JP5002992B2 - Rolling bearing with encoder - Google Patents

Description

  The rolling bearing with an encoder according to the present invention is used to support a wheel of a motorcycle such as a motorcycle or a scooter so as to be rotatable with respect to a frame, and to determine the rotational speed of the wheel.

An anti-lock brake system (ABS) is widely used as a device for stabilizing the running state for automobiles. Such ABS has been widely used mainly in four-wheeled vehicles, but has recently begun to be used in motorcycles. As is well known, since it is necessary to determine the rotational speed of the wheel in order to control the ABS, it is necessary to incorporate a rotational speed detection device into the wheel bearing rolling bearing unit for rotatably supporting the wheel on the suspension device. It has been widely practiced. However, the structure of the rotational speed detection device for a four-wheeled vehicle cannot be directly applied to a motorcycle. There are two main reasons for this (1) and (2).
(1) The wheel support rolling bearing unit for motorcycles is considerably smaller than the wheel support rolling bearing unit for automobiles.
(2) While most of the wheel bearing rolling bearing units for four-wheeled vehicles are of the inner ring rotating type, many of the wheel supporting rolling bearing units for motorcycles are of the outer ring rotating type.

  FIG. 10 shows a structure of a part that rotatably supports the front wheel of a relatively small motorcycle, such as a scooter, as an example of the structure of the wheel support part of the motorcycle. In this structure, a pair of support plates 2 and 2 are fixed in parallel to each other at the lower ends of a pair of left and right forks 1 and 1 constituting the suspension device. The both ends of the support shaft 3 are supported and fixed between the support plates 2 and 2. Further, a pair of rolling bearings 4 and 4 are installed at two positions of the intermediate portion of the support shaft 3. Specifically, the inner rings constituting the both rolling bearings 4 and 4 are fitted onto the support shaft 3, and the axial positions of the inner rings are regulated by the inner ring spacers 5a, 5b and 5c. A cylindrical hub 6 is arranged around the support shaft 3 concentrically with the support shaft 3. And the outer ring | wheel which comprises the said both rolling bearings 4 and 4 is internally fitted and fixed to the inner peripheral surface near both ends of the said hub 6. FIG. Further, a wheel 7 is supported and fixed to the outer peripheral surface of the hub 6.

  On the other hand, a structure described in Patent Document 1 is conventionally known as a rotational speed detection device for obtaining the rotational speed of a wheel in order to incorporate ABS in a motorcycle. Although the structure described in Patent Document 1 is a rotational speed detection device for a motorcycle, it is intended to detect the rotational speed of a hub constituting a wheel bearing rolling bearing unit of an inner ring rotation type. For this purpose, an encoder having an outer peripheral surface as a detected surface is fixed at an intermediate portion of the rotating shaft that rotates together with the wheel, between the pair of rolling bearing units. Further, the detection part of the sensor supported on the non-rotating outer ring is placed in close proximity to the outer peripheral surface of the encoder. Although such a structure can be applied to a relatively large motorcycle, it cannot be applied to a structure using a wheel bearing rolling bearing unit of an outer ring rotation type, which is common in a small motorcycle.

  On the other hand, in Patent Documents 2 and 3, an encoder is attached to a part of the seal ring that closes the end opening of the rolling bearing unit, and the rotational speed of the rotation-side bearing ring constituting the rolling bearing unit can be measured. Is described. Of Patent Documents 2 and 3, Patent Document 2 describes an outer ring rotation type structure, and Patent Document 3 describes an inner ring rotation type structure. However, the wheel bearing rolling bearing units with encoders described in Patent Documents 2 and 3 are all intended to detect the rotational speed of wheels of a four-wheeled vehicle, and the rolling bearing units are relatively It is large. For this reason, for example, even when the structure described in Patent Document 2 which is an outer ring rotating type is used when detecting the rotational speed of a wheel of a motorcycle, it is difficult to ensure the width dimension of the encoder in the radial direction. Problems such as difficulty in ensuring reliability with respect to speed detection occur.

