JP2006144992A - Rolling bearing unit with rotating speed detecting device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it difficult to deposit electrodeposition coating paint on a female screw portion 25 of a nut 20 even when applying an electrodeposition coating to the nut 20 after fixed to a cover 13 without applying masking to the female screw portion 25 of the nut 20. <P>SOLUTION: Before the nut 20 is fixed to a through-hole 17 of the cover 13, zinc plating treatment is given to the nut 20. After the nut 20 to which the zinc plating treatment is given is fixed to the cover 13, the electrodeposition coating is applied thereto. On the nut 20 whose surface is coated with a zinc plating layer, the electrodeposition coating paint is hardly deposited. Thus, no need exists for applying masking to the female screw portion 25, solving the above issue. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The rolling bearing unit with a rotational speed detecting device and the manufacturing method thereof according to the present invention are used for rotatably supporting a vehicle wheel with respect to a suspension device and detecting the rotational speed of the wheel.

  A rolling bearing unit is used to rotatably support the wheels of the automobile with respect to the suspension system. Further, in order to control the anti-lock brake system (ABS) and the traction control system (TCS), it is necessary to detect the rotational speed of the wheel. As a rolling bearing unit with a rotational speed detection device used for this purpose, for example, those described in Patent Documents 1 and 2 have been known. Of these, in the case of the conventional structure described in Patent Document 1, the inner end of the outer ring which is a stationary wheel (inner with respect to the axial direction refers to the center in the width direction in the assembled state to the vehicle. The outside in the width direction in the assembled state is referred to as the outside in the axial direction. The same applies throughout this specification.) The sensor is supported and fixed to the cover fitted and fixed to the part using bolts fixed to the cover by welding. ing. In addition, in the case of the conventional structure described in Patent Document 2, a sensor is supported on this cover using a nut or bolt that is fitted and fixed in a bottomed recess provided in a part of a metal cover. It is fixed.

  Among the conventional structures as described above, in the case of the structure described in Patent Document 1, there is a possibility that the cover is deformed as the bolt is welded to the cover. In the case of deformation, it is difficult to accurately regulate the positional relationship between the sensor and encoder, which is disadvantageous in terms of accurately detecting the rotational speed. In addition, in the case of the structure described in Patent Document 2, it is troublesome to form a bottomed recess in a part of a metal cover, and to fit and fix a nut or bolt in the recess, which is costly. Causes it to become bulky.

  In view of the circumstances as described above, Japanese Patent Application No. 2004-151522 discloses an invention relating to a rolling bearing unit with a rotational speed detection device that can prevent harmful deformation of the cover and accurately detect rotational speed ( (Prior invention) is disclosed. In the case of this prior invention, the sensor is fixed to the cover by screwing and tightening a nut that is plastically deformed on a part of the cover and fixed to the cover and a bolt inserted through a holder holding the sensor. ing. For this reason, it is not necessary to weld a nut or a bolt to the cover. In the case of the above-mentioned prior invention, the work for fixing the nut to the cover is performed by pressing the nut while the cover is placed on a flat surface such as a receiving plate, which may cause harmful distortion to the cover. Absent. Therefore, the position relationship between the detection surface of the permanent magnets and the detection part of the sensor and the detection part of the sensor can be accurately regulated as designed without any troublesome adjustment work. The rotation speed can be accurately detected without increasing the volume. Furthermore, a troublesome operation of forming a bottomed recess in a part of the cover and fitting and fixing a nut or a bolt in the recess becomes unnecessary, and from this aspect, it can be configured at low cost.

