JP2013019529A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, which suppresses an increase in a bearing inner pressure induced upon press-fitting a protective cover and absorbs changes in the inner pressure of the bearing to secure sealing property of a seal, and improves precision and reliability of detection of a rotational speed.SOLUTION: In the bearing device for a wheel, a protective cover 10 is formed into a cup shape by press-machining a non-magnetic austenitic stainless steel plate. The protective cover includes: a cylindrical fitting part 10a which is press-fitted into the end inner circumference of an outside member 2; a disk-like shielding part 10b which extends inward in a radial direction from the fitting part 10a and where a rotational speed sensor 15 is brought into contact with or close to the side face thereof in the inner side; and a bottom part 10d, as continuing from the shielding part 10b via a bent part 10c, which closes an end in the inner side of an inside member 1. A through-hole 16 is formed in the center part of the bottom part 10d; and a sealing member 17 made of synthetic rubber is joined to the through-hole 16 to close the through-hole 16. Elastic force of the sealing member 17 is set to be lower than elastic force of a seal 9.

Description

  The present invention relates to a wheel bearing device equipped with a protective cover for rotatably supporting a wheel of an automobile or the like and sealing the inside of the bearing.

  There is provided a wheel bearing device in which a rotation speed detection device for detecting a rotation speed of a vehicle and controlling an anti-lock brake system (ABS) is incorporated in the bearing while rotatably supporting a vehicle wheel with respect to a suspension device. Generally known. Conventionally, in such a wheel bearing device, a sealing device is provided between an inner member and an outer member that are in rolling contact with a rolling element, and a magnetic encoder in which magnetic poles are alternately arranged in a circumferential direction is provided as the sealing device. It is integrated with. A rotational speed sensor that is arranged facing this magnetic encoder and detects a change in magnetic pole of the magnetic encoder accompanying the rotation of the wheel is mounted on the knuckle after the wheel bearing device is mounted on the knuckle constituting the suspension device. .

  A structure as shown in FIG. 10 is known as an example of such a wheel bearing device. The wheel bearing device includes an outer member 50, an inner member 51, and a plurality of balls 52 accommodated between the outer member 50 and the inner member 51. The inner member 51 includes a hub ring 53 and an inner ring 54 press-fitted into the hub ring 53.

  The outer member 50 integrally has a vehicle body mounting flange 50b fixed to a knuckle (not shown) constituting a suspension device on the outer periphery, and double row outer rolling surfaces 50a and 50a are integrally formed on the inner periphery. Has been.

  The hub wheel 53 integrally has a wheel mounting flange 55 for mounting a wheel (not shown) at one end, an inner rolling surface 53a on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface 53a. A portion 53b is formed. The inner ring 54 has an inner rolling surface 54a formed on the outer periphery, and is fixed in the axial direction by a caulking portion 53c formed by plastically deforming an end portion of the small diameter step portion 53b.

  A seal ring 56 is fitted and fixed to the outer end portion of the outer member 50, and the lip of the seal ring 56 is in sliding contact with the base portion 55 a of the wheel mounting flange 55. On the other hand, an encoder 57 is fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 54. The encoder 57 includes a support ring 58 having an L-shaped cross section, and an encoder body 59 that is attached to and supported on the side surface of the support ring 58 over the entire circumference. In the encoder body 59, magnetic poles N and S are alternately magnetized at equal intervals in the circumferential direction.

  The inner end opening of the outer member 50 is closed by the cover 60. The cover 60 is formed from a nonmagnetic plate material such as a nonmagnetic stainless steel plate, aluminum alloy plate, or high-functional resin, and is an outer peripheral cylinder that is press-fitted and fixed to the outer peripheral edge of the inner peripheral surface of the outer member 50. The portion 61, the annular flat portion 62 that faces the encoder body 59, and the bottom surface portion 63 that covers the end portion of the inner member 51 are integrally provided. The cover 60 is formed in a predetermined shape and then subjected to a demagnetization process so that the residual magnetism is preferably 3 gauss or less.

  The side surface of the encoder main body 59 constituting the encoder 57 is disposed close to and opposed to the cover 60, and the detection unit of the sensor 64 is close to or abutted with the side surface of the cover 60. It is closely opposed via the cover 60. Thereby, the presence of the cover 60 prevents water, iron powder, magnetic fragments, etc. from entering between the sensor 64 and the encoder 57, thereby preventing damage to the sensor 64 and the encoder 57, and the encoder. It is possible to prevent the regular and periodic magnetic property changes of the main body 59 from being disturbed or deteriorated (see, for example, Patent Document 1).

  Since such a cover 60 is a metal-fitting to the outer member 50, the sealing performance depends on the shape and surface roughness of the fitting surface. Therefore, in order to obtain a high sealing performance, only the cover 60 is used. In addition, the processing accuracy of the outer member 50 must be strictly suppressed.

  A cover as shown in FIG. 11 is also known. The cover 65 is formed of a nonmagnetic plate material such as a nonmagnetic stainless steel plate, an aluminum alloy plate, or a high-functional resin, and includes a cover body 66 that closes the annular space K. The outer peripheral edge of the cover body 66 is bent toward the bearing inner side. The bent portion 67 includes a conical portion 67a as a fitting portion having an annular structure that gradually decreases in diameter in the fitting direction, and a cylindrical portion as a contact portion having a constant diameter in the fitting direction from the conical portion 67a to the tip. 67b.

