JP2015209905A - Rolling bearing unit with rotation speed detector device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure in which a cap fixed to an axial inner end part of an outer ring is prevented from being pushed toward an axial outer direction, and an axial position of the cap can be accurately restricted and an axial position setting accuracy between an encoder and a sensor can be easily assured.SOLUTION: A sensor unit 22a is fixed to a cap 18a under a state in which a holder main body 26a of a sensor unit 22a is directly inserted inside a sensor holding part 37 arranged at the first holding part 42 made of synthetic resin. In addition, the cap 18a is fixed to the outer ring 4 under a state in which a core bottom part 38 is positioned at an axial outside part. Then, under this fixed state, an axial outer surface of a core flange part 40 and an axial inner end surface of the outer ring 4 are axially abutted to each other through an annular covering 45, an axial position setting of the cap 18a in respect to the outer ring 4 is attained and at the same time, a detecting part of a sensor 50 is oppositely faced against the detected surface of the encoder 21 through the core bottom part 38.

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. 5 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. 5, since the rolling bearing unit 2 for a driven wheel (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 an attachment flange portion 27 that is fixed to the knuckle 9. Such a sensor unit 22 has a male thread portion of a bolt 29 inserted through a through hole formed in the mounting flange 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. When the encoder body 24 rotates together with the hub 5 in this state, the S pole and the N pole existing on the detected surface alternately pass through the vicinity of the detection portion of the sensor 22, and the output of the sensor 22 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. 5 as described above, the permanent magnet encoder body 24 and the external space are separated by the cap 18 made of a nonmagnetic 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.

  First, in the case of the conventional structure, since there is no means for restricting the displacement of the cap 18 in the axial direction outside, it may be difficult to accurately regulate the axial position of the cap 18. For example, after restricting the axial position of the cap 18 to the position shown in FIG. 5, the cap 18 is moved to the encoder by pressing the detection portion of the sensor strongly against the axial inner side surface (outer surface) of the bottom plate portion 19. There is a possibility of pushing into the 21 side (the outside in the axial direction). When the pushing amount of the cap 18 increases, the axially outer surface (inner surface) of the bottom plate portion 19 collides with the detected surface of the encoder main body 24 to damage the detected surface, or the encoder main body. The detection gap (air gap) between the detected surface of 24 and the detection part of the sensor 22 may be inappropriate, resulting in a sensing error. Furthermore, a part of the support ring 23 constituting the encoder 21 comes into contact with the rolling surfaces of the rolling elements 6 in the inner row in the axial direction and the cage 15 that holds these rolling elements 6, thereby rolling bearing units. The bearing function of 2 may be impaired.

  Further, 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.

JP 2000-249138 A

  In view of the circumstances as described above, the present invention prevents the cap that closes the axial inner end opening of the internal space in which the encoder is installed from being pushed into the encoder side, thereby accurately determining the axial position of the cap. The invention has been invented to realize a structure that can be well regulated and that can easily secure the positioning accuracy of the encoder and sensor in the axial direction.

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 characteristics of the detected surface of the encoder while facing the detected surface of the encoder.
The sensor holder holds the sensor and is supported by a portion of the cap that faces the encoder in the axial direction.

In particular, in the case of the rolling bearing unit with a rotational speed detection device according to the present invention, the cap has a fitting mandrel, a sensor mounting nut, and a sensor holding portion.
Of these, the fitting core is made entirely of a non-magnetic material, and includes a cored bar bottom, a cored bar cylindrical part, and a cored bar flange.
Among these, the cored bar cylindrical part is provided in a state of being bent at a right angle inward in the axial direction from the radially outer end of the cored bar bottom.
Further, the core metal flange portion is provided in a state of being bent radially outward from the axially inner end portion of the core metal cylindrical portion.
The sensor mounting nut is supported by the fitting core and is screwed with a bolt for fixing the sensor unit to the cap.
The sensor holding portion is provided in a portion of the cap facing the encoder in the axial direction, and at least the sensor holding portion is engaged with the axial outer end portion of a holder main body constituting the sensor holder. This is for positioning with the encoder.
In the cap as described above, the core metal cylindrical portion is fitted and fixed to the inner end portion in the axial direction of the outer ring, so that the fitting core metal is opened in the axial direction, It is assembled | attached to the axial direction inner end part.
And in this assembled state, the axial outer surface of the cored bar flange portion and the axial inner end surface of the outer ring are directly or indirectly abutted against each other in the axial direction. Positioning in the axial direction with respect to the outer ring is achieved, and the detection unit of the sensor faces the detection surface of the encoder through the cored bar bottom.

When the present invention is implemented, specifically, for example, as in the invention described in claim 2, the sensor holding portion is made of synthetic resin and fixed to the inner side surface in the axial direction of the bottom portion of the cored bar. Provided in the first holding part.
Alternatively, as in the invention described in claim 3, the sensor holding part is formed directly on the inner side surface in the axial direction of the bottom part of the cored bar. In this case, the sensor holding part can be constituted by a concave part or a convex part (for example, a circular bead) formed on the inner side surface in the axial direction of the bottom part of the metal core.

