JP4370884B2 - Load measuring device for rolling bearing units - Google Patents

Description

  A load measuring device for a rolling bearing unit that is an object of the present invention is, for example, a load (one or both of a radial load and an axial load) applied to a rolling bearing unit for supporting wheels of a vehicle such as an automobile or a railway vehicle. ) Is measured and used to ensure the running stability of the vehicle.

  For example, an automobile wheel is rotatably supported by a double row angular rolling bearing unit with respect to a suspension device. In order to ensure the running stability of automobiles, vehicle running stabilizers such as an antilock brake system (ABS), a traction control system (TCS), and a vehicle stability control system (VSC) are used. . In order to control such various vehicle running stabilizers, signals such as the rotational speed of the wheels and the acceleration in each direction applied to the vehicle body are required. In order to perform higher-level control, it may be preferable to know the magnitude of a load (one or both of a radial load and an axial load) applied to the rolling bearing unit via the wheel.

  In view of such circumstances, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. The rolling bearing unit with a load measuring device of the first example of this conventional structure measures a radial load and is configured as shown in FIG. A hub 2 for coupling and fixing the wheel is supported on the inner diameter side of the outer ring 1 supported by the suspension device. The hub 2 has a hub body having a rotation-side flange 3 for fixing a wheel at an outer end thereof (an end portion on the outer side in the width direction when assembled to a vehicle, and a left end portion in each drawing excluding FIG. 6). 4 and the inner end portion of the hub body 4 (the end portion on the center side in the width direction in the assembled state in the vehicle, the right end portion of each drawing excluding FIG. 6) and are held down by the nut 5. And an inner ring 6. A plurality of rolling rings are provided between the double row outer ring raceways 7 and 7 formed on the inner peripheral surface of the outer ring 1 and the double row inner ring raceways 8 and 8 formed on the outer peripheral surface of the hub 2. The moving bodies 9a and 9b are arranged to freely rotate the hub 2 on the inner diameter side of the outer ring 1.

  A mounting hole 10 that diametrically penetrates the outer ring 1 is formed in a substantially vertical direction at an upper end portion of the outer ring 1 in a portion between the double row outer ring raceways 7 and 7 at an intermediate portion in the axial direction of the outer ring 1. Yes. In the mounting hole 10, a circular rod-shaped (round bar-shaped) displacement sensor 11, which is a load measuring sensor, is mounted. This displacement sensor 11 is a non-contact type, and the detection surface provided on the front end surface (lower end surface) is closely opposed to the outer peripheral surface of the sensor ring 12 fitted and fixed to the intermediate portion in the axial direction of the hub 2. When the distance between the detection surface and the outer peripheral surface of the sensor ring 12 changes, the displacement sensor 11 outputs a signal corresponding to the amount of change.

  In the case of the conventional rolling bearing unit with a load measuring device configured as described above, the load applied to the rolling bearing unit can be obtained based on the detection signal of the displacement sensor 11. That is, the outer ring 1 supported by the vehicle suspension device is pushed downward by the weight of the vehicle, whereas the hub 2 supporting and fixing the wheel tends to stop at the same position. For this reason, the greater the weight, the greater the deviation between the center of the outer ring 1 and the center of the hub 2 based on the elastic deformation of the outer ring 1, the hub 2, and the rolling elements 9a, 9b. The distance between the detection surface of the displacement sensor 11 and the outer peripheral surface of the sensor ring 12 provided at the upper end of the outer ring 1 becomes shorter as the weight increases. Therefore, if the detection signal of the displacement sensor 11 is sent to the controller, the radial load applied to the rolling bearing unit in which the displacement sensor 11 is incorporated can be obtained from a relational expression or a map obtained beforehand through experiments or the like. Based on the load applied to each rolling bearing unit thus obtained, the ABS is appropriately controlled and the driver is informed of the poor loading state.