  However, in the case of the above-described invention, rain water or the like may enter the cover from rain or the like between the cover and the holder during rainy weather driving or car washing. Rainwater, etc. that has entered the cover can be discharged to the outside through a drain hole provided in the cover, but the cover made of steel (for example, SPCC material) is made of steel, and the nut fixed to the cover is made of steel May be rusted when exposed to rainwater or the like. In order to prevent the occurrence of such rust, it is conceivable to subject the cover and the nut fixed to the cover to rust prevention treatment by cationic electrodeposition over the entire surface (both front and back surfaces). However, when the cationic electrodeposition coating is applied in this way, the paint by the cationic electrodeposition coating may adhere to the female thread portion of the nut. The paint adhering to the internal thread portion is not preferable because the internal diameter (pitch circle diameter) of the internal thread is made smaller than a specified value and it is difficult to tighten the nut and the bolt for fixing the holder. . In order to prevent the paint from adhering to the female screw portion, it is conceivable to mask the female screw portion. However, the masking operation is troublesome and causes an increase in cost.

Japanese Utility Model Publication No. 7-31539 Japanese Patent No. 3440800

  In view of the circumstances as described above, the present invention provides an electrodeposition method on the female threaded portion of the nut without masking the female threaded portion of the nut, even if the electrodeposition coating is applied after the nut is fixed to the cover. This invention was invented to realize a structure in which paint by paint hardly adheres at low cost.

Of the rolling bearing unit with a rotational speed detection device and the manufacturing method thereof according to the present invention, the rolling bearing unit with a rotational speed detection device according to claim 1 is the same as the rolling bearing unit with a rotational speed detection device described above. A stationary wheel, a rotating wheel, a plurality of rolling elements, an encoder, a metal cover, an insertion hole, a sensor, and a holder.
Among these, the stationary wheel has a stationary side track on the stationary side peripheral surface, and does not rotate during use.
The rotating wheel has a rotation-side track on the rotation-side peripheral surface facing the stationary-side peripheral surface, and rotates during use.
Each of the rolling elements is provided between the stationary side track and the rotation side track so as to freely roll.
The encoder is fixed to a part of the rotating wheel concentrically with the rotating wheel, and the characteristics of the detected surface provided on one side surface in the axial direction, the inner peripheral surface or the outer peripheral surface, etc. The direction is changed alternately (generally at regular intervals).
The metal cover (made of an iron alloy plate such as a mild steel plate) is fixed to a part of the stationary ring.
The insertion hole is provided in a part of the cover.
The sensor is supported by a part of the cover in a state of being inserted through the insertion hole, and changes the output as the encoder rotates.
The holder includes an insertion portion and a mounting flange portion that are inserted into the insertion hole while holding the sensor.
In addition, a through-hole penetrating both the inside and outside of the cover is formed in a portion of the cover in which the insertion portion is inserted into the insertion hole and a part of the mounting flange portion is opposed to the cover.
A nut made of metal (made of an iron-based alloy such as carbon steel) for supporting and fixing a part of the mounting flange portion to the cover with respect to the cover at the through-hole portion is included in the cover. It is fixed by engagement with the inner peripheral surface portion of the through hole or the peripheral portion of the through hole. Further, the holder is supported and fixed to the cover by screwing a bolt inserted through a through hole formed in a part of the mounting flange portion into the nut and further tightening.
In particular, in the rolling bearing unit with a rotational speed detecting device according to claim 1, the surface of the rolling member is galvanized before the nut is fixed to the through hole portion of the cover. . The cover is subjected to electrodeposition coating after the nut is fixed.

  According to a second aspect of the present invention, there is provided a method of manufacturing a rolling bearing unit with a rotational speed detecting device, wherein the through hole portion of the cover is formed on the surface of the nut so as to manufacture the rolling bearing unit with a rotational speed detecting device as described above. Before fixing to the galvanizing treatment. And after fixing this nut to the said cover, electrodeposition coating is given to this cover, without masking the internal thread part of this nut.

  According to the rolling bearing unit with a rotational speed detection device of the present invention configured as described above and the method for manufacturing the same, the electrodeposition coating is applied after the nut is fixed to the cover without masking the female thread portion of the nut. However, it is possible to make it difficult for paint by electrodeposition coating to adhere to the female thread portion of the nut. Therefore, even if the step of masking the female thread portion is omitted, the tightening operation of the nut and the bolt for fixing the holder is not difficult, and the rolling bearing unit with a rotation speed detecting device can be manufactured at low cost. realizable.