  In particular, in the case of the rolling bearing with an encoder described in Patent Document 2, since the encoder and the seal lip are arranged in series in the radial direction, the distance between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. As a result, the ratio of the width dimension of the encoder becomes smaller. In the case of a rolling bearing unit for supporting a wheel of a motorcycle, since the distance between the two peripheral surfaces is originally small, the absolute value of the width dimension of the axial side surface, which is the detected surface of the encoder, is considerably reduced when the ratio is small. Get smaller. As a result, the change in the output signal of the sensor having the detection unit opposed to the detected surface becomes small, which is disadvantageous in terms of ensuring the reliability of rotation speed detection. In short, the structures described in Patent Documents 2 and 3 cannot be used as they are to detect the rotational speed of the wheels of the motorcycle.

JP-A-5-105158 JP 2005-121669 A JP 2005-233923 A

  The present invention has been invented in order to realize a rolling bearing with an encoder capable of detecting the rotational speed of a motorcycle wheel with high reliability in view of the circumstances as described above.

The rolling bearing with an encoder of the present invention includes an outer ring, an inner ring, a plurality of rolling elements, and an encoder.
Of these, the outer ring has an outer ring raceway on the inner peripheral surface and rotates during use.
The inner ring has an inner ring raceway on the outer peripheral surface and does not rotate during use.
Each rolling element is provided between the inner ring raceway and the outer ring raceway so as to roll freely.
The encoder rotates together with the outer ring, and alternately changes the magnetic characteristics of the outer surface in the axial direction, which is the side surface opposite to the rolling element, in the circumferential direction.
In addition, the outer peripheral edge of the encoder is supported and fixed to the outer end in the axial direction of the outer ring in a state in which a sealing property between the outer ring and the outer ring is ensured. The entire circumference is in sliding contact or in close proximity.
Further, in the case of the present invention , a concave groove having a deep outer diameter side and a shallow inner diameter side is formed over the entire circumference at a portion closer to the inner diameter of the outer surface in the axial direction of the encoder.

When carrying out the present invention as described above, for example, as in the invention described in claim 3 , an encoder including a cored bar and a permanent magnet is used as the encoder. Of these, the metal core is formed of a magnetic metal plate such as a steel plate, a ferritic or martensitic stainless steel plate, etc., in a ring shape as a whole. And the cylindrical part formed in the outer periphery of the said metal core is fitted and fixed to the inner peripheral surface of the axial direction outer end part of the said outer ring by interference fitting.
The permanent magnet is formed by dispersing magnetic powders such as iron and ferrite in a polymer material such as an elastomer such as rubber or a plastomer such as a synthetic resin. The poles are arranged alternately. Such a permanent magnet is attached to the outer surface in the axial direction of the cored bar.

Alternatively, when the present invention is implemented , the encoder is configured to include an annular permanent magnet made of a sintered material, for example, as in the invention described in claim 2 . S poles and N poles are alternately arranged on the outer surface in the axial direction of the permanent magnet, and the inner peripheral edge of the permanent magnet is closely opposed to the outer peripheral surface of the inner ring over the entire circumference. In other words, the labyrinth seal is provided between the inner peripheral edge and the outer peripheral surface without bringing the inner peripheral edge of the permanent magnet into contact with the outer peripheral surface of the inner ring.

Further, when the present invention is carried out, preferably, as in the invention described in claim 4 , the inner circumference of the outer circumferential surface of the outer ring in the axial direction outer end portion is larger in inner diameter than the portion adjacent to the inner side in the axial direction. A surface-side large diameter portion is provided. Then, the outer peripheral edge portion of the encoder is fitted and fixed to the inner peripheral surface side large diameter portion.
Alternatively, as in the invention described in claim 5 , instead of omitting the inner peripheral surface side large diameter portion, or providing this inner peripheral surface side large diameter portion, the outer peripheral surface of the inner ring in the axial direction outer end portion is provided. A small-diameter portion on the outer peripheral surface side having an outer diameter smaller than that of the portion adjacent to the inside in the axial direction is provided. Then, the inner peripheral edge portion of the encoder enters the outer peripheral surface side small diameter portion, and the inner peripheral edge portion and the portion adjacent to the inner side in the axial direction are overlapped with each other in the axial direction.

