JP2008051741A - Sensor-equipped roller bearing device and load measuring system for roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a sensor-equipped roller bearing device. <P>SOLUTION: The sensor-equipped roller bearing device comprises an ultrasonic sensor that enters an ultrasonic wave in the contacting surface between the orbit of the outer ring and a rolling motion object and receives the reflected wave from the contacting surface, and the ultrasonic sensor is connected to a controller 6 that calculates a rolling element load based on the peak value of the analog signal of the reflected wave. The controller 6 includes a peak hold circuit 25 that maintains the peal hold value for a predetermined time, an A/D converting circuit 26 that converts the peak hold signal P2 obtained by the peak hold circuit 25 to a digital signal P3, and a calculating section 28 that calculates the rolling element load based on the digital signal P3 obtained by the A/D converting circuit 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing device with a sensor and a load measuring system for a rolling bearing.

What is conventionally known as a rolling bearing device for supporting a wheel of an automobile or the like includes a cylindrical fixing member fixed to the vehicle body side, a rotating member concentric with the fixing member and to which a wheel is attached, and these fixings Some have two rows of rolling elements that are freely rollable between the member and the rotating member. Various kinds of information are required to control the traveling of the automobile, and one of the information is a load acting on the rolling bearing device. In order to determine the load acting on the rolling bearing device, it has been proposed to provide a sensor in the rolling bearing device and detect the rolling element load from the output signal of this sensor.
An ultrasonic sensor can be used as such a sensor. For example, as shown in Patent Document 1, a contact force (rolling body load) between a rolling element and a track can be detected using the ultrasonic sensor. There is. In Patent Document 1, an ultrasonic wave is incident on a contact surface between a rolling element and a track, a reflected wave from the contact surface is received, a peak value of an analog signal of the reflected wave is detected, and a reference value measured in advance is detected. The contact force is detected by comparing with.

Japanese Patent No. 2581755

Since the frequency used in the ultrasonic sensor is, for example, a high frequency of 5 MHz to 20 MHz, in order to convert the peak value of the analog signal of the reflected wave into a digital signal, a high-speed A having a conversion speed corresponding to the high frequency is used. A / D converter is required. Since such a high-speed A / D converter is expensive, the use of a high-speed A / D converter in a rolling bearing device with a sensor mounted for driving control of an automobile may increase the cost.
Therefore, an object of the present invention is to provide a rolling bearing device with a sensor and a load measuring system for the rolling bearing that can reduce the cost.

The present invention includes an inner ring having a track on the outer periphery, an outer ring having a track on the inner periphery, a rolling element provided so as to freely roll between the tracks of the inner and outer rings, a track of the inner ring or the outer ring, and the rolling element. In a rolling bearing device with a sensor comprising an ultrasonic wave incident on the contact surface and receiving a reflected wave from the contact surface, the sensor device is based on the peak value of the analog signal of the reflected wave Connected to a control device for calculating the rolling element load, the control device maintains the peak value of the analog signal for a predetermined time, and converts the peak hold signal obtained by the peak hold circuit into a digital signal. An A / D conversion circuit that performs the calculation, and a calculation unit that calculates the rolling element load based on the digital signal obtained by the A / D conversion circuit.
According to this configuration, in the process of calculating the rolling element load based on the peak value of the reflected wave obtained by the sensor device, even if the reflected wave is a high frequency, the peak value of the analog signal of the reflected wave is obtained by the peak hold circuit. Therefore, the A / D conversion circuit that converts the peak hold signal obtained by the peak hold circuit into a digital signal can be adapted to low speed. As a result, processing can be performed with an inexpensive low-speed compatible circuit instead of an expensive high-speed compatible A / D converter circuit.

Further, in the rolling bearing device with a sensor, the control device includes a pulse generation circuit that vibrates the vibrator of the sensor device at a predetermined time interval, and from an operation time of the pulse generation circuit to an operation time of the peak hold circuit. It is preferable that a delay circuit capable of variably setting the delay time is provided.
Thereby, the delay time can be set according to the propagation distance of the ultrasonic wave between the sensor device and the contact surface between the track and the rolling element. Thereby, the peak hold circuit can maintain the peak value accurately.

