JP2008045903A - Bearing for vehicular wheel provided with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a vehicular bearing provided with a sensor which is capable of mounting on the vehicle, and capable of sensitively detecting the load on the wheel at a low cost at the mass production. <P>SOLUTION: If the fixing member is the external member 1, the sensor unit 21 is fixed on the external member 1. The sensor unit 21 is composed of sensor fixing member 22 and at least ≥1 strain sensors 23 fixed thereon. The sensor fixing member 22 comprises two contact fixing part 22a and 22b to the external member 1, between the contact fixing parts the first contact fixing part 22a is provided in vicinity of any fixing hole 14 on the side of flange 1a provided on the external member 1, and the second contact fixing part 22b is fixed on the external surface of the external member 1. <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, based on the detection result, the suspension is controlled in advance, so that the attitude control 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 is such that 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 demand, 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).
Special table 2003-530565 gazette

  The outer ring of the wheel bearing is a part that has a rolling surface and requires strength, and is a bearing part that is produced through complicated processes such as plastic working, turning, heat treatment, and grinding. When a strain gauge is attached to the outer ring as in Patent Document 1, there is a problem that productivity is poor and the cost for mass production is high. In addition, it is difficult to detect the distortion of the outer ring with high sensitivity, and when the detection result is used for attitude control during vehicle travel, the accuracy of control becomes a problem.

  An object of the present invention is to provide a sensor-equipped wheel bearing in which a load detection sensor can be compactly installed in a vehicle, the load applied to the wheel can be detected with high sensitivity, and the cost during mass production is low.

  The sensor-equipped wheel bearing according to the present invention includes an outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface of the outer member, A double row rolling element interposed between both rolling surfaces, and a sealing device that seals an end between the outer member and the inner member, and rotatably supports the wheel with respect to the vehicle body. A wheel having three vehicle body mounting holes for mounting on a knuckle constituting a suspension device of a vehicle body on a side surface of a flange provided on a fixed side member of the outer member and the inner member. In a bearing for a vehicle, a sensor unit comprising a sensor mounting member and at least one strain sensor mounted on the sensor mounting member is mounted on the fixed side member, and the sensor mounting member contacts the fixed side member at two locations. A fixing portion, and a contact fixing portion; The first contact fixing portion is fixed in the vicinity of any one of the vehicle body mounting holes on the side surface of the flange, and the second contact fixing portion is fixed to the peripheral surface of the fixing side member. It is characterized by that.

When a load is applied to the rotation side member as the vehicle travels, the fixed side member is deformed via the rolling elements, and the deformation causes distortion of the sensor unit. The strain sensor provided in the sensor unit detects the strain of the sensor unit. If the relationship between strain and load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected from the output of the strain sensor. Moreover, this detected load can be used for vehicle control of an automobile.
Since the wheel bearing has a configuration in which the sensor mounting unit and the sensor unit including the strain sensor mounted on the sensor mounting member are mounted on the fixed side member, the load detection sensor can be compactly installed on the vehicle. Since the sensor mounting member is a simple part that can be mounted on the fixed side member, by attaching a strain sensor to the sensor mounting member, the sensor mounting member can be excellent in mass productivity, and the cost can be reduced.
The sensor mounting member has two contact fixing portions with respect to the fixed side member, and the first contact fixing portion of the contact fixing portions is fixed to a side surface of a flange provided on the fixed side member. And the second contact fixing part is fixed to the peripheral surface of the fixed side member, and the radial positions of the first and second contact fixing parts are different, and the distortion of the fixed side member is caused by the sensor mounting member. It becomes easy to appear after being transferred and enlarged. Further, the side surface of the flange to which the first contact fixing portion is fixed receives a large force from the suspension device, so that the distortion is large. In particular, in the vicinity of the vehicle body mounting hole on the side surface of the flange, the influence of the force from the suspension device is strong and distortion is likely to appear. On the other hand, the distortion of the peripheral surface of the fixed side member to which the second contact fixing portion is fixed is not as great as that of the side surface of the flange. By providing the sensor mounting member between two places having different degrees of distortion in this manner, a larger strain appears by the sensor mounting member. Since the strain thus transferred and enlarged is measured by the strain sensor, the strain of the fixed member can be detected with high sensitivity, and the load measurement accuracy is increased.