  In the conventional structure shown in FIG. 3, in addition to the load applied to the rolling bearing unit, the rotational speed of the hub 2 can also be detected. For this purpose, the rotational speed detecting encoder 13 is fitted and fixed to the inner end of the inner ring 6, and the rotational speed detecting sensor 15 is supported on the cover 14 attached to the inner end opening of the outer ring 1. Yes. And the detection part of this rotational speed detection sensor 15 is made to oppose the to-be-detected part of the said encoder 13 for rotational speed detection through the measurement clearance gap.

  When the rolling bearing unit incorporating the rotational speed detecting device as described above is used, the rotational speed detecting encoder 13 is rotated together with the hub 2 to which the wheel is fixed, and the detected portion of the rotational speed detecting encoder 13 is rotated as described above. When traveling in the vicinity of the detection unit of the speed detection sensor 15, the output of the rotation speed detection sensor 15 changes. The frequency at which the output of the rotational speed detection sensor 15 changes in this way is proportional to the rotational speed of the wheel. Therefore, if the output signal of the rotational speed detection sensor 15 is sent to a controller (not shown), ABS and TCS can be controlled appropriately.

  The rolling bearing unit with a load measuring device of the first example of the conventional structure as described above is for measuring the radial load applied to the rolling bearing unit, but the structure for measuring the axial load applied to the rolling bearing unit is also, It is described in Patent Document 2 and the like and has been conventionally known. FIG. 4 shows a rolling bearing unit with a load measuring device for measuring an axial load described in Patent Document 2. As shown in FIG. In the case of the second example of this conventional structure, the rotation side flange 3a for supporting the wheel is fixed on the outer peripheral surface of the outer end portion of the hub 2a. A fixed-side flange 17 is fixed to the outer peripheral surface of the outer ring 1a for supporting and fixing the outer ring 1a to a knuckle 16 constituting a suspension device. A plurality of rolling rings are respectively provided between the double row outer ring raceways 7 and 7 formed on the inner peripheral surface of the outer ring 1a and the double row inner ring raceways 8 and 8 formed on the outer peripheral surface of the hub 2a. By providing the moving bodies 9a and 9b so as to be able to roll, the hub 2a is rotatably supported on the inner diameter side of the outer ring 1a.

  Further, a load sensor 20 is attached to a part surrounding the screw hole 19 for screwing the bolt 18 for connecting the fixed side flange 17 to the knuckle 16 at a plurality of positions on the inner side surface of the fixed side flange 17. Has been established. Each load sensor 20 is sandwiched between the outer side surface of the knuckle 16 and the inner side surface of the fixed-side flange 17 in a state where the outer ring 1 a is supported and fixed to the knuckle 16.

  In the case of the load measuring device of the rolling bearing unit of the second example having such a conventional structure, when an axial load is applied between a wheel (not shown) and the knuckle 16, the outer surface of the knuckle 16 and the fixed side flange 17 The inner surface strongly presses the load sensors 20 from both sides in the axial direction. Therefore, the axial load applied between the wheel and the knuckle 16 can be obtained by summing up the measured values of the load sensors 20. Although not shown, Patent Document 3 describes a method of obtaining the revolution speed of the rolling element from the vibration frequency of a member corresponding to an outer ring having a reduced rigidity, and measuring the axial load applied to the rolling bearing. ing.

  In the case of the first example of the conventional structure shown in FIG. 3 described above, the load applied to the rolling bearing unit is measured by measuring the displacement in the radial direction between the outer ring 1 and the hub 2 by the displacement sensor 11. However, since the displacement amount in the radial direction is small, it is necessary to use a highly accurate displacement sensor 11 in order to obtain this load with high accuracy. Since high-precision non-contact sensors are expensive, it is inevitable that the cost of the entire rolling bearing unit with a load measuring device increases.

  In the case of the second example of the conventional structure shown in FIG. 4 described above, it is necessary to provide as many load sensors 20 as the number of bolts 18 for supporting and fixing the outer ring 1a to the knuckle 16. For this reason, coupled with the fact that the load sensor 20 itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. Further, the method described in Patent Document 3 requires that the rigidity of a part of the outer ring equivalent member be lowered, and it may be difficult to ensure the durability of the outer ring equivalent member. Further, since the revolution speed of the rolling element is obtained from the vibration frequency of the outer ring equivalent member, there is a problem that the revolution speed cannot be measured accurately.

