JP2009156399A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel installed to a knuckle by a stable fitting force even in a rise of a temperature, and stably performing revolution speed detection or the like. <P>SOLUTION: The bearing device for the wheel comprises: inner rings 24A, 24B having rolling faces 28, 29 on outer diameter surfaces; an outer ring 25 having rolling faces 26, 27 on an inner diameter face; rolling elements 30 housed rollingly between an outer rolling faces 26, 27 of the outer ring 25 and inner rolling faces 28, 29 of the inner rings 24A, 24B. In the bearing device for a wheel, at least the outer ring 25 is molded by cold rolling, and an annular recess 51 is formed at the axially center of the outer diameter face 50 of the outer ring 25. A resin band 17 formed of heat-resistant synthetic resin is filled in the annular recess 51 of the outer ring 25. A sensor unit is disposed at the resin band 17. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel with respect to a vehicle body in a vehicle such as an automobile.

  The wheel bearing device has evolved from a structure in which a double row rolling bearing called a first generation is used alone to a second generation in which a vehicle body mounting flange is integrated with an outer member. The third generation in which the inner raceway is integrally formed on one of the double row rolling bearings on the outer periphery of the hub wheel having an integral, and the constant velocity universal joint is integrated with the hub wheel. A fourth generation type has been developed in which the other inner rolling surface of the double row rolling bearing is integrally formed on the outer periphery of the outer joint member constituting the joint.

  In the first-generation wheel bearing device, it is necessary to press-fit into a knuckle on the vehicle body side, and man-hours are required for assembly and replacement. However, since the first-generation wheel bearing device can be manufactured at a lower cost than the second-generation or third-generation wheel bearing device, it is often used mainly for light vehicles and small vehicles.

  As shown in FIG. 10, a wheel bearing device called the first generation (for example, Patent Document 1) includes a hub wheel 102 having a flange 101 extending in the outer diameter direction, and an outer joint member 103 fixed to the hub wheel 102. The constant velocity universal joint 104 and the bearing 100 disposed on the outer peripheral side of the hub wheel 102 are provided.

  The constant velocity universal joint 104 includes the outer joint member 103, an inner joint member (not shown) disposed on the outer joint member 103, and a ball disposed between the inner joint member and the outer joint member 103. (Not shown) and a cage (not shown) for holding the ball. The outer joint member 103 includes a bowl-shaped mouth portion 107 in which the inner joint member is accommodated, and a shaft portion (stem portion) 123 protruding from the mouth portion 107.

  The hub wheel 102 includes a cylindrical portion 113 and the flange 101. A large-diameter first portion 115a and a small-diameter second portion 115b are provided on the outer end surface 114 (end surface on the anti-joint side) of the flange 101. The brake rotor 140 is externally fitted to the first part 115a, and a wheel (not shown) is externally fitted to the second part 115b.

  As shown in FIG. 11, the bearing 100 is formed with an outer ring 105 having double row outer rolling surfaces 120, 121 formed on the inner periphery and inner rolling surfaces 118, 119 facing the outer rolling surfaces on the outer periphery. Double row rolling elements 122 accommodated in a freely rollable manner between the pair of inner rings 108 and 109 and the outer rolling surfaces 120 and 121 of the outer ring 105 and the inner rolling surfaces 118 and 119 of the inner rings 108 and 109. With. As shown in FIG. 10, a notch 116 is provided on the outer peripheral surface of the tube portion 113 of the hub wheel 102, and the inner rings 108 and 109 are fitted into the notch 116. Further, a bolt mounting hole 112 is provided in the flange 101 of the hub wheel 102, and a hub bolt 141 for fixing the wheel and brake rotor 140 to the flange 101 is mounted in the bolt mounting hole 112.

  The shaft portion 123 of the outer joint member 103 is inserted into the tube portion 113 of the hub wheel 102. The shaft portion 123 has a screw portion 124 formed at the end of the anti-mouse portion, and a spline portion 125 is formed between the screw portion 124 and the mouse portion 107. Further, a spline portion 126 is formed on the inner peripheral surface (inner diameter surface) of the tube portion 113 of the hub wheel 102, and when the shaft portion 123 is inserted into the tube portion 113 of the hub wheel 102, The spline portion 125 engages with the spline portion 126 on the hub wheel 102 side.

  Then, the nut member 127 is screwed onto the threaded portion 124 of the shaft portion 123 protruding from the cylindrical portion 113, and the hub wheel 102 and the outer joint member 103 are connected. At this time, the inner end surface (back surface) 128 of the nut member 127 and the outer end surface 129 of the cylindrical portion 113 are in contact with each other, and the end surface 130 on the shaft portion side of the mouse portion 107 and the end surface 131 of the inner ring 109 are in contact with each other. That is, by tightening the nut member 127, the hub wheel 102 is sandwiched between the nut member 127 and the mouth portion 107 via the inner rings 108 and 109. At this time, the notch end surface 132 of the hub wheel 102 and the end surface 133 of the inner ring 108 are in contact with each other, and the end surfaces 130 of the mouth portion 107 and the end surface 131 of the inner ring 109 are in contact with each other. 135 and 136 are abutted. In this case, the outer diameter surface of the outer ring 105 becomes the fitting surface 105a and is press-fitted into the inner diameter surface 145a of the knuckle 145 on the vehicle body side.

