JP2007057049A - Bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive bearing with a sensor, having superior rotation measuring accuracy with a simple constitution. <P>SOLUTION: In this bearing with the sensor comprising a pair of bearing rings 2, 4 relatively rotatably disposed in opposition to each other, a plurality of rolling elements 6 rollably incorporated between raceway surfaces 2b, 4b respectively formed on opposite faces 2a, 4a of the bearing rings, a cage 8 for rollably retaining the plurality of rolling elements, and a sensor 30 for measuring a rotating state of a bearing, the cage is made of a magnetic material, and the sensor is mounted on one of the bearing rings, and comprises a permanent magnet 34 axially magnetized, and a detecting element 32 disposed in opposition to the cage and detecting change of magnetic field. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sensor-equipped bearing having a sensor function for measuring a rotation state (for example, a rotation speed, a rotation speed, etc.) of the bearing.

  Conventionally, various types of sensor functions for measuring the rotation state of a bearing (for example, rotation speed, rotation speed, etc.) such as a rolling bearing used in an electric power steering device or a wheel support device of an automobile. A sensor-equipped bearing is known (see Patent Document 1).

  As a configuration of the sensor-equipped bearing, for example, a bearing as shown in FIG. 5 is provided on a pair of bearing rings (inner ring 2 and outer ring 4) opposed to each other so as to be relatively rotatable and opposed surfaces 2a and 4a of the respective bearing rings. There are provided a plurality of rolling elements 6 rotatably incorporated between the formed raceway surfaces 2b and 4b, and a holder 8 for holding the plurality of rolling elements 6 one by one so as to be freely rotatable. In this case, the inner ring 2 is a rotating wheel that rotates together with a rotating shaft (not shown) of the bearing, and the outer ring 4 is a stationary wheel that is always maintained in a non-rotating state. Further, a sealing plate 10 (for example, a shield) is interposed between the inner ring 2 and the outer ring 4, so that foreign matter (for example, water or dust) enters from the outside of the bearing or lubricant from the inside of the bearing. (For example, lubricating oil and grease) are prevented from leaking.

  The inner ring 2 that is a rotating wheel is provided with a multi-pole magnetized ring-shaped magnet 20, and the outer ring 4 that is a stationary ring detects a change in magnetic field (for example, the strength or direction of the magnetic field). A sensor 24 (for example, a Hall element) is provided. The magnet 20 is attached to the inner ring 2 via a core bar 22, while the sensor 24 is attached to the outer ring 4 via a sensor case fixing ring 28 while being stored in the sensor case 26. In this case, a hole 26a is formed in the sensor case 26 at a portion facing the magnet 20, and the sensor 24 has a detecting portion 24a facing the magnet 20 through the hole 26a. As the magnet 20 (annular magnet magnetized with multiple poles), for example, a bonded magnet in which N poles and S poles are alternately magnetized in the circumferential direction, N poles and S poles and no poles, or S poles and N poles. A bond magnet in which poles and poles are alternately magnetized can be used.

  When the inner ring 2 rotates in this state, the magnet 20 also rotates together with this, so that the positions of the magnetic poles (for example, N pole and S pole) with respect to the sensor 24 change alternately and continuously. By detecting the change in the magnetic field (change in the magnetic flux density) at this time by the sensor 24, it is possible to measure the rotation speed, rotation speed, and the like of the rotating wheel (inner ring 2) of the bearing.

  However, in the conventional bearing with a sensor, the magnet 20 must be attached to the inner ring 2 and the sensor 24 must be attached to the outer ring 4, which is troublesome and increases the number of parts for attachment. Cost will rise. Further, in order to accurately measure the rotation speed and rotation speed of the rotating wheel (inner ring 2) of the bearing, it is necessary to detect the change in the magnetic field more finely. For this reason, it is preferable to magnetize the magnet 20 provided on the inner ring 2, but in order to magnetize the magnet 20, extra processing costs are generated compared to, for example, the case of two-pole magnetization. End up.

