JP2008157755A - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing which enables compact installation of a load sensor on a vehicle, and accurate detection of a load applied to a wheel. <P>SOLUTION: This wheel bearing 10 with a sensor is equipped with a fixed ring 1 having two rows of rolling surfaces 4A, 4B, a rotating ring 2 having rolling surfaces 5A, 5B opposite to the rolling surfaces 4A, 4B of this fixed ring 1, and a plurality of rows of rolling elements 9A, 9B interposed in between individual opposed rolling surfaces 4A (4B), 5A (5B), and rotatably supports the wheel with respect to the vehicle body. Each of the plurality of rows of elements 9A, 9B is provided with a load detection means 15A, 15B for detecting a change in load by action force between a tire and a road surface or a pre-load amount of the wheel bearing, and a rolling-element phase-difference detection means 16 for calculating the phase difference between the plurality of rows of elements 9A, 9B. Moreover, a correction means 17 is provided for correcting the output signal of the load detection means 15A by the phase difference between the rolling elements found with this detection means 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sensor-equipped wheel bearing with a built-in load sensor for detecting a load applied to a bearing portion of the wheel.

2. Description of the Related Art Conventionally, there is a wheel bearing provided with a sensor for detecting the rotational speed of each wheel for safe driving of an automobile. Conventional measures to ensure driving safety of general automobiles are performed by detecting the rotational speed of the wheels of each part, but the rotational speed of the wheels is not sufficient, and it is further safer by using other sensor signals. It is required that the surface can be controlled.
Therefore, it is conceivable to control the posture from the load acting on each wheel during vehicle travel. For example, a large load is applied to the outer wheel in cornering, and the load applied to each wheel is not uniform. In addition, even when the load is uneven, the load applied to each wheel is uneven. For this reason, if the load applied to the wheel can be detected at any time, the suspension control etc. is controlled in advance based on the detection result, thereby controlling the attitude during vehicle travel (preventing rolling during cornering, preventing the front wheel from sinking during braking, It is possible to prevent subsidence due to uneven load capacity. However, there is no appropriate installation location of a sensor that detects a load acting on the wheel, and it is difficult to realize posture control by load detection.
In addition, when steer-by-wire is introduced in the future and the system becomes a system in which the axle and the steering are not mechanically coupled, it is required to detect the axle direction load and transmit the road surface information to the handle held by the driver.

As a response to such a request, a wheel bearing has been proposed in which a strain gauge is attached to the outer ring of the wheel bearing to detect the strain (for example, Patent Document 1). There has also been proposed a wheel bearing in which an ultrasonic sensor is provided on the outer ring of the wheel bearing and the load is detected based on an echo ratio that varies depending on the contact area between the rolling element and the rolling surface (for example, Patent Document 2).
Special table 2003-530565 gazette JP 2006-145457 A

  However, in the techniques disclosed in Patent Documents 1 and 2, the revolution speed of the double row rolling elements may be different, and the signal value of the detection unit varies due to the phase change between the double row rolling elements, and the load is accurately applied. There is a problem that it cannot be detected. For example, with respect to a case where a vertical load is applied to a tire and the load is detected by a strain gauge attached to the vertical upper surface of the outer ring of the wheel bearing, referring to FIG. 9 and FIG. Will be explained.

9A is an outboard side rolling element row when the phases of the double row rolling elements are the same, and FIG. 9B is an inboard side rolling element row when the phases of the double row rolling elements are the same. FIG. 10A shows the rolling element row on the outboard side when the phase of the double row rolling elements is shifted by P / 2 (P is the rolling element pitch, the same applies hereinafter), and FIG. 10B shows the double row rolling element. The in-board side rolling element row | line | column when the phase of a moving body shifted | deviated by P / 2 is shown.
When the detected value of the strain gauge on the inboard side is compared between FIG. 9 and FIG. 10, since the bearing rigidity on the outboard side is different, the influence of the vertical load on the rolling body on the inboard side changes. As a result, even if the same vertical load is applied, the detected value of the strain gauge is different. Here, the case where the strain is detected has been described, but the same can be said for the case where the contact area between the rolling element and the rolling surface and the relative displacement between the rotating portion and the fixed portion are measured. The same can be said even when the load direction or the detection position changes.

  An object of the present invention is to provide a wheel bearing capable of accurately installing a load sensor on a vehicle and accurately detecting a load applied to the wheel.

