JP2006009866A - Wheel bearing with built-in load sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with a built-in load sensor which enables the compact installation of a load sensor and the stable detection of a load applied to a wheel. <P>SOLUTION: A double-row rolling elements 3 are intervened between raceways 4, 5 where an outward member 1 and an inward member 2 are opposed to each other and both ends of both the members 1, 2 are sealed with a sealing means 7, 8. The inward member 2 includes a hub ring 2A formed with a flange 2a used for fitting the hub ring 2A. A plurality of displacement sensors 10 are positioned circumferentially which are located between the flange 2a of the hub ring 2A and the rolling elements 3 and are intended to measure a gap between the outward member 1 and the inward member 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wheel bearing having 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. In such wheel bearings, there are also proposed sensors in which sensors such as a temperature sensor and a vibration sensor are installed so that other states useful for driving a car can be detected in addition to the rotational speed (for example, Patent Documents). 1).
Japanese Patent Laid-Open No. 2003-336652

  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 to be able to control the surface. 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.

  In the wheel bearing incorporating the load sensor shown in Patent Document 1, the load is obtained by measuring the gap with the surface of the outer member by the displacement sensor fixedly supported by the vehicle body mounting flange. It is exposed to and remains a problem in durability. Further, the amount of deformation of the outer member is small, and the detection accuracy is limited.

An object of the present invention is to provide a load sensor built-in wheel bearing capable of eliminating such a problem and installing a load sensor compactly in a vehicle and stably detecting a load applied to the wheel.
Another object of the present invention is to provide a load sensor built-in wheel bearing capable of mounting the sensor reliably, having excellent reliability, easily adapting to various sizes of bearings, and reducing the cost. .

  A wheel sensor built-in wheel bearing according to the present invention includes an outer member having a double-row rolling surface on an inner peripheral surface, a hub wheel formed with a wheel mounting flange, and the outer member rolling. An inner member having a double-row rolling surface facing the surface, a double-row rolling element interposed between both rolling surfaces, and a sealing means for sealing both ends of the outer member and the inner member, In a wheel bearing for rotatably supporting a wheel with respect to a vehicle body, an outer member and an inner member are positioned between the flange of the hub wheel and a rolling element as means for detecting a load acting on the wheel bearing. One or a plurality of displacement sensors for measuring the gap with the member are arranged in the circumferential direction.

  In the wheel bearing device, the space between the flange of the hub wheel and the rolling element is a relatively easy space. In particular, when the wheel bearing device is an angular ball bearing type, the portion that becomes the outboard side end of the outer member is unnecessary from the viewpoint of structural strength because of the contact angle, and this portion may be cut off. Is possible. By placing a displacement sensor that measures the gap between the outer member and the inner member between the flange of the hub wheel with sufficient space and the rolling element, a compact load is applied to the vehicle. Sensors can be installed. A single displacement sensor is sufficient in the circumferential direction. However, since a plurality of displacement sensors are arranged here, stable load detection such as absorption of output fluctuations due to eccentricity of the hub wheel and reduction of eccentricity errors due to averaging of sensor outputs is possible. It is possible to improve the sensitivity or to detect a load having a different direction. Thus, a load sensor can be installed compactly in the vehicle, and the load applied to the wheels can be detected stably.

The displacement sensor may take an output difference between two displacement sensors provided at positions that face each other by 180 degrees.
By taking the output difference between the two displacement sensors at the positions facing each other by 180 degrees, it is possible to cancel the output fluctuation due to the eccentricity of the hub wheel and to double the sensitivity.

  The displacement sensor may be a reluctance type in which a coil is wound around a magnetic yoke. A reluctance type sensor can detect displacement with high accuracy and stability with a simple configuration.

In this invention, a plurality of protruding yokes are formed on the inner diameter side of a ring plate made of a magnetic material, coil windings are applied to each yoke, and the ring plate provided with the coil windings is fixed to an outer member. May be.
In the case of this configuration, a plurality of yokes can be protruded from the same ring plate made of a magnetic material and attached to the outer member, so that the number of parts and the number of assembly steps can be reduced.

In the present invention, coil windings wound around a plurality of protruding yokes having a mechanical angle of 90 degrees or less may be connected to form one sensor coil winding.
In this way, when the number of yokes is increased by providing yokes in the range of 90 degrees or less and the coil windings of a plurality of yokes are connected and handled as one sensor coil winding, the sensor outputs are averaged and biased. The center error can be reduced, and the fluctuation of the sensor output due to the rotational vibration of the hub wheel is suppressed.

In the present invention, one yoke circumferential width may be 90 degrees or less, and may be a circumferential width close to approximately 90 degrees within a range in which a winding can be interposed. For example, the circumferential width is 70 degrees or more.
In this configuration, by widening the circumferential angle at the tip of the yoke, the sensor output can be averaged to reduce the eccentric error, and the fluctuation of the sensor output due to the rotational vibration of the hub wheel can be suppressed.

In this invention, a displacement is obtained by providing a plurality of holes along the radial center of the non-magnetic ring member in the radial direction and applying coil windings to the convex part of the yoke made of a magnetic material having an E-shaped cross section having a convex part at the center. The sensor may be fixed to the hole of the ring member, and the convex portion of each yoke may be opposed to the inner member.
In the case of this configuration, coil windings can be wound around individual yokes, and the yoke around which the coils are wound can be assembled in the hole of the ring member. Therefore, the winding work is simplified, and the attaching work of the yoke to the outer member is simplified.

In the present invention, the displacement sensor detects the load based on the result of measuring the gap facing the outer diameter surface of the hub wheel formed between the flange surface of the hub wheel and the rolling surface. Also good.
When the weight of the wheel bearing changes or when a vertical moment load is applied to the wheel mounting flange during cornering, the contact surface between the rolling element and the rolling surface of the wheel bearing moves, and the hub wheel is centered Tilts. Thereby, the clearance gap between each yoke of a load sensor and a to-be-detected part changes. The load applied to the wheel bearing can be estimated from the measured values of the gaps that change in this way.

