JP2011117476A - Bearing device for wheel, equipped with rotational-speed detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, equipped with a rotational-speed detection device which improves assembling workability and secures sealing performance. <P>SOLUTION: A sensor cap 14 is made up of: a cap body 15 provided with a fitting section 15a of a cylindrical shape made of a synthetic resin and press suitable for the end of the inner side of an outer member 2 and a bottom section 15b that extends radially inward from the fitting section 15a; and a core metal 16 integrally molded to an opening of this cap body 15. A thin-walled section 20 is formed along the shape of a rotational-speed sensor 19 on an outer section in the radial direction of the bottom section 15b. The rotational-speed sensor 19 is arranged to face the thin-walled section 20 until it contacts or approaches the thin-walled section. A pulser ring 11 and the rotational-speed sensor 19 face each other with a predetermined axial air gap via the thin-walled section 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

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, in particular, a rotation speed detection device for detecting the rotation speed of the wheel, and a rotation speed for improving the sealing performance. The present invention relates to a wheel bearing device with a detection device.

  A wheel bearing with a rotation speed detecting device that rotatably supports a vehicle wheel with respect to a suspension device and controls an anti-lock brake system (ABS) to detect the rotation speed of the wheel. Devices are generally known. Conventionally, in such a wheel bearing device, a sealing device is provided between an inner member and an outer member that are in rolling contact with a rolling element, and a magnetic encoder in which magnetic poles are alternately arranged in a circumferential direction is provided as the sealing device. 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 achieve a more compact design, recently, a bearing for a wheel with a rotational speed detection device that also incorporates the rotational speed sensor in the bearing. A device has been proposed.

  A structure as shown in FIG. 6 is known as an example of such a wheel bearing device with a rotational speed detection device. This wheel bearing device with a rotational speed detection device is supported and fixed to a knuckle (not shown), and is inserted into the outer member 51 serving as a fixing member and the outer member 51 via double rows of balls 53 and 53. And an inner member 52. The inner member 52 includes a hub ring 55 and an inner ring 56 that is externally fitted to the hub ring 55.

  The outer member 51 integrally has a vehicle body mounting flange 51b on the outer periphery, and double row outer rolling surfaces 51a and 51a are formed on the inner periphery. On the other hand, the inner member 52 is formed with double-row inner rolling surfaces 55a and 56a facing the outer rolling surfaces 51a and 51a of the outer member 51 described above. Of the double row inner rolling surfaces 55 a and 56 a, one inner rolling surface 55 a is integrally formed on the outer periphery of the hub wheel 55, and the other inner rolling surface 56 a is formed on the outer periphery of the inner ring 56. The inner ring 56 is press-fitted into a shaft-shaped small-diameter step portion 55 b that extends in the axial direction from the inner rolling surface 55 a of the hub wheel 55. The double-row balls 53 and 53 are respectively accommodated between the rolling surfaces and are held by the cages 57 and 57 so as to be freely rollable.

  The hub wheel 55 integrally has a wheel mounting flange 54 for mounting a wheel (not shown) on the outer periphery, and a crimped portion 58 is formed by plastically deforming the end portion of the small diameter step portion 55b radially outward. The inner ring 56 is fixed in the axial direction by the caulking portion 58. A seal 59 and a cover 63 are 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 from the outside into the bearing. .

  A magnetic encoder 60 is press-fitted into the outer periphery of the inner ring 56. The magnetic encoder 60 is composed of a support ring 61 formed in an annular shape having a substantially L-shaped cross section by a magnetic metal plate, and an encoder body 62 attached to a side surface of the support ring 61. The encoder body 62 is made of a permanent magnet such as rubber mixed with ferrite powder, and S poles and N poles are alternately magnetized at equal intervals in the circumferential direction.

  The cover 63 is formed of a synthetic resin in a covered cylindrical shape, and its cylindrical portion 63a is press-fitted into the inner periphery of the outer side of the outer member 51, and the opening of the outer member 51 is closed by the lid 63b. Yes. A flange 64 that abuts the end surface of the outer member 51 is formed in the cylindrical portion 63 a, whereby the entire cover 63 is accurately positioned in the axial direction with respect to the outer member 51, and a sensor attached to the cover 63. 69 position management can be easily performed.