Specifically, when carrying out the present invention, as in the invention described in claim 4, the sensor mounting nut is made of synthetic resin and fixed to the axially inner side surface of the bottom part of the cored bar. The holding part is molded in an open state on the inner side surface in the axial direction of the first holding part.
Alternatively, as in the invention described in claim 5, the radially inner end portion of the fitting core bar is continuous with the cylindrical core metal portion, and the radially outer end portion is an axial inner end surface of the outer ring. A cored bar arm portion that is located radially outward from the radially outer end portion is provided. Then, the sensor mounting nut is fixed to the core metal arm portion.

According to the rolling bearing unit with a rotational speed detection device of the present invention having the above-described configuration, the cap that closes the axial inner end opening of the internal space in which the encoder is installed can be prevented from being pushed into the encoder side. The position of the cap in the axial direction can be regulated with high accuracy, and a structure in which the positioning accuracy of the encoder and the sensor in the axial direction can be easily secured can be realized.
That is, in the case of the present invention, it is possible to position the cap in the axial direction with respect to the outer ring by using the axially outer surface of the cored bar flange formed on the fitting cored bar constituting the cap. For this reason, even when the cap is pressed outward in the axial direction, the cap can be prevented from being pushed into the encoder side, and the axial position of the cap can be accurately regulated. Therefore, in the case of the present invention, the axial outer surface of the cap can be prevented from colliding with the detected surface of the encoder, and the detected surface can be prevented from being damaged. It is possible to prevent the value of the detection gap between the sensor and the detection unit from becoming inappropriate. Furthermore, since a part of the encoder can be prevented from coming into contact with the rolling elements constituting the rolling bearing unit, the bearing performance of the rolling bearing unit can be prevented from being lowered.

In 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 the encoder and the sensor can be sufficiently increased. As a result, according to the present invention, it is possible to ensure the reliability for detecting the rotational speed.
Furthermore, in the case of the present invention, the sensor unit can be supported with respect to the outer ring simply by fixing (press-fitting) the cap to the inner end of the outer ring in the axial direction. The process can be simplified. In addition, the processing cost can be reduced because the knuckle is not required to be processed.

The fragmentary sectional view which shows the rolling bearing unit with a rotational speed detection apparatus which shows the 1st example of embodiment of this invention. Similarly, the figure which looked at the sensor holding | maintenance part and nut holding | maintenance part of the cover part from the axial direction inner side. The figure similar to FIG. 1 which shows the 2nd example. The figure similar to FIG. 1 which shows the 3rd example. The half part sectional view which shows an example of the conventional structure of a rolling bearing unit with a rotational speed detection apparatus.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1, 2, and 4. FIG. 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. explain.

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

  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. 5) is subjected to hardening treatment such as induction hardening. Has been. On the other hand, the inner ring 11 and the rolling elements 6 and 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, continuous quenching. The rolling elements 6 to be used are not limited to the 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. Further, the support ring 23 is provided in a state of being bent in a radially outward direction from a cylindrical fitting tube portion 31 and an axially outer end portion (left end portion in FIG. 1) of the fitting tube portion 31. It is comprised from the collar part 32 and the annular ring part 33 provided in the state bent from the axial direction inner end part of the said fitting cylinder part 31 to radial inside. The fitting tube portion 31 is provided in the outer half portion in the axial direction, and is provided on the inner half portion in the axial direction and a small-diameter portion directly fitted on the inner end portion in the axial direction of the inner ring 11. And a taper portion that is inclined in a direction in which the outer diameter dimension increases as it goes to. 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 ring portion 33, 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 18a attached to the inner end of the outer ring 4 in the axial direction includes a fitting core 34 that is a main body of the cap, a cover 35 that is made of synthetic resin and covers the fitting core 34, and this cover. And a sensor mounting nut 36 disposed (inserted) inside the portion 35.
Of these, the fitting core 34 is formed into a substantially bottomed cylindrical shape that is opened inward in the axial direction by pressing a nonmagnetic metal plate such as an austenitic stainless steel plate or an aluminum alloy plate. ing. Such a fitting metal core 34 is composed of a disk-shaped metal core bottom portion 38 provided at the axially outer end portion of the cap 18a, a metal core cylindrical portion 39, and a metal core flange portion 40. .

Among these, the cored bar cylindrical part 39 is formed in a state of being bent at a right angle inward in the axial direction from the radial outer end part of the cored bar bottom part 38.
The cored bar flange 40 is formed in an annular shape that is bent at a right angle from the axially inner end of the cored bar cylindrical part 39 radially outward. Further, at a plurality of positions in the circumferential direction of the radially outer end edge of the cored bar flange portion 40, non-rotating notches 41, 41 are provided on both axial side surfaces and the radially outer end edge of the cored bar flange portion 40. It is formed in an open state. Each of the non-rotating cutouts 41, 41 is formed by, for example, cutting a part of the core metal flange portion 40 in the circumferential direction into a non-circular shape or bending (crushing) it inward in the radial direction. Form.