  In view of such circumstances, the present inventors have previously described this rolling bearing unit based on the revolution speed of a pair of rolling elements (balls) constituting a rolling bearing unit which is a double row angular ball bearing. An invention relating to a load measuring device for a rolling bearing unit that measures a radial load or an axial load applied to the bearing is performed (Japanese Patent Application Nos. 2003-171715 and 172483). FIG. 5 shows a load measuring device for a rolling bearing unit according to the present invention. In the case of the structure according to the previous invention, the sensor unit 21 is inserted into the mounting hole 10a formed in the portion between the double-row outer ring raceways 7 and 7 at the intermediate portion in the axial direction of the outer ring 1 (outer ring equivalent member). A detecting portion 22 provided at the tip of the outer ring 1 protrudes from the inner peripheral surface of the outer ring 1. The detection unit 22 is provided with a pair of revolution speed detection sensors 23a and 23b and one rotation speed detection sensor 15a.

  And the detection part of each revolution speed detection sensor 23a, 23b of these is provided in each retainer 24a, 24b which hold | maintained each rolling element 9a, 9b arrange | positioned in a double row freely, The revolution speed detection The revolving speeds of the rolling elements 9a and 9b are made freely detectable by being close to and facing the encoders 25a and 25b. Further, the rotational speed of the hub 2 can be detected by making the detection part of the rotational speed detection sensor 15a close to and opposed to the rotational speed detection encoder 13a externally fitted and fixed to the intermediate part of the hub 2 which is an inner ring equivalent member. It is said. According to the load measuring device for a rolling bearing unit according to the above invention having such a configuration, the load (radial) applied between the outer ring 1 and the hub 2 regardless of the fluctuation of the rotational speed of the hub 2. Load and axial load).

That is, in the case of the load measuring device for a rolling bearing unit according to the above-described prior invention, an arithmetic unit (not shown) performs the outer ring 1 and the hub 2 based on the detection signals sent from the sensors 23a, 23b, 15a. One or both of a radial load and an axial load applied between the two are calculated. For example, when the radial load is obtained, the computing unit obtains the sum of the revolution speeds of the rolling elements 9a and 9b in each row detected by the revolution speed detection sensors 23a and 23b, and the sum and the rotation speed. The radial load is calculated based on the ratio to the rotational speed of the hub 2 detected by the detection sensor 15a. Further, the axial load is obtained by calculating the difference between the revolution speeds of the rolling elements 9a and 9b in each row detected by the revolution speed detection sensors 23a and 23b, and this difference and the rotational speed detection sensor 15a are detected. Calculation is based on the ratio to the rotational speed of the hub 2. This point will be described with reference to FIG. In the following description, it is assumed that the contact angles α _a and α _b of the rolling elements 9 a and 9 b in the respective rows are the same in a state where the axial load Fy is not applied.

FIG. 6 schematically shows the wheel bearing rolling bearing unit shown in FIG. 5 described above and shows the action state of the load. Preloads F ₀ and F ₀ are applied to the rolling elements 9 a and 9 b arranged in a double row between the double row inner ring raceways 8 and 8 and the double row outer ring raceways 7 and 7. Further, a radial load Fz is applied to the rolling bearing unit during use due to the weight of the vehicle body or the like. Further, an axial load Fy is applied due to centrifugal force applied during turning. These preloads F ₀ , F ₀ , radial load Fz, and axial load Fy all affect the contact angles α (α _a , α _b ) of the rolling elements 9a, 9b. Then, the contact angle alpha _a, the alpha _b is changed, these rolling elements 9a, the revolution speed n _c of 9b changes. The diameter of the pitch circle of each of these rolling elements 9a, 9b is D, the diameter of each of these rolling elements 9a, 9b is d, the rotational speed of the hub 2 provided with each of the inner ring raceways 8, 8 is n _i , When the rotational speed of the outer race 1 provided with the outer ring raceway 7, 7 and n _o, the revolution speed n _c is expressed by the following equation (1).
n _c = {1− (d · cos α / D) · (n _i / 2)} + {1+ (d · cos α / D) · (n _o / 2)} --- (1)

