JP2005214744A - Load-measuring device for rolling bearing unit for supporting wheel, and running stabilizer for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure running stability of a vehicle, by accurately finding a load or the like being applied to a rolling bearing unit for supporting a wheel. <P>SOLUTION: When air pressure of a tire, constituting a wheel, varies from a predetermined value, the value of the load or the like found on the basis of a detected signal, is corrected to the value of the load or the like which is actually applied, corresponding to the amount of the variation of the air pressure. On the basis of the value corrected in this way, control for ensuring the running stability of the vehicle is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  A load measuring device for a wheel bearing rolling bearing unit that is an object of the present invention is, for example, a load applied to a rolling bearing unit for supporting a wheel of a vehicle such as an automobile (one or both of a radial load and an axial load). ) Is measured and used to ensure the running stability of the vehicle. In addition, a vehicle travel stabilization device that is an object of the present invention includes an anti-lock brake system (ABS), a traction control system (TCS), and a vehicle stability control that are used to ensure the travel stability of the vehicle. The present invention has been invented to ensure a higher degree of running stability with respect to improvements in a vehicle running stabilization device such as a system (VCS).

  For example, an automobile wheel is rotatably supported by a double row angular rolling bearing unit with respect to a suspension device. Also, in order to ensure the running stability of automobiles, vehicle running stabilization devices such as anti-lock brake system (ABS), traction control system (TCS), and vehicle stability control system (VSC) are used. Yes. In order to control such a travel stabilization device for a vehicle, signals such as the rotational speed of the wheel 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 rotation side flange 3 for fixing the wheel at its outer end (outside in the axial direction is outside in the width direction when assembled to the vehicle, left side in FIGS. 5 to 8, 11 and 14). And the inner end of the hub body 4 (the inner side in the axial direction is the end that is the center side in the width direction when assembled to the vehicle, and is the left side in FIGS. 5-8, 11 and 14) And an inner ring 6 that is externally fitted and held down by a nut 5. 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 radial load applied to the rolling bearing unit can be obtained based on the detection signal of the displacement sensor 11. In the conventional structure shown in FIG. 5, in addition to the radial load applied to the rolling bearing unit, the rotational speed of the hub 2 can also be detected by the rotational speed detection sensor 21 and the rotational speed detection encoder 24.

  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. 6 shows a rolling bearing unit with a load measuring device described in Patent Document 2 for measuring an axial load. 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 14 is fixed to the outer peripheral surface of the outer ring 1a for supporting and fixing the outer ring 1a to a knuckle 13 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 17 is attached to a portion surrounding the screw hole 16 for screwing a bolt 15 for connecting the fixed side flange 14 to the knuckle 13 at a plurality of locations on the inner side surface of the fixed side flange 14. Has been established. Each load sensor 17 is sandwiched between the outer side surface of the knuckle 13 and the inner side surface of the fixed flange 14 while the outer ring 1a is supported and fixed to the knuckle 13.

  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 13, the outer surface of the knuckle 13 and the fixed side flange 14 The inner surface strongly presses each load sensor 17 from both sides in the axial direction. Therefore, the axial load applied between the wheel and the knuckle 13 can be obtained by summing up the measured values of the load sensors 17. 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. 5 described above, the radial 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 amount of displacement in the radial direction is small, it is necessary to use a highly accurate displacement sensor 11 in order to obtain the radial 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. 6 described above, it is necessary to provide the same number of load sensors 17 as the bolts 15 for supporting and fixing the outer ring 1 a to the knuckle 13. For this reason, coupled with the fact that the load sensor 17 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 for measuring a radial load or an axial load applied to the bearing was made (Japanese Patent Application No. 2004-7655). FIG. 7 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 18 is inserted into the mounting hole 10a formed in the portion between the double-row outer ring raceways 7 and 7 at the axially intermediate portion of the outer ring 1 which is an outer ring equivalent member and is a stationary ring. The tip 19 of the sensor unit 18 is projected from the inner peripheral surface of the outer ring 1. The distal end portion 19 is provided with a pair of revolution speed detection sensors 20 a and 20 b and a single rotation speed detection sensor 21.

  And the detection part of each revolution speed detection sensor 20a, 20b of these is provided in each retainer 22a, 22b which hold | maintained each rolling element 9a, 9b arrange | positioned in a double row rotatably, The revolution speed detection The revolving speeds of the rolling elements 9a and 9b are made freely detectable by being close to and opposed to the encoders 23a and 23b. Further, the detection portion of the rotation speed detection sensor 21 is made close to and opposed to the rotation speed detection encoder 24 that is an inner ring equivalent member and is externally fitted and fixed to an intermediate portion of the hub 2 that is a rotation wheel. The rotation speed can be detected freely. According to the load measuring device for a rolling bearing unit according to the prior invention having such a configuration, a load (one or both of a radial load and an axial load) applied between the outer ring 1 and the hub 2 is obtained. It is done.

