JP5914077B2 - Wheel bearing device - Google Patents

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. 8 is known as an example of such a wheel bearing device. This wheel bearing device is supported and fixed to a knuckle (not shown), an outer member 51 serving as a fixing member having a double row outer raceway surface 51a formed on the inner periphery, and a double row ball on the outer member 51. A hub ring 53 inserted through 52 and an inner ring 54 fitted on the hub ring 53 are included.

  One inner rolling surface (not shown) is integrally formed on the outer periphery of the hub wheel 53, and the other inner rolling surface 54 a is formed on the outer periphery of the inner ring 54. The inner ring 54 is press-fitted into a shaft-shaped small diameter step portion 53 a extending in the axial direction from the inner rolling surface of the hub ring 53. The double-row balls 52 are respectively accommodated between these rolling surfaces and are held by a cage 55 so as to be freely rollable.

  The hub wheel 53 is integrally provided with a wheel mounting flange for mounting a wheel (not shown) on the outer periphery, and a crimped portion 56 is formed by plastically deforming an end portion of the small-diameter stepped portion 53a radially outward. The inner ring 54 is fixed in the axial direction by a fastening portion 56. A cover 57 is attached to the end of the outer member 51 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater, dust, or the like into the bearing from the outside.

  The cover 57 is made of a nonmagnetic metal plate such as SUS304, an austenitic stainless steel plate, an aluminum alloy, or a synthetic resin plate, and includes a bottom plate portion 58 and an outer peripheral edge of the bottom plate portion 58. And a cylindrical portion 59 bent at a right angle inward in the axial direction. In addition, an outward flange-like butting portion 60 is provided in a state of being bent at a right angle outward from the axial inner end edge of the cylindrical portion 59, and is in contact with the end face of the outer member 51.

  The bottom plate portion 58 has a flat plate portion 58 a and a bulging portion 58 b, and the flat plate portion 58 a is provided near the outer peripheral edge of the bottom plate portion 58. Further, the bulging portion 58b is provided at a central portion of the bottom plate portion 58 and is provided at a portion that is radially inward from the flat plate portion 58a, and bulges inward in the axial direction from the flat plate portion 58a. Further, the outer peripheral surface of the inner end portion of the cylindrical portion 59 is covered with a sealing material 61 having elasticity such as an elastomer such as rubber over the entire circumference.

  Such a cover 57 is supported and fixed to the outer member 51 by fixing the cylindrical portion 59 to the inner end portion in the axial direction of the outer member 51 with an interference fit. The axially outer surface of the abutting portion 60 is abutted against the inner end surface of the outer member 51 over the entire circumference, and the axially outer surface of the flat plate portion 58a is pressed into the outer periphery of the inner ring 54. It faces the detection surface of the encoder 62 in close proximity via a minute gap.

  In addition, a sensor holding plate 64 for supporting the sensor 63 is fitted and fixed to the inner end of the outer member 51 in the axial direction by an interference fit. The sensor holding plate 64 is made of a ferrous metal such as carbon steel or stainless steel, a non-ferrous metal such as an aluminum alloy, or a synthetic resin, and is configured in a petri dish as a whole. The bottom plate portion 65 has a circular flat plate shape, and a fitting tube portion 66 bent at a right angle from the outer peripheral edge of the bottom plate portion 65 in the axially outward direction. A through hole 67 is formed in a portion near the outer diameter of the bottom plate portion 65, and a mounting hole 68 is formed in a portion closer to the center than the through hole 67, and a mounting hole 68 is formed on a part of the outer surface of the bottom plate portion 65. A nut 69 is fixed to a portion surrounding the outer periphery by welding, bonding, press-fitting, caulking, or the like.

  In such a sensor holding plate 64, the fitting cylinder portion 66 is fitted on the inner end portion in the axial direction of the outer member 51, and the cover 57 abuts between the bottom plate portion 65 and the end surface of the outer member 51. The part 60 is clamped from both sides in the axial direction. Accordingly, the cover 57 is prevented from being displaced inward in the axial direction, and the cover 57 is covered from the inner side in the axial direction through the space 70.

