JP5355042B2 - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing with a sensor capable of preventing a sensor from failing due to the influence of the external environment, accurately detecting the load acting on a bearing for a wheel or a tire surface in contact with ground for a long term, and facilitating cable wiring, and sensor installation. <P>SOLUTION: In the wheel bearing with the sensor, a rolling element 5 is interposed between double-row rolling surfaces 3, 4 of an outer member 1 and an internal member 2 so as face each other. An electronic part including a plurality of sensor units 20, a signal processing IC 25 for processing the sensor output signal, and a signal cable 26 for taking out the processed output signal out of the bearing is arranged inside of an annular protective cover 27 to make an annular sensor assembly 28. The sensor assembly 28 is concentrically fixed with a fixed-side member on the peripheral surface of the fixed-side member. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a sensor-equipped wheel bearing with a built-in load sensor for detecting a load applied to a bearing portion of the wheel.

  As a technology for detecting the load applied to each wheel of an automobile, a sensor-equipped wheel bearing has been proposed in which a strain sensor is provided on the outer diameter surface of the flange portion of the outer ring, which is a fixed ring of the wheel bearing, and the load is detected. (For example, Patent Document 1). In addition, as shown in FIG. 13, a wheel bearing is proposed in which a strain gauge 51 is attached to the outer ring 50 of the wheel bearing to detect the strain (for example, Patent Document 2).

  Further, a sensor unit comprising a strain generating member and a strain sensor attached to the strain generating member is attached to an inner diameter surface of an outer member that is a fixed ring of a bearing, and the strain generating member is at least 2 with respect to the outer member. There has been proposed a sensor-equipped wheel bearing having a contact fixing portion at one location, a notch portion at least at one location between adjacent contact fixing portions, and the strain sensor being disposed in the notch portion ( For example, Patent Document 3).

According to the sensor-equipped wheel bearing disclosed in Patent Document 3, when a load is applied to the rotating wheel as the vehicle travels, the fixed wheel is deformed via the rolling elements, and this deformation causes distortion of the sensor unit. The strain sensor provided in the sensor unit detects the strain of the sensor unit. If the relationship between strain and load is obtained in advance through experiments and simulations, the load applied to the wheel can be detected from the output of the strain sensor.
JP 2002-098138 A Special table 2003-530565 gazette JP 2007-57299 A

  However, the technique disclosed in Patent Document 1 in which a strain sensor is provided on the outer diameter surface of the outer ring flange portion of the wheel bearing, or Patent Document 2 in which a strain gauge 51 is attached to the outer ring 50 of the wheel bearing as shown in FIG. In the technology disclosed in the above, the sensor is not protected from the external environment. For this reason, there is a possibility that the pebbles jumped while the vehicle is running will hit the sensor and damage the sensor, or the sensor may be corroded by being covered with muddy water.

  In the technique disclosed in Patent Document 3, since the sensor unit is attached to the inner diameter surface of the outer ring of the wheel bearing, the sensor can be protected from the external environment, but the process of drawing the signal cable from the inside of the bearing to the outside of the bearing In addition, it is difficult to assemble the sensor unit.

  The object of the present invention is to prevent sensor failure due to the influence of the external environment, accurately detect the load acting on the wheel bearings and the tire ground contact surface over a long period of time, and facilitate signal cable wiring processing and sensor assembly. It is to provide a wheel bearing with a simple sensor.

The sensor-equipped wheel bearing according to the present invention includes an outer member having a double-row rolling surface formed on the inner periphery, an inner member having a rolling surface opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member a plurality of sensor units to the strain generating member is provided along the peripheral surface is fixed to come in contact with this peripheral surface, and attached to the strain generating member consists sensor for detecting the distortion of the strain generating member, An electronic sensor including a signal processing IC for processing the output signal of the sensor and a signal cable for taking out the processed output signal to the outside of the bearing is disposed inside the annular protective cover to form an annular sensor assembly. And this sensor assembly on the fixed side Only attached to the stationary member concentrically to the circumferential surface of the wood, the strain generating member has a notch on both sides of the central uniform width plane envelope is over its entire length, the sensor, the strain generating member The outer surface side is attached to a central portion between the notch portions on both sides, and an intermediate portion where the notch portion of the strain generating member is located is not in contact with the peripheral surface of the fixed side member, The sensor unit is provided at a position where each of the sensors has the same dimension with respect to the axial direction of the stationary member . The fixed side member is, for example, the outer member.