According to the present invention configured as described above, it is possible to realize a rolling bearing with an encoder that can detect, for example, the rotational speed of a wheel of a motorcycle with high reliability. That is, in the case of the present invention, the outer peripheral edge of the encoder is supported and fixed to the outer end in the axial direction of the outer ring, and the inner peripheral edge of the encoder itself is slidably contacted or closely opposed to the inner ring over the entire circumference. Therefore, the width dimension of the encoder in the radial direction can be ensured. For this reason, it is possible to increase the change in the output signal of the sensor in which the detection unit is opposed to the outer surface in the axial direction, which is the detection surface of the encoder, and it is easy to ensure the reliability of rotation speed detection.
Further, in the case of the present invention, a concave groove having a deep outer diameter side and a shallow inner diameter side adheres to the outer side surface of the encoder in the axial direction and collects foreign matters moving on the outer side surface in the axial direction toward the inner diameter side. This foreign matter is prevented from reaching the inner peripheral edge of the encoder. For this reason, the outstanding effect can be acquired regarding the foreign material approach prevention into the space which installed the rolling element.
For example, when an encoder including a ring-shaped permanent magnet as shown in claims 2 and 3 is used, the magnetic flux entering and exiting the detected surface of the encoder is increased to greatly change the output signal of the sensor. it can.
In particular, if the structures described in claims 4 and 5 are employed, the width dimension of the encoder in the radial direction is set such that the inner peripheral surface of the outer ring is adjacent to the inner peripheral surface side large diameter portion and the outer peripheral surface of the inner ring. Among these, it can be made larger than the interval with the portion adjacent to the outer peripheral surface side small diameter portion. For this reason, the width dimension of the encoder can be further increased, the change in the output signal of the sensor can be increased, and the reliability of rotation speed detection can be further improved. Further, in the case of the structure described in claim 4 , in addition to the above effects, the outer diameter side end of the inner surface in the axial direction of the encoder is abutted with the stepped portion existing behind the large diameter portion on the inner peripheral surface side. Thus, the effect that the axial position of the encoder can be easily and reliably regulated can be obtained.

[ First example of reference example of the present invention ]
FIG. 1 shows a first example of a reference example related to the present invention . The rolling bearing 8 with an encoder according to this reference example includes an outer ring 9, an inner ring 10, a plurality of rolling elements 11, and an encoder 12. The inner diameter R (of the inner ring 10) of the rolling bearing with encoder 8 is, for example, about 12 to 25 mm, and the outer diameter D (of the outer ring 9) is about 35 to 50 mm. In use, for example, as shown in FIG. 10, the hub 6 is assembled between the outer peripheral surface of the support shaft 3 and the inner peripheral surface of the hub 6 so that the hub 6 can be freely rotated around the support shaft 3. To support. When the structure of this reference example is applied to the structure shown in FIG. 10, only one of the pair of rolling bearings 4 and 4 shown in FIG. And The other rolling bearing is a general rolling bearing without an encoder.

As described above, for example, the outer ring 9 constituting the rolling bearing 8 with the encoder assembled between the outer peripheral surface of the support shaft 3 and the inner peripheral surface of the hub 6 has the outer ring raceway 13 on the inner peripheral surface. Have. In the illustrated example, the outer ring raceway 13 is a deep groove type having a circular arc cross section. Such an outer ring 9 rotates together with the hub 6 while being fitted and fixed to the hub 6 at the time of use.
The inner ring 10 has an inner ring raceway 14 on the outer peripheral surface. In the illustrated example, the inner ring raceway 14 is also of a deep groove type. Such an inner ring 10 does not rotate while being fitted and fixed to the support shaft 3 during use.
Each rolling element 11 is provided between the outer ring raceway 13 and the inner ring raceway 14 so as to be freely rollable while being held by a cage 15. In the illustrated example, balls are used as the rolling elements 11.

