CN211820436U - Bearing cap with sensor unit and hub unit bearing - Google Patents

Abstract

The utility model relates to a bearing cap with a sensor unit in which a sensor unit is mounted on a bearing cap for closing an opening part constituting an outer ring of a hub unit bearing, and a hub unit bearing having the bearing cap. The O-ring is arranged in a radially compressed state between the inner peripheral surface of the axially intermediate portion of the cage insertion hole and the outer peripheral surface of the axially intermediate portion of the cage shaft portion. On the inner peripheral surface of the cage insertion hole, an annular recessed portion is provided over the entire circumference in a range from the axially inner opening to a position adjacent to the axially inner side of the arrangement position (P) of the O-ring. The inner diameter of the annular recessed portion is larger than the outer diameter of the O-ring fitted to the cage shaft portion before being inserted into the cage insertion hole. With this configuration, not only can the sealability between the holder insertion hole and the holder shaft portion be ensured, but also the sensor holder can be attached well, and the thickness of the bottom of the holder insertion hole can be reduced to achieve rotational speed detection. Improved accuracy.

Description

Bearing cap with sensor unit and hub unit bearing

technical field

The utility model relates to a bearing cap with a sensor unit in which a sensor unit is mounted on a bearing cap for closing an opening part of an outer ring constituting a hub unit bearing, and a hub unit bearing having the bearing cap with the sensor unit.

Background technique

Conventionally, a rotational speed detection device for detecting the rotational speed of the wheel necessary for control of ABS and the like is combined with a hub unit bearing for rotatably supporting a wheel of an automobile or the like with respect to a suspension device. Patent Document 1 describes a structure in which an annular encoder constituting a rotational speed detection device is supported on an axially inner portion of a hub constituting a hub unit bearing, and in the axial direction of an outer ring constituting the hub unit bearing A sensor unit that constitutes a rotational speed detection device is mounted on the bearing cap with the inner opening closed.

In the conventional structure, a cage insertion hole penetrating in the axial direction is provided in a portion of the bearing cover that is axially opposed to a portion of the encoder in the circumferential direction. In addition, a holder shaft portion for holding the sensor at the distal end portion is inserted into the holder insertion hole. Thereby, the detection portion of the sensor and the detection surface of the encoder are brought close to and opposed to each other. In addition, an O-ring made of an elastic material is sandwiched between the outer peripheral surface of the holder shaft portion and the inner peripheral surface of the holder insertion hole.

However, the hub unit bearing of the structure described in Patent Document 1 is used in a bad muddy water environment, and when the sealing performance by the O-ring is insufficient, muddy water may pass through the cage insertion hole which is a through hole and cause Intrusion into the space inside the bearing cap.

Patent Document 2 describes a structure in which the holder insertion hole is a bottomed hole, whereby the sensor faces the encoder across the bottom of the holder insertion hole. According to this configuration, it is possible to effectively prevent foreign matter such as muddy water from passing through the cage insertion hole and intruding into the space inside the bearing cap.

However, in the structure described in Patent Document 2, when the moisture intruding between the cage insertion hole and the cage shaft portion freezes, there is a possibility that the bottom of the cage insertion hole is damaged. Therefore, it is necessary to secure the strength of the bottom portion of the holder insertion hole, and it is difficult to make the thickness of the bottom portion of the holder insertion hole thin. As a result, the distance (air cap) between the detection part of the sensor and the detection surface of the encoder increases, and the amount of magnetic flux that enters and leaves the detection surface of the encoder and passes through the detection part of the sensor decreases. There is a possibility that the accuracy of the rotational speed detection based on the sensor is reduced.

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2013-53638

Patent Document 2: Japanese Patent Laid-Open No. 2016-136064

Utility model content

An object of the present invention is to provide a structure of a bearing cap with a sensor unit in order to solve the above-mentioned problems, which can not only ensure the sealing performance between the cage insertion hole and the cage shaft part, but also make the cage The thickness of the bottom portion of the insertion hole is reduced to improve the rotational speed detection accuracy.

