 4 via the oil film. In this way, the outer side sealing member 10 prevents the intrusion of muddy water and the like and prevents the leakage of grease. It should be noted that the edge seal portion 112d is formed so that water does not enter the fitting portion between the outer member 2 and the core metal 111 (pointing to the portion where the outer member 2 and the core metal 111 are in contact) and corrode. It is considered as follows.

Next, the main structure of the wheel bearing device 1 according to the first embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is an enlarged view of the region R in FIG. FIG. 6 shows the replacement work of the hub bolt 40.

In the wheel bearing device 1 of the first embodiment, the outer member 2 has a substantially cylindrical shape centered on the rotation axis L of the inner member 3 (hub wheel 4 and inner ring 5). A drainage groove 2g having a substantially annular shape centered on the rotation axis L of the inner member 3 is provided on the outer periphery of the outer member 2 on the outer side. Further, on the outer periphery of the outer member 2 on the outer side of the drainage groove 2g, a substantially annular thick portion 2h centered on the rotation axis L of the inner member 3 is provided. That is, a drainage groove 2g is formed over the entire circumference of the outer member 2 on the outer side, and a thick portion 2h is formed over the entire circumference on the outer side of the drainage groove 2g. However, the drainage groove 2g and the thick portion 2h do not have to be a perfect annular shape, and may lack a part in the circumferential direction. For example, it may be missing on the lower half side of the outer member 2.

Here, the drainage groove 2g has a substantially rectangular shape or a substantially arc shape in its axial cross section. Further, the thick portion 2h has a substantially trapezoidal cross section in the axial direction, and of the substantially trapezoidal upper side 2i and the hypotenuse 2j, the hypotenuse 2j is inclined so as to descend from the outer side to the inner side. .. Therefore, the muddy water flows down to the drainage groove 2g without being transmitted to the thick portion 2h (see the arrow Fa shown in FIG. 5), and also flows down to the drainage groove 2g along the inclined surface 2j of the thick portion 2h (see the arrow Fa shown in FIG. 5). (See arrow Fb shown in FIG. 5). Further, the cross section in the axial direction may be a substantially triangular shape other than a substantially trapezoidal shape.

By the way, in the thick portion 2h, the inclination of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 is 5 ° or more. This is a result found by an experiment with the inclination angle θ of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water overcomes the thick portion 2h and the amount of muddy water that has overcome using the outer members 2 having different inclination angles θ. .. As shown in FIG. 7, the horizontal axis is the inclination angle θ, the vertical axis is the muddy water resistance performance ratio (when “1”, the performance is the same as the conventional one, and when the value is larger than “1”, the conventional one. It can be seen that when the tilt angle θ is 5 ° or more, the performance is remarkably improved. It should be noted that the inclination angle θ of 5 ° or more is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

Further, the wall thickness portion 2h has a height of 3 mm or more from the bottommost portion of the drainage groove 2g to the upper side 2i. This is a result found by an experiment with the height dimension H from the bottommost portion of the drainage groove 2g to the upper side 2i as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water exceeds the thick portion 2h and the amount of muddy water that has been overcome by using the outer members 2 having different height dimensions H. is there. As shown in FIG. 8, the horizontal axis is the height dimension H, and the vertical axis is the muddy water resistance performance ratio (when “1”, it indicates that the performance is the same as the conventional one, and if the value is larger than “1”. It can be seen that the height dimension H is remarkably improved when the height dimension H is 3 mm or more. The height dimension H of 3 mm or more is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

As described above, the wheel bearing device 1 is provided with a substantially ring-shaped drainage groove 2g centered on the rotation axis L of the inner member 3 on the outer circumference of the outer member 2 on the outer side, and the outer member 2 A substantially ring-shaped thick portion 2h centered on the rotation axis L of the inner member 3 is provided on the outer periphery on the outer side of the drainage groove 2g. The thick portion 2h has a substantially trapezoidal cross section in the axial direction, and of the substantially trapezoidal upper side 2i and the hypotenuse 2j, the hypotenuse 2j is inclined so as to descend from the outer side to the inner side. .. According to the wheel bearing device 1, the thick portion 2h dams the muddy water and guides it to the drainage groove 2g, so that the muddy water reaches the seal member 10 (outer side seal member 10) through the outer member 2. This can be prevented and the concern that the sealing property of the sealing member (10) is deteriorated can be eliminated. Further, since the thick portion 2h is provided on the outer peripheral surface of the outer member 2 on the outer side, the amount of deformation of the outer side opening end of the outer member 2 is reduced, and the roundness of the outer rolling surface 2d is deteriorated. Can be suppressed. As a result, damage to the rolling element 6 and its outer rolling surface 2d can be prevented, and a decrease in bearing life can be prevented.

