JP4879529B2 - Wheel bearing with sensor - Google Patents

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 and the like are controlled in advance, thereby controlling the posture 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

An outer ring of a wheel bearing has a rolling surface and is a component that requires strength, and is a bearing component that is produced through complicated processes such as plastic working, turning, heat treatment, and grinding. Therefore, 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.
Further, the output signal of a load detection sensor such as a strain gauge is transmitted to, for example, a sensor signal processing circuit provided in an electric control unit of an automobile, and the external force acting on the wheel bearing and the acting force of the tire and the road surface are measured. Although used for calculation and various vehicle controls, conventionally, there is a problem that wiring for connecting a sensor for detecting a load and a sensor signal processing circuit is complicated and the wiring work is not easy.
Wheel bearings are components of automobiles used in various harsh situations. For this reason, it is necessary to accurately grasp the state of the axle bearing in order to properly perform various controls of the automobile, axle life, determination of necessity of maintenance, and the like. The matters that should be known about the state of the axle bearing include, for example, how much the value of the rotational acceleration is, how much it vibrates, and whether water has entered the bearing space. If the acceleration is known, the vehicle can be controlled more appropriately. Vibration is one of the most important factors in determining bearing life. Water intrusion greatly affects grease degradation. It would be preferable if means for detecting the state of these axle bearings could be provided at low cost without complicating the detection system.

  The object of the present invention is to be able to install various sensors for detecting the state of a load detection sensor and wheel bearings in a compact vehicle, and the wiring connecting these sensors to the sensor signal processing circuit is simple. The object is to provide a wheel bearing that is inexpensive.

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 sensor-equipped wheel bearing comprising a double-row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, comprising a sensor mounting member and a strain sensor mounted on the sensor mounting member. A sensor unit is attached to a fixed side member of the outer member and the inner member, the sensor mounting member has at least two contact fixing portions with respect to the fixed side member , is a substantially arc shape extending in a circumferential direction along the circumferential surface of the stationary member, the both end portions of the substantially arc-shaped sensor mounting member, the contact fixing portions that projects on the stationary member side is formed respectively, next to fit the contact fixing At least one notch between parts The strain sensor is attached to the notch, and a sensor signal processing circuit unit for processing an output signal of the strain sensor is provided in the vicinity of the sensor unit in the fixed side member. The circuit unit is provided with at least one of an acceleration sensor, a vibration sensor, and a moisture detection sensor. For example, when the outer member is a stationary member and the inner member is a rotating member, the sensor unit is attached to the outer member.

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 the strain and the load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected by processing the output signal of the strain sensor with the sensor signal processing circuit unit. That is, the external force acting on the wheel bearing, the acting force between the tire and the road surface, or the preload amount of the wheel bearing can be estimated from the output of the strain sensor. Further, the detected load or the like can be used for vehicle control of the automobile.
The sensor mounting member of the sensor unit has at least two contact fixing portions with respect to the fixed side member, and has at least one notch portion between adjacent contact fixing portions. Since the sensor is arranged, the distortion location of the strain sensor on the sensor mounting member causes a larger distortion than the fixed side member due to a decrease in rigidity, and the distortion of the fixed side member can be detected with high accuracy.

  In addition, the state of the axle bearing is detected by at least one of various sensors provided in the sensor signal processing circuit unit, that is, an acceleration sensor, a vibration sensor, and a moisture detection sensor. Output signals from various sensors are processed by a sensor signal processing circuit unit as necessary. And it uses for the vehicle control of a motor vehicle with the load etc. which were detected by the distortion sensor.

The sensor equipped wheel support bearing assembly is mounted a strain sensor to a sensor attachment member attached to the stationary member, also because attaching the various sensors in the sensor signal processing circuit unit attached to the stationary member, the strain sensors and various compactly in the vehicle Sensors can be installed. Since both the sensor mounting member and the sensor signal processing circuit unit are simple parts that can be mounted on the fixed side member, there are a strain sensor, various sensors (at least one of an acceleration sensor, a vibration sensor, and a moisture detection sensor). By attaching each separately, it can be made excellent in mass productivity and cost can be reduced.
Since the sensor signal processing circuit unit is provided in the vicinity of the sensor unit, the wiring connecting the strain sensor and the sensor signal processing circuit is simplified, and the wiring work of the wiring is facilitated. Since various sensors (at least one of an acceleration sensor, a vibration sensor, and a moisture detection sensor) for detecting the state of the axle bearing are attached to the sensor signal processing circuit unit, the various sensors and the sensor signal processing circuit unit are installed. Wiring is not necessary. Moreover, by providing various sensors (acceleration sensor, vibration sensor, moisture detection sensor) in the sensor signal processing circuit unit, it is possible to measure the load and the state of the wheel bearing at one place. Therefore, as compared with the case where a sensor signal processing circuit is provided in addition to the axle bearing, the entire detection system is compact and wiring can be simplified.