  The sensor 63 is attached and fixed to the sensor holding plate 64 by bolts 71 and nuts 69. In order to fix the sensor 63 to the sensor holding plate 64, the front end portion of the magnetic encoder 62 is inserted into the space 70 through the through hole 67 formed in the sensor holding plate 64, and the flat plate portion constituting the bottom plate portion 58. While abutting against the axially inner side surface of 58a and the mounting flange 72 abutting against the axially inner side surface of the nut 69, an insertion hole formed with the mounting flange 72 and a mounting hole 68 formed in the sensor holding plate 64. The bolt 71 inserted through the insertion hole from the inside in the axial direction is screwed into the nut 69 and further tightened.

  In this way, the cover 57 that closes the opening of the internal space 73 in which the magnetic encoder 62 is installed can be prevented from being pushed into the magnetic encoder 62 side due to the pressing of the detection portion of the sensor 63 and the like. Axial displacement can be regulated with high accuracy. Further, it is possible to prevent the cover 57 from being deformed so as to reduce the detection accuracy of the sensor 63.

  Further, when the cylindrical portion 59 constituting the cover 57 is fitted into the end portion of the outer member 51, a force directed radially inward is applied to the bottom plate portion 58, but consumed to deform the bulging portion 58b. Is done. As a result, the deformation amount of the flat plate portion 58a can be sufficiently suppressed, and the axial position of the flat plate portion 58a can be regulated with high accuracy (see, for example, Patent Document 1).

JP 2010-180912 A

  In such a conventional wheel bearing device, among the cover 57 and the sensor holding plate 64 attached to the end of the outer member 51, the cover 57 attached to the inside is press-fitted into the inner peripheral surface of the end, The sensor holding plate 64 attached to the outside is press-fitted into the outer peripheral surface of the end portion. In this case, since the sensor holding plate 64 is an external fitting type, when the fitting member 66 is press-fitted into the outer member 51, the opening of the fitting cylinder portion 66 expands in a trumpet shape, and the fixing force is weakened. Otherwise, it may come out when deformation occurs due to a large load. Further, the rigidity of the sensor holding plate 64 is lowered as compared with the internal fitting type, and the strength and rigidity for supporting the sensor 63 are lowered, so that stable detection accuracy may not be maintained.

  The present invention has been made in view of the above-described conventional problems, and provides a wheel bearing device in which detection accuracy and sealing performance are improved and the rigidity of a sensor cap is increased to improve reliability. For the purpose.

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. A moving body, a pulsar ring that is externally fitted to the inner ring, and whose characteristics are alternately changed at equal intervals in the circumferential direction, and an inner end of the outer member are fitted to the radially outer part. comprising a steel plate or we form made cup-shaped sensor cap the rotational speed sensor is mounted, the rotary In a wheel bearing device in which a degree sensor is opposed to the pulsar ring via a predetermined axial air gap, a cup-shaped inner cap is press-fitted to the inner periphery of the inner side end of the outer member via a predetermined squeeze. the inner cap is made of austenitic stainless steel or et forms of non-magnetic, a cylindrical fitting portion which is press-fitted in the peripheral edge portion of the inner side of the outer member, the radially inward from the fitting portion The pulsar ring is provided with a disk part facing the pulsar ring via a slight axial clearance, and the rotational speed sensor is abutted or brought close to the disk part, and is disposed opposite the pulsar ring via the inner cap. Rutotomoni, the sensor cap is press via a predetermined Interference in the peripheral edge portion of the outer member of the inner side of the inner cap, the bottom of the sensor cap Closer to the road surface radially outward, is bulged portion protrudes by a predetermined dimension in the inner side from the bottom forming, drain penetrating in the expanded portion in the radial direction is formed.

