JP4325376B2 - Attitude stabilization device for vehicles - Google Patents

Description

  The present invention is directed to a vehicle attitude stabilization device for preventing a vehicle body from rolling during turning of an automobile or a vehicle body from pitching during acceleration / deceleration and maintaining the vehicle body and a road surface close to parallel. Regarding improvements.

When the vehicle is turning, the vehicle body is tilted (rolled) in the width direction in a direction in which the outside in the turning direction is low and the inside is also high due to the centrifugal force applied to the vehicle body. In addition, when braking, the components of the suspension device shrink at the front of the vehicle body as the load moves forward, and during acceleration, pitching occurs, where the components of the suspension device shrink at the rear of the vehicle body as the load moves backward.
Either rolling or pitching causes discomfort to the occupant and causes motion sickness, but in a significant case, it also impairs running stability.

For example, if the inclination of the vehicle body due to rolling becomes significant, the load of this vehicle body moves greatly outward in the turning direction, and an excessive load is applied to the wheels outside the turning direction, while the load applied to the wheels inside the turning direction becomes too small. . In this state, the grip force obtained for each wheel as a whole becomes smaller than when the load applied to each wheel is equal, and it becomes difficult to ensure running stability.
Further, if the front side of the vehicle body sinks more greatly than the rear side during braking, an excessive load is applied to the braking device attached to the front wheel, but the load applied to the braking device attached to the rear wheel becomes too small. In this state, the braking force obtained by the entire wheel is smaller than that when the braking force to be applied to each wheel is equal, and the braking distance is increased.
Further, when the rear side of the vehicle body sinks more greatly than the front side during sudden acceleration, the surface pressure of the contact portion (grounding portion) between the front wheel and the road surface becomes significantly lower than the surface pressure of the grounding portion related to the rear wheel. For this reason, in the case of a front-wheel drive vehicle, a significant slip occurs at the ground contact portion for the drive wheel (front wheel), and not only the acceleration intended by the driver cannot be obtained, but also the running stability is deteriorated, and further, the tire Noticeable wear.

  Suppressing rolling and pitching that cause various problems like this increases the damping force of the damper (shock absorber) built into the suspension system so that the vehicle body does not sink at the part where the vehicle body load is biased. It is possible by things. However, if the damping force of the damper is simply increased, the ride comfort is deteriorated, so that it is difficult to employ it except for special vehicles such as sports cars and competition vehicles. For this reason, an electronically controlled suspension as described in Non-Patent Document 1 or an active suspension as described in Non-Patent Documents 2 and 3 has been conventionally implemented in some automobiles.

In these electronically controlled suspensions and active suspensions, damping of dampers built into suspension systems that support each wheel based on signals from multiple sensors such as vehicle speed sensors, steering angle sensors, acceleration sensors and yaw rate sensors provided on the vehicle body Change the force or change the state of hydraulic pressure to the actuator. Specifically, based on the signal from the acceleration sensor, the damping force of the damper is increased (it is difficult to expand and contract), or the hydraulic pressure is introduced to the actuator to which the load is applied. In this case, the higher the vehicle speed and the larger the steering angle, the greater the damping force of the damper and the greater the degree of introduction of hydraulic pressure to the actuator.

  Conventionally, in order to control such electronically controlled suspension and active suspension, signals from an acceleration sensor and a yaw rate sensor installed mainly on the vehicle body side have been used. However, the vehicle body is a so-called sprung load that exists above the spring that constitutes the suspension device, and its behavior is affected by the resonance frequency of this spring. On the other hand, when the behavior of the vehicle body changes, a force based on the inertial mass of the vehicle body is generated in the opposite direction as a reaction force against the force input from the wheel, and the spring is contracted by the forces in both directions. In short, the mechanism when the posture of the vehicle body changes with respect to the road surface is as follows: [force is generated on the wheel side as the first stage] → [reaction force is generated based on the inertial mass of the vehicle body as the second stage] → [third stage As the spring of the suspension device is shrunk].

