JP3653885B2 - Magnetizer for encoder for rotational speed detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a magnetizing device used for making an encoder incorporated in a rolling bearing unit with a rotational speed detecting device for rotatably supporting a vehicle wheel on a suspension device and detecting the rotational speed of the wheel. .
[0002]
[Prior art]
Rotational speed detection for detecting the rotational speed of an automobile wheel to support the suspension system and to control an anti-lock brake system (ABS) or traction control system (TCS). Various types of rolling bearing units with devices have been known in the past. Each of the rotational speed detection devices incorporated in such a rolling bearing unit with a rotational speed detection device includes a tone wheel that rotates together with the wheel, and a sensor that outputs an output signal that changes at a frequency proportional to the rotational speed of the tone wheel. Prepare. For example, JIII Journal of Technical Disclosure No. 94-16051 describes a rolling bearing unit with a rotational speed detection device as shown in FIG.
[0003]
The outer end of the hub 1 constituting the inner member (outside means the side outside the width direction of the vehicle when assembled to the vehicle, left in FIGS. 3 and 4) A flange portion 2 is formed, and an inner ring raceway 3a and a step portion 4 are formed on the outer peripheral surface of the intermediate portion. Further, an inner ring raceway 3b is formed on the outer circumferential surface of the hub 1, and the inner ring 5 that constitutes an inner member together with the hub 1 is outside with the outer end surface abutted against the stepped portion 4. Fits and supports. The inner ring raceway 3a is not formed directly on the outer peripheral surface of the hub 1, but is formed on an inner ring (not shown) separate from the hub 1, and the inner ring and the inner ring 5 are connected to the hub 1. In some cases, it is fixed.
[0004]
Further, a male screw portion 6 is formed at a portion near the inner end of the hub 1. The inner ring 5 is fixed to a predetermined portion of the outer peripheral surface of the hub 1 by a nut 7 screwed into the male screw portion 6 and further tightened to constitute an inner member. A mounting portion 9 for fixing the outer member 8 to the suspension device is provided on the outer peripheral surface of the intermediate portion of the outer member 8 disposed around the hub 1. Further, outer ring raceways 10a and 10b are formed on the inner peripheral surface of the outer member 8 so as to face the inner ring raceways 3a and 3b, respectively. A plurality of rolling elements 11, 11 are provided between the inner ring raceways 3a, 3b and the outer ring raceways 10a, 10b, respectively, so that the inner member can freely rotate inside the outer member 8. . In the illustrated example, balls are used as the rolling elements 11, 11, but in the case of a rolling bearing unit for automobiles that is heavy in weight, tapered rollers may be used as the rolling elements. Further, a seal ring 12 is attached between the outer peripheral surface of the outer end portion of the outer member 8 and the outer peripheral surface of the hub 1 so that the inner peripheral surface of the outer member 8 and the outer peripheral surface of the hub 1 are interposed. And the outer end opening of the space provided with the plurality of rolling elements 11, 11 is closed.
[0005]
An inner end portion of the inner ring 5 (inside means a side closer to the center in the width direction of the vehicle when assembled to the vehicle, and on the right side in FIGS. 3 and 4) The base end portion 13 (the left end portion in FIG. 4) is fitted and fixed. The encoder 13 is formed in an annular shape (short cylindrical shape) as a whole by a ferromagnetic metal plate such as a steel plate. The encoder 13 is formed by connecting a small-diameter portion 14 and a large-diameter portion 15 formed concentrically with each other through a step portion 16. Such an encoder 13 is supported by the inner ring 5 in a state where the large-diameter portion 15 is fitted on the outer peripheral surface of the end portion of the inner ring 5 and the stepped portion 16 is in contact with the end edge portion of the inner ring 5. It is fixed. Therefore, the small diameter portion 14 is supported concentrically with the inner ring 5. The small-diameter portion 14 is formed with a plurality of through-holes 17 which are rotation side thinning portions at equal intervals in the circumferential direction, and the magnetic characteristics in the circumferential direction are changed alternately and at equal intervals. ing. Each through-hole 17 has the same shape and is a rectangle that is long in the axial direction (left-right direction in FIG. 4).