The present invention also relates to a sensor device that receives ultrasonic waves from a contact surface between a raceway of an inner ring or an outer ring constituting a rolling bearing device and a rolling element interposed between the raceways and receives a reflected wave from the contact surface. And a load measuring system for a rolling bearing comprising a control device for calculating a rolling element load based on a peak value of the analog signal of the reflected wave, wherein the control device sets the peak value of the analog signal for a predetermined time. A peak hold circuit to be maintained, an A / D conversion circuit for converting a peak hold signal obtained by the peak hold circuit into a digital signal, and the rolling element based on the digital signal obtained by the A / D conversion circuit And a calculation unit for calculating the load.
According to this configuration, in the process of calculating the rolling element load based on the peak value of the reflected wave obtained by the sensor device, even if the reflected wave is a high frequency, the peak value of the analog signal of the reflected wave is obtained by the peak hold circuit. Therefore, the A / D conversion circuit that converts the peak hold signal obtained by the peak hold circuit into a digital signal can be adapted to low speed. As a result, processing can be performed with an inexpensive low-speed compatible circuit instead of an expensive high-speed compatible A / D converter circuit.

Further, in the load measuring system for the rolling bearing, the control device includes a pulse generation circuit that vibrates the vibrator of the sensor device at a predetermined time interval, and the operation of the peak hold circuit from the operation time of the pulse generation circuit. It is preferable to include a delay circuit capable of variably setting the delay time up to the time point.
Thereby, delay time can be set according to the propagation distance of the ultrasonic wave between the contact surface of a track | orbit and a rolling element, and a sensor apparatus. Thereby, the peak hold circuit can maintain the peak value accurately.

  According to the present invention, the peak value of the analog signal of the reflected wave obtained by the sensor device can be maintained for a predetermined time by the peak hold circuit. Therefore, the A / B for converting the peak hold signal obtained by the peak hold circuit into a digital signal. The D conversion circuit can be made inexpensive and compatible with low speed, and the cost can be reduced.

A preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of a rolling bearing device with a sensor according to the present invention. FIG. 2 is a view of the rolling bearing device with sensor as viewed from the direction of the axis C. This sensor-equipped rolling bearing device (hereinafter also referred to as a rolling bearing device) is capable of rotatably supporting a wheel of a vehicle such as an automobile with respect to a suspension device. When the rolling bearing device is attached to the vehicle body, the axis C direction is the horizontal left / right direction (y-axis direction) which is the vehicle width direction, and the horizontal direction perpendicular to the axis C is the horizontal front / rear direction (x direction). The direction perpendicular to the left-right direction and the front-rear direction is the up-down direction (z direction). That is, in this rolling bearing device, as shown in FIG. 1, the left side is the inside of the vehicle and the right side is the outside of the vehicle.

  This rolling bearing device includes a hub shaft 2 to which a wheel (not shown) is attached, an inner ring member 3 fitted on a part of the inner side of the hub shaft 2 in the left-right direction, and coaxial with the hub shaft 2 and the inner ring member 3. The outer ring 1 is arranged in a shape and is fixed to the vehicle body side, and the balls 5a and 5b as two rows of rolling elements interposed between the hub shaft 2 and the inner ring member 3 and the outer ring 1 so as to roll freely. .

  The hub shaft 2 includes a shaft portion 2b and a flange portion 2a that is located on the outer side in the left-right direction of the shaft portion 2b and attaches a wheel (not shown). The inner ring member 3 is fitted and fixed to the inner side in the left-right direction of the shaft portion 2 b of the hub shaft 2, and rotates integrally with the hub shaft 2. Further, the inner ring member 3 is prevented from coming off by a nut 4 screwed into the inner end portion of the shaft portion 2b. The outer ring 1 is a cylindrical fixing member that is on the radially outer side of the shaft portion 2b of the hub shaft 2 and the inner ring member 3 and is fixed to the vehicle body side. Formed on the inner peripheral surface of the outer ring 1 are an inner first outer ring raceway 12a and an outer second outer ring raceway 12b on which the balls 5a and 5b roll, respectively. On the outer peripheral surface of the outer ring 1, an attachment flange 1a for attachment to a vehicle suspension device (not shown) is formed. A sensor device 10 including a plurality of ultrasonic sensors is attached to the outer ring 1.

