JP4866684B2 - Rolling bearing device for wheels - Google Patents

Description

  The present invention relates to a wheel rolling bearing device.

In recent years, in automobiles, ABS control for preventing wheel lock during braking, traction control for suppressing spin of driving wheels, control for suppressing side slip at cornering, and the like are performed. Conventionally, there is a means for performing these controls by detecting the rotational speed of the wheel with a sensor. However, in this case, the obtained data is inaccurate, and the post-control is performed in which the wheel slips and the rotational speed increases to detect the change.
In order to improve control accuracy and perform control before slipping or the like, for example, as in Patent Document 1, a rolling bearing device (hub unit) to which a wheel is attached is provided with a sensor, and the wheel ground load is applied to the rolling bearing. A configuration for detecting in an apparatus has been proposed. This rolling bearing device includes an outer ring fixed to the vehicle body side, an inner shaft to which the wheel is attached, and a load sensor that measures a load between a pair of radially facing inner walls formed on the outer ring. Yes.
This load sensor is a ceramic sensor capable of measuring a load (displacement) only in one compression direction, and is provided in a state sandwiched between inner walls in a slit. Then, a load is applied to the rolling bearing device, and the space between the inner walls of the slit is displaced, so that the load is detected from the displacement by the sensor. Further, in order to measure the load in both positive and negative (tensile compression) directions by this sensor, the sensor is accommodated in the slit in a state where a preload (preload) is applied.

Japanese Patent Laid-Open No. 2004-360782

In such a rolling bearing device, when the wheel side rotates, the temperature of the rolling bearing device rises due to friction in the rolling elements. When heat due to friction is transmitted to the flange portion of the outer ring, a radial temperature gradient occurs in the flange portion. As a result, a temperature difference occurs between the radially inner side and the outer side of the slit formed in the flange portion, the amount of deformation differs between the radially inner side and the outer side of the slit, and the distance between the inner walls of the slit (slit width) changes. Resulting in.
Therefore, the sensor housed in the slit between the inner walls has a constant distance between the inner walls of the slit due to this temperature difference even if the load acting on the rolling bearing device (outer ring) is constant. There is a problem that the output of the sensor changes and a temperature drift occurs.

  The present invention has been made in view of the above problems, and an object thereof is to provide a wheel rolling bearing device with a sensor capable of suppressing the influence of a sensor output caused by a temperature difference between vehicle body side track members. .

  In order to achieve the above object, a rolling bearing device for a wheel according to the present invention includes a vehicle body side race member fixed to the vehicle body side, a wheel side race member to which a wheel is attached, and a roll between these race members. In the rolling bearing device for a wheel provided with the interposed double row rolling elements and a sensor device for obtaining a load applied to the vehicle body side raceway member, the sensor device is formed on the vehicle body side raceway member. A load sensor for measuring a load between a pair of inner walls facing each other in a radial direction, and a temperature difference between the inner walls to correct an output of the load sensor including an output caused by a temperature difference between the inner walls. And a temperature sensor for measuring the temperature.

  According to such a configuration, the temperature of the vehicle body side track member rises due to friction caused by rolling of the rolling elements, and a temperature difference is generated between the pair of inner walls facing in the radial direction. Even if the distance changes and an output due to the temperature difference is added to the sensor output of the load sensor, the sensor output of the load sensor can be corrected by using the measurement result of the temperature sensor. Thereby, the sensor output by the load actually acting on the vehicle body side track member can be obtained.

  Moreover, it is preferable that the said sensor apparatus is connected to the correction | amendment calculating part which correct | amends the output of the said load sensor using the measurement result of the said temperature sensor. Thereby, the output of the load sensor can be corrected.

In this case, it is preferable that the correction calculation unit has correction data in which a relationship between a temperature difference between the inner walls and an output generated in the load sensor due to the temperature difference is obtained in advance.
According to this, the temperature difference between the inner walls can be detected by the temperature sensor, and the sensor output generated by the temperature difference can be easily obtained based on the correction data by the correction calculation unit. Then, by subtracting the sensor output caused by this temperature difference from the output by the load sensor, the sensor output by the load actually acting on the vehicle body side track member can be obtained.