  Further, as shown in FIG. 7, a cylindrical sensor mounting portion 65 is formed on the lid portion 63b of the cover 63, and the insertion portion 69a of the sensor 69 is inserted into a sensor mounting hole 66 formed on the inner peripheral side thereof. ing. On the other hand, the cover 63 is integrally molded with a cored bar 67 formed in a covered cylindrical shape from the inner peripheral surface of the cylindrical portion 63a to the inner surface of the lid portion 63b. The metal core 67 includes a cylindrical portion 67a molded on the cylindrical portion 63a of the cover 63, and a lid portion 67b that forms the bottom of the cylindrical portion 67a, and is provided on the side facing the encoder main body 62 of the sensor mounting hole 66. The opening is closed.

  The core metal 67 is formed of a non-magnetic steel plate having a thickness of approximately 0.3 mm, and has a cover portion 67b, thereby increasing the strength of the cover 63 and being non-magnetic. Does not affect accuracy.

  The sensor 69 is attached to the cover 63 by inserting the insertion portion 69 a into the sensor attachment hole 66 of the cover 63. The insertion portion 69 a faces a part of the encoder main body 62 via a predetermined axial clearance across the lid portion 67 b of the core metal 67, and rotates the magnetic encoder 60 in the vicinity of the surface facing the encoder main body 62. The detector (not shown) which detects the magnetic field fluctuation | variation which generate | occur | produces by is built in. The detection unit outputs an electrical signal at one end of the output cable 68 in the sensor 69 via the cable 68.

  As described above, the opening of the sensor mounting hole 66 of the cover 63 on the side facing the encoder main body 62 is closed with the lid portion 67b of the cored bar 67 formed of a nonmagnetic steel plate in a covered cylindrical shape. Since the sensor mounting hole 66 does not penetrate the cover 63, there are few foreign substance intrusion paths into the apparatus, and the sealing performance of the entire apparatus is excellent (see, for example, Patent Document 1).

Japanese Patent No. 4286063

  In such a conventional wheel bearing device with a rotational speed detection device, the joint portion of the core metal 67 and the cover 63 made of synthetic resin, that is, the cylindrical portion 67a of the core metal 67, the cylindrical portion 63a of the cover 63, and the core metal. 67 and the lid portion 67b of the cover 63 are peeled off due to a difference in linear expansion coefficient due to a temperature change due to a thermal shock or the like, and a fine clearance is maintained, and the initial sealing performance is maintained over a long period of time. difficult.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a wheel bearing device with a rotational speed detection device that can improve the assembly workability and ensure sealing performance.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel for attaching a wheel to one end. A hub ring integrally having a mounting flange and formed with a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring. An inner member in which a double row of inner rolling surfaces facing the outer rolling surface is formed, and a double row of rolling members housed between the outer member and the inner member so as to roll freely. 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 a bottomed cylindrical shape that is internally fitted and fixed to an end on the inner side of the outer member. A sensor cap, and a predetermined axial air gap at a position corresponding to the pulsar ring. In the wheel bearing device with a rotational speed detection device in which the rotational speed sensor is disposed, the sensor cap is formed by injection molding a synthetic resin, and is a cylinder that is press-fitted into the inner periphery of the inner side end of the outer member. And a cap main body having a bottom portion extending radially inward from the fitting portion, and a cored bar integrally molded in the opening of the cap main body, and a radially outer portion of the bottom portion. A thin-walled portion is formed on one side, and the rotational speed sensor is opposed to the thin-walled portion until it abuts or approaches, and the pulsar ring and the rotational speed sensor pass through the thin-walled portion via a predetermined axial air gap. It is confronted.

  Thus, 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 a bottomed cylindrical sensor that is fitted and fixed to the inner side end of the outer member. A wheel bearing device with a rotational speed detecting device, wherein the rotational speed sensor is disposed at a position corresponding to the pulsar ring via a predetermined axial air gap. The sensor cap is formed by injection molding synthetic resin. A cap body having a cylindrical fitting portion press-fitted into the inner periphery of the inner side end of the outer member, and a cap body provided with a bottom portion extending radially inward from the fitting portion; and an opening portion of the cap body. A thin-walled portion is formed on the radially outer portion of the bottom portion, and is disposed opposite to the thin-walled portion until the rotational speed sensor abuts or approaches the pulsar ring via the thin-walled portion. Since the rotational speed sensors are opposed to each other through a predetermined axial air gap, a desired air gap can be obtained, and it is possible to improve the assembly workability by omitting complicated air gap adjustment. Since it is obstruct | occluded by the cap main body, the wheel bearing apparatus with a rotational speed detection apparatus which ensured sealing property can be provided. Moreover, since the core metal is integrally molded on the inner peripheral surface side of the resin fitting portion, it is possible to suppress deterioration in airtightness due to resin sag caused by temperature change or the like over a long period of time.

