JP2004077159A - Pulser ring and bearing unit having sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulser ring and a bearing unit having a sensor that can facilitate the automation of measurement in rotary swing without adding surplus configurations with the pulser and the bearing unit having a sensor so far conventionally used as bases. <P>SOLUTION: In the bearing unit having a sensor, the pulser ring and a sensor apparatus that opposes the pulse ring are relatively rotated. The N and S poles of a magnetized element 8 in the pulser ring are set to be in a trapezoidal shape. As a result, the width of either the N or S pole is set larger at a part close to the outer periphery of the pulse ring, and the width of the other is set larger at a part closer to the inner periphery. The sensor apparatus has a run-out detection section for detecting the deviation of a rotor based on a change in magnetic force in the peripheral direction of the pulser ring. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulser ring constituting a rotational speed sensor used in an automobile ABS or the like, and a sensor-equipped bearing unit having the pulser ring.
[0002]
[Prior art]
In a railway vehicle or an automobile, in order to support an axle or a rotating shaft that transmits rotation to the axle and to detect a rotating speed of the axle, a plurality of such elements are arranged with one N pole and one S pole as one element. A bearing unit with a sensor in which a pulsar ring that outputs a rotation signal and a sensor device that has a magnetic sensor disposed opposite to the pulsar ring and a signal processing unit that performs signal processing based on an output from the magnetic sensor are relatively rotated. However, since this unit cannot detect the run-out of the bearing, conventionally, the measurement of the run-out of the bearing has been performed by using a micro gauge or the like.
[0003]
[Problems to be solved by the invention]
The above-described conventional method for measuring rotational runout has a problem that an extra gauge is required and automation is difficult.
[0004]
An object of the present invention is to provide a pulser and a sensor-equipped bearing unit that can easily automate the measurement of rotational runout without adding an extra configuration, based on a conventionally used pulser and a sensor-equipped bearing unit. It is in.
[0005]
Means for Solving the Problems and Effects of the Invention
According to the pulsaring according to the present invention, in a pulsaring in which a plurality of elements are arranged with one N-pole and one S-pole as one element and a rotation signal is output, one element of the pulsaring includes an N-pole and an S-pole in a portion closer to the outer periphery. The width of one of the poles is increased, and the width of the other pole is increased in the portion closer to the inner periphery.
[0006]
A bearing unit with a sensor according to the present invention includes a pulsar ring in which one N pole and one S pole are arranged as one element and a plurality of these elements are arranged to output a rotation signal, a magnetic sensor and a magnetic sensor arranged to face the pulsar ring In a bearing unit with a sensor in which a sensor device having a signal processing means for performing signal processing based on the output from the sensor unit is relatively rotated, one of the pulsar rings has an N-pole and an S-pole in a portion closer to the outer periphery. The width of one of them is increased, and the width of the other is increased in the portion closer to the inner periphery, and the sensor device detects the eccentricity of the rotating body based on the magnetic force change in the circumferential direction of the pulsar ring. Characterized by having a portion.
[0007]
The magnetized body has flexibility, for example, a rubber-like elastic body. The magnetized body can be obtained, for example, by cutting a sheet-shaped rubber magnetic body into a band shape. In this case, the magnetization may be performed on the sheet-shaped magnetic body, or may be performed after cutting into a strip shape. The strip-shaped magnetized body is cut so as to have a length corresponding to the peripheral length of the support member, and is then attached over substantially the entire periphery of the support member.
[0008]
For one element of the pulsaring, the width of one of the N-pole and the S-pole is increased in the outer portion and the width of the other is increased in the inner portion. For example, the shape of one pole may be trapezoidal (equilateral trapezoidal), and the shape of one element may be a parallelogram. Also, the shape of one pole may be a triangle (an isosceles triangle, a right triangle, etc.) instead of a trapezoid, and the waveform, that is, the boundary between the north pole and the south pole may be a sine curve.