  The cover main body 66 is formed in a shape protruding so as to cover the inner ring 54 and the caulking portion 53c, and the bent portion 67 is press-fitted into the inner peripheral surface 69 facing the opening K at one end in the axial direction of the outer member 68. It is fitted in the state that is. The inner peripheral surface 69 has a conical portion 69a as a fitted portion having an annular structure that gradually decreases in diameter in the fitting direction, and has a constant diameter in the fitting direction on the inner side in the axial direction than the conical portion 69a. A cylindrical portion 69b as a contacted portion is formed.

  The bent portion 67 of the cover 65 is outside the inner diameter of the inner peripheral surface 69 of the outer member 68 in a state before being fitted to the inner peripheral surface 69 of the outer member 68 as indicated by a two-dot chain line. The diameter has been expanded to some extent. As a result, in a state where the conical portion 67a of the bent portion 67 of the cover 65 is press-fitted into the conical portion 69a of the inner peripheral surface 69 of the outer member 68, the conical portion 67a is elastically deformed into a reduced diameter state and expands outward. Thus, the elastic biasing force acts on the conical portion 69 a of the outer member 68. Therefore, the contact frictional force of the fitting portion 67 of the cover 65 is increased, and it acts as a position holding force in the axial direction, thereby improving the positioning accuracy.

  Moreover, in the cover 70 shown in FIG. 12, the bending part 71 is comprised by the cylinder shape. An annular convex portion 72 protruding outward in the radial direction is formed over the entire circumferential direction at a substantially central position of the axial width of the cylindrical bent portion 71. On the other hand, the inner circumferential surface 74 of the outer member 73 is formed with an annular concave groove 75 along the circumferential direction at a substantially middle portion of the width in the axial direction.

  Therefore, when the cover 70 is fitted to the outer member 73 along the axial direction, the convex portion 72 is fitted into the concave groove 75, and in a state where the convex portion 72 is fitted into the concave groove 75. And since the contact location with respect to each of the mating counterparts regulates the position in the axial direction, the positioning accuracy of the cover 70 is improved (for example, see Patent Document 2).

JP 2007-218426 A Japanese Patent No. 42444631

  However, in such a conventional wheel bearing device, when the covers 60, 65, 70 are press-fitted into the outer members 50, 68, 73, the internal pressure of the bearing is increased by the air that is pushed in, and the lip of the seal ring 56 is reversed. As a result, the frictional resistance is increased, heat generation and wear are accelerated, and the sealing performance may be lowered.

  In addition, the cover 60, 65, 70 is deformed so that the central portion thereof is raised by the internal pressure, and accordingly, there is a possibility that the fitting squeezing is reduced and the holding force (removal resistance) is lowered. Due to this decrease in holding force, when the vehicle travels, the internal pressure rises due to the temperature rise inside the bearing, and the covers 60, 65, 70 move and contact the sensor 64, and only the position of the sensor 64 itself. In addition, the air gap with the encoder 57 becomes abnormal and there is a problem that the vehicle speed cannot be detected with high accuracy.

  The present invention has been made in view of such circumstances, and suppresses an increase in bearing internal pressure that occurs when the protective cover is press-fitted, and absorbs changes in the bearing internal pressure to ensure the sealing performance of the seal. An object of the present invention is to provide a wheel bearing device with improved detection accuracy and reliability.

  In order to achieve such an object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle constituting the suspension device on the outer periphery, and double row outer rolling on the inner periphery. A hub wheel having an integrally formed outer member, a wheel mounting flange for mounting a wheel at one end, and a small-diameter step portion extending in the axial direction on the outer periphery, and the hub wheel An inner member comprising at least one inner ring press-fitted into a small-diameter step portion, and having an outer periphery formed with a double-row inner rolling surface opposite to the double-row outer rolling surface, the inner member and the outer member A plurality of rolling elements housed in a freely rolling manner between the rolling surfaces of the outer member, a seal is attached to an outer end of the outer member, and an inner member of the outer member A protective cover is attached to the end on the side, the outer member and the inner part In the wheel bearing device in which the opening of the annular space formed by the seal is sealed, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery of the end of the outer member, and the inner member. A cup having a bottom portion that closes the end on the inner side, a through hole is formed in the bottom portion, and a sealing member made of synthetic rubber is joined to the through hole to close the through hole, and The elastic force of the sealing member is set smaller than the elastic force of the seal.

  As described above, the seal is attached to the outer end portion of the outer member, and the protective cover is attached to the inner end portion of the outer member, and the annular member is formed by the outer member and the inner member. In the wheel bearing device in which the opening portion of the space is sealed, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery of the end portion of the outer member, and a bottom portion that blocks the inner end portion of the inner member. A synthetic rubber sealing member is joined to the through hole to close the through hole, and the elastic force of the sealing member is greater than the elastic force of the seal. Therefore, when the protective cover is press-fitted into the outer member, the internal pressure of the bearing is increased by the air that is pushed in, and the seal grease lip can be reliably prevented from being reversed. Changes in internal pressure Since it is difficult to apply a pressure load to the seal, the seal is prevented from being worn out or torque is increased to ensure the sealing performance of the seal, and the accuracy and reliability of rotation speed detection It is possible to provide a wheel bearing device that improves the above. In other words, since the elastic force of the sealing member is set to be smaller than the elastic force of the seal, the sealing member is more easily deformed into irregularities than the seal, and absorbs the pressure change when the bearing internal pressure during operation rises. can do.

  According to a second aspect of the present invention, the protective cover is formed of a non-magnetic material, a rotational speed sensor is brought close to or in contact with the protective cover, and a magnetic encoder is fitted on the inner ring. If this magnetic encoder and the rotational speed sensor are arranged to face each other with a predetermined air gap through the protective cover, the desired detection accuracy can be obtained without affecting the flow path of the magnetic flux, and the detection can be performed over a long period of time. The sealing performance of the part can be ensured, and the accuracy and reliability of rotation speed detection can be improved.