Further, in the thick portion 2h, the inclination of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 is 5 ° or more. According to the wheel bearing device 1, it becomes difficult for the muddy water to get over the thick portion 2h, so that the muddy water is prevented from reaching the seal member 10 (outer side seal member 10) through the outer member 3 and the seal member. The concern that the sealing property of (10) is lowered can be dispelled.

Further, the wall thickness portion 2h has a height of 3 mm or more from the bottommost portion of the drainage groove 2g to the upper side 2i. According to the wheel bearing device 1, it becomes difficult for the muddy water to get over the thick portion 2h, so that the muddy water is prevented from reaching the seal member 10 (outer side seal member 10) through the outer member 2 and the seal member. The concern that the sealing property of (10) is lowered can be dispelled.

In addition, the thick portion 2h has a guide groove 2k of the hub bolt 40 formed on the outer edge portion thereof. More specifically, the outer edge portion of the thick portion 2h is cut out in an arc shape, so that a guide groove 2k for passing the hub bolt 40 is formed.

With such a design, the bearing device 1 for this wheel has the outer member 2 and the inner member 3 even if the height dimension of the thick portion 2h is increased in consideration of making it difficult for muddy water to get over. The hub bolt 40 can be replaced without disassembling the wheel.

In addition, the wheel bearing device 1 has five hub bolts 40, each of which is provided at a position where the phase angle about the rotation axis L is every 72 °. Therefore, on the outer edge portion of the thick portion 2h, five guide grooves 2k are formed in the circumferential direction at positions where the phase angles around the rotation axis L are every 72 °. However, guide grooves 2k may be provided at 10 places which are multiples. At this time, the guide grooves 2k are formed at positions where the phase angles around the rotation axis L are every 36 °. Further, the wheel bearing device 1 has five hub bolts 40, but for example, it is assumed that it has four hub bolts 40, and each of them is provided at a position where the phase angle about the rotation axis L is 90 °. May be. In this case, the four guide grooves 2k are formed at positions where the phase angles around the rotation axis L are every 90 °. However, guide grooves 2k may be provided at eight locations that are multiples.

With such a design, the bearing device 1 for this wheel can superimpose the positions of all the hub bolts 40 on all the guide grooves 2k, so that the hub bolts 40 can be easily replaced.

Next, the main part structure of the wheel bearing device 1 according to the second embodiment will be described with reference to FIG. FIG. 9 corresponds to an enlarged view of the region R in FIG.

Also in the wheel bearing device 1 according to the second embodiment, a substantially annular drainage groove 2g and a thick portion 2h are provided on the outer peripheral side of the outer member 2 on the outer side. The drainage groove 2g has a substantially rectangular or substantially arcuate cross section in the axial direction. Further, the thick portion 2h has a substantially trapezoidal cross section in the axial direction, and of the substantially trapezoidal upper side 2i and the hypotenuse 2j, the hypotenuse 2j is inclined so as to descend from the outer side to the inner side. .. However, in the present embodiment, the hypotenuse 2j is formed on the outer circumference at the bottommost portion of the outer rolling surface 2d (pointing to the outer circumference intersecting the virtual line extending radially outward from the bottommost portion of the outer rolling surface 2d). There is.