As is clear from this equation (1), the rolling elements 9a, the revolution speed n _c of 9b, these rolling elements 9a, the contact angle α (α _a, α _b) of 9b varies in response to changes in As described above, the contact angles α _a and α _b change according to the radial load Fz and the axial load Fy. Thus the revolution speed n _c is changed according to these radial load Fz and the axial load Fy. In this example, the hub 2 is rotated, since the outer ring 1 is not rotated, specifically, with respect to the radial load Fz, the revolution speed n _c is slow enough to increase. As for the axial load Fy, the revolution speed of the row that supports the axial load Fy is increased, and the revolution speed of the row that does not support the axial load Fy is decreased. Therefore, on the basis of the revolution speed n _c, it will be asked to the radial load Fz and the axial load Fy.

However, the contact angle α which leads to a change in the revolution speed n _c, as well as the radial load Fz and the axial load Fy changes while associated with each other, also vary according to the preload F _0, F _0. Also, the revolution speed n _c is changed in proportion to the rotational speed n _i of the hub 2. Therefore, these radial load Fz, axial load Fy, the preload F _0, F _0, to be considered in conjunction all the rotational speed n _i of the hub 2, it is impossible to correctly determine the revolution speed n _c. Of these, the preloads F ₀ and F ₀ do not change according to the operating state, so it is easy to eliminate the influence by initial setting or the like. The radial load Fz with respect to this, the axial load Fy, the rotational speed n _i of the hub 2, since the constantly changing depending on the operating conditions, it is impossible to eliminate the influence by such initialization.

In the case of the prior invention in view of such circumstances, as described above, when the radial load Fz is obtained, the rolling elements 9a, 9b of the respective rows detected by the respective revolution speed detection sensors 23a, 23b are detected. By determining the sum of the revolution speeds, the influence of the axial load Fy is reduced. Further, when the axial load Fy is obtained, the influence of the radial load Fz is reduced by obtaining the difference between the revolution speeds of the rolling elements 9a and 9b in each row. Furthermore, in any case, possible to calculate the radial load Fz or the axial load Fy on the basis of the ratio of the above sum or difference, the rotational speed detecting sensor 15a is a rotational speed n _i of the hub 2 for detecting way, by eliminating the influence of the rotational speed n _i of the hub 2. However, the axial load Fy, when calculating on the basis of the rolling elements 9a, 9b ratio of the revolution speed of said each row, the rotational speed n _i of the hub 2 is not necessarily required.

  There are various other methods for calculating one or both of the radial load Fz and the axial load Fy based on the signals of the revolution speed detection sensors 23a and 23b. This method is described in detail in the aforementioned Japanese Patent Application Nos. 2003-171715 and 172483, and is not related to the gist of the present invention.

  The load measuring device for a rolling bearing unit according to the above-described invention includes a rotation speed detection encoder 13a, a rotation speed detection sensor 15a, revolution speed detection encoders 25a and 25b, revolution speed detection sensors 23a and 23b, and A load calculator for calculating a load applied between the outer ring 1 and the hub 2 based on detection signals of the sensors 15a, 23a, and 23b is provided. If any of the components of the load measuring device of such a rolling bearing unit, or a defect occurs in the wiring or the like, the expected performance cannot be exhibited. For example, the signal representing the rotational speed of the hub 2 detected by the rotational speed detection sensor 15a is used to calculate the load applied between the outer ring 1 and the hub 2 and also to control ABS and TCS. ing. Therefore, if an abnormality occurs in the detection signal of the rotational speed detection sensor 15a, the ABS and TCS are not properly controlled, and the traveling state of the vehicle may become unstable.

If it is possible to detect that there is an abnormality in the load calculator that receives the detection signal of the rotation speed detection sensor 15a, or the detection signal of the rotation speed detection sensor 15a and the revolution speed detection sensors 23a and 23b, For example, fail-safe is possible in which the control of the ABS or TCS is stopped and returned to normal brake control. However, it is difficult to determine whether or not there is an abnormality in the detection signal of the rotational speed detection sensor 15a, except in the case where the wiring is completely disconnected, with a conventionally known detection method .