  A first inner ring raceway 15a facing the first outer ring raceway 12a is formed on an outer peripheral face of the inner ring member 3, and an outer peripheral face of an outer portion of the shaft portion 2b of the hub shaft 2 is formed on the second outer ring raceway 12b. Opposing second inner ring raceways 15b are formed. As a result, the ball 5a is interposed between the first outer ring raceway 12a and the first inner ring raceway 15a, and the ball 5b is interposed between the second outer ring raceway 12b and the second inner ring raceway 15b. 2, the hub shaft 2 and the inner ring member 3 are rotatable. That is, the inner ring member 3 and the hub shaft 2 become a rotating member (inner ring) having a track on the outer periphery.

  Each ultrasonic sensor of the sensor device 10 includes a state on a contact surface between the first outer ring raceway 12 a on the inner side in the left-right direction of the outer ring 1 and the ball 5 a on the inner side in the left-right direction, and a second outer ring track on the outer side in the left-right direction of the outer ring 1. This is for detecting the contact state on the contact surface between the ball 12b and the outer ball 5b in the left-right direction, and specifically for detecting the rolling element load acting on each contact surface. In each of the inner and outer sides of the outer ring 1, the ultrasonic sensors are provided at four positions at equal intervals in the circumferential direction. Specifically, four ultrasonic sensors 7ti, 7bi, 7fi, 7ri are provided to detect the rolling element load between the balls 5a in the row on the inner side in the left-right direction and the first outer ring raceway 12a. Four ultrasonic sensors 7to, 7bo, 7fo, 7ro are provided to detect the rolling element load between the balls 5b in the outer row in the left-right direction and the second outer ring raceway 12b.

  The ultrasonic sensors 7ti and 7to are provided on the upper part of the outer ring 1, and the detection target position is a contact surface with the balls 5a and 5b at the uppermost position of the first and second outer ring raceways 12a and 12b. The ultrasonic sensors 7bi and 7bo are provided at the lower part of the outer ring 1, and the detection target position is a contact surface with the balls 5a and 5b at the lowest position of the first and second outer ring raceways 12a and 12b. . The ultrasonic sensors 7fi and 7fo are provided at the horizontal front portion of the outer ring 1, and the detection target position is the contact surface with the balls 5a and 5b at the horizontal front position of the first and second outer ring raceways 12a and 12b. It is said. The ultrasonic sensors 7ri and 7ro are provided at the horizontal rear part of the outer ring 1, and the detection target position is a contact surface with the balls 5a and 5b at the horizontal rear position of the first and second outer ring raceways 12a and 12b. Yes.

  The attachment structure of these ultrasonic sensors is the same for all, and as an example, the attachment portion of the ultrasonic sensor 7ti on the upper part of the outer ring 1 will be described with reference to the cross-sectional view of FIG. The ultrasonic sensor 7ti includes a cylindrical case 8 having a male screw portion formed on the outer periphery, and a vibrator (ultrasonic deep touch element) 9 provided in the case 8. A screw hole 37 is formed in the outer ring 1, and the case 8 is attached to the screw hole 37 so that the screwing amount can be adjusted. Further, a buffer material 38 is interposed between the bottom surface of the screw hole 37 and the ultrasonic sensor 7ti (vibrator 9). The ultrasonic sensor 7ti uses the direction perpendicular to the contact surface between the ball 5a and the first outer ring raceway 12a as the incident direction of ultrasonic waves.