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) is configured to output the outer ring 1 and the hub 2 based on detection signals sent from the sensors 20a, 20b, and 21. 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 20a and 20b, 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 21. The axial load is obtained by calculating the difference between the revolution speeds of the rolling elements 9a and 9b in the respective rows detected by the revolution speed detection sensors 20a and 20b, and this difference and the rotation speed detection sensor 21 detect the difference. Calculation is based on the ratio to the rotational speed of the hub 2. This point will be described with reference to FIGS. 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. 8 schematically shows the rolling bearing unit for supporting the wheel shown in FIG. 7 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. In addition, a radial load Fz is applied to the rolling bearing unit from the road surface side as a reaction against the weight of the vehicle body and the like during use. 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 the case of this example, since the hub 2 rotates and the outer ring 1 does not rotate, specifically, with respect to the radial load Fz, as the radial load Fz increases, as shown in FIG. (ratio epsilon _a between the rotational speed n _i of the hub 2, ε _b) columns of the revolution speed n _c is delayed. Further, with respect to the axial load Fy, as shown in FIG. 10, the rolling elements 9a of the column that supports the axial load Fy, 9a revolution speed n _c (the ratio between the rotation speed n _i of the hub 2 epsilon _a) of The speed is increased, and the revolution speed n _c (the ratio ε _b of the rotational speed ni of the hub 2) of the rolling elements 9b, 9b in the row not supporting the axial load Fy is decreased. Accordingly, the rolling elements 9a of each row, based on the revolution speed n _c of 9b, 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 view of such circumstances, in the prior invention, as described above, when the radial load Fz is obtained, the revolution speed n of each rolling element 9a, 9b detected by each revolution speed detection sensor 20a, 20b is detected. By determining the sum of _c , the influence of the axial load Fy is reduced. Further, when obtaining the axial load Fy is the rolling elements 9a of each column, by obtaining a difference of the revolution speed n _c of 9b, are reduced influence of the radial load Fz. Furthermore, in any case, the radial load Fz or the axial load Fy is based on the ratios ε _a and ε _b between the sum or difference and the rotational speed _{ni of the} hub 2 detected by the rotational speed detection sensor 21. by calculating the, excludes the influence of the rotational speed n _i of the hub 2. Incidentally, the axial load Fy, when calculating on the basis of the ratio of the revolution speed n _c of the rolling elements 9a, 9b of each column, 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 20a and 20b. This method is described in detail in the above-mentioned Japanese Patent Application No. 2004-7655, and is not related to the gist of the present invention, so detailed description thereof is omitted.

  The load measured (calculated) by the load measuring device of the rolling bearing unit as described above is equivalent to the load generated on the contact surface between the wheel (the tire constituting the wheel) and the road surface. Therefore, if the control for stabilizing the running state of the vehicle is performed based on the measured load, it is possible to prevent the vehicle from becoming unstable and to enable feedforward control. Advanced control to ensure stability is possible. However, when the air pressure of the tire constituting the wheel fluctuates, there is a possibility that a difference occurs between the measured load and the actually applied load. Therefore, it is preferable to correct such a difference in order to perform higher-level control.

That is, the rolling bearing unit such as shown in Figure 7 described above, radial load Fz and the axial load Fy is in the case of action each row of the rolling elements 9a, the revolution speed of 9b (and the rotational speed n _i of the hub 2 The ratios ε _a and ε _b can be expressed by the following equations (2) and (3), respectively, by using the influence coefficients k _ya , _kyb , k _za , and k _zb .
ε _a = k _ya · Fy + k _za · Fz −−− (2)
ε _b = k _yb · Fy + k _zb · Fz −−− (3)
The slopes (tilts) of the solid lines A, C and broken lines B, D shown in FIGS. 9 and 10 are the influence coefficients k _ya , k _yb , k _za , k _zb . Here, when the radial load Fz and the axial load Fy are solved from the above (2) and (3), the following equations (4) and (5) are obtained.
_{Fz = - (k ya · ε} b -k yb · ε a) / (k yb · k za -k zb · k ya) --- (4) Fy = (k za · ε b -k zb · ε a ) / (K _yb · k _za −k _zb · k _ya ) −−− (5)

As apparent from these equations (4) and (5), if the revolution speeds ε _a and ε _b of the rolling elements 9a and 9b in each row are detected, the influence coefficients k _ya , k _yb , k _za and k _zb are used. From the above equations (4) and (5), the radial load Fz and the axial load Fy can be obtained. However, when the influence coefficients k _ya , k _yb , k _za , and k _zb vary (when the slopes of solid lines A, C, broken lines B, and D in FIGS. 9 to 10 change), these fluctuations are considered. Otherwise, there is a difference between the calculated loads Fz and Fy and the actually applied loads Fz and Fy. Such variations in the influence coefficients k _ya , k _yb , k _za , and k _zb are caused by differences in the positions (load application points) where the radial load Fz and the axial load Fy are applied.

