JP2008074136A - Bearing device for wheel with built-in sensor in in-wheel motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel with a built-in sensor in an in-wheel motor, with low costs at the time of mass production, capable of installing a sensor for detecting a load to a vehicle compactly, and detecting a force acting on a ground point of a wheel and a road face with good sensitivity. <P>SOLUTION: In this bearing device for a wheel, an output shaft 24 of an electric motor B and a hub 2 of a wheel of a vehicle are connected with a same shaft via a decelerator C or directly, and a rolling-type bearing A supporting the hub 2 is provided. A sensor unit 51 for measuring a force of at least one of three axial forces in upward and downward, rightward and leftward, and forward and backward directions perpendicular to each other at a ground point of the wheel mounted to the hub 2 and the road by detecting distortion of a static side trajectory wheel 1 of the bearing A. The sensor unit 51 comprises a sensor mounting member 52, and a distortion sensor 53 mounted to the sensor mounting member 52, and both ends of the sensor mounting member 52 are mounted to two portions separated in perimeter direction of the static side trajectory wheel 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-wheel motor-equipped wheel bearing device in which a hub bearing, a speed reducer, and an electric motor are combined, and more particularly to a device provided with a sensor that detects a load applied to the hub bearing.

As a wheel bearing device for a vehicle such as an electric vehicle, an in-wheel type motor-integrated wheel bearing device in which a hub bearing, a speed reducer, and an electric motor are combined has attracted attention (for example, Patent Documents 1 and 2). When this in-wheel type motor-equipped wheel bearing device is used as a driving wheel of an electric vehicle, each driving wheel can be individually driven to rotate, so that a large-scale power transmission mechanism such as a propeller shaft and a differential is not required. Can be made lighter and more compact.
JP 2005-7914 A JP-A-5-332401 (FIGS. 1-3) Special table 2003-530565 gazette

  When putting in-wheel motor-equipped wheel bearing devices into practical use, it is of course essential to measure the rotational speed of each wheel for traveling speed control, etc. It is also conceivable to measure the load acting on each wheel during vehicle travel and to control the vehicle attitude from the measurement result. For example, a large load is applied to the outer wheel in cornering, and the load applied to each wheel is not uniform. In addition, even when the load is uneven, the load applied to each wheel is uneven. For this reason, if the load applied to the wheel can be detected at any time, the suspension control etc. is controlled in advance based on the detection result, thereby controlling the attitude during vehicle travel (preventing rolling during cornering, preventing the front wheel from sinking during braking, It is possible to prevent subsidence due to uneven load capacity.

  In addition, when steer-by-wire is introduced in the future and the system becomes a system in which the axle and the steering are not mechanically coupled, it is required to detect the axle direction load and transmit the road surface information to the handle held by the driver.

In addition, in general wheel bearings used in engine-driven automobiles, in order to measure the load acting on the wheels, a strain gauge is attached to the outer ring of the bearing to detect distortion. (For example, Patent Document 3).
However, 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. For this reason, attaching a strain gauge to the outer ring as in Patent Document 3 has a problem of low productivity and high cost during mass production. 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 an in-wheel type motor built-in sensor in which a load detecting sensor can be compactly installed in a vehicle, and the force acting on the contact point between the wheel and the road surface can be detected with high sensitivity, and the cost during mass production is low. It is providing the bearing apparatus for a wheel with a wheel.

  The in-wheel motor-equipped sensor-equipped wheel bearing device according to the present invention is a rolling type in which an output shaft of an electric motor and a vehicle wheel hub are connected coaxially via a speed reducer or directly and support the hub. In the wheel bearing device provided with the above bearing, by detecting the distortion of the stationary-side bearing ring of the bearing, the wheel mounted on the hub and the ground contact point of the road surface are perpendicular to each other, right and left directions, and A sensor unit that measures force in at least one of the forces in the three axial directions in the front-rear direction is provided, and the sensor unit includes a sensor attachment member and a strain sensor attached to the sensor attachment member, Both ends of the sensor mounting member are mounted at two locations separated in the circumferential direction of the stationary side race.

