JP2015068454A - Wheel bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing device improved in sealing performance by enhancing the air tightness of a protection cover.SOLUTION: An end internal periphery of an outer member 2 comprises an inside fitting face 19a into which a protection cover 30 is pressure-inserted, and a large-diameter seal fitting face 19c via a step part 19b. The protection cover 30 comprises: a cylindrical fitting part 15a into which the inside fitting face 19a is pressure-inserted; a cylindrical joining part 15c which extends to an axial direction via a stepped part 15b hanging down to the inside of a radial direction, and is coaxial with the seal fitting face 19c; and a disc-shaped block part 15d which extends to the inside of the radial direction, and opposes pulser ring 12 via a minute axial clearance. In the protection cover, an elastic member 31 made of synthetic rubber is integrally joined to the stepped part 15b and the joining part 15c. The protection cover also comprises an annular protrusion 18a protruding to the outside of a radial direction rather than an outside diameter of the fitting part 15a, and an annular protrusion 29a protruding to the outside of the radial direction at an inner side of the annular protrusion, and having a lip shape inclined to the inner side at its tip. The protection cover is pressure-joined to the seal fitting face 19c.

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like with respect to a suspension device, and more particularly to a wheel bearing device to which a rotation speed sensor for detecting the rotation speed of a wheel is attached.

  In general, a wheel bearing device in which a wheel of an automobile is rotatably supported with respect to a suspension device and an anti-lock brake system (ABS) is controlled to detect a rotation speed of the wheel is incorporated. Are 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. In addition, the rotational speed detecting device is constituted by a magnetic encoder and a rotational speed sensor that is arranged facing the magnetic encoder and detects a magnetic pole change of the magnetic encoder accompanying the rotation of the wheel.

  In general, the rotational speed sensor is attached to the knuckle after the wheel bearing device is attached to the knuckle constituting the suspension device. However, in order to eliminate the complexity of adjusting the air gap between the rotational speed sensor and the magnetic encoder and to make it more compact, a wheel bearing device to which a rotational speed sensor is also attached has recently been proposed. .

  A structure as shown in FIG. 8A is known as an example of such a wheel bearing device. The wheel bearing device is inserted into the outer member 51 via a double row ball 52 and an outer member 51 as a fixing member having a double row outer raceway 51a formed on the inner periphery. A hub ring (not shown) and an inner ring 53 that is press-fitted and fixed to a small-diameter step portion of the hub ring and has an inner raceway surface 53a formed on the outer periphery. And the inner ring | wheel 53 is fixed to the axial direction by the crimping part 54 formed by carrying out the plastic deformation of the edge part of the small diameter step part of a hub ring radially outward.

  A support ring 56 having an L-shaped cross section in which a magnetic encoder 55 is joined to the inner ring 53 is externally fitted, and a protective cover 57 is attached to the opening of the outer member 51 to leak the lubricating grease enclosed in the bearing. This prevents rainwater and dust from entering the bearing from the outside.

  The protective cover 57 attached to the end of the outer member 51 is formed into a ring shape by press working from a non-magnetic austenitic stainless steel plate, and is a cylindrical fitting that is press-fitted into the inner periphery of the end of the outer member 51. The joint portion 57a, the disc-shaped shielding portion 57c extending radially inward from the fitting portion 57a through the reduced diameter portion 57b, and the outer member 51 from the shielding portion 57c through the stepped portion 57d. And a bottom 57e that closes the opening. The detecting portion 58a of the rotational speed sensor 58 fixed to the knuckle K is brought close to or in contact with the shielding portion 57c of the protective cover 57, and the detecting portion 58a and the magnetic encoder 55 are connected to a predetermined air through the protective cover 57. Opposed to each other with a gap.

  The reduced diameter portion 57b of the protective cover 57 has a stepped shape, and a seal member 59 is fixed to the outer peripheral portion thereof. The seal member 59 is made of synthetic rubber, and is integrally joined to the protective cover 57 by vulcanization adhesion, and includes a convex portion 59a and an annular portion 59b. The annular portion 59b is formed to be slightly smaller in diameter than the outer diameter of the fitting portion 57a, and the convex portion 59a is formed to be slightly larger in diameter than the outer diameter of the fitting portion 57a. It is press-fitted into the peripheral surface 51b. Thereby, the airtightness of the fitting surface of the outer member 51 and the protective cover 57 can be improved over a long period of time (see, for example, Patent Document 1).

JP 2012-189096 A

  In such a conventional wheel bearing device, since the seal device is not installed in the opening of the annular space formed between the outer member 51 and the inner ring 53, the inside of the bearing is sealed only by the protective cover 57. This prevents leakage of the lubricated grease and prevents rainwater and dust from entering the bearing from the outside. However, this type of wheel bearing device is used under severe environmental conditions that are subject to muddy water, etc., and in recent years, the tightness of the mating surface has been further increased in order to satisfy strict specification requirements from users. A protective cover 57 is required.