In order to solve the above-mentioned problems, the bearing cover with a sensor unit of the present invention includes a bearing cover, a sensor unit, and an elastic ring. The bearing cap has a bottomed cylindrical shape, is attached to an axially inner portion of an outer ring that is rotatably supported to a hub having an encoder, and closes an axially inner opening of the outer ring. In addition, the bearing cap has a fitting cylindrical portion that is fitted and fixed to the outer ring, and a bottom plate portion made of synthetic resin that closes the inner diameter side of the fitting cylindrical portion, and the bottom plate portion is at a portion facing a part of the encoder in the axial direction A cage insertion hole with a bottom hole opened only on the inner side in the axial direction is provided. The sensor unit includes a sensor holder having a holder shaft portion inserted into the holder insertion hole, and a sensor held by a distal end portion of the holder shaft portion, which is attached to the bearing cap and a sensor holder. The elastic ring is arranged in a radially compressed state between the inner peripheral surface of the axially intermediate portion of the cage insertion hole and the outer peripheral surface of the axially intermediate portion of the cage shaft portion.

In the present invention, there is further provided a bearing cap with a sensor unit, wherein the cage insertion hole is opened in at least a part of the circumferential direction of the inner peripheral surface from the inner side in the axial direction to the position where the elastic ring is arranged on the inner side in the axial direction There is a degassing portion within the range of the adjacent position, and the inner radius of the degassing portion is larger than the outer radius of the elastic ring fitted to the cage shaft portion before being inserted into the cage insertion hole.

The wheel hub unit bearing of the utility model has: an outer ring with an outer ring raceway on the inner peripheral surface; a wheel hub with an inner ring raceway on the outer peripheral surface; a plurality of rolling bodies arranged between the outer ring raceway and the inner ring raceway ; an encoder supported on an axially inner portion of the hub coaxially with the hub; a bearing cap mounted on an axially inner portion of the outer ring; and a sensor unit mounted on the bearing cap.

In the hub unit bearing of the present invention, a bearing cover with a sensor unit in which a sensor unit is mounted on the bearing cover is provided as the bearing cover with a sensor unit of the present invention.

According to the present invention, not only can the sealing performance between the cage insertion hole and the cage shaft portion be ensured, but also the mounting workability of the sensor cage to the bearing cap can be improved, and the thickness of the bottom of the cage insertion hole can be changed. It is thin and seeks to improve the rotation speed detection accuracy.

Description of drawings

FIG. 1 is a cross-sectional view of a hub unit bearing with a rotational speed detection device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of the vicinity of the holder insertion hole of FIG. 1 .

3 is a cross-sectional view showing a bearing cap removed from the hub unit bearing with a rotational speed detection device according to the first embodiment.

FIG. 4 is a view of the bearing cap viewed from the left side of FIG. 3 .

FIG. 5 is a view of the bearing cap as viewed from the right side of FIG. 3 .

6(A) is a diagram illustrating an early stage in which the O-ring is present on the inner diameter side of the tapered surface for explaining the step of inserting the cage shaft portion with the O-ring fitted to the cage insertion hole.

6(B) is a diagram illustrating a middle stage in which the O-ring is present on the inner diameter side of the guide tapered surface for explaining the step of inserting the cage shaft portion with the O-ring fitted to the cage insertion hole.

6(C) is a diagram illustrating a later stage in which the O-ring is present on the inner diameter side of the support cylindrical surface for explaining the step of inserting the cage shaft portion with the O-ring fitted to the cage insertion hole.

7 is an enlarged view of the vicinity of the holder insertion hole according to the second embodiment of the present invention.

8 is an enlarged view of the vicinity of the holder insertion hole according to the third embodiment of the present invention.

Detailed ways

The first embodiment will be described with reference to FIGS. 1 to 6 .

The hub unit bearing 8 of the present embodiment rotatably supports the wheel relative to the suspension device, detects the rotational speed of the wheel, and has an outer ring 9, a hub 10 that rotates with the wheel, a plurality of rolling elements 11, an outer seal member 12, The bearing cover 13, the rotational speed detection device 14, and the O-ring 15 which is an elastic ring.