In this way, it is externally fitted to the inner ring, fitted with the pulsar ring whose characteristics are alternately changed at equal intervals in the circumferential direction, and the inner side end of the outer member, and rotated to the radially outer part. comprising a steel plate or we form made cup-shaped sensor cap speed sensor is mounted, the rotational speed sensor in a wheel bearing apparatus which is opposed via a predetermined axial air gap pulser ring, the outer member inner side end in the cup-shaped inner cap in a circumferential is press via a predetermined Interference, the inner cap is made of austenitic stainless steel or et forms of non-magnetic, press-fit within the peripheral edge portion of the inner side of the outer member A cylindrical fitting portion that extends radially inward from the fitting portion and faces the pulsar ring through a slight axial clearance, and a rotational speed sensor is provided on the disc portion. Or near Is, while being opposed to the pulser ring via the inner cap, the outer end portion in the sensor cap circumference of the member of the inner side of the inner cap is pressed over a predetermined Interference, radial direction of the bottom portion of the sensor cap On the side close to the outer road surface, a bulge is formed by projecting a predetermined dimension from the bottom to the inner side, and a drain penetrating in the radial direction is formed in the bulge, so that detection accuracy and sealing It is possible to provide a wheel bearing device that improves the reliability and improves the reliability of the sensor cap by increasing the rigidity of the sensor cap. In addition, if the knuckle protrudes from the end face of the outer member to the inner side, even if foreign matter such as rainwater enters from the outside into the sensor cap, it will flow and fall into this bulging part and be disturbed by the knuckle. The foreign matter can be effectively discharged to the outside easily.

  Preferably, as in the invention described in claim 2, an inner fitting surface is formed on the inner periphery of the end portion of the outer member, and an outer fitting surface is formed on the inner side of the inner fitting surface via a step. If the sensor cap is press-fitted into the outer fitting surface and the inner cap is press-fitted into the inner fitting surface, the press-in stroke of the inner cap is minimized and the assembly workability is improved. The deformation of the inner cap in the press-fitting process can be prevented, and the reliability of the product can be improved.

Further, as in the third aspect of the invention, if the inner fitting surface and the outer fitting surface are ground surfaces, it is possible to simultaneously grind the double row outer rolling surfaces with a general-purpose grindstone. In addition, the accuracy of roundness and coaxiality of each fitting surface is improved, the airtightness of the fitting portion is increased, and the number of processing steps can be reduced by simultaneous grinding, so that the cost can be reduced. .

  According to a fourth aspect of the present invention, the sensor cap includes a cylindrical fitting portion that is press-fitted into the inner periphery of the inner side end of the outer member, and a radially outward direction from the fitting portion. And a bottom portion that closes the opening on the inner side of the outer member from the flange, and extends to the inner side end surface of the outer member. If a fitting insertion hole is formed in the corresponding horizontal position and the rotation speed sensor is mounted in this fitting insertion hole, the rigidity can be increased and the positioning accuracy of the rotation speed sensor can be improved, and the horizontal position from the wheel can be increased. Even in a state in which the outer member and the inner member are relatively inclined due to the directional load, fluctuations in the air gap between the rotation speed sensor and the pulsar ring can be suppressed, and stable detection accuracy can be obtained.

  If the depth of the outer fitting surface is set to be deeper than the thickness of the sensor cap as in the invention described in claim 5, the fitting portion of the sensor cap is an outer member. It can prevent that the foreign material which protruded from the inner periphery of this edge part and infiltrated in the sensor cap stagnates in this part.

  Further, as in the invention described in claim 6, if a rust preventive film made of cationic electrodeposition coating is formed on the sensor cap, the rust preventive film is not easily peeled off when pressed into the outer member. It is possible to maintain a smooth surface by filling minute concavities and convexities on the fitting surface, and to prevent the fitting portion of the sensor cap from rusting over a long period of time. Good airtightness can be obtained.

According to a seventh aspect of the present invention, a reduced diameter portion is formed between the fitting portion of the inner cap and the disc portion, and an elastic member made of synthetic rubber is vulcanized and bonded to the reduced diameter portion. And the elastic member protrudes from the side surface of the disk portion of the inner cap to the inner side so as not to interfere with the rotational speed sensor, and is radially outer than the outer diameter of the fitting portion. If the annular protrusion protruding in the direction is provided, the annular protrusion is elastically deformed and pressure-bonded to the inner periphery of the end portion of the outer member when the inner cap is fitted, so that the airtightness of the fitting portion can be improved.