The encoder 12 is formed by integrally connecting and fixing a metal core 16 and a permanent magnet 17 each having an annular shape. Of these, the core 16 is made of a magnetic metal plate such as a steel plate, a ferritic or martensitic stainless steel plate, and the outer peripheral edge of the annular portion 18 is axially outward (the space in which the rolling elements 11 are installed). On the opposite side, the cylindrical portion 19 is formed by being bent at right angles toward the left side of FIG. 1, and is formed into an annular shape with an L-shaped cross section.
The core metal 16 constituting the encoder 12 is not limited to the structure shown in FIG. 1, and the cylindrical portion 19 for fitting to the inner peripheral surface of the end of the outer ring 9 and the permanent magnet 17 are held. What is necessary is just a structure provided with the ring part 18. FIG. For example, as shown in FIG. 11, the metal core 16 constituting the encoder 12 is configured such that a locking portion 32 having a crank-shaped cross section is provided between the outer peripheral edge portion of the annular ring portion 18 and the cylindrical portion 19. You can also do things. When such a configuration is adopted, the cylindrical portion 19 and the inner peripheral surface of the end of the outer ring 9 are directly fitted (without the permanent magnet 17), and the locking portion 32 and the outer ring are fitted. Since the position in the radial direction of the permanent magnet 17 can be regulated between the inner peripheral surface 9 and the inner peripheral surface 9, it is possible to improve the detection accuracy related to rotation speed detection.

  On the other hand, the permanent magnet 17 is formed by dispersing magnetic powder such as iron or ferrite in a polymer material such as elastomer such as rubber or plastomer such as synthetic resin. Such a permanent magnet 17 is manufactured by injection molding, in which the polymer material containing the magnetic powder is fed into a mold cavity. At the time of injection molding, the core metal 16 is set in the cavity. deep. In addition, a primer (adhesive) is applied in advance to the surface of the core bar 16 that contacts the permanent magnet 17. Accordingly, the permanent magnet 17 and the cored bar 16 are joined and fixed simultaneously with the injection molding of the permanent magnet 17. The permanent magnet 17 is magnetized in the axial direction, and the magnetization direction is alternately varied at equal intervals in the circumferential direction. Therefore, the south pole and the north pole are alternately arranged at equal intervals on the outer surface in the axial direction of the permanent magnet 17 that is the detected surface. The number of these S poles and N poles is regulated by design depending on the performance required for the ABS, etc., but at most 50 poles on the entire circumference of the permanent magnet 17 (a total of 100 S poles and N poles). Extreme).

  The inner peripheral edge of the permanent magnet 17 protrudes radially inward from the inner peripheral edge of the cored bar 16. Therefore, the inner peripheral edge of the encoder 12 as a whole is the inner peripheral edge of the permanent magnet 17. As described above, the permanent magnet 17 is manufactured by injection molding of the polymer material. Therefore, the inner diameter of the permanent magnet 17 and the inner diameter of the encoder 12 as a whole can be finished with high accuracy. Moreover, the axial direction outer side surface of the permanent magnet 17 is an outer diameter side end portion, and is axially inner than the intermediate portion or inner diameter side portion (on the space side where the rolling elements 11 are installed, on the right side in FIG. 1). It is recessed. Therefore, the annular recess 20 exists on the outer diameter side end of the axially outer side surface of the encoder 12 over the entire circumference. Then, a gate for injection molding the permanent magnet 17 is positioned on the bottom surface of the annular recess 20, and the presence of the gate is a surface to be detected. The magnetic flux entering and exiting from the outer surface of the permanent magnet 17. Prevents negative effects on density. Further, the outer surface of the permanent magnet 17 in the axial direction is present at a position recessed inward in the axial direction from the end surfaces of the outer ring 9 and the inner ring 10. Therefore, before the rolling bearing 8 with the encoder is assembled between the hub 6 and the support shaft 3, the encoder 12 may collide with another object and be damaged in the state of the rolling bearing 8 with the encoder alone. Can be prevented.