When an external force acting on the contact point between the wheel and the road surface is applied to the bearing as the vehicle travels, a load due to the external force is transmitted from the rotating raceway of the bearing to the stationary raceway, and the stationary raceway is deformed. The deformation causes distortion in 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 external force is obtained in advance through experiments and simulations, the force acting on the contact point between the wheel and the road surface can be detected from the output of the strain sensor. The force acting on the contact point between the wheel and the road surface is a combination of the forces in the three axial directions of the vertical direction, the left and right direction, and the front and rear direction orthogonal to each other at the contact point. A force in at least one of the directions is detected. This detected force can be used for vehicle attitude control.
The degree of deformation of the stationary bearing ring of the bearing varies depending on each part in the circumferential direction. When both ends of the sensor mounting member are mounted at two locations separated in the circumferential direction of the stationary side race, the sensor mounting member is mounted at a location where deformation is large, with the side mounted at a location where deformation is small serving as a fulcrum. The side is greatly deformed. For this reason, the strain sensor mounting portion of the sensor mounting member causes even greater strain, and the strain sensor can detect the strain of the stationary-side track ring with high sensitivity.
Since the wheel bearing has a configuration in which a sensor unit including a sensor mounting member and a strain sensor mounted on the sensor mounting member is mounted on the stationary-side raceway of the bearing, 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 stationary-side bearing ring, mounting a strain sensor on the sensor mounting member can provide excellent mass productivity and reduce costs.

  In the present invention, the wheel bearing device includes an outer member having a double-row rolling surface formed on the inner periphery, and an inner member having a rolling surface facing the rolling surface of the outer member. When the outer member is a stationary raceway, the sensor unit is provided on the outer member.

Of the contact fixing portions of the sensor mounting member, the first contact fixing portion is at least one of forces in three axial directions in the vertical direction, the horizontal direction, and the front-rear direction orthogonal to each other at the contact point between the wheel and the road surface. It is preferably fixed at a location that is greatly deformed in the radial direction as compared to other locations on the stationary side raceway due to directional force.
The degree of deformation in the radial direction due to the force acting on the ground contact point between the wheel and the road surface varies depending on each part in the circumferential direction. According to the analysis result, the radial deformation of the stationary-side raceway due to the axial force acting on the contact point between the wheel and the road surface is greatest at the directly above position on the opposite road surface side and the directly below position on the road surface side. When the first contact fixing portion is fixed at a location that is largely deformed in the radial direction as compared with other locations on the stationary side raceway as described above, the sensor mounting member is a second contact fixing that is less deformed. The first contact fixing part is greatly deformed with a large deformation of the stationary side race. For this reason, the strain sensor mounting portion of the sensor mounting member generates a larger strain, and the strain sensor can detect the strain of the stationary side race ring with higher sensitivity.

Of the contact fixing portions, the second contact fixing portion is fixed at a position where the first contact fixing portion is fixed at the ground contact point between the wheel and the road surface, and in a vertical direction, a horizontal direction, and The direction of the radial distortion generated by the force in at least one direction among the forces in the three axial directions in the front-rear direction may be different from the normal direction.
If the fixed part of the second contact fixing part and the fixed part of the first contact fixing part are different from each other in the direction of radial distortion of the stationary side race, the distortion in both directions is added. As a result, the deformation of the stationary side race ring is largely transmitted to the sensor mounting member, so that even greater strain can be detected and the strain of the stationary side race ring can be detected with high sensitivity.

The sensor unit may be plural.
When there are a plurality of sensor units, a plurality of strain sensors detect a plurality of strains of the stationary-side track ring, and a force acting on a contact point between the wheel and the road surface is detected from the outputs of the plurality of strain sensors. Therefore, the detection accuracy of the force acting on the contact point between the wheel and the road surface is improved.