In the present invention, the displacement sensor may detect a load based on a result of measuring a gap between the flange side surface of the hub wheel and the outer member.
In the case of this configuration, a displacement that changes due to a moment load applied to the flange of the hub wheel is detected, and the load can be calculated from this displacement.

In this invention, when the inner member has an inner diameter hole, and the stem portion of the constant velocity joint is inserted into the inner diameter hole and the inner member and the constant velocity joint are combined, the constant velocity joint The stem portion may be shorter than the axial length of the inner diameter hole of the hub wheel.
If the stem portion of the constant velocity joint is shorter than the inner diameter hole length of the hub wheel, the rigidity of the hub wheel, a part of which becomes the detected portion of the load sensor, can be reduced within a range that does not affect the strength. Thereby, the axis of the hub wheel 2A is easily inclined, and the sensitivity of the load sensor can be improved.

  In this invention, the displacement sensor may be incorporated inside the bearing of the sealing means. If a displacement sensor is incorporated inside the sealing means, the displacement sensor will not change over time from the environment, and can withstand long-term use.

  Another load sensor built-in wheel bearing according to the present invention includes an outer member having a double row rolling surface on an inner peripheral surface, and an inner member having a double row rolling surface facing the rolling surface of the outer member. A wheel bearing comprising a side member and a double row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, and an encoder attached to an end of the inner member; A rotation sensor having a detection portion attached to the end portion of the outer member facing the encoder and a displacement sensor having a detection portion attached facing the joint that is spline-fitted to the inner member are provided. Also good. In this case, a sensor mounting member having a fitting tube portion that fits on the outer diameter surface of the outer member and a side plate portion that is in axial contact with the end surface of the outer member is provided. The side plate portion of the member may be provided with inner and outer facing plate portions facing each other, and the rotation sensor and the displacement sensor may be sandwiched between the inner and outer facing plate portions.

  In this configuration, the rotation sensor and the displacement sensor are sandwiched between the inner and outer opposing plate parts provided on the sensor mounting member, so there is no risk of the sensor coming off, and the mounting is reliable and reliable. it can. The sensor mounting member is fitted to the outer diameter surface of the outer member at the fitting tube portion, and is positioned in the axial direction by contacting the end surface of the outer member at the side plate portion. The positioning accuracy is excellent. The sensor is, for example, a sensor element embedded in a sensor holder made of resin or the like. The sensor holder is manufactured separately from the sensor mounting member and is attached to the sensor mounting member. Therefore, when mounting on bearing parts of different sizes, it can be dealt with by adjusting the sensor mounting member to the size of the bearing section. It can correspond to the part. Therefore, a sensor unit including the sensor and the sensor mounting member can be manufactured at low cost.

In the present invention, both the rotation sensor and the displacement sensor attached in a sandwiched state between the inner and outer opposing plate portions may be arranged at positions above and below in the vertical direction with respect to the bearing center and on both sides in the horizontal direction. good.
By providing displacement sensors on both the vertical and horizontal sides, it is possible to detect both the vertical load and the longitudinal load on the wheel.

In the present invention, a plurality of displacement sensors may be provided, and at least one of the plurality of displacement sensors may be resin-molded together with the rotation sensor.
By resin-molding the displacement sensor and the rotation sensor together, both the displacement sensor and the rotation sensor can be provided while avoiding an increase in the number of parts and the number of assembly steps.

  A wheel sensor built-in wheel bearing according to the present invention includes an outer member having a double-row rolling surface on an inner peripheral surface, a hub wheel formed with a wheel mounting flange, and the outer member rolling. An inner member having a double-row rolling surface facing the surface, a double-row rolling element interposed between both rolling surfaces, and a sealing means for sealing both ends of the outer member and the inner member, In a wheel bearing for rotatably supporting a wheel with respect to a vehicle body, a displacement sensor that is positioned between the flange of the hub wheel and a rolling element and measures a gap between an outer member and an inner member is arranged in a circumferential direction. Therefore, a load sensor can be installed on the vehicle in a compact manner, and the load applied to the wheels can be detected stably.

  Another load sensor built-in wheel bearing according to the present invention includes an outer member having a double row rolling surface on an inner peripheral surface, and an inner member having a double row rolling surface facing the rolling surface of the outer member. A wheel bearing comprising a side member and a double row rolling element interposed between both rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, and an encoder attached to an end of the inner member; A rotation sensor having a detection portion attached to the end of the outer member facing the encoder, and a displacement sensor having a detection portion attached facing the joint that is spline-fitted to the inner member, A sensor mounting member having a fitting tube portion that fits to the outer diameter surface of the outer member and a side plate portion that is positioned in the axial direction in contact with the end surface of the outer member is provided, and the side plate of the sensor mounting member The inner and outer pairs facing each other Since the plate part is provided and the rotation sensor and displacement sensor are sandwiched between the inner and outer opposing plate parts, both rotation and load can be measured, and there is no risk of the sensor coming off, so installation is reliable. Therefore, it can be made highly reliable.

A first embodiment of the present invention will be described with reference to FIGS. The load sensor built-in wheel bearing of this embodiment is a third generation type inner ring rotating type and is an example applied to a wheel bearing for driving wheel support. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side. In FIG. 1A, the left side is the outboard side and the right side is the inboard side.
In FIG. 1 (A), this wheel bearing 18 has an outer member 1 having a double row rolling surface 4 on the inner periphery and an inner surface having rolling surfaces 5 respectively facing the rolling surfaces 4 on the outer periphery. A side member 2 and a double row rolling element 3 interposed between the double row rolling surfaces 4 and 5 are provided. The wheel bearing 18 is a double-row angular contact ball bearing, the rolling surfaces 4 and 5 are arc-shaped in cross section, and the contact angles of the rolling surfaces 4 and 5 are back to back. Is formed. The rolling elements 3 are formed of balls and are held by the cage 6 for each row.