By the way, in the thick portion 2h, the inclination angle θ of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 is 5 ° or more. This is a result found by an experiment with the inclination angle θ of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water overcomes the thick portion 2h and the amount of muddy water that has overcome the outer members 2 having different inclination angles θ. .. It is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

Further, the wall thickness portion 2h has a height of 3 mm or more from the bottommost portion of the drainage groove 2g to the upper side 2i. This is a result found by an experiment with the height dimension H from the bottommost portion of the drainage groove 2g to the upper side 2i as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water exceeds the thick portion 2h and the amount of muddy water that has been overcome by using the outer members 2 having different height dimensions H. is there. It is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

Therefore, also in the wheel bearing device 1 of the second embodiment, as in the wheel bearing device 1 of the first embodiment, the thick portion 2h dams the muddy water and guides it to the drainage groove 2g. It is possible to prevent muddy water from reaching the seal member 10 (outer side seal member 10) through the outer member 2 and eliminate the concern that the sealability of the seal member (10) is deteriorated. Further, since the thick portion 2h is provided on the outer peripheral surface of the outer member 2 on the outer side, the amount of deformation of the outer side opening end of the outer member 2 is reduced, and the roundness of the outer rolling surface 2d is deteriorated. Can be suppressed. As a result, damage to the rolling element 6 and its outer rolling surface 2d can be prevented, and a decrease in bearing life can be prevented.

Further, the wall thickness portion 2h is the height from the bottommost portion of the outer rolling surface 2d to the outer circumference at the bottommost portion (pointing to the outer circumference intersecting the virtual line extending radially outward from the bottommost portion of the outer rolling surface 2d). The height is 6.5 mm or more. This is a result found by analysis with the thickness dimension T from the bottommost portion of the outer rolling surface 2d to the outer circumference at the bottommost portion as a parameter. More specifically, it is the result found by the analysis of measuring the amount of deformation on the outer rolling surface 2d using the outer members 2 having different thickness dimensions T.

As described above, in the wheel bearing device 1, the wall thickness portion 2h has a thickness from the bottommost portion of the outer rolling surface 2d formed on the outer side of the outer member 2 to the outer circumference at the bottommost portion. It is 5 mm or more. According to the wheel bearing device 1, the rigidity of the outer rolling surface 2d formed on the outer side of the outer member 2 is improved, so that deterioration of the roundness of the outer rolling surface 2d can be suppressed. it can.

Further, in the present embodiment, a substantially ring-shaped thin portion 2m centered on the rotation axis L of the inner member 3 is provided on the outer periphery on the inner side of the drainage groove 2g of the outer member 2. The thin portion 2 m has a depth of 1 mm or more from the outer circumference at the bottom of the outer rolling surface 2d (pointing to the outer circumference intersecting the virtual line extending radially outward from the bottom of the outer rolling surface 2d). .. This is the result found by analysis with the depth dimension D from the outer circumference at the bottom of the outer rolling surface 2d as a parameter. More specifically, it is the result found by the analysis of measuring the amount of deformation in the thin portion 2 m using the outer members 2 having different thickness dimensions T.

As described above, in the wheel bearing device 1, the thin portion 2 m has a depth of 1 mm or more from the outer circumference at the bottommost portion of the outer rolling surface 2d. According to the wheel bearing device 1, it is possible to minimize the weight increase due to the provision of the thick portion 2h while ensuring the rigidity of the outer member 2.

Next, the main part structure of the wheel bearing device 1 according to the third embodiment will be described with reference to FIG. FIG. 10 corresponds to an enlarged view of the region R in FIG.

Also in the wheel bearing device 1 according to the third embodiment, a substantially annular drainage groove 2g and a thick portion 2h are provided on the outer peripheral side of the outer member 2 on the outer side. The drainage groove 2g has a substantially rectangular or substantially arcuate cross section in the axial direction. Further, the thick portion 2h has a substantially trapezoidal cross section in the axial direction, and of the substantially trapezoidal upper side 2i and the hypotenuse 2j, the hypotenuse 2j is inclined so as to descend from the outer side to the inner side. .. However, in the present embodiment, the upper side 2i is formed on the outer circumference at the bottommost portion of the outer rolling surface 2d (pointing to the outer circumference intersecting the virtual line extending radially outward from the bottommost portion of the outer rolling surface 2d). There is.

By the way, in the thick portion 2h, the inclination angle θ of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 is 5 ° or more. This is a result found by an experiment with the inclination angle θ of the hypotenuse 2j with respect to the rotation axis L of the inner member 3 as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water overcomes the thick portion 2h and the amount of muddy water that has overcome using the outer members 2 having different inclination angles θ. .. It is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

Further, the wall thickness portion 2h has a height of 3 mm or more from the bottommost portion of the drainage groove 2g to the upper side 2i. This is a result found by an experiment with the height dimension H from the bottommost portion of the drainage groove 2g to the upper side 2i as a parameter. Specifically, it is a result found by an experiment of measuring whether or not a certain amount of muddy water exceeds the thick portion 2h and the amount of muddy water that has been overcome by using the outer members 2 having different height dimensions H. is there. It is also a result found by an analysis for measuring the amount of deformation of the outer end of the outer member 2.