  Further, as in the invention described in claim 3, the protective cover may be formed from an austenitic stainless steel plate by pressing, and as in the invention described in claim 4, the protective cover is It may be formed by injection molding from a thermoplastic synthetic resin.

  According to a fifth aspect of the present invention, the protective cover includes a concave portion that bulges to the outer side at the bottom thereof, the through hole is formed in the concave portion, and the sealing member is swelled most. If the depth of the concave portion is set so as not to protrude from the bottom portion to the inner side in the state, the sealing member is reliably prevented from peeling off even if the protective cover interferes with other parts in the manufacturing process or the like. Can improve reliability.

  In addition, as in the invention described in claim 6, if the sealing member is joined by a liquid sealant having elasticity, the through hole can be closed without being peeled off, and the bearing is passed from the outside through the through hole. It is possible to prevent rainwater and dust from entering the inside.

  Further, as in the invention according to claim 7, the sealing member has an annular recess formed in an outer peripheral portion thereof, a central portion is formed thinner than the outer peripheral portion, and the annular recess is By fitting into the through hole of the protective cover, if the sealing member is integrally joined, the sealing member can be joined to the protective cover without using an adhesive simply by elastically deforming the outer periphery. In addition, the central portion of the sealing member is formed thin, so that it can be easily elastically deformed as if it is at the bottom of the beadro and follow changes in the bearing internal pressure.

  Moreover, if the sealing member is joined to the bottom portion on the outer side of the protective cover as in the invention described in claim 8, the joint portion is not exposed to the outside, so that durability can be improved. it can.

  Further, as in the invention according to claim 9, if the sealing member is formed in a diaphragm shape having concentric folds, the pressure change can be easily followed by the change in the internal pressure of the bearing. While being able to suppress, an excessive force is not applied to a junction part and durability can be improved.

  Further, as in the invention described in claim 10, if the temperature TR10 at which the sealing member exhibits a low-temperature elastic recovery rate of 10% is set to −35 ° C. or less, the flexibility of the bearing is not impaired even in a low-temperature atmosphere. It is possible to follow the change in internal pressure.

  Moreover, if the surface protecting agent which consists of a wax and an anti-aging agent is apply | coated to the said sealing member like invention of Claim 11, ozone resistance will improve and durability can be improved.

  If the sealing member is made of vinylmethylsilicone rubber as in the invention described in claim 12, a hollow needle is inserted into the sealing member after press-fitting the protective cover, and the internal pressure increased by press-fitting is increased. Even if it cancels, since the sealing member has good gas permeability, it is not necessary to remove the needle and close the hole with an adhesive, and the hole can be closed by the reaction force of the material itself.

  A wheel bearing device according to the present invention has a vehicle body mounting flange integrally attached to a knuckle constituting a suspension device on an outer periphery, and an outer side in which a double row outer rolling surface is integrally formed on an inner periphery. And a hub wheel integrally having a wheel mounting flange for mounting a wheel at one end thereof and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one press-fitted into the small-diameter step portion of the hub ring An inner member formed of two inner rings and formed on the outer periphery with a double row inner rolling surface facing the outer row rolling surface of the double row, and between the respective rolling surfaces of the inner member and the outer member A plurality of rolling elements housed in a freely rotatable manner, and a seal is attached to the outer end of the outer member, and a protective cover is attached to the inner end of the outer member. An annular space formed by the outer member and the inner member. In the wheel bearing device in which the mouth portion is sealed, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery of the end portion of the outer member, and a bottom portion that blocks the inner end portion of the inner member. A through hole is formed in the bottom, and a synthetic rubber sealing member is joined to the through hole to close the through hole, and an elastic force of the sealing member is applied to the seal. Since the pressure is less than the elastic force of the seal, it is difficult to apply a pressure load to the seal. Therefore, the seal is prevented from being worn out or torque is increased to ensure the seal tightness and to detect the rotational speed. It is possible to provide a wheel bearing device with improved accuracy and reliability.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows the protective cover single-piece | unit of FIG. (A) is explanatory drawing which shows a state when the pressure inside a bearing rises, (b) is explanatory drawing which shows a state when the pressure inside a bearing falls. (A)-(e) is a principal part enlarged view which shows the modification of the protective cover of FIG. (A), (b) is a principal part enlarged view which shows the other modification of the protective cover of FIG. (A), (b) is explanatory drawing which shows the assembly method of the protective cover of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 4th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is a principal part enlarged view which shows the detection part of the other conventional wheel bearing apparatus. It is a principal part enlarged view which shows the detection part of the other conventional wheel bearing apparatus.

