JP2016142348A - Bearing cap and rolling bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure of a bearing cap which can effectively discharge foreign matters intruding into a holder insertion hole or a holder support part.SOLUTION: A bottomed holder insertion part 46 for inserting a tip of a rod-shaped holder main body part constituting a sensor holder therein is formed at a bottom plate part 39 which constitutes a bearing cap 33, and a holder support part 47 which protrudes from an axial inside face of the bottom plate part 39 toward the inside in an axial direction, and supports an intermediate part of the holder main body part without causing wobbling is formed at a periphery of an opening part of the holder insertion part 46. Then, an axial inside end face of the holder support part 47 is made to serve as a seat face part 55 which abuts on a side face of an attachment flange part which is arranged at a base end of the holder main body part. In addition to this, at a lower part of the seat face part 55, an upstream side end of the seat face part is opened at an internal peripheral face of the holder support part 47, and a drainage groove 56 is formed in which a downstream side end of the seat face part is opened at a lower face out of an external peripheral face of the holder support part 47.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bearing cap used for supporting an sensor while closing an axial end opening of an outer ring constituting a rolling bearing unit, and an improvement of a rolling bearing unit provided with the bearing cap.

  Combining a rolling bearing unit for supporting a wheel for supporting a wheel of an automobile rotatably with respect to a suspension device and a rotational speed detecting device for detecting the rotational speed of a wheel necessary for control of an ABS or the like. Conventionally, a rolling bearing unit with a rotational speed detecting device has been widely used.

  FIG. 10 shows one described in Patent Document 1 as an example of a conventional structure of such a rolling bearing unit with a rotational speed detection device. This rolling bearing unit 1 with a rotational speed detection device has a hub 3 that rotates together with a wheel (not shown) when used on an inner diameter side of an outer ring 2 that does not rotate while being supported and fixed to a suspension device when used. Is rotatably supported via a plurality of rolling elements 4 and 4. A fixed-side flange 5 is provided on the outer peripheral surface of the outer ring 2 to be coupled and fixed to a knuckle (not shown) constituting the suspension device. Further, the outer peripheral surface of the hub 3 is close to the outer end in the axial direction (“outer” with respect to the axial direction means the outer side in the width direction of the vehicle body when assembled to the vehicle, and is the left side of FIGS. On the other hand, the right side of FIGS. 1, 2, 5, 7, and 10, which is the center side in the width direction of the vehicle body, is referred to as “inside” with respect to the axial direction, and is the same throughout the present specification and claims. The part is provided with a rotation side flange 6 for supporting and fixing the wheel.

  Further, the axially outer end opening of the space where the rolling elements 4, 4 are installed between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 is closed by a seal ring 7. On the other hand, a bottomed cylindrical bearing cap 8 is attached to the inner end of the outer ring 2 in the axial direction so as to close the inner end opening of the outer ring 2 in the axial direction. The bearing cap 8 is made of a synthetic resin, and is composed of a cap main body 9 that is formed in a bottomed cylindrical shape and a metal ring 10 made of a metal plate molded on the cap main body 9. A fitting cylinder part 11 and a bottom plate part 12 extending radially inward from the axial inner end of the fitting cylinder part 11 are provided. Then, by fitting the metal ring 10 constituting the front half (axially outer half) of the fitting cylindrical part 11 to the outer peripheral surface of the axially inner end of the outer ring 2 with an interference fit, The outer ring 2 is attached to the inner end portion in the axial direction of the outer ring 2 in a state of closing the inner end opening in the axial direction of the outer ring 2.

  An annular encoder 13 constituting a rotational speed detecting device is supported and fixed concentrically with the hub 3 at the inner end in the axial direction of the hub 3. On the surface to be detected (the inner side surface in the axial direction) of the encoder 13, S poles and N poles are alternately arranged at equal pitches in the circumferential direction. Further, a synthetic resin sensor holder 14 constituting a rotational speed detecting device is supported and fixed to the bottom plate portion 12 constituting the bearing cap 8. For this purpose, a holder insertion hole 15 penetrating in the axial direction is formed in a portion of the bottom plate portion 12 that faces a part of the detected surface of the encoder 13 in the axial direction. A bolt insertion hole 16 is formed in a portion adjacent to the. Further, a nut 17 is heat caulked and fixed to the opening peripheral edge of the bolt insertion hole 16 in the axially outer side surface of the bottom plate portion 12. Then, a rod-shaped (cylindrical or quadrangular columnar) holder main body portion that embeds a sensor comprising an IC incorporating a magnetic detection element such as a Hall element and a waveform shaping circuit at the tip of the sensor holder 14. 18 is inserted into the holder insertion hole 15. Further, a mounting flange 19 provided at the base end of the holder main body 18 and a bolt 20 inserted through the bolt insertion hole 16 are screwed into the nut 17. Thereby, the sensor holder 14 is supported and fixed to the bearing cap 8.