  In recent years, a bearing (double-row angular bearing) in which inner and outer rings are formed by rolling has been proposed in order to reduce weight and cost (Patent Document 2). Here, cold rolling (cold rolling) is a processing method in which a material (blank) is rolled while being kept cold (normal temperature) without applying heat. In other words, two blanks (inner diameter and outer diameter) that are designed to have the inner and outer diameters smaller than the workpiece (finished product after machining) and basically the inner and outer diameter straight blanks (materials) to be machined. It is a processing method that forms a workpiece by rolling (rolling) while rotating it.

  As shown in FIG. 12, the double-row angular bearing described in Patent Document 2 corresponds to each of an outer ring 153 made of a pressed steel plate having double-row raceways 151 and 152 and a double-row raceway 151 and 152 of the outer ring 153. It has inner rings 156 and 157 having raceways 154 and 155, and double row rolling elements 158 arranged between the double row raceways 151 and 152 of the outer ring 153 and the races 154 and 155 of the inner rings 156 and 157. is there. In the bearing shown in FIG. 12, the tracks 151 and 152 are formed by forming the concave portion 161 in the central portion in the axial direction of the outer peripheral surface of the outer ring 153.

  Specifically, as shown in FIG. 14, the cold rolling machine includes an inner mandrel 175 and an outer diameter forming roll 176. Then, the material 170 is fitted on the mandrel 175, and the forming roll 176 is rotated around its axis as indicated by the arrow A in a state where the material 170 is sandwiched between the mandrel 175 and the forming roll 176.

  By the way, when the outer ring 153 having a shape as shown in FIG. 13B is formed, since the seal mounting grooves 165 and 166 are formed in the opening of the inner diameter surface, the outer ring material 170 is shown in FIG. Mold the material as shown. The outer ring material 170 is a cylindrical body whose inner diameter surface is composed of a small-diameter portion 171a in the middle in the axial direction, a medium-diameter portion 171b disposed on both sides of the small-diameter portion 171a, and a large-diameter portion 171c on the opening side. is there.

If the outer ring 153 is formed by cold rolling of the outer ring material 170, the medium diameter portion 171b of the material 170 constitutes the tracks 151 and 152, and the large diameter portions 171c and 171c on the opening side constitute the seal mounting grooves 165 and 166. To do.
JP 2007-120771 A Japanese Utility Model Publication No. 6-1835

  In the outer ring 153 shown in FIG. 13 (b), the tracks 151 and 152 are formed by forming the recess 161 in the axially central portion of the outer peripheral surface. When such a bearing using the outer ring 153 is used in the wheel bearing device shown in FIG. 10, a gap 176 (see FIG. 11) is formed by the recess 161 between the inner diameter surface of the knuckle.

  In such a case, the recess 161 reduces the fitting area with the inner diameter surface of the knuckle. For this reason, the fitting force for fixation cannot be obtained sufficiently, and there is a possibility that it cannot be firmly fixed. In particular, when the material of the knuckle is made of a light alloy having a coefficient of linear expansion larger than that of steel, the fitting tightening margin tends to decrease as the temperature rises, and creep may occur.

  In view of the above problems, the present invention provides a wheel bearing device that can be attached to a knuckle with a stable fitting force even when the temperature rises, and that can stably detect rotation speed detection and the like. I will provide a.

  The wheel bearing device of the present invention includes an inner ring having a rolling surface on an outer diameter surface, an outer ring having a rolling surface on an inner diameter surface, and an outer race surface of the outer ring and an inner race surface of the inner ring. A rolling bearing housed in a freely movable manner, at least an outer ring is formed by cold rolling, and an annular recess is formed in an axially central portion of the outer diameter surface of the outer ring. The annular recess of the outer ring is filled with a resin band made of heat-resistant synthetic resin, and a sensor unit is arranged on this resin band.

  The wheel bearing device of the present invention can improve the yield of materials such as an outer ring formed by cold rolling. In other words, unlike the rolling process in which an extra portion of the material is scraped off, the cold rolling can form a material that is thinner than the outer diameter of the product and does not cause material waste. In addition, productivity is higher than cutting because the machining time is short and the tool has a long life. Furthermore, although the tool (die) to be used needs to be replaced | exchanged according to a workpiece, the stable processing precision can be obtained. Furthermore, unlike the cutting process, the fiber flow (fibrous metal structure) is not cut, and the work surface is work-hardened by plastic deformation. Therefore, the processed product can obtain a strong strength.

  In the present invention, since the resin band made of heat-resistant synthetic resin is filled in the annular recess of the outer ring, it is possible to avoid a reduction in the area of the fitting surface with the knuckle due to the annular recess. And since the sensor unit is arrange | positioned at the resin band, the various test | inspections regarding the wheel bearing apparatus according to the sensor unit to arrange | position can be performed.