In addition, regarding the hub unit bearing 8 , the axially outer side is the left side of FIGS. 1 to 3 and FIG. 6 which is the outer side in the width direction of the vehicle in the state assembled to the vehicle, and the axially inner side is the outer side of the vehicle in the state of being assembled to the vehicle. The right side of FIGS. 1 to 3 and FIG. 6 on the center side in the width direction of the vehicle.

The outer ring 9 has a plurality of rows of outer ring raceways 16a and 16b on the inner peripheral surface, and has a stationary flange 17 on the outer peripheral surface. The stationary flange 17 is provided in the axial middle portion of the outer ring 9 so as to protrude radially outward. The outer ring 9 is used for fixing the stationary flange 17 to a suspension device such as a steering knuckle, and does not rotate in a use state. The outer ring 9 is made of medium carbon steel such as S53C, for example.

The hub 10 is disposed on the inner diameter side of the outer ring 9 coaxially with the outer ring 9 , and is configured by combining the hub ring 18 and the inner ring 19 . The hub ring 18 is a shaft member that fits and holds the inner ring 19 , and has a shaft portion 20 and a rotating flange 21 . The shaft portion 20 is provided in a range from an axially inner portion to an axially intermediate portion of the hub wheel 18 . The shaft portion 20 has a small-diameter stepped portion 22 on the inner side in the axial direction for fitting the inner ring 19 to the outside, and has inner ring raceways 23 a arranged on the outer side in the axial direction on the outer peripheral surface of the intermediate portion in the axial direction. A caulking portion 24 bent radially outward is formed on an axially inner portion of the shaft portion 20 , and the caulking portion 24 presses the axially inner end surface of the inner ring 19 . The rotating flange 21 protrudes radially outward from an axially outer portion of the hub wheel 18 adjacent to the axially outer side of the shaft portion 20 , and has a substantially circular ring shape. The inner ring 19 is externally fitted to the small-diameter stepped portion 22 of the hub wheel 18, and has inner ring raceways 23b arranged on the inner side in the axial direction on the outer peripheral surface. In the hub 10, a rim constituting a wheel and a rotating body for braking are fixed to the rotating flange 21, and are rotated during use. The hub ring 18 is made of medium carbon steel such as S53C, for example, and the inner ring 19 is made of high carbon chromium bearing steel such as SUJ2, for example.

The rolling elements 11 are rotatably held by cages not shown, and are arranged between the plurality of rows of outer ring raceways 16a and 16b and the plurality of rows of inner ring raceways 23a and 23b. Thereby, the hub 10 is rotatably supported on the inner diameter side of the outer ring 9 .

Grease (not shown) is sealed in the space 25 in which the plurality of rolling elements 11 are provided between the inner peripheral surface of the outer ring 9 and the outer peripheral surface of the hub 10 . In addition, in order to prevent the grease enclosed in the space 25 from leaking to the outside and prevent foreign matter such as muddy water from entering the space 25 , the axially outer opening of the space 25 is closed by the outer seal member 12 . On the other hand, a bottomed cylindrical bearing cap 13 is attached to the axially inner portion of the outer ring 9 to close the axially inner opening of the outer ring 9 .

The bearing cap 13 is constituted by a substantially disc-shaped cap body 26 made of synthetic resin, a metal ring 27 and a nut 28 that are molded and fixed to the cap body 26, and has a substantially cylindrical fitting cylinder portion 29, and a A substantially disk-shaped bottom plate portion 30 that is closed on the inner diameter side of the cylindrical joint portion 29 .

The cover main body 26 is manufactured by injection molding (axial stretch molding) of synthetic resin. As the synthetic resin constituting the cover body 26, for example, a fiber-reinforced polyamide resin material obtained by appropriately adding glass fibers to polyamide 66 resin can be used. In addition, if necessary, amorphous aromatic polyamide resins (modified polyamide 6T/6I), low water-absorbing aliphatic polyamide resins (polyamide 11 resin, polyamide 12 resin, polyamide 610 resin, polyamide 612 resin) to improve water resistance.