  Furthermore, an inner peripheral surface side large-diameter portion 21 having an inner diameter larger than that of the portion adjacent to the inner side in the axial direction is formed at the axially outer end portion of the inner peripheral surface of the outer ring 9. The encoder 12 as described above is fitted inside the end portion of the outer ring 9 by fitting the cylindrical portion 19 formed on the outer peripheral edge portion of the core metal 16 into the inner peripheral surface side large-diameter portion 21 with an interference fit. It is fixed to the peripheral surface. In this state, the sealing performance between the inner peripheral surface of the end portion of the outer ring 9 and the outer peripheral edge of the encoder 12 is ensured. Further, the inner peripheral edge of the encoder 12 is closely opposed to the outer peripheral surface of the end portion of the inner ring 10 over the entire periphery, and a labyrinth seal is formed between the inner peripheral edge and the outer peripheral surface. As described above, the inner diameter of the encoder 12 can be processed with sufficiently high accuracy, and the outer diameter of the inner ring 10 is also processed with high accuracy. Therefore, the width dimension in the radial direction of the labyrinth seal can be made sufficiently small, and the sealing performance of the labyrinth seal can be made sufficiently good.

According to the rolling bearing with an encoder of the present reference example configured as described above, for example, the rotational speed of a wheel of a motorcycle can be detected with high reliability. That is, in the case of this reference example, the labyrinth seal is configured with the inner peripheral edge of the encoder 12 itself facing the outer peripheral surface of the inner ring 10 in close proximity. Therefore, unlike the structure described in Patent Document 2 described above, the encoder 12 and the seal lip are arranged in series in the radial direction, and the width dimension of the encoder 12 in the radial direction can be increased. For this reason, the change in the output signal of the sensor in which the detection unit is opposed to the outer surface in the axial direction, which is the detection surface of the encoder 12, can be increased. In other words, the hub in which the outer ring 9 is fitted and fixed by increasing the magnetic flux entering and exiting from the outer surface in the axial direction of the permanent magnet 17 constituting the encoder 12 to increase the degree to which the output signal of the sensor changes. 6. As a result, it becomes easy to ensure the reliability of detecting the rotational speed of the wheel coupled and fixed to the hub 6.

Moreover, in the case of this reference example , since the outer peripheral edge of the encoder 12 is fitted into the inner peripheral surface side large diameter portion 21 formed at the end of the outer ring 9, the outer diameter of this encoder 12 is The outer ring 9 can be larger than the inner diameter of the portion adjacent to the inner peripheral surface side large diameter portion 21. For this reason, the width of the encoder 12 can be made larger, the change in the output signal of the sensor can be made larger, and the reliability of rotation speed detection can be further improved. Further, the axial position of the encoder 12 can be easily achieved by abutting the outer diameter side end portion of the inner surface in the axial direction of the encoder 12 with the step portion 22 existing in the inner diameter surface side large diameter portion 21. And it can be regulated reliably (with high accuracy). For this reason, in addition to reliably preventing the encoder 12 from interfering with the retainer 15, the distance between the detected surface of the encoder 12 and the detection portion of the sensor is properly regulated, and from this surface, The reliability related to the rotational speed detection can be improved. If the encoder 12 is made of an elastomer, the inner peripheral edge of the encoder may be brought into sliding contact with the outer peripheral surface of the inner ring 10.

[ Second Example of Reference Example of the Present Invention ]
FIG. 2 shows a second example of a reference example relating to the present invention . In the case of this reference example , the concave grooves 23 and 24 are formed over the entire circumference on the outer surface inner diameter side portion and the inner peripheral edge of the permanent magnet 17a. Of these concave grooves 23 and 24, the concave groove 23 near the inner diameter of the outer surface is attached to the outer surface in the axial direction of the encoder 12a and collects foreign matters moving on the outer diameter surface in the axial direction. It serves to prevent foreign matter from reaching the inner periphery of the encoder 12a. The concave groove 24 on the inner peripheral edge serves to increase the number of times the labyrinth seal is squeezed between the inner peripheral edge and the outer peripheral surface of the inner ring 10 to improve the sealing performance of the labyrinth seal. Therefore, the structure of the present reference example is more effective in preventing foreign matter from entering the space in which the rolling elements 11 are installed than the structure of the first example of the reference example described above. Since the structure and operation of the other parts are the same as those of the first example of the reference example described above, a duplicate description is omitted.