  A circumferential groove is formed on the outer peripheral surface of the resin band, and a signal discharge electrode continuous in the circumferential direction can be arranged in the circumferential groove. By arranging continuous signal discharge electrodes in the circumferential direction, the signal discharge electrode can be brought into contact with the electrode terminal on the knuckle side without performing phase alignment in the circumferential direction when the bearing is fitted to the knuckle. Can do.

  It is preferable that a probe that is urged by a spring element and whose contact comes into contact with the signal discharge electrode is disposed on the knuckle into which the outer ring is inserted. This stabilizes the signal extraction from the signal discharge electrode to the probe.

  The sensor unit may be a rotational speed detection unit, an outer ring displacement amount detection unit, a temperature detection unit, or a vibration detection unit.

It is preferable to use a resin having a linear expansion coefficient larger than that of the knuckle for the resin band. If such a resin band is used, the linear expansion coefficient is larger than that of the knuckle, and therefore, it is possible to prevent a decrease in the fitting tightening allowance even if the temperature rises. In particular, the resin is preferably a polyamide-based synthetic resin, and its linear expansion coefficient is preferably about 8 to 16 × 10 ⁻⁵ / ° C. Here, the linear expansion coefficient is an expansion coefficient when the unit temperature (1 ° C.) is increased.

  The maximum outer diameter portion of the resin band is preferably protruded in a range of 50 μm or less from the outer diameter surface of the outer ring. Thus, the resin band can be stably brought into pressure contact with the outer ring fitting surface of the knuckle by projecting the maximum outer diameter portion of the resin band.

  In the wheel bearing device of the present invention, since the outer ring is formed by cold rolling, the product yield and productivity can be improved, and cost reduction can be achieved. In addition, the outer ring can obtain stable processing accuracy and strong strength, and can achieve improved bearing quality. Moreover, the weight of the outer ring can be reduced and fuel can be reduced.

  Further, since the resin band is filled in the annular recess, it is possible to avoid a decrease in the area of the fitting surface with the knuckle due to the annular recess, and stable fixing becomes possible. Moreover, various inspections relating to the wheel bearing device according to the sensor unit to be arranged can be performed, and a highly accurate function can be exhibited.

  By arranging continuous signal discharge electrodes in the circumferential direction, the signal discharge electrode can be brought into contact with the electrode terminal on the knuckle side without performing phase alignment in the circumferential direction when the bearing is fitted to the knuckle. Therefore, the assembly workability can be improved.

  In the case where a probe that is urged by a spring element and is brought into contact with the contact element is arranged on the signal discharge electrode, the reliability of signal extraction is improved, and detection by the sensor unit can be performed more stably.

  Since the sensor unit may be a rotational speed detection unit, an outer ring displacement amount detection unit, a temperature detection unit, or a vibration detection unit, the wheel bearing device according to the element to be detected Can be configured.

  By using a resin band with a resin whose linear expansion coefficient is larger than that of the knuckle, it is possible to prevent a decrease in the tightening allowance between the knuckle and the outer ring of the bearing even when the temperature rises. Can demonstrate.

  By projecting the maximum outer diameter portion of the resin band, the resin band can be brought into pressure contact with the outer ring fitting surface of the knuckle, and the reliability of fixing the bearing to the knuckle can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a wheel bearing device (drive wheel bearing device) using a double row angular bearing of the first embodiment. The wheel bearing device includes a hub wheel 1 and a double row angular bearing 2 according to the present invention. And the constant velocity universal joint 3 are integrated.

  The constant velocity universal joint 3 includes a plurality of outer rings 5 serving as outer joint members, an inner ring 6 serving as an inner joint member disposed on the inner side of the outer ring 5, and a plurality of torque transmissions interposed between the outer ring 5 and the inner ring 6. The ball 7 and the cage 8 that is interposed between the outer ring 5 and the inner ring 6 and holds the ball 7 are configured as main members. The inner ring 6 is spline-fitted by press-fitting an end of a shaft (not shown) into the shaft hole inner diameter 6a and is coupled to the shaft so that torque can be transmitted.

  The outer ring 5 is composed of a mouse part 11 and a stem part (shaft part) 12. The mouse part 11 has a bowl shape opened at one end, and a plurality of track grooves 14 extending in the axial direction are circumferentially formed on the inner spherical surface 13 thereof. It is formed at equal intervals in the direction. The track groove 14 extends to the open end of the mouse portion 11. In the inner ring 6, a plurality of track grooves 16 extending in the axial direction are formed on the outer spherical surface 15 at equal intervals in the circumferential direction.

  The track groove 14 of the outer ring 5 and the track groove 16 of the inner ring 6 make a pair, and one ball 7 as a torque transmitting element can roll on each ball track constituted by the pair of track grooves 14 and 16. It is incorporated. The ball 7 is interposed between the track groove 14 of the outer ring 5 and the track groove 16 of the inner ring 6 to transmit torque. The constant velocity universal joint in this case is a Zepper type, but may be another constant velocity universal joint such as an undercut free type having a straight straight portion at the bottom of each track groove.