  In particular, in the conventional structure, the reduced diameter portion 57b of the protective cover 57 to which the sealing member 59 made of synthetic rubber is joined has a stepped shape, and as shown in FIG. 8B, a cylindrical portion that is straight in the axial direction. However, when the protective cover 57 is press-fitted into the inner peripheral surface 51b of the end portion 51 of the outer member 51, the sealing member 59 receives the reaction force from the outer member 51 in the axial direction. A component force that causes displacement occurs, and the seal member 59 escapes in the direction of the arrow, so that a sufficient surface pressure cannot be secured, and the surface pressure changes due to the settling of the seal member 59 due to deterioration over time. Then there was a problem I said.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a wheel bearing device in which the airtightness of a protective cover is improved to improve the sealing performance.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel for attaching a wheel to one end. A hub ring integrally having a mounting flange and formed with a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring. An inner member in which a double row of inner rolling surfaces facing the outer rolling surface is formed, and a double row of rolling members housed between the outer member and the inner member so as to roll freely. In a wheel bearing device comprising a moving body and a cup-shaped protective cover press-fitted into an inner peripheral end of the outer member, the inner peripheral end of the outer member is pressed into the protective cover. An inner fitting surface, and a cylindrical shape formed from the inner fitting surface through a stepped portion. A cylindrical fitting portion that is press-fitted into the inner fitting surface of the outer member, and a stepped portion that hangs radially inward from the fitting portion. And a concentric cylindrical joint extending in the axial direction and parallel to the seal fitting surface, and a disk-shaped shield extending radially inward from the joint, and the step of the protective cover An elastic member made of synthetic rubber is integrally joined to the attachment portion and the joint portion, and this elastic member protrudes radially outward from the outer diameter of the fitting portion, and has an annular protrusion that is crimped to the seal fitting surface. I have.

  Thus, in the wheel bearing device including the cup-shaped protective cover press-fitted into the inner periphery of the outer member on the inner side, the inner periphery of the outer member is fitted into the inner periphery where the protective cover is press-fitted. A cylindrical seal fitting surface having a large diameter from the inner fitting surface through a step portion, and a protective cover is press-fitted into the inner fitting surface of the outer member. A concentric cylindrical joint extending in the axial direction through a stepped portion that hangs radially inward from the fitting portion and the fitting portion, and a concentric cylindrical joint parallel to the seal fitting surface, and a radial direction from the joint An elastic member made of synthetic rubber is integrally joined to the stepped portion and the joint portion of the protective cover, and the elastic member is radially connected to the outer diameter of the fitting portion. Since it has an annular projection that protrudes outward and is crimped to the seal fitting surface, the protective cover is attached to the outer member. When press-fitting, not only does the elastic member escape to the inner side and the surface pressure decreases, but also the elastic member can be prevented from becoming loose due to deterioration over time, thereby preventing the surface pressure from changing. Thus, it is possible to provide a wheel bearing device in which the hermeticity of the protective cover is increased to improve the sealing performance.

  In addition, as in the invention described in claim 2, a pulsar ring whose characteristics are alternately changed in the circumferential direction is externally fitted to the inner ring, and the protective cover is formed of a non-magnetic steel plate. If the rotational speed sensor is opposed to the pulsar ring with an axial air gap via a cover, the air gap can be set small, and the detection accuracy can be increased.

  If the tip of the annular protrusion of the elastic member is formed in a lip shape inclined toward the inner side as in the invention described in claim 3, the outer member is deformed into an elliptical shape by a load applied to the outer member. In this case, stable airtightness can be provided.

  According to a fourth aspect of the present invention, the elastic member includes an annular protrusion that protrudes radially outward from the outer diameter of the fitting portion of the protective cover, and a radially outer portion on the inner side of the annular protrusion. If the ring-shaped protrusions project in the direction and have a lip shape with the tip inclined toward the inner side, these annular protrusions are elastically deformed to the seal fitting surface of the outer member when the protective cover is fitted. The hermeticity of the protective cover can be further enhanced by the synergistic effect of the two annular protrusions of the elastic member that are crimped.

  Further, as in the invention according to claim 5, if the outer peripheral surface of the annular projection of the elastic member is formed on a tapered surface that gradually increases in diameter toward the inner side, the shimeshi can be set large, The airtightness of the protective cover can be further increased.