  That is, the nut is galvanized (including pre-treatment or post-treatment) before being fixed to the through-hole portion of the cover. For this reason, this nut is less likely to conduct electricity than the cover by the galvanized layer (including the pre-treatment or post-treatment layer) covering the surface. Therefore, when the nut is fixed to the cover and electrodeposition coating is applied, almost no electricity flows through the nut portion where it is difficult to conduct electricity, and the paint does not adhere to the nut portion or even if it adheres. . For this reason, it is possible to prevent the tightening operation between the nut and the bolt from becoming difficult. On the other hand, since sufficient paint adheres to the cover portion where electricity can be easily conducted, the anticorrosion property of the cover can be secured. In addition, the said nut can ensure corrosion resistance with the said zinc plating layer which coat | covered the surface.

  1 to 7 show a first embodiment of the present invention corresponding to claims 1 and 2. In the case of the rolling bearing unit with a rotational speed detection device of this embodiment, a hub 2 that is a rotating wheel that rotates during use is rotatably supported on the inner diameter side of the outer ring 1 that is a stationary wheel that does not rotate even when used. The rotational speed of the encoder 3 fixed to the inner end of the hub 2 in the axial direction can be detected by a sensor 4 (see FIG. 7) supported on the outer ring 1. On the inner peripheral surface of the outer ring 1 that is a stationary side circumferential surface, double-row outer ring raceways 5 and 5 that are stationary side tracks are provided. The hub 2 is a combination of a hub body 6 and an inner ring 7, and each of the outer peripheral surfaces of the hub 2, which is a rotation side peripheral surface, faces the outer ring raceways 5, 5. The inner ring raceways 8 and 8 are provided. A plurality of rolling elements 9 and 9 are provided between the inner ring raceways 8 and 8 and the outer ring raceways 5 and 5, respectively, so as to be freely rollable while being held by the cages 10 and 10, respectively. The hub 2 is rotatably supported inside the outer ring 1. In the case of a rolling bearing unit for automobiles that is heavy, tapered rollers may be used as the plurality of rolling elements 9, 9, instead of balls as shown.

  Further, in order to incorporate the rotational speed detection device into the rolling bearing unit as described above, the encoder 3 is fitted and fixed to the outer peripheral surface of the inner ring 7 at the inner end portion in the axial direction and away from the inner ring raceway 8. Yes. The encoder 3 includes a cored bar 11 and a permanent magnet 12 that are each formed in an annular shape. Among these, the permanent magnet 12 is magnetized in the axial direction, and the magnetization direction is changed alternately and at equal intervals in the circumferential direction. Therefore, the south pole and the north pole are alternately arranged at equal intervals on the inner surface in the axial direction of the permanent magnet 12, which is the detected surface.

  Further, a cover 13 coated with cationic electrodeposition coating, which will be described later, is fitted and fixed to the inner end opening of the outer ring 1 so as to face the inner surface in the axial direction of the permanent magnet 12 constituting the encoder 3. Yes. The cover 13 is formed by subjecting a mild steel plate such as SPCC to plastic processing such as drawing, and has a bottomed cylindrical shape in which the inner end in the axial direction of the cylindrical portion 14 is closed by the bottom plate portion 15. Further, the cover 13 is fixed to the inner end portion of the outer ring 1 in the axial direction by fitting the tip end portion of the cylindrical portion 14 to the inner end portion of the outer ring 1 in the axial direction. An insertion hole 16 and a through hole 17 are provided in the upper part of the bottom plate portion 15. The insertion hole 16 is for inserting the insertion portion 19 (see FIG. 7) of the holder 18 holding a sensor for detecting the rotational speed of the encoder 3, and is closer to the outer diameter of the bottom plate portion 15. A portion (upper end portion) is formed at a portion facing the encoder 3.