The cover 35 is made by, for example, injection molding a polyamide resin mixed material in which glass fiber is appropriately added to polyamide 66 resin. If an amorphous aromatic polyamide resin (modified polyamide 6T / 6I) and a low water-absorbing aliphatic polyamide resin (polyamide 11 resin, polyamide 12 resin, polyamide 610 resin, polyamide 612 resin) are appropriately added to the polyamide resin, the water resistance becomes higher. Can be improved.
The cover portion 35 thus manufactured covers the outer surface of the fitting core bar 34 (the portion excluding the axially outer side surface of the cored bar bottom portion 38 and the outer peripheral surface of the axially outer half portion of the cored bar cylindrical portion 39). In this state, it is coupled to the fitting core metal 34 and has a first holding portion 42 and an annular cover portion 45 provided in a continuous state.

Among these, the first holding portion 42 covers the axial inner side surface of the core metal bottom portion 38, the entire inner peripheral surface of the core metal cylindrical portion 39, and the axial inner side surface of the core metal flange portion 40. Is formed. A thick part 43 that bulges inward in the axial direction than the other part (having a larger axial thickness dimension) is provided in a part of the first holding part 42 in the circumferential direction. .
In addition, a holder main body 26a of a sensor unit 22a, which will be described later, is held inside a portion of the thick portion 43 that faces the detection surface of the encoder 21 (encoder main body 24) in the assembled state. A sensor holding part 37 is formed for this purpose. The sensor holding portion 37 is formed in a state where the inner end in the axial direction opens on the inner end surface in the axial direction of the thick portion 43 and the outer end in the axial direction opens on the outer end surface in the axial direction of the thick portion 43. Yes. Also, the axially outer end opening of the sensor holding part 37 has the encoder 21 (encoder main body) of the cored bar bottom 38 in a state where the cover part 35 and the fitting cored bar 34 are fixed. 24) is blocked by a portion facing the detected surface in the axial direction.

  Further, a nut holding portion 44 for holding the sensor mounting nut 36 is provided inside the thick portion 43 at a position shifted radially inward from the sensor holding portion 37. Yes. Such a nut holding portion 44 is also formed in such a manner that the inner end in the axial direction opens on the inner end surface in the axial direction of the thick portion 43 and the outer end in the axial direction opens on the outer end surface in the axial direction of the thick portion 43. Has been. The nut holding portion 44 is formed by insert-molding the sensor mounting nut 36 into the cover portion 35.

Further, the annular cover 45 is an inner half in the axial direction among the radially outer end edge of the cored bar flange 40, the axially outer side surface of the cored bar flange 40, and the outer peripheral surface of the cored bar cylindrical part 39. It is fixed to the fitting mandrel 34 so as to cover the part.
On the inner circumferential surface of the annular outer end portion 45 of this kind in the axial direction outer end portion, a concave groove 46 having a rectangular cross section that is opened outward in the axial direction and radially inward is formed over the entire circumference. Further, of the axial outer end surface of the annular cover 45, the outer diameter side portion of the concave groove 46 with respect to the axial outer end opening abuts against the axial inner end surface of the outer ring 4. Is formed.

  The cover portion 35 having the above-described configuration is connected and fixed to the fitting core metal 34, and both axial side surfaces of the core metal flange portion 40 and the cover portion 35 are related with respect to the axial direction. By combining, the relative displacement in the axial direction between the fitting cored bar 34 and the covering portion 35 is prevented. Further, both circumferential sides of the rotation stopper notches 41 and 41 of the core metal flange portion 40 and portions of the cover portion 35 filled inside the rotation stopper notches 41 and 41 are provided. By engaging in the circumferential direction, relative rotation between the fitting core 34 and the cover 35 is prevented.

  The sensor mounting nut 36 has a cylindrical shape with a bottom, and an internal thread portion 47 is formed on the inner peripheral surface. Wrapped grooves 48a and 48b are formed. The sensor mounting nut 36 is embedded (internally fitted) in the nut holding portion 44. In the case of this example, the sensor mounting nut 36 has a structure that does not penetrate in the axial direction (cap nut), but a structure that penetrates in the axial direction can also be adopted.

Then, in a state where the sensor mounting nut 36 is embedded in the cover portion 35, both side surfaces in the axial direction of the concave grooves 48 a and 48 b and the inner side of the concave grooves 48 a and 48 b of the cover portion 35. And the portion filled with the shaft are engaged in the axial direction to prevent relative displacement of the sensor mounting nut 36 in the axial direction with respect to the cover portion 35.
The inner end surface of the sensor mounting nut 36 in the axial direction is located on the same virtual plane as the inner surface of the thick portion 43 in the axial direction, and the female screw portion 47 is connected to the inner surface of the thick portion 43 in the axial direction. Is open.