  Further, as in the invention described in claim 6, a cylindrical outer fitting surface is formed on the inner side of the seal fitting surface of the outer member, and a cup shape is further formed on the inner side of the protective cover. The sensor cap is attached to the cylindrical fitting portion that is press-fitted into the outer fitting surface, and extends and overlaps radially outward from the fitting portion. And a bottom portion that closes the opening on the inner side of the outer member from the collar portion, and a fitting insertion hole is formed at a horizontal position corresponding to the pulsar ring on the bottom portion, If the rotational speed sensor is mounted in this insertion hole, not only the sealing inside the bearing is improved by the double cap, but also the rigidity of the sensor cap is increased to improve the positioning accuracy of the rotational speed sensor. If you can Even in a state where the outer member and the inner member are relatively inclined due to the lateral load from the wheel, the fluctuation of the air gap between the rotational speed sensor and the pulsar ring can be suppressed, and stable detection accuracy can be obtained. it can.

  Further, as in the invention described in claim 7, if the inner fitting surface and the seal fitting surface of the outer member are simultaneously processed by cutting, the roundness, the coaxiality, etc. of each fitting surface This improves the accuracy, increases the air tightness of the fitting portion, reduces the number of processing steps by simultaneous cutting, and can reduce the cost.

  The wheel bearing device according to the present invention integrally has an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and on the outer periphery. A hub wheel formed with a small-diameter step portion extending in the axial direction, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring, and a double row of the double row facing the outer rolling surface of the double row on the outer periphery. An inner member on which an inner rolling surface is formed, a double row rolling element that is movably accommodated between the rolling surfaces of the outer member and the inner member, and an inner side of the outer member A cup-shaped protective cover that is press-fitted into the inner periphery of the end of the outer member, wherein the inner periphery of the outer member has an inner fitting surface into which the protective cover is press-fitted, and the inner fitting. A cylindrical seal fitting surface formed in a large diameter from a mating surface through a step portion, and the protection The bar extends in the axial direction through a cylindrical fitting portion press-fitted into the inner fitting surface of the outer member, and a stepped portion that hangs radially inward from the fitting portion, and the seal fitting A concentric cylindrical joint parallel to the mating surface and a disk-shaped shield extending radially inward from the joint, and the stepped portion and the joint of the protective cover are made of synthetic rubber. An elastic member is integrally joined, and this elastic member has an annular protrusion that protrudes radially outward from the outer diameter of the fitting portion and is crimped to the seal fitting surface. When press-fitting into a member, not only prevents the elastic member from escaping to the inner side and lowering the surface pressure, but also prevents the elastic member from being set up due to deterioration over time to prevent the surface pressure from changing. The bearing assembly for the wheel that can improve the airtightness of the protective cover and improve the sealing performance It is possible to provide a.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. (A) is a principal part enlarged view which shows the fitting part of the protective cover of FIG. 1, (b) is the A section enlarged view of (a). (A) is a longitudinal cross-sectional view which shows the protective cover single-piece | unit of FIG. 1, (b) is a longitudinal cross-sectional view which shows the sensor cap single-piece | unit of FIG. It is a principal part enlarged view which shows the drain part of the sensor cap of FIG. (A) is a principal part enlarged view which shows the modification of the protective cover of FIG. 2, (b) is the B section enlarged view of (a). (A) is a principal part enlarged view which shows the modification of the protective cover of FIG. 5, (b) is the C section enlarged view of (a). (A) is a principal part enlarged view which shows the modification of the protective cover of FIG. 6, (b) is the D section enlarged view of (a). (A) is a principal part enlarged view which shows the conventional wheel bearing apparatus, (b) is the E section enlarged view of (a).

  An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel integrally formed and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member formed of an inner ring press-fitted into a small-diameter step portion and formed with an inner rolling surface facing the other of the double row outer rolling surfaces, and the rolling of each of the outer member and the inner member. Made of a double-row rolling element accommodated in a freely rolling manner between the surfaces, a magnetic encoder fitted to the inner ring, and a cup-shaped non-magnetic material press-fitted to the inner periphery of the inner side end of the outer member And a rotation speed sensor through the protective cover. In the wheel bearing device opposed to the axial air gap, the inner periphery of the end portion of the outer member has an inner fitting surface into which the protective cover is press-fitted, and a step portion from the inner fitting surface. A cylindrical seal fitting surface having a large diameter is provided, and the protective cover is press-fitted into the inner fitting surface of the outer member. A concentric cylindrical joint that extends in the axial direction through a stepped portion that hangs in the direction parallel to the seal fitting surface, and extends radially inward from the joint to the pulsar ring. And an elastic member made of synthetic rubber is integrally joined to the stepped portion and the joint portion of the protective cover, and the elastic member is a fitting portion of the protective cover. An annular protrusion protruding radially outward from the outer diameter of the Projecting radially outwards over the side, an annular projection forming a lip shape tip is inclined inner side, these annular projections are crimped to the sealing mating faces.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2A is an enlarged view of a main part showing a fitting portion of the protective cover of FIG. 1, and FIG. 3A is an enlarged view of part A, FIG. 3A is a longitudinal sectional view showing the protective cover alone in FIG. 1, FIG. 3B is a longitudinal sectional view showing the sensor cap alone in FIG. 1, and FIG. FIG. 5A is an enlarged view of a main part showing a modification of the protective cover of FIG. 2, and FIG. 5B is an enlarged view of a B part of FIG. 6A is an enlarged view of a main part showing a modified example of the protective cover of FIG. 5, FIG. 6B is an enlarged view of a C part of FIG. 7A, and FIG. 7A is a modified version of the protective cover of FIG. The principal part enlarged view which shows an example, (b) is the D section enlarged view of (a). 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).

