JP4887754B2 - Rolling bearing device with sensor - Google Patents

Description

  The present invention relates to a rolling bearing device with a sensor in which a rolling bearing and a sensor device for detecting various information thereof are integrated.

In automobiles, various information is necessary to perform the control. Therefore, a fixed-side track member fixed to the vehicle body side, a rotation-side track member to which wheels are attached, and two members disposed between the two members. It has been proposed to provide a sensor device in a hub unit (rolling bearing) having rows of rolling elements. For example, Patent Document 1 discloses that the ground load is accurately obtained by providing a magnetic impedance sensor on the fixed-side track member and providing an annular magnetized portion facing the sensor on the rotation-side track member. Has been.
JP 2004-45370 A

  According to the rolling bearing device with a sensor of the above-mentioned patent document 1, since the detection by the magnetic impedance sensor is affected by the material, shape, processing accuracy, etc. of the detected part, there are restrictions on the selection of the material of the rolling bearing, There was a problem that processing of a magnetic part and addition of another member were needed for a detected part.

  An object of the present invention is to provide a sensor-equipped rolling bearing device in which there are few restrictions on the material selection of the detected part and no additional processing is required for the detected part.

The sensor device according to the present invention is a rolling bearing device with a sensor comprising a rolling bearing having a stationary race member, a rotating race member and rolling elements, and a sensor device, wherein the rolling bearing is a hub unit for an automobile, The sensor device is provided in at least two places with a predetermined interval in the circumferential direction of the fixed-side track member, and detects the rolling element load as an echo ratio, and acts on the rolling bearing from the output of each ultrasonic sensor. Processing means for determining at least the vertical and horizontal components of the three directional components of the load, and the following formula (1) is provided in the processing means as an expression for determining the load acting on the hub unit from the rolling element load. It is characterized by being.
f1 = a + bFy + cFz + dMx
f2 = a + bFy + cFx + dMz
f3 = a + bFy-cFz-dMx
f4 = a + bFy−cFx−dMz Equation (1)
f5 = a−bFy + cFz−dMx
f6 = a−bFy + cFx−dMz
f7 = a−bFy−cFz + dMx
f8 = a−bFy−cFx + dMz
Where a: rolling element load due to preload of the hub unit, b, c, d: coefficients not depending on external force, Fx, Fy, Fz: front-rear (x-axis) direction component, left-right (y-axis) direction component, and upper and lower (Z-axis) direction component, Mx, Mz: x-axis, moment about z-axis, f1-f8: rolling element load at each sensor position.

  The ultrasonic sensor has, for example, a cylindrical case having a threaded portion formed on the outer periphery and a vibrator disposed in the case, and has a bottomed female threaded portion provided on the fixed-side track member. It is preferable that a predetermined preload is set at the tip of the case by screwing the male thread portion of the case. The intensity of the reflected echo obtained by the ultrasonic sensor varies depending on the sensor mounting method, mounting surface roughness, contact medium difference, and sensor pressing force. The echo intensity at the location can be set to a predetermined value, thereby improving the accuracy of load detection. The ultrasonic sensor can be attached by various methods capable of setting the echo intensity to a predetermined value. For example, the ultrasonic sensor has a cylindrical case and a case having a flange portion for attaching to the fixed-side track member. The case has a vibrator arranged inside, and a bolt inserted through a bolt insertion hole provided in a flange portion is screwed into a bottomed female screw portion provided in a fixed race member. A predetermined preload may be set at the tip.

  The nut of the case of the ultrasonic sensor case is screwed to the base end of the screw part of the case, preventing water from entering the female thread part between the nut and the fixed raceway member. More preferably, an O-ring is interposed. If it does in this way, even if it installs in the place where a vibration is large and the water from the outside tends to enter like a hub unit for cars, the performance can be maintained.