  Moreover, as a structure of a bearing with a sensor, the following bearings are mentioned as an example other than the bearing of a structure as shown in FIG. 5 mentioned above. In such a bearing, one bearing ring (e.g., outer ring) that is a stationary ring is provided with a sensor and a magnet with a single pole magnetized, and the other bearing ring (e.g., inner ring) that is a rotating ring is It extends in the axial direction, and a serrated serrated portion is formed in the extended portion.

  When the inner ring rotates in this state, the unevenness of the serrated serrations changes alternately and continuously in the rotation direction, resulting in a change in magnetic field (change in magnetic flux density). By detecting this change in the magnetic field with a sensor, the rotational speed or rotational speed of the rotating wheel (inner ring) of the bearing can be measured.

Such a bearing with a sensor is provided with a sensor and a magnet only on one of the race rings (for example, the outer ring), so that the mounting cost of these parts can be reduced, but the other race ring (for example, the inner ring) Is stretched in the axial direction, and the stretched portion (serration portion) needs to be formed in a sawtooth shape, which causes an extra processing cost.
JP 2002-40037 A

  The present invention has been made to solve such problems, and an object thereof is to provide an inexpensive sensor-equipped bearing with a simple configuration and excellent rotational measurement accuracy.

  In order to achieve such an object, the sensor-equipped bearing according to the present invention is provided between a pair of race rings arranged to face each other so as to be relatively rotatable, and raceway surfaces respectively formed on opposing surfaces of the race rings. A sensor-equipped bearing comprising a plurality of rolling elements incorporated in a freely rotatable manner, a cage for holding the plurality of rolling elements in a freely rotatable manner, and a sensor for measuring a rotation state of the bearing. The sensor is formed of a magnetic material, and includes a permanent magnet that is provided on one of the races and is magnetized in the axial direction, and a detection element that is disposed to face the cage and detects a change in the magnetic field.

  Further, the sensor-equipped bearing according to the present invention includes a pair of bearing rings arranged to face each other so as to be relatively rotatable, and a plurality of rolling rings incorporated between the raceways formed on the facing surfaces of the respective bearing rings. A bearing with a sensor comprising a rolling element, a cage that holds a plurality of rolling elements in a freely rolling manner, and a sensor that measures the rotational state of the bearing, wherein the cage is made of a non-magnetic material. In addition, each rolling element is formed of a magnetic material, and a sensor is provided on one of the race rings, and a permanent magnet that is magnetized in the axial direction and a detection element that is disposed facing the rolling element and detects a change in the magnetic field. And.

  According to the present invention, it is possible to provide an inexpensive sensor bearing with a simple configuration and excellent rotation measurement accuracy.

Hereinafter, a sensor-equipped bearing according to an embodiment of the present invention will be described with reference to the accompanying drawings.
In addition, although a thrust bearing and a radial bearing can be applied as a bearing, for example, a radial bearing is assumed as an example here. Moreover, as a rolling element, although a roller and a ball | bowl can be applied, a ball | bowl is assumed as an example here.
In this case, the same components as those of the conventional sensor-equipped bearing (FIG. 5) are denoted by the same reference numerals in the drawing, and the description thereof is omitted.

FIGS. 1A and 1B show a sensor-equipped bearing according to a first embodiment of the present invention.
Such a sensor-equipped bearing is provided between a pair of race rings (an inner ring 2 and an outer ring 4) arranged to face each other so as to be relatively rotatable, and raceway surfaces 2b and 4b formed on opposing surfaces 2a and 4a of the raceways. A plurality of rolling elements 6 incorporated so as to be capable of rolling, a cage 8 that holds the plurality of rolling elements 6 one by one so as to freely roll, and a sensor 30 that measures the rotational state of the bearing are provided. In this case, the inner ring 2 is a rotating wheel that rotates together with a rotating shaft (not shown) of the bearing, whereas the outer ring 4 is a stationary wheel that is always maintained in a non-rotating state.

  In such a configuration, the cage 8 is formed of a magnetic material (for example, a mild steel material or an S to C material (carbon steel material for mechanical structure)), and the sensor 30 is provided on the outer ring 4 and is axially And a detection element (for example, Hall IC) 32 that is disposed opposite to the cage 8 and detects a change in the magnetic field. The sensor 30 is connected to a control / arithmetic device (not shown) and a power supply device (not shown) outside the bearing by cables 38, receives power from the power supply device to the Hall IC 32, and detects the detected signal. The data is transmitted from the Hall IC 32 to the control / arithmetic apparatus.