  The outer member 1 is a member on the fixed side, and has a vehicle body mounting flange 1a for fixing to a knuckle (not shown) on the outer periphery as shown in FIG. It is said that. The vehicle body mounting flange 1a is fastened to a knuckle installed in a vehicle body (not shown) with a plurality of bolts (not shown) in the circumferential direction. The bolt insertion hole 12 of the vehicle body mounting flange 1a is threaded. The bolt passes through a through hole provided in the knuckle, and the male screw portion at the tip is screwed into the bolt insertion hole 12. Instead of using the bolt insertion hole 12 as a screw hole, the bolt may be tightened with a nut (not shown) simply as a hole through which the bolt is inserted.

  The inner member 2 is a member on the rotation side, and a hub wheel 2A having a wheel mounting flange 2a on the outer periphery, and a separate member fitted to the outer diameter surface of the end portion on the inboard side of the hub wheel 2A. It consists of an inner ring 2B, and an outer ring 13a of a constant velocity joint 13 is connected to the hub ring 2A. Each row of rolling surfaces 5 is formed on the hub wheel 2A and the inner ring 2B. A stem portion 14 formed integrally with the outer ring 13 a of the constant velocity joint 13 is inserted into the inner diameter hole 29 of the hub wheel 2 </ b> A, and a bolt 16 is provided in the center of the stem portion 14 via a washer 15. The constant velocity joint outer ring 13a is connected to the hub wheel 2A by being screwed to 14a. The washer 15 is disposed so as to abut on a stepped surface 2e formed on the outboard side of the inner diameter hole 29 of the hub wheel 2A, and a bolt 16 inserted through the washer 15 is inserted into the screw hole 14a of the stem portion 14. By screwing, the constant velocity joint outer ring 13a is pressed and connected to the hub wheel 2A on the outboard side. The washer 15 may be fixed to the hub wheel 2A with a bolt (not shown) so that it cannot be rotated.

  A spline groove 2b is formed on the inboard side of the inner diameter hole 29 of the hub wheel 2A from the position corresponding to the wheel mounting flange 2a, and the spline groove formed on the outer peripheral surface of the stem portion 14 in the spline groove 2b. 14b is spline-fitted. The inner ring 2B is clamped and fixed in the axial direction with respect to the hub wheel 2A by a crimping portion 2Aa provided at the inboard side end of the hub wheel 2A. The open end portions on the outboard side and the inboard side of the annular space formed between the inner and outer members 2 and 1 are sealed by contact-type seals 7 and 8 which are sealing devices, respectively. Particularly, the lip portion 7a of the seal 7 on the outboard side is slidably contacted with the side surface 2c of the wheel mounting flange 2a to ensure the sealing performance. Further, an O-ring 17 is interposed between the axial engagement surface 13aa of the constant velocity joint outer ring 13a with the hub wheel 2A and the width surface of the inner ring 2B facing the axial engagement surface 13aa. This prevents moisture and foreign matter from entering the joint of the spline grooves 2b and 14b.

  The load sensor 9 is arranged in a space body sandwiched between the wheel mounting flange 2a of the wheel bearing 18 and the rolling surfaces 4 and 5 on the outboard side. The load sensor 9 includes a displacement sensor 10 that is a detection unit and a detected portion 11 that is detected by the displacement sensor 10 of the hub wheel 2A. The load sensor 9 detects that the hub wheel 2A is inclined by the load and estimates the load. It is supposed to be processed. The displacement sensor 10 includes a plurality of yokes 10a and coil windings 10b, and is fixed to the inner diameter surface of the outer member 1 by press-fitting or the like. Further, the entire circumference of the hub wheel 2A facing the tip of the yoke 10a of the displacement sensor 10 is used as the detected part 11, and the surface of the detected part 11 is ground and the like so that rotational runout is reduced. It is produced by managing the etc. The load sensor 9 is incorporated inside the bearing of the seal 7. As a result, the load sensor 9 is free from adhesion of moisture, dust, etc., and is maintained in an environmentally good state, and can withstand long-term use.

  FIG. 2 schematically shows a cross section of the load sensor 9. The displacement sensor 10 of the load sensor 9 is a reluctance type in which a coil 10b is wound around a yoke 10a, and a plurality (in this case, four of 10A to 10D) are arranged in the circumferential direction. The yokes 10a1 to 10a4 of the displacement sensors 10A to 10D are integrally formed to protrude toward the inner diameter side at four locations on the top, bottom, left and right of the ring plate 10c made of a magnetic material, and are separated from each other by 90 degrees in mechanical angle. Is in position. The coils 10b1 to 10b4 are wound around the yokes 10a1 to 10a4, respectively. The winding processing of the coils 10b1 to 10b4 is performed so that the polarities of adjacent yokes are different from each other. The coil winding 10b may be wound directly around the yoke 10a, or a resin bobbin (not shown) may be interposed.

  In a state where no load is applied to the wheel bearing 18, the tips of the yokes 10 a 1 to 10 a 4 are set so that the gaps with the detected part 11 are substantially the same. The magnetic parts constituting the ring plate 10c and the yoke 10a may be formed by laminating silicon steel plates. Alternatively, a magnetic material having a high magnetic permeability such as S10C, SS400 permalloy, or ferrite may be used.

