JP2005098771A - Load-measuring device of rolling bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a structure capable of ensuring the strength of an outer wheel 1, reducing its weight and exactly obtaining the load working in between a hub 2b and the outer wheel 1. <P>SOLUTION: Passage of rotors 9a, 9b constituting each series is detected, with a magnetic detection type revolution speed detection sensor 23 placed on the outer circumference of the wheel 1, to detect the revolving speed. A computing unit calculates the load, based on the detection signal of the revolution detection sensor 23. Since it is not necessary to form a penetration hole for attachment hole in the outer wheel 1 to place the revolution detection sensor 23, weight reduction of the outer wheel 1 is possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  A rolling bearing unit load measuring apparatus according to the present invention measures a load (one or both of a radial load and an axial load) applied to a rolling bearing unit for supporting a wheel of a vehicle such as an automobile or a railway vehicle. It is 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 includes a hub main body 4 having a rotation side flange 3 for fixing a wheel at an outer end portion thereof (an end portion on the outer side in the width direction when assembled to a vehicle, the left end portion in FIGS. 1 to 4). The inner ring 6 that is externally fitted to 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 and the right end portion in FIGS. 1 to 4) and held down by the nut 5. Prepare. 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. 2, the rotational speed of the hub 2 can be detected in addition to the load applied to the rolling bearing unit. For this purpose, the sensor rotor 13 is fitted and fixed to the inner end portion of the inner ring 6, and the rotational speed detection sensor 15 is supported by a cover 14 attached to the inner end opening of the outer ring 1. And the detection part of this sensor 15 for rotational speed detection is made to oppose the to-be-detected part of the said sensor rotor 13 via a measurement clearance gap.

  When the rolling bearing unit incorporating the rotational speed detection device as described above is used, the sensor rotor 13 rotates together with the hub 2 to which the wheel is fixed, and the detected portion of the sensor rotor 13 is connected to the rotational speed detection sensor 15. When traveling in the vicinity of the detection unit, the output of the rotational 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. 3 shows a rolling bearing unit with a load measuring device for measuring an axial load described in Patent Document 2. 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. 2 described above, the displacement 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. 3 described above, it is necessary to provide as many load sensors 20 as 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.

  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. 4 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 26 that is externally fitted and fixed to the intermediate part of the hub 2 that is an inner ring equivalent member. It is said. According to the load measuring device for a rolling bearing unit according to the prior invention having such a configuration, a load (a radial load and a load) applied between the outer ring 1 and the hub 2 regardless of fluctuations in the rotational speed of the hub 2. Thrust load).

That is, in the case of the load measuring device for a rolling bearing unit according to the above-described invention, an arithmetic unit (not shown) is configured to output the outer ring 1 and the hub 2 based on 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. 5 schematically shows the rolling bearing unit for supporting the wheel shown in FIG. 4 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, the 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.

  In the case of the rolling bearing unit load measuring device according to the above-described prior invention, the sensor unit 21 is inserted into the intermediate portion of the outer ring 1 in order to measure the revolution speed of the rolling elements 9a and 9b arranged in a double row. A mounting hole 10a is formed. For this reason, it is difficult to reduce the weight of the rolling bearing unit by securing the strength of the outer ring 1. On the other hand, in recent years, there has been an increasing demand for improving the performance of automobiles centered on driving performance such as fuel efficiency and driving stability. Further, in order to improve traveling performance, it is known that it is important to reduce the weight of a member serving as a so-called unsprung load, which is a portion existing on the wheel side of the spring incorporated in the suspension device. For these reasons, it is strongly desired to reduce the weight of the rolling bearing unit. However, the weight reduction of the outer ring 1 in which the mounting hole 10a is formed is smaller than the outer ring in which the through hole such as the mounting hole is not formed. It becomes difficult. Although the through hole is not formed even in the structure described in Patent Document 3, in order to reduce the rigidity of a part of the outer ring equivalent member, both durability and weight reduction of the outer ring equivalent member are achieved. Is difficult.

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

  In view of the circumstances as described above, the present invention has a structure that does not reduce the rigidity of the outer ring constituting the rolling bearing unit, such as by forming a through hole. The invention was invented to realize a structure that requires a load to be applied.