  The wheel bearing device shown in FIG. 1 is referred to as the third generation on the driven wheel side, and is a double row rolling element that is accommodated so as to roll freely between the inner member 1 and the outer member 2, and both members 1 and 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 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 has one (outer side) inner rolling surface 4a on the outer periphery and the inner rolling surface. A small diameter step 4b extending in the axial direction from the surface 4a is formed. In addition, hub bolts 6a are planted on the wheel mounting flange 6 in the circumferential direction.

  The inner ring 5 is formed with the other (inner side) inner raceway surface 5a on the outer periphery and is press-fitted into the small-diameter stepped portion 4b of the hub wheel 4 to form a back-to-back type double row angular contact ball bearing. The inner ring 5 is fixed in the axial direction by a caulking portion 4c formed by plastically deforming the end portion of 4b. Thereby, weight reduction and size reduction can be achieved. The inner ring 5 and the rolling elements 3 and 3 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

  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 includes an inner rolling surface 4a and an inner side of a wheel mounting flange 6 serving as a seal land portion of a seal 8 described later. The surface hardness is hardened to a range of 58 to 64 HRC by induction hardening from the base 6b to the small diameter step 4b. Note that the caulking portion 4c is left with a raw surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, the fretting resistance of the small-diameter step portion 4b serving as the fitting portion of the inner ring 5 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 4c can be performed smoothly.

  The outer member 2 integrally has a vehicle body mounting flange 2b to be attached to the knuckle 9 on the outer periphery, and a cylindrical pilot portion 2c fitted to the knuckle 9 is formed on the inner side of the vehicle body mounting flange 2b. The outer outer rolling surface 2a facing the inner rolling surface 4a of the hub wheel 4 and the inner outer rolling surface 2a facing the inner rolling surface 5a of the inner ring 5 are integrally formed on the inner periphery. ing. Double-row rolling elements 3 and 3 are accommodated between these rolling surfaces and are held by the cages 7 and 7 so as to be freely rollable. A seal 8 is attached to the opening on the outer side of the annular space formed between the outer member 2 and the inner member 1, and a protective cover 15 described later is attached to the opening on the inner side. This prevents the grease sealed inside the bearing from leaking to the outside and prevents rainwater and dust from entering the bearing from the outside.

  The outer member 2 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least the double row outer rolling surfaces 2a and 2a have a surface hardness of 58 to 64 HRC by induction hardening. Has been cured.

  The seal 8 is constituted by an integral seal composed of a cored bar 10 press-fitted into the inner periphery of the outer end of the outer member 2 and a seal member 11 integrally joined to the cored bar 10 by vulcanization adhesion. ing. The metal core 10 has a substantially L-shaped cross section by press working from an austenitic stainless steel plate (JIS standard SUS304 type or the like) or a cold rolled steel plate (JIS standard SPCC type or the like). On the other hand, the seal member 11 is made of a synthetic rubber such as NBR (acrylonitrile-butadiene rubber) and has a side lip 11a, a dust lip 11b, and a grease lip 11c that are in sliding contact with the outer peripheral surface of the base portion 6b. And the sealing member 11 wraps around and joins so that the outer surface of the metal core 10 may be covered, and what is called a half metal structure is comprised. Thereby, airtightness can be improved and the inside of a bearing can be protected.

  In addition to the exemplified NBR, the material of the seal member 11 includes, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc. having 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.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling elements 3 and 3 was illustrated here, it is not restricted to this but is comprised by the double row tapered roller bearing using a tapered roller It may be what was done. Moreover, although the wheel bearing device called the third generation in which the inner raceway surface 4a is directly formed on the outer periphery of the hub wheel 4 is illustrated, the wheel bearing device according to the present invention is not limited to such a structure, For example, although not shown, a first generation or second generation structure in which a pair of inner rings are press-fitted into a small diameter step portion of the hub ring may be used.

