JP2007225106A - Rolling bearing unit with state quantity measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive rolling bearing unit with a load measurement device. <P>SOLUTION: A cylindrical encoder 4 with magnetic characteristics of a circumferential surface being a detection object surface changed alternately and at equal intervals in a circumferential direction is externally fitted and fixed to an intermediate part of a hub 2. Detection parts of both first and second sensors 7 and 8 respectively supported to an outer wheel 1 are faced to parts, within the circumferential surface of the encoder 4, having circumferential phases different from each other by 180°. Based on the phase difference present between output signals of both the first and second sensors 7 and 8, a radial load in a direction perpendicular to the arrangement direction of both the first and second sensors 7 and 8 is measured in use. By employing such a structure, the above problem is solved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The rolling bearing unit with a state quantity measuring device according to the present invention supports the wheel of a vehicle such as an automobile so as to be rotatable with respect to the suspension device, and measures the magnitude of the load applied to the wheel, thereby stably operating the vehicle. Use to secure. 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 wheel of an automobile is rotatably supported by a rolling bearing unit such as a double-row angular type with respect to a suspension device. In order to ensure the running stability of the automobile, for example, as described in Non-Patent Document 1, an antilock brake system (ABS), a traction control system (TCS), and an electronically controlled vehicle stability A vehicle travel stabilization device such as a control system (ESC) is used. In order to control such various vehicle running stabilization devices, signals representing the rotational speed of the wheels, acceleration in each direction applied to the vehicle body, and the like are required. In order to perform higher-level control, it may be preferable to know the magnitude of a load (for example, one or both of a radial load and an axial load) applied to the rolling bearing unit via a wheel.

  In view of such circumstances, Patent Document 1 discloses a radial applied to a rolling bearing unit based on the revolution speed of a pair of balls constituting a rolling bearing unit which is a double-row angular ball bearing unit. An invention relating to a rolling bearing unit with a state quantity measuring device for measuring a load or an axial load is described. Such a rolling bearing unit with a state quantity measuring device described in Patent Document 1 obtains the revolution speed of the balls in both rows as the rotation speed of a pair of cages holding these balls. Based on the revolution speed of the ball, the radial load or the axial load is calculated. In the case of such a conventional structure, due to a gap inevitably existing between the rolling surface of each ball and the inner surfaces of the pockets of both cages, the revolution speed of the balls in both rows and the both There may be a slight deviation between the rotational speed of the cage. For this reason, in order to obtain | require the said radial load or axial load accurately, there is room for improvement.

On the other hand, as a structure that does not cause such inconvenience related to measurement accuracy, Patent Documents 2 and 3 disclose that a non-contact type displacement sensor supported on an outer ring and a detected ring that is externally fixed to a hub are used to detect the outer ring. A structure is described in which the radial displacement of the hub is measured and the radial load applied to the hub is determined based on the measured value. In the case of such structures described in Patent Documents 2 and 3, since the radial displacement is slight, it is necessary to use a high-precision displacement sensor as the displacement sensor in order to obtain the radial load with high accuracy. There is. However, since a highly accurate non-contact sensor is expensive, it is inevitable that the cost of the entire rolling bearing unit with a state quantity measuring device increases.
In addition, there exists patent document 4 as another prior art document relevant to this invention.

JP 2005-31063 A JP 2001-21577 A Japanese Patent Laid-Open No. 2004-3918 JP 2000-55928 A Motoo Aoyama, “Red Badge Super Illustrated Series / A book that shows the latest mechanics of cars”, p. 138-139, p. 146-149, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001

  The rolling bearing unit with a state quantity measuring device of the present invention has been invented to realize a structure that can sufficiently secure the measurement accuracy of the radial load and can be manufactured at a low cost in view of the above-described circumstances.

Among the rolling bearing units with a state quantity measuring device according to the present invention, the one described in claim 1 includes a rolling bearing unit and a state quantity measuring device.
Of these, the rolling bearing unit has a stationary track on the stationary peripheral surface and does not rotate even when in use, and a rotating track that has a rotating track on the rotating peripheral surface and rotates in use. A ring, and a plurality of rolling elements provided between the stationary track and the rotating track so as to freely roll.
The state quantity measuring device includes an encoder, a sensor device, and a calculator.
Of these, the encoder is supported by a part of the rotating raceway or the rotating member rotating and displacing with the rotating raceway, and has a detected surface concentric with the rotating raceway or the rotating member. . Then, the characteristics of the detected surface are changed alternately and at equal intervals in the circumferential direction, and the boundary lines between the characteristics adjacent to each other in the circumferential direction are parallel to the width direction of the detected surface. .
The sensor device is supported by a portion that does not rotate during use, and includes a plurality of sensors. Each of these sensors has its detection unit opposed to a portion of the detected surface of the encoder that has a different phase in the circumferential direction, and each sensor corresponds to a change in the characteristics of the detected surface. Change the output signal.
The computing unit has a function of calculating a state quantity between the two race rings based on a phase difference existing between output signals of the sensors.
In carrying out the present invention, a surface to be detected is provided on the peripheral surface of the encoder, and the detection portion of each sensor is radially opposed to the surface to be detected, and the side surface of the encoder is covered. Either a configuration in which a detection surface is provided and the detection portion of each sensor is opposed to the detection surface in the axial direction may be employed.

Further, when the rolling bearing unit with a state quantity measuring device described in claim 1 described above is implemented, preferably, as described in claim 2, the state quantity calculated by the computing unit is set for the stationary side race ring. This is the radial displacement of the encoder.
Further, when carrying out the invention described in claim 2, preferably, as described in claim 3, the calculator has a stationary-side bearing ring and a rotating side based on the calculated radial displacement. Provide a function to calculate the radial load applied to the bearing ring.
Alternatively, as described in claim 4, the encoder is a part of a rotating member that rotates and displaces together with the rotating raceway or the rotating raceway, and the center of the rotating raceway and the stationary raceway. The shaft is supported and fixed at a position deviated in the axial direction from the point of intersection when the shafts are inclined to each other (for example, the axial end of the rotating side raceway). At the same time, based on the calculated radial displacement, the calculator adds between the stationary side raceway and the rotation side raceway, a position shifted in the radial direction with respect to the central axis of the stationary side raceway. The function to calculate the axial load input from is provided.