  In FIG. 1, each ultrasonic sensor of the sensor device 10 is connected to a control device 6 including, for example, an ECU on the vehicle body side via a signal line. FIG. 4 is a block diagram showing the sensor device 10 and the control device 6 to which the sensor device 10 is connected. The control device 6 can process the reflected wave received by each ultrasonic sensor and calculate the rolling element load based on the peak value of the reflected wave. The control means 6 includes a signal processing unit 11 that processes a signal received by the sensor device 10, and a calculation unit 28 that calculates a rolling element load based on the signal obtained by the signal processing unit 11.

  The signal processing unit 11 includes a booster circuit 21 that boosts a voltage (for example, boosts from 12 V to 100 V) of a battery (not shown) mounted on the vehicle, and a pulse generator circuit 22 that generates a pulse wave using the boosted voltage. is doing. The transducer of each ultrasonic sensor of the sensor device 10 is excited by the pulse wave received from the pulse generation circuit 22, and each ultrasonic sensor enters the ultrasonic wave into the contact surface between the balls 5 a and 5 b and the tracks 12 a and 12 b, The ultrasonic sensor receives an echo (reflected wave) from the contact surface. Further, the signal processing unit 11 includes an amplification circuit 23 that amplifies an analog signal output by receiving an echo from the ultrasonic sensor, a positive / negative inversion circuit 24 that can invert the analog signal amplified by the amplification circuit 23, and positive / negative A peak hold circuit 25 that maintains the peak value (maximum echo amplitude) of the inverted analog signal P1 for a predetermined time, and a peak hold signal P2 that is an analog signal obtained by the peak hold circuit 25 is converted into a digital signal P3. And an A / D conversion circuit 26. Based on the digital signal P3 obtained by the A / D conversion circuit 26, the calculation unit 28 calculates the rolling element load. Further, the signal processing unit 11 includes a delay circuit 27 that gives an operation signal to the peak hold circuit 25.

  A signal processing method and a calculation method in the signal processing unit 11 and the calculation unit 28 will be described. A trigger signal is generated by the function of the signal processing unit 11, and the pulse generation circuit 22 generates a pulse wave based on the trigger signal. The vibrator of each ultrasonic sensor of the sensor device 10 is vibrated at a predetermined time interval by the pulse wave of the pulse generation circuit 22. And each ultrasonic sensor injects an ultrasonic wave into the contact surface of ball 5a, 5b and track 12a, 12b, receives the echo from the contact surface, and outputs an analog signal.

  The amplifier circuit 23 amplifies the analog signal (voltage) from the ultrasonic sensor. When the peak value of the analog signal amplified by the amplifier circuit 23 is obtained as a negative value, the positive / negative inversion circuit 24 inverts it to a positive value. This is because the maximum echo intensity, which is the intensity of the peak value obtained in the later calculation unit 28, is set to a positive value (an absolute value is obtained). When the peak value is obtained as a positive value, the positive / negative inversion circuit 24 may not perform the positive / negative inversion. Then, the peak hold circuit 25 operates, and the peak hold circuit 25 maintains the peak value of the analog signal P1 obtained by the positive / negative inversion circuit 24 for a predetermined time.

  Based on the trigger signal generated by the function of the signal processing unit 11, the delay circuit 27 delays a predetermined time (0.5 μsec to 1.0 μsec) from the operation time of the pulse generation circuit 22, that is, the generation time of the pulse wave. Then, the peak hold circuit 25 is operated. That is, the delay circuit 27 executes the timing at which the peak hold circuit 25 starts to maintain the peak value (peak hold timing) by delaying a predetermined time from the generation of the ultrasonic wave by the ultrasonic sensor. The predetermined time (delay time) is the time from the operation time of the pulse generation circuit 22 to the operation time of the peak hold circuit 25. This delay time is set in the delay circuit 27 from each ultrasonic sensor to the trajectory 12a. , 12b and balls 5a, 5b are variable according to the propagation distance to the contact surface. As a result, the peak hold circuit 25 can operate to accurately maintain the peak value.