  The outer ring 5 and the inner ring 6 of the constant velocity universal joint 3 are made of, for example, medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the shoulder portions of the track grooves 14 and 16 and the mouth portion 11 of the outer ring 5. From the (bottom wall outer surface 11a), the outer peripheral surface (outer diameter surface) of the shaft portion 12 is subjected to a hardening process with a hardness of about 58 to 64 HRC by induction hardening or the like.

  The hub wheel 1 has a cylindrical portion 20 and a flange portion 21 provided at the end of the cylindrical portion 20 on the opposite joint side. Further, the shaft portion 12 of the outer ring 5 is inserted into the hole portion 22 of the cylindrical portion 20 of the hub wheel 1. The shaft portion 12 has a screw portion 40 formed at the end of the anti-mouse portion, and a spline portion 41 is formed between the screw portion 40 and the mouse portion 11. A spline portion 42 is formed on the inner peripheral surface (inner diameter surface) of the cylindrical portion 20 of the hub wheel 1. When the shaft portion 12 is inserted into the cylindrical portion 20 of the hub wheel 1, The spline portion 41 engages with the spline portion 42 on the hub wheel 1 side.

  Then, the nut member 43 is screwed onto the screw portion 40 of the shaft portion 12 protruding from the cylindrical portion 20, and the hub wheel 1 and the outer ring 5 are connected. At this time, a bolt mounting hole 32 is provided in the flange portion 21 of the hub wheel 1, and the hub bolt 33 is mounted in the bolt mounting hole 32. The hub wheel 1 is made of, for example, medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least the bottom surface or the end surface 70 of the notch has a hardness of about 58 to 64 HRC by induction hardening or the like. A curing treatment is applied.

  As shown in FIG. 2, the rolling bearing 2 includes an outer ring 25 in which double row outer rolling surfaces 26 and 27 are formed on the inner periphery, and an inner rolling that faces the outer rolling surfaces 26 and 27 of the outer ring 25 on the outer periphery. Rolled between a pair of inner races 24A and 24B on which running surfaces 28 and 29 are formed, outer raceway surfaces 26 and 27 of outer race 25 and inner raceway surfaces 28 and 29 of inner races 24A and 24B. And double row rolling elements 30. The rolling element 30 is held by a cage 31 interposed between the outer ring 25 and the inner rings 24A and 24B. A seal member S is mounted on both openings of the rolling bearing 2 (openings between the outer ring 25 and the inner rings 24A and 24B).

  In the outer ring 25, an annular recess 51 is formed in the axial central portion of the outer diameter surface 50, and a circumferential convex portion (bulging portion) 53 is provided in the axial central portion of the inner diameter surface 52 correspondingly. . Outer rolling surfaces 26 and 27 are formed on both sides of the circumferential convex portion 53, and seal mounting grooves 54 and 55 are formed on the outer sides of the outer rolling surfaces 26 and 27.

The annular recess 51 is filled with the resin band 17 corresponding to the shape of the annular recess 51. The resin band 17 is made of, for example, a polyamide-based synthetic resin, and has a linear expansion coefficient of 8 to 16 × 10 ⁻⁵ / ° C. Here, the linear expansion coefficient is an expansion coefficient when the unit temperature (1 ° C.) is increased. Further, the outer diameter surface 17a protrudes from the outer diameter surface 50 of the outer ring 25 by δ as shown in FIG. This δ is set to 0 μm <δ ≦ 50 μm.

  A plurality of circumferential small grooves 18 are formed in the outer diameter surface 17 a of the annular recess 51, and signal discharge electrodes 19 that are continuous in the circumferential direction are arranged in the circumferential small grooves 18. A strain gauge is attached to the bottom surface of the annular recess 51. Here, the strain gauge detects “strain”, which is a mechanical minute change generated according to applied force, as an electric signal.

  Specifically, the strain gauge is obtained by disposing a resistor (resistive wire or photo-etched resistance foil) on a base of an electrical insulator and connecting a lead wire to the resistor. For this reason, this base is attached to the bottom surface of the annular recess 51 and the lead wire is connected to the signal discharge electrode 19. That is, in the strain gauge, when strain occurs in the measurement object, the strain is transmitted to the resistor (wire / foil) via the strain gauge base.

  As shown in FIG. 1, a probe 83 is disposed on the knuckle N. The probe 83 includes a probe main body 83a and a terminal (contact) 83b protruding from the probe main body 83a. The probe main body 83a of the probe 83 is fitted into the through hole 82 provided in the knuckle N.

