JP6394051B2 - Rolling bearing unit with rotational speed detector - Google Patents

Description

  The present invention relates to an improvement in a rolling bearing unit with a rotational speed detecting device for rotatably supporting a vehicle wheel (driven wheel) with respect to a suspension device and detecting the rotational speed of the wheel.

  2. Description of the Related Art Conventionally, various structures are known as rolling bearing units with a rotational speed detecting device for rotatably supporting a wheel on a suspension device of an automobile and detecting the rotational speed of the wheel. In any structure, the detection part of the sensor supported and fixed to the non-rotating part is opposed to the detection surface of the encoder supported and fixed to a part of the hub that rotates together with the wheel. And it is comprised so that the rotational speed of the said wheel which rotates with this encoder may be calculated | required based on the frequency or the period of the output signal of this sensor which changes with rotation of the said encoder.

  This encoder is used to prevent the encoder constituting the rolling bearing unit with such a rotational speed detection device from being damaged by adhesion of muddy water, dust, etc., or when foreign particles such as magnetic powder adhere to this encoder. In order to prevent the reliability of rotation speed detection from being impaired, a structure in which the encoder is separated from the outside by a cap made of a nonmagnetic plate has been conventionally known, as described in Patent Document 1, for example. FIG. 4 shows an example of the structure described in Patent Document 1 among them.

  This rolling bearing unit 1 with a rotational speed detection device is formed by combining a rolling bearing unit 2 and a rotational speed detection device 3. Among them, the rolling bearing unit 2 includes an outer ring 4, a hub 5, and a plurality of rolling elements 6 and 6. Outer ring 4 has double-row outer ring raceways 7a and 7b on the inner peripheral surface and stationary flange 8 on the outer peripheral surface. And the outer ring | wheel 4 is supported by the knuckle 9 which comprises a suspension apparatus, and does not rotate in use condition. The hub 5 is formed by coupling and fixing a hub body 10 and an inner ring 11 by a caulking portion 12. The hub 5 has double-row inner ring raceways 13 a and 13 b on the outer peripheral surface, and is arranged on the inner diameter side of the outer ring 4. The outer ring 4 is supported concentrically. Further, the outer end of the hub body 10 in the axial direction (outside with respect to the axial direction means a side that is outside the width direction of the vehicle body when assembled to the suspension device. The same applies throughout the present specification and claims. )), A rotation-side flange 14 for supporting the wheel is provided at a portion protruding outward in the axial direction from the axially outer end opening of the outer ring 4. The rolling elements 6 and 6 are held by the cages 15 and 15 between the outer ring raceways 7a and 7b and the inner ring raceways 13a and 13b. It is provided so that it can roll freely. Furthermore, both axial ends of the internal space 16 in which the rolling elements 6 and 6 are installed are closed by a seal ring 17 and a cap 18.

  The cap 18 is made of a nonmagnetic plate such as a nonmagnetic metal plate such as an aluminum alloy plate or an austenitic stainless steel plate. Such a cap 18 includes a bottom plate portion 19 and a cylindrical portion 20 bent at a right angle from the outer peripheral edge of the bottom plate portion 19 in the axially outward direction. In the structure of FIG. 4, since the rolling bearing unit 2 for driven wheels (rear wheel of FF vehicle, front wheel of FR vehicle, MR vehicle) is targeted, the bottom plate portion 19 is opened in the axial inner end of the outer ring 4. The inner part in the axial direction means the side closer to the center in the width direction of the vehicle body in the state assembled to the suspension device (the same applies to the entire specification and claims). .

  On the other hand, the rotational speed detection device 3 includes an encoder 21 and a sensor unit 22. The encoder 21 includes a support ring 23 having a magnetic metal plate having an L-shaped cross section and a ring shape as a whole, and an encoder body 24 made of a permanent magnet such as a rubber magnet. The encoder main body 24 is magnetized in the axial direction, and by alternately changing the magnetization direction with respect to the circumferential direction at equal intervals, the S pole and the N pole are provided on the inner side surface in the axial direction, which is the detected surface. These are arranged alternately and at equal intervals. The detected surface of the encoder main body 24 is in close proximity to the axially outer side surface (inner surface) of the cap 18 with a minute gap therebetween. In other words, the cap 18 is pushed into the inner end of the outer ring 4 in the axial direction until the outer surface in the axial direction of the bottom plate 19 is in close proximity to the detected surface of the encoder body 24.