The sensor unit may be mounted at a plurality of locations on the fixed side member, with the first contact fixing portions being positioned in the vicinity of the different vehicle body mounting holes.
At the contact point between the wheel attached to the rotating side member of the wheel bearing device and the road surface, loads in the three axial directions of the vertical direction, the horizontal direction, and the front-rear direction are applied. This load acts on the fixed side member via the rotating side member and causes distortion in the fixed side member. However, depending on the circumferential position of the vehicle body mounting hole provided in the flange of the fixed side member, the load in the three axial directions The effects of are different. Therefore, when a plurality of sensor units are mounted by positioning the first contact fixing portions in the vicinity of different vehicle body mounting holes, the relationship between the load and strain in the three axial directions differs depending on each sensor unit. The load can be obtained from the relationship between the tendency load and the strain, and the load can be detected with high accuracy.
In the case where the flange has three vehicle body mounting holes, for example, one wheel mounting hole is disposed at the upper part, and the other two wheel mounting holes are disposed at two diagonally downward front and rear positions. For this reason, the relationship between the load and strain in the three axial directions differs greatly depending on the position of each wheel mounting hole, and it becomes possible to detect the load with higher accuracy.

  The fixed member can be an outer member. In that case, the sensor unit is attached to the outer peripheral surface of the outer member.

It is preferable to provide an acting force estimating means for estimating an external force acting on the wheel bearing or an acting force between the tire and the road surface by the output of the strain sensor.
By using the external force acting on the wheel bearing obtained by the acting force estimation means or the acting force between the tire and the road surface for vehicle control of the automobile, fine vehicle control is possible.

It is preferable that the sensor unit is not plastically deformed even when a maximum force assumed as an external force acting on the stationary member or an acting force acting between the tire and the road surface is applied. The above assumed maximum force is the maximum force assumed in traveling that does not lead to vehicle failure.
When plastic deformation occurs in the sensor unit, the deformation of the fixed side member is not accurately transmitted to the sensor mounting member of the sensor unit, which affects the measurement of strain. This can be avoided by not plastically deforming the sensor unit.

The sensor mounting member may be a press-processed product.
If the sensor mounting member is manufactured by press working, the processing is easy and the cost can be reduced.

The sensor mounting member may be a sintered metal by metal powder injection molding.
When the sensor mounting member is manufactured by metal powder injection molding, a sensor mounting member with good dimensional accuracy can be obtained.

The sensor mounting member and the fixed side member can be fixed using either a bolt or an adhesive, or a combination of both, or welding.
When the sensor attachment member and the fixed side member are fixed by any one of the above methods, the sensor attachment member can be firmly fixed to the fixed side member. Therefore, the sensor mounting member is not displaced with respect to the fixed side member, and the deformation of the fixed side member can be accurately transmitted to the sensor mounting member.

A temperature sensor may be provided on the sensor mounting member.
Since the temperature of the wheel bearing changes during use, the temperature change affects the strain of the sensor mounting member or the operation of the strain sensor. It also has the same effect on changes in ambient environmental temperature. By correcting the temperature characteristics of the strain sensor based on the output of the temperature sensor, it is possible to detect a load with high accuracy.

The sensor mounting member may be provided with at least one of an acceleration sensor and a vibration sensor.
When various sensors such as an acceleration sensor and a vibration sensor are mounted on the sensor mounting member in addition to the strain sensor, the load and the state of the wheel bearing can be measured at one place, and wiring and the like can be simplified. it can.

In the strain sensor, an insulating layer may be formed on the surface of the sensor mounting member by printing and baking, and an electrode and a strain measurement resistor may be formed on the insulating layer by printing and baking.
When the strain sensor is formed as described above, there is no decrease in adhesive strength due to secular change as in the case where the strain sensor is fixed to the sensor mounting member by adhesion, and thus the reliability of the sensor unit can be improved. Moreover, since processing is easy, cost reduction can be achieved.

A sensor signal processing circuit unit having a sensor signal processing circuit for processing the output signal of the strain sensor may be provided in the vicinity of the sensor unit.
Providing a sensor signal processing circuit unit in the vicinity of the sensor unit can simplify the wiring work from the sensor unit to the sensor signal processing circuit unit. Further, the sensor signal processing circuit unit can be installed more compactly than when the sensor signal processing circuit unit is provided in a place other than the wheel bearing.