When a load acts between the wheel bearing or the tire of the wheel and the road surface, the load is also applied to the stationary side member (for example, the outer member) of the wheel bearing to cause deformation. Since the strain generating member in the sensor unit is fixed in contact with the fixed side member, the strain of the fixed side member is enlarged and transmitted to the strain generating member, the strain is detected with high sensitivity by the sensor, and the hysteresis generated in the output signal And the load can be estimated accurately.
In particular, an electronic component including a plurality of sensor units, a signal processing IC for processing an output signal of the sensor of the sensor unit, and a signal cable for taking out the processed output signal to the outside of the bearing is mounted on an annular protective cover. An annular sensor assembly is arranged on the inner side, and this sensor assembly is attached to the peripheral surface of the fixed side member concentrically with the fixed side member. It is possible to accurately detect the load acting on the wheel bearing and the tire ground contact surface over a long period of time by preventing the sensor failure due to the influence of the above. For example, electronic components such as sensors, signal processing ICs, and signal cables can be reliably protected from flying stones, muddy water, salt water, and the like from the outside. In addition, signal cable wiring processing and sensor assembly are facilitated.

In the present invention, the annular sensor assembly may be divided into two parts in the circumferential direction. For example, it is desirable that it can be divided into two at the center.
For example, when the sensor assembly is attached to the outer diameter surface of the fixed side member, the sensor assembly can be easily attached to the fixed side member by forming the sensor assembly in a two-part structure.

  In the present invention, the sensor unit may be bolted to the stationary member. In other words, the sensor unit is bolted so that the protective cover and the sensor unit can be fixed to the bearing at the same time. Since this fixing has a fixing structure that does not involve an interposed member such as a molding material, the sensor unit can be firmly fixed, and the fixing portion does not slip even when a load is applied, and the detection accuracy is improved.

In the present invention, it is preferable that an exposed portion of the electronic component from the protective cover in the sensor assembly attached to the fixed side member is sealed with a molding material. For example, the sensor assembly is sealed by being divided into two parts as described above, or after being fixed to the bearing by bolting or the like, and then filled with a molding material and secondarily molded. Instead of the molding material, a cylindrical protective cover may be bonded to the outer diameter surface of the sensor assembly after filling with an adhesive or a sealant.
In this configuration, the electronic parts such as the sensor unit, signal processing IC, and signal cable can be completely covered with the protective cover and the molding material, and these electronic parts are reliably prevented from being damaged by the external environment. it can.

In the present invention, the strain generating member may be as flat outline is made of a thin plate material in strip form of uniform width.
In the case of this configuration, the distortion of the fixed side member is easily transmitted to the distortion generating member, the distortion is detected with high sensitivity by the sensor, the hysteresis generated in the output signal is reduced, and the load can be estimated with high accuracy. Further, the shape of the strain generating member can be simplified, and it can be made compact and inexpensive.

In the present invention, it is desirable that the plurality of sensor units be provided at positions where each of the sensors has the same dimension with respect to the axial direction of the stationary member.
In the case of this configuration, since the sensor units are arranged at the same axial position in the fixed member, it is easy to cover all the sensor units with the protective cover, and the protective cover can be configured compactly.

  In the present invention, it is preferable that a cylindrical grinding surface is provided on the peripheral surface of the fixed side member, and a portion of the cylindrical grinding surface that is in contact with the strain generating member is a surface grinding surface portion. In particular, when the fixed-side member is the outer member, it is preferable that the entire outer periphery is a cylindrical grinding surface. In the case of this configuration, the sensor assembly can be easily attached to the fixed member, and the distortion generating material can be reliably contacted with the peripheral surface of the fixed member.

  In the present invention, the sensor assembly may be attached to the outer diameter surface of the stationary member. In this configuration, it is easy to attach the sensor assembly to the fixed member, and it is easy to protect the electronic parts such as the sensor unit, the signal processing IC, and the signal cable by the protective cover.

In the present invention, the plurality of sensor units may be arranged on an upper surface portion, a lower surface portion, a right surface portion, and a left surface portion of the outer diameter surface of the fixed side member that are in a vertical position and a horizontal position with respect to a tire ground contact surface. good. In this configuration, the load can be accurately estimated under any load condition. That is, when the load in a certain direction increases, the portion where the rolling element and the rolling surface are in contact with each other and the portion not in contact appear with a 180-degree phase difference. If installed, the load applied to the stationary member is always transmitted to any one of the sensor units via the rolling elements, and the load can be detected by the sensor.