The sensor unit is preferably arranged at a position on the outboard side with respect to the rolling surface on the outboard side in the stationary side fixed wheel.
According to the analysis and test results, both the radial strain and circumferential strain of the stationary side raceway have positive and negative directionality to the strain due to the positive and negative loads due to the force acting on the contact point between the wheel and the road surface. Only the part on the outboard side of the ring. Therefore, in order to detect the positive / negative direction of the load, it is necessary to arrange the sensor unit at a position on the outboard side of the stationary side race.

  The in-wheel motor-equipped sensor-equipped wheel bearing device according to the present invention is a rolling type in which an output shaft of an electric motor and a vehicle wheel hub are connected coaxially via a speed reducer or directly and support the hub. In the wheel bearing device provided with the above bearing, by detecting the distortion of the stationary-side bearing ring of the bearing, the wheel mounted on the hub and the ground contact point of the road surface are perpendicular to each other, right and left directions, and A sensor unit that measures force in at least one of the forces in the three axial directions in the front-rear direction is provided, and the sensor unit includes a sensor attachment member and a strain sensor attached to the sensor attachment member, Since both ends of the sensor mounting member are mounted at two locations separated in the circumferential direction of the stationary-side track ring, the load detection center is compactly mounted on the vehicle. And can be installed to support, the force acting on the ground point of the wheels and the road surface with high sensitivity can be detected. 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.

  A first embodiment of the present invention will be described with reference to FIGS. This in-wheel type sensor-equipped wheel bearing device with a built-in in-wheel motor includes a hub bearing A that rotatably supports a wheel hub, an electric motor B as a rotational drive source, and a speed reduction of the rotation of the electric motor B. It is a combination of a reduction gear C that transmits. In this embodiment, the hub bearing A is a third generation type inner ring rotating type in which the inner member of the bearing forms part of the hub. 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.

  As shown in FIG. 1, the hub bearing A includes an outer member 1 in which double-row rolling surfaces 3 are formed on the inner periphery, and an inner member in which rolling surfaces 4 that face the respective rolling surfaces 3 are formed. 2 and double row rolling elements 5 interposed between the rolling surfaces 3 and 4 of the outer member 1 and the inner member 2. The hub bearing A is a double-row angular ball bearing type, and the rolling elements 5 are formed 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. The end of the bearing space between the outer member 1 and the inner member 2 is sealed with a seal member 7.

The outer member 1 is a stationary raceway, and has a flange 1a attached to the casing 33b on the outboard side of the speed reducer C on the outer periphery, and the whole is an integral part. The flange 1a is provided with mounting holes 14 at a plurality of locations in the circumferential direction. The outer member 1 is attached to the casing 33b by the attachment bolt 15 inserted through the attachment hole 14.
The inner member 2 serves as a rotating raceway, and the outboard side member 9 having a hub flange 9a for attaching a wheel and the outer side of the outboard side member 9 are fitted on the outer side of the outboard side member and caulked. And the inboard side material 10 integrated with the outboard side material 9. The rolling surface 4 of each said row | line | column is formed in these outboard side materials 9 and inboard side materials 10. FIG. A through hole 11 is provided at the center of the inboard side member 10. The hub flange 9a is provided with insertion holes 17 for hub bolts 16 at a plurality of locations in the circumferential direction. In the vicinity of the root portion of the hub flange 9a of the outboard side member 9, a cylindrical pilot portion 13 for guiding a wheel and a braking component (not shown) protrudes toward the outboard side. A cap 18 that closes the outboard side end of the through hole 11 is attached to the inner periphery of the pilot portion 13.

  The electric motor B is an axial gap type in which an axial gap is provided between a stator 23 fixed to a cylindrical casing 22 and a rotor 25 attached to an output shaft 24. The output shaft 24 is cantilevered by two bearings 26 on the cylindrical portion of the casing 33a on the inboard side of the reduction gear C. The inboard side end of the gap between the output shaft 24 and the casing 33 a is sealed with a seal member 27. A cap 28 is attached to the opening on the inboard side of the casing 22.

