JP2010002313A - Rotating torque detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating torque detection apparatus which accurately measures the rotating torque of a bearing assembly on which at least an axial load is acting. <P>SOLUTION: The apparatus 1 detects the rotating torque of a rolling bearing assembly 10 having an outer race 11 and an inner race 12 which is arranged inside the outer race 11 coaxially with the outer race 11. The apparatus includes: a load application means 2 for applying an external load including an axial load to the rolling bearing assembly 10; a plurality of strain gauges A to H which are provided on the fixed race side out of the outer race 11 and the inner race 12; and a rotating torque calculation means which calculates the magnitude of the rotating torque of the rolling bearing assembly 10 by performing composite matrix calculations using outputs from the plurality of strain gauges A to H when the rotating race is rotated with a load applied to the rolling bearing assembly 10 by the load application means 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotational torque detection device. More specifically, the present invention relates to a rotational torque detection device that can detect rotational torque with a load applied.

In recent years, from the viewpoint of reducing fuel consumption and reducing CO ₂ emissions in automobiles, there is an increasing demand for lower torque in bearing devices that rotatably support the automobile wheels.
As an index for reducing torque, rotational torque during operation is generally used. Various methods have been proposed for measuring the rotational torque.

  The most general method is a method of measuring the accompanying force of the outer ring when the inner ring (inner shaft) is rotated with various sensors (load cell, strain gauge, torque meter, etc.). By the way, since the load acts on the bearing device during actual vehicle travel, even if it is attempted to measure the rotational torque in a state where the load is applied in such a method, the loss of the load or the support bearing is used when the support bearing is used. Loss due to torque occurs and it is difficult to eliminate the loss.

  Therefore, as a method with relatively little loss, it is conceivable to use a hydrostatic bearing (bearing that supports the shaft by floating it with oil or air) to support the main shaft. It is limited to the radial load, and it is very difficult to accurately detect the rotational torque with a combined load or moment load (simultaneous load of radial load and axial load).

  During actual driving of an automobile, for example, when turning, an axial load may act on the bearing device together with a radial load. To increase the effectiveness, rotation under a moment load where both loads are applied Torque is indispensable data, but no method for obtaining such data has been proposed yet.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a rotational torque detection device capable of accurately measuring the rotational torque of a bearing device on which at least an axial load is applied. .

The rotational torque detection device of the present invention (hereinafter also simply referred to as “detection device”) detects the rotational torque of a rolling bearing device having an outer ring and an inner ring disposed coaxially with the outer ring inside the outer ring. A device to perform
Load loading means for applying an external load including at least an axial load to the rolling bearing device;
A plurality of strain gauges provided on the fixed raceway side of the outer ring and the inner ring,
The rotational torque of the rolling bearing device is calculated by performing a composite matrix operation using outputs from the plurality of strain gauges when the rotating raceway is rotated in a state where a load is applied to the rolling bearing device by the load loading means. And a rotational torque calculating means for calculating the magnitude.

  In the detection device of the present invention, in a state in which an external load including at least an axial load is applied, a composite matrix operation is performed using outputs from a plurality of strain gauges provided on the fixed raceway side, thereby the rolling bearing device. The magnitude of the rotational torque can be calculated. For example, the rotational torque of the automobile bearing device under the moment load condition can be accurately measured. Thus, by obtaining data under the same conditions as in actual vehicle travel, it is possible to effectively reduce the torque of the bearing device.

  The plurality of strain gauges can be provided on the fixed race ring side so that six component forces acting on the rolling bearing device can be calculated. In this case, out of the obtained 6 component forces, only the components necessary for the measurement of the rotational torque can be extracted and used as the measurement values.

  It is preferable to have a temperature correction unit that corrects fluctuations due to temperature changes in outputs from a plurality of strain gauges using a calibration curve obtained in advance. According to this configuration, even if the temperature condition at the time of measurement changes, a more accurate rotational torque value can be obtained by correcting with the calibration curve.

  It is preferable to have a load correction unit that corrects fluctuations due to load changes of outputs from a plurality of strain gauges using a calibration curve obtained in advance. According to this configuration, even if the load fluctuates due to an apparatus installation error, run-out of the rotating raceway, or rotational fluctuation, a more accurate rotational torque value can be obtained by correcting with the calibration curve.

  According to the detection device of the present invention, it is possible to accurately measure the rotational torque of the bearing device on which at least an axial load is applied.

Hereinafter, embodiments of the detection apparatus of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram for explaining a use state of a detection device according to an embodiment of the present invention. This detection device 1 is arranged coaxially with the outer ring 11 and the outer ring 11 on the inner side of the outer ring 11. The rotational torque of the rolling bearing device 10 provided with the inner ring 12 formed and a rolling element 13 composed of a plurality of balls that are rotatably disposed in an annular space between both the wheels 11 and 12 is detected. .