A load measuring device for a rolling bearing unit according to the present invention includes an outer ring equivalent member, an inner ring equivalent member, a plurality of rolling elements, a revolution speed detection sensor, and a calculator.
Of these, the outer ring equivalent member has an outer ring raceway on the inner peripheral surface.
The inner ring raceway is disposed concentrically with the outer ring equivalent member on the inner diameter side of the outer ring equivalent member, and has an inner ring raceway on the outer peripheral surface.
Each of the rolling elements is provided with a contact angle between the inner ring raceway and the outer ring raceway.
The revolution speed detection sensor detects the revolution speed of each rolling element.
The computing unit calculates a load applied between the outer ring equivalent member and the inner ring equivalent member based on a detection signal sent from the revolution speed detection sensor.
Further, each of the rolling elements is made of a magnetic material, and the revolution speed detection sensor is installed on the outer peripheral surface of the outer ring equivalent member, and has magnetic characteristics associated with the passage of the rolling elements through the outer ring equivalent member. The revolution speed is detected by detecting the change.

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. In order to reliably detect the revolution speed of the rolling elements, it is preferable to magnetize each rolling element as described in claim 2.
Furthermore, in the load measuring device of the rolling bearing unit according to the present invention, the revolution speed sensor is installed on the outer peripheral surface of the outer ring equivalent member, and the change in magnetic characteristics accompanying the passage of the respective rolling elements is detected via the outer ring equivalent member. Since the revolution speed is detected by detection, it is not necessary to form a through hole such as a mounting hole in the outer ring equivalent member or to lower the rigidity of a part of the outer ring equivalent member. Therefore, it is possible to reduce the weight of the outer ring equivalent member and, moreover, the rolling bearing unit incorporating the outer ring equivalent member while ensuring the strength of the outer ring equivalent member.

Preferably, when carrying out the present invention, as described in claim 3, 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. Use what you have. Then, each of the outer ring raceways and each of the inner ring raceways is divided into a plurality of rows, and a plurality of rolling elements are provided for each row. A pair of cages are provided in a state where they are rotatably held while being arranged at equal intervals in the circumferential direction. In addition, a pair of revolution speed detection sensors for detecting the revolution speed of the rolling elements in each row are arranged so that each detection portion faces the peripheral portion of each outer ring raceway on the outer peripheral surface of the outer ring equivalent member. Provide in the state. Then, the computing unit 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.
In this case, preferably, as described in claim 4, a ball is used as each rolling element, and a double-row angular outer ring raceway formed on the inner peripheral surface of the outer ring that does not rotate during use and a rotation during use. A contact angle of the back combination type is imparted to a plurality of balls each provided between the inner ring raceway and the double row angular type inner ring raceway formed on the outer peripheral surface of the inner ring equivalent member.

By adopting such a configuration, a rolling bearing unit that supports a wheel on a general independent suspension for a passenger car detects the revolution speed of a pair of rolling elements with different contact angle directions. Thus, the loads (radial load and axial load) applied between the outer ring equivalent member and the inner ring equivalent member constituting the rolling bearing unit can be accurately obtained. That is, when a load is applied to a rolling bearing unit such as a double-row angular ball bearing, the contact angle of the rolling elements (balls) in each row changes, and the revolution speed of the rolling elements in each row 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.
In addition, even in a single row rolling bearing unit such as a semi-floating suspension system, which is used for a non-independent suspension type suspension, if the contact angle is given to each rolling element, the change in the contact angle will be described. It is possible to determine the load applied to the single row rolling bearing unit based on the fluctuations in the revolution speed of each of the rolling elements. However, in this case, it is difficult to ensure measurement accuracy as compared with the case of a rolling bearing unit such as the double-row angular ball bearing.

  Preferably, as described in claims 5 and 6, a part of the outer ring equivalent member is provided on a detection surface of a rotation speed detecting encoder provided concentrically with the inner ring equivalent member on a part of the inner ring equivalent member. The rotation speed of the inner ring equivalent member can be detected by making the detection part of the rotation speed detection sensor supported by In this case, the rotational speed detection encoder is supported on the end of the inner ring equivalent member, and the rotational speed detection sensor is supported on the end of the outer ring equivalent member via a cover or the like. Accordingly, it is not necessary to form a through hole such as a mounting hole in the outer ring equivalent member in order to provide this rotational speed detection sensor.