  In the case of a conventional electronically controlled suspension or active suspension, the behavior of the vehicle body when the reaction force is generated in the second stage is measured by the acceleration sensor or the yaw rate sensor, and the damping force of the damper is changed. It is configured to change the state of introduction of hydraulic pressure to. For this reason, it is inevitable that the timing for obtaining a signal for control is delayed although it is an extremely short time.

  On the other hand, what was described in patent documents 1 and 2 is known as a sensor which measures the state value which changes according to the running state of a car on the wheel side. FIG. 6 shows a rolling bearing unit with a load measuring device described in Patent Document 1 among them. In the first example of this conventional structure, a radial load applied to a wheel is measured, and a hub 2 which is a rotating wheel for coupling and fixing a wheel is supported on an inner diameter side of an outer ring 1 which is a stationary wheel supported by a suspension device. is doing. The hub 2 has a hub body 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, and a left end portion of each drawing excluding FIG. 3). 4 and the inner end portion of the hub body 4 (the end portion on the center side in the width direction in the assembled state in the vehicle, the right end portion of each drawing except FIG. 3) and are held down by the nut 5. And an inner ring 6. And the double row outer ring raceways 7 and 7 each formed on the inner peripheral surface of the outer ring 1 and each of which is a stationary side track, and the double row each formed on the outer peripheral surface of the hub 2 and each of which is a rotation side track. A plurality of rolling elements (balls) 9 a and 9 b are arranged between the inner ring raceways 8 and 8, respectively, so that the hub 2 can freely rotate 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.

  According to the 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. In Patent Document 1, a signal representing the radial load obtained in this way is used for ABS control and loading state defect detection. The use of a signal representing this load for suppressing rolling and pitching is not described in Patent Document 1.

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

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. As shown in FIG. 7, the rolling bearing unit with a load measuring device described in Patent Document 2 is provided with a rotation side flange 3a for supporting a wheel on the outer peripheral surface of the outer end 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. Patent Document 2 describes that a signal representing the axial load thus obtained is used to obtain a signal for rear wheel steering. The use of a signal representing this load in order to suppress rolling and pitching is not described in Patent Document 2.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Motoo Aoyama, “Red Badge Series / 245 / Super Illustration / A book that understands the latest mechanics of cars”, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001, p. 168-170 Mitsuhiko Kuroda, “Introduction to Automotive Engineering”, Grand Prix Publishing, Inc., April 25, 1990, p. 182-183 Hatanauchi Hata, “Evolution of automobiles”, Grand Prix Publishing Co., Ltd., November 5, 1987, p. 181-211

  In view of the circumstances as described above, the present invention realizes a vehicle posture stabilization device that can quickly detect the presence of force for changing the posture of a vehicle body and quickly perform control to stabilize the posture. Invented as much as possible.

The vehicle posture stabilization device of the present invention is present on the side where the distance between the vehicle body and the road surface is shortened in order to prevent the vehicle body from being inclined with respect to the road surface regardless of the load applied to the vehicle body in the horizontal direction. This suppresses the shrinkage of the components of the suspension device.
In particular, in the vehicle posture stabilization device of the present invention, the load measurement incorporated in the rolling bearing unit for rotatably supporting the wheel with respect to the vehicle body, because the distance between the vehicle body and the road surface is shortened. Judgment is based on the magnitude of the load measured by the device.

Of these, the rolling bearing unit is composed of a stationary wheel that does not rotate even when traveling, a rotating wheel that is arranged concentrically with the stationary wheel and that rotates when in use, and a portion of the stationary wheel and the rotating wheel that face each other. A plurality of rolling elements are provided between the stationary-side track and the rotation-side track, which are provided respectively, and are provided so as to be able to roll in a state in which opposite contact angles are provided between the two rows.
The load measuring device includes a pair of revolution speed detection sensors for detecting the revolution speeds of the rolling elements in both rows, a rotation speed detection sensor for detecting the rotation speed of the rotating wheel, And a calculator for calculating a load applied between the stationary wheel and the rotating wheel based on detection signals sent from both the revolution speed detecting sensor and the rotational speed detecting sensor.
The computing unit calculates a load applied between the stationary wheel and the rotating wheel based on the revolution speed of the rolling elements in both rows and the rotating speed of the rotating wheel.