Further, when the rolling bearing unit with a state quantity measuring device described in claim 1 described above is implemented, preferably, as described in claim 5, the state quantity calculated by the computing unit is set as a stationary side ring. Radial load applied to the rotating side raceway.
Alternatively, as described in claim 6, the encoder is a part of a rotating member that rotates and displaces together with the rotating raceway or the rotating raceway, and the center between the rotating raceway and the stationary raceway. It is supported and fixed at a position deviated in the axial direction from the point of intersection when the axes are inclined to each other. At the same time, the state quantity calculated by the calculator is input between the stationary side raceway and the rotation side raceway from a position radially displaced with respect to the central axis of the stationary side raceway. Use axial load.

  Moreover, when implementing the invention described in claims 1 to 6, the configuration described in claim 7 is preferably employed. In the case of the configuration described in claim 7, the sensor device includes three sensors as a plurality of sensors. At the same time, the detection units of these three sensors are opposed to three portions at equal intervals in the circumferential direction of the detection target surface of the encoder.

Moreover, when implementing the invention described in claims 2 to 5, preferably, the configuration described in claim 8 is adopted, and when implementing the invention described in claim 6 above, preferably The configuration described in claim 9 is employed. In the case of the structure described in these claims 8 and 9,
The sensor device includes a first sensor and a second sensor as a plurality of sensors. And the detection part of both these 1st and 2nd sensors is made to oppose the part from which the phase of the circumferential direction differs 180 degree | times among the to-be-detected surfaces of the said encoder.
Furthermore, in the case of the configuration described in claim 8, the computing unit is configured to calculate the first of the radial displacement or the radial load based on the phase difference existing between the output signals of the first and second sensors. The components in the direction perpendicular to the arrangement direction of the detection parts of the first and second sensors (the direction of the straight line connecting the two detection parts) are calculated.
On the other hand, in the case of the configuration described in claim 9, the computing unit determines whether the stationary bearing ring and the rotating bearing ring are based on the phase difference existing between the output signals of the first and second sensors. An axial load input from a position shifted in a direction perpendicular to the direction of arrangement of the detection portions of the first and second sensors with respect to the central axis of the stationary side raceway is calculated.

Moreover, when implementing the invention described in claims 2 to 5 above, preferably, the configuration described in claim 10 is adopted, and when implementing the invention described in claim 6 above, preferably The configuration described in claim 11 is employed. In the case of the structure described in these claims 10 and 11,
The sensor device includes a first sensor and a second sensor, a third sensor and a fourth sensor as a plurality of sensors. And the detection part of both the 1st and 2nd sensors of these is made to oppose the part from which the phase of the circumferential direction differs 180 degree | times among the to-be-detected surfaces of the said encoder. At the same time, the detection portions of the third and fourth sensors are portions of the detected surface of the encoder that are 180 degrees apart from each other in the circumferential direction, and both the first and second sensors. Each of the detection parts is opposed to a part where the circumferential phase is shifted by 90 degrees.
Furthermore, in the case of the structure described in claim 10, the computing unit has first to third functions. Of these, the first function is based on the phase difference existing between the output signals of the first and second sensors, and the state quantity of either one of the radial displacement and the radial load. The component in the direction perpendicular to the arrangement direction of the detection portions of both the first and second sensors is calculated. In the second function, based on the phase difference existing between the output signals of the third and fourth sensors, the detection unit of the third and fourth sensors out of the one state quantity. The component in the direction perpendicular to the arrangement direction is calculated. Furthermore, in the third function, the direction and magnitude of the one state quantity are calculated based on the two perpendicular components calculated by the first and second functions.
On the other hand, in the case of the configuration described in claim 11, the computing unit calculates the phase difference existing between the output signals of the first and second sensors and the output signals of the third and fourth sensors. It has a function of calculating an axial load based on a phase difference existing between them.

  When carrying out the inventions described in the above first to eleventh aspects, preferably, as described in the twelfth aspect, the rolling bearing unit is a hub unit for supporting a wheel of an automobile. 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.

  As described above, according to the rolling bearing unit with the state quantity measuring device of the present invention, based on the phase difference existing between the output signals of the plurality of sensors, the state quantity between the two race rings {for example, The radial displacement of the encoder with respect to the stationary side race (Claim 2), the radial load applied between the two races (Claim 5), and the position shifted in the radial direction with respect to the central axis of the stationary side race An axial load applied between the two race rings (claim 6), etc.} can be calculated. That is, when the radial load or the axial load is applied between the two raceways, the encoder is displaced in the radial direction with respect to the stationary raceway supporting the sensors. Are shifted in different directions or with different magnitudes. As a result, the phase difference existing between the output signals of the sensors changes. The direction and magnitude of this phase difference change correspond to the direction and magnitude of the radial load or the axial load (the radial displacement of the encoder with respect to the stationary wheel). Therefore, if formulas and maps representing the relationship between the two are created in advance by theoretical calculations and experiments, the radial load is calculated based on the direction and magnitude of the change in the phase difference using the formulas and maps. And the acting direction and magnitude of the axial load (the radial displacement of the encoder with respect to the stationary wheel) can be obtained.

