JP2004264050A - Rolling bearing unit with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely find a load applied onto a bearing by simple constitution, and to detect also a rotational speed of a rotating side track member of the bearing. <P>SOLUTION: A sensor unit 2 has a magnetostrictive sensor 8 provided in a fixed side track member 3 to detect a gap with respect to the rotating side track member 4, and a processing means for processing an output of the magnetostrictive sensor 8. The processing means is provided with a rotation detecting part for finding the rotational speed of the rotating side track member 4, based on the repetition number of output changes of the magnetostrictive sensor 8, an averaging part for averaging the outputs of the magnetostrictive sensor 8, and a load computing part for finding the load applied onto the rolling bearing, based on the output averaged in the averaging part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
The present invention relates to a rolling bearing unit with a sensor in which a rolling bearing and a sensor device for detecting various kinds of information on the rolling bearing are integrated.
[0002]
TECHNICAL FIELD OF THE INVENTION
[0003]
[Prior art]
In an automobile, since various information is required to perform the control, a rotation-side track member to which wheels are attached, a fixed-side track member to be fixed to a vehicle body side, and a track member arranged between both track members It has been proposed to provide a sensor device on a hub unit having two rows of rolling elements.
[0004]
For example, Patent Document 1 discloses a sensor-equipped hub unit in which an annular support member is attached to the inner end surface of a fixed-side track member, and a strain sensor is attached to the annular support member.
[0005]
[Patent Document 1]
JP-A-3-209016
[Problems to be solved by the invention]
2. Description of the Related Art In recent years, in addition to ABS control (anti-lock brake system), driving force control that does not spin drive wheels at the time of starting or accelerating, braking force control that suppresses side slip during cornering, and the like have been implemented as vehicle control means. However, in order to perform more accurate control, it is important to detect data that can be effectively used for these controls.
[0007]
In view of such circumstances, the inventor of the present application has created a problem of accurately measuring the ground contact load of a tire to improve vehicle control.
[0008]
However, since the conventional hub unit with a sensor measures the distortion of the annular support member, an error increases when the ground load is obtained from the distortion, and the ground load is accurately determined from the measured value of the strain sensor. There was a problem that it could not be obtained.
[0009]
An object of the present invention is to obtain a load applied to a bearing with a simple configuration and with high accuracy, and also to detect a rotation speed of a rotating side raceway member of a bearing. Another object of the present invention is to provide a sensor-equipped rolling bearing unit capable of accurately obtaining a ground contact load and a wheel rotation speed with a simple configuration.
[0010]
Means for Solving the Problems and Effects of the Invention
A rolling bearing unit with a sensor according to the present invention includes a rolling bearing having a fixed-side race member, a rotating-side race member, and a rolling element disposed between the two members, and a sensor device provided with a sensor device provided on the rolling bearing. In the rolling bearing unit, the sensor device has a magnetostrictive sensor provided on the fixed-side raceway member to detect a gap between the rotating-side raceway member, and processing means for processing an output of the magnetostrictive sensor, A processing unit configured to determine a rotation speed of the rotation-side track member from the number of repetitions of a change in the output of the magnetostrictive sensor; an averaging unit that averages an output of the magnetostrictive sensor; and obtain a load from the averaged output. And a load calculating unit.
[0011]
The rolling bearing unit with sensor according to the present invention is suitably used for a hub unit of an automobile, but can also be used for a bearing portion for supporting a rotating body of a motor or the like.
[0012]
When used in a hub unit of an automobile, the contact load applied to each tire varies with changes in the speed and attitude of the running vehicle. The gap changes according to the grounding load, and the change in the gap changes the magnetic field near the magnetostrictive sensor, and the magnetostrictive sensor can measure the change in the magnetic field as the magnetostriction variation. Then, the relationship between the magnetostriction variation and the variation in the load on the bearing or the contact load of the tire is determined in advance, and the amount of variation in the load applied to the bearing or the contact load of the tire is calculated from the variation in the magnetostriction. You can ask. The gap changes periodically every one rotation, and the rotation speed of the rotation-side raceway member of the rolling bearing can be obtained by using the number of repetitions of the change in the gap.