According to the vehicle posture stabilization device of the present invention configured as described above, the presence of a force for changing the posture of the vehicle body can be detected quickly, and control for stabilizing the posture can be quickly performed. That is, as described above, when the vehicle body rolls or pitches, a force is generated on the wheel side as the first stage, and then a reaction force is generated based on the inertial mass of the vehicle body as the second stage. In the case of the conventional structure described in Non-Patent Documents 1 to 3 described above, the reaction force generated in the second stage is detected and controlled, whereas in the present invention, Control is performed by detecting the force generated in one stage. For this reason, as described above, control for stabilizing the posture of the vehicle body can be quickly performed.
Furthermore, the vehicle posture stabilization device of the present invention is constructed at a low cost because the load measuring device is composed of a pair of revolution speed detection sensors, a rotational speed detection sensor, and a calculator. Thus, it is possible to accurately measure the load applied between the stationary wheel and the rotating wheel.

When carrying out the present invention, for example, as described in claim 2, in order to prevent the distance between the vehicle body and the road surface from being shortened on one side in the width direction of the vehicle body as the vehicle body rolls. In addition, on the side where at least one of the axial load and the radial load measured by the load measuring device becomes large, it is possible to prevent the components of the suspension device from shrinking.
Alternatively, as described in claim 3, in order to prevent the distance between the vehicle body and the road surface from becoming shorter on one side in the front-rear direction of the vehicle body as the vehicle body pitches, On the side where the radial load to be measured is increased, the components of the suspension device are prevented from shrinking.
By configuring in this way, rolling or pitching, which is a typical state in which the vehicle body is inclined with respect to the road surface, can be effectively suppressed.

An example of a reference example related to the present invention will be described with reference to FIGS. The feature of the vehicle posture stabilization device of this reference example is to keep the vehicle body and the road surface close in parallel by preventing the vehicle body from rolling when the vehicle is turning or from being pitched during acceleration / deceleration. Therefore, a signal representing a load applied to each wheel (= a load applied between a stationary wheel and a rotating wheel of a rolling bearing which rotatably supports the wheel) is used. That is, when rolling or pitching occurs, the load applied to some of the four wheels provided in the automobile is greater than the load applied to the remaining wheels. Then, the vehicle body tends to sink (the distance between the vehicle body and the road surface is shortened) on the side of some wheels where the load is increased. Therefore, when the present reference example is carried out, the components of the suspension device are prevented from shrinking on the side where the load increases.

  Specifically, when the control target is an electronically controlled suspension as described in Non-Patent Document 1 described above, the damping force of the damper that constitutes the suspension device that supports the wheel that supports a large load is increased. , Making the total length of this damper difficult to shrink. As a result, the sinking of the vehicle body is suppressed on the wheel side that supports the large load. In order to increase the damping force of the damper, as described in Non-Patent Document 1, the opening area of the variable orifice incorporated in the damper is reduced. The opening area is narrowed as the load is increased. In addition, when the object of control is an active suspension as described in Non-Patent Documents 2 and 3 described above, the overall length of the actuator constituting the suspension device that supports the wheel that supports a large load is not reduced. Like. As a result, the sinking of the vehicle body is suppressed on the wheel side that supports the large load. In order to prevent the overall length of the actuator from shrinking, the pressure in the hydraulic chamber on the contraction side of the actuator can be reduced by switching a solenoid valve provided between the actuator and a pump for supplying pressure oil. Do it by raising it. In any case, the relationship between the magnitude of the load applied to each wheel and the degree to which the damping force of the damper of the suspension system that supports the wheel is changed or the degree to which the total length of the actuator is difficult to shrink is determined by experiment. They are installed in software as maps or empirical formulas and installed in a microcomputer constituting the controller.