  The sensor-equipped wheel bearing according to the present invention includes an outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface of the outer member, A double row rolling element interposed between both rolling surfaces, and a sealing device that seals an end between the outer member and the inner member, and rotatably supports the wheel with respect to the vehicle body. A wheel having three vehicle body mounting holes for mounting on a knuckle constituting a suspension device of a vehicle body on a side surface of a flange provided on a fixed side member of the outer member and the inner member. In a bearing for a vehicle, a sensor unit comprising a sensor mounting member and at least one strain sensor mounted on the sensor mounting member is mounted on the fixed side member, and the sensor mounting member contacts the fixed side member at two locations. A fixing portion, and a contact fixing portion; The first contact fixing portion is fixed in the vicinity of any one of the vehicle body mounting holes on the side surface of the flange, and the second contact fixing portion is fixed to the peripheral surface of the fixing side member. Therefore, a load detection sensor can be installed in the vehicle in a compact manner, and the load applied to the wheels can be detected with high sensitivity. Since the sensor mounting member is a simple part that can be mounted on the fixed side member, by attaching a strain sensor to the sensor mounting member, the sensor mounting member can be excellent in mass productivity, and the cost can be reduced.

  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.

  This sensor-equipped wheel bearing includes an outer member 1 having a double row rolling surface 3 formed on the inner periphery, an inner member 2 having a rolling surface 4 opposed to each of the rolling surfaces 3, and these It is comprised by the double row rolling element 5 interposed between the rolling surfaces 3 and 4 of the outer member 1 and the inner member 2. This wheel bearing is a double-row angular ball bearing type, and the rolling elements 5 are made of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 are arc-shaped in cross section, and each rolling surface 3 and 4 is formed so that the contact angle is outward. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by sealing devices 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a flange 1a attached to a knuckle (not shown) in the suspension device of the vehicle body on the outer periphery, and the whole is an integral part. The flange 1a is provided with vehicle body mounting holes 14 at three locations. As shown in FIG. 2, in this embodiment, the vehicle body mounting holes 14 are arranged at equal intervals in the circumferential direction, one of which is directly above the central axis O of the bearing.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 15 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a brake component (not shown) protrudes toward the outboard side.

  A sensor unit 21 shown in FIG. 3 is provided on the outer peripheral portion of the outer member 1. The sensor unit 21 is obtained by attaching a strain sensor 23 for measuring the strain of the sensor attachment member 22 to the sensor attachment member 22. The sensor mounting member 22 includes a first contact fixing portion 22a that is fixed in contact with the surface on the outboard side of the flange 1a, and a second contact fixing portion 22b that is fixed in contact with the outer peripheral surface of the outer member 1. Have. The sensor mounting member 22 includes a radial portion 22c along the radial direction including the first contact fixing portion 22a and an axial portion 22d along the axial direction including the second contact fixing portion 22b. It is configured in an L shape. The radial portion 22c is thinned so as to be less rigid than the axial portion 22d. The strain sensor 23 is attached to the radial portion 22c having low rigidity.

  As shown in FIGS. 1 and 2, the sensor unit 21 is attached to the upper outer periphery of the outer member 1 by the first and second contact fixing portions 22 a and 22 b of the sensor attachment member 22. The fixing portion of the first contact fixing portion 22a is set in the vicinity of the vehicle body mounting hole 14 positioned directly above the central axis O on the outboard side surface of the flange 1a. The positions directly above and below the entire circumference of the outer member 1 are locations where the outer member 1 is most greatly deformed in the radial direction by a load acting on the outer member 1. Moreover, the fixing location of the 2nd contact fixing | fixed part 22b is taken as the outer peripheral surface of the outer member 1 of the 1st contact fixing | fixed part 22a and the circumferential direction same phase. Thus, by making the fixing location of the 1st and 2nd contact fixing | fixed part 22a, 22b into the circumferential direction same phase, while shortening the length of the sensor attachment member 22, the diameter between both contact fixing | fixed part 22a, 22b The direction distance can be increased. In the case of this embodiment, the strain sensor 23 is fixed to the sensor mounting member 22 using an adhesive.

  The sensor mounting member 22 has a shape or material that does not cause plastic deformation by being fixed to the outer member 1. Further, the sensor mounting member 22 needs to have a shape that does not cause plastic deformation even when the maximum load expected for the wheel bearing is applied. The above assumed maximum force is the maximum force assumed in traveling that does not lead to vehicle failure. This is because when the sensor mounting member 22 is plastically deformed, the deformation of the outer member 1 is not accurately transmitted to the sensor mounting member 22 and affects the measurement of strain.