  In addition, a fixing flange portion for fixing the vehicle body side track member to the vehicle body side mounting member extends radially outwardly and is integrally formed with the vehicle body side track member, and the pair of inner walls includes the pair of inner walls An axial measurement position of each load sensor on each of the pair of inner walls is formed at an intermediate position in the axial direction of the rolling elements in a double row, respectively formed at the upper part, the lower part, the horizontal front part, and the horizontal rear part of the fixed flange part. It is preferable.

According to this configuration, the load acting on the fixed flange portion causes a displacement between the pair of inner walls of the upper and lower portions in the radial direction, which can be measured by the upper load sensor and the lower load sensor. The load can be determined. In addition, the load acting on the fixed flange portion causes a radial displacement between the pair of inner walls of the front and rear portions, which can be measured by the front load sensor and the rear load sensor. Can be requested. Further, since the axial load acting on the wheel acts on the rolling bearing device as a moment centering on the horizontal line in the front-rear direction, the axial load can be obtained by the upper load sensor and the lower load sensor.
In addition, since the measurement position in the axial direction of each sensor is an intermediate position of the double row rolling elements, the load transmitted from the wheel side race member to the vehicle body side race member via the double row rolling elements is It can be made to act on each load sensor equally from both rolling elements. Thereby, it is possible to cancel load components other than the direction intended for detection in each load sensor, and to improve detection accuracy. And the influence of the sensor output by a temperature difference can be suppressed, and an accurate load can be detected.

  The vertical direction is the vertical direction (Z direction) of the vehicle in a state where the wheel rolling bearing is attached to the vehicle body. The horizontal front-rear direction is a direction orthogonal to the vertical direction, and is the traveling and retreating direction (X direction) of the vehicle. The axial direction is a horizontal direction orthogonal to the up-down direction and the horizontal front-rear direction, and is the left-right direction (Y direction) of the vehicle.

  According to the rolling bearing device for a wheel of the present invention, it is possible to suppress the influence of the output given to the load sensor due to the temperature difference of the vehicle body side raceway member. The load actually acting on the rolling bearing device for the wheel can be accurately detected by the ground contact load of the wheel.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of a rolling bearing device for a wheel (hereinafter also simply referred to as a bearing device) according to the present invention, and FIG. 2 is a view of the bearing device as viewed from the axial direction. The bearing device is used for a wheel of a vehicle such as an automobile, and has an inner shaft 1 having a flange portion 4 to which a wheel side member 5 is attached at an outer side (outer) end portion 10, and a diameter of the inner shaft 1. An outer ring 2 that is provided outward in the direction and is fixed to the vehicle body side is provided. In addition, as the wheel side member 5 attached to the flange part 4, there are a wheel wheel and a brake rotor for disc brake, which are attached by bolts 12.
An inner ring member 14 is externally fitted and attached to the inner side (inner side) end portion 11 of the inner shaft 1. The outer ring 2 is provided radially outward of the inner shaft 1 and the inner ring member 14 with two rows of rolling elements 3a and 3b interposed.

A small-diameter portion 27 for externally fitting the inner ring member 14 is formed at the inner side end portion 11 of the inner shaft 1. An annular stepped surface (butting surface) 28 is formed on the axial outer side of the small diameter portion 27, and a medium diameter portion 29 is formed from the outer peripheral edge of the stepped surface 28 toward the axial outer side. Yes. A large-diameter portion 30 is formed on the further axial outer side of the medium-diameter portion 29, and an outer peripheral surface of the large-diameter portion 30 is a seal surface of a seal member 13 provided between the inner shaft 1 and the outer ring 2. ing.
The inner ring member 14 is attached to the inner shaft 1 by being fitted on the small diameter portion 27 of the inner shaft 1 and abutted against the stepped surface 28. The inner ring member 14 is sandwiched between a nut member 15 and a stepped surface 28 that are screwed into a threaded portion formed at the inner side end 11 of the inner shaft 1. Compressed and fixed. A cover member 21 is attached to the inner side end of the outer ring 2. FIG. 2 shows a state where the cover member 21 is removed.