[0009]
According to the pulsaring of the present invention, for one element of the pulsaring, the width of one of the N-pole and the S-pole is increased in the portion closer to the outer periphery, and the width of the other is increased in the portion closer to the inner periphery. When the distance from the center of the bearing to the center of each magnetic pole changes due to the presence of runout in the bearing, where the distance is large, the magnetic force of either the S pole or the N pole is reduced. Strongly, when the distance is small, the magnetic force of the same magnetic pole becomes weak, and the magnetic force changes along the circumferential direction compared to the case where each magnetic pole is formed such that outer circumference = center = inner circumference. Becomes larger. Therefore, it is sensitive to shake, and highly accurate center shake information can be extracted. This pulsaring can be obtained by changing the shape of one pole from a square to, for example, a trapezoid, while keeping the overall shape of the belt-shaped magnetized body forming the conventional pulsaring, and reducing the rotation speed. Since the same rotation signal as that of the conventional pulser ring can be output as the detection signal, the pulser ring used in the conventional bearing unit with a sensor can be easily replaced with the pulser ring of the present invention.
[0010]
According to the bearing unit with a sensor of the present invention, for one element of the pulsar ring, the width of one of the N pole and the S pole is increased in the portion closer to the outer periphery, and the width of the other is increased in the portion closer to the inner periphery. If the distance from the center of the bearing to the center of each magnetic pole changes due to the presence of run-out in the bearing, where the distance is large, one of the S-pole and the N-pole is used. When the distance is small, the magnetic force of the same magnetic pole becomes weaker, and the magnetic force along the circumferential direction is smaller than that in the case where each magnetic pole is formed such that the outer peripheral portion = the central portion = the inner peripheral portion. The magnetic force change becomes large. Therefore, it is sensitive to shake, and highly accurate center shake information can be extracted. Note that the amount of increase in vibration due to the load can be detected by obtaining the amplitude ratio (A / B) and comparing the initial amplitude ratio with the amplitude ratio increased by the load. This pulsaring can be obtained by changing the shape of one pole from a square to, for example, a trapezoid, while keeping the overall shape of the belt-shaped magnetized body forming the conventional pulsaring, and reducing the rotation speed. Since the same rotation signal as that of the conventional pulser ring can be output as the detection signal, the pulser ring used in the conventional bearing unit with a sensor can be easily replaced with the pulser ring of the present invention. In this way, it is possible to obtain a bearing unit with a sensor that can detect the rotation speed, the angle, and the like, can extract the center runout information, and can easily perform automatic control.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
FIG. 1 shows the upper half of one embodiment of a bearing unit with a sensor according to the present invention. In the following description, left and right refer to left and right in the figure.
[0013]
As shown in FIG. 1, the rolling bearing unit with a sensor includes a rolling bearing (1), a sensor device (2) provided on the rolling bearing (1), and a pulsar ring (3) that is a detected portion.
[0014]
The rolling bearing (1) includes an outer ring (4) that is a fixed ring, an inner ring (5) that is a rotating ring, and balls (6) that are a plurality of rolling elements disposed therebetween. Although not shown, the outer ring (4) is fixed to a housing or the like, and the inner ring (5) is fixed to a rotating shaft or the like.
[0015]
The pulsar ring (3) includes a support member (7) fixed to the inner ring (5) and a magnetized body (8) fixed to the support member (7). The support member (7) includes a small-diameter cylindrical portion (7a) fitted over the outer periphery of the inner ring (5), and a perforated disk portion (flange portion) extending radially outward from the right end of the small-diameter cylindrical portion (7a). (7b) and a large-diameter cylindrical portion (7c) extending rightward from the outer peripheral edge of the perforated disk portion (7b), and form a ring as a whole.
[0016]
An annular seal groove (9) is formed at the shoulder of the inner diameter at the right end of the outer ring (4). The outer peripheral edge of the contact seal (10) is fitted into the seal groove (9), and the inner peripheral edge of the seal (10) is the left end of the small-diameter cylindrical portion (7a) of the support member (7) of the pulsaring (3). Is in contact with
[0017]
The sensor device (2) includes a case (11) fixed to the outer ring (4), a sensor (12) provided in the case (11), and a signal for performing signal processing based on an output from the sensor (12). Processing means (13). As the sensor (12), a magnetic sensor such as a Hall element sensor or a magnetoresistive (MR) element sensor is used.