  Preferably, as in the invention described in claim 2, if the thin portion of the cap body is formed in a shape along the shape of the rotational speed sensor, the rotational speed sensor can be easily positioned in the circumferential direction. As a result, the assembly workability can be improved.

  Further, as in the invention according to claim 3, the thickness of the thin portion of the cap body is set to be within a range of 0.1 to 0.5 mm, which is 0.2 to 0.5 of the thickness of the bottom portion. Accordingly, sufficient strength and rigidity can be ensured, a desired magnetic flux density can be ensured, and detection accuracy can be increased.

  Further, if the cap body is made of a synthetic resin in which 10 to 50 wt% of GF is added to PA66 or PA6 · 12 as in the invention described in claim 4, the sensing performance of the rotational speed sensor is adversely affected. In addition, the corrosion resistance is excellent, the strength and rigidity are increased, and the durability can be improved over a long period of time.

  Moreover, if the fitting surface of the inner periphery of the end portion of the outer member is restricted to a chatter height of 3 μm or less as in the invention described in claim 5, the tightness of the fitting portion can be further enhanced. .

  Further, as in the invention described in claim 6, if the rotational speed sensor is disposed at a horizontal position with respect to the road surface, the outer member and the inner member are relatively inclined by a lateral load from the wheel. Even in this state, fluctuations in the air gap between the sensor and the pulsar ring can be suppressed, and stable detection accuracy can be obtained.

  Further, as in the invention described in claim 7, a mounting portion protruding in the axial direction is integrally projected at a substantially central portion in the radial direction of the bottom portion of the cap body, and a nut is embedded in the mounting portion by insert molding. At the same time, by fastening a fixing bolt to the nut via a mounting flange, if the rotational speed sensor is fixed to the mounting portion, the rotational speed sensor is mounted in a state where the inside of the bearing is closed with a sensor cap. It is possible to improve the sealing performance.

  Preferably, as in the invention according to claim 8, if the end surface on the inner side of the nut is set so as to be flush with or slightly protrude from the end surface of the mounting portion, The end face of the nut is brought into close contact with each other, improving the sealing performance and increasing the fastening force.

  If the nut is made of stainless steel as in the invention described in claim 9, rusting can be prevented over a long period of time, and durability can be improved.

  In addition, as in the invention described in claim 10, when the core metal is formed by pressing from a non-magnetic steel plate, high-accuracy speed detection without adversely affecting the sensing performance of the rotational speed sensor. It can be performed.

  Further, as in the invention described in claim 11, the pitch circle diameter of the outer rolling element row of the double row rolling element rows is set larger than the pitch circle diameter of the inner rolling element row. In addition, the rolling element diameter of the outer rolling element row is set smaller than the rolling element diameter of the inner rolling element row, and the number of rolling elements in the outer rolling element row is set to the inner rolling element row. If the number of rolling elements is set to be greater than the number of rolling elements, the bearing rigidity of the outer side portion can be increased compared to the inner side, the life of the bearing can be increased, and the outer side of the outer member can be increased. High rigidity can be achieved while suppressing the diameter.

  The wheel bearing device with a rotational speed detection device according to the present invention is integrally formed with an outer member in which a double row outer rolling surface is integrally formed on the inner periphery and a wheel mounting flange for mounting a wheel on one end. And a hub ring 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 opposing double-row inner rolling surfaces are 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 the inner ring And a pulsar ring whose characteristics are alternately changed at equal intervals in the circumferential direction, and a bottomed cylindrical sensor cap that is internally fitted and fixed to the inner side end of the outer member. Rotate through a predetermined axial air gap to a position corresponding to the pulsar ring. In the wheel bearing device with a rotational speed detection device in which the speed sensor is arranged, the sensor cap is formed by injection molding a synthetic resin, and is fitted into a cylindrical fit that is press-fitted into the inner periphery of the outer side end of the outer member. And a cap main body having a bottom portion extending radially inward from the fitting portion, and a cored bar integrally molded in the opening of the cap main body, and a radially outer portion of the bottom portion. A thin portion is formed, and the rotational speed sensor is opposed to the thin portion until it abuts or approaches, and the pulsar ring and the rotational speed sensor are opposed to each other through a predetermined axial air gap through the thin portion. As a result, a desired air gap can be obtained, complicated air gap adjustment can be omitted, and assembly workability can be improved, and the detection unit is closed by the cap body. Since, it is possible to provide a rotational speed detector equipped wheel support bearing assembly for securing the sealability. Moreover, since the core metal is integrally molded on the inner peripheral surface side of the resin fitting portion, it is possible to suppress deterioration in airtightness due to resin sag caused by temperature change or the like over a long period of time.