  When the rolling bearing unit 1 with the rotational speed detecting device as described above is used, the fixed-side flange 5 fixed to the outer peripheral surface of the outer ring 2 is coupled and fixed to a suspension device with a bolt (not shown), and the hub By fixing the wheel to the rotation-side flange 6 fixed to the outer peripheral surface of the wheel 3 with stud bolts provided on the rotation-side flange 6, the wheel is supported rotatably with respect to the suspension device. When the wheel rotates in this state, the S pole and the N pole arranged on the detected surface of the encoder 13 alternately pass through the vicinity of the sensor held at the tip of the holder body 18. As a result, the density of the magnetic flux flowing in the detection part of this sensor changes, and its output signal changes. The frequency at which the sensor output signal changes in this way is proportional to the rotational speed of the wheel. Therefore, if this output signal is sent to a controller (not shown), ABS and TCS can be appropriately controlled.

  However, in the case of the first example of the conventional structure as described above, the following problem may occur. That is, since the holder main body portion 18 is inserted into the holder insertion hole 15 that passes through the bottom plate portion 12 constituting the bearing cap 8 in the axial direction, the bearing cap is inserted through the sensor insertion hole 15. There is a possibility that foreign matter such as muddy water may enter the space inside 8 (the axially outer side of the bottom plate portion 12). Further, not only the holder insertion hole 15 but also the bolt insertion hole 16 penetrates the bottom plate portion 12 in the axial direction, so that the sensor holder 14 is not yet supported and fixed to the bearing cap 8. In this state, foreign matter may enter the space inside the bearing cap 8 through the holes 15 and 16.

  In view of the circumstances as described above, for example, Patent Document 2 discloses a structure of a bearing cap 8a as shown in FIGS. A bearing cap 8a of the second example of this conventional structure is made of a synthetic resin, and is composed of a cap body 9a that is configured as a bottomed cylinder as a whole, and a metal ring 10a and a nut made of a metal plate molded on the cap body 9a. 17a, and includes a cylindrical fitting cylinder part 11a and a bottom plate part 12a extending radially inward from the axially inner end of the fitting cylinder part 11a. The bottom plate 12a is provided with a bottomed holder insertion hole 15a that is open only on the inner side in the axial direction for inserting the tip of the holder main body 18a constituting the sensor holder 14a. In addition, the outer peripheral surface of the intermediate portion of the holder main body portion 18a is supported without rattling around the holder insertion hole 15a in a state of projecting inward in the axial direction from the inner surface in the axial direction of the bottom plate portion 12a. For this purpose, a cylindrical holder support portion 21 is provided. The holder support 21 and the holder insertion hole 15a are used to position the sensor (embedded in the tip of the holder body 18a) via the holder body 18a. Further, the nut 17a is held by insert molding in a portion of the bottom plate portion 12a adjacent to the holder insertion hole 15a.

  In the case of the second example of the conventional structure having the above-described configuration, the holder insertion hole 15a is a bottomed hole that does not penetrate the bottom plate portion 12a in the axial direction. It is possible to prevent foreign matters such as the like from entering the inside of the bearing cap 8a. Further, the portion provided with the nut 17a also has a structure that does not penetrate the bottom plate portion 12a in the axial direction, so that foreign matter can be prevented from entering.

However, in the case of the second example of the conventional structure described above, it is difficult to efficiently discharge the foreign matter that has entered the holder insertion hole 15a or the holder support portion 21.
That is, in the case of the second example of the conventional structure, the cross-sectional shape (contour shape) of the inner peripheral surface of the holder support portion 21 is not a circular shape that matches the outer peripheral surface shape of the holder main body portion 18a. When the holder main body 18a is inserted inside the support portion 21, a shape (petal shape) in which gaps 22 and 22 having a substantially semicircular cross section are formed at four locations in the circumferential direction around the holder main body 18a. It is said. Accordingly, the foreign matter that has entered the holder insertion hole 15a or the holder support portion 21 is discharged to the outside using the gaps 22 and 22. However, since each of the gaps 22 and 22 has a long shape in the axial direction in which only the inner side in the axial direction is opened, it is difficult to completely discharge foreign matter through the gaps 22 and 22. There is a possibility that only moisture is discharged and mud accumulates inside. Further, the tip of the holder main body 18a may be damaged or the bottom of the holder insertion hole 15a may be damaged by mud accumulated inside or by freezing of water remaining inside.

JP-A-11-142424 International Publication No. 2014/044261

  In view of the above-described circumstances, the present invention has been invented to realize a structure of a bearing cap capable of effectively discharging foreign matter that has entered a holder insertion hole or a holder support portion.