  The effects of the present invention will be described more specifically by taking the invention described in claim 8 as an example. According to the eighth aspect of the present invention, the radial load applied between the two race rings (or the stationary race ring) based on the phase difference existing between the output signals of the first and second sensors. Of the encoder in the radial direction) can be calculated in a direction perpendicular to the arrangement direction of the detectors of the first and second sensors. That is, when a radial load is applied between the two race rings, if the radial load includes the perpendicular component, the first and second sensors are The encoder is relatively displaced in the perpendicular direction. As a result, the phases of the output signals of these two sensors are shifted in opposite directions, and the phase difference between the output signals of these two sensors changes accordingly. The direction and magnitude of the change in phase difference correspond to the direction and magnitude of the component in the perpendicular direction (the direction and magnitude of the relative displacement). Therefore, if a formula or a map representing the relationship between the two is created in advance by theoretical calculation or experiment, the perpendicular direction is calculated based on the direction and magnitude of the change in the phase difference using the formula or map. The direction and size of the component can be obtained. In the case of the invention described in claim 8, when the direction of the radial load applied between the two race rings is known in advance (determined in a certain direction), By adopting a configuration in which the perpendicular directions are matched, the direction and magnitude of the radial load can be accurately obtained. The same applies to the invention described in claim 9.

  Further, the effects of the present invention as described above will be described more specifically by taking the invention described in claim 10 as an example. According to the invention described in claim 10, the phase difference existing between the output signals of the first and second sensors and the position existing between the output signals of the third and fourth sensors. Of the radial load (or the radial displacement of the encoder with respect to the stationary side raceway) applied between the two raceways based on the phase difference, it is perpendicular to the direction in which the detectors of the first and second sensors are arranged. The component in the direction and the component in the direction perpendicular to the arrangement direction of the detection units of the third and fourth sensors can be measured. For this reason, even if the direction of the radial load applied between the two races is not known in advance (it is not determined in a certain direction), the radial load (or the stationary side) The direction and magnitude of the encoder's radial displacement relative to the raceway can be accurately determined. The same applies to the case where the action direction and magnitude of the axial load are determined according to the invention described in claim 11.

  In the case of the present invention, as the plurality of sensors and encoders, those similar to the sensors and encoders constituting the rotational speed detection device described in, for example, Patent Document 4 and widely known in the past can be used. . The sensor constituting the rotational speed detection device is less expensive than the non-contact displacement sensor described above. For this reason, in the case of this invention, the cost of a rolling bearing unit with a state quantity measuring device can be suppressed sufficiently. In addition, since the rotational speed of the rotating raceway can be detected based on the output signal of at least one of the plurality of sensors, the rolling is provided with a rotational speed detecting device and a state quantity measuring device. The bearing unit can be realized in a small size and at a low cost.

[First example of embodiment]
1 to 4 show a first example of an embodiment of the present invention corresponding to claims 1, 2, 3, 5, 8, and 12. FIG. The rolling bearing unit with the state quantity measuring device of this example does not rotate while being supported by the suspension device, and rotates together with this wheel while the wheel is supported and fixed to the inner diameter side of the outer ring 1 which is a stationary side race ring. A hub 2 that is a rotation side raceway is rotatably supported via a plurality of rolling elements 3 and 3. Note that a preload is applied to each of the rolling elements 3 and 3 together with contact angles opposite to each other (in the illustrated case, a rear combination type).

  An encoder 4 is externally fitted and fixed between the rolling elements 3 and 3 arranged in a double row at the intermediate portion in the axial direction of the hub 2. The encoder 4 is formed in a cylindrical shape as a whole by a magnetic metal plate such as a mild steel plate, and has slit-like through holes 5 that are long in the axial direction at the intermediate portion in the width direction of the outer peripheral surface, which is a detected surface. 5 and the column parts 6 and 6 are alternately arranged at equal intervals in the circumferential direction. Thereby, the magnetic characteristics of the intermediate portion in the width direction of the outer peripheral surface are changed alternately and at equal intervals in the circumferential direction. As shown in detail in FIG. 2, the boundary between each of the through holes 5 and 5 and the column portions 6 and 6 adjacent to each other in the circumferential direction is the width direction of the detection surface (the encoder 4). Parallel to the axial direction).

  Further, the first sensor 7 and the second sensor 8 are respectively provided at two positions on the opposite side in the radial direction of the portion between the rolling elements 3, 3 arranged in a double row at the axially intermediate portion of the outer ring 1. And is supported and fixed. Each of the first and second sensors 7 and 8 incorporates a permanent magnet and a magnetic detection element such as a Hall IC, Hall element, MR element, and GMR element that constitute a detection unit. The first and second sensors are in a neutral state in which no external force such as a radial load is applied between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are not relatively displaced. The detectors 7 and 8 are placed close to and opposed to two positions (parts whose phases in the circumferential direction differ from each other by 180 degrees) on the opposite side in the radial direction of the intermediate portion in the width direction of the outer peripheral surface of the encoder 4. Note that the vertical direction in FIGS. 1, 3 and 4A does not necessarily represent the vertical direction in the assembled state in the automobile. In other words, when the present embodiment is implemented, the first and second sensors 7 and 8 are mounted on the automobile, as shown in FIGS. 1, 3 and 4A, for example. It can be arranged on both upper and lower sides, or can be arranged on both the left and right sides of the encoder 4.

  When the rolling bearing unit with a state quantity measuring device of this example configured as described above is used, when the encoder 4 rotates together with the wheel supported and fixed to the hub 2, for example, in the direction of arrow A in FIG. The through-holes 5 and 5 and the column portions 6 and 6 formed in the intermediate portion in the width direction of the encoder 4 alternately pass in the vicinity of the detection portions of the first and second sensors 7 and 8, respectively. As a result, the density of the magnetic flux penetrating the detection portions of the first and second sensors 7 and 8 changes, and as shown by the solid line in FIG. Output changes. The frequency at which the outputs of the first and second sensors 7, 8 change in this way is proportional to the rotational speed of the wheel. Therefore, the rotational speed of the wheel can be determined based on the output signal of at least one of the first and second sensors 7 and 8.

  Further, in the case of this example, in the neutral state described above, as shown in FIG. 4A, the column portions 6 and 6 (or the respective through holes 5 and 5) are provided on the detection portion of the first sensor 7. And the timing at which the pillars 6 and 6 (or the through holes 5 and 5) face the detection part of the second sensor 8 coincide with each other. For this reason, in the neutral state described above, the phases of the output signals of the first and second sensors 7 and 8 coincide with each other, as indicated by the solid line in FIG.

