JP5355118B2 - Wheel bearing with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor-equipped bearing for a wheel capable of preventing failure of the sensor caused by effect of the external environment, accurately detecting load acting on the bearing for wheel or a tire tread over a long period of time, and facilitating wiring processing of a signal cable and assembly of the sensor. <P>SOLUTION: This sensor-equipped bearing for wheel includes a rolling element 5 interposed between double row rolling faces 3, 4 of an external member 1 and an internal member 2. A sensor assembly 28 having electronic components including a plurality of load detecting sensor units 20, a signal processing unit 26 for processing output signals of the sensor units 20, and the signal cable 27 for taking out the output signals to the outside of the bearing connected in a ring-shape, is concentrically mounted on an outer peripheral face of a fixed side member out of the external member 1 and the internal member 2. The sensor assembly 28 is covered by a cylindrical protective cover 29 with its inner diameter increased toward an inboard side. An inboard side end is suitable for the outer peripheral face of the fixed side member, and an outboard side end is mounted on the outer peripheral face of the fixed side member via an O-ring 30. <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). Further, as shown in FIG. 14, 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 and the like 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 salt 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, and a rolling element of double rows interposed between rolling surfaces of opposed members, at the wheel support bearing assembly for rotatably supporting a wheel relative to a vehicle body, a load detection is fixed to the outer peripheral surface of the outer member A sensor comprising a plurality of sensor units, a signal processing IC for processing an output signal of the sensor unit, and a signal cable for taking out the processed output signal to the outside of the bearing, connected in a ring shape the assembly, with attached to the outer member concentric to the outer circumferential surface of the outer member, covered with a cylindrical protective cover inner diameter toward the sensor assembly on the inboard side is enlarged, in the protective cover the board-side end to the outer peripheral surface of the outer member Engaged, mount the outboard side end of the protective cover on the outer peripheral surface of the outer member through the seal ring of the elastic body only, the sensor unit, the outer peripheral surface provided along the outer peripheral surface of the outer member A strain generating member that is fixed in contact with the strain generating member, and a strain sensor that is attached to the strain generating member and detects the strain of the strain generating member. And having a notch on both sides of the center, and attaching the strain sensor to a central portion between the notches on both sides on the outer surface side of the strain generating member. The intermediate portion where the notch is located is not in contact with the outer peripheral surface of the outer member .
According to the configuration of this, a plurality of sensor units for load detection, the IC signal processing, the sensor assembly formed by connecting in a ring shape an electronic component and a signal cable for taking out of the output signal, the outer peripheral surface of the outer member is a stationary member with attached to the outer member concentric, is covered with a cylindrical protective cover to increase the inner diameter toward the sensor assembly on the inboard side. The inboard side end of this protective cover is fitted to the outer peripheral surface of the outer member , and the outboard side end of the protective cover is attached to the outer peripheral surface of the outer member via a seal ring, thus protecting the sensor assembly. It can be covered with a cover to prevent sensor failure due to the influence of the external environment and accurately detect the load acting on the wheel bearing and the tire ground contact surface over a long period of time. For example, electronic components such as sensor units, signal processing ICs, signal cables, and the like 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 unit assembly are facilitated.
Because before Symbol protective cover is attached to the outer peripheral surface of the outer member, and easily attach the protective cover, it is easy to perform protection of the sensor assembly by the protective cover.

  In the present invention, the protective cover is desirably a stepped cylindrical shape having a large diameter on the inboard side. Thus, when the protective cover has a stepped cylindrical shape with a large diameter on the inboard side, the protective cover can be easily press-fitted from the outboard side of the fixed side member to the outer peripheral surface of the fixed side member.

  In this invention, the material of the protective cover may be a metal material or a resin material. If it is a metal material, the protective cover can be firmly attached to the outer peripheral surface of the stationary member firmly and with good sealing performance. Further, when the resin material is used, the protective cover can be easily molded, and can be attached to the outer peripheral surface of the stationary member with good sealing performance. Thereby, the failure of the sensor due to the influence of the external environment can be prevented more reliably.