As indicated by the arrows in FIG. 8, when the radial load Fz is applied to the central portion of both rolling elements 9a and 9b, and the axial load Fy is applied to the central portion of the hub 2 of the rolling bearing unit, these radial loads are applied. As described above, the load Fz and the axial load Fy and the revolution speeds ε _a and ε _b of the rolling elements 9a and 9b in each row have the relationship shown in FIGS. In contrast, as indicated by arrows in FIG. 11, the axial load Fy is removed from the center of the hub 2 of the rolling bearing unit at a position where the radial load Fz deviates from the vicinity of the center of both rolling elements 9a and 9b. In the case where each is applied to a position that is out of position, the radial load Fz and the axial load Fy and the revolution speeds ε _a and ε _b of the rolling elements 9a and 9b in each row have the relationship shown in FIGS.

As apparent from comparing FIGS. 12 and 13 with FIGS. 9 and 10, the influence coefficients k _ya , k _yb , k are changed by changing the positions to which the radial load Fz and the axial load Fy are applied. _It can be seen that _za and k _zb fluctuate (the solid lines i and i ′ shown in FIGS. 9, 10, 12 and 13 are different from each other, and the slopes of the solid lines c and b are broken lines b and b). When such influence coefficients k _ya , _kyb , k _za , and k _zb fluctuate, these fluctuations are not taken into account (for example, the influence coefficients k _ya , _kyb , k _za , and k _zb are left as they are). When the radial load Fz and the axial load Fy are calculated, there is a difference between the calculated loads Fz and Fy and the actually applied loads Fz and Fy.

  On the other hand, in the case of a rolling bearing unit for supporting a wheel including wheels, the position to which the radial load Fz and the axial load Fy are applied differs depending on the structure of the suspension device supporting the wheel, the size of the tire constituting the wheel, and the type of the tire. At the same time, the tire moves as the air pressure changes. That is, FIG. 14A shows a case where the tire 25 has a predetermined air pressure, and FIG. 14B shows a case where the air pressure is smaller than the predetermined value (air is released). When the air pressure becomes smaller than a predetermined value, the distance A between the center axis α of the wheel bearing rolling bearing unit and the road surface 26 becomes shorter. At the same time, the position X where the radial load Fz and the axial load Fy are applied (road surface contact center) X is axially based on the magnitude and direction of the axial load Fy acting on the contact surface between the tire 25 and the road surface 26. Displace (displace). Although not shown, the position where the radial load Fz and the axial load Fy are applied and the center of the rolling bearing unit for supporting the wheel also depend on the structure of the suspension device for supporting the wheel and the size and type of the tire constituting the wheel. The distance between the shaft and the road surface is different.

Regarding the structure of the suspension device and the type of tire, the structure and type can be grasped in advance. Therefore, if the influence coefficients k _ya , k _yb , k _za , and k _zb according to the structure and type are obtained in advance (given as initial values), the calculated loads Fz and Fy are actually There is no difference between the applied loads Fz and Fy. On the other hand, the fluctuation time and quantity of the tire 25 cannot be predicted. For this reason, when the air pressure of the tire 25 varies, if the influence coefficients k _ya , k _yb , k _za , and k _zb are left as they are, the calculated loads Fz and Fy and the loads Fz and Fy that are actually applied are calculated. The difference remains. It is not preferable to control the vehicle travel stabilization device such as ABS, TCS, VSC or the like with such a difference in order to ensure the stability of vehicle operation at a high level.
Note that the difference between the calculated value and the actual value based on the air pressure variation is not limited to the case where the loads Fz and Fy are calculated. For example, even when calculating the moment applied to the wheel support rolling bearing unit or the rotational speed of the rotating wheel, there is a possibility that a difference is generated based on the fluctuation of the air pressure.

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

  The load measuring device for a wheel support rolling bearing unit and the vehicle running stabilization device of the present invention are calculated in consideration of the above-described circumstances even when the tire air pressure constituting the wheel fluctuates. Invented in order to prevent the difference between the actual load value and the actual applied load value and to ensure a higher level of vehicle running stability.

Among the load measuring device for a wheel support rolling bearing unit and the vehicle running stabilization device of the present invention, the load measuring device for a wheel support rolling bearing unit according to claim 1 includes an outer ring equivalent member, an inner ring equivalent member, And a plurality of rolling elements, a measuring means, and a calculator.
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.
The rolling elements are provided between the inner ring raceway and the outer ring raceway.
The measuring means is for measuring a state quantity that changes based on a load acting on the inner ring equivalent member and the outer ring equivalent member.
The computing unit calculates the load based on a detection signal sent from the measuring means.
And a wheel is supported and fixed to the rotating wheel which rotates at the time of use among the said outer ring equivalent member and the said inner ring equivalent member.
In particular, in the load measuring device for a wheel bearing rolling bearing unit according to the present invention, the computing unit detects the detection signal when the air pressure of a tire constituting the wheel fluctuates from a predetermined value (reference value). A function of correcting the load value obtained on the basis of the load value to an actually applied load value according to the fluctuation amount of the air pressure is provided.

