JP2006308465A - Load measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a structure capable of acquiring an essentially needed load which acts across a road surface and an outer circumferential surface of a wheel, by adding/subtracting (compensating) an additive load associated with braking to/from a load acting across an outer ring 1 and a hub 2. <P>SOLUTION: A basic measurement load value which is an axial load acting across the outer ring 1 and the hub 2, is acquired based on a phase difference between output signals from a pair of Hall ICs 11a, 11b. Moreover, a braking error component which is a load acting across the outer ring 1 and the hub 2, is acquired based on an oil pressure introduced into a cylinder chamber of a disc brake. Next, the essentially needed load is obtained precisely by adding/subtracting the braking error component to/from the basic measurement load value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  A load measuring device according to the present invention is incorporated in a wheel bearing rolling bearing unit that supports a wheel of a vehicle (automobile), for example, so as to be rotatable with respect to a suspension device, and measures the magnitude of a load applied to the wheel. It is used to secure stable operation.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. In order to ensure the running stability of the vehicle, a running state stabilizing device for the vehicle such as an antilock brake system (ABS) or a traction control system (TCS) is widely used. According to these running state stabilizing devices such as ABS and TCS, the running state of the vehicle at the time of braking or acceleration can be stabilized, but in order to ensure this stability even under more severe conditions, the vehicle It is necessary to control the brakes and the engine by incorporating more information that affects the running stability of the vehicle.

  That is, in the case of the conventional running state stabilizing device such as ABS or TCS, since so-called feedback control is performed to detect the slip between the tire and the road surface and control the brake and the engine, the brake and engine Control is delayed for a moment. In other words, in order to improve performance under severe conditions, the so-called feed-forward control prevents slippage between the tire and the road surface, or the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different. Cannot be prevented.

  In order to cope with such a problem, in order to perform the feedforward control or the like, one of a radial load and an axial load applied to the wheel is applied to the rolling bearing unit for supporting the wheel with respect to the suspension device. Or it is possible to incorporate a load measuring device for measuring both. Conventionally, what was described in patent documents 1-5 is known as a wheel bearing rolling bearing unit with a load measuring device which can be used in such a case.

  Of these, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. In the case of the first example of the conventional structure, the outer ring and the hub are measured by measuring the radial displacement between the outer ring that does not rotate and the hub that rotates on the inner diameter side of the outer ring by a non-contact displacement sensor. The radial load applied between and is calculated. The obtained radial load is used not only to properly control the ABS but also to inform the driver of a bad loading condition.

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. In the case of the second example of the conventional structure described in Patent Document 2, bolts for connecting the fixed side flange to the knuckle are screwed at a plurality of positions on the inner side surface of the fixed side flange provided on the outer peripheral surface of the outer ring. Each load sensor is attached to a portion surrounding the screw hole. Each load sensor is clamped between the outer surface of the knuckle and the inner surface of the fixed flange in a state where the outer ring is supported and fixed to the knuckle. In the case of the load measuring device for the rolling bearing unit of the second example having such a conventional structure, the axial load applied between the wheel and the knuckle is measured by the load sensors.

  Further, in Patent Document 3, the displacement sensor unit supported at four positions in the circumferential direction of the outer ring and the L-shaped detection ring that is externally fitted and fixed to the hub are used to detect the above-described outer ring at the four positions. A structure is described in which the displacement of the hub in the radial direction and the axial direction is detected, and the direction of the load applied to the hub and the magnitude thereof are determined based on the detection values of the respective parts.

  Further, in Patent Document 4, a strain gauge for detecting dynamic strain is provided in a member corresponding to an outer ring whose rigidity is partially reduced, and the revolution speed of the rolling element is determined from the passing frequency of the rolling element detected by the strain gauge. A method for determining the axial load applied to the rolling bearing from the revolution speed is described.

  Further, in Patent Document 5, the revolution speed of the rolling elements provided with contact angles in opposite directions is changed depending on the direction and magnitude of the load, and the outer ring that is a stationary side race ring is rotated. The structure which calculates | requires one or both of the radial load and axial load which act between the hubs which are a side track ring is described.