  When the rolling bearing is an automobile hub unit, the following formula (1) is preferably provided in the processing means as an expression for obtaining a load acting on the rolling bearing from the rolling element load.

f1 = a + bFy + cFz + dMx
f2 = a + bFy + cFx + dMz
f3 = a + bFy-cFz-dMx
f4 = a + bFy−cFx−dMz Equation (1)
f5 = a−bFy + cFz−dMx
f6 = a−bFy + cFx−dMz
f7 = a−bFy−cFz + dMx
f8 = a−bFy−cFx + dMz
Where a: rolling element load due to preload of the hub unit, b, c, d: coefficients not depending on external force, Fx, Fy, Fz: front-rear (x-axis) direction component, left-right (y-axis) direction component, and upper and lower (Z-axis) direction component, Mx, Mz: x-axis, moment about z-axis, f1-f8: rolling element load at each sensor.

  The relationship between the rolling element load and the external force acting on the hub unit can be calculated based on the bearing calculation theory, and the relationship between the rolling element load and the external force acting on the hub unit has a substantially linear relationship. The above equation (1) is obtained by performing multiple analysis based on the theoretical calculation result.

  In addition, what combined the component (3-direction component force) of each axial direction of a load and the moment (3-direction moment) around each axis is called "6 component force" below.

  By utilizing the relationship of the above formula (1), the 6 component force of the load can be obtained with high accuracy. Regarding the number of sensors and the configuration of the processing means, various measures can be taken in consideration of the cost increase accompanying the increase in the number of sensors. In particular, when the rolling bearing device with a sensor according to the present invention is applied to a hub unit for an automobile, the following processing means can be configured by adding a formula that holds for the wheel.

  For example, the number of sensors is two, and the processing means obtains the vertical component and the horizontal component of the load acting on the rolling bearing from two appropriate equations of the equation (1) and the following equation (2). It is supposed to be.

Mx = r × Fy + e × Fz (2)
However, r: Wheel rolling radius, e: Deviation between the action point of Fz and the hub unit center in the y-axis direction.

  Further, the number of sensors is four, and the processing means obtains six component forces acting on the rolling bearing from the appropriate four expressions of the expression (1), the expression (2), and the following expression (3). Is done.

My = r × Fx ……… Formula (3)
However, My: moment about the y-axis.

  In addition, since said Formula (1) is a formula which shows the relationship between rolling-element load and the external force which acts on a hub unit, by calculating | requiring the relationship between rolling-element load and the echo ratio obtained with an ultrasonic sensor, The relationship between the external force acting on the hub unit and the echo ratio is obtained. That is, it is necessary to obtain two correlations, and the error may increase. Therefore, instead of this, the load acting on the rolling bearing is calculated using the echo ratio measured by the ultrasonic sensor, and the following formulas (4) to (6) are given as processing formulas for the processing means. It may be provided.

j1 = k + lFy + mFz + nMx
j2 = k + lFy + mFx + nMz
j3 = k + lFy-mFz-nMx
j4 = k + lFy−mFx−nMz Equation (4)
j5 = k−1Fy + mFz−nMx
j6 = k−1Fy + mFx−nMz
j7 = k−1Fy−mFz + nMx
j8 = k-1Fy-mFx + nMz
Mx = r × Fy + e × Fz (5)
My = r × Fx Equation (6)
Where k: echo ratio due to hub unit preload, l, m, n: coefficients independent of external force, Fx, Fy, Fz: longitudinal (x-axis) direction component, lateral (y-axis) direction component and vertical ( z-axis) direction component, Mx, My, Mz: x-axis, y-axis, moment about z-axis, j1 to j8: echo ratio at each sensor position, r: wheel rolling radius, e: Fz in y-axis direction Deviation between the operating point and the hub unit center.

  According to the sensor rolling bearing device of the present invention, there are few restrictions on the material selection of the detected part, and no additional processing on the detected part is required.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 3 show an embodiment of a rolling bearing device with a sensor according to the present invention. In the following description, the left and right refer to the left and right in FIG. Note that the left is inside the vehicle and the right is outside the vehicle.

  The sensor-equipped rolling bearing device is used as a sensor-equipped hub unit for an automobile, and includes an automobile hub unit (1) and a sensor device (2) that detects a ground contact load of a tire.