According to a sixth aspect of the present invention, there is provided a vehicular running stabilization device that is calculated by a load measuring device incorporated in a wheel-supporting rolling bearing unit, and an inner ring equivalent member and an outer ring equivalent member that constitute the wheel support rolling bearing unit. And a moment generated with respect to a perpendicular line perpendicular to the central axis of the inner ring equivalent member and outer ring equivalent member acting on the inner ring equivalent member and outer ring equivalent member (both these members as described below). The control is performed to ensure the running stability of the vehicle on the basis of at least the load among the moments acting in the direction of shifting the center axis of the motor) and the rotational speed of the rotating wheel rotating during use. is there.
In particular, in the vehicle travel stabilization device of the present invention, the load measuring device is a load measuring device for the above-described wheel-supporting rolling bearing unit.

  According to the load measuring device for a wheel bearing rolling bearing unit and the vehicle running stabilization device of the present invention configured as described above, even if the air pressure of the tire constituting the wheel fluctuates, the detection signal sent from the measuring means Thus, there is no difference between the load value calculated on the basis of the load value and the load value actually applied, and the stability of the operation of the vehicle can be secured at a high level.

Preferably, when carrying out the present invention, as described in claim 2, the computing unit operates on the inner ring equivalent member and the outer ring equivalent member based on the detection signal sent from the measuring means, and the inner ring equivalent member and Moment generated with respect to a perpendicular line perpendicular to the central axis of the outer ring equivalent member (a moment acting in a direction that causes the central axis of the inner ring equivalent member to deviate from the central axis of the outer ring equivalent member. At least one of a moment based on a force acting in a direction perpendicular to the angle and a moment generated around the perpendicular) and a rotational speed of a rotating wheel that rotates during use is calculated. It shall be equipped with functions. At the same time, when the air pressure of the tire constituting the wheel fluctuates from a predetermined value, at least one of the moment and the rotation speed calculated based on the detection signal is set to the air pressure. It is assumed that a function for correcting the moment to be actually applied or the value of the actual rotational speed according to the amount of fluctuation is provided.
With this configuration, it is possible to ensure the stability of the vehicle operation at a high level so that there is no difference between the calculated value and the actual value regarding the moment and the rotational speed as well as the load.

In addition, when correcting the calculated value such as a load to an actual value, preferably, as described in claim 3, the tire air pressure fluctuation amount obtained in advance and the detection sent from the measuring means are detected. The value obtained based on the detection signal is corrected to the actual value corresponding to the air pressure from the relationship between the value obtained based on the signal and the deviation amount between the actual value.
For example, when considering the load, as described above, when the tire air pressure fluctuates, the position (load application point) to which the radial load Fz and the axial load Fy are applied is displaced (shifted) in accordance with the fluctuation amount of the air pressure. ). Based on the displacement (displacement) of the load application point, the influence coefficients k _ya , k _yb , k _za , and k _{zb in} the above-described equations (4) and (5) vary. Accordingly, the influence coefficients k _ya , k _yb , k _za , k _zb corresponding to the air pressure are obtained in advance from the relationship between the fluctuation amount of the air pressure and the displacement amount (deviation amount) of the position of the load application point. If the loads Fz and Fy are obtained based on the influence coefficients k _ya , _kyb , k _za , and k _zb according to the air pressure when the air pressure fluctuates, the load that actually adds the values of the calculated loads Fz and Fy The values can be corrected to Fz and Fy.

The relationship between the amount of variation in the tire air pressure and the amount of displacement (displacement) of the load application point, and the influence coefficients k _ya , _kyb , k _za , and k _zb corresponding to the amount of displacement are designed in advance. Alternatively, it is obtained experimentally by computer simulation or the like, and is incorporated as a mathematical formula or a map or the like in software installed in a microcomputer constituting the arithmetic unit. According to this configuration, when the tire air pressure changes, the loads Fz and Fy can be obtained in a state in which the loads Fz and Fy are corrected to values corresponding to the air pressure by referring to the formula or the map. . The fluctuation of the tire air pressure can be obtained from an air pressure measuring sensor or the like incorporated in the tire valve or the like. Then, if the above-described correction corresponding to the air pressure is performed as necessary based on the value of the tire air pressure obtained from such an air pressure measurement sensor, the loads Fz and Fy are always accurately calculated (calculated. (There is no difference between the actual value and the actual value).

Preferably, when carrying out the present invention, preferably, as described in claim 4, a double row outer ring raceway formed on the inner peripheral surface of the outer ring equivalent member and a double row formed on the outer peripheral surface of the inner ring equivalent member. A plurality of rolling elements are provided for each row between the inner ring raceways of the rows with contact angles in different directions between the rows, and the contact angles change based on the load. The state quantity to be used. The measuring means includes a pair of revolution speed detection sensors for detecting the revolution speed of the rolling elements in each row. Further, the computing unit applies a load applied between the outer ring equivalent member and the inner ring equivalent member based on a detection signal sent from the both revolution speed detection sensors and representing the revolution speed of the rolling elements in each row. calculate.
By adopting such a configuration, the load can be accurately measured regardless of fluctuations in tire air pressure, with a structure that can be configured at low cost without using an expensive displacement sensor or load sensor.

