JP2006258801A - Rolling bearing unit with displacement measuring device and rolling bearing unit with load cell device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit a variation of a changing timing of an output signal of a pair of the sensors 9a, 9b, irrespective of a direction and an amount of a relative displacement of both orbital rings of static and rotation sides, to simplify a process in an operation part calculating the above direction and amount of the relative displacement, to suppress a cost up of an operation part, and to provide a structure which can shorten a period required to specify the direction and the amount of the displacement. <P>SOLUTION: An initial phase difference is established between the output signals of the sensors 9a, 9b by changing the direction of the magnetic detection elements 10, 10 or the permanent magnets 11, 11 constituting of a pair of the sensors 9a, 9b. Further, the direction and the amount of the above displacement is determined by grasping the variation of the direction and the amount of a real phase difference as the phase difference between the output signals of the sensors 9a, 9b at this time point for the initial phase difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  A rolling bearing unit with a displacement measuring device and a rolling bearing unit with a load measuring device according to the present invention support, for example, a wheel of a vehicle (automobile) so as to be rotatable with respect to a suspension device, and can control the magnitude of a load applied to the wheel. Measure and use to ensure stable operation of the vehicle. Alternatively, it is incorporated in a rolling bearing unit for supporting the spindles of various machine tools, is used for measuring the load applied to the spindle and adjusting the feed rate of the tool appropriately.

  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. Furthermore, it is impossible to prevent the running stability of a truck or the like from being deteriorated based on the poor loading state.

  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 1-4 is known as a rolling bearing unit for wheel support 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.

  Furthermore, 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.

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

  In the second example of the conventional structure described in Patent Document 2, it is necessary to provide as many load sensors as the bolts for supporting and fixing the outer ring to the knuckle. For this reason, coupled with the fact that the load sensor itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. In addition, the structure described in Patent Document 3 is more expensive than the structure described in Patent Document 1 because sensors are installed at four positions in the circumferential direction of the outer ring. Furthermore, the method described in Patent Document 4 needs to reduce the rigidity of a part of the outer ring equivalent member, and it may be difficult to ensure the durability of the outer ring equivalent member.

  In view of such circumstances, Japanese Patent Application No. 2005-147642 discloses an invention for measuring the magnitude of a load applied to a rolling bearing unit based on the phase difference between the output signals of a pair of sensors arranged in the direction in which the load is applied. Is described. 5 to 12 show the structures of two examples of the prior invention disclosed in the above application. As shown in FIGS. 5 and 9, each of the structures according to the prior inventions supports and fixes (couples) a 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 a suspension device. A hub 2 which is a rotating side race ring to be fixed 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, MR, or GMR in the detection portion of the sensors 5 and 5a.

  In the case of the structure of the first example of the present invention shown in FIGS. 5 to 8, 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 8, facing the solid lines a and b in FIG. 8A, that is, the portions that are shifted from the most protruding portions by the same amount in the axial direction. 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. 8A (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. 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. 8A, 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. Therefore, in the case of the first example, based on the presence and absence of the phase shift of the output signals of the sensors 5 and 5 and the direction and magnitude of the shift, between the outer ring 1 and the hub 2. The direction and magnitude of the acting axial load can be determined.

  Next, in the case of the structure of the second example of the present invention shown in FIGS. 9 to 12, 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. 12A, the detecting portions of the sensors 5a and 5a are shown in FIG. The broken lines B and B, that is, portions opposite to each other in the axial direction from the rim portion 8 are opposed to 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. 12A, 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 above-described rolling bearing unit with a displacement measuring device as shown in FIGS. 5 to 12, as described above, the neutral state in which the outer ring 1 and the hub 2 are not relatively displaced. Then, the phases of the output signals of both sensors 5, 5 (5a, 5a) are made to coincide as shown in FIG. For this reason, there is a possibility that the direction and amount (size) of the relative displacement cannot be obtained accurately unless the direction of action of the load associated with the relative displacement is specified separately based on the signal from the G sensor or the like provided on the vehicle body. is there.