Of the bearing cap and rolling bearing unit of the present invention, the invention relating to the bearing cap includes an outer ring in which a hub that supports an encoder at an inner end in the axial direction is rotatably supported on its inner diameter side via a plurality of rolling elements. The axial inner end opening of the outer ring is attached to the axial inner end of the outer ring, and the sensor holder is supported and fixed to a part thereof.
Further, the bearing cap according to the present invention has a bottomed cylindrical shape as a whole, a fitting cylinder portion fitted and fixed to the inner end portion in the axial direction of the outer ring, and an axial direction of the fitting cylinder portion And a bottom plate portion provided in a state of extending radially inward from a part (for example, an inner end portion in the axial direction), and at least the bottom plate portion is made by injection molding a synthetic resin.
Further, in the bottom plate portion, a portion facing the part of the encoder with respect to the axial direction is provided with a sensor inside the rod main body (columnar shape, quadrangular prism shape, etc.) of the rod holder constituting the sensor holder. A bottomed holder insertion hole that is open only on the inner side in the axial direction is provided for inserting the held tip. Further, a portion of the holder main body protruding from the holder insertion hole in a state of protruding from the axial inner side surface of the bottom plate portion toward the axial inner side around the opening of the holder insertion hole ( A holder support portion is provided for supporting the intermediate portion of the holder main body portion without rattling. Also, a seating surface portion is provided on the inner end surface in the axial direction of the holder support portion so that the side surface of the mounting flange portion provided on the portion of the holder main body portion exposed from the holder support portion abuts.
In particular, in the case of the bearing cap of the present invention, a drainage groove is formed in the seat surface portion, and the upstream end portion of the drainage groove is below the inner peripheral surface of the holder support portion in use. The downstream end is open in the portion of the outer peripheral surface of the holder support portion that is positioned below the upstream end in the use state. When carrying out the present invention, various shapes such as an oval shape, a rectangular shape, and a bowl shape can be adopted as the contour shape viewed from the axial direction of the outer peripheral surface of the holder support portion.

Further, when the bearing cap of the present invention is implemented, for example, as in the invention according to claim 2, the outer peripheral surface of the holder support portion is in a direction orthogonal to the axial direction and the vertical direction in use. A downstream end of the drainage groove can be opened on a side surface in a certain width direction.
In this case, for example, a portion of the side surface in the width direction of the holder support portion that opens the downstream end of the drainage groove can be a recessed portion that is recessed in the width direction.
Also, in this case, for example, two drainage grooves are formed in a state where they are inclined away from each other as they go downward in the usage state {when viewed from the axial direction in the usage state Can be formed in an inverted V shape (inverted V shape).

When the bearing cap of the present invention as described above is implemented, for example, the bottom plate portion formed by holding a nut by insert molding in a portion of the bottom plate portion adjacent to the holder insertion hole. It is possible to provide a nut holding portion that does not penetrate the shaft in the axial direction.
When such a nut holding portion is provided, the nut holding portion and the holder support portion may be provided integrally (for example, the nut holding portion is provided as a part of the holder support portion). it can.
Furthermore, when providing the said nut holding part, the axial direction inner end surface of this nut holding part and the axial direction inner end surface of the said holder support part can be located on the same virtual plane.

On the other hand, the rolling bearing unit of the present invention is, for example, for rotatably supporting a wheel (driven wheel) of an automobile, and includes an outer ring, a hub, a plurality of rolling elements, an encoder, and a bearing cap. .
Of these, the outer ring has a single-row or double-row outer ring raceway on the inner peripheral surface.
The hub has a single-row or double-row inner ring raceway on the outer peripheral surface, and rotates during use.
Each rolling element is provided between the outer ring raceway and the inner ring raceway so as to be freely rollable. As each of these rolling elements, a ball, a tapered roller, a cylindrical roller, a spherical roller, a needle or the like can be used.
The encoder is supported and fixed concentrically with the hub at the inner end of the hub in the axial direction, and its characteristics are changed alternately and at equal pitches in the circumferential direction.
Further, the bearing cap is attached to the inner end of the outer ring in the axial direction while closing the axial inner end opening of the outer ring, and a sensor holder is supported and fixed to a part of the bearing cap.
In particular, in the case of the rolling bearing unit of the present invention, any one of the bearing caps described in claims 1 and 2 is used as the bearing cap.

According to the bearing cap and the rolling bearing unit of the present invention configured as described above, foreign matter that has entered the holder insertion hole or the holder support provided in the bottom plate portion constituting the bearing cap can be effectively discharged. it can.
That is, in the case of the present invention, a drainage groove is formed in the seat surface portion provided on the inner end surface in the axial direction of the holder support portion for contacting the side surface of the mounting flange portion constituting the sensor holder. . The drainage groove has an upstream end that opens to a portion of the inner peripheral surface of the holder support portion that is positioned below in use, and a downstream end that is the outer peripheral surface of the holder support portion. Among these, it opens in the part located below the said upstream end part in use condition. In use, the opening of the drainage groove with respect to the seat surface is closed by the mounting flange, but the upstream and downstream ends of the drainage groove are closed by the mounting flange. There is nothing. For this reason, in the case of this invention, the foreign material which penetrate | invaded into the said holder insertion hole or the said holder support part can be effectively discharged | emitted outside through the said drain groove using the effect | action of gravity.