  Further, the method of fixing the sensor mounting nut 36 to the cover portion 35 is not limited to insert molding, and a portion corresponding to the nut holding portion 44 of the cover portion 35 is locked to the inner peripheral surface of the cover portion 35 in the axial direction. The nut insertion hole in which the concave groove is formed is formed, and the sensor mounting nut having an axially long locking protrusion on the outer peripheral surface is connected to the phase of the locking protrusion and the locking groove. Or a nut having a long ridge in the axial direction, such as serrations, is press-fitted into the nut insertion hole in which a groove or the like is not formed on the inner peripheral surface. A groove can be formed on the inner peripheral surface of the nut insertion hole by the strip to lock the nut. When such a configuration is adopted, the nut insertion hole may have a structure of a through hole or a bottomed hole.

  The cap 18a having the above-described configuration includes, for example, a pair of molds (upper mold and lower mold) having a mold insertion portion having an outer peripheral surface shape that matches the inner peripheral surface shape of the sensor holding portion 37. It can be formed by injection molding (axial draw molding) in a state where the sensor mounting nut 36 and the fitting core metal 34 are disposed in a cavity defined between the two molds. .

  The cap 18a corresponds to the annular seal member described in the claims in a portion of the outer peripheral surface of the cored bar cylindrical portion 39 that overlaps the concave groove 46 of the annular cover portion 45 in the radial direction. The outer peripheral surface of the axial outer half of the cored bar cylindrical portion 39 is the inner peripheral surface of the outer ring 4 in the axial direction while the rubber O-ring 49 is attached (externally fitted). The outer ring 4 is assembled to the outer ring 4 by directly fitting (metal fitting) to the outer ring 4 and abutting the outer end surface in the axial direction of the annular cover 45 against the inner end surface in the axial direction of the outer ring 4. In this assembled state, the outer surface in the axial direction of the core metal bottom portion 38 is in close proximity to the detected surface of the encoder 21 via a predetermined axial gap (air gap).

  Further, the O-ring 49 is clamped in an axially compressed state between the axial side surface of the concave groove 46 and the axial inner end surface of the outer ring 4 in the assembled state as described above. Is done. For this reason, even when foreign matter such as water enters from the abutting portion between the axial outer end surface of the annular cover 45 and the axial inner end surface of the outer ring 4, such foreign matter is caused by the O-ring 49. Thus, it is possible to effectively prevent the metal fitting portion between the outer peripheral surface of the core metal cylindrical portion 39 and the inner peripheral surface of the outer ring 4 in the axial direction from being reached.

  In the case of this example, the end of the coupling surface (the boundary surface between the members 35, 34) of the cover portion 35 and the fitting metal core 34 of the cap 18a is the rolling elements 6, 6 and the space 16 in which the encoder 21 is installed. That is, the coupling surface is not provided in a state of being continuous (exposed) directly to the space 16. For this reason, for example, foreign matter such as water entering from a portion between an inner peripheral surface of the sensor holding portion 37 and an outer peripheral surface of a holder main body 26a of the sensor holder 25a, which will be described later, is inserted into the cover portion 35 and the fitting portion. It does not penetrate into the space 16 through the gap generated on the coupling surface with the cored bar 34. In the case of this example, the end of the coupling surface is located at the radially inner end of the side surface in the axial direction of the groove 46. For this reason, even if foreign matter such as water enters through the gap generated in the coupling surface between the cover portion 35 and the fitting core 34 to the position, the foreign matter is caused by the O-ring 49. Intrusion into the space 16 can be prevented.

  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 50 and a sensor holder 25a. Among them, the sensor 50 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. The sensor holder 25a holds the sensor 50 at the front end (axially outer end) and has the same inner diameter as the sensor holding portion 37 or A holder main body 26a having a slightly smaller outer diameter, and a mounting flange 27a provided at the base end of the holder main body 26a for fixing to the cap 18a. Such a sensor unit 22a has a male screw of a bolt 53 inserted through a sleeve 52 fitted in a through hole 51 formed in the mounting flange portion 27a in a state where the holder main body 26a is directly inserted into the sensor holding portion 37. The part 54 is fixed to the cap 18a (first holding part 42) by screwing into the female thread part 47 of the sensor mounting nut 36.

  Further, in the state where the sensor unit 22a is supported and fixed to the cap 18a, the front end surface (axially outer end surface) of the holder body 26a and the axially inner side surface of the cored bar bottom 38 constituting the fitting cored bar 34. Is in the state of facing or abutting through a minute gap in the axial direction. In such a state, the sensor 50 (the detecting portion thereof) held at the distal end portion of the holder body 26 a faces the detected surface of the encoder 21 through the core metal bottom portion 38.

  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. When the encoder 21 is rotated together with the hub 5 with the rotation of the wheel, the detecting portion of the sensor 50 facing the detected surface of the encoder 21 through the cored bar bottom 38 of the fitting cored bar 34. N poles and S poles existing on the detected surface of the encoder 21 alternately pass in the vicinity of. As a result, the direction of the magnetic flux flowing in the magnetic detection element constituting the sensor 50 changes alternately, and the characteristics of the magnetic detection element change alternately. Since the frequency at which the characteristics of the magnetic detection element change 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 50 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 axial inner side surface of the core metal bottom portion 38 is formed on the first holding portion 42 in a state where the cap 18a is assembled to the inner end portion of the outer ring 4 in the axial direction. The axially outer end opening of the sensor holding part 37 is blocked. For this reason, foreign matter such as water has entered the axial outer end (back) 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 37. Even in this case, this foreign matter can be prevented from entering the space 16 in which the rolling elements 6 and 6 and the encoder 21 are installed by the inner side surface in the axial direction of the cored bar bottom 38.