[ Third example of reference example of the present invention ]
FIG. 3 shows a third example of the reference example related to the present invention . In the case of this reference example , the outer peripheral surface side small-diameter portion 25 having an outer diameter smaller than that of the portion adjacent to the inner side in the axial direction is provided on the outer peripheral surface of the inner end 10a in the axial direction. The inner peripheral edge portion of the encoder 12b is inserted into the outer peripheral surface side small diameter portion 25, and the inner peripheral edge portion and the portion adjacent to the inner side in the axial direction are overlapped with each other in the axial direction. Further, a portion closer to the inner diameter of the inner surface in the axial direction of the encoder 12b and a step portion 26 existing in the back of the outer diameter surface side small diameter portion 25 are made to face each other. In the case of this reference example, the width of the encoder 12b in the radial direction, greater than the width dimension of encoder 12,12a of the second example of the first embodiment and the above-mentioned Reference Example Reference example described above Thus, the reliability relating to the rotation speed detection can be further improved. In addition, the length of the labyrinth seal existing between the inner peripheral edge of the encoder 12b and the surface of the inner ring 10a can be increased to improve the sealing performance. Since the structure and operation of other parts are the same as those in the first example of the reference example described above, a duplicate description is omitted.

[ Fourth example of a reference example related to the present invention ]
FIG. 4 shows a fourth example of the reference example related to the present invention . In the case of this reference example , the inner diameter of the inner circumferential edge of the encoder 12c is made larger than the inner diameter of the outer half of the axial direction, and a step portion 27 is formed on the inner half of this axial direction. It is formed in a row. For this reason, a portion having a larger volume than the both side portions exists in an intermediate portion between the step portion 27 and the outer peripheral surface side small diameter portion 25 provided on the outer peripheral surface of the outer end portion of the inner ring 10a. As a result, the number of times the labyrinth seal is squeezed between the inner peripheral edge of the encoder 12c and the outer surface of the inner ring 10a can be increased, and the sealing performance of the labyrinth seal can be improved. Therefore, the structure of this reference example is superior in the effect of preventing foreign matter from entering the space where the rolling elements 11 are installed, as compared with the structure of the third example of the reference example described above. Since the structure and operation of other parts are the same as those of the third example of the reference example described above, a duplicate description is omitted.

[ Fifth Example of Reference Example Related to the Present Invention ]
FIG. 5 shows a fifth example of the reference example relating to the present invention . In the case of this reference example, the inner half in the axial direction of the inner periphery of the encoder 12d is a partially conical concave surface that is inclined in a direction in which the inner diameter increases toward the inner surface in the axial direction. Further, a portion formed on the outer peripheral surface of the outer end portion of the inner ring 10b, which is inclined in a direction in which the outer diameter becomes larger toward the center of the inner ring 10b, the stepped portion 26a existing at the rear end portion of the outer peripheral side small diameter portion 25. It has a conical convex surface. The inner half of the inner periphery of the encoder 12d is in close proximity to the stepped portion 26a. Such a structure of this reference example is less likely to slip between the axially inner half portion and the stepped portion 26a even when the axial position of the inner peripheral edge of the encoder 12d is slightly shifted (gap thickness of the labyrinth seal portion). If the length is the same, the tolerance for the displacement in the axial direction is increased). Since the structure and operation of other parts are the same as those of the third example of the reference example described above, a duplicate description is omitted.

[ Sixth Reference Example for the Present Invention ]
FIG. 6 shows a sixth example of the reference example related to the present invention . In the case of this reference example , the inner peripheral edge of the cored bar 16 and the inner peripheral surface of the cylindrical part 19 are covered with a polymer material that constitutes the permanent magnet 17b of the encoder 12e. In the case of the present reference example , the length of the labyrinth seal is increased by this configuration to improve the sealing performance. In addition, even when the metal core 16 is made of a metal plate having no corrosion resistance, the metal plate can be prevented from corroding. Since the structure and operation of the other parts are the same as in the fifth example of the reference example described above, a duplicate description is omitted.