[0013]
A magnetostrictive sensor is a sensor that measures an inverse magnetostrictive effect (a phenomenon in which a magnetic force appears when a substance is distorted or deformed). As the magnetostrictive sensor, for example, both ends of a magnetic wire when a high-frequency current is applied to a magnetic wire having a high magnetic permeability Examples include a magnetic impedance sensor (MI sensor) that measures an external magnetic field using an electromagnetic phenomenon in which impedance between the external magnetic fields changes due to an external magnetic field, and a stress impedance sensor (SI sensor) that uses that an impedance changes due to stress.
[0014]
The rotation-side raceway member is formed of a magnetic material such as high-carbon chromium bearing steel. The fixed-side track member and the rolling element may be made of the same material as the rotating-side track member.However, as for the rolling element, the rolling element does not affect the magnetic field even when approaching or moving away from the magnetostrictive sensor. A non-magnetic material such as a ceramic such as silicon nitride or silicon carbide or a non-magnetic steel material may be used.
[0015]
When the magnetostrictive sensor is a magneto-impedance sensor, an annular magnetized portion facing the sensor may be provided on the rotation-side track member in some cases. Such a magnetized portion may be, for example, magnetized on a rubber magnetic material so that N poles and S poles are alternately and equally spaced, and a magnetic ink row is printed on a film. It may be made to have done.
[0016]
According to the rolling bearing unit with a sensor of the present invention, the gap between the rotating-side track member and the fixed-side track member is detected by the magnetostrictive sensor, and the voltage output from the magnetostrictive sensor is averaged, so that the voltage average and the A proportional relationship with the load applied to the bearing is ensured, whereby the load on the bearing can be accurately obtained from the output of the magnetostrictive sensor. Therefore, when the rolling bearing unit with the sensor is used for a hub unit of an automobile, the force that the rotating-side track member receives from the ground surface, that is, the ground load, is generated from the gap between the rotating-side track member and the fixed-side track member. Accurate detection is possible. The tire contact load thus obtained is used as substitute data for the slip ratio in the ABS control, and is also used in driving force control, braking force control, and the like, and can contribute to improving the accuracy of vehicle control. Further, according to the rolling bearing unit with a sensor of the present invention, the number of rotations, the rotation speed, and the like of the wheel can be detected from the number of repetitions of the change of the gap. Data can be obtained.
[0017]
The fixed-side track member is an outer ring having a mounting portion fixed to the vehicle body, the rotating-side track member is formed of an inner shaft to which the wheel is mounted, and an inner ring externally fitted to the inner shaft, and the magnetostrictive sensor is an outer ring of the inner ring. It may be fixed to the end of the fixed-side track member so as to face the surface.
[0018]
The magnetostrictive sensor may be provided so as to face the outer peripheral surface of the caulked portion for preventing the inner ring from coming off, or may be provided so as to face the outer peripheral surface of the inner shaft. By fixing to the end of the fixed-side track member so as to face, the signal line of the magnetostrictive sensor can be taken out from the end of the fixed-side track member, and the assembly of the sensor-equipped bearing unit can be easily performed. it can. The magnetostrictive sensor can be easily attached to the fixed-side member by embedding it in a resin and integrating the resin with a fixed-side track member or a cover fixed to the same.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
FIG. 1 shows a first embodiment of a rolling bearing unit with a sensor according to the present invention. In the following description, left and right and up and down refer to left and right and up and down in the figure. The left side is inside the vehicle and the right side is outside the vehicle.
[0021]
As shown in FIG. 1, the rolling bearing unit with a sensor includes a hub unit (1) as a rolling bearing, and a sensor device (2) for detecting the rotation and the ground load.