  The hub unit (1) is arranged in two rows between the fixed side track member (3) fixed to the vehicle body side, the rotary side track member (4) to which the wheel is attached, and both members (3) and (4). A ball (5), which is a plurality of rolling elements, and a cage (6) for holding each row of balls (5) are provided.

  The fixed-side raceway member (3) has a bearing outer ring (fixed ring) function, and includes a cylindrical portion (12) in which two rows of outer ring raceways are formed on the inner peripheral surface, and a cylindrical portion (12 ) And a flange portion (13) attached to the suspension device (vehicle body side portion) with a bolt.

  The rotation side raceway 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). The inner ring (14), and the inner ring (14), the inner ring (14), which has a small diameter part (16) and is fitted to the outer diameter, and the right side is in close contact with the left side of the large diameter part (15) of the inner axis (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 is fixed is provided. A raceway groove (17a) is formed in the right part of the inner ring (17) so as to be parallel to the raceway groove (15a) of the inner shaft (14), and a shoulder part (17b ) Is formed. A sealing device (20) is provided between the right end portion of the fixed-side track member (3) and the inner shaft (14). A male screw is provided at the left end of the small diameter portion (16) of the inner shaft (14), and the inner ring (17) is connected to the inner shaft (14) by a nut (21) screwed to the male screw. It is fixed to. A cover (22) is covered with the left end portion of the fixed race member (3).

  The sensor device (2) is an ultrasonic sensor (Sti) (Sbi) that detects the force (hereinafter referred to as “rolling element load”) acting between the fixed side raceway member (3) and the inner row of balls (5). ) And the ultrasonic sensors (Sto) (Sbo) that detect the rolling element load of the ball (5) in the outer row, and the output of these ultrasonic sensors (Sti) (Sto) (Sbi) (Sbo) And processing means (see FIG. 7).

  The ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo) are located at the top of the fixed-side track member (3) shown in FIG. 1 = the top (Sti) (Sto) (the position indicated by A in FIG. 2). ) And the lowermost portion of the fixed race member (3) = bottom (Sbi) (Sbo) (position indicated by D in FIG. 2) (Position indicated by B in FIG. 2) and the front side of the upper and lower intermediate portions of the fixed-side track member (3) = front part (position indicated by C in FIG. 2). However, the number and arrangement of the ultrasonic sensors are not limited to this.

  The ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo) obtain the reflected echo as shown in FIG. 4 by receiving the reflected wave of the ultrasonic wave output from the transducer at the receiving unit. The output is obtained as an echo ratio shown below.

Echo ratio = 100 × (H0−H1) / H0
H0: Echo intensity when the rolling element is separated from the ultrasonic sensor by a half pitch H1: Echo intensity when the rolling element is located directly below the ultrasonic sensor This echo ratio has the relationship shown in FIG. By using this, the rolling element load can be obtained from the echo ratio. If the load acting on the ball (5) is large, the contact area becomes large and the reflected wave becomes small. Therefore, when the rolling element load is large, a large echo ratio is output.

  The ground load applied to the tire varies with changes in speed and posture of the traveling vehicle, and the rolling element load varies according to the tire ground load variation. When multiple sensors are installed, the degree of influence on the sensor differs depending on the components of the longitudinal load, left and right load, and vertical load acting on the tire. By obtaining the corresponding echo ratio, rolling element load when left and right load is applied and the corresponding echo ratio, and rolling element load when vertical load is applied and the corresponding echo ratio, ultrasonic waves are obtained. From the echo ratio obtained by the sensors (Sti), (Sto), (Sbi), and (Sbo), the three-way component force of the tire contact load can be obtained.

  The processing means of the sensor device (2) includes an equation for an echo ratio, an equation for obtaining a rolling element load at the sensor position from the echo ratio obtained from each ultrasonic sensor (Sti) (Sto) (Sbi) (Sbo), Formulas for obtaining the vertical component, the front-rear direction component, and the left-right component of the tire ground contact load from these rolling element loads are stored.