Sectional drawing of the rolling bearing unit with a rotational speed detection apparatus which shows the 1st example of embodiment of this invention. Sectional drawing which similarly takes out and shows a bearing cap. The end view which takes out and shows a bearing cap similarly. Similarly AA sectional drawing of FIG. The figure equivalent to FIG. 2 which shows the 2nd example of embodiment of this invention. The figure which corresponds to FIG. 3 similarly. The figure equivalent to FIG. 2 which shows the 3rd example of embodiment of this invention. The figure which corresponds to FIG. 3 similarly. The figure equivalent to FIG. 3 which shows the 4th example of embodiment of this invention. Sectional drawing which shows the rolling bearing unit with a rotational speed detection apparatus of the 1st example of the conventional structure. The end view which takes out and shows the bearing cap regarding the 2nd example of conventional structure. Similarly BB sectional drawing of FIG.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS. The feature of this example is that the structure of the bearing cap 33 for closing the axially inner end opening of the outer ring 2 is devised. Since the configuration and operational effects of the other parts are basically the same as those of the above-described conventional structure, the following description will focus on the characteristic parts of this example and the parts not previously described.

  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 and detects the rotational speed of this wheel. A hub 3, which is a rotating wheel, is rotatably supported on a radially inner side of a certain outer ring 2 via a plurality of rolling elements 4, 4.

  The outer ring 2 has a fixed-side flange 5 for coupling and fixing to a knuckle (not shown) constituting a suspension device on the outer peripheral surface, and double-row outer ring raceways 23a and 23b on the inner peripheral surface. The hub 3 is formed by connecting and fixing a hub body 24 and an inner ring 25 by a caulking portion 26. The hub 3 has double-row inner ring raceways 27a and 27b on the outer peripheral surface, and is arranged on the inner diameter side of the outer ring 2. The outer ring 2 is supported concentrically. A rotation-side flange 6 for supporting the wheel is provided at a portion of the hub main body 24 that protrudes outward in the axial direction from the axial outer end opening of the outer ring 2. . A plurality of rolling elements 4, 4 are provided between the outer ring raceways 23a, 23b and the inner ring raceways 27a, 27b. In the example shown in the figure, balls are used as the rolling elements 4 and 4, but in the case of a rolling bearing unit for automobiles that is heavy in weight, tapered rollers may be used.

  The hub body 24 constituting the outer ring 2 and the hub 3 is made of medium carbon steel such as S53C, and at least the surfaces of the raceways 23a, 23b, 27a are subjected to a hardening process such as induction hardening. . On the other hand, the inner ring 25 and the rolling elements 4 and 4 constituting the hub 3 are made of high carbon chrome bearing steel such as SUJ2, and are subjected to a hardening process by, for example, full quenching.

  An annular encoder 13 constituting a rotational speed detecting device is supported and fixed concentrically with the hub 3 at an inner end in the axial direction of the inner ring 25 constituting the hub 3. The encoder 13 includes a support ring 28 and an encoder main body 29. Of these, the support ring 28 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 rolled steel plate such as SPCC. The support ring 28 is provided with a cylindrical fitting portion 30 and an outward direction bent in a radially outward direction from an axially outer end portion (left end portion in FIGS. 1 and 2) of the fitting portion 30. It is comprised from the collar part 31 and the annular ring part 32 provided in the state bent from the axial direction inner end part of the said fitting part 30 to radial inside. The fitting portion 30 is provided in the outer half portion in the axial direction and is provided in the inner half portion in the axial direction and a small-diameter portion that is directly fitted on the inner end portion in the axial direction of the inner ring 25. And a taper portion that is inclined in a direction in which the outer diameter increases as it goes. The encoder main body 29 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. In the circumferential direction, they are changed alternately and at equal pitches. Thereby, the south pole and the north pole are alternately arranged at equal pitches in the circumferential direction on the inner side surface (detected surface) of the encoder body 29 in the axial direction. In such a state that such an encoder body 29 is attached and fixed to the inner side surface in the axial direction of the annular portion 32, the inner side surface (detected surface) of the encoder body 29 is set in the axial direction of the hub body 24. The caulking portion 26 formed at the inner end portion is positioned inward in the axial direction from the inner end surface in the axial direction.

  Further, the axially outer end opening of the space where the rolling elements 4, 4 are installed between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 is closed by a seal ring 7. On the other hand, a bottomed cylindrical bearing cap 33 is attached to the inner end of the outer ring 2 in the axial direction so as to close the inner end opening of the outer ring 2 in the axial direction. The bearing cap 33 is supported and fixed with a sensor holder 14b made of synthetic resin, which constitutes the rotational speed detection device in use. The sensor holder 14b includes a cylindrical (rod-shaped) holder main body portion 18b and a mounting flange portion 19b provided at the base end portion of the holder main body portion 18b. Further, a sensor (not shown) composed of an IC incorporating a magnetic sensing element such as a Hall IC, Hall element, MR element, GMR element and a waveform shaping circuit is embedded in the tip of the holder main body 18b.

  The bearing cap 33 is composed of a cap body 34 made of a synthetic resin and having a bottomed cylindrical shape, a metal ring 35 and a nut 37 and an O-ring 36 fixed to the cap body 34 by molding. And a substantially cylindrical fitting tube portion 38 and a substantially disc-shaped bottom plate portion 39 extending radially inward from the axially inner end portion of the fitting tube portion 38.