  That is, for example, when considering using the output signal of one sensor as a reference signal and using the output signal of the other sensor as a measurement signal for determining the direction of displacement, it changes depending on the direction of action of the load. Depending on the direction of the relative displacement, the context of the measurement signal with respect to the reference signal is reversed. For this reason, for example, when the phase difference between the reference signal and the measurement signal is −10 degrees, it may be determined that the phase difference is +350 degrees. Such a problem can be solved by incorporating information from a sensor that can specify the direction of the load, such as the G sensor. However, since the processing in the computing unit is complicated, the cost of the computing unit is increased, and the time required to specify the direction and magnitude of the load is increased. For example, for ensuring running stability This is disadvantageous in terms of speedy control.

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

  In the present invention, in view of the circumstances as described above, the processing in the computing unit is simple and the cost of the computing unit is suppressed. In addition, the direction and size of the displacement, and the load can be reduced. It was invented to realize a structure that can shorten the time required to specify the direction and size.

The rolling bearing unit with a displacement measuring device and the rolling bearing unit with a load measuring device according to the present invention include a rolling bearing unit and a displacement measuring device or a load measuring device.
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. And a plurality of rolling elements provided between the stationary side track and the rotating side track.
The displacement measuring device or the load measuring device includes an encoder, a pair of sensors, and an arithmetic unit.
Of these, the encoder is supported by a part of the rotation-side raceway, and alternately changes the characteristics of the detection surface concentric with the rotation-side raceway in the circumferential direction. The phase at which the characteristic changes with respect to the circumferential direction is a portion where the detection unit of at least one sensor faces, continuously according to the direction of displacement to be detected, and a portion where the detection unit of the other sensor faces. It is changed in a different state.
The two sensors are supported by portions that do not rotate with their respective detection portions facing the detection surface of the encoder, and change their output signals in response to changes in the characteristics of the detection surface.
Then, in a neutral state where the stationary side raceway and the rotation side raceway are not relatively displaced, as shown in FIG. 1, an initial phase difference δ is set between the detection signals of the two sensors. Yes.
Further, the computing unit is based on the period of the detection signals of the two sensors and the amount of deviation from the initial phase difference δ of the actual phase difference existing between the detection signals of the two sensors at each moment. The direction and amount of relative displacement between the stationary bearing ring and the rotating bearing ring, or the direction and magnitude of the load acting between the two bearing rings are calculated.

Note that the initial phase difference δ is not lost regardless of the relative displacement between the stationary side raceway and the rotation side raceway (always δ> 0, and the timing at which the output signals of both sensors change does not reverse). ) Set to a size of about. Accordingly, the magnitude of the initial phase difference δ is determined by the relative displacement that may occur between the stationary side raceway and the rotation side raceway (the load that can act between the two raceways). Size), the angle at which the boundary of the characteristic change of the surface to be detected is inclined with respect to the direction of the displacement, and the degree of swinging between the two race rings. In the case of the wheel bearing rolling bearing unit as shown in FIGS. 5 to 12 described above, the initial phase difference δ is set to 45 to 315 degrees (in a range of 1/8 to 7/8 of one cycle). It is preferable to do. That is, if the absolute value of the magnitude of the initial phase difference δ is ensured to be 1/8 or more of one cycle, the required measurement accuracy, quick measurement (number of characteristic changes during one rotation), etc. are ensured. However, the timing at which the output signals of the two sensors change can be prevented from being reversed.
It should be noted that the characteristic change pitch (number of characteristic changes per circle), shape, inclination angle, and the like of the detection surface of the encoder are appropriately set according to the magnitude of the initial phase difference δ.