  An elastic member (spring element) is accommodated in the probe main body 83a, and the contact element 83b is pressed and biased toward the signal discharge electrode 19 by the spring element. The spring element can be composed of a spring member such as a coil spring or an elastic rubber material. Therefore, as shown in FIG. 4, the contact 83 b elastically contacts the signal discharge electrode 19. As shown in FIG. 1, a lead wire 84 is connected to the probe main body 83 a of the probe 83. The lead wire 84 is connected to a measuring instrument (not shown). The measuring instrument replaces the resistance value of the gauge with a change in voltage, amplifies it, and extracts it as digital or analog data.

  The inner ring 24A on the outboard side and the inner ring 24B on the inboard side can be configured by common parts. Note that the side closer to the outside of the vehicle when assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing). As shown in FIG. 2, the inner ring 24 (24 </ b> A, 24 </ b> B) is formed of a short cylindrical body having a thick portion 85 and a thin portion 86, and is transferred to an outer diameter surface between the thick portion 85 and the thin portion 86. A running surface 28 (29) is formed. The outer diameter surface of the thick portion 85 becomes the seal mounting surface 63. Further, the inner diameter surface becomes the hub wheel fitting surface 64.

  Next, a method for manufacturing the outer ring 25 of the rolling bearing 2 will be described. In this outer ring manufacturing method, as shown in FIG. 5, a long pipe material P is cut into a predetermined size to form a short material 34. Thereafter, a cold rolling process is performed on the material 34. Cold rolling (cold rolling) is a processing method in which a raw material (blank) is rolled while being kept cold (normal temperature) without applying heat. In other words, two blanks (inner diameter and outer diameter) that are designed to have the inner and outer diameters smaller than the workpiece (finished product after machining) and basically the inner and outer diameter straight blanks (materials) to be machined. It is a processing method that forms a workpiece by rolling (rolling) while rotating it.

  As shown in FIG. 6, as the material 34, the inner diameter surface 34 b includes a small diameter portion 37 at the center in the axial direction, middle diameter portions 38 a and 38 b on both sides in the axial direction of the small diameter portion 37, and a large diameter on the opening side. It is preferable to include the portions 39a and 39b.

  The outer ring material 34 may be a SUJ2 hardened product, a SUJ2 induction hardened product, or a medium and high carbon steel induction hardened product containing 0.40 to 0.80% by weight of carbon. Here, the submerged quenching is a method in which the entire product (up to the deep part) is raised to a necessary temperature with an electric furnace or the like and rapidly cooled to make the entire product a hard structure. Induction hardening is a method in which an article is placed between coils through which high-frequency current is communicated, the surface is heated by Joule heat associated with eddy current generated on the surface, and then rapidly cooled to form a hard structure only on the surface.

  In the cold rolling step, a cold rolling process is performed with a rolling apparatus as shown in FIG. The rolling device includes an inner diameter mandrel 47 and an outer diameter forming roll 48. An outer ring inner surface forming part 67 for forming the inner diameter surface of the outer ring 25 is formed on the outer peripheral surface of the mandrel 47, and an outer ring outer diameter surface forming part 68 for forming the outer diameter surface of the outer ring 25 on the outer diameter surface of the forming roll 48. Is formed.

  The outer ring inner diameter surface forming portion 67 includes rolling surface forming portions 67a and 67a and seal groove forming portions 67b and 67b. Further, the outer ring outer diameter surface forming portion 68 includes an annular recess forming portion 68a and seal mounting portions 68b and 68b.

  In this case, the material 34 is externally fitted to the mandrel 47, and the forming roll 48 is rotated around its axis while the material 34 is sandwiched between the mandrel 47 and the forming roll 48. As a result, the outer ring 25 can be formed. That is, the medium diameter portions 38a and 38b constitute the rolling surfaces 26 and 27, and the large diameter portions 39a and 39b constitute the seal mounting grooves 54 and 55.

  Thereafter, the surface is hardened by a heating furnace or the like and then subjected to cutting. In this case, cutting is performed on the seal mounting grooves 54 and 55 at the end portions in the axial direction, the rolling surfaces 26 and 27, both end surfaces 56 and 57, and the fitting surfaces 50a and 50a on the outer diameter surface. For this reason, these cuttings can be called hardened steel cutting. In other words, hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was called hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). . Since cutting is performed after quenching, the heat treatment deformation of the material can be removed in this cutting process. In addition, when quenching is performed, tensile residual stress tends to remain, and fatigue strength decreases as it is. For this reason, if the surface is cut, a compressive residual stress can be given to the outermost surface portion, thereby improving the fatigue strength.

  Next, a method for assembling the wheel bearing device configured as described above will be described. First, as shown in FIG. 1, a unit body in which a bearing 2 is incorporated in a hub wheel 1 is formed. That is, the fitting surfaces 64 and 64 of the inner rings 24A and 24B of the bearing 2 in the assembled state are press-fitted into the outer diameter surface 20a of the cylindrical portion 20 of the hub wheel 1. At this time, the end surface 85 a of the inner ring 24 </ b> A contacts the boss end surface 70 of the hub wheel 1.