A single raceway surface for the inner-side first rolling element 3 a is formed on the outer peripheral surface of the inner ring member 14. A single raceway surface for the outer-side second rolling element 3b is formed on the outer peripheral surface of the inner diameter portion 29 of the inner shaft 1. The first and second rolling elements 3a and 3b may be tapered rollers other than the balls shown in FIG.
The outer ring 2 is provided so as to be coaxial with the inner shaft 1, and the outer ring 2 has a cylindrical portion 16 and a fixed flange portion 17. Two rows of raceway surfaces for the first and second rolling elements 3 a and 3 b are formed on the inner peripheral surface of the cylindrical portion 16. The two rows of the first and second rolling elements 3a and 3b are allowed to roll between the inner and outer raceways.

The fixed flange portion 17 of the outer ring 2 is provided on the outer peripheral surface side of the cylindrical portion 16. The fixed flange portion 17 is formed to extend radially outward from the cylindrical portion 16 and is fixed to an attachment member (knuckle) 18 provided on the vehicle body side. Therefore, the bearing device is fixed to the vehicle body side by connecting the fixing flange portion 17 to the mounting member 18 on the vehicle body side.
In the bearing device of FIGS. 1 and 2, the outer ring 2 is a vehicle body side track member fixed to the vehicle body side, and the inner shaft 1 and the inner ring member 14 fitted on the outer shaft 2 are wheel side track members. . By fixing this bearing device to the vehicle body side of the automobile, the flange portion 4 side of the inner shaft 1 becomes the outer side, and the inner ring member 14 side fitted on the inner shaft 1 becomes the inner side.

  The bearing device further includes a sensor device 6 for obtaining a load acting on the bearing device. The sensor device 6 has a load sensor 19 and a temperature sensor 20. The load sensor 19 is a sensor for measuring the load between the pair of inner walls 8 and 9 facing the radial direction of the slit 7 formed in the outer ring 2. The temperature sensor 20 is a sensor that measures a temperature difference Δt between the inner walls 8 and 9. That is, the load sensor 19 and the temperature sensor 20 are provided on the outer ring 2 side, and this bearing device has the outer ring 2 via the inner shaft 1, the inner ring member 14, and the rolling elements 3a and 3b that rotate the ground load of the wheel. Is to be detected.

The slit 7 is formed in the fixed flange portion 17 of the outer ring 2, and slits 7 a, 7 b, 7 c, 7 d (hereinafter referred to as “slit 7”) are respectively formed in the upper portion, the lower portion, the horizontal front portion, and the horizontal rear portion of the fixed flange portion 17. Also called). The slit 7 is formed such that the thickness direction of the fixed flange portion 17 is the depth direction, and a pair of radially outer inner walls 8 and radially inner walls 9 facing each other in the radial direction in each slit 7. Is formed. A pair of inner walls 8 and 9 in each of the upper and lower slits 7a and 7b form an inner surface orthogonal to a vertical plane passing through the axis C. A pair of inner walls 8 and 9 in each of the front and rear slits 7c and 7d form an inner surface orthogonal to a horizontal plane passing through the axis C. These slits 7 are provided in the fixed flange portion 17 at intervals of 90 °.
The slit 7 may be a straight through hole that opens to both the inner flange surface 17a and the outer flange surface 17b of the fixed flange portion 17, or is not shown, but is open to only one of the surfaces. It may be the bottom hole.

Further, load sensors 19a, 19b, 19c and 19d (hereinafter also referred to as load sensors 19) and temperature sensors 20a, 20b, 20c and 20d (hereinafter referred to as “load sensors 19”) are provided in the slits 7a, 7b, 7c and 7d, respectively. , Each of which is also referred to as a temperature sensor 20).
The load sensor 19 shown in FIGS. 1 and 2 is provided inside the slit 7 between the inner walls 8 and 9, and the radial load can be obtained from the radial displacement between the inner walls 8 and 9. it can. The temperature sensor 20 detects a temperature difference Δt between the inner wall 8 on the radially outer side of the slit 7 and the inner wall 9 on the inner side.