  In any case, the position of the damper or actuator that should be prevented from shrinking, and the control after the degree to which shrinkage is to be restrained are described in Non-Patent Documents 1 to 3, etc., or actually installed in a commercial vehicle. This is almost the same as the case of an electronically controlled suspension or an active suspension that has been conventionally known. The structure of measuring the load applied to each wheel in order to determine the position of the damper or actuator that suppresses the contraction and the degree to suppress the contraction will be described. The load applied to each wheel can be measured by the structure described in Patent Document 1 shown in FIG. 6 or the structure described in Patent Document 2 shown in FIG. However, in the case of the structure shown in FIG. 6, since the displacement amount detected by the displacement sensor 11 in the radial direction between the outer ring 1 and the hub 2 is very small, in order to obtain this load accurately, the displacement sensor 11, it is necessary to use a highly accurate one. 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 structure shown in FIG. 7, it is necessary to provide the same number of load sensors 20 as the number of bolts 18 for supporting and fixing the outer ring 1 a 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.

On the other hand, in the case of this reference example , by devising the structure of the load measuring device of the rolling bearing unit, the load applied to each wheel can be accurately measured with a structure that can be manufactured at low cost. Then, the structure and operation of the load measuring device of the rolling bearing unit constituting the present reference example will be described with reference to FIGS. This reference example has a structure in which a load measuring device is incorporated into a rolling bearing unit for supporting driving wheels of an automobile (FR wheel, RR vehicle, rear wheel of MR vehicle, front wheel of FF vehicle, all wheels of 4WD vehicle). It shows. The hub 2b, which is a rotating wheel, is formed by fitting and fixing an inner ring 6 to the inner end of the hub body 4a. A rotation-side flange 3b for supporting the wheel is fixed to a portion near the outer end of the outer peripheral surface of the hub body 4a. Further, by forming inner ring raceways 8 and 8 which are rotation side raceways on the outer peripheral surface of the intermediate part of the hub body 4a and the outer peripheral surface of the inner ring 6, respectively, the double-row angular type is provided on the outer peripheral surface of the hub 2b. The inner ring raceway is provided.

  On the other hand, on the outer peripheral surface of the outer ring 1b, which is a stationary ring, arranged concentrically with the hub 2b around the hub 2b, a fixed side for supporting and fixing the outer ring 1b to the knuckle 16 constituting the suspension device. The flange 17 is fixed. Further, on the inner peripheral surface of the outer ring 1b, double-row angular type outer ring raceways 7 and 7, each of which is a stationary side raceway, are formed. A plurality of rolling elements (balls) 9a and 9b are provided between the outer ring raceways 7 and 7 and the inner ring raceways 8 and 8, respectively, so that the inner diameter of the outer ring 1b is increased. The hub 2b is rotatably supported on the side.

  When the rolling bearing unit as described above is used, the spline shaft 23 attached to the constant velocity joint 22 is inserted into the spline hole 21 formed in the center portion of the hub body 4a. The hub 2b is sandwiched from both sides in the axial direction between a nut 24 screwed to the tip of the spline shaft 23 and the housing 25 of the constant velocity joint 22. The fixed flange 17 is supported and fixed to the knuckle 16 by a plurality of bolts 26. Further, the braking disk 27 and the wheel 28 of the wheel are supported and fixed to the rotation side flange 3 b by a plurality of studs 29 and nuts 30.

  The rolling bearing unit or knuckle 16 as described above is provided with a revolution speed detecting sensor 31 and a rotational speed detecting sensor 15a. Among these, the revolution speed detection sensor 31 is for measuring the revolution speed of the rolling elements 9a, 9a in the outer row in the axial direction. A part of the outer ring 1b is used to measure the revolution speed of the double row outer ring raceways 7, 7. A mounting hole 10a formed so as to penetrate the outer ring 1b in the radial direction is attached to the intermediate portion. That is, the revolution speed detection sensor 31 is provided in a state where the mounting hole 10a is inserted from the radially outer side to the inner side, and the detection portion provided at the tip thereof is used as the rolling element 9a of the outer row. , 9a is opposed to the detected surface (one side surface in the axial direction) of the revolution speed detecting encoder 34, which is installed on the entire circumference of the rim portion of the cage 33.