In this invention, the whole of the protective cover may be made of a resin material, and a metal material may be embedded in a fitting portion of the inboard side end to the outer peripheral surface of the outer member . In this configuration, the fitting to the outer peripheral surface of the outer member of the in-boat end of the protective cover can be performed firmly and sealed with good and it is easy molding of the protective cover.

In the present invention, a groove extending in the circumferential direction may be provided on the outboard side of the outer peripheral surface of the outer member , and the seal ring may be fitted into the groove. In this configuration, the seal ring can be positioned stably well to the outer peripheral surface of the outer member, it is securely sealed between the outer peripheral surface of the outboard-side end and the outer member of the protective cover.

According to the present invention, an inward flange is formed on an outboard side end of the protective cover, and a ridge that extends in the circumferential direction on the outer peripheral surface of the outer member and faces the inward flange of the protective cover in the axial direction. The seal ring may be sandwiched between the protrusion and the inward flange of the protective cover. In this configuration, the seal ring is positioned in the axial direction by being sandwiched between the inward flange of the protective cover and the protrusion extending in the circumferential direction of the outer peripheral surface of the outer member , and the outboard side end of the protective cover The space between the outer peripheral surface of the outer member is securely sealed.

  In the present invention, the seal ring is preferably made of a rubber material such as nitrile rubber or silicon rubber. In this case, the sealing performance by the seal ring can be ensured.

In this invention, the signal cable lead-out portion from the protective cover is provided at a part of at least one of the outer peripheral surface of the outer member and the fitting portion of the protective cover to be fitted to each other. It is desirable to provide a cutout portion from which the signal cable is drawn, and to fill the portion where the signal cable leadout portion is drawn out from the cutout portion with a sealing material. In the case of this configuration, the signal cable lead-out portion is sandwiched between the notches to be positioned in the circumferential direction, and the sealing performance of the protective cover can be further improved.

In this invention, the sensor unit and the signal processing IC in the sensor assembly may be fixed to the outer peripheral surface of the outer member in the protective cover. In the case of this configuration, it is possible to prevent the fixing portion of the sensor unit and the signal processing IC from being corroded by the external environment and becoming unstable.

  In this invention, the inside of the protective cover may be filled with an elastic filler. In the case of this configuration, the electronic parts such as the sensor unit, the signal processing IC, and the signal cable can be surely protected from the stepping stones, muddy water, salt water and the like due to the elastic filler to be filled.

In this invention, the outer peripheral surface of the outer member may be subjected to rust prevention treatment. In this configuration, the outer peripheral surface of the outer member can be prevented from being rusted by muddy water, salt water, etc., so that the outer surface of the outer member can be reliably prevented from reaching the sensor assembly covered with the protective cover. it can.

In the present invention, the sensor unit, before and Kiibitsu seen generating member has one or more strain sensors for detecting strain of the attached to the strain onset producing member in the strain generating member, from the output signal of the strain sensor The deformation of the outer member may be detected to detect the load applied to the wheel bearing.
And wheel bearing, the load between the wheels of the tire and the road surface acting, deformation load to the outer member is fixed side member of the wheel bearing is applied. Since the strain generating member in the sensor unit is fixed in contact with the outer member, the strain of the outer member is transmitted to expand the strain generating member, the strain is detected sensitively by the sensor, can be accurately estimated load .

In this invention, the strain generating member has two or more contact fixing portions fixed in contact with the outer peripheral surface of the outer member , and these contact fixing portions are arranged with respect to the axial direction of the outer member . You may provide in the position used as the same dimension.
When the axial dimension of each contact fixing portion of the strain generating member of the sensor unit fixed to the outer member is different, the strain transmitted from the outer member to the strain generating member via the contact fixing portion is also different. If the contact fixing portions of the strain generating member of the sensor unit are provided so as to have the same dimension in the axial direction as described above, the strain tends to concentrate on the strain generating member, and the detection sensitivity is improved accordingly. In addition, since the sensor units are arranged in the same axial direction position on the outer member , all the sensor units can be covered only by providing a protective cover at the axial position, and the protective cover can be made compact. Can do.