The sensor mounting member 22 of the sensor unit 21 can be manufactured by, for example, pressing. If the sensor mounting member 22 is a pressed product, the cost can be reduced.
The sensor mounting member 22 may be a sintered metal product by metal powder injection molding. Metal powder injection molding is one of the molding techniques for metals, intermetallic compounds, etc., a step of kneading metal powder with a binder, a step of injection molding using this kneaded product, a step of degreasing the molded body, Including a step of sintering the compact. According to this metal powder injection molding, a sintered body having a higher sintering density than that of general powder metallurgy can be obtained, and sintered metal products can be manufactured with high dimensional accuracy, and mechanical strength is also high. There are advantages.

  Various strain sensors 23 can be used. For example, when the strain sensor 23 is composed of a metal foil strain gauge, considering the durability of the metal foil strain gauge, the sensor mounting member 22 can be used even when the expected maximum load is applied to the wheel bearing. It is preferable that the strain amount of the portion where the strain sensor 23 is attached is 1500 microstrain or less. For the same reason, when the strain sensor 23 is composed of a semiconductor strain gauge, the amount of strain is preferably 1000 microstrain or less. In addition, when the strain sensor 23 is formed of a thick film type sensor, the strain amount is preferably 1500 microstrain or less.

  As shown in FIG. 1, acting force estimating means 31 and abnormality determining means 32 are provided as means for processing the output of the strain sensor 23. These means 31 and 32 may be provided in an electronic circuit device (not shown) on a circuit board or the like attached to the outer member 1 of the wheel bearing, or may be an electric control unit of an automobile. (ECU) may be provided.

  The operation of the sensor-equipped wheel bearing with the above configuration will be described. When a load is applied to the hub wheel 9, the outer member 1 is deformed via the rolling elements 5, and the deformation is transmitted to the sensor mounting member 22 attached to the outer member 1, and the sensor mounting member 22 is deformed. . The strain of the sensor mounting member 22 is measured by the strain sensor 23. At this time, the radial portion 22 c of the sensor mounting member 22 is deformed according to the deformation of the flange 1 a of the outer member 1. In the case of this embodiment, the radial portion 22c is lower in rigidity than the outer member 1, and the sensor mounting member 22 is an L-shape configured by a radial portion 22c having low rigidity and an axial portion 22d having high rigidity. Therefore, distortion concentrates in the vicinity of the corner portion 22e on the radial direction portion 22c side between the radial direction portion 22c and the axial direction portion 22d, and appears as distortion larger than that of the outer member 1. That is, the distortion generated between the radial part 22c and the axial part 22d is a distortion obtained by transferring and expanding the distortion of the R portion 1b at the proximal end of the flange 1a. Further, since the radial positions of the first and second contact fixing portions 22a and 22b are different, the distortion of the outer member 1 is more likely to appear after being transferred and enlarged. Since this strain is measured by the strain sensor 23, the strain of the outer member 1 can be detected with high sensitivity, and the strain measurement accuracy is increased.

  Further, the side surface of the flange 1a to which the first contact fixing portion 22a is fixed receives a large force from the suspension device, so that the distortion is large. In particular, in the vicinity of the vehicle body mounting hole 14 in the flange 1a, the influence of the force from the suspension device is strong, and distortion is likely to appear. On the other hand, the distortion of the peripheral surface of the outer member 1 to which the second contact fixing portion 22a is fixed is not as great as that of the side surface of the flange 1a. By providing the sensor mounting member 22 between the two places having different degrees of distortion in this manner, a larger strain appears by the sensor mounting member 22, and the strain measurement accuracy is further increased. Furthermore, the position directly above the central axis O where the sensor unit 21 is provided is a location where the outer member 1 is most greatly deformed in the radial direction due to a load acting on the outer member 1. It works favorably for improvement.

  Since the strain changes depending on the direction and magnitude of the load, if the relationship between the strain and the load is obtained in advance through experiments and simulations, the external force acting on the wheel bearing or the acting force between the tire and the road surface is calculated. be able to. From the relationship between the strain and the load obtained and set in advance through experiments and simulations, the acting force estimation means 31 determines the external force acting on the wheel bearing or the distance between the tire and the road surface from the output of the strain sensor 23. Is calculated. The abnormality determining means 32 outputs an abnormality signal to the outside when it is determined that the external force acting on the wheel bearing calculated by the acting force estimating means 31 or the acting force between the tire and the road surface exceeds an allowable value. Output. This abnormal signal can be used for vehicle control of an automobile. Further, when an external force acting on the wheel bearing in real time or an acting force between the tire and the road surface is output, finer vehicle control becomes possible.