The load sensor 19 can be, for example, a sensor that can detect a load in only one compression direction. And this load sensor 19 is accommodated in the state which was pinched | interposed between the inner walls 8 and 9 of the slit 7, and the preload was given. By applying a preload to the load sensor 19, it is possible to detect a load in two directions, positive and negative (tensile and compressed).
The upper and lower slits 7a and 7b can be deformed in a direction in which the pair of facing inner walls 8 and 9 approach or separate in the vertical direction, respectively, and the upper and lower load sensors 19a and 19b are provided in each slit 7a. , 7b, the load can be measured from the displacement in the direction between the inner walls 8,9.
The front and rear slits 7c and 7d can be deformed in a direction in which the pair of facing inner walls 8 and 9 approach or separate in the horizontal front-rear direction, and the front and rear sensors 19c and 19d The load can be measured from the displacement in the direction of the inner walls 8 and 9 at 7c and 7d. Note that the type of the load sensor 19 may be other than a contact type sensor (displacement sensor). For example, the load sensor 19 is attached to the radially outer wall 8 so that the measuring portion faces the radially inner wall 9. A non-contact type displacement sensor may be used.

  The temperature sensor 20 can be a thermocouple, and detects a temperature difference Δt between the radially inner wall 8 and the inner wall 9 of the slit 7. The contact (measurement unit) which is the tip of the thermocouple is inserted into a small hole formed in each of the inner walls 8 and 9, and the temperature at the center of the fixing flange 17 in the thickness direction is measured. Yes. The thermocouple may be inserted from the mounting member 18 side on the vehicle body side or may be inserted from the opposite outer side. The position of the tip portion of the temperature sensor 20 is set in the vicinity of the load sensor 19, and the tip portion of the thermocouple is embedded in the fixed flange portion 17. When the thermocouple is inserted from the mounting member 18 side on the vehicle body side, a small hole is formed in the mounting member 18, and the thermocouple passes through the hole. Furthermore, a plurality of sets of temperature sensors 20 for measuring the temperature difference Δt between the inner wall 8 on the radially outer side of the slit 7 and the inner wall 9 on the inner side may be provided in one slit 7.

Further, the sensor device 6 is connected to a correction calculation unit 22 that corrects the output of the load sensor 19 using the measurement result of the temperature sensor 20. In other words, the correction calculation unit 22 is connected to the load sensor 19 and the temperature sensor 20, and the correction calculation unit 22 uses the measurement result of the temperature sensor 20 as shown in the block diagram of FIG. The output of the load sensor 19 including the output generated by the temperature difference Δt is corrected. The correction calculation unit 22 can be configured by a microcomputer (for example, ECU) mounted on the vehicle body side.
When the wheel-side track member rotates, heat is generated by friction in the rolling elements 3a and 3b, and the heat is transmitted to the fixed flange portion 17 of the outer ring 2, where the inner diameter side portion is hot and the outer diameter side portion is low temperature. A temperature gradient is generated. As a result, a temperature difference Δt is generated between the inner wall 8 on the radially outer side of the slit 7 and the inner wall 9, and the amount of deformation of each of the inner walls 8, 9 is different, resulting in a distance (slit width) between the inner walls 8, 9. It will change compared to before the temperature rise. For this reason, even if the wheel ground load in the bearing device is constant, an output is generated in the load sensor 19 due to this temperature difference Δt.
However, the sensor device 6 according to the present invention outputs the sensor output of the load sensor 19 based on the measurement result (temperature difference Δt) of the temperature sensor 20 even if the output of the temperature sensor Δt is added to the output of the load sensor 19. By correcting, it is possible to obtain the sensor output due to the load actually acting on the wheel rolling bearing device.

  The correction calculation unit 22 is correction data obtained in advance for the relationship between the temperature difference Δt between the inner walls 8 and 9 facing each slit 7 and the output generated in the load sensor 19 of the slit 7 by the temperature difference Δt. have. The correction data is data obtained by measuring in advance with a bearing device provided with the sensor device 6. A load is applied to the bearing device, and the temperature sensor 20 causes a temperature difference between the inner walls 8 and 9 in each slit 7. The relationship between Δt and the output value of the load sensor 19 when the temperature difference Δt occurs is measured in advance. This correction data is obtained by changing the temperature difference Δt by increasing or decreasing the number of revolutions in the bearing device.