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Publication No.62-3365

  The present invention has been invented to realize a structure that can easily and reliably determine whether or not there is an abnormality in the detection signal of the rotational speed detection sensor 15a in view of the above-described circumstances.

The load measuring device of the rolling bearing unit of the present invention includes an outer ring equivalent member, an inner ring equivalent member, a plurality of rolling elements, a revolution speed detection sensor, a rotation speed detection sensor, a load calculator, a rotation speed, An arithmetic unit and a comparator are provided.
Of these, the outer ring equivalent member has an outer ring raceway on the inner peripheral surface.
The inner ring equivalent member has an inner ring raceway on the outer peripheral surface, and is disposed concentrically with the outer ring equivalent member on the inner diameter side of the outer ring equivalent member.
Each of the rolling elements is provided with a contact angle between the outer ring raceway and the inner ring raceway.
The revolution speed detection sensor is for detecting the revolution speed of each rolling element.
The rotational speed detection sensor is for detecting the rotational speed of the rotation-side race that is a rotating member of the outer ring equivalent member and the inner ring equivalent member.
The load calculator calculates a load applied between the outer ring equivalent member and the inner ring equivalent member based on a detection signal of the rotation speed detection sensor and a detection signal of the revolution speed detection sensor. Is.
The rotational speed calculator calculates the rotational speed of the rotating raceway based on the detection signal of the revolution speed detecting sensor.
The comparator represents a first signal representing the rotation speed of the rotation-side raceway calculated by the rotation speed calculator and a rotation speed of the rotation-side raceway sent from the rotation speed detection sensor. Compare with the second signal.
Further, the comparator is large enough not to be caused by a change in contact angle based on a load applied between the outer ring equivalent member and the inner ring equivalent member, which is set in advance between the first and second signals. When there is a difference that exceeds a threshold value, the rotation speed detection sensor has a function of issuing a signal indicating that there is an abnormality .

The load measuring device of the rolling bearing unit of the present invention configured as described above can measure the load applied to the rolling bearing unit by detecting the revolution speed of the rolling element. That is, when a load is applied to a rolling bearing unit such as a ball bearing, the contact angle of the rolling elements (balls) changes, and the revolution speed of each rolling element changes. Therefore, if this revolution speed is detected, a load acting between the outer ring equivalent member and the inner ring equivalent member can be obtained.
Furthermore, according to the load measuring apparatus of the rolling bearing unit of the present invention, it can be easily and reliably determined whether or not there is an abnormality in the detection signal of the rotational speed detection sensor. For this reason, it is possible to perform fail-safe by detecting that there is an abnormality in the rotational speed detection sensor and stopping the control of the ABS or TCS and returning to the normal brake control.

Preferably, when carrying out the present invention, as described in claim 2, the outer ring equivalent member having a double row outer ring raceway on the inner peripheral surface, and the inner ring equivalent member having a double row inner ring raceway on the outer peripheral surface. The rolling elements are arranged in double rows between the outer ring raceways and the inner ring raceways. The first signal is a signal calculated based on the average value of the revolution speeds of the rolling elements arranged in these double rows.
With this configuration, the first signal can be obtained with high accuracy.

In this case, as described in claim 3, the rolling elements can be freely rolled by a pair of cages in a state where the respective rolling elements are provided with the directions of contact angles being reversed between the rows. Hold. Also, a pair of revolution speed detecting encoders whose characteristics are changed alternately and at equal intervals in the circumferential direction are provided in a part of each of the cages. Further, a pair of revolution speed detection sensors for detecting the revolution speed of the rolling elements in each row as the rotation speed of each cage, and the respective detecting portions are detected by the respective revolution speed detection encoders. Provided facing the surface. Then, the load calculator calculates a load applied between the outer ring equivalent member and the inner ring equivalent member based on the detection signal sent from each of the revolution speed detection sensors.
If configured in this way, it is possible to obtain a load applied between the outer ring equivalent member and the inner ring equivalent member with high accuracy and to effectively detect an abnormality in the detection signal of the rotational speed detection sensor. realizable.