  As shown in FIGS. 1 and 2, the speed reducer C is configured as a cycloid speed reducer. That is, the speed reducer C has two curved plates 34a and 34b formed with wavy trochoidal curves with a smooth outer shape, mounted on the eccentric portions 32a and 32b of the input shaft 32 via bearings 35, respectively. A plurality of outer pins 36 interposed between the inboard side and the outboard side casings 33a and 33b guide the eccentric movement of the curved plates 34a and 34b on the outer peripheral side, and also the inboard side member 10 of the inner member 2. A plurality of inner pins 38 attached to is fitted into and engaged with a plurality of through holes 39 provided in the curved plates 34a and 34b. The input shaft 32 is spline-coupled with the output shaft 24 of the electric motor B so as to rotate integrally. The input shaft 32 is supported at both ends by two bearings 40 on the casing 33a on the inboard side and the inner diameter surface of the inboard side member 10 of the inner member 2.

  When the output shaft 24 of the electric motor B rotates, the curved plates 34a and 34b attached to the input shaft 32 that rotates integrally with the output shaft 24 perform an eccentric motion. The eccentric motion of each of the curved plates 34a and 34b is transmitted as rotational motion to the inner member 2 which is a wheel hub by the engagement of the inner pin 38 and the through hole 39. The rotation of the inner member 2 is decelerated with respect to the rotation of the output shaft 24. For example, a reduction ratio of 1/10 or more can be obtained with a single-stage cycloid reducer.

  The two curved plates 34a and 34b are mounted on the eccentric portions 32a and 32b of the input shaft 32 so as to cancel the eccentric motion with respect to each other, and are respectively attached to both sides of the eccentric portions 32a and 32b. A counterweight 41 that is eccentric in the direction opposite to the eccentric direction of each of the eccentric portions 32a and 32b is mounted so as to cancel the vibration caused by the eccentric movement of each of the curved plates 34a and 34b.

  As shown in FIG. 3, bearings 42 and 43 are mounted on the outer pins 36 and the inner pins 38. The outer rings 42a and 43a of the bearings 42 and 43 are respectively connected to the outer circumferences of the curved plates 34a and 34b and the outer rings 42a and 34b, respectively. It comes into rolling contact with the inner periphery of the through hole 39. Therefore, the contact resistance between the outer pin 36 and the outer periphery of each curved plate 34a, 34b and the contact resistance between the inner pin 38 and the inner periphery of each through hole 39 are reduced, and the eccentric motion of each curved plate 34a, 34b is smooth. Can be transmitted to the inner member 2 as a rotational motion.

  This wheel bearing device is fixed to the vehicle body via a knuckle, a suspension (not shown) or the like attached to the outer periphery of the casing 33b of the reduction gear C or the casing 22 of the electric motor B.

  As shown in FIGS. 1 and 4, a sensor unit 51 is provided on the inner periphery of the outer member 1 of the hub bearing A for measuring the force acting on the contact point between the wheel and the road surface. The axial position is between the seal member 7 and the rolling surface 3. As shown in detail in FIG. 5, the sensor unit 51 includes a sensor mounting member 52 and a strain sensor 53 that measures the strain of the sensor mounting member 52. The sensor mounting member 52 has a substantially arc shape that is elongated in the circumferential direction along the inner peripheral surface of the outer member 1, and contact fixing portions 52 a and 52 b that project to the outer peripheral side of the arc are formed at both ends thereof. Further, a notch 52c that opens to the outer peripheral side of the arc is formed at the center of the sensor mounting member 52, and the strain sensor 53 is affixed to the inner peripheral surface of the arc that is located at the back of the notch 52c. Yes. The cross-sectional shape of the sensor mounting member 52 is, for example, a rectangular shape, but may be various other shapes.