On the other hand, between the outer ring 1 and the hub 2 (to the hub 2 that supports and fixes the encoder 4), the arrangement direction of the first and second sensors 7 and 8 {in FIG. 3 and FIG. (A) vertical direction} and a perpendicular direction {the horizontal direction in FIGS. 3 and 4A. For example, when applied the radial load direction} arrow F _R of (A) in FIG. 4, as shown by the broken line in (A) of FIG. 4, the encoder 4 is said first, second double sensor 7, 8 to be displaced in the direction of the arrow F _R. As a result, the timing at which the pillars 6 and 6 (or the through holes 5 and 5) face the detection part of the first sensor 7, and the pillars 6 and 6 to the detection part of the second sensor 8. 6 (or the respective through-holes 5 and 5) face each other in the opposite directions. As a result, as indicated by a broken line in FIG. 4B, the phases of the output signals of the first and second sensors 7 and 8 are shifted in opposite directions. For example, if the displacement of the rotation arrow F _R direction of the arrow b direction are combined, the phase delay of the output signal of the first sensor 7, the phase of the output signal of the second sensor 8 is advanced. A phase difference is generated between the output signals of the first and second sensors 7 and 8 by the sum of the delay and the advance. Here, the direction and magnitude of the phase difference correspond to the direction and magnitude of the radial load (the radial displacement of the encoder 4 with respect to the outer ring 1 that supports the first and second sensors 7 and 8). It will be a thing. Accordingly, the direction and magnitude of the radial load (the radial displacement) can be obtained based on the phase difference. Specifically, when the first and second sensors 7 and 8 are arranged on both the upper and lower sides of the encoder 4 in the assembled state in the automobile, the radial load (radial displacement) in the front-rear direction can be obtained. . If the first and second sensors 7 and 8 are arranged on the left and right sides of the encoder 4, the radial load (radial displacement) in the vertical direction can be obtained.

  In this example, the rotational speed of the wheel and the radial load (the radial displacement) are calculated based on the output signals (frequency and phase difference) of the first and second sensors 7 and 8. The processing to be performed is performed by an arithmetic unit not shown. For this reason, in this computing unit, the frequency and the rotational speed, which have been examined in advance by calculations and experiments based on the elastic contact theory (considering geometric factors such as the shape and dimensions of the detected surface) And the relationship between the phase difference and the radial load (the radial displacement) are incorporated in the form of a calculation formula or a map, respectively. When the present embodiment is implemented, the radial load can be calculated directly from the phase difference, or can be calculated based on the radial displacement after calculating the radial displacement from the phase difference. In this case, the relationship between the radial displacement and the radial load is examined in advance by calculation or experiment, and this relationship is incorporated in the arithmetic unit in the form of a calculation formula or a map. In the case of implementing this example, the computing unit for calculating the rotational speed and the computing unit for calculating the radial load (radial displacement) may be common or may be separate.

  In any case, in the case of this example, the first and second sensors 7 and 8 and the encoder 4 can be the same type of sensors and encoders that constitute a conventionally known rotational speed detection device. . Such first and second sensors 7 and 8 of this example are less expensive than the non-contact displacement sensor described above. For this reason, in the case of this example, the cost of the rolling bearing unit with the state quantity measuring device can be sufficiently suppressed. Further, since the rotational speed of the wheel can also be detected based on the output signals of the first and second sensors 7, 8, the rolling bearing unit having the rotational speed detection device and the state quantity measuring device can be reduced in size and cost. Can be realized.

[Second Example of Embodiment]
Next, FIG. 5 shows a second example of an embodiment of the present invention corresponding to claims 1, 2, 3, 5, 10 and 12. In the case of this example, in addition to the first and second sensors 7 and 8, the third sensor 9 and the fourth sensor 10, each having the same structure as the first and second sensors 7 and 8, respectively. Prepare. And the upper and lower ends of the outer peripheral surface of the encoder 4 in which the detection parts of the first and second sensors 7 and 8 supported on the outer ring 1 (see FIG. 1) are fitted and fixed to the hub 2 (see FIG. 1), respectively. (The portions in which the phases in the circumferential direction are different from each other by 180 degrees) are close to each other. At the same time, the detection parts of the third and fourth sensors 9 and 10 supported by the outer ring 1 are arranged at the left and right end parts of the outer peripheral surface of the encoder 4 (parts whose phases in the circumferential direction are different from each other by 180 degrees). In addition, each of the first and second sensors 7 and 8 is opposed to a portion where the detection portions are opposed to each other, a portion whose phase in the circumferential direction is shifted by 90 degrees.

  In the case of this example configured as described above, when a radial load is applied between the outer ring 1 and the hub 2, it exists between the output signals of the first and second sensors 7, 8. Based on the phase difference, out of the radial load (the radial displacement of the encoder 4 with respect to the outer ring 1), the direction perpendicular to the direction in which the first and second sensors 7, 8 are arranged (the vertical direction in FIG. 5). The component in the left-right direction in FIG. 5 can be measured. At the same time, based on the phase difference existing between the output signals of the third and fourth sensors 9 and 10, the third and fourth sensors 9 out of the radial load (the radial displacement). 10 components can be measured in the arrangement direction (left-right direction in FIG. 5) and in the direction perpendicular to the vertical direction (FIG. 5). For this reason, the direction and magnitude of the radial load (the radial displacement) can be accurately obtained based on these two components in the perpendicular direction (by obtaining the vector sum of these two components). Other configurations and operations are the same as those in the first example of the embodiment described above.