In the present invention, the strain generating member may be as flat outline is made of a thin plate material in strip. In the case of this configuration, the distortion of the outer member is easily transmitted to the distortion generating member, the distortion is detected with high sensitivity by the sensor, 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, the strain generating member may not be plastically deformed even in a state in which a maximum force assumed as an external force acting on the outer member or an acting force acting between the tire and the road surface is applied. good. If plastic deformation occurs before the assumed maximum force is applied, the deformation of the outer member will not be transmitted accurately to the sensor unit and will affect the strain measurement. It is desirable that plastic deformation does not occur even in a state where is applied. The "maximum force expected" is the maximum force within the range where normal function as a bearing excluding the sensor system can be restored even if an abnormally large force is applied to the bearing. is there.

In this invention, you may arrange | position the said sensor unit in the upper surface part of the outer peripheral surface of the said outer member used as an up-down position and a left-right position with respect to a tire ground-contact surface, a lower surface part, a right surface part, and a left surface part. 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 outer member is always transmitted to one of the sensor units via the rolling elements, and the load can be detected by the sensor.

The method for assembling the sensor-equipped wheel bearing according to the present invention is the method for assembling the sensor-equipped wheel bearing according to the present invention, wherein the outer member is a single member or the rolling member is assembled to the outer member. , attaching the sensor assembly and the seal ring on an outer peripheral surface of the outer member, after press-fitting the protective cover to the outer peripheral surface of the outer member, characterized in that assembling the bearing.
According to this assembling method, the sensor-equipped wheel bearing in which the sensor assembly attached to the outer member is covered with the protective cover can be easily assembled.

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, and a rolling element of double rows interposed between rolling surfaces of opposed members, at the wheel support bearing assembly for rotatably supporting a wheel relative to a vehicle body, a load detection is fixed to the outer peripheral surface of the outer member A sensor comprising a plurality of sensor units, a signal processing IC for processing an output signal of the sensor unit, and a signal cable for taking out the processed output signal to the outside of the bearing, connected in a ring shape the assembly, with attached to the outer member concentric to the outer circumferential surface of the outer member, covered with a cylindrical protective cover inner diameter toward the sensor assembly on the inboard side is enlarged, in the protective cover the board-side end to the outer peripheral surface of the outer member Engaged, mount the outboard side end of the protective cover on the outer peripheral surface of the outer member through the seal ring of the elastic body only, the sensor unit, the outer peripheral surface provided along the outer peripheral surface of the outer member A strain generating member that is fixed in contact with the strain generating member, and a strain sensor that is attached to the strain generating member and detects the strain of the strain generating member. And having a notch on both sides of the center, and attaching the strain sensor to a central portion between the notches on both sides on the outer surface side of the strain generating member. Since the intermediate part where the notch is located is not in contact with the outer peripheral surface of the outer member, the sensor failure due to the influence of the external environment is prevented, and the load acting on the wheel bearing and the tire ground contact surface is extended over a long period of time. Accurate inspection Can, the easy assembling of the wiring process and sensor signal cables.
The assembly method for the sensor-equipped wheel bearing according to the present invention is an assembly method for assembling the sensor-equipped wheel bearing according to the present invention, wherein the outer member is in a single state or the rolling element is assembled to the outer member. in attaching a seal ring of the sensor assembly and an elastic body on the outer peripheral surface of the outer member, after press-fitting the protective cover to the outer peripheral surface of the outer member, since the assembling of the bearing, fitted to the outer member The sensor-equipped wheel bearing in which the sensor assembly is covered with a protective cover can be easily assembled.