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 in which an inner rolling surface is formed, a double-row rolling element housed in a freely rolling manner between the respective rolling surfaces of the outer member and the inner member, and an outer fit to the inner ring, alternately characteristics in the circumferential direction, and a pulser ring that is changed at regular intervals, the outer is fitted to an end portion of the inner side of the member, steel sheet or al the rotational speed sensor is mounted radially outward portion comprising a shape made cup-shaped sensor cap, the rotational speed sensor is said pulser ring In a wheel bearing device that faces a predetermined axial air gap, a cup-shaped inner cap is press-fitted through a predetermined shimiro to the inner periphery of the inner side end of the outer member. made of austenitic stainless steel or al the form of magnetic, a cylindrical fitting portion which is press-fitted in the peripheral edge portion of the inner side of the outer member extends from the fitting portion radially inwardly, the pulsar ring A disk portion facing each other through a slight axial clearance, and the rotational speed sensor is abutted or brought close to the disk portion, and is disposed opposite to the pulsar ring via the inner cap; the inner side the outer the sensor cap to the peripheral edge portion of the member is press via a predetermined Interference, closer to the road surface radially outward of the bottom portion of the sensor cap The bottom bulging portion protrudes by a predetermined size is formed on the inner side from, since the drain penetrating the bulging portion in the radial direction is formed, together with improved sealing performance and detection accuracy, sensor cap It is possible to provide a wheel bearing device in which the rigidity of the wheel is increased to improve the reliability. In addition, if the knuckle protrudes from the end face of the outer member to the inner side, even if foreign matter such as rainwater enters from the outside into the sensor cap, it will flow and fall into this bulging part and be disturbed by the knuckle. The foreign matter can be effectively discharged to the outside easily.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a principal part enlarged view which shows the detection part of FIG. It is a perspective view which shows the outer side cap of FIG. (A) is a longitudinal cross-sectional view which shows the inner cap single-piece | unit of FIG. 1, (b) is a longitudinal cross-sectional view which shows the outer cap single-piece | unit of FIG. It is a principal part enlarged view which shows the drain part of FIG. (A) is a principal part enlarged view which shows the fitting part of the outer side cap of FIG. 1, (b) is a principal part enlarged view which shows the modification of (a). It is explanatory drawing which shows the grinding method of the outer member of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows the conventional wheel bearing apparatus.

  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. Double-row rolling elements housed in a freely rollable manner between the surfaces, a magnetic encoder fitted to the inner ring, and an inner end of the outer member, which are fitted to the outer end and rotated radially outward. Cup-shaped sensor cap formed by pressing from a steel plate to which a speed sensor is attached A wheel-type bearing device in which the rotational speed sensor is opposed to the pulsar ring via a predetermined axial air gap, and a cup-shaped inner cap is provided on the inner periphery of the inner side end of the outer member. The inner cap is formed by press working from a non-magnetic austenitic stainless steel plate and is press-fitted into the inner periphery of the inner side end of the outer member, and the fitting portion A disk part extending inward in the radial direction and facing the magnetic encoder through a slight axial clearance, and extending inward in the radial direction from the disk part via a bent part, and the inner part of the inner member Provided with a bottom portion that covers an end portion on the side, the rotational speed sensor is abutted or brought close to the disc portion, and is disposed to face the magnetic encoder via the inner cap, Mating surface fitted via a step into the end periphery of the outer member of the inner side of the side caps are formed, the sensor cap is press fitted through a predetermined Interference on the fitting surface.

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. 2 is an enlarged view of a main part showing a detection unit of FIG. 1, and FIG. 3 is a perspective view showing an outer cap of FIG. 4 (a) is a longitudinal sectional view showing the inner cap alone of FIG. 1, FIG. 4 (b) is a longitudinal sectional view showing the outer cap alone of FIG. 1, and FIG. 5 is a main portion showing the drain portion of FIG. 6 (a) is an enlarged view of a main part showing a fitting part of the outer cap of FIG. 1, (b) is an enlarged view of a main part showing a modification of (a), and FIG. It is explanatory drawing which shows the grinding method of a member. 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 called the third generation on the driven wheel side, and is a double row rolling element (ball) accommodated between the inner member 1 and the outer member 2 and between the members 1 and 2 so as to roll freely. 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. Hub bolts 6a are planted on the wheel mounting flange 6 at equal intervals 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 an inner cap 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.