  The cap body 34 is made, for example, by injection molding a fiber reinforced polyamide resin material in which glass fiber is appropriately added to polyamide 66 resin. In addition, if necessary, 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 added to the polyamide resin. Water resistance may be further improved by adding appropriately. In the case of this example, the metal ring 35 and the nut 37 are fixed to the cap main body 34 by mold fixing at the time of injection molding of the cap main body 34.

  The fitting cylinder portion 38 constituting the bearing cap 33 includes a small-diameter cylinder portion 40 provided in a front half portion (an outer half portion in the axial direction, a left half portion in FIGS. 1 and 2, a lower half portion in FIG. 4), A stepped cylindrical shape in which a large-diameter cylindrical portion 41 provided in a base half portion (an inner half portion in the axial direction, a right half portion in FIGS. It is configured. In the case of this example, the outer diameter side portion of the small diameter cylindrical portion 40 is constituted by the metal ring 35. The metal ring 35 is made of a stainless steel plate, a cold-rolled steel plate, or the like, has an L-shaped cross section, a cylindrical portion 43, and an outward flange that is bent radially outward from an axial inner end of the cylindrical portion 43. Part 44. Among these, the cylindrical portion 43 is exposed on the outer peripheral surface of the small-diameter cylindrical portion 40, whereas the outward flange portion 44 is embedded in the large-diameter cylindrical portion 41. Further, the inner diameter side portion of the stepped surface 42 is used as a locking groove for the O-ring 36 disposed adjacent to the outer side surface of the outward flange portion 44 in the axial direction. 36 is locked.

  The bottom plate portion 39 has a substantially disk shape as a whole, and a part of the bottom plate portion 39 has an axial thickness dimension larger than that of other portions (bulged outward in the axial direction). A thick part 45 is provided. Further, in the thick portion 45, a portion facing a part of the detection surface of the encoder 13 (encoder main body 29) in the axial direction in a use state (a state in which the bearing cap 33 is attached to the outer ring 2). In addition, a bottomed holder insertion hole 46 that is open only on the inner side in the axial direction is provided in a portion located at the upper end in the vertical direction. The holder insertion hole 46 is for inserting the tip of the holder body 18b constituting the sensor holder 14b without rattling, and is slightly larger than the outer diameter of the tip of the holder body 18b. Has an inner diameter dimension.

  Further, the outer peripheral surface of the intermediate portion of the holder main body portion 18b is rattled around the opening portion of the holder insertion hole 46 in a state of protruding from the inner surface in the axial direction of the bottom plate portion 39 toward the inner side in the axial direction. A holder support portion 47 is provided to support without any problem. The contour shape seen from the axial direction of the outer peripheral surface of the holder support portion 47 is a substantially oval shape extending in a substantially horizontal direction (left-right direction in FIGS. 3 to 4), as shown in FIG. In the case of this example, in order to support the outer peripheral surface of the intermediate portion of the holder main body portion 18b on the horizontal half portion (the left half portion in FIGS. 3 to 4) of the holder support portion 47 without rattling. The holder support hole 48 is provided concentrically with the holder insertion hole 46. The holder support hole 48 has an inner diameter that is slightly larger than the outer diameter of the outer peripheral surface of the intermediate portion of the holder body 18b. In the case of this example, a nut holding portion 49 is configured by the other half portion in the horizontal direction of the holder support portion 47 (the right half portion in FIGS. The nut holding portion 49 has the nut 37 inserted (embedded) therein. The nut holding portion 49 opens only on the inner side surface in the axial direction of the thick portion 45, and has a bottomed holding concave portion 50 in which the axial outer end portion (base end portion) of the nut 37 is fixed inside. And a holding cylinder 51 formed around the opening of the holding recess 50 so as to protrude inward in the axial direction from the inner side in the axial direction of the thick portion 45, and covering the periphery of the nut 37. It is composed of The holding recess 50 and the holding cylinder portion 51 are integrally formed, and engaging protrusions 52 and 52 are formed on the inner peripheral surfaces of the holding recess 50 and the holding cylinder portion 51, respectively. Yes. On the other hand, the nut 37 is a bottomed cylindrical cap nut, and an internal thread portion 53 is formed on the inner peripheral surface, and engagement grooves 54 and 54 are formed on the outer peripheral surface. Then, engaging ridges 52, 52 formed on the inner peripheral surface of the nut holding portion 49 are engaged with the engaging grooves 54, 54, respectively. The axial inner end surface of the nut 37 and the axial inner end surface of the holder support portion 47 including the nut holding portion 49 (holding cylinder portion 51) are located on the same virtual plane, and the sensor A seating surface portion 55 is provided for contacting the outer surface in the axial direction of the mounting flange portion 19b constituting the holder 14b.

  In this example, since the nut 37 has a structure that does not penetrate in the axial direction (cap nut), it is not necessary to screw the nut 37 into the male thread portion during insert molding, and the workability of insert molding. Can be improved. On the other hand, when the nut has a structure penetrating in the axial direction, insert molding is performed in a state where the nut is screwed with the male screw portion so that the resin does not enter the inside of the nut. The method for fixing the nut 37 is not limited to insert molding, and various conventionally known methods such as press fitting can be employed.