[Third example of embodiment]
Next, FIGS. 6 to 7 show a third example of an embodiment of the present invention corresponding to claims 1, 2, 4, 6, 9, and 12. In the first and second examples described above, the encoder 4 is fitted and fixed to the intermediate portion in the axial direction of the hub 2. On the other hand, in the case of this example, the encoder 4 is externally fitted and fixed to the axially inner end portion (the right end portion in FIG. 6) of the hub 2. And in the outer peripheral surface of the inner half part of the encoder 4 in the axial direction, which is the detected surface, two first positions (portions where the phases in the circumferential direction are 180 degrees different from each other) on the opposite side in the radial direction respectively. The detection parts of the second sensors 7 and 8 are close to each other. In the case of this example, both the first and second sensors 7 and 8 are supported on the inner surface of the cover 11 fixed to the inner end of the outer ring 1. In the case of this example, the first and second sensors 7 and 8 are disposed on the left and right sides of the encoder 4 as shown in FIG. Accordingly, the vertical direction in FIG. 6 is the horizontal direction in the state of assembly to the automobile.

  In the case of a rolling bearing unit for supporting a wheel of an automobile, the axial load applied between the outer ring 1 and the hub 2 is input from the ground contact surface between the outer peripheral surface of the tire and the road surface constituting the wheel coupled and fixed to the hub 2. The Since this ground contact surface exists radially outward (vertically downward) from the center of rotation of the outer ring 1 and the hub 2, the axial load is between the outer ring 1 and the hub 2 as a pure axial load. Rather, it is applied with a moment in a virtual plane (in the vertical direction) including the center axis of the outer ring 1 and the hub 2 and the center of the ground contact surface. When such a moment is applied between the outer ring 1 and the hub 2, the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1. And the center of this inclination (intersection of these two central axes) is a portion between a pair of rolling element rows in the axial direction. For this reason, as the central axis of the hub 2 is inclined with respect to the central axis of the outer ring 1, the encoder 4 supported on the inner end of the hub 2 in the axial direction has both the first and second sensors 7. , 8 are displaced in a direction perpendicular to the arrangement direction of the first and second sensors 7 and 8 {front and back direction in FIG. 6, up and down direction (vertical direction) in FIG. 7}. As a result, as in the case of the first example of the embodiment shown in FIGS. 1 to 4 described above, a phase difference occurs between the output signals of the first and second sensors 7 and 8.

  Here, between this phase difference and the axial load {the radial displacement (vertical displacement) of the encoder 4 with respect to the outer ring 1 or the inclination angle between the central axes}, a wheel bearing rolling bearing unit is provided. There is a predetermined relationship determined by geometrical factors such as the moment stiffness of the surface and the shape and size of the surface to be detected. And this predetermined relationship is calculated | required not only by calculation based on the elastic contact theory and geometry etc. which are known widely in the field of a rolling bearing unit, but also by experiment. Therefore, if an arithmetic unit (not shown) that processes the output signals of the sensors 7 and 8 stores an expression or a map that represents the predetermined relationship, the axial load (the diameter) is calculated based on the phase difference. Directional displacement or tilt angle). Further, if an equation or a map representing the relationship between the radial displacement or the inclination angle and the axial load is stored in the computing unit, the radial displacement or the inclination angle based on the phase difference. Then, the axial load can be obtained based on the radial displacement or the inclination angle.

  In the case of this example as well, when a radial load is applied between the outer ring 1 and the hub 2, the encoder 4 is displaced in the radial direction with respect to the outer ring 1. However, when the encoder 4 is supported and fixed to the inner end of the hub 2 in the axial direction as in this example, the radial displacement of the encoder 4 caused by the axial load is the radial load. Is sufficiently larger than the radial displacement of the encoder 4 caused by the above. For this reason, in the case of this example, the measurement accuracy of the axial load can be secured to a practically sufficient level regardless of the presence of the radial load. Other configurations and operations are the same as those in the first example of the embodiment shown in FIGS.

  Note that the axial load input position in the circumferential direction (the direction in which the encoder 4 is displaced by this axial load) is the same as the rolling bearing unit for supporting a wheel of an automobile, which is the object of the third example of the above-described embodiment. If determined, two sensors (both first and second sensors 7, 8) are arranged in a direction perpendicular to the displacement direction of the encoder 4 as in the third example of the embodiment described above. By doing so, the displacement of the encoder 4 and the axial load can be measured accurately. On the other hand, when the input position of the axial load in the circumferential direction is intended for a rolling bearing unit that changes during operation, the direction in which the encoder 4 is displaced by the axial load also changes during operation. If only two are provided, the displacement of the encoder 4 and the axial load cannot be measured accurately. In this case, for example, as in the structure shown in FIGS. 6 to 7 described above, the encoder 4 is supported and fixed to the axial end of the stationary side race (hub 2) as shown in FIG. Furthermore, a structure (structure described in claim 11) is adopted in which the detection parts of the first to fourth sensors 7 to 10 are opposed to the detection surface of the encoder 4. If such a structure is adopted, it exists between the output signals of the first and second sensors 7 and 8 on the same principle as in the second example of the embodiment shown in FIG. And the direction and magnitude of the radial displacement of the encoder 4 can be accurately obtained based on the phase difference between the output signals of the third and fourth sensors 9 and 10. For this reason, even if the input position of the axial load in the circumferential direction changes during operation, the direction and magnitude of the axial load is determined based on the phase difference or the direction and magnitude of the radial displacement of the encoder 4. Sought exactly.

[Fourth Example of Embodiment]
Next, FIG. 8 shows a fourth example of an embodiment of the present invention corresponding to claims 1, 2, 3, 5, 7 and 12. Also in the case of this example, as shown in FIG. 1 described above, the encoder 4 is externally fixed between the rolling elements 3 and 3 arranged in a double row at the intermediate portion in the axial direction of the hub 2. . At the same time, among the portions between the rolling elements 3, 3 arranged in a double row at the axially intermediate portion of the outer ring 1, the first to third positions are arranged at three positions that are equally spaced in the circumferential direction. Sensors 7, 8, and 9 are supported and fixed. In this state, as shown in FIG. 8, the detection portion of the first sensor 7 is placed at the position of θ = 0 degrees on the outer peripheral surface of the encoder 4 which is the detected surface, and θ = 120 degrees. The detection unit of the second sensor 8 is positioned close to the position, and the detection unit of the third sensor 9 is positioned close to and facing the position θ = 240 degrees. In the case of this example, the external force is not applied between the outer ring 1 and the hub 2, and the first to third sensors 7 are in a neutral state in which the outer ring 1 and the hub 2 are not relatively displaced. , 8 and 9 are regulated such that the phase difference existing between the output signals becomes zero, and the pitch (length in one circumferential direction) P of the characteristic change in the circumferential direction of the detected surface is regulated. (The numbers of the through holes 5, 5 and the column parts 6, 6 are each an integral multiple of 3).