  The unit body assembled in this way and the outer ring 5 of the constant velocity universal joint 3 are connected. At this time, the stem shaft portion 12 of the outer ring 5 is inserted into the hole portion 22 of the hub wheel 1, and the nut member 43 is screwed onto the screw portion 40 protruding from the hole portion 22 toward the outboard side. Thereby, the bottom wall outer surface 11a of the mouse part 11 contacts the end surface 85a of the inner ring 24B on the inboard side. At this time, the seat surface of the nut member 43 contacts the hub wheel 1 against the recessed surface 46 of the end surface 45 on the outboard side.

  For this reason, the pair of inner rings 24A, 24B is sandwiched between the boss part end face 70 and the bottom wall outer surface 11a of the mouse part 11 with the end faces (abutting faces) 86a, 86a being abutted against each other. A preload can be applied to 24B.

  In the wheel bearing device configured as described above, the knuckle fitting surface 50 a of the outer ring 25 of the rolling bearing 2 is press-fitted into the inner diameter surface 80 of the knuckle N. In this case, the outer diameters D1 and D2 of the knuckle fitting surface 50a are set slightly larger than the inner diameters D11 and D12 of the inner diameter surface 80 of the knuckle N. That is, the relative axial and circumferential deviation between the knuckle N and the outer ring 25 is regulated by the tightening allowance between the knuckle fitting surface 50a and the knuckle inner diameter surface 80.

  In this case, for example, when the hameai contact pressure / hameai area between the outer ring 25 and the knuckle N is taken as the hameai load, a value obtained by dividing the hameai load by the equivalent radial load of the rolling bearing is defined as a creep generation limit coefficient. The design specification of the outer ring 25 is set in consideration of the creep generation limit coefficient in advance.

  For this reason, due to the tightening allowance between the knuckle fitting surface 50a and the knuckle inner diameter surface 80, the outer ring 25 can be prevented from coming off in the axial direction and in the circumferential direction. Here, creep means that the bearing surface slightly moves in the circumferential direction due to insufficient fitting tightening allowance or poor processing accuracy of the mating surface, and the mating surface becomes mirrored, and in some cases, seizure or welding occurs with galling. Say.

  Further, a bulging portion 81 protruding toward the inner diameter side is provided on the knuckle inner diameter surface 80, and the end surface 25 on the inboard side of the outer ring 25 comes into contact with the bulging portion 81 by press-fitting the bearing 2 from the outboard side. ing. A retaining ring 82 is attached to the outer side of the knuckle inner diameter surface 80, and the outer ring 25 is maintained in a state of being sandwiched between the retaining ring 82 and the bulging portion 81.

  As shown in FIG. 1, a brake rotor 90 is attached to the hub wheel 1. The brake rotor 90 includes a center mounting portion 92 having an axial hole 91, and the center mounting portion 92 is fitted to the flange portion 21 of the hub wheel 1. The center mounting portion 92 includes a disc portion 92a having a through hole, and a short cylindrical portion 92b extending from the outer diameter portion of the disc portion 92a to the inboard side.

  In this case, the hub wheel 1 is composed of an end surface on the outboard side (an end surface 45 on the outboard side of the tubular portion 20 and an end surface on the outboard side of the flange portion 21 disposed continuously on the same plane. The disk portion 92a comes into contact with the end surface of the hub wheel 1 and the inner diameter surface on the disk portion 92a side of the short cylindrical portion 92b comes into contact with the outer diameter portion 21a of the flange portion 21 of the hub wheel 1. That is, the outer diameter portion 21 a of the flange portion 21 of the hub wheel 1 constitutes a brake pilot portion 95 that guides the brake rotor 90.

  In the wheel bearing device of the present invention, since the outer ring 25 is formed by cold rolling molding, it is possible to improve product yield and productivity, and achieve cost reduction. In addition, the outer ring can obtain stable processing accuracy and strong strength, and can achieve improved bearing quality. Further, the weight of the outer ring can be reduced, and fuel consumption can be reduced.

  Further, since the resin band 17 is filled in the annular recess 51, it is possible to avoid a reduction in the area of the fitting surface with the knuckle N due to the annular recess 51, and stable fixing becomes possible. Moreover, various inspections relating to the wheel bearing device according to the sensor unit to be arranged can be performed, and a highly accurate function can be exhibited.

  By arranging the signal discharge electrode 19 continuous in the circumferential direction, when the bearing 2 is fitted to the knuckle N, the signal discharge electrode 19 is connected to the electrode terminal on the knuckle N side without performing phase alignment in the circumferential direction. 83b can be brought into contact with each other, and assembly workability can be improved.

  In the case where the probe 83 that is urged by the spring element and is brought into contact with the contact 83b is arranged on the signal discharge electrode 19, the reliability of signal extraction is improved and the detection by the sensor unit can be performed more stably. it can.

  Further, in the wheel bearing device shown in FIG. 1, since the outer ring displacement amount detection unit is disposed, the acting load on the bearing can be calculated by detecting the displacement amount of the outer ring.