Further, when carrying out the invention according to claim 4 as described above, preferably, as described in claim 5, the rotational speed of the rotating wheel rotating during use is detected among the outer ring equivalent member and the inner ring equivalent member. A rotation speed detecting sensor. The computing unit, based on the detection signal representing the rotational speed of the rotating wheel fed from the rotational speed detection sensor and the detection signal representing the revolution speed of the rolling elements in each row, and the outer ring equivalent member and the above The load applied to the inner ring equivalent member is calculated.
By adopting such a configuration, the load can be accurately obtained even in a situation where the rotational speed of the rotating wheel varies.

Preferably, when the invention according to claim 6 is carried out, as described in claim 7, the control for ensuring the running stability of the vehicle is performed with at least a load among a load, a moment and a rotational speed. And based on the vehicle speed and the steering angle and steering force of the steering wheel obtained from the power steering device. In this case, as described in claim 8, the vehicle speed may be obtained from the rotational speed.
By adopting such a configuration, the above-described control is performed based on a lot of information, so that the running stability of the vehicle can be further improved.

Preferably, at the time of the control for ensuring the running stability of the vehicle, at least one of the brake devices attached to each wheel regardless of whether or not the brake pedal is operated. At least one of a brake control for applying a braking force to the wheel by each brake device, a control for adjusting the assist force of the power steering device, and a control for adjusting the gear ratio is performed.
Such brake control and control for adjusting the assist force are performed as follows, for example. In other words, a typical state that requires control to ensure driving stability is the same as in the case of oversteer (spin) where the direction of the vehicle changes more than the steering wheel operation amount. There is no understeer (drift out).

  When brake control for correcting (or preventing) oversteer is performed, a relatively large braking force is generated in the brake device attached to the wheel on the front side in the traveling direction and on the outer side in the turning direction. As a result, a force in the direction opposite to the direction in which the vehicle is turned is applied to the vehicle from the wheel on the front side in the traveling direction and on the outer side in the turning direction, so that the oversteer state is eliminated (or prevented), and the vehicle is moved to the steering wheel. The course is changed by an amount corresponding to the rudder angle given to the wheel based on the operation. In addition, when performing control for adjusting the assist force or gear ratio for correcting (or preventing) the oversteer, the steering force required for the driver to operate the steering wheel by reducing the assist force is reduced. Even when the steering wheel is steered by increasing the gear ratio or decreasing the gear ratio, it is difficult to generate the steering angle of the wheel so that the steering angle inward in the turning direction is not further increased. Furthermore, in order to quickly recover from the oversteer state, the assist force is applied in the direction opposite to the direction in which the steering wheel is operated (a negative assist force is applied) or the steering angle starts in the reverse direction. At the same time, by increasing the gear ratio so that the steering of the steering wheel is transmitted sensitively to the steering angle of the wheel, it is easy to steer the wheel to the outside in the turning direction (so-called counter steer is easily applied). ). As a result, the oversteer state is eliminated (or prevented), and the running stability of the vehicle is maintained.

  On the other hand, when brake control for correcting (or preventing) the understeer is performed, a relatively large braking force is generated in the brake device attached to the wheel on the inner side in the turning direction on the rear side in the traveling direction, and the front of the wheel is moved forward. The force that tries to move to is smaller than the force that tries to move ahead of the other wheels. As a result, a force in a direction of making a large turn is applied by the vehicle, the understeer state is eliminated (or prevented), and the vehicle corresponds to the rudder angle applied to the wheel based on the operation of the steering wheel. Change course. Also, when performing control for adjusting the assist force and gear ratio for correcting (or preventing) the understeer, the assist force is reduced to increase the steering force required for the driver to operate the steering wheel. In other words, even if the gear ratio is reduced and the steering wheel is steered, the steering angle of the wheel is less likely to be generated, so that the steering angle (cut) inward in the turning direction is not further increased. As a result, the understeer state is eliminated (or prevented), and the running stability of the vehicle can be ensured.

  FIG. 1 shows a first embodiment of the present invention corresponding to claims 1 to 5. The feature of the present invention is to realize a load measuring device for a wheel bearing rolling bearing unit that can accurately obtain the load F applied to the rolling bearing unit even when the air pressure P of the tire 25 (see FIG. 14) constituting the wheel fluctuates. Therefore, correction is made to eliminate an error associated with the fluctuation of the air pressure P. The correction performed when the tire air pressure P fluctuates is based on the procedure shown in the flowchart of FIG. 1 and is incorporated in advance in software installed in a microcomputer constituting a computing unit (not shown). Alternatively, it is performed while referring to a map or the like. Since the structure of the load measuring device itself of the wheel bearing rolling bearing unit is the same as the structure of the prior invention shown in FIG. 7 described above, the redundant description will be omitted, and the following description will be made on the above correction. To do.