従って、上記各第一〜第三センサ７、８、９に関する自己位相差比ε（０）、ε（１２０）、ε（２４０）は、それぞれ上記（１）式に角度θ＝０度、１２０度、２４０度を代入して、

となる。 In the case of this example configured as described above, a radial load is applied between the outer ring 1 and the hub 2, and this outer ring 1 (detection unit of each of the first to third sensors 7, 8, 9). And the hub 2 (the detected surface of the encoder 4) are displaced relative to each other in the radial direction, the phases of the output signals of the first to third sensors 7, 8, 9 change accordingly. . Here, this phase change amount (self-phase difference) is expressed by a phase-difference ratio (self-phase difference ratio = self-phase difference / 1 period) ε (θ) (θ = 0 degrees, 120 degrees, 240 degrees). To. Also, consider a three-dimensional orthogonal coordinate system in which the front-rear direction axis is the x-axis, the center axis of the outer ring 1 is the y-axis, and the vertical axis is the z-axis in the assembled state in the automobile. The displacement of the encoder 4 with respect to the outer ring 1 in the x-axis direction is x, and the displacement in the z-axis direction is z. In this case, the self-phase difference ratio ε (θ) can be expressed by the following equation (1).

Accordingly, the self-phase difference ratios ε (0), ε (120), and ε (240) related to the first to third sensors 7, 8, and 9 are expressed by the angle θ = 0 °, 120 in the equation (1), respectively. Substituting 240 degrees,

It becomes.

となる。
又、上記第一、第三両センサ７、９の出力信号同士の間に存在する位相差（相互位相差）は、相互位相差比で表すと、

となる。 Therefore, the phase difference (mutual phase difference) existing between the output signals of the first and second sensors 7 and 8 is expressed by a phase difference ratio (mutual phase difference ratio = mutual phase difference / 1 period). ,

It becomes.
Further, the phase difference (mutual phase difference) existing between the output signals of the first and third sensors 7 and 9 is expressed by a mutual phase difference ratio.

It becomes.

となり、これを上記２つの未知数（変位ｘ、ｚ）に就いての式に書き換えると、

となる。この（８）式の右辺中、定数Ｐ（被検出面の円周方向に関する特性変化のピッチ）は、本例の構造により決まる定数である。又、２つの相互位相差比「ε（１２０）−ε（０）」、「ε（２４０）−ε（０）」は、上記第一〜第三センサ７、８、９の出力信号に基づいて求められる。従って、これら第一〜第三センサ７、８、９の出力信号を処理する図示しない演算器に、上記定数Ｐを代入した上記（８）式を記憶させておけば、上記２つの相互位相差比に基づいて、上記２つの未知数（変位ｘ、ｚ）を算出できる。そして、これら２方向変位ｘ、ｚはそれぞれ、上記エンコーダ４の径方向変位のｘ軸方向成分、ｚ軸方向成分であるから、これら両成分に基づいて、上記エンコーダ４の径方向変位の向き及び大きさを求める事ができる。従って、本例の場合も、このエンコーダ４の径方向変位の向き及び大きさに基づいて、前記ラジアル荷重の向き及び大きさを求める事ができる。又、本例の場合も、上記各第一〜第三センサ７、８、９の出力信号同士の間に存在する位相差と上記ラジアル荷重との関係を、弾性接触理論及び幾何学的要因に基づく計算や実験により求め、この関係を計算式やマップの形式で上記演算器に記憶させておけば、上記各位相差から上記ラジアル荷重を直接求める事もできる。 As described above, in the case of the structure of this example, two relational expressions {(5) to (6)} are obtained for two unknowns (displacement x, z). (Displacement x, z) can be obtained analytically. That is, when the two relational expressions {expressions (5) to (6)} are displayed in a matrix,

And rewriting this into the equation for the two unknowns (displacement x, z)

It becomes. In the right side of the equation (8), the constant P (the pitch of the characteristic change in the circumferential direction of the detected surface) is a constant determined by the structure of this example. The two mutual phase difference ratios “ε (120) −ε (0)” and “ε (240) −ε (0)” are based on the output signals of the first to third sensors 7, 8, and 9. Is required. Therefore, if the above equation (8), in which the constant P is substituted, is stored in an arithmetic unit (not shown) that processes the output signals of the first to third sensors 7, 8, and 9, the two mutual phase differences. Based on the ratio, the two unknowns (displacement x, z) can be calculated. Since these two-direction displacements x and z are an x-axis direction component and a z-axis direction component of the radial displacement of the encoder 4, respectively, the direction of the radial displacement of the encoder 4 and the The size can be determined. Therefore, also in this example, the direction and magnitude of the radial load can be obtained based on the direction and magnitude of the radial displacement of the encoder 4. Also in this example, the relationship between the phase difference existing between the output signals of the first to third sensors 7, 8, 9 and the radial load is based on the elastic contact theory and geometric factors. If the relationship is obtained by calculation or experiment based on this relationship, and the relationship is stored in the computing unit in the form of a calculation formula or a map, the radial load can be directly obtained from the phase differences.

  In the fourth example of the embodiment described above, a configuration is adopted in which the encoder 4 and the first to third sensors 7, 8, 9 are arranged in the intermediate portion in the axial direction of the outer ring 1 and the hub 2. On the other hand, a configuration (configuration described in claims 4 and 6) in which the encoder 4 and the first to third sensors 7, 8, and 9 are arranged at the inner ends in the axial direction of the outer ring 1 and the hub 2 is adopted. Then, based on the phase difference existing between the output signals of the first to third sensors 7, 8, 9 (or the radial displacement of the encoder 4 calculated from these phase differences), the contact described above is performed. An axial load that is input from the ground and applied between the outer ring 1 and the hub 2 can be obtained.