  As shown in FIG. 1A, the cable 19 is drawn from the displacement sensor 10 of the load sensor 9. At this time, as shown in a plan view of FIG. 1B, the displacement sensor 10 is press-fitted after the cable 19 is aligned with the position of the U-shaped notch 20 provided at the outboard side end of the outer member 1. Thus, the displacement sensor 10 can be easily attached to the outer member 1 without being obstructed by the cable 19. In order to seal the U-shaped notch 20, the cable 19 is inserted through an elastic member 21 (for example, a rubber material) that matches the shape of the U-shaped notch 20, and then the elastic member 21 becomes U-shaped. It is inserted into the letter-shaped notch 20. In order to further improve the sealing performance of the U-shaped cutout 20 portion, heat fixation such as an adhesive or heat welding may be used. After this process, the metal ring 7 b (FIG. 1B) of the seal 7 is press-fitted and fixed to the outer periphery of the outer member 1. Thereby, a part of the seal metal ring 7b overlaps with the U-shaped notch 20, and the waterproofness of the U-shaped notch 20 can be enhanced. Further, when the elastic member 21 has a thickness that protrudes from the outer diameter surface of the outer member 1, the waterproof effect can be further enhanced. As another waterproof measure, an elastic member such as rubber may be interposed over the entire circumference at the contact portion between the metal ring 7b of the seal 7 and the outer member 1. Note that the method of pulling out the cable 19 and the sealing process are not limited thereto.

  The stem portion 14 of the constant velocity joint outer ring 13a is shorter than the length of the inner diameter hole 29 of the hub wheel 2A, and the portion 2d on the outboard side of the spline coupling portion of the stem portion 14 in the inner diameter hole 29 of the hub wheel 2A. Is larger than the inner diameter of the spline groove 2b. As a result, the rigidity of the hub wheel 2A, a part of which becomes the detected portion 11 of the load sensor 9, is reduced within a range that does not affect the strength. With this structure, the axis of the hub wheel 2A is easily inclined, and the sensitivity of the load sensor 9 can be improved.

FIG. 3 shows a detection circuit example of the load sensor 9. Here, load detection when a vertical load is applied to the wheel bearing 18 will be described as an example. This detection circuit comprises a first series circuit 22 comprising a coil 10b1 and a resistor and a second series circuit unit 23 comprising a coil 10b3 and a resistor connected in parallel. An AC voltage of several tens of kHz is applied from the transmitter 24 to the first series circuit unit 22 and the second series circuit unit 23 connected in parallel thereto. The divided voltage applied to the first coil 10 b 1 is converted into a DC voltage by the rectifier 25 and the low-pass filter 26 and input to the first input terminal of the differential amplifier 27. The divided voltage applied to the second coil 10 b 3 is also converted into a DC voltage by another rectifier 25 and a low-pass filter 26 and input to the second input terminal of the differential amplifier 27. The differential amplifier 27 amplifies and outputs the difference between these two inputs. This output is obtained by detecting the load or moment load applied to the hub wheel 2A.
Instead of the series circuits 22 and 23, a resonance circuit of a capacitor 28 and a coil 10b1 (10b3) may be used as shown in FIG. In this example, the rectifier 25 is replaced with a diode, and the low-pass filter 26 is replaced with a smoothing capacitor. In this way, the sensitivity of displacement detection can be increased by using the resonance circuit.

  Next, the load detection operation in the wheel bearing 18 having the above configuration will be described. When the vehicle load on the wheel bearing 18 changes or when a moment load in the vertical direction is applied to the wheel mounting flange 2a during cornering, the contact surface between the rolling element 3 and the rolling surfaces 4 and 5 of the wheel bearing 18 moves. Thus, the hub wheel 2A has an inclined axis. At this time, if the yokes 10a1 and 10a3 in the load sensor 9 are fixed to the outer member 1 in the vertical direction of the vehicle body, when the gap between the yoke 10a1 and the detected portion 11 becomes larger, 180 degrees. The gap between the yoke 10a3 provided at the opposed position and the detected portion 11 decreases. If each gap change is processed by the circuit shown in FIG. 3 or 4 using the corresponding coils 10b1 and 10b3, the load applied to the wheel bearing 18 can be estimated from the inclination angle of the hub wheel 2A.

In addition, even when a moment in a direction rotated 90 degrees, that is, in a direction parallel to the tire installation surface is applied to the wheel mounting flange 2a, if the same processing is performed using the coils 10b2, 10b4, the horizontal Measure direction load or moment load.
Further, by taking the output difference between the two displacement sensors 10A, 10C (10B, 10D) at the positions opposed to each other by 180 degrees in this way, the output fluctuation due to the eccentricity of the hub wheel 2A is canceled and the sensitivity is doubled. it can.

  Thus, in the wheel sensor built-in wheel bearing of this embodiment, the outer member 1 and the inner member 2 are located between the wheel mounting flange 2a of the hub wheel 2A of the inner member 2 and the rolling element 3. Since a plurality of displacement sensors 10 for measuring the gap between the two are arranged in the circumferential direction, the load sensor 9 can be compactly installed in the vehicle, and the load applied to the wheels can be detected stably. Further, since the displacement sensor 10 can be incorporated inside the bearing of the seal 7, there is no aging of the displacement sensor 10 environmentally, and it can withstand long-term use.

  The electrical processing by the detection circuit may be performed on a circuit board (not shown) provided on the outer member 1 or may be performed by fixing the circuit board to a knuckle (not shown). Furthermore, the circuit board can be built in the ECU (electric control unit) side of the automobile. The torque information processed by the detection circuit in this way can also be transmitted wirelessly to a receiving means on the vehicle body side by a transmitting means (not shown). In this case, it is also possible to wirelessly supply power to the circuit board on which the detection circuit is mounted. The load output obtained here is taken into the ECU as information, and can be applied to driving stability control of an automobile and transmission of road surface information in a steer-by-wire system.