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 sensor-equipped wheel bearing comprising a double-row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, comprising a sensor mounting member and a strain sensor mounted on the sensor mounting member. A sensor unit is attached to a fixed member of the outer member and the inner member, and a sensor signal processing circuit unit for processing an output signal of the strain sensor is provided in the vicinity of the sensor unit in the fixed member. Since the sensor signal processing circuit unit is provided with at least one of an acceleration sensor, a vibration sensor, and a moisture detection sensor, the load sensor and various sensors are compactly installed in the vehicle. It can be installed. In addition, the sensor mounting member and the sensor signal processing circuit unit are both simple parts that can be mounted on the fixed side member, so that a strain sensor and various sensors can be individually mounted on the sensor mounting member and the sensor signal processing circuit unit. And cost reduction can be achieved.
Since the sensor signal processing circuit unit is provided in the vicinity of the sensor unit, the wiring connecting the strain sensor and the sensor signal processing circuit is simple and the wiring work is easy, and the various sensors are attached to the sensor signal processing circuit unit. Since it is attached, wiring for connecting various sensors to the sensor signal processing circuit unit is unnecessary. Moreover, by providing various sensors (acceleration sensor, vibration sensor, moisture detection sensor) in the sensor signal processing circuit unit, it is possible to measure the load and the state of the wheel bearing at one place. For this reason, compared with the case where a sensor signal processing circuit is provided in addition to the axle bearing, the entire detection system is compact and wiring can be simplified.
The sensor mounting member has at least two contact fixing portions with respect to the fixed side member, and the sensor mounting member has a substantially arc shape extending in a circumferential direction along the peripheral surface of the fixed side member. at both ends of the arcuate sensor mounting member, formed contact fixing portions that projects on the stationary member side, respectively, has a notch in at least one location between the contact fixing portions fit next to the strain sensor in this notch The sensor mounting member has at least two contact fixing portions with respect to the fixed side member, and has at least one notch portion between adjacent contact fixing portions, Since the strain sensor is attached to the notch, the strain sensor placement location of the sensor mounting member causes a strain larger than that of the fixed side member due to a decrease in its rigidity, and the distortion of the fixed side member is accurately performed. To detect Can.

A first 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.
The 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 transfer surface 3, and the outer members. 1 and a double row rolling element 5 interposed between the rolling surfaces 3 and 4 of 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 transfer surfaces 3 and 4 have an arc shape in cross section, and the rolling surfaces 3 and 4 are 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 means 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a flange 1a attached to a knuckle in a suspension device (not shown) of a 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 a plurality of locations in the circumferential direction.
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.

  Two sensor units 21 and a sensor signal processing circuit unit 25 electrically connected to these sensor units 21 are provided on the inner periphery of the outer board 1 on the outboard side end. The axial positions of the units 21, 21, and 25 are the same as each other, and the outboard side, more specifically, the outboard side rolling surface 3 and the sealing means 7 are arranged on the outboard side than the outboard side rolling surface 3. Between.

  As shown in FIGS. 2 and 3, the sensor mounting member 22 has a substantially arc shape that is elongated in the circumferential direction along the inner peripheral surface of the outer member 1, and is a contact fixing portion that protrudes to the outer peripheral side of the arc at both ends thereof. 22a and 22b are formed. In addition, a notch 22c that opens to the outer peripheral side of the arc is formed at the center of the sensor mounting member 22, and the strain sensor 23 is attached to the inner peripheral surface of the arc that is located at the back of the notch 22c. Yes. The cross-sectional shape of the sensor mounting member 22 is, for example, a rectangular shape, but can be various other shapes.

The sensor unit 21 is fixed to the outer member 1 by the contact fixing portions 22 a and 22 b of the sensor mounting member 22. The contact fixing portions 22a and 22b are fixed to the outer member 1 by fixing with bolts or bonding with an adhesive. A gap is formed between the sensor mounting member 22 and the outer member 1 at locations other than the contact fixing portions 22a and 22b.
The sensor mounting member 22 is preferably a member that is not plastically deformed at the maximum expected external force acting on the wheel bearing or the acting force between the tire and the road surface when mounted on the outer member 1. As a material of the sensor mounting member 22, a metal material such as copper, brass, and aluminum can be used in addition to a steel material.