  In addition, although not disclosed, for example, in Japanese Patent Application No. 2004-279155, the displacement between the two race rings is measured by an encoder supported on the rotation side race ring and a sensor supported on the stationary side race ring. From this displacement, a structure for obtaining a load applied between the two race rings is disclosed. In the load measuring apparatus according to the prior invention, an encoder in which the characteristics of the detected surface are alternately changed in the circumferential direction is supported concentrically with the rotation-side raceway on a part of the rotation-side raceway. The sensor is supported by a non-rotating portion such as the stationary-side track ring with the detection unit facing the detection surface, and changes its output signal in response to a change in the characteristics of the detection surface. Let A computing unit calculates a load acting between the two race rings based on the output signal of the sensor. For this purpose, the pitch or phase at which the characteristics of the surface to be detected change in the circumferential direction is continuously changed according to the acting direction of the load to be detected, and the computing unit outputs the output signal of the sensor. It has a function of calculating the load based on a pattern in which changes.

  4 to 11 show two examples of specific structures disclosed in Japanese Patent Application No. 2004-279155. As shown in FIGS. 4 and 8, each of the structures according to each of the prior inventions supports and fixes (couples) the wheel to the inner diameter side of the outer ring 1 which is a stationary side race ring that does not rotate while being supported by the suspension device. A hub 2 that is a rotating side race wheel that rotates together with the wheel in a fixed state is rotatably supported via a plurality of rolling elements 3 and 3. The encoders 4, 4 a are externally fitted and fixed to the intermediate part of the hub 2, and the sensors 5, 5 a are arranged between the rolling elements 3, 3 arranged in a double row at the axially intermediate part of the outer ring 1. Each pair is provided in a state where the respective detection units are close to and opposed to the outer peripheral surfaces of the encoders 4 and 4a, which are detected surfaces. In addition, it is appropriate to incorporate a magnetic detection element such as a Hall IC, a Hall element, an MR element, or a GMR element in the detection part of the sensors 5 and 5a.

  In the case of the structure of the first example of the prior invention shown in FIGS. 4 to 7, the encoder 4 is made of a permanent magnet. On the outer peripheral surface of the encoder 4 which is a detection surface, portions magnetized in the N pole and portions magnetized in the S pole are alternately arranged at equal intervals in the circumferential direction. The boundary between the part magnetized in the N pole and the part magnetized in the S pole is inclined by the same angle with respect to the axial direction of the encoder 4, and the inclination direction with respect to the axial direction of the encoder 4 is The axial directions are opposite to each other at the intermediate portion. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

  The positions where the detection parts of the sensors 5 and 5 face the outer peripheral surface of the encoder 4 are the same with respect to the circumferential direction of the encoder 4. In other words, the detection parts of the sensors 5 and 5 are arranged on the same virtual plane including the central axis of the outer ring 1. Further, in the state where the axial load is not applied between the outer ring 1 and the hub 2, the axial direction intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is related to the circumferential direction. The installation positions of the members 4, 5, and 5 are regulated so that the most protruding part (the part in which the tilt direction of the boundary changes) is exactly at the center position between the detection parts of the sensors 5 and 5. is doing. In this way, by making the portion where the inclination direction of the boundary changes in the center position, errors due to temperature difference between the inner and outer rings and deformation due to thermal expansion (even if no displacement occurs, the temperature difference between the inner and outer rings The so-called offset, which causes a phase difference, can be kept small. In the case of the first example of the present invention, since the encoder 4 is made of a permanent magnet, it is not necessary to incorporate a permanent magnet on both the sensors 5 and 5 side.

  In the case of the first example of the prior invention configured as described above, when an axial load is applied between the outer ring 1 and the hub 2, the phase at which the output signals of the sensors 5, 5 change is shifted. That is, in the neutral state where an axial load is not applied between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are not relatively displaced, the detecting portions of the sensors 5 and 5 are 7A is opposed to a portion that is shifted by the same amount in the axial direction from the most protruding portion. Accordingly, the phases of the output signals of the sensors 5 and 5 coincide as shown in FIG.