  An outer member that integrally has a vehicle body mounting flange to be attached to a knuckle constituting a suspension device on the outer periphery, and an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel on one end A hub wheel integrally having a wheel mounting flange and having an inner rolling surface opposed to one of the double-row outer rolling surfaces and a small-diameter step portion extending in the axial direction from the inner rolling surface. And an inner member comprising an inner ring that is press-fitted into a small-diameter step portion of the hub wheel and has an inner rolling surface that faces the other of the outer rolling surfaces of the double row on the outer periphery, and the inner member and the A double-row rolling element accommodated between the rolling surfaces of the outer member so as to roll freely, and a magnetic encoder externally fitted to the inner ring, and the end portion of the small-diameter step portion of the hub ring being plastic In a state where a predetermined bearing preload is applied by the deformed caulking portion, The wheel is fixed in the axial direction with respect to the hub wheel, a seal is attached to the outer end of the outer member, and a protective cover is attached to the inner end of the outer member. In the wheel bearing device in which the opening of the annular space formed by the outer member and the inner member is sealed, the protective cover is formed in a cup shape by pressing from a non-magnetic austenitic stainless steel plate. A cylindrical fitting portion that is press-fitted into the inner periphery of the end portion of the outer member, and a disk that extends radially inward from the fitting portion and in which the rotational speed sensor approaches or contacts the side surface on the inner side And a bottom portion that closes the inner side end of the inner member from the shielding portion through a bent portion, and a through hole is formed in the central portion of the bottom portion, and the synthetic rubber is formed in the through hole. The sealing member made of With through hole is closed, is smaller than the elastic force of the elastic force said seal of said sealing member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is a longitudinal sectional view showing a single protective cover of FIG. 1, and FIG. FIG. 4B is an explanatory view showing a state when the pressure is increased, FIG. 4B is an explanatory view showing a state when the pressure inside the bearing is lowered, and FIGS. 4A to 4E are deformations of the sealing member of FIG. FIG. 5A and FIG. 5B are main part enlarged views showing another modification of the sealing member of FIG. 2, and FIGS. 6A and 6B are FIG. It is explanatory drawing which shows the assembly method of a protective cover. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1, outer member 2, and both members 1,2. (Balls) 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and integrally has a vehicle body mounting flange 2b for mounting to a knuckle (not shown) on the outer periphery. Double row outer rolling surfaces 2a, 2a are integrally formed. At least the double row outer raceway surfaces 2a and 2a are hardened by induction hardening in a range of 58 to 64 HRC.

  The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at an end portion on the outer side, and hub bolts 6a are implanted at circumferentially equidistant positions of the wheel mounting flange 6. Yes. Moreover, the inner side rolling surface 4a which opposes one (outer side) of the said double row outer side rolling surface 2a, 2a and the small diameter step part 4b extended in an axial direction from this inner side rolling surface 4a are formed in outer periphery. Yes. On the other hand, the inner ring 5 is formed on the outer periphery with an inner rolling surface 5a facing the other (inner side) of the double row outer rolling surfaces 2a, 2a, and a small-diameter step portion 4b of the hub wheel 4 via a predetermined shimoshiro. It is press-fitted. The inner ring 5 is fixed in the axial direction in a state where a predetermined bearing preload is applied by a crimping portion 7 formed by plastically deforming an end portion of the small-diameter stepped portion 4b of the hub wheel 4 radially outward. .

  Between the double row outer rolling surfaces 2a, 2a of the outer member 2 and the double row inner rolling surfaces 4a, 5a facing these, the double row rolling elements 3, 3 are respectively accommodated, and the cage 8 , 8 are held so as to roll freely. A seal 9 is attached to the outer opening of the annular space formed between the outer member 2 and the inner member 1, and the magnetic encoder 14 is installed to the inner opening. The protective cover 10 is mounted to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater, dust, etc. into the bearing from the outside.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 3 was illustrated here, it is not restricted to this, The double row tapered roller bearing which used the tapered roller for the rolling element 3 It may consist of. In addition, here, a third generation structure in which the inner raceway surface 4a is formed directly on the outer periphery of the hub wheel 4 is illustrated, but although not shown, the inner raceway surface has a plurality of inner rings and is directly on the hub wheel. It may be a 2.5th generation structure of a driven wheel in which is not formed.

  The hub wheel 4 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and extends from the inner raceway surface 4a to the small diameter step portion 4b from the base portion 6b on the inner side of the wheel mounting flange 6. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 7 is an unquenched portion with the surface hardness after forging. This facilitates the caulking process and prevents the occurrence of minute cracks during the process, and not only improves the wear resistance of the base part 6b that becomes the seal land part of the seal 9 on the outer side, but also the wheel mounting flange 6 It has sufficient mechanical strength with respect to the rotational bending load applied to the hub ring 4 and the durability of the hub wheel 4 is improved. The inner ring 5 and the rolling element 3 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core portion by quenching.

  In this embodiment, the seal 9 on the outer side is a core 11 formed by press working from a cold-rolled steel plate (JIS standard SPCC system or the like), and a seal that is integrally vulcanized and bonded to the core 11. Member 12. The seal member 12 is made of a synthetic rubber such as NBR (acrylonitrile-butadiene rubber), extends in a radially outward direction, and has a predetermined axis on a base portion 6b on the inner side of the wheel mounting flange 6 formed in an arc shape. The side lip 12a and the dust lip 12b that are in sliding contact with each other through the direction shimillo, and the grease lip 12c that is inclined and extends inwardly of the bearing and that is in sliding contact with the base 6b through the predetermined radial shimoshiro are integrally provided. In addition to the exemplified NBR, the material of the seal member 12 includes, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc., which have excellent heat resistance, and heat resistance and chemical resistance. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber, which are excellent in the above.

  A support ring 13 having an L-shaped cross section is fitted on the inner ring 5. The support ring 13 includes a cylindrical portion 13a that is press-fitted into the outer diameter of the inner ring 5, and a standing plate portion 13b that extends radially outward from the cylindrical portion 13a, and a magnet is formed on the inner side surface of the standing plate portion 13b. The encoder 14 is integrally joined by vulcanization adhesion. In the magnetic encoder 14, magnetic powder such as ferrite is mixed in synthetic rubber, and magnetic poles N and S are magnetized alternately at equal pitches in the circumferential direction.