  The sensor unit 21 of this embodiment has a configuration in which only one strain sensor 23 is mounted on the sensor mounting member 22, but a configuration in which a plurality of strain sensors 23 are mounted on the sensor mounting member 22 may be employed. When a plurality of strain sensors 23 are attached to the sensor attachment member 22, it becomes possible to detect a load with higher accuracy.

  Further, in this embodiment, one of the three vehicle body mounting holes 14 provided in the outer member 1 is located directly above the central axis O of the bearing, and therefore the first of the sensor mounting member 22 The sensor unit 21 is provided so that the contact fixing portion 22a is fixed in the vicinity of the vehicle body mounting hole 14 directly above the central axis O. For example, as shown in FIG. When the one is disposed directly below the center axis O of the bearing, the sensor unit is configured such that the first contact fixing portion 22a of the sensor mounting member 22 is fixed in the vicinity of the vehicle body mounting hole 14 directly below the center axis O. 21 may be provided. That is, the first contact fixing portion 22a of the sensor mounting member 22 is directly above the entire circumference of the outer member 1 where the outer member 1 is most greatly deformed in the radial direction by a load acting on the outer member 1. The sensor unit 21 may be provided so as to be fixed as close as possible to the position or directly below the position. Thereby, it is possible to detect a load with high accuracy.

In this embodiment, the sensor unit 21 is provided only at one location of the outer member 1. However, for example, as shown in FIG. 5, the sensor unit 21 may be provided at two locations or more. If the sensor unit 21 is provided at two or more places, it becomes possible to detect a load with higher accuracy.
At the contact point between the wheel attached to the inner member 2 that is the rotation side member of the wheel bearing device and the road surface, loads in the three axial directions of the vertical direction, the horizontal direction, and the front-rear direction are applied. This load acts on the outer member 1 which is a fixed side member via the inner member 2, causing distortion in the outer member 1, but the vehicle body mounting hole 14 provided in the flange 1 a of the outer member 1. The influence of the load in the three axial directions varies depending on the circumferential position. Therefore, when the plurality of sensor units 21 are mounted by positioning the first contact fixing portions 22a in the vicinity of different vehicle body mounting holes 14, the relationship between the load and strain in the three axial directions by each sensor unit 21 is as follows. The load can be obtained from the relationship between the load and strain having a tendency different from the above, and the load can be detected with high accuracy.
When there are three vehicle body mounting holes 14 of the flange 1a, for example, one wheel mounting hole 14 is disposed at the upper part, and the other two wheel mounting holes 14 are disposed at two front and rear positions obliquely below. For this reason, the relationship between the load and strain in the three-axis directions differs greatly depending on the position of each wheel mounting hole 14, and load detection with higher accuracy is possible.

  6 and 7 show different embodiments, and in this wheel bearing, the sensor mounting member 22 of the sensor unit 21 has a linear shape. Also in this case, the sensor mounting member 22 has two contact fixing portions 22a and 22b with respect to the outer member 1, and the first contact fixing portion 22a is fixed to the vicinity of the vehicle body mounting hole 14 of the outer member 1. The second contact fixing portion 22b is fixed to the outer peripheral surface of the outer member 1 by contact. Thereby, the distortion generated in the sensor mounting member 22 is obtained by transferring and expanding the distortion of the R portion 1b at the base end of the flange 1a, so that the distortion of the outer member 1 can be detected with high sensitivity, and the distortion measurement accuracy is improved. .