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 a front view of the wheel bearing with the sensor. It is a front view which shows the state which removed the protective cover of the bearing for wheels with a sensor. (A) is sectional drawing which looked at the outward member in the wheel bearing with a sensor from the outboard side, (B) is the partial front view which looked at the E section in (A) from the direction of arrow P. (A) is a front view of a protective cover in the wheel bearing with sensor, and (B) is a side view thereof. (A) is a top view of the drawer | drawing-out part of the signal cable in the wheel bearing with a sensor, (B) is the side surface sectional drawing. It is an expanded sectional view of the D section in FIG. It is a top view of the sensor unit installation part of the outward member in the wheel bearing with a sensor. It is a top view which shows the state before sensor unit attachment of the sensor unit installation part of the outward member in FIG. It is the front view which looked at the outward member from the outboard side. It is sectional drawing of the bearing for wheels with a sensor concerning other embodiment of this invention. It is sectional drawing of the bearing for wheels with a sensor concerning further another embodiment of this invention. It is a perspective view of a prior art example.

  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 flange 1a is a projecting piece 1aa (FIG. 5) in which a circumferential portion provided with each screw hole 14 protrudes to the outer diameter side from other portions.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The hub flange 9a is provided with press-fitting holes 16 for hub bolts (not shown) at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a wheel and a 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.

  These sensor units 20 include a strain generating member 21 and a strain generating member 21 attached to the strain generating member 21 as shown in the plan views of FIGS. And a distortion sensor 22 for detecting the distortion of the above. 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. In addition, the strain generating member 21 has two contact fixing portions 21 a at both ends that are fixed in contact with the outer diameter surface of the outer member 1. Note that, depending on the shape of the strain generating member 21, two or more contact fixing portions 21a may be provided. 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, as the location, a central portion sandwiched between the notch portions 21b on both sides is selected on the outer surface side of the strain generating member 21, and the strain sensor 22 measures the circumferential strain around the notch portion 21b. To detect. 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 "maximum force expected" is the maximum force within the range where normal function as a bearing excluding the sensor system can be restored even if an abnormally large force is applied to the bearing. is there.

  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.

  In the sensor unit 20, the two contact fixing portions 21a of the strain generating member 21 are located at the same dimension in the axial direction of the outer member 1, and the two contact fixing portions 21a are separated from each other in the circumferential direction. These contact fixing portions 21 a are fixed to the outer diameter surface of the outer member 1 by bolts 23. In order to stably fix the sensor unit 20 to the outer diameter surface of the outer member 1, a flat portion 1 b is formed at a place where the contact fixing portion 21 a on the outer diameter surface of the outer member 1 is contact-fixed. Further, a groove 1c is provided at two intermediate portions where the two contact fixing portions 21a are fixed on the outer diameter surface of the outer member 1. Each of the bolts 23 is inserted through a bolt insertion hole 24 provided in the contact fixing portion 21a in the radial direction, and is screwed into a screw hole 25 provided in the outer diameter surface of the outer member 1. As described above, the two contact fixing portions 21a of the strain generating member 21 are fixed to the outer diameter surface of the outer member 1 with the groove 1c interposed therebetween, thereby having a cutout portion 21b in the strain generating member 21 which is a thin plate shape. The central part is in a state of being separated from the outer diameter surface of the outer member 1, and distortion deformation around the notch 21b is facilitated.

  As shown in FIG. 4, the four sensor units 20 include a signal processing unit 26 that processes output signals of these strain sensors 22, and a signal cable 27 that extracts the processed output signals to the outside of the bearing. A sensor assembly 28 is connected to the electronic component in a ring shape, and the sensor assembly 28 in the ring shape is attached to the outer diameter surface of the outer member 1 concentrically with the outer member 1. The signal cable 27 is wired between the sensor units 20, and the signal processing unit 26 is disposed in the middle of the signal cable 27 and is fixed to the outer diameter surface of the outer member 1. In this case, the four sensor units 20 are disposed at the same axial position on the outer diameter surface of the outer member 1 as shown in FIG. 2 showing a cross-sectional view taken along the line II-II in FIG.