The sensor unit 51 is fixed to the inner periphery of the outer member 1 by the contact fixing portions 52 a and 52 b of the sensor mounting member 52 so that the longitudinal direction of the sensor mounting member 52 faces the circumferential direction of the outer member 1. The contact fixing portions 52a and 52b are fixed to the outer member 1 by fixing with bolts or bonding with an adhesive. At locations other than the contact fixing portions 52 a and 52 b of the sensor mounting member 52, a gap is generated between the sensor mounting member 52 and the inner peripheral surface of the outer member 1. The first contact fixing portion 52a, which is one of the contact fixing portions 52a and 52b, is the outer member 1 at a circumferential position where the outer member 1 is most greatly deformed in the radial direction by a load acting on the outer member 1. Fixed to. The second contact fixing portion 52b is fixed at a location where there is less deformation in the radial direction than the fixed location.
In the case of this embodiment, the fixing location of the first contact fixing portion 52a is the position directly above the entire circumference of the outer member 1 (the position on the opposite road surface side), and the fixing location of the second contact fixing portion 52b is The position is several tens of degrees from the position just above, for example, about 30 to 40 degrees below.

  The sensor mounting member 52 is preferably one that does not undergo plastic deformation at the maximum expected value of the force acting on the contact point between the wheel and the road surface. As a material of the sensor mounting member 52, a metal material such as copper, brass, aluminum or the like can be used in addition to a steel material.

Various types of strain sensors 53 can be used. For example, a metal foil strain gauge is used. When the strain sensor 53 is composed of a metal foil strain gauge, the sensor mounting member 52 is a strain sensor in consideration of the durability of the metal foil strain gauge even when the maximum external force expected on the hub bearing A is applied. The strain amount of 53 is preferably 1500 microstrain or less.
In addition, when the strain sensor 53 is formed of a semiconductor strain gauge, the sensor mounting member 52 is a strain sensor in consideration of the durability of the semiconductor strain gauge even when the maximum external force expected on the hub bearing A is applied. It is preferable that the strain amount of 53 is 1000 microstrain or less.

  As shown in FIG. 1, external force calculation means 55 and abnormality determination means 56 are provided as means for processing the output of the strain sensor 23 of the sensor unit 21. These means 55 and 56 may be provided in an electronic circuit device (not shown) such as a circuit board attached to the outer member 1 or the like of the hub bearing A, or may be an electric control unit of an automobile. (ECU) may be provided.

The operation of the in-wheel motor-equipped sensor-equipped wheel bearing device having the above-described configuration will be described. When the electric motor B is driven to rotate, the rotation of the output shaft 24 of the electric motor B is decelerated and transmitted to the inward member 2 that is a wheel hub via the speed reducer C, and the vehicle rotates to rotate the wheel. . When the vehicle travels, external force is applied to the wheels from the contact points between the wheels and the road surface. The external force is a combination of forces in the three axial directions of the vertical direction, the horizontal direction, and the front-rear direction orthogonal to each other.
When a load is applied to the inner member 2 that is a hub by an external force applied to the wheel, the outer member 1 is deformed via the rolling elements 5, and the deformation is a sensor attached to the inner periphery of the outer member 1. The sensor mounting member 52 is deformed by being transmitted to the mounting member 52. The strain of the sensor mounting member 52 is measured by the strain sensor 53. At this time, the sensor mounting member 52 is deformed in accordance with the radial deformation of the fixing portion of the sensor mounting member 52 in the outer member 1, but the sensor mounting member 52 has an arc shape compared to the outer member 1 and has a notch portion. Since the rigidity is lowered at the position of the notch 52 c provided in the sensor mounting member 52, a strain larger than the strain of the outer member 1 appears. For this reason, even the slight distortion of the outer member 1 can be accurately detected by the distortion sensor 53.

Of the two contact fixing portions 52a and 52b of the sensor mounting member 52, the first contact fixing portion 52a is radial compared to other portions of the outer member 1 due to the force acting on the ground contact point between the wheel and the road surface. It is preferable to be attached at a location where the directional deformation is significant. The outer member 1 differs in the degree of radial deformation due to the external force depending on each part in the circumferential direction. According to the result of FEM (finite element method) analysis, the radial deformation of the outer member 1 with respect to the axial force acting on the contact point between the wheel and the road surface is the true position in the opposite road surface side and the road surface side, that is, in the vertical direction. The upper position and the directly lower position are the largest. In this embodiment, since the first contact fixing portion 52a is arranged at the position directly above the vertical direction, which is the position where the radial deformation of the outer member 1 is greatest, the sensitivity of the outer member 1 is improved. Distortion can be detected.
That is, when the first contact fixing portion 52a is attached to a location that is greatly deformed in the radial direction as compared with other locations in the outer member 1, the sensor attachment member 52 is a second contact fixing portion that is less deformed. 52b becomes a fulcrum, and the first contact fixing portion 52a is greatly deformed as the outer member 1 is largely deformed. Therefore, the mounting position of the strain sensor 53 of the sensor mounting member 52 causes a greater strain, and the strain sensor 53 can detect the strain of the outer member 1 with higher sensitivity.