1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device with a rotation speed detection device according to the present invention. It is a side view of FIG. It is a principal part enlarged view which shows the detection part of FIG. (A) is 2nd Embodiment of the wheel bearing apparatus with a rotational speed detection apparatus concerning this invention, and is a longitudinal cross-sectional view which shows a sensor cap single-piece | unit, (b) is a side view of (a). It is a side view at the time of vehicle mounting same as the above. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus with a rotational speed detection apparatus. It is a principal part enlarged view of FIG.

  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. A double row rolling element accommodated between the faces in a freely rolling manner, a pulsar ring that is fitted on the inner ring and has alternating characteristics in the circumferential direction at equal intervals, and an inner side of the outer member A bottomed cylindrical sensor cap that is fitted inside and fixed to the end of the pulsar In a wheel bearing device with a rotational speed detection device in which a rotational speed sensor is disposed at a position corresponding to a predetermined axial air gap, the sensor cap is formed by injection molding synthetic resin, A cap body having a cylindrical fitting portion press-fitted into the inner periphery of the inner side end of the member, and a bottom portion extending radially inward from the fitting portion, and an opening of the cap body are integrally molded A thin metal part is formed along the shape of the rotational speed sensor on the radially outer part of the bottom part along the core bar, and the thin part is disposed opposite to the rotational speed sensor until it abuts or approaches, The pulsar ring and the rotational speed sensor are opposed to each other through a predetermined axial air gap through the thin portion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device with a rotational speed detection device according to the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a detection unit of FIG. It is a principal part enlarged view. 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 with a rotational speed detection device is called the third generation on the driven wheel side, and is a double row of rollers accommodated between the inner member 1 and the outer member 2 and between both members 1 and 2 so as to be freely rollable. Rolling elements (balls) 3a and 3b are provided. 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 portion 4b is formed via an axial portion 4d extending in the axial direction from the surface 4a. Hub bolts 6a are planted on the wheel mounting flange 6 at equal intervals in the circumferential direction.

  A mortar-shaped recess 10 extending in the axial direction is formed at the outer end of the hub wheel 4. The recess 10 is formed up to the groove bottom of the inner side rolling surface 4a on the outer side by forging, and the thickness of the outer side of the hub wheel 4 is set to be substantially uniform.

  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 3a and 3b 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 formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner raceway surface 4a and the base portion 6b on the inner side of the wheel mounting flange 6 are connected to the small diameter step portion 4b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. 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 2c to be attached to a knuckle (not shown) on the outer periphery, and the outer side outer rolling facing the inner rolling surface 4a of the hub wheel 4 on the inner periphery. The surface 2a and the inner side outer rolling surface 2b facing the inner rolling surface 5a of the inner ring 5 are integrally formed. Double-row rolling elements 3a and 3b are accommodated between these rolling surfaces and are held by the cages 7 and 8 so as to roll freely. A seal 9 is attached to an opening on the outer side of the annular space formed between the outer member 2 and the inner member 1, and a sensor cap 14 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 the double row outer rolling surfaces 2a and 2b have a surface hardness in the range of 58 to 64HRC by induction hardening. It has been cured. In addition, although the double row angular contact ball bearing which used the ball | bowl for the rolling elements 3a and 3b was illustrated here, not only this but the double row tapered roller bearing using a tapered roller may be sufficient. In addition, the second generation or the fourth generation structure is not limited to the third generation structure on the driven wheel side.

  In the present embodiment, the pitch circle diameter PCDo of the outer rolling element 3a row is set larger than the pitch circle diameter PCDi of the inner rolling member 3b row, and the outer rolling element 3a row of rolling elements. The diameter do is set to a smaller diameter (do <di) than the rolling element diameter di of the inner rolling element 3b row. Due to the difference between the pitch circle diameters PCDo and PCDi and the rolling element diameters do and di, the number of rolling elements Zo in the outer rolling element 3a row is set larger than the number of rolling elements Zi in the inner rolling element 3b row. (Zo> Zi). Thereby, the bearing rigidity of an outer side part can be increased compared with an inner side, and lifetime improvement of a bearing can be achieved. Here, the outer side rolling elements 3a and the inner side rolling elements 3b are illustrated as having different sizes. However, the present invention is not limited to this, and the same size may be used in both rows.