  In the present embodiment, the pulsar ring 12 is press-fitted into the outer periphery of the inner ring 5. As shown in an enlarged view in FIG. 2A, the pulsar ring 12 includes a support ring 13 formed in an annular shape, and a magnetic encoder 14 integrally joined to the side surface of the support ring 13 by vulcanization bonding or the like. It consists of This magnetic encoder 14 is a rotary encoder for detecting the rotational speed of a wheel by mixing magnetic powder such as ferrite in an elastomer such as rubber and magnetizing magnetic poles N and S alternately in the circumferential direction.

  The support ring 13 is formed into a substantially L-shaped cross section by pressing from a ferromagnetic steel plate, for example, a ferritic stainless steel plate (JIS standard SUS430 series or the like) or a rust-proof cold-rolled steel plate. And a standing plate portion 13b extending radially outward from the cylindrical portion 13a. The magnetic encoder 14 is joined to the inner side surface of the upright plate portion 13b.

  Here, the protective cover 15 attached to the outer member 2 has corrosion resistance and is pressed from a non-magnetic austenitic stainless steel plate so as not to adversely affect the sensing performance of the rotational speed sensor 21 described later. It is formed in a cup shape. As shown in FIG. 3A, a cylindrical fitting portion 15a that is press-fitted into the inner periphery of the inner side end of the outer member 2, and a step that hangs radially inward from the fitting portion 15a. A cylindrical joint 15c extending in the axial direction via the attached portion 15b, and a disk-shaped shield extending radially inward from the joint 15c and facing the magnetic encoder 14 through a slight axial clearance 15d and a bottom portion 15f that covers an inner side end of an inner member (not shown) via a bent portion 15e that bulges outward from the shielding portion 15d.

  In the protective cover 15, an elastic member (seal member) 18 made of synthetic rubber such as NBR is integrally joined to the stepped portion 15b and the joining portion 15c by vulcanization adhesion. The elastic member 18 protrudes from the side surface of the shielding portion 15d of the protective cover 15 to the inner side so as not to interfere with the rotational speed sensor 21, and is fitted as shown in an enlarged view in FIG. An annular protrusion 18a is provided that protrudes radially outward from the outer diameter of the portion 15a. The inner periphery of the end portion of the outer member 2 has a large diameter through an inner fitting surface 19a into which the fitting portion 15a of the protective cover 15 is press-fitted and a tapered step portion 19b from the inner fitting surface 19a. A cylindrical seal fitting surface 19c is formed. When the protective cover 15 is fitted, the annular protrusion 18a of the elastic member 18 is elastically deformed and pressure-bonded to the seal fitting surface 19c, thereby forming a half metal structure and improving the airtightness of the fitting portion 15a.

  Further, since the seal fitting surface 19c is formed with a larger diameter than the inner fitting surface 19a into which the fitting portion 15a of the protective cover 15 is press-fitted, the fitting portion 15a is press-fitted when the protective cover 15 is fitted. Therefore, even if scratches or chips are generated on the inner fitting surface 19a, the seal fitting surface 19c to which the elastic member 18 is crimped is not damaged, so that airtightness can be improved.

  Furthermore, in this embodiment, the elastic member 18 is formed in a substantially square cross section, and the joint 15c of the protective cover 15 is concentric cylindrical (straight) parallel to the seal fitting surface 19c of the outer member 2. Therefore, when the protective cover 15 is press-fitted into the outer member 2, the elastic member 18 receives the reaction force from the outer member 2 at the straight portion of the joint 15c, and the elastic member 18 is displaced in the axial direction. No moving force is generated. Therefore, it is possible to prevent the elastic member 18 from escaping to the inner side and reducing the surface pressure, and also to prevent the elastic member 18 from being set up due to deterioration over time, thereby preventing the surface pressure from changing. It is possible to provide a wheel bearing device in which the airtightness of the cover 15 is increased to improve the sealing performance.

  In the present embodiment, a sensor cap 16 is further attached to the inner side of the protective cover 15. Specifically, as shown in FIG. 2A, a cylindrical outer fitting surface 20 is formed on the opening side (inner side) of the seal fitting surface 19c of the outer member 2, and the sensor cap 16 is The outer fitting surface 20 is press-fitted through a predetermined squeeze. At least the outer fitting surface 20, the inner fitting surface 19a, and the seal fitting surface 19c are simultaneously processed by a cutting process such as a grinding process or a turning process. Preferably, after the heat treatment step by induction hardening, in the grinding step, simultaneous grinding is performed by the double row outer rolling surfaces 2a and 2a and the overall grindstone.

  Thus, if the outer fitting surface 20, the inner fitting surface 19a, and the seal fitting surface 19c are processed at the same time, the accuracy of the roundness, the coaxiality, etc. of each fitting surface 19a, 19c, 20 is improved. As a result, the airtightness of the fitting portion is increased, and the number of processing steps can be reduced by simultaneous cutting, and the cost can be reduced. In addition, since the seal fitting surface 19c and the outer fitting surface 20 are formed on the inner side of the inner fitting surface 19a via the step portion 19b, the press-fit stroke of the protective cover 15 is minimized and the assembly workability is improved. And the deformation of the protective cover 15 in the press-fitting process can be prevented, and the reliability of the product can be improved.