  In the case of this example, the end portion of the coupling surface (the boundary surface between the members 35, 34) between the cover portion 35 and the fitting metal core 34 of the cap 18 a exists in the space 16. do not do. That is, even when a gap is formed between the holder main body 26a fitted in the sensor holding portion 37 provided in the cover portion 35, which causes a problem in the case of the above-described conventional structure, the gap Does not lead to the space 16. For this reason, foreign matter such as water does not enter the space 16 through the gap formed on the coupling surface. Therefore, according to the present invention, sufficient sealing performance by the cap 18a can be secured.

In the case of this example, a cored bar flange portion 40 is formed on the fitting cored bar 34, and both side surfaces in the axial direction of the flange portion 40 are engaged with the cover portion 35 in the axial direction. For this reason, relative displacement in the axial direction between the fitting cored bar 34 and the covering portion 35 can be prevented.
Further, the circumferentially opposite side surfaces of the respective non-rotating notches 41, 41 of the core metal flange portion 40, and portions of the covering portion 35 filled in these non-rotating notches 41, 41, Engage in the circumferential direction. For this reason, relative rotation of the fitting cored bar 34 and the cover part 35 can be prevented.
In addition, the operation of press-fitting the cap 18a into the outer ring 4 is performed by using the axial inner end surface of the portion of the first holding portion 42 existing in the axial direction of the core metal flange portion 40 as an axis. This can be done by pressing outward. For this reason, this axially outward pressing force can be stably transmitted to the cored bar cylindrical part 39 via the cored bar flange part 40.

  Further, in the state where the cap 18 a is assembled to the outer ring 4, the axially outer side surface of the cored bar flange portion 40 of the fitting cored bar 34 and the axially inner end surface of the outer ring 4 are the annular cover part. 45 is engaged in the axial direction (the cored bar flange portion 40 and the inner end surface in the axial direction of the outer ring 4 are overlapped in the axial direction). For this reason, even if the cap 18a is pressed outward in the axial direction, the cap 18a can be prevented from being pushed into the encoder 21 side. As a result, the axial position of the cap 18a can be regulated with high accuracy. Therefore, in the case of this example, it is possible to prevent the outer surface in the axial direction of the cap 18a from colliding with the detected surface of the encoder 21, and to prevent the detected surface from being damaged. It is also possible to prevent the detection gap value between the surface and the detection unit of the sensor 50 from becoming inappropriate. Furthermore, since a part of the encoder 21 can be prevented from coming into contact with the rolling elements 6, 6 and the like arranged in the inner row in the axial direction, it is possible to prevent the bearing performance of the rolling bearing unit 1a from deteriorating. .

  Further, the outer peripheral surface of the core metal cylindrical portion 39 of the fitting core metal 34 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. Therefore, according to this example, the sealing performance by the cap 18a can be sufficiently ensured. It is also possible to easily ensure a constant gap in the axial direction between the sensor 50 and the encoder 21 over a long period of time.

  Further, the O-ring 49 is externally fitted to a portion of the outer peripheral surface of the cored bar cylindrical portion 39 that overlaps the concave groove 46 of the annular cover portion 45 in the radial direction. For this reason, it penetrate | invades from the clearance gap which arose between the axial direction inner end surface of the said outer ring | wheel 4 and the axial direction outer end surface of the said annular cover part 45, and the joint surface of the said cover part 35 and the said fitting metal core 34. It is possible to effectively prevent foreign substances such as water from entering the fitting portion between the outer peripheral surface of the core metal cylindrical portion 39 and the inner peripheral surface of the inner end portion in the axial direction of the outer ring 4.

  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 50 as compared with the conventional structure described above. As a result, the positioning accuracy between the encoder 21 and the sensor 50 can be sufficiently increased. Therefore, according to this example, it is possible to secure reliability for detecting the rotational speed. 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.

Further, in the case of this example, the fitting core metal 34 is in a state where the core metal bottom portion 38 is positioned axially outward from the core metal cylindrical portion 39 with respect to the outer ring 4 (inward in the axial direction). In an open state), the inner fitting is fixed. Accordingly, when the cored bar cylindrical part 39 is fitted and fixed to the inner peripheral surface of the inner end part in the axial direction of the outer ring 4, the R part existing in the continuous part of the cored bar cylindrical part 39 and the cored bar bottom part 38 and The thin part existing in the vicinity of the R part can be used as a guide. For this reason, the fitting metal core 34 can be fitted and fixed to the outer ring 4 without chamfering or deburring the axially inner end of the inner peripheral surface of the outer ring 4.
In addition, the continuous part of the cored bar cylindrical part 39 and the cored bar bottom part 38 can be formed in an inclined shape (partial conical shape) in which the outer diameter dimension decreases as it goes outward in the axial direction. Thus, if the shape of the continuous portion is inclined, the guide function of the continuous portion is improved, and the press-fitting work to the outer ring 4 can be facilitated. Further, since the continuous portion of the core metal cylindrical portion 39 and the core metal bottom portion 38 is inclined, the processing of the continuous portion becomes relatively easy (the degree of processing becomes low). The fitting cored bar 34 can be prevented from becoming magnetized.