[0006]
The inner end opening of the outer member 8 is closed by a cover 18 made of a bottomed cylinder by drawing a metal plate such as a stainless steel plate or an aluminum alloy plate. An annular synthetic resin 21 in which an annular sensor 20 is embedded is held and fixed on the inner peripheral side of the cylindrical portion 19 constituting the cover 18. This sensor 20 includes a permanent magnet 22, a stator 23 made of a ferromagnetic material such as a steel plate, and a coil 24. By embedding these members 22, 23, 24 in the synthetic resin 21, The whole is configured in an annular shape.
[0007]
The permanent magnet 22 among the constituent members of the sensor 20 is formed in an annular shape (annular shape) as a whole, and is magnetized in the diametrical direction. Then, the inner peripheral surface of the permanent magnet 22 is opposed to the outer peripheral surface of the portion where the through hole 17 is not formed at the proximal end portion of the small diameter portion 14 constituting the encoder 13 through a minute gap 25. ing. Further, the stator 23 has a substantially J-shaped cross section and is formed in an annular shape as a whole. The end inner peripheral surface of the outer diameter side cylindrical portion 26 constituting the stator 23 and the outer peripheral surface of the permanent magnet 22 are brought close to or in contact with each other. Further, a minute gap 25 is also formed on the inner peripheral surface of the cylindrical portion 27 on the inner diameter side constituting the stator 23 in a portion of the small diameter portion 14 constituting the encoder 13 and the plurality of through holes 17 are formed. Through. Further, the inner diameter side cylindrical portion 27 is provided with a plurality of cutouts 28 that are fixed side thinning portions at the same pitch (center angle) as the through holes 17 along the circumferential direction of the inner diameter side cylindrical portion 27. Pitch). Therefore, the inner diameter side cylindrical portion 27 is formed in a comb shape.
[0008]
Further, the coil 24 is formed in an annular shape by winding a conducting wire around a bobbin 29 made of a non-magnetic material, and is arranged on the inner peripheral side portion of the outer diameter side cylindrical portion 26 constituting the stator 23. . The electromotive force induced in the coil 24 is taken out from the connector 30 protruding from the outer surface of the cover 18.
[0009]
When the encoder 13 rotates together with the inner ring 5 constituting the inner member at the time of use of the rolling bearing unit with the rotational speed detector configured as described above, the magnetic flux density in the stator 23 facing the encoder 13 changes, and the above The voltage induced in the coil 24 changes at a frequency proportional to the rotational speed of the hub 1. The principle that the voltage induced in the coil 24 changes in response to the change in the density of the magnetic flux flowing through the stator 23 is the same as that of a conventionally known rotation speed detection sensor. The reason why the density of the magnetic flux flowing through the stator 23 changes according to the rotation of the encoder 13 is as follows.
[0010]
Since the plurality of through holes 17 provided in the encoder 13 and the notches 28 provided in the stator 23 have the same pitch, there is a moment when the encoder 13 faces the entire circumference simultaneously with the rotation of the encoder 13. Then, at the moment when each through hole 17 and each notch 28 face each other, the column portion, which is a ferromagnetic material existing between the adjacent through holes 17, and between the adjacent notches 28 also. Tongue pieces, which are ferromagnetic bodies, are opposed to each other through the minute gap 25. In this way, in a state where the column portions and the tongue pieces, each of which is a ferromagnetic material, face each other, a high-density magnetic flux flows between the encoder 13 and the stator 23.
[0011]
On the other hand, if the phase of the through hole 17 and the notch 28 is shifted by half, the density of the magnetic flux flowing between the encoder 13 and the stator 23 becomes low. That is, in this state, the through hole 17 provided in the encoder 13 faces the tongue piece, and at the same time, the notch 28 provided in the stator 23 faces the column portion. Thus, in a state where the column portion is opposed to the notch 28 and the tongue piece is opposed to the through-hole 17, a relatively large gap exists between the encoder 13 and the stator 23 over the entire circumference. And in this state, the density of the magnetic flux which flows between these both members 13 and 23 becomes low. As a result, the voltage induced in the coil 24 changes in proportion to the rotational speed of the hub. By acting as described above, the sensor 20 changes the output voltage induced in the coil 24 at a frequency proportional to the rotational speed of the inner member.