  In the present embodiment, the outer ring 4 has a protruding portion 40 formed by extending one end side 4c of the end portions 4c and 4d in the axial direction from the other end side 4d, and the protruding portion 40 faces the outer ring 4. It is arranged so as to protrude in the axial direction from the end portion 2 c of the inner ring 2, and a sensor 30 is provided on the protruding portion 40. Note that no projecting portions are provided at both end portions 2c and 2d of the inner ring 2, and for the inner ring 2, for example, a ring having a bearing width similar to that of a conventional one (track ring) can be used.

In this case, the protrusion 40 of the outer ring 4 is provided with a groove 40a along the circumferential direction at the end of the surface 4a facing the inner ring 2, and an annular mounting plate (holder) 36 has an outer diameter. Is attached by, for example, fitting into the groove 40a, and the permanent magnet 34 has one circumferential position on the inner surface of the holder 36 (the surface facing the bearing inside) with its magnetic pole surface facing the axial direction. Attached (for example, glued). Further, the Hall IC 32 is attached (for example, bonded) to the surface opposite to the attachment surface of the permanent magnet 34 with respect to the holder 36 so that the detection unit 32a faces the cage 10. As described above, the Hall IC 32 is positioned and arranged on the inner side of the bearing than the permanent magnet 34.
The permanent magnet 34 does not need to be a multi-pole magnetized permanent magnet. For example, a permanent magnet magnetized with two poles in the axial direction can be used. In the present embodiment, as an example, a two-pole magnet is used. The magnetized permanent magnet is arranged with the S pole on the Hall IC 32 side and the N pole on the holder 36 side.

  Further, in the present embodiment, the cage 8 presses the steel plate so that the pockets 8a that hold the rolling elements 6 and the flat portions 8b that connect the adjacent pockets 8a are alternately arranged along the circumferential direction. Two cage halves formed by molding are riveted and formed at the flat portion 8b so as to face each other (so-called corrugated press cage).

  Here, the case of measuring the rotation state (for example, the rotation speed and the rotation speed) of the bearing will be considered below. In the present embodiment, when the inner ring 2 rotates, the retainer 8 also rotates together with the inner ring 2, and during the rotation, the retainer 8 has a permanent magnet 34 with the outer peripheral portion of the pocket 8 a and the flat portion 8 b alternately through the Hall IC 32. Opposite. In this case, since the outer peripheral portion of the pocket 8a of the cage 8 protrudes more outwardly of the bearing than the flat portion 8b by the radius of the rolling element 6, the distance between the cage 8 and the permanent magnet 34 is constant. Without repeated.

  For example, in the state shown in FIG. 1A, the retainer 8 is in a state where the outer peripheral portion of the pocket 8a faces the permanent magnet 34 while maintaining the distance d1, and is closest to the permanent magnet 34. On the other hand, in the state shown in FIG. 1 (b), the retainer 8 is in a state in which the flat portion 8 b faces the permanent magnet 34 while maintaining the distance d 2 and is farthest from the permanent magnet 34. That is, during the rotation of the inner ring 2 (the cage 8), the distance between the cage 8 and the permanent magnet 34 repeatedly varies between the minimum value d1 and the maximum value d2.

  In the present embodiment, since the cage 8 is formed of a magnetic material, a magnetic field is generated between the cage 8 and the permanent magnet 34. However, if the distance between the cage 8 and the permanent magnet 34 is repeatedly changed between the minimum value d1 and the maximum value d2 due to the rotation of the inner ring 2 (the cage 8), the cage 8 The strength of the magnetic field (magnitude of magnetic flux density) generated between the permanent magnet 34 also fluctuates repeatedly. For example, in FIG. 4, seven rolling elements (balls) are incorporated in a bearing with a sensor (bearing inner diameter d: φ8 (mm), bearing outer diameter D: φ22 (mm), bearing width B: 7 (mm)). In this case, a change in magnetic flux density (change in pulse signal) during one rotation of the cage is shown as an example.