In this case, more preferably, as described in claim 4, a double-row angular outer ring raceway formed on the inner peripheral surface of an outer ring equivalent member that does not rotate during use, with each rolling element as a ball, A contact angle of the back combination type is imparted to a plurality of balls respectively provided between the inner ring raceway of the double row angular type formed on the outer peripheral surface of the inner ring equivalent member that rotates during use.
For example, as described in claim 5, the load calculator is configured to calculate the sum of the revolution speed of the rolling elements in one row and the revolution speed of the rolling elements in the other row, and the rotation speed of the inner ring equivalent member. Based on the ratio, a radial load applied between the inner ring equivalent member and the outer ring equivalent member is calculated.
Alternatively, as described in claim 6, the load calculator is configured to calculate a difference between the revolution speed of the rolling elements in one row and the revolution speed of the rolling elements in the other row, and the rotation speed of the inner ring equivalent member. Based on the ratio, an axial load applied between the outer ring equivalent member and the inner ring equivalent member is calculated.
Alternatively, as described in claim 7, the load calculator may be configured such that the outer ring equivalent member and the inner ring are based on a ratio between the revolution speed of the rolling elements in one row and the revolution speed of the rolling elements in the other row. The axial load applied between the corresponding members is calculated.
If comprised in this way, with a highly rigid rolling bearing unit, the load added between these outer ring equivalent members and inner ring equivalent members can be calculated | required with high precision.

  FIG. 1 shows a first embodiment of the present invention. In the case of the present embodiment, the structure of the wheel supporting rolling bearing unit, the structure for detecting the rotational speed of the hub 2 constituting the wheel supporting rolling bearing unit, and the revolution speed of each of the rolling elements 9a and 9b are as follows. The structure for detection is the same as the structure according to the prior invention shown in FIG. Further, based on the detection signal of the rotational speed detection sensor 15a and the detection signal of the pair of revolution speed detection sensors 23a and 23b, a load (a radial load and an axial load) applied between the outer ring 1 and the hub 2 is determined. The configuration of the load calculator for calculating one or both) is the same as in the case of the previous invention. That is, the detection signal of the rotation speed detection sensor 15a is passed through the rotation speed calculation circuit 26, and the detection signal of the pair of revolution speed detection sensors 23a, 23b is passed through the revolution speed calculation circuit 27. 28, and the load is calculated. In practice, the revolution speed calculation circuit 27 is provided for each of the revolution speed detection sensors 23a and 23b. Therefore, the same parts as those in the structure according to the above-described invention are denoted by the same reference numerals, and redundant description is omitted or simplified. Hereinafter, the characteristic parts of the present embodiment will be mainly described.

In the case of the present embodiment, the detection signal of the rotational speed detection sensor 15a is used to obtain the load in relation to the detection signals of the revolution speed detection sensors 23a and 23b, as well as the ABS or TCS. Used for control. Further, the detection signals of the respective revolution speed detection sensors 23a and 23b are sent to the rotational speed calculator 29, and based on the detection signals (average values) of the respective revolution speed detection sensors 23a and 23b, It is configured to calculate the rotation speed. The rotation speed calculator 29 uses the above-described equation (1), so that the rotation speed of the hub 2 is based on the detection signals (average values) of the revolution speed detection sensors 23a and 23b. Is calculated. In this case, the value of the contact angle α used in the above equation (1) is a standard value (design value). In this way, the first signal A representing the rotational speed obtained based on the detection signals of the respective revolution speed detection sensors 23 a and 23 b is input to the comparator 30. A second signal B representing the rotational speed of the hub 2 obtained based on the detection signal of the rotational speed detection sensor 15 a is also input to the comparator 30.

When there is a difference exceeding a preset threshold value between the first and second signals A and B, the comparator 30 generates a signal C indicating that the rotational speed detection sensor 15a is abnormal . It emits toward the controller 31. When the controller 31 receives this abnormal signal, it stops the ABS and TCS functions and turns on a warning light provided on the dashboard of the driver's seat to alert the driver for repairs. To emit.