[0012]
In the case of a rolling bearing unit with a rotational speed detection device configured and acting as described above, the magnetic flux emitted from the end face of the permanent magnet 22 constituting the sensor 20 is always the same in the stator 23 constituting the sensor 20. Flow in the direction. Only the magnitude of the magnetic flux density changes with the rotation of the encoder 13, and a voltage is induced in the coil 24 in response to the change in the magnetic flux density. For this reason, it is difficult to increase the amount of voltage change (difference between the maximum value and the minimum value). In particular, when the speed at which the magnetic flux density changes during low-speed running is slow, the absolute value and change of the induced voltage are changed. The amount becomes smaller.
[0013]
In view of such circumstances, conventionally, a permanent magnet is provided on the encoder side, and a part of the permanent magnet is provided with S and N poles alternately on the surface facing the sensor, over the circumferential direction, and Structures that are arranged at equal intervals have been proposed. If an encoder incorporating such a permanent magnet is used, a reverse magnetic flux (alternating magnetic flux) can flow alternately in the stator constituting the sensor. Therefore, it is possible to cause a reverse voltage to be alternately induced in the coil attached to the stator as the encoder rotates, and the output of the sensor can be increased.
[0014]
In order to increase the output of the sensor, it is effective to increase the diameter of the detection surface of the encoder facing the sensor. For this purpose, it is conceivable that, contrary to the structure shown in FIG. 4, the encoder is arranged on the outside in the diameter direction of the sensor and the diameter of the inner peripheral surface of the encoder, which is the detection surface, is increased. Increasing the diameter of the encoder is also effective in increasing the number of poles arranged in the encoder and improving detection accuracy.
[0015]
FIG. 5 shows an encoder 31 that satisfies such a requirement and a magnetizing device 33 for magnetizing the permanent magnet 32 that constitutes the encoder 31. The encoder 31 includes an annular support ring 34 made of a metal plate and a permanent magnet 32 supported and fixed over the entire circumference of the support ring 34. The support ring 34 includes a small-diameter portion 35 for fitting and fixing to a rotating wheel such as the inner ring 5 (FIG. 4), a large-diameter portion 36 concentric with the small-diameter portion 35, and an end of the large-diameter portion 36. An annular step 37 is provided to connect the edge and the edge of the small-diameter portion 35. The permanent magnet 32 is formed in a cylindrical shape as a whole and is attached to the inner peripheral surface of the large-diameter portion 36 over the entire circumference. Then, on the inner peripheral surface of the permanent magnet 32, S poles and N poles are alternately arranged at equal intervals over the circumferential direction.
[0016]
On the other hand, a magnetizing device 33 for magnetizing the permanent magnet 32 to constitute the encoder 31 includes a plurality of magnetized terminals 39, 39 at the tip of the ferromagnetic yoke 38 (left end in FIG. 5). The permanent magnets 32 are arranged in a cylindrical shape at equal intervals in the circumferential direction at the same pitch as the pitch of the adjacent S pole and N pole. The magnetized terminals 39, 39 are diametrically extended from the outer peripheral surface of the tip of the yoke 38 by a number equal to the sum of the number of S poles and the number of N poles arranged on the inner peripheral surface of the permanent magnet 32. It is provided in a state of projecting outward, and each outer peripheral end face is long in the axial direction of the permanent magnet 32 (left and right direction in FIG. 5). Coils 40 and 40 are wound around these magnetized terminals 39 and 39, respectively. Each of the coils 40, 40 has a diametrical direction of a magnetic body (permanent magnet material, high holding force material) to be the permanent magnet 32 with the outer peripheral end faces of the magnetized terminals 39, 39 facing each other when energized. Magnetize by hitting.
[0017]
The portion surrounding the magnetized terminals 39, 39 at the tip of the yoke 38 is covered with a synthetic resin 41, and the coils 40, 40 are embedded in the synthetic resin 41. A positioning plate 42 made of a metal plate or the like is fixed to the front end surface of the synthetic resin 41. When the permanent magnet 32 is magnetized and S poles and N poles are alternately arranged on the inner peripheral surface of the permanent magnet 32, the positioning plate 42 is abutted against the step portion 37 of the support ring 34. In this state, the respective magnetized terminals 39, 39 are opposed to the inner peripheral surface of the magnetic body (permanent magnet material, high coercive force material) constituting the permanent magnet 32 over the entire length of the magnetic body. Therefore, in this state, the coils 40, 40 are energized to magnetize the magnetic body, and the permanent magnet 32 is formed with S poles and N poles alternately and equally spaced on the inner peripheral surface.