  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. 2, 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 adhesion or the like. ing. 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, as shown in FIG. 1, an inner cap 15 is attached to the outer member 2 to close the opening on the inner side of the outer member 2. The inner cap 15 has a corrosion resistance and is formed into a cup shape by pressing 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. ), 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 slight shaft is attached to the magnetic encoder 14 from the fitting portion 15a via the reduced diameter portion 15b. A bottom portion 15e that covers an inner side end portion of an inner member (not shown) via a circular plate portion 15c facing each other through a directional gap and a bent portion 15d bulging outward from the circular plate portion 15c. I have.

  As shown in an enlarged view in FIG. 2, the inner cap 15 is integrally joined to the reduced diameter portion 15b by an elastic member 18 made of synthetic rubber such as NBR by vulcanization adhesion. The elastic member 18 protrudes inward from the side surface of the disk portion 15c of the inner cap 15 so as not to interfere with the rotational speed sensor 21, and is an annular shape protruding radially outward from the outer diameter of the fitting portion 15a. A protrusion 18a is provided. The inner fitting surface 19 on the inner periphery of the end of the outer member 2 is restricted to a chatter height of 3 μm or less, and the inner projection surface 19 of the outer member 2 is fitted to the annular protrusion 18a when the inner cap 15 is fitted. It is elastically deformed and pressure-bonded to form a half metal structure to enhance the airtightness of the fitting portion 15a.

  In the present embodiment, an outer cap (sensor cap) 16 is further attached to the inner side of the inner cap 15. Specifically, an outer fitting surface 20 formed of an annular groove is formed on the opening side (inner side) of the inner fitting surface 19 of the outer member 2 via a predetermined step 19a, and the outer cap 16 is disposed outside the outer cap 16. The fitting surface 20 is press-fitted through a predetermined scissors.

  The outer cap 16 is formed into a cup shape by press working from a rust-proof cold-rolled steel plate, and is press-fitted into the inner periphery of the inner end of the outer member 2 as shown in FIGS. 3 and 4B. A cylindrical fitting portion 16a, a flange portion 16b that overlaps and extends radially outward from the fitting portion 16a, and is in close contact with the inner end face 2d of the outer member 2, and the flange portion 16b. A bottom portion 16c that closes the opening on the inner side of the outer member 2. A fitting hole 17 is formed in a horizontal position corresponding to the magnetic encoder 14 in the bottom portion 16 c of the outer cap 16, and a rotational speed sensor 21 described later is fitted into the fitting hole 17. Thus, since the outer 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 can be improved, and the insertion hole 17 can be provided. If it is formed in a horizontal position and the rotation speed sensor 21 is mounted in the fitting insertion hole 17, it can rotate 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 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 outer 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 outer 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 outer 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 inner side of the bottom portion 16c of the outer cap 16, the fixing nut 23 is drawn into the inner surface of the bottom portion 16c by fastening the mounting bolt 25. Dropping off can be prevented only by simply tightening 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 abuts on or approaches the disc portion 15c of the inner cap 15 (see FIG. 2). 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 at the inside of the bearing by the inner cap 15 in which the elastic member 18 made of synthetic rubber is provided in the reduced diameter portion 15b. Can be reliably sealed, and a wheel bearing device with improved sealing performance can be provided.

  A rust preventive film is formed on the outer cap 16 by cationic electrodeposition coating. 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 outer cap 16 is a powerful 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.

  Thus, in this embodiment, since the rust preventive film which consists of cationic electrodeposition coating is formed in the outer cap 16, and the zinc phosphate process is performed as a ground treatment of cationic electrodeposition coating, adhesion of a coating material is carried out. The rust preventive film is not easily peeled off during press-fitting into the outer member 2 and can maintain a smooth surface by filling minute concavities and convexities on the fitting surface 16a. Rusting over a long period of time can be prevented, and good airtightness can be obtained between the outer fitting surface 20 and the end surface 2d of the outer member 2.