  On the other hand, when a downward axial load acts on the hub 2 to which the encoder 4 is fixed in FIG. 7A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), The detection parts of both sensors 5 and 5 are opposed to the broken lines B and B in FIG. 7A, that is, the parts different from each other in the axial direction from the most protruding part. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4 is fixed as shown in FIG. 7A, the detecting portions of both the sensors 5 and 5 are connected to the chain line H shown in FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG.

  As described above, in the case of the first example of the prior invention, the phases of the output signals of the sensors 5 and 5 are shifted in the direction corresponding to the direction of the axial load applied between the outer ring 1 and the hub 2. Further, the degree to which the phase of the output signals of the sensors 5, 5 is shifted by this axial load (displacement amount) increases as the axial load increases. Accordingly, in the case of the first example, the presence or absence of a phase shift between the output signals of the sensors 5 and 5 and, if there is a shift, based on the direction and magnitude of the outer ring 1 and the hub 2. The direction and magnitude of the axial load acting in between are obtained.

  Next, in the case of the structure of the second example of the present invention shown in FIGS. 8 to 11, an encoder 4 a made of a magnetic metal plate is externally fitted and fixed to an intermediate portion of the hub 2. Slit-like through holes 6a and 6b and column portions 7a and 7b are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 4a, which is the detection surface. The through holes 6a and 6b and the column portions 7a and 7b are inclined by the same angle with respect to the axial direction of the encoder 4a, and the inclined direction with respect to the axial direction is bounded by the intermediate portion in the axial direction of the encoder 4a. Are in opposite directions. That is, the encoder 4a is formed with through holes 6a and 6a inclined in the same direction in the predetermined direction with respect to the axial direction in one half of the axial direction, and in the opposite direction to the predetermined direction in the other half of the axial direction. The through holes 6b and 6b inclined by the same angle are formed.

  On the other hand, the pair of sensors 5a and 5a is installed between the rolling elements 3 and 3 arranged in a double row at the axially intermediate portion of the outer ring 1, and the detection portions of both the sensors 5a and 5a are provided. It is made to face and oppose the outer peripheral surface of the encoder 4a. The positions where the detection parts of both the sensors 5a and 5a face the outer peripheral surface of the encoder 4a are the same in the circumferential direction of the encoder 4a. A rim portion 8 that is located between the through holes 6a and 6b and continues to the entire circumference in a state where an axial load does not act between the outer ring 1 and the hub 2 includes the sensors 5a and 5a. The installation positions of the members 4a, 5a, and 5a are regulated so as to exist at the center position between the detection units. In the case of the second example of the present invention, since the encoder 4a is made of a simple magnetic material, it is necessary to incorporate permanent magnets on the two sensors 5a and 5a side.

  In the case of the second example of the prior invention configured as described above, when an axial load acts between the outer ring 1 and the hub 2 (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), the above-described prior invention. As in the case of the first example, the phase at which the output signals of the sensors 5a and 5a change is shifted. That is, in a state where an axial load is not applied between the outer ring 1 and the hub 2, the detecting portions of the sensors 5a and 5a are on the solid lines A and B in FIG. It faces a portion that is displaced from the portion 8 by the same amount in the axial direction. Therefore, the phases of the output signals of the sensors 5a and 5a coincide as shown in FIG.

  On the other hand, when a downward axial load is applied to the hub 2 to which the encoder 4a is fixed as shown in FIG. 11A, the detecting portions of the sensors 5a and 5a are shown in FIG. The broken lines B and B, that is, the portions that are different from each other in the axial direction from the rim portion 8 face each other. In this state, the phases of the output signals of the sensors 5a and 5a are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4a is fixed as shown in FIG. 11A, the detecting portions of both the sensors 5a and 5a are connected to the chain line H shown in FIG. , C, that is, the axial displacement from the rim 8 opposes different parts in the opposite direction. In this state, the phases of the output signals of the sensors 5a and 5a are shifted as shown in FIG.