Further, the sensor unit 22 includes a sensor (not shown) and a sensor holder 25. Among these sensors, a magnetic detection element such as a Hall element or a magnetoresistive element is provided in the detection section, and changes an output signal in response to a change in characteristics of the detection surface of the encoder body 24. The sensor holder 25 is formed by injection-molding synthetic resin, and includes a holder main body 26 that holds the sensor and a mounting plate portion 27 that is fixed to the knuckle 9. Such a sensor unit 22 has a male screw portion of a bolt 29 inserted through a through hole formed in the mounting plate portion 27 in a state where the holder body 26 is inserted into a sensor insertion hole 28 formed in the knuckle 9. The knuckle 9 is fixed to the knuckle 9 by screwing into a female screw portion of a bottomed screw hole 30 formed in the knuckle 9.

As described above, the detection part of the sensor held by the sensor holder 25 is brought into contact with the inner side surface (outer surface) in the axial direction of the bottom plate part 19 while being supported and fixed to the knuckle 9. In this state, the detection portion faces the detection surface of the encoder body 24 through the bottom plate portion 19. The encoder main body 24 in this state, rotates together with the hub 5, wherein the vicinity of the detection portion of the sensor, and the S and N poles that exist in the detected face passes alternately output of the sensor Changes. Since the frequency of this change is proportional to the rotational speed of the hub 5 and the period of the change is inversely proportional to the rotational speed, the rotational speed of the wheel fixed to the hub 5 can be obtained based on either.

  In the case of the conventional structure shown in FIG. 4 as described above, the permanent magnet encoder body 24 and the external space are separated by the cap 18 made of a non-magnetic plate. It can prevent foreign matter such as magnetic powder from adhering. Therefore, it is possible to ensure the reliability of rotation speed detection using the encoder body 24 while keeping the detected surface in a clean state. However, there is room for improvement in the following points from the aspect of further improving the reliability of the rotational speed detection.

  In order to change the output signal of the sensor sufficiently with the rotation of the encoder body 24, it is necessary to sufficiently increase the positioning accuracy of the sensor with respect to the encoder body 24. On the other hand, in the case of the conventional structure, the sensor is supported and fixed to the knuckle 9, and since there are many members existing between the encoder body 24 and the sensor, it is difficult to ensure the positioning accuracy. . In particular, the positioning accuracy between the outer ring 4 and the knuckle 9 is not sufficiently high in terms of rotational speed detection, which is disadvantageous in terms of ensuring the amount of change in the output signal of the sensor.

Further, in the case of the above-described conventional structure, the detection portion of the sensor is opposed to the detection surface of the encoder body 24 through the bottom plate portion 19 of the cap 18. Therefore, the cap 18 is made of a nonmagnetic plate such as a nonmagnetic metal plate such as an aluminum alloy plate or an austenitic stainless steel plate. Such a metal made of a non-magnetic material is expensive and difficult to press, which may increase the production cost.
In addition, when the austenitic stainless steel plate is pressed, the stainless steel plate may become magnetized. In this case, a process (heat treatment or the like) for removing magnetism is required after press working, which may increase manufacturing costs.
In the case of the above-described conventional structure, since the detection portion of the sensor is opposed to the detection surface of the encoder body 24 via the bottom plate portion 19 of the cap 18, the detection portion of the sensor, The distance (air gap) between the encoder body 24 and the detected surface is likely to be large, which may be disadvantageous from the viewpoint of ensuring the amount of change in the output signal of the sensor.

JP 2000-249138 A

  In view of the circumstances as described above, the present invention has been invented to realize a structure of a rolling bearing unit with a rotational speed detection device that can easily secure positioning accuracy in the axial direction between an encoder and a sensor and that can suppress manufacturing costs. Is.

The rolling bearing unit with a rotational speed detection device of the present invention is used to rotatably support a wheel for a driven wheel with respect to a suspension device such as a knuckle, and includes an outer ring, a hub, and a plurality of rolling elements. And an encoder, a cap, and a sensor unit.
Among these, the outer ring has a double row outer ring raceway on the inner peripheral surface, and does not rotate during use.
The hub has a double-row inner ring raceway on the outer peripheral surface, and a rotation-side flange for supporting a wheel on a portion of the outer peripheral surface that protrudes axially outward from the axial outer end of the outer ring. And is supported concentrically with the outer ring on the inner diameter side of the outer ring.
Each of the rolling elements is provided between the outer ring raceways and the inner ring raceways so as to be capable of rolling plurally for each row.
The encoder is formed by alternately changing the magnetic characteristics of the inner surface in the axial direction with respect to the circumferential direction, and is supported concentrically with the hub at the inner end in the axial direction of the hub.
The cap is attached to an inner end portion in the axial direction of the outer ring and closes an opening portion in the axial direction of the outer ring.
The sensor unit includes a sensor and a sensor holder.
Among these sensors, the output signal is changed in response to a change in the magnetic characteristics of the detected surface of the encoder while facing the detected surface of the encoder in the axial direction.
The sensor holder is supported by the cap while holding the sensor.