  The plate thickness t1 of the inner cap 15 described above is set to be thinner than the plate thickness t2 of the outer cap 16. Specifically, the plate thickness t2 of the inner cap 15 is set to 0.2 to 1.0 mm while the plate thickness t2 of the outer cap 16 is set to 1.0 to 1.5 mm. 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 inner cap 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, as shown in FIGS. 3 and 4B, the drain 26 is formed on the radially outer side of the bottom 16 c of the outer 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. 5, 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 outer cap 16 in the radial direction, even if foreign matter such as rainwater enters the outer cap 16 from the outside, it flows into the bulging portion 27 portion. The foreign matter can easily and effectively be discharged outside without being blocked by the knuckle 9.

  Furthermore, in the present embodiment, as shown in an enlarged view in FIG. 6A, the depth of the outer fitting surface 20 of the outer member 2 is set to be deeper than the plate thickness of the outer cap 16. . This is because the fitting portion 16a protrudes from the inner periphery of the end portion of the outer member 2 and smoothly flows to the bulging portion 27 and is discharged from the drain 26 so that the foreign matter entering the outer cap 16 does not stay in this portion. This is because it can.

  In addition, as shown in (b), if the end inner peripheral surface 28 of the outer member 2 is formed into a tapered surface having an inclination angle α that gradually expands toward the end surface 2d, the foreign matter that has entered the outer cap 16 can be obtained. Can be guided to the bulging portion 27 more smoothly.

  Next, a method for grinding the outer member 2 will be described with reference to FIG. In the turning process, the outer member 2 includes a double row outer rolling surfaces 2a and 2a, an inner fitting surface 19 into which an inner cap (not shown) is press-fitted to an inner end, and the inner fitting. An outer fitting surface 20 into which the outer cap 16 is press-fitted through a predetermined step 19 a is formed on the inner side of the mating surface 19. Then, after the heat treatment step by induction hardening, in the grinding step, the double-row outer rolling surfaces 2a and 2a, and the inner fitting surface 19 and the outer fitting surface 20 are simultaneously ground by the overall grindstone 29.

  Grinding is performed in a state in which the centering shoe 30 is slidably contacted with the outer peripheral surface 2f on the inner side of the outer member 2 and the backing plate 31 is abutted against the outer end surface 2e of the outer member 2. The general-purpose grindstone 29 is rotated in a fixed direction so as to have a desired shape and size. In addition, the general-purpose grindstone 29 is formed in a desired shape and size in advance by a rotary dresser (not shown), and is positioned on the outer member 2 while being fixed to the quill 32.

  In the present embodiment, the inner fitting surface 19 and the outer fitting surface 20 are ground together with the double-row outer rolling surfaces 2a, 2a by the overall grindstone 29. The accuracy of the circularity and the coaxiality is improved, the airtightness of the fitting portion is increased, the number of processing steps can be reduced by simultaneous grinding, and the cost can be reduced. Further, when the inner cap 15 and the outer cap 16 are press-fitted into the mere mating surfaces, not only the press-fitting stroke of the inner cap 15 is increased and the assembling workability is lowered, but the thin inner cap 15 is deformed in the press-fitting process. There is a fear. In this embodiment, since the outer fitting surface 20 is formed on the inner side of the inner fitting surface 19 via the step 19a, the press-fit stroke of the inner cap 15 is minimized and the assembly workability is improved. The deformation of the inner cap 15 in the press-fitting process can be prevented, and the reliability of the product can be improved.