  The signal processing unit 26 uses the output signal of the strain sensor 22 to generate a force (vertical load Fz, driving force Fx, axial load Fy) acting between the wheel bearing and the wheel and the road surface (tire contact surface). The signal processing IC and a circuit board on which the IC is mounted are included. The signal processing IC includes a signal processing circuit and a correction circuit for processing a distortion signal. The signal processing IC of the signal processing unit 26 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 or the like. The value of the acting force is output from the output signal using the relationship setting means. The setting contents of the relationship setting means are obtained by a test or simulation in advance.

The sensor assembly 28 attached to the outer diameter surface of the outer member 1 is covered with a protective cover 29 as shown in FIG. The protective cover 29 has a cylindrical shape whose inner diameter increases toward the inboard side. Specifically, the protective cover 29 has a stepped cylindrical shape in which the inboard side half is the large diameter portion 29a and the outboard side half is the small diameter portion 29b. The inboard side end of the protective cover 29 is fitted to the outer diameter surface of the outer member 1, and the outboard side end of the protective cover 29 is an O-ring 30 which is an elastic seal ring concentric with the outer member 1. It is attached to the outer diameter surface of the outer member 1 via The small-diameter portion 29b of the protective cover 29 has a tapered shape that decreases in diameter toward the outboard side so as to follow the outer-diameter surface of the outer member 1 via a gap. The large-diameter portion 29 a forms an accommodation space for accommodating the sensor unit 20 between the inner peripheral surface thereof and the outer peripheral surface of the outer member 1. As the material of the protective cover 29, a metal material such as stainless steel or a resin material such as PA66 + GF is used. As shown in FIG. 4, a groove 1d for fitting an O-ring that extends in the circumferential direction is provided on the outboard side of the outer diameter surface of the outer member 1, and an O-ring 30 is fitted into the groove 1d as shown in FIG. By attaching, the O-ring 30 is positioned in the axial direction, and the space between the outboard side end of the protective cover 29 and the outer diameter surface of the outer member 1 is securely sealed. The O-ring 30 is made of a rubber material such as nitrile rubber or silicon rubber . Thereby, the sealing performance by the O-ring 30 can be ensured.

  Further, the sensor unit 20 and the signal processing unit 26 in the sensor assembly 28 are fixed to the outer diameter surface of the outer member 1 in the protective cover 29. It can prevent the fixing from becoming unstable due to corrosion. The internal space of the protective cover 29 may be filled with an elastic filler such as mold resin or urethane foam. In this case, the electronic parts such as the sensor unit 20, the signal processing unit 26, and the signal cable 27 can be surely protected from the stepping stones, muddy water, salt water, and the like due to the elastic filler to be filled. it can.

  Further, the entire outer diameter surface of the outer member 1 may be subjected to rust prevention treatment. In this case, since the outer diameter surface of the outer member 1 can be prevented from being rusted by muddy water, salt water, etc., the rust on the outer diameter surface of the outer member 1 reaches the sensor assembly 28 covered with the protective cover 29. Can be reliably prevented.

  As shown in FIG. 3, the lead-out portion 27 a of the signal assembly 27 in the sensor assembly 28 toward the vehicle body is pulled out from one place of the protective cover 29. Specifically, as shown in parts E and F in FIGS. 5A and 5B and part G in FIG. 6B, the step toward the outboard side of the outer diameter surface of the outer member 1. Cutout portions 32 and 33 into which the signal cable lead-out portion 27a is inserted are provided at one location in the circumferential direction of the surface portion and one location in the circumferential direction at the inboard side end of the protective cover 29 facing the surface portion.

  The notch in this case may be provided only on the outer diameter surface of the outer member 1 as shown in FIGS. 7A and 7B, or may be provided only on the protective cover 29. As a result, as shown in FIGS. 7A and 7B, the signal cable lead-out portion 27a is sandwiched between the cutout portions 32 and 33 and positioned in the circumferential direction. A portion where the signal cable lead-out portion 27a is pulled out from the notches 32 and 33 may be filled with a sealing material to seal the lead-out portion of the signal cable lead-out portion 27a. Thereby, the sealing performance of the protective cover 29 can be further enhanced.