According to the rolling bearing unit with a displacement measuring device and the rolling bearing unit with a load measuring device of the present invention configured as described above, the timing at which the output signals of both sensors change does not reverse based on the presence of the initial phase difference δ. For this reason, if the magnitude of the actual phase difference between the output signals of these sensors is known, the direction and amount of relative displacement between the stationary side raceway and the rotation side raceway, and therefore between these raceways, The direction and magnitude of the acting load can be determined. That is, if the actual phase difference is larger than the initial phase difference δ, the stationary side raceway and the rotation side raceway are relatively displaced in a predetermined direction by an amount corresponding to the difference between the two phase differences. I understand. Further, if the actual phase difference is smaller than the initial phase difference δ, the stationary side raceway and the rotation side raceway are opposite to the predetermined direction, and an amount corresponding to the difference between these two phase differences. It can be seen that the relative displacement only. In order to specify the direction and amount of this relative displacement, it is not necessary to incorporate information from other sensors for specifying the direction of the load of the G sensor or the like. For this reason, the processing in the computing unit is simple, the cost of the computing unit is suppressed, and the direction and size (amount) of the displacement and the direction and size of the load are specified. For example, the time required for the operation can be shortened and, for example, the control for ensuring the running stability can be performed quickly.
Incidentally, in order to obtain the load acting between the rotation side raceway and the stationary side raceway, it is not always necessary to obtain the relative displacement amount between the rotation side raceway and the stationary side raceway. That is, as described in claim 10, a load acting between the stationary side raceway and the rotation side raceway is directly applied to the computing unit based on the detection signals of the pair of sensors (the relative displacement). It is also possible to have a function of calculating (without going through the process of obtaining the direction and amount of

  In carrying out the present invention, for example, as described in claims 2 and 11, as shown in FIG. 2, as both sensors 9 a and 9 b, a magnetic sensing element 10 such as a Hall IC, a Hall element, MR, GMR, etc. A thing provided with the permanent magnet 11 is used. Among these, the magnetic sensing elements 10 of both the sensors 9a and 9b are in a state where the front faces the detected surface (outer peripheral surface) of the encoder 4a made of a magnetic material as shown in FIGS. It is arranged with. On the other hand, the permanent magnet 11 has one end surface in the magnetization direction in contact with or in close proximity to the back surface of the magnetic sensing element 10, which is the opposite side to the detected surface.

  The detection signals of the sensors 9a and 9b are made different between the sensors 9a and 9b by making the poles of the permanent magnet 11 in contact with or in close proximity to the back of the magnetic sensing element 10 different from each other. An initial phase difference is set between them. Specifically, in the case of one sensor 9a (right side in FIG. 2), the N pole of the permanent magnet 11 is placed on the back surface of the magnetic sensing element 10, and the other sensor 9b (left side in FIG. 2). In this case, the S poles of the permanent magnets 11 are brought into contact with or in close proximity to the back surface of the magnetic sensing element 10 so that the phases of the output signals of the sensors 9a and 9b are 180 degrees different in electrical angle. (Inverted).

Note that the arrow A in FIG. 2 represents the rotation direction of the encoder 4a. In FIG. 2, in order to clearly describe the configuration of each of the sensors 9a and 9b, the two sensors 9a and 9b are shown shifted with respect to the rotation direction of the encoder 4a. The phases of the sensors 9a and 9b with respect to the rotation direction of the encoder 4a coincide with each other.
If the configuration as described above is employed, the necessary initial phase difference δ can be easily set between the output signals of the sensors 9a and 9b. In the case of the structure shown in FIG. 2, it is necessary to use a magnetic material as the encoder 4a (the permanent magnet encoder 4 as shown in FIGS. 5 to 8 is used). Can't)

  When the present invention is implemented, for example, as shown in claims 3 and 12, as shown in FIGS. 3 and 4, both sensors 9 and 9 have the same structure as that described in claims 2 and 11 above. In addition, a device including a magnetic sensing element 10 such as a Hall IC, Hall element, MR, GMR or the like and a permanent magnet 11 is used. The front surfaces of the magnetic detection elements 10 of the sensors 9 and 9 are opposed to the detection surface (outer peripheral surface) of the magnetic material encoder 4a shown in FIGS. One end surface in the magnetization direction is brought into contact with or in close proximity to the back surface of the magnetic sensing element 10. In the case of the structure shown in FIGS. 3 to 4, the poles of the permanent magnet 11 that are in contact with or close to the back surface of the magnetic sensing element 10 are the same between the sensors 9 and 9. . Instead, the initial phase difference is set between the detection signals of the sensors 9 and 9 by making the arrangement directions of the magnetic sensing elements 10 different from each other. Specifically, by disposing the direction of arrangement of the magnetic sensing element 10 between these sensors 9, 9 by 180 degrees (arranged mirror-symmetrically with respect to a virtual plane orthogonal to the central axis of the encoder 4a). The phases of the output signals of the sensors 9 and 9 are different (inverted) by 180 degrees in electrical angle.