[ Seventh example of a reference example related to the present invention ]
FIG. 7 shows a seventh example of the reference example related to the present invention . In the case of this reference example , the concave groove 28 is formed over the entire circumference in the inner half in the axial direction of the outer peripheral surface side small diameter portion 25a formed on the outer peripheral surface of the end portion of the inner ring 10c. Further, the inner peripheral edge of the encoder 12f is formed in a bifurcated shape, and a concave groove 24a is formed in the inner peripheral edge over the entire periphery. Of the inner peripheral edge portion, the outer side portion in the axial direction than the concave groove 24a is close to and opposed to the outer peripheral surface of the outer half portion in the axial direction of the outer peripheral surface side small diameter portion 25a. On the other hand, the inner side surface of the inner peripheral edge of the inner side portion in the axial direction from the concave groove 24a is made to face and oppose the stepped portion 26b existing at the inner end of the outer peripheral surface side small diameter portion 25a. According to the structure of this reference example, the number of times of labyrinth seal throttling between the inner peripheral edge of the encoder 12f and the outer surface of the inner ring 10c is increased, and the volume of the space existing between the throttling is increased. Thus, the sealing performance of the labyrinth seal can be improved. Since the structure and operation of the other parts are the same as in the fifth example of the reference example described above, a duplicate description is omitted.

[ One Example of Embodiment of the Present Invention ]
FIG. 8 shows an example of an embodiment of the present invention corresponding to claims 1, 3 , 4 and 5 . In the case of this example, a concave groove 23a having a deep outer diameter side and a shallow inner diameter side is formed over the entire circumference at a portion closer to the inner diameter of the outer surface in the axial direction of the encoder 12g. The concave groove 23a collects foreign matter that adheres to the outer surface in the axial direction of the encoder 12g and moves to the inner diameter side of the outer surface in the axial direction, and prevents the foreign matter from reaching the inner peripheral edge of the encoder 12g. Has a role to play. Therefore, the structure of this example is superior in the effect of preventing foreign matter from entering the space where the rolling elements 11 are installed, as compared with the structure of the seventh example of the reference example described above. Since the structure and operation of the other parts are the same as in the seventh example of the reference example described above, a duplicate description is omitted.

  When carrying out the present invention, it is preferable that the detected surface of the encoder (the outer surface in the axial direction) and the detection portion of the sensor are directly close to each other without interposing other members. This is because it is easy to improve the reliability of rotation speed detection by increasing the change in the magnetic characteristics at the detection unit of the sensor to increase the change in the output signal of the sensor. However, in order to protect the encoder, for example, as shown in FIG. 9, the surface to be detected of the encoder 12 can be covered with a coating film 29 made of a nonmagnetic material. Alternatively, instead of omitting the coating film 29 or providing the coating film 29, the detected surface can be covered with a cover 30 made of a nonmagnetic material supported and fixed to the inner ring 10. When such a coating film 29 or cover 30 is provided, it is inevitable that the distance between the detected surface and the detection portion of the sensor becomes large. For this reason, in order to ensure a change in the output signal of the sensor, it is necessary to increase the amount of magnetic flux entering and exiting from the detection surface of the encoder 12. In order to increase the amount of the magnetic flux, it is conceivable that the encoder 12 is a plastic magnet in which magnetic powder is hardened with a thermoplastic synthetic resin. In the case of a plastic magnet, the amount of magnetic powder can be increased compared to the case of a rubber magnet, so that the amount of magnetic flux can be easily increased. The seal ring 31 provided on the side opposite to the encoder 12 is a general seal ring having no encoder.

  In addition, permanent magnets used as encoders are sintered by mixing magnetic powders such as ferrite and rare earth and nonmagnetic metal powders such as austenitic stainless steel and tin instead of rubber magnets and plastic magnets. A magnet can also be used. The shape of such a sintered magnet encoder is the same as the shape of any of the encoders shown in FIGS. 1 to 8 (a shape in which a cored bar and a permanent magnet are combined). Such an encoder made of a sintered magnet is fitted and fixed to the end of the outer ring. An encoder made of a sintered magnet has low toughness, but only a compressive stress is applied when the inner fitting is fixed, and a tensile stress that leads to a crack is not applied. Therefore, the required strength can be secured even with a single sintered magnet. Such an encoder made of a sintered magnet can be used either in the form shown in FIGS. 1 to 8 or in the form shown in FIG. That is, since the sintered magnet is high in hardness, it is not easily damaged by foreign matter, and even if it is carried out in the mode shown in FIGS. On the other hand, since it is easy to increase the amount of magnetic flux entering and exiting from the detected surface, the amount of magnetic flux reaching the detection portion of the sensor even if the embodiment shown in FIG. 9 is implemented to further enhance the protection of the detected surface. Easy to secure.