The sensor-equipped wheel bearing according to the present invention includes a fixed wheel having a double-row rolling surface, a rotating wheel having a rolling surface facing the rolling surface of the fixed wheel, and each facing rolling surface. In a wheel bearing device comprising a plurality of rolling element rows interposed therebetween and rotatably supporting a wheel relative to a vehicle body, an acting force between a tire and a road surface or a wheel for each of the plurality of rolling element rows Load detecting means for detecting a change in load due to the preload amount of the bearings for rolling, a rolling element phase difference detecting means for calculating a phase difference between a plurality of rolling element rows, and a rolling element phase difference obtained from the rolling element phase difference detecting means And a correction means for correcting the output signal of the load detection means.
According to this configuration, for example, for each of the rolling body rows on the outboard side and the inboard side, for example, a load change due to the acting force between the tire and the road surface is detected by the load detection means, The rolling element phase difference is calculated by the rolling element phase difference detecting means. Since the output signal of the load detecting means is corrected by the correcting means based on the rolling element phase difference obtained from the rolling element phase difference detecting means, it is applied to the wheel regardless of the positional relationship between the rolling elements on the outboard side and the inboard side. The load can be accurately detected.
In addition to the load detection means, the above effect can be obtained only by providing the rolling element phase difference detection means and the correction means, so that the load detection means can be compactly installed in the vehicle.

In this invention, the correction means stores the load detection data based on the phase difference measured in advance or the storage means storing the approximate expression, and the rolling element phase difference obtained from the rolling element phase difference detection means. A correction unit that corrects an output signal of the load detection unit by comparing with load detection data or an approximate expression based on the phase difference stored in the unit may be provided.
As described above, when the load detection data or approximate expression based on the rolling element phase difference measured in advance is stored in the storage means, the output signal of the load detection means based on the rolling element phase difference can be easily corrected. The load can be accurately detected regardless of the phase relationship of the double row rolling elements.

In this invention, the rolling element phase difference detection means may calculate the phase difference of the rolling element row using the output fluctuation when passing through the rolling element in the load detection means.
For example, when a sensor having a large output fluctuation when passing through a rolling element such as an ultrasonic sensor or a strain gauge is used as the load detection means, not only the load but also the position of the rolling element can be detected from the load detection means. A phase difference can be detected.

In this invention, you may further provide the rolling element detection means which detects the position of a rolling element with respect to each of a some rolling element row | line | column.
In the case of this configuration, the position of the rolling element is not detected from the output signal of the load detection means, but is detected by the separately provided rolling element detection means, so that the detection of the rolling element position is facilitated. The rolling element detection means can be a simple sensor having a structure utilizing light, eddy current, etc., and is not required to be accurate, so that it can be installed easily.

  In the present invention, a plurality of each of the rolling element detection means may be provided between the rolling element pitch widths. In the case of this configuration, the time for detecting the position of the rolling element can be shortened.

  The sensor-equipped wheel bearing according to the present invention includes a fixed wheel having a double-row rolling surface, a fixed wheel having a rolling surface facing the rolling surface of the fixed wheel, and each facing rolling surface. In a wheel bearing device comprising a plurality of rolling element rows interposed therebetween and rotatably supporting a wheel relative to a vehicle body, an acting force between a tire and a road surface or a wheel for each of the plurality of rolling element rows Load detecting means for detecting a change in load due to the preload amount of the bearings for rolling, a rolling element phase difference detecting means for calculating a phase difference between a plurality of rolling element rows, and a rolling element phase difference obtained from the rolling element phase difference detecting means Further, since the correcting means for correcting the output signal of the load detecting means is provided, the load sensor can be installed in the vehicle in a compact manner, and the load applied to the wheel can be accurately detected.

An embodiment of the present invention will be described with reference to FIGS. This embodiment is a third generation inner ring rotating type and is applied to a wheel bearing for driving wheel support. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side. In FIG. 1, the left side is the outboard side and the right side is the inboard side.
As shown in FIG. 1, the wheel bearing 10 includes an outer member 1 having double-row rolling surfaces 4A and 4B formed on the inner periphery, and rolling surfaces 5A that face the rolling surfaces 4A and 4B, respectively. , 5B, and the double row rolling elements 3 interposed between the double row rolling surfaces 4A (4B) and 5A (5B). The wheel bearing 10 is a double-row angular ball bearing type, and the rolling elements 3 are formed of balls and are held by a cage 6 for each row. Each of the rolling surfaces 4A to 5B has an arc shape in cross section, and each of the rolling surfaces 4A to 5B is formed so that the ball contact angle is aligned with the back surface. The open end portions on the outboard side and the inboard side of the annular space formed between the inner and outer members 2 and 1 are sealed by contact-type seals 7 and 8 which are sealing devices, respectively.