The correction data will be specifically described.
FIG. 4 shows the temperature inside and outside the slit 7 measured by the temperature sensor 20 when the wheel rolling bearing device according to the embodiment shown in FIGS. 1 and 2 is rotated by applying a constant load. The relationship between the inner temperature is an arrow a, the outer temperature is an arrow b), and the output of the load sensor 19 (arrow c) is shown.
When a vertical load (5 kN) and an axial load (10 kN) are applied to the bearing device after the measurement is started, the initial output of the load sensor 19 is about 180 N. When the wheel side was rotated at 800 rpm in this state (equivalent to 100 km / h traveling), the temperature inside and outside the slit 7 was almost the same at 36 ° C. before the rotation, but the inside (arrow a) was outside ( The temperature rises more than the arrow b), and the temperature difference Δt between inside and outside becomes about 9 ° C. As the temperature of the slit 7 rises, the sensor output increases, the temperature difference Δt inside and outside the slit 7 is about 9 ° C., and the sensor output shows a constant value of about 540N.
That is, when the temperature difference Δt between the radially inner wall 8 and the inner wall 9 of the slit 7 reaches a certain value (about 9 ° C.), the output value of the load sensor 19 generated by the temperature difference Δt ( About 360 N) is obtained.

  The correction data can be obtained by such measurement. As shown in FIG. 5, the correction data has a roughly proportional relationship between the temperature difference Δt and the output value of the load sensor 19 due to the temperature difference Δt. Furthermore, even if the load applied to the bearing device changes, the proportional relationship is maintained without changing. That is, as shown by the two-dot chain line in FIG. 5, when the load applied to the bearing device is increased, the temperature difference Δt increases, but when the applied load is smaller (in the case of a solid line, the case of a one-dot chain line). It will be located on the same straight line. In FIG. 5, the lines are shown slightly shifted for easy explanation. Further, the proportionality constant can be changed depending on whether the temperature difference Δt increases (d (Δt) / dt> 0) or decreases (d (Δt) / dt <0).

  In this way, by storing such correction data in the memory unit of the correction calculation unit 22 in advance, the temperature sensor 20 detects the temperature difference Δt between the inner walls 8 and 9 of the slit 7 in each slit 7. As a result, the sensor output generated by the correction calculation unit 22 due to the temperature difference Δt can be easily obtained based on the correction data. Then, by subtracting the sensor output caused by the temperature difference Δt obtained from the correction data from the output of the load sensor 19 in the slit 7, the sensor output due to the actually acting load excluding the temperature effect is obtained. It can be detected. This correction calculation is performed by the load sensor 19 and the temperature sensor 20 in each of the slits 7 before and after the upper and lower sides.

A specific installation position of each load sensor 19 will be further described. In the fixed flange portion 17, an upper slit 7a is formed at an upper portion on a vertical line passing through the axis C, and an upper load sensor 19a is provided in the upper slit 7a, and the axial measurement position of the load sensor 19a is double-rowed. The intermediate positions of the rolling elements 3a and 3b. Further, in the fixed flange portion 17, a lower slit 7b is formed in the lower portion on the vertical line, and a lower load sensor 19b is provided in the lower slit 7b, and the rolling elements 3a, The intermediate position 3b is set.
Further, a front slit 7c is formed in the front portion on the horizontal line passing through the axis C in the fixed flange portion 17, and a front load sensor 19c is provided in the front slit 7c, and the measurement position in the axial direction is It is set as an intermediate position between the double row rolling elements 3a and 3b. In addition, a rear slit 7d is formed in the rear portion of the fixed flange portion 17 on the horizontal line, and a rear load sensor 19d is provided in the rear slit 7d, and the rolling elements 3a, The intermediate position 3b is provided. It is most preferable that the “measurement position in the axial direction of the load sensor 19 is an intermediate position between the double-row rolling elements 3a and 3b”, which is most exactly the intermediate position between the double-row rolling elements 3a and 3b. This includes the case where the center position is shifted in the axial direction by a small dimension. Furthermore, it is preferable that the temperature measuring position in the axial direction of the temperature sensor 20 in each slit 7 is an intermediate position between the double-row rolling elements 3a and 3b.