[0022]
The hub unit (1) is arranged in two rows between the fixed-side track member (3) fixed to the vehicle body side, the rotating-side track member (4) to which wheels are attached, and both members (3) and (4). A ball (5), which is a plurality of rolling elements, and a retainer (6) for holding each row of balls (5) are provided.
[0023]
The fixed-side track member (3) is provided near the left end of the cylindrical portion (12) having two rows of outer raceways formed on the inner peripheral surface, and is provided with a bolt on a suspension device (vehicle body). And a flange portion (13) that is attached by a.
[0024]
The rotation-side race member (4) has a large-diameter portion (15) having a first raceway groove (15a) and a small-diameter portion (16) having an outer diameter smaller than the diameter of the first raceway groove (15a). Inner shaft (14), and a small diameter portion (16) of the inner shaft (14), which is fitted to the outer diameter and whose right surface is closely contacted with the large diameter portion (15) left surface of the inner shaft (14). (17). Near the right end of the inner shaft (14), a flange portion (18) to which a plurality of bolts (19) for attaching a wheel are fixed is provided. A track groove (17a) is formed on the right side of the inner ring (17) so as to be parallel to the track groove (15a) of the inner shaft (14), and a shoulder (17b) is formed on the left part of the inner ring (17). ) Is formed. A sealing device (20) is provided between the right end of the fixed-side track member (3) and the inner shaft (14). A cover (21) is placed over the left end of the fixed-side track member (3).
[0025]
The sensor device (2) includes a magnetostrictive sensor (7) attached to the fixed-side track member (3) and a processing unit (10) for processing the output of the magnetostrictive sensor (7) (not shown in FIG. See). The processing means (10) includes, as shown in FIG. 6, a rotation detector (10a) for obtaining the rotation speed of the rotation-side track member (4) from the number of repetitions of the output change of the magnetostriction sensor (7); An averager (10b) for averaging the output of (7) and a load calculator (10c) for obtaining a load applied to the hub unit (1) from the output averaged in the averaging unit (10b). . When the magnetostrictive sensor (7) is a magneto-impedance sensor, the processing means (10) includes a magneto-impedance (MI) element and an oscillation circuit for supplying a high-frequency current to the MI element, and further includes a detection signal amplifying circuit. May be included.
[0026]
In this embodiment, the magnetostrictive sensor (7) is a magneto-impedance sensor, and is embedded in a metal cover (21) with a resin (22). The sensor surface at the tip of the magnetostrictive sensor (7) faces the caulking portion (16a) provided at the end of the small diameter portion (16) of the inner shaft (14) to prevent the inner ring (17) from coming off. . A connector (27) for attaching a harness connecting the processing means (11) provided on the vehicle body side and the sensor device (2) is integrally formed with the resin (22). The connector portion (27) is provided with a signal connector pin (23), and the magnetostrictive sensor (7) and the connector pin (23) are connected via the connector (24) and the lead wire (or only the lead wire). Connected. The detection surface of the magnetostrictive sensor (7) and the outer peripheral surface of the caulked portion (16a) face each other via a radial gap (S). The width of the gap (S) varies depending on the tire contact load, and the magnetostrictive sensor (7) detects the gap between the caulked portion (16a) and the outer peripheral surface of the rotating-side track member (4) as shown in FIG. (S) is output as a voltage value. In the figure, Ti is the rotation period of the rotation-side track member (4), and the gap (S) is a periodic change every rotation.
[0027]
The position at which the magnetostrictive sensor is mounted can be changed as appropriate. As shown in FIG. 2, the magnetostrictive sensor (8) is fixed inside the cover (21), and its sensor surface is a shoulder of the inner ring (17). (17b) You may make it face the outer peripheral surface. The other points in FIG. 2 are the same as in FIG.