  In the case of the present embodiment, the calculator calculates the load F based on the detection signals sent from the pair of revolution speed detection sensors 20a and 20b and the rotational speed detection sensor 21 (see FIG. 7) which are measuring means. Is calculated. Such a load F is obtained separately in an XYZ orthogonal coordinate system as necessary. For example, in the assembled state to the vehicle, a load (axial load) Fy applied in the lateral direction (Y-axis direction) of the vehicle, a load Fx applied in the front-rear direction (X-axis direction) of the vehicle, and the vertical direction of the vehicle The load (radial load) Fx applied in the (Z-axis direction) is obtained separately. Further, together with such a load F, the central axis of the outer ring 1 and the hub 2 acting on the hub 2 which is an inner ring equivalent member and a rotating wheel and the outer ring 1 which is an outer ring equivalent member and a stationary ring (see FIG. 7). A moment M (Mz) generated with respect to a perpendicular (Z axis) perpendicular to the (Y axis) and the rotational speed w of the hub 2 are calculated. The load F and the moment M are state quantities that change based on the load F and the moment M acting between the hub 2 and the outer ring 1, that is, rolling elements 9a and 9b arranged in double rows (see FIG. 7). It calculates based on the contact angle. More specifically, as described in the structure of the prior invention shown in FIG. 7 described above, the revolution speed of the rolling elements 9a and 9b in each row, which changes according to the change in the contact angle, The load F and the moment M are calculated from the revolution speeds (sum, difference and ratio) of the rolling elements 9a and 9b in each row detected by the speed detection sensors 20a and 20b.

  The rotational speed w of the hub 2 is based on the detection signal sent from the rotational speed detection sensor 21 or the revolutions of the rolling elements 9a and 9b detected by the both revolution speed detection sensors 20a and 20b. It calculates based on the detection signal showing speed. The rotational speed w of the hub 2 calculated in this way is also used for calculating the load F as necessary. In the case of this example, an air pressure measuring sensor for detecting the value of the air pressure P of the tire 25 is provided on the valve of the tire 25 constituting the wheel. Then, a detection signal representing the value of the air pressure P of the tire 25 detected by the air pressure measuring sensor is sent to the computing unit by wireless communication. Then, based on the value of the tire air pressure P obtained from the air pressure measurement sensor, the values of the load F, moment M, and rotational speed w calculated as described above are corrected as necessary.

  The procedure for obtaining the load F, moment M and rotational speed w including such correction is as follows. First, in step 1, the load F, the moment M, the rotational speed w, and the air pressure P of the tire 25 are measured as described above. Next, in step 2, whether or not the air pressure P of the tire 25 is a predetermined value, that is, whether or not the air pressure P of the tire 25 is the target air pressure Pt (the measured air pressure P and the target air pressure Pt exceed a threshold value). Whether there is a difference). When it is determined that the air pressure P of the tire 25 is a predetermined value, that is, when it is determined that it is the target air pressure Pt (the difference is within the threshold range), the load measured in the step 1 is determined. F, moment M, and rotational speed w are sent as they are to the controller of the vehicle travel stabilization device such as ABS, TCS, VSC, etc. (step 4).

  On the other hand, if it is determined that the air pressure P of the tire 25 is not a predetermined value, that is, if it is determined that the air pressure P of the tire 25 is not the target air pressure Pt (the difference exceeds the threshold value), step 3 Thus, the values of the load F, moment M, and rotational speed w measured in step 1 are corrected according to the variation amount of the air pressure P of the tire 25, respectively. That is, as described above, a relational expression or map between the fluctuation amount of the air pressure P of the tire 25 and the influence coefficient corresponding to the fluctuation amount, which has been obtained in advance by design or experimentally by computer simulation or the like. Etc., the values of the load F, moment M, and rotational speed w are corrected to values corresponding to the air pressure P, respectively. Then, the load F ′, moment M ′, and rotational speed w ′ corrected to values corresponding to the air pressure P are sent to the controller of the vehicle travel stabilization device (step 4). Based on the load F (F ′), the moment M (M ′), and the rotational speed w (w ′) after such a procedure, if the vehicle running stabilization device is controlled, Stability can be secured at a high level.

  Next, FIG. 2 shows Embodiment 2 of the present invention corresponding to claims 1 to 9. In the case of the present embodiment, the vehicular travel stabilization device for ensuring the travel stability of the vehicle includes a VSC control for eliminating (or preventing) understeer and oversteer. In the case of this embodiment, at the time of control for eliminating (or preventing) such understeer and oversteer, at least one of the brake devices attached to each wheel regardless of whether or not the brake pedal is operated. The brake control for applying a braking force to the wheel is performed by the brake device. In the case of the present embodiment including such control, in step 1, the load F, the moment M, the rotational speed w, and the air pressure P of the tire 25 (see FIG. 14) are measured in the same manner as in the first embodiment. To do. At the same time, the vehicle speed (vehicle speed) V, the steering angle δ of the steering wheel constituting the power steering device, and the steering force Th applied to the steering wheel are also measured. The vehicle speed V may be calculated from the rotational speed w or may be obtained from another vehicle speed sensor or the like provided in a transmission or the like.