  A pulsar ring 11 is press-fitted into the outer periphery of the inner ring 5. The pulsar ring 11 includes a support ring 12 formed in an annular shape, and a magnetic encoder 13 integrally joined to the side surface of the support ring 12 by vulcanization adhesion or the like. This magnetic encoder 13 constitutes 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 alternately magnetizing magnetic poles N and S in the circumferential direction.

  The support ring 12 is formed by pressing from a ferromagnetic steel plate, for example, a ferritic stainless steel plate (JIS standard SUS430 or the like) or a rust-proof cold rolled steel plate (JIS standard SPCC or the like). As shown in an enlarged view in FIG. 3, it has a cylindrical portion 12a that is press-fitted into the inner ring 5, and a vertical plate portion 12b that extends radially inward from the cylindrical portion 12a. Yes. The magnetic encoder 13 is joined to the side surface on the inner side of the upright plate portion 12b.

  The sensor cap 14 is fitted and fixed to the inner end of the outer member 4 and closes the opening of the outer member 2. The sensor cap 14 includes a bottomed cylindrical cap body 15 formed by injection molding a synthetic resin, and a core 16 integrally molded in the opening of the cap body 15. The metal core 16 is formed in an annular shape having an L-shaped cross section by press-forming a corrosion-resistant stainless steel plate or cold-rolled steel plate (JIS standard SPCC system or the like). In particular, the metal core 16 is formed of a non-magnetic steel plate, for example, an austenitic stainless steel plate (JIS standard SUS304, etc.) so as not to adversely affect the sensing performance of the rotational speed sensor 19 described later. It is preferable. Moreover, since the cored bar 16 is integrally molded on the inner peripheral surface side of the resin fitting portion, it is possible to suppress deterioration in airtightness due to resin sag caused by temperature change or the like over a long period of time.

  The cap body 15 is formed by injection molding from a thermoplastic synthetic resin such as PA (polyamide) 66 or PA 6/12, and further added with a fibrous reinforcing material such as GF (glass fiber) in an amount of 10 to 50 wt%. Is preferred. As a result, the sensing performance of the rotation speed sensor 19 is not adversely affected, the corrosion resistance is excellent, the strength and rigidity are increased, and the durability can be improved over a long period of time. It is even better. The cap body 15 can be exemplified by synthetic resins that can be injection molded, such as polyphenylene sulfide (PPS), PPA (polyphthalamide), PBT (polybutylene terephthalate), etc., in addition to the materials described above. Moreover, as a fibrous reinforcement, not only GF but CF (carbon fiber), an aramid fiber, a boron fiber, etc. can be illustrated other than this.

  In the present embodiment, the cap body 15 includes 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 bottom portion 15b that extends radially inward from the fitting portion 15a. I have. And the fitting surface of the edge part inner periphery of the outer member 2 is controlled by chatter height of 3 micrometers or less. Thereby, the airtightness of the fitting part 15a of the cap main body 15 is improved.

  Further, a mounting portion 17 protruding in the axial direction is integrally provided at a substantially central portion in the radial direction of the bottom portion 15a, and a nut 18 is embedded in the mounting portion 17 by insert molding. Then, the rotation speed sensor 19 is fixed to the mounting portion 17 by fastening the fixing bolt to the female screw 18a of the nut 18 via a mounting flange (not shown). An annular groove 18b is formed on the outer periphery of the nut 18 to prevent the nut 18 from moving in the axial direction. Here, the nut 18 is formed of a steel material having an antirust property such as austenitic stainless steel (JIS standard SUS304 system) or ferritic stainless steel (JIS standard SUS430 system). Thereby, rusting can be prevented over a long period of time, and durability can be improved.

  The end surface 18c on the inner side of the nut 18 is set so as to be flush with or slightly protrude from the end surface 17a of the mounting portion 17. As a result, the fixing bolt and the end face 18c of the nut 18 are brought into close contact with each other at the time of fastening, thereby improving the sealing performance and increasing the fastening force.