It should be noted that the threshold value of the comparator 30 is set to such a large value that the change in contact angle based on the load applied to the wheel-supporting rolling bearing unit does not occur with respect to the revolution speed of the rolling elements 9a and 9b in each row. That is, the contact angles α _a and α _b of the rolling elements 9a and 9b in each row change based on variations within design tolerances and the load. The amount of change in each of these contact angles α _a and α _b due to such a reason may reach 5 to 10 degrees at the maximum, and along with this change, the revolution speed of the rolling elements 9a and 9b in each row is , Change by a few percent. Therefore, the threshold is defined to be about 10 to several tens of percent. That is, the comparator 30 outputs the second signal B, that is, the rotation speed obtained based on the first signal A, that is, the detection signal of each revolution speed detection sensor 23a, 23b. When the rotational speed obtained based on the detection signal of the rotational speed detection sensor 15a deviates by 10 to several tens of percent, a signal C indicating that there is an abnormality is issued to the controller 31.

  As described above, according to the load measuring device of the rolling bearing unit of the present embodiment, it can be easily and reliably determined whether or not the detection signal of the rotational speed detection sensor 15a is abnormal. For this reason, it is possible to perform fail-safe by detecting that there is an abnormality in the rotational speed detection sensor 15a, and stopping the function of the ABS or TCS to return to the normal travel mode.

  FIG. 2 shows a second embodiment of the present invention. In the case of the present embodiment, the revolution speed detection unit 32 incorporating the pair of revolution speed detection sensors 23a and 23b and the rotation speed detection sensor 15b are configured separately from each other. For this reason, in this example, the rotational speed detecting encoder 13b is fitted and fixed to the inner end of the inner ring 6 constituting the hub 2, and fixed to the cover 14a fitted and fixed to the inner end of the outer ring 1. The detection portion of the rotational speed detection sensor 15b is opposed to the detection surface of the rotational speed detection encoder 13b.

  In this embodiment, the revolution speed detection sensors 23a and 23b and the rotation speed detection sensor 15b are separately arranged, so that the sensors 23a, 23b and 15b can be simultaneously broken. The property can be lowered as compared with the case of Example 1 described above. For this reason, more reliable fail safe can be achieved as compared with the first embodiment.

FIG. 3 is a partial cutaway view showing Example 1 of the present invention. The fragmentary sectional view which shows the same Example 2. FIG. Sectional drawing of the rolling bearing unit which incorporated the sensor for radial load measurement known conventionally. Sectional drawing of the rolling bearing unit which incorporated the sensor for axial load measurement conventionally known. Sectional drawing of the load measuring apparatus of the rolling bearing unit which concerns on a prior invention. The schematic diagram for demonstrating the reason for which the load added to a rolling bearing unit is calculated | required.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Outer ring 2, 2a Hub 3, 3a Rotation side flange 4 Hub body 5 Nut 6 Inner ring 7 Outer ring raceway 8 Inner ring raceway 9a, 9b Rolling element 10, 10a Mounting hole 11 Displacement sensor 12 Sensor ring 13, 13a, 13b Rotational speed Detection encoder 14, 14a Cover 15, 15a, 15b Rotational speed detection sensor 16 Knuckle 17 Fixed flange 18 Bolt 19 Screw hole 20 Load sensor 21 Sensor unit 22 Detection section 23a, 23b Revolution speed detection sensor 24a, 24b Cage 25a, 25b Revolution speed detection encoder 26 Rotational speed calculation circuit 27 Revolution speed calculation circuit 28 Load calculator 29 Rotational speed calculator 30 Comparator 31 Controller 32 Revolution speed detection unit

Claims (9)