  The sensor cap 16 is formed into a cup shape by press working from a rust-proof cold-rolled steel plate, and is cylindrically inserted into the outer fitting surface 20 of the outer member 2 as shown in FIG. A fitting portion 16a, a flange portion 16b that overlaps and extends radially outward from the fitting portion 16a, and comes into close contact with the inner side end surface 2d of the outer member 2, and the flange portion 16b to the outer member 2 And a bottom portion 16c for closing the opening on the inner side. An insertion hole 17 is formed in a horizontal position corresponding to the magnetic encoder 14 in the bottom portion 16 c of the sensor cap 16, and a rotational speed sensor 21 described later is inserted into the insertion hole 17. Thus, since the sensor cap 16 includes the flange portion 16b that is in close contact with the end surface 2d of the outer member 2, the rigidity can be increased and the positioning accuracy of the rotational speed sensor 21 can be improved, and the insertion hole 17 can be improved. Is formed in a horizontal position, and if the rotational speed sensor 21 is mounted in the fitting insertion hole 17, even when the outer member 2 and the inner member 1 are relatively inclined due to a lateral load from the wheel, The fluctuation of the air gap between the rotation speed sensor 21 and the magnetic encoder 14 can be suppressed, and stable detection accuracy can be obtained.

  A fixing nut 23 is fixed to the perforation 22 formed on the center side of the sensor cap 16 by caulking. The fixing nut 23 is caulked and fixed to the bearing inner side (outer side) of the bottom portion 16 c of the sensor cap 16. In addition to this, the fixing nut 23 may be fixed by, for example, welding, adhesion, press-fitting, or the like. The rotational speed sensor 21 inserted into the insertion hole 17 of the sensor cap 16 is fixed by fastening the mounting bolt 25 to the fixing nut 23 via the mounting member 24. Thus, in this embodiment, since the fixing nut 23 is fixed to the bearing inward side of the bottom portion 16c of the sensor cap 16, the fixing nut 23 is drawn into the inner surface of the bottom portion 16c by fastening the mounting bolt 25. Dropping can be prevented only by simple caulking and fixing of the fixing nut 23.

  The rotation speed sensor 21 is an IC incorporating a magnetic detection element such as a Hall element, a magnetoresistive element (MR element) or the like that changes characteristics according to the flow direction of magnetic flux and a waveform shaping circuit that adjusts the output waveform of the magnetic detection element. The anti-lock brake system of the motor vehicle which consists of these etc. and detects the rotational speed of a wheel and controls the rotation speed is comprised. And this rotational speed sensor 21 is inserted until it contacts or closes to the shielding part 15d of the protective cover 15 (see FIG. 2A). As a result, a desired air gap can be obtained, and it is possible to improve the assembly workability by omitting complicated air gap adjustment, and the inside of the bearing is protected by the protective cover 15 provided with the elastic member 18 made of synthetic rubber at the joint 15c. Can be sealed.

  A rust preventive film (not shown) is formed on the sensor cap 16 by cationic electrodeposition coating. Here, a rust preventive film is formed on the entire surface of the sensor cap 16. Here, in order to reduce the cost, a rust preventive film may be formed only on the contact portion between the outer fitting surface 20 of the outer member 2 and the end surface 2d on the inner side. The cationic electrodeposition coating is an anionic electrodeposition coating in which the product side is energized with the product side as the negative electrode while the positive electrode is energized with the product side as the positive electrode. Also good. This anion-type electrodeposition coating has the characteristics that the coating color stability and baking temperature can be set low, but this type of sensor cap 16 has a strong coating with excellent rust prevention and adhesion. Cationic electrodeposition coating made of an epoxy resin system or the like that can form a film is preferred.

  In the present embodiment, zinc phosphate treatment is applied as a base treatment (pretreatment) for cationic electrodeposition coating. Since the surface of the steel material as a raw material is roughened by a chemical reaction by this zinc phosphate treatment, the bite of the paint is improved and the adhesion is improved. Further, a sealer treatment may be performed after the zinc phosphate treatment. This sealer is a kind of metal surface treatment agent, for example, a so-called chemical conversion treatment in which a chemical conversion film can be formed by performing immersion for a short time of about 30 seconds to 2 minutes, or spray treatment. Excellent film adhesion can be secured, and a protective film of the material can be formed, and a strong rust prevention function and conductivity can be exhibited. In other words, the zinc phosphate treatment is applied as a base treatment for the cationic electrodeposition coating, and the sealer treatment is performed thereon to smooth the fine surface of the zinc phosphate coating, thereby causing the air during paint electrodeposition. Can be prevented. If air is involved, surface defects such as craters (uneven surfaces such as irregularities) may occur in the coating film, which is not preferable.