[0018]
[Problems to be solved by the invention]
When the permanent magnet 32 of the encoder 31 having the structure shown in FIG. 5 is magnetized by the conventional magnetizing device 33 as shown in FIG. 5, the edge of the permanent magnet 32 and the support ring 34 are formed. The distance L ₃₂ from the side surface of the stepped portion 37 cannot be made sufficiently small. That is, the front end surface of the yoke 38 and the stepped portion are arranged with the outer peripheral end surfaces of the magnetized terminals 39 and 39 constituting the magnetizing device 33 and the inner peripheral surface of the magnetic material constituting the permanent magnet 32 facing each other. Between them, there is a synthetic resin 41 and a positioning plate 42 in which a part of the coil 40 is embedded. The distance L ₃₂ is inevitably increased by this amount.
As the distance L ₃₂ increases, the axial dimension of the encoder 31 increases correspondingly, and it becomes difficult to reduce the size and weight of the rolling bearing unit with a rotation speed detection device incorporating the encoder 31.
The magnetizing device for the encoder for the rotational speed detecting device of the present invention and the rolling bearing unit with the rotational speed detecting device incorporating the encoder have been invented in view of such circumstances.
[0019]
[Means for Solving the Problems]
As in the conventional structure shown in FIG. 5, the magnetizing device for the encoder for the rotational speed detecting device of the present invention is made of a metal plate and supported on an annular support ring and the entire circumference of the support ring. The encoder is composed of a fixed permanent magnet. The support ring includes a small-diameter portion for fitting and fixing to the rotating wheel, a large-diameter portion concentric with the small-diameter portion, and an edge of the large-diameter portion. A ring-shaped stepped portion that is continuous with the edge of the small diameter portion, and the permanent magnet is attached to the inner peripheral surface of the large diameter portion over the entire circumference, and is circumferentially connected to the inner peripheral surface. Therefore, in order to magnetize the permanent magnet of the encoder for a rotational speed detection device having a cylindrical shape in which the S pole and the N pole are alternately arranged at equal intervals, the adjacent S pole and N pole of this permanent magnet Are arranged in a cylindrical shape at equal intervals in the circumferential direction at the same pitch as the pitch of each of the outer peripheral end surfaces in the axial direction of the permanent magnet. In addition, a number of ferromagnetic magnetized terminals equal to the sum of the number of S poles and the number of N poles arranged on the inner peripheral surface of the permanent magnet are wound around these magnetized terminals. And a coil that magnetizes a magnetic body (permanent magnet material, high coercive force material) that should become the permanent magnet, with the outer peripheral end faces of each of the magnetized terminals facing each other when energized.
In particular, in the magnetizing device for the encoder for the rotational speed detecting device according to the present invention, each of the magnetized terminals is more inward than the outer peripheral end facing the inner peripheral surface of the magnetic body to be the permanent magnet. The width of the peripheral portion is narrow, and the coil is wound around the inner peripheral portion.
[0021]
[Action]
According to the magnetizing device for an encoder for a rotational speed detecting device of the present invention configured as described above, the axial dimension of the encoder can be reduced, and the rolling bearing unit with the rotational speed detecting device can be reduced in size and weight. .
[0022]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an example of an embodiment of the present invention. The magnetizing device of the encoder for the rotational speed detection device of this example is characterized in that the size of the rolling bearing unit with the rotational speed detection device is reduced by shortening the axial dimension of the encoders 31a and 31b incorporating the permanent magnet 32. It is to reduce weight. Since the structure and operation of the rolling bearing unit portion are the same as those of the conventional structure shown in FIG. 4 described above, the illustration and description relating to the same parts as those of the conventional structure are omitted or simplified. Hereinafter, encoders 31a and 31b, which are characteristic parts of the present example , a magnetizing device 33a for magnetizing the permanent magnets 32 constituting the encoders 31a and 31b, and a combination of the encoders 31a and 31b, a rotational speed detecting device. A description will be given centering on the sensor 20a constituting the.