  5 and 6 show another configuration example of the load sensor 9 in FIG. 2, and the load detection method is the same as the example of FIG. In FIG. 5, a plurality of yokes 10a11 to 10a13, 10a21 to 10a23, 10a31 to 10a33, 10a31 to 10a33, 10a41 to 10a43 arranged in the circumferential direction at a mechanical angle of 90 degrees or less (here, 30 degrees) on the magnetic ring plate 10c. Are integrally formed by protruding toward the inner diameter side. Coils 10b11 to 10b13, 10b21 to 10b23, 10b31 to 10b33, and 10b41 to 10b43 are wound around these yokes, respectively. One set of yokes 10a11 to 10a13 and coils 10b11 to 10b13 wound around these yokes constitute one displacement sensor 10A, and the windings of the coils 10b11 to 10b13 are connected and processed as one coil. . Similarly, another set of yokes 10a21 to 10a23 and coils 10b21 to 10b23 wound around these yokes constitute another displacement sensor 10B, and the windings of the coils 10b21 to 10b23 are connected. And processed as one coil. Further, another set of yokes 10a31 to 10a33 and coils 10b31 to 10b33 wound around these yokes constitute another displacement sensor 10C, and the windings of the coils 10b31 to 10b33 are connected to each other. Treated as a coil. Further, another set of yokes 10a31 to 10a33 and coils 10b31 to 10b33 wound around these yokes constitute another displacement sensor 10C, and the windings of the coils 10b31 to 10b33 are connected to each other. Treated as a coil. Another set of yokes 10a41 to 10a43 and coils 10b41 to 10b43 wound around these yokes constitute another displacement sensor 10D, and the windings of the coils 10b41 to 10b43 are connected to form one coil. It is processed.

  As described above, in this load sensor 9, the variation in sensor output due to the rotational vibration of the hub wheel 2 </ b> A is suppressed by increasing the circumferential range in which one displacement sensor 10 faces the detected portion 11.

In FIG. 6, in the configuration of the load sensor 9 shown in FIG. 2, the width in the circumferential direction opposite to the detected portion 11 of each one of the yokes 10a1 to 10a4 is widened, and the purpose is the same as in FIG. is there. In this case, the circumferential width of each of the yokes 10a1 to 10a4 is 90 degrees or less, and is set to a circumferential width close to approximately 90 degrees, for example, about 70 degrees or more within a range in which winding can be performed between adjacent yokes.
In this way, by widening the circumferential angle of the tips of the yokes 10a1 to 10a4, it is possible to average the sensor output and reduce the eccentric error.

7 and 8 show another embodiment of the present invention. The load sensor built-in wheel bearing of this embodiment is different from the first embodiment shown in FIGS. 1 to 6 in that the displacement sensor 10 of the load sensor 9 is replaced with a displacement sensor 30 (here, 4 of 30A-30D).
In this example, a plurality of through holes 31a penetrating in the radial direction are provided at four positions on the top, bottom, left, and right, which are positions separated by 90 degrees in the mechanical angle of the nonmagnetic ring member 31. Each of the displacement sensors 30 (30A to 30D) includes a cylindrical yoke 30a (30a1 to 30a4) made of a magnetic material inserted and fixed in each of the through holes 31a, and a coil 30b (30b1 to 30b4) wound around each yoke 30a. ) And each.

  The cylindrical yoke 30a is made of a magnetic body having an E-shaped cross section having an axial center that is coaxial with the axial center of the through hole 31a and faces the detected portion 11 on the outer diameter surface of the hub wheel 2A. 30b is wound. The load detection method by the load sensor 9A is the same as that in the first embodiment. Also in this case, similarly to the load sensor 9 of FIG. 5, the number of the displacement sensors 30 arranged in the circumferential direction is increased to be divided into a plurality of sets, and the windings of the plurality of coils 30b of each set are connected to form one sensor. You may process as a coil.

  FIG. 9 shows still another embodiment of the present invention. The load sensor built-in wheel bearing of this embodiment uses an axial type load sensor 9B in place of the radial load sensor 9 in the first embodiment shown in FIGS. The load sensor 9B of this example is directed to the inboard side of the displacement sensor 40, which is a detection part provided at the end of the outer member 1 on the outboard side, and the wheel mounting flange 2a that the displacement sensor 40 faces in the axial direction. It is comprised by the to-be-detected part 41 on the side surface 2c, and is set as the structure which measures the clearance gap between the outer member 1 and the to-be-detected part 41. FIG. The displacement sensor 40 has a shaft so as to face the detected portion 41 at a predetermined interval at a plurality of locations in the circumferential direction of the ring plate 40c made of a magnetic material (for example, four locations separated by a mechanical angle of 90 degrees). It consists of a plurality of yokes 40a integrally formed so as to protrude in the direction, and a plurality of coils 40b wound around these yokes 40a. The load detection method by the load sensor 9B is the same as that of the load sensor 9 in the first embodiment, and the load is calculated by detecting the displacement caused by the moment load applied to the wheel mounting flange 2a.

  FIG. 10 shows still another embodiment of the present invention. The load sensor built-in wheel bearing of this embodiment is obtained by changing the coupling configuration of the constant velocity joint 13 and the wheel bearing 18 in the embodiment shown in FIG. In this embodiment, the constant velocity joint outer ring 13a is fastened and fixed to the hub wheel 2A by screwing the nut 42 into the male screw portion 14c provided at the tip of the stem portion 14 of the constant velocity joint outer ring 13a. The spline groove 2b of the inner diameter hole 29 of the hub wheel 2A is formed from the inboard side end to a corresponding position of the wheel mounting flange 2a on the outboard side. A spline groove 14b formed on the outer peripheral surface of the stem portion 14 is spline fitted to the spline groove 2b. From the viewpoint of sensor sensitivity, the structure of the first embodiment in which the stem portion 14 is not provided in the central portion in the radial direction of the wheel mounting flange 2a is preferable because the amount of deformation due to moment load increases. In this embodiment, the load sensor 9B in the embodiment shown in FIG. 9 is used. However, even if the load sensor 9 in the first embodiment shown in FIGS. 7 and another load sensor 9A shown in FIG. 8 may be used.