  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 an inner ring rotating type wheel bearing device of any structure such as a driven wheel and a rolling element of a ball, a tapered roller or the like.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 2c Pilot part 2d Outer member inner side end surface 2e Outer member outer side end surface 2f Outer member inner side end outer peripheral surface DESCRIPTION OF SYMBOLS 3 Rolling body 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 part of the inner side of a wheel mounting flange 7 Cage 8 Seal 9 Knuckle 10 Core metal 11 Seal Member 11a Side lip 11b Dustrip 11c Grease lip 12 Pulsar ring 13 Support ring 13a Cylindrical portion 13b Standing plate portion 14 Magnetic encoder 15 Inner cap 15a, 16a Fitting portion 15b Reduced diameter portion 15c Disc portion 15d Bending portion 15e Bottom portion 16 Outer cap 16b collar 16c bottom 17 fitting insertion hole 18 elastic member 18a annular projection 19 inside fitting Surface 19a Step 20 Outer fitting surface 21 Rotational speed sensor 22 Perforation 23 Fixing nut 24 Mounting member 25 Mounting bolt 26 Drain 27 Expanded portion 28 End member inner peripheral surface 29 Total grinding wheel 30 Shoe 31 Backing plate 32 Quill 51 Outer member 51a Outer rolling surface 52 Ball 53 Hub wheel 53a Small diameter step portion 54 Inner ring 54a Inner rolling surface 55 Cage 56 Clamping portion 57 Cover 58 Bottom plate portion 58a Flat plate portion 58b Swelling portion 59 Cylindrical portion 60 Butting portion 61 Seal material 62 Magnetic encoder 63 Sensor 64 Sensor holding plate 65 Bottom plate portion 66 Fitting cylinder portion 67 Through hole 68 Mounting hole 69 Nut 70 Space 71 Bolt 72 Mounting flange 73 Internal space L Projection amount t1 from bottom of bulging portion Cap thickness t2 Outer cap thickness α Inclination angle of the inner peripheral surface of the end

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;
Pulsar ring that is externally fitted to the inner ring, and the characteristics are changed alternately and at equal intervals in the circumferential direction;
With the outer is fitted to an end portion of the inner side of the member, the steel plate or et shape made cup-shaped sensor cap rotational speed sensor in the radially outward portion is attached,
In the wheel bearing device in which the rotational speed sensor is opposed to the pulsar ring via a predetermined axial air gap,
Said outer inner side of the end portion in the cup-shaped inner cap in a circumferential member is press via a predetermined Interference, the inner cap is made of austenitic stainless steel or et forms of non-magnetic, the inner of the outer member A cylindrical fitting portion that is press-fitted into the inner periphery of the end portion, and a disk portion that extends radially inward from the fitting portion and faces the pulsar ring via a slight axial clearance;
The rotational speed sensor is abutted or approached to the disc part, and is disposed opposite to the pulsar ring via the inner cap,
Wherein said outer said sensor cap inner periphery end of the member of the inner side of the inner cap is pressed over a predetermined Interference, side closer to the road surface radially outward of the bottom portion of the sensor cap, inner from the bottom A wheel bearing device, characterized in that a bulging portion is formed by projecting to the side by a predetermined dimension, and a drain penetrating in the radial direction is formed in the bulging portion .   An inner fitting surface is formed on the inner periphery of the end of the outer member, an outer fitting surface is formed on the inner side of the inner fitting surface via a step, and the sensor cap is press-fitted into the outer fitting surface. The wheel bearing device according to claim 1, wherein an inner cap is press-fitted into the inner fitting surface. The wheel bearing device according to claim 2, wherein the inner fitting surface and the outer fitting surface are ground surfaces .   A cylindrical fitting portion that is press-fitted into the inner periphery of the inner side end of the outer member, and the sensor cap overlaps and extends radially outward from the fitting portion, and the inner side of the outer member. And a bottom portion that closes the opening on the inner side of the outer member from the flange portion, and a fitting insertion hole is formed at a horizontal position corresponding to the pulsar ring on the bottom portion. The wheel bearing device according to claim 1, wherein the rotation speed sensor is mounted in the insertion hole.   The wheel bearing device according to claim 2 or 3, wherein a depth of the outer fitting surface is set to be deeper than a plate thickness of the sensor cap.   The wheel bearing device according to claim 1, wherein a rust preventive film made of cationic electrodeposition coating is formed on the sensor cap.   A reduced diameter portion is formed between the fitting portion of the inner cap and the disk portion, and an elastic member made of synthetic rubber is integrally joined to the reduced diameter portion by vulcanization adhesion. 2. An annular protrusion that protrudes inward from the side surface of the disk portion of the inner cap so as not to interfere with the rotational speed sensor, and that protrudes radially outward from the outer diameter of the fitting portion. The wheel bearing apparatus described in 1.

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