  Next, in step 2, it is determined whether or not the air pressure P of the tire 25 is a predetermined value. When it is determined that the air pressure P of the tire 25 is a predetermined value, the load F, moment M, and rotational speed w measured in step 1 are sent to step 4 described below as they are. On the other hand, if it is determined that the air pressure P of the tire 25 is not a predetermined value, in step 3, the values of the load F, moment M, and rotational speed w measured in step 1 are set as described above. As in Example 1, the load F ′, moment M ′, and rotational speed w ′ corresponding to the air pressure P are corrected.

  Next, in step 4, the load F, moment M, rotational speed w measured in step 1 or the load F ′, moment M ′, rotational speed w ′ corrected in step 3, and the step Based on the air pressure P of the tire 25, the vehicle speed V, the steering angle δ, and the steering force Th measured in step 1, it is determined whether or not to perform control for ensuring the running stability of the vehicle. For this reason, in this example, the actual yaw rate (turning moment) γ actually applied to the vehicle is calculated from the load F (F ′), the moment M (M ′), etc., and the vehicle speed V, the steering angle are calculated. A standard yaw rate γ ′ capable of realizing a stable running state under the vehicle speed V and the steering angle δ (no understeer or oversteer is generated) is calculated from δ, etc., and the actual yaw rate γ is within the range of the standard yaw rate γ ′. It is judged whether it is in.

  If the actual yaw rate γ is not within the range of the target yaw rate γ ′, it is determined that it is necessary to perform control for ensuring the running stability of the vehicle, and the vehicle is stabilized in subsequent step 5. A target yaw rate γt necessary for maintaining a stable state is obtained, and a target braking force Bft necessary for generating the target yaw rate γt is calculated. Next, in step 6, the braking force Bf is generated in the brake device, and in the subsequent step 7, it is determined whether or not the target braking force Bft is generated in the brake device. It is determined whether the target yaw rate γt is obtained based on the generated braking force Bf. As a result of such work, the actual yaw rate γ falls within the range of the standard yaw rate γ ′, and the running stability of the vehicle can be ensured (understeer and oversteer can be eliminated or prevented).

  Next, FIG. 3 shows Embodiment 3 of the present invention corresponding to claims 1-9. In the case of the present embodiment, control for adjusting the assist force of the power steering device is performed in the control for eliminating (or preventing) understeer and oversteer. That is, if it is determined in step 4 that it is necessary to perform control for ensuring the running stability of the vehicle, then in step 5, the target yaw rate γt necessary for stabilizing the vehicle is obtained, and this A target steering force Tht necessary for generating the target yaw rate γt is calculated. In step 6, the steering force Th is adjusted by adjusting the assist force applied to the steering hole of the power steering device. In step 7, it is determined whether or not the target steering force Tht is obtained. In subsequent step 8, the target steering force Tht is changed along with the change in the steering angle of the steering wheel based on the adjustment of the steering force Th. It is determined whether the yaw rate γt is obtained. Note that the gear ratio of the power steering device may be adjusted instead of the assist force adjustment or together with the assist force adjustment. Other configurations and operations are the same as those of the above-described second embodiment, and thus redundant description is omitted.

  Next, FIG. 4 shows Embodiment 4 of the present invention corresponding to claims 1 to 9. In the case of this embodiment, at the time of control for eliminating (or preventing) understeer and oversteer, at least one brake of the brake devices attached to each wheel regardless of whether or not the brake pedal is operated. A brake control for applying a braking force to the wheel is performed by the device, and a control for adjusting the assist force and the gear ratio of the power steering device is also performed. That is, in the case of the present embodiment, the brake control described in the second embodiment and the control for adjusting the assist force and the gear ratio described in the third embodiment are selected simultaneously or necessary. By doing so, the running stability of the vehicle is more sufficiently secured. Other configurations and operations are the same as those of the above-described second embodiment and the above-described third embodiment.

The flowchart which shows Example 1 of this invention. The flowchart which shows the same Example 2. FIG. 10 is a flowchart showing the third embodiment. 9 is a flowchart showing the fourth embodiment. Sectional drawing of a rolling bearing unit that incorporates a sensor for measuring radial load, which has been conventionally known. Sectional drawing of a rolling bearing unit that incorporates a sensor for measuring an axial load, which has been 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 a load is calculated | required by prior invention. Similarly, the diagram which shows the relationship between the ratio of the revolution speed of each row | line | column and the rotational speed of a hub, and radial load. Similarly, the diagram which shows the relationship between the ratio of the revolution speed of each row | line | column and the rotational speed of a hub, and an axial load. The figure similar to FIG. 8 which shows the state which the position to which a radial load and an axial load apply changes. The diagram which shows the relationship between the ratio of the revolution speed of each row | line | column and the rotational speed of a hub, and a radial load in the state shown in FIG. Similarly, the diagram which shows the relationship between the ratio of the revolution speed of each row | line | column and the rotational speed of a hub, and an axial load. Sectional drawing for demonstrating that the position where a load is added changes with the fluctuation | variation of the pneumatic pressure of a tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Outer ring 2, 2a Hub 3, 3a Rotation side flange 4 Hub main body 5 Nut 6 Inner ring 7 Outer ring raceway 8 Inner ring raceway 9a, 9b Rolling element 10 Mounting hole 11 Displacement sensor 12 Sensor ring 13 Knuckle 14 Fixed side flange 15 Bolt 16 Screw hole 17 Load sensor 18 Sensor unit 19 Tip 20a, 20b Revolution speed detection sensor 21 Rotational speed detection sensor 22a, 22b Cage 23a, 23b Revolution speed detection encoder 24 Rotational speed detection encoder 25 Tire 26 Road surface