The fragmentary sectional view which shows the 1st example of the reference example regarding this invention . The fragmentary sectional view which shows the 2nd example. The fragmentary sectional view which shows the 3rd example. The fragmentary sectional view which shows the 4th example. The fragmentary sectional view which shows the 5th example. The fragmentary sectional view which shows the 6th example. The fragmentary sectional view showing the 7th example. The fragmentary sectional view which shows one example of embodiment of this invention . The fragmentary sectional view which shows the 8th example of the reference example regarding this invention . Sectional drawing which shows an example of the rotation support part of the wheel of a motorcycle. The figure equivalent to the A section of FIG. 1 which shows another example of the encoder used as the object of this invention.

DESCRIPTION OF SYMBOLS 1 Hawk 2 Support plate 3 Support shaft 4 Rolling bearing 5a, 5b, 5c Inner ring spacer 6 Hub 7 Wheel 8 Rolling bearing with an encoder 9 Outer ring 10, 10a, 10b, 10c Inner ring 11 Rolling element 12, 12a-12g Encoder 13 Outer ring track 14 Inner ring raceway 15 Cage 16 Core metal 17, 17a, 17b Permanent magnet 18 Circular ring part 19 Cylindrical part 20 Annular recess 21 Inner peripheral surface side large diameter part 22 Step part 23, 23a Concave groove 24, 24a Concave groove 25, 25a Outer peripheral surface side small diameter portion 26, 26a, 26b Step portion 27 Step portion 28 Concave groove 29 Coating film 30 Cover 31 Seal ring 32 Locking portion

Claims (5)

  An outer ring that has an outer ring raceway on the inner peripheral surface and that rotates when used, an inner ring that has an inner ring raceway on the outer peripheral surface and does not rotate even when used, and is provided between the inner ring raceway and the outer ring raceway so as to be rotatable A plurality of rolling elements and an encoder that rotates together with the outer ring and has an axially outer surface whose magnetic characteristics are alternately changed with respect to the circumferential direction, and an outer peripheral edge portion of the encoder is an outer end portion in the axial direction of the outer ring. In addition, the inner periphery of the encoder itself is slidably in contact with or close to the inner ring with respect to the inner ring in a state in which a sealing property with the outer ring is ensured. A rolling bearing with an encoder in which a concave groove having a deep outer diameter side and a shallow inner diameter side is formed over the entire circumference in a portion closer to the inner diameter of the outer side surface in the direction. The encoder is made of a sintered material and includes a ring-shaped permanent magnet. S poles and N poles are alternately arranged on the outer surface in the axial direction of the permanent magnet. The rolling bearing with an encoder according to claim 1 , wherein the inner peripheral edge is closely opposed to the outer peripheral surface of the inner ring over the entire periphery. The encoder includes a cored bar made of a magnetic metal plate in an annular shape, and a permanent magnet formed by dispersing magnetic powder in a polymer material attached to the axially outer surface of the cored bar. A cylindrical portion formed on the outer peripheral edge of the core metal is fitted and fixed to the inner peripheral surface of the outer end in the axial direction of the outer ring by an interference fit, and the S pole and the N pole are fixed on the outer side in the axial direction of the permanent magnet. The rolling bearings with an encoder according to claim 1 , which are arranged alternately. An inner peripheral surface side large-diameter portion whose inner diameter is larger than a portion adjacent to the inner side in the axial direction is provided on the inner peripheral surface of the outer end portion in the axial direction of the outer ring. The rolling bearing with an encoder according to any one of claims 1 to 3 , which is fitted and fixed to a diameter portion. An outer peripheral surface side small diameter portion having an outer diameter smaller than a portion adjacent to the inner side in the axial direction is provided on the outer peripheral surface of the inner end in the axial direction of the inner ring, and the inner peripheral edge portion of the encoder is connected to the outer peripheral surface side small diameter portion. The rolling bearing with an encoder according to any one of claims 1 to 4 , wherein the inner peripheral edge portion and the portion adjacent to the inner side in the axial direction overlap with each other in the axial direction.

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