[0023]
The encoders 31a and 31b are made of a metal plate and annular support rings 34 and 34a, and a permanent magnet 32 supported and fixed over the entire circumference of the support rings 34 and 34a. Of these, the support rings 34 and 34a include a small-diameter portion 35 and 35a for fitting and fixing to a rotating wheel such as the inner ring 5 (FIG. 3), a large-diameter portion 36 concentric with the small-diameter portions 35 and 35a, An annular stepped portion 37 is provided to allow the end of the large-diameter portion 36 and the end of the small-diameter portions 35, 35a to continue. The permanent magnet 32 is a so-called rubber magnet in which a permanent magnet material powder (high holding power material powder) such as ferrite is contained in rubber, and the whole is formed in a cylindrical shape. Such a permanent magnet 32 is attached to the inner peripheral surface of the large-diameter portion 36 over the entire circumference by baking, bonding or the like. Then, on the inner peripheral surface of the permanent magnet 32, S poles and N poles are alternately arranged at equal intervals along the circumferential direction. In addition, an inward flange-shaped flange portion 43 is formed by bending the metal plate at the intermediate portion of the inner peripheral surface of the small diameter portion 35a constituting the encoder 31b shown in FIG. The flange 43 abuts against the inner end surface of the inner ring 5 in a state where the small diameter portion 35 a is fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 5. The encoder 31b is positioned in the axial direction, and the large diameter portion 36 and the inner ring 5 are concentric.
[0024]
On the other hand, a magnetizing device 33a for magnetizing the permanent magnet 32 to constitute the encoders 31a and 31b is shown in FIGS. 1 and 2 at the tip (left end in FIG. 1) of a yoke 38a made of a ferromagnetic material. A plurality of such magnetized terminals 39a, 39a are arranged in a cylindrical shape at equal intervals in the circumferential direction at the same pitch as the pitch between the adjacent S pole and N pole of the permanent magnet 32. Each of the magnetized terminals 39a, 39a is diametrically extended from the outer peripheral surface of the tip of the yoke 38a by a number equal to the sum of the number of S poles and the number of N poles arranged on the inner peripheral surface of the permanent magnet 32. It is provided in a state of projecting outward, and each outer peripheral end face is long in the axial direction of the permanent magnet 32 (left-right direction in FIGS. 1 to 3).
[0025]
Coils 40 and 40 are wound around these magnetized terminals 39a and 39a, respectively. Each of the coils 40, 40 has a diametrical direction in which a magnetic body (permanent magnet material, high coercive force material) to be the permanent magnet 32 facing the outer peripheral end face of each of the magnetized terminals 39 a, 39 a is energized. Magnetize by hitting. In particular, the magnetized terminals 39a and 39a constituting the magnetizing device 33a of this example have a width of the inner peripheral side portion as compared with the outer peripheral side end facing the inner peripheral surface of the magnetic body constituting the permanent magnet 32. It is narrow. The coils 40 and 40 are wound around an inner peripheral side portion having a narrow width. Therefore, the end portions of the coils 40 and 40 do not protrude from the front end surface (left end surface in FIG. 1) of the magnetized terminals 39a and 39a to the front end side (left side in FIG. 1).
[0026]
The portion surrounding the magnetized terminals 39a, 39a at the tip of the yoke 38a and the portion extending from the intermediate portion to the base end are covered with a synthetic resin 41a, and the coils 40, 40 are covered in the synthetic resin 41a. The coils 40 and 40 are insulated from each other. A positioning plate 42a made of a metal plate or the like is fixed at the center of the front end surface of the synthetic resin 41a. That is, a circular recess 44 is formed in a part of the synthetic resin 41a corresponding to the tip surface of the magnetizing device 33a. The positioning plate 42a is fitted in the recess 44, and the positioning plate 42a is fixed to the yoke 38a with screws 45 and 45. The inner end surfaces of the synthetic resin 41a and the positioning plate 42a are located on the same plane. The outer diameter of the positioning plate 42a is larger than the inner diameter of the stepped portion 37 of the support rings 34, 34a.
[0027]
The permanent magnet 32 is magnetized in the diameter direction by using the magnetizing device 33a configured as described above, and the S pole and the N pole are circumferentially arranged on the inner peripheral surface of the permanent magnet 32. When alternately arranged, as shown in FIG. 1, the portion near the outer periphery of the inner end face of the positioning plate 42a abuts against the stepped portion 37 of the support rings 34, 34a. In this state, as shown in FIG. 1, the magnetized terminals 39a, 39a are arranged on the inner peripheral surface of the magnetic body (permanent magnet material, high holding force material) constituting the permanent magnet 32. Opposite across the entire length. Therefore, in this state, the coils 40a and 40a are energized to magnetize the magnetic body, and S poles and N poles are arranged alternately and at equal intervals in the circumferential direction on the inner peripheral surface. The permanent magnet 32 is used.