Further, the nut 20 that is fixed to the peripheral portion of the through hole 17 in the axially outer side surface of the bottom plate portion 15 is formed by projecting an annular projecting portion 21 on the axial end surface thereof. (See FIGS. 5 and 6). The outer diameter of the front half (axially inner half) 22 of the protruding portion 21 is larger than the outer diameter of the base half (axially outer half) 23, and the outer peripheral surface of the distal half 22 is The taper surface is a tapered surface inclined in a direction of decreasing toward the tip edge. Further, minute irregularities are formed on the outer peripheral surface of the tip half 22 by knurling. The outer diameter d ₂₂ in the free state of the distal end edge of the leading half ₂₂ is smaller than the inner diameter R _{17 in} the free state of the through hole 17, and the outer diameter D ₂₂ in the free state of the base end edge is Is larger than R ₁₇ (d ₂₂ <R ₁₇ <D ₂₂ ).

  In the case of this embodiment, before the nut 20 is fixed to the peripheral portion of the through hole 17, the nut 20 is subjected to galvanizing treatment (electrogalvanizing treatment). For this reason, this nut 20 has corrosion resistance by the galvanized layer which coat | covered the surface. In the galvanizing process, a process such as masking is not performed. However, the film thickness of the galvanized layer is limited, and the tightening operation between the nut 20 and the bolt 24 (see FIG. 7) for fixing the holder 18 to the cover 13 is a practical problem. You can do without.

  As described above, the nut 20 that has been subjected to the galvanizing treatment is, as shown in FIG. 6A, from the state in which the protruding portion 21 is opposed to the axially outer end side opening of the through hole 17. The bottom plate portion 15 is pressed strongly against the outer surface in the axial direction by a press machine or the like. As a result of the pressing operation, the protruding portion 21 is formed in the through hole 17 while plastically deforming the inner peripheral surface portion of the through hole 17 with a part of the bottom plate portion 15 as shown in FIG. Then, the bottom plate portion 15 is pushed in until the axially outer side surface of the bottom plate portion 15 comes into contact with the axially inner end surface of the main body portion of the nut 20. By this operation, the front half 22 of the protrusion 21 bites into the inner peripheral surface portion of the through hole 17, and the nut 20 surrounds the through hole 17 on the outer surface in the axial direction of the bottom plate portion 15 of the cover 13. Supported and fixed. In the case of this embodiment, the protrusion 21 has a surface hardness of about Hv550, which is sufficiently harder than the cover 13 made of SPCC material and having a hardness of about Hv100 to 130. Therefore, it is sufficiently possible that a part of the cover 13 is plastically deformed so that the protruding portion 21 bites into the inner peripheral surface portion of the through hole 17. In the case of this embodiment, the thickness of the bottom plate portion 15 is about 0.8 to 1.2 mm, but the axial dimension of the protruding portion 21 is appropriately set even with this thickness. By restricting, the nut 20 can be fixed to the bottom plate portion 15 without protruding the protruding portion 21 from the axially inner side surface of the bottom plate portion 15.

  Next, electrodeposition coating is applied to the cover 13 (and the nut 20 fixed to the cover 13) without masking the female thread portion 25 of the nut 20. In this embodiment, cationic electrodeposition coating (lead-free), which is a kind of electrodeposition coating, is applied. This electrodeposition coating is performed by immersing a product (in the present embodiment, the cover 13 in the present embodiment) to be coated (in order to improve anticorrosion) in a low-concentration aqueous solution containing a positively charged paint. This is done by passing a direct current between the counter electrode. In this case, the product side is a cathode and the counter electrode side is an anode. When a direct current continues to flow, the positively charged paint collects on the cathode side and forms a coating film on the surface of the cathode side. This coating film is made of an epoxy-based insoluble resin (polymer) and has corrosion resistance.