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 between the raceway, a measuring means for measuring a state quantity that changes based on a load acting on the inner ring equivalent member and the outer ring equivalent member, and a detection sent from the measurement means A load measuring device for a wheel-supporting rolling bearing unit that includes a computing unit that calculates the load based on a signal, and that supports and fixes a wheel to a rotating wheel that rotates during use of the outer ring equivalent member and the inner ring equivalent member. In this case, when the air pressure of the tire that constitutes the wheel fluctuates from a predetermined value, the computing unit determines the load value obtained based on the detection signal in accordance with the air pressure fluctuation amount. Actually load measuring device of the wheel supporting rolling bearing unit, characterized in that has a function of correcting the value of the load applied.   The computing unit operates on the inner ring equivalent member and the outer ring equivalent member based on the detection signal sent from the measuring means, and the moment generated with respect to the perpendicular line perpendicular to the central axis of the inner ring equivalent member and the outer ring equivalent member, A function of calculating at least one of the rotational speeds of the rotating wheels that rotate, and the pressure that is obtained based on the detection signal when the air pressure of the tire that constitutes the wheel fluctuates from a predetermined value. The wheel according to claim 1, comprising a function of correcting at least one of a moment and a rotational speed to a moment actually applied or a value of an actual rotational speed in accordance with the fluctuation amount of the air pressure. Load measuring device for supporting rolling bearing unit.   Based on the relationship between the amount of variation in tire air pressure obtained in advance and the amount of deviation between the value obtained based on the detection signal sent from the measuring means and the actual value, the value obtained based on the detection signal is The load measuring device for a wheel bearing rolling bearing unit according to claim 1, wherein the load is corrected to an actual value corresponding to the air pressure.   Between the double row outer ring raceway formed on the inner peripheral surface of the outer ring equivalent member and the double row inner ring raceway formed on the outer peripheral surface of the inner ring equivalent member, a plurality of rolling elements for each row, Each row is provided with contact angles in directions different from each other, and the amount of state that changes based on the load is this contact angle, and the measuring means determines the revolution speed of the rolling elements in each row. The sensor comprises a pair of revolution speed detection sensors to be detected, and the computing unit is based on a detection signal representing the revolution speed of the rolling elements in each row sent from both the revolution speed detection sensors. The load measuring device for a wheel support rolling bearing unit according to any one of claims 1 to 3, wherein a load applied between the outer ring equivalent member and the inner ring equivalent member is calculated.   A rotation speed detection sensor that detects a rotation speed of a rotating wheel that rotates during use of the outer ring equivalent member and the inner ring equivalent member is provided, and the computing unit rotates the rotation speed of the rotating wheel that is fed from the rotation speed detection sensor. The wheel support according to claim 4, wherein a load applied between the outer ring equivalent member and the inner ring equivalent member is calculated on the basis of a detection signal indicating the rotation speed of the rolling elements in each row. Load measuring device for rolling bearing units.   The load acting on the inner ring equivalent member and the outer ring equivalent member constituting the wheel support rolling bearing unit, calculated by a load measuring device incorporated in the wheel support rolling bearing unit, and the inner ring equivalent member and the outer ring equivalent member. The running stability of the vehicle is determined based on at least the load of the moment generated with respect to the perpendicular line that intersects the central axis of the inner ring equivalent member and the outer ring equivalent member and the rotational speed of the rotating wheel that rotates during use. In a vehicular travel stabilization device that performs control for ensuring, the load measuring device is a load measuring device for a wheel bearing rolling bearing unit according to any one of claims 1 to 5. Vehicle travel stabilization device.   Control for ensuring the running stability of the vehicle is performed based on at least the load among the load, moment and rotational speed, the vehicle speed, and the steering angle and steering force of the steering wheel obtained from the power steering device. The vehicle travel stabilization device according to claim 6.   The vehicle travel stabilization device according to claim 7, wherein the vehicle speed is obtained from the rotational speed. During the control for ensuring the running stability of the vehicle, a braking force is applied to the wheel by at least one brake device among the brake devices attached to each wheel regardless of whether or not the brake pedal is operated. The vehicle running stability according to any one of claims 6 to 8, wherein at least one of brake control, control for adjusting an assist force of the power steering device, and control for adjusting a gear ratio is performed. Device.

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