[0028]
In the case of the magnetizing device 33a of this example , as the shape of each of the magnetized terminals 39a and 39a is devised, the tip surface of each of the magnetized terminals 39a and 39a is made near the tip surface of the magnetized device 33a. Can be located in the part. Therefore, when magnetizing the permanent magnet 32 of the encoder 31a, 31b having the structure shown in FIGS. 1 and 3 by the magnetizing device 33a of this example , the edge of the permanent magnet 32 and the support ring 34, The distance L ₃₂ ′ from the side surface of the stepped portion 37 constituting 34a can be made sufficiently small. That is, in the state where the outer peripheral end faces of the respective magnetized terminals 39a, 39a constituting the magnetizing device 33a and the inner peripheral face of the magnetic body constituting the permanent magnet 32 are opposed to each other, the respective magnetized terminals 39a, 39a are arranged. Between the outer peripheral side end tip surface and the stepped portion 37, there is only a portion having a small thickness at the outer peripheral edge portion of the synthetic resin 41 in which a part of the coil 40 is embedded. Therefore, the distance L ₃₂ ′ is set to a dimension of 7 mm or less, which is impossible with the above-described conventional magnetizing apparatus 33 (FIG. 5), and the axial dimensions of the encoders 31a and 31b are reduced accordingly. It is possible to reduce the size and weight of the rolling bearing unit with a rotational speed detection device incorporating these encoders 31a and 31b.
[0029]
Next, although not directly related to the gist of the present invention, the structure and operation of the sensor 20a constituting the rotational speed detection device in combination with the encoders 31a and 31b as described above will be described with reference to FIG. Briefly described. This sensor 20a is formed in an annular shape as a whole, and a detection portion provided on the outer peripheral surface is opposed to the inner peripheral surface of the permanent magnet 32 constituting the encoder 31b via a minute gap 25a. Such a sensor 20a includes first and second stators 46 and 47 and a coil 24a each formed in an annular shape.
[0030]
Among these, the first and second comb-like ends are formed on the outer peripheral edge portions of the first and second stators 46 and 47 by forming notches and protruding pieces alternately and at equal intervals, respectively. Edges 48 and 49 are formed. The pitches (center angle pitches) of the notches 50 and 50 and the projecting pieces 51 and 51 constituting the comb-shaped end edges 48 and 49 are the S pole and the N pole disposed on the inner peripheral surface of the permanent magnet 32. It is made equal to the pitch of the poles (the S pole and the N pole are combined into one pitch). Further, the phase of the first comb-like edge 48 formed on the outer peripheral edge of the first stator 46 and the second comb-like edge formed on the outer peripheral edge of the second stator 47 The phase of the portion 49 is shifted by half the pitch of the notch 50 and the protruding piece 51. Therefore, at the moment when all the projecting pieces 51 constituting the first comb-shaped end edge 48 face the south pole disposed on the inner peripheral surface of the permanent magnet 32, the second comb-shaped All the projecting pieces 51 constituting the end edge portion 49 face the N pole. Further, from this moment, at the moment when the encoder 31b is rotated by half the pitch of the notches 50 and the protruding pieces 51, all the protruding pieces 51 constituting the first comb-toothed edge 48 are All the projecting pieces 51 constituting the second comb-like end edge portion 49 face the south pole, facing the north pole disposed on the inner peripheral surface of the permanent magnet 32.
[0031]
The inner peripheral edges of the first and second stators 46 and 47 are formed at the inner peripheral edge of the second stator 47 in the first cylindrical part 52 formed at the inner peripheral edge of the first stator 46. The outer end of the second cylindrical portion 53 is externally fitted with an interference fit, thereby providing magnetic conduction. Accordingly, an alternating magnetic flux flows in the first and second stators 46 and 47 as the encoder 31b rotates. The coil 24a is configured by winding a conducting wire around a bobbin 29a whose outer peripheral side is open. An uneven engagement portion is provided between the bobbin 29a and the first and second stators 46 and 47, and the phase between the first and second stators 46 and 47 is provided via the bobbin 29a. Are regulated in the state described above. An AC voltage is induced in the coil 24a formed by winding a conducting wire around the bobbin 29a in correspondence with the alternating magnetic flux.