  Of the contact fixing portions 52a and 52b, the second contact fixing portion 52b is different from the first contact fixing portion 52a in the direction of radial distortion caused by the force acting on the contact point between the wheel and the road surface. It is good also as a place where forward and backward differ. For example, at the position above the right lateral position of the outer member 1 (position 90 degrees above the road surface position) and below the right lateral position (position close to the road surface), the grounding point of the wheel and the road surface The direction of the radial deformation of the outer member 1 with respect to the acting axial force is different in the forward and reverse directions. When the first contact fixing part 52a is located directly above the outer member 1 (on the opposite road surface side), if the second contact fixing part 52b is located below the right lateral position of the outer member 1, both contacts The directions of deformation of the outer member 1 in the fixing portions 52a and 52b are different from each other. As described above, when the second contact fixing portion 52b and the first contact fixing portion 52a are different from each other in the direction of the radial distortion of the outer member 1, the distortion on both sides is added. As a result, the deformation of the outer member 1 is largely transmitted to the sensor mounting member 52, so that a larger strain can be detected and the strain of the outer member 1 can be detected with higher sensitivity.

The axial position at which the sensor unit 51 is attached to the outer member 1 is the outer board side position of the outer member 1 as compared to the outer board side rolling surface 3 of the outer member 1, as in the embodiment. The position between the three and the inboard side rolling surface 3 may be the inboard side position, but if it is the outboard side position from the outboard side rolling surface 3, depending on the direction of the load Thus, positive and negative directionality occurs in the strain, and the positive and reverse directions of the load can be detected.
According to FEM analysis and test results, the radial strain and the circumferential strain of the outer member 1 are classified into the three locations on the outer member 1 that have positive and negative directions in the strain due to the positive / negative of the load due to the external force. Of the positions, only the part on the outboard side. Therefore, in order to detect the positive / negative direction of the load, it is necessary to arrange the sensor unit 51 at a position on the outboard side in the outer member 1.
When the sensor unit tot 51 is attached to the outboard side position, the direction of distortion is reversed on both sides in the circumferential direction at the position directly above, so the first contact fixing portion 52a and the second contact fixing portion 52b are connected to each other. Displacement can also be detected with high sensitivity by disposing them on both sides of the position directly above.

  The force (external force) acting on the contact point between the wheel and the road surface can be detected from the strain value thus detected. Since the change in strain differs depending on the direction and magnitude of the external force, the external force acting on the contact point between the wheel and the road surface can be calculated if the relationship between the strain and the external force is obtained in advance through experiments and simulations. The external force calculation means 55 calculates the external force that acts on the contact point between the wheel and the road surface from the output of the strain sensor 53 based on the relationship between the strain and the external force that has been obtained and set in advance through experiments and simulations.

  The abnormality determination unit 56 outputs an abnormality signal to the outside when it is determined that the force acting on the wheel and the contact point of the road surface thus calculated exceeds a set allowable value. This abnormality signal can be used for vehicle attitude control. In addition, if a force acting on the contact point between the wheel and the road surface is output in real time, a finer attitude control is possible.

  This wheel bearing device is configured to attach the sensor unit 51 including the sensor attachment member 52 and the strain sensor 53 attached to the sensor attachment member 52 to the outer member 1 which is a component of the hub bearing A. These sensors can be installed in a compact vehicle. Since the sensor attachment member 52 is a simple part that can be attached to the outer member 1, by attaching the strain sensor 53 to the sensor attachment member 52, the sensor attachment member 52 can be excellent in mass productivity, and the cost can be reduced.