3 and 4 also, the arrow a represents the rotation direction of the encoder 4a. Also, in FIG. 3, in order to clearly describe the configuration of each of the sensors 9 and 9, these sensors 9 and 9 are illustrated with being shifted with respect to the rotation direction of the encoder 4a. In addition, the phases of the sensors 9 and 9 with respect to the rotation direction of the encoder 4a are matched with each other as shown in FIG.
Even if the configuration as described above is employed, the necessary initial phase difference δ can be easily set between the output signals of the sensors 9 and 9. In the case of the structure shown in FIGS. 3 to 4, each of the sensors 9 and 9 incorporates permanent magnets 11 and 11 that are independent from each other. One permanent magnet can be installed so as to span between the magnetic sensing elements 10 and 10. By adopting such a configuration, the cost can be reduced by facilitating the assembling work of the sensor unit in which a pair of sensors are incorporated in a single holder. In the case of the structure shown in FIGS. 3 to 4, an encoder made of a permanent magnet as shown in FIGS. 5 to 8 may be used as the encoder. However, in this case, the sensor-side permanent magnet is omitted.

Although not shown in the drawings, as described in claims 4 and 13, the output signal of one of the two sensors is subjected to arithmetic processing for giving a delay proportional to the rotational speed of the rotating raceway. The initial phase difference can be set between the detection signals of the two sensors.
Alternatively, although not shown in the drawings, as described in claims 5 and 14, the initial phase difference is set between the detection signals of both sensors by disposing both sensors in the rotational direction of the encoder. You can also do it. If both the sensors are embedded and held in a single synthetic resin holder, the set initial phase difference does not shift.

Further, when the present invention is implemented, preferably, as described in claims 6 and 15, the phase at which the characteristic of the detection surface of the encoder changes is changed so that the detection portion of one sensor faces the other sensor. With respect to the direction parallel to the central axis of the encoder, the detection unit is changed in the opposite directions by the same angle. Such a structure is the same structure as the prior invention shown in FIGS.
In the case of such a structure, it is possible to increase the phase difference between the output signals of the two sensors based on the relative displacement between the stationary side raceway and the rotation side raceway. For this reason, it is possible to improve the measurement accuracy of the amount of relative displacement between the two race rings, and hence the load acting between the two race rings.

Alternatively, as described in claims 7 and 16, the phase at which the characteristic of the detected surface of the encoder changes changes only in the part where the detection part of one sensor faces in the direction parallel to the central axis of the encoder. Let On the other hand, no change is made in this direction (a direction parallel to the central axis of the encoder) in a portion where the detection unit of the other sensor faces.
In the case of the invention described in claims 7 and 16, the phase difference between the output signals of the pair of sensors based on the relative displacement between the stationary-side raceway and the rotation-side raceway is the above-described claim 6, Although it is ½ of the case of the invention described in No. 15, the structure widely used for ABS and TCS has been diverted to the part of the other sensor and encoder combined with the other sensor. Can be made cheaper.

Further, when the inventions described in claims 1 to 7 are carried out, preferably, as described in claim 8, the calculator has a stationary side raceway and a rotation side raceway based on the calculated relative displacement amount. A function for calculating a load acting during the period is provided.
Further, when the invention described in claim 8 or the invention described in claims 10 to 16 is carried out, preferably, the rolling bearing unit is used for supporting a wheel of an automobile as described in claims 9 and 17. Hub unit. Then, in use, the stationary side race is supported by the suspension device of the automobile, and the wheel is coupled and fixed to the hub that is the rotation side race.
According to such a structure, it is possible to control the brakes and the engine by incorporating information necessary for ensuring the stability of the vehicle even under severe conditions.