The outer member 1 is a fixed wheel, and a flange 1a formed on the outer periphery thereof is fastened to a knuckle (not shown) on the vehicle body side with a bolt.
The inner member 2 is a rotating wheel, and includes a hub wheel 2A having a wheel mounting flange 2a on the outer periphery, and a separate inner ring 2B fitted to the outer periphery on the inboard side of the hub wheel 2A. An outer ring 11a, which is one joint member of the constant velocity joint 11, is connected to the hub wheel 2A. Each row of rolling surfaces 5A and 5B is formed on the hub wheel 2A and the inner ring 2B. The hub wheel 2 </ b> A has a center hole 12, and a stem 13 integrally formed with the constant velocity joint outer ring 11 a is inserted into the center hole 12. The joint outer ring 11 a is connected to the inner member 2. At this time, the step surface 11aa facing the outboard provided on the constant velocity joint outer ring 11a is pressed against the end surface facing the inboard side of the inner ring 2B press-fitted into the hub wheel 2A, and the constant velocity joint outer ring 11a and the nut 14 Thus, the inner member 2 is tightened. A spline groove 12a is formed in the center hole 12 of the hub wheel 2A and is fitted to the spline groove 13a of the stem 13 by spline fitting.

  As an example, on the outer peripheral surface of the outer member 1 that is a fixed wheel, load detecting means 15A and 15B for detecting a change in the acting force acting between the tire and the road surface are provided with the row 9A of the rolling elements 3 on the outboard side and the inboards. It is provided for each of the rows 9B of the rolling elements 3 on the board side. Here, the case where the vertical load Fz is detected by the load detection means 15A, 15B out of the acting force between the tire and the road surface is illustrated. Therefore, as shown in FIG. 1 and FIG. 2 showing a front view seen from the inboard side in FIG. 1, the vertical direction (Z-axis direction) of the position of the rolling body row 9A on the outboard side on the outer peripheral surface of the fixed ring 1 ) On the upper side (upper side with respect to the vehicle) and the lower side surface in the vertical direction (lower side with respect to the vehicle). Further, another pair of load detection means 15B, 15B is provided on the upper surface in the vertical direction and the lower surface in the vertical direction at the position of the rolling element row 9B on the inboard side on the outer peripheral surface of the fixed wheel 1. As the load detection means 15A, 15B, for example, a strain gauge or a piezoelectric element that detects a load by converting it into a strain is used. In addition, sectional drawing of the wheel bearing 10 in FIG. 1 shows the IOOI arrow cross section in FIG.

  The load detection means 15A and 15B are connected to a rolling element phase difference detection means 16, and the rolling element phase difference detection means 16 is connected to a correction means 17. FIGS. 5A and 5B show a waveform diagram of an output signal from the inboard load detection means 15B and a waveform diagram of an output signal from the outboard load detection means 15A, respectively.

The rolling element phase difference detection means 16 calculates the phase difference of the rolling elements 3 between the rolling board row 9A on the outboard side and the rolling element row 9B on the inboard side. Specifically, the rolling element phase difference detection means 16 grasps the position of the rolling element 3 in each of the rolling element rows 9A and 9B based on the output fluctuation (FIG. 5) when the load detection means 15A and 15B pass the rolling element. Then, the phase difference of the rolling element 3 is calculated from the time difference of the output signal change between the inboard side and the outboard side. In this calculation, for example, the output signals of the load detection means 15A and 15B are A / D converted to calculate the deviation of the rolling element pitch.
Since the rolling element phase difference is affected by the change in the revolution speed of the rolling element 3 and the slip between the rolling element 3 and the rolling surfaces 4A to 5B, the rolling element phase difference is detected. It is necessary to always grasp the rolling element phase difference by means 16.

  The correcting means 17 corrects, for example, the output signal of the load detecting means 15A from the rolling element phase difference obtained from the rolling element phase difference detecting means 16, so that the position of the rolling element row 9A on the outboard side is corrected. A vertical load Fz is calculated. That is, for example, when measuring the load Fz at the position of the rolling element row 9A at the timing when the rolling element 3 passes the installation position of the load detecting means 15A in the rolling body row 9A on the outboard side, Since the output value of the load detection means 15A varies depending on the position of the rolling element 3 in the rolling element row 9B, the fluctuation is corrected by the correction means 17.