And the computing unit is based on the ratio of the revolution speed of the rolling elements of one row and the revolution speed of the rolling elements of the other row and the rotational speed of the inner ring equivalent member, and the outer ring equivalent member and the above A radial load applied to the inner ring equivalent member is calculated (in the case of the invention described in claim 5). Alternatively, based on the ratio 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 rotational speed of the inner ring equivalent member, the outer ring equivalent member and the inner ring equivalent member The axial load applied between the two is calculated (in the case of the invention described in claim 6).
If comprised in this way, the load (radial load and axial load) applied to a rolling bearing unit can be calculated | required correctly irrespective of the fluctuation | variation of the rotational speed of the said inner ring | wheel equivalent member. If the axial load is calculated based on the ratio of the revolution speeds of the rolling elements in a pair of rows (in the case of the invention described in claim 7), this can be achieved without obtaining the rotational speed of the inner ring equivalent member. The axial load can be obtained accurately regardless of the rotational speed change.

  FIG. 1 shows an embodiment of the present invention. In this embodiment, the loads (radial load and axial load) applied to the rolling bearing unit for supporting the driving wheels of the automobile (the rear wheel of the FR vehicle, the RR vehicle, the MR vehicle, the front wheel of the FF vehicle, and all the wheels of the 4WD vehicle). ) Is measured when the present invention is applied to a load measuring device for a rolling bearing unit. A hub 2b for coupling and fixing the wheels is supported on the inner diameter side of the outer ring 1 supported by the suspension device. The hub 2b includes a hub main body 4a having a rotation side flange 3 for fixing a wheel at an outer end portion thereof, and an inner ring 6 fitted on the inner end portion of the hub main body 4a.

  A spline hole 27 for inserting a spline shaft attached to a constant velocity joint (not shown) is formed at the center of the hub body 4b. The inner end surface of the inner ring 6 is in contact with the outer end surface of the housing of the constant velocity joint in a state where the hub 2b is coupled and fixed to the constant velocity joint, thereby preventing the inner ring 6 from coming off from the hub body 4a.

Between the double-row angular inner ring raceways 8, 8 formed on the outer peripheral surface of the hub 2b as described above, and the double-row angular outer ring raceways 7, 7 formed on the inner peripheral surface of the outer ring 1, respectively. The rolling elements (balls) 9a and 9b are divided into double rows (two rows), and a plurality of rolling elements (balls) are provided for each row. These rolling elements 9a and 9b are provided so as to be freely rollable in a state of being arranged at equal intervals in the circumferential direction by retainers 28a and 28b, respectively. With this configuration, the hub 2b is rotatably supported on the inner diameter side of the outer ring 1. In this state, the rolling elements 9a and 9b in each row are provided with contact angles α _a and α _b (see FIG. 5) in opposite directions and of the same magnitude, so Configures an angular ball bearing. Sufficient preload is applied to the rolling elements 9a and 9b in each row so as not to be lost due to the axial load applied during use. When such a rolling bearing unit is used, the outer ring 1 is supported and fixed to a suspension device, and a braking disk and a wheel of a wheel are supported and fixed to the rotation side flange 3 of the hub 2.

  Further, the peripheral portions of the rolling elements 9a and 9b in each row at two positions (only one position is shown in FIG. 1) separated in the axial direction (left and right direction in FIG. 1) on the outer peripheral surface of the outer ring 1, that is, A revolution speed detecting sensor 23 is provided around the outer ring raceways 7 and 7. This revolution speed detecting sensor 23 is constructed by incorporating a magnetic detecting element such as a Hall element, MR element or the like that changes its characteristics in accordance with the strength of magnetic flux, and each detecting portion is provided on the outer peripheral surface of the outer ring 1. It is installed in a state of being opposed (contacted) to the outer peripheral surface of the outer ring 1. In this state, the revolution speed detecting sensor 23 detects a change in magnetic characteristics accompanying the passage of the rolling elements 9a and 9b via the outer ring 1. An arithmetic unit (not shown) that receives the signal from the revolution speed detecting sensor 23 calculates the revolution speed of each of the rolling elements 9a and 9b based on this signal, and further, based on this revolution speed, the outer ring. 1 and a load applied between the hub 2b. The operation when calculating the revolution speed and further calculating the load is the same as in the case of the above-described prior invention.