  As described above, in this embodiment, a rust preventive film made of cationic electrodeposition coating is formed on the contact portion of the sensor cap 16 with the outer member 2, and zinc phosphate treatment is used as a base treatment for the cationic electrodeposition coating. As the coating is applied, the adhesion of the paint is improved, and the rust preventive film is not easily peeled off when being pressed into the outer member 2, and the smooth surface can be maintained by filling in the minute irregularities of the fitting surface. At the same time, the fitting portion 16a of the sensor cap 16 can be prevented from rusting over a long period of time, and good airtightness can be obtained between the outer fitting surface 20 and the end surface 2d of the outer member 2. It is done.

  The plate thickness t1 of the protective cover 15 described above is set to be thinner than the plate thickness t2 of the sensor cap 16. Specifically, the plate thickness t1 of the protective cover 15 is set to 0.2 to 1.0 mm with respect to the plate thickness t2 of the sensor cap 16. As a result, the air gap can be set small, and the detection accuracy can be increased. Further, the weight can be reduced, and the workability can be improved to reduce the cost. If the plate thickness t1 is less than 0.2 mm, it is difficult to accurately shape the shape of the protective cover 15, and if it exceeds 1.0 mm, the air gap becomes large and desired magnetic characteristics can be obtained. This cannot be done and the detection accuracy is reduced.

  In the present embodiment, the drain 26 is formed on the radially outer side of the bottom portion 16 c of the sensor cap 16. The drain 26 is formed in the bulging portion 27 on the side close to the road surface of the fitting portion 16a and the bottom portion 16c. The bulging portion 27 is formed to protrude from the bottom portion 16c to the inner side by a predetermined dimension L. As shown in an enlarged view in FIG. 4, the bulging portion 27 is effective when the knuckle 9 is not flush with the end surface 2 d of the outer member 2 but protrudes toward the inner side. That is, by forming the drain 26 through the bulging portion 27 of the sensor cap 16 in the radial direction, even if foreign matter such as rainwater enters the sensor cap 16 from the outside, it flows into the bulging portion 27 portion. As shown by arrows, the foreign matter can be easily and effectively discharged to the outside without being interrupted by the knuckle 9.

  FIG. 5A shows a modification of the protective cover 15 described above. The protective cover 28 basically has the same configuration of the metal part as that described above, except that the shape of the elastic member 18 is different. Therefore, the same reference numerals are given and redundant description is omitted. In the protective cap 28, an elastic member 29 made of synthetic rubber such as NBR is integrally joined to the stepped portion 15b and the joining portion 15c by vulcanization adhesion. As shown in FIG. 5B, the elastic member 29 includes an annular protrusion 29a that protrudes radially outward from the outer diameter of the fitting portion 15a and that has a tip end inclined toward the inner side. The annular protrusion 29a is elastically deformed and crimped to the seal fitting surface 19c of the outer member 2 when the protective cover 28 is fitted.

  In this embodiment, since the annular protrusion 29a of the elastic member 29 is formed in a lip shape, it can follow when the outer member 2 is deformed into an elliptical shape by a load applied thereto, and has stable airtightness. Can be provided.

  FIG. 6A shows a modified example of the protective cover 28 described above. The protective cover 30 basically has the same configuration of the metal portion as that described above except that the shape of the elastic member 29 is different. In the protective cap 30, an elastic member 31 made of synthetic rubber such as NBR is integrally joined to the stepped portion 15b and the joining portion 15c by vulcanization adhesion. As shown in FIG. 6B, the elastic member 31 includes an annular protrusion 18a that protrudes radially outward from the outer diameter of the fitting portion 15a, and an radially outer side on the inner side of the annular protrusion 18a. It has an annular protrusion 29a that protrudes and has a lip shape whose tip is inclined toward the inner side. These annular protrusions 28a and 29a are elastically deformed and pressure-bonded to the seal fitting surface 19c of the outer member 2 when the protective cover 30 is fitted. With this configuration, the airtightness of the protective cover 30 can be further enhanced by the synergistic effect of the two annular protrusions 18a and 29a of the elastic member 31.

  FIG. 7A shows a modified example of the protective cover 30 described above. The protective cover 32 basically has the same configuration of the metal part as that described above, except that the shape of the elastic member 31 is different. In the protective cap 32, an elastic member 33 made of synthetic rubber such as NBR is integrally joined to the stepped portion 15b and the joint portion 15c by vulcanization adhesion. As shown in FIG. 7 (b), the elastic member 33 protrudes radially outward from the outer diameter of the fitting portion 15a, and has an annular shape formed on a tapered surface whose outer peripheral surface gradually increases in diameter toward the inner side. A protrusion 33a is provided. The annular protrusion 33a is elastically deformed and pressure-bonded to the seal fitting surface 19c of the outer member 2 when the protective cover 32 is fitted.