The sensor-equipped wheel bearing according to the present invention includes an outer member having a double-row rolling surface formed on the inner periphery, an inner member having a rolling surface opposed to the rolling surface formed on the outer periphery, A wheel bearing comprising a double row rolling element interposed between opposing rolling surfaces of the member and rotatably supporting the wheel with respect to the vehicle body, wherein the fixed side member of the outer member and the inner member a plurality of sensor units to the strain generating member is provided along the peripheral surface is fixed to come in contact with this peripheral surface, and attached to the strain generating member consists sensor for detecting the distortion of the strain generating member, An electronic sensor including a signal processing IC for processing the output signal of the sensor and a signal cable for taking out the processed output signal to the outside of the bearing is disposed inside the annular protective cover to form an annular sensor assembly. And this sensor assembly on the fixed side Only attached to the stationary member concentrically to the circumferential surface of the wood, the strain generating member has a notch on both sides of the central uniform width plane envelope is over its entire length, the sensor, the strain generating member The outer surface side is attached to a central portion between the notch portions on both sides, and an intermediate portion where the notch portion of the strain generating member is located is not in contact with the peripheral surface of the fixed side member, The sensor unit is provided at a position where each of the sensors has the same dimension with respect to the axial direction of the fixed side member. The load acting on the sensor can be accurately detected over a long period of time, and signal cable wiring processing and sensor assembly are also facilitated. For example, electronic components such as sensors, signal processing ICs, and signal cables can be reliably protected from flying stones, muddy water, salt water, and the like from the outside.

  An embodiment of the present invention will be described with reference to FIGS. This embodiment is a third generation inner ring rotating type and is applied to a wheel bearing for driving wheel support. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  As shown in the sectional view of FIG. 1, the bearing for this sensor-equipped wheel bearing includes an outer member 1 in which a double row rolling surface 3 is formed on the inner periphery, and rolling facing each of these rolling surfaces 3. The inner member 2 has a surface 4 formed on the outer periphery, and the outer member 1 and the double row rolling elements 5 interposed between the rolling surfaces 3 and 4 of the inner member 2. This wheel bearing is a double-row angular ball bearing type, and the rolling elements 5 are made of balls and are held by a cage 6 for each row. The rolling surfaces 3 and 4 have an arc shape in cross section, and are formed so that the ball contact angle is aligned with the back surface. Both ends of the bearing space between the outer member 1 and the inner member 2 are sealed by a pair of seals 7 and 8, respectively.

The outer member 1 is a fixed side member, and has a vehicle body mounting flange 1a attached to a knuckle (not shown) in the suspension device of the vehicle body on the outer periphery, and the whole is an integral part. The vehicle body mounting flange 1a is provided with knuckle mounting screw holes 14 at a plurality of locations in the circumferential direction, and knuckle bolts (not shown) inserted into the knuckle bolt insertion holes from the inboard side are screwed into the screw holes 14. By doing so, the flange 1a is attached to a knuckle.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fit holes 16 for hub bolts 15 at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a braking component (not shown) protrudes toward the outboard side.

  Four sensor units 20 are provided on the outer diameter surface of the outer member 1 which is a fixed member. Here, these sensor units 20 are provided on the upper surface portion, the lower surface portion, the right surface portion, and the left surface portion of the outer diameter surface of the outer member 1 that is in the vertical position and the front-rear position with respect to the tire ground contact surface.

As shown in FIG. 8, these sensor units 20 include a strain generating member 21 and a strain sensor 22 that is attached to the strain generating member 21 and detects the strain of the strain generating member 21. The strain generating member 21 is made of an elastically deformable metal such as a steel material and is made of a thin plate material having a thickness of 2 mm or less. Further, the strain sensor 22 is affixed to a location where the strain increases with respect to the load in each direction on the strain generating member 21. Here, the central part sandwiched between the notch portions 21a on both sides is selected on the outer surface side of the strain generating member 21, and the strain sensor 22 detects the strain in the circumferential direction around the notch portion 21a. To do. Insertion holes 24 for bolts 23 (FIG. 2) for fixing the sensor unit 20 to the outer diameter surface of the outer member 1 are provided at two positions of the strain generating member 21 that are separated in the longitudinal direction across the strain sensor 22. It has been.
Note that the strain generating member 21 is plastically deformed even in a state in which an assumed maximum force is applied as an external force acting on the outer member 1 that is a fixed member or an acting force acting between the tire and the road surface. It is desirable not to do so. This is because when the plastic deformation occurs, the deformation of the outer member 1 is not transmitted to the sensor unit 20 and affects the measurement of strain.