A metal ring 27 made of stainless steel sheet, rolled steel sheet, or the like is molded and fixed to the radially outer portion of the lid body 26 . The metal ring 27 has a substantially L-shaped cross-sectional shape, and includes a cylindrical portion 31 and an outward flange portion 32 bent from an axially inner portion of the cylindrical portion 31 to a radially outer portion. The cylindrical portion 31 protrudes from the radially outer portion of the cover main body 26 to the axially outer side, and constitutes the fitting cylindrical portion 29 of the bearing cover 13 . The outward flange portion 32 is embedded inside the radially outer portion of the cover main body 26 . On the axially outer surface of the radially outer portion of the cover main body 26 , the locking groove 33 is formed over the entire circumference. An O-ring 34 is locked in the locking groove 33 .

The portion of the cover body 26 that exists radially inward from the portion in which the metal ring 27 is molded closes the inner diameter side of the metal ring 27 , and constitutes the bottom plate portion 30 of the bearing cover 13 . The bottom plate portion 30 has a thickened portion 35 whose thickness (wall thickness) in the axial direction is larger than that of other portions. The thickened portion 35 is provided at a portion located above the bottom plate portion 30 in the vertical direction and at the center in the front-rear direction when the hub unit bearing 8 is assembled to the vehicle.

In the upper part of the thickened portion 35 and at a portion facing in the axial direction from a part of the detected surface of the encoder 42 to be described later, there is provided a cage insertion hole 36 which is a bottomed hole and opens only on the inner side in the axial direction. . The inner portion of the holder insertion hole 36 is closed by the bottom portion 37 . On the radially inner side of the thickened portion 35, a bag-shaped nut 28 is molded and fixed. The nut 28 has a female screw portion 38 formed on the inner peripheral surface, and an engaging groove 39 is formed on the outer peripheral surface. A part of the synthetic resin constituting the thickened portion 35 protrudes inside the engaging groove 39 . In a radially intermediate portion of the thickened portion 35 and a portion sandwiched between the cage insertion hole 36 and the nut 28, a cutout portion 40 that is opened only on the outer side in the axial direction is provided.

On the axially outer surface of the bottom plate portion 30, a plurality of ribs 41a and 41b are provided. The rib 41 a has a flat plate shape, and is provided so as to extend in the radial direction from the center portion of the bottom plate portion 30 . The rib 41b has a cylindrical shape, and is arranged coaxially with the bottom plate portion 30 .

The bearing cap 13 as described above is attached to the shaft of the outer ring 9 by inserting the fitting cylindrical portion 29 composed of the cylindrical portion 31 of the metal ring 27 into the axially inner portion of the outer ring 9 with an interference fit. to the inside. In addition, positioning of the bearing cap 13 relative to the outer ring 9 in the axial direction is achieved by abutting the axially outer surface of the radially outer portion of the cap body 26 with the axially inner end surface of the outer ring 9 . Furthermore, by elastically sandwiching the O-ring 34 between the axially inner end face of the outer ring 9 and the bottom face of the locking groove 33 of the cap body 26 , foreign matter such as moisture is prevented from being released from the radially outer portion of the cap body 26 . The contact portion between the axially outer surface and the axially inner end surface of the outer ring 9 penetrates and penetrates into the inner side of the bearing cap 13 .

The rotational speed detection device 14 includes an encoder 42 and a sensor unit 43 .

The encoder 42 has an annular shape, and is supported and fixed to an outer peripheral surface of an axially inner portion of the inner ring 19 constituting the hub 10 in a state of being coaxial with the hub 10 . The encoder 42 has a support ring 44 and an encoder body 45 . The support ring 44 is made of a magnetic metal plate, and is manufactured by pressing. The support ring 44 has a substantially L-shaped cross-sectional shape, and is externally fitted and fixed to the axially inner portion of the inner ring 19 by an interference fit. The encoder main body 45 is made of a permanent magnet such as a rubber magnet or a plastic magnet in which a magnetic substance such as ferrite powder is mixed, and is fixed to the axial inner surface of the support ring 44 . On the axial inner surface of the encoder body 45 , that is, the detected surface, S poles and N poles are alternately arranged at equal intervals in the circumferential direction.