[0018]
The case (11) is composed of a short cylindrical outer peripheral wall (11a) and an inner peripheral wall (11b), and a perforated disk-shaped side wall (11c) connecting these right ends to each other. The cross section of the hollow portion is substantially U-shaped. The free end (left end) of the outer peripheral wall (11a) extends leftward from the inner peripheral wall (11b), and the free end of the outer peripheral wall (11a) is tightly fitted to the shoulder at the right end of the outer ring (4). The free end of the inner peripheral wall (11b) is close to the right end face near the inner diameter of the inner ring (5).
[0019]
As shown in FIG. 2, the pulsaring ring (3) has a magnetized body (8) which is formed in a band shape such that the magnetic poles on the front side are alternately N-poles and S-poles at an equal pitch. (8) is formed by fixing the entire outer peripheral surface of the support member (7) with its ends facing each other. Each N pole and each S pole are trapezoidal shaped, and when one N pole and one S pole are considered as one element, the shape of this element is a parallelogram. The pulsar ring (3) is formed by arranging a plurality of these elements without gaps.
[0020]
The end of the magnetized body (8) has an end face inclined with respect to a plane perpendicular to the length direction since each pole is in the shape of an equilateral trapezoid, so that an error may occur in the manufacturing process. Even if there is, an extreme magnetic change in the abutting portion (J) is prevented, so that noise caused by the discontinuous portion is suppressed.
[0021]
As shown in FIG. 3, the rotation signal output from the pulser ring (3) is detected by a magnetic sensor (12), further amplified by an amplifier (14), and output to a processing unit of a signal processing unit. You. The processing unit includes a rotation speed detection unit that detects the rotation speed of the inner ring (5) based on a change in the circumferential magnetic force of the pulsar ring (3), and an inner ring (based on a change in the circumferential magnetic force of the pulsar ring (3)). Since each N-pole and each S-pole provided with the center runout detecting unit for detecting the eccentricity of 5) are in the shape of an equilateral trapezoid, one element of the pulsaring (3) is shown in FIG. In the part indicated by (), the width of the S pole of the N pole and the S pole is increased. In the part indicated by III in FIG. 4 (the part closer to the inner circumference), the width of the N pole is increased. Has been made big. In the central portion indicated by II in FIG. 4, the widths of the north pole and the south pole are equal to each other. Therefore, when the change in magnetic force is graphed with the N pole taken as positive, the magnitude A of the magnetic force due to the N pole is small and the magnitude B of the magnetic force due to the S pole is small in the portion near the outer periphery as shown in FIG. As shown in FIG. 4 (II), the magnitude of the magnetic force A due to the N-pole and the magnitude B of the magnetic force due to the S-pole are equal at the center portion, as shown in FIG. 4 (III). In the deviated portion, the magnitude A of the magnetic force due to the N pole is large, and the magnitude B of the magnetic force due to the S pole is small.
[0022]
When the eccentricity is zero, the pulser ring (3) thus formed outputs the magnetic force shown in FIG. 4 (II). FIG. 5 shows a change in magnetic force when there is eccentricity. In FIG. 5, the graph (1) has zero eccentricity, that is, the same graph as FIG. 4 (II). The graph of (2) shows a case where there is eccentricity, and shows a case where, from the left to the right of the figure, first, it shifts upward, that is, toward the outer periphery, and thereafter, shifts downward, that is, toward the inner periphery. I have. Regarding the magnetic pole length of (2), the leftmost N pole in the figure is slightly longer than that of (1), the second S pole from the left is also longer, and the third N pole from the left is Short, the fourth south pole from the left is slightly longer, the fifth north pole from the left is short, the sixth south pole from the left is short, the seventh north pole from the left is long, and the eighth south pole from the left. Is shorter. Accordingly, as shown in the graph of (2) in the figure, the corresponding graph shows, in order from the left, an N pole having a magnetic force slightly larger (substantially equal) than that of (1), and a graph of (1) S-pole with a larger magnetic force, N-pole with a smaller magnetic force than in (1), S-pole with a larger magnetic force as in (1), N-pole with a smaller magnetic force as in (1), An S-pole with a magnetic force slightly larger (almost equal) than in the case of (1), an N-pole with a larger magnetic force than in the case of (1), and an S-pole with a smaller magnetic force than in (1) Will be.