As shown in the block diagram of FIG. 3, the correcting means 17 is load detection data based on the rolling element phase difference measured in advance before the vehicle operation by the user of the vehicle equipped with the sensor-equipped wheel bearing. Is stored as a correction table, and a correction unit 19 that corrects the output signal of the load detection unit 15A.
FIG. 4 shows an example of the correction table in the storage means 18. In this correction table, the row of the load detection values A1, A2, A3,... Of the load detection means 15A for the rolling body row 9A on the outboard side, and the rolling element phase difference values 0 °, 2 °, 4 °, etc. A table is composed of the aligned rows, and the load Fz measured in advance at each phase difference of 0 °, 2 °, 4 °,... Is corrected in the row region corresponding to each load detection value A1, A2, A3,. Each is listed as a value.
The correction unit 19 collates the load detection value of the load detection unit 15A and the rolling element phase difference obtained by the rolling element phase difference detection unit 16 with the correction table of the storage unit 18 to thereby determine the load detection unit 15A. The detected value is corrected. Note that data not described in the correction table (for example, data such as a phase difference of 7.5 ° in the example of FIG. 4) may be calculated by an approximate expression such as linear interpolation.

  For example, assuming that the load detection value of the load detection means 15A is A1 and the rolling element phase difference obtained by the rolling element phase difference detection means 16 is 6 °, the correction unit 19 stores the correction table 19 in the correction table of the storage means 18. The actually measured load value stored at the position where the row of the load detection value A1 and the row having the phase difference of 6 ° intersect is read as a value obtained by correcting the load detection value A1. Thereby, regardless of the positional relationship between the rolling elements 3 on the outboard side and the inboard side, it is possible to accurately detect the load (here, the vertical load Fz) applied to the wheel.

Thus, in this sensor-equipped wheel bearing 10, the load detection means 15A, the change in load due to the acting force between the tire and the road surface is respectively applied to the rolling board rows 9A, 9B on the outboard side and the inboard side. 15B, the rolling element phase difference between the rolling element rows 9A, 9B is calculated by the rolling element phase difference detecting means 16, and the load detection is performed from the rolling element phase difference obtained from the rolling element phase difference detecting means 16. Since the output signal of the means 15A is corrected by the correction means 19, the load (for example, vertical load Fz) applied to the wheels is accurately detected regardless of the positional relationship between the rolling elements 3 on the outboard side and the inboard side. can do.
In addition to the load detection means 15A and 15B, the above effect can be obtained only by providing the rolling element phase difference detection means 16 and the correction means 17, so that the load detection means 15A and 15B can be installed compactly in the vehicle. It is possible to reduce the cost.

  In this embodiment, the correcting means 17 stores the load detection data based on the rolling element phase difference or the approximate expression and the rolling element phase difference obtained from the rolling element phase difference detecting means 16. Since it has the correction | amendment part 19 which collates with the load detection data or approximate expression memorize | stored in the memory | storage means 18, and correct | amends the output signal of the load detection means 15A, it is the load detection means 15A based on a rolling element phase difference. The output signal can be easily corrected, and the load can be accurately detected regardless of the phase relationship of the double row rolling elements 3.

  In this embodiment, strain gauges are used as the load detection means 15A and 15B, and the load is detected by converting it into strain. However, as a detection method other than strain, a rotating part (rotating wheel 2A) and a fixed part (fixed wheel) are used. The relative displacement of 2B) or the contact area between the rolling element 3 and the rolling surfaces 4A to 5B may be detected. A method of detecting a local strain or contact area with an ultrasonic sensor or a strain gauge is particularly effective because the output signal changes greatly when the rolling element 3 passes through the detected portion. Moreover, although two load detection means 15A and 15B were provided up and down with respect to each rolling element row | line 9A and 9B, you may increase the number further.

  Moreover, although this embodiment demonstrated the case where the action force between a tire and a road surface was detected, it is applicable similarly, also when detecting the load by the amount of preload of the wheel bearing 10. FIG.

  6 and 7 show another embodiment of the present invention. This embodiment is a rolling element detection means for detecting the position of the rolling element 3 with respect to each of the rolling board rows 9A and 9B on the outboard side and the inboard side in the sensor-equipped wheel bearing 10 of the previous embodiment. 20A and 20B are further provided. In this case, the rolling element detection means 20A for the rolling body row 9A on the outboard side is shown in FIG. 6 showing a sectional view of the wheel bearing 10, and FIG. 7A showing a sectional view of the rolling body row 9A on the outboard side. Thus, it arrange | positions in the adjacent position by the side of the outboard of rolling-element row | line | column 9A in the upper position in the internal peripheral surface of the outward member 1. FIG. Further, the rolling element detection means 20B for the inboard side rolling element row 9B is shown in FIG. 6 and FIG. 7B showing a sectional view of the inboard side rolling element row 9B. It arrange | positions in the adjacent position by the side of the inboard of rolling-element row | line | column 9B in the upper position in a surface.