  The support ring 13 is formed by press working from a ferromagnetic steel plate, for example, a ferritic stainless steel plate (JIS standard SUS430 or the like) or a rust-proof cold rolled steel plate. Thereby, the magnetic output of the magnetic encoder 14 becomes strong, and the stable detection accuracy can be ensured.

  The protective cover 10 mounted on the inner side end of the outer member 2 is formed into a cup shape by press working from a nonmagnetic austenitic stainless steel plate (such as JIS 304 SUS standard). The protective cover 10 includes a cylindrical fitting portion 10a that is press-fitted into the inner periphery of the end of the outer member 2, a disk-shaped shielding portion 10b that extends radially inward from the fitting portion 10a, and the shielding member 10a. And a bottom portion 10d that closes the inner end of the inner member 1 from the portion 10b through the bent portion 10c. Then, the rotational speed sensor 15 is brought close to or in contact with the shielding portion 10b of the protective cover 10, and the rotational speed sensor 15 and the magnetic encoder 14 are arranged to face each other with a predetermined air gap (axial clearance) through the protective cover 10. ing. Such a stepped shape increases the rigidity of the protective cover 10 and can suppress deformation due to flying stones or deformation during press-fitting, and since the protective cover 10 is non-magnetic, it does not affect the flow path of magnetic flux. It has excellent corrosion resistance and can improve durability over a long period of time.

  Here, since the magnetic encoder 14 for detecting the rotational speed is attached to the inner ring 5, the protective cover 10 is formed of a non-magnetic austenitic stainless steel plate that does not affect the flow path of the magnetic flux. When the magnetic encoder 14 is not attached to the inner ring 5, the present invention is not limited to this. For example, a ferritic stainless steel plate or a cold-rolled steel plate subjected to rust prevention may be used.

  Here, in the present embodiment, as shown in an enlarged view in FIG. 2, a through hole 16 is formed in the central portion of the bottom portion 10 d of the protective cover 10. A sealing member 17 made of synthetic rubber such as NBR is joined to the through hole 16 to close the through hole 16. The through-hole 16 may be penetrated, but is preferably formed in a circular shape. Thereby, when the sealing member 17 deform | transforms, the force concerning the junction part of the sealing member 17 becomes uniform, and durability of a junction part improves.

  The elastic force of the sealing member 17 is set to be smaller than the elastic force of the seal member 12 in the outer seal 9. As a result, when the protective cover 10 is press-fitted into the outer member 2, the internal pressure of the bearing is increased by the air that is pushed in, and the grease lip 12c of the outer seal 9 can be reliably prevented from being inverted, and Since the change in the internal pressure of the bearing can be absorbed, it is difficult to apply a pressure load to the seal 9, so that the seal 9 is prevented from being worn out or torque is increased to ensure the sealing performance of the seal 9. Thus, it is possible to provide a wheel bearing device that improves the accuracy and reliability of rotation speed detection. In addition, as an adhesive agent for joining the sealing member 17 to the protective cover 10, an epoxy resin system, a phenol resin system, a polyurethane system, a polyethylene system, etc. can be illustrated.

  In the present embodiment, a temperature TR10 (an index representing rubber elasticity) indicating a low temperature elastic recovery rate of 10% of the sealing member 17 made of synthetic rubber is set to −35 ° C. or lower. Accordingly, it is possible to follow the change in the internal pressure of the bearing without impairing flexibility even in a low temperature atmosphere. Furthermore, in order to improve ozone resistance, a wax and an anti-aging agent (surface protective agent) are blended. The wax gradually emerges on the rubber surface to form a thin film and protect the rubber surface, and the anti-aging agent can prevent a process in which the rubber and ozone react to grow into cracks.

  Since the sealing member 17 according to the present invention can absorb a change in the internal pressure of the bearing and can perform a so-called breathing motion, for example, as shown in FIG. The sealing member 17 swells to the bearing outer side (inner side) and suppresses the increase in internal pressure. On the other hand, as shown in FIG. Can be recessed to the bearing outer inner side (outer side) to suppress a decrease in internal pressure.

  4A to 4E are modified examples of the sealing member 17 described above. As for the sealing member 18 shown to (a), the annular recess 19 is formed in the outer peripheral part 18a, and the center part 18b is formed thinner than the outer peripheral part 18a. Then, the annular recess 19 is fitted into the through hole 16 of the protective cover 10, so that the sealing member 18 is integrally joined. In the present embodiment, the sealing member 18 can be joined to the protective cover 10 without using an adhesive simply by elastically deforming the outer peripheral portion 18a, and the assemblability is improved and the central portion 18b of the sealing member 18 is thin. Since it is formed, it can be easily elastically deformed as if it were the bottom of a bead and can follow changes in bearing internal pressure.

  The sealing member 17 shown in (b) is joined by a liquid sealant 20 having elasticity, and the through hole 16 is closed. The liquid sealing agent 20 is also referred to as a liquid gasket. Specifically, the liquid sealing agent 20 is a non-drying paste having a modified ester resin as a main component, and can close the through-hole 16 without peeling (trade name; ThreeBond 1121). ). Moreover, since this liquid sealing agent also has adhesiveness, it can prevent that rainwater, dust, etc. penetrate | invade into the inside of a bearing through the through-hole 16 from the outside. The liquid sealant may be, for example, a phenol-based, acrylic-based, or silicon-based resin as a main component, in addition to the one having a modified ester resin as a main component.