The sensor unit 43 is attached to the bearing cover 13 and has a sensor holder 46 and a sensor 47 made of synthetic resin. The sensor holder 46 has a cylindrical (rod-shaped) holder shaft portion 48 and a mounting flange portion 49 provided on the proximal end side of the holder shaft portion 48 . The outer diameter of the cage shaft portion 48 is not changed in the axial direction except for the portion where the locking groove 51 described later is formed. The sensor 47 is composed of a magnetic detection element such as a Hall IC, a Hall element, an MR element, and a GMR element, and an IC incorporating a waveform shaping circuit, and is held (molded) on the distal end of the holder shaft portion 48 .

The sensor unit 43 is mounted by screwing the male screw portion of a bolt (not shown) inserted into the through hole 50 of the mounting flange portion 49 and the female screw portion 38 of the nut 28 molded on the bottom plate portion 30 . on the bearing cap 13. In this mounted state, the holder shaft portion 48 is inserted into the inner side of the holder insertion hole 36 . In addition, the sensor 47 held by the distal end of the holder shaft portion 48 is axially opposed to the detected surface of the encoder 42 (encoder body 45 ) via the bottom portion 37 of the holder insertion hole 36 .

In order to ensure the sealing performance between the cage insertion hole 36 and the cage shaft portion 48 , the O-ring 15 is compressed in the radial direction, that is, the inner peripheral surface of the cage insertion hole 36 and the retaining The outer peripheral surface of the cage shaft portion 48 is disposed between the inner peripheral surface of the axially intermediate portion of the cage insertion hole 36 and the outer peripheral surface of the axially intermediate portion of the cage shaft portion 48 in a state where the outer peripheral surface has an interference. In the present embodiment, the O-ring 15 is externally fitted (locked) to form a An annular locking groove 51 having a substantially rectangular cross-sectional shape is formed on the outer peripheral surface of the intermediate portion in the axial direction of the holder shaft portion 48 . The O-ring 15 is made of, for example, an elastic material such as rubber, has a substantially circular cross-sectional shape in a free state, and has a wire diameter larger than the groove depth of the locking groove 51 . In addition, the arrangement position P of the O-ring 15 refers to the axial position at which the center of the O-ring 15 is located in a state in which the insertion operation of the cage shaft portion 48 is completed.

In the present embodiment, when the cage shaft portion 48 having the O-ring 15 fitted therein is inserted into the cage insertion hole 36 , the cage is not caused to be released in order to release the air inside the cage insertion hole 36 to the outside. The air inside the insertion hole 36 is excessively compressed, and the shape of the inner peripheral surface of the cage insertion hole 36 is improved.

Specifically, the range from the axially outer part to the middle part including the arrangement position P of the O-ring 15 in the inner peripheral surface of the cage insertion hole 36 is set as a support circle whose inner diameter does not change in the axial direction Cylinder surface 52. In addition, the inner diameter d52 of the support cylindrical surface 52 is set to be slightly larger than the outer diameter D48 of the holder shaft portion 48 and before the insertion of the O-ring 15 externally fitted to the holder shaft portion 48 to the holder insertion hole 36 The outer diameter D15 (hereinafter referred to as "outer diameter D15 of the ring before reducing the diameter". Refer to Fig. 6(A)) is small (D48<d52<D15). Thereby, the O-ring 15 can be compressed in a state in which the O-ring 15 is arranged on the inner diameter side of the support cylindrical surface 52 , and the front side portion of the holder shaft portion 48 is prevented from being placed on the support cylindrical surface 52 . Shaking inside.