  In order to calculate the revolution speed of each of the rolling elements 9a and 9b based on the signal of the revolution speed detection sensor 23, there are a method based on the frequency of this signal and a method based on the period. It is preferable to adopt. The reason for this is that the revolution speed can be obtained only every predetermined time when it is determined by frequency, whereas in the case of the method based on the period, the detection unit of the revolution speed detection sensor 23 is set to each of the above. This is because the revolution speed is obtained every time the rolling elements 9a and 9b pass. That is, if the revolution speed is calculated based on the period, the revolution speed can be obtained in a shorter time (almost in real time), and the control for running stability of the vehicle can be effectively performed. In this embodiment, the rolling elements 9a and 9b are held at equal intervals in the circumferential direction by the cages 28a and 28b, so that the revolution speed calculation based on the period can be performed with high accuracy.

  As described above, the load measuring device of the rolling bearing unit of the present embodiment forms through holes such as mounting holes in the outer ring 1 in order to detect the revolution speeds of the rolling elements 9a and 9b. There is no need to reduce some rigidity. For this reason, while ensuring the strength of the outer ring 1, it is possible to reduce the weight of the outer ring 1 and the rolling bearing unit incorporating the outer ring 1. For this reason, the unsprung load of the automobile in which the rolling bearing unit having the load measuring function is assembled can be reduced, and the driving performance of the automobile can be improved.

1 is a schematic cross-sectional view showing an embodiment of the present invention. 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, 2b Hub 3, 3a Rotation side flange 4, 4a 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 Sensor rotor 14 Cover 15, 15a Rotational speed detection sensor 16 Knuckle 17 Fixed flange 18 Bolt 19 Screw hole 20 Load sensor 21 Sensor unit 22 Detector 23, 23a, 23b Revolution speed detection sensor 24a, 24b Retainer 25a, 25b Revolution speed Encoder for detection 26 Encoder for rotational speed detection 27 Spline hole 28a, 28b Cage

Claims (7)

  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 detection sensor for detecting the revolution speed of each of the rolling elements, and the revolution speed detection sensor. A computing unit that calculates a load applied between the outer ring equivalent member and the inner ring equivalent member based on a detection signal, wherein each of the rolling elements is made of a magnetic material, and the revolution speed detection sensor is the outer ring A load measuring device for a rolling bearing unit, which is installed on the outer peripheral surface of an equivalent member and detects the revolution speed by detecting a change in magnetic characteristics accompanying the passage of each rolling element through the outer ring equivalent member. .   The load measuring device for a rolling bearing unit according to claim 1, wherein each rolling element is magnetized.   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 element has a double row between each outer ring raceway and each inner ring raceway. In each of the rows, a plurality of rows are arranged at equal intervals in the circumferential direction by a pair of cages in a state in which the directions of contact angles are reversed between the rows. A pair of revolution speed detection sensors for detecting the revolution speed of the rolling elements in each row are respectively provided on the outer peripheral surface of the outer ring equivalent member. The arithmetic unit is provided between the outer ring equivalent member and the inner ring equivalent member based on a detection signal sent from each revolution speed detection sensor. The load according to any one of claims 1 to 2, which calculates a load to be applied. Load measuring device for a rolling bearing unit described.   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 The load measuring device for a 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 contact angle of a rear combination type.   A detection portion of a rotation speed detection sensor supported by a part of the outer ring equivalent member is made to face a detection surface of the rotation speed detection encoder provided concentrically with the inner ring equivalent member on a part of the inner ring equivalent member. Thus, the rotational speed of the inner ring equivalent member can be detected freely, and the computing unit calculates 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. The rolling bearing unit load measuring device according to claim 4, wherein a radial load applied between the outer ring equivalent member and the inner ring equivalent member is calculated based on a ratio of   A detection portion of a rotation speed detection sensor supported by a part of the outer ring equivalent member is made to face a detection surface of the rotation speed detection encoder provided concentrically with the inner ring equivalent member on a part of the inner ring equivalent member. Thus, the rotational speed of the inner ring equivalent member can be detected freely, and the calculator calculates the 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 rotational speed of the inner ring equivalent member. The load measuring device for a rolling bearing unit according to claim 4, wherein an axial load applied between the outer ring equivalent member and the inner ring equivalent member is calculated based on the ratio.   The computing unit 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. 4. A load measuring device for a rolling bearing unit described in 4.

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