  When sensors are installed at multiple locations and each component of the ground load is obtained separately, errors due to the effects of other components are likely to occur. (Sti) (Sto) (Sbi) (Sbo) is installed in a total of 8 locations on the inside, outside of the top, bottom, front and rear of the fixed-side track member (3). Can be obtained with high accuracy, and the moment about the longitudinal axis and the moment about the vertical axis can also be obtained.

  The ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo) are shown in FIG. 3 (shown inside the top portion), and a cylindrical case (51a) having a threaded portion (51a) formed on the outer periphery. ) And a vibrator (52) disposed in the case (51), facing the contact surface between the ball (5) and the raceway groove (3a) of the stationary raceway member (3) from a direction perpendicular to the contact surface. Has been. The fixed-side raceway member (3) is provided with a bottomed female screw portion (3b), and the screwing amount of the male screw portion (51a) of the case (51) can be adjusted. A rubber cushion sheet (53) for protecting the tip of the ultrasonic sensor (Sti) is interposed between the tip of the case (51) and the bottom of the female thread (3b). A nut (54) for preventing rotation of the case (51) is screwed onto the proximal end portion of the male thread portion (51a) of the case (51). An O-ring (55) that prevents water from entering the female thread portion (3b) is interposed between the nut (54) and the fixed race member (3).

  The intensity (echo amplitude) of the echo obtained by the ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo) varies greatly depending on the sensor mounting method, the roughness of the mounting surface, and the contact medium. FIG. 5 shows the relationship between the mounting surface roughness and the echo amplitude, and it can be seen from this graph that the echo amplitude decreases as the mounting surface becomes rough. In addition, the intensity of the echo varies depending on the pressing force of the sensor. For this reason, the relationship between the echo ratio and the rolling element load varies for each of the ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo), and there is a possibility that the accuracy of the tire contact load detection is lowered.

  According to the ultrasonic sensor (Sti) shown in FIG. 3, it is possible to change the pressing force of the sensor (Sti) by changing the screwing amount of the male thread portion (31a) of the case (31). Therefore, the echo intensity H0 can be changed and set to a predetermined value by finely adjusting the screwing amount while viewing the echo waveform shown in FIG. Thereby, the dispersion | variation in the relationship between the echo ratio and rolling element load for every ultrasonic sensor (Sti) (Sto) (Sbi) (Sbo) is suppressed, and the precision of a tire ground contact load detection can be improved.

  In the above description, the total number of sensors is eight, but the number of sensors is not limited to this. If the number of sensors is large, the cost increases accordingly. Therefore, it is necessary to consider obtaining data as useful as possible by reducing the number of sensors. Hereinafter, a load detection method using a small number of sensors (when obtaining load components in two directions with two sensors and obtaining load components in three directions with four sensors) is shown (see FIG. 7).

  First, the relationship between the rolling element load under load calculated based on the bearing calculation theory and the external force (load and moment) acting on the hub unit can be expressed by the following equation.

f1 = a + bFy + cFz + dMx
f2 = a + bFy + cFx + dMz
f3 = a + bFy-cFz-dMx
f4 = a + bFy−cFx−dMz Equation (1)
f5 = a−bFy + cFz−dMx
f6 = a−bFy + cFx−dMz
f7 = a−bFy−cFz + dMx
f8 = a−bFy−cFx + dMz
Where a: rolling element load due to preload of the hub unit, b, c, d: coefficients not depending on external force, Fx, Fy, Fz: front-rear (x-axis) direction component, left-right (y-axis) direction component, and upper and lower (Z-axis) direction component, Mx, Mz: moments around the x-axis and z-axis, f1 to f8: rolling element loads obtained from the outputs of the ultrasonic sensors (Sti) (Sto) (Sbi) (Sbo) f1 is based on the output of the sensor (Sti) inside the top part, f2 is based on the output of the sensor inside the rear part, f3 is based on the output of the sensor (Sbi) inside the bottom part, and f4 is a sensor inside the front part. F5 is due to the output of the sensor outside the top (Sto), f6 is due to the output of the sensor outside the rear, f7 is due to the output of the sensor (Sbo) outside the bottom, and f8 is By the output of the sensor outside the front.