  11 and 12 show still another embodiment of the present invention. The load sensor built-in wheel bearing according to this embodiment is different from the embodiment shown in FIG. 10 in that the inner ring 2B is clamped and fixed in the axial direction by the caulking portion 2Aa of the hub ring 2A. The inner ring 2B is clamped and fixed in the axial direction by the joint surface 13aa of 13a and the nut 42 that is screwed into the male screw part 14c of the stem part 14 of the constant velocity joint outer ring 13a. The joint surface 13aa of the constant velocity joint outer ring 13a is a portion that is in contact with the caulking portion 2Aa of the hub wheel 2A in the embodiment of FIG. 10, and when the nut 42 is tightened, the joint surface 13aa is connected to the inner ring 2B. The inner ring 2B is clamped and fixed in the axial direction with respect to the hub ring 2A by being pressed against the board-side width surface.

  Moreover, in this embodiment, it replaces with the load sensor 9B in embodiment of FIG. 10, and the rotation sensor 43 and the load sensor 9 are provided in the inboard side edge part of the bearing 18 for wheels. The rotation sensor 43 includes an encoder 44 and a detection unit 45. The load sensor 9 includes a detected portion 11A composed of an outer diameter surface on the inboard side adjacent to the joint surface 13aa of the constant velocity joint outer ring 13a, and a displacement sensor 10 opposed to the detected portion 11A in the radial direction. Consists of. The configuration of the displacement sensor 10 is the same as that of the displacement sensor 10 of the load sensor 9 in the first embodiment shown in FIGS.

  The encoder 44 of the rotation sensor 43 is attached to the outer periphery of the inboard side end of the inner member 2. The encoder 44 is composed of a magnetic encoder, and a multi-pole magnet 44b is provided on a side plate portion of an annular cored bar 44a having an L-shaped cross section. The encoder 44 is attached to the inner member 2 by press-fitting the cylindrical portion of the cored bar 44a into the outer periphery of the inner ring 2B. The multipolar magnet 44b is a member in which magnetic poles N and S are alternately formed in the circumferential direction, and is made of a rubber magnet, a plastic magnet, a sintered magnet, or the like. In this embodiment, the encoder 44 also serves as a component part of the seal 8 on the inboard side, and a lip portion slidably contacting the inner diameter surface of the outer member 1 is integrally formed with the multipolar magnet 44b.

  The detection unit 45 of the rotation sensor 43 is a magnetic sensor that is arranged to face the encoder 44 in the axial direction and detects the magnetic field of the encoder 44, and is attached to the outer member 1 via the sensor attachment member 46. The detection unit 45 is embedded in a sensor holder 47 made of resin together with the displacement sensor 10 of the load sensor 9. The sensor holder 47 has a cord cover portion 47b extending rearward from the main body portion 47a, and a cord 48 extends from the tip of the cord cover portion 47b.

  The sensor mounting member 46 includes a fitting tube portion 46 a that fits to the outer diameter surface of the outer member 1, and a side plate portion 46 b that contacts the end surface of the outer member 1 and is positioned in the axial direction. The side plate portion 46b is provided with inner and outer facing plate portions 51 and 52 facing each other, and the sensor holder 47 is attached between the inner and outer facing plate portions 51 and 52. The sensor holder 47 is manufactured separately from the sensor attachment member 46 and attached to the sensor attachment member 46. The sensor mounting member 46 includes an inner plate 49 and an outer plate 50 made of two metal plates that overlap each other. The inner and outer opposed plate portions 51 and 52 of the side plate portion 46b are configured on the entire circumference of the inner plate 49 and the outer plate 50, and the cylindrical portion of the outer plate 50 that connects between the opposed plate portions 51 and 52 and the outer peripheral edge thereof. Thus, the side plate portion 46b is formed as a hollow double plate having a U-shaped cross section along the radial direction. In addition, you may provide the opposing board parts 51 and 52 only in a part of circumferential direction of the side board part 46b. Each of the inner plate 49 and the outer plate 50 is made of a pressed product of sheet metal.

  The sensor attachment member 46 is attached to the outer member 1 by press-fitting the fitting tube portion 46 a into the outer diameter surface of the outer member 1. A sheet-like elastic body 53 made of rubber or the like is fixed to the inner diameter surface of the fitting cylinder portion 46 a, and the engaging portion of the inner diameter surface of the elastic body 53 is an engagement groove on the outer diameter surface of the outer member 1. The sensor mounting member 46 can be prevented from coming off by engaging with.

  The opposing plate portions 51 and 52 inside and outside the sensor mounting member 46 have sensor mounting openings 51a and 52a that allow the sensor holder main body portion 47a to penetrate inside and outside, and the detecting portion 45 of the rotation sensor 43 is the inside opposing plate portion 51. The sensor mounting opening 51a is disposed at a position facing the encoder 44 in the axial direction. The displacement sensor 10 of the load sensor 9 is disposed on the inner peripheral edge side of the side plate portion 46 b of the sensor mounting member 46. An elastic body 54 made of a rubber material or the like is sandwiched between the inner plate 49 and the outer plate 50 of the sensor mounting member 46. The elastic body 54 has a sheet shape, and is interposed between the sensor holder 47 and the outer opposing plate portion 52 in the side plate portion 46b. The inner peripheral edge portion of the elastic body 54 is provided so as to cover the outer surface of the outer opposing plate portion 52, and a lip 54a slidably contacting the step surface 13ab facing in the axial direction of the constant velocity joint outer ring 13a is provided on the outer peripheral edge portion of the elastic body 54. It has been. The step surface 13ab is located on the outer diameter side of the joint surface 13aa that presses the end surface of the inner ring 2B of the inner member 2. The outer peripheral surface of the constant velocity joint outer ring 13a is formed in a stepped shape by the joint surface 13aa and the step surface 13ab.