  The protective cover 21 shown in (c) is formed into a cup shape by press working from a nonmagnetic austenitic stainless steel plate, and is fitted with a cylindrical fitting portion 10a that is press-fitted into the inner periphery of the end portion of the outer member 2. A disc-shaped shielding portion 10b extending radially inward from the fitting portion 10a, a bottom portion 21b for closing the inner side end of the inner member 1 from the shielding portion 10b via the cylindrical portion 21a, and the bottom portion 21b A recess 21c bulging from the outer side to the outer side is provided, and a through hole 16 is formed in the recess 21c. The sealing member 17 is joined so as to close the through hole 16 as in the above-described embodiment. Here, the depth of the concave portion 21c of the protective cover 21 is set so as not to protrude from the bottom portion 21b to the inner side in a state where the sealing member 17 is most swelled. Thereby, it can prevent that the sealing member 17 interferes with a peripheral component, and is damaged, and reliability improves.

  The sealing member 17 shown in (d) is joined to the bottom 10 d on the outer side of the protective cover 10. Thereby, since a junction part is not exposed outside, durability can be improved.

  The sealing member 22 shown in (e) is formed in a diaphragm shape having folds 22a made of concentric circles. Accordingly, it is possible to easily follow the change in the internal pressure of the bearing and suppress the pressure change, and it is possible to improve durability without applying an excessive force to the joint portion.

  FIGS. 5A and 5B show another modification of the sealing member 17 described above. The sealing member 23 shown in (a) is made of synthetic rubber such as NBR, and is press-fitted into the outer member 2 while being joined to the protective cover 10. In this case, after press-fitting the protective cover 10, a hollow needle 24, a so-called injection needle, is inserted into, for example, the central portion of the sealing member 23 to cancel (bleed out) the internal pressure that has increased due to the press-fitting. Thereafter, the needle 24 is removed and the hole is closed with an adhesive. Thereby, when the protective cover 10 is press-fitted into the outer member 2, it is possible to reliably prevent the internal pressure of the bearing from being increased by the air that is pushed in, and the elastic deformation of the sealing member 23 as in the above-described embodiment. Can absorb changes in the internal pressure of the bearing.

  The sealing member 25 shown in (b) is made of vinyl methyl silicone rubber (VMQ) having good gas permeability, and is press-fitted into the outer member 2 while being bonded to the protective cover 10. In this case, after press-fitting the protective cover 10, the hollow needle 24 is inserted into the navel portion 25 a formed at the center of the sealing member 25 to cancel the internal pressure raised by the press-fitting. In this embodiment, since the sealing member 25 is formed of VMQ, it is not necessary to pull out the needle 24 and close the hole with an adhesive, and the hole can be closed by the reaction force of the material itself. Thereby, the number of assembling steps can be further reduced as compared with the embodiment described above.

Next, a method for mounting the protective cover 10 will be described in detail with reference to FIG.
As shown to (a), the wheel bearing apparatus is set up vertically and it mounts so that the crimping part 7 may be located upwards. On the other hand, the protective cover 10 is held by the pushing jig 26. The pushing jig 26 is composed of a cylindrical guide ring 27 and a pushing part 28 that is fitted in the guide ring 27 so as to be able to advance and retreat, and has a recess 28 a that houses the protective cover 10. A plurality of communication holes 27a penetrating in the radial direction are formed in the guide ring 27 in the circumferential direction. The protective cover 10 is held in a state of being fitted and inserted into the inner periphery of the end of the guide ring 27.

  Here, an elastic body 29 having a convex spherical surface 29 a is joined to the recess 28 a of the pushing portion 28. The elastic body 29 is made of synthetic rubber such as NBR, and its elastic force is set to be smaller than the bearing internal pressure due to the press-fitting of the protective cover 10 and larger than the elastic force of the sealing member 17.

  And as shown in (b), the pushing jig | tool 26 is mounted in the end surface of the outer member 2, and the shielding part 10b of the protective cover 10 is pushed by the pushing part 28, and the edge part inner periphery of the outer member 2 is made. A protective cover 10 is attached. When the protective cover 10 is attached to the outer member 2, the air inside the bearing is compressed. However, since the sealing member 17 is deformed in advance by the convex spherical surface 29 a of the elastic body 29, the air in the bearing is correspondingly reduced. Is compressed and converted into a pressing force that deforms the sealing member 17 and restores it to the original straight shape, as indicated by the arrow. As a result, air can be prevented from being compressed inside the bearing as the protective cover 10 is pressed into the outer member 2, and the protective cover 10 can be positioned and fixed accurately and smoothly.

  FIG. 7 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. Note that this embodiment basically has no speed detection device and the configuration of the protective cover is different from that of the first embodiment (FIG. 1) described above. Parts are denoted by the same reference numerals and detailed description thereof is omitted.

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1, outer member 2, and both members 1,2. 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  A protective cover 30 attached to the inner side end of the outer member 2 is joined to a core bar 31 formed into a substantially L-shaped cross section by cold pressing from a cold-rolled steel sheet, and the core bar 31. And a cover body 32. The cover main body 32 is insert-molded into the cored bar 31 by injection molding with a thermoplastic synthetic resin such as PA (polyamide) 66 filled with 10 to 40 wt% of a fibrous reinforcing material such as GF (glass fiber). The cover main body 32 is formed in a cup shape, and includes a cylindrical fitting portion 32a having a thin end and a bottom portion 32b extending radially inward from the fitting portion 32a. A through hole 33 is formed at the center. The sealing member 17 made of synthetic rubber such as NBR is joined to the through-hole 33 to close the through-hole 33. In this embodiment, since the protective cover 30 is formed by injection molding from synthetic resin, not only can the weight be reduced, but also the airtightness of the fitting surface between the outer member 2 and the protective cover 30 can be improved. Can do.