  The use of the relationship of formula (1) has not been known at all, and the external force acting on the rolling bearing can be easily obtained from the rolling element load by using this relationship.

  On the other hand, in the case of a wheel (tire), the following equation is established.

Mx = r × Fy + e × Fz (2)
However, r: Wheel rolling radius, e: Deviation between the action point of Fz and the hub unit center in the y-axis direction.

My = r × Fx ……… Formula (3)
However, My: moment about the y-axis.

  As can be seen from the above equation, the left-right direction component Fy and the up-down direction component Fz can be obtained by using f1 and f3 of the equation (1) and the equation (2). 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 (2) is obtained. As a result, Equation (2) also becomes a linear equation including Fz and Mx, and Fz and Mx are obtained by combining these two linear equations.

  Thus, the two sensors can determine the vertical component and the horizontal component of the load acting on the wheel (and the moment about the x axis incidentally). The vertical and horizontal components of the load acting on the wheel are important factors in knowing the cornering state of the vehicle. By obtaining these with a small number of sensors (two sensors in total), cost performance is excellent. A rolling bearing device with a sensor can be obtained.

  In the above description, f1 and f3 are used. However, it is also possible to use a combination other than this combination (for example, f1 and f5).

  Further, Mx can be obtained by setting f1 + f7, and 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 (3). it can. Since the primary expressions of Fy and Fx are obtained by setting to f2-f8, the remaining Fx can be obtained by substituting Fy that has already been obtained for this primary expression. If Fx is obtained, Mx is also obtained. Further, Mz can be obtained by setting f2 + f8.

In this way, all six component forces acting on the wheels can be obtained with four sensors, 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, it is also possible to use a combination other than this combination (for example, f1, f2, f3, and f6).

  The equations (1) to (3) above show the correlation between the rolling element load and the external force and the correlation between the rolling element load and the echo ratio when determining the relationship between the external force acting on the hub unit and the echo ratio. Since it is used and obtained in two stages, there is a risk that the error will increase.

  Therefore, it is preferable to directly obtain the relationship between the echo ratio and the external force acting on the hub unit. This relationship is such that k is an echo ratio due to the preload of the hub unit, l, m, and n are coefficients that do not depend on external force, and Fx, Fy, and Fz are the front and rear (x-axis) direction components and left and right (y Axis) direction component and vertical (z-axis) direction component, Mx, My, and Mz are moments around the x-axis, y-axis, and z-axis, respectively, and j1 to j8 are ultrasonic sensors (Sti) (Sto) The echo ratio obtained from the output of (Sbi) (Sbo) (j1 is due to the output of the sensor (Sti) inside the top, j2 is due to the output of the sensor inside the rear, and j3 is the sensor inside the bottom (Sbi) ), J4 is due to the output of the sensor inside the front part, j5 is due to the output of the sensor (Sto) outside the top part, j6 is due to the output of the sensor outside the rear part, and j7 is the bottom part. According to the output of the outer sensor (Sbo), j8 is the front outer sensor. The output is as follows.

j1 = k + lFy + mFz + nMx
j2 = k + lFy + mFx + nMz
j3 = k + lFy-mFz-nMx
j4 = k + lFy−mFx−nMz Equation (4)
j5 = k−1Fy + mFz−nMx
j6 = k−1Fy + mFx−nMz
j7 = k−1Fy−mFz + nMx
j8 = k-1Fy-mFx + nMz
A method of calculating the 6 component force using the above formula will be described below. In obtaining six component forces, in addition to the above relationship, the fact that the following equation is established in the case of a wheel (tire) is used.

Mx = r × Fy + e × Fz (5)
My = r × Fx Equation (6)
Here, r: wheel rolling radius, e: deviation of the Fz operating point and hub unit center in the y-axis direction By using these two equations, using four equations j1 to j8, 6 component force can be calculated. As an example, when j1, j2, j3 and j6 are used, six component forces are obtained as follows.