  The peak hold circuit 25 includes a composite capacitor (not shown) that maintains the voltage of the peak value of the reflected wave digital signal received by the ultrasonic sensor, and a resistor (not shown) that prevents attenuation of the maintained voltage (hold voltage). Z). 5A and 5B are explanatory diagrams for explaining the function of the peak hold circuit 25. FIG. 5A is a comparative example in which the peak hold circuit 25 is not functioning, and FIG. 5B is an example in which the peak hold circuit 25 is functioned. is there. In FIG. 5, the horizontal axis represents time, and the vertical axis represents echo intensity (voltage). As shown in FIG. 5A, the analog signal output by the echo received by the ultrasonic sensor has a high frequency, and in order to convert this high frequency analog signal into a digital signal, a high-speed A / D is available. A conversion circuit is required. However, according to the peak hold circuit 25 (see FIG. 4), since the peak hold signal P2 can be obtained while maintaining the peak value for a predetermined time, the waveform shown in FIG. The signal P2 can be processed by the low-speed A / D conversion circuit 26. That is, even if the received signal by the echo of the ultrasonic sensor is high frequency, the peak value (peak hold signal P2) of the received signal can be converted into a digital signal by the A / D conversion circuit 26 corresponding to low speed. Accordingly, it is not necessary to use an expensive high-speed A / D conversion circuit, and an inexpensive low-speed A / D conversion circuit 26 can be used, and the cost can be reduced.

Then, the peak hold signal P2 that is an analog signal can be obtained as the maximum echo intensity that is the digital signal P3 by the A / D conversion circuit 26, and using this, the rolling element load and further using this are used. The calculation to obtain the load acting on the rolling bearing device is performed. Note that the booster circuit 21, the pulse generation circuit 22, the amplifier circuit 23, the positive / negative inversion circuit 24, the peak hold circuit 25, the A / D conversion circuit 26, the delay circuit 26, and the ultrasonic sensor are conventionally known. Can be adopted. The calculation unit 28 can be configured by a microcomputer that has a CPU, a memory, and the like and performs calculation processing.
In this embodiment, the signal processing unit 11 and the calculation unit 28 of the control means 6 have been described as ECUs. However, as a modification, a substrate is provided on the outer ring 1 side which is a fixed member of the rolling bearing device. The signal processing unit 11 of the control means 6 may be provided on the substrate, and the arithmetic unit 28 may be provided on the substrate.

As described above, the calculation unit 28 can obtain the maximum echo intensity when each ultrasonic sensor receives the echo, and the calculation unit 28 can obtain the echo ratio shown in the equation (1).
Echo ratio = 100 × (H0−H1) / H0 (1)
However, H0: Maximum echo intensity when the balls 5a and 5b are separated from the ultrasonic sensor by a half pitch (note that one pitch is a circumferential distance between two balls adjacent in the circumferential direction).
H1: Maximum echo intensity when balls 5a and 5b are located directly below the ultrasonic sensor

  When the load acting between the balls 5a and 5b and the tracks 12a and 12b is large, the contact area between the balls 5a and 5b is large and the echo (maximum echo intensity H1) is small, so that a large echo ratio is obtained. And this echo ratio has the relationship shown in FIG. 6, for example with a rolling-element load, and a rolling-element load can be calculated | required from an echo ratio using this relationship. Note that the relationship between the echo ratio and the rolling element load is obtained by measuring in advance. Along with changes in speed and posture of the traveling vehicle, the ground load acting on the wheels fluctuates, and the rolling element load changes according to the ground load. Further, when a plurality of ultrasonic sensors are provided, the degree of influence on the ultrasonic sensors is different for each of the components of the longitudinal load, the lateral load, and the vertical load acting on the wheel. Therefore, the rolling element load when the longitudinal load is applied to the rolling bearing device and the corresponding echo ratio, the rolling element load when the left and right load is applied and the corresponding echo ratio, and the vertical load are applied. By obtaining the rolling element load and the echo ratio corresponding to this, the three-way component force of the load acting on the rolling bearing device can be obtained from the echo ratio obtained by each ultrasonic sensor.