  Further, the rotational speed detecting encoder 13a is fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 6, and the detected surface (one side surface in the axial direction) of the rotational speed detecting encoder 13a is supported by the knuckle 16. The detection unit provided at the tip of the rotation speed detection sensor 15a is opposed to the sensor. As the rotational speed detecting encoder 13a, those having various structures that have been used for detecting the rotational speed of the wheel in order to obtain signals for controlling ABS and TCS can be used. For example, the rotational speed detecting encoder 13a can be additionally provided on the inner surface of the slinger constituting the combination seal ring 37 for closing the inner end opening of the space 36 in which the rolling elements 9a and 9b are installed. . As the rotational speed detecting encoder 13a used in this case, a multipolar magnet having N poles and S poles alternately arranged on the inner surface can be preferably used. However, a simple encoder made of a magnetic material or one whose optical characteristics are changed alternately and at equal intervals in the circumferential direction can be used (in combination with an optical rotation detection sensor).

  In addition, as the revolution speed detection sensor 31 and the rotation speed detection sensor 15a, which are sensors that detect the rotation speed, magnetic rotation speed detection sensors can be preferably used. As this magnetic rotation speed detection sensor, an active sensor incorporating a magnetic detection element such as a Hall element, Hall IC, magnetoresistive element, MI element or the like can be preferably used. In order to construct an active type rotational speed detection sensor incorporating such a magnetic detection element, for example, one side surface of the magnetic detection element is directly or via a stator made of a magnetic material for detecting the revolution speed. It is made to oppose the to-be-detected surface of the encoder 34 (in the case of the revolution speed detection sensor 31) or the rotation speed detection encoder 13a (in the case of the rotation speed detection sensor 15a). When a permanent magnet encoder is used, a permanent magnet on the sensor side is not necessary.

  For example, when the revolution speed detection sensor 31 for detecting the revolution speed of the rolling elements 9a, 9a in the outer row is configured as described above, this revolution speed detection is performed along with the revolution of each of the rolling elements 9a, 9a. The characteristics of the magnetic detection elements that constitute the sensor 31 change. That is, with the revolution of the rolling elements 9a, 9a, the axially outer retainer 33 holding the rolling elements 9a, 9a rotates, and the revolution speed installed on the rim portion of the retainer 33 is rotated. S poles and N poles existing on the detection surface of the detection encoder 34 alternately pass in the vicinity of the detection surface of the revolution speed detection sensor 31. When a revolving speed detection encoder is made of a magnetic material (not a permanent magnet) and a permanent magnet is installed on the side of the revolving speed detection sensor, the revolving speed detection encoder is rotated. The amount of magnetic flux flowing through the magnetic detection element built in this revolution speed detection sensor changes. In any case, the frequency at which the characteristics of the magnetic detection element change is proportional to the revolution speed of the rolling elements 9a, 9a. Therefore, the revolution speed can be obtained based on the detection signal of the revolution speed detection sensor 31 incorporating this magnetic detection element.

In the case of this reference example, the axial load applied to the rolling bearing unit is detected by acting between the wheel 28 constituting the wheel and the knuckle 16 by the load measuring device for the rolling bearing unit configured as described above. That is, when the rolling bearing unit, which is a double row angular ball bearing, applies an axial load, the contact angle of the rolling elements 9a, 9a changes. For example, as shown by an arrow α in FIG. 1, when an inward axial load is applied, the contact angle of the rolling elements 9a, 9a in the outer (left side in FIG. 1) row increases. As is well known in the technical field of rolling bearings, the revolution speed of the rolling elements 9a, 9a constituting the angular ball bearing changes as the contact angle of these rolling elements 9a, 9a changes. Specifically, bears the axial load, with respect to the outer column, as the the axial load is increased, the rolling elements 9a, the revolution speed of 9a increases. Therefore, the axial load applied to the rolling bearing unit can be obtained by measuring the change in the revolution speed.

  For example, FIG. 3 shows the magnitude of the axial load when the axial load in the direction of the arrow α is applied to the back-row combined double row rolling bearing unit having the structure shown in FIGS. The relationship with the revolution speed of the rolling elements 9a and 9b is shown. The solid line a in FIG. 3 shows the relationship between the axial load and the revolution speed of the outer rolling elements 9a and 9a (the left side in FIG. 1), and the broken line b shows the axial load and the revolution speed of the inner rolling elements 9b and 9b. And the relationship with each other. The radial load was constant.