  Since the resin band 17 is made of a resin having a linear expansion coefficient larger than that of the knuckle, it is possible to prevent a decrease in fitting interference between the knuckle N and the outer ring 25 of the bearing 2 even if the temperature rises. Can exert the fitting force.

  By projecting the maximum outer diameter portion of the resin band 17, the resin band 17 can be brought into pressure contact with the outer ring fitting surface 80 of the knuckle, and the reliability of fixing the bearing 2 to the knuckle can be improved.

  Next, FIG. 8 shows a second embodiment. In this case, the inner rings 24A and 24B are also formed by cold rolling. The inner ring 24 (24 </ b> A, 24 </ b> B) includes a large diameter portion 60, a small diameter portion 61, and a tapered portion 62 between the large diameter portion 60 and the small diameter portion 61. In this case, the outer diameter surface of the large diameter portion 60 becomes the seal mounting surface 63, and the outer diameter surface of the tapered portion 62 becomes the rolling surface 28 (29). Further, the inner diameter surface of the small diameter portion 61 becomes the hub wheel fitting surface 64.

  Similarly to the outer ring 25, the inner ring 24 is formed by cold rolling of a raw material of the inner ring that is substantially the shape of the inner ring 24. This material is hardened in a heating furnace or the like to be hardened and then cut. That is, hardened steel cutting is performed. In this case, the hub wheel fitting surface 64, both end surfaces 65 and 66, the seal mounting surface 63, and the rolling surface 28 (29) are hardened steel cut. The material of the inner ring 24 is the same as that of the outer ring 25. The inner ring 24 may be formed by press work other than cold rolling.

  In the assembled state, the bottom wall outer surface 11a (see FIG. 1) of the mouse portion 11 abuts on the end surface 65 of the inner ring 24B on the inboard side, and the end surface 66 of the inner ring 24A and the end surface 66 of the inner ring 24B abut each other. The

  Also in this case, the annular recess 51 of the outer ring 25 is filled with the resin band 17 made of heat-resistant synthetic resin, and a sensor unit (outer ring displacement amount detection unit or the like) is disposed on the resin band 17.

  For this reason, the wheel bearing device using the bearing 2 shown in FIG. 8 also has the same effects as the wheel bearing device shown in FIG.

  Next, FIG. 9 shows 3rd Embodiment, In this case, it is a rotational speed detection unit as a sensor unit. That is, a through hole 96 is provided in the annular concave groove 51, and a resin connecting portion 97 integrated with the resin band 17 is fitted into the through hole 96, and the projecting portion end surface protruding from the through hole 96 toward the inner diameter side is provided. A rotation speed sensor (not shown) is provided. A magnetic encoder 98 is provided on the outer diameter surface of the small diameter portion of the inner ring 24B on the inboard side.

  The magnetic encoder 98 is made of, for example, a rubber magnet formed by mixing an elastomer such as rubber with a magnetic powder such as ferrite, and N and S poles are alternately formed in the circumferential direction. The rotational speed sensor includes a magnetic detection element that changes characteristics according to the flow direction of magnetic flux, such as a Hall element and a magnetoresistive element (MR element), and an IC in which a waveform circuit that adjusts the output waveform of the magnetic detection element is incorporated. Consists of. Further, the rotation speed sensor and the signal discharge electrode 19 are connected, and a signal from the rotation speed sensor is sent to the control means via the signal discharge electrode 19.

  In the rotational speed detection device configured as described above, when the magnetic encoder 98 rotates together with the inner ring 24 as the wheels (not shown) rotate, the output of the rotational speed sensor facing the magnetic encoder 98 changes. Since the frequency at which the output of the rotational speed sensor changes is proportional to the rotational speed of the wheel, the ABS is controlled by inputting the output signal of the rotational speed sensor to a control means (not shown).

  For this reason, the wheel bearing device using the bearing 2 shown in FIG. 9 also has the same effects as the wheel bearing device shown in FIG. In this case, the ABS can be stably controlled by the rotation speed detection device (rotation speed detection unit).

  In the embodiment, the sensor unit may be a temperature detection unit, a vibration detection unit, or the like. A temperature sensor is used as the temperature detection unit, and there are a contact type and a non-contact type as the temperature sensor. As a sensor in this case, a non-contact type radiation thermometer is used. Such a radiation thermometer includes a thermal type and a quantum type. Here, the thermal type uses a temperature change of a sensor element that receives infrared rays, and the quantum type uses a temperature change of the sensor element that receives a change of infrared photons.

  Thus, by detecting the temperature of the outer ring 25, abnormal heat generation of the bearing 2 can be detected. In such a case, an alarm or the like can be issued, the wheel bearing device can be found to be in an abnormal state, and a failure or accident can be prevented in advance.

  As the vibration detection unit, for example, a piezoelectric element is used, and by applying an alternating current signal, an electro-mechanical conversion function that generates mechanical vibration at the frequency of the alternating current signal is used as a vibrator to apply the vibration. An electro-mechanical conversion function that generates an AC signal having a vibration frequency can be used as a vibration detection sensor.