  In the case of this example, a drainage groove 56 is formed in a portion of the seat surface portion 55 located below the holder support hole 48 so as to extend in the vertical direction. In addition to being open to the seat surface portion 55, the drain groove 56 has an upper end that is an upstream side end portion of the inner peripheral surface of the holder support hole 48 (the holder support portion 47). The lower end of the axially inner end of the portion located at the lower end and the lower end, which is the downstream end thereof, of the lower side that is part of the outer peripheral surface of the holder support 47 is the holder support The hole 48 opens at the inner end in the axial direction of the portion located below the lower end of the inner peripheral surface of the hole 48.

  The bearing cap 33 of the present example having the above-described configuration is internally fitted and fixed by tightly fitting the small-diameter cylindrical portion 40 (cylindrical portion 43) of the fitting cylindrical portion 38 to the axially inner end portion of the outer ring 2. By doing so, the outer ring 2 is mounted on the inner end portion in the axial direction of the outer ring 2 in a state of closing the inner end opening in the axial direction. Further, in this state, the stepped surface 42 is abutted against the inner end surface of the outer ring 2 in the axial direction, thereby positioning the bearing cap 33 with respect to the outer ring 2 in the axial direction. At the same time, the O-ring 36 is elastically compressed between the inner end surface in the axial direction of the outer ring 2 and the outer surface in the axial direction of the outward flange portion 44, thereby sealing a portion between these both side surfaces. The And the axial direction outer side surface of the part which comprises the bottom part of the said holder insertion hole 46 among the said baseplate part 39 adjoins and opposes the to-be-detected surface of the said encoder 13 (encoder main body 29).

  In the case of this example, the sensor holder 14b is supported and fixed to the bearing cap 33 having the above-described configuration as follows. That is, of the rod-shaped holder main body 18b constituting the sensor holder 14b, the tip end portion in which the sensor is embedded is disposed (inserted) inside the holder insertion hole 46 without rattling, and the intermediate portion Is arranged inside the holder support hole 48 without rattling. And the axial direction outer side surface of the mounting flange part 19b provided in the base end part of the said holder main body 18b is made to contact | abut to the said seat surface part 55. FIG. In this state, the holder support hole 48 and the opening portion on the seat surface 55 side of the drainage groove 56 are covered with the mounting flange portion 19b. Further, in this state, a bolt (not shown) is inserted into the mounting flange portion 19b, and the male screw portion provided at the tip portion of the bolt is screwed into the female screw portion 53 of the nut 37 and further tightened. As a result, the sensor is brought close to and opposed to the encoder 13 (the surface to be detected of the encoder body 29) via the bottom of the holder insertion hole 46.

  In the case of the rolling bearing unit 1a with the rotational speed detection device of the present example having the above-described configuration, the driven wheel is supported rotatably with respect to the suspension device as in the case of the conventional structure described above. It is possible to detect the rotational speed of this wheel. For this reason, ABS and TCS can be controlled appropriately.

In particular, in the case of this example, the foreign matter that has entered the holder insertion hole 46 and the holder support hole 48 (the holder support portion 47) for positioning the sensor via the holder main body portion 18a, The drainage groove 56 can efficiently discharge the water.
That is, in the case of this example, the seat surface portion 55 provided on the inner end surface in the axial direction of the holder support portion 47 for contacting the outer surface in the axial direction of the mounting flange portion 19b constituting the sensor holder 14b. A drainage groove 56 is formed. The drainage groove 56 has an upstream end that is open to an axially inner end of a portion of the inner peripheral surface of the holder support hole 48 that is positioned at the lower end in use, and a downstream end that is Of the lower side surface, which is a part of the outer peripheral surface of the holder support portion 47, an opening is made at the axially inner end portion of the portion located below the lower end of the inner peripheral surface of the holder support hole 48. In use, the seat groove 55 side opening of the drainage groove 56 is covered by the mounting flange portion 19b. The upstream and downstream end openings of the drainage groove 56 are covered by the mounting flange portion 19b. It will not be blocked. For this reason, in the case of this example, it is assumed that the water from which mud has been filtered is inserted into the holder through a minute gap that exists in the contact portion between the seat surface portion 55 and the axially outer surface of the mounting flange portion 19b. Even if the muddy water penetrates into the holes 46 and the holder support holes 48 or the muddy water enters through the drainage grooves 56, foreign matter such as water or muddy water filtered through the mud is removed by the action of gravity. Can be effectively discharged to the outside through the drainage groove 56. As a result, it is possible to effectively prevent foreign matter from being discharged from the inside of the holder insertion hole 46 and the holder support hole 48 or only moisture from being discharged and accumulation of mud inside. In addition, it is possible to effectively prevent the tip of the holder body 18b from being damaged or the bottom of the holder insertion hole 46 from being damaged by mud accumulated inside or by freezing of water remaining inside.