  As is clear from FIG. 3, regarding the rolling elements 9a and 9a in the row receiving the axial load, the magnitude of the axial load and the revolution speed of each of the rolling elements 9a and 9a are substantially proportional. Therefore, the axial load acting on the double row rolling bearing unit can be calculated by measuring the revolution speed of the rolling elements 9a, 9a. As the revolution speed detection sensor 31 for measuring the revolution speed, an inexpensive speed sensor that has been widely used for obtaining ABS or TCS control signals can be used. For this reason, the apparatus for measuring the axial load added to the said double row rolling bearing unit can be comprised at low cost. The relationship shown by the solid line a in FIG. 3 for obtaining the axial load is obtained in advance by experiment or calculation, and is input to an arithmetic unit for calculating the axial load.

In addition, the revolution speed of each of the rolling elements 9a and 9a changes based on a change in the axial load, and also changes depending on a preload and a radial load applied to the respective rolling elements 9a and 9a. Of these, the preload does not change depending on the running state, and therefore the influence can be removed by initial setting in advance. On the other hand, the radial load changes depending on the running state. However, this reference example is intended to suppress rolling that occurs during cornering, and both the axial load and the radial load applied to the wheels affect the occurrence of this rolling. Therefore, if the relationship between the load applied to each wheel by the combination of the axial load and the radial load and the degree to which the vehicle body rolls is known, the damping force control of the damper and the hydraulic pressure to the actuator are suppressed to suppress this rolling. It is possible to control the installation state of. In other words, in the case of this reference example , since it is for suppressing rolling of the vehicle body, it is not necessary to separately obtain the axial load and the radial load applied to the wheel. Therefore, it is only necessary to obtain the revolution speed of the outer rolling elements 9a, 9a that receive the axial load during the turning movement in the rolling bearing unit for supporting the wheel positioned on the radially outer side of the turning circle during the turning movement. In short, if the revolution speed of each of the rolling elements 9a, 9a and the degree to which the vehicle body rolls are known, the control for suppressing the rolling can be performed.

However, in the case of a double row rolling bearing unit for supporting the wheels of an automobile, the rotational speed of the hub 2b, which is a rotating wheel, changes during use, and the revolution speed of the rolling elements 9a, 9a is also the It changes in proportion to this rotational speed regardless of the load applied to. Therefore, the load applied to the wheel cannot be obtained unless the influence of the rotational speed is excluded. Therefore, in the case of this reference example , in addition to the revolution speed detection sensor 31, the rotation speed detection sensor 15a is provided so that the rotation speed of the hub 2b can be detected. The axial load (applied to the wheel) is determined by the rotational speed of the hub 2b detected by the rotational speed detection sensor 15a and the revolution speed of the rolling elements 9a, 9a detected by the revolution speed detection sensor 31. (Load) is calculated.

  Based on the signal representing the revolution speed sent from the revolution speed detection sensor 31 and the signal representing the rotation speed of the hub 2b sent from the rotation speed detection sensor 15a, the controller (not shown) The built-in calculator first calculates a speed ratio (= revolution speed of each rolling element 9a, 9a / rotation speed of the hub 2b) which is a ratio between the revolution speed and the rotation speed. Based on the change in the speed ratio, the degree of change in the revolution speed of the rolling elements 9a and 9a is obtained. Thus, if the degree of change in revolution speed based on the speed ratio is obtained, and the axial load (load applied to the wheel) applied to the double row rolling bearing unit is calculated based on the degree of change, the hub 2b Even when the rotational speed changes, the axial load (the load applied to the wheel) can be accurately calculated. It should be noted that the relationship between the speed ratio and the axial load (load applied to the wheel) is also obtained in advance by experiment or calculation and input to an arithmetic unit for (axial) load calculation.