  As shown in FIG. 6, the sensor units 51 may be provided at two locations. This makes it possible to detect a load with higher accuracy. Similarly, by providing the sensor unit 51 at a plurality of three or more locations, it becomes possible to detect a load with higher accuracy. At that time, when it is difficult to install a plurality of sensor units 21 due to space reasons or the like, as shown in FIG. 7, the two contact sensor fixing parts fixed to the inner periphery of the outer member 1 are arranged as two sensor units. 51 may be shared. Further, as shown in FIGS. 8 and 9, the sensor unit 51 may be provided on the outer periphery of the outer member 1.

  FIG. 10 shows a second embodiment of the present invention. In this embodiment, the electric motor B is a radial gap type in which a radial gap is provided between a stator 103 fixed to the casing 102 and a rotor 105 attached to the output shaft 104. The output shaft 104 is splined to the input shaft 32 of the speed reducer C. Except for the electric motor B, the configuration is the same as that of the first embodiment. Also in the second embodiment, the sensor unit 51 similar to the above is provided on the inner periphery of the outer member 1 of the hub bearing A. As a result, it is possible to control the posture of the vehicle by measuring the force acting on the contact point between the wheel and the road surface.

  Also in the case of the second embodiment, as shown in FIG. 11, a sensor unit 51 may be provided on the outer periphery of the outer member 1 of the hub bearing A. Although not shown, the sensor units 51 may be provided at a plurality of locations, and the two sensor units 51 may share a contact fixing portion that is contact-fixed to the outer member.

  FIG. 12 shows a third embodiment of the present invention. In this embodiment, the speed reducer C is a planetary speed reducer. The electric motor B is a radial gap type as in the second embodiment. In the planetary reduction gear C, a sun gear 113 is integrally provided on the outer periphery of the input shaft 112, and a plurality of planetary gears 115 meshing with the sun gear 113 and the inner teeth 114 provided on the inner periphery of the outboard casing 33b of the reduction gear. Is rotatably supported by an inner pin 118 attached to the inboard side member 10 of the inner member 2. Also with this planetary reduction gear, the rotation of the output shaft 104 of the electric motor B can be decelerated and transmitted to the inner member 2 that is a hub. However, the reduction ratio is not as great as that of the cycloid reducer. Also in the third embodiment, the same sensor unit 51 is provided on the outer peripheral portion of the outer member 1 of the hub bearing A. As a result, it is possible to control the posture of the vehicle by measuring the force acting on the contact point between the wheel and the road surface.

  Also in the case of the third embodiment, as shown in FIG. 13, the sensor unit 51 may be provided on the outer periphery of the outer member 1 of the hub bearing A. Although not shown, the sensor units 51 may be provided at a plurality of locations, and the two sensor units 51 may share a contact fixing portion that is contact-fixed to the outer member.

In each of the above embodiments, the case where the component of the hub bearing A to which the sensor unit 51 is attached is the outer member 1, but the present invention is not limited to the other component of the hub bearing A, for example, the inner member. The present invention can also be applied to a wheel bearing device in which the sensor unit 51 is attached to 2.
Moreover, it is good also as a structure which connects directly the output shaft of an electric motor, and the hub of a wheel, without providing a reduction gear.
Further, in each of the above embodiments, the case where the hub bearing A is applied to a wheel bearing device of the third generation type has been described. However, in the present invention, the inner member of the hub bearing A and the wheel hub are independent from each other. The present invention can also be applied to a first or second generation type wheel bearing device. Further, the present invention can be applied to a wheel bearing device in which the hub bearing A is a tapered roller type of each generation type.