  In addition to the above-mentioned PA66, the cover main body 32 may be made of a so-called engineering plastic such as PPA (polyphthalamide) and PBT (polybutylene terephthalate), polyphenylene sulfide (PPS), poly Thermoplastic synthetic resins called super engineering plastics such as ether ether ketone (PEEK) and polyamideimide (PAI), or heat such as phenol resin (PF), epoxy resin (EP), polyimide resin (PI) A curable synthetic resin may be used. Further, it may be a biodegradable synthetic resin that reduces the environmental load. Examples of the components of this biodegradable synthetic resin include polylactic acid, polycaprolactone, polyglycolic acid, modified polyvinyl alcohol, and casein. Moreover, as a fibrous reinforcement, not only GF but CF (carbon fiber), an aramid fiber, a boron fiber, etc. can be illustrated.

  FIG. 8 is a longitudinal sectional view showing a third embodiment of the wheel bearing device according to the present invention. Note that this embodiment basically differs from the second embodiment (FIG. 7) described above only in the configuration of the protective cover, and the same reference numerals are given to other parts and parts having the same parts or parts having the same functions. Detailed description will be omitted.

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 34, the outer member 2, and both members 34, 2. 3 and 3. The inner member 34 includes a hub ring 35 and an inner ring 36 that is press-fitted into the hub ring 35 via a predetermined scissors.

  The hub wheel 35 integrally has a plurality of circumferentially divided wheel mounting flanges 37 at the outer end on the outer periphery, and a hub bolt 6a for fastening a wheel (not shown) is planted on the outer periphery. It is installed. The wheel mounting flange 37 is formed so as to protrude radially from the annular base portion with a width substantially the same as the portion where each bolt insertion hole 38 is formed by cutting out a portion excluding the vicinity of the hub bolt insertion hole 38. That is, the wheel mounting flange 37 is divided into a plurality of partial flanges 37a that are separated in the circumferential direction.

  A support ring 39 having an L-shaped cross section is fitted on the inner ring 36. The support ring 39 includes a cylindrical portion 39a that is press-fitted into the outer diameter of the inner ring 36, and a standing plate portion 39b that extends radially inward from the cylindrical portion 39a, and is formed on the inner side surface of the standing plate portion 39b. The magnetic encoder 40 is integrally joined by vulcanization adhesion. In the magnetic encoder 40, magnetic powder such as ferrite is mixed in synthetic rubber, and magnetic poles N and S are magnetized alternately at equal pitches in the circumferential direction.

  The support ring 39 is formed by press working from a ferromagnetic steel plate, for example, a ferritic stainless steel plate or a rust-proof cold rolled steel plate. Thereby, the magnetic output of the magnetic encoder 40 becomes strong, and stable detection accuracy can be ensured.

  Even if the protective cover 41 attached to the inner side end of the outer member 2 is formed into a cup shape by pressing from a nonmagnetic austenitic stainless steel plate, it is cold rolled steel plate (JIS standard SPCC system, etc.) It may be formed into a cup shape by pressing and painted for rust prevention. The protective cover 41 has a cylindrical fitting portion 41a that is press-fitted into the inner periphery of the end of the outer member 2, and extends radially outward from the fitting portion 41a. And a bottom 41c extending inward in the radial direction from the flange 41b. A cylindrical fixing portion 43 to which the rotation speed sensor 42 is attached is provided on the bottom portion 41c. A rotational speed sensor 42 molded with synthetic resin is disposed opposite the magnetic encoder 40 with a predetermined air gap (axial clearance).

  A through hole 44 is formed in the bottom 41c of the protective cover 41, and the sealing member 17 made of synthetic rubber such as NBR is joined to the through hole 44 so that the through hole 44 is closed. In this embodiment, since the rotation speed sensor 42 is integrally fixed to the protective cover 41, the air gap adjustment can be simplified.

  FIG. 9 is a longitudinal sectional view showing a fourth embodiment of the wheel bearing device according to the present invention. The present embodiment is basically different from the third embodiment (FIG. 8) described above only in the configuration of the protective cover, and other parts and portions having the same parts or the same functions as the above-described embodiments. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1, outer member 2, and both members 1,2. 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The protective cover 45 is fitted and fixed to the inner end of the outer member 2 to close the opening of the outer member 2. The protective cover 45 includes a cored bar 31 and a cover body 46 joined to the cored bar 31. The cover main body 46 is insert-molded into the core metal 31 by injection molding with a thermoplastic synthetic resin such as PA66 filled with 10 to 40 wt% of a fibrous reinforcing material such as GF. The cover main body 46 is formed in a cup shape, and includes a cylindrical fitting portion 32a having a thin end portion and a bottom portion 46a extending radially inward from the fitting portion 32a. A through hole 33 is formed. The sealing member 17 made of synthetic rubber such as NBR is joined to the through-hole 33 to close the through-hole 33.

  Here, a mounting portion 47 projecting in the axial direction is integrally provided on the radially outer portion of the cover main body 46, and an insertion hole 47a penetrating in the axial direction at a position corresponding to the magnetic encoder 40 of the mounting portion 47. Is formed. The rotational speed sensor 15 is inserted into the insertion hole 47a via an O-ring.