[0023]
FIG. 6 shows a graph corresponding to FIG. 5 for the conventional pulsaring. In FIG. 6, (3) indicates that the eccentricity is zero, and (4) indicates eccentricity. From this graph, it can be seen that the conventional pulsar ring having a magnetized body formed by repeating rectangular magnetic poles has almost the same graph as the case where the eccentricity is zero even when there is eccentricity.
[0024]
As can be seen from a comparison between FIG. 5 and FIG. 6, the pulsaring of the present invention is formed so that its undulation is easily output when there is eccentricity. Can be obtained. In addition, to detect the shake increased by the load, the amplitude ratio (A ′ / B ′) is obtained. For example, while the initial amplitude ratio A ′ / B ′ = 1.02, A ′ / B ′ = 1. It can be performed by calculating the rate of change from the initial amplitude ratio as if it had deteriorated to 1. This pulsaring can be obtained by changing the shape of one pole from a square to, for example, a trapezoid, while keeping the overall shape of the belt-shaped magnetized body forming the conventional pulsaring, and reducing the rotation speed. Since the same rotation signal as that of the conventional pulser ring can be output as the detection signal, the pulser ring used in the conventional bearing unit with a sensor can be easily replaced with the pulser ring of the present invention. In this way, it is possible to obtain a bearing unit with a sensor that can detect the rotation speed, the angle, and the like, can extract the center runout information, and can easily perform automatic control.
[0025]
Although the pulsar ring (3) is fixed to the inner ring (5) in FIG. 1, the pulsar ring (3) can be fixed to the outer ring (4) for use. Further, the magnetized body may be provided on a flange portion of the support member.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a sensor-equipped bearing unit according to the present invention.
FIG. 2 is a perspective view showing an example of a pulsar ring used in the sensor-equipped bearing unit according to the present invention.
FIG. 3 is a diagram showing a signal processing portion of the sensor-equipped bearing unit according to the present invention.
FIG. 4 is a diagram showing the magnitude of the magnetic force of the pulsaring according to the present invention for each of an outer peripheral portion, a central portion, and an inner peripheral portion.
FIG. 5 is a diagram showing the magnitude of the magnetic force of the pulsaring according to the present invention with and without eccentricity.
FIG. 6 is a diagram showing the magnitude of the magnetic force of a conventional pulsaring with and without eccentricity.
[Explanation of symbols]
(1) Rolling bearing (2) Sensor device (3) Pulser ring (8) Magnetized body (12) Magnetic sensor

Claims (4)

In a pulsar ring in which a plurality of elements are arranged with one N-pole and one S-pole as one element and a rotation signal is output, one of the elements of the pulsar ring has one of the N-pole and the S-pole in a portion closer to the outer periphery. A pulsaring device characterized in that one of the widths is increased, and the width of the other is increased in an inner portion. 2. The pulser according to claim 1, wherein each pole has a trapezoidal shape. A pulser ring in which a plurality of elements are arranged with one N pole and one S pole as one element to output a rotation signal, and a magnetic sensor arranged opposite to the pulsar ring and a signal processing based on an output from the magnetic sensor are performed. In a bearing unit with a sensor in which a sensor device having signal processing means for performing rotation is relatively rotated, one of the N-pole and the S-pole of one element of the pulsar ring is increased in a portion closer to the outer periphery. In the portion closer to the inner periphery, the width of the other is made larger, and the sensor device has a center runout detector that detects the eccentricity of the rotating body based on a change in the magnetic force of the pulsar ring in the circumferential direction. Bearing unit with sensor. The bearing unit with a sensor according to claim 3, wherein each pole has a trapezoidal shape.

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