  The detection device 1 is provided in a load loading means 2 for applying an external load to the rolling bearing device 10, a component force detection unit 3 fixed to the outer ring 11 in the rolling bearing device 10, and the component force detection unit 3. The control unit 4 mainly calculates the rotational torque of the rolling bearing device 10 based on output signals from a plurality of strain gauges (details will be described later).

  The load loading means 2 is connected to a first vertical arm 21 fixed to one axial end surface (right end surface in FIG. 1) of the short cylindrical component force detecting unit 3, and an upper end of the first vertical arm 21. A horizontal arm 22, a base portion 23 connected to an end of the horizontal arm 22, which is an end opposite to the side to which the first vertical arm 21 is connected, and stands on the base 23. A second vertical arm 24 provided, and a transmission shaft 25 provided near the upper end of the second vertical arm 24 are provided. The transmission shaft 25 has an output shaft (not shown) of a moving mechanism that can apply loads in the vertical direction, the horizontal direction, and the front-rear direction (the through direction in the drawing) in FIG. It is connected. By moving the moving mechanism, the outer ring 11 fixed to the component force detecting unit 3 is passed through the second vertical arm 24, the horizontal arm 22, the first vertical arm 21 and the component force detecting unit 3. A combined load such as a radial load, an axial load, and a moment load when both loads are simultaneously applied can be appropriately applied.

  A vertical distance r between the horizontal straight line L perpendicular to the axis of the transmission shaft 25 and the axis O of the rolling bearing device 10 is equal to the radius of a general tire mounted on the rolling bearing device 10. As described above, the sizes of the first vertical arm 21 and the second vertical arm 24 are set. Thereby, an external load can be applied to the rolling bearing device 10 in a state close to actual vehicle travel.

  A rotating shaft 5 for transmitting a rotational force to the inner ring 12 is fixed to a flange portion 14 formed on the outer peripheral surface at one axial end of the inner ring 12. The rotating shaft body 5 is fixed to the inner ring 12 by a bolt 15 inserted through a bolt hole formed in the flange portion 14. An output shaft of rotating means such as a motor (not shown) is connected to the rotating shaft body 5 via a speed reduction mechanism as necessary. And the inner ring | wheel 12 can be rotated via a rotating shaft body by rotating a rotation means.

  As shown in FIG. 2, the component force detection unit 3 is mainly configured by a sensor mounting portion 30 formed of a short cylindrical body and flange portions 31 and 32 formed at both axial ends of the sensor mounting portion 30. In order to measure the six component forces acting on the outer ring 11, the outer ring 11 is made of a highly rigid material such as duralumin. As shown in FIG. 7, the “six component force” means that the front-rear horizontal direction of the wheel is the x-axis direction, the left-right horizontal direction (axial direction) of the wheel is the y-axis direction, and the vertical direction of the wheel is the z-axis direction. Assuming a Cartesian coordinate system, the force acting in each axis direction is Fx, Fy, Fz, and the torque around each axis is Mx, My, Mz. That is.

  Of the flange portions 31 and 32, the flange portion 31 on the rolling bearing device 10 side is inserted into a bolt hole formed in the flange portion 16 formed on the outer peripheral surface near one end in the axial direction of the outer ring 11 (see FIG. (Not shown). The flange portion 31 is formed with a recess 33 that can accommodate a part of the outer ring 11 or the inner ring 12 that protrudes toward the flange portion 31 when the rolling bearing device 10 is fixed to the flange portion 31. ing.

  A plurality (eight in this embodiment) of recesses 34 are formed on the outer peripheral surface of the sensor mounting portion 30 at equal intervals along the circumferential direction. The concave portion 34 has a substantially square shape, and the bottom surface portion 34a is thin as shown in FIG. Orthogonal shear strain gauges A to H are respectively affixed to the inner surface side of each bottom surface portion 34a.

The orthogonal shear strain gauges A to H detect the strain of the bottom surface portion 34a when an axial force or a rotational force is applied to the bottom surface portion 34a. As shown in FIG. Resistance elements A1, A2, A3, and A4 (in the case of strain gauge A. In the case of strain gauge B, resistance elements B1 to B4) are provided. These resistance elements A1, A2, A3, and A4 are formed on a flexible substrate, and as shown in FIG. 6, eight bridge circuits B _{1 to} B ₈ are formed.

The orthogonal shear strain gauges A to H are attached in two different forms on the inner surface side of the bottom surface portion 34a adjacent in the circumferential direction. That is, the strain gauge has a central axis C (see FIG. 4) that coincides with the axis of the component force detector 3 (A, C, E, G), and the center axis C _O of the component force detector 3. Those in a state inclined by 45 degrees with respect to the axis (B, D, F, H) are alternately arranged. FIG. 5 shows the arrangement form as a development view.

In the above-described bridge circuits B _{1 to} B ₈ , the strain gauges A, C, E, and G are forces Fx, Fy acting in the axial direction of the above-described orthogonal coordinate system centered on the axis of the component force detector 3, and The torque Mz acting around the axis is detected, and the strain gauges B, D, F, and H detect the force Fz acting in the axial direction and the torque Mx and My acting around the axis.