  The assembly of the sensor-equipped wheel bearing is performed according to the following procedure. First, in a state where the outer member 1 is a single body or a state where the rolling element 5 is assembled to the outer member 1, the ring-shaped sensor assembly 28 is attached to the outer diameter surface of the outer member 1 as shown in FIG. The O-ring 30 is fitted into the groove 1d on the outer diameter surface of the outer member 1. Next, the cylindrical protective cover 29 is press-fitted into the outer diameter surface from the outboard side of the outer member 1, the end of the inboard side is fitted to the outer diameter surface of the outer member 1, and the outboard side The sensor assembly 28 is covered with a protective cover 29 by attaching the end to the outer diameter surface of the outer member 1 via the O-ring 30. After this, the entire bearing is assembled. By assembling in this procedure, the sensor-equipped wheel bearing in which the sensor assembly 28 attached to the outer member 1 is covered with the protective cover 29 can be easily assembled.

  The load detection operation by the wheel bearing with sensor will be described below. 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 outer diameter 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 is detected with high sensitivity, the hysteresis generated in the output signal is also reduced, and the load can be estimated with high accuracy. In particular, an electronic component including a plurality of sensor units 20, a signal processing unit 26 for processing the output signal of the strain sensor 22, and a signal cable 27 for extracting the processed output signal to the outside of the bearing is connected in a ring shape. The sensor assembly 28 is attached to the outer diameter surface of the outer member 1 concentrically with the outer member 1, and the sensor assembly 28 is covered with a cylindrical protective cover 29 whose inner diameter increases toward the inboard side. Cover the inboard side end of the protective cover 29 with the outer diameter surface of the outer member 1, and attach the outboard side end of the protective cover 29 to the outer diameter surface of the outer member 1 via the O-ring 30. Therefore, it is possible to prevent the electronic components including the sensor unit 20 from being damaged by the external environment (damage due to stepping stones, corrosion due to muddy water, salt water, etc.) and accurately detect the load over a long period of time. Can. In addition, wiring processing of the signal cable 27 and assembly of the sensor unit 20 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 the case of this embodiment in which the fixed side member is the outer member 1, the protective cover 29 is attached to the outer diameter surface of the outer member 1. Easy to protect.

  In this embodiment, the protective cover 29 has a stepped cylindrical shape with a large diameter on the inboard side. Therefore, the protective cover 29 extends from the outboard side of the outer member 1 to the outer diameter surface of the outer member 1. Can be easily press-fitted.

  Moreover, in this embodiment, since the metal material or the resin material is used as the material of the protective cover 29, the outer member 1 can be attached to the outer diameter surface with good sealing performance. That is, when a metal material is used as the material of the protective cover 29, the protective cover 29 can be firmly attached to the outer diameter surface of the outer member 1 with good sealing performance. Further, when a resin material is used as the material of the protective cover 29, the protective cover 29 can be easily formed as a molded product and can be attached to the outer diameter surface of the outer member 1 with good sealing performance. Thereby, the failure of the sensor due to the influence of the external environment can be prevented more reliably.

  If the axial dimension of each contact fixing portion 21a of the strain generating member 21 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 outer member 1 through the contact fixing portion 21a. The strain transmitted to the strain generating member 21 is also different. In this embodiment, since each contact fixing part 21a of the strain generating member 21 of the sensor unit 20 is provided at a position having the same dimension in the axial direction, the strain is easily concentrated on the strain generating member 21, and the detection sensitivity is accordingly increased. Will improve. Further, since the sensor units 20 are arranged at the same axial position in the outer member 1, the sensor assembly 28 made of electronic components including the sensor unit 20 is covered only by providing the protective cover 29 at the axial position. The protective cover 29 can be configured in a compact manner.

  Further, in this embodiment, the strain generating member 21 of the sensor unit 20 is made of a thin plate material having a belt-like schematic shape as shown in FIG. 1 distortion is easily transmitted to the strain generating member 21, and the distortion is detected with high sensitivity by the strain sensor 22, 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.