  In the case of this embodiment, the sensor units 21 are provided at two locations in the circumferential direction on the inner circumferential surface of the outer member 1. In the first sensor unit 21 (1), one contact fixing portion 22a is positioned right above the entire circumference of the outer member 1, and the other contact fixing portion 22b is positioned several tens of degrees below the directly above position. Are arranged to be. In the second sensor unit 21 (2), one contact fixing portion 22a is located directly below the entire circumference of the outer member 1, and the other contact fixing portion 22b is located several tens of degrees above the directly below position. Are arranged to be. The positions directly above and below the entire circumference of the outer member 1 are locations where the outer member 1 is most deformed in the radial direction by a load acting on the outer member 1, and is several tens of degrees below the position immediately above. A position that is several tens of degrees above the position and the position just below is a place where there is less deformation in the radial direction than the position just above and the position just below.

  As shown in FIGS. 2 and 4, the sensor signal processing circuit unit 25 has an arc-shaped housing 26 that is formed of resin or the like and extends along the inner peripheral surface of the outer member 1. A circuit board 27 manufactured by the method described above and a plurality of electrical and electronic components 28 arranged on the circuit board 27 are accommodated. The plurality of electrical and electronic components 28 are composed of operational amplifiers, resistors, microcomputers, etc. for processing the output signals of the strain sensor 23 and power supply components for driving the strain sensor 23. The circuit board 27 and the electrical and electronic components 28 constitute a sensor signal processing circuit that processes the output signal of the strain sensor 23. Then, the ends of the wiring 30 connected to the strain sensor 23 are joined to the joints 29 provided at both ends of the housing 26. In addition, a cable 31 is connected to the central portion of the housing 26 for supplying electric power from the outside to the sensor signal processing circuit and outputting the signal processed by the sensor signal processing circuit to the outside.

  Further, the sensor signal processing circuit unit 25 is integrally attached with various sensors 32 for detecting the state of the wheel bearing. The various sensors 32 are at least one of an acceleration sensor that detects acceleration of rotation, a vibration sensor that detects vibration of the outer member 1, and a moisture detection sensor that detects whether or not moisture exists in the bearing space. The

  As shown in the block diagram of FIG. 5, the sensor signal processing circuit includes an external force calculation means 40, a road surface acting force calculation means 41, a bearing preload amount calculation means 42, and an abnormality determination means 43. The function of each means will be described later.

  The inboard side sealing means 8 includes a seal 8a made of an elastic body such as rubber with a core attached to the inner peripheral surface of the outer member 1, and the seal 8a attached to the outer peripheral surface of the inner ring 10. The slinger 8b is in contact with the slinger 8b. The slinger 8b is provided with a magnetic encoder 16 for rotation detection, which is composed of a multipolar magnet having magnetic poles alternately in the circumferential direction. A magnetic sensor (not shown) is attached to the outer member 1 so as to face the magnetic encoder 16.

  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 mounted on the inner periphery of the outer member 1, and the sensor mounting member 22. Is deformed. Since the sensor unit 21 is disposed at a position closer to the outboard side than the rolling surface 3 on the outboard side, distortion of the outer member 1 appears greatly in the sensor mounting member 22. The strain of the sensor mounting member 22 is measured by the strain sensor 23. At this time, the sensor mounting member 22 is deformed in accordance with the radial deformation of the fixing portion of the sensor mounting member 22 in the outer member 1, but the sensor mounting member 22 has an arc shape compared to the outer member 1 and has a notch portion. Since 22c is provided and the rigidity of the location of this notch part 22c is falling, the distortion larger than the distortion of the outer member 1 appears in the sensor attachment member 22. FIG. For this reason, even a slight distortion of the outer member 1 can be accurately detected by the distortion sensor 23.

  Of the two contact fixing portions 22 a and 22 b of the sensor mounting member 22, one of the contact fixing portions 22 a is a portion where the outer member 1 is most greatly deformed in the radial direction due to a load acting on the outer member 1. The other contact fixing portion 22b is positioned directly above or directly below a certain circumference, and the other contact fixing portion 22b is positioned several tens of degrees below or several tens of degrees above from just above and below the radial direction. Therefore, when the contact fixing portion 22a is greatly deformed with the contact fixing portion 22b as a fulcrum, the mounting portion of the strain sensor 23 of the sensor mounting member 22 is further strained. For this reason, the strain of the outer member 1 can be detected with high sensitivity by the strain sensor 23.