Output signals from the _eight bridge circuits B _{1 to} B ₈ are AD-converted, and the AD-converted output signals are data-modulated and transmitted to the receiving unit 40 of the control unit 4. The modulated output signal is demodulated by a data demodulation circuit (not shown) included in the processing unit 41 of the control unit 4, and the demodulated output signal is also included in the processing unit 41. A coordinate conversion circuit (not shown), which is a torque calculation means, converts it into six component forces in an orthogonal coordinate system. This conversion can be performed by the matrix operation shown below.

Here, Fx to Mz are force Fx, Fy and Fz acting in the xyz axis direction of the orthogonal coordinate system, and six component forces of torque Mx, My and Mz acting around these axes, and A to H are The output signals of the _eight bridge circuits B _{1 to} B ₈ . K ₁₁ K ₆₈ is a matrix for conversion (conversion matrix).

This transformation matrix applies a known six component force to the component force detector 3, measures the output signals A to H from the bridge circuits B _{1 to} B _{8 at} that time, and obtains the correlation between them. The obtained transformation matrix can be stored in the storage unit 42 of the control unit 4.

  Since it is My that is necessary for the measurement of the rotational torque of the rolling bearing device 10, only the My component is extracted from the obtained 6 component force and used as a measured value. The output signals from the strain gauges A to H vary depending on the temperature of the strain gauges A to H. A calibration curve representing the relationship between the temperature and the output signal is obtained in advance, and the output signal is corrected by the calibration curve. It is preferable to do this. The calibration curve can be stored in the storage unit 42, and the temperature correction can be performed by a temperature correction circuit (temperature correction unit) included in the processing unit 41. By performing the temperature correction, a more accurate rotational torque can be obtained even when the temperature condition during measurement changes.

  In addition, it is conceivable that the load fluctuates due to device installation errors, runout of the rotating raceway, and rotational fluctuations. However, as in the case of temperature correction, a calibration curve representing the relationship between the load and the output signal is obtained in advance. It is preferable to correct the output signal using this calibration curve. The calibration curve can be stored in the storage unit 42, and the load correction can be performed by a load correction circuit (load correction unit) included in the processing unit 41. By performing load correction, a more accurate rotational torque can be obtained even when the load condition during measurement changes.

  In addition, although embodiment mentioned above is a type of rolling bearing in which an inner ring | wheel rotates, the detection apparatus of this invention is applicable also to a type of rolling bearing in which an outer ring | wheel rotates. Further, the present invention can be applied not only to the so-called three-generation hub unit shown in FIG. 1 but also to other wheel bearing devices in general.

  Furthermore, if it is a bearing device used not only in a bearing device that supports a vehicle wheel but also in a device to which a moment load is applied, the specifications such as the shape and size of the load loading means and the component force detection unit described above are applied. The detection device of the present invention can be applied by designing appropriately according to the bearing device.

It is use condition explanatory drawing of one Embodiment of the detection apparatus of this invention. It is side surface explanatory drawing of the detection apparatus shown by FIG. It is the sectional view on the AA line of FIG. It is plane explanatory drawing of the strain gauge used for a component force detection part. It is an expanded view of the sticking position of the strain gauge in the detection apparatus shown by FIG. It is explanatory drawing of the bridge circuit formed with a strain gauge. It is a perspective view which shows the definition of each load with x-axis direction, y-axis direction, and z-axis direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Detection apparatus 2 Load loading means 3 Component force detection part 4 Control unit 10 Rolling bearing apparatus 11 Outer ring 12 Inner ring 21 First vertical arm 22 Horizontal arm 23 Base part 24 Second vertical arm 25 Transmission shaft 30 Sensor attachment part 31 Flange part 32 Flange part 34 Concave part 34a Bottom face part 40 Reception part 41 Processing part 42 Storage part A to H Strain gauge

Claims (4)

A device for detecting the rotational torque of a rolling bearing device having an outer ring and an inner ring disposed coaxially with the outer ring inside the outer ring,
Load loading means for applying an external load including at least an axial load to the rolling bearing device;
A plurality of strain gauges provided on the fixed raceway side of the outer ring and the inner ring,
The rotational torque of the rolling bearing device is calculated by performing a composite matrix operation using outputs from the plurality of strain gauges when the rotating raceway is rotated in a state where a load is applied to the rolling bearing device by the load loading means. A rotational torque detecting device comprising: a rotational torque calculating means for calculating a magnitude.   The rotational torque detection device according to claim 1, wherein the plurality of strain gauges are provided on the fixed race ring side so as to be able to calculate six component forces acting on the rolling bearing device.   The rotational torque detection apparatus according to claim 1, further comprising a temperature correction unit that corrects fluctuations due to temperature changes in outputs from the plurality of strain gauges using a calibration curve obtained in advance.   The rotational torque detection apparatus according to any one of claims 1 to 3, further comprising a load correction unit that corrects fluctuations due to load changes of outputs from the plurality of strain gauges using a calibration curve obtained in advance.

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