  As described above, when cationic electrodeposition is applied to the cover 13 and the nut 20 fixed to the cover 13, a large amount of paint adheres to the cover 13 portion constituting the cathode side. The paint hardly adheres to the nut 20 portion. The reason for this is as follows. That is, the nut 20 is galvanized before being fixed to the cover 13. For this reason, the nut 20 is less likely to conduct electricity than the cover 13 to which the nut 20 is fixed due to the galvanized layer including the pre-treatment or post-treatment layer covering the surface. Therefore, when a direct current is passed through the cover 13 and the nut 20 fixed to the cover 13 to perform cationic electrodeposition coating, almost no electricity flows through the nut 20 portion which is difficult to conduct electricity. For this reason, the paint does not adhere to the nut 20 (the female screw portion 25), or even if it adheres, it becomes extremely small. On the other hand, a lot of electricity flows through the cover 13 and the surface thereof is covered with the coating film having anticorrosion properties. Since this cover 13 may be exposed to rainwater or the like, the thickness of the coating film is regulated to enhance the corrosion resistance. In the case of the present embodiment, before applying the cationic electrodeposition coating, a zinc phosphate-based chemical conversion treatment is applied as a coating base treatment to improve the anticorrosion and paint adhesion.

  As described above, the holder 18 is supported and fixed on the top of the cover 13 that has been subjected to cationic electrodeposition coating, using the insertion hole 16, the through hole 17, and the nut 20. The holder 18 is formed by injection molding synthetic resin, and includes the insertion portion 19 and a mounting flange portion 26. Of these, the insertion portion 19 has a substantially columnar shape that can be freely inserted into the small cylindrical portion 27 formed at the peripheral edge of the insertion hole 16 without rattling. A sensor (sensor body) that changes the output in response to a change in the characteristics of the detected surface is held (embedded support) at the distal end of the insertion portion 19, facing the detected surface of the permanent magnet 12. )is doing. The mounting flange portion 26 is formed by connecting the base end portion to the base end portion (the inner end portion in the axial direction) of the insertion portion 19, and has a mounting hole 28 at the tip end portion. The pitch between the center of the mounting hole 28 and the center of the insertion portion 19 is equal to the pitch between the center of the insertion hole 16 and the center of the through hole 17. In addition, although the paint by the cationic electrodeposition coating adheres also to the inner peripheral surface of the small cylindrical portion 27, the seal between the inner peripheral surface and the outer peripheral surface of the insertion portion 19 is achieved by an O-ring. The allowable value of the dimensional difference between the inner diameter of the small cylindrical portion 27 and the outer diameter of the insertion portion 19 is relatively large. Therefore, it is not a problem that the paint adheres to the inner peripheral surface of the small cylindrical portion 27.

  When the holder 18 as described above is supported and fixed to the cover 13, the insertion portion 19 is inserted into the insertion hole 16 and the mounting hole 28 is aligned with the through-hole 17. Then, a bolt 24 inserted through the mounting hole 28 and the through hole 17 from the inner side to the outer side in the axial direction is screwed into the nut 20 and further tightened. In this state, the holder 18 is supported and fixed to the cover 13, and the sensor held at the distal end portion of the insertion portion 19 comes close to and faces the detection surface of the permanent magnet 12 through an appropriate gap.

  When the rolling bearing unit with a rotational speed detection device according to the invention as described above is used, the stationary side flange 29 fixed to the outer peripheral surface of the outer ring 1 is coupled and fixed to the suspension device with a bolt (not shown), and By fixing the wheel to the rotation side flange 30 fixed to the outer peripheral surface of the hub 2 by a plurality of studs 31 provided on the rotation side flange 29, 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 existing on the detected surface of the permanent magnet 12 pass alternately through the vicinity of the sensor held at the tip of the insertion portion 19. As a result, the characteristics of the magnetic detection elements such as the Hall IC and the magnetoresistive element constituting the sensor change, and the output of the sensor changes. The frequency at which the sensor output changes in this way is proportional to the rotational speed of the wheel. Therefore, if the output of this sensor is sent to a controller (not shown), the ABS and TCS can be controlled appropriately.