The four sensor units 20 connect the signal processing ICs 25 for processing the output signals of the strain sensors 22 and the sensor units 20 and the signal processing ICs 25 to extract the processed output signals to the outside of the bearings. Along with electronic components such as the signal cable 26 (FIG. 8), they are arranged inside an annular protective cover 27 shown in front and side views in FIGS. 6 (A) and 6 (B). An annular sensor assembly 28 shown in a front view and a side view is formed in B). FIG. 8 is a development view of the electronic component disposed inside the protective cover 27. A signal cable 26 is wired between the sensor units 20 along the groove 29 of the protective cover 27, and a signal processing IC 25 is disposed in the middle of the signal cable 26. The signal cable 26 is attached so as to be wound around the bottom surface of the groove 29. A lead-out portion 26 a to the vehicle body side of the signal cable 26 is pulled out from one place of the protective cover 27 to the outside of the protective cover 27. The material of the protective cover 27 may be plastic or rubber, or may be made of metal.

  As shown in FIGS. 7A and 7B showing the sectional view taken along the arrows VIIa-VIIa and VIIb-VIIb in FIGS. Four locations serving as arrangement portions of the sensor units 20 in the direction are flat flat portions 27a across the width. A groove portion 29 extending in the circumferential direction is provided on the outer diameter surface of the protective cover 27, and a rectangular opening that penetrates from the groove portion 29 to the inner diameter surface in the radial direction is provided at each of the flat portions 27a. 30 are provided. Engagement step portions 30 a with which the strain generating members 21 of the sensor unit 20 are engaged are provided on both side edges along the circumferential direction on the inner diameter side of these openings 30. Each engagement step 30a is provided on the flat portion 27a. Accordingly, as shown in FIGS. 10A and 10B showing the Xa-Xa arrow cross-sectional view and the Xb-Xb arrow cross-sectional view of FIGS. 9A and 9B, the opening 30 of the protective cover 27. Further, each sensor unit 20 is attached to each flat portion 27a with its strain generating member 21 exposed to the inner diameter side. As described above, each sensor unit 20 is attached with the strain generating member 21 exposed on the inner diameter surface of the protective cover 27, so that the strain generating member 21 is brought into close contact with the outer diameter surface of the outer member 1 that is a fixed member. The elastic deformation of the outer member 1 can be effectively transmitted to the strain generating member 21. The opening 30 is an opening that allows the sensor unit 20 to be wired and bolted from the outer peripheral side of the protective cover 27.

  The annular sensor assembly 28 can be divided into two at the center as shown in FIGS. Specifically, an annular protective cover 27 is formed by connecting one end of each of the two divided bodies 27 </ b> A and 27 </ b> B with a hinge 31 so that the two half arcs of the sensor assembly 28 can be opened via the hinge 31. The part can be opened and closed. The maximum value of the opening dimension W in the open state of the sensor assembly 28 is set to be larger than the outer diameter dimension D (FIG. 4) of the outer member 1. As a result, the sensor assembly 28 can be attached to the outer diameter surface of the outer member 1 by opening the sensor assembly 28 in a state where the opening dimension W is maximized.