[0032]
The sensor 20a including the first and second stators 46 and 47 and the coil 24a as described above is embedded in a synthetic resin that forms a lid 54 that closes the inner end opening of the outer member 8. A part of the lid 54 supports a sleeve 55 that is formed of a metal plate and has an L-shaped cross section and is formed in an annular shape as a whole. When the inner end opening of the outer member 8 is closed, the sleeve 55 is fitted and fixed to the inner end opening of the outer member 8. In this state, the sensor 20a is opposed to the inner peripheral surface of the permanent magnet 32 constituting the encoder 31b over the entire circumference via the minute gap 25a. A connector 30a is formed integrally with the lid body 54 on a part of the inner surface of the lid body 54 so that an AC voltage induced in the coil 24a can be taken out. This AC voltage is sent to the controller as a signal representing the rotational speed of the hub 1 and used for controlling the ABS and TCS.
[0033]
【The invention's effect】
Since the present invention is configured and operates as described above, the overall length of the rolling bearing unit with a rotational speed detecting device can be shortened, and the rolling bearing unit with the rotational speed detecting device can be made compact and lightweight. As a result, installation in a limited space is possible, and the degree of freedom in automobile design can be increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a tone wheel and a magnetizing device, showing an example of an embodiment of the present invention.
FIG. 2 is a partial perspective view of a front end portion of a magnetizing device, showing an arrangement state of magnetized terminals.
FIG. 3 is a partially enlarged cross-sectional view of a rolling bearing unit with a rotational speed detecting device incorporating a tone wheel magnetized by the magnetizing device.
FIG. 4 is a cross-sectional view showing an example of a conventional structure.
FIG. 5 is a cross-sectional view showing a conventional encoder and magnetizing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hub 2 Flange part 3 Inner ring track 4 Step part 5 Inner ring 6 Male thread part 7 Nut 8 Outer member 9 Mounting part 10 Outer ring raceway 11 Rolling element 12 Seal ring 13 Encoder 14 Small diameter part 15 Large diameter part 16 Step part 17 Through hole 18 Cover DESCRIPTION OF SYMBOLS 19 Cylindrical part 20, 20a Sensor 21 Synthetic resin 22 Permanent magnet 23 Stator 24, 24a Coil 25, 25a Minute clearance 26 Outer diameter side cylindrical part 27 Inner diameter side cylindrical part 28 Notch 29, 29a Bobbin 30, 30a Connectors 31, 31a, 31b Encoder 32 Permanent magnet 33, 33a Magnetizing device 34, 34a Support ring 35 Small diameter portion 36 Large diameter portion 37 Step portion 38, 38a Yoke 39, 39a Magnetized terminal 40 Coil 41, 41a Synthetic resin 42, 42a Positioning plate 43 位置 決 めPart 44 recess 45 screw 46 first stator 47 second stator 48 first comb Jotan'en portion 49 second comb-shaped end edge portions 50 notched 51 projecting piece 52 first cylindrical portion 53 second cylindrical portion 54 the lid 55 Sleeve

Claims (1)

  An encoder made of a metal plate and made up of an annular support ring and a permanent magnet supported and fixed over the entire circumference of the support ring. The support ring has a small diameter for fitting and fixing to the rotating wheel. A large-diameter portion concentric with the small-diameter portion, and an annular stepped portion that continues the end of the large-diameter portion and the end of the small-diameter portion, and the permanent magnet includes the large-diameter portion For a rotational speed detection device having a cylindrical shape, which is attached to the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface. In order to magnetize the permanent magnet of the encoder, the permanent magnets are arranged in a cylindrical shape at equal intervals in the circumferential direction at the same pitch as the pitch of the adjacent S poles and N poles of the permanent magnets, and the respective outer peripheral end faces are the permanent magnets. Made of a ferromagnetic material having a number equal to the sum of the number of S poles and the number of N poles that are long in the axial direction of the permanent magnet and arranged on the inner peripheral surface of the permanent magnet. A magnetized terminal, and a coil that is wound around each of the magnetized terminals and is opposed to the outer peripheral end face of each of the magnetized terminals when energized to magnetize the permanent magnet material to be the permanent magnet. In each of the magnetizing devices of the encoder for the rotational speed detecting device, each of the magnetized terminals has a narrow inner peripheral side portion compared to an outer peripheral end facing the inner peripheral surface of the permanent magnet material. A magnetizing device for an encoder for a rotational speed detecting device, wherein the coil is wound around the inner peripheral side portion.

Images