  In the case of the rolling bearing unit with the rotational speed detection device of the present embodiment configured and operated as described above, the nut 20 is fixed to the cover 13 without masking the female thread portion 25 of the nut 20. Then, even if a cationic electrodeposition coating is applied thereafter, the paint can hardly adhere to the female thread portion 25 of the nut 20. Therefore, even if the step of masking the female screw portion 25 is omitted, the tightening operation between the nut 20 and the bolt 24 for fixing the holder 18 does not become difficult. In addition, a rolling bearing unit with a rotation speed detecting device that can accurately mount the holder 18 at a predetermined position and accurately detect the rotation speed can be realized at low cost. Further, in this embodiment, rain water or the like that has entered the cover 13 during rainy weather driving or car washing can be discharged to the outside through a drain hole 32 provided in the cover 13. For this reason, the rainwater or the like does not collect in the cover 13, and further, the rust is prevented by the rust prevention effect of the coating film and the galvanized layer by the cationic electrodeposition coating, which covers the cover 13 and the nut 20, respectively. There is no rusting.

8 and 9 show a second embodiment of the present invention. In the case of the present embodiment, the outer peripheral surface shape of the protruding portion 21a formed to protrude from the inner end surface in the axial direction of the nut 20a is inclined in a direction in which the outer diameter increases toward the end edge (the inner end edge in the axial direction). Tapered surface. Outer diameter d _21a of a free state of such protrusion 21a is equal to the inner diameter R ₁₇ in the free state of the through-hole 17, slightly smaller than the inner diameter R ₁₇ (d _21a ≦ R _17). When the nut 20a provided with such a protruding portion 21a is fixed to the outer surface in the axial direction of the bottom plate portion 15 of the cover 13, first, as shown in FIG. Insert into the through hole 17. Next, the nut 20a is strongly pressed against the bottom plate portion 15 by a press machine or the like. By this pressing operation, as shown in FIG. 9B, the axially inner end portion of the main body portion of the nut 20a, which is a regular hexagon that is a kind of polygon, is penetrated in the bottom plate portion 15. It sinks into the periphery of the hole 17. At the same time, the meat at the peripheral edge of the through-hole 17 is displaced inward in the radial direction and bites into the base end of the protrusion 21a. As a result, the nut 20a does not rotate with respect to the bottom plate portion 15 when the bolt 24 (see FIG. 7) is tightened (because the regular hexagonal portion bites into the bottom plate portion 15). Fixed to the joint. Since the configuration and operation of the other parts are the same as those in the first embodiment described above, the illustration and description regarding the equivalent parts are omitted.

FIG. 10 shows a third embodiment of the present invention. In the case of the present embodiment, a general nut having no projecting portion or the like is used as the nut 20b. Instead, a plurality of tongue pieces 33 (33 in the illustrated example) are bent and formed around the through hole 17 a formed in the bottom plate portion 15 of the cover 13. Each of the tongue pieces 33, 33 is provided at the peripheral edge of the through hole 17 a, one set of two in a state extending radially outward from the peripheral edge of the through hole 17 a, for a total of three sets of six slits 34. , 34 are bent at a right angle outward in the axial direction. The nut 20b is configured such that each of the tongue pieces 33, the portion closer to the outer diameter of the inner end surface in the axial direction abuts the peripheral portion of the through hole 17a in the outer surface in the axial direction of the bottom plate portion 15. The outer peripheral surface and the axially outer end surface are held down by 33 so as to be fixedly coupled to the bottom plate portion 15.
Since the configuration and operation of the other parts are the same as in any of the first and second embodiments described above, the illustration and description regarding the equivalent parts are omitted.