In addition, the inner diameter d53 ratio is provided over the entire circumference in the range from the axially inner opening to the position adjacent to the axially inner side of the arrangement position P of the O-ring 15 in the inner peripheral surface of the cage insertion hole 36 . The ring-shaped concave portion 53 serving as the outgassing portion has a larger outer diameter D15 (inner radius d53/2 is the outer radius D15/2 of the O-ring 15 ) before the diameter reduction. In addition, the bottom surface (inner peripheral surface) of the annular recessed portion 53 is a tapered surface 54 inclined in a direction in which the inner diameter becomes larger toward the axially inner side (the opening side of the cage insertion hole 36 ). In addition, the axial length (depth from the opening) of the annular recessed portion 53 (tapered surface 54 ) is determined by the relationship with the arrangement position P of the O-ring 15 , but it can be, for example, the retainer insertion hole 36 about 20% to 40% of the axial depth. In addition, regarding the inclination angle of the tapered surface 54, since the wall thickness (outer wall) around the retainer insertion hole 36 is thin, it is not possible to give an excessively steep inclination. From the viewpoint that the outer diameter of the O-ring 15 of the locking groove 51 of the holder shaft portion 48 is larger than the outer diameter, the holder shaft portion 48 to which the O-ring 15 is locked can be smoothly inserted into the holder insertion hole 36 From the viewpoint of, and from the viewpoint of giving a sufficient compression amount to the O-ring 15 after the insertion operation of the cage shaft portion 48 is completed, it can be set to, for example, about 0.5° to 5°.

In addition, a guide tapered surface 55 is provided in an axially intermediate portion of the inner peripheral surface of the cage insertion hole 36 and in a portion between the support cylindrical surface 52 and the tapered surface 54 . The guide tapered surface 55 is a portion that abuts the outer peripheral surface of the O-ring 15 to which the holder shaft portion 48 is fitted when the holder shaft portion 48 is inserted into the holder insertion hole 36 as described later. It has the same inclination angle as the tapered surface 54 , and continues smoothly with the tapered surface 54 . The inner diameter d55 of the guide tapered surface 55 decreases toward the axially outer side. That is, the axially outer portion of the guide tapered surface 55 is connected to the support cylindrical surface 52 , and the inner diameter d55 of the axially outer end portion is the same as the inner diameter d52 of the support cylindrical surface 52 . On the other hand, the guide tapered surface 55 is connected to the tapered surface 54 at the inner portion in the axial direction, and the inner diameter d55 of the inner end portion in the axial direction is the same as the outer diameter D15 of the ring before reducing the diameter. In addition, the inclination angle of the guide tapered surface 55 and the inclination angle of the tapered surface 54 can also be made different.

According to the hub unit bearing 8 of the present embodiment as described above, the wheel can be rotatably supported with respect to the suspension device, and the rotational speed of the wheel can be detected.

In particular, in the present embodiment, not only the sealing performance between the holder insertion hole 36 and the holder shaft portion 48 can be ensured, but also the mounting workability of the sensor holder 46 to the bearing cap 13 can be improved, and the holder can be inserted The thickness of the bottom portion 37 of the hole 36 is reduced to improve the rotational speed detection accuracy by the sensor 47 .

That is, the O-ring 15 is arranged with an interference between the inner peripheral surface of the axially intermediate portion of the cage insertion hole 36 and the outer peripheral surface of the axially intermediate portion of the cage shaft portion 48 . This can prevent the intrusion of moisture to the inner side (axially outer side) of the portion holding the O-ring 15 . Therefore, it is possible to prevent the bottom portion 37 of the holder insertion hole 36 from being damaged due to freezing of moisture.

6(A) , FIG. 6(B) , and FIG. 6(C) showing the installation work of the sensor holder 46 in the order of the steps will be specifically described as to how to make the installation workability of the sensor holder 46 good and to use The reason is that the thickness of the bottom portion 37 of the holder insertion hole 36 is reduced to improve the rotational speed detection accuracy by the sensor 47 .

As shown in FIG. 6(A) , when the holder shaft portion 48 having the O-ring 15 fitted to the outside is inserted into the holder insertion hole 36 , the O-ring 15 is located on the bottom surface of the annular recessed portion 53 , that is, the cone. In the stage on the inner diameter side of the shaped surface 54 , a gap 56 can be provided between the outer peripheral surface of the O-ring 15 and the tapered surface 54 . Accordingly, when the cage shaft portion 48 is further inserted until the outer peripheral surface of the O-ring 15 abuts against the guide tapered surface 55 as shown in FIG. 6(B), the cage insertion hole 36 can be The air inside is released to the outside through the gap 56 . In addition, since the tapered surface 54 is provided to a position adjacent to the axially inner side of the arrangement position P of the O-ring 15, as shown in FIG. 6(B) → FIG. The insertion amount of the holder shaft portion 48 is sufficiently short until the guide tapered surface 55 abuts and moves to the arrangement position P. Therefore, the air inside the holder insertion hole 36 can be prevented from being excessively compressed. Thereby, the holder shaft portion 48 can be prevented from being pushed back, and the mounting workability of the sensor holder 46 can be improved. In addition, since it is not necessary to increase the strength (thickness) of the bottom portion 37 of the cage insertion hole 36 in order to withstand the compressed air pressure, the thickness of the bottom portion 37 can be made thin, and the rotational speed detection accuracy by the sensor 47 can be achieved. improve.