  In the case of this example, the holder support hole 48 does not open directly to the outside in the state of use. Therefore, it is possible to prevent the muddy water splashed from the road surface from directly falling on the opening of the holder support hole 48 and entering the holder support hole 48 and the holder insertion hole 46. In the case of this example, the holder support hole 48 communicates with the outside through the drainage groove 56, but the downstream end (opening with respect to the outside) of the drainage groove 56 is formed on the drainage groove 56. It is located below the upstream end (opening with respect to the inside of the holder support hole 48). For this reason, it is possible to effectively prevent the muddy water splashed from the road surface from entering the inside of the holder support hole 48 and the holder insertion hole 46 through the drainage groove 56 by the action of gravity and the labyrinth effect. Even if it enters, it can be effectively discharged as described above).

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS. This example is a modification of the first example of the above-described embodiment, and the feature thereof is the structure of the holder support portion 47a (holder support hole 48a) constituting the bearing cap 33a. That is, in the case of this example, of the inner peripheral surface of the holder support hole 48a, the portion located at the lower end in use and adjacent to the drain groove 56 in the axial direction (left side in FIG. 5). An inclined surface portion 57 that is inclined in a downward direction as it goes inward in the axial direction (right side in FIG. 5) is provided in the portion.

In the case of this example having the above-described configuration, foreign matter that has entered the holder insertion hole 46 or the holder support hole 48a is guided toward the drainage groove 56 along the inclined surface portion 57 by the action of gravity. I can do it. For this reason, this foreign material can be discharged more effectively. When the present invention is implemented, the inclination angle and the axial length of the inclined surface portion 57 with respect to the axial direction can be changed as appropriate.
About another structure and an effect, it is the same as that of the case of the 1st example of the said embodiment.

[Third example of embodiment]
A third example of the embodiment of the present invention will be described with reference to FIGS. This example is a modification of the first example of the above-described embodiment, and the feature thereof is the structure of the holder support portion 47b constituting the bearing cap 33b. That is, in the case of this example, the contour shape of the holder support portion 47b viewed from the axial direction is a substantially oval shape extending in the vertical direction as shown in FIG. A holder support hole 48 is provided in the upper half portion of the holder support portion 47b, and a nut holding portion 49a is constituted by the lower half portion of the holder support portion 47b. In the case of this example, the axially inner end surface of the holder support portion 47b and the axially inner end surface of the nut 37 are the seating surface portion 55a for contacting the axially outer surface of the mounting flange portion constituting the sensor holder. A pair of drain grooves 56a, 56a is seen from the axial direction in a portion that is out of the inner end surface in the axial direction of the nut 37 and adjacent to the holder support hole 48 below. In this case, as shown in FIG. 8, it is formed in a state where it is arranged in an inverted V shape (inverted V shape). These drainage grooves 56a, 56a are open to the seat surface portion 55a, and the upper end portion, which is the upstream end portion, is formed on the inner peripheral surface of the holder support hole 48 (the holder support portion 47b). Of these holder support portions 47b, the lower end portion that is open at the axially inner end portion of the lower end portion and the lower end portion that is the downstream end portion is a part of the outer peripheral surface of the holder support portion 47b. Of the both sides of the width direction (the direction perpendicular to the axial direction and the up-down direction, and the left-right direction in FIG. 8), in the axial direction of the portion located obliquely downward from the lower end of the inner peripheral surface of the holder support hole 48 Opened at the end.
Furthermore, in the case of this example, the inner peripheral surface of the cylindrical portion 43 constituting the metal ring 35 is exposed, and the bottom plate portion 39 constituting the cap body 34 corresponds to the holder support portion 47b. This is different from the first example of the above embodiment in that the portion to be made is not a thick portion bulged outward in the axial direction.

In the case of this example having the above-described configuration, the number of drain grooves 56a formed in the seat surface portion 55a is two. For this reason, the discharge | emission performance of the foreign material which penetrate | invaded in the said holder support hole 48 and the holder insertion hole 46 can be improved. Further, the lower end portions of the drain grooves 56a and 56a are opened on both side surfaces of the holder support portion 47b in the width direction. For this reason, it is possible to make it difficult for the muddy water splashed from the road surface to enter the drain grooves 56a and 56a through these openings.
About another structure and an effect, it is the same as that of the case of the 1st example of the said embodiment.

[Fourth Example of Embodiment]
A fourth example of the embodiment of the present invention will be described with reference to FIG. This example is a modification of the third example of the embodiment described above, and the feature thereof is in the structure of the holder support portion 47c constituting the bearing cap 33c. That is, in the case of this example, the recessed portions 58 and 58 that are recessed in the width direction are provided in the center portion in the vertical direction of both side surfaces of the holder support portion 47c in the width direction (left and right direction in FIG. 9). The contour shape viewed from the axial direction of the outer peripheral surface of the holder support portion 47c is a bowl shape. And the lower end part which is a downstream edge part of a pair of drainage grooves 56b and 56b is opened to the axial direction inner end part of these two recessed parts 58 and 58 at the bottom part.