As described above, in the case of the second example of the prior invention, as in the case of the first example of the previous invention, the phases of the output signals of the sensors 5a and 5a are between the outer ring 1 and the hub 2. It shifts in the direction according to the direction of the axial load applied to. Further, the degree of displacement (displacement amount) of the output signals of the sensors 5a and 5a due to the axial load increases as the axial load increases. Therefore, also in the case of the second example, there is an action between the outer ring 1 and the hub 2 based on the direction and size of the output signal of both the sensors 5a and 5a, if there is a phase shift and if there is a shift. The direction and magnitude of the axial load is determined.
If the encoder is configured in an annular shape, the side surface in the axial direction of the encoder is a detection surface, and the detection portions of the pair of sensors are opposed to the detection surface in a state shifted in the radial direction, the above It is also possible to determine the displacement in the radial direction between the outer ring 1 and the hub 2 and thus the radial load applied between the outer ring 1 and the hub 2.

  In the case of the conventional structure shown in Patent Documents 1 to 5 as well as the structure according to the prior invention as shown in FIGS. 4 to 11 described above, as described below, except during braking ( The obtained load is equivalent or highly related to the load acting between the outer peripheral surface of the wheel (tire) and the road surface (when driving at a constant speed and during acceleration). Therefore, it is possible to perform feedforward control for ensuring the running stability of the vehicle based on the obtained load. However, such control for ensuring driving stability by feedforward control is important not only during constant speed driving or acceleration driving (rather than during constant speed driving or acceleration driving) but also during braking. There are many. Therefore, it is important that the load acting between the outer peripheral surface of the wheel and the road surface can be accurately measured only during braking. For this purpose, the load applied between the outer ring, which is a stationary side race ring, and the hub, which is a rotary side race ring, is obtained along with braking. It is necessary to obtain the load acting between the outer peripheral surface of the wheel and the road surface by adjusting (compensating) the load acting during the road.

  For example, consider a case where the braking device is a disc brake having a disc rotor and a caliper. Of these, the disk rotor is fixed to the hub together with the wheel, and rotates together with the hub. The caliper is fixed to a knuckle that constitutes a suspension device together with the outer ring (in the case of an opposed piston type), or supported by the support fixed to the knuckle so as to be able to displace the outer ring in the axial direction. (For floating caliper type). In any case, during braking, hydraulic pressure is introduced into a cylinder provided in the caliper, and a pair of pads are pressed against both side surfaces of the disk rotor by pushing out a piston that is oil-tightly fitted in the cylinder ( Hold tightly). At this time, the force with which both the pads are pressed against both sides of the disk rotor is somewhat (especially in the case of the floating caliper type) due to the resistance of the hydraulic piping and the sliding resistance between the support and the caliper. )) Become non-uniform.

  For this reason, an axial load (a difference in pressing force on both sides) is applied to the hub via the disk rotor. This axial load is generally smaller than the load acting between the outer peripheral surface of the wheel and the road surface. However, since the load acting between the outer peripheral surface of the wheel and the road surface is irrelevant (does not affect the running stability), the feedforward control is performed as long as the load applied during braking is not compensated. It cannot be performed with high accuracy. Further, when the braking device is a drum brake, a radial load may be generated separately from a load acting between the outer peripheral surface of the wheel and the road surface during braking.

  Patent Document 6 describes a structure in which a sensor is provided on a caliper carrier. According to such a structure described in Patent Document 6, it is assumed that the axial load applied to the rolling bearing unit in accordance with the operation of the disc brake as the braking device is obtained from the detection signal of the sensor. . However, it is considered that the sensor provided on the caliper carrier does not necessarily accurately determine the force associated with the load error component. In addition, an increase in cost and weight is inevitable, for example, a sensor and a signal extraction harness must be installed in a limited space.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365 JP 2005-31063 A JP 2002-350254 A

  In view of the circumstances as described above, the present invention can be easily configured without adding an extra sensor, and a load applied along with braking can be accurately obtained, and this load can be used as a stationary member such as an outer ring. To achieve a structure that can obtain the load that is originally required, such as the load that acts between the outer peripheral surface of the wheel and the road surface, by adjusting (compensating) the load acting between the wheel and the rotating member such as the hub. Invented.