  Step 1: A left-right direction component Fy is obtained. Two appropriate expressions (here, j1 and j3) are selected from the expression (4), and Fz and Mx are eliminated by addition or subtraction (here, addition) of the two expressions. Fy is obtained by the following equation.

Fy = (j1 + j3-2k) / 2l
Step 2: The vertical direction component Fz is obtained. From the linear expression of Fz and Mx obtained by eliminating Fy from two expressions of Expression (4), and the linear expression of Fz and Mx obtained by substituting Fy into Expression (5) , Fz is obtained. Fz is obtained by the following equation.

Fz = {(l-nr) j1- (l + nr) j3 + 2knr} / 2l (m + ne)
Step 3: A moment around the x axis (moment around the traveling direction) Mx is obtained. Mx is obtained using Fy obtained in Step 1 and Fz obtained in Step 2. Mx is obtained by the following equation.

Mx = rFy + eFz
Step 4: The front-rear direction component Fx is obtained. Two appropriate expressions (here, j2 and j6) are selected from the expression (4), and Fx and Mz are eliminated by addition or subtraction (here, addition) of the two expressions. Fx is obtained by the following equation.

Fx = {j2 + j6-2k} / 2m
Step 5: A moment (wheel rotation torque) My about the y-axis is obtained. My is determined using Fx obtained in step 4. My is obtained by the following equation.

My = rFx
Step 6: A moment Mz about the z-axis (vertical direction) is obtained. Two appropriate expressions (here, j1 and j3) are selected from the expression (4), Fy is eliminated by addition or subtraction (here, subtraction) of the two expressions, and a linear expression of Fx and Mz is obtained. In addition, two appropriate expressions (here, j2 and j6) are selected from the expression (4), Fy is eliminated by adding or subtracting (here, subtraction) of the two expressions, and 1 of Fx and Mz is obtained. The following equation is obtained. Mz is obtained by erasing Fx from two linear equations. Mz is obtained by the following equation.

Mz = {− j1 + j2−j3−j6 + 2k} / 2n
In addition, the attachment structure of the ultrasonic sensor shown in FIG. 3 is an example, and is not limited thereto, and may be as shown in FIG. In FIG. 8, the ultrasonic sensor (Sti) includes a cylindrical case (61) provided with a flange portion (61a) to be attached to the fixed-side track member (3), and a vibration disposed in the case (61). A plurality of internal thread portions (3c) are provided on the portion to which the flange portion (61a) of the stationary race member (3) is applied, and the flange portion (61a) The bolt (63) inserted from the provided bolt insertion hole is screwed into the female thread (3c), so that a predetermined preload is set at the tip of the case, and the ultrasonic sensor (Sti) (Sto) (Sbi) (Sbo) are attached to the fixed-side track member (3).

  Further, as shown in FIGS. 9 and 10, the configuration of the hub unit can be changed to eliminate the strength reduction accompanying the sensor installation.

  9 and 10, the sensor-equipped rolling bearing device includes an automobile hub unit (21) and a sensor device (22).

  The hub unit (21) is arranged in two rows between a stationary race member (23) fixed to the vehicle body side, a rotary race member (24) to which wheels are attached, and both members (23) (24). A plurality of rolling elements (balls) (25) and a cage (26) for holding the rolling elements (25) in each row are provided.

  The fixed-side raceway member (23) has an outer ring (fixed ring) function of the bearing, and includes a cylindrical portion (31) in which two rows of outer ring raceways are formed on the inner peripheral surface, and a cylindrical portion (31 ) And a flange portion (32) attached to the suspension device (vehicle body side portion) with a bolt.