In particular, in the case of the rolling bearing unit with a rotational speed detection device of the present invention, the cap includes a cap body, a sensor mounting nut, and a rubber member.
Among these, the cap main body is made of a metal and has a bottomed cylindrical shape, and includes a cap cylindrical portion, a cap bottom portion, a sensor through hole, and a nut through hole .
Among these, the cap cylindrical portion is fitted and fixed to the inner end portion in the axial direction of the outer ring.
The cap bottom portion closes the axial inner end opening of the cap cylindrical portion.
The sensor through hole is formed at a position of the bottom of the cap facing a part in the circumferential direction of the detected surface of the encoder.
The nut through hole is formed in the cap bottom.
The sensor mounting nut is directly fixed to the outer side in the axial direction of the cap bottom by press-fitting and fixing an axial inner end portion into the nut through hole .
The rubber member is integrally formed of rubber and vulcanized and bonded to the cap body, and includes a seal portion, a sensor holding portion, and a nut cover portion in a continuous state. ing.
Among these, the seal portion is elastically contacted with the inner peripheral surface of the outer ring over the entire circumference in a state of being vulcanized and bonded to the entire circumference of the axially inner end portion of the outer peripheral surface of the cap cylindrical portion. Yes.
The sensor holding portion includes a holding cylinder portion that covers the inner peripheral surface in a state of being vulcanized and bonded to the inner peripheral surface of the sensor through hole, and a holding bottom plate that closes an axial outer end opening of the holding cylinder portion. It is a bottomed cylindrical shape which consists of a part.
The nut cover portion covers the sensor mounting nut so that it is not exposed to the internal space where the encoder is installed.
In the sensor unit, a holder main body, which is a portion of the sensor holder that holds the sensor, is fitted into the holding cylinder portion, and the holder main body is brought into contact with an axial inner side surface of the holding bottom plate portion. In this state, the bolt is screwed to the sensor mounting nut and fixedly coupled to the axially inner side surface of the cap bottom .

Preferably, when carrying out the present invention, the axial position of the axially inner side surface of the holding bottom plate portion is set to be axially outer than the axially outer surface of the cap bottom portion, as in the invention described in claim 2. To do. In the case of carrying out the invention according to the second aspect, preferably, the axial position of the inner side surface in the axial direction of the holding bottom plate portion is set as the axially intermediate portion of the cap cylindrical portion.
Although not within the technical scope of the present invention, instead of press-fitting and fixing the inner end of the sensor mounting nut in the nut through hole formed in the cap bottom, the inner surface, forming a bottomed nut recess recessed axially outward, the sensor mounting nut, can also be configured so as to press-fitted into the inside of the nut recess.

According to the rolling bearing unit with a rotational speed detection device of the present invention having the above-described configuration, it is possible to realize a structure that can easily secure the positioning accuracy of the encoder and the sensor in the axial direction and can suppress the manufacturing cost.
That is, in the case of the present invention, the sensor unit is directly fixed to the cap. For this reason, it is possible to reduce the number of members existing between the encoder and the sensor as compared with the conventional structure described above. As a result, the positioning accuracy between these encoders and sensors can be made sufficiently high to improve the reliability of rotational speed detection.
Further, in the case of the present invention, the sensor unit can be supported with respect to the outer ring only by fixing (press-fitting) the cap to the inner end of the outer ring in the axial direction, thus simplifying the assembly process. it can. In addition, the processing cost can be reduced because the knuckle is not required to be processed.
Further, in the case of the present invention, the sensor detection portion is opposed to the detection surface of the encoder body via the holding bottom plate portion of the rubber sensor holding portion without passing through the cap bottom portion of the metal cap body. Yes. For this reason, the metal material of the cap body may be made of a magnetic material or a non-magnetic material. Therefore, if this cap body is made of a cold rolled steel sheet for deep drawing such as SPCE, which is inexpensive and easy to press, it is expensive and difficult to press, such as an austenitic stainless steel sheet. Compared with the case of using a nonmagnetic metal plate, the manufacturing cost can be reduced.
Further, when a non-magnetic metal plate is employed, even if the metal plate becomes magnetized by pressing, a process for removing magnetism from the metal plate is not required, and thus the manufacturing cost can be reduced.

The fragmentary sectional view which shows the rolling bearing unit with a rotational speed detection apparatus which shows an example of embodiment of this invention. Similarly, the figure which shows the assembly | attachment state of a sensor unit in the state seen from the axial direction inner side. The figure similar to FIG. 1 which shows one example of the reference example relevant to this invention . The half part sectional view which shows an example of the conventional structure of a rolling bearing unit with a rotational speed detection apparatus.