  In this embodiment, the rolling element phase difference detection means 16 calculates the rolling element phase difference between the rolling element rows 9A and 9B based on the output signals of the rolling element detection means 20A and 20B. The output signals of the means 15A and 15B may be used in combination. Other configurations are the same as those in the previous embodiment. As the rolling element detection means 20A and 20B, for example, a displacement sensor using light or eddy current can be used, but the detection method is not particularly limited. Further, the number of rolling element detection means 20A and 20B and the installation location are not limited.

  In the case of this embodiment, since the position of the rolling element 3 can be detected not by the output signals of the load detection means 15A and 15B but by the separately provided rolling element detection means 20A and 20B, the position of the rolling element 3 can be easily detected. Become. Further, since the rolling element detection means 20A and 20B can use a simple sensor having a structure utilizing light, eddy current, etc., and accuracy is not required, the installation is easy.

FIG. 8 shows another arrangement example of the rolling element detection means 20A and 20B in the embodiment shown in FIGS. In this example, a plurality of rolling element detection means 20A, 20B are provided between the rolling element pitches for the rolling element rows 9A, 9B on the outboard side and the inboard side. Other configurations are the same as those of the embodiment shown in FIGS.
Thus, by providing a plurality of rolling element detection means 20A, 20B between the rolling element pitches, the time for detecting the position of the rolling element 3 in each of the rolling element rows 9A, 9B can be shortened.

It is a lineblock diagram of the wheel bearing with a sensor concerning one embodiment of this invention. It is the front view which looked at the bearing for the wheels from the inboard side. It is a block diagram which shows schematic structure of the sensor in the wheel bearing. It is a block diagram of an example of the correction table of the memory | storage means in the sensor. It is a wave form diagram of the output signal of the load detection means of the sensor. It is a block diagram of the sensor-equipped wheel bearing which concerns on other embodiment of this invention. (A) is sectional drawing of the example of arrangement | positioning of the rolling element detection means in the rolling body row | line | column on the outboard side in the wheel bearing, (B) is the example of arrangement | positioning of rolling element detection means in the rolling body row | line | column in an inboard side. It is sectional drawing. (A) is sectional drawing of the other example of arrangement | positioning of the rolling-element detection means in the rolling-element row | line | column on the outboard side in the bearing for the wheels, (B) is other rolling-element detection means in the rolling-element row | line | column on the inboard side. It is sectional drawing of the example of arrangement | positioning. It is explanatory drawing in case there is no rolling element phase difference between the rolling element row | line | columns of the outboard side and inboard side in a prior art example. It is explanatory drawing in case there exists a rolling element phase difference between the rolling elements of the outboard side and inboard side in a prior art example.

Explanation of symbols

1. Outer member (fixed ring)
2 ... Inward member (rotating wheel)
3 ... rolling elements 4A, 4B, 5A, 5B ... rolling surfaces 9A, 9B ... rolling element train 10 ... sensor-equipped wheel bearings 15A, 15B ... load detection means 16 ... rolling element phase difference detection means 17 ... correction means 18 ... Storage means 19 ... correction units 20A, 20B ... rolling element detection means

Claims (5)

A stationary wheel having a double row of rolling surfaces, a rotating wheel having a rolling surface opposite to the rolling surface of the fixed wheel, and a plurality of rolling element rows interposed between the opposing rolling surfaces; In the wheel bearing device for supporting the wheel rotatably with respect to the vehicle body,
For each of a plurality of rolling element rows, load detecting means for detecting a change in load due to an acting force between a tire and a road surface or a preload amount of a wheel bearing, and a rolling element for calculating a phase difference between the plurality of rolling element rows A sensor-equipped bearing for a wheel, comprising: a phase difference detection means; and a correction means for correcting an output signal of the load detection means from a rolling element phase difference obtained from the rolling element phase difference detection means.   The correction means according to claim 1, wherein the correction means stores load detection data or approximate expression based on a phase difference, and the rolling element phase difference obtained from the rolling element phase difference detection means is stored in the storage means. A sensor-equipped wheel bearing comprising: a correction unit that corrects an output signal of the load detection means by comparing with load detection data based on a phase difference or an approximate expression.   3. The sensor-equipped wheel bearing according to claim 1 or 2, wherein the rolling element phase difference detecting means calculates a phase difference of the rolling element row by using an output fluctuation when the load detecting means passes through the rolling elements. .   4. The sensor-equipped wheel bearing according to claim 1, further comprising a rolling element detection unit that detects a position of the rolling element for each of the plurality of rolling element arrays. 5. The sensor-equipped wheel bearing according to claim 4, wherein each of the rolling element detection means is provided between the rolling element pitch widths.

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