  By processing the output signal of the strain sensor 23 by the sensor signal processing circuit of the sensor signal processing circuit unit 25, an external force or the like acting on the axle bearing is detected. 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. The external force calculating means 40 and the road surface acting force calculating means 41 are based on the relationship between the strain and the load obtained and set in advance through experiments and simulations as described above. The acting force between the tire and the road surface is calculated respectively.

The abnormality determining means 43 outputs an abnormality signal to the outside when it is determined that the external force acting on the wheel bearing calculated in this way or the acting force between the tire and the road surface exceeds a set allowable value. . This abnormal signal can be used for vehicle control of an automobile.
Further, when the external force calculating means 40 and the road surface acting force calculating means 41 output the external force acting on the wheel bearing in real time or the acting force between the tire and the road surface, finer vehicle control becomes possible.

  Further, a preload is applied to the wheel bearing by the inner ring 10, and the sensor mounting member 22 is also deformed by the preload. For this reason, if the relationship between strain and preload is obtained in advance through experiments and simulations, the preload state of the wheel bearing can be known. The bearing preload amount calculation means 42 outputs the bearing preload amount based on the output of the strain sensor 23 from the relationship between the strain and the preload obtained and set in advance through experiments and simulations as described above. Further, by using the preload amount output from the bearing preload amount calculating means 42, it becomes easy to adjust the preload when the wheel bearing is assembled.

  Further, the state of the wheel bearing is detected by various sensors 32. The detected state of the wheel bearing can be used for vehicle control, life determination, maintenance determination and the like of the automobile. For example, when an acceleration sensor is provided as the various sensors 32, it can be used for driving control of an automobile. When a vibration sensor is provided, the bearing life can be predicted and managed from the vibration state. In the case where a moisture detection sensor is provided, the amount of moisture that has entered the bearing space from the sealing means 7 and 8 can be detected, and the deterioration of grease due to the ingress moisture can be known.

Each of the above embodiments has been described with respect to the case where the outer member is a fixed-side member, but the present invention can also be applied to a wheel bearing in which the inner member is a fixed-side member. The attachment member is attached to the outer peripheral surface or inner peripheral surface of the inner member.
Moreover, although each said embodiment demonstrated about the case where it applied to the bearing for 3rd generation type wheels, this invention is for 1st or 2nd generation type wheels from which a bearing part and a hub become mutually independent components. A bearing or a fourth generation type wheel bearing in which a part of the inner member is constituted by an outer ring of a constant velocity joint can also be applied. Further, the 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 sectional drawing of the bearing for wheels with a sensor concerning this Embodiment. It is a front view which shows the outward member, sensor unit, and sensor signal processing circuit unit of the wheel bearing. (A) is a front view of the sensor unit, and (B) is a bottom view thereof. It is a front view of a sensor signal processing circuit unit. It is a block diagram of a sensor signal processing circuit unit.

Explanation of symbols

1 ... Outer member (fixed side member)
2 ... Inward member (rotary member)
3, 4 ... rolling surface 5 ... rolling elements 7, 8 ... sealing means 21 ... sensor unit 22 ... sensor mounting member 22a, 22b ... contact fixing part 22c ... notch 23 ... strain sensor 25 ... sensor signal processing circuit unit 32 ... Various sensors

Claims (2)

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 In the wheel bearing with sensor for supporting the wheel rotatably with respect to the vehicle body,
A sensor unit comprising a sensor mounting member and a strain sensor mounted on the sensor mounting member is mounted on a fixed side member of the outer member and the inner member, and the sensor mounting member is at least 2 with respect to the fixed side member. The sensor mounting member has a substantially arc shape extending in the circumferential direction along the peripheral surface of the fixed side member, and the both ends of the substantially arc-shaped sensor mounting member are connected to the fixed side member side. is the contact fixing segments is respectively formed with flared, has a notch in at least one location between the contact fixing portions fit next, which was fitted with the strain sensor in this notch, said sensor in said stationary member A sensor signal processing circuit unit for processing the output signal of the strain sensor is provided in the vicinity of the unit. The sensor signal processing circuit unit includes an acceleration sensor, a vibration sensor, and a sensor. Sensor with wheel bearing, characterized in that a least one of the moisture sensor.   The sensor-equipped wheel bearing according to claim 1, wherein the fixed-side member is an outer member.

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