Therefore, by detecting the change in magnetic field (change in magnetic flux density) at this time by the Hall IC 32, the rotational speed, rotational speed, etc. of the rotating wheel (inner ring 2) of the bearing can be measured. Incidentally, nc (revolution speed of the rolling elements 6) the rotational speed of the cage 8 is not coincident with the rotational speed n _i of the rotary wheel (inner ring 2), for example, in the case of the inner ring rotation, the both following relationship There are, it is possible to convert the rotational speed n _c of the cage 8 to the rotational speed n _i of the rotary wheel (inner ring 2) by using this relation.
n _c = (1−γ) · (n _i / 2) (where γ = D _a · cos α / D _p )
(D _a : diameter of rolling element (ball), D _p : pitch circle diameter of the ball (PCD: Pitch Circle Diameter), α: contact angle of the ball)

As described above, according to the sensor-equipped bearing of the present embodiment, the sensor 30 (the Hall IC 32 and the single pole (two poles) magnetized permanent magnet 34) is attached to one of the race rings (outer ring 4), and the other race ring ( By using a ring (orbital ring) having a bearing width similar to the conventional one for the inner ring 2), it is possible to provide an inexpensive sensor-equipped bearing that has a simple configuration and excellent rotational measurement accuracy.
Further, since the cage 8 is formed of a magnetic material, the degree of freedom in production such as the shape and size of the cage 8 is high, and the cage 8 can be of any shape and size. The magnetic field change (change in magnetic flux density) with the permanent magnet 34 during the rotation of the magnetic field can be easily increased. For this reason, it is possible to provide a sensor-equipped bearing having excellent reliability with few detection errors (pulse signal reading errors) of magnetic field change in the sensor 30 (Hall IC 32).

In the present embodiment described above, only one of the race rings (outer ring 4) has a protruding portion 40 formed by extending one end side 4c of the end portions 4c, 4d in the axial direction from the other end side 4d. The two bearing rings (inner ring 2 and outer ring 4) having different bearing widths are used. However, the same effect can be obtained by using a sensor bearing (modified example) as shown in FIG. Obtainable.
In this modification, the inner ring 2 has a protruding portion 42 formed by extending one end side 2c of the end portions 2c, 2d in the axial direction from the other end side 2d. At this time, the inner ring 2 and the outer ring 4 have the same bearing width by extending in the axial direction as much as the one end side 4 c of the outer ring 4 to form the protruding portion 42.

In this case, a sealing plate 44 (for example, a seal or a shield) is interposed between the protruding portion 40 of the outer ring 4 and the protruding portion 42 of the inner ring 2, and the outer diameter of the sealing plate 44 is the outer ring 4. The inner diameter of the inner ring 2 extends toward the protrusion 42 of the inner ring 2. The sealing plate 44 is also interposed between the inner and outer rings on the opposite side of the protruding portions 40 and 42 with the rolling element 6 interposed therebetween.
In this modified example, the sealing plate 44 not only prevents intrusion of foreign matters (for example, water and dust) from the outside of the bearing and leakage of lubricant (for example, lubricating oil and grease) from the inside of the bearing, but also the sensor 30. Also serves as an attachment plate (holder) for attaching the outer ring 4 to the projecting portion 40 of the outer ring 4, and the permanent magnet 34 faces the inner surface of the sealing plate 44 (the surface facing the inner side of the bearing) with its magnetic pole surface facing in the axial direction. ) Is attached (for example, adhered) in one circumferential direction, and the Hall IC 32 is opposite to the attachment surface of the permanent magnet 34 with respect to the sealing plate 44 with the detection unit 32a facing the retainer 10. Are attached (eg, bonded) to the surface.

  The sealing plate 44 is preferably made of metal in consideration of strength. However, if the sealing plate 44 is weak even if it is energized, it affects the Hall IC 32 (for example, the detection accuracy of the magnetic field change is reduced or the detection signal is detected). Therefore, the influence on the Hall IC 32 can be suppressed by using a material (for example, resin) having excellent non-conductivity (insulation). For example, by forming only the mounting portion of the sensor 30 with resin and forming the remaining portion with metal, a sealing plate having both strength and insulation can be obtained.