  The rotating side raceway member (24) has a large diameter portion (34) having a first raceway groove (34a) and a small diameter portion (35) having an outer diameter smaller than the diameter of the first raceway groove (34a). The inner ring (33), and the inner ring (33), the inner ring (33), which has a small diameter part (35) and is fitted to the outer diameter, and the right side is in close contact with the left side of the large diameter part (34) of the inner shaft (33). (36) Near the right end of the inner shaft (33), there is provided a flange portion (37) to which a plurality of bolts (38) for mounting a wheel are fixed. A raceway groove (36a) is formed on the right side of the inner ring (36) so as to be parallel to the raceway groove (34a) of the inner shaft (33). A sealing device (39) is provided between the right end portion of the fixed race member (23) and the inner shaft (33). A male screw is provided at the left end of the small diameter portion (35) of the inner shaft (33), and the inner ring (36) is connected to the inner shaft (33) by a nut (40) screwed to the male screw. It is fixed to. A cover (41) is covered with the left end portion of the fixed-side raceway member (23). Although not shown in the drawings, the inner ring and the inner shaft may be fixed by plastically deforming the end of the inner shaft.

  The sensor device (22) is a multi-vibrator ultrasonic sensor (Sti) (Sbi) that detects the force (rolling element load) acting between the fixed side raceway member (23) and the inner row rolling elements (25). And the ultrasonic sensors (Sto) (Sbo) that detect the rolling element load of the rolling elements (25) in the outer row, and the output of these ultrasonic sensors (Sti) (Sbi) (Sto) (Sbo) And processing means (see FIG. 7).

  The ultrasonic sensors (Sti), (Sto), (Sbi), and (Sbo) are the uppermost portion of the fixed-side track member (23) shown in FIG. ) And the lowermost portion of the fixed race member (23) = bottom (Sbi) (Sbo) (position indicated by D in FIG. 2) (Position indicated by B in FIG. 2) and the front side of the upper and lower intermediate parts of the fixed-side track member (23) = front part (position indicated by C in FIG. 2). However, the number and arrangement of the ultrasonic sensors are not limited to this.

  The fixed-side track member (23) is provided with a sensor installation protrusion (42) having an isosceles right triangle shape in cross section so that the right-angled portion is at the tip of the protrusion (42). The ultrasonic sensors (Sti) and (Sto) are attached to two surfaces sandwiching the right angle portion of the projecting portion (42). Since this attachment structure is the same as that shown in FIG. 3 in an enlarged manner, the same components as those in FIG. Of course, instead of the same configuration as in FIG. 3, the configuration of FIG. According to this embodiment, the sensor installation location is reinforced by the projecting portion (42), so that strength reduction due to sensor installation is prevented. The protruding portion (42) may be provided only at the sensor installation position (the uppermost portion, the lowermost portion, and the upper and lower intermediate portions of the fixed-side track member (23)), and is continuous in the circumferential direction (the cross-sectional shape is constant) It may be provided).

  In addition, in the above, although the hub unit with a sensor was demonstrated, the said sensor apparatus can be integrated and used for various rolling bearings other than a hub unit.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a rolling bearing device with a sensor according to the present invention. FIG. 2 is a side view of the same. FIG. 3 is an enlarged longitudinal sectional view of the main part of FIG. 1 showing the mounting structure of the ultrasonic sensor. FIG. 4 is a diagram illustrating an example of an echo waveform obtained by the ultrasonic sensor. FIG. 5 is a graph showing the relationship between the echo amplitude obtained by the ultrasonic sensor and the mounting surface roughness. FIG. 6 is a graph showing the relationship between the echo ratio obtained by the ultrasonic sensor and the rolling element load. FIG. 7 is a block diagram showing the processing means of the sensor-equipped rolling bearing device according to the present invention. FIG. 8 is an enlarged longitudinal sectional view corresponding to FIG. 3 showing another embodiment of the ultrasonic sensor mounting structure. FIG. 9 is a longitudinal sectional view showing a sensor-equipped rolling bearing device according to a second embodiment of the present invention. FIG. 10 is an enlarged vertical cross-sectional view of the main part of FIG. 9 showing the attachment structure of the ultrasonic sensor.