Further, in this embodiment, the sensor unit 20 is configured such that the upper surface portion, the lower surface portion, the right surface portion, and the left surface of the outer diameter surface of the outer member 1 that is the fixed side member that is the vertical position and the left and right positions with respect to the tire ground contact surface. Since it arrange | positions to a surface part, a load can be estimated with high precision under any load conditions. That is, when a load in a certain direction increases, a portion where the rolling element 5 and the rolling surface 3 are in contact with each other and a portion which is not in contact appear with a phase difference of 180 degrees. If it is installed with a phase difference, the load applied to the outer member 1 is always transmitted to 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 where the sensor unit 20 is provided on the outer diameter surface of the outer member 1 are intermediate positions of the interval A between the left and right projecting 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 B between the projecting pieces 1aa vertically adjacent to each other 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.

  FIG. 12 shows another embodiment of the present invention. In this sensor wheel bearing, in the embodiment shown in FIGS. 1 to 11, an inward flange 29 c is formed on the outboard side end of the protective cover 29, and the outer diameter surface of the outer member 1 that is a stationary member. Provided with a protrusion 31 extending in the circumferential direction and facing the inward flange 29c of the protective cover 20 in the axial direction, and sandwiching the O-ring 30 between the protrusion 31 and the inward flange 29c of the protective cover 29 It is said. Other configurations are the same as those in the embodiment of FIGS.

  Thus, when the O-ring 30 is sandwiched between the inward flange 29c of the protective cover 29 and the protrusion 31 extending in the circumferential direction of the outer diameter surface of the outer member 1, the O-ring 30 is positioned in the axial direction. In addition, the space between the outboard side end of the protective cover 29 and the outer diameter surface of the outer member 1 is securely sealed.

  FIG. 13 shows still another embodiment of the present invention. In the wheel bearing with sensor, in the embodiment shown in FIGS. 1 to 11, the entire protective cover 29 is made of a resin material, and the inboard side end of the outer cover 1 is fitted to the outer diameter surface. A metal material 34 is embedded. Other configurations are the same as those in the embodiment of FIGS.

  As described above, when the metal material 34 is embedded in the inboard side end of the protective cover 29 made of a resin material, the outer cover 1 is firmly fitted to the outer diameter surface of the protective cover 29 at the inboard side end. In addition, it can be performed with good sealing performance, and the protective cover 29 can be easily formed.

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 the first or second generation type wheel bearing in which the bearing portion and the hub are independent parts, 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 , as a reference proposal example, the present invention can also 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.

DESCRIPTION OF SYMBOLS 1 ... Outer member 1d ... Protection cover fitting groove | channel 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 20 ... Sensor unit 21 ... Strain generating member 21a ... Contact fixing | fixed part 21b ... Notch part 22 ... Strain Sensor 26 ... IC for signal processing
27 ... Signal cable 27a ... Signal cable drawer 28 ... Sensor assembly 29 ... Protective cover 29c ... Inward flange 30 ... O-ring (seal ring)
31 ... ridge 32 ... notch 33 of outer member ... notch of protective cover

Claims (17)