Sectional drawing which shows Example 1 of this invention in the state which abbreviate | omitted the sensor. Sectional drawing which similarly extracts and shows the state which supported and fixed the nut with respect to the cover. Similarly, the figure seen from the right side of FIG. Similarly, BB sectional drawing of FIG. The perspective view which shows the nut similarly supported and fixed to a cover. The enlarged sectional view equivalent to the A section of Drawing 1 showing the state where this nut is supported and fixed to a cover in order of a process. Sectional drawing equivalent to the upper right part of FIG. 1 which shows the state which assembled | attached the sensor to the said cover similarly. The perspective view similar to FIG. 5 which shows Example 2 of this invention. Similarly, the expanded sectional view similar to FIG. 6 which shows the state which supports and fixes this nut to a cover in order of a process. The perspective view similar to FIG. 5 which shows Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Encoder 4 Sensor 5 Outer ring raceway 6 Hub body 7 Inner ring 8 Inner ring raceway 9 Rolling element 10 Cage 11 Core metal 12 Permanent magnet 13 Cover 14 Cylindrical part 15 Bottom plate part 16 Insertion hole 17, 17a Through hole 18 Holder 19 Insertion part 20, 20a, 20b Nut 21, 21a Projection part 22 First half part 23 Base half part 24 Bolt 25 Female thread part 26 Mounting flange part 27 Small cylindrical part 28 Mounting hole 29 Static side flange 30 Rotating side flange 31 Stud 32 Water drainage Hole 33 Tongue piece 34 Slit

Claims (2)

  A stationary wheel that has a stationary side track on the stationary side circumferential surface and does not rotate during use, a rotating wheel that has a rotational side track on the rotating side circumferential surface opposite to the stationary side circumferential surface and rotates during use, and A plurality of rolling elements provided between the rotating side track and the stationary side track so as to be freely rollable, and characteristics of the detected surface fixed concentrically to the rotating wheel on a part of the rotating wheel. The encoder is alternately changed with respect to the circumferential direction, a metal cover fixed to a part of the stationary wheel, an insertion hole provided in a part of the cover, and a state where the insertion hole is inserted. A sensor that is supported by a part of the cover and that changes an output as the encoder rotates.The sensor is held by a holder, and the holder holds the sensor in the insertion hole. Rotation with insertion section and mounting flange section for insertion In a rolling bearing unit with a degree detection device, a through-penetration that penetrates both the inner and outer surfaces of the cover in a portion of the cover that faces the part of the mounting flange portion in a state where the insertion portion is inserted into the insertion hole. A hole is formed, and a metal nut for supporting and fixing a part of the mounting flange portion to the cover with respect to the cover at the through-hole portion is an inner periphery of the through-hole in the cover. A bolt that is fixed by engagement with a surface portion or a peripheral portion of the through-hole and that is inserted through a through-hole formed in a part of the mounting flange is screwed into the nut and further tightened, whereby the holder is fixed. The nut is supported and fixed to the cover, and the nut is galvanized on the surface before being fixed to the through hole portion of the cover. Speed sensing rolling bearing unit, characterized in that those having been subjected to electrodeposition coating after.   A stationary wheel that has a stationary side track on the stationary side circumferential surface and does not rotate during use, a rotating wheel that has a rotational side track on the rotating side circumferential surface opposite to the stationary side circumferential surface and rotates during use, and A plurality of rolling elements provided between the rotating side track and the stationary side track so as to be freely rollable, and characteristics of the detected surface fixed concentrically to the rotating wheel on a part of the rotating wheel. The encoder is alternately changed with respect to the circumferential direction, a metal cover fixed to a part of the stationary wheel, an insertion hole provided in a part of the cover, and a state where the insertion hole is inserted. A sensor that is supported by a part of the cover and that changes an output as the encoder rotates.The sensor is held by a holder, and the holder holds the sensor in the insertion hole. An insertion portion to be inserted and a mounting flange portion; Among these, in the state where the insertion portion is inserted into the insertion hole, a part of the mounting flange portion is opposed to a through hole that penetrates both the inner and outer surfaces of the cover. A metal nut for supporting and fixing a part of the mounting flange portion to the cover is engaged with the inner peripheral surface portion of the through hole or the peripheral portion of the through hole in the cover. A bolt with a rotational speed detection device in which the holder is supported and fixed to the cover by screwing the bolt into the nut and tightening the bolt, which is fixed by the bolt and inserted through the through hole formed in a part of the mounting flange portion. A method for manufacturing a bearing unit, wherein the surface of the nut is subjected to galvanization before being fixed to the through-hole portion of the cover, and then the nut is fixed to the cover. Of without masking is formed on the female screw portion of the nut, method of manufacturing the rolling bearing unit for performing electrodeposition coating on the cover.

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