[Second Example of Embodiment]
FIG. 3 shows a second example of an embodiment of the present invention corresponding to claims 1, 2, and 5. In the case of the rolling bearing unit 1b with the rotational speed detection device of this example, the fitting cored bar 34a constituting the cap 18b includes a cored bar bottom portion 38, a cored bar cylindrical portion 39, a cored bar flange portion 40a, a cored bar. And a gold arm portion 55. The structure of the cored bar bottom 38 and the cored bar cylindrical part 39 is substantially the same as the fitting cored bar 34 of the first example of the embodiment described above.

Further, the cored bar flange portion 40a is provided with a non-rotating notch 41 at a plurality of positions in the circumferential direction of the outer peripheral edge, like the cored bar flange portion 40 of the fitting cored bar 34 of the first example of the embodiment. 41 is formed. Further, in the case of this example, cut from the radially outer end edge to the radially inner end edge at one position of the cored bar flange portion 40a that is circumferentially disengaged from the non-rotating notches 41, 41. The discontinuous part (illustration omitted) is provided in the missing state.
Further, in the axially inner end portion of the cored bar cylindrical portion 39, the axially inner end portion of the cored bar cylindrical portion 39 is located at a position aligned with the discontinuous portion with respect to the circumferential direction. An axial extension 56 is formed in a state of extending in the direction.

  The cored bar arm portion 55 is provided in a state of being bent radially outward from the axially inner end portion of the axially extending portion 56. Such a core metal arm portion 55 has an outer end portion in the radial direction positioned more radially outward than an outer end portion in the axial direction of the inner end surface of the outer ring 4 in the axial direction. A portion of the core metal arm 55 that is positioned radially outward from the radial outer end of the axial inner end surface of the outer ring 4 penetrates the core arm 55 in the axial direction. A through-hole 57 is formed.

  Further, in the case of this example, a synthetic resin cylinder is formed on a portion of the inner side surface in the axial direction of the core metal bottom portion 38 that is opposed to the detected surface of the encoder 21 (encoder body 24) in the axial direction in the assembled state. A first holding portion 42a having a shape is fixed. In the case of this example, the inner peripheral surface of the first holding portion 42a constitutes a sensor holding portion 37a for holding the holder main body 26a of the sensor unit 22a. In the case of this example, of the axially inner side surface of the cored bar bottom 38, the part covered with the first holding part 42a, the radially outer end of the cored bar bottom 38 and the cored bar cylindrical part No synthetic resin portion exists in the portion excluding the continuous portion with the axially outer end portion 39, and the core metal bottom portion 38 is exposed to the outside.

In the case of this example, the second holding portion 58 is fixed to the outer surface in the axial direction of the core metal arm portion 55. The radially inner end portion of the second holding portion 58 is continuous with the outer peripheral surface of the annular covering portion 45 fixed to the inner half portion in the axial direction of the outer peripheral surface of the core metal cylindrical portion 39.
The second holding portion 58 is formed with a nut holding portion 44a for holding the sensor mounting nut 36 inside. Such a nut holding portion 44a is formed in a bottomed cylindrical shape whose inner end in the axial direction opens on the inner end surface in the axial direction of the second holding portion 58 and whose outer end in the axial direction does not open.
The nut holding portion 44a is formed by insert-molding the sensor mounting nut 36 into the second holding portion 58. The structure of the sensor mounting nut 36 is substantially the same as the structure of the first example of the embodiment.

  Also in this example, a sensor unit 22a for detecting the rotational speed is supported and fixed to the cap 18b. In the case of this example, the sensor unit 22a is supported and fixed to the cap 18b in a state where the sensor unit 22a is rotated by 180 ° compared to the case of the first example of the embodiment. The structure of the sensor 50 and the sensor holder 25a constituting such a sensor unit 22a is the same as that of the first example of the above embodiment. In the sensor unit 22a as described above, the sleeve 52 and the metal core arm portion fitted in the through hole 51 formed in the mounting flange portion 27a in a state where the holder main body 26a is directly inserted into the sensor holding portion 37a. The male threaded portion 54 of the bolt 53 inserted through the through hole 57 of the 55 is fixed to the cap 18a by screwing into the female threaded portion 47 of the sensor mounting nut 36. In such a fixed state, the core metal arm portion 55 is sandwiched between the head portion (mounting flange portion 27a) of the bolt 53 and the sensor mounting nut 36.