  As described above, according to the sensor-equipped bearing of the present modification, in addition to the above-described effects, it is not necessary to prepare a bearing ring with a different bearing width, and only a bearing ring with a single bearing width can be prepared. 30 (Hall IC 32 and permanent magnet 34) can be stored inside the bearing, and these can be integrated with the bearing, so that the bearing can be easily handled.

  In the first embodiment and the modification described above, the material of the rolling element 6 is not particularly limited. However, for example, the rolling element 6 of any material such as an alloy such as high carbon chromium bearing steel or ceramic is applied. Can do. Further, in the first embodiment and the modification described above, only one sensor 30 is provided on the outer ring 4 that is a stationary wheel (provided at one place in the circumferential direction of the facing surface 4a). For example, two sensors 30 are provided at two locations in the circumferential direction with a predetermined phase, and the phase difference between magnetic field changes (pulse signals) detected by the two sensors 30 (Hall IC 32) is detected. By reading, the rotation state of the bearing (for example, the rotation speed, the rotation speed, etc.) can be measured with higher accuracy.

  In the first embodiment and the modification described above, the holder 36 or the sealing plate 44 is attached to the surface 4a of the stationary wheel (outer ring 4) facing the rotating wheel (inner ring 2). It is not limited, For example, you may attach to the side surface by the side of the edge part 4c of a stationary ring (outer ring | wheel 4). In the first embodiment described above, the sealing plate is not interposed between the inner and outer rings. However, for example, the sealing plate may be interposed between the inner and outer rings opposite to the holder 36 with the rolling element 6 interposed therebetween. . Further, in the above-described modification, the sensor 30 (Hall IC 32 and permanent magnet 34) is attached to the sealing plate 44. However, instead of this, for example, the sensor 30 may be attached to the same holder 36 as in the first embodiment. .

FIGS. 3A to 3C show a sensor-equipped bearing according to the second embodiment of the present invention. In the following description, the same components as those of the sensor-equipped bearing according to the first embodiment (FIGS. 1A and 1B) are denoted by the same reference numerals in the drawings, and the description thereof is omitted. To do.
In such a sensor-equipped bearing, the cage 8 is made of a nonmagnetic material (for example, synthetic resin or ceramic), and the rolling element 10 is made of a magnetic material (for example, bearing steel or martensitic stainless steel). Yes.

  In the present embodiment, the cage 8 is alternately provided with pockets 8a for holding the rolling elements 6 and column portions 8c for connecting adjacent pockets 8a along the circumferential direction. In this case, the cage 8 has a crown shape in which one side has an opening k for inserting each rolling element 6 into the pocket 8a and the other side is closed (a so-called crown-shaped cage). Note that a pair of claw portions t protruding so as to partially cover the opening k are provided on the column portion 8c of the cage 8, and the rolling elements 6 inserted into the pockets 8a are separated by the claw portions t. It is held in the pocket 8a in a sandwiched state.

  Here, the case of measuring the rotation state (for example, the rotation speed and the rotation speed) of the bearing will be considered below. In the present embodiment, when the inner ring 2 rotates, the cage 8 and the rolling element 6 also rotate together with this, and during the rotation, the rolling element 6 and the column portion 8c of the cage 8 alternately pass through the Hall IC 32 and the permanent magnet 34. Opposite. In this case, as shown in FIG. 3C, since the rolling elements 6 are held in the pockets 8a of the cage 8 with a predetermined interval, the rolling elements 6 and the permanent magnet 34 have a predetermined period. They are opposed to each other, and both repeat a facing state and a non-facing state.

  For example, in the state shown in FIG. 3A, the rolling element 6 faces the permanent magnet 34 while maintaining the distance d3 and is closest to the permanent magnet 34 (opposed state). On the other hand, in the state shown in FIG. 3B, since the column portion 8c of the cage 8 faces the permanent magnet 34 while maintaining the distance d4, the rolling element 6 does not face the permanent magnet 34 (non-facing). State). That is, during the rotation of the inner ring 2 (the rolling element 6), the relative positional relationship between the rolling element 6 and the permanent magnet 34 repeatedly varies from a state where they face each other at a minimum distance d3 to a state where they do not face each other at all.