[1 Example Embodiment
1 and 2 show an example of an embodiment of the present invention. The feature of this example is that the structure of the cap 18a that closes the axially inner end opening of the outer ring 4 is devised. Since the configuration and operational effects of the other parts are basically the same as those of the above-described conventional structure, overlapping illustrations and explanations are omitted or simplified. The description will focus on the parts that were not explained.

  The rolling bearing unit 1a with a rotational speed detection device of this example supports a wheel which is a driven wheel rotatably with respect to a suspension device such as a knuckle 9 (see FIG. 4) and detects the rotational speed of this wheel. A hub 5 that is a rotating ring is rotatably supported via a plurality of rolling elements 6 on the inner diameter side of the outer ring 4 that is a stationary ring.

  The hub body 10 constituting the outer ring 4 and the hub 5 is made of medium carbon steel such as S53C, and at least the surface of each track 7a, 7b, 13a (see FIG. 4) is subjected to hardening treatment such as induction hardening. Has been. On the other hand, the inner ring 11 and the rolling elements 6 constituting the hub 5 are made of high carbon chrome bearing steel such as SUJ2, and are subjected to a hardening process by, for example, full quenching. The rolling elements 6 to be used are not limited to balls as shown in FIG. When the rolling bearing unit with a rotational speed detection device 1a of this example is used for an automobile having a heavy weight, a tapered roller can be used as the rolling element 6.

  An encoder 21 is fitted and fixed (press-fit) to the axially inner end (right end in FIG. 1) of the outer peripheral surface of the inner ring 11 constituting the hub 5. The encoder 21 includes a support ring 23 and an encoder body 24. Of these, the support ring 23 is formed in an annular shape with a substantially L-shaped cross section by pressing a ferritic stainless steel plate such as SUS430 or a cold rolled steel plate such as SPCC subjected to rust prevention treatment. Has been. The support ring 23 is a cylindrical fitting tube portion 31 and a circle that is bent in a radially outward direction from the axially inner end portion (right end portion in FIG. 1) of the fitting tube portion 31. It is comprised from the ring part 32. FIG. The encoder body 24 is formed in a ring shape by a permanent magnet such as a rubber magnet or a plastic magnet mixed with a magnetic material such as ferrite powder, and is magnetized in the axial direction and the direction of magnetization. These are changed alternately and at equal intervals in the circumferential direction. Then, with such an encoder body 24 attached to the inner surface in the axial direction of the annular portion 32, the inner surface in the axial direction (detected surface) of the encoder body 24 is set in the axial direction of the hub body 10. The caulking portion 12 formed at the end portion is positioned radially outward.

The cap 18 a attached to the inner end of the outer ring 4 in the axial direction includes a metal cap body 33, a sensor mounting nut 34, and a rubber member 35.
Of these, the cap body 33 has a bottomed cylindrical shape (cross-section) by pressing a cold-rolled steel sheet for deep drawing such as SPCE and a cold-rolled plated steel sheet for deep drawing such as SECE. The shape is a petri dish with a substantially U-shape. Such a cap main body 33 includes a cap cylindrical portion 36 and a cap bottom portion 37 that closes an axially inner end opening of the cap cylindrical portion 36. The cap body 33 can also be made of a metal plate made of a non-magnetic material such as an austenitic stainless steel plate or an aluminum alloy plate.

The outer peripheral surface of the outer half portion in the axial direction of the cap cylindrical portion 36 is formed in a cylindrical surface shape whose outer diameter does not change in the axial direction. On the other hand, the outer peripheral surface of the inner half portion in the axial direction of the cap cylindrical portion 36 is formed in a tapered surface shape that is inclined in a direction in which the outer diameter decreases as it goes inward in the axial direction.
In addition, a sensor through hole 38 having a rectangular shape when viewed from the axial direction is formed in a portion of the cap bottom portion 37 facing the detection surface of the encoder 21 (encoder main body 24) in the axial direction. . The shape of the inner surface of the sensor through-hole 38 has such a size that a holder cylinder portion 43 of the sensor holding portion 41, which will be described later, and a holder main body 26a constituting the sensor holder 25a of the sensor unit 22a can be arranged on the inner side. doing. Further, a nut through-hole 39 having a circular shape when viewed from the axial direction is formed in the central portion in the radial direction of the cap bottom portion 37. The inner diameter dimension of the nut through hole 39 has such a size that a small diameter portion of the sensor mounting nut 34 described below can be press-fitted and fixed.