The diagram which shows the output signal of a pair of sensor for demonstrating this invention. The principal part perspective view which shows the 1st example of the concrete structure in the case of implementing this invention. The principal part perspective view which shows the 2nd example. The figure seen from the radial direction of the encoder. 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 Encoder 5, 5a Sensor 6a, 6b Through-hole 7a, 7b Column part 8 Rim part 9, 9a, 9b Sensor 10 Magnetic detection element 11 Permanent magnet

Claims (17)

A rolling bearing unit and a displacement measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The displacement measuring device includes an encoder, a pair of sensors, and an arithmetic unit, and the encoder is supported by a part of the rotating side raceway, and the rotating side track The characteristics of the surface to be detected that are concentric with the wheel are alternately changed in the circumferential direction, and the phase at which the characteristics of the surface to be detected changes in the circumferential direction is detected at the part where the detection part of at least one sensor faces. According to the direction of the displacement to be changed, and the detection part of the other sensor is changed in a state different from the facing part,
The two sensors are supported by a portion that does not rotate in a state in which the respective detection units face the detection surface of the encoder, and change the output signal in response to a change in the characteristics of the detection surface.
In the neutral state where the stationary side raceway and the rotation side raceway are not relatively displaced, an initial phase difference is set between the detection signals of the two sensors,
The computing unit is based on the period of the detection signals of the two sensors and the amount of deviation from the initial phase difference of the actual phase difference existing between the detection signals of the two sensors at each moment. A rolling bearing unit with a displacement measuring device for calculating the direction and amount of relative displacement between the bearing ring and the rotation-side bearing ring.   In both sensors, one end surface in the magnetization direction is applied to the magnetic sensing element arranged with the front surface facing the detection surface of the encoder and the back surface of the magnetic detection element opposite to the detection surface. It is provided with a permanent magnet that is in contact with or in close proximity to each other, and by making the poles of the permanent magnet that are in contact with or in close proximity to the back of the magnetic sensing element between the two sensors different from each other, The rolling bearing unit with a displacement measuring device according to claim 1, wherein an initial phase difference is set between detection signals of the two sensors.   In both sensors, one end surface in the magnetization direction is applied to the magnetic sensing element arranged with the front surface facing the detection surface of the encoder and the back surface of the magnetic detection element opposite to the detection surface. 2. The apparatus according to claim 1, further comprising a permanent magnet that is in contact with or in close proximity to each other, wherein an initial phase difference is set between detection signals of the two sensors by making the directions of the two sensors different from each other. Rolling bearing unit with displacement measuring device.   An initial phase difference is set between the detection signals of the two sensors by performing arithmetic processing for giving a delay proportional to the rotational speed of the rotating raceway to the output signal of one of the two sensors. Item 2. A rolling bearing unit with a displacement measuring device according to Item 1.   The rolling bearing unit with a displacement measuring device according to claim 1, wherein an initial phase difference is set between detection signals of both sensors by disposing both sensors in the rotational direction of the encoder.   The phase at which the characteristics of the surface to be detected of the encoder change is opposite to each other in the direction parallel to the central axis of the encoder at the portion where the detection portion of one sensor faces and the portion where the detection portion of the other sensor faces. The rolling bearing unit with a displacement measuring device according to any one of claims 1 to 5, wherein the rolling bearing unit is changed in the direction by the same angle.   The phase at which the characteristic of the surface to be detected of the encoder changes is changed only in the part where the detection part of one sensor faces in the direction parallel to the central axis of the encoder, and in the part where the detection part of the other sensor faces. The rolling bearing unit with a displacement measuring device according to any one of claims 1 to 5, wherein the rolling bearing unit is not changed in this direction.   The computing unit has a function of calculating a load acting between the stationary side raceway and the rotation side raceway based on the calculated relative displacement amount, according to any one of claims 1 to 7. Rolling bearing unit with displacement measuring device.   9. The rolling bearing unit is a hub unit for supporting a wheel of an automobile, the stationary side bearing ring is supported by a suspension of the automobile in use, and the wheel is coupled and fixed to a hub that is a rotating side bearing ring. Rolling bearing unit with displacement measuring device described. A rolling bearing unit and a load measuring device;