In addition, the tapered surface 54 has a function of guiding (inducing) the distal end portion of the holder shaft portion 48 , whereby the holder shaft portion 48 can be smoothly inserted into the opening of the holder insertion hole 36 . Furthermore, the O-ring 15 passing through the tapered surface 54 can be gradually reduced in diameter by the guide tapered surface 55 having the same inclination angle as the tapered surface 54 . Thereby, the O-ring 15 can be smoothly pushed into the inner diameter side of the support cylindrical surface 52 . Therefore, also from this point, the attachment workability of the sensor holder 46 can be improved.

The second embodiment will be described with reference to FIG. 7 .

In the present embodiment, the inner peripheral surface of the retainer insertion hole 36 a is provided over the entire circumference in a range from the axially inner opening to the position adjacent to the axially inner side of the arrangement position P of the O-ring 15 . There is an annular recessed portion 53a having an inner diameter d53a larger than the outer diameter D15 of the ring before reducing the diameter (inner radius d53a/2 is the outer radius D15/2 of the O-ring 15). Moreover, the bottom surface (inner peripheral surface) of the annular recessed part 53a is made into the cylindrical surface 57 whose inner diameter is fixed in the axial direction. Furthermore, the support cylindrical surface 52 and the cylindrical surface 57 are made to be continuous via the level difference surface 58 .

In the case of the present embodiment as described above, when the holder shaft portion 48 to which the O-ring 15 is fitted is inserted into the holder insertion hole 36a, the O-ring can be inserted as indicated by the two-dot chain line. A gap 56 is provided between the outer peripheral surface of the ring 15 and the bottom surface of the annular recessed portion 53 a, that is, the cylindrical surface 57 . Thereby, the air inside the holder insertion hole 36a can pass through this clearance gap 56, and can be released to the outside. Furthermore, if the inner diameter d53a of the cylindrical surface 57 is slightly larger than the outer diameter D15 of the ring before reducing the diameter, the cylindrical surface 57 can also be used for centering the O-ring 15 (retainer insertion). The centering surface of the hole 36a and the cage shaft portion 48).

In addition, the support cylindrical surface 52 and the cylindrical surface 57 can also be made to be continuous by a guide tapered surface whose inner diameter becomes smaller as it goes to the outside in the axial direction, or by having a circular arc, as in the structure of the first embodiment. The convex surface of the cross-sectional shape is continuous.

The other configurations and effects are the same as those of the first embodiment.

The third embodiment will be described with reference to FIG. 8 .

In the present embodiment, a portion of the inner peripheral surface of the retainer insertion hole 36b in the circumferential direction extends from the axially inner opening to the position adjacent to the axially inner side of the arrangement position P of the O-ring 15, and the A groove 59 extending in the axial direction is provided in a state of being recessed radially outward. The inner radius d53b of the groove 59 is larger than the outer radius D15/2 of the elastic ring 15 fitted to the cage shaft portion 48 before being inserted into the cage insertion hole 36b. In addition, the bottom surface of the groove 59 is a partial cylindrical surface 57a having a constant inner diameter in the axial direction. Furthermore, the support cylindrical surface 52 and the partial cylindrical surface 57a are made to be continuous through the level difference surface 58a. In addition, the relaxation portion (continuous portion) between the support cylindrical surface 52 and the stepped surface 58a and the relaxation portion between the circumferential side surface of the groove 59 and the portion separated from the groove 59 in the circumferential direction are provided with The convex curved surface 60 of the circular arc cross-sectional shape prevents the O-ring 15 from being damaged by the gentle portion. Instead of the convex curved surface 60, an inclined surface whose inner diameter gradually changes may be provided.