  The calculation unit 28 of the control means 6 includes an equation for the echo ratio, an equation for obtaining a rolling element load at the sensor position from the echo ratio obtained by each ultrasonic sensor, and a load acting on the rolling bearing device from these rolling element loads. Formulas for determining the vertical component, the horizontal component, and the front-rear component of (tire contact load) are stored, and the calculation unit 28 performs a calculation based on each formula.

  The process performed in the calculating part 28 is demonstrated concretely. The relationship between the rolling element load under load and the external force (load F and moment M) acting on the rolling bearing device can be expressed by the following equation (2).

f1 = a + bFy + cFz + dMx
f2 = a + bFy + cFx + dMz
f3 = a + bFy-cFz-dMx
f4 = a + bFy−cFx−dMz (2)
f5 = a−bFy + cFz−dMx
f6 = a−bFy + cFx−dMz
f7 = a−bFy−cFz + dMx
f8 = a−bFy−cFx + dMz
However,
a: Rolling element load due to preload of rolling bearing device b, c, d: Coefficients independent of external force Fx, Fy, Fz: Longitudinal component, lateral component, vertical component of load Mx, Mz: Moment around x axis , Moments around the z axis f1 to f8: rolling element loads obtained from the output of the ultrasonic sensor,
f1: By the ultrasonic sensor 7ti inside the upper part f2: By the ultrasonic sensor 7ri inside the horizontal rear part f3: By the ultrasonic sensor 7bi inside the lower part f4: By the ultrasonic sensor 7fi inside the horizontal front part f5: By the upper part By the outer ultrasonic sensor 7to f6: By the horizontal rear outer ultrasonic sensor 7ro f7: By the lower outer ultrasonic sensor 7bo f8: By the horizontal front outer ultrasonic sensor 7fo And this formula (2 ) Can be used to determine the external force acting on the rolling bearing device from the rolling element load.

On the other hand, the following formulas (3) and (4) are established for the wheels: Mx = r × Fy + e × Fz (3)
Where r: wheel rolling radius
e: Deviation between the action point of Fz in the left-right (y-axis) direction and the center of the rolling bearing device My = r × Fx (4)
However, My: moment about the y-axis

  The left-right direction component Fy and the up-down direction component Fz can be obtained by using f1 and f3 of the formula (2) and the formula (3). That is, by setting f1 + f3, Fy is obtained, and by setting f1-f3, a linear expression including Fz and Mx is obtained, and Fy in Expression (3) is obtained. Using this, a linear expression including Fz and Mx in the expression (3) is used, and Fz and Mx are obtained by combining these two linear expressions.

  In this way, the two ultrasonic sensors 7ti and 7bi can determine the vertical component Fz and the horizontal component Fy of the load acting on the wheel, and incidentally the moment Mx about the x axis. The up-down direction component Fz and the left-right direction component Fy of the load acting on the wheels are important elements for knowing the cornering state of the vehicle, and these are obtained by a small number of ultrasonic sensors (two ultrasonic sensors 7ti, 7bi). By calculating | requiring, the rolling bearing apparatus with a sensor excellent in cost performance can be obtained. In the above description, f1 and f3 are used. However, a combination other than this combination can be used (for example, f1 and f5).

  Further, Mx can be obtained by setting f1 + f7, linear expressions of Fy and Fz can be obtained by setting f1−f7, and Mx, Fy, and Fz can be obtained by combining these with Expression (4). Then, since the linear expressions of Fy and Fx are obtained by setting to f2−f8, the remaining Fx can be obtained by substituting the already obtained Fy into this linear expression. If Fx is obtained, Mx is also obtained. Further, Mz can be obtained by setting f2 + f8.

  Thus, the four ultrasonic sensors 7ti, 7ri, 7bo, 7fo can obtain all six component forces acting on the wheels, and a sensor-equipped rolling bearing device with excellent cost performance can be obtained. In the above description, f1, f2, f7, and f8 are used. However, other combinations can be used (for example, f1, f2, f3, and f6).