  FIG. 4 shows a partially broken front view of the outer member 1 viewed from the outboard side. The vehicle body mounting flange 1a of the outer member 1 is a projecting piece 1aa in which a circumferential portion provided with each screw 14 protrudes to the outer diameter side from the other portion. A cylindrical ground surface 1b is provided at the axial position of the outer diameter surface of the outer member 1 where the sensor assembly 28 is attached. In addition, four portions of the cylindrical grinding surface 1b with which the strain generating member 21 of the sensor unit 20 comes into contact, that is, an upper surface portion, a lower surface portion, a right surface portion, and a left surface portion are the same as the surface grinding surface portion 1c as shown in FIG. Has been. Thereby, the distortion generating member 21 of each sensor unit 20 can be reliably brought into contact with the surface grinding surface portion 1c. Further, each surface grinding surface portion 1c is provided with a screw hole 32 that matches the bolt insertion hole 24 of the strain generating member 21. Thus, after the sensor assembly 28 is assembled to the cylindrical grinding surface 1b, the bolt 23 inserted into the bolt insertion hole 24 of the strain generating member 21 is screwed into the screw hole 32, so that the sensor unit 20 is externally attached. At the same time, the entire sensor assembly 28 is also fixed. An intermediate portion sandwiched between the two screw holes 32 in the surface grinding surface portion 1c is provided with a groove 1d extending in the axial direction. Thereby, since the intermediate site | part in which the notch part 21a in the distortion generation member 21 is located is separated from the surface grinding surface part 1c, distortion deformation of the periphery of the notch part 21a becomes easy. The four sensor units 20 are provided at positions where the respective strain sensors 22 have the same dimensions with respect to the axial direction of the outer member 1.

  FIG. 3 is an enlarged view of the mounting portion of the sensor assembly 28 of the outer member 1 in FIG. As shown in the figure, after the sensor assembly 28 is attached to the outer diameter surface of the outer member 1, a protective cover 27 for the electronic components (sensor unit 20, signal processing IC 25, signal cable 26) in the sensor assembly 28 is obtained. The exposed portion is sealed with a molding material 33. That is, secondary molding is performed by the molding material 33. Specifically, the groove 29 of the protective cover 27 is filled with the molding material 33 over the entire periphery, and the exposed portion of the electronic component is sealed.

  Instead of using the molding material 33 to seal the exposed portion of the electronic component, the groove 29 of the protective cover 27 is filled with an adhesive or a sealing agent, and then the outer diameter surface of the sensor assembly 28 is filled. A ring-shaped outer cover 34 composed of two semicircular divided bodies 34A and 34B as shown in FIGS. 12A and 12B may be bonded and fixed as shown by phantom lines in FIG. That is, after attaching the sensor assembly 28 to the bearing, the ring-shaped outer cover 34 may be attached to the outer diameter surface of the sensor assembly 28.

  Various strain sensors 22 can be used. For example, the strain sensor 22 can be composed of a metal foil strain gauge. In that case, the distortion generating member 21 is usually fixed by adhesion. The strain sensor 22 can also be formed on the strain generating member 21 with a thick film resistor.

  The strain sensor 22 of the sensor unit 20 is connected to the signal processing IC 25. The signal processing IC 25 receives the force (vertical load Fz, load Fx serving as a driving force or braking force, axial load) acting on the wheel bearing or between the wheel and the road surface (tire contact surface) according to the output signal of the strain sensor 22. Fy) is estimated and includes a signal processing circuit and a correction circuit. The signal processing IC 25 has relationship setting means (not shown) in which the relationship between the acting force and the output signal of the strain sensor 22 is set by an arithmetic expression or a table, and the relationship setting is performed from the input output signal. The value of the acting force is output using the means. The setting contents of the relationship setting means are obtained by a test or simulation in advance.

When a load acts between the tire of the wheel and the road surface, the load is also applied to the outer member 1 that is a stationary member of the wheel bearing, causing deformation. Since the strain generating member 21 in the sensor unit 20 is fixed in contact with the peripheral surface of the outer member 1, the strain of the outer member 1 is enlarged and transmitted to the strain generating member 21, and the strain is transmitted to the strain sensor 22. And the hysteresis generated in the output signal is reduced, and the load can be estimated with high accuracy. In particular, a plurality of sensor units 20, a signal processing IC 25 that processes output signals of the strain sensors 22, and a signal that connects the sensor units 20 and the signal processing IC 25 to extract the processed output signals to the outside of the bearing. An electronic component including the cable 26 is arranged inside an annular protective cover 27 to form an annular sensor assembly 28, and the sensor assembly 28 is concentric with the outer member 1 on the outer surface of the outer member 1. Therefore, it is possible to prevent the electronic components including the sensor unit 20 from being damaged due to the external environment (damage due to stepping stones, corrosion due to muddy water, salt water, etc.), and the load can be accurately detected over a long period of time. In addition, wiring processing of the signal cable 26 and assembly of the strain sensor 22 are facilitated.