  In the present embodiment, the annular protrusion 33a of the elastic member 33 is formed in a shape in which the annular protrusion 18a and the lip-shaped annular protrusion 29a are integrated, and the shimeshiro is set large. Airtightness can be further enhanced.

  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 is for a driven wheel and can be applied to an inner ring rotating type wheel bearing device having a first to third generation structure.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 2c Pilot part 2d Inner side end surface 3 of outer member Rolling element 4 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 4c Clamping part 5 Inner ring 6 Wheel mounting flange 6a Hub bolt 6b Base 7 on the inner side of the wheel mounting flange Cage 8 Seal 9 Knuckle 10 Core 11 Seal member 11a Side lip 11b Dustrip 11c Grease lip 12 Pulsar ring 13 Support ring 13a Cylindrical part 13b Standing plate Part 14 magnetic encoder 15, 28, 30, 32 protective cover 15a, 16a fitting part 15b stepped part 15c joint part 15d shielding part 15e bent part 15f, 16c bottom part 16 sensor cap 16b flange part 17 insertion holes 18, 29, 31, 33 Elastic members 18a, 29a, 33a Annular projection 19a Inner fitting 19b Stepped portion 19c Seal fitting surface 20 Outer fitting surface 21 Rotational speed sensor 22 Perforation 23 Fixing nut 24 Mounting member 25 Mounting bolt 26 Drain 27 Swelling portion 51 Outer member 51a Outer rolling surface 51b End inner peripheral surface 52 Ball 53 Inner ring 53a Inner rolling surface 54 Clamping portion 55 Magnetic encoder 56 Support ring 57 Protective cover 57a Fitting portion 57b Reduced diameter portion 57c Shielding portion 57d Stepped portion 57e Bottom portion 58 Rotational speed sensor 58a Detection portion 59 Seal member 59a Convex portion 59b Annular part K Knuckle L Projection amount from bottom of bulge

Claims (7)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion 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 accommodated in a freely rolling manner between the rolling surfaces of the outer member and the inner member;
In the wheel bearing device, comprising: a cup-shaped protective cover press-fitted into the inner periphery of the inner side end of the outer member;
The inner periphery of the end portion of the outer member includes an inner fitting surface into which the protective cover is press-fitted, and a cylindrical seal fitting surface formed from the inner fitting surface through a stepped portion,
The protective cover extends in the axial direction through a cylindrical fitting portion that is press-fitted into the inner fitting surface of the outer member, and a stepped portion that hangs radially inward from the fitting portion, A concentric cylindrical joint parallel to the seal fitting surface and a disk-shaped shielding part extending radially inward from the joint,
An elastic member made of synthetic rubber is integrally joined to the stepped portion and the joint portion of the protective cover, and this elastic member protrudes radially outward from the outer diameter of the fitting portion and is crimped to the seal fitting surface. A wheel bearing device characterized by comprising an annular projection.   A pulsar ring whose characteristics are alternately changed in the circumferential direction is externally fitted to the inner ring, and the protective cover is formed of a non-magnetic steel plate, and the rotational speed sensor is attached to the pulsar ring via the protective cover. The wheel bearing device according to claim 1, wherein the wheel bearing device is confronted by a directional air gap.   The wheel bearing device according to claim 1, wherein a tip end portion of the annular protrusion of the elastic member is formed in a lip shape inclined toward the inner side.   The elastic member protrudes radially outward from the outer diameter of the fitting portion of the protective cover, and a lip that protrudes radially outward on the inner side of the annular protrusion, with the tip inclined toward the inner side. The wheel bearing device according to claim 1, further comprising an annular protrusion having a shape.   The wheel bearing device according to claim 1, wherein an outer peripheral surface of the annular protrusion of the elastic member is formed as a tapered surface that gradually increases in diameter toward the inner side.   A cylindrical outer fitting surface is formed on the inner side of the seal fitting surface of the outer member, and a cup-shaped sensor cap is further mounted on the inner side of the protective cover. A cylindrical fitting portion that is press-fitted into the outer fitting surface, a flange that overlaps and extends radially outward from the fitting portion, and is in close contact with the inner end surface of the outer member, and the flange And a bottom portion that closes the opening on the inner side of the outer member, and a fitting insertion hole is formed at a horizontal position corresponding to the pulsar ring on the bottom portion, and the rotational speed sensor is attached to the fitting insertion hole. The wheel bearing device according to claim 1.   The wheel bearing device according to claim 1, wherein an inner fitting surface and a seal fitting surface of the outer member are processed simultaneously by cutting.

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