  In the present embodiment, since the rolling element 6 is made of a magnetic material, a magnetic field is generated between the rolling element 6 and the permanent magnet 34. However, when the relative positional relationship between the rolling element 6 and the permanent magnet 34 repeatedly fluctuates due to the rotation of the inner ring 2 (the rolling element 6), this occurs between the rolling element 6 and the permanent magnet 34. The strength of the magnetic field (the magnitude of the magnetic flux density) also fluctuates repeatedly. Therefore, by detecting the change in magnetic field (change in magnetic flux density) at this time by the Hall IC 32, the rotational speed, rotational speed, etc. of the rotating wheel (inner ring 2) of the bearing can be measured. The revolution number of the rolling element 6 (the number of rotations of the cage 8) does not match the revolution number of the rotating wheel (inner ring 2), but the revolution number of the rolling element 6 is the same as in the case of the first embodiment described above. The number can be converted into the number of rotations of the rotating wheel (inner ring 2).

As described above, according to the sensor-equipped bearing of the present embodiment, the sensor 30 (the Hall IC 32 and the single pole (two poles) magnetized permanent magnet 34) is attached to one of the race rings (outer ring 4), and the other race ring ( By using a ring (orbital ring) having a bearing width similar to the conventional one for the inner ring 2), it is possible to provide an inexpensive sensor-equipped bearing that has a simple configuration and excellent rotational measurement accuracy.
Further, the play (for example, rattling) of the rolling element 6 that rolls while being held in the pocket 8a of the cage 8 is compared with the play (for example, rattling) of the cage 8 that rotates between the inner and outer rings. Because the rolling element 6 is made of a magnetic material and the cage 8 is made of a non-magnetic material, the magnetic field can be changed with a stable cycle (stable pulse signal interval) during the rotation of the bearing. Can do. For this reason, it is possible to provide a sensor-equipped bearing having excellent reliability with few detection errors (pulse signal reading errors) of magnetic field change in the sensor 30 (Hall IC 32).

  Further, in the present embodiment, a crown-shaped cage 8 is used as the cage, and the cage 8 has an opening side (for example, on the right side of the cage shown in FIGS. 3A and 3B). Since the space in the bearing can be secured, the bearing with sensor is made compact by positioning the opening side of the cage 8 on the side where the sensor 30 (Hall IC 32, permanent magnet 34) is attached. be able to. Further, since the rolling element 6 is held in the pocket 8a while being held by the claw portion t of the cage 8, the rolling element 6 is not rattled, and the sensor 30 (Hall IC 32, permanent magnet 34) is extremely rolled. The sensor 30 does not interfere (contact) with the rolling element 6 even if the sensor 30 is disposed near the roller 6. For this reason, the sensor-equipped bearing can be further downsized.

  In the second embodiment described above, only one sensor 30 is provided on the outer ring 4 that is a stationary wheel (provided at one place in the circumferential direction of the facing surface 4a), but instead, a plurality of sensors 30 are provided. For example, two sensors 30 are provided at two locations in the circumferential direction with a predetermined phase, and the phase difference between magnetic field changes (pulse signals) detected by the two sensors 30 (Hall IC 32) is read. The rotation state of the bearing (for example, the number of rotations and the rotation speed) can be measured with higher accuracy. In the second embodiment described above, the holder 36 is mounted on the surface 4a of the stationary wheel (outer ring 4) facing the rotating wheel (inner ring 2), but the mounting position is not particularly limited. You may attach to the side surface by the side of the edge part 4c of the outer ring | wheel 4). In the second embodiment described above, the projecting portions 42 and 40 are not formed on the race rings (the inner race 2 and the outer race 4). Instead, for example, only one race race (the outer race 4) is provided. The protrusions 40 may be formed, and the protrusions 40 and 42 may be formed on both race rings (the inner ring 2 and the outer ring 4) (see FIGS. 1A, 1B, and 2). In the second embodiment described above, the sealing plate is not interposed between the inner and outer rings. However, for example, the sealing plate may be interposed between the inner and outer rings on the opposite side of the holder 36 with the rolling element 6 interposed therebetween. . Further, in the second embodiment described above, the sensor 30 (Hall IC 32 and permanent magnet 34) is attached to the holder 36, but instead of this, for example, a sealing plate 44 similar to the above-described modification (see FIG. 2). You may attach to.