  The sensor mounting nut 34 is a so-called press-fit nut that penetrates in the axial direction, and a small-diameter portion provided on the inner side surface in the axial direction is press-fitted into the through-hole 39 for nut from the outside in the axial direction of the cap bottom portion 37. It is fixed by the thing. The structure of the sensor mounting nut 34 is substantially the same as that of a general press-fit nut. Further, the sensor mounting nut 34 may have a structure that does not penetrate in the axial direction, that is, a cap nut shape.

The rubber member 35 which is a non-magnetic material is integrated with various rubbers such as acrylonitrile butadiene rubber (NBR) having a hardness of 60 to 75, natural rubber, styrene butadiene rubber, urethane rubber, silicone rubber, fluorine rubber, acrylic rubber and the like. And is vulcanized and bonded to the cap body 33 and includes a seal portion 40, a sensor holding portion 41, and a nut cover portion 42.
Of these, the seal portion 40 is annular, and is fixed by vulcanization adhesion over the entire circumference of the outer circumferential surface of the inner half portion of the cap cylindrical portion 36 in the axial direction. The outer diameter dimension of the seal portion 40 in the free state (the state shown in FIG. 1) while being fixed to the cap cylindrical portion 36 in this manner is larger than the inner diameter dimension of the inner peripheral surface of the inner end portion in the axial direction of the outer ring 4. Is also big.

  The sensor holding portion 41 is vulcanized and bonded in a state of covering the inner peripheral surface of the sensor through-hole 38, and the holding cylinder portion 43 having a rectangular shape as viewed from the axial direction, and the shaft of the holding cylinder portion 43 It is formed in a bottomed cylindrical shape including a rectangular plate-shaped holding bottom plate portion 44 formed so as to close the direction outer end opening. The inner peripheral surface of the holding cylinder portion 43 of the sensor holding portion 41 has such a size that a holder main body 26a constituting a sensor holder 25a of the sensor unit 22a described later can be disposed without a gap. Further, one circumferential position of the inner end portion in the axial direction of the holding cylinder portion 43 and one circumferential position of the inner end portion in the axial direction of the seal portion 40 are continuous by the first continuous portion 45. .

  The nut cover portion 42 covers the outer peripheral surface of the sensor mounting nut 34 fixed to the cap body 33 and the axial outer end surface (including the axial outer end opening) as described above. The nut cover portion 42 is formed in a bottomed cylindrical shape including a cylindrical portion 46 and a bottom plate portion 47 that closes the axially outer end opening of the cylindrical portion 46. Further, one circumferential position of the cylindrical portion 46 of the nut cover portion 42 and one circumferential position of the holding bottom plate portion 44 of the sensor holding portion 41 are continuously provided by the second continuous portion 48. Yes. Such a nut cover portion 42 is fixed to the outer surface in the axial direction of the cap bottom portion 37 and the sensor mounting nut 34 by vulcanization adhesion. In this way, the sensor mounting nut 34 is not exposed to the internal space 16 in which the encoder 21 is installed.

  The cap 18a having the above-described configuration uses a device composed of a pair of molds (upper mold and lower mold), and the sensor is mounted in a cavity defined between the molds. It can be made by pouring vulcanized molten rubber into the cavity in a state where the cap body 33 to which the nut 34 is fixed is disposed. When the cap 18a is manufactured in this manner, it is released into a vulcanization male screw material (not shown) corresponding to the bolt 29 in advance over the entire width of the female screw portion 49 of the sensor mounting nut 34. If an agent is applied and screwed together, the molten rubber can be prevented from flowing into the inner diameter side of the sensor mounting nut 34.

  The cap 18a having the configuration as described above is fitted directly into the outer ring 4 with the outer peripheral surface of the outer half of the axial direction of the cap cylindrical portion 36 in the inner peripheral surface of the inner end of the outer ring 4 in the axial direction (metal fitting). Assembled). Further, in such an assembled state, the seal portion 40 was compressed between the axial inner half outer peripheral surface of the cap cylindrical portion 36 and the axial inner end peripheral surface of the outer ring 4. It is pinched in a state. Further, the axially outer side surface of the holding bottom plate portion 44 of the sensor holding portion 41 is in close proximity to the detected surface of the encoder 21 via a predetermined axial gap (air gap).