  In the case of this example having the above-described configuration, the sensor mounting nut 36 is provided radially outward from the outer peripheral surface of the inner end portion in the axial direction of the outer ring 4. For this reason, the freedom degree of the design regarding the axial direction dimension of the said sensor unit 22a can be improved. Incidentally, the rolling bearing unit 1b with the rotational speed detecting device of this example is located at one position in the circumferential direction of the inner peripheral surface of the mounting portion 59 of the knuckle 9 (see FIG. 5) and radially outward from the inner peripheral surface. The present invention can be applied to a structure in which a recessed portion that is recessed is formed. Further, the present invention is effective when applied to a structure in which the diameter of the bottom part of the metal core is small and it is difficult to mold the sensor mounting nut 36 on the first holding part 42 as in the first example of the embodiment described above. Can do. About another structure and an effect, it is substantially the same as the case of the 1st example of embodiment mentioned above.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention corresponding to the first, third, and fifth aspects. In the case of the rolling bearing unit 1c with the rotational speed detection device of this example, the synthetic resin portions (the first holding portions 42 and 42a and the second holding portion 58 as in the first and second examples of the embodiment described above). , And the annular cover 45) is not provided.

  The fitting cored bar 34b constituting the cap 18c of the present example is a part of the inner surface in the axial direction of the cored bar bottom 38a that faces the detected surface of the encoder 21 (encoder main body 24) in the axial direction in the assembled state. A sensor holding recess 60 that is recessed outward in the axial direction is formed at one position in the circumferential direction. In the case of this example, the sensor holding recess 60 corresponds to a sensor holding portion in the claims. The inner diameter dimension of the sensor holding recess 60 is slightly larger than the outer diameter dimension of the holder main body 26a constituting the sensor unit 22a near the outer end in the axial direction. The depth of the sensor holding recess can be made deeper or shallower than the sensor holding recess 60 of this example.

  Further, unlike the cored bar flange part 40 of the fitting cored bar 34 of the first example of the embodiment described above, the cored bar flange part 40b is not formed with a rotation stop notch 41 on the outer peripheral edge. Further, in the case of this example, the cored bar arm portion 55a is provided at one position in the circumferential direction on the outer peripheral edge of the cored bar flange 40b in a state extending radially outward from the outer peripheral edge. It has been. Such a cored bar arm portion 55 a has a radially outer end portion located radially outward from a radially outer end portion of the axially inner end surface of the outer ring 4. Further, a portion of the core metal arm portion 55a that is positioned radially outward from the radial outer end portion of the inner end surface of the outer ring 4 in the axial direction penetrates the core metal arm portion 55a in the axial direction. A through-hole 57a is formed.

  A sensor mounting nut 36a is coupled and fixed to the axially outer opening of the through hole 57a. The sensor mounting nut 36a is a so-called press-fit nut that penetrates in the axial direction, and is fixed by press-fitting a small diameter portion provided on the inner end face in the axial direction into the through hole 57a from the outside in the axial direction. . The structure of the sensor mounting nut 36a is substantially the same as that of a general press-fit nut.

  In the case of this example as described above, the sensor unit 22a for detecting the rotational speed is supported and fixed to the cap 18c. In the case of this example, the assembled state of the sensor unit 22a with respect to the cap 18c is substantially the same as in the second example of the embodiment described above. Also in this example, the sensor unit 22a as described above is formed on the mounting flange portion 27a in a state in which the portion near the tip (the portion near the outer end in the axial direction) of the holder body 26a is inserted into the sensor holding recess 60. The cap 52 is formed by screwing the sleeve 52 fitted in the through hole 51 and the male threaded portion 54 of the bolt 53 inserted through the through hole 57a of the cored bar arm portion 55a into the female threaded portion 47a of the sensor mounting nut 36a. It is fixed to 18c. In such a fixed state, the core metal arm portion 55a is sandwiched between the head of the bolt 53 (mounting flange portion 27a) and the sensor mounting nut 36a.

  Further, in the case of this example, the axially inner side extends over the entire circumference of the continuous portion between the axially inner end of the inner peripheral surface of the outer ring 4 and the radially inner end of the axially inner end surface of the outer ring 4. The chamfered portion 61 is formed so as to be inclined in the direction in which the inner diameter becomes larger as it goes to.

  The cap 18c as described above directly fits (metal fits) the outer peripheral surface of the outer half of the axial direction of the core metal cylindrical portion 39 to the inner peripheral surface of the inner end of the outer ring 4 in the axial direction. The flange portion 40b is assembled to the outer ring 4 by directly abutting the outer side surface of the flange portion 40b against the inner end surface of the outer ring 4 in the axial direction. In this assembled state, a portion of the outer surface in the axial direction of the core metal bottom portion 38 that is aligned with the sensor holding recess 60 has a predetermined axial gap (air gap) with respect to the detected surface of the encoder 21. ) Through close proximity.