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,
A plurality of sensor units for load detection, which is fixed to the outer peripheral surface of the outer member, and a signal processing IC for processing the output signal of the sensor unit, signal cable to take out processed the output signal to the outside of the bearing the sensor assembly formed by connecting in a ring shape an electronic component including bets, with attached to the outer peripheral surface of the outer member to the outer member concentric, inner diameter toward the sensor assembly on the inboard side expansion to covered with a cylindrical protection cover, the inboard side end of the protective cover is fitted to the outer peripheral surface of the outer member, the outer member through the seal ring of the elastic body outboard side end of the protective cover attached only to the outer peripheral surface of the sensor unit includes a strain generating member fixed in contact with the outer peripheral surface provided along the outer peripheral surface of the outer member, the strain attached to the strain generating member A strain sensor that detects strain of the raw member, and the strain generating member has a flat planar shape with a uniform width over the entire length and has notches on both sides of the center, and the strain sensor generates the strain. At the outer surface side of the member, it is attached to the central portion between the notch portions on both side portions, and the intermediate portion where the notch portion of the strain generating member is located is not in contact with the outer peripheral surface of the outer member. A sensor-equipped wheel bearing. 2. The sensor-equipped wheel bearing according to claim 1 , wherein the protective cover is a stepped cylindrical shape having a large diameter on the inboard side. 3. The wheel bearing with sensor according to claim 1 , wherein the material of the protective cover is a metal material or a resin material. 3. The sensor-equipped wheel according to claim 1 , wherein the entire protective cover is made of a resin material, and a metal material is embedded in a fitting portion of the inboard side end to the outer peripheral surface of the outer member . bearing. In any one of claims 1 to 4, the outer peripheral surface of the outboard grooves extending in the circumferential direction is provided on the side, said seal ring fitting the sensor equipped wheel support bearing assembly of the groove of the member. In any one of claims 1 to 4, wherein to form the inward flange the outboard side end of the protective cover, the outer inwardly of the protective cover on the outer peripheral surface extending in the circumferential direction of the member A sensor-equipped wheel bearing in which a ridge facing the flange in the axial direction is provided, and the seal ring is sandwiched between the ridge and the inward flange of the protective cover. The wheel bearing with sensor according to any one of claims 1 to 6 , wherein the seal ring is made of a rubber material. In any one of Claims 1 thru | or 6 , Out of the outer peripheral surface of the said outer member , and the fitting part which the said protective cover fits in each other, at least one part of one fitting part WHEREIN: A sensor-equipped wheel bearing in which a notch portion from which a lead portion of the signal cable is drawn out from the protective cover is provided, and a portion in which the signal cable lead portion is drawn out from the notch portion is filled with a sealing material. In any one of claim 1 to claim 8, wherein the outer peripheral surface with which the sensor equipped wheel support bearing assembly which is fixed to the member the sensor unit and the signal processing IC in the sensor assembly is in said protective cover. In any one of claim 1 to claim 9, sensor equipped wheel support bearing assembly elastic filler inside the protective cover is filled. In any one of claims 1 to 10, wherein the outer rust on the outer peripheral surface is that the sensor equipped wheel support bearing assembly which is decorated members. In any one of claims 1 to 11, wherein the sensor unit comprises one or more strain sensors for detecting front and Kiibitsu seen generating member, the distortion of the attached to the strain onset producing member in the strain generating member A sensor-equipped wheel bearing that detects deformation applied to the wheel bearing by detecting deformation of the outer member from an output signal of a strain sensor. The distortion generating member according to claim 12 , wherein the strain generating member has two or more contact fixing portions fixed in contact with an outer peripheral surface of the outer member , and the contact fixing portions are arranged with respect to the axial direction of the outer member. Sensor wheel bearings installed at the same position. According to claim 13, wherein the strain generating member, bearing with sensor wheel plane envelope is made of a thin plate material in strip. 15. The distortion generating member according to any one of claims 12 to 14 , wherein the strain generating member is applied with an assumed maximum force as an external force acting on the outer member or an acting force acting between the tire and a road surface. Sensor-equipped wheel bearing that is not plastically deformed even in a damaged state. 17. The sensor unit according to claim 1, wherein the sensor unit includes an upper surface portion, a lower surface portion, a right surface portion, and an outer peripheral surface of the outer member that are in a vertical position and a horizontal position with respect to a tire ground contact surface. Wheel bearing with sensor placed on the left side. The method of assembling a sensor-equipped wheel bearing according to any one of claims 1 to 16 , wherein the outer member is a single member or the rolling member is assembled to the outer member . mounting a seal ring of the sensor assembly and an elastic body on the outer peripheral surface of the outer member, wherein after the protective cover has been pressed to the outer peripheral surface of the outer member, a bearing sensor wheeled, characterized in that assembling the bearing Assembly method.

Images