In the above description, the case where the acting force between the wheel tire and the road surface is detected is shown. However, not only the acting force between the wheel tire and the road surface but also the force acting on the wheel bearing (for example, the preload amount) is detected. But it ’s okay.
By using the detected load obtained from the sensor-equipped wheel bearing for vehicle control, it is possible to contribute to stable running of the automobile. In addition, when this sensor-equipped wheel bearing is used, a load sensor can be installed in a compact vehicle, the mass productivity can be improved, and the cost can be reduced.

  In this embodiment, since the sensor assembly 28 can be divided into two at the center, it is easy to attach the outer member 1 which is a fixed member to the peripheral surface, and the assemblability is improved.

  Further, in this embodiment, the strain generating member 21 of the sensor unit 20 is fixed directly to the peripheral surface of the outer member 1 which is a fixed member with the bolts 23, so that fixing is performed without interposing a molding material or the like. The sensor unit 20 can be firmly fixed. In addition, even when a load is applied, it is possible to prevent slippage between the sensor unit 20 and the outer member 1 that is a fixed member, and the detection accuracy can be improved accordingly. In addition, by fixing the sensor unit 20 to the outer member 1 with the bolts 23, the sensor assembly 28 can be attached to the outer member 1 at the same time, so that the assemblability is further improved. Since the through hole 30 is provided in the protective cover 27, the sensor assembly 28 is attached to the outer member 1, and then the outer side of the sensor assembly 28 with the strain generating member 21 and the bolt 23 in direct contact with each other. It can be fixed to the member 1.

  If the dimension of the axial position of the sensor unit 20 fixed to the outer diameter surface of the outer member 1 which is a fixed side member is different, the strain transmitted from the outer diameter surface of the outer member 1 to the strain generating member 21 is also different. . In this embodiment, the sensor units 20 are provided at positions where the respective strain sensors 22 have the same dimensions with respect to the axial direction of the outer member 1, so that a plurality of protective units 27 are provided around the axial position. The electronic parts including the sensor unit 20 can be protected, and the protective cover 27 can be made compact.

  Further, in this embodiment, the sensor assembly 28 is attached to the outer diameter surface of the outer member 1 that is a fixed member, and the outer peripheral surface of the outer member 1 is provided with a cylindrical grinding surface 1b over the entire circumference. Since the portion of the cylindrical grinding surface 1b that contacts the strain generating member 21 of the sensor unit 20 is the surface grinding surface portion 1c, the sensor assembly 28 can be easily attached to the outer member 1, and the outer member 1 The contact of the strain generating material 21 on the outer diameter surface is ensured.

  Moreover, in this embodiment, since the distortion generating member 21 of the sensor unit 20 is made of a thin plate material having a belt-like general shape as shown in FIG. The distortion 1 is easily transmitted to the distortion generating member 21, and the distortion is detected with high sensitivity by the distortion sensor 22. Hysteresis generated in the output signal is also reduced, and the load can be estimated with high accuracy. Further, the shape of the strain generating member 21 is also simple, and it can be made compact and low cost. The same applies to the case where the strain generating member 21 is a belt having a uniform planar shape.

In this embodiment, since the sensor unit 20 is provided on the upper surface portion and the lower surface portion, and the right surface portion and the left surface portion of the outer diameter surface of the outer member 1 that is a fixed side member, under any load condition. The load can be estimated with high accuracy. That is, when the load in a certain direction increases, a portion where the rolling element 5 and the rolling contact surface 3 are in contact with each other and a portion which is not in contact appear with a 180-degree phase difference. If it is installed with a phase difference, the load applied to the outer member 1 is always transmitted to any one of the sensor units 20 via the rolling elements 5, and the load can be detected by the strain sensor 22.
In this case, the upper surface portion and the lower surface portion on which the sensor unit 20 is provided on the outer diameter surface of the outer member 1 are intermediate positions of the interval B between the left and right protruding pieces 1aa in the vehicle body mounting flange 1a as shown in FIG. Is desirable. Further, the right surface portion and the left surface portion where the sensor unit 20 is provided on the outer diameter surface of the outer member 1 are also located at an intermediate position of the interval A between the vertically adjacent projecting pieces 1aa in the vehicle body mounting flange 1a as shown in FIG. It is desirable to do. As described above, when the fixed position of the sensor unit 20 is set, the influence of the side slip centering on the knuckle bolt that causes the hysteresis can be reduced, the hysteresis generated in the output signal of the strain sensor 22 is reduced accordingly, and the load is more accurate. Can be estimated well.