  Thus, by detecting the vibration of the outer ring 25, the abnormal vibration of the bearing 2 can be detected. In such a case, an alarm or the like can be issued, and it is found that the wheel bearing device is in an abnormal state, so that a failure or an accident can be prevented in advance.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the rolling element as a torque transmission unit of the bearing 2 However, a tapered roller may be used. As a blank for forming the outer ring 25, in the above embodiment, it is formed by a pipe material, but a round bar-shaped bar material is cut into a predetermined size, and this cut piece is formed by hot forging or the like. Also good. Further, in the above embodiment, the pair of inner rings are mounted with the abutting surfaces being abutted against each other, but an inner rolling surface in which the outer rolling surface of the outer ring faces the outer diameter surface of the hub wheel is formed. In addition, a stepped portion is formed on the inboard side of the outer diameter surface of the hub wheel, and an inner ring having an inner rolling surface facing the outer rolling surface on the outer periphery is fitted to this stepped portion. It may be made. Further, the wheel bearing device is a unit in which the hub wheel, the double row rolling bearing and the constant velocity universal joint are unitized, and the first outer rolling surface of the outer ring faces the outer diameter surface of the hub wheel. Even if the inner rolling surface is formed and the outer diameter surface of the outer joint member of the constant velocity universal joint is formed with the second inner rolling surface facing the second outer rolling surface of the outer ring. Good.

  In FIG. 9, the magnetic encoder 98 is attached to the inner ring 24 </ b> B on the inboard side in order to face (face) the rotation speed sensor disposed on the resin band 17 side. For this reason, the magnetic encoder 98 may be attached to the inner ring 24A on the outboard side as long as it can face (face to face) the rotational speed sensor.

It is sectional drawing of the wheel bearing apparatus which shows 1st Embodiment of this invention. It is an expanded sectional view of the rolling bearing of the wheel bearing device. It is an expanded sectional view of the resin band of the said wheel bearing apparatus. It is a principal part expanded sectional view of the said wheel bearing apparatus. It is a simplified process diagram which shows the outer ring | wheel manufacturing method of the rolling bearing of the said wheel bearing apparatus. It is sectional drawing of the blank used for the outer ring | wheel manufacturing method of the rolling bearing of the said wheel bearing apparatus. It is a simplified diagram of a cold rolling machine. It is sectional drawing of the rolling bearing of the wheel bearing apparatus which shows 2nd Embodiment of this invention. It is sectional drawing of the rolling bearing of the wheel bearing apparatus which shows 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the bearing of the conventional wheel bearing apparatus. It is a longitudinal cross-sectional view of the conventional bearing. It is a longitudinal cross-sectional view of the other conventional bearing. The other conventional manufacturing method of a bearing is shown, (a) is sectional drawing of the outer ring formation raw material of the conventional bearing, (b) is sectional drawing of the outer ring of the conventional bearing. It is a simplification figure of the manufacturing apparatus used for manufacture of the outer ring | wheel of the conventional bearing.

Explanation of symbols

17 resin band 17a outer diameter surface 18 circumferential small groove 19 signal discharge electrode 24 inner ring 24A, 24B inner ring 25 outer ring 26, 27 outer rolling surface 28, 29 rolling surface 30 rolling element 50 outer diameter surface 51 annular recess N knuckle

Claims (9)

An inner ring having a rolling surface on the outer diameter surface, an outer ring having a rolling surface on the inner diameter surface, and a rolling element housed in a freely rolling manner between the outer rolling surface of the outer ring and the inner rolling surface of the inner ring. A wheel bearing device in which at least the outer ring is formed by cold rolling, and an annular recess is formed in the axial central portion of the outer diameter surface of the outer ring,
A wheel bearing device, wherein a ring-shaped recess of the outer ring is filled with a resin band made of heat-resistant synthetic resin, and a sensor unit is arranged on the resin band.   The wheel bearing device according to claim 1, wherein a circumferential groove is formed on the outer peripheral surface of the resin band, and a signal discharge electrode continuous in the circumferential direction is disposed in the circumferential groove.   The wheel bearing device according to claim 2, wherein a probe that is urged by a spring element and whose contact comes into contact with the signal discharge electrode is arranged on a knuckle into which the outer ring is inserted.   The wheel bearing device according to claim 1, wherein the sensor unit is a rotational speed detection unit.   The wheel bearing device according to claim 1, wherein the sensor unit is an outer ring displacement amount detection unit.   The wheel bearing device according to claim 1, wherein the sensor unit is a temperature detection unit.   The wheel bearing device according to claim 1, wherein the sensor unit is a vibration detection unit.   The wheel bearing device according to any one of claims 1 to 7, wherein a resin having a linear expansion coefficient larger than a knuckle linear expansion coefficient is used for the resin band.   The wheel bearing device according to any one of claims 1 to 8, wherein a maximum outer diameter portion of the resin band is protruded within a range of 50 µm or less from an outer diameter surface of the outer ring.

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