  The detection unit 45 of the rotation sensor 43 and the displacement sensors 10 (here, four of 10A to 10D) of the load sensor 9 are as shown in FIG. Placed in. That is, the detection unit 45 of the rotation sensor 43 is disposed at the upper part in the circumferential direction, and the displacement sensors 10A to 10D of the load sensor 9 are disposed at respective positions (positions 90 degrees apart from each other). The detection unit 45 of the rotation sensor 43 is disposed at a position higher than the displacement sensor 10A in the vertical direction with respect to the bearing center. Further, a sealing elastic body 55 is filled between the detecting portion 45 and the placement portions of the displacement sensors 10A to 10D in the sensor holder 47, and the detection portion 45 and the lead wires of the displacement sensors 10A to 10D are disposed on the outer peripheral side thereof. The lead wire wiring path 56 for wiring is secured.

  In this embodiment, the four displacement sensors 10A to 10D of the load sensor 9 are embedded in the sensor holder 47 together with the detection unit 45 of the rotation sensor 43. However, a part of the displacement sensors 10A to 10D is shown. For example, only the displacement sensor 10 </ b> A arranged at the same position as the detection unit 45 of the rotation sensor 43 may be embedded in the sensor holder 47 together with the detection unit 45 of the rotation sensor 43.

  In the wheel bearing with built-in load sensor of this configuration, the displacement sensor 10 of the load sensor 9 detects a change in the gap between the tip of the displacement sensor 10 and the outer diameter surface of the constant velocity joint outer ring 13a as the detected portion 11A. It is detected as a load applied to the bearing. Moreover, the detection part 45 of the rotation sensor 43 detects the magnetic pole change of the encoder 44 as rotation of a wheel.

  In the case of this configuration, the detection unit 45 of the rotation sensor 43 and the displacement sensor 10 of the load sensor 9 are attached in a sandwiched state between the inner and outer opposing plate parts 51 and 52 provided on the sensor attachment member 46. There is no fear that the detection unit 45 and the displacement sensor 10 will come off, and the attachment can be made reliably and highly reliable. The sensor mounting member 46 is fitted to the outer diameter surface of the outer member 1 by the fitting cylinder portion 46a, and is positioned in the axial direction in contact with the end surface of the outer member 1 by the side plate portion 46b. It can be performed with high accuracy, and the positioning accuracy of the detection unit 45 and the displacement sensor 10 can be excellent. The detection unit 45 of the rotation sensor 43 and the displacement sensor 10 of the load sensor 9 are assumed to have sensor elements embedded in a sensor holder 47 made of resin or the like. Is manufactured separately and attached to the sensor attachment member 46. Therefore, when mounting on bearings of different sizes, the sensor mounting member 46 can be dealt with according to the size of the bearing, and the sensors with the sensor holder 47 can be of different sizes using the same sensor. Compatible with bearings. Therefore, a sensor unit including the sensor (detection unit 45, displacement sensor 10) and sensor mounting member 46 can be manufactured at low cost.

In addition, the sensor mounting member 46 is composed of two inner plates 49 and an outer plate 50 that are overlapped on the inside and outside of each other, so that the operation of sandwiching the sensor holder 47 between the sensor mounting member 46 can be easily performed.
Since the sensor attachment opening 51a is provided on the inner side surface of the side plate portion 46b of the sensor attachment member 46, the detection portion 45 of the rotation sensor 43 can be directly opposed to the encoder 44 without using the side plate portion 46b. . Further, since the sensor attachment opening 52a is provided on the outer side surface of the side plate portion 46b of the sensor attachment member 46, it is easy to draw out the wiring to the outside. When these sensor mounting openings 51a and 52a are provided, the outer periphery of the rotation sensor 43 of the sensor holder 47 is fitted into the sensor mounting openings 51a and 52a, and the rotation of the bearing portion in the radial direction and the circumferential direction is performed. It is also possible to position the sensor 43.

  Although an elastic body 53 is interposed between the opposing plate portion 52 on the outer surface side of the sensor mounting member 46 and the sensor holder 47, an elastic body is provided between the opposing plate portion 51 on the inner surface side and the sensor holder 47. (Not shown) may be interposed. By interposing the elastic body as described above, the sensor holder 47 can be stably mounted without rattling the sensor mounting member 46 and without generating an excessive clamping force.

  The elastic body 53 may also serve as a seal that seals between the inner member 2 and the sensor mounting member 46. For example, the elastic body 53 is configured such that the inner peripheral edge of the elastic body 53 is in sliding contact with the outer peripheral surface of the inner member 2. In this case, the elastic body 53 can be used for both the stable mounting of the sensor and the sealing means, and the sealing performance can be improved without increasing the number of parts. In addition, by sealing the space between the inner member 2 and the sensor mounting member 46 with the elastic body 53 in this manner, foreign matter is not caught between the encoder 44 and the detecting portion 45, and the stone from the road surface is It is prevented from being caught between the encoder 44 and the detection unit 45 by the splash. These functions and effects are not limited to the elastic body 53 provided on the outer facing plate portion 52 side, but also when the elastic body (not shown) is provided on the inner facing plate portion 51. Each effect similar to is obtained.

  FIG. 13 shows still another embodiment of the present invention. In the embodiment shown in FIG. 11 and FIG. 12, the bearing for a wheel with a built-in load sensor of this embodiment is provided with an inner diameter hole 29 in the hub wheel 2A on the outer periphery of the inboard side end of the stem portion 14 in the constant velocity joint outer ring 13a. A guide surface 13ac that fits into the non-formed inner diameter surface 2f of the spline groove 2b at the board side end is formed.

  In this way, by fitting the spline groove non-formed inner diameter surface 2f of the hub wheel inner diameter hole 29 and the guide surface 13ac of the constant velocity joint outer ring stem portion 14, the constant velocity to be detected portion 11A of the load sensor 9 is obtained. It is possible to prevent the joint outer ring 13a from being eccentric due to the spline fitting back and to detect the load with higher accuracy.