  8 and 9 show a further different embodiment. In this wheel bearing, the sensor mounting member 22 is elongated in the circumferential direction, and the first contact fixing portion 22a and the second contact fixing portion 22b provided at both ends thereof are different from the circumferential direction of the outer member 1. It is fixed at the position of the phase. Also in this case, the first contact fixing portion 22a of the sensor mounting member 22 is fixed in the vicinity of the vehicle body mounting hole 14 on the side surface of the flange 1a, and the second contact fixing portion 22b is fixed to the outer peripheral surface of the outer member 1. . In the vicinity of the second contact fixing portion 22b of the sensor mounting member 22, a notch portion 22f that significantly lowers rigidity compared to other portions is formed, and the strain sensor 23 is provided at a location where the notch portion 22f is present. Installed. If the notch 22 f is formed in the sensor mounting member 22, the distortion concentrates on this part and appears as a larger distortion than the outer member 1. Since the distortion that appears greatly is measured by the distortion sensor 23, the distortion of the outer member 1 can be detected with high sensitivity, and the distortion measurement accuracy is improved.

  10 and 11 show a further different embodiment. In this wheel bearing, the sensor mounting member 22 and the outer member 1 are fixed using bolts. As shown in FIG. 11, the sensor mounting member 22 has the same overall shape as the sensor mounting member 22 shown in FIG. 3, and an axial bolt insertion hole 40 is formed in the first contact fixing portion 22a. A radial bolt insertion hole 41 is formed in the second contact fixing portion 22b. The outer member 1 is formed with bolt screw holes 42 and 43 each having a female screw on the inner peripheral surface at positions corresponding to the bolt insertion holes 40 and 41. As shown in FIG. 10, the sensor unit 21 inserts the bolt 44 from the outer peripheral side into the bolt insertion holes 40 and 41 of the sensor mounting member 22 (more precisely, the bolt 44 is inserted from the outboard side with respect to the bolt insertion hole 40). The external thread 1 is fixed to the outer member 1 by screwing the male screw portion 44a of the bolt 44 into the bolt screw holes 42, 43.

For fixing the sensor mounting member 22 and the outer member 1, either an adhesive or a bolt may be used. Moreover, you may use both together. Furthermore, you may fix the sensor attachment member 22 and the outward member 1 by welding, without using an adhesive agent and a volt | bolt.
Regardless of which of these fixing structures is employed, the sensor mounting member 22 and the outer member 1 can be firmly fixed. Therefore, the sensor mounting member 22 is not displaced with respect to the outer member 1, and the deformation of the outer member 1 can be accurately transmitted to the sensor mounting member 22.

  FIG. 12 shows a different embodiment of the sensor unit. The sensor unit 21 is provided with a temperature sensor 24 in addition to the strain sensor 23. The shape of the sensor attachment member 22 is the same as that shown in FIG. 3, and the strain sensor 23 and the temperature sensor 24 are attached to the radial portion 22 c of the sensor attachment member 22. As the temperature sensor 24, for example, a platinum resistance thermometer, a thermocouple, or a thermistor can be used. Furthermore, a sensor capable of detecting a temperature other than these can also be used.

  Also in the axle bearing provided with the sensor unit 21, the strain sensor 23 detects the strain of the sensor mounting member 22, and measures the load applied to the wheel by the strain. By the way, the temperature of the wheel bearing changes during use, and the temperature change affects the strain of the sensor mounting member 22 or the operation of the strain sensor 23. Therefore, the temperature sensor 24 arranged on the sensor mounting member 22 detects the temperature of the sensor mounting member 22 and corrects the output of the strain sensor 23 based on the detected temperature, thereby removing the influence of the temperature of the strain sensor 23. be able to. Thereby, it is possible to detect the load with high accuracy.

FIG. 13 shows a further different embodiment of the sensor unit. The sensor unit 21 is provided with various sensors 25 separately from the strain sensor 23. The various sensors 25 are at least one of an acceleration sensor and a vibration sensor. The shape of the sensor mounting member 22 is the same as that shown in FIG. 3, and the strain sensor 23 and various sensors 25 are mounted on the radial portion 22 c of the sensor mounting member 22.
Thus, when the strain sensor 23 and the various sensors 25 are attached to the sensor attachment member 22, the load and the state of the wheel bearing can be measured at one place, and wiring and the like can be simplified.

  FIG. 14 shows the structure of a sensor unit in which a strain sensor is formed by a method different from that in each of the embodiments. In the sensor unit 21, an insulating layer 50 is formed on the sensor mounting member 22, and a pair of electrodes 51, 51 are formed on both sides of the surface of the insulating layer 50, and the insulation between the electrodes 51, 51 is performed. A strain measuring resistor 52 serving as a strain sensor is formed on the layer 50, and a protective film 53 is formed on the electrodes 51, 51 and the strain measuring resistor 52.