In this example, the sensor unit 22a for detecting the rotational speed is supported and fixed to the cap 18a having the above-described configuration. The sensor unit 22a includes a sensor 51 and a sensor holder 25a. Among them, the sensor 51 has a magnetic detection element such as a Hall element or a magnetoresistive element installed in the detection unit, and changes an output signal in response to a change in characteristics of the detection surface of the encoder 21. The sensor holder 25a is formed by injection molding a synthetic resin such as polyamide resin, and includes a mounting plate portion 27a and a holder body 26a.
The mounting plate portion 27a is for fixing the holder body 26a to the cap 18a, and a holder side through hole 52 is formed at a position aligned with the nut through hole 39. . The inner peripheral surface of the holder-side through-hole 52 includes a small-diameter portion 53 formed near the outer end in the axial direction and a large-diameter portion 54 formed inward in the axial direction from the small-diameter portion 53. 55 is a stepped hole continuous.
The holder main body 26a holds the sensor 51 on the inner side, and is formed in a rectangular parallelepiped shape. Such a holder body 26a is fixed to a portion of the mounting plate portion 27a that faces the encoder 21 in the axial direction in a state where the sensor unit 22a is supported and fixed to the cap 18a. Yes.

In the sensor unit 22a as described above, the holder main body 26a is fitted into the holding cylinder 43 of the sensor holding portion 41 without rattling, and the holder main body 26a is held to the holding bottom plate portion 44 of the sensor holding portion 41. In this state, it is supported and fixed to the cap 18a (cap body 33) by a bolt 29. Specifically, in a state where the shaft portion of the bolt 29 is inserted into the small diameter portion 53 of the holder side through hole 52, the male screw portion 50 of the bolt 29 is fixed to the cap bottom portion 37. When the bolt 29 is tightened with the female screw portion 49 screwed together and the axially outer surface of the head of the bolt 29 in contact with the stepped portion 55, the cap 18a (cap body 33) is tightened. It is supported and fixed to it.
Since the holder main body 26a is engaged with the sensor holding portion 41 when the bolt 29 is tightened, the position of the sensor unit 22a is not shifted by the tightening torque of the bolt 29.

  Also in this example having the above-described configuration, the wheel fixed to the hub 5 can be rotatably supported with respect to the suspension device supporting the outer ring 4. Further, when the encoder 21 is rotated together with the hub 5 with the rotation of the wheel, the detection portion of the sensor 51 facing the detection surface of the encoder 21 via the holding bottom plate portion 44 of the sensor holding portion 41. The N pole and S pole existing on the detection surface of the encoder 21 alternately pass through the vicinity. As a result, the direction of the magnetic flux flowing in the magnetic detection element constituting the sensor 51 is alternately changed, and the characteristics of the magnetic detection element are alternately changed. Since the frequency at which the characteristic of the magnetic detection element changes in this way is proportional to the rotational speed of the hub 5, the ABS and TCS can be appropriately controlled by sending the output signal of the sensor 51 to a controller (not shown).

Particularly in the case of this example, it is possible to sufficiently secure the sealing performance by the cap 18a.
That is, in the case of this example, the holding bottom plate portion 44 of the sensor holding portion 41 is formed in the cap bottom portion 37 with the cap 18a assembled to the inner end portion in the axial direction of the outer ring 4. The axially outer end opening of the hole 38 is closed. For this reason, even if foreign matter such as water enters from a portion between the outer peripheral surface of the holder body 26a constituting the sensor holder 25a and the inner peripheral surface of the sensor holding portion 41, the foreign matter is transferred to each of the rolling elements 6. 6 and the inner space 16 in which the encoder 21 is installed can be prevented by the inner side surface in the axial direction of the holding bottom plate portion 44 of the sensor holding portion 41.

  Further, the outer peripheral surface of the cap cylindrical portion 36 of the cap main body 33 is directly metal-fitted to the inner peripheral surface of the inner end portion in the axial direction of the outer ring 4. For this reason, even when the use is continued, it is possible to prevent a gap or the like from being generated in the fitting portion. Further, the seal portion 40 is sandwiched between the outer circumferential surface of the inner half portion in the axial direction of the cap cylindrical portion 36 and the inner circumferential surface of the inner end portion in the axial direction of the outer ring 4 in a compressed state. For this reason, it can prevent that foreign materials, such as water, penetrate | invade into the said fitting part. Therefore, according to this example, the sealing performance by the cap 18a can be sufficiently ensured.

  The sensor unit 22a is directly fixed to the cap 18a. For this reason, it is possible to reduce the number of members existing between the encoder 21 and the sensor 51 as compared with the conventional structure described above. As a result, the positioning accuracy between the encoder 21 and the sensor 51 can be sufficiently increased. Therefore, according to this example, it is possible to improve the reliability of rotation speed detection. In the case of this example, the sensor unit 22a can be supported to the outer ring 4 only by fixing (press-fitting) the cap 18a to the inner end of the outer ring 4 in the axial direction. The assembly process can be simplified. In addition, the processing cost can be reduced because the knuckle is not required to be processed.