  The load measuring device according to the present invention includes a load measuring means for obtaining a load acting between the rotating member and the stationary member, a braking force detecting means for obtaining a magnitude of a braking force applied to the rotating member by the braking means, Is provided. And it has a function which correct | amends the value of the load which the said load measurement means calculates | requires based on the magnitude | size of this braking force which this braking force detection means calculated | required.

  According to the load measuring device of the present invention configured as described above, the load applied during braking is adjusted (compensated) with respect to the load acting between the stationary member such as the outer ring and the rotating member such as the hub. Thus, the load that is originally desired, such as a load acting between the outer peripheral surface of the wheel and the road surface, can be obtained.

When carrying out the present invention, preferably, as described in claims 2 to 3, the rotating member is a rotating side bearing ring of a wheel bearing rolling bearing unit for supporting a wheel of an automobile, and the stationary member is Let it be a stationary side bearing ring which constitutes this wheel support rolling bearing unit. The braking means is a brake that applies resistance to the rotation of the wheel.
According to a second aspect of the present invention, the braking force detecting means includes a hydraulic pressure sensor for detecting a hydraulic pressure that rises as the brake pedal is depressed to operate the brake.
Alternatively, as described in claim 3, the braking force detection means includes a hydraulic pressure control circuit that generates a signal for increasing the hydraulic pressure when the brake pedal for depressing the brake is depressed.
By adopting such a configuration, the magnitude of the braking force can be easily obtained.

Preferably, when carrying out the present invention, for example, as described in claim 4, an encoder that is supported concentrically with a part of the rotating member and rotates together with the rotating member, and a detection unit are provided. A sensor supported by a stationary member in a state of being opposed to the detection surface of the encoder, and an arithmetic unit for obtaining a relative displacement between the stationary member and the rotating member based on an output signal of the sensor. Among these, the encoder changes the characteristics of the detected surface concentric with the rotation center of the rotating member alternately and at equal intervals in the circumferential direction, and changes the phase of the detected surface characteristics to change in the circumferential direction. It is assumed that it is continuously changed according to the direction of the displacement to be detected. The computing unit obtains a relative displacement amount between the stationary member and the rotating member based on a change pattern of the output signal of the sensor, and further rotates with the stationary member based on the relative displacement amount. It has a function of obtaining a load acting between the members.
Alternatively, as described in claim 5, as in the structure described in the above-mentioned Patent Document 5, the rotation-side track provided on the peripheral surface of the rotation-side raceway and the peripheral surface of the stationary-side raceway are opposed to each other. A plurality of rolling elements are provided so as to be able to roll freely with a contact angle provided between the stationary side track provided. And a load measurement means calculates | requires the load added between the said rotation side track ring and the said stationary side track ring based on the change of the revolution speed of each of these rolling elements.
The present invention adds a braking force detection means to a structure having a load measuring device as described in Patent Documents 1 to 4 described above, and based on the magnitude of the braking force obtained by the braking force detection means. It is also possible to implement in a mode in which the load value obtained by the load measuring means is corrected. However, if the configuration described in the above fourth to fifth aspects is adopted, it can be carried out using only a sensor obtained at a relatively low cost, which is advantageous in terms of cost.

  1 to 3 show an embodiment of the present invention. The encoder 4b, which is externally fitted and fixed to the intermediate portion of the hub 2 which is the rotating side raceway, is formed in a cylindrical shape by a magnetic metal plate, and has a plurality of "<" shapes at the center in the width direction. The through-holes 6 are formed at equal intervals in the circumferential direction. Each of these through-holes 6 and 6 protrudes (or is depressed) most in the circumferential direction at the center in the width direction of the outer peripheral surface, which is the detected surface of the encoder 4b.