  A nut 48 having an internal thread 48a formed on the inner periphery is embedded in the mounting portion 47 of the cover body 46 by insert molding, and the rotation speed sensor 15 is fixed to the mounting portion 47 via a fixing bolt (not shown). And the sealing member 49 is mounted | worn with the communicating hole of the side surface of the nut 48, and the communicating hole is sealed. Thus, even if foreign matter such as muddy water enters from a minute screw gap formed between the female thread 48a of the nut 48 and the screw engaging portion of the fixing bolt, the sealing member 49 prevents foreign matter from entering the bearing. can do. The seal member 49 is made of an elastic material such as NBR, chloroprene rubber (CR), or fluororubber (FKM).

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a caulking type wheel bearing device on the driven wheel side of the 2.5th generation and 3rd generation structures.

DESCRIPTION OF SYMBOLS 1, 34 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 2c Inner side end surface 3 of outer member Rolling elements 4, 35 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step 5, 36 Inner ring 6, 37 Wheel mounting flange 6a Hub bolt 6b Base portion 7 on the inner side of the wheel mounting flange 7 Clamping portion 8 Cage 9 Seals 10, 21, 30, 41, 45 on the outer side Protective covers 10a, 32a, 41a Fitting portion 10b Shielding portion 10c Bending portion 10d, 21b, 32b, 41c, 46a Bottom portion 11, 31 Core metal 12, 49 Seal member 12a Side lip 12b Dustrip 12c Grease lip 13, 39 Support ring 13a, 39a Cylindrical portion 13b, 39b Standing plate portion 14, 40 Magnetic encoder 15, 42 Rotational speed sensor 16, 33, 44 Through hole 17, 18, 22, 23, 25 Ring member 18a Outer peripheral part 18b Central part 19 Annular recess 20 Liquid sealant 21a Cylindrical part 21c Recess 22a Hollow 24 Hollow needle 25a Navel part 26 Pushing jig 27 Guide ring 27a Communication hole 28 Pushing part 28a Recess 29 Elastic body 29a Convex Spherical surface 32, 46 Cover main body 37a Partial flange 38 Hub bolt insertion hole 41b Fence part 43 Fixing part 47 Mounting part 47a Insertion hole 48 Nut 48a Female thread 50, 68, 73 Outer member 50a Outer rolling surface 50b Car body mounting flange 51 Inner member 52 Ball 53 Hub wheel 53a, 54a Inner rolling surface 53b Small diameter step portion 53c Caulking portion 54 Inner ring 55 Wheel mounting flange 55a Base 56 Seal ring 57 Encoder 58 Support ring 59 Encoder body 60, 65, 70 Cover 61 Outer cylindrical portion 62 Annular flat portion 63 bottom surface portion 64 sensor 6 Cover body 67, 71 the bent portions 67a, 69a conical portion 67b, inside 69b the cylindrical portion 69, 74 peripheral surface 72 protrusion 75 recess groove K annular space

Claims (12)

An outer member integrally having a vehicle body mounting flange for being attached to a knuckle constituting a suspension device on the outer periphery, and an outer rolling surface of a double row integrally formed on the inner periphery;
From a hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a small-diameter step extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step of the hub ring An inner member in which a double row inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery,
A double row rolling element housed in a freely rolling manner between the rolling surfaces of the inner member and the outer member;
An annular space is formed by the outer member and the inner member having a seal attached to the outer end portion of the outer member and a protective cover attached to the inner end portion of the outer member. In the wheel bearing device in which the opening of
The protective cover is formed in a cup shape including a cylindrical fitting portion that is press-fitted into an inner periphery of an end portion of the outer member, and a bottom portion that closes an inner side end portion of the inner member, and the bottom portion A through hole is formed, and a sealing member made of synthetic rubber is joined to the through hole to close the through hole, and the elastic force of the sealing member is set to be smaller than the elastic force of the seal. A wheel bearing device.   The protective cover is formed of a non-magnetic material, and a rotational speed sensor is brought close to or in contact with the protective cover, and a magnetic encoder is fitted on the inner ring, and the magnetic encoder and the rotational speed sensor cover the protective cover. The wheel bearing device according to claim 1, wherein the wheel bearing device is arranged to face each other with a predetermined air gap therebetween.   The wheel bearing device according to claim 1 or 2, wherein the protective cover is formed by pressing from an austenitic stainless steel plate.   The wheel bearing device according to claim 1 or 2, wherein the protective cover is formed from a thermoplastic synthetic resin by injection molding.   The protective cover includes a concave portion that bulges to the outer side at the bottom thereof, and the through hole is formed in the concave portion, and the depth of the concave portion is increased from the bottom portion to the inner portion with the sealing member being swelled most The wheel bearing device according to any one of claims 1 to 4, wherein the wheel bearing device is set so as not to protrude to the side.   The wheel bearing device according to any one of claims 1 to 5, wherein the sealing member is joined by a liquid sealant having elasticity.   The sealing member is formed with an annular recess in the outer peripheral portion thereof, the central portion is formed thinner than the outer peripheral portion, and the annular recess is fitted into the through hole of the protective cover, thereby The wheel bearing device according to any one of claims 1 to 5, wherein the sealing member is integrally joined.   The wheel bearing device according to any one of claims 1 to 5, wherein the sealing member is joined to a bottom portion on the outer side of the protective cover.   The wheel bearing device according to any one of claims 1 to 8, wherein the sealing member is formed in a diaphragm shape having a concentric fold.   The wheel bearing device according to any one of claims 1 to 9, wherein a temperature TR10 at which the sealing member exhibits a low temperature elastic recovery rate of 10% is set to -35 ° C or lower.   The wheel bearing device according to any one of claims 1 to 10, wherein a surface protective agent made of wax or an anti-aging agent is applied to the sealing member.   The wheel bearing device according to any one of claims 1 to 11, wherein the sealing member is formed of vinyl methyl silicone rubber.

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