In the case of this example, the seal portion 40, the sensor holding portion 41, and the nut cover portion 42 are made of rubber and are coupled to the cap body 33 by vulcanization adhesion. For this reason, compared with the case where each of these members 34, 35, 44 is made of a synthetic resin, the connection between each of the members 34, 35, 44 and the cap body 33 is strengthened, and a gap is generated on the coupling surface. Can be prevented. Therefore, according to this example, the sealing performance by the cap 18a can be sufficiently ensured.
Further, when the holder main body 26a of the sensor holder 25a strongly contacts the holding bottom plate portion 44 of the sensor holding portion 41, the holding bottom plate portion 44 can be sufficiently elastically deformed. For this reason, it is possible to prevent the sensor holding portion 41 from being damaged such as a crack, and to sufficiently secure the sealing performance by the cap 18a.

In the case of this example, the sensor holder 25 a is disposed inside the sensor through hole 38 of the cap bottom portion 37. Therefore, as compared with the conventional structure described above, it can close the distance between the detection portion of the detection surface and the sensor 5 1 of the encoder 21. As a result, the sufficient amount of change in the output signal of the sensor 51, thereby improving the detection accuracy of the sensor 51.

Further, in the case of this example, the cap body 33 (cap bottom 37) does not exist between the detected surface of the encoder 21 (encoder body 24) and the detection part of the sensor 51. For this reason, the metal material of the cap body 33 may be made of a magnetic material or a non-magnetic material. Therefore, if this cap body 33 is made of a cold-rolled steel plate for deep drawing such as SPCE, which is inexpensive and easy to press, it is expensive and difficult to press like an austenitic stainless steel plate. Compared with the case of using a nonmagnetic metal plate, the manufacturing cost can be reduced.
Even when using a deep-drawn steel plate that has not been plated, such as SPCE, the cap 18a is covered with a rubber adhesive, so it has a certain degree of rust prevention performance, but is considered to have insufficient rust prevention performance. In such a case, the adhesive on the inner side surface in the axial direction of the cap bottom portion 37 can be peeled off to perform electrodeposition coating, or the material of the cap 18a can be replaced with a plated steel plate such as SECE.
In addition, when a metal plate made of a non-magnetic material such as an austenitic stainless steel plate is used, even if this metal plate becomes magnetized after press processing, a process for removing magnetism is not necessary, so the manufacturing cost Can be suppressed.

[ Example of reference example ]
FIG. 3 shows an example of a reference example related to the present invention. For speed sensing rolling bearing unit 1b in the present embodiment, the holding tube portion 43a of the sensor holding portion 41a is than holding tubular portion 43 of one example of the above-described embodiment (see FIG. 1), axial It is formed in a cylindrical shape with large dimensions. Specifically, in the case of this reference example , the axial outer end position (position of the holding bottom plate portion 44a) of the holding cylinder portion 43a of the sensor holding portion 41a is set to the axial center portion of the cap cylindrical portion 36a of the cap body 33a. It extends to the close part. Such a sensor holding portion 41a vulcanizes and bonds the axial inner end portion of the outer peripheral surface of the holding cylinder portion 43a to the inner peripheral surface of the sensor through-hole 38a, and the outer peripheral surface of the holding cylinder portion 43a. The outward flange portion 56 formed in the axially intermediate portion is fixed to the cap body 33a in a state where it is vulcanized and bonded to the axially outer surface of the cap bottom portion 37a.

In addition, a holder body 26b constituting the sensor holder 25b of the sensor unit 22b is formed in a cylindrical shape that is long in the axial direction. And the attachment board part 27b is being fixed to the axial direction intermediate part of this holder main body 26b.
In the case of this reference example, the bottom of the cap main body 33a of the cap bottom portion 37a on the inner side surface in the axial direction is recessed outward in the axial direction, and the shape viewed from the axial direction is a hexagonal shape. A nut recess 57 is formed. Then, the sensor mounting nut 34a, which is a hexagonal nut, is press-fitted into the nut recess 57, and the axially inner end of the nut recess 57 is plastically deformed (caulked) toward the sensor mounting nut 34a. Thus, the sensor mounting nut 34a is fixed to the cap bottom portion 37a.
For such present embodiment, nut covering portion 42 of the example of embodiment described above is not required. Therefore, the material of the rubber member 35a can be reduced, and the rubber member 35a (the seal portion 40 and the sensor holding portion 41a) can be easily formed. About another structure and an effect, it is substantially the same as that of the case of one example of embodiment mentioned above.