  On the other hand, a mounting hole 9 is formed in a portion facing the outer peripheral surface of the encoder 4b at a middle portion in the axial direction of the outer ring 1 which is a stationary-side raceway so as to penetrate the outer ring 1 in the radial direction. The sensor unit 10 is inserted into the mounting hole 9 from the outside in the radial direction. The sensor unit 10 includes a pair of Hall ICs 11a and 11b, which are signal generation units, and a single permanent magnet 12. Of these Hall ICs 11a and 11b, one end surface functioning as a detection unit is placed close to and opposed to the outer peripheral surface of the encoder 4b through a detection gap having a small thickness (for example, about 0.5 to 2 mm). ing. The permanent magnet 12 is disposed on the opposite side (outer radial direction of the outer ring 1 and the hub 2) of the encoder 4b across the hall ICs 11a and 11b. The other end surfaces (upper surfaces in FIG. 1) of both the Hall ICs 11a and 11b are brought into contact with one end surface (lower end surface in FIG. 1) of the magnetization direction (vertical direction in FIG. 1) of the permanent magnet 12.

  The sensor unit 10 embeds and holds each of the members 11a, 11b, 12 in a synthetic resin holder 13 in a state where the Hall ICs 11a, 11b and the permanent magnet 12 are combined in the positional relationship. It consists of That is, the sensor unit 10 is a mold for injection-molding the holder 13 together with the members 11a, 11b, and 12 together with a harness for power supply and signal extraction, and an IC for waveform shaping. It is made by injecting synthetic resin into this cavity while it is set in the cavity. During the manufacturing operation of the sensor unit 10, the positional relationship between the two Hall ICs 11 a and 11 b is not shifted by the attractive force or the repulsive force based on the magnetic force of the permanent magnet 12. Further, this positional relationship can be easily regulated simply by abutting the two Hall ICs 11a and 11b on the single permanent magnet 12 at appropriate positions.

  With regard to the method for obtaining the axial load applied between the outer ring 1 and the hub 2 by the structure of the present embodiment configured as described above, basically the prior invention shown in the above-described FIGS. This is the same as the case of the second example. That is, when the outer ring 1 and the hub 2 are displaced in the axial direction based on the axial load, the phases of the pair of output signals based on the Hall ICs 11a and 11b are shifted as shown in FIG. Therefore, the direction and magnitude of the displacement in the axial direction are obtained from the direction and magnitude of the deviation by an arithmetic unit (not shown), and further, the direction and magnitude of the axial load are obtained from the direction and magnitude of the displacement. It is done. However, the direction and the magnitude of the axial load obtained in this way are merely related to the axial load applied between the outer ring 1 and the hub 2. As described above, at the time of braking accompanying the operation of the disc brake, the original measured load value that is the axial load applied between the outer ring 1 and the hub 2 includes the braking error that is the axial load accompanying braking. Ingredients included. Therefore, if this is the case, there will be a difference between this braking error component and the load to be measured, which is the value of the axial load that acts between the wheels and the road surface and is important for ensuring driving stability. become.

  Therefore, in the case of the present embodiment, the braking error component is obtained, and the braking error component is compensated (adjusted) with respect to the original measured load value, so that the measurement target load is obtained with high accuracy. . That is, when the action direction of the braking error component is the same as the action direction of the load to be measured, the action direction of the braking error component is reduced by subtracting the braking error component from the original measured load value. When the direction of the measurement target load is opposite, the braking error component is added to the original measurement load value to obtain the measurement target load with high accuracy. This point will be described with reference to FIGS.

  For example, a case where light braking is performed by a disc brake while traveling straight on a flat road will be described with reference to FIG. In this case, since an axial load based on gravity or centrifugal force is not applied to the vehicle body, the load to be measured remains almost zero as shown by a solid line a in FIG. On the other hand, the original measured load value changes to a value clearly deviating from 0, as shown by the broken line b in FIG. 2, due to the influence of the braking error component. Even if the control for ensuring the running stability of the vehicle is performed using the original measured load value as shown by the broken line (b), it is difficult to perform sufficiently high-precision control. On the other hand, at the time of braking by the disc brake, the oil pressure in the cylinder of the caliper constituting the disc brake changes as shown by the curve C in FIG. As is apparent from a comparison between this curve c and the braking error component that is the difference between the solid line A and the broken line B, there is a clear relationship (almost proportional relationship) between the braking error component and the hydraulic pressure. ) Exists. Therefore, if the braking error component is obtained based on the hydraulic pressure in the cylinder represented by the curve C, and this braking error component is compensated (reduced) with respect to the original measured load value indicated by the broken line b). A corrected load value close to the load to be measured, which is indicated by a solid line A in FIG. In FIG. 2C, the corrected load value obtained in this way is indicated by a chain line d. The solid line A shown in FIG. 2C is the load to be measured.