In the first embodiment, the modified example, and the second embodiment described above, the sensor 30 has the permanent magnet 34 attached to the holder 36 or the sealing plate 44, the Hall IC 32 attached to the permanent magnet 34, and the cage 10 or the rolling plate. Although it was made to oppose the moving body 6, the attachment position of Hall IC32 and the permanent magnet 34 may be reverse. That is, the Hall IC 32 may be attached to the holder 36 or the sealing plate 44, and the permanent magnet 34 may be attached to the Hall IC 32, and may be opposed to the cage 10 or the rolling element 6.
In this case, a magnetic circuit returning from the permanent magnet 34 to the permanent magnet 34 through the cage 10 (rolling element 6), the holder 36 (sealing plate 44), and the Hall IC 32 is formed (permanent magnet 34 and holding). A magnetic field is generated between the container 10 and the rolling element 6). In this state, when the rotating wheel (inner ring 2) of the bearing rotates, the distance (relative positional relationship) between the cage 8 (rolling element 6) and the permanent magnet 34 repeatedly fluctuates during the rotation. 8 (rolling element 6) and the permanent magnet 34 change the magnetic field (magnetic flux density), so that the change in the magnetic field (change in magnetic flux density) can be detected by the Hall IC 32.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structural example of the bearing with a sensor which concerns on 1st Embodiment of this invention, Comprising: (a) is sectional drawing which shows the state which the holder | retainer and the permanent magnet approached most, (b) is a holder | retainer Sectional drawing which shows the state from which the magnet and the permanent magnet were most separated. Sectional drawing which shows the structural example of the bearing with a sensor which concerns on the modification of this invention. It is a figure which shows the structural example of the bearing with a sensor which concerns on 2nd Embodiment of this invention, Comprising: (a) is sectional drawing which shows the state which the rolling element and the permanent magnet approached most, (b) is a rolling element. Sectional drawing which shows the state in which the magnet and the permanent magnet were most separated, (c) is a top view which shows the positional relationship of a sensor and a rolling element. The figure which shows the example of a change of the magnetic flux density during one rotation of a bearing. Sectional drawing which shows the structural example of the conventional bearing with a sensor.

Explanation of symbols

2 Inner ring 4 Outer ring 6 Rolling element 8 Cage 8a Pocket part 8b Flat part 8c Pillar part 30 Sensor 32 Detection element (Hall IC)
32a detector 34 permanent magnet 36 mounting plate (holder)
38 Cable 40, 42 Protrusion 44 Sealing plate d1, d2, d4 Distance between cage and permanent magnet d3 Distance between rolling element and permanent magnet

Claims (2)

A pair of race rings arranged to face each other so as to be rotatable relative to each other, a plurality of rolling elements rotatably incorporated between race surfaces formed on the opposed surfaces of the respective race rings, and a plurality of rolling elements. A sensor-equipped bearing comprising a cage that is movably held and a sensor that measures a rotation state of the bearing,
The cage is made of a magnetic material, and the sensor is provided on one of the race rings, and includes a permanent magnet that is magnetized in the axial direction, and a detection element that is disposed opposite to the cage and detects a change in the magnetic field. A sensor-equipped bearing. A pair of race rings arranged to face each other so as to be rotatable relative to each other, a plurality of rolling elements rotatably incorporated between race surfaces formed on the opposed surfaces of the respective race rings, and a plurality of rolling elements. A sensor-equipped bearing comprising a cage that is movably held and a sensor that measures a rotation state of the bearing,
The cage is made of a non-magnetic material, and each rolling element is made of a magnetic material. The sensor is provided on one of the race rings, and is opposed to the permanent magnet magnetized in the axial direction and the rolling element. A sensor-equipped bearing comprising: a detecting element that is disposed and detects a change in a magnetic field.

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