  Here, a thin circular portion 20 is formed at a position corresponding to the magnetic encoder 13 in the radially outer portion of the bottom portion 15 b of the cap body 15 (see FIG. 2), and the rotational speed sensor 19 is formed in the thin portion 20. Are placed opposite until they collide or approach. And the change of the magnetic flux of the magnetic encoder 13 is detected by the rotational speed sensor 19 through the thin part 20, and the rotational speed of the wheel is detected. As a result, a desired air gap can be obtained, and it is possible to improve the assembly workability by omitting complicated air gap adjustment, and the detection unit is closed by the cap body 15, which affects the sensing performance. It is possible to provide a wheel bearing device with a rotation speed detection device that ensures sealing performance without any problem. Note that the thickness t0 of the thin portion 20 is 0.2 to 0.5 of the thickness t of the bottom portion 15b, and is set in a range of 0.1 to 0.5 mm. If the thickness t0 is less than 0.1 mm, the strength and rigidity are insufficient, and there is a possibility of colliding with other parts at the time of assembly and causing deformation or breakage. On the other hand, if the thickness t0 exceeds 0.5 mm, the air gap becomes too large to obtain the required magnetic flux density.

  The rotational speed sensor 19 incorporates a magnetic detecting element such as a Hall element, a magnetoresistive element (MR element), etc. that changes its characteristics according to the flow direction of the magnetic flux, and a waveform shaping circuit that adjusts the output waveform of the magnetic detecting element. It is composed of an IC or the like, and constitutes an automobile ABS that detects the rotational speed of a wheel and controls its rotational speed.

  FIG. 4A is a longitudinal sectional view showing a sensor cap alone in a second embodiment of a wheel bearing device with a rotational speed detection device according to the present invention, and FIG. 4B is a side view of FIG. 5 is a side view when the vehicle is mounted. Note that this embodiment is basically different from the first embodiment (FIG. 2) described above except that the configuration of the cap main body is partially different, and other parts or parts having the same function, the same part, or the same function. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  The sensor cap 21 includes a bottomed cylindrical cap body 22 formed by injection molding a synthetic resin, and a cored bar 16 integrally molded in an opening of the cap body 22. The cap body 22 includes a cylindrical fitting portion 15a that is press-fitted into the inner periphery of an end portion of an outer member (not shown), and a bottom portion 22a that extends radially inward from the fitting portion 15a. 22 is formed by injection molding from a non-magnetic special ether-based synthetic resin material such as PPS, and a reinforcing material such as GF is added in an amount of 30 to 50 wt%. As a result, the sensing performance of the rotation speed sensor 19 is not adversely affected, the corrosion resistance is excellent, the strength and rigidity are increased, and the durability can be improved over a long period of time. Moreover, since the cored bar 16 is integrally molded on the inner peripheral surface side of the resin fitting portion, it is possible to suppress deterioration in airtightness due to resin sag caused by temperature change or the like over a long period of time.

  A thin portion 23 is formed on a part of the bottom 22 a of the cap body 22. The thin portion 23 is formed at a position corresponding to a magnetic encoder (not shown) in the radially outer portion, and is disposed so as to face the rotational speed sensor 19 until it abuts or approaches. Since the thin-walled portion 23 is formed along the shape of the rotational speed sensor 19, a desired air gap can be obtained, and the rotational speed sensor 19 can be easily positioned in the circumferential direction, thereby improving assembly workability. Can be achieved.

  Further, as shown in FIG. 5, the rotational speed sensor 19 is disposed so as to be in a horizontal position with respect to the road surface in a vehicle-mounted state. As a result, even when the outer member and the inner member are relatively inclined due to a lateral load from the wheel, fluctuations in the air gap between the rotational speed sensor 19 and the magnetic encoder can be suppressed, and stable detection accuracy can be achieved. Obtainable.

  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. 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 with a rotation speed detection device according to the present invention can be applied to a wheel bearing device of an inner ring rotation type having any structure such as a drive wheel, a driven wheel, or a rolling element such as a ball or a tapered roller. .