In carrying out the present invention, one example of the above-described embodiment and one example of the reference example can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Rolling bearing unit with a rotational speed detection apparatus 2 Rolling bearing unit 3 Rotational speed detection apparatus 4 Outer ring 5 Hub 6 Rolling body 7a, 7b Outer ring track 8 Stationary side flange 9 Knuckle 10 Hub body 11 Inner ring 12 Caulking part 13a, 13b Inner ring raceway 14 Rotating flange 15 Cage 16 Internal space 17 Seal ring 18, 18a Cap 19 Bottom plate part 20 Cylindrical part 21 Encoder 22, 22a, 22b Sensor unit 23 Support ring 24 Encoder body 25, 25a, 25b Sensor holder 26, 26a, 26b holder body 27, 27a, 27b mounting plate portion 28 sensor insertion hole 29 bolt 30 threaded hole 31 fitting tube 32 circular ring portion 33,33a cap body 34,34a sensor attachment nut 35,35a rubber member 36, 36a cap Cylindrical part 37, 37a Cap bottom part 38, 38a Sensor through hole 39 Nut through hole 40 Seal part 41, 41a Sensor holding part 42 Nut cover part 43, 43a Holding cylinder part 44, 44a Holding bottom plate part 45 First continuous part 46 Cylindrical part 47 Bottom plate part 48 Second continuous part 49 Female thread part 50 Male thread part 51 Sensor 52 Holder side through hole 53 Small diameter part 54 Large diameter part 55 Step part 56 Flange part 57 Nut recess

Claims (3)

An outer ring having a double-row outer ring raceway on the inner peripheral surface and not rotating during use;
The outer ring has a double-row inner ring raceway and is supported concentrically with the outer ring on the inner diameter side of the outer ring, and on the part of the outer circumferential surface that protrudes outward in the axial direction from the axial outer end of the outer ring. A hub provided with a rotation side flange for supporting the wheel;
Between the both outer ring raceways and the both inner ring raceways, a plurality of rolling elements provided so as to be freely rollable for each row,
An annular encoder that is formed by alternately changing the magnetic properties of the inner surface in the axial direction with respect to the circumferential direction, and is supported concentrically with the hub at the inner end in the axial direction of the hub;
A cap that is attached to the axially inner end of the outer ring and closes the axially inner end opening of the outer ring;
A sensor that changes the output signal in response to a change in the magnetic characteristics of the detected surface of the encoder while facing the detected surface of the encoder in the axial direction, and is supported by the cap while holding the sensor. A sensor unit comprising a sensor holder,
A rolling bearing unit with a rotational speed detection device comprising:
The cap includes a cap body, a sensor mounting nut, and a rubber member.
The cap body is made of metal and has a bottomed cylindrical shape. The cap cylindrical portion is fitted in and fixed to the inner end portion in the axial direction of the outer ring, and the inner end opening in the axial direction of the cap cylindrical portion. a cap bottom for closing the out of the cap bottom, having a circumferential portion facing the sensor through-holes formed at positions, the cap bottom nut through-hole formed in the detected face of the encoder Is,
The sensor mounting nut is directly fixed to the outer side in the axial direction of the bottom of the cap by press-fitting and fixing the inner end of the axial direction into the through hole for the nut ,
The rubber member is integrally formed of rubber and is vulcanized and bonded to the cap body, and includes a seal portion, a sensor holding portion, and a nut cover portion in a continuous state. The seal portion is elastically contacted with the inner peripheral surface of the outer ring over the entire circumference while being vulcanized and bonded to the entire circumference of the axially inner end portion of the outer peripheral surface of the cap cylindrical portion. The sensor holding portion is a holding cylinder portion that covers the inner peripheral surface in a state of being vulcanized and bonded to the inner peripheral surface of the sensor through hole, and a holding member that closes the axially outer end opening of the holding cylinder portion. It is a bottomed cylindrical shape composed of a bottom plate portion, and the nut cover portion covers the sensor mounting nut so that it is not exposed to the internal space where the encoder is installed,
In the sensor unit, a holder main body, which is a portion of the sensor holder that holds the sensor, is fitted into the holding cylinder portion, and the holder main body is brought into contact with an inner side surface in the axial direction of the holding bottom plate portion. In the state, it is directly coupled and fixed to the inner surface in the axial direction of the bottom of the cap by a bolt screwed into the sensor mounting nut.
A rolling bearing unit with a rotational speed detector. The rolling bearing unit with a rotational speed detection device according to claim 1, wherein an axial position of an inner side surface in the axial direction of the holding bottom plate portion is an outer side in the axial direction than an outer side surface in the axial direction of the cap bottom portion. The rolling bearing unit with a rotational speed detection device according to claim 2, wherein an axial position of an inner side surface in the axial direction of the holding bottom plate portion is an intermediate portion in the axial direction of the cap cylindrical portion.

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