An outer ring equivalent member having an outer ring raceway on the inner peripheral surface, an inner ring equivalent member having an inner ring raceway on the outer peripheral surface disposed concentrically with the outer ring equivalent member on the inner diameter side of the outer ring equivalent member, the inner ring raceway and the outer ring A plurality of rolling elements provided with a contact angle between them and a raceway, a revolution speed detecting sensor for detecting the revolution speed of each rolling element, the outer ring equivalent member, and the inner ring equivalent member Based on a rotation speed detection sensor for detecting the rotation speed of the rotating raceway, which is a rotating member, and a detection signal of the rotation speed detection sensor and a detection signal of the revolution speed detection sensor. A load calculator for calculating a load applied between the outer ring equivalent member and the inner ring equivalent member, and a rotation speed calculation for calculating a rotation speed of the rotation side raceway ring based on a detection signal of the revolution speed detection sensor. And The first signal representing the rotation speed of the rotation-side raceway calculated by the rotation speed calculator is compared with the second signal representing the rotation speed of the rotation-side raceway sent from the rotation speed detection sensor. The comparator is generated by a change in contact angle based on a load applied between the outer ring equivalent member and the inner ring equivalent member, which is preset between the first and second signals. A load measuring device for a rolling bearing unit having a function of issuing a signal indicating that there is an abnormality in the rotational speed detection sensor when there is a difference exceeding a threshold value, which is a large value that is not large .   The outer ring equivalent member has a double row outer ring raceway on the inner peripheral surface, the inner ring equivalent member has a double row inner ring raceway on the outer peripheral surface, and the rolling elements are double row between each outer ring raceway and each inner ring raceway. The load of the rolling bearing unit according to claim 1, wherein the first signal is a signal calculated based on an average value of revolution speeds of the rolling elements arranged in the double row. measuring device.   Each rolling element is held by a pair of cages in a state in which the direction of the contact angle is reversed between each row, and the characteristics are alternately and with respect to the circumferential direction. A pair of revolution speed detecting encoders changed at intervals is provided in a part of each cage, and each revolution speed of the rolling elements in each row is detected as a rotation speed of each cage. A pair of revolution speed detection sensors are provided in a state in which the respective detection portions are opposed to the detected surfaces of the respective revolution speed detection encoders, and the load calculator is connected to each revolution speed detection sensor. The load measuring device for a rolling bearing unit according to claim 2, wherein a load applied between the outer ring equivalent member and the inner ring equivalent member is calculated based on the detection signal sent.   Each rolling element is a ball, a double row angular type outer ring raceway formed on the inner peripheral surface of the outer ring equivalent member that does not rotate during use, and a double row angular type formed on the outer peripheral surface of the inner ring equivalent member that rotates during use 4. The load measuring device for a wheel support rolling bearing unit according to claim 3, wherein a plurality of balls provided between the inner ring raceway and the inner ring raceway are each provided with a back combination type contact angle.   The load calculator calculates the inner ring equivalent member and the outer ring equivalent member based on the ratio between the revolution speed of the rolling element in one row and the revolution speed of the rolling element in the other row and the rotation speed of the inner ring equivalent member. The load measuring device for a wheel bearing rolling bearing unit according to claim 4, wherein a radial load applied between the wheel support and the wheel bearing is calculated.   The load calculator calculates the inner ring equivalent member and the outer ring equivalent member based on the ratio between the revolution speed of the rolling element in one row and the revolution speed of the rolling element in the other row and the rotation speed of the inner ring equivalent member. The load measuring device for a wheel bearing rolling bearing unit according to claim 4, wherein an axial load applied between the wheel bearing and the rolling bearing unit is calculated.   The load calculator calculates an axial load applied between the outer ring equivalent member and the inner ring equivalent member based on a ratio between the revolution speed of the rolling elements in one row and the revolution speed of the rolling elements in the other row. Item 5. A load measuring device for a wheel-supporting rolling bearing unit according to Item 4. The load measuring device for a wheel bearing rolling bearing unit according to any one of claims 2 to 7, wherein the pair of revolution speed detecting sensors and the rotational speed detecting sensor constitute a single sensor unit. The load of the wheel bearing rolling bearing unit according to any one of claims 2 to 7, wherein the revolution speed detection unit incorporating the pair of revolution speed detection sensors and the rotation speed detection sensor are separate from each other. measuring device.

Images