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a, 2b Outer rolling surface 2c Car body mounting flange 3a Outer side rolling element 3b Inner side rolling element 4 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 4c Clamping part 4d Shaft-shaped part 5 Inner ring 6 Wheel mounting flange 6a Hub bolt 6b Inner side base 7 and 8 of wheel mounting flange Cage 9 Seal 10 Recess 11 Pulsar ring 12 Support ring 12a Cylindrical part 12b Standing plate part 13 Magnetic encoder 14, 21 Sensor cap 15, 22 Cap body 15a Fitting portion 15b, 22a Bottom portion 16 Core 17 Mounting portion 17a End surface 18 of mounting portion Nut 18a Female thread 18b Annular groove 18c End surface 19 on the inner side of nut Rotational speed sensor 20, 23 Thin portion 51 Outer side Member 51a Outer rolling surface 51b Car body mounting flange 52 Inner member 53 Ball 54 Wheel mounting flange 5 Hub wheel 55a, 56a Inner rolling surface 55b Small diameter step part 56 Inner ring 57 Cage 58 Clamping part 59 Seal 60 Magnetic encoder 61 Support ring 62 Encoder main body 63 Cover 63a Tube part 63b, 67b Cover part 64 Flange 65 Sensor attachment part 66 Sensor mounting hole 67 Core 67a Tubular portion 68 Cable 69 Sensor 69a Insertion portion di Rolling element diameter of inner side rolling element row do Rolling element diameter of outer side rolling element row H1 Cap thickness H2 Cap disk Thickness PCDi Inner side rolling element row pitch circle diameter PCDo Outer side rolling element row pitch circle diameter t0 Thin part thickness t Bottom thickness Zi Inner side rolling body row rolling element number Zo Outer Number of rolling elements in the side rolling element row

Claims (11)

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 housed 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;
A bottomed cylindrical sensor cap fitted and fixed to the inner side end of the outer member;
In the wheel bearing device with a rotational speed detection device in which a rotational speed sensor is disposed through a predetermined axial air gap at a position corresponding to the pulsar ring,
The sensor cap is formed by injection-molding synthetic resin, and has a cylindrical fitting portion that is press-fitted into the inner periphery of the inner side end of the outer member, and a bottom portion that extends radially inward from the fitting portion. A cap body and a cored bar integrally molded in the opening of the cap body, and a thin portion is formed in a radially outward portion of the bottom portion, and the rotational speed sensor collides with the thin portion. Alternatively, the wheel bearing device with a rotational speed detecting device is disposed so as to face each other and the pulsar ring and the rotational speed sensor are opposed to each other through a predetermined axial air gap through the thin portion.   The wheel bearing device with a rotational speed detection device according to claim 1, wherein a thin portion of the cap body is formed in a shape along the shape of the rotational speed sensor.   The rotational speed detection according to claim 1 or 2, wherein the thickness of the thin part of the cap body is set to a range of 0.1 to 0.5 mm, which is 0.2 to 0.5 of the thickness of the bottom part. Wheel bearing device with device.   The wheel bearing device with a rotational speed detection device according to any one of claims 1 to 3, wherein the cap body is formed of a synthetic resin in which GF is added to PA66 or PA6 / 12 in an amount of 10 to 50 wt%.   The wheel bearing device with a rotational speed detecting device according to claim 1, wherein a fitting surface on an inner periphery of an end portion of the outer member is restricted to a chatter height of 3 µm or less.   The wheel bearing device with a rotation speed detection device according to claim 1, wherein the rotation speed sensor is disposed in a horizontal position with respect to a road surface.   A mounting portion projecting in the axial direction is integrally provided at a substantially central portion in the radial direction of the bottom portion of the cap body, and a nut is embedded in the mounting portion by insert molding, and a fixing bolt is attached to the nut via a mounting flange. The wheel bearing device with a rotational speed detection device according to any one of claims 1 to 4, wherein the rotational speed sensor is fixed to the mounting portion by fastening.   The wheel bearing device with a rotation speed detecting device according to claim 7, wherein an end surface on the inner side of the nut is set so as to be flush with or slightly protrude from an end surface of the mounting portion.   The wheel bearing device with a rotation speed detection device according to claim 7 or 8, wherein the nut is made of stainless steel.   The wheel bearing device with a rotation speed detection device according to claim 1, wherein the core metal is formed from a non-magnetic steel plate by pressing.   The pitch circle diameter of the outer rolling element row of the double row rolling element rows is set larger than the pitch circle diameter of the inner rolling element row, and the rolling element diameter of the outer rolling element row is set. Is set to be smaller than the rolling element diameter of the inner side rolling element row, and the number of rolling elements of the outer side rolling element row is set to be larger than the number of rolling elements of the inner side rolling element row. A wheel bearing device with a rotational speed detection device according to claim 1.

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