  Further, FIG. 3 shows a measurement target load, an original measurement load value, a hydraulic pressure, and a corrected load value at the time of sudden braking. The meanings of the lines A to D are the same as those in FIG. As apparent from FIG. 3, the stability of the vehicle body is lost as a result of sudden braking. As a result, the measurement target load itself also changes from 0, but a braking error component is obtained based on the hydraulic pressure, and compensation for the original measurement load value is performed. Thus, the load to be measured can be obtained with high accuracy.

Sectional drawing which shows the Example of this invention. The diagram which shows the relationship between a to-be-measured load, the original measurement load value, a hydraulic pressure, and a correction load value at the time of light braking. The diagram which shows the relationship between a to-be-measured load, the original measurement load value, a hydraulic pressure, and a correction load value at the time of sudden braking. Sectional drawing which shows the 1st example of the rolling bearing unit with a displacement measuring device which concerns on a prior invention. The perspective view of the encoder built in this 1st example. Similarly development. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 2nd example of a prior invention. The perspective view of the encoder integrated in this 2nd example. Similarly development. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4, 4a, 4b Encoder 5, 5a Sensor 6, 6a, 6b Through-hole 7a, 7b Column part 8 Rim part 9 Mounting hole 10 Sensor unit 11a, 11b Hall IC
12 Permanent magnet 13 Holder

Claims (5)

  A load measuring means for obtaining a load acting between the rotating member and the stationary member; and a braking force detecting means for obtaining a magnitude of a braking force applied to the rotating member by the braking means. A load measuring device having a function of correcting the value of the load obtained by the load measuring means based on the magnitude of the braking force obtained by.   The rotating member is a rotating side bearing ring of a wheel bearing rolling bearing unit for supporting a wheel of an automobile, the stationary member is a stationary side bearing ring constituting the wheel supporting rolling bearing unit, and the braking means is the wheel. A brake that applies resistance to the rotation of the brake, and includes a hydraulic pressure sensor that detects the hydraulic pressure that rises as the brake force detection means depresses the brake pedal for operating the brake. The load measuring device according to claim 1.   The rotating member is a rotating side bearing ring of a wheel bearing rolling bearing unit for supporting a wheel of an automobile, the stationary member is a stationary side bearing ring constituting the wheel supporting rolling bearing unit, and the braking means is the wheel. A brake that applies resistance to the rotation of the brake and includes a hydraulic control circuit that generates a signal for increasing the hydraulic pressure when the braking force detecting means depresses the brake pedal for operating the brake. The load measuring device according to claim 1, wherein   An encoder that is supported by a part of the rotating member concentrically with the rotating member and rotates together with the rotating member, a sensor that is supported by the stationary member in a state in which the detection unit faces the detection surface of the encoder, and the sensor And an arithmetic unit for obtaining a relative displacement between the stationary member and the rotating member based on the output signal of the output member, and the encoder includes a circle that determines the characteristics of the detected surface concentric with the rotation center of the rotating member. The phase is changed alternately and at equal intervals with respect to the direction, and the phase at which the characteristic of the detected surface changes with respect to the circumferential direction is continuously changed according to the direction of the displacement to be detected. Based on the change pattern of the output signal of the sensor, a relative displacement amount between the stationary member and the rotating member is obtained, and further, an action is performed between the stationary member and the rotating member based on the relative displacement amount. That has the function of determining the load, the load measuring apparatus according to any one of claims 1 to 3.   A plurality of rolling elements roll with a contact angle between a rotating track provided on the circumferential surface of the rotating raceway and a stationary track provided on the circumferential surface of the stationary raceway, which are opposed to each other. The load measuring means has a function of obtaining a load applied between the rotation side raceway and the stationary side raceway based on a change in revolution speed of each rolling element. The load measuring apparatus described in any one of 1-3.

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