  Further, in the state where the cap 18c is assembled to the outer ring 4 as described above, the chamfered portion 61, the inner end in the axial direction of the core metal cylindrical portion 39, and the inner end in the radial direction of the core metal flange portion 40b. A rubber O-ring 49 having a circular cross section corresponding to the annular sealing member recited in the claims is attached (externally fitted) between the outer peripheral surface of the continuous portion and the continuous portion.

  In the case of this example having the above-described configuration, the cap 18c is configured by only the fitting core metal 34b and the sensor mounting nut 36a without providing a synthetic resin portion. For this reason, compared with the case where insert molding of a synthetic resin is performed, the manufacturing cost can be reduced. About another structure and an effect, it is substantially the same as the case of the 1st example of embodiment mentioned above.

When practicing the present invention, the examples of the above-described embodiments can be implemented in appropriate combination.
Further, the structure of the sensor holding portion is not limited to the case of each example of the embodiment described above. For example, it may be configured by a circular bead (convex portion) formed on a portion of the inner side surface in the axial direction of the core metal bottom portion that is in an assembled state and opposed to the detected surface of the encoder (encoder main body) in the axial direction. it can.

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Rolling bearing unit with a rotational speed detection device 2 Rolling bearing unit 3 Rotational speed detection device 4 Outer ring 5 Hub 6 Rolling element 7a, 7b Outer ring raceway 8 Static side flange 9 Knuckle 10 Hub body 11 Inner ring 12 Caulking part 13a, 13b Inner ring raceway 14 Rotating flange 15 Cage 16 Inner space 17 Seal ring 18, 18a, 18b, 18c Cap 19 Bottom plate part 20 Cylindrical part 21 Encoder 22, 22a Sensor unit 23 Support ring 24 Encoder body 25, 25a Sensor holder 26, 26a Holder body 27, 27a Mounting flange part 28 Sensor insertion hole 29 Bolt 30 Screw hole 31 Fitting cylinder part 32 Outward flange part 33 Annular part 34, 34a, 34b Fitting core 35 Cover part 36, 36a Sensor attachment Nut 37, 37a Sensor holding part 38, 38a Core metal bottom part 39 Core metal cylindrical part 40, 40a, 40b Core metal flange part 41 Non-rotating notch 42, 42a First holding part 43 Thick part 44, 44a Nut holding part 45 Annular cover part 46 Concave groove 47, 47a Female thread part 48a, 48b Concave groove 49 O-ring 50 Sensor 51 Through-hole 52 Sleeve 53 Bolt 54 Male thread part 55, 55a Mandrel arm part 56 Axial extension part 57, 57a Through hole 58 Second holding Part 59 Mounting part 60 Sensor holding concave part 61 Chamfered part

Claims (5)

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 an output signal in response to a change in the characteristics of the detected surface of the encoder in a state of being opposed to the detected surface of the encoder, and holding the sensor, A sensor unit comprising a sensor holder supported on the opposing part;
A rolling bearing unit with a rotational speed detection device comprising:
The cap has a fitting core, a sensor mounting nut, and a sensor holding portion,
Of these, the fitting core is entirely made of a non-magnetic material, and the bottom of the core, the cylindrical core of the core that is bent at a right angle inward in the axial direction from the radially outer end of the core, It is a bottomed cylindrical shape with a cored bar flange part that is bent radially outward from an axially inner end of the cored bar cylindrical part,
The sensor mounting nut is supported by the fitting core, and is screwed with a bolt for fixing the sensor unit to the cap,
The sensor holding portion is provided in a portion of the cap that is opposed to the encoder in the axial direction, and the sensor and the encoder are at least engaged with an axially outer end portion of a holder main body constituting the sensor holder. For positioning with
The cap is assembled to the axially inner end of the outer ring in a state where the cored bar cylindrical portion is opened inward in the axial direction by being fitted and fixed to the axially inner end of the outer ring. And
In this state, the axial positioning of the cap with respect to the outer ring can be performed by directly or indirectly abutting the axially outer surface of the cored bar flange portion and the axially inner end surface of the outer ring in the axial direction. A rolling bearing unit with a rotational speed detection device, characterized in that the detection portion of the sensor faces the detection surface of the encoder through the core metal bottom.   The rolling bearing unit with a rotational speed detection device according to claim 1, wherein the sensor holding part is made of a synthetic resin and provided on a first holding part fixed to an inner side surface in the axial direction of the bottom part of the metal core.   The rolling bearing unit with a rotational speed detection device according to claim 1, wherein the sensor holding portion is directly formed on an inner surface in the axial direction of the bottom portion of the cored bar.   The sensor mounting nut is made of a synthetic resin, and is molded in a state in which the first holding portion is opened on the axial inner surface of the first holding portion, and is fixed to the axial inner surface of the core metal bottom. The rolling bearing unit with a rotational speed detection device according to any one of claims 1 to 3. The fitting cored bar has a radially inner end continuous to the cored bar cylindrical part, and a radially outer end positioned radially outward from a radially outer end of the axially inner end surface of the outer ring. It has a cored arm that has
The rolling bearing unit with a rotational speed detection device according to any one of claims 1 to 3, wherein the sensor mounting nut is supported by the core metal arm portion.

Images