Therefore, also in the wheel bearing device 1 of the third embodiment, as in the wheel bearing device 1 of the first embodiment, the thick portion 2h dams the muddy water and guides it to the drainage groove 2g. It is possible to prevent muddy water from reaching the seal member 10 (outer side seal member 10) through the outer member 2 and eliminate the concern that the sealability of the seal member (10) is deteriorated. Further, since the thick portion 2h is provided on the outer peripheral surface of the outer member 2 on the outer side, the amount of deformation of the outer side opening end of the outer member 2 is reduced, and the roundness of the outer rolling surface 2d is deteriorated. Can be suppressed. As a result, damage to the rolling element 6 and its outer rolling surface 2d can be prevented, and a decrease in bearing life can be prevented.

Further, the thick portion 2h is a virtual range in which the upper side 2i extends from the outer side end portion of the outer member 2 to the bottom portion of the outer rolling surface 2d (extended radially outward from the bottommost portion of the outer rolling surface 2d). It is provided up to the range beyond the line). This is intended to improve the rigidity of the outer member 2 on the outer side.

As described above, in the wheel bearing device 1, the thick portion 2h is provided to a range where the upper side 2i exceeds the bottommost portion of the outer rolling surface 2d formed from the outer side end portion of the outer member 2 to the outer side. Has been done. According to the wheel bearing device 1, the rigidity of the outer member 2 from the outer side end portion to the outer rolling surface 2d formed on the outer side is improved, so that the roundness of the outer rolling surface 2d is deteriorated. It can be suppressed.

1 Wheel bearing device 2 Outer member 2c Outer rolling surface 2d Outer rolling surface 2g Drainage groove 2h Thick part 2i Upper side 2j Hypotenuse 2k Guide groove 2m Thin part 3 Inner member 4 Hub wheel 4a Small diameter step part 4d Inward rotation Running surface 5 Inner ring 5a Inner rolling surface 6 Rolling element 6a Ball row 6b Ball row 7 Sealing member 8 Slinger 9 Sealing ring 10 Sealing member 11 Sealing ring 40 Hub bolt L Rotating shaft of inner member

Claims (5)

An outer member with a double row of outer rolling surfaces formed on the inner circumference,
A hub ring having a small-diameter step extending in the axial direction and at least one inner ring press-fitted into the small-diameter step of the hub ring. The inner member on which the inner rolling surface is formed and
In a wheel bearing device including a double-row rolling element rotatably interposed between the rolling surfaces of the outer member and the inner member.
A drainage groove having a substantially annular shape centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the outer side.
A substantially ring-shaped thick portion centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the outer side of the drainage groove.
The thick portion has a portion that becomes an upper side and an oblique side in the axial cross section thereof, the oblique side is inclined so as to descend from the outer side to the inner side , and the upper side is the outer side of the outer member. A wheel bearing device characterized in that it is provided to a range that exceeds the deepest portion of the groove bottom of the outer rolling surface formed on the outer side from the end portion in the axial direction . The wheel bearing device according to claim 1, wherein the thick portion has an inclination of the hypotenuse of the inner member with respect to the rotation axis of 5 ° or more. The wheel bearing device according to claim 1 or 2, wherein the thick portion has a height of 3 mm or more from the bottommost portion of the drainage groove to the upper side thereof. Any of claims 1 to 3, wherein the thick portion has a thickness of 6.5 mm or more from the outer rolling surface formed on the outer side of the outer member to the outer circumference. The wheel bearing device according to claim 1. A thin portion having a substantially annular shape centered on the rotation axis of the inner member is provided on the outer periphery of the outer member on the inner side of the drainage groove.
The thin portion is characterized in that the depth from the outer periphery of the outer rolling surface formed on the outer side of the outer member is 1 mm or more and the thickness is thicker than the bottommost portion of the drainage groove. The wheel bearing device according to any one of claims 1 to 4.

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