When the vehicle posture stabilization device of this reference example is implemented to suppress rolling of the vehicle body, the load measuring device having the above-described configuration is used as a suspension device with four wheels provided on the front, rear, left and right of the vehicle body. Incorporated into a rolling bearing unit to support it freely. And the signal showing the load added to each wheel is sent to the controller for controlling the damping force control of the damper and the introduction state of the hydraulic pressure to the actuator. As described above, this controller performs the damping force control or the hydraulic pressure introduction state control based on a map or an empirical formula obtained in advance through experiments.

4 to 5 show an example of the embodiment of the present invention . In the case of this example, the axial load and the radial load applied to the wheel can be measured independently of each other. Therefore, in the case of this example , not only rolling of the vehicle body can be suppressed, but also pitching that occurs during acceleration / deceleration can be suppressed. Hereinafter, the structure and function of the load measuring device for a rolling bearing unit constituting this example will be described.

  A sensor unit 38 is inserted into a mounting hole 10b formed 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 which is a stationary ring, and a detection unit 39 provided at the tip of the sensor unit 38 is provided. Projecting from the inner peripheral surface of the outer ring 1. The detection unit 39 is provided with a pair of revolution speed detection sensors 31a and 31b and one rotational speed detection sensor 15b.

And the detection part of each revolution speed detection sensor 31a, 31b of these is provided in each retainer 33a, 33b 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 facing the encoders 34a and 34b. Further, the detecting portion of the rotation speed detecting sensor 15b is brought close to and opposed to the rotating speed detecting encoder 13b fitted and fixed to the intermediate portion of the hub 2 as a rotating wheel so that the rotating speed of the hub 2 can be detected. Yes. According to the load measuring device of the rolling bearing unit used in this example having such a configuration, the load (radial) applied between the outer ring 1 and the hub 2 regardless of the fluctuation of the rotational speed of the hub 2. Load and axial load).

That is, in the case of the load measuring device for the rolling bearing unit used in the present example as described above, an arithmetic unit (not shown) is used to detect the outer ring 1 and the above-described one based on the detection signals sent from the respective sensors 31a, 31b, 15b. One or both of a radial load and an axial load applied to the hub 2 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 31a and 31b, 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 15b. Further, the axial load is obtained by calculating a difference between the revolution speeds of the rolling elements 9a and 9b in the respective rows detected by the revolution speed detection sensors 31a and 31b, and the difference is detected by the rotation speed detection sensor 15b. 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. Preload F is applied to the rolling elements 9a and 9b arranged in a double row between the double row inner ring raceways 8 and 8 each being a rotation side raceway and the double row outer ring raceways 7 and 7 each being a stationary side raceway. ₀ and F ₀ are assigned. 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.
n _c = {1− (d · cos α / D) · (n _i / 2)} + {1+ (d · cos α / D) · (n _o / 2)}

As is evident from this equation, the rolling elements 9a, 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, the above-described Similarly, the contact angles α _a and α _b vary 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 obtains a load accurately by the revolution speed n _c is Can not. 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 case of the load measuring device for the rolling bearing unit used in this example , as described above, when the radial load Fz is obtained, the respective revolution speed detection sensors 31a and 31b detect. By determining the sum of the revolution speeds of the rolling elements 9a and 9b in each row, 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 15b 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. In the case of this example , unlike the above-described reference example, it is preferable that a sufficient preload remains when the axial load Fy is applied to the rolling elements in a row not supporting the axial load Fy. .

Also in this example , the load measuring device of the rolling bearing unit having the above-described configuration is incorporated in a rolling bearing unit for rotatably supporting four wheels provided on the front, rear, left and right sides of the vehicle body on the suspension device. And the signal showing the load added to each wheel is sent to the controller for controlling the damping force control of the damper and the hydraulic pressure introduction state to the actuator described above. As described above, the controller controls the damping force control or the hydraulic pressure introduction state based on a signal representing the load based on a map or an empirical formula obtained in advance through experiments.