となる。従って、上記第一、第二両センサの出力信号同士の間に存在する位相差（相互位相差）は、位相差比（相互位相差比＝相互位相差／１周期）で表すと、

となる。従って、外輪１（図１参照）に対する上記エンコーダ４の変位ｘは、次の（１２）式で表す事ができる。

Further, the calculation formulas for obtaining the displacements x and z shown in the fourth example of the embodiment described above can be derived with other structures. For example, when the positional relationship between the three-dimensional coordinates (x, y, z) and the encoder 4 is set as shown in FIG. 8, the position of θ = 0 degrees on the outer peripheral surface of the encoder 4 (the lower end of FIG. 8). Consider the structure in which the detection unit of the first sensor is close to the position of the first sensor and the detection unit of the second sensor is close to the position θ = 180 degrees (the upper end portion in FIG. 8). In the case of this structure, the self-phase difference ratio ε (0) of the output signals of both the first and second sensors, which occurs when the encoder 4 is displaced in the x-axis direction with respect to the first and second sensors. , Ε (180) are obtained by substituting the angles θ = 0 ° and 180 ° into the equation (1), respectively.

It becomes. Therefore, the phase difference (mutual phase difference) existing between the output signals of the first and second sensors is expressed by a phase difference ratio (mutual phase difference ratio = mutual phase difference / 1 period).

It becomes. Therefore, the displacement x of the encoder 4 with respect to the outer ring 1 (see FIG. 1) can be expressed by the following equation (12).

となる。従って、上記第一、第二両センサの出力信号同士の間に存在する位相差（相互位相差）は、位相差比（相互位相差比＝相互位相差／１周期）で表すと、

となる。従って、外輪１（図１参照）に対する上記エンコーダ４の変位ｚは、次の（１６）式で表す事ができる。

Similarly, when the positional relationship between the three-dimensional coordinates (x, y, z) and the encoder 4 is set as shown in FIG. 8, the position of θ = 90 degrees on the outer peripheral surface of the encoder 4 (FIG. 8). Let us consider a structure in which the detection unit of the first sensor is positioned close to the left end of the second sensor and the detection unit of the second sensor is positioned close to each other at a position of θ = 270 degrees (the right end of FIG. 8). In the case of this structure, the self-phase difference ratio ε (0) of the output signals of both the first and second sensors, which occurs when the encoder 4 is displaced in the z-axis direction with respect to the first and second sensors. , Ε (180) are obtained by substituting the angle θ = 90 degrees and 270 degrees into the equation (1), respectively.

It becomes. Therefore, the phase difference (mutual phase difference) existing between the output signals of the first and second sensors is expressed by a phase difference ratio (mutual phase difference ratio = mutual phase difference / 1 period).

It becomes. Therefore, the displacement z of the encoder 4 with respect to the outer ring 1 (see FIG. 1) can be expressed by the following equation (16).

  In the case of carrying out the present invention, when the encoder is made of a simple magnetic material, as a configuration of the detection surface of the encoder, in addition to the configuration in which the through holes and the column portions are alternately arranged in the circumferential direction, For example, the structure which arrange | positions a recessed part and a convex part alternately with respect to the circumferential direction is also employable. It is also possible to adopt a configuration in which the encoder is made of a permanent magnet, and the north and south poles are alternately arranged on the detected surface of the encoder in the circumferential direction. In this way, when the encoder is made of a permanent magnet, it is not necessary to incorporate permanent magnets on the plurality of sensors constituting the sensor device. The encoder incorporated in the present invention is not limited to an encoder having a detected surface on the peripheral surface, and an encoder 4a having a detected surface on a side surface as shown in FIG. 9, for example, can also be used. As described above, when the encoder 4a having the detection surface on the side surface is used, as shown in FIG. 9, a plurality of sensors constituting the sensor device (both the first and second sensors in the illustrated example). The detection units 7 and 8) are opposed to the detected surface in the axial direction.

  The rolling bearing unit with a state quantity measuring device of the present invention is not limited to a rolling bearing unit for supporting wheels of a vehicle, but can be applied to a rolling bearing unit incorporated in a rotating support portion of various mechanical devices. In addition, the present invention can be configured by adding a necessary number of sensors to a rotating machine (for example, the above-described rolling bearing unit with a rotational speed detection device) that already includes an encoder that is a component of the present invention. . In this case, since the encoder already provided in the rotary machine can be used as it is, it is not necessary to change the design of the rotary machine with respect to the encoder portion.

Sectional drawing which shows the 1st example of embodiment of this invention. The perspective view of an encoder. FIG. 2 is a schematic view corresponding to the AA cross section of FIG. 1, showing only the encoder and the first and second sensors. (A) is a schematic diagram similar to FIG. 3, and (B) is a diagram for explaining a state in which the output signals of both the first and second sensors change based on the radial load. The schematic diagram similar to FIG. 3 which shows the 2nd example of embodiment of this invention. Sectional drawing which shows the 3rd example. FIG. 7 is a schematic view corresponding to the BB cross section of FIG. 6, showing only the encoder and the first and second sensors. The schematic diagram similar to FIG. 3 which shows the 4th example of embodiment of this invention. The figure which looked from the axial direction which shows the encoder which can be employ | adopted when implementing this invention and which provided the to-be-detected surface with the sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling element 4 Encoder 5 Through-hole 6 Column part 7 First sensor 8 Second sensor 9 Third sensor 10 Fourth sensor 11 Cover

Claims (12)