  In the case of the above formulas (2) to (4), when obtaining the relationship between the external force acting on the rolling bearing device and the echo ratio, the correlation between the rolling element load and the external force and the correlation between the rolling element load and the echo ratio. Is obtained by a two-stage calculation. Therefore, equation (5) will be described as a method for directly obtaining the relationship between the echo ratio and the external force acting on the rolling bearing device. According to this, the error can be reduced.

j1 = k + lFy + mFz + nMx
j2 = k + lFy + mFx + nMz
j3 = k + lFy-mFz-nMx
j4 = k + lFy-mFx-nMz (5)
j5 = k−1Fy + mFz−nMx
j6 = k−1Fy + mFx−nMz
j7 = k−1Fy−mFz + nMx
j8 = k-1Fy-mFx + nMz
However,
k: Echo ratio due to preload of rolling bearing device l, m, n: Coefficients independent of external force Fx, Fy, Fz: Longitudinal component, lateral component, vertical component of load Mx, My, Mz: x axis, y Moment about the axis and z axis j1 to j8: Echo ratio obtained from the output of the ultrasonic sensor j1: Based on the output of the upper inner sensor 7ti j2: Based on the output of the rear inner sensor 7ri j3: Lower inner Based on the output of the sensor 7bi j4: Based on the output of the sensor 7fi inside the front part j5: Based on the output of the sensor 7to outside the upper part j6: Based on the output of the sensor 7ro outside the rear part j7: Based on the output of the sensor 7bo outside the bottom part J8: Based on the output of the front outside sensor 7fo

A 6 component force calculation method using the equation (5) will be described. When obtaining 6 component forces, in addition to the above relationship, the following equations (6) and (7) are used for the wheels.
Mx = r × Fy + e × Fz (6)
My = r × Fx (7)
Where r: wheel rolling radius
e: Deviation between the action point of Fz and the center of the rolling bearing device in the left-right (y-axis) direction

Using these equations (6) and (7) and using four of the equations (5) of j1 to j8, six component forces can be obtained. As an example, a case where j1, j2, j3, and j6 are used will be described.
(Step 1) The left-right direction component Fy is obtained. Two expressions j1 and j3 are selected from the expression (5), and Fz and Mx are eliminated by addition or subtraction (addition in this case) of these expressions. Thereby, Fy = (j1 + j3-2k) / 2 is obtained.
(Step 2) The vertical direction component Fz is obtained. From the linear expression of Fz and Mx obtained by eliminating Fy from the two expressions of Expression (5), and the linear expression of Fz and Mx obtained by substituting Fy into Expression (6), Fz Ask for. Thereby, Fz = (1-nr) j1- (1 + nr) j3 + 2knr / 2 · l · (m + ne) is obtained.

(Step 3) A moment Mx about the x axis is obtained. Mx is obtained using Fy obtained in step 1 and Fz obtained in step 2. Thereby, Mx = rFy + eFz is obtained.
(Step 4) The front-rear direction component Fx is obtained. Two expressions j2 and j6 are selected from the expression (5), and Fx and Mz are deleted by adding or subtracting (addition in this case). Thereby, Fx = j2 + j6-2k / 2m is obtained.

(Step 5) The moment My about the y-axis is obtained. Using Fx obtained in step 4, My is obtained. Thereby, My = rFx is obtained.
(Step 6) A moment Mz about the z axis is obtained. Two equations j1 and j3 are selected from equation (5), and Fy is eliminated by addition or subtraction (here, subtraction) to obtain a linear expression of Fx and Mz, and two equations from equation (5) are obtained. j2 and j6 are selected, and by adding or subtracting (subtraction in this case), Fy is eliminated and a linear expression of Fx and Mz is obtained. Mz is obtained by eliminating Fx from the two linear expressions. Thereby, Mz = −j1 + j2−j3−j6 + 2k / 2n is obtained.
As described above, all of the six component forces acting on the wheels can be obtained by the four ultrasonic sensors 7ti, 7ri, 7bi, 7ro.