[0028]
As shown in FIG. 3, the magnetostrictive sensor (9) is fixed to a substantially central portion in the axial direction of the fixed-side track member (3), and the sensor surface at the tip thereof has a large diameter portion of the inner shaft (14). (15) The outer peripheral surface may be exposed. In the figure, the magnetostrictive sensor (9) is buried in a resin case (25) together with an oscillation circuit. The case (25) includes a connector (27) for attaching a harness connecting the processing means (11) provided on the vehicle body side and the sensor device (2), and the case (25) is a fixed-side track member. A flange portion (25a) for fixing to the outer peripheral surface of (3) is integrally formed. A signal connector pin (23) is provided inside the connector section (27), and the magnetostrictive sensor (9) and the connector pin (23) are connected via a lead wire (24). The case (25) is inserted into a mounting hole (3a) formed in the fixed-side track member (3), and the flange portion (25a) is fixed to the fixed-side track member (3) by bolts (26).
[0029]
Note that the magnetostrictive sensor is not directly supported on the cover (21) or the case (25) by resin as shown in FIG. 1, FIG. 2 or FIG. 3, but is directly attached to the fixed-side track member (3). Is also good.
[0030]
As shown in FIGS. 2 and 3, even when the magnetostrictive sensors (8) and (9) are attached, the outputs of the magnetostrictive sensors (8) and (9) are as shown in FIG.
[0031]
According to the rolling bearing unit with a sensor shown in FIGS. 1 to 3 described above, when the contact load of the tire fluctuates, as shown in FIG. 6, the magnetostrictive sensor (7) ( 8) The air gap between (9) and the rotation-side track member (4) fluctuates. Since the air gap changes periodically as shown in FIG. 4, the rotation detector (10a) of the processing means (10) determines the rotation speed of the rotation-side track member (4) from the number of repetitions of the change of the gap. Can be requested. On the other hand, the amplitude of the gap is averaged in the averaging section (10b) of the processing means (10). The relationship between the averaged voltage of the magnetostrictive sensors (7), (8), and (9) and the grounding load has a linear relationship as shown in FIG. 5, and this linear formula is stored in the memory (11) in advance. By doing so, the grounding load can be determined from the average voltage value of the magnetostrictive sensors (7), (8), and (9) in the grounding load calculation unit (10c) of the processing means (10). The obtained variation amount of the contact load is output to the vehicle control means, and the vehicle is appropriately controlled.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of a rolling bearing unit with a sensor according to the present invention.
FIG. 2 is a longitudinal sectional view showing a second embodiment of a rolling bearing unit with a sensor according to the present invention.
FIG. 3 is a longitudinal sectional view showing a third embodiment of a rolling bearing unit with a sensor according to the present invention.
FIG. 4 is a diagram illustrating an example of an output of a magnetostrictive sensor.
FIG. 5 is a graph showing a relationship between an output of a magnetostrictive sensor and a load.
FIG. 6 is a block diagram of a sensor device of the rolling bearing unit with a sensor according to the first to third embodiments of the present invention;
[Explanation of symbols]
(1) Hub unit (2) Sensor device (3) Fixed track member (4) Rotation track member (7) (8) (9) Magnetostrictive sensor (magnetic impedance sensor)

Claims (2)

A fixed-side race member, a rolling-side bearing member and a rolling bearing having a rolling element disposed between the two members, and a sensor-equipped rolling bearing unit including a sensor device provided on the rolling bearing,
The sensor device has a magnetostrictive sensor provided on the fixed-side track member to detect a gap between the rotary-side track member and processing means for processing the output of the magnetostrictive sensor. A rotation detection unit that calculates the rotation speed of the rotation-side raceway member from the number of repetitions of changes in the sensor output, an averaging unit that averages the output of the magnetostrictive sensor, and a rolling bearing that uses the output averaged in the averaging unit. A rolling bearing unit with a sensor, comprising: a load calculating unit for obtaining a load. The fixed-side track member is an outer ring having a mounting portion fixed to the vehicle body, the rotating-side track member is formed of an inner shaft to which the wheel is mounted, and an inner ring externally fitted to the inner shaft. The sensor-equipped rolling bearing unit according to claim 1, wherein the sensor-equipped rolling bearing unit is fixed to an end of the fixed-side track member so as to face the surface.

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