  The fixed flange portion 17 is provided such that the axial position of the outer ring 2 is an intermediate position between the two rows of rolling elements 3 a and 3 b, and the load sensor 19 and the temperature are located at the center position in the thickness direction of the fixed flange portion 17. The center (measurement position) of the measurement unit of the sensor 20 is provided. According to this configuration, the load and temperature transmitted through the double row rolling elements 3a and 3b can be applied to both the load sensor 19 and the temperature sensor 20 equally from both sides. Therefore, the load sensor 19 can cancel the load component other than the direction intended for detection, and the detection accuracy can be improved.

Then, the upper load sensor 19a and the lower load sensor 19b measure the load from the vertical displacement in the respective slits 7a, 7b, and obtain the vertical load acting on the outer ring 2 by the correction calculation unit 22. Can do. Further, the front load sensor 19c and the rear load sensor 19d measure the load from the displacement in the horizontal front-rear direction in the respective slits 7c, 7d, and obtain the load in the horizontal front-rear direction acting on the outer ring 2 by the correction calculation unit 22. be able to.
Since the axial load acting on the wheel acts as a moment centering on the horizontal line in the front-rear direction on the rolling bearing device, the axial load can be obtained by the upper load sensor 19a and the lower load sensor 19b.

  Further, as shown in FIG. 2, the fixing flange portion 17 is formed with a bolt hole 24 for connection with the mounting member 18 on the vehicle body side. The slit 7 is preferably arranged on the radially inner side of the bolt hole 24 (center side of the pitch circle of the bolt hole 24). Thereby, the load which acts on the outer ring | wheel 2 can be calculated | required correctly. That is, there is a risk that deformation on the radially outer side of the pitch circle of the bolt hole 24 may be restrained by the mounting member 18 on the vehicle body side, and the detection accuracy may be reduced in the load sensor 19 provided in the slit 7. is there.

  In addition, the bearing device of the present invention is not limited to the illustrated form, and may be another form within the scope of the present invention. That is, in the above-described embodiment, the vehicle body side track member is the outer ring 2 and the wheel side track members are the inner shaft 1 and the inner ring member 14. The bearing device may be a shaft side and the wheel side race member may be the outer ring side. In this case, the sensor device 6 is provided on the inner shaft side.

It is sectional drawing which shows one Embodiment of the rolling bearing device for wheels of this invention. It is the figure which looked at the bearing apparatus of FIG. 1 from the axial direction inner side. It is a block diagram explaining a correction | amendment calculating part. It is a graph explaining the relationship between the temperature difference in a slit, and a sensor output. It is a graph explaining the data for correction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner shaft 2 Outer ring 3a Rolling body 3b Rolling body 5 Wheel side member 6 Sensor apparatus 7 Slit 8 Inner wall of radial outer side 9 Inner wall of radial inner side 17 Fixed flange part 18 Mounting member 19 Load sensor 20 Temperature sensor 22 Correction calculation part Δt Temperature difference

Claims (4)

  A vehicle body side track member fixed to the vehicle body side, a wheel side track member to which a wheel is attached, a double row rolling element interposed between these track members so as to freely roll, and a load on the vehicle body side track member A rolling bearing device for a wheel comprising a sensor device for determining a load that is applied, wherein the sensor device applies a load between a pair of inner walls facing the radial direction formed on the vehicle body side raceway member. A load sensor for measuring, and a temperature sensor for measuring a temperature difference between the inner walls in order to correct an output of the load sensor including an output generated by a temperature difference between the inner walls. Rolling bearing device for wheels.   2. The wheel rolling bearing device according to claim 1, wherein the sensor device is connected to a correction calculation unit that corrects an output of the load sensor using a measurement result of the temperature sensor. 3.   The wheel rolling bearing device according to claim 2, wherein the correction calculation unit has correction data obtained in advance for a relationship between a temperature difference between the inner walls and an output generated in the load sensor based on the temperature difference. .   A fixing flange portion for fixing the vehicle body side track member to a vehicle body side mounting member extends radially outwardly and is integrally formed with the vehicle body side track member, and the pair of inner walls are the fixing flanges Formed in the upper part, the lower part, the horizontal front part, and the horizontal rear part, respectively, and the axial measurement position of each load sensor on each of the pair of inner walls is the axial intermediate position of the rolling elements in a double row. The rolling bearing device for wheels according to any one of claims 1 to 3.

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