  Moreover, in each embodiment of the rolling bearing device of the present invention, as shown in FIGS. 1 and 2, ultrasonic sensors are arranged at four locations in the circumferential direction of the outer ring 2 which is a fixing member. The positions to be detected by the ultrasonic sensors are contact surfaces with the balls 5a and 5b at the upper position, the lower position, the horizontal front position, and the horizontal rear position, respectively, of the tracks 12a and 12b. Thereby, based on each received signal of an ultrasonic sensor, the 3 component force (front-rear direction load, left-right direction load, up-down direction load) of the load which acts on a rolling bearing apparatus can be calculated | required. Further, the component force (direction component) to be obtained out of the load acting on the rolling bearing device is likely to cause an error due to the influence of the component force in the other direction. It can be obtained with high accuracy, and further, the moment about each axis can be obtained. Note that the sensor-equipped rolling bearing device of the present invention is not limited to the above-described embodiment, and the rolling bearing device may have another form.

It is sectional drawing which shows one Embodiment of the rolling bearing apparatus with a sensor of this invention. It is the figure which looked at the rolling bearing device with a sensor of Drawing 1 from the direction of an axis. It is sectional drawing explaining the attaching part of the ultrasonic sensor in the upper part of an outer ring | wheel. It is a block diagram of a sensor apparatus and a control means. It is explanatory drawing explaining the function of a peak hold circuit, (a) is a comparative example which does not function a peak hold circuit, (b) is the Example which functioned the peak hold circuit. It is a graph which shows a relationship between an echo ratio and a rolling element load.

Explanation of symbols

1 Outer ring 2 Hub axle (inner ring)
3 Inner ring member (inner ring)
5a ball (rolling element)
5b ball (rolling element)
6 Control means 7 Ultrasonic sensor 10 Sensor device 11 Signal processing unit 12a First outer ring raceway 12b Second outer ring raceway 15a First inner ring raceway 15b Second inner ring raceway 25 Peak hold circuit 28 Calculation unit C axis

Claims (3)

An inner ring having a track on the outer periphery, an outer ring having a track on the inner periphery, a rolling element provided so as to be able to roll between the tracks of the inner and outer rings, and a contact surface between the track of the inner ring or the outer ring and the rolling element. In a rolling bearing device with a sensor comprising a sensor device that receives ultrasonic waves and receives reflected waves from the contact surface,
The sensor device is connected to a control device that calculates a rolling element load based on a peak value of the analog signal of the reflected wave,
The control device includes a peak hold circuit that maintains a peak value of the analog signal for a predetermined time, an A / D conversion circuit that converts a peak hold signal obtained by the peak hold circuit into a digital signal, and the A / D A rolling bearing device with a sensor, comprising: a calculation unit that calculates the rolling element load based on the digital signal obtained by the conversion circuit.   The control device may variably set a pulse generation circuit that vibrates the vibrator of the sensor device at a predetermined time interval, and a delay time from an operation time of the pulse generation circuit to an operation time of the peak hold circuit. The rolling bearing device with a sensor according to claim 1, further comprising a delay circuit that can be used. A sensor device that receives ultrasonic waves on the contact surfaces between the races of the inner ring or outer ring constituting the rolling bearing device and the rolling elements interposed between these race tracks and receives the reflected waves from the contact surfaces, and an analog of the reflected waves In a load measuring system for rolling bearings, comprising a control device for calculating the rolling element load based on the peak value of the signal,
The control device includes a peak hold circuit that maintains a peak value of the analog signal for a predetermined time, an A / D conversion circuit that converts a peak hold signal obtained by the peak hold circuit into a digital signal, and the A / D A calculation unit that calculates the rolling element load based on the digital signal obtained by the conversion circuit, a pulse generation circuit that vibrates the vibrator of the sensor device at a predetermined time interval, and an operation time point of the pulse generation circuit A load measuring system for a rolling bearing, comprising: a delay circuit capable of variably setting a delay time until the peak hold circuit is activated.

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