A rolling bearing unit and a state quantity measuring device;
Among these, the rolling bearing unit has a stationary side raceway on the stationary side circumferential surface and does not rotate even when used, and a stationary side raceway that has a rotational side raceway on the rotational side circumferential surface and rotates when used. A ring, and a plurality of rolling elements provided between the stationary-side track and the rotating-side track so as to roll freely,
The state quantity measuring device includes an encoder, a sensor device, and a calculator.
Of these, the encoder is supported on a part of the rotating raceway or the rotating member that rotates and displaces with the rotating raceway, and has a detected surface concentric with the rotating raceway or the rotating member. The characteristics of the detected surface are changed alternately and at equal intervals in the circumferential direction, and the boundary lines between the characteristics adjacent in the circumferential direction are parallel to the width direction of the detected surface, respectively. Is,
The sensor device is supported by a portion that does not rotate during use, and includes a plurality of sensors. Each of these sensors has a detection unit having a phase in a circumferential direction on a detection surface of the encoder. It is opposed to different parts, and each output signal is changed in response to the characteristic change of the detected surface,
The arithmetic unit has a function of calculating a state quantity between the two race rings based on a phase difference existing between output signals of the sensors.
Rolling bearing unit with state quantity measuring device.   The rolling bearing unit with a state quantity measuring device according to claim 1, wherein the state quantity calculated by the computing unit is a radial displacement of the encoder with respect to the stationary side race.   The rolling bearing unit with a state quantity measuring device according to claim 2, wherein the arithmetic unit has a function of calculating a radial load applied between the stationary side raceway and the rotation side raceway based on the calculated radial displacement. . From the point where the encoder intersects with the rotation-side raceway or a part of the rotating member that rotates and displaces together with the rotation-side raceway, and the central axes of the rotation-side raceway and the stationary-side raceway are inclined to each other. It is supported and fixed at a position deviated in the axial direction,
Based on the calculated radial displacement, an arithmetic unit is input from a position that is added between the stationary side raceway and the rotation side raceway and that is radially displaced with respect to the central axis of the stationary side raceway. Has a function to calculate the axial load,
A rolling bearing unit with a state quantity measuring device according to claim 2.   The rolling bearing unit with a state quantity measuring device according to claim 1, wherein the state quantity calculated by the computing unit is a radial load applied between the stationary side bearing ring and the rotating side bearing ring. From the point where the encoder intersects with the rotation-side raceway or a part of the rotating member that rotates and displaces together with the rotation-side raceway, and the central axes of the rotation-side raceway and the stationary-side raceway are inclined to each other. It is supported and fixed at a position deviated in the axial direction,
The state quantity calculated by the computing unit is an axial load applied between the stationary side raceway and the rotation side raceway, which is input from a position shifted in the radial direction with respect to the central axis of the stationary side raceway. is there,
A rolling bearing unit with a state quantity measuring device according to claim 1.   The sensor device includes three sensors as a plurality of sensors, and the detection units of the three sensors are opposed to three positions at equal intervals in the circumferential direction of the detection target surface of the encoder. The rolling bearing unit with a state quantity measuring device described in any one of 1-6. The sensor device includes a first sensor and a second sensor as a plurality of sensors, and the detection units of both the first and second sensors are arranged so that their phases in the circumferential direction are out of the detected surfaces of the encoder. It faces the part that is 180 degrees different,
The arithmetic unit is arranged based on the phase difference existing between the output signals of the first and second sensors, and the detectors of the first and second sensors are arranged in the radial displacement or radial load. Calculate the component perpendicular to the direction,
The rolling bearing unit with a state quantity measuring device according to any one of claims 2 to 5. The sensor device includes a first sensor and a second sensor as a plurality of sensors, and the detection units of both the first and second sensors are arranged so that their phases in the circumferential direction are out of the detected surfaces of the encoder. It faces the part that is 180 degrees different,
The computing unit is a central axis of the stationary side raceway that is added between the stationary side raceway and the rotation side raceway based on the phase difference existing between the output signals of the first and second sensors. The axial load input from a position shifted in a direction perpendicular to the direction of arrangement of the detection units of the first and second sensors is calculated.
A rolling bearing unit with a state quantity measuring device according to claim 6. The sensor device includes a first sensor, a second sensor, a third sensor, and a fourth sensor as a plurality of sensors, and the detection units of both the first and second sensors are detected by the encoder. The surfaces of the third and fourth sensors are opposed to portions of the surface that are 180 ° different from each other in the circumferential direction, and the phases in the circumferential direction of the detected surfaces of the encoder are 180 °. It is a portion that is different from each other and is opposed to a portion in which the phase in the circumferential direction is shifted by 90 degrees with respect to the portion that faces the detection portions of the first and second sensors,
Based on the phase difference that exists between the output signals of the first and second sensors, the computing unit is the first of the state quantities of radial displacement and radial load. Based on the first function for calculating the component in the direction perpendicular to the arrangement direction of the detection portions of the second both sensors and the phase difference existing between the output signals of the third and fourth sensors, Of the state quantities of the second and second sensors, the second function for calculating a component in the direction perpendicular to the arrangement direction of the detection units of the third and fourth sensors, and the two functions calculated by the first and second functions. A third function for calculating the direction and magnitude of the one state quantity based on two perpendicular components;
The rolling bearing unit with a state quantity measuring device according to any one of claims 2 to 5. The sensor device includes a first sensor, a second sensor, a third sensor, and a fourth sensor as a plurality of sensors, and the detection units of both the first and second sensors are detected by the encoder. The surfaces of the third and fourth sensors are opposed to portions of the surface that are 180 ° different from each other in the circumferential direction, and the phases in the circumferential direction of the detected surfaces of the encoder are 180 °. It is a portion that is different from each other and is opposed to a portion in which the phase in the circumferential direction is shifted by 90 degrees with respect to the portion that faces the detection portions of the first and second sensors,
The arithmetic unit is based on the phase difference existing between the output signals of the first and second sensors and the phase difference existing between the output signals of the third and fourth sensors. Has a function to calculate the load,
A rolling bearing unit with a state quantity measuring device according to claim 6.   The rolling bearing unit is a hub unit for supporting a wheel of an automobile, and the stationary-side bearing ring is supported by the suspension device of the automobile in use, and the wheel is coupled and fixed to the hub that is the rotating-side bearing ring. The rolling bearing unit with a state quantity measuring device according to any one of claims 1 to 11.

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