  A method for manufacturing the sensor unit 21 will be described below. First, the insulating layer 50 is formed by printing and baking an insulating material such as glass on the surface of the sensor mounting member 22 formed of a metal material such as stainless steel. Next, a conductive material is printed and baked on the surface of the insulating layer 50 to form the electrodes 51 and 51. Furthermore, a strain measurement resistor 52 is formed between the electrodes 51 and 51 by printing and baking a material to be a resistor. Further, a protective film 53 is formed to protect the electrodes 51 and 51 and the strain measuring resistor 52.

  Usually, the strain sensor is fixed to the sensor mounting member 22 by bonding. However, this fixing structure may affect the detection of the strain sensor due to a decrease in bonding strength due to aging. It is also a cause. On the other hand, as in this embodiment, the insulating layer 50 is formed on the surface of the sensor mounting member 22 by printing and baking, and the electrodes 51 and 51 and the strain measurement resistor serving as the strain sensor are formed on the insulating layer 50. If the sensor unit 21 is formed by printing and baking, the reliability can be improved and the cost can be reduced.

  Figures 15 to 17 show a further different embodiment. This wheel bearing incorporates a sensor signal processing circuit unit 60 for processing the outputs of the strain sensors provided in the sensor unit 21 and the aforementioned sensors (temperature sensor, acceleration sensor, vibration sensor). The sensor signal processing circuit unit 60 is attached to the outer peripheral surface of the outer member 1.

  The sensor signal processing circuit unit 60 has a circuit board 62 made of glass epoxy or the like in a housing 61 made of resin or the like, and the output signal of the strain sensor 23 is processed on the circuit board 62. An operational amplifier, a resistor, a microcomputer, etc., and a power supply electric / electronic component 63 for driving the strain sensor 23 are arranged. In addition, a joint portion 64 that joins the wiring of the strain sensor 23 and the circuit board 62 is provided. Further, it has a cable 65 for supplying power from the outside and outputting an output signal processed by the sensor signal processing circuit to the outside. When the sensor unit 21 is provided with each of the above-described sensors (temperature sensor, acceleration sensor, vibration sensor), the sensor signal processing circuit unit 60 includes a circuit board 62, an electric / electronic component 63, a joint corresponding to each sensor. A portion 64, a cable 65, and the like are provided (not shown).

  In general, a sensor signal processing circuit unit for processing the output of each sensor provided in a wheel bearing is provided in an electric control unit (ECU) of an automobile. As in this embodiment, a sensor in a wheel bearing is provided. By providing the sensor signal processing circuit unit 60 in the vicinity of the unit 21, labor for wiring from the sensor unit 21 to the sensor signal processing circuit unit 60 can be simplified, and the sensor signal processing circuit unit 60 is provided at a place other than the wheel bearing. The sensor signal processing circuit unit 60 can be installed more compactly than the case of providing the sensor.

In each of the above embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. The sensor unit 21 is provided on the peripheral surface that is the inner periphery of the inner member.
In each of the above embodiments, the case where the present invention is applied to a third generation type wheel bearing has been described. However, the present invention is for a first or second generation type wheel in which the bearing portion and the hub are independent parts. The present invention can also be applied to a bearing or a fourth-generation type wheel bearing in which a part of the inner member is composed of an outer ring of a constant velocity joint. Further, this sensor-equipped wheel bearing can be applied to a wheel bearing for a driven wheel, and can also be applied to a tapered roller type wheel bearing of each generation type.

It is a figure showing combining the sectional view of the wheel bearing with a sensor concerning the embodiment of this invention, and the block diagram of the conceptual composition of the detection system. It is a front view which shows the outward member and sensor unit of the wheel bearing with a sensor. (A) is a plan view of the sensor unit, and (B) is a side view thereof. It is a front view which shows the outward member and sensor unit of a different wheel bearing with a sensor. Furthermore, it is a front view which shows the outward member and sensor unit of a different bearing for wheels with a sensor. It is sectional drawing of the bearing for wheels with a sensor concerning different embodiment of this invention. (A) is a top view of the sensor unit of the wheel bearing with a sensor, (B) is the side view. It is sectional drawing of the bearing for wheels with a sensor concerning further different embodiment of this invention. It is a front view which shows the outward member and sensor unit of the wheel bearing with a sensor. It is sectional drawing of the bearing for wheels with a sensor concerning further different embodiment of this invention. (A) is a top view of the sensor unit of the wheel bearing with a sensor, (B) is the XIB-XIB sectional drawing. (A) is a side view of a different sensor unit, and (B) is a XIIB arrow view. (A) is a side view of a further different sensor unit, and (B) is a view taken in the direction of the arrow XIIIB. Furthermore, it is a figure which shows the cross-section of a different sensor unit. It is sectional drawing of the bearing for wheels with a sensor concerning further different embodiment of this invention. It is a front view which shows the outward member and sensor unit of the wheel bearing with a sensor. It is a side view of a sensor signal processing circuit unit.