Of these, the rolling bearing unit is present on a stationary bearing ring that does not rotate even in use, a rotating bearing ring that rotates in use, and circumferential surfaces of the stationary bearing ring and the rotating bearing ring that face each other. A plurality of rolling elements provided between the stationary side track and the rotating side track,
The load measuring device includes an encoder, a pair of sensors, and an arithmetic unit, and the encoder is supported by a part of the rotating side raceway, and the rotating side track The characteristics of the surface to be detected that are concentric with the wheel are alternately changed in the circumferential direction, and the phase at which the characteristics of the surface to be detected changes in the circumferential direction is detected at the part where the detection part of at least one sensor faces. According to the direction of the displacement to be performed, and continuously changing the state in which the detection part of the other sensor is different from the facing part,
The two sensors are supported by a portion that does not rotate in a state in which the respective detection units face the detection surface of the encoder, and change the output signal in response to a change in the characteristics of the detection surface.
In the neutral state where the stationary side raceway and the rotation side raceway are not relatively displaced, an initial phase difference is set between the detection signals of the two sensors,
The computing unit is based on the period of the detection signals of the two sensors and the amount of deviation from the initial phase difference of the actual phase difference existing between the detection signals of the two sensors at each moment. A rolling bearing unit with a load measuring device for calculating a direction and a magnitude of a load acting between the bearing ring and the rotation-side bearing ring.   In both sensors, one end surface in the magnetization direction is applied to the magnetic sensing element arranged with the front surface facing the detection surface of the encoder and the back surface of the magnetic detection element opposite to the detection surface. It is provided with a permanent magnet that is in contact with or in close proximity to each other, and by making the poles of the permanent magnet that are in contact with or in close proximity to the back of the magnetic sensing element between the two sensors different from each other, The rolling bearing unit with a load measuring device according to claim 10, wherein an initial phase difference is set between detection signals of the two sensors.   In both sensors, one end surface in the magnetization direction is applied to the magnetic sensing element arranged with the front surface facing the detection surface of the encoder and the back surface of the magnetic detection element opposite to the detection surface. 11. The apparatus according to claim 10, further comprising a permanent magnet that is in contact with or in close proximity to each other, wherein an initial phase difference is set between detection signals of both sensors by making the directions of the two sensors different from each other. Rolling bearing unit with load measuring device.   An initial phase difference is set between the detection signals of the two sensors by performing arithmetic processing for giving a delay proportional to the rotational speed of the rotating raceway to the output signal of one of the two sensors. Item 11. A rolling bearing unit with a load measuring device according to Item 10.   The rolling bearing unit with a load measuring device according to claim 10, wherein an initial phase difference is set between detection signals of both sensors by disposing both sensors in the rotational direction of the encoder.   The phase at which the characteristics of the surface to be detected of the encoder change is opposite to each other in the direction parallel to the central axis of the encoder at the portion where the detection portion of one sensor faces and the portion where the detection portion of the other sensor faces. The rolling bearing unit with a load measuring device according to any one of claims 10 to 14, wherein the direction is changed by the same angle in the direction.   The phase at which the characteristic of the surface to be detected of the encoder changes is changed only in the part where the detection part of one sensor faces in the direction parallel to the central axis of the encoder, and in the part where the detection part of the other sensor faces. The rolling bearing unit with a load measuring device according to any one of claims 10 to 14, which is not changed in this direction.   The rolling bearing unit is a hub unit for supporting a wheel of an automobile, the stationary side bearing ring is supported by a suspension device of the automobile in use, and the wheel is coupled and fixed to a hub that is a rotating side bearing ring. A rolling bearing unit with a load measuring device according to any one of 16.

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