In the case of this example , the control for suppressing rolling is performed in substantially the same manner as in the reference example described above. In other words, when suppressing rolling, the damping force control of the damper and the introduction of hydraulic pressure to the actuator are performed based on a map or experimental formula obtained in advance by taking into account the axial load Fy and the radial load Fz applied to the wheel. Control the state.
Furthermore, in the case of this example, since the radial load Fz applied to each wheel is obtained independently of the axial load Fy, the pitching of the vehicle body can be suppressed. In this case, the damping force of the damper that constitutes the suspension device that supports the wheel that supports the large radial load Fz is increased so that the entire length of the damper does not easily shrink, or the suspension device that supports the wheel that supports the large load is configured. To prevent the overall length of the actuator to shrink.

Sectional drawing of the rolling bearing unit incorporating the load measuring device which shows one example of the reference example regarding this invention . The A section enlarged view of FIG. The diagram which shows the relationship between an axial load and the revolution speed of the rolling element of each row | line | column. The sectional view of the rolling bearing unit which built in the load measuring device which shows one example of an embodiment of the invention. The schematic diagram for demonstrating the reason which can measure a load by the fluctuation | variation of revolution speed. Sectional drawing which shows the 1st example of the rolling bearing unit which incorporated the load measuring apparatus known conventionally. Sectional drawing which shows the 2nd example.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Outer ring 2, 2a, 2b Hub 3, 3a, 3b Rotation side flange 4, 4a Hub body 5 Nut 6 Inner ring 7 Outer ring race 8 Inner ring raceway 9a, 9b Rolling element 10, 10a, 10b Mounting hole 11 Displacement sensor 12 Sensor rings 13, 13a, 13b Rotation speed detection encoder 14 Covers 15, 15a, 15b Rotation speed detection sensor 16 Knuckle 17 Fixed flange 18 Bolt 19 Screw hole 20 Load sensor 21 Spline hole 22 Constant velocity joint 23 Spline shaft 24 Nut 25 Housing 26 Bolt 27 Disc 28 Wheel 29 Stud 30 Nut 31, 31a, 31b Revolution speed detection sensor 33, 33a, 33b Retainer 34, 34a, 34b Revolution speed detection encoder 36 Space 37 Combination seal ring 38 Sensor unit 9 detection unit

Claims (3)

Regardless of the load applied to the vehicle body in the horizontal direction, in order to prevent the vehicle body from inclining with respect to the road surface, the components of the suspension system existing on the side where the distance between the vehicle body and the road surface is shortened are prevented from shrinking. In a vehicle attitude stabilization device, the fact that the distance between the vehicle body and the road surface is shortened indicates that the load measuring device incorporated in the rolling bearing unit for rotatably supporting the wheel with respect to the vehicle body measures the load. Of these, the rolling bearing unit includes a stationary wheel that does not rotate during traveling, a rotating wheel that is arranged concentrically with the stationary wheel and that rotates when in use, and the stationary wheel and the rotating wheel. A plurality of rows are provided between the stationary-side track and the rotary-side track, which are provided in double rows on the opposite sides of each other, and are provided so as to be able to roll freely with opposite contact angles between the rows. Rolling element The load measuring device includes a pair of revolution speed detection sensors for detecting the revolution speeds of the rolling elements in both rows, and a rotation for detecting the rotation speed of the rotating wheel. A speed detection sensor, and a calculator that calculates a load applied between the stationary wheel and the rotating wheel based on detection signals sent from both the revolution speed detection sensor and the rotation speed detection sensor, This computing unit calculates a load applied between the stationary wheel and the rotating wheel based on the revolution speed of the rolling elements in both rows and the rotating speed of the rotating wheel. Attitude stabilization device for vehicles.   In order to prevent the distance between the vehicle body and the road surface from being shortened on one side in the width direction of the vehicle body as the vehicle body rolls, at least one of the axial load and the radial load measured by the load measuring device. The vehicle attitude stabilization device according to claim 1, wherein the suspension component is prevented from contracting on the side of increasing one load.   In order to prevent the distance between the vehicle body and the road surface from becoming shorter on one side in the longitudinal direction of the vehicle body as the vehicle body is pitched, the suspension device on the side where the radial load measured by the load measuring device increases. The posture stabilization device for a vehicle according to claim 1, wherein the component parts of the vehicle are prevented from shrinking.

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