Explanation of symbols

(1) Rolling bearing
(2) Sensor device
(3) Fixed side raceway member
(3b) Female thread
(3c) Female thread
(4) Rotating track member
(5) Ball (rolling element)
(Sti) (Sto) (Sbi) (Sbo) Ultrasonic sensor
(22) Sensor device
(23) Fixed track member
(31) Case
(31a) Male thread
(32) Vibrator
(61) Case
(61a) Flange
(62) Vibrator
(63) Bolt

Claims (4)

In a rolling bearing device with a sensor provided with a rolling bearing having a stationary race member, a rotating race member and rolling elements, and a sensor device,
The rolling bearing is an automotive hub unit, and the sensor device is provided at least at two locations spaced apart in the circumferential direction of the fixed-side raceway member, and an ultrasonic sensor that detects the rolling element load as an echo ratio, A processing means for obtaining at least a vertical component and a horizontal component among the three directions of the load acting on the rolling bearing from the output of the ultrasonic sensor, and an expression for obtaining the load acting on the hub unit from the rolling element load A rolling bearing device with a sensor , wherein the processing means is provided with the following formula (1) .
f1 = a + bFy + cFz + dMx
f2 = a + bFy + cFx + dMz
f3 = a + bFy-cFz-dMx
f4 = a + bFy−cFx−dMz Equation (1)
f5 = a−bFy + cFz−dMx
f6 = a−bFy + cFx−dMz
f7 = a−bFy−cFz + dMx
f8 = a−bFy−cFx + dMz
Where a: rolling element load due to preload of the hub unit, b, c, d: coefficients not depending on external force, Fx, Fy, Fz: front-rear (x-axis) direction component, left-right (y-axis) direction component, and upper and lower (Z-axis) direction component, Mx, Mz: x-axis, moment about z-axis, f1-f8: rolling element load at each sensor position. The number of sensors is two, and the processing means obtains the vertical component and the horizontal component of the load acting on the rolling bearing from two appropriate formulas of formula (1) and formula (2) below. The rolling bearing device with a sensor according to claim 1 .
Mx = r × Fy + e × Fz (2)
However, r: Wheel rolling radius, e: Deviation between the action point of Fz and the hub unit center in the y-axis direction. The number of sensors is four, and the processing means uses four appropriate expressions in the expression (1), the expression (2), and the following expression (3), the vertical component and the longitudinal component of the load acting on the rolling bearing. The rolling bearing device with a sensor according to claim 1 , wherein the rolling bearing device with a sensor is used for obtaining a left-right component.
My = r × Fx ……… Formula (3)
However, My: moment about the y-axis. In a rolling bearing device with a sensor provided with a rolling bearing having a stationary race member, a rotating race member and rolling elements, and a sensor device,
The sensor device is provided in at least two places with a predetermined interval in the circumferential direction of the fixed-side track member, and detects the rolling element load as an echo ratio, and acts on the rolling bearing from the output of each ultrasonic sensor. Processing means for obtaining at least a vertical component and a horizontal component among the three directional components of the load,
The load acting on the rolling bearing is calculated using the echo ratio measured by the ultrasonic sensor, and the following formulas (4) to (6) are provided in the processing means as formulas for that purpose. and to Ruse capacitors rolling bearing device.
j1 = k + lFy + mFz + nMx
j2 = k + lFy + mFx + nMz
j3 = k + lFy-mFz-nMx
j4 = k + lFy−mFx−nMz Equation (4)
j5 = k−1Fy + mFz−nMx
j6 = k−1Fy + mFx−nMz
j7 = k−1Fy−mFz + nMx
j8 = k-1Fy-mFx + nMz
Mx = r × Fy + e × Fz (5)
My = r × Fx Equation (6)
Where k: echo ratio due to hub unit preload, l, m, n: coefficients independent of external force, Fx, Fy, Fz: longitudinal (x-axis) direction component, lateral (y-axis) direction component and vertical ( z-axis) direction component, Mx, My, Mz: x-axis, y-axis, moment about z-axis, j1 to j8: echo ratio at each sensor position, r: wheel rolling radius, e: Fz in y-axis direction Deviation between the operating point and the hub unit center.

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