Even in the case of the present embodiment as described above, when the holder shaft portion 48 to which the O-ring 15 is fitted is inserted into the holder insertion hole 36b, a portion of the outer peripheral surface of the O-ring 15 can be A gap 56 is provided between (the lower part in FIG. 8 ) and the bottom surface of the groove 59 , that is, the partial cylindrical surface 57 a . Thereby, the air inside the holder insertion hole 36b can be made to pass through this clearance gap 56, and can be released to the outside.

The other configurations and effects are the same as those of the first embodiment.

In the case of implementing the present invention, the shape of the annular recess formed on the inner peripheral surface of the cage insertion hole and the shape of the bottom surface of the groove is not limited to a tapered surface or a cylindrical surface (partial cylindrical surface). other shapes. In addition, when a groove is formed on the inner peripheral surface of the holder insertion hole, the number of grooves is not limited to one, and a plurality of grooves may be formed. In addition, in the embodiment, the bearing cap was described as an example of a structure in which a cap body made of synthetic resin and a member made of a material other than synthetic resin, such as a metal ring, were combined, but in the case of implementing the present invention Next, the entire bearing cap may be made of synthetic resin. Furthermore, the configurations of the respective embodiments can be implemented by combining them appropriately.

Claims (6)

1. A bearing cap with a sensor unit, characterized in that it has: A bearing cap having a cylindrical shape with a bottom is attached to an axially inner portion of an outer ring that is rotatably supported by a hub having an encoder, closes an axially inner opening of the outer ring, and has a connection with the outer ring. A fitting cylindrical portion to be fitted and fixed, and a bottom plate portion made of synthetic resin that closes the inner diameter side of the fitting cylindrical portion, the bottom plate portion is provided with a A cage insertion hole with a bottomed hole opened in the axial direction; A sensor unit including a sensor holder having a holder shaft portion inserted into the holder insertion hole, and a sensor, which is attached to the bearing cap, and a sensor held by the holder shaft portion the top end of the ; and an elastic ring arranged in a radially compressed state between an inner peripheral surface of an axially intermediate portion of the cage insertion hole and an outer peripheral surface of an axially intermediate portion of the cage shaft portion, The retainer insertion hole has an escape portion in a range from an axially inner opening to a position adjacent to an axially inner side of an arrangement position of the elastic ring in at least a part of the inner peripheral surface in the circumferential direction, and the The inner radius of the outgassing portion is larger than the outer radius of the elastic ring fitted on the cage shaft portion before being inserted into the cage insertion hole. 2. The bearing cap with sensor unit according to claim 1, characterized in that: The outgassing portion is an annular recessed portion provided over the entire circumference of the inner peripheral surface of the cage insertion hole. 3. The bearing cap with sensor unit according to claim 2, wherein, The bottom surface of the annular recessed portion is a tapered surface inclined in a direction in which the inner diameter becomes larger as it goes inward in the axial direction. 4. The bearing cap with sensor unit according to claim 2, characterized in that, The bottom surface of the annular recessed portion is a cylindrical surface having a constant inner diameter in the axial direction. 5. The bearing cap with sensor unit according to claim 1, wherein, The outgassing portion is a groove provided on a part of the inner peripheral surface of the holder insertion hole in the circumferential direction. 6. A hub unit bearing comprising: an outer ring having an outer ring raceway on an inner peripheral surface; a hub having an inner ring raceway on an outer peripheral surface; and a hub provided on the outer ring raceway and the inner ring raceway a plurality of rolling elements between; an encoder supported on an axially inner portion of the hub coaxially with the hub; a bearing cap mounted on an axially inner portion of the outer ring; and mounted on the bearing The sensor unit of the cover, the bearing of the hub unit is characterized by, A bearing cap with a sensor unit in which the sensor unit is mounted on the bearing cap is the bearing cap with a sensor unit according to any one of claims 1 to 5 .

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