In the case of the present example having the above-described configuration, portions of the both sides of the holder support portion 47c in the width direction where the lower ends of the drainage grooves 56b, 56b are opened (the both recessed portions 58, 58). The bottom part of the drainage grooves 56b, 56b projects outward in the width direction (both sides). For this reason, the projecting portion can protect the lower end openings of the drain grooves 56b and 56b against muddy water splashed from the road surface. Therefore, the muddy water can be more difficult to enter the drainage grooves 56b and 56b through the lower end openings of the drainage grooves 56b and 56b.
About another structure and an effect, it is the same as that of the case of the 3rd example of the said embodiment.

  In each example of the embodiment described above, the bearing cap has been described by taking as an example a structure in which a synthetic resin cap body and a member made of a material other than synthetic resin, such as a metallic metal ring, are combined. However, the entire bearing cap of the present invention may be made of synthetic resin. In each example of the above embodiment, the rolling bearing unit of the present invention has been described as applied to a rolling bearing unit for supporting a wheel. However, the rolling bearing unit of the present invention is used for such applications. It is not limited, For example, it can apply to various uses, such as a machine tool. In addition, the structures of the examples of the above-described embodiments can be implemented in appropriate combination.

DESCRIPTION OF SYMBOLS 1, 1a Rolling bearing unit 2 Outer ring 3 Hub 4 Rolling body 5 Fixed side flange 6 Rotating side flange 7 Seal ring 8, 8a Bearing cap 9, 9a Cap body,
10, 10a Metal ring 11, 11a Fitting cylinder part 12, 12a Bottom plate part 13 Encoder 14, 14a, 14b Sensor holder 15, 15a Holder insertion hole 16 Bolt insertion hole 17, 17a Nut 18, 18a, 18b Holder main body part 19, 19a, 19b Mounting flange part 20 Bolt 21 Holder support part 22 Gap 23a, 23b Outer ring raceway 24 Hub body 25 Inner ring 26 Caulking part 27a, 27b Inner ring raceway 28 Support ring 29 Encoder body 30 Fitting part 31 Outward flange part 32 Circular ring part 33, 33a to 33c Bearing cap 34 Cap body 35 Metal ring 36 O-ring 37 Nut 38 Fitting cylinder part 39 Bottom plate part 40 Small diameter cylinder part 41 Large diameter cylinder part 42 Step surface 43 Cylindrical part 44 Outward flange part 45 Thick part 46 Holder insertion hole 47, 47a to 47c Holder support 48,48a holder support holes 49,49a nut holding portion 50 holding recess 51 holding tubular portion 52 Kakarigototsujo 53 internally threaded portion 54 engaging recessed groove 55,55a seat surface portion 56, 56a, 56b drainage groove 57 inclined surface 58 recess

Claims (3)

The axial inner end of the outer ring is closed with the axial inner end opening of the outer ring supporting the hub supporting the encoder at the inner end in the axial direction and rotatably supporting the inner diameter side via a plurality of rolling elements. A bearing cap on which a sensor holder is supported and fixed.
The bearing cap includes a fitting cylinder portion that is fitted and fixed to the inner end portion in the axial direction of the outer ring, and a bottom plate portion that is provided so as to extend radially inward from a part of the fitting cylinder portion in the axial direction. And at least the bottom plate is made by injection molding synthetic resin,
A shaft for inserting a tip portion holding a sensor inside of a rod-shaped holder main body portion constituting the sensor holder into a portion of the bottom plate portion facing a part of the encoder in the axial direction. A bottomed holder insertion hole that is open only on the inner side in the direction is provided, and protrudes inward in the axial direction from the inner side in the axial direction of the bottom plate portion around the opening of the holder insertion hole. In the state, a holder support portion is provided for supporting a portion of the holder main body portion protruding from the holder insertion hole, and the holder main body portion is provided on the inner end surface in the axial direction of the holder support portion. Among them, there is provided a seating surface part for contacting the side surface of the mounting flange part provided in the part exposed from the holder support part,
A drainage groove is formed in the seat surface portion, and an upstream end of the drainage groove is open to a portion located below in the use state on the inner peripheral surface of the holder support portion. The end portion is open in a portion of the outer peripheral surface of the holder support portion located below the upstream end portion in use.
Bearing cap characterized by things. Of the outer peripheral surface of the holder support portion, the downstream end of the drainage groove is open on the side surface in the width direction, which is the direction orthogonal to the axial direction and the up-down direction in use.
The bearing cap according to claim 1.   An outer ring that has an outer ring raceway on the inner peripheral surface, and an outer ring that does not rotate during use, a hub that has an inner ring raceway on the outer peripheral surface and that rotates during use, and is provided between the outer ring raceway and the inner ring raceway so as to be able to roll. A plurality of rolling elements, an encoder which is supported and fixed concentrically with the hub at the inner end of the hub in the axial direction, and whose characteristics are changed alternately and at equal pitches in the circumferential direction, and the axial direction of the outer ring A rolling bearing unit including a bearing cap that is attached to an axially inner end portion of the outer ring in a state in which the inner end opening is closed, and in which a sensor holder is supported and fixed. A rolling bearing unit characterized by being the bearing cap according to any one of claims 1 and 2.

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