(A) is sectional drawing of the bearing for load sensors built-in wheels concerning 1st Embodiment of this invention, (B) is a partial top view of the bearing. It is a cross-sectional view of the load sensor in the bearing. It is a schematic block diagram of the detection circuit of the load sensor in the same bearing. It is a schematic block diagram of the other example of the detection circuit of the load sensor in the same bearing. It is a cross-sectional view of another example of a load sensor in the same bearing. It is a cross-sectional view of still another example of a load sensor in the bearing. It is sectional drawing of the bearing apparatus for load sensor built-in wheels concerning other embodiment of this invention. It is a cross-sectional view of the load sensor in the bearing. It is sectional drawing of the bearing apparatus for load sensor built-in wheels concerning further another embodiment of this invention. It is sectional drawing of the bearing apparatus for load sensor built-in wheels concerning further another embodiment of this invention. It is sectional drawing of the bearing apparatus for load sensor built-in wheels concerning further another embodiment of this invention. It is AA arrow sectional drawing of FIG. It is sectional drawing of the bearing apparatus for load sensor built-in wheels concerning further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 2A ... Hub wheel 2a ... Wheel mounting flange 3 ... Rolling elements 4, 5 ... Rolling surface 7, 8 ... Seal 9, 9A, 9B ... Load sensor 10 ... Displacement sensor 10a ... Yoke 10b ... Coil 10c ... Ring plate 11, 11A ... Detected part 13a ... Constant velocity joint outer ring 14 ... Stem part 29 ... Hub wheel inner diameter hole 30 ... Displacement sensor 30a ... Cylindrical yoke 30b ... Coil 31 ... Ring member 31a ... Through Hole 43 ... Rotation sensor 44 ... Encoder 45 ... Detection part 46 ... Sensor mounting member 46a ... Fitting cylinder part 46b ... Side plate part 51, 52 ... Opposite plate part

Claims (14)

An outer member having a double row rolling surface on the inner peripheral surface, and a double row rolling surface having a hub wheel formed with a wheel mounting flange and facing the rolling surface of the outer member. An inner member, a double row rolling element interposed between both rolling surfaces, and a sealing means for sealing both ends of the outer member and the inner member, and rotatably supporting the wheel with respect to the vehicle body. In wheel bearings,
As a means for detecting a load acting between the flange of the hub wheel and the rolling element and acting on the wheel bearing, one displacement sensor for measuring a gap between the outer member and the inner member is provided in the circumferential direction. A load bearing built-in wheel bearing, wherein a plurality of wheels are arranged.   The load sensor built-in wheel bearing according to claim 1, wherein the displacement sensor takes an output difference between two displacement sensors provided at positions opposed to each other by 180 degrees.   3. The load sensor built-in wheel bearing according to claim 1, wherein the displacement sensor is a reluctance type in which a coil is wound around a magnetic yoke.   4. The method according to claim 1, wherein a plurality of protruding yokes are formed on the inner diameter side of the ring plate made of a magnetic material, coil windings are applied to each yoke, and the coil windings are applied. Load sensor built-in wheel bearing with ring plate fixed to outer member.   5. A sensor coil winding according to claim 1, wherein coil windings wound around a plurality of protruding yokes having a mechanical angle of 90 degrees or less are connected to each other. Load sensor built-in wheel bearing.   5. The circumferential width of any one of claims 1 to 4, wherein the circumferential width of one yoke is 90 degrees or less and is approximately 90 degrees within a range in which a winding can be interposed between adjacent yokes. Load sensor built-in wheel bearing.   6. The magnetic material according to claim 1, wherein the nonmagnetic ring member is formed of a magnetic body having a cross-section E shape having a plurality of holes along the axial center in the radial direction and having a convex portion at the center. A load sensor built-in wheel bearing in which a displacement sensor having a coil winding on the convex portion of the yoke is fixed to the hole of the ring member, and the convex portion of each yoke is opposed to the inner member.   8. The displacement sensor according to claim 1, wherein the displacement sensor is opposed to a hub wheel outer diameter surface formed between a flange surface and a rolling surface of the hub wheel, and the clearance is measured. Load sensor built-in wheel bearing that detects the load based on the result.   8. The load sensor built-in wheel according to claim 1, wherein the displacement sensor detects a load based on a result of measuring a gap between a flange side surface of the hub wheel and an outer member. bearing.   10. The inner member according to claim 1, wherein the inner member has an inner diameter hole, and a stem portion of a constant velocity joint is inserted into the inner diameter hole to couple the inner member and the constant velocity joint. A load sensor built-in wheel bearing, wherein a stem portion of the constant velocity joint is shorter than an axial length of the inner diameter hole of the hub wheel.   11. The load sensor built-in wheel bearing according to claim 1, wherein the displacement sensor is incorporated inside a bearing of the sealing means. An outer member having a double row rolling surface on the inner peripheral surface, an inner member having a double row rolling surface facing the rolling surface of the outer member, and a compound interposed between the rolling surfaces. In a wheel bearing comprising a row of rolling elements and rotatably supporting the wheel with respect to the vehicle body,
An encoder attached to the end of the inner member, and a rotation sensor having a detection portion attached to the end of the outer member opposite to the encoder;
A displacement sensor having a detection unit attached to a joint that is spline-fitted to the inner member;
A sensor mounting member having a fitting tube portion that fits to the outer diameter surface of the outer member and a side plate portion that is positioned in the axial direction in contact with the end surface of the outer member is provided, and the side plate of the sensor mounting member The load sensor-equipped wheel bearing is provided with inner and outer facing plate portions facing each other, and the rotation sensor and the displacement sensor are sandwiched between the inner and outer facing plate portions.   13. The load according to claim 12, wherein both the rotation sensor and the displacement sensor attached in a sandwiched state between the inner and outer opposing plate portions are arranged at a vertical position relative to the bearing center and at both horizontal positions. Bearing for sensor built-in wheel.   14. The load sensor built-in wheel bearing according to claim 12, wherein a plurality of displacement sensors are provided, and at least one of the plurality of displacement sensors is resin-molded together with the rotation sensor.

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