Explanation of symbols

1 ... Outer member (fixed side member)
1a ... Flange 2 ... Inward member (rotation side member)
3, 4 ... rolling surface 5 ... rolling elements 7, 8 ... sealing device 14 ... vehicle body mounting hole 21 ... sensor unit 22 ... sensor mounting member 22a ... first contact fixing portion 22b ... second contact fixing portion 23 ... distortion Sensor 24 ... Temperature sensor 25 ... Various sensors 31 ... Action force estimation means 32 ... Abnormality determination means 40 and 41 ... Bolt insertion holes 42 and 43 ... Bolt screw holes 44 ... Bolts 50 ... Insulating layers 51 and 52 ... Electrodes 53 ... Strain Measuring resistor 54 ... Protective film 60 ... Sensor signal processing circuit unit 61 ... Housing 62 ... Circuit board 63 ... Electrical / electronic component 64 ... Junction 65 ... Cable

Claims (12)

An outer member in which a double row rolling surface is formed on the inner periphery, an inner member having a rolling surface opposite to the rolling surface of the outer member, and a double row interposed between both rolling surfaces A rolling element, and a sealing device that seals an end between the outer member and the inner member, and supports a wheel rotatably with respect to a vehicle body. In the wheel bearing provided with three vehicle body mounting holes for mounting on the knuckle constituting the suspension device of the vehicle body on the side surface of the flange provided on the fixed side member of the side members,
A sensor unit comprising a sensor mounting member and at least one strain sensor mounted on the sensor mounting member is mounted on the fixed side member, and the sensor mounting member has two contact fixing portions with respect to the fixed side member. Of the contact fixing portions, the first contact fixing portion is fixed in the vicinity of any of the vehicle body mounting holes on the side surface of the flange, and the second contact fixing portion is a periphery of the fixed side member. A bearing for a wheel with a sensor, which is fixed to a surface.   The sensor-equipped wheel bearing according to claim 1, wherein the sensor unit is mounted at a plurality of locations on the fixed-side member, with the first contact fixing portions being positioned in the vicinity of the different vehicle body mounting holes.   The sensor-equipped wheel bearing according to claim 1 or 2, wherein the stationary member is an outer member.   4. The sensor-equipped wheel bearing according to any one of claims 1 to 3, wherein an estimation means for estimating an external force acting on the wheel bearing or an acting force between the tire and the road surface is provided based on the output of the strain sensor. .   In any one of claims 1 to 4, even in a state where the maximum force assumed as an external force acting on the stationary member or an acting force acting between the tire and the road surface is applied. A sensor-equipped wheel bearing wherein the sensor unit is not plastically deformed.   The sensor-equipped wheel bearing according to any one of claims 1 to 5, wherein the sensor mounting member is a press-processed product.   6. The wheel bearing with sensor according to claim 1, wherein the sensor mounting member is a sintered metal by metal powder injection molding.   In any one of claims 1 to 7, whether the sensor mounting member and the fixed side member are fixed using either a bolt or an adhesive, or a combination of both, Or a bearing for a wheel with a sensor using welding.   9. The wheel bearing with sensor according to claim 1, wherein a temperature sensor is provided on the sensor mounting member.   The sensor-equipped wheel bearing according to claim 1, wherein at least one of an acceleration sensor and a vibration sensor is provided on the sensor mounting member.   11. The strain sensor according to claim 1, wherein the strain sensor is formed by printing and baking an insulating layer on a surface of the sensor mounting member, and an electrode and a strain measurement resistor are formed on the insulating layer. Sensor-equipped wheel bearing formed by printing and firing.   The bearing for sensor wheel according to any one of claims 1 to 11, wherein a sensor signal processing circuit unit having a sensor signal processing circuit for processing an output signal of the strain sensor is provided in the vicinity of the sensor unit.

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