  In each of the above embodiments, the case where the outer member 1 is a fixed side member has been described. However, the present invention can also be applied to a wheel bearing in which the inner member is a fixed side member. The assembly 28 is provided on the peripheral surface that is the inner periphery of the inner member.

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

It is sectional drawing of the bearing for wheels with a sensor concerning one Embodiment of this invention. It is II-II arrow sectional drawing in FIG. It is an expanded sectional view of the sensor assembly installation part in the outward member of FIG. It is a front view which fractures | ruptures and shows a part which looked at the outward member from the outboard side. It is a side view of the outward member. (A) is a front view of an annular | circular shaped protective cover, (B) is the side view. (A) is a sectional view taken along the arrow VIIb-VIIb in FIG. 6 (B), and (B) is a sectional view taken along the arrow VIIa-VIIa in FIG. 6 (A). It is an expanded view of the electronic component installed in a sensor assembly. (A) is a front view of the sensor assembly, and (B) is a side view of the sensor assembly. (A) is Xb-Xb arrow sectional drawing in FIG. 9 (B), (B) is Xa-Xa arrow sectional drawing in FIG. 9 (A). (A) is a front view which shows the closed state of a sensor assembly, (B) is a front view which shows the open state of the sensor assembly. (A) is a side view of a split body of the ring-shaped outer cover, and (B) is a front view of the ring-shaped outer cover. It is a perspective view of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit 21 ... Strain generating member 21a ... Notch part 22 ... Strain sensor 23 ... Bolt 25 ... Signal processing IC
26 ... Signal cable 27 ... Protective cover 28 ... Sensor assembly 33 ... Mold material

Claims (9)

An outer member having a double row rolling surface formed on the inner periphery, an inner member having a rolling surface facing the rolling surface formed on the outer periphery, and interposed between the opposing rolling surfaces of both members A double row rolling element, and a wheel bearing for rotatably supporting the wheel with respect to the vehicle body,
The outer member and the inner strain generating member fixed to come in contact with this circumferential surface is provided along the peripheral surface of the stationary member of the member, and attached to the strain generating member the strain generating member An electronic component including a plurality of sensor units composed of sensors for detecting distortion of the sensor, a signal processing IC for processing the output signal of the sensor, and a signal cable for extracting the processed output signal to the outside of the bearing the annular sensor assembly disposed in the inside of the protective cover, only mounting the sensor assembly to the stationary member concentrically to the circumferential surface of the stationary member, the strain generating member is a plan outline overall length Having a notch on both sides of the center with a uniform width, and attaching the sensor to a central portion between the notches on both sides on the outer surface side of the strain generating member. Cut off The intermediate portion where the groove portion is located is not in contact with the peripheral surface of the fixed side member, and the plurality of sensor units are provided at positions where the respective sensors have the same dimensions with respect to the axial direction of the fixed side member. A sensor-equipped wheel bearing characterized by the above.   The sensor-equipped wheel bearing according to claim 1, wherein the fixed-side member is the outer member.   The sensor-equipped wheel bearing according to claim 1 or 2, wherein the annular sensor assembly can be divided into two divided bodies in a circumferential direction.   4. The sensor-equipped wheel bearing according to claim 1, wherein the sensor unit is bolted to the stationary member.   5. The wheel bearing with sensor according to claim 1, wherein an exposed portion of the electronic component from the protective cover in the sensor assembly attached to the fixed side member is sealed with a molding material. In any one of claims 1 to 5, wherein the strain generating member, bearing with sensor wheel plane envelope is made of a thin plate material in strip form of uniform width. In any one of claims 1 to 6, the cylindrical grinding surface provided over the whole circumference on the peripheral surface of the stationary member, and the surface grinding face a portion where the strain generating member contacts of the cylindrical grinding surface Bearing for sensor wheel. The sensor-equipped wheel bearing according to any one of claims 1 to 7 , wherein the sensor assembly is attached to an outer diameter surface of the fixed side member. 9. The sensor according to claim 8 , wherein the plurality of sensor units are arranged on an upper surface portion, a lower surface portion, a right surface portion, and a left surface portion of the outer diameter surface of the fixed side member that are in a vertical position and a horizontal position with respect to a tire ground contact surface. Wheel bearing.

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