It is sectional drawing of the wheel bearing apparatus with a sensor with a built-in in-wheel type motor concerning 1st Embodiment of this invention. It is II-II sectional drawing of FIG. It is sectional drawing which expands and shows the principal part of FIG. It is a front view which shows the outward member and sensor unit of the wheel bearing apparatus with a sensor with a built-in in-wheel type motor. (A) is a top view of the sensor unit of the in-wheel type motor-equipped sensor-equipped wheel bearing device, and (B) is a side view thereof. It is a front view which shows the outward member and sensor unit of the in-wheel type motor-equipped sensor-equipped wheel bearing device which is another example of 1st Embodiment. It is a front view which shows the outward member and sensor unit of the bearing apparatus for wheels with a sensor with a built-in in-wheel motor which is another example of 1st Embodiment. It is sectional drawing of the wheel bearing apparatus with a sensor with a built-in in-wheel motor which is another example of 1st Embodiment. It is a front view which shows the outward member and sensor unit of the bearing apparatus for wheels with a sensor with a built-in in-wheel type motor. It is sectional drawing of the wheel bearing apparatus with an in-wheel type motor built-in sensor concerning 2nd Embodiment of this invention. It is sectional drawing of the wheel bearing apparatus with an in-wheel type motor built-in sensor which is another example of 2nd Embodiment. It is sectional drawing of the bearing apparatus for wheels with a sensor with a built-in in-wheel type motor concerning 3rd Embodiment of this invention. It is sectional drawing of the wheel bearing apparatus with an in-wheel type motor built-in sensor which is another example of 3rd Embodiment.

Explanation of symbols

1. Outer member (stationary raceway)
2 ... Inward member (hub)
DESCRIPTION OF SYMBOLS 5 ... Rolling body 51 ... Sensor unit 52 ... Sensor attachment member 52a ... 1st contact fixing | fixed part 52b ... 2nd contact fixing | fixed part 53 ... Strain sensor A ... Hub bearing B ... Electric motor C ... Reduction gear

Claims (6)

In the wheel bearing device in which the output shaft of the electric motor and the wheel hub of the vehicle are connected coaxially via a speed reducer or directly, and provided with a rolling bearing that supports the hub,
By detecting the distortion of the stationary-side bearing ring of the bearing, of the forces in the three axial directions in the vertical direction, the horizontal direction, and the front-rear direction orthogonal to each other at the ground contact point between the wheel attached to the hub and the road surface A sensor unit for measuring force in at least one direction;
The sensor unit is composed of a sensor mounting member and a strain sensor mounted on the sensor mounting member, and both ends of the sensor mounting member are mounted at two locations separated in the circumferential direction of the stationary side race. An in-wheel motor-equipped sensor-equipped wheel bearing device, characterized in that   2. The wheel bearing device according to claim 1, wherein the wheel bearing device includes an outer member having a double-row rolling surface formed on an inner periphery, and an inner surface having a rolling surface facing the rolling surface of the outer member. An in-wheel motor-equipped sensor-equipped wheel bearing device comprising a member and a double-row rolling element interposed between both rolling surfaces, wherein the outer member is a stationary raceway.   In Claim 1 and Claim 2, among the contact fixing portions of the sensor mounting member, the first contact fixing portion has three axes in the vertical direction, the horizontal direction, and the front-rear direction orthogonal to each other at the ground contact point of the wheel and the road surface. A sensor-equipped wheel bearing device with a built-in in-wheel motor, which is fixed at a location that is largely deformed in a radial direction as compared with other locations of the stationary raceway by a force in at least one of the directional forces.   4. The fixed portion of the second contact fixing portion of the contact fixing portions according to claim 3, wherein the fixing portion of the first contact fixing portion is the vertical direction and the right and left directions orthogonal to each other at the ground contact point of the wheel and the road surface. An in-wheel motor-equipped sensor-equipped bearing device in which the direction of radial distortion generated by the force in at least one of the direction and the force in the three axial directions in the front-rear direction is different.   5. The wheel bearing device with sensor according to claim 1, wherein the sensor unit includes a plurality of sensors.   6. The in-wheel motor-equipped sensor-equipped wheel according to claim 1, wherein the sensor unit is disposed at a position closer to an outboard side than